* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) The Exim Maintainers 2020 - 2022 */
+/* Copyright (c) The Exim Maintainers 2020 - 2024 */
/* Copyright (c) University of Cambridge 1995 - 2018 */
/* See the file NOTICE for conditions of use and distribution. */
/* SPDX-License-Identifier: GPL-2.0-or-later */
different DBM files. This module does not contain code for reading DBM files
for (e.g.) alias expansion. That is all contained within the general search
functions. As Exim now has support for several DBM interfaces, all the relevant
-functions are called as macros.
+functions are called as inlinable functions from an included file.
All the data in Exim's database is in the nature of *hints*. Therefore it
doesn't matter if it gets destroyed by accident. These functions are not
DBM files themselves were never completely successful.) Since callers may in
general want to do more than one read or write while holding the lock, there
are separate open and close functions. However, the calling modules should
-arrange to hold the locks for the bare minimum of time. */
+arrange to hold the locks for the bare minimum of time.
+
+API:
+ dbfn_open
+ dbfn_close
+ dbfn_read_with_length
+ dbfn_read_enforce_length
+ dbfn_write
+ dbfn_delete
+ dbfn_scan unused; ifdeffout out
+
+Users:
+ ACL ratelimit & seen conditions
+ delivery retry handling
+ delivery serialization
+ TLS session resumption
+ peer capability cache
+ callout & quota cache
+*/
* Open and lock a database file *
*************************************************/
+/* Ensure the directory for the DB is present */
+
+static inline void
+db_dir_make(BOOL panic)
+{
+(void) directory_make(spool_directory, US"db", EXIMDB_DIRECTORY_MODE, panic);
+}
+
+
+/* Lock a file to protect the DB. Return TRUE for success */
+
+static inline BOOL
+lockfile_take(open_db * dbblock, const uschar * filename, BOOL rdonly, BOOL panic)
+{
+flock_t lock_data;
+int rc, * fdp = &dbblock->lockfd;
+
+priv_drop_temp(exim_uid, exim_gid);
+if ((*fdp = Uopen(filename, O_RDWR, EXIMDB_LOCKFILE_MODE)) < 0)
+ {
+ db_dir_make(panic);
+ *fdp = Uopen(filename, O_RDWR|O_CREAT, EXIMDB_LOCKFILE_MODE);
+ }
+priv_restore();
+
+if (*fdp < 0)
+ {
+ log_write(0, LOG_MAIN, "%s",
+ string_open_failed("database lock file %s", filename));
+ errno = 0; /* Indicates locking failure */
+ return FALSE;
+ }
+
+/* Now we must get a lock on the opened lock file; do this with a blocking
+lock that times out. */
+
+lock_data.l_type = rdonly ? F_RDLCK : F_WRLCK;
+lock_data.l_whence = lock_data.l_start = lock_data.l_len = 0;
+
+DEBUG(D_hints_lookup|D_retry|D_route|D_deliver)
+ debug_printf_indent("locking %s\n", filename);
+
+sigalrm_seen = FALSE;
+ALARM(EXIMDB_LOCK_TIMEOUT);
+rc = fcntl(*fdp, F_SETLKW, &lock_data);
+ALARM_CLR(0);
+
+if (sigalrm_seen) errno = ETIMEDOUT;
+if (rc < 0)
+ {
+ log_write(0, LOG_MAIN|LOG_PANIC, "Failed to get %s lock for %s: %s",
+ rdonly ? "read" : "write", filename,
+ errno == ETIMEDOUT ? "timed out" : strerror(errno));
+ (void)close(*fdp); *fdp = -1;
+ errno = 0; /* Indicates locking failure */
+ return FALSE;
+ }
+
+DEBUG(D_hints_lookup) debug_printf_indent("locked %s\n", filename);
+return TRUE;
+}
+
/* Used for accessing Exim's hints databases.
Arguments:
On success, dbblock is returned. This contains the dbm pointer and
the fd of the locked lock file.
-
-There are some calls that use O_RDWR|O_CREAT for the flags. Having discovered
-this in December 2005, I'm not sure if this is correct or not, but for the
-moment I haven't changed them.
