1 // Copyright 2013 The Chromium Authors
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 #include <string>
15 #include <vector>
16
17 #include "base/files/dir_reader_posix.h"
18 #include "base/files/file_path.h"
19 #include "base/process/process_handle.h"
20 #include "base/strings/string_number_conversions.h"
21 #include "base/threading/platform_thread.h"
22
23 namespace base {
24
25 class Time;
26 class TimeDelta;
27
28 namespace internal {
29
30 // "/proc"
31 extern const char kProcDir[];
32
33 // "stat"
34 extern const char kStatFile[];
35
36 // Returns a FilePath to "/proc/pid".
37 base::FilePath GetProcPidDir(pid_t pid);
38
39 // Reads a file from /proc into a string. This is allowed on any thread as
40 // reading from /proc does not hit the disk. Returns true if the file can be
41 // read and is non-empty.
42 bool ReadProcFile(const FilePath& file, std::string* buffer);
43
44 // Take a /proc directory entry named |d_name|, and if it is the directory for
45 // a process, convert it to a pid_t.
46 // Returns 0 on failure.
47 // e.g. /proc/self/ will return 0, whereas /proc/1234 will return 1234.
48 pid_t ProcDirSlotToPid(const char* d_name);
49
50 // Reads /proc/<pid>/stat into |buffer|. Returns true if the file can be read
51 // and is non-empty.
52 bool ReadProcStats(pid_t pid, std::string* buffer);
53
54 // Takes |stats_data| and populates |proc_stats| with the values split by
55 // spaces. Taking into account the 2nd field may, in itself, contain spaces.
56 // Returns true if successful.
57 bool ParseProcStats(const std::string& stats_data,
58 std::vector<std::string>* proc_stats);
59
60 // Fields from /proc/<pid>/stat, 0-based. See man 5 proc.
61 // If the ordering ever changes, carefully review functions that use these
62 // values.
63 enum ProcStatsFields {
64 VM_COMM = 1, // Filename of executable, without parentheses.
65 VM_STATE = 2, // Letter indicating the state of the process.
66 VM_PPID = 3, // PID of the parent.
67 VM_PGRP = 4, // Process group id.
68 VM_MINFLT = 9, // Minor page fault count excluding children.
69 VM_MAJFLT = 11, // Major page fault count excluding children.
70 VM_UTIME = 13, // Time scheduled in user mode in clock ticks.
71 VM_STIME = 14, // Time scheduled in kernel mode in clock ticks.
72 VM_NUMTHREADS = 19, // Number of threads.
73 VM_STARTTIME = 21, // The time the process started in clock ticks.
74 VM_VSIZE = 22, // Virtual memory size in bytes.
75 VM_RSS = 23, // Resident Set Size in pages.
76 };
77
78 // Reads the |field_num|th field from |proc_stats|. Returns 0 on failure.
79 // This version does not handle the first 3 values, since the first value is
80 // simply |pid|, and the next two values are strings.
81 int64_t GetProcStatsFieldAsInt64(const std::vector<std::string>& proc_stats,
82 ProcStatsFields field_num);
83
84 // Same as GetProcStatsFieldAsInt64(), but for size_t values.
85 size_t GetProcStatsFieldAsSizeT(const std::vector<std::string>& proc_stats,
86 ProcStatsFields field_num);
87
88 // Convenience wrappers around GetProcStatsFieldAsInt64(), ParseProcStats() and
89 // ReadProcStats(). See GetProcStatsFieldAsInt64() for details.
90 int64_t ReadStatsFilendGetFieldAsInt64(const FilePath& stat_file,
91 ProcStatsFields field_num);
92 int64_t ReadProcStatsAndGetFieldAsInt64(pid_t pid, ProcStatsFields field_num);
93 int64_t ReadProcSelfStatsAndGetFieldAsInt64(ProcStatsFields field_num);
94
95 // Same as ReadProcStatsAndGetFieldAsInt64() but for size_t values.
96 size_t ReadProcStatsAndGetFieldAsSizeT(pid_t pid,
97 ProcStatsFields field_num);
98
99 // Returns the time that the OS started. Clock ticks are relative to this.
100 Time GetBootTime();
101
102 // Returns the amount of time spent in user space since boot across all CPUs.
103 TimeDelta GetUserCpuTimeSinceBoot();
104
105 // Converts Linux clock ticks to a wall time delta.
106 TimeDelta ClockTicksToTimeDelta(int64_t clock_ticks);
107
108 // Executes the lambda for every task in the process's /proc/<pid>/task
109 // directory. The thread id and file path of the task directory are provided as
110 // arguments to the lambda.
111 template <typename Lambda>
ForEachProcessTask(base::ProcessHandle process,Lambda && lambda)112 void ForEachProcessTask(base::ProcessHandle process, Lambda&& lambda) {
113 // Iterate through the different threads tracked in /proc/<pid>/task.
114 FilePath fd_path = GetProcPidDir(process).Append("task");
115
116 DirReaderPosix dir_reader(fd_path.value().c_str());
117 if (!dir_reader.IsValid())
118 return;
119
120 for (; dir_reader.Next();) {
121 const char* tid_str = dir_reader.name();
122 if (strcmp(tid_str, ".") == 0 || strcmp(tid_str, "..") == 0)
123 continue;
124
125 PlatformThreadId tid;
126 if (!StringToInt(tid_str, &tid))
127 continue;
128
129 FilePath task_path = fd_path.Append(tid_str);
130 lambda(tid, task_path);
131 }
132 }
133
134 } // namespace internal
135 } // namespace base
136
137 #endif // BASE_PROCESS_INTERNAL_LINUX_H_
138