#!/bin/bash

#

#############################################################################

# Copyright (c) 2009 Novell, Inc.

# All Rights Reserved.

#

# This program is free software; you can redistribute it and/or

# modify it under the terms of version 2 of the GNU General Public License as

# published by the Free Software Foundation.

#

# 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, contact Novell, Inc.

#

# To contact Novell about this file by physical or electronic mail,

# you may find current contact information at www.novell.com

#############################################################################

#

# print the mainline / stable commit id this kernel is based on

usage()

{

	echo "Usage: $0 -g <mainline kernel git> [-v] [-f] version"

}

die()

{

	echo "$@" >&2

	exit 1

}

git()

{

	(cd "$git"; command git "$@")

}

rev_parse()

{

	git rev-parse --verify "$@"

}

git=

quiet=-q

force=false

options=$(getopt -n "$0" -o g:vfh --long git:,verbose,force,help -- "$@")

if test $? != 0; then

	usage >&2

	exit 1

fi

eval set -- "$options"

while test $# -gt 0; do

	case "$1" in

	-g | --git)

		git=$2

		shift 2

		;;

	-v | --verbose)

		quiet=

		shift

		;;

	-f | --force)

		force=true

		shift

		;;

	--)

		shift

		break

		;;

	esac

done

if test -z "$git" -o $# -ne 1; then

	usage >&2

	exit 1

fi

base=$1

sanity_check()

{

	if ! $force && ! rev_parse 1da177e4c3^0 >/dev/null; then

		die "$git does not look like Linus' kernel repository"

