isync/maildir.c
Michael Elkins c121ec912f updated year in copyright notice
the uid for each message in the maildir is now stored in a dbm database
rather than the filename.  this change was necessary because isync became
confused if you copied a message to another folder, in which case the uid
was invalid.

as a result of the above change, isync now acquires a mutex on the mailbox
to protect the dbm database from concurrent access.

main() was reworked to continue gracefully when an error is encountered, and
to always call maildir_close() so that the lock can be disabled, and the
database closed.
2002-01-16 19:47:28 +00:00

512 lines
11 KiB
C

/* $Id$
*
* isync - IMAP4 to maildir mailbox synchronizer
* Copyright (C) 2000-2 Michael R. Elkins <me@mutt.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <dirent.h>
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/stat.h>
#include <errno.h>
#include <time.h>
#include "isync.h"
static int
do_lock (int fd, int flag)
{
struct flock lck;
struct stat sb;
if (fstat (fd, &sb))
{
perror ("fstat");
return -1;
}
memset (&lck, 0, sizeof (lck));
lck.l_type = flag;
lck.l_whence = SEEK_SET;
lck.l_start = 0;
lck.l_len = sb.st_size;
if (fcntl (fd, F_SETLK, &lck))
{
perror ("fcntl");
close (fd);
return -1;
}
return 0;
}
/* 2,<flags> */
static void
parse_info (message_t * m, char *s)
{
if (*s == '2' && *(s + 1) == ',')
{
s += 2;
while (*s)
{
if (*s == 'F')
m->flags |= D_FLAGGED;
else if (*s == 'R')
m->flags |= D_ANSWERED;
else if (*s == 'T')
m->flags |= D_DELETED;
else if (*s == 'S')
m->flags |= D_SEEN;
s++;
}
}
}
static unsigned int
read_uid (const char *path, const char *file)
{
char full[_POSIX_PATH_MAX];
int fd;
int ret = 0;
int len;
char buf[64];
unsigned int uid = 0;
snprintf (full, sizeof (full), "%s/%s", path, file);
fd = open (full, O_RDONLY);
if (fd == -1)
{
if (errno != ENOENT)
{
perror (full);
return -1;
}
return 0; /* doesn't exist */
}
len = read (fd, buf, sizeof (buf) - 1);
if (len == -1)
{
perror ("read");
ret = -1;
}
else
{
buf[len] = 0;
uid = atol (buf);
}
close (fd);
return ret ? (unsigned int) ret : uid;
}
/* NOTE: this is NOT NFS safe */
static int
maildir_lock (mailbox_t * m)
{
char path[_POSIX_PATH_MAX];
snprintf (path, sizeof (path), "%s/isynclock", m->path);
m->lockfd = open (path, O_WRONLY | O_CREAT | O_EXCL, S_IWUSR | S_IRUSR);
if (m->lockfd == -1)
{
perror (path);
return -1;
}
if (do_lock (m->lockfd, F_WRLCK))
{
close (m->lockfd);
return -1;
}
return 0;
}
static void
maildir_unlock (mailbox_t * m)
{
char path[_POSIX_PATH_MAX];
snprintf (path, sizeof (path), "%s/isynclock", m->path);
unlink (path);
do_lock (m->lockfd, F_UNLCK);
close (m->lockfd);
}
/* open a maildir mailbox.
* if OPEN_FAST is set, we just check to make
* sure its a valid mailbox and don't actually parse it. any IMAP messages
* with the \Recent flag set are guaranteed not to be in the mailbox yet,
* so we can save a lot of time when the user just wants to fetch new messages
* without syncing the flags.
* if OPEN_CREATE is set, we create the mailbox if it doesn't already exist.
