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kicad/thirdparty/sentry-native/external/crashpad/libunwind/src/AddressSpace.hpp

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Introduce sentry for crash data collection
2022-04-02 01:21:55 +00:00
//===------------------------- AddressSpace.hpp ---------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//
// Abstracts accessing local vs remote address spaces.
//
//===----------------------------------------------------------------------===//
#ifndef __ADDRESSSPACE_HPP__
#define __ADDRESSSPACE_HPP__
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "libunwind.h"
#include "config.h"
#include "dwarf2.h"
#include "EHHeaderParser.hpp"
#include "Registers.hpp"
#ifndef _LIBUNWIND_USE_DLADDR
#if !defined(_LIBUNWIND_IS_BAREMETAL) && !defined(_WIN32)
#define _LIBUNWIND_USE_DLADDR 1
#else
#define _LIBUNWIND_USE_DLADDR 0
#endif
#endif
#if _LIBUNWIND_USE_DLADDR
#include <dlfcn.h>
#if defined(__ELF__) && defined(_LIBUNWIND_LINK_DL_LIB)
#pragma comment(lib, "dl")
#endif
#endif
#if defined(_LIBUNWIND_ARM_EHABI)
struct EHABIIndexEntry {
uint32_t functionOffset;
uint32_t data;
};
#endif
#ifdef __APPLE__
#include <mach-o/dyld_images.h>
#include <mach-o/loader.h>
#include <mach-o/nlist.h>
#include <mach/mach_vm.h>
#include <mach/task_info.h>
struct dyld_unwind_sections
{
const struct mach_header* mh;
const void* dwarf_section;
uintptr_t dwarf_section_length;
const void* compact_unwind_section;
uintptr_t compact_unwind_section_length;
};
// In 10.7.0 or later, libSystem.dylib implements this function.
extern "C" bool _dyld_find_unwind_sections(void *, dyld_unwind_sections *);
#elif defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND) && defined(_LIBUNWIND_IS_BAREMETAL)
// When statically linked on bare-metal, the symbols for the EH table are looked
// up without going through the dynamic loader.
// The following linker script may be used to produce the necessary sections and symbols.
// Unless the --eh-frame-hdr linker option is provided, the section is not generated
// and does not take space in the output file.
//
// .eh_frame :
// {
// __eh_frame_start = .;
// KEEP(*(.eh_frame))
// __eh_frame_end = .;
// }
//
// .eh_frame_hdr :
// {
// KEEP(*(.eh_frame_hdr))
// }
//
// __eh_frame_hdr_start = SIZEOF(.eh_frame_hdr) > 0 ? ADDR(.eh_frame_hdr) : 0;
// __eh_frame_hdr_end = SIZEOF(.eh_frame_hdr) > 0 ? . : 0;
extern char __eh_frame_start;
extern char __eh_frame_end;
#if defined(_LIBUNWIND_SUPPORT_DWARF_INDEX)
extern char __eh_frame_hdr_start;
extern char __eh_frame_hdr_end;
#endif
#elif defined(_LIBUNWIND_ARM_EHABI) && defined(_LIBUNWIND_IS_BAREMETAL)
// When statically linked on bare-metal, the symbols for the EH table are looked
// up without going through the dynamic loader.
extern char __exidx_start;
extern char __exidx_end;
#elif defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND) && defined(_WIN32)
#include <windows.h>
#include <psapi.h>
#elif defined(_LIBUNWIND_USE_DL_ITERATE_PHDR) || \
defined(_LIBUNWIND_USE_DL_UNWIND_FIND_EXIDX)
#include <link.h>
#endif
namespace libunwind {
/// Used by findUnwindSections() to return info about needed sections.
struct UnwindInfoSections {
#if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND) || \
defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND) || \
defined(_LIBUNWIND_USE_DL_ITERATE_PHDR)
// No dso_base for SEH.
uintptr_t dso_base;
#endif
#if defined(_LIBUNWIND_USE_DL_ITERATE_PHDR)
uintptr_t text_segment_length;
#endif
#if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
uintptr_t dwarf_section;
uintptr_t dwarf_section_length;
#endif
#if defined(_LIBUNWIND_SUPPORT_DWARF_INDEX)
uintptr_t dwarf_index_section;
uintptr_t dwarf_index_section_length;
#endif
#if defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
uintptr_t compact_unwind_section;
uintptr_t compact_unwind_section_length;
#endif
#if defined(_LIBUNWIND_ARM_EHABI)
uintptr_t arm_section;
uintptr_t arm_section_length;
#endif
};
/// LocalAddressSpace is used as a template parameter to UnwindCursor when
/// unwinding a thread in the same process. The wrappers compile away,
/// making local unwinds fast.
