irssibot
commented
11 years ago -
-
- Attachment 285 by @xkr47
-
patch
commit 7605b97cab3ec09cfc398a178cdff4d4c4da55fe
Author: Jonas Berlin <irssi@outerspace.dyndns.org>
Date: Wed Oct 24 22:59:35 2012
Avoid overriding our SIGTERM handler unless user explicitly wants
irssi to ignore the signal (non-WIN32 systems only).
The problem: although an signal handler was installed to simulate
"/quit" when SIGTERM is received, code executed later during startup
always got rid of the handler and thus /quit was never simulated on
SIGTERM.
As a result, the client always lost connections to servers in an
uncontrolled fashion when SIGTERM occured, probably resulting in
"Connection reset by peer" and similar quit messages. One "natural"
source of SIGTERM is when the machine running irssi is rebooted
without manually shutting down irssi first with the /quit command.
The situation inherits from core_init() which first calls
settings_init() which calls init_configfile() to set up the sigterm
handler. However, core_init() later calls read_settings() which on
non-WIN32 systems sets up a bunch of signals (including SIGTERM) to
either SIG_IGN or SIG_DFL depending on user preferences.
This patch changes read_settings() to retain the custom handler
instead of using SIG_DFL for SIGTERM. Therefore the user can still
choose to ignore SIGTERM, but when not the SIGTERM handler from
init_configfile() will be used. The other signals are set up as
before. It has also been implemented to work as expected when
dynamically changing the "ignore_signals" setting.
The patch thus enables irssi to shut down cleanly even when receiving
SIGTERM. This includes invoking any (perl) scripts that have hooked
onto the "quit" command using command_bind('quit', ...);
diff --git src/core/core.c src/core/core.c
index b9debbb..844a6ef 100644
--- src/core/core.c
+++ src/core/core.c
@@ -92,11 +92,17 @@ static void read_settings(void)
"int", "quit", "term",
"alrm", "usr1", "usr2"
};
+ static struct sigaction default_sigterm_handler;
const char *ignores;
struct sigaction act;
int n;
+ // remember default sigterm handler on first call
+ if (!default_sigterm_handler.sa_handler && !default_sigterm_handler.sa_sigaction) {
+ sigaction(SIGTERM, NULL, &default_sigterm_handler);
+ }
+
ignores = settings_get_str("ignore_signals");
sigemptyset (&act.sa_mask);
@@ -109,7 +115,13 @@ static void read_settings(void)
for (n = 0; n < sizeof(signals)/sizeof(signals[0]); n++) {
act.sa_handler = find_substr(ignores, signames[n]) ?
SIG_IGN : SIG_DFL;
- sigaction(signals[n], &act, NULL);
+
+ /* For SIGTERM replace SIG_DFL with the signal handler we installed earlier in settings.c */
+ if (signals[n] == SIGTERM && act.sa_handler == SIG_DFL) {
+ sigaction(SIGTERM, &default_sigterm_handler, NULL);
+ } else {
+ sigaction(signals[n], &act, NULL);
+ }
}
#ifdef HAVE_SYS_RESOURCE_H
The problem: although an signal handler was installed to simulate "/quit" when SIGTERM is received, code executed later during startup always got rid of the handler and thus /quit was never simulated on SIGTERM.
As a result, the client always lost connections to servers in an uncontrolled fashion when SIGTERM occured, probably resulting in "Connection reset by peer" and similar quit messages. One "natural" source of SIGTERM is when the machine running irssi is rebooted without manually shutting down irssi first with the /quit command.
The situation inherits from core_init() which first calls settings_init() which calls init_configfile() to set up the sigterm handler. However, core_init() later calls read_settings() which on non-WIN32 systems sets up a bunch of signals (including SIGTERM) to either SIG_IGN or SIG_DFL depending on user preferences.
The attached patch changes read_settings() to retain the custom handler instead of using SIG_DFL for SIGTERM. Therefore the user can still choose to ignore SIGTERM, but when not [ignoring] the SIGTERM handler from init_configfile() will be used. The other signals are set up as before. It has also been implemented to work as expected when dynamically changing the "ignore_signals" setting.
The patch thus enables irssi to shut down cleanly even when receiving SIGTERM. This includes invoking any (perl) scripts that have hooked onto the "quit" command using command_bind('quit', ...);