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#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <signal.h>
#include <sys/wait.h>
#include <sysexits.h>
#include <assert.h>
volatile sig_atomic_t caught_sig = 0;
static void signal_handler(int which)
{
caught_sig = which;
}
static int wait_for_process(pid_t pid)
{
int rv = EX_SOFTWARE;
int status = 0;
int i = 0;
struct sigaction sig_handler;
memset(&sig_handler, 0, sizeof(struct sigaction));
sig_handler.sa_handler = signal_handler;
sig_handler.sa_flags = 0;
sigaction(SIGALRM, &sig_handler, NULL);
sigaction(SIGHUP, &sig_handler, NULL);
sigaction(SIGINT, &sig_handler, NULL);
sigaction(SIGUSR1, &sig_handler, NULL);
sigaction(SIGTERM, &sig_handler, NULL);
sigaction(SIGPIPE, &sig_handler, NULL);
/* Loop forever waiting for the process to quit */
for (i = 0; ;i++) {
pid_t p = waitpid(pid, &status, 0);
if (p == pid) {
/* child exited. Let's get out of here */
rv = WIFEXITED(status) ?
WEXITSTATUS(status) :
(0x80 | WTERMSIG(status));
break;
} else {
int sig = 0;
/* pass along SIGHUP gracefully */
if (caught_sig == SIGHUP) {
i = 0;
int sig = caught_sig;
if (kill(pid, sig) < 0) {
/* Kill failed. Must have lost the process. :/ */
perror("lost child when trying to kill");
}
continue;
}
switch (i) {
case 0:
/* On the first iteration, pass the signal through */
sig = caught_sig > 0 ? caught_sig : SIGTERM;
if (caught_sig == SIGALRM) {
fprintf(stderr, "Timeout.. killing the process\n");
}
break;
case 1:
sig = SIGTERM;
break;
default:
sig = SIGKILL;
break;
}
if (kill(pid, sig) < 0) {
/* Kill failed. Must have lost the process. :/ */
perror("lost child when trying to kill");
}
/* Wait up to 5 seconds for the pid */
alarm(5);
}
}
return rv;
}
static int spawn_and_wait(char **argv)
{
int rv = EX_SOFTWARE;
pid_t pid = fork();
switch (pid) {
case -1:
perror("fork");
rv = EX_OSERR;
break; /* NOTREACHED */
case 0:
execvp(argv[0], argv);
perror("exec");
rv = EX_SOFTWARE;
break; /* NOTREACHED */
default:
rv = wait_for_process(pid);
}
return rv;
}
static void usage(void) {
fprintf(stderr, "./timedrun <naptime in sec> args...\n");
exit(-1);
}
int main(int argc, char **argv)
{
int naptime = 0;
if (argc < 3)
usage();
naptime = atoi(argv[1]);
assert(naptime > 0 && naptime < 1800);
alarm(naptime);
return spawn_and_wait(argv+2);
}
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