# Copyright 2011-2023 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2

# @ECLASS: systemd.eclass
# @MAINTAINER:
# systemd@gentoo.org
# @SUPPORTED_EAPIS: 5 6 7 8
# @BLURB: helper functions to install systemd units
# @DESCRIPTION:
# This eclass provides a set of functions to install unit files for
# sys-apps/systemd within ebuilds.
# @EXAMPLE:
#
# @CODE
# inherit systemd
#
# src_configure() {
#	local myconf=(
#		--enable-foo
#		--with-systemdsystemunitdir="$(systemd_get_systemunitdir)"
#	)
#
#	econf "${myconf[@]}"
# }
# @CODE

case ${EAPI} in
	5|6|7|8) ;;
	*) die "${ECLASS}: EAPI ${EAPI:-0} not supported" ;;
esac

inherit toolchain-funcs

if [[ ${EAPI} == [56] ]]; then
	DEPEND="virtual/pkgconfig"
else
	BDEPEND="virtual/pkgconfig"
fi

# @FUNCTION: _systemd_get_dir
# @USAGE: <variable-name> <fallback-directory>
# @INTERNAL
# @DESCRIPTION:
# Try to obtain the <variable-name> variable from systemd.pc.
# If pkg-config or systemd is not installed, return <fallback-directory>
# instead.
_systemd_get_dir() {
	[[ ${#} -eq 2 ]] || die "Usage: ${FUNCNAME} <variable-name> <fallback-directory>"
	local variable=${1} fallback=${2} d

	# https://github.com/pkgconf/pkgconf/issues/205
	local -x PKG_CONFIG_FDO_SYSROOT_RULES=1

	if $(tc-getPKG_CONFIG) --exists systemd; then
		d=$($(tc-getPKG_CONFIG) --variable="${variable}" systemd) || die
	else
		d="${EPREFIX}${fallback}"
	fi

	echo "${d}"
}

# @FUNCTION: _systemd_unprefix
# @USAGE: <function-name>
# @INTERNAL
# @DESCRIPTION:
# Calls the specified function and removes ${EPREFIX} from the result.
_systemd_unprefix() {
	local d=$("${@}")
	echo "${d#"${EPREFIX}"}"
}

# @FUNCTION: systemd_get_systemunitdir
# @DESCRIPTION:
# Output the path for the systemd system unit directory (not including
# ${D}).  This function always succeeds, even if systemd is not
# installed.
systemd_get_systemunitdir() {
	debug-print-function ${FUNCNAME} "${@}"

	_systemd_get_dir systemdsystemunitdir /lib/systemd/system
}

# @FUNCTION: systemd_get_unitdir
# @DESCRIPTION:
# Deprecated alias for systemd_get_systemunitdir.
systemd_get_unitdir() {
	[[ ${EAPI} == 5 ]] || die "${FUNCNAME} is banned in EAPI 6, use systemd_get_systemunitdir instead"

	systemd_get_systemunitdir
}

# @FUNCTION: systemd_get_userunitdir
# @DESCRIPTION:
# Output the path for the systemd user unit directory (not including
# ${D}). This function always succeeds, even if systemd is not
# installed.
systemd_get_userunitdir() {
	debug-print-function ${FUNCNAME} "${@}"

	_systemd_get_dir systemduserunitdir /usr/lib/systemd/user
}

# @FUNCTION: systemd_get_utildir
# @DESCRIPTION:
# Output the path for the systemd utility directory (not including
# ${D}). This function always succeeds, even if systemd is not
# installed.
systemd_get_utildir() {
	debug-print-function ${FUNCNAME} "${@}"

	_systemd_get_dir systemdutildir /lib/systemd
}

# @FUNCTION: systemd_get_systemgeneratordir
# @DESCRIPTION:
# Output the path for the systemd system generator directory (not including
# ${D}). This function always succeeds, even if systemd is not installed.
systemd_get_systemgeneratordir() {
	debug-print-function ${FUNCNAME} "${@}"

