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Add classes to: walk mach-o files, look for identifiers, and return a 16 byte unique identifier. Fixes #106.

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git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@102 4c0a9323-5329-0410-9bdc-e9ce6186880e
This commit is contained in:
waylonis 2007-01-11 01:49:07 +00:00
parent 97d392dc4b
commit fd98b2af37
6 changed files with 919 additions and 0 deletions
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104
src/common/mac/file_id.cc Normal file
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// 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
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// file_id.cc: Return a unique identifier for a file
//
// See file_id.h for documentation
//
// Author: Dan Waylonis
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
#include "common/mac/file_id.h"
#include "common/mac/macho_id.h"
using MacFileUtilities::MachoID;
namespace google_airbag {
FileID::FileID(const char *path) {
strlcpy(path_, path, sizeof(path_));
}
bool FileID::FileIdentifier(unsigned char identifier[16]) {
int fd = open(path_, O_RDONLY);
if (fd == -1)
return false;
MD5_CTX md5;
MD5_Init(&md5);
// Read 4k x 2 bytes at a time. This is faster than just 4k bytes, but
// doesn't seem to be an unreasonable size for the stack.
unsigned char buffer[4096 * 2];
size_t buffer_size = sizeof(buffer);
while ((buffer_size = read(fd, buffer, buffer_size) > 0)) {
MD5_Update(&md5, buffer, buffer_size);
}
close(fd);
MD5_Final(identifier, &md5);
return true;
}
bool FileID::MachoIdentifier(int cpu_type, unsigned char identifier[16]) {
MachoID macho(path_);
if (macho.UUIDCommand(cpu_type, identifier))
return true;
if (macho.IDCommand(cpu_type, identifier))
return true;
return macho.MD5(cpu_type, identifier);
}
// static
void FileID::ConvertIdentifierToString(const unsigned char identifier[16],
char *buffer, int buffer_length) {
int buffer_idx = 0;
for (int idx = 0; (buffer_idx < buffer_length) && (idx < 16); ++idx) {
int hi = (identifier[idx] >> 4) & 0x0F;
int lo = (identifier[idx]) & 0x0F;
if (idx == 4 || idx == 6 || idx == 8 || idx == 10)
buffer[buffer_idx++] = '-';
buffer[buffer_idx++] = (hi >= 10) ? 'A' + hi - 10 : '0' + hi;
buffer[buffer_idx++] = (lo >= 10) ? 'A' + lo - 10 : '0' + lo;
}
// NULL terminate
buffer[(buffer_idx < buffer_length) ? buffer_idx : buffer_idx - 1] = 0;
}
} // namespace google_airbag

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// 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
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// file_id.h: Return a unique identifier for a file
//
// Author: Dan Waylonis
#ifndef COMMON_MAC_FILE_ID_H__
#define COMMON_MAC_FILE_ID_H__
#include <limits.h>
namespace google_airbag {
class FileID {
public:
FileID(const char *path);
~FileID() {};
// Load the identifier for the file path specified in the constructor into
// |identifier|. Return false if the identifier could not be created for the
// file.
// The current implementation will return the MD5 hash of the file's bytes.
bool FileIdentifier(unsigned char identifier[16]);
// Treat the file as a mach-o file that will contain one or more archicture.
// Accepted values for |cpu_type| (e.g., CPU_TYPE_X86 or CPU_TYPE_POWERPC)
// are listed in /usr/include/mach/machine.h.
// If |cpu_type| is 0, then the native cpu type is used.
// Returns false if opening the file failed or if the |cpu_type| is not
// present in the file.
// Return the unique identifier in |identifier|.
// The current implementation will look for the (in order of priority):
// LC_UUID, LC_ID_DYLIB, or MD5 hash of the given |cpu_type|.
bool MachoIdentifier(int cpu_type, unsigned char identifier[16]);
// Convert the |identifier| data to a NULL terminated string. The string will
// be formatted as a UUID (e.g., 22F065BB-FC9C-49F7-80FE-26A7CEBD7BCE).
