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      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 #ifndef ADB_IO_H
     18 #define ADB_IO_H
     19 
     20 #include <sys/types.h>
     21 
     22 #include <string>
     23 
     24 // Sends the protocol "OKAY" message.
     25 bool SendOkay(int fd);
     26 
     27 // Sends the protocol "FAIL" message, with the given failure reason.
     28 bool SendFail(int fd, const std::string& reason);
     29 
     30 // Writes a protocol-format string; a four hex digit length followed by the string data.
     31 bool SendProtocolString(int fd, const std::string& s);
     32 
     33 // Reads a protocol-format string; a four hex digit length followed by the string data.
     34 bool ReadProtocolString(int fd, std::string* s, std::string* error);
     35 
     36 // Reads exactly len bytes from fd into buf.
     37 //
     38 // Returns false if there is an error or if EOF was reached before len bytes
     39 // were read. If EOF was found, errno will be set to 0.
     40 //
     41 // If this function fails, the contents of buf are undefined.
     42 bool ReadFdExactly(int fd, void* buf, size_t len);
     43 
     44 // Given a client socket, wait for orderly/graceful shutdown. Call this:
     45 //
     46 // * Before closing a client socket.
     47 // * Only when no more data is expected to come in.
     48 // * Only when the server is not waiting for data from the client (because then
     49 //   the client and server will deadlock waiting for each other).
     50 // * Only when the server is expected to close its socket right now.
     51 // * Don't call shutdown(SHUT_WR) before calling this because that will shutdown
     52 //   the client socket early, defeating the purpose of calling this.
     53 //
     54 // Waiting for orderly/graceful shutdown of the server socket will cause the
     55 // server socket to close before the client socket. That prevents the client
     56 // socket from staying in TIME_WAIT which eventually causes subsequent
     57 // connect()s from the client to fail with WSAEADDRINUSE on Windows.
     58 // Returns true if it is sure that orderly/graceful shutdown has occurred with
     59 // no additional data read from the server.
     60 bool ReadOrderlyShutdown(int fd);
     61 
     62 // Writes exactly len bytes from buf to fd.
     63 //
     64 // Returns false if there is an error or if the fd was closed before the write
     65 // completed. If the other end of the fd (such as in a socket, pipe, or fifo),
     66 // is closed, errno will be set to 0.
     67 bool WriteFdExactly(int fd, const void* buf, size_t len);
     68 
     69 // Same as above, but for strings.
     70 bool WriteFdExactly(int fd, const char* s);
     71 bool WriteFdExactly(int fd, const std::string& s);
     72 
     73 // Same as above, but formats the string to send.
     74 bool WriteFdFmt(int fd, const char* fmt, ...) __attribute__((__format__(__printf__, 2, 3)));
     75 
     76 #endif /* ADB_IO_H */
     77