ps-mount

#!/bin/bash -e

# Weird things can happen if some output goes to console
exec 1>/dev/null 2>&1


# Fork in order not to stall udev on this and related devices
if [ fork != "$1" ]; then
    # Use of auto.media is exclusive via file lock
    lock=/var/lock/ps-mount.lock
    (flock 20; "$0" fork "$@") 20>>${lock} &
else
    shift

    # Files and scripts
    prefix=/media
    autofspid=/var/run/autofs.pid

    mountsorg=/etc/autofs/auto.media
    mounts=/var/run/auto.media

    # Mount options (permissions: rw------- / rwx------)
    supported=" ext2 ext3 ext4 vfat msdos exfat ntfs ntfs-3g iso9660 udf hfs hfsplus vmhgfs vboxsf "
    luser=anon
    lgroup=legion
    opts_common=noatime,nosuid,nodev,noexec
    opts_vfat=${opts_common},flush,iocharset=iso8859-1,utf8,showexec,uid=${luser},gid=${lgroup},umask=0177,dmask=077
    opts_exfat=${opts_common},uid=${luser},gid=${lgroup},umask=0177,dmask=077
    opts_ntfs=${opts_common},compression,uid=${luser},gid=${lgroup},fmask=0177,dmask=077
    opts_ntfs_ro=${opts_common},ro,compression,uid=${luser},gid=${lgroup},fmask=0377,dmask=0277
    opts_iso9660=${opts_common},ro,iocharset=iso8859-1,utf8,uid=${luser},gid=${lgroup},mode=0400,dmode=0500
    opts_udf=${opts_common},unhide,undelete,iocharset=iso8859-1,uid=${luser},uid=ignore,uid=forget,gid=${lgroup},gid=ignore,gid=forget,umask=077
    opts_ext2=${opts_common},acl,user_xattr
    opts_ext3=${opts_ext2}
    opts_ext4=${opts_ext2}
    opts_hfs=${opts_common},uid=${luser},gid=${lgroup},file_umask=0177,dir_umask=077
    opts_hfsplus=${opts_common},ro,uid=${luser},gid=${lgroup},umask=0277
    opts_vmhgfs=${opts_common},uid=${luser},gid=${lgroup},fmask=0177,dmask=077
    opts_vboxsf=nosuid,nodev,noexec,uid=${luser},gid=${lgroup},umask=0177,dmask=077
    opts_auto=${opts_vfat}

    # Ensure that ${mounts} exists
    if [ ! -e ${mounts} ]; then
        cp ${mountsorg} ${mounts}
    fi

    # Checking whether device is in fstab (except root fs), or is mounted
    DEVLINKS=" ${DEVLINKS} "
    fstab_check() {
        if [ -n "${FSTAB_NAME}" ]; then
            echo fstab
        else
            local rootdevs=`awk '/^\// { print $1 }' /etc/fstab`
            local mdev

            for mdev in ${rootdevs}; do
                if [ ${mdev} = "${DEVNAME}" -o -z "${DEVLINKS/* ${mdev} */}" ]; then
                    echo fstab
                    return
                fi
            done

            # /proc/mounts contains only device names
            # (no UUID or LABEL, but may contain symlinks)
            rootdevs=`awk '/^\// { print $1 }' /proc/mounts`

            for mdev in ${rootdevs}; do
                if [ ${mdev} = "${DEVNAME}" -o -z "${DEVLINKS/* ${mdev} */}" ]; then
                    echo mtab
                    return
                fi
            done

            echo none
        fi
    }

    # Nothing to do if the device is handled by fstab
    fscheck=`fstab_check`
    if [ "${fscheck}" = fstab ]; then
        exit
    fi

    # Exit if fs type is available, but is not supported
    if [ -n "${ID_FS_TYPE}" -a -n "${supported/* ${ID_FS_TYPE} */}" ]; then
        exit
    fi

    # Assign volume label if unavailable
    if [ -z "${ID_FS_LABEL}" ]; then
        if [ -n "${ID_MODEL}" ]; then
            ID_FS_LABEL="${ID_VENDOR:+${ID_VENDOR/%/_}}${ID_MODEL}"
        elif [ "${DEVNAME/[0-9]/X}" = /dev/fdX ]; then
            ID_FS_LABEL="floppy${DEVNAME/\/dev\/fd/}"
            ID_FS_LABEL="${ID_FS_LABEL/floppy0/floppy}"
        elif [ "${ID_CDROM}" = 1 ]; then
            ID_FS_LABEL="cdrom"
            if [ "${ID_CDROM_DVD}" = 1 ]; then
                ID_FS_LABEL="dvdrom"
            fi
        elif env | grep -q '^ID_CDROM_MEDIA_CD.*=1$'; then
            ID_FS_LABEL=unnamed-cd
        elif env | grep -q '^ID_CDROM_MEDIA_DVD.*=1$'; then
            ID_FS_LABEL=unnamed-dvd
        else
            ID_FS_LABEL=unnamed-disk
        fi
    fi

