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 RWX
18
19 #include "adb_io.h"
20
21 #include <unistd.h>
22
23 #if !ADB_HOST
24 #include <sys/socket.h>
25 #include <sys/un.h>
26 #endif
27
28 #include <thread>
29
30 #include <android-base/stringprintf.h>
31
32 #include "adb.h"
33 #include "adb_trace.h"
34 #include "adb_utils.h"
35 #include "sysdeps.h"
36
SendProtocolString(int fd,std::string_view s)37 bool SendProtocolString(int fd, std::string_view s) {
38 unsigned int length = s.size();
39 if (length > MAX_PAYLOAD - 4) {
40 errno = EMSGSIZE;
41 return false;
42 }
43
44 // The cost of sending two strings outweighs the cost of formatting.
45 // "adb sync" performance is affected by this.
46 auto str = android::base::StringPrintf("%04x", length).append(s);
47 return WriteFdExactly(fd, str);
48 }
49
ReadProtocolString(int fd,std::string * s,std::string * error)50 bool ReadProtocolString(int fd, std::string* s, std::string* error) {
51 char buf[5];
52 if (!ReadFdExactly(fd, buf, 4)) {
53 *error = perror_str("protocol fault (couldn't read status length)");
54 return false;
55 }
56 buf[4] = 0;
57
58 unsigned long len = strtoul(buf, nullptr, 16);
59 s->resize(len, '\0');
60 if (!ReadFdExactly(fd, &(*s)[0], len)) {
61 *error = perror_str("protocol fault (couldn't read status message)");
62 return false;
63 }
64
65 return true;
66 }
67
SendOkay(int fd)68 bool SendOkay(int fd) {
69 return WriteFdExactly(fd, "OKAY", 4);
70 }
71
SendFail(int fd,std::string_view reason)72 bool SendFail(int fd, std::string_view reason) {
73 return WriteFdExactly(fd, "FAIL", 4) && SendProtocolString(fd, reason);
74 }
75
ReadFdExactly(int fd,void * buf,size_t len)76 bool ReadFdExactly(int fd, void* buf, size_t len) {
77 char* p = reinterpret_cast<char*>(buf);
78
79 size_t len0 = len;
80
81 D("readx: fd=%d wanted=%zu", fd, len);
82 while (len > 0) {
83 int r = adb_read(fd, p, len);
84 if (r > 0) {
85 len -= r;
86 p += r;
87 } else if (r == -1) {
88 D("readx: fd=%d error %d: %s", fd, errno, strerror(errno));
89 return false;
90 } else {
91 D("readx: fd=%d disconnected", fd);
92 errno = 0;
93 return false;
94 }
95 }
96
97 VLOG(RWX) << "readx: fd=" << fd << " wanted=" << len0 << " got=" << (len0 - len)
98 << " " << dump_hex(reinterpret_cast<const unsigned char*>(buf), len0);
99
100 return true;
101 }
102
WriteFdExactly(int fd,const void * buf,size_t len)103 bool WriteFdExactly(int fd, const void* buf, size_t len) {
104 const char* p = reinterpret_cast<const char*>(buf);
105 int r;
106
107 VLOG(RWX) << "writex: fd=" << fd << " len=" << len
108 << " " << dump_hex(reinterpret_cast<const unsigned char*>(buf), len);
109
110 while (len > 0) {
111 r = adb_write(fd, p, len);
112 if (r == -1) {
113 D("writex: fd=%d error %d: %s", fd, errno, strerror(errno));
114 if (errno == EAGAIN) {
115 std::this_thread::yield();
116 continue;
117 } else if (errno == EPIPE) {
118 D("writex: fd=%d disconnected", fd);
119 errno = 0;
120 return false;
121 } else {
122 return false;
123 }
124 } else {
125 len -= r;
126 p += r;
127 }
128 }
129 return true;
130 }
131
WriteFdExactly(int fd,const char * str)132 bool WriteFdExactly(int fd, const char* str) {
133 return WriteFdExactly(fd, str, strlen(str));
134 }
135
WriteFdExactly(int fd,const std::string & str)136 bool WriteFdExactly(int fd, const std::string& str) {
137 return WriteFdExactly(fd, str.c_str(), str.size());
138 }
139
WriteFdFmt(int fd,const char * fmt,...)140 bool WriteFdFmt(int fd, const char* fmt, ...) {
141 std::string str;
142
143 va_list ap;
144 va_start(ap, fmt);
145 android::base::StringAppendV(&str, fmt, ap);
146 va_end(ap);
147
148 return WriteFdExactly(fd, str);
149 }
150
ReadOrderlyShutdown(int fd)151 bool ReadOrderlyShutdown(int fd) {
152 char buf[16];
153
154 // Only call this function if you're sure that the peer does
155 // orderly/graceful shutdown of the socket, closing the socket so that
156 // adb_read() will return 0. If the peer keeps the socket open, adb_read()
157 // will never return.
158 int result = adb_read(fd, buf, sizeof(buf));
159 if (result == -1) {
160 // If errno is EAGAIN, that means this function was called on a
161 // nonblocking socket and it would have blocked (which would be bad
162 // because we'd probably block the main thread where nonblocking IO is
163 // done). Don't do that. If you have a nonblocking socket, use the
164 // fdevent APIs to get called on FDE_READ, and then call this function
165 // if you really need to, but it shouldn't be needed for server sockets.
166 CHECK_NE(errno, EAGAIN);
167
168 // Note that on Windows, orderly shutdown sometimes causes
169 // recv() == SOCKET_ERROR && WSAGetLastError() == WSAECONNRESET. That
170 // can be ignored.
171 return false;
172 } else if (result == 0) {
173 // Peer has performed an orderly/graceful shutdown.
174 return true;
175 } else {
176 // Unexpectedly received data. This is essentially a protocol error
177 // because you should not call this function unless you expect no more
178 // data. We don't repeatedly call adb_read() until we get zero because
179 // we don't know how long that would take, but we do know that the
180 // caller wants to close the socket soon.
181 VLOG(RWX) << "ReadOrderlyShutdown(" << fd << ") unexpectedly read "
182 << dump_hex(buf, result);
183 // Shutdown the socket to prevent the caller from reading or writing to
184 // it which doesn't make sense if we just read and discarded some data.
185 adb_shutdown(fd);
186 errno = EINVAL;
187 return false;
188 }
189 }
190