tdb: automatically identify Jenkins hash tdbs

If the caller to tdb_open_ex() doesn't specify a hash, and tdb_old_hash
doesn't match, try tdb_jenkins_hash.

This makes life simpler, especially with the upcoming TDB_INCOMPATIBLE_HASH
flag.

diff --git a/ccan/tdb/open.c b/ccan/tdb/open.c
index 95f8f4c940116fa8f64eec4a7cd57ba9c72644b0..b92567b37819855a754dd4b03b94cf14fc21f800 100644 (file)
--- a/ccan/tdb/open.c
+++ b/ccan/tdb/open.c
@@ -151,6 +151,23 @@ static void null_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, con
 {
 }
 
+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. */
+       tdb->hash_fn = tdb_jenkins_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 +180,8 @@ 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 +206,10 @@ 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";
+               hash_alg = "either default";
        }
 
        /* cache the page size */
@@ -311,23 +327,20 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
                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)) {
+       } 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;
        }

diff --git a/ccan/tdb/test/run-wronghash-fail.c b/ccan/tdb/test/run-wronghash-fail.c
index 2f7422aaa61af0e522fc2ec9d08ebff5d7e4a40c..17fd867e980db322a918a33aca640c2212912159 100644 (file)
--- a/ccan/tdb/test/run-wronghash-fail.c
+++ b/ccan/tdb/test/run-wronghash-fail.c
@@ -25,9 +25,10 @@ int main(int argc, char *argv[])
 {
        struct tdb_context *tdb;
        unsigned int log_count;
+       TDB_DATA d;
        struct tdb_logging_context log_ctx = { log_fn, &log_count };
 
-       plan_tests(18);
+       plan_tests(28);
 
        /* Create with default hash. */
        log_count = 0;
@@ -35,6 +36,9 @@ int main(int argc, char *argv[])
                          O_CREAT|O_RDWR|O_TRUNC, 0600, &log_ctx, NULL);
        ok1(tdb);
        ok1(log_count == 0);
+       d.dptr = (void *)"Hello";
+       d.dsize = 5;
+       ok1(tdb_store(tdb, d, d, TDB_INSERT) == 0);
        tdb_close(tdb);
 
        /* Fail to open with different hash. */
@@ -55,20 +59,20 @@ int main(int argc, char *argv[])
        /* Endian should be no problem. */
        log_count = 0;
        tdb = tdb_open_ex("test/jenkins-le-hash.tdb", 0, 0, O_RDWR, 0,
-                         &log_ctx, NULL);
+                         &log_ctx, tdb_old_hash);
        ok1(!tdb);
        ok1(log_count == 1);
 
        log_count = 0;
        tdb = tdb_open_ex("test/jenkins-be-hash.tdb", 0, 0, O_RDWR, 0,
-                         &log_ctx, NULL);
+                         &log_ctx, tdb_old_hash);
        ok1(!tdb);
        ok1(log_count == 1);
 
        log_count = 0;
-       /* Fail to open with default hash. */
+       /* Fail to open with old default hash. */
        tdb = tdb_open_ex("run-wronghash-fail.tdb", 0, 0, O_RDWR, 0,
-                         &log_ctx, NULL);
+                         &log_ctx, tdb_old_hash);
        ok1(!tdb);
        ok1(log_count == 1);
 
@@ -88,5 +92,31 @@ int main(int argc, char *argv[])
        ok1(tdb_check(tdb, NULL, NULL) == 0);
        tdb_close(tdb);
 
+       /* It should open with jenkins hash if we don't specify. */
+       log_count = 0;
+       tdb = tdb_open_ex("test/jenkins-le-hash.tdb", 0, 0, O_RDWR, 0,
+                         &log_ctx, NULL);
+       ok1(tdb);
+       ok1(log_count == 0);
+       ok1(tdb_check(tdb, NULL, NULL) == 0);
+       tdb_close(tdb);
+
+       log_count = 0;
+       tdb = tdb_open_ex("test/jenkins-be-hash.tdb", 0, 0, O_RDWR, 0,
+                         &log_ctx, NULL);
+       ok1(tdb);
+       ok1(log_count == 0);
+       ok1(tdb_check(tdb, NULL, NULL) == 0);
+       tdb_close(tdb);
+
+       log_count = 0;
+       tdb = tdb_open_ex("run-wronghash-fail.tdb", 0, 0, O_RDONLY,
+                         0, &log_ctx, NULL);
+       ok1(tdb);
+       ok1(log_count == 0);
+       ok1(tdb_check(tdb, NULL, NULL) == 0);
+       tdb_close(tdb);
+
+
        return exit_status();
 }