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Use ev_signal to avoid async-unsafe functions (Thanks Markus) 

Functions such as fprintf() might be unsafe to use in a signal handler,
see http://stackoverflow.com/questions/3941271/#answer-3941563

By using ev_signal, libev will use a tiny signal handler which just
passes on the information and then calls (outside of the signal handler)
our callback function which can use fprintf() and other unsafe
functions.

fixes #803
next
Michael Stapelberg 2012-09-21 16:35:25 +02:00
parent d638e3029a
commit 514265b529
1 changed files with 20 additions and 17 deletions
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37
src/main.c
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@ -232,13 +232,15 @@ static void i3_exit(void) {
* Unlinks the SHM log and re-raises the signal.
*
*/
static void handle_signal(int sig, siginfo_t *info, void *data) {
static void handle_signal(struct ev_loop *loop, ev_signal *w, int revents) {
int sig = w->signum;
fprintf(stderr, "Received signal %d, terminating\n", sig);
if (*shmlogname != '\0') {
fprintf(stderr, "Closing SHM log \"%s\"\n", shmlogname);
shm_unlink(shmlogname);
}
fflush(stderr);
ev_signal_stop(loop, w);
raise(sig);
}
@ -780,31 +782,32 @@ int main(int argc, char *argv[]) {
}
xcb_ungrab_server(conn);
struct sigaction action;
action.sa_sigaction = handle_signal;
action.sa_flags = SA_NODEFER | SA_RESETHAND | SA_SIGINFO;
sigemptyset(&action.sa_mask);
#define HANDLE_SIGNAL_EV(signum) \
do { \
struct ev_signal *signal_watcher = scalloc(sizeof(struct ev_signal)); \
ev_signal_init(signal_watcher, handle_signal, signum); \
ev_signal_start(main_loop, signal_watcher); \
} while (0)
if (!disable_signalhandler)
setup_signal_handler();
else {
/* Catch all signals with default action "Core", see signal(7) */
if (sigaction(SIGQUIT, &action, NULL) == -1 ||
sigaction(SIGILL, &action, NULL) == -1 ||
sigaction(SIGABRT, &action, NULL) == -1 ||
sigaction(SIGFPE, &action, NULL) == -1 ||
sigaction(SIGSEGV, &action, NULL) == -1)
ELOG("Could not setup signal handler");
HANDLE_SIGNAL_EV(SIGQUIT);
HANDLE_SIGNAL_EV(SIGILL);
HANDLE_SIGNAL_EV(SIGABRT);
HANDLE_SIGNAL_EV(SIGFPE);
HANDLE_SIGNAL_EV(SIGSEGV);
}
/* Catch all signals with default action "Term", see signal(7) */
if (sigaction(SIGHUP, &action, NULL) == -1 ||
sigaction(SIGINT, &action, NULL) == -1 ||
sigaction(SIGALRM, &action, NULL) == -1 ||
sigaction(SIGUSR1, &action, NULL) == -1 ||
sigaction(SIGUSR2, &action, NULL) == -1)
ELOG("Could not setup signal handler");
HANDLE_SIGNAL_EV(SIGHUP);
HANDLE_SIGNAL_EV(SIGINT);
HANDLE_SIGNAL_EV(SIGALRM);
HANDLE_SIGNAL_EV(SIGTERM);
HANDLE_SIGNAL_EV(SIGUSR1);
HANDLE_SIGNAL_EV(SIGUSR2);
/* Ignore SIGPIPE to survive errors when an IPC client disconnects
* while we are sending him a message */