Adding upstream version 4.94.2.upstream/4.94.2upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

17 files changed, 13574 insertions, 0 deletions

diff --git a/src/transports/Makefile b/src/transports/Makefile
new file mode 100644
index 0000000..4eea141
--- /dev/null
+++ b/src/transports/Makefile
@@ -0,0 +1,27 @@
+# Make file for building a library containing all the available transports and
+# calling it transports.a. This is called from the main make file, after cd'ing
+# to the transports subdirectory.
+
+OBJ = appendfile.o autoreply.o lmtp.o pipe.o queuefile.o smtp.o smtp_socks.o tf_maildir.o
+
+transports.a:    $(OBJ)
+		 @$(RM_COMMAND) -f transports.a
+		 @echo "$(AR) transports.a"
+		 @$(AR) transports.a $(OBJ)
+		 $(RANLIB) $@
+
+.SUFFIXES:       .o .c
+.c.o:;           @echo "$(CC) $*.c"
+		 $(FE)$(CC) -c $(CFLAGS) $(INCLUDE) $*.c
+
+appendfile.o:    $(HDRS) appendfile.c appendfile.h tf_maildir.h
+autoreply.o:     $(HDRS) autoreply.c autoreply.h
+lmtp.o:          $(HDRS) lmtp.c lmtp.h
+pipe.o:          $(HDRS) pipe.c pipe.h
+queuefile.o:     $(HDRS) queuefile.c queuefile.h
+smtp.o:          $(HDRS) smtp.c smtp.h
+smtp_socks.o:    $(HDRS) smtp_socks.c smtp.h
+
+tf_maildir.o:    $(HDRS) tf_maildir.c tf_maildir.h appendfile.h
+
+# End
diff --git a/src/transports/README b/src/transports/README
new file mode 100644
index 0000000..9ea29fb
--- /dev/null
+++ b/src/transports/README
@@ -0,0 +1,41 @@
+TRANSPORTS:
+
+A delivery attempt results in one of the following values being placed in
+addr->transport_return:
+
+    OK          success
+    DEFER       temporary failure
+    FAIL        permanent failure
+    PANIC       disaster - causes exim to bomb
+
+The field is initialized to DEFER when the address is created, in order that
+unexpected process crashes or other problems don't cause the message to be
+deleted.
+
+For non-OK values, additional information is placed in addr->errno,
+addr->more_errno, and optionally in addr->message. These are inspected only if
+the status is not OK, with one exception (see below).
+
+In addition, the addr->special_action field can be set to request a non-default
+action. The default action after FAIL is to return to sender; the default
+action after DEFER is nothing. The alternatives are:
+
+  SPECIAL_NONE       (default) no special action
+  SPECIAL_FREEZE     freeze the message
+  SPECIAL_WARN       send warning message
+
+The SPECIAL_WARN action is the exception referred to above. It is picked up
+only after a *successful* delivery; it causes a warning message to be sent
+containing the text of warn_message to warn_to. It can be used in appendfile,
+for example, to send a warning message when the mailbox size crosses a given
+threshold.
+
+If the transport is handling a batch of several addresses, it may either put an
+individual value in each address structure, and return TRUE, or it may put a
+common value in the first address, and return FALSE.
+
+Remote transports usually return TRUE and local transports usually return
+FALSE; however, the lmtp transport may return either value, depending on what
+happens inside it.
+
+****
diff --git a/src/transports/appendfile.c b/src/transports/appendfile.c
new file mode 100644
index 0000000..8ab8b60
--- /dev/null
+++ b/src/transports/appendfile.c
@@ -0,0 +1,3318 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+/* Copyright (c) University of Cambridge 1995 - 2018 */
+/* Copyright (c) The Exim maintainers 2020 */
+/* See the file NOTICE for conditions of use and distribution. */
+
+
+#include "../exim.h"
+#include "appendfile.h"
+
+#ifdef SUPPORT_MAILDIR
+#include "tf_maildir.h"
+#endif
+
+
+/* Options specific to the appendfile transport. They must be in alphabetic
+order (note that "_" comes before the lower case letters). Some of them are
+stored in the publicly visible instance block - these are flagged with the
+opt_public flag. */
+#define LOFF(field) OPT_OFF(appendfile_transport_options_block, field)
+
+optionlist appendfile_transport_options[] = {
+#ifdef SUPPORT_MAILDIR
+  { "*expand_maildir_use_size_file", opt_stringptr, LOFF(expand_maildir_use_size_file) },
+#endif
+  { "*set_use_fcntl_lock",opt_bool | opt_hidden, LOFF(set_use_fcntl) },
+  { "*set_use_flock_lock",opt_bool | opt_hidden, LOFF(set_use_flock) },
+  { "*set_use_lockfile", opt_bool | opt_hidden,	LOFF(set_use_lockfile) },
+#ifdef SUPPORT_MBX
+  { "*set_use_mbx_lock", opt_bool | opt_hidden,	LOFF(set_use_mbx_lock) },
+#endif
+  { "allow_fifo",        opt_bool,	LOFF(allow_fifo) },
+  { "allow_symlink",     opt_bool,	LOFF(allow_symlink) },
+  { "batch_id",          opt_stringptr | opt_public, OPT_OFF(transport_instance, batch_id) },
+  { "batch_max",         opt_int | opt_public, OPT_OFF(transport_instance, batch_max) },
+  { "check_group",       opt_bool,	LOFF(check_group) },
+  { "check_owner",       opt_bool,	LOFF(check_owner) },
+  { "check_string",      opt_stringptr,	LOFF(check_string) },
+  { "create_directory",  opt_bool,	LOFF(create_directory) },
+  { "create_file",       opt_stringptr,	LOFF(create_file_string) },
+  { "directory",         opt_stringptr,	LOFF(dirname) },
+  { "directory_file",    opt_stringptr,	LOFF(dirfilename) },
+  { "directory_mode",    opt_octint,	LOFF(dirmode) },
+  { "escape_string",     opt_stringptr,	LOFF(escape_string) },
+  { "file",              opt_stringptr,	LOFF(filename) },
+  { "file_format",       opt_stringptr,	LOFF(file_format) },
+  { "file_must_exist",   opt_bool,	LOFF(file_must_exist) },
+  { "lock_fcntl_timeout", opt_time,	LOFF(lock_fcntl_timeout) },
+  { "lock_flock_timeout", opt_time,	LOFF(lock_flock_timeout) },
+  { "lock_interval",     opt_time,	LOFF(lock_interval) },
+  { "lock_retries",      opt_int,	LOFF(lock_retries) },
+  { "lockfile_mode",     opt_octint,	LOFF(lockfile_mode) },
+  { "lockfile_timeout",  opt_time,	LOFF(lockfile_timeout) },
+  { "mailbox_filecount", opt_stringptr,	LOFF(mailbox_filecount_string) },
+  { "mailbox_size",      opt_stringptr,	LOFF(mailbox_size_string) },
+#ifdef SUPPORT_MAILDIR
+  { "maildir_format",    opt_bool,	LOFF(maildir_format ) } ,
+  { "maildir_quota_directory_regex", opt_stringptr, LOFF(maildir_dir_regex) },
+  { "maildir_retries",   opt_int,	LOFF(maildir_retries) },
+  { "maildir_tag",       opt_stringptr,	LOFF(maildir_tag) },
+  { "maildir_use_size_file", opt_expand_bool, LOFF(maildir_use_size_file ) } ,
+  { "maildirfolder_create_regex", opt_stringptr, LOFF(maildirfolder_create_regex ) },
+#endif  /* SUPPORT_MAILDIR */
+#ifdef SUPPORT_MAILSTORE
+  { "mailstore_format",  opt_bool,	LOFF(mailstore_format ) },
+  { "mailstore_prefix",  opt_stringptr,	LOFF(mailstore_prefix ) },
+  { "mailstore_suffix",  opt_stringptr,	LOFF(mailstore_suffix ) },
+#endif  /* SUPPORT_MAILSTORE */
+#ifdef SUPPORT_MBX
+  { "mbx_format",        opt_bool,	LOFF(mbx_format ) } ,
+#endif  /* SUPPORT_MBX */
+  { "message_prefix",    opt_stringptr,	LOFF(message_prefix) },
+  { "message_suffix",    opt_stringptr,	LOFF(message_suffix) },
+  { "mode",              opt_octint,	LOFF(mode) },
+  { "mode_fail_narrower",opt_bool,	LOFF(mode_fail_narrower) },
+  { "notify_comsat",     opt_bool,	LOFF(notify_comsat) },
+  { "quota",             opt_stringptr,	LOFF(quota) },
+  { "quota_directory",   opt_stringptr,	LOFF(quota_directory) },
+  { "quota_filecount",   opt_stringptr,	LOFF(quota_filecount) },
+  { "quota_is_inclusive", opt_bool,	LOFF(quota_is_inclusive) },
+  { "quota_size_regex",   opt_stringptr, LOFF(quota_size_regex) },
+  { "quota_warn_message", opt_stringptr | opt_public, OPT_OFF(transport_instance, warn_message) },
+  { "quota_warn_threshold", opt_stringptr, LOFF(quota_warn_threshold) },
+  { "use_bsmtp",         opt_bool,	LOFF(use_bsmtp) },
+  { "use_crlf",          opt_bool,	LOFF(use_crlf) },
+  { "use_fcntl_lock",    opt_bool_set,	LOFF(use_fcntl) },
+  { "use_flock_lock",    opt_bool_set,	LOFF(use_flock) },
+  { "use_lockfile",      opt_bool_set,	LOFF(use_lockfile) },
+#ifdef SUPPORT_MBX
+  { "use_mbx_lock",      opt_bool_set,	LOFF(use_mbx_lock) },
+#endif  /* SUPPORT_MBX */
+};
+
+/* Size of the options list. An extern variable has to be used so that its
+address can appear in the tables drtables.c. */
+
+int appendfile_transport_options_count =
+  sizeof(appendfile_transport_options)/sizeof(optionlist);
+
+
+#ifdef MACRO_PREDEF
+
+/* Dummy values */
+appendfile_transport_options_block appendfile_transport_option_defaults = {0};
+void appendfile_transport_init(transport_instance *tblock) {}
+BOOL appendfile_transport_entry(transport_instance *tblock, address_item *addr) {return FALSE;}
+
+#else	/*!MACRO_PREDEF*/
+
+/* Default private options block for the appendfile transport. */
+
+appendfile_transport_options_block appendfile_transport_option_defaults = {
+  NULL,           /* filename */
+  NULL,           /* dirname */
+  US"q${base62:$tod_epoch}-$inode", /* dirfilename */
+  NULL,           /* message_prefix (default reset in init if not bsmtp) */
+  NULL,           /* message_suffix (ditto) */
+  US"anywhere",   /* create_file_string (string value for create_file) */
+  NULL,           /* quota */
+  NULL,           /* quota_directory */
+  NULL,           /* quota_filecount */
+  NULL,           /* quota_size_regex */
+  NULL,           /* quota_warn_threshold */
+  NULL,           /* mailbox_size_string */
+  NULL,           /* mailbox_filecount_string */
+  NULL,           /* expand_maildir_use_size_file */
+  US"^(?:cur|new|\\..*)$",  /* maildir_dir_regex */
+  NULL,           /* maildir_tag */
+  NULL,           /* maildirfolder_create_regex */
+  NULL,           /* mailstore_prefix */
+  NULL,           /* mailstore_suffix */
+  NULL,           /* check_string (default changed for non-bsmtp file)*/
+  NULL,           /* escape_string (ditto) */
+  NULL,           /* file_format */
+  0,              /* quota_value */
+  0,              /* quota_warn_threshold_value */
+  -1,             /* mailbox_size_value */
+  -1,             /* mailbox_filecount_value */
+  0,              /* quota_filecount_value */
+  APPENDFILE_MODE,           /* mode */
+  APPENDFILE_DIRECTORY_MODE, /* dirmode */
+  APPENDFILE_LOCKFILE_MODE,  /* lockfile_mode */
+  30*60,          /* lockfile_timeout */
+  0,              /* lock_fcntl_timeout */
+  0,              /* lock_flock_timeout */
+  10,             /* lock_retries */
+   3,             /* lock_interval */
+  10,             /* maildir_retries */
+  create_anywhere,/* create_file */
+  0,              /* options */
+  FALSE,          /* allow_fifo */
+  FALSE,          /* allow_symlink */
+  FALSE,          /* check_group */
+  TRUE,           /* check_owner */
+  TRUE,           /* create_directory */
+  FALSE,          /* notify_comsat */
+  TRUE,           /* use_lockfile */
+  FALSE,          /* set_use_lockfile */
+  TRUE,           /* use_fcntl */
+  FALSE,          /* set_use_fcntl */
+  FALSE,          /* use_flock */
+  FALSE,          /* set_use_flock */
+  FALSE,          /* use_mbx_lock */
+  FALSE,          /* set_use_mbx_lock */
+  FALSE,          /* use_bsmtp */
+  FALSE,          /* use_crlf */
+  FALSE,          /* file_must_exist */
+  TRUE,           /* mode_fail_narrower */
+  FALSE,          /* maildir_format */
+  FALSE,          /* maildir_use_size_file */
+  FALSE,          /* mailstore_format */
+  FALSE,          /* mbx_format */
+  FALSE,          /* quota_warn_threshold_is_percent */
+  TRUE,           /* quota_is_inclusive */
+  FALSE,          /* quota_no_check */
+  FALSE           /* quota_filecount_no_check */
+};
+
+
+/* Encodings for mailbox formats, and their names. MBX format is actually
+supported only if SUPPORT_MBX is set. */
+
+enum { mbf_unix, mbf_mbx, mbf_smail, mbf_maildir, mbf_mailstore };
+
+static const char *mailbox_formats[] = {
+  "unix", "mbx", "smail", "maildir", "mailstore" };
+
+
+/* Check warn threshold only if quota size set or not a percentage threshold
+   percentage check should only be done if quota > 0 */
+
+#define THRESHOLD_CHECK  (ob->quota_warn_threshold_value > 0 && \
+  (!ob->quota_warn_threshold_is_percent || ob->quota_value > 0))
+
+
+
+/*************************************************
+*              Setup entry point                 *
+*************************************************/
+
+/* Called for each delivery in the privileged state, just before the uid/gid
+are changed and the main entry point is called. We use this function to
+expand any quota settings, so that it can access files that may not be readable
+by the user. It is also used to pick up external mailbox size information, if
+set.
+
+Arguments:
+  tblock     points to the transport instance
+  addrlist   addresses about to be delivered (not used)
+  dummy      not used (doesn't pass back data)
+  uid        the uid that will be set (not used)
+  gid        the gid that will be set (not used)
+  errmsg     where to put an error message
+
+Returns:     OK, FAIL, or DEFER
+*/
+
+static int
+appendfile_transport_setup(transport_instance *tblock, address_item *addrlist,
+  transport_feedback *dummy, uid_t uid, gid_t gid, uschar **errmsg)
+{
+appendfile_transport_options_block *ob =
+  (appendfile_transport_options_block *)(tblock->options_block);
+uschar *q = ob->quota;
+double default_value = 0.0;
+
+addrlist = addrlist;    /* Keep picky compilers happy */
+dummy = dummy;
+uid = uid;
+gid = gid;
+
+if (ob->expand_maildir_use_size_file)
+	ob->maildir_use_size_file = expand_check_condition(ob->expand_maildir_use_size_file,
+		US"`maildir_use_size_file` in transport", tblock->name);
+
+/* Loop for quota, quota_filecount, quota_warn_threshold, mailbox_size,
+mailbox_filecount */
+
+for (int i = 0; i < 5; i++)
+  {
+  double d;
+  int no_check = 0;
+  uschar *which = NULL;
+
+  if (q == NULL) d = default_value;
+  else
+    {
+    uschar *rest;
+    uschar *s = expand_string(q);
+
+    if (!s)
+      {
+      *errmsg = string_sprintf("Expansion of \"%s\" in %s transport failed: "
+        "%s", q, tblock->name, expand_string_message);
+      return f.search_find_defer ? DEFER : FAIL;
+      }
+
+    d = Ustrtod(s, &rest);
+
+    /* Handle following characters K, M, G, %, the latter being permitted
+    for quota_warn_threshold only. A threshold with no quota setting is
+    just ignored. */
+
+    if (tolower(*rest) == 'k') { d *= 1024.0; rest++; }
+    else if (tolower(*rest) == 'm') { d *= 1024.0*1024.0; rest++; }
+    else if (tolower(*rest) == 'g') { d *= 1024.0*1024.0*1024.0; rest++; }
+    else if (*rest == '%' && i == 2)
+      {
+      if (ob->quota_value <= 0 && !ob->maildir_use_size_file)
+	d = 0;
+      else if ((int)d < 0 || (int)d > 100)
+        {
+        *errmsg = string_sprintf("Invalid quota_warn_threshold percentage (%d)"
+          " for %s transport", (int)d, tblock->name);
+        return FAIL;
+        }
+      ob->quota_warn_threshold_is_percent = TRUE;
+      rest++;
+      }
+
+
+    /* For quota and quota_filecount there may be options
+    appended. Currently only "no_check", so we can be lazy parsing it */
+    if (i < 2 && Ustrstr(rest, "/no_check") == rest)
+      {
+       no_check = 1;
+       rest += sizeof("/no_check") - 1;
+      }
+
+    Uskip_whitespace(&rest);
+
+    if (*rest)
+      {
+      *errmsg = string_sprintf("Malformed value \"%s\" (expansion of \"%s\") "
+        "in %s transport", s, q, tblock->name);
+      return FAIL;
+      }
+    }
+
+  /* Set each value, checking for possible overflow. */
+
+  switch (i)
+    {
+    case 0:
+      if (d >= 2.0*1024.0*1024.0*1024.0 && sizeof(off_t) <= 4)
+	which = US"quota";
+      ob->quota_value = (off_t)d;
+      ob->quota_no_check = no_check;
+      q = ob->quota_filecount;
+      break;
+
+    case 1:
+      if (d >= 2.0*1024.0*1024.0*1024.0)
+	which = US"quota_filecount";
+      ob->quota_filecount_value = (int)d;
+      ob->quota_filecount_no_check = no_check;
+      q = ob->quota_warn_threshold;
+      break;
+
+    case 2:
+    if (d >= 2.0*1024.0*1024.0*1024.0 && sizeof(off_t) <= 4)
+	which = US"quota_warn_threshold";
+      ob->quota_warn_threshold_value = (off_t)d;
+      q = ob->mailbox_size_string;
+      default_value = -1.0;
+      break;
+
+    case 3:
+      if (d >= 2.0*1024.0*1024.0*1024.0 && sizeof(off_t) <= 4)
+	which = US"mailbox_size";;
+      ob->mailbox_size_value = (off_t)d;
+      q = ob->mailbox_filecount_string;
+      break;
+
+    case 4:
+      if (d >= 2.0*1024.0*1024.0*1024.0)
+	which = US"mailbox_filecount";
+      ob->mailbox_filecount_value = (int)d;
+      break;
+    }
+
+  if (which)
+    {
+    *errmsg = string_sprintf("%s value %.10g is too large (overflow) in "
+      "%s transport", which, d, tblock->name);
+    return FAIL;
+    }
+  }
+
+return OK;
+}
+
+
+
+/*************************************************
+*          Initialization entry point            *
+*************************************************/
+
+/* Called for each instance, after its options have been read, to
+enable consistency checks to be done, or anything else that needs
+to be set up. */
+
+void
+appendfile_transport_init(transport_instance *tblock)
+{
+appendfile_transport_options_block *ob =
+  (appendfile_transport_options_block *)(tblock->options_block);
+
+/* Set up the setup entry point, to be called in the privileged state */
+
+tblock->setup = appendfile_transport_setup;
+
+/* Lock_retries must be greater than zero */
+
+if (ob->lock_retries == 0) ob->lock_retries = 1;
+
+/* Only one of a file name or directory name must be given. */
+
+if (ob->filename && ob->dirname)
+  log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s transport:\n  "
+  "only one of \"file\" or \"directory\" can be specified", tblock->name);
+
+/* If a file name was specified, neither quota_filecount nor quota_directory
+must be given. */
+
+if (ob->filename)
+  {
+  if (ob->quota_filecount)
+    log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s transport:\n  "
+      "quota_filecount must not be set without \"directory\"", tblock->name);
+  if (ob->quota_directory)
+    log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s transport:\n  "
+      "quota_directory must not be set without \"directory\"", tblock->name);
+  }
+
+/* The default locking depends on whether MBX is set or not. Change the
+built-in default if none of the lock options has been explicitly set. At least
+one form of locking is required in all cases, but mbx locking changes the
+meaning of fcntl and flock locking. */
+
+/* Not all operating systems provide flock(). For those that do, if flock is
+requested, the default for fcntl is FALSE. */
+
+if (ob->use_flock)
+  {
+  #ifdef NO_FLOCK
+  log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s transport:\n  "
+    "flock() support was not available in the operating system when this "
+    "binary was built", tblock->name);
+  #endif  /* NO_FLOCK */
+  if (!ob->set_use_fcntl) ob->use_fcntl = FALSE;
+  }
+
+#ifdef SUPPORT_MBX
+if (ob->mbx_format)
+  if (!ob->set_use_lockfile && !ob->set_use_fcntl && !ob->set_use_flock &&
+      !ob->set_use_mbx_lock)
+    {
+    ob->use_lockfile = ob->use_flock = FALSE;
+    ob->use_mbx_lock = ob->use_fcntl = TRUE;
+    }
+  else if (ob->use_mbx_lock)
+    {
+    if (!ob->set_use_lockfile) ob->use_lockfile = FALSE;
+    if (!ob->set_use_fcntl) ob->use_fcntl = FALSE;
+    if (!ob->set_use_flock) ob->use_flock = FALSE;
+    if (!ob->use_fcntl && !ob->use_flock) ob->use_fcntl = TRUE;
+    }
+#endif  /* SUPPORT_MBX */
+
+if (!ob->use_fcntl && !ob->use_flock && !ob->use_lockfile && !ob->use_mbx_lock)
+  log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s transport:\n  "
+    "no locking configured", tblock->name);
+
+/* Unset timeouts for non-used locking types */
+
+if (!ob->use_fcntl) ob->lock_fcntl_timeout = 0;
+if (!ob->use_flock) ob->lock_flock_timeout = 0;
+
+/* If a directory name was specified, only one of maildir or mailstore may be
+specified, and if quota_filecount or quota_directory is given, quota must
+be set. */
+
+if (ob->dirname)
+  {
+  if (ob->maildir_format && ob->mailstore_format)
+    log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s transport:\n  "
+      "only one of maildir and mailstore may be specified", tblock->name);
+  if (ob->quota_filecount != NULL && ob->quota == NULL)
+    log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s transport:\n  "
+      "quota must be set if quota_filecount is set", tblock->name);
+  if (ob->quota_directory != NULL && ob->quota == NULL)
+    log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s transport:\n  "
+      "quota must be set if quota_directory is set", tblock->name);
+  }
+
+/* If a fixed uid field is set, then a gid field must also be set. */
+
+if (tblock->uid_set && !tblock->gid_set && !tblock->expand_gid)
+  log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
+    "user set without group for the %s transport", tblock->name);
+
+/* If "create_file" is set, check that a valid option is given, and set the
+integer variable. */
+
+if (ob->create_file_string)
+  {
+  int value = 0;
+  if (Ustrcmp(ob->create_file_string, "anywhere") == 0)
+    value = create_anywhere;
+  else if (Ustrcmp(ob->create_file_string, "belowhome") == 0)
+    value = create_belowhome;
+  else if (Ustrcmp(ob->create_file_string, "inhome") == 0)
+    value = create_inhome;
+  else
+    log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
+      "invalid value given for \"file_create\" for the %s transport: %s",
+        tblock->name, ob->create_file_string);
+  ob->create_file = value;
+  }
+
+/* If quota_warn_threshold is set, set up default for warn_message. It may
+not be used if the actual threshold for a given delivery ends up as zero,
+of if it's given as a percentage and there's no quota setting. */
+
+if (ob->quota_warn_threshold)
+  {
+  if (!tblock->warn_message) tblock->warn_message = US
+    "To: $local_part@$domain\n"
+    "Subject: Your mailbox\n\n"
+    "This message is automatically created by mail delivery software (Exim).\n\n"
+    "The size of your mailbox has exceeded a warning threshold that is\n"
+    "set by the system administrator.\n";
+  }
+
+/* If batch SMTP is set, force the check and escape strings, and arrange that
+headers are also escaped. */
+
+if (ob->use_bsmtp)
+  {
+  ob->check_string = US".";
+  ob->escape_string = US"..";
+  ob->options |= topt_escape_headers;
+  }
+
+/* If not batch SMTP, not maildir, not mailstore, and directory is not set,
+insert default values for for the affixes and the check/escape strings. */
+
+else if (!ob->dirname && !ob->maildir_format && !ob->mailstore_format)
+  {
+  if (!ob->message_prefix) ob->message_prefix =
+    US"From ${if def:return_path{$return_path}{MAILER-DAEMON}} ${tod_bsdinbox}\n";
+  if (!ob->message_suffix) ob->message_suffix = US"\n";
+  if (!ob->check_string) ob->check_string = US"From ";
+  if (!ob->escape_string) ob->escape_string = US">From ";
+
+  }
+
+/* Set up the bitwise options for transport_write_message from the various
+driver options. Only one of body_only and headers_only can be set. */
+
+ob->options |=
+  (tblock->body_only ? topt_no_headers : 0) |
+  (tblock->headers_only ? topt_no_body : 0) |
+  (tblock->return_path_add ? topt_add_return_path : 0) |
+  (tblock->delivery_date_add ? topt_add_delivery_date : 0) |
+  (tblock->envelope_to_add ? topt_add_envelope_to : 0) |
+  ((ob->use_crlf || ob->mbx_format) ? topt_use_crlf : 0);
+}
+
+
+
+/*************************************************
+*                  Notify comsat                 *
+*************************************************/
+
+/* The comsat daemon is the thing that provides asynchronous notification of
+the arrival of local messages, if requested by the user by "biff y". It is a
+BSD thing that uses a TCP/IP protocol for communication. A message consisting
+of the text "user@offset" must be sent, where offset is the place in the
+mailbox where new mail starts. There is no scope for telling it which file to
+look at, which makes it a less than useful if mail is being delivered into a
+non-standard place such as the user's home directory. In fact, it doesn't seem
+to pay much attention to the offset.
+
+Arguments:
+  user       user name
+  offset     offset in mailbox
+
+Returns:     nothing
+*/
+
+static void
+notify_comsat(uschar *user, off_t offset)
+{
+struct servent *sp;
+host_item host;
+uschar * s;
+
+DEBUG(D_transport) debug_printf("notify_comsat called\n");
+
+s = string_sprintf("%.200s@" OFF_T_FMT "\n", user, offset);
+
+if ((sp = getservbyname("biff", "udp")) == NULL)
+  {
+  DEBUG(D_transport) debug_printf("biff/udp is an unknown service");
+  return;
+  }
+
+host.name = US"localhost";
+host.next = NULL;
+
+
+/* This code is all set up to look up "localhost" and use all its addresses
+until one succeeds. However, it appears that at least on some systems, comsat
+doesn't listen on the ::1 address. So for the moment, just force the address to
+be 127.0.0.1. At some future stage, when IPv6 really is superseding IPv4, this
+can be changed. (But actually, comsat is probably dying out anyway.) */
+
+/******
+if (host_find_byname(&host, NULL, 0, NULL, FALSE) == HOST_FIND_FAILED)
+  {
+  DEBUG(D_transport) debug_printf("\"localhost\" unknown\n");
+  return;
+  }
+******/
+
+host.address = US"127.0.0.1";
+
+
+for (host_item * h = &host; h; h = h->next)
+  {
+  int sock, rc;
+  int host_af = Ustrchr(h->address, ':') != NULL ? AF_INET6 : AF_INET;
+
+  DEBUG(D_transport) debug_printf("calling comsat on %s\n", h->address);
+
+  if ((sock = ip_socket(SOCK_DGRAM, host_af)) < 0) continue;
+
+  /* Connect never fails for a UDP socket, so don't set a timeout. */
+
+  (void)ip_connect(sock, host_af, h->address, ntohs(sp->s_port), 0, NULL);
+  rc = send(sock, s, Ustrlen(s) + 1, 0);
+  (void)close(sock);
+
+  if (rc >= 0) break;
+  DEBUG(D_transport)
+    debug_printf("send to comsat failed for %s: %s\n", strerror(errno),
+      h->address);
+  }
+}
+
+
+
+/*************************************************
+*     Check the format of a file                 *
+*************************************************/
+
+/* This function is called when file_format is set, to check that an existing
+file has the right format. The format string contains text/transport pairs. The
+string matching is literal. we just read big_buffer_size bytes, because this is
+all about the first few bytes of a file.
+
+Arguments:
+  cfd          the open file
+  tblock       the transport block
+  addr         the address block - for inserting error data
+
+Returns:       pointer to the required transport, or NULL
+*/
+
+transport_instance *
+check_file_format(int cfd, transport_instance *tblock, address_item *addr)
+{
+const uschar *format =
+  ((appendfile_transport_options_block *)(tblock->options_block))->file_format;
+uschar data[256];
+int len = read(cfd, data, sizeof(data));
+int sep = 0;
+uschar *s;
+
+DEBUG(D_transport) debug_printf("checking file format\n");
+
+/* An empty file matches the current transport */
+
+if (len == 0) return tblock;
+
+/* Search the formats for a match */
+
+while ((s = string_nextinlist(&format,&sep,big_buffer,big_buffer_size)))
+  {
+  int slen = Ustrlen(s);
+  BOOL match = len >= slen && Ustrncmp(data, s, slen) == 0;
+  uschar *tp = string_nextinlist(&format, &sep, big_buffer, big_buffer_size);
+
+  if (match && tp)
+    {
+    for (transport_instance * tt = transports; tt; tt = tt->next)
+      if (Ustrcmp(tp, tt->name) == 0)
+        {
+        DEBUG(D_transport)
+          debug_printf("file format -> %s transport\n", tt->name);
+        return tt;
+        }
+    addr->basic_errno = ERRNO_BADTRANSPORT;
+    addr->message = string_sprintf("%s transport (for %.*s format) not found",
+      tp, slen, data);
+    return NULL;
+    }
+  }
+
+/* Failed to find a match */
+
+addr->basic_errno = ERRNO_FORMATUNKNOWN;
+addr->message = US"mailbox file format unrecognized";
+return NULL;
+}
+
+
+
+
+/*************************************************
+*       Check directory's files for quota        *
+*************************************************/
+
+/* This function is called if quota is set for one of the delivery modes that
+delivers into a specific directory. It scans the directory and stats all the
+files in order to get a total size and count. This is an expensive thing to do,
+but some people are prepared to bear the cost. Alternatively, if size_regex is
+set, it is used as a regex to try to extract the size from the file name, a
+strategy that some people use on maildir files on systems where the users have
+no shell access.
+
+The function is global, because it is also called from tf_maildir.c for maildir
+folders (which should contain only regular files).
+
+Note: Any problems can be written to debugging output, but cannot be written to
+the log, because we are running as an unprivileged user here.
+
+Arguments:
+  dirname       the name of the directory
+  countptr      where to add the file count (because this function recurses)
+  regex         a compiled regex to get the size from a name
+
+Returns:        the sum of the sizes of the stattable files
+                zero if the directory cannot be opened
+*/
+
+off_t
+check_dir_size(const uschar * dirname, int *countptr, const pcre *regex)
+{
+DIR *dir;
+off_t sum = 0;
+int count = *countptr;
+
+if (!(dir = exim_opendir(dirname))) return 0;
+
+for (struct dirent *ent; ent = readdir(dir); )
+  {
+  uschar * path, * name = US ent->d_name;
+  struct stat statbuf;
+
+  if (Ustrcmp(name, ".") == 0 || Ustrcmp(name, "..") == 0) continue;
+
+  count++;
+
+  /* If there's a regex, try to find the size using it */
+
+  if (regex)
+    {
+    int ovector[6];
+    if (pcre_exec(regex, NULL, CS name, Ustrlen(name), 0, 0, ovector,6) >= 2)
+      {
+      uschar *endptr;
+      off_t size = (off_t)Ustrtod(name + ovector[2], &endptr);
+      if (endptr == name + ovector[3])
+        {
+        sum += size;
+        DEBUG(D_transport)
+          debug_printf("check_dir_size: size from %s is " OFF_T_FMT "\n", name,
+            size);
+        continue;
+        }
+      }
+    DEBUG(D_transport)
+      debug_printf("check_dir_size: regex did not match %s\n", name);
+    }
+
+  /* No regex or no match for the regex, or captured non-digits */
+
+  path = string_sprintf("%s/%s", dirname, name);
+
+  if (Ustat(path, &statbuf) < 0)
+    {
+    DEBUG(D_transport)
+      debug_printf("check_dir_size: stat error %d for %s: %s\n", errno, path,
+        strerror(errno));
+    }
+  else
+    if ((statbuf.st_mode & S_IFMT) == S_IFREG)
+      sum += statbuf.st_size / statbuf.st_nlink;
+    else if ((statbuf.st_mode & S_IFMT) == S_IFDIR)
+      sum += check_dir_size(path, &count, regex);
+  }
+
+closedir(dir);
+DEBUG(D_transport)
+  debug_printf("check_dir_size: dir=%s sum=" OFF_T_FMT " count=%d\n", dirname,
+    sum, count);
+
+*countptr = count;
+return sum;
+}
+
+
+
+
+/*************************************************
+*         Apply a lock to a file descriptor      *
+*************************************************/
+
+/* This function applies a lock to a file descriptor, using a blocking or
+non-blocking lock, depending on the timeout value. It can apply either or
+both of a fcntl() and a flock() lock. However, not all OS support flock();
+for those that don't, the use_flock option cannot be set.
+
+Arguments:
+  fd          the file descriptor
+  fcntltype   type of lock, specified as F_WRLCK or F_RDLCK (that is, in
+                fcntl() format); the flock() type is deduced if needed
+  dofcntl     do fcntl() locking
+  fcntltime   non-zero to use blocking fcntl()
+  doflock     do flock() locking
+  flocktime   non-zero to use blocking flock()
+
+Returns:      yield of the fcntl() or flock() call, with errno preserved;
+              sigalrm_seen set if there has been a timeout
+*/
+
+static int
+apply_lock(int fd, int fcntltype, BOOL dofcntl, int fcntltime, BOOL doflock,
+    int flocktime)
+{
+int yield = 0;
+int save_errno;
+struct flock lock_data;
+lock_data.l_type = fcntltype;
+lock_data.l_whence = lock_data.l_start = lock_data.l_len = 0;
+
+sigalrm_seen = FALSE;
+
+if (dofcntl)
+  {
+  if (fcntltime > 0)
+    {
+    ALARM(fcntltime);
+    yield = fcntl(fd, F_SETLKW, &lock_data);
+    save_errno = errno;
+    ALARM_CLR(0);
+    errno = save_errno;
+    }
+  else yield = fcntl(fd, F_SETLK, &lock_data);
+  }
+
+#ifndef NO_FLOCK
+if (doflock && (yield >= 0))
+  {
+  int flocktype = (fcntltype == F_WRLCK) ? LOCK_EX : LOCK_SH;
+  if (flocktime > 0)
+    {
+    ALARM(flocktime);
+    yield = flock(fd, flocktype);
+    save_errno = errno;
+    ALARM_CLR(0);
+    errno = save_errno;
+    }
+  else yield = flock(fd, flocktype | LOCK_NB);
+  }
+#endif  /* NO_FLOCK */
+
+return yield;
+}
+
+
+
+
+#ifdef SUPPORT_MBX
+/*************************************************
+*         Copy message into MBX mailbox          *
+*************************************************/
+
+/* This function is called when a message intended for a MBX mailbox has been
+written to a temporary file. We can now get the size of the message and then
+copy it in MBX format to the mailbox.
+
+Arguments:
+  to_fd        fd to write to (the real mailbox)
+  from_fd      fd to read from (the temporary file)
+  saved_size   current size of mailbox
+
+Returns:       OK if all went well, DEFER otherwise, with errno preserved
+               the number of bytes written are added to transport_count
+                 by virtue of calling transport_write_block()
+*/
+
+/* Values taken from c-client */
+
+#define MBX_HDRSIZE            2048
+#define MBX_NUSERFLAGS           30
+
+static int
+copy_mbx_message(int to_fd, int from_fd, off_t saved_size)
+{
+int used;
+off_t size;
+struct stat statbuf;
+transport_ctx tctx = { .u={.fd = to_fd}, .options = topt_not_socket };
+
+/* If the current mailbox size is zero, write a header block */
+
+if (saved_size == 0)
+  {
+  uschar *s;
+  memset (deliver_out_buffer, '\0', MBX_HDRSIZE);
+  sprintf(CS(s = deliver_out_buffer), "*mbx*\015\012%08lx00000000\015\012",
+    (long int)time(NULL));
+  for (int i = 0; i < MBX_NUSERFLAGS; i++)
+    sprintf (CS(s += Ustrlen(s)), "\015\012");
+  if (!transport_write_block (&tctx, deliver_out_buffer, MBX_HDRSIZE, FALSE))
+    return DEFER;
+  }
+
+DEBUG(D_transport) debug_printf("copying MBX message from temporary file\n");
+
+/* Now construct the message's header from the time and the RFC822 file
+size, including CRLFs, which is the size of the input (temporary) file. */
+
+if (fstat(from_fd, &statbuf) < 0) return DEFER;
+size = statbuf.st_size;
+
+sprintf (CS deliver_out_buffer, "%s," OFF_T_FMT ";%08lx%04x-%08x\015\012",
+  tod_stamp(tod_mbx), size, 0L, 0, 0);
+used = Ustrlen(deliver_out_buffer);
+
+/* Rewind the temporary file, and copy it over in chunks. */
+
+if (lseek(from_fd, 0 , SEEK_SET) < 0) return DEFER;
+
+while (size > 0)
+  {
+  int len = read(from_fd, deliver_out_buffer + used,
+    DELIVER_OUT_BUFFER_SIZE - used);
+  if (len <= 0)
+    {
+    if (len == 0) errno = ERRNO_MBXLENGTH;
+    return DEFER;
+    }
+  if (!transport_write_block(&tctx, deliver_out_buffer, used + len, FALSE))
+    return DEFER;
+  size -= len;
+  used = 0;
+  }
+
+return OK;
+}
+#endif  /* SUPPORT_MBX */
+
+
+
+/*************************************************
+*            Check creation is permitted         *
+*************************************************/
+
+/* This function checks whether a given file name is permitted to be created,
+as controlled by the create_file option. If no home directory is set, however,
+we can't do any tests.
+
+Arguments:
+  filename     the file name
+  create_file  the ob->create_file option
+
+Returns:       TRUE if creation is permitted
+*/
+
+static BOOL
+check_creation(uschar *filename, int create_file)
+{
+BOOL yield = TRUE;
+
+if (deliver_home  &&  create_file != create_anywhere)
+  {
+  int len = Ustrlen(deliver_home);
+  uschar *file = filename;
+
+  while (file[0] == '/' && file[1] == '/') file++;
+  if (Ustrncmp(file, deliver_home, len) != 0 || file[len] != '/' ||
+       ( Ustrchr(file+len+2, '/') != NULL &&
+         (
+         create_file != create_belowhome ||
+         Ustrstr(file+len, "/../") != NULL
+         )
+       )
+     ) yield = FALSE;
+
+  /* If yield is TRUE, the file name starts with the home directory, and does
+  not contain any instances of "/../" in the "belowhome" case. However, it may
+  still contain symbolic links. We can check for this by making use of
+  realpath(), which most Unixes seem to have (but make it possible to cut this
+  out). We can't just use realpath() on the whole file name, because we know
+  the file itself doesn't exist, and intermediate directories may also not
+  exist. What we want to know is the real path of the longest existing part of
+  the path. That must match the home directory's beginning, whichever is the
+  shorter. */
+
+  #ifndef NO_REALPATH
+  if (yield && create_file == create_belowhome)
+    {
+    uschar *next;
+    uschar *rp = NULL;
+    for (uschar * slash = Ustrrchr(file, '/');  /* There is known to be one */
+         !rp && slash > file;			/* Stop if reached beginning */
+         slash = next)
+      {
+      *slash = 0;
+      rp = US realpath(CS file, CS big_buffer);
+      next = Ustrrchr(file, '/');
+      *slash = '/';
+      }
+
+    /* If rp == NULL it means that none of the relevant directories exist.
+    This is not a problem here - it means that no symbolic links can exist,
+    which is all we are worried about. Otherwise, we must compare it
+    against the start of the home directory. However, that may itself
+    contain symbolic links, so we have to "realpath" it as well, if
+    possible. */
+
+    if (rp)
+      {
+      uschar hdbuffer[PATH_MAX+1];
+      uschar *rph = deliver_home;
+      int rlen = Ustrlen(big_buffer);
+
+      if ((rp = US realpath(CS deliver_home, CS hdbuffer)))
+        {
+        rph = hdbuffer;
+        len = Ustrlen(rph);
+        }
+
+      if (rlen > len) rlen = len;
+      if (Ustrncmp(rph, big_buffer, rlen) != 0)
+        {
+        yield = FALSE;
+        DEBUG(D_transport) debug_printf("Real path \"%s\" does not match \"%s\"\n",
+          big_buffer, deliver_home);
+        }
+      }
+    }
+  #endif  /* NO_REALPATH */
+  }
+
+return yield;
+}
+
+
+
+/*************************************************
+*              Main entry point                  *
+*************************************************/
+
+/* See local README for general interface details. This transport always
+returns FALSE, indicating that the status which has been placed in the first
+address should be copied to any other addresses in a batch.
+
+Appendfile delivery is tricky and has led to various security problems in other
+mailers. The logic used here is therefore laid out in some detail. When this
+function is called, we are running in a subprocess which has had its gid and
+uid set to the appropriate values. Therefore, we cannot write directly to the
+exim logs. Any errors must be handled by setting appropriate return codes.
+Note that the default setting for addr->transport_return is DEFER, so it need
+not be set unless some other value is required.
+
+The code below calls geteuid() rather than getuid() to get the current uid
+because in weird configurations not running setuid root there may be a
+difference. In the standard configuration, where setuid() has been used in the
+delivery process, there will be no difference between the uid and the euid.
+
+(1)  If the af_file flag is set, this is a delivery to a file after .forward or
+     alias expansion. Otherwise, there must be a configured file name or
+     directory name.
+
+The following items apply in the case when a file name (as opposed to a
+directory name) is given, that is, when appending to a single file:
+
+(2f) Expand the file name.
+
+(3f) If the file name is /dev/null, return success (optimization).
+
+(4f) If the file_format options is set, open the file for reading, and check
+     that the bytes at the start of the file match one of the given strings.
+     If the check indicates a transport other than the current one should be
+     used, pass control to that other transport. Otherwise continue. An empty
+     or non-existent file matches the current transport. The file is closed
+     after the check.
+
+(5f) If a lock file is required, create it (see extensive separate comments
+     below about the algorithm for doing this). It is important to do this
+     before opening the mailbox if NFS is in use.
+
+(6f) Stat the file, using lstat() rather than stat(), in order to pick up
+     details of any symbolic link.
+
+(7f) If the file already exists:
+
+     Check the owner and group if necessary, and defer if they are wrong.
+
+     If it is a symbolic link AND the allow_symlink option is set (NOT the
+     default), go back to (6f) but this time use stat() instead of lstat().
+
+     If it's not a regular file (or FIFO when permitted), defer delivery.
+
+     Check permissions. If the required permissions are *less* than the
+     existing ones, or supplied by the address (often by the user via filter),
+     chmod() the file. Otherwise, defer.
+
+     Save the inode number.
+
+     Open with O_RDRW + O_APPEND, thus failing if the file has vanished.
+
+     If open fails because the file does not exist, go to (6f); on any other
+     failure, defer.
+
+     Check the inode number hasn't changed - I realize this isn't perfect (an
+     inode can be reused) but it's cheap and will catch some of the races.
+
+     Check it's still a regular file (or FIFO if permitted).
+
+     Check that the owner and permissions haven't changed.
+
+     If file_format is set, check that the file still matches the format for
+     the current transport. If not, defer delivery.
+
+(8f) If file does not exist initially:
+
+     Open with O_WRONLY + O_EXCL + O_CREAT with configured mode, unless we know
+     this is via a symbolic link (only possible if allow_symlinks is set), in
+     which case don't use O_EXCL, as it doesn't work.
+
+     If open fails because the file already exists, go to (6f). To avoid
+     looping for ever in a situation where the file is continuously being
+     created and deleted, all of this happens inside a loop that operates
+     lock_retries times and includes the fcntl and flock locking. If the
+     loop completes without the file getting opened, defer and request
+     freezing, because something really weird is happening.
+
+     If open fails for any other reason, defer for subsequent delivery except
+     when this is a file delivery resulting from an alias or forward expansion
+     and the error is EPERM or ENOENT or EACCES, in which case FAIL as this is
+     most likely a user rather than a configuration error.
+
+(9f) We now have the file checked and open for writing. If so configured, lock
+     it using fcntl, flock, or MBX locking rules. If this fails, close the file
+     and goto (6f), up to lock_retries times, after sleeping for a while. If it
+     still fails, give up and defer delivery.
+
+(10f)Save the access time (for subsequent restoration) and the size of the
+     file, for comsat and for re-setting if delivery fails in the middle -
+     e.g. for quota exceeded.
+
+The following items apply in the case when a directory name is given:
+
+(2d) Create a new file in the directory using a temporary name, by opening for
+     writing and with O_CREAT. If maildir format is being used, the file
+     is created in a temporary subdirectory with a prescribed name. If
+     mailstore format is being used, the envelope file is first created with a
+     temporary name, then the data file.
+
+The following items apply in all cases:
+
+(11) We now have the file open for writing, and locked if it was given as a
+     file name. Write the message and flush the file, unless there is a setting
+     of the local quota option, in which case we can check for its excession
+     without doing any writing.
+
+     In the case of MBX format mailboxes, the message is first written to a
+     temporary file, in order to get its correct length. This is then copied to
+     the real file, preceded by an MBX header.
+
+     If there is a quota error on writing, defer the address. Timeout logic
+     will determine for how long retries are attempted. We restore the mailbox
+     to its original length if it's a single file. There doesn't seem to be a
+     uniform error code for quota excession (it even differs between SunOS4
+     and some versions of SunOS5) so a system-dependent macro called
+     ERRNO_QUOTA is used for it, and the value gets put into errno_quota at
+     compile time.
+
+     For any other error (most commonly disk full), do the same.
+
+The following applies after appending to a file:
+
+(12f)Restore the atime; notify_comsat if required; close the file (which
+     unlocks it if it was locked). Delete the lock file if it exists.
+
+The following applies after writing a unique file in a directory:
+
+(12d)For maildir format, rename the file into the new directory. For mailstore
+     format, rename the envelope file to its correct name. Otherwise, generate
+     a unique name from the directory_file option, and rename to that, possibly
+     trying a few times if the file exists and re-expanding the name gives a
+     different string.
+
+This transport yields FAIL only when a file name is generated by an alias or
+forwarding operation and attempting to open it gives EPERM, ENOENT, or EACCES.
+All other failures return DEFER (in addr->transport_return). */
+
+
+BOOL
+appendfile_transport_entry(
+  transport_instance *tblock,      /* data for this instantiation */
+  address_item *addr)              /* address we are working on */
+{
+appendfile_transport_options_block *ob =
+  (appendfile_transport_options_block *)(tblock->options_block);
+struct stat statbuf;
+uschar *fdname = NULL;
+uschar *filename = NULL;
+uschar *hitchname = NULL;
+uschar *dataname = NULL;
+uschar *lockname = NULL;
+uschar *newname = NULL;
+uschar *nametag = NULL;
+uschar *cr = US"";
+uschar *filecount_msg = US"";
+uschar *path;
+struct utimbuf times;
+struct timeval msg_tv;
+BOOL disable_quota = FALSE;
+BOOL isdirectory = FALSE;
+BOOL isfifo = FALSE;
+BOOL wait_for_tick = FALSE;
+uid_t uid = geteuid();     /* See note above */
+gid_t gid = getegid();
+int mbformat;
+int mode = (addr->mode > 0) ? addr->mode : ob->mode;
+off_t saved_size = -1;
+off_t mailbox_size = ob->mailbox_size_value;
+int mailbox_filecount = ob->mailbox_filecount_value;
+int hd = -1;
+int fd = -1;
+int yield = FAIL;
+int i;
+
+#ifdef SUPPORT_MBX
+int save_fd = 0;
+int mbx_lockfd = -1;
+uschar mbx_lockname[40];
+FILE *temp_file = NULL;
+#endif  /* SUPPORT_MBX */
+
+#ifdef SUPPORT_MAILDIR
+int maildirsize_fd = -1;      /* fd for maildirsize file */
+int maildir_save_errno;
+#endif
+
+
+DEBUG(D_transport) debug_printf("appendfile transport entered\n");
+
+/* An "address_file" or "address_directory" transport is used to deliver to
+files specified via .forward or an alias file. Prior to release 4.20, the
+"file" and "directory" options were ignored in this case. This has been changed
+to allow the redirection data to specify what is in effect a folder, whose
+location is determined by the options on the transport.
+
+Compatibility with the case when neither option is set is retained by forcing a
+value for the file or directory name. A directory delivery is assumed if the
+last character of the path from the router is '/'.
+
+The file path is in the local part of the address, but not in the $local_part
+variable (that holds the parent local part). It is, however, in the
+$address_file variable. Below, we update the local part in the address if it
+changes by expansion, so that the final path ends up in the log. */
+
+if (testflag(addr, af_file) && !ob->filename && !ob->dirname)
+  {
+  fdname = US"$address_file";
+  if (address_file[Ustrlen(address_file)-1] == '/' ||
+      ob->maildir_format ||
+      ob->mailstore_format)
+    isdirectory = TRUE;
+  }
+
+/* Handle (a) an "address file" delivery where "file" or "directory" is
+explicitly set and (b) a non-address_file delivery, where one of "file" or
+"directory" must be set; initialization ensures that they are not both set. */
+
+if (!fdname)
+  {
+  if (!(fdname = ob->filename))
+    {
+    fdname = ob->dirname;
+    isdirectory = TRUE;
+    }
+  if (!fdname)
+    {
+    addr->message = string_sprintf("Mandatory file or directory option "
+      "missing from %s transport", tblock->name);
+    goto ret_panic;
+    }
+  }
+
+/* Maildir and mailstore require a directory */
+
+if ((ob->maildir_format || ob->mailstore_format) && !isdirectory)
+  {
+  addr->message = string_sprintf("mail%s_format requires \"directory\" "
+    "to be specified for the %s transport",
+    ob->maildir_format ? "dir" : "store", tblock->name);
+  goto ret_panic;
+  }
+
+if (!(path = expand_string(fdname)))
+  {
+  addr->message = string_sprintf("Expansion of \"%s\" (file or directory "
+    "name for %s transport) failed: %s", fdname, tblock->name,
+    expand_string_message);
+  goto ret_panic;
+  }
+if (is_tainted(path))
+  {
+  addr->message = string_sprintf("Tainted '%s' (file or directory "
+    "name for %s transport) not permitted", path, tblock->name);
+  goto ret_panic;
+  }
+
+if (path[0] != '/')
+  {
+  addr->message = string_sprintf("appendfile: file or directory name "
+    "\"%s\" is not absolute", path);
+  addr->basic_errno = ERRNO_NOTABSOLUTE;
+  return FALSE;
+  }
+
+/* For a file delivery, make sure the local part in the address(es) is updated
+to the true local part. */
+
+if (testflag(addr, af_file))
+  for (address_item * addr2 = addr; addr2; addr2 = addr2->next)
+    addr2->local_part = string_copy(path);
+
+/* The available mailbox formats depend on whether it is a directory or a file
+delivery. */
+
+if (isdirectory)
+  {
+  mbformat =
+  #ifdef SUPPORT_MAILDIR
+    ob->maildir_format ? mbf_maildir :
+  #endif
+  #ifdef SUPPORT_MAILSTORE
+    ob->mailstore_format ? mbf_mailstore :
+  #endif
+    mbf_smail;
+  }
+else
+  {
+  mbformat =
+  #ifdef SUPPORT_MBX
+    ob->mbx_format ? mbf_mbx :
+  #endif
+    mbf_unix;
+  }
+
+DEBUG(D_transport)
+  {
+  debug_printf("appendfile: mode=%o notify_comsat=%d quota=" OFF_T_FMT
+    "%s%s"
+    " warning=" OFF_T_FMT "%s\n"
+    "  %s=%s format=%s\n  message_prefix=%s\n  message_suffix=%s\n  "
+    "maildir_use_size_file=%s\n",
+    mode, ob->notify_comsat, ob->quota_value,
+    ob->quota_no_check ? " (no_check)" : "",
+    ob->quota_filecount_no_check ? " (no_check_filecount)" : "",
+    ob->quota_warn_threshold_value,
+    ob->quota_warn_threshold_is_percent ? "%" : "",
+    isdirectory ? "directory" : "file",
+    path, mailbox_formats[mbformat],
+    !ob->message_prefix ? US"null" : string_printing(ob->message_prefix),
+    !ob->message_suffix ? US"null" : string_printing(ob->message_suffix),
+    ob->maildir_use_size_file ? "yes" : "no");
+
+  if (!isdirectory) debug_printf("  locking by %s%s%s%s%s\n",
+    ob->use_lockfile ? "lockfile " : "",
+    ob->use_mbx_lock ? "mbx locking (" : "",
+    ob->use_fcntl ? "fcntl " : "",
+    ob->use_flock ? "flock" : "",
+    ob->use_mbx_lock ? ")" : "");
+  }
+
+/* If the -N option is set, can't do any more. */
+
+if (f.dont_deliver)
+  {
+  DEBUG(D_transport)
+    debug_printf("*** delivery by %s transport bypassed by -N option\n",
+      tblock->name);
+  addr->transport_return = OK;
+  return FALSE;
+  }
+
+/* Handle the case of a file name. If the file name is /dev/null, we can save
+ourselves some effort and just give a success return right away. */
+
+if (!isdirectory)
+  {
+  BOOL use_lstat = TRUE;
+  BOOL file_opened = FALSE;
+  BOOL allow_creation_here = TRUE;
+
+  if (Ustrcmp(path, "/dev/null") == 0)
+    {
+    addr->transport_return = OK;
+    return FALSE;
+    }
+
+  /* Set the name of the file to be opened, and the file to which the data
+  is written, and find out if we are permitted to create a non-existent file. */
+
+  dataname = filename = path;
+  allow_creation_here = check_creation(filename, ob->create_file);
+
+  /* If ob->create_directory is set, attempt to create the directories in
+  which this mailbox lives, but only if we are permitted to create the file
+  itself. We know we are dealing with an absolute path, because this was
+  checked above. */
+
+  if (ob->create_directory && allow_creation_here)
+    {
+    uschar *p = Ustrrchr(path, '/');
+    *p = '\0';
+    if (!directory_make(NULL, path, ob->dirmode, FALSE))
+      {
+      addr->basic_errno = errno;
+      addr->message =
+        string_sprintf("failed to create directories for %s: %s", path,
+          strerror(errno));
+      DEBUG(D_transport) debug_printf("%s transport: %s\n", tblock->name, path);
+      return FALSE;
+      }
+    *p = '/';
+    }
+
+  /* If file_format is set we must check that any existing file matches one of
+  the configured formats by checking the bytes it starts with. A match then
+  indicates a specific transport - if it is not this one, pass control to it.
+  Otherwise carry on here. An empty or non-existent file matches the current
+  transport. We don't need to distinguish between non-existence and other open
+  failures because if an existing file fails to open here, it will also fail
+  again later when O_RDWR is used. */
+
+  if (ob->file_format)
+    {
+    int cfd = Uopen(path, O_RDONLY, 0);
+    if (cfd >= 0)
+      {
+      transport_instance *tt = check_file_format(cfd, tblock, addr);
+      (void)close(cfd);
+
+      /* If another transport is indicated, call it and return; if no transport
+      was found, just return - the error data will have been set up.*/
+
+      if (tt != tblock)
+        {
+        if (tt)
+          {
+          set_process_info("delivering %s to %s using %s", message_id,
+            addr->local_part, tt->name);
+          debug_print_string(tt->debug_string);
+          addr->transport = tt;
+          (tt->info->code)(tt, addr);
+          }
+        return FALSE;
+        }
+      }
+    }
+
+  /* The locking of mailbox files is worse than the naming of cats, which is
+  known to be "a difficult matter" (T.S. Eliot) and just as cats must have
+  three different names, so several different styles of locking are used.
+
+  Research in other programs that lock mailboxes shows that there is no
+  universally standard method. Having mailboxes NFS-mounted on the system that
+  is delivering mail is not the best thing, but people do run like this,
+  and so the code must do its best to cope.
+
+  Three different locking mechanisms are supported. The initialization function
+  checks that at least one is configured.
+
+  LOCK FILES
+
+  Unless no_use_lockfile is set, we attempt to build a lock file in a way that
+  will work over NFS. Only after that is done do we actually open the mailbox
+  and apply locks to it (if configured).
+
+  Originally, Exim got the file opened before doing anything about locking.
+  However, a very occasional problem was observed on Solaris 2 when delivering
+  over NFS. It is seems that when a file is opened with O_APPEND, the file size
+  gets remembered at open time. If another process on another host (that's
+  important) has the file open and locked and writes to it and then releases
+  the lock while the first process is waiting to get the lock, the first
+  process may fail to write at the new end point of the file - despite the very
+  definite statement about O_APPEND in the man page for write(). Experiments
+  have reproduced this problem, but I do not know any way of forcing a host to
+  update its attribute cache for an open NFS file. It would be nice if it did
+  so when a lock was taken out, but this does not seem to happen. Anyway, to
+  reduce the risk of this problem happening, we now create the lock file
+  (if configured) *before* opening the mailbox. That will prevent two different
+  Exims opening the file simultaneously. It may not prevent clashes with MUAs,
+  however, but Pine at least seems to operate in the same way.
+
+  Lockfiles should normally be used when NFS is involved, because of the above
+  problem.
+
+  The logic for creating the lock file is:
+
+  . The name of the lock file is <mailbox-name>.lock
+
+  . First, create a "hitching post" name by adding the primary host name,
+    current time and pid to the lock file name. This should be unique.
+
+  . Create the hitching post file using WRONLY + CREAT + EXCL.
+
+  . If that fails EACCES, we assume it means that the user is unable to create
+    files in the mail spool directory. Some installations might operate in this
+    manner, so there is a configuration option to allow this state not to be an
+    error - we proceed to lock using fcntl only, after the file is open.
+
+  . Otherwise, an error causes a deferment of the address.
+
+  . Hard link the hitching post to the lock file name.
+
+  . If the link succeeds, we have successfully created the lock file. Simply
+    close and unlink the hitching post file.
+
+  . If the link does not succeed, proceed as follows:
+
+    o Fstat the hitching post file, and then close and unlink it.
+
+    o Now examine the stat data. If the number of links to the file is exactly
+      2, the linking succeeded but for some reason, e.g. an NFS server crash,
+      the return never made it back, so the link() function gave a failure
+      return.
+
+  . This method allows for the lock file to be created by some other process
+    right up to the moment of the attempt to hard link it, and is also robust
+    against NFS server crash-reboots, which would probably result in timeouts
+    in the middle of link().
+
+  . System crashes may cause lock files to get left lying around, and some means
+    of flushing them is required. The approach of writing a pid (used by smail
+    and by elm) into the file isn't useful when NFS may be in use. Pine uses a
+    timeout, which seems a better approach. Since any program that writes to a
+    mailbox using a lock file should complete its task very quickly, Pine
+    removes lock files that are older than 5 minutes. We allow the value to be
+    configurable on the transport.
+
+  FCNTL LOCKING
+
+  If use_fcntl_lock is set, then Exim gets an exclusive fcntl() lock on the
+  mailbox once it is open. This is done by default with a non-blocking lock.
+  Failures to lock cause retries after a sleep, but only for a certain number
+  of tries. A blocking lock is deliberately not used so that we don't hold the
+  mailbox open. This minimizes the possibility of the NFS problem described
+  under LOCK FILES above, if for some reason NFS deliveries are happening
+  without lock files. However, the use of a non-blocking lock and sleep, though
+  the safest approach, does not give the best performance on very busy systems.
+  A blocking lock plus timeout does better. Therefore Exim has an option to
+  allow it to work this way. If lock_fcntl_timeout is set greater than zero, it
+  enables the use of blocking fcntl() calls.
+
+  FLOCK LOCKING
+
+  If use_flock_lock is set, then Exim gets an exclusive flock() lock in the
+  same manner as for fcntl locking above. No-blocking/timeout is also set as
+  above in lock_flock_timeout. Not all operating systems provide or support
+  flock(). For those that don't (as determined by the definition of LOCK_SH in
+  /usr/include/sys/file.h), use_flock_lock may not be set. For some OS, flock()
+  is implemented (not precisely) on top of fcntl(), which means there's no
+  point in actually using it.
+
+  MBX LOCKING
+
+  If use_mbx_lock is set (this is supported only if SUPPORT_MBX is defined)
+  then the rules used for locking in c-client are used. Exim takes out a shared
+  lock on the mailbox file, and an exclusive lock on the file whose name is
+  /tmp/.<device-number>.<inode-number>. The shared lock on the mailbox stops
+  any other MBX client from getting an exclusive lock on it and expunging it.
+  It also stops any other MBX client from unlinking the /tmp lock when it has
+  finished with it.
+
+  The exclusive lock on the /tmp file prevents any other MBX client from
+  updating the mailbox in any way. When writing is finished, if an exclusive
+  lock on the mailbox can be obtained, indicating there are no current sharers,
+  the /tmp file is unlinked.
+
+  MBX locking can use either fcntl() or flock() locking. If neither
+  use_fcntl_lock or use_flock_lock is set, it defaults to using fcntl() only.
