The ldd output can contain the variable $LIB, which is a documented feature of
ldd. In a previous commit [0], dracut-install received support for this
variable, but that was later reverted [1] due to issues [2][3] on Gentoo ARM64.
The part before '=>' does not necessarily refer to an existing file (e.g. due
to the usage of $LIB) and thus [1] could be seen as a regression to anyone
that uses this ldd feature. This PR combines both cases together and whenever
it find a '$' character (i.e. a variable) on the left side of the '=>' symbol,
it uses the right hand path (and thus uses evaluation done by ldd), otherwise
falls back to the behavior set by [1].
Reproducer that was presented to me:
$ grep "ibz.so" /etc/ld.so.preload || cat << EOF >> /etc/ld.so.preload
/\$LIB/libz.so.1.2.11
EOF
$ mkdir -p /var/tmp/dracut.xitk6p/initramfs
$ strace /usr/lib/dracut/dracut-install -D /var/tmp/dracut.xitk6p/initramfs -l /bin/bash 2>&1|grep ibz
$ rm -rf /var/tmp/dracut.xitk6p/
[0] 45404a2
[1] 6d886bb
[2] #471
[3] https://bugs.gentoo.org/667752
Jaroslav Jindrak