Bug#568317: linux-image-* postinst did not correctly run lilo

[paul.szabo@sydney.edu.au]

Niko Tyni wrote:

> Reassigning now. ...

Thanks.

> ... you could probably follow up and explain what exactly was incorrect
> about running lilo.

Looking at my  /var/lib/dpkg/info/linux-image-*.postinst files, I see in
the code reading and parsing $CONF_LOC = '/etc/kernel-img.conf':

      ...
      $do_symlink      = "" if /do_symlinks\s*=\s*(no|false|0)\s*$/ig;
      ...
      $do_bootloader   = "Yes" if /do_bootloader\s*=\s*(yes|true|1)\s*$/ig;
      $explicit_do_loader = "YES" if /do_bootloader\s*=\s*(yes|true|1)\s*$/ig;
      ...

Most of the match patterns are used once only; using /g on them is not
necessary, and is probably wasteful (though perl is fast enough to
handle such things).

The pattern /do_bootloader.../ig is used twice. The first one may match;
the second one will surely not match because of the spurious /g, thus
explicit_do_loader will never be set (and lilo not run, or run after a
question left un-answered in unattended runs of "apt-get install").

---

Minor issues, while I am criticizing perl style...

These patterns are anchored at the end, should also be anchored at the
beginning (and with explicit m//) like:

      $do_symlink      = "" if m/^\s*do_symlinks\s*=\s*(no|false|0)\s*$/i;
      ...
      $image_dest      = "$1"  if m/^\s*image_dest\s*=\s*(\S+)\s*$/i;

I wonder about the need to use my() in a single-level script.

---

Cheers, Paul

Paul Szabo   psz@maths.usyd.edu.au   http://www.maths.usyd.edu.au/u/psz/
School of Mathematics and Statistics   University of Sydney    Australia