xref: /netbsd/external/bsd/nvi/dist/common/vi_db1.c (revision 099ed871)
1 /*-
2  * Copyright (c) 1992, 1993, 1994
3  *	The Regents of the University of California.  All rights reserved.
4  * Copyright (c) 1992, 1993, 1994, 1995, 1996
5  *	Keith Bostic.  All rights reserved.
6  *
7  * See the LICENSE file for redistribution information.
8  */
9 
10 #include "config.h"
11 
12 #include <sys/cdefs.h>
13 #if 0
14 #ifndef lint
15 static const char sccsid[] = "Id: db1.c,v 10.1 2002/03/09 12:53:57 skimo Exp  (Berkeley) Date: 2002/03/09 12:53:57 ";
16 #endif /* not lint */
17 #else
18 __RCSID("$NetBSD: vi_db1.c,v 1.10 2018/08/07 11:25:45 rin Exp $");
19 #endif
20 
21 #include <sys/types.h>
22 #include <sys/queue.h>
23 #include <sys/time.h>
24 #include <sys/stat.h>
25 
26 #include <bitstring.h>
27 #include <errno.h>
28 #include <fcntl.h>
29 #include <limits.h>
30 #include <stdio.h>
31 #include <string.h>
32 
33 #include "common.h"
34 #include "../vi/vi.h"
35 #include "dbinternal.h"
36 
37 /*
38  * db_eget --
39  *	Front-end to db_get, special case handling for empty files.
40  *
41  * PUBLIC: int db_eget __P((SCR *, db_recno_t, CHAR_T **, size_t *, int *));
42  */
43 int
db_eget(SCR * sp,db_recno_t lno,CHAR_T ** pp,size_t * lenp,int * isemptyp)44 db_eget(SCR *sp, db_recno_t lno, CHAR_T **pp, size_t *lenp, int *isemptyp)
45 
46 	               				/* Line number. */
47 	            				/* Pointer store. */
48 	             				/* Length store. */
49 
50 {
51 	db_recno_t l1;
52 
53 	if (isemptyp != NULL)
54 		*isemptyp = 0;
55 
56 	/* If the line exists, simply return it. */
57 	if (!db_get(sp, lno, 0, pp, lenp))
58 		return (0);
59 
60 	/*
61 	 * If the user asked for line 0 or line 1, i.e. the only possible
62 	 * line in an empty file, find the last line of the file; db_last
63 	 * fails loudly.
64 	 */
65 	if ((lno == 0 || lno == 1) && db_last(sp, &l1))
66 		return (1);
67 
68 	/* If the file isn't empty, fail loudly. */
69 	if ((lno != 0 && lno != 1) || l1 != 0) {
70 		db_err(sp, lno);
71 		return (1);
72 	}
73 
74 	if (isemptyp != NULL)
75 		*isemptyp = 1;
76 
77 	return (1);
78 }
79 
80 /*
81  * db_get --
82  *	Look in the text buffers for a line, followed by the cache, followed
83  *	by the database.
84  *
85  * PUBLIC: int db_get __P((SCR *, db_recno_t, u_int32_t, CHAR_T **, size_t *));
86  */
87 int
db_get(SCR * sp,db_recno_t lno,u_int32_t flags,CHAR_T ** pp,size_t * lenp)88 db_get(SCR *sp, db_recno_t lno, u_int32_t flags, CHAR_T **pp, size_t *lenp)
89 
90 	               				/* Line number. */
91 
92 	            				/* Pointer store. */
93 	             				/* Length store. */
94 {
95 	DBT data, key;
96 	EXF *ep;
97 	TEXT *tp;
98 	db_recno_t l1, l2;
99 	const CHAR_T *wp;
100 	size_t wlen;
101 
102 	/*
103 	 * The underlying recno stuff handles zero by returning NULL, but
104 	 * have to have an OOB condition for the look-aside into the input
105 	 * buffer anyway.
106 	 */
107 	if (lno == 0)
108 		goto err1;
109 
110 	/* Check for no underlying file. */
111 	if ((ep = sp->ep) == NULL) {
112 		ex_emsg(sp, NULL, EXM_NOFILEYET);
113 		goto err3;
114 	}
115 
116 	if (LF_ISSET(DBG_NOCACHE))
117 		goto nocache;
118 
119 	/*
120 	 * Look-aside into the TEXT buffers and see if the line we want
121 	 * is there.
