* 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:
+ exim_lockfile_needed facilities predicate
+ dbfn_open_path full pathname; no lock taken, readonly
+ dbfn_open takes lockfile or opens transaction
+ dbfn_open_multi only if transactions supported;
+ no lock or transaction taken
+ dbfn_close release lockfile or transaction
+ dbfn_close_multi
+ dbfn_transaction_start only if transactions supported
+ dbfn_transaction_commit
+ dbfn_read_klen explicit key length; embedded NUL ok
+ 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
+ DBM lookup type
+*/
* Open and lock a database file *
*************************************************/
-/* Used for accessing Exim's hints databases.
-
-Arguments:
- name The single-component name of one of Exim's database files.
- flags Either O_RDONLY or O_RDWR, indicating the type of open required;
- O_RDWR implies "create if necessary"
- dbblock Points to an open_db block to be filled in.
- lof If TRUE, write to the log for actual open failures (locking failures
- are always logged).
- panic If TRUE, panic on failure to create the db directory
-
-Returns: NULL if the open failed, or the locking failed. After locking
- failures, errno is zero.
+/* Used by DBM lookups:
+full pathname for DB file rather than hintsdb name, readonly, no locking. */
- On success, dbblock is returned. This contains the dbm pointer and
- the fd of the locked lock file.
+open_db *
+dbfn_open_path(const uschar * path, open_db * dbblock)
+{
+uschar * dirname = string_copy(path);
+
+dbblock->readonly = TRUE;
+dbblock->lockfd = -1;
+dbblock->dbptr = !exim_lockfile_needed()
+ ? exim_dbopen_multi(path, dirname, O_RDONLY, 0)
+ : exim_dbopen(path, dirname, O_RDONLY, 0);
+return dbblock->dbptr ? dbblock : NULL;;
+}
-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.
-*/
+/* Ensure the directory for the DB is present */
-open_db *
-dbfn_open(uschar *name, int flags, open_db *dbblock, BOOL lof, BOOL panic)
+static inline void
+db_dir_make(BOOL panic)
{
-int rc, save_errno;
-BOOL read_only = flags == O_RDONLY;
-flock_t lock_data;
-uschar dirname[PATHLEN], filename[PATHLEN];
+(void) directory_make(spool_directory, US"db", EXIMDB_DIRECTORY_MODE, panic);
+}
-DEBUG(D_hints_lookup) acl_level++;
-/* The first thing to do is to open a separate file on which to lock. This
-ensures that Exim has exclusive use of the database before it even tries to
-open it. Early versions tried to lock on the open database itself, but that
-gave rise to mysterious problems from time to time - it was suspected that some
-DB libraries "do things" on their open() calls which break the interlocking.
-The lock file is never written to, but we open it for writing so we can get a
-write lock if required. If it does not exist, we create it. This is done
-separately so we know when we have done it, because when running as root we
-need to change the ownership - see the bottom of this function. We also try to
-make the directory as well, just in case. We won't be doing this many times
-unnecessarily, because usually the lock file will be there. If the directory
-exists, there is no error. */
+/* Lock a file to protect the DB. Return TRUE for success */
-snprintf(CS dirname, sizeof(dirname), "%s/db", spool_directory);
-snprintf(CS filename, sizeof(filename), "%s/%s.lockfile", dirname, name);
+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 ((dbblock->lockfd = Uopen(filename, O_RDWR, EXIMDB_LOCKFILE_MODE)) < 0)
+if ((*fdp = 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);
+ db_dir_make(panic);
+ *fdp = Uopen(filename, O_RDWR|O_CREAT, EXIMDB_LOCKFILE_MODE);
}
priv_restore();
-if (dbblock->lockfd < 0)
+if (*fdp < 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;
+ 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 = read_only? F_RDLCK : F_WRLCK;
+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)
sigalrm_seen = FALSE;
ALARM(EXIMDB_LOCK_TIMEOUT);
-rc = fcntl(dbblock->lockfd, F_SETLKW, &lock_data);
+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",
- read_only ? "read" : "write", filename,
+ rdonly ? "read" : "write", filename,
errno == ETIMEDOUT ? "timed out" : strerror(errno));
- (void)close(dbblock->lockfd);
+ (void)close(*fdp); *fdp = -1;
errno = 0; /* Indicates locking failure */
- DEBUG(D_hints_lookup) acl_level--;
- return NULL;
+ return FALSE;
}
DEBUG(D_hints_lookup) debug_printf_indent("locked %s\n", filename);
+return TRUE;
+}
+
+/* Used for accessing Exim's hints databases.
+
+Arguments:
+ name The single-component name of one of Exim's database files.
+ flags Either O_RDONLY or O_RDWR, indicating the type of open required;
+ optionally O_CREAT
+ dbblock Points to an open_db block to be filled in.
