db.subproj/recno.subproj/rec_open.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) 1990, 1993
  24  *      The Regents of the University of California.  All rights reserved.
  25  *
  26  * This code is derived from software contributed to Berkeley by
  27  * Mike Olson.
  28  *
  29  * Redistribution and use in source and binary forms, with or without
  30  * modification, are permitted provided that the following conditions
  31  * are met:
  32  * 1. Redistributions of source code must retain the above copyright
  33  *    notice, this list of conditions and the following disclaimer.
  34  * 2. Redistributions in binary form must reproduce the above copyright
  35  *    notice, this list of conditions and the following disclaimer in the
  36  *    documentation and/or other materials provided with the distribution.
  37  * 3. All advertising materials mentioning features or use of this software
  38  *    must display the following acknowledgement:
  39  *      This product includes software developed by the University of
  40  *      California, Berkeley and its contributors.
  41  * 4. Neither the name of the University nor the names of its contributors
  42  *    may be used to endorse or promote products derived from this software
  43  *    without specific prior written permission.
  44  *
  45  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  46  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  47  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  48  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  49  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  50  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  51  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  52  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  53  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  54  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  55  * SUCH DAMAGE.
  56  */
  57
  58
  59 #include <sys/types.h>
  60 #include <sys/stat.h>
  61
  62 #include <mach/mach.h>
  63 #include <mach/mach_traps.h>
  64
  65 #include <errno.h>
  66 #include <fcntl.h>
  67 #include <limits.h>
  68 #include <stddef.h>
  69 #include <stdio.h>
  70 #include <unistd.h>
  71
  72 #include <db.h>
  73 #include "recno.h"
  74
  75 DB *
  76 __rec_open(fname, flags, mode, openinfo, dflags)
  77         const char *fname;
  78         int flags, mode, dflags;
  79         const RECNOINFO *openinfo;
  80 {
  81         BTREE *t;
  82         BTREEINFO btopeninfo;
  83         DB *dbp;
  84         PAGE *h;
  85         struct stat sb;
  86         int rfd, sverrno;
  87
  88         /* Open the user's file -- if this fails, we're done. */
  89         if (fname != NULL && (rfd = open(fname, flags, mode)) < 0)
  90                 return (NULL);
  91
  92         /* Create a btree in memory (backed by disk). */
  93         dbp = NULL;
  94         if (openinfo) {
  95                 if (openinfo->flags & ~(R_FIXEDLEN | R_NOKEY | R_SNAPSHOT))
  96                         goto einval;
  97                 btopeninfo.flags = 0;
  98                 btopeninfo.cachesize = openinfo->cachesize;
  99                 btopeninfo.maxkeypage = 0;
 100                 btopeninfo.minkeypage = 0;
 101                 btopeninfo.psize = openinfo->psize;
 102                 btopeninfo.compare = NULL;
 103                 btopeninfo.prefix = NULL;
 104                 btopeninfo.lorder = openinfo->lorder;
 105                 dbp = __bt_open(openinfo->bfname,
 106                     O_RDWR, S_IRUSR | S_IWUSR, &btopeninfo, dflags);
 107         } else
 108                 dbp = __bt_open(NULL, O_RDWR, S_IRUSR | S_IWUSR, NULL, dflags);
 109         if (dbp == NULL)
 110                 goto err;
 111
 112         /*
 113          * Some fields in the tree structure are recno specific.  Fill them
 114          * in and make the btree structure look like a recno structure.  We
 115          * don't change the bt_ovflsize value, it's close enough and slightly
 116          * bigger.
 117          */
 118         t = dbp->internal;
 119         if (openinfo) {
 120                 if (openinfo->flags & R_FIXEDLEN) {
 121                         SET(t, R_FIXLEN);
 122                         t->bt_reclen = openinfo->reclen;
 123                         if (t->bt_reclen == 0)
 124                                 goto einval;
 125                 }
 126                 t->bt_bval = openinfo->bval;
 127         } else
 128                 t->bt_bval = '\n';
 129
 130         SET(t, R_RECNO);
 131         if (fname == NULL)
 132                 SET(t, R_EOF | R_INMEM);
 133         else
 134                 t->bt_rfd = rfd;
 135         t->bt_rcursor = 0;
 136
 137         if (fname != NULL) {
 138                 /*
 139                  * In 4.4BSD, stat(2) returns true for ISSOCK on pipes.
 140                  * Unfortunately, that's not portable, so we use lseek
 141                  * and check the errno values.
