sandbox/win/src/sharedmem_ipc_server.h

   1 // Copyright (c) 2012 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 SANDBOX_SRC_SHAREDMEM_IPC_SERVER_H_
   6 #define SANDBOX_SRC_SHAREDMEM_IPC_SERVER_H_
   7
   8 #include <list>
   9
  10 #include "base/basictypes.h"
  11 #include "base/gtest_prod_util.h"
  12 #include "base/win/scoped_handle.h"
  13 #include "sandbox/win/src/crosscall_params.h"
  14 #include "sandbox/win/src/crosscall_server.h"
  15 #include "sandbox/win/src/sharedmem_ipc_client.h"
  16
  17 // IPC transport implementation that uses shared memory.
  18 // This is the server side
  19 //
  20 // The server side has knowledge about the layout of the shared memory
  21 // and the state transitions. Both are explained in sharedmem_ipc_client.h
  22 //
  23 // As opposed to SharedMemIPClient, the Server object should be one for the
  24 // entire lifetime of the target process. The server is in charge of creating
  25 // the events (ping, pong) both for the client and for the target that are used
  26 // to signal the IPC and also in charge of setting the initial state of the
  27 // channels.
  28 //
  29 // When an IPC is ready, the server relies on being called by on the
  30 // ThreadPingEventReady callback. The IPC server then retrieves the buffer,
  31 // marshals it into a CrossCallParam object and calls the Dispatcher, who is in
  32 // charge of fulfilling the IPC request.
  33 namespace sandbox {
  34
  35 // the shared memory implementation of the IPC server. There should be one
  36 // of these objects per target (IPC client) process
  37 class SharedMemIPCServer {
  38  public:
  39   // Creates the IPC server.
  40   // target_process: handle to the target process. It must be suspended. It is
  41   // unfortunate to receive a raw handle (and store it inside this object) as
  42   // that dilutes ownership of the process, but in practice a SharedMemIPCServer
  43   // is owned by TargetProcess, which calls this method, and owns the handle, so
  44   // everything is safe. If that changes, we should break this dependency and
  45   // duplicate the handle instead.
  46   // target_process_id: process id of the target process.
  47   // thread_provider: a thread provider object.
  48   // dispatcher: an object that can service IPC calls.
  49   SharedMemIPCServer(HANDLE target_process, DWORD target_process_id,
  50                      ThreadProvider* thread_provider, Dispatcher* dispatcher);
  51
  52   ~SharedMemIPCServer();
  53
  54   // Initializes the server structures, shared memory structures and
  55   // creates the kernels events used to signal the IPC.
  56   bool Init(void* shared_mem, uint32 shared_size, uint32 channel_size);
  57
  58  private:
  59   // Allow tests to be marked DISABLED_. Note that FLAKY_ and FAILS_ prefixes
  60   // do not work with sandbox tests.
  61   FRIEND_TEST_ALL_PREFIXES(IPCTest, SharedMemServerTests);
  62   // When an event fires (IPC request). A thread from the ThreadProvider
  63   // will call this function. The context parameter should be the same as
  64   // provided when ThreadProvider::RegisterWait was called.
  65   static void __stdcall ThreadPingEventReady(void* context,
  66                                              unsigned char);
  67
  68   // Makes the client and server events. This function is called once
  69   // per channel.
  70   bool MakeEvents(base::win::ScopedHandle* server_ping,
  71                   base::win::ScopedHandle* server_pong,
  72                   HANDLE* client_ping, HANDLE* client_pong);
  73
  74   // A copy this structure is maintained per channel.
  75   // Note that a lot of the fields are just the same of what we have in the IPC
  76   // object itself. It is better to have the copies since we can dispatch in the
  77   // static method without worrying about converting back to a member function
  78   // call or about threading issues.
  79   struct ServerControl {
  80     ServerControl();
  81     ~ServerControl();
  82
  83     // This channel server ping event.
  84     base::win::ScopedHandle ping_event;
  85     // This channel server pong event.
  86     base::win::ScopedHandle pong_event;
  87     // The size of this channel.
  88     uint32 channel_size;
  89     // The pointer to the actual channel data.
  90     char* channel_buffer;
  91     // The pointer to the base of the shared memory.
  92     char* shared_base;
  93     // A pointer to this channel's client-side control structure this structure
  94     // lives in the shared memory.
  95     ChannelControl* channel;
  96     // the IPC dispatcher associated with this channel.
  97     Dispatcher* dispatcher;
  98     // The target process information associated with this channel.
  99     ClientInfo target_info;
 100   };
 101
 102   // Looks for the appropriate handler for this IPC and invokes it.
 103   static bool InvokeCallback(const ServerControl* service_context,
 104                              void* ipc_buffer, CrossCallReturn* call_result);
 105
 106   // Points to the shared memory channel control which lives at
 107   // the start of the shared section.
 108   IPCControl* client_control_;
 109
 110   // Keeps track of the server side objects that are used to answer an IPC.
 111   typedef std::list<ServerControl*> ServerContexts;
 112   ServerContexts server_contexts_;
 113
 114   // The thread provider provides the threads that call back into this object
 115   // when the IPC events fire.
 116   ThreadProvider* thread_provider_;
 117
 118   // The IPC object is associated with a target process.
 119   HANDLE target_process_;
 120
 121   // The target process id associated with the IPC object.
 122   DWORD target_process_id_;
 123
 124   // The dispatcher handles 'ready' IPC calls.
 125   Dispatcher* call_dispatcher_;
 126
 127   DISALLOW_COPY_AND_ASSIGN(SharedMemIPCServer);
 128 };
 129
 130 }  // namespace sandbox
 131
 132 #endif  // SANDBOX_SRC_SHAREDMEM_IPC_SERVER_H_