// The |buffer| should be at least 37 bytes long to receive all of the data
// and termination. Shorter buffers will contain truncated data.
static void ConvertIdentifierToString(const unsigned char identifier[16],
char *buffer, int buffer_length);
private:
// Storage for the path specified
char path_[PATH_MAX];
};
} // namespace google_airbag
#endif // COMMON_MAC_FILE_ID_H__

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// 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
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (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_id.cc: Functions to gather identifying information from a macho file
//
// See macho_id.h for documentation
//
// Author: Dan Waylonis
#include <fcntl.h>
#include <mach-o/loader.h>
#include <mach-o/swap.h>
#include <openssl/md5.h>
#include <openssl/sha.h>
#include <stdio.h>
#include <string.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#include "common/mac/macho_id.h"
#include "common/mac/macho_walker.h"
namespace MacFileUtilities {
MachoID::MachoID(const char *path) {
strlcpy(path_, path, sizeof(path_));
file_ = open(path, O_RDONLY);
}
MachoID::~MachoID() {
if (file_ != -1)
close(file_);
}
// The CRC info is from http://en.wikipedia.org/wiki/Adler-32
// With optimizations from http://www.zlib.net/
// The largest prime smaller than 65536
#define MOD_ADLER 65521
// MAX_BLOCK is the largest n such that 255n(n+1)/2 + (n+1)(MAX_BLOCK-1) <= 2^32-1
#define MAX_BLOCK 5552
void MachoID::UpdateCRC(unsigned char *bytes, size_t size) {
// Unrolled loops for summing
#define DO1(buf,i) {sum1 += (buf)[i]; sum2 += sum1;}
#define DO2(buf,i) DO1(buf,i); DO1(buf,i+1);
#define DO4(buf,i) DO2(buf,i); DO2(buf,i+2);
#define DO8(buf,i) DO4(buf,i); DO4(buf,i+4);
#define DO16(buf) DO8(buf,0); DO8(buf,8);
// Split up the crc
uint32_t sum1 = crc_ & 0xFFFF;
uint32_t sum2 = (crc_ >> 16) & 0xFFFF;
// Do large blocks
while (size >= MAX_BLOCK) {
size -= MAX_BLOCK;
int block_count = MAX_BLOCK / 16;
do {
DO16(bytes);
bytes += 16;
} while (--block_count);
sum1 %= MOD_ADLER;
sum2 %= MOD_ADLER;
}
// Do remaining bytes
if (size) {
while (size >= 16) {
size -= 16;
DO16(bytes);
bytes += 16;
}
while (size--) {
sum1 += *bytes++;
sum2 += sum1;
}
sum1 %= MOD_ADLER;
sum2 %= MOD_ADLER;
crc_ = (sum2 << 16) | sum1;
}
}
void MachoID::UpdateMD5(unsigned char *bytes, size_t size) {
MD5_Update(&md5_context_, bytes, size);
}
void MachoID::UpdateSHA1(unsigned char *bytes, size_t size) {
SHA_Update(&sha1_context_, bytes, size);
}
void MachoID::Update(unsigned char *bytes, size_t size) {
if (update_function_)
(this->*update_function_)(bytes, size);
}
bool MachoID::UUIDCommand(int cpu_type, unsigned char bytes[16]) {
struct uuid_command uuid_cmd;
MachoWalker walker(path_, UUIDWalkerCB, &uuid_cmd);
uuid_cmd.cmd = 0;
if (!walker.WalkHeader(cpu_type))
return false;
// If we found the command, we'll have initialized the uuid_command
// structure
if (uuid_cmd.cmd == LC_UUID) {
memcpy(bytes, uuid_cmd.uuid, sizeof(uuid_cmd.uuid));
