problem with a specific ACTION=="remove" udev rule

problem with a specific ACTION=="remove" udev rule

[Ludovic Rousseau]

Hello,

I use udev to run a program when a USB device is connected or removed.
The USB device is a CCID smart card reader [1] and the program is a
smart card resource manager. I use udev to dynamically add and remove
smart card reader to/from the smart card resource manager.

My rules file is:
ACTION="remove", RUN+="/usr/sbin/pcscd --hotplug"

BUS="usb", SYSFS{bInterfaceClass}="0b", ACTION="add",
RUN+="/usr/sbin/pcscd --hotplug"

I do not need any kernel driver to use the device. Everything is in user space.

I would like to also specify SYSFS{bInterfaceClass}="0b" (specific to
CCID smart card readers) for the remove action but that does not work.
The rule is then not executed. Of course, if I do not use
SYSFS{bInterfaceClass}="0b" the rule is executed every time a USB
device is removed, even if it is not a smart card reader.

Why can't I specify the SYSFS{bInterfaceClass} = "0b" in a remove rule?

Am I doing something wrong?

I use udev 079-0ubuntu34 on a Ubuntu Dapper system (Linux 2.6.15-23-686).
I also tried with a more recent udev version, version 100 on Debian
testing, with Linux 2.6.18 but with the same results.

Thanks,

[1] http://pcsclite.alioth.debian.org/ccid.html

-- 
  Dr. Ludovic Rousseau

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Re: problem with a specific ACTION=="remove" udev rule

[Kay Sievers]

On 11/14/06, Ludovic Rousseau <ludovic.rousseau@gmail.com> wrote:
> Hello,
>
> I use udev to run a program when a USB device is connected or removed.
> The USB device is a CCID smart card reader [1] and the program is a
> smart card resource manager. I use udev to dynamically add and remove
> smart card reader to/from the smart card resource manager.
>
> My rules file is:
> ACTION="remove", RUN+="/usr/sbin/pcscd --hotplug"

...

> Why can't I specify the SYSFS{bInterfaceClass} = "0b" in a remove rule?

Because, there is no sysfs-attribute left to look at, at the time you
get a "remove" event.

Kay

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Re: Re: problem with a specific ACTION=="remove" udev rule

[Ludovic Rousseau]

On 14/11/06, Kay Sievers <kay.sievers@vrfy.org> wrote:
> On 11/14/06, Ludovic Rousseau <ludovic.rousseau@gmail.com> wrote:
> > Hello,
> >
> > I use udev to run a program when a USB device is connected or removed.
> > The USB device is a CCID smart card reader [1] and the program is a
> > smart card resource manager. I use udev to dynamically add and remove
> > smart card reader to/from the smart card resource manager.
> >
> > My rules file is:
> > ACTION="remove", RUN+="/usr/sbin/pcscd --hotplug"
>
> ...
>
> > Why can't I specify the SYSFS{bInterfaceClass} = "0b" in a remove rule?
>
> Because, there is no sysfs-attribute left to look at, at the time you
> get a "remove" event.

So I guess I have no solution other than to be called for every USB
device removed?

Thanks,

-- 
 Dr. Ludovic Rousseau

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Re: problem with a specific ACTION=="remove" udev rule

[Andreas Jellinghaus]

Ludovic Rousseau wrote:
> So I guess I have no solution other than to be called for every USB
> device removed?

if you have an open file handle to the device, simply use poll or
select and it will return an error.

note: with recent kernels this is fine. with early 2.6 kernels,
you only get the error once the timeout is reached, and if you
don't have a timeout, select/poll never return at all. thats
why I use poll with one second timeouts in openct.

