From 71fbf9366442ff06f50b3a6f5f48c0e95ec920fb Mon Sep 17 00:00:00 2001 From: Stefan Metzmacher Date: Thu, 1 Apr 2010 16:23:06 +0200 Subject: [PATCH] s3:winbindd: fix problems with SIGCHLD handling (bug #7317) The main problem is that we call CatchChild() within the parent winbindd, which overwrites the signal handler that was registered by winbindd_setup_sig_chld_handler(). That means winbindd_sig_chld_handler() and winbind_child_died() are never triggered when a winbindd domain child dies. As a result will get "broken pipe" for all requests to that domain. To reduce the risk of similar bugs in future we call CatchChild() in winbindd_reinit_after_fork() now. We also use a full winbindd_reinit_after_fork() in the cache validation child now instead instead of just resetting the SIGCHLD handler by hand. This will also fix possible tdb problems on systems without pread/pwrite and disabled mmap as we now correctly reopen the tdb handle for the child. metze (cherry picked from commit 73577205cf81644e7fe853eaf3e6459f7f443096) --- source3/winbindd/winbindd.c | 14 +++----------- source3/winbindd/winbindd_cm.c | 3 --- source3/winbindd/winbindd_dual.c | 6 +++--- 3 files changed, 6 insertions(+), 17 deletions(-) diff --git a/source3/winbindd/winbindd.c b/source3/winbindd/winbindd.c index 9684a34..6e02b7d 100644 --- a/source3/winbindd/winbindd.c +++ b/source3/winbindd/winbindd.c @@ -384,7 +384,6 @@ static void winbind_msg_validate_cache(struct messaging_context *msg_ctx, * so we don't block the main winbindd and the validation * code can safely use fork/waitpid... */ - CatchChild(); child_pid = sys_fork(); if (child_pid == -1) { @@ -402,16 +401,9 @@ static void winbind_msg_validate_cache(struct messaging_context *msg_ctx, /* child */ - /* install default SIGCHLD handler: validation code uses fork/waitpid */ - ZERO_STRUCT(act); - act.sa_handler = SIG_DFL; -#ifdef SA_RESTART - /* We *want* SIGALRM to interrupt a system call. */ - act.sa_flags = SA_RESTART; -#endif - sigemptyset(&act.sa_mask); - sigaddset(&act.sa_mask,SIGCHLD); - sigaction(SIGCHLD,&act,&oldact); + if (!winbindd_reinit_after_fork(NULL)) { + _exit(0); + } ret = (uint8)winbindd_validate_cache_nobackup(); DEBUG(10, ("winbindd_msg_validata_cache: got return value %d\n", ret)); diff --git a/source3/winbindd/winbindd_cm.c b/source3/winbindd/winbindd_cm.c index e43a431..66da35f 100644 --- a/source3/winbindd/winbindd_cm.c +++ b/source3/winbindd/winbindd_cm.c @@ -179,9 +179,6 @@ static bool fork_child_dc_connect(struct winbindd_domain *domain) pid_t parent_pid = sys_getpid(); char *lfile = NULL; - /* Stop zombies */ - CatchChild(); - if (domain->dc_probe_pid != (pid_t)-1) { /* * We might already have a DC probe diff --git a/source3/winbindd/winbindd_dual.c b/source3/winbindd/winbindd_dual.c index dff9652..291b2d1 100644 --- a/source3/winbindd/winbindd_dual.c +++ b/source3/winbindd/winbindd_dual.c @@ -1219,6 +1219,9 @@ bool winbindd_reinit_after_fork(const char *logfilename) logfilename)) return false; + /* Stop zombies in children */ + CatchChild(); + /* Don't handle the same messages as our parent. */ messaging_deregister(winbind_messaging_context(), MSG_SMB_CONF_UPDATED, NULL); @@ -1342,9 +1345,6 @@ static bool fork_domain_child(struct winbindd_child *child) DEBUG(10, ("Child process %d\n", (int)sys_getpid())); - /* Stop zombies in children */ - CatchChild(); - state.sock = fdpair[0]; close(fdpair[1]); -- 1.6.3.3