[821] | 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * Mini watchdog implementation for busybox
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| 4 | *
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| 5 | * Copyright (C) 2003 Paul Mundt <lethal@linux-sh.org>
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[2725] | 6 | * Copyright (C) 2006 Bernhard Reutner-Fischer <busybox@busybox.net>
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| 7 | * Copyright (C) 2008 Darius Augulis <augulis.darius@gmail.com>
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[821] | 8 | *
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[2725] | 9 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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[821] | 10 | */
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| 11 |
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[3232] | 12 | //usage:#define watchdog_trivial_usage
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| 13 | //usage: "[-t N[ms]] [-T N[ms]] [-F] DEV"
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| 14 | //usage:#define watchdog_full_usage "\n\n"
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| 15 | //usage: "Periodically write to watchdog device DEV\n"
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| 16 | //usage: "\n -T N Reboot after N seconds if not reset (default 60)"
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| 17 | //usage: "\n -t N Reset every N seconds (default 30)"
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| 18 | //usage: "\n -F Run in foreground"
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| 19 | //usage: "\n"
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| 20 | //usage: "\nUse 500ms to specify period in milliseconds"
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| 21 |
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[1765] | 22 | #include "libbb.h"
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[2725] | 23 | #include "linux/types.h" /* for __u32 */
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| 24 | #include "linux/watchdog.h"
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[821] | 25 |
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[2725] | 26 | #define OPT_FOREGROUND (1 << 0)
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| 27 | #define OPT_STIMER (1 << 1)
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| 28 | #define OPT_HTIMER (1 << 2)
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[821] | 29 |
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[2725] | 30 | static void watchdog_shutdown(int sig UNUSED_PARAM)
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[821] | 31 | {
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[2725] | 32 | static const char V = 'V';
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| 33 |
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[3232] | 34 | remove_pidfile(CONFIG_PID_FILE_PATH "/watchdog.pid");
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[2725] | 35 | write(3, &V, 1); /* Magic, see watchdog-api.txt in kernel */
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[1765] | 36 | if (ENABLE_FEATURE_CLEAN_UP)
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| 37 | close(3);
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[2725] | 38 | _exit(EXIT_SUCCESS);
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[821] | 39 | }
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| 40 |
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[2725] | 41 | int watchdog_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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[821] | 42 | int watchdog_main(int argc, char **argv)
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| 43 | {
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[2725] | 44 | static const struct suffix_mult suffixes[] = {
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| 45 | { "ms", 1 },
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| 46 | { "", 1000 },
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| 47 | { "", 0 }
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| 48 | };
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| 49 |
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[1765] | 50 | unsigned opts;
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[2725] | 51 | unsigned stimer_duration; /* how often to restart */
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| 52 | unsigned htimer_duration = 60000; /* reboots after N ms if not restarted */
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| 53 | char *st_arg;
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| 54 | char *ht_arg;
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[821] | 55 |
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[2725] | 56 | opt_complementary = "=1"; /* must have exactly 1 argument */
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| 57 | opts = getopt32(argv, "Ft:T:", &st_arg, &ht_arg);
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[821] | 58 |
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[2725] | 59 | /* We need to daemonize *before* opening the watchdog as many drivers
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| 60 | * will only allow one process at a time to do so. Since daemonizing
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| 61 | * is not perfect (child may run before parent finishes exiting), we
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| 62 | * can't rely on parent exiting before us (let alone *cleanly* releasing
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| 63 | * the watchdog fd -- something else that may not even be allowed).
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| 64 | */
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| 65 | if (!(opts & OPT_FOREGROUND))
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[1765] | 66 | bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
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[821] | 67 |
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[2725] | 68 | if (opts & OPT_HTIMER)
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| 69 | htimer_duration = xatou_sfx(ht_arg, suffixes);
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| 70 | stimer_duration = htimer_duration / 2;
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| 71 | if (opts & OPT_STIMER)
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| 72 | stimer_duration = xatou_sfx(st_arg, suffixes);
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[821] | 73 |
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[2725] | 74 | bb_signals(BB_FATAL_SIGS, watchdog_shutdown);
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| 75 |
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[1765] | 76 | /* Use known fd # - avoid needing global 'int fd' */
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| 77 | xmove_fd(xopen(argv[argc - 1], O_WRONLY), 3);
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[821] | 78 |
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[2725] | 79 | /* WDIOC_SETTIMEOUT takes seconds, not milliseconds */
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| 80 | htimer_duration = htimer_duration / 1000;
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| 81 | #ifndef WDIOC_SETTIMEOUT
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| 82 | # error WDIOC_SETTIMEOUT is not defined, cannot compile watchdog applet
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| 83 | #else
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| 84 | # if defined WDIOC_SETOPTIONS && defined WDIOS_ENABLECARD
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| 85 | {
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| 86 | static const int enable = WDIOS_ENABLECARD;
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| 87 | ioctl_or_warn(3, WDIOC_SETOPTIONS, (void*) &enable);
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| 88 | }
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| 89 | # endif
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| 90 | ioctl_or_warn(3, WDIOC_SETTIMEOUT, &htimer_duration);
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| 91 | #endif
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| 92 |
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| 93 | #if 0
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| 94 | ioctl_or_warn(3, WDIOC_GETTIMEOUT, &htimer_duration);
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| 95 | printf("watchdog: SW timer is %dms, HW timer is %ds\n",
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| 96 | stimer_duration, htimer_duration * 1000);
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| 97 | #endif
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| 98 |
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[3232] | 99 | write_pidfile(CONFIG_PID_FILE_PATH "/watchdog.pid");
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| 100 |
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[821] | 101 | while (1) {
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| 102 | /*
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[2725] | 103 | * Make sure we clear the counter before sleeping,
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| 104 | * as the counter value is undefined at this point -- PFM
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[821] | 105 | */
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[2725] | 106 | write(3, "", 1); /* write zero byte */
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| 107 | usleep(stimer_duration * 1000L);
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[821] | 108 | }
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[2725] | 109 | return EXIT_SUCCESS; /* - not reached, but gcc 4.2.1 is too dumb! */
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[821] | 110 | }
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