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      this list of conditions and the following disclaimer.
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//=======================================================================
//									/
// FILE NAME								/
//    pool.c								/
//									/
// DESCRIPTION								/
//    This is the pool CS routines.					/
//									/
// DATA STRUCTURES							/
//    None								/
//									/
// FUNCTIONS								/
//    vs_pool_create		initialize the pool subsystem		/
//    vs_pool_delete		delete a pool subsystem			/
//    vs_pool_alloc		allocate a buffer			/
//    vs_pool_free		free a buffer				/
//									/
// DEPENDENCIES								/
//    ib_status.h							/
//    cs_g.h								/
//									/
//									/
// HISTORY								/
//									/
//    NAME	DATE  REMARKS						/
//     jsy  02/06/01  Initial creation of file.				/
//     jsy  03/14/01  Added additional checks. 				/
//     dkj  02/07/02  PR 468. Added vs_pool_page_size()                 /
//     dkj  04/01/02  PR 1676. Updated vs_pool_page_size to OS API 2.0g /
//=======================================================================

#include <stdlib.h>
#include <stdio.h>
#include <assert.h>
#include <string.h>
#include <signal.h>

// PAGE_SIZE and asm/page.h no longer supported on Linux
#ifndef PAGE_SIZE
#include <unistd.h>
#define PAGE_SIZE getpagesize()
#endif

#include "ib_status.h"
#include "cs_g.h"
#include "cs_log.h"

#ifdef LOCAL_MOD_ID
#undef LOCAL_MOD_ID
#endif
#define LOCAL_MOD_ID VIEO_CS_MOD_ID

#ifdef __GNUC__
#define function __FUNCTION__
#else
#define function "vs_implpool function"
#endif

/*
 * PBuffer_t linked list tricks Valgrind into thinking memory
 * is still reachable
 * */
#ifndef USE_PBUFFER_LIST
#define USE_PBUFFER_LIST 0
#endif

/*
 * buffer pool structure
*/
typedef	struct _PBuffer {
#if USE_PBUFFER_LIST
	struct		_PBuffer *next, *prev;
#endif /* USE_PBUFFER_LIST */
	uint8_t		*addr1;		// address of the user buffer
	uint16_t	sentinel;	// to track double delete
	uint32_t	size;
} PBuffer_t;

typedef struct
{
	uint64_t  numBytesAlloc;	// amount allocated from pool
#if USE_PBUFFER_LIST
	PBuffer_t *buffers;
#endif /* USE_PBUFFER_LIST */
} Implpriv_Pool_t;


/*
 * These defines control checks made during allocations and frees
 */

/* Add an extra eight bytes (sizeof uint64_t) to allocation size -
 * This was the way the original allocation code worked.
 */
#ifndef PAD_ALLOCATIONS
#define PAD_ALLOCATIONS 1
#endif

/* Aborts if an overwrite of the buffer is detected when it is freed */
#ifndef ABORT_ON_OVERWRITE
#define ABORT_ON_OVERWRITE 0
#endif

/* Aborts if a buffer is freed for a second time */
#ifndef ABORT_ON_DOUBLE_FREE
#define ABORT_ON_DOUBLE_FREE 1
#endif

/* Zeros out memory on both allocation and free */
#ifndef ZERO_FREED_MEM
#define ZERO_FREED_MEM 1
#endif

#if (ABORT_ON_OVERWRITE)
static const uint32_t sentinel0 = 0xB00A110C;
static const uint32_t sentinel1 = 0xE00A110C;
#endif

Status_t
vs_implpool_create(Pool_t *poolp, uint32_t options, uint8_t *name, void *address, uint32_t size) {

	IB_ENTER (function, poolp, options, address, size);

    /* Check to be sure that we have a valid Pool_t */

	if (poolp == NULL) {
		IB_EXIT (function, VSTATUS_ILLPARM);
		return(VSTATUS_ILLPARM);
	}

	/*
	   ** this is a run-time check to ensure that the opaque section of Pool_t
	   ** is large enough to contain the Implementation private data structure.
	   ** If this test fails, adjust the OPAQUE_POOL_ELEMENTS define in
	   ** vs_g.h and rebuild.
	 */
	if(sizeof (Implpriv_Pool_t) > sizeof (poolp->opaque))
	{
		IB_LOG_ERROR ("Implpriv_Pool_t too big:", sizeof (Implpriv_Pool_t));
		IB_EXIT (function, VSTATUS_ILLPARM);
		return VSTATUS_ILLPARM;
	}

    /* Initialize the pool */
	// caller has already zeroed *poolp
	strncpy((char*)poolp->name, (char *)name, VS_NAME_MAX);
	poolp->options = options;
#if USE_PBUFFER_LIST
	((Implpriv_Pool_t*)poolp->opaque)->buffers = NULL;
#endif /* USE_PBUFFER_LIST */

