Does RUN work with "remove" events?

Does RUN work with "remove" events?

[Moshe Yudkowsky]

I've written a udev rule to add a UMS flash drive with device name /dev/ums:

SYSFS{product}="Flash Disk", NAME="ums", RUN+="/etc/hotplug/usb/ums"

I've used "product" in the hope that the rule will be more general, and 
I won't have to change it for each new USB flash drive.

I selected "Flash Drive based on the following stansa that I saw in 
udevinfo:

>   looking at the device chain at '/sys/devices/pci0000:00/0000:00:10.3/usb4/4-2':
>     BUS="usb"
>     ID="4-2"
>     DRIVER="usb"
>     SYSFS{bConfigurationValue}="1"
>     SYSFS{bDeviceClass}="00"
>     SYSFS{bDeviceProtocol}="00"
>     SYSFS{bDeviceSubClass}="00"
>     SYSFS{bMaxPower}="200mA"
>     SYSFS{bNumConfigurations}="1"
>     SYSFS{bNumInterfaces}=" 1"
>     SYSFS{bcdDevice}="0200"
>     SYSFS{bmAttributes}="80"
>     SYSFS{configuration}=""
>     SYSFS{devnum}="18"
>     SYSFS{idProduct}="2168"
>     SYSFS{idVendor}="0ea0"
>     SYSFS{manufacturer}="USB     "
>     SYSFS{maxchild}="0"
>     SYSFS{product}="Flash Disk      "
>     SYSFS{serial}="255A07F4403C2C06"
>     SYSFS{speed}="480"
>     SYSFS{version}=" 2.00"
> 


When I plug  in the flash drive, I get the expected result: the RUN 
script runs (as well as the scsi_generic script), and I get a /dev/ums 
device.

> run_program: '/etc/hotplug/usb/ums' 'block'

and

> run_program '/etc/hotplug/usb/ums' 'scsi_generic'

as well because I used RUN+= instead of RUN=.

The problem is on remove. The file /dev/hotplug.log shows that I in fact 
do get a hotplug event of "remove":

> HOTPLUG_TIME='Wed Nov 30 15:40:04 CST 2005'
> SUBSYSTEM=usb
> OLDPWD=/
> DEVPATH=/devices/pci0000:00/0000:00:10.3/usb4/4-2
> ACTION=remove
> UDEV_LOG=3
> UDEVD_EVENT=1
> PHYSDEVBUS=usb
> SEQNUM\x1255

and I can see from udevmonitor:

> UDEV  [1133386804.167444] remove@/devices/pci0000:00/0000:00:10.3/usb4/4-2

and I get events from udev such as

> udev_event_run: seq 1277 forked, pid [4221], 'remove' 'scsi_generic', 0 seconds old


But the script in RUN never runs -- and I can see this in the udev 
output log, which I won't attach here.

So, here's the questions:

(a) Is udev supposed to work this way?
(b) If it is supposed to work this way, what's the recommended method to 
get RUN to work on ACTIONs of "remove"?
(c) If it isn't supposed to work this way, does anyone have any 
debugging suggestions or ideas of what to try next?

Regards,
  Moshe Yudkowsky
  (work) http://www.Disaggregate.com
  (book) http://www.PebbleAndAvalanche.com




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Re: Does RUN work with "remove" events?

[Kay Sievers]

On Wed, Nov 30, 2005 at 04:14:45PM -0600, Moshe Yudkowsky wrote:
> I've written a udev rule to add a UMS flash drive with device name /dev/ums:
> 
> SYSFS{product}="Flash Disk", NAME="ums", RUN+="/etc/hotplug/usb/ums"

Sysfs values are not readable at remove, cause the device directory is
already gone. You need to match against properties which you can see in
udevmonitor --env or you need to store a custom key with ENV{key}="value"
in the database, which is imported on remove.

Kay


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Re: Does RUN work with "remove" events?

[Moshe Yudkowsky]

Kay Sievers wrote:

 > On Wed, Nov 30, 2005 at 04:14:45PM -0600, Moshe Yudkowsky wrote:
 >
 >> I've written a udev rule to add a UMS flash drive with device name 
/dev/ums:
 >>
 >> SYSFS{product}="Flash Disk", NAME="ums", RUN+="/etc/hotplug/usb/ums"
 >
 >
 >
 > Sysfs values are not readable at remove, cause the device directory is
 > already gone. You need to match against properties which you can see in
 > udevmonitor --env or you need to store a custom key with ENV{key}="value"
 > in the database, which is imported on remove.


Kay,

Thank you very much. I suspected that something of the sort was 
happening; but I wasn't aware that custom keys for ENV were possible. 
(It's not on the man page.)

Here's my fix. I've created the following rules:

ACTION="add", SYSFS{product}="Flash Disk",  NAME="ums", 
RUN+="/etc/hotplug/usb/ums", ENV{flashdrive}="%p"

ACTION="remove", ENV{flashdrive}="%p", RUN+="/etc/hotplug/usb/ums"

The first rule sets, on an "add," the custom environment variable 
"flashdrive" to the value of DEVPATH (%p). The 2nd rule checks, on a 
"remove," to see if the devpath that's being removed is the one for the 
flash drive -- if so, the designated script runs.

-- 
  Moshe Yudkowsky
  work: http://www.Disaggregate.com
  book: http://www.PebbleAndAvalanche.com


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