#!/bin/ksh
#
# $OpenBSD: syspatch.sh,v 1.120 2017/08/02 05:58:29 ajacoutot Exp $
#
# Copyright (c) 2016, 2017 Antoine Jacoutot <ajacoutot@openbsd.org>
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

set -e
umask 0022

sp_err()
{
	echo "${1}" 1>&2 && return ${2:-1}
}

usage()
{
	sp_err "usage: ${0##*/} [-c | -l | -R | -r]"
}

apply_patch()
{
	local _edir _file _files _patch=$1 _ret=0 _s _upself=false
	[[ -n ${_patch} ]]

	_edir=${_TMP}/${_patch}

	fetch_and_verify "syspatch${_patch}.tgz"

	trap '' INT
	echo "Installing patch ${_patch##${_OSrev}-}"
	install -d ${_edir} ${_PDIR}/${_patch}

	${_BSDMP} && _s="-s /^bsd$//" || _s="-s /^bsd.mp$//"
	_files="$(tar -xvzphf ${_TMP}/syspatch${_patch}.tgz -C ${_edir} ${_s})"

	checkfs ${_files}
	create_rollback ${_patch} "${_files}"

	for _file in ${_files}; do
		((_ret == 0)) || break
		if [[ ${_file} == @(bsd|bsd.mp) ]]; then
			install_kernel ${_edir}/${_file} || _ret=$?
		else
			[[ ${_file} == usr/sbin/syspatch ]] && _upself=true
			install_file ${_edir}/${_file} /${_file} || _ret=$?
		fi
	done

	if ((_ret != 0)); then
		sp_err "Failed to apply patch ${_patch##${_OSrev}-}" 0
		rollback_patch; return ${_ret}
	fi
	# don't fill up /tmp when installing multiple patches at once; non-fatal
	rm -rf ${_edir} ${_TMP}/syspatch${_patch}.tgz
	trap exit INT

	${_upself} && sp_err "syspatch updated itself, run it again to install \
missing patches" 2
}

# quick-and-dirty filesystem status and size checks:
# - assume old files are about the same size as new ones
# - ignore new (nonexistent) files
# - ignore rollback tarball: create_rollback() will handle the failure
# - compute total size of all files per fs, simpler and less margin for error
# - if we install a kernel, double /bsd size (duplicate it in the list) when
#   /bsd.syspatchXX is not present (create_rollback will copy it from /bsd)
checkfs()
{
	local _d _dev _df _files="${@}" _ret _sz
	[[ -n ${_files} ]]

	if echo "${_files}" | grep -Eq '(^|[[:blank:]]+)bsd([[:blank:]]+|$)'
	then
		[[ -f /bsd.syspatch${_OSrev} ]] || _files="bsd ${_files}"
	fi

	set +e # ignore errors due to:
	# - nonexistent files (i.e. syspatch is installing new files)
	# - broken interpolation due to bogus devices like remote filesystems
	eval $(cd / &&
		stat -qf "_dev=\"\${_dev} %Sd\" %Sd=\"\${%Sd:+\${%Sd}\+}%Uz\"" \
			${_files}) 2>/dev/null || _ret=$?
	set -e
	[[ ${_ret} == 127 ]] && sp_err "Remote filesystem, aborting" 

	for _d in $(printf '%s\n' ${_dev} | sort -u); do
		mount | grep -v read-only | grep -q "^/dev/${_d} " ||
			sp_err "Read-only filesystem, aborting"
		_df=$(df -Pk | grep "^/dev/${_d} " | tr -s ' ' | cut -d ' ' -f4)
		_sz=$(($((_d))/1024))
		((_df > _sz)) || sp_err "No space left on ${_d}, aborting"
	done
}

create_rollback()
{
	# XXX annotate new files so we can remove them if we rollback?
	local _file _patch=$1 _rbfiles _ret=0 _s
	[[ -n ${_patch} ]]
	shift
	local _files="${@}"
	[[ -n ${_files} ]]

	for _file in ${_files}; do
		if [[ ${_file} == bsd.mp ]] && ${_BSDMP}; then
			_file=bsd && _s="-s /^bsd$/&.mp/"
		fi
		[[ -f /${_file} ]] || continue
		# only save the original release kernel once
		if [[ ${_file} == bsd && ! -f /bsd.syspatch${_OSrev} ]]; then
			install -FSp /bsd /bsd.syspatch${_OSrev}
		fi
		_rbfiles="${_rbfiles} ${_file}"
	done

	tar -C / -czf ${_PDIR}/${_patch}/rollback.tgz ${_s} ${_rbfiles} ||
		_ret=$?

