chiark / gitweb /
systemd: add hardware watchdog support
authorLennart Poettering <lennart@poettering.net>
Thu, 5 Apr 2012 20:08:10 +0000 (22:08 +0200)
committerLennart Poettering <lennart@poettering.net>
Thu, 5 Apr 2012 20:15:29 +0000 (22:15 +0200)
This adds minimal hardware watchdog support to PID 1. The idea is that
PID 1 supervises and watchdogs system services, while the hardware
watchdog is used to supervise PID 1.

This adds two hardware watchdog configuration options, for the runtime
watchdog and for a shutdown watchdog. The former is active during normal
operation, the latter only at reboots to ensure that if a clean reboot
times out we reboot nonetheless.

If the runtime watchdog is enabled PID 1 will automatically wake up at
half the configured interval and write to the watchdog daemon.

By default we enable the shutdown watchdog, but leave the runtime
watchdog disabled in order not to break independent hardware watchdog
daemons people might be using.

This is only the most basic hookup. If necessary we can later on hook
up the watchdog ping more closely with services deemed crucial.

13 files changed:
.gitignore
Makefile.am
TODO
man/systemd.conf.xml
src/dbus-manager.c
src/main.c
src/manager.c
src/manager.h
src/shutdown.c
src/system.conf
src/test-watchdog.c [new file with mode: 0644]
src/watchdog.c [new file with mode: 0644]
src/watchdog.h [new file with mode: 0644]

index 16a6f58..af68896 100644 (file)
@@ -1,3 +1,4 @@
+/test-watchdog
 /test-journal-send
 /systemd-multi-seat-x
 /systemd-cgtop
index 9d05c7c..5a8d22d 100644 (file)
@@ -229,7 +229,8 @@ noinst_PROGRAMS = \
        test-cgroup \
        test-env-replace \
        test-strv \
-       test-install
+       test-install \
+        test-watchdog
 
 dist_pkgsysconf_DATA = \
        src/system.conf \
@@ -612,6 +613,8 @@ libsystemd_core_la_SOURCES = \
        src/tcpwrap.h \
        src/cgroup-attr.c \
        src/cgroup-attr.h \
+        src/watchdog.c \
+        src/watchdog.h \
        src/sd-daemon.c \
        src/sd-id128.c \
        src/macro.h \
@@ -820,6 +823,14 @@ test_install_CFLAGS = \
 test_install_LDADD = \
        libsystemd-basic.la
 
+test_watchdog_SOURCES = \
+        src/test-watchdog.c \
+       src/watchdog.c \
+        src/watchdog.h
+
+test_watchdog_LDADD = \
+       libsystemd-basic.la
+
 systemd_initctl_SOURCES = \
        src/initctl.c \
        src/dbus-common.c
@@ -862,7 +873,9 @@ systemd_shutdownd_LDADD = \
 systemd_shutdown_SOURCES = \
        src/mount-setup.c \
        src/umount.c \
-       src/shutdown.c
+       src/shutdown.c \
+        src/watchdog.c \
+        src/watchdog.h
 
 systemd_shutdown_LDADD = \
        libsystemd-basic.la \
diff --git a/TODO b/TODO
index b1207ba..bee3b2b 100644 (file)
--- a/TODO
+++ b/TODO
@@ -85,8 +85,6 @@ Features:
 
 * There's currently no way to cancel fsck (used to be possible via C-c or c on the console)
 
-* hook up /dev/watchdog with main event loop for embedded, server uses
-
 * when dumping cgroup contents, include main/control PID of a service, explicitly
 