122 	 */
123 	if (F_ISSET(sp, SC_TINPUT)) {
124 		l1 = TAILQ_FIRST(&sp->tiq)->lno;
125 		l2 = TAILQ_LAST(&sp->tiq, _texth)->lno;
126 		if (l1 <= lno && l2 >= lno) {
127 #if defined(DBDEBUG) && defined(TRACE)
128 			vtrace(
129 			    "retrieve TEXT buffer line %lu\n", (u_long)lno);
130 #endif
131 			for (tp = TAILQ_FIRST(&sp->tiq);
132 			    tp->lno != lno; tp = TAILQ_NEXT(tp, q));
133 			if (lenp != NULL)
134 				*lenp = tp->len;
135 			if (pp != NULL)
136 				*pp = tp->lb;
137 			return (0);
138 		}
139 		/*
140 		 * Adjust the line number for the number of lines used
141 		 * by the text input buffers.
142 		 */
143 		if (lno > l2)
144 			lno -= l2 - l1;
145 	}
146 
147 	/* Look-aside into the cache, and see if the line we want is there. */
148 	if (lno == sp->c_lno) {
149 #if defined(DBDEBUG) && defined(TRACE)
150 		vtrace("retrieve cached line %lu\n", (u_long)lno);
151 #endif
152 		if (lenp != NULL)
153 			*lenp = sp->c_len;
154 		if (pp != NULL)
155 			*pp = sp->c_lp;
156 		return (0);
157 	}
158 	sp->c_lno = OOBLNO;
159 
160 nocache:
161 	/* Get the line from the underlying database. */
162 	key.data = &lno;
163 	key.size = sizeof(lno);
164 	switch (ep->db->get(ep->db, &key, &data, 0)) {
165         case -1:
166 		goto err2;
167 	case 1:
168 err1:		if (LF_ISSET(DBG_FATAL))
169 err2:			db_err(sp, lno);
170 alloc_err:
171 err3:		if (lenp != NULL)
172 			*lenp = 0;
173 		if (pp != NULL)
174 			*pp = NULL;
175 		return (1);
176 	default:
177 		break;
178 	}
179 
180 	if (FILE2INT(sp, data.data, data.size, wp, wlen)) {
181 	    if (!F_ISSET(sp, SC_CONV_ERROR)) {
182 		F_SET(sp, SC_CONV_ERROR);
183 		msgq(sp, M_ERR, "324|Conversion error on line %d", lno);
184 	    }
185 	    goto err3;
186 	}
187 
188 	/* Reset the cache. */
189 	if (wp != data.data) {
190 	    BINC_GOTOW(sp, sp->c_lp, sp->c_blen, wlen);
191 	    MEMCPYW(sp->c_lp, wp, wlen);
192 	} else
193 	    sp->c_lp = data.data;
194 	sp->c_lno = lno;
195 	sp->c_len = wlen;
196 
197 #if defined(DBDEBUG) && defined(TRACE)
198 	vtrace("retrieve DB line %lu\n", (u_long)lno);
199 #endif
200 	if (lenp != NULL)
201 		*lenp = wlen;
202 	if (pp != NULL)
203 		*pp = sp->c_lp;
204 	return (0);
205 }
206 
207 /*
208  * db_delete --
209  *	Delete a line from the file.
210  *
211  * PUBLIC: int db_delete __P((SCR *, db_recno_t));
212  */
213 int
db_delete(SCR * sp,db_recno_t lno)214 db_delete(SCR *sp, db_recno_t lno)
215 {
216 	DBT key;
217 	EXF *ep;
218 
219 #if defined(DBDEBUG) && defined(TRACE)
220 	vtrace("delete line %lu\n", (u_long)lno);
221 #endif
222 	/* Check for no underlying file. */
223 	if ((ep = sp->ep) == NULL) {
224 		ex_emsg(sp, NULL, EXM_NOFILEYET);
225 		return (1);
226 	}
227 	if (ep->l_win && ep->l_win != sp->wp) {
228 		ex_emsg(sp, NULL, EXM_LOCKED);
229 		return 1;
230 	}
231 
232 	/* Update marks, @ and global commands. */
233 	if (mark_insdel(sp, LINE_DELETE, lno))
234 		return (1);
235 	if (ex_g_insdel(sp, LINE_DELETE, lno))
236 		return (1);
237 
238 	/* Log change. */
239 	log_line(sp, lno, LOG_LINE_DELETE_B);
240 
241 	/* Update file. */
242 	key.data = &lno;
243 	key.size = sizeof(lno);
244 	sp->db_error = ep->db->del(ep->db, &key, 0);
245 	if (sp->db_error != 0) {
246 		if (sp->db_error == -1)
247 			sp->db_error = errno;
248 
249 		msgq(sp, M_DBERR, "003|unable to delete line %lu",
250 		    (u_long)lno);
251 		return (1);
252 	}
253 
254 	/* Flush the cache, update line count, before screen update. */
255 	update_cache(sp, LINE_DELETE, lno);
256 
257 	/* File now modified. */
258 	if (F_ISSET(ep, F_FIRSTMODIFY))
259 		(void)rcv_init(sp);
260 	F_SET(ep, F_MODIFIED);
261 
262 	/* Log after change. */
263 	log_line(sp, lno, LOG_LINE_DELETE_F);
264 
265 	/* Update screen. */
266 	return (scr_update(sp, lno, LINE_DELETE, 1));
267 }
268 
269 /*
270  * db_append --
271  *	Append a line into the file.
