The Tor Browser: toolkit/crashreporter/google-breakpad/src/client/mac/handler/exception

toolkit/crashreporter/google-breakpad/src/client/mac/handler/exception_handler.cc@6474c204b198 (annotated)

toolkit/crashreporter/google-breakpad/src/client/mac/handler/exception_handler.cc

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.

 // Copyright (c) 2006, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 // copyright notice, this list of conditions and the following disclaimer
 // in the documentation and/or other materials provided with the
 // distribution.
 //     * Neither the name of Google Inc. nor the names of its
 // contributors may be used to endorse or promote products derived from
 // this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <mach/exc.h>
 #include <mach/mig.h>
 #include <pthread.h>
 #include <signal.h>
 #include <TargetConditionals.h>
 #include <map>
 #include "client/mac/handler/exception_handler.h"
 #include "client/mac/handler/minidump_generator.h"
 #include "common/mac/macho_utilities.h"
 #include "common/mac/scoped_task_suspend-inl.h"
 #include "google_breakpad/common/minidump_exception_mac.h"
 #ifndef __EXCEPTIONS
 // This file uses C++ try/catch (but shouldn't). Duplicate the macros from
 // <c++/4.2.1/exception_defines.h> allowing this file to work properly with
 // exceptions disabled even when other C++ libraries are used. #undef the try
 // and catch macros first in case libstdc++ is in use and has already provided
 // its own definitions.
 #undef try
 #define try       if (true)
 #undef catch
 #define catch(X)  if (false)
 #endif  // __EXCEPTIONS
 #ifndef USE_PROTECTED_ALLOCATIONS
 #if TARGET_OS_IPHONE
 #define USE_PROTECTED_ALLOCATIONS 1
 #else
 #define USE_PROTECTED_ALLOCATIONS 0
 #endif
 #endif
 // If USE_PROTECTED_ALLOCATIONS is activated then the
 // gBreakpadAllocator needs to be setup in other code
 // ahead of time.  Please see ProtectedMemoryAllocator.h
 // for more details.
 #if USE_PROTECTED_ALLOCATIONS
   #include "protected_memory_allocator.h"
   extern ProtectedMemoryAllocator *gBreakpadAllocator;
 #endif
 namespace google_breakpad {
 static union {
 #if USE_PROTECTED_ALLOCATIONS
   char protected_buffer[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
 #endif
   google_breakpad::ExceptionHandler *handler;
 } gProtectedData;
 using std::map;
 // These structures and techniques are illustrated in
 // Mac OS X Internals, Amit Singh, ch 9.7
 struct ExceptionMessage {
   mach_msg_header_t           header;
   mach_msg_body_t             body;
   mach_msg_port_descriptor_t  thread;
   mach_msg_port_descriptor_t  task;
   NDR_record_t                ndr;
   exception_type_t            exception;
   mach_msg_type_number_t      code_count;
   integer_t                   code[EXCEPTION_CODE_MAX];
   char                        padding[512];
 };
 struct ExceptionParameters {
   ExceptionParameters() : count(0) {}
   mach_msg_type_number_t count;
   exception_mask_t masks[EXC_TYPES_COUNT];
   mach_port_t ports[EXC_TYPES_COUNT];
   exception_behavior_t behaviors[EXC_TYPES_COUNT];
   thread_state_flavor_t flavors[EXC_TYPES_COUNT];
 };
 struct ExceptionReplyMessage {
   mach_msg_header_t  header;
   NDR_record_t       ndr;
   kern_return_t      return_code;
 };
 // Only catch these three exceptions.  The other ones are nebulously defined
 // and may result in treating a non-fatal exception as fatal.
 exception_mask_t s_exception_mask = EXC_MASK_BAD_ACCESS |
 EXC_MASK_BAD_INSTRUCTION | EXC_MASK_ARITHMETIC | EXC_MASK_BREAKPOINT;
 #if !TARGET_OS_IPHONE
 extern "C" {
   // Forward declarations for functions that need "C" style compilation
   boolean_t exc_server(mach_msg_header_t* request,
                        mach_msg_header_t* reply);
   // This symbol must be visible to dlsym() - see
   // http://code.google.com/p/google-breakpad/issues/detail?id=345 for details.
