if (child <= -1)
if (child <= -1 && errno != EINTR)
__libc_system (const char *line){  int status, save;  pid_t pid;  struct sigaction sa, intr, quit;#ifndef WAITPID_CANNOT_BLOCK_SIGCHLD  sigset_t block, omask;#endif  if (line == NULL)    /* This signals that we have a command processor available.  */    return 1;  sa.sa_handler = SIG_IGN;  sa.sa_flags = 0;  __sigemptyset (&sa.sa_mask);  if (__sigaction (SIGINT, &sa, &intr) < 0)    return -1;  if (__sigaction (SIGQUIT, &sa, &quit) < 0)    {      save = errno;      (void) __sigaction (SIGINT, &intr, (struct sigaction *) NULL);      __set_errno (save);      return -1;    }#ifndef WAITPID_CANNOT_BLOCK_SIGCHLD/* SCO 3.2v4 has a bug where `waitpid' will never return if SIGCHLD is   blocked.  This makes it impossible for `system' to be implemented in   compliance with POSIX.2-1992.  They have acknowledged that this is a bug   but I have not seen nor heard of any forthcoming fix.  */  __sigemptyset (&block);  __sigaddset (&block, SIGCHLD);  save = errno;  if (__sigprocmask (SIG_BLOCK, &block, &omask) < 0)    {      if (errno == ENOSYS)	__set_errno (save);      else	{	  save = errno;	  (void) __sigaction (SIGINT, &intr, (struct sigaction *) NULL);	  (void) __sigaction (SIGQUIT, &quit, (struct sigaction *) NULL);	  __set_errno (save);	  return -1;	}    }#define UNBLOCK	__sigprocmask (SIG_SETMASK, &omask, (sigset_t *) NULL)#else#define UNBLOCK 0#endif  pid = __vfork ();  if (pid == (pid_t) 0)    {      /* Child side.  */      const char *new_argv[4];      new_argv[0] = SHELL_NAME;      new_argv[1] = "-c";      new_argv[2] = line;      new_argv[3] = NULL;      /* Restore the signals.  */      (void) __sigaction (SIGINT, &intr, (struct sigaction *) NULL);      (void) __sigaction (SIGQUIT, &quit, (struct sigaction *) NULL);      (void) UNBLOCK;      /* Exec the shell.  */      (void) __execve (SHELL_PATH, (char *const *) new_argv, __environ);      _exit (127);    }  else if (pid < (pid_t) 0)    /* The fork failed.  */    status = -1;  else    /* Parent side.  */#ifdef	NO_WAITPID    {      pid_t child;      do	{	  child = __wait (&status);	  if (child <= -1)	    {	      status = -1;	      break;	    }	} while (child != pid);    }#else    if (__waitpid (pid, &status, 0) != pid)      status = -1;#endif  save = errno;  if ((__sigaction (SIGINT, &intr, (struct sigaction *) NULL) |       __sigaction (SIGQUIT, &quit, (struct sigaction *) NULL) |       UNBLOCK) != 0)    {      if (errno == ENOSYS)	__set_errno (save);      else	return -1;    }  return status;}