 * keep an eye on https://bugzilla.gnome.org/show_bug.cgi?id=670100
index ba144da..c789028 100644 (file)
                                 controllers in separate
                                 hierarchies.</para></listitem>
                         </varlistentry>
+
+                        <varlistentry>
+                                <term><varname>RuntimeWatchdogSec=</varname></term>
+                                <term><varname>ShutdownWatchdogSec=</varname></term>
+
+                                <listitem><para>Configure the hardware
+                                watchdog at runtime and at
+                                reboot. Takes a timeout value in
+                                seconds (or in other time units if
+                                suffixed with <literal>ms</literal>,
+                                <literal>min</literal>,
+                                <literal>h</literal>,
+                                <literal>d</literal>,
+                                <literal>w</literal>). If
+                                <varname>RuntimeWatchdogSec=</varname>
+                                is set to a non-zero value the
+                                watchdog hardware
+                                (<filename>/dev/watchdog</filename>)
+                                will be programmed to automatically
+                                reboot the system if it is not
+                                contacted within the specified timeout
+                                interval. The system manager will
+                                ensure to contact it at least once in
+                                half the specified timeout
+                                interval. This feature requires a
+                                hardware watchdog device to be
+                                present, as it is commonly the case in
+                                embedded and server systems. Not all
+                                hardware watchdogs allow configuration
+                                of the reboot timeout, in which case
+                                the closest available timeout is
+                                picked. <varname>ShutdownWatchdogSec=</varname>
+                                may be used to configure the hardware
+                                watchdog when the system is asked to
+                                reboot. It works as a safety net to
+                                ensure that the reboot takes place
+                                even if a clean reboot attempt times
+                                out. By default
+                                <varname>RuntimeWatchdogSec=</varname>
+                                defaults to 0 (off), and
+                                <varname>ShutdownWatchdogSec=</varname>
+                                to 10min. These settings have no
+                                effect if a hardware watchdog is not
+                                available.</para></listitem>
+                        </varlistentry>
                 </variablelist>
         </refsect1>
 
index 6d272cb..0a6e55d 100644 (file)
         "  <property name=\"SwapAuto\" type=\"b\" access=\"read\"/>\n"  \
         "  <property name=\"DefaultControllers\" type=\"as\" access=\"read\"/>\n" \
         "  <property name=\"DefaultStandardOutput\" type=\"s\" access=\"read\"/>\n" \
-        "  <property name=\"DefaultStandardError\" type=\"s\" access=\"read\"/>\n"
+        "  <property name=\"DefaultStandardError\" type=\"s\" access=\"read\"/>\n" \
+        "  <property name=\"RuntimeWatchdogUSec\" type=\"s\" access=\"read\"/>\n" \
+        "  <property name=\"ShutdownWatchdogUSec\" type=\"s\" access=\"read\"/>\n"
 
 #ifdef HAVE_SYSV_COMPAT
 #define BUS_MANAGER_INTERFACE_PROPERTIES_SYSV                           \
@@ -491,7 +493,10 @@ static int bus_manager_send_unit_files_changed(Manager *m) {
         return r;
 }
 
-static const char systemd_property_string[] = PACKAGE_STRING "\0" DISTRIBUTION "\0" SYSTEMD_FEATURES;
+static const char systemd_property_string[] =
+        PACKAGE_STRING "\0"
+        DISTRIBUTION "\0"
+        SYSTEMD_FEATURES;
 
 static const BusProperty bus_systemd_properties[] = {
         { "Version",       bus_property_append_string,    "s",  0                                             },
@@ -502,7 +507,7 @@ static const BusProperty bus_systemd_properties[] = {
 
