| |
| /*--------------------------------------------------------------------*/ |
| /*--- Redirections, etc. pub_tool_redir.h ---*/ |
| /*--------------------------------------------------------------------*/ |
| |
| /* |
| This file is part of Valgrind, a dynamic binary instrumentation |
| framework. |
| |
| Copyright (C) 2000-2005 Julian Seward |
| jseward@acm.org |
| |
| This program is free software; you can redistribute it and/or |
| modify it under the terms of the GNU General Public License as |
| published by the Free Software Foundation; either version 2 of the |
| License, or (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program; if not, write to the Free Software |
| Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307, USA. |
| |
| The GNU General Public License is contained in the file COPYING. |
| */ |
| |
| #ifndef __PUB_TOOL_REDIR_H |
| #define __PUB_TOOL_REDIR_H |
| |
| /* The following macros facilitate function replacement, which is one form |
| of code replacement. |
| |
| The general idea is: you can write a function like this: |
| |
| ret_type VG_REPLACE_FUNCTION(zEncodedSoname, fnname) ( ... args ... ) |
| { |
| ... body ... |
| } |
| |
| zEncodedSoname should be a Z-encoded soname (see below for Z-encoding |
| details) and fnname should be an unencoded fn name. The resulting name is |
| |
| _vgi_zEncodedSoname_fnname |
| |
| The "_vgi_" is a prefix that gets discarded upon decoding. |
| |
| When it sees this name, the core's symbol-table reading machinery |
| and redirection machinery will conspire to cause calls to the function |
| 'fnname' in object with soname 'zEncodedSoname' to actually be routed to |
| the function written here. We use this below to define dozens of |
| replacements of malloc, free, etc. |
| |
| The soname must be a Z-encoded bit of text because sonames can |
| contain dots etc which are not valid symbol names. But don't Z-encode |
| the function name, since it will already be a valid symbol name, and the |
| Z-encoding might screw up the C++ demangling. |
| |
| Note that the soname can contain '*' as a wildcard meaning "match |
| anything". |
| |
| Note also that the replacement function should probably (must be?) in |
| client space, so it runs on the simulated CPU. So it must be in |
| either vgpreload_<tool>.so or vgpreload_core.so. It also only works |
| with functions in shared objects, I think. |
| |
| It is important that the Z-encoded soname contains no unencoded |
| underscores, since the intercept-handlers in vg_symtab2.c detect |
| the end of the soname by looking for the first trailing underscore. |
| |
| Z-encoding details: the scheme is like GHC's. It is just about |
| readable enough to make a preprocessor unnecessary. First the "_vgi_" |
| prefix is added, and then the following characters are transformed. |
| |
| * --> Za ('a' for "asterisk") |
| + --> Zp |
| : --> Zc |
| . --> Zd |
| _ --> Zu |
| - --> Zh ('h' for "hyphen") |
| (space) --> Zs |
| Z --> ZZ |
| |
| Everything else is left unchanged. |
| */ |
| |
| #define VG_REPLACE_FUNCTION(soname, fnname) _vgi_##soname##_##fnname |
| #define VG_REPLACE_FUNCTION_PREFIX "_vgi_" |
| #define VG_REPLACE_FUNCTION_PREFIX_LEN 5 |
| |
| #endif // __PUB_TOOL_REDIR_H |
| |
| /*--------------------------------------------------------------------*/ |
| /*--- end ---*/ |
| /*--------------------------------------------------------------------*/ |