return true;
}
return false;
}
bool MachoID::IDCommand(int cpu_type, unsigned char identifier[16]) {
struct dylib_command dylib_cmd;
MachoWalker walker(path_, IDWalkerCB, &dylib_cmd);
dylib_cmd.cmd = 0;
if (!walker.WalkHeader(cpu_type))
return false;
// If we found the command, we'll have initialized the dylib_command
// structure
if (dylib_cmd.cmd == LC_ID_DYLIB) {
// Take the timestamp, version, and compatability version bytes to form
// the first 12 bytes, pad the rest with zeros
identifier[0] = (dylib_cmd.dylib.timestamp >> 24) & 0xFF;
identifier[1] = (dylib_cmd.dylib.timestamp >> 16) & 0xFF;
identifier[2] = (dylib_cmd.dylib.timestamp >> 8) & 0xFF;
identifier[3] = dylib_cmd.dylib.timestamp & 0xFF;
identifier[4] = (dylib_cmd.dylib.current_version >> 24) & 0xFF;
identifier[5] = (dylib_cmd.dylib.current_version >> 16) & 0xFF;
identifier[6] = (dylib_cmd.dylib.current_version >> 8) & 0xFF;
identifier[7] = dylib_cmd.dylib.current_version & 0xFF;
identifier[8] = (dylib_cmd.dylib.compatibility_version >> 24) & 0xFF;
identifier[9] = (dylib_cmd.dylib.compatibility_version >> 16) & 0xFF;
identifier[10] = (dylib_cmd.dylib.compatibility_version >> 8) & 0xFF;
identifier[11] = dylib_cmd.dylib.compatibility_version & 0xFF;
identifier[12] = identifier[13] = identifier[14] = identifier[15] = 0;
return true;
}
return false;
}
uint32_t MachoID::Adler32(int cpu_type) {
MachoWalker walker(path_, WalkerCB, this);
update_function_ = &MachoID::UpdateCRC;
crc_ = 0;
if (!walker.WalkHeader(cpu_type))
return 0;
return crc_;
}
bool MachoID::MD5(int cpu_type, unsigned char identifier[16]) {
MachoWalker walker(path_, WalkerCB, this);
update_function_ = &MachoID::UpdateMD5;
if (MD5_Init(&md5_context_)) {
if (!walker.WalkHeader(cpu_type))
return false;
MD5_Final(identifier, &md5_context_);
return true;
}
return false;
}
bool MachoID::SHA1(int cpu_type, unsigned char identifier[16]) {
MachoWalker walker(path_, WalkerCB, this);
update_function_ = &MachoID::UpdateSHA1;
if (SHA_Init(&sha1_context_)) {
if (!walker.WalkHeader(cpu_type))
return false;
SHA_Final(identifier, &sha1_context_);
return true;
}
return false;
}
// static
bool MachoID::WalkerCB(MachoWalker *walker, load_command *cmd, off_t offset,
bool swap, void *context) {
MachoID *macho_id = (MachoID *)context;
off_t seg_offset = 0;
size_t seg_size = 0;
if (cmd->cmd == LC_SEGMENT) {
struct segment_command seg;
if (!walker->ReadBytes(&seg, sizeof(seg), offset))
return false;
if (swap)
swap_segment_command(&seg, NXHostByteOrder());
seg_offset = seg.fileoff;
seg_size = seg.filesize;
} else if (cmd->cmd == LC_SEGMENT_64) {
struct segment_command_64 seg64;
if (!walker->ReadBytes(&seg64, sizeof(seg64), offset))
return false;
if (swap)
swap_segment_command_64(&seg64, NXHostByteOrder());
seg_offset = seg64.fileoff;
seg_size = seg64.filesize;
}
// If this was a non-zero segment, read the bytes, update the hash
if (seg_size) {
// Read 4k x 2 bytes at a time. This is faster than just 4k bytes, but
// doesn't seem to be an unreasonable size for the stack.