   kern_return_t catch_exception_raise(mach_port_t target_port,
                                       mach_port_t failed_thread,
                                       mach_port_t task,
                                       exception_type_t exception,
                                       exception_data_t code,
                                       mach_msg_type_number_t code_count)
       __attribute__((visibility("default")));
 }
 #endif
 kern_return_t ForwardException(mach_port_t task,
                                mach_port_t failed_thread,
                                exception_type_t exception,
                                exception_data_t code,
                                mach_msg_type_number_t code_count);
 #if TARGET_OS_IPHONE
 // Implementation is based on the implementation generated by mig.
 boolean_t breakpad_exc_server(mach_msg_header_t* InHeadP,
                               mach_msg_header_t* OutHeadP) {
   OutHeadP->msgh_bits =
       MACH_MSGH_BITS(MACH_MSGH_BITS_REMOTE(InHeadP->msgh_bits), 0);
   OutHeadP->msgh_remote_port = InHeadP->msgh_remote_port;
   /* Minimal size: routine() will update it if different */
   OutHeadP->msgh_size = (mach_msg_size_t)sizeof(mig_reply_error_t);
   OutHeadP->msgh_local_port = MACH_PORT_NULL;
   OutHeadP->msgh_id = InHeadP->msgh_id + 100;
   if (InHeadP->msgh_id != 2401) {
     ((mig_reply_error_t*)OutHeadP)->NDR = NDR_record;
     ((mig_reply_error_t*)OutHeadP)->RetCode = MIG_BAD_ID;
     return FALSE;
   }
 #ifdef  __MigPackStructs
 #pragma pack(4)
 #endif
   typedef struct {
     mach_msg_header_t Head;
     /* start of the kernel processed data */
     mach_msg_body_t msgh_body;
     mach_msg_port_descriptor_t thread;
     mach_msg_port_descriptor_t task;
     /* end of the kernel processed data */
     NDR_record_t NDR;
     exception_type_t exception;
     mach_msg_type_number_t codeCnt;
     integer_t code[2];
     mach_msg_trailer_t trailer;
   } Request;
   typedef struct {
     mach_msg_header_t Head;
     NDR_record_t NDR;
     kern_return_t RetCode;
   } Reply;
 #ifdef  __MigPackStructs
 #pragma pack()
 #endif
   Request* In0P = (Request*)InHeadP;
   Reply* OutP = (Reply*)OutHeadP;
   if (In0P->task.name != mach_task_self()) {
     return FALSE;
   }
   OutP->RetCode = ForwardException(In0P->task.name,
                                    In0P->thread.name,
                                    In0P->exception,
                                    In0P->code,
                                    In0P->codeCnt);
   OutP->NDR = NDR_record;
   return TRUE;
 }
 #else
 boolean_t breakpad_exc_server(mach_msg_header_t* request,
                               mach_msg_header_t* reply) {
   return exc_server(request, reply);
 }
 // Callback from exc_server()
 kern_return_t catch_exception_raise(mach_port_t port, mach_port_t failed_thread,
                                     mach_port_t task,
                                     exception_type_t exception,
                                     exception_data_t code,
                                     mach_msg_type_number_t code_count) {
   if (task != mach_task_self()) {
     return KERN_FAILURE;
   }
   return ForwardException(task, failed_thread, exception, code, code_count);
 }
 #endif
 ExceptionHandler::ExceptionHandler(const string &dump_path,
                                    FilterCallback filter,
                                    MinidumpCallback callback,
                                    void* callback_context,
                                    bool install_handler,
                                    const char* port_name)
     : dump_path_(),
       filter_(filter),
       callback_(callback),
       callback_context_(callback_context),
       directCallback_(NULL),
       handler_thread_(NULL),
       handler_port_(MACH_PORT_NULL),
       previous_(NULL),
       installed_exception_handler_(false),
       is_in_teardown_(false),
       last_minidump_write_result_(false),
       use_minidump_write_mutex_(false) {
   // This will update to the ID and C-string pointers
   set_dump_path(dump_path);
   MinidumpGenerator::GatherSystemInformation();
 #if !TARGET_OS_IPHONE
   if (port_name)
     crash_generation_client_.reset(new CrashGenerationClient(port_name));
 #endif
   Setup(install_handler);
 }
 // special constructor if we want to bypass minidump writing and
 // simply get a callback with the exception information
 ExceptionHandler::ExceptionHandler(DirectCallback callback,
