busybox/miscutils/watchdog.c

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/* 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.
*/
//config:config WATCHDOG
//config: bool "watchdog (5.3 kb)"
//config: default y
//config: help
//config: The watchdog utility is used with hardware or software watchdog
//config: device drivers. It opens the specified watchdog device special file
//config: and periodically writes a magic character to the device. If the
//config: watchdog applet ever fails to write the magic character within a
//config: certain amount of time, the watchdog device assumes the system has
//config: hung, and will cause the hardware to reboot.
watchdog: make open-write-close-open functionality a config knob The behaviour introduced by commit 31c765081dc4 ("watchdog: stop watchdog first on startup") causes warnings in the kernel log when the nowayout feature is enabled: [ 16.212184] watchdog: watchdog0: nowayout prevents watchdog being stopped! [ 16.212196] watchdog: watchdog0: watchdog did not stop! The latter may also appear by itself in case the watchdog is of the type that cannot be stopped once started (e.g. the common always-running gpio_wdt kind). These warnings can be somewhat ominous and distracting, so allow configuring whether to use this open-write-close-open sequence rather than just open. Also saves a bit of .text when disabled: function old new delta shutdown_on_signal 31 58 +27 watchdog_main 339 306 -33 shutdown_watchdog 34 - -34 ------------------------------------------------------------------------------ (add/remove: 0/1 grow/shrink: 1/1 up/down: 27/-67) Total: -40 bytes Make it default n: - It's a workaround for one specific type of watchdog (and that seems to be a defect in the kernel driver) - Even when not enabled in busybox config, it can easily be implemented outside busybox - Code size - Commit 31c765081dc4 should be considered a regression for all the boards that now end up with KERN_CRIT warnings in dmesg. - The author of that commit said "This use case is evidently rare, so if it is indeed causing problems for other people I'd OK then I understand whatever needs to be done." in the v1 thread. Cc: Matt Spinler <mspinler@linux.vnet.ibm.com> Cc: deweloper@wp.pl Cc: tito <farmatito@tiscali.it> Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2021-04-06 13:44:53 +05:30
//config:
//config:config FEATURE_WATCHDOG_OPEN_TWICE
//config: bool "Open watchdog device twice, closing it gracefully in between"
//config: depends on WATCHDOG
//config: default n # this behavior was essentially a hack for a broken driver
//config: help
//config: When enabled, the watchdog device is opened and then immediately
//config: magic-closed, before being opened a second time. This may be necessary
//config: for some watchdog devices, but can cause spurious warnings in the
//config: kernel log if the nowayout feature is enabled. If this workaround
watchdog: make open-write-close-open functionality a config knob The behaviour introduced by commit 31c765081dc4 ("watchdog: stop watchdog first on startup") causes warnings in the kernel log when the nowayout feature is enabled: [ 16.212184] watchdog: watchdog0: nowayout prevents watchdog being stopped! [ 16.212196] watchdog: watchdog0: watchdog did not stop! The latter may also appear by itself in case the watchdog is of the type that cannot be stopped once started (e.g. the common always-running gpio_wdt kind). These warnings can be somewhat ominous and distracting, so allow configuring whether to use this open-write-close-open sequence rather than just open. Also saves a bit of .text when disabled: function old new delta shutdown_on_signal 31 58 +27 watchdog_main 339 306 -33 shutdown_watchdog 34 - -34 ------------------------------------------------------------------------------ (add/remove: 0/1 grow/shrink: 1/1 up/down: 27/-67) Total: -40 bytes Make it default n: - It's a workaround for one specific type of watchdog (and that seems to be a defect in the kernel driver) - Even when not enabled in busybox config, it can easily be implemented outside busybox - Code size - Commit 31c765081dc4 should be considered a regression for all the boards that now end up with KERN_CRIT warnings in dmesg. - The author of that commit said "This use case is evidently rare, so if it is indeed causing problems for other people I'd OK then I understand whatever needs to be done." in the v1 thread. Cc: Matt Spinler <mspinler@linux.vnet.ibm.com> Cc: deweloper@wp.pl Cc: tito <farmatito@tiscali.it> Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2021-04-06 13:44:53 +05:30
//config: is really needed for you machine to work properly, consider whether
//config: it should be fixed in the kernel driver instead. Even when disabled,
//config: the behaviour is easily emulated with a "printf 'V' > /dev/watchdog"
//config: immediately before starting the busybox watchdog daemon. Say n unless
//config: you know that you absolutely need this.
