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Defer SIGTERM/SIGINT shutdown out of the signal handler #1925

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Defer SIGTERM/SIGINT shutdown out of the signal handler #1925

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37 changes: 29 additions & 8 deletions src/main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -121,9 +121,10 @@ int notify_users_at = 0; /* Minutes past the hour to notify users of notes? */
char version[128]; /* Version info (long form) */
char ver[41]; /* Version info (short form) */

volatile sig_atomic_t do_restart = 0; /* .restart has been called, restart ASAP */
int resolve_timeout = RES_TIMEOUT; /* Hostname/address lookup timeout */
char quit_msg[1024]; /* Quit message */
volatile sig_atomic_t do_restart = 0; /* .restart has been called, restart ASAP */
static volatile sig_atomic_t do_die = 0; /* SIGTERM/SIGINT received, die ASAP */
int resolve_timeout = RES_TIMEOUT; /* Hostname/address lookup timeout */
char quit_msg[1024]; /* Quit message */

/* Moved here for n flag warning, put back in do_arg if removed */
unsigned char cliflags = 0;
Expand Down Expand Up @@ -365,12 +366,18 @@ static void got_fpe(int z)

static void got_term(int z)
{
/* Now we die by default on sigterm, but scripts have the chance to
* catch the event themselves and cancel shutdown by returning 1
/* Shutting down mid-mainloop from a signal handler is not safe (the
* signal can arrive while the heap or the user list is in an
* inconsistent state), so just flag it and let mainloop() do the work.
*/
if (check_tcl_signal("sigterm"))
return;
kill_bot("ACK, I've been terminated!", "TERMINATE SIGNAL -- SIGNING OFF");
if (do_die) {
/* Second signal while the first is still pending or shutdown is
* already in progress: the bot is probably hung, so die immediately
* without cleanup.
*/
_exit(1);
}
do_die = 1;
}

static void got_quit(int z)
Expand Down Expand Up @@ -730,6 +737,20 @@ static void mainloop(int toplevel)
*/
now = time(NULL);

/* SIGTERM or SIGINT was received. We die by default, but scripts have
* the chance to catch the event themselves and cancel shutdown by
* returning 1.
*/
if (do_die) {
/* Leave do_die set while shutting down, so a repeated signal still
* forces an immediate exit if the sigterm bind or the cleanup hangs.
*/
if (check_tcl_signal("sigterm"))
do_die = 0;
else
kill_bot("ACK, I've been terminated!", "TERMINATE SIGNAL -- SIGNING OFF");
}

/* If we want to restart, we have to unwind to the toplevel.
* Tcl will Panic if we kill the interp with Tcl_Eval in progress.
* This is done by returning -1 in tickle_WaitForEvent.
Expand Down
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