libudev: udev_device_get_sysattr_list_entry() update

[elogind.git] / libudev / libudev-device.c

diff --git a/libudev/libudev-device.c b/libudev/libudev-device.c
index 16bee19dff4cca9463aab0b24e44fd593d1d12e0..8b8507c3a415dc32c5c79a06fd4805e6aa6ce887 100644 (file)
--- a/libudev/libudev-device.c
+++ b/libudev/libudev-device.c
@@ -60,6 +60,7 @@ struct udev_device {
        size_t monitor_buf_len;
        struct udev_list_node devlinks_list;
        struct udev_list_node properties_list;
+       struct udev_list_node sysattr_value_list;
        struct udev_list_node sysattr_list;
        struct udev_list_node tags_list;
        unsigned long long int seqnum;
@@ -83,6 +84,7 @@ struct udev_device {
        bool db_loaded;
        bool uevent_loaded;
        bool is_initialized;
+       bool sysattr_list_read;
 };
 
 struct udev_list_entry *udev_device_add_property(struct udev_device *udev_device, const char *key, const char *value)
@@ -360,6 +362,7 @@ struct udev_device *udev_device_new(struct udev *udev)
        udev_device->udev = udev;
        udev_list_init(&udev_device->devlinks_list);
        udev_list_init(&udev_device->properties_list);
+       udev_list_init(&udev_device->sysattr_value_list);
        udev_list_init(&udev_device->sysattr_list);
        udev_list_init(&udev_device->tags_list);
        udev_device->event_timeout = -1;
@@ -784,6 +787,7 @@ void udev_device_unref(struct udev_device *udev_device)
        free(udev_device->devtype);
        udev_list_cleanup_entries(udev_device->udev, &udev_device->devlinks_list);
        udev_list_cleanup_entries(udev_device->udev, &udev_device->properties_list);
+       udev_list_cleanup_entries(udev_device->udev, &udev_device->sysattr_value_list);
        udev_list_cleanup_entries(udev_device->udev, &udev_device->sysattr_list);
        udev_list_cleanup_entries(udev_device->udev, &udev_device->tags_list);
        free(udev_device->action);
@@ -1162,7 +1166,7 @@ const char *udev_device_get_sysattr_value(struct udev_device *udev_device, const
                return NULL;
 
        /* look for possibly already cached result */
-       udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_device->sysattr_list)) {
+       udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_device->sysattr_value_list)) {
                if (strcmp(udev_list_entry_get_name(list_entry), sysattr) == 0) {
                        dbg(udev_device->udev, "got '%s' (%s) from cache\n",
                            sysattr, udev_list_entry_get_value(list_entry));
@@ -1173,7 +1177,7 @@ const char *udev_device_get_sysattr_value(struct udev_device *udev_device, const
        util_strscpyl(path, sizeof(path), udev_device_get_syspath(udev_device), "/", sysattr, NULL);
        if (lstat(path, &statbuf) != 0) {
                dbg(udev_device->udev, "no attribute '%s', keep negative entry\n", path);
-               udev_list_entry_add(udev_device->udev, &udev_device->sysattr_list, sysattr, NULL, 0, 0);
+               udev_list_entry_add(udev_device->udev, &udev_device->sysattr_value_list, sysattr, NULL, 0, 0);
                goto out;
        }
 
@@ -1197,7 +1201,7 @@ const char *udev_device_get_sysattr_value(struct udev_device *udev_device, const
                if (pos != NULL) {
                        pos = &pos[1];
                        dbg(udev_device->udev, "cache '%s' with link value '%s'\n", sysattr, pos);
-                       list_entry = udev_list_entry_add(udev_device->udev, &udev_device->sysattr_list, sysattr, pos, 0, 0);
+                       list_entry = udev_list_entry_add(udev_device->udev, &udev_device->sysattr_value_list, sysattr, pos, 0, 0);
                        val = udev_list_entry_get_value(list_entry);
                }
 
@@ -1229,12 +1233,78 @@ const char *udev_device_get_sysattr_value(struct udev_device *udev_device, const
        value[size] = '\0';
        util_remove_trailing_chars(value, '\n');
        dbg(udev_device->udev, "'%s' has attribute value '%s'\n", path, value);
-       list_entry = udev_list_entry_add(udev_device->udev, &udev_device->sysattr_list, sysattr, value, 0, 0);
+       list_entry = udev_list_entry_add(udev_device->udev, &udev_device->sysattr_value_list, sysattr, value, 0, 0);
        val = udev_list_entry_get_value(list_entry);
 out:
        return val;
 }
 
+static int udev_device_sysattr_list_read(struct udev_device *udev_device)
+{
+       struct dirent *dent;
+       DIR *dir;
+       int num = 0;
+
+       if (udev_device == NULL)
+               return -1;
+       if (udev_device->sysattr_list_read)
+               return 0;
+
+       dir = opendir(udev_device_get_syspath(udev_device));
+       if (!dir) {
+               dbg(udev_device->udev, "sysfs dir '%s' can not be opened\n",
+                               udev_device_get_syspath(udev_device));
+               return -1;
+       }
+
+       for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
+               char path[UTIL_PATH_SIZE];
+               struct stat statbuf;
+
+               /* only handle symlinks and regular files */
+               if (dent->d_type != DT_LNK && dent->d_type != DT_REG)
+                       continue;
+
+               util_strscpyl(path, sizeof(path), udev_device_get_syspath(udev_device), "/", dent->d_name, NULL);
+               if (lstat(path, &statbuf) != 0)
+                       continue;
+               if ((statbuf.st_mode & S_IRUSR) == 0)
+                       continue;
+
+               udev_list_entry_add(udev_device->udev, &udev_device->sysattr_list,
+                                   dent->d_name, NULL, 0, 0);
+               num++;
+       }
+
+       closedir(dir);
+       dbg(udev_device->udev, "found %d sysattrs for '%s'\n", num, udev_device_get_syspath(udev_device));
+       udev_device->sysattr_list_read = true;
+
+       return num;
+}
+
+/**
+ * udev_device_get_sysattr_list_entry:
+ * @udev_device: udev device
+ *
+ * Retrieve the list of available sysattrs, with value being empty;
+ * This just return all available sysfs attributes for a particular
+ * device without reading their values.
+ *
+ * Returns: the first entry of the property list
+ **/
+struct udev_list_entry *udev_device_get_sysattr_list_entry(struct udev_device *udev_device)
+{
+       if (!udev_device->sysattr_list_read) {
+               int ret;
+               ret = udev_device_sysattr_list_read(udev_device);
+               if (0 > ret)
+                       return NULL;
+       }
+
+       return udev_list_get_entry(&udev_device->sysattr_list);
+}
+
 int udev_device_set_syspath(struct udev_device *udev_device, const char *syspath)
 {
        const char *pos;