diff options
| -rw-r--r-- | lib/tdb/common/tdb.c | 29 | ||||
| -rw-r--r-- | lib/tdb/common/tdb_private.h | 10 |
2 files changed, 39 insertions, 0 deletions
diff --git a/lib/tdb/common/tdb.c b/lib/tdb/common/tdb.c index 04f7f97eade..62df8eb1d32 100644 --- a/lib/tdb/common/tdb.c +++ b/lib/tdb/common/tdb.c @@ -79,6 +79,35 @@ static int tdb_key_compare(TDB_DATA key, TDB_DATA data, void *private_data) return memcmp(data.dptr, key.dptr, data.dsize); } +void tdb_chainwalk_init(struct tdb_chainwalk_ctx *ctx, tdb_off_t ptr) +{ + *ctx = (struct tdb_chainwalk_ctx) { .slow_ptr = ptr }; +} + +bool tdb_chainwalk_check(struct tdb_context *tdb, + struct tdb_chainwalk_ctx *ctx, + tdb_off_t next_ptr) +{ + int ret; + + if (ctx->slow_chase) { + ret = tdb_ofs_read(tdb, ctx->slow_ptr, &ctx->slow_ptr); + if (ret == -1) { + return false; + } + } + ctx->slow_chase = !ctx->slow_chase; + + if (next_ptr == ctx->slow_ptr) { + tdb->ecode = TDB_ERR_CORRUPT; + TDB_LOG((tdb, TDB_DEBUG_ERROR, + "tdb_chainwalk_check: circular chain\n")); + return false; + } + + return true; +} + /* Returns 0 on fail. On success, return offset of record, and fills in rec */ static tdb_off_t tdb_find(struct tdb_context *tdb, TDB_DATA key, uint32_t hash, diff --git a/lib/tdb/common/tdb_private.h b/lib/tdb/common/tdb_private.h index eeac10a49ad..307cad92c2a 100644 --- a/lib/tdb/common/tdb_private.h +++ b/lib/tdb/common/tdb_private.h @@ -191,6 +191,11 @@ struct tdb_lock_type { uint32_t ltype; }; +struct tdb_chainwalk_ctx { + tdb_off_t slow_ptr; + bool slow_chase; +}; + struct tdb_traverse_lock { struct tdb_traverse_lock *next; uint32_t off; @@ -198,6 +203,11 @@ struct tdb_traverse_lock { int lock_rw; }; +void tdb_chainwalk_init(struct tdb_chainwalk_ctx *ctx, tdb_off_t ptr); +bool tdb_chainwalk_check(struct tdb_context *tdb, + struct tdb_chainwalk_ctx *ctx, + tdb_off_t next_ptr); + enum tdb_lock_flags { /* WAIT == F_SETLKW, NOWAIT == F_SETLK */ TDB_LOCK_NOWAIT = 0, |