toby's Journal: so you unmerge'd gcc AND glibc. What now?

After a friend (honest!) did this to his Gentoo laptop, I devised the following rescue method:

1. Boot from a Gentoo CD.

2. mount the system's root partition, e.g. on /mnt/tmp:

mkdir /mnt/tmp
mount /dev/sda6 /mnt/tmp

(Device name will be different on your system. If you're not sure which partition is your root partition, you can inspect the partition table with e.g. fdisk /dev/hda but don't change anything! Print partition table and look for a partition of the right size, marked "Linux" partition. If your filesystem layout is not a single / partition, you'll need to mount the others as needed under /mnt/tmp.)

3. quickpkg glibc and note the path/package archive name.

4. Install the glibc package archive on the sick system:

ROOT=/mnt/tmp PORTAGE_CONFIGROOT=/mnt/tmp emerge -p --oneshot --nodeps /usr/portage/packages/sys-libs/glibc-2.4-r3.tbz2

(putting correct path to package archive). Note command is one line and -p means "pretend"; this is a dry run.

You'll see a bunch of warnings, for instance that "emerging by path is broken and may not work". Ignore them. If nothing else seems amiss, remove -p and re-run the emerge.

5. Repeat steps 3 and 4 for package 'gcc'.

6. Reboot. Run a gcc-config -l (dash-ell); it may complain about a broken gcc profile, in which case run gcc-config -f 1 (dash-f, space, one). You will then want to do something like:

emerge -eav system
emerge -eav world

to restore your system to a sane state since we just did an 'instant' upgrade to gcc & glibc (or a downgrade, depending on the CD you booted from).

(Information at upgrading gcc and change CHOST may also be helpful.)