1 /*-
2 * Copyright (c) 1990, 1993
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 * %sccs.include.redist.c%
9 */
10
11 #if defined(LIBC_SCCS) && !defined(lint)
12 static char sccsid[] = "@(#)rec_open.c 8.6 (Berkeley) 02/22/94";
13 #endif /* LIBC_SCCS and not lint */
14
15 #include <sys/types.h>
16 #include <sys/mman.h>
17 #include <sys/stat.h>
18
19 #include <errno.h>
20 #include <fcntl.h>
21 #include <limits.h>
22 #include <stddef.h>
23 #include <stdio.h>
24 #include <unistd.h>
25
26 #include <db.h>
27 #include "recno.h"
28
29 DB *
__rec_open(fname,flags,mode,openinfo,dflags)30 __rec_open(fname, flags, mode, openinfo, dflags)
31 const char *fname;
32 int flags, mode, dflags;
33 const RECNOINFO *openinfo;
34 {
35 BTREE *t;
36 BTREEINFO btopeninfo;
37 DB *dbp;
38 PAGE *h;
39 struct stat sb;
40 int rfd, sverrno;
41
42 /* Open the user's file -- if this fails, we're done. */
43 if (fname != NULL && (rfd = open(fname, flags, mode)) < 0)
44 return (NULL);
45
46 /* Create a btree in memory (backed by disk). */
47 dbp = NULL;
48 if (openinfo) {
49 if (openinfo->flags & ~(R_FIXEDLEN | R_NOKEY | R_SNAPSHOT))
50 goto einval;
51 btopeninfo.flags = 0;
52 btopeninfo.cachesize = openinfo->cachesize;
53 btopeninfo.maxkeypage = 0;
54 btopeninfo.minkeypage = 0;
55 btopeninfo.psize = openinfo->psize;
56 btopeninfo.compare = NULL;
57 btopeninfo.prefix = NULL;
58 btopeninfo.lorder = openinfo->lorder;
59 dbp = __bt_open(openinfo->bfname,
60 O_RDWR, S_IRUSR | S_IWUSR, &btopeninfo, dflags);
61 } else
62 dbp = __bt_open(NULL, O_RDWR, S_IRUSR | S_IWUSR, NULL, dflags);
63 if (dbp == NULL)
64 goto err;
65
66 /*
67 * Some fields in the tree structure are recno specific. Fill them
68 * in and make the btree structure look like a recno structure. We
69 * don't change the bt_ovflsize value, it's close enough and slightly
70 * bigger.
71 */
72 t = dbp->internal;
73 if (openinfo) {
74 if (openinfo->flags & R_FIXEDLEN) {
75 SET(t, R_FIXLEN);
76 t->bt_reclen = openinfo->reclen;
77 if (t->bt_reclen == 0)
78 goto einval;
79 }
80 t->bt_bval = openinfo->bval;
81 } else
82 t->bt_bval = '\n';
83
84 SET(t, R_RECNO);
85 if (fname == NULL)
86 SET(t, R_EOF | R_INMEM);
87 else
88 t->bt_rfd = rfd;
89 t->bt_rcursor = 0;
90
91 if (fname != NULL) {
92 /*
93 * In 4.4BSD, stat(2) returns true for ISSOCK on pipes.
94 * Unfortunately, that's not portable, so we use lseek
95 * and check the errno values.
96 */
97 errno = 0;
98 if (lseek(rfd, (off_t)0, SEEK_CUR) == -1 && errno == ESPIPE) {
99 switch (flags & O_ACCMODE) {
100 case O_RDONLY:
101 SET(t, R_RDONLY);
102 break;
103 default:
104 goto einval;
105 }
106 slow: if ((t->bt_rfp = fdopen(rfd, "r")) == NULL)
107 goto err;
108 SET(t, R_CLOSEFP);
109 t->bt_irec =
110 ISSET(t, R_FIXLEN) ? __rec_fpipe : __rec_vpipe;
111 } else {
112 switch (flags & O_ACCMODE) {
113 case O_RDONLY:
114 SET(t, R_RDONLY);
115 break;
116 case O_RDWR:
117 break;
118 default:
119 goto einval;
120 }
121
122 if (fstat(rfd, &sb))
123 goto err;
124 /*
125 * Kluge -- we'd like to test to see if the file is too
126 * big to mmap. Since, we don't know what size or type
127 * off_t's or size_t's are, what the largest unsigned
128 * integral type is, or what random insanity the local
129 * C compiler will perpetrate, doing the comparison in
130 * a portable way is flatly impossible. Hope that mmap
131 * fails if the file is too large.
132 */
133 if (sb.st_size == 0)
134 SET(t, R_EOF);
135 else {
136 t->bt_msize = sb.st_size;
137 if ((t->bt_smap = mmap(NULL, t->bt_msize,
138 PROT_READ, MAP_PRIVATE, rfd,
139 (off_t)0)) == (caddr_t)-1)
140 goto slow;
141 t->bt_cmap = t->bt_smap;
142 t->bt_emap = t->bt_smap + sb.st_size;
143 t->bt_irec = ISSET(t, R_FIXLEN) ?
144 __rec_fmap : __rec_vmap;
145 SET(t, R_MEMMAPPED);
146 }
147 }
148 }
149
150 /* Use the recno routines. */
151 dbp->close = __rec_close;
152 dbp->del = __rec_delete;
153 dbp->fd = __rec_fd;
154 dbp->get = __rec_get;
155 dbp->put = __rec_put;
156 dbp->seq = __rec_seq;
157 dbp->sync = __rec_sync;
158
159 /* If the root page was created, reset the flags. */
160 if ((h = mpool_get(t->bt_mp, P_ROOT, 0)) == NULL)
161 goto err;
162 if ((h->flags & P_TYPE) == P_BLEAF) {
163 h->flags = h->flags & ~P_TYPE | P_RLEAF;
164 mpool_put(t->bt_mp, h, MPOOL_DIRTY);
165 } else
166 mpool_put(t->bt_mp, h, 0);
167
168 if (openinfo && openinfo->flags & R_SNAPSHOT &&
169 !ISSET(t, R_EOF | R_INMEM) &&
170 t->bt_irec(t, MAX_REC_NUMBER) == RET_ERROR)
171 goto err;
172 return (dbp);
173
174 einval: errno = EINVAL;
175 err: sverrno = errno;
176 if (dbp != NULL)
177 (void)__bt_close(dbp);
178 if (fname != NULL)
179 (void)close(rfd);
180 errno = sverrno;
181 return (NULL);
182 }
183
184 int
__rec_fd(dbp)185 __rec_fd(dbp)
186 const DB *dbp;
187 {
188 BTREE *t;
189
190 t = dbp->internal;
191
192 /* Toss any page pinned across calls. */
193 if (t->bt_pinned != NULL) {
194 mpool_put(t->bt_mp, t->bt_pinned, 0);
195 t->bt_pinned = NULL;
196 }
197
198 /* In-memory database can't have a file descriptor. */
199 if (ISSET(t, R_INMEM)) {
200 errno = ENOENT;
201 return (-1);
202 }
203 return (t->bt_rfd);
204 }
205