*/
mailbox_t *
maildir_open (const char *path, int flags)
{
char buf[_POSIX_PATH_MAX];
DIR *d;
struct dirent *e;
message_t **cur;
message_t *p;
mailbox_t *m;
char *s;
int count = 0;
struct stat sb;
const char *subdirs[] = { "cur", "new", "tmp" };
int i;
datum key;
m = calloc (1, sizeof (mailbox_t));
m->lockfd = -1;
/* filename expansion happens here, not in the config parser */
m->path = expand_strdup (path);
if (stat (m->path, &sb))
{
if (errno == ENOENT && (flags & OPEN_CREATE))
{
if (mkdir (m->path, S_IRUSR | S_IWUSR | S_IXUSR))
{
fprintf (stderr, "ERROR: mkdir %s: %s (errno %d)\n",
m->path, strerror (errno), errno);
goto err;
}
for (i = 0; i < 3; i++)
{
snprintf (buf, sizeof (buf), "%s/%s", m->path, subdirs[i]);
if (mkdir (buf, S_IRUSR | S_IWUSR | S_IXUSR))
{
fprintf (stderr, "ERROR: mkdir %s: %s (errno %d)\n",
buf, strerror (errno), errno);
goto err;
}
}
}
else
{
fprintf (stderr, "ERROR: stat %s: %s (errno %d)\n", m->path,
strerror (errno), errno);
goto err;
}
}
else
{
/* check to make sure this looks like a valid maildir box */
for (i = 0; i < 3; i++)
{
snprintf (buf, sizeof (buf), "%s/%s", m->path, subdirs[i]);
if (stat (buf, &sb))
{
fprintf (stderr, "ERROR: stat %s: %s (errno %d)\n", buf,
strerror (errno), errno);
fprintf (stderr,
"ERROR: %s does not appear to be a valid maildir style mailbox\n",
m->path);
goto err;
}
}
}
/* we need a mutex on the maildir because of the state files that isync
* uses.
*/
if (maildir_lock (m))
goto err;
/* check for the uidvalidity value */
m->uidvalidity = read_uid (m->path, "isyncuidvalidity");
if (m->uidvalidity == (unsigned int) -1)
goto err;
/* load the current maxuid */
if ((m->maxuid = read_uid (m->path, "isyncmaxuid")) == (unsigned int) -1)
goto err;
if (flags & OPEN_FAST)
return m;
snprintf (buf, sizeof (buf), "%s/isyncuidmap", m->path);
m->db = dbm_open (buf, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR);
if (m->db == NULL)
{
fputs ("ERROR: unable to open UID db\n", stderr);
goto err;
}
cur = &m->msgs;
for (; count < 2; count++)
{
/* read the msgs from the new subdir */
snprintf (buf, sizeof (buf), "%s/%s", m->path,
(count == 0) ? "new" : "cur");
d = opendir (buf);
if (!d)
{
perror ("opendir");
goto err;
}
while ((e = readdir (d)))
{
if (*e->d_name == '.')
continue; /* skip dot-files */
*cur = calloc (1, sizeof (message_t));
p = *cur;
p->file = strdup (e->d_name);
p->uid = -1;
p->flags = 0;
p->new = (count == 0);
/* determine the UID for this message. The basename (sans
* flags) is used as the key in the db
*/
strfcpy (buf, p->file, sizeof (buf));
s = strchr (p->file, ':');
if (s)
*s = 0;
key.dptr = buf;
key.dsize = strlen (buf);
key = dbm_fetch (m->db, key);
if (key.dptr)
{
p->uid = *(int *) key.dptr;
if (p->uid > m->maxuid)
m->maxuid = p->uid;
}
else
puts ("Warning, no UID for message");
if (s)
parse_info (p, s + 1);
if (p->flags & D_DELETED)
m->deleted++;
cur = &p->next;
}
closedir (d);
}
return m;
err:
if (m->db)
dbm_close (m->db);
if (m->lockfd != -1)
maildir_unlock (m);
free (m->path);
free (m);
return NULL;
}
/* permanently remove messages from a maildir mailbox. if `dead' is nonzero,
* we only remove the messags marked dead.
