1 files changed, 930 insertions, 0 deletions

diff --git a/src/common/ef/efence.cpp b/src/common/ef/efence.cpp
new file mode 100644
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--- /dev/null
+++ b/src/common/ef/efence.cpp
@@ -0,0 +1,930 @@
+/*
+ * Electric Fence - Red-Zone memory allocator.
+ * Bruce Perens, 1988, 1993
+ * 
+ * This is a special version of malloc() and company for debugging software
+ * that is suspected of overrunning or underrunning the boundaries of a
+ * malloc buffer, or touching free memory.
+ *
+ * It arranges for each malloc buffer to be followed (or preceded)
+ * in the address space by an inaccessable virtual memory page,
+ * and for free memory to be inaccessable. If software touches the
+ * inaccessable page, it will get an immediate segmentation
+ * fault. It is then trivial to uncover the offending code using a debugger.
+ *
+ * An advantage of this product over most malloc debuggers is that this one
+ * detects reading out of bounds as well as writing, and this one stops on
+ * the exact instruction that causes the error, rather than waiting until the
+ * next boundary check.
+ *
+ * There is one product that debugs malloc buffer overruns
+ * better than Electric Fence: "Purify" from Purify Systems, and that's only
+ * a small part of what Purify does. I'm not affiliated with Purify, I just
+ * respect a job well done.
+ *
+ * This version of malloc() should not be linked into production software,
+ * since it tremendously increases the time and memory overhead of malloc().
+ * Each malloc buffer will consume a minimum of two virtual memory pages,
+ * this is 16 kilobytes on many systems. On some systems it will be necessary
+ * to increase the amount of swap space in order to debug large programs that
+ * perform lots of allocation, because of the per-buffer overhead.
+ */
+#include "efence.h"
+#include <stdlib.h>
+#include <unistd.h>
+#include <memory.h>
+#include <string.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdint.h>
+
+
+extern C_LINKAGE void * ef_malloc(size_t size);
+extern C_LINKAGE void ef_free(void * address);
+extern C_LINKAGE void * ef_memalign(size_t alignment, size_t userSize);
+extern C_LINKAGE void * ef_calloc(size_t nelem, size_t elsize);
+extern C_LINKAGE void * ef_valloc (size_t size);
+extern C_LINKAGE void * ef_realloc(void * oldBuffer, size_t newSize);
+extern C_LINKAGE void ef_init(void);
+
+
+
+
+
+#ifdef	malloc
+#undef	malloc
+#endif
+
+#ifdef	calloc
+#undef	calloc
+#endif
+
+static const char	version[] = "\n  Electric Fence 2.1"
+ " Copyright (C) 1987-1998 Bruce Perens.\n";
+
+/*
+ * MEMORY_CREATION_SIZE is the amount of memory to get from the operating
+ * system at one time. We'll break that memory down into smaller pieces for
+ * malloc buffers. One megabyte is probably a good value.
+ */
+#define			MEMORY_CREATION_SIZE	10* 1024 * 1024
+
+/*
+ * Enum Mode indicates the status of a malloc buffer.
+ */
+enum _Mode {
+	NOT_IN_USE = 0,	/* Available to represent a malloc buffer. */
+	FREE,		/* A free buffer. */
+	ALLOCATED,	/* A buffer that is in use. */
+	PROTECTED,	/* A freed buffer that can not be allocated again. */
+	INTERNAL_USE	/* A buffer used internally by malloc(). */
+};
+typedef enum _Mode	Mode;
+
+/*
+ * Struct Slot contains all of the information about a malloc buffer except
+ * for the contents of its memory.
+ */
+struct _Slot {
+	void *		userAddress;
+	void *		internalAddress;
+	size_t		userSize;
+	size_t		internalSize;
+	Mode		mode;
+};
+typedef struct _Slot	Slot;
+
+ /*
+ * EF_DISABLE_BANNER is a global variable used to control whether
+ * Electric Fence prints its usual startup message.  If the value is
+ * -1, it will be set from the environment default to 0 at run time.
+ */
+int            EF_DISABLE_BANNER = 1;
+
+
+/*
+ * EF_ALIGNMENT is a global variable used to control the default alignment
+ * of buffers returned by malloc(), calloc(), and realloc(). It is all-caps
+ * so that its name matches the name of the environment variable that is used
+ * to set it. This gives the programmer one less name to remember.
+ * If the value is -1, it will be set from the environment or sizeof(int)
+ * at run time.
