# Copyright (c) 2017 The NetBSD Foundation, Inc.
# All rights reserved.
#
# This code is derived from software contributed to The NetBSD Foundation
# by Johnny C. Lam.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
# ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
# TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
#
# NAME
#	shells.subr -- shell database management for packages
#
# SYNOPSIS
#	task_shells [-s] add | remove
#	task_shells check-add | check-remove
#
# DESCRIPTION
#	The task_shells function supports four actions: "add", "remove",
#	"check-add", and "check-remove".
#
#	The available options are as follows:
#
#	-s	Silent; don't write to standard output.
#
#	The task_shells function reads standard input line by line and
#	looks for lines of the form:
#
#	    # SHELL: <shell_path> [<shelldb_path>]
#
#	If any of the paths are relative, then they are assumed to be
#	relative to ${PKG_PREFIX}.
#
#	The "add" action adds shell paths to the shell database.
#
#	The "remove" action removes shell paths from the shell database.
#
#	The "check-add" action will check whether shell paths are missing
#	from the shell database and writes an informative message noting
#	the missing shell paths.
#
#	The "check-remove" action will check whether shell paths are
#	still present in the shell database and writes an informative
#	message noting the existing paths.
#
# RETURN VALUES
#	The "add" and "remove" actions return 0 if they are successful
#	for all shell paths, and >0 if an error occurs.
#
#	The "check-add" and "check-remove" actions return >0 if they
#	write informative messages, and return 0 otherwise.
#
# ENVIRONMENT
#	The following variables are used if they are set:
#
#	MV	The name or path to the mv(1) utility.
#
#	PKGNAME
#		The name of the package.
#
#	PKG_DESTDIR
#		A "destdir" prefix that is prepended to all filesystem
#		paths.  The default value is the empty string.
#
#	PKG_REGISTER_SHELLS
#		If ${PKG_REGISTER_SHELLS} is a "truthy" value, then the
#		"add" and "remove" actions are allowed to modify the shell
#		databases as needed.
#
#	PKG_PREFIX
#		The installation prefix of the package.  The default is
#		"/usr/pkg".
#
#	RM	The name or path to the rm(1) utility.
#
#	TASK_MSG
#		String prepended to all normal message written to
#		standard output.
#

__task_shells__="yes"
__task_shells_init__="_task_shells_init"

task_load cleanup
task_load echo
task_load lock
task_load makedir
task_load maketemp
task_load match
task_load quote
task_load truthy

task_shells()
{
	: ${CP:=cp}
	: ${MV:=mv}

	: ${PKG_PREFIX:=/usr/pkg}
	: ${PKGNAME:=${0##*/}}

	: ${PKG_REGISTER_SHELLS:=yes}
	: ${TASK_MSG:=""}

	local arg
	local echo="task_echo"
	local OPTIND=1
	while getopts ":s" arg "$@"; do
		case $arg in
		s)	echo=":" ;;
		*)	return 127 ;;
		esac
	done
	shift $(( ${OPTIND} - 1 ))
	[ $# -gt 0 ] || return 127

	local action="$1"; shift
	case $action in
	add|remove|check-add|check-remove)
		: "valid actions" ;;
	*)	return 0 ;;
	esac

	# Guard against ${PKG_PREFIX} == "/".
	local prefix
	case ${PKG_PREFIX}/ in
	//)	prefix= ;;
	*)	prefix=${PKG_PREFIX} ;;
	esac

	local register_shells="yes"
	task_is_truthy "${PKG_REGISTER_SHELLS}" || register_shells=

	local result line_result
	local quoted
	local lock lock_quoted
	local temp temp_quoted

	result=0
	local hash tag shell shelldb
	while read hash tag shell shelldb; do
		# Filter for "# SHELL:".
		case $hash/$tag in
		"#/SHELL:")
			: "use this line" ;;
		*)	continue ;;
		esac