                                    void* callback_context,
                                    bool install_handler)
     : dump_path_(),
       filter_(NULL),
       callback_(NULL),
       callback_context_(callback_context),
       directCallback_(callback),
       handler_thread_(NULL),
       handler_port_(MACH_PORT_NULL),
       previous_(NULL),
       installed_exception_handler_(false),
       is_in_teardown_(false),
       last_minidump_write_result_(false),
       use_minidump_write_mutex_(false) {
   MinidumpGenerator::GatherSystemInformation();
   Setup(install_handler);
 }
 ExceptionHandler::~ExceptionHandler() {
   Teardown();
 }
 bool ExceptionHandler::WriteMinidump(bool write_exception_stream) {
   // If we're currently writing, just return
   if (use_minidump_write_mutex_)
     return false;
   use_minidump_write_mutex_ = true;
   last_minidump_write_result_ = false;
   // Lock the mutex.  Since we just created it, this will return immediately.
   if (pthread_mutex_lock(&minidump_write_mutex_) == 0) {
     // Send an empty message to the handle port so that a minidump will
     // be written
     bool result = SendMessageToHandlerThread(write_exception_stream ?
                                              kWriteDumpWithExceptionMessage :
                                              kWriteDumpMessage);
     if (!result) {
       pthread_mutex_unlock(&minidump_write_mutex_);
       return false;
     }
     // Wait for the minidump writer to complete its writing.  It will unlock
     // the mutex when completed
     pthread_mutex_lock(&minidump_write_mutex_);
   }
   use_minidump_write_mutex_ = false;
   UpdateNextID();
   return last_minidump_write_result_;
 }
 // static
 bool ExceptionHandler::WriteMinidump(const string &dump_path,
                                      bool write_exception_stream,
                                      MinidumpCallback callback,
                                      void* callback_context) {
   ExceptionHandler handler(dump_path, NULL, callback, callback_context, false,
                            NULL);
   return handler.WriteMinidump(write_exception_stream);
 }
 // static
 bool ExceptionHandler::WriteMinidumpForChild(mach_port_t child,
                                              mach_port_t child_blamed_thread,
                                              const string &dump_path,
                                              MinidumpCallback callback,
                                              void* callback_context) {
   ScopedTaskSuspend suspend(child);
   MinidumpGenerator generator(child, MACH_PORT_NULL);
   string dump_id;
   string dump_filename = generator.UniqueNameInDirectory(dump_path, &dump_id);
   generator.SetExceptionInformation(EXC_BREAKPOINT,
 #if defined(__i386__) || defined(__x86_64__)
                                     EXC_I386_BPT,
 #elif defined(__ppc__) || defined(__ppc64__)
                                     EXC_PPC_BREAKPOINT,
 #elif defined(__arm__)
                                     EXC_ARM_BREAKPOINT,
 #else
 #error architecture not supported
 #endif
 ,
                                     child_blamed_thread);
   bool result = generator.Write(dump_filename.c_str());
   if (callback) {
     return callback(dump_path.c_str(), dump_id.c_str(),
                     callback_context, result);
   }
   return result;
 }
 bool ExceptionHandler::WriteMinidumpWithException(int exception_type,
                                                   int exception_code,
                                                   int exception_subcode,
                                                   ucontext_t* task_context,
                                                   mach_port_t thread_name,
                                                   bool exit_after_write,
                                                   bool report_current_thread) {
   bool result = false;
   if (directCallback_) {
     if (directCallback_(callback_context_,
                         exception_type,
                         exception_code,
                         exception_subcode,
                         thread_name) ) {
       if (exit_after_write)
         _exit(exception_type);
     }
 #if !TARGET_OS_IPHONE
   } else if (IsOutOfProcess()) {
     if (exception_type && exception_code) {
       // If this is a real exception, give the filter (if any) a chance to
       // decide if this should be sent.
