#!/bin/sh -f
#
# Copyright (c) 2009
# Dominic Fandrey <kamikaze@bsdforen.de>
#
# 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.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
#

readonly version=1.1.1
readonly name=uma

# Return value.
errno=0
# Allow things to fail properly by ignoring SIGINT in the main process.
trap '' int

# Used to activate verbose output.
verbose=
# Will be set if files are locally available.
local=

vardir="%%VAR%%"
lock="$vardir/run/$name.lock"
lockpid="$vardir/run/$name.pid"
identpid="$vardir/run/$name.ident.pid"
conf="%%PREFIX%%/etc/$name.conf"

# Use line breaks as a delimiter.
IFS='
'
# Timezone UTC for age comparisons.
export TZ=UTC

# The bit position of errors.
readonly ERR_LOCK=0
readonly ERR_ARG=1
readonly ERR_FETCH_PORTS=2
readonly ERR_FETCH_VULNDB=3
readonly ERR_FETCH_INDEX=4
readonly ERR_EXTRACT_PORTS=5
readonly ERR_UPDATE_PORTS=6

#
# Get environment variables.
#

# Load the configuration file if present.
if [ -e "$conf" ]; then
	. "$conf"
fi

# Local index location.
: ${PKG_INDEX="$vardir/db/uma/FTPINDEX"}
: ${FTP_TIMEOUT=60}

# Logic from src/usr.sbin/pkg_install/add/main.c, plus the possibility to
# override the architecture with ARCH.
: ${PACKAGEROOT="ftp://ftp.freebsd.org"}
: ${ARCH="$(uname -m)"}
branch="$(uname -r | tr '[:upper:]' '[:lower:]')"
number="${branch%%.*}"
branch="${branch##*-}"
case "$branch" in
	release)
		branch=$number-$branch
	;;
	stable|current)
		branch=${number%%.*}-$branch
	;;
	*)
		# Fallback to stable for prerelease and the like.
		branch=${number%%.*}-stable
	;;
esac
: ${BRANCH=$branch}
: ${PACKAGESITE="$PACKAGEROOT/pub/FreeBSD/ports/$ARCH/packages-$BRANCH/Latest"}
packagetree="${PACKAGESITE%/*?}"
ftp="${PACKAGESITE#*://}"
ftp="${ftp%%/*}"

#
# Generate PACKAGESITE_MIRRORS if only PACKAGEROOT_MIRRORS are given.
# Note that PACKAGEROOT_MIRRORS and PACKAGESITE_MIRRORS are supposed to be
# a ";" or line feed separated list. Semicolons will be converted to line
# feeds in any case.
#

# Set PACKAGEROOT_MIRRORS if not set.
if [ -z "$PACKAGEROOT_MIRRORS" ]; then
	PACKAGEROOT_MIRRORS=
	for i in $(jot 14); {
		PACKAGEROOT_MIRRORS="${PACKAGEROOT_MIRRORS:+$PACKAGEROOT_MIRRORS$IFS}ftp://ftp$i.FreeBSD.org"
	}
fi

# Convert semicolon in PACKAGEROOT_MIRRORS.
PACKAGEROOT_MIRRORS="$(echo "$PACKAGEROOT_MIRRORS" | sed "s/;/\\$IFS/g")"
# Build PACKAGESITE_MIRRORS.
if [ -z "${PACKAGESITE_MIRRORS}" ]; then
	PACKAGESITE_MIRRORS=
	for MIRROR in $PACKAGEROOT_MIRRORS; {
		PACKAGESITE_MIRRORS="${PACKAGESITE_MIRRORS:+$PACKAGESITE_MIRRORS$IFS}$MIRROR/pub/FreeBSD/ports/$ARCH/packages-$BRANCH/Latest"
	}
fi
# Convert semicolon in PACKAGESITE_MIRRORS.
PACKAGESITE_MIRRORS="$(echo "$PACKAGESITE_MIRRORS" | sed "s/;/\\$IFS/g")"

# Remove duplicates.
PACKAGEROOT_MIRRORS="$(echo "$PACKAGEROOT_MIRRORS" | sort -u)"
PACKAGESITE_MIRRORS="$(echo "$PACKAGESITE_MIRRORS" | sort -u)"