+ lof If TRUE, write to the log for actual open failures (locking failures
+ are always logged).
+ panic If TRUE, panic on failure to create the db directory
+
+Returns: NULL if the open failed, or the locking failed. After locking
+ failures, errno is zero.
+
+ On success, dbblock is returned. This contains the dbm pointer and
+ the fd of the locked lock file.
+*/
+
+open_db *
+dbfn_open(const uschar * name, int flags, open_db * dbblock,
+ BOOL lof, BOOL panic)
+{
+int rc, save_errno, dlen, flen;
+flock_t lock_data;
+uschar dirname[PATHLEN], filename[PATHLEN];
+
+DEBUG(D_hints_lookup) acl_level++;
+
+/* The first thing to do is to open a separate file on which to lock. This
+ensures that Exim has exclusive use of the database before it even tries to
+open it. Early versions tried to lock on the open database itself, but that
+gave rise to mysterious problems from time to time - it was suspected that some
+DB libraries "do things" on their open() calls which break the interlocking.
+The lock file is never written to, but we open it for writing so we can get a
+write lock if required. If it does not exist, we create it. This is done
+separately so we know when we have done it, because when running as root we
+need to change the ownership - see the bottom of this function. We also try to
+make the directory as well, just in case. We won't be doing this many times
+unnecessarily, because usually the lock file will be there. If the directory
+exists, there is no error. */
+
+dlen = snprintf(CS dirname, sizeof(dirname), "%s/db", spool_directory);
+
+dbblock->readonly = (flags & O_ACCMODE) == O_RDONLY;
+dbblock->lockfd = -1;
+if (!exim_lockfile_needed())
+ db_dir_make(panic);
+else
+ {
+ flen = Ustrlen(name);
+ snprintf(CS filename, sizeof(filename), "%.*s/%.*s.lockfile",
+ (int)sizeof(filename) - dlen - flen - 11, dirname,
+ flen, name);
+ if (!lockfile_take(dbblock, filename, flags == O_RDONLY, panic))
+ {
+ DEBUG(D_hints_lookup) acl_level--;
+ return NULL;
+ }
+ }
/* 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
it easy to pin this down, there are now debug statements on either side of the
open call. */
-snprintf(CS filename, sizeof(filename), "%s/%s", dirname, name);
+snprintf(CS filename, sizeof(filename), "%.*s/%s", dlen, dirname, name);
priv_drop_temp(exim_uid, exim_gid);
-dbblock->dbptr = exim_dbopen(filename, dirname, flags, EXIMDB_MODE);
-if (!dbblock->dbptr && errno == ENOENT && flags == O_RDWR)
+dbblock->dbptr = dbblock->readonly && !exim_lockfile_needed()
+ ? exim_dbopen_multi(filename, dirname, flags & O_ACCMODE, EXIMDB_MODE)
+ : exim_dbopen(filename, dirname, flags & O_ACCMODE, EXIMDB_MODE);
+
+if (!dbblock->dbptr && errno == ENOENT && flags & O_CREAT)
{
DEBUG(D_hints_lookup)
debug_printf_indent("%s appears not to exist: trying to create\n", filename);
- dbblock->dbptr = exim_dbopen(filename, dirname, flags|O_CREAT, EXIMDB_MODE);
+ dbblock->dbptr = exim_dbopen(filename, dirname, flags, EXIMDB_MODE);
}
save_errno = errno;
priv_restore();
debug_printf_indent("%s\n", CS string_open_failed("DB file %s",
filename));
(void)close(dbblock->lockfd);
- errno = save_errno;
- DEBUG(D_hints_lookup) acl_level--;
- return NULL;
+ dbblock->lockfd = -1;
+ dbblock = NULL;
}
-DEBUG(D_hints_lookup)
- 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
for the lock. */
+DEBUG(D_hints_lookup) acl_level--;
+return dbblock;
+}
+
+
+
+/* Only for transaction-capable DB types. Open without locking or
+starting a transaction. "lof" and "panic" always true; read/write mode.