+  The calls for getting these locks are by default non-blocking, as for non-mbx
+  locking, but can be made blocking by setting lock_fcntl_timeout and/or
+  lock_flock_timeout as appropriate.  As MBX delivery doesn't work over NFS, it
+  probably makes sense to set timeouts for any MBX deliveries. */
+
+
+  /* Build a lock file if configured to do so - the existence of a lock
+  file is subsequently checked by looking for a non-negative value of the
+  file descriptor hd - even though the file is no longer open. */
+
+  if (ob->use_lockfile)
+    {
+    /* cf. exim_lock.c */
+    lockname = string_sprintf("%s.lock", filename);
+    hitchname = string_sprintf( "%s.%s.%08x.%08x", lockname, primary_hostname,
+      (unsigned int)(time(NULL)), (unsigned int)getpid());
+
+    DEBUG(D_transport) debug_printf("lock name: %s\nhitch name: %s\n", lockname,
+      hitchname);
+
+    /* Lock file creation retry loop */
+
+    for (i = 0; i < ob->lock_retries; sleep(ob->lock_interval), i++)
+      {
+      int rc;
+
+      hd = Uopen(hitchname, O_WRONLY | O_CREAT | O_EXCL, ob->lockfile_mode);
+      if (hd < 0)
+        {
+        addr->basic_errno = errno;
+        addr->message =
+          string_sprintf("creating lock file hitching post %s "
+            "(euid=%ld egid=%ld)", hitchname, (long int)geteuid(),
+            (long int)getegid());
+        return FALSE;
+        }
+
+      /* Attempt to hitch the hitching post to the lock file. If link()
+      succeeds (the common case, we hope) all is well. Otherwise, fstat the
+      file, and get rid of the hitching post. If the number of links was 2,
+      the link was created, despite the failure of link(). If the hitch was
+      not successful, try again, having unlinked the lock file if it is too
+      old.
+
+      There's a version of Linux (2.0.27) which doesn't update its local cache
+      of the inode after link() by default - which many think is a bug - but
+      if the link succeeds, this code will be OK. It just won't work in the
+      case when link() fails after having actually created the link. The Linux
+      NFS person is fixing this; a temporary patch is available if anyone is
+      sufficiently worried. */
+
+      if ((rc = Ulink(hitchname, lockname)) != 0) fstat(hd, &statbuf);
+      (void)close(hd);
+      Uunlink(hitchname);
+      if (rc != 0 && statbuf.st_nlink != 2)
+        {
+        if (ob->lockfile_timeout > 0 && Ustat(lockname, &statbuf) == 0 &&
+            time(NULL) - statbuf.st_ctime > ob->lockfile_timeout)
+          {
+          DEBUG(D_transport) debug_printf("unlinking timed-out lock file\n");
+          Uunlink(lockname);
+          }
+        DEBUG(D_transport) debug_printf("link of hitching post failed - retrying\n");
+        continue;
+        }
+
+      DEBUG(D_transport) debug_printf("lock file created\n");
+      break;
+      }
+
+    /* Check for too many tries at creating the lock file */
+
+    if (i >= ob->lock_retries)
+      {
+      addr->basic_errno = ERRNO_LOCKFAILED;
+      addr->message = string_sprintf("failed to lock mailbox %s (lock file)",
+        filename);
+      return FALSE;
+      }
+    }
+
+
+  /* We now have to get the file open. First, stat() it and act on existence or
+  non-existence. This is in a loop to handle the case of a file's being created
+  or deleted as we watch, and also to handle retries when the locking fails.
+  Rather than holding the file open while waiting for the fcntl() and/or
+  flock() lock, we close and do the whole thing again. This should be safer,
+  especially for NFS files, which might get altered from other hosts, making
+  their cached sizes incorrect.
+
+  With the default settings, no symlinks are permitted, but there is an option
+  to permit symlinks for those sysadmins that know what they are doing.
+  Shudder. However, insist that the initial symlink is owned by the right user.
+  Thus lstat() is used initially; if a symlink is discovered, the loop is
+  repeated such that stat() is used, to look at the end file. */
+
+  for (i = 0; i < ob->lock_retries; i++)
+    {
+    int sleep_before_retry = TRUE;
+    file_opened = FALSE;
+
+    if ((use_lstat ? Ulstat(filename, &statbuf) : Ustat(filename, &statbuf)) != 0)
+      {
+      /* Let's hope that failure to stat (other than non-existence) is a
+      rare event. */
+
+      if (errno != ENOENT)
+        {
+        addr->basic_errno = errno;
+        addr->message = string_sprintf("attempting to stat mailbox %s",
+          filename);
+        goto RETURN;
+        }
+
+      /* File does not exist. If it is required to pre-exist this state is an
+      error. */
+
+      if (ob->file_must_exist)
+        {
+        addr->basic_errno = errno;
+        addr->message = string_sprintf("mailbox %s does not exist, "
+          "but file_must_exist is set", filename);
+        goto RETURN;
+        }
+
+      /* If not permitted to create this file because it isn't in or below
+      the home directory, generate an error. */
+
+      if (!allow_creation_here)
+        {
+        addr->basic_errno = ERRNO_BADCREATE;
+        addr->message = string_sprintf("mailbox %s does not exist, "
+          "but creation outside the home directory is not permitted",
+          filename);
+        goto RETURN;
+        }
+
+      /* Attempt to create and open the file. If open fails because of
+      pre-existence, go round the loop again. For any other error, defer the
+      address, except for an alias or forward generated file name with EPERM,
+      ENOENT, or EACCES, as those are most likely to be user errors rather
+      than Exim config errors. When a symbolic link is permitted and points
+      to a non-existent file, we get here with use_lstat = FALSE. In this case
+      we mustn't use O_EXCL, since it doesn't work. The file is opened RDRW for
+      consistency and because MBX locking requires it in order to be able to
+      get a shared lock. */
+
+      fd = Uopen(filename, O_RDWR | O_APPEND | O_CREAT |
+        (use_lstat ? O_EXCL : 0), mode);
+      if (fd < 0)
+        {
+        if (errno == EEXIST) continue;
+        addr->basic_errno = errno;
+        addr->message = string_sprintf("while creating mailbox %s",
+          filename);
+        if (testflag(addr, af_file) &&
+            (errno == EPERM || errno == ENOENT || errno == EACCES))
+          addr->transport_return = FAIL;
+        goto RETURN;
+        }
+
+      /* We have successfully created and opened the file. Ensure that the group
+      and the mode are correct. */
+
+      if (exim_chown(filename, uid, gid) || Uchmod(filename, mode))
+        {
+        addr->basic_errno = errno;
+        addr->message = string_sprintf("while setting perms on mailbox %s",
+          filename);
+        addr->transport_return = FAIL;
+        goto RETURN;
+        }
+      }
+
+
+    /* The file already exists. Test its type, ownership, and permissions, and
+    save the inode for checking later. If symlinks are permitted (not the
+    default or recommended state) it may be a symlink that already exists.
+    Check its ownership and then look for the file at the end of the link(s).
+    This at least prevents one user creating a symlink for another user in
+    a sticky directory. */
+
+    else
+      {
+      int oldmode = (int)statbuf.st_mode;
+      ino_t inode = statbuf.st_ino;
+      BOOL islink = (oldmode & S_IFMT) == S_IFLNK;
+
+      isfifo = FALSE;        /* In case things are changing */
+
+      /* Check owner if required - the default. */
+
+      if (ob->check_owner && statbuf.st_uid != uid)
+        {
+        addr->basic_errno = ERRNO_BADUGID;
+        addr->message = string_sprintf("mailbox %s%s has wrong uid "
+          "(%ld != %ld)", filename,
+          islink ? " (symlink)" : "",
+          (long int)(statbuf.st_uid), (long int)uid);
+        goto RETURN;
+        }
+
+      /* Group is checked only if check_group is set. */
+
+      if (ob->check_group && statbuf.st_gid != gid)
+        {
+        addr->basic_errno = ERRNO_BADUGID;
+        addr->message = string_sprintf("mailbox %s%s has wrong gid (%d != %d)",
+          filename, islink ? " (symlink)" : "", statbuf.st_gid, gid);
+        goto RETURN;
+        }
+
+      /* Just in case this is a sticky-bit mail directory, we don't want
+      users to be able to create hard links to other users' files. */
+
+      if (statbuf.st_nlink != 1)
+        {
+        addr->basic_errno = ERRNO_NOTREGULAR;
+        addr->message = string_sprintf("mailbox %s%s has too many links (%lu)",
+          filename, islink ? " (symlink)" : "", (unsigned long)statbuf.st_nlink);
+        goto RETURN;
+
+        }
+
+      /* If symlinks are permitted (not recommended), the lstat() above will
+      have found the symlink. Its ownership has just been checked; go round
+      the loop again, using stat() instead of lstat(). That will never yield a
+      mode of S_IFLNK. */
+
+      if (islink && ob->allow_symlink)
+        {
+        use_lstat = FALSE;
+        i--;                   /* Don't count this time round */
+        continue;
+        }
+
+      /* An actual file exists. Check that it is a regular file, or FIFO
+      if permitted. */
+
+      if (ob->allow_fifo && (oldmode & S_IFMT) == S_IFIFO) isfifo = TRUE;
+
+      else if ((oldmode & S_IFMT) != S_IFREG)
+        {
+        addr->basic_errno = ERRNO_NOTREGULAR;
+        addr->message = string_sprintf("mailbox %s is not a regular file%s",
+          filename, ob->allow_fifo ? " or named pipe" : "");
+        goto RETURN;
+        }
+
+      /* If the mode is not what it would be for a newly created file, change
+      the permissions if the mode is supplied for the address. Otherwise,
+      reduce but do not extend the permissions. If the newly created
+      permissions are greater than the existing permissions, don't change
+      things when the mode is not from the address. */
+
+      if ((oldmode &= 07777) != mode)
+        {
+        int diffs = oldmode ^ mode;
+        if (addr->mode > 0 || (diffs & oldmode) == diffs)
+          {
+          DEBUG(D_transport) debug_printf("chmod %o %s\n", mode, filename);
+          if (Uchmod(filename, mode) < 0)
+            {
+            addr->basic_errno = errno;
+            addr->message = string_sprintf("attempting to chmod mailbox %s",
+              filename);
+            goto RETURN;
+            }
+          oldmode = mode;
+          }
+
+        /* Mode not from address, and newly-created permissions are greater
+        than existing permissions. Default is to complain, but it can be
+        configured to go ahead and try to deliver anyway if that's what
+        the administration wants. */
+
+        else if (ob->mode_fail_narrower)
+          {
+          addr->basic_errno = ERRNO_BADMODE;
+          addr->message = string_sprintf("mailbox %s has the wrong mode %o "
+            "(%o expected)", filename, oldmode, mode);
+          goto RETURN;
+          }
+        }
+
+      /* We are happy with the existing file. Open it, and then do further
+      tests to ensure that it is the same file that we were just looking at.
+      If the file does not now exist, restart this loop, going back to using
+      lstat again. For an NFS error, just defer; other opening errors are
+      more serious. The file is opened RDWR so that its format can be checked,
+      and also MBX locking requires the use of a shared (read) lock. However,
+      a FIFO is opened WRONLY + NDELAY so that it fails if there is no process
+      reading the pipe. */
+
+      fd = Uopen(filename, isfifo ? (O_WRONLY|O_NDELAY) : (O_RDWR|O_APPEND),
+        mode);
+      if (fd < 0)
+        {
+        if (errno == ENOENT)
+          {
+          use_lstat = TRUE;
+          continue;
+          }
+        addr->basic_errno = errno;
+        if (isfifo)
+          addr->message = string_sprintf("while opening named pipe %s "
+            "(could mean no process is reading it)", filename);
+        else if (errno != EWOULDBLOCK)
+          addr->message = string_sprintf("while opening mailbox %s", filename);
+        goto RETURN;
+        }
+
+      /* This fstat really shouldn't fail, as we have an open file! There's a
+      dilemma here. We use fstat in order to be sure we are peering at the file
+      we have got open. However, that won't tell us if the file was reached
+      via a symbolic link. We checked this above, but there is a race exposure
+      if the link was created between the previous lstat and the open. However,
+      it would have to be created with the same inode in order to pass the
+      check below. If ob->allow_symlink is set, causing the use of stat rather
+      than lstat above, symbolic links may be there anyway, and the checking is
+      weaker. */
+
+      if (fstat(fd, &statbuf) < 0)
+        {
+        addr->basic_errno = errno;
+        addr->message = string_sprintf("attempting to stat open mailbox %s",
+          filename);
+        goto RETURN;
+        }
+
+      /* Check the inode; this is isn't a perfect check, but gives some
+      confidence. */
+
+      if (inode != statbuf.st_ino)
+        {
+        addr->basic_errno = ERRNO_INODECHANGED;
+        addr->message = string_sprintf("opened mailbox %s inode number changed "
+          "from " INO_T_FMT " to " INO_T_FMT, filename, inode, statbuf.st_ino);
+        addr->special_action = SPECIAL_FREEZE;
+        goto RETURN;
+        }
+
+      /* Check it's still a regular file or FIFO, and the uid, gid, and
+      permissions have not changed. */
+
+      if ((!isfifo && (statbuf.st_mode & S_IFMT) != S_IFREG) ||
+          (isfifo && (statbuf.st_mode & S_IFMT) != S_IFIFO))
+        {
+        addr->basic_errno = ERRNO_NOTREGULAR;
+        addr->message =
+          string_sprintf("opened mailbox %s is no longer a %s", filename,
+            isfifo ? "named pipe" : "regular file");
+        addr->special_action = SPECIAL_FREEZE;
+        goto RETURN;
+        }
+
+      if ((ob->check_owner && statbuf.st_uid != uid) ||
+          (ob->check_group && statbuf.st_gid != gid))
+        {
+        addr->basic_errno = ERRNO_BADUGID;
+        addr->message =
+          string_sprintf("opened mailbox %s has wrong uid or gid", filename);
+        addr->special_action = SPECIAL_FREEZE;
+        goto RETURN;
+        }
+
+      if ((statbuf.st_mode & 07777) != oldmode)
+        {
+        addr->basic_errno = ERRNO_BADMODE;
+        addr->message = string_sprintf("opened mailbox %s has wrong mode %o "
+          "(%o expected)", filename, statbuf.st_mode & 07777, mode);
+        addr->special_action = SPECIAL_FREEZE;
+        goto RETURN;
+        }
+
+      /* If file_format is set, check that the format of the file has not
+      changed. Error data is set by the testing function. */
+
+      if (ob->file_format  &&  check_file_format(fd, tblock, addr) != tblock)
+        {
+        addr->message = US"open mailbox has changed format";
+        goto RETURN;
+        }
+
+      /* The file is OK. Carry on to do the locking. */
+      }
+
+    /* We now have an open file, and must lock it using fcntl(), flock() or MBX
+    locking rules if configured to do so. If a lock file is also required, it
+    was created above and hd was left >= 0. At least one form of locking is
+    required by the initialization function. If locking fails here, close the
+    file and go round the loop all over again, after waiting for a bit, unless
+    blocking locking was used. */
+
+    file_opened = TRUE;
+    if ((ob->lock_fcntl_timeout > 0) || (ob->lock_flock_timeout > 0))
+      sleep_before_retry = FALSE;
+
+    /* Simple fcntl() and/or flock() locking */
+
+    if (!ob->use_mbx_lock && (ob->use_fcntl || ob->use_flock))
+      {
+      if (apply_lock(fd, F_WRLCK, ob->use_fcntl, ob->lock_fcntl_timeout,
+         ob->use_flock, ob->lock_flock_timeout) >= 0) break;
+      }
+
+    /* MBX locking rules */
+
+    #ifdef SUPPORT_MBX
+    else if (ob->use_mbx_lock)
+      {
+      int mbx_tmp_oflags;
+      struct stat lstatbuf, statbuf2;
+      if (apply_lock(fd, F_RDLCK, ob->use_fcntl, ob->lock_fcntl_timeout,
+           ob->use_flock, ob->lock_flock_timeout) >= 0 &&
+           fstat(fd, &statbuf) >= 0)
+        {
+        sprintf(CS mbx_lockname, "/tmp/.%lx.%lx", (long)statbuf.st_dev,
+          (long)statbuf.st_ino);
+
+        /*
+         * 2010-05-29: SECURITY
+         * Dan Rosenberg reported the presence of a race-condition in the
+         * original code here.  Beware that many systems still allow symlinks
+         * to be followed in /tmp so an attacker can create a symlink pointing
+         * elsewhere between a stat and an open, which we should avoid
+         * following.
+         *
+         * It's unfortunate that we can't just use all the heavily debugged
+         * locking from above.
+         *
+         * Also: remember to mirror changes into exim_lock.c */
+
+        /* first leave the old pre-check in place, it provides better
+         * diagnostics for common cases */
+        if (Ulstat(mbx_lockname, &statbuf) >= 0)
+          {
+          if ((statbuf.st_mode & S_IFMT) == S_IFLNK)
+            {
+            addr->basic_errno = ERRNO_LOCKFAILED;
+            addr->message = string_sprintf("symbolic link on MBX lock file %s",
+              mbx_lockname);
+            goto RETURN;
+            }
+          if (statbuf.st_nlink > 1)
+            {
+            addr->basic_errno = ERRNO_LOCKFAILED;
+            addr->message = string_sprintf("hard link to MBX lock file %s",
+              mbx_lockname);
+            goto RETURN;
+            }
+          }
+
+        /* If we could just declare "we must be the ones who create this
+         * file" then a hitching post in a subdir would work, since a
+         * subdir directly in /tmp/ which we create wouldn't follow links
+         * but this isn't our locking logic, so we can't safely change the
+         * file existence rules. */
+
+        /* On systems which support O_NOFOLLOW, it's the easiest and most
+         * obviously correct security fix */
+        mbx_tmp_oflags = O_RDWR | O_CREAT;
+#ifdef O_NOFOLLOW
+        mbx_tmp_oflags |= O_NOFOLLOW;
+#endif
+        mbx_lockfd = Uopen(mbx_lockname, mbx_tmp_oflags, ob->lockfile_mode);
+        if (mbx_lockfd < 0)
+          {
+          addr->basic_errno = ERRNO_LOCKFAILED;
+          addr->message = string_sprintf("failed to open MBX lock file %s :%s",
+            mbx_lockname, strerror(errno));
+          goto RETURN;
+          }
+
+        if (Ulstat(mbx_lockname, &lstatbuf) < 0)
+          {
+          addr->basic_errno = ERRNO_LOCKFAILED;
+          addr->message = string_sprintf("attempting to lstat open MBX "
+             "lock file %s: %s", mbx_lockname, strerror(errno));
+          goto RETURN;
+          }
+        if (fstat(mbx_lockfd, &statbuf2) < 0)
+          {
+          addr->basic_errno = ERRNO_LOCKFAILED;
+          addr->message = string_sprintf("attempting to stat fd of open MBX "
+              "lock file %s: %s", mbx_lockname, strerror(errno));
+          goto RETURN;
+          }
+
+        /*
+         * At this point:
+         *  statbuf: if exists, is file which existed prior to opening the
+         *           lockfile, might have been replaced since then
+         *  statbuf2: result of stat'ing the open fd, is what was actually
+         *            opened
+         *  lstatbuf: result of lstat'ing the filename immediately after
+         *            the open but there's a race condition again between
+         *            those two steps: before open, symlink to foo, after
+         *            open but before lstat have one of:
+         *             * was no symlink, so is the opened file
+         *               (we created it, no messing possible after that point)
+         *             * hardlink to foo
+         *             * symlink elsewhere
+         *             * hardlink elsewhere
+         *             * new file/other
+         * Don't want to compare to device of /tmp because some modern systems
+         * have regressed to having /tmp be the safe actual filesystem as
+         * valuable data, so is mostly worthless, unless we assume that *only*
+         * Linux systems do this and that all Linux has O_NOFOLLOW.  Something
+         * for further consideration.
+         * No point in doing a readlink on the lockfile as that will always be
+         * at a different point in time from when we open it, so tells us
+         * nothing; attempts to clean up and delete after ourselves would risk
+         * deleting a *third* filename.
+         */
+        if ((statbuf2.st_nlink > 1) ||
+            (lstatbuf.st_nlink > 1) ||
+            (!S_ISREG(lstatbuf.st_mode)) ||
+            (lstatbuf.st_dev != statbuf2.st_dev) ||
+            (lstatbuf.st_ino != statbuf2.st_ino))
+          {
+          addr->basic_errno = ERRNO_LOCKFAILED;
+          addr->message = string_sprintf("RACE CONDITION detected: "
+              "mismatch post-initial-checks between \"%s\" and opened "
+              "fd lead us to abort!", mbx_lockname);
+          goto RETURN;
+          }
+
+        (void)Uchmod(mbx_lockname, ob->lockfile_mode);
+
+        if (apply_lock(mbx_lockfd, F_WRLCK, ob->use_fcntl,
+            ob->lock_fcntl_timeout, ob->use_flock, ob->lock_flock_timeout) >= 0)
+          {
+          struct stat ostatbuf;
+
+          /* This tests for a specific race condition. Ensure that we still
+          have the same file. */
+
+          if (Ulstat(mbx_lockname, &statbuf) == 0 &&
+              fstat(mbx_lockfd, &ostatbuf) == 0 &&
+              statbuf.st_dev == ostatbuf.st_dev &&
+              statbuf.st_ino == ostatbuf.st_ino)
+            break;
+          DEBUG(D_transport) debug_printf("MBX lockfile %s changed "
+            "between creation and locking\n", mbx_lockname);
+          }
+
+        DEBUG(D_transport) debug_printf("failed to lock %s: %s\n", mbx_lockname,
+          strerror(errno));
+        (void)close(mbx_lockfd);
+        mbx_lockfd = -1;
+        }
+      else
+        {
+        DEBUG(D_transport) debug_printf("failed to fstat or get read lock on %s: %s\n",
+          filename, strerror(errno));
+        }
+      }
+    #endif  /* SUPPORT_MBX */
+
+    else break;   /* No on-file locking required; break the open/lock loop */
+
+    DEBUG(D_transport)
+      debug_printf("fcntl(), flock(), or MBX locking failed - retrying\n");
+
+    (void)close(fd);
+    fd = -1;
+    use_lstat = TRUE;             /* Reset to use lstat first */
+
+
+    /* If a blocking call timed out, break the retry loop if the total time
+    so far is not less than than retries * interval. Use the larger of the
+    flock() and fcntl() timeouts. */
+
+    if (sigalrm_seen &&
+        (i+1) * ((ob->lock_fcntl_timeout > ob->lock_flock_timeout)?
+          ob->lock_fcntl_timeout : ob->lock_flock_timeout) >=
+          ob->lock_retries * ob->lock_interval)
+      i = ob->lock_retries;
+
+    /* Wait a bit before retrying, except when it was a blocked fcntl() or
+    flock() that caused the problem. */
+
+    if (i < ob->lock_retries && sleep_before_retry) sleep(ob->lock_interval);
+    }
+
+  /* Test for exceeding the maximum number of tries. Either the file remains
+  locked, or, if we haven't got it open, something is terribly wrong... */
+
+  if (i >= ob->lock_retries)
+    {
+    if (!file_opened)
+      {
+      addr->basic_errno = ERRNO_EXISTRACE;
+      addr->message = string_sprintf("mailbox %s: existence unclear", filename);
+      addr->special_action = SPECIAL_FREEZE;
+      }
+    else
+      {
+      addr->basic_errno = ERRNO_LOCKFAILED;
+      addr->message = string_sprintf("failed to lock mailbox %s (fcntl/flock)",
+        filename);
+      }
+    goto RETURN;
+    }
+
+  DEBUG(D_transport) debug_printf("mailbox %s is locked\n", filename);
+
+  /* Save access time (for subsequent restoration), modification time (for
+  restoration if updating fails), size of file (for comsat and for re-setting if
+  delivery fails in the middle - e.g. for quota exceeded). */
+
+  if (fstat(fd, &statbuf) < 0)
+    {
+    addr->basic_errno = errno;
+    addr->message = string_sprintf("while fstatting opened mailbox %s",
+      filename);
+    goto RETURN;
+    }
+
+  times.actime = statbuf.st_atime;
+  times.modtime = statbuf.st_mtime;
+  saved_size = statbuf.st_size;
+  if (mailbox_size < 0) mailbox_size = saved_size;
+  mailbox_filecount = 0;  /* Not actually relevant for single-file mailbox */
+  }
+
+/* Prepare for writing to a new file (as opposed to appending to an old one).
+There are several different formats, but there is preliminary stuff concerned
+with quotas that applies to all of them. Finding the current size by directory
+scanning is expensive; for maildirs some fudges have been invented:
+
+  (1) A regex can be used to extract a file size from its name;
+  (2) If maildir_use_size is set, a maildirsize file is used to cache the
+      mailbox size.
+*/
+
+else
+  {
+  uschar *check_path = path;    /* Default quota check path */
+  const pcre *regex = NULL;     /* Regex for file size from file name */
+
+  if (!check_creation(string_sprintf("%s/any", path), ob->create_file))
+    {
+    addr->basic_errno = ERRNO_BADCREATE;
+    addr->message = string_sprintf("tried to create file in %s, but "
+      "file creation outside the home directory is not permitted", path);
+    goto RETURN;
+    }
+
+  #ifdef SUPPORT_MAILDIR
+  /* For a maildir delivery, ensure that all the relevant directories exist,
+  and a maildirfolder file if necessary. */
+
+  if (mbformat == mbf_maildir && !maildir_ensure_directories(path, addr,
+    ob->create_directory, ob->dirmode, ob->maildirfolder_create_regex))
+      return FALSE;
+  #endif  /* SUPPORT_MAILDIR */
+
+  /* If we are going to do a quota check, of if maildir_use_size_file is set
+  for a maildir delivery, compile the regular expression if there is one. We
+  may also need to adjust the path that is used. We need to do this for
+  maildir_use_size_file even if the quota is unset, because we still want to
+  create the file. When maildir support is not compiled,
+  ob->maildir_use_size_file is always FALSE. */
+
+  if (ob->quota_value > 0 || THRESHOLD_CHECK || ob->maildir_use_size_file)
+    {
+    const uschar *error;
+    int offset;
+
+    /* Compile the regex if there is one. */
+
+    if (ob->quota_size_regex)
+      {
+      if (!(regex = pcre_compile(CS ob->quota_size_regex, PCRE_COPT,
+	  CCSS &error, &offset, NULL)))
+        {
+        addr->message = string_sprintf("appendfile: regular expression "
+          "error: %s at offset %d while compiling %s", error, offset,
+          ob->quota_size_regex);
+        return FALSE;
+        }
+      DEBUG(D_transport) debug_printf("using regex for file sizes: %s\n",
+        ob->quota_size_regex);
+      }
+
+    /* Use an explicitly configured directory if set */
+
+    if (ob->quota_directory)
+      {
+      if (!(check_path = expand_string(ob->quota_directory)))
+        {
+        addr->message = string_sprintf("Expansion of \"%s\" (quota_directory "
+         "name for %s transport) failed: %s", ob->quota_directory,
+          tblock->name, expand_string_message);
+        goto ret_panic;
+        }
+
+      if (check_path[0] != '/')
+        {
+        addr->message = string_sprintf("appendfile: quota_directory name "
+          "\"%s\" is not absolute", check_path);
+        addr->basic_errno = ERRNO_NOTABSOLUTE;
+        return FALSE;
+        }
+      }
+
+    #ifdef SUPPORT_MAILDIR
+    /* Otherwise, if we are handling a maildir delivery, and the directory
+    contains a file called maildirfolder, this is a maildir++ feature telling
+    us that this is a sub-directory of the real inbox. We should therefore do
+    the quota check on the parent directory. Beware of the special case when
+    the directory name itself ends in a slash. */
+
+    else if (mbformat == mbf_maildir)
+      {
+      struct stat statbuf;
+      if (Ustat(string_sprintf("%s/maildirfolder", path), &statbuf) >= 0)
+        {
+        uschar *new_check_path = string_copy(check_path);
+        uschar *slash = Ustrrchr(new_check_path, '/');
+        if (slash != NULL)
+          {
+          if (slash[1] == 0)
+            {
+            *slash = 0;
+            slash = Ustrrchr(new_check_path, '/');
+            }
+          if (slash != NULL)
+            {
+            *slash = 0;
+            check_path = new_check_path;
+            DEBUG(D_transport) debug_printf("maildirfolder file exists: "
+              "quota check directory changed to %s\n", check_path);
+            }
+          }
+        }
+      }
+    #endif  /* SUPPORT_MAILDIR */
+    }
+
+  /* If we are using maildirsize files, we need to ensure that such a file
+  exists and, if necessary, recalculate its contents. As a byproduct of this,
+  we obtain the current size of the maildir. If no quota is to be enforced
+  (ob->quota_value == 0), we still need the size if a threshold check will
+  happen later.
+
+  Another regular expression is used to determine which directories inside the
+  maildir are going to be counted. */
+
+  #ifdef SUPPORT_MAILDIR
+  if (ob->maildir_use_size_file)
+    {
+    const pcre *dir_regex = NULL;
+    const uschar *error;
+    int offset;
+
+    if (ob->maildir_dir_regex)
+      {
+      int check_path_len = Ustrlen(check_path);
+
+      if (!(dir_regex = pcre_compile(CS ob->maildir_dir_regex, PCRE_COPT,
+	  CCSS &error, &offset, NULL)))
+        {
+        addr->message = string_sprintf("appendfile: regular expression "
+          "error: %s at offset %d while compiling %s", error, offset,
+          ob->maildir_dir_regex);
+        return FALSE;
+        }
+
+      DEBUG(D_transport)
+        debug_printf("using regex for maildir directory selection: %s\n",
+          ob->maildir_dir_regex);
+
+      /* Check to see if we are delivering into an ignored directory, that is,
+      if the delivery path starts with the quota check path, and the rest
+      of the deliver path matches the regex; if so, set a flag to disable quota
+      checking and maildirsize updating. */
+
+      if (Ustrncmp(path, check_path, check_path_len) == 0)
+        {
+        uschar *s = path + check_path_len;
+        while (*s == '/') s++;
+        s = (*s == 0) ? US "new" : string_sprintf("%s/new", s);
+        if (pcre_exec(dir_regex, NULL, CS s, Ustrlen(s), 0, 0, NULL, 0) < 0)
+          {
+          disable_quota = TRUE;
+          DEBUG(D_transport) debug_printf("delivery directory does not match "
+            "maildir_quota_directory_regex: disabling quota\n");
+          }
+        }
+      }
+
+    /* Quota enforcement; create and check the file. There is some discussion
+    about whether this should happen if the quota is unset. At present, Exim
+    always creates the file. If we ever want to change this, uncomment
+    appropriate lines below, possibly doing a check on some option. */
+
+/*  if (???? || ob->quota_value > 0) */
+
+    if (!disable_quota)
+      {
+      off_t size;
+      int filecount;
+
+      if ((maildirsize_fd = maildir_ensure_sizefile(check_path, ob, regex, dir_regex,
+	  &size, &filecount)) == -1)
+        {
+        addr->basic_errno = errno;
+        addr->message = string_sprintf("while opening or reading "
+          "%s/maildirsize", check_path);
+        return FALSE;
+        }
+      /* can also return -2, which means that the file was removed because of
+      raciness; but in this case, the size & filecount will still have been
+      updated. */
+
+      if (mailbox_size < 0) mailbox_size = size;
+      if (mailbox_filecount < 0) mailbox_filecount = filecount;
+      }
+
+    /* No quota enforcement; ensure file does *not* exist; calculate size if
+    needed. */
+
+/*  else
+ *    {
+ *    time_t old_latest;
+ *    (void)unlink(CS string_sprintf("%s/maildirsize", check_path));
+ *    if (THRESHOLD_CHECK)
+ *      mailbox_size = maildir_compute_size(check_path, &mailbox_filecount, &old_latest,
+ *        regex, dir_regex, FALSE);
+ *    }
+*/
+
+    }
+  #endif  /* SUPPORT_MAILDIR */
+
+  /* Otherwise if we are going to do a quota check later on, and the mailbox
+  size is not set, find the current size of the mailbox. Ditto for the file
+  count. Note that ob->quota_filecount_value cannot be set without
+  ob->quota_value being set. */
+
+  if (!disable_quota &&
+      (ob->quota_value > 0 || THRESHOLD_CHECK) &&
+      (mailbox_size < 0 ||
+        (mailbox_filecount < 0 && ob->quota_filecount_value > 0)))
+    {
+    off_t size;
+    int filecount = 0;
+    DEBUG(D_transport)
+      debug_printf("quota checks on directory %s\n", check_path);
+    size = check_dir_size(check_path, &filecount, regex);
+    if (mailbox_size < 0) mailbox_size = size;
+    if (mailbox_filecount < 0) mailbox_filecount = filecount;
+    }
+
+  /* Handle the case of creating a unique file in a given directory (not in
+  maildir or mailstore format - this is how smail did it). A temporary name is
+  used to create the file. Later, when it is written, the name is changed to a
+  unique one. There is no need to lock the file. An attempt is made to create
+  the directory if it does not exist. */
+
+  if (mbformat == mbf_smail)
+    {
+    DEBUG(D_transport)
+      debug_printf("delivering to new file in %s\n", path);
+    filename = dataname =
+      string_sprintf("%s/temp.%d.%s", path, (int)getpid(), primary_hostname);
+    fd = Uopen(filename, O_WRONLY|O_CREAT, mode);
+    if (fd < 0 &&                                 /* failed to open, and */
+        (errno != ENOENT ||                       /* either not non-exist */
+         !ob->create_directory ||                 /* or not allowed to make */
+         !directory_make(NULL, path, ob->dirmode, FALSE) ||  /* or failed to create dir */
+         (fd = Uopen(filename, O_WRONLY|O_CREAT|O_EXCL, mode)) < 0)) /* or then failed to open */
+      {
+      addr->basic_errno = errno;
+      addr->message = string_sprintf("while creating file %s", filename);
+      return FALSE;
+      }
+    }
+
+  #ifdef SUPPORT_MAILDIR
+
+  /* Handle the case of a unique file in maildir format. The file is written to
+  the tmp subdirectory, with a prescribed form of name. */
+
+  else if (mbformat == mbf_maildir)
+    {
+    DEBUG(D_transport)
+      debug_printf("delivering in maildir format in %s\n", path);
+
+    nametag = ob->maildir_tag;
+
+    /* Check that nametag expands successfully; a hard failure causes a panic
+    return. The actual expansion for use happens again later, when
+    $message_size is accurately known. */
+
+    if (nametag && !expand_string(nametag) && !f.expand_string_forcedfail)
+      {
+      addr->message = string_sprintf("Expansion of \"%s\" (maildir_tag "
+        "for %s transport) failed: %s", nametag, tblock->name,
+        expand_string_message);
+      goto ret_panic;
+      }
+
+    /* We ensured the existence of all the relevant directories above. Attempt
+    to open the temporary file a limited number of times. I think this rather
+    scary-looking for statement is actually OK. If open succeeds, the loop is
+    broken; if not, there is a test on the value of i. Get the time again
+    afresh each time round the loop. Its value goes into a variable that is
+    checked at the end, to make sure we don't release this process until the
+    clock has ticked. */
+
+    for (int i = 1;; i++)
+      {
+      uschar *basename;
+
+      (void)gettimeofday(&msg_tv, NULL);
+      basename = string_sprintf(TIME_T_FMT ".H%luP" PID_T_FMT ".%s",
+       	msg_tv.tv_sec, msg_tv.tv_usec, getpid(), primary_hostname);
+
+      filename = dataname = string_sprintf("tmp/%s", basename);
+      newname = string_sprintf("new/%s", basename);
+
+      if (Ustat(filename, &statbuf) == 0)
+        errno = EEXIST;
+      else if (errno == ENOENT)
+        {
+        if ((fd = Uopen(filename, O_WRONLY | O_CREAT | O_EXCL, mode)) >= 0)
+	  break;
+        DEBUG (D_transport) debug_printf ("open failed for %s: %s\n",
+          filename, strerror(errno));
+        }
+
+      /* Too many retries - give up */
+
+      if (i >= ob->maildir_retries)
+        {
+        addr->message = string_sprintf ("failed to open %s (%d tr%s)",
+          filename, i, (i == 1) ? "y" : "ies");
+        addr->basic_errno = errno;
+        if (errno == errno_quota || errno == ENOSPC)
+          addr->user_message = US"mailbox is full";
+        return FALSE;
+        }
+
+      /* Open or stat failed but we haven't tried too many times yet. */
+
+      sleep(2);
+      }
+
+    /* Note that we have to ensure the clock has ticked before leaving */
+
+    wait_for_tick = TRUE;
+
+    /* Why are these here? Put in because they are present in the non-maildir
+    directory case above. */
+
+    if (exim_chown(filename, uid, gid) || Uchmod(filename, mode))
+      {
+      addr->basic_errno = errno;
+      addr->message = string_sprintf("while setting perms on maildir %s",
+        filename);
+      return FALSE;
+      }
+    }
+
+  #endif  /* SUPPORT_MAILDIR */
+
+  #ifdef SUPPORT_MAILSTORE
+
+  /* Handle the case of a unique file in mailstore format. First write the
+  envelope to a temporary file, then open the main file. The unique base name
+  for the files consists of the message id plus the pid of this delivery
+  process. */
+
+  else
+    {
+    FILE *env_file;
+    mailstore_basename = string_sprintf("%s/%s-%s", path, message_id,
+      string_base62((long int)getpid()));
+
+    DEBUG(D_transport)
+      debug_printf("delivering in mailstore format in %s\n", path);
+
+    filename = string_sprintf("%s.tmp", mailstore_basename);
+    newname  = string_sprintf("%s.env", mailstore_basename);
+    dataname = string_sprintf("%s.msg", mailstore_basename);
+
+    fd = Uopen(filename, O_WRONLY|O_CREAT|O_EXCL, mode);
+    if (fd < 0 &&                                 /* failed to open, and */
+        (errno != ENOENT ||                       /* either not non-exist */
+         !ob->create_directory ||                 /* or not allowed to make */
+         !directory_make(NULL, path, ob->dirmode, FALSE) ||  /* or failed to create dir */
+         (fd = Uopen(filename, O_WRONLY|O_CREAT|O_EXCL, mode)) < 0)) /* or then failed to open */
+      {
+      addr->basic_errno = errno;
+      addr->message = string_sprintf("while creating file %s", filename);
+      return FALSE;
+      }
+
+    /* Why are these here? Put in because they are present in the non-maildir
+    directory case above. */
+
+    if (exim_chown(filename, uid, gid) || Uchmod(filename, mode))
+      {
+      addr->basic_errno = errno;
+      addr->message = string_sprintf("while setting perms on file %s",
+        filename);
+      return FALSE;
+      }
+
+    /* Built a C stream from the open file descriptor. */
+
+    if (!(env_file = fdopen(fd, "wb")))
+      {
+      addr->basic_errno = errno;
+      addr->message = string_sprintf("fdopen of %s ("
+        "for %s transport) failed", filename, tblock->name);
+      (void)close(fd);
+      Uunlink(filename);
+      goto ret_panic;
+      }
+
+    /* Write the envelope file, then close it. */
+
+    if (ob->mailstore_prefix)
+      {
+      uschar *s = expand_string(ob->mailstore_prefix);
+      if (!s)
+        {
+        if (!f.expand_string_forcedfail)
+          {
+          addr->message = string_sprintf("Expansion of \"%s\" (mailstore "
+            "prefix for %s transport) failed: %s", ob->mailstore_prefix,
+            tblock->name, expand_string_message);
+          (void)fclose(env_file);
+          Uunlink(filename);
+          goto ret_panic;
+          }
+        }
+      else
+        {
+        int n = Ustrlen(s);
+        fprintf(env_file, "%s", CS s);
+        if (n == 0 || s[n-1] != '\n') fprintf(env_file, "\n");
+        }
+      }
+
+    fprintf(env_file, "%s\n", sender_address);
+
+    for (address_item * taddr = addr; taddr; taddr = taddr->next)
+      fprintf(env_file, "%s@%s\n", taddr->local_part, taddr->domain);
+
+    if (ob->mailstore_suffix)
+      {
+      uschar *s = expand_string(ob->mailstore_suffix);
+      if (!s)
+        {
+        if (!f.expand_string_forcedfail)
+          {
+          addr->message = string_sprintf("Expansion of \"%s\" (mailstore "
+            "suffix for %s transport) failed: %s", ob->mailstore_suffix,
+            tblock->name, expand_string_message);
+          (void)fclose(env_file);
+          Uunlink(filename);
+          goto ret_panic;
+          }
+        }
+      else
+        {
+        int n = Ustrlen(s);
+        fprintf(env_file, "%s", CS s);
+        if (n == 0 || s[n-1] != '\n') fprintf(env_file, "\n");
+        }
+      }
+
+    if (fclose(env_file) != 0)
+      {
+      addr->basic_errno = errno;
+      addr->message = string_sprintf("while closing %s", filename);
+      Uunlink(filename);
+      return FALSE;
+      }
+
+    DEBUG(D_transport) debug_printf("Envelope file %s written\n", filename);
+
+    /* Now open the data file, and ensure that it has the correct ownership and
+    mode. */
+
+    if ((fd = Uopen(dataname, O_WRONLY|O_CREAT|O_EXCL, mode)) < 0)
+      {
+      addr->basic_errno = errno;
+      addr->message = string_sprintf("while creating file %s", dataname);
+      Uunlink(filename);
+      return FALSE;
+      }
+    if (exim_chown(dataname, uid, gid) || Uchmod(dataname, mode))
+      {
+      addr->basic_errno = errno;
+      addr->message = string_sprintf("while setting perms on file %s",
+        dataname);
+      return FALSE;
+      }
+    }
+
+  #endif  /* SUPPORT_MAILSTORE */
+
+
+  /* In all cases of writing to a new file, ensure that the file which is
+  going to be renamed has the correct ownership and mode. */
+
+  if (exim_chown(filename, uid, gid) || Uchmod(filename, mode))
+    {
+    addr->basic_errno = errno;
+    addr->message = string_sprintf("while setting perms on file %s",
+      filename);
+    return FALSE;
+    }
+  }
+
+
+/* At last we can write the message to the file, preceded by any configured
+prefix line, and followed by any configured suffix line. If there are any
+writing errors, we must defer. */
+
+DEBUG(D_transport) debug_printf("writing to file %s\n", dataname);
+
+yield = OK;
+errno = 0;
+
+/* If there is a local quota setting, check that we are not going to exceed it
+with this message if quota_is_inclusive is set; if it is not set, the check
+is for the mailbox already being over quota (i.e. the current message is not
+included in the check). */
+
+if (!disable_quota && ob->quota_value > 0)
+  {
+  DEBUG(D_transport)
+    {
+    debug_printf("Exim quota = " OFF_T_FMT " old size = " OFF_T_FMT
+      " this message = %d (%sincluded)\n",
+      ob->quota_value, mailbox_size, message_size,
+      ob->quota_is_inclusive ? "" : "not ");
+    debug_printf("  file count quota = %d count = %d\n",
+      ob->quota_filecount_value, mailbox_filecount);
+    }
+
+  if (mailbox_size + (ob->quota_is_inclusive ? message_size:0) > ob->quota_value)
+    if (!ob->quota_no_check)
+      {
+      DEBUG(D_transport) debug_printf("mailbox quota exceeded\n");
+      yield = DEFER;
+      errno = ERRNO_EXIMQUOTA;
+      }
+    else
+      DEBUG(D_transport) debug_printf("mailbox quota exceeded but ignored\n");
+
+  if (ob->quota_filecount_value > 0
+           && mailbox_filecount + (ob->quota_is_inclusive ? 1:0) >
+              ob->quota_filecount_value)
+    if (!ob->quota_filecount_no_check)
+      {
+      DEBUG(D_transport) debug_printf("mailbox file count quota exceeded\n");
+      yield = DEFER;
+      errno = ERRNO_EXIMQUOTA;
+      filecount_msg = US" filecount";
+      }
+    else DEBUG(D_transport) if (ob->quota_filecount_no_check)
+      debug_printf("mailbox file count quota exceeded but ignored\n");
+
+  }
+
+/* If we are writing in MBX format, what we actually do is to write the message
+to a temporary file, and then copy it to the real file once we know its size.
+This is the most straightforward way of getting the correct length in the
+separator line. So, what we do here is to save the real file descriptor, and
+replace it with one for a temporary file. The temporary file gets unlinked once
+opened, so that it goes away on closure. */
+
+#ifdef SUPPORT_MBX
+if (yield == OK && ob->mbx_format)
+  {
+  if (!(temp_file = tmpfile()))
+    {
+    addr->basic_errno = errno;
+    addr->message = US"while setting up temporary file";
+    yield = DEFER;
+    goto RETURN;
+    }
+  save_fd = fd;
+  fd = fileno(temp_file);
+  DEBUG(D_transport) debug_printf("writing to temporary file\n");
+  }
+#endif  /* SUPPORT_MBX */
+
+/* Zero the count of bytes written. It is incremented by the transport_xxx()
+functions. */
+
+transport_count = 0;
+transport_newlines = 0;
+
+/* Write any configured prefix text first */
+
+if (yield == OK && ob->message_prefix && *ob->message_prefix)
+  {
+  uschar *prefix = expand_string(ob->message_prefix);
+  if (!prefix)
+    {
+    errno = ERRNO_EXPANDFAIL;
+    addr->transport_return = PANIC;
+    addr->message = string_sprintf("Expansion of \"%s\" (prefix for %s "
+      "transport) failed", ob->message_prefix, tblock->name);
+    yield = DEFER;
+    }
+  else if (!transport_write_string(fd, "%s", prefix)) yield = DEFER;
+  }
+
+/* If the use_bsmtp option is on, we need to write SMTP prefix information. The
+various different values for batching are handled outside; if there is more
+than one address available here, all must be included. If any address is a
+file, use its parent in the RCPT TO. */
+
+if (yield == OK && ob->use_bsmtp)
+  {
+  transport_count = 0;
+  transport_newlines = 0;
+  if (ob->use_crlf) cr = US"\r";
+  if (!transport_write_string(fd, "MAIL FROM:<%s>%s\n", return_path, cr))
+    yield = DEFER;
+  else
+    {
+    transport_newlines++;
+    for (address_item * a = addr; a; a = a->next)
+      {
+      address_item * b = testflag(a, af_pfr) ? a->parent : a;
+      if (!transport_write_string(fd, "RCPT TO:<%s>%s\n",
+        transport_rcpt_address(b, tblock->rcpt_include_affixes), cr))
+          { yield = DEFER; break; }
+      transport_newlines++;
+      }
+    if (yield == OK && !transport_write_string(fd, "DATA%s\n", cr))
+      yield = DEFER;
+    else
+      transport_newlines++;
+    }
+  }
+
+/* Now the message itself. The options for transport_write_message were set up
+at initialization time. */
+
+if (yield == OK)
+  {
+  transport_ctx tctx = {
+    .u = {.fd=fd},
+    .tblock = tblock,
+    .addr = addr,
+    .check_string = ob->check_string,
+    .escape_string = ob->escape_string,
+    .options =  ob->options | topt_not_socket
+  };
+  if (!transport_write_message(&tctx, 0))
+    yield = DEFER;
+  }
+
+/* Now a configured suffix. */
+
+if (yield == OK && ob->message_suffix && *ob->message_suffix)
+  {
+  uschar *suffix = expand_string(ob->message_suffix);
+  if (!suffix)
+    {
+    errno = ERRNO_EXPANDFAIL;
+    addr->transport_return = PANIC;
+    addr->message = string_sprintf("Expansion of \"%s\" (suffix for %s "
+      "transport) failed", ob->message_suffix, tblock->name);
+    yield = DEFER;
+    }
+  else if (!transport_write_string(fd, "%s", suffix)) yield = DEFER;
+  }
+
+/* If batch smtp, write the terminating dot. */
+
+if (yield == OK && ob->use_bsmtp)
+  if (!transport_write_string(fd, ".%s\n", cr)) yield = DEFER;
+  else transport_newlines++;
+
+/* If MBX format is being used, all that writing was to the temporary file.
+However, if there was an earlier failure (Exim quota exceeded, for example),
+the temporary file won't have got opened - and no writing will have been done.
+If writing was OK, we restore the fd, and call a function that copies the
+message in MBX format into the real file. Otherwise use the temporary name in
+any messages. */
+
+#ifdef SUPPORT_MBX
+if (temp_file && ob->mbx_format)
+  {
+  int mbx_save_errno;
+  fd = save_fd;
+
+  if (yield == OK)
+    {
+    transport_count = 0;   /* Reset transport count for actual write */
+    /* No need to reset transport_newlines as we're just using a block copy
+     * routine so the number won't be affected */
+    yield = copy_mbx_message(fd, fileno(temp_file), saved_size);
+    }
+  else if (errno >= 0) dataname = US"temporary file";
+
+  /* Preserve errno while closing the temporary file. */
+
+  mbx_save_errno = errno;
+  (void)fclose(temp_file);
+  errno = mbx_save_errno;
+  }
+#endif  /* SUPPORT_MBX */
+
+/* Force out the remaining data to check for any errors; some OS don't allow
+fsync() to be called for a FIFO. */
+
+if (yield == OK && !isfifo && EXIMfsync(fd) < 0) yield = DEFER;
+
+/* Update message_size and message_linecount to the accurate count of bytes
+written, including added headers. Note; we subtract 1 from message_linecount as
+this variable doesn't count the new line between the header and the body of the
+message. */
+
+message_size = transport_count;
+message_linecount = transport_newlines - 1;
+
+/* If using a maildir++ quota file, add this message's size to it, and
+close the file descriptor, except when the quota has been disabled because we
+are delivering into an uncounted folder. */
+
+#ifdef SUPPORT_MAILDIR
+if (!disable_quota)
+  {
+  if (yield == OK && maildirsize_fd >= 0)
+    maildir_record_length(maildirsize_fd, message_size);
+  maildir_save_errno = errno;    /* Preserve errno while closing the file */
+  if (maildirsize_fd >= 0)
+    (void)close(maildirsize_fd);
+  errno = maildir_save_errno;
+  }
+#endif  /* SUPPORT_MAILDIR */
+
+/* If there is a quota warning threshold and we are have crossed it with this
+message, set the SPECIAL_WARN flag in the address, to cause a warning message
+to be sent. */
+
+if (!disable_quota && THRESHOLD_CHECK)
+  {
+  off_t threshold = ob->quota_warn_threshold_value;
+  if (ob->quota_warn_threshold_is_percent)
+    threshold = (off_t)(((double)ob->quota_value * threshold) / 100);
+  DEBUG(D_transport)
+    debug_printf("quota = " OFF_T_FMT
+      " threshold = " OFF_T_FMT
+      " old size = " OFF_T_FMT
+      " message size = %d\n",
+      ob->quota_value, threshold, mailbox_size,
+      message_size);
+  if (mailbox_size <= threshold && mailbox_size + message_size > threshold)
+    addr->special_action = SPECIAL_WARN;
+
+  /******* You might think that the test ought to be this:
+  *
+  * if (ob->quota_value > 0 && threshold > 0 && mailbox_size > 0 &&
+  *     mailbox_size <= threshold && mailbox_size + message_size > threshold)
+  *
+  * (indeed, I was sent a patch with that in). However, it is possible to
+  * have a warning threshold without actually imposing a quota, and I have
+  * therefore kept Exim backwards compatible.
+  ********/
+
+  }
+
+/* Handle error while writing the file. Control should come here directly after
+the error, with the reason in errno. In the case of expansion failure in prefix
+or suffix, it will be ERRNO_EXPANDFAIL. */
+
+if (yield != OK)
+  {
+  addr->special_action = SPECIAL_NONE;     /* Cancel any quota warning */
+
+  /* Save the error number. If positive, it will ultimately cause a strerror()
+  call to generate some text. */
+
+  addr->basic_errno = errno;
+
+  /* For system or Exim quota excession, or disk full, set more_errno to the
+  time since the file was last read. If delivery was into a directory, the
+  time since last read logic is not relevant, in general. However, for maildir
+  deliveries we can approximate it by looking at the last modified time of the
+  "new" subdirectory. Since Exim won't be adding new messages, a change to the
+  "new" subdirectory implies that an MUA has moved a message from there to the
+  "cur" directory. */
+
+  if (errno == errno_quota || errno == ERRNO_EXIMQUOTA || errno == ENOSPC)
+    {
+    addr->more_errno = 0;
+    if (!isdirectory) addr->more_errno = (int)(time(NULL) - times.actime);
+
+    #ifdef SUPPORT_MAILDIR
+    else if (mbformat == mbf_maildir)
+      {
+      struct stat statbuf;
+      if (Ustat("new", &statbuf) < 0)
+        {
+        DEBUG(D_transport) debug_printf("maildir quota exceeded: "
+          "stat error %d for \"new\": %s\n", errno, strerror(errno));
+        }
+      else   /* Want a repeatable time when in test harness */
+        addr->more_errno = f.running_in_test_harness ? 10 :
+          (int)time(NULL) - statbuf.st_mtime;
+
+      DEBUG(D_transport)
+        debug_printf("maildir: time since \"new\" directory modified = %s\n",
+        readconf_printtime(addr->more_errno));
+      }
+    #endif /* SUPPORT_MAILDIR */
+    }
+
+  /* Handle system quota excession. Add an explanatory phrase for the error
+  message, since some systems don't have special quota-excession errors,
+  and on those that do, "quota" doesn't always mean anything to the user. */
+
+  if (errno == errno_quota)
+    {
+    #ifndef EDQUOT
+    addr->message = string_sprintf("mailbox is full "
+      "(quota exceeded while writing to file %s)", filename);
+    #else
+    addr->message = US"mailbox is full";
+    #endif  /* EDQUOT */
+    addr->user_message = US"mailbox is full";
+    DEBUG(D_transport) debug_printf("System quota exceeded for %s%s%s\n",
+      dataname,
+      isdirectory ? US"" : US": time since file read = ",
+      isdirectory ? US"" : readconf_printtime(addr->more_errno));
+    }
+
+  /* Handle Exim's own quota-imposition */
+
+  else if (errno == ERRNO_EXIMQUOTA)
+    {
+    addr->message = string_sprintf("mailbox is full "
+      "(MTA-imposed%s quota exceeded while writing to %s)", filecount_msg,
+        dataname);
+    addr->user_message = US"mailbox is full";
+    DEBUG(D_transport) debug_printf("Exim%s quota exceeded for %s%s%s\n",
+      filecount_msg, dataname,
+      isdirectory ? US"" : US": time since file read = ",
+      isdirectory ? US"" : readconf_printtime(addr->more_errno));
+    }
+
+  /* Handle a process failure while writing via a filter; the return
+  from child_close() is in more_errno. */
+
+  else if (errno == ERRNO_FILTER_FAIL)
+    {
+    yield = PANIC;
+    addr->message = string_sprintf("transport filter process failed (%d) "
+      "while writing to %s%s", addr->more_errno, dataname,
+      (addr->more_errno == EX_EXECFAILED) ? ": unable to execute command" : "");
+    }
+
+  /* Handle failure to expand header changes */
+
+  else if (errno == ERRNO_CHHEADER_FAIL)
+    {
+    yield = PANIC;
+    addr->message =
+      string_sprintf("failed to expand headers_add or headers_remove while "
+        "writing to %s: %s", dataname, expand_string_message);
+    }
+
+  /* Handle failure to complete writing of a data block */
+
+  else if (errno == ERRNO_WRITEINCOMPLETE)
+    addr->message = string_sprintf("failed to write data block while "
+      "writing to %s", dataname);
+
+  /* Handle length mismatch on MBX copying */
+
+  #ifdef SUPPORT_MBX
+  else if (errno == ERRNO_MBXLENGTH)
+    addr->message = string_sprintf("length mismatch while copying MBX "
+      "temporary file to %s", dataname);
+  #endif  /* SUPPORT_MBX */
+
+  /* For other errors, a general-purpose explanation, if the message is
+  not already set. */
+
+  else if (addr->message == NULL)
+    addr->message = string_sprintf("error while writing to %s", dataname);
+
+  /* For a file, reset the file size to what it was before we started, leaving
+  the last modification time unchanged, so it will get reset also. All systems
+  investigated so far have ftruncate(), whereas not all have the F_FREESP
+  fcntl() call (BSDI & FreeBSD do not). */
+
+  if (!isdirectory && ftruncate(fd, saved_size))
+    DEBUG(D_transport) debug_printf("Error resetting file size\n");
+  }
+
+/* Handle successful writing - we want the modification time to be now for
+appended files. Remove the default backstop error number. For a directory, now
+is the time to rename the file with a unique name. As soon as such a name
+appears it may get used by another process, so we close the file first and
+check that all is well. */
+
+else
+  {
+  times.modtime = time(NULL);
+  addr->basic_errno = 0;
+
+  /* Handle the case of writing to a new file in a directory. This applies
+  to all single-file formats - maildir, mailstore, and "smail format". */
+
+  if (isdirectory)
+    {
+    if (fstat(fd, &statbuf) < 0)
+      {
+      addr->basic_errno = errno;
+      addr->message = string_sprintf("while fstatting opened message file %s",
+        filename);
+      yield = DEFER;
+      }
+
+    else if (close(fd) < 0)
+      {
+      addr->basic_errno = errno;
+      addr->message = string_sprintf("close() error for %s",
+        (ob->mailstore_format) ? dataname : filename);
+      yield = DEFER;
+      }
+
+    /* File is successfully written and closed. Arrange to rename it. For the
+    different kinds of single-file delivery, some games can be played with the
+    name. The message size is by this time set to the accurate value so that
+    its value can be used in expansions. */
+
+    else
+      {
+      uschar *renamename = newname;
+      fd = -1;
+
+      DEBUG(D_transport) debug_printf("renaming temporary file\n");
+
+      /* If there is no rename name set, we are in a non-maildir, non-mailstore
+      situation. The name is built by expanding the directory_file option, and
+      we make the inode number available for use in this. The expansion was
+      checked for syntactic validity above, before we wrote the file.
+
+      We have to be careful here, in case the file name exists. (In the other
+      cases, the names used are constructed to be unique.) The rename()
+      function just replaces an existing file - we don't want that! So instead
+      of calling rename(), we must use link() and unlink().
+
+      In this case, if the link fails because of an existing file, we wait
+      for one second and try the expansion again, to see if it produces a
+      different value. Do this up to 5 times unless the name stops changing.
+      This makes it possible to build values that are based on the time, and
+      still cope with races from multiple simultaneous deliveries. */
+
+      if (!newname)
+        {
+        uschar *renameleaf;
+        uschar *old_renameleaf = US"";
+
+        for (int i = 0; ; sleep(1), i++)
+          {
+          deliver_inode = statbuf.st_ino;
+          renameleaf = expand_string(ob->dirfilename);
+          deliver_inode = 0;
+
+          if (!renameleaf)
+            {
+            addr->transport_return = PANIC;
+            addr->message = string_sprintf("Expansion of \"%s\" "
+              "(directory_file for %s transport) failed: %s",
+              ob->dirfilename, tblock->name, expand_string_message);
+            goto RETURN;
+            }
+
+          renamename = string_sprintf("%s/%s", path, renameleaf);
+          if (Ulink(filename, renamename) < 0)
+            {
+            DEBUG(D_transport) debug_printf("link failed: %s\n",
+              strerror(errno));
+            if (errno != EEXIST || i >= 4 ||
+                Ustrcmp(renameleaf, old_renameleaf) == 0)
+              {
+              addr->basic_errno = errno;
+              addr->message = string_sprintf("while renaming %s as %s",
+                filename, renamename);
+              yield = DEFER;
+              break;
+              }
+            old_renameleaf = renameleaf;
+            DEBUG(D_transport) debug_printf("%s exists - trying again\n",
+              renamename);
+            }
+          else
+            {
+            Uunlink(filename);
+            filename = NULL;
+            break;
+            }
+          }        /* re-expand loop */
+        }          /* not mailstore or maildir */
+
+      /* For maildir and mailstore formats, the new name was created earlier,
+      except that for maildir, there is the possibility of adding a "tag" on
+      the end of the name by expanding the value of nametag. This usually
+      includes a reference to the message size. The expansion of nametag was
+      checked above, before the file was opened. It either succeeded, or
+      provoked a soft failure. So any failure here can be treated as soft.
