lib/libc/db/recno/rec_open.c

   1 /*      $NetBSD: rec_open.c,v 1.16 2008/09/10 17:52:36 joerg Exp $      */
   2
   3 /*-
   4  * Copyright (c) 1990, 1993, 1994
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Mike Olson.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #if HAVE_NBTOOL_CONFIG_H
  36 #include "nbtool_config.h"
  37 #endif
  38
  39 #include <sys/cdefs.h>
  40 __RCSID("$NetBSD: rec_open.c,v 1.16 2008/09/10 17:52:36 joerg Exp $");
  41
  42 #include "namespace.h"
  43 #include <sys/types.h>
  44 #include <sys/mman.h>
  45 #include <sys/stat.h>
  46
  47 #include <assert.h>
  48 #include <errno.h>
  49 #include <fcntl.h>
  50 #include <limits.h>
  51 #include <stddef.h>
  52 #include <stdio.h>
  53 #include <unistd.h>
  54
  55 #include <db.h>
  56 #include "recno.h"
  57
  58 DB *
  59 __rec_open(const char *fname, int flags, mode_t mode, const RECNOINFO *openinfo,
  60     int dflags)
  61 {
  62         BTREE *t;
  63         BTREEINFO btopeninfo;
  64         DB *dbp;
  65         PAGE *h;
  66         struct stat sb;
  67         int rfd = -1;   /* pacify gcc */
  68         int sverrno;
  69
  70         dbp = NULL;
  71         /* Open the user's file -- if this fails, we're done. */
  72         if (fname != NULL) {
  73                 if ((rfd = open(fname, flags, mode)) == -1)
  74                         return (NULL);
  75                 if (fcntl(rfd, F_SETFD, FD_CLOEXEC) == -1)
  76                         goto err;
  77         }
  78
  79         /* Create a btree in memory (backed by disk). */
  80         if (openinfo) {
  81                 if (openinfo->flags & ~(R_FIXEDLEN | R_NOKEY | R_SNAPSHOT))
  82                         goto einval;
  83                 btopeninfo.flags = 0;
  84                 btopeninfo.cachesize = openinfo->cachesize;
  85                 btopeninfo.maxkeypage = 0;
  86                 btopeninfo.minkeypage = 0;
  87                 btopeninfo.psize = openinfo->psize;
  88                 btopeninfo.compare = NULL;
  89                 btopeninfo.prefix = NULL;
  90                 btopeninfo.lorder = openinfo->lorder;
  91                 dbp = __bt_open(openinfo->bfname,
  92                     O_RDWR, S_IRUSR | S_IWUSR, &btopeninfo, dflags);
  93         } else
  94                 dbp = __bt_open(NULL, O_RDWR, S_IRUSR | S_IWUSR, NULL, dflags);
  95         if (dbp == NULL)
  96                 goto err;
  97
  98         /*
  99          * Some fields in the tree structure are recno specific.  Fill them
 100          * in and make the btree structure look like a recno structure.  We
 101          * don't change the bt_ovflsize value, it's close enough and slightly
 102          * bigger.
 103          */
 104         t = dbp->internal;
 105         if (openinfo) {
 106                 if (openinfo->flags & R_FIXEDLEN) {
 107                         F_SET(t, R_FIXLEN);
 108                         t->bt_reclen = openinfo->reclen;
 109                         if (t->bt_reclen == 0)
 110                                 goto einval;
 111                 }
 112                 t->bt_bval = openinfo->bval;
 113         } else
 114                 t->bt_bval = '\n';
 115
 116         F_SET(t, R_RECNO);
 117         if (fname == NULL)
 118                 F_SET(t, R_EOF | R_INMEM);
 119         else
 120                 t->bt_rfd = rfd;
 121
 122         if (fname != NULL) {
 123                 /*
 124                  * In 4.4BSD, stat(2) returns true for ISSOCK on pipes.
 125                  * Unfortunately, that's not portable, so we use lseek
 126                  * and check the errno values.