       if (filter_ && !filter_(callback_context_))
         return false;
       result = crash_generation_client_->RequestDumpForException(
           exception_type,
           exception_code,
           exception_subcode,
           thread_name);
       if (result && exit_after_write) {
         _exit(exception_type);
       }
     }
 #endif
   } else {
     string minidump_id;
     // Putting the MinidumpGenerator in its own context will ensure that the
     // destructor is executed, closing the newly created minidump file.
     if (!dump_path_.empty()) {
       MinidumpGenerator md(mach_task_self(),
                            report_current_thread ? MACH_PORT_NULL :
                                                    mach_thread_self());
       md.SetTaskContext(task_context);
       if (exception_type && exception_code) {
         // If this is a real exception, give the filter (if any) a chance to
         // decide if this should be sent.
         if (filter_ && !filter_(callback_context_))
           return false;
         md.SetExceptionInformation(exception_type, exception_code,
                                    exception_subcode, thread_name);
       }
       result = md.Write(next_minidump_path_c_);
     }
     // Call user specified callback (if any)
     if (callback_) {
       // If the user callback returned true and we're handling an exception
       // (rather than just writing out the file), then we should exit without
       // forwarding the exception to the next handler.
       if (callback_(dump_path_c_, next_minidump_id_c_, callback_context_,
                     result)) {
         if (exit_after_write)
           _exit(exception_type);
       }
     }
   }
   return result;
 }
 kern_return_t ForwardException(mach_port_t task, mach_port_t failed_thread,
                                exception_type_t exception,
                                exception_data_t code,
                                mach_msg_type_number_t code_count) {
   // At this time, we should have called Uninstall() on the exception handler
   // so that the current exception ports are the ones that we should be
   // forwarding to.
   ExceptionParameters current;
   current.count = EXC_TYPES_COUNT;
   mach_port_t current_task = mach_task_self();
   task_get_exception_ports(current_task,
                            s_exception_mask,
                            current.masks,
                            &current.count,
                            current.ports,
                            current.behaviors,
                            current.flavors);
   // Find the first exception handler that matches the exception
   unsigned int found;
   for (found = 0; found < current.count; ++found) {
     if (current.masks[found] & (1 << exception)) {
       break;
     }
   }
   // Nothing to forward
   if (found == current.count) {
     fprintf(stderr, "** No previous ports for forwarding!! \n");
     exit(KERN_FAILURE);
   }
   mach_port_t target_port = current.ports[found];
   exception_behavior_t target_behavior = current.behaviors[found];
   kern_return_t result;
   switch (target_behavior) {
     case EXCEPTION_DEFAULT:
       result = exception_raise(target_port, failed_thread, task, exception,
                                code, code_count);
       break;
     default:
       fprintf(stderr, "** Unknown exception behavior: %d\n", target_behavior);
       result = KERN_FAILURE;
       break;
   }
   return result;
 }
 // static
 void* ExceptionHandler::WaitForMessage(void* exception_handler_class) {
   ExceptionHandler* self =
     reinterpret_cast<ExceptionHandler*>(exception_handler_class);
   ExceptionMessage receive;
   // Wait for the exception info
   while (1) {
     receive.header.msgh_local_port = self->handler_port_;
     receive.header.msgh_size = static_cast<mach_msg_size_t>(sizeof(receive));
     kern_return_t result = mach_msg(&(receive.header),
                                     MACH_RCV_MSG | MACH_RCV_LARGE, 0,
                                     receive.header.msgh_size,
                                     self->handler_port_,
                                     MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
     if (result == KERN_SUCCESS) {
       // Uninstall our handler so that we don't get in a loop if the process of
       // writing out a minidump causes an exception.  However, if the exception
       // was caused by a fork'd process, don't uninstall things
       // If the actual exception code is zero, then we're calling this handler
       // in a way that indicates that we want to either exit this thread or
       // generate a minidump
       //
       // While reporting, all threads (except this one) must be suspended
       // to avoid misleading stacks.  If appropriate they will be resumed
       // afterwards.
