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

# Ensure we have our env variables correctly set
[ -z "${USER}" ] && USER="$(id -run)"
[ -z "${HOME}" ] && HOME="$(getent passwd "${USER}" | cut -d':' -f6)"
[ -z "${SHELL}" ] && SHELL="$(getent passwd "${USER}" | cut -d':' -f7)"

# Defaults
export_action=""
exported_app=""
exported_app_label=""
exported_bin=""
exported_delete=0
extra_flags=""
enter_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="${DISTROBOX_EXPORT_PATH:-${host_home}/.local/bin}"
is_sudo=0
rootful=""
sudo_prefix=""
verbose=0
version="1.7.2.1"

sudo_askpass_path="${dest_path}/distrobox_sudo_askpass"
sudo_askpass_script="#!/bin/sh
if command -v zenity 2>&1 > /dev/null; then
	zenity --password
elif command -v kdialog 2>&1 > /dev/null; then
	kdialog --password
else
	exit 127
fi"

# 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

# show_help will print usage to stdout.
# Arguments:
#   None
# Expected global variables:
#   version: distrobox version
# Expected env variables:
#   None
# Outputs:
#   print usage with examples.
show_help()
{
	cat << EOF
distrobox version: ${version}

Usage:

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

Options:

	--app/-a:		name of the application to export
	--bin/-b:		absolute path of the binary to export
	--list-apps:		list applications exported from this container
	--list-binaries:	list binaries exported from this container, use -ep to specify custom paths to search
	--delete/-d:		delete exported application or binary
	--export-label/-el:	label to add to exported application name.
				Use "none" to disable.
				Defaults to (on \$container_name)
	--export-path/-ep:	path where to export the binary
	--extra-flags/-ef:	extra flags to add to the command
	--enter-flags/-nf:	flags to add to distrobox-enter
	--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
			;;
		--list-apps)
			export_action="list-apps"
			exported_bin="null"
			shift
			;;
		--list-binaries)
			export_action="list-binaries"
			exported_bin="null"
			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
			;;
		-nf | --enter-flags)
			if [ -n "$2" ]; then
				enter_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"

	# We need an askpass script for SUDO_ASKPASS, to launch graphical apps
	# from the drawer
	if [ ! -e "${sudo_askpass_path}" ]; then
		echo "${sudo_askpass_script}" > "${sudo_askpass_path}"
		chmod +x "${sudo_askpass_path}"
	fi
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=$(grep "memory:/" < /proc/self/cgroup | sed 's|.*/||')
elif [ -e /run/.containerenv ]; then
	# we're in podman or lilipod, use this other trick
	container_name=$(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

# Filter enter_flags and remove redundant options
if [ -n "${enter_flags}" ]; then
	# shellcheck disable=SC2086
	set -- ${enter_flags}
	filtered_flags=""
	# Inform user that certain flags are redundant
	while [ $# -gt 0 ]; do
		case "$1" in
			--root | -r)
				printf >&2 "Warning: %s argument will be set automatically and should be removed.\n" "${1}"
				;;
			--name | -n)
				printf >&2 "Warning: %s argument will be set automatically and should be removed.\n" "${1}"
				shift
				;;
			*)
				filtered_flags="${filtered_flags} $1"
				;;
		esac
		shift
	done
	enter_flags="${filtered_flags}"
fi

# Command to execute
container_command_suffix="'${exported_bin}' ${extra_flags} \"\$@\""

# Check if exported application/binary should be run with sudo privileges
if [ "${is_sudo}" -ne 0 ]; then
	sudo_prefix="sudo -S"

	# Edge case for systems without sudo
	if command -v su-exec > /dev/null >&1; then
		sudo_prefix="su-exec root"
		container_command_suffix="sh -l -c \"'${exported_bin}' ${extra_flags} \$*\""
	fi
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} ${enter_flags} -- ${sudo_prefix} "

if [ -n "${rootful}" ]; then
	container_command_prefix="env SUDO_ASKPASS=\"${sudo_askpass_path}\" DBX_SUDO_PROGRAM=\"sudo --askpass\" ${container_command_prefix}"
fi

if [ -z "${exported_app_label}" ]; then
	exported_app_label=" (on ${container_name})"
elif [ "${exported_app_label}" = "none" ]; then
	exported_app_label=""
else
	# Add a leading space so that we can have "NAME LABEL" in the entry
	exported_app_label=" ${exported_app_label}"
fi

# generate_script will generate a script from template. This script will wrap the
# exported binary in order to ensure it will be executed in the right container.
# Arguments:
#	None
# Expected global variables:
#   CONTAINER_ID: id of the current container
#   container_command_suffix: string to postpone to the command to launch
#   container_name:  string name of this container
#   dest_path: string path where to export the binary
#   enter_flags:  string extra flags to append to the distrobox enter command
#   exported_bin: string path to the binary to export
#   exported_delete: bool delete the binary exported
#   extra_flags:  string extra flags to append to the exported app command
#   rootful: bool if this is a rootful container
#   sudo_prefix: string sudo command to prepend to the exported command
# Expected env variables:
#   None
# 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} ${enter_flags} -- ${sudo_prefix} ${container_command_suffix}
elif [ -n "\${CONTAINER_ID}" ] && [ "\${CONTAINER_ID}" != "${container_name}" ]; then
	exec distrobox-host-exec '${dest_path}/$(basename "${exported_bin}")' "\$@"
else
	exec '${exported_bin}' "\$@"
fi
EOF
	return $?
}

# export_binary will export selected 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
# Expected global variables:
#   CONTAINER_ID: id of the current container
#   container_name: string name of this container
#   dest_path: string path where to export the binary
#   exported_bin: string path to the binary to export
#   exported_delete: bool delete the binary exported
# Expected env variables:
#   None
# 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}")"

