1#!/bin/sh
2
3# SPDX-License-Identifier: BSD-2-Clause
4#
5# Copyright (c) 2000, Bruce Evans <bde@freebsd.org>
6# Copyright (c) 2018, Jeff Roberson <jeff@freebsd.org>
7#
8# Redistribution and use in source and binary forms, with or without
9# modification, are permitted provided that the following conditions
10# are met:
11# 1. Redistributions of source code must retain the above copyright
12#    notice, this list of conditions and the following disclaimer.
13# 2. Redistributions in binary form must reproduce the above copyright
14#    notice, this list of conditions and the following disclaimer in the
15#    documentation and/or other materials provided with the distribution.
16#
17# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27# SUCH DAMAGE.
28#
29
30usage()
31{
32	echo "usage: genoffset [-o outfile] objfile"
33	exit 1
34}
35
36work()
37(
38    local last off x1 x2 x3 struct field type lastoff lasttype asserts
39
40    echo "#ifndef _OFFSET_INC_"
41    echo "#define _OFFSET_INC_"
42    echo "#if !defined(GENOFFSET) && (!defined(KLD_MODULE) || defined(KLD_TIED))"
43    last=
44    asserts=
45    while read off x1 x2 struct field type x3; do
46	off=$(echo "$off" | sed -E 's/^0+//')
47	if [ "$last" != "$struct" ]; then
48	    if [ -n "$last" ]; then
49		echo "};"
50	    fi
51	    echo "struct ${struct}_lite {"
52	    last=$struct
53	    printf "%b" "\tu_char\tpad_${field}[${off}];\n"
54	else
55	    printf "%b" "\tu_char\tpad_${field}[${off} - (${lastoff} + sizeof(${lasttype}))];\n"
56	fi
57	printf "%b" "\t${type}\t${field};\n"
58	lastoff="$off"
59	lasttype="$type"
60	asserts="${asserts}_SA(${struct}, ${field}, ${off});\n"
61    done <<EOT
62$(${NM:='nm'} ${NMFLAGS} -t d "$1" | grep __assym_offset__ | sed -e 's/__/ /g' | sort -k 4 -k 1 -n)
63EOT
64    echo "};"
65    echo "#define _SA(s,f,o) _Static_assert(__builtin_offsetof(struct s ## _lite, f) == o, \\"
66    printf '\t"struct "#s"_lite field "#f" not at offset "#o)\n'
67    printf "${asserts}"
68    echo "#undef _SA"
69    echo "#endif"
70    echo "#endif"
71)
72
73
74#
75#MAIN PROGGRAM
76#
77use_outfile="no"
78while getopts "o:" option
79do
80	case "$option" in
81	o)	outfile="$OPTARG"
82		use_outfile="yes";;
83	*)	usage;;
84	esac
85done
86shift $((OPTIND - 1))
87case $# in
881)	;;
89*)	usage;;
90esac
91
92if [ "$use_outfile" = "yes" ]
93then
94	work "$1"  3>"$outfile" >&3 3>&-
95else
96	work "$1"
97fi
98
99