Andreas

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Re: problem with a specific ACTION=="remove" udev rule

[Andrey Borzenkov]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Tuesday 14 November 2006 19:00, Ludovic Rousseau wrote:
> On 14/11/06, Kay Sievers <kay.sievers@vrfy.org> wrote:
> > On 11/14/06, Ludovic Rousseau <ludovic.rousseau@gmail.com> wrote:
> > > Hello,
> > >
> > > I use udev to run a program when a USB device is connected or removed.
> > > The USB device is a CCID smart card reader [1] and the program is a
> > > smart card resource manager. I use udev to dynamically add and remove
> > > smart card reader to/from the smart card resource manager.
> > >
> > > My rules file is:
> > > ACTION="remove", RUN+="/usr/sbin/pcscd --hotplug"
> >
> > ...
> >
> > > Why can't I specify the SYSFS{bInterfaceClass} = "0b" in a remove
> > > rule?
> >
> > Because, there is no sysfs-attribute left to look at, at the time you
> > get a "remove" event.
>
> So I guess I have no solution other than to be called for every USB
> device removed?
>

ACTION="add" SYSFS{bInterfaceClass}="0b" ENV{NEED_PCSCD_ON_REMOVE}="true"
ACTION="remove" ENV{NEED_PCSCD_ON_REMOVE}="true" 
RUN+="/usr/sbin/pcscd --hotplug"
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Re: problem with a specific ACTION=="remove" udev rule

[Ludovic Rousseau]

On 14/11/06, Andrey Borzenkov <arvidjaar@mail.ru> wrote:
> On Tuesday 14 November 2006 19:00, Ludovic Rousseau wrote:
> > On 14/11/06, Kay Sievers <kay.sievers@vrfy.org> wrote:
> > > On 11/14/06, Ludovic Rousseau <ludovic.rousseau@gmail.com> > >

> > Why can't I specify the SYSFS{bInterfaceClass} = "0b" in a remove
> > > > rule?
> > >
> > > Because, there is no sysfs-attribute left to look at, at the time you
> > > get a "remove" event.
> >
> > So I guess I have no solution other than to be called for every USB
> > device removed?
> >
>
> ACTION="add" SYSFS{bInterfaceClass}="0b" ENV{NEED_PCSCD_ON_REMOVE}="true"
> ACTION="remove" ENV{NEED_PCSCD_ON_REMOVE}="true"
> RUN+="/usr/sbin/pcscd --hotplug"

The problem is that ENV{} is only valid for the command executed by
RUN. But I have 3 different pcscd process in my case:
a. a main pcscd started at boot
b. a pcscd --hotplug started when a reader is connected. This process
will send a signal to the main pcscd to ask for a USB rescan (to add a
device) and then exit
c. a pcscd --hotplug started when a reader is removed. This process
will send a signal to the main pcscd to ask for a USB rescan (to
remove a device) and then exit

So the environment created by ENV{NEED_PCSCD_ON_REMOVE}="true" for b
is lost when b finishes.

I don't think udev can help me here. If I am correct udev knows a
device was removed but cannot tell which one precisely.

Thanks

-- 
  Dr. Ludovic Rousseau

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Re: problem with a specific ACTION=="remove" udev rule

[Andrey Borzenkov]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Wednesday 15 November 2006 12:06, Ludovic Rousseau wrote:
> > ACTION="add" SYSFS{bInterfaceClass}="0b"
> > ENV{NEED_PCSCD_ON_REMOVE}="true" ACTION="remove"
> > ENV{NEED_PCSCD_ON_REMOVE}="true"
> > RUN+="/usr/sbin/pcscd --hotplug"
>
> The problem is that ENV{} is only valid for the command executed by
> RUN.

Have you actually tried it?
[...]
> I don't think udev can help me here. If I am correct udev knows a
> device was removed but cannot tell which one precisely.
>

That's wrong.

- -andrey
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Re: problem with a specific ACTION=="remove" udev rule

[Ludovic Rousseau]

On 15/11/06, Andrey Borzenkov <arvidjaar@mail.ru> wrote:
> On Wednesday 15 November 2006 12:06, Ludovic Rousseau wrote:
> > > ACTION="add" SYSFS{bInterfaceClass}="0b"
> > > ENV{NEED_PCSCD_ON_REMOVE}="true" ACTION="remove"
> > > ENV{NEED_PCSCD_ON_REMOVE}="true"
> > > RUN+="/usr/sbin/pcscd --hotplug"
> >
> > The problem is that ENV{} is only valid for the command executed by
> > RUN.
>
> Have you actually tried it?

Yes. And it failed on my Ubuntu Dapper system.
I now tried it on Debian testing and it works. I will try again on
Ubuntu Dapper to be sure.