	if ((_ret != 0)); then
		sp_err "Failed to create rollback patch ${_patch##${_OSrev}-}" 0
		rm -r ${_PDIR}/${_patch}; return ${_ret}
	fi
}

fetch_and_verify()
{
	local _tgz=$1 _title="Get/Verify"
	[[ -n ${_tgz} ]]

	[[ -t 0 ]] || echo "${_title} ${_tgz}"
	unpriv -f "${_TMP}/${_tgz}" ftp -VD "${_title}" -o "${_TMP}/${_tgz}" \
		"${_MIRROR}/${_tgz}"

	(cd ${_TMP} && sha256 -qC ${_TMP}/SHA256 ${_tgz})
}

install_file()
{
	# XXX handle hard and symbolic links, dir->file, file->dir?
	local _dst=$2 _fgrp _fmode _fown _src=$1
	[[ -f ${_src} && -f ${_dst} ]]

	eval $(stat -f "_fmode=%OMp%OLp _fown=%Su _fgrp=%Sg" ${_src})

	install -DFSp -m ${_fmode} -o ${_fown} -g ${_fgrp} ${_src} ${_dst}
}

install_kernel()
{
	local _kern=$1
	[[ -n ${_kern} ]]

	install -FSp ${_kern} /bsd
}

ls_installed()
{
	local _p
	for _p in ${_PDIR}/${_OSrev}-+([[:digit:]])_+([[:alnum:]_]); do
		[[ -f ${_p}/rollback.tgz ]] && echo ${_p##*/${_OSrev}-}
	done | sort -V
}

ls_missing()
{
	local _c _f _cmd _l="$(ls_installed)" _p _r _sha=${_TMP}/SHA256

	# return inmediately if we cannot reach the mirror server
	[[ -d ${_MIRROR#file://*} ]] ||
		unpriv ftp -MVo /dev/null ${_MIRROR%syspatch/*} >/dev/null

	# don't output anything on stdout to prevent corrupting the patch list;
	# redirect stderr as well in case there's no patch available
	unpriv -f "${_sha}.sig" ftp -MVo "${_sha}.sig" "${_MIRROR}/SHA256.sig" \
		>/dev/null 2>&1 || return 0 # empty directory
	unpriv -f "${_sha}" signify -Veq -x ${_sha}.sig -m ${_sha} -p \
		/etc/signify/openbsd-${_OSrev}-syspatch.pub >/dev/null

	# if no earlier version of all files contained in the syspatch exists
	# on the system, it means a missing set so skip it
	grep -Eo "syspatch${_OSrev}-[[:digit:]]{3}_[[:alnum:]_]+" ${_sha} |
		while read _c; do _c=${_c##syspatch${_OSrev}-} &&
		[[ -n ${_l} ]] && echo ${_c} | grep -qw -- "${_l}" || echo ${_c}
	done | while read _p; do
		_cmd="ftp -MVo - ${_MIRROR}/syspatch${_OSrev}-${_p}.tgz"
		{ unpriv ${_cmd} | tar tzf -; } 2>/dev/null | while read _f; do
			[[ -f /${_f} ]] || continue && echo ${_p} && pkill -u \
				_syspatch -xf "${_cmd}" || true && break
		done
	done | sort -V
}

rollback_patch()
{
	local _edir _file _files _patch _ret=0

	_patch="$(ls_installed | tail -1)"
	[[ -n ${_patch} ]]

	_edir=${_TMP}/${_patch}-rollback
	_patch=${_OSrev}-${_patch}

	trap '' INT
	echo "Reverting patch ${_patch##${_OSrev}-}"
	install -d ${_edir}

	_files="$(tar xvzphf ${_PDIR}/${_patch}/rollback.tgz -C ${_edir})"
	checkfs ${_files} ${_PDIR} # check for read-only /var/syspatch

	for _file in ${_files}; do
		((_ret == 0)) || break
		if [[ ${_file} == @(bsd|bsd.mp) ]]; then
			install_kernel ${_edir}/${_file} || _ret=$?
			# remove the backup kernel if all kernel syspatches have
			# been reverted; non-fatal
			cmp -s /bsd /bsd.syspatch${_OSrev} &&
				rm -f /bsd.syspatch${_OSrev}
		else
			install_file ${_edir}/${_file} /${_file} || _ret=$?
		fi
	done

