swift-mirror/stdlib/public/runtime/ImageInspectionMachO.cpp

//===--- ImageInspectionMachO.cpp - Mach-O image inspection ---------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
///
/// \file
///
/// This file includes routines that interact with dyld on Mach-O-based
/// platforms to extract runtime metadata embedded in images generated by the
/// Swift compiler.
///
//===----------------------------------------------------------------------===//

#if defined(__APPLE__) && defined(__MACH__) &&                                 \
    !defined(SWIFT_RUNTIME_STATIC_IMAGE_INSPECTION)

#include "ImageInspection.h"
#include "ImageInspectionCommon.h"
#include "swift/Runtime/Config.h"
#include <mach-o/dyld.h>
#include <mach-o/getsect.h>
#include <objc/runtime.h>
#include <assert.h>
#include <dlfcn.h>

using namespace swift;

namespace {

constexpr const char ProtocolsSection[] = MachOProtocolsSection;
constexpr const char ProtocolConformancesSection[] =
    MachOProtocolConformancesSection;
constexpr const char TypeMetadataRecordSection[] =
    MachOTypeMetadataRecordSection;
constexpr const char DynamicReplacementSection[] =
    MachODynamicReplacementSection;
constexpr const char DynamicReplacementSomeSection[] =
    MachODynamicReplacementSomeSection;
constexpr const char AccessibleFunctionsSection[] =
    MachOAccessibleFunctionsSection;
constexpr const char TextSegment[] = MachOTextSegment;

#if __POINTER_WIDTH__ == 64
using mach_header_platform = mach_header_64;
#else
using mach_header_platform = mach_header;
#endif

template <const char *SEGMENT_NAME, const char *SECTION_NAME,
         void CONSUME_BLOCK(const void *baseAddress,
                            const void *start, uintptr_t size)>
void addImageCallback(const mach_header *mh) {
#if __POINTER_WIDTH__ == 64
  assert(mh->magic == MH_MAGIC_64 && "loaded non-64-bit image?!");
#endif
  
  // Look for a __swift5_proto section.
  unsigned long size;
  const uint8_t *section =
  getsectiondata(reinterpret_cast<const mach_header_platform *>(mh),
                 SEGMENT_NAME, SECTION_NAME,
                 &size);
  
  if (!section)
    return;
  
  CONSUME_BLOCK(mh, section, size);
}
template <const char *SEGMENT_NAME, const char *SECTION_NAME,
         void CONSUME_BLOCK(const void *baseAddress,
                            const void *start, uintptr_t size)>
void addImageCallback(const mach_header *mh, intptr_t vmaddr_slide) {
  addImageCallback<SEGMENT_NAME, SECTION_NAME, CONSUME_BLOCK>(mh);
}

template <const char *SEGMENT_NAME, const char *SECTION_NAME,
          const char *SEGMENT_NAME2, const char *SECTION_NAME2,
          void CONSUME_BLOCK(const void *baseAddress,
                             const void *start, uintptr_t size,
                             const void *start2, uintptr_t size2)>
void addImageCallback2Sections(const mach_header *mh) {
#if __POINTER_WIDTH__ == 64
  assert(mh->magic == MH_MAGIC_64 && "loaded non-64-bit image?!");
#endif

  // Look for a section.
  unsigned long size;
  const uint8_t *section =
  getsectiondata(reinterpret_cast<const mach_header_platform *>(mh),
                 SEGMENT_NAME, SECTION_NAME,
                 &size);

  if (!section)
    return;

  // Look for another section.
  unsigned long size2;
  const uint8_t *section2 =
  getsectiondata(reinterpret_cast<const mach_header_platform *>(mh),
                 SEGMENT_NAME2, SECTION_NAME2,
                 &size2);
  if (!section2)
    size2 = 0;

  CONSUME_BLOCK(mh, section, size, section2, size2);
}
template <const char *SEGMENT_NAME, const char *SECTION_NAME,
          const char *SEGMENT_NAME2, const char *SECTION_NAME2,
          void CONSUME_BLOCK(const void *baseAddress,
                             const void *start, uintptr_t size,
                             const void *start2, uintptr_t size2)>
void addImageCallback2Sections(const mach_header *mh, intptr_t vmaddr_slide) {
  addImageCallback2Sections<SEGMENT_NAME, SECTION_NAME,
                            SEGMENT_NAME2, SECTION_NAME2,
                            CONSUME_BLOCK>(mh);
}

} // end anonymous namespace

#if OBJC_ADDLOADIMAGEFUNC_DEFINED && SWIFT_OBJC_INTEROP
#define REGISTER_FUNC(...)                                               \
  if (__builtin_available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)) { \
    objc_addLoadImageFunc(__VA_ARGS__);                                  \
  } else {                                                               \
    _dyld_register_func_for_add_image(__VA_ARGS__);                      \
  }
#else
#define REGISTER_FUNC(...) _dyld_register_func_for_add_image(__VA_ARGS__)
#endif

// WARNING: the callbacks are called from unsafe contexts (with the dyld and
// ObjC runtime locks held) and must be very careful in what they do. Locking
// must be arranged to avoid deadlocks (other code must never call out to dyld
// or ObjC holding a lock that gets taken in one of these callbacks) and the
// new/delete operators must not be called, in case a program supplies an
// overload which does not cooperate with these requirements.

void swift::initializeProtocolLookup() {
  REGISTER_FUNC(addImageCallback<TextSegment, ProtocolsSection,
                                 addImageProtocolsBlockCallbackUnsafe>);
}

void swift::initializeProtocolConformanceLookup() {
  REGISTER_FUNC(
      addImageCallback<TextSegment, ProtocolConformancesSection,
                       addImageProtocolConformanceBlockCallbackUnsafe>);
}
void swift::initializeTypeMetadataRecordLookup() {
  REGISTER_FUNC(
      addImageCallback<TextSegment, TypeMetadataRecordSection,
                       addImageTypeMetadataRecordBlockCallbackUnsafe>);
}

void swift::initializeDynamicReplacementLookup() {
  REGISTER_FUNC(
      addImageCallback2Sections<TextSegment, DynamicReplacementSection,
                                TextSegment, DynamicReplacementSomeSection,
                                addImageDynamicReplacementBlockCallback>);
}

void swift::initializeAccessibleFunctionsLookup() {
  REGISTER_FUNC(
      addImageCallback<TextSegment, AccessibleFunctionsSection,
                       addImageAccessibleFunctionsBlockCallbackUnsafe>);
}

#if SWIFT_STDLIB_HAS_DLADDR
int swift::lookupSymbol(const void *address, SymbolInfo *info) {
  Dl_info dlinfo;
  if (dladdr(address, &dlinfo) == 0) {
    return 0;
  }

  info->fileName = dlinfo.dli_fname;
  info->baseAddress = dlinfo.dli_fbase;
  info->symbolName.reset(dlinfo.dli_sname);
  info->symbolAddress = dlinfo.dli_saddr;
  return 1;
}
#endif

#endif // defined(__APPLE__) && defined(__MACH__) &&
       // !defined(SWIFT_RUNTIME_STATIC_IMAGE_INSPECTION)