| 1 | /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
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| 2 | * COPYING NOTES
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| 3 | *
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| 4 | * timeout.c -- a timeout handler for shell commands
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| 5 | *
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| 6 | * Copyright (C) 2005-6, Roberto A. Foglietta <me@roberto.foglietta.name>
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| 7 | *
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| 8 | * This program is free software; you can redistribute it and/or modify
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| 9 | * it under the terms of the GNU General Public License as published by
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| 10 | * the Free Software Foundation; version 2 of the License.
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| 11 | *
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| 12 | * This program is distributed in the hope that it will be useful,
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| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 15 | * GNU General Public License for more details.
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| 16 | *
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| 17 | * You should have received a copy of the GNU General Public License
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| 18 | * along with this program; if not, write to the Free Software
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| 19 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
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| 20 | */
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| 21 | /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
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| 22 | * REVISION NOTES:
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| 23 | * released 17-11-2005 by Roberto A. Foglietta
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| 24 | * talarm 04-12-2005 by Roberto A. Foglietta
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| 25 | * modified 05-12-2005 by Roberto A. Foglietta
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| 26 | * sizerdct 06-12-2005 by Roberto A. Foglietta
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| 27 | * splitszf 12-05-2006 by Roberto A. Foglietta
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| 28 | * rewrite 14-11-2008 vda
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| 29 | */
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| 30 |
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| 31 | //usage:#define timeout_trivial_usage
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| 32 | //usage: "[-t SECS] [-s SIG] PROG ARGS"
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| 33 | //usage:#define timeout_full_usage "\n\n"
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| 34 | //usage: "Runs PROG. Sends SIG to it if it is not gone in SECS seconds.\n"
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| 35 | //usage: "Defaults: SECS: 10, SIG: TERM."
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| 36 |
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| 37 | #include "libbb.h"
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| 38 |
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| 39 | int timeout_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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| 40 | int timeout_main(int argc UNUSED_PARAM, char **argv)
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| 41 | {
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| 42 | int signo;
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| 43 | int status;
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| 44 | int parent = 0;
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| 45 | int timeout = 10;
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| 46 | pid_t pid;
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| 47 | #if !BB_MMU
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| 48 | char *sv1, *sv2;
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| 49 | #endif
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| 50 | const char *opt_s = "TERM";
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| 51 |
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| 52 | /* -p option is not documented, it is needed to support NOMMU. */
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| 53 |
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| 54 | /* -t SECONDS; -p PARENT_PID */
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| 55 | opt_complementary = "t+" USE_FOR_NOMMU(":p+");
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| 56 | /* '+': stop at first non-option */
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| 57 | getopt32(argv, "+s:t:" USE_FOR_NOMMU("p:"), &opt_s, &timeout, &parent);
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| 58 | /*argv += optind; - no, wait for bb_daemonize_or_rexec! */
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| 59 | signo = get_signum(opt_s);
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| 60 | if (signo < 0)
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| 61 | bb_error_msg_and_die("unknown signal '%s'", opt_s);
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| 62 |
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| 63 | /* We want to create a grandchild which will watch
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| 64 | * and kill the grandparent. Other methods:
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| 65 | * making parent watch child disrupts parent<->child link
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| 66 | * (example: "tcpsvd 0.0.0.0 1234 timeout service_prog" -
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| 67 | * it's better if service_prog is a child of tcpsvd!),
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| 68 | * making child watch parent results in programs having
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| 69 | * unexpected children. */
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| 70 |
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| 71 | if (parent) /* we were re-execed, already grandchild */
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| 72 | goto grandchild;
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| 73 | if (!argv[optind]) /* no PROG? */
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| 74 | bb_show_usage();
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| 75 |
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| 76 | #if !BB_MMU
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| 77 | sv1 = argv[optind];
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| 78 | sv2 = argv[optind + 1];
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| 79 | #endif
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| 80 | pid = xvfork();
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| 81 | if (pid == 0) {
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| 82 | /* Child: spawn grandchild and exit */
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| 83 | parent = getppid();
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| 84 | #if !BB_MMU
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| 85 | argv[optind] = xasprintf("-p%u", parent);
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| 86 | argv[optind + 1] = NULL;
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| 87 | #endif
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| 88 | /* NB: exits with nonzero on error: */
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| 89 | bb_daemonize_or_rexec(0, argv);
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| 90 | /* Here we are grandchild. Sleep, then kill grandparent */
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| 91 | grandchild:
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| 92 | /* Just sleep(HUGE_NUM); kill(parent) may kill wrong process! */
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| 93 | while (1) {
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| 94 | sleep(1);
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| 95 | if (--timeout <= 0)
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| 96 | break;
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| 97 | if (kill(parent, 0)) {
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| 98 | /* process is gone */
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| 99 | return EXIT_SUCCESS;
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| 100 | }
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| 101 | }
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| 102 | kill(parent, signo);
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| 103 | return EXIT_SUCCESS;
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| 104 | }
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| 105 |
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| 106 | /* Parent */
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| 107 | wait(&status); /* wait for child to die */
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| 108 | /* Did intermediate [v]fork or exec fail? */
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| 109 | if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
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| 110 | return EXIT_FAILURE;
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| 111 | /* Ok, exec a program as requested */
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| 112 | argv += optind;
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| 113 | #if !BB_MMU
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| 114 | argv[0] = sv1;
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| 115 | argv[1] = sv2;
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| 116 | #endif
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| 117 | BB_EXECVP_or_die(argv);
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| 118 | }
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