#!/bin/sh
#
# Copyright 2022 Michael J. Karels
# Copyright 2014 John-Mark Gurney
# All rights reserved.
#
# 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.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
#
#

# PROVIDE: growfs
# REQUIRE: fsck
# BEFORE: root
# KEYWORD: firstboot

# Grow root partition to fill available space, optionally adding a swap
# partition at the end.  This allows us to distribute an image and
# have it work on essentially any size drive.

# Note that this uses awk(1), and thus will not work if /usr is on a separate
# filesystem.  We need to run early, because there might be not enough free
# space on rootfs for the boot to succeed, and on images we ship - which are
# the primary purpose of this script - there is no separate /usr anyway.

. /etc/rc.subr

name="growfs"
desc="Grow root partition to fill device"
start_cmd="growfs_start"
stop_cmd=":"
rcvar="growfs_enable"

growfs_get_diskdev()
{
	local _search=${1}
	sysctl -b kern.geom.conftxt |
	while read x1 _type _dev line
	do
		if [ "${_type}" = "DISK" -a -n "$(echo ${_search} | grep ${_dev})" ]; then
			echo -n ${_dev}
			break
		fi
	done
}

# Compute upper bound on swap partition size (if added), based on physmem
# and vm.swap_maxpages / 2 (the limit that elicits a warning).
# Rule for swap size based on memory size:
#	up to 4 GB	twice memory size
#	4 GB - 8 GB	8 GB
#	over 8 GB	memory size
growfs_swap_max()
{
	memsize=$(sysctl -n hw.physmem)
	memsizeMB=$(($memsize / (1024 * 1024)))

	if  [ $memsizeMB -lt 4096 ]
	then
		swapmax=$(($memsize * 2))
	elif  [ $memsizeMB -lt 8192 ]
	then
		swapmax=$((8192 * 1024 * 1024))
	else
		swapmax=$memsize
	fi

	pagesize=$(sysctl -n hw.pagesize)
	vm_swap_max=$(($(sysctl -n vm.swap_maxpages) / 2 * $pagesize))

	if [ $swapmax -gt $vm_swap_max ]
	then
		swapmax=$vm_swap_max
	fi
	echo -n "$swapmax"
}

# Find newly-added swap partition on parent device ($1).
growfs_last_swap()
{
	swapdev=$(gpart list $1 | awk '
		$2 == "Name:" { dev = $3 }
		$1 == "type:" && $2 == "freebsd-swap" { swapdev = dev }
		END { print swapdev }
	    ')
	echo -n $swapdev
}

growfs_start()
{
	verbose=0
	echo "Growing root partition to fill device"
	FSTYPE=$(mount -p | awk '{ if ( $2 == "/") { print $3 }}')
	FSDEV=$(mount -p | awk '{ if ( $2 == "/") { print $1 }}')
	case "$FSTYPE" in
	ufs)
		rootdev=${FSDEV#/dev/}
		;;
	zfs)
		pool=${FSDEV%%/*}
		rootdev=$(zpool list -v $pool | awk 'END { print $1 }')
		;;
	*)
		echo "Don't know how to grow root filesystem type: $FSTYPE"
		return
	esac
	if [ x"$rootdev" = x"${rootdev%/*}" ]; then
		# raw device
		rawdev="$rootdev"
	else
		rawdev=$(glabel status | awk -v rootdev=$rootdev 'index(rootdev, $1) { print $3; }')
		if [ x"$rawdev" = x"" ]; then
			echo "Can't figure out device for: $rootdev"
			return
		fi
	fi

	if [ x"diskid" = x"${rootdev%/*}" ]; then
		search=$rootdev
	else
		search=$rawdev
	fi

	diskdev=$(growfs_get_diskdev ${search})
	if [ -z "${diskdev}" ]; then
		diskdev=${rootdev}
	fi

	# Check kenv for growfs_swap_size; if not present,
	# check $growfs_swap_size from /etc/rc.conf.
	# A value of 0 suppresses swap addition,
	# "" (or unset) specifies the default;
	# other values indicate the size in bytes.
	# If default, check whether swap is already in fstab;
	# if so, don't add another.
	addswap=1
	swapsize="$(kenv -q growfs_swap_size 2>/dev/null)"
	case "$swapsize" in
	"0")	addswap=0
		;;
	"")	case "$growfs_swap_size" in
		"0")	addswap=0
			;;
		"")
			if ! awk '
				/^#/ { next }
				$3 == "swap" { exit 1 }
			    ' < /etc/fstab
			then
				addswap=0
			fi
			;;
		*)	swapsize="$growfs_swap_size"
			;;
		esac
		;;
	*)	;;
	esac

	swaplim=$(growfs_swap_max)

