distrobox-export

#!/bin/sh
# SPDX-License-Identifier: GPL-3.0-only
#
# This file is part of the distrobox project:
#    https://github.com/89luca89/distrobox
#
# Copyright (C) 2021 distrobox contributors
#
# distrobox is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License version 3
# as published by the Free Software Foundation.
#
# distrobox is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with distrobox; if not, see <http://www.gnu.org/licenses/>.

# POSIX
# Expected env variables:
#	HOME
#	USER
#	DISTROBOX_ENTER_PATH
#	DISTROBOX_HOST_HOME

# Defaults
export_action=""
exported_app=""
exported_app_label=""
exported_bin=""
exported_delete=0
extra_flags=""
# Use DBX_HOST_HOME if defined, else fallback to HOME
#	DBX_HOST_HOME is set in case container is created
#	with custom --home directory
host_home="${DISTROBOX_HOST_HOME:-"${HOME}"}"
dest_path="${host_home}/.local/bin"
is_login=0
is_sudo=0
rootful=""
start_shell=""
verbose=0
version="1.5.0.2"

# We depend on some commands, let's be sure we have them
base_dependencies="basename find grep sed"
for dep in ${base_dependencies}; do
	if ! command -v "${dep}" > /dev/null; then
		printf >&2 "Missing dependency: %s\n" "${dep}"
		exit 127
	fi
done

# Print usage to stdout.
# Arguments:
#   None
# Outputs:
#   print usage with examples.
show_help() {
	cat << EOF
distrobox version: ${version}

Usage:

	distrobox-export --app mpv [--extra-flags "flags"] [--delete] [--sudo]
	distrobox-export --bin /path/to/bin [--export-path ~/.local/bin] [--extra-flags "flags"] [--delete] [--sudo]

Options:

	--app/-a:		name of the application to export
	--bin/-b:		absolute path of the binary to export
	--delete/-d:		delete exported application or binary
	--export-label/-el:	label to add to exported application name.
				Defaults to (on \$container_name)
	--export-path/-ep:	path where to export the binary
	--extra-flags/-ef:	extra flags to add to the command
	--login/-l		run the exported item in a login shell
	--sudo/-S:		specify if the exported item should be run as sudo
	--help/-h:		show this message
	--verbose/-v:		show more verbosity
	--version/-V:		show version
EOF
}

# Parse arguments
while :; do
	case $1 in
		-h | --help)
			# Call a "show_help" function to display a synopsis, then exit.
			show_help
			exit 0
			;;
		-v | --verbose)
			shift
			verbose=1
			;;
		-V | --version)
			printf "distrobox: %s\n" "${version}"
			exit 0
			;;
		-a | --app)
			if [ -n "$2" ]; then
				export_action="app"
				exported_app="$2"
				shift
				shift
			fi
			;;
		-b | --bin)
			if [ -n "$2" ]; then
				export_action="bin"
				exported_bin="$2"
				shift
				shift
			fi
			;;
		-l | --login)
			is_login=1
			shift
			;;
		-S | --sudo)
			is_sudo=1
			shift
			;;
		-el | --export-label)
			if [ -n "$2" ]; then
				exported_app_label="$2"
				shift
				shift
			fi
			;;
		-ep | --export-path)
			if [ -n "$2" ]; then
				dest_path="$2"
				shift
				shift
			fi
			;;
		-ef | --extra-flags)
			if [ -n "$2" ]; then
				extra_flags="$2"
				shift
				shift
			fi
			;;
		-d | --delete)
			exported_delete=1
			shift
			;;
		-*) # Invalid options.
			printf >&2 "ERROR: Invalid flag '%s'\n\n" "$1"
			show_help
			exit 1
			;;
		*) # Default case: If no more options then break out of the loop.
			break ;;
	esac
done

set -o errexit
set -o nounset
# set verbosity
if [ "${verbose}" -ne 0 ]; then
	set -o xtrace
fi

# Check we're running inside a container and not on the host.
if [ ! -f /run/.containerenv ] && [ ! -f /.dockerenv ] && [ -z "${container}" ]; then
	printf >&2 "You must run %s inside a container!\n" " $(basename "$0")"
	exit 126
fi

