492 lines
19 KiB
C++
492 lines
19 KiB
C++
// Copyright 2020 The Crashpad Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "client/crashpad_client.h"
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#include <signal.h>
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#include <unistd.h>
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#include <atomic>
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#include <ios>
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#include <iterator>
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#include "base/logging.h"
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#include "base/mac/mach_logging.h"
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#include "base/mac/scoped_mach_port.h"
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#include "client/ios_handler/exception_processor.h"
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#include "client/ios_handler/in_process_handler.h"
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#include "util/ios/raw_logging.h"
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#include "util/mach/exc_server_variants.h"
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#include "util/mach/exception_ports.h"
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#include "util/mach/mach_extensions.h"
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#include "util/mach/mach_message.h"
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#include "util/mach/mach_message_server.h"
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#include "util/misc/initialization_state_dcheck.h"
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#include "util/posix/signals.h"
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#include "util/thread/thread.h"
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namespace {
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bool IsBeingDebugged() {
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kinfo_proc kern_proc_info;
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int mib[] = {CTL_KERN, KERN_PROC, KERN_PROC_PID, getpid()};
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size_t len = sizeof(kern_proc_info);
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if (sysctl(mib, std::size(mib), &kern_proc_info, &len, nullptr, 0) == 0)
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return kern_proc_info.kp_proc.p_flag & P_TRACED;
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return false;
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}
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} // namespace
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namespace crashpad {
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namespace {
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// A base class for signal handler and Mach exception server.
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class CrashHandler : public Thread,
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public UniversalMachExcServer::Interface,
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public ObjcExceptionDelegate {
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public:
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CrashHandler(const CrashHandler&) = delete;
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CrashHandler& operator=(const CrashHandler&) = delete;
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static CrashHandler* Get() {
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if (!instance_)
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instance_ = new CrashHandler();
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return instance_;
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}
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static void ResetForTesting() {
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delete instance_;
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instance_ = nullptr;
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}
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bool Initialize(
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const base::FilePath& database,
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const std::string& url,
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const std::map<std::string, std::string>& annotations,
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internal::InProcessHandler::ProcessPendingReportsObservationCallback
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callback) {
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INITIALIZATION_STATE_SET_INITIALIZING(initialized_);
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if (!in_process_handler_.Initialize(database, url, annotations, callback) ||
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!InstallMachExceptionHandler() ||
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// xnu turns hardware faults into Mach exceptions, so the only signal
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// left to register is SIGABRT, which never starts off as a hardware
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// fault. Installing a handler for other signals would lead to
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// recording exceptions twice. As a consequence, Crashpad will not
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// generate intermediate dumps for anything manually calling
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// raise(SIG*). In practice, this doesn’t actually happen for crash
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// signals that originate as hardware faults.
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!Signals::InstallHandler(
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SIGABRT, CatchAndReraiseSignal, 0, &old_action_)) {
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LOG(ERROR) << "Unable to initialize Crashpad.";
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return false;
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}
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// For applications that haven't ignored or set a handler for SIGPIPE:
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// It’s OK for an application to set its own SIGPIPE handler (including
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// SIG_IGN) before initializing Crashpad, because Crashpad will discover the
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// existing handler and not install its own.
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// It’s OK for Crashpad to install its own SIGPIPE handler and for the
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// application to subsequently install its own (including SIG_IGN)
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// afterwards, because its handler will replace Crashpad’s.
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// This is useful to cover the default situation where nobody installs a
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// SIGPIPE handler and the disposition is at SIG_DFL, because SIGPIPE is a
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// “kill” signal (bsd/sys/signalvar.h sigprop). In that case, without
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// Crashpad, SIGPIPE results in a silent and unreported kill (and not even
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// ReportCrash will record it), but developers probably want to be alerted
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// to the conditon.
