future-install-scripts/arch-chroot.in
2024-04-07 00:30:43 +08:00

125 lines
3.1 KiB
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#!/bin/bash
# SPDX-License-Identifier: GPL-2.0-only
shopt -s extglob
unshare=0
keepresolvconf=0
m4_include(common)
usage() {
cat <<EOF
usage: ${0##*/} chroot-dir [command] [arguments...]
-h Print this help message
-N Run in unshare mode as a regular user
-u <user>[:group] Specify non-root user and optional group to use
-r Do not change the resolv.conf within the chroot
If 'command' is unspecified, ${0##*/} will launch /bin/bash.
Note that when using arch-chroot, the target chroot directory *should* be a
mountpoint. This ensures that tools such as pacman(8) or findmnt(8) have an
accurate hierarchy of the mounted filesystems within the chroot.
If your chroot target is not a mountpoint, you can bind mount the directory on
itself to make it a mountpoint, i.e. 'mount --bind /your/chroot /your/chroot'.
EOF
}
resolve_link() {
local target=$1
local root=$2
# If a root was given, make sure it ends in a slash.
[[ -n $root && $root != */ ]] && root=$root/
while [[ -L $target ]]; do
target=$(readlink -m "$target")
# If a root was given, make sure the target is under it.
# Make sure to strip any leading slash from target first.
[[ -n $root && $target != $root* ]] && target=$root${target#/}
done
printf %s "$target"
}
chroot_add_resolv_conf() {
local chrootdir=$1
local src
local dest="$chrootdir/etc/resolv.conf"
src=$(resolve_link /etc/resolv.conf)
# If we don't have a source resolv.conf file, there's nothing useful we can do.
[[ -e $src ]] || return 0
if [[ ! -e "$dest" && ! -h "$dest" ]]; then
# There may be no resolv.conf in the chroot. In this case, we'll just exit.
# The chroot environment must not be concerned with DNS resolution.
return 0
fi
chroot_add_mount "$src" "$dest" -c --bind
}
arch-chroot() {
(( EUID == 0 )) || die 'This script must be run with root privileges'
[[ -d $chrootdir ]] || die "Can't create chroot on non-directory %s" "$chrootdir"
$setup "$chrootdir" || die "failed to setup chroot %s" "$chrootdir"
if (( ! keepresolvconf )); then
chroot_add_resolv_conf "$chrootdir" || die "failed to setup resolv.conf"
fi
if ! mountpoint -q "$chrootdir"; then
warning "$chrootdir is not a mountpoint. This may have undesirable side effects."
fi
chroot_args=()
[[ $userspec ]] && chroot_args+=(--userspec "$userspec")
SHELL=/bin/bash $pid_unshare chroot "${chroot_args[@]}" -- "$chrootdir" "${args[@]}"
}
while getopts ':hNu:r' flag; do
case $flag in
h)
usage
exit 0
;;
N)
unshare=1
;;
u)
userspec=$OPTARG
;;
r)
keepresolvconf=1
;;
:)
die '%s: option requires an argument -- '\''%s'\' "${0##*/}" "$OPTARG"
;;
?)
die '%s: invalid option -- '\''%s'\' "${0##*/}" "$OPTARG"
;;
esac
done
shift $(( OPTIND - 1 ))
(( $# )) || die 'No chroot directory specified'
chrootdir=$1
shift
args=("$@")
if (( unshare )); then
setup=unshare_setup
$mount_unshare bash -c "$(declare_all); arch-chroot"
else
setup=chroot_setup
arch-chroot
fi