Starting helper programs - explicit check instead of just adding

Starting helper programs - explicit check instead of just adding

[Matthias Schwarzott]

Hi there!

Generally executing udev-helper programs located in /lib/udev works well 
(without specifying a path).
Only one rule I use, just does not work like one could think:

SUBSYSTEM="pnp", ENV{MODALIAS}!="?*", RUN+="/bin/sh -c 'while read id; 
do /lib/udev/modprobe.sh pnp:d$$id; done < /sys$devpath/id'"

Here I have to explicitly give the full path to modprobe.sh.

The code uses this to look for not fully qualified pathes:
if (strchr(argv[0], '/') = NULL) {
                strlcpy(program, "/lib/udev/", sizeof(program));
                strlcat(program, argv[0], sizeof(program));
                argv[0] = program;
        }
...
execv(argv[0], argv);

And that only looks at the main program started in the cmd-line and not what 
this shell does.

Is this something that could be changed?
By e.g. using some exec-call respecting path?
Or keeping the code as it is, but still adding /lib/udev to PATH for such 
embedded calls to work like one could assume with common-sense?

Matthias

-- 
Matthias Schwarzott (zzam)

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Re: Starting helper programs - explicit check instead of just adding

[Kay Sievers]

On 3/29/07, Matthias Schwarzott <zzam@gentoo.org> wrote:
> Generally executing udev-helper programs located in /lib/udev works well
> (without specifying a path).
> Only one rule I use, just does not work like one could think:
>
> SUBSYSTEM="pnp", ENV{MODALIAS}!="?*", RUN+="/bin/sh -c 'while read id;
> do /lib/udev/modprobe.sh pnp:d$$id; done < /sys$devpath/id'"
>
> Here I have to explicitly give the full path to modprobe.sh.

> And that only looks at the main program started in the cmd-line and not what
> this shell does.
>
> Is this something that could be changed?
> By e.g. using some exec-call respecting path?
> Or keeping the code as it is, but still adding /lib/udev to PATH for such
> embedded calls to work like one could assume with common-sense?

It's the expected behavior, we don't want to stat() all over the
place, to find the programs.
You can set the path with:
  ENV{PATH}="/lib/udev:/bin:/sbin"
in any earlier rule, and the udev-forked shell will find all the
commands in /lib/udev.

Thanks,
Kay

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