From 4a16d072723b48699ea162da24eff05eba298834 Mon Sep 17 00:00:00 2001 From: Jeff King Date: Thu, 22 Jan 2009 01:02:35 -0500 Subject: chain kill signals for cleanup functions If a piece of code wanted to do some cleanup before exiting (e.g., cleaning up a lockfile or a tempfile), our usual strategy was to install a signal handler that did something like this: do_cleanup(); /* actual work */ signal(signo, SIG_DFL); /* restore previous behavior */ raise(signo); /* deliver signal, killing ourselves */ For a single handler, this works fine. However, if we want to clean up two _different_ things, we run into a problem. The most recently installed handler will run, but when it removes itself as a handler, it doesn't put back the first handler. This patch introduces sigchain, a tiny library for handling a stack of signal handlers. You sigchain_push each handler, and use sigchain_pop to restore whoever was before you in the stack. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano --- http-push.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) (limited to 'http-push.c') diff --git a/http-push.c b/http-push.c index a4b7d08663..dec395deed 100644 --- a/http-push.c +++ b/http-push.c @@ -10,6 +10,7 @@ #include "exec_cmd.h" #include "remote.h" #include "list-objects.h" +#include "sigchain.h" #include @@ -1363,7 +1364,7 @@ static void remove_locks(void) static void remove_locks_on_signal(int signo) { remove_locks(); - signal(signo, SIG_DFL); + sigchain_pop(signo); raise(signo); } @@ -2261,10 +2262,10 @@ int main(int argc, char **argv) goto cleanup; } - signal(SIGINT, remove_locks_on_signal); - signal(SIGHUP, remove_locks_on_signal); - signal(SIGQUIT, remove_locks_on_signal); - signal(SIGTERM, remove_locks_on_signal); + sigchain_push(SIGINT, remove_locks_on_signal); + sigchain_push(SIGHUP, remove_locks_on_signal); + sigchain_push(SIGQUIT, remove_locks_on_signal); + sigchain_push(SIGTERM, remove_locks_on_signal); /* Check whether the remote has server info files */ remote->can_update_info_refs = 0; -- cgit v1.3