+ */
+int		EF_ALIGNMENT = 8;
+
+/*
+ * EF_PROTECT_FREE is a global variable used to control the disposition of
+ * memory that is released using free(). It is all-caps so that its name
+ * matches the name of the environment variable that is used to set it.
+ * If its value is greater non-zero, memory released by free is made
+ * inaccessable and never allocated again. Any software that touches free
+ * memory will then get a segmentation fault. If its value is zero, freed
+ * memory will be available for reallocation, but will still be inaccessable
+ * until it is reallocated.
+ * If the value is -1, it will be set from the environment or to 0 at run-time.
+ */
+int		EF_PROTECT_FREE = -1;
+
+/*
+ * EF_PROTECT_BELOW is used to modify the behavior of the allocator. When
+ * its value is non-zero, the allocator will place an inaccessable page
+ * immediately _before_ the malloc buffer in the address space, instead
+ * of _after_ it. Use this to detect malloc buffer under-runs, rather than
+ * over-runs. It won't detect both at the same time, so you should test your
+ * software twice, once with this value clear, and once with it set.
+ * If the value is -1, it will be set from the environment or to zero at
+ * run-time
+ */
+int		EF_PROTECT_BELOW = -1;
+
+/*
+ * EF_ALLOW_MALLOC_0 is set if Electric Fence is to allow malloc(0). I
+ * trap malloc(0) by default because it is a common source of bugs.
+ */
+int		EF_ALLOW_MALLOC_0 = 0;
+
+/*
+ * EF_FREE_WIPES is set if Electric Fence is to wipe the memory content
+ * of freed blocks.  This makes it easier to check if memory is freed or
+ * not
+ */
+int            EF_FREE_WIPES = 1;
+
+
+static int malloc_init =0;
+/*
+
+ * allocationList points to the array of slot structures used to manage the
+ * malloc arena.
+ */
+static Slot *		allocationList = 0;
+
+/*
+ * allocationListSize is the size of the allocation list. This will always
+ * be a multiple of the page size.
+ */
+static size_t		allocationListSize = 0;
+
+/*
+ * slotCount is the number of Slot structures in allocationList.
+ */
+static size_t		slotCount = 0;
+
+/*
+ * unUsedSlots is the number of Slot structures that are currently available
+ * to represent new malloc buffers. When this number gets too low, we will
+ * create new slots.
+ */
+static size_t		unUsedSlots = 0;
+
+/*
+ * slotsPerPage is the number of slot structures that fit in a virtual
+ * memory page.
+ */
+static size_t		slotsPerPage = 0;
+
+/*
+ * internalUse is set when allocating and freeing the allocatior-internal
+ * data structures.
+ */
+static int		internalUse = 0;
+
+/*
+ * noAllocationListProtection is set to tell malloc() and free() not to
+ * manipulate the protection of the allocation list. This is only set in
+ * realloc(), which does it to save on slow system calls, and in
+ * allocateMoreSlots(), which does it because it changes the allocation list.
+ */
+static int		noAllocationListProtection = 0;
+
+/*
+ * bytesPerPage is set at run-time to the number of bytes per virtual-memory
+ * page, as returned by Page_Size().
+ */
+static size_t		bytesPerPage = 0;
+
+ /*
+ * mutex to enable multithreaded operation
+ */
+static pthread_mutex_t mutex ;
+
+
+static void lock() {
+    /* reentrant mutex -see init  */
+    pthread_mutex_lock(&mutex);
+}
+
+static void unlock() {
+    pthread_mutex_unlock(&mutex);
+}
+
+
+
+/*
+ * internalError is called for those "shouldn't happen" errors in the
+ * allocator.
+ */
+static void
+internalError(void)
+{
+	EF_Abort("Internal error in allocator.");
+}
+
+/*
+ * initialize sets up the memory allocation arena and the run-time
+ * configuration information.
+ */
+static void
+initialize(void)
+{
+	size_t	size = MEMORY_CREATION_SIZE;
+	size_t	slack;
+	char *	string;
+	Slot *	slot;
+
+       if ( EF_DISABLE_BANNER == -1 ) {
+               if ( (string = getenv("EF_DISABLE_BANNER")) != 0 )
+                       EF_DISABLE_BANNER = atoi(string);
+               else
+                       EF_DISABLE_BANNER = 0;
+       }
+
+       if ( EF_DISABLE_BANNER == 0 )
+               EF_Print(version);
+
+	/*
+	 * Import the user's environment specification of the default
+	 * alignment for malloc(). We want that alignment to be under
+	 * user control, since smaller alignment lets us catch more bugs,
+	 * however some software will break if malloc() returns a buffer
+	 * that is not word-aligned.
