Bug#665475: os-prober: follows symlinks in /dev/mapper/

[Alexis Rimbaud <alexis.rimbaud@gmail.com>]

Package: os-prober
Version: 1.49ubuntu1
Severity: normal

os-prober follows symbolic links in /dev/mapper/ which results in the
"root" parameter of the kernel being set to /dev/dm-<X>. This is an
issue because /dev/dm-<X> isn't guaranteed to map to the same logical
volume across reboots.

A possible fix would be to modify /usr/share/os-prober/common.sh to have:

---
if ! type mapdevfs >/dev/null 2>&1; then
  mapdevfs () {
    [ -n $(echo "$1" | grep "^/dev/mapper/") ] && echo "$1" || readlink -f "$1"
  }
fi
---

instead of:

---
if ! type mapdevfs >/dev/null 2>&1; then
  mapdevfs () {
    readlink -f "$1"
  }
fi
---

Regards,
Alexis