service_runtime/linux/nacl_syscall_inl.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 syscall inline header file.
  34  */
  35
  36 #ifndef NATIVE_CLIENT_SERVICE_RUNTIME_LINUX_NACL_SYSCALL_INL_H_
  37 #define NATIVE_CLIENT_SERVICE_RUNTIME_LINUX_NACL_SYSCALL_INL_H_
  38
  39 static INLINE uint32_t NaClAppArg(struct NaClAppThread *natp,
  40                                   int                  wordnum)
  41 {
  42   return natp->x_esp[wordnum];
  43 }
  44
  45 /*
  46  * Syscall return value mapper.  The linux raw syscall convention is
  47  * that anything positive and anything smaller than a certain negative
  48  * number are valid return values (think addresses in the 2GB range,
  49  * since user addresses may be in the first 3 GB, and the kernel lives
  50  * in the 4th GB), and anything else (smallish negative numbers) are
  51  * errors from Linux (possibly OSX).  In such a case, the syscall
  52  * wrapper will take the negative value and store it into the
  53  * thread-specific errno variable, and return -1 instead.  Since we
  54  * are using these wrappers, we merely detect when any host OS syscall
  55  * returned -1, and pass -errno back to the NaCl app.  (The syscall
  56  * wrappers on the NaCl app side will similarly follow the
  57  * negative-values-are-errors convention).
  58  */
  59 static INLINE int32_t NaClXlateSysRet(int32_t  rv)
  60 {
  61   return (rv != -1) ? rv : -NaClXlateErrno(errno);
  62 }
  63
  64 /*
  65  * TODO: NaClXlateSysRetDesc to register returned descriptor in the
  66  * app's open descriptor table, wrapping it in a native descriptor
  67  * object.
  68  */
  69
  70 static INLINE int32_t NaClXlateSysRetAddr(struct NaClApp  *nap,
  71                                           int32_t         rv)
  72 {
  73   /* if rv is a bad address, we abort */
  74   return ((rv != -1)
  75           ? (int32_t) NaClSysToUser(nap, rv)
  76           : -NaClXlateErrno(errno));
  77 }
  78
  79 #endif