+	 *
+	 * I would like
+	 * alignment to be zero so that we could catch all one-byte
+	 * overruns, however if malloc() is asked to allocate an odd-size
+	 * buffer and returns an address that is not word-aligned, or whose
+	 * size is not a multiple of the word size, software breaks.
+	 * This was the case with the Sun string-handling routines,
+	 * which can do word fetches up to three bytes beyond the end of a
+	 * string. I handle this problem in part by providing
+	 * byte-reference-only versions of the string library functions, but
+	 * there are other functions that break, too. Some in X Windows, one
+	 * in Sam Leffler's TIFF library, and doubtless many others.
+	 */
+	if ( EF_ALIGNMENT == -1 ) {
+		if ( (string = getenv("EF_ALIGNMENT")) != 0 )
+			EF_ALIGNMENT = (size_t)atoi(string);
+		else
+			EF_ALIGNMENT = sizeof(int);
+	}
+
+	/*
+	 * See if the user wants to protect the address space below a buffer,
+	 * rather than that above a buffer.
+	 */
+	if ( EF_PROTECT_BELOW == -1 ) {
+		if ( (string = getenv("EF_PROTECT_BELOW")) != 0 )
+			EF_PROTECT_BELOW = (atoi(string) != 0);
+		else
+			EF_PROTECT_BELOW = 0;
+	}
+
+	/*
+	 * See if the user wants to protect memory that has been freed until
+	 * the program exits, rather than until it is re-allocated.
+	 */
+	if ( EF_PROTECT_FREE == -1 ) {
+		if ( (string = getenv("EF_PROTECT_FREE")) != 0 )
+			EF_PROTECT_FREE = (atoi(string) != 0);
+		else
+			EF_PROTECT_FREE = 0;
+	}
+
+	/*
+	 * See if the user wants to allow malloc(0).
+	 */
+	if ( EF_ALLOW_MALLOC_0 == -1 ) {
+		if ( (string = getenv("EF_ALLOW_MALLOC_0")) != 0 )
+			EF_ALLOW_MALLOC_0 = (atoi(string) != 0);
+		else
+			EF_ALLOW_MALLOC_0 = 0;
+	}
+
+	/*
+	 * See if the user wants us to wipe out freed memory.
+	 */
+	if ( EF_FREE_WIPES == -1 ) {
+	        if ( (string = getenv("EF_FREE_WIPES")) != 0 )
+	                EF_FREE_WIPES = (atoi(string) != 0);
+	        else
+	                EF_FREE_WIPES = 0;
+	}
+
+	/*
+	 * Get the run-time configuration of the virtual memory page size.
+ 	 */
+	bytesPerPage = Page_Size();
+
+	/*
+	 * Figure out how many Slot structures to allocate at one time.
+	 */
+	slotCount = slotsPerPage = bytesPerPage / sizeof(Slot);
+	allocationListSize = bytesPerPage;
+
+	if ( allocationListSize > size )
+		size = allocationListSize;
+
+	if ( (slack = size % bytesPerPage) != 0 )
+		size += bytesPerPage - slack;
+
+	/*
+	 * Allocate memory, and break it up into two malloc buffers. The
+	 * first buffer will be used for Slot structures, the second will
+	 * be marked free.
+	 */
+	slot = allocationList = (Slot *)Page_Create(size);
+	memset((char *)allocationList, 0, allocationListSize);
+
+	slot[0].internalSize = slot[0].userSize = allocationListSize;
+	slot[0].internalAddress = slot[0].userAddress = allocationList;
+	slot[0].mode = INTERNAL_USE;
+	if ( size > allocationListSize ) {
+		slot[1].internalAddress = slot[1].userAddress
+		 = ((char *)slot[0].internalAddress) + slot[0].internalSize;
+		slot[1].internalSize
+		 = slot[1].userSize = size - slot[0].internalSize;
+		slot[1].mode = FREE;
+	}
+
+	/*
+	 * Deny access to the free page, so that we will detect any software
+	 * that treads upon free memory.
+	 */
+	Page_DenyAccess(slot[1].internalAddress, slot[1].internalSize);
+
+	/*
+	 * Account for the two slot structures that we've used.
