1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2012 Lennart Poettering
8 systemd is free software; you can redistribute it and/or modify it
9 under the terms of the GNU Lesser General Public License as published by
10 the Free Software Foundation; either version 2.1 of the License, or
11 (at your option) any later version.
13 systemd is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 Lesser General Public License for more details.
18 You should have received a copy of the GNU Lesser General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
22 #include <sys/ioctl.h>
26 #include <linux/watchdog.h>
31 static int watchdog_fd = -1;
32 static usec_t watchdog_timeout = (usec_t) -1;
34 static int update_timeout(void) {
40 if (watchdog_timeout == (usec_t) -1)
42 else if (watchdog_timeout == 0) {
45 flags = WDIOS_DISABLECARD;
46 r = ioctl(watchdog_fd, WDIOC_SETOPTIONS, &flags);
48 log_warning("Failed to disable hardware watchdog: %m");
53 char buf[FORMAT_TIMESPAN_MAX];
55 sec = (int) ((watchdog_timeout + USEC_PER_SEC - 1) / USEC_PER_SEC);
56 r = ioctl(watchdog_fd, WDIOC_SETTIMEOUT, &sec);
58 log_warning("Failed to set timeout to %is: %m", sec);
62 watchdog_timeout = (usec_t) sec * USEC_PER_SEC;
63 log_info("Set hardware watchdog to %s.", format_timespan(buf, sizeof(buf), watchdog_timeout, 0));
65 flags = WDIOS_ENABLECARD;
66 r = ioctl(watchdog_fd, WDIOC_SETOPTIONS, &flags);
68 log_warning("Failed to enable hardware watchdog: %m");
72 r = ioctl(watchdog_fd, WDIOC_KEEPALIVE, 0);
74 log_warning("Failed to ping hardware watchdog: %m");
82 static int open_watchdog(void) {
83 struct watchdog_info ident;
88 watchdog_fd = open("/dev/watchdog", O_WRONLY|O_CLOEXEC);
92 if (ioctl(watchdog_fd, WDIOC_GETSUPPORT, &ident) >= 0)
93 log_info("Hardware watchdog '%s', version %x",
95 ident.firmware_version);
97 return update_timeout();
100 int watchdog_set_timeout(usec_t *usec) {
103 watchdog_timeout = *usec;
105 /* If we didn't open the watchdog yet and didn't get any
106 * explicit timeout value set, don't do anything */
107 if (watchdog_fd < 0 && watchdog_timeout == (usec_t) -1)
113 r = update_timeout();
115 *usec = watchdog_timeout;
120 int watchdog_ping(void) {
123 if (watchdog_fd < 0) {
129 r = ioctl(watchdog_fd, WDIOC_KEEPALIVE, 0);
131 log_warning("Failed to ping hardware watchdog: %m");
138 void watchdog_close(bool disarm) {
147 /* Explicitly disarm it */
148 flags = WDIOS_DISABLECARD;
149 r = ioctl(watchdog_fd, WDIOC_SETOPTIONS, &flags);
151 log_warning("Failed to disable hardware watchdog: %m");
153 /* To be sure, use magic close logic, too */
155 static const char v = 'V';
157 if (write(watchdog_fd, &v, 1) > 0)
160 if (errno != EINTR) {
161 log_error("Failed to disarm watchdog timer: %m");
167 close_nointr_nofail(watchdog_fd);