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1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 // This file contains internal routines that are called by other files in
6 // base/process/.
7 
8 #ifndef BASE_PROCESS_LINUX_INTERNAL_H_
9 #define BASE_PROCESS_LINUX_INTERNAL_H_
10 
11 #include <unistd.h>
12 
13 #include "base/files/file_path.h"
14 
15 namespace base {
16 
17 class Time;
18 class TimeDelta;
19 
20 namespace internal {
21 
22 // "/proc"
23 extern const char kProcDir[];
24 
25 // "stat"
26 extern const char kStatFile[];
27 
28 // Returns a FilePath to "/proc/pid".
29 base::FilePath GetProcPidDir(pid_t pid);
30 
31 // Take a /proc directory entry named |d_name|, and if it is the directory for
32 // a process, convert it to a pid_t.
33 // Returns 0 on failure.
34 // e.g. /proc/self/ will return 0, whereas /proc/1234 will return 1234.
35 pid_t ProcDirSlotToPid(const char* d_name);
36 
37 // Reads /proc/<pid>/stat into |buffer|. Returns true if the file can be read
38 // and is non-empty.
39 bool ReadProcStats(pid_t pid, std::string* buffer);
40 
41 // Takes |stats_data| and populates |proc_stats| with the values split by
42 // spaces. Taking into account the 2nd field may, in itself, contain spaces.
43 // Returns true if successful.
44 bool ParseProcStats(const std::string& stats_data,
45                     std::vector<std::string>* proc_stats);
46 
47 // Fields from /proc/<pid>/stat, 0-based. See man 5 proc.
48 // If the ordering ever changes, carefully review functions that use these
49 // values.
50 enum ProcStatsFields {
51   VM_COMM           = 1,   // Filename of executable, without parentheses.
52   VM_STATE          = 2,   // Letter indicating the state of the process.
53   VM_PPID           = 3,   // PID of the parent.
54   VM_PGRP           = 4,   // Process group id.
55   VM_UTIME          = 13,  // Time scheduled in user mode in clock ticks.
56   VM_STIME          = 14,  // Time scheduled in kernel mode in clock ticks.
57   VM_NUMTHREADS     = 19,  // Number of threads.
58   VM_STARTTIME      = 21,  // The time the process started in clock ticks.
59   VM_VSIZE          = 22,  // Virtual memory size in bytes.
60   VM_RSS            = 23,  // Resident Set Size in pages.
61 };
62 
63 // Reads the |field_num|th field from |proc_stats|. Returns 0 on failure.
64 // This version does not handle the first 3 values, since the first value is
65 // simply |pid|, and the next two values are strings.
66 int64 GetProcStatsFieldAsInt64(const std::vector<std::string>& proc_stats,
67                                ProcStatsFields field_num);
68 
69 // Same as GetProcStatsFieldAsInt64(), but for size_t values.
70 size_t GetProcStatsFieldAsSizeT(const std::vector<std::string>& proc_stats,
71                                 ProcStatsFields field_num);
72 
73 // Convenience wrapper around GetProcStatsFieldAsInt64(), ParseProcStats() and
74 // ReadProcStats(). See GetProcStatsFieldAsInt64() for details.
75 int64 ReadProcStatsAndGetFieldAsInt64(pid_t pid, ProcStatsFields field_num);
76 
77 // Same as ReadProcStatsAndGetFieldAsInt64() but for size_t values.
78 size_t ReadProcStatsAndGetFieldAsSizeT(pid_t pid,
79                                        ProcStatsFields field_num);
80 
81 // Returns the time that the OS started. Clock ticks are relative to this.
82 Time GetBootTime();
83 
84 // Converts Linux clock ticks to a wall time delta.
85 TimeDelta ClockTicksToTimeDelta(int clock_ticks);
86 
87 }  // namespace internal
88 }  // namespace base
89 
90 #endif  // BASE_PROCESS_LINUX_INTERNAL_H_
91