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