//applet:IF_WATCHDOG(APPLET(watchdog, BB_DIR_SBIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_WATCHDOG) += watchdog.o
//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>
#ifndef WDIOC_SETOPTIONS
# define WDIOC_SETOPTIONS 0x5704
#endif
#ifndef WDIOC_SETTIMEOUT
# define WDIOC_SETTIMEOUT 0x5706
#endif
#ifndef WDIOC_GETTIMEOUT
# define WDIOC_GETTIMEOUT 0x5707
#endif
#ifndef WDIOS_ENABLECARD
# define WDIOS_ENABLECARD 2
#endif
static void shutdown_watchdog(void)
{
static const char V = 'V';
write(3, &V, 1); /* Magic, see watchdog-api.txt in kernel */
close(3);
}
static void shutdown_on_signal(int sig UNUSED_PARAM)
{
remove_pidfile_std_path_and_ext("watchdog");
shutdown_watchdog();
_exit_SUCCESS();
}
static void watchdog_open(const char* device)
{
/* Use known fd # - avoid needing global 'int fd' */
xmove_fd(xopen(device, O_WRONLY), 3);
watchdog: make open-write-close-open functionality a config knob The behaviour introduced by commit 31c765081dc4 ("watchdog: stop watchdog first on startup") causes warnings in the kernel log when the nowayout feature is enabled: [ 16.212184] watchdog: watchdog0: nowayout prevents watchdog being stopped! [ 16.212196] watchdog: watchdog0: watchdog did not stop! The latter may also appear by itself in case the watchdog is of the type that cannot be stopped once started (e.g. the common always-running gpio_wdt kind). These warnings can be somewhat ominous and distracting, so allow configuring whether to use this open-write-close-open sequence rather than just open. Also saves a bit of .text when disabled: function old new delta shutdown_on_signal 31 58 +27 watchdog_main 339 306 -33 shutdown_watchdog 34 - -34 ------------------------------------------------------------------------------ (add/remove: 0/1 grow/shrink: 1/1 up/down: 27/-67) Total: -40 bytes Make it default n: - It's a workaround for one specific type of watchdog (and that seems to be a defect in the kernel driver) - Even when not enabled in busybox config, it can easily be implemented outside busybox - Code size - Commit 31c765081dc4 should be considered a regression for all the boards that now end up with KERN_CRIT warnings in dmesg. - The author of that commit said "This use case is evidently rare, so if it is indeed causing problems for other people I'd OK then I understand whatever needs to be done." in the v1 thread. Cc: Matt Spinler <mspinler@linux.vnet.ibm.com> Cc: deweloper@wp.pl Cc: tito <farmatito@tiscali.it> Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2021-04-06 13:44:53 +05:30
#if ENABLE_FEATURE_WATCHDOG_OPEN_TWICE
/* If the watchdog driver can do something other than cause a reboot
* on a timeout, then it's possible this program may be starting from
* a state when the watchdog hadn't been previously stopped with
* the magic write followed by a close. In this case the driver may
* not start properly, so always do the proper stop first just in case.
*/
shutdown_watchdog();
xmove_fd(xopen(device, O_WRONLY), 3);
watchdog: make open-write-close-open functionality a config knob The behaviour introduced by commit 31c765081dc4 ("watchdog: stop watchdog first on startup") causes warnings in the kernel log when the nowayout feature is enabled: [ 16.212184] watchdog: watchdog0: nowayout prevents watchdog being stopped! [ 16.212196] watchdog: watchdog0: watchdog did not stop! The latter may also appear by itself in case the watchdog is of the type that cannot be stopped once started (e.g. the common always-running gpio_wdt kind). These warnings can be somewhat ominous and distracting, so allow configuring whether to use this open-write-close-open sequence rather than just open. Also saves a bit of .text when disabled: function old new delta shutdown_on_signal 31 58 +27 watchdog_main 339 306 -33 shutdown_watchdog 34 - -34 ------------------------------------------------------------------------------ (add/remove: 0/1 grow/shrink: 1/1 up/down: 27/-67) Total: -40 bytes Make it default n: - It's a workaround for one specific type of watchdog (and that seems to be a defect in the kernel driver) - Even when not enabled in busybox config, it can easily be implemented outside busybox - Code size - Commit 31c765081dc4 should be considered a regression for all the boards that now end up with KERN_CRIT warnings in dmesg. - The author of that commit said "This use case is evidently rare, so if it is indeed causing problems for other people I'd OK then I understand whatever needs to be done." in the v1 thread. Cc: Matt Spinler <mspinler@linux.vnet.ibm.com> Cc: deweloper@wp.pl Cc: tito <farmatito@tiscali.it> Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2021-04-06 13:44:53 +05:30