+      Ignore non-printing characters and / and put a colon at the start if the
+      first character is alphanumeric. */
+
+      else
+        {
+        if (nametag)
+          {
+          uschar *iptr = expand_string(nametag);
+          if (iptr)
+            {
+            uschar *etag = store_get(Ustrlen(iptr) + 2, is_tainted(iptr));
+            uschar *optr = etag;
+            for ( ; *iptr; iptr++)
+              if (mac_isgraph(*iptr) && *iptr != '/')
+                {
+                if (optr == etag && isalnum(*iptr)) *optr++ = ':';
+                *optr++ = *iptr;
+                }
+            *optr = 0;
+            renamename = string_sprintf("%s%s", newname, etag);
+            }
+          }
+
+        /* Do the rename. If the name is too long and a tag exists, try again
+        without the tag. */
+
+        if (Urename(filename, renamename) < 0 &&
+               (nametag == NULL || errno != ENAMETOOLONG ||
+               (renamename = newname, Urename(filename, renamename) < 0)))
+          {
+          addr->basic_errno = errno;
+          addr->message = string_sprintf("while renaming %s as %s",
+            filename, renamename);
+          yield = DEFER;
+          }
+
+        /* Rename succeeded */
+
+        else
+          {
+          DEBUG(D_transport) debug_printf("renamed %s as %s\n", filename,
+            renamename);
+          filename = dataname = NULL;   /* Prevents attempt to unlink at end */
+          }
+        }        /* maildir or mailstore */
+      }          /* successful write + close */
+    }            /* isdirectory */
+  }              /* write success */
+
+
+/* For a file, restore the last access time (atime), and set the modification
+time as required - changed if write succeeded, unchanged if not. */
+
+if (!isdirectory) utime(CS filename, &times);
+
+/* Notify comsat if configured to do so. It only makes sense if the configured
+file is the one that the comsat daemon knows about. */
+
+if (ob->notify_comsat && yield == OK && deliver_localpart)
+  notify_comsat(deliver_localpart, saved_size);
+
+/* Pass back the final return code in the address structure */
+
+DEBUG(D_transport)
+  debug_printf("appendfile yields %d with errno=%d more_errno=%d\n",
+    yield, addr->basic_errno, addr->more_errno);
+
+addr->transport_return = yield;
+
+/* Close the file, which will release the fcntl lock. For a directory write it
+is closed above, except in cases of error which goto RETURN, when we also need
+to remove the original file(s). For MBX locking, if all has gone well, before
+closing the file, see if we can get an exclusive lock on it, in which case we
+can unlink the /tmp lock file before closing it. This is always a non-blocking
+lock; there's no need to wait if we can't get it. If everything has gone right
+but close fails, defer the message. Then unlink the lock file, if present. This
+point in the code is jumped to from a number of places when errors are
+detected, in order to get the file closed and the lock file tidied away. */
+
+RETURN:
+
+#ifdef SUPPORT_MBX
+if (mbx_lockfd >= 0)
+  {
+  if (yield == OK && apply_lock(fd, F_WRLCK, ob->use_fcntl, 0,
+      ob->use_flock, 0) >= 0)
+    {
+    DEBUG(D_transport)
+      debug_printf("unlinking MBX lock file %s\n", mbx_lockname);
+    Uunlink(mbx_lockname);
+    }
+  (void)close(mbx_lockfd);
+  }
+#endif  /* SUPPORT_MBX */
+
+if (fd >= 0 && close(fd) < 0 && yield == OK)
+  {
+  addr->basic_errno = errno;
+  addr->message = string_sprintf("while closing %s", filename);
+  addr->transport_return = DEFER;
+  }
+
+if (hd >= 0) Uunlink(lockname);
+
+/* We get here with isdirectory and filename set only in error situations. */
+
+if (isdirectory && filename)
+  {
+  Uunlink(filename);
+  if (dataname != filename) Uunlink(dataname);
+  }
+
+/* If wait_for_tick is TRUE, we have done a delivery where the uniqueness of a
+file name relies on time + pid. We must not allow the process to finish until
+the clock has move on by at least one microsecond. Usually we expect this
+already to be the case, but machines keep getting faster... */
+
+if (wait_for_tick) exim_wait_tick(&msg_tv, 1);
+
+/* A return of FALSE means that if there was an error, a common error was
+put in the first address of a batch. */
+
+return FALSE;
+
+ret_panic:
+  addr->transport_return = PANIC;
+  return FALSE;
+}
+
+#endif	/*!MACRO_PREDEF*/
+/* End of transport/appendfile.c */
diff --git a/src/transports/appendfile.h b/src/transports/appendfile.h
new file mode 100644
index 0000000..4f0f126
--- /dev/null
+++ b/src/transports/appendfile.h
@@ -0,0 +1,99 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+/* Copyright (c) University of Cambridge 1995 - 2018 */
+/* See the file NOTICE for conditions of use and distribution. */
+
+/* Private structure for the private options. */
+
+typedef struct {
+  uschar *filename;
+  uschar *dirname;
+  uschar *dirfilename;
+  uschar *message_prefix;
+  uschar *message_suffix;
+  uschar *create_file_string;
+  uschar *quota;
+  uschar *quota_directory;
+  uschar *quota_filecount;
+  uschar *quota_size_regex;
+  uschar *quota_warn_threshold;
+  uschar *mailbox_size_string;
+  uschar *mailbox_filecount_string;
+  uschar *expand_maildir_use_size_file;
+  uschar *maildir_dir_regex;
+  uschar *maildir_tag;
+  uschar *maildirfolder_create_regex;
+  uschar *mailstore_prefix;
+  uschar *mailstore_suffix;
+  uschar *check_string;
+  uschar *escape_string;
+  uschar *file_format;
+  off_t quota_value;
+  off_t quota_warn_threshold_value;
+  off_t mailbox_size_value;
+  int   mailbox_filecount_value;
+  int   quota_filecount_value;
+  int   mode;
+  int   dirmode;
+  int   lockfile_mode;
+  int   lockfile_timeout;
+  int   lock_fcntl_timeout;
+  int   lock_flock_timeout;
+  int   lock_retries;
+  int   lock_interval;
+  int   maildir_retries;
+  int   create_file;
+  int   options;
+  BOOL  allow_fifo;
+  BOOL  allow_symlink;
+  BOOL  check_group;
+  BOOL  check_owner;
+  BOOL  create_directory;
+  BOOL  notify_comsat;
+  BOOL  use_lockfile;
+  BOOL  set_use_lockfile;
+  BOOL  use_fcntl;
+  BOOL  set_use_fcntl;
+  BOOL  use_flock;
+  BOOL  set_use_flock;
+  BOOL  use_mbx_lock;
+  BOOL  set_use_mbx_lock;
+  BOOL  use_bsmtp;
+  BOOL  use_crlf;
+  BOOL  file_must_exist;
+  BOOL  mode_fail_narrower;
+  BOOL  maildir_format;
+  BOOL  maildir_use_size_file;
+  BOOL  mailstore_format;
+  BOOL  mbx_format;
+  BOOL  quota_warn_threshold_is_percent;
+  BOOL  quota_is_inclusive;
+  BOOL  quota_no_check;
+  BOOL  quota_filecount_no_check;
+} appendfile_transport_options_block;
+
+/* Restricted creation options */
+
+enum { create_anywhere, create_belowhome, create_inhome };
+
+/* Data for reading the private options. */
+
+extern optionlist appendfile_transport_options[];
+extern int appendfile_transport_options_count;
+
+/* Block containing default values. */
+
+extern appendfile_transport_options_block appendfile_transport_option_defaults;
+
+/* The main and init entry points for the transport */
+
+extern BOOL appendfile_transport_entry(transport_instance *, address_item *);
+extern void appendfile_transport_init(transport_instance *);
+
+/* Function that is shared with tf_maildir.c */
+
+extern off_t  check_dir_size(const uschar *, int *, const pcre *);
+
+/* End of transports/appendfile.h */
diff --git a/src/transports/autoreply.c b/src/transports/autoreply.c
new file mode 100644
index 0000000..865abbf
--- /dev/null
+++ b/src/transports/autoreply.c
@@ -0,0 +1,825 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+/* Copyright (c) University of Cambridge 1995 - 2018 */
+/* Copyright (c) The Exim Maintainers 2020 */
+/* See the file NOTICE for conditions of use and distribution. */
+
+
+#include "../exim.h"
+#include "autoreply.h"
+
+
+
+/* Options specific to the autoreply transport. They must be in alphabetic
+order (note that "_" comes before the lower case letters). Those starting
+with "*" are not settable by the user but are used by the option-reading
+software for alternative value types. Some options are publicly visible and so
+are stored in the driver instance block. These are flagged with opt_public. */
+#define LOFF(field) OPT_OFF(autoreply_transport_options_block, field)
+
+optionlist autoreply_transport_options[] = {
+  { "bcc",               opt_stringptr,	LOFF(bcc) },
+  { "cc",                opt_stringptr,	LOFF(cc) },
+  { "file",              opt_stringptr,	LOFF(file) },
+  { "file_expand",     opt_bool,	LOFF(file_expand) },
+  { "file_optional",     opt_bool,	LOFF(file_optional) },
+  { "from",              opt_stringptr,	LOFF(from) },
+  { "headers",           opt_stringptr,	LOFF(headers) },
+  { "log",               opt_stringptr,	LOFF(logfile) },
+  { "mode",              opt_octint,	LOFF(mode) },
+  { "never_mail",        opt_stringptr,	LOFF(never_mail) },
+  { "once",              opt_stringptr,	LOFF(oncelog) },
+  { "once_file_size",    opt_int,	LOFF(once_file_size) },
+  { "once_repeat",       opt_stringptr,	LOFF(once_repeat) },
+  { "reply_to",          opt_stringptr,	LOFF(reply_to) },
+  { "return_message",    opt_bool,	LOFF(return_message) },
+  { "subject",           opt_stringptr,	LOFF(subject) },
+  { "text",              opt_stringptr,	LOFF(text) },
+  { "to",                opt_stringptr,	LOFF(to) },
+};
+
+/* Size of the options list. An extern variable has to be used so that its
+address can appear in the tables drtables.c. */
+
+int autoreply_transport_options_count =
+  sizeof(autoreply_transport_options)/sizeof(optionlist);
+
+
+#ifdef MACRO_PREDEF
+
+/* Dummy values */
+autoreply_transport_options_block autoreply_transport_option_defaults = {0};
+void autoreply_transport_init(transport_instance *tblock) {}
+BOOL autoreply_transport_entry(transport_instance *tblock, address_item *addr) {return FALSE;}
+
+#else   /*!MACRO_PREDEF*/
+
+
+/* Default private options block for the autoreply transport. */
+
+autoreply_transport_options_block autoreply_transport_option_defaults = {
+  NULL,           /* from */
+  NULL,           /* reply_to */
+  NULL,           /* to */
+  NULL,           /* cc */
+  NULL,           /* bcc */
+  NULL,           /* subject */
+  NULL,           /* headers */
+  NULL,           /* text */
+  NULL,           /* file */
+  NULL,           /* logfile */
+  NULL,           /* oncelog */
+  NULL,           /* once_repeat */
+  NULL,           /* never_mail */
+  0600,           /* mode */
+  0,              /* once_file_size */
+  FALSE,          /* file_expand */
+  FALSE,          /* file_optional */
+  FALSE           /* return message */
+};
+
+
+
+/* Type of text for the checkexpand() function */
+
+enum { cke_text, cke_hdr, cke_file };
+
+
+
+/*************************************************
+*          Initialization entry point            *
+*************************************************/
+
+/* Called for each instance, after its options have been read, to
+enable consistency checks to be done, or anything else that needs
+to be set up. */
+
+void
+autoreply_transport_init(transport_instance *tblock)
+{
+/*
+autoreply_transport_options_block *ob =
+  (autoreply_transport_options_block *)(tblock->options_block);
+*/
+
+/* If a fixed uid field is set, then a gid field must also be set. */
+
+if (tblock->uid_set && !tblock->gid_set && tblock->expand_gid == NULL)
+  log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
+    "user set without group for the %s transport", tblock->name);
+}
+
+
+
+
+/*************************************************
+*          Expand string and check               *
+*************************************************/
+
+/* If the expansion fails, the error is set up in the address. Expanded
+strings must be checked to ensure they contain only printing characters
+and white space. If not, the function fails.
+
+Arguments:
+   s         string to expand
+   addr      address that is being worked on
+   name      transport name, for error text
+   type      type, for checking content:
+               cke_text => no check
+               cke_hdr  => header, allow \n + whitespace
+               cke_file => file name, no non-printers allowed
+
+Returns:     expanded string if expansion succeeds;
+             NULL otherwise
+*/
+
+static uschar *
+checkexpand(uschar *s, address_item *addr, uschar *name, int type)
+{
+uschar *ss = expand_string(s);
+
+if (!ss)
+  {
+  addr->transport_return = FAIL;
+  addr->message = string_sprintf("Expansion of \"%s\" failed in %s transport: "
+    "%s", s, name, expand_string_message);
+  return NULL;
+  }
+
+if (type != cke_text) for (uschar * t = ss; *t != 0; t++)
+  {
+  int c = *t;
+  const uschar * sp;
+  if (mac_isprint(c)) continue;
+  if (type == cke_hdr && c == '\n' && (t[1] == ' ' || t[1] == '\t')) continue;
+  sp = string_printing(s);
+  addr->transport_return = FAIL;
+  addr->message = string_sprintf("Expansion of \"%s\" in %s transport "
+    "contains non-printing character %d", sp, name, c);
+  return NULL;
+  }
+
+return ss;
+}
+
+
+
+
+/*************************************************
+*          Check a header line for never_mail    *
+*************************************************/
+
+/* This is called to check to, cc, and bcc for addresses in the never_mail
+list. Any that are found are removed.
+
+Arguments:
+  listptr     points to the list of addresses
+  never_mail  an address list, already expanded
+
+Returns:      nothing
+*/
+
+static void
+check_never_mail(uschar **listptr, const uschar *never_mail)
+{
+uschar *s = *listptr;
+
+while (*s != 0)
+  {
+  uschar *error, *next;
+  uschar *e = parse_find_address_end(s, FALSE);
+  int terminator = *e;
+  int start, end, domain, rc;
+
+  /* Temporarily terminate the string at the address end while extracting
+  the operative address within. */
+
+  *e = 0;
+  next = parse_extract_address(s, &error, &start, &end, &domain, FALSE);
+  *e = terminator;
+
+  /* If there is some kind of syntax error, just give up on this header
+  line. */
+
+  if (!next) break;
+
+  /* See if the address is on the never_mail list */
+
+  rc = match_address_list(next,         /* address to check */
+                          TRUE,         /* start caseless */
+                          FALSE,        /* don't expand the list */
+                          &never_mail,  /* the list */
+                          NULL,         /* no caching */
+                          -1,           /* no expand setup */
+                          0,            /* separator from list */
+                          NULL);        /* no lookup value return */
+
+  if (rc == OK)                         /* Remove this address */
+    {
+    DEBUG(D_transport)
+      debug_printf("discarding recipient %s (matched never_mail)\n", next);
+    if (terminator == ',') e++;
+    memmove(s, e, Ustrlen(e) + 1);
+    }
+  else                                  /* Skip over this address */
+    {
+    s = e;
+    if (terminator == ',') s++;
+    }
+  }
+
+/* Check to see if we removed the last address, leaving a terminating comma
+that needs to be removed */
+
+s = *listptr + Ustrlen(*listptr);
+while (s > *listptr && (isspace(s[-1]) || s[-1] == ',')) s--;
+*s = 0;
+
+/* Check to see if there any addresses left; if not, set NULL */
+
+s = *listptr;
+while (s != 0 && isspace(*s)) s++;
+if (*s == 0) *listptr = NULL;
+}
+
+
+
+/*************************************************
+*              Main entry point                  *
+*************************************************/
+
+/* See local README for interface details. This transport always returns
+FALSE, indicating that the top address has the status for all - though in fact
+this transport can handle only one address at at time anyway. */
+
+BOOL
+autoreply_transport_entry(
+  transport_instance *tblock,      /* data for this instantiation */
+  address_item *addr)              /* address we are working on */
+{
+int fd, pid, rc;
+int cache_fd = -1;
+int cache_size = 0;
+int add_size = 0;
+EXIM_DB *dbm_file = NULL;
+BOOL file_expand, return_message;
+uschar *from, *reply_to, *to, *cc, *bcc, *subject, *headers, *text, *file;
+uschar *logfile, *oncelog;
+uschar *cache_buff = NULL;
+uschar *cache_time = NULL;
+uschar *message_id = NULL;
+header_line *h;
+time_t now = time(NULL);
+time_t once_repeat_sec = 0;
+FILE *fp;
+FILE *ff = NULL;
+
+autoreply_transport_options_block *ob =
+  (autoreply_transport_options_block *)(tblock->options_block);
+
+DEBUG(D_transport) debug_printf("%s transport entered\n", tblock->name);
+
+/* Set up for the good case */
+
+addr->transport_return = OK;
+addr->basic_errno = 0;
+
+/* If the address is pointing to a reply block, then take all the data
+from that block. It has typically been set up by a mail filter processing
+router. Otherwise, the data must be supplied by this transport, and
+it has to be expanded here. */
+
+if (addr->reply)
+  {
+  DEBUG(D_transport) debug_printf("taking data from address\n");
+  from = addr->reply->from;
+  reply_to = addr->reply->reply_to;
+  to = addr->reply->to;
+  cc = addr->reply->cc;
+  bcc = addr->reply->bcc;
+  subject = addr->reply->subject;
+  headers = addr->reply->headers;
+  text = addr->reply->text;
+  file = addr->reply->file;
+  logfile = addr->reply->logfile;
+  oncelog = addr->reply->oncelog;
+  once_repeat_sec = addr->reply->once_repeat;
+  file_expand = addr->reply->file_expand;
+  expand_forbid = addr->reply->expand_forbid;
+  return_message = addr->reply->return_message;
+  }
+else
+  {
+  uschar *oncerepeat = ob->once_repeat;
+
+  DEBUG(D_transport) debug_printf("taking data from transport\n");
+  from = ob->from;
+  reply_to = ob->reply_to;
+  to = ob->to;
+  cc = ob->cc;
+  bcc = ob->bcc;
+  subject = ob->subject;
+  headers = ob->headers;
+  text = ob->text;
+  file = ob->file;
+  logfile = ob->logfile;
+  oncelog = ob->oncelog;
+  file_expand = ob->file_expand;
+  return_message = ob->return_message;
+
+  if (  from && !(from = checkexpand(from, addr, tblock->name, cke_hdr))
+     || reply_to && !(reply_to = checkexpand(reply_to, addr, tblock->name, cke_hdr))
+     || to && !(to = checkexpand(to, addr, tblock->name, cke_hdr))
+     || cc && !(cc = checkexpand(cc, addr, tblock->name, cke_hdr))
+     || bcc && !(bcc = checkexpand(bcc, addr, tblock->name, cke_hdr))
+     || subject && !(subject = checkexpand(subject, addr, tblock->name, cke_hdr))
+     || headers && !(headers = checkexpand(headers, addr, tblock->name, cke_text))
+     || text && !(text = checkexpand(text, addr, tblock->name, cke_text))
+     || file && !(file = checkexpand(file, addr, tblock->name, cke_file))
+     || logfile && !(logfile = checkexpand(logfile, addr, tblock->name, cke_file))
+     || oncelog && !(oncelog = checkexpand(oncelog, addr, tblock->name, cke_file))
+     || oncerepeat && !(oncerepeat = checkexpand(oncerepeat, addr, tblock->name, cke_file))
+     )
+    return FALSE;
+
+  if (oncerepeat)
+    {
+    once_repeat_sec = readconf_readtime(oncerepeat, 0, FALSE);
+    if (once_repeat_sec < 0)
+      {
+      addr->transport_return = FAIL;
+      addr->message = string_sprintf("Invalid time value \"%s\" for "
+        "\"once_repeat\" in %s transport", oncerepeat, tblock->name);
+      return FALSE;
+      }
+    }
+  }
+
+/* If the never_mail option is set, we have to scan all the recipients and
+remove those that match. */
+
+if (ob->never_mail)
+  {
+  const uschar *never_mail = expand_string(ob->never_mail);
+
+  if (!never_mail)
+    {
+    addr->transport_return = FAIL;
+    addr->message = string_sprintf("Failed to expand \"%s\" for "
+      "\"never_mail\" in %s transport", ob->never_mail, tblock->name);
+    return FALSE;
+    }
+
+  if (to) check_never_mail(&to, never_mail);
+  if (cc) check_never_mail(&cc, never_mail);
+  if (bcc) check_never_mail(&bcc, never_mail);
+
+  if (!to && !cc && !bcc)
+    {
+    DEBUG(D_transport)
+      debug_printf("*** all recipients removed by never_mail\n");
+    return OK;
+    }
+  }
+
+/* If the -N option is set, can't do any more. */
+
+if (f.dont_deliver)
+  {
+  DEBUG(D_transport)
+    debug_printf("*** delivery by %s transport bypassed by -N option\n",
+      tblock->name);
+  return FALSE;
+  }
+
+
+/* If the oncelog field is set, we send want to send only one message to the
+given recipient(s). This works only on the "To" field. If there is no "To"
+field, the message is always sent. If the To: field contains more than one
+recipient, the effect might not be quite as envisaged. If once_file_size is
+set, instead of a dbm file, we use a regular file containing a circular buffer
+recipient cache. */
+
+if (oncelog && *oncelog && to)
+  {
+  time_t then = 0;
+
+  if (is_tainted(oncelog))
+    {
+    addr->transport_return = DEFER;
+    addr->basic_errno = EACCES;
+    addr->message = string_sprintf("Tainted '%s' (once file for %s transport)"
+      " not permitted", oncelog, tblock->name);
+    goto END_OFF;
+    }
+
+  /* Handle fixed-size cache file. */
+
+  if (ob->once_file_size > 0)
+    {
+    uschar * nextp;
+    struct stat statbuf;
+
+    cache_fd = Uopen(oncelog, O_CREAT|O_RDWR, ob->mode);
+    if (cache_fd < 0 || fstat(cache_fd, &statbuf) != 0)
+      {
+      addr->transport_return = DEFER;
+      addr->basic_errno = errno;
+      addr->message = string_sprintf("Failed to %s \"once\" file %s when "
+        "sending message from %s transport: %s",
+        cache_fd < 0 ? "open" : "stat", oncelog, tblock->name, strerror(errno));
+      goto END_OFF;
+      }
+
+    /* Get store in the temporary pool and read the entire file into it. We get
+    an amount of store that is big enough to add the new entry on the end if we
+    need to do that. */
+
+    cache_size = statbuf.st_size;
+    add_size = sizeof(time_t) + Ustrlen(to) + 1;
+    cache_buff = store_get(cache_size + add_size, is_tainted(oncelog));
+
+    if (read(cache_fd, cache_buff, cache_size) != cache_size)
+      {
+      addr->transport_return = DEFER;
+      addr->basic_errno = errno;
+      addr->message = US"error while reading \"once\" file";
+      goto END_OFF;
+      }
+
+    DEBUG(D_transport) debug_printf("%d bytes read from %s\n", cache_size, oncelog);
+
+    /* Scan the data for this recipient. Each entry in the file starts with
+    a time_t sized time value, followed by the address, followed by a binary
+    zero. If we find a match, put the time into "then", and the place where it
+    was found into "cache_time". Otherwise, "then" is left at zero. */
+
+    for (uschar * p = cache_buff; p < cache_buff + cache_size; p = nextp)
+      {
+      uschar *s = p + sizeof(time_t);
+      nextp = s + Ustrlen(s) + 1;
+      if (Ustrcmp(to, s) == 0)
+        {
+        memcpy(&then, p, sizeof(time_t));
+        cache_time = p;
+        break;
+        }
+      }
+    }
+
+  /* Use a DBM file for the list of previous recipients. */
+
+  else
+    {
+    EXIM_DATUM key_datum, result_datum;
+    uschar * dirname, * s;
+
+    dirname = (s = Ustrrchr(oncelog, '/'))
+      ? string_copyn(oncelog, s - oncelog) : NULL;
+    EXIM_DBOPEN(oncelog, dirname, O_RDWR|O_CREAT, ob->mode, &dbm_file);
+    if (!dbm_file)
+      {
+      addr->transport_return = DEFER;
+      addr->basic_errno = errno;
+      addr->message = string_sprintf("Failed to open %s file %s when sending "
+        "message from %s transport: %s", EXIM_DBTYPE, oncelog, tblock->name,
+        strerror(errno));
+      goto END_OFF;
+      }
+
+    EXIM_DATUM_INIT(key_datum);        /* Some DBM libraries need datums */
+    EXIM_DATUM_INIT(result_datum);     /* to be cleared */
+    EXIM_DATUM_DATA(key_datum) = CS to;
+    EXIM_DATUM_SIZE(key_datum) = Ustrlen(to) + 1;
+
+    if (EXIM_DBGET(dbm_file, key_datum, result_datum))
+      {
+      /* If the datum size is that of a binary time, we are in the new world
+      where messages are sent periodically. Otherwise the file is an old one,
+      where the datum was filled with a tod_log time, which is assumed to be
+      different in size. For that, only one message is ever sent. This change
+      introduced at Exim 3.00. In a couple of years' time the test on the size
+      can be abolished. */
+
+      if (EXIM_DATUM_SIZE(result_datum) == sizeof(time_t))
+        memcpy(&then, EXIM_DATUM_DATA(result_datum), sizeof(time_t));
+      else
+        then = now;
+      }
+    }
+
+  /* Either "then" is set zero, if no message has yet been sent, or it
+  is set to the time of the last sending. */
+
+  if (then != 0 && (once_repeat_sec <= 0 || now - then < once_repeat_sec))
+    {
+    int log_fd;
+    if (is_tainted(logfile))
+      {
+      addr->transport_return = DEFER;
+      addr->basic_errno = EACCES;
+      addr->message = string_sprintf("Tainted '%s' (logfile for %s transport)"
+	" not permitted", logfile, tblock->name);
+      goto END_OFF;
+      }
+
+    DEBUG(D_transport) debug_printf("message previously sent to %s%s\n", to,
+      (once_repeat_sec > 0)? " and repeat time not reached" : "");
+    log_fd = logfile ? Uopen(logfile, O_WRONLY|O_APPEND|O_CREAT, ob->mode) : -1;
+    if (log_fd >= 0)
+      {
+      uschar *ptr = log_buffer;
+      sprintf(CS ptr, "%s\n  previously sent to %.200s\n", tod_stamp(tod_log), to);
+      while(*ptr) ptr++;
+      if(write(log_fd, log_buffer, ptr - log_buffer) != ptr-log_buffer
+        || close(log_fd))
+        DEBUG(D_transport) debug_printf("Problem writing log file %s for %s "
+          "transport\n", logfile, tblock->name);
+      }
+    goto END_OFF;
+    }
+
+  DEBUG(D_transport) debug_printf("%s %s\n", (then <= 0)?
+    "no previous message sent to" : "repeat time reached for", to);
+  }
+
+/* We are going to send a message. Ensure any requested file is available. */
+if (file)
+  {
+  if (is_tainted(file))
+    {
+    addr->transport_return = DEFER;
+    addr->basic_errno = EACCES;
+    addr->message = string_sprintf("Tainted '%s' (file for %s transport)"
+      " not permitted", file, tblock->name);
+    return FALSE;
+    }
+  if (!(ff = Ufopen(file, "rb")) && !ob->file_optional)
+    {
+    addr->transport_return = DEFER;
+    addr->basic_errno = errno;
+    addr->message = string_sprintf("Failed to open file %s when sending "
+      "message from %s transport: %s", file, tblock->name, strerror(errno));
+    return FALSE;
+    }
+  }
+
+/* Make a subprocess to send the message */
+
+if ((pid = child_open_exim(&fd, US"autoreply")) < 0)
+  {
+  /* Creation of child failed; defer this delivery. */
+
+  addr->transport_return = DEFER;
+  addr->basic_errno = errno;
+  addr->message = string_sprintf("Failed to create child process to send "
+    "message from %s transport: %s", tblock->name, strerror(errno));
+  DEBUG(D_transport) debug_printf("%s\n", addr->message);
+  if (dbm_file) EXIM_DBCLOSE(dbm_file);
+  return FALSE;
+  }
+
+/* Create the message to be sent - recipients are taken from the headers,
+as the -t option is used. The "headers" stuff *must* be last in case there
+are newlines in it which might, if placed earlier, screw up other headers. */
+
+fp = fdopen(fd, "wb");
+
+if (from) fprintf(fp, "From: %s\n", from);
+if (reply_to) fprintf(fp, "Reply-To: %s\n", reply_to);
+if (to) fprintf(fp, "To: %s\n", to);
+if (cc) fprintf(fp, "Cc: %s\n", cc);
+if (bcc) fprintf(fp, "Bcc: %s\n", bcc);
+if (subject) fprintf(fp, "Subject: %s\n", subject);
+
+/* Generate In-Reply-To from the message_id header; there should
+always be one, but code defensively. */
+
+for (h = header_list; h; h = h->next)
+  if (h->type == htype_id) break;
+
+if (h)
+  {
+  message_id = Ustrchr(h->text, ':') + 1;
+  while (isspace(*message_id)) message_id++;
+  fprintf(fp, "In-Reply-To: %s", message_id);
+  }
+
+moan_write_references(fp, message_id);
+
+/* Add an Auto-Submitted: header */
+
+fprintf(fp, "Auto-Submitted: auto-replied\n");
+
+/* Add any specially requested headers */
+
+if (headers) fprintf(fp, "%s\n", headers);
+fprintf(fp, "\n");
+
+if (text)
+  {
+  fprintf(fp, "%s", CS text);
+  if (text[Ustrlen(text)-1] != '\n') fprintf(fp, "\n");
+  }
+
+if (ff)
+  {
+  while (Ufgets(big_buffer, big_buffer_size, ff) != NULL)
+    {
+    if (file_expand)
+      {
+      uschar *s = expand_string(big_buffer);
+      DEBUG(D_transport)
+        {
+        if (!s)
+          debug_printf("error while expanding line from file:\n  %s\n  %s\n",
+            big_buffer, expand_string_message);
+        }
+      fprintf(fp, "%s", s ? CS s : CS big_buffer);
+      }
+    else fprintf(fp, "%s", CS big_buffer);
+    }
+  (void) fclose(ff);
+  }
+
+/* Copy the original message if required, observing the return size
+limit if we are returning the body. */
+
+if (return_message)
+  {
+  uschar *rubric = (tblock->headers_only)?
+    US"------ This is a copy of the message's header lines.\n"
+    : (tblock->body_only)?
+    US"------ This is a copy of the body of the message, without the headers.\n"
+    :
+    US"------ This is a copy of the message, including all the headers.\n";
+  transport_ctx tctx = {
+    .u = {.fd = fileno(fp)},
+    .tblock = tblock,
+    .addr = addr,
+    .check_string = NULL,
+    .escape_string =  NULL,
+    .options = (tblock->body_only ? topt_no_headers : 0)
+    	| (tblock->headers_only ? topt_no_body : 0)
+    	| (tblock->return_path_add ? topt_add_return_path : 0)
+    	| (tblock->delivery_date_add ? topt_add_delivery_date : 0)
+    	| (tblock->envelope_to_add ? topt_add_envelope_to : 0)
+	| topt_not_socket
+  };
+
+  if (bounce_return_size_limit > 0 && !tblock->headers_only)
+    {
+    struct stat statbuf;
+    int max = (bounce_return_size_limit/DELIVER_IN_BUFFER_SIZE + 1) *
+      DELIVER_IN_BUFFER_SIZE;
+    if (fstat(deliver_datafile, &statbuf) == 0 && statbuf.st_size > max)
+      {
+      fprintf(fp, "\n%s"
+"------ The body of the message is " OFF_T_FMT " characters long; only the first\n"
+"------ %d or so are included here.\n\n", rubric, statbuf.st_size,
+        (max/1000)*1000);
+      }
+    else fprintf(fp, "\n%s\n", rubric);
+    }
+  else fprintf(fp, "\n%s\n", rubric);
+
+  fflush(fp);
+  transport_count = 0;
+  transport_write_message(&tctx, bounce_return_size_limit);
+  }
+
+/* End the message and wait for the child process to end; no timeout. */
+
+(void)fclose(fp);
+rc = child_close(pid, 0);
+
+/* Update the "sent to" log whatever the yield. This errs on the side of
+missing out a message rather than risking sending more than one. We either have
+cache_fd set to a fixed size, circular buffer file, or dbm_file set to an open
+DBM file (or neither, if "once" is not set). */
+
+/* Update fixed-size cache file. If cache_time is set, we found a previous
+entry; that is the spot into which to put the current time. Otherwise we have
+to add a new record; remove the first one in the file if the file is too big.
+We always rewrite the entire file in a single write operation. This is
+(hopefully) going to be the safest thing because there is no interlocking
+between multiple simultaneous deliveries. */
+
+if (cache_fd >= 0)
+  {
+  uschar *from = cache_buff;
+  int size = cache_size;
+
+  if (lseek(cache_fd, 0, SEEK_SET) == 0)
+    {
+    if (!cache_time)
+      {
+      cache_time = from + size;
+      memcpy(cache_time + sizeof(time_t), to, add_size - sizeof(time_t));
+      size += add_size;
+
+      if (cache_size > 0 && size > ob->once_file_size)
+	{
+	from += sizeof(time_t) + Ustrlen(from + sizeof(time_t)) + 1;
+	size -= (from - cache_buff);
+	}
+      }
+
+    memcpy(cache_time, &now, sizeof(time_t));
+    if(write(cache_fd, from, size) != size)
+      DEBUG(D_transport) debug_printf("Problem writing cache file %s for %s "
+	"transport\n", oncelog, tblock->name);
+    }
+  }
+
+/* Update DBM file */
+
+else if (dbm_file)
+  {
+  EXIM_DATUM key_datum, value_datum;
+  EXIM_DATUM_INIT(key_datum);          /* Some DBM libraries need to have */
+  EXIM_DATUM_INIT(value_datum);        /* cleared datums. */
+  EXIM_DATUM_DATA(key_datum) = CS to;
+  EXIM_DATUM_SIZE(key_datum) = Ustrlen(to) + 1;
+
+  /* Many OS define the datum value, sensibly, as a void *. However, there
+  are some which still have char *. By casting this address to a char * we
+  can avoid warning messages from the char * systems. */
+
+  EXIM_DATUM_DATA(value_datum) = CS (&now);
+  EXIM_DATUM_SIZE(value_datum) = (int)sizeof(time_t);
+  EXIM_DBPUT(dbm_file, key_datum, value_datum);
+  }
+
+/* If sending failed, defer to try again - but if once is set the next
+try will skip, of course. However, if there were no recipients in the
+message, we do not fail. */
+
+if (rc != 0)
+  if (rc == EXIT_NORECIPIENTS)
+    {
+    DEBUG(D_any) debug_printf("%s transport: message contained no recipients\n",
+      tblock->name);
+    }
+  else
+    {
+    addr->transport_return = DEFER;
+    addr->message = string_sprintf("Failed to send message from %s "
+      "transport (%d)", tblock->name, rc);
+    goto END_OFF;
+    }
+
+/* Log the sending of the message if successful and required. If the file
+fails to open, it's hard to know what to do. We cannot write to the Exim
+log from here, since we may be running under an unprivileged uid. We don't
+want to fail the delivery, since the message has been successfully sent. For
+the moment, ignore open failures. Write the log entry as a single write() to a
+file opened for appending, in order to avoid interleaving of output from
+different processes. The log_buffer can be used exactly as for main log
+writing. */
+
+if (logfile)
+  {
+  int log_fd = Uopen(logfile, O_WRONLY|O_APPEND|O_CREAT, ob->mode);
+  if (log_fd >= 0)
+    {
+    gstring gs = { .size = LOG_BUFFER_SIZE, .ptr = 0, .s = log_buffer }, *g = &gs;
+
+    /* Use taint-unchecked routines for writing into log_buffer, trusting
+    that we'll never expand it. */
+
+    DEBUG(D_transport) debug_printf("logging message details\n");
+    g = string_fmt_append_f(g, SVFMT_TAINT_NOCHK, "%s\n", tod_stamp(tod_log));
+    if (from)
+      g = string_fmt_append_f(g, SVFMT_TAINT_NOCHK, "  From: %s\n", from);
+    if (to)
+      g = string_fmt_append_f(g, SVFMT_TAINT_NOCHK, "  To: %s\n", to);
+    if (cc)
+      g = string_fmt_append_f(g, SVFMT_TAINT_NOCHK, "  Cc: %s\n", cc);
+    if (bcc)
+      g = string_fmt_append_f(g, SVFMT_TAINT_NOCHK, "  Bcc: %s\n", bcc);
+    if (subject)
+      g = string_fmt_append_f(g, SVFMT_TAINT_NOCHK, "  Subject: %s\n", subject);
+    if (headers)
+      g = string_fmt_append_f(g, SVFMT_TAINT_NOCHK, "  %s\n", headers);
+    if(write(log_fd, g->s, g->ptr) != g->ptr || close(log_fd))
+      DEBUG(D_transport) debug_printf("Problem writing log file %s for %s "
+        "transport\n", logfile, tblock->name);
+    }
+  else DEBUG(D_transport) debug_printf("Failed to open log file %s for %s "
+    "transport: %s\n", logfile, tblock->name, strerror(errno));
+  }
+
+END_OFF:
+if (dbm_file) EXIM_DBCLOSE(dbm_file);
+if (cache_fd > 0) (void)close(cache_fd);
+
+DEBUG(D_transport) debug_printf("%s transport succeeded\n", tblock->name);
+
+return FALSE;
+}
+
+#endif	/*!MACRO_PREDEF*/
+/* End of transport/autoreply.c */
diff --git a/src/transports/autoreply.h b/src/transports/autoreply.h
new file mode 100644
index 0000000..fcfd981
--- /dev/null
+++ b/src/transports/autoreply.h
@@ -0,0 +1,45 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+/* Copyright (c) University of Cambridge 1995 - 2009 */
+/* See the file NOTICE for conditions of use and distribution. */
+
+/* Private structure for the private options. */
+
+typedef struct {
+  uschar *from;
+  uschar *reply_to;
+  uschar *to;
+  uschar *cc;
+  uschar *bcc;
+  uschar *subject;
+  uschar *headers;
+  uschar *text;
+  uschar *file;
+  uschar *logfile;
+  uschar *oncelog;
+  uschar *once_repeat;
+  uschar *never_mail;
+  int   mode;
+  off_t once_file_size;
+  BOOL  file_expand;
+  BOOL  file_optional;
+  BOOL  return_message;
+} autoreply_transport_options_block;
+
+/* Data for reading the private options. */
+
+extern optionlist autoreply_transport_options[];
+extern int autoreply_transport_options_count;
+
+/* Block containing default values. */
+
+extern autoreply_transport_options_block autoreply_transport_option_defaults;
+
+/* The main and init entry points for the transport */
+
+extern BOOL autoreply_transport_entry(transport_instance *, address_item *);
+extern void autoreply_transport_init(transport_instance *);
+
+/* End of transports/autoreply.h */
diff --git a/src/transports/lmtp.c b/src/transports/lmtp.c
new file mode 100644
index 0000000..5a1b7c9
--- /dev/null
+++ b/src/transports/lmtp.c
@@ -0,0 +1,809 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+/* Copyright (c) University of Cambridge 1995 - 2018 */
+/* Copyright (c) The Exim Maintainers 2020 */
+/* See the file NOTICE for conditions of use and distribution. */
+
+
+#include "../exim.h"
+#include "lmtp.h"
+
+#define PENDING_OK 256
+
+
+/* Options specific to the lmtp transport. They must be in alphabetic
+order (note that "_" comes before the lower case letters). Those starting
+with "*" are not settable by the user but are used by the option-reading
+software for alternative value types. Some options are stored in the transport
+instance block so as to be publicly visible; these are flagged with opt_public.
+*/
+
+optionlist lmtp_transport_options[] = {
+  { "batch_id",          opt_stringptr | opt_public,
+      OPT_OFF(transport_instance, batch_id) },
+  { "batch_max",         opt_int | opt_public,
+      OPT_OFF(transport_instance, batch_max) },
+  { "command",           opt_stringptr,
+      OPT_OFF(lmtp_transport_options_block, cmd) },
+  { "ignore_quota",      opt_bool,
+      OPT_OFF(lmtp_transport_options_block, ignore_quota) },
+  { "socket",            opt_stringptr,
+      OPT_OFF(lmtp_transport_options_block, skt) },
+  { "timeout",           opt_time,
+      OPT_OFF(lmtp_transport_options_block, timeout) }
+};
+
+/* Size of the options list. An extern variable has to be used so that its
+address can appear in the tables drtables.c. */
+
+int lmtp_transport_options_count =
+  sizeof(lmtp_transport_options)/sizeof(optionlist);
+
+
+#ifdef MACRO_PREDEF
+
+/* Dummy values */
+lmtp_transport_options_block lmtp_transport_option_defaults = {0};
+void lmtp_transport_init(transport_instance *tblock) {}
+BOOL lmtp_transport_entry(transport_instance *tblock, address_item *addr) {return FALSE;}
+
+#else   /*!MACRO_PREDEF*/
+
+
+/* Default private options block for the lmtp transport. */
+
+lmtp_transport_options_block lmtp_transport_option_defaults = {
+  NULL,           /* cmd */
+  NULL,           /* skt */
+  5*60,           /* timeout */
+  0,              /* options */
+  FALSE           /* ignore_quota */
+};
+
+
+
+/*************************************************
+*          Initialization entry point            *
+*************************************************/
+
+/* Called for each instance, after its options have been read, to
+enable consistency checks to be done, or anything else that needs
+to be set up. */
+
+void
+lmtp_transport_init(transport_instance *tblock)
+{
+lmtp_transport_options_block *ob =
+  (lmtp_transport_options_block *)(tblock->options_block);
+
+/* Either the command field or the socket field must be set */
+
+if ((ob->cmd == NULL) == (ob->skt == NULL))
+  log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
+    "one (and only one) of command or socket must be set for the %s transport",
+    tblock->name);
+
+/* If a fixed uid field is set, then a gid field must also be set. */
+
+if (tblock->uid_set && !tblock->gid_set && tblock->expand_gid == NULL)
+  log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
+    "user set without group for the %s transport", tblock->name);
+
+/* Set up the bitwise options for transport_write_message from the various
+driver options. Only one of body_only and headers_only can be set. */
+
+ob->options |=
+  (tblock->body_only? topt_no_headers : 0) |
+  (tblock->headers_only? topt_no_body : 0) |
+  (tblock->return_path_add? topt_add_return_path : 0) |
+  (tblock->delivery_date_add? topt_add_delivery_date : 0) |
+  (tblock->envelope_to_add? topt_add_envelope_to : 0) |
+  topt_use_crlf | topt_end_dot;
+}
+
+
+/*************************************************
+*          Check an LMTP response                *
+*************************************************/
+
+/* This function is given an errno code and the LMTP response buffer to
+analyse. It sets an appropriate message and puts the first digit of the
+response code into the yield variable. If no response was actually read, a
+suitable digit is chosen.
+
+Arguments:
+  errno_value  pointer to the errno value
+  more_errno   from the top address for use with ERRNO_FILTER_FAIL
+  buffer       the LMTP response buffer
+  yield        where to put a one-digit LMTP response code
+  message      where to put an error message
+
+Returns:       TRUE if a "QUIT" command should be sent, else FALSE
+*/
+
+static BOOL
+check_response(int *errno_value, int more_errno, uschar *buffer,
+  int *yield, uschar **message)
+{
+*yield = '4';    /* Default setting is to give a temporary error */
+
+/* Handle response timeout */
+
+if (*errno_value == ETIMEDOUT)
+  {
+  *message = string_sprintf("LMTP timeout after %s", big_buffer);
+  if (transport_count > 0)
+    *message = string_sprintf("%s (%d bytes written)", *message,
+      transport_count);
+  *errno_value = 0;
+  return FALSE;
+  }
+
+/* Handle malformed LMTP response */
+
+if (*errno_value == ERRNO_SMTPFORMAT)
+  {
+  *message = string_sprintf("Malformed LMTP response after %s: %s",
+    big_buffer, string_printing(buffer));
+  return FALSE;
+  }
+
+/* Handle a failed filter process error; can't send QUIT as we mustn't
+end the DATA. */
+
+if (*errno_value == ERRNO_FILTER_FAIL)
+  {
+  *message = string_sprintf("transport filter process failed (%d)%s",
+    more_errno,
+    (more_errno == EX_EXECFAILED)? ": unable to execute command" : "");
+  return FALSE;
+  }
+
+/* Handle a failed add_headers expansion; can't send QUIT as we mustn't
+end the DATA. */
+
+if (*errno_value == ERRNO_CHHEADER_FAIL)
+  {
+  *message =
+    string_sprintf("failed to expand headers_add or headers_remove: %s",
+      expand_string_message);
+  return FALSE;
+  }
+
+/* Handle failure to write a complete data block */
+
+if (*errno_value == ERRNO_WRITEINCOMPLETE)
+  {
+  *message = US"failed to write a data block";
+  return FALSE;
+  }
+
+/* Handle error responses from the remote process. */
+
+if (buffer[0] != 0)
+  {
+  const uschar *s = string_printing(buffer);
+  *message = string_sprintf("LMTP error after %s: %s", big_buffer, s);
+  *yield = buffer[0];
+  return TRUE;
+  }
+
+/* No data was read. If there is no errno, this must be the EOF (i.e.
+connection closed) case, which causes deferral. Otherwise, leave the errno
+value to be interpreted. In all cases, we have to assume the connection is now
+dead. */
+
+if (*errno_value == 0)
+  {
+  *errno_value = ERRNO_SMTPCLOSED;
+  *message = string_sprintf("LMTP connection closed after %s", big_buffer);
+  }
+
+return FALSE;
+}
+
+
+
+/*************************************************
+*             Write LMTP command                 *
+*************************************************/
+
+/* The formatted command is left in big_buffer so that it can be reflected in
+any error message.
+
+Arguments:
+  fd         the fd to write to
+  format     a format, starting with one of
+             of HELO, MAIL FROM, RCPT TO, DATA, ".", or QUIT.
+  ...        data for the format
+
+Returns:     TRUE if successful, FALSE if not, with errno set
+*/
+
+static BOOL
+lmtp_write_command(int fd, const char *format, ...)
+{
+gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer };
+int rc;
+va_list ap;
+
+/*XXX see comment in smtp_write_command() regarding leaving stuff in
+big_buffer */
+
+va_start(ap, format);
+if (!string_vformat(&gs, SVFMT_TAINT_NOCHK, CS format, ap))
+  {
+  va_end(ap);
+  errno = ERRNO_SMTPFORMAT;
+  return FALSE;
+  }
+va_end(ap);
+DEBUG(D_transport|D_v) debug_printf("  LMTP>> %s", string_from_gstring(&gs));
+rc = write(fd, gs.s, gs.ptr);
+gs.ptr -= 2; string_from_gstring(&gs); /* remove \r\n for debug and error message */
+if (rc > 0) return TRUE;
+DEBUG(D_transport) debug_printf("write failed: %s\n", strerror(errno));
+return FALSE;
+}
+
+
+
+
+/*************************************************
+*              Read LMTP response                *
+*************************************************/
+
+/* This function reads an LMTP response with a timeout, and returns the
+response in the given buffer. It also analyzes the first digit of the reply
+code and returns FALSE if it is not acceptable.
+
+FALSE is also returned after a reading error. In this case buffer[0] will be
+zero, and the error code will be in errno.
+
+Arguments:
+  f         a file to read from
+  buffer    where to put the response
+  size      the size of the buffer
+  okdigit   the expected first digit of the response
+  timeout   the timeout to use
+
+Returns:    TRUE if a valid, non-error response was received; else FALSE
+*/
+
+static BOOL
+lmtp_read_response(FILE *f, uschar *buffer, int size, int okdigit, int timeout)
+{
+int count;
+uschar *ptr = buffer;
+uschar *readptr = buffer;
+
+/* Ensure errno starts out zero */
+
+errno = 0;
+
+/* Loop for handling LMTP responses that do not all come in one line. */
+
+for (;;)
+  {
+  /* If buffer is too full, something has gone wrong. */
+
+  if (size < 10)
+    {
+    *readptr = 0;
+    errno = ERRNO_SMTPFORMAT;
+    return FALSE;
+    }
+
+  /* Loop to cover the read getting interrupted. */
+
+  for (;;)
+    {
+    char *rc;
+    int save_errno;
+
+    *readptr = 0;           /* In case nothing gets read */
+    sigalrm_seen = FALSE;
+    ALARM(timeout);
+    rc = Ufgets(readptr, size-1, f);
+    save_errno = errno;
+    ALARM_CLR(0);
+    errno = save_errno;
+
+    if (rc != NULL) break;  /* A line has been read */
+
+    /* Handle timeout; must do this first because it uses EINTR */
+
+    if (sigalrm_seen) errno = ETIMEDOUT;
+
+    /* If some other interrupt arrived, just retry. We presume this to be rare,
+    but it can happen (e.g. the SIGUSR1 signal sent by exiwhat causes
+    read() to exit). */
+
+    else if (errno == EINTR)
+      {
+      DEBUG(D_transport) debug_printf("EINTR while reading LMTP response\n");
+      continue;
+      }
+
+    /* Handle other errors, including EOF; ensure buffer is completely empty. */
+
+    buffer[0] = 0;
+    return FALSE;
+    }
+
+  /* Adjust size in case we have to read another line, and adjust the
+  count to be the length of the line we are about to inspect. */
+
+  count = Ustrlen(readptr);
+  size -= count;
+  count += readptr - ptr;
+
+  /* See if the final two characters in the buffer are \r\n. If not, we
+  have to read some more. At least, that is what we should do on a strict
+  interpretation of the RFC. But accept LF as well, as we do for SMTP. */
+
+  if (ptr[count-1] != '\n')
+    {
+    DEBUG(D_transport)
+      {
+      debug_printf("LMTP input line incomplete in one buffer:\n  ");
+      for (int i = 0; i < count; i++)
+        {
+        int c = (ptr[i]);
+        if (mac_isprint(c)) debug_printf("%c", c); else debug_printf("<%d>", c);
+        }
+      debug_printf("\n");
+      }
+    readptr = ptr + count;
+    continue;
+    }
+
+  /* Remove any whitespace at the end of the buffer. This gets rid of CR, LF
+  etc. at the end. Show it, if debugging, formatting multi-line responses. */
+
+  while (count > 0 && isspace(ptr[count-1])) count--;
+  ptr[count] = 0;
+
+  DEBUG(D_transport|D_v)
+    {
+    uschar *s = ptr;
+    uschar *t = ptr;
+    while (*t != 0)
+      {
+      while (*t != 0 && *t != '\n') t++;
+      debug_printf("  %s %*s\n", (s == ptr)? "LMTP<<" : "      ",
+        (int)(t-s), s);
+      if (*t == 0) break;
+      s = t = t + 1;
+      }
+    }
+
+  /* Check the format of the response: it must start with three digits; if
+  these are followed by a space or end of line, the response is complete. If
+  they are followed by '-' this is a multi-line response and we must look for
+  another line until the final line is reached. The only use made of multi-line
+  responses is to pass them back as error messages. We therefore just
+  concatenate them all within the buffer, which should be large enough to
+  accept any reasonable number of lines. A multiline response may already
+  have been read in one go - hence the loop here. */
+
+  for(;;)
+    {
+    uschar *p;
+    if (count < 3 ||
+       !isdigit(ptr[0]) ||
+       !isdigit(ptr[1]) ||
+       !isdigit(ptr[2]) ||
+       (ptr[3] != '-' && ptr[3] != ' ' && ptr[3] != 0))
+      {
+      errno = ERRNO_SMTPFORMAT;    /* format error */
+      return FALSE;
+      }
+
+    /* If a single-line response, exit the loop */
+
+    if (ptr[3] != '-') break;
+
+    /* For a multi-line response see if the next line is already read, and if
+    so, stay in this loop to check it. */
+
+    p = ptr + 3;
+    while (*(++p) != 0)
+      {
+      if (*p == '\n')
+        {
+        ptr = ++p;
+        break;
+        }
+      }
+    if (*p == 0) break;   /* No more lines to check */
+    }
+
+  /* End of response. If the last of the lines we are looking at is the final
+  line, we are done. Otherwise more data has to be read. */
+
+  if (ptr[3] != '-') break;
+
+  /* Move the reading pointer upwards in the buffer and insert \n in case this
+  is an error message that subsequently gets printed. Set the scanning pointer
+  to the reading pointer position. */
+
+  ptr += count;
+  *ptr++ = '\n';
+  size--;
+  readptr = ptr;
+  }
+
+/* Return a value that depends on the LMTP return code. Ensure that errno is
+zero, because the caller of this function looks at errno when FALSE is
+returned, to distinguish between an unexpected return code and other errors
+such as timeouts, lost connections, etc. */
+
+errno = 0;
+return buffer[0] == okdigit;
+}
+
+
+
+
+
+
+/*************************************************
+*              Main entry point                  *
+*************************************************/
+
+/* See local README for interface details. For setup-errors, this transport
+returns FALSE, indicating that the first address has the status for all; in
+normal cases it returns TRUE, indicating that each address has its own status
+set. */
+
+BOOL
+lmtp_transport_entry(
+  transport_instance *tblock,      /* data for this instantiation */
+  address_item *addrlist)          /* address(es) we are working on */
+{
+pid_t pid = 0;
+FILE *out;
+lmtp_transport_options_block *ob =
+  (lmtp_transport_options_block *)(tblock->options_block);
+struct sockaddr_un sockun;         /* don't call this "sun" ! */
+int timeout = ob->timeout;
+int fd_in = -1, fd_out = -1;
+int code, save_errno;
+BOOL send_data;
+BOOL yield = FALSE;
+uschar *igquotstr = US"";
+uschar *sockname = NULL;
+const uschar **argv;
+uschar buffer[256];
+
+DEBUG(D_transport) debug_printf("%s transport entered\n", tblock->name);
+
+/* Initialization ensures that either a command or a socket is specified, but
+not both. When a command is specified, call the common function for creating an
+argument list and expanding the items. */
+
+if (ob->cmd)
+  {
+  DEBUG(D_transport) debug_printf("using command %s\n", ob->cmd);
+  sprintf(CS buffer, "%.50s transport", tblock->name);
+  if (!transport_set_up_command(&argv, ob->cmd, TRUE, PANIC, addrlist, buffer,
+       NULL))
+    return FALSE;
+
+  /* If the -N option is set, can't do any more. Presume all has gone well. */
+  if (f.dont_deliver)
+    goto MINUS_N;
+
+/* As this is a local transport, we are already running with the required
+uid/gid and current directory. Request that the new process be a process group
+leader, so we can kill it and all its children on an error. */
+
+  if ((pid = child_open(USS argv, NULL, 0, &fd_in, &fd_out, TRUE,
+			US"lmtp-tpt-cmd")) < 0)
+    {
+    addrlist->message = string_sprintf(
+      "Failed to create child process for %s transport: %s", tblock->name,
+        strerror(errno));
+    return FALSE;
+    }
+  }
+
+/* When a socket is specified, expand the string and create a socket. */
+
+else
+  {
+  DEBUG(D_transport) debug_printf("using socket %s\n", ob->skt);
+  if (!(sockname = expand_string(ob->skt)))
+    {
+    addrlist->message = string_sprintf("Expansion of \"%s\" (socket setting "
+      "for %s transport) failed: %s", ob->skt, tblock->name,
+      expand_string_message);
+    return FALSE;
+    }
+  if ((fd_in = fd_out = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
+    {
+    addrlist->message = string_sprintf(
+      "Failed to create socket %s for %s transport: %s",
+        ob->skt, tblock->name, strerror(errno));
+    return FALSE;
+    }
+
+  /* If the -N option is set, can't do any more. Presume all has gone well. */
+  if (f.dont_deliver)
+    goto MINUS_N;
+
+  sockun.sun_family = AF_UNIX;
+  sprintf(sockun.sun_path, "%.*s", (int)(sizeof(sockun.sun_path)-1), sockname);
+  if(connect(fd_out, (struct sockaddr *)(&sockun), sizeof(sockun)) == -1)
+    {
+    addrlist->message = string_sprintf(
+      "Failed to connect to socket %s for %s transport: %s",
+        sockun.sun_path, tblock->name, strerror(errno));
+    return FALSE;
+    }
+  }
+
+
+/* Make the output we are going to read into a file. */
+
+out = fdopen(fd_out, "rb");
+
+/* Now we must implement the LMTP protocol. It is like SMTP, except that after
+the end of the message, a return code for every accepted RCPT TO is sent. This
+allows for message+recipient checks after the message has been received. */
+
+/* First thing is to wait for an initial greeting. */
+
+Ustrcpy(big_buffer, US"initial connection");
+if (!lmtp_read_response(out, buffer, sizeof(buffer), '2',
+  timeout)) goto RESPONSE_FAILED;
+
+/* Next, we send a LHLO command, and expect a positive response */
+
+if (!lmtp_write_command(fd_in, "%s %s\r\n", "LHLO",
+  primary_hostname)) goto WRITE_FAILED;
+
+if (!lmtp_read_response(out, buffer, sizeof(buffer), '2',
+     timeout)) goto RESPONSE_FAILED;
+
+/* If the ignore_quota option is set, note whether the server supports the
+IGNOREQUOTA option, and if so, set an appropriate addition for RCPT. */
+
+if (ob->ignore_quota)
+  igquotstr = (pcre_exec(regex_IGNOREQUOTA, NULL, CS buffer,
+    Ustrlen(CS buffer), 0, PCRE_EOPT, NULL, 0) >= 0)? US" IGNOREQUOTA" : US"";
+
+/* Now the envelope sender */
+
+if (!lmtp_write_command(fd_in, "MAIL FROM:<%s>\r\n", return_path))
+  goto WRITE_FAILED;
+
+if (!lmtp_read_response(out, buffer, sizeof(buffer), '2', timeout))
+  {
+  if (errno == 0 && buffer[0] == '4')
+    {
+    errno = ERRNO_MAIL4XX;
+    addrlist->more_errno |= ((buffer[1] - '0')*10 + buffer[2] - '0') << 8;
+    }
+  goto RESPONSE_FAILED;
+  }
+
+/* Next, we hand over all the recipients. Some may be permanently or
+temporarily rejected; others may be accepted, for now. */
+
+send_data = FALSE;
+for (address_item * addr = addrlist; addr; addr = addr->next)
+  {
+  if (!lmtp_write_command(fd_in, "RCPT TO:<%s>%s\r\n",
+       transport_rcpt_address(addr, tblock->rcpt_include_affixes), igquotstr))
+    goto WRITE_FAILED;
+  if (lmtp_read_response(out, buffer, sizeof(buffer), '2', timeout))
+    {
+    send_data = TRUE;
+    addr->transport_return = PENDING_OK;
+    }
+  else
+    {
+    if (errno != 0 || buffer[0] == 0) goto RESPONSE_FAILED;
+    addr->message = string_sprintf("LMTP error after %s: %s", big_buffer,
+      string_printing(buffer));
+    setflag(addr, af_pass_message);   /* Allow message to go to user */
+    if (buffer[0] == '5') addr->transport_return = FAIL; else
+      {
+      addr->basic_errno = ERRNO_RCPT4XX;
+      addr->more_errno |= ((buffer[1] - '0')*10 + buffer[2] - '0') << 8;
+      }
+    }
+  }
+
+/* Now send the text of the message if there were any good recipients. */
+
+if (send_data)
+  {
+  BOOL ok;
+  transport_ctx tctx = {
+    {fd_in},
+    tblock,
+    addrlist,
+    US".", US"..",
+    ob->options
+  };
+
+  if (!lmtp_write_command(fd_in, "DATA\r\n")) goto WRITE_FAILED;
+  if (!lmtp_read_response(out, buffer, sizeof(buffer), '3', timeout))
+    {
+    if (errno == 0 && buffer[0] == '4')
+      {
+      errno = ERRNO_DATA4XX;
+      addrlist->more_errno |= ((buffer[1] - '0')*10 + buffer[2] - '0') << 8;
+      }
+    goto RESPONSE_FAILED;
+    }
+
+  sigalrm_seen = FALSE;
+  transport_write_timeout = timeout;
+  Ustrcpy(big_buffer, US"sending data block");   /* For error messages */
+  DEBUG(D_transport|D_v)
+    debug_printf("  LMTP>> writing message and terminating \".\"\n");
+
+  transport_count = 0;
+  ok = transport_write_message(&tctx, 0);
+
+  /* Failure can either be some kind of I/O disaster (including timeout),
+  or the failure of a transport filter or the expansion of added headers. */
+
+  if (!ok)
+    {
+    buffer[0] = 0;              /* There hasn't been a response */
+    goto RESPONSE_FAILED;
+    }
+
+  Ustrcpy(big_buffer, US"end of data");   /* For error messages */
+
+  /* We now expect a response for every address that was accepted above,
+  in the same order. For those that get a response, their status is fixed;
+  any that are accepted have been handed over, even if later responses crash -
+  at least, that's how I read RFC 2033. */
+
+  for (address_item * addr = addrlist; addr; addr = addr->next)
+    {
+    if (addr->transport_return != PENDING_OK) continue;
+
+    if (lmtp_read_response(out, buffer, sizeof(buffer), '2', timeout))
+      {
+      addr->transport_return = OK;
+      if (LOGGING(smtp_confirmation))
+        {
+        const uschar *s = string_printing(buffer);
+	/* de-const safe here as string_printing known to have alloc'n'copied */
+        addr->message = (s == buffer)? US string_copy(s) : US s;
+        }
+      }
+    /* If the response has failed badly, use it for all the remaining pending
+    addresses and give up. */
+
+    else if (errno != 0 || buffer[0] == 0)
+      {
+      save_errno = errno;
+      check_response(&save_errno, addr->more_errno, buffer, &code,
+        &(addr->message));
+      addr->transport_return = (code == '5')? FAIL : DEFER;
+      for (address_item * a = addr->next; a; a = a->next)
+        {
+        if (a->transport_return != PENDING_OK) continue;
+        a->basic_errno = addr->basic_errno;
+        a->message = addr->message;
+        a->transport_return = addr->transport_return;
+        }
+      break;
+      }
+
+    /* Otherwise, it's an LMTP error code return for one address */
+
+    else
+      {
+      if (buffer[0] == '4')
+        {
+        addr->basic_errno = ERRNO_DATA4XX;
+        addr->more_errno |= ((buffer[1] - '0')*10 + buffer[2] - '0') << 8;
+        }
+      addr->message = string_sprintf("LMTP error after %s: %s", big_buffer,
+        string_printing(buffer));
+      addr->transport_return = (buffer[0] == '5')? FAIL : DEFER;
+      setflag(addr, af_pass_message);   /* Allow message to go to user */
+      }
+    }
+  }
+
+/* The message transaction has completed successfully - this doesn't mean that
+all the addresses have necessarily been transferred, but each has its status
+set, so we change the yield to TRUE. */
+
+yield = TRUE;
+(void) lmtp_write_command(fd_in, "QUIT\r\n");
+(void) lmtp_read_response(out, buffer, sizeof(buffer), '2', 1);
+
+goto RETURN;
+
+
+/* Come here if any call to read_response, other than a response after the data
+phase, failed. Put the error in the top address - this will be replicated
+because the yield is still FALSE. (But omit ETIMEDOUT, as there will already be
+a suitable message.) Analyse the error, and if if isn't too bad, send a QUIT
+command. Wait for the response with a short timeout, so we don't wind up this
+process before the far end has had time to read the QUIT. */
+
+RESPONSE_FAILED:
+
+save_errno = errno;
+if (errno != ETIMEDOUT && errno != 0) addrlist->basic_errno = errno;
+addrlist->message = NULL;
+
+if (check_response(&save_errno, addrlist->more_errno,
+    buffer, &code, &(addrlist->message)))
+  {
+  (void) lmtp_write_command(fd_in, "QUIT\r\n");
+  (void) lmtp_read_response(out, buffer, sizeof(buffer), '2', 1);
+  }
+
+addrlist->transport_return = (code == '5')? FAIL : DEFER;
+if (code == '4' && save_errno > 0)
+  addrlist->message = string_sprintf("%s: %s", addrlist->message,
+    strerror(save_errno));
+goto KILL_AND_RETURN;
+
+/* Come here if there are errors during writing of a command or the message
+itself. This error will be applied to all the addresses. */
+
+WRITE_FAILED:
+
+addrlist->transport_return = PANIC;
+addrlist->basic_errno = errno;
+if (errno == ERRNO_CHHEADER_FAIL)
+  addrlist->message =
+    string_sprintf("Failed to expand headers_add or headers_remove: %s",
+      expand_string_message);
+else if (errno == ERRNO_FILTER_FAIL)
+  addrlist->message = US"Filter process failure";
+else if (errno == ERRNO_WRITEINCOMPLETE)
+  addrlist->message = US"Failed repeatedly to write data";
+else if (errno == ERRNO_SMTPFORMAT)
+  addrlist->message = US"overlong LMTP command generated";
+else
+  addrlist->message = string_sprintf("Error %d", errno);
+
+/* Come here after errors. Kill off the process. */
+
+KILL_AND_RETURN:
+
+if (pid > 0) killpg(pid, SIGKILL);
+
+/* Come here from all paths after the subprocess is created. Wait for the
+process, but with a timeout. */
+
+RETURN:
+
+(void)child_close(pid, timeout);
+
+if (fd_in >= 0) (void)close(fd_in);
+if (fd_out >= 0) (void)fclose(out);
+
+DEBUG(D_transport)
+  debug_printf("%s transport yields %d\n", tblock->name, yield);
+
+return yield;
+
+
+MINUS_N:
+  DEBUG(D_transport)
+    debug_printf("*** delivery by %s transport bypassed by -N option",
+      tblock->name);
+  addrlist->transport_return = OK;
+  return FALSE;
+}
+
+#endif	/*!MACRO_PREDEF*/
+/* End of transport/lmtp.c */
diff --git a/src/transports/lmtp.h b/src/transports/lmtp.h
new file mode 100644
index 0000000..93f0f89
--- /dev/null
+++ b/src/transports/lmtp.h
@@ -0,0 +1,32 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+/* Copyright (c) University of Cambridge 1995 - 2009 */
+/* See the file NOTICE for conditions of use and distribution. */
+
+/* Private structure for the private options. */
+
+typedef struct {
+  uschar *cmd;
+  uschar *skt;
+  int   timeout;
+  int   options;
+  BOOL  ignore_quota;
+} lmtp_transport_options_block;
+
+/* Data for reading the private options. */
+
+extern optionlist lmtp_transport_options[];
+extern int lmtp_transport_options_count;
+
+/* Block containing default values. */
+
+extern lmtp_transport_options_block lmtp_transport_option_defaults;
+
+/* The main and init entry points for the transport */
+
+extern BOOL lmtp_transport_entry(transport_instance *, address_item *);
+extern void lmtp_transport_init(transport_instance *);
+
+/* End of transports/lmtp.h */
diff --git a/src/transports/pipe.c b/src/transports/pipe.c
new file mode 100644
index 0000000..27422bd
--- /dev/null
+++ b/src/transports/pipe.c
@@ -0,0 +1,1145 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+/* Copyright (c) University of Cambridge 1995 - 2018 */
+/* Copyright (c) The Exim maintainers 2020 */
+/* See the file NOTICE for conditions of use and distribution. */
+
+
+#include "../exim.h"
+#include "pipe.h"
+
+#ifdef HAVE_SETCLASSRESOURCES
+#include <login_cap.h>
+#endif
+
+
+
+/* Options specific to the pipe transport. They must be in alphabetic
+order (note that "_" comes before the lower case letters). Those starting
+with "*" are not settable by the user but are used by the option-reading
+software for alternative value types. Some options are stored in the transport
+instance block so as to be publicly visible; these are flagged with opt_public.
