1#!/bin/bash
2# Copyright 2020 The Go Authors. All rights reserved.
3# Use of this source code is governed by a BSD-style
4# license that can be found in the LICENSE file.
5
6# Do not run directly; run build.sh, which runs this in Docker.
7# This script builds goboringcrypto's syso, after boringssl has been built.
8
9export TERM=dumb
10
11set -e
12set -x
13id
14date
15export LANG=C
16unset LANGUAGE
17
18case $(uname -m) in
19x86_64)  export GOARCH=amd64 ;;
20aarch64) export GOARCH=arm64 ;;
21*)
22	echo 'unknown uname -m:' $(uname -m) >&2
23	exit 2
24esac
25
26export CGO_ENABLED=0
27
28# Build and run test C++ program to make sure goboringcrypto.h matches openssl/*.h.
29# Also collect list of checked symbols in syms.txt
30set -e
31cd /boring/godriver
32cat >goboringcrypto.cc <<'EOF'
33#include <cassert>
34#include "goboringcrypto0.h"
35#include "goboringcrypto1.h"
36#define check_size(t) if(sizeof(t) != sizeof(GO_ ## t)) {printf("sizeof(" #t ")=%d, but sizeof(GO_" #t ")=%d\n", (int)sizeof(t), (int)sizeof(GO_ ## t)); ret=1;}
37#define check_func(f) { auto x = f; x = _goboringcrypto_ ## f ; }
38#define check_value(n, v) if(n != v) {printf(#n "=%d, but goboringcrypto.h defines it as %d\n", (int)n, (int)v); ret=1;}
39int main() {
40int ret = 0;
41#include "goboringcrypto.x"
42return ret;
43}
44EOF
45
46cat >boringx.awk <<'EOF'
47BEGIN {
48	exitcode = 0
49}
50
51# Ignore comments, #includes, blank lines.
52/^\/\// || /^#/ || NF == 0 { next }
53
54# Ignore unchecked declarations.
55/\/\*unchecked/ { next }
56
57# Check enum values.
58!enum && ($1 == "enum" || $2 == "enum") && $NF == "{" {
59	enum = 1
60	next
61}
62enum && $1 == "};" {
63	enum = 0
64	next
65}
66enum && /^}.*;$/ {
67	enum = 0
68	next
69}
70enum && NF == 3 && $2 == "=" {
71	name = $1
72	sub(/^GO_/, "", name)
73	val = $3
74	sub(/,$/, "", val)
75	print "check_value(" name ", " val ")" > "goboringcrypto.x"
76	next
77}
78enum {
79	print FILENAME ":" NR ": unexpected line in enum: " $0 > "/dev/stderr"
80	exitcode = 1
81	next
82}
83
84# Check struct sizes.
85/^typedef struct / && $NF ~ /^GO_/ {
86	name = $NF
87	sub(/^GO_/, "", name)
88	sub(/;$/, "", name)
89	print "check_size(" name ")" > "goboringcrypto.x"
90	next
91}
92
93# Check function prototypes.
94/^(const )?[^ ]+ \**_goboringcrypto_.*\(/ {
95	name = $2
96	if($1 == "const")
97		name = $3
98	sub(/^\**_goboringcrypto_/, "", name)
99	sub(/\(.*/, "", name)
100	print "check_func(" name ")" > "goboringcrypto.x"
101	print name > "syms.txt"
102	next
103}
104
105{
106	print FILENAME ":" NR ": unexpected line: " $0 > "/dev/stderr"
107	exitcode = 1
108}
109
110END {
111	exit exitcode
112}
113EOF
114
115cat >boringh.awk <<'EOF'
116/^\/\/ #include/ {sub(/\/\//, ""); print > "goboringcrypto0.h"; next}
117/typedef struct|enum ([a-z_]+ )?{|^[ \t]/ {print >"goboringcrypto1.h";next}
118{gsub(/GO_/, ""); gsub(/enum go_/, "enum "); gsub(/go_point_conv/, "point_conv"); print >"goboringcrypto1.h"}
119EOF
120
121awk -f boringx.awk goboringcrypto.h # writes goboringcrypto.x
122awk -f boringh.awk goboringcrypto.h # writes goboringcrypto[01].h
123
124ls -l ../boringssl/include
125clang++ -std=c++11 -fPIC -I../boringssl/include -O2 -o a.out  goboringcrypto.cc
126./a.out || exit 2
127
128# clang implements u128 % u128 -> u128 by calling __umodti3,
129# which is in libgcc. To make the result self-contained even if linking
130# against a different compiler version, link our own __umodti3 into the syso.
