X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Ftdb%2Fopen.c;h=aa974431db3fae958d074469c8d6e948e1d097a9;hp=95f8f4c940116fa8f64eec4a7cd57ba9c72644b0;hb=d9cbd7d4454ae35e4e2f6d18a9469bf26948e4b9;hpb=d117f992bde6b7157a8eecbce8a026f2aa7ab4ae

diff --git a/ccan/tdb/open.c b/ccan/tdb/open.c
index 95f8f4c9..aa974431 100644
--- a/ccan/tdb/open.c
+++ b/ccan/tdb/open.c
@@ -71,6 +71,11 @@ static int tdb_new_database(struct tdb_context *tdb, int 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;
@@ -146,11 +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,
@@ -163,9 +188,8 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
 	unsigned char *vp;
 	uint32_t vertest;
 	unsigned v;
-	uint32_t magic1_hash;
-	uint32_t magic2_hash;
 	const char *hash_alg;
+	uint32_t magic1, magic2;
 
 	if (!(tdb = (struct tdb_context *)calloc(1, sizeof *tdb))) {
 		/* Can't log this */
@@ -190,10 +214,15 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
 
 	if (hash_fn) {
 		tdb->hash_fn = hash_fn;
-		hash_alg = "user defined";
+		hash_alg = "the user defined";
 	} else {
-		tdb->hash_fn = tdb_old_hash;
-		hash_alg = "default";
+		/* 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 */
@@ -306,28 +335,27 @@ 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;
 	}
 
-	tdb_header_hash(tdb, &magic1_hash, &magic2_hash);
-
 	if ((tdb->header.magic1_hash == 0) && (tdb->header.magic2_hash == 0)) {
 		/* older TDB without magic hash references */
-	} else if ((tdb->header.magic1_hash != magic1_hash) ||
-		   (tdb->header.magic2_hash != magic2_hash)) {
+		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 the %s hash function we are using\n"
+			 "%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_hash) ? "==" : "!=",
-			 magic1_hash,
+			 (tdb->header.magic1_hash == magic1) ? "==" : "!=",
+			 magic1,
 			 tdb->header.magic2_hash,
-			 (tdb->header.magic2_hash == magic2_hash) ? "==" : "!=",
-			 magic2_hash));
+			 (tdb->header.magic2_hash == magic2) ? "==" : "!=",
+			 magic2));
 		errno = EINVAL;
 		goto fail;
 	}