       if (!receive.exception) {
         // Don't touch self, since this message could have been sent
         // from its destructor.
         if (receive.header.msgh_id == kShutdownMessage)
           return NULL;
         self->SuspendThreads();
 #if USE_PROTECTED_ALLOCATIONS
         if (gBreakpadAllocator)
           gBreakpadAllocator->Unprotect();
 #endif
         mach_port_t thread = MACH_PORT_NULL;
         int exception_type = 0;
         int exception_code = 0;
         if (receive.header.msgh_id == kWriteDumpWithExceptionMessage) {
           thread = receive.thread.name;
           exception_type = EXC_BREAKPOINT;
 #if defined(__i386__) || defined(__x86_64__)
           exception_code = EXC_I386_BPT;
 #elif defined(__ppc__) || defined(__ppc64__)
           exception_code = EXC_PPC_BREAKPOINT;
 #elif defined(__arm__)
           exception_code = EXC_ARM_BREAKPOINT;
 #else
 #error architecture not supported
 #endif
         }
         // Write out the dump and save the result for later retrieval
         self->last_minidump_write_result_ =
           self->WriteMinidumpWithException(exception_type, exception_code,
 , NULL, thread,
                                            false, false);
 #if USE_PROTECTED_ALLOCATIONS
         if (gBreakpadAllocator)
           gBreakpadAllocator->Protect();
 #endif
         self->ResumeThreads();
         if (self->use_minidump_write_mutex_)
           pthread_mutex_unlock(&self->minidump_write_mutex_);
       } else {
         // When forking a child process with the exception handler installed,
         // if the child crashes, it will send the exception back to the parent
         // process.  The check for task == self_task() ensures that only
         // exceptions that occur in the parent process are caught and
         // processed.  If the exception was not caused by this task, we
         // still need to call into the exception server and have it return
         // KERN_FAILURE (see catch_exception_raise) in order for the kernel
         // to move onto the host exception handler for the child task
         if (receive.task.name == mach_task_self()) {
           self->SuspendThreads();
 #if USE_PROTECTED_ALLOCATIONS
         if (gBreakpadAllocator)
           gBreakpadAllocator->Unprotect();
 #endif
         int subcode = 0;
         if (receive.exception == EXC_BAD_ACCESS && receive.code_count > 1)
           subcode = receive.code[1];
         // Generate the minidump with the exception data.
         self->WriteMinidumpWithException(receive.exception, receive.code[0],
                                          subcode, NULL, receive.thread.name,
                                          true, false);
 #if USE_PROTECTED_ALLOCATIONS
         // This may have become protected again within
         // WriteMinidumpWithException, but it needs to be unprotected for
         // UninstallHandler.
         if (gBreakpadAllocator)
           gBreakpadAllocator->Unprotect();
 #endif
         self->UninstallHandler(true);
 #if USE_PROTECTED_ALLOCATIONS
         if (gBreakpadAllocator)
           gBreakpadAllocator->Protect();
 #endif
         }
         // Pass along the exception to the server, which will setup the
         // message and call catch_exception_raise() and put the return
         // code into the reply.
         ExceptionReplyMessage reply;
         if (!breakpad_exc_server(&receive.header, &reply.header))
           exit(1);
         // Send a reply and exit
         mach_msg(&(reply.header), MACH_SEND_MSG,
                  reply.header.msgh_size, 0, MACH_PORT_NULL,
                  MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
       }
     }
   }
   return NULL;
 }
 // static
 void ExceptionHandler::SignalHandler(int sig, siginfo_t* info, void* uc) {
 #if USE_PROTECTED_ALLOCATIONS
   if (gBreakpadAllocator)
     gBreakpadAllocator->Unprotect();
 #endif
   gProtectedData.handler->WriteMinidumpWithException(
       EXC_SOFTWARE,
       MD_EXCEPTION_CODE_MAC_ABORT,
 ,
       static_cast<ucontext_t*>(uc),
       mach_thread_self(),
       true,
       true);
 #if USE_PROTECTED_ALLOCATIONS
   if (gBreakpadAllocator)
     gBreakpadAllocator->Protect();
 #endif
 }
 bool ExceptionHandler::InstallHandler() {
   // If a handler is already installed, something is really wrong.
