X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Ftdb%2Fopen.c;h=aa974431db3fae958d074469c8d6e948e1d097a9;hp=1d6b3ed75ab084033723122c71857a1f8d5e84d5;hb=6a8d296f9383dd25ec381e2ab136a33823d140e5;hpb=4364f6a8e21a8f7c561f121af3a834cf7e0649ce

diff --git a/ccan/tdb/open.c b/ccan/tdb/open.c
index 1d6b3ed7..aa974431 100644
--- a/ccan/tdb/open.c
+++ b/ccan/tdb/open.c
@@ -30,20 +30,25 @@
 /* all contexts, to ensure no double-opens (fcntl locks don't nest!) */
 static struct tdb_context *tdbs = NULL;
 
-
-/* This is based on the hash algorithm from gdbm */
-static unsigned int default_tdb_hash(TDB_DATA *key)
+/* We use two hashes to double-check they're using the right hash function. */
+void tdb_header_hash(struct tdb_context *tdb,
+		     uint32_t *magic1_hash, uint32_t *magic2_hash)
 {
-	uint32_t value;	/* Used to compute the hash value.  */
-	uint32_t   i;	/* Used to cycle through random values. */
+	TDB_DATA hash_key;
+	uint32_t tdb_magic = TDB_MAGIC;
 
-	/* Set the initial value from the key size. */
-	for (value = 0x238F13AF * key->dsize, i=0; i < key->dsize; i++)
-		value = (value + (key->dptr[i] << (i*5 % 24)));
+	hash_key.dptr = (unsigned char *)TDB_MAGIC_FOOD;
+	hash_key.dsize = sizeof(TDB_MAGIC_FOOD);
+	*magic1_hash = tdb->hash_fn(&hash_key);
 
-	return (1103515243 * value + 12345);  
-}
+	hash_key.dptr = CONVERT(tdb_magic);
+	hash_key.dsize = sizeof(tdb_magic);
+	*magic2_hash = tdb->hash_fn(&hash_key);
 
+	/* Make sure at least one hash is non-zero! */
+	if (*magic1_hash == 0 && *magic2_hash == 0)
+		*magic1_hash = 1;
+}
 
 /* initialise a new database with a specified hash size */
 static int tdb_new_database(struct tdb_context *tdb, int hash_size)
@@ -63,6 +68,14 @@ static int tdb_new_database(struct tdb_context *tdb, int hash_size)
 	/* 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;
+
 	if (tdb->flags & TDB_INTERNAL) {
 		tdb->map_size = size;
 		tdb->map_ptr = (char *)newdb;
@@ -138,11 +151,31 @@ struct tdb_context *tdb_open(const char *name, int hash_size, int tdb_flags,
 }
 
 /* a default logging function */
-static void null_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...) PRINTF_ATTRIBUTE(3, 4);
+static void null_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...) PRINTF_FMT(3, 4);
 static void null_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...)
 {
 }
 
+static bool check_header_hash(struct tdb_context *tdb,
+			      bool default_hash, uint32_t *m1, uint32_t *m2)
+{
+	tdb_header_hash(tdb, m1, m2);
+	if (tdb->header.magic1_hash == *m1 &&
+	    tdb->header.magic2_hash == *m2) {
+		return true;
+	}
+
+	/* If they explicitly set a hash, always respect it. */
+	if (!default_hash)
+		return false;
+
+	/* Otherwise, try the other inbuilt hash. */
+	if (tdb->hash_fn == tdb_old_hash)
+		tdb->hash_fn = tdb_jenkins_hash;
+	else
+		tdb->hash_fn = tdb_old_hash;
+	return check_header_hash(tdb, false, m1, m2);
+}
 
 struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
 				int open_flags, mode_t mode,
@@ -155,13 +188,14 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
 	unsigned char *vp;
 	uint32_t vertest;
 	unsigned v;
+	const char *hash_alg;
+	uint32_t magic1, magic2;
 
 	if (!(tdb = (struct tdb_context *)calloc(1, sizeof *tdb))) {
 		/* Can't log this */
 		errno = ENOMEM;
 		goto fail;
 	}
-
 	tdb_io_init(tdb);
 	tdb->fd = -1;
 #ifdef TDB_TRACE
@@ -177,7 +211,19 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
 		tdb->log.log_fn = null_log_fn;
 		tdb->log.log_private = NULL;
 	}
-	tdb->hash_fn = hash_fn ? hash_fn : default_tdb_hash;
+
+	if (hash_fn) {
+		tdb->hash_fn = hash_fn;
+		hash_alg = "the user defined";
+	} else {
+		/* This controls what we use when creating a tdb. */
+		if (tdb->flags & TDB_INCOMPATIBLE_HASH) {
+			tdb->hash_fn = tdb_jenkins_hash;
+		} else {
+			tdb->hash_fn = tdb_old_hash;
+		}
+		hash_alg = "either default";
+	}
 
