1#!/bin/bash
2# SPDX-License-Identifier: GPL-2.0-only
3
4# objdiff - a small script for validating that a commit or series of commits
5# didn't change object code.
6#
7# Copyright 2014, Jason Cooper <jason@lakedaemon.net>
8#
9
10# usage example:
11#
12# $ git checkout COMMIT_A
13# $ <your fancy build command here>
14# $ ./scripts/objdiff record path/to/*.o
15#
16# $ git checkout COMMIT_B
17# $ <your fancy build command here>
18# $ ./scripts/objdiff record path/to/*.o
19#
20# $ ./scripts/objdiff diff COMMIT_A COMMIT_B
21# $
22
23# And to clean up (everything is in .tmp_objdiff/*)
24# $ ./scripts/objdiff clean all
25#
26# Note: 'make mrproper' will also remove .tmp_objdiff
27
28SRCTREE=$(cd $(git rev-parse --show-toplevel 2>/dev/null); pwd)
29
30if [ -z "$SRCTREE" ]; then
31	echo >&2 "ERROR: Not a git repository."
32	exit 1
33fi
34
35TMPD=$SRCTREE/.tmp_objdiff
36
37usage() {
38	echo >&2 "Usage: $0 <command> <args>"
39	echo >&2 "  record    <list of object files or directories>"
40	echo >&2 "  diff      <commitA> <commitB>"
41	echo >&2 "  clean     all | <commit>"
42	exit 1
43}
44
45get_output_dir() {
46	dir=${1%/*}
47
48	if [ "$dir" = "$1" ]; then
49		dir=.
50	fi
51
52	dir=$(cd $dir; pwd)
53
54	echo $TMPD/$CMT${dir#$SRCTREE}
55}
56
57do_objdump() {
58	dir=$(get_output_dir $1)
59	base=${1##*/}
60	stripped=$dir/${base%.o}.stripped
61	dis=$dir/${base%.o}.dis
62
63	[ ! -d "$dir" ] && mkdir -p $dir
64
65	# remove addresses for a cleaner diff
66	# http://dummdida.tumblr.com/post/60924060451/binary-diff-between-libc-from-scientificlinux-and
67	$STRIP -g $1 -R __bug_table -R .note -R .comment -o $stripped
68	$OBJDUMP -D $stripped | sed -e "s/^[[:space:]]\+[0-9a-f]\+//" -e "s:^$stripped:$1:" > $dis
69}
70
71dorecord() {
72	[ $# -eq 0 ] && usage
73
74	FILES="$*"
75
76	CMT="`git rev-parse --short HEAD`"
77
78	STRIP="${CROSS_COMPILE}strip"
79	OBJDUMP="${CROSS_COMPILE}objdump"
80
81	for d in $FILES; do
82		if [ -d "$d" ]; then
83			for f in $(find $d -name '*.o')
84			do
85				do_objdump $f
86			done
87		else
88			do_objdump $d
89		fi
90	done
91}
92
93dodiff() {
94	[ $# -ne 2 ] && [ $# -ne 0 ] && usage
95
96	if [ $# -eq 0 ]; then
97		SRC="`git rev-parse --short HEAD^`"
98		DST="`git rev-parse --short HEAD`"
99	else
100		SRC="`git rev-parse --short $1`"
101		DST="`git rev-parse --short $2`"
102	fi
103
104	DIFF="`which colordiff`"
105
106	if [ ${#DIFF} -eq 0 ] || [ ! -x "$DIFF" ]; then
107		DIFF="`which diff`"
108	fi
109
110	SRCD="$TMPD/$SRC"
111	DSTD="$TMPD/$DST"
112
113	if [ ! -d "$SRCD" ]; then
114		echo >&2 "ERROR: $SRCD doesn't exist"
115		exit 1
116	fi
117
118	if [ ! -d "$DSTD" ]; then
119		echo >&2 "ERROR: $DSTD doesn't exist"
120		exit 1
121	fi
122
123	$DIFF -Nurd $SRCD $DSTD
124}
125
126doclean() {
127	[ $# -eq 0 ] && usage
128	[ $# -gt 1 ] && usage
129
130	if [ "x$1" = "xall" ]; then
131		rm -rf $TMPD/*
132	else
133		CMT="`git rev-parse --short $1`"
134
135		if [ -d "$TMPD/$CMT" ]; then
136			rm -rf $TMPD/$CMT
137		else
138			echo >&2 "$CMT not found"
139		fi
140	fi
141}
142
143[ $# -eq 0 ] &&	usage
144
145case "$1" in
146	record)
147		shift
148		dorecord $*
149		;;
150	diff)
151		shift
152		dodiff $*
153		;;
154	clean)
155		shift
156		doclean $*
157		;;
158	*)
159		echo >&2 "Unrecognized command '$1'"
160		exit 1
161		;;
162esac
163