class _LIBUNWIND_HIDDEN LocalAddressSpace {
public:
typedef uintptr_t pint_t;
typedef intptr_t sint_t;
uint8_t get8(pint_t addr) {
uint8_t val;
memcpy(&val, (void *)addr, sizeof(val));
return val;
}
uint16_t get16(pint_t addr) {
uint16_t val;
memcpy(&val, (void *)addr, sizeof(val));
return val;
}
uint32_t get32(pint_t addr) {
uint32_t val;
memcpy(&val, (void *)addr, sizeof(val));
return val;
}
uint64_t get64(pint_t addr) {
uint64_t val;
memcpy(&val, (void *)addr, sizeof(val));
return val;
}
double getDouble(pint_t addr) {
double val;
memcpy(&val, (void *)addr, sizeof(val));
return val;
}
v128 getVector(pint_t addr) {
v128 val;
memcpy(&val, (void *)addr, sizeof(val));
return val;
}
uintptr_t getP(pint_t addr);
uint64_t getRegister(pint_t addr);
static uint64_t getULEB128(pint_t &addr, pint_t end);
static int64_t getSLEB128(pint_t &addr, pint_t end);
pint_t getEncodedP(pint_t &addr, pint_t end, uint8_t encoding,
pint_t datarelBase = 0);
bool findFunctionName(pint_t addr, char *buf, size_t bufLen,
unw_word_t *offset);
bool findUnwindSections(pint_t targetAddr, UnwindInfoSections &info);
bool findOtherFDE(pint_t targetAddr, pint_t &fde);
static LocalAddressSpace sThisAddressSpace;
};
inline uintptr_t LocalAddressSpace::getP(pint_t addr) {
#if __SIZEOF_POINTER__ == 8
return get64(addr);
#else
return get32(addr);
#endif
}
inline uint64_t LocalAddressSpace::getRegister(pint_t addr) {
#if __SIZEOF_POINTER__ == 8 || defined(__mips64)
return get64(addr);
#else
return get32(addr);
#endif
}
/// Read a ULEB128 into a 64-bit word.
inline uint64_t LocalAddressSpace::getULEB128(pint_t &addr, pint_t end) {
const uint8_t *p = (uint8_t *)addr;
const uint8_t *pend = (uint8_t *)end;
uint64_t result = 0;
int bit = 0;
do {
uint64_t b;
if (p == pend)
_LIBUNWIND_ABORT("truncated uleb128 expression");
b = *p & 0x7f;
if (bit >= 64 || b << bit >> bit != b) {
_LIBUNWIND_ABORT("malformed uleb128 expression");
} else {
result |= b << bit;
bit += 7;
}
} while (*p++ >= 0x80);
addr = (pint_t) p;
return result;
}
/// Read a SLEB128 into a 64-bit word.
inline int64_t LocalAddressSpace::getSLEB128(pint_t &addr, pint_t end) {
const uint8_t *p = (uint8_t *)addr;
const uint8_t *pend = (uint8_t *)end;
int64_t result = 0;
int bit = 0;
uint8_t byte;
do {
if (p == pend)
_LIBUNWIND_ABORT("truncated sleb128 expression");
byte = *p++;
result |= (uint64_t)(byte & 0x7f) << bit;
bit += 7;
} while (byte & 0x80);
// sign extend negative numbers
if ((byte & 0x40) != 0 && bit < 64)
result |= (-1ULL) << bit;
addr = (pint_t) p;
return result;
}
inline LocalAddressSpace::pint_t
LocalAddressSpace::getEncodedP(pint_t &addr, pint_t end, uint8_t encoding,
pint_t datarelBase) {
pint_t startAddr = addr;
const uint8_t *p = (uint8_t *)addr;
pint_t result;
// first get value
switch (encoding & 0x0F) {
case DW_EH_PE_ptr:
result = getP(addr);
p += sizeof(pint_t);
addr = (pint_t) p;
break;
case DW_EH_PE_uleb128:
result = (pint_t)getULEB128(addr, end);
break;
case DW_EH_PE_udata2:
result = get16(addr);
p += 2;
addr = (pint_t) p;
break;
case DW_EH_PE_udata4:
result = get32(addr);
p += 4;
addr = (pint_t) p;
break;
case DW_EH_PE_udata8:
result = (pint_t)get64(addr);
p += 8;
addr = (pint_t) p;
break;
case DW_EH_PE_sleb128:
result = (pint_t)getSLEB128(addr, end);
break;
case DW_EH_PE_sdata2:
// Sign extend from signed 16-bit value.
result = (pint_t)(int16_t)get16(addr);
p += 2;
addr = (pint_t) p;
break;
case DW_EH_PE_sdata4:
// Sign extend from signed 32-bit value.
