libopkg/xsystem.c

   1 /* xsystem.c - system(3) with error messages
   2
   3    Carl D. Worth
   4
   5    Copyright (C) 2001 University of Southern California
   6
   7    This program is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU General Public License as
   9    published by the Free Software Foundation; either version 2, or (at
  10    your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful, but
  13    WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    General Public License for more details.
  16 */
  17
  18 #include <sys/types.h>
  19 #include <sys/wait.h>
  20 #include <unistd.h>
  21
  22 #include "xsystem.h"
  23 #include "libbb/libbb.h"
  24
  25 /* Like system(3), but with error messages printed if the fork fails
  26    or if the child process dies due to an uncaught signal. Also, the
  27    return value is a bit simpler:
  28
  29    -1 if there was any problem
  30    Otherwise, the 8-bit return value of the program ala WEXITSTATUS
  31    as defined in <sys/wait.h>.
  32 */
  33 int
  34 xsystem(const char *argv[])
  35 {
  36         int status;
  37         pid_t pid;
  38
  39         pid = vfork();
  40
  41         switch (pid) {
  42         case -1:
  43                 opkg_perror(ERROR, "%s: vfork", argv[0]);
  44                 return -1;
  45         case 0:
  46                 /* child */
  47                 execvp(argv[0], (char*const*)argv);
  48                 _exit(-1);
  49         default:
  50                 /* parent */
  51                 break;
  52         }
  53
  54         if (waitpid(pid, &status, 0) == -1) {
  55                 opkg_perror(ERROR, "%s: waitpid", argv[0]);
  56                 return -1;
  57         }
  58
  59         if (WIFSIGNALED(status)) {
  60                 opkg_msg(ERROR, "%s: Child killed by signal %d.\n",
  61                         argv[0], WTERMSIG(status));
  62                 return -1;
  63         }
  64
  65         if (!WIFEXITED(status)) {
  66                 /* shouldn't happen */
  67                 opkg_msg(ERROR, "%s: Your system is broken: got status %d "
  68                         "from waitpid.\n", argv[0], status);
  69                 return -1;
  70         }
  71
  72         return WEXITSTATUS(status);
  73 }