/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * COPYING NOTES * * timeout.c -- a timeout handler for shell commands * * Copyright (C) 2005-6, Roberto A. Foglietta * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; version 2 of the License. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA. */ /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * REVISION NOTES: * released 17-11-2005 by Roberto A. Foglietta * talarm 04-12-2005 by Roberto A. Foglietta * modified 05-12-2005 by Roberto A. Foglietta * sizerdct 06-12-2005 by Roberto A. Foglietta * splitszf 12-05-2006 by Roberto A. Foglietta * rewrite 14-11-2008 vda */ #include "libbb.h" int timeout_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int timeout_main(int argc UNUSED_PARAM, char **argv) { int signo; int status; int parent = 0; int timeout = 10; pid_t pid; #if !BB_MMU char *sv1, *sv2; #endif const char *opt_s = "TERM"; /* -p option is not documented, it is needed to support NOMMU. */ /* -t SECONDS; -p PARENT_PID */ opt_complementary = "t+" USE_FOR_NOMMU(":p+"); /* '+': stop at first non-option */ getopt32(argv, "+s:t:" USE_FOR_NOMMU("p:"), &opt_s, &timeout, &parent); /*argv += optind; - no, wait for bb_daemonize_or_rexec! */ signo = get_signum(opt_s); if (signo < 0) bb_error_msg_and_die("unknown signal '%s'", opt_s); /* We want to create a grandchild which will watch * and kill the grandparent. Other methods: * making parent watch child disrupts parent<->child link * (example: "tcpsvd 0.0.0.0 1234 timeout service_prog" - * it's better if service_prog is a child of tcpsvd!), * making child watch parent results in programs having * unexpected children. */ if (parent) /* we were re-execed, already grandchild */ goto grandchild; if (!argv[optind]) /* no PROG? */ bb_show_usage(); #if !BB_MMU sv1 = argv[optind]; sv2 = argv[optind + 1]; #endif pid = vfork(); if (pid < 0) bb_perror_msg_and_die("vfork"); if (pid == 0) { /* Child: spawn grandchild and exit */ parent = getppid(); #if !BB_MMU argv[optind] = xasprintf("-p%u", parent); argv[optind + 1] = NULL; #endif /* NB: exits with nonzero on error: */ bb_daemonize_or_rexec(0, argv); /* Here we are grandchild. Sleep, then kill grandparent */ grandchild: /* Just sleep(NUGE_NUM); kill(parent) may kill wrong process! */ while (1) { sleep(1); if (--timeout <= 0) break; if (kill(parent, 0)) { /* process is gone */ return EXIT_SUCCESS; } } kill(parent, signo); return EXIT_SUCCESS; } /* Parent */ wait(&status); /* wait for child to die */ /* Did intermediate [v]fork or exec fail? */ if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) return EXIT_FAILURE; /* Ok, exec a program as requested */ argv += optind; #if !BB_MMU argv[0] = sv1; argv[1] = sv2; #endif BB_EXECVP(argv[0], argv); bb_perror_msg_and_die("can't execute '%s'", argv[0]); }