+*/
+
+open_db *
+dbfn_open_multi(const uschar * name, int flags, open_db * dbblock)
+{
+int rc, save_errno, dlen;
+flock_t lock_data;
+uschar dirname[PATHLEN], filename[PATHLEN];
+
+DEBUG(D_hints_lookup) acl_level++;
+
+dbblock->lockfd = -1;
+dbblock->readonly = (flags & O_ACCMODE) == O_RDONLY;
+db_dir_make(TRUE);
+
+dlen = snprintf(CS dirname, sizeof(dirname), "%s/db", spool_directory);
+snprintf(CS filename, sizeof(filename), "%.*s/%s", dlen, dirname, name);
+
+priv_drop_temp(exim_uid, exim_gid);
+dbblock->dbptr = exim_dbopen_multi(filename, dirname, flags & O_ACCMODE, EXIMDB_MODE);
+if (!dbblock->dbptr && errno == ENOENT && flags & O_CREAT)
+ {
+ DEBUG(D_hints_lookup)
+ debug_printf_indent("%s appears not to exist: trying to create\n", filename);
+ dbblock->dbptr = exim_dbopen_multi(filename, dirname, flags, EXIMDB_MODE);
+ }
+save_errno = errno;
+priv_restore();
+
+/* If the open has failed, return NULL, leaving errno set. If lof is TRUE,
+log the event - also for debugging - but debug only if the file just doesn't
+exist. */
+
+if (!dbblock->dbptr)
+ {
+ errno = save_errno;
+ if (save_errno != ENOENT)
+ log_write(0, LOG_MAIN, "%s", string_open_failed("DB file %s",
+ filename));
+ else
+ DEBUG(D_hints_lookup)
+ debug_printf_indent("%s\n", CS string_open_failed("DB file %s",
+ filename));
+ dbblock = NULL;
+ }
+
+/* Pass back the block containing the opened database handle */
+DEBUG(D_hints_lookup) acl_level--;
return dbblock;
}
+/* Return: boolean success */
+BOOL
+dbfn_transaction_start(open_db * dbp)
+{
+DEBUG(D_hints_lookup) debug_printf_indent("dbfn_transaction_start\n");
+if (!dbp->readonly) return exim_dbtransaction_start(dbp->dbptr);
+return FALSE;
+}
+void
+dbfn_transaction_commit(open_db * dbp)
+{
+DEBUG(D_hints_lookup) debug_printf_indent("dbfn_transaction_commit\n");
+if (!dbp->readonly) exim_dbtransaction_commit(dbp->dbptr);
+}
+
/*************************************************
*************************************************/
/* 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)
+dbfn_close(open_db * dbp)
+{
+int * fdp = &dbp->lockfd;
+
+if (dbp->readonly && !exim_lockfile_needed())
+ exim_dbclose_multi(dbp->dbptr);
+else
+ exim_dbclose(dbp->dbptr);
+
+if (*fdp >= 0) (void)close(*fdp);
+DEBUG(D_hints_lookup)
+ debug_printf_indent("closed hints database%s\n",
+ *fdp < 0 ? "" : " and lockfile");
+*fdp = -1;
+}
+
+
+void
+dbfn_close_multi(open_db * dbp)
{
-exim_dbclose(dbblock->dbptr);
-(void)close(dbblock->lockfd);
+exim_dbclose_multi(dbp->dbptr);
DEBUG(D_hints_lookup)
- { debug_printf_indent("closed hints database and lockfile\n"); acl_level--; }
+ debug_printf_indent("closed hints database\n");
}
* Read from database file *
*************************************************/
-/* Passing back the pointer unchanged is useless, because there is
+/* Read, using a defined-length key (permitting embedded NULs).
+
+Passing back the pointer unchanged is useless, because there is
no guarantee of alignment. Since all the records used by Exim need
to be properly aligned to pick out the timestamps, etc., we might as
well do the copying centrally here.
-Most calls don't need the length, so there is a macro called dbfn_read which
-has two arguments; it calls this function adding NULL as the third.
-
Arguments:
dbblock a pointer to an open database block
key the key of the record to be read
+ klen length of key including a terminating NUL (if present)
length a pointer to an int into which to return the length, if not NULL
Returns: a pointer to the retrieved record, or
*/
void *
-dbfn_read_with_length(open_db * dbblock, const uschar * key, int * length)
+dbfn_read_klen(open_db * dbblock, const uschar * key, int klen, int * length)
{
void * yield;
EXIM_DATUM key_datum, result_datum;
-int klen = Ustrlen(key) + 1;
uschar * key_copy = store_get(klen, key);
unsigned dlen;
memcpy(key_copy, key, klen);
-DEBUG(D_hints_lookup) debug_printf_indent("dbfn_read: key=%s\n", key);
+DEBUG(D_hints_lookup) debug_printf_indent("dbfn_read: key=%.*s\n", klen, key);
exim_datum_init(&key_datum); /* Some DBM libraries require the datum */
exim_datum_init(&result_datum); /* to be cleared before use. */
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);
+DEBUG(D_hints_lookup) debug_printf_indent("dbfn_read: size %u return\n", dlen);
+
+yield = store_get(dlen+1, GET_TAINTED);
memcpy(yield, exim_datum_data_get(&result_datum), dlen);
+((uschar *)yield)[dlen] = '\0';
if (length) *length = dlen;
exim_datum_free(&result_datum); /* Some DBM libs require freeing */
}
+/* Read, using a NUL-terminated key.
