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// Copyright (c) 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// This file contains internal routines that are called by other files in
// base/process/.
#include <stddef.h>
#include <stdint.h>
#include <unistd.h>
#include "base/files/file_path.h"
namespace base {
class Time;
class TimeDelta;
namespace internal {
// "/proc"
extern const char kProcDir[];
// "stat"
extern const char kStatFile[];
// Returns a FilePath to "/proc/pid".
base::FilePath GetProcPidDir(pid_t pid);
// Take a /proc directory entry named |d_name|, and if it is the directory for
// a process, convert it to a pid_t.
// Returns 0 on failure.
// e.g. /proc/self/ will return 0, whereas /proc/1234 will return 1234.
pid_t ProcDirSlotToPid(const char* d_name);
// Reads /proc/<pid>/stat into |buffer|. Returns true if the file can be read
// and is non-empty.
bool ReadProcStats(pid_t pid, std::string* buffer);
// Takes |stats_data| and populates |proc_stats| with the values split by
// spaces. Taking into account the 2nd field may, in itself, contain spaces.
// Returns true if successful.
bool ParseProcStats(const std::string& stats_data,
std::vector<std::string>* proc_stats);
// Fields from /proc/<pid>/stat, 0-based. See man 5 proc.
// If the ordering ever changes, carefully review functions that use these
// values.
enum ProcStatsFields {
VM_COMM = 1, // Filename of executable, without parentheses.
VM_STATE = 2, // Letter indicating the state of the process.
VM_PPID = 3, // PID of the parent.
VM_PGRP = 4, // Process group id.
VM_MINFLT = 9, // Minor page fault count excluding children.
VM_MAJFLT = 11, // Major page fault count excluding children.
VM_UTIME = 13, // Time scheduled in user mode in clock ticks.
VM_STIME = 14, // Time scheduled in kernel mode in clock ticks.
VM_NUMTHREADS = 19, // Number of threads.
VM_STARTTIME = 21, // The time the process started in clock ticks.
VM_VSIZE = 22, // Virtual memory size in bytes.
VM_RSS = 23, // Resident Set Size in pages.
// Reads the |field_num|th field from |proc_stats|. Returns 0 on failure.
// This version does not handle the first 3 values, since the first value is
// simply |pid|, and the next two values are strings.
int64_t GetProcStatsFieldAsInt64(const std::vector<std::string>& proc_stats,
ProcStatsFields field_num);
// Same as GetProcStatsFieldAsInt64(), but for size_t values.
size_t GetProcStatsFieldAsSizeT(const std::vector<std::string>& proc_stats,
ProcStatsFields field_num);
// Convenience wrappers around GetProcStatsFieldAsInt64(), ParseProcStats() and
// ReadProcStats(). See GetProcStatsFieldAsInt64() for details.
int64_t ReadStatsFilendGetFieldAsInt64(const FilePath& stat_file,
ProcStatsFields field_num);
int64_t ReadProcStatsAndGetFieldAsInt64(pid_t pid, ProcStatsFields field_num);
int64_t ReadProcSelfStatsAndGetFieldAsInt64(ProcStatsFields field_num);
// Same as ReadProcStatsAndGetFieldAsInt64() but for size_t values.
size_t ReadProcStatsAndGetFieldAsSizeT(pid_t pid,
ProcStatsFields field_num);
// Returns the time that the OS started. Clock ticks are relative to this.
Time GetBootTime();
// Returns the amount of time spent in user space since boot across all CPUs.
TimeDelta GetUserCpuTimeSinceBoot();
// Converts Linux clock ticks to a wall time delta.
TimeDelta ClockTicksToTimeDelta(int clock_ticks);
} // namespace internal
} // namespace base