#!/bin/sh

# copyright 2009 Vagrant Cascadian <vagrant@freegeek.org>,
# 2010 Alkis Georgopoulos <alkisg@gmail.com>,
# 2011 Wim Muskee <wimmuskee@gmail.com>, distributed under the
# terms of the GNU General Public License version 2 or any later version.

# generic functions

usage() {
cat <<EOF
Usage: $0 [OPTION] command

Chroots into a specified LTSP chroot. Optional arguments can be provided to customize
the chroot location as well as extra mounts. If present, default arguments will be read
from the configuration file /etc/ltsp/ltsp-chroot.conf, and overwritten with used
command line options.

Options:
  -a, --arch[=ARCH]             Sets the architecture of the target chroot. Defaults vary by distribution.
  -b, --base[=PATH]             Sets base of target chroot. Defaults to /opt/ltsp if unspecified.
  -c, --mount-package-cache     If set, mounts the server package directories to the chroot previous
                                to chrooting. Settings vary by distribution.
  -d, --mount-dev               If set, mounts the server dev and devpts directories to the chroot
                                previous to chrooting.
  -h, --help                    Displays the ltsp-chroot help message.
  -p, --mount-proc              If set, mounts the server /proc to the chroot previous to chrooting.
  -m, --mount-all               If set, mounts the /proc, /dev and package directories to the chroot
                                before chrooting.
  -r, --copy-resolv-conf        If set, copies the server resolv.conf to the chroot previous to chrooting.
      --version                 Output version information and exit.
EOF
}

default_options() {
    if [ -n "$ROOT" ]; then
        # If $ROOT contains a terminating /, remove it
        ROOT=${ROOT%/}
        # Extract $BASE and $ARCH from $ROOT in case they're needed afterwards
        BASE=${ROOT%/*}
        ARCH=${ROOT##*/}
    else
        BASE=${BASE:-/opt/ltsp}
        # If $BASE contains a terminating /, remove it
        BASE=${BASE%/}
        if [ -z "$ARCH" ]; then
            # Prefer the chroot that corresponds to the server arch,
            # but if that doesn't exist, use the first one available.
            ARCH=$(detect_arch)

            if [ ! -d "$BASE/$ARCH" ]; then
                for ARCH in $(list_chroots nfs); do
                    test -x "$BASE/$ARCH/bin/true" && break
                done
            fi
        fi
        ROOT="$BASE/$ARCH"
    fi
}

pre_chroot() {
    test -d "$ROOT" || die "ERROR: ltsp chroot not found: $ROOT"

    if boolean_is_true "$MOUNT_ALL"; then
        MOUNT_PACKAGE_CACHE=true
        MOUNT_DEV=true
        MOUNT_PROC=true
    fi
    if boolean_is_true "$MOUNT_PACKAGE_CACHE"; then
        mount_package_cache
    fi
    if boolean_is_true "$MOUNT_DEV"; then
        mark_mount --bind "/dev" "$ROOT/dev"
        mark_mount -t devpts -o rw,noexec,nosuid,gid=5,mode=620 devpts "$ROOT/dev/pts"
    fi
    if boolean_is_true "$MOUNT_PROC"; then
        mark_mount -t proc proc "$ROOT/proc"
    fi
    if boolean_is_true "$COPY_RESOLV_CONF"; then
        cp /etc/resolv.conf "$ROOT/etc/"
    fi
}

post_chroot() {
    # Stop trapping
    trap - 0 HUP INT QUIT KILL SEGV PIPE TERM
    umount_marked
}

# distro specific functions
mount_package_cache() {
    echo "Mounting the package cache is not available for your distribution."
}

# Set an optional MODULES_BASE, so help2man can be called from build env
MODULES_BASE=${MODULES_BASE:-/usr/share/ltsp}

# This also sources vendor functions and .conf file settings
. ${MODULES_BASE}/ltsp-server-functions

# The command line parameters override the configuration file settings
if ! args=$(getopt -n "$0" -o +a:b:cdhmpr -l \
    'arch:,base:,mount-package-cache,mount-dev,help,mount-all,mount-proc,copy-resolv-conf,version' -- "$@"); then
    exit 1
fi
eval "set -- $args"
while true; do
    case "$1" in
        -a|--arch) shift; ARCH=$1 ;;
        -b|--base) shift; BASE=$1 ;;
        -c|--mount-package-cache) MOUNT_PACKAGE_CACHE=true ;;
        -d|--mount-dev) MOUNT_DEV=true ;;
        -h|--help) usage; exit 0 ;;
        -m|--mount-all) MOUNT_ALL=true ;;
        -p|--mount-proc) MOUNT_PROC=true ;;
        -r|--copy-resolv-conf) COPY_RESOLV_CONF=true ;;
        --version) ltsp_version; exit 0 ;;
        --) shift; break ;;
        *) die "$0: Internal error!" ;;
    esac
    shift
done

# Finally, fall back to using default values for any unset options
default_options

require_root

trap "post_chroot" 0 HUP INT QUIT KILL SEGV PIPE TERM
pre_chroot

# Unset temporary directory variables to avoid problems when directory
# is missing inside the chroot. https://bugs.debian.org/765443
unset TMPDIR TEMP TEMPDIR TMP

LTSP_HANDLE_DAEMONS=false chroot "$ROOT" "$@"