csdir

#!/bin/bash
#
# csdir (create shared directory)
#
# creates a directory with proper permissions for sharing files between
# local users and creates symbolic links on every user's desktop
#
# -> check out the CONFIG section, adapt it to fit your needs!
#
# Copyright 2014 Thorsten Hirsch
# License: GPL v3 (for details see LICENSE)
#
# History: (entry on top == current version)
# 20140731 initial version

### CONFIG START ###
SHARED_DIR="/home/shared"
SHARED_GROUP="users"
LINK_SUBDIR=$(basename $(xdg-user-dir DESKTOP)) # default: Desktop
LINK_NAME="shared"
XDG_FOLDERS="DOWNLOAD TEMPLATES PUBLICSHARE DOCUMENTS MUSIC PICTURES VIDEOS"
USER_HOMES=$(find /home -maxdepth 1 -group ${SHARED_GROUP} -type d)
### CONFIG END ####

main()
{
    check_args "$@"
    check_sudo
    check_shared_dir
    check_doit "$@"
    create_shared_dir
    set_permissions
    create_links
    echo "finished."

    exit 0
}

### SUB FUNCTIONS ###

check_args()
{
    if [ "$1" != "check" ] && [ "$1" != "do-it" ]; then
        cat <<_EOF_
usage: sudo $0 check|do-it

    check   check prerequisites
    do-it   does the following tasks:
            - creates new directory ${SHARED_DIR}
            - sets acl permissions: group-writable for ${SHARED_GROUP}
            - creates symlinks for each user of that group

_EOF_
        exit 1
    fi
}

check_doit()
{
    if [ "$1" != "do-it" ]; then
        echo "check successful. you can do-it!"
        exit 0
    fi
}

check_sudo()
{
    if [ -z ${SUDO_USER} ]; then
        echo "must be run with sudo"
        exit 2
    fi
}

check_shared_dir()
{
    unset ACLFOUND
    MOUNT_POINT=$(df -P $(dirname ${SHARED_DIR}) | tail -1 | cut -d' ' -f 1)
    MOUNT_OPTIONS=$(mount | grep ^"${MOUNT_POINT} " | sed 's/.*(\(.*\))$/\1/')
    IFS=","
    for i in ${MOUNT_OPTIONS}; do
        if [ "$i" == "acl" ]; then ACLFOUND=TRUE; fi
    done
    unset IFS
    if [ -z ${ACLFOUND} ]; then 
        echo "need a filesystem with acl"
        exit 3
    fi
}

create_shared_dir()
{
    echo -n "creating shared directory... "
    [[ ! -e ${SHARED_DIR} ]] && mkdir ${SHARED_DIR} && echo "OK" || echo "SKIPPED"
    for i in ${XDG_FOLDERS}; do
        NAME=$(basename $(xdg-user-dir ${i}))
        echo -n "- ${NAME} "
        [[ ! -e ${SHARED_DIR}/${NAME} ]] && mkdir ${SHARED_DIR}/${NAME} && echo "OK" || echo "SKIPPED"
    done
}

set_permissions()
{
    echo -n "setting permissions... "
    chgrp -R ${SHARED_GROUP} ${SHARED_DIR} && echo -n "OK" || echo -n "ERROR"
    chmod -R g+ws ${SHARED_DIR} && echo -n "/OK" || echo -n "/ERROR"
    setfacl -R -d -m g:${SHARED_GROUP}:rw ${SHARED_DIR} && echo "/OK" || echo "/ERROR"
}

create_links()
{
    echo "creating links for users..."
    for i in ${USER_HOMES}; do
        LINK=${i}
        [[ -n ${LINK_SUBDIR} ]] && LINK="${LINK}/${LINK_SUBDIR}"
        LINK="${LINK}/${LINK_NAME}"
        echo -n "- ${LINK} "
        [[ ! -e ${LINK} ]] && [[ ! -L ${LINK} ]] && ln -s ${SHARED_DIR} ${LINK} && echo "OK" || echo "SKIPPED"
    done
}

# function definitions must precede their usage, which is a real pitty,
# but we can workaround that issue by putting everything in a main function

main "$@"

# END