[systemd-devel] [RFC][PATCH] Escape unit name from udev

[Kay Sievers]

On Mon, May 6, 2013 at 11:12 PM, Lennart Poettering
<lennart at poettering.net> wrote:
> On Tue, 23.04.13 13:34, MUNEDA Takahiro (muneda.takahiro at jp.fujitsu.com) wrote:
>
>> This patch escapes a unit name which was derived from udev.
>>
>> Please imagine following udev rule.
>>
>>   ACTION=="online|offline", TAG+="systemd", ENV{SYSTEMD_WANTS}="muneda@%p.service"
>>   ACTION=="online|offline", TAG+="systemd", ENV{SYSTEMD_WANTS}="muneda@%r.service"
>>   ACTION=="online|offline", TAG+="systemd", ENV{SYSTEMD_WANTS}="muneda@%S.service"
>>
>> When unit name is derived from udev via
>> udev_device_get_property_value(), the name may contains '/' if
>> ENV{SYSTEMD_WANTS} has the udev options $devpath(%p), $root(%r), or
>> $sys(%S).  However, '/' is a invalid char for unit name so processing
>> of this rule fails as Invalid argument with following message.
>>
>> Apr 22 13:21:37 localhost systemd[1]: Failed to load device unit: Invalid argument
>> Apr 22 13:21:37 localhost systemd[1]: Failed to process udev device event: Invalid argument
>>
>> This patch escapes those invalid chars in a unit name.
>> Tested with 202, and confirmed to apply cleanly on top of commit 195f8e36.
>
> The patch looks OK I guess. I merged it now. I am not entirely sure
> though that using the devpath as instance name is actually the best
> choice... Kay?

Some devices can move around during runtime, the device number (dev_t,
ifindex) or the "<subsytem>:<devname>" is usually the better choice. A
bit like this:
  http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/base/core.c#n1918

Kay