Files
bitcoin/src/support/cleanse.cpp
MeshCollider 1a445343f6 scripted-diff: Replace #include "" with #include <> (ryanofsky)
-BEGIN VERIFY SCRIPT-
for f in \
  src/*.cpp \
  src/*.h \
  src/bench/*.cpp \
  src/bench/*.h \
  src/compat/*.cpp \
  src/compat/*.h \
  src/consensus/*.cpp \
  src/consensus/*.h \
  src/crypto/*.cpp \
  src/crypto/*.h \
  src/crypto/ctaes/*.h \
  src/policy/*.cpp \
  src/policy/*.h \
  src/primitives/*.cpp \
  src/primitives/*.h \
  src/qt/*.cpp \
  src/qt/*.h \
  src/qt/test/*.cpp \
  src/qt/test/*.h \
  src/rpc/*.cpp \
  src/rpc/*.h \
  src/script/*.cpp \
  src/script/*.h \
  src/support/*.cpp \
  src/support/*.h \
  src/support/allocators/*.h \
  src/test/*.cpp \
  src/test/*.h \
  src/wallet/*.cpp \
  src/wallet/*.h \
  src/wallet/test/*.cpp \
  src/wallet/test/*.h \
  src/zmq/*.cpp \
  src/zmq/*.h
do
  base=${f%/*}/ relbase=${base#src/} sed -i "s:#include \"\(.*\)\"\(.*\):if test -e \$base'\\1'; then echo \"#include <\"\$relbase\"\\1>\\2\"; else echo \"#include <\\1>\\2\"; fi:e" $f
done
-END VERIFY SCRIPT-
2017-11-16 08:23:01 +13:00

40 lines
1.4 KiB
C++

// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2015 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include <support/cleanse.h>
#include <cstring>
/* Compilers have a bad habit of removing "superfluous" memset calls that
* are trying to zero memory. For example, when memset()ing a buffer and
* then free()ing it, the compiler might decide that the memset is
* unobservable and thus can be removed.
*
* Previously we used OpenSSL which tried to stop this by a) implementing
* memset in assembly on x86 and b) putting the function in its own file
* for other platforms.
*
* This change removes those tricks in favour of using asm directives to
* scare the compiler away. As best as our compiler folks can tell, this is
* sufficient and will continue to be so.
*
* Adam Langley <agl@google.com>
* Commit: ad1907fe73334d6c696c8539646c21b11178f20f
* BoringSSL (LICENSE: ISC)
*/
void memory_cleanse(void *ptr, size_t len)
{
std::memset(ptr, 0, len);
/* As best as we can tell, this is sufficient to break any optimisations that
might try to eliminate "superfluous" memsets. If there's an easy way to
detect memset_s, it would be better to use that. */
#if defined(_MSC_VER)
__asm;
#else
__asm__ __volatile__("" : : "r"(ptr) : "memory");
#endif
}