# Check if we're in a rootful or rootless container.
if grep -q "rootless=0" /run/.containerenv 2> /dev/null; then
	rootful="--root"
fi

# We're working with HOME, so we must run as USER, not as root.
if [ "$(id -u)" -eq 0 ]; then
	printf >&2 "You must not run %s as root!\n" " $(basename "$0")"
	exit 1
fi

# Ensure the foundamental variables are set and not empty, we will not proceed
# if they are not all set.
if [ -z "${exported_app}" ] &&
	[ -z "${exported_bin}" ]; then
	printf >&2 "Error: Invalid arguments.\n"
	printf >&2 "Error: missing export target. Run\n"
	printf >&2 "\tdistrobox-export --help\n"
	printf >&2 "for more information.\n"
	exit 2
fi
# Ensure we're not receiving more than one action at time.
if [ -n "${exported_app}" ] && [ -n "${exported_bin}" ]; then
	printf >&2 "Error: Invalid arguments, choose only one action below.\n"
	printf >&2 "Error: You can only export one thing at time.\n"
	exit 2
fi
# Ensure we have the export-path set when exporting a binary.
if [ -n "${exported_bin}" ] && [ -z "${dest_path}" ]; then
	printf >&2 "Error: Missing argument export-path.\n"
	exit 2
fi

if [ -n "${CONTAINER_ID}" ]; then
	container_name="${CONTAINER_ID}"
# if the variable is not set, let's fall back to some tricks.
elif [ -e /.dockerenv ]; then
	# we're in docker, let's use this trick
	container_name=$(grep "memory:/" < /proc/self/cgroup | sed 's|.*/||')
elif [ -e /run/.containerenv ]; then
	# we're in podman, use this other trick
	container_name=$(grep "name=" /run/.containerenv | cut -d'=' -f2- | tr -d '"')
fi
# If one of the previous methods didn't work
# let's fallback to a more simple way but error prone
if [ -z "${container_name}" ]; then
	container_name=$(uname -n | cut -d'.' -f1)
fi

#
if [ "${is_login}" -ne 0 ]; then
	if [ "${is_sudo}" -ne 0 ]; then
		start_shell="$(command -v sudo) -i"
	else
		start_shell="$(command -v sudo) -u ${USER} -i"
	fi
elif [ "${is_sudo}" -ne 0 ]; then
	start_shell="$(command -v sudo)"
else
	start_shell=""
fi

# Prefix to add to an existing command to work through the container
container_command_prefix="${DISTROBOX_ENTER_PATH:-"distrobox-enter"} ${rootful} -n ${container_name} -- ${start_shell} "
if [ -z "${exported_app_label}" ]; then
	exported_app_label=" (on ${container_name})"
fi

# Print generated script from template
# Arguments:
#	none it will use the ones set up globally
# Outputs:
#	print generated script.
generate_script() {
	cat << EOF
#!/bin/sh
# distrobox_binary
# name: ${container_name}
if [ -z "\${CONTAINER_ID}" ]; then
	exec "${DISTROBOX_ENTER_PATH:-"distrobox-enter"}" ${rootful} -n ${container_name} -- \
		${start_shell} ${exported_bin} ${extra_flags} "\$@"
elif [ -n "\${CONTAINER_ID}" ] && [ "\${CONTAINER_ID}" != "${container_name}" ]; then
	exec distrobox-host-exec ${dest_path}/$(basename "${exported_bin}") ${extra_flags} "\$@"
else
	exec ${exported_bin} "\$@"
fi
EOF
	return $?
}

# Export binary to destination directory.
# the following function will use generate_script to create a shell script in
# dest_path that will execute the exported binary in the selected distrobox.
#
# Arguments:
#	none it will use the ones set up globally
# Outputs:
#	a generated_script in dest_path
#	or error code.
export_binary() {
	# Ensure the binary we're exporting is installed
	if [ ! -f "${exported_bin}" ]; then
		printf >&2 "Error: cannot find %s.\n" "${exported_bin}"
		return 127
	fi
	# generate dest_file path
	dest_file="${dest_path}/$(basename "${exported_bin}")"