result = (pint_t)(int32_t)get32(addr);
p += 4;
addr = (pint_t) p;
break;
case DW_EH_PE_sdata8:
result = (pint_t)get64(addr);
p += 8;
addr = (pint_t) p;
break;
default:
_LIBUNWIND_ABORT("unknown pointer encoding");
}
// then add relative offset
switch (encoding & 0x70) {
case DW_EH_PE_absptr:
// do nothing
break;
case DW_EH_PE_pcrel:
result += startAddr;
break;
case DW_EH_PE_textrel:
_LIBUNWIND_ABORT("DW_EH_PE_textrel pointer encoding not supported");
break;
case DW_EH_PE_datarel:
// DW_EH_PE_datarel is only valid in a few places, so the parameter has a
// default value of 0, and we abort in the event that someone calls this
// function with a datarelBase of 0 and DW_EH_PE_datarel encoding.
if (datarelBase == 0)
_LIBUNWIND_ABORT("DW_EH_PE_datarel is invalid with a datarelBase of 0");
result += datarelBase;
break;
case DW_EH_PE_funcrel:
_LIBUNWIND_ABORT("DW_EH_PE_funcrel pointer encoding not supported");
break;
case DW_EH_PE_aligned:
_LIBUNWIND_ABORT("DW_EH_PE_aligned pointer encoding not supported");
break;
default:
_LIBUNWIND_ABORT("unknown pointer encoding");
break;
}
if (encoding & DW_EH_PE_indirect)
result = getP(result);
return result;
}
#if defined(_LIBUNWIND_USE_DL_ITERATE_PHDR)
// The ElfW() macro for pointer-size independent ELF header traversal is not
// provided by <link.h> on some systems (e.g., FreeBSD). On these systems the
// data structures are just called Elf_XXX. Define ElfW() locally.
#if !defined(ElfW)
#define ElfW(type) Elf_##type
#endif
#if !defined(Elf_Half)
typedef ElfW(Half) Elf_Half;
#endif
#if !defined(Elf_Phdr)
typedef ElfW(Phdr) Elf_Phdr;
#endif
#if !defined(Elf_Addr)
typedef ElfW(Addr) Elf_Addr;
#endif
static Elf_Addr calculateImageBase(struct dl_phdr_info *pinfo) {
Elf_Addr image_base = pinfo->dlpi_addr;
#if defined(__ANDROID__) && __ANDROID_API__ < 18
if (image_base == 0) {
// Normally, an image base of 0 indicates a non-PIE executable. On
// versions of Android prior to API 18, the dynamic linker reported a
// dlpi_addr of 0 for PIE executables. Compute the true image base
// using the PT_PHDR segment.
// See https://github.com/android/ndk/issues/505.
for (Elf_Half i = 0; i < pinfo->dlpi_phnum; i++) {
const Elf_Phdr *phdr = &pinfo->dlpi_phdr[i];
if (phdr->p_type == PT_PHDR) {
image_base = reinterpret_cast<Elf_Addr>(pinfo->dlpi_phdr) -
phdr->p_vaddr;
break;
}
}
}
#endif
return image_base;
}
struct _LIBUNWIND_HIDDEN dl_iterate_cb_data {
LocalAddressSpace *addressSpace;
UnwindInfoSections *sects;
uintptr_t targetAddr;
};
#if defined(_LIBUNWIND_USE_FRAME_HEADER_CACHE)
#include "FrameHeaderCache.hpp"
// Typically there is one cache per process, but when libunwind is built as a
// hermetic static library, then each shared object may have its own cache.
static FrameHeaderCache TheFrameHeaderCache;
#endif
static bool checkAddrInSegment(const Elf_Phdr *phdr, size_t image_base,
dl_iterate_cb_data *cbdata) {
if (phdr->p_type == PT_LOAD) {
uintptr_t begin = image_base + phdr->p_vaddr;
uintptr_t end = begin + phdr->p_memsz;
if (cbdata->targetAddr >= begin && cbdata->targetAddr < end) {
cbdata->sects->dso_base = begin;
cbdata->sects->text_segment_length = phdr->p_memsz;
return true;
}
}
return false;
}
static bool checkForUnwindInfoSegment(const Elf_Phdr *phdr, size_t image_base,
dl_iterate_cb_data *cbdata) {
#if defined(_LIBUNWIND_SUPPORT_DWARF_INDEX)
if (phdr->p_type == PT_GNU_EH_FRAME) {
EHHeaderParser<LocalAddressSpace>::EHHeaderInfo hdrInfo;
uintptr_t eh_frame_hdr_start = image_base + phdr->p_vaddr;
cbdata->sects->dwarf_index_section = eh_frame_hdr_start;
cbdata->sects->dwarf_index_section_length = phdr->p_memsz;
if (EHHeaderParser<LocalAddressSpace>::decodeEHHdr(
*cbdata->addressSpace, eh_frame_hdr_start, phdr->p_memsz,
hdrInfo)) {
// .eh_frame_hdr records the start of .eh_frame, but not its size.