+	 */
+	unUsedSlots = slotCount - 2;
+}
+
+/*
+ * allocateMoreSlots is called when there are only enough slot structures
+ * left to support the allocation of a single malloc buffer.
+ */
+static void
+allocateMoreSlots(void)
+{
+	size_t	newSize = allocationListSize + bytesPerPage;
+	void *	newAllocation;
+	void *	oldAllocation = allocationList;
+
+	Page_AllowAccess(allocationList, allocationListSize);
+	noAllocationListProtection = 1;
+	internalUse = 1;
+
+	newAllocation = ef_malloc(newSize);
+	memcpy(newAllocation, allocationList, allocationListSize);
+	memset(&(((char *)newAllocation)[allocationListSize]), 0, bytesPerPage);
+
+	allocationList = (Slot *)newAllocation;
+	allocationListSize = newSize;
+	slotCount += slotsPerPage;
+	unUsedSlots += slotsPerPage;
+
+	ef_free(oldAllocation);
+
+	/*
+	 * Keep access to the allocation list open at this point, because
+	 * I am returning to memalign(), which needs that access.
+ 	 */
+	noAllocationListProtection = 0;
+	internalUse = 0;
+}
+
+/*
+ * This is the memory allocator. When asked to allocate a buffer, allocate
+ * it in such a way that the end of the buffer is followed by an inaccessable
+ * memory page. If software overruns that buffer, it will touch the bad page
+ * and get an immediate segmentation fault. It's then easy to zero in on the
+ * offending code with a debugger.
+ *
+ * There are a few complications. If the user asks for an odd-sized buffer,
+ * we would have to have that buffer start on an odd address if the byte after
+ * the end of the buffer was to be on the inaccessable page. Unfortunately,
+ * there is lots of software that asks for odd-sized buffers and then
+ * requires that the returned address be word-aligned, or the size of the
+ * buffer be a multiple of the word size. An example are the string-processing
+ * functions on Sun systems, which do word references to the string memory
+ * and may refer to memory up to three bytes beyond the end of the string.
+ * For this reason, I take the alignment requests to memalign() and valloc()
+ * seriously, and 
+ * 
+ * Electric Fence wastes lots of memory. I do a best-fit allocator here
+ * so that it won't waste even more. It's slow, but thrashing because your
+ * working set is too big for a system's RAM is even slower. 
+ */
+extern C_LINKAGE void *
+ef_memalign(size_t alignment, size_t userSize)
+{
+	register Slot *	slot;
+	register size_t	count;
+	Slot *		fullSlot = 0;
+	Slot *		emptySlots[2];
+	size_t		internalSize;
+	size_t		slack;
+	char *		address;
+
+
+	if ( userSize == 0 && !EF_ALLOW_MALLOC_0 )
+		EF_Abort("Allocating 0 bytes, probably a bug.");
+
+	/*
+	 * If EF_PROTECT_BELOW is set, all addresses returned by malloc()
+	 * and company will be page-aligned.
+ 	 */
+	if ( !EF_PROTECT_BELOW && alignment > 1 ) {
+		if ( (slack = userSize % alignment) != 0 )
+			userSize += alignment - slack;
+	}
+
+	/*
+	 * The internal size of the buffer is rounded up to the next page-size
+	 * boudary, and then we add another page's worth of memory for the
+	 * dead page.
+	 */
+	internalSize = userSize + bytesPerPage;
+	if ( (slack = internalSize % bytesPerPage) != 0 )
+		internalSize += bytesPerPage - slack;
+
+	/*
+	 * These will hold the addresses of two empty Slot structures, that
+	 * can be used to hold information for any memory I create, and any
+	 * memory that I mark free.
+	 */
+	emptySlots[0] = 0;
+	emptySlots[1] = 0;
+
+	/*
+	 * The internal memory used by the allocator is currently
+	 * inaccessable, so that errant programs won't scrawl on the
+	 * allocator's arena. I'll un-protect it here so that I can make
+	 * a new allocation. I'll re-protect it before I return.
+ 	 */
+	if ( !noAllocationListProtection )
+		Page_AllowAccess(allocationList, allocationListSize);
+
+	/*
+	 * If I'm running out of empty slots, create some more before
+	 * I don't have enough slots left to make an allocation.
