[PATCH] Backlight/LCD Class: Fix sysfs _store error handling

The backlight and LCD class _store functions currently accept values like "34
some random strings" without error.  This corrects them to return -EINVAL if
the value is not numeric with an optional byte of trailing whitespace.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 28 insertions, 22 deletions

diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c
index 334b1db1bd7c..27597c576eff 100644
--- a/drivers/video/backlight/backlight.c
+++ b/drivers/video/backlight/backlight.c
@@ -29,12 +29,15 @@ static ssize_t backlight_show_power(struct class_device *cdev, char *buf)
 
 static ssize_t backlight_store_power(struct class_device *cdev, const char *buf, size_t count)
 {
-        int rc = -ENXIO, power;
+        int rc = -ENXIO;
         char *endp;
         struct backlight_device *bd = to_backlight_device(cdev);
+        int power = simple_strtoul(buf, &endp, 0);
+        size_t size = endp - buf;
 
-        power = simple_strtoul(buf, &endp, 0);
-        if (*endp && !isspace(*endp))
+        if (*endp && isspace(*endp))
+                size++;
+        if (size != count)
                 return -EINVAL;
 
         down(&bd->sem);
@@ -65,12 +68,15 @@ static ssize_t backlight_show_brightness(struct class_device *cdev, char *buf)
 
 static ssize_t backlight_store_brightness(struct class_device *cdev, const char *buf, size_t count)
 {
-        int rc = -ENXIO, brightness;
+        int rc = -ENXIO;
         char *endp;
         struct backlight_device *bd = to_backlight_device(cdev);
+        int brightness = simple_strtoul(buf, &endp, 0);
+        size_t size = endp - buf;
 
-        brightness = simple_strtoul(buf, &endp, 0);
-        if (*endp && !isspace(*endp))
+        if (*endp && isspace(*endp))
+                size++;
+        if (size != count)
                 return -EINVAL;
 
         down(&bd->sem);
diff --git a/drivers/video/backlight/lcd.c b/drivers/video/backlight/lcd.c
index 86908a60c630..bc8ab005a3fb 100644
--- a/drivers/video/backlight/lcd.c
+++ b/drivers/video/backlight/lcd.c
@@ -31,12 +31,15 @@ static ssize_t lcd_show_power(struct class_device *cdev, char *buf)
 
 static ssize_t lcd_store_power(struct class_device *cdev, const char *buf, size_t count)
 {
-        int rc, power;
+        int rc = -ENXIO;
         char *endp;
         struct lcd_device *ld = to_lcd_device(cdev);
+        int power = simple_strtoul(buf, &endp, 0);
+        size_t size = endp - buf;
 
-        power = simple_strtoul(buf, &endp, 0);
-        if (*endp && !isspace(*endp))
+        if (*endp && isspace(*endp))
+                size++;
+        if (size != count)
                 return -EINVAL;
 
         down(&ld->sem);
@@ -44,8 +47,7 @@ static ssize_t lcd_store_power(struct class_device *cdev, const char *buf, size_
                 pr_debug("lcd: set power to %d\n", power);
                 ld->props->set_power(ld, power);
                 rc = count;
-        } else
-                rc = -ENXIO;
+        }
         up(&ld->sem);
 
         return rc;
@@ -53,14 +55,12 @@ static ssize_t lcd_store_power(struct class_device *cdev, const char *buf, size_
 
 static ssize_t lcd_show_contrast(struct class_device *cdev, char *buf)
 {
-        int rc;
+        int rc = -ENXIO;
         struct lcd_device *ld = to_lcd_device(cdev);
 
         down(&ld->sem);
         if (likely(ld->props && ld->props->get_contrast))
                 rc = sprintf(buf, "%d\n", ld->props->get_contrast(ld));
-        else
-                rc = -ENXIO;
         up(&ld->sem);
 
         return rc;
@@ -68,12 +68,15 @@ static ssize_t lcd_show_contrast(struct class_device *cdev, char *buf)
 
 static ssize_t lcd_store_contrast(struct class_device *cdev, const char *buf, size_t count)
 {
-        int rc, contrast;
+        int rc = -ENXIO;
         char *endp;
         struct lcd_device *ld = to_lcd_device(cdev);
+        int contrast = simple_strtoul(buf, &endp, 0);
+        size_t size = endp - buf;
 
-        contrast = simple_strtoul(buf, &endp, 0);
-        if (*endp && !isspace(*endp))
+        if (*endp && isspace(*endp))
+                size++;
+        if (size != count)
                 return -EINVAL;
 
         down(&ld->sem);
@@ -81,8 +84,7 @@ static ssize_t lcd_store_contrast(struct class_device *cdev, const char *buf, si
                 pr_debug("lcd: set contrast to %d\n", contrast);
                 ld->props->set_contrast(ld, contrast);
                 rc = count;
-        } else
-                rc = -ENXIO;
+        }
         up(&ld->sem);
 
         return rc;
@@ -90,14 +92,12 @@ static ssize_t lcd_store_contrast(struct class_device *cdev, const char *buf, si
 
 static ssize_t lcd_show_max_contrast(struct class_device *cdev, char *buf)
 {
-        int rc;
+        int rc = -ENXIO;
         struct lcd_device *ld = to_lcd_device(cdev);
 
         down(&ld->sem);
         if (likely(ld->props))
                 rc = sprintf(buf, "%d\n", ld->props->max_contrast);
-        else
-                rc = -ENXIO;
         up(&ld->sem);
 
         return rc;