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signal handler: set flag because directly calling fprintf() is unsafe

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This commit is contained in:
Michael Stapelberg 2013-05-19 19:58:51 +02:00
parent 7a372b0f46
commit 3beb6b4406
1 changed files with 16 additions and 7 deletions
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23
i3status.c
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@ -45,19 +45,19 @@
/* socket file descriptor for general purposes */
int general_socket;
static bool exit_upon_signal = false;
cfg_t *cfg, *cfg_general, *cfg_section;
/*
* Exit upon SIGPIPE because when we have nowhere to write to, gathering system
* information is pointless. Also exit explicitly on SIGTERM and SIGINT because
* only this will trigger a reset of the cursor in the terminal output-format.
* Set the exit_upon_signal flag, because one cannot do anything in a safe
* manner in a signal handler (e.g. fprintf, which we really want to do for
* debugging purposes), see
* https://www.securecoding.cert.org/confluence/display/seccode/SIG30-C.+Call+only+asynchronous-safe+functions+within+signal+handlers
*
*/
void fatalsig(int signum) {
fprintf(stderr, "Received SIG%s, exiting\n", signum == SIGPIPE ? "PIPE" :
signum == SIGTERM ? "TERM" :
"INT");
exit(1);
exit_upon_signal = true;
}
/*
@ -325,6 +325,11 @@ int main(int argc, char *argv[]) {
struct sigaction action;
memset(&action, 0, sizeof(struct sigaction));
action.sa_handler = fatalsig;
/* Exit upon SIGPIPE because when we have nowhere to write to, gathering system
* information is pointless. Also exit explicitly on SIGTERM and SIGINT because
* only this will trigger a reset of the cursor in the terminal output-format.
*/
sigaction(SIGPIPE, &action, NULL);
sigaction(SIGTERM, &action, NULL);
sigaction(SIGINT, &action, NULL);
@ -428,6 +433,10 @@ int main(int argc, char *argv[]) {
char buffer[4096];
while (1) {
if (exit_upon_signal) {
fprintf(stderr, "Exiting due to signal.\n");
exit(1);
}
struct timeval tv;
gettimeofday(&tv, NULL);
if (output_format == O_I3BAR)