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/*
* Signal handlers
*/
#include "ctwm.h"
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "ctwm_shutdown.h"
#include "signals.h"
/* Our backends */
static void sh_restart(int signum);
static void sh_shutdown(int signum);
// Internal flags for which signals have called us
static bool sig_restart = false;
static bool sig_shutdown = false;
// External flag for whether some signal handler has set a flag that
// needs to trigger an action.
bool SignalFlag = false;
/**
* Setup signal handlers (run during startup)
*/
void
setup_signal_handlers(void)
{
// INT/QUIT/TERM: shutdown
// XXX Wildly unsafe handler; to be reworked
signal(SIGINT, sh_shutdown);
signal(SIGQUIT, sh_shutdown);
signal(SIGTERM, sh_shutdown);
// SIGHUP: restart
signal(SIGHUP, sh_restart);
// We don't use alarm(), but if we get the stray signal we shouldn't
// die...
signal(SIGALRM, SIG_IGN);
// This should be set by default, but just in case; explicitly don't
// leave zombies.
signal(SIGCHLD, SIG_IGN);
return;
}
/**
* Handle stuff set by a signal flag. Could be a Restart, could be a
* Shutdown...
*/
void
handle_signal_flag(Time t)
{
// Restarting?
if(sig_restart) {
// In case it fails, don't loop
sig_restart = false;
// Handle
DoRestart(t);
// Shouldn't return, but exec() might fail...
return;
}
// Shutting down?
if(sig_shutdown) {
// Doit
DoShutdown();
// Can't return!
fprintf(stderr, "%s: DoShutdown() shouldn't return!\n", ProgramName);
exit(1);
}
// ???
fprintf(stderr, "%s: Internal error: unexpected signal flag.\n",
ProgramName);
return;
}
/*
* Internal backend bits
*/
/**
* Set flag to restart. Backend for SIGHUP.
*/
static void
sh_restart(int signum)
{
// Signal handler; stdio isn't async-signal-safe, write(2) is
const char srf[] = ": signal received, setting restart flag\n";
write(2, ProgramName, ProgramNameLen);
write(2, srf, sizeof(srf));
SignalFlag = sig_restart = true;
}
/**
* Set flag to shutdown. Backend for SIGTERM etc.
*/
static void
sh_shutdown(int signum)
{
// Signal handler; stdio isn't async-signal-safe, write(2) is
const char srf[] = ": signal received, setting shutdown flag\n";
write(2, ProgramName, ProgramNameLen);
write(2, srf, sizeof(srf));
SignalFlag = sig_shutdown = true;
}
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