tdb: put example hashes into header, so we notice incorrect hash_fn.

[ccan] / ccan / tdb / open.c

diff --git a/ccan/tdb/open.c b/ccan/tdb/open.c
index 437a5fc38d1706e9b5f3e846876f8aa4e8d9da75..aa32a45eda3957aa04e8c9444a9ba2bd749b1207 100644 (file)
--- a/ccan/tdb/open.c
+++ b/ccan/tdb/open.c
@@ -44,6 +44,25 @@ static unsigned int default_tdb_hash(TDB_DATA *key)
        return (1103515243 * value + 12345);  
 }
 
        return (1103515243 * value + 12345);  
 }
 

+/* 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)
+{
+       TDB_DATA hash_key;
+       uint32_t tdb_magic = TDB_MAGIC;
+
+       hash_key.dptr = (unsigned char *)TDB_MAGIC_FOOD;
+       hash_key.dsize = sizeof(TDB_MAGIC_FOOD);
+       *magic1_hash = tdb->hash_fn(&hash_key);
+
+       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)
 
 /* initialise a new database with a specified hash size */
 static int tdb_new_database(struct tdb_context *tdb, int hash_size)


@@ -63,7 +82,9 @@ 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;
        /* Fill in the header */
        newdb->version = TDB_VERSION;
        newdb->hash_size = hash_size;

-       newdb->hashcheck = hashcheck(tdb);
+
+       tdb_header_hash(tdb, &newdb->magic1_hash, &newdb->magic2_hash);
+

        if (tdb->flags & TDB_INTERNAL) {
                tdb->map_size = size;
                tdb->map_ptr = (char *)newdb;
        if (tdb->flags & TDB_INTERNAL) {
                tdb->map_size = size;
                tdb->map_ptr = (char *)newdb;


@@ -144,18 +165,6 @@ static void null_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, con
 {
 }
 
 {
 }
 

-uint32_t hashcheck(struct tdb_context *tdb)
-{
-       uint32_t vals[] = { TDB_VERSION, TDB_MAGIC };
-       TDB_DATA hashkey = { (unsigned char *)vals, sizeof(vals) };
-
-       /* If we're using the default hash, let old code still open the db. */
-       if (tdb->hash_fn == default_tdb_hash)
-               return 0;
-
-       /* Only let new hash-aware TDB code open it (must not be zero!) */
-       return (tdb->hash_fn(&hashkey) | 1);
-}

 
 struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
                                int open_flags, mode_t mode,
 
 struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
                                int open_flags, mode_t mode,


@@ -168,6 +177,9 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
        unsigned char *vp;
        uint32_t vertest;
        unsigned v;
        unsigned char *vp;
        uint32_t vertest;
        unsigned v;

+       uint32_t magic1_hash;
+       uint32_t magic2_hash;
+       const char *hash_alg;

 
        if (!(tdb = (struct tdb_context *)calloc(1, sizeof *tdb))) {
                /* Can't log this */
 
        if (!(tdb = (struct tdb_context *)calloc(1, sizeof *tdb))) {
                /* Can't log this */


@@ -189,7 +201,14 @@ 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->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 = "user defined";
+       } else {
+               tdb->hash_fn = default_tdb_hash;
+               hash_alg = "default";
+       }

 
        /* cache the page size */
        tdb->page_size = getpagesize();
 
        /* cache the page size */
        tdb->page_size = getpagesize();


@@ -301,8 +320,29 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
        if (fstat(tdb->fd, &st) == -1)
                goto fail;
 
        if (fstat(tdb->fd, &st) == -1)
                goto fail;
 

-       if (tdb->header.hashcheck != hashcheck(tdb)) {
-               TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: wrong hash?\n"));
+       if (tdb->header.rwlocks != 0) {
+               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_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "
+                        "%s was not created with the %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.magic2_hash,
+                        (tdb->header.magic2_hash == magic2_hash) ? "==" : "!=",
+                        magic2_hash));
+               errno = EINVAL;

                goto fail;
        }
 
                goto fail;
        }