src/sim/syscall_emul_buf.hh

   1 /*
   2  * Copyright (c) 2003-2005 The Regents of The University of Michigan
   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: redistributions of source code must retain the above copyright
   8  * notice, this list of conditions and the following disclaimer;
   9  * redistributions in binary form must reproduce the above copyright
  10  * notice, this list of conditions and the following disclaimer in the
  11  * documentation and/or other materials provided with the distribution;
  12  * neither the name of the copyright holders nor the names of its
  13  * contributors may be used to endorse or promote products derived from
  14  * this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  17  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  18  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  19  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  20  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  21  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  22  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  26  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  *
  28  * Authors: Steve Reinhardt
  29  */
  30
  31 #ifndef __SIM_SYSCALL_EMUL_BUF_HH__
  32 #define __SIM_SYSCALL_EMUL_BUF_HH__
  33
  34 ///
  35 /// @file syscall_emul_buf.hh
  36 ///
  37 /// This file defines buffer classes used to handle pointer arguments
  38 /// in emulated syscalls.
  39
  40 #include <cstring>
  41
  42 #include "base/types.hh"
  43 #include "mem/se_translating_port_proxy.hh"
  44
  45 /**
  46  * Base class for BufferArg and TypedBufferArg, Not intended to be
  47  * used directly.
  48  *
  49  * The BufferArg classes represent buffers in target user space that
  50  * are passed by reference to an (emulated) system call.  Each
  51  * instance provides an internal (simulator-space) buffer of the
  52  * appropriate size and tracks the user-space address.  The copyIn()
  53  * and copyOut() methods copy the user-space buffer to and from the
  54  * simulator-space buffer, respectively.
  55  */
  56 class BaseBufferArg {
  57
  58   public:
  59
  60     /**
  61      * Allocate a buffer of size 'size' representing the memory at
  62      * target address 'addr'.
  63      */
  64     BaseBufferArg(Addr _addr, int _size)
  65         : addr(_addr), size(_size), bufPtr(new uint8_t[size])
  66     {
  67         // clear out buffer: in case we only partially populate this,
  68         // and then do a copyOut(), we want to make sure we don't
  69         // introduce any random junk into the simulated address space
  70         memset(bufPtr, 0, size);
  71     }
  72
  73     ~BaseBufferArg() { delete [] bufPtr; }
  74
  75     /**
  76      * copy data into simulator space (read from target memory)
  77      */
  78     bool copyIn(SETranslatingPortProxy &memproxy)
  79     {
  80         memproxy.readBlob(addr, bufPtr, size);
  81         return true;    // no EFAULT detection for now
  82     }
  83
  84     /**
  85      * copy data out of simulator space (write to target memory)
  86      */
  87     bool copyOut(SETranslatingPortProxy &memproxy)
  88     {
  89         memproxy.writeBlob(addr, bufPtr, size);
  90         return true;    // no EFAULT detection for now
  91     }
  92
  93   protected:
  94     const Addr addr;        ///< address of buffer in target address space
  95     const int size;         ///< buffer size
  96     uint8_t * const bufPtr; ///< pointer to buffer in simulator space
  97 };
  98
  99 /**
 100  * BufferArg represents an untyped buffer in target user space that is
 101  * passed by reference to an (emulated) system call.
 102  */
 103 class BufferArg : public BaseBufferArg
 104 {
 105   public:
 106     /**
 107      * Allocate a buffer of size 'size' representing the memory at
 108      * target address 'addr'.
 109      */
 110     BufferArg(Addr _addr, int _size) : BaseBufferArg(_addr, _size) { }
 111
 112     /**
 113      * Return a pointer to the internal simulator-space buffer.
 114      */
 115     void *bufferPtr() { return bufPtr; }
 116 };
 117
 118 /**
 119  * TypedBufferArg is a class template; instances of this template
 120  * represent typed buffers in target user space that are passed by
 121  * reference to an (emulated) system call.
 122  *
 123  * This template provides operator overloads for convenience, allowing
 124  * for example the use of '->' to reference fields within a struct
 125  * type.
 126  */
 127 template <class T>
 128 class TypedBufferArg : public BaseBufferArg
 129 {
 130   public:
 131     /**
 132      * Allocate a buffer of type T representing the memory at target
 133      * address 'addr'. The user can optionally specify a specific
 134      * number of bytes to allocate to deal with structs that have
 135      * variable-size arrays at the end.
 136      */
 137     TypedBufferArg(Addr _addr, int _size = sizeof(T))
 138         : BaseBufferArg(_addr, _size)
 139     { }
 140
 141     /**
 142      * Convert TypedBufferArg<T> to a pointer to T that points to the
 143      * internal buffer.
 144      */
 145     operator T*() { return (T *)bufPtr; }
 146
 147     /**
 148      * Convert TypedBufferArg<T> to a reference to T that references the
 149      * internal buffer value.
 150      */
 151     T &operator*()       { return *((T *)bufPtr); }
 152
 153
 154     /**
 155      * Enable the use of '->' to reference fields where T is a struct
 156      * type.
 157      */
 158     T* operator->()      { return (T *)bufPtr; }
 159
 160     /**
 161      * Enable the use of '[]' to reference fields where T is an array
 162      * type.
 163      */
 164     T &operator[](int i) { return ((T *)bufPtr)[i]; }
 165 };
 166
 167
 168 #endif // __SIM_SYSCALL_EMUL_BUF_HH__