	((_ret != 0)) || rm -r ${_PDIR}/${_patch} || _ret=$?
	((_ret == 0)) ||
		sp_err "Failed to revert patch ${_patch##${_OSrev}-}" ${_ret}
	rm -rf ${_edir} # don't fill up /tmp when using `-R'; non-fatal
	trap exit INT
}

sp_cleanup()
{
	local _d _k

	# remove non matching release /var/syspatch/ content
	for _d in ${_PDIR}/{.[!.],}*; do
		[[ -e ${_d} ]] || continue
		[[ ${_d##*/} == ${_OSrev}-+([[:digit:]])_+([[:alnum:]]|_) ]] &&
			[[ -f ${_d}/rollback.tgz ]] || rm -r ${_d}
	done

	# remove non matching release backup kernel
	for _k in /bsd.syspatch+([[:digit:]]); do
		[[ -f ${_k} ]] || continue
		[[ ${_k} == /bsd.syspatch${_OSrev} ]] || rm ${_k}
	done
}

unpriv()
{
	local _file=$2 _user=_syspatch

	if [[ $1 == -f && -n ${_file} ]]; then
		>${_file}
		chown "${_user}" "${_file}"
		chmod 0711 ${_TMP}
		shift 2
	fi
	(($# >= 1))

	eval su -s /bin/sh ${_user} -c "'$@'"
}

[[ $@ == @(|-[[:alpha:]]) ]] || usage; [[ $@ == @(|-(c|R|r)) ]] &&
	(($(id -u) != 0)) && sp_err "${0##*/}: need root privileges"

# only run on release (not -current nor -stable)
set -A _KERNV -- $(sysctl -n kern.version |
	sed 's/^OpenBSD \([0-9]\.[0-9]\)\([^ ]*\).*/\1 \2/;q')
((${#_KERNV[*]} > 1)) && sp_err "Unsupported release: ${_KERNV[0]}${_KERNV[1]}"

_OSrev=${_KERNV[0]%.*}${_KERNV[0]#*.}
[[ -n ${_OSrev} ]]

_MIRROR=$(while read _line; do _line=${_line%%#*}; [[ -n ${_line} ]] &&
	print -r -- "${_line}"; done </etc/installurl | tail -1) 2>/dev/null
[[ ${_MIRROR} == @(file|http|https)://*/*[!/] ]] ||
	sp_err "${0##*/}: invalid URL configured in /etc/installurl"
_MIRROR="${_MIRROR}/syspatch/${_KERNV[0]}/$(machine)"

(($(sysctl -n hw.ncpufound) > 1)) && _BSDMP=true || _BSDMP=false
_PDIR="/var/syspatch"
_TMP=$(mktemp -d -p /tmp syspatch.XXXXXXXXXX)

readonly _BSDMP _KERNV _MIRROR _OSrev _PDIR _TMP

trap 'set +e; rm -rf "${_TMP}"' EXIT
trap exit HUP INT TERM

while getopts clRr arg; do
	case ${arg} in
		c) ls_missing ;;
		l) ls_installed ;;
		R) while [[ -n $(ls_installed) ]]; do rollback_patch; done ;;
		r) rollback_patch ;;
		*) usage ;;
	esac
done
shift $((OPTIND - 1))
(($# != 0)) && usage

# default action: apply all patches
if ((OPTIND == 1)); then
	sp_cleanup
	_PATCHES=$(ls_missing)
	for _PATCH in ${_PATCHES}; do
		apply_patch ${_OSrev}-${_PATCH}
	done
	# in case a patch added a new directory (install -D)
	if [[ -n ${_PATCHES} ]]; then
		mtree -qdef /etc/mtree/4.4BSD.dist -p / -U >/dev/null
		[[ ! -f /var/sysmerge/xetc.tgz ]] ||
			mtree -qdef /etc/mtree/BSD.x11.dist -p / -U >/dev/null
	fi
fi