release/src/router/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 //usage:#define timeout_trivial_usage
  32 //usage:       "[-t SECS] [-s SIG] PROG ARGS"
  33 //usage:#define timeout_full_usage "\n\n"
  34 //usage:       "Runs PROG. Sends SIG to it if it is not gone in SECS seconds.\n"
  35 //usage:       "Defaults: SECS: 10, SIG: TERM."
  36
  37 #include "libbb.h"
  38
  39 int timeout_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  40 int timeout_main(int argc UNUSED_PARAM, char **argv)
  41 {
  42         int signo;
  43         int status;
  44         int parent = 0;
  45         int timeout = 10;
  46         pid_t pid;
  47 #if !BB_MMU
  48         char *sv1, *sv2;
  49 #endif
  50         const char *opt_s = "TERM";
  51
  52         /* -p option is not documented, it is needed to support NOMMU. */
  53
  54         /* -t SECONDS; -p PARENT_PID */
  55         opt_complementary = "t+" USE_FOR_NOMMU(":p+");
  56         /* '+': stop at first non-option */
  57         getopt32(argv, "+s:t:" USE_FOR_NOMMU("p:"), &opt_s, &timeout, &parent);
  58         /*argv += optind; - no, wait for bb_daemonize_or_rexec! */
  59         signo = get_signum(opt_s);
  60         if (signo < 0)
  61                 bb_error_msg_and_die("unknown signal '%s'", opt_s);
  62
  63         /* We want to create a grandchild which will watch
  64          * and kill the grandparent. Other methods:
  65          * making parent watch child disrupts parent<->child link
  66          * (example: "tcpsvd 0.0.0.0 1234 timeout service_prog" -
  67          * it's better if service_prog is a child of tcpsvd!),
  68          * making child watch parent results in programs having
  69          * unexpected children. */
  70
  71         if (parent) /* we were re-execed, already grandchild */
  72                 goto grandchild;
  73         if (!argv[optind]) /* no PROG? */
  74                 bb_show_usage();
  75
  76 #if !BB_MMU
  77         sv1 = argv[optind];
  78         sv2 = argv[optind + 1];
  79 #endif
  80         pid = xvfork();
  81         if (pid == 0) {
  82                 /* Child: spawn grandchild and exit */
  83                 parent = getppid();
  84 #if !BB_MMU
  85                 argv[optind] = xasprintf("-p%u", parent);
  86                 argv[optind + 1] = NULL;
  87 #endif
  88                 /* NB: exits with nonzero on error: */
  89                 bb_daemonize_or_rexec(0, argv);
  90                 /* Here we are grandchild. Sleep, then kill grandparent */
  91  grandchild:
  92                 /* Just sleep(HUGE_NUM); kill(parent) may kill wrong process! */
  93                 while (1) {
  94                         sleep(1);
  95                         if (--timeout <= 0)
  96                                 break;
  97                         if (kill(parent, 0)) {
  98                                 /* process is gone */
  99                                 return EXIT_SUCCESS;
 100                         }
 101                 }
 102                 kill(parent, signo);
 103                 return EXIT_SUCCESS;
 104         }
 105
 106         /* Parent */
 107         wait(&status); /* wait for child to die */
 108         /* Did intermediate [v]fork or exec fail? */
 109         if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
 110                 return EXIT_FAILURE;
 111         /* Ok, exec a program as requested */
 112         argv += optind;
 113 #if !BB_MMU
 114         argv[0] = sv1;
 115         argv[1] = sv2;
 116 #endif
 117         BB_EXECVP_or_die(argv);
 118 }