tdb2: approximate INCOMPATIBLE_HASH flag with tdb1_incompatible_hash()
authorRusty Russell <rusty@rustcorp.com.au>
Wed, 31 Aug 2011 05:50:16 +0000 (15:20 +0930)
committerRusty Russell <rusty@rustcorp.com.au>
Wed, 31 Aug 2011 05:50:16 +0000 (15:20 +0930)
Rather than leak TDB_INCOMPATIBLE_HASH through to the TDB2 API, we make
it that if they use the tdb1_incompatible_hash function as their hash,
then we treat it as if they had specified the TDB_INCOMPATIBLE_HASH
flag (ie. we mark the header so it's unusable by tdb < 1.2.6).

This precludes the possibility of using TDB_INCOMPATIBLE_HASH with a
custom hash function: that used to allow the user to ensure that old TDB
versions couldn't open the TDB file (and recent ones check the header to
ensure they're using the right hash).  But that's a small loss.

ccan/tdb2/tdb1.h
ccan/tdb2/tdb1_hash.c
ccan/tdb2/tdb1_open.c
ccan/tdb2/test/run-tdb1-incompatible.c
ccan/tdb2/test/run-tdb1-oldhash.c
ccan/tdb2/test/run-tdb1-wronghash-fail.c

index b2435ba53e3eff8a1f04a2c35220aaf4c54c9fa5..3869373fbe8b47cdbae4c0d2f4c03fc47f0173c2 100644 (file)
@@ -49,7 +49,6 @@
 #define TDB1_VOLATILE   256 /** Activate the per-hashchain freelist, default 5 */
 #define TDB1_ALLOW_NESTING 512 /** Allow transactions to nest */
 #define TDB1_DISALLOW_NESTING 1024 /** Disallow transactions to nest */
-#define TDB1_INCOMPATIBLE_HASH 2048 /** Better hashing: can't be opened by tdb < 1.2.6. */
 
 /** This is the context structure that is returned from a db open. */
 typedef struct tdb1_context TDB1_CONTEXT;
@@ -121,7 +120,7 @@ int tdb1_hash_size(struct tdb1_context *tdb);
 
 void tdb1_increment_seqnum_nonblock(struct tdb1_context *tdb);
 
-unsigned int tdb1_jenkins_hash(TDB_DATA *key);
+unsigned int tdb1_incompatible_hash(TDB_DATA *key);
 
 int tdb1_check(struct tdb1_context *tdb,
              int (*check) (TDB_DATA key, TDB_DATA data, void *private_data),
index 50e49505ca936da61f4bcec9d7b0cf910fe91369..886577da7020eefc355c87278c72845892523e9c 100644 (file)
@@ -339,7 +339,7 @@ static uint32_t hashlittle( const void *key, size_t length )
   return c;
 }
 
-unsigned int tdb1_jenkins_hash(TDB_DATA *key)
+unsigned int tdb1_incompatible_hash(TDB_DATA *key)
 {
        return hashlittle(key->dptr, key->dsize);
 }
index 30c11956ac185b7daeb53de5b92e960a0cc18b6e..f53a32b5befa977bc2a927dee37ec6da26f9bb81 100644 (file)
@@ -72,7 +72,7 @@ static int tdb1_new_database(struct tdb1_context *tdb, int hash_size)
 
        /* Make sure older tdbs (which don't check the magic hash fields)
         * will refuse to open this TDB. */
-       if (tdb->flags & TDB1_INCOMPATIBLE_HASH)
+       if (tdb->hash_fn == tdb1_incompatible_hash)
                newdb->rwlocks = TDB1_HASH_RWLOCK_MAGIC;
 
        if (tdb->flags & TDB1_INTERNAL) {
@@ -135,25 +135,28 @@ struct tdb1_context *tdb1_open(const char *name, int hash_size, int tdb1_flags,
        return tdb1_open_ex(name, hash_size, tdb1_flags, open_flags, mode, NULL, NULL);
 }
 