// Rely on a zero terminator to find the end of the section.
cbdata->sects->dwarf_section = hdrInfo.eh_frame_ptr;
cbdata->sects->dwarf_section_length = UINTPTR_MAX;
return true;
}
}
return false;
#elif defined(_LIBUNWIND_ARM_EHABI)
if (phdr->p_type == PT_ARM_EXIDX) {
uintptr_t exidx_start = image_base + phdr->p_vaddr;
cbdata->sects->arm_section = exidx_start;
cbdata->sects->arm_section_length = phdr->p_memsz;
return true;
}
return false;
#else
#error Need one of _LIBUNWIND_SUPPORT_DWARF_INDEX or _LIBUNWIND_ARM_EHABI
#endif
}
static int findUnwindSectionsByPhdr(struct dl_phdr_info *pinfo,
size_t pinfo_size, void *data) {
auto cbdata = static_cast<dl_iterate_cb_data *>(data);
if (pinfo->dlpi_phnum == 0 || cbdata->targetAddr < pinfo->dlpi_addr)
return 0;
#if defined(_LIBUNWIND_USE_FRAME_HEADER_CACHE)
if (TheFrameHeaderCache.find(pinfo, pinfo_size, data))
return 1;
#else
// Avoid warning about unused variable.
(void)pinfo_size;
#endif
Elf_Addr image_base = calculateImageBase(pinfo);
// Most shared objects seen in this callback function likely don't contain the
// target address, so optimize for that. Scan for a matching PT_LOAD segment
// first and bail when it isn't found.
bool found_text = false;
for (Elf_Half i = 0; i < pinfo->dlpi_phnum; ++i) {
if (checkAddrInSegment(&pinfo->dlpi_phdr[i], image_base, cbdata)) {
found_text = true;
break;
}
}
if (!found_text)
return 0;
// PT_GNU_EH_FRAME and PT_ARM_EXIDX are usually near the end. Iterate
// backward.
bool found_unwind = false;
for (Elf_Half i = pinfo->dlpi_phnum; i > 0; i--) {
const Elf_Phdr *phdr = &pinfo->dlpi_phdr[i - 1];
if (checkForUnwindInfoSegment(phdr, image_base, cbdata)) {
found_unwind = true;
break;
}
}
if (!found_unwind)
return 0;
#if defined(_LIBUNWIND_USE_FRAME_HEADER_CACHE)
TheFrameHeaderCache.add(cbdata->sects);
#endif
return 1;
}
#endif // defined(_LIBUNWIND_USE_DL_ITERATE_PHDR)
inline bool LocalAddressSpace::findUnwindSections(pint_t targetAddr,
UnwindInfoSections &info) {
#ifdef __APPLE__
dyld_unwind_sections dyldInfo;
if (_dyld_find_unwind_sections((void *)targetAddr, &dyldInfo)) {
info.dso_base = (uintptr_t)dyldInfo.mh;
#if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
info.dwarf_section = (uintptr_t)dyldInfo.dwarf_section;
info.dwarf_section_length = dyldInfo.dwarf_section_length;
#endif
info.compact_unwind_section = (uintptr_t)dyldInfo.compact_unwind_section;
info.compact_unwind_section_length = dyldInfo.compact_unwind_section_length;
return true;
}
#elif defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND) && defined(_LIBUNWIND_IS_BAREMETAL)
info.dso_base = 0;
// Bare metal is statically linked, so no need to ask the dynamic loader
info.dwarf_section_length = (uintptr_t)(&__eh_frame_end - &__eh_frame_start);
info.dwarf_section = (uintptr_t)(&__eh_frame_start);
_LIBUNWIND_TRACE_UNWINDING("findUnwindSections: section %p length %p",
(void *)info.dwarf_section, (void *)info.dwarf_section_length);
#if defined(_LIBUNWIND_SUPPORT_DWARF_INDEX)
info.dwarf_index_section = (uintptr_t)(&__eh_frame_hdr_start);
info.dwarf_index_section_length = (uintptr_t)(&__eh_frame_hdr_end - &__eh_frame_hdr_start);
_LIBUNWIND_TRACE_UNWINDING("findUnwindSections: index section %p length %p",
(void *)info.dwarf_index_section, (void *)info.dwarf_index_section_length);
#endif
if (info.dwarf_section_length)
return true;
#elif defined(_LIBUNWIND_ARM_EHABI) && defined(_LIBUNWIND_IS_BAREMETAL)
// Bare metal is statically linked, so no need to ask the dynamic loader
