db2/mp/mp_open.c

   1 /*-
   2  * See the file LICENSE for redistribution information.
   3  *
   4  * Copyright (c) 1996, 1997
   5  *      Sleepycat Software.  All rights reserved.
   6  */
   7 #include "config.h"
   8
   9 #ifndef lint
  10 static const char sccsid[] = "@(#)mp_open.c     10.15 (Sleepycat) 10/25/97";
  11 #endif /* not lint */
  12
  13 #ifndef NO_SYSTEM_INCLUDES
  14 #include <sys/types.h>
  15
  16 #include <errno.h>
  17 #include <fcntl.h>
  18 #include <stdlib.h>
  19 #include <string.h>
  20 #include <unistd.h>
  21 #endif
  22
  23 #include "db_int.h"
  24 #include "shqueue.h"
  25 #include "db_shash.h"
  26 #include "mp.h"
  27 #include "common_ext.h"
  28
  29 /*
  30  * memp_open --
  31  *      Initialize and/or join a memory pool.
  32  */
  33 int
  34 memp_open(path, flags, mode, dbenv, retp)
  35         const char *path;
  36         int flags, mode;
  37         DB_ENV *dbenv;
  38         DB_MPOOL **retp;
  39 {
  40         DB_MPOOL *dbmp;
  41         size_t cachesize;
  42         int ret;
  43
  44         /* Validate arguments. */
  45 #ifdef HAVE_SPINLOCKS
  46 #define OKFLAGS (DB_CREATE | DB_MPOOL_PRIVATE | DB_NOMMAP | DB_THREAD)
  47 #else
  48 #define OKFLAGS (DB_CREATE | DB_MPOOL_PRIVATE | DB_NOMMAP)
  49 #endif
  50         if ((ret = __db_fchk(dbenv, "memp_open", flags, OKFLAGS)) != 0)
  51                 return (ret);
  52
  53         /* Extract fields from DB_ENV structure. */
  54         cachesize = dbenv == NULL ? 0 : dbenv->mp_size;
  55
  56         /* Create and initialize the DB_MPOOL structure. */
  57         if ((dbmp = (DB_MPOOL *)__db_calloc(1, sizeof(DB_MPOOL))) == NULL)
  58                 return (ENOMEM);
  59         LIST_INIT(&dbmp->dbregq);
  60         TAILQ_INIT(&dbmp->dbmfq);
  61
  62         dbmp->dbenv = dbenv;
  63
  64         /* Decide if it's possible for anyone else to access the pool. */
  65         if ((dbenv == NULL && path == NULL) || LF_ISSET(DB_MPOOL_PRIVATE))
  66                 F_SET(dbmp, MP_ISPRIVATE);
  67
  68         /*
  69          * XXX
  70          * HP-UX won't permit mutexes to live in anything but shared memory.
  71          * So, we have to instantiate the shared mpool region file on that
  72          * architecture, regardless.  If this turns out to be a performance
  73          * problem, we could probably use anonymous memory instead.
  74          */
  75 #if defined(__hppa)
  76         F_CLR(dbmp, MP_ISPRIVATE);
  77 #endif
  78
  79         /*
  80          * Map in the region.  We do locking regardless, as portions of it are
  81          * implemented in common code (if we put the region in a file, that is).
  82          */
  83         F_SET(dbmp, MP_LOCKREGION);
  84         if ((ret = __memp_ropen(dbmp, path, cachesize, mode, flags)) != 0)
  85                 goto err;
  86         F_CLR(dbmp, MP_LOCKREGION);
  87
  88         /*
  89          * If there's concurrent access, then we have to lock the region.
  90          * If it's threaded, then we have to lock both the handles and the
  91          * region, and we need to allocate a mutex for that purpose.