	_systemd_get_dir systemdsystemgeneratordir /lib/systemd/system-generators
}

# @FUNCTION: systemd_get_systempresetdir
# @DESCRIPTION:
# Output the path for the systemd system preset directory (not including
# ${D}). This function always succeeds, even if systemd is not installed.
systemd_get_systempresetdir() {
	debug-print-function ${FUNCNAME} "${@}"

	_systemd_get_dir systemdsystempresetdir /lib/systemd/system-preset
}

# @FUNCTION: systemd_get_sleepdir
# @DESCRIPTION:
# Output the path for the system sleep directory.
systemd_get_sleepdir() {
	debug-print-function ${FUNCNAME} "${@}"
	_systemd_get_dir systemdsleepdir /lib/systemd/system-sleep
}

# @FUNCTION: systemd_dounit
# @USAGE: <unit>...
# @DESCRIPTION:
# Install systemd unit(s). Uses doins, thus it is fatal.
systemd_dounit() {
	debug-print-function ${FUNCNAME} "${@}"

	(
		insopts -m 0644
		insinto "$(_systemd_unprefix systemd_get_systemunitdir)"
		doins "${@}"
	)
}

# @FUNCTION: systemd_newunit
# @USAGE: <old-name> <new-name>
# @DESCRIPTION:
# Install systemd unit with a new name. Uses newins, thus it is fatal.
systemd_newunit() {
	debug-print-function ${FUNCNAME} "${@}"

	(
		insopts -m 0644
		insinto "$(_systemd_unprefix systemd_get_systemunitdir)"
		newins "${@}"
	)
}

# @FUNCTION: systemd_douserunit
# @USAGE: <unit>...
# @DESCRIPTION:
# Install systemd user unit(s). Uses doins, thus it is fatal.
systemd_douserunit() {
	debug-print-function ${FUNCNAME} "${@}"

	(
		insopts -m 0644
		insinto "$(_systemd_unprefix systemd_get_userunitdir)"
		doins "${@}"
	)
}

# @FUNCTION: systemd_newuserunit
# @USAGE: <old-name> <new-name>
# @DESCRIPTION:
# Install systemd user unit with a new name. Uses newins, thus it
# is fatal.
systemd_newuserunit() {
	debug-print-function ${FUNCNAME} "${@}"

	(
		insopts -m 0644
		insinto "$(_systemd_unprefix systemd_get_userunitdir)"
		newins "${@}"
	)
}

# @FUNCTION: systemd_install_serviced
# @USAGE: <conf-file> [<service>]
# @DESCRIPTION:
# Install <conf-file> as the template <service>.d/00gentoo.conf.
# If <service> is not specified
# <conf-file> with the .conf suffix stripped is used
# (e.g. foo.service.conf -> foo.service.d/00gentoo.conf).
systemd_install_serviced() {
	debug-print-function ${FUNCNAME} "${@}"

	local src=${1}
	local service=${2}

	[[ ${src} ]] || die "No file specified"

	if [[ ! ${service} ]]; then
		[[ ${src} == *.conf ]] || die "Source file needs .conf suffix"
		service=${src##*/}
		service=${service%.conf}
	fi
	# avoid potentially common mistake
	[[ ${service} == *.d ]] && die "Service must not have .d suffix"

	(
		insopts -m 0644
		insinto /etc/systemd/system/"${service}".d
		newins "${src}" 00gentoo.conf
	)
}

