Systemd/src/shared/watchdog.c
Lennart Poettering 0c69794138 tree-wide: remove Lennart's copyright lines
These lines are generally out-of-date, incomplete and unnecessary. With
SPDX and git repository much more accurate and fine grained information
about licensing and authorship is available, hence let's drop the
per-file copyright notice. Of course, removing copyright lines of others
is problematic, hence this commit only removes my own lines and leaves
all others untouched. It might be nicer if sooner or later those could
go away too, making git the only and accurate source of authorship
information.
2018-06-14 10:20:20 +02:00

155 lines
4.5 KiB
C

/* SPDX-License-Identifier: LGPL-2.1+ */
#include <errno.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <syslog.h>
#include <unistd.h>
#include <linux/watchdog.h>
#include "fd-util.h"
#include "log.h"
#include "string-util.h"
#include "time-util.h"
#include "watchdog.h"
static int watchdog_fd = -1;
static char *watchdog_device = NULL;
static usec_t watchdog_timeout = USEC_INFINITY;
static int update_timeout(void) {
int r;
if (watchdog_fd < 0)
return 0;
if (watchdog_timeout == USEC_INFINITY)
return 0;
else if (watchdog_timeout == 0) {
int flags;
flags = WDIOS_DISABLECARD;
r = ioctl(watchdog_fd, WDIOC_SETOPTIONS, &flags);
if (r < 0)
return log_warning_errno(errno, "Failed to disable hardware watchdog: %m");
} else {
int sec, flags;
char buf[FORMAT_TIMESPAN_MAX];
sec = (int) DIV_ROUND_UP(watchdog_timeout, USEC_PER_SEC);
r = ioctl(watchdog_fd, WDIOC_SETTIMEOUT, &sec);
if (r < 0)
return log_warning_errno(errno, "Failed to set timeout to %is: %m", sec);
watchdog_timeout = (usec_t) sec * USEC_PER_SEC;
log_info("Set hardware watchdog to %s.", format_timespan(buf, sizeof(buf), watchdog_timeout, 0));
flags = WDIOS_ENABLECARD;
r = ioctl(watchdog_fd, WDIOC_SETOPTIONS, &flags);
if (r < 0) {
/* ENOTTY means the watchdog is always enabled so we're fine */
log_full(errno == ENOTTY ? LOG_DEBUG : LOG_WARNING,
"Failed to enable hardware watchdog: %m");
if (errno != ENOTTY)
return -errno;
}
r = ioctl(watchdog_fd, WDIOC_KEEPALIVE, 0);
if (r < 0)
return log_warning_errno(errno, "Failed to ping hardware watchdog: %m");
}
return 0;
}
static int open_watchdog(void) {
struct watchdog_info ident;
if (watchdog_fd >= 0)
return 0;
watchdog_fd = open(watchdog_device ?: "/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_device(char *path) {
return free_and_strdup(&watchdog_device, path);
}
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_INFINITY)
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)
return log_warning_errno(errno, "Failed to ping hardware watchdog: %m");
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_errno(errno, "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_errno(errno, "Failed to disarm watchdog timer: %m");
break;
}
}
}
watchdog_fd = safe_close(watchdog_fd);
}