components/nacl/loader/nacl_ipc_adapter.h

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CHROME_NACL_NACL_IPC_ADAPTER_H_
   6 #define CHROME_NACL_NACL_IPC_ADAPTER_H_
   7
   8 #include <map>
   9 #include <queue>
  10 #include <string>
  11 #include <vector>
  12
  13 #include "base/basictypes.h"
  14 #include "base/callback.h"
  15 #include "base/files/scoped_file.h"
  16 #include "base/memory/ref_counted.h"
  17 #include "base/memory/scoped_ptr.h"
  18 #include "base/memory/scoped_vector.h"
  19 #include "base/memory/shared_memory.h"
  20 #include "base/pickle.h"
  21 #include "base/synchronization/condition_variable.h"
  22 #include "base/synchronization/lock.h"
  23 #include "base/task_runner.h"
  24 #include "ipc/ipc_listener.h"
  25 #include "ipc/ipc_platform_file.h"
  26 #include "ppapi/c/pp_stdint.h"
  27 #include "ppapi/proxy/nacl_message_scanner.h"
  28
  29 struct NaClDesc;
  30 struct NaClImcTypedMsgHdr;
  31 struct PP_Size;
  32
  33 namespace IPC {
  34 class Channel;
  35 struct ChannelHandle;
  36 }
  37
  38 namespace ppapi {
  39 class HostResource;
  40 }
  41
  42 // Adapts a Chrome IPC channel to an IPC channel that we expose to Native
  43 // Client. This provides a mapping in both directions, so when IPC messages
  44 // come in from another process, we rewrite them and allow them to be received
  45 // via a recvmsg-like interface in the NaCl code. When NaCl code calls sendmsg,
  46 // we implement that as sending IPC messages on the channel.
  47 //
  48 // This object also provides the necessary logic for rewriting IPC messages.
  49 // NaCl code is platform-independent and runs in a Posix-like enviroment, but
  50 // some formatting in the message and the way handles are transferred varies
  51 // by platform. This class bridges that gap to provide what looks like a
  52 // normal platform-specific IPC implementation to Chrome, and a Posix-like
  53 // version on every platform to NaCl.
  54 //
  55 // This object must be threadsafe since the nacl environment determines which
  56 // thread every function is called on.
  57 class NaClIPCAdapter : public base::RefCountedThreadSafe<NaClIPCAdapter>,
  58                        public IPC::Listener {
  59  public:
  60   // Chrome's IPC message format varies by platform, NaCl's does not. In
  61   // particular, the header has some extra fields on Posix platforms. Since
  62   // NaCl is a Posix environment, it gets that version of the header. This
  63   // header is duplicated here so we have a cross-platform definition of the
  64   // header we're exposing to NaCl.
  65 #pragma pack(push, 4)
  66   struct NaClMessageHeader : public Pickle::Header {
  67     int32 routing;
  68     uint32 type;
  69     uint32 flags;
  70     uint16 num_fds;
  71     uint16 pad;
  72   };
  73 #pragma pack(pop)
  74
  75   // Creates an adapter, using the thread associated with the given task
  76   // runner for posting messages. In normal use, the task runner will post to
  77   // the I/O thread of the process.
  78   //
  79   // If you use this constructor, you MUST call ConnectChannel after the
  80   // NaClIPCAdapter is constructed, or the NaClIPCAdapter's channel will not be
  81   // connected.
  82   NaClIPCAdapter(const IPC::ChannelHandle& handle, base::TaskRunner* runner);
  83
  84   // Initializes with a given channel that's already created for testing
  85   // purposes. This function will take ownership of the given channel.
  86   NaClIPCAdapter(scoped_ptr<IPC::Channel> channel, base::TaskRunner* runner);
  87
  88   // Connect the channel. This must be called after the constructor that accepts
  89   // an IPC::ChannelHandle, and causes the Channel to be connected on the IO
  90   // thread.
  91   void ConnectChannel();
  92
  93   // Implementation of sendmsg. Returns the number of bytes written or -1 on
  94   // failure.
  95   int Send(const NaClImcTypedMsgHdr* msg);
  96
  97   // Implementation of recvmsg. Returns the number of bytes read or -1 on
  98   // failure. This will block until there's an error or there is data to
  99   // read.
 100   int BlockingReceive(NaClImcTypedMsgHdr* msg);
 101
 102   // Closes the IPC channel.
 103   void CloseChannel();
 104
 105   // Make a NaClDesc that refers to this NaClIPCAdapter. Note that the returned
 106   // NaClDesc is reference-counted, and a reference is returned.
 107   NaClDesc* MakeNaClDesc();
 108
 109 #if defined(OS_POSIX)
 110   base::ScopedFD TakeClientFileDescriptor();
 111 #endif
 112
 113   // Listener implementation.
