service_runtime/include/sys/nacl_imc_api.h

   1 /*
   2  * Copyright 2008, Google Inc.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are
   7  * met:
   8  *
   9  *     * Redistributions of source code must retain the above copyright
  10  * notice, this list of conditions and the following disclaimer.
  11  *     * Redistributions in binary form must reproduce the above
  12  * copyright notice, this list of conditions and the following disclaimer
  13  * in the documentation and/or other materials provided with the
  14  * distribution.
  15  *     * Neither the name of Google Inc. nor the names of its
  16  * contributors may be used to endorse or promote products derived from
  17  * this software without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  20  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  21  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  22  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  23  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  29  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 /*
  33  * NaCl Service Runtime.  IMC API.
  34  */
  35
  36 #ifndef NATIVE_CLIENT_SERVICE_RUNTIME_INCLUDE_SYS_NACL_IMC_API_H_
  37 #define NATIVE_CLIENT_SERVICE_RUNTIME_INCLUDE_SYS_NACL_IMC_API_H_
  38
  39 /*
  40  * This file defines the C API for NativeClient applications.  The
  41  * ABI is implicitly defined.
  42  */
  43
  44 #include "native_client/service_runtime/include/bits/nacl_imc_api.h"
  45
  46 #ifdef __cplusplus
  47 extern "C" {
  48 #endif
  49
  50 /* TODO: there should be one instance to avoid conflicting definitions.
  51  */
  52 #ifndef __nacl_handle_defined
  53 #define __nacl_handle_defined
  54 #if NACL_WINDOWS
  55 typedef HANDLE NaClHandle;
  56 #else
  57 typedef int NaClHandle;
  58 #endif
  59 #endif
  60
  61 struct NaClImcMsgIoVec {
  62   void    *base;
  63   size_t  length;
  64 };
  65
  66 struct NaClImcMsgHdr {
  67   struct NaClImcMsgIoVec  *iov;
  68   size_t                  iov_length;
  69   int                     *descv;
  70   size_t                  desc_length;
  71   int                     flags;
  72 };
  73
  74 /*
  75  * NACL_ABI_IMC_IOVEC_MAX: How many struct NaClIOVec are permitted?
  76  * These are copied to kernel space in order to translate/validate
  77  * addresses, and are on the thread stack when processing
  78  * NaClSysSendmsg and NaClSysRecvmsg syscalls.  Each object takes 8
  79  * bytes, so beware running into NACL_KERN_STACK_SIZE above.
  80  */
  81 #define NACL_ABI_IMC_IOVEC_MAX      256
  82
  83 /*
  84  * NAC_ABI_IMC_DESC_MAX: How many descriptors are permitted?  Each
  85  * object is 4 bytes.  An array of ints are on the kernel stack.
  86  *
  87  * TODO: coordinate w/ NACL_HANDLE_COUNT_MAX in nacl_imc_c.h.
  88  * Current IMC-imposed limit seems way too small.
  89  */
  90 #define NACL_ABI_IMC_USER_DESC_MAX  8
  91 #define NACL_ABI_IMC_DESC_MAX       8
  92
  93 /*
  94  * NACL_ABI_IMC_USER_BYTES_MAX: read must go into a kernel buffer first
  95  * before a variable-length header describing the number and types of
  96  * NaClHandles encoded is parsed, with the rest of the data not yet
  97  * consumed turning into user data.
  98  */
  99 #define NACL_ABI_IMC_USER_BYTES_MAX    (128 << 10)
 100 #define NACL_ABI_IMC_BYTES_MAX                   \
 101   (NACL_ABI_IMC_USER_BYTES_MAX                   \
 102    + (1 + NACL_PATH_MAX) * NACL_ABI_IMC_USER_DESC_MAX + 16)
 103 /*
 104  * 4096 + (1 + 28) * 256 = 11520, so the read buffer must be malloc'd
 105  * or be part of the NaClAppThread structure; the kernel thread stack
 106  * is too small for it.
 107  *
 108  * NB: the header has an end tag and the size is rounded up to the
 109  * next 16 bytes.
 110  */
 111
 112 #ifdef __cplusplus
 113 }
 114 #endif
 115
 116 #endif  /* NATIVE_CLIENT_SERVICE_RUNTIME_INCLUDE_SYS_NACL_IMC_API_H_ */