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struct sigaction sa;
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if (sigaction(SIGPIPE, nullptr, &sa) == 0 && sa.sa_handler == SIG_DFL) {
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Signals::InstallHandler(
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SIGPIPE, CatchAndReraiseSignalDefaultAction, 0, nullptr);
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}
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InstallObjcExceptionPreprocessor(this);
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INITIALIZATION_STATE_SET_VALID(initialized_);
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return true;
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}
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void ProcessIntermediateDumps(
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const std::map<std::string, std::string>& annotations) {
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in_process_handler_.ProcessIntermediateDumps(annotations);
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}
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void ProcessIntermediateDump(
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const base::FilePath& file,
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const std::map<std::string, std::string>& annotations) {
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in_process_handler_.ProcessIntermediateDump(file, annotations);
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}
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void DumpWithoutCrash(NativeCPUContext* context, bool process_dump) {
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INITIALIZATION_STATE_DCHECK_VALID(initialized_);
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base::FilePath path;
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if (!in_process_handler_.DumpExceptionFromSimulatedMachException(
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context, kMachExceptionSimulated, &path)) {
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return;
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}
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if (process_dump) {
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in_process_handler_.ProcessIntermediateDump(path);
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}
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}
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void DumpWithoutCrashAtPath(NativeCPUContext* context,
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const base::FilePath& path) {
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in_process_handler_.DumpExceptionFromSimulatedMachExceptionAtPath(
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context, kMachExceptionSimulated, path);
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}
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void StartProcessingPendingReports(UploadBehavior upload_behavior) {
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INITIALIZATION_STATE_DCHECK_VALID(initialized_);
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in_process_handler_.StartProcessingPendingReports(upload_behavior);
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}
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void SetMachExceptionCallbackForTesting(void (*callback)()) {
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in_process_handler_.SetMachExceptionCallbackForTesting(callback);
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}
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uint64_t GetThreadIdForTesting() { return Thread::GetThreadIdForTesting(); }
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private:
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CrashHandler() = default;
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~CrashHandler() {
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UninstallObjcExceptionPreprocessor();
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Signals::InstallDefaultHandler(SIGABRT);
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UninstallMachExceptionHandler();
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}
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bool InstallMachExceptionHandler() {
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exception_port_.reset(NewMachPort(MACH_PORT_RIGHT_RECEIVE));
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if (!exception_port_.is_valid()) {
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return false;
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}
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kern_return_t kr = mach_port_insert_right(mach_task_self(),
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exception_port_.get(),
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exception_port_.get(),
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MACH_MSG_TYPE_MAKE_SEND);
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if (kr != KERN_SUCCESS) {
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MACH_LOG(ERROR, kr) << "mach_port_insert_right";
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return false;
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}
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// TODO: Use SwapExceptionPort instead and put back EXC_MASK_BREAKPOINT.
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// Until then, remove |EXC_MASK_BREAKPOINT| while attached to a debugger.
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exception_mask_t mask =
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ExcMaskAll() &
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~(EXC_MASK_EMULATION | EXC_MASK_SOFTWARE | EXC_MASK_RPC_ALERT |
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EXC_MASK_GUARD | (IsBeingDebugged() ? EXC_MASK_BREAKPOINT : 0));
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ExceptionPorts exception_ports(ExceptionPorts::kTargetTypeTask, TASK_NULL);
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if (!exception_ports.GetExceptionPorts(mask, &original_handlers_) ||
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!exception_ports.SetExceptionPort(
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mask,
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exception_port_.get(),
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EXCEPTION_STATE_IDENTITY | MACH_EXCEPTION_CODES,
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MACHINE_THREAD_STATE)) {
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return false;
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}
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mach_handler_running_ = true;
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Start();
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return true;
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}
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void UninstallMachExceptionHandler() {
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mach_handler_running_ = false;
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exception_port_.reset();
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Join();
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}
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// Thread:
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void ThreadMain() override {
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UniversalMachExcServer universal_mach_exc_server(this);
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while (mach_handler_running_) {
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mach_msg_return_t mr =
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MachMessageServer::Run(&universal_mach_exc_server,
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exception_port_.get(),
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MACH_MSG_OPTION_NONE,
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MachMessageServer::kPersistent,
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MachMessageServer::kReceiveLargeIgnore,
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kMachMessageTimeoutWaitIndefinitely);
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MACH_CHECK(
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mach_handler_running_
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? mr == MACH_SEND_INVALID_DEST // This shouldn't happen for
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// exception messages that come
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// from the kernel itself, but if
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// something else in-process sends
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// exception messages and breaks,
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// handle that case.
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: (mr == MACH_RCV_PORT_CHANGED || // Port was closed while the
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// thread was listening.
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mr == MACH_RCV_INVALID_NAME), // Port was closed before the
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// thread started listening.
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mr)
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<< "MachMessageServer::Run";
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}
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}
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// UniversalMachExcServer::Interface:
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kern_return_t CatchMachException(exception_behavior_t behavior,
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exception_handler_t exception_port,
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thread_t thread,
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task_t task,
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exception_type_t exception,
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const mach_exception_data_type_t* code,
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mach_msg_type_number_t code_count,
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thread_state_flavor_t* flavor,
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ConstThreadState old_state,
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mach_msg_type_number_t old_state_count,
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thread_state_t new_state,
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mach_msg_type_number_t* new_state_count,
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const mach_msg_trailer_t* trailer,
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bool* destroy_complex_request) override {
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*destroy_complex_request = true;
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// TODO(justincohen): Forward exceptions to original_handlers_ with
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// UniversalExceptionRaise.