-static bool check_header_hash(struct tdb1_context *tdb,
-                             bool default_hash, uint32_t *m1, uint32_t *m2)
+static bool hash_correct(struct tdb1_context *tdb,
+                        uint32_t *m1, uint32_t *m2)
 {
        tdb1_header_hash(tdb, m1, m2);
-       if (tdb->header.magic1_hash == *m1 &&
-           tdb->header.magic2_hash == *m2) {
-               return true;
-       }
+       return (tdb->header.magic1_hash == *m1 &&
+               tdb->header.magic2_hash == *m2);
+}
 
-       /* If they explicitly set a hash, always respect it. */
-       if (!default_hash)
-               return false;
+static bool check_header_hash(struct tdb1_context *tdb,
+                             uint32_t *m1, uint32_t *m2)
+{
+       if (hash_correct(tdb, m1, m2))
+               return true;
 
-       /* Otherwise, try the other inbuilt hash. */
+       /* If they use one inbuilt, try the other inbuilt hash. */
        if (tdb->hash_fn == tdb1_old_hash)
-               tdb->hash_fn = tdb1_jenkins_hash;
-       else
+               tdb->hash_fn = tdb1_incompatible_hash;
+       else if (tdb->hash_fn == tdb1_incompatible_hash)
                tdb->hash_fn = tdb1_old_hash;
-       return check_header_hash(tdb, false, m1, m2);
+       else
+               return false;
+       return hash_correct(tdb, m1, m2);
 }
 
 struct tdb1_context *tdb1_open_ex(const char *name, int hash_size, int tdb1_flags,
@@ -216,15 +219,13 @@ struct tdb1_context *tdb1_open_ex(const char *name, int hash_size, int tdb1_flag
 
        if (hash_fn) {
                tdb->hash_fn = hash_fn;
-               hash_alg = "the user defined";
+               if (hash_fn == tdb1_incompatible_hash)
+                       hash_alg = "tdb1_incompatible_hash";
+               else
+                       hash_alg = "the user defined";
        } else {
-               /* This controls what we use when creating a tdb. */
-               if (tdb->flags & TDB1_INCOMPATIBLE_HASH) {
-                       tdb->hash_fn = tdb1_jenkins_hash;
-               } else {
-                       tdb->hash_fn = tdb1_old_hash;
-               }
-               hash_alg = "either default";
+               tdb->hash_fn = tdb1_old_hash;
+               hash_alg = "default";
        }
 
        /* cache the page size */
@@ -353,7 +354,7 @@ struct tdb1_context *tdb1_open_ex(const char *name, int hash_size, int tdb1_flag
        if ((tdb->header.magic1_hash == 0) && (tdb->header.magic2_hash == 0)) {
                /* older TDB without magic hash references */
                tdb->hash_fn = tdb1_old_hash;
-       } else if (!check_header_hash(tdb, !hash_fn, &magic1, &magic2)) {
+       } else if (!check_header_hash(tdb, &magic1, &magic2)) {
                tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_USE_ERROR,
                           "tdb1_open_ex: "
                           "%s was not created with %s hash function we are using\n"
index 51aa52d4b7e58744defbe0e86359f66051cb13c4..6f3aee0336ebeac25f5f0026df462d60d55aff0a 100644 (file)
@@ -31,6 +31,16 @@ static unsigned int hdr_rwlocks(const char *fname)
        return hdr.rwlocks;
 }
 
+static unsigned int jenkins_hashfn(TDB_DATA *key)
+{
+       return hashlittle(key->dptr, key->dsize);
+}
+
+static unsigned int old_hash(TDB_DATA *key)
+{
+       return tdb1_old_hash(key);
+}
+
 int main(int argc, char *argv[])
 {
        struct tdb1_context *tdb;
@@ -61,11 +71,12 @@ int main(int argc, char *argv[])
                /* Should not have marked rwlocks field. */
                ok1(hdr_rwlocks("run-incompatible.tdb") == 0);
 
