diff options
| -rw-r--r-- | toys/pending/watchdog.c | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/toys/pending/watchdog.c b/toys/pending/watchdog.c new file mode 100644 index 00000000..0813fe69 --- /dev/null +++ b/toys/pending/watchdog.c @@ -0,0 +1,128 @@ +/* watchdog - start a watchdog timer with configurable kick frequencies + + Author: Chris Sarra, chrissarra@google.com + Date: 25 July 2019 + Ref: kernel.org/doc/Documentation/watchdog/watchdog-api.txt + +USE_WATCHDOG(NEWTOY(watchdog, "Ft#T#", TOYFLAG_NEEDROOT|TOYFLAG_BIN)) + +config WATCHDOG + bool "watchdog" + default y + help + usage: watchdog [-F] [-t SW_TIMER_S] [-T HW_TIMER_S] DEV + + Start the watchdog timer at DEV with optional timeout parameters. + -F run in the foreground (do not daemonize) + -t software timer (in seconds) + -T hardware timer (in seconds) +*/ +#define FOR_watchdog +#include "toys.h" +#include "linux/watchdog.h" + +// Make sure no DEBUG variable is set; change this if you need debug prints! +#undef WATCHDOG_DEBUG + +// Default timeout values in seconds. +#define WATCHDOG_SW_TIMER_S_DEFAULT (4) +#define WATCHDOG_HW_TIMER_S_DEFAULT (60) + +GLOBALS( + long hw_timer_s; + long sw_timer_s; + int fd; +) + +static int intercept_signals(void (*fn)(int)) { + int rc = 0; + struct sigaction sigact; + memset(&sigact, 0, sizeof(sigact)); + sigact.sa_handler = fn; + + rc = sigaction(SIGTERM, &sigact, NULL); +#if defined(WATCHDOG_DEBUG) + if ( rc ) { + printf("failed to create new sigaction for SIGTERM: %d\n", rc); + } +#endif + return rc; +} + +void safe_shutdown(int __attribute__((unused))ignored) { + write(TT.fd, "V", 1); + close(TT.fd); + TT.fd = -1; + error_exit("safely exited watchdog."); +} + +void watchdog_main(void) { + int rc = 0; + long hw_timer_sec = 0; + char *watchdog_dev = NULL; + + if ( toys.optc > 0 ) { + watchdog_dev = toys.optargs[0]; +#if defined(WATCHDOG_DEBUG) + printf("using dev @ '%s'\n", watchdog_dev); +#endif + } else { + error_exit("watchdog dev required"); + } + + // Set default values for timeouts if no flags + if (!(toys.optflags & FLAG_t)) { + TT.sw_timer_s = WATCHDOG_SW_TIMER_S_DEFAULT; +#if defined(WATCHDOG_DEBUG) + printf("using default sw_timer_s.\n"); +#endif + } + + if (!(toys.optflags & FLAG_T)) { + TT.hw_timer_s = WATCHDOG_HW_TIMER_S_DEFAULT; +#if defined(WATCHDOG_DEBUG) + printf("using default hw_timer_s.\n"); +#endif + } + +#if defined(WATCHDOG_DEBUG) + printf("hw timer: %ld seconds\n", TT.hw_timer_s); + printf("sw timer: %ld seconds\n", TT.sw_timer_s); +#endif + + if (!(toys.optflags & FLAG_F)) { +#if defined(WATCHDOG_DEBUG) + printf("daemonizing. so long, foreground!\n"); +#endif + // Attempt to daemonize + rc = daemon(1, 1); + if ( rc ) { + perror_exit("failed to daemonize: %d", rc); + } + } + + // Intercept terminating signals so we can call our shutdown routine first. + if ( intercept_signals(safe_shutdown) ) { + perror_exit("failed to intercept desired signals: %d", rc); + } +#if defined(WATCHDOG_DEBUG) + printf("Successfully intercepted signals.\n"); +#endif + + TT.fd = open(watchdog_dev, O_WRONLY); + if ( TT.fd == -1 ) { + perror_exit("failed to open '%s'", watchdog_dev); + } + +#if defined(WDIOC_SETTIMEOUT) + // SETTIMEOUT takes time value in seconds: s = ms / (1000 ms/s) + hw_timer_sec = TT.hw_timer_s; + xioctl(TT.fd, WDIOC_SETTIMEOUT, (void *)&hw_timer_sec); +#endif // WDIOC_SETTIMEOUT + + // Now that we've got the watchdog device open, kick it periodically. + while (1) { + write(TT.fd, "\0", 1); + usleep(TT.sw_timer_s * 1000 * 1000); + } +} |