| // Copyright (c) 2006, Google Inc. |
| // All rights reserved. |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following disclaimer |
| // in the documentation and/or other materials provided with the |
| // distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived from |
| // this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| // macho_walker.cc: Iterate over the load commands in a mach-o file |
| // |
| // See macho_walker.h for documentation |
| // |
| // Author: Dan Waylonis |
| |
| #include <assert.h> |
| #include <fcntl.h> |
| #include <mach-o/arch.h> |
| #include <mach-o/fat.h> |
| #include <mach-o/loader.h> |
| #include <string.h> |
| #include <unistd.h> |
| |
| #include "common/mac/byteswap.h" |
| #include "common/mac/macho_walker.h" |
| #include "common/mac/macho_utilities.h" |
| |
| namespace MacFileUtilities { |
| |
| MachoWalker::MachoWalker(const char *path, LoadCommandCallback callback, |
| void *context) |
| : file_(-1), |
| memory_(NULL), |
| memory_size_(0), |
| callback_(callback), |
| callback_context_(context), |
| current_header_(NULL), |
| current_header_size_(0), |
| current_header_offset_(0) { |
| file_ = open(path, O_RDONLY); |
| } |
| |
| MachoWalker::MachoWalker(void *memory, size_t size, |
| LoadCommandCallback callback, void *context) |
| : file_(-1), |
| memory_(memory), |
| memory_size_(size), |
| callback_(callback), |
| callback_context_(context), |
| current_header_(NULL), |
| current_header_size_(0), |
| current_header_offset_(0) { |
| } |
| |
| MachoWalker::~MachoWalker() { |
| if (file_ != -1) |
| close(file_); |
| } |
| |
| bool MachoWalker::WalkHeader(cpu_type_t cpu_type, cpu_subtype_t cpu_subtype) { |
| cpu_type_t valid_cpu_type = cpu_type; |
| cpu_subtype_t valid_cpu_subtype = cpu_subtype; |
| // if |cpu_type| is 0, use the native cpu type. |
| if (cpu_type == 0) { |
| const NXArchInfo *arch = NXGetLocalArchInfo(); |
| assert(arch); |
| valid_cpu_type = arch->cputype; |
| valid_cpu_subtype = CPU_SUBTYPE_MULTIPLE; |
| } |
| off_t offset; |
| if (FindHeader(valid_cpu_type, valid_cpu_subtype, offset)) { |
| if (cpu_type & CPU_ARCH_ABI64) |
| return WalkHeader64AtOffset(offset); |
| |
| return WalkHeaderAtOffset(offset); |
| } |
| |
| return false; |
| } |
| |
| bool MachoWalker::ReadBytes(void *buffer, size_t size, off_t offset) { |
| if (memory_) { |
| if (offset < 0) |
| return false; |
| bool result = true; |
| if (offset + size > memory_size_) { |
| if (static_cast<size_t>(offset) >= memory_size_) |
| return false; |
| size = memory_size_ - static_cast<size_t>(offset); |
| result = false; |
| } |
| memcpy(buffer, static_cast<char *>(memory_) + offset, size); |
| return result; |
| } else { |
| return pread(file_, buffer, size, offset) == (ssize_t)size; |
| } |
| } |
| |
| bool MachoWalker::CurrentHeader(struct mach_header_64 *header, off_t *offset) { |
| if (current_header_) { |
| memcpy(header, current_header_, sizeof(mach_header_64)); |
| *offset = current_header_offset_; |
| return true; |
| } |
| |
| return false; |
| } |
| |
| bool MachoWalker::FindHeader(cpu_type_t cpu_type, |
| cpu_subtype_t cpu_subtype, |
| off_t &offset) { |
| // Read the magic bytes that's common amongst all mach-o files |
| uint32_t magic; |
| if (!ReadBytes(&magic, sizeof(magic), 0)) |
| return false; |
| |
| offset = sizeof(magic); |
| |
| // Figure out what type of file we've got |
| bool is_fat = false; |
| if (magic == FAT_MAGIC || magic == FAT_CIGAM) { |
| is_fat = true; |
| } |
