Adding upstream version 4.96.upstream/4.96upstream

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

1 files changed, 585 insertions, 0 deletions

diff --git a/src/transports/tf_maildir.c b/src/transports/tf_maildir.c
new file mode 100644
index 0000000..a83fc6f
--- /dev/null
+++ b/src/transports/tf_maildir.c
@@ -0,0 +1,585 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+/* Copyright (c) University of Cambridge 1995 - 2018 */
+/* Copyright (c) The Exim Maintainers 2020 - 2021 */
+/* See the file NOTICE for conditions of use and distribution. */
+
+/* Functions in support of the use of maildirsize files for handling quotas in
+maildir directories. Some of the rules are a bit baroque:
+
+http://www.inter7.com/courierimap/README.maildirquota.html
+
+We try to follow most of that, except that the directories to skip for quota
+calculations are not hard wired in, but are supplied as a regex. */
+
+
+#include "../exim.h"
+#include "appendfile.h"
+#include "tf_maildir.h"
+
+#define MAX_FILE_SIZE  5120
+
+
+
+/*************************************************
+*      Ensure maildir directories exist          *
+*************************************************/
+
+/* This function is called at the start of a maildir delivery, to ensure that
+all the relevant directories exist. It also creates a maildirfolder file if the
+base directory matches a given pattern.
+
+Argument:
+  path              the base directory name
+  addr              the address item (for setting an error message)
+  create_directory  true if we are allowed to create missing directories
+  dirmode           the mode for created directories
+  maildirfolder_create_regex
+                    the pattern to match for maildirfolder creation
+
+Returns:            TRUE on success; FALSE on failure
+*/
+
+BOOL maildir_ensure_directories(uschar *path, address_item *addr,
+  BOOL create_directory, int dirmode, uschar *maildirfolder_create_regex)
+{
+int i;
+struct stat statbuf;
+const char *subdirs[] = { "/tmp", "/new", "/cur" };
+
+DEBUG(D_transport)
+  debug_printf("ensuring maildir directories exist in %s\n", path);
+
+/* First ensure that the path we have is a directory; if it does not exist,
+create it. Then make sure the tmp, new & cur subdirs of the maildir are
+there. If not, fail. This aborts the delivery (even though the cur subdir is
+not actually needed for delivery). Handle all 4 directory tests/creates in a
+loop so that code can be shared. */
+
+for (i = 0; i < 4; i++)
+  {
+  int j;
+  const uschar *dir, *mdir;
+
+  if (i == 0)
+    {
+    mdir = CUS"";
+    dir = path;
+    }
+  else
+    {
+    mdir = CUS subdirs[i-1];
+    dir = mdir + 1;
+    }
+
+  /* Check an existing path is a directory. This is inside a loop because
+  there is a potential race condition when creating the directory - some
+  other process may get there first. Give up after trying several times,
+  though. */
+
+  for (j = 0; j < 10; j++)
+    {
+    if (Ustat(dir, &statbuf) == 0)
+      {
+      if (S_ISDIR(statbuf.st_mode)) break;   /* out of the race loop */
+      addr->message = string_sprintf("%s%s is not a directory", path,
+        mdir);
+      addr->basic_errno = ERRNO_NOTDIRECTORY;
+      return FALSE;
+      }
+
+    /* Try to make if non-existent and configured to do so */
+
+    if (errno == ENOENT && create_directory)
+      {
+      if (!directory_make(NULL, dir, dirmode, FALSE))
+        {
+        if (errno == EEXIST) continue;     /* repeat the race loop */
+        addr->message = string_sprintf("cannot create %s%s", path, mdir);
+        addr->basic_errno = errno;
+        return FALSE;
+        }
+      DEBUG(D_transport)
+        debug_printf("created directory %s%s\n", path, mdir);
+      break;   /* out of the race loop */
+      }
+
+    /* stat() error other than ENOENT, or ENOENT and not creatable */
+
+    addr->message = string_sprintf("stat() error for %s%s: %s", path, mdir,