+*/
+#define LOFF(field) OPT_OFF(pipe_transport_options_block, field)
+
+optionlist pipe_transport_options[] = {
+  { "allow_commands",    opt_stringptr,	LOFF(allow_commands) },
+  { "batch_id",          opt_stringptr | opt_public,
+      OPT_OFF(transport_instance, batch_id) },
+  { "batch_max",         opt_int | opt_public,
+      OPT_OFF(transport_instance, batch_max) },
+  { "check_string",      opt_stringptr,	LOFF(check_string) },
+  { "command",           opt_stringptr,	LOFF(cmd) },
+  { "environment",       opt_stringptr,	LOFF(environment) },
+  { "escape_string",     opt_stringptr,	LOFF(escape_string) },
+  { "force_command",         opt_bool,	LOFF(force_command) },
+  { "freeze_exec_fail",  opt_bool,	LOFF(freeze_exec_fail) },
+  { "freeze_signal",     opt_bool,	LOFF(freeze_signal) },
+  { "ignore_status",     opt_bool,	LOFF(ignore_status) },
+  { "log_defer_output",  opt_bool | opt_public,
+      OPT_OFF(transport_instance, log_defer_output) },
+  { "log_fail_output",   opt_bool | opt_public,
+      OPT_OFF(transport_instance, log_fail_output) },
+  { "log_output",        opt_bool | opt_public,
+      OPT_OFF(transport_instance, log_output) },
+  { "max_output",        opt_mkint,	LOFF(max_output) },
+  { "message_prefix",    opt_stringptr,	LOFF(message_prefix) },
+  { "message_suffix",    opt_stringptr,	LOFF(message_suffix) },
+  { "path",              opt_stringptr,	LOFF(path) },
+  { "permit_coredump",   opt_bool,	LOFF(permit_coredump) },
+  { "pipe_as_creator",   opt_bool | opt_public,
+      OPT_OFF(transport_instance, deliver_as_creator) },
+  { "restrict_to_path",  opt_bool,	LOFF(restrict_to_path) },
+  { "return_fail_output",opt_bool | opt_public,
+      OPT_OFF(transport_instance, return_fail_output) },
+  { "return_output",     opt_bool | opt_public,
+      OPT_OFF(transport_instance, return_output) },
+  { "temp_errors",       opt_stringptr,	LOFF(temp_errors) },
+  { "timeout",           opt_time,	LOFF(timeout) },
+  { "timeout_defer",     opt_bool,	LOFF(timeout_defer) },
+  { "umask",             opt_octint,	LOFF(umask) },
+  { "use_bsmtp",         opt_bool,	LOFF(use_bsmtp) },
+  #ifdef HAVE_SETCLASSRESOURCES
+  { "use_classresources", opt_bool,	LOFF(use_classresources) },
+  #endif
+  { "use_crlf",          opt_bool,	LOFF(use_crlf) },
+  { "use_shell",         opt_bool,	LOFF(use_shell) },
+};
+
+/* Size of the options list. An extern variable has to be used so that its
+address can appear in the tables drtables.c. */
+
+int pipe_transport_options_count =
+  sizeof(pipe_transport_options)/sizeof(optionlist);
+
+
+#ifdef MACRO_PREDEF
+
+/* Dummy values */
+pipe_transport_options_block pipe_transport_option_defaults = {0};
+void pipe_transport_init(transport_instance *tblock) {}
+BOOL pipe_transport_entry(transport_instance *tblock, address_item *addr) {return FALSE;}
+
+#else   /*!MACRO_PREDEF*/
+
+
+/* Default private options block for the pipe transport. */
+
+pipe_transport_options_block pipe_transport_option_defaults = {
+  NULL,           /* cmd */
+  NULL,           /* allow_commands */
+  NULL,           /* environment */
+  US"/bin:/usr/bin",  /* path */
+  NULL,           /* message_prefix (reset in init if not bsmtp) */
+  NULL,           /* message_suffix (ditto) */
+  US mac_expanded_string(EX_TEMPFAIL) ":"    /* temp_errors */
+     mac_expanded_string(EX_CANTCREAT),
+  NULL,           /* check_string */
+  NULL,           /* escape_string */
+  022,            /* umask */
+  20480,          /* max_output */
+  60*60,          /* timeout */
+  0,              /* options */
+  FALSE,          /* force_command */
+  FALSE,          /* freeze_exec_fail */
+  FALSE,          /* freeze_signal */
+  FALSE,          /* ignore_status */
+  FALSE,          /* permit_coredump */
+  FALSE,          /* restrict_to_path */
+  FALSE,          /* timeout_defer */
+  FALSE,          /* use_shell */
+  FALSE,          /* use_bsmtp */
+  FALSE,          /* use_classresources */
+  FALSE           /* use_crlf */
+};
+
+
+
+/*************************************************
+*              Setup entry point                 *
+*************************************************/
+
+/* Called for each delivery in the privileged state, just before the uid/gid
+are changed and the main entry point is called. In a system that supports the
+login_cap facilities, this function is used to set the class resource limits
+for the user.  It may also re-enable coredumps.
+
+Arguments:
+  tblock     points to the transport instance
+  addrlist   addresses about to be delivered (not used)
+  dummy      not used (doesn't pass back data)
+  uid        the uid that will be set (not used)
+  gid        the gid that will be set (not used)
+  errmsg     where to put an error message
+
+Returns:     OK, FAIL, or DEFER
+*/
+
+static int
+pipe_transport_setup(transport_instance *tblock, address_item *addrlist,
+  transport_feedback *dummy, uid_t uid, gid_t gid, uschar **errmsg)
+{
+pipe_transport_options_block *ob =
+  (pipe_transport_options_block *)(tblock->options_block);
+
+addrlist = addrlist;  /* Keep compiler happy */
+dummy = dummy;
+uid = uid;
+gid = gid;
+errmsg = errmsg;
+ob = ob;
+
+#ifdef HAVE_SETCLASSRESOURCES
+if (ob->use_classresources)
+  {
+  struct passwd *pw = getpwuid(uid);
+  if (pw != NULL)
+    {
+    login_cap_t *lc = login_getpwclass(pw);
+    if (lc != NULL)
+      {
+      setclassresources(lc);
+      login_close(lc);
+      }
+    }
+  }
+#endif
+
+#ifdef RLIMIT_CORE
+if (ob->permit_coredump)
+  {
+  struct rlimit rl;
+  rl.rlim_cur = RLIM_INFINITY;
+  rl.rlim_max = RLIM_INFINITY;
+  if (setrlimit(RLIMIT_CORE, &rl) < 0)
+    {
+#ifdef SETRLIMIT_NOT_SUPPORTED
+    if (errno != ENOSYS && errno != ENOTSUP)
+#endif
+      log_write(0, LOG_MAIN,
+          "delivery setrlimit(RLIMIT_CORE, RLIM_INFINITY) failed: %s",
+          strerror(errno));
+    }
+  }
+#endif
+
+return OK;
+}
+
+
+
+/*************************************************
+*          Initialization entry point            *
+*************************************************/
+
+/* Called for each instance, after its options have been read, to
+enable consistency checks to be done, or anything else that needs
+to be set up. */
+
+void
+pipe_transport_init(transport_instance *tblock)
+{
+pipe_transport_options_block *ob =
+  (pipe_transport_options_block *)(tblock->options_block);
+
+/* Set up the setup entry point, to be called in the privileged state */
+
+tblock->setup = pipe_transport_setup;
+
+/* If pipe_as_creator is set, then uid/gid should not be set. */
+
+if (tblock->deliver_as_creator && (tblock->uid_set || tblock->gid_set ||
+  tblock->expand_uid != NULL || tblock->expand_gid != NULL))
+    log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
+      "both pipe_as_creator and an explicit uid/gid are set for the %s "
+        "transport", tblock->name);
+
+/* If a fixed uid field is set, then a gid field must also be set. */
+
+if (tblock->uid_set && !tblock->gid_set && tblock->expand_gid == NULL)
+  log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
+    "user set without group for the %s transport", tblock->name);
+
+/* Temp_errors must consist only of digits and colons, but there can be
+spaces round the colons, so allow them too. */
+
+if (ob->temp_errors != NULL && Ustrcmp(ob->temp_errors, "*") != 0)
+  {
+  size_t p = Ustrspn(ob->temp_errors, "0123456789: ");
+  if (ob->temp_errors[p] != 0)
+    log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
+      "temp_errors must be a list of numbers or an asterisk for the %s "
+      "transport", tblock->name);
+  }
+
+/* Only one of return_output/return_fail_output or log_output/log_fail_output
+should be set. */
+
+if (tblock->return_output && tblock->return_fail_output)
+  log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
+    "both return_output and return_fail_output set for %s transport",
+    tblock->name);
+
+if (tblock->log_output && tblock->log_fail_output)
+  log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
+    "both log_output and log_fail_output set for the %s transport",
+    tblock->name);
+
+/* If batch SMTP is set, force the check and escape strings, and arrange that
+headers are also escaped. */
+
+if (ob->use_bsmtp)
+  {
+  ob->check_string = US".";
+  ob->escape_string = US"..";
+  ob->options |= topt_escape_headers;
+  }
+
+/* If not batch SMTP, and message_prefix or message_suffix are unset, insert
+default values for them. */
+
+else
+  {
+  if (ob->message_prefix == NULL) ob->message_prefix =
+    US"From ${if def:return_path{$return_path}{MAILER-DAEMON}} ${tod_bsdinbox}\n";
+  if (ob->message_suffix == NULL) ob->message_suffix = US"\n";
+  }
+
+/* The restrict_to_path  and use_shell options are incompatible */
+
+if (ob->restrict_to_path && ob->use_shell)
+  log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
+    "both restrict_to_path and use_shell set for %s transport",
+    tblock->name);
+
+/* The allow_commands and use_shell options are incompatible */
+
+if (ob->allow_commands && ob->use_shell)
+  log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
+    "both allow_commands and use_shell set for %s transport",
+    tblock->name);
+
+/* Set up the bitwise options for transport_write_message from the various
+driver options. Only one of body_only and headers_only can be set. */
+
+ob->options |=
+  (tblock->body_only? topt_no_headers : 0) |
+  (tblock->headers_only? topt_no_body : 0) |
+  (tblock->return_path_add? topt_add_return_path : 0) |
+  (tblock->delivery_date_add? topt_add_delivery_date : 0) |
+  (tblock->envelope_to_add? topt_add_envelope_to : 0) |
+  (ob->use_crlf? topt_use_crlf : 0);
+}
+
+
+
+/*************************************************
+*          Set up direct (non-shell) command     *
+*************************************************/
+
+/* This function is called when a command line is to be parsed by the transport
+and executed directly, without the use of /bin/sh.
+
+Arguments:
+  argvptr            pointer to anchor for argv vector
+  cmd                points to the command string
+  expand_arguments   true if expansion is to occur
+  expand_fail        error if expansion fails
+  addr               chain of addresses
+  tname              the transport name
+  ob                 the transport options block
+
+Returns:             TRUE if all went well; otherwise an error will be
+                     set in the first address and FALSE returned
+*/
+
+static BOOL
+set_up_direct_command(const uschar ***argvptr, uschar *cmd,
+  BOOL expand_arguments, int expand_fail, address_item *addr, uschar *tname,
+  pipe_transport_options_block *ob)
+{
+BOOL permitted = FALSE;
+const uschar **argv;
+
+/* Set up "transport <name>" to be put in any error messages, and then
+call the common function for creating an argument list and expanding
+the items if necessary. If it fails, this function fails (error information
+is in the addresses). */
+
+if (!transport_set_up_command(argvptr, cmd, expand_arguments, expand_fail,
+      addr, string_sprintf("%.50s transport", tname), NULL))
+  return FALSE;
+
+/* Point to the set-up arguments. */
+
+argv = *argvptr;
+
+/* If allow_commands is set, see if the command is in the permitted list. */
+
+if (ob->allow_commands)
+  {
+  int sep = 0;
+  const uschar *s;
+  uschar *p;
+
+  if (!(s = expand_string(ob->allow_commands)))
+    {
+    addr->transport_return = DEFER;
+    addr->message = string_sprintf("failed to expand string \"%s\" "
+      "for %s transport: %s", ob->allow_commands, tname, expand_string_message);
+    return FALSE;
+    }
+
+  while ((p = string_nextinlist(&s, &sep, NULL, 0)))
+    if (Ustrcmp(p, argv[0]) == 0) { permitted = TRUE; break; }
+  }
+
+/* If permitted is TRUE it means the command was found in the allowed list, and
+no further checks are done. If permitted = FALSE, it either means
+allow_commands wasn't set, or that the command didn't match anything in the
+list. In both cases, if restrict_to_path is set, we fail if the command
+contains any slashes, but if restrict_to_path is not set, we must fail the
+command only if allow_commands is set. */
+
+if (!permitted)
+  {
+  if (ob->restrict_to_path)
+    {
+    if (Ustrchr(argv[0], '/') != NULL)
+      {
+      addr->transport_return = FAIL;
+      addr->message = string_sprintf("\"/\" found in \"%s\" (command for %s "
+        "transport) - failed for security reasons", cmd, tname);
+      return FALSE;
+      }
+    }
+
+  else if (ob->allow_commands)
+    {
+    addr->transport_return = FAIL;
+    addr->message = string_sprintf("\"%s\" command not permitted by %s "
+      "transport", argv[0], tname);
+    return FALSE;
+    }
+  }
+
+/* If the command is not an absolute path, search the PATH directories
+for it. */
+
+if (argv[0][0] != '/')
+  {
+  int sep = 0;
+  uschar *p;
+  const uschar *listptr = expand_string(ob->path);
+
+  while ((p = string_nextinlist(&listptr, &sep, NULL, 0)))
+    {
+    struct stat statbuf;
+    sprintf(CS big_buffer, "%.256s/%.256s", p, argv[0]);
+    if (Ustat(big_buffer, &statbuf) == 0)
+      {
+      argv[0] = string_copy(big_buffer);
+      break;
+      }
+    }
+  if (!p)
+    {
+    addr->transport_return = FAIL;
+    addr->message = string_sprintf("\"%s\" command not found for %s transport",
+      argv[0], tname);
+    return FALSE;
+    }
+  }
+
+return TRUE;
+}
+
+
+/*************************************************
+*               Set up shell command             *
+*************************************************/
+
+/* This function is called when a command line is to be passed to /bin/sh
+without parsing inside the transport.
+
+Arguments:
+  argvptr            pointer to anchor for argv vector
+  cmd                points to the command string
+  expand_arguments   true if expansion is to occur
+  expand_fail        error if expansion fails
+  addr               chain of addresses
+  tname              the transport name
+
+Returns:             TRUE if all went well; otherwise an error will be
+                     set in the first address and FALSE returned
+*/
+
+static BOOL
+set_up_shell_command(const uschar ***argvptr, uschar *cmd,
+  BOOL expand_arguments, int expand_fail, address_item *addr, uschar *tname)
+{
+const uschar **argv;
+
+*argvptr = argv = store_get((4)*sizeof(uschar *), FALSE);
+
+argv[0] = US"/bin/sh";
+argv[1] = US"-c";
+
+/* We have to take special action to handle the special "variable" called
+$pipe_addresses, which is not recognized by the normal expansion function. */
+
+if (expand_arguments)
+  {
+  uschar * p = Ustrstr(cmd, "pipe_addresses");
+  gstring * g = NULL;
+
+  DEBUG(D_transport)
+    debug_printf("shell pipe command before expansion:\n  %s\n", cmd);
+
+  /* Allow $recipients in the expansion iff it comes from a system filter */
+
+  f.enable_dollar_recipients = addr && addr->parent &&
+    Ustrcmp(addr->parent->address, "system-filter") == 0;
+
+  if (p != NULL && (
+         (p > cmd && p[-1] == '$') ||
+         (p > cmd + 1 && p[-2] == '$' && p[-1] == '{' && p[14] == '}')))
+    {
+    uschar *q = p + 14;
+
+    if (p[-1] == '{') { q++; p--; }
+
+    g = string_get(Ustrlen(cmd) + 64);
+    g = string_catn(g, cmd, p - cmd - 1);
+
+    for (address_item * ad = addr; ad; ad = ad->next)
+      {
+      /*XXX string_append_listele() ? */
+      if (ad != addr) g = string_catn(g, US" ", 1);
+      g = string_cat(g, ad->address);
+      }
+
+    g = string_cat(g, q);
+    argv[2] = (cmd = string_from_gstring(g)) ? expand_string(cmd) : NULL;
+    }
+  else
+    argv[2] = expand_string(cmd);
+
+  f.enable_dollar_recipients = FALSE;
+
+  if (!argv[2])
+    {
+    addr->transport_return = f.search_find_defer ? DEFER : expand_fail;
+    addr->message = string_sprintf("Expansion of command \"%s\" "
+      "in %s transport failed: %s",
+      cmd, tname, expand_string_message);
+    return FALSE;
+    }
+
+  DEBUG(D_transport)
+    debug_printf("shell pipe command after expansion:\n  %s\n", argv[2]);
+  }
+else
+  {
+  DEBUG(D_transport)
+    debug_printf("shell pipe command (no expansion):\n  %s\n", cmd);
+  argv[2] = cmd;
+  }
+
+argv[3] = US 0;
+return TRUE;
+}
+
+
+
+
+/*************************************************
+*              Main entry point                  *
+*************************************************/
+
+/* See local README for interface details. This transport always returns FALSE,
+indicating that the status in the first address is the status for all addresses
+in a batch. */
+
+BOOL
+pipe_transport_entry(
+  transport_instance *tblock,      /* data for this instantiation */
+  address_item *addr)              /* address(es) we are working on */
+{
+pid_t pid, outpid;
+int fd_in, fd_out, rc;
+int envcount = 0;
+int envsep = 0;
+int expand_fail;
+pipe_transport_options_block *ob =
+  (pipe_transport_options_block *)(tblock->options_block);
+int timeout = ob->timeout;
+BOOL written_ok = FALSE;
+BOOL expand_arguments;
+const uschar **argv;
+uschar *envp[50];
+const uschar *envlist = ob->environment;
+uschar *cmd, *ss;
+uschar *eol = ob->use_crlf ? US"\r\n" : US"\n";
+transport_ctx tctx = {
+  .tblock = tblock,
+  .addr = addr,
+  .check_string = ob->check_string,
+  .escape_string = ob->escape_string,
+  ob->options | topt_not_socket /* set at initialization time */
+};
+
+DEBUG(D_transport) debug_printf("%s transport entered\n", tblock->name);
+
+/* Set up for the good case */
+
+addr->transport_return = OK;
+addr->basic_errno = 0;
+
+/* Pipes are not accepted as general addresses, but they can be generated from
+.forward files or alias files. In those cases, the pfr flag is set, and the
+command to be obeyed is pointed to by addr->local_part; it starts with the pipe
+symbol. In other cases, the command is supplied as one of the pipe transport's
+options. */
+
+if (testflag(addr, af_pfr) && addr->local_part[0] == '|')
+  if (ob->force_command)
+    {
+    /* Enables expansion of $address_pipe into separate arguments */
+    setflag(addr, af_force_command);
+    cmd = ob->cmd;
+    expand_arguments = TRUE;
+    expand_fail = PANIC;
+    }
+  else
+    {
+    cmd = addr->local_part + 1;
+    while (isspace(*cmd)) cmd++;
+    expand_arguments = testflag(addr, af_expand_pipe);
+    expand_fail = FAIL;
+    }
+else
+  {
+  cmd = ob->cmd;
+  expand_arguments = TRUE;
+  expand_fail = PANIC;
+  }
+
+/* If no command has been supplied, we are in trouble.
+ * We also check for an empty string since it may be
+ * coming from addr->local_part[0] == '|'
+ */
+
+if (!cmd || !*cmd)
+  {
+  addr->transport_return = DEFER;
+  addr->message = string_sprintf("no command specified for %s transport",
+    tblock->name);
+  return FALSE;
+  }
+if (is_tainted(cmd))
+  {
+  addr->message = string_sprintf("Tainted '%s' (command "
+    "for %s transport) not permitted", cmd, tblock->name);
+  addr->transport_return = PANIC;
+  return FALSE;
+  }
+
+/* When a pipe is set up by a filter file, there may be values for $thisaddress
+and numerical the variables in existence. These are passed in
+addr->pipe_expandn for use here. */
+
+if (expand_arguments && addr->pipe_expandn)
+  {
+  uschar **ss = addr->pipe_expandn;
+  expand_nmax = -1;
+  if (*ss) filter_thisaddress = *ss++;
+  while (*ss)
+    {
+    expand_nstring[++expand_nmax] = *ss;
+    expand_nlength[expand_nmax] = Ustrlen(*ss++);
+    }
+  }
+
+/* The default way of processing the command is to split it up into arguments
+here, and run it directly. This offers some security advantages. However, there
+are installations that want by default to run commands under /bin/sh always, so
+there is an option to do that. */
+
+if (ob->use_shell)
+  {
+  if (!set_up_shell_command(&argv, cmd, expand_arguments, expand_fail, addr,
+    tblock->name)) return FALSE;
+  }
+else if (!set_up_direct_command(&argv, cmd, expand_arguments, expand_fail, addr,
+  tblock->name, ob)) return FALSE;
+
+expand_nmax = -1;           /* Reset */
+filter_thisaddress = NULL;
+
+/* Set up the environment for the command. */
+
+envp[envcount++] = string_sprintf("LOCAL_PART=%s", deliver_localpart);
+envp[envcount++] = string_sprintf("LOGNAME=%s", deliver_localpart);
+envp[envcount++] = string_sprintf("USER=%s", deliver_localpart);
+envp[envcount++] = string_sprintf("LOCAL_PART_PREFIX=%#s",
+  deliver_localpart_prefix);
+envp[envcount++] = string_sprintf("LOCAL_PART_SUFFIX=%#s",
+  deliver_localpart_suffix);
+envp[envcount++] = string_sprintf("DOMAIN=%s", deliver_domain);
+envp[envcount++] = string_sprintf("HOME=%#s", deliver_home);
+envp[envcount++] = string_sprintf("MESSAGE_ID=%s", message_id);
+envp[envcount++] = string_sprintf("PATH=%s", expand_string(ob->path));
+envp[envcount++] = string_sprintf("RECIPIENT=%#s%#s%#s@%#s",
+  deliver_localpart_prefix, deliver_localpart, deliver_localpart_suffix,
+  deliver_domain);
+envp[envcount++] = string_sprintf("QUALIFY_DOMAIN=%s", qualify_domain_sender);
+envp[envcount++] = string_sprintf("SENDER=%s", sender_address);
+envp[envcount++] = US"SHELL=/bin/sh";
+
+if (addr->host_list != NULL)
+  envp[envcount++] = string_sprintf("HOST=%s", addr->host_list->name);
+
+if (f.timestamps_utc) envp[envcount++] = US"TZ=UTC";
+else if (timezone_string != NULL && timezone_string[0] != 0)
+  envp[envcount++] = string_sprintf("TZ=%s", timezone_string);
+
+/* Add any requested items */
+
+if (envlist)
+  if (!(envlist = expand_cstring(envlist)))
+    {
+    addr->transport_return = DEFER;
+    addr->message = string_sprintf("failed to expand string \"%s\" "
+      "for %s transport: %s", ob->environment, tblock->name,
+      expand_string_message);
+    return FALSE;
+    }
+
+while ((ss = string_nextinlist(&envlist, &envsep, NULL, 0)))
+   {
+   if (envcount > nelem(envp) - 2)
+     {
+     addr->transport_return = DEFER;
+     addr->basic_errno = E2BIG;
+     addr->message = string_sprintf("too many environment settings for "
+       "%s transport", tblock->name);
+     return FALSE;
+     }
+   envp[envcount++] = string_copy(ss);
+   }
+
+envp[envcount] = NULL;
+
+/* If the -N option is set, can't do any more. */
+
+if (f.dont_deliver)
+  {
+  DEBUG(D_transport)
+    debug_printf("*** delivery by %s transport bypassed by -N option",
+      tblock->name);
+  return FALSE;
+  }
+
+
+/* Handling the output from the pipe is tricky. If a file for catching this
+output is provided, we could in theory just hand that fd over to the process,
+but this isn't very safe because it might loop and carry on writing for
+ever (which is exactly what happened in early versions of Exim). Therefore we
+use the standard child_open() function, which creates pipes. We can then read
+our end of the output pipe and count the number of bytes that come through,
+chopping the sub-process if it exceeds some limit.
+
+However, this means we want to run a sub-process with both its input and output
+attached to pipes. We can't handle that easily from a single parent process
+using straightforward code such as the transport_write_message() function
+because the subprocess might not be reading its input because it is trying to
+write to a full output pipe. The complication of redesigning the world to
+handle this is too great - simpler just to run another process to do the
+reading of the output pipe. */
+
+
+/* As this is a local transport, we are already running with the required
+uid/gid and current directory. Request that the new process be a process group
+leader, so we can kill it and all its children on a timeout. */
+
+if ((pid = child_open(USS argv, envp, ob->umask, &fd_in, &fd_out, TRUE,
+			US"pipe-tpt-cmd")) < 0)
+  {
+  addr->transport_return = DEFER;
+  addr->message = string_sprintf(
+    "Failed to create child process for %s transport: %s", tblock->name,
+      strerror(errno));
+  return FALSE;
+  }
+tctx.u.fd = fd_in;
+
+/* Now fork a process to handle the output that comes down the pipe. */
+
+if ((outpid = exim_fork(US"pipe-tpt-output")) < 0)
+  {
+  addr->basic_errno = errno;
+  addr->transport_return = DEFER;
+  addr->message = string_sprintf(
+    "Failed to create process for handling output in %s transport",
+      tblock->name);
+  (void)close(fd_in);
+  (void)close(fd_out);
+  return FALSE;
+  }
+
+/* This is the code for the output-handling subprocess. Read from the pipe
+in chunks, and write to the return file if one is provided. Keep track of
+the number of bytes handled. If the limit is exceeded, try to kill the
+subprocess group, and in any case close the pipe and exit, which should cause
+the subprocess to fail. */
+
+if (outpid == 0)
+  {
+  int count = 0;
+  (void)close(fd_in);
+  set_process_info("reading output from |%s", cmd);
+  while ((rc = read(fd_out, big_buffer, big_buffer_size)) > 0)
+    {
+    if (addr->return_file >= 0)
+      if(write(addr->return_file, big_buffer, rc) != rc)
+        DEBUG(D_transport) debug_printf("Problem writing to return_file\n");
+    count += rc;
+    if (count > ob->max_output)
+      {
+      DEBUG(D_transport) debug_printf("Too much output from pipe - killed\n");
+      if (addr->return_file >= 0)
+	{
+        uschar *message = US"\n\n*** Too much output - remainder discarded ***\n";
+        rc = Ustrlen(message);
+        if(write(addr->return_file, message, rc) != rc)
+          DEBUG(D_transport) debug_printf("Problem writing to return_file\n");
+	}
+      killpg(pid, SIGKILL);
+      break;
+      }
+    }
+  (void)close(fd_out);
+  _exit(0);
+  }
+
+(void)close(fd_out);  /* Not used in this process */
+
+
+/* Carrying on now with the main parent process. Attempt to write the message
+to it down the pipe. It is a fallacy to think that you can detect write errors
+when the sub-process fails to read the pipe. The parent process may complete
+writing and close the pipe before the sub-process completes. We could sleep a
+bit here to let the sub-process get going, but it may still not complete. So we
+ignore all writing errors. (When in the test harness, we do do a short sleep so
+any debugging output is likely to be in the same order.) */
+
+testharness_pause_ms(500);
+
+DEBUG(D_transport) debug_printf("Writing message to pipe\n");
+
+/* Arrange to time out writes if there is a timeout set. */
+
+if (timeout > 0)
+  {
+  sigalrm_seen = FALSE;
+  transport_write_timeout = timeout;
+  }
+
+/* Reset the counter of bytes written */
+
+transport_count = 0;
+
+/* First write any configured prefix information */
+
+if (ob->message_prefix)
+  {
+  uschar *prefix = expand_string(ob->message_prefix);
+  if (!prefix)
+    {
+    addr->transport_return = f.search_find_defer? DEFER : PANIC;
+    addr->message = string_sprintf("Expansion of \"%s\" (prefix for %s "
+      "transport) failed: %s", ob->message_prefix, tblock->name,
+      expand_string_message);
+    return FALSE;
+    }
+  if (!transport_write_block(&tctx, prefix, Ustrlen(prefix), FALSE))
+    goto END_WRITE;
+  }
+
+/* If the use_bsmtp option is set, we need to write SMTP prefix information.
+The various different values for batching are handled outside; if there is more
+than one address available here, all must be included. Force SMTP dot-handling.
+*/
+
+if (ob->use_bsmtp)
+  {
+  if (!transport_write_string(fd_in, "MAIL FROM:<%s>%s", return_path, eol))
+    goto END_WRITE;
+
+  for (address_item * a = addr; a; a = a->next)
+    if (!transport_write_string(fd_in,
+        "RCPT TO:<%s>%s",
+        transport_rcpt_address(a, tblock->rcpt_include_affixes),
+        eol))
+      goto END_WRITE;
+
+  if (!transport_write_string(fd_in, "DATA%s", eol)) goto END_WRITE;
+  }
+
+/* Now the actual message */
+
+if (!transport_write_message(&tctx, 0))
+    goto END_WRITE;
+
+/* Now any configured suffix */
+
+if (ob->message_suffix)
+  {
+  uschar *suffix = expand_string(ob->message_suffix);
+  if (!suffix)
+    {
+    addr->transport_return = f.search_find_defer? DEFER : PANIC;
+    addr->message = string_sprintf("Expansion of \"%s\" (suffix for %s "
+      "transport) failed: %s", ob->message_suffix, tblock->name,
+      expand_string_message);
+    return FALSE;
+    }
+  if (!transport_write_block(&tctx, suffix, Ustrlen(suffix), FALSE))
+    goto END_WRITE;
+  }
+
+/* If local_smtp, write the terminating dot. */
+
+if (ob->use_bsmtp && !transport_write_string(fd_in, ".%s", eol))
+  goto END_WRITE;
+
+/* Flag all writing completed successfully. */
+
+written_ok = TRUE;
+
+/* Come here if there are errors during writing. */
+
+END_WRITE:
+
+/* OK, the writing is now all done. Close the pipe. */
+
+(void) close(fd_in);
+
+/* Handle errors during writing. For timeouts, set the timeout for waiting for
+the child process to 1 second. If the process at the far end of the pipe died
+without reading all of it, we expect an EPIPE error, which should be ignored.
+We used also to ignore WRITEINCOMPLETE but the writing function is now cleverer
+at handling OS where the death of a pipe doesn't give EPIPE immediately. See
+comments therein. */
+
+if (!written_ok)
+  {
+  if (errno == ETIMEDOUT)
+    {
+    addr->message = string_sprintf("%stimeout while writing to pipe",
+      f.transport_filter_timed_out ? "transport filter " : "");
+    addr->transport_return = ob->timeout_defer? DEFER : FAIL;
+    timeout = 1;
+    }
+  else if (errno == EPIPE)
+    {
+    debug_printf("transport error EPIPE ignored\n");
+    }
+  else
+    {
+    addr->transport_return = PANIC;
+    addr->basic_errno = errno;
+    if (errno == ERRNO_CHHEADER_FAIL)
+      addr->message =
+        string_sprintf("Failed to expand headers_add or headers_remove: %s",
+          expand_string_message);
+    else if (errno == ERRNO_FILTER_FAIL)
+      addr->message = string_sprintf("Transport filter process failed (%d)%s",
+      addr->more_errno,
+      (addr->more_errno == EX_EXECFAILED)? ": unable to execute command" : "");
+    else if (errno == ERRNO_WRITEINCOMPLETE)
+      addr->message = US"Failed repeatedly to write data";
+    else
+      addr->message = string_sprintf("Error %d", errno);
+    return FALSE;
+    }
+  }
+
+/* Wait for the child process to complete and take action if the returned
+status is nonzero. The timeout will be just 1 second if any of the writes
+above timed out. */
+
+if ((rc = child_close(pid, timeout)) != 0)
+  {
+  uschar * tmsg = addr->message
+    ? string_sprintf(" (preceded by %s)", addr->message) : US"";
+
+  /* The process did not complete in time; kill its process group and fail
+  the delivery. It appears to be necessary to kill the output process too, as
+  otherwise it hangs on for some time if the actual pipe process is sleeping.
+  (At least, that's what I observed on Solaris 2.5.1.) Since we are failing
+  the delivery, that shouldn't cause any problem. */
+
+  if (rc == -256)
+    {
+    killpg(pid, SIGKILL);
+    kill(outpid, SIGKILL);
+    addr->transport_return = ob->timeout_defer? DEFER : FAIL;
+    addr->message = string_sprintf("pipe delivery process timed out%s", tmsg);
+    }
+
+  /* Wait() failed. */
+
+  else if (rc == -257)
+    {
+    addr->transport_return = PANIC;
+    addr->message = string_sprintf("Wait() failed for child process of %s "
+      "transport: %s%s", tblock->name, strerror(errno), tmsg);
+    }
+
+  /* Since the transport_filter timed out we assume it has sent the child process
+  a malformed or incomplete data stream.  Kill off the child process
+  and prevent checking its exit status as it will has probably exited in error.
+  This prevents the transport_filter timeout message from getting overwritten
+  by the exit error which is not the cause of the problem. */
+
+  else if (f.transport_filter_timed_out)
+    {
+    killpg(pid, SIGKILL);
+    kill(outpid, SIGKILL);
+    }
+
+  /* Either the process completed, but yielded a non-zero (necessarily
+  positive) status, or the process was terminated by a signal (rc will contain
+  the negation of the signal number). Treat killing by signal as failure unless
+  status is being ignored. By default, the message is bounced back, unless
+  freeze_signal is set, in which case it is frozen instead. */
+
+  else if (rc < 0)
+    {
+    if (ob->freeze_signal)
+      {
+      addr->transport_return = DEFER;
+      addr->special_action = SPECIAL_FREEZE;
+      addr->message = string_sprintf("Child process of %s transport (running "
+        "command \"%s\") was terminated by signal %d (%s)%s", tblock->name, cmd,
+        -rc, os_strsignal(-rc), tmsg);
+      }
+    else if (!ob->ignore_status)
+      {
+      addr->transport_return = FAIL;
+      addr->message = string_sprintf("Child process of %s transport (running "
+        "command \"%s\") was terminated by signal %d (%s)%s", tblock->name, cmd,
+        -rc, os_strsignal(-rc), tmsg);
+      }
+    }
+
+  /* For positive values (process terminated with non-zero status), we need a
+  status code to request deferral. A number of systems contain the following
+  line in sysexits.h:
+
+      #define EX_TEMPFAIL 75
+
+  with the description
+
+      EX_TEMPFAIL -- temporary failure, indicating something that
+         is not really an error.  In sendmail, this means
+         that a mailer (e.g.) could not create a connection,
+         and the request should be reattempted later.
+
+  Based on this, we use exit code EX_TEMPFAIL as a default to mean "defer" when
+  not ignoring the returned status. However, there is now an option that
+  contains a list of temporary codes, with TEMPFAIL and CANTCREAT as defaults.
+
+  Another case that needs special treatment is if execve() failed (typically
+  the command that was given is a non-existent path). By default this is
+  treated as just another failure, but if freeze_exec_fail is set, the reaction
+  is to freeze the message rather than bounce the address. Exim used to signal
+  this failure with EX_UNAVAILABLE, which is defined in many systems as
+
+      #define EX_UNAVAILABLE  69
+
+  with the description
+
+      EX_UNAVAILABLE -- A service is unavailable.  This can occur
+            if a support program or file does not exist.  This
+            can also be used as a catchall message when something
+            you wanted to do doesn't work, but you don't know why.
+
+  However, this can be confused with a command that actually returns 69 because
+  something *it* wanted is unavailable. At release 4.21, Exim was changed to
+  use return code 127 instead, because this is what the shell returns when it
+  is unable to exec a command. We define it as EX_EXECFAILED, and use it in
+  child.c to signal execve() failure and other unexpected failures such as
+  setuid() not working - though that won't be the case here because we aren't
+  changing uid. */
+
+  else
+    {
+    /* Always handle execve() failure specially if requested to */
+
+    if (ob->freeze_exec_fail  &&  rc == EX_EXECFAILED)
+      {
+      addr->transport_return = DEFER;
+      addr->special_action = SPECIAL_FREEZE;
+      addr->message = string_sprintf("pipe process failed to exec \"%s\"%s",
+        cmd, tmsg);
+      }
+
+    /* Otherwise take action only if not ignoring status */
+
+    else if (!ob->ignore_status)
+      {
+      uschar *ss;
+      gstring * g;
+
+      /* If temp_errors is "*" all codes are temporary. Initialization checks
+      that it's either "*" or a list of numbers. If not "*", scan the list of
+      temporary failure codes; if any match, the result is DEFER. */
+
+      if (ob->temp_errors[0] == '*')
+        addr->transport_return = DEFER;
+
+      else
+        {
+        const uschar *s = ob->temp_errors;
+        uschar *p;
+        int sep = 0;
+
+        addr->transport_return = FAIL;
+        while ((p = string_nextinlist(&s,&sep,NULL,0)))
+          if (rc == Uatoi(p)) { addr->transport_return = DEFER; break; }
+        }
+
+      /* Ensure the message contains the expanded command and arguments. This
+      doesn't have to be brilliantly efficient - it is an error situation. */
+
+      addr->message = string_sprintf("Child process of %s transport returned "
+        "%d", tblock->name, rc);
+      g = string_cat(NULL, addr->message);
+
+      /* If the return code is > 128, it often means that a shell command
+      was terminated by a signal. */
+
+      ss = (rc > 128)?
+        string_sprintf("(could mean shell command ended by signal %d (%s))",
+          rc-128, os_strsignal(rc-128)) :
+        US os_strexit(rc);
+
+      if (*ss)
+        {
+        g = string_catn(g, US" ", 1);
+        g = string_cat (g, ss);
+        }
+
+      /* Now add the command and arguments */
+
+      g = string_catn(g, US" from command:", 14);
+
+      for (int i = 0; i < sizeof(argv)/sizeof(int *) && argv[i] != NULL; i++)
+        {
+        BOOL quote = FALSE;
+        g = string_catn(g, US" ", 1);
+        if (Ustrpbrk(argv[i], " \t") != NULL)
+          {
+          quote = TRUE;
+          g = string_catn(g, US"\"", 1);
+          }
+        g = string_cat(g, argv[i]);
+        if (quote)
+          g = string_catn(g, US"\"", 1);
+        }
+
+      /* Add previous filter timeout message, if present. */
+
+      if (*tmsg)
+        g = string_cat(g, tmsg);
+
+      addr->message = string_from_gstring(g);
+      }
+    }
+  }
+
+/* Ensure all subprocesses (in particular, the output handling process)
+are complete before we pass this point. */
+
+while (wait(&rc) >= 0);
+
+DEBUG(D_transport) debug_printf("%s transport yielded %d\n", tblock->name,
+  addr->transport_return);
+
+/* If there has been a problem, the message in addr->message contains details
+of the pipe command. We don't want to expose these to the world, so we set up
+something bland to return to the sender. */
+
+if (addr->transport_return != OK)
+  addr->user_message = US"local delivery failed";
+
+return FALSE;
+}
+
+#endif	/*!MACRO_PREDEF*/
+/* End of transport/pipe.c */
diff --git a/src/transports/pipe.h b/src/transports/pipe.h
new file mode 100644
index 0000000..ed5c142
--- /dev/null
+++ b/src/transports/pipe.h
@@ -0,0 +1,51 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+/* Copyright (c) University of Cambridge 1995 - 2014 */
+/* See the file NOTICE for conditions of use and distribution. */
+
+/* Private structure for the private options. */
+
+typedef struct {
+  uschar *cmd;
+  uschar *allow_commands;
+  uschar *environment;
+  uschar *path;
+  uschar *message_prefix;
+  uschar *message_suffix;
+  uschar *temp_errors;
+  uschar *check_string;
+  uschar *escape_string;
+  int   umask;
+  int   max_output;
+  int   timeout;
+  int   options;
+  BOOL  force_command;
+  BOOL  freeze_exec_fail;
+  BOOL  freeze_signal;
+  BOOL  ignore_status;
+  BOOL  permit_coredump;
+  BOOL  restrict_to_path;
+  BOOL  timeout_defer;
+  BOOL  use_shell;
+  BOOL  use_bsmtp;
+  BOOL  use_classresources;
+  BOOL  use_crlf;
+} pipe_transport_options_block;
+
+/* Data for reading the private options. */
+
+extern optionlist pipe_transport_options[];
+extern int pipe_transport_options_count;
+
+/* Block containing default values. */
+
+extern pipe_transport_options_block pipe_transport_option_defaults;
+
+/* The main and init entry points for the transport */
+
+extern BOOL pipe_transport_entry(transport_instance *, address_item *);
+extern void pipe_transport_init(transport_instance *);
+
+/* End of transports/pipe.h */
diff --git a/src/transports/queuefile.c b/src/transports/queuefile.c
new file mode 100644
index 0000000..9721854
--- /dev/null
+++ b/src/transports/queuefile.c
@@ -0,0 +1,282 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+/* Copyright (c) Andrew Colin Kissa <andrew@topdog.za.net> 2016 */
+/* Copyright (c) University of Cambridge 2016 */
+/* Copyright (c) The Exim Maintainers 1995 - 2020 */
+/* See the file NOTICE for conditions of use and distribution. */
+
+
+
+#include "../exim.h"
+
+#ifdef EXPERIMENTAL_QUEUEFILE	/* whole file */
+#include "queuefile.h"
+
+/* Options specific to the appendfile transport. They must be in alphabetic
+order (note that "_" comes before the lower case letters). Some of them are
+stored in the publicly visible instance block - these are flagged with the
+opt_public flag. */
+
+optionlist queuefile_transport_options[] = {
+  { "directory", opt_stringptr,
+    OPT_OFF(queuefile_transport_options_block, dirname) },
+};
+
+
+/* Size of the options list. An extern variable has to be used so that its
+address can appear in the tables drtables.c. */
+
+int queuefile_transport_options_count =
+  sizeof(queuefile_transport_options) / sizeof(optionlist);
+
+
+#ifdef MACRO_PREDEF
+
+/* Dummy values */
+queuefile_transport_options_block queuefile_transport_option_defaults = {0};
+void queuefile_transport_init(transport_instance *tblock) {}
+BOOL queuefile_transport_entry(transport_instance *tblock, address_item *addr) {return FALSE;}
+
+#else   /*!MACRO_PREDEF*/
+
+
+
+/* Default private options block for the appendfile transport. */
+
+queuefile_transport_options_block queuefile_transport_option_defaults = {
+  NULL,           /* dirname */
+};
+
+/*************************************************
+*          Initialization entry point            *
+*************************************************/
+
+void queuefile_transport_init(transport_instance *tblock)
+{
+queuefile_transport_options_block *ob =
+  (queuefile_transport_options_block *) tblock->options_block;
+
+if (!ob->dirname)
+  log_write(0, LOG_PANIC_DIE | LOG_CONFIG,
+    "directory must be set for the %s transport", tblock->name);
+}
+
+/* This function will copy from a file to another
+
+Arguments:
+  dst        fd to write to (the destination queue file)
+  src        fd to read from (the spool queue file)
+
+Returns:       TRUE if all went well, FALSE otherwise with errno set
+*/
+
+static BOOL
+copy_spool_file(int dst, int src)
+{
+int i, j;
+uschar buffer[16384];
+
+if (lseek(src, 0, SEEK_SET) != 0)
+  return FALSE;
+
+do
+  if ((j = read(src, buffer, sizeof(buffer))) > 0)
+    for (uschar * s = buffer; (i = write(dst, s, j)) != j; s += i, j -= i)
+      if (i < 0)
+	return FALSE;
+  else if (j < 0)
+    return FALSE;
+while (j > 0);
+return TRUE;
+}
+
+/* This function performs the actual copying of the header
+and data files to the destination directory
+
+Arguments:
+  tb		the transport block
+  addr          address_item being processed
+  dstpath	destination directory name
+  sdfd          int Source directory fd
+  ddfd          int Destination directory fd
+  link_file     BOOL use linkat instead of data copy
+  srcfd		fd for data file, or -1 for header file
+
+Returns:       TRUE if all went well, FALSE otherwise
+*/
+
+static BOOL
+copy_spool_files(transport_instance * tb, address_item * addr,
+  const uschar * dstpath, int sdfd, int ddfd, BOOL link_file, int srcfd)
+{
+BOOL is_hdr_file = srcfd < 0;
+const uschar * suffix = srcfd < 0 ? US"H" : US"D";
+int dstfd;
+const uschar * filename = string_sprintf("%s-%s", message_id, suffix);
+const uschar * srcpath = spool_fname(US"input", message_subdir, message_id, suffix);
+const uschar * s, * op;
+
+dstpath = string_sprintf("%s/%s-%s", dstpath, message_id, suffix);
+
+if (link_file)
+  {
+  DEBUG(D_transport) debug_printf("%s transport, linking %s => %s\n",
+    tb->name, srcpath, dstpath);
+
+  if (linkat(sdfd, CCS filename, ddfd, CCS filename, 0) >= 0)
+    return TRUE;
+
+  op = US"linking";
+  s = dstpath;
+  }
+else					/* use data copy */
+  {
+  DEBUG(D_transport) debug_printf("%s transport, copying %s => %s\n",
+    tb->name, srcpath, dstpath);
+
+  if (  (s = dstpath,
+	 (dstfd = exim_openat4(ddfd, CCS filename, O_RDWR|O_CREAT|O_EXCL, SPOOL_MODE))
+	 < 0
+	)
+     ||    is_hdr_file
+	&& (s = srcpath, (srcfd = exim_openat(sdfd, CCS filename, O_RDONLY)) < 0)
+     )
+    op = US"opening";
+
+  else
+    if (s = dstpath, fchmod(dstfd, SPOOL_MODE) != 0)
+      op = US"setting perms on";
+    else
+      if (!copy_spool_file(dstfd, srcfd))
+	op = US"creating";
+      else
+	return TRUE;
+  }
+
+addr->basic_errno = errno;
+addr->message = string_sprintf("%s transport %s file: %s failed with error: %s",
+  tb->name, op, s, strerror(errno));
+addr->transport_return = DEFER;
+return FALSE;
+}
+
+/*************************************************
+*              Main entry point                  *
+*************************************************/
+
+/* This transport always returns FALSE, indicating that the status in
+the first address is the status for all addresses in a batch. */
+
+BOOL
+queuefile_transport_entry(transport_instance * tblock, address_item * addr)
+{
+queuefile_transport_options_block * ob =
+  (queuefile_transport_options_block *) tblock->options_block;
+BOOL can_link;
+uschar * sourcedir = spool_dname(US"input", message_subdir);
+uschar * s, * dstdir;
+struct stat dstatbuf, sstatbuf;
+int ddfd = -1, sdfd = -1;
+
+DEBUG(D_transport)
+  debug_printf("%s transport entered\n", tblock->name);
+
+#ifndef O_DIRECTORY
+# define O_DIRECTORY 0
+#endif
+#ifndef O_NOFOLLOW
+# define O_NOFOLLOW 0
+#endif
+
+if (!(dstdir = expand_string(ob->dirname)))
+  {
+  addr->message = string_sprintf("%s transport: failed to expand dirname option",
+    tblock->name);
+  addr->transport_return = DEFER;
+  return FALSE;
+  }
+if (*dstdir != '/')
+  {
+  addr->transport_return = PANIC;
+  addr->message = string_sprintf("%s transport directory: "
+    "%s is not absolute", tblock->name, dstdir);
+  return FALSE;
+  }
+
+/* Open the source and destination directories and check if they are
+on the same filesystem, so we can hard-link files rather than copying. */
+
+if (  (s = dstdir,
+       (ddfd = Uopen(s, O_RDONLY | O_DIRECTORY | O_NOFOLLOW, 0)) < 0)
+   || (s = sourcedir,
+       (sdfd = Uopen(sourcedir, O_RDONLY | O_DIRECTORY | O_NOFOLLOW, 0)) < 0)
+   )
+  {
+  addr->transport_return = PANIC;
+  addr->basic_errno = errno;
+  addr->message = string_sprintf("%s transport accessing directory: %s "
+    "failed with error: %s", tblock->name, s, strerror(errno));
+  if (ddfd >= 0) (void) close(ddfd);
+  return FALSE;
+  }
+
+if (  (s = dstdir,    fstat(ddfd, &dstatbuf) < 0)
+   || (s = sourcedir, fstat(sdfd, &sstatbuf) < 0)
+   )
+  {
+  addr->transport_return = PANIC;
+  addr->basic_errno = errno;
+  addr->message = string_sprintf("%s transport fstat on directory fd: "
+    "%s failed with error: %s", tblock->name, s, strerror(errno));
+  goto RETURN;
+  }
+can_link = (dstatbuf.st_dev == sstatbuf.st_dev);
+
+if (f.dont_deliver)
+  {
+  DEBUG(D_transport)
+    debug_printf("*** delivery by %s transport bypassed by -N option\n",
+      tblock->name);
+  addr->transport_return = OK;
+  goto RETURN;
+  }
+
+/* Link or copy the header and data spool files */
+
+DEBUG(D_transport)
+  debug_printf("%s transport, copying header file\n", tblock->name);
+
+if (!copy_spool_files(tblock, addr, dstdir, sdfd, ddfd, can_link, -1))
+  goto RETURN;
+
+DEBUG(D_transport)
+  debug_printf("%s transport, copying data file\n", tblock->name);
+
+if (!copy_spool_files(tblock, addr, dstdir, sdfd, ddfd, can_link,
+	deliver_datafile))
+  {
+  DEBUG(D_transport)
+    debug_printf("%s transport, copying data file failed, "
+      "unlinking the header file\n", tblock->name);
+  Uunlink(string_sprintf("%s/%s-H", dstdir, message_id));
+  goto RETURN;
+  }
+
+DEBUG(D_transport)
+  debug_printf("%s transport succeeded\n", tblock->name);
+
+addr->transport_return = OK;
+
+RETURN:
+if (ddfd >= 0) (void) close(ddfd);
+if (sdfd >= 0) (void) close(sdfd);
+
+/* A return of FALSE means that if there was an error, a common error was
+put in the first address of a batch. */
+return FALSE;
+}
+
+#endif /*!MACRO_PREDEF*/
+#endif /*EXPERIMENTAL_QUEUEFILE*/
diff --git a/src/transports/queuefile.h b/src/transports/queuefile.h
new file mode 100644
index 0000000..0e45b51
--- /dev/null
+++ b/src/transports/queuefile.h
@@ -0,0 +1,29 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+/* Copyright (c) Andrew Colin Kissa <andrew@topdog.za.net> 2016 */
+/* Copyright (c) University of Cambridge 2016 */
+/* See the file NOTICE for conditions of use and distribution. */
+
+/* Private structure for the private options. */
+
+typedef struct {
+    uschar *dirname;
+} queuefile_transport_options_block;
+
+/* Data for reading the private options. */
+
+extern optionlist queuefile_transport_options[];
+extern int queuefile_transport_options_count;
+
+/* Block containing default values. */
+
+extern queuefile_transport_options_block queuefile_transport_option_defaults;
+
+/* The main and init entry points for the transport */
+
+extern BOOL queuefile_transport_entry(transport_instance *, address_item *);
+extern void queuefile_transport_init(transport_instance *);
+
+/* End of transports/queuefile.h */
diff --git a/src/transports/smtp.c b/src/transports/smtp.c
new file mode 100644
index 0000000..f26e233
--- /dev/null
+++ b/src/transports/smtp.c
@@ -0,0 +1,5640 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+/* Copyright (c) University of Cambridge 1995 - 2018 */
+/* Copyright (c) The Exim Maintainers 2020 */
+/* See the file NOTICE for conditions of use and distribution. */
+
+#include "../exim.h"
+#include "smtp.h"
+
+#if defined(SUPPORT_DANE) && defined(DISABLE_TLS)
+# error TLS is required for DANE
+#endif
+
+
+/* Options specific to the smtp transport. This transport also supports LMTP
+over TCP/IP. The options must be in alphabetic order (note that "_" comes
+before the lower case letters). Some live in the transport_instance block so as
+to be publicly visible; these are flagged with opt_public. */
+
+#define LOFF(field) OPT_OFF(smtp_transport_options_block, field)
+
+optionlist smtp_transport_options[] = {
+  { "*expand_multi_domain",             opt_stringptr | opt_hidden | opt_public,
+      OPT_OFF(transport_instance, expand_multi_domain) },
+  { "*expand_retry_include_ip_address", opt_stringptr | opt_hidden,
+      LOFF(expand_retry_include_ip_address) },
+
+  { "address_retry_include_sender", opt_bool,
+      LOFF(address_retry_include_sender) },
+  { "allow_localhost",      opt_bool,	   LOFF(allow_localhost) },
+#ifdef EXPERIMENTAL_ARC
+  { "arc_sign", opt_stringptr,		   LOFF(arc_sign) },
+#endif
+  { "authenticated_sender", opt_stringptr, LOFF(authenticated_sender) },
+  { "authenticated_sender_force", opt_bool, LOFF(authenticated_sender_force) },
+  { "command_timeout",      opt_time,	   LOFF(command_timeout) },
+  { "connect_timeout",      opt_time,	   LOFF(connect_timeout) },
+  { "connection_max_messages", opt_int | opt_public,
+      OPT_OFF(transport_instance, connection_max_messages) },
+# ifdef SUPPORT_DANE
+  { "dane_require_tls_ciphers", opt_stringptr, LOFF(dane_require_tls_ciphers) },
+# endif
+  { "data_timeout",         opt_time,	   LOFF(data_timeout) },
+  { "delay_after_cutoff", opt_bool,	   LOFF(delay_after_cutoff) },
+#ifndef DISABLE_DKIM
+  { "dkim_canon", opt_stringptr,	   LOFF(dkim.dkim_canon) },
+  { "dkim_domain", opt_stringptr,	   LOFF(dkim.dkim_domain) },
+  { "dkim_hash", opt_stringptr,		   LOFF(dkim.dkim_hash) },
+  { "dkim_identity", opt_stringptr,	   LOFF(dkim.dkim_identity) },
+  { "dkim_private_key", opt_stringptr,	   LOFF(dkim.dkim_private_key) },
+  { "dkim_selector", opt_stringptr,	   LOFF(dkim.dkim_selector) },
+  { "dkim_sign_headers", opt_stringptr,	   LOFF(dkim.dkim_sign_headers) },
+  { "dkim_strict", opt_stringptr,	   LOFF(dkim.dkim_strict) },
+  { "dkim_timestamps", opt_stringptr,	   LOFF(dkim.dkim_timestamps) },
+#endif
+  { "dns_qualify_single",   opt_bool,	   LOFF(dns_qualify_single) },
+  { "dns_search_parents",   opt_bool,	   LOFF(dns_search_parents) },
+  { "dnssec_request_domains", opt_stringptr, LOFF(dnssec.request) },
+  { "dnssec_require_domains", opt_stringptr, LOFF(dnssec.require) },
+  { "dscp",                 opt_stringptr, LOFF(dscp) },
+  { "fallback_hosts",       opt_stringptr, LOFF(fallback_hosts) },
+  { "final_timeout",        opt_time,	   LOFF(final_timeout) },
+  { "gethostbyname",        opt_bool,	   LOFF(gethostbyname) },
+  { "helo_data",            opt_stringptr, LOFF(helo_data) },
+  { "hosts",                opt_stringptr, LOFF(hosts) },
+  { "hosts_avoid_esmtp",    opt_stringptr, LOFF(hosts_avoid_esmtp) },
+  { "hosts_avoid_pipelining", opt_stringptr, LOFF(hosts_avoid_pipelining) },
+#ifndef DISABLE_TLS
+  { "hosts_avoid_tls",      opt_stringptr, LOFF(hosts_avoid_tls) },
+#endif
+  { "hosts_max_try",        opt_int,	   LOFF(hosts_max_try) },
+  { "hosts_max_try_hardlimit", opt_int,	   LOFF(hosts_max_try_hardlimit) },
+#ifndef DISABLE_TLS
+  { "hosts_nopass_tls",     opt_stringptr, LOFF(hosts_nopass_tls) },
+  { "hosts_noproxy_tls",    opt_stringptr, LOFF(hosts_noproxy_tls) },
+#endif
+  { "hosts_override",       opt_bool,	   LOFF(hosts_override) },
+#ifndef DISABLE_PIPE_CONNECT
+  { "hosts_pipe_connect",   opt_stringptr, LOFF(hosts_pipe_connect) },
+#endif
+  { "hosts_randomize",      opt_bool,	   LOFF(hosts_randomize) },
+#if !defined(DISABLE_TLS) && !defined(DISABLE_OCSP)
+  { "hosts_request_ocsp",   opt_stringptr, LOFF(hosts_request_ocsp) },
+#endif
+  { "hosts_require_auth",   opt_stringptr, LOFF(hosts_require_auth) },
+#ifndef DISABLE_TLS
+# ifdef SUPPORT_DANE
+  { "hosts_require_dane",   opt_stringptr, LOFF(hosts_require_dane) },
+# endif
+# ifndef DISABLE_OCSP
+  { "hosts_require_ocsp",   opt_stringptr, LOFF(hosts_require_ocsp) },
+# endif
+  { "hosts_require_tls",    opt_stringptr, LOFF(hosts_require_tls) },
+#endif
+  { "hosts_try_auth",       opt_stringptr, LOFF(hosts_try_auth) },
+  { "hosts_try_chunking",   opt_stringptr, LOFF(hosts_try_chunking) },
+#ifdef SUPPORT_DANE
+  { "hosts_try_dane",       opt_stringptr, LOFF(hosts_try_dane) },
+#endif
+  { "hosts_try_fastopen",   opt_stringptr, LOFF(hosts_try_fastopen) },
+#ifndef DISABLE_PRDR
+  { "hosts_try_prdr",       opt_stringptr, LOFF(hosts_try_prdr) },
+#endif
+#ifndef DISABLE_TLS
+  { "hosts_verify_avoid_tls", opt_stringptr, LOFF(hosts_verify_avoid_tls) },
+#endif
+  { "interface",            opt_stringptr, LOFF(interface) },
+  { "keepalive",            opt_bool,	   LOFF(keepalive) },
+  { "lmtp_ignore_quota",    opt_bool,	   LOFF(lmtp_ignore_quota) },
+  { "max_rcpt",             opt_int | opt_public,
+      OPT_OFF(transport_instance, max_addresses) },
+  { "multi_domain",         opt_expand_bool | opt_public,
+      OPT_OFF(transport_instance, multi_domain) },
+  { "port",                 opt_stringptr, LOFF(port) },
+  { "protocol",             opt_stringptr, LOFF(protocol) },
+  { "retry_include_ip_address", opt_expand_bool, LOFF(retry_include_ip_address) },
+  { "serialize_hosts",      opt_stringptr, LOFF(serialize_hosts) },
+  { "size_addition",        opt_int,	   LOFF(size_addition) },
+#ifdef SUPPORT_SOCKS
+  { "socks_proxy",          opt_stringptr, LOFF(socks_proxy) },
+#endif
+#ifndef DISABLE_TLS
+  { "tls_certificate",      opt_stringptr, LOFF(tls_certificate) },
+  { "tls_crl",              opt_stringptr, LOFF(tls_crl) },
+  { "tls_dh_min_bits",      opt_int,	   LOFF(tls_dh_min_bits) },
+  { "tls_privatekey",       opt_stringptr, LOFF(tls_privatekey) },
+  { "tls_require_ciphers",  opt_stringptr, LOFF(tls_require_ciphers) },
+# ifdef EXPERIMENTAL_TLS_RESUME
+  { "tls_resumption_hosts", opt_stringptr, LOFF(tls_resumption_hosts) },
+# endif
+  { "tls_sni",              opt_stringptr, LOFF(tls_sni) },
+  { "tls_tempfail_tryclear", opt_bool, LOFF(tls_tempfail_tryclear) },
+  { "tls_try_verify_hosts", opt_stringptr, LOFF(tls_try_verify_hosts) },
+  { "tls_verify_cert_hostnames", opt_stringptr, LOFF(tls_verify_cert_hostnames)},
+  { "tls_verify_certificates", opt_stringptr, LOFF(tls_verify_certificates) },
+  { "tls_verify_hosts",     opt_stringptr, LOFF(tls_verify_hosts) },
+#endif
+#ifdef SUPPORT_I18N
+  { "utf8_downconvert",	    opt_stringptr, LOFF(utf8_downconvert) },
+#endif
+};
+
+/* Size of the options list. An extern variable has to be used so that its
+address can appear in the tables drtables.c. */
+
+int smtp_transport_options_count = nelem(smtp_transport_options);
+
+
+#ifdef MACRO_PREDEF
+
+/* Dummy values */
+smtp_transport_options_block smtp_transport_option_defaults = {0};
+void smtp_transport_init(transport_instance *tblock) {}
+BOOL smtp_transport_entry(transport_instance *tblock, address_item *addr) {return FALSE;}
+void smtp_transport_closedown(transport_instance *tblock) {}
+
+#else   /*!MACRO_PREDEF*/
+
+
+/* Default private options block for the smtp transport. */
+
+smtp_transport_options_block smtp_transport_option_defaults = {
+  .hosts =			NULL,
+  .fallback_hosts =		NULL,
+  .hostlist =			NULL,
+  .fallback_hostlist =		NULL,
+  .helo_data =			US"$primary_hostname",
+  .interface =			NULL,
+  .port =			NULL,
+  .protocol =			US"smtp",
+  .dscp =			NULL,
+  .serialize_hosts =		NULL,
+  .hosts_try_auth =		NULL,
+  .hosts_require_auth =		NULL,
+  .hosts_try_chunking =		US"*",
+#ifdef SUPPORT_DANE
+  .hosts_try_dane =		US"*",
+  .hosts_require_dane =		NULL,
+  .dane_require_tls_ciphers =	NULL,
+#endif
+  .hosts_try_fastopen =		US"*",
+#ifndef DISABLE_PRDR
+  .hosts_try_prdr =		US"*",
+#endif
+#ifndef DISABLE_OCSP
+  .hosts_request_ocsp =		US"*",               /* hosts_request_ocsp (except under DANE; tls_client_start()) */
+  .hosts_require_ocsp =		NULL,
+#endif
+  .hosts_require_tls =		NULL,
+  .hosts_avoid_tls =		NULL,
+  .hosts_verify_avoid_tls =	NULL,
+  .hosts_avoid_pipelining =	NULL,
+#ifndef DISABLE_PIPE_CONNECT
+  .hosts_pipe_connect =		NULL,
+#endif
+  .hosts_avoid_esmtp =		NULL,
+#ifndef DISABLE_TLS
+  .hosts_nopass_tls =		NULL,
+  .hosts_noproxy_tls =		NULL,
+#endif
+  .command_timeout =		5*60,
+  .connect_timeout =		5*60,
+  .data_timeout =		5*60,
+  .final_timeout =		10*60,
+  .size_addition =		1024,
+  .hosts_max_try =		5,
+  .hosts_max_try_hardlimit =	50,
+  .address_retry_include_sender = TRUE,
+  .allow_localhost =		FALSE,
+  .authenticated_sender_force =	FALSE,
+  .gethostbyname =		FALSE,
+  .dns_qualify_single =		TRUE,
+  .dns_search_parents =		FALSE,
+  .dnssec = { .request= US"*", .require=NULL },
+  .delay_after_cutoff =		TRUE,
+  .hosts_override =		FALSE,
+  .hosts_randomize =		FALSE,
+  .keepalive =			TRUE,
+  .lmtp_ignore_quota =		FALSE,
+  .expand_retry_include_ip_address =	NULL,
+  .retry_include_ip_address =	TRUE,
+#ifdef SUPPORT_SOCKS
+  .socks_proxy =		NULL,
+#endif
+#ifndef DISABLE_TLS
+  .tls_certificate =		NULL,
+  .tls_crl =			NULL,
+  .tls_privatekey =		NULL,
+  .tls_require_ciphers =	NULL,
+  .tls_sni =			NULL,
+  .tls_verify_certificates =	US"system",
+  .tls_dh_min_bits =		EXIM_CLIENT_DH_DEFAULT_MIN_BITS,
+  .tls_tempfail_tryclear =	TRUE,
+# ifdef EXPERIMENTAL_TLS_RESUME
+  .tls_resumption_hosts =	NULL,
+# endif
+  .tls_verify_hosts =		NULL,
+  .tls_try_verify_hosts =	US"*",
+  .tls_verify_cert_hostnames =	US"*",
+#endif
+#ifdef SUPPORT_I18N
+  .utf8_downconvert =		US"-1",
+#endif
+#ifndef DISABLE_DKIM
+ .dkim =
+   {.dkim_domain =		NULL,
+    .dkim_identity =		NULL,
+    .dkim_private_key =		NULL,
+    .dkim_selector =		NULL,
+    .dkim_canon =		NULL,
+    .dkim_sign_headers =	NULL,
+    .dkim_strict =		NULL,
+    .dkim_hash =		US"sha256",
+    .dkim_timestamps =		NULL,
+    .dot_stuffed =		FALSE,
+    .force_bodyhash =		FALSE,
+# ifdef EXPERIMENTAL_ARC
+    .arc_signspec =		NULL,
+# endif
+    },
+# ifdef EXPERIMENTAL_ARC
+  .arc_sign =			NULL,
+# endif
+#endif
+};
+
+/* some DSN flags for use later */
+
+static int     rf_list[] = {rf_notify_never, rf_notify_success,
+                            rf_notify_failure, rf_notify_delay };
+
+static uschar *rf_names[] = { US"NEVER", US"SUCCESS", US"FAILURE", US"DELAY" };
+
+
+
+/* Local statics */
+
+static uschar *smtp_command;		/* Points to last cmd for error messages */
+static uschar *mail_command;		/* Points to MAIL cmd for error messages */
+static uschar *data_command = US"";	/* Points to DATA cmd for error messages */
+static BOOL    update_waiting;		/* TRUE to update the "wait" database */
+
+/*XXX move to smtp_context */
+static BOOL    pipelining_active;	/* current transaction is in pipe mode */
+
+
+static unsigned ehlo_response(uschar * buf, unsigned checks);
+
+
+/******************************************************************************/
+
+void
+smtp_deliver_init(void)
+{
+if (!regex_PIPELINING) regex_PIPELINING =
+  regex_must_compile(US"\\n250[\\s\\-]PIPELINING(\\s|\\n|$)", FALSE, TRUE);
+
+if (!regex_SIZE) regex_SIZE =
+  regex_must_compile(US"\\n250[\\s\\-]SIZE(\\s|\\n|$)", FALSE, TRUE);
+
+if (!regex_AUTH) regex_AUTH =
+  regex_must_compile(AUTHS_REGEX, FALSE, TRUE);
+
+#ifndef DISABLE_TLS
+if (!regex_STARTTLS) regex_STARTTLS =
+  regex_must_compile(US"\\n250[\\s\\-]STARTTLS(\\s|\\n|$)", FALSE, TRUE);
+#endif
+
+if (!regex_CHUNKING) regex_CHUNKING =
+  regex_must_compile(US"\\n250[\\s\\-]CHUNKING(\\s|\\n|$)", FALSE, TRUE);
+
+#ifndef DISABLE_PRDR
+if (!regex_PRDR) regex_PRDR =
+  regex_must_compile(US"\\n250[\\s\\-]PRDR(\\s|\\n|$)", FALSE, TRUE);
+#endif
+
+#ifdef SUPPORT_I18N
+if (!regex_UTF8) regex_UTF8 =
+  regex_must_compile(US"\\n250[\\s\\-]SMTPUTF8(\\s|\\n|$)", FALSE, TRUE);
+#endif
+
+if (!regex_DSN) regex_DSN  =
+  regex_must_compile(US"\\n250[\\s\\-]DSN(\\s|\\n|$)", FALSE, TRUE);
+
+if (!regex_IGNOREQUOTA) regex_IGNOREQUOTA =
+  regex_must_compile(US"\\n250[\\s\\-]IGNOREQUOTA(\\s|\\n|$)", FALSE, TRUE);
+
+#ifndef DISABLE_PIPE_CONNECT
+if (!regex_EARLY_PIPE) regex_EARLY_PIPE =
+  regex_must_compile(US"\\n250[\\s\\-]" EARLY_PIPE_FEATURE_NAME "(\\s|\\n|$)", FALSE, TRUE);
+#endif
+}
+
+
+/*************************************************
+*             Setup entry point                  *
+*************************************************/
+
+/* This function is called when the transport is about to be used,
+but before running it in a sub-process. It is used for two things:
+
+  (1) To set the fallback host list in addresses, when delivering.
