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# -----------------------------------------------------------------------------
#
# Copyright (c) 2014 - OpenSLX GmbH
#
# This program is free software distributed under the GPL version 2.
# See http://openslx.org/COPYING
#
# If you have any feedback please consult http://openslx.org/feedback and
# send your suggestions, praise, or complaints to feedback@openslx.org
#
# General information about OpenSLX can be found at http://openslx.org/
# -----------------------------------------------------------------------------
#
# Common functions for chrooting
#
# -----------------------------------------------------------------------------
declare -rg CHROOT_TEMPDIR="${ROOT_DIR}/remote/chroot.tmp"
declare -rg CHROOT_MOUNTDIR="${CHROOT_TEMPDIR}/rootmount"
declare -rg CHROOT_BINDDIR="${CHROOT_TEMPDIR}/rootbind"
declare -rg CHROOT_LOWERDIR="/"
declare -rg CHROOT_BINDMOUNTS="/dev /proc /sys /run"
# Helper function to setup the directory structure
chroot_prepare_dirs() {
# first check if CHROOT_TEMPDIR exists
if [ -d "${CHROOT_TEMPDIR}" ]; then
# try to umount and rmdir CHROOT_MOUNTDIR
umount "${CHROOT_MOUNTDIR}" 2>/dev/null
rmdir "${CHROOT_MOUNTDIR}" || perror "Could not remove '${CHROOT_MOUNTDIR}', meaning it has stuff in it. Aborting..."
# try to umount and rmdir CHROOT_BINDDIR
umount "${CHROOT_BINDDIR}" 2>/dev/null
rmdir "${CHROOT_BINDDIR}" || perror "Could not remove '${CHROOT_BINDDIR}', meaning it has stuff in it. Aborting..."
# try to rmdir CHROOT_TEMPDIR
rmdir "${CHROOT_TEMPDIR}" || perror "Could not remove '${CHROOT_TEMPDIR}', meaning it has stuff in it. Aborting..."
fi
mkdir -p "${CHROOT_TEMPDIR}" || perror "Could not create base directory for mount directories $CHROOT_TEMPDIR."
for DIR in "${CHROOT_BINDDIR}" "${CHROOT_MOUNTDIR}"; do
mkdir -p "${DIR}" || perror "Could not create directory for mount directory $DIR."
done
}
# Helper to mount the overlay structure:
# - bind mount system / to CHROOT_BINDDIR and make it read-only
# - make an overlay from CHROOT_LOWERDIR CHROOT_UPPERDIR
# - bind mount additional pseudo-fs (as given in CHROOT_BINDMOUNTS)
chroot_prepare_mounts() {
# first mount / on CHROOT_BINDDIR and remount read-only
mount -o bind "${CHROOT_LOWERDIR}" "${CHROOT_BINDDIR}" || perror "Could not bind-mount '$CHROOT_LOWERDIR' to '$CHROOT_BINDDIR'."
mount -o remount,ro,bind "${CHROOT_BINDDIR}" || perror "Could not remount '$CHROOT_BINDDIR' read-only."
# check that it really is read-only
[ "x$(mount | grep -E "^/ on ${CHROOT_BINDDIR}" | grep -v '\(.*ro.*\)')" != "x" ] && perror "'${CHROOT_BINDDIR}' is not read-only! Aborting..."
# safe, go on to make the overlay
mount -t overlayfs overlayfs -o lowerdir="${CHROOT_BINDDIR}",upperdir="${CHROOT_UPPERDIR}" "${CHROOT_MOUNTDIR}" \
|| perror "Could not mount (overlayfs) $CHROOT_LOWERDIR, $CHROOT_UPPERDIR to $CHROOT_BINDDIR."
# mount pseudo-filesystems
for DIR in $CHROOT_BINDMOUNTS; do
mount -o bind "${DIR}" "${CHROOT_MOUNTDIR}/${DIR}" \
|| perror "Could not bind mount '$DIR' into '$CHROOT_MOUNTDIR/$DIR'."
done
}
# Helper to generate the mighty autoexec.bat
chroot_gen_autoexec() {
# create the script to be automatically executed.
cat >"${CHROOT_MOUNTDIR}/autoexec.bat"<<-EOF
#!/bin/bash
#######################################################
# #
# Warning! #
# #
# This file is only meant to be executed within #
# the specially chrooted mltk building environment. #
# #
# Do NOT execute it if you are not sure what you do, #
# it may be very harmful if being run in a normal #
# system environment! #
# #
#######################################################
echo "chroot started successfully."
EOF
# dump the piped input to it
cat >> "${CHROOT_MOUNTDIR}/autoexec.bat"
# make it executable
chmod +x "${CHROOT_MOUNTDIR}/autoexec.bat" || perror "Failed to make '${CHROOT_MOUNTDIR}/autoexec.bat' exeutable."
