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/string_util.h"
  15 #include "base/strings/utf_string_conversions.h"
  16 #include "base/threading/thread_restrictions.h"
  17
  18 namespace base {
  19
  20 static NativeLibraryObjCStatus GetObjCStatusForImage(
  21     const void* function_pointer) {
  22   Dl_info info;
  23   if (!dladdr(function_pointer, &info))
  24     return OBJC_UNKNOWN;
  25
  26   // See if the the image contains an "ObjC image info" segment. This method
  27   // of testing is used in _CFBundleGrokObjcImageInfoFromFile in
  28   // CF-744/CFBundle.c, around lines 2447-2474.
  29   //
  30   // In 32-bit images, ObjC can be recognized in __OBJC,__image_info, whereas
  31   // in 64-bit, the data is in __DATA,__objc_imageinfo.
  32 #if __LP64__
  33   const section_64* section = getsectbynamefromheader_64(
  34       reinterpret_cast<const struct mach_header_64*>(info.dli_fbase),
  35       SEG_DATA, "__objc_imageinfo");
  36 #else
  37   const section* section = getsectbynamefromheader(
  38       reinterpret_cast<const struct mach_header*>(info.dli_fbase),
  39       SEG_OBJC, "__image_info");
  40 #endif
  41   return section == NULL ? OBJC_NOT_PRESENT : OBJC_PRESENT;
  42 }
  43
  44 std::string NativeLibraryLoadError::ToString() const {
  45   return message;
  46 }
  47
  48 // static
  49 NativeLibrary LoadNativeLibrary(const base::FilePath& library_path,
  50                                 NativeLibraryLoadError* error) {
  51   // dlopen() etc. open the file off disk.
  52   if (library_path.Extension() == "dylib" || !DirectoryExists(library_path)) {
  53     void* dylib = dlopen(library_path.value().c_str(), RTLD_LAZY);
  54     if (!dylib) {
  55       error->message = dlerror();
  56       return NULL;
  57     }
  58     NativeLibrary native_lib = new NativeLibraryStruct();
  59     native_lib->type = DYNAMIC_LIB;
  60     native_lib->dylib = dylib;
  61     native_lib->objc_status = OBJC_UNKNOWN;
  62     return native_lib;
  63   }
  64   base::ScopedCFTypeRef<CFURLRef> url(CFURLCreateFromFileSystemRepresentation(
  65       kCFAllocatorDefault,
  66       (const UInt8*)library_path.value().c_str(),
  67       library_path.value().length(),
  68       true));
  69   if (!url)
  70     return NULL;
  71   CFBundleRef bundle = CFBundleCreate(kCFAllocatorDefault, url.get());
  72   if (!bundle)
  73     return NULL;
  74
  75   NativeLibrary native_lib = new NativeLibraryStruct();
  76   native_lib->type = BUNDLE;
  77   native_lib->bundle = bundle;
  78   native_lib->bundle_resource_ref = CFBundleOpenBundleResourceMap(bundle);
  79   native_lib->objc_status = OBJC_UNKNOWN;
  80   return native_lib;
  81 }
  82
  83 // static
  84 void UnloadNativeLibrary(NativeLibrary library) {
  85   if (library->objc_status == OBJC_NOT_PRESENT) {
  86     if (library->type == BUNDLE) {
  87       CFBundleCloseBundleResourceMap(library->bundle,
  88                                      library->bundle_resource_ref);
  89       CFRelease(library->bundle);
  90     } else {
  91       dlclose(library->dylib);
  92     }
  93   } else {
  94     VLOG(2) << "Not unloading NativeLibrary because it may contain an ObjC "
  95                "segment. library->objc_status = " << library->objc_status;
  96     // Deliberately do not CFRelease the bundle or dlclose the dylib because
  97     // doing so can corrupt the ObjC runtime method caches. See
  98     // http://crbug.com/172319 for details.
  99   }
 100   delete library;
 101 }
 102
 103 // static
 104 void* GetFunctionPointerFromNativeLibrary(NativeLibrary library,
 105                                           const char* name) {
 106   void* function_pointer = NULL;
 107
 108   // Get the function pointer using the right API for the type.
 109   if (library->type == BUNDLE) {
 110     base::ScopedCFTypeRef<CFStringRef> symbol_name(CFStringCreateWithCString(
 111         kCFAllocatorDefault, name, kCFStringEncodingUTF8));
 112     function_pointer = CFBundleGetFunctionPointerForName(library->bundle,
 113                                                          symbol_name);
 114   } else {
 115     function_pointer = dlsym(library->dylib, name);
 116   }
 117
 118   // If this library hasn't been tested for having ObjC, use the function
 119   // pointer to look up the section information for the library.
 120   if (function_pointer && library->objc_status == OBJC_UNKNOWN)
 121     library->objc_status = GetObjCStatusForImage(function_pointer);
 122
 123   return function_pointer;
 124 }
 125
 126 // static
 127 string16 GetNativeLibraryName(const string16& name) {
 128   return name + ASCIIToUTF16(".dylib");
 129 }
 130
 131 }  // namespace base