LXR busybox/miscutils/timeout.c

   1/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
   2 * COPYING NOTES
   3 *
   4 * timeout.c -- a timeout handler for shell commands
   5 *
   6 * Copyright (C) 2005-6, Roberto A. Foglietta <me@roberto.foglietta.name>
   7 *
   8 *   This program is free software; you can redistribute it and/or modify
   9 *   it under the terms of the GNU General Public License as published by
  10 *   the Free Software Foundation; version 2 of the License.
  11 *
  12 *   This program is distributed in the hope that it will be useful,
  13 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 *   GNU General Public License for more details.
  16 *
  17 *   You should have received a copy of the GNU General Public License
  18 *   along with this program; if not, write to the Free Software
  19 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
  20 */
  21/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
  22 * REVISION NOTES:
  23 * released 17-11-2005 by Roberto A. Foglietta
  24 * talarm   04-12-2005 by Roberto A. Foglietta
  25 * modified 05-12-2005 by Roberto A. Foglietta
  26 * sizerdct 06-12-2005 by Roberto A. Foglietta
  27 * splitszf 12-05-2006 by Roberto A. Foglietta
  28 * rewrite  14-11-2008 vda
  29 */
  30
  31#include "libbb.h"
  32
  33int timeout_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  34int timeout_main(int argc UNUSED_PARAM, char **argv)
  35{
  36        int signo;
  37        int status;
  38        int parent = 0;
  39        int timeout = 10;
  40        pid_t pid;
  41#if !BB_MMU
  42        char *sv1, *sv2;
  43#endif
  44        const char *opt_s = "TERM";
  45
  46        /* -p option is not documented, it is needed to support NOMMU. */
  47
  48        /* -t SECONDS; -p PARENT_PID */
  49        opt_complementary = "t+" USE_FOR_NOMMU(":p+");
  50        /* '+': stop at first non-option */
  51        getopt32(argv, "+s:t:" USE_FOR_NOMMU("p:"), &opt_s, &timeout, &parent);
  52        /*argv += optind; - no, wait for bb_daemonize_or_rexec! */
  53        signo = get_signum(opt_s);
  54        if (signo < 0)
  55                bb_error_msg_and_die("unknown signal '%s'", opt_s);
  56
  57        /* We want to create a grandchild which will watch
  58         * and kill the grandparent. Other methods:
  59         * making parent watch child disrupts parent<->child link
  60         * (example: "tcpsvd 0.0.0.0 1234 timeout service_prog" -
  61         * it's better if service_prog is a child of tcpsvd!),
  62         * making child watch parent results in programs having
  63         * unexpected children. */
  64
  65        if (parent) /* we were re-execed, already grandchild */
  66                goto grandchild;
  67        if (!argv[optind]) /* no PROG? */
  68                bb_show_usage();
  69
  70#if !BB_MMU
  71        sv1 = argv[optind];
  72        sv2 = argv[optind + 1];
  73#endif
  74        pid = xvfork();
  75        if (pid == 0) {
  76                /* Child: spawn grandchild and exit */
  77                parent = getppid();
  78#if !BB_MMU
  79                argv[optind] = xasprintf("-p%u", parent);
  80                argv[optind + 1] = NULL;
  81#endif
  82                /* NB: exits with nonzero on error: */
  83                bb_daemonize_or_rexec(0, argv);
  84                /* Here we are grandchild. Sleep, then kill grandparent */
  85 grandchild:
  86                /* Just sleep(NUGE_NUM); kill(parent) may kill wrong process! */
  87                while (1) {
  88                        sleep(1);
  89                        if (--timeout <= 0)
  90                                break;
  91                        if (kill(parent, 0)) {
  92                                /* process is gone */
  93                                return EXIT_SUCCESS;
  94                        }
  95                }
  96                kill(parent, signo);
  97                return EXIT_SUCCESS;
  98        }
  99
 100        /* Parent */
 101        wait(&status); /* wait for child to die */
 102        /* Did intermediate [v]fork or exec fail? */
 103        if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
 104                return EXIT_FAILURE;
 105        /* Ok, exec a program as requested */
 106        argv += optind;
 107#if !BB_MMU
 108        argv[0] = sv1;
 109        argv[1] = sv2;
 110#endif
 111        BB_EXECVP_or_die(argv);
 112}
 113