A shell script that mounts a gocrypto volume and then auto-unmounts it when the shell exits

gocryptfs.sh

#!/bin/sh

# This script mounts an gocryptfs filesystem, starts a shell in the mounted
# directory, and then unmounts the filesystem when the shell exits.
# This is an equivalent of the cfssh utility for cfs.
# Contributed by David Rosenstrauch.

canonicalize() {
	cd "$1"
	pwd
}


if [ -z "$1" -o "$1" = "-h" ]; then
	echo Usage: gocryptfssh encrypted_directory [unencrypted-directory [-p]]
	echo "  -p   mount the unencrypted directory as public"
	exit 1
fi

enc_dir=$1
unenc_dir_given=false
mount_public=false
if [ ! -z "$2" ]; then
    unenc_dir_given=true
    unenc_dir=$2
    for arg in "$@" ; do
	if [ "$arg" = "-p" ]; then
	    mount_public=true
	fi
    done
    [ -d "$unenc_dir" ] || mkdir $unenc_dir
else
    unenc_dir=$(mktemp -d .XXXXXXXX)
fi

if [ ! -d "$enc_dir" ]; then
    mkdir $enc_dir
fi

enc_dir=$(canonicalize "$enc_dir")
unenc_dir=$(canonicalize "$unenc_dir")

options=""
if $unenc_dir_given; then
    if $mount_public; then
	options="-- -o allow_other"
    fi
fi

# Attach the directory and change into it
if gocryptfs $enc_dir $unenc_dir $options; then :; else
    echo "gocryptfs failed"
    rmdir $unenc_dir
    exit 1
fi
if ! $unenc_dir_given; then
    chmod 700 $unenc_dir
fi
echo "Directory is $unenc_dir"
orig_dir=$(pwd)
cd $unenc_dir

# Fall back to umount if fusermount is not available (e.g., on OS X)
FUSE_UMOUNT="$(which 2>/dev/null fusermount)"
FUSE_UMOUNT="${FUSE_UMOUNT:+fusermount -u}"
FUSE_UMOUNT="${FUSE_UMOUNT:-umount}"

# Set the shell up
exec /bin/sh -c "$SHELL ; cd $orig_dir ; $FUSE_UMOUNT $unenc_dir ; if ! $unenc_dir_given; then rmdir $unenc_dir; fi"