Why not picking up ENV variables?

Why not picking up ENV variables?

[Moshe Yudkowsky]

Here's the output of udevmonitor --env:

UDEV  [1143983665.856252] add@/block/sdb
UDEV_LOG=3
ACTION­d
DEVPATH=/block/sdb
SUBSYSTEM=block
SEQNUM#89
MINOR\x16
MAJOR=8
PHYSDEVPATH=/devices/pci0000:00/0000:00:10.3/usb4/4-4/4-4:1.0/host6/target6:0:0/6:0:0:0
PHYSDEVBUS=scsi
PHYSDEVDRIVER=sd
UDEVD_EVENT=1
ID_VENDOR=iriver
ID_MODEL=MassStorage_Disc
ID_REVISION\001
ID_SERIAL=iriver_MassStorage_Disc
ID_TYPE=disk
ID_BUS=usb
ID_PATH=pci-0000:00:10.3-usb-0:4:1.0-scsi-0:0:0:0
DEVNAME=/dev/scsi/host6/bus0/target0/lun0/disc
DEVLINKS=/dev/sdb /dev/discs/disc2/disc 
/dev/disk/by-id/usb-iriver_MassStorage_Disc 
/dev/disk/by-path/pci-0000:00:10.3-usb-0:4:1.0-scsi-0:0:0:0

Now, I will tell you the truth: I have not yet been able to find any 
documentation that states, explicitly, what variables are part of SYSFS 
and what variables are part of ENV. I can figure out -- only by running 
udevinfo and reading the "sysfs" prefixes -- what info is SYSFS only.

However, when I read (e.g.) persistent.rules, I get the impression that 
some of the info that's in the udevmonitor --env printout isn't really 
part of the standard environment. Instead, it's imported there by path_id.

It'd be very nice to find documentation that explains what variables are 
part of ENV and which are not, by default.

In any case, here are two rules:

SUBSYSTEM="block", ACTION="add", ENV{ID_VENDOR}="iriver", 
ENV{ID_SERIAL}="iriver_MassStorage_Disc", SYMLINK+="iriver", 
RUN+="/etc/hotplug/usb/iriver"

SUBSYSTEM="block", ACTION="remove",  ENV{ID_VENDOR}="iriver", 
ENV{ID_SERIAL}="iriver_MassStorage_Disc", RUN+="/etc/hotplug/usb/iriver"

Neither of these two rules will run. I've tried different variations, 
including SYMLINK= instead of SYMLINK+=, leaving off ID_VENDOR matching, 
etc.

If I use SYSFS variables, I can easily match that "add," but the goal is 
to also be able to match on "remove."

Now, what's interesting is that these very same variables are used by 
persistent.rules to create /dev/disk/by-*. So, for example, there's a 
device called /dev/disk/by-id/usb-iriver_MassStorage_Disc.

I will start some experiments with path_id and the order the files 
execute, but if someone wants to toss me a hint, it'll save me a lot of 
time.

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


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Re: Why not picking up ENV variables?

[Moshe Yudkowsky]

In another test, I've modified the rules:

SUBSYSTEM="block" IMPORT{program}="path_id $devpath"

SUBSYSTEM="block", ACTION="add", ENV{ID_VENDOR}="iriver", 
ENV{ID_SERIAL}="iriver_MassStorage_Disc", SYMLINK+="iriver", 
RUN+="/etc/hotplug/usb/iriver", ENV{REMOVE_CMD}="/etc/hotplug/usb/iriver 
remove"

SUBSYSTEM="block", ACTION="remove",  ENV{ID_VENDOR}="iriver", 
ENV{ID_SERIAL}="iriver_MassStorage_Disc", RUN+="/etc/hotplug/usb/iriver 
remove"

and I've also set them to run *after* the persistent.rules file. This 
should make certain that ID_VENDOR and ID_PATH are in the ENV -- even 
though I've certainly seen them in udevinfo printouts even without 
adding path_id myself.

While "add" works, the "remove" does not work. Furthermore, even thought 
run.rules executes, the ENV{REMOVE_CMD} that I've set does not run.

Help?

