The Tor Browser: tools/profiler/AutoObjectMapper.cpp@6474c204b198 (annotated)

tools/profiler/AutoObjectMapper.cpp@6474c204b198 (annotated)

tools/profiler/AutoObjectMapper.cpp

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include <sys/mman.h>
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 #include "mozilla/Assertions.h"
 #include "mozilla/NullPtr.h"
 #include "PlatformMacros.h"
 #include "AutoObjectMapper.h"
 #if defined(SPS_OS_android) && !defined(MOZ_WIDGET_GONK)
 # include <dlfcn.h>
 # include "mozilla/Types.h"
   // FIXME move these out of mozglue/linker/ElfLoader.h into their
   // own header, so as to avoid conflicts arising from two definitions
   // of Array
   extern "C" {
     MFBT_API size_t
     __dl_get_mappable_length(void *handle);
     MFBT_API void *
     __dl_mmap(void *handle, void *addr, size_t length, off_t offset);
     MFBT_API void
     __dl_munmap(void *handle, void *addr, size_t length);
   }
   // The following are for get_installation_lib_dir()
 # include "nsString.h"
 # include "nsDirectoryServiceUtils.h"
 # include "nsDirectoryServiceDefs.h"
 #endif
 // A helper function for creating failure error messages in
 // AutoObjectMapper*::Map.
 static void
 failedToMessage(void(*aLog)(const char*),
                 const char* aHowFailed, std::string aFileName)
 {
   char buf[300];
   snprintf(buf, sizeof(buf), "AutoObjectMapper::Map: Failed to %s \'%s\'",
            aHowFailed, aFileName.c_str());
   buf[sizeof(buf)-1] = 0;
   aLog(buf);
 }
 AutoObjectMapperPOSIX::AutoObjectMapperPOSIX(void(*aLog)(const char*))
   : mImage(nullptr)
   , mSize(0)
   , mLog(aLog)
   , mIsMapped(false)
 {}
 AutoObjectMapperPOSIX::~AutoObjectMapperPOSIX() {
   if (!mIsMapped) {
     // There's nothing to do.
     MOZ_ASSERT(!mImage);
     MOZ_ASSERT(mSize == 0);
     return;
   }
   MOZ_ASSERT(mSize > 0);
   // The following assertion doesn't necessarily have to be true,
   // but we assume (reasonably enough) that no mmap facility would
   // be crazy enough to map anything at page zero.
   MOZ_ASSERT(mImage);
   munmap(mImage, mSize);
 }
 bool AutoObjectMapperPOSIX::Map(/*OUT*/void** start, /*OUT*/size_t* length,
                                 std::string fileName)
 {
   MOZ_ASSERT(!mIsMapped);
   int fd = open(fileName.c_str(), O_RDONLY);
   if (fd == -1) {
     failedToMessage(mLog, "open", fileName);
     return false;
   }
   struct stat st;
   int    err = fstat(fd, &st);
   size_t sz  = (err == 0) ? st.st_size : 0;
   if (err != 0 || sz == 0) {
     failedToMessage(mLog, "fstat", fileName);
     close(fd);
     return false;
   }
   void* image = mmap(nullptr, sz, PROT_READ, MAP_SHARED, fd, 0);
   if (image == MAP_FAILED) {
     failedToMessage(mLog, "mmap", fileName);
     close(fd);
     return false;
   }
   close(fd);
   mIsMapped = true;
   mImage = *start  = image;
   mSize  = *length = sz;
   return true;
 }
 #if defined(SPS_OS_android) && !defined(MOZ_WIDGET_GONK)
 // A helper function for AutoObjectMapperFaultyLib::Map.  Finds out
 // where the installation's lib directory is, since we'll have to look
 // in there to get hold of libmozglue.so.  Returned C string is heap
 // allocated and the caller must deallocate it.
 static char*
 get_installation_lib_dir()
 {
   nsCOMPtr<nsIProperties>
     directoryService(do_GetService(NS_DIRECTORY_SERVICE_CONTRACTID));
   if (!directoryService) {
     return nullptr;
   }
   nsCOMPtr<nsIFile> greDir;
   nsresult rv = directoryService->Get(NS_GRE_DIR, NS_GET_IID(nsIFile),
                                       getter_AddRefs(greDir));
   if (NS_FAILED(rv)) return nullptr;
   nsCString path;
   rv = greDir->GetNativePath(path);
   if (NS_FAILED(rv)) {
     return nullptr;
   }
   return strdup(path.get());
 }
 AutoObjectMapperFaultyLib::AutoObjectMapperFaultyLib(void(*aLog)(const char*))
   : AutoObjectMapperPOSIX(aLog)
   , mHdl(nullptr)
 {}
 AutoObjectMapperFaultyLib::~AutoObjectMapperFaultyLib() {
   if (mHdl) {
     // We've got an object mapped by faulty.lib.  Unmap it via faulty.lib.
     MOZ_ASSERT(mSize > 0);
     // Assert on the basis that no valid mapping would start at page zero.
     MOZ_ASSERT(mImage);
     __dl_munmap(mHdl, mImage, mSize);
     dlclose(mHdl);
     // Stop assertions in ~AutoObjectMapperPOSIX from failing.
     mImage = nullptr;
     mSize  = 0;
   }
   // At this point the parent class destructor, ~AutoObjectMapperPOSIX,
   // gets called.  If that has something mapped in the normal way, it
   // will unmap it in the normal way.  Unfortunately there's no
   // obvious way to enforce the requirement that the object is mapped
   // either by faulty.lib or by the parent class, but not by both.
 }
 bool AutoObjectMapperFaultyLib::Map(/*OUT*/void** start, /*OUT*/size_t* length,
                                     std::string fileName)
 {
   MOZ_ASSERT(!mHdl);
   if (fileName == "libmozglue.so") {
     // Do (2) in the comment above.
     char* libdir = get_installation_lib_dir();
     if (libdir) {
       fileName = std::string(libdir) + "/lib/" + fileName;
       free(libdir);
     }
     // Hand the problem off to the standard mapper.
     return AutoObjectMapperPOSIX::Map(start, length, fileName);
   } else {
     // Do cases (1) and (3) in the comment above.  We have to
     // grapple with faulty.lib directly.
     void* hdl = dlopen(fileName.c_str(), RTLD_GLOBAL | RTLD_LAZY);
     if (!hdl) {
       failedToMessage(mLog, "get handle for ELF file", fileName);
       return false;
     }
     size_t sz = __dl_get_mappable_length(hdl);
     if (sz == 0) {
       dlclose(hdl);
       failedToMessage(mLog, "get size for ELF file", fileName);
       return false;
     }
     void* image = __dl_mmap(hdl, nullptr, sz, 0);
     if (image == MAP_FAILED) {
       dlclose(hdl);
       failedToMessage(mLog, "mmap ELF file", fileName);
       return false;
     }
     mHdl   = hdl;
     mImage = *start  = image;
     mSize  = *length = sz;
     return true;
   }
 }
 #endif // defined(SPS_OS_android) && !defined(MOZ_WIDGET_GONK)

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tools/profiler/AutoObjectMapper.cpp@6474c204b198 (annotated)

tools/profiler/AutoObjectMapper.cpp