tasklist.cpp revision 66dd09e8e2407082ce93bf0784de641298131912 
1// Copyright (C) 2015 The Android Open Source Project
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//      http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15#include <sys/types.h>
16#include <dirent.h>
17#include <errno.h>
18#include <stdlib.h>
19#include <string.h>
20
21#include <map>
22#include <memory>
23#include <string>
24#include <vector>
25
26#include <android-base/stringprintf.h>
27
28#include "tasklist.h"
29
30template<typename Func>
31static bool ScanPidsInDir(std::string name, Func f) {
32  std::unique_ptr<DIR, decltype(&closedir)> dir(opendir(name.c_str()), closedir);
33  if (!dir) {
34    return false;
35  }
36
37  dirent* entry;
38  while ((entry = readdir(dir.get())) != nullptr) {
39    if (isdigit(entry->d_name[0])) {
40      pid_t pid = atoi(entry->d_name);
41      f(pid);
42    }
43  }
44
45  return true;
46}
47
48bool TaskList::Scan(std::map<pid_t, std::vector<pid_t>>& tgid_map) {
49  tgid_map.clear();
50
51  return ScanPidsInDir("/proc", [&tgid_map](pid_t tgid) {
52    std::vector<pid_t> pid_list;
53    if (ScanPid(tgid, pid_list)) {
54      tgid_map.insert({tgid, pid_list});
55    }
56  });
57}
58
59bool TaskList::ScanPid(pid_t tgid, std::vector<pid_t>& pid_list) {
60  std::string filename = android::base::StringPrintf("/proc/%d/task", tgid);
61
62  return ScanPidsInDir(filename, [&pid_list](pid_t pid) {
63    pid_list.push_back(pid);
64  });
65}
66