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// iOS shouldn't have any child processes, but just in case, those will
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// inherit the task exception ports, and this process isn’t prepared to
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// handle them
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if (task != mach_task_self()) {
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CRASHPAD_RAW_LOG("MachException task != mach_task_self()");
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return KERN_FAILURE;
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}
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HandleMachException(behavior,
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thread,
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exception,
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code,
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code_count,
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*flavor,
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old_state,
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old_state_count);
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// Respond with KERN_FAILURE so the system will continue to handle this
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// exception. xnu will turn this Mach exception into a signal and take the
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// default action to terminate the process. However, if sigprocmask is
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// called before this Mach exception returns (such as by another thread
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// calling abort, see: Libc-1506.40.4/stdlib/FreeBSD/abort.c), the Mach
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// exception will be converted into a signal but delivery will be blocked.
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// Since concurrent exceptions lead to the losing thread sleeping
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// indefinitely, if the abort thread never returns, the thread that
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// triggered this Mach exception will repeatedly trap and the process will
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// never terminate. If the abort thread didn’t have a user-space signal
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// handler that slept forever, the abort would terminate the process even if
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// all other signals had been blocked. Instead, unblock all signals
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// corresponding to all Mach exceptions Crashpad is registered for before
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// returning KERN_FAILURE. There is still racy behavior possible with this
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// call to sigprocmask, but the repeated calls to CatchMachException here
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// will eventually lead to termination.
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sigset_t unblock_set;
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sigemptyset(&unblock_set);
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sigaddset(&unblock_set, SIGILL); // EXC_BAD_INSTRUCTION
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sigaddset(&unblock_set, SIGTRAP); // EXC_BREAKPOINT
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sigaddset(&unblock_set, SIGFPE); // EXC_ARITHMETIC
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sigaddset(&unblock_set, SIGBUS); // EXC_BAD_ACCESS
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sigaddset(&unblock_set, SIGSEGV); // EXC_BAD_ACCESS
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if (sigprocmask(SIG_UNBLOCK, &unblock_set, nullptr) != 0) {
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CRASHPAD_RAW_LOG("sigprocmask");
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}
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return KERN_FAILURE;
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}
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void HandleMachException(exception_behavior_t behavior,
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thread_t thread,
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exception_type_t exception,
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const mach_exception_data_type_t* code,
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mach_msg_type_number_t code_count,
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thread_state_flavor_t flavor,
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ConstThreadState old_state,
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mach_msg_type_number_t old_state_count) {
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in_process_handler_.DumpExceptionFromMachException(behavior,
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thread,
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exception,
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code,
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code_count,
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flavor,
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old_state,
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old_state_count);
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}
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void HandleUncaughtNSException(const uint64_t* frames,
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const size_t num_frames) override {
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in_process_handler_.DumpExceptionFromNSExceptionWithFrames(frames,
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num_frames);
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// After uncaught exceptions are reported, the system immediately triggers a
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// call to std::terminate()/abort(). Remove the abort handler so a second
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// dump isn't generated.
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CHECK(Signals::InstallDefaultHandler(SIGABRT));
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}
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void HandleUncaughtNSExceptionWithContext(
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NativeCPUContext* context) override {
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base::FilePath path;
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in_process_handler_.DumpExceptionFromSimulatedMachException(
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context, kMachExceptionFromNSException, &path);
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// After uncaught exceptions are reported, the system immediately triggers a
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// call to std::terminate()/abort(). Remove the abort handler so a second
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// dump isn't generated.
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CHECK(Signals::InstallDefaultHandler(SIGABRT));
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}
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void HandleUncaughtNSExceptionWithContextAtPath(
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NativeCPUContext* context,
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const base::FilePath& path) override {
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in_process_handler_.DumpExceptionFromSimulatedMachExceptionAtPath(
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context, kMachExceptionFromNSException, path);
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}
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bool MoveIntermediateDumpAtPathToPending(
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const base::FilePath& path) override {
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if (in_process_handler_.MoveIntermediateDumpAtPathToPending(path)) {
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// After uncaught exceptions are reported, the system immediately triggers
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// a call to std::terminate()/abort(). Remove the abort handler so a
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// second dump isn't generated.
