1/*
2 * Copyright (C) 2016 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#pragma once
18
19#include <dirent.h>
20#include <fcntl.h>
21#include <stdlib.h>
22#include <sys/types.h>
23#include <unistd.h>
24
25#include <memory>
26#include <string>
27#include <type_traits>
28
29#include <android-base/logging.h>
30#include <android-base/parseint.h>
31#include <android-base/unique_fd.h>
32
33namespace android {
34namespace procinfo {
35
36#if defined(__linux__)
37
38enum ProcessState {
39  kProcessStateUnknown,
40  kProcessStateRunning,
41  kProcessStateSleeping,
42  kProcessStateUninterruptibleWait,
43  kProcessStateStopped,
44  kProcessStateZombie,
45};
46
47struct ProcessInfo {
48  std::string name;
49  ProcessState state;
50  pid_t tid;
51  pid_t pid;
52  pid_t ppid;
53  pid_t tracer;
54  uid_t uid;
55  uid_t gid;
56};
57
58// Parse the contents of /proc/<tid>/status into |process_info|.
59bool GetProcessInfo(pid_t tid, ProcessInfo* process_info);
60
61// Parse the contents of <fd>/status into |process_info|.
62// |fd| should be an fd pointing at a /proc/<pid> directory.
63bool GetProcessInfoFromProcPidFd(int fd, ProcessInfo* process_info);
64
65// Fetch the list of threads from a given process's /proc/<pid> directory.
66// |fd| should be an fd pointing at a /proc/<pid> directory.
67template <typename Collection>
68auto GetProcessTidsFromProcPidFd(int fd, Collection* out) ->
69    typename std::enable_if<sizeof(typename Collection::value_type) >= sizeof(pid_t), bool>::type {
70  out->clear();
71
72  int task_fd = openat(fd, "task", O_DIRECTORY | O_RDONLY | O_CLOEXEC);
73  std::unique_ptr<DIR, int (*)(DIR*)> dir(fdopendir(task_fd), closedir);
74  if (!dir) {
75    PLOG(ERROR) << "failed to open task directory";
76    return false;
77  }
78
79  struct dirent* dent;
80  while ((dent = readdir(dir.get()))) {
81    if (strcmp(dent->d_name, ".") != 0 && strcmp(dent->d_name, "..") != 0) {
82      pid_t tid;
83      if (!android::base::ParseInt(dent->d_name, &tid, 1, std::numeric_limits<pid_t>::max())) {
84        LOG(ERROR) << "failed to parse task id: " << dent->d_name;
85        return false;
86      }
87
88      out->insert(out->end(), tid);
89    }
90  }
91
92  return true;
93}
94
95template <typename Collection>
96auto GetProcessTids(pid_t pid, Collection* out) ->
97    typename std::enable_if<sizeof(typename Collection::value_type) >= sizeof(pid_t), bool>::type {
98  char task_path[PATH_MAX];
99  if (snprintf(task_path, PATH_MAX, "/proc/%d", pid) >= PATH_MAX) {
100    LOG(ERROR) << "task path overflow (pid = " << pid << ")";
101    return false;
102  }
103
104  android::base::unique_fd fd(open(task_path, O_DIRECTORY | O_RDONLY | O_CLOEXEC));
105  if (fd == -1) {
106    PLOG(ERROR) << "failed to open " << task_path;
107    return false;
108  }
109
110  return GetProcessTidsFromProcPidFd(fd.get(), out);
111}
112
113#endif
114
115} /* namespace procinfo */
116} /* namespace android */
117