+  (2) To pass back the interface, port, protocol, and other options, for use
+      during callout verification.
+
+Arguments:
+  tblock    pointer to the transport instance block
+  addrlist  list of addresses about to be transported
+  tf        if not NULL, pointer to block in which to return options
+  uid       the uid that will be set (not used)
+  gid       the gid that will be set (not used)
+  errmsg    place for error message (not used)
+
+Returns:  OK always (FAIL, DEFER not used)
+*/
+
+static int
+smtp_transport_setup(transport_instance *tblock, address_item *addrlist,
+  transport_feedback *tf, uid_t uid, gid_t gid, uschar **errmsg)
+{
+smtp_transport_options_block *ob = SOB tblock->options_block;
+
+errmsg = errmsg;    /* Keep picky compilers happy */
+uid = uid;
+gid = gid;
+
+/* Pass back options if required. This interface is getting very messy. */
+
+if (tf)
+  {
+  tf->interface = ob->interface;
+  tf->port = ob->port;
+  tf->protocol = ob->protocol;
+  tf->hosts = ob->hosts;
+  tf->hosts_override = ob->hosts_override;
+  tf->hosts_randomize = ob->hosts_randomize;
+  tf->gethostbyname = ob->gethostbyname;
+  tf->qualify_single = ob->dns_qualify_single;
+  tf->search_parents = ob->dns_search_parents;
+  tf->helo_data = ob->helo_data;
+  }
+
+/* Set the fallback host list for all the addresses that don't have fallback
+host lists, provided that the local host wasn't present in the original host
+list. */
+
+if (!testflag(addrlist, af_local_host_removed))
+  for (; addrlist; addrlist = addrlist->next)
+    if (!addrlist->fallback_hosts) addrlist->fallback_hosts = ob->fallback_hostlist;
+
+return OK;
+}
+
+
+
+/*************************************************
+*          Initialization entry point            *
+*************************************************/
+
+/* Called for each instance, after its options have been read, to
+enable consistency checks to be done, or anything else that needs
+to be set up.
+
+Argument:   pointer to the transport instance block
+Returns:    nothing
+*/
+
+void
+smtp_transport_init(transport_instance *tblock)
+{
+smtp_transport_options_block *ob = SOB tblock->options_block;
+
+/* Retry_use_local_part defaults FALSE if unset */
+
+if (tblock->retry_use_local_part == TRUE_UNSET)
+  tblock->retry_use_local_part = FALSE;
+
+/* Set the default port according to the protocol */
+
+if (!ob->port)
+  ob->port = strcmpic(ob->protocol, US"lmtp") == 0
+  ? US"lmtp"
+  : strcmpic(ob->protocol, US"smtps") == 0
+  ? US"smtps" : US"smtp";
+
+/* Set up the setup entry point, to be called before subprocesses for this
+transport. */
+
+tblock->setup = smtp_transport_setup;
+
+/* Complain if any of the timeouts are zero. */
+
+if (ob->command_timeout <= 0 || ob->data_timeout <= 0 ||
+    ob->final_timeout <= 0)
+  log_write(0, LOG_PANIC_DIE|LOG_CONFIG,
+    "command, data, or final timeout value is zero for %s transport",
+      tblock->name);
+
+/* If hosts_override is set and there are local hosts, set the global
+flag that stops verify from showing router hosts. */
+
+if (ob->hosts_override && ob->hosts != NULL) tblock->overrides_hosts = TRUE;
+
+/* If there are any fallback hosts listed, build a chain of host items
+for them, but do not do any lookups at this time. */
+
+host_build_hostlist(&(ob->fallback_hostlist), ob->fallback_hosts, FALSE);
+}
+
+
+
+
+
+/*************************************************
+*   Set delivery info into all active addresses  *
+*************************************************/
+
+/* Only addresses whose status is >= PENDING are relevant. A lesser
+status means that an address is not currently being processed.
+
+Arguments:
+  addrlist       points to a chain of addresses
+  errno_value    to put in each address's errno field
+  msg            to put in each address's message field
+  rc             to put in each address's transport_return field
+  pass_message   if TRUE, set the "pass message" flag in the address
+  host           if set, mark addrs as having used this host
+  smtp_greeting  from peer
+  helo_response  from peer
+  start		 points to timestamp of delivery start
+
+If errno_value has the special value ERRNO_CONNECTTIMEOUT, ETIMEDOUT is put in
+the errno field, and RTEF_CTOUT is ORed into the more_errno field, to indicate
+this particular type of timeout.
+
+Returns:       nothing
+*/
+
+static void
+set_errno(address_item *addrlist, int errno_value, uschar *msg, int rc,
+  BOOL pass_message, host_item * host,
+#ifdef EXPERIMENTAL_DSN_INFO
+  const uschar * smtp_greeting, const uschar * helo_response,
+#endif
+  struct timeval * start
+  )
+{
+int orvalue = 0;
+struct timeval deliver_time;
+
+if (errno_value == ERRNO_CONNECTTIMEOUT)
+  {
+  errno_value = ETIMEDOUT;
+  orvalue = RTEF_CTOUT;
+  }
+timesince(&deliver_time, start);
+
+for (address_item * addr = addrlist; addr; addr = addr->next)
+  if (addr->transport_return >= PENDING)
+    {
+    addr->basic_errno = errno_value;
+    addr->more_errno |= orvalue;
+    addr->delivery_time = deliver_time;
+    if (msg)
+      {
+      addr->message = msg;
+      if (pass_message) setflag(addr, af_pass_message);
+      }
+    addr->transport_return = rc;
+    if (host)
+      {
+      addr->host_used = host;
+#ifdef EXPERIMENTAL_DSN_INFO
+      if (smtp_greeting)
+	{uschar * s = Ustrchr(smtp_greeting, '\n'); if (s) *s = '\0';}
+      addr->smtp_greeting = smtp_greeting;
+
+      if (helo_response)
+	{uschar * s = Ustrchr(helo_response, '\n'); if (s) *s = '\0';}
+      addr->helo_response = helo_response;
+#endif
+      }
+    }
+}
+
+static void
+set_errno_nohost(address_item * addrlist, int errno_value, uschar * msg, int rc,
+  BOOL pass_message, struct timeval * start)
+{
+set_errno(addrlist, errno_value, msg, rc, pass_message, NULL,
+#ifdef EXPERIMENTAL_DSN_INFO
+	  NULL, NULL,
+#endif
+	  start);
+}
+
+
+/*************************************************
+*          Check an SMTP response                *
+*************************************************/
+
+/* This function is given an errno code and the SMTP response buffer
+to analyse, together with the host identification for generating messages. It
+sets an appropriate message and puts the first digit of the response code into
+the yield variable. If no response was actually read, a suitable digit is
+chosen.
+
+Arguments:
+  host           the current host, to get its name for messages
+  errno_value    pointer to the errno value
+  more_errno     from the top address for use with ERRNO_FILTER_FAIL
+  buffer         the SMTP response buffer
+  yield          where to put a one-digit SMTP response code
+  message        where to put an error message
+  pass_message   set TRUE if message is an SMTP response
+
+Returns:         TRUE if an SMTP "QUIT" command should be sent, else FALSE
+*/
+
+static BOOL
+check_response(host_item *host, int *errno_value, int more_errno,
+  uschar *buffer, int *yield, uschar **message, BOOL *pass_message)
+{
+uschar * pl = pipelining_active ? US"pipelined " : US"";
+const uschar * s;
+
+*yield = '4';    /* Default setting is to give a temporary error */
+
+switch(*errno_value)
+  {
+  case ETIMEDOUT:		/* Handle response timeout */
+    *message = US string_sprintf("SMTP timeout after %s%s",
+	pl, smtp_command);
+    if (transport_count > 0)
+      *message = US string_sprintf("%s (%d bytes written)", *message,
+	transport_count);
+    return FALSE;
+
+  case ERRNO_SMTPFORMAT:	/* Handle malformed SMTP response */
+    s = string_printing(buffer);
+    while (isspace(*s)) s++;
+    *message = *s == 0
+      ? string_sprintf("Malformed SMTP reply (an empty line) "
+	  "in response to %s%s", pl, smtp_command)
+      : string_sprintf("Malformed SMTP reply in response to %s%s: %s",
+	  pl, smtp_command, s);
+    return FALSE;
+
+  case ERRNO_TLSFAILURE:	/* Handle bad first read; can happen with
+				GnuTLS and TLS1.3 */
+    *message = US"bad first read from TLS conn";
+    return TRUE;
+
+  case ERRNO_FILTER_FAIL:	/* Handle a failed filter process error;
+			  can't send QUIT as we mustn't end the DATA. */
+    *message = string_sprintf("transport filter process failed (%d)%s",
+      more_errno,
+      more_errno == EX_EXECFAILED ? ": unable to execute command" : "");
+    return FALSE;
+
+  case ERRNO_CHHEADER_FAIL:	/* Handle a failed add_headers expansion;
+			    can't send QUIT as we mustn't end the DATA. */
+    *message =
+      string_sprintf("failed to expand headers_add or headers_remove: %s",
+	expand_string_message);
+    return FALSE;
+
+  case ERRNO_WRITEINCOMPLETE:	/* failure to write a complete data block */
+    *message = US"failed to write a data block";
+    return FALSE;
+
+#ifdef SUPPORT_I18N
+  case ERRNO_UTF8_FWD: /* no advertised SMTPUTF8, for international message */
+    *message = US"utf8 support required but not offered for forwarding";
+    DEBUG(D_deliver|D_transport) debug_printf("%s\n", *message);
+    return TRUE;
+#endif
+  }
+
+/* Handle error responses from the remote mailer. */
+
+if (buffer[0] != 0)
+  {
+  *message = string_sprintf("SMTP error from remote mail server after %s%s: "
+    "%s", pl, smtp_command, s = string_printing(buffer));
+  *pass_message = TRUE;
+  *yield = buffer[0];
+  return TRUE;
+  }
+
+/* No data was read. If there is no errno, this must be the EOF (i.e.
+connection closed) case, which causes deferral. An explicit connection reset
+error has the same effect. Otherwise, put the host's identity in the message,
+leaving the errno value to be interpreted as well. In all cases, we have to
+assume the connection is now dead. */
+
+if (*errno_value == 0 || *errno_value == ECONNRESET)
+  {
+  *errno_value = ERRNO_SMTPCLOSED;
+  *message = US string_sprintf("Remote host closed connection "
+    "in response to %s%s", pl, smtp_command);
+  }
+else
+  *message = US string_sprintf("%s [%s]", host->name, host->address);
+
+return FALSE;
+}
+
+
+
+/*************************************************
+*          Write error message to logs           *
+*************************************************/
+
+/* This writes to the main log and to the message log.
+
+Arguments:
+  host     the current host
+  detail  the current message (addr_item->message)
+  basic_errno the errno (addr_item->basic_errno)
+
+Returns:   nothing
+*/
+
+static void
+write_logs(const host_item *host, const uschar *suffix, int basic_errno)
+{
+gstring * message = LOGGING(outgoing_port)
+  ? string_fmt_append(NULL, "H=%s [%s]:%d", host->name, host->address,
+		    host->port == PORT_NONE ? 25 : host->port)
+  : string_fmt_append(NULL, "H=%s [%s]", host->name, host->address);
+
+if (suffix)
+  {
+  message = string_fmt_append(message, ": %s", suffix);
+  if (basic_errno > 0)
+    message = string_fmt_append(message, ": %s", strerror(basic_errno));
+  }
+else
+  message = string_fmt_append(message, " %s", exim_errstr(basic_errno));
+
+log_write(0, LOG_MAIN, "%s", string_from_gstring(message));
+deliver_msglog("%s %s\n", tod_stamp(tod_log), message->s);
+}
+
+static void
+msglog_line(host_item * host, uschar * message)
+{
+deliver_msglog("%s H=%s [%s] %s\n", tod_stamp(tod_log),
+  host->name, host->address, message);
+}
+
+
+
+#ifndef DISABLE_EVENT
+/*************************************************
+*   Post-defer action                            *
+*************************************************/
+
+/* This expands an arbitrary per-transport string.
+   It might, for example, be used to write to the database log.
+
+Arguments:
+  addr                  the address item containing error information
+  host                  the current host
+  evstr			the event
+
+Returns:   nothing
+*/
+
+static void
+deferred_event_raise(address_item * addr, host_item * host, uschar * evstr)
+{
+uschar * action = addr->transport->event_action;
+const uschar * save_domain;
+uschar * save_local;
+
+if (!action)
+  return;
+
+save_domain = deliver_domain;
+save_local = deliver_localpart;
+
+/*XXX would ip & port already be set up? */
+deliver_host_address = string_copy(host->address);
+deliver_host_port =    host->port == PORT_NONE ? 25 : host->port;
+event_defer_errno =    addr->basic_errno;
+
+router_name =    addr->router->name;
+transport_name = addr->transport->name;
+deliver_domain = addr->domain;
+deliver_localpart = addr->local_part;
+
+(void) event_raise(action, evstr,
+    addr->message
+      ? addr->basic_errno > 0
+	? string_sprintf("%s: %s", addr->message, strerror(addr->basic_errno))
+	: string_copy(addr->message)
+      : addr->basic_errno > 0
+	? string_copy(US strerror(addr->basic_errno))
+	: NULL);
+
+deliver_localpart = save_local;
+deliver_domain =    save_domain;
+router_name = transport_name = NULL;
+}
+#endif
+
+/*************************************************
+*           Reap SMTP specific responses         *
+*************************************************/
+static int
+smtp_discard_responses(smtp_context * sx, smtp_transport_options_block * ob,
+  int count)
+{
+uschar flushbuffer[4096];
+
+while (count-- > 0)
+  {
+  if (!smtp_read_response(sx, flushbuffer, sizeof(flushbuffer),
+	     '2', ob->command_timeout)
+      && (errno != 0 || flushbuffer[0] == 0))
+    break;
+  }
+return count;
+}
+
+
+/* Return boolean success */
+
+static BOOL
+smtp_reap_banner(smtp_context * sx)
+{
+BOOL good_response = smtp_read_response(sx, sx->buffer, sizeof(sx->buffer),
+  '2', (SOB sx->conn_args.ob)->command_timeout);
+#ifdef EXPERIMENTAL_DSN_INFO
+sx->smtp_greeting = string_copy(sx->buffer);
+#endif
+return good_response;
+}
+
+static BOOL
+smtp_reap_ehlo(smtp_context * sx)
+{
+if (!smtp_read_response(sx, sx->buffer, sizeof(sx->buffer), '2',
+       (SOB sx->conn_args.ob)->command_timeout))
+  {
+  if (errno != 0 || sx->buffer[0] == 0 || sx->lmtp)
+    {
+#ifdef EXPERIMENTAL_DSN_INFO
+    sx->helo_response = string_copy(sx->buffer);
+#endif
+    return FALSE;
+    }
+  sx->esmtp = FALSE;
+  }
+#ifdef EXPERIMENTAL_DSN_INFO
+sx->helo_response = string_copy(sx->buffer);
+#endif
+#ifndef DISABLE_EVENT
+(void) event_raise(sx->conn_args.tblock->event_action,
+  US"smtp:ehlo", sx->buffer);
+#endif
+return TRUE;
+}
+
+
+
+#ifndef DISABLE_PIPE_CONNECT
+static uschar *
+ehlo_cache_key(const smtp_context * sx)
+{
+host_item * host = sx->conn_args.host;
+return Ustrchr(host->address, ':')
+  ? string_sprintf("[%s]:%d.EHLO", host->address,
+    host->port == PORT_NONE ? sx->port : host->port)
+  : string_sprintf("%s:%d.EHLO", host->address,
+    host->port == PORT_NONE ? sx->port : host->port);
+}
+
+static void
+write_ehlo_cache_entry(const smtp_context * sx)
+{
+open_db dbblock, * dbm_file;
+
+if ((dbm_file = dbfn_open(US"misc", O_RDWR, &dbblock, TRUE, TRUE)))
+  {
+  uschar * ehlo_resp_key = ehlo_cache_key(sx);
+  dbdata_ehlo_resp er = { .data = sx->ehlo_resp };
+
+  HDEBUG(D_transport) debug_printf("writing clr %04x/%04x cry %04x/%04x\n",
+    sx->ehlo_resp.cleartext_features, sx->ehlo_resp.cleartext_auths,
+    sx->ehlo_resp.crypted_features, sx->ehlo_resp.crypted_auths);
+
+  dbfn_write(dbm_file, ehlo_resp_key, &er, (int)sizeof(er));
+  dbfn_close(dbm_file);
+  }
+}
+
+static void
+invalidate_ehlo_cache_entry(smtp_context * sx)
+{
+open_db dbblock, * dbm_file;
+
+if (  sx->early_pipe_active
+   && (dbm_file = dbfn_open(US"misc", O_RDWR, &dbblock, TRUE, TRUE)))
+  {
+  uschar * ehlo_resp_key = ehlo_cache_key(sx);
+  dbfn_delete(dbm_file, ehlo_resp_key);
+  dbfn_close(dbm_file);
+  }
+}
+
+static BOOL
+read_ehlo_cache_entry(smtp_context * sx)
+{
+open_db dbblock;
+open_db * dbm_file;
+
+if (!(dbm_file = dbfn_open(US"misc", O_RDONLY, &dbblock, FALSE, TRUE)))
+  { DEBUG(D_transport) debug_printf("ehlo-cache: no misc DB\n"); }
+else
+  {
+  uschar * ehlo_resp_key = ehlo_cache_key(sx);
+  dbdata_ehlo_resp * er;
+
+  if (!(er = dbfn_read(dbm_file, ehlo_resp_key)))
+    { DEBUG(D_transport) debug_printf("no ehlo-resp record\n"); }
+  else if (time(NULL) - er->time_stamp > retry_data_expire)
+    {
+    DEBUG(D_transport) debug_printf("ehlo-resp record too old\n");
+    dbfn_close(dbm_file);
+    if ((dbm_file = dbfn_open(US"misc", O_RDWR, &dbblock, TRUE, TRUE)))
+      dbfn_delete(dbm_file, ehlo_resp_key);
+    }
+  else
+    {
+    sx->ehlo_resp = er->data;
+    dbfn_close(dbm_file);
+    DEBUG(D_transport) debug_printf(
+	"EHLO response bits from cache: cleartext 0x%04x/0x%04x crypted 0x%04x/0x%04x\n",
+	er->data.cleartext_features, er->data.cleartext_auths,
+	er->data.crypted_features, er->data.crypted_auths);
+    return TRUE;
+    }
+  dbfn_close(dbm_file);
+  }
+return FALSE;
+}
+
+
+
+/* Return an auths bitmap for the set of AUTH methods offered by the server
+which match our authenticators. */
+
+static unsigned short
+study_ehlo_auths(smtp_context * sx)
+{
+uschar * names;
+auth_instance * au;
+uschar authnum;
+unsigned short authbits = 0;
+
+if (!sx->esmtp) return 0;
+if (!regex_AUTH) regex_AUTH = regex_must_compile(AUTHS_REGEX, FALSE, TRUE);
+if (!regex_match_and_setup(regex_AUTH, sx->buffer, 0, -1)) return 0;
+expand_nmax = -1;						/* reset */
+names = string_copyn(expand_nstring[1], expand_nlength[1]);
+
+for (au = auths, authnum = 0; au; au = au->next, authnum++) if (au->client)
+  {
+  const uschar * list = names;
+  uschar * s;
+  for (int sep = ' '; s = string_nextinlist(&list, &sep, NULL, 0); )
+    if (strcmpic(au->public_name, s) == 0)
+      { authbits |= BIT(authnum); break; }
+  }
+
+DEBUG(D_transport)
+  debug_printf("server offers %s AUTH, methods '%s', bitmap 0x%04x\n",
+    tls_out.active.sock >= 0 ? "crypted" : "plaintext", names, authbits);
+
+if (tls_out.active.sock >= 0)
+  sx->ehlo_resp.crypted_auths = authbits;
+else
+  sx->ehlo_resp.cleartext_auths = authbits;
+return authbits;
+}
+
+
+
+
+/* Wait for and check responses for early-pipelining.
+
+Called from the lower-level smtp_read_response() function
+used for general code that assume synchronisation, if context
+flags indicate outstanding early-pipelining commands.  Also
+called fom sync_responses() which handles pipelined commands.
+
+Arguments:
+ sx	smtp connection context
+ countp	number of outstanding responses, adjusted on return
+
+Return:
+ OK	all well
+ DEFER	error on first read of TLS'd conn
+ FAIL	SMTP error in response
+*/
+int
+smtp_reap_early_pipe(smtp_context * sx, int * countp)
+{
+BOOL pending_BANNER = sx->pending_BANNER;
+BOOL pending_EHLO = sx->pending_EHLO;
+int rc = FAIL;
+
+sx->pending_BANNER = FALSE;	/* clear early to avoid recursion */
+sx->pending_EHLO = FALSE;
+
+if (pending_BANNER)
+  {
+  DEBUG(D_transport) debug_printf("%s expect banner\n", __FUNCTION__);
+  (*countp)--;
+  if (!smtp_reap_banner(sx))
+    {
+    DEBUG(D_transport) debug_printf("bad banner\n");
+    if (tls_out.active.sock >= 0) rc = DEFER;
+    goto fail;
+    }
+  }
+
+if (pending_EHLO)
+  {
+  unsigned peer_offered;
+  unsigned short authbits = 0, * ap;
+
+  DEBUG(D_transport) debug_printf("%s expect ehlo\n", __FUNCTION__);
+  (*countp)--;
+  if (!smtp_reap_ehlo(sx))
+    {
+    DEBUG(D_transport) debug_printf("bad response for EHLO\n");
+    if (tls_out.active.sock >= 0) rc = DEFER;
+    goto fail;
+    }
+
+  /* Compare the actual EHLO response to the cached value we assumed;
+  on difference, dump or rewrite the cache and arrange for a retry. */
+
+  ap = tls_out.active.sock < 0
+      ? &sx->ehlo_resp.cleartext_auths : &sx->ehlo_resp.crypted_auths;
+
+  peer_offered = ehlo_response(sx->buffer,
+	  (tls_out.active.sock < 0 ?  OPTION_TLS : 0)
+	| OPTION_CHUNKING | OPTION_PRDR | OPTION_DSN | OPTION_PIPE | OPTION_SIZE
+	| OPTION_UTF8 | OPTION_EARLY_PIPE
+	);
+  if (  peer_offered != sx->peer_offered
+     || (authbits = study_ehlo_auths(sx)) != *ap)
+    {
+    HDEBUG(D_transport)
+      debug_printf("EHLO %s extensions changed, 0x%04x/0x%04x -> 0x%04x/0x%04x\n",
+		    tls_out.active.sock < 0 ? "cleartext" : "crypted",
+		    sx->peer_offered, *ap, peer_offered, authbits);
+    *(tls_out.active.sock < 0
+      ? &sx->ehlo_resp.cleartext_features : &sx->ehlo_resp.crypted_features) = peer_offered;
+    *ap = authbits;
+    if (peer_offered & OPTION_EARLY_PIPE)
+      write_ehlo_cache_entry(sx);
+    else
+      invalidate_ehlo_cache_entry(sx);
+
+    return OK;		/* just carry on */
+    }
+  }
+return OK;
+
+fail:
+  invalidate_ehlo_cache_entry(sx);
+  (void) smtp_discard_responses(sx, sx->conn_args.ob, *countp);
+  return rc;
+}
+#endif	/*!DISABLE_PIPE_CONNECT*/
+
+
+/*************************************************
+*           Synchronize SMTP responses           *
+*************************************************/
+
+/* This function is called from smtp_deliver() to receive SMTP responses from
+the server, and match them up with the commands to which they relate. When
+PIPELINING is not in use, this function is called after every command, and is
+therefore somewhat over-engineered, but it is simpler to use a single scheme
+that works both with and without PIPELINING instead of having two separate sets
+of code.
+
+The set of commands that are buffered up with pipelining may start with MAIL
+and may end with DATA; in between are RCPT commands that correspond to the
+addresses whose status is PENDING_DEFER. All other commands (STARTTLS, AUTH,
+etc.) are never buffered.
+
+Errors after MAIL or DATA abort the whole process leaving the response in the
+buffer. After MAIL, pending responses are flushed, and the original command is
+re-instated in big_buffer for error messages. For RCPT commands, the remote is
+permitted to reject some recipient addresses while accepting others. However
+certain errors clearly abort the whole process. Set the value in
+transport_return to PENDING_OK if the address is accepted. If there is a
+subsequent general error, it will get reset accordingly. If not, it will get
+converted to OK at the end.
+
+Arguments:
+  sx		    smtp connection context
+  count             the number of responses to read
+  pending_DATA      0 if last command sent was not DATA
+                   +1 if previously had a good recipient
+                   -1 if not previously had a good recipient
+
+Returns:      3 if at least one address had 2xx and one had 5xx
+              2 if at least one address had 5xx but none had 2xx
+              1 if at least one host had a 2xx response, but none had 5xx
+              0 no address had 2xx or 5xx but no errors (all 4xx, or just DATA)
+             -1 timeout while reading RCPT response
+             -2 I/O or other non-response error for RCPT
+             -3 DATA or MAIL failed - errno and buffer set
+	     -4 banner or EHLO failed (early-pipelining)
+	     -5 banner or EHLO failed (early-pipelining, TLS)
+*/
+
+static int
+sync_responses(smtp_context * sx, int count, int pending_DATA)
+{
+address_item * addr = sx->sync_addr;
+smtp_transport_options_block * ob = sx->conn_args.ob;
+int yield = 0;
+
+#ifndef DISABLE_PIPE_CONNECT
+int rc;
+if ((rc = smtp_reap_early_pipe(sx, &count)) != OK)
+  return rc == FAIL ? -4 : -5;
+#endif
+
+/* Handle the response for a MAIL command. On error, reinstate the original
+command in big_buffer for error message use, and flush any further pending
+responses before returning, except after I/O errors and timeouts. */
+
+if (sx->pending_MAIL)
+  {
+  DEBUG(D_transport) debug_printf("%s expect mail\n", __FUNCTION__);
+  count--;
+  sx->pending_MAIL = sx->RCPT_452 = FALSE;
+  if (!smtp_read_response(sx, sx->buffer, sizeof(sx->buffer),
+			  '2', ob->command_timeout))
+    {
+    DEBUG(D_transport) debug_printf("bad response for MAIL\n");
+    Ustrcpy(big_buffer, mail_command);  /* Fits, because it came from there! */
+    if (errno == ERRNO_TLSFAILURE)
+      return -5;
+    if (errno == 0 && sx->buffer[0] != 0)
+      {
+      int save_errno = 0;
+      if (sx->buffer[0] == '4')
+        {
+        save_errno = ERRNO_MAIL4XX;
+        addr->more_errno |= ((sx->buffer[1] - '0')*10 + sx->buffer[2] - '0') << 8;
+        }
+      count = smtp_discard_responses(sx, ob, count);
+      errno = save_errno;
+      }
+
+    if (pending_DATA) count--;  /* Number of RCPT responses to come */
+    while (count-- > 0)		/* Mark any pending addrs with the host used */
+      {
+      while (addr->transport_return != PENDING_DEFER) addr = addr->next;
+      addr->host_used = sx->conn_args.host;
+      addr = addr->next;
+      }
+    return -3;
+    }
+  }
+
+if (pending_DATA) count--;  /* Number of RCPT responses to come */
+
+/* Read and handle the required number of RCPT responses, matching each one up
+with an address by scanning for the next address whose status is PENDING_DEFER.
+*/
+
+while (count-- > 0)
+  {
+  while (addr->transport_return != PENDING_DEFER)
+    if (!(addr = addr->next))
+      return -2;
+
+  /* The address was accepted */
+  addr->host_used = sx->conn_args.host;
+
+  DEBUG(D_transport) debug_printf("%s expect rcpt\n", __FUNCTION__);
+  if (smtp_read_response(sx, sx->buffer, sizeof(sx->buffer),
+			  '2', ob->command_timeout))
+    {
+    yield |= 1;
+    addr->transport_return = PENDING_OK;
+
+    /* If af_dr_retry_exists is set, there was a routing delay on this address;
+    ensure that any address-specific retry record is expunged. We do this both
+    for the basic key and for the version that also includes the sender. */
+
+    if (testflag(addr, af_dr_retry_exists))
+      {
+      uschar *altkey = string_sprintf("%s:<%s>", addr->address_retry_key,
+        sender_address);
+      retry_add_item(addr, altkey, rf_delete);
+      retry_add_item(addr, addr->address_retry_key, rf_delete);
+      }
+    }
+
+  /* Error on first TLS read */
+
+  else if (errno == ERRNO_TLSFAILURE)
+    return -5;
+
+  /* Timeout while reading the response */
+
+  else if (errno == ETIMEDOUT)
+    {
+    uschar *message = string_sprintf("SMTP timeout after RCPT TO:<%s>",
+		transport_rcpt_address(addr, sx->conn_args.tblock->rcpt_include_affixes));
+    set_errno_nohost(sx->first_addr, ETIMEDOUT, message, DEFER, FALSE, &sx->delivery_start);
+    retry_add_item(addr, addr->address_retry_key, 0);
+    update_waiting = FALSE;
+    return -1;
+    }
+
+  /* Handle other errors in obtaining an SMTP response by returning -1. This
+  will cause all the addresses to be deferred. Restore the SMTP command in
+  big_buffer for which we are checking the response, so the error message
+  makes sense. */
+
+  else if (errno != 0 || sx->buffer[0] == 0)
+    {
+    gstring gs = { .size = big_buffer_size, .ptr = 0, .s = big_buffer }, * g = &gs;
+
+    /* Use taint-unchecked routines for writing into big_buffer, trusting
+    that we'll never expand it. */
+
+    g = string_fmt_append_f(g, SVFMT_TAINT_NOCHK, "RCPT TO:<%s>",
+      transport_rcpt_address(addr, sx->conn_args.tblock->rcpt_include_affixes));
+    string_from_gstring(g);
+    return -2;
+    }
+
+  /* Handle SMTP permanent and temporary response codes. */
+
+  else
+    {
+    addr->message =
+      string_sprintf("SMTP error from remote mail server after RCPT TO:<%s>: "
+	"%s", transport_rcpt_address(addr, sx->conn_args.tblock->rcpt_include_affixes),
+	string_printing(sx->buffer));
+    setflag(addr, af_pass_message);
+    if (!sx->verify)
+      msglog_line(sx->conn_args.host, addr->message);
+
+    /* The response was 5xx */
+
+    if (sx->buffer[0] == '5')
+      {
+      addr->transport_return = FAIL;
+      yield |= 2;
+      }
+
+    /* The response was 4xx */
+
+    else
+      {
+      addr->transport_return = DEFER;
+      addr->basic_errno = ERRNO_RCPT4XX;
+      addr->more_errno |= ((sx->buffer[1] - '0')*10 + sx->buffer[2] - '0') << 8;
+
+      if (!sx->verify)
+	{
+#ifndef DISABLE_EVENT
+	event_defer_errno = addr->more_errno;
+	msg_event_raise(US"msg:rcpt:host:defer", addr);
+#endif
+	/* If a 452 and we've had at least one 2xx or 5xx, set next_addr to the
+	start point for another MAIL command. */
+
+	if (addr->more_errno >> 8 == 52  &&  yield & 3)
+	  {
+	  if (!sx->RCPT_452)		/* initialised at MAIL-ack above */
+	    {
+	    DEBUG(D_transport)
+	      debug_printf("%s: seen first 452 too-many-rcpts\n", __FUNCTION__);
+	    sx->RCPT_452 = TRUE;
+	    sx->next_addr = addr;
+	    }
+	  addr->transport_return = PENDING_DEFER;
+	  addr->basic_errno = 0;
+	  }
+	else
+	  {
+	  /* Log temporary errors if there are more hosts to be tried.
+	  If not, log this last one in the == line. */
+
+	  if (sx->conn_args.host->next)
+	    if (LOGGING(outgoing_port))
+	      log_write(0, LOG_MAIN, "H=%s [%s]:%d %s", sx->conn_args.host->name,
+		sx->conn_args.host->address,
+		sx->port == PORT_NONE ? 25 : sx->port, addr->message);
+	    else
+	      log_write(0, LOG_MAIN, "H=%s [%s]: %s", sx->conn_args.host->name,
+		sx->conn_args.host->address, addr->message);
+
+#ifndef DISABLE_EVENT
+	  else
+	    msg_event_raise(US"msg:rcpt:defer", addr);
+#endif
+
+	  /* Do not put this message on the list of those waiting for specific
+	  hosts, as otherwise it is likely to be tried too often. */
+
+	  update_waiting = FALSE;
+
+	  /* Add a retry item for the address so that it doesn't get tried again
+	  too soon. If address_retry_include_sender is true, add the sender address
+	  to the retry key. */
+
+	  retry_add_item(addr,
+	    ob->address_retry_include_sender
+	      ? string_sprintf("%s:<%s>", addr->address_retry_key, sender_address)
+	      : addr->address_retry_key,
+	    0);
+	  }
+	}
+      }
+    }
+  if (count && !(addr = addr->next))
+    return -2;
+  }       /* Loop for next RCPT response */
+
+/* Update where to start at for the next block of responses, unless we
+have already handled all the addresses. */
+
+if (addr) sx->sync_addr = addr->next;
+
+/* Handle a response to DATA. If we have not had any good recipients, either
+previously or in this block, the response is ignored. */
+
+if (pending_DATA != 0)
+  {
+  DEBUG(D_transport) debug_printf("%s expect data\n", __FUNCTION__);
+  if (!smtp_read_response(sx, sx->buffer, sizeof(sx->buffer),
+			'3', ob->command_timeout))
+    {
+    int code;
+    uschar *msg;
+    BOOL pass_message;
+
+    if (errno == ERRNO_TLSFAILURE)	/* Error on first TLS read */
+      return -5;
+
+    if (pending_DATA > 0 || (yield & 1) != 0)
+      {
+      if (errno == 0 && sx->buffer[0] == '4')
+	{
+	errno = ERRNO_DATA4XX;
+	sx->first_addr->more_errno |= ((sx->buffer[1] - '0')*10 + sx->buffer[2] - '0') << 8;
+	}
+      return -3;
+      }
+    (void)check_response(sx->conn_args.host, &errno, 0, sx->buffer, &code, &msg, &pass_message);
+    DEBUG(D_transport) debug_printf("%s\nerror for DATA ignored: pipelining "
+      "is in use and there were no good recipients\n", msg);
+    }
+  }
+
+/* All responses read and handled; MAIL (if present) received 2xx and DATA (if
+present) received 3xx. If any RCPTs were handled and yielded anything other
+than 4xx, yield will be set non-zero. */
+
+return yield;
+}
+
+
+
+
+
+/* Try an authenticator's client entry */
+
+static int
+try_authenticator(smtp_context * sx, auth_instance * au)
+{
+smtp_transport_options_block * ob = sx->conn_args.ob;	/* transport options */
+host_item * host = sx->conn_args.host;			/* host to deliver to */
+int rc;
+
+sx->outblock.authenticating = TRUE;
+rc = (au->info->clientcode)(au, sx, ob->command_timeout,
+			    sx->buffer, sizeof(sx->buffer));
+sx->outblock.authenticating = FALSE;
+DEBUG(D_transport) debug_printf("%s authenticator yielded %d\n", au->name, rc);
+
+/* A temporary authentication failure must hold up delivery to
+this host. After a permanent authentication failure, we carry on
+to try other authentication methods. If all fail hard, try to
+deliver the message unauthenticated unless require_auth was set. */
+
+switch(rc)
+  {
+  case OK:
+    f.smtp_authenticated = TRUE;   /* stops the outer loop */
+    client_authenticator = au->name;
+    if (au->set_client_id)
+      client_authenticated_id = expand_string(au->set_client_id);
+    break;
+
+  /* Failure after writing a command */
+
+  case FAIL_SEND:
+    return FAIL_SEND;
+
+  /* Failure after reading a response */
+
+  case FAIL:
+    if (errno != 0 || sx->buffer[0] != '5') return FAIL;
+    log_write(0, LOG_MAIN, "%s authenticator failed H=%s [%s] %s",
+      au->name, host->name, host->address, sx->buffer);
+    break;
+
+  /* Failure by some other means. In effect, the authenticator
+  decided it wasn't prepared to handle this case. Typically this
+  is the result of "fail" in an expansion string. Do we need to
+  log anything here? Feb 2006: a message is now put in the buffer
+  if logging is required. */
+
+  case CANCELLED:
+    if (*sx->buffer != 0)
+      log_write(0, LOG_MAIN, "%s authenticator cancelled "
+	"authentication H=%s [%s] %s", au->name, host->name,
+	host->address, sx->buffer);
+    break;
+
+  /* Internal problem, message in buffer. */
+
+  case ERROR:
+    set_errno_nohost(sx->addrlist, ERRNO_AUTHPROB, string_copy(sx->buffer),
+	      DEFER, FALSE, &sx->delivery_start);
+    return ERROR;
+  }
+return OK;
+}
+
+
+
+
+/* Do the client side of smtp-level authentication.
+
+Arguments:
+  sx		smtp connection context
+
+sx->buffer should have the EHLO response from server (gets overwritten)
+
+Returns:
+  OK			Success, or failed (but not required): global "smtp_authenticated" set
+  DEFER			Failed authentication (and was required)
+  ERROR			Internal problem
+
+  FAIL_SEND		Failed communications - transmit
+  FAIL			- response
+*/
+
+static int
+smtp_auth(smtp_context * sx)
+{
+host_item * host = sx->conn_args.host;			/* host to deliver to */
+smtp_transport_options_block * ob = sx->conn_args.ob;	/* transport options */
+int require_auth = verify_check_given_host(CUSS &ob->hosts_require_auth, host);
+#ifndef DISABLE_PIPE_CONNECT
+unsigned short authbits = tls_out.active.sock >= 0
+      ? sx->ehlo_resp.crypted_auths : sx->ehlo_resp.cleartext_auths;
+#endif
+uschar * fail_reason = US"server did not advertise AUTH support";
+
+f.smtp_authenticated = FALSE;
+client_authenticator = client_authenticated_id = client_authenticated_sender = NULL;
+
+if (!regex_AUTH)
+  regex_AUTH = regex_must_compile(AUTHS_REGEX, FALSE, TRUE);
+
+/* Is the server offering AUTH? */
+
+if (  sx->esmtp
+   &&
+#ifndef DISABLE_PIPE_CONNECT
+      sx->early_pipe_active ? authbits
+      :
+#endif
+	regex_match_and_setup(regex_AUTH, sx->buffer, 0, -1)
+   )
+  {
+  uschar * names = NULL;
+  expand_nmax = -1;                          /* reset */
+
+#ifndef DISABLE_PIPE_CONNECT
+  if (!sx->early_pipe_active)
+#endif
+    names = string_copyn(expand_nstring[1], expand_nlength[1]);
+
+  /* Must not do this check until after we have saved the result of the
+  regex match above as the check could be another RE. */
+
+  if (  require_auth == OK
+     || verify_check_given_host(CUSS &ob->hosts_try_auth, host) == OK)
+    {
+    DEBUG(D_transport) debug_printf("scanning authentication mechanisms\n");
+    fail_reason = US"no common mechanisms were found";
+
+#ifndef DISABLE_PIPE_CONNECT
+    if (sx->early_pipe_active)
+      {
+      /* Scan our authenticators (which support use by a client and were offered
+      by the server (checked at cache-write time)), not suppressed by
+      client_condition.  If one is found, attempt to authenticate by calling its
+      client function.  We are limited to supporting up to 16 authenticator
+      public-names by the number of bits in a short. */
+
+      auth_instance * au;
+      uschar bitnum;
+      int rc;
+
+      for (bitnum = 0, au = auths;
+	   !f.smtp_authenticated && au && bitnum < 16;
+	   bitnum++, au = au->next) if (authbits & BIT(bitnum))
+	{
+	if (  au->client_condition
+	   && !expand_check_condition(au->client_condition, au->name,
+                   US"client authenticator"))
+	  {
+	  DEBUG(D_transport) debug_printf("skipping %s authenticator: %s\n",
+	    au->name, "client_condition is false");
+	  continue;
+	  }
+
+	/* Found data for a listed mechanism. Call its client entry. Set
+	a flag in the outblock so that data is overwritten after sending so
+	that reflections don't show it. */
+
+	fail_reason = US"authentication attempt(s) failed";
+
+	if ((rc = try_authenticator(sx, au)) != OK)
+	  return rc;
+	}
+      }
+    else
+#endif
+
+    /* Scan the configured authenticators looking for one which is configured
+    for use as a client, which is not suppressed by client_condition, and
+    whose name matches an authentication mechanism supported by the server.
+    If one is found, attempt to authenticate by calling its client function.
+    */
+
+    for (auth_instance * au = auths; !f.smtp_authenticated && au; au = au->next)
+      {
+      uschar *p = names;
+
+      if (  !au->client
+         || (   au->client_condition
+	    &&  !expand_check_condition(au->client_condition, au->name,
+		   US"client authenticator")))
+	{
+	DEBUG(D_transport) debug_printf("skipping %s authenticator: %s\n",
+	  au->name,
+	  (au->client)? "client_condition is false" :
+			"not configured as a client");
+	continue;
+	}
+
+      /* Loop to scan supported server mechanisms */
+
+      while (*p)
+	{
+	int len = Ustrlen(au->public_name);
+	int rc;
+
+	while (isspace(*p)) p++;
+
+	if (strncmpic(au->public_name, p, len) != 0 ||
+	    (p[len] != 0 && !isspace(p[len])))
+	  {
+	  while (*p != 0 && !isspace(*p)) p++;
+	  continue;
+	  }
+
+	/* Found data for a listed mechanism. Call its client entry. Set
+	a flag in the outblock so that data is overwritten after sending so
+	that reflections don't show it. */
+
+	fail_reason = US"authentication attempt(s) failed";
+
+	if ((rc = try_authenticator(sx, au)) != OK)
+	  return rc;
+
+	break;  /* If not authenticated, try next authenticator */
+	}       /* Loop for scanning supported server mechanisms */
+      }         /* Loop for further authenticators */
+    }
+  }
+
+/* If we haven't authenticated, but are required to, give up. */
+
+if (require_auth == OK && !f.smtp_authenticated)
+  {
+#ifndef DISABLE_PIPE_CONNECT
+  invalidate_ehlo_cache_entry(sx);
+#endif
+  set_errno_nohost(sx->addrlist, ERRNO_AUTHFAIL,
+    string_sprintf("authentication required but %s", fail_reason), DEFER,
+    FALSE, &sx->delivery_start);
+  return DEFER;
+  }
+
+return OK;
+}
+
+
+/* Construct AUTH appendix string for MAIL TO */
+/*
+Arguments
+  sx		context for smtp connection
+  p		point in sx->buffer to build string
+  addrlist      chain of potential addresses to deliver
+
+Globals		f.smtp_authenticated
+		client_authenticated_sender
+Return	True on error, otherwise buffer has (possibly empty) terminated string
+*/
+
+static BOOL
+smtp_mail_auth_str(smtp_context * sx, uschar * p, address_item * addrlist)
+{
+smtp_transport_options_block * ob = sx->conn_args.ob;
+uschar * local_authenticated_sender = authenticated_sender;
+
+#ifdef notdef
+  debug_printf("smtp_mail_auth_str: as<%s> os<%s> SA<%s>\n",
+    authenticated_sender, ob->authenticated_sender, f.smtp_authenticated?"Y":"N");
+#endif
+
+if (ob->authenticated_sender)
+  {
+  uschar * new = expand_string(ob->authenticated_sender);
+  if (!new)
+    {
+    if (!f.expand_string_forcedfail)
+      {
+      uschar *message = string_sprintf("failed to expand "
+        "authenticated_sender: %s", expand_string_message);
+      set_errno_nohost(addrlist, ERRNO_EXPANDFAIL, message, DEFER, FALSE, &sx->delivery_start);
+      return TRUE;
+      }
+    }
+  else if (*new)
+    local_authenticated_sender = new;
+  }
+
+/* Add the authenticated sender address if present */
+
+if (  (f.smtp_authenticated || ob->authenticated_sender_force)
+   && local_authenticated_sender)
+  {
+  string_format_nt(p, sizeof(sx->buffer) - (p-sx->buffer), " AUTH=%s",
+    auth_xtextencode(local_authenticated_sender,
+      Ustrlen(local_authenticated_sender)));
+  client_authenticated_sender = string_copy(local_authenticated_sender);
+  }
+else
+  *p = 0;
+
+return FALSE;
+}
+
+
+
+typedef struct smtp_compare_s
+{
+    uschar *			current_sender_address;
+    struct transport_instance *	tblock;
+} smtp_compare_t;
+
+
+/* Create a unique string that identifies this message, it is based on
+sender_address, helo_data and tls_certificate if enabled.
+*/
+
+static uschar *
+smtp_local_identity(uschar * sender, struct transport_instance * tblock)
+{
+address_item * addr1;
+uschar * if1 = US"";
+uschar * helo1 = US"";
+#ifndef DISABLE_TLS
+uschar * tlsc1 = US"";
+#endif
+uschar * save_sender_address = sender_address;
+uschar * local_identity = NULL;
+smtp_transport_options_block * ob = SOB tblock->options_block;
+
+sender_address = sender;
+
+addr1 = deliver_make_addr (sender, TRUE);
+deliver_set_expansions(addr1);
+
+if (ob->interface)
+  if1 = expand_string(ob->interface);
+
+if (ob->helo_data)
+  helo1 = expand_string(ob->helo_data);
+
+#ifndef DISABLE_TLS
+if (ob->tls_certificate)
+  tlsc1 = expand_string(ob->tls_certificate);
+local_identity = string_sprintf ("%s^%s^%s", if1, helo1, tlsc1);
+#else
+local_identity = string_sprintf ("%s^%s", if1, helo1);
+#endif
+
+deliver_set_expansions(NULL);
+sender_address = save_sender_address;
+
+return local_identity;
+}
+
+
+
+/* This routine is a callback that is called from transport_check_waiting.
+This function will evaluate the incoming message versus the previous
+message.  If the incoming message is using a different local identity then
+we will veto this new message.  */
+
+static BOOL
+smtp_are_same_identities(uschar * message_id, smtp_compare_t * s_compare)
+{
+uschar * message_local_identity,
+       * current_local_identity,
+       * new_sender_address;
+
+current_local_identity =
+  smtp_local_identity(s_compare->current_sender_address, s_compare->tblock);
+
+if (!(new_sender_address = deliver_get_sender_address(message_id)))
+    return FALSE;
+
+message_local_identity =
+  smtp_local_identity(new_sender_address, s_compare->tblock);
+
+return Ustrcmp(current_local_identity, message_local_identity) == 0;
+}
+
+
+
+static unsigned
+ehlo_response(uschar * buf, unsigned checks)
+{
+size_t bsize = Ustrlen(buf);
+
+/* debug_printf("%s: check for 0x%04x\n", __FUNCTION__, checks); */
+
+#ifndef DISABLE_TLS
+if (  checks & OPTION_TLS
+   && pcre_exec(regex_STARTTLS, NULL, CS buf, bsize, 0, PCRE_EOPT, NULL, 0) < 0)
+#endif
+  checks &= ~OPTION_TLS;
+
+if (  checks & OPTION_IGNQ
+   && pcre_exec(regex_IGNOREQUOTA, NULL, CS buf, bsize, 0,
+		PCRE_EOPT, NULL, 0) < 0)
+  checks &= ~OPTION_IGNQ;
+
+if (  checks & OPTION_CHUNKING
+   && pcre_exec(regex_CHUNKING, NULL, CS buf, bsize, 0, PCRE_EOPT, NULL, 0) < 0)
+  checks &= ~OPTION_CHUNKING;
+
+#ifndef DISABLE_PRDR
+if (  checks & OPTION_PRDR
+   && pcre_exec(regex_PRDR, NULL, CS buf, bsize, 0, PCRE_EOPT, NULL, 0) < 0)
+#endif
+  checks &= ~OPTION_PRDR;
+
+#ifdef SUPPORT_I18N
+if (  checks & OPTION_UTF8
+   && pcre_exec(regex_UTF8, NULL, CS buf, bsize, 0, PCRE_EOPT, NULL, 0) < 0)
+#endif
+  checks &= ~OPTION_UTF8;
+
+if (  checks & OPTION_DSN
+   && pcre_exec(regex_DSN, NULL, CS buf, bsize, 0, PCRE_EOPT, NULL, 0) < 0)
+  checks &= ~OPTION_DSN;
+
+if (  checks & OPTION_PIPE
+   && pcre_exec(regex_PIPELINING, NULL, CS buf, bsize, 0,
+		PCRE_EOPT, NULL, 0) < 0)
+  checks &= ~OPTION_PIPE;
+
+if (  checks & OPTION_SIZE
+   && pcre_exec(regex_SIZE, NULL, CS buf, bsize, 0, PCRE_EOPT, NULL, 0) < 0)
+  checks &= ~OPTION_SIZE;
+
+#ifndef DISABLE_PIPE_CONNECT
+if (  checks & OPTION_EARLY_PIPE
+   && pcre_exec(regex_EARLY_PIPE, NULL, CS buf, bsize, 0,
+		PCRE_EOPT, NULL, 0) < 0)
+#endif
+  checks &= ~OPTION_EARLY_PIPE;
+
+/* debug_printf("%s: found     0x%04x\n", __FUNCTION__, checks); */
+return checks;
+}
+
+
+
+/* Callback for emitting a BDAT data chunk header.
+
+If given a nonzero size, first flush any buffered SMTP commands
+then emit the command.
+
+Reap previous SMTP command responses if requested, and always reap
+the response from a previous BDAT command.
+
+Args:
+ tctx		transport context
+ chunk_size	value for SMTP BDAT command
+ flags
+   tc_chunk_last	add LAST option to SMTP BDAT command
+   tc_reap_prev		reap response to previous SMTP commands
+
+Returns:
+  OK or ERROR
+  DEFER			TLS error on first read (EHLO-resp); errno set
+*/
+
+static int
+smtp_chunk_cmd_callback(transport_ctx * tctx, unsigned chunk_size,
+  unsigned flags)
+{
+smtp_transport_options_block * ob = SOB tctx->tblock->options_block;
+smtp_context * sx = tctx->smtp_context;
+int cmd_count = 0;
+int prev_cmd_count;
+
+/* Write SMTP chunk header command.  If not reaping responses, note that
+there may be more writes (like, the chunk data) done soon. */
+
+if (chunk_size > 0)
+  {
+#ifndef DISABLE_PIPE_CONNECT
+  BOOL new_conn = !!(sx->outblock.conn_args);
+#endif
+  if((cmd_count = smtp_write_command(sx,
+	      flags & tc_reap_prev ? SCMD_FLUSH : SCMD_MORE,
+	      "BDAT %u%s\r\n", chunk_size, flags & tc_chunk_last ? " LAST" : "")
+     ) < 0) return ERROR;
+  if (flags & tc_chunk_last)
+    data_command = string_copy(big_buffer);  /* Save for later error message */
+#ifndef DISABLE_PIPE_CONNECT
+  /* That command write could have been the one that made the connection.
+  Copy the fd from the client conn ctx (smtp transport specific) to the
+  generic transport ctx. */
+
+  if (new_conn)
+    tctx->u.fd = sx->outblock.cctx->sock;
+#endif
+  }
+
+prev_cmd_count = cmd_count += sx->cmd_count;
+
+/* Reap responses for any previous, but not one we just emitted */
+
+if (chunk_size > 0)
+  prev_cmd_count--;
+if (sx->pending_BDAT)
+  prev_cmd_count--;
+
+if (flags & tc_reap_prev  &&  prev_cmd_count > 0)
+  {
+  DEBUG(D_transport) debug_printf("look for %d responses"
+    " for previous pipelined cmds\n", prev_cmd_count);
+
+  switch(sync_responses(sx, prev_cmd_count, 0))
+    {
+    case 1:				/* 2xx (only) => OK */
+    case 3: sx->good_RCPT = TRUE;	/* 2xx & 5xx => OK & progress made */
+    case 2: sx->completed_addr = TRUE;	/* 5xx (only) => progress made */
+    case 0: break;			/* No 2xx or 5xx, but no probs */
+
+    case -5: errno = ERRNO_TLSFAILURE;
+	     return DEFER;
+#ifndef DISABLE_PIPE_CONNECT
+    case -4:				/* non-2xx for pipelined banner or EHLO */
+#endif
+    case -1:				/* Timeout on RCPT */
+    default: return ERROR;		/* I/O error, or any MAIL/DATA error */
+    }
+  cmd_count = 1;
+  if (!sx->pending_BDAT)
+    pipelining_active = FALSE;
+  }
+
+/* Reap response for an outstanding BDAT */
+
+if (sx->pending_BDAT)
+  {
+  DEBUG(D_transport) debug_printf("look for one response for BDAT\n");
+
+  if (!smtp_read_response(sx, sx->buffer, sizeof(sx->buffer), '2',
+       ob->command_timeout))
+    {
+    if (errno == 0 && sx->buffer[0] == '4')
+      {
+      errno = ERRNO_DATA4XX;	/*XXX does this actually get used? */
+      sx->addrlist->more_errno |=
+	((sx->buffer[1] - '0')*10 + sx->buffer[2] - '0') << 8;
+      }
+    return ERROR;
+    }
+  cmd_count--;
+  sx->pending_BDAT = FALSE;
+  pipelining_active = FALSE;
+  }
+else if (chunk_size > 0)
+  sx->pending_BDAT = TRUE;
+
+
+sx->cmd_count = cmd_count;
+return OK;
+}
+
+
+
+
+
+/*************************************************
+*       Make connection for given message        *
+*************************************************/
+
+/*
+Arguments:
+  ctx		  connection context
+  suppress_tls    if TRUE, don't attempt a TLS connection - this is set for
+                    a second attempt after TLS initialization fails
+
+Returns:          OK    - the connection was made and the delivery attempted;
+                          fd is set in the conn context, tls_out set up.
