1 /*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 // This file is a nearly line-for-line copy of bspatch.c from the
18 // bsdiff-4.3 distribution; the primary differences being how the
19 // input and output data are read and the error handling. Running
20 // applypatch with the -l option will display the bsdiff license
21 // notice.
22
23 #include <stdio.h>
24 #include <sys/stat.h>
25 #include <sys/types.h>
26 #include <errno.h>
27 #include <unistd.h>
28 #include <string.h>
29
30 #include <bzlib.h>
31
32 #include "openssl/sha.h"
33 #include "applypatch.h"
34
ShowBSDiffLicense()35 void ShowBSDiffLicense() {
36 puts("The bsdiff library used herein is:\n"
37 "\n"
38 "Copyright 2003-2005 Colin Percival\n"
39 "All rights reserved\n"
40 "\n"
41 "Redistribution and use in source and binary forms, with or without\n"
42 "modification, are permitted providing that the following conditions\n"
43 "are met:\n"
44 "1. Redistributions of source code must retain the above copyright\n"
45 " notice, this list of conditions and the following disclaimer.\n"
46 "2. Redistributions in binary form must reproduce the above copyright\n"
47 " notice, this list of conditions and the following disclaimer in the\n"
48 " documentation and/or other materials provided with the distribution.\n"
49 "\n"
50 "THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR\n"
51 "IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED\n"
52 "WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE\n"
53 "ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY\n"
54 "DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL\n"
55 "DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS\n"
56 "OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)\n"
57 "HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,\n"
58 "STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING\n"
59 "IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE\n"
60 "POSSIBILITY OF SUCH DAMAGE.\n"
61 "\n------------------\n\n"
62 "This program uses Julian R Seward's \"libbzip2\" library, available\n"
63 "from http://www.bzip.org/.\n"
64 );
65 }
66
offtin(u_char * buf)67 static off_t offtin(u_char *buf)
68 {
69 off_t y;
70
71 y=buf[7]&0x7F;
72 y=y*256;y+=buf[6];
73 y=y*256;y+=buf[5];
74 y=y*256;y+=buf[4];
75 y=y*256;y+=buf[3];
76 y=y*256;y+=buf[2];
77 y=y*256;y+=buf[1];
78 y=y*256;y+=buf[0];
79
80 if(buf[7]&0x80) y=-y;
81
82 return y;
83 }
84
FillBuffer(unsigned char * buffer,int size,bz_stream * stream)85 int FillBuffer(unsigned char* buffer, int size, bz_stream* stream) {
86 stream->next_out = (char*)buffer;
87 stream->avail_out = size;
88 while (stream->avail_out > 0) {
89 int bzerr = BZ2_bzDecompress(stream);
90 if (bzerr != BZ_OK && bzerr != BZ_STREAM_END) {
91 printf("bz error %d decompressing\n", bzerr);
92 return -1;
93 }
94 if (stream->avail_out > 0) {
95 printf("need %d more bytes\n", stream->avail_out);
96 }
97 }
98 return 0;
99 }
100
ApplyBSDiffPatch(const unsigned char * old_data,ssize_t old_size,const Value * patch,ssize_t patch_offset,SinkFn sink,void * token,SHA_CTX * ctx)101 int ApplyBSDiffPatch(const unsigned char* old_data, ssize_t old_size,
102 const Value* patch, ssize_t patch_offset,
103 SinkFn sink, void* token, SHA_CTX* ctx) {
104
105 std::vector<unsigned char> new_data;
106 if (ApplyBSDiffPatchMem(old_data, old_size, patch, patch_offset, &new_data) != 0) {
107 return -1;
108 }
109
110 if (sink(new_data.data(), new_data.size(), token) < static_cast<ssize_t>(new_data.size())) {
111 printf("short write of output: %d (%s)\n", errno, strerror(errno));
112 return 1;
113 }
114 if (ctx) SHA1_Update(ctx, new_data.data(), new_data.size());
115 return 0;
116 }
117
ApplyBSDiffPatchMem(const unsigned char * old_data,ssize_t old_size,const Value * patch,ssize_t patch_offset,std::vector<unsigned char> * new_data)118 int ApplyBSDiffPatchMem(const unsigned char* old_data, ssize_t old_size,
119 const Value* patch, ssize_t patch_offset,
120 std::vector<unsigned char>* new_data) {
121 // Patch data format:
122 // 0 8 "BSDIFF40"
123 // 8 8 X
124 // 16 8 Y
125 // 24 8 sizeof(newfile)
126 // 32 X bzip2(control block)
127 // 32+X Y bzip2(diff block)
128 // 32+X+Y ??? bzip2(extra block)
129 // with control block a set of triples (x,y,z) meaning "add x bytes
130 // from oldfile to x bytes from the diff block; copy y bytes from the
131 // extra block; seek forwards in oldfile by z bytes".