unsigned char buffer[4096 * 2];
size_t buffer_size;
off_t file_offset = seg_offset;
while (seg_size > 0) {
if (seg_size > sizeof(buffer)) {
buffer_size = sizeof(buffer);
seg_size -= buffer_size;
} else {
buffer_size = seg_size;
seg_size = 0;
}
if (!walker->ReadBytes(buffer, buffer_size, file_offset))
return false;
macho_id->Update(buffer, buffer_size);
file_offset += buffer_size;
}
}
// Continue processing
return true;
}
// static
bool MachoID::UUIDWalkerCB(MachoWalker *walker, load_command *cmd, off_t offset,
bool swap, void *context) {
if (cmd->cmd == LC_UUID) {
struct uuid_command *uuid_cmd = (struct uuid_command *)context;
if (!walker->ReadBytes(uuid_cmd, sizeof(struct uuid_command), offset))
return false;
if (swap)
swap_uuid_command(uuid_cmd, NXHostByteOrder());
return false;
}
// Continue processing
return true;
}
// static
bool MachoID::IDWalkerCB(MachoWalker *walker, load_command *cmd, off_t offset,
bool swap, void *context) {
if (cmd->cmd == LC_ID_DYLIB) {
struct dylib_command *dylib_cmd = (struct dylib_command *)context;
if (!walker->ReadBytes(dylib_cmd, sizeof(struct dylib_command), offset))
return false;
if (swap)
swap_dylib_command(dylib_cmd, NXHostByteOrder());
return false;
}
// Continue processing
return true;
}
} // namespace MacFileUtilities

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// 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
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (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_id.h: Functions to gather identifying information from a macho file
//
// Author: Dan Waylonis
#ifndef COMMON_MAC_MACHO_ID_H__
#define COMMON_MAC_MACHO_ID_H__
#include <limits.h>
#include <mach-o/loader.h>
#include <openssl/md5.h>
#include <openssl/sha.h>
namespace MacFileUtilities {
class MachoWalker;
class MachoID {
public:
MachoID(const char *path);
~MachoID();
// For the given |cpu_type|, return a UUID from the LC_UUID command.
// Return false if there isn't a LC_UUID command.
bool UUIDCommand(int cpu_type, unsigned char identifier[16]);
// For the given |cpu_type|, return a UUID from the LC_ID_DYLIB command.
// Return false if there isn't a LC_ID_DYLIB command.
bool IDCommand(int cpu_type, unsigned char identifier[16]);
// For the given |cpu_type|, return the Adler32 CRC for the mach-o data
// segment(s).
// Return 0 on error (e.g., if the file is not a mach-o file)
uint32_t Adler32(int cpu_type);
// For the given |cpu_type|, return the MD5 for the mach-o data segment(s).
// Return true on success, false otherwise
bool MD5(int cpu_type, unsigned char identifier[16]);
// For the given |cpu_type|, return the SHA1 for the mach-o data segment(s).
// Return true on success, false otherwise
bool SHA1(int cpu_type, unsigned char identifier[16]);
private:
// Signature of class member function to be called with data read from file
typedef void (MachoID::*UpdateFunction)(unsigned char *bytes, size_t size);
// Update the CRC value by examining |size| |bytes| and applying the algorithm
// to each byte.
void UpdateCRC(unsigned char *bytes, size_t size);
// Update the MD5 value by examining |size| |bytes| and applying the algorithm
// to each byte.
void UpdateMD5(unsigned char *bytes, size_t size);
// Update the SHA1 value by examining |size| |bytes| and applying the
// algorithm to each byte.
void UpdateSHA1(unsigned char *bytes, size_t size);
// Bottleneck for update routines
void Update(unsigned char *bytes, size_t size);
// The callback from the MachoWalker for CRC, MD5, and SHA1
static bool WalkerCB(MachoWalker *walker, load_command *cmd, off_t offset,
bool swap, void *context);
// The callback from the MachoWalker for LC_UUID
static bool UUIDWalkerCB(MachoWalker *walker, load_command *cmd, off_t offset,
bool swap, void *context);
// The callback from the MachoWalker for LC_ID_DYLIB
static bool IDWalkerCB(MachoWalker *walker, load_command *cmd, off_t offset,
bool swap, void *context);
// File path
char path_[PATH_MAX];
// File descriptor
int file_;
// The current crc value
uint32_t crc_;
// The MD5 context
MD5_CTX md5_context_;
// The SHA1 context
SHA_CTX sha1_context_;
// The current update to call from the Update callback
UpdateFunction update_function_;
};
} // namespace MacFileUtilities
#endif // COMMON_MAC_MACHO_ID_H__

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// 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
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (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/loader.h>
#include <mach-o/swap.h>
#include <unistd.h>
#include "common/mac/macho_walker.h"
namespace MacFileUtilities {
MachoWalker::MachoWalker(const char *path, LoadCommandCallback callback,
void *context)
: callback_(callback),
callback_context_(context) {
file_ = open(path, O_RDONLY);
}
MachoWalker::~MachoWalker() {
if (file_ != -1)
close(file_);
}
int MachoWalker::ValidateCPUType(int cpu_type) {
// If the user didn't specify, try to use the local architecture. If that
// fails, use the base type for the executable.
if (cpu_type == 0) {
const NXArchInfo *arch = NXGetLocalArchInfo();
if (arch)
cpu_type = arch->cputype;
else
#if __ppc__
cpu_type = CPU_TYPE_POWERPC;
#elif __i386__
cpu_type = CPU_TYPE_X86;
#else
#error Unknown architecture -- are you on a PDP-11?