	# create the binary destination path if it doesn't exist
	mkdir -p "${dest_path}"

	# If we're deleting it, just do it and exit
	if [ "${exported_delete}" -ne 0 ]; then
		# ensure it's a distrobox exported binary
		if ! grep -q "distrobox_binary" "${dest_file}"; then
			printf >&2 "Error: %s is not exported.\n" "${exported_bin}"
			return 1
		fi

		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
		return 1
	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_application will export input 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
# Expected global variables:
#   CONTAINER_ID: id of the current container
#   container_command_prefix: string to prepend to the command to launch
#   container_name:  string name of this container
#   exported_app:   string name of the app to export
#   exported_app_label: string label to use to mark the exported app
#   exported_delete:  bool if we want to delete or not
#   extra_flags:  string extra flags to append to the exported app command
#   host_home: home path ofr the host, where to search desktop files
# Expected env variables:
#   None
# 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=""

	IFS=":"
	if [ -n "${XDG_DATA_DIRS}" ]; then
		for xdg_data_home in ${XDG_DATA_HOME}; do
			[ -d "${xdg_data_home}/applications" ] && canon_dirs="${canon_dirs} ${xdg_data_home}/applications"
		done
	else
		[ -d /usr/share/applications ] && canon_dirs="/usr/share/applications"
		[ -d /usr/local/share/applications ] && canon_dirs="${canon_dirs} /usr/local/share/applications"
		[ -d /var/lib/flatpak/exports/share/applications ] && canon_dirs="${canon_dirs} /var/lib/flatpak/exports/share/applications"
	fi
	if [ -n "${XDG_DATA_HOME}" ]; then
		for xdg_data_dir in ${XDG_DATA_DIRS}; do
			[ -d "${xdg_data_dir}/applications" ] && canon_dirs="${canon_dirs} ${xdg_data_dir}/applications"
		done
	else
		[ -d "${HOME}/.local/share/applications" ] && canon_dirs="${canon_dirs} ${HOME}/.local/share/applications"
	fi
	unset IFS

	# 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
		find ${canon_dirs} -type f -print -o -type l -print | sed 's/./\\&/g' |
			xargs -I{} grep -l -e "Exec=.*${exported_app}.*" -e "Name=.*${exported_app}.*" "{}" | sed 's/./\\&/g' |
			xargs -I{} grep -L -e "Exec=.*${DISTROBOX_ENTER_PATH:-"distrobox.*enter"}.*" "{}" | sed 's/./\\&/g' |
			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 using 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- | paste -sd "¤" -)"

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

		# remove leading delimiter
		icon_files=${icon_files#¤}
	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 "${icon_file}")" ]; then
			icon_home_directory="${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=${container_command_prefix} \1 |g" "${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" > /dev/null 2>&1 || :

	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
}

# list_exported_applications will print all exported applications in canonical directories.
# the following function will list exported desktop files from this container.
#
# Arguments:
#	None
# Expected global variables:
#   host_home: home path ofr the host, where to search desktop files
#   CONTAINER_ID: id of the current container
# Expected env variables:
#   None
# Outputs:
#	a list of exported apps
#	or error code.
list_exported_applications()
{
	# In this phase we search for applications exported.
	# First find command will grep through all files in the canonical directories
	# and only list files that contain the $DISTROBOX_ENTER_PATH.
	desktop_files=$(
		# shellcheck disable=SC2086
		find "/run/host${host_home}/.local/share/applications" -type f -print -o -type l -print 2> /dev/null | sed 's/./\\&/g' |
			xargs -I{} grep -l -e "Exec=.*${DISTROBOX_ENTER_PATH:-"distrobox.*enter"}.*" "{}" | sed 's/./\\&/g' |
			xargs -I{} printf "%s¤" "{}"
	)

	# Then we try to pretty print them.
	IFS="¤"
	for i in ${desktop_files}; do
		# Get app name, and remove label
		name="$(grep -Eo 'Name=.*' "${i}" | head -n 1 | cut -d'=' -f2- | sed 's|(.*)||g')"
		# Print only stuff we exported from this box!
		if echo "${i}" | grep -q "${CONTAINER_ID}"; then
			printf "%-20s | %-30s\n" "${name}" "${i}"
		fi
	done
}

# list_exported_binaries will print all exported binaries.
# the following function will list exported desktop files from this container.
# If no export-path is specified, it searches in the default path.
#
# Arguments:
#	None
# Expected global variables:
#   dest_path: destination path where to search binaries
#   CONTAINER_ID: id of the current container
# Expected env variables:
#	None
# Outputs:
#	a list of exported apps
#	or error code.
list_exported_binaries()
{
	# In this phase we search for binaries exported.
	# First find command will grep through all files in the canonical directories
	# and only list files that contain the comment "# distrobox_binary".
	binary_files=$(
		find "${dest_path}" -type f -print 2> /dev/null | sed 's/./\\&/g' |
			xargs -I{} grep -l -e "^# distrobox_binary" "{}" | sed 's/./\\&/g' |
			xargs -I{} printf "%s¤" "{}"
	)

	# Then we try to pretty print them.
	IFS="¤"
	for i in ${binary_files}; do
		if [ -z "${i}" ]; then
			continue
		fi
		# Get original binary name
		name="$(grep -B1 "fi" "${i}" | grep exec | cut -d' ' -f2)"
		# Print only stuff we exported from this box!
		if grep "^# name:.*" "${i}" | grep -q "${CONTAINER_ID}"; then
			printf "%-20s | %-30s\n" "${name}" "${i}"
		fi
	done
}

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