   if (gProtectedData.handler != NULL) {
     return false;
   }
   if (!IsOutOfProcess()) {
     struct sigaction sa;
     memset(&sa, 0, sizeof(sa));
     sigemptyset(&sa.sa_mask);
     sigaddset(&sa.sa_mask, SIGABRT);
     sa.sa_sigaction = ExceptionHandler::SignalHandler;
     sa.sa_flags = SA_SIGINFO;
     scoped_ptr<struct sigaction> old(new struct sigaction);
     if (sigaction(SIGABRT, &sa, old.get()) == -1) {
       return false;
     }
     old_handler_.swap(old);
     gProtectedData.handler = this;
 #if USE_PROTECTED_ALLOCATIONS
     assert(((size_t)(gProtectedData.protected_buffer) & PAGE_MASK) == 0);
     mprotect(gProtectedData.protected_buffer, PAGE_SIZE, PROT_READ);
 #endif
   }
   try {
 #if USE_PROTECTED_ALLOCATIONS
     previous_ = new (gBreakpadAllocator->Allocate(sizeof(ExceptionParameters)) )
       ExceptionParameters();
 #else
     previous_ = new ExceptionParameters();
 #endif
   }
   catch (std::bad_alloc) {
     return false;
   }
   // Save the current exception ports so that we can forward to them
   previous_->count = EXC_TYPES_COUNT;
   mach_port_t current_task = mach_task_self();
   kern_return_t result = task_get_exception_ports(current_task,
                                                   s_exception_mask,
                                                   previous_->masks,
                                                   &previous_->count,
                                                   previous_->ports,
                                                   previous_->behaviors,
                                                   previous_->flavors);
   // Setup the exception ports on this task
   if (result == KERN_SUCCESS)
     result = task_set_exception_ports(current_task, s_exception_mask,
                                       handler_port_, EXCEPTION_DEFAULT,
                                       THREAD_STATE_NONE);
   installed_exception_handler_ = (result == KERN_SUCCESS);
   return installed_exception_handler_;
 }
 bool ExceptionHandler::UninstallHandler(bool in_exception) {
   kern_return_t result = KERN_SUCCESS;
   if (old_handler_.get()) {
     sigaction(SIGABRT, old_handler_.get(), NULL);
 #if USE_PROTECTED_ALLOCATIONS
     mprotect(gProtectedData.protected_buffer, PAGE_SIZE,
         PROT_READ | PROT_WRITE);
 #endif
     old_handler_.reset();
     gProtectedData.handler = NULL;
   }
   if (installed_exception_handler_) {
     mach_port_t current_task = mach_task_self();
     // Restore the previous ports
     for (unsigned int i = 0; i < previous_->count; ++i) {
        result = task_set_exception_ports(current_task, previous_->masks[i],
                                         previous_->ports[i],
                                         previous_->behaviors[i],
                                         previous_->flavors[i]);
       if (result != KERN_SUCCESS)
         return false;
     }
     // this delete should NOT happen if an exception just occurred!
     if (!in_exception) {
 #if USE_PROTECTED_ALLOCATIONS
       previous_->~ExceptionParameters();
 #else
       delete previous_;
 #endif
     }
     previous_ = NULL;
     installed_exception_handler_ = false;
   }
   return result == KERN_SUCCESS;
 }
 bool ExceptionHandler::Setup(bool install_handler) {
   if (pthread_mutex_init(&minidump_write_mutex_, NULL))
     return false;
   // Create a receive right
   mach_port_t current_task = mach_task_self();
   kern_return_t result = mach_port_allocate(current_task,
                                             MACH_PORT_RIGHT_RECEIVE,
                                             &handler_port_);
   // Add send right
   if (result == KERN_SUCCESS)
     result = mach_port_insert_right(current_task, handler_port_, handler_port_,
                                     MACH_MSG_TYPE_MAKE_SEND);
   if (install_handler && result == KERN_SUCCESS)
     if (!InstallHandler())
       return false;
   if (result == KERN_SUCCESS) {
     // Install the handler in its own thread, detached as we won't be joining.
