store ENV{key}="value" exported keys in the database

Just like the IMPORT values are stored in the udev database the
exported keys are stored in the udev database. The database is also
imported on a remove event before the rules are matched. So it
is possible to do:
  ACTION=="add", KERNEL=="sda", ENV{MY_DEVICE}="1234", RUN+="/bin/logger add $devpath"
  ACTION=="remove", ENV{MY_DEVICE}=="1234", RUN+="/bin/logger remove $devpath"

Signed-off-by: Kay Sievers <kay.sievers@suse.de>

2 files changed, 10 insertions, 3 deletions

diff --git a/udev_event.c b/udev_event.c
index 3580ab937f..fae5a46597 100644
--- a/udev_event.c
+++ b/udev_event.c
@@ -91,15 +91,21 @@ int udev_process_event(struct udev_rules *rules, struct udevice *udev)
 			}
 			sysfs_close_class_device(class_dev);
 		} else if (strcmp(udev->action, "remove") == 0) {
+			struct name_entry *name_loop;
+
+			/* get data from db, remove db-entry, delete node */
 			dbg("node remove");
+			retval = udev_remove_device(udev);
+
+			/* restore stored persistent data */
+			list_for_each_entry(name_loop, &udev->env_list, node)
+				putenv(name_loop->name);
+
 			udev_rules_get_run(rules, udev, NULL, NULL);
 			if (udev->ignore_device) {
 				dbg("device event will be ignored");
 				return -1;
 			}
-
-			/* get name from db, remove db-entry, delete node */
-			retval = udev_remove_device(udev);
 		}
 
 		/* export name of device node or netif */
diff --git a/udev_rules.c b/udev_rules.c
index 647875d9a9..6c6aa0f091 100644
--- a/udev_rules.c
+++ b/udev_rules.c
@@ -859,6 +859,7 @@ try_parent:
 			const char *key_name = key_pair_name(rule, pair);
 			const char *value = key_val(rule, &pair->key);
 
+			name_list_key_add(&udev->env_list, key_name, value);
 			setenv(key_name, value, 1);
 			dbg("export ENV '%s=%s'", key_name, value);
 		}