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