	IB_EXIT (function, VSTATUS_OK);
	return(VSTATUS_OK);
}


Status_t
vs_implpool_delete(Pool_t *poolp) {
	IB_ENTER (function, poolp, 0, 0, 0);

    /* Check to be sure that we have a valid Pool_t */
	if (poolp == NULL) {
		IB_EXIT (function, VSTATUS_ILLPARM);
		return(VSTATUS_ILLPARM);
	}

#if USE_PBUFFER_LIST
	PBuffer_t	*bufferp;
	Implpriv_Pool_t *impl = (Implpriv_Pool_t*) poolp->opaque;

    /* Delete all of the buffers remaining in the pool */
	while ((bufferp = impl->buffers) != NULL) {
		impl->buffers = bufferp->next;

#if (ZERO_FREED_MEM)
		memset(bufferp, 0, bufferp->size);
#endif

		free((void *)bufferp);
	}
#endif

	IB_EXIT (function, VSTATUS_OK);
	return(VSTATUS_OK);
}

#define AtomicAdd64(p,a) __sync_add_and_fetch((p),(a))
#define AtomicSubtract64(p,a) __sync_sub_and_fetch((p),(a))


Status_t
vs_implpool_alloc(Pool_t *poolp, uint32_t reqSize, void **address) {
	uint32_t		bytes;
	PBuffer_t	*bufferp;

	IB_ENTER (function, poolp, reqSize, address, 0);

    /* Check to be sure that we have a valid Pool_t */
	if (poolp == NULL) {
		IB_EXIT (function, VSTATUS_ILLPARM);
		return(VSTATUS_ILLPARM);
	}
// TBD - don't need Buffer_t header for normal case below, could save space

	DEBUG_ASSERT(reqSize < UINT32_MAX);

    /* See if we can get a buffer */
#if (PAD_ALLOCATIONS)
	/* This is the original calculation for number of bytes to allocate...
	 * Note the extra padding. This is sloppy. Also note that if both
	 * PAD_ALLOCATIONS and ABORT_ON_OVERWRITE are defined, that the sentinels
	 * are added to the the buffer _before_ the padding.
	 */
	DEBUG_ASSERT((UINT32_MAX - reqSize) >= (sizeof(PBuffer_t) + sizeof(uint64_t)));
	bytes = sizeof(PBuffer_t) + reqSize + sizeof(uint64_t);
#else
	DEBUG_ASSERT((UINT32_MAX - reqSize) >= sizeof(PBuffer_t));
	bytes = sizeof(PBuffer_t) + reqSize;
#endif

#if (ABORT_ON_OVERWRITE)
	bytes += (3 * sizeof(uint32_t));
#endif

	bufferp = (PBuffer_t *) malloc(bytes);
	if (bufferp == NULL) {
		IB_EXIT (function, VSTATUS_NOMEM);
		return(VSTATUS_NOMEM);
	}

// TBD vxworks doesn't do memset
	memset((void *)bufferp, 0, bytes);

	bufferp->sentinel = DELETE_MARKER;
	bufferp->addr1 = (uint8_t *)(bufferp+1);	// JSY - fix
	bufferp->size = bytes;

#if (ABORT_ON_OVERWRITE)
	/* We copy a constant value to the beginning of the buffer
	 * and a constant value to the end of the buffer, followed by the size
	 * of the buffer again. This allows us to make sure that we haven't
	 * overwritten the beginning or end of the allocated region when
	 * its freed.
	 *
	 * We memcpy here rather than cast and assign b/c these values may
	 * not necessarily be aligned, and that may cause problems on some
	 * architectures.
	 */
	memcpy(bufferp->addr1, &sentinel0, sizeof(uint32_t));

	/* adjust addr1 to account for the sentinel */
	bufferp->addr1 += sizeof(uint32_t);

	memcpy(bufferp->addr1 + reqSize, &sentinel1, sizeof(uint32_t));
	memcpy(bufferp->addr1 + reqSize + sizeof(uint32_t),
	       &bytes, sizeof(uint32_t));
#endif
	
#if USE_PBUFFER_LIST
	Implpriv_Pool_t *impl = (Implpriv_Pool_t*)poolp->opaque;
	bufferp->next = impl->buffers;
	bufferp->prev = NULL;
	if (impl->buffers != NULL)
		impl->buffers->prev = bufferp;
	impl->buffers = bufferp;
#endif /* USE_PBUFFER_LIST */
	*address = bufferp->addr1;

