blob: b68aee54ed043f3d9a91ec58d0aa15e7cc562e41 [file] [log] [blame]
// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/process/process_iterator.h"
#include <stddef.h>
#include "base/files/file_util.h"
#include "base/logging.h"
#include "base/notreached.h"
#include "base/numerics/safe_conversions.h"
#include "base/process/internal_linux.h"
#include "base/strings/string_split.h"
#include "base/strings/string_util.h"
#include "base/threading/thread_restrictions.h"
namespace base {
class ScopedAllowBlockingForProc : public ScopedAllowBlocking {};
namespace {
// Reads the |field_num|th field from |proc_stats|.
// Returns an empty string on failure.
// This version only handles VM_COMM and VM_STATE, which are the only fields
// that are strings.
std::string GetProcStatsFieldAsString(
const std::vector<std::string>& proc_stats,
internal::ProcStatsFields field_num) {
if (field_num < internal::VM_COMM || field_num > internal::VM_STATE) {
NOTREACHED();
return std::string();
}
if (proc_stats.size() > static_cast<size_t>(field_num))
return proc_stats[field_num];
NOTREACHED();
return std::string();
}
// Reads /proc/<pid>/cmdline and populates |proc_cmd_line_args| with the command
// line arguments. Returns true if successful.
// Note: /proc/<pid>/cmdline contains command line arguments separated by single
// null characters. We tokenize it into a vector of strings using '\0' as a
// delimiter.
bool GetProcCmdline(pid_t pid, std::vector<std::string>* proc_cmd_line_args) {
// Synchronously reading files in /proc is safe.
ScopedAllowBlockingForProc allow_blocking;
FilePath cmd_line_file = internal::GetProcPidDir(pid).Append("cmdline");
std::string cmd_line;
if (!ReadFileToString(cmd_line_file, &cmd_line))
return false;
std::string delimiters;
delimiters.push_back('\0');
*proc_cmd_line_args = SplitString(cmd_line, delimiters, KEEP_WHITESPACE,
SPLIT_WANT_NONEMPTY);
return true;
}
} // namespace
ProcessIterator::ProcessIterator(const ProcessFilter* filter)
: procfs_dir_(opendir(internal::kProcDir)), filter_(filter) {
if (!procfs_dir_) {
// On Android, SELinux may prevent reading /proc. See
// https://crbug.com/581517 for details.
PLOG(ERROR) << "opendir " << internal::kProcDir;
}
}
ProcessIterator::~ProcessIterator() = default;
bool ProcessIterator::CheckForNextProcess() {
// TODO(port): skip processes owned by different UID
if (!procfs_dir_) {
DLOG(ERROR) << "Skipping CheckForNextProcess(), no procfs_dir_";
return false;
}
pid_t pid = kNullProcessId;
std::vector<std::string> cmd_line_args;
std::string stats_data;
std::vector<std::string> proc_stats;
while (true) {
dirent* const slot = readdir(procfs_dir_.get());
// all done looking through /proc?
if (!slot)
return false;
// If not a process, keep looking for one.
pid = internal::ProcDirSlotToPid(slot->d_name);
if (!pid) {
continue;
}
if (!GetProcCmdline(pid, &cmd_line_args))
continue;
if (!internal::ReadProcStats(pid, &stats_data))
continue;
if (!internal::ParseProcStats(stats_data, &proc_stats))
continue;
std::string runstate =
GetProcStatsFieldAsString(proc_stats, internal::VM_STATE);
if (runstate.size() != 1) {
NOTREACHED();
continue;
}
// Is the process in 'Zombie' state, i.e. dead but waiting to be reaped?
// Allowed values: D R S T Z
if (runstate[0] != 'Z')
break;
// Nope, it's a zombie; somebody isn't cleaning up after their children.
// (e.g. WaitForProcessesToExit doesn't clean up after dead children yet.)
// There could be a lot of zombies, can't really decrement i here.
}
entry_.pid_ = pid;
entry_.ppid_ = checked_cast<ProcessId>(
GetProcStatsFieldAsInt64(proc_stats, internal::VM_PPID));
entry_.gid_ = checked_cast<ProcessId>(
GetProcStatsFieldAsInt64(proc_stats, internal::VM_PGRP));
entry_.cmd_line_args_.assign(cmd_line_args.begin(), cmd_line_args.end());
entry_.exe_file_ = GetProcessExecutablePath(pid).BaseName().value();
return true;
}
bool NamedProcessIterator::IncludeEntry() {
if (executable_name_ != entry().exe_file())
return false;
return ProcessIterator::IncludeEntry();
}
} // namespace base