# @FUNCTION: systemd_install_dropin
# @USAGE: [--user] <unit> <conf-file>
# @DESCRIPTION:
# Install <conf-file> as the dropin file <unit>.d/00gentoo.conf,
# overriding the settings of <unit>.
# Defaults to system unit dropins, unless --user is provided,
# which causes the dropin to be installed for user units.
# The required argument <conf-file> may be '-', in which case the
# file is read from stdin and <unit> must also be specified.
# @EXAMPLE:
# systemd_install_dropin foo.service "${FILESDIR}/foo.service.conf"
# systemd_install_dropin foo.service - <<-EOF
# 	[Service]
# 	RestartSec=120
# EOF
systemd_install_dropin() {
	debug-print-function ${FUNCNAME} "${@}"

	local basedir
	if [[ $# -ge 1 ]] && [[ $1 == "--user" ]]; then
		basedir=$(_systemd_unprefix systemd_get_userunitdir)
		shift 1
	else
		basedir=$(_systemd_unprefix systemd_get_systemunitdir)
	fi

	local unit=${1}
	local src=${2}

	[[ ${unit} ]] || die "No unit specified"
	[[ ${src} ]] || die "No conf file specified"

	# avoid potentially common mistake
	[[ ${unit} == *.d ]] && die "Unit ${unit} must not have .d suffix"

	(
		insopts -m 0644
		insinto "${basedir}/${unit}".d
		newins "${src}" 00gentoo.conf
	)
}

# @FUNCTION: systemd_enable_service
# @USAGE: <target> <service>
# @DESCRIPTION:
# Enable service in desired target, e.g. install a symlink for it.
# Uses dosym, thus it is fatal.
systemd_enable_service() {
	debug-print-function ${FUNCNAME} "${@}"

	[[ ${#} -eq 2 ]] || die "Synopsis: systemd_enable_service target service"

	local target=${1}
	local service=${2}
	local ud=$(_systemd_unprefix systemd_get_systemunitdir)
	local destname=${service##*/}

	dodir "${ud}"/"${target}".wants && \
	dosym ../"${service}" "${ud}"/"${target}".wants/"${destname}"
}

# @FUNCTION: systemd_enable_ntpunit
# @USAGE: <NN-name> <service>...
# @DESCRIPTION:
# Add an NTP service provider to the list of implementations
# in timedated. <NN-name> defines the newly-created ntp-units.d priority
# and name, while the remaining arguments list service units that will
# be added to that file.
#
# Uses doins, thus it is fatal.
#
# Doc: https://www.freedesktop.org/wiki/Software/systemd/timedated/
systemd_enable_ntpunit() {
	debug-print-function ${FUNCNAME} "${@}"
	if [[ ${#} -lt 2 ]]; then
		die "Usage: systemd_enable_ntpunit <NN-name> <service>..."
	fi

	local ntpunit_name=${1}
	local services=( "${@:2}" )

	if [[ ${ntpunit_name} != [0-9][0-9]-* ]]; then
		die "ntpunit.d file must be named NN-name where NN are digits."
	elif [[ ${ntpunit_name} == *.list ]]; then
		die "The .list suffix is appended implicitly to ntpunit.d name."
	fi

	local unitdir=$(systemd_get_systemunitdir)
	local s
	for s in "${services[@]}"; do
		if [[ ! -f "${D}${unitdir}/${s}" ]]; then
			die "ntp-units.d provider ${s} not installed (yet?) in \${D}."
		fi
		echo "${s}" >> "${T}"/${ntpunit_name}.list || die
	done

	(
		insopts -m 0644
		insinto "$(_systemd_unprefix systemd_get_utildir)"/ntp-units.d
		doins "${T}"/${ntpunit_name}.list
	)
	local ret=${?}

	rm "${T}"/${ntpunit_name}.list || die

	return ${ret}
}

# @FUNCTION: systemd_with_unitdir
# @USAGE: [<configure-option-name>]
# @DESCRIPTION:
# Note: deprecated and banned in EAPI 6. Please use full --with-...=
# parameter for improved ebuild readability.
#
# Output '--with-systemdsystemunitdir' as expected by systemd-aware configure
# scripts. This function always succeeds. Its output may be quoted in order
# to preserve whitespace in paths. systemd_to_myeconfargs() is preferred over
# this function.
#
# If upstream does use invalid configure option to handle installing systemd
# units (e.g. `--with-systemdunitdir'), you can pass the 'suffix' as an optional
# argument to this function (`$(systemd_with_unitdir systemdunitdir)'). Please
# remember to report a bug upstream as well.
systemd_with_unitdir() {
	[[ ${EAPI} == 5 ]] || die "${FUNCNAME} is banned in EAPI ${EAPI}, use --with-${1:-systemdsystemunitdir}=\"\$(systemd_get_systemunitdir)\" instead"