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CHECK(Signals::InstallDefaultHandler(SIGABRT));
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return true;
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}
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return false;
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}
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// The signal handler installed at OS-level.
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static void CatchAndReraiseSignal(int signo,
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siginfo_t* siginfo,
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void* context) {
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Get()->HandleAndReraiseSignal(signo,
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siginfo,
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reinterpret_cast<ucontext_t*>(context),
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&(Get()->old_action_));
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}
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static void CatchAndReraiseSignalDefaultAction(int signo,
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siginfo_t* siginfo,
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void* context) {
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Get()->HandleAndReraiseSignal(
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signo, siginfo, reinterpret_cast<ucontext_t*>(context), nullptr);
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}
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void HandleAndReraiseSignal(int signo,
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siginfo_t* siginfo,
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ucontext_t* context,
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struct sigaction* old_action) {
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in_process_handler_.DumpExceptionFromSignal(siginfo, context);
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// Always call system handler.
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Signals::RestoreHandlerAndReraiseSignalOnReturn(siginfo, old_action);
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}
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base::mac::ScopedMachReceiveRight exception_port_;
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ExceptionPorts::ExceptionHandlerVector original_handlers_;
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struct sigaction old_action_ = {};
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internal::InProcessHandler in_process_handler_;
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static CrashHandler* instance_;
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std::atomic<bool> mach_handler_running_ = false;
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InitializationStateDcheck initialized_;
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};
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CrashHandler* CrashHandler::instance_ = nullptr;
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} // namespace
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CrashpadClient::CrashpadClient() {}
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CrashpadClient::~CrashpadClient() {}
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// static
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bool CrashpadClient::StartCrashpadInProcessHandler(
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const base::FilePath& database,
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const std::string& url,
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const std::map<std::string, std::string>& annotations,
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ProcessPendingReportsObservationCallback callback) {
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CrashHandler* crash_handler = CrashHandler::Get();
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DCHECK(crash_handler);
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return crash_handler->Initialize(database, url, annotations, callback);
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}
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// static
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void CrashpadClient::ProcessIntermediateDumps(
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const std::map<std::string, std::string>& annotations) {
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CrashHandler* crash_handler = CrashHandler::Get();
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DCHECK(crash_handler);
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crash_handler->ProcessIntermediateDumps(annotations);
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}
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// static
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void CrashpadClient::ProcessIntermediateDump(
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const base::FilePath& file,
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const std::map<std::string, std::string>& annotations) {
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CrashHandler* crash_handler = CrashHandler::Get();
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DCHECK(crash_handler);
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crash_handler->ProcessIntermediateDump(file, annotations);
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}
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// static
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void CrashpadClient::StartProcessingPendingReports(
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UploadBehavior upload_behavior) {
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CrashHandler* crash_handler = CrashHandler::Get();
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DCHECK(crash_handler);
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crash_handler->StartProcessingPendingReports(upload_behavior);
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}
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// static
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void CrashpadClient::DumpWithoutCrash(NativeCPUContext* context) {
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CrashHandler* crash_handler = CrashHandler::Get();
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DCHECK(crash_handler);
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crash_handler->DumpWithoutCrash(context, /*process_dump=*/true);
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}
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// static
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void CrashpadClient::DumpWithoutCrashAndDeferProcessing(
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NativeCPUContext* context) {
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CrashHandler* crash_handler = CrashHandler::Get();
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DCHECK(crash_handler);
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crash_handler->DumpWithoutCrash(context, /*process_dump=*/false);
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}
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// static
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void CrashpadClient::DumpWithoutCrashAndDeferProcessingAtPath(
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NativeCPUContext* context,
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const base::FilePath path) {
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CrashHandler* crash_handler = CrashHandler::Get();
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DCHECK(crash_handler);
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crash_handler->DumpWithoutCrashAtPath(context, path);
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}
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void CrashpadClient::ResetForTesting() {
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CrashHandler* crash_handler = CrashHandler::Get();
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DCHECK(crash_handler);
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crash_handler->ResetForTesting();
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}
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void CrashpadClient::SetMachExceptionCallbackForTesting(void (*callback)()) {
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CrashHandler* crash_handler = CrashHandler::Get();
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DCHECK(crash_handler);
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crash_handler->SetMachExceptionCallbackForTesting(callback);
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}
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uint64_t CrashpadClient::GetThreadIdForTesting() {
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CrashHandler* crash_handler = CrashHandler::Get();
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DCHECK(crash_handler);
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return crash_handler->GetThreadIdForTesting();
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}
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} // namespace crashpad
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