info.arm_section = (uintptr_t)(&__exidx_start);
info.arm_section_length = (uintptr_t)(&__exidx_end - &__exidx_start);
_LIBUNWIND_TRACE_UNWINDING("findUnwindSections: section %p length %p",
(void *)info.arm_section, (void *)info.arm_section_length);
if (info.arm_section && info.arm_section_length)
return true;
#elif defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND) && defined(_WIN32)
HMODULE mods[1024];
HANDLE process = GetCurrentProcess();
DWORD needed;
if (!EnumProcessModules(process, mods, sizeof(mods), &needed)) {
DWORD err = GetLastError();
_LIBUNWIND_TRACE_UNWINDING("findUnwindSections: EnumProcessModules failed, "
"returned error %d", (int)err);
return false;
}
for (unsigned i = 0; i < (needed / sizeof(HMODULE)); i++) {
PIMAGE_DOS_HEADER pidh = (PIMAGE_DOS_HEADER)mods[i];
PIMAGE_NT_HEADERS pinh = (PIMAGE_NT_HEADERS)((BYTE *)pidh + pidh->e_lfanew);
PIMAGE_FILE_HEADER pifh = (PIMAGE_FILE_HEADER)&pinh->FileHeader;
PIMAGE_SECTION_HEADER pish = IMAGE_FIRST_SECTION(pinh);
bool found_obj = false;
bool found_hdr = false;
info.dso_base = (uintptr_t)mods[i];
for (unsigned j = 0; j < pifh->NumberOfSections; j++, pish++) {
uintptr_t begin = pish->VirtualAddress + (uintptr_t)mods[i];
uintptr_t end = begin + pish->Misc.VirtualSize;
if (!strncmp((const char *)pish->Name, ".text",
IMAGE_SIZEOF_SHORT_NAME)) {
if (targetAddr >= begin && targetAddr < end)
found_obj = true;
} else if (!strncmp((const char *)pish->Name, ".eh_frame",
IMAGE_SIZEOF_SHORT_NAME)) {
info.dwarf_section = begin;
info.dwarf_section_length = pish->Misc.VirtualSize;
found_hdr = true;
}
if (found_obj && found_hdr)
return true;
}
}
return false;
#elif defined(_LIBUNWIND_SUPPORT_SEH_UNWIND) && defined(_WIN32)
// Don't even bother, since Windows has functions that do all this stuff
// for us.
(void)targetAddr;
(void)info;
return true;
#elif defined(_LIBUNWIND_USE_DL_UNWIND_FIND_EXIDX)
int length = 0;
info.arm_section =
(uintptr_t)dl_unwind_find_exidx((_Unwind_Ptr)targetAddr, &length);
info.arm_section_length = (uintptr_t)length * sizeof(EHABIIndexEntry);
if (info.arm_section && info.arm_section_length)
return true;
#elif defined(_LIBUNWIND_USE_DL_ITERATE_PHDR)
dl_iterate_cb_data cb_data = {this, &info, targetAddr};
int found = dl_iterate_phdr(findUnwindSectionsByPhdr, &cb_data);
return static_cast<bool>(found);
#endif
return false;
}
inline bool LocalAddressSpace::findOtherFDE(pint_t targetAddr, pint_t &fde) {
// TO DO: if OS has way to dynamically register FDEs, check that.
(void)targetAddr;
(void)fde;
return false;
}
inline bool LocalAddressSpace::findFunctionName(pint_t addr, char *buf,
size_t bufLen,
unw_word_t *offset) {
#if _LIBUNWIND_USE_DLADDR
Dl_info dyldInfo;
if (dladdr((void *)addr, &dyldInfo)) {
if (dyldInfo.dli_sname != NULL) {
snprintf(buf, bufLen, "%s", dyldInfo.dli_sname);
*offset = (addr - (pint_t) dyldInfo.dli_saddr);
return true;
}
}
#else
(void)addr;
(void)buf;
(void)bufLen;
(void)offset;
#endif
return false;
}
struct found_mach_info {
struct mach_header_64 header;
struct segment_command_64 segment;
uintptr_t ptr_after_segment;
uintptr_t load_addr;
uintptr_t slide;
uintptr_t text_size;
bool header_valid;
bool segment_valid;
};
/// RemoteAddressSpace is used as a template parameter to UnwindCursor when
/// unwinding a thread in the another process.
/// In theory, the other process can be a different endianness and a different
/// pointer size which was handled by the P template parameter in the original
/// implementation.
