/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 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 */ //config:config TIMEOUT //config: bool "timeout (6 kb)" //config: default y //config: help //config: Runs a program and watches it. If it does not terminate in //config: specified number of seconds, it is sent a signal. //applet:IF_TIMEOUT(APPLET(timeout, BB_DIR_USR_BIN, BB_SUID_DROP)) //kbuild:lib-$(CONFIG_TIMEOUT) += timeout.o //usage:#define timeout_trivial_usage //usage: "[-s SIG] [-k KILL_SECS] SECS PROG ARGS" //usage:#define timeout_full_usage "\n\n" //usage: "Run PROG. Send SIG to it if it is not gone in SECS seconds.\n" //usage: "Default SIG: TERM." //usage: "If it still exists in KILL_SECS seconds, send KILL.\n" #include "libbb.h" static NOINLINE int timeout_wait(int timeout, pid_t pid) { /* Just sleep(HUGE_NUM); kill(parent) may kill wrong process! */ while (1) { sleep1(); if (--timeout <= 0) break; if (kill(pid, 0)) { /* process is gone */ return EXIT_SUCCESS; } } return EXIT_FAILURE; } 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; int kill_timeout; pid_t pid; #if !BB_MMU char *sv1, *sv2; #endif const char *opt_s = "TERM"; char *opt_k = NULL; /* -p option is not documented, it is needed to support NOMMU. */ /* -t SECONDS; -p PARENT_PID */ /* '+': stop at first non-option */ getopt32(argv, "+s:k:" USE_FOR_NOMMU("p:+"), &opt_s, &opt_k, &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); kill_timeout = 0; if (opt_k) kill_timeout = parse_duration_str(opt_k); if (!argv[optind]) bb_show_usage(); timeout = parse_duration_str(argv[optind++]); if (!argv[optind]) /* no PROG? */ bb_show_usage(); /* 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 !BB_MMU sv1 = argv[optind]; sv2 = argv[optind + 1]; #endif pid = xvfork(); 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: if (timeout_wait(timeout, parent) == EXIT_SUCCESS) return EXIT_SUCCESS; kill(parent, signo); if (kill_timeout > 0) { if (timeout_wait(kill_timeout, parent) == EXIT_SUCCESS) return EXIT_SUCCESS; kill(parent, SIGKILL); } 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_or_die(argv); }