For ITS#7789: Ensure mapsize >= pages in use.

Check new mapsizes against mm_last_pg.  Move
mdb_env_init_meta0() so it can set mm_last_pg earlier.

diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index d35d275576a5d555f80be4728cb1689b49a4d770..7a71e18a0ddf99e05e9b8007a87eb7d18ee5e2d0 100644 (file)
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -3507,6 +3507,7 @@ mdb_env_read_header(MDB_env *env, MDB_meta *meta)
        return 0;
 }
 
+/** Fill in most of the zeroed #MDB_meta for an empty database environment */
 static void ESECT
 mdb_env_init_meta0(MDB_env *env, MDB_meta *meta)
 {
@@ -3523,7 +3524,7 @@ mdb_env_init_meta0(MDB_env *env, MDB_meta *meta)
 
 /** Write the environment parameters of a freshly created DB environment.
  * @param[in] env the environment handle
- * @param[out] meta address of where to store the meta information
+ * @param[in] meta the #MDB_meta to write
  * @return 0 on success, non-zero on failure.
  */
 static int ESECT
@@ -3550,8 +3551,6 @@ mdb_env_init_meta(MDB_env *env, MDB_meta *meta)
 
        psize = env->me_psize;
 
-       mdb_env_init_meta0(env, meta);
-
        p = calloc(2, psize);
        p->mp_pgno = 0;
        p->mp_flags = P_META;
@@ -3825,16 +3824,16 @@ mdb_env_set_mapsize(MDB_env *env, size_t size)
         */
        if (env->me_map) {
                int rc;
+               MDB_meta *meta;
                void *old;
                if (env->me_txn)
                        return EINVAL;
+               meta = env->me_metas[mdb_env_pick_meta(env)];
                if (!size)
-                       size = env->me_metas[mdb_env_pick_meta(env)]->mm_mapsize;
-               else if (size < env->me_mapsize) {
-                       /* If the configured size is smaller, make sure it's
-                        * still big enough. Silently round up to minimum if not.
-                        */
-                       size_t minsize = (env->me_metas[mdb_env_pick_meta(env)]->mm_last_pg + 1) * env->me_psize;
+                       size = meta->mm_mapsize;
+               {
+                       /* Silently round up to minimum if the size is too small */
+                       size_t minsize = (meta->mm_last_pg + 1) * env->me_psize;
                        if (size < minsize)
                                size = minsize;
                }
@@ -3917,8 +3916,6 @@ mdb_env_open2(MDB_env *env)
                env->me_pidquery = PROCESS_QUERY_INFORMATION;
 #endif /* _WIN32 */
 
-       memset(&meta, 0, sizeof(meta));
-
        if ((i = mdb_env_read_header(env, &meta)) != 0) {
                if (i != ENOENT)
                        return i;
@@ -3927,24 +3924,26 @@ mdb_env_open2(MDB_env *env)
                env->me_psize = env->me_os_psize;
                if (env->me_psize > MAX_PAGESIZE)
                        env->me_psize = MAX_PAGESIZE;
+               memset(&meta, 0, sizeof(meta));
+               mdb_env_init_meta0(env, &meta);
+               meta.mm_mapsize = DEFAULT_MAPSIZE;
        } else {
                env->me_psize = meta.mm_psize;
        }
 
        /* Was a mapsize configured? */
        if (!env->me_mapsize) {
-               /* If this is a new environment, take the default,
-                * else use the size recorded in the existing env.
-                */
-               env->me_mapsize = newenv ? DEFAULT_MAPSIZE : meta.mm_mapsize;
-       } else if (env->me_mapsize < meta.mm_mapsize) {
-               /* If the configured size is smaller, make sure it's
-                * still big enough. Silently round up to minimum if not.
+               env->me_mapsize = meta.mm_mapsize;
+       }
+       {
+               /* Make sure mapsize >= committed data size.  Even when using
+                * mm_mapsize, which could be broken in old files (ITS#7789).
                 */
                size_t minsize = (meta.mm_last_pg + 1) * meta.mm_psize;
                if (env->me_mapsize < minsize)
                        env->me_mapsize = minsize;
        }
+       meta.mm_mapsize = env->me_mapsize;
 
        rc = mdb_env_map(env, (flags & MDB_FIXEDMAP) ? meta.mm_address : NULL);
        if (rc)