1 // Copyright (c) 2012 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 #include "base/process/internal_linux.h"
6
7 #include <limits.h>
8 #include <unistd.h>
9
10 #include <map>
11 #include <string>
12 #include <vector>
13
14 #include "base/files/file_util.h"
15 #include "base/logging.h"
16 #include "base/strings/string_number_conversions.h"
17 #include "base/strings/string_split.h"
18 #include "base/strings/string_util.h"
19 #include "base/threading/thread_restrictions.h"
20 #include "base/time/time.h"
21
22 namespace base {
23 namespace internal {
24
25 const char kProcDir[] = "/proc";
26
27 const char kStatFile[] = "stat";
28
GetProcPidDir(pid_t pid)29 FilePath GetProcPidDir(pid_t pid) {
30 return FilePath(kProcDir).Append(IntToString(pid));
31 }
32
ProcDirSlotToPid(const char * d_name)33 pid_t ProcDirSlotToPid(const char* d_name) {
34 int i;
35 for (i = 0; i < NAME_MAX && d_name[i]; ++i) {
36 if (!IsAsciiDigit(d_name[i])) {
37 return 0;
38 }
39 }
40 if (i == NAME_MAX)
41 return 0;
42
43 // Read the process's command line.
44 pid_t pid;
45 std::string pid_string(d_name);
46 if (!StringToInt(pid_string, &pid)) {
47 NOTREACHED();
48 return 0;
49 }
50 return pid;
51 }
52
ReadProcFile(const FilePath & file,std::string * buffer)53 bool ReadProcFile(const FilePath& file, std::string* buffer) {
54 buffer->clear();
55 // Synchronously reading files in /proc is safe.
56 ThreadRestrictions::ScopedAllowIO allow_io;
57
58 if (!ReadFileToString(file, buffer)) {
59 DLOG(WARNING) << "Failed to read " << file.MaybeAsASCII();
60 return false;
61 }
62 return !buffer->empty();
63 }
64
ReadProcStats(pid_t pid,std::string * buffer)65 bool ReadProcStats(pid_t pid, std::string* buffer) {
66 FilePath stat_file = internal::GetProcPidDir(pid).Append(kStatFile);
67 return ReadProcFile(stat_file, buffer);
68 }
69
ParseProcStats(const std::string & stats_data,std::vector<std::string> * proc_stats)70 bool ParseProcStats(const std::string& stats_data,
71 std::vector<std::string>* proc_stats) {
72 // |stats_data| may be empty if the process disappeared somehow.
73 // e.g. http://crbug.com/145811
74 if (stats_data.empty())
75 return false;
76
77 // The stat file is formatted as:
78 // pid (process name) data1 data2 .... dataN
79 // Look for the closing paren by scanning backwards, to avoid being fooled by
80 // processes with ')' in the name.
81 size_t open_parens_idx = stats_data.find(" (");
82 size_t close_parens_idx = stats_data.rfind(") ");
83 if (open_parens_idx == std::string::npos ||
84 close_parens_idx == std::string::npos ||
85 open_parens_idx > close_parens_idx) {
86 DLOG(WARNING) << "Failed to find matched parens in '" << stats_data << "'";
87 NOTREACHED();
88 return false;
89 }
90 open_parens_idx++;
91
92 proc_stats->clear();
93 // PID.
94 proc_stats->push_back(stats_data.substr(0, open_parens_idx));
95 // Process name without parentheses.
96 proc_stats->push_back(
97 stats_data.substr(open_parens_idx + 1,
98 close_parens_idx - (open_parens_idx + 1)));
99
100 // Split the rest.
