ksh93 is known to report $? of programs that terminated by a signal as
256 + signal number instead of 128 + signal number like other POSIX
compliant shells (ksh's behavior is still POSIX compliant in this regard).
Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The signal tests consists of checking that each of our
handlers is executed, and that the test program was killed
by the final signal. We arbitrarily used SIGINT as the kill
signal.
However, some platforms (notably Solaris) will default
SIGINT to SIG_IGN if there is no controlling terminal. In
that case, we don't end up killing the program with the
final signal and the test fails.
This is a problem since the test script should not depend
on outside factors; let's use SIGTERM instead, which should
behave consistently.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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>
