git.sur5r.net Git - openldap/blob - servers/slapd/back-ldbm/dbcache.c

   1 /* ldbmcache.c - maintain a cache of open ldbm files */
   2 /* $OpenLDAP$ */
   3 /*
   4  * Copyright 1998-2000 The OpenLDAP Foundation, All Rights Reserved.
   5  * COPYING RESTRICTIONS APPLY, see COPYRIGHT file
   6  */
   7
   8 #include "portable.h"
   9
  10 #include <stdio.h>
  11
  12 #include <ac/errno.h>
  13 #include <ac/socket.h>
  14 #include <ac/string.h>
  15 #include <ac/time.h>
  16 #include <sys/stat.h>
  17
  18 #include "slap.h"
  19 #include "back-ldbm.h"
  20
  21 DBCache *
  22 ldbm_cache_open(
  23     Backend     *be,
  24     const char  *name,
  25     const char  *suffix,
  26     int         flags
  27 )
  28 {
  29         struct ldbminfo *li = (struct ldbminfo *) be->be_private;
  30         int             i, lru, empty;
  31         time_t          oldtime, curtime;
  32         char            buf[MAXPATHLEN];
  33 #ifdef HAVE_ST_BLKSIZE
  34         struct stat     st;
  35 #endif
  36
  37         sprintf( buf, "%s" LDAP_DIRSEP "%s%s",
  38                 li->li_directory, name, suffix );
  39
  40         if( li->li_dblocking ) {
  41                 flags |= LDBM_LOCKING;
  42         } else {
  43                 flags |= LDBM_NOLOCKING;
  44         }
  45
  46         if( li->li_dbwritesync ) {
  47                 flags |= LDBM_SYNC;
  48         } else {
  49                 flags |= LDBM_NOSYNC;
  50         }
  51
  52         Debug( LDAP_DEBUG_TRACE, "=> ldbm_cache_open( \"%s\", %d, %o )\n", buf,
  53             flags, li->li_mode );
  54
  55         curtime = slap_get_time();
  56         empty = MAXDBCACHE;
  57
  58         ldap_pvt_thread_mutex_lock( &li->li_dbcache_mutex );
  59         do {
  60                 lru = 0;
  61                 oldtime = curtime;
  62                 for ( i = 0; i < MAXDBCACHE; i++ ) {
  63                         /* see if this slot is free */
  64                         if ( li->li_dbcache[i].dbc_name == NULL) {
  65                                 empty = i;
  66                                 continue;
  67                         }
  68
  69                         if ( strcmp( li->li_dbcache[i].dbc_name, buf ) == 0 ) {
  70                                 /* already open - return it */
  71                                 if (li->li_dbcache[i].dbc_flags != flags
  72                                         && li->li_dbcache[i].dbc_refcnt == 0)
  73                                 {
  74                                         /* we don't want to use an open cache with different
  75                                          * permissions (esp. if we need write but the open
  76                                          * cache is read-only).  So close this one if
  77                                          * possible, and re-open below.
  78                                          *
  79                                          * FIXME:  what about the case where the refcount
  80                                          * is > 0?  right now, we're using it anyway and
  81                                          * just praying.  Can there be more than one open
  82                                          * cache to the same db?
  83                                          *
  84                                          * Also, it's really only necessary to compare the
  85                                          * read-only flag, instead of all of the flags,
  86                                          * but for now I'm checking all of them.
  87                                          */
  88                                         lru = i;
  89                                         empty = MAXDBCACHE;
  90                                         break;
  91                                 }
  92                                 li->li_dbcache[i].dbc_refcnt++;
  93                                 Debug( LDAP_DEBUG_TRACE,
  94                                     "<= ldbm_cache_open (cache %d)\n", i, 0, 0 );
  95                                 ldap_pvt_thread_mutex_unlock( &li->li_dbcache_mutex );
  96                                 return( &li->li_dbcache[i] );
  97                         }
  98
  99                         /* keep track of lru db */
 100                         if ( li->li_dbcache[i].dbc_lastref < oldtime
 101                                 && li->li_dbcache[i].dbc_refcnt == 0 )
 102                         {
 103                                 lru = i;
 104                                 oldtime = li->li_dbcache[i].dbc_lastref;
 105                         }
 106                 }
 107
 108                 i = empty;
 109                 if ( i == MAXDBCACHE ) {
 110                         /* no empty slots, not already open - close lru and use that slot */
 111                         if ( li->li_dbcache[lru].dbc_refcnt == 0 ) {
 112                                 i = lru;
 113                                 ldbm_close( li->li_dbcache[i].dbc_db );
 114                                 free( li->li_dbcache[i].dbc_name );
 115                                 li->li_dbcache[i].dbc_name = NULL;
 116                         } else {
 117                                 Debug( LDAP_DEBUG_ANY,
 118                                     "ldbm_cache_open no unused db to close - waiting\n",
 119                                     0, 0, 0 );
 120                                 ldap_pvt_thread_cond_wait( &li->li_dbcache_cv,
 121                                             &li->li_dbcache_mutex );
 122                                 /* after waiting for a free slot, go back to square
 123                                  * one: look for an open cache for this db, or an
 124                                  * empty slot, or an unref'ed cache, or wait again.
