base/native_library_mac.mm

   1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/native_library.h"
   6
   7 #include <dlfcn.h>
   8 #include <mach-o/getsect.h>
   9
  10 #include "base/files/file_path.h"
  11 #include "base/files/file_util.h"
  12 #include "base/logging.h"
  13 #include "base/mac/scoped_cftyperef.h"
  14 #include "base/strings/strcat.h"
  15 #include "base/strings/string_piece.h"
  16 #include "base/strings/string_util.h"
  17 #include "base/strings/utf_string_conversions.h"
  18 #include "base/threading/thread_restrictions.h"
  19
  20 namespace base {
  21
  22 static NativeLibraryObjCStatus GetObjCStatusForImage(
  23     const void* function_pointer) {
  24   Dl_info info;
  25   if (!dladdr(function_pointer, &info))
  26     return OBJC_UNKNOWN;
  27
  28   // See if the image contains an "ObjC image info" segment. This method
  29   // of testing is used in _CFBundleGrokObjcImageInfoFromFile in
  30   // CF-744/CFBundle.c, around lines 2447-2474.
  31   //
  32   // In 64-bit images, ObjC can be recognized in __DATA,__objc_imageinfo.
  33   const section_64* section = getsectbynamefromheader_64(
  34       reinterpret_cast<const struct mach_header_64*>(info.dli_fbase), SEG_DATA,
  35       "__objc_imageinfo");
  36   if (section)
  37     return OBJC_PRESENT;
  38   // ....except when "SharedRegionEncodingV2" is on, it's in
  39   // __DATA_CONST,__objc_image_info (see https://crbug.com/1220459#c16)
  40   section = getsectbynamefromheader_64(
  41       reinterpret_cast<const struct mach_header_64*>(info.dli_fbase),
  42       "__DATA_CONST", "__objc_imageinfo");
  43   return section ? OBJC_PRESENT : OBJC_NOT_PRESENT;
  44 }
  45
  46 std::string NativeLibraryLoadError::ToString() const {
  47   return message;
  48 }
  49
  50 NativeLibrary LoadNativeLibraryWithOptions(const FilePath& library_path,
  51                                            const NativeLibraryOptions& options,
  52                                            NativeLibraryLoadError* error) {
  53   // dlopen() etc. open the file off disk.
  54   if (library_path.Extension() == "dylib" || !DirectoryExists(library_path)) {
  55     void* dylib = dlopen(library_path.value().c_str(), RTLD_LAZY);
  56     if (!dylib) {
  57       if (error)
  58         error->message = dlerror();
  59       return nullptr;
  60     }
  61     NativeLibrary native_lib = new NativeLibraryStruct();
  62     native_lib->type = DYNAMIC_LIB;
  63     native_lib->dylib = dylib;
  64     native_lib->objc_status = OBJC_UNKNOWN;
  65     return native_lib;
  66   }
  67   ScopedCFTypeRef<CFURLRef> url(CFURLCreateFromFileSystemRepresentation(
  68       kCFAllocatorDefault,
  69       (const UInt8*)library_path.value().c_str(),
  70       library_path.value().length(),
  71       true));
  72   if (!url)
  73     return nullptr;
  74   CFBundleRef bundle = CFBundleCreate(kCFAllocatorDefault, url.get());
  75   if (!bundle)
  76     return nullptr;
  77
  78   NativeLibrary native_lib = new NativeLibraryStruct();
  79   native_lib->type = BUNDLE;
  80   native_lib->bundle = bundle;
  81   native_lib->bundle_resource_ref = CFBundleOpenBundleResourceMap(bundle);
  82   native_lib->objc_status = OBJC_UNKNOWN;
  83   return native_lib;
  84 }
  85
  86 void UnloadNativeLibrary(NativeLibrary library) {
  87   if (library->objc_status == OBJC_NOT_PRESENT) {
  88     if (library->type == BUNDLE) {
  89       CFBundleCloseBundleResourceMap(library->bundle,
  90                                      library->bundle_resource_ref);
  91       CFRelease(library->bundle);
  92     } else {
  93       dlclose(library->dylib);
  94     }
  95   } else {
  96     VLOG(2) << "Not unloading NativeLibrary because it may contain an ObjC "
  97                "segment. library->objc_status = " << library->objc_status;
  98     // Deliberately do not CFRelease the bundle or dlclose the dylib because
  99     // doing so can corrupt the ObjC runtime method caches. See
 100     // http://crbug.com/172319 for details.
 101   }
 102   delete library;
 103 }
 104
 105 void* GetFunctionPointerFromNativeLibrary(NativeLibrary library,
 106                                           StringPiece name) {
 107   void* function_pointer = nullptr;
 108
 109   // Get the function pointer using the right API for the type.
 110   if (library->type == BUNDLE) {
 111     ScopedCFTypeRef<CFStringRef> symbol_name(CFStringCreateWithCString(
 112         kCFAllocatorDefault, name.data(), kCFStringEncodingUTF8));
 113     function_pointer = CFBundleGetFunctionPointerForName(library->bundle,
 114                                                          symbol_name);
 115   } else {
 116     function_pointer = dlsym(library->dylib, name.data());
 117   }
 118
 119   // If this library hasn't been tested for having ObjC, use the function
 120   // pointer to look up the section information for the library.
 121   if (function_pointer && library->objc_status == OBJC_UNKNOWN)
 122     library->objc_status = GetObjCStatusForImage(function_pointer);
 123
 124   return function_pointer;
 125 }
 126
 127 std::string GetNativeLibraryName(StringPiece name) {
 128   DCHECK(IsStringASCII(name));
 129   return StrCat({"lib", name, ".dylib"});
 130 }
 131
 132 std::string GetLoadableModuleName(StringPiece name) {
 133   DCHECK(IsStringASCII(name));
 134   return StrCat({name, ".so"});
 135 }
 136
 137 }  // namespace base