	fi

}

# hardcoded list of a few -bk snapshots used in the suse kernels,

# generated by the bk-commit script

hardcoded_ids=(

	2.6.8-rc4-bk1   783707a1a3fd16d70938a53dd598f6dcd4a6acd2

	2.6.8-rc4-bk2   da58de4bc4757780df70c71195ced7f4611102ca

	2.6.10-rc3-bk10 9d53e4dd111c4bcb1f55961fce39823e340016f6

	2.6.10-rc3-bk14 0233f53fa39d43e2f923c3485502b0461cecc0d7

	2.6.11-rc1-bk8  f21ec4092851e6d7939d7c2a49ac94947840f789

	2.6.11-rc2-bk1  dea9f2aa018246b995d582b8670b362c9cdc69f4

	2.6.11-rc2-bk2  b82f54f7ca17c0ee66bbbc6216275727beef4645

	2.6.11-rc2-bk3  31d881c779c6b98a306c2b0b6063827fb4076102

	2.6.11-rc2-bk4  0bfe221f282f6050b0e999efa9840f67b4fc4d86

	2.6.11-rc2-bk5  c4eadeb71803d271a4b1c09f976824190e4f1f60

	2.6.11-rc2-bk6  c3dfb72cd40074699d7c0940bb0dab976d764952

	2.6.11-rc2-bk7  c923dd8bf3a6002c27ffc23bd11c5f9d86a779ca

	2.6.11-rc2-bk8  31ae6999d2d740b826610547a0fc72382c8c8985

	2.6.11-rc2-bk9  2db1b65b7049001d1451ab1d678da6136b6bbf1c

	2.6.11-rc2-bk10 b389f3821f284617ea17a11ca750d78d1e1cbfc5

	2.6.11-rc3-bk1  b8a743970378fc8e3206b1b4fcdbecc5f37732f5

	2.6.11-rc3-bk2  f69229f575d96cbd0ba28927b734e11fdfe3b51c

	2.6.11-rc3-bk3  1581782eada791b39ffb9de30b8e88b235d87af7

	2.6.11-rc3-bk4  72aa1a6208693f23aec38d8156f60323c2ef61d4

	2.6.11-rc3-bk5  26815161adef49875c03f19536c2c176d638c151

	2.6.11-rc3-bk6  3d23006057f7aaaf01b53305327d542a72626fe5

	2.6.11-rc3-bk7  f24ad951c5114bcfb587b4f348969c002215a2b4

	2.6.11-rc3-bk8  eeca3f3459cae2a1446b1a9b9b1a2c0805471b21

	2.6.11-rc3-bk9  d007c49cc9d6d0e8542320549e74bdd8bf82ccb4

	2.6.11-rc4-bk2  d14d4021344ded14661bf0507098ac14a6c78051

	2.6.11-rc4-bk3  547b39b5be57eee77e574ce55aef1ea3d9151e54

	2.6.11-rc4-bk4  5ff974d98118d600159788c9637d013df8361fa7

	2.6.11-rc4-bk5  9a7a579e7532dc9c8ca995c0bd247bd8f0c9f696

	2.6.11-rc4-bk6  28ad2df3a4f2471f8de501ec9e1eefca42b08f93

	2.6.11-rc4-bk7  175df1ee8b945ea85682f82112766c029327c9d8

	2.6.11-rc4-bk8  fca717c5fe8afad05b62bd84b1b88076e50df89d

	2.6.11-rc4-bk9  c0d51c67f9c398279a95c5a7df387f2d9a586c98

	2.6.11-rc4-bk10 21e99435aee5b96f9db89bc7b03be98ec3be4fbc

	2.6.11-rc4-bk11 9f459dee9e73e90a0a357e5bf53b4bc56282c1da

	2.6.11-rc5-bk1  6101e24910aee642d8bafe2c8dda3ef739353542

	2.6.11-rc5-bk2  8ad4c6043159b2c80e8a44d45cc134af31bb4b01

	2.6.11-rc5-bk3  54077d3c29a1afba9fe5a0c91f4a24d34083e764

	2.6.11-rc5-bk4  a847f56464f9737ddb11a7e41f63b142b237b776

	2.6.11          1274fcd685ec15f10261f48dc990367c2180d589

)

fetch_from()

{

	local url="git://git.kernel.org/pub/scm/linux/kernel/git/$1"

	local version=$2 refspec

	local name=${1%.git}

	name=${name##**/}

	case "$version" in

	*.* )

		version=v${version}

	esac

	base_id=$(rev_parse "$version^{commit}")

	if test -n "$base_id"; then

		return 0

	fi

	refspec=($(git ls-remote "$url" | \

		sed -rn -e 's@.*(refs/tags/v[1-9][^^]*)$@\1:\1@p' -e \

			"s@.*(refs/heads/master)\$@\\1:upstream/$name@p"))

	case "$version" in

	v*)

		if ! echo "${refspec[@]}" | grep -q "/$version:"; then

			# if we are looking for a v* tag and it is not there,

			# do not bother fetching anything

			return 1

		fi

	esac

	git fetch $quiet "$url" "${refspec[@]}"

	base_id=$(rev_parse "$version^{commit}")

	test -n "$base_id"

}

kernel_version()

{

	local version=$1 major minor micro

	version=${version%%[^0-9.]*}

	local IFS=.

	set -- $version

	major=$1

	minor=$2

	micro=$3

	expr "$major" '*' 65536 '+' "0$minor" '*' 256 + "0$micro"

}

get_base_id()

{

	local base=$1

	base_id=

	for ((i = 0; i < ${#hardcoded_ids[@]}; i += 2)); do

		if test "$base" = "${hardcoded_ids[i]}"; then

			base_id=${hardcoded_ids[i+1]}

			fetch_from "tglx/history.git" "$base_id"

			return

		fi

	done

	if test "$base" = "2.6.12git9"; then

		base=2.6.12-git9

	fi

	case "$base" in

	2.6.*-git*)

		local url="http://www.kernel.org/pub/linux/kernel/v2.6/snapshots"

		base_id=$(curl -f -s "$url/patch-$base.id")

		if test -z "$base_id"; then

			base_id=$(curl -f -s "$url/old/patch-$base.id")

		fi

		if test -n "$base_id"; then

			fetch_from "torvalds/linux-2.6.git" "$base_id"

			return

		fi

	esac

	if test $(kernel_version "$base") -le $(kernel_version 2.6.11); then

		fetch_from "tglx/history.git" "$base"

		if test -n "$base_id"; then

			return

		fi

	fi

	local is_stable=false

	case "$base" in

	[3-9].*.0-rc* | [1-9][0-9].*.0-rc*)

		base=${base/.0-/-}

		;;

	[3-9].*.0 | [1-9][0-9].*.0)

		base=${base%.0}

	esac

	case "$base" in

	2.6.11.*)

		# The history tree has 2.6.11.y up to 2.6.11.5; but there 

		# is no tree for the rest and I don't plan to create any

		base_id=0

		;;

	2.6.*-rt*)

		fetch_from "tip/linux-2.6-tip.git"

		;;

	2.6.*.* | [3-9].*.* | [1-9][0-9].*.* )

		is_stable=true

		if ! fetch_from "stable/linux-stable.git" "$base"; then

			fetch_from "longterm/linux-${base%.*}.y.git" "$base"

		fi

		;;

	2.6.* | [3-9].* | [1-9][0-9].*)

		fetch_from "torvalds/linux.git" "$base"

		;;

	*)

		die "Unexpected kernel version $base"

	esac

	if test -z "$base_id"; then

		case "$base" in

		2.6.*-rt*)

			# not all rt releases are tagged in tip

			base_id=0

			;;

		*-rc* )

			if $is_stable; then

				# RCs for stable are typically not in git

				base_id=0

			fi

			;;

		esac

	fi

}

sanity_check >&2

get_base_id "$base" >&2

if test -z "$base_id"; then

	die "Cannot match $base to commit id"

fi

if test "$base_id" = 0; then

	echo "Warning: no id for $base" >&2

elif ! rev_parse "$base_id^{commit}" >/dev/null; then

	die "internal error: got bogus id $base_id for $base"

fi

echo "$base_id"