 	/* cache the page size */
 	tdb->page_size = getpagesize();
@@ -213,11 +259,10 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
 	}
 
 	/*
-	 * TDB_ALLOW_NESTING is the default behavior.
-	 * Note: this may change in future versions!
+	 * TDB_DISALLOW_NESTING is the default behavior.
 	 */
-	if (!(tdb->flags & TDB_DISALLOW_NESTING)) {
-		tdb->flags |= TDB_ALLOW_NESTING;
+	if (!(tdb->flags & TDB_ALLOW_NESTING)) {
+		tdb->flags |= TDB_DISALLOW_NESTING;
 	}
 
 	/* internal databases don't mmap or lock, and start off cleared */
@@ -242,8 +287,8 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
         fcntl(tdb->fd, F_SETFD, v | FD_CLOEXEC);
 
 	/* ensure there is only one process initialising at once */
-	if (tdb->methods->brlock(tdb, F_WRLCK, GLOBAL_LOCK, 1, TDB_LOCK_WAIT) == -1) {
-		TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to get global lock on %s: %s\n",
+	if (tdb_nest_lock(tdb, OPEN_LOCK, F_WRLCK, TDB_LOCK_WAIT) == -1) {
+		TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to get open lock on %s: %s\n",
 			 name, strerror(errno)));
 		goto fail;	/* errno set by tdb_brlock */
 	}
@@ -251,7 +296,7 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
 	/* we need to zero database if we are the only one with it open */
 	if ((tdb_flags & TDB_CLEAR_IF_FIRST) &&
 	    (!tdb->read_only) &&
-	    (locked = (tdb->methods->brlock(tdb, F_WRLCK, ACTIVE_LOCK, 1, TDB_LOCK_NOWAIT|TDB_LOCK_PROBE) == 0))) {
+	    (locked = (tdb_nest_lock(tdb, ACTIVE_LOCK, F_WRLCK, TDB_LOCK_NOWAIT|TDB_LOCK_PROBE) == 0))) {
 		open_flags |= O_CREAT;
 		if (ftruncate(tdb->fd, 0) == -1) {
 			TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "
@@ -290,11 +335,31 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
 	if (fstat(tdb->fd, &st) == -1)
 		goto fail;
 
-	if (tdb->header.rwlocks != 0) {
+	if (tdb->header.rwlocks != 0 &&
+	    tdb->header.rwlocks != TDB_HASH_RWLOCK_MAGIC) {
 		TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: spinlocks no longer supported\n"));
 		goto fail;
 	}
 
+	if ((tdb->header.magic1_hash == 0) && (tdb->header.magic2_hash == 0)) {
+		/* older TDB without magic hash references */
+		tdb->hash_fn = tdb_old_hash;
+	} else if (!check_header_hash(tdb, !hash_fn, &magic1, &magic2)) {
+		TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "
+			 "%s was not created with %s hash function we are using\n"
+			 "magic1_hash[0x%08X %s 0x%08X] "
+			 "magic2_hash[0x%08X %s 0x%08X]\n",
+			 name, hash_alg,
+			 tdb->header.magic1_hash,
+			 (tdb->header.magic1_hash == magic1) ? "==" : "!=",
+			 magic1,
+			 tdb->header.magic2_hash,
+			 (tdb->header.magic2_hash == magic2) ? "==" : "!=",
+			 magic2));
+		errno = EINVAL;
+		goto fail;
+	}
+
 	/* Is it already in the open list?  If so, fail. */
 	if (tdb_already_open(st.st_dev, st.st_ino)) {
 		TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
@@ -314,7 +379,7 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
 	tdb->inode = st.st_ino;
 	tdb_mmap(tdb);
 	if (locked) {
-		if (tdb->methods->brunlock(tdb, F_WRLCK, ACTIVE_LOCK, 1) == -1) {
+		if (tdb_nest_unlock(tdb, ACTIVE_LOCK, F_WRLCK, false) == -1) {
 			TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
 				 "failed to take ACTIVE_LOCK on %s: %s\n",
 				 name, strerror(errno)));
@@ -329,8 +394,9 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
 
 	if (tdb_flags & TDB_CLEAR_IF_FIRST) {
 		/* leave this lock in place to indicate it's in use */
-		if (tdb->methods->brlock(tdb, F_RDLCK, ACTIVE_LOCK, 1, TDB_LOCK_WAIT) == -1)
+		if (tdb_nest_lock(tdb, ACTIVE_LOCK, F_RDLCK, TDB_LOCK_WAIT) == -1) {
 			goto fail;
+		}
 	}
 