	# If we're deleting it, just do it and exit
	if [ "${exported_delete}" -ne 0 ] &&
		# ensure it's a distrobox exported binary
		grep -q "distrobox_binary" "${dest_file}"; then

		if rm -f "${dest_file}"; then
			printf "%s from %s removed successfully from %s.\nOK!\n" \
				"${exported_bin}" "${container_name}" "${dest_path}"
			return 0
		fi
	fi

	# test if we have writing rights on the file
	if ! touch "${dest_file}"; then
		printf >&2 "Error: cannot create destination file %s.\n" "${dest_file}"
		return 1
	fi

	# create the script from template and write to file
	if generate_script > "${dest_file}"; then
		chmod +x "${dest_file}"
		printf "%s from %s exported successfully in %s.\nOK!\n" \
			"${exported_bin}" "${container_name}" "${dest_path}"
		return 0
	fi
	# Unknown error.
	return 3
}

# Export graphical application to the host.
# the following function will scan the distrobox for desktop and icon files for
# the selected application. It will then put the needed icons in the host's icons
# directory and create a new .desktop file that will execute the selected application
# in the distrobox.
#
# Arguments:
#	none it will use the ones set up globally
# Outputs:
#	needed icons in /run/host/$host_home/.local/share/icons
#	needed desktop files in /run/host/$host_home/.local/share/applications
#	or error code.
export_application() {
	canon_dirs=""
	[ -d /usr/share/applications ] && canon_dirs="/usr/share/applications"
	[ -d /usr/local/share/applications ] && canon_dirs="${canon_dirs} /usr/local/share/applications"
	[ -d /var/lib/flatpak/exports/share/applications ] &&
		canon_dirs="${canon_dirs} /var/lib/flatpak/exports/share/applications"
	[ -d "${HOME}/.local/share/applications" ] && canon_dirs="${canon_dirs} ${HOME}/.local/share/applications"

	# In this phase we search for applications to export.
	# First find command will grep through all files in the canonical directories
	# and only list files that contain the $exported_app, excluding those that
	# already contains a distrobox-enter command. So skipping already exported apps.
	# Second find will list all files that contain the name specified, so that
	# it is possible to export an app not only by its executable name but also
	# by its launcher name.
	desktop_files=$(
		# shellcheck disable=SC2086,SC2038
		find ${canon_dirs} -type f -o -type l |
			xargs -I{} grep -le "Exec=.*${exported_app}.*" -le "Name=.*${exported_app}.*" "{}" |
			xargs -I{} grep -Le "Exec=.*${DISTROBOX_ENTER_PATH:-"distrobox-enter"}.*" "{}" |
			xargs -I{} printf "%s@" {}
	)

	# Ensure the app we're exporting is installed
	# Check that we found some desktop files first.
	if [ -z "${desktop_files}" ]; then
		printf >&2 "Error: cannot find any desktop files.\n"
		printf >&2 "Error: trying to export a non-installed application.\n"
		return 127
	fi

	# Find icons by usinc the Icon= specification. If it's only a name, we'll
	# search for the file, if it's already a path, just grab it.
	icon_files=""
	IFS="@"
	for desktop_file in ${desktop_files}; do
		if [ -z "${desktop_file}" ]; then
			continue
		fi

		icon_name="$(grep Icon= "${desktop_file}" | cut -d'=' -f2- | tr '\n' '@')"

		# In case it's an hard path, conserve it and continue
		if [ -e "${icon_name}" ]; then
			icon_files="${icon_files}@${icon_name}"
			continue
		fi
		for icon in ${icon_name}; do
			# If it's not an hard path, find all files in the canonical paths.
			icon_files="${icon_files}@$(find \
				/usr/share/icons \
				/usr/share/pixmaps \
				/var/lib/flatpak/exports/share/icons -iname "*${icon}*" \
				-printf "%p@" 2> /dev/null || :)"
		done
	done

	# create applications dir if not existing
	mkdir -p "/run/host${host_home}/.local/share/applications"

	# copy icons in home directory
	icon_file_absolute_path=""
	IFS="@"
	for icon_file in ${icon_files}; do
		if [ -z "${icon_file}" ]; then
			continue
		fi

		# replace canonical paths with equivalent paths in HOME
		icon_home_directory="$(dirname "${icon_file}" |
			sed "s|/usr/share/|\/run\/host\/${host_home}/.local/share/|g" |
			sed "s|/var/lib/flatpak/exports/share|\/run\/host\/${host_home}/.local/share/|g" |
			sed "s|pixmaps|icons|g")"