 static const BusProperty bus_manager_properties[] = {
         { "RunningAs",     bus_manager_append_running_as,          "s", offsetof(Manager, running_as)                  },
-        { "Tainted",       bus_manager_append_tainted,             "s", 0 },
+        { "Tainted",       bus_manager_append_tainted,             "s", 0                                              },
         { "InitRDTimestamp", bus_property_append_uint64,           "t", offsetof(Manager, initrd_timestamp.realtime)   },
         { "InitRDTimestampMonotonic", bus_property_append_uint64,  "t", offsetof(Manager, initrd_timestamp.monotonic)  },
         { "StartupTimestamp", bus_property_append_uint64,          "t", offsetof(Manager, startup_timestamp.realtime)  },
@@ -511,11 +516,11 @@ static const BusProperty bus_manager_properties[] = {
         { "FinishTimestampMonotonic", bus_property_append_uint64,  "t", offsetof(Manager, finish_timestamp.monotonic)  },
         { "LogLevel",      bus_manager_append_log_level,           "s", 0,                                             0, bus_manager_set_log_level },
         { "LogTarget",     bus_manager_append_log_target,          "s", 0,                                             0, bus_manager_set_log_target },
-        { "NNames",        bus_manager_append_n_names,             "u", 0 },
-        { "NJobs",         bus_manager_append_n_jobs,              "u", 0 },
+        { "NNames",        bus_manager_append_n_names,             "u", 0                                              },
+        { "NJobs",         bus_manager_append_n_jobs,              "u", 0                                              },
         { "NInstalledJobs",bus_property_append_uint32,             "u", offsetof(Manager, n_installed_jobs)            },
         { "NFailedJobs",   bus_property_append_uint32,             "u", offsetof(Manager, n_failed_jobs)               },
-        { "Progress",      bus_manager_append_progress,            "d", 0 },
+        { "Progress",      bus_manager_append_progress,            "d", 0                                              },
         { "Environment",   bus_property_append_strv,              "as", offsetof(Manager, environment),                true },
         { "ConfirmSpawn",  bus_property_append_bool,               "b", offsetof(Manager, confirm_spawn)               },
         { "ShowStatus",    bus_property_append_bool,               "b", offsetof(Manager, show_status)                 },
@@ -527,6 +532,8 @@ static const BusProperty bus_manager_properties[] = {
         { "DefaultControllers", bus_property_append_strv,         "as", offsetof(Manager, default_controllers),        true },
         { "DefaultStandardOutput", bus_manager_append_exec_output, "s", offsetof(Manager, default_std_output)          },
         { "DefaultStandardError",  bus_manager_append_exec_output, "s", offsetof(Manager, default_std_error)           },
+        { "RuntimeWatchdogUSec", bus_property_append_usec,         "t", offsetof(Manager, runtime_watchdog),           },
+        { "ShutdownWatchdogUSec", bus_property_append_usec,        "t", offsetof(Manager, shutdown_watchdog),          },
 #ifdef HAVE_SYSV_COMPAT
         { "SysVConsole",   bus_property_append_bool,               "b", offsetof(Manager, sysv_console)                },
         { "SysVInitPath",  bus_property_append_strv,              "as", offsetof(Manager, lookup_paths.sysvinit_path), true },
index 7ae8841..40be2b2 100644 (file)
@@ -54,6 +54,7 @@
 #include "strv.h"
 #include "def.h"
 #include "virt.h"
+#include "watchdog.h"
 
 static enum {
         ACTION_RUN,
@@ -80,6 +81,8 @@ static char **arg_default_controllers = NULL;
 static char ***arg_join_controllers = NULL;
 static ExecOutput arg_default_std_output = EXEC_OUTPUT_JOURNAL;
 static ExecOutput arg_default_std_error = EXEC_OUTPUT_INHERIT;
+static usec_t arg_runtime_watchdog = 0;
+static usec_t arg_shutdown_watchdog = 10 * USEC_PER_MINUTE;
 
 static FILE* serialization = NULL;
 
@@ -660,6 +663,8 @@ static int parse_config_file(void) {
                 { "Manager", "DefaultStandardOutput", config_parse_output,       0, &arg_default_std_output  },
                 { "Manager", "DefaultStandardError",  config_parse_output,       0, &arg_default_std_error   },
                 { "Manager", "JoinControllers",       config_parse_join_controllers, 0, &arg_join_controllers },
+                { "Manager", "RuntimeWatchdogSec",    config_parse_usec,         0, &arg_runtime_watchdog    },
+                { "Manager", "ShutdownWatchdogSec",   config_parse_usec,         0, &arg_shutdown_watchdog   },
                 { NULL, NULL, NULL, 0, NULL }
         };
 
