~ctwm/ctwm/trunk : contents of signals.c at revision 700.1.7

~ctwm/ctwm/trunk : (revision 700.1.7)

647.1.7 by Matthew Fuller Start splitting out signal handlers and their setup into their own	1	/*
	2	* Signal handlers
	3	*/
	4
	5	#include "ctwm.h"
	6
	7	#include <signal.h>
647.1.10 by Matthew Fuller Replace the direct Done() call with a flag for signal handling, so we	8	#include <stdio.h>
	9	#include <stdlib.h>
	10	#include <unistd.h>
647.1.7 by Matthew Fuller Start splitting out signal handlers and their setup into their own	11
648.1.1 by Matthew Fuller Extract the funcs relating to shutting down ctwm ('restart' is a kind	12	#include "ctwm_shutdown.h"
647.1.7 by Matthew Fuller Start splitting out signal handlers and their setup into their own	13	#include "signals.h"
	14
	15
	16	/* Our backends */
	17	static void sh_restart(int signum);
647.1.10 by Matthew Fuller Replace the direct Done() call with a flag for signal handling, so we	18	static void sh_shutdown(int signum);
647.1.7 by Matthew Fuller Start splitting out signal handlers and their setup into their own	19
	20
647.1.9 by Matthew Fuller Now we can localize the flag for "want to restart" into a static var	21	// Internal flags for which signals have called us
	22	static bool sig_restart = false;
647.1.10 by Matthew Fuller Replace the direct Done() call with a flag for signal handling, so we	23	static bool sig_shutdown = false;
647.1.9 by Matthew Fuller Now we can localize the flag for "want to restart" into a static var	24
647.1.12 by Matthew Fuller Might as well move this var over here now too.	25	// External flag for whether some signal handler has set a flag that
	26	// needs to trigger an action.
	27	bool SignalFlag = false;
	28
647.1.9 by Matthew Fuller Now we can localize the flag for "want to restart" into a static var	29
647.1.7 by Matthew Fuller Start splitting out signal handlers and their setup into their own	30	/**
	31	* Setup signal handlers (run during startup)
	32	*/
	33	void
	34	setup_signal_handlers(void)
	35	{
	36	// INT/QUIT/TERM: shutdown
	37	// XXX Wildly unsafe handler; to be reworked
647.1.10 by Matthew Fuller Replace the direct Done() call with a flag for signal handling, so we	38	signal(SIGINT, sh_shutdown);
	39	signal(SIGQUIT, sh_shutdown);
	40	signal(SIGTERM, sh_shutdown);
647.1.7 by Matthew Fuller Start splitting out signal handlers and their setup into their own	41
	42	// SIGHUP: restart
	43	signal(SIGHUP, sh_restart);
	44
	45	// We don't use alarm(), but if we get the stray signal we shouldn't
	46	// die...
	47	signal(SIGALRM, SIG_IGN);
	48
	49	// This should be set by default, but just in case; explicitly don't
	50	// leave zombies.
	51	signal(SIGCHLD, SIG_IGN);
	52
	53	return;
	54	}
	55
	56
647.1.8 by Matthew Fuller Use a more general "signal recvd" flag in place of the specific	57	/**
	58	* Handle stuff set by a signal flag. Could be a Restart, could be a
	59	* Shutdown...
	60	*/
	61	void
	62	handle_signal_flag(Time t)
	63	{
647.1.10 by Matthew Fuller Replace the direct Done() call with a flag for signal handling, so we	64	// Restarting?
647.1.9 by Matthew Fuller Now we can localize the flag for "want to restart" into a static var	65	if(sig_restart) {
	66	// In case it fails, don't loop
	67	sig_restart = false;
	68
	69	// Handle
647.1.8 by Matthew Fuller Use a more general "signal recvd" flag in place of the specific	70	DoRestart(t);
647.1.9 by Matthew Fuller Now we can localize the flag for "want to restart" into a static var	71
647.1.8 by Matthew Fuller Use a more general "signal recvd" flag in place of the specific	72	// Shouldn't return, but exec() might fail...
	73	return;
	74	}
647.1.10 by Matthew Fuller Replace the direct Done() call with a flag for signal handling, so we	75
	76	// Shutting down?
	77	if(sig_shutdown) {
	78	// Doit
648.1.19 by Matthew Fuller Done() -> DoShutdown(). Imperative form is more descriptive, and it's	79	DoShutdown();
647.1.10 by Matthew Fuller Replace the direct Done() call with a flag for signal handling, so we	80
	81	// Can't return!
648.1.19 by Matthew Fuller Done() -> DoShutdown(). Imperative form is more descriptive, and it's	82	fprintf(stderr, "%s: DoShutdown() shouldn't return!\n", ProgramName);
647.1.10 by Matthew Fuller Replace the direct Done() call with a flag for signal handling, so we	83	exit(1);
	84	}
	85
	86	// ???
	87	fprintf(stderr, "%s: Internal error: unexpected signal flag.\n",
648.1.7 by Matthew Fuller make indent	88	ProgramName);
647.1.10 by Matthew Fuller Replace the direct Done() call with a flag for signal handling, so we	89	return;
647.1.8 by Matthew Fuller Use a more general "signal recvd" flag in place of the specific	90	}
	91
	92
647.1.7 by Matthew Fuller Start splitting out signal handlers and their setup into their own	93
	94	/*
	95	* Internal backend bits
	96	*/
	97
	98	/**
	99	* Set flag to restart. Backend for SIGHUP.
	100	*/
	101	static void
	102	sh_restart(int signum)
	103	{
	104	// Signal handler; stdio isn't async-signal-safe, write(2) is
	105	const char srf[] = ": signal received, setting restart flag\n";
	106	write(2, ProgramName, ProgramNameLen);
	107	write(2, srf, sizeof(srf));
647.1.8 by Matthew Fuller Use a more general "signal recvd" flag in place of the specific	108
647.1.9 by Matthew Fuller Now we can localize the flag for "want to restart" into a static var	109	SignalFlag = sig_restart = true;
647.1.7 by Matthew Fuller Start splitting out signal handlers and their setup into their own	110	}
647.1.10 by Matthew Fuller Replace the direct Done() call with a flag for signal handling, so we	111
	112	/**
	113	* Set flag to shutdown. Backend for SIGTERM etc.
	114	*/
	115	static void
	116	sh_shutdown(int signum)
	117	{
	118	// Signal handler; stdio isn't async-signal-safe, write(2) is
	119	const char srf[] = ": signal received, setting shutdown flag\n";
	120	write(2, ProgramName, ProgramNameLen);
	121	write(2, srf, sizeof(srf));
	122
	123	SignalFlag = sig_shutdown = true;
	124	}
	125