#endif
}
int watchdog_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int watchdog_main(int argc UNUSED_PARAM, char **argv)
{
static const int enable = WDIOS_ENABLECARD;
static const struct suffix_mult suffixes[] ALIGN_SUFFIX = {
{ "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;
watchdog: make open-write-close-open functionality a config knob The behaviour introduced by commit 31c765081dc4 ("watchdog: stop watchdog first on startup") causes warnings in the kernel log when the nowayout feature is enabled: [ 16.212184] watchdog: watchdog0: nowayout prevents watchdog being stopped! [ 16.212196] watchdog: watchdog0: watchdog did not stop! The latter may also appear by itself in case the watchdog is of the type that cannot be stopped once started (e.g. the common always-running gpio_wdt kind). These warnings can be somewhat ominous and distracting, so allow configuring whether to use this open-write-close-open sequence rather than just open. Also saves a bit of .text when disabled: function old new delta shutdown_on_signal 31 58 +27 watchdog_main 339 306 -33 shutdown_watchdog 34 - -34 ------------------------------------------------------------------------------ (add/remove: 0/1 grow/shrink: 1/1 up/down: 27/-67) Total: -40 bytes Make it default n: - It's a workaround for one specific type of watchdog (and that seems to be a defect in the kernel driver) - Even when not enabled in busybox config, it can easily be implemented outside busybox - Code size - Commit 31c765081dc4 should be considered a regression for all the boards that now end up with KERN_CRIT warnings in dmesg. - The author of that commit said "This use case is evidently rare, so if it is indeed causing problems for other people I'd OK then I understand whatever needs to be done." in the v1 thread. Cc: Matt Spinler <mspinler@linux.vnet.ibm.com> Cc: deweloper@wp.pl Cc: tito <farmatito@tiscali.it> Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2021-04-06 13:44:53 +05:30
#define OPT_FOREGROUND (1 << 0)
#define OPT_STIMER (1 << 1)
#define OPT_HTIMER (1 << 2)
getopt32: remove opt_complementary function old new delta vgetopt32 1318 1392 +74 runsvdir_main 703 713 +10 bb_make_directory 423 425 +2 collect_cpu 546 545 -1 opt_chars 3 - -3 opt_complementary 4 - -4 tftpd_main 567 562 -5 ntp_init 476 471 -5 zcip_main 1266 1256 -10 xxd_main 428 418 -10 whois_main 140 130 -10 who_main 463 453 -10 which_main 212 202 -10 wget_main 2535 2525 -10 watchdog_main 291 281 -10 watch_main 222 212 -10 vlock_main 399 389 -10 uuencode_main 332 322 -10 uudecode_main 316 306 -10 unlink_main 45 35 -10 udhcpd_main 1482 1472 -10 udhcpc_main 2762 2752 -10 tune2fs_main 290 280 -10 tunctl_main 366 356 -10 truncate_main 218 208 -10 tr_main 518 508 -10 time_main 1134 1124 -10 tftp_main 286 276 -10 telnetd_main 1873 1863 -10 tcpudpsvd_main 1785 1775 -10 taskset_main 521 511 -10 tar_main 1009 999 -10 tail_main 1644 1634 -10 syslogd_main 1967 1957 -10 switch_root_main 368 358 -10 svlogd_main 1454 1444 -10 sv 1296 1286 -10 stat_main 104 94 -10 start_stop_daemon_main 1028 1018 -10 split_main 542 532 -10 sort_main 796 786 -10 slattach_main 624 614 -10 shuf_main 504 494 -10 setsid_main 96 86 -10 setserial_main 1132 1122 -10 setfont_main 388 378 -10 setconsole_main 78 68 -10 sendmail_main 1209 1199 -10 sed_main 677 667 -10 script_main 1077 1067 -10 run_parts_main 325 315 -10 rtcwake_main 454 444 -10 rm_main 175 165 -10 reformime_main 119 109 -10 readlink_main 123 113 -10 rdate_main 246 236 -10 pwdx_main 189 179 -10 pstree_main 317 307 -10 pscan_main 663 653 -10 popmaildir_main 818 808 -10 pmap_main 80 70 -10 nc_main 1042 1032 -10 mv_main 558 548 -10 mountpoint_main 477 467 -10 mount_main 1264 1254 -10 modprobe_main 768 758 -10 modinfo_main 333 323 -10 mktemp_main 200 190 -10 mkswap_main 324 314 -10 mkfs_vfat_main 1489 1479 -10 microcom_main 715 705 -10 md5_sha1_sum_main 521 511 -10 man_main 867 857 -10 makedevs_main 1052 1042 -10 ls_main 563 553 -10 losetup_main 432 422 -10 loadfont_main 89 79 -10 ln_main 524 514 -10 link_main 75 65 -10 ipcalc_main 544 534 -10 iostat_main 2397 2387 -10 install_main 768 758 -10 