diff options
| -rw-r--r-- | doc/doc-txt/ChangeLog | 10 | ||||
| -rw-r--r-- | src/src/daemon.c | 35 |
2 files changed, 35 insertions, 10 deletions
diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog index 03a41b4dd..f76f22a32 100644 --- a/doc/doc-txt/ChangeLog +++ b/doc/doc-txt/ChangeLog @@ -1,4 +1,4 @@ -$Cambridge: exim/doc/doc-txt/ChangeLog,v 1.22 2004/11/11 11:40:36 ph10 Exp $ +$Cambridge: exim/doc/doc-txt/ChangeLog,v 1.23 2004/11/11 16:03:47 ph10 Exp $ Change log file for Exim from version 4.21 ------------------------------------------- @@ -86,6 +86,14 @@ Exim version 4.44 since this list is usually IP addresses). A host name is now passed as "[x.x.x.x]". +24. Changed the calls that set up the SIGCHLD handler in the daemon to use the + code that specifies a non-restarting handler (typically sigaction() in + modern systems) in an attempt to fix a rare and obscure crash bug. + +25. Narrowed the window for a race in the daemon that could cause it to ignore + SIGCHLD signals. This is not a major problem, because they are used only to + wake it up if nothing else does. + Exim version 4.43 ----------------- diff --git a/src/src/daemon.c b/src/src/daemon.c index 19a8cea35..737d2ffe4 100644 --- a/src/src/daemon.c +++ b/src/src/daemon.c @@ -1,4 +1,4 @@ -/* $Cambridge: exim/src/src/daemon.c,v 1.2 2004/11/10 10:29:56 ph10 Exp $ */ +/* $Cambridge: exim/src/src/daemon.c,v 1.3 2004/11/11 16:03:47 ph10 Exp $ */ /************************************************* * Exim - an Internet mail transport agent * @@ -84,8 +84,8 @@ static void main_sigchld_handler(int sig) { sig = sig; /* Keep picky compilers happy */ +os_non_restarting_signal(SIGCHLD, SIG_DFL); sigchld_seen = TRUE; -signal(SIGCHLD, SIG_DFL); } @@ -1377,7 +1377,7 @@ if (queue_interval > 0 && queue_run_max > 0) /* Set up the handler for termination of child processes. */ sigchld_seen = FALSE; -signal(SIGCHLD, main_sigchld_handler); +os_non_restarting_signal(SIGCHLD, main_sigchld_handler); /* If we are to run the queue periodically, pretend the alarm has just gone off. This will cause the first queue-runner to get kicked off straight away. */ @@ -1624,17 +1624,34 @@ for (;;) } DEBUG(D_any) debug_printf("Listening...\n"); + + /* In rare cases we may have had a SIGCHLD signal in the time between + setting the handler (below) and getting back here. If so, pretend that the + select() was interrupted so that we reap the child. This might still leave + a small window when a SIGCHLD could get lost. However, since we use SIGCHLD + only to do the reaping more quickly, it shouldn't result in anything other + than a delay until something else causes a wake-up. */ + + if (sigchld_seen) + { + lcount = -1; + errno = EINTR; + } + else + { + lcount = select(max_socket + 1, (SELECT_ARG2_TYPE *)&select_listen, + NULL, NULL, NULL); + } - if ((lcount = select(max_socket + 1, (SELECT_ARG2_TYPE *)&select_listen, - NULL, NULL, NULL)) < 0) + if (lcount < 0) { select_failed = TRUE; lcount = 1; } - + /* Loop for all the sockets that are currently ready to go. If select - actually failed, we have set the count to 1 and a flag, so as to use the - common error code for select/accept below. */ + actually failed, we have set the count to 1 and select_failed=TRUE, so as + to use the common error code for select/accept below. */ while (lcount-- > 0) { @@ -1785,7 +1802,7 @@ for (;;) if (sigchld_seen) { sigchld_seen = FALSE; - signal(SIGCHLD, main_sigchld_handler); + os_non_restarting_signal(SIGCHLD, main_sigchld_handler); } /* Handle being woken by SIGHUP. We know at this point that the result |