cpptrace/src/platform/mach-o.hpp

252 lines
8.9 KiB
C++

#ifndef MACHO_HPP
#define MACHO_HPP
#include "common.hpp"
#include "utils.hpp"
#if IS_APPLE
// A number of mach-o functions are deprecated as of macos 13
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
#include <cstdio>
#include <cstring>
#include <type_traits>
#include <mach-o/loader.h>
#include <mach-o/swap.h>
#include <mach-o/fat.h>
#include <crt_externs.h>
#include <mach-o/nlist.h>
#include <mach-o/stab.h>
namespace cpptrace {
namespace detail {
static bool is_mach_o(uint32_t magic) {
switch(magic) {
case FAT_MAGIC:
case FAT_CIGAM:
case MH_MAGIC:
case MH_CIGAM:
case MH_MAGIC_64:
case MH_CIGAM_64:
return true;
default:
return false;
}
}
static bool is_fat_magic(uint32_t magic) {
return magic == FAT_MAGIC || magic == FAT_CIGAM;
}
// Based on https://github.com/AlexDenisov/segment_dumper/blob/master/main.c
// and https://lowlevelbits.org/parsing-mach-o-files/
static bool is_magic_64(uint32_t magic) {
return magic == MH_MAGIC_64 || magic == MH_CIGAM_64;
}
static bool should_swap_bytes(uint32_t magic) {
return magic == MH_CIGAM || magic == MH_CIGAM_64 || magic == FAT_CIGAM;
}
static void swap_mach_header(mach_header_64& header) {
swap_mach_header_64(&header, NX_UnknownByteOrder);
}
static void swap_mach_header(mach_header& header) {
swap_mach_header(&header, NX_UnknownByteOrder);
}
static void swap_segment_command(segment_command_64& segment) {
swap_segment_command_64(&segment, NX_UnknownByteOrder);
}
static void swap_segment_command(segment_command& segment) {
swap_segment_command(&segment, NX_UnknownByteOrder);
}
#ifdef __LP64__
#define LP(x) x##_64
#else
#define LP(x) x
#endif
template<std::size_t Bits>
static optional<uintptr_t> macho_get_text_vmaddr_mach(
FILE* obj_file,
const std::string& obj_path,
off_t offset,
bool should_swap,
bool allow_arch_mismatch
) {
static_assert(Bits == 32 || Bits == 64, "Unexpected Bits argument");
using Mach_Header = typename std::conditional<Bits == 32, mach_header, mach_header_64>::type;
using Segment_Command = typename std::conditional<Bits == 32, segment_command, segment_command_64>::type;
uint32_t ncmds;
off_t load_commands_offset = offset;
size_t header_size = sizeof(Mach_Header);
Mach_Header header = load_bytes<Mach_Header>(obj_file, offset);
if(should_swap) {
swap_mach_header(header);
}
thread_local static struct LP(mach_header)* mhp = _NSGetMachExecuteHeader();
//fprintf(
// stderr,
// "----> %d %d; %d %d\n",
// header.cputype,
// mhp->cputype,
// static_cast<cpu_subtype_t>(mhp->cpusubtype & ~CPU_SUBTYPE_MASK),
// header.cpusubtype
//);
if(
header.cputype != mhp->cputype ||
static_cast<cpu_subtype_t>(mhp->cpusubtype & ~CPU_SUBTYPE_MASK) != header.cpusubtype
) {
if(allow_arch_mismatch) {
return nullopt;
} else {
PANIC("Mach-O file cpu type and subtype do not match current machine " + obj_path);
}
}
ncmds = header.ncmds;
load_commands_offset += header_size;
// iterate load commands
off_t actual_offset = load_commands_offset;
for(uint32_t i = 0; i < ncmds; i++) {
load_command cmd = load_bytes<load_command>(obj_file, actual_offset);
if(should_swap) {
swap_load_command(&cmd, NX_UnknownByteOrder);
}
// TODO: This is a mistake? Need to check cmd.cmd == LC_SEGMENT_64 / cmd.cmd == LC_SEGMENT
Segment_Command segment = load_bytes<Segment_Command>(obj_file, actual_offset);
if(should_swap) {
swap_segment_command(segment);
}
if(strcmp(segment.segname, "__TEXT") == 0) {
return segment.vmaddr;
}
actual_offset += cmd.cmdsize;
}
// somehow no __TEXT section was found...