# Determine portsdir
portsdir=$(make -V PORTSDIR -f /usr/share/mk/bsd.port.mk 2> /dev/null)
portsdir="${portsdir:-%%PORTS%%}"

export ARCH BRANCH PKG_INDEX FTP_TIMEOUT PACKAGEROOT PACKAGESITE
export PACKAGEROOT_MIRRORS PACKAGESITE_MIRRORS

#
# This function is called by a trap when the script exits in verbose mode.
# It reads errno to construct error messages.
#
# @param errno
#	The exit status of the script.
#
verbose() {
	if [ $(($errno >> $ERR_LOCK & 1)) -eq 1 ]; then
		echo "ERROR($((1 << $ERR_LOCK))): Lock owned by someone else."
	fi
	if [ $(($errno >> $ERR_ARG & 1)) -eq 1 ]; then
		echo "ERROR($((1 << $ERR_ARG))): An unknown parameter was supplied."
	fi
	if [ $(($errno >> $ERR_FETCH_PORTS & 1)) -eq 1 ]; then
		echo "ERROR($((1 << $ERR_FETCH_PORTS))): Fetching the ports tree failed."
	fi
	if [ $(($errno >> $ERR_FETCH_VULNDB & 1)) -eq 1 ]; then
		echo "ERROR($((1 << $ERR_FETCH_VULNDB))): Fetching security database failed."
	fi
	if [ $(($errno >> $ERR_FETCH_INDEX & 1)) -eq 1 ]; then
		echo "ERROR($((1 << $ERR_FETCH_INDEX))): Fetching remote INDEX failed."
	fi
	if [ $(($errno >> $ERR_EXTRACT_PORTS & 1)) -eq 1 ]; then
		echo "ERROR($((1 << $ERR_EXTRACT_PORTS))): Extracting the ports tree failed."
	fi
	if [ $(($errno >> $ERR_UPDATE_PORTS & 1)) -eq 1 ]; then
		echo "ERROR($((1 << $ERR_UPDATE_PORTS))): Updating the ports tree failed."
	fi
}

#
# This function spawns a process that takes over a lock.
#
# @param pid
#	The PID of the process that requested the lock.
# @param lock
#	The location of the lock file.
# @param lockpid
#	The location of the PID file for the lock holding process.
#
secureLock() {
	lockf "$lock" sh -c "
		trap 'exit 0' term
		echo '$pid' > '$lock'
		echo \"\$\$\" > '$lockpid'
		trap 'rm \"$lockpid\"; exit 0' EXIT
		while kill -0 '$pid' 2> /dev/null; do
			sleep 2
		done
	" 2> /dev/null &
}

#
# Checks whether the currently requesting process holds the lock.
#
# @param pid
#	The PID of the process that requested the lock.
# @param lock
#	The location of the lock file.
# @return
#	Returns 0 if the lock is held for the requesting process or 1
#	if the lock is missing or owned by another process.
#
hasLock() {
	test "$pid" -eq "$(cat "$lock" 2> /dev/null)" 2> /dev/null
	return $?
}

#
# Creates a lock for the requesting process.
# 
# @param pid
#	The PID of the process that requested the lock.
# @param lock
#	The location of the lock file.
# @param lockpid
#	The location of the PID file for the lock holding process.
# @param portsdir
#	The location of the FreeBSD ports tree.
# @return
#	Returns 0 on success, 1 on failure.
#
lock() {
	local location

	# The requestor already holds the lock.
	hasLock && return 0

	# The process requesting the lock does not exist.
	kill -0 "$pid" 2> /dev/null || return 1 $(errno=1)

	# Follow symlinks
	location="$(pwd)"
	if cd "$portsdir" && portsdir="$(pwd -P)"; then
		# Portsdir exists, so we can test for make activity. This
		# does not cover all cases, but it covers a lot.
		if fstat "$portsdir" | awk '{print $2}' | grep -q make; then
			errno=1
			return 1
		fi
	fi
	cd "$location"

	# Try acquiring the lock.
	lockf -st 0 "$lock" "$0" secure $pid 2> /dev/null || return 1 $(errno=1)
	# Wait until the locking process is properly set up.
	while ! [ -e "$lockpid" -a -e "$lock" ]; do
		sleep 0.1
	done
	return 0
}

#
# Frees a lock unless it is held for another process than the requestor.
# 
# @param lock
#	The location of the lock file.
# @param lockpid
#	The location of the PID file for the lock holding process.
# @return
#	Returns 0 on success, 1 on failure.
#
unlock() {
	if hasLock; then
		# Free the lock.
		kill -TERM "$(cat "$lockpid")"
		# Wait for the locking process to clean up.
		while [ -e "$lockpid" -o -e "$lock" ]; do
			sleep 0.1
		done
		return 0
	else
		errno=1
		return 1
	fi
}

