1 /*
2 * Copyright (C) 2008 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 <ctype.h>
18 #include <dirent.h>
19 #include <errno.h>
20 #include <fcntl.h>
21 #include <fts.h>
22 #include <poll.h>
23 #include <pwd.h>
24 #include <signal.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <string.h>
28 #include <sys/stat.h>
29 #include <unistd.h>
30
31 #include <fstream>
32 #include <mntent.h>
33 #include <unordered_set>
34
35 #include <android-base/file.h>
36 #include <android-base/logging.h>
37 #include <android-base/parseint.h>
38 #include <android-base/stringprintf.h>
39 #include <android-base/strings.h>
40
41 #include "Process.h"
42
43 using android::base::StringPrintf;
44
45 namespace android {
46 namespace vold {
47
checkMaps(const std::string & path,const std::string & prefix)48 static bool checkMaps(const std::string& path, const std::string& prefix) {
49 bool found = false;
50 auto file = std::unique_ptr<FILE, decltype(&fclose)>{fopen(path.c_str(), "re"), fclose};
51 if (!file) {
52 return false;
53 }
54
55 char* buf = nullptr;
56 size_t len = 0;
57 while (getline(&buf, &len, file.get()) != -1) {
58 std::string line(buf);
59 std::string::size_type pos = line.find('/');
60 if (pos != std::string::npos) {
61 line = line.substr(pos);
62 if (android::base::StartsWith(line, prefix)) {
63 LOG(WARNING) << "Found map " << path << " referencing " << line;
64 found = true;
65 break;
66 }
67 }
68 }
69 free(buf);
70
71 return found;
72 }
73
checkSymlink(const std::string & path,const std::string & prefix)74 static bool checkSymlink(const std::string& path, const std::string& prefix) {
75 std::string res;
76 if (android::base::Readlink(path, &res)) {
77 if (android::base::StartsWith(res, prefix)) {
78 LOG(WARNING) << "Found symlink " << path << " referencing " << res;
79 return true;
80 }
81 }
82 return false;
83 }
84
85 // TODO: Refactor the code with KillProcessesWithOpenFiles().
KillProcessesWithMounts(const std::string & prefix,int signal)86 int KillProcessesWithMounts(const std::string& prefix, int signal) {
87 std::unordered_set<pid_t> pids;
88
89 auto proc_d = std::unique_ptr<DIR, int (*)(DIR*)>(opendir("/proc"), closedir);
90 if (!proc_d) {
91 PLOG(ERROR) << "Failed to open proc";
92 return -1;
93 }
94
95 struct dirent* proc_de;
96 while ((proc_de = readdir(proc_d.get())) != nullptr) {
97 // We only care about valid PIDs
98 pid_t pid;
99 if (proc_de->d_type != DT_DIR) continue;
100 if (!android::base::ParseInt(proc_de->d_name, &pid)) continue;
101
102 // Look for references to prefix
103 std::string mounts_file(StringPrintf("/proc/%d/mounts", pid));
104 auto fp = std::unique_ptr<FILE, int (*)(FILE*)>(
105 setmntent(mounts_file.c_str(), "r"), endmntent);
106 if (!fp) {
107 PLOG(WARNING) << "Failed to open " << mounts_file;
108 continue;
109 }
110
111 // Check if obb directory is mounted, and get all packages of mounted app data directory.
112 mntent* mentry;
113 while ((mentry = getmntent(fp.get())) != nullptr) {
114 if (android::base::StartsWith(mentry->mnt_dir, prefix)) {
115 pids.insert(pid);
116 break;
117 }
118 }
119 }
120 if (signal != 0) {
121 for (const auto& pid : pids) {
122 LOG(WARNING) << "Killing pid "<< pid << " with signal " << strsignal(signal) <<
123 " because it has a mount with prefix " << prefix;
124 kill(pid, signal);
125 }
126 }
127 return pids.size();
128 }
129
KillProcessesWithOpenFiles(const std::string & prefix,int signal)130 int KillProcessesWithOpenFiles(const std::string& prefix, int signal) {
131 std::unordered_set<pid_t> pids;
132
133 auto proc_d = std::unique_ptr<DIR, int (*)(DIR*)>(opendir("/proc"), closedir);
134 if (!proc_d) {
135 PLOG(ERROR) << "Failed to open proc";
136 return -1;
137 }
138
139 struct dirent* proc_de;
140 while ((proc_de = readdir(proc_d.get())) != nullptr) {
141 // We only care about valid PIDs
142 pid_t pid;
143 if (proc_de->d_type != DT_DIR) continue;
144 if (!android::base::ParseInt(proc_de->d_name, &pid)) continue;
145
146 // Look for references to prefix
147 bool found = false;
148 auto path = StringPrintf("/proc/%d", pid);
149 found |= checkMaps(path + "/maps", prefix);
150 found |= checkSymlink(path + "/cwd", prefix);
151 found |= checkSymlink(path + "/root", prefix);
152 found |= checkSymlink(path + "/exe", prefix);
153
154 auto fd_path = path + "/fd";
155 auto fd_d = std::unique_ptr<DIR, int (*)(DIR*)>(opendir(fd_path.c_str()), closedir);
156 if (!fd_d) {
157 PLOG(WARNING) << "Failed to open " << fd_path;
158 } else {
159 struct dirent* fd_de;
160 while ((fd_de = readdir(fd_d.get())) != nullptr) {
161 if (fd_de->d_type != DT_LNK) continue;
162 found |= checkSymlink(fd_path + "/" + fd_de->d_name, prefix);
163 }
164 }
165
166 if (found) {
167 pids.insert(pid);
168 }
169 }
170 if (signal != 0) {
171 for (const auto& pid : pids) {
172 LOG(WARNING) << "Sending " << strsignal(signal) << " to " << pid;
173 kill(pid, signal);
174 }
175 }
176 return pids.size();
177 }
178
179 } // namespace vold
180 } // namespace android
181