+                  DEFER - the connection could not be made, or something failed
+                          while setting up the SMTP session, or there was a
+                          non-message-specific error, such as a timeout.
+                  ERROR - helo_data or add_headers or authenticated_sender is
+			  specified for this transport, and the string failed
+			  to expand
+*/
+int
+smtp_setup_conn(smtp_context * sx, BOOL suppress_tls)
+{
+smtp_transport_options_block * ob = sx->conn_args.tblock->options_block;
+BOOL pass_message = FALSE;
+uschar * message = NULL;
+int yield = OK;
+#ifndef DISABLE_TLS
+uschar * tls_errstr;
+#endif
+
+sx->conn_args.ob = ob;
+
+sx->lmtp = strcmpic(ob->protocol, US"lmtp") == 0;
+sx->smtps = strcmpic(ob->protocol, US"smtps") == 0;
+/* sx->ok = FALSE; */
+sx->send_rset = TRUE;
+sx->send_quit = TRUE;
+sx->setting_up = TRUE;
+sx->esmtp = TRUE;
+/* sx->esmtp_sent = FALSE; */
+#ifdef SUPPORT_I18N
+/* sx->utf8_needed = FALSE; */
+#endif
+sx->dsn_all_lasthop = TRUE;
+#ifdef SUPPORT_DANE
+/* sx->conn_args.dane = FALSE; */
+sx->dane_required =
+  verify_check_given_host(CUSS &ob->hosts_require_dane, sx->conn_args.host) == OK;
+#endif
+#ifndef DISABLE_PIPE_CONNECT
+/* sx->early_pipe_active = sx->early_pipe_ok = FALSE; */
+/* sx->ehlo_resp.cleartext_features = sx->ehlo_resp.crypted_features = 0; */
+/* sx->pending_BANNER = sx->pending_EHLO = sx->pending_MAIL = FALSE; */
+#endif
+
+if ((sx->max_rcpt = sx->conn_args.tblock->max_addresses) == 0) sx->max_rcpt = 999999;
+/* sx->peer_offered = 0; */
+/* sx->avoid_option = 0; */
+sx->igquotstr = US"";
+if (!sx->helo_data) sx->helo_data = ob->helo_data;
+#ifdef EXPERIMENTAL_DSN_INFO
+/* sx->smtp_greeting = NULL; */
+/* sx->helo_response = NULL; */
+#endif
+
+smtp_command = US"initial connection";
+/* sx->buffer[0] = '\0'; */
+
+/* Set up the buffer for reading SMTP response packets. */
+
+sx->inblock.buffer = sx->inbuffer;
+sx->inblock.buffersize = sizeof(sx->inbuffer);
+sx->inblock.ptr = sx->inbuffer;
+sx->inblock.ptrend = sx->inbuffer;
+
+/* Set up the buffer for holding SMTP commands while pipelining */
+
+sx->outblock.buffer = sx->outbuffer;
+sx->outblock.buffersize = sizeof(sx->outbuffer);
+sx->outblock.ptr = sx->outbuffer;
+/* sx->outblock.cmd_count = 0; */
+/* sx->outblock.authenticating = FALSE; */
+/* sx->outblock.conn_args = NULL; */
+
+/* Reset the parameters of a TLS session. */
+
+tls_out.bits = 0;
+tls_out.cipher = NULL;	/* the one we may use for this transport */
+tls_out.ourcert = NULL;
+tls_out.peercert = NULL;
+tls_out.peerdn = NULL;
+#ifdef USE_OPENSSL
+tls_out.sni = NULL;
+#endif
+tls_out.ocsp = OCSP_NOT_REQ;
+#ifdef EXPERIMENTAL_TLS_RESUME
+tls_out.resumption = 0;
+#endif
+tls_out.ver = NULL;
+
+/* Flip the legacy TLS-related variables over to the outbound set in case
+they're used in the context of the transport.  Don't bother resetting
+afterward (when being used by a transport) as we're in a subprocess.
+For verify, unflipped once the callout is dealt with */
+
+tls_modify_variables(&tls_out);
+
+#ifdef DISABLE_TLS
+if (sx->smtps)
+  {
+  set_errno_nohost(sx->addrlist, ERRNO_TLSFAILURE, US"TLS support not available",
+	    DEFER, FALSE, &sx->delivery_start);
+  return ERROR;
+  }
+#else
+
+/* If we have a proxied TLS connection, check usability for this message */
+
+if (continue_hostname && continue_proxy_cipher)
+  {
+  int rc;
+  const uschar * sni = US"";
+
+# ifdef SUPPORT_DANE
+  /* Check if the message will be DANE-verified; if so force its SNI */
+
+  tls_out.dane_verified = FALSE;
+  smtp_port_for_connect(sx->conn_args.host, sx->port);
+  if (  sx->conn_args.host->dnssec == DS_YES
+     && (  sx->dane_required
+	|| verify_check_given_host(CUSS &ob->hosts_try_dane, sx->conn_args.host) == OK
+     )  )
+    switch (rc = tlsa_lookup(sx->conn_args.host, &sx->conn_args.tlsa_dnsa, sx->dane_required))
+      {
+      case OK:		sx->conn_args.dane = TRUE;
+			ob->tls_tempfail_tryclear = FALSE;	/* force TLS */
+			ob->tls_sni = sx->first_addr->domain;	/* force SNI */
+			break;
+      case FAIL_FORCED:	break;
+      default:		set_errno_nohost(sx->addrlist, ERRNO_DNSDEFER,
+			      string_sprintf("DANE error: tlsa lookup %s",
+				rc_to_string(rc)),
+			      rc, FALSE, &sx->delivery_start);
+#  ifndef DISABLE_EVENT
+			    (void) event_raise(sx->conn_args.tblock->event_action,
+			      US"dane:fail", sx->dane_required
+				?  US"dane-required" : US"dnssec-invalid");
+#  endif
+			    return rc;
+      }
+# endif
+
+  /* If the SNI or the DANE status required for the new message differs from the
+  existing conn drop the connection to force a new one. */
+
+  if (ob->tls_sni && !(sni = expand_cstring(ob->tls_sni)))
+    log_write(0, LOG_MAIN|LOG_PANIC,
+      "<%s>: failed to expand transport's tls_sni value: %s",
+      sx->addrlist->address, expand_string_message);
+
+# ifdef SUPPORT_DANE
+  if (  (continue_proxy_sni ? (Ustrcmp(continue_proxy_sni, sni) == 0) : !*sni)
+     && continue_proxy_dane == sx->conn_args.dane)
+    {
+    tls_out.sni = US sni;
+    if ((tls_out.dane_verified = continue_proxy_dane))
+      sx->conn_args.host->dnssec = DS_YES;
+    }
+# else
+  if ((continue_proxy_sni ? (Ustrcmp(continue_proxy_sni, sni) == 0) : !*sni))
+    tls_out.sni = US sni;
+# endif
+  else
+    {
+    DEBUG(D_transport)
+      debug_printf("Closing proxied-TLS connection due to SNI mismatch\n");
+
+    HDEBUG(D_transport|D_acl|D_v) debug_printf_indent("  SMTP>> QUIT\n");
+    write(0, "QUIT\r\n", 6);
+    close(0);
+    continue_hostname = continue_proxy_cipher = NULL;
+    f.continue_more = FALSE;
+    continue_sequence = 1;	/* Unfortunately, this process cannot affect success log
+    				which is done by delivery proc.  Would have to pass this
+				back through reporting pipe. */
+    }
+  }
+#endif	/*!DISABLE_TLS*/
+
+/* Make a connection to the host if this isn't a continued delivery, and handle
+the initial interaction and HELO/EHLO/LHLO. Connect timeout errors are handled
+specially so they can be identified for retries. */
+
+if (!continue_hostname)
+  {
+  if (sx->verify)
+    HDEBUG(D_verify) debug_printf("interface=%s port=%d\n", sx->conn_args.interface, sx->port);
+
+  /* Get the actual port the connection will use, into sx->conn_args.host */
+
+  smtp_port_for_connect(sx->conn_args.host, sx->port);
+
+#ifdef SUPPORT_DANE
+    /* Do TLSA lookup for DANE */
+    {
+    tls_out.dane_verified = FALSE;
+    tls_out.tlsa_usage = 0;
+
+    if (sx->conn_args.host->dnssec == DS_YES)
+      {
+      int rc;
+      if(  sx->dane_required
+	|| verify_check_given_host(CUSS &ob->hosts_try_dane, sx->conn_args.host) == OK
+	)
+	switch (rc = tlsa_lookup(sx->conn_args.host, &sx->conn_args.tlsa_dnsa, sx->dane_required))
+	  {
+	  case OK:		sx->conn_args.dane = TRUE;
+				ob->tls_tempfail_tryclear = FALSE;	/* force TLS */
+				ob->tls_sni = sx->first_addr->domain;	/* force SNI */
+				break;
+	  case FAIL_FORCED:	break;
+	  default:		set_errno_nohost(sx->addrlist, ERRNO_DNSDEFER,
+				  string_sprintf("DANE error: tlsa lookup %s",
+				    rc_to_string(rc)),
+				  rc, FALSE, &sx->delivery_start);
+# ifndef DISABLE_EVENT
+				(void) event_raise(sx->conn_args.tblock->event_action,
+				  US"dane:fail", sx->dane_required
+				    ?  US"dane-required" : US"dnssec-invalid");
+# endif
+				return rc;
+	  }
+      }
+    else if (sx->dane_required)
+      {
+      set_errno_nohost(sx->addrlist, ERRNO_DNSDEFER,
+	string_sprintf("DANE error: %s lookup not DNSSEC", sx->conn_args.host->name),
+	FAIL, FALSE, &sx->delivery_start);
+# ifndef DISABLE_EVENT
+      (void) event_raise(sx->conn_args.tblock->event_action,
+	US"dane:fail", US"dane-required");
+# endif
+      return FAIL;
+      }
+    }
+#endif	/*DANE*/
+
+  /* Make the TCP connection */
+
+  sx->cctx.tls_ctx = NULL;
+  sx->inblock.cctx = sx->outblock.cctx = &sx->cctx;
+  sx->avoid_option = sx->peer_offered = smtp_peer_options = 0;
+
+#ifndef DISABLE_PIPE_CONNECT
+  if (  verify_check_given_host(CUSS &ob->hosts_pipe_connect,
+					    sx->conn_args.host) == OK)
+
+    /* We don't find out the local ip address until the connect, so if
+    the helo string might use it avoid doing early-pipelining. */
+
+    if (  !sx->helo_data
+       || !Ustrstr(sx->helo_data, "$sending_ip_address")
+       || Ustrstr(sx->helo_data, "def:sending_ip_address")
+       )
+      {
+      sx->early_pipe_ok = TRUE;
+      if (  read_ehlo_cache_entry(sx)
+	 && sx->ehlo_resp.cleartext_features & OPTION_EARLY_PIPE)
+	{
+	DEBUG(D_transport)
+	  debug_printf("Using cached cleartext PIPE_CONNECT\n");
+	sx->early_pipe_active = TRUE;
+	sx->peer_offered = sx->ehlo_resp.cleartext_features;
+	}
+      }
+    else DEBUG(D_transport)
+      debug_printf("helo needs $sending_ip_address\n");
+
+PIPE_CONNECT_RETRY:
+  if (sx->early_pipe_active)
+    sx->outblock.conn_args = &sx->conn_args;
+  else
+#endif
+    {
+    if ((sx->cctx.sock = smtp_connect(&sx->conn_args, NULL)) < 0)
+      {
+      set_errno_nohost(sx->addrlist,
+	errno == ETIMEDOUT ? ERRNO_CONNECTTIMEOUT : errno,
+	sx->verify ? US strerror(errno) : NULL,
+	DEFER, FALSE, &sx->delivery_start);
+      sx->send_quit = FALSE;
+      return DEFER;
+      }
+    }
+  /* Expand the greeting message while waiting for the initial response. (Makes
+  sense if helo_data contains ${lookup dnsdb ...} stuff). The expansion is
+  delayed till here so that $sending_interface and $sending_port are set. */
+/*XXX early-pipe: they still will not be. Is there any way to find out what they
+will be?  Somehow I doubt it. */
+
+  if (sx->helo_data)
+    if (!(sx->helo_data = expand_string(sx->helo_data)))
+      if (sx->verify)
+	log_write(0, LOG_MAIN|LOG_PANIC,
+	  "<%s>: failed to expand transport's helo_data value for callout: %s",
+	  sx->addrlist->address, expand_string_message);
+
+#ifdef SUPPORT_I18N
+  if (sx->helo_data)
+    {
+    expand_string_message = NULL;
+    if ((sx->helo_data = string_domain_utf8_to_alabel(sx->helo_data,
+					      &expand_string_message)),
+	expand_string_message)
+      if (sx->verify)
+	log_write(0, LOG_MAIN|LOG_PANIC,
+	  "<%s>: failed to expand transport's helo_data value for callout: %s",
+	  sx->addrlist->address, expand_string_message);
+      else
+	sx->helo_data = NULL;
+    }
+#endif
+
+  /* The first thing is to wait for an initial OK response. The dreaded "goto"
+  is nevertheless a reasonably clean way of programming this kind of logic,
+  where you want to escape on any error. */
+
+  if (!sx->smtps)
+    {
+#ifndef DISABLE_PIPE_CONNECT
+    if (sx->early_pipe_active)
+      {
+      sx->pending_BANNER = TRUE;	/* sync_responses() must eventually handle */
+      sx->outblock.cmd_count = 1;
+      }
+    else
+#endif
+      {
+#ifdef TCP_QUICKACK
+      (void) setsockopt(sx->cctx.sock, IPPROTO_TCP, TCP_QUICKACK, US &off,
+			sizeof(off));
+#endif
+      if (!smtp_reap_banner(sx))
+	goto RESPONSE_FAILED;
+      }
+
+#ifndef DISABLE_EVENT
+      {
+      uschar * s;
+      lookup_dnssec_authenticated = sx->conn_args.host->dnssec==DS_YES ? US"yes"
+	: sx->conn_args.host->dnssec==DS_NO ? US"no" : NULL;
+      s = event_raise(sx->conn_args.tblock->event_action, US"smtp:connect", sx->buffer);
+      if (s)
+	{
+	set_errno_nohost(sx->addrlist, ERRNO_EXPANDFAIL,
+	  string_sprintf("deferred by smtp:connect event expansion: %s", s),
+	  DEFER, FALSE, &sx->delivery_start);
+	yield = DEFER;
+	goto SEND_QUIT;
+	}
+      }
+#endif
+
+    /* Now check if the helo_data expansion went well, and sign off cleanly if
+    it didn't. */
+
+    if (!sx->helo_data)
+      {
+      message = string_sprintf("failed to expand helo_data: %s",
+        expand_string_message);
+      set_errno_nohost(sx->addrlist, ERRNO_EXPANDFAIL, message, DEFER, FALSE, &sx->delivery_start);
+      yield = DEFER;
+      goto SEND_QUIT;
+      }
+    }
+
+/** Debugging without sending a message
+sx->addrlist->transport_return = DEFER;
+goto SEND_QUIT;
+**/
+
+  /* Errors that occur after this point follow an SMTP command, which is
+  left in big_buffer by smtp_write_command() for use in error messages. */
+
+  smtp_command = big_buffer;
+
+  /* Tell the remote who we are...
+
+  February 1998: A convention has evolved that ESMTP-speaking MTAs include the
+  string "ESMTP" in their greeting lines, so make Exim send EHLO if the
+  greeting is of this form. The assumption was that the far end supports it
+  properly... but experience shows that there are some that give 5xx responses,
+  even though the banner includes "ESMTP" (there's a bloody-minded one that
+  says "ESMTP not spoken here"). Cope with that case.
+
+  September 2000: Time has passed, and it seems reasonable now to always send
+  EHLO at the start. It is also convenient to make the change while installing
+  the TLS stuff.
+
+  July 2003: Joachim Wieland met a broken server that advertises "PIPELINING"
+  but times out after sending MAIL FROM, RCPT TO and DATA all together. There
+  would be no way to send out the mails, so there is now a host list
+  "hosts_avoid_esmtp" that disables ESMTP for special hosts and solves the
+  PIPELINING problem as well. Maybe it can also be useful to cure other
+  problems with broken servers.
+
+  Exim originally sent "Helo" at this point and ran for nearly a year that way.
+  Then somebody tried it with a Microsoft mailer... It seems that all other
+  mailers use upper case for some reason (the RFC is quite clear about case
+  independence) so, for peace of mind, I gave in. */
+
+  sx->esmtp = verify_check_given_host(CUSS &ob->hosts_avoid_esmtp, sx->conn_args.host) != OK;
+
+  /* Alas; be careful, since this goto is not an error-out, so conceivably
+  we might set data between here and the target which we assume to exist
+  and be usable.  I can see this coming back to bite us. */
+#ifndef DISABLE_TLS
+  if (sx->smtps)
+    {
+    smtp_peer_options |= OPTION_TLS;
+    suppress_tls = FALSE;
+    ob->tls_tempfail_tryclear = FALSE;
+    smtp_command = US"SSL-on-connect";
+    goto TLS_NEGOTIATE;
+    }
+#endif
+
+  if (sx->esmtp)
+    {
+    if (smtp_write_command(sx,
+#ifndef DISABLE_PIPE_CONNECT
+	  sx->early_pipe_active ? SCMD_BUFFER :
+#endif
+	    SCMD_FLUSH,
+	  "%s %s\r\n", sx->lmtp ? "LHLO" : "EHLO", sx->helo_data) < 0)
+      goto SEND_FAILED;
+    sx->esmtp_sent = TRUE;
+
+#ifndef DISABLE_PIPE_CONNECT
+    if (sx->early_pipe_active)
+      {
+      sx->pending_EHLO = TRUE;
+
+      /* If we have too many authenticators to handle and might need to AUTH
+      for this transport, pipeline no further as we will need the
+      list of auth methods offered.  Reap the banner and EHLO. */
+
+      if (  (ob->hosts_require_auth || ob->hosts_try_auth)
+	 && f.smtp_in_early_pipe_no_auth)
+	{
+	DEBUG(D_transport) debug_printf("may need to auth, so pipeline no further\n");
+	if (smtp_write_command(sx, SCMD_FLUSH, NULL) < 0)
+	  goto SEND_FAILED;
+	if (sync_responses(sx, 2, 0) != 0)
+	  {
+	  HDEBUG(D_transport)
+	    debug_printf("failed reaping pipelined cmd responses\n");
+	  goto RESPONSE_FAILED;
+	  }
+	sx->early_pipe_active = FALSE;
+	}
+      }
+    else
+#endif
+      if (!smtp_reap_ehlo(sx))
+	goto RESPONSE_FAILED;
+    }
+  else
+    DEBUG(D_transport)
+      debug_printf("not sending EHLO (host matches hosts_avoid_esmtp)\n");
+
+#ifndef DISABLE_PIPE_CONNECT
+  if (!sx->early_pipe_active)
+#endif
+    if (!sx->esmtp)
+      {
+      BOOL good_response;
+      int n = sizeof(sx->buffer);
+      uschar * rsp = sx->buffer;
+
+      if (sx->esmtp_sent && (n = Ustrlen(sx->buffer) + 1) < sizeof(sx->buffer)/2)
+	{ rsp = sx->buffer + n; n = sizeof(sx->buffer) - n; }
+
+      if (smtp_write_command(sx, SCMD_FLUSH, "HELO %s\r\n", sx->helo_data) < 0)
+	goto SEND_FAILED;
+      good_response = smtp_read_response(sx, rsp, n, '2', ob->command_timeout);
+#ifdef EXPERIMENTAL_DSN_INFO
+      sx->helo_response = string_copy(rsp);
+#endif
+      if (!good_response)
+	{
+	/* Handle special logging for a closed connection after HELO
+	when had previously sent EHLO */
+
+	if (rsp != sx->buffer && rsp[0] == 0 && (errno == 0 || errno == ECONNRESET))
+	  {
+	  errno = ERRNO_SMTPCLOSED;
+	  goto EHLOHELO_FAILED;
+	  }
+	memmove(sx->buffer, rsp, Ustrlen(rsp));
+	goto RESPONSE_FAILED;
+	}
+      }
+
+  if (sx->esmtp || sx->lmtp)
+    {
+#ifndef DISABLE_PIPE_CONNECT
+    if (!sx->early_pipe_active)
+#endif
+      {
+      sx->peer_offered = ehlo_response(sx->buffer,
+	OPTION_TLS	/* others checked later */
+#ifndef DISABLE_PIPE_CONNECT
+	| (sx->early_pipe_ok
+	  ?   OPTION_IGNQ
+	    | OPTION_CHUNKING | OPTION_PRDR | OPTION_DSN | OPTION_PIPE | OPTION_SIZE
+#ifdef SUPPORT_I18N
+	    | OPTION_UTF8
+#endif
+	    | OPTION_EARLY_PIPE
+	  : 0
+	  )
+#endif
+	);
+#ifndef DISABLE_PIPE_CONNECT
+      if (sx->early_pipe_ok)
+	{
+	sx->ehlo_resp.cleartext_features = sx->peer_offered;
+
+	if (  (sx->peer_offered & (OPTION_PIPE | OPTION_EARLY_PIPE))
+	   == (OPTION_PIPE | OPTION_EARLY_PIPE))
+	  {
+	  DEBUG(D_transport) debug_printf("PIPE_CONNECT usable in future for this IP\n");
+	  sx->ehlo_resp.cleartext_auths = study_ehlo_auths(sx);
+	  write_ehlo_cache_entry(sx);
+	  }
+	}
+#endif
+      }
+
+  /* Set tls_offered if the response to EHLO specifies support for STARTTLS. */
+
+#ifndef DISABLE_TLS
+    smtp_peer_options |= sx->peer_offered & OPTION_TLS;
+#endif
+    }
+  }
+
+/* For continuing deliveries down the same channel, having re-exec'd  the socket
+is the standard input; for a socket held open from verify it is recorded
+in the cutthrough context block.  Either way we don't need to redo EHLO here
+(but may need to do so for TLS - see below).
+Set up the pointer to where subsequent commands will be left, for
+error messages. Note that smtp_peer_options will have been
+set from the command line if they were set in the process that passed the
+connection on. */
+
+/*XXX continue case needs to propagate DSN_INFO, prob. in deliver.c
+as the continue goes via transport_pass_socket() and doublefork and exec.
+It does not wait.  Unclear how we keep separate host's responses
+separate - we could match up by host ip+port as a bodge. */
+
+else
+  {
+  if (cutthrough.cctx.sock >= 0 && cutthrough.callout_hold_only)
+    {
+    sx->cctx = cutthrough.cctx;
+    sx->conn_args.host->port = sx->port = cutthrough.host.port;
+    }
+  else
+    {
+    sx->cctx.sock = 0;				/* stdin */
+    sx->cctx.tls_ctx = NULL;
+    smtp_port_for_connect(sx->conn_args.host, sx->port);	/* Record the port that was used */
+    }
+  sx->inblock.cctx = sx->outblock.cctx = &sx->cctx;
+  smtp_command = big_buffer;
+  sx->peer_offered = smtp_peer_options;
+  sx->helo_data = NULL;		/* ensure we re-expand ob->helo_data */
+
+  /* For a continued connection with TLS being proxied for us, or a
+  held-open verify connection with TLS, nothing more to do. */
+
+  if (  continue_proxy_cipher
+     || (cutthrough.cctx.sock >= 0 && cutthrough.callout_hold_only
+         && cutthrough.is_tls)
+     )
+    {
+    sx->pipelining_used = pipelining_active = !!(smtp_peer_options & OPTION_PIPE);
+    HDEBUG(D_transport) debug_printf("continued connection, %s TLS\n",
+      continue_proxy_cipher ? "proxied" : "verify conn with");
+    return OK;
+    }
+  HDEBUG(D_transport) debug_printf("continued connection, no TLS\n");
+  }
+
+/* If TLS is available on this connection, whether continued or not, attempt to
+start up a TLS session, unless the host is in hosts_avoid_tls. If successful,
+send another EHLO - the server may give a different answer in secure mode. We
+use a separate buffer for reading the response to STARTTLS so that if it is
+negative, the original EHLO data is available for subsequent analysis, should
+the client not be required to use TLS. If the response is bad, copy the buffer
+for error analysis. */
+
+#ifndef DISABLE_TLS
+if (  smtp_peer_options & OPTION_TLS
+   && !suppress_tls
+   && verify_check_given_host(CUSS &ob->hosts_avoid_tls, sx->conn_args.host) != OK
+   && (  !sx->verify
+      || verify_check_given_host(CUSS &ob->hosts_verify_avoid_tls, sx->conn_args.host) != OK
+   )  )
+  {
+  uschar buffer2[4096];
+
+  if (smtp_write_command(sx, SCMD_FLUSH, "STARTTLS\r\n") < 0)
+    goto SEND_FAILED;
+
+#ifndef DISABLE_PIPE_CONNECT
+  /* If doing early-pipelining reap the banner and EHLO-response but leave
+  the response for the STARTTLS we just sent alone. */
+
+  if (sx->early_pipe_active && sync_responses(sx, 2, 0) != 0)
+    {
+    HDEBUG(D_transport)
+      debug_printf("failed reaping pipelined cmd responses\n");
+    close(sx->cctx.sock);
+    sx->cctx.sock = -1;
+    sx->early_pipe_active = FALSE;
+    goto PIPE_CONNECT_RETRY;
+    }
+#endif
+
+  /* If there is an I/O error, transmission of this message is deferred. If
+  there is a temporary rejection of STARRTLS and tls_tempfail_tryclear is
+  false, we also defer. However, if there is a temporary rejection of STARTTLS
+  and tls_tempfail_tryclear is true, or if there is an outright rejection of
+  STARTTLS, we carry on. This means we will try to send the message in clear,
+  unless the host is in hosts_require_tls (tested below). */
+
+  if (!smtp_read_response(sx, buffer2, sizeof(buffer2), '2', ob->command_timeout))
+    {
+    if (  errno != 0
+       || buffer2[0] == 0
+       || (buffer2[0] == '4' && !ob->tls_tempfail_tryclear)
+       )
+      {
+      Ustrncpy(sx->buffer, buffer2, sizeof(sx->buffer));
+      sx->buffer[sizeof(sx->buffer)-1] = '\0';
+      goto RESPONSE_FAILED;
+      }
+    }
+
+  /* STARTTLS accepted: try to negotiate a TLS session. */
+
+  else
+  TLS_NEGOTIATE:
+    {
+    if (!tls_client_start(&sx->cctx, &sx->conn_args, sx->addrlist, &tls_out, &tls_errstr))
+      {
+      /* TLS negotiation failed; give an error. From outside, this function may
+      be called again to try in clear on a new connection, if the options permit
+      it for this host. */
+#ifdef USE_GNUTLS
+  GNUTLS_CONN_FAILED:
+#endif
+      DEBUG(D_tls) debug_printf("TLS session fail: %s\n", tls_errstr);
+
+# ifdef SUPPORT_DANE
+      if (sx->conn_args.dane)
+        {
+	log_write(0, LOG_MAIN,
+	  "DANE attempt failed; TLS connection to %s [%s]: %s",
+	  sx->conn_args.host->name, sx->conn_args.host->address, tls_errstr);
+#  ifndef DISABLE_EVENT
+	(void) event_raise(sx->conn_args.tblock->event_action,
+	  US"dane:fail", US"validation-failure");	/* could do with better detail */
+#  endif
+	}
+# endif
+
+      errno = ERRNO_TLSFAILURE;
+      message = string_sprintf("TLS session: %s", tls_errstr);
+      sx->send_quit = FALSE;
+      goto TLS_FAILED;
+      }
+
+    /* TLS session is set up */
+
+    smtp_peer_options_wrap = smtp_peer_options;
+    for (address_item * addr = sx->addrlist; addr; addr = addr->next)
+      if (addr->transport_return == PENDING_DEFER)
+        {
+        addr->cipher = tls_out.cipher;
+        addr->ourcert = tls_out.ourcert;
+        addr->peercert = tls_out.peercert;
+        addr->peerdn = tls_out.peerdn;
+	addr->ocsp = tls_out.ocsp;
+        addr->tlsver = tls_out.ver;
+        }
+    }
+  }
+
+/* if smtps, we'll have smtp_command set to something else; always safe to
+reset it here. */
+smtp_command = big_buffer;
+
+/* If we started TLS, redo the EHLO/LHLO exchange over the secure channel. If
+helo_data is null, we are dealing with a connection that was passed from
+another process, and so we won't have expanded helo_data above. We have to
+expand it here. $sending_ip_address and $sending_port are set up right at the
+start of the Exim process (in exim.c). */
+
+if (tls_out.active.sock >= 0)
+  {
+  uschar * greeting_cmd;
+
+  if (!sx->helo_data && !(sx->helo_data = expand_string(ob->helo_data)))
+    {
+    uschar *message = string_sprintf("failed to expand helo_data: %s",
+      expand_string_message);
+    set_errno_nohost(sx->addrlist, ERRNO_EXPANDFAIL, message, DEFER, FALSE, &sx->delivery_start);
+    yield = DEFER;
+    goto SEND_QUIT;
+    }
+
+#ifndef DISABLE_PIPE_CONNECT
+  /* For SMTPS there is no cleartext early-pipe; use the crypted permission bit.
+  We're unlikely to get the group sent and delivered before the server sends its
+  banner, but it's still worth sending as a group.
+  For STARTTLS allow for cleartext early-pipe but no crypted early-pipe, but not
+  the reverse.  */
+
+  if (sx->smtps ? sx->early_pipe_ok : sx->early_pipe_active)
+    {
+    sx->peer_offered = sx->ehlo_resp.crypted_features;
+    if ((sx->early_pipe_active =
+	 !!(sx->ehlo_resp.crypted_features & OPTION_EARLY_PIPE)))
+      DEBUG(D_transport) debug_printf("Using cached crypted PIPE_CONNECT\n");
+    }
+#endif
+
+  /* For SMTPS we need to wait for the initial OK response. */
+  if (sx->smtps)
+#ifndef DISABLE_PIPE_CONNECT
+    if (sx->early_pipe_active)
+      {
+      sx->pending_BANNER = TRUE;
+      sx->outblock.cmd_count = 1;
+      }
+    else
+#endif
+      if (!smtp_reap_banner(sx))
+	goto RESPONSE_FAILED;
+
+  if (sx->lmtp)
+    greeting_cmd = US"LHLO";
+  else if (sx->esmtp)
+    greeting_cmd = US"EHLO";
+  else
+    {
+    greeting_cmd = US"HELO";
+    DEBUG(D_transport)
+      debug_printf("not sending EHLO (host matches hosts_avoid_esmtp)\n");
+    }
+
+  if (smtp_write_command(sx,
+#ifndef DISABLE_PIPE_CONNECT
+	sx->early_pipe_active ? SCMD_BUFFER :
+#endif
+	  SCMD_FLUSH,
+	"%s %s\r\n", greeting_cmd, sx->helo_data) < 0)
+    goto SEND_FAILED;
+
+#ifndef DISABLE_PIPE_CONNECT
+  if (sx->early_pipe_active)
+    sx->pending_EHLO = TRUE;
+  else
+#endif
+    {
+    if (!smtp_reap_ehlo(sx))
+#ifdef USE_GNUTLS
+      {
+      /* The GnuTLS layer in Exim only spots a server-rejection of a client
+      cert late, under TLS1.3 - which means here; the first time we try to
+      receive crypted data.  Treat it as if it was a connect-time failure.
+      See also the early-pipe equivalent... which will be hard; every call
+      to sync_responses will need to check the result.
+      It would be nicer to have GnuTLS check the cert during the handshake.
+      Can it do that, with all the flexibility we need? */
+
+      tls_errstr = US"error on first read";
+      goto GNUTLS_CONN_FAILED;
+      }
+#else
+      goto RESPONSE_FAILED;
+#endif
+    smtp_peer_options = 0;
+    }
+  }
+
+/* If the host is required to use a secure channel, ensure that we
+have one. */
+
+else if (  sx->smtps
+# ifdef SUPPORT_DANE
+	|| sx->conn_args.dane
+# endif
+	|| verify_check_given_host(CUSS &ob->hosts_require_tls, sx->conn_args.host) == OK
+	)
+  {
+  errno = ERRNO_TLSREQUIRED;
+  message = string_sprintf("a TLS session is required, but %s",
+    smtp_peer_options & OPTION_TLS
+    ? "an attempt to start TLS failed" : "the server did not offer TLS support");
+# if defined(SUPPORT_DANE) && !defined(DISABLE_EVENT)
+  if (sx->conn_args.dane)
+    (void) event_raise(sx->conn_args.tblock->event_action, US"dane:fail",
+      smtp_peer_options & OPTION_TLS
+      ? US"validation-failure"		/* could do with better detail */
+      : US"starttls-not-supported");
+# endif
+  goto TLS_FAILED;
+  }
+#endif	/*DISABLE_TLS*/
+
+/* If TLS is active, we have just started it up and re-done the EHLO command,
+so its response needs to be analyzed. If TLS is not active and this is a
+continued session down a previously-used socket, we haven't just done EHLO, so
+we skip this. */
+
+if (continue_hostname == NULL
+#ifndef DISABLE_TLS
+    || tls_out.active.sock >= 0
+#endif
+    )
+  {
+  if (sx->esmtp || sx->lmtp)
+    {
+#ifndef DISABLE_PIPE_CONNECT
+  if (!sx->early_pipe_active)
+#endif
+    {
+    sx->peer_offered = ehlo_response(sx->buffer,
+	0 /* no TLS */
+#ifndef DISABLE_PIPE_CONNECT
+	| (sx->lmtp && ob->lmtp_ignore_quota ? OPTION_IGNQ : 0)
+	| OPTION_DSN | OPTION_PIPE | OPTION_SIZE
+	| OPTION_CHUNKING | OPTION_PRDR | OPTION_UTF8
+	| (tls_out.active.sock >= 0 ? OPTION_EARLY_PIPE : 0) /* not for lmtp */
+
+#else
+
+	| (sx->lmtp && ob->lmtp_ignore_quota ? OPTION_IGNQ : 0)
+	| OPTION_CHUNKING
+	| OPTION_PRDR
+# ifdef SUPPORT_I18N
+	| (sx->addrlist->prop.utf8_msg ? OPTION_UTF8 : 0)
+	  /*XXX if we hand peercaps on to continued-conn processes,
+		must not depend on this addr */
+# endif
+	| OPTION_DSN
+	| OPTION_PIPE
+	| (ob->size_addition >= 0 ? OPTION_SIZE : 0)
+#endif
+      );
+#ifndef DISABLE_PIPE_CONNECT
+    if (tls_out.active.sock >= 0)
+      sx->ehlo_resp.crypted_features = sx->peer_offered;
+#endif
+    }
+
+    /* Set for IGNOREQUOTA if the response to LHLO specifies support and the
+    lmtp_ignore_quota option was set. */
+
+    sx->igquotstr = sx->peer_offered & OPTION_IGNQ ? US" IGNOREQUOTA" : US"";
+
+    /* If the response to EHLO specified support for the SIZE parameter, note
+    this, provided size_addition is non-negative. */
+
+    smtp_peer_options |= sx->peer_offered & OPTION_SIZE;
+
+    /* Note whether the server supports PIPELINING. If hosts_avoid_esmtp matched
+    the current host, esmtp will be false, so PIPELINING can never be used. If
+    the current host matches hosts_avoid_pipelining, don't do it. */
+
+    if (  sx->peer_offered & OPTION_PIPE
+       && verify_check_given_host(CUSS &ob->hosts_avoid_pipelining, sx->conn_args.host) != OK)
+      smtp_peer_options |= OPTION_PIPE;
+
+    DEBUG(D_transport) debug_printf("%susing PIPELINING\n",
+      smtp_peer_options & OPTION_PIPE ? "" : "not ");
+
+    if (  sx->peer_offered & OPTION_CHUNKING
+       && verify_check_given_host(CUSS &ob->hosts_try_chunking, sx->conn_args.host) != OK)
+      sx->peer_offered &= ~OPTION_CHUNKING;
+
+    if (sx->peer_offered & OPTION_CHUNKING)
+      DEBUG(D_transport) debug_printf("CHUNKING usable\n");
+
+#ifndef DISABLE_PRDR
+    if (  sx->peer_offered & OPTION_PRDR
+       && verify_check_given_host(CUSS &ob->hosts_try_prdr, sx->conn_args.host) != OK)
+      sx->peer_offered &= ~OPTION_PRDR;
+
+    if (sx->peer_offered & OPTION_PRDR)
+      DEBUG(D_transport) debug_printf("PRDR usable\n");
+#endif
+
+    /* Note if the server supports DSN */
+    smtp_peer_options |= sx->peer_offered & OPTION_DSN;
+    DEBUG(D_transport) debug_printf("%susing DSN\n",
+			sx->peer_offered & OPTION_DSN ? "" : "not ");
+
+#ifndef DISABLE_PIPE_CONNECT
+    if (  sx->early_pipe_ok
+       && !sx->early_pipe_active
+       && tls_out.active.sock >= 0
+       && smtp_peer_options & OPTION_PIPE
+       && ( sx->ehlo_resp.cleartext_features | sx->ehlo_resp.crypted_features)
+	  & OPTION_EARLY_PIPE)
+      {
+      DEBUG(D_transport) debug_printf("PIPE_CONNECT usable in future for this IP\n");
+      sx->ehlo_resp.crypted_auths = study_ehlo_auths(sx);
+      write_ehlo_cache_entry(sx);
+      }
+#endif
+
+    /* Note if the response to EHLO specifies support for the AUTH extension.
+    If it has, check that this host is one we want to authenticate to, and do
+    the business. The host name and address must be available when the
+    authenticator's client driver is running. */
+
+    switch (yield = smtp_auth(sx))
+      {
+      default:		goto SEND_QUIT;
+      case OK:		break;
+      case FAIL_SEND:	goto SEND_FAILED;
+      case FAIL:	goto RESPONSE_FAILED;
+      }
+    }
+  }
+sx->pipelining_used = pipelining_active = !!(smtp_peer_options & OPTION_PIPE);
+
+/* The setting up of the SMTP call is now complete. Any subsequent errors are
+message-specific. */
+
+sx->setting_up = FALSE;
+
+#ifdef SUPPORT_I18N
+if (sx->addrlist->prop.utf8_msg)
+  {
+  uschar * s;
+
+  /* If the transport sets a downconversion mode it overrides any set by ACL
+  for the message. */
+
+  if ((s = ob->utf8_downconvert))
+    {
+    if (!(s = expand_string(s)))
+      {
+      message = string_sprintf("failed to expand utf8_downconvert: %s",
+        expand_string_message);
+      set_errno_nohost(sx->addrlist, ERRNO_EXPANDFAIL, message, DEFER, FALSE, &sx->delivery_start);
+      yield = DEFER;
+      goto SEND_QUIT;
+      }
+    switch (*s)
+      {
+      case '1':	sx->addrlist->prop.utf8_downcvt = TRUE;
+		sx->addrlist->prop.utf8_downcvt_maybe = FALSE;
+		break;
+      case '0':	sx->addrlist->prop.utf8_downcvt = FALSE;
+		sx->addrlist->prop.utf8_downcvt_maybe = FALSE;
+		break;
+      case '-':	if (s[1] == '1')
+		  {
+		  sx->addrlist->prop.utf8_downcvt = FALSE;
+		  sx->addrlist->prop.utf8_downcvt_maybe = TRUE;
+		  }
+		break;
+      }
+    }
+
+  sx->utf8_needed = !sx->addrlist->prop.utf8_downcvt
+		    && !sx->addrlist->prop.utf8_downcvt_maybe;
+  DEBUG(D_transport) if (!sx->utf8_needed)
+    debug_printf("utf8: %s downconvert\n",
+      sx->addrlist->prop.utf8_downcvt ? "mandatory" : "optional");
+  }
+
+/* If this is an international message we need the host to speak SMTPUTF8 */
+if (sx->utf8_needed && !(sx->peer_offered & OPTION_UTF8))
+  {
+  errno = ERRNO_UTF8_FWD;
+  goto RESPONSE_FAILED;
+  }
+#endif	/*SUPPORT_I18N*/
+
+return OK;
+
+
+  {
+  int code;
+
+  RESPONSE_FAILED:
+    if (errno == ECONNREFUSED)	/* first-read error on a TFO conn */
+      {
+      /* There is a testing facility for simulating a connection timeout, as I
+      can't think of any other way of doing this. It converts a connection
+      refused into a timeout if the timeout is set to 999999.  This is done for
+      a 3whs connection in ip_connect(), but a TFO connection does not error
+      there - instead it gets ECONNREFUSED on the first data read.  Tracking
+      that a TFO really was done is too hard, or we would set a
+      sx->pending_conn_done bit and test that in smtp_reap_banner() and
+      smtp_reap_ehlo().  That would let us also add the conn-timeout to the
+      cmd-timeout. */
+
+      if (f.running_in_test_harness && ob->connect_timeout == 999999)
+	errno = ETIMEDOUT;
+      set_errno_nohost(sx->addrlist,
+	errno == ETIMEDOUT ? ERRNO_CONNECTTIMEOUT : errno,
+	sx->verify ? US strerror(errno) : NULL,
+	DEFER, FALSE, &sx->delivery_start);
+      sx->send_quit = FALSE;
+      return DEFER;
+      }
+
+    /* really an error on an SMTP read */
+    message = NULL;
+    sx->send_quit = check_response(sx->conn_args.host, &errno, sx->addrlist->more_errno,
+      sx->buffer, &code, &message, &pass_message);
+    yield = DEFER;
+    goto FAILED;
+
+  SEND_FAILED:
+    code = '4';
+    message = US string_sprintf("send() to %s [%s] failed: %s",
+      sx->conn_args.host->name, sx->conn_args.host->address, strerror(errno));
+    sx->send_quit = FALSE;
+    yield = DEFER;
+    goto FAILED;
+
+  EHLOHELO_FAILED:
+    code = '4';
+    message = string_sprintf("Remote host closed connection in response to %s"
+      " (EHLO response was: %s)", smtp_command, sx->buffer);
+    sx->send_quit = FALSE;
+    yield = DEFER;
+    goto FAILED;
+
+  /* This label is jumped to directly when a TLS negotiation has failed,
+  or was not done for a host for which it is required. Values will be set
+  in message and errno, and setting_up will always be true. Treat as
+  a temporary error. */
+
+#ifndef DISABLE_TLS
+  TLS_FAILED:
+    code = '4', yield = DEFER;
+    goto FAILED;
+#endif
+
+  /* The failure happened while setting up the call; see if the failure was
+  a 5xx response (this will either be on connection, or following HELO - a 5xx
+  after EHLO causes it to try HELO). If so, and there are no more hosts to try,
+  fail all addresses, as this host is never going to accept them. For other
+  errors during setting up (timeouts or whatever), defer all addresses, and
+  yield DEFER, so that the host is not tried again for a while.
+
+  XXX This peeking for another host feels like a layering violation. We want
+  to note the host as unusable, but down here we shouldn't know if this was
+  the last host to try for the addr(list).  Perhaps the upper layer should be
+  the one to do set_errno() ?  The problem is that currently the addr is where
+  errno etc. are stashed, but until we run out of hosts to try the errors are
+  host-specific.  Maybe we should enhance the host_item definition? */
+
+FAILED:
+  sx->ok = FALSE;                /* For when reached by GOTO */
+  set_errno(sx->addrlist, errno, message,
+	    sx->conn_args.host->next
+	    ? DEFER
+	    : code == '5'
+#ifdef SUPPORT_I18N
+			|| errno == ERRNO_UTF8_FWD
+#endif
+	    ? FAIL : DEFER,
+	    pass_message,
+	    errno == ECONNREFUSED ? NULL : sx->conn_args.host,
+#ifdef EXPERIMENTAL_DSN_INFO
+	    sx->smtp_greeting, sx->helo_response,
+#endif
+	    &sx->delivery_start);
+  }
+
+
+SEND_QUIT:
+
+if (sx->send_quit)
+  (void)smtp_write_command(sx, SCMD_FLUSH, "QUIT\r\n");
+
+#ifndef DISABLE_TLS
+if (sx->cctx.tls_ctx)
+  {
+  tls_close(sx->cctx.tls_ctx, TLS_SHUTDOWN_NOWAIT);
+  sx->cctx.tls_ctx = NULL;
+  }
+#endif
+
+/* Close the socket, and return the appropriate value, first setting
+works because the NULL setting is passed back to the calling process, and
+remote_max_parallel is forced to 1 when delivering over an existing connection,
+*/
+
+HDEBUG(D_transport|D_acl|D_v) debug_printf_indent("  SMTP(close)>>\n");
+if (sx->send_quit)
+  {
+  shutdown(sx->cctx.sock, SHUT_WR);
+  if (fcntl(sx->cctx.sock, F_SETFL, O_NONBLOCK) == 0)
+    for (int i = 16; read(sx->cctx.sock, sx->inbuffer, sizeof(sx->inbuffer)) > 0 && i > 0;)
+      i--;				/* drain socket */
+  sx->send_quit = FALSE;
+  }
+(void)close(sx->cctx.sock);
+sx->cctx.sock = -1;
+
+#ifndef DISABLE_EVENT
+(void) event_raise(sx->conn_args.tblock->event_action, US"tcp:close", NULL);
+#endif
+
+continue_transport = NULL;
+continue_hostname = NULL;
+return yield;
+}
+
+
+
+
+/* Create the string of options that will be appended to the MAIL FROM:
+in the connection context buffer */
+
+static int
+build_mailcmd_options(smtp_context * sx, address_item * addrlist)
+{
+uschar * p = sx->buffer;
+address_item * addr;
+int address_count;
+
+*p = 0;
+
+/* If we know the receiving MTA supports the SIZE qualification, and we know it,
+send it, adding something to the message size to allow for imprecision
+and things that get added en route. Exim keeps the number of lines
+in a message, so we can give an accurate value for the original message, but we
+need some additional to handle added headers. (Double "." characters don't get
+included in the count.) */
+
+if (  message_size > 0
+   && sx->peer_offered & OPTION_SIZE && !(sx->avoid_option & OPTION_SIZE))
+  {
+/*XXX problem here under spool_files_wireformat?
+Or just forget about lines?  Or inflate by a fixed proportion? */
+
+  sprintf(CS p, " SIZE=%d", message_size+message_linecount+(SOB sx->conn_args.ob)->size_addition);
+  while (*p) p++;
+  }
+
+#ifndef DISABLE_PRDR
+/* If it supports Per-Recipient Data Responses, and we have more than one recipient,
+request that */
+
+sx->prdr_active = FALSE;
+if (sx->peer_offered & OPTION_PRDR)
+  for (address_item * addr = addrlist; addr; addr = addr->next)
+    if (addr->transport_return == PENDING_DEFER)
+      {
+      for (addr = addr->next; addr; addr = addr->next)
+        if (addr->transport_return == PENDING_DEFER)
+	  {			/* at least two recipients to send */
+	  sx->prdr_active = TRUE;
+	  sprintf(CS p, " PRDR"); p += 5;
+	  break;
+	  }
+      break;
+      }
+#endif
+
+#ifdef SUPPORT_I18N
+/* If it supports internationalised messages, and this meesage need that,
+request it */
+
+if (  sx->peer_offered & OPTION_UTF8
+   && addrlist->prop.utf8_msg
+   && !addrlist->prop.utf8_downcvt
+   )
+  Ustrcpy(p, US" SMTPUTF8"), p += 9;
+#endif
+
+/* check if all addresses have DSN-lasthop flag; do not send RET and ENVID if so */
+for (sx->dsn_all_lasthop = TRUE, addr = addrlist, address_count = 0;
+     addr && address_count < sx->max_rcpt;
+     addr = addr->next) if (addr->transport_return == PENDING_DEFER)
+  {
+  address_count++;
+  if (!(addr->dsn_flags & rf_dsnlasthop))
+    {
+    sx->dsn_all_lasthop = FALSE;
+    break;
+    }
+  }
+
+/* Add any DSN flags to the mail command */
+
+if (sx->peer_offered & OPTION_DSN && !sx->dsn_all_lasthop)
+  {
+  if (dsn_ret == dsn_ret_hdrs)
+    { Ustrcpy(p, US" RET=HDRS"); p += 9; }
+  else if (dsn_ret == dsn_ret_full)
+    { Ustrcpy(p, US" RET=FULL"); p += 9; }
+
+  if (dsn_envid)
+    {
+    string_format(p, sizeof(sx->buffer) - (p-sx->buffer), " ENVID=%s", dsn_envid);
+    while (*p) p++;
+    }
+  }
+
+/* If an authenticated_sender override has been specified for this transport
+instance, expand it. If the expansion is forced to fail, and there was already
+an authenticated_sender for this message, the original value will be used.
+Other expansion failures are serious. An empty result is ignored, but there is
+otherwise no check - this feature is expected to be used with LMTP and other
+cases where non-standard addresses (e.g. without domains) might be required. */
+
+return smtp_mail_auth_str(sx, p, addrlist) ? ERROR : OK;
+}
+
+
+static void
+build_rcptcmd_options(smtp_context * sx, const address_item * addr)
+{
+uschar * p = sx->buffer;
+*p = 0;
+
+/* Add any DSN flags to the rcpt command */
+
+if (sx->peer_offered & OPTION_DSN && !(addr->dsn_flags & rf_dsnlasthop))
+  {
+  if (addr->dsn_flags & rf_dsnflags)
+    {
+    BOOL first = TRUE;
+
+    Ustrcpy(p, US" NOTIFY=");
+    while (*p) p++;
+    for (int i = 0; i < nelem(rf_list); i++) if (addr->dsn_flags & rf_list[i])
+      {
+      if (!first) *p++ = ',';
+      first = FALSE;
+      Ustrcpy(p, rf_names[i]);
+      while (*p) p++;
+      }
+    }
+
+  if (addr->dsn_orcpt)
+    {
+    string_format(p, sizeof(sx->buffer) - (p-sx->buffer), " ORCPT=%s",
+      addr->dsn_orcpt);
+    while (*p) p++;
+    }
+  }
+}
+
+
+
+/*
+Return:
+ 0	good, rcpt results in addr->transport_return (PENDING_OK, DEFER, FAIL)
+ -1	MAIL response error
+ -2	any non-MAIL read i/o error
+ -3	non-MAIL response timeout
+ -4	internal error; channel still usable
+ -5	transmit failed
+ */
+
+int
+smtp_write_mail_and_rcpt_cmds(smtp_context * sx, int * yield)
+{
+address_item * addr;
+int address_count, pipe_limit;
+int rc;
+
+if (build_mailcmd_options(sx, sx->first_addr) != OK)
+  {
+  *yield = ERROR;
+  return -4;
+  }
+
+/* From here until we send the DATA command, we can make use of PIPELINING
+if the server host supports it. The code has to be able to check the responses
+at any point, for when the buffer fills up, so we write it totally generally.
+When PIPELINING is off, each command written reports that it has flushed the
+buffer. */
+
+sx->pending_MAIL = TRUE;     /* The block starts with MAIL */
+
+  {
+  uschar * s = sx->from_addr;
+#ifdef SUPPORT_I18N
+  uschar * errstr = NULL;
+
+  /* If we must downconvert, do the from-address here.  Remember we had to
+  for the to-addresses (done below), and also (ugly) for re-doing when building
+  the delivery log line. */
+
+  if (  sx->addrlist->prop.utf8_msg
+     && (sx->addrlist->prop.utf8_downcvt || !(sx->peer_offered & OPTION_UTF8))
+     )
+    {
+    if (s = string_address_utf8_to_alabel(s, &errstr), errstr)
+      {
+      set_errno_nohost(sx->addrlist, ERRNO_EXPANDFAIL, errstr, DEFER, FALSE, &sx->delivery_start);
+      *yield = ERROR;
+      return -4;
+      }
+    setflag(sx->addrlist, af_utf8_downcvt);
+    }
+#endif
+
+  rc = smtp_write_command(sx, pipelining_active ? SCMD_BUFFER : SCMD_FLUSH,
+	  "MAIL FROM:<%s>%s\r\n", s, sx->buffer);
+  }
+
+mail_command = string_copy(big_buffer);  /* Save for later error message */
+
+switch(rc)
+  {
+  case -1:                /* Transmission error */
+    return -5;
+
+  case +1:                /* Cmd was sent */
+    if (!smtp_read_response(sx, sx->buffer, sizeof(sx->buffer), '2',
+       (SOB sx->conn_args.ob)->command_timeout))
+      {
+      if (errno == 0 && sx->buffer[0] == '4')
+	{
+	errno = ERRNO_MAIL4XX;
+	sx->addrlist->more_errno |= ((sx->buffer[1] - '0')*10 + sx->buffer[2] - '0') << 8;
+	}
+      return -1;
+      }
+    sx->pending_MAIL = FALSE;
+    break;
+
+  /* otherwise zero: command queued for pipeline */
+  }
+
+/* Pass over all the relevant recipient addresses for this host, which are the
+ones that have status PENDING_DEFER. If we are using PIPELINING, we can send
+several before we have to read the responses for those seen so far. This
+checking is done by a subroutine because it also needs to be done at the end.
+Send only up to max_rcpt addresses at a time, leaving next_addr pointing to
+the next one if not all are sent.
+
+In the MUA wrapper situation, we want to flush the PIPELINING buffer for the
+last address because we want to abort if any recipients have any kind of
+problem, temporary or permanent. We know that all recipient addresses will have
+the PENDING_DEFER status, because only one attempt is ever made, and we know
+that max_rcpt will be large, so all addresses will be done at once.
+
+For verify we flush the pipeline after any (the only) rcpt address. */
+
+for (addr = sx->first_addr, address_count = 0, pipe_limit = 100;
+     addr  &&  address_count < sx->max_rcpt;
+     addr = addr->next) if (addr->transport_return == PENDING_DEFER)
+  {
+  int cmds_sent;
+  BOOL no_flush;
+  uschar * rcpt_addr;
+
+  addr->dsn_aware = sx->peer_offered & OPTION_DSN
+    ? dsn_support_yes : dsn_support_no;
+
+  address_count++;
+  if (pipe_limit-- <= 0)
+    { no_flush = FALSE; pipe_limit = 100; }
+  else
+    no_flush = pipelining_active && !sx->verify
+	  && (!mua_wrapper || addr->next && address_count < sx->max_rcpt);
+
+  build_rcptcmd_options(sx, addr);
+
+  /* Now send the RCPT command, and process outstanding responses when
+  necessary. After a timeout on RCPT, we just end the function, leaving the
+  yield as OK, because this error can often mean that there is a problem with
+  just one address, so we don't want to delay the host. */
+
+  rcpt_addr = transport_rcpt_address(addr, sx->conn_args.tblock->rcpt_include_affixes);
+
+#ifdef SUPPORT_I18N
+  if (  testflag(sx->addrlist, af_utf8_downcvt)
+     && !(rcpt_addr = string_address_utf8_to_alabel(rcpt_addr, NULL))
+     )
+    {
+    /*XXX could we use a per-address errstr here? Not fail the whole send? */
+    errno = ERRNO_EXPANDFAIL;
+    return -5;		/*XXX too harsh? */
+    }
+#endif
+
+  cmds_sent = smtp_write_command(sx, no_flush ? SCMD_BUFFER : SCMD_FLUSH,
+    "RCPT TO:<%s>%s%s\r\n", rcpt_addr, sx->igquotstr, sx->buffer);
+
+  if (cmds_sent < 0) return -5;
+  if (cmds_sent > 0)
+    {
+    switch(sync_responses(sx, cmds_sent, 0))
+      {
+      case 3: sx->ok = TRUE;			/* 2xx & 5xx => OK & progress made */
+      case 2: sx->completed_addr = TRUE;	/* 5xx (only) => progress made */
+	      break;
+
+      case 1: sx->ok = TRUE;			/* 2xx (only) => OK, but if LMTP, */
+	      if (!sx->lmtp)			/*  can't tell about progress yet */
+		sx->completed_addr = TRUE;
+      case 0:					/* No 2xx or 5xx, but no probs */
+	      /* If any RCPT got a 452 response then next_addr has been updated
+	      for restarting with a new MAIL on the same connection.  Send no more
+	      RCPTs for this MAIL. */
+
+	      if (sx->RCPT_452)
+		{
+		DEBUG(D_transport) debug_printf("seen 452 too-many-rcpts\n");
+		sx->RCPT_452 = FALSE;
+		/* sx->next_addr has been reset for fast_retry */
+		return 0;
+		}
+	      break;
+
+      case -1: return -3;			/* Timeout on RCPT */
+      case -2: return -2;			/* non-MAIL read i/o error */
+      default: return -1;			/* any MAIL error */
+
+#ifndef DISABLE_PIPE_CONNECT
+      case -4: return -1;			/* non-2xx for pipelined banner or EHLO */
+      case -5: return -1;			/* TLS first-read error */
+#endif
+      }
+    }
+  }      /* Loop for next address */
+
+sx->next_addr = addr;
+return 0;
+}
+
+
+#ifndef DISABLE_TLS
+/*****************************************************
+* Proxy TLS connection for another transport process *
+******************************************************/
+/*
+Close the unused end of the pipe, fork once more, then use the given buffer
+as a staging area, and select on both the given fd and the TLS'd client-fd for
+data to read (per the coding in ip_recv() and fd_ready() this is legitimate).
+Do blocking full-size writes, and reads under a timeout.  Once both input
+channels are closed, exit the process.
+
+Arguments:
+  ct_ctx	tls context
+  buf		space to use for buffering
+  bufsiz	size of buffer
+  pfd		pipe filedescriptor array; [0] is comms to proxied process
+  timeout	per-read timeout, seconds
+
+Does not return.
+*/
+
+void
+smtp_proxy_tls(void * ct_ctx, uschar * buf, size_t bsize, int * pfd,
+  int timeout)
+{
+fd_set rfds, efds;
+int max_fd = MAX(pfd[0], tls_out.active.sock) + 1;
+int rc, i;
+
+close(pfd[1]);
+if ((rc = exim_fork(US"tls-proxy")))
+  _exit(rc < 0 ? EXIT_FAILURE : EXIT_SUCCESS);
+
+set_process_info("proxying TLS connection for continued transport");
+FD_ZERO(&rfds);
+FD_SET(tls_out.active.sock, &rfds);
+FD_SET(pfd[0], &rfds);
+
+for (int fd_bits = 3; fd_bits; )
+  {
+  time_t time_left = timeout;
+  time_t time_start = time(NULL);
+
+  /* wait for data */
+  efds = rfds;
+  do
+    {
+    struct timeval tv = { time_left, 0 };
+
+    rc = select(max_fd,
+      (SELECT_ARG2_TYPE *)&rfds, NULL, (SELECT_ARG2_TYPE *)&efds, &tv);
+
+    if (rc < 0 && errno == EINTR)
+      if ((time_left -= time(NULL) - time_start) > 0) continue;
+
+    if (rc <= 0)
+      {
+      DEBUG(D_transport) if (rc == 0) debug_printf("%s: timed out\n", __FUNCTION__);
+      goto done;
+      }
+
+    if (FD_ISSET(tls_out.active.sock, &efds) || FD_ISSET(pfd[0], &efds))
+      {
+      DEBUG(D_transport) debug_printf("select: exceptional cond on %s fd\n",
+	FD_ISSET(pfd[0], &efds) ? "proxy" : "tls");
+      goto done;
+      }
+    }
+  while (rc < 0 || !(FD_ISSET(tls_out.active.sock, &rfds) || FD_ISSET(pfd[0], &rfds)));
+
+  /* handle inbound data */
+  if (FD_ISSET(tls_out.active.sock, &rfds))
+    if ((rc = tls_read(ct_ctx, buf, bsize)) <= 0)
+      {
+      fd_bits &= ~1;
+      FD_CLR(tls_out.active.sock, &rfds);
+      shutdown(pfd[0], SHUT_WR);
+      timeout = 5;
+      }
+    else
+      {
+      for (int nbytes = 0; rc - nbytes > 0; nbytes += i)
+	if ((i = write(pfd[0], buf + nbytes, rc - nbytes)) < 0) goto done;
+      }
+  else if (fd_bits & 1)
+    FD_SET(tls_out.active.sock, &rfds);
+
+  /* handle outbound data */
+  if (FD_ISSET(pfd[0], &rfds))
+    if ((rc = read(pfd[0], buf, bsize)) <= 0)
+      {
+      fd_bits = 0;
+      tls_close(ct_ctx, TLS_SHUTDOWN_NOWAIT);
+      ct_ctx = NULL;
+      }
+    else
+      {
+      for (int nbytes = 0; rc - nbytes > 0; nbytes += i)
+	if ((i = tls_write(ct_ctx, buf + nbytes, rc - nbytes, FALSE)) < 0)
+	  goto done;
+      }
+  else if (fd_bits & 2)
+    FD_SET(pfd[0], &rfds);
+  }
+
+done:
+  testharness_pause_ms(100);	/* let logging complete */
+  exim_exit(EXIT_SUCCESS);
+}
+#endif
+
+
+/*************************************************
+*       Deliver address list to given host       *
+*************************************************/
+
+/* If continue_hostname is not null, we get here only when continuing to
+deliver down an existing channel. The channel was passed as the standard
+input. TLS is never active on a passed channel; the previous process either
+closes it down before passing the connection on, or inserts a TLS-proxy
+process and passes on a cleartext conection.
+
+Otherwise, we have to make a connection to the remote host, and do the
+initial protocol exchange.
+
+When running as an MUA wrapper, if the sender or any recipient is rejected,
+temporarily or permanently, we force failure for all recipients.
+
+Arguments:
+  addrlist        chain of potential addresses to deliver; only those whose
+                  transport_return field is set to PENDING_DEFER are currently
+                  being processed; others should be skipped - they have either
+                  been delivered to an earlier host or IP address, or been
+                  failed by one of them.
+  host            host to deliver to
+  host_af         AF_INET or AF_INET6
+  defport         default TCP/IP port to use if host does not specify, in host
+		  byte order
+  interface       interface to bind to, or NULL
+  tblock          transport instance block
+  message_defer   set TRUE if yield is OK, but all addresses were deferred
+                    because of a non-recipient, non-host failure, that is, a
+                    4xx response to MAIL FROM, DATA, or ".". This is a defer
+                    that is specific to the message.