 125                                  */
 126                         }
 127                 }
 128         } while (i == MAXDBCACHE);
 129
 130         if ( (li->li_dbcache[i].dbc_db = ldbm_open( buf, flags, li->li_mode,
 131             li->li_dbcachesize )) == NULL )
 132         {
 133                 int err = errno;
 134                 Debug( LDAP_DEBUG_TRACE,
 135                     "<= ldbm_cache_open NULL \"%s\" errno=%d reason=\"%s\")\n",
 136                     buf, err, err > -1 && err < sys_nerr ?
 137                     sys_errlist[err] : "unknown" );
 138                 ldap_pvt_thread_mutex_unlock( &li->li_dbcache_mutex );
 139                 return( NULL );
 140         }
 141         li->li_dbcache[i].dbc_name = ch_strdup( buf );
 142         li->li_dbcache[i].dbc_refcnt = 1;
 143         li->li_dbcache[i].dbc_lastref = curtime;
 144         li->li_dbcache[i].dbc_flags = flags;
 145         li->li_dbcache[i].dbc_dirty = 0;
 146 #ifdef HAVE_ST_BLKSIZE
 147         if ( stat( buf, &st ) == 0 ) {
 148                 li->li_dbcache[i].dbc_blksize = st.st_blksize;
 149         } else
 150 #endif
 151         {
 152                 li->li_dbcache[i].dbc_blksize = DEFAULT_BLOCKSIZE;
 153         }
 154         li->li_dbcache[i].dbc_maxids = (li->li_dbcache[i].dbc_blksize /
 155             sizeof(ID)) - ID_BLOCK_IDS_OFFSET;
 156         li->li_dbcache[i].dbc_maxindirect = ( SLAPD_LDBM_MIN_MAXIDS /
 157             li->li_dbcache[i].dbc_maxids ) + 1;
 158
 159         assert( li->li_dbcache[i].dbc_maxindirect < 256 );
 160
 161         Debug( LDAP_DEBUG_ARGS,
 162             "ldbm_cache_open (blksize %ld) (maxids %d) (maxindirect %d)\n",
 163             li->li_dbcache[i].dbc_blksize, li->li_dbcache[i].dbc_maxids,
 164             li->li_dbcache[i].dbc_maxindirect );
 165         Debug( LDAP_DEBUG_TRACE, "<= ldbm_cache_open (opened %d)\n", i, 0, 0 );
 166         ldap_pvt_thread_mutex_unlock( &li->li_dbcache_mutex );
 167         return( &li->li_dbcache[i] );
 168 }
 169
 170 void
 171 ldbm_cache_close( Backend *be, DBCache *db )
 172 {
 173         struct ldbminfo *li = (struct ldbminfo *) be->be_private;
 174
 175         if( li->li_dbwritesync && db->dbc_dirty ) {
 176                 ldbm_sync( db->dbc_db );
 177                 db->dbc_dirty = 0;
 178         }
 179
 180         ldap_pvt_thread_mutex_lock( &li->li_dbcache_mutex );
 181         if ( --db->dbc_refcnt <= 0 ) {
 182                 db->dbc_refcnt = 0;
 183                 ldap_pvt_thread_cond_signal( &li->li_dbcache_cv );
 184         }
 185         ldap_pvt_thread_mutex_unlock( &li->li_dbcache_mutex );
 186 }
 187
 188 void
 189 ldbm_cache_really_close( Backend *be, DBCache *db )
 190 {
 191         struct ldbminfo *li = (struct ldbminfo *) be->be_private;
 192
 193         ldap_pvt_thread_mutex_lock( &li->li_dbcache_mutex );
 194         if ( --db->dbc_refcnt <= 0 ) {
 195                 db->dbc_refcnt = 0;
 196                 ldap_pvt_thread_cond_signal( &li->li_dbcache_cv );
 197                 ldbm_close( db->dbc_db );
 198                 free( db->dbc_name );
 199                 db->dbc_name = NULL;
 200         }
 201         ldap_pvt_thread_mutex_unlock( &li->li_dbcache_mutex );
 202 }
 203
 204 void