| else if (magic != MH_MAGIC && magic != MH_CIGAM && magic != MH_MAGIC_64 && |
| magic != MH_CIGAM_64) { |
| return false; |
| } |
| |
| if (!is_fat) { |
| // If we don't have a fat header, check if the cpu type matches the single |
| // header |
| struct mach_header header; |
| if (!ReadBytes(&header, sizeof(header), 0)) |
| return false; |
| |
| if (magic == MH_CIGAM || magic == MH_CIGAM_64) |
| breakpad_swap_mach_header(&header); |
| |
| if (cpu_type != header.cputype || |
| (cpu_subtype != CPU_SUBTYPE_MULTIPLE && |
| cpu_subtype != header.cpusubtype)) { |
| return false; |
| } |
| |
| offset = 0; |
| return true; |
| } else { |
| // Read the fat header and find an appropriate architecture |
| offset = 0; |
| struct fat_header fat; |
| if (!ReadBytes(&fat, sizeof(fat), offset)) |
| return false; |
| |
| if (NXHostByteOrder() != NX_BigEndian) |
| breakpad_swap_fat_header(&fat); |
| |
| offset += sizeof(fat); |
| |
| // Search each architecture for the desired one |
| struct fat_arch arch; |
| for (uint32_t i = 0; i < fat.nfat_arch; ++i) { |
| if (!ReadBytes(&arch, sizeof(arch), offset)) |
| return false; |
| |
| if (NXHostByteOrder() != NX_BigEndian) |
| breakpad_swap_fat_arch(&arch, 1); |
| |
| if (arch.cputype == cpu_type && |
| (cpu_subtype == CPU_SUBTYPE_MULTIPLE || |
| arch.cpusubtype == cpu_subtype)) { |
| offset = arch.offset; |
| return true; |
| } |
| |
| offset += sizeof(arch); |
| } |
| } |
| |
| return false; |
| } |
| |
| bool MachoWalker::WalkHeaderAtOffset(off_t offset) { |
| struct mach_header header; |
| if (!ReadBytes(&header, sizeof(header), offset)) |
| return false; |
| |
| bool swap = (header.magic == MH_CIGAM); |
| if (swap) |
| breakpad_swap_mach_header(&header); |
| |
| // Copy the data into the mach_header_64 structure. Since the 32-bit and |
| // 64-bit only differ in the last field (reserved), this is safe to do. |
| struct mach_header_64 header64; |
| memcpy((void *)&header64, (const void *)&header, sizeof(header)); |
| header64.reserved = 0; |
| |
| current_header_ = &header64; |
| current_header_size_ = sizeof(header); // 32-bit, not 64-bit |
| current_header_offset_ = offset; |
| offset += current_header_size_; |
| bool result = WalkHeaderCore(offset, header.ncmds, swap); |
| current_header_ = NULL; |
| current_header_size_ = 0; |
| current_header_offset_ = 0; |
| return result; |
| } |
| |
| bool MachoWalker::WalkHeader64AtOffset(off_t offset) { |
| struct mach_header_64 header; |
| if (!ReadBytes(&header, sizeof(header), offset)) |
| return false; |
| |
| bool swap = (header.magic == MH_CIGAM_64); |
| if (swap) |
| breakpad_swap_mach_header_64(&header); |
| |
| current_header_ = &header; |
| current_header_size_ = sizeof(header); |
| current_header_offset_ = offset; |
| offset += current_header_size_; |
| bool result = WalkHeaderCore(offset, header.ncmds, swap); |
| current_header_ = NULL; |
| current_header_size_ = 0; |
| current_header_offset_ = 0; |
| return result; |
| } |
| |
| bool MachoWalker::WalkHeaderCore(off_t offset, uint32_t number_of_commands, |
| bool swap) { |
| for (uint32_t i = 0; i < number_of_commands; ++i) { |
| struct load_command cmd; |
| if (!ReadBytes(&cmd, sizeof(cmd), offset)) |
| return false; |
| |
| if (swap) |
| breakpad_swap_load_command(&cmd); |
| |
| // Call the user callback |
| if (callback_ && !callback_(this, &cmd, offset, swap, callback_context_)) |
| break; |
| |
| offset += cmd.cmdsize; |
| } |
| |
| return true; |
| } |
| |
| } // namespace MacFileUtilities |