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_INTERNAL_LINUX_H_
9 #define BASE_PROCESS_INTERNAL_LINUX_H_
10 
11 #include <stddef.h>
12 #include <stdint.h>
13 #include <unistd.h>
14 
15 #include "base/files/file_path.h"
16 
17 namespace base {
18 
19 class Time;
20 class TimeDelta;
21 
22 namespace internal {
23 
24 // "/proc"
25 extern const char kProcDir[];
26 
27 // "stat"
28 extern const char kStatFile[];
29 
30 // Returns a FilePath to "/proc/pid".
31 base::FilePath GetProcPidDir(pid_t pid);
32 
33 // Take a /proc directory entry named |d_name|, and if it is the directory for
34 // a process, convert it to a pid_t.
35 // Returns 0 on failure.
36 // e.g. /proc/self/ will return 0, whereas /proc/1234 will return 1234.
37 pid_t ProcDirSlotToPid(const char* d_name);
38 
39 // Reads /proc/<pid>/stat into |buffer|. Returns true if the file can be read
40 // and is non-empty.
41 bool ReadProcStats(pid_t pid, std::string* buffer);
42 
43 // Takes |stats_data| and populates |proc_stats| with the values split by
44 // spaces. Taking into account the 2nd field may, in itself, contain spaces.
45 // Returns true if successful.
46 bool ParseProcStats(const std::string& stats_data,
47                     std::vector<std::string>* proc_stats);
48 
49 // Fields from /proc/<pid>/stat, 0-based. See man 5 proc.
50 // If the ordering ever changes, carefully review functions that use these
51 // values.
52 enum ProcStatsFields {
53   VM_COMM           = 1,   // Filename of executable, without parentheses.
54   VM_STATE          = 2,   // Letter indicating the state of the process.
55   VM_PPID           = 3,   // PID of the parent.
56   VM_PGRP           = 4,   // Process group id.
57   VM_UTIME          = 13,  // Time scheduled in user mode in clock ticks.
58   VM_STIME          = 14,  // Time scheduled in kernel mode in clock ticks.
59   VM_NUMTHREADS     = 19,  // Number of threads.
60   VM_STARTTIME      = 21,  // The time the process started in clock ticks.
61   VM_VSIZE          = 22,  // Virtual memory size in bytes.
62   VM_RSS            = 23,  // Resident Set Size in pages.
63 };
64 
65 // Reads the |field_num|th field from |proc_stats|. Returns 0 on failure.
66 // This version does not handle the first 3 values, since the first value is
67 // simply |pid|, and the next two values are strings.
68 int64_t GetProcStatsFieldAsInt64(const std::vector<std::string>& proc_stats,
69                                  ProcStatsFields field_num);
70 
71 // Same as GetProcStatsFieldAsInt64(), but for size_t values.
72 size_t GetProcStatsFieldAsSizeT(const std::vector<std::string>& proc_stats,
73                                 ProcStatsFields field_num);
74 
75 // Convenience wrapper around GetProcStatsFieldAsInt64(), ParseProcStats() and
76 // ReadProcStats(). See GetProcStatsFieldAsInt64() for details.
77 int64_t ReadProcStatsAndGetFieldAsInt64(pid_t pid, ProcStatsFields field_num);
78 
79 // Same as ReadProcStatsAndGetFieldAsInt64() but for size_t values.
80 size_t ReadProcStatsAndGetFieldAsSizeT(pid_t pid,
81                                        ProcStatsFields field_num);
82 
83 // Returns the time that the OS started. Clock ticks are relative to this.
84 Time GetBootTime();
85 
86 // Converts Linux clock ticks to a wall time delta.
87 TimeDelta ClockTicksToTimeDelta(int clock_ticks);
88 
89 }  // namespace internal
90 }  // namespace base
91 
92 #endif  // BASE_PROCESS_INTERNAL_LINUX_H_
93