Re: udev not running new rules

[Peter Gordon <peter@pg-consultants.com>]

On Sun, 2007-08-12 at 21:28 +0200, Kay Sievers wrote:
> On Sun, 2007-08-12 at 22:03 +0300, Peter Gordon wrote:
> > On Sun, 2007-08-12 at 16:19 +0200, Kay Sievers wrote:
> > > On 8/12/07, Peter Gordon <peter@pg-consultants.com> wrote:
> > > >
> > > > I am using Debian Etch.
> > > >
> > > > I have the directory in /etc/udev/rules.d
> > > >
> > > > lrwxrwxrwx 1 root root   20 2007-06-19 16:52 020_permissions.rules -> ../permissions.rules
> > > > lrwxrwxrwx 1 root root   13 2007-06-19 16:52 udev.rules -> ../udev.rules
> > > > -rwxr-xr-x 1 root root  138 2007-07-29 14:28 z19_persistent-anet.rules
> > > > lrwxrwxrwx 1 root root   25 2007-06-19 16:52 z20_persistent-input.rules -> ../persistent-input.rules
> > > > lrwxrwxrwx 1 root root   19 2007-06-19 16:52 z20_persistent.rules -> ../persistent.rules
> > > > -rw-r--r-- 1 root root 1070 2007-06-19 17:09 z25_persistent-cd.rules
> > > > lrwxrwxrwx 1 root root   23 2007-06-26 00:57 z25_persistent-net.rules -> ../persistent-net.rules
> > > > lrwxrwxrwx 1 root root   12 2007-06-19 16:52 z50_run.rules -> ../run.rules
> > > > lrwxrwxrwx 1 root root   16 2007-06-19 16:52 z55_hotplug.rules -> ../hotplug.rules
> > > > lrwxrwxrwx 1 root root   29 2007-06-19 16:52 z75_cd-aliases-generator.rules -> ../cd-aliases-generator.rules
> > > >
> > > > Initially, the file ../persistent-net.rules does not exist.
> > > >
> > > > The rule z19_persistent-anet.rules is:
> > > >
> > > > PROGRAM="/var/www/lib/produce_persistent_rules.pl"
> > > >
> > > > The object of the program is to rename one of the NICs, and simply produces a rule
> > > > SUBSYSTEMS="pci", KERNELS="0000:09:01.0", NAME="ctl"
> > > >
> > > > It runs a Perl program that creates the file ../persistent-net.rules.
> > > >
> > > > After a reboot, the file is created, but udev claims that it doesn't exist.
> > > >
> > > > After a second reboot, udev manages to read the file successfully.
> > > >
> > > > Killing udev and restarting doesn't help.
> > > >
> > > > It seems that udev firstly checks which files exist. How can I get the new rule set to be run as soon as it is created?
> > > 
> > > Rules are just matches/actions for events. Adding or removing rules
> > > does nothing to any already existent device. Only the next event would
> > > be processed with the new rules. Does that explain your problem?
> > > 
> > 
> > I have deleted the soft link as suggested by Marco d'Itri and it didn't
> > help.
> > 
> > I understand about the already existing device.
> > 
> > If the event for a NIC occurs really early in the udev sequence, it
> > would seem that the z19_persistent-anet.rules is being run after the NIC
> > was created. 
> > 
> > I moved z19_persistent-anet.rules to 000z19_persistent-anet.rules to
> > force it to be the first rule.
> > 
> > It still creates the file, but doesn't manage to use the file until the
> > following reboot.
> > 
> > So I still don't have a handle on the problem. What would be the best
> > way to get debugging output?
> 
> Do you expect to create a rules file and get that file applied
> immediately to the running event? That doesn't work, rules are parsed
> in-memory and only read by the daemon not by the event process.
> 
> You need to apply the result of the rule creation in the same event,
> with the same rule that created the rules file for future events. Just
> look at the standard solution for persistent network interfaces that
> comes with udev, which probably just solves your problem anyway, or what
> do you miss from it?
> 
My problem is this. I need to create the rules file at boot up since the
devices available may change from boot to boot, and the PCI addresses
are not guaranteed to be the same.

So I need to create the rules file and then get those rules run.

I had a look at the persistent network interfaces but I can't see how
that helps, since the rules are already extant. 


Peter


> Kay
> 


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