+      strerror(errno));
+    addr->basic_errno = errno;
+    return FALSE;
+    }
+
+  /* If we went round the loop 10 times, the directory was flickering in
+  and out of existence like someone in a malfunctioning Star Trek
+  transporter. */
+
+  if (j >= 10)
+    {
+    addr->message = string_sprintf("existence of %s%s unclear\n", path,
+      mdir);
+    addr->basic_errno = errno;
+    addr->special_action = SPECIAL_FREEZE;
+    return FALSE;
+    }
+
+  /* First time through the directories loop, cd to the main directory */
+
+  if (i == 0 && Uchdir(path) != 0)
+    {
+    addr->message = string_sprintf ("cannot chdir to %s", path);
+    addr->basic_errno = errno;
+    return FALSE;
+    }
+  }
+
+/* If the basic path matches maildirfolder_create_regex, we are dealing with
+a subfolder, and should ensure that a maildirfolder file exists. */
+
+if (maildirfolder_create_regex)
+  {
+  int err;
+  PCRE2_SIZE offset;
+  const pcre2_code * re;
+
+  DEBUG(D_transport) debug_printf("checking for maildirfolder requirement\n");
+
+  if (!(re = pcre2_compile((PCRE2_SPTR)maildirfolder_create_regex,
+	      PCRE2_ZERO_TERMINATED, PCRE_COPT, &err, &offset, pcre_cmp_ctx)))
+    {
+    uschar errbuf[128];
+    pcre2_get_error_message(err, errbuf, sizeof(errbuf));
+    addr->message = string_sprintf("appendfile: regular expression "
+      "error: %s at offset %ld while compiling %s", errbuf, (long)offset,
+      maildirfolder_create_regex);
+    return FALSE;
+    }
+
+  if (regex_match(re, path, -1, NULL))
+    {
+    uschar *fname = string_sprintf("%s/maildirfolder", path);
+    if (Ustat(fname, &statbuf) == 0)
+      {
+      DEBUG(D_transport) debug_printf("maildirfolder already exists\n");
+      }
+    else
+      {
+      int fd = Uopen(fname, O_WRONLY|O_APPEND|O_CREAT, 0600);
+      if (fd < 0)
+        {
+        addr->message = string_sprintf("appendfile: failed to create "
+          "maildirfolder file in %s directory: %s", path, strerror(errno));
+        return FALSE;
+        }
+      (void)close(fd);
+      DEBUG(D_transport) debug_printf("created maildirfolder file\n");
+      }
+    }
+  else
+    {
+    DEBUG(D_transport) debug_printf("maildirfolder file not required\n");
+    }
+  }
+
+return TRUE;   /* Everything exists that should exist */
+}
+
+
+
+
+/*************************************************
+*       Update maildirsizefile for new file      *
+*************************************************/
+
+/* This function is called to add a new line to the file, recording the length
+of the newly added message. There isn't much we can do on failure...
+
+Arguments:
+  fd           the open file descriptor
+  size         the size of the message
+
+Returns:       nothing
+*/
+
+void
+maildir_record_length(int fd, int size)
+{
+int len;
+uschar buffer[256];
+sprintf(CS buffer, "%d 1\n", size);
+len = Ustrlen(buffer);
+if (lseek(fd, 0, SEEK_END) >= 0)
+  {
+  len = write(fd, buffer, len);
+  DEBUG(D_transport)
+    debug_printf("added '%.*s' to maildirsize file\n", len-1, buffer);
+  }
+}
+
+
+
+/*************************************************
+*          Find the size of a maildir            *
+*************************************************/
+
+/* This function is called when we have to recalculate the size of a maildir by
+scanning all the files and directories therein. There are rules and conventions
+about which files or directories are included. We support this by the use of a
+regex to match directories that are to be included.
+
+Maildirs can only be one level deep. However, this function recurses, so it
+might cope with deeper nestings. We use the existing check_dir_size() function
+to add up the sizes of the files in a directory that contains messages.
+
+The function returns the most recent timestamp encountered. It can also be run
+in a dummy mode in which it does not scan for sizes, but just returns the
+timestamp.
