add chroot-tools/distcc-tool; it is not used yet though

1 files changed, 252 insertions, 0 deletions

diff --git a/src/chroot-tools/distcc-tool b/src/chroot-tools/distcc-tool
new file mode 100755
index 0000000..840a5aa
--- /dev/null
+++ b/src/chroot-tools/distcc-tool
@@ -0,0 +1,252 @@
+#!/bin/bash
+# -*- tab-width: 4; sh-basic-offset: 4 -*-
+# distcc-tool
+
+# Copyright 2013 Luke Shumaker
+#
+# This file is part of Parabola.
+#
+# Parabola is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Parabola 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 Parabola. If not, see <http://www.gnu.org/licenses/>.
+
+# This program has very few dependencies:
+#  - bash: I don't know what version, I use fairly modern features
+#  - socat
+#  - cat: any version
+#  - grep: any version
+#  - mkdir: any version
+#  - rm: any version
+#  - sed: any version
+#  - sleep: any version
+# On Parabola, this means the packages:
+#  bash, coreutils, grep, sed, socat
+
+panic() {
+	echo 'panic: malformed call to internal function' >&2
+	exit 1
+}
+
+error() {
+	fmt=$1; shift
+	printf "ERROR: $fmt\n" "$@" >&2
+	exit 1
+}
+
+usage() {
+	echo "Usage: $0 COMMAND [COMMAND-ARGS]"
+	echo "Tool for using distcc within a networkless chroot"
+	echo
+	echo "Commands:"
+	echo '  help                  print this message'
+	echo '  odaemon CHROOTPATH    daemon to run outside of the chroot'
+	echo '  idaemon DISTCC_HOSTS  daemon to run inside of the chroot'
+	echo '  rewrite DISTCC_HOSTS  prints a rewritten version of DISTCC_HOSTS'
+	echo '  client HOST PORT      connects stdio to TCP:$HOST:$PORT'
+	echo 'Commands: for internal use'
+	echo '  server                counterpart to client; spawned by odaemon'
+}
+
+errusage() {
+	if [[ $# -gt 0 ]]; then
+		fmt=$1; shift
+		printf "ERROR: $fmt\n" "$@" >&2
+	fi
+	usage >&2
+	exit 1
+}
+
+main() {
+	local cmd=$1
+	shift
+	case "$cmd" in
+		help)
+			[[ $# -eq 0 ]] || errusage '%s: invalid number of arguments' "$cmd"
+			usage;;
+		odaemon|idaemon|rewrite)
+			[[ $# -eq 1 ]] || errusage '%s: invalid number of arguments' "$cmd"
+			$cmd "$@";;
+		client)
+			[[ $# -eq 2 ]] || errusage '%s: invalid number of arguments' "$cmd"
+			$cmd "$@";;
+		server)
+			[[ $# -eq 0 ]] || errusage '%s: invalid number of arguments' "$cmd"
+			$cmd "$@";;
+		*) errusage 'unknown subcommand: %s' "$cmd";;
+	esac
+}
+
+################################################################################
+# DISTCC_HOSTS parser                                                          #
+################################################################################
+
+# usage: parse_DISTCC_HOSTS true|false DISTCC_HOSTS
+# parses DISTCC_HOSTS and:
+# $1==true : It sets up port forwarding for inside the choot, sleep forever
+# $1==false: Prints a modified version of DISTCC_HOSTS that uses the forwarded
+#            ports that were set up when $1==true.
+parse_DISTCC_HOSTS() {
+	{ [[ $# -eq 2 ]] && { [[ $1 == true ]] || [[ $1 == false ]]; }; } || panic
+	local forward_ports=$1
+	local DISTCC_HOSTS=$2
+
+	local pids=() # child pids
+	local newhosts=()
+	local newport=8000 # next port to be used for port forwarding
+
+	# This is based on the grammar specified in distcc(1)
+	local HOSTSPEC
+	for HOSTSPEC in $(sed 's/#.*//' <<<"$DISTCC_HOSTS"); do
+		case "$HOSTSPEC" in
+			# LOCAL_HOST
+			localhost|localhost/*|--localslots=*|--localslots_cpp=*)
+				# "localhost" runs commands directly, not talking to distccd at
+				# localhost, use an IP or real hostname for that.
+				# So, just pass these through.
+				newhosts+=("$HOSTSPEC")
+				;;
+			# SSH_HOST
+			*@*)
+				# SSH_HOST doesn't allow custom port numbers, and even if it
+				# did, ssh would complain about MITM.  Instead, we configure an
+				# ssh ProxyCommand so that ssh works fine.