@@ -1163,6 +1168,7 @@ int main(int argc, char *argv[]) {
         bool is_reexec = false;
         int j;
         bool loaded_policy = false;
+        bool arm_reboot_watchdog = false;
 
 #ifdef HAVE_SYSV_COMPAT
         if (getpid() != 1 && strstr(program_invocation_short_name, "init")) {
@@ -1391,7 +1397,11 @@ int main(int argc, char *argv[]) {
                 test_cgroups();
         }
 
-        if ((r = manager_new(arg_running_as, &m)) < 0) {
+        if (arg_running_as == MANAGER_SYSTEM && arg_runtime_watchdog > 0)
+                watchdog_set_timeout(&arg_runtime_watchdog);
+
+        r = manager_new(arg_running_as, &m);
+        if (r < 0) {
                 log_error("Failed to allocate manager object: %s", strerror(-r));
                 goto finish;
         }
@@ -1404,6 +1414,8 @@ int main(int argc, char *argv[]) {
         m->swap_auto = arg_swap_auto;
         m->default_std_output = arg_default_std_output;
         m->default_std_error = arg_default_std_error;
+        m->runtime_watchdog = arg_runtime_watchdog;
+        m->shutdown_watchdog = arg_shutdown_watchdog;
 
         if (dual_timestamp_is_set(&initrd_timestamp))
                 m->initrd_timestamp = initrd_timestamp;
@@ -1415,7 +1427,8 @@ int main(int argc, char *argv[]) {
 
         before_startup = now(CLOCK_MONOTONIC);
 
-        if ((r = manager_startup(m, serialization, fds)) < 0)
+        r = manager_startup(m, serialization, fds);
+        if (r < 0)
                 log_error("Failed to fully start up daemon: %s", strerror(-r));
 
         if (fds) {
@@ -1438,7 +1451,8 @@ int main(int argc, char *argv[]) {
 
                 log_debug("Activating default unit: %s", arg_default_unit);
 
-                if ((r = manager_load_unit(m, arg_default_unit, NULL, &error, &target)) < 0) {
+                r = manager_load_unit(m, arg_default_unit, NULL, &error, &target);
+                if (r < 0) {
                         log_error("Failed to load default target: %s", bus_error(&error, r));
                         dbus_error_free(&error);
                 } else if (target->load_state == UNIT_ERROR)
@@ -1449,7 +1463,8 @@ int main(int argc, char *argv[]) {
                 if (!target || target->load_state != UNIT_LOADED) {
                         log_info("Trying to load rescue target...");
 
-                        if ((r = manager_load_unit(m, SPECIAL_RESCUE_TARGET, NULL, &error, &target)) < 0) {
+                        r = manager_load_unit(m, SPECIAL_RESCUE_TARGET, NULL, &error, &target);
+                        if (r < 0) {
                                 log_error("Failed to load rescue target: %s", bus_error(&error, r));
                                 dbus_error_free(&error);
                                 goto finish;
@@ -1491,7 +1506,8 @@ int main(int argc, char *argv[]) {
         }
 
         for (;;) {
-                if ((r = manager_loop(m)) < 0) {
+                r = manager_loop(m);
+                if (r < 0) {
                         log_error("Failed to run mainloop: %s", strerror(-r));
                         goto finish;
                 }
@@ -1505,7 +1521,8 @@ int main(int argc, char *argv[]) {
 
                 case MANAGER_RELOAD:
                         log_info("Reloading.");
-                        if ((r = manager_reload(m)) < 0)
+                        r = manager_reload(m);
+                        if (r < 0)
                                 log_error("Failed to reload: %s", strerror(-r));
                         break;
 
@@ -1529,6 +1546,7 @@ int main(int argc, char *argv[]) {
                         };
 
                         assert_se(shutdown_verb = table[m->exit_code]);
+                        arm_reboot_watchdog = m->exit_code == MANAGER_REBOOT;
 
