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      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) 2000-2010 Julian Seward
     11       jseward (at) 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 
     59 
     60 //--------------------------------------------------------------------
     61 // Notifications - by which we are told of state changes
     62 //--------------------------------------------------------------------
     63 
     64 /* Notify the module of a new DebugInfo (called from m_debuginfo). */
     65 extern void VG_(redir_notify_new_DebugInfo)( DebugInfo* );
     66 
     67 /* Notify the module of the disappearance of a DebugInfo (also called
     68    from m_debuginfo). */
     69 extern void VG_(redir_notify_delete_DebugInfo)( DebugInfo* );
     70 
     71 /* Initialise the module, and load initial "hardwired" redirects. */
     72 extern void VG_(redir_initialise)( void );
     73 
     74 /* Notify the module of a new target for an indirect function. */
     75 extern void VG_(redir_add_ifunc_target)( Addr old_from, Addr new_from );
     76 
     77 //--------------------------------------------------------------------
     78 // Queries
     79 //--------------------------------------------------------------------
     80 
     81 /* This is the crucial redirection function.  It answers the question:
     82    should this code address be redirected somewhere else?  It's used
     83    just before translating a basic block.  If a redir is found,
     84    *isWrap allows to distinguish wrap- from replace- style
     85    redirections. */
     86 extern Addr VG_(redir_do_lookup) ( Addr orig, Bool* isWrap );
     87 
     88 
     89 //--------------------------------------------------------------------
     90 // Loading notification
     91 //--------------------------------------------------------------------
     92 
     93 /* Functions named with this macro have the property that the core will
     94    be told what their address is when they are loaded.  This can be useful
     95    if the core wants to call them at some point, and so needs to know their
     96    address.  This is a weaker but more general mechanism than code
     97    replacement.
     98 
     99    Functions named with this macro should be in client space, ie. in
    100    vgpreload_<tool>.h or vgpreload_core.h. */
    101 
    102 #define VG_NOTIFY_ON_LOAD(name)           _vgnU_##name
    103 #define VG_NOTIFY_ON_LOAD_PREFIX          "_vgnU_"
    104 #define VG_NOTIFY_ON_LOAD_PREFIX_LEN      6
    105 
    106 
    107 //--------------------------------------------------------------------
    108 // Function wrapping
    109 //--------------------------------------------------------------------
    110 
    111 // This is currently not working(?) --njn
    112 
    113 /* Wrapping machinery */
    114 //enum return_type {
    115   //   RT_RETURN,
    116    //   RT_LONGJMP,
    117    //   RT_EXIT,
    118    //};
    119 //
    120 //typedef struct _FuncWrapper FuncWrapper;
    121 //struct _FuncWrapper {
    122   //   void *(*before)(va_list args);
    123   //   void  (*after) (void *nonce, enum return_type, Word retval);
    124   //};
    125 //
    126 //extern void VG_(wrap_function)(Addr eip, const FuncWrapper *wrapper);
    127 //extern const FuncWrapper *VG_(is_wrapped)(Addr eip);
    128 //extern Bool VG_(is_wrapper_return)(Addr eip);
    129 
    130 /* Primary interface for adding wrappers for client-side functions. */
    131 //extern CodeRedirect *VG_(add_wrapper)(const Char *from_lib, const Char *from_sym,
    132 //				      const FuncWrapper *wrapper);
    133 //
    134 //extern Bool VG_(is_resolved)(const CodeRedirect *redir);
    135 
    136 #endif   // __PUB_CORE_REDIR_H
    137 
    138 /*--------------------------------------------------------------------*/
    139 /*--- end                                                          ---*/
    140 /*--------------------------------------------------------------------*/
    141