PANIC("Couldn't find __TEXT section while parsing Mach-O object");
return 0;
}
static uintptr_t macho_get_text_vmaddr_fat(FILE* obj_file, const std::string& obj_path, bool should_swap) {
size_t header_size = sizeof(fat_header);
size_t arch_size = sizeof(fat_arch);
fat_header header = load_bytes<fat_header>(obj_file, 0);
if(should_swap) {
swap_fat_header(&header, NX_UnknownByteOrder);
}
off_t arch_offset = (off_t)header_size;
optional<uintptr_t> text_vmaddr;
for(uint32_t i = 0; i < header.nfat_arch; i++) {
fat_arch arch = load_bytes<fat_arch>(obj_file, arch_offset);
if(should_swap) {
swap_fat_arch(&arch, 1, NX_UnknownByteOrder);
}
off_t mach_header_offset = (off_t)arch.offset;
arch_offset += arch_size;
uint32_t magic = load_bytes<uint32_t>(obj_file, mach_header_offset);
if(is_magic_64(magic)) {
text_vmaddr = macho_get_text_vmaddr_mach<64>(
obj_file,
obj_path,
mach_header_offset,
should_swap_bytes(magic),
true
);
} else {
text_vmaddr = macho_get_text_vmaddr_mach<32>(
obj_file,
obj_path,
mach_header_offset,
should_swap_bytes(magic),
true
);
}
if(text_vmaddr.has_value()) {
return text_vmaddr.unwrap();
}
}
// If this is reached... something went wrong. The cpu we're on wasn't found.
PANIC("Couldn't find appropriate architecture in fat Mach-O");
return 0;
}
static uintptr_t macho_get_text_vmaddr(const std::string& obj_path) {
//fprintf(stderr, "--%s--\n", obj_path.c_str());
auto file = raii_wrap(fopen(obj_path.c_str(), "rb"), file_deleter);
if(file == nullptr) {
throw file_error("Unable to read object file " + obj_path);
}
uint32_t magic = load_bytes<uint32_t>(file, 0);
VERIFY(is_mach_o(magic), "File is not Mach-O " + obj_path);
bool is_64 = is_magic_64(magic);
bool should_swap = should_swap_bytes(magic);
if(magic == FAT_MAGIC || magic == FAT_CIGAM) {
return macho_get_text_vmaddr_fat(file, obj_path, should_swap);
} else {
if(is_64) {
return macho_get_text_vmaddr_mach<64>(file, obj_path, 0, should_swap, false).unwrap();
} else {
return macho_get_text_vmaddr_mach<32>(file, obj_path, 0, should_swap, false).unwrap();
}
}
}
inline bool macho_is_fat(const std::string& obj_path) {
auto file = raii_wrap(fopen(obj_path.c_str(), "rb"), file_deleter);
if(file == nullptr) {
throw file_error("Unable to read object file " + obj_path);
}
uint32_t magic = load_bytes<uint32_t>(file, 0);
return is_fat_magic(magic);
}
// returns index of the appropriate mach-o binary in the universal binary
// TODO: Code duplication with macho_get_text_vmaddr_fat
inline unsigned get_fat_macho_index(const std::string& obj_path) {
auto file = raii_wrap(fopen(obj_path.c_str(), "rb"), file_deleter);
if(file == nullptr) {
throw file_error("Unable to read object file " + obj_path);
}
uint32_t magic = load_bytes<uint32_t>(file, 0);
VERIFY(is_fat_magic(magic));
bool should_swap = should_swap_bytes(magic);
size_t header_size = sizeof(fat_header);
size_t arch_size = sizeof(fat_arch);
fat_header header = load_bytes<fat_header>(file, 0);
if(should_swap) {
swap_fat_header(&header, NX_UnknownByteOrder);
}
off_t arch_offset = (off_t)header_size;
thread_local static struct LP(mach_header)* mhp = _NSGetMachExecuteHeader();
for(uint32_t i = 0; i < header.nfat_arch; i++) {
fat_arch arch = load_bytes<fat_arch>(file, arch_offset);
if(should_swap) {
swap_fat_arch(&arch, 1, NX_UnknownByteOrder);
}
arch_offset += arch_size;
if(
arch.cputype == mhp->cputype &&
static_cast<cpu_subtype_t>(mhp->cpusubtype & ~CPU_SUBTYPE_MASK) == arch.cpusubtype
) {
return i;
}
}
// If this is reached... something went wrong. The cpu we're on wasn't found.
PANIC("Couldn't find appropriate architecture in fat Mach-O");
}
}
}
#pragma GCC diagnostic pop
#endif
#endif