/// However, we assume that we are only dealing with x64 and arm64 here, which
/// have both the same endianness and pointer size.
class RemoteAddressSpace {
public:
RemoteAddressSpace(task_t task) : task_(task), last_found_image(found_mach_info()) {}
static void *operator new(size_t, RemoteAddressSpace *p) { return p; }
typedef uintptr_t pint_t;
typedef intptr_t sint_t;
uint8_t get8(pint_t addr) {
uint8_t val = 0;
memcpy_from_remote(&val, (void *)addr, sizeof(val));
return val;
}
uint16_t get16(pint_t addr) {
uint16_t val = 0;
memcpy_from_remote(&val, (void *)addr, sizeof(val));
return val;
}
uint32_t get32(pint_t addr) {
uint32_t val = 0;
memcpy_from_remote(&val, (void *)addr, sizeof(val));
return val;
}
uint64_t get64(pint_t addr) {
uint64_t val = 0;
memcpy_from_remote(&val, (void *)addr, sizeof(val));
return val;
}
double getDouble(pint_t addr) {
double val = 0;
memcpy_from_remote(&val, (void *)addr, sizeof(val));
return val;
}
v128 getVector(pint_t addr) {
v128 val = {0};
memcpy_from_remote(&val, (void *)addr, sizeof(val));
return val;
}
uintptr_t getP(pint_t addr) {
return get64(addr);
}
uint64_t getRegister(pint_t addr) {
return get64(addr);
}
uint64_t getULEB128(pint_t &addr, pint_t end);
int64_t getSLEB128(pint_t &addr, pint_t end);
pint_t getEncodedP(pint_t &addr, pint_t end, uint8_t encoding,
pint_t datarelBase = 0);
bool findFunctionName(pint_t addr, char *buf, size_t bufLen,
unw_word_t *offset);
bool findUnwindSections(pint_t targetAddr, UnwindInfoSections &info);
bool findOtherFDE(pint_t targetAddr, pint_t &fde);
private:
kern_return_t memcpy_from_remote(void *dest, void *src, size_t size);
// Finds the mach image that contains `targetAddr`, and saves it and the
// corresponding `segment` in the local `last_found_image`, returning `true`
// on success.
bool findMachSegment(pint_t targetAddr, const char *segment);
// Similar to the above, except it assumes the `header` of `last_found_image`
// is valid.
bool findMachSegmentInImage(pint_t targetAddr, const char *segment);
task_t task_;
found_mach_info last_found_image;
};
uint64_t RemoteAddressSpace::getULEB128(pint_t &addr, pint_t end) {
uintptr_t size = (end - addr);
char buf[16] = {0};
memcpy_from_remote(buf, (void *)addr, 16);
LocalAddressSpace::pint_t laddr = (LocalAddressSpace::pint_t)buf;
LocalAddressSpace::pint_t sladdr = laddr;
uint64_t result = LocalAddressSpace::getULEB128(laddr, laddr + size);
addr += (laddr - sladdr);
return result;
}
int64_t RemoteAddressSpace::getSLEB128(pint_t &addr, pint_t end) {
uintptr_t size = (end - addr);
char buf[16] = {0};
memcpy_from_remote(buf, (void *)addr, 16);
LocalAddressSpace::pint_t laddr =
(LocalAddressSpace::pint_t)buf;
LocalAddressSpace::pint_t sladdr = laddr;
int64_t result = LocalAddressSpace::getSLEB128(laddr, laddr + size);
addr += (laddr - sladdr);
return result;
}
kern_return_t RemoteAddressSpace::memcpy_from_remote(void *dest, void *src, size_t size) {
size_t read_bytes = 0;
kern_return_t kr = mach_vm_read_overwrite(
task_, (mach_vm_address_t)src, (mach_vm_size_t)size,
(mach_vm_address_t)dest, (mach_vm_size_t *)&read_bytes);
return kr;
}
// we needed to copy this whole function since we can’t reuse the one from
// `LocalAddressSpace`. :-(
RemoteAddressSpace::pint_t
RemoteAddressSpace::getEncodedP(pint_t &addr, pint_t end, uint8_t encoding,
pint_t datarelBase) {
pint_t startAddr = addr;
const uint8_t *p = (uint8_t *)addr;
pint_t result;
// first get value
switch (encoding & 0x0F) {
case DW_EH_PE_ptr:
result = getP(addr);
p += sizeof(pint_t);
addr = (pint_t)p;
break;
case DW_EH_PE_uleb128:
result = (pint_t)getULEB128(addr, end);
break;
case DW_EH_PE_udata2:
result = get16(addr);
p += 2;
addr = (pint_t)p;
break;
case DW_EH_PE_udata4:
result = get32(addr);
p += 4;
addr = (pint_t)p;
break;
case DW_EH_PE_udata8:
result = (pint_t)get64(addr);
p += 8;
addr = (pint_t)p;
break;
case DW_EH_PE_sleb128:
result = (pint_t)getSLEB128(addr, end);
break;
case DW_EH_PE_sdata2:
// Sign extend from signed 16-bit value.
