int tdb_mutex_munmap(struct tdb_context *tdb)
{
size_t len;
len = tdb_mutex_size(tdb);
if (len == 0) {
return 0;
}
return munmap(tdb->mutexes, len);
}
int tdb_mutex_munmap(struct tdb_context *tdb)
{
size_t len;
int ret;
len = tdb_mutex_size(tdb);
if (len == 0) {
return 0;
}
ret = munmap(tdb->mutexes, len);
if (ret == -1) {
return -1;
}
tdb->mutexes = NULL;
return 0;
}
int tdb_mutex_mmap(struct tdb_context *tdb)
{
size_t len;
void *ptr;
len = tdb_mutex_size(tdb);
if (len == 0) {
return 0;
}
ptr = mmap(NULL, len, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_FILE,
tdb->fd, 0);
if (ptr == MAP_FAILED) {
return -1;
}
tdb->mutexes = (struct tdb_mutexes *)ptr;
return 0;
}
/* initialise a new database with a specified hash size */
static int tdb_new_database(struct tdb_context *tdb, struct tdb_header *header,
int hash_size)
{
struct tdb_header *newdb;
size_t size;
int ret = -1;
/* We make it up in memory, then write it out if not internal */
size = sizeof(struct tdb_header) + (hash_size+1)*sizeof(tdb_off_t);
if (!(newdb = (struct tdb_header *)calloc(size, 1))) {
tdb->ecode = TDB_ERR_OOM;
return -1;
}
/* Fill in the header */
newdb->version = TDB_VERSION;
newdb->hash_size = hash_size;
tdb_header_hash(tdb, &newdb->magic1_hash, &newdb->magic2_hash);
/* Make sure older tdbs (which don't check the magic hash fields)
* will refuse to open this TDB. */
if (tdb->flags & TDB_INCOMPATIBLE_HASH)
newdb->rwlocks = TDB_HASH_RWLOCK_MAGIC;
/*
* We create a tdb with TDB_FEATURE_FLAG_MUTEX support,
* the flag combination and runtime feature checks
* are done by the caller already.
*/
if (tdb->flags & TDB_MUTEX_LOCKING) {
newdb->feature_flags |= TDB_FEATURE_FLAG_MUTEX;
}
/*
* If we have any features we add the FEATURE_FLAG_MAGIC, overwriting the
* TDB_HASH_RWLOCK_MAGIC above.
*/
if (newdb->feature_flags != 0) {
newdb->rwlocks = TDB_FEATURE_FLAG_MAGIC;
}
/*
* It's required for some following code pathes
* to have the fields on 'tdb' up-to-date.
*
* E.g. tdb_mutex_size() requires it
*/
tdb->feature_flags = newdb->feature_flags;
tdb->hash_size = newdb->hash_size;
if (tdb->flags & TDB_INTERNAL) {
tdb->map_size = size;
tdb->map_ptr = (char *)newdb;
memcpy(header, newdb, sizeof(*header));
/* Convert the `ondisk' version if asked. */
CONVERT(*newdb);
return 0;
}
if (lseek(tdb->fd, 0, SEEK_SET) == -1)
goto fail;
if (ftruncate(tdb->fd, 0) == -1)
goto fail;
if (newdb->feature_flags & TDB_FEATURE_FLAG_MUTEX) {
newdb->mutex_size = tdb_mutex_size(tdb);
tdb->hdr_ofs = newdb->mutex_size;
}
/* This creates an endian-converted header, as if read from disk */
CONVERT(*newdb);
memcpy(header, newdb, sizeof(*header));
/* Don't endian-convert the magic food! */
memcpy(newdb->magic_food, TDB_MAGIC_FOOD, strlen(TDB_MAGIC_FOOD)+1);
if (!tdb_write_all(tdb->fd, newdb, size))
goto fail;
if (newdb->feature_flags & TDB_FEATURE_FLAG_MUTEX) {
/*
* Now we init the mutex area
* followed by a second header.
*/
ret = ftruncate(
tdb->fd,
newdb->mutex_size + sizeof(struct tdb_header));
if (ret == -1) {
goto fail;
}
ret = tdb_mutex_init(tdb);
if (ret == -1) {
goto fail;
}
/*
* Write a second header behind the mutexes. That's the area
* that will be mmapp'ed.
*/
ret = lseek(tdb->fd, newdb->mutex_size, SEEK_SET);
if (ret == -1) {
goto fail;
}
if (!tdb_write_all(tdb->fd, newdb, size)) {
goto fail;
}
}
ret = 0;
fail:
SAFE_FREE(newdb);
return ret;
}
static bool tdb_mutex_open_ok(struct tdb_context *tdb,
const struct tdb_header *header)
{
int locked;
locked = tdb_nest_lock(tdb, ACTIVE_LOCK, F_WRLCK,
TDB_LOCK_NOWAIT|TDB_LOCK_PROBE);
if ((locked == -1) && (tdb->ecode == TDB_ERR_LOCK)) {
/*
* CLEAR_IF_FIRST still active. The tdb was created on this
* host, so we can assume the mutex implementation is
* compatible. Important for tools like tdbdump on a still
* open locking.tdb.
*/
goto check_local_settings;
}
/*
* We got the CLEAR_IF_FIRST lock. That means the database was
* potentially copied from somewhere else. The mutex implementation
* might be incompatible.
*/
if (tdb_nest_unlock(tdb, ACTIVE_LOCK, F_WRLCK, false) == -1) {
/*
* Should not happen
*/
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_mutex_open_ok: "
"failed to release ACTIVE_LOCK on %s: %s\n",
tdb->name, strerror(errno)));
return false;
}
if (tdb->flags & TDB_NOLOCK) {
/*
* We don't look at locks, so it does not matter to have a
* compatible mutex implementation. Allow the open.
*/
return true;
}
check_local_settings:
if (!(tdb->flags & TDB_MUTEX_LOCKING)) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_mutex_open_ok[%s]: "
"Can use mutexes only with "
"MUTEX_LOCKING or NOLOCK\n",
tdb->name));
return false;
}
if (tdb_mutex_size(tdb) != header->mutex_size) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_mutex_open_ok[%s]: "
"Mutex size changed from %u to %u\n.",
tdb->name,
(unsigned int)header->mutex_size,
(unsigned int)tdb_mutex_size(tdb)));
return false;
}
return true;
}
