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