                         log_notice("Shutting down.");
                         goto finish;
@@ -1615,13 +1633,33 @@ finish:
                 fdset_free(fds);
 
         if (shutdown_verb) {
+                char e[32];
+
                 const char * command_line[] = {
                         SYSTEMD_SHUTDOWN_BINARY_PATH,
                         shutdown_verb,
                         NULL
                 };
+                const char * env_block[] = {
+                        NULL,
+                        NULL
+                };
 
-                execv(SYSTEMD_SHUTDOWN_BINARY_PATH, (char **) command_line);
+                if (arm_reboot_watchdog && arg_shutdown_watchdog > 0) {
+                        /* If we reboot let's set the shutdown
+                         * watchdog and tell the shutdown binary to
+                         * repeatedly ping it */
+                        watchdog_set_timeout(&arg_shutdown_watchdog);
+                        watchdog_close(false);
+
+                        /* Tell the binary how often to ping */
+                        snprintf(e, sizeof(e), "WATCHDOG_USEC=%llu", (unsigned long long) arg_shutdown_watchdog);
+                        char_array_0(e);
+                        env_block[0] = e;
+                } else
+                        watchdog_close(true);
+
+                execve(SYSTEMD_SHUTDOWN_BINARY_PATH, (char **) command_line, (char**) env_block);
                 log_error("Failed to execute shutdown binary, freezing: %m");
         }
 
index 74bd740..be47766 100644 (file)
@@ -61,6 +61,7 @@
 #include "bus-errors.h"
 #include "exit-status.h"
 #include "virt.h"
+#include "watchdog.h"
 
 /* As soon as 16 units are in our GC queue, make sure to run a gc sweep */
 #define GC_QUEUE_ENTRIES_MAX 16
@@ -2433,6 +2434,7 @@ static int process_event(Manager *m, struct epoll_event *ev) {
 
 int manager_loop(Manager *m) {
         int r;
+        int wait_msec = -1;
 
         RATELIMIT_DEFINE(rl, 1*USEC_PER_SEC, 50000);
 
@@ -2447,17 +2449,29 @@ int manager_loop(Manager *m) {
 
         /* There might still be some zombies hanging around from
          * before we were exec()'ed. Leat's reap them */
-        if ((r = manager_dispatch_sigchld(m)) < 0)
+        r = manager_dispatch_sigchld(m);
+        if (r < 0)
                 return r;
 
+        /* Sleep for half the watchdog time */
+        if (m->runtime_watchdog > 0 && m->running_as == MANAGER_SYSTEM)  {
+                wait_msec = (int) (m->runtime_watchdog / 2 / USEC_PER_MSEC);
+                if (wait_msec <= 0)
+                        wait_msec = 1;
+        }
+
         while (m->exit_code == MANAGER_RUNNING) {
                 struct epoll_event event;
                 int n;
 
+                if (wait_msec >= 0)
+                        watchdog_ping();
+
                 if (!ratelimit_test(&rl)) {
                         /* Yay, something is going seriously wrong, pause a little */
                         log_warning("Looping too fast. Throttling execution a little.");
                         sleep(1);
+                        continue;
                 }
 
                 if (manager_dispatch_load_queue(m) > 0)
@@ -2481,17 +2495,20 @@ int manager_loop(Manager *m) {
                 if (swap_dispatch_reload(m) > 0)
                         continue;
 
-                if ((n = epoll_wait(m->epoll_fd, &event, 1, -1)) < 0) {
+                n = epoll_wait(m->epoll_fd, &event, 1, wait_msec);
+                if (n < 0) {
 
                         if (errno == EINTR)
                                 continue;
 
                         return -errno;
-                }
+                } else if (n == 0)
+                        continue;
 
                 assert(n == 1);
 
-                if ((r = process_event(m, &event)) < 0)
+                r = process_event(m, &event);
+                if (r < 0)
                         return r;
         }
 
index a9d08f0..9ecc926 100644 (file)
@@ -144,6 +144,9 @@ struct Manager {
         char **environment;
         char **default_controllers;
 
