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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 16:16:13 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 16:16:13 +0000 |
commit | e90fcc54809db2591dc083f43ef54c6ec8c60847 (patch) | |
tree | f20bc206c3c2d5d59d37c46c5cf5d53a20642556 /src/transports/tf_maildir.c | |
parent | Initial commit. (diff) | |
download | exim4-e90fcc54809db2591dc083f43ef54c6ec8c60847.tar.xz exim4-e90fcc54809db2591dc083f43ef54c6ec8c60847.zip |
Adding upstream version 4.96.upstream/4.96upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | src/transports/tf_maildir.c | 585 |
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 */ |