summaryrefslogtreecommitdiffstats
path: root/src/transports/tf_maildir.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/transports/tf_maildir.c')
-rw-r--r--src/transports/tf_maildir.c585
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 */
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-03 12:20:11 +0000