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