+
+Arguments:
+  path            the path to the maildir
+  filecount       where to store the count of messages
+  latest          where to store the latest timestamp encountered
+  regex           a regex for getting files sizes from file names
+  dir_regex       a regex for matching directories to be included
+  timestamp_only  don't actually compute any sizes
+
+Returns:      the sum of the sizes of the messages
+*/
+
+off_t
+maildir_compute_size(uschar *path, int *filecount, time_t *latest,
+  const pcre2_code *regex, const pcre2_code *dir_regex, BOOL timestamp_only)
+{
+DIR *dir;
+off_t sum = 0;
+
+if (!(dir = exim_opendir(path)))
+  return 0;
+
+for (struct dirent *ent; ent = readdir(dir); )
+  {
+  uschar * s, * name = US ent->d_name;
+  struct stat statbuf;
+
+  if (Ustrcmp(name, ".") == 0 || Ustrcmp(name, "..") == 0) continue;
+
+  /* We are normally supplied with a regex for choosing which directories to
+  scan. We do the regex match first, because that avoids a stat() for names
+  we aren't interested in. */
+
+  if (dir_regex && !regex_match(dir_regex, name, -1, NULL))
+    {
+    DEBUG(D_transport)
+      debug_printf("skipping %s/%s: dir_regex does not match\n", path, name);
+    continue;
+    }
+
+  /* The name is OK; stat it. */
+
+  s = string_sprintf("%s/%s", path, name);
+  if (Ustat(s, &statbuf) < 0)
+    {
+    DEBUG(D_transport)
+      debug_printf("maildir_compute_size: stat error %d for %s: %s\n", errno,
+        s, strerror(errno));
+    continue;
+    }
+
+  if ((statbuf.st_mode & S_IFMT) != S_IFDIR)
+    {
+    DEBUG(D_transport)
+      debug_printf("skipping %s/%s: not a directory\n", s, name);
+    continue;
+    }
+
+  /* Keep the latest timestamp encountered */
+
+  if (statbuf.st_mtime > *latest) *latest = statbuf.st_mtime;
+
+  /* If this is a maildir folder, call this function recursively. */
+
+  if (name[0] == '.')
+    sum += maildir_compute_size(s, filecount, latest, regex, dir_regex,
+      timestamp_only);
+
+  /* Otherwise it must be a folder that contains messages (e.g. new or cur), so
+  we need to get its size, unless all we are interested in is the timestamp. */
+
+  else if (!timestamp_only)
+    sum += check_dir_size(s, filecount, regex);
+  }
+
+closedir(dir);
+DEBUG(D_transport)
+  {
+  if (timestamp_only)
+    debug_printf("maildir_compute_size (timestamp_only): %ld\n",
+    (long int) *latest);
+  else
+    debug_printf("maildir_compute_size: path=%s\n  sum=" OFF_T_FMT
+      " filecount=%d timestamp=%ld\n",
+      path, sum, *filecount, (long int) *latest);
+  }
+return sum;
+}
+
+
+
+/*************************************************
+*        Create or update maildirsizefile        *
+*************************************************/
+
+/* This function is called before a delivery if the option to use
+maildirsizefile is enabled. Its function is to create the file if it does not
+exist, or to update it if that is necessary.
+
+The logic in this function follows the rules that are described in
+
+  http://www.inter7.com/courierimap/README.maildirquota.html
+
+Or, at least, it is supposed to!