id_main 480 470 -10 i2cset_main 1239 1229 -10 i2cget_main 380 370 -10 i2cdump_main 1482 1472 -10 i2cdetect_main 682 672 -10 hwclock_main 406 396 -10 httpd_main 741 731 -10 grep_main 837 827 -10 getty_main 1559 1549 -10 fuser_main 297 287 -10 ftpgetput_main 345 335 -10 ftpd_main 2232 2222 -10 fstrim_main 251 241 -10 fsfreeze_main 77 67 -10 fsck_minix_main 2921 2911 -10 flock_main 314 304 -10 flashcp_main 740 730 -10 flash_eraseall_main 833 823 -10 fdformat_main 532 522 -10 expand_main 680 670 -10 eject_main 335 325 -10 dumpleases_main 630 620 -10 du_main 314 304 -10 dos2unix_main 441 431 -10 diff_main 1350 1340 -10 df_main 1064 1054 -10 date_main 1095 1085 -10 cut_main 961 951 -10 cryptpw_main 228 218 -10 crontab_main 575 565 -10 crond_main 1149 1139 -10 cp_main 370 360 -10 common_traceroute_main 3834 3824 -10 common_ping_main 1767 1757 -10 comm_main 239 229 -10 cmp_main 655 645 -10 chrt_main 379 369 -10 chpst_main 704 694 -10 chpasswd_main 308 298 -10 chown_main 171 161 -10 chmod_main 158 148 -10 cat_main 428 418 -10 bzip2_main 120 110 -10 blkdiscard_main 264 254 -10 base64_main 221 211 -10 arping_main 1665 1655 -10 ar_main 556 546 -10 adjtimex_main 406 396 -10 adduser_main 882 872 -10 addgroup_main 411 401 -10 acpid_main 1198 1188 -10 optstring 11 - -11 opt_string 18 - -18 OPT_STR 25 - -25 ubi_tools_main 1288 1258 -30 ls_options 31 - -31 ------------------------------------------------------------------------------ (add/remove: 0/6 grow/shrink: 3/129 up/down: 86/-1383) Total: -1297 bytes text data bss dec hex filename 915428 485 6876 922789 e14a5 busybox_old 914629 485 6872 921986 e1182 busybox_unstripped Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-08-09 01:25:02 +05:30
opts = getopt32(argv, "^" "Ft:T:" "\0" "=1"/*must have exactly 1 arg*/,
&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);
/* maybe bb_logenv_override(); here for LOGGING=syslog to work? */
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, shutdown_on_signal);
watchdog_open(argv[optind]);
/* WDIOC_SETTIMEOUT takes seconds, not milliseconds */
htimer_duration = htimer_duration / 1000;
ioctl_or_warn(3, WDIOC_SETOPTIONS, (void*) &enable);
ioctl_or_warn(3, WDIOC_SETTIMEOUT, &htimer_duration);
#if 0
ioctl_or_warn(3, WDIOC_GETTIMEOUT, &htimer_duration);
printf("watchdog: SW timer is %dms, HW timer is %ds\n",
watchdog: make open-write-close-open functionality a config knob The behaviour introduced by commit 31c765081dc4 ("watchdog: stop watchdog first on startup") causes warnings in the kernel log when the nowayout feature is enabled: [ 16.212184] watchdog: watchdog0: nowayout prevents watchdog being stopped! [ 16.212196] watchdog: watchdog0: watchdog did not stop! The latter may also appear by itself in case the watchdog is of the type that cannot be stopped once started (e.g. the common always-running gpio_wdt kind). These warnings can be somewhat ominous and distracting, so allow configuring whether to use this open-write-close-open sequence rather than just open. Also saves a bit of .text when disabled: function old new delta shutdown_on_signal 31 58 +27 watchdog_main 339 306 -33 shutdown_watchdog 34 - -34 ------------------------------------------------------------------------------ (add/remove: 0/1 grow/shrink: 1/1 up/down: 27/-67) Total: -40 bytes Make it default n: - It's a workaround for one specific type of watchdog (and that seems to be a defect in the kernel driver) - Even when not enabled in busybox config, it can easily be implemented outside busybox - Code size - Commit 31c765081dc4 should be considered a regression for all the boards that now end up with KERN_CRIT warnings in dmesg. - The author of that commit said "This use case is evidently rare, so if it is indeed causing problems for other people I'd OK then I understand whatever needs to be done." in the v1 thread. Cc: Matt Spinler <mspinler@linux.vnet.ibm.com> Cc: deweloper@wp.pl Cc: tito <farmatito@tiscali.it> Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2021-04-06 13:44:53 +05:30
stimer_duration, htimer_duration);
#endif
write_pidfile_std_path_and_ext("watchdog");
while (1) {
/*
2008-12-14 20:19:06 +05:30
* Make sure we clear the counter before sleeping,
* as the counter value is undefined at this point -- PFM
*/
write(3, "", 1); /* write zero byte */
msleep(stimer_duration);
}
return EXIT_SUCCESS; /* - not reached, but gcc 4.2.1 is too dumb! */
}