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 // Not defined on AIX by default.
23 #if defined(OS_AIX)
24 #define NAME_MAX 255
25 #endif
26
27 namespace base {
28 namespace internal {
29
30 const char kProcDir[] = "/proc";
31
32 const char kStatFile[] = "stat";
33
GetProcPidDir(pid_t pid)34 FilePath GetProcPidDir(pid_t pid) {
35 return FilePath(kProcDir).Append(IntToString(pid));
36 }
37
ProcDirSlotToPid(const char * d_name)38 pid_t ProcDirSlotToPid(const char* d_name) {
39 int i;
40 for (i = 0; i < NAME_MAX && d_name[i]; ++i) {
41 if (!IsAsciiDigit(d_name[i])) {
42 return 0;
43 }
44 }
45 if (i == NAME_MAX)
46 return 0;
47
48 // Read the process's command line.
49 pid_t pid;
50 std::string pid_string(d_name);
51 if (!StringToInt(pid_string, &pid)) {
52 NOTREACHED();
53 return 0;
54 }
55 return pid;
56 }
57
ReadProcFile(const FilePath & file,std::string * buffer)58 bool ReadProcFile(const FilePath& file, std::string* buffer) {
59 buffer->clear();
60 // Synchronously reading files in /proc is safe.
61 ThreadRestrictions::ScopedAllowIO allow_io;
62
63 if (!ReadFileToString(file, buffer)) {
64 DLOG(WARNING) << "Failed to read " << file.MaybeAsASCII();
65 return false;
66 }
67 return !buffer->empty();
68 }
69
ReadProcStats(pid_t pid,std::string * buffer)70 bool ReadProcStats(pid_t pid, std::string* buffer) {
71 FilePath stat_file = internal::GetProcPidDir(pid).Append(kStatFile);
72 return ReadProcFile(stat_file, buffer);
73 }
74
ParseProcStats(const std::string & stats_data,std::vector<std::string> * proc_stats)75 bool ParseProcStats(const std::string& stats_data,
76 std::vector<std::string>* proc_stats) {
77 // |stats_data| may be empty if the process disappeared somehow.
78 // e.g. http://crbug.com/145811
79 if (stats_data.empty())
80 return false;
81
82 // The stat file is formatted as:
83 // pid (process name) data1 data2 .... dataN
84 // Look for the closing paren by scanning backwards, to avoid being fooled by
85 // processes with ')' in the name.
86 size_t open_parens_idx = stats_data.find(" (");
87 size_t close_parens_idx = stats_data.rfind(") ");
88 if (open_parens_idx == std::string::npos ||
89 close_parens_idx == std::string::npos ||
90 open_parens_idx > close_parens_idx) {
91 DLOG(WARNING) << "Failed to find matched parens in '" << stats_data << "'";
92 NOTREACHED();
93 return false;
94 }
95 open_parens_idx++;
96
97 proc_stats->clear();
98 // PID.
99 proc_stats->push_back(stats_data.substr(0, open_parens_idx));
100 // Process name without parentheses.
101 proc_stats->push_back(
102 stats_data.substr(open_parens_idx + 1,
103 close_parens_idx - (open_parens_idx + 1)));
104
105 // Split the rest.
106 std::vector<std::string> other_stats = SplitString(
107 stats_data.substr(close_parens_idx + 2), " ",
108 base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
109 for (size_t i = 0; i < other_stats.size(); ++i)
110 proc_stats->push_back(other_stats[i]);
111 return true;
112 }
113
114 typedef std::map<std::string, std::string> ProcStatMap;
ParseProcStat(const std::string & contents,ProcStatMap * output)115 void ParseProcStat(const std::string& contents, ProcStatMap* output) {
116 StringPairs key_value_pairs;
117 SplitStringIntoKeyValuePairs(contents, ' ', '\n', &key_value_pairs);
118 for (size_t i = 0; i < key_value_pairs.size(); ++i) {
119 output->insert(key_value_pairs[i]);
120 }
121 }
122
GetProcStatsFieldAsInt64(const std::vector<std::string> & proc_stats,ProcStatsFields field_num)123 int64_t GetProcStatsFieldAsInt64(const std::vector<std::string>& proc_stats,
124 ProcStatsFields field_num) {
125 DCHECK_GE(field_num, VM_PPID);
126 CHECK_LT(static_cast<size_t>(field_num), proc_stats.size());
127
128 int64_t value;
129 return StringToInt64(proc_stats[field_num], &value) ? value : 0;
130 }
131
