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 COMPONENTS_NACL_LOADER_NACL_IPC_ADAPTER_H_
   6 #define COMPONENTS_NACL_LOADER_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/pickle.h"
  19 #include "base/synchronization/condition_variable.h"
  20 #include "base/synchronization/lock.h"
  21 #include "base/task_runner.h"
  22 #include "ipc/ipc_listener.h"
  23 #include "ipc/ipc_platform_file.h"
  24 #include "ppapi/c/pp_stdint.h"
  25 #include "ppapi/proxy/nacl_message_scanner.h"
  26
  27 struct NaClDesc;
  28 struct NaClImcTypedMsgHdr;
  29 struct PP_Size;
  30
  31 namespace IPC {
  32 class Channel;
  33 struct ChannelHandle;
  34 }
  35
  36 namespace ppapi {
  37 class HostResource;
  38 }
  39
  40 // Adapts a Chrome IPC channel to an IPC channel that we expose to Native
  41 // Client. This provides a mapping in both directions, so when IPC messages
  42 // come in from another process, we rewrite them and allow them to be received
  43 // via a recvmsg-like interface in the NaCl code. When NaCl code calls sendmsg,
  44 // we implement that as sending IPC messages on the channel.
  45 //
  46 // This object also provides the necessary logic for rewriting IPC messages.
  47 // NaCl code is platform-independent and runs in a Posix-like enviroment, but
  48 // some formatting in the message and the way handles are transferred varies
  49 // by platform. This class bridges that gap to provide what looks like a
  50 // normal platform-specific IPC implementation to Chrome, and a Posix-like
  51 // version on every platform to NaCl.
  52 //
  53 // This object must be threadsafe since the nacl environment determines which
  54 // thread every function is called on.
  55 class NaClIPCAdapter : public base::RefCountedThreadSafe<NaClIPCAdapter>,
  56                        public IPC::Listener {
  57  public:
  58   // Chrome's IPC message format varies by platform, NaCl's does not. In
  59   // particular, the header has some extra fields on Posix platforms. Since
  60   // NaCl is a Posix environment, it gets that version of the header. This
  61   // header is duplicated here so we have a cross-platform definition of the
  62   // header we're exposing to NaCl.
  63 #pragma pack(push, 4)
  64   struct NaClMessageHeader : public base::Pickle::Header {
  65     int32 routing;
  66     uint32 type;
  67     uint32 flags;
  68     uint16 num_fds;
  69     uint16 pad;
  70   };
  71 #pragma pack(pop)
  72
  73   typedef base::Callback<void(IPC::PlatformFileForTransit, base::FilePath)>
  74       ResolveFileTokenReplyCallback;
  75
  76   typedef base::Callback<void(uint64_t,  // file_token_lo
  77                               uint64_t,  // file_token_hi
  78                               ResolveFileTokenReplyCallback)>
  79       ResolveFileTokenCallback;
  80
  81   typedef base::Callback<void(const IPC::Message&,
  82                               IPC::PlatformFileForTransit,
  83                               base::FilePath)> OpenResourceReplyCallback;
  84
  85   typedef base::Callback<bool(const IPC::Message&,
  86                               const std::string&,  // key
  87                               OpenResourceReplyCallback)> OpenResourceCallback;
  88
  89   // Creates an adapter, using the thread associated with the given task
  90   // runner for posting messages. In normal use, the task runner will post to
  91   // the I/O thread of the process.
  92   //
  93   // If you use this constructor, you MUST call ConnectChannel after the
  94   // NaClIPCAdapter is constructed, or the NaClIPCAdapter's channel will not be
  95   // connected.
  96   //
  97   // |resolve_file_token_cb| is an optional callback to be invoked for
  98   // resolving file tokens received from the renderer. When the file token
  99   // is resolved, the ResolveFileTokenReplyCallback passed inside the
 100   // ResolveFileTokenCallback will be invoked. |open_resource_cb| is also an
 101   // optional callback to be invoked for intercepting open_resource IRT calls.
 102   // |open_resource_cb| may immediately call a OpenResourceReplyCallback
 103   // function to send a pre-opened resource descriptor to the untrusted side.
 104   // OpenResourceCallback returns true when OpenResourceReplyCallback is called.
 105   NaClIPCAdapter(
 106       const IPC::ChannelHandle& handle,
 107       base::TaskRunner* runner,
 108       ResolveFileTokenCallback resolve_file_token_cb,
 109       OpenResourceCallback open_resource_cb);
 110
 111   // Initializes with a given channel that's already created for testing
 112   // purposes. This function will take ownership of the given channel.
 113   NaClIPCAdapter(scoped_ptr<IPC::Channel> channel, base::TaskRunner* runner);
 114
 115   // Connect the channel. This must be called after the constructor that accepts
 116   // an IPC::ChannelHandle, and causes the Channel to be connected on the IO
 117   // thread.
