From: Lars Schneider <larsxschneider@gmail.com>
To: Johannes Sixt <j6t@kdbg.org>
Cc: Git Mailing List <git@vger.kernel.org>,
gitster@pobox.com, jnareb@gmail.com, tboegi@web.de,
mlbright@gmail.com, e@80x24.org, peff@peff.net
Subject: Re: [PATCH v3 06/10] run-command: add clean_on_exit_handler
Date: Tue, 2 Aug 2016 09:41:11 +0200 [thread overview]
Message-ID: <1C660676-D19E-4F73-BDD9-5F18CC0245EA@gmail.com> (raw)
In-Reply-To: <c2a8149b-8a61-81d8-f07b-31b80e565fda@kdbg.org>
> On 02 Aug 2016, at 07:53, Johannes Sixt <j6t@kdbg.org> wrote:
>
> Am 01.08.2016 um 13:14 schrieb Lars Schneider:
> >> On 30 Jul 2016, at 11:50, Johannes Sixt <j6t@kdbg.org> wrote:
> >> Am 30.07.2016 um 01:37 schrieb larsxschneider@gmail.com:
> >>> static struct child_to_clean *children_to_clean;
> >>> @@ -30,6 +31,8 @@ static void cleanup_children(int sig, int in_signal)
> >>> {
> >>> while (children_to_clean) {
> >>> struct child_to_clean *p = children_to_clean;
> >>> + if (p->clean_on_exit_handler)
> >>> + p->clean_on_exit_handler(p->pid);
> >>
> >> This summons demons. cleanup_children() is invoked from a signal
> >> handler. In this case, it can call only async-signal-safe functions.
> >> It does not look like the handler that you are going to install
> >> later will take note of this caveat!
> >>
> >>> children_to_clean = p->next;
> >>> kill(p->pid, sig);
> >>> if (!in_signal)
> >>
> >> The condition that we see here in the context protects free(p)
> >> (which is not async-signal-safe). Perhaps the invocation of the new
> >> callback should be skipped in the same manner when this is called
> >> from a signal handler? 507d7804 (pager: don't use unsafe functions
> >> in signal handlers) may be worth a look.
> >
> > Thanks a lot of pointing this out to me!
> >
> > Do I get it right that after the signal "SIGTERM" I can do a cleanup
> > and don't need to worry about any function calls but if I get any
> > other signal then I can only perform async-signal-safe calls?
>
> No. SIGTERM is not special.
>
> Perhaps you were misled by the SIGTERM mentioned in cleanup_children_on_exit()? This function is invoked on regular exit (not from a signal). SIGTERM is used in this case to terminate children that are still lingering around.
Yes, that was my source of confusion. Thanks for the clarification!
>
> > If this is correct, then the following solution would work great:
> >
> > if (!in_signal && p->clean_on_exit_handler)
> > p->clean_on_exit_handler(p->pid);
>
> This should work nevertheless because in_signal is set when the function is invoked from a signal handler (of any signal that is caught) via cleanup_children_on_signal().
Right. Thank you!