	[ $verbose -eq 1 ] && {
		echo "diskdev is $diskdev"
		echo "search is $search"
		echo "swapsize is $swapsize"
		echo "swaplim is $swaplim"
	}

	sysctl -b kern.geom.conftxt | awk '
{
	verbose = 0
	lvl=$1
	device[lvl] = $3
	type[lvl] = $2
	idx[lvl] = $7
	offset[lvl] = $9
	parttype[lvl] = $13
	size[lvl] = $4
	if (verbose) print lvl, type[lvl], $3
	if (type[lvl] == "DISK") {
		disksize = size[lvl]
		if (verbose)
			print "disksize ", disksize
		# Do not add swap on disks under 15 GB (decimal) by default.
		if (addswap == 1 && (size[lvl] > 15000000000 || swapsize > 0))
			doing_swap = 1
		else
			doing_swap = 0
	} else if (type[lvl] == "PART" && $11 == "freebsd-swap" && \
	    int(swapsize) == 0) {
		# This finds swap only if it precedes root, e.g. preceding disk.
		addswap = 0
		doing_swap = 0
		print "swap device exists, not adding swap"
	}
	if (dev == $3) {
		for (i = 1; i <= lvl; i++) {
			# resize
			if (type[i] == "PART") {
				pdev = device[i - 1]
				if (verbose)
					print i, pdev, addswap, disksize, \
					    doing_swap
				swapcmd = ""
				# Allow swap if current root is < 40% of disk.
				if (parttype[i] != "MBR" && doing_swap == 1 && \
				    (size[i] / disksize < 0.4 || \
				    swapsize > 0)) {
					print "Adding swap partition"
					if (int(swapsize) == 0) {
						swapsize = int(disksize / 10)
						if (swapsize > swaplim)
							swapsize = swaplim
					}
					sector = $5
					swapsize /= sector
					if (verbose)
						print "swapsize sectors",
						    swapsize
					align = 4 * 1024 * 1024 / sector

					# Estimate offset for swap; let
					# gpart compute actual start and size.
					# Assume expansion all goes into this
					# partition for MBR case.
					if (parttype[i - 1] == "MBR") {
					    if (verbose)
						print "sz ", size[i - 1], \
						    " off ", offset[i - 1]
					    expand = size[0] - \
						(size[i - 1] + offset[i - 1])
					} else {
					    if (verbose)
						print "sz ", size[i], \
						    " off ", offset[i]
					    expand = size[0] - \
						(size[i] + offset[i])
					}
					if (verbose)
					    print "expand ", expand, \
						" sz ", size[i]
					swapbase = (expand + size[i]) / sector
					swapbase -= swapsize + align
					swapcmd = "gpart add -t freebsd-swap -a " align " -b " int(swapbase) " " pdev " && kenv growfs_swap_pdev=" pdev " >/dev/null; "
					if (verbose)
						swapcmd = "set -x; gpart show; " swapcmd
				}
				cmd[i] = swapcmd "gpart resize -i " idx[i] " " pdev
				if (parttype[i] == "GPT")
					cmd[i] = "gpart recover " pdev " ; " cmd[i]
			} else if (type[i] == "LABEL") {
				continue
			} else {
				print "unhandled type: " type[i]
				exit 1
			}
		}
		for (i = 1; i <= lvl; i++) {
			if (cmd[i])
				system(cmd[i])
		}
		exit 0
	}
}' dev="$search" addswap="$addswap" swapsize="$swapsize" swaplim="$swaplim"
	gpart commit "$diskdev" 2> /dev/null
	case "$FSTYPE" in
	ufs)
		growfs -y /dev/"$rootdev"
		;;
	zfs)
		zpool online -e $pool $rootdev
		;;
	esac

	# Get parent device of swap partition if one was added;
	# if so, find swap device and label it.
	pdev=$(kenv -q growfs_swap_pdev)
	if [ -n "$pdev" ]
	then
		dev=$(growfs_last_swap "$pdev")
		if [ -z "$dev" ]
		then
			echo "Swap partition not found on $pdev"
			exit 0
		fi
		glabel label -v growfs_swap $dev
	fi
}

load_rc_config $name
run_rc_command "$1"