+				newhosts+=("$HOSTSPEC")
+				;;
+			# GLOBAL_OPTION
+			--*)
+				# pass these through
+				newhosts+=("$HOSTSPEC")
+				;;
+			# ZEROCONF
+			+zeroconf)
+				error "$0 does not support the +zeroconf option"
+				exit 1
+				;;
+			# TCP_HOST or OLDSTYLE_TCP_HOST
+			*)
+				declare HOSTID= PORT= LIMIT= OPTIONS=
+				if [[ $HOSTSPEC =~ ^([^:/]+)(:([0-9]+))?(/([0-9]+))?(,.*)?$ ]]; then
+					# TCP_HOST
+					HOSTID=${BASH_REMATCH[1]}
+					PORT=${BASH_REMATCH[3]}
+					LIMIT=${BASH_REMATCH[5]}
+					OPTIONS=${BASH_REMATCH[6]}
+				elif [[ $HOSTSPEC =~ ^([^:/]+)(/([0-9]+))?(:([0-9]+))?(,.*)?$ ]]; then
+					# OLDSTYLE_TCP_HOST
+					HOSTID=${BASH_REMATCH[1]}
+					LIMIT=${BASH_REMATCH[3]}
+					PORT=${BASH_REMATCH[5]}
+					OPTIONS=${BASH_REMATCH[6]}
+				else
+					error "Could not parse HOSTSPEC: %s" "$HOSTSPEC"
+				fi
+
+				# set up port forwaring
+				if $forward_ports; then
+					socat TCP-LISTEN:${newport},fork SYSTEM:"$0 client $HOSTID ${PORT:-3632}" &
+					pids+=($!)
+				fi
+
+				# add the forwarded port
+				local newhost="127.0.0.1:$newport"
+				[[ -z $LIMIT ]] || newhost+="/$LIMIT"
+				[[ -z $OPTIONS ]] || newhost+="$OPTIONS"
+				newhosts+=("$newhost")
+				: $((newport++))
+				;;
+		esac
+	done
+	if $forward_ports; then
+		if [[ -z "${pids[*]}" ]]; then
+			# listen on port 8000, but immediatly close, just so that we are
+			# listening on something
+			socat TCP-LISTEN:${newport},fork SYSTEM:true &
+			pids+=($!)
+		fi
+		trap "kill -- ${pids[*]}" EXIT
+		wait "${pids[@]}"
+	else
+		printf '%s\n' "${newhosts[*]}"
+	fi
+}
+
+################################################################################
+# Port forwarding primitives                                                   #
+################################################################################
+
+# Usage: server
+# Reads "host port" from the first line of stdin, then connects stdio to the
+# specified TCP socket.
+server() {
+	[[ $# -eq 0 ]] || panic
+	while read -r host port; do
+		socat STDIO TCP:"$host:$port"
+		break
+	done
+}
+
+# Usage: client HOST PORT
+# For usage inside of a chroot. It talks through the UNIX-domain socket to an
+# instance of `server` outside, in order to connect stdio to the specified TCP
+# socket.
+client() {
+	[[ $# -eq 2 ]] || panic
+	local file=/socket
+	{ printf '%s\n' "$*"; cat; } | socat UNIX-CONNECT:"$file" STDIO
+}
+
+################################################################################
+# High-level routines                                                          #
+################################################################################
+
+# Usage: configure_ssh
+# Edits ~/.ssh/config to use `client` as a ProxyCommand so that ssh can work
+# inside of the chroot.
+configure_ssh() {
+	[[ $# -eq 0 ]] || panic
+	if ! grep "^\s*ProxyCommand $0 client" ~/.ssh/config &>/dev/null; then
+		[[ -d ~/.ssh ]] || mkdir ~/.ssh
+		echo 'Host *' >> ~/.ssh/config
+		echo "    ProxyCommand $0 client %h %p" >> ~/.ssh/config
+	fi
+}
+
+# Usage: idaemon DISTCC_HOSTS
+# Sets things up inside of the chroot to forward distcc hosts out.
+# It configures an ssh ProxyCommand.
+idaemon() {
+	[[ $# -eq 1 ]] || panic
+	local DISTCC_HOSTS=$1
+
+	configure_ssh
+
+	parse_DISTCC_HOSTS true "$DISTCC_HOSTS"
+}
+
+# Usage: odaemon CHROOTPATH
+# Listens on "$CHROOTPATH/socket" and spawns a `server` for each new connection.
+odaemon() {
+	[[ $# -eq 1 ]] || panic
+	local chrootpath=$1
+
+	trap "rm -f '$chrootpath/socket'" EXIT
+	socat UNIX-LISTEN:"$chrootpath/socket",fork SYSTEM:"$0 server"
+}
+
+# Usage: rewrite DISTCC_HOSTS
+# Prints a modified version of DISTCC_HOSTS for inside the chroot.
+rewrite() {
+	[[ $# -eq 1 ]] || panic
+	parse_DISTCC_HOSTS false "$1"
+}
+
+main "$@"