intermodule_comm/nacl_htp.h

   1 /*
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  31
  32
  33 // NaCl Handle Transfer Protocol
  34 //
  35 // The NaCl sel_ldr uses the NaCl Handle Transfer Protocol to send/receive
  36 // messages between NaCl modules. This module provides the utility functions
  37 // to communicate with a NaCl module from the trusted code.
  38
  39 #ifndef NATIVE_CLIENT_INTERMODULE_COMM_NACL_HTP_H_
  40 #define NATIVE_CLIENT_INTERMODULE_COMM_NACL_HTP_H_
  41
  42
  43 #include <stdlib.h>
  44 #ifdef __native_client__
  45 #include <unistd.h>
  46 #include <nacl/nacl_imc.h>
  47 #else
  48 #include "native_client/intermodule_comm/nacl_imc.h"
  49 #endif  // __native_client__
  50
  51 #ifdef __native_client__
  52
  53 namespace nacl {
  54
  55 typedef Handle        HtpHandle;
  56 typedef MessageHeader HtpHeader;
  57
  58 // Creates a host I/O descriptor from the handle.
  59 inline HtpHandle CreateIoDesc(Handle handle) {
  60   return handle;
  61 }
  62
  63 // Creates a shared memory descriptor from the handle.
  64 inline HtpHandle CreateShmDesc(Handle handle, off_t length) {
  65   return handle;
  66 }
  67
  68 // Creates an IMC memory descriptor from the handle.
  69 inline HtpHandle CreateImcDesc(Handle handle) {
  70   return handle;
  71 }
  72
  73 // Reads up to count bytes from the handle into buffer.
  74 inline int Read(HtpHandle handle, void* buffer, size_t count) {
  75   return read(handle, buffer, count);
  76 }
  77
  78 // Writes up to count bytes to the handle from buffer.
  79 inline int Write(HtpHandle handle, const void* buffer, size_t count) {
  80   return write(handle, buffer, count);
  81 }
  82
  83 const HtpHandle kInvalidHtpHandle = kInvalidHandle;
  84
  85 }  // namespace nacl
  86
  87 #else  // __native_client__
  88
  89 struct NaClDesc;
  90
  91 namespace nacl {
  92
  93 // NaCl resource descriptor type compatible with sel_ldr.
  94 typedef struct NaClDesc* HtpHandle;
  95
  96 // Message header used by SendDatagram() and ReceiveDatagram().
  97 // Note the member layout is compatible with NaClImcTypedMsgHdr{}.
  98 struct HtpHeader {
  99   IOVec*     iov;            // scatter/gather array
 100   size_t     iov_length;     // number of elements in iov
 101   HtpHandle* handles;        // array of handles to be transferred
 102   size_t     handle_count;   // number of handles in handles
 103   int        flags;
 104 };
 105
 106 // Sends a message on a socket. Except for the fact that HtpHeader is used,
 107 // the runtime behavior of this function is the same as SendDatagram() for
 108 // MessageHeader.
 109 // On success, SendDatagram() returns the number of bytes sent.
 110 int SendDatagram(HtpHandle socket, const HtpHeader* message, int flags);
 111
 112 // Receives a message from a socket.  Except for the fact that HtpHeader is
 113 // used, the runtime behavior of this function is the same as ReceiveDatagram()
 114 // for MessageHeader.
 115 // On success, ReceiveDatagram() returns the number of bytes received.
 116 int ReceiveDatagram(HtpHandle socket, HtpHeader* message, int flags);
 117
 118 // Closes a sel_ldr compatible NaCl descriptor.
 119 int Close(HtpHandle handle);
 120
 121 // Maps the specified memory object into the process address space.
 122 // Map() returns a pointer to the mapped area, or kMapFailed upon error.
 123 // For prot, the bitwise OR of the kProt* bits must be specified.
 124 // For flags, either kMapShared or kMapPrivate must be specified. If kMapFixed
 125 // is also set, Map() tries to map the memory object at the address specified by
 126 // start.
 127 void* Map(void* start, size_t length, int prot, int flags,
 128           HtpHandle memory, off_t offset);
 129
 130 // Creates a host I/O descriptor from the handle.
 131 HtpHandle CreateIoDesc(Handle handle);
 132
 133 // Creates a shared memory descriptor from the handle.
 134 HtpHandle CreateShmDesc(Handle handle, off_t length);
 135
 136 // Creates an IMC memory descriptor from the handle.
 137 HtpHandle CreateImcDesc(Handle handle);
 138
 139 // Reads up to count bytes from the handle into buffer.
 140 int Read(HtpHandle handle, void* buffer, size_t count);
 141
 142 // Writes up to count bytes to the handle from buffer.
 143 int Write(HtpHandle handle, const void* buffer, size_t count);
 144
 145 const HtpHandle kInvalidHtpHandle = NULL;
 146
 147 }  // namespace nacl
 148
 149 #endif  // __native_client__
 150
 151 #endif  // NATIVE_CLIENT_INTERMODULE_COMM_NACL_HTP_H_