mmdebstrap/hooks/merged-usr/extract00.sh

86 lines
2.7 KiB
Bash
Raw Permalink Normal View History

#!/bin/sh
set -eu
if [ "${MMDEBSTRAP_VERBOSITY:-1}" -ge 3 ]; then
set -x
fi
TARGET="$1"
# can_usrmerge_symlink() and can_usrmerge_symlink() are
# Copyright 2023 Helmut Grohne <helmut@subdivi.de>
# and part of the debootstrap source in /usr/share/debootstrap/functions
# https://salsa.debian.org/installer-team/debootstrap/-/merge_requests/96
# https://bugs.debian.org/104989
can_usrmerge_symlink() {
# Absolute symlinks can be relocated without problems.
test "${2#/}" = "$2" || return 0
while :; do
if test "${2#/}" != "$2"; then
# Handle double-slashes.
set -- "$1" "${2#/}"
elif test "${2#./}" != "$2"; then
# Handle ./ inside a link target.
set -- "$1" "${2#./}"
elif test "$2" = ..; then
# A parent directory symlink is ok if it does not
# cross the top level directory.
test "${1%/*/*}" != "$1" -a -n "${1%/*/*}"
return $?
elif test "${2#../}" != "$2"; then
# Symbolic link crossing / cannot be moved safely.
# This is prohibited by Debian Policy 10.5.
test "${1%/*/*}" = "$1" -o -z "${1%/*/*}" && return 1
set -- "${1%/*}" "${2#../}"
else
# Consider the symlink ok if its target does not
# contain a parent directory. When we fail here,
# the link target is non-minimal and doesn't happen
# in the archive.
test "${2#*/../}" = "$2"
return $?
fi
done
}
merge_usr_entry() {
# shellcheck disable=SC3043
local entry canon
canon="$TARGET/usr/${1#"$TARGET/"}"
test -h "$canon" &&
error 1 USRMERGEFAIL "cannot move %s as its destination exists as a symlink" "${1#"$TARGET"}"
if ! test -e "$canon"; then
mv "$1" "$canon"
return 0
fi
test -d "$1" ||
error 1 USRMERGEFAIL "cannot move non-directory %s as its destination exists" "${1#"$TARGET"}"
test -d "$canon" ||
error 1 USRMERGEFAIL "cannot move directory %s as its destination is not a directory" "${1#"$TARGET"}"
for entry in "$1/"* "$1/."*; do
# Some shells return . and .. on dot globs.
test "${entry%/.}" != "${entry%/..}" && continue
if test -h "$entry" && ! can_usrmerge_symlink "${entry#"$TARGET"}" "$(readlink "$entry")"; then
error 1 USRMERGEFAIL "cannot move relative symlink crossing top-level directory" "${entry#"$TARGET"}"
fi
# Ignore glob match failures
if test "${entry%'/*'}" != "${entry%'/.*'}" && ! test -e "$entry"; then
continue
fi
merge_usr_entry "$entry"
done
rmdir "$1"
}
# This is list includes all possible multilib directories. It must be
# updated when new multilib directories are being added. Hopefully,
# all new architectures use multiarch instead, so we never get to
# update this.
for dir in bin lib lib32 lib64 libo32 libx32 sbin; do
test -h "$TARGET/$dir" && continue
test -e "$TARGET/$dir" || continue
merge_usr_entry "$TARGET/$dir"
ln -s "usr/$dir" "$TARGET/$dir"
done