    # Get current autofs devices and keys (space-separated)
    autodevs=`awk '/^[^#]/ { printf " " substr($3, 2) }' ${mounts}; echo -n ' '`
    autokeys=`awk '/^[^#]/ { printf " " substr($1,2,length($1)-2) }' ${mounts}; echo -n ' '`

    # Fixing volume label in case of collision
    fixlabel() {
        if [ -z "${autokeys/* ${ID_FS_LABEL} */}" ]; then
            local suffix=2

            while [ -z "${autokeys/* ${ID_FS_LABEL}-${suffix} */}" ]; do
                let suffix=suffix+1
            done

            ID_FS_LABEL="${ID_FS_LABEL}-${suffix}"
        fi
    }

    # Reloading autofs if it is running
    reload_autofs() {
        if [ -r ${autofspid} ]; then
            kill -HUP `cat ${autofspid}`
        fi
    }

    # Adding new auto.media entry
    # (also update autokeys)
    add_entry() {
        case "${ID_FS_TYPE}" in
            auto|ext2|ext3|ext4|vfat|exfat|iso9660|udf|hfs|hfsplus|vmhgfs|vboxsf)
                eval type=${ID_FS_TYPE},\${opts_${ID_FS_TYPE}}
                ;;
            msdos)
                type="vfat,${opts_vfat}"
                ;;
            ntfs|ntfs-3g)
                type="ntfs-3g,${opts_ntfs}"

                # Possibly make mount point read-only for NTFS (e.g., hibernated Windows)
                if ! ntfs-3g.probe -w "${DEVNAME}"; then
                    type="ntfs-3g,${opts_ntfs_ro}"
                fi
                ;;
            *)
                # Fallback, shouldn't happen
                logger -p 4 -t auto.media "unknown filesystem type: ${ID_FS_TYPE}"
                return
                ;;
        esac

        fixlabel
        echo "\"${ID_FS_LABEL}\" -fstype=${type} :${DEVNAME}" >> ${mounts}
        autokeys="${autokeys}${ID_FS_LABEL} "
    }

    # Unmount and remove existing auto.media entry (or entries)
    # (also update autokeys for fixlabel after ACTION=change)
    remove_entry() {
        # Unmount mount points, not devices (since there can be several per device)
        local keys=`awk '/^[^#]/ && $3 == ":'"${DEVNAME}"'" { print substr($1,2,length($1)-2) }' ${mounts}`
        local key
        local kl="$1"

        for key in ${keys}; do
            # NOTE: lazy unmount
            umount -l ${prefix}/"${key}" 2>/dev/null || :
            autokeys="${autokeys/ ${key} / }"

            if [ "${kl}" = keeplabel ]; then
                ID_FS_LABEL="${key}"
                kl=
            fi
        done

        # Remove entries (will be removed from dir after autofs reload)
        sed -i "\&^[^#].* :${DEVNAME}"'$&d' ${mounts}
    }

    # For "add" action, a line is added only for non-existing (in autofs or mounted) device
    if [ "${ACTION}" = add ]; then
        if [ -n "${autodevs/* ${DEVNAME} */}" -a "${fscheck}" != mtab ]; then
            # Generate fs type for static floppy/cd directories
            if [ "${DEVNAME/[0-9]/X}" = /dev/fdX ]; then
                ID_FS_TYPE=auto
            elif [ "${ID_CDROM}" = 1 ]; then
                ID_FS_TYPE=iso9660
            fi

            # Add an entry only if fs type is available
            if [ -n "${ID_FS_TYPE}" ]; then
                add_entry
                reload_autofs
            fi
        fi
    # For "change" action (non-fuse-generated), a line is replaced,
    # but label is not changed
    elif [ "${ACTION}" = change -a \( "${DISK_MEDIA_CHANGE}" = 1 -o -n "${DM_NAME}" \) ]; then
        # Update if present in autofs or is a non-existing device, and is a filesystem
        if [ \( -z "${autodevs/* ${DEVNAME} */}" -o "${fscheck}" != mtab \) -a -n "${ID_FS_TYPE}" ]; then
            remove_entry keeplabel
            add_entry
            reload_autofs
        fi
    # For "remove" action, the line corresponding to the device is removed
    elif [ "${ACTION}" = remove ]; then
        if [ -z "${autodevs/* ${DEVNAME} */}" ]; then
            remove_entry
            reload_autofs
        fi
    fi
fi