#if USE_POOL_LOCK
	((Implpriv_Pool_t *)poolp->opaque)->numBytesAlloc += bufferp->size;
#else
	uint64_t *ba = &((Implpriv_Pool_t*)poolp->opaque)->numBytesAlloc;
	AtomicAdd64(ba, bufferp->size);
#endif /* USE_POOL_LOCK */

	IB_EXIT (function, VSTATUS_OK);
	return(VSTATUS_OK);
}

static void freeBuffer(PBuffer_t * bufferp)
{
#if (ABORT_ON_OVERWRITE)
	uint32_t value = 0;
#endif

	IB_ENTER(function, bufferp, 0, 0, 0);

#if (ABORT_ON_OVERWRITE)
	/* Check whether we overwrote the beginning or the end of the
	 * allocated region
	 */
	memcpy(&value, bufferp->addr1 - sizeof(uint32_t), sizeof(uint32_t));
	assert(value == sentinel0);

#if (PAD_ALLOCATIONS)
	bufferp->size -= sizeof(uint64_t);
#endif /* PAD_ALLOCATIONS */

	memcpy(&value, ((uint8_t *) bufferp) + bufferp->size
	                  - (2 * sizeof(uint32_t)), sizeof(uint32_t));
	assert(value == sentinel1);

	memcpy(&value, ((uint8_t *) bufferp) + bufferp->size - sizeof(uint32_t),
	       sizeof(uint32_t));

#if (PAD_ALLOCATIONS)
	bufferp->size += sizeof(uint64_t);
#endif /* PAD_ALLOCATIONS */

	assert(value == bufferp->size);
#endif /* ABORT_ON_OVERWRITE */

#if (ZERO_FREED_MEM)
	memset(bufferp, 0, bufferp->size);
#endif
	free(bufferp);

	IB_EXIT(function, VSTATUS_OK);
}

Status_t
vs_implpool_free(Pool_t *poolp, void *address) {
	PBuffer_t	*bufferp;

	IB_ENTER (function, poolp, address, 0,0);

    /* Check to be sure that we have a valid Pool_t */
	if (poolp == NULL) {
		IB_EXIT (function, VSTATUS_ILLPARM);
		return(VSTATUS_ILLPARM);
	}

    /* Check to be sure that the address is a real one */
	if (address == NULL) {
		IB_EXIT (function, VSTATUS_ILLPARM);
		return(VSTATUS_ILLPARM);
	}

# if (ABORT_ON_OVERWRITE)
	address -= sizeof(uint32_t);
# endif

	// Pointer to the PBuffer_t should be at (address - sizeof(PBuffer_T))
	bufferp = (((PBuffer_t*) address) - 1);

	if (bufferp->sentinel != DELETE_MARKER) {
#if (ABORT_ON_DOUBLE_FREE)
    	/* Couldn't find the required buffer */
		IB_FATAL_ERROR("vs_implpool_free: could not find buffer to free");
#endif
		IB_EXIT (function, VSTATUS_ILLPARM);
		return(VSTATUS_ILLPARM);
	}
	
	bufferp->sentinel = 0;

#if USE_PBUFFER_LIST
	Implpriv_Pool_t *impl = (Implpriv_Pool_t*)poolp->opaque;
	if (bufferp->prev) {
		bufferp->prev->next = bufferp->next;
	} else {
		impl->buffers = bufferp->next; // at head of list
	} 
	if (bufferp->next) {
		bufferp->next->prev = bufferp->prev;
	}
#endif /* USE_PBUFFER_LIST */

#if USE_POOL_LOCK
	((Implpriv_Pool_t *)poolp->opaque)->numBytesAlloc -= bufferp->size;
#else
	uint64_t *ba = &((Implpriv_Pool_t*)poolp->opaque)->numBytesAlloc;
	AtomicSubtract64(ba, bufferp->size);
#endif

	freeBuffer(bufferp);
	IB_EXIT (function, VSTATUS_OK);
	return VSTATUS_OK;
}

/**********************************************************************
*
* FUNCTION
*    vs_implpool_size
*
* OUTPUTS
*      number of bytes allocated from pool.
**********************************************************************/
Status_t
vs_implpool_size(Pool_t *poolp, uint64_t *numBytesAlloc)
{
	// caller already validated poolp and size
	*numBytesAlloc = ((Implpriv_Pool_t *)poolp->opaque)->numBytesAlloc;
	return VSTATUS_OK;
}

size_t vs_pool_page_size (void) {
  IB_ENTER (function, (uint32_t) 0U, (uint32_t) 0U, (uint32_t) 0U, (uint32_t) 0U);
  IB_EXIT (function, (size_t) PAGE_SIZE);
  return (size_t) PAGE_SIZE;
}