#endif
}
return cpu_type;
}
bool MachoWalker::WalkHeader(int cpu_type) {
int valid_cpu_type = ValidateCPUType(cpu_type);
off_t offset;
if (FindHeader(valid_cpu_type, 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) {
return pread(file_, buffer, size, offset) == (ssize_t)size;
}
bool MachoWalker::FindHeader(int cpu_type, off_t &offset) {
int valid_cpu_type = ValidateCPUType(cpu_type);
// 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;
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
cpu_type_t header_cpu_type;
if (!ReadBytes(&header_cpu_type, sizeof(header_cpu_type), offset))
return false;
if (NXHostByteOrder() != NX_BigEndian)
header_cpu_type = NXSwapLong(header_cpu_type);
if (valid_cpu_type != header_cpu_type)
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)
swap_fat_header(&fat, NXHostByteOrder());
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)
swap_fat_arch(&arch, 1, NXHostByteOrder());
if (arch.cputype == valid_cpu_type) {
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)
swap_mach_header(&header, NXHostByteOrder());
return WalkHeaderCore(offset + sizeof(header), header.ncmds, swap);
}
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)
swap_mach_header_64(&header, NXHostByteOrder());
return WalkHeaderCore(offset + sizeof(header), header.ncmds, swap);
}
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)
swap_load_command(&cmd, NXHostByteOrder());
// Call the user callback
if (callback_ && !callback_(this, &cmd, offset, swap, callback_context_))
break;
offset += cmd.cmdsize;
}
return true;
}
} // namespace MacFileUtilities

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// 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
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (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.h: Iterate over the load commands in a mach-o file
//
// Author: Dan Waylonis
#ifndef COMMON_MAC_MACHO_WALKER_H__
#define COMMON_MAC_MACHO_WALKER_H__
#include <mach-o/loader.h>
#include <sys/types.h>
namespace MacFileUtilities {
class MachoWalker {
public:
// A callback function executed when a new load command is read. If no
// further processing of load commands is desired, return false. Otherwise,
// return true.
// |cmd| is the current command, and |offset| is the location relative to the
// beginning of the file (not header) where the command was read. If |swap|
// is set, then any command data (other than the returned load_command) should
// be swapped when read
typedef bool (*LoadCommandCallback)(MachoWalker *walker, load_command *cmd,
off_t offset, bool swap, void *context);
MachoWalker(const char *path, LoadCommandCallback callback, void *context);
MachoWalker(int file_descriptor, LoadCommandCallback callback, void *context);
~MachoWalker();
// Begin walking the header for |cpu_type|. If |cpu_type| is 0, then the
// native cpu type is used. Otherwise, accepted values are listed in
// /usr/include/mach/machine.h (e.g., CPU_TYPE_X86 or CPU_TYPE_POWERPC).
// Returns false if opening the file failed or if the |cpu_type| is not
// present in the file.
bool WalkHeader(int cpu_type);
// Locate (if any) the header offset for |cpu_type| and return in |offset|.
// Return true if found, false otherwise.
bool FindHeader(int cpu_type, off_t &offset);
// Read |size| bytes from the opened file at |offset| into |buffer|
bool ReadBytes(void *buffer, size_t size, off_t offset);
private:
// Validate the |cpu_type|
int ValidateCPUType(int cpu_type);
// Process an individual header starting at |offset| from the start of the
// file. Return true if successful, false otherwise.
bool WalkHeaderAtOffset(off_t offset);
bool WalkHeader64AtOffset(off_t offset);
// Bottleneck for walking the load commands
bool WalkHeaderCore(off_t offset, uint32_t number_of_commands, bool swap);
// File descriptor to the opened file
int file_;
// User specified callback & context
LoadCommandCallback callback_;
void *callback_context_;
};
} // namespace MacFileUtilities
#endif // COMMON_MAC_MACHO_WALKER_H__