+
+Most calls don't need the length, so there is a macro called dbfn_read which
+has two arguments; it calls this function adding NULL as the third.
+
+Arguments:
+ dbblock a pointer to an open database block
+ key the key of the record to be read (NUL-terminated)
+ lenp a pointer to an int into which to return the data length,
+ if not NULL
+
+Returns: a pointer to the retrieved record, or
+ NULL if the record is not found
+*/
+
+void *
+dbfn_read_with_length(open_db * dbblock, const uschar * key, int * lenp)
+{
+return dbfn_read_klen(dbblock, key, Ustrlen(key)+1, lenp);
+}
+
+
+
/* Read a record. If the length is not as expected then delete it, write
an error log line, delete the record and return NULL.
Use this for fixed-size records (so not retry or wait records).
return NULL;
}
-
/*************************************************
* Write to database file *
*************************************************/
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. */
int
dbfn_delete(open_db *dbblock, const uschar *key)
{
-int klen = Ustrlen(key) + 1;
+int klen = Ustrlen(key) + 1, rc;
uschar * key_copy = store_get(klen, key);
EXIM_DATUM key_datum;
exim_datum_init(&key_datum); /* Some DBM libraries require clearing */
exim_datum_data_set(&key_datum, key_copy);
exim_datum_size_set(&key_datum, klen);
-return exim_dbdel(dbblock->dbptr, &key_datum);
+rc = exim_dbdel(dbblock->dbptr, &key_datum);
+DEBUG(D_hints_lookup) if (rc != EXIM_DBPUTB_OK)
+ debug_printf_indent(" exim_dbdel: fail\n");
+return rc;
}
+#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 /*notdef*/
{
count = Uatoi(cmd);
while (isdigit((uschar)*cmd)) cmd++;
- while (isspace((uschar)*cmd)) cmd++;
+ Uskip_whitespace(&cmd);
}
if (Ustrncmp(cmd, "open", 4) == 0)
int i;
open_db *odb;
uschar *s = cmd + 4;
- while (isspace((uschar)*s)) s++;
+ Uskip_whitespace(&s);
for (i = 0; i < max_db; i++)
if (dbblock[i].dbptr == NULL) break;
}
start = clock();
- odb = dbfn_open(s, O_RDWR, dbblock + i, TRUE, TRUE);
+ odb = dbfn_open(s, O_RDWR|O_CREAT, dbblock + i, TRUE, TRUE);
stop = clock();
if (odb)
else if (Ustrncmp(cmd, "write", 5) == 0)
{
int rc = 0;
- uschar *key = cmd + 5;
- uschar *data;
+ uschar * key = cmd + 5, * data;
if (current < 0)
{
continue;
}
- while (isspace((uschar)*key)) key++;
+ Uskip_whitespace(&key);
data = key;
- while (*data != 0 && !isspace((uschar)*data)) data++;
- *data++ = 0;
- while (isspace((uschar)*data)) data++;
+ Uskip_nonwhite(&data);
+ *data++ = '\0';
+ Uskip_whitespace(&data);
dbwait = (dbdata_wait *)(&structbuffer);
Ustrcpy(dbwait->text, data);
else if (Ustrncmp(cmd, "read", 4) == 0)
{
- uschar *key = cmd + 4;
+ uschar * key = cmd + 4;
if (current < 0)
{
printf("No current database\n");
continue;
}
- while (isspace((uschar)*key)) key++;
+ Uskip_whitespace(&key);
start = clock();
while (count-- > 0)
dbwait = (dbdata_wait *)dbfn_read_with_length(dbblock+ current, key, NULL);
else if (Ustrncmp(cmd, "delete", 6) == 0)
{
- uschar *key = cmd + 6;
+ uschar * key = cmd + 6;
if (current < 0)
{
printf("No current database\n");
continue;
}
- while (isspace((uschar)*key)) key++;
+ Uskip_whitespace(&key);
dbfn_delete(dbblock + current, key);
}
else if (Ustrncmp(cmd, "close", 5) == 0)
{
- uschar *s = cmd + 5;
- while (isspace((uschar)*s)) s++;
+ uschar * s = cmd + 5;
+ Uskip_whitespace(&s);
i = Uatoi(s);
if (i >= max_db || dbblock[i].dbptr == NULL) printf("Not open\n"); else
{
else if (Ustrncmp(cmd, "file", 4) == 0)
{
- uschar *s = cmd + 4;
- while (isspace((uschar)*s)) s++;
+ uschar * s = cmd + 4;
+ Uskip_whitespace(&s);
i = Uatoi(s);
if (i >= max_db || dbblock[i].dbptr == NULL) printf("Not open\n");
else current = i;
#endif
/* End of dbfn.c */
+/* vi: aw ai sw=2
+*/
git://git.exim.org / exim.git / blobdiff