The first test already uses this more portable construct
(that was where it was factored from initially), but the
later tests do a raw comparison against 141 to look for
SIGPIPE, which can fail on some shells and platforms.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In POSIX shells, a program which exits due to a signal
generally has an exit code of 128 plus the signal number.
However, ksh uses 256 plus the signal number. We've
accounted for that in t0005, but not in other tests. Let's
pull out the logic so we can use it elsewhere.
It would be nice for debugging if this additionally printed
errors to stderr, like our other test_* helpers. But we're
going to need to use it in other places besides the innards
of a test_expect block. So let's leave it as generic as
possible.
Note that we also leave the magic "3" for Windows out of the
generic helper. This is an artifact of the way we use
raise() to kill ourselves in test-sigchain.c, and will not
necessarily apply to all programs. So it's better to keep it
out of the helper, to reduce the chance of confusing it with
a real call to exit(3).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The ":" noop command always returns true, so it is fine to
include these lines in an &&-chain (and it appeases
--chain-lint).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If we are expecting a command to produce a particular exit
code, we can use test_expect_code. However, some cases are
more complicated, and want to accept one of a range of exit
codes. For these, we end up with something like:
cmd;
case "$?" in
...
That unfortunately breaks the &&-chain and fools
--chain-lint. Since these special cases are so few, we can
wrap them in a block, like this:
{ cmd; ret=$?; } &&
case "$ret" in
...
This accomplishes the same thing, and retains the &&-chain
(the exit status fed to the && is that of the assignment,
which should always be true). It's technically longer, but
it is probably a good thing for unusual code like this to
stand out.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Windows does not have POSIX-like signals, and so we ignore all
operations on the non-existent signal mask machinery.
Do not turn sigemptyset into a function, but leave it a macro that
erases the code in the argument because it is used to set sa_mask
of a struct sigaction, but our dummy in mingw.h does not have that
member.
Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Blocked and ignored signals -- but not caught signals -- are inherited
across exec. Some callers with sloppy signal-handling behavior can call
git with SIGPIPE blocked or ignored, even non-deterministically. When
SIGPIPE is blocked or ignored, several git commands can run indefinitely,
ignoring EPIPE returns from write() calls, even when the process that
called them has gone away. Our specific case involved a pipe of git
diff-tree output to a script that reads a limited amount of diff data.
In an ideal world, git would never be called with SIGPIPE blocked or
ignored. But in the real world, several real potential callers, including
Perl, Apache, and Unicorn, sometimes spawn subprocesses with SIGPIPE
ignored. It is easier and more productive to harden git against this
mistake than to clean it up in every potential parent process.
Signed-off-by: Patrick Reynolds <patrick.reynolds@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The test case depends on that test-sigchain can commit suicide by a
call to raise(SIGTERM) in a way that run-command.c::wait_or_whine()
can detect as death through a signal. There are no POSIX signals on
Windows, and a sufficiently close emulation is not available in the
Microsoft C runtime (and probably not even possible).
The particular deficiency is that when a signal is raise()d whose
SIG_DFL action will cause process death (SIGTERM in this case), the
implementation of raise() in msvcrt just calls exit(3).
We could check for exit code 3 in addition to 143, but that would
miss the point of the test entirely. Hence, just skip it on Windows.
Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When a sub-process dies with a signal, we convert the exit
code to the shell convention of 128+sig. Callers of git may
be relying on this behavior, so let's make sure it does not
break.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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>
Jeff King
Johannes Sixt
Patrick Reynolds