 	/* if needed, run recovery */
@@ -342,7 +408,8 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
 	{
 		char tracefile[strlen(name) + 32];
 
-		sprintf(tracefile, "%s.trace.%u", name, getpid());
+		snprintf(tracefile, sizeof(tracefile),
+			 "%s.trace.%li", name, (long)getpid());
 		tdb->tracefd = open(tracefile, O_WRONLY|O_CREAT|O_EXCL, 0600);
 		if (tdb->tracefd >= 0) {
 			tdb_enable_seqnum(tdb);
@@ -356,9 +423,10 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
  internal:
 	/* Internal (memory-only) databases skip all the code above to
 	 * do with disk files, and resume here by releasing their
-	 * global lock and hooking into the active list. */
-	if (tdb->methods->brunlock(tdb, F_WRLCK, GLOBAL_LOCK, 1) == -1)
+	 * open lock and hooking into the active list. */
+	if (tdb_nest_unlock(tdb, OPEN_LOCK, F_WRLCK, false) == -1) {
 		goto fail;
+	}
 	tdb->next = tdbs;
 	tdbs = tdb;
 	return tdb;
@@ -382,6 +450,7 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
 	if (tdb->fd != -1)
 		if (close(tdb->fd) != 0)
 			TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to close tdb->fd on error!\n"));
+	SAFE_FREE(tdb->lockrecs);
 	SAFE_FREE(tdb);
 	errno = save_errno;
 	return NULL;
@@ -454,9 +523,7 @@ void *tdb_get_logging_private(struct tdb_context *tdb)
 	return tdb->log.log_private;
 }
 
-/* reopen a tdb - this can be used after a fork to ensure that we have an independent
-   seek pointer from our parent and to re-establish locks */
-int tdb_reopen(struct tdb_context *tdb)
+static int tdb_reopen_internal(struct tdb_context *tdb, bool active_lock)
 {
 	struct stat st;
 
@@ -464,7 +531,7 @@ int tdb_reopen(struct tdb_context *tdb)
 		return 0; /* Nothing to do. */
 	}
 
-	if (tdb->num_locks != 0 || tdb->global_lock.count) {
+	if (tdb_have_extra_locks(tdb)) {
 		TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_reopen: reopen not allowed with locks held\n"));
 		goto fail;
 	}
@@ -485,11 +552,6 @@ int tdb_reopen(struct tdb_context *tdb)
 		TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: open failed (%s)\n", strerror(errno)));
 		goto fail;
 	}
-	if ((tdb->flags & TDB_CLEAR_IF_FIRST) && 
-	    (tdb->methods->brlock(tdb, F_RDLCK, ACTIVE_LOCK, 1, TDB_LOCK_WAIT) == -1)) {
-		TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: failed to obtain active lock\n"));
-		goto fail;
-	}
 	if (fstat(tdb->fd, &st) != 0) {
 		TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: fstat failed (%s)\n", strerror(errno)));
 		goto fail;
@@ -500,6 +562,15 @@ int tdb_reopen(struct tdb_context *tdb)
 	}
 	tdb_mmap(tdb);
 
+	/* We may still think we hold the active lock. */
+	tdb->num_lockrecs = 0;
+	SAFE_FREE(tdb->lockrecs);
+
+	if (active_lock && tdb_nest_lock(tdb, ACTIVE_LOCK, F_RDLCK, TDB_LOCK_WAIT) == -1) {
+		TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: failed to obtain active lock\n"));
+		goto fail;
+	}
+
 	return 0;
 
 fail:
@@ -507,12 +578,21 @@ fail:
 	return -1;
 }
 
+/* reopen a tdb - this can be used after a fork to ensure that we have an independent
+   seek pointer from our parent and to re-establish locks */
+int tdb_reopen(struct tdb_context *tdb)
+{
+	return tdb_reopen_internal(tdb, tdb->flags & TDB_CLEAR_IF_FIRST);
+}
+
 /* reopen all tdb's */
 int tdb_reopen_all(int parent_longlived)
 {
 	struct tdb_context *tdb;
 
 	for (tdb=tdbs; tdb; tdb = tdb->next) {
+		bool active_lock = (tdb->flags & TDB_CLEAR_IF_FIRST);
+
 		/*
 		 * If the parent is longlived (ie. a
 		 * parent daemon architecture), we know
@@ -526,10 +606,10 @@ int tdb_reopen_all(int parent_longlived)
 		 */
 		if (parent_longlived) {
 			/* Ensure no clear-if-first. */
-			tdb->flags &= ~TDB_CLEAR_IF_FIRST;
+			active_lock = false;
 		}
 
-		if (tdb_reopen(tdb) != 0)
+		if (tdb_reopen_internal(tdb, active_lock) != 0)
 			return -1;
 	}