[LEDE-DEV] [PATCH procd] watchdog: add support for starting/stopping kernel watchdog

[John Crispin]

On 19/06/17 11:14, Hans Dedecker wrote:
> Extend the ubus watchdog cmd with the parameter magicclose; when set and
> in case the stopped parameter is enabled the kernel watchdog will be stopped
> by first sending the magic character 'V' followed by a close of the watchdog
> fd. In case stopped is set to disabled the watchdog fd will be created again.
>
> Signed-off-by: Hans Dedecker <dedeckeh at gmail.com>
Acked-by: John Crispin <john at phrozen.org>

feel free to merge the patch and update trunk

     John

> ---
>   system.c   |  6 +++++
>   watchdog.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++---------------
>   watchdog.h | 10 +++++++++
>   3 files changed, 74 insertions(+), 18 deletions(-)
>
> diff --git a/system.c b/system.c
> index 4bbceee..a5d197e 100644
> --- a/system.c
> +++ b/system.c
> @@ -245,6 +245,7 @@ static int system_reboot(struct ubus_context *ctx, struct ubus_object *obj,
>   enum {
>   	WDT_FREQUENCY,
>   	WDT_TIMEOUT,
> +	WDT_MAGICCLOSE,
>   	WDT_STOP,
>   	__WDT_MAX
>   };
> @@ -252,6 +253,7 @@ enum {
>   static const struct blobmsg_policy watchdog_policy[__WDT_MAX] = {
>   	[WDT_FREQUENCY] = { .name = "frequency", .type = BLOBMSG_TYPE_INT32 },
>   	[WDT_TIMEOUT] = { .name = "timeout", .type = BLOBMSG_TYPE_INT32 },
> +	[WDT_MAGICCLOSE] = { .name = "magicclose", .type = BLOBMSG_TYPE_BOOL },
>   	[WDT_STOP] = { .name = "stop", .type = BLOBMSG_TYPE_BOOL },
>   };
>   
> @@ -286,6 +288,9 @@ static int watchdog_set(struct ubus_context *ctx, struct ubus_object *obj,
>   		 watchdog_timeout(timeout);
>   	}
>   
> +	if (tb[WDT_MAGICCLOSE])
> +		watchdog_set_magicclose(blobmsg_get_bool(tb[WDT_MAGICCLOSE]));
> +
>   	if (tb[WDT_STOP])
>   		watchdog_set_stopped(blobmsg_get_bool(tb[WDT_STOP]));
>   
> @@ -300,6 +305,7 @@ static int watchdog_set(struct ubus_context *ctx, struct ubus_object *obj,
>   	blobmsg_add_string(&b, "status", status);
>   	blobmsg_add_u32(&b, "timeout", watchdog_timeout(0));
>   	blobmsg_add_u32(&b, "frequency", watchdog_frequency(0));
> +	blobmsg_add_u8(&b, "magicclose", watchdog_get_magicclose());
>   	ubus_send_reply(ctx, req, b.head);
>   
>   	return 0;
> diff --git a/watchdog.c b/watchdog.c
> index 780b321..97c8337 100644
> --- a/watchdog.c
> +++ b/watchdog.c
> @@ -31,6 +31,7 @@
>   static struct uloop_timeout wdt_timeout;
>   static int wdt_fd = -1;
>   static int wdt_frequency = 5;
> +static bool wdt_magicclose = false;
>   
>   void watchdog_ping(void)
>   {
> @@ -45,12 +46,66 @@ static void watchdog_timeout_cb(struct uloop_timeout *t)
>   	uloop_timeout_set(t, wdt_frequency * 1000);
>   }
>   
> +static int watchdog_open(bool cloexec)
> +{
> +	char *env = getenv("WDTFD");
> +
> +	if (wdt_fd >= 0)
> +		return wdt_fd;
> +
> +	if (env) {
> +		DEBUG(2, "Watchdog handover: fd=%s\n", env);
> +		wdt_fd = atoi(env);
> +		unsetenv("WDTFD");
> +	} else {
> +		wdt_fd = open(WDT_PATH, O_WRONLY);
> +	}
> +
> +	if (wdt_fd < 0)
> +		return wdt_fd;
> +
> +	if (cloexec)
> +		fcntl(wdt_fd, F_SETFD, fcntl(wdt_fd, F_GETFD) | FD_CLOEXEC);
> +
> +	return wdt_fd;
> +}
> +
> +static void watchdog_close(void)
> +{
> +	if (wdt_fd < 0)
> +		return;
> +
> +	if (write(wdt_fd, "V", 1) < 0)
> +		ERROR("WDT failed to write release: %s\n", strerror(errno));
> +
> +	if (close(wdt_fd) == -1)
> +		ERROR("WDT failed to close watchdog: %s\n", strerror(errno));
> +
> +	wdt_fd = -1;
> +}
> +
> +void watchdog_set_magicclose(bool val)
> +{
> +	wdt_magicclose = val;
> +}
> +
> +bool watchdog_get_magicclose(void)
> +{
> +	return wdt_magicclose;
> +}
> +
>   void watchdog_set_stopped(bool val)
>   {
> -	if (val)
> +	if (val) {
>   		uloop_timeout_cancel(&wdt_timeout);
> -	else
> +
> +		if (wdt_magicclose)
> +			watchdog_close();
> +	}
> +	else {
> +		watchdog_open(true);
>   		watchdog_timeout_cb(&wdt_timeout);
> +	}
>   }
>   
>   bool watchdog_get_stopped(void)
> @@ -98,26 +153,11 @@ char* watchdog_fd(void)
>   
>   void watchdog_init(int preinit)
>   {
> -	char *env = getenv("WDTFD");
> -
> -	if (wdt_fd >= 0)
> -		return;
> -
>   	wdt_timeout.cb = watchdog_timeout_cb;
> -	if (env) {
> -		DEBUG(2, "Watchdog handover: fd=%s\n", env);
> -		wdt_fd = atoi(env);
> -		unsetenv("WDTFD");
> -	} else {
> -		wdt_fd = open("/dev/watchdog", O_WRONLY);
> -	}
>   
> -	if (wdt_fd < 0)
> +	if (watchdog_open(!preinit) < 0)
>   		return;
>   
> -	if (!preinit)
> -		fcntl(wdt_fd, F_SETFD, fcntl(wdt_fd, F_GETFD) | FD_CLOEXEC);
> -
>   	LOG("- watchdog -\n");
>   	watchdog_timeout(30);
>   	watchdog_timeout_cb(&wdt_timeout);
> diff --git a/watchdog.h b/watchdog.h
> index 3c4a487..fd9aed2 100644
> --- a/watchdog.h
> +++ b/watchdog.h
> @@ -22,6 +22,8 @@ void watchdog_init(int preinit);
>   char* watchdog_fd(void);
>   int watchdog_timeout(int timeout);
>   int watchdog_frequency(int frequency);
> +void watchdog_set_magicclose(bool val);
> +bool watchdog_get_magicclose(void);
>   void watchdog_set_stopped(bool val);
>   bool watchdog_get_stopped(void);
>   void watchdog_set_cloexec(bool val);
> @@ -46,6 +48,14 @@ static inline int watchdog_frequency(int frequency)
>   	return 0;
>   }
>   
> +static inline void watchdog_set_magicclose(bool val)
> +{
> +}
> +
> +static inline void watchdog_get_magicclose(bool val)
> +{
> +}
> +
>   static inline void watchdog_set_stopped(bool val)
>   {
>   }