*/
int
maildir_expunge (mailbox_t * mbox, int dead)
{
message_t **cur = &mbox->msgs;
message_t *tmp;
char path[_POSIX_PATH_MAX];
while (*cur)
{
if ((dead == 0 && (*cur)->flags & D_DELETED) ||
(dead && (*cur)->dead))
{
tmp = *cur;
*cur = (*cur)->next;
snprintf (path, sizeof (path), "%s/%s/%s",
mbox->path, tmp->new ? "new" : "cur", tmp->file);
if (unlink (path))
perror ("unlink");
free (tmp->file);
free (tmp);
}
else
cur = &(*cur)->next;
}
return 0;
}
int
maildir_update_maxuid (mailbox_t * mbox)
{
int fd;
char buf[64];
size_t len;
unsigned int uid;
char path[_POSIX_PATH_MAX];
int ret = 0;
snprintf (path, sizeof (path), "%s/isyncmaxuid", mbox->path);
fd = open (path, O_RDWR | O_CREAT, 0600);
if (fd == -1)
{
perror ("open");
return -1;
}
/* lock the file */
if (do_lock (fd, F_WRLCK))
{
close (fd);
return -1;
}
/* read the file again just to make sure it wasn't updated while
* we were doing something else
*/
len = read (fd, buf, sizeof (buf) - 1);
buf[len] = 0;
uid = atol (buf);
if (uid > mbox->maxuid)
{
fputs ("ERROR: maxuid is now higher (fatal)\n", stderr);
ret = -1;
}
if (!ret)
{
/* rewind */
lseek (fd, 0, SEEK_SET);
/* write out the file */
snprintf (buf, sizeof (buf), "%u\n", mbox->maxuid);
len = write (fd, buf, strlen (buf));
if (len == (size_t) - 1)
{
perror ("write");
ret = -1;
}
else
{
ret = ftruncate (fd, len);
if (ret)
perror ("ftruncate");
}
}
ret |= do_lock (fd, F_UNLCK);
ret |= close (fd);
return ret;
}
#define _24_HOURS (3600 * 24)
static void
maildir_clean_tmp (const char *mbox)
{
char path[_POSIX_PATH_MAX];
DIR *dirp;
struct dirent *entry;
struct stat info;
time_t now;
snprintf (path, sizeof (path), "%s/tmp", mbox);
dirp = opendir (path);
if (dirp == NULL)
{
fprintf (stderr, "maildir_clean_tmp: opendir: %s: %s (errno %d)\n",
path, strerror (errno), errno);
return;
}
/* assuming this scan will take less than a second, we only need to
* check the time once before the following loop.
*/
time (&now);
while ((entry = readdir (dirp)))
{
snprintf (path, sizeof (path), "%s/tmp/%s", mbox, entry->d_name);
if (stat (path, &info))
fprintf (stderr, "maildir_clean_tmp: stat: %s: %s (errno %d)\n",
path, strerror (errno), errno);
else if (S_ISREG (info.st_mode) && now - info.st_ctime >= _24_HOURS)
{
/* this should happen infrequently enough that it won't be
* bothersome to the user to display when it occurs.
*/
printf ("Warning: removing stale file %s\n", path);
if (unlink (path))
fprintf (stderr,
"maildir_clean_tmp: unlink: %s: %s (errno %d)\n",
path, strerror (errno), errno);
}
}
}
void
maildir_close (mailbox_t * mbox)
{
if (mbox->db)
dbm_close (mbox->db);
/* release the mutex on the mailbox */
maildir_unlock (mbox);
/* per the maildir(5) specification, delivery agents are supposed to
* set a 24-hour timer on items placed in the `tmp' directory.
*/
maildir_clean_tmp (mbox->path);
free (mbox->path);
free_message (mbox->msgs);
memset (mbox, 0xff, sizeof (mailbox_t));
free (mbox);
}
int
maildir_set_uidvalidity (mailbox_t * mbox, unsigned int uidvalidity)
{
char path[_POSIX_PATH_MAX];
char buf[16];
int fd;
int ret;
snprintf (path, sizeof (path), "%s/isyncuidvalidity", mbox->path);
fd = open (path, O_WRONLY | O_CREAT | O_EXCL, 0600);
if (fd == -1)
{
perror ("open");
return -1;
}
snprintf (buf, sizeof (buf), "%u\n", uidvalidity);
ret = write (fd, buf, strlen (buf));
if (ret == -1)
perror ("write");
else if ((size_t) ret != strlen (buf))
ret = -1;
else
ret = 0;
if (close (fd))
{
perror ("close");
ret = -1;
}
if (ret)
if (unlink (path))
perror ("unlink");
return (ret);
}