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 --- diff.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'diff.c') diff --git a/diff.c b/diff.c index 3cfc0b636c..9c9977d892 100644 --- a/diff.c +++ b/diff.c @@ -12,6 +12,7 @@ #include "run-command.h" #include "utf8.h" #include "userdiff.h" +#include "sigchain.h" #ifdef NO_FAST_WORKING_DIRECTORY #define FAST_WORKING_DIRECTORY 0 @@ -188,7 +189,7 @@ static void remove_tempfile(void) static void remove_tempfile_on_signal(int signo) { remove_tempfile(); - signal(SIGINT, SIG_DFL); + sigchain_pop(signo); raise(signo); } @@ -1902,7 +1903,7 @@ static struct diff_tempfile *prepare_temp_file(const char *name, if (!remove_tempfile_installed) { atexit(remove_tempfile); - signal(SIGINT, remove_tempfile_on_signal); + sigchain_push(SIGINT, remove_tempfile_on_signal); remove_tempfile_installed = 1; } -- cgit v1.2.1