kill.c

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <signal.h>

static struct {
	unsigned int number;
	char *name;
} signals[] = {
#define _SIG(name) {SIG##name, #name}
	/* Single Unix Specification signals */
	_SIG(ABRT),
	_SIG(ALRM),
	_SIG(FPE),
	_SIG(HUP),
	_SIG(ILL),
	_SIG(INT),
	_SIG(KILL),
	_SIG(PIPE),
	_SIG(QUIT),
	_SIG(SEGV),
	_SIG(TERM),
	_SIG(USR1),
	_SIG(USR2),
	_SIG(CHLD),
	_SIG(CONT),
	_SIG(STOP),
	_SIG(TSTP),
	_SIG(TTIN),
	_SIG(TTOU),
	_SIG(BUS),
#ifdef SIGPOLL
	_SIG(POLL),
#endif
	_SIG(PROF),
	_SIG(SYS),
	_SIG(TRAP),
	_SIG(URG),
	_SIG(VTALRM),
	_SIG(XCPU),
	_SIG(XFSZ),
	/* non-SUS signals */
	_SIG(IO),
#ifdef SIGPWR
	_SIG(PWR),
#endif
#ifdef SIGSTKFLT
	_SIG(STKFLT),
#endif
	_SIG(WINCH),

#ifdef SIGEMT
	_SIG(EMT),
#endif
#ifdef SIGINFO
	_SIG(INFO),
#endif

#undef _SIG
};

/* To indicate a matching signal was not found */
static const unsigned int SENTINEL = (unsigned int) -1;

void list_signals()
{
	unsigned int sorted_signals[NSIG];
	unsigned int i;
	unsigned int num;

	memset(sorted_signals, SENTINEL, sizeof(sorted_signals));

	// Sort the signals
	for(i = 0; i < sizeof(signals)/sizeof(signals[0]); i++) {
		sorted_signals[signals[i].number] = i;
	}

	num = 0;
	for(i = 1; i < NSIG; i++) {
		unsigned int index = sorted_signals[i];
		if(index == SENTINEL) {
			continue;
		}

		fprintf(stderr, "%2d) SIG%-9s ", i, signals[index].name);

		if((num++ % 4) == 3) {
			fprintf(stderr, "\n");
		}
	}

	if(num % 4) {
		fprintf(stderr, "\n");
	}
}

unsigned int name_to_signal(const char *name)
{
	unsigned int i;

	for (i = 1; i < sizeof(signals) / sizeof(signals[0]); i++) {
		if(strcasecmp(name, signals[i].name) == 0) {
			return signals[i].number;
		}
	}

	return SENTINEL;
}

int main(int argc, char **argv)
{
	unsigned int sig = SIGTERM;
	int result = 0;

	argc--;
	argv++;

	if (argc >= 1 && argv[0][0] == '-') {
		//char *endptr;
		size_t arg_len = strlen(argv[0]);
		if (arg_len < 2) {
			fprintf(stderr, "invalid argument: -\n");
			return -1;
		}

		char *arg = *argv + 1;
		if(arg_len == 2) {
			switch(*arg) {
				case 'l':
					list_signals();
					return 0;
				case 'h':
					goto usage;
				case 's':
					sig = name_to_signal(argv[2]);
					if(sig == SENTINEL) {
						sig = atoi(argv[2]);
						if(!sig) {
							fprintf(stderr, "Invalid signal '%s'\n", argv[2]);
							return 1;
						}
					}
			}
		}
		/*
		   sig = strtol(arg, &endptr, 10);
		   if (*endptr != '\0') {
		   sig = name_to_signal(arg);
		   if (sig == SENTINEL) {
		   fprintf(stderr, "invalid signal name: %s\n", arg);
		   return -1;
		   }
		   }
		 */

		argc--;
		argv++;
	}

	if(!argc) {
usage:
		fprintf(stderr, "Usage: kill { [-s <signal>] <pid> | -l }\n");
		return -1;
	}

	while(argc > 0) {
		int pid = atoi(argv[0]);
		int err = kill(pid, sig);
		if(err < 0) {
			result = err;
			fprintf(stderr, "could not kill pid %d: %s\n", pid, strerror(errno));
		}

		argc--;
		argv++;
	}

	return result;
}