+        usec_t runtime_watchdog;
+        usec_t shutdown_watchdog;
+
         dual_timestamp initrd_timestamp;
         dual_timestamp startup_timestamp;
         dual_timestamp finish_timestamp;
index d157e0f..9f65b1d 100644 (file)
@@ -42,6 +42,7 @@
 #include "umount.h"
 #include "util.h"
 #include "virt.h"
+#include "watchdog.h"
 
 #define TIMEOUT_USEC (5 * USEC_PER_SEC)
 #define FINALIZE_ATTEMPTS 50
@@ -306,7 +307,7 @@ int main(int argc, char *argv[]) {
         int cmd, r;
         unsigned retries;
         bool need_umount = true, need_swapoff = true, need_loop_detach = true, need_dm_detach = true;
-        bool killed_everbody = false, in_container;
+        bool killed_everbody = false, in_container, use_watchdog = false;
 
         log_parse_environment();
         log_set_target(LOG_TARGET_CONSOLE); /* syslog will die if not gone yet */
@@ -342,6 +343,8 @@ int main(int argc, char *argv[]) {
                 goto error;
         }
 
+        use_watchdog = !!getenv("WATCHDOG_USEC");
+
         /* lock us into memory */
         if (mlockall(MCL_CURRENT|MCL_FUTURE) != 0)
                 log_warning("Cannot lock process memory: %m");
@@ -359,6 +362,9 @@ int main(int argc, char *argv[]) {
         for (retries = 0; retries < FINALIZE_ATTEMPTS; retries++) {
                 bool changed = false;
 
+                if (use_watchdog)
+                        watchdog_ping();
+
                 if (need_umount) {
                         log_info("Unmounting file systems.");
                         r = umount_all(&changed);
index 33d09bc..36eac07 100644 (file)
@@ -24,3 +24,5 @@
 #DefaultStandardOutput=journal
 #DefaultStandardError=inherit
 #JoinControllers=cpu,cpuacct
+#RuntimeWatchdog=0
+#ShutdownWatchdog=10min
diff --git a/src/test-watchdog.c b/src/test-watchdog.c
new file mode 100644 (file)
index 0000000..d53fddb
--- /dev/null
@@ -0,0 +1,51 @@
+/*-*- 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 <unistd.h>
+#include <string.h>
+
+#include "watchdog.h"
+#include "log.h"
+
+int main(int argc, char *argv[]) {
+        usec_t t = 10 * USEC_PER_SEC;
+        unsigned i;
+        int r;
+
+        log_set_max_level(LOG_DEBUG);
+        log_parse_environment();
+
+        r = watchdog_set_timeout(&t);
+        if (r < 0)
+                log_warning("Failed to open watchdog: %s", strerror(-r));
+
+        for (i = 0; i < 5; i++) {
+                log_info("Pinging...");
+                r = watchdog_ping();
+                if (r < 0)
+                        log_warning("Failed to ping watchdog: %s", strerror(-r));
+
+                usleep(t/2);
+        }
+
+        watchdog_close(true);
+        return 0;
+}
diff --git a/src/watchdog.c b/src/watchdog.c
new file mode 100644 (file)
index 0000000..9625e15
--- /dev/null
@@ -0,0 +1,166 @@
+/*-*- 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) {
+
+        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)
+                return open_watchdog();
+        else
+                return update_timeout();
+
+        *usec = watchdog_timeout;
+}
+
+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;
+}
diff --git a/src/watchdog.h b/src/watchdog.h
new file mode 100644 (file)
index 0000000..5ba7079
--- /dev/null
@@ -0,0 +1,31 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#ifndef foowatchdoghfoo
+#define foowatchdoghfoo
+
+/***
+  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 "util.h"
+
+int watchdog_set_timeout(usec_t *usec);
+int watchdog_ping(void);
+void watchdog_close(bool disarm);
+
+#endif