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Add some debug support code to try to catch future mistakes in the area of

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input functions that include garbage bytes in their results.  Provide a
compile-time option RANDOMIZE_ALLOCATED_MEMORY to make palloc fill returned
blocks with variable contents.  This option also makes the parser perform
conversions of literal constants twice and compare the results, emitting a
WARNING if they don't match.  (This is the code I used to catch the input
function bugs fixed in the previous commit.)  For the moment, I've set it
to be activated automatically by --enable-cassert.
This commit is contained in:
Tom Lane
2008-04-11 22:54:23 +00:00
parent c846f7ca8a
commit 65c3d05e18
3 changed files with 98 additions and 14 deletions
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53
src/backend/utils/mmgr/aset.c
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@@ -11,7 +11,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/mmgr/aset.c,v 1.76 2008/01/01 19:45:55 momjian Exp $
* $PostgreSQL: pgsql/src/backend/utils/mmgr/aset.c,v 1.77 2008/04/11 22:54:23 tgl Exp $
*
* NOTE:
* This is a new (Feb. 05, 1999) implementation of the allocation set
@@ -282,6 +282,32 @@ AllocSetFreeIndex(Size size)
return idx;
}
#ifdef RANDOMIZE_ALLOCATED_MEMORY
/*
* Fill a just-allocated piece of memory with "random" data. It's not really
* very random, just a repeating sequence with a length that's prime. What
* we mainly want out of it is to have a good probability that two palloc's
* of the same number of bytes start out containing different data.
*/
static void
randomize_mem(char *ptr, size_t size)
{
static int save_ctr = 1;
int ctr;
ctr = save_ctr;
while (size-- > 0)
{
*ptr++ = ctr;
if (++ctr > 251)
ctr = 1;
}
save_ctr = ctr;
}
#endif /* RANDOMIZE_ALLOCATED_MEMORY */
/*
* Public routines
@@ -552,6 +578,10 @@ AllocSetAlloc(MemoryContext context, Size size)
if (size < chunk_size)
((char *) AllocChunkGetPointer(chunk))[size] = 0x7E;
#endif
#ifdef RANDOMIZE_ALLOCATED_MEMORY
/* fill the allocated space with junk */
randomize_mem((char *) AllocChunkGetPointer(chunk), size);
#endif
/*
* Stick the new block underneath the active allocation block, so that
@@ -596,6 +626,10 @@ AllocSetAlloc(MemoryContext context, Size size)
if (size < chunk->size)
((char *) AllocChunkGetPointer(chunk))[size] = 0x7E;
#endif
#ifdef RANDOMIZE_ALLOCATED_MEMORY
/* fill the allocated space with junk */
randomize_mem((char *) AllocChunkGetPointer(chunk), size);
#endif
/* isReset must be false already */
Assert(!set->isReset);
@@ -752,6 +786,10 @@ AllocSetAlloc(MemoryContext context, Size size)
if (size < chunk->size)
((char *) AllocChunkGetPointer(chunk))[size] = 0x7E;
#endif
#ifdef RANDOMIZE_ALLOCATED_MEMORY
/* fill the allocated space with junk */
randomize_mem((char *) AllocChunkGetPointer(chunk), size);
#endif
set->isReset = false;
@@ -864,6 +902,13 @@ AllocSetRealloc(MemoryContext context, void *pointer, Size size)
if (oldsize >= size)
{
#ifdef MEMORY_CONTEXT_CHECKING
#ifdef RANDOMIZE_ALLOCATED_MEMORY
/* We can only fill the extra space if we know the prior request */
if (size > chunk->requested_size)
randomize_mem((char *) AllocChunkGetPointer(chunk) + chunk->requested_size,
size - chunk->requested_size);
#endif
chunk->requested_size = size;
/* set mark to catch clobber of "unused" space */
if (size < oldsize)
@@ -921,6 +966,12 @@ AllocSetRealloc(MemoryContext context, void *pointer, Size size)
chunk->size = chksize;
#ifdef MEMORY_CONTEXT_CHECKING
#ifdef RANDOMIZE_ALLOCATED_MEMORY
/* We can only fill the extra space if we know the prior request */
randomize_mem((char *) AllocChunkGetPointer(chunk) + chunk->requested_size,
size - chunk->requested_size);
#endif
chunk->requested_size = size;
/* set mark to catch clobber of "unused" space */
if (size < chunk->size)