  92          */
  93         if (!F_ISSET(dbmp, MP_ISPRIVATE))
  94                 F_SET(dbmp, MP_LOCKREGION);
  95         if (LF_ISSET(DB_THREAD)) {
  96                 F_SET(dbmp, MP_LOCKHANDLE | MP_LOCKREGION);
  97                 LOCKREGION(dbmp);
  98                 ret = __memp_ralloc(dbmp,
  99                     sizeof(db_mutex_t), NULL, &dbmp->mutexp);
 100                 UNLOCKREGION(dbmp);
 101                 if (ret != 0) {
 102                         (void)memp_close(dbmp);
 103                         goto err;
 104                 }
 105                 LOCKINIT(dbmp, dbmp->mutexp);
 106         }
 107
 108         *retp = dbmp;
 109         return (0);
 110
 111 err:    if (dbmp != NULL)
 112                 FREE(dbmp, sizeof(DB_MPOOL));
 113         return (ret);
 114 }
 115
 116 /*
 117  * memp_close --
 118  *      Close a memory pool.
 119  */
 120 int
 121 memp_close(dbmp)
 122         DB_MPOOL *dbmp;
 123 {
 124         DB_MPOOLFILE *dbmfp;
 125         DB_MPREG *mpreg;
 126         int ret, t_ret;
 127
 128         ret = 0;
 129
 130         /* Discard DB_MPREGs. */
 131         while ((mpreg = LIST_FIRST(&dbmp->dbregq)) != NULL) {
 132                 LIST_REMOVE(mpreg, q);
 133                 FREE(mpreg, sizeof(DB_MPREG));
 134         }
 135
 136         /* Discard DB_MPOOLFILEs. */
 137         while ((dbmfp = TAILQ_FIRST(&dbmp->dbmfq)) != NULL)
 138                 if ((t_ret = memp_fclose(dbmfp)) != 0 && ret == 0)
 139                         ret = t_ret;
 140
 141         /* Discard thread mutex. */
 142         if (F_ISSET(dbmp, MP_LOCKHANDLE)) {
 143                 LOCKREGION(dbmp);
 144                 __db_shalloc_free(dbmp->addr, dbmp->mutexp);
 145                 UNLOCKREGION(dbmp);
 146         }
 147
 148         /* Close the region. */
 149         if ((t_ret = __memp_rclose(dbmp)) && ret == 0)
 150                 ret = t_ret;
 151
 152         /* Discard the structure. */
 153         FREE(dbmp, sizeof(DB_MPOOL));
 154
 155         return (ret);
 156 }
 157
 158 /*
 159  * memp_unlink --
 160  *      Exit a memory pool.
 161  */
 162 int
 163 memp_unlink(path, force, dbenv)
 164         const char *path;
 165         int force;
 166         DB_ENV *dbenv;
 167 {
 168         return (__db_runlink(dbenv,
 169             DB_APP_NONE, path, DB_DEFAULT_MPOOL_FILE, force));
 170 }
 171
 172 /*
 173  * memp_register --
 174  *      Register a file type's pgin, pgout routines.
 175  */
 176 int
 177 memp_register(dbmp, ftype, pgin, pgout)
 178         DB_MPOOL *dbmp;
 179         int ftype;
 180         int (*pgin) __P((db_pgno_t, void *, DBT *));
 181         int (*pgout) __P((db_pgno_t, void *, DBT *));
 182 {
 183         DB_MPREG *mpr;
 184
 185         if ((mpr = (DB_MPREG *)__db_malloc(sizeof(DB_MPREG))) == NULL)
 186                 return (ENOMEM);
 187
 188         mpr->ftype = ftype;
 189         mpr->pgin = pgin;
 190         mpr->pgout = pgout;
 191
 192         /*
 193          * Insert at the head.  Because we do a linear walk, we'll find
 194          * the most recent registry in the case of multiple entries, so
 195          * we don't have to check for multiple registries.
 196          */
 197         LOCKHANDLE(dbmp, dbmp->mutexp);
 198         LIST_INSERT_HEAD(&dbmp->dbregq, mpr, q);
 199         UNLOCKHANDLE(dbmp, dbmp->mutexp);
 200
 201         return (0);
 202 }