+  suppress_tls    if TRUE, don't attempt a TLS connection - this is set for
+                    a second attempt after TLS initialization fails
+
+Returns:          OK    - the connection was made and the delivery attempted;
+                          the result for each address is in its data block.
+                  DEFER - the connection could not be made, or something failed
+                          while setting up the SMTP session, or there was a
+                          non-message-specific error, such as a timeout.
+                  ERROR - a filter command is specified for this transport,
+                          and there was a problem setting it up; OR helo_data
+                          or add_headers or authenticated_sender is specified
+                          for this transport, and the string failed to expand
+
+		For all non-OK returns the first addr of the list carries the
+		time taken for the attempt.
+*/
+
+static int
+smtp_deliver(address_item *addrlist, host_item *host, int host_af, int defport,
+  uschar *interface, transport_instance *tblock,
+  BOOL *message_defer, BOOL suppress_tls)
+{
+smtp_transport_options_block * ob = SOB tblock->options_block;
+int yield = OK;
+int save_errno;
+int rc;
+
+BOOL pass_message = FALSE;
+uschar *message = NULL;
+uschar new_message_id[MESSAGE_ID_LENGTH + 1];
+smtp_context * sx = store_get(sizeof(*sx), TRUE);	/* tainted, for the data buffers */
+#ifdef SUPPORT_DANE
+BOOL dane_held;
+#endif
+
+suppress_tls = suppress_tls;  /* stop compiler warning when no TLS support */
+*message_defer = FALSE;
+
+memset(sx, 0, sizeof(*sx));
+sx->addrlist = addrlist;
+sx->conn_args.host = host;
+sx->conn_args.host_af = host_af,
+sx->port = defport;
+sx->conn_args.interface = interface;
+sx->helo_data = NULL;
+sx->conn_args.tblock = tblock;
+/* sx->verify = FALSE; */
+gettimeofday(&sx->delivery_start, NULL);
+sx->sync_addr = sx->first_addr = addrlist;
+
+#ifdef SUPPORT_DANE
+DANE_DOMAINS:
+dane_held = FALSE;
+#endif
+
+/* Get the channel set up ready for a message, MAIL FROM being the next
+SMTP command to send. */
+
+if ((rc = smtp_setup_conn(sx, suppress_tls)) != OK)
+  {
+  timesince(&addrlist->delivery_time, &sx->delivery_start);
+  yield = rc;
+  goto TIDYUP;
+  }
+
+#ifdef SUPPORT_DANE
+/* If the connection used DANE, ignore for now any addresses with incompatible
+domains.  The SNI has to be the domain.  Arrange a whole new TCP conn later,
+just in case only TLS isn't enough. */
+
+if (sx->conn_args.dane)
+  {
+  const uschar * dane_domain = sx->first_addr->domain;
+
+  for (address_item * a = sx->first_addr->next; a; a = a->next)
+    if (  a->transport_return == PENDING_DEFER
+       && Ustrcmp(dane_domain, a->domain) != 0)
+      {
+      DEBUG(D_transport) debug_printf("DANE: holding %s for later\n", a->domain);
+      dane_held = TRUE;
+      a->transport_return = DANE;
+      }
+  }
+#endif
+
+/* If there is a filter command specified for this transport, we can now
+set it up. This cannot be done until the identity of the host is known. */
+
+if (tblock->filter_command)
+  {
+  transport_filter_timeout = tblock->filter_timeout;
+
+  /* On failure, copy the error to all addresses, abandon the SMTP call, and
+  yield ERROR. */
+
+  if (!transport_set_up_command(&transport_filter_argv,
+	tblock->filter_command, TRUE, DEFER, addrlist,
+	string_sprintf("%.50s transport", tblock->name), NULL))
+    {
+    set_errno_nohost(addrlist->next, addrlist->basic_errno, addrlist->message, DEFER,
+      FALSE, &sx->delivery_start);
+    yield = ERROR;
+    goto SEND_QUIT;
+    }
+
+  if (  transport_filter_argv
+     && *transport_filter_argv
+     && **transport_filter_argv
+     && sx->peer_offered & OPTION_CHUNKING
+#ifndef DISABLE_DKIM
+    /* When dkim signing, chunking is handled even with a transport-filter */
+     && !(ob->dkim.dkim_private_key && ob->dkim.dkim_domain && ob->dkim.dkim_selector)
+     && !ob->dkim.force_bodyhash
+#endif
+     )
+    {
+    sx->peer_offered &= ~OPTION_CHUNKING;
+    DEBUG(D_transport) debug_printf("CHUNKING not usable due to transport filter\n");
+    }
+  }
+
+/* For messages that have more than the maximum number of envelope recipients,
+we want to send several transactions down the same SMTP connection. (See
+comments in deliver.c as to how this reconciles, heuristically, with
+remote_max_parallel.) This optimization was added to Exim after the following
+code was already working. The simplest way to put it in without disturbing the
+code was to use a goto to jump back to this point when there is another
+transaction to handle. */
+
+SEND_MESSAGE:
+sx->from_addr = return_path;
+sx->sync_addr = sx->first_addr;
+sx->ok = FALSE;
+sx->send_rset = TRUE;
+sx->completed_addr = FALSE;
+
+
+/* If we are a continued-connection-after-verify the MAIL and RCPT
+commands were already sent; do not re-send but do mark the addrs as
+having been accepted up to RCPT stage.  A traditional cont-conn
+always has a sequence number greater than one. */
+
+if (continue_hostname && continue_sequence == 1)
+  {
+  /* sx->pending_MAIL = FALSE; */
+  sx->ok = TRUE;
+  /* sx->next_addr = NULL; */
+
+  for (address_item * addr = addrlist; addr; addr = addr->next)
+    addr->transport_return = PENDING_OK;
+  }
+else
+  {
+  /* Initiate a message transfer. */
+
+  switch(smtp_write_mail_and_rcpt_cmds(sx, &yield))
+    {
+    case 0:		break;
+    case -1: case -2:	goto RESPONSE_FAILED;
+    case -3:		goto END_OFF;
+    case -4:		goto SEND_QUIT;
+    default:		goto SEND_FAILED;
+    }
+
+  /* If we are an MUA wrapper, abort if any RCPTs were rejected, either
+  permanently or temporarily. We should have flushed and synced after the last
+  RCPT. */
+
+  if (mua_wrapper)
+    {
+    address_item * a;
+    unsigned cnt;
+
+    for (a = sx->first_addr, cnt = 0; a && cnt < sx->max_rcpt; a = a->next, cnt++)
+      if (a->transport_return != PENDING_OK)
+	{
+	/*XXX could we find a better errno than 0 here? */
+	set_errno_nohost(addrlist, 0, a->message, FAIL,
+	  testflag(a, af_pass_message), &sx->delivery_start);
+	sx->ok = FALSE;
+	break;
+	}
+    }
+  }
+
+/* If ok is TRUE, we know we have got at least one good recipient, and must now
+send DATA, but if it is FALSE (in the normal, non-wrapper case), we may still
+have a good recipient buffered up if we are pipelining. We don't want to waste
+time sending DATA needlessly, so we only send it if either ok is TRUE or if we
+are pipelining. The responses are all handled by sync_responses().
+If using CHUNKING, do not send a BDAT until we know how big a chunk we want
+to send is. */
+
+if (  !(sx->peer_offered & OPTION_CHUNKING)
+   && (sx->ok || (pipelining_active && !mua_wrapper)))
+  {
+  int count = smtp_write_command(sx, SCMD_FLUSH, "DATA\r\n");
+
+  if (count < 0) goto SEND_FAILED;
+  switch(sync_responses(sx, count, sx->ok ? +1 : -1))
+    {
+    case 3: sx->ok = TRUE;            /* 2xx & 5xx => OK & progress made */
+    case 2: sx->completed_addr = TRUE;    /* 5xx (only) => progress made */
+    break;
+
+    case 1: sx->ok = TRUE;            /* 2xx (only) => OK, but if LMTP, */
+    if (!sx->lmtp) sx->completed_addr = TRUE; /* can't tell about progress yet */
+    case 0: break;			/* No 2xx or 5xx, but no probs */
+
+    case -1: goto END_OFF;		/* Timeout on RCPT */
+
+#ifndef DISABLE_PIPE_CONNECT
+    case -5:				/* TLS first-read error */
+    case -4:  HDEBUG(D_transport)
+		debug_printf("failed reaping pipelined cmd responses\n");
+#endif
+    default: goto RESPONSE_FAILED;       /* I/O error, or any MAIL/DATA error */
+    }
+  pipelining_active = FALSE;
+  data_command = string_copy(big_buffer);  /* Save for later error message */
+  }
+
+/* If there were no good recipients (but otherwise there have been no
+problems), just set ok TRUE, since we have handled address-specific errors
+already. Otherwise, it's OK to send the message. Use the check/escape mechanism
+for handling the SMTP dot-handling protocol, flagging to apply to headers as
+well as body. Set the appropriate timeout value to be used for each chunk.
+(Haven't been able to make it work using select() for writing yet.) */
+
+if (  !sx->ok
+   && (!(sx->peer_offered & OPTION_CHUNKING) || !pipelining_active))
+  {
+  /* Save the first address of the next batch. */
+  sx->first_addr = sx->next_addr;
+
+  sx->ok = TRUE;
+  }
+else
+  {
+  transport_ctx tctx = {
+    .u = {.fd = sx->cctx.sock},	/*XXX will this need TLS info? */
+    .tblock =	tblock,
+    .addr =	addrlist,
+    .check_string = US".",
+    .escape_string = US"..",	/* Escaping strings */
+    .options =
+      topt_use_crlf | topt_escape_headers
+    | (tblock->body_only	? topt_no_headers : 0)
+    | (tblock->headers_only	? topt_no_body : 0)
+    | (tblock->return_path_add	? topt_add_return_path : 0)
+    | (tblock->delivery_date_add ? topt_add_delivery_date : 0)
+    | (tblock->envelope_to_add	? topt_add_envelope_to : 0)
+  };
+
+  /* If using CHUNKING we need a callback from the generic transport
+  support to us, for the sending of BDAT smtp commands and the reaping
+  of responses.  The callback needs a whole bunch of state so set up
+  a transport-context structure to be passed around. */
+
+  if (sx->peer_offered & OPTION_CHUNKING)
+    {
+    tctx.check_string = tctx.escape_string = NULL;
+    tctx.options |= topt_use_bdat;
+    tctx.chunk_cb = smtp_chunk_cmd_callback;
+    sx->pending_BDAT = FALSE;
+    sx->good_RCPT = sx->ok;
+    sx->cmd_count = 0;
+    tctx.smtp_context = sx;
+    }
+  else
+    tctx.options |= topt_end_dot;
+
+  /* Save the first address of the next batch. */
+  sx->first_addr = sx->next_addr;
+
+  /* Responses from CHUNKING commands go in buffer.  Otherwise,
+  there has not been a response. */
+
+  sx->buffer[0] = 0;
+
+  sigalrm_seen = FALSE;
+  transport_write_timeout = ob->data_timeout;
+  smtp_command = US"sending data block";   /* For error messages */
+  DEBUG(D_transport|D_v)
+    if (sx->peer_offered & OPTION_CHUNKING)
+      debug_printf("         will write message using CHUNKING\n");
+    else
+      debug_printf("  SMTP>> writing message and terminating \".\"\n");
+  transport_count = 0;
+
+#ifndef DISABLE_DKIM
+  {
+# ifdef MEASURE_TIMING
+  struct timeval t0;
+  gettimeofday(&t0, NULL);
+# endif
+  dkim_exim_sign_init();
+# ifdef EXPERIMENTAL_ARC
+    {
+    uschar * s = ob->arc_sign;
+    if (s)
+      {
+      if (!(ob->dkim.arc_signspec = s = expand_string(s)))
+	{
+	if (!f.expand_string_forcedfail)
+	  {
+	  message = US"failed to expand arc_sign";
+	  sx->ok = FALSE;
+	  goto SEND_FAILED;
+	  }
+	}
+      else if (*s)
+	{
+	/* Ask dkim code to hash the body for ARC */
+	(void) arc_ams_setup_sign_bodyhash();
+	ob->dkim.force_bodyhash = TRUE;
+	}
+      }
+    }
+# endif
+# ifdef MEASURE_TIMING
+  report_time_since(&t0, US"dkim_exim_sign_init (delta)");
+# endif
+  }
+  sx->ok = dkim_transport_write_message(&tctx, &ob->dkim, CUSS &message);
+#else
+  sx->ok = transport_write_message(&tctx, 0);
+#endif
+
+  /* transport_write_message() uses write() because it is called from other
+  places to write to non-sockets. This means that under some OS (e.g. Solaris)
+  it can exit with "Broken pipe" as its error. This really means that the
+  socket got closed at the far end. */
+
+  transport_write_timeout = 0;   /* for subsequent transports */
+
+  /* Failure can either be some kind of I/O disaster (including timeout),
+  or the failure of a transport filter or the expansion of added headers.
+  Or, when CHUNKING, it can be a protocol-detected failure. */
+
+  if (!sx->ok)
+    if (message) goto SEND_FAILED;
+    else         goto RESPONSE_FAILED;
+
+  /* We used to send the terminating "." explicitly here, but because of
+  buffering effects at both ends of TCP/IP connections, you don't gain
+  anything by keeping it separate, so it might as well go in the final
+  data buffer for efficiency. This is now done by setting the topt_end_dot
+  flag above. */
+
+  smtp_command = US"end of data";
+
+  if (sx->peer_offered & OPTION_CHUNKING && sx->cmd_count > 1)
+    {
+    /* Reap any outstanding MAIL & RCPT commands, but not a DATA-go-ahead */
+    switch(sync_responses(sx, sx->cmd_count-1, 0))
+      {
+      case 3: sx->ok = TRUE;            /* 2xx & 5xx => OK & progress made */
+      case 2: sx->completed_addr = TRUE;    /* 5xx (only) => progress made */
+	      break;
+
+      case 1: sx->ok = TRUE;		/* 2xx (only) => OK, but if LMTP, */
+      if (!sx->lmtp) sx->completed_addr = TRUE; /* can't tell about progress yet */
+      case 0: break;			/* No 2xx or 5xx, but no probs */
+
+      case -1: goto END_OFF;		/* Timeout on RCPT */
+
+#ifndef DISABLE_PIPE_CONNECT
+      case -5:				/* TLS first-read error */
+      case -4:  HDEBUG(D_transport)
+		  debug_printf("failed reaping pipelined cmd responses\n");
+#endif
+      default: goto RESPONSE_FAILED;	/* I/O error, or any MAIL/DATA error */
+      }
+    }
+
+#ifndef DISABLE_PRDR
+  /* For PRDR we optionally get a partial-responses warning followed by the
+  individual responses, before going on with the overall response.  If we don't
+  get the warning then deal with per non-PRDR. */
+
+  if(sx->prdr_active)
+    {
+    sx->ok = smtp_read_response(sx, sx->buffer, sizeof(sx->buffer), '3', ob->final_timeout);
+    if (!sx->ok && errno == 0) switch(sx->buffer[0])
+      {
+      case '2': sx->prdr_active = FALSE;
+		sx->ok = TRUE;
+		break;
+      case '4': errno = ERRNO_DATA4XX;
+		addrlist->more_errno |=
+		  ((sx->buffer[1] - '0')*10 + sx->buffer[2] - '0') << 8;
+		break;
+      }
+    }
+  else
+#endif
+
+  /* For non-PRDR SMTP, we now read a single response that applies to the
+  whole message.  If it is OK, then all the addresses have been delivered. */
+
+  if (!sx->lmtp)
+    {
+    sx->ok = smtp_read_response(sx, sx->buffer, sizeof(sx->buffer), '2',
+      ob->final_timeout);
+    if (!sx->ok && errno == 0 && sx->buffer[0] == '4')
+      {
+      errno = ERRNO_DATA4XX;
+      addrlist->more_errno |= ((sx->buffer[1] - '0')*10 + sx->buffer[2] - '0') << 8;
+      }
+    }
+
+  /* For LMTP, we get back a response for every RCPT command that we sent;
+  some may be accepted and some rejected. For those that get a response, their
+  status is fixed; any that are accepted have been handed over, even if later
+  responses crash - at least, that's how I read RFC 2033.
+
+  If all went well, mark the recipient addresses as completed, record which
+  host/IPaddress they were delivered to, and cut out RSET when sending another
+  message down the same channel. Write the completed addresses to the journal
+  now so that they are recorded in case there is a crash of hardware or
+  software before the spool gets updated. Also record the final SMTP
+  confirmation if needed (for SMTP only). */
+
+  if (sx->ok)
+    {
+    int flag = '=';
+    struct timeval delivery_time;
+    int len;
+    uschar * conf = NULL;
+
+    timesince(&delivery_time, &sx->delivery_start);
+    sx->send_rset = FALSE;
+    pipelining_active = FALSE;
+
+    /* Set up confirmation if needed - applies only to SMTP */
+
+    if (
+#ifdef DISABLE_EVENT
+          LOGGING(smtp_confirmation) &&
+#endif
+          !sx->lmtp
+       )
+      {
+      const uschar *s = string_printing(sx->buffer);
+      /* deconst cast ok here as string_printing was checked to have alloc'n'copied */
+      conf = (s == sx->buffer)? US string_copy(s) : US s;
+      }
+
+    /* Process all transported addresses - for LMTP or PRDR, read a status for
+    each one. We used to drop out at first_addr, until someone returned a 452
+    followed by a 250... and we screwed up the accepted addresses. */
+
+    for (address_item * addr = addrlist; addr; addr = addr->next)
+      {
+      if (addr->transport_return != PENDING_OK) continue;
+
+      /* LMTP - if the response fails badly (e.g. timeout), use it for all the
+      remaining addresses. Otherwise, it's a return code for just the one
+      address. For temporary errors, add a retry item for the address so that
+      it doesn't get tried again too soon. */
+
+#ifndef DISABLE_PRDR
+      if (sx->lmtp || sx->prdr_active)
+#else
+      if (sx->lmtp)
+#endif
+        {
+        if (!smtp_read_response(sx, sx->buffer, sizeof(sx->buffer), '2',
+            ob->final_timeout))
+          {
+          if (errno != 0 || sx->buffer[0] == 0) goto RESPONSE_FAILED;
+          addr->message = string_sprintf(
+#ifndef DISABLE_PRDR
+	    "%s error after %s: %s", sx->prdr_active ? "PRDR":"LMTP",
+#else
+	    "LMTP error after %s: %s",
+#endif
+	    data_command, string_printing(sx->buffer));
+          setflag(addr, af_pass_message);   /* Allow message to go to user */
+          if (sx->buffer[0] == '5')
+            addr->transport_return = FAIL;
+          else
+            {
+            errno = ERRNO_DATA4XX;
+            addr->more_errno |= ((sx->buffer[1] - '0')*10 + sx->buffer[2] - '0') << 8;
+            addr->transport_return = DEFER;
+#ifndef DISABLE_PRDR
+            if (!sx->prdr_active)
+#endif
+              retry_add_item(addr, addr->address_retry_key, 0);
+            }
+          continue;
+          }
+        sx->completed_addr = TRUE;   /* NOW we can set this flag */
+        if (LOGGING(smtp_confirmation))
+          {
+          const uschar *s = string_printing(sx->buffer);
+	  /* deconst cast ok here as string_printing was checked to have alloc'n'copied */
+          conf = (s == sx->buffer) ? US string_copy(s) : US s;
+          }
+        }
+
+      /* SMTP, or success return from LMTP for this address. Pass back the
+      actual host that was used. */
+
+      addr->transport_return = OK;
+      addr->host_used = host;
+      addr->delivery_time = delivery_time;
+      addr->special_action = flag;
+      addr->message = conf;
+
+      if (tcp_out_fastopen)
+	{
+	setflag(addr, af_tcp_fastopen_conn);
+	if (tcp_out_fastopen >= TFO_USED_NODATA) setflag(addr, af_tcp_fastopen);
+	if (tcp_out_fastopen >= TFO_USED_DATA) setflag(addr, af_tcp_fastopen_data);
+	}
+      if (sx->pipelining_used) setflag(addr, af_pipelining);
+#ifndef DISABLE_PIPE_CONNECT
+      if (sx->early_pipe_active) setflag(addr, af_early_pipe);
+#endif
+#ifndef DISABLE_PRDR
+      if (sx->prdr_active) setflag(addr, af_prdr_used);
+#endif
+      if (sx->peer_offered & OPTION_CHUNKING) setflag(addr, af_chunking_used);
+      flag = '-';
+
+#ifndef DISABLE_PRDR
+      if (!sx->prdr_active)
+#endif
+        {
+        /* Update the journal. For homonymic addresses, use the base address plus
+        the transport name. See lots of comments in deliver.c about the reasons
+        for the complications when homonyms are involved. Just carry on after
+        write error, as it may prove possible to update the spool file later. */
+
+        if (testflag(addr, af_homonym))
+          sprintf(CS sx->buffer, "%.500s/%s\n", addr->unique + 3, tblock->name);
+        else
+          sprintf(CS sx->buffer, "%.500s\n", addr->unique);
+
+        DEBUG(D_deliver) debug_printf("S:journalling %s\n", sx->buffer);
+        len = Ustrlen(CS sx->buffer);
+        if (write(journal_fd, sx->buffer, len) != len)
+          log_write(0, LOG_MAIN|LOG_PANIC, "failed to write journal for "
+            "%s: %s", sx->buffer, strerror(errno));
+        }
+      }
+
+#ifndef DISABLE_PRDR
+    if (sx->prdr_active)
+      {
+      const uschar * overall_message;
+
+      /* PRDR - get the final, overall response.  For any non-success
+      upgrade all the address statuses. */
+
+      sx->ok = smtp_read_response(sx, sx->buffer, sizeof(sx->buffer), '2',
+	ob->final_timeout);
+      if (!sx->ok)
+	{
+	if(errno == 0 && sx->buffer[0] == '4')
+	  {
+	  errno = ERRNO_DATA4XX;
+	  addrlist->more_errno |= ((sx->buffer[1] - '0')*10 + sx->buffer[2] - '0') << 8;
+	  }
+	for (address_item * addr = addrlist; addr != sx->first_addr; addr = addr->next)
+	  if (sx->buffer[0] == '5' || addr->transport_return == OK)
+	    addr->transport_return = PENDING_OK; /* allow set_errno action */
+	goto RESPONSE_FAILED;
+	}
+
+      /* Append the overall response to the individual PRDR response for logging
+      and update the journal, or setup retry. */
+
+      overall_message = string_printing(sx->buffer);
+      for (address_item * addr = addrlist; addr != sx->first_addr; addr = addr->next)
+	if (addr->transport_return == OK)
+	  addr->message = string_sprintf("%s\\n%s", addr->message, overall_message);
+
+      for (address_item * addr = addrlist; addr != sx->first_addr; addr = addr->next)
+	if (addr->transport_return == OK)
+	  {
+	  if (testflag(addr, af_homonym))
+	    sprintf(CS sx->buffer, "%.500s/%s\n", addr->unique + 3, tblock->name);
+	  else
+	    sprintf(CS sx->buffer, "%.500s\n", addr->unique);
+
+	  DEBUG(D_deliver) debug_printf("journalling(PRDR) %s\n", sx->buffer);
+	  len = Ustrlen(CS sx->buffer);
+	  if (write(journal_fd, sx->buffer, len) != len)
+	    log_write(0, LOG_MAIN|LOG_PANIC, "failed to write journal for "
+	      "%s: %s", sx->buffer, strerror(errno));
+	  }
+	else if (addr->transport_return == DEFER)
+	  retry_add_item(addr, addr->address_retry_key, -2);
+      }
+#endif
+
+    /* Ensure the journal file is pushed out to disk. */
+
+    if (EXIMfsync(journal_fd) < 0)
+      log_write(0, LOG_MAIN|LOG_PANIC, "failed to fsync journal: %s",
+        strerror(errno));
+    }
+  }
+
+
+/* Handle general (not specific to one address) failures here. The value of ok
+is used to skip over this code on the falling through case. A timeout causes a
+deferral. Other errors may defer or fail according to the response code, and
+may set up a special errno value, e.g. after connection chopped, which is
+assumed if errno == 0 and there is no text in the buffer. If control reaches
+here during the setting up phase (i.e. before MAIL FROM) then always defer, as
+the problem is not related to this specific message. */
+
+if (!sx->ok)
+  {
+  int code, set_rc;
+  uschar * set_message;
+
+  RESPONSE_FAILED:
+    {
+    save_errno = errno;
+    message = NULL;
+    sx->send_quit = check_response(host, &save_errno, addrlist->more_errno,
+      sx->buffer, &code, &message, &pass_message);
+    goto FAILED;
+    }
+
+  SEND_FAILED:
+    {
+    save_errno = errno;
+    code = '4';
+    message = string_sprintf("send() to %s [%s] failed: %s",
+      host->name, host->address, message ? message : US strerror(save_errno));
+    sx->send_quit = FALSE;
+    goto FAILED;
+    }
+
+  FAILED:
+    {
+    BOOL message_error;
+
+    sx->ok = FALSE;                /* For when reached by GOTO */
+    set_message = message;
+
+  /* We want to handle timeouts after MAIL or "." and loss of connection after
+  "." specially. They can indicate a problem with the sender address or with
+  the contents of the message rather than a real error on the connection. These
+  cases are treated in the same way as a 4xx response. This next bit of code
+  does the classification. */
+
+    switch(save_errno)
+      {
+      case 0:
+      case ERRNO_MAIL4XX:
+      case ERRNO_DATA4XX:
+	message_error = TRUE;
+	break;
+
+      case ETIMEDOUT:
+	message_error = Ustrncmp(smtp_command,"MAIL",4) == 0 ||
+			Ustrncmp(smtp_command,"end ",4) == 0;
+	break;
+
+      case ERRNO_SMTPCLOSED:
+	message_error = Ustrncmp(smtp_command,"end ",4) == 0;
+	break;
+
+      default:
+	message_error = FALSE;
+	break;
+      }
+
+    /* Handle the cases that are treated as message errors. These are:
+
+      (a) negative response or timeout after MAIL
+      (b) negative response after DATA
+      (c) negative response or timeout or dropped connection after "."
+      (d) utf8 support required and not offered
+
+    It won't be a negative response or timeout after RCPT, as that is dealt
+    with separately above. The action in all cases is to set an appropriate
+    error code for all the addresses, but to leave yield set to OK because the
+    host itself has not failed. Of course, it might in practice have failed
+    when we've had a timeout, but if so, we'll discover that at the next
+    delivery attempt. For a temporary error, set the message_defer flag, and
+    write to the logs for information if this is not the last host. The error
+    for the last host will be logged as part of the address's log line. */
+
+    if (message_error)
+      {
+      if (mua_wrapper) code = '5';  /* Force hard failure in wrapper mode */
+
+      /* If there's an errno, the message contains just the identity of
+      the host. */
+
+      if (code == '5')
+	set_rc = FAIL;
+      else		/* Anything other than 5 is treated as temporary */
+        {
+	set_rc = DEFER;
+        if (save_errno > 0)
+          message = US string_sprintf("%s: %s", message, strerror(save_errno));
+
+        write_logs(host, message, sx->first_addr ? sx->first_addr->basic_errno : 0);
+
+        *message_defer = TRUE;
+        }
+      }
+
+    /* Otherwise, we have an I/O error or a timeout other than after MAIL or
+    ".", or some other transportation error. We defer all addresses and yield
+    DEFER, except for the case of failed add_headers expansion, or a transport
+    filter failure, when the yield should be ERROR, to stop it trying other
+    hosts. */
+
+    else
+      {
+#ifndef DISABLE_PIPE_CONNECT
+      /* If we were early-pipelinng and the actual EHLO response did not match
+      the cached value we assumed, we could have detected it and passed a
+      custom errno through to here.  It would be nice to RSET and retry right
+      away, but to reliably do that we eould need an extra synch point before
+      we committed to data and that would discard half the gained roundrips.
+      Or we could summarily drop the TCP connection. but that is also ugly.
+      Instead, we ignore the possibility (having freshened the cache) and rely
+      on the server telling us with a nonmessage error if we have tried to
+      do something it no longer supports. */
+#endif
+      set_rc = DEFER;
+      yield = (save_errno == ERRNO_CHHEADER_FAIL ||
+               save_errno == ERRNO_FILTER_FAIL) ? ERROR : DEFER;
+      }
+    }
+
+  set_errno(addrlist, save_errno, set_message, set_rc, pass_message, host,
+#ifdef EXPERIMENTAL_DSN_INFO
+	    sx->smtp_greeting, sx->helo_response,
+#endif
+	    &sx->delivery_start);
+  }
+
+/* If all has gone well, send_quit will be set TRUE, implying we can end the
+SMTP session tidily. However, if there were too many addresses to send in one
+message (indicated by first_addr being non-NULL) we want to carry on with the
+rest of them. Also, it is desirable to send more than one message down the SMTP
+connection if there are several waiting, provided we haven't already sent so
+many as to hit the configured limit. The function transport_check_waiting looks
+for a waiting message and returns its id. Then transport_pass_socket tries to
+set up a continued delivery by passing the socket on to another process. The
+variable send_rset is FALSE if a message has just been successfully transferred.
+
+If we are already sending down a continued channel, there may be further
+addresses not yet delivered that are aimed at the same host, but which have not
+been passed in this run of the transport. In this case, continue_more will be
+true, and all we should do is send RSET if necessary, and return, leaving the
+channel open.
+
+However, if no address was disposed of, i.e. all addresses got 4xx errors, we
+do not want to continue with other messages down the same channel, because that
+can lead to looping between two or more messages, all with the same,
+temporarily failing address(es). [The retry information isn't updated yet, so
+new processes keep on trying.] We probably also don't want to try more of this
+message's addresses either.
+
+If we have started a TLS session, we have to end it before passing the
+connection to a new process. However, not all servers can handle this (Exim
+can), so we do not pass such a connection on if the host matches
+hosts_nopass_tls. */
+
+DEBUG(D_transport)
+  debug_printf("ok=%d send_quit=%d send_rset=%d continue_more=%d "
+    "yield=%d first_address is %sNULL\n", sx->ok, sx->send_quit,
+    sx->send_rset, f.continue_more, yield, sx->first_addr ? "not " : "");
+
+if (sx->completed_addr && sx->ok && sx->send_quit)
+  {
+  BOOL more;
+  smtp_compare_t t_compare;
+
+  t_compare.tblock = tblock;
+  t_compare.current_sender_address = sender_address;
+
+  if (  sx->first_addr != NULL		/* more addrs for this message */
+     || f.continue_more			/* more addrs for coninued-host */
+     || (
+#ifndef DISABLE_TLS
+	   (  tls_out.active.sock < 0  &&  !continue_proxy_cipher
+           || verify_check_given_host(CUSS &ob->hosts_nopass_tls, host) != OK
+	   )
+        &&
+#endif
+           transport_check_waiting(tblock->name, host->name,
+             tblock->connection_max_messages, new_message_id, &more,
+	     (oicf)smtp_are_same_identities, (void*)&t_compare)
+     )  )
+    {
+    uschar *msg;
+    BOOL pass_message;
+
+    if (sx->send_rset)
+      if (! (sx->ok = smtp_write_command(sx, SCMD_FLUSH, "RSET\r\n") >= 0))
+        {
+        msg = US string_sprintf("send() to %s [%s] failed: %s", host->name,
+          host->address, strerror(errno));
+        sx->send_quit = FALSE;
+        }
+      else if (! (sx->ok = smtp_read_response(sx, sx->buffer, sizeof(sx->buffer),
+		  '2', ob->command_timeout)))
+        {
+        int code;
+        sx->send_quit = check_response(host, &errno, 0, sx->buffer, &code, &msg,
+          &pass_message);
+        if (!sx->send_quit)
+          {
+          DEBUG(D_transport) debug_printf("H=%s [%s] %s\n",
+	    host->name, host->address, msg);
+          }
+        }
+
+    /* Either RSET was not needed, or it succeeded */
+
+    if (sx->ok)
+      {
+#ifndef DISABLE_TLS
+      int pfd[2];
+#endif
+      int socket_fd = sx->cctx.sock;
+
+
+      if (sx->first_addr != NULL)	/* More addresses still to be sent */
+        {				/*   for this message              */
+        continue_sequence++;		/* Causes * in logging */
+	pipelining_active = sx->pipelining_used;    /* was cleared at DATA */
+        goto SEND_MESSAGE;
+        }
+
+      /* Unless caller said it already has more messages listed for this host,
+      pass the connection on to a new Exim process (below, the call to
+      transport_pass_socket).  If the caller has more ready, just return with
+      the connection still open. */
+
+#ifndef DISABLE_TLS
+      if (tls_out.active.sock >= 0)
+	if (  f.continue_more
+	   || verify_check_given_host(CUSS &ob->hosts_noproxy_tls, host) == OK)
+	  {
+	  /* Before passing the socket on, or returning to caller with it still
+	  open, we must shut down TLS.  Not all MTAs allow for the continuation
+	  of the SMTP session when TLS is shut down. We test for this by sending
+	  a new EHLO. If we don't get a good response, we don't attempt to pass
+	  the socket on. */
+
+	  tls_close(sx->cctx.tls_ctx, TLS_SHUTDOWN_WAIT);
+	  sx->cctx.tls_ctx = NULL;
+	  tls_out.active.sock = -1;
+	  smtp_peer_options = smtp_peer_options_wrap;
+	  sx->ok = !sx->smtps
+	    && smtp_write_command(sx, SCMD_FLUSH, "EHLO %s\r\n", sx->helo_data)
+		>= 0
+	    && smtp_read_response(sx, sx->buffer, sizeof(sx->buffer),
+				      '2', ob->command_timeout);
+
+	  if (sx->ok && f.continue_more)
+	    goto TIDYUP;		/* More addresses for another run */
+	  }
+	else
+	  {
+	  /* Set up a pipe for proxying TLS for the new transport process */
+
+	  smtp_peer_options |= OPTION_TLS;
+	  if ((sx->ok = socketpair(AF_UNIX, SOCK_STREAM, 0, pfd) == 0))
+	    socket_fd = pfd[1];
+	  else
+	    set_errno(sx->first_addr, errno, US"internal allocation problem",
+		    DEFER, FALSE, host,
+# ifdef EXPERIMENTAL_DSN_INFO
+		    sx->smtp_greeting, sx->helo_response,
+# endif
+		    &sx->delivery_start);
+	  }
+      else
+#endif
+	if (f.continue_more)
+	  goto TIDYUP;			/* More addresses for another run */
+
+      /* If the socket is successfully passed, we mustn't send QUIT (or
+      indeed anything!) from here. */
+
+/*XXX DSN_INFO: assume likely to do new HELO; but for greet we'll want to
+propagate it from the initial
+*/
+      if (sx->ok && transport_pass_socket(tblock->name, host->name,
+	    host->address, new_message_id, socket_fd))
+	{
+        sx->send_quit = FALSE;
+
+	/* We have passed the client socket to a fresh transport process.
+	If TLS is still active, we need to proxy it for the transport we
+	just passed the baton to.  Fork a child to to do it, and return to
+	get logging done asap.  Which way to place the work makes assumptions
+	about post-fork prioritisation which may not hold on all platforms. */
+#ifndef DISABLE_TLS
+	if (tls_out.active.sock >= 0)
+	  {
+	  int pid = exim_fork(US"tls-proxy-interproc");
+	  if (pid == 0)		/* child; fork again to disconnect totally */
+	    {
+	    /* does not return */
+	    smtp_proxy_tls(sx->cctx.tls_ctx, sx->buffer, sizeof(sx->buffer), pfd,
+			    ob->command_timeout);
+	    }
+
+	  if (pid > 0)		/* parent */
+	    {
+	    close(pfd[0]);
+	    /* tidy the inter-proc to disconn the proxy proc */
+	    waitpid(pid, NULL, 0);
+	    tls_close(sx->cctx.tls_ctx, TLS_NO_SHUTDOWN);
+	    sx->cctx.tls_ctx = NULL;
+	    (void)close(sx->cctx.sock);
+	    sx->cctx.sock = -1;
+	    continue_transport = NULL;
+	    continue_hostname = NULL;
+	    goto TIDYUP;
+	    }
+	  log_write(0, LOG_PANIC_DIE, "fork failed");
+	  }
+#endif
+	}
+      }
+
+    /* If RSET failed and there are addresses left, they get deferred. */
+    else
+      set_errno(sx->first_addr, errno, msg, DEFER, FALSE, host,
+#ifdef EXPERIMENTAL_DSN_INFO
+		  sx->smtp_greeting, sx->helo_response,
+#endif
+		  &sx->delivery_start);
+    }
+  }
+
+/* End off tidily with QUIT unless the connection has died or the socket has
+been passed to another process. There has been discussion on the net about what
+to do after sending QUIT. The wording of the RFC suggests that it is necessary
+to wait for a response, but on the other hand, there isn't anything one can do
+with an error response, other than log it. Exim used to do that. However,
+further discussion suggested that it is positively advantageous not to wait for
+the response, but to close the session immediately. This is supposed to move
+the TCP/IP TIME_WAIT state from the server to the client, thereby removing some
+load from the server. (Hosts that are both servers and clients may not see much
+difference, of course.) Further discussion indicated that this was safe to do
+on Unix systems which have decent implementations of TCP/IP that leave the
+connection around for a while (TIME_WAIT) after the application has gone away.
+This enables the response sent by the server to be properly ACKed rather than
+timed out, as can happen on broken TCP/IP implementations on other OS.
+
+This change is being made on 31-Jul-98. After over a year of trouble-free
+operation, the old commented-out code was removed on 17-Sep-99. */
+
+SEND_QUIT:
+#ifdef TCP_CORK
+(void) setsockopt(sx->cctx.sock, IPPROTO_TCP, TCP_CORK, US &on, sizeof(on));
+#endif
+if (sx->send_quit) (void)smtp_write_command(sx, SCMD_FLUSH, "QUIT\r\n");
+
+END_OFF:
+
+#ifndef DISABLE_TLS
+tls_close(sx->cctx.tls_ctx, TLS_SHUTDOWN_NOWAIT);
+sx->cctx.tls_ctx = NULL;
+#endif
+
+/* Close the socket, and return the appropriate value, first setting
+works because the NULL setting is passed back to the calling process, and
+remote_max_parallel is forced to 1 when delivering over an existing connection,
+
+If all went well and continue_more is set, we shouldn't actually get here if
+there are further addresses, as the return above will be taken. However,
+writing RSET might have failed, or there may be other addresses whose hosts are
+specified in the transports, and therefore not visible at top level, in which
+case continue_more won't get set. */
+
+HDEBUG(D_transport|D_acl|D_v) debug_printf_indent("  SMTP(close)>>\n");
+if (sx->send_quit)
+  {
+  shutdown(sx->cctx.sock, SHUT_WR);
+  millisleep(20);
+  testharness_pause_ms(200);
+  if (fcntl(sx->cctx.sock, F_SETFL, O_NONBLOCK) == 0)
+    for (int i = 16; read(sx->cctx.sock, sx->inbuffer, sizeof(sx->inbuffer)) > 0 && i > 0;)
+      i--;				/* drain socket */
+  }
+(void)close(sx->cctx.sock);
+
+#ifndef DISABLE_EVENT
+(void) event_raise(tblock->event_action, US"tcp:close", NULL);
+#endif
+
+#ifdef SUPPORT_DANE
+if (dane_held)
+  {
+  sx->first_addr = NULL;
+  for (address_item * a = sx->addrlist->next; a; a = a->next)
+    if (a->transport_return == DANE)
+      {
+      a->transport_return = PENDING_DEFER;
+      if (!sx->first_addr)
+	{
+	/* Remember the new start-point in the addrlist, for smtp_setup_conn()
+	to get the domain string for SNI */
+
+	sx->first_addr = a;
+	DEBUG(D_transport) debug_printf("DANE: go-around for %s\n", a->domain);
+	}
+      }
+  goto DANE_DOMAINS;
+  }
+#endif
+
+continue_transport = NULL;
+continue_hostname = NULL;
+return yield;
+
+TIDYUP:
+#ifdef SUPPORT_DANE
+if (dane_held) for (address_item * a = sx->addrlist->next; a; a = a->next)
+  if (a->transport_return == DANE)
+    a->transport_return = PENDING_DEFER;
+#endif
+return yield;
+}
+
+
+
+
+/*************************************************
+*              Closedown entry point             *
+*************************************************/
+
+/* This function is called when exim is passed an open smtp channel
+from another incarnation, but the message which it has been asked
+to deliver no longer exists. The channel is on stdin.
+
+We might do fancy things like looking for another message to send down
+the channel, but if the one we sought has gone, it has probably been
+delivered by some other process that itself will seek further messages,
+so just close down our connection.
+
+Argument:   pointer to the transport instance block
+Returns:    nothing
+*/
+
+void
+smtp_transport_closedown(transport_instance *tblock)
+{
+smtp_transport_options_block * ob = SOB tblock->options_block;
+client_conn_ctx cctx;
+smtp_context sx;
+uschar buffer[256];
+uschar inbuffer[4096];
+uschar outbuffer[16];
+
+/*XXX really we need an active-smtp-client ctx, rather than assuming stdout */
+cctx.sock = fileno(stdin);
+cctx.tls_ctx = cctx.sock == tls_out.active.sock ? tls_out.active.tls_ctx : NULL;
+
+sx.inblock.cctx = &cctx;
+sx.inblock.buffer = inbuffer;
+sx.inblock.buffersize = sizeof(inbuffer);
+sx.inblock.ptr = inbuffer;
+sx.inblock.ptrend = inbuffer;
+
+sx.outblock.cctx = &cctx;
+sx.outblock.buffersize = sizeof(outbuffer);
+sx.outblock.buffer = outbuffer;
+sx.outblock.ptr = outbuffer;
+sx.outblock.cmd_count = 0;
+sx.outblock.authenticating = FALSE;
+
+(void)smtp_write_command(&sx, SCMD_FLUSH, "QUIT\r\n");
+(void)smtp_read_response(&sx, buffer, sizeof(buffer), '2', ob->command_timeout);
+(void)close(cctx.sock);
+}
+
+
+
+/*************************************************
+*            Prepare addresses for delivery      *
+*************************************************/
+
+/* This function is called to flush out error settings from previous delivery
+attempts to other hosts. It also records whether we got here via an MX record
+or not in the more_errno field of the address. We are interested only in
+addresses that are still marked DEFER - others may have got delivered to a
+previously considered IP address. Set their status to PENDING_DEFER to indicate
+which ones are relevant this time.
+
+Arguments:
+  addrlist     the list of addresses
+  host         the host we are delivering to
+
+Returns:       the first address for this delivery
+*/
+
+static address_item *
+prepare_addresses(address_item *addrlist, host_item *host)
+{
+address_item *first_addr = NULL;
+for (address_item * addr = addrlist; addr; addr = addr->next)
+  if (addr->transport_return == DEFER)
+    {
+    if (!first_addr) first_addr = addr;
+    addr->transport_return = PENDING_DEFER;
+    addr->basic_errno = 0;
+    addr->more_errno = (host->mx >= 0)? 'M' : 'A';
+    addr->message = NULL;
+#ifndef DISABLE_TLS
+    addr->cipher = NULL;
+    addr->ourcert = NULL;
+    addr->peercert = NULL;
+    addr->peerdn = NULL;
+    addr->ocsp = OCSP_NOT_REQ;
+    addr->tlsver = NULL;
+#endif
+#ifdef EXPERIMENTAL_DSN_INFO
+    addr->smtp_greeting = NULL;
+    addr->helo_response = NULL;
+#endif
+    }
+return first_addr;
+}
+
+
+
+/*************************************************
+*              Main entry point                  *
+*************************************************/
+
+/* See local README for interface details. As this is a remote transport, it is
+given a chain of addresses to be delivered in one connection, if possible. It
+always returns TRUE, indicating that each address has its own independent
+status set, except if there is a setting up problem, in which case it returns
+FALSE. */
+
+BOOL
+smtp_transport_entry(
+  transport_instance *tblock,      /* data for this instantiation */
+  address_item *addrlist)          /* addresses we are working on */
+{
+int defport;
+int hosts_defer = 0;
+int hosts_fail  = 0;
+int hosts_looked_up = 0;
+int hosts_retry = 0;
+int hosts_serial = 0;
+int hosts_total = 0;
+int total_hosts_tried = 0;
+BOOL expired = TRUE;
+uschar *expanded_hosts = NULL;
+uschar *pistring;
+uschar *tid = string_sprintf("%s transport", tblock->name);
+smtp_transport_options_block *ob = SOB tblock->options_block;
+host_item *hostlist = addrlist->host_list;
+host_item *host = NULL;
+
+DEBUG(D_transport)
+  {
+  debug_printf("%s transport entered\n", tblock->name);
+  for (address_item * addr = addrlist; addr; addr = addr->next)
+    debug_printf("  %s\n", addr->address);
+  if (hostlist)
+    {
+    debug_printf("hostlist:\n");
+    for (host_item * host = hostlist; host; host = host->next)
+      debug_printf("  '%s' IP %s port %d\n", host->name, host->address, host->port);
+    }
+  if (continue_hostname)
+    debug_printf("already connected to %s [%s] (on fd %d)\n",
+      continue_hostname, continue_host_address,
+      cutthrough.cctx.sock >= 0 ? cutthrough.cctx.sock : 0);
+  }
+
+/* Set the flag requesting that these hosts be added to the waiting
+database if the delivery fails temporarily or if we are running with
+queue_smtp or a 2-stage queue run. This gets unset for certain
+kinds of error, typically those that are specific to the message. */
+
+update_waiting =  TRUE;
+
+/* If a host list is not defined for the addresses - they must all have the
+same one in order to be passed to a single transport - or if the transport has
+a host list with hosts_override set, use the host list supplied with the
+transport. It is an error for this not to exist. */
+
+if (!hostlist || (ob->hosts_override && ob->hosts))
+  {
+  if (!ob->hosts)
+    {
+    addrlist->message = string_sprintf("%s transport called with no hosts set",
+      tblock->name);
+    addrlist->transport_return = PANIC;
+    return FALSE;   /* Only top address has status */
+    }
+
+  DEBUG(D_transport) debug_printf("using the transport's hosts: %s\n",
+    ob->hosts);
+
+  /* If the transport's host list contains no '$' characters, and we are not
+  randomizing, it is fixed and therefore a chain of hosts can be built once
+  and for all, and remembered for subsequent use by other calls to this
+  transport. If, on the other hand, the host list does contain '$', or we are
+  randomizing its order, we have to rebuild it each time. In the fixed case,
+  as the hosts string will never be used again, it doesn't matter that we
+  replace all the : characters with zeros. */
+
+  if (!ob->hostlist)
+    {
+    uschar *s = ob->hosts;
+
+    if (Ustrchr(s, '$') != NULL)
+      {
+      if (!(expanded_hosts = expand_string(s)))
+        {
+        addrlist->message = string_sprintf("failed to expand list of hosts "
+          "\"%s\" in %s transport: %s", s, tblock->name, expand_string_message);
+        addrlist->transport_return = f.search_find_defer ? DEFER : PANIC;
+        return FALSE;     /* Only top address has status */
+        }
+      DEBUG(D_transport) debug_printf("expanded list of hosts \"%s\" to "
+        "\"%s\"\n", s, expanded_hosts);
+      s = expanded_hosts;
+      }
+    else
+      if (ob->hosts_randomize) s = expanded_hosts = string_copy(s);
+
+    if (is_tainted(s))
+      {
+      log_write(0, LOG_MAIN|LOG_PANIC,
+	"attempt to use tainted host list '%s' from '%s' in transport %s",
+	s, ob->hosts, tblock->name);
+      /* Avoid leaking info to an attacker */
+      addrlist->message = US"internal configuration error";
+      addrlist->transport_return = PANIC;
+      return FALSE;
+      }
+
+    host_build_hostlist(&hostlist, s, ob->hosts_randomize);
+
+    /* Check that the expansion yielded something useful. */
+    if (!hostlist)
+      {
+      addrlist->message =
+        string_sprintf("%s transport has empty hosts setting", tblock->name);
+      addrlist->transport_return = PANIC;
+      return FALSE;   /* Only top address has status */
+      }
+
+    /* If there was no expansion of hosts, save the host list for
+    next time. */
+
+    if (!expanded_hosts) ob->hostlist = hostlist;
+    }
+
+  /* This is not the first time this transport has been run in this delivery;
+  the host list was built previously. */
+
+  else
+    hostlist = ob->hostlist;
+  }
+
+/* The host list was supplied with the address. If hosts_randomize is set, we
+must sort it into a random order if it did not come from MX records and has not
+already been randomized (but don't bother if continuing down an existing
+connection). */
+
+else if (ob->hosts_randomize && hostlist->mx == MX_NONE && !continue_hostname)
+  {
+  host_item *newlist = NULL;
+  while (hostlist)
+    {
+    host_item *h = hostlist;
+    hostlist = hostlist->next;
+
+    h->sort_key = random_number(100);
+
+    if (!newlist)
+      {
+      h->next = NULL;
+      newlist = h;
+      }
+    else if (h->sort_key < newlist->sort_key)
+      {
+      h->next = newlist;
+      newlist = h;
+      }
+    else
+      {
+      host_item *hh = newlist;
+      while (hh->next)
+        {
+        if (h->sort_key < hh->next->sort_key) break;
+        hh = hh->next;
+        }
+      h->next = hh->next;
+      hh->next = h;
+      }
+    }
+
+  hostlist = addrlist->host_list = newlist;
+  }
+
+/* Sort out the default port.  */
+
+if (!smtp_get_port(ob->port, addrlist, &defport, tid)) return FALSE;
+
+/* For each host-plus-IP-address on the list:
+
+.  If this is a continued delivery and the host isn't the one with the
+   current connection, skip.
+
+.  If the status is unusable (i.e. previously failed or retry checked), skip.
+
+.  If no IP address set, get the address, either by turning the name into
+   an address, calling gethostbyname if gethostbyname is on, or by calling
+   the DNS. The DNS may yield multiple addresses, in which case insert the
+   extra ones into the list.
+
+.  Get the retry data if not previously obtained for this address and set the
+   field which remembers the state of this address. Skip if the retry time is
+   not reached. If not, remember whether retry data was found. The retry string
+   contains both the name and the IP address.
+
+.  Scan the list of addresses and mark those whose status is DEFER as
+   PENDING_DEFER. These are the only ones that will be processed in this cycle
+   of the hosts loop.
+
+.  Make a delivery attempt - addresses marked PENDING_DEFER will be tried.
+   Some addresses may be successfully delivered, others may fail, and yet
+   others may get temporary errors and so get marked DEFER.
+
+.  The return from the delivery attempt is OK if a connection was made and a
+   valid SMTP dialogue was completed. Otherwise it is DEFER.
+
+.  If OK, add a "remove" retry item for this host/IPaddress, if any.
+
+.  If fail to connect, or other defer state, add a retry item.
+
+.  If there are any addresses whose status is still DEFER, carry on to the
+   next host/IPaddress, unless we have tried the number of hosts given
+   by hosts_max_try or hosts_max_try_hardlimit; otherwise return. Note that
+   there is some fancy logic for hosts_max_try that means its limit can be
+   overstepped in some circumstances.
+
+If we get to the end of the list, all hosts have deferred at least one address,
+or not reached their retry times. If delay_after_cutoff is unset, it requests a
+delivery attempt to those hosts whose last try was before the arrival time of
+the current message. To cope with this, we have to go round the loop a second
+time. After that, set the status and error data for any addresses that haven't
+had it set already. */
+
+for (int cutoff_retry = 0;
+     expired && cutoff_retry < (ob->delay_after_cutoff ? 1 : 2);
+     cutoff_retry++)
+  {
+  host_item *nexthost = NULL;
+  int unexpired_hosts_tried = 0;
+  BOOL continue_host_tried = FALSE;
+
+retry_non_continued:
+  for (host = hostlist;
+          host
+       && unexpired_hosts_tried < ob->hosts_max_try
+       && total_hosts_tried < ob->hosts_max_try_hardlimit;
+       host = nexthost)
+    {
+    int rc;
+    int host_af;
+    BOOL host_is_expired = FALSE;
+    BOOL message_defer = FALSE;
+    BOOL some_deferred = FALSE;
+    address_item *first_addr = NULL;
+    uschar *interface = NULL;
+    uschar *retry_host_key = NULL;
+    uschar *retry_message_key = NULL;
+    uschar *serialize_key = NULL;
+
+    /* Default next host is next host. :-) But this can vary if the
+    hosts_max_try limit is hit (see below). It may also be reset if a host
+    address is looked up here (in case the host was multihomed). */
+
+    nexthost = host->next;
+
+    /* If the address hasn't yet been obtained from the host name, look it up
+    now, unless the host is already marked as unusable. If it is marked as
+    unusable, it means that the router was unable to find its IP address (in
+    the DNS or wherever) OR we are in the 2nd time round the cutoff loop, and
+    the lookup failed last time. We don't get this far if *all* MX records
+    point to non-existent hosts; that is treated as a hard error.
+
+    We can just skip this host entirely. When the hosts came from the router,
+    the address will timeout based on the other host(s); when the address is
+    looked up below, there is an explicit retry record added.
+
+    Note that we mustn't skip unusable hosts if the address is not unset; they
+    may be needed as expired hosts on the 2nd time round the cutoff loop. */
+
+    if (!host->address)
+      {
+      int new_port, flags;
+
+      if (host->status >= hstatus_unusable)
+        {
+        DEBUG(D_transport) debug_printf("%s has no address and is unusable - skipping\n",
+          host->name);
+        continue;
+        }
+
+      DEBUG(D_transport) debug_printf("getting address for %s\n", host->name);
+
+      /* The host name is permitted to have an attached port. Find it, and
+      strip it from the name. Just remember it for now. */
+
+      new_port = host_item_get_port(host);
+
+      /* Count hosts looked up */
+
+      hosts_looked_up++;
+
+      /* Find by name if so configured, or if it's an IP address. We don't
+      just copy the IP address, because we need the test-for-local to happen. */
+
+      flags = HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
+      if (ob->dns_qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
+      if (ob->dns_search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
+
+      if (ob->gethostbyname || string_is_ip_address(host->name, NULL) != 0)
+        rc = host_find_byname(host, NULL, flags, NULL, TRUE);
+      else
+        rc = host_find_bydns(host, NULL, flags, NULL, NULL, NULL,
+	  &ob->dnssec,		/* domains for request/require */
+          NULL, NULL);
+
+      /* Update the host (and any additional blocks, resulting from
+      multihoming) with a host-specific port, if any. */
+
+      for (host_item * hh = host; hh != nexthost; hh = hh->next) hh->port = new_port;
+
+      /* Failure to find the host at this time (usually DNS temporary failure)
+      is really a kind of routing failure rather than a transport failure.
+      Therefore we add a retry item of the routing kind, not to stop us trying
+      to look this name up here again, but to ensure the address gets timed
+      out if the failures go on long enough. A complete failure at this point
+      commonly points to a configuration error, but the best action is still
+      to carry on for the next host. */
+
+      if (rc == HOST_FIND_AGAIN || rc == HOST_FIND_SECURITY || rc == HOST_FIND_FAILED)
+        {
+        retry_add_item(addrlist, string_sprintf("R:%s", host->name), 0);
+        expired = FALSE;
+        if (rc == HOST_FIND_AGAIN) hosts_defer++; else hosts_fail++;
+        DEBUG(D_transport) debug_printf("rc = %s for %s\n", (rc == HOST_FIND_AGAIN)?
+          "HOST_FIND_AGAIN" : "HOST_FIND_FAILED", host->name);
+        host->status = hstatus_unusable;
+
+        for (address_item * addr = addrlist; addr; addr = addr->next)
+          {
+          if (addr->transport_return != DEFER) continue;
+          addr->basic_errno = ERRNO_UNKNOWNHOST;
+          addr->message = string_sprintf(
+	    rc == HOST_FIND_SECURITY
+	      ? "lookup of IP address for %s was insecure"
+	      : "failed to lookup IP address for %s",
+	    host->name);
+          }
+        continue;
+        }
+
+      /* If the host is actually the local host, we may have a problem, or
+      there may be some cunning configuration going on. In the problem case,
+      log things and give up. The default transport status is already DEFER. */
+
+      if (rc == HOST_FOUND_LOCAL && !ob->allow_localhost)
+        {
+        for (address_item * addr = addrlist; addr; addr = addr->next)
+          {
+          addr->basic_errno = ERRNO_HOST_IS_LOCAL;
+          addr->message = string_sprintf("%s transport found host %s to be "
+            "local", tblock->name, host->name);
+          }
+        goto END_TRANSPORT;
+        }
+      }   /* End of block for IP address lookup */
+
+    /* If this is a continued delivery, we are interested only in the host
+    which matches the name of the existing open channel. The check is put
+    here after the local host lookup, in case the name gets expanded as a
+    result of the lookup. Set expired FALSE, to save the outer loop executing
+    twice. */
+
+    if (continue_hostname)
+      if (  Ustrcmp(continue_hostname, host->name) != 0
+         || Ustrcmp(continue_host_address, host->address) != 0
+	 )
+	{
+	expired = FALSE;
+	continue;      /* With next host */
+	}
+      else
+	continue_host_tried = TRUE;
+
+    /* Reset the default next host in case a multihomed host whose addresses
+    are not looked up till just above added to the host list. */
+
+    nexthost = host->next;
+
+    /* If queue_smtp is set (-odqs or the first part of a 2-stage run), or the
+    domain is in queue_smtp_domains, we don't actually want to attempt any
+    deliveries. When doing a queue run, queue_smtp_domains is always unset. If
+    there is a lookup defer in queue_smtp_domains, proceed as if the domain
+    were not in it. We don't want to hold up all SMTP deliveries! Except when
+    doing a two-stage queue run, don't do this if forcing. */
+
+    if (  (!f.deliver_force || f.queue_2stage)
+       && (  f.queue_smtp
+	  || match_isinlist(addrlist->domain,
+	      CUSS &queue_smtp_domains, 0,
+	      &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
+       )
+      {
+      DEBUG(D_transport) debug_printf("first-pass routing only\n");
+      expired = FALSE;
+      for (address_item * addr = addrlist; addr; addr = addr->next)
+        if (addr->transport_return == DEFER)
+	  addr->message = US"first-pass only routing due to -odqs, "
+			    "queue_smtp_domains or control=queue";
+      continue;      /* With next host */
+      }
+
+    /* Count hosts being considered - purely for an intelligent comment
+    if none are usable. */
+
+    hosts_total++;
+
+    /* Set $host and $host address now in case they are needed for the
+    interface expansion or the serialize_hosts check; they remain set if an
+    actual delivery happens. */
+
+    deliver_host = host->name;
+    deliver_host_address = host->address;
+    lookup_dnssec_authenticated = host->dnssec == DS_YES ? US"yes"
+				: host->dnssec == DS_NO ? US"no"
+				: US"";
+
+    /* Set up a string for adding to the retry key if the port number is not
+    the standard SMTP port. A host may have its own port setting that overrides
+    the default. */
+
+    pistring = string_sprintf(":%d", host->port == PORT_NONE
+      ? defport : host->port);
+    if (Ustrcmp(pistring, ":25") == 0) pistring = US"";
+
+    /* Select IPv4 or IPv6, and choose an outgoing interface. If the interface
+    string is set, even if constant (as different transports can have different
+    constant settings), we must add it to the key that is used for retries,
+    because connections to the same host from a different interface should be
+    treated separately. */
+
+    host_af = Ustrchr(host->address, ':') == NULL ? AF_INET : AF_INET6;
+      {
+      uschar * s = ob->interface;
+      if (s && *s)
+	{
+	if (!smtp_get_interface(s, host_af, addrlist, &interface, tid))
+	  return FALSE;
+	pistring = string_sprintf("%s/%s", pistring, interface);
+	}
+      }
+
+    /* The first time round the outer loop, check the status of the host by
+    inspecting the retry data. The second time round, we are interested only
+    in expired hosts that haven't been tried since this message arrived. */
+
+    if (cutoff_retry == 0)
+      {
+      BOOL incl_ip;
+      /* Ensure the status of the address is set by checking retry data if
+      necessary. There may be host-specific retry data (applicable to all
+      messages) and also data for retries of a specific message at this host.
+      If either of these retry records are actually read, the keys used are
+      returned to save recomputing them later. */
+
+      if (exp_bool(addrlist, US"transport", tblock->name, D_transport,
+		US"retry_include_ip_address", ob->retry_include_ip_address,
+		ob->expand_retry_include_ip_address, &incl_ip) != OK)
+	continue;	/* with next host */
+
+      host_is_expired = retry_check_address(addrlist->domain, host, pistring,
+        incl_ip, &retry_host_key, &retry_message_key);
+
+      DEBUG(D_transport) debug_printf("%s [%s]%s retry-status = %s\n", host->name,
+        host->address ? host->address : US"", pistring,
+        host->status == hstatus_usable ? "usable"
+        : host->status == hstatus_unusable ? "unusable"
+        : host->status == hstatus_unusable_expired ? "unusable (expired)" : "?");
+
+      /* Skip this address if not usable at this time, noting if it wasn't
+      actually expired, both locally and in the address. */
+
+      switch (host->status)
+        {
+        case hstatus_unusable:
+	  expired = FALSE;
+	  setflag(addrlist, af_retry_skipped);
+	  /* Fall through */
+
+        case hstatus_unusable_expired:
+	  switch (host->why)
+	    {
+	    case hwhy_retry: hosts_retry++; break;
+	    case hwhy_failed:  hosts_fail++; break;
+	    case hwhy_insecure:
+	    case hwhy_deferred: hosts_defer++; break;
+	    }
+
+	  /* If there was a retry message key, implying that previously there
+	  was a message-specific defer, we don't want to update the list of
+	  messages waiting for these hosts. */
+
+	  if (retry_message_key) update_waiting = FALSE;
+	  continue;   /* With the next host or IP address */
+        }
+      }
+
+    /* Second time round the loop: if the address is set but expired, and
+    the message is newer than the last try, let it through. */
+
+    else
+      {
+      if (  !host->address
+         || host->status != hstatus_unusable_expired
+	 || host->last_try > received_time.tv_sec)
+        continue;
+      DEBUG(D_transport) debug_printf("trying expired host %s [%s]%s\n",
+          host->name, host->address, pistring);
+      host_is_expired = TRUE;
+      }
+
+    /* Setting "expired=FALSE" doesn't actually mean not all hosts are expired;
+    it remains TRUE only if all hosts are expired and none are actually tried.