     pthread_attr_t attr;
     pthread_attr_init(&attr);
     pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
     int thread_create_result = pthread_create(&handler_thread_, &attr,
                                               &WaitForMessage, this);
     pthread_attr_destroy(&attr);
     result = thread_create_result ? KERN_FAILURE : KERN_SUCCESS;
   }
   return result == KERN_SUCCESS;
 }
 bool ExceptionHandler::Teardown() {
   kern_return_t result = KERN_SUCCESS;
   is_in_teardown_ = true;
   if (!UninstallHandler(false))
     return false;
   // Send an empty message so that the handler_thread exits
   if (SendMessageToHandlerThread(kShutdownMessage)) {
     mach_port_t current_task = mach_task_self();
     result = mach_port_deallocate(current_task, handler_port_);
     if (result != KERN_SUCCESS)
       return false;
   } else {
     return false;
   }
   handler_thread_ = NULL;
   handler_port_ = MACH_PORT_NULL;
   pthread_mutex_destroy(&minidump_write_mutex_);
   return result == KERN_SUCCESS;
 }
 bool ExceptionHandler::SendMessageToHandlerThread(
     HandlerThreadMessage message_id) {
   ExceptionMessage msg;
   memset(&msg, 0, sizeof(msg));
   msg.header.msgh_id = message_id;
   if (message_id == kWriteDumpMessage ||
       message_id == kWriteDumpWithExceptionMessage) {
     // Include this thread's port.
     msg.thread.name = mach_thread_self();
     msg.thread.disposition = MACH_MSG_TYPE_PORT_SEND;
     msg.thread.type = MACH_MSG_PORT_DESCRIPTOR;
   }
   msg.header.msgh_size = sizeof(msg) - sizeof(msg.padding);
   msg.header.msgh_remote_port = handler_port_;
   msg.header.msgh_bits = MACH_MSGH_BITS(MACH_MSG_TYPE_COPY_SEND,
                                           MACH_MSG_TYPE_MAKE_SEND_ONCE);
   kern_return_t result = mach_msg(&(msg.header),
                                   MACH_SEND_MSG | MACH_SEND_TIMEOUT,
                                   msg.header.msgh_size, 0, 0,
                                   MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
   return result == KERN_SUCCESS;
 }
 void ExceptionHandler::UpdateNextID() {
   next_minidump_path_ =
     (MinidumpGenerator::UniqueNameInDirectory(dump_path_, &next_minidump_id_));
   next_minidump_path_c_ = next_minidump_path_.c_str();
   next_minidump_id_c_ = next_minidump_id_.c_str();
 }
 bool ExceptionHandler::SuspendThreads() {
   thread_act_port_array_t   threads_for_task;
   mach_msg_type_number_t    thread_count;
   if (task_threads(mach_task_self(), &threads_for_task, &thread_count))
     return false;
   // suspend all of the threads except for this one
   for (unsigned int i = 0; i < thread_count; ++i) {
     if (threads_for_task[i] != mach_thread_self()) {
       if (thread_suspend(threads_for_task[i]))
         return false;
     }
   }
   return true;
 }
 bool ExceptionHandler::ResumeThreads() {
   thread_act_port_array_t   threads_for_task;
   mach_msg_type_number_t    thread_count;
   if (task_threads(mach_task_self(), &threads_for_task, &thread_count))
     return false;
   // resume all of the threads except for this one
   for (unsigned int i = 0; i < thread_count; ++i) {
     if (threads_for_task[i] != mach_thread_self()) {
       if (thread_resume(threads_for_task[i]))
         return false;
     }
   }
   return true;
 }
 }  // namespace google_breakpad

The Tor Browser / annotate

toolkit/crashreporter/google-breakpad/src/client/mac/handler/exception_handler.cc@6474c204b198 (annotated)

toolkit/crashreporter/google-breakpad/src/client/mac/handler/exception_handler.cc