libudev: device - lookup "subsystem" and "driver" only once

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

diff --git a/udev/lib/libudev-device.c b/udev/lib/libudev-device.c
index 5b90af68b89026a4cfdb362f2de5b6b852ea727d..8afd68cc7666ddef1e12e2346ebe3db2e3ad5f58 100644 (file)
--- a/udev/lib/libudev-device.c
+++ b/udev/lib/libudev-device.c
@@ -41,12 +41,14 @@ struct udev_device {
        const char *sysnum;
        char *devnode;
        char *subsystem;
+       int subsystem_set;
        struct udev_list_node devlinks_list;
        int devlinks_uptodate;
        struct udev_list_node properties_list;
        char *envp[128];
        int envp_uptodate;
        char *driver;
+       int driver_set;
        dev_t devnum;
        char *action;
        int event_timeout;
@@ -687,31 +689,30 @@ const char *udev_device_get_subsystem(struct udev_device *udev_device)
 
        if (udev_device == NULL)
                return NULL;
-       if (udev_device->subsystem != NULL)
-               return udev_device->subsystem;
-
-       /* read "subsytem" link */
-       if (util_get_sys_subsystem(udev_device->udev, udev_device->syspath, subsystem, sizeof(subsystem)) > 0) {
-               udev_device->subsystem = strdup(subsystem);
-               return udev_device->subsystem;
-       }
-
-       /* implicit names */
-       if (strncmp(udev_device->devpath, "/module/", 8) == 0) {
-               udev_device->subsystem = strdup("module");
-               return udev_device->subsystem;
-       }
-       if (strstr(udev_device->devpath, "/drivers/") != NULL) {
-               udev_device->subsystem = strdup("drivers");
-               return udev_device->subsystem;
-       }
-       if (strncmp(udev_device->devpath, "/subsystem/", 11) == 0 ||
-           strncmp(udev_device->devpath, "/class/", 7) == 0 ||
-           strncmp(udev_device->devpath, "/bus/", 5) == 0) {
-               udev_device->subsystem = strdup("subsystem");
-               return udev_device->subsystem;
+       if (!udev_device->subsystem_set) {
+               udev_device->subsystem_set = 1;
+               /* read "subsytem" link */
+               if (util_get_sys_subsystem(udev_device->udev, udev_device->syspath, subsystem, sizeof(subsystem)) > 0) {
+                       udev_device_set_subsystem(udev_device, subsystem);
+                       return udev_device->subsystem;
+               }
+               /* implicit names */
+               if (strncmp(udev_device->devpath, "/module/", 8) == 0) {
+                       udev_device_set_subsystem(udev_device, "module");
+                       return udev_device->subsystem;
+               }
+               if (strstr(udev_device->devpath, "/drivers/") != NULL) {
+                       udev_device_set_subsystem(udev_device, "drivers");
+                       return udev_device->subsystem;
+               }
+               if (strncmp(udev_device->devpath, "/subsystem/", 11) == 0 ||
+                   strncmp(udev_device->devpath, "/class/", 7) == 0 ||
+                   strncmp(udev_device->devpath, "/bus/", 5) == 0) {
+                       udev_device_set_subsystem(udev_device, "subsystem");
+                       return udev_device->subsystem;
+               }
        }
-       return NULL;
+       return udev_device->subsystem;
 }
 
 /**
@@ -784,11 +785,11 @@ const char *udev_device_get_driver(struct udev_device *udev_device)
 
        if (udev_device == NULL)
                return NULL;
-       if (udev_device->driver != NULL)
-               return udev_device->driver;
-       if (util_get_sys_driver(udev_device->udev, udev_device->syspath, driver, sizeof(driver)) < 2)
-               return NULL;
-       udev_device->driver = strdup(driver);
+       if (!udev_device->driver_set) {
+               udev_device->driver_set = 1;
+               if (util_get_sys_driver(udev_device->udev, udev_device->syspath, driver, sizeof(driver)) > 0)
+                       udev_device->driver = strdup(driver);
+       }
        return udev_device->driver;
 }
 
@@ -844,7 +845,8 @@ const char *udev_device_get_attr_value(struct udev_device *udev_device, const ch
        util_strlcat(path, attr, sizeof(path));
 
        if (lstat(path, &statbuf) != 0) {
-               info(udev_device->udev, "stat '%s' failed: %m\n", path);
+               info(udev_device->udev, "no attribute '%s', keep negative entry\n", path);
+               udev_list_entry_add(udev_device->udev, &udev_device->attr_list, attr, NULL, 0, 0);
                goto out;
        }
 
@@ -938,6 +940,7 @@ int udev_device_set_subsystem(struct udev_device *udev_device, const char *subsy
        udev_device->subsystem = strdup(subsystem);
        if (udev_device->subsystem == NULL)
                return -ENOMEM;
+       udev_device->subsystem_set = 1;
        udev_device_add_property(udev_device, "SUBSYSTEM", udev_device->subsystem);
        return 0;
 }
@@ -1023,6 +1026,7 @@ int udev_device_set_driver(struct udev_device *udev_device, const char *driver)
        udev_device->driver = strdup(driver);
        if (udev_device->driver == NULL)
                return -ENOMEM;
+       udev_device->driver_set = 1;
        return 0;
 }