+    */
+
+    expired = FALSE;
+
+    /* If this host is listed as one to which access must be serialized,
+    see if another Exim process has a connection to it, and if so, skip
+    this host. If not, update the database to record our connection to it
+    and remember this for later deletion. Do not do any of this if we are
+    sending the message down a pre-existing connection. */
+
+    if (  !continue_hostname
+       && verify_check_given_host(CUSS &ob->serialize_hosts, host) == OK)
+      {
+      serialize_key = string_sprintf("host-serialize-%s", host->name);
+      if (!enq_start(serialize_key, 1))
+        {
+        DEBUG(D_transport)
+          debug_printf("skipping host %s because another Exim process "
+            "is connected to it\n", host->name);
+        hosts_serial++;
+        continue;
+        }
+      }
+
+    /* OK, we have an IP address that is not waiting for its retry time to
+    arrive (it might be expired) OR (second time round the loop) we have an
+    expired host that hasn't been tried since the message arrived. Have a go
+    at delivering the message to it. First prepare the addresses by flushing
+    out the result of previous attempts, and finding the first address that
+    is still to be delivered. */
+
+    first_addr = prepare_addresses(addrlist, host);
+
+    DEBUG(D_transport) debug_printf("delivering %s to %s [%s] (%s%s)\n",
+      message_id, host->name, host->address, addrlist->address,
+      addrlist->next ? ", ..." : "");
+
+    set_process_info("delivering %s to %s [%s]%s (%s%s)",
+      message_id, host->name, host->address, pistring, addrlist->address,
+      addrlist->next ? ", ..." : "");
+
+    /* This is not for real; don't do the delivery. If there are
+    any remaining hosts, list them. */
+
+    if (f.dont_deliver)
+      {
+      struct timeval now;
+      gettimeofday(&now, NULL);
+      set_errno_nohost(addrlist, 0, NULL, OK, FALSE, &now);
+      for (address_item * addr = addrlist; addr; addr = addr->next)
+        {
+        addr->host_used = host;
+        addr->special_action = '*';
+        addr->message = US"delivery bypassed by -N option";
+        }
+      DEBUG(D_transport)
+        {
+        debug_printf("*** delivery by %s transport bypassed by -N option\n"
+                     "*** host and remaining hosts:\n", tblock->name);
+        for (host_item * host2 = host; host2; host2 = host2->next)
+          debug_printf("    %s [%s]\n", host2->name,
+            host2->address ? host2->address : US"unset");
+        }
+      rc = OK;
+      }
+
+    /* This is for real. If the host is expired, we don't count it for
+    hosts_max_retry. This ensures that all hosts must expire before an address
+    is timed out, unless hosts_max_try_hardlimit (which protects against
+    lunatic DNS configurations) is reached.
+
+    If the host is not expired and we are about to hit the hosts_max_retry
+    limit, check to see if there is a subsequent hosts with a different MX
+    value. If so, make that the next host, and don't count this one. This is a
+    heuristic to make sure that different MXs do get tried. With a normal kind
+    of retry rule, they would get tried anyway when the earlier hosts were
+    delayed, but if the domain has a "retry every time" type of rule - as is
+    often used for the the very large ISPs, that won't happen. */
+
+    else
+      {
+      host_item * thost;
+      /* Make a copy of the host if it is local to this invocation
+       of the transport. */
+
+      if (expanded_hosts)
+	{
+	thost = store_get(sizeof(host_item), FALSE);
+	*thost = *host;
+	thost->name = string_copy(host->name);
+	thost->address = string_copy(host->address);
+	}
+      else
+        thost = host;
+
+      if (!host_is_expired && ++unexpired_hosts_tried >= ob->hosts_max_try)
+        {
+        DEBUG(D_transport)
+          debug_printf("hosts_max_try limit reached with this host\n");
+        for (host_item * h = host; h; h = h->next) if (h->mx != host->mx)
+	  {
+	  nexthost = h;
+	  unexpired_hosts_tried--;
+	  DEBUG(D_transport) debug_printf("however, a higher MX host exists "
+	    "and will be tried\n");
+	  break;
+	  }
+        }
+
+      /* Attempt the delivery. */
+
+      total_hosts_tried++;
+      rc = smtp_deliver(addrlist, thost, host_af, defport, interface, tblock,
+        &message_defer, FALSE);
+
+      /* Yield is one of:
+         OK     => connection made, each address contains its result;
+                     message_defer is set for message-specific defers (when all
+                     recipients are marked defer)
+         DEFER  => there was a non-message-specific delivery problem;
+         ERROR  => there was a problem setting up the arguments for a filter,
+                   or there was a problem with expanding added headers
+      */
+
+      /* If the result is not OK, there was a non-message-specific problem.
+      If the result is DEFER, we need to write to the logs saying what happened
+      for this particular host, except in the case of authentication and TLS
+      failures, where the log has already been written. If all hosts defer a
+      general message is written at the end. */
+
+      if (rc == DEFER && first_addr->basic_errno != ERRNO_AUTHFAIL
+		      && first_addr->basic_errno != ERRNO_TLSFAILURE)
+        write_logs(host, first_addr->message, first_addr->basic_errno);
+
+#ifndef DISABLE_EVENT
+      if (rc == DEFER)
+	deferred_event_raise(first_addr, host, US"msg:host:defer");
+#endif
+
+      /* If STARTTLS was accepted, but there was a failure in setting up the
+      TLS session (usually a certificate screwup), and the host is not in
+      hosts_require_tls, and tls_tempfail_tryclear is true, try again, with
+      TLS forcibly turned off. We have to start from scratch with a new SMTP
+      connection. That's why the retry is done from here, not from within
+      smtp_deliver(). [Rejections of STARTTLS itself don't screw up the
+      session, so the in-clear transmission after those errors, if permitted,
+      happens inside smtp_deliver().] */
+
+#ifndef DISABLE_TLS
+      if (  rc == DEFER
+	 && first_addr->basic_errno == ERRNO_TLSFAILURE
+	 && ob->tls_tempfail_tryclear
+	 && verify_check_given_host(CUSS &ob->hosts_require_tls, host) != OK
+	 )
+        {
+        log_write(0, LOG_MAIN,
+	  "%s: delivering unencrypted to H=%s [%s] (not in hosts_require_tls)",
+	  first_addr->message, host->name, host->address);
+        first_addr = prepare_addresses(addrlist, host);
+        rc = smtp_deliver(addrlist, thost, host_af, defport, interface, tblock,
+          &message_defer, TRUE);
+        if (rc == DEFER && first_addr->basic_errno != ERRNO_AUTHFAIL)
+          write_logs(host, first_addr->message, first_addr->basic_errno);
+# ifndef DISABLE_EVENT
+	if (rc == DEFER)
+	  deferred_event_raise(first_addr, host, US"msg:host:defer");
+# endif
+        }
+#endif	/*DISABLE_TLS*/
+
+#ifndef DISABLE_EVENT
+      /* If the last host gave a defer raise a per-message event */
+
+      if (  !(  nexthost
+	     && unexpired_hosts_tried < ob->hosts_max_try
+	     && total_hosts_tried < ob->hosts_max_try_hardlimit
+	     )
+         && (message_defer || rc == DEFER)
+	 )
+	deferred_event_raise(first_addr, host, US"msg:defer");
+#endif
+      }
+
+    /* Delivery attempt finished */
+
+    set_process_info("delivering %s: just tried %s [%s]%s for %s%s: result %s",
+      message_id, host->name, host->address, pistring, addrlist->address,
+      addrlist->next ? " (& others)" : "", rc_to_string(rc));
+
+    /* Release serialization if set up */
+
+    if (serialize_key) enq_end(serialize_key);
+
+    /* If the result is DEFER, or if a host retry record is known to exist, we
+    need to add an item to the retry chain for updating the retry database
+    at the end of delivery. We only need to add the item to the top address,
+    of course. Also, if DEFER, we mark the IP address unusable so as to skip it
+    for any other delivery attempts using the same address. (It is copied into
+    the unusable tree at the outer level, so even if different address blocks
+    contain the same address, it still won't get tried again.) */
+
+    if (rc == DEFER || retry_host_key)
+      {
+      int delete_flag = rc != DEFER ? rf_delete : 0;
+      if (!retry_host_key)
+        {
+	BOOL incl_ip;
+	if (exp_bool(addrlist, US"transport", tblock->name, D_transport,
+		  US"retry_include_ip_address", ob->retry_include_ip_address,
+		  ob->expand_retry_include_ip_address, &incl_ip) != OK)
+	  incl_ip = TRUE;	/* error; use most-specific retry record */
+
+        retry_host_key = incl_ip
+	  ? string_sprintf("T:%S:%s%s", host->name, host->address, pistring)
+	  : string_sprintf("T:%S%s", host->name, pistring);
+        }
+
+      /* If a delivery of another message over an existing SMTP connection
+      yields DEFER, we do NOT set up retry data for the host. This covers the
+      case when there are delays in routing the addresses in the second message
+      that are so long that the server times out. This is alleviated by not
+      routing addresses that previously had routing defers when handling an
+      existing connection, but even so, this case may occur (e.g. if a
+      previously happily routed address starts giving routing defers). If the
+      host is genuinely down, another non-continued message delivery will
+      notice it soon enough. */
+
+      if (delete_flag != 0 || !continue_hostname)
+        retry_add_item(first_addr, retry_host_key, rf_host | delete_flag);
+
+      /* We may have tried an expired host, if its retry time has come; ensure
+      the status reflects the expiry for the benefit of any other addresses. */
+
+      if (rc == DEFER)
+        {
+        host->status = host_is_expired
+	  ? hstatus_unusable_expired : hstatus_unusable;
+        host->why = hwhy_deferred;
+        }
+      }
+
+    /* If message_defer is set (host was OK, but every recipient got deferred
+    because of some message-specific problem), or if that had happened
+    previously so that a message retry key exists, add an appropriate item
+    to the retry chain. Note that if there was a message defer but now there is
+    a host defer, the message defer record gets deleted. That seems perfectly
+    reasonable. Also, stop the message from being remembered as waiting
+    for specific hosts. */
+
+    if (message_defer || retry_message_key)
+      {
+      int delete_flag = message_defer ? 0 : rf_delete;
+      if (!retry_message_key)
+        {
+	BOOL incl_ip;
+	if (exp_bool(addrlist, US"transport", tblock->name, D_transport,
+		  US"retry_include_ip_address", ob->retry_include_ip_address,
+		  ob->expand_retry_include_ip_address, &incl_ip) != OK)
+	  incl_ip = TRUE;	/* error; use most-specific retry record */
+
+        retry_message_key = incl_ip
+	  ? string_sprintf("T:%S:%s%s:%s", host->name, host->address, pistring,
+	      message_id)
+	  : string_sprintf("T:%S%s:%s", host->name, pistring, message_id);
+        }
+      retry_add_item(addrlist, retry_message_key,
+        rf_message | rf_host | delete_flag);
+      update_waiting = FALSE;
+      }
+
+    /* Any return other than DEFER (that is, OK or ERROR) means that the
+    addresses have got their final statuses filled in for this host. In the OK
+    case, see if any of them are deferred. */
+
+    if (rc == OK)
+      for (address_item * addr = addrlist; addr; addr = addr->next)
+        if (addr->transport_return == DEFER)
+          {
+          some_deferred = TRUE;
+          break;
+          }
+
+    /* If no addresses deferred or the result was ERROR, return. We do this for
+    ERROR because a failing filter set-up or add_headers expansion is likely to
+    fail for any host we try. */
+
+    if (rc == ERROR || (rc == OK && !some_deferred))
+      {
+      DEBUG(D_transport) debug_printf("Leaving %s transport\n", tblock->name);
+      return TRUE;    /* Each address has its status */
+      }
+
+    /* If the result was DEFER or some individual addresses deferred, let
+    the loop run to try other hosts with the deferred addresses, except for the
+    case when we were trying to deliver down an existing channel and failed.
+    Don't try any other hosts in this case. */
+
+    if (continue_hostname) break;
+
+    /* If the whole delivery, or some individual addresses, were deferred and
+    there are more hosts that could be tried, do not count this host towards
+    the hosts_max_try limit if the age of the message is greater than the
+    maximum retry time for this host. This means we may try try all hosts,
+    ignoring the limit, when messages have been around for some time. This is
+    important because if we don't try all hosts, the address will never time
+    out. NOTE: this does not apply to hosts_max_try_hardlimit. */
+
+    if ((rc == DEFER || some_deferred) && nexthost)
+      {
+      BOOL timedout;
+      retry_config *retry = retry_find_config(host->name, NULL, 0, 0);
+
+      if (retry && retry->rules)
+        {
+        retry_rule *last_rule;
+        for (last_rule = retry->rules;
+             last_rule->next;
+             last_rule = last_rule->next);
+        timedout = time(NULL) - received_time.tv_sec > last_rule->timeout;
+        }
+      else timedout = TRUE;    /* No rule => timed out */
+
+      if (timedout)
+        {
+        unexpired_hosts_tried--;
+        DEBUG(D_transport) debug_printf("temporary delivery error(s) override "
+          "hosts_max_try (message older than host's retry time)\n");
+        }
+      }
+
+    DEBUG(D_transport)
+      {
+      if (unexpired_hosts_tried >= ob->hosts_max_try)
+	debug_printf("reached transport hosts_max_try limit %d\n",
+	  ob->hosts_max_try);
+      if (total_hosts_tried >= ob->hosts_max_try_hardlimit)
+	debug_printf("reached transport hosts_max_try_hardlimit limit %d\n",
+	  ob->hosts_max_try_hardlimit);
+      }
+
+    testharness_pause_ms(500); /* let server debug out */
+    }   /* End of loop for trying multiple hosts. */
+
+  /* If we failed to find a matching host in the list, for an already-open
+  connection, just close it and start over with the list.  This can happen
+  for routing that changes from run to run, or big multi-IP sites with
+  round-robin DNS. */
+
+  if (continue_hostname && !continue_host_tried)
+    {
+    int fd = cutthrough.cctx.sock >= 0 ? cutthrough.cctx.sock : 0;
+
+    DEBUG(D_transport) debug_printf("no hosts match already-open connection\n");
+#ifndef DISABLE_TLS
+    /* A TLS conn could be open for a cutthrough, but not for a plain continued-
+    transport */
+/*XXX doublecheck that! */
+
+    if (cutthrough.cctx.sock >= 0 && cutthrough.is_tls)
+      {
+      (void) tls_write(cutthrough.cctx.tls_ctx, US"QUIT\r\n", 6, FALSE);
+      tls_close(cutthrough.cctx.tls_ctx, TLS_SHUTDOWN_NOWAIT);
+      cutthrough.cctx.tls_ctx = NULL;
+      cutthrough.is_tls = FALSE;
+      }
+    else
+#else
+      (void) write(fd, US"QUIT\r\n", 6);
+#endif
+    (void) close(fd);
+    cutthrough.cctx.sock = -1;
+    continue_hostname = NULL;
+    goto retry_non_continued;
+    }
+
+  /* This is the end of the loop that repeats iff expired is TRUE and
+  ob->delay_after_cutoff is FALSE. The second time round we will
+  try those hosts that haven't been tried since the message arrived. */
+
+  DEBUG(D_transport)
+    {
+    debug_printf("all IP addresses skipped or deferred at least one address\n");
+    if (expired && !ob->delay_after_cutoff && cutoff_retry == 0)
+      debug_printf("retrying IP addresses not tried since message arrived\n");
+    }
+  }
+
+
+/* Get here if all IP addresses are skipped or defer at least one address. In
+MUA wrapper mode, this will happen only for connection or other non-message-
+specific failures. Force the delivery status for all addresses to FAIL. */
+
+if (mua_wrapper)
+  {
+  for (address_item * addr = addrlist; addr; addr = addr->next)
+    addr->transport_return = FAIL;
+  goto END_TRANSPORT;
+  }
+
+/* In the normal, non-wrapper case, add a standard message to each deferred
+address if there hasn't been an error, that is, if it hasn't actually been
+tried this time. The variable "expired" will be FALSE if any deliveries were
+actually tried, or if there was at least one host that was not expired. That
+is, it is TRUE only if no deliveries were tried and all hosts were expired. If
+a delivery has been tried, an error code will be set, and the failing of the
+message is handled by the retry code later.
+
+If queue_smtp is set, or this transport was called to send a subsequent message
+down an existing TCP/IP connection, and something caused the host not to be
+found, we end up here, but can detect these cases and handle them specially. */
+
+for (address_item * addr = addrlist; addr; addr = addr->next)
+  {
+  /* If host is not NULL, it means that we stopped processing the host list
+  because of hosts_max_try or hosts_max_try_hardlimit. In the former case, this
+  means we need to behave as if some hosts were skipped because their retry
+  time had not come. Specifically, this prevents the address from timing out.
+  However, if we have hit hosts_max_try_hardlimit, we want to behave as if all
+  hosts were tried. */
+
+  if (host)
+    if (total_hosts_tried >= ob->hosts_max_try_hardlimit)
+      {
+      DEBUG(D_transport)
+        debug_printf("hosts_max_try_hardlimit reached: behave as if all "
+          "hosts were tried\n");
+      }
+    else
+      {
+      DEBUG(D_transport)
+        debug_printf("hosts_max_try limit caused some hosts to be skipped\n");
+      setflag(addr, af_retry_skipped);
+      }
+
+  if (f.queue_smtp)    /* no deliveries attempted */
+    {
+    addr->transport_return = DEFER;
+    addr->basic_errno = 0;
+    addr->message = US"SMTP delivery explicitly queued";
+    }
+
+  else if (  addr->transport_return == DEFER
+	  && (addr->basic_errno == ERRNO_UNKNOWNERROR || addr->basic_errno == 0)
+	  && !addr->message
+	  )
+    {
+    addr->basic_errno = ERRNO_HRETRY;
+    if (continue_hostname)
+      addr->message = US"no host found for existing SMTP connection";
+    else if (expired)
+      {
+      setflag(addr, af_pass_message);   /* This is not a security risk */
+      addr->message = string_sprintf(
+	"all hosts%s have been failing for a long time %s",
+	addr->domain ? string_sprintf(" for '%s'", addr->domain) : US"",
+        ob->delay_after_cutoff
+	? US"(and retry time not reached)"
+	: US"and were last tried after this message arrived");
+
+      /* If we are already using fallback hosts, or there are no fallback hosts
+      defined, convert the result to FAIL to cause a bounce. */
+
+      if (addr->host_list == addr->fallback_hosts || !addr->fallback_hosts)
+        addr->transport_return = FAIL;
+      }
+    else
+      {
+      const char * s;
+      if (hosts_retry == hosts_total)
+        s = "retry time not reached for any host%s";
+      else if (hosts_fail == hosts_total)
+        s = "all host address lookups%s failed permanently";
+      else if (hosts_defer == hosts_total)
+        s = "all host address lookups%s failed temporarily";
+      else if (hosts_serial == hosts_total)
+        s = "connection limit reached for all hosts%s";
+      else if (hosts_fail+hosts_defer == hosts_total)
+        s = "all host address lookups%s failed";
+      else
+        s = "some host address lookups failed and retry time "
+        "not reached for other hosts or connection limit reached%s";
+
+      addr->message = string_sprintf(s,
+	addr->domain ? string_sprintf(" for '%s'", addr->domain) : US"");
+      }
+    }
+  }
+
+/* Update the database which keeps information about which messages are waiting
+for which hosts to become available. For some message-specific errors, the
+update_waiting flag is turned off because we don't want follow-on deliveries in
+those cases.  If this transport instance is explicitly limited to one message
+per connection then follow-on deliveries are not possible and there's no need
+to create/update the per-transport wait-<transport_name> database. */
+
+if (update_waiting && tblock->connection_max_messages != 1)
+  transport_update_waiting(hostlist, tblock->name);
+
+END_TRANSPORT:
+
+DEBUG(D_transport) debug_printf("Leaving %s transport\n", tblock->name);
+
+return TRUE;   /* Each address has its status */
+}
+
+#endif	/*!MACRO_PREDEF*/
+/* vi: aw ai sw=2
+*/
+/* End of transport/smtp.c */
diff --git a/src/transports/smtp.h b/src/transports/smtp.h
new file mode 100644
index 0000000..213bca1
--- /dev/null
+++ b/src/transports/smtp.h
@@ -0,0 +1,209 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+/* Copyright (c) University of Cambridge 1995 - 2018 */
+/* Copyright (c) The Exim Maintainers 2020 */
+/* See the file NOTICE for conditions of use and distribution. */
+
+#define DELIVER_BUFFER_SIZE 4096
+
+#define PENDING          256
+#define PENDING_DEFER   (PENDING + DEFER)
+#define PENDING_OK      (PENDING + OK)
+
+
+/* Private structure for the private options and other private data. */
+
+typedef struct {
+  uschar *hosts;
+  uschar *fallback_hosts;
+  host_item *hostlist;
+  host_item *fallback_hostlist;
+  uschar *authenticated_sender;
+  uschar *helo_data;
+  uschar *interface;
+  uschar *port;
+  uschar *protocol;
+  uschar *dscp;
+  uschar *serialize_hosts;
+  uschar *hosts_try_auth;
+  uschar *hosts_require_auth;
+  uschar *hosts_try_chunking;
+#ifdef SUPPORT_DANE
+  uschar *hosts_try_dane;
+  uschar *hosts_require_dane;
+  uschar *dane_require_tls_ciphers;
+#endif
+  uschar *hosts_try_fastopen;
+#ifndef DISABLE_PRDR
+  uschar *hosts_try_prdr;
+#endif
+#ifndef DISABLE_OCSP
+  uschar *hosts_request_ocsp;
+  uschar *hosts_require_ocsp;
+#endif
+  uschar *hosts_require_tls;
+  uschar *hosts_avoid_tls;
+  uschar *hosts_verify_avoid_tls;
+  uschar *hosts_avoid_pipelining;
+#ifndef DISABLE_PIPE_CONNECT
+  uschar *hosts_pipe_connect;
+#endif
+  uschar *hosts_avoid_esmtp;
+#ifndef DISABLE_TLS
+  uschar *hosts_nopass_tls;
+  uschar *hosts_noproxy_tls;
+#endif
+  int     command_timeout;
+  int     connect_timeout;
+  int     data_timeout;
+  int     final_timeout;
+  int     size_addition;
+  int     hosts_max_try;
+  int     hosts_max_try_hardlimit;
+  BOOL    address_retry_include_sender;
+  BOOL    allow_localhost;
+  BOOL    authenticated_sender_force;
+  BOOL    gethostbyname;
+  BOOL    dns_qualify_single;
+  BOOL    dns_search_parents;
+  dnssec_domains dnssec;
+  BOOL    delay_after_cutoff;
+  BOOL    hosts_override;
+  BOOL    hosts_randomize;
+  BOOL    keepalive;
+  BOOL    lmtp_ignore_quota;
+  uschar *expand_retry_include_ip_address;
+  BOOL    retry_include_ip_address;
+#ifdef SUPPORT_SOCKS
+  uschar *socks_proxy;
+#endif
+#ifndef DISABLE_TLS
+  uschar *tls_certificate;
+  uschar *tls_crl;
+  uschar *tls_privatekey;
+  uschar *tls_require_ciphers;
+# ifdef EXPERIMENTAL_TLS_RESUME
+  uschar *tls_resumption_hosts;
+# endif
+  const uschar *tls_sni;
+  uschar *tls_verify_certificates;
+  int     tls_dh_min_bits;
+  BOOL    tls_tempfail_tryclear;
+  uschar *tls_verify_hosts;
+  uschar *tls_try_verify_hosts;
+  uschar *tls_verify_cert_hostnames;
+#endif
+#ifdef SUPPORT_I18N
+  uschar *utf8_downconvert;
+#endif
+#ifndef DISABLE_DKIM
+  struct ob_dkim dkim;
+#endif
+#ifdef EXPERIMENTAL_ARC
+  uschar *arc_sign;
+#endif
+} smtp_transport_options_block;
+
+#define SOB (smtp_transport_options_block *)
+
+
+/* smtp connect context */
+typedef struct {
+  uschar *		from_addr;
+  address_item *	addrlist;
+
+  smtp_connect_args	conn_args;
+  int			port;
+
+  BOOL verify:1;
+  BOOL lmtp:1;
+  BOOL smtps:1;
+  BOOL ok:1;
+  BOOL setting_up:1;
+#ifndef DISABLE_PIPE_CONNECT
+  BOOL early_pipe_ok:1;
+  BOOL early_pipe_active:1;
+#endif
+  BOOL esmtp:1;
+  BOOL esmtp_sent:1;
+  BOOL pipelining_used:1;
+#ifndef DISABLE_PRDR
+  BOOL prdr_active:1;
+#endif
+#ifdef SUPPORT_I18N
+  BOOL utf8_needed:1;
+#endif
+  BOOL dsn_all_lasthop:1;
+#if !defined(DISABLE_TLS) && defined(SUPPORT_DANE)
+  BOOL dane_required:1;
+#endif
+#ifndef DISABLE_PIPE_CONNECT
+  BOOL pending_BANNER:1;
+  BOOL pending_EHLO:1;
+#endif
+  BOOL pending_MAIL:1;
+  BOOL pending_BDAT:1;
+  BOOL RCPT_452:1;
+  BOOL good_RCPT:1;
+  BOOL completed_addr:1;
+  BOOL send_rset:1;
+  BOOL send_quit:1;
+
+  int		max_rcpt;
+  int		cmd_count;
+
+  unsigned	peer_offered;
+  unsigned	avoid_option;
+  uschar *	igquotstr;
+  uschar *	helo_data;
+#ifdef EXPERIMENTAL_DSN_INFO
+  uschar *	smtp_greeting;
+  uschar *	helo_response;
+#endif
+#ifndef DISABLE_PIPE_CONNECT
+  ehlo_resp_precis	ehlo_resp;
+#endif
+
+  struct timeval	delivery_start;
+  address_item *	first_addr;
+  address_item *	next_addr;
+  address_item *	sync_addr;
+
+  client_conn_ctx	cctx;
+  smtp_inblock		inblock;
+  smtp_outblock		outblock;
+  uschar	buffer[DELIVER_BUFFER_SIZE];
+  uschar	inbuffer[4096];
+  uschar	outbuffer[4096];
+} smtp_context;
+
+extern int smtp_setup_conn(smtp_context *, BOOL);
+extern int smtp_write_mail_and_rcpt_cmds(smtp_context *, int *);
+extern int smtp_reap_early_pipe(smtp_context *, int *);
+
+
+/* Data for reading the private options. */
+
+extern optionlist smtp_transport_options[];
+extern int smtp_transport_options_count;
+
+/* Block containing default values. */
+
+extern smtp_transport_options_block smtp_transport_option_defaults;
+
+/* The main, init, and closedown entry points for the transport */
+
+extern BOOL smtp_transport_entry(transport_instance *, address_item *);
+extern void smtp_transport_init(transport_instance *);
+extern void smtp_transport_closedown(transport_instance *);
+
+
+
+#ifdef SUPPORT_SOCKS
+extern int     socks_sock_connect(host_item *, int, int, uschar *,
+	         transport_instance *, int);
+#endif
+
+/* End of transports/smtp.h */
diff --git a/src/transports/smtp_socks.c b/src/transports/smtp_socks.c
new file mode 100644
index 0000000..cd8ed3e
--- /dev/null
+++ b/src/transports/smtp_socks.c
@@ -0,0 +1,418 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+/* Copyright (c) Jeremy Harris 2015 - 2018 */
+/* See the file NOTICE for conditions of use and distribution. */
+
+/* SOCKS version 5 proxy, client-mode */
+
+#include "../exim.h"
+#include "smtp.h"
+
+#ifdef SUPPORT_SOCKS /* entire file */
+
+#ifndef nelem
+# define nelem(arr) (sizeof(arr)/sizeof(*arr))
+#endif
+
+
+/* Defaults */
+#define SOCKS_PORT	1080
+#define SOCKS_TIMEOUT	5
+#define SOCKS_WEIGHT	1
+#define SOCKS_PRIORITY	1
+
+#define AUTH_NONE	0
+#define AUTH_NAME	2		/* user/password per RFC 1929 */
+#define AUTH_NAME_VER	1
+
+struct socks_err
+  {
+  uschar *	reason;
+  int		errcode;
+  } socks_errs[] =
+  {
+    {NULL, 0},
+    {US"general SOCKS server failure",		EIO},
+    {US"connection not allowed by ruleset",	EACCES},
+    {US"Network unreachable",			ENETUNREACH},
+    {US"Host unreachable",			EHOSTUNREACH},
+    {US"Connection refused",			ECONNREFUSED},
+    {US"TTL expired",				ECANCELED},
+    {US"Command not supported",			EOPNOTSUPP},
+    {US"Address type not supported",		EAFNOSUPPORT}
+  };
+
+typedef struct
+  {
+  const uschar *	proxy_host;
+  uschar		auth_type;	/* RFC 1928 encoding */
+  const uschar *	auth_name;
+  const uschar *	auth_pwd;
+  short			port;
+  BOOL			is_failed;
+  unsigned		timeout;
+  unsigned		weight;
+  unsigned		priority;
+  } socks_opts;
+
+static void
+socks_option_defaults(socks_opts * sob)
+{
+sob->proxy_host = NULL;
+sob->auth_type =  AUTH_NONE;
+sob->auth_name =  US"";
+sob->auth_pwd =   US"";
+sob->is_failed =  FALSE;
+sob->port =	  SOCKS_PORT;
+sob->timeout =	  SOCKS_TIMEOUT;
+sob->weight =	  SOCKS_WEIGHT;
+sob->priority =   SOCKS_PRIORITY;
+}
+
+static void
+socks_option(socks_opts * sob, const uschar * opt)
+{
+if (Ustrncmp(opt, "auth=", 5) == 0)
+  {
+  opt += 5;
+  if (Ustrcmp(opt, "none") == 0) 	sob->auth_type = AUTH_NONE;
+  else if (Ustrcmp(opt, "name") == 0)	sob->auth_type = AUTH_NAME;
+  }
+else if (Ustrncmp(opt, "name=", 5) == 0)
+  sob->auth_name = opt + 5;
+else if (Ustrncmp(opt, "pass=", 5) == 0)
+  sob->auth_pwd = opt + 5;
+else if (Ustrncmp(opt, "port=", 5) == 0)
+  sob->port = atoi(CCS opt + 5);
+else if (Ustrncmp(opt, "tmo=", 4) == 0)
+  sob->timeout = atoi(CCS opt + 4);
+else if (Ustrncmp(opt, "pri=", 4) == 0)
+  sob->priority = atoi(CCS opt + 4);
+else if (Ustrncmp(opt, "weight=", 7) == 0)
+  sob->weight = atoi(CCS opt + 7);
+return;
+}
+
+static int
+socks_auth(int fd, int method, socks_opts * sob, time_t tmo)
+{
+uschar * s;
+int len, i, j;
+
+switch(method)
+  {
+  default:
+    log_write(0, LOG_MAIN|LOG_PANIC,
+      "Unrecognised socks auth method %d", method);
+    return FAIL;
+  case AUTH_NONE:
+    return OK;
+  case AUTH_NAME:
+    HDEBUG(D_transport|D_acl|D_v) debug_printf_indent("  socks auth NAME '%s' '%s'\n",
+      sob->auth_name, sob->auth_pwd);
+    i = Ustrlen(sob->auth_name);
+    j = Ustrlen(sob->auth_pwd);
+    s = string_sprintf("%c%c%.255s%c%.255s", AUTH_NAME_VER,
+      i, sob->auth_name, j, sob->auth_pwd);
+    len = i + j + 3;
+    HDEBUG(D_transport|D_acl|D_v)
+      {
+      debug_printf_indent("  SOCKS>>");
+      for (int i = 0; i<len; i++) debug_printf(" %02x", s[i]);
+      debug_printf("\n");
+      }
+    if (send(fd, s, len, 0) < 0)
+      return FAIL;
+#ifdef TCP_QUICKACK
+    (void) setsockopt(fd, IPPROTO_TCP, TCP_QUICKACK, US &off, sizeof(off));
+#endif
+    if (!fd_ready(fd, tmo) || read(fd, s, 2) != 2)
+      return FAIL;
+    HDEBUG(D_transport|D_acl|D_v)
+      debug_printf_indent("  SOCKS<< %02x %02x\n", s[0], s[1]);
+    if (s[0] == AUTH_NAME_VER && s[1] == 0)
+      {
+      HDEBUG(D_transport|D_acl|D_v) debug_printf_indent("  socks auth OK\n");
+      return OK;
+      }
+
+    log_write(0, LOG_MAIN|LOG_PANIC, "socks auth failed");
+    errno = EPROTO;
+    return FAIL;
+  }
+}
+
+
+
+/* Find a suitable proxy to use from the list.
+Possible common code with spamd_get_server() ?
+
+Return: index into proxy spec array, or -1
+*/
+
+static int
+socks_get_proxy(socks_opts * proxies, unsigned nproxies)
+{
+unsigned int i;
+socks_opts * sd;
+socks_opts * lim = &proxies[nproxies];
+long rnd, weights;
+unsigned pri;
+static BOOL srandomed = FALSE;
+
+if (nproxies == 1)		/* shortcut, if we have only 1 server */
+  return (proxies[0].is_failed ? -1 : 0);
+
+/* init random */
+if (!srandomed)
+  {
+  struct timeval tv;
+  gettimeofday(&tv, NULL);
+  srandom((unsigned int)(tv.tv_usec/1000));
+  srandomed = TRUE;
+  }
+
+/* scan for highest pri */
+for (pri = 0, sd = proxies; sd < lim; sd++)
+  if (!sd->is_failed && sd->priority > pri)
+    pri = sd->priority;
+
+/* get sum of weights at this pri */
+for (weights = 0, sd = proxies; sd < lim; sd++)
+  if (!sd->is_failed && sd->priority == pri)
+    weights += sd->weight;
+if (weights == 0)       /* all servers failed */
+  return -1;
+
+for (rnd = random() % weights, i = 0; i < nproxies; i++)
+  {
+  sd = &proxies[i];
+  if (!sd->is_failed && sd->priority == pri)
+    if ((rnd -= sd->weight) < 0)
+      return i;
+  }
+
+log_write(0, LOG_MAIN|LOG_PANIC,
+  "%s unknown error (memory/cpu corruption?)", __FUNCTION__);
+return -1;
+}
+
+
+
+/* Make a connection via a socks proxy
+
+Arguments:
+ host		smtp target host
+ host_af	address family
+ port		remote tcp port number
+ interface	local interface
+ tb		transport
+ timeout	connection timeout (zero for indefinite)
+
+Return value:
+ 0 on success; -1 on failure, with errno set
+*/
+
+int
+socks_sock_connect(host_item * host, int host_af, int port, uschar * interface,
+  transport_instance * tb, int timeout)
+{
+smtp_transport_options_block * ob =
+  (smtp_transport_options_block *)tb->options_block;
+const uschar * proxy_list;
+const uschar * proxy_spec;
+int sep = 0;
+int fd;
+time_t tmo;
+const uschar * state;
+uschar buf[24];
+socks_opts proxies[32];			/* max #proxies handled */
+unsigned nproxies;
+socks_opts * sob;
+unsigned size;
+blob early_data;
+
+if (!timeout) timeout = 24*60*60;	/* use 1 day for "indefinite" */
+tmo = time(NULL) + timeout;
+
+if (!(proxy_list = expand_string(ob->socks_proxy)))
+  {
+  log_write(0, LOG_MAIN|LOG_PANIC, "Bad expansion for socks_proxy in %s",
+    tb->name);
+  return -1;
+  }
+
+/* Read proxy list */
+
+for (nproxies = 0;
+        nproxies < nelem(proxies)
+     && (proxy_spec = string_nextinlist(&proxy_list, &sep, NULL, 0));
+     nproxies++)
+  {
+  int subsep = -' ';
+  const uschar * option;
+
+  socks_option_defaults(sob = &proxies[nproxies]);
+
+  if (!(sob->proxy_host = string_nextinlist(&proxy_spec, &subsep, NULL, 0)))
+    {
+    /* paniclog config error */
+    return -1;
+    }
+
+  /*XXX consider global options eg. "hide socks_password = wibble" on the tpt */
+  /* extract any further per-proxy options */
+  while ((option = string_nextinlist(&proxy_spec, &subsep, NULL, 0)))
+    socks_option(sob, option);
+  }
+
+/* Set up the socks protocol method-selection message,
+for sending on connection */
+
+state = US"method select";
+buf[0] = 5; buf[1] = 1; buf[2] = sob->auth_type;
+early_data.data = buf;
+early_data.len = 3;
+
+/* Try proxies until a connection succeeds */
+
+for(;;)
+  {
+  int idx;
+  host_item proxy;
+  int proxy_af;
+
+  if ((idx = socks_get_proxy(proxies, nproxies)) < 0)
+    {
+    HDEBUG(D_transport|D_acl|D_v) debug_printf_indent("  no proxies left\n");
+    errno = EBUSY;
+    return -1;
+    }
+  sob = &proxies[idx];
+
+  /* bodge up a host struct for the proxy */
+  proxy.address = proxy.name = sob->proxy_host;
+  proxy_af = Ustrchr(sob->proxy_host, ':') ? AF_INET6 : AF_INET;
+
+  /*XXX we trust that the method-select command is idempotent */
+  if ((fd = smtp_sock_connect(&proxy, proxy_af, sob->port,
+	      interface, tb, sob->timeout, &early_data)) >= 0)
+    {
+    proxy_local_address = string_copy(proxy.address);
+    proxy_local_port = sob->port;
+    break;
+    }
+
+  log_write(0, LOG_MAIN, "%s: %s", __FUNCTION__, strerror(errno));
+  sob->is_failed = TRUE;
+  }
+
+/* Do the socks protocol stuff */
+
+HDEBUG(D_transport|D_acl|D_v) debug_printf_indent("  SOCKS>> 05 01 %02x\n", sob->auth_type);
+
+/* expect method response */
+
+#ifdef TCP_QUICKACK
+(void) setsockopt(fd, IPPROTO_TCP, TCP_QUICKACK, US &off, sizeof(off));
+#endif
+
+if (  !fd_ready(fd, tmo)
+   || read(fd, buf, 2) != 2
+   )
+  goto rcv_err;
+HDEBUG(D_transport|D_acl|D_v)
+  debug_printf_indent("  SOCKS<< %02x %02x\n", buf[0], buf[1]);
+if (  buf[0] != 5
+   || socks_auth(fd, buf[1], sob, tmo) != OK
+   )
+  goto proxy_err;
+
+  {
+  union sockaddr_46 sin;
+  (void) ip_addr(&sin, host_af, host->address, port);
+
+  /* send connect (ipver, ipaddr, port) */
+
+  buf[0] = 5; buf[1] = 1; buf[2] = 0; buf[3] = host_af == AF_INET6 ? 4 : 1;
+  #if HAVE_IPV6
+  if (host_af == AF_INET6)
+    {
+    memcpy(buf+4, &sin.v6.sin6_addr,       sizeof(sin.v6.sin6_addr));
+    memcpy(buf+4+sizeof(sin.v6.sin6_addr),
+      &sin.v6.sin6_port, sizeof(sin.v6.sin6_port));
+    size = 4+sizeof(sin.v6.sin6_addr)+sizeof(sin.v6.sin6_port);
+    }
+  else
+  #endif
+    {
+    memcpy(buf+4, &sin.v4.sin_addr.s_addr, sizeof(sin.v4.sin_addr.s_addr));
+    memcpy(buf+4+sizeof(sin.v4.sin_addr.s_addr),
+      &sin.v4.sin_port, sizeof(sin.v4.sin_port));
+    size = 4+sizeof(sin.v4.sin_addr.s_addr)+sizeof(sin.v4.sin_port);
+    }
+  }
+
+state = US"connect";
+HDEBUG(D_transport|D_acl|D_v)
+  {
+  debug_printf_indent("  SOCKS>>");
+  for (int i = 0; i<size; i++) debug_printf(" %02x", buf[i]);
+  debug_printf("\n");
+  }
+if (send(fd, buf, size, 0) < 0)
+  goto snd_err;
+
+/* expect conn-reply (success, local(ipver, addr, port))
+of same length as conn-request, or non-success fail code */
+
+if (  !fd_ready(fd, tmo)
+   || (size = read(fd, buf, size)) < 2
+   )
+  goto rcv_err;
+HDEBUG(D_transport|D_acl|D_v)
+  {
+  debug_printf_indent("  SOCKS>>");
+  for (int i = 0; i<size; i++) debug_printf(" %02x", buf[i]);
+  debug_printf("\n");
+  }
+if (  buf[0] != 5
+   || buf[1] != 0
+   )
+  goto proxy_err;
+
+proxy_external_address = string_copy(
+  host_ntoa(buf[3] == 4 ? AF_INET6 : AF_INET, buf+4, NULL, NULL));
+proxy_external_port = ntohs(*((uint16_t *)(buf + (buf[3] == 4 ? 20 : 8))));
+proxy_session = TRUE;
+
+HDEBUG(D_transport|D_acl|D_v)
+  debug_printf_indent("  proxy farside: [%s]:%d\n", proxy_external_address, proxy_external_port);
+
+return fd;
+
+snd_err:
+  HDEBUG(D_transport|D_acl|D_v) debug_printf_indent("  proxy snd_err %s: %s\n", state, strerror(errno));
+  return -1;
+
+proxy_err:
+  {
+  struct socks_err * se =
+    buf[1] > nelem(socks_errs) ? NULL : socks_errs + buf[1];
+  HDEBUG(D_transport|D_acl|D_v)
+    debug_printf_indent("  proxy %s: %s\n", state, se ? se->reason : US"unknown error code received");
+  errno = se ? se->errcode : EPROTO;
+  }
+
+rcv_err:
+  HDEBUG(D_transport|D_acl|D_v) debug_printf_indent("  proxy rcv_err %s: %s\n", state, strerror(errno));
+  if (!errno) errno = EPROTO;
+  else if (errno == ENOENT) errno = ECONNABORTED;
+  return -1;
+}
+
+#endif	/* entire file */
+/* vi: aw ai sw=2
+*/
diff --git a/src/transports/tf_maildir.c b/src/transports/tf_maildir.c
new file mode 100644
index 0000000..cd1964a
--- /dev/null
+++ b/src/transports/tf_maildir.c
@@ -0,0 +1,584 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+/* Copyright (c) University of Cambridge 1995 - 2018 */
+/* Copyright (c) The Exim Maintainers 2020 */
+/* See the file NOTICE for conditions of use and distribution. */
+
+/* Functions in support of the use of maildirsize files for handling quotas in
+maildir directories. Some of the rules are a bit baroque:
+
+http://www.inter7.com/courierimap/README.maildirquota.html
+
+We try to follow most of that, except that the directories to skip for quota
+calculations are not hard wired in, but are supplied as a regex. */
+
+
+#include "../exim.h"
+#include "appendfile.h"
+#include "tf_maildir.h"
+
+#define MAX_FILE_SIZE  5120
+
+
+
+/*************************************************
+*      Ensure maildir directories exist          *
+*************************************************/
+
+/* This function is called at the start of a maildir delivery, to ensure that
+all the relevant directories exist. It also creates a maildirfolder file if the
+base directory matches a given pattern.
+
+Argument:
+  path              the base directory name
+  addr              the address item (for setting an error message)
+  create_directory  true if we are allowed to create missing directories
+  dirmode           the mode for created directories
+  maildirfolder_create_regex
+                    the pattern to match for maildirfolder creation
+
+Returns:            TRUE on success; FALSE on failure
+*/
+
+BOOL maildir_ensure_directories(uschar *path, address_item *addr,
+  BOOL create_directory, int dirmode, uschar *maildirfolder_create_regex)
+{
+int i;
+struct stat statbuf;
+const char *subdirs[] = { "/tmp", "/new", "/cur" };
+
+DEBUG(D_transport)
+  debug_printf("ensuring maildir directories exist in %s\n", path);
+
+/* First ensure that the path we have is a directory; if it does not exist,
+create it. Then make sure the tmp, new & cur subdirs of the maildir are
+there. If not, fail. This aborts the delivery (even though the cur subdir is
+not actually needed for delivery). Handle all 4 directory tests/creates in a
+loop so that code can be shared. */
+
+for (i = 0; i < 4; i++)
+  {
+  int j;
+  const uschar *dir, *mdir;
+
+  if (i == 0)
+    {
+    mdir = CUS"";
+    dir = path;
+    }
+  else
+    {
+    mdir = CUS subdirs[i-1];
+    dir = mdir + 1;
+    }
+
+  /* Check an existing path is a directory. This is inside a loop because
+  there is a potential race condition when creating the directory - some
+  other process may get there first. Give up after trying several times,
+  though. */
+
+  for (j = 0; j < 10; j++)
+    {
+    if (Ustat(dir, &statbuf) == 0)
+      {
+      if (S_ISDIR(statbuf.st_mode)) break;   /* out of the race loop */
+      addr->message = string_sprintf("%s%s is not a directory", path,
+        mdir);
+      addr->basic_errno = ERRNO_NOTDIRECTORY;
+      return FALSE;
+      }
+
+    /* Try to make if non-existent and configured to do so */
+
+    if (errno == ENOENT && create_directory)
+      {
+      if (!directory_make(NULL, dir, dirmode, FALSE))
+        {
+        if (errno == EEXIST) continue;     /* repeat the race loop */
+        addr->message = string_sprintf("cannot create %s%s", path, mdir);
+        addr->basic_errno = errno;
+        return FALSE;
+        }
+      DEBUG(D_transport)
+        debug_printf("created directory %s%s\n", path, mdir);
+      break;   /* out of the race loop */
+      }
+
+    /* stat() error other than ENOENT, or ENOENT and not creatable */
+
+    addr->message = string_sprintf("stat() error for %s%s: %s", path, mdir,
+      strerror(errno));
+    addr->basic_errno = errno;
+    return FALSE;
+    }
+
+  /* If we went round the loop 10 times, the directory was flickering in
+  and out of existence like someone in a malfunctioning Star Trek
+  transporter. */
+
+  if (j >= 10)
+    {
+    addr->message = string_sprintf("existence of %s%s unclear\n", path,
+      mdir);
+    addr->basic_errno = errno;
+    addr->special_action = SPECIAL_FREEZE;
+    return FALSE;
+    }
+
+  /* First time through the directories loop, cd to the main directory */
+
+  if (i == 0 && Uchdir(path) != 0)
+    {
+    addr->message = string_sprintf ("cannot chdir to %s", path);
+    addr->basic_errno = errno;
+    return FALSE;
+    }
+  }
+
+/* If the basic path matches maildirfolder_create_regex, we are dealing with
+a subfolder, and should ensure that a maildirfolder file exists. */
+
+if (maildirfolder_create_regex != NULL)
+  {
+  const uschar *error;
+  int offset;
+  const pcre *regex;
+
+  DEBUG(D_transport) debug_printf("checking for maildirfolder requirement\n");
+
+  if (!(regex = pcre_compile(CS maildirfolder_create_regex, PCRE_COPT,
+    CCSS &error, &offset, NULL)))
+    {
+    addr->message = string_sprintf("appendfile: regular expression "
+      "error: %s at offset %d while compiling %s", error, offset,
+      maildirfolder_create_regex);
+    return FALSE;
+    }
+
+  if (pcre_exec(regex, NULL, CS path, Ustrlen(path), 0, 0, NULL, 0) >= 0)
+    {
+    uschar *fname = string_sprintf("%s/maildirfolder", path);
+    if (Ustat(fname, &statbuf) == 0)
+      {
+      DEBUG(D_transport) debug_printf("maildirfolder already exists\n");
+      }
+    else
+      {
+      int fd = Uopen(fname, O_WRONLY|O_APPEND|O_CREAT, 0600);
+      if (fd < 0)
+        {
+        addr->message = string_sprintf("appendfile: failed to create "
+          "maildirfolder file in %s directory: %s", path, strerror(errno));
+        return FALSE;
+        }
+      (void)close(fd);
+      DEBUG(D_transport) debug_printf("created maildirfolder file\n");
+      }
+    }
+  else
+    {
+    DEBUG(D_transport) debug_printf("maildirfolder file not required\n");
+    }
+  }
+
+return TRUE;   /* Everything exists that should exist */
+}
+
+
+
+
+/*************************************************
+*       Update maildirsizefile for new file      *
+*************************************************/
+
+/* This function is called to add a new line to the file, recording the length
+of the newly added message. There isn't much we can do on failure...
+
+Arguments:
+  fd           the open file descriptor
+  size         the size of the message
+
+Returns:       nothing
+*/
+
+void
+maildir_record_length(int fd, int size)
+{
+int len;
+uschar buffer[256];
+sprintf(CS buffer, "%d 1\n", size);
+len = Ustrlen(buffer);
+if (lseek(fd, 0, SEEK_END) >= 0)
+  {
+  len = write(fd, buffer, len);
+  DEBUG(D_transport)
+    debug_printf("added '%.*s' to maildirsize file\n", len-1, buffer);
+  }
+}
+
+
+
+/*************************************************
+*          Find the size of a maildir            *
+*************************************************/
+
+/* This function is called when we have to recalculate the size of a maildir by
+scanning all the files and directories therein. There are rules and conventions
+about which files or directories are included. We support this by the use of a
+regex to match directories that are to be included.
+
+Maildirs can only be one level deep. However, this function recurses, so it
+might cope with deeper nestings. We use the existing check_dir_size() function
+to add up the sizes of the files in a directory that contains messages.
+
+The function returns the most recent timestamp encountered. It can also be run
+in a dummy mode in which it does not scan for sizes, but just returns the
+timestamp.
+
+Arguments:
+  path            the path to the maildir
+  filecount       where to store the count of messages
+  latest          where to store the latest timestamp encountered
+  regex           a regex for getting files sizes from file names
+  dir_regex       a regex for matching directories to be included
+  timestamp_only  don't actually compute any sizes
+
+Returns:      the sum of the sizes of the messages
+*/
+
+off_t
+maildir_compute_size(uschar *path, int *filecount, time_t *latest,
+  const pcre *regex, const pcre *dir_regex, BOOL timestamp_only)
+{
+DIR *dir;
+off_t sum = 0;
+
+if (!(dir = exim_opendir(path)))
+  return 0;
+
+for (struct dirent *ent; ent = readdir(dir); )
+  {
+  uschar * s, * name = US ent->d_name;
+  struct stat statbuf;
+
+  if (Ustrcmp(name, ".") == 0 || Ustrcmp(name, "..") == 0) continue;
+
+  /* We are normally supplied with a regex for choosing which directories to
+  scan. We do the regex match first, because that avoids a stat() for names
+  we aren't interested in. */
+
+  if (dir_regex != NULL &&
+      pcre_exec(dir_regex, NULL, CS name, Ustrlen(name), 0, 0, NULL, 0) < 0)
+    {
+    DEBUG(D_transport)
+      debug_printf("skipping %s/%s: dir_regex does not match\n", path, name);
+    continue;
+    }
+
+  /* The name is OK; stat it. */
+
+  s = string_sprintf("%s/%s", path, name);
+  if (Ustat(s, &statbuf) < 0)
+    {
+    DEBUG(D_transport)
+      debug_printf("maildir_compute_size: stat error %d for %s: %s\n", errno,
+        s, strerror(errno));
+    continue;
+    }
+
+  if ((statbuf.st_mode & S_IFMT) != S_IFDIR)
+    {
+    DEBUG(D_transport)
+      debug_printf("skipping %s/%s: not a directory\n", s, name);
+    continue;
+    }
+
+  /* Keep the latest timestamp encountered */
+
+  if (statbuf.st_mtime > *latest) *latest = statbuf.st_mtime;
+
+  /* If this is a maildir folder, call this function recursively. */
+
+  if (name[0] == '.')
+    sum += maildir_compute_size(s, filecount, latest, regex, dir_regex,
+      timestamp_only);
+
+  /* Otherwise it must be a folder that contains messages (e.g. new or cur), so
+  we need to get its size, unless all we are interested in is the timestamp. */
+
+  else if (!timestamp_only)
+    sum += check_dir_size(s, filecount, regex);
+  }
+
+closedir(dir);
+DEBUG(D_transport)
+  {
+  if (timestamp_only)
+    debug_printf("maildir_compute_size (timestamp_only): %ld\n",
+    (long int) *latest);
+  else
+    debug_printf("maildir_compute_size: path=%s\n  sum=" OFF_T_FMT
+      " filecount=%d timestamp=%ld\n",
+      path, sum, *filecount, (long int) *latest);
+  }
+return sum;
+}
+
+
+
+/*************************************************
+*        Create or update maildirsizefile        *
+*************************************************/
+
+/* This function is called before a delivery if the option to use
+maildirsizefile is enabled. Its function is to create the file if it does not
+exist, or to update it if that is necessary.
+
+The logic in this function follows the rules that are described in
+
+  http://www.inter7.com/courierimap/README.maildirquota.html
+
+Or, at least, it is supposed to!
+
+Arguments:
+  path             the path to the maildir directory; this is already backed-up
+                     to the parent if the delivery directory is a maildirfolder
+  ob               the appendfile options block
+  regex            a compiled regex for getting a file's size from its name
+  dir_regex        a compiled regex for selecting maildir directories
+  returned_size    where to return the current size of the maildir, even if
+                     the maildirsizefile is removed because of a race
+
+Returns:           >=0  a file descriptor for an open maildirsize file
+                   -1   there was an error opening or accessing the file
+                   -2   the file was removed because of a race
+*/
+
+int
+maildir_ensure_sizefile(uschar *path, appendfile_transport_options_block *ob,
+  const pcre *regex, const pcre *dir_regex, off_t *returned_size,
+  int *returned_filecount)
+{
+int count, fd;
+off_t cached_quota = 0;
+int cached_quota_filecount = 0;
+int filecount = 0;
+int linecount = 0;
+off_t size = 0;
+uschar *filename;
+uschar buffer[MAX_FILE_SIZE];
+uschar *ptr = buffer;
+uschar *endptr;
+
+/* Try a few times to open or create the file, in case another process is doing
+the same thing. */
+
+filename = string_sprintf("%s/maildirsize", path);
+
+DEBUG(D_transport) debug_printf("looking for maildirsize in %s\n", path);
+if ((fd = Uopen(filename, O_RDWR|O_APPEND, ob->mode ? ob->mode : 0600)) < 0)
+  {
+  if (errno != ENOENT) return -1;
+  DEBUG(D_transport)
+    debug_printf("%s does not exist: recalculating\n", filename);
+  goto RECALCULATE;
+  }
+
+/* The file has been successfully opened. Check that the cached quota value is
+still correct, and that the size of the file is still small enough. If so,
+compute the maildir size from the file. */
+
+if ((count = read(fd, buffer, sizeof(buffer))) >= sizeof(buffer))
+  {
+  DEBUG(D_transport)
+    debug_printf("maildirsize file too big (%d): recalculating\n", count);
+  goto RECALCULATE;
+  }
+buffer[count] = 0;   /* Ensure string terminated */
+
+/* Read the quota parameters from the first line of the data. */
+
+DEBUG(D_transport)
+  debug_printf("reading quota parameters from maildirsize data\n");
+
+for (;;)
+  {
+  off_t n = (off_t)Ustrtod(ptr, &endptr);
+
+  /* Only two data items are currently defined; ignore any others that
+  may be present. The spec is for a number followed by a letter. Anything
+  else we reject and recalculate. */
+
+  if (*endptr == 'S') cached_quota = n;
+    else if (*endptr == 'C') cached_quota_filecount = (int)n;
+  if (!isalpha(*endptr++))
+    {
+    DEBUG(D_transport)
+      debug_printf("quota parameter number not followed by letter in "
+        "\"%.*s\": recalculating maildirsize\n", (int)(endptr - buffer),
+        buffer);
+    goto RECALCULATE;
+    }
+  if (*endptr == '\n' || *endptr == 0) break;
+  if (*endptr++ != ',')
+    {
+    DEBUG(D_transport)
+      debug_printf("quota parameter not followed by comma in "
+        "\"%.*s\": recalculating maildirsize\n", (int)(endptr - buffer),
+        buffer);
+    goto RECALCULATE;
+    }
+  ptr = endptr;
+  }
+
+/* Check the cached values against the current settings */
+
+if (cached_quota != ob->quota_value ||
+    cached_quota_filecount != ob->quota_filecount_value)
+  {
+  DEBUG(D_transport)
+    debug_printf("cached quota is out of date: recalculating\n"
+      "  quota=" OFF_T_FMT " cached_quota=" OFF_T_FMT " filecount_quota=%d "
+      "cached_quota_filecount=%d\n", ob->quota_value,
+      cached_quota, ob->quota_filecount_value, cached_quota_filecount);
+  goto RECALCULATE;
+  }
+
+/* Quota values agree; parse the rest of the data to get the sizes. At this
+stage, *endptr points either to 0 or to '\n'.  */
+
+DEBUG(D_transport)
+  debug_printf("computing maildir size from maildirsize data\n");
+
+while (*endptr++ == '\n')
+  {
+  if (*endptr == 0) break;
+  linecount++;
+  ptr = endptr;
+  size += (off_t)Ustrtod(ptr, &endptr);
+  if (*endptr != ' ') break;
+  ptr = endptr + 1;
+  filecount += Ustrtol(ptr, &endptr, 10);
+  }
+
+/* If *endptr is zero, we have successfully parsed the file, and we now have
+the size of the mailbox as cached in the file. The "rules" say that if this
+value indicates that the mailbox is over quota, we must recalculate if there is
+more than one entry in the file, or if the file is older than 15 minutes. Also,
+just in case there are weird values in the file, recalculate if either of the
+values is negative. */
+
+if (*endptr == 0)
+  {
+  if (size < 0 || filecount < 0)
+    {
+    DEBUG(D_transport) debug_printf("negative value in maildirsize "
+      "(size=" OFF_T_FMT " count=%d): recalculating\n", size, filecount);
+    goto RECALCULATE;
+    }
+
+  if (ob->quota_value > 0 &&
+      (size + (ob->quota_is_inclusive? message_size : 0) > ob->quota_value ||
+        (ob->quota_filecount_value > 0 &&
+          filecount + (ob->quota_is_inclusive ? 1:0) >
+            ob->quota_filecount_value)
+      ))
+    {
+    struct stat statbuf;
+    if (linecount > 1)
+      {
+      DEBUG(D_transport) debug_printf("over quota and maildirsize has "
+        "more than 1 entry: recalculating\n");
+      goto RECALCULATE;
+      }
+
+    if (fstat(fd, &statbuf) < 0) goto RECALCULATE;  /* Should never occur */
+
+    if (time(NULL) - statbuf.st_mtime > 15*60)
+      {
+      DEBUG(D_transport) debug_printf("over quota and maildirsize is older "
+        "than 15 minutes: recalculating\n");
+      goto RECALCULATE;
+      }
+    }
+  }
+
+
+/* If *endptr is not zero, there was a syntax error in the file. */
+
+else
+  {
+  int len;
+  time_t old_latest, new_latest;
+  uschar *tempname;
+  struct timeval tv;
+
+  DEBUG(D_transport)
+    {
+    uschar *p = endptr;
+    while (p > buffer && p[-1] != '\n') p--;
+    endptr[1] = 0;
+
+    debug_printf("error in maildirsizefile: unexpected character %d in "
+      "line %d (starting '%s'): recalculating\n",
+      *endptr, linecount + 1, string_printing(p));
+    }
+
+  /* Either there is no file, or the quota value has changed, or the file has
+  got too big, or there was some format error in the file. Recalculate the size
+  and write new contents to a temporary file; then rename it. After any
+  error, just return -1 as the file descriptor. */
+
+  RECALCULATE:
+
+  if (fd >= 0) (void)close(fd);
+  old_latest = 0;
+  filecount = 0;
+  size = maildir_compute_size(path, &filecount, &old_latest, regex, dir_regex,
+    FALSE);
+
+  (void)gettimeofday(&tv, NULL);
+  tempname = string_sprintf("%s/tmp/" TIME_T_FMT ".H%luP%lu.%s",
+    path, tv.tv_sec, tv.tv_usec, (long unsigned) getpid(), primary_hostname);
+
+  fd = Uopen(tempname, O_RDWR|O_CREAT|O_EXCL, ob->mode ? ob->mode : 0600);
+  if (fd >= 0)
+    {
+    (void)sprintf(CS buffer, OFF_T_FMT "S,%dC\n" OFF_T_FMT " %d\n",
+      ob->quota_value, ob->quota_filecount_value, size, filecount);
+    len = Ustrlen(buffer);
+    if (write(fd, buffer, len) != len || Urename(tempname, filename) < 0)
+      {
+      (void)close(fd);
+      fd = -1;
+      }
+    }
+
+  /* If any of the directories have been modified since the last timestamp we
+  saw, we have to junk this maildirsize file. */
+
+  DEBUG(D_transport) debug_printf("checking subdirectory timestamps\n");
+  new_latest = 0;
+  (void)maildir_compute_size(path, NULL, &new_latest , NULL, dir_regex, TRUE);
+  if (new_latest > old_latest)
+    {
+    DEBUG(D_transport) debug_printf("abandoning maildirsize because of "
+      "a later subdirectory modification\n");
+    (void)Uunlink(filename);
+    (void)close(fd);
+    fd = -2;
+    }
+  }
+
+/* Return the sizes and the file descriptor, if any */
+
+DEBUG(D_transport) debug_printf("returning maildir size=" OFF_T_FMT
+  " filecount=%d\n", size, filecount);
+*returned_size = size;
+*returned_filecount = filecount;
+return fd;
+}
+
+/* End of tf_maildir.c */
diff --git a/src/transports/tf_maildir.h b/src/transports/tf_maildir.h
new file mode 100644
index 0000000..0be6bc4
--- /dev/null
+++ b/src/transports/tf_maildir.h
@@ -0,0 +1,20 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+/* Copyright (c) University of Cambridge 1995 - 2009 */
+/* See the file NOTICE for conditions of use and distribution. */
+
+/* Header file for the functions that are used to support the use of
+maildirsize files for quota handling in maildir directories. */
+
+extern off_t  maildir_compute_size(uschar *, int *, time_t *, const pcre *,
+                const pcre *, BOOL);
+extern BOOL   maildir_ensure_directories(uschar *, address_item *, BOOL, int,
+                uschar *);
+extern int    maildir_ensure_sizefile(uschar *,
+                appendfile_transport_options_block *, const pcre *,
+                const pcre *, off_t *, int *);
+extern void   maildir_record_length(int, int);
+
+/* End of tf_maildir.h */