		# check if we're exporting an icon which is not in a canonical path
		if [ "${icon_home_directory}" = "$(dirname "${icon_file}")" ]; then
			icon_home_directory="/run/host${host_home}/.local/share/icons/"
			icon_file_absolute_path="${icon_home_directory}$(basename "${icon_file}")"
		fi

		# check if we're exporting or deleting
		if [ "${exported_delete}" -ne 0 ]; then
			# we need to remove, not export
			rm -rf "${icon_home_directory:?}"/"$(basename "${icon_file:?}")"
			continue
		fi

		# we wanto to export the application's icons
		mkdir -p "${icon_home_directory}"
		if [ ! -e "${icon_home_directory}/$(basename "${icon_file}")" ] && [ -e "$(realpath "${icon_file}")" ]; then
			cp -rf "$(realpath "${icon_file}")" "${icon_home_directory}"
		fi
	done

	# create desktop files for the distrobox
	IFS="@"
	for desktop_file in ${desktop_files}; do
		if [ -z "${desktop_file}" ]; then
			continue
		fi

		desktop_original_file="$(basename "${desktop_file}")"
		desktop_home_file="${container_name}-$(basename "${desktop_file}")"

		# check if we're exporting or deleting
		if [ "${exported_delete}" -ne 0 ]; then
			rm -f "/run/host${host_home}/.local/share/applications/${desktop_original_file}"
			rm -f "/run/host${host_home}/.local/share/applications/${desktop_home_file}"
			# we're done, go to next
			continue
		fi

		# Add command_prefix
		# Add extra flags
		# Add closing quote
		# If a TryExec is present, we have to fake it as it will not work
		# through the container separation
		sed "s|^Exec=|Exec=${container_command_prefix} |g" "${desktop_file}" |
			sed "s|\(%.*\)|${extra_flags} \1|g" |
			sed "/^TryExec=.*/d" |
			sed "/^DBusActivatable=true/d" |
			sed "s|Name.*|& ${exported_app_label}|g" \
				> "/run/host${host_home}/.local/share/applications/${desktop_home_file}"
		# in the end we add the final quote we've opened in the "container_command_prefix"

		if ! grep -q "StartupWMClass" "/run/host${host_home}/.local/share/applications/${desktop_home_file}"; then
			printf "StartupWMClass=%s\n" "${exported_app}" >> "\
/run/host${host_home}/.local/share/applications/${desktop_home_file}"
		fi
		# In case of an icon in a non canonical path, we need to replace the path
		# in the desktop file.
		if [ -n "${icon_file_absolute_path}" ]; then
			sed -i "s|Icon=.*|Icon=${icon_file_absolute_path}|g" \
				"/run/host${host_home}/.local/share/applications/${desktop_home_file}"
			# we're done, go to next
			continue
		fi

		# In case of an icon in a canonical path, but specified as an absolute
		# we need to replace the path in the desktop file.
		sed -i "s|Icon=/usr/share/|Icon=/run/host${host_home}/.local/share/|g" \
			"/run/host${host_home}/.local/share/applications/${desktop_home_file}"
		sed -i "s|pixmaps|icons|g" \
			"/run/host${host_home}/.local/share/applications/${desktop_home_file}"
	done

	# Update the desktop files database to ensure exported applications will
	# show up in the taskbar/desktop menu/whatnot right after running this
	# script.
	/usr/bin/distrobox-host-exec --yes update-desktop-database "${host_home}/.local/share/applications" 2> /dev/null || :

	if [ "${exported_delete}" -ne 0 ]; then
		printf "Application %s successfully un-exported.\nOK!\n" "${exported_app}"
		printf "%s will disappear from your applications list in a few seconds.\n" "${exported_app}"
	else
		printf "Application %s successfully exported.\nOK!\n" "${exported_app}"
		printf "%s will appear in your applications list in a few seconds.\n" "${exported_app}"
	fi

}

# Main routine
case "${export_action}" in
	app)
		export_application
		;;
	bin)
		export_binary
		;;
	*)
		printf >&2 "Invalid arguments, choose an action below.\n"
		show_help
		exit 2
		;;
esac