/* * Copyright (C) 2015 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #define TRACE_TAG RWX #include "adb_io.h" #include <unistd.h> #include <thread> #include <android-base/stringprintf.h> #include "adb.h" #include "adb_trace.h" #include "adb_utils.h" #include "sysdeps.h" bool SendProtocolString(int fd, const std::string& s) { unsigned int length = s.size(); if (length > MAX_PAYLOAD - 4) { errno = EMSGSIZE; return false; } // The cost of sending two strings outweighs the cost of formatting. // "adb sync" performance is affected by this. return WriteFdFmt(fd, "%04x%.*s", length, length, s.c_str()); } bool ReadProtocolString(int fd, std::string* s, std::string* error) { char buf[5]; if (!ReadFdExactly(fd, buf, 4)) { *error = perror_str("protocol fault (couldn't read status length)"); return false; } buf[4] = 0; unsigned long len = strtoul(buf, 0, 16); s->resize(len, '\0'); if (!ReadFdExactly(fd, &(*s)[0], len)) { *error = perror_str("protocol fault (couldn't read status message)"); return false; } return true; } bool SendOkay(int fd) { return WriteFdExactly(fd, "OKAY", 4); } bool SendFail(int fd, const std::string& reason) { return WriteFdExactly(fd, "FAIL", 4) && SendProtocolString(fd, reason); } bool ReadFdExactly(int fd, void* buf, size_t len) { char* p = reinterpret_cast<char*>(buf); size_t len0 = len; D("readx: fd=%d wanted=%zu", fd, len); while (len > 0) { int r = adb_read(fd, p, len); if (r > 0) { len -= r; p += r; } else if (r == -1) { D("readx: fd=%d error %d: %s", fd, errno, strerror(errno)); return false; } else { D("readx: fd=%d disconnected", fd); errno = 0; return false; } } VLOG(RWX) << "readx: fd=" << fd << " wanted=" << len0 << " got=" << (len0 - len) << " " << dump_hex(reinterpret_cast<const unsigned char*>(buf), len0); return true; } bool WriteFdExactly(int fd, const void* buf, size_t len) { const char* p = reinterpret_cast<const char*>(buf); int r; VLOG(RWX) << "writex: fd=" << fd << " len=" << len << " " << dump_hex(reinterpret_cast<const unsigned char*>(buf), len); while (len > 0) { r = adb_write(fd, p, len); if (r == -1) { D("writex: fd=%d error %d: %s", fd, errno, strerror(errno)); if (errno == EAGAIN) { std::this_thread::yield(); continue; } else if (errno == EPIPE) { D("writex: fd=%d disconnected", fd); errno = 0; return false; } else { return false; } } else { len -= r; p += r; } } return true; } bool WriteFdExactly(int fd, const char* str) { return WriteFdExactly(fd, str, strlen(str)); } bool WriteFdExactly(int fd, const std::string& str) { return WriteFdExactly(fd, str.c_str(), str.size()); } bool WriteFdFmt(int fd, const char* fmt, ...) { std::string str; va_list ap; va_start(ap, fmt); android::base::StringAppendV(&str, fmt, ap); va_end(ap); return WriteFdExactly(fd, str); } bool ReadOrderlyShutdown(int fd) { char buf[16]; // Only call this function if you're sure that the peer does // orderly/graceful shutdown of the socket, closing the socket so that // adb_read() will return 0. If the peer keeps the socket open, adb_read() // will never return. int result = adb_read(fd, buf, sizeof(buf)); if (result == -1) { // If errno is EAGAIN, that means this function was called on a // nonblocking socket and it would have blocked (which would be bad // because we'd probably block the main thread where nonblocking IO is // done). Don't do that. If you have a nonblocking socket, use the // fdevent APIs to get called on FDE_READ, and then call this function // if you really need to, but it shouldn't be needed for server sockets. CHECK_NE(errno, EAGAIN); // Note that on Windows, orderly shutdown sometimes causes // recv() == SOCKET_ERROR && WSAGetLastError() == WSAECONNRESET. That // can be ignored. return false; } else if (result == 0) { // Peer has performed an orderly/graceful shutdown. return true; } else { // Unexpectedly received data. This is essentially a protocol error // because you should not call this function unless you expect no more // data. We don't repeatedly call adb_read() until we get zero because // we don't know how long that would take, but we do know that the // caller wants to close the socket soon. VLOG(RWX) << "ReadOrderlyShutdown(" << fd << ") unexpectedly read " << dump_hex(buf, result); // Shutdown the socket to prevent the caller from reading or writing to // it which doesn't make sense if we just read and discarded some data. adb_shutdown(fd); errno = EINVAL; return false; } }