		# Canonicalize paths.
		case $shell in
		"")	# skip lines without any required args
			continue ;;
		[!/]*)	shell="$prefix/$shell" ;;
		esac
		case $shelldb in
		"")	shelldb="/etc/shells" ;;
		[!/]*)	shelldb="$prefix/$shelldb" ;;
		esac
		shelldb="${PKG_DESTDIR}$shelldb"
		local shelldbdir=${shelldb%/*}

		line_result=0
		case $action in
		add|remove)
			# Ensure that the shelldb directory exists.
			[ -d "$shelldbdir" ] || task_makedir "$shelldbdir" 2>/dev/null
			[ -d "$shelldbdir" ] || line_result=1
			if [ $line_result -eq 0 ]; then
				lock="$shelldb.lock"
				task_quote "$lock"
				lock_quoted=$quoted
				__task_shells_locks__="$lock_quoted $__task_shells_locks__"
				task_lock "$lock" || line_result=1
			fi ;;
		esac
		if [ $line_result -eq 0 ]; then
			case $action in
			add)	if [ -n "$register_shells" ]; then
					if [ -f "$shelldb" ] && task_match -qw "$shell" < $shelldb; then
						$echo "${TASK_MSG}! shell already added: $shell"
					else
						temp=$( task_maketemp "$shelldb.pkgtasks.XXXXXXXXXX" )
						if [ -n "$temp" ]; then
							task_quote "$temp"
							temp_quoted="$quoted"
							__task_shells_temps__="$__task_shells_temps__ $temp_quoted"
							if [ -f "$shelldb" ]; then
								# Preserve existing ownership and permissions onto tempfile.
								${CP} -fp "$shelldb" "$temp"
								# Overwrite contents of tempfile.
								{ task_match -vw "$shell" < $shelldb; echo "$shell"; } > $temp
							else
								echo "$shell" > $temp
							fi
							# rename(2) is atomic.
							if ${MV} -f "$temp" "$shelldb"; then
								$echo "${TASK_MSG}> shell added: $shell"
								__task_shells_temps__=${__task_shells_temps__% $temp_quoted}
							else
								$echo "${TASK_MSG}! shell not added: $shell"
								line_result=1
							fi
						else
							$echo "${TASK_MSG}! cannot create temporary file for $shelldb"
							line_result=1
						fi
					fi
				fi ;;
			remove)	if [ -n "$register_shells" ]; then
					if [ -f "$shelldb" ] && task_match -qw "$shell" < $shelldb; then
						temp=$( task_maketemp "$shelldb.pkgtasks.XXXXXXXXXX" )
						if [ -n "$temp" ]; then
							task_quote "$temp"
							temp_quoted="$quoted"
							__task_shells_temps__="$__task_shells_temps__ $temp_quoted"
							# Preserve existing ownership and permissions onto tempfile.
							${CP} -fp "$shelldb" "$temp"
							# Overwrite contents of tempfile.
							task_match -vw "$shell" < $shelldb > $temp
							# rename(2) is atomic.
							if ${MV} -f "$temp" "$shelldb"; then
								$echo "${TASK_MSG}> shell removed: $shell"
								__task_shells_temps__=${__task_shells_temps__% $temp_quoted}
							else
								$echo "${TASK_MSG}! shell not removed: $shell"
								line_result=1
							fi
						else
							$echo "${TASK_MSG}! cannot create temporary file for $shelldb"
							line_result=1
						fi
					else
						$echo "${TASK_MSG}! shell already removed: $shell"
					fi
				fi ;;
			check-add)
				if [ -f "$shelldb" ] && task_match -qw "$shell" < $shelldb; then
				   	: "shell already added"
				else
					task_echo "!!! INFO: ${PKGNAME}: Add shell \"$shell\" to $shelldb."
					line_result=1
				fi ;;
			check-remove)
				if [ -f "$shelldb" ] && task_match -qw "$shell" < $shelldb; then
					task_echo "!!! INFO: ${PKGNAME}: Remove shell \"$shell\" from $shelldb."
					line_result=1
				fi ;;
			esac
		fi
		case $action in
		add|remove)
			task_lock -r "$lock"
			__task_shells_locks__=${__task_shells_locks__#$lock_quoted } ;;
		esac
		[ $line_result -eq 0 ] || result=1
	done

	_task_shells_cleanup
	return $result
}

_task_shells_cleanup()
{
	: ${RM:=rm}

	eval set -- $__task_shells_temps__
	local file
	for file; do
		${RM} -f "$file"
	done
	__task_shells_temps__=

	eval set -- $__task_shells_locks__
	local lockfile
	for lockfile; do
		task_lock -r "$lockfile"
	done
	__task_shells_locks__=
}

_task_shells_init()
{
	task_cleanup_add_hook _task_shells_cleanup
}

# Static variable for temporary files that should be removed in an error occurs.
__task_shells_temps__=
# Static variable for locks that should be released if an error occurs.
__task_shells_locks__=