- Lars
next prev parent reply other threads:[~2016-08-02 7:59 UTC|newest]
Thread overview: 120+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20160727000605.49982-1-larsxschneider%40gmail.com/>
2016-07-29 23:37 ` [PATCH v3 00/10] Git filter protocol larsxschneider
2016-07-29 23:37 ` [PATCH v3 01/10] pkt-line: extract set_packet_header() larsxschneider
2016-07-30 10:30 ` Jakub Narębski
2016-08-01 11:33 ` Lars Schneider
2016-08-03 20:05 ` Jakub Narębski
2016-08-05 11:52 ` Lars Schneider
2016-07-29 23:37 ` [PATCH v3 02/10] pkt-line: add direct_packet_write() and direct_packet_write_data() larsxschneider
2016-07-30 10:49 ` Jakub Narębski
2016-08-01 12:00 ` Lars Schneider
2016-08-03 20:12 ` Jakub Narębski
2016-08-05 12:02 ` Lars Schneider
2016-07-29 23:37 ` [PATCH v3 03/10] pkt-line: add packet_flush_gentle() larsxschneider
2016-07-30 12:04 ` Jakub Narębski
2016-08-01 12:28 ` Lars Schneider
2016-07-31 20:36 ` Torstem Bögershausen
2016-07-31 21:45 ` Lars Schneider
2016-08-02 19:56 ` Torsten Bögershausen
2016-08-05 9:59 ` Lars Schneider
2016-07-29 23:37 ` [PATCH v3 04/10] pkt-line: call packet_trace() only if a packet is actually send larsxschneider
2016-07-30 12:29 ` Jakub Narębski
2016-08-01 12:18 ` Lars Schneider
2016-08-03 20:15 ` Jakub Narębski
2016-07-29 23:37 ` [PATCH v3 05/10] pack-protocol: fix maximum pkt-line size larsxschneider
2016-07-30 13:58 ` Jakub Narębski
2016-08-01 12:23 ` Lars Schneider
2016-07-29 23:37 ` [PATCH v3 06/10] run-command: add clean_on_exit_handler larsxschneider
2016-07-30 9:50 ` Johannes Sixt
2016-08-01 11:14 ` Lars Schneider
2016-08-02 5:53 ` Johannes Sixt
2016-08-02 7:41 ` Lars Schneider [this message]
2016-07-29 23:37 ` [PATCH v3 07/10] convert: quote filter names in error messages larsxschneider
2016-07-29 23:37 ` [PATCH v3 08/10] convert: modernize tests larsxschneider
2016-07-29 23:38 ` [PATCH v3 09/10] convert: generate large test files only once larsxschneider
2016-07-29 23:38 ` [PATCH v3 10/10] convert: add filter.<driver>.process option larsxschneider
2016-07-30 22:05 ` Jakub Narębski
2016-07-31 9:42 ` Jakub Narębski
2016-07-31 19:49 ` Lars Schneider
2016-07-31 22:59 ` Jakub Narębski
2016-08-01 13:32 ` Lars Schneider
2016-08-03 18:30 ` Designing the filter process protocol (was: Re: [PATCH v3 10/10] convert: add filter.<driver>.process option) Jakub Narębski
2016-08-05 10:32 ` Lars Schneider
2016-08-06 18:24 ` Lars Schneider
2016-08-03 22:47 ` [PATCH v3 10/10] convert: add filter.<driver>.process option Jakub Narębski
2016-07-31 22:19 ` Jakub Narębski
2016-08-01 17:55 ` Lars Schneider
2016-08-04 0:42 ` Jakub Narębski
2016-08-03 13:10 ` Lars Schneider
2016-08-04 10:18 ` Jakub Narębski
2016-08-05 13:20 ` Lars Schneider
2016-08-03 16:42 ` [PATCH v4 00/12] Git filter protocol larsxschneider
2016-08-03 16:42 ` [PATCH v4 01/12] pkt-line: extract set_packet_header() larsxschneider
2016-08-03 20:18 ` Junio C Hamano
2016-08-03 21:12 ` Jeff King
2016-08-03 21:27 ` Jeff King
2016-08-04 16:14 ` Junio C Hamano
2016-08-05 14:55 ` Lars Schneider
2016-08-05 16:31 ` Junio C Hamano
2016-08-05 17:31 ` Lars Schneider
2016-08-05 17:41 ` Junio C Hamano
2016-08-03 21:56 ` Lars Schneider