132
133 unsigned char* header = (unsigned char*) patch->data + patch_offset;
134 if (memcmp(header, "BSDIFF40", 8) != 0) {
135 printf("corrupt bsdiff patch file header (magic number)\n");
136 return 1;
137 }
138
139 ssize_t ctrl_len, data_len, new_size;
140 ctrl_len = offtin(header+8);
141 data_len = offtin(header+16);
142 new_size = offtin(header+24);
143
144 if (ctrl_len < 0 || data_len < 0 || new_size < 0) {
145 printf("corrupt patch file header (data lengths)\n");
146 return 1;
147 }
148
149 int bzerr;
150
151 bz_stream cstream;
152 cstream.next_in = patch->data + patch_offset + 32;
153 cstream.avail_in = ctrl_len;
154 cstream.bzalloc = NULL;
155 cstream.bzfree = NULL;
156 cstream.opaque = NULL;
157 if ((bzerr = BZ2_bzDecompressInit(&cstream, 0, 0)) != BZ_OK) {
158 printf("failed to bzinit control stream (%d)\n", bzerr);
159 }
160
161 bz_stream dstream;
162 dstream.next_in = patch->data + patch_offset + 32 + ctrl_len;
163 dstream.avail_in = data_len;
164 dstream.bzalloc = NULL;
165 dstream.bzfree = NULL;
166 dstream.opaque = NULL;
167 if ((bzerr = BZ2_bzDecompressInit(&dstream, 0, 0)) != BZ_OK) {
168 printf("failed to bzinit diff stream (%d)\n", bzerr);
169 }
170
171 bz_stream estream;
172 estream.next_in = patch->data + patch_offset + 32 + ctrl_len + data_len;
173 estream.avail_in = patch->size - (patch_offset + 32 + ctrl_len + data_len);
174 estream.bzalloc = NULL;
175 estream.bzfree = NULL;
176 estream.opaque = NULL;
177 if ((bzerr = BZ2_bzDecompressInit(&estream, 0, 0)) != BZ_OK) {
178 printf("failed to bzinit extra stream (%d)\n", bzerr);
179 }
180
181 new_data->resize(new_size);
182
183 off_t oldpos = 0, newpos = 0;
184 off_t ctrl[3];
185 off_t len_read;
186 int i;
187 unsigned char buf[24];
188 while (newpos < new_size) {
189 // Read control data
190 if (FillBuffer(buf, 24, &cstream) != 0) {
191 printf("error while reading control stream\n");
192 return 1;
193 }
194 ctrl[0] = offtin(buf);
195 ctrl[1] = offtin(buf+8);
196 ctrl[2] = offtin(buf+16);
197
198 if (ctrl[0] < 0 || ctrl[1] < 0) {
199 printf("corrupt patch (negative byte counts)\n");
200 return 1;
201 }
202
203 // Sanity check
204 if (newpos + ctrl[0] > new_size) {
205 printf("corrupt patch (new file overrun)\n");
206 return 1;
207 }
208
209 // Read diff string
210 if (FillBuffer(new_data->data() + newpos, ctrl[0], &dstream) != 0) {
211 printf("error while reading diff stream\n");
212 return 1;
213 }
214
215 // Add old data to diff string
216 for (i = 0; i < ctrl[0]; ++i) {
217 if ((oldpos+i >= 0) && (oldpos+i < old_size)) {
218 (*new_data)[newpos+i] += old_data[oldpos+i];
219 }
220 }
221
222 // Adjust pointers
223 newpos += ctrl[0];
224 oldpos += ctrl[0];
225
226 // Sanity check
227 if (newpos + ctrl[1] > new_size) {
228 printf("corrupt patch (new file overrun)\n");
229 return 1;
230 }
231
232 // Read extra string
233 if (FillBuffer(new_data->data() + newpos, ctrl[1], &estream) != 0) {
234 printf("error while reading extra stream\n");
235 return 1;
236 }
237
238 // Adjust pointers
239 newpos += ctrl[1];
240 oldpos += ctrl[2];
241 }
242
243 BZ2_bzDecompressEnd(&cstream);
244 BZ2_bzDecompressEnd(&dstream);
245 BZ2_bzDecompressEnd(&estream);
246 return 0;
247 }
248