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