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 #include <procinfo/process.h>
18
19 #include <fcntl.h>
20 #include <stdio.h>
21 #include <stdlib.h>
22 #include <string.h>
23 #include <unistd.h>
24
25 #include <string>
26
27 #include <android-base/unique_fd.h>
28
29 using android::base::unique_fd;
30
31 namespace android {
32 namespace procinfo {
33
GetProcessInfo(pid_t tid,ProcessInfo * process_info)34 bool GetProcessInfo(pid_t tid, ProcessInfo* process_info) {
35 char path[PATH_MAX];
36 snprintf(path, sizeof(path), "/proc/%d", tid);
37
38 unique_fd dirfd(open(path, O_DIRECTORY | O_RDONLY));
39 if (dirfd == -1) {
40 PLOG(ERROR) << "failed to open " << path;
41 return false;
42 }
43
44 return GetProcessInfoFromProcPidFd(dirfd.get(), process_info);
45 }
46
parse_state(const char * state)47 static ProcessState parse_state(const char* state) {
48 switch (*state) {
49 case 'R':
50 return kProcessStateRunning;
51 case 'S':
52 return kProcessStateSleeping;
53 case 'D':
54 return kProcessStateUninterruptibleWait;
55 case 'T':
56 return kProcessStateStopped;
57 case 'Z':
58 return kProcessStateZombie;
59 default:
60 LOG(ERROR) << "unknown process state: " << *state;
61 return kProcessStateUnknown;
62 }
63 }
64
GetProcessInfoFromProcPidFd(int fd,ProcessInfo * process_info)65 bool GetProcessInfoFromProcPidFd(int fd, ProcessInfo* process_info) {
66 int status_fd = openat(fd, "status", O_RDONLY | O_CLOEXEC);
67
68 if (status_fd == -1) {
69 PLOG(ERROR) << "failed to open status fd in GetProcessInfoFromProcPidFd";
70 return false;
71 }
72
73 std::unique_ptr<FILE, decltype(&fclose)> fp(fdopen(status_fd, "r"), fclose);
74 if (!fp) {
75 PLOG(ERROR) << "failed to open status file in GetProcessInfoFromProcPidFd";
76 close(status_fd);
77 return false;
78 }
79
80 int field_bitmap = 0;
81 static constexpr int finished_bitmap = 255;
82 char* line = nullptr;
83 size_t len = 0;
84
85 while (getline(&line, &len, fp.get()) != -1 && field_bitmap != finished_bitmap) {
86 char* tab = strchr(line, '\t');
87 if (tab == nullptr) {
88 continue;
89 }
90
91 size_t header_len = tab - line;
92 std::string header = std::string(line, header_len);
93 if (header == "Name:") {
94 std::string name = line + header_len + 1;
95
96 // line includes the trailing newline.
97 name.pop_back();
98 process_info->name = std::move(name);
99
100 field_bitmap |= 1;
101 } else if (header == "Pid:") {
102 process_info->tid = atoi(tab + 1);
103 field_bitmap |= 2;
104 } else if (header == "Tgid:") {
105 process_info->pid = atoi(tab + 1);
106 field_bitmap |= 4;
107 } else if (header == "PPid:") {
108 process_info->ppid = atoi(tab + 1);
109 field_bitmap |= 8;
110 } else if (header == "TracerPid:") {
111 process_info->tracer = atoi(tab + 1);
112 field_bitmap |= 16;
113 } else if (header == "Uid:") {
114 process_info->uid = atoi(tab + 1);
115 field_bitmap |= 32;
116 } else if (header == "Gid:") {
117 process_info->gid = atoi(tab + 1);
118 field_bitmap |= 64;
119 } else if (header == "State:") {
120 process_info->state = parse_state(tab + 1);
121 field_bitmap |= 128;
122 }
123 }
124
125 free(line);
126 return field_bitmap == finished_bitmap;
127 }
128
129 } /* namespace procinfo */
130 } /* namespace android */
131