-               /* We can still open any old-style with incompat flag. */
+               /* We can still open any old-style with incompat hash. */
                log_count = 0;
                tdb = tdb1_open_ex("run-incompatible.tdb", 0,
-                                 TDB1_INCOMPATIBLE_HASH,
-                                 O_RDWR, 0600, &log_ctx, NULL);
+                                 TDB_DEFAULT,
+                                 O_RDWR, 0600, &log_ctx,
+                                  tdb1_incompatible_hash);
                ok1(tdb);
                ok1(log_count == 0);
                d = tdb1_fetch(tdb, d);
@@ -76,7 +87,7 @@ int main(int argc, char *argv[])
 
                log_count = 0;
                tdb = tdb1_open_ex("test/jenkins-le-hash.tdb1", 0, 0, O_RDONLY,
-                                 0, &log_ctx, tdb1_jenkins_hash);
+                                 0, &log_ctx, jenkins_hashfn);
                ok1(tdb);
                ok1(log_count == 0);
                ok1(tdb1_check(tdb, NULL, NULL) == 0);
@@ -84,18 +95,18 @@ int main(int argc, char *argv[])
 
                log_count = 0;
                tdb = tdb1_open_ex("test/jenkins-be-hash.tdb1", 0, 0, O_RDONLY,
-                                 0, &log_ctx, tdb1_jenkins_hash);
+                                 0, &log_ctx, jenkins_hashfn);
                ok1(tdb);
                ok1(log_count == 0);
                ok1(tdb1_check(tdb, NULL, NULL) == 0);
                tdb1_close(tdb);
 
-               /* OK, now create with incompatible flag, default hash. */
+               /* OK, now create with incompatible hash. */
                log_count = 0;
                tdb = tdb1_open_ex("run-incompatible.tdb", 0,
-                                 flags|TDB1_INCOMPATIBLE_HASH,
+                                 flags,
                                  O_CREAT|O_RDWR|O_TRUNC, 0600, &log_ctx,
-                                 NULL);
+                                 tdb1_incompatible_hash);
                ok1(tdb);
                ok1(log_count == 0);
                d.dptr = (void *)"Hello";
@@ -109,14 +120,14 @@ int main(int argc, char *argv[])
                /* Cannot open with old hash. */
                log_count = 0;
                tdb = tdb1_open_ex("run-incompatible.tdb", 0, 0,
-                                 O_RDWR, 0600, &log_ctx, tdb1_old_hash);
+                                 O_RDWR, 0600, &log_ctx, old_hash);
                ok1(!tdb);
                ok1(log_count == 1);
 
                /* Can open with jenkins hash. */
                log_count = 0;
                tdb = tdb1_open_ex("run-incompatible.tdb", 0, 0,
-                                 O_RDWR, 0600, &log_ctx, tdb1_jenkins_hash);
+                                 O_RDWR, 0600, &log_ctx, jenkins_hashfn);
                ok1(tdb);
                ok1(log_count == 0);
                d = tdb1_fetch(tdb, d);
@@ -139,10 +150,11 @@ int main(int argc, char *argv[])
                ok1(tdb1_check(tdb, NULL, NULL) == 0);
                tdb1_close(tdb);
 
+               /* FIXME: Not possible with TDB2 :( */
                /* We can also use incompatible hash with other hashes. */
                log_count = 0;
                tdb = tdb1_open_ex("run-incompatible.tdb", 0,
-                                 flags|TDB1_INCOMPATIBLE_HASH,
+                                 flags,
                                  O_CREAT|O_RDWR|O_TRUNC, 0600, &log_ctx,
                                  tdb1_dumb_hash);
                ok1(tdb);
@@ -152,8 +164,8 @@ int main(int argc, char *argv[])
                ok1(tdb1_store(tdb, d, d, TDB_INSERT) == 0);
                tdb1_close(tdb);
 
-               /* Should have marked rwlocks field. */
-               ok1(hdr_rwlocks("run-incompatible.tdb") == rwmagic);
+               /* FIXME: Should have marked rwlocks field. */
+               ok1(hdr_rwlocks("run-incompatible.tdb") != rwmagic);
 
