db.1.85/recno/rec_open.c

   1 /*-
   2  * Copyright (c) 1990, 1993, 1994
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Mike Olson.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  */
  36
  37 #if defined(LIBC_SCCS) && !defined(lint)
  38 static char sccsid[] = "@(#)rec_open.c  8.10 (Berkeley) 9/1/94";
  39 #endif /* LIBC_SCCS and not lint */
  40
  41 #include <sys/types.h>
  42 #include <sys/mman.h>
  43 #include <sys/stat.h>
  44
  45 #include <errno.h>
  46 #include <fcntl.h>
  47 #include <limits.h>
  48 #include <stddef.h>
  49 #include <stdio.h>
  50 #include <unistd.h>
  51
  52 #include <db.h>
  53 #include "recno.h"
  54
  55 DB *
  56 __rec_open(fname, flags, mode, openinfo, dflags)
  57         const char *fname;
  58         int flags, mode, dflags;
  59         const RECNOINFO *openinfo;
  60 {
  61         BTREE *t;
  62         BTREEINFO btopeninfo;
  63         DB *dbp;
  64         PAGE *h;
  65         struct stat sb;
  66         int rfd, sverrno;
  67
  68         /* Open the user's file -- if this fails, we're done. */
  69         if (fname != NULL && (rfd = open(fname, flags, mode)) < 0)
  70                 return (NULL);
  71
  72         /* Create a btree in memory (backed by disk). */
  73         dbp = NULL;
  74         if (openinfo) {
  75                 if (openinfo->flags & ~(R_FIXEDLEN | R_NOKEY | R_SNAPSHOT))
  76                         goto einval;
  77                 btopeninfo.flags = 0;
  78                 btopeninfo.cachesize = openinfo->cachesize;
  79                 btopeninfo.maxkeypage = 0;
  80                 btopeninfo.minkeypage = 0;
  81                 btopeninfo.psize = openinfo->psize;
  82                 btopeninfo.compare = NULL;
  83                 btopeninfo.prefix = NULL;
  84                 btopeninfo.lorder = openinfo->lorder;
  85                 dbp = __bt_open(openinfo->bfname,
  86                     O_RDWR, S_IRUSR | S_IWUSR, &btopeninfo, dflags);
  87         } else
  88                 dbp = __bt_open(NULL, O_RDWR, S_IRUSR | S_IWUSR, NULL, dflags);
  89         if (dbp == NULL)
  90                 goto err;
  91
  92         /*
  93          * Some fields in the tree structure are recno specific.  Fill them
  94          * in and make the btree structure look like a recno structure.  We
  95          * don't change the bt_ovflsize value, it's close enough and slightly
  96          * bigger.
  97          */
  98         t = dbp->internal;
  99         if (openinfo) {
 100                 if (openinfo->flags & R_FIXEDLEN) {
 101                         F_SET(t, R_FIXLEN);
 102                         t->bt_reclen = openinfo->reclen;
 103                         if (t->bt_reclen == 0)
 104                                 goto einval;
 105                 }
 106                 t->bt_bval = openinfo->bval;
 107         } else
 108                 t->bt_bval = '\n';
 109
 110         F_SET(t, R_RECNO);
 111         if (fname == NULL)
 112                 F_SET(t, R_EOF | R_INMEM);
 113         else
 114                 t->bt_rfd = rfd;
 115
 116         if (fname != NULL) {
 117                 /*
 118                  * In 4.4BSD, stat(2) returns true for ISSOCK on pipes.
 119                  * Unfortunately, that's not portable, so we use lseek
 120                  * and check the errno values.