*/
open_db *
-dbfn_open(uschar *name, int flags, open_db *dbblock, BOOL lof, BOOL panic)
+dbfn_open(const uschar * name, int flags, open_db * dbblock,
+ BOOL lof, BOOL panic)
{
int rc, save_errno;
-BOOL read_only = flags == O_RDONLY;
flock_t lock_data;
uschar dirname[PATHLEN], filename[PATHLEN];
snprintf(CS dirname, sizeof(dirname), "%s/db", spool_directory);
snprintf(CS filename, sizeof(filename), "%s/%s.lockfile", dirname, name);
-priv_drop_temp(exim_uid, exim_gid);
-if ((dbblock->lockfd = Uopen(filename, O_RDWR, EXIMDB_LOCKFILE_MODE)) < 0)
- {
- (void)directory_make(spool_directory, US"db", EXIMDB_DIRECTORY_MODE, panic);
- dbblock->lockfd = Uopen(filename, O_RDWR|O_CREAT, EXIMDB_LOCKFILE_MODE);
- }
-priv_restore();
-
-if (dbblock->lockfd < 0)
- {
- log_write(0, LOG_MAIN, "%s",
- string_open_failed("database lock file %s", filename));
- errno = 0; /* Indicates locking failure */
- DEBUG(D_hints_lookup) acl_level--;
- return NULL;
- }
-
-/* Now we must get a lock on the opened lock file; do this with a blocking
-lock that times out. */
-
-lock_data.l_type = read_only? F_RDLCK : F_WRLCK;
-lock_data.l_whence = lock_data.l_start = lock_data.l_len = 0;
-
-DEBUG(D_hints_lookup|D_retry|D_route|D_deliver)
- debug_printf_indent("locking %s\n", filename);
-
-sigalrm_seen = FALSE;
-ALARM(EXIMDB_LOCK_TIMEOUT);
-rc = fcntl(dbblock->lockfd, F_SETLKW, &lock_data);
-ALARM_CLR(0);
-
-if (sigalrm_seen) errno = ETIMEDOUT;
-if (rc < 0)
+dbblock->lockfd = -1;
+if (!exim_lockfile_needed())
+ db_dir_make(panic);
+else
{
- log_write(0, LOG_MAIN|LOG_PANIC, "Failed to get %s lock for %s: %s",
- read_only ? "read" : "write", filename,
- errno == ETIMEDOUT ? "timed out" : strerror(errno));
- (void)close(dbblock->lockfd);
- errno = 0; /* Indicates locking failure */
- DEBUG(D_hints_lookup) acl_level--;
- return NULL;
+ if (!lockfile_take(dbblock, filename, flags == O_RDONLY, panic))
+ {
+ DEBUG(D_hints_lookup) acl_level--;
+ return NULL;
+ }
}
-DEBUG(D_hints_lookup) debug_printf_indent("locked %s\n", filename);
-
/* At this point we have an opened and locked separate lock file, that is,
exclusive access to the database, so we can go ahead and open it. If we are
expected to create it, don't do so at first, again so that we can detect
it easy to pin this down, there are now debug statements on either side of the
open call. */
+flags &= O_RDONLY | O_RDWR;
snprintf(CS filename, sizeof(filename), "%s/%s", dirname, name);
priv_drop_temp(exim_uid, exim_gid);
debug_printf_indent("%s\n", CS string_open_failed("DB file %s",
filename));
(void)close(dbblock->lockfd);
+ dbblock->lockfd = -1;
errno = save_errno;
DEBUG(D_hints_lookup) acl_level--;
return NULL;
debug_printf_indent("opened hints database %s: flags=%s\n", filename,
flags == O_RDONLY ? "O_RDONLY"
: flags == O_RDWR ? "O_RDWR"
- : flags == (O_RDWR|O_CREAT) ? "O_RDWR|O_CREAT"
: "??");
/* Pass back the block containing the opened database handle and the open fd
*************************************************/
/* Closing a file automatically unlocks it, so after closing the database, just
-close the lock file.
+close the lock file if there was one.
Argument: a pointer to an open database block
Returns: nothing
void
dbfn_close(open_db *dbblock)
{
+int * fdp = &dbblock->lockfd;
+
exim_dbclose(dbblock->dbptr);
-(void)close(dbblock->lockfd);
+if (*fdp >= 0) (void)close(*fdp);
DEBUG(D_hints_lookup)
- { debug_printf_indent("closed hints database and lockfile\n"); acl_level--; }
+ {
+ debug_printf_indent("closed hints database%s\n",
+ *fdp < 0 ? "" : " and lockfile");
+ acl_level--;
+ }
+*fdp = -1;
}
exim_datum_data_set(&key_datum, key_copy);
exim_datum_size_set(&key_datum, klen);
-if (!exim_dbget(dbblock->dbptr, &key_datum, &result_datum)) return NULL;
+if (!exim_dbget(dbblock->dbptr, &key_datum, &result_datum))
+ {
+ DEBUG(D_hints_lookup) debug_printf_indent("dbfn_read: null return\n");
+ return NULL;
+ }
/* Assume the data store could have been tainted. Properly, we should
store the taint status with the data. */
dlen = exim_datum_size_get(&result_datum);
yield = store_get(dlen, GET_TAINTED);
memcpy(yield, exim_datum_data_get(&result_datum), dlen);
+DEBUG(D_hints_lookup) debug_printf_indent("dbfn_read: size %u return\n", dlen);
if (length) *length = dlen;
exim_datum_free(&result_datum); /* Some DBM libs require freeing */
memcpy(key_copy, key, klen);
gptr->time_stamp = time(NULL);
-DEBUG(D_hints_lookup) debug_printf_indent("dbfn_write: key=%s\n", key);
+DEBUG(D_hints_lookup)
+ debug_printf_indent("dbfn_write: key=%s datalen %d\n", key, length);
exim_datum_init(&key_datum); /* Some DBM libraries require the datum */
exim_datum_init(&value_datum); /* to be cleared before use. */
+#ifdef notdef
+/* XXX This appears to be unused. There's a separate implementation
+in dbutils.c for dumpdb and fixdb, using the same underlying support.
+*/
+
/*************************************************
* Scan the keys of a database file *
*************************************************/
if (!yield) exim_dbdelete_cursor(*cursor);
return yield;
}
+#endif
Uskip_whitespace(&key);
data = key;
- while (*data && !isspace((uschar)*data)) data++;
- *data++ = 0;
+ Uskip_nonwhite(&data);
+ *data++ = '\0';
Uskip_whitespace(&data);
dbwait = (dbdata_wait *)(&structbuffer);