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| 1 // Copyright (c) 2006, Google Inc. | |
| 2 // All rights reserved. | |
| 3 // | |
| 4 // Redistribution and use in source and binary forms, with or without | |
| 5 // modification, are permitted provided that the following conditions are | |
| 6 // met: | |
| 7 // | |
| 8 // * Redistributions of source code must retain the above copyright | |
| 9 // notice, this list of conditions and the following disclaimer. | |
| 10 // * Redistributions in binary form must reproduce the above | |
| 11 // copyright notice, this list of conditions and the following disclaimer | |
| 12 // in the documentation and/or other materials provided with the | |
| 13 // distribution. | |
| 14 // * Neither the name of Google Inc. nor the names of its | |
| 15 // contributors may be used to endorse or promote products derived from | |
| 16 // this software without specific prior written permission. | |
| 17 // | |
| 18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
| 19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
| 20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | |
| 21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | |
| 22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
| 23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | |
| 24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
| 25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
| 26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
| 27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
| 28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 29 | |
| 30 // macho_walker.cc: Iterate over the load commands in a mach-o file | |
| 31 // | |
| 32 // See macho_walker.h for documentation | |
| 33 // | |
| 34 // Author: Dan Waylonis | |
| 35 | |
| 36 extern "C" { // necessary for Leopard | |
| 37 #include <assert.h> | |
| 38 #include <fcntl.h> | |
| 39 #include <mach-o/arch.h> | |
| 40 #include <mach-o/loader.h> | |
| 41 #include <mach-o/swap.h> | |
| 42 #include <string.h> | |
| 43 #include <unistd.h> | |
| 44 } | |
| 45 | |
| 46 #include "common/mac/macho_walker.h" | |
| 47 #include "common/mac/macho_utilities.h" | |
| 48 | |
| 49 namespace MacFileUtilities { | |
| 50 | |
| 51 MachoWalker::MachoWalker(const char *path, LoadCommandCallback callback, | |
| 52 void *context) | |
| 53 : callback_(callback), | |
| 54 callback_context_(context) { | |
| 55 file_ = open(path, O_RDONLY); | |
| 56 } | |
| 57 | |
| 58 MachoWalker::~MachoWalker() { | |
| 59 if (file_ != -1) | |
| 60 close(file_); | |
| 61 } | |
| 62 | |
| 63 int MachoWalker::ValidateCPUType(int cpu_type) { | |
| 64 // If the user didn't specify, try to use the local architecture. If that | |
| 65 // fails, use the base type for the executable. | |
| 66 if (cpu_type == 0) { | |
| 67 const NXArchInfo *arch = NXGetLocalArchInfo(); | |
| 68 if (arch) | |
| 69 cpu_type = arch->cputype; | |
| 70 else | |
| 71 #if __ppc__ | |
| 72 cpu_type = CPU_TYPE_POWERPC; | |
| 73 #elif __i386__ | |
| 74 cpu_type = CPU_TYPE_X86; | |
| 75 #else | |
| 76 #error Unknown architecture -- are you on a PDP-11? | |
| 77 #endif | |
| 78 } | |
| 79 | |
| 80 return cpu_type; | |
| 81 } | |
| 82 | |
| 83 bool MachoWalker::WalkHeader(int cpu_type) { | |
| 84 int valid_cpu_type = ValidateCPUType(cpu_type); | |
| 85 off_t offset; | |
| 86 if (FindHeader(valid_cpu_type, offset)) { | |
| 87 if (cpu_type & CPU_ARCH_ABI64) | |
| 88 return WalkHeader64AtOffset(offset); | |
| 89 | |
| 90 return WalkHeaderAtOffset(offset); | |
| 91 } | |
| 92 | |
| 93 return false; | |
| 94 } | |
| 95 | |
| 96 bool MachoWalker::ReadBytes(void *buffer, size_t size, off_t offset) { | |
| 97 return pread(file_, buffer, size, offset) == (ssize_t)size; | |
| 98 } | |
| 99 | |
| 100 bool MachoWalker::CurrentHeader(struct mach_header_64 *header, off_t *offset) { | |
| 101 if (current_header_) { | |
| 102 memcpy(header, current_header_, sizeof(mach_header_64)); | |
| 103 *offset = current_header_offset_; | |
| 104 return true; | |
| 105 } | |
| 106 | |
| 107 return false; | |
| 108 } | |
| 109 | |
| 110 bool MachoWalker::FindHeader(int cpu_type, off_t &offset) { | |
| 111 int valid_cpu_type = ValidateCPUType(cpu_type); | |
| 112 // Read the magic bytes that's common amongst all mach-o files | |
| 113 uint32_t magic; | |
| 114 if (!ReadBytes(&magic, sizeof(magic), 0)) | |
| 115 return false; | |
| 116 | |
| 117 offset = sizeof(magic); | |
| 118 | |
| 119 // Figure out what type of file we've got | |