	debug-print-function ${FUNCNAME} "${@}"
	local optname=${1:-systemdsystemunitdir}

	echo --with-${optname}="$(systemd_get_systemunitdir)"
}

# @FUNCTION: systemd_with_utildir
# @DESCRIPTION:
# Note: deprecated and banned in EAPI 6. Please use full --with-...=
# parameter for improved ebuild readability.
#
# Output '--with-systemdsystemutildir' as used by some packages to install
# systemd helpers. This function always succeeds. Its output may be quoted
# in order to preserve whitespace in paths.
systemd_with_utildir() {
	[[ ${EAPI} == 5 ]] || die "${FUNCNAME} is banned in EAPI ${EAPI}, use --with-systemdutildir=\"\$(systemd_get_utildir)\" instead"

	debug-print-function ${FUNCNAME} "${@}"

	echo --with-systemdutildir="$(systemd_get_utildir)"
}

# @FUNCTION: systemd_update_catalog
# @DESCRIPTION:
# Update the journald catalog. This needs to be called after installing
# or removing catalog files. This must be called in pkg_post* phases.
#
# If systemd is not installed, no operation will be done. The catalog
# will be (re)built once systemd is installed.
#
# See: https://www.freedesktop.org/wiki/Software/systemd/catalog
systemd_update_catalog() {
	debug-print-function ${FUNCNAME} "${@}"

	[[ ${EBUILD_PHASE} == post* ]] \
		|| die "${FUNCNAME} disallowed during ${EBUILD_PHASE_FUNC:-${EBUILD_PHASE}}"

	# Make sure to work on the correct system.

	local journalctl=${EPREFIX}/usr/bin/journalctl
	if [[ -x ${journalctl} ]]; then
		ebegin "Updating systemd journal catalogs"
		journalctl --update-catalog
		eend $?
	else
		debug-print "${FUNCNAME}: journalctl not found."
	fi
}

# @FUNCTION: systemd_is_booted
# @DESCRIPTION:
# Check whether the system was booted using systemd.
#
# This should be used purely for informational purposes, e.g. warning
# user that he needs to use systemd. Installed files or application
# behavior *must not* rely on this. Please remember to check MERGE_TYPE
# to not trigger the check on binary package build hosts!
#
# Returns 0 if systemd is used to boot the system, 1 otherwise.
#
# See: man sd_booted
systemd_is_booted() {
	debug-print-function ${FUNCNAME} "${@}"

	[[ -d /run/systemd/system ]]
	local ret=${?}

	debug-print "${FUNCNAME}: [[ -d /run/systemd/system ]] -> ${ret}"
	return ${ret}
}

# @FUNCTION: systemd_reenable
# @USAGE: <unit> ...
# @DESCRIPTION:
# Re-enables units if they are currently enabled. This resets symlinks to the
# defaults specified in the [Install] section.
#
# This function is intended to fix broken symlinks that result from moving
# the systemd system unit directory. It should be called from pkg_postinst
# for system units that define the 'Alias' option in their [Install] section.
# It is not necessary to call this function to fix dependency symlinks
# generated by the 'WantedBy' and 'RequiredBy' options.
systemd_reenable() {
	type systemctl &>/dev/null || return 0
	local x
	for x; do
		if systemctl --quiet --root="${ROOT:-/}" is-enabled "${x}"; then
			systemctl --root="${ROOT:-/}" reenable "${x}"
		fi
	done
}