[Mac] Do not unload base::NativeLibrary-ies if they contain ObjC segments.
Once an ObjC image is loaded into a process, the runtime will place unloadable
data into its caches. If the bundle is unloaded, then ObjC calls could result
in dereferencing memory in an unloaded module.
CFBundle and NSBundle explicitly say to not unload executable bundles
containing ObjC, but we were doing so anyways (oops!).
BUG=172319
TEST=Verify that fixupSelectorsInMethodList crash does not happen anymore.
Review URL: https://chromiumcodereview.appspot.com/12793004
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@188356 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/base/native_library_mac.mm b/base/native_library_mac.mm
index eec586b..4a094756 100644
--- a/base/native_library_mac.mm
+++ b/base/native_library_mac.mm
@@ -5,9 +5,11 @@
#include "base/native_library.h"
#include <dlfcn.h>
+#include <mach-o/getsect.h>
#include "base/file_util.h"
#include "base/files/file_path.h"
+#include "base/logging.h"
#include "base/mac/scoped_cftyperef.h"
#include "base/string_util.h"
#include "base/threading/thread_restrictions.h"
@@ -15,6 +17,30 @@
namespace base {
+static NativeLibraryObjCStatus GetObjCStatusForImage(
+ const void* function_pointer) {
+ Dl_info info;
+ if (!dladdr(function_pointer, &info))
+ return OBJC_UNKNOWN;
+
+ // See if the the image contains an "ObjC image info" segment. This method
+ // of testing is used in _CFBundleGrokObjcImageInfoFromFile in
+ // CF-744/CFBundle.c, around lines 2447-2474.
+ //
+ // In 32-bit images, ObjC can be recognized in __OBJC,__image_info, whereas
+ // in 64-bit, the data is in __DATA,__objc_imageinfo.
+#if __LP64__
+ const section_64* section = getsectbynamefromheader_64(
+ reinterpret_cast<const struct mach_header_64*>(info.dli_fbase),
+ SEG_DATA, "__objc_imageinfo");
+#else
+ const section* section = getsectbynamefromheader(
+ reinterpret_cast<const struct mach_header*>(info.dli_fbase),
+ SEG_OBJC, "__image_info");
+#endif
+ return section == NULL ? OBJC_NOT_PRESENT : OBJC_PRESENT;
+}
+
// static
NativeLibrary LoadNativeLibrary(const base::FilePath& library_path,
std::string* error) {
@@ -27,6 +53,7 @@
NativeLibrary native_lib = new NativeLibraryStruct();
native_lib->type = DYNAMIC_LIB;
native_lib->dylib = dylib;
+ native_lib->objc_status = OBJC_UNKNOWN;
return native_lib;
}
base::mac::ScopedCFTypeRef<CFURLRef> url(
@@ -45,17 +72,26 @@
native_lib->type = BUNDLE;
native_lib->bundle = bundle;
native_lib->bundle_resource_ref = CFBundleOpenBundleResourceMap(bundle);
+ native_lib->objc_status = OBJC_UNKNOWN;
return native_lib;
}
// static
void UnloadNativeLibrary(NativeLibrary library) {
- if (library->type == BUNDLE) {
- CFBundleCloseBundleResourceMap(library->bundle,
- library->bundle_resource_ref);
- CFRelease(library->bundle);
+ if (library->objc_status == OBJC_NOT_PRESENT) {
+ if (library->type == BUNDLE) {
+ CFBundleCloseBundleResourceMap(library->bundle,
+ library->bundle_resource_ref);
+ CFRelease(library->bundle);
+ } else {
+ dlclose(library->dylib);
+ }
} else {
- dlclose(library->dylib);
+ VLOG(2) << "Not unloading NativeLibrary because it may contain an ObjC "
+ "segment. library->objc_status = " << library->objc_status;
+ // Deliberately do not CFRelease the bundle or dlclose the dylib because
+ // doing so can corrupt the ObjC runtime method caches. See
+ // http://crbug.com/172319 for details.
}
delete library;
}
@@ -63,13 +99,25 @@
// static
void* GetFunctionPointerFromNativeLibrary(NativeLibrary library,
const char* name) {
+ void* function_pointer = NULL;
+
+ // Get the function pointer using the right API for the type.
if (library->type == BUNDLE) {
base::mac::ScopedCFTypeRef<CFStringRef> symbol_name(
CFStringCreateWithCString(kCFAllocatorDefault, name,
kCFStringEncodingUTF8));
- return CFBundleGetFunctionPointerForName(library->bundle, symbol_name);
+ function_pointer = CFBundleGetFunctionPointerForName(library->bundle,
+ symbol_name);
+ } else {
+ function_pointer = dlsym(library->dylib, name);
}
- return dlsym(library->dylib, name);
+
+ // If this library hasn't been tested for having ObjC, use the function
+ // pointer to look up the section information for the library.
+ if (function_pointer && library->objc_status == OBJC_UNKNOWN)
+ library->objc_status = GetObjCStatusForImage(function_pointer);
+
+ return function_pointer;
}
// static
