240 lines
6.9 KiB
Bash
240 lines
6.9 KiB
Bash
#!/bin/sh -e
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# (C) 2008 Canonical Ltd.
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# Author: Martin Pitt <martin.pitt@ubuntu.com>
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# License: GPL v2 or later
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# modified by David D Lowe and Thomas Detoux
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#
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# Setup user and temporary home directory for guest session.
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# If this succeeds, this script needs to print the username as the last line to
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# stdout.
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# github.com/CanonicalLtd/lightdm
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# debian/guest-account.sh
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export TEXTDOMAINDIR=/usr/share/locale-langpack
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export TEXTDOMAIN=lightdm
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# set the system wide locale for gettext calls
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if [ -f /etc/default/locale ]; then
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. /etc/default/locale
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LANGUAGE=
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export LANG LANGUAGE
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fi
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# read list of supplementary groups of the guest account from file
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if [ -f /etc/guest-account/groups ]; then
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GROUPS="$(awk '{ if (NR==1) printf "%s", $0; else printf ",%s", $0; } END { print "" }' /etc/guest-account/groups)"
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fi
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is_system_user ()
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{
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UID_MIN=$(cat /etc/login.defs | grep UID_MIN | awk '{print $2}')
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SYS_UID_MIN=$(cat /etc/login.defs | grep SYS_UID_MIN | awk '{print $2}')
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SYS_UID_MAX=$(cat /etc/login.defs | grep SYS_UID_MAX | awk '{print $2}')
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SYS_UID_MIN=${SYS_UID_MIN:-101}
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SYS_UID_MAX=${SYS_UID_MAX:-$(( UID_MIN - 1 ))}
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[ ${1} -ge ${SYS_UID_MIN} ] && [ ${1} -le ${SYS_UID_MAX} ]
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}
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add_account ()
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{
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temp_home=$(mktemp -td guest-XXXXXX)
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GUEST_HOME=$(echo ${temp_home} | tr '[:upper:]' '[:lower:]')
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GUEST_USER=${GUEST_HOME#/tmp/}
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if [ "${GUEST_HOME}" != "${temp_home}" ]; then
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mkdir -m 700 "${GUEST_HOME}" || {
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echo "Failed to create ${GUEST_USER}'s home directory (${GUEST_HOME})"
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exit 1
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}
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rmdir "${temp_home}"
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fi
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if [ "${GROUPS}" != "" ]; then
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GROUPS="--groups ${GROUPS}"
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fi
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# if ${GUEST_USER} already exists, it must be a locked system account with no existing
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# home directory
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if PWSTAT=$(passwd -S ${GUEST_USER}) 2>/dev/null; then
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if [ $(echo ${PWSTAT} | cut -f2 -d' ') != L ]; then
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echo "User account ${GUEST_USER} already exists and is not locked"
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exit 1
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fi
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PWENT=$(getent passwd ${GUEST_USER}) || {
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echo "getent passwd ${GUEST_USER} failed"
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exit 1
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}
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GUEST_UID=$(echo ${PWENT} | cut -f3 -d:)
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if ! is_system_user ${GUEST_UID}; then
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echo "Account ${GUEST_USER} is not a system user"
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exit 1
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fi
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GUEST_HOME=$(echo ${PWENT} | cut -f6 -d:)
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if [ ${GUEST_HOME} != / ] && [ ${GUEST_HOME#/tmp} = ${GUEST_HOME} ] && [ -d ${GUEST_HOME} ]; then
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echo "Home directory of ${GUEST_USER} already exists"
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exit 1
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fi
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else
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# does not exist, so create it
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useradd --system --home-dir ${GUEST_HOME} --comment $(gettext "Guest") --user-group --shell /bin/bash ${GROUPS} ${GUEST_USER} || {
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rm -rf ${GUEST_HOME}
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exit 1
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}
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fi
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dist_gs=/usr/share/lightdm/guest-session
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site_gs=/etc/guest-session
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# create temporary home directory
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mount -t tmpfs -o mode=700,uid=${GUEST_USER} none ${GUEST_HOME} || {
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rm -rf ${GUEST_HOME}
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exit 1
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}
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if [ -d ${site_gs}/skel ] && [ "$(ls -A ${site_gs}/skel)" ]; then
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# Only perform union-mounting if BindFS is available
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if [ -x /usr/bin/bindfs ]; then
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bindfs_mount=true
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# Try OverlayFS first
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if modinfo -n overlay >/dev/null 2>&1; then
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mkdir ${GUEST_HOME}/upper ${GUEST_HOME}/work
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chown ${GUEST_USER}:${GUEST_USER} ${GUEST_HOME}/upper ${GUEST_HOME}/work
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mount -t overlay -o lowerdir=${dist_gs}/skel:${site_gs}/skel,upperdir=${GUEST_HOME}/upper,workdir=${GUEST_HOME}/work overlay ${GUEST_HOME} || {
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umount ${GUEST_HOME}
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rm -rf ${GUEST_HOME}
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exit 1
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}
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# If OverlayFS is not available, try AuFS
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elif [ -x /sbin/mount.aufs ]; then
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mount -t aufs -o br=${GUEST_HOME}:${dist_gs}/skel:${site_gs}/skel none ${GUEST_HOME} || {
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umount ${GUEST_HOME}
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rm -rf ${GUEST_HOME}
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exit 1
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}
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# If none of them is available, fall back to copy over
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else
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cp -rT ${site_gs}/skel/ ${GUEST_HOME}
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cp -rT ${dist_gs}/skel/ ${GUEST_HOME}
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chown -R ${GUEST_USER}:${GUEST_USER} ${GUEST_HOME}
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bindfs_mount=false
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fi
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if ${bindfs_mount}; then
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# Wrap ${GUEST_HOME} in a BindFS mount, so that
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# ${GUEST_USER} will be seen as the owner of ${GUEST_HOME}'s contents.
