first try "subsystem" link at a parent device, before guessing

diff --git a/udev_sysfs.c b/udev_sysfs.c
index 0e448894fef8f3c6edee1a0cd49cdd631f4d2893..7431dd6111692ec0afcd73ff2af56626a6b43747 100644 (file)
--- a/udev_sysfs.c
+++ b/udev_sysfs.c
@@ -197,8 +197,20 @@ struct sysfs_device *sysfs_device_get(const char *devpath)
 
        sysfs_device_set_values(dev, devpath_real, NULL, NULL);
 
-       /* get subsystem */
-       if (strncmp(dev->devpath, "/class/", 7) == 0) {
+       /* get subsystem name */
+       strlcpy(link_path, sysfs_path, sizeof(link_path));
+       strlcat(link_path, dev->devpath, sizeof(link_path));
+       strlcat(link_path, "/subsystem", sizeof(link_path));
+       len = readlink(link_path, link_target, sizeof(link_target));
+       if (len > 0) {
+               /* get subsystem from "subsystem" link */
+               link_target[len] = '\0';
+               dbg("subsystem link '%s' points to '%s'", link_path, link_target);
+               pos = strrchr(link_target, '/');
+               if (pos != NULL)
+                       strlcpy(dev->subsystem, &pos[1], sizeof(dev->subsystem));
+       } else if (strncmp(dev->devpath, "/class/", 7) == 0) {
+               /* get subsystem from class dir */
                strlcpy(dev->subsystem, &dev->devpath[7], sizeof(dev->subsystem));
                pos = strchr(dev->subsystem, '/');
                if (pos != NULL)
@@ -219,38 +231,26 @@ struct sysfs_device *sysfs_device_get(const char *devpath)
                        pos = strrchr(link_target, '/');
                        if (pos != NULL)
                                strlcpy(dev->subsystem, &pos[1], sizeof(dev->subsystem));
-               } else {
-                       /* get subsystem from "subsystem" link */
-                       strlcpy(link_path, sysfs_path, sizeof(link_path));
-                       strlcat(link_path, dev->devpath, sizeof(link_path));
-                       strlcat(link_path, "/subsystem", sizeof(link_path));
-                       len = readlink(link_path, link_target, sizeof(link_target));
-                       if (len > 0) {
-                               link_target[len] = '\0';
-                               dbg("subsystem link '%s' points to '%s'", link_path, link_target);
-                               pos = strrchr(link_target, '/');
-                               if (pos != NULL)
-                                       strlcpy(dev->subsystem, &pos[1], sizeof(dev->subsystem));
-                       }
-               }
-               /* get driver name */
-               strlcpy(link_path, sysfs_path, sizeof(link_path));
-               strlcat(link_path, dev->devpath, sizeof(link_path));
-               strlcat(link_path, "/driver", sizeof(link_path));
-               len = readlink(link_path, link_target, sizeof(link_target));
-               if (len > 0) {
-                       link_target[len] = '\0';
-                       dbg("driver link '%s' points to '%s'", link_path, link_target);
-                       pos = strrchr(link_target, '/');
-                       if (pos != NULL)
-                               strlcpy(dev->driver, &pos[1], sizeof(dev->driver));
                }
-       } else if (strncmp(dev->devpath, "/bus/", 5) == 0 && strstr(dev->devpath, "/drivers/")) {
+       } else if (strstr(dev->devpath, "/drivers/") != NULL) {
                strlcpy(dev->subsystem, "drivers", sizeof(dev->subsystem));
        } else if (strncmp(dev->devpath, "/module/", 8) == 0) {
                strlcpy(dev->subsystem, "module", sizeof(dev->subsystem));
        }
 
+       /* get driver name */
+       strlcpy(link_path, sysfs_path, sizeof(link_path));
+       strlcat(link_path, dev->devpath, sizeof(link_path));
+       strlcat(link_path, "/driver", sizeof(link_path));
+       len = readlink(link_path, link_target, sizeof(link_target));
+       if (len > 0) {
+               link_target[len] = '\0';
+               dbg("driver link '%s' points to '%s'", link_path, link_target);
+               pos = strrchr(link_target, '/');
+               if (pos != NULL)
+                       strlcpy(dev->driver, &pos[1], sizeof(dev->driver));
+       }
+
        dbg("add to cache 'devpath=%s', subsystem='%s', driver='%s'", dev->devpath, dev->subsystem, dev->driver);
        list_add(&dev->node, &dev_list);
 
@@ -270,6 +270,7 @@ struct sysfs_device *sysfs_device_get_parent(struct sysfs_device *dev)
 
        /* requesting a parent is only valid for devices */
        if ((strncmp(dev->devpath, "/devices/", 9) != 0) &&
+           (strncmp(dev->devpath, "/subsystem/", 11) != 0) &&
            (strncmp(dev->devpath, "/class/", 7) != 0) &&
            (strncmp(dev->devpath, "/block/", 7) != 0))
                return NULL;
@@ -289,10 +290,13 @@ struct sysfs_device *sysfs_device_get_parent(struct sysfs_device *dev)
                return NULL;
        }
 
-       /* at the top level of class/block we want to follow the "device" link */
-       if (strcmp(parent_devpath, "/block") == 0) {
-               dbg("/block top level, look for device link");
-               goto device_link;
+       /* at the subsystems top level we want to follow the old-style "device" link */
+       if (strncmp(parent_devpath, "/subsystem", 10) == 0) {
+               pos = strrchr(parent_devpath, '/');
+               if (pos == &parent_devpath[10] || pos == parent_devpath || strcmp(pos, "/devices") == 0) {
+                       dbg("/subsystem top level, look for device link");
+                       goto device_link;
+               }
        }
        if (strncmp(parent_devpath, "/class", 6) == 0) {
                pos = strrchr(parent_devpath, '/');
@@ -301,6 +305,11 @@ struct sysfs_device *sysfs_device_get_parent(struct sysfs_device *dev)
                        goto device_link;
                }
        }
+       if (strcmp(parent_devpath, "/block") == 0) {
+               dbg("/block top level, look for device link");
+               goto device_link;
+       }
+
        /* get parent and remember it */
        dev->parent = sysfs_device_get(parent_devpath);
        return dev->parent;