| 120 bool is_fat = false; | |
| 121 if (magic == FAT_MAGIC || magic == FAT_CIGAM) { | |
| 122 is_fat = true; | |
| 123 } | |
| 124 else if (magic != MH_MAGIC && magic != MH_CIGAM && magic != MH_MAGIC_64 && | |
| 125 magic != MH_CIGAM_64) { | |
| 126 return false; | |
| 127 } | |
| 128 | |
| 129 if (!is_fat) { | |
| 130 // If we don't have a fat header, check if the cpu type matches the single | |
| 131 // header | |
| 132 cpu_type_t header_cpu_type; | |
| 133 if (!ReadBytes(&header_cpu_type, sizeof(header_cpu_type), offset)) | |
| 134 return false; | |
| 135 | |
| 136 if (magic == MH_CIGAM || magic == MH_CIGAM_64) | |
| 137 header_cpu_type = NXSwapInt(header_cpu_type); | |
| 138 | |
| 139 if (valid_cpu_type != header_cpu_type) | |
| 140 return false; | |
| 141 | |
| 142 offset = 0; | |
| 143 return true; | |
| 144 } else { | |
| 145 // Read the fat header and find an appropriate architecture | |
| 146 offset = 0; | |
| 147 struct fat_header fat; | |
| 148 if (!ReadBytes(&fat, sizeof(fat), offset)) | |
| 149 return false; | |
| 150 | |
| 151 if (NXHostByteOrder() != NX_BigEndian) | |
| 152 swap_fat_header(&fat, NXHostByteOrder()); | |
| 153 | |
| 154 offset += sizeof(fat); | |
| 155 | |
| 156 // Search each architecture for the desired one | |
| 157 struct fat_arch arch; | |
| 158 for (uint32_t i = 0; i < fat.nfat_arch; ++i) { | |
| 159 if (!ReadBytes(&arch, sizeof(arch), offset)) | |
| 160 return false; | |
| 161 | |
| 162 if (NXHostByteOrder() != NX_BigEndian) | |
| 163 swap_fat_arch(&arch, 1, NXHostByteOrder()); | |
| 164 | |
| 165 if (arch.cputype == valid_cpu_type) { | |
| 166 offset = arch.offset; | |
| 167 return true; | |
| 168 } | |
| 169 | |
| 170 offset += sizeof(arch); | |
| 171 } | |
| 172 } | |
| 173 | |
| 174 return false; | |
| 175 } | |
| 176 | |
| 177 bool MachoWalker::WalkHeaderAtOffset(off_t offset) { | |
| 178 struct mach_header header; | |
| 179 if (!ReadBytes(&header, sizeof(header), offset)) | |
| 180 return false; | |
| 181 | |
| 182 bool swap = (header.magic == MH_CIGAM); | |
| 183 if (swap) | |
| 184 swap_mach_header(&header, NXHostByteOrder()); | |
| 185 | |
| 186 // Copy the data into the mach_header_64 structure. Since the 32-bit and | |
| 187 // 64-bit only differ in the last field (reserved), this is safe to do. | |
| 188 struct mach_header_64 header64; | |
| 189 memcpy((void *)&header64, (const void *)&header, sizeof(header)); | |
| 190 header64.reserved = 0; | |
| 191 | |
| 192 current_header_ = &header64; | |
| 193 current_header_size_ = sizeof(header); // 32-bit, not 64-bit | |
| 194 current_header_offset_ = offset; | |
| 195 offset += current_header_size_; | |
| 196 bool result = WalkHeaderCore(offset, header.ncmds, swap); | |
| 197 current_header_ = NULL; | |
| 198 current_header_size_ = 0; | |
| 199 current_header_offset_ = 0; | |
| 200 return result; | |
| 201 } | |
| 202 | |
| 203 bool MachoWalker::WalkHeader64AtOffset(off_t offset) { | |
| 204 struct mach_header_64 header; | |
| 205 if (!ReadBytes(&header, sizeof(header), offset)) | |
| 206 return false; | |
| 207 | |
| 208 bool swap = (header.magic == MH_CIGAM_64); | |
| 209 if (swap) | |
| 210 breakpad_swap_mach_header_64(&header, NXHostByteOrder()); | |
| 211 | |
| 212 current_header_ = &header; | |
| 213 current_header_size_ = sizeof(header); | |
| 214 current_header_offset_ = offset; | |
| 215 offset += current_header_size_; | |
| 216 bool result = WalkHeaderCore(offset, header.ncmds, swap); | |
| 217 current_header_ = NULL; | |
| 218 current_header_size_ = 0; | |
| 219 current_header_offset_ = 0; | |
| 220 return result; | |
| 221 } | |
| 222 | |
| 223 bool MachoWalker::WalkHeaderCore(off_t offset, uint32_t number_of_commands, | |
| 224 bool swap) { | |
| 225 for (uint32_t i = 0; i < number_of_commands; ++i) { | |
| 226 struct load_command cmd; | |
| 227 if (!ReadBytes(&cmd, sizeof(cmd), offset)) | |
| 228 return false; | |
| 229 | |
| 230 if (swap) | |
| 231 swap_load_command(&cmd, NXHostByteOrder()); | |
| 232 | |
| 233 // Call the user callback | |
| 234 if (callback_ && !callback_(this, &cmd, offset, swap, callback_context_)) | |
| 235 break; | |
| 236 | |
| 237 offset += cmd.cmdsize; | |
| 238 } | |
| 239 | |
| 240 return true; | |
| 241 } | |
| 242 | |
| 243 } // namespace MacFileUtilities | |
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Chromium Code Reviews
Issue 10928195:
First round of dead file removal (Closed)
Base URL: https://github.com/samclegg/nativeclient-sdk.git@master