system.c raw

   1  #include <unistd.h>
   2  #include <stdlib.h>
   3  #include <signal.h>
   4  #include <sys/wait.h>
   5  #include <spawn.h>
   6  #include <errno.h>
   7  #include "pthread_impl.h"
   8  
   9  extern char **__environ;
  10  
  11  int system(const char *cmd)
  12  {
  13  	pid_t pid;
  14  	sigset_t old, reset;
  15  	struct sigaction sa = { .sa_handler = SIG_IGN }, oldint, oldquit;
  16  	int status = -1, ret;
  17  	posix_spawnattr_t attr;
  18  
  19  	pthread_testcancel();
  20  
  21  	if (!cmd) return 1;
  22  
  23  	sigaction(SIGINT, &sa, &oldint);
  24  	sigaction(SIGQUIT, &sa, &oldquit);
  25  	sigaddset(&sa.sa_mask, SIGCHLD);
  26  	sigprocmask(SIG_BLOCK, &sa.sa_mask, &old);
  27  
  28  	sigemptyset(&reset);
  29  	if (oldint.sa_handler != SIG_IGN) sigaddset(&reset, SIGINT);
  30  	if (oldquit.sa_handler != SIG_IGN) sigaddset(&reset, SIGQUIT);
  31  	posix_spawnattr_init(&attr);
  32  	posix_spawnattr_setsigmask(&attr, &old);
  33  	posix_spawnattr_setsigdefault(&attr, &reset);
  34  	posix_spawnattr_setflags(&attr, POSIX_SPAWN_SETSIGDEF|POSIX_SPAWN_SETSIGMASK);
  35  	ret = posix_spawn(&pid, "/bin/sh", 0, &attr,
  36  		(char *[]){"sh", "-c", (char *)cmd, 0}, __environ);
  37  	posix_spawnattr_destroy(&attr);
  38  
  39  	if (!ret) while (waitpid(pid, &status, 0)<0 && errno == EINTR);
  40  	sigaction(SIGINT, &oldint, NULL);
  41  	sigaction(SIGQUIT, &oldquit, NULL);
  42  	sigprocmask(SIG_SETMASK, &old, NULL);
  43  
  44  	if (ret) errno = ret;
  45  	return status;
  46  }
  47