1fedf13839
The file descriptor was opened with O_CLOEXEC, so in practice this doesn't change too much, but it seems cleaner to always close the old fd when changing the device path.
164 lines
4.6 KiB
C
164 lines
4.6 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#include <errno.h>
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#include <fcntl.h>
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#include <sys/ioctl.h>
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#include <syslog.h>
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#include <unistd.h>
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#include <linux/watchdog.h>
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#include "fd-util.h"
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#include "log.h"
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#include "string-util.h"
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#include "time-util.h"
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#include "watchdog.h"
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static int watchdog_fd = -1;
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static char *watchdog_device = NULL;
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static usec_t watchdog_timeout = USEC_INFINITY;
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static int update_timeout(void) {
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int r;
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if (watchdog_fd < 0)
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return 0;
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if (watchdog_timeout == USEC_INFINITY)
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return 0;
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else if (watchdog_timeout == 0) {
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int flags;
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flags = WDIOS_DISABLECARD;
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r = ioctl(watchdog_fd, WDIOC_SETOPTIONS, &flags);
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if (r < 0)
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return log_warning_errno(errno, "Failed to disable hardware watchdog: %m");
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} else {
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int sec, flags;
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char buf[FORMAT_TIMESPAN_MAX];
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sec = (int) DIV_ROUND_UP(watchdog_timeout, USEC_PER_SEC);
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r = ioctl(watchdog_fd, WDIOC_SETTIMEOUT, &sec);
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if (r < 0)
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return log_warning_errno(errno, "Failed to set timeout to %is: %m", sec);
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watchdog_timeout = (usec_t) sec * USEC_PER_SEC;
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log_info("Set hardware watchdog to %s.", format_timespan(buf, sizeof(buf), watchdog_timeout, 0));
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flags = WDIOS_ENABLECARD;
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r = ioctl(watchdog_fd, WDIOC_SETOPTIONS, &flags);
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if (r < 0) {
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/* ENOTTY means the watchdog is always enabled so we're fine */
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log_full(errno == ENOTTY ? LOG_DEBUG : LOG_WARNING,
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"Failed to enable hardware watchdog: %m");
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if (errno != ENOTTY)
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return -errno;
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}
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r = ioctl(watchdog_fd, WDIOC_KEEPALIVE, 0);
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if (r < 0)
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return log_warning_errno(errno, "Failed to ping hardware watchdog: %m");
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}
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return 0;
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}
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static int open_watchdog(void) {
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struct watchdog_info ident;
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if (watchdog_fd >= 0)
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return 0;
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watchdog_fd = open(watchdog_device ?: "/dev/watchdog",
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O_WRONLY|O_CLOEXEC);
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if (watchdog_fd < 0)
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return -errno;
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if (ioctl(watchdog_fd, WDIOC_GETSUPPORT, &ident) >= 0)
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log_info("Hardware watchdog '%s', version %x",
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ident.identity,
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ident.firmware_version);
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return update_timeout();
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}
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int watchdog_set_device(char *path) {
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int r;
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r = free_and_strdup(&watchdog_device, path);
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if (r < 0)
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return r;
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if (r > 0) /* watchdog_device changed */
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watchdog_fd = safe_close(watchdog_fd);
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return r;
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}
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int watchdog_set_timeout(usec_t *usec) {
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int r;
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watchdog_timeout = *usec;
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/* If we didn't open the watchdog yet and didn't get any
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* explicit timeout value set, don't do anything */
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if (watchdog_fd < 0 && watchdog_timeout == USEC_INFINITY)
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return 0;
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if (watchdog_fd < 0)
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r = open_watchdog();
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else
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r = update_timeout();
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*usec = watchdog_timeout;
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return r;
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}
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int watchdog_ping(void) {
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int r;
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if (watchdog_fd < 0) {
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r = open_watchdog();
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if (r < 0)
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return r;
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}
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r = ioctl(watchdog_fd, WDIOC_KEEPALIVE, 0);
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if (r < 0)
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return log_warning_errno(errno, "Failed to ping hardware watchdog: %m");
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return 0;
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}
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void watchdog_close(bool disarm) {
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int r;
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if (watchdog_fd < 0)
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return;
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if (disarm) {
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int flags;
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/* Explicitly disarm it */
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flags = WDIOS_DISABLECARD;
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r = ioctl(watchdog_fd, WDIOC_SETOPTIONS, &flags);
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if (r < 0)
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log_warning_errno(errno, "Failed to disable hardware watchdog: %m");
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/* To be sure, use magic close logic, too */
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for (;;) {
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static const char v = 'V';
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if (write(watchdog_fd, &v, 1) > 0)
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break;
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if (errno != EINTR) {
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log_error_errno(errno, "Failed to disarm watchdog timer: %m");
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break;
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}
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}
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}
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watchdog_fd = safe_close(watchdog_fd);
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}
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