user.* xattr preserving wrapper for install

install (text/plain), 4.05 KB, created by Anthony Basile on 2013-06-19 22:11:38 UTC

#!/bin/bash
# Copyright 1999-2013 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2

source "${PORTAGE_BIN_PATH:-/usr/lib/portage/bin}"/isolated-functions.sh

__getxattrs()
{
	# Global variables.
	#
	# Note the mapping between file, namespace, xattr value is as follows.
	# Suppose our array of source files looks like:
	#
	#    ${__source_files[@]}=( 'aaa', 'bbb', 'ccc', 'ddd' )
	#
	# Since 'aaa' is at index 0, its xattr names and values look like
	#
	#    ${__xattr_names_0_['n1']}='v1'
	#    ${__xattr_names_0_['n2']}='v2'
	#    ...
	#
	# and similarly for bbb, ccc and ddd, with _0_ replaced by _1_, _2_ and _3_.
	#

	__source_files=()
	__target=""
	__target_is_directory="no"

	local arg args=()
	local ignored_flags=(
		"-b" "--backup"
		"-c"
		"-C" "--compare"
		"-D"
		"-o" "--owner"
		"-g" "--group"
		"-m" "--mode"
		"-p" "--preserve-timestamps"
		"-s" "--strip" "--strip-program"
		"-S" "--suffix"
		"-T" "--no-target-directory"
		"-Z" "--context" "--preserve-context"
		"-v" "--verbose"
		"--help"
		"--version"
	)

	local skip="no"

	for arg in "$@"; do

		# Nothing to do if the -d/--directory flag is given
		# Zero what we've already gotten and return
		if [[ "$arg" == -d || "$arg" == --directory ]]; then
			__source_files=()
			__target=""
			__target_is_directory="no"
			return 0
		fi

		# We may be asked to skip this argument because we know it is
		# the target directory --- see where we set skip="yes" below
		if [[ "$skip" == "yes" ]]; then
			skip="no"
			__target="$arg"
		fi

		# Skip flags that we don't need to parse out source/destination
		local ignore="no"
		for flag in "${ignored_flags[@]}"; do
			if [[ "$arg" == "$flag"* ]]; then
				ignore="yes"
				break
			fi
		done
		[[ "$ignore" == "yes" ]] && continue

		# If the --target-directory= flag is given then the target is a diretory
		# Note: there can be no space before or after the =
		if [[ "$arg" == --target-directory=* ]] ; then
			__target_is_directory="yes"
			$__target="${arg/--target-directory=/}"
		fi

		# If the -t flag is given then the target is a diretory
		if [[ "$arg" == -t* ]]; then
			__target_is_directory="yes"

			# There may be zero or more spaces between -t and the target directory.  If
			# there is one or more, then we'll get the target directory on the next iteration.
			if [[ -z "${arg/-t/}" ]]; then
				skip="yes"
				continue
			else
				__target="${arg#-t}"
			fi
		fi

		__source_files+=( "$arg" )
	done

	# If we haven't found a target yet, then the last in the remaining list is the target
	if [[ -z "$__target" ]]; then
		local last="${#__source_files[@]}"
		(( last -= 1 ))
		__target="${__source_files[$last]}"
		unset __source_files[$last]

		# Is the target a directory?
		[[ -d $__target ]] && __target_is_directory="yes"
	fi

	local file
	local index=0
	for file in "${__source_files[@]}"; do
		local narray="__xattr_names_${index}_"
		(( index++ ))

		# Note: attr only get/sets the user.* namespace!
		# This is exactly what we want to protect security.* trusted.*
		local names=$(attr -ql ${file})
		for name in $names; do
			value=$(attr -qg $name $file)
			eval "${narray}[\"$name\"]=$value"
		done
	done

	return 0
}

__setxattrs()
{
	local file

	if [[ "$__target_is_directory" == "no" ]]; then
		# No need to loop over one source file!
		for name in "${!__xattr_names_0_[@]}"; do
			attr -q -s $name -V ${__xattr_names_0_[$name]} $__target
		done
	else
		local index=0
		for file in "${__source_files[@]}"; do
			local f=${file##*/}
			local narray="__xattr_names_${index}_"
			(( index++ ))
			eval "for name in "\${!${narray}[@]}"; do attr -q -s \$name -V \${${narray}[\$name]} ${__target}/${f} ; done"
		done
	fi
}

if [[ -x /bin/attr ]]; then
	# We need to declare all the associative arrays we'll use globally
	# We can't possibly need more than there are parameters -- overkill!
	index=0
	for i in "$@"; do
		narray="__xattr_names_${index}_"
		(( index++ ))
		eval "declare -A ${narray}"
	done

	__getxattrs "$@"
fi


# Use the full path to the real install to avoid calling ourselves
/usr/bin/install "$@"

if [[ -x /bin/attr ]]; then
	__setxattrs
fi