cloud-initramfs-updateroot 0.40ubuntu1 / usr / share / initramfs-tools / scripts / init-bottom / updateroot

#!/bin/sh
#  Copyright, 2016 Scott Moser <smoser@ubuntu.com>
#
#  This program 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.
#
#  This program 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 this program.  If not, see
#    <http://www.gnu.org/licenses/>.
VERBOSITY="1"

prereqs() {
	local o="/scripts/init-bottom/overlayroot"  p=""
	# basically we run after overlayroot but do not depend on it
	for p in "$DESTDIR/" ""; do
		[ -e "$p$o" ] && echo "overlayroot" && return 0
	done
}

[ "$1" != "prereqs" ] || { prereqs; exit; }

setf() {
	# setf 0|1
	#  set pathname expansion (-f) off or on
	#     off is an alias for 0
	#     on is an alias for 1
	#  stores the current setting in the unscoped variable 'setf'
	#  returns the previous setting:
	#     0 if pathname expansion was off
	#     1 if pathname expansion was on
	# setf restore [setting]
	#  restore pathname expansion to 'setting'.
	#  if setting is not provided, defaults to variable 'setf'
	if [ "$1" = "restore" ]; then
		local val=${2:-${setf:-"-"}}
		[ "$val" = "0" ] && val="-" || val="+"
		set ${val}f
		return
	fi

	local f="" n="0" d=/ r="1"
	setf="+"
	for f in "$d/"*; do
		[ $n -gt 1 ] && break
		n=$(($n+1))
	done
	[ $n -eq 1 -a "$f" = "$d/*" ] && setf="-" && r="0"
	case "$1" in
		off|0) set -f;;
		on|1) set +f;;
	esac
	return $r
}

debug() {
	local v=$1
	shift
	[ $v -lt $VERBOSITY ] && return 0
	echo "::" "$@"
}

log_warn() { log_warning_msg "$*"; }

extract_urls() {
	local target="$1" url="" zopt="" script="" fails="" ret=""
	shift
	for url in "$@"; do
		case "$url" in
			*.tar.gz|*.tgz) zopt="z";;
			*.tar.xz|*.txz) zopt="J";;
			*) zopt="";;
		esac
		debug 1 "# updateroot [$zopt] $url"
		wget "$url" -O - | tar -C "$target" -xp${zopt}f -
	done
	if [ ! -d "$target/.updateroot" ]; then
		return 0
	fi

	fails=0
	setf on; set -- "$target/.updateroot/"*; setf restore
	for script in "$@"; do
		[ -f "$script" -a -x "$script" ] || continue
		debug 1 "running ${script#$target} in target root"
		chroot "$target" "${script#$target}" || {
			fails=$(($fails+1))
			ret=$?
			log_warn "script '${script#$target/}' exited $ret"
		}
	done
	[ $fails -eq 0 ]
}

apply_updateroot() {
	local rootmnt="$1" cmdline="$2" ret=""
	local cmdline urls
	if [ "$cmdline" = "" ]; then
		if ! read cmdline < /proc/cmdline; then
			log_warn "no /proc/cmdline?"
			return 1
		fi
	fi
	setf off; set -- $cmdline; setf restore
	for tok in "$@"; do
		case "$tok" in
			updateroot=http://*) urls="${urls} ${tok#*=}";;
		esac
	done
	urls=${urls# }

	setf off; set -- $urls; setf restore
	if [ $# -eq 0 ]; then
		debug 1 "no updateroot urls configured in cmdline"
		return 0
	fi

	if ! configure_networking; then
		log_warn "failed configuring networking [$?]"
		return 1
	fi

	# only mount rw if not already rw
	local need_remount="false" ret=0 created=true
	local tfile="$rootmnt/.updateroot.touch"
	[ -e "$tfile" ] || created=false
	if ! ( : >> "$tfile" ) >/dev/null 2>&1; then
		mount -o remount,rw "$rootmnt"
		ret=$?
		if $created; then
			rm -f "$tfile"
		fi
		if [ $ret -ne 0 ]; then
			log_warn "failed mount '$rootmnt' as rw [$ret]."
			return 1;
		fi
		need_remount="true"
	fi
	
	extract_urls "$rootmnt" "$@"
	ret=$?

	if $need_remount; then
		mount -o remount,ro "$rootmnt" || {
			log_warn "failed remounting root '$rootmnt' as ro [$?]!"
			return 1
		}
	fi

	return $ret
}

. /scripts/functions

apply_updateroot "$rootmnt"

# vi: ts=4 noexpandtab