101 std::vector<std::string> other_stats = SplitString(
102 stats_data.substr(close_parens_idx + 2), " ",
103 base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
104 for (size_t i = 0; i < other_stats.size(); ++i)
105 proc_stats->push_back(other_stats[i]);
106 return true;
107 }
108
109 typedef std::map<std::string, std::string> ProcStatMap;
ParseProcStat(const std::string & contents,ProcStatMap * output)110 void ParseProcStat(const std::string& contents, ProcStatMap* output) {
111 StringPairs key_value_pairs;
112 SplitStringIntoKeyValuePairs(contents, ' ', '\n', &key_value_pairs);
113 for (size_t i = 0; i < key_value_pairs.size(); ++i) {
114 output->insert(key_value_pairs[i]);
115 }
116 }
117
GetProcStatsFieldAsInt64(const std::vector<std::string> & proc_stats,ProcStatsFields field_num)118 int64_t GetProcStatsFieldAsInt64(const std::vector<std::string>& proc_stats,
119 ProcStatsFields field_num) {
120 DCHECK_GE(field_num, VM_PPID);
121 CHECK_LT(static_cast<size_t>(field_num), proc_stats.size());
122
123 int64_t value;
124 return StringToInt64(proc_stats[field_num], &value) ? value : 0;
125 }
126
GetProcStatsFieldAsSizeT(const std::vector<std::string> & proc_stats,ProcStatsFields field_num)127 size_t GetProcStatsFieldAsSizeT(const std::vector<std::string>& proc_stats,
128 ProcStatsFields field_num) {
129 DCHECK_GE(field_num, VM_PPID);
130 CHECK_LT(static_cast<size_t>(field_num), proc_stats.size());
131
132 size_t value;
133 return StringToSizeT(proc_stats[field_num], &value) ? value : 0;
134 }
135
ReadStatFileAndGetFieldAsInt64(const FilePath & stat_file,ProcStatsFields field_num)136 int64_t ReadStatFileAndGetFieldAsInt64(const FilePath& stat_file,
137 ProcStatsFields field_num) {
138 std::string stats_data;
139 if (!ReadProcFile(stat_file, &stats_data))
140 return 0;
141 std::vector<std::string> proc_stats;
142 if (!ParseProcStats(stats_data, &proc_stats))
143 return 0;
144 return GetProcStatsFieldAsInt64(proc_stats, field_num);
145 }
146
ReadProcStatsAndGetFieldAsInt64(pid_t pid,ProcStatsFields field_num)147 int64_t ReadProcStatsAndGetFieldAsInt64(pid_t pid, ProcStatsFields field_num) {
148 FilePath stat_file = internal::GetProcPidDir(pid).Append(kStatFile);
149 return ReadStatFileAndGetFieldAsInt64(stat_file, field_num);
150 }
151
ReadProcSelfStatsAndGetFieldAsInt64(ProcStatsFields field_num)152 int64_t ReadProcSelfStatsAndGetFieldAsInt64(ProcStatsFields field_num) {
153 FilePath stat_file = FilePath(kProcDir).Append("self").Append(kStatFile);
154 return ReadStatFileAndGetFieldAsInt64(stat_file, field_num);
155 }
156
ReadProcStatsAndGetFieldAsSizeT(pid_t pid,ProcStatsFields field_num)157 size_t ReadProcStatsAndGetFieldAsSizeT(pid_t pid,
158 ProcStatsFields field_num) {
159 std::string stats_data;
160 if (!ReadProcStats(pid, &stats_data))
161 return 0;
162 std::vector<std::string> proc_stats;
163 if (!ParseProcStats(stats_data, &proc_stats))
164 return 0;
165 return GetProcStatsFieldAsSizeT(proc_stats, field_num);
166 }
167
GetBootTime()168 Time GetBootTime() {
169 FilePath path("/proc/stat");
170 std::string contents;
171 if (!ReadProcFile(path, &contents))
172 return Time();
173 ProcStatMap proc_stat;
174 ParseProcStat(contents, &proc_stat);
175 ProcStatMap::const_iterator btime_it = proc_stat.find("btime");
176 if (btime_it == proc_stat.end())
177 return Time();
178 int btime;
179 if (!StringToInt(btime_it->second, &btime))
180 return Time();
181 return Time::FromTimeT(btime);
182 }
183
GetUserCpuTimeSinceBoot()184 TimeDelta GetUserCpuTimeSinceBoot() {
185 FilePath path("/proc/stat");
186 std::string contents;
187 if (!ReadProcFile(path, &contents))
188 return TimeDelta();
189
190 ProcStatMap proc_stat;
191 ParseProcStat(contents, &proc_stat);
192 ProcStatMap::const_iterator cpu_it = proc_stat.find("cpu");
193 if (cpu_it == proc_stat.end())
194 return TimeDelta();
195
196 std::vector<std::string> cpu = SplitString(
197 cpu_it->second, kWhitespaceASCII, TRIM_WHITESPACE, SPLIT_WANT_NONEMPTY);
198
199 if (cpu.size() < 2 || cpu[0] != "cpu")
200 return TimeDelta();
201
202 uint64_t user;
203 uint64_t nice;
204 if (!StringToUint64(cpu[0], &user) || !StringToUint64(cpu[1], &nice))
205 return TimeDelta();
206
207 return ClockTicksToTimeDelta(user + nice);
208 }
209
ClockTicksToTimeDelta(int clock_ticks)210 TimeDelta ClockTicksToTimeDelta(int clock_ticks) {
211 // This queries the /proc-specific scaling factor which is
212 // conceptually the system hertz. To dump this value on another
213 // system, try
214 // od -t dL /proc/self/auxv
215 // and look for the number after 17 in the output; mine is
216 // 0000040 17 100 3 134512692
217 // which means the answer is 100.
218 // It may be the case that this value is always 100.
219 static const int kHertz = sysconf(_SC_CLK_TCK);
220
221 return TimeDelta::FromMicroseconds(
222 Time::kMicrosecondsPerSecond * clock_ticks / kHertz);
223 }
224
225 } // namespace internal
226 } // namespace base
227