X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Flibudev%2Flibudev-device.c;h=6bb2e41510ab97d36eac96a0d326724905792165;hp=9fe3d633d4dbaa5ccedbabe7bf96a4de53cf0a3b;hb=53726349e1d7a85bdf572ce81f122e66e438c6ec;hpb=d5a89d7dc17a5ba5cf4fc71f82963c5c94a31c3d

diff --git a/src/libudev/libudev-device.c b/src/libudev/libudev-device.c
index 9fe3d633d..6bb2e4151 100644
--- a/src/libudev/libudev-device.c
+++ b/src/libudev/libudev-device.c
@@ -1381,8 +1381,6 @@ _public_ const char *udev_device_get_sysattr_value(struct udev_device *udev_devi
         }
 
         if (S_ISLNK(statbuf.st_mode)) {
-                struct udev_device *dev;
-
                 /*
                  * Some core links return only the last element of the target path,
                  * these are just values, the paths should not be exposed.
@@ -1398,17 +1396,6 @@ _public_ const char *udev_device_get_sysattr_value(struct udev_device *udev_devi
                         goto out;
                 }
 
-                /* resolve custom link to a device and return its syspath */
-                if (!streq(sysattr, "device")) {
-                        strscpyl(path, sizeof(path), udev_device->syspath, "/", sysattr, NULL);
-                        dev = udev_device_new_from_syspath(udev_device->udev, path);
-                        if (dev != NULL) {
-                                list_entry = udev_list_entry_add(&udev_device->sysattr_value_list, sysattr,
-                                                                 udev_device_get_syspath(dev));
-                                val = udev_list_entry_get_value(list_entry);
-                                udev_device_unref(dev);
-                        }
-                }
                 goto out;
         }
 
@@ -1440,6 +1427,91 @@ out:
         return val;
 }
 
+/**
+ * udev_device_set_sysattr_value:
+ * @udev_device: udev device
+ * @sysattr: attribute name
+ * @value: new value to be set
+ *
+ * Update the contents of the sys attribute and the cached value of the device.
+ *
+ * Returns: Negative error code on failure or 0 on success.
+ **/
+_public_ int udev_device_set_sysattr_value(struct udev_device *udev_device, const char *sysattr, char *value)
+{
+        struct udev_device *dev;
+        char path[UTIL_PATH_SIZE];
+        struct stat statbuf;
+        int fd;
+        ssize_t size, value_len;
+        int ret = 0;
+
+        if (udev_device == NULL)
+                return -EINVAL;
+        dev = udev_device;
+        if (sysattr == NULL)
+                return -EINVAL;
+        if (value == NULL)
+                value_len = 0;
+        else
+                value_len = strlen(value);
+
+        strscpyl(path, sizeof(path), udev_device_get_syspath(dev), "/", sysattr, NULL);
+        if (lstat(path, &statbuf) != 0) {
+                udev_list_entry_add(&dev->sysattr_value_list, sysattr, NULL);
+                ret = -ENXIO;
+                goto out;
+        }
+
+        if (S_ISLNK(statbuf.st_mode)) {
+                ret = -EINVAL;
+                goto out;
+        }
+
+        /* skip directories */
+        if (S_ISDIR(statbuf.st_mode)) {
+                ret = -EISDIR;
+                goto out;
+        }
+
+        /* skip non-readable files */
+        if ((statbuf.st_mode & S_IRUSR) == 0) {
+                ret = -EACCES;
+                goto out;
+        }
+
+        /* Value is limited to 4k */
+        if (value_len > 4096) {
+                ret = -EINVAL;
+                goto out;
+        }
+        util_remove_trailing_chars(value, '\n');
+
+        /* write attribute value */
+        fd = open(path, O_WRONLY|O_CLOEXEC);
+        if (fd < 0) {
+                ret = -errno;
+                goto out;
+        }
+        size = write(fd, value, value_len);
+        close(fd);
+        if (size < 0) {
+                ret = -errno;
+                goto out;
+        }
+        if (size < value_len) {
+                ret = -EIO;
+                goto out;
+        }
+
+        /* wrote a valid value, store it in cache and return it */
+        udev_list_entry_add(&dev->sysattr_value_list, sysattr, value);
+out:
+        if (dev != udev_device)
+                udev_device_unref(dev);
+        return ret;
+}
+
 static int udev_device_sysattr_list_read(struct udev_device *udev_device)
 {
         struct dirent *dent;