rec_open.c revision 330897 
1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
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 * 4. 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 defined(LIBC_SCCS) && !defined(lint)
36static char sccsid[] = "@(#)rec_open.c	8.10 (Berkeley) 9/1/94";
37#endif /* LIBC_SCCS and not lint */
38#include <sys/cdefs.h>
39__FBSDID("$FreeBSD: stable/11/lib/libc/db/recno/rec_open.c 330897 2018-03-14 03:19:51Z eadler $");
40
41#include "namespace.h"
42#include <sys/types.h>
43#include <sys/mman.h>
44#include <sys/stat.h>
45
46#include <errno.h>
47#include <fcntl.h>
48#include <limits.h>
49#include <stddef.h>
50#include <stdio.h>
51#include <unistd.h>
52#include "un-namespace.h"
53
54#include <db.h>
55#include "recno.h"
56
57DB *
58__rec_open(const char *fname, int flags, int mode, const RECNOINFO *openinfo,
59    int dflags)
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 | O_CLOEXEC, 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			}
131slow:			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)) == MAP_FAILED)
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
211einval:	errno = EINVAL;
212err:	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
221int
222__rec_fd(const DB *dbp)
223{
224	BTREE *t;
225
226	t = dbp->internal;
227
228	/* Toss any page pinned across calls. */
229	if (t->bt_pinned != NULL) {
230		mpool_put(t->bt_mp, t->bt_pinned, 0);
231		t->bt_pinned = NULL;
232	}
233
234	/* In-memory database can't have a file descriptor. */
235	if (F_ISSET(t, R_INMEM)) {
236		errno = ENOENT;
237		return (-1);
238	}
239	return (t->bt_rfd);
240}
241