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


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Re: Why not picking up ENV variables?

[Andrey Borzenkov]

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On Sunday 02 April 2006 18:58, Moshe Yudkowsky wrote:
> In another test, I've modified the rules:
>
> SUBSYSTEM="block" IMPORT{program}="path_id $devpath"
>
> SUBSYSTEM="block", ACTION="add", ENV{ID_VENDOR}="iriver",
> ENV{ID_SERIAL}="iriver_MassStorage_Disc", SYMLINK+="iriver",
> RUN+="/etc/hotplug/usb/iriver", ENV{REMOVE_CMD}="/etc/hotplug/usb/iriver
> remove"
>
> SUBSYSTEM="block", ACTION="remove",  ENV{ID_VENDOR}="iriver",
> ENV{ID_SERIAL}="iriver_MassStorage_Disc", RUN+="/etc/hotplug/usb/iriver
> remove"
>
> and I've also set them to run *after* the persistent.rules file. This
> should make certain that ID_VENDOR and ID_PATH are in the ENV -- even
> though I've certainly seen them in udevinfo printouts even without
> adding path_id myself.
>
> While "add" works, the "remove" does not work.

Unless I misread the code, stored environment is not available when matching 
device event; it is imported after that, immediately before RUN programs are 
going to be run. As most other callouts are run only on ACTION="add", it 
means environment is mostly not available for remove rules.

> Furthermore, even thought 
> run.rules executes, the ENV{REMOVE_CMD} that I've set does not run.
>

If I am right, it does not run for the same reason - ENV{REMOVE_CMD} is not 
defined when rule runs.

> Help?

Could you try if this patch helps?

diff --git a/udev_device.c b/udev_device.c
index 5db2709..cd84a0a 100644
- --- a/udev_device.c
+++ b/udev_device.c
@@ -101,6 +101,7 @@ int udev_device_event(struct udev_rules
        if (major(udev->devt) != 0 && strcmp(udev->action, "remove") = 0) {
                struct name_entry *name_loop;

+               udev_db_get_device(udev, udev->dev->devpath);
                udev_rules_get_run(rules, udev);
                if (udev->ignore_device) {
                        info("device event will be ignored");

- -andrey
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Re: Why not picking up ENV variables?

[Moshe Yudkowsky]

> Unless I misread the code, stored environment is not available when matching 
> device event; it is imported after that, immediately before RUN programs are 
> going to be run. As most other callouts are run only on ACTION="add", it 
> means environment is mostly not available for remove rules.

I will certainly try to find time to run against this patch. Is there a 
"best practices" method for "remove" events? If sysfs isn't available, 
and I can't import to the environment via path_id, then what's left to 
match against?

-- 
Moshe Yudkowsky * moshe@pobox.com * www.pobox.com/~moshe
  "The odds are good, but the goods are odd."
    	     -- Alaskan women, on the high ratio of men to women in Alaska


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Re: Why not picking up ENV variables?

[Moshe Yudkowsky]

This patch didn't seem to help.

> Could you try if this patch helps?
> 
> diff --git a/udev_device.c b/udev_device.c
> index 5db2709..cd84a0a 100644
> - --- a/udev_device.c
> +++ b/udev_device.c
> @@ -101,6 +101,7 @@ int udev_device_event(struct udev_rules
>         if (major(udev->devt) != 0 && strcmp(udev->action, "remove") = 0) {
>                 struct name_entry *name_loop;
> 
> +               udev_db_get_device(udev, udev->dev->devpath);
>                 udev_rules_get_run(rules, udev);
>                 if (udev->ignore_device) {
>                         info("device event will be ignored");
> 
> - -andrey

(1) The relevant lines in udev_device.c now read:

	if (major(udev->devt) != 0 && strcmp(udev->action, "remove") = 0) {
		struct name_entry *name_loop;

		udev_db_get_device(udev, udev->dev->devpath);
		udev_rules_get_run(rules, udev);
		if (udev->ignore_device) {
			info("device event will be ignored");
			return 0;
		}

and then I simply ran:

make
make install

in my normal environment. I didn't make or install, e.g., ata-id.