}
chroot_handle_whiteouts() {
local WHITEOUT_LIST="${CHROOT_UPPERDIR}/overlay.whiteout.list"
rm -f -- "$WHITEOUT_LIST="
#mkdir -p "$(dirname "$WHITEOUT_LIST")" || perror "Could not create $(dirname "$WHITEOUT_LIST")"
pdebug "Searching for overlayfs-whiteouts ..."
for WHITEOUT in $(find "$CHROOT_UPPERDIR" -lname "(overlay-whiteout)"); do
pdebug "Whiteout found: $WHITEOUT"
echo "/./${WHITEOUT#$CHROOT_UPPERDIR}" >> "$WHITEOUT_LIST"
rm -f -- "$WHITEOUT" || perror "Could not delete whiteout $WHITEOUT!"
done
pinfo "Whiteout list dumped to '${CHROOT_UPPERDIR}/overlay.whiteout.list'"
}
###############################################################################
#
# MAIN FUNCTION
#
# Main function to be called from the outside
# Usage:
# chroot_run <build_dir> < <code_to_exec_in_chroot>
#
# Example:
# chroot_run /tmp/chroot_build <<-EOF
# echo "This will be executed inside the chroot"
# EOF
#
# It will run:
# - chroot_prepare
# - chroot $CHROOT_TEMPDIR/rootmount
# - executes $CHROOT_TEMPDIR/rootmount/autoexec.bat
# - chroot_cleanup
chroot_run() {
# check args
[ $# -eq 1 ] || perror "'chroot_run' requires exactly 1 parameter. Given $#. Use 'chroot_run <build_dir>'"
local CHROOT_UPPERDIR="$1"
mkdir -p "$1"
# first prepare the dir structure
chroot_prepare_dirs || perror "'chroot_prepare_dirs' failed with $?."
chroot_prepare_mounts || perror "'chroot_prepare_mounts' failed with $?."
# generate the code to be executed when chroot'ing
chroot_gen_autoexec || perror "'chroot_gen_autoexec' failed with $?."
# do the chroot
exec 0>&8 # This redirection is used for debugging within a chroot
chroot --userspec root:root "${CHROOT_MOUNTDIR}" /autoexec.bat
local RET=$?
if [ "$RET" -eq 0 ]; then
pinfo "chroot executed '${CHROOT_MOUNTDIR}/autoexec.bat' succeeded."
else
perror "Failed to run '$CHROOT_MOUNTDIR/autoexec.bat' inside the chroot to '$CHROOT_MOUNTDIR' with error code: $RET"
fi
# handle whiteouts
chroot_handle_whiteouts || perror "'chroot_handle_whiteouts' failed with error code: $?"
# finally cleanup all the mounting stuff we did previously
chroot_cleanup_mounts || perror "'chroot_cleanup' failed with $?."
}
###############################################################################
#
# CLEANUP FUNCTIONS
#
# Helper to check if the given path is mounted
chroot_check_mount_point() {
[ "$#" -eq 1 ] || perror "'chroot_check_mount_point' called with $# arguements, only 1 accepted."
local MOUNT="$1"
if [ "x$(mount | grep "$(readlink -f $MOUNT)")" != "x" ]; then
# still mounted
pdebug "'$MOUNT' is mounted!"
return 1
else
pdebug "'$MOUNT' is not mounted."
return 0
fi
}
# Helper to umount the given path
chroot_umount() {
[ "$#" -eq 1 ] || perror "'chroot_umount' called with $# arguments, only 1 accepted."
local MOUNT="$1"
# check if MOUNT is mounted
if ! chroot_check_mount_point "${MOUNT}"; then
# still mounted
if umount -l "${MOUNT}"; then
pdebug "Successfully umounted '${MOUNT}'."
else
pwarning "Could not umount '${MOUNT}'! Trying again..."
# now it gets ugly
for i in `seq 1 5`; do
umount -l "${MOUNT}" && return 0
done
perror "Could not umount '${MOUNT}' after 5 tries! This shouldn't happen. Check your scripts."
fi
else
pdebug "'${MOUNT}' is not mounted."
fi
# better be safe than sorry
chroot_check_mount_point "$MOUNT" || perror "'$MOUNT' is still mounted, exiting before something bad happens..."
}
# Helper to cleanup the temporary mounts
chroot_cleanup_mounts() {
if [[ "$(mount | grep -c $CHROOT_TEMPDIR)" -gt 0 ]]; then # No point in unmounting then...
for DIR in $CHROOT_BINDMOUNTS; do
chroot_umount "${CHROOT_MOUNTDIR}/${DIR}"
done
chroot_umount "${CHROOT_MOUNTDIR}"
chroot_umount "${CHROOT_BINDDIR}"
else
pinfo "Nothing chroot-related is mounted - exiting."
fi
}
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