+	 */
+	if ( !internalUse && unUsedSlots < 7 ) {
+		allocateMoreSlots();
+	}
+	
+	/*
+	 * Iterate through all of the slot structures. Attempt to find a slot
+	 * containing free memory of the exact right size. Accept a slot with
+	 * more memory than we want, if the exact right size is not available.
+	 * Find two slot structures that are not in use. We will need one if
+	 * we split a buffer into free and allocated parts, and the second if
+	 * we have to create new memory and mark it as free.
+	 *
+	 */
+	
+	for ( slot = allocationList, count = slotCount ; count > 0; count-- ) {
+		if ( slot->mode == FREE
+		 && slot->internalSize >= internalSize ) {
+			if ( !fullSlot
+			 ||slot->internalSize < fullSlot->internalSize){
+				fullSlot = slot;
+				if ( slot->internalSize == internalSize
+				 && emptySlots[0] )
+					break;	/* All done, */
+			}
+		}
+		else if ( slot->mode == NOT_IN_USE ) {
+			if ( !emptySlots[0] )
+				emptySlots[0] = slot;
+			else if ( !emptySlots[1] )
+				emptySlots[1] = slot;
+			else if ( fullSlot
+			 && fullSlot->internalSize == internalSize )
+				break;	/* All done. */
+		}
+		slot++;
+	}
+	if ( !emptySlots[0] )
+		internalError();
+
+	if ( !fullSlot ) {
+		/*
+		 * I get here if I haven't been able to find a free buffer
+		 * with all of the memory I need. I'll have to create more
+		 * memory. I'll mark it all as free, and then split it into
+		 * free and allocated portions later.
+		 */
+		size_t	chunkSize = MEMORY_CREATION_SIZE;
+
+		if ( !emptySlots[1] )
+			internalError();
+
+		if ( chunkSize < internalSize )
+			chunkSize = internalSize;
+
+		if ( (slack = chunkSize % bytesPerPage) != 0 )
+			chunkSize += bytesPerPage - slack;
+
+		/* Use up one of the empty slots to make the full slot. */
+		fullSlot = emptySlots[0];
+		emptySlots[0] = emptySlots[1];
+		fullSlot->internalAddress = Page_Create(chunkSize);
+		fullSlot->internalSize = chunkSize;
+		fullSlot->mode = FREE;
+		unUsedSlots--;
+	}
+
+	/*
+	 * If I'm allocating memory for the allocator's own data structures,
+	 * mark it INTERNAL_USE so that no errant software will be able to
+	 * free it.
+	 */
+	if ( internalUse )
+		fullSlot->mode = INTERNAL_USE;
+	else
+		fullSlot->mode = ALLOCATED;
+
+	/*
+	 * If the buffer I've found is larger than I need, split it into
+	 * an allocated buffer with the exact amount of memory I need, and
+	 * a free buffer containing the surplus memory.
+	 */
+	if ( fullSlot->internalSize > internalSize ) {
+		emptySlots[0]->internalSize
+		 = fullSlot->internalSize - internalSize;
+		emptySlots[0]->internalAddress
+		 = ((char *)fullSlot->internalAddress) + internalSize;
+		emptySlots[0]->mode = FREE;
+		fullSlot->internalSize = internalSize;
+		unUsedSlots--;
+	}
+
+	if ( !EF_PROTECT_BELOW ) {
+		/*
+		 * Arrange the buffer so that it is followed by an inaccessable
+		 * memory page. A buffer overrun that touches that page will
+		 * cause a segmentation fault.
+		 */
+		address = (char *)fullSlot->internalAddress;
+
+		/* Set up the "live" page. */
+		if ( internalSize - bytesPerPage > 0 )
+				Page_AllowAccess(
+				 fullSlot->internalAddress
+				,internalSize - bytesPerPage);
+			
+		address += internalSize - bytesPerPage;
+
+		/* Set up the "dead" page. */
+		Page_DenyAccess(address, bytesPerPage);
+
+		/* Figure out what address to give the user. */
+		address -= userSize;
+	}
+	else {	/* EF_PROTECT_BELOW != 0 */
+		/*
+		 * Arrange the buffer so that it is preceded by an inaccessable
+		 * memory page. A buffer underrun that touches that page will
+		 * cause a segmentation fault.