+
+Arguments:
+  path             the path to the maildir directory; this is already backed-up
+                     to the parent if the delivery directory is a maildirfolder
+  ob               the appendfile options block
+  regex            a compiled regex for getting a file's size from its name
+  dir_regex        a compiled regex for selecting maildir directories
+  returned_size    where to return the current size of the maildir, even if
+                     the maildirsizefile is removed because of a race
+
+Returns:           >=0  a file descriptor for an open maildirsize file
+                   -1   there was an error opening or accessing the file
+                   -2   the file was removed because of a race
+*/
+
+int
+maildir_ensure_sizefile(uschar *path, appendfile_transport_options_block *ob,
+  const pcre2_code *regex, const pcre2_code *dir_regex, off_t *returned_size,
+  int *returned_filecount)
+{
+int count, fd;
+off_t cached_quota = 0;
+int cached_quota_filecount = 0;
+int filecount = 0;
+int linecount = 0;
+off_t size = 0;
+uschar *filename;
+uschar buffer[MAX_FILE_SIZE];
+uschar *ptr = buffer;
+uschar *endptr;
+
+/* Try a few times to open or create the file, in case another process is doing
+the same thing. */
+
+filename = string_sprintf("%s/maildirsize", path);
+
+DEBUG(D_transport) debug_printf("looking for maildirsize in %s\n", path);
+if ((fd = Uopen(filename, O_RDWR|O_APPEND, ob->mode ? ob->mode : 0600)) < 0)
+  {
+  if (errno != ENOENT) return -1;
+  DEBUG(D_transport)
+    debug_printf("%s does not exist: recalculating\n", filename);
+  goto RECALCULATE;
+  }
+
+/* The file has been successfully opened. Check that the cached quota value is
+still correct, and that the size of the file is still small enough. If so,
+compute the maildir size from the file. */
+
+if ((count = read(fd, buffer, sizeof(buffer))) >= sizeof(buffer))
+  {
+  DEBUG(D_transport)
+    debug_printf("maildirsize file too big (%d): recalculating\n", count);
+  goto RECALCULATE;
+  }
+buffer[count] = 0;   /* Ensure string terminated */
+
+/* Read the quota parameters from the first line of the data. */
+
+DEBUG(D_transport)
+  debug_printf("reading quota parameters from maildirsize data\n");
+
+for (;;)
+  {
+  off_t n = (off_t)Ustrtod(ptr, &endptr);
+
+  /* Only two data items are currently defined; ignore any others that
+  may be present. The spec is for a number followed by a letter. Anything
+  else we reject and recalculate. */
+
+  if (*endptr == 'S') cached_quota = n;
+    else if (*endptr == 'C') cached_quota_filecount = (int)n;
+  if (!isalpha(*endptr++))
+    {
+    DEBUG(D_transport)
+      debug_printf("quota parameter number not followed by letter in "
+        "\"%.*s\": recalculating maildirsize\n", (int)(endptr - buffer),
+        buffer);
+    goto RECALCULATE;
+    }
+  if (*endptr == '\n' || *endptr == 0) break;
+  if (*endptr++ != ',')
+    {
+    DEBUG(D_transport)
+      debug_printf("quota parameter not followed by comma in "
+        "\"%.*s\": recalculating maildirsize\n", (int)(endptr - buffer),
+        buffer);
+    goto RECALCULATE;
+    }
+  ptr = endptr;
+  }
+
+/* Check the cached values against the current settings */
+
+if (cached_quota != ob->quota_value ||
+    cached_quota_filecount != ob->quota_filecount_value)
+  {
+  DEBUG(D_transport)
+    debug_printf("cached quota is out of date: recalculating\n"
+      "  quota=" OFF_T_FMT " cached_quota=" OFF_T_FMT " filecount_quota=%d "
+      "cached_quota_filecount=%d\n", ob->quota_value,
+      cached_quota, ob->quota_filecount_value, cached_quota_filecount);
+  goto RECALCULATE;
+  }
+
+/* Quota values agree; parse the rest of the data to get the sizes. At this
+stage, *endptr points either to 0 or to '\n'.  */
+
+DEBUG(D_transport)
+  debug_printf("computing maildir size from maildirsize data\n");
+
+while (*endptr++ == '\n')
+  {
+  if (*endptr == 0) break;
+  linecount++;
+  ptr = endptr;
