stack_copier_signal.cc | Explore in Territory

// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/profiler/stack_copier_signal.h"

#include <errno.h>
#include <linux/futex.h>
#include <signal.h>
#include <stdint.h>
#include <sys/ucontext.h>
#include <syscall.h>

#include <atomic>
#include <cstring>
#include <optional>

#include "base/memory/raw_ptr.h"
#include "base/memory/raw_ptr_exclusion.h"
#include "base/notreached.h"
#include "base/profiler/register_context.h"
#include "base/profiler/stack_buffer.h"
#include "base/profiler/suspendable_thread_delegate.h"
#include "base/time/time_override.h"
#include "base/trace_event/base_tracing.h"
#include "build/build_config.h"

namespace base {

namespace {

// Waitable event implementation with futex and without DCHECK(s), since signal
// handlers cannot allocate memory or use pthread api.
class AsyncSafeWaitableEvent { … };

// Scoped signal event that calls Signal on the AsyncSafeWaitableEvent at
// destructor.
class ScopedEventSignaller { … };

// Struct to store the arguments to the signal handler.
struct HandlerParams { … };

// Pointer to the parameters to be "passed" to the CopyStackSignalHandler() from
// the sampling thread to the sampled (stopped) thread. This value is set just
// before sending the signal to the thread and reset when the handler is done.
std::atomic<HandlerParams*> g_handler_params;

// CopyStackSignalHandler is invoked on the stopped thread and records the
// thread's stack and register context at the time the signal was received. This
// function may only call reentrant code.
void CopyStackSignalHandler(int n, siginfo_t* siginfo, void* sigcontext) { … }

// Sets the global handler params for the signal handler function.
class ScopedSetSignalHandlerParams { … };

class ScopedSigaction { … };

}  // namespace

StackCopierSignal::StackCopierSignal(
    std::unique_ptr<ThreadDelegate> thread_delegate)
    : … { … }

StackCopierSignal::~StackCopierSignal() = default;

bool StackCopierSignal::CopyStack(StackBuffer* stack_buffer,
                                  uintptr_t* stack_top,
                                  TimeTicks* timestamp,
                                  RegisterContext* thread_context,
                                  Delegate* delegate) { … }

std::vector<uintptr_t*> StackCopierSignal::GetRegistersToRewrite(
    RegisterContext* thread_context) { … }

}  // namespace base
chromium/base/profiler/stack_copier_signal.cc