#
# Prints the command and available parameters.
#
# @param name
#	The name of the script.
# @param version
#	The version of the script.
#
printHelp() {
	echo "$name v$version
usage:
	$name [-hv] [pid] [fetch] [extract] [update] [...]
	$name [-hv] [pid] fetch [ports] [audit] [ftpindex]
	$name [-hv] [pid] extract [ports]
	$name [-hv] [pid] update [ports]
	$name [-hv] lock [pid]
	$name [-hv] unlock [pid]"
}

#
# Reads the parameters and creates variables that indicates the presence
# of these parameters.
#
# The last numeric value is treated as the requestor PID. It also deals
#
# @param @
#	All parameters to process.
# @param verbose
#	Set to 1 if verbose mode is activated.
# @param cmd_*
#	Set by this function to indicate the presence of a parameter.
#
readParams() {
	local flag
	for flag; {
		# A numerical parameter is the PID.
		if [ "$flag" -eq  "$flag" ] 2> /dev/null; then
			pid="${flag}"
			continue
		fi
	
		# Activate verbose mode for -v.
		case "$flag" in
			-v | --verbose)
				trap 'verbose 1>&2' EXIT
				verbose=1
				continue
			;;
			-h | --help)
				printHelp
				continue
			;;
			-? | --*)
				errno=$((1 << $ERR_ARG))
				exit $errno
			;;
			-*)
				# Split parameters.
				readParams "${flag%${flag#-?}}" "-${flag#-?}"
				continue
			;;
		esac

		# If the variable is not predefined, the command is unknown.
		if eval "test -n \"\${cmd_$flag=1}\""; then
			errno=$((1 << $ERR_ARG))
			exit $errno
		fi
		setvar "cmd_$flag" 1
	}
}

pid="$$"
cmd_lock=
cmd_unlock=
cmd_secure=
cmd_env=
cmd_fetch=
cmd_extract=
cmd_update=
cmd_ports=
cmd_audit=
cmd_ftpindex=
readParams "$@"

#
# Exclusive commands that will cause all others to be ignored, in order
# of priority.
#

if [ -n "$cmd_unlock" ]; then
	unlock
	return $?
fi

if [ -n "$cmd_secure" ]; then
	secureLock
	return $?
fi

if [ -n "$cmd_lock" ]; then
	lock
	return $?
fi

#
# Non-exclusive commands that do not require a lock.
#

if [ -n "$cmd_env" ]; then
	echo "ARCH='$ARCH'"
	echo "BRANCH='$BRANCH'"
	echo "FTP_TIMEOUT='$FTP_TIMEOUT'"
	echo "PACKAGEROOT='$PACKAGEROOT'"
	echo "PACKAGESITE='$PACKAGESITE'"
	echo "PKG_INDEX='$PKG_INDEX'"
	echo "PACKAGEROOT_MIRRORS='$PACKAGEROOT_MIRRORS'"
	echo "PACKAGESITE_MIRRORS='$PACKAGESITE_MIRRORS'"
fi

# Create a local lock if need be.
localLock=
if ! hasLock; then
	localLock=1
	lock || return $?
fi

# Ports tree commands.
if [ -n "$cmd_ports" ]; then
	if [ -n "$cmd_fetch" ]; then
		portsnap fetch || errno="$((1 << $ERR_FETCH_PORTS | $errno))"
	fi
	if [ -n "$cmd_extract" ]; then
		portsnap extract || errno=$((1 << $ERR_EXTRACT_PORTS | $errno))
	fi
	if [ -n "$cmd_update" ]; then
		portsnap update || errno=$((1 << $ERR_UPDATE_PORTS | $errno))
	fi
fi

# Portaudit commands.
if [ -n "$cmd_audit" ]; then
	if [ -n "$cmd_fetch" ]; then
		portaudit -F || errno=$((1 << $ERR_FETCH_VULNDB | $errno))
	fi
fi

# Package index commands.
if [ -n "$cmd_ftpindex" ]; then
	if ! mkdir -p "${PKG_INDEX%/*}" 2> /dev/null; then
		test -n "$verbose" \
			&& echo "The directory ${PKG_INDEX%/*} does not exist and cannot be created!"
		errno=$((1 << $ERR_FETCH_INDEX | $errno))
	elif [ -n "$cmd_fetch" ]; then
		fetch -mo "$PKG_INDEX" "$packagetree/INDEX" \
			|| errno=$((1 << $ERR_FETCH_INDEX | $errno))
	fi
fi


# Free a local lock.
test -n "$localLock" && unlock

return $errno