compilers/linux86-0.16.17/libc/misc/system.c

   1
   2 #include <stddef.h>
   3 #include <signal.h>
   4
   5 int
   6 system(command)
   7 char * command;
   8 {
   9    int wait_val, wait_ret, pid;
  10    __sighandler_t save_quit;
  11    __sighandler_t save_int;
  12
  13    if( command == 0 ) return 1;
  14
  15    save_quit = signal(SIGQUIT, SIG_IGN);
  16    save_int  = signal(SIGINT,  SIG_IGN);
  17
  18    if( (pid=vfork()) < 0 )
  19    {
  20       signal(SIGQUIT, save_quit);
  21       signal(SIGINT,  save_int);
  22       return -1;
  23    }
  24    if( pid == 0 )
  25    {
  26       signal(SIGQUIT, SIG_DFL);
  27       signal(SIGINT,  SIG_DFL);
  28
  29       execl("/bin/sh", "sh", "-c", command, (char*)0);
  30       _exit(127);
  31    }
  32    /* Signals are not absolutly guarenteed with vfork */
  33    signal(SIGQUIT, SIG_IGN);
  34    signal(SIGINT,  SIG_IGN);
  35
  36    do
  37    {
  38       if( (wait_ret = wait(&wait_val)) == -1 )
  39       {
  40          wait_val = -1;
  41          break;
  42       }
  43    }
  44    while( wait_ret != pid );
  45
  46    signal(SIGQUIT, save_quit);
  47    signal(SIGINT,  save_int);
  48    return wait_val;
  49 }