Handle a signal

Hi, in my little programme i have to handle the signal SIGTERM, and following basic steps this is what i do:

Code:

int main(int argc, char* argv[]) {
	if (argc<2) return -1;
	struct sigaction ac;
	serverChannel_t srv;
	channel_t clnt;
	(void)unlink(SOCKPATH);
	snprintf(dirpath, FILENAME_MAX+1, argv[1]);
	if (!(planners=read_planners(dirpath))) {
			perror("Erorr during planners initialization\n");
			exit(EXIT_FAILURE);
	}
	if ((srv=createServerChannel(SOCKPATH))<=0) {
		perror("Erorr during socket initialization");
		exit(EXIT_FAILURE);
	}
	memset(&ac, 0, sizeof(ac));
	ac.sa_handler=sig_handler;   //handler of the function
	sigaction(SIGTERM, &ac, NULL);
        .............................
        .............................
}
/* the handler */
static void sig_handler(int n) {
	int i=0;printf("Handler is executing!\n"); fflush(stdout);
	plan_t * next;
	while (many_tids>0)printf("<%d>;", many_tids);
	if (planners) {
		write_planners(dirpath, planners));
		while (i++<plan_elems) {
			next=planners->nxt;
			dealloca_lista(planners->events);
			free(planners);
			planners=next;
		}
	}
	(void)unlink(SOCKPATH);
	exit(EXIT_SUCCESS);
}

The handler works fine, i mean when the signal is sent to the process the handlers is executed.
The problem is that i have a script bash which does several tests on this program, and one of these is:

Code:

if  ! killall -w -TERM dserver; then
    echo Error: SIGTERM not handled
    exit 1
fi

The killall command return 0 if the process terminates, otherwise it will return a number different from 0, so that script line means, if killall fails print on the screen that message.
the '-w' option specifies that killall has to wait, cause the process might invoke some cleanup function (is my case), so if the process decides to ignore the SIGTERM, killall -w will never return.
Unfortunately what i get wen i run the script is the message "SIGTERM not handled"!
Any idea please?

Read this - http://linuxreviews.org/man/signal/
Scroll down to "Async-signal-safe functions"
Rewrite your signal handler.

> Unfortunately what i get wen i run the script is the message "SIGTERM not handled"!
You're meant to "get out of Dodge" with all due dispatch, not dawdle around doing all the things you would normally do at a normal program exit.

If you take too long, it (the shell) might give up waiting.

Originally Posted by flexo87

The killall command return 0 if the process terminates, otherwise it will return a number different from 0, so that script line means, if killall fails print on the screen that message.
the '-w' option specifies that killall has to wait, cause the process might invoke some cleanup function (is my case), so if the process decides to ignore the SIGTERM, killall -w will never return.
Unfortunately what i get wen i run the script is the message "SIGTERM not handled"!
Any idea please?

Well your script is logically inconistant, you tell kill to wait 'if it is not working' however then
you say to print an error mesage if it did not work.

Logically that script cannot produce that error message.

So it didn't, you are deluding yourself, it never happened. (stay off the drugs)

What happens if you use a logical script?
Such as:-

Code:

if  ! killall -TERM dserver; then
    echo Error: SIGTERM not handled
    exit 1
fi