#!/bin/bash

# Copyright (C) 2009-2010 Oracle and/or its affiliates. All rights reserved.
# Author: Tim Abbott
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License, version 2.
#
# 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, write to the Free Software
# Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
# 02110-1301, USA.
#
# Not a Contribution for purposes of the Fedora Project Individual Contributor
# License Agreement
#
# Ksplice modprobe wrapper script to use depmod information for the
# running kernel, including Ksplice updates that have been
# cold-applied.

UPTRACK_IN_USE=/var/run/uptrack


# We want to make sure that there are no races between applying an update
# and loading a kernel module as we could end up in a situation where a
# module is loaded by the admin at the exact same time an update patching
# the same target module is loaded, which could lead the Ksplice core
# module to assume the target module is not loaded (and hence does not
# require any live patching), but the target module gets loaded BEFORE we
# had a chance to install the cold patched module on disk, leaving the
# system in a bad state and with unremovable Ksplice updates.
#
# /var/run being accessible to the uptrack client is a built-in assumption
# already in uptrack.
LOCK_PATH=/var/run/.modprobe.ksplice.lock

# If we can create/access this file, we should lock it. Otherwise,
# ignore the file.  This does mean that somebody who has
# CAP_SYS_MODULE will be able to load modules without taking the
# lock.

# Create with 600 permissions
umask 077

if touch ${LOCK_PATH} 2>/dev/null; then
       exec 9> ${LOCK_PATH}
       flock --shared 9
fi

# Restore regular umask
umask 022

# Don't bother with the uptrack modprobe if uptrack isn't is use.
if ! [ -f "$UPTRACK_IN_USE" ] || ! /bin/grep -sq ^ksplice_ /proc/modules; then
    exec -a modprobe "/sbin/modprobe.ksplice-orig" "$@"
fi

# Args based on module-init-tools 3.6.
get_set_version_arg ()
{
    OPTS=$(PATH=/usr/bin:/bin getopt -q -o 'vVC:o:rknqQsclt:aifbwd:' --long "verbose,version,config:,name:,remove,wait,showconfig,autoclean,quiet,show,dry-run,syslog,type:,list,all,ignore-install,ignore-remove,force,force-vermagic,force-modversion,set-version:,dirname,first-time,dump-modversions,use-blacklist" -- "$@") || return 1
    eval set -- "$OPTS"
    while true; do
	case "$1" in
	    --) shift; break;;
	    --set-version) shift; echo "$1"; shift;;
	    *) shift;;
	esac
    done
}

if [ -n "$(get_set_version_arg $@)" ]; then
    # The user passed --set-version; since presumably they explicitly
    # want to use some version other than that of their running
    # kernel, run modprobe with the user's options

    # TODO?: Check if the version is the same as the running kernel's
    # and if so, s/--set-version `uname -r`/--set-version ksplice-`uname -r`/.
    exec -a modprobe "/sbin/modprobe.ksplice-orig" "$@"
fi

VERARGS=
FAKEVERSION=$(/bin/uname -r).ksplice-updates
FAKEMODDIR="/lib/modules/$FAKEVERSION"
if [ -e "$FAKEMODDIR/valid" ]; then
    # If any Ksplice updates are cold-applied, use them
    VERARGS="--set-version $FAKEVERSION"
fi

exec -a modprobe "/sbin/modprobe.ksplice-orig" $VERARGS "$@"