ppapi/proxy/serialized_handle.h

   1 // Copyright (c) 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 PPAPI_PROXY_SERIALIZED_HANDLES_H_
   6 #define PPAPI_PROXY_SERIALIZED_HANDLES_H_
   7
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/atomicops.h"
  12 #include "base/basictypes.h"
  13 #include "base/logging.h"
  14 #include "base/memory/ref_counted.h"
  15 #include "base/memory/shared_memory.h"
  16 #include "build/build_config.h"
  17 #include "ipc/ipc_platform_file.h"
  18 #include "ppapi/c/pp_resource.h"
  19 #include "ppapi/proxy/ppapi_proxy_export.h"
  20
  21 namespace base {
  22 class Pickle;
  23 }
  24
  25 namespace ppapi {
  26 namespace proxy {
  27
  28 // SerializedHandle is a unified structure for holding a handle (e.g., a shared
  29 // memory handle, socket descriptor, etc). This is useful for passing handles in
  30 // resource messages and also makes it easier to translate handles in
  31 // NaClIPCAdapter for use in NaCl.
  32 class PPAPI_PROXY_EXPORT SerializedHandle {
  33  public:
  34   enum Type { INVALID, SHARED_MEMORY, SOCKET, FILE };
  35   // Header contains the fields that we send in IPC messages, apart from the
  36   // actual handle. See comments on the SerializedHandle fields below.
  37   struct Header {
  38     Header() : type(INVALID), size(0), open_flags(0) {}
  39     Header(Type type_arg,
  40            uint32 size_arg,
  41            int32 open_flags_arg,
  42            PP_Resource file_io_arg)
  43         : type(type_arg),
  44           size(size_arg),
  45           open_flags(open_flags_arg),
  46           file_io(file_io_arg) {
  47     }
  48
  49     Type type;
  50     uint32 size;
  51     int32 open_flags;
  52     PP_Resource file_io;
  53   };
  54
  55   SerializedHandle();
  56   // Create an invalid handle of the given type.
  57   explicit SerializedHandle(Type type);
  58
  59   // Create a shared memory handle.
  60   SerializedHandle(const base::SharedMemoryHandle& handle, uint32 size);
  61
  62   // Create a socket or file handle.
  63   SerializedHandle(const Type type,
  64                    const IPC::PlatformFileForTransit& descriptor);
  65
  66   Type type() const { return type_; }
  67   bool is_shmem() const { return type_ == SHARED_MEMORY; }
  68   bool is_socket() const { return type_ == SOCKET; }
  69   bool is_file() const { return type_ == FILE; }
  70   const base::SharedMemoryHandle& shmem() const {
  71     DCHECK(is_shmem());
  72     return shm_handle_;
  73   }
  74   uint32 size() const {
  75     DCHECK(is_shmem());
  76     return size_;
  77   }
  78   const IPC::PlatformFileForTransit& descriptor() const {
  79     DCHECK(is_socket() || is_file());
  80     return descriptor_;
  81   }
  82   int32 open_flags() const {
  83     return open_flags_;
  84   }
  85   PP_Resource file_io() const {
  86     return file_io_;
  87   }
  88   void set_shmem(const base::SharedMemoryHandle& handle, uint32 size) {
  89     type_ = SHARED_MEMORY;
  90     shm_handle_ = handle;
  91     size_ = size;
  92
  93     descriptor_ = IPC::InvalidPlatformFileForTransit();
  94   }
  95   void set_socket(const IPC::PlatformFileForTransit& socket) {
  96     type_ = SOCKET;
  97     descriptor_ = socket;
  98
  99     shm_handle_ = base::SharedMemory::NULLHandle();
 100     size_ = 0;
 101   }
 102   void set_file_handle(const IPC::PlatformFileForTransit& descriptor,
 103                        int32 open_flags,
 104                        PP_Resource file_io) {
 105     type_ = FILE;
 106
 107     descriptor_ = descriptor;
 108     shm_handle_ = base::SharedMemory::NULLHandle();
 109     size_ = 0;
 110     open_flags_ = open_flags;
 111     file_io_ = file_io;
 112   }
 113   void set_null_shmem() {
 114     set_shmem(base::SharedMemory::NULLHandle(), 0);
 115   }
 116   void set_null_socket() {
 117     set_socket(IPC::InvalidPlatformFileForTransit());
 118   }
 119   void set_null_file_handle() {
 120     set_file_handle(IPC::InvalidPlatformFileForTransit(), 0, 0);
 121   }
 122   bool IsHandleValid() const;
 123
 124   Header header() const {
 125     return Header(type_, size_, open_flags_, file_io_);
 126   }
 127
 128   // Closes the handle and sets it to invalid.
 129   void Close();
 130
 131   // Write/Read a Header, which contains all the data except the handle. This
 132   // allows us to write the handle in a platform-specific way, as is necessary
 133   // in NaClIPCAdapter to share handles with NaCl from Windows.
 134   static bool WriteHeader(const Header& hdr, base::Pickle* pickle);
 135   static bool ReadHeader(base::PickleIterator* iter, Header* hdr);
 136
 137  private:
 138   // The kind of handle we're holding.
 139   Type type_;
 140
 141   // We hold more members than we really need; we can't easily use a union,
 142   // because we hold non-POD types. But these types are pretty light-weight. If
 143   // we add more complex things later, we should come up with a more memory-
 144   // efficient strategy.
 145   // These are valid if type == SHARED_MEMORY.
 146   base::SharedMemoryHandle shm_handle_;
 147   uint32 size_;
 148
 149   // This is valid if type == SOCKET || type == FILE.
 150   IPC::PlatformFileForTransit descriptor_;
 151
 152   // The following fields are valid if type == FILE.
 153   int32 open_flags_;
 154   // This is non-zero if file writes require quota checking.
 155   PP_Resource file_io_;
 156 };
 157
 158 }  // namespace proxy
 159 }  // namespace ppapi
 160
 161 #endif  // PPAPI_PROXY_SERIALIZED_HANDLES_H_