                /* It should not open if we don't specify. */
                log_count = 0;
index 32b4200d5456b0436bec4255dd02cee2c56f6aee..4f74dbb95b41ac19bc46340b722b3e6c638a227d 100644 (file)
@@ -25,13 +25,13 @@ int main(int argc, char *argv[])
        tdb1_close(tdb);
 
        tdb = tdb1_open_ex("test/old-nohash-le.tdb1", 0, 0, O_RDWR, 0,
-                         &taplogctx, tdb1_jenkins_hash);
+                         &taplogctx, tdb1_incompatible_hash);
        ok1(tdb);
        ok1(tdb1_check(tdb, NULL, NULL) == 0);
        tdb1_close(tdb);
 
        tdb = tdb1_open_ex("test/old-nohash-be.tdb1", 0, 0, O_RDWR, 0,
-                         &taplogctx, tdb1_jenkins_hash);
+                         &taplogctx, tdb1_incompatible_hash);
        ok1(tdb);
        ok1(tdb1_check(tdb, NULL, NULL) == 0);
        tdb1_close(tdb);
index 368835ed7f263a73e0d34769da078b4965cc7c0c..97a8293e7d255e5ea1bd1877e6608769e714d07b 100644 (file)
@@ -11,6 +11,18 @@ static void log_fn(struct tdb1_context *tdb, enum tdb_log_level level,
                (*count)++;
 }
 
+static unsigned int jenkins_hashfn(TDB_DATA *key)
+{
+       return hashlittle(key->dptr, key->dsize);
+}
+
+/* the tdb1_old_hash function is "magic" as it automatically makes us test the
+ * tdb1_incompatible_hash as well, so use this wrapper. */
+static unsigned int old_hash(TDB_DATA *key)
+{
+       return tdb1_old_hash(key);
+}
+
 int main(int argc, char *argv[])
 {
        struct tdb1_context *tdb;
@@ -33,7 +45,7 @@ int main(int argc, char *argv[])
 
        /* Fail to open with different hash. */
        tdb = tdb1_open_ex("run-wronghash-fail.tdb", 0, 0, O_RDWR, 0,
-                         &log_ctx, tdb1_jenkins_hash);
+                         &log_ctx, jenkins_hashfn);
        ok1(!tdb);
        ok1(log_count == 1);
 
@@ -41,7 +53,7 @@ int main(int argc, char *argv[])
        log_count = 0;
        tdb = tdb1_open_ex("run-wronghash-fail.tdb", 0, 0,
                          O_CREAT|O_RDWR|O_TRUNC,
-                         0600, &log_ctx, tdb1_jenkins_hash);
+                         0600, &log_ctx, jenkins_hashfn);
        ok1(tdb);
        ok1(log_count == 0);
        tdb1_close(tdb);
@@ -49,26 +61,26 @@ int main(int argc, char *argv[])
        /* Endian should be no problem. */
        log_count = 0;
        tdb = tdb1_open_ex("test/jenkins-le-hash.tdb1", 0, 0, O_RDWR, 0,
-                         &log_ctx, tdb1_old_hash);
+                         &log_ctx, old_hash);
        ok1(!tdb);
        ok1(log_count == 1);
 
        log_count = 0;
        tdb = tdb1_open_ex("test/jenkins-be-hash.tdb1", 0, 0, O_RDWR, 0,
-                         &log_ctx, tdb1_old_hash);
+                         &log_ctx, old_hash);
        ok1(!tdb);
        ok1(log_count == 1);
 
        log_count = 0;
        /* Fail to open with old default hash. */
        tdb = tdb1_open_ex("run-wronghash-fail.tdb", 0, 0, O_RDWR, 0,
-                         &log_ctx, tdb1_old_hash);
+                         &log_ctx, old_hash);
        ok1(!tdb);
        ok1(log_count == 1);
 
        log_count = 0;
        tdb = tdb1_open_ex("test/jenkins-le-hash.tdb1", 0, 0, O_RDONLY,
-                         0, &log_ctx, tdb1_jenkins_hash);
+                         0, &log_ctx, tdb1_incompatible_hash);
        ok1(tdb);
        ok1(log_count == 0);
        ok1(tdb1_check(tdb, NULL, NULL) == 0);
@@ -76,7 +88,7 @@ int main(int argc, char *argv[])
 
        log_count = 0;
        tdb = tdb1_open_ex("test/jenkins-be-hash.tdb1", 0, 0, O_RDONLY,
-                         0, &log_ctx, tdb1_jenkins_hash);
+                         0, &log_ctx, tdb1_incompatible_hash);
        ok1(tdb);
        ok1(log_count == 0);
        ok1(tdb1_check(tdb, NULL, NULL) == 0);