272  *
273  * PUBLIC: int db_append __P((SCR *, int, db_recno_t, const CHAR_T *, size_t));
274  */
275 int
db_append(SCR * sp,int update,db_recno_t lno,const CHAR_T * p,size_t len)276 db_append(SCR *sp, int update, db_recno_t lno, const CHAR_T *p, size_t len)
277 {
278 	DBT data, key;
279 	EXF *ep;
280 	const char *fp;
281 	size_t flen;
282 	int rval;
283 
284 #if defined(DBDEBUG) && defined(TRACE)
285 	vtrace("append to %lu: len %u {%.*s}\n", lno, len, MIN(len, 20), p);
286 #endif
287 	/* Check for no underlying file. */
288 	if ((ep = sp->ep) == NULL) {
289 		ex_emsg(sp, NULL, EXM_NOFILEYET);
290 		return (1);
291 	}
292 	if (ep->l_win && ep->l_win != sp->wp) {
293 		ex_emsg(sp, NULL, EXM_LOCKED);
294 		return 1;
295 	}
296 
297 	/* Log before change. */
298 	log_line(sp, lno + 1, LOG_LINE_APPEND_B);
299 
300 	INT2FILE(sp, p, len, fp, flen);
301 
302 	/* Update file. */
303 	key.data = &lno;
304 	key.size = sizeof(lno);
305 	data.data = __UNCONST(fp);
306 	data.size = flen;
307 	if (ep->db->put(ep->db, &key, &data, R_IAFTER)) {
308 		msgq(sp, M_DBERR, "004|unable to append to line %lu",
309 			(u_long)lno);
310 		return (1);
311 	}
312 
313 	/* Flush the cache, update line count, before screen update. */
314 	update_cache(sp, LINE_INSERT, lno);
315 
316 	/* File now dirty. */
317 	if (F_ISSET(ep, F_FIRSTMODIFY))
318 		(void)rcv_init(sp);
319 	F_SET(ep, F_MODIFIED);
320 
321 	/* Log after change. */
322 	log_line(sp, lno + 1, LOG_LINE_APPEND_F);
323 
324 	/* Update marks, @ and global commands. */
325 	rval = 0;
326 	if (mark_insdel(sp, LINE_INSERT, lno + 1))
327 		rval = 1;
328 	if (ex_g_insdel(sp, LINE_INSERT, lno + 1))
329 		rval = 1;
330 
331 	/*
332 	 * Update screen.
333 	 *
334 	 * XXX
335 	 * Nasty hack.  If multiple lines are input by the user, they aren't
336 	 * committed until an <ESC> is entered.  The problem is the screen was
337 	 * updated/scrolled as each line was entered.  So, when this routine
338 	 * is called to copy the new lines from the cut buffer into the file,
339 	 * it has to know not to update the screen again.
340 	 */
341 	return (scr_update(sp, lno, LINE_APPEND, update) || rval);
342 }
343 
344 /*
345  * db_insert --
346  *	Insert a line into the file.