 205 ldbm_cache_flush_all( Backend *be )
 206 {
 207         struct ldbminfo *li = (struct ldbminfo *) be->be_private;
 208         int             i;
 209
 210         ldap_pvt_thread_mutex_lock( &li->li_dbcache_mutex );
 211         for ( i = 0; i < MAXDBCACHE; i++ ) {
 212                 if ( li->li_dbcache[i].dbc_name != NULL ) {
 213                         Debug( LDAP_DEBUG_TRACE, "ldbm flushing db (%s)\n",
 214                             li->li_dbcache[i].dbc_name, 0, 0 );
 215                         ldbm_sync( li->li_dbcache[i].dbc_db );
 216                         li->li_dbcache[i].dbc_dirty = 0;
 217                         if ( li->li_dbcache[i].dbc_refcnt != 0 ) {
 218                                 Debug( LDAP_DEBUG_TRACE,
 219                                        "refcnt = %d, couldn't close db (%s)\n",
 220                                        li->li_dbcache[i].dbc_refcnt,
 221                                        li->li_dbcache[i].dbc_name, 0 );
 222                         } else {
 223                                 Debug( LDAP_DEBUG_TRACE,
 224                                        "ldbm closing db (%s)\n",
 225                                        li->li_dbcache[i].dbc_name, 0, 0 );
 226                                 ldap_pvt_thread_cond_signal( &li->li_dbcache_cv );
 227                                 ldbm_close( li->li_dbcache[i].dbc_db );
 228                                 free( li->li_dbcache[i].dbc_name );
 229                                 li->li_dbcache[i].dbc_name = NULL;
 230                         }
 231                 }
 232         }
 233         ldap_pvt_thread_mutex_unlock( &li->li_dbcache_mutex );
 234 }
 235
 236 Datum
 237 ldbm_cache_fetch(
 238     DBCache     *db,
 239     Datum               key
 240 )
 241 {
 242         Datum   data;
 243
 244         return ldbm_fetch( db->dbc_db, key );
 245
 246         return( data );
 247 }
 248
 249 int
 250 ldbm_cache_store(
 251     DBCache     *db,
 252     Datum               key,
 253     Datum               data,
 254     int                 flags
 255 )
 256 {
 257         int     rc;
 258
 259 #ifdef LDBM_DEBUG
 260         Statslog( LDAP_DEBUG_STATS,
 261                 "=> ldbm_cache_store(): key.dptr=%s, key.dsize=%d\n",
 262                 key.dptr, key.dsize, 0, 0, 0 );
 263
 264         Statslog( LDAP_DEBUG_STATS,
 265                 "=> ldbm_cache_store(): key.dptr=0x%08x, data.dptr=0x%0 8x\n",
 266                 key.dptr, data.dptr, 0, 0, 0 );
 267
 268         Statslog( LDAP_DEBUG_STATS,
 269                 "=> ldbm_cache_store(): data.dptr=%s, data.dsize=%d\n",
 270                 data.dptr, data.dsize, 0, 0, 0 );
 271
 272         Statslog( LDAP_DEBUG_STATS,
 273                 "=> ldbm_cache_store(): flags=0x%08x\n",
 274                 flags, 0, 0, 0, 0 );
 275 #endif /* LDBM_DEBUG */
 276
 277         db->dbc_dirty = 1;
 278         rc = ldbm_store( db->dbc_db, key, data, flags );
 279
 280         return( rc );
 281 }
 282
 283 int
 284 ldbm_cache_delete(
 285     DBCache     *db,
 286     Datum               key
 287 )
 288 {
 289         int     rc;
 290
 291         db->dbc_dirty = 1;
 292         rc = ldbm_delete( db->dbc_db, key );
 293
 294         return( rc );
 295 }