 142                  */
 143                 errno = 0;
 144                 if (lseek(rfd, (off_t)0, SEEK_CUR) == -1 && errno == ESPIPE) {
 145                         switch (flags & O_ACCMODE) {
 146                         case O_RDONLY:
 147                                 SET(t, R_RDONLY);
 148                                 break;
 149                         default:
 150                                 goto einval;
 151                         }
 152 slow:                   if ((t->bt_rfp = fdopen(rfd, "r")) == NULL)
 153                                 goto err;
 154                         SET(t, R_CLOSEFP);
 155                         t->bt_irec =
 156                             ISSET(t, R_FIXLEN) ? __rec_fpipe : __rec_vpipe;
 157                 } else {
 158                         switch (flags & O_ACCMODE) {
 159                         case O_RDONLY:
 160                                 SET(t, R_RDONLY);
 161                                 break;
 162                         case O_RDWR:
 163                                 break;
 164                         default:
 165                                 goto einval;
 166                         }
 167
 168                         if (fstat(rfd, &sb))
 169                                 goto err;
 170                         /*
 171                          * Kluge -- we'd like to test to see if the file is too
 172                          * big to mmap.  Since, we don't know what size or type
 173                          * off_t's or size_t's are, what the largest unsigned
 174                          * integral type is, or what random insanity the local
 175                          * C compiler will perpetrate, doing the comparison in
 176                          * a portable way is flatly impossible.  Hope that mmap
 177                          * fails if the file is too large.
 178                          */
 179                         if (sb.st_size == 0)
 180                                 SET(t, R_EOF);
 181                         else {
 182                                 t->bt_msize = sb.st_size;
 183                                 if ( (map_fd(rfd, 0, (vm_offset_t *)
 184                                     &t->bt_smap, TRUE, t->bt_msize)
 185                                      != KERN_SUCCESS)
 186                                 ||   (vm_protect(mach_task_self(), (vm_offset_t)
 187                                     t->bt_smap,  t->bt_msize, TRUE,
 188                                     VM_PROT_READ) != KERN_SUCCESS) )
 189                                         goto slow;
 190                                 t->bt_cmap = t->bt_smap;
 191                                 t->bt_emap = t->bt_smap + sb.st_size;
 192                                 t->bt_irec = ISSET(t, R_FIXLEN) ?
 193                                     __rec_fmap : __rec_vmap;
 194                                 SET(t, R_MEMMAPPED);
 195                         }
 196                 }
 197         }
 198
 199         /* Use the recno routines. */
 200         dbp->close = __rec_close;
 201         dbp->del = __rec_delete;
 202         dbp->fd = __rec_fd;
 203         dbp->get = __rec_get;
 204         dbp->put = __rec_put;
 205         dbp->seq = __rec_seq;
 206         dbp->sync = __rec_sync;
 207
 208         /* If the root page was created, reset the flags. */
 209         if ((h = mpool_get(t->bt_mp, P_ROOT, 0)) == NULL)
 210                 goto err;
 211         if ((h->flags & P_TYPE) == P_BLEAF) {
 212                 h->flags = h->flags & ~P_TYPE | P_RLEAF;
 213                 mpool_put(t->bt_mp, h, MPOOL_DIRTY);
 214         } else
 215                 mpool_put(t->bt_mp, h, 0);
 216
 217         if (openinfo && openinfo->flags & R_SNAPSHOT &&
 218             !ISSET(t, R_EOF | R_INMEM) &&
 219             t->bt_irec(t, MAX_REC_NUMBER) == RET_ERROR)
 220                 goto err;
 221         return (dbp);
 222
 223 einval: errno = EINVAL;
 224 err:    sverrno = errno;
 225         if (dbp != NULL)
 226                 (void)__bt_close(dbp);
 227         if (fname != NULL)
 228                 (void)close(rfd);
 229         errno = sverrno;
 230         return (NULL);
 231 }
 232
 233 int
 234 __rec_fd(dbp)
 235         const DB *dbp;
 236 {
 237         BTREE *t;
 238
 239         t = dbp->internal;
 240
 241         /* Toss any page pinned across calls. */
 242         if (t->bt_pinned != NULL) {
 243                 mpool_put(t->bt_mp, t->bt_pinned, 0);
 244                 t->bt_pinned = NULL;
 245         }
 246
 247         /* In-memory database can't have a file descriptor. */
 248         if (ISSET(t, R_INMEM)) {
 249                 errno = ENOENT;
 250                 return (-1);
 251         }
 252         return (t->bt_rfd);
 253 }