chiark / gitweb /
release 099
[elogind.git] / udev_rules.c
index 1483f8f4930d50b0d62d2c2a594b1a31f38353c2..edaaa71d12c7793c9716cb332ce5edaed41a2598 100644 (file)
@@ -458,30 +458,42 @@ found:
                        }
                        break;
                case SUBST_ATTR:
-                       if (attr == NULL) {
-                               dbg("missing attribute");
-                               break;
-                       } else {
-                               struct sysfs_device *dev_parent;
-                               const char *value;
+                       if (attr == NULL)
+                               err("missing file parameter for attr");
+                       else {
+                               const char *value = NULL;
+                               size_t size;
+
+                               /* first try the current device, other matches may have selected */
+                               if (udev->dev_parent != NULL && udev->dev_parent != udev->dev)
+                                       value = sysfs_attr_get_value(udev->dev_parent->devpath, attr);
+
+                               /* look at all devices along the chain of parents */
+                               if (value == NULL) {
+                                       struct sysfs_device *dev_parent = udev->dev;
+
+                                       do {
+                                               dbg("looking at '%s'", dev_parent->devpath);
+                                               value = sysfs_attr_get_value(dev_parent->devpath, attr);
+                                               if (value != NULL) {
+                                                       strlcpy(temp2, value, sizeof(temp2));
+                                                       break;
+                                               }
+                                               dev_parent = sysfs_device_get_parent(dev_parent);
+                                       } while (dev_parent != NULL);
+                               }
 
-                               dev_parent = udev->dev;
-                               do {
-                                       dbg("looking at '%s'", dev_parent->devpath);
-                                       value = sysfs_attr_get_value(dev_parent->devpath, attr);
-                                       if (value != NULL) {
-                                               strlcpy(temp2, value, sizeof(temp2));
-                                               break;
-                                       }
-                                       dev_parent = sysfs_device_get_parent(dev_parent);
-                               } while (dev_parent != NULL);
+                               if (value == NULL)
+                                       break;
 
-                               /* strip trailing whitespace of sysfs value */
-                               i = strlen(temp2);
-                               while (i > 0 && isspace(temp2[i-1]))
-                                       temp2[--i] = '\0';
+                               /* strip trailing whitespace and replace untrusted characters of sysfs value */
+                               size = strlcpy(temp2, value, sizeof(temp2));
+                               if (size >= sizeof(temp2))
+                                       size = sizeof(temp2)-1;
+                               while (size > 0 && isspace(temp2[size-1]))
+                                       temp2[--size] = '\0';
                                count = replace_untrusted_chars(temp2);
-                               if (count)
+                               if (count > 0)
                                        info("%i untrusted character(s) replaced" , count);
                                strlcat(string, temp2, maxsize);
                                dbg("substitute sysfs value '%s'", temp2);
@@ -693,7 +705,7 @@ static int match_rule(struct udevice *udev, struct udev_rule *rule)
                if (match_key("DRIVERS", rule, &rule->drivers, udev->dev_parent->driver))
                        goto try_parent;
 
-               /* check for matching sysfs attrubute pairs */
+               /* check for matching sysfs attribute pairs */
                for (i = 0; i < rule->attrs.count; i++) {
                        struct key_pair *pair = &rule->attrs.keys[i];