initial file capabilities support

1 files changed, 162 insertions, 0 deletions

diff --git a/eclass/fcaps.eclass b/eclass/fcaps.eclass
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+++ b/eclass/fcaps.eclass
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+# Copyright 1999-2013 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+# $Header: /var/cvsroot/gentoo-x86/eclass/fcaps.eclass,v 1.1 2013/01/27 17:27:10 vapier Exp $
+
+# @ECLASS: fcaps.eclass
+# @MAINTAINER:
+# Constanze Hausner <constanze@gentoo.org>
+# base-system@gentoo.org
+# @BLURB: function to set POSIX file-based capabilities
+# @DESCRIPTION:
+# This eclass provides a function to set file-based capabilities on binaries.
+#
+# Due to probable capability-loss on moving or copying, this happens in
+# pkg_postinst-phase (at least for now).
+#
+# @EXAMPLE:
+# You can manually set the caps on ping and ping6 by doing:
+# @CODE
+# pkg_postinst() {
+# 	fcaps cap_net_raw bin/ping bin/ping6
+# }
+# @CODE
+#
+# Or set it via the global ebuild var FILECAPS:
+# @CODE
+# FILECAPS=(
+# 	cap_net_raw bin/ping bin/ping6
+# )
+# @CODE
+
+if [[ ${___ECLASS_ONCE_FCAPS} != "recur -_+^+_- spank" ]] ; then
+___ECLASS_ONCE_FCAPS="recur -_+^+_- spank"
+
+IUSE="+filecaps"
+
+DEPEND="filecaps? ( sys-libs/libcap )"
+
+# @ECLASS-VARIABLE: FILECAPS
+# @DEFAULT_UNSET
+# @DESCRIPTION:
+# An array of fcap arguments to use to automatically execute fcaps.  See that
+# function for more details.
+#
+# All args are consumed until the '--' marker is found.  So if you have:
+# @CODE
+# 	FILECAPS=( moo cow -- fat cat -- chubby penguin )
+# @CODE
+#
+# This will end up executing:
+# @CODE
+# 	fcaps moo cow
+# 	fcaps fat cat
+# 	fcaps chubby penguin
+# @CODE
+#
+# Note: If you override pkg_postinst, you must call fcaps_pkg_postinst yourself.
+
+# @FUNCTION: fcaps
+# @USAGE: [-o <owner>] [-g <group>] [-m <mode>] <capabilities> <file[s]>
+# @DESCRIPTION:
+# Sets the specified capabilities on the specified files.
+#
+# The caps option takes the form as expected by the cap_from_text(3) man page.
+# If no action is specified, then "=ep" will be used as a default.
+#
+# If the file is a relative path (e.g. bin/foo rather than /bin/foo), then the
+# appropriate path var ($D/$ROOT/etc...) will be prefixed based on the current
+# ebuild phase.
+#
+# If the system is unable to set capabilities, it will use the specified user,
+# group, and mode (presumably to make the binary set*id).  The defaults there
+# are root:root and 4711.  Otherwise, the ownership and permissions will be
+# unchanged.
+fcaps() {
+	debug-print-function ${FUNCNAME} "$@"
+
+	# Process the user options first.
+	local owner='root'
+	local group='root'
+	local mode='4711'
+
+	while [[ $# -gt 0 ]] ; do
+		case $1 in
+		-o) owner=$2; shift;;
+		-g) group=$2; shift;;
+		-m) mode=$2; shift;;
+		*) break;;
+		esac
+		shift
+	done
+
+	[[ $# -lt 2 ]] && die "${FUNCNAME}: wrong arg count"
+
+	local caps=$1
+	[[ ${caps} == *[-=+]* ]] || caps+="=ep"
+	shift
+
+	local root
+	case ${EBUILD_PHASE} in
+	compile|install|preinst)
+		root=${ED:-${D}}
+		;;
+	postinst)
+		root=${EROOT:-${ROOT}}
+		;;
+	esac
+
+	# Process every file!
+	local file out
+	for file ; do
+		[[ ${file} != /* ]] && file="${root}${file}"
+
+		if use filecaps ; then
+			# Try to set capabilities.  Ignore errors when the
+			# fs doesn't support it, but abort on all others.
+			debug-print "${FUNCNAME}: setting caps '${caps}' on '${file}'"
+
+			if ! out=$(LC_ALL=C setcap "${caps}" "${file}" 2>&1) ; then
+				if [[ ${out} != *"Operation not supported"* ]] ; then
+					eerror "Setting caps '${caps}' on file '${file}' failed:"
+					eerror "${out}"
+					die "could not set caps"
+				else
+					local fstype=$(stat -f -c %T "${file}")
+					ewarn "Could not set caps on '${file}' due to missing filesystem support."
+					ewarn "Make sure you enable XATTR support for '${fstype}' in your kernel."
+				fi
+			else
+				# Sanity check that everything took.
+				setcap -v "${caps}" "${file}" >/dev/null \
+					|| die "Checking caps '${caps}' on '${file}' failed"
+
+				# Everything worked.  Move on to the next file.
+				continue
+			fi
+		fi
+
+		# If we're still here, setcaps failed.
+		debug-print "${FUNCNAME}: setting owner/mode on '${file}'"
+		chown "${owner}:${group}" "${file}" || die
+		chmod ${mode} "${file}" || die
+	done
+}
+
+# @FUNCTION: fcaps_pkg_postinst
+# @DESCRIPTION:
+# Process the FILECAPS array.
+fcaps_pkg_postinst() {
+	local arg args=()
+	for arg in "${FILECAPS[@]}" "--" ; do
+		if [[ ${arg} == "--" ]] ; then
+			fcaps "${args[@]}"
+			args=()
+		else
+			args+=( "${arg}" )
+		fi
+	done
+}
+
+EXPORT_FUNCTIONS pkg_postinst
+
+fi