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bindfs -u ${GUEST_USER} -g ${GUEST_USER} ${GUEST_HOME} ${GUEST_HOME} || {
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umount ${GUEST_HOME} # union mount
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umount ${GUEST_HOME} # tmpfs mount
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rm -rf ${GUEST_HOME}
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exit 1
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}
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fi
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# If BindFS is not available, just fall back to copy over
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else
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cp -rT ${site_gs}/skel/ ${GUEST_HOME}
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cp -rT ${dist_gs}/skel/ ${GUEST_HOME}
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chown -R ${GUEST_USER}:${GUEST_USER} ${GUEST_HOME}
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fi
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else
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cp -rT /etc/skel/ ${GUEST_HOME}
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cp -rT ${dist_gs}/skel/ ${GUEST_HOME}
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chown -R ${GUEST_USER}:${GUEST_USER} ${GUEST_HOME}
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fi
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# setup session
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su ${GUEST_USER} -c "env HOME=${GUEST_HOME} site_gs=${site_gs} ${dist_gs}/setup.sh"
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# set possible local guest session preferences
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source_local_prefs() {
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local USER=${GUEST_USER}
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local HOME=${GUEST_HOME}
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. ${site_gs}/prefs.sh
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chown -R ${USER}:${USER} ${HOME}
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}
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if [ -f ${site_gs}/prefs.sh ]; then
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source_local_prefs
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fi
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echo ${GUEST_USER}
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}
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remove_account ()
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{
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GUEST_USER=${1}
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PWENT=$(getent passwd ${GUEST_USER}) || {
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echo "Error: invalid user ${GUEST_USER}"
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exit 1
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}
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GUEST_UID=$(echo ${PWENT} | cut -f3 -d:)
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if ! is_system_user ${GUEST_UID}; then
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echo "Error: user ${GUEST_USER} is not a system user."
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exit 1
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fi
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GUEST_HOME=$(echo ${PWENT} | cut -f6 -d:)
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# kill all remaining processes
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if [ -x /bin/loginctl ] || [ -x /usr/bin/loginctl ]; then
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loginctl --signal=9 kill-user ${GUEST_USER} >/dev/null || true
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else
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while ps h -u ${GUEST_USER} >/dev/null
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do
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killall -9 -u ${GUEST_USER} || true
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sleep 0.2;
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done
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fi
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if [ ${GUEST_HOME} = ${GUEST_HOME#/tmp/} ]; then
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echo "Warning: home directory ${GUEST_HOME} is not in /tmp/. It won't be removed."
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else
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umount ${GUEST_HOME} || umount -l ${GUEST_HOME} || true # BindFS mount
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umount ${GUEST_HOME} || umount -l ${GUEST_HOME} || true # union mount
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umount ${GUEST_HOME} || umount -l ${GUEST_HOME} || true # tmpfs mount
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rm -rf ${GUEST_HOME}
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fi
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# remove leftovers in /tmp
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find /tmp -mindepth 1 -maxdepth 1 -uid ${GUEST_UID} -print0 | xargs -0 rm -rf || true
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# remove possible {/run,}/media/guest-XXXXXX folder
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for media_dir in /run/media/${GUEST_USER} /media/${GUEST_USER}; do
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if [ -d ${media_dir} ]; then
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for dir in $(find ${media_dir} -mindepth 1 -maxdepth 1); do
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umount ${dir} || true
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done
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rmdir ${media_dir} || true
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fi
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done
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userdel --force ${GUEST_USER}
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}
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case ${1} in
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add)
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add_account
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;;
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remove)
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if [ -z ${2} ] ; then
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echo "Usage: ${0} remove [account]"
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exit 1
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fi
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remove_account ${2}
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;;
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*)
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echo "Usage: ${0} add"
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echo " ${0} remove [account]"
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exit 1
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esac
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