 114   bool OnMessageReceived(const IPC::Message& message) override;
 115   void OnChannelConnected(int32 peer_pid) override;
 116   void OnChannelError() override;
 117
 118   typedef base::Callback<void(IPC::PlatformFileForTransit, base::FilePath)>
 119       ResolveFileTokenReplyCallback;
 120
 121   typedef base::Callback<void(uint64_t,  // file_token_lo
 122                               uint64_t,  // file_token_hi
 123                               ResolveFileTokenReplyCallback)>
 124       ResolveFileTokenCallback;
 125
 126   // Sets a callback to be invoked for resolving file tokens received from the
 127   // renderer. When the file token is resolved, the
 128   // ResolveFileTokenReplyCallback passed inside the ResolveFileTokenCallback
 129   // will be invoked.
 130   void set_resolve_file_token_callback(ResolveFileTokenCallback cb) {
 131     resolve_file_token_cb_ = cb;
 132   }
 133
 134  private:
 135   friend class base::RefCountedThreadSafe<NaClIPCAdapter>;
 136
 137   class RewrittenMessage;
 138
 139   // This is the data that must only be accessed inside the lock. This struct
 140   // just separates it so it's easier to see.
 141   struct LockedData {
 142     LockedData();
 143     ~LockedData();
 144
 145     // Messages that we have read off of the Chrome IPC channel that are waiting
 146     // to be received by the plugin.
 147     std::queue< scoped_refptr<RewrittenMessage> > to_be_received_;
 148
 149     ppapi::proxy::NaClMessageScanner nacl_msg_scanner_;
 150
 151     // Data that we've queued from the plugin to send, but doesn't consist of a
 152     // full message yet. The calling code can break apart the message into
 153     // smaller pieces, and we need to send the message to the other process in
 154     // one chunk.
 155     //
 156     // The IPC channel always starts a new send() at the beginning of each
 157     // message, so we don't need to worry about arbitrary message boundaries.
 158     std::string to_be_sent_;
 159
 160     bool channel_closed_;
 161   };
 162
 163   // This is the data that must only be accessed on the I/O thread (as defined
 164   // by TaskRunner). This struct just separates it so it's easier to see.
 165   struct IOThreadData {
 166     IOThreadData();
 167     ~IOThreadData();
 168
 169     scoped_ptr<IPC::Channel> channel_;
 170
 171     // When we send a synchronous message (from untrusted to trusted), we store
 172     // its type here, so that later we can associate the reply with its type
 173     // for scanning.
 174     typedef std::map<int, uint32> PendingSyncMsgMap;
 175     PendingSyncMsgMap pending_sync_msgs_;
 176   };
 177
 178   ~NaClIPCAdapter() override;
 179
 180   void OnFileTokenResolved(const IPC::Message& orig_msg,
 181                            IPC::PlatformFileForTransit ipc_fd,
 182                            base::FilePath file_path);
 183
 184   bool RewriteMessage(const IPC::Message& msg, uint32_t type);
 185
 186   // Returns 0 if nothing is waiting.
 187   int LockedReceive(NaClImcTypedMsgHdr* msg);
 188
 189   // Sends a message that we know has been completed to the Chrome process.
 190   bool SendCompleteMessage(const char* buffer, size_t buffer_len);
 191
 192   // Clears the LockedData.to_be_sent_ structure in a way to make sure that
 193   // the memory is deleted. std::string can sometimes hold onto the buffer
 194   // for future use which we don't want.
 195   void ClearToBeSent();
 196
 197   void ConnectChannelOnIOThread();
 198   void CloseChannelOnIOThread();
 199   void SendMessageOnIOThread(scoped_ptr<IPC::Message> message);
 200
 201   // Saves the message to forward to NaCl. This method assumes that the caller
 202   // holds the lock for locked_data_.
 203   void SaveMessage(const IPC::Message& message,
 204                    RewrittenMessage* rewritten_message);
 205
 206   base::Lock lock_;
 207   base::ConditionVariable cond_var_;
 208
 209   scoped_refptr<base::TaskRunner> task_runner_;
 210
 211   ResolveFileTokenCallback resolve_file_token_cb_;
 212
 213   // To be accessed inside of lock_ only.
 214   LockedData locked_data_;
 215
 216   // To be accessed on the I/O thread (via task runner) only.
 217   IOThreadData io_thread_data_;
 218
 219   DISALLOW_COPY_AND_ASSIGN(NaClIPCAdapter);
 220 };
 221
 222 // Export TranslatePepperFileReadWriteOpenFlags for testing.
 223 int TranslatePepperFileReadWriteOpenFlagsForTesting(int32_t pp_open_flags);
 224
 225 #endif  // CHROME_NACL_NACL_IPC_ADAPTER_H_