Thanks,

PS: I see you do not use any comma in you example. My udev(7) manpage says:
" A rule may consists of a list of one or more key value pairs
separated by a comma. "

-- 
  Dr. Ludovic Rousseau

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Re: problem with a specific ACTION=="remove" udev rule

[Andrey Borzenkov]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Wednesday 15 November 2006 23:33, Ludovic Rousseau wrote:
> Yes. And it failed on my Ubuntu Dapper system.
> I now tried it on Debian testing and it works. I will try again on
> Ubuntu Dapper to be sure.
>

well, I really do not remember since when environment is preserved for remove 
events (I guess since 059 but I may be wrong here).

> PS: I see you do not use any comma in you example. My udev(7) manpage says:
> " A rule may consists of a list of one or more key value pairs
> separated by a comma. "

this seems to work both ways. I have no idea if this is intentional.
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Re: problem with a specific ACTION=="remove" udev rule

[Ludovic Rousseau]

On 16/11/06, Andrey Borzenkov <arvidjaar@mail.ru> wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> On Wednesday 15 November 2006 23:33, Ludovic Rousseau wrote:
> > Yes. And it failed on my Ubuntu Dapper system.
> > I now tried it on Debian testing and it works. I will try again on
> > Ubuntu Dapper to be sure.
> >
>
> well, I really do not remember since when environment is preserved for remove
> events (I guess since 059 but I may be wrong here).

I rechecked and on my Ubuntu system it does not work.

When I add the device I have (logged using udevmonitor --env)

UEVENT[1164038254.909080] add@/devices/pci0000:00/0000:00:1d.3/usb4/4-1/4-1.3
ACTION­d
DEVPATH=/devices/pci0000:00/0000:00:1d.3/usb4/4-1/4-1.3
SUBSYSTEM=usb
SEQNUM582
PHYSDEVBUS=usb
PHYSDEVDRIVER=usb

UEVENT[1164038254.910067] add@/devices/pci0000:00/0000:00:1d.3/usb4/4-1/4-1.3/4-
1.3:1.0
ACTION­d
DEVPATH=/devices/pci0000:00/0000:00:1d.3/usb4/4-1/4-1.3/4-1.3:1.0
SUBSYSTEM=usb
SEQNUM583
PHYSDEVBUS=usb
DEVICE=/proc/bus/usb/004/009
PRODUCTŽ6/3437/100
TYPE=0/0/0
INTERFACE\x11/0/0
MODALIAS=usb:v08E6p3437d0100dc00dsc00dp00ic0Bisc00ip00

UEVENT[1164038254.910123] add@/class/usb_device/usbdev4.9
ACTION­d
DEVPATH=/class/usb_device/usbdev4.9
SUBSYSTEM=usb_device
SEQNUM584
PHYSDEVPATH=/devices/pci0000:00/0000:00:1d.3/usb4/4-1/4-1.3
PHYSDEVBUS=usb
PHYSDEVDRIVER=usb
MAJOR\x189
MINOR92

UDEV  [1164038254.930194] add@/devices/pci0000:00/0000:00:1d.3/usb4/4-1/4-1.3
UDEV_LOG=3
ACTION­d
DEVPATH=/devices/pci0000:00/0000:00:1d.3/usb4/4-1/4-1.3
SUBSYSTEM=usb
SEQNUM582
PHYSDEVBUS=usb
PHYSDEVDRIVER=usb
UDEVD_EVENT=1

UDEV  [1164038255.099240] add@/devices/pci0000:00/0000:00:1d.3/usb4/4-1/4-1.3/4-
1.3:1.0
UDEV_LOG=3
ACTION­d
DEVPATH=/devices/pci0000:00/0000:00:1d.3/usb4/4-1/4-1.3/4-1.3:1.0
SUBSYSTEM=usb
SEQNUM583
PHYSDEVBUS=usb
DEVICE=/proc/bus/usb/004/009
PRODUCTŽ6/3437/100
TYPE=0/0/0
INTERFACE\x11/0/0
MODALIAS=usb:v08E6p3437d0100dc00dsc00dp00ic0Bisc00ip00
UDEVD_EVENT=1
NEED_PCSCD_ON_REMOVE=true