 127                  */
 128                 errno = 0;
 129                 if (lseek(rfd, (off_t)0, SEEK_CUR) == -1 && errno == ESPIPE) {
 130                         switch (flags & O_ACCMODE) {
 131                         case O_RDONLY:
 132                                 F_SET(t, R_RDONLY);
 133                                 break;
 134                         default:
 135                                 goto einval;
 136                         }
 137 slow:                   if ((t->bt_rfp = fdopen(rfd, "r")) == NULL)
 138                                 goto err;
 139                         F_SET(t, R_CLOSEFP);
 140                         t->bt_irec =
 141                             F_ISSET(t, R_FIXLEN) ? __rec_fpipe : __rec_vpipe;
 142                 } else {
 143                         switch (flags & O_ACCMODE) {
 144                         case O_RDONLY:
 145                                 F_SET(t, R_RDONLY);
 146                                 break;
 147                         case O_RDWR:
 148                                 break;
 149                         default:
 150                                 goto einval;
 151                         }
 152
 153                         if (fstat(rfd, &sb))
 154                                 goto err;
 155                         /*
 156                          * Kluge -- we'd like to test to see if the file is too
 157                          * big to mmap.  Since, we don't know what size or type
 158                          * off_t's or size_t's are, what the largest unsigned
 159                          * integral type is, or what random insanity the local
 160                          * C compiler will perpetrate, doing the comparison in
 161                          * a portable way is flatly impossible.  Hope that mmap
 162                          * fails if the file is too large.
 163                          */
 164                         if (sb.st_size == 0)
 165                                 F_SET(t, R_EOF);
 166                         else {
 167 #ifdef MMAP_NOT_AVAILABLE
 168                                 /*
 169                                  * XXX
 170                                  * Mmap doesn't work correctly on many current
 171                                  * systems.  In particular, it can fail subtly,
 172                                  * with cache coherency problems.  Don't use it
 173                                  * for now.
 174                                  */
 175                                 t->bt_msize = sb.st_size;
 176                                 if ((t->bt_smap = mmap(NULL, t->bt_msize,
 177                                     PROT_READ, MAP_FILE | MAP_PRIVATE, rfd,
 178                                     (off_t)0)) == (caddr_t)-1)
 179                                         goto slow;
 180                                 t->bt_cmap = t->bt_smap;
 181                                 t->bt_emap = t->bt_smap + sb.st_size;
 182                                 t->bt_irec = F_ISSET(t, R_FIXLEN) ?
 183                                     __rec_fmap : __rec_vmap;
 184                                 F_SET(t, R_MEMMAPPED);
 185 #else
 186                                 goto slow;
 187 #endif
 188                         }
 189                 }
 190         }
 191
 192         /* Use the recno routines. */
 193         dbp->close = __rec_close;
 194         dbp->del = __rec_delete;
 195         dbp->fd = __rec_fd;
 196         dbp->get = __rec_get;
 197         dbp->put = __rec_put;
 198         dbp->seq = __rec_seq;
 199         dbp->sync = __rec_sync;
 200
 201         /* If the root page was created, reset the flags. */
 202         if ((h = mpool_get(t->bt_mp, P_ROOT, 0)) == NULL)
 203                 goto err;
 204         if ((h->flags & P_TYPE) == P_BLEAF) {
 205                 F_CLR(h, P_TYPE);
 206                 F_SET(h, P_RLEAF);
 207                 mpool_put(t->bt_mp, h, MPOOL_DIRTY);
 208         } else
 209                 mpool_put(t->bt_mp, h, 0);
 210
 211         if (openinfo && openinfo->flags & R_SNAPSHOT &&
 212             !F_ISSET(t, R_EOF | R_INMEM) &&
 213             t->bt_irec(t, MAX_REC_NUMBER) == RET_ERROR)
 214                 goto err;
 215         return (dbp);
 216
 217 einval: errno = EINVAL;
 218 err:    sverrno = errno;
 219         if (dbp != NULL)
 220                 (void)__bt_close(dbp);
 221         if (fname != NULL)
 222                 (void)close(rfd);
 223         errno = sverrno;
 224         return (NULL);
 225 }
 226
 227 int
 228 __rec_fd(const DB *dbp)
 229 {
 230         BTREE *t;
 231
 232         t = dbp->internal;
 233
 234         /* Toss any page pinned across calls. */
 235         if (t->bt_pinned != NULL) {
 236                 mpool_put(t->bt_mp, t->bt_pinned, 0);
 237                 t->bt_pinned = NULL;
 238         }
 239
 240         /* In-memory database can't have a file descriptor. */
 241         if (F_ISSET(t, R_INMEM)) {
 242                 errno = ENOENT;
 243                 return (-1);
 244         }
 245         return (t->bt_rfd);
 246 }