(2) On unplug, the output of udevmonitor --env  reads:

> UDEV  [1144149290.702789] remove@/block/sdb
> UDEV_LOG=3
> ACTION=remove
> DEVPATH=/block/sdb
> SUBSYSTEM=block
> SEQNUM374
> MINOR\x16
> MAJOR=8
> PHYSDEVPATH=/devices/pci0000:00/0000:00:10.3/usb4/4-4/4-4:1.0/host21/target21:0:0/21:0:0:0
> PHYSDEVBUS=scsi
> PHYSDEVDRIVER=sd
> UDEVD_EVENT=1
> DEVLINKS=/dev/sdb /dev/discs/disc2/disc /dev/disk/by-id/usb-iriver_MassStorage_Disc /dev/disk/by-path/pci-0000:00:10.3-usb-0:4:1.0-scsi-0:0:0:0 /dev/iriverDEVNAME=/dev/scsi/host21/bus0/target0/lun0/disc
> ID_VENDOR=iriver
> ID_MODEL=MassStorage_Disc
> ID_REVISION\001
> ID_SERIAL=iriver_MassStorage_Disc
> ID_TYPE=disk
> ID_BUS=usb
> ID_PATH=pci-0000:00:10.3-usb-0:4:1.0-scsi-0:0:0:0
> REMOVE_CMD=/etc/hotplug/usb/iriver remove


(3) the rules are (the "add" rule works, the "remove" does not):

SUBSYSTEM="block" IMPORT{program}="path_id $devpath"

SUBSYSTEM="block", ACTION="add", ENV{ID_VENDOR}="iriver", 
ENV{ID_SERIAL}="iriver_MassStorage_Disc", SYMLINK+="iriver", 
RUN+="/etc/hotplug/usb/iriver", ENV{REMOVE_CMD}="/etc/hotplug/usb/iriver 
remove"

SUBSYSTEM="block", ACTION="remove",  ENV{ID_VENDOR}="iriver", 
ENV{ID_SERIAL}="iriver_MassStorage_Disc", RUN+="/etc/hotplug/usb/iriver"


Please let me know what further tests to run.


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


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Re: Why not picking up ENV variables?

[Andrey Borzenkov]

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On Tuesday 04 April 2006 15:20, Moshe Yudkowsky wrote:
> This patch didn't seem to help.
>
> > Could you try if this patch helps?
> >

right; the patch below does (verified with exact copy of your rule).

- -andrey

diff --git a/udev_device.c b/udev_device.c
index 5db2709..6ee6b13 100644
- --- a/udev_device.c
+++ b/udev_device.c
@@ -101,6 +101,10 @@ int udev_device_event(struct udev_rules
        if (major(udev->devt) != 0 && strcmp(udev->action, "remove") = 0) {
                struct name_entry *name_loop;

+               udev_db_get_device(udev, udev->dev->devpath);
+               /* restore stored persistent data */
+               list_for_each_entry(name_loop, &udev->env_list, node)
+                       putenv(name_loop->name);
                udev_rules_get_run(rules, udev);
                if (udev->ignore_device) {
                        info("device event will be ignored");
@@ -109,9 +113,6 @@ int udev_device_event(struct udev_rules
                /* get data from db, remove db-entry, delete node */
                retval = udev_remove_device(udev);

- -               /* restore stored persistent data */
- -               list_for_each_entry(name_loop, &udev->env_list, node)
- -                       putenv(name_loop->name);
                return retval;
        }

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Re: Why not picking up ENV variables?

[Moshe Yudkowsky]

> right; the patch below does (verified with exact copy of your rule).

Andrey,

Thank you. This patch works. I tested it with udev-089 (which, I finally 
realized, was the not the package you were working with).

I see not only the "remove" I expect from the rule, but also the 
REMOVE_CMD event I created in the ENV{REMOVE_CMD}. This is excellent, 
because it means that I can actually control devices on remove.

Thank you very much for your help.

-- 
Moshe Yudkowsky * moshe@pobox.com * www.pobox.com/~moshe
  "You may fire when ready, Gridley." -- Commodore George Dewey


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