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/*
* Copyright (C) 2017 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef SRC_TRACED_PROBES_FTRACE_FTRACE_PROCFS_H_
#define SRC_TRACED_PROBES_FTRACE_FTRACE_PROCFS_H_
#include <memory>
#include <set>
#include <string>
#include "perfetto/ext/base/scoped_file.h"
namespace perfetto {
class FtraceProcfs {
public:
static std::unique_ptr<FtraceProcfs> Create(const std::string& root);
static int g_kmesg_fd;
explicit FtraceProcfs(const std::string& root);
virtual ~FtraceProcfs();
// Enable the event under with the given |group| and |name|.
bool EnableEvent(const std::string& group, const std::string& name);
// Disable the event under with the given |group| and |name|.
bool DisableEvent(const std::string& group, const std::string& name);
// Disable all events by writing to the global enable file.
bool DisableAllEvents();
// Read the format for event with the given |group| and |name|.
// virtual for testing.
virtual std::string ReadEventFormat(const std::string& group,
const std::string& name) const;
virtual std::string ReadPageHeaderFormat() const;
// Read the "/per_cpu/cpuXX/stats" file for the given |cpu|.
std::string ReadCpuStats(size_t cpu) const;
// Set ftrace buffer size in pages.
// This size is *per cpu* so for the total size you have to multiply
// by the number of CPUs.
bool SetCpuBufferSizeInPages(size_t pages);
// Returns the number of CPUs.
// This will match the number of tracing/per_cpu/cpuXX directories.
size_t virtual NumberOfCpus() const;
// Clears the trace buffers for all CPUs. Blocks until this is done.
void ClearTrace();
// Writes the string |str| as an event into the trace buffer.
bool WriteTraceMarker(const std::string& str);
// Enable tracing.
bool EnableTracing();
// Disables tracing, does not clear the buffer.
bool DisableTracing();
// Enables/disables tracing, does not clear the buffer.
bool SetTracingOn(bool enable);
// Returns true iff tracing is enabled.
// Necessarily racy: another program could enable/disable tracing at any
// point.
bool IsTracingEnabled();
// Set the clock. |clock_name| should be one of the names returned by
// AvailableClocks. Setting the clock clears the buffer.
bool SetClock(const std::string& clock_name);
// Get the currently set clock.
std::string GetClock();
// Get all the available clocks.
std::set<std::string> AvailableClocks();
// Open the raw pipe for |cpu|.
virtual base::ScopedFile OpenPipeForCpu(size_t cpu);
virtual const std::set<std::string> GetEventNamesForGroup(
const std::string& path) const;
protected:
// virtual and public for testing.
virtual bool WriteToFile(const std::string& path, const std::string& str);
virtual bool AppendToFile(const std::string& path, const std::string& str);
virtual bool ClearFile(const std::string& path);
virtual char ReadOneCharFromFile(const std::string& path);
virtual std::string ReadFileIntoString(const std::string& path) const;
private:
// Checks the trace file is present at the given root path.
static bool CheckRootPath(const std::string& root);
bool WriteNumberToFile(const std::string& path, size_t value);
const std::string root_;
};
} // namespace perfetto
#endif // SRC_TRACED_PROBES_FTRACE_FTRACE_PROCFS_H_
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