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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/process/internal_linux.h"
#include <unistd.h>
#include <map>
#include <string>
#include <vector>
#include "base/files/file_util.h"
#include "base/logging.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_split.h"
#include "base/strings/string_util.h"
#include "base/threading/thread_restrictions.h"
#include "base/time/time.h"
namespace base {
namespace internal {
const char kProcDir[] = "/proc";
const char kStatFile[] = "stat";
base::FilePath GetProcPidDir(pid_t pid) {
return base::FilePath(kProcDir).Append(IntToString(pid));
}
pid_t ProcDirSlotToPid(const char* d_name) {
int i;
for (i = 0; i < NAME_MAX && d_name[i]; ++i) {
if (!IsAsciiDigit(d_name[i])) {
return 0;
}
}
if (i == NAME_MAX)
return 0;
// Read the process's command line.
pid_t pid;
std::string pid_string(d_name);
if (!StringToInt(pid_string, &pid)) {
NOTREACHED();
return 0;
}
return pid;
}
bool ReadProcFile(const FilePath& file, std::string* buffer) {
buffer->clear();
// Synchronously reading files in /proc is safe.
ThreadRestrictions::ScopedAllowIO allow_io;
if (!ReadFileToString(file, buffer)) {
DLOG(WARNING) << "Failed to read " << file.MaybeAsASCII();
return false;
}
return !buffer->empty();
}
bool ReadProcStats(pid_t pid, std::string* buffer) {
FilePath stat_file = internal::GetProcPidDir(pid).Append(kStatFile);
return ReadProcFile(stat_file, buffer);
}
bool ParseProcStats(const std::string& stats_data,
std::vector<std::string>* proc_stats) {
// |stats_data| may be empty if the process disappeared somehow.
// e.g. http://crbug.com/145811
if (stats_data.empty())
return false;
// The stat file is formatted as:
// pid (process name) data1 data2 .... dataN
// Look for the closing paren by scanning backwards, to avoid being fooled by
// processes with ')' in the name.
size_t open_parens_idx = stats_data.find(" (");
size_t close_parens_idx = stats_data.rfind(") ");
if (open_parens_idx == std::string::npos ||
close_parens_idx == std::string::npos ||
open_parens_idx > close_parens_idx) {
DLOG(WARNING) << "Failed to find matched parens in '" << stats_data << "'";
NOTREACHED();
return false;
}
open_parens_idx++;
proc_stats->clear();
// PID.
proc_stats->push_back(stats_data.substr(0, open_parens_idx));
// Process name without parentheses.
proc_stats->push_back(
stats_data.substr(open_parens_idx + 1,
close_parens_idx - (open_parens_idx + 1)));
// Split the rest.
std::vector<std::string> other_stats;
SplitString(stats_data.substr(close_parens_idx + 2), ' ', &other_stats);
for (size_t i = 0; i < other_stats.size(); ++i)
proc_stats->push_back(other_stats[i]);
return true;
}
typedef std::map<std::string, std::string> ProcStatMap;
void ParseProcStat(const std::string& contents, ProcStatMap* output) {
typedef std::pair<std::string, std::string> StringPair;
std::vector<StringPair> key_value_pairs;
SplitStringIntoKeyValuePairs(contents, ' ', '\n', &key_value_pairs);
for (size_t i = 0; i < key_value_pairs.size(); ++i) {
const StringPair& key_value_pair = key_value_pairs[i];
output->insert(key_value_pair);
}
}
int64 GetProcStatsFieldAsInt64(const std::vector<std::string>& proc_stats,
ProcStatsFields field_num) {
DCHECK_GE(field_num, VM_PPID);
CHECK_LT(static_cast<size_t>(field_num), proc_stats.size());
int64 value;
return StringToInt64(proc_stats[field_num], &value) ? value : 0;
}
size_t GetProcStatsFieldAsSizeT(const std::vector<std::string>& proc_stats,
ProcStatsFields field_num) {
DCHECK_GE(field_num, VM_PPID);
CHECK_LT(static_cast<size_t>(field_num), proc_stats.size());
size_t value;
return StringToSizeT(proc_stats[field_num], &value) ? value : 0;
}
int64 ReadProcStatsAndGetFieldAsInt64(pid_t pid, ProcStatsFields field_num) {
std::string stats_data;
if (!ReadProcStats(pid, &stats_data))
return 0;
std::vector<std::string> proc_stats;
if (!ParseProcStats(stats_data, &proc_stats))
return 0;
return GetProcStatsFieldAsInt64(proc_stats, field_num);
}
size_t ReadProcStatsAndGetFieldAsSizeT(pid_t pid,
ProcStatsFields field_num) {
std::string stats_data;
if (!ReadProcStats(pid, &stats_data))
return 0;
std::vector<std::string> proc_stats;
if (!ParseProcStats(stats_data, &proc_stats))
return 0;
return GetProcStatsFieldAsSizeT(proc_stats, field_num);
}
Time GetBootTime() {
FilePath path("/proc/stat");
std::string contents;
if (!ReadProcFile(path, &contents))
return Time();
ProcStatMap proc_stat;
ParseProcStat(contents, &proc_stat);
ProcStatMap::const_iterator btime_it = proc_stat.find("btime");
if (btime_it == proc_stat.end())
return Time();
int btime;
if (!StringToInt(btime_it->second, &btime))
return Time();
return Time::FromTimeT(btime);
}
TimeDelta ClockTicksToTimeDelta(int clock_ticks) {
// This queries the /proc-specific scaling factor which is
// conceptually the system hertz. To dump this value on another
// system, try
// od -t dL /proc/self/auxv
// and look for the number after 17 in the output; mine is
// 0000040 17 100 3 134512692
// which means the answer is 100.
// It may be the case that this value is always 100.
static const int kHertz = sysconf(_SC_CLK_TCK);
return TimeDelta::FromMicroseconds(
Time::kMicrosecondsPerSecond * clock_ticks / kHertz);
}
} // namespace internal
} // namespace base
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