From f6900d2358ca0ec2f2dc776b9e42e4fca7bffbdf Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Tue, 10 May 2011 11:07:21 +0930 Subject: [PATCH] tdb2: check pid before unlock. The original code assumed that unlocking would fail if we didn't have a lock; this isn't true (at least, on my machine). So we have to always check the pid before unlocking. --- ccan/tdb2/lock.c | 14 ++++++++------ ccan/tdb2/test/run-fork-test.c | 4 ++-- 2 files changed, 10 insertions(+), 8 deletions(-) diff --git a/ccan/tdb2/lock.c b/ccan/tdb2/lock.c index 4033d0af..49313a54 100644 --- a/ccan/tdb2/lock.c +++ b/ccan/tdb2/lock.c @@ -37,7 +37,7 @@ static enum TDB_ERROR owner_conflict(struct tdb_context *tdb, const char *call) call); } -/* If we fork, we no longer really own locks: preserves errno */ +/* If we fork, we no longer really own locks. */ static bool check_lock_pid(struct tdb_context *tdb, const char *call, bool log) { @@ -224,16 +224,14 @@ static enum TDB_ERROR tdb_brlock(struct tdb_context *tdb, static enum TDB_ERROR tdb_brunlock(struct tdb_context *tdb, int rw_type, tdb_off_t offset, size_t len) { - int ret; - if (tdb->flags & TDB_NOLOCK) { return TDB_SUCCESS; } - ret = unlock(tdb, rw_type, offset, len); + if (!check_lock_pid(tdb, "tdb_brunlock", true)) + return TDB_ERR_LOCK; - /* If we fail, *then* we verify that we owned the lock. If not, ok. */ - if (ret == -1 && check_lock_pid(tdb, "tdb_brunlock", false)) { + if (unlock(tdb, rw_type, offset, len) == -1) { return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR, "tdb_brunlock failed (fd=%d) at offset %zu" " rw_type=%d len=%zu: %s", @@ -851,6 +849,10 @@ void tdb_lock_cleanup(struct tdb_context *tdb) { unsigned int i; + /* We don't want to warn: they're allowed to close tdb after fork. */ + if (!check_lock_pid(tdb, "tdb_close", false)) + return; + while (tdb->file->allrecord_lock.count && tdb->file->allrecord_lock.owner == tdb) { tdb_allrecord_unlock(tdb, tdb->file->allrecord_lock.ltype); diff --git a/ccan/tdb2/test/run-fork-test.c b/ccan/tdb2/test/run-fork-test.c index ff1caa06..e9813e0a 100644 --- a/ccan/tdb2/test/run-fork-test.c +++ b/ccan/tdb2/test/run-fork-test.c @@ -85,10 +85,10 @@ int main(int argc, char *argv[]) return 2; tdb_chainunlock(tdb, key); - if (tap_log_messages != 2) + if (tap_log_messages != 3) return 3; tdb_close(tdb); - if (tap_log_messages != 2) + if (tap_log_messages != 3) return 4; return 0; } -- 2.39.2