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 <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-01-22 09:02:35 +03:00
|
|
|
#include "cache.h"
|
2014-09-14 11:40:45 +04:00
|
|
|
#include "sigchain.h"
|
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 <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-01-22 09:02:35 +03:00
|
|
|
|
|
|
|
|
#define X(f) \
|
|
|
|
|
static void f(int sig) { \
|
|
|
|
|
puts(#f); \
|
|
|
|
|
fflush(stdout); \
|
|
|
|
|
sigchain_pop(sig); \
|
|
|
|
|
raise(sig); \
|
|
|
|
|
}
|
|
|
|
|
X(one)
|
|
|
|
|
X(two)
|
|
|
|
|
X(three)
|
|
|
|
|
#undef X
|
|
|
|
|
|
|
|
|
|
int main(int argc, char **argv) {
|
2009-01-30 11:21:01 +03:00
|
|
|
sigchain_push(SIGTERM, one);
|
|
|
|
|
sigchain_push(SIGTERM, two);
|
|
|
|
|
sigchain_push(SIGTERM, three);
|
|
|
|
|
raise(SIGTERM);
|
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 <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-01-22 09:02:35 +03:00
|
|
|
return 0;
|
|
|
|
|
}
|