 118   void ConnectChannel();
 119
 120   // Implementation of sendmsg. Returns the number of bytes written or -1 on
 121   // failure.
 122   int Send(const NaClImcTypedMsgHdr* msg);
 123
 124   // Implementation of recvmsg. Returns the number of bytes read or -1 on
 125   // failure. This will block until there's an error or there is data to
 126   // read.
 127   int BlockingReceive(NaClImcTypedMsgHdr* msg);
 128
 129   // Closes the IPC channel.
 130   void CloseChannel();
 131
 132   // Make a NaClDesc that refers to this NaClIPCAdapter. Note that the returned
 133   // NaClDesc is reference-counted, and a reference is returned.
 134   NaClDesc* MakeNaClDesc();
 135
 136 #if defined(OS_POSIX)
 137   base::ScopedFD TakeClientFileDescriptor();
 138 #endif
 139
 140   // Listener implementation.
 141   bool OnMessageReceived(const IPC::Message& message) override;
 142   void OnChannelConnected(int32 peer_pid) override;
 143   void OnChannelError() override;
 144
 145  private:
 146   friend class base::RefCountedThreadSafe<NaClIPCAdapter>;
 147
 148   class RewrittenMessage;
 149
 150   // This is the data that must only be accessed inside the lock. This struct
 151   // just separates it so it's easier to see.
 152   struct LockedData {
 153     LockedData();
 154     ~LockedData();
 155
 156     // Messages that we have read off of the Chrome IPC channel that are waiting
 157     // to be received by the plugin.
 158     std::queue< scoped_refptr<RewrittenMessage> > to_be_received_;
 159
 160     ppapi::proxy::NaClMessageScanner nacl_msg_scanner_;
 161
 162     // Data that we've queued from the plugin to send, but doesn't consist of a
 163     // full message yet. The calling code can break apart the message into
 164     // smaller pieces, and we need to send the message to the other process in
 165     // one chunk.
 166     //
 167     // The IPC channel always starts a new send() at the beginning of each
 168     // message, so we don't need to worry about arbitrary message boundaries.
 169     std::string to_be_sent_;
 170
 171     bool channel_closed_;
 172   };
 173
 174   // This is the data that must only be accessed on the I/O thread (as defined
 175   // by TaskRunner). This struct just separates it so it's easier to see.
 176   struct IOThreadData {
 177     IOThreadData();
 178     ~IOThreadData();
 179
 180     scoped_ptr<IPC::Channel> channel_;
 181
 182     // When we send a synchronous message (from untrusted to trusted), we store
 183     // its type here, so that later we can associate the reply with its type
 184     // for scanning.
 185     typedef std::map<int, uint32> PendingSyncMsgMap;
 186     PendingSyncMsgMap pending_sync_msgs_;
 187   };
 188
 189   ~NaClIPCAdapter() override;
 190
 191   void SaveOpenResourceMessage(const IPC::Message& orig_msg,
 192                                IPC::PlatformFileForTransit ipc_fd,
 193                                base::FilePath file_path);
 194
 195   bool RewriteMessage(const IPC::Message& msg, uint32_t type);
 196
 197   // Returns 0 if nothing is waiting.
 198   int LockedReceive(NaClImcTypedMsgHdr* msg);
 199
 200   // Sends a message that we know has been completed to the Chrome process.
 201   bool SendCompleteMessage(const char* buffer, size_t buffer_len);
 202
 203   // Clears the LockedData.to_be_sent_ structure in a way to make sure that
 204   // the memory is deleted. std::string can sometimes hold onto the buffer
 205   // for future use which we don't want.
 206   void ClearToBeSent();
 207
 208   void ConnectChannelOnIOThread();
 209   void CloseChannelOnIOThread();
 210   void SendMessageOnIOThread(scoped_ptr<IPC::Message> message);
 211
 212   // Saves the message to forward to NaCl. This method assumes that the caller
 213   // holds the lock for locked_data_.
 214   void SaveMessage(const IPC::Message& message,
 215                    RewrittenMessage* rewritten_message);
 216
 217   base::Lock lock_;
 218   base::ConditionVariable cond_var_;
 219
 220   scoped_refptr<base::TaskRunner> task_runner_;
 221
 222   ResolveFileTokenCallback resolve_file_token_cb_;
 223   OpenResourceCallback open_resource_cb_;
 224
 225   // To be accessed inside of lock_ only.
 226   LockedData locked_data_;
 227
 228   // To be accessed on the I/O thread (via task runner) only.
 229   IOThreadData io_thread_data_;
 230
 231   DISALLOW_COPY_AND_ASSIGN(NaClIPCAdapter);
 232 };
 233
 234 // Export TranslatePepperFileReadWriteOpenFlags for testing.
 235 int TranslatePepperFileReadWriteOpenFlagsForTesting(int32_t pp_open_flags);
 236
 237 #endif  // COMPONENTS_NACL_LOADER_NACL_IPC_ADAPTER_H_