syscall_emul_buf.hh revision 10497:73a59d5e0923 
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 */
56class 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    virtual ~BaseBufferArg() { delete [] bufPtr; }
74
75    /**
76     * copy data into simulator space (read from target memory)
77     */
78    virtual 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    virtual 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 */
103class 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 */
127template <class T>
128class 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__
169