1 /* 2 * Copyright (C) 2009 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 // See imgdiff.c in this directory for a description of the patch file 18 // format. 19 20 #include <stdio.h> 21 #include <sys/stat.h> 22 #include <errno.h> 23 #include <unistd.h> 24 #include <string.h> 25 26 #include "zlib.h" 27 #include "mincrypt/sha.h" 28 #include "applypatch.h" 29 #include "imgdiff.h" 30 #include "utils.h" 31 32 /* 33 * Apply the patch given in 'patch_filename' to the source data given 34 * by (old_data, old_size). Write the patched output to the 'output' 35 * file, and update the SHA context with the output data as well. 36 * Return 0 on success. 37 */ 38 int ApplyImagePatch(const unsigned char* old_data, ssize_t old_size, 39 const Value* patch, 40 SinkFn sink, void* token, SHA_CTX* ctx) { 41 ssize_t pos = 12; 42 char* header = patch->data; 43 if (patch->size < 12) { 44 printf("patch too short to contain header\n"); 45 return -1; 46 } 47 48 // IMGDIFF2 uses CHUNK_NORMAL, CHUNK_DEFLATE, and CHUNK_RAW. 49 // (IMGDIFF1, which is no longer supported, used CHUNK_NORMAL and 50 // CHUNK_GZIP.) 51 if (memcmp(header, "IMGDIFF2", 8) != 0) { 52 printf("corrupt patch file header (magic number)\n"); 53 return -1; 54 } 55 56 int num_chunks = Read4(header+8); 57 58 int i; 59 for (i = 0; i < num_chunks; ++i) { 60 // each chunk's header record starts with 4 bytes. 61 if (pos + 4 > patch->size) { 62 printf("failed to read chunk %d record\n", i); 63 return -1; 64 } 65 int type = Read4(patch->data + pos); 66 pos += 4; 67 68 if (type == CHUNK_NORMAL) { 69 char* normal_header = patch->data + pos; 70 pos += 24; 71 if (pos > patch->size) { 72 printf("failed to read chunk %d normal header data\n", i); 73 return -1; 74 } 75 76 size_t src_start = Read8(normal_header); 77 size_t src_len = Read8(normal_header+8); 78 size_t patch_offset = Read8(normal_header+16); 79 80 ApplyBSDiffPatch(old_data + src_start, src_len, 81 patch, patch_offset, sink, token, ctx); 82 } else if (type == CHUNK_RAW) { 83 char* raw_header = patch->data + pos; 84 pos += 4; 85 if (pos > patch->size) { 86 printf("failed to read chunk %d raw header data\n", i); 87 return -1; 88 } 89 90 ssize_t data_len = Read4(raw_header); 91 92 if (pos + data_len > patch->size) { 93 printf("failed to read chunk %d raw data\n", i); 94 return -1; 95 } 96 SHA_update(ctx, patch->data + pos, data_len); 97 if (sink((unsigned char*)patch->data + pos, 98 data_len, token) != data_len) { 99 printf("failed to write chunk %d raw data\n", i); 100 return -1; 101 } 102 pos += data_len; 103 } else if (type == CHUNK_DEFLATE) { 104 // deflate chunks have an additional 60 bytes in their chunk header. 105 char* deflate_header = patch->data + pos; 106 pos += 60; 107 if (pos > patch->size) { 108 printf("failed to read chunk %d deflate header data\n", i); 109 return -1; 110 } 111 112 size_t src_start = Read8(deflate_header); 113 size_t src_len = Read8(deflate_header+8); 114 size_t patch_offset = Read8(deflate_header+16); 115 size_t expanded_len = Read8(deflate_header+24); 116 size_t target_len = Read8(deflate_header+32); 117 int level = Read4(deflate_header+40); 118 int method = Read4(deflate_header+44); 119 int windowBits = Read4(deflate_header+48); 120 int memLevel = Read4(deflate_header+52); 121 int strategy = Read4(deflate_header+56); 122 123 // Decompress the source data; the chunk header tells us exactly 124 // how big we expect it to be when decompressed. 125 126 unsigned char* expanded_source = malloc(expanded_len); 127 if (expanded_source == NULL) { 128 printf("failed to allocate %d bytes for expanded_source\n", 129 expanded_len); 130 return -1; 131 } 132 133 z_stream strm; 134 strm.zalloc = Z_NULL; 135 strm.zfree = Z_NULL; 136 strm.opaque = Z_NULL; 137 strm.avail_in = src_len; 138 strm.next_in = (unsigned char*)(old_data + src_start); 139 strm.avail_out = expanded_len; 140 strm.next_out = expanded_source; 141 142 int ret; 143 ret = inflateInit2(&strm, -15); 144 if (ret != Z_OK) { 145 printf("failed to init source inflation: %d\n", ret); 146 return -1; 147 } 148 149 // Because we've provided enough room to accommodate the output 150 // data, we expect one call to inflate() to suffice. 151 ret = inflate(&strm, Z_SYNC_FLUSH); 152 if (ret != Z_STREAM_END) { 153 printf("source inflation returned %d\n", ret); 154 return -1; 155 } 156 // We should have filled the output buffer exactly. 157 if (strm.avail_out != 0) { 158 printf("source inflation short by %d bytes\n", strm.avail_out); 159 return -1; 160 } 161 inflateEnd(&strm); 162 163 // Next, apply the bsdiff patch (in memory) to the uncompressed 164 // data. 165 unsigned char* uncompressed_target_data; 166 ssize_t uncompressed_target_size; 167 if (ApplyBSDiffPatchMem(expanded_source, expanded_len, 168 patch, patch_offset, 169 &uncompressed_target_data, 170 &uncompressed_target_size) != 0) { 171 return -1; 172 } 173 174 // Now compress the target data and append it to the output. 175 176 // we're done with the expanded_source data buffer, so we'll 177 // reuse that memory to receive the output of deflate. 178 unsigned char* temp_data = expanded_source; 179 ssize_t temp_size = expanded_len; 180 if (temp_size < 32768) { 181 // ... unless the buffer is too small, in which case we'll 182 // allocate a fresh one. 183 free(temp_data); 184 temp_data = malloc(32768); 185 temp_size = 32768; 186 } 187 188 // now the deflate stream 189 strm.zalloc = Z_NULL; 190 strm.zfree = Z_NULL; 191 strm.opaque = Z_NULL; 192 strm.avail_in = uncompressed_target_size; 193 strm.next_in = uncompressed_target_data; 194 ret = deflateInit2(&strm, level, method, windowBits, memLevel, strategy); 195 do { 196 strm.avail_out = temp_size; 197 strm.next_out = temp_data; 198 ret = deflate(&strm, Z_FINISH); 199 ssize_t have = temp_size - strm.avail_out; 200 201 if (sink(temp_data, have, token) != have) { 202 printf("failed to write %ld compressed bytes to output\n", 203 (long)have); 204 return -1; 205 } 206 SHA_update(ctx, temp_data, have); 207 } while (ret != Z_STREAM_END); 208 deflateEnd(&strm); 209 210 free(temp_data); 211 free(uncompressed_target_data); 212 } else { 213 printf("patch chunk %d is unknown type %d\n", i, type); 214 return -1; 215 } 216 } 217 218 return 0; 219 } 220