+  size += (off_t)Ustrtod(ptr, &endptr);
+  if (*endptr != ' ') break;
+  ptr = endptr + 1;
+  filecount += Ustrtol(ptr, &endptr, 10);
+  }
+
+/* If *endptr is zero, we have successfully parsed the file, and we now have
+the size of the mailbox as cached in the file. The "rules" say that if this
+value indicates that the mailbox is over quota, we must recalculate if there is
+more than one entry in the file, or if the file is older than 15 minutes. Also,
+just in case there are weird values in the file, recalculate if either of the
+values is negative. */
+
+if (*endptr == 0)
+  {
+  if (size < 0 || filecount < 0)
+    {
+    DEBUG(D_transport) debug_printf("negative value in maildirsize "
+      "(size=" OFF_T_FMT " count=%d): recalculating\n", size, filecount);
+    goto RECALCULATE;
+    }
+
+  if (ob->quota_value > 0 &&
+      (size + (ob->quota_is_inclusive? message_size : 0) > ob->quota_value ||
+        (ob->quota_filecount_value > 0 &&
+          filecount + (ob->quota_is_inclusive ? 1:0) >
+            ob->quota_filecount_value)
+      ))
+    {
+    struct stat statbuf;
+    if (linecount > 1)
+      {
+      DEBUG(D_transport) debug_printf("over quota and maildirsize has "
+        "more than 1 entry: recalculating\n");
+      goto RECALCULATE;
+      }
+
+    if (fstat(fd, &statbuf) < 0) goto RECALCULATE;  /* Should never occur */
+
+    if (time(NULL) - statbuf.st_mtime > 15*60)
+      {
+      DEBUG(D_transport) debug_printf("over quota and maildirsize is older "
+        "than 15 minutes: recalculating\n");
+      goto RECALCULATE;
+      }
+    }
+  }
+
+
+/* If *endptr is not zero, there was a syntax error in the file. */
+
+else
+  {
+  int len;
+  time_t old_latest, new_latest;
+  uschar *tempname;
+  struct timeval tv;
+
+  DEBUG(D_transport)
+    {
+    uschar *p = endptr;
+    while (p > buffer && p[-1] != '\n') p--;
+    endptr[1] = 0;
+
+    debug_printf("error in maildirsizefile: unexpected character %d in "
+      "line %d (starting '%s'): recalculating\n",
+      *endptr, linecount + 1, string_printing(p));
+    }
+
+  /* Either there is no file, or the quota value has changed, or the file has
+  got too big, or there was some format error in the file. Recalculate the size
+  and write new contents to a temporary file; then rename it. After any
+  error, just return -1 as the file descriptor. */
+
+  RECALCULATE:
+
+  if (fd >= 0) (void)close(fd);
+  old_latest = 0;
+  filecount = 0;
+  size = maildir_compute_size(path, &filecount, &old_latest, regex, dir_regex,
+    FALSE);
+
+  (void)gettimeofday(&tv, NULL);
+  tempname = string_sprintf("%s/tmp/" TIME_T_FMT ".H%luP%lu.%s",
+    path, tv.tv_sec, tv.tv_usec, (long unsigned) getpid(), primary_hostname);
+
+  fd = Uopen(tempname, O_RDWR|O_CREAT|O_EXCL, ob->mode ? ob->mode : 0600);
+  if (fd >= 0)
+    {
+    (void)sprintf(CS buffer, OFF_T_FMT "S,%dC\n" OFF_T_FMT " %d\n",
+      ob->quota_value, ob->quota_filecount_value, size, filecount);
+    len = Ustrlen(buffer);
+    if (write(fd, buffer, len) != len || Urename(tempname, filename) < 0)
+      {
+      (void)close(fd);
+      fd = -1;
+      }
+    }
+
+  /* If any of the directories have been modified since the last timestamp we
+  saw, we have to junk this maildirsize file. */
+
+  DEBUG(D_transport) debug_printf("checking subdirectory timestamps\n");
+  new_latest = 0;
+  (void)maildir_compute_size(path, NULL, &new_latest , NULL, dir_regex, TRUE);
+  if (new_latest > old_latest)
+    {
+    DEBUG(D_transport) debug_printf("abandoning maildirsize because of "
+      "a later subdirectory modification\n");
+    (void)Uunlink(filename);
+    (void)close(fd);
+    fd = -2;
+    }
+  }
+
+/* Return the sizes and the file descriptor, if any */
+
+DEBUG(D_transport) debug_printf("returning maildir size=" OFF_T_FMT
+  " filecount=%d\n", size, filecount);
+*returned_size = size;
+*returned_filecount = filecount;
+return fd;
+}
+
+/* End of tf_maildir.c */