1
2/*--------------------------------------------------------------------*/
3/*--- Function replacement and wrapping.          pub_core_redir.h ---*/
4/*--------------------------------------------------------------------*/
5
6/*
7   This file is part of Valgrind, a dynamic binary instrumentation
8   framework.
9
10   Copyright (C) 2000-2013 Julian Seward
11      jseward@acm.org
12
13   This program is free software; you can redistribute it and/or
14   modify it under the terms of the GNU General Public License as
15   published by the Free Software Foundation; either version 2 of the
16   License, or (at your option) any later version.
17
18   This program is distributed in the hope that it will be useful, but
19   WITHOUT ANY WARRANTY; without even the implied warranty of
20   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
21   General Public License for more details.
22
23   You should have received a copy of the GNU General Public License
24   along with this program; if not, write to the Free Software
25   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
26   02111-1307, USA.
27
28   The GNU General Public License is contained in the file COPYING.
29*/
30
31#ifndef __PUB_CORE_REDIR_H
32#define __PUB_CORE_REDIR_H
33
34//--------------------------------------------------------------------
35// PURPOSE: This module deals with:
36//
37// - code replacement: intercepting calls to client functions, and
38//   pointing them to a different piece of code.
39//
40// - loading notification: telling the core where certain client-space
41//   functions are when they get loaded.
42//
43// - function wrapping: add calls to code before and after client
44//   functions execute, for inspection and/or modification.
45//
46// - checking of --require-text-symbol= specifications: when a new
47//   object is loaded, its symbol table is examined, and if a symbol
48//   (as required by the specifications) is not found then the run
49//   is aborted.  See comment by VG_(clo_n_req_tsyms) in
50//   pub_core_options.h for background.  This doesn't have anything
51//   to do with function intercepting or wrapping, but it does have
52//   to do with examining all symbols at object load time, so this
53//   module seems like a logical place to put it.
54//
55//--------------------------------------------------------------------
56
57#include "pub_tool_redir.h"
58#include "pub_core_basics.h"      // Addr
59#include "pub_core_debuginfo.h"   // DebugInfo
60
61//--------------------------------------------------------------------
62// Notifications - by which we are told of state changes
63//--------------------------------------------------------------------
64
65/* Notify the module of a new DebugInfo (called from m_debuginfo). */
66extern void VG_(redir_notify_new_DebugInfo)( DebugInfo* );
67
68/* Notify the module of the disappearance of a DebugInfo (also called
69   from m_debuginfo). */
70extern void VG_(redir_notify_delete_DebugInfo)( DebugInfo* );
71
72/* Initialise the module, and load initial "hardwired" redirects. */
73extern void VG_(redir_initialise)( void );
74
75/* Notify the module of a new target for an indirect function. */
76extern void VG_(redir_add_ifunc_target)( Addr old_from, Addr new_from );
77
78//--------------------------------------------------------------------
79// Queries
80//--------------------------------------------------------------------
81
82/* This is the crucial redirection function.  It answers the question:
83   should this code address be redirected somewhere else?  It's used
84   just before translating a basic block.  If a redir is found,
85   *isWrap allows to distinguish wrap- from replace- style
86   redirections. */
87extern Addr VG_(redir_do_lookup) ( Addr orig, Bool* isWrap );
88
89
90//--------------------------------------------------------------------
91// Loading notification
92//--------------------------------------------------------------------
93
94/* Functions named with this macro have the property that the core will
95   be told what their address is when they are loaded.  This can be useful
96   if the core wants to call them at some point, and so needs to know their
97   address.  This is a weaker but more general mechanism than code
98   replacement.
99
100   Functions named with this macro should be in client space, ie. in
101   vgpreload_<tool>.h or vgpreload_core.h. */
102
103#define VG_NOTIFY_ON_LOAD(name)           _vgnU_##name
104#define VG_NOTIFY_ON_LOAD_PREFIX          "_vgnU_"
105#define VG_NOTIFY_ON_LOAD_PREFIX_LEN      6
106
107
108//--------------------------------------------------------------------
109// Function wrapping
110//--------------------------------------------------------------------
111
112// This is currently not working(?) --njn
113
114/* Wrapping machinery */
115//enum return_type {
116  //   RT_RETURN,
117   //   RT_LONGJMP,
118   //   RT_EXIT,
119   //};
120//
121//typedef struct _FuncWrapper FuncWrapper;
122//struct _FuncWrapper {
123  //   void *(*before)(va_list args);
124  //   void  (*after) (void *nonce, enum return_type, Word retval);
125  //};
126//
127//extern void VG_(wrap_function)(Addr eip, const FuncWrapper *wrapper);
128//extern const FuncWrapper *VG_(is_wrapped)(Addr eip);
129//extern Bool VG_(is_wrapper_return)(Addr eip);
130
131/* Primary interface for adding wrappers for client-side functions. */
132//extern CodeRedirect *VG_(add_wrapper)(const HChar *from_lib, const HChar *from_sym,
133//				      const FuncWrapper *wrapper);
134//
135//extern Bool VG_(is_resolved)(const CodeRedirect *redir);
136
137#endif   // __PUB_CORE_REDIR_H
138
139/*--------------------------------------------------------------------*/
140/*--- end                                                          ---*/
141/*--------------------------------------------------------------------*/
142