+		 */
+		address = (char *)fullSlot->internalAddress;
+
+		/* Set up the "dead" page. */
+		Page_DenyAccess(address, bytesPerPage);
+			
+		address += bytesPerPage;
+
+		/* Set up the "live" page. */
+		if ( internalSize - bytesPerPage > 0 )
+			Page_AllowAccess(address, internalSize - bytesPerPage);
+	}
+
+	fullSlot->userAddress = address;
+	fullSlot->userSize = userSize;
+
+	/*
+	 * Make the pool's internal memory inaccessable, so that the program
+	 * being debugged can't stomp on it.
+	 */
+	if ( !internalUse )
+		Page_DenyAccess(allocationList, allocationListSize);
+
+	return address;
+}
+
+/*
+ * Find the slot structure for a user address.
+ */
+static Slot *
+slotForUserAddress(void * address)
+{
+	register Slot *	slot = allocationList;
+	register size_t	count = slotCount;
+	
+	for ( ; count > 0; count-- ) {
+		if ( slot->userAddress == address )
+			return slot;
+		slot++;
+	}
+
+	return 0;
+}
+
+/*
+ * Find the slot structure for an internal address.
+ */
+static Slot *
+slotForInternalAddress(void * address)
+{
+	register Slot *	slot = allocationList;
+	register size_t	count = slotCount;
+	
+	for ( ; count > 0; count-- ) {
+		if ( slot->internalAddress == address )
+			return slot;
+		slot++;
+	}
+	return 0;
+}
+
+/*
+ * Given the internal address of a buffer, find the buffer immediately
+ * before that buffer in the address space. This is used by free() to
+ * coalesce two free buffers into one.
+ */
+static Slot *
+slotForInternalAddressPreviousTo(void * address)
+{
+	register Slot *	slot = allocationList;
+	register size_t	count = slotCount;
+	
+	for ( ; count > 0; count-- ) {
+		if ( ((char *)slot->internalAddress)
+		 + slot->internalSize == address )
+			return slot;
+		slot++;
+	}
+	return 0;
+}
+
+extern C_LINKAGE void
+ef_free(void * address)
+{
+	Slot *	slot;
+	Slot *	previousSlot = 0;
+	Slot *	nextSlot = 0;
+
+    //printf(" ::free %p \n",address);
+    lock();
+
+    if ( address == 0 ) {
+            unlock();
+            return;
+    }
+
+	if ( allocationList == 0 )
+		EF_Abort("free() called before first malloc().");
+
+	if ( !noAllocationListProtection )
+		Page_AllowAccess(allocationList, allocationListSize);
+
+	slot = slotForUserAddress(address);
+
+	if ( !slot )
+		EF_Abort("free(%a): address not from malloc().", address);
+
+	if ( slot->mode != ALLOCATED ) {
+		if ( internalUse && slot->mode == INTERNAL_USE )
+			/* Do nothing. */;
+		else {
+			EF_Abort(
+			 "free(%a): freeing free memory."
+			,address);
+		}
+	}
+
+	if ( EF_PROTECT_FREE )
+		slot->mode = PROTECTED;
+	else
+		slot->mode = FREE;
+
+       if ( EF_FREE_WIPES )
+               memset(slot->userAddress, 0xbd, slot->userSize);
+
+	previousSlot = slotForInternalAddressPreviousTo(slot->internalAddress);
+	nextSlot = slotForInternalAddress(
+	 ((char *)slot->internalAddress) + slot->internalSize);
+
+	if ( previousSlot
+	 && (previousSlot->mode == FREE || previousSlot->mode == PROTECTED) ) {
+		/* Coalesce previous slot with this one. */
+		previousSlot->internalSize += slot->internalSize;
+		if ( EF_PROTECT_FREE )
+			previousSlot->mode = PROTECTED;
+
+		slot->internalAddress = slot->userAddress = 0;
+		slot->internalSize = slot->userSize = 0;
+		slot->mode = NOT_IN_USE;
+		slot = previousSlot;
+		unUsedSlots++;
+	}
+	if ( nextSlot
+	 && (nextSlot->mode == FREE || nextSlot->mode == PROTECTED) ) {
+		/* Coalesce next slot with this one. */
+		slot->internalSize += nextSlot->internalSize;
+		nextSlot->internalAddress = nextSlot->userAddress = 0;
+		nextSlot->internalSize = nextSlot->userSize = 0;
+		nextSlot->mode = NOT_IN_USE;
+		unUsedSlots++;
+	}
+
+	slot->userAddress = slot->internalAddress;
+	slot->userSize = slot->internalSize;
+
+	/*
+	 * Free memory is _always_ set to deny access. When EF_PROTECT_FREE
+	 * is true, free memory is never reallocated, so it remains access
+	 * denied for the life of the process. When EF_PROTECT_FREE is false, 
+	 * the memory may be re-allocated, at which time access to it will be
+	 * allowed again.
