build/lib/functions/general/chroot-helpers.sh

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#!/usr/bin/env bash
#
# SPDX-License-Identifier: GPL-2.0
#
# Copyright (c) 2013-2023 Igor Pecovnik, igor@armbian.com
#
# This file is a part of the Armbian Build Framework
# https://github.com/armbian/build/
# mount_chroot <target>
function mount_chroot() {
if [[ "x${LOG_SECTION}x" == "xx" ]]; then
display_alert "mount_chroot called outside of logging section..." "mount_chroot '$1'\n$(stack_color="${magenta_color:-}" show_caller_full)" "warn"
fi
local target
target="$(realpath "$1")" # normalize, remove last slash if dir
display_alert "mount_chroot" "$target" "debug"
mkdir -p "${target}/run/user/0"
# tmpfs size=50% is the Linux default, but we need more.
mount -t tmpfs -o "size=99%" tmpfs "${target}/tmp"
mount -t tmpfs -o "size=99%" tmpfs "${target}/var/tmp"
mount -t tmpfs -o "size=99%" tmpfs "${target}/run/user/0"
mount -t proc chproc "${target}"/proc
mount -t sysfs chsys "${target}"/sys
mount --bind /dev "${target}"/dev
mount -t devpts chpts "${target}"/dev/pts || mount --bind /dev/pts "${target}"/dev/pts
}
# umount_chroot <target>
function umount_chroot() {
if [[ "x${LOG_SECTION}x" == "xx" ]]; then
display_alert "umount_chroot called outside of logging section..." "umount_chroot '$1'\n$(stack_color="${magenta_color:-}" show_caller_full)" "warn"
fi
local target
target="$(realpath "$1")" # normalize, remove last slash if dir
display_alert "Unmounting" "$target" "info"
while grep -Eq "${target}\/(dev|proc|sys|tmp|var\/tmp|run\/user\/0)" /proc/mounts; do
display_alert "Unmounting..." "target: ${target}" "debug"
umount "${target}"/dev/pts || true
umount --recursive "${target}"/dev || true
umount "${target}"/proc || true
umount "${target}"/sys || true
umount "${target}"/tmp || true
umount "${target}"/var/tmp || true
umount "${target}"/run/user/0 || true
wait_for_disk_sync "after umount chroot"
run_host_command_logged grep -E "'${target}/(dev|proc|sys|tmp)'" /proc/mounts "||" true
done
run_host_command_logged rm -rf "${target}"/run/user/0
}
# demented recursive version, for final umount. call: umount_chroot_recursive /some/dir "DESCRIPTION"
function umount_chroot_recursive() {
if [[ ! -d "${1}" ]]; then # only even try if target is a directory
return 0
fi
local target description="${2:-"UNKNOWN"}"
target="$(realpath "$1")/" # normalize, make sure to have slash as last element
if [[ ! -d "${target}" ]]; then # only even try if target is a directory
return 0 # success, nothing to do.
elif [[ "${target}" == "/" ]]; then # make sure we're not trying to umount root itself.
return 0
fi
display_alert "Unmounting recursively" "${description} - be patient" ""
wait_for_disk_sync "before recursive umount ${description}" # sync. coalesce I/O. wait for writes to flush to disk. it might take a second.
# First, try to umount some well-known dirs, in a certain order. for speed.
local -a well_known_list=("dev/pts" "dev" "proc" "sys" "boot/efi" "boot/firmware" "boot" "tmp" ".")
for well_known in "${well_known_list[@]}"; do
umount --recursive "${target}${well_known}" &> /dev/null || true # ignore errors
done
# now try in a loop to unmount all that's still mounted under the target
local -i tries=1 # the first try above
mapfile -t current_mount_list < <(cut -d " " -f 2 "/proc/mounts" | grep "^${target}" || true) # don't let grep error out.
while [[ ${#current_mount_list[@]} -gt 0 ]]; do
if [[ $tries -gt 10 ]]; then
display_alert "${#current_mount_list[@]} dirs still mounted after ${tries} tries:" "${current_mount_list[*]}" "wrn"
fi
cut -d " " -f 2 "/proc/mounts" | grep "^${target}" | xargs -n1 umount --recursive &> /dev/null || true # ignore errors
wait_for_disk_sync "during recursive umount ${description}" # sync. coalesce I/O. wait for writes to flush to disk. it might take a second.
mapfile -t current_mount_list < <(cut -d " " -f 2 "/proc/mounts" | grep "^${target}")
tries=$((tries + 1))
done
# if more than one try..
if [[ $tries -gt 1 ]]; then
display_alert "Unmounted OK after ${tries} attempt(s)" "${description}" "info"
fi
return 0
}