/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** This file is part of systemd. Copyright 2012 Lennart Poettering systemd is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. systemd is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with systemd; If not, see <http://www.gnu.org/licenses/>. ***/ #include <sys/ioctl.h> #include <errno.h> #include <fcntl.h> #include <unistd.h> #include <linux/watchdog.h> #include "watchdog.h" #include "log.h" static int watchdog_fd = -1; static usec_t watchdog_timeout = (usec_t) -1; static int update_timeout(void) { int r; if (watchdog_fd < 0) return 0; if (watchdog_timeout == (usec_t) -1) return 0; else if (watchdog_timeout == 0) { int flags; flags = WDIOS_DISABLECARD; r = ioctl(watchdog_fd, WDIOC_SETOPTIONS, &flags); if (r < 0) { log_warning("Failed to disable hardware watchdog: %m"); return -errno; } } else { int sec, flags; char buf[FORMAT_TIMESPAN_MAX]; sec = (int) ((watchdog_timeout + USEC_PER_SEC - 1) / USEC_PER_SEC); r = ioctl(watchdog_fd, WDIOC_SETTIMEOUT, &sec); if (r < 0) { log_warning("Failed to set timeout to %is: %m", sec); return -errno; } watchdog_timeout = (usec_t) sec * USEC_PER_SEC; log_info("Set hardware watchdog to %s.", format_timespan(buf, sizeof(buf), watchdog_timeout)); flags = WDIOS_ENABLECARD; r = ioctl(watchdog_fd, WDIOC_SETOPTIONS, &flags); if (r < 0) { log_warning("Failed to enable hardware watchdog: %m"); return -errno; } r = ioctl(watchdog_fd, WDIOC_KEEPALIVE, 0); if (r < 0) { log_warning("Failed to ping hardware watchdog: %m"); return -errno; } } return 0; } static int open_watchdog(void) { struct watchdog_info ident; if (watchdog_fd >= 0) return 0; watchdog_fd = open("/dev/watchdog", O_WRONLY|O_CLOEXEC); if (watchdog_fd < 0) return -errno; if (ioctl(watchdog_fd, WDIOC_GETSUPPORT, &ident) >= 0) log_info("Hardware watchdog '%s', version %x", ident.identity, ident.firmware_version); return update_timeout(); } int watchdog_set_timeout(usec_t *usec) { int r; watchdog_timeout = *usec; /* If we didn't open the watchdog yet and didn't get any * explicit timeout value set, don't do anything */ if (watchdog_fd < 0 && watchdog_timeout == (usec_t) -1) return 0; if (watchdog_fd < 0) r = open_watchdog(); else r = update_timeout(); *usec = watchdog_timeout; return r; } int watchdog_ping(void) { int r; if (watchdog_fd < 0) { r = open_watchdog(); if (r < 0) return r; } r = ioctl(watchdog_fd, WDIOC_KEEPALIVE, 0); if (r < 0) { log_warning("Failed to ping hardware watchdog: %m"); return -errno; } return 0; } void watchdog_close(bool disarm) { int r; if (watchdog_fd < 0) return; if (disarm) { int flags; /* Explicitly disarm it */ flags = WDIOS_DISABLECARD; r = ioctl(watchdog_fd, WDIOC_SETOPTIONS, &flags); if (r < 0) log_warning("Failed to disable hardware watchdog: %m"); /* To be sure, use magic close logic, too */ for (;;) { static const char v = 'V'; if (write(watchdog_fd, &v, 1) > 0) break; if (errno != EINTR) { log_error("Failed to disarm watchdog timer: %m"); break; } } } close_nointr_nofail(watchdog_fd); watchdog_fd = -1; }