Re: RUN rules to enable/disable printer queues

[Kay Sievers <kay.sievers@vrfy.org>]

[-- Attachment #1: Type: text/plain, Size: 1366 bytes --]

On Fri, Aug 26, 2005 at 01:46:25PM +0200, Kay Sievers wrote:
> On Thu, Aug 25, 2005 at 08:06:05PM -0700, Zack Weinberg wrote:
> > Kay Sievers said:
> > 
> > > Use two rules, one for ACTION="add" and one for "remove" if you want to
> > > name the device at the same time. The SYMLINK key prevents rule to be
> > > catched by a "remove" cause it is only valid to _create_ a link - same
> > > for NAME, OWNER, GROUP, MODE.
> > 
> > Okay, so now I have
> > 
> >     BUS=="usb", SYSFS{product}=="Lexmark Optra E310", \
> >     SYSFS{serial}=="0101137", ACTION=="remove", \
> >         RUN+="/etc/udev/scripts/lpqueue.sh"
> 
> > ... and it still doesn't work: lpqueue.sh is invoked only on add, not remove.
> 
> The device is removed, so sysfs is obviously not available.

The attached patch should make it possible to store a variable in the
environment and at the same time in the udev database. This variable is
also available at "remove":
  ACTION=="add", KERNEL=="sda", ENV{MY_DEVICE}="1234", RUN+="/bin/logger add $devpath"
  ACTION=="remove", ENV{MY_DEVICE}=="1234", RUN+="/bin/logger remove $devpath"

This way it is also possible to export "remove" values, that are used in a RUN
key:
  ACTION=="add", KERNEL=="sda", ENV{MY_REMOVE}="/bin/logger remove $devpath", RUN+="/bin/logger add $devpath"
  ACTION=="remove", ENV{MY_REMOVE}!="", RUN+="$env{MY_REMOVE}"

Kay

[-- Attachment #2: udev-env-at-remove-01.patch --]
[-- Type: text/plain, Size: 1183 bytes --]

diff --git a/udev_event.c b/udev_event.c
--- a/udev_event.c
+++ b/udev_event.c
@@ -91,15 +91,21 @@ int udev_process_event(struct udev_rules
 			}
 			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
--- 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);
 		}