2016-08-03 16:42 ` [PATCH v4 02/12] pkt-line: add direct_packet_write() and direct_packet_write_data() larsxschneider
2016-08-03 16:42 ` [PATCH v4 03/12] pkt-line: add packet_flush_gentle() larsxschneider
2016-08-03 21:39 ` Jeff King
2016-08-03 22:56 ` [PATCH 0/7] minor trace fixes and cosmetic improvements Jeff King
2016-08-03 22:56 ` [PATCH 1/7] trace: handle NULL argument in trace_disable() Jeff King
2016-08-03 22:58 ` [PATCH 2/7] trace: stop using write_or_whine_pipe() Jeff King
2016-08-03 22:58 ` [PATCH 3/7] trace: use warning() for printing trace errors Jeff King
2016-08-04 20:41 ` Junio C Hamano
2016-08-04 21:21 ` Jeff King
2016-08-04 21:28 ` Junio C Hamano
2016-08-05 7:56 ` Jeff King
2016-08-05 7:59 ` Christian Couder
2016-08-05 18:41 ` Junio C Hamano
2016-08-03 23:00 ` [PATCH 4/7] trace: cosmetic fixes for error messages Jeff King
2016-08-04 20:42 ` Junio C Hamano
2016-08-05 8:00 ` Jeff King
2016-08-03 23:00 ` [PATCH 5/7] trace: correct variable name in write() error message Jeff King
2016-08-03 23:01 ` [PATCH 6/7] trace: disable key after write error Jeff King
2016-08-04 20:45 ` Junio C Hamano
2016-08-04 21:22 ` Jeff King
2016-08-05 7:58 ` Jeff King
2016-08-03 23:01 ` [PATCH 7/7] write_or_die: drop write_or_whine_pipe() Jeff King
2016-08-03 23:04 ` [PATCH 0/7] minor trace fixes and cosmetic improvements Jeff King
2016-08-04 16:16 ` [PATCH v4 03/12] pkt-line: add packet_flush_gentle() Junio C Hamano
2016-08-03 16:42 ` [PATCH v4 04/12] pkt-line: call packet_trace() only if a packet is actually send larsxschneider
2016-08-03 16:42 ` [PATCH v4 05/12] pkt-line: add functions to read/write flush terminated packet streams larsxschneider
2016-08-03 16:42 ` [PATCH v4 06/12] pack-protocol: fix maximum pkt-line size larsxschneider
2016-08-03 16:42 ` [PATCH v4 07/12] run-command: add clean_on_exit_handler larsxschneider
2016-08-03 21:24 ` Jeff King
2016-08-03 22:15 ` Lars Schneider
2016-08-03 22:53 ` Jeff King
2016-08-03 23:09 ` Lars Schneider
2016-08-03 23:15 ` Jeff King
2016-08-05 13:08 ` Lars Schneider
2016-08-05 21:19 ` Torsten Bögershausen
2016-08-05 21:50 ` Lars Schneider
2016-08-03 16:42 ` [PATCH v4 08/12] convert: quote filter names in error messages larsxschneider
2016-08-03 16:42 ` [PATCH v4 09/12] convert: modernize tests larsxschneider
2016-08-03 16:42 ` [PATCH v4 10/12] convert: generate large test files only once larsxschneider
2016-08-03 16:42 ` [PATCH v4 11/12] convert: add filter.<driver>.process option larsxschneider
2016-08-03 17:45 ` Junio C Hamano
2016-08-03 21:48 ` Lars Schneider
2016-08-03 22:46 ` Jeff King
2016-08-05 12:53 ` Lars Schneider
2016-08-03 20:29 ` Junio C Hamano
2016-08-03 21:37 ` Lars Schneider
2016-08-03 21:43 ` Junio C Hamano
2016-08-03 22:01 ` Lars Schneider
2016-08-05 21:34 ` Torsten Bögershausen
2016-08-05 21:49 ` Lars Schneider
2016-08-05 22:06 ` Junio C Hamano
2016-08-05 22:27 ` Jeff King
2016-08-06 11:55 ` Lars Schneider
2016-08-06 12:14 ` Jeff King
2016-08-06 18:19 ` Lars Schneider
2016-08-08 15:02 ` Jeff King
2016-08-08 16:21 ` Lars Schneider
2016-08-08 16:26 ` Jeff King
2016-08-06 20:40 ` Torsten Bögershausen
2016-08-03 16:42 ` [PATCH v4 12/12] convert: add filter.<driver>.process shutdown command option larsxschneider
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