diff options
Diffstat (limited to 'src/transports/appendfile.c')
| -rw-r--r-- | src/transports/appendfile.c | 3318 |
1 files changed, 3318 insertions, 0 deletions
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, ×); + +/* 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 */ |