shmem.h 3.01 KB
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/*-------------------------------------------------------------------------
 *
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 * shmem.h
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 *	  shared memory management structures
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 *
 *
 * Copyright (c) 1994, Regents of the University of California
 *
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 * $Id: shmem.h,v 1.21 1999/09/24 00:25:27 tgl Exp $
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 *
 *-------------------------------------------------------------------------
 */
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#ifndef SHMEM_H
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#define SHMEM_H

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#include "storage/spin.h"
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#include "utils/hsearch.h"
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/* The shared memory region can start at a different address
 * in every process.  Shared memory "pointers" are actually
 * offsets relative to the start of the shared memory region(s).
 */
typedef unsigned long SHMEM_OFFSET;
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#define INVALID_OFFSET (-1)
#define BAD_LOCATION (-1)

/* start of the lowest shared memory region.  For now, assume that
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 * there is only one shared memory region
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 */
extern SHMEM_OFFSET ShmemBase;


/* coerce an offset into a pointer in this process's address space */
#define MAKE_PTR(xx_offs)\
  (ShmemBase+((unsigned long)(xx_offs)))

/* coerce a pointer into a shmem offset */
#define MAKE_OFFSET(xx_ptr)\
  (SHMEM_OFFSET) (((unsigned long)(xx_ptr))-ShmemBase)

#define SHM_PTR_VALID(xx_ptr)\
  (((unsigned long)xx_ptr) > ShmemBase)

/* cannot have an offset to ShmemFreeStart (offset 0) */
#define SHM_OFFSET_VALID(xx_offs)\
  ((xx_offs != 0) && (xx_offs != INVALID_OFFSET))


extern SPINLOCK ShmemLock;
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extern SPINLOCK ShmemIndexLock;
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/* shmemqueue.c */
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typedef struct SHM_QUEUE
{
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	SHMEM_OFFSET prev;
	SHMEM_OFFSET next;
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} SHM_QUEUE;
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/* shmem.c */
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extern void ShmemIndexReset(void);
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extern void ShmemCreate(unsigned int key, unsigned int size);
extern int	InitShmem(unsigned int key, unsigned int size);
extern long *ShmemAlloc(unsigned long size);
extern int	ShmemIsValid(unsigned long addr);
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extern HTAB *ShmemInitHash(char *name, long init_size, long max_size,
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			  HASHCTL *infoP, int hash_flags);
extern bool ShmemPIDLookup(int pid, SHMEM_OFFSET *locationPtr);
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extern SHMEM_OFFSET ShmemPIDDestroy(int pid);
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extern long *ShmemInitStruct(char *name, unsigned long size,
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				bool *foundPtr);
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typedef int TableID;
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/* size constants for the shmem index table */
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 /* max size of data structure string name */
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#define SHMEM_INDEX_KEYSIZE (50)
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 /* data in shmem index table hash bucket */
#define SHMEM_INDEX_DATASIZE (sizeof(ShmemIndexEnt) - SHMEM_INDEX_KEYSIZE)
 /* maximum size of the shmem index table */
#define SHMEM_INDEX_SIZE		 (100)
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/* this is a hash bucket in the shmem index table */
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typedef struct
{
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	char		key[SHMEM_INDEX_KEYSIZE];		/* string name */
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	unsigned long location;		/* location in shared mem */
	unsigned long size;			/* numbytes allocated for the structure */
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} ShmemIndexEnt;
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/*
 * prototypes for functions in shmqueue.c
 */
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extern void SHMQueueInit(SHM_QUEUE *queue);
extern void SHMQueueElemInit(SHM_QUEUE *queue);
extern void SHMQueueDelete(SHM_QUEUE *queue);
extern void SHMQueueInsertTL(SHM_QUEUE *queue, SHM_QUEUE *elem);
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extern void SHMQueueFirst(SHM_QUEUE *queue, Pointer *nextPtrPtr,
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			  SHM_QUEUE *nextQueue);
extern bool SHMQueueEmpty(SHM_QUEUE *queue);
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#endif	 /* SHMEM_H */