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/*
Unix SMB/CIFS implementation.
Samba utility functions
Copyright (C) Martin Pool 2003
Copyright (C) Andrew Bartlett 2003
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 3 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, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
#ifdef DEVELOPER
const char *global_clobber_region_function;
unsigned int global_clobber_region_line;
#endif
/**
* In developer builds, clobber a region of memory.
*
* If we think a string buffer is longer than it really is, this ought
* to make the failure obvious, by segfaulting (if in the heap) or by
* killing the return address (on the stack), or by trapping under a
* memory debugger.
*
* This is meant to catch possible string overflows, even if the
* actual string copied is not big enough to cause an overflow.
*
* In addition, under Valgrind the buffer is marked as uninitialized.
**/
void clobber_region(const char *fn, unsigned int line, char *dest, size_t len)
{
#ifdef DEVELOPER
global_clobber_region_function = fn;
global_clobber_region_line = line;
/* F1 is odd and 0xf1f1f1f1 shouldn't be a valid pointer */
memset(dest, 0xF1, len);
#ifdef VALGRIND
/* Even though we just wrote to this, from the application's
* point of view it is not initialized.
*
* (This is not redundant with the clobbering above. The
* marking might not actually take effect if we're not running
* under valgrind.) */
#if defined(VALGRIND_MAKE_MEM_UNDEFINED)
VALGRIND_MAKE_MEM_UNDEFINED(dest, len);
#elif defined(VALGRIND_MAKE_WRITABLE)
VALGRIND_MAKE_WRITABLE(dest, len);
#endif
#endif /* VALGRIND */
#endif /* DEVELOPER */
}
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