result = (pint_t)(int16_t)get16(addr);
p += 2;
addr = (pint_t)p;
break;
case DW_EH_PE_sdata4:
// Sign extend from signed 32-bit value.
result = (pint_t)(int32_t)get32(addr);
p += 4;
addr = (pint_t)p;
break;
case DW_EH_PE_sdata8:
result = (pint_t)get64(addr);
p += 8;
addr = (pint_t)p;
break;
default:
_LIBUNWIND_ABORT("unknown pointer encoding");
}
// then add relative offset
switch (encoding & 0x70) {
case DW_EH_PE_absptr:
// do nothing
break;
case DW_EH_PE_pcrel:
result += startAddr;
break;
case DW_EH_PE_textrel:
_LIBUNWIND_ABORT("DW_EH_PE_textrel pointer encoding not supported");
break;
case DW_EH_PE_datarel:
// DW_EH_PE_datarel is only valid in a few places, so the parameter has a
// default value of 0, and we abort in the event that someone calls this
// function with a datarelBase of 0 and DW_EH_PE_datarel encoding.
if (datarelBase == 0)
_LIBUNWIND_ABORT("DW_EH_PE_datarel is invalid with a datarelBase of 0");
result += datarelBase;
break;
case DW_EH_PE_funcrel:
_LIBUNWIND_ABORT("DW_EH_PE_funcrel pointer encoding not supported");
break;
case DW_EH_PE_aligned:
_LIBUNWIND_ABORT("DW_EH_PE_aligned pointer encoding not supported");
break;
default:
_LIBUNWIND_ABORT("unknown pointer encoding");
break;
}
if (encoding & DW_EH_PE_indirect)
result = getP(result);
return result;
}
bool RemoteAddressSpace::findMachSegment(pint_t targetAddr,
const char *segment) {
if (!last_found_image.header_valid || !(last_found_image.load_addr <= targetAddr && last_found_image.load_addr + last_found_image.text_size > targetAddr)) {
last_found_image.segment_valid = false;
// enumerate all images and find the one we are looking for.
task_dyld_info_data_t task_dyld_info;
mach_msg_type_number_t count = TASK_DYLD_INFO_COUNT;
if (task_info(task_, TASK_DYLD_INFO, (task_info_t)&task_dyld_info,
&count) != KERN_SUCCESS) {
return false;
}
if (task_dyld_info.all_image_info_format != TASK_DYLD_ALL_IMAGE_INFO_64) {
return false;
}
dyld_all_image_infos all_images_info;
if (memcpy_from_remote(&all_images_info,
(void *)task_dyld_info.all_image_info_addr,
sizeof(dyld_all_image_infos)) != KERN_SUCCESS) {
return false;
};
for (size_t i = 0; i < all_images_info.infoArrayCount; i++) {
dyld_image_info image;
if (memcpy_from_remote(&image, (void *)&all_images_info.infoArray[i],
sizeof(dyld_image_info)) != KERN_SUCCESS) {
continue;
};
// image is out of range of `targetAddr`
if ((pint_t)image.imageLoadAddress > targetAddr) {
continue;
}
if (memcpy_from_remote(&last_found_image.header,
(void *)image.imageLoadAddress,
sizeof(struct mach_header_64)) != KERN_SUCCESS) {
continue;
};
if (last_found_image.header.magic != MH_MAGIC_64) {
continue;
}
last_found_image.load_addr = (size_t)image.imageLoadAddress;
if (findMachSegmentInImage(targetAddr, "__TEXT")) {
last_found_image.header_valid = true;
break;
}
}
}
if (!last_found_image.header_valid) {
return false;
}
if (!last_found_image.segment_valid ||
strcmp(last_found_image.segment.segname, segment) != 0) {
// search for the segment in the image
if (!findMachSegmentInImage(targetAddr, segment)) {
return false;
}
}
return true;
}
bool RemoteAddressSpace::findMachSegmentInImage(pint_t targetAddr, const char*segment) {
// This section here is basically a remote-rewrite of
// `dyld_exceptions_init` from:
// https://opensource.apple.com/source/dyld/dyld-195.6/src/dyldExceptions.c.auto.html
struct load_command cmd;
pint_t cmd_ptr =
(pint_t)last_found_image.load_addr + sizeof(struct mach_header_64);
bool found_text = false;
bool found_searched = false;
for (size_t c = 0; c < last_found_image.header.ncmds; c++) {
if (memcpy_from_remote(&cmd, (void *)cmd_ptr,
sizeof(struct load_command)) != KERN_SUCCESS) {
return false;