UDEV  [1164038255.169725] add@/class/usb_device/usbdev4.9
UDEV_LOG=3
ACTION­d
DEVPATH=/class/usb_device/usbdev4.9
SUBSYSTEM=usb_device
SEQNUM584
PHYSDEVPATH=/devices/pci0000:00/0000:00:1d.3/usb4/4-1/4-1.3
PHYSDEVBUS=usb
PHYSDEVDRIVER=usb
MAJOR\x189
MINOR92
UDEVD_EVENT=1
USB_BUS\04
USB_DEV\09
DEVNAME=/dev/bus/usb/004/009



I can see the "NEED_PCSCD_ON_REMOVE=true"
But when I remove the device I have:

UEVENT[1164038257.455921] remove@/devices/pci0000:00/0000:00:1d.3/usb4/4-1/4-1.3
/4-1.3:1.0
ACTION=remove
DEVPATH=/devices/pci0000:00/0000:00:1d.3/usb4/4-1/4-1.3/4-1.3:1.0
SUBSYSTEM=usb
SEQNUM585
PHYSDEVBUS=usb
DEVICE=/proc/bus/usb/004/009
PRODUCTŽ6/3437/100
TYPE=0/0/0
INTERFACE\x11/0/0
MODALIAS=usb:v08E6p3437d0100dc00dsc00dp00ic0Bisc00ip00

UEVENT[1164038257.455952] remove@/class/usb_device/usbdev4.9
ACTION=remove
DEVPATH=/class/usb_device/usbdev4.9
SUBSYSTEM=usb_device
SEQNUM586
PHYSDEVPATH=/devices/pci0000:00/0000:00:1d.3/usb4/4-1/4-1.3
PHYSDEVBUS=usb
PHYSDEVDRIVER=usb
MAJOR\x189
MINOR92

UEVENT[1164038257.455967] remove@/devices/pci0000:00/0000:00:1d.3/usb4/4-1/4-1.3
ACTION=remove
DEVPATH=/devices/pci0000:00/0000:00:1d.3/usb4/4-1/4-1.3
SUBSYSTEM=usb
SEQNUM587
PHYSDEVBUS=usb

UDEV  [1164038257.457873] remove@/devices/pci0000:00/0000:00:1d.3/usb4/4-1/4-1.3
/4-1.3:1.0
UDEV_LOG=3
ACTION=remove
DEVPATH=/devices/pci0000:00/0000:00:1d.3/usb4/4-1/4-1.3/4-1.3:1.0
SUBSYSTEM=usb
SEQNUM585
PHYSDEVBUS=usb
DEVICE=/proc/bus/usb/004/009
PRODUCTŽ6/3437/100
TYPE=0/0/0
INTERFACE\x11/0/0
MODALIAS=usb:v08E6p3437d0100dc00dsc00dp00ic0Bisc00ip00
UDEVD_EVENT=1

UDEV  [1164038257.462036] remove@/class/usb_device/usbdev4.9
UDEV_LOG=3
ACTION=remove
DEVPATH=/class/usb_device/usbdev4.9
SUBSYSTEM=usb_device
SEQNUM586
PHYSDEVPATH=/devices/pci0000:00/0000:00:1d.3/usb4/4-1/4-1.3
PHYSDEVBUS=usb
PHYSDEVDRIVER=usb
MAJOR\x189
MINOR92
UDEVD_EVENT=1
DEVNAME=/dev/bus/usb/004/009
USB_BUS\04
USB_DEV\09

UDEV  [1164038257.463850] remove@/devices/pci0000:00/0000:00:1d.3/usb4/4-1/4-1.3
UDEV_LOG=3
ACTION=remove
DEVPATH=/devices/pci0000:00/0000:00:1d.3/usb4/4-1/4-1.3
SUBSYSTEM=usb
SEQNUM587
PHYSDEVBUS=usb
UDEVD_EVENT=1

And no NEED_PCSCD_ON_REMOVE is defined.

I use udev 079-0ubuntu34 and Linux 2.6.15-23-686.

I used another solution so it is not really a problem for me now. It
is just to complete my report.

Thanks to all,

-- 
  Dr. Ludovic Rousseau

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