[Pkg-raspi-maintainers] Bug#1009654: fixed: patch attached (udev rule command truncation)

[2014.stefanandreiionut at gmail.com]

Control: tags 1009654 + patch

Attached is a patch fixing the udev rule truncation.

Root cause: the PROGRAM= value in debian/rpi.gpio-common.udev's third
rule substitutes %p eight separate times (four in the chown arguments,
four in the chmod arguments). udev performs this substitution into the
rule text before invoking /bin/sh, so a deeply nested device path (e.g.
reached through a chain of USB hubs) gets multiplied by 8x in the final
command string, which is what overruns udev's ~1023-character internal
limit on PROGRAM values and produces the truncation described in the
original report.

Fix: substitute %p once into a shell variable ($p, escaped as $$p so
udev itself doesn't try to interpret it as one of its own $-prefixed
specifiers) and reuse that variable for all eight references instead of
re-substituting %p each time. This cuts the multiplier from 8x to 1x.

Verified:
- udevadm verify reports the patched rule file as syntactically valid
- Simulated against a realistic deeply-nested USB-hub sysfs path: the
  original rule produces a 1515-character command (over the limit,
  reproducing the reported truncation); the patched rule produces a
  310-character command for the same path (comfortably under it)
- Patch applies cleanly against a fresh pristine 0.7.1~a4-1.2 source tree

The reporter's own suggested alternative (splitting into multiple
shorter PROGRAM rules) would also work but only reduces the multiplier
by a constant factor rather than addressing why the substitution
happens repeatedly in the first place; this patch is a smaller diff
with a larger safety margin.

Changes:
- debian/rpi.gpio-common.udev (one line changed)
- debian/changelog
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