+	 */
+	Page_DenyAccess(slot->internalAddress, slot->internalSize);
+
+	if ( !noAllocationListProtection )
+		Page_DenyAccess(allocationList, allocationListSize);
+
+        unlock();
+}
+
+extern C_LINKAGE void *
+ef_realloc(void * oldBuffer, size_t newSize)
+{
+	void *	newBuffer = ef_malloc(newSize);
+
+        lock();
+
+	if ( oldBuffer ) {
+		size_t	size;
+		Slot *	slot;
+
+		Page_AllowAccess(allocationList, allocationListSize);
+		noAllocationListProtection = 1;
+		
+		slot = slotForUserAddress(oldBuffer);
+
+		if ( slot == 0 )
+			EF_Abort(
+			 "realloc(%a, %d): address not from malloc()."
+			,oldBuffer
+			,newSize);
+
+		if ( newSize < (size = slot->userSize) )
+			size = newSize;
+
+		if ( size > 0 )
+			memcpy(newBuffer, oldBuffer, size);
+
+		ef_free(oldBuffer);
+		noAllocationListProtection = 0;
+		Page_DenyAccess(allocationList, allocationListSize);
+
+		if ( size < newSize )
+			memset(&(((char *)newBuffer)[size]), 0, newSize - size);
+		
+		/* Internal memory was re-protected in free() */
+	}
+	unlock();
+
+	return newBuffer;
+}
+
+extern C_LINKAGE void *
+ef_malloc(size_t size)
+{
+
+     if  ( malloc_init == 0 ){
+            ef_init();
+     }
+
+
+     void  *allocation;   
+
+    lock();
+    allocation=ef_memalign(EF_ALIGNMENT, size); 
+
+    /* put 0xaa into the memset to find uninit issues */
+    memset(allocation,0xaa,size);
+    #if 0
+    int i;
+    uint8_t *p=(uint8_t *)allocation;
+    for (i=0; i<size; i++) {
+        p[i]=(rand()&0xff);
+    }
+    #endif
+
+    unlock();
+    //printf(":: alloc %p %d \n",allocation,(int)size);
+	return allocation;
+}
+
+extern C_LINKAGE void *
+ef_calloc(size_t nelem, size_t elsize)
+{
+	size_t	size = nelem * elsize;
+        void * allocation;
+        
+        lock();
+       
+        allocation = ef_malloc(size);
+        memset(allocation, 0, size);
+        unlock();
+
+	return allocation;
+}
+
+/*
+ * This will catch more bugs if you remove the page alignment, but it
+ * will break some software.
+ */
+extern C_LINKAGE void *
+ef_valloc (size_t size)
+{
+        void * allocation;
+       
+        lock();
+        allocation= ef_memalign(bytesPerPage, size);
+        unlock();
+       
+        return allocation;
+}
+
+
+#define REPLACE_MALLOC
+
+#ifdef REPLACE_MALLOC
+
+extern C_LINKAGE void
+free(void * address)
+{
+    ef_free(address);
+}
+
+extern C_LINKAGE void *
+realloc(void * oldBuffer, size_t newSize)
+{
+    return (ef_realloc(oldBuffer, newSize));
+}
+
+extern C_LINKAGE void *
+malloc(size_t size)
+{
+    return (ef_malloc(size));
+}
+
+extern C_LINKAGE void *
+calloc(size_t nelem, size_t elsize)
+{
+    return (ef_calloc(nelem, elsize));
+}
+
+/*
+ * This will catch more bugs if you remove the page alignment, but it
+ * will break some software.
+ */
+extern C_LINKAGE void *
+valloc (size_t size)
+{
+    return (ef_valloc(size));
+
+}
+#endif
+
+
+
+extern C_LINKAGE void ef_init(void ){
+
+    if  ( malloc_init == 0 ){
+        malloc_init=1;
+        pthread_mutexattr_t Attr;
+
+        pthread_mutexattr_init(&Attr);
+        pthread_mutexattr_settype(&Attr, PTHREAD_MUTEX_RECURSIVE);
+
+        if ( pthread_mutex_init(&mutex, &Attr) != 0 ){
+            exit(-1);
+        }
+        initialize();   
+    }
+
+}
+