drvrsmem.h

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/*              S H A R E D   M E M O R Y   D R I V E R
                =======================================

                  by Jerzy.Borkowski@obs.unige.ch

09-Mar-98 : initial version 1.0 released
23-Mar-98 : shared_malloc now accepts new handle as an argument
*/


#include <sys/ipc.h>            /* this is necessary for Solaris/Linux */
#include <sys/shm.h>
#include <sys/sem.h>

#ifdef _AIX
#include <fcntl.h>
#else
#include <sys/fcntl.h>
#endif

                /* configuration parameters */

#define SHARED_MAXSEG   (16)            /* maximum number of shared memory blocks */

#define SHARED_KEYBASE  (14011963)      /* base for shared memory keys, may be overriden by getenv */
#define SHARED_FDNAME   ("/tmp/.shmem-lockfile") /* template for lock file name */

#define SHARED_ENV_KEYBASE ("SHMEM_LIB_KEYBASE") /* name of environment variable */
#define SHARED_ENV_MAXSEG ("SHMEM_LIB_MAXSEG")  /* name of environment variable */

                /* useful constants */

#define SHARED_RDONLY   (0)             /* flag for shared_(un)lock, lock for read */
#define SHARED_RDWRITE  (1)             /* flag for shared_(un)lock, lock for write */
#define SHARED_WAIT     (0)             /* flag for shared_lock, block if cannot lock immediate */
#define SHARED_NOWAIT   (2)             /* flag for shared_lock, fail if cannot lock immediate */
#define SHARED_NOLOCK   (0x100)         /* flag for shared_validate function */

#define SHARED_RESIZE   (4)             /* flag for shared_malloc, object is resizeable */
#define SHARED_PERSIST  (8)             /* flag for shared_malloc, object is not deleted after last proc detaches */

#define SHARED_INVALID  (-1)            /* invalid handle for semaphore/shared memory */

#define SHARED_EMPTY    (0)             /* entries for shared_used table */
#define SHARED_USED     (1)

#define SHARED_GRANUL   (16384)         /* granularity of shared_malloc allocation = phys page size, system dependent */



                /* checkpoints in shared memory segments - might be omitted */

#define SHARED_ID_0     ('J')           /* first byte of identifier in BLKHEAD */
#define SHARED_ID_1     ('B')           /* second byte of identifier in BLKHEAD */

#define BLOCK_REG       (0)             /* value for tflag member of BLKHEAD */
#define BLOCK_SHARED    (1)             /* value for tflag member of BLKHEAD */

                /* generic error codes */

#define SHARED_OK       (0)

#define SHARED_ERR_MIN_IDX      SHARED_BADARG
#define SHARED_ERR_MAX_IDX      SHARED_NORESIZE


#define DAL_SHM_FREE    (0)
#define DAL_SHM_USED    (1)

#define DAL_SHM_ID0     ('D')
#define DAL_SHM_ID1     ('S')
#define DAL_SHM_ID2     ('M')

#define DAL_SHM_SEGHEAD_ID      (0x19630114)



                /* data types */

/* BLKHEAD object is placed at the beginning of every memory segment (both
  shared and regular) to allow automatic recognition of segments type */

typedef union
      { struct BLKHEADstruct
              { char    ID[2];          /* ID = 'JB', just as a checkpoint */
                char    tflag;          /* is it shared memory or regular one ? */
                int     handle;         /* this is not necessary, used only for non-resizeable objects via ptr */
              } s;
        double  d;                      /* for proper alignment on every machine */
      } BLKHEAD;

typedef void *SHARED_P;                 /* generic type of shared memory pointer */

typedef struct SHARED_GTABstruct        /* data type used in global table */
      { int     sem;                    /* access semaphore (1 field): process count */
        int     semkey;                 /* key value used to generate semaphore handle */
        int     key;                    /* key value used to generate shared memory handle (realloc changes it) */
        int     handle;                 /* handle of shared memory segment */
        int     size;                   /* size of shared memory segment */
        int     nprocdebug;             /* attached proc counter, helps remove zombie segments */
        char    attr;                   /* attributes of shared memory object */
      } SHARED_GTAB;

typedef struct SHARED_LTABstruct        /* data type used in local table */
      { BLKHEAD *p;                     /* pointer to segment (may be null) */
        int     tcnt;                   /* number of threads in this process attached to segment */
        int     lkcnt;                  /* >=0 <- number of read locks, -1 - write lock */
        long    seekpos;                /* current pointer position, read/write/seek operations change it */
      } SHARED_LTAB;


        /* system dependent definitions */

#ifndef HAVE_FLOCK_T
typedef struct flock flock_t;
#define HAVE_FLOCK_T
#endif

#ifndef HAVE_UNION_SEMUN
union semun
      { int val;
        struct semid_ds *buf;
        unsigned short *array;
      };
#define HAVE_UNION_SEMUN
#endif


typedef struct DAL_SHM_SEGHEAD_STRUCT   DAL_SHM_SEGHEAD;

struct DAL_SHM_SEGHEAD_STRUCT
      { int     ID;                     /* ID for debugging */
        int     h;                      /* handle of sh. mem */
        int     size;                   /* size of data area */
        int     nodeidx;                /* offset of root object (node struct typically) */
      };

                /* API routines */

#ifdef __cplusplus
extern "C" {
#endif

void    shared_cleanup(void);                   /* must be called at exit/abort */
int     shared_init(int debug_msgs);            /* must be called before any other shared memory routine */
int     shared_recover(int id);                 /* try to recover dormant segment(s) after applic crash */
int     shared_malloc(long size, int mode, int newhandle);      /* allocate n-bytes of shared memory */
int     shared_attach(int idx);                 /* attach to segment given index to table */
int     shared_free(int idx);                   /* release shared memory */
SHARED_P shared_lock(int idx, int mode);        /* lock segment for reading */
SHARED_P shared_realloc(int idx, long newsize); /* reallocate n-bytes of shared memory (ON LOCKED SEGMENT ONLY) */
int     shared_size(int idx);                   /* get size of attached shared memory segment (ON LOCKED SEGMENT ONLY) */
int     shared_attr(int idx);                   /* get attributes of attached shared memory segment (ON LOCKED SEGMENT ONLY) */
int     shared_set_attr(int idx, int newattr);  /* set attributes of attached shared memory segment (ON LOCKED SEGMENT ONLY) */
int     shared_unlock(int idx);                 /* unlock segment (ON LOCKED SEGMENT ONLY) */
int     shared_set_debug(int debug_msgs);       /* set/reset debug mode */
int     shared_set_createmode(int mode);        /* set/reset debug mode */
int     shared_list(int id);                    /* list segment(s) */
int     shared_uncond_delete(int id);           /* uncondintionally delete (NOWAIT operation) segment(s) */
int     shared_getaddr(int id, char **address); /* get starting address of FITS file in segment */

int     smem_init(void);
int     smem_shutdown(void);
int     smem_setoptions(int options);
int     smem_getoptions(int *options);
int     smem_getversion(int *version);
int     smem_open(char *filename, int rwmode, int *driverhandle);
int     smem_create(char *filename, int *driverhandle);
int     smem_close(int driverhandle);
int     smem_remove(char *filename);
int     smem_size(int driverhandle, LONGLONG *size);
int     smem_flush(int driverhandle);
int     smem_seek(int driverhandle, LONGLONG offset);
int     smem_read(int driverhandle, void *buffer, long nbytes);
int     smem_write(int driverhandle, void *buffer, long nbytes);

#ifdef __cplusplus
}
#endif