};
if (cmd.cmd == LC_SEGMENT_64) {
struct segment_command_64 seg;
if (memcpy_from_remote(&seg, (void *)cmd_ptr,
sizeof(struct segment_command_64)) !=
KERN_SUCCESS) {
return false;
};
if (strcmp(seg.segname, "__TEXT") == 0) {
pint_t slide = last_found_image.load_addr - seg.vmaddr;
// text section out of range of `targetAddr`
pint_t text_end = seg.vmaddr + seg.vmsize + slide;
if (text_end < targetAddr) {
return false;
}
last_found_image.slide = slide;
last_found_image.text_size = seg.vmsize;
found_text = true;
}
if (strncmp(seg.segname, segment, 16) == 0) {
pint_t sect_ptr = cmd_ptr + sizeof(struct segment_command_64);
last_found_image.segment_valid = true;
last_found_image.segment = seg;
last_found_image.ptr_after_segment = sect_ptr;
found_searched = true;
}
if (found_text && found_searched) {
return true;
}
}
cmd_ptr += cmd.cmdsize;
}
return false;
}
inline bool RemoteAddressSpace::findUnwindSections(pint_t targetAddr,
UnwindInfoSections &info) {
if (!findMachSegment(targetAddr, "__TEXT")) {
return false;
}
info.dso_base = last_found_image.load_addr;
info.dwarf_section = 0;
info.compact_unwind_section = 0;
for (size_t s = 0; s < last_found_image.segment.nsects; s++) {
struct section_64 sect;
if (memcpy_from_remote(&sect,
(void *)(last_found_image.ptr_after_segment +
s * sizeof(struct section_64)),
sizeof(struct section_64)) != KERN_SUCCESS) {
continue;
};
if (strcmp(sect.sectname, "__eh_frame") == 0) {
info.dwarf_section = sect.addr + last_found_image.slide;
info.dwarf_section_length = sect.size;
} else if (strcmp(sect.sectname, "__unwind_info") == 0) {
info.compact_unwind_section = sect.addr + last_found_image.slide;
info.compact_unwind_section_length = sect.size;
}
}
return true;
}
bool RemoteAddressSpace::findOtherFDE(pint_t targetAddr, pint_t & fde) {
// TO DO: if OS has way to dynamically register FDEs, check that.
(void)targetAddr;
(void)fde;
return false;
}
bool RemoteAddressSpace::findFunctionName(pint_t addr, char *buf,
size_t bufLen, unw_word_t *offset) {
// This is essentially a remote re-implementation of this snippet:
// https://gist.github.com/integeruser/b0d3ea6c4e8387d036acf6c77c0ec406
if (!findMachSegment(addr, "__TEXT")) {
return false;
}
struct load_command cmd;
pint_t cmd_ptr =
(pint_t)last_found_image.load_addr + sizeof(struct mach_header_64);
for (size_t c = 0; c < last_found_image.header.ncmds; c++) {
if (memcpy_from_remote(&cmd, (void *)cmd_ptr,
sizeof(struct load_command)) != KERN_SUCCESS) {
return false;
};
if (cmd.cmd == LC_SYMTAB) {
struct symtab_command seg;
if (memcpy_from_remote(&seg, (void *)cmd_ptr,
sizeof(struct symtab_command)) != KERN_SUCCESS) {
return false;
};
pint_t strtab = last_found_image.load_addr + seg.stroff;
pint_t nearest_sym = 0;
for (size_t s = 0; s < seg.nsyms; s++) {
struct nlist_64 nlist;
if (memcpy_from_remote(&nlist,
(void *)(last_found_image.load_addr +
seg.symoff +
s * sizeof(struct nlist_64)),
sizeof(struct nlist_64)) != KERN_SUCCESS) {
return false;
};
if ((nlist.n_type & N_STAB) != 0 || (nlist.n_type & N_TYPE) != N_SECT ||
nlist.n_un.n_strx == 0) {
continue;
}
pint_t sym_addr = nlist.n_value + last_found_image.slide;
if (sym_addr > nearest_sym && sym_addr < addr) {
pint_t symbol_start = strtab + nlist.n_un.n_strx;
pint_t bytes_to_copy = strtab + seg.strsize - symbol_start;
if (bytes_to_copy > bufLen) {
bytes_to_copy = bufLen;
}
if (memcpy_from_remote(buf, (void *)(symbol_start), bytes_to_copy) !=
KERN_SUCCESS) {
return false;
}
buf[bufLen - 1] = '\0';
nearest_sym = sym_addr;
}
}
if (nearest_sym > 0) {
return true;
}
break;
}
cmd_ptr += cmd.cmdsize;
}
(void)offset;
return false;
}
} // namespace libunwind
#endif // __ADDRESSSPACE_HPP__