131# This one is specialized so it only expects divisors below 2^64,
132# which is all BoringCrypto uses. (Otherwise it will seg fault.)
133cat >umod-amd64.s <<'EOF'
134# tu_int __umodti3(tu_int x, tu_int y)
135# x is rsi:rdi, y is rcx:rdx, return result is rdx:rax.
136.globl __umodti3
137__umodti3:
138	# specialized to u128 % u64, so verify that
139	test %rcx,%rcx
140	jne 1f
141
142	# save divisor
143	movq %rdx, %r8
144
145	# reduce top 64 bits mod divisor
146	movq %rsi, %rax
147	xorl %edx, %edx
148	divq %r8
149
150	# reduce full 128-bit mod divisor
151	# quotient fits in 64 bits because top 64 bits have been reduced < divisor.
152	# (even though we only care about the remainder, divq also computes
153	# the quotient, and it will trap if the quotient is too large.)
154	movq %rdi, %rax
155	divq %r8
156
157	# expand remainder to 128 for return
158	movq %rdx, %rax
159	xorl %edx, %edx
160	ret
161
1621:
163	# crash - only want 64-bit divisor
164	xorl %ecx, %ecx
165	movl %ecx, 0(%ecx)
166	jmp 1b
167
168.section .note.GNU-stack,"",@progbits
169EOF
170
171cat >umod-arm64.c <<'EOF'
172typedef unsigned int u128 __attribute__((mode(TI)));
173
174static u128 div(u128 x, u128 y, u128 *rp) {
175	int n = 0;
176	while((y>>(128-1)) != 1 && y < x) {
177		y<<=1;
178		n++;
179	}
180	u128 q = 0;
181	for(;; n--, y>>=1, q<<=1) {
182		if(x>=y) {
183			x -= y;
184			q |= 1;
185		}
186		if(n == 0)
187			break;
188	}
189	if(rp)
190		*rp = x;
191	return q;
192}
193
194u128 __umodti3(u128 x, u128 y) {
195	u128 r;
196	div(x, y, &r);
197	return r;
198}
199
200u128 __udivti3(u128 x, u128 y) {
201	return div(x, y, 0);
202}
203EOF
204
205extra=""
206case $GOARCH in
207amd64)
208	cp umod-amd64.s umod.s
209	clang -c -o umod.o umod.s
210	extra=umod.o
211	;;
212arm64)
213	cp umod-arm64.c umod.c
214	clang -c -o umod.o umod.c
215	extra=umod.o
216	;;
217esac
218
219# Prepare copy of libcrypto.a with only the checked functions renamed and exported.
220# All other symbols are left alone and hidden.
221echo BORINGSSL_bcm_power_on_self_test >>syms.txt
222awk '{print "_goboringcrypto_" $0 }' syms.txt >globals.txt
223awk '{print $0 " _goboringcrypto_" $0 }' syms.txt >renames.txt
224objcopy --globalize-symbol=BORINGSSL_bcm_power_on_self_test \
225	../boringssl/build/crypto/libcrypto.a libcrypto.a
226
227# Link together bcm.o and libcrypto.a into a single object.
228ld -r -nostdlib --whole-archive -o goboringcrypto.o libcrypto.a $extra
229
230echo __umodti3 _goboringcrypto___umodti3 >>renames.txt
231echo __udivti3 _goboringcrypto___udivti3 >>renames.txt
232objcopy --remove-section=.llvm_addrsig goboringcrypto.o goboringcrypto1.o # b/179161016
233objcopy --redefine-syms=renames.txt goboringcrypto1.o goboringcrypto2.o
234objcopy --keep-global-symbols=globals.txt --strip-unneeded goboringcrypto2.o goboringcrypto_linux_$GOARCH.syso
235
236# Done!
237ls -l goboringcrypto_linux_$GOARCH.syso
238