GetProcStatsFieldAsSizeT(const std::vector<std::string> & proc_stats,ProcStatsFields field_num)132 size_t GetProcStatsFieldAsSizeT(const std::vector<std::string>& proc_stats,
133 ProcStatsFields field_num) {
134 DCHECK_GE(field_num, VM_PPID);
135 CHECK_LT(static_cast<size_t>(field_num), proc_stats.size());
136
137 size_t value;
138 return StringToSizeT(proc_stats[field_num], &value) ? value : 0;
139 }
140
ReadStatFileAndGetFieldAsInt64(const FilePath & stat_file,ProcStatsFields field_num)141 int64_t ReadStatFileAndGetFieldAsInt64(const FilePath& stat_file,
142 ProcStatsFields field_num) {
143 std::string stats_data;
144 if (!ReadProcFile(stat_file, &stats_data))
145 return 0;
146 std::vector<std::string> proc_stats;
147 if (!ParseProcStats(stats_data, &proc_stats))
148 return 0;
149 return GetProcStatsFieldAsInt64(proc_stats, field_num);
150 }
151
ReadProcStatsAndGetFieldAsInt64(pid_t pid,ProcStatsFields field_num)152 int64_t ReadProcStatsAndGetFieldAsInt64(pid_t pid, ProcStatsFields field_num) {
153 FilePath stat_file = internal::GetProcPidDir(pid).Append(kStatFile);
154 return ReadStatFileAndGetFieldAsInt64(stat_file, field_num);
155 }
156
ReadProcSelfStatsAndGetFieldAsInt64(ProcStatsFields field_num)157 int64_t ReadProcSelfStatsAndGetFieldAsInt64(ProcStatsFields field_num) {
158 FilePath stat_file = FilePath(kProcDir).Append("self").Append(kStatFile);
159 return ReadStatFileAndGetFieldAsInt64(stat_file, field_num);
160 }
161
ReadProcStatsAndGetFieldAsSizeT(pid_t pid,ProcStatsFields field_num)162 size_t ReadProcStatsAndGetFieldAsSizeT(pid_t pid,
163 ProcStatsFields field_num) {
164 std::string stats_data;
165 if (!ReadProcStats(pid, &stats_data))
166 return 0;
167 std::vector<std::string> proc_stats;
168 if (!ParseProcStats(stats_data, &proc_stats))
169 return 0;
170 return GetProcStatsFieldAsSizeT(proc_stats, field_num);
171 }
172
GetBootTime()173 Time GetBootTime() {
174 FilePath path("/proc/stat");
175 std::string contents;
176 if (!ReadProcFile(path, &contents))
177 return Time();
178 ProcStatMap proc_stat;
179 ParseProcStat(contents, &proc_stat);
180 ProcStatMap::const_iterator btime_it = proc_stat.find("btime");
181 if (btime_it == proc_stat.end())
182 return Time();
183 int btime;
184 if (!StringToInt(btime_it->second, &btime))
185 return Time();
186 return Time::FromTimeT(btime);
187 }
188
GetUserCpuTimeSinceBoot()189 TimeDelta GetUserCpuTimeSinceBoot() {
190 FilePath path("/proc/stat");
191 std::string contents;
192 if (!ReadProcFile(path, &contents))
193 return TimeDelta();
194
195 ProcStatMap proc_stat;
196 ParseProcStat(contents, &proc_stat);
197 ProcStatMap::const_iterator cpu_it = proc_stat.find("cpu");
198 if (cpu_it == proc_stat.end())
199 return TimeDelta();
200
201 std::vector<std::string> cpu = SplitString(
202 cpu_it->second, kWhitespaceASCII, TRIM_WHITESPACE, SPLIT_WANT_NONEMPTY);
203
204 if (cpu.size() < 2 || cpu[0] != "cpu")
205 return TimeDelta();
206
207 uint64_t user;
208 uint64_t nice;
209 if (!StringToUint64(cpu[0], &user) || !StringToUint64(cpu[1], &nice))
210 return TimeDelta();
211
212 return ClockTicksToTimeDelta(user + nice);
213 }
214
ClockTicksToTimeDelta(int clock_ticks)215 TimeDelta ClockTicksToTimeDelta(int clock_ticks) {
216 // This queries the /proc-specific scaling factor which is
217 // conceptually the system hertz. To dump this value on another
218 // system, try
219 // od -t dL /proc/self/auxv
220 // and look for the number after 17 in the output; mine is
221 // 0000040 17 100 3 134512692
222 // which means the answer is 100.
223 // It may be the case that this value is always 100.
224 static const int kHertz = sysconf(_SC_CLK_TCK);
225
226 return TimeDelta::FromMicroseconds(
227 Time::kMicrosecondsPerSecond * clock_ticks / kHertz);
228 }
229
230 } // namespace internal
231 } // namespace base
232