1 /*
2  * Copyright (C) 2015 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 #define TRACE_TAG ADB
18 
19 #include "sysdeps.h"
20 
21 #include <signal.h>
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <unistd.h>
25 
26 #include <thread>
27 
28 #include <android-base/errors.h>
29 #include <android-base/file.h>
30 #include <android-base/logging.h>
31 #include <android-base/stringprintf.h>
32 
33 #include "adb.h"
34 #include "adb_auth.h"
35 #include "adb_client.h"
36 #include "adb_listeners.h"
37 #include "adb_mdns.h"
38 #include "adb_utils.h"
39 #include "adb_wifi.h"
40 #include "client/usb.h"
41 #include "commandline.h"
42 #include "sysdeps/chrono.h"
43 #include "transport.h"
44 
45 const char** __adb_argv;
46 const char** __adb_envp;
47 
48 static void setup_daemon_logging() {
49     const std::string log_file_path(GetLogFilePath());
50     int fd = unix_open(log_file_path, O_WRONLY | O_CREAT | O_APPEND, 0640);
51     if (fd == -1) {
52         PLOG(FATAL) << "cannot open " << log_file_path;
53     }
54     if (dup2(fd, STDOUT_FILENO) == -1) {
55         PLOG(FATAL) << "cannot redirect stdout";
56     }
57     if (dup2(fd, STDERR_FILENO) == -1) {
58         PLOG(FATAL) << "cannot redirect stderr";
59     }
60     unix_close(fd);
61 
62     fprintf(stderr, "--- adb starting (pid %d) ---\n", getpid());
63     LOG(INFO) << adb_version();
64 }
65 
66 void adb_server_cleanup() {
67     // Upon exit, we want to clean up in the following order:
68     //   1. close_smartsockets, so that we don't get any new clients
69     //   2. kick_all_transports, to avoid writing only part of a packet to a transport.
70     //   3. usb_cleanup, to tear down the USB stack.
71     //   4. mdns_cleanup, to tear down mdns stack.
72     close_smartsockets();
73     kick_all_transports();
74     usb_cleanup();
75     mdns_cleanup();
76 }
77 
78 static void intentionally_leak() {
79     void* p = ::operator new(1);
80     // The analyzer is upset about this leaking. NOLINTNEXTLINE
81     LOG(INFO) << "leaking pointer " << p;
82 }
83 
84 int adb_server_main(int is_daemon, const std::string& socket_spec, int ack_reply_fd) {
85 #if defined(_WIN32)
86     // adb start-server starts us up with stdout and stderr hooked up to
87     // anonymous pipes. When the C Runtime sees this, it makes stderr and
88     // stdout buffered, but to improve the chance that error output is seen,
89     // unbuffer stdout and stderr just like if we were run at the console.
90     // This also keeps stderr unbuffered when it is redirected to adb.log.
91     if (is_daemon) {
92         if (setvbuf(stdout, nullptr, _IONBF, 0) == -1) {
93             PLOG(FATAL) << "cannot make stdout unbuffered";
94         }
95         if (setvbuf(stderr, nullptr, _IONBF, 0) == -1) {
96             PLOG(FATAL) << "cannot make stderr unbuffered";
97         }
98     }
99 
100     // TODO: On Ctrl-C, consider trying to kill a starting up adb server (if we're in
101     // launch_server) by calling GenerateConsoleCtrlEvent().
102 
103     // On Windows, SIGBREAK is when Ctrl-Break is pressed or the console window is closed. It should
104     // act like Ctrl-C.
105     signal(SIGBREAK, [](int) { raise(SIGINT); });
106 #endif
107     signal(SIGINT, [](int) {
108         fdevent_run_on_main_thread([]() { exit(0); });
109     });
110 
111     const char* reject_kill_server = getenv("ADB_REJECT_KILL_SERVER");
112     if (reject_kill_server && strcmp(reject_kill_server, "1") == 0) {
113         adb_set_reject_kill_server(true);
114     }
115 
116     const char* leak = getenv("ADB_LEAK");
117     if (leak && strcmp(leak, "1") == 0) {
118         intentionally_leak();
119     }
120 
121     if (is_daemon) {
122         close_stdin();
123         setup_daemon_logging();
124     }
125 
126     atexit(adb_server_cleanup);
127 
128     init_transport_registration();
129     init_reconnect_handler();
130 
131     adb_wifi_init();
132     if (!getenv("ADB_MDNS") || strcmp(getenv("ADB_MDNS"), "0") != 0) {
133         init_mdns_transport_discovery();
134     }
135 
136     if (!getenv("ADB_USB") || strcmp(getenv("ADB_USB"), "0") != 0) {
137         if (should_use_libusb()) {
138             libusb::usb_init();
139         } else {
140             usb_init();
141         }
142     } else {
143         adb_notify_device_scan_complete();
144     }
145 
146     if (!getenv("ADB_EMU") || strcmp(getenv("ADB_EMU"), "0") != 0) {
147         local_init(android::base::StringPrintf("tcp:%d", DEFAULT_ADB_LOCAL_TRANSPORT_PORT));
148     }
149 
150     std::string error;
151 
152     auto start = std::chrono::steady_clock::now();
153 
154     // If we told a previous adb server to quit because of version mismatch, we can get to this
155     // point before it's finished exiting. Retry for a while to give it some time. Don't actually
156     // accept any connections until adb_wait_for_device_initialization finishes below.
