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 c76be21e8288a408484b58e70a3a3de76842043f..8afd68cc7666ddef1e12e2346ebe3db2e3ad5f58 100644 (file)
--- a/udev/lib/libudev-device.c
+++ b/udev/lib/libudev-device.c
@@ -41,11 +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;
@@ -176,7 +179,7 @@ static int device_read_db(struct udev_device *udev_device)
        return 0;
 }
 
-static int device_read_uevent_file(struct udev_device *udev_device)
+int udev_device_read_uevent_file(struct udev_device *udev_device)
 {
        char filename[UTIL_PATH_SIZE];
        FILE *f;
@@ -215,7 +218,7 @@ static int device_read_uevent_file(struct udev_device *udev_device)
 static void device_load_info(struct udev_device *device)
 {
        device->info_loaded = 1;
-       device_read_uevent_file(device);
+       udev_device_read_uevent_file(device);
        device_read_db(device);
 }
 
@@ -686,31 +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;
 }
 
 /**
@@ -737,6 +739,7 @@ struct udev_list_entry *udev_device_get_devlinks_list_entry(struct udev_device *
 
 void udev_device_cleanup_devlinks_list(struct udev_device *udev_device)
 {
+       udev_device->devlinks_uptodate = 0;
        udev_list_cleanup(udev_device->udev, &udev_device->devlinks_list);
 }
 
@@ -758,6 +761,21 @@ struct udev_list_entry *udev_device_get_properties_list_entry(struct udev_device
                return NULL;
        if (!udev_device->info_loaded)
                device_load_info(udev_device);
+       if (!udev_device->devlinks_uptodate) {
+               char symlinks[UTIL_PATH_SIZE];
+               struct udev_list_entry *list_entry;
+
+               udev_device->devlinks_uptodate = 1;
+               list_entry = udev_device_get_devlinks_list_entry(udev_device);
+               if (list_entry != NULL) {
+                       util_strlcpy(symlinks, udev_list_entry_get_name(list_entry), sizeof(symlinks));
+                       udev_list_entry_foreach(list_entry, udev_list_entry_get_next(list_entry)) {
+                               util_strlcat(symlinks, " ", sizeof(symlinks));
+                               util_strlcat(symlinks, udev_list_entry_get_name(list_entry), sizeof(symlinks));
+                       }
+                       udev_device_add_property(udev_device, "DEVLINKS", symlinks);
+               }
+       }
        return udev_list_get_entry(&udev_device->properties_list);
 }
 
@@ -767,11 +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;
 }
 
@@ -827,7 +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;
        }
 
@@ -921,6 +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;
 }
@@ -929,6 +949,8 @@ int udev_device_set_devnode(struct udev_device *udev_device, const char *devnode
 {
        free(udev_device->devnode);
        udev_device->devnode = strdup(devnode);
+       if (devnode == NULL)
+               return 0;
        if (udev_device->devnode == NULL)
                return -ENOMEM;
        udev_device_add_property(udev_device, "DEVNAME", udev_device->devnode);
@@ -937,18 +959,9 @@ int udev_device_set_devnode(struct udev_device *udev_device, const char *devnode
 
 int udev_device_add_devlink(struct udev_device *udev_device, const char *devlink)
 {
-       char symlinks[UTIL_PATH_SIZE];
-       struct udev_list_entry *list_entry;
-
+       udev_device->devlinks_uptodate = 0;
        if (udev_list_entry_add(udev_device->udev, &udev_device->devlinks_list, devlink, NULL, 1, 0) == NULL)
                return -ENOMEM;
-       list_entry =  udev_device_get_devlinks_list_entry(udev_device);
-       util_strlcpy(symlinks, udev_list_entry_get_name(list_entry), sizeof(symlinks));
-       udev_list_entry_foreach(list_entry, udev_list_entry_get_next(list_entry)) {
-               util_strlcat(symlinks, " ", sizeof(symlinks));
-               util_strlcat(symlinks, udev_list_entry_get_name(list_entry), sizeof(symlinks));
-       }
-       udev_device_add_property(udev_device, "DEVLINKS", symlinks);
        return 0;
 }
 
@@ -1013,6 +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;
 }