watchdog: Use sysfs_emit() and sysfs_emit_at() in "show" functions

Convert sprintf() in sysfs "show" functions to sysfs_emit() and
sysfs_emit_at() in order to check for buffer overruns in sysfs outputs.

Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20210511061812.480172-1-juergh@canonical.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

drivers/watchdog/aspeed_wdt.c

@@ -175,7 +175,7 @@ static ssize_t access_cs0_show(struct device *dev,
 	struct aspeed_wdt *wdt = dev_get_drvdata(dev);
 	u32 status = readl(wdt->base + WDT_TIMEOUT_STATUS);
 
-	return sprintf(buf, "%u\n",
+	return sysfs_emit(buf, "%u\n",
 			  !(status & WDT_TIMEOUT_STATUS_BOOT_SECONDARY));
 }
 

drivers/watchdog/watchdog_dev.c

@@ -451,7 +451,8 @@ static ssize_t nowayout_show(struct device *dev, struct device_attribute *attr,
 {
 	struct watchdog_device *wdd = dev_get_drvdata(dev);
 
-	return sprintf(buf, "%d\n", !!test_bit(WDOG_NO_WAY_OUT, &wdd->status));
+	return sysfs_emit(buf, "%d\n", !!test_bit(WDOG_NO_WAY_OUT,
+						  &wdd->status));
 }
 
 static ssize_t nowayout_store(struct device *dev, struct device_attribute *attr,
@@ -485,7 +486,7 @@ static ssize_t status_show(struct device *dev, struct device_attribute *attr,
 	status = watchdog_get_status(wdd);
 	mutex_unlock(&wd_data->lock);
 
-	return sprintf(buf, "0x%x\n", status);
+	return sysfs_emit(buf, "0x%x\n", status);
 }
 static DEVICE_ATTR_RO(status);
 
@@ -494,7 +495,7 @@ static ssize_t bootstatus_show(struct device *dev,
 {
 	struct watchdog_device *wdd = dev_get_drvdata(dev);
 
-	return sprintf(buf, "%u\n", wdd->bootstatus);
+	return sysfs_emit(buf, "%u\n", wdd->bootstatus);
 }
 static DEVICE_ATTR_RO(bootstatus);
 
@@ -510,7 +511,7 @@ static ssize_t timeleft_show(struct device *dev, struct device_attribute *attr,
 	status = watchdog_get_timeleft(wdd, &val);
 	mutex_unlock(&wd_data->lock);
 	if (!status)
-		status = sprintf(buf, "%u\n", val);
+		status = sysfs_emit(buf, "%u\n", val);
 
 	return status;
 }
@@ -521,7 +522,7 @@ static ssize_t timeout_show(struct device *dev, struct device_attribute *attr,
 {
 	struct watchdog_device *wdd = dev_get_drvdata(dev);
 
-	return sprintf(buf, "%u\n", wdd->timeout);
+	return sysfs_emit(buf, "%u\n", wdd->timeout);
 }
 static DEVICE_ATTR_RO(timeout);
 
@@ -548,7 +549,7 @@ static ssize_t pretimeout_show(struct device *dev,
 {
 	struct watchdog_device *wdd = dev_get_drvdata(dev);
 
-	return sprintf(buf, "%u\n", wdd->pretimeout);
+	return sysfs_emit(buf, "%u\n", wdd->pretimeout);
 }
 static DEVICE_ATTR_RO(pretimeout);
 
@@ -557,7 +558,7 @@ static ssize_t identity_show(struct device *dev, struct device_attribute *attr,
 {
 	struct watchdog_device *wdd = dev_get_drvdata(dev);
 
-	return sprintf(buf, "%s\n", wdd->info->identity);
+	return sysfs_emit(buf, "%s\n", wdd->info->identity);
 }
 static DEVICE_ATTR_RO(identity);
 
@@ -567,9 +568,9 @@ static ssize_t state_show(struct device *dev, struct device_attribute *attr,
 	struct watchdog_device *wdd = dev_get_drvdata(dev);
 
 	if (watchdog_active(wdd))
-		return sprintf(buf, "active\n");
+		return sysfs_emit(buf, "active\n");
 
-	return sprintf(buf, "inactive\n");
+	return sysfs_emit(buf, "inactive\n");
 }
 static DEVICE_ATTR_RO(state);
 

drivers/watchdog/watchdog_pretimeout.c

@@ -55,7 +55,7 @@ int watchdog_pretimeout_available_governors_get(char *buf)
 	mutex_lock(&governor_lock);
 
 	list_for_each_entry(priv, &governor_list, entry)
-		count += sprintf(buf + count, "%s\n", priv->gov->name);
+		count += sysfs_emit_at(buf, count, "%s\n", priv->gov->name);
 
 	mutex_unlock(&governor_lock);
 
@@ -68,7 +68,7 @@ int watchdog_pretimeout_governor_get(struct watchdog_device *wdd, char *buf)
 
 	spin_lock_irq(&pretimeout_lock);
 	if (wdd->gov)
-		count = sprintf(buf, "%s\n", wdd->gov->name);
+		count = sysfs_emit(buf, "%s\n", wdd->gov->name);
 	spin_unlock_irq(&pretimeout_lock);
 
 	return count;

drivers/watchdog/ziirave_wdt.c

@@ -445,7 +445,8 @@ static ssize_t ziirave_wdt_sysfs_show_firm(struct device *dev,
 	if (ret)
 		return ret;
 
-	ret = sprintf(buf, ZIIRAVE_FW_VERSION_FMT, w_priv->firmware_rev.major,
+	ret = sysfs_emit(buf, ZIIRAVE_FW_VERSION_FMT,
+			 w_priv->firmware_rev.major,
 			 w_priv->firmware_rev.minor);
 
 	mutex_unlock(&w_priv->sysfs_mutex);
@@ -468,7 +469,8 @@ static ssize_t ziirave_wdt_sysfs_show_boot(struct device *dev,
 	if (ret)
 		return ret;
 
-	ret = sprintf(buf, ZIIRAVE_BL_VERSION_FMT, w_priv->bootloader_rev.major,
+	ret = sysfs_emit(buf, ZIIRAVE_BL_VERSION_FMT,
+			 w_priv->bootloader_rev.major,
 			 w_priv->bootloader_rev.minor);
 
 	mutex_unlock(&w_priv->sysfs_mutex);
@@ -491,7 +493,7 @@ static ssize_t ziirave_wdt_sysfs_show_reason(struct device *dev,
 	if (ret)
 		return ret;
 
-	ret = sprintf(buf, "%s", ziirave_reasons[w_priv->reset_reason]);
+	ret = sysfs_emit(buf, "%s", ziirave_reasons[w_priv->reset_reason]);
 
 	mutex_unlock(&w_priv->sysfs_mutex);