diff options
Diffstat (limited to 'src/shared/watchdog.c')
| -rw-r--r-- | src/shared/watchdog.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/src/shared/watchdog.c b/src/shared/watchdog.c new file mode 100644 index 0000000000..13265e7692 --- /dev/null +++ b/src/shared/watchdog.c @@ -0,0 +1,169 @@ +/*-*- 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 Lesser General Public License as published by + the Free Software Foundation; either version 2.1 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser 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; +} |