157     while (install_listener(socket_spec, "*smartsocket*", nullptr, INSTALL_LISTENER_DISABLED,
158                             nullptr, &error) != INSTALL_STATUS_OK) {
159         if (std::chrono::steady_clock::now() - start > 0.5s) {
160             LOG(FATAL) << "could not install *smartsocket* listener: " << error;
161         }
162 
163         std::this_thread::sleep_for(100ms);
164     }
165 
166     adb_auth_init();
167 
168     if (is_daemon) {
169 #if !defined(_WIN32)
170         // Start a new session for the daemon. Do this here instead of after the fork so
171         // that a ctrl-c between the "starting server" and "done starting server" messages
172         // gets a chance to terminate the server.
173         // setsid will fail with EPERM if it's already been a lead process of new session.
174         // Ignore such error.
175         if (setsid() == -1 && errno != EPERM) {
176             PLOG(FATAL) << "setsid() failed";
177         }
178 #endif
179     }
180 
181     // Wait for the USB scan to complete before notifying the parent that we're up.
182     // We need to perform this in a thread, because we would otherwise block the event loop.
183     std::thread notify_thread([ack_reply_fd]() {
184         adb_wait_for_device_initialization();
185 
186         if (ack_reply_fd >= 0) {
187             // Any error output written to stderr now goes to adb.log. We could
188             // keep around a copy of the stderr fd and use that to write any errors
189             // encountered by the following code, but that is probably overkill.
190 #if defined(_WIN32)
191             const HANDLE ack_reply_handle = cast_int_to_handle(ack_reply_fd);
192             const CHAR ack[] = "OK\n";
193             const DWORD bytes_to_write = arraysize(ack) - 1;
194             DWORD written = 0;
195             if (!WriteFile(ack_reply_handle, ack, bytes_to_write, &written, NULL)) {
196                 LOG(FATAL) << "cannot write ACK to handle " << ack_reply_handle
197                            << android::base::SystemErrorCodeToString(GetLastError());
198             }
199             if (written != bytes_to_write) {
200                 LOG(FATAL) << "cannot write " << bytes_to_write << " bytes of ACK: only wrote "
201                            << written << " bytes";
202             }
203             CloseHandle(ack_reply_handle);
204 #else
205             // TODO(danalbert): Can't use SendOkay because we're sending "OK\n", not
206             // "OKAY".
207             if (!android::base::WriteStringToFd("OK\n", ack_reply_fd)) {
208                 PLOG(FATAL) << "error writing ACK to fd " << ack_reply_fd;
209             }
210             unix_close(ack_reply_fd);
211 #endif
212         }
213         // We don't accept() client connections until this point: this way, clients
214         // can't see wonky state early in startup even if they're connecting directly
215         // to the server instead of going through the adb program.
216         fdevent_run_on_main_thread([] { enable_server_sockets(); });
217     });
218     notify_thread.detach();
219 
220 #if defined(__linux__)
221     // Write our location to .android/adb.$PORT, so that older clients can exec us.
222     std::string path;
223     if (!android::base::Readlink("/proc/self/exe", &path)) {
224         PLOG(ERROR) << "failed to readlink /proc/self/exe";
225     }
226 
227     std::optional<std::string> server_executable_path = adb_get_server_executable_path();
228     if (server_executable_path) {
229       if (!android::base::WriteStringToFile(path, *server_executable_path)) {
230           PLOG(ERROR) << "failed to write server path to " << path;
231       }
232     }
233 #endif
234 
235     D("Event loop starting");
236     fdevent_loop();
237     return 0;
238 }
239 
240 int main(int argc, char* argv[], char* envp[]) {
241     __adb_argv = const_cast<const char**>(argv);
242     __adb_envp = const_cast<const char**>(envp);
243     adb_trace_init(argv);
244     return adb_commandline(argc - 1, const_cast<const char**>(argv + 1));
245 }
246