 121                  */
 122                 errno = 0;
 123                 if (lseek(rfd, (off_t)0, SEEK_CUR) == -1 && errno == ESPIPE) {
 124                         switch (flags & O_ACCMODE) {
 125                         case O_RDONLY:
 126                                 F_SET(t, R_RDONLY);
 127                                 break;
 128                         default:
 129                                 goto einval;
 130                         }
 131 slow:                   if ((t->bt_rfp = fdopen(rfd, "r")) == NULL)
 132                                 goto err;
 133                         F_SET(t, R_CLOSEFP);
 134                         t->bt_irec =
 135                             F_ISSET(t, R_FIXLEN) ? __rec_fpipe : __rec_vpipe;
 136                 } else {
 137                         switch (flags & O_ACCMODE) {
 138                         case O_RDONLY:
 139                                 F_SET(t, R_RDONLY);
 140                                 break;
 141                         case O_RDWR:
 142                                 break;
 143                         default:
 144                                 goto einval;
 145                         }
 146
 147                         if (fstat(rfd, &sb))
 148                                 goto err;
 149                         /*
 150                          * Kluge -- we'd like to test to see if the file is too
 151                          * big to mmap.  Since, we don't know what size or type
 152                          * off_t's or size_t's are, what the largest unsigned
 153                          * integral type is, or what random insanity the local
 154                          * C compiler will perpetrate, doing the comparison in
 155                          * a portable way is flatly impossible.  Hope that mmap
 156                          * fails if the file is too large.
 157                          */
 158                         if (sb.st_size == 0)
 159                                 F_SET(t, R_EOF);
 160                         else {
 161 #ifdef MMAP_NOT_AVAILABLE
 162                                 /*
 163                                  * XXX
 164                                  * Mmap doesn't work correctly on many current
 165                                  * systems.  In particular, it can fail subtly,
 166                                  * with cache coherency problems.  Don't use it
 167                                  * for now.
 168                                  */
 169                                 t->bt_msize = sb.st_size;
 170                                 if ((t->bt_smap = mmap(NULL, t->bt_msize,
 171                                     PROT_READ, MAP_PRIVATE, rfd,
 172                                     (off_t)0)) == (caddr_t)-1)
 173                                         goto slow;
 174                                 t->bt_cmap = t->bt_smap;
 175                                 t->bt_emap = t->bt_smap + sb.st_size;
 176                                 t->bt_irec = F_ISSET(t, R_FIXLEN) ?
 177                                     __rec_fmap : __rec_vmap;
 178                                 F_SET(t, R_MEMMAPPED);
 179 #else
 180                                 goto slow;
 181 #endif
 182                         }
 183                 }
 184         }
 185
 186         /* Use the recno routines. */
 187         dbp->close = __rec_close;
 188         dbp->del = __rec_delete;
 189         dbp->fd = __rec_fd;
 190         dbp->get = __rec_get;
 191         dbp->put = __rec_put;
 192         dbp->seq = __rec_seq;
 193         dbp->sync = __rec_sync;
 194
 195         /* If the root page was created, reset the flags. */
 196         if ((h = mpool_get(t->bt_mp, P_ROOT, 0)) == NULL)
 197                 goto err;
 198         if ((h->flags & P_TYPE) == P_BLEAF) {
 199                 F_CLR(h, P_TYPE);
 200                 F_SET(h, P_RLEAF);
 201                 mpool_put(t->bt_mp, h, MPOOL_DIRTY);
 202         } else
 203                 mpool_put(t->bt_mp, h, 0);
 204
 205         if (openinfo && openinfo->flags & R_SNAPSHOT &&
 206             !F_ISSET(t, R_EOF | R_INMEM) &&
 207             t->bt_irec(t, MAX_REC_NUMBER) == RET_ERROR)
 208                 goto err;
 209         return (dbp);
 210
 211 einval: errno = EINVAL;
 212 err:    sverrno = errno;
 213         if (dbp != NULL)
 214                 (void)__bt_close(dbp);
 215         if (fname != NULL)
 216                 (void)close(rfd);
 217         errno = sverrno;
 218         return (NULL);
 219 }
 220
 221 int
 222 __rec_fd(dbp)
 223         const DB *dbp;
 224 {
 225         BTREE *t;
 226
 227         t = dbp->internal;
 228
 229         /* Toss any page pinned across calls. */
 230         if (t->bt_pinned != NULL) {
 231                 mpool_put(t->bt_mp, t->bt_pinned, 0);
 232                 t->bt_pinned = NULL;
 233         }
 234
 235         /* In-memory database can't have a file descriptor. */
 236         if (F_ISSET(t, R_INMEM)) {
 237                 errno = ENOENT;
 238                 return (-1);
 239         }
 240         return (t->bt_rfd);
 241 }