Home | History | Annotate | Download | only in dt_fd_forward
      1 /* Copyright (C) 2017 The Android Open Source Project
      2  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
      3  *
      4  * This file implements interfaces from the file jdwpTransport.h. This implementation
      5  * is licensed under the same terms as the file jdwpTransport.h.  The
      6  * copyright and license information for the file jdwpTranport.h follows.
      7  *
      8  * Copyright (c) 2003, 2016, Oracle and/or its affiliates. All rights reserved.
      9  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
     10  *
     11  * This code is free software; you can redistribute it and/or modify it
     12  * under the terms of the GNU General Public License version 2 only, as
     13  * published by the Free Software Foundation.  Oracle designates this
     14  * particular file as subject to the "Classpath" exception as provided
     15  * by Oracle in the LICENSE file that accompanied this code.
     16  *
     17  * This code is distributed in the hope that it will be useful, but WITHOUT
     18  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
     19  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
     20  * version 2 for more details (a copy is included in the LICENSE file that
     21  * accompanied this code).
     22  *
     23  * You should have received a copy of the GNU General Public License version
     24  * 2 along with this work; if not, write to the Free Software Foundation,
     25  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
     26  *
     27  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
     28  * or visit www.oracle.com if you need additional information or have any
     29  * questions.
     30  */
     31 
     32 #ifndef ART_DT_FD_FORWARD_DT_FD_FORWARD_H_
     33 #define ART_DT_FD_FORWARD_DT_FD_FORWARD_H_
     34 
     35 #include <atomic>
     36 #include <condition_variable>
     37 #include <mutex>
     38 #include <string>
     39 
     40 #include <android-base/logging.h>
     41 #include <android-base/thread_annotations.h>
     42 #include <android-base/unique_fd.h>
     43 
     44 #include <arpa/inet.h>
     45 #include <sys/eventfd.h>
     46 #include <unistd.h>
     47 #include <poll.h>
     48 
     49 #include <jni.h>
     50 #include <jvmti.h>
     51 #include <jdwpTransport.h>
     52 
     53 #include "fd_transport.h"
     54 
     55 namespace dt_fd_forward {
     56 
     57 static constexpr uint8_t kReplyFlag = 0x80;
     58 // Macro and constexpr to make error values less annoying to write.
     59 #define ERR(e) JDWPTRANSPORT_ERROR_ ## e
     60 static constexpr jdwpTransportError OK = ERR(NONE);
     61 
     62 static constexpr const char kJdwpHandshake[14] = {
     63     'J', 'D', 'W', 'P', '-', 'H', 'a', 'n', 'd', 's', 'h', 'a', 'k', 'e'
     64 };  // "JDWP-Handshake"
     65 
     66 enum class TransportState {
     67   kClosed,       // Main state.
     68   kListenSetup,  // Transient, wait for the state to change before proceeding.
     69   kListening,    // Main state.
     70   kOpening,      // Transient, wait for the state to change before proceeding.
     71   kOpen,         // Main state.
     72 };
     73 
     74 enum class IOResult {
     75   kOk, kInterrupt, kError, kEOF,
     76 };
     77 
     78 class PacketReader;
     79 class PacketWriter;
     80 
     81 // TODO It would be good to get the thread-safety analysis checks working but first we would need to
     82 // use something other than std::mutex which does not have the annotations required.
     83 class FdForwardTransport : public jdwpTransportEnv {
     84  public:
     85   explicit FdForwardTransport(jdwpTransportCallback* cb);
     86   ~FdForwardTransport();
     87 
     88   jdwpTransportError PerformAttach(int listen_fd);
     89   jdwpTransportError SetupListen(int listen_fd);
     90   jdwpTransportError StopListening();
     91 
     92   jboolean IsOpen();
     93 
     94   jdwpTransportError WritePacket(const jdwpPacket* pkt);
     95   jdwpTransportError ReadPacket(jdwpPacket* pkt);
     96   jdwpTransportError Close();
     97   jdwpTransportError Accept();
     98   jdwpTransportError GetLastError(/*out*/char** description);
     99 
    100   void* Alloc(size_t data);
    101   void Free(void* data);
    102 
    103  private:
    104   void SetLastError(const std::string& desc);
    105 
    106   bool ChangeState(TransportState old_state, TransportState new_state);  // REQUIRES(state_mutex_);
    107 
    108   // Gets the fds from the server side. do_handshake returns whether the transport can skip the
    109   // jdwp handshake.
    110   IOResult ReceiveFdsFromSocket(/*out*/bool* do_handshake);
    111 
    112   IOResult WriteFully(const void* data, size_t ndata);  // REQUIRES(!state_mutex_);
    113   IOResult WriteFullyWithoutChecks(const void* data, size_t ndata);  // REQUIRES(state_mutex_);
    114   IOResult ReadFully(void* data, size_t ndata);  // REQUIRES(!state_mutex_);
    115   IOResult ReadUpToMax(void* data, size_t ndata, /*out*/size_t* amount_read);
    116       // REQUIRES(state_mutex_);
    117   IOResult ReadFullyWithoutChecks(void* data, size_t ndata);  // REQUIRES(state_mutex_);
    118 
    119   void CloseFdsLocked();  // REQUIRES(state_mutex_)
    120 
    121   // The allocation/deallocation functions.
    122   jdwpTransportCallback mem_;
    123 
    124   // Input from the server;
    125   android::base::unique_fd read_fd_;  // GUARDED_BY(state_mutex_);
    126   // Output to the server;
    127   android::base::unique_fd write_fd_;  // GUARDED_BY(state_mutex_);
    128 
    129   // an eventfd passed with the write_fd to the transport that we will 'read' from to get a lock on
    130   // the write_fd_. The other side must not hold it for unbounded time.
    131   android::base::unique_fd write_lock_fd_;  // GUARDED_BY(state_mutex_);
    132 
    133   // Eventfd we will use to wake-up paused reads for close().
    134   android::base::unique_fd wakeup_fd_;
    135 
    136   // Socket we will get the read/write fd's from.
    137   android::base::unique_fd listen_fd_;
    138 
    139   // Fd we will write close notification to. This is a dup of listen_fd_.
    140   android::base::unique_fd close_notify_fd_;
    141 
    142   TransportState state_;  // GUARDED_BY(state_mutex_);
    143 
    144   std::mutex state_mutex_;
    145   std::condition_variable state_cv_;
    146 
    147   // A counter that we use to make sure we don't do half a read on one and half on another fd.
    148   std::atomic<uint64_t> current_seq_num_;
    149 
    150   friend class PacketReader;  // For ReadFullyWithInterrupt
    151   friend class PacketWriter;  // For WriteFullyWithInterrupt
    152 };
    153 
    154 }  // namespace dt_fd_forward
    155 
    156 #endif  // ART_DT_FD_FORWARD_DT_FD_FORWARD_H_
    157