system

int system(const char *command)

#include <sys/types.h>
#include <sys/wait.h>
#include <signal.h>
#include <stdlib.h>
#include <unistd.h>
#include <paths.h>

extern char **environ;

int
system(const char *command)
{
	pid_t pid;
	sig_t intsave, quitsave;
	sigset_t mask, omask;
	int pstat;
	char *argp[] = {"sh", "-c", NULL, NULL};

	if (!command)		/* just checking... */
		return(1);

	argp[2] = (char *)command;

	sigemptyset(&mask);
	sigaddset(&mask, SIGCHLD);
	sigprocmask(SIG_BLOCK, &mask, &omask);
	switch (pid = vfork()) {
	case -1:			/* error */
		sigprocmask(SIG_SETMASK, &omask, NULL);
		return(-1);
	case 0:				/* child */
		sigprocmask(SIG_SETMASK, &omask, NULL);
		execve(_PATH_BSHELL, argp, environ);
		_exit(127);
	}

	intsave = signal(SIGINT, SIG_IGN);
	quitsave = signal(SIGQUIT, SIG_IGN);
	pid = waitpid(pid, (int *)&pstat, 0);
	sigprocmask(SIG_SETMASK, &omask, NULL);
	(void)signal(SIGINT, intsave);
	(void)signal(SIGQUIT, quitsave);
	return (pid == -1 ? -1 : pstat);
}