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 --- builtin-fetch.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'builtin-fetch.c') diff --git a/builtin-fetch.c b/builtin-fetch.c index de6f3074b1..8c86974cbe 100644 --- a/builtin-fetch.c +++ b/builtin-fetch.c @@ -10,6 +10,7 @@ #include "transport.h" #include "run-command.h" #include "parse-options.h" +#include "sigchain.h" static const char * const builtin_fetch_usage[] = { "git fetch [options] [ ...]", @@ -58,7 +59,7 @@ static void unlock_pack(void) static void unlock_pack_on_signal(int signo) { unlock_pack(); - signal(SIGINT, SIG_DFL); + sigchain_pop(signo); raise(signo); } @@ -672,7 +673,7 @@ int cmd_fetch(int argc, const char **argv, const char *prefix) ref_nr = j; } - signal(SIGINT, unlock_pack_on_signal); + sigchain_push(SIGINT, unlock_pack_on_signal); atexit(unlock_pack); exit_code = do_fetch(transport, parse_fetch_refspec(ref_nr, refs), ref_nr); -- cgit v1.2.1