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HashAllocator: poison freed blocks #366

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HashAllocator: poison freed blocks #366

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3 changes: 3 additions & 0 deletions config-linuxmodule.h.in
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Original file line number Diff line number Diff line change
Expand Up @@ -178,6 +178,9 @@
/* Define to 1 if Linux defines the type 'uintptr_t'. */
#undef HAVE_UINTPTR_T_LINUXMODULE

/* Define to 1 to enable poisoning of freed HashAllocator blocks. */
#undef HAVE_HASH_ALLOCATOR_POISONING

/* The size of a `click_jiffies_t', as computed by sizeof. */
#define SIZEOF_CLICK_JIFFIES_T SIZEOF_LONG

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3 changes: 3 additions & 0 deletions config-userlevel.h.in
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Expand Up @@ -223,6 +223,9 @@
/* Define if you have the <valgrind/memcheck.h> header file. */
#undef HAVE_VALGRIND_MEMCHECK_H

/* Define to 1 to enable poisoning of freed HashAllocator blocks. */
#undef HAVE_HASH_ALLOCATOR_POISONING

/* Define if you have the vsnprintf function. */
#undef HAVE_VSNPRINTF

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5 changes: 5 additions & 0 deletions configure.in
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Expand Up @@ -1120,6 +1120,11 @@ if test "$value" != 0; then
AC_DEFINE_UNQUOTED([CLICK_DEBUG_SCHEDULING], [$value], [Define to enable debugging support for Click scheduling.])
fi

AC_ARG_ENABLE(hash-allocator-poisoning, [ --enable-hash-allocator-poisoning enable HashAllocator block poisoning], :, enable_hash_allocator_poisoning=no)
if test $enable_hash_allocator_poisoning = yes; then
AC_DEFINE(HAVE_HASH_ALLOCATOR_POISONING)
fi


dnl use Intel-specific machine instructions

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8 changes: 8 additions & 0 deletions include/click/hashallocator.hh
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Expand Up @@ -23,6 +23,11 @@ class HashAllocator { public:

private:

#if HAVE_HASH_ALLOCATOR_POISONING
// Freed blocks are poisoned with this byte value.
static const uint8_t poison_byte = 0x0d;
#endif

struct link {
link *next;
};
Expand Down Expand Up @@ -91,6 +96,9 @@ inline void *HashAllocator::allocate()
inline void HashAllocator::deallocate(void *p)
{
if (p) {
#if HAVE_HASH_ALLOCATOR_POISONING
memset(p, poison_byte, _size);
#endif
reinterpret_cast<link *>(p)->next = _free;
_free = reinterpret_cast<link *>(p);
#ifdef VALGRIND_MEMPOOL_FREE
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