| /* vi: set sw=4 ts=4: */ |
| /* |
| * Mini watchdog implementation for busybox |
| * |
| * Copyright (C) 2003 Paul Mundt <lethal@linux-sh.org> |
| * Copyright (C) 2006 Bernhard Reutner-Fischer <busybox@busybox.net> |
| * Copyright (C) 2008 Darius Augulis <augulis.darius@gmail.com> |
| * |
| * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
| */ |
| |
| //usage:#define watchdog_trivial_usage |
| //usage: "[-t N[ms]] [-T N[ms]] [-F] DEV" |
| //usage:#define watchdog_full_usage "\n\n" |
| //usage: "Periodically write to watchdog device DEV\n" |
| //usage: "\n -T N Reboot after N seconds if not reset (default 60)" |
| //usage: "\n -t N Reset every N seconds (default 30)" |
| //usage: "\n -F Run in foreground" |
| //usage: "\n" |
| //usage: "\nUse 500ms to specify period in milliseconds" |
| |
| #include "libbb.h" |
| #include "linux/types.h" /* for __u32 */ |
| #include "linux/watchdog.h" |
| |
| #define OPT_FOREGROUND (1 << 0) |
| #define OPT_STIMER (1 << 1) |
| #define OPT_HTIMER (1 << 2) |
| |
| static void watchdog_shutdown(int sig UNUSED_PARAM) |
| { |
| static const char V = 'V'; |
| |
| remove_pidfile(CONFIG_PID_FILE_PATH "/watchdog.pid"); |
| write(3, &V, 1); /* Magic, see watchdog-api.txt in kernel */ |
| if (ENABLE_FEATURE_CLEAN_UP) |
| close(3); |
| _exit(EXIT_SUCCESS); |
| } |
| |
| int watchdog_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| int watchdog_main(int argc, char **argv) |
| { |
| static const struct suffix_mult suffixes[] = { |
| { "ms", 1 }, |
| { "", 1000 }, |
| { "", 0 } |
| }; |
| |
| unsigned opts; |
| unsigned stimer_duration; /* how often to restart */ |
| unsigned htimer_duration = 60000; /* reboots after N ms if not restarted */ |
| char *st_arg; |
| char *ht_arg; |
| |
| opt_complementary = "=1"; /* must have exactly 1 argument */ |
| opts = getopt32(argv, "Ft:T:", &st_arg, &ht_arg); |
| |
| /* We need to daemonize *before* opening the watchdog as many drivers |
| * will only allow one process at a time to do so. Since daemonizing |
| * is not perfect (child may run before parent finishes exiting), we |
| * can't rely on parent exiting before us (let alone *cleanly* releasing |
| * the watchdog fd -- something else that may not even be allowed). |
| */ |
| if (!(opts & OPT_FOREGROUND)) |
| bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv); |
| |
| if (opts & OPT_HTIMER) |
| htimer_duration = xatou_sfx(ht_arg, suffixes); |
| stimer_duration = htimer_duration / 2; |
| if (opts & OPT_STIMER) |
| stimer_duration = xatou_sfx(st_arg, suffixes); |
| |
| bb_signals(BB_FATAL_SIGS, watchdog_shutdown); |
| |
| /* Use known fd # - avoid needing global 'int fd' */ |
| xmove_fd(xopen(argv[argc - 1], O_WRONLY), 3); |
| |
| /* WDIOC_SETTIMEOUT takes seconds, not milliseconds */ |
| htimer_duration = htimer_duration / 1000; |
| #ifndef WDIOC_SETTIMEOUT |
| # error WDIOC_SETTIMEOUT is not defined, cannot compile watchdog applet |
| #else |
| # if defined WDIOC_SETOPTIONS && defined WDIOS_ENABLECARD |
| { |
| static const int enable = WDIOS_ENABLECARD; |
| ioctl_or_warn(3, WDIOC_SETOPTIONS, (void*) &enable); |
| } |
| # endif |
| ioctl_or_warn(3, WDIOC_SETTIMEOUT, &htimer_duration); |
| #endif |
| |
| #if 0 |
| ioctl_or_warn(3, WDIOC_GETTIMEOUT, &htimer_duration); |
| printf("watchdog: SW timer is %dms, HW timer is %ds\n", |
| stimer_duration, htimer_duration * 1000); |
| #endif |
| |
| write_pidfile(CONFIG_PID_FILE_PATH "/watchdog.pid"); |
| |
| while (1) { |
| /* |
| * Make sure we clear the counter before sleeping, |
| * as the counter value is undefined at this point -- PFM |
| */ |
| write(3, "", 1); /* write zero byte */ |
| usleep(stimer_duration * 1000L); |
| } |
| return EXIT_SUCCESS; /* - not reached, but gcc 4.2.1 is too dumb! */ |
| } |