347  *
348  * PUBLIC: int db_insert __P((SCR *, db_recno_t, CHAR_T *, size_t));
349  */
350 int
db_insert(SCR * sp,db_recno_t lno,CHAR_T * p,size_t len)351 db_insert(SCR *sp, db_recno_t lno, CHAR_T *p, size_t len)
352 {
353 	DBT data, key;
354 	EXF *ep;
355 	const char *fp;
356 	size_t flen;
357 	int rval;
358 
359 #if defined(DBDEBUG) && defined(TRACE)
360 	vtrace("insert before %lu: len %lu {%.*s}\n",
361 	    (u_long)lno, (u_long)len, MIN(len, 20), p);
362 #endif
363 	/* Check for no underlying file. */
364 	if ((ep = sp->ep) == NULL) {
365 		ex_emsg(sp, NULL, EXM_NOFILEYET);
366 		return (1);
367 	}
368 	if (ep->l_win && ep->l_win != sp->wp) {
369 		ex_emsg(sp, NULL, EXM_LOCKED);
370 		return 1;
371 	}
372 
373 	/* Log before change. */
374 	log_line(sp, lno, LOG_LINE_APPEND_B);
375 
376 	INT2FILE(sp, p, len, fp, flen);
377 
378 	/* Update file. */
379 	key.data = &lno;
380 	key.size = sizeof(lno);
381 	data.data = __UNCONST(fp);
382 	data.size = flen;
383 	if (ep->db->put(ep->db, &key, &data, R_IBEFORE)) {
384 		msgq(sp, M_SYSERR,
385 		    "005|unable to insert at line %lu", (u_long)lno);
386 		return (1);
387 	}
388 
389 	/* Flush the cache, update line count, before screen update. */
390 	update_cache(sp, LINE_INSERT, lno);
391 
392 	/* File now dirty. */
393 	if (F_ISSET(ep, F_FIRSTMODIFY))
394 		(void)rcv_init(sp);
395 	F_SET(ep, F_MODIFIED);
396 
397 	/* Log after change. */
398 	log_line(sp, lno, LOG_LINE_APPEND_F);
399 
400 	/* Update marks, @ and global commands. */
401 	rval = 0;
402 	if (mark_insdel(sp, LINE_INSERT, lno))
403 		rval = 1;
404 	if (ex_g_insdel(sp, LINE_INSERT, lno))
405 		rval = 1;
406 
407 	/* Update screen. */
408 	return (scr_update(sp, lno, LINE_INSERT, 1) || rval);
409 }
410 
411 /*
412  * db_set --
413  *	Store a line in the file.
414  *
415  * PUBLIC: int db_set __P((SCR *, db_recno_t, const CHAR_T *, size_t));
416  */
417 int
db_set(SCR * sp,db_recno_t lno,const CHAR_T * p,size_t len)418 db_set(SCR *sp, db_recno_t lno, const CHAR_T *p, size_t len)
419 {
420 	DBT data, key;
421 	EXF *ep;
422 	const char *fp;
423 	size_t flen;
424 
425 #if defined(DBDEBUG) && defined(TRACE)
426 	vtrace("replace line %lu: len %lu {%.*s}\n",
427 	    (u_long)lno, (u_long)len, MIN(len, 20), p);
428 #endif
429 	/* Check for no underlying file. */
430 	if ((ep = sp->ep) == NULL) {
431 		ex_emsg(sp, NULL, EXM_NOFILEYET);
432 		return (1);
433 	}
434 	if (ep->l_win && ep->l_win != sp->wp) {
435 		ex_emsg(sp, NULL, EXM_LOCKED);
436 		return 1;
437 	}
438 
439 	/* Log before change. */
440 	log_line(sp, lno, LOG_LINE_RESET_B);
441 
442 	INT2FILE(sp, p, len, fp, flen);
443 
444 	/* Update file. */
445 	key.data = &lno;
446 	key.size = sizeof(lno);
447 	data.data = __UNCONST(fp);
448 	data.size = flen;
449 	sp->db_error =
450 		ep->db->put(ep->db, &key, &data, 0);
451 	if (sp->db_error != 0) {
452 		if (sp->db_error == -1)
453 			sp->db_error = errno;
454 
455 		msgq(sp, M_DBERR, "006|unable to store line %lu", (u_long)lno);
456 		return (1);
457 	}
458 
459 	/* Flush the cache, before logging or screen update. */
460 	update_cache(sp, LINE_RESET, lno);
461 
462 	/* File now dirty. */
463 	if (F_ISSET(ep, F_FIRSTMODIFY))
464 		(void)rcv_init(sp);
465 	F_SET(ep, F_MODIFIED);
466 
467 	/* Log after change. */
468 	log_line(sp, lno, LOG_LINE_RESET_F);
469 
470 	/* Update screen. */
471 	return (scr_update(sp, lno, LINE_RESET, 1));
472 }
473 
474 /*
475  * db_exist --
476  *	Return if a line exists.
477  *
478  * PUBLIC: int db_exist __P((SCR *, db_recno_t));
479  */
480 int
db_exist(SCR * sp,db_recno_t lno)481 db_exist(SCR *sp, db_recno_t lno)
482 {
483 	EXF *ep;
484 
485 	/* Check for no underlying file. */
486 	if ((ep = sp->ep) == NULL) {
487 		ex_emsg(sp, NULL, EXM_NOFILEYET);
488 		return (1);
489 	}
490 
491 	if (lno == OOBLNO)
492 		return (0);
493 
494 	/*
495 	 * Check the last-line number cache.  Adjust the cached line
496 	 * number for the lines used by the text input buffers.
497 	 */
498 	if (ep->c_nlines != OOBLNO)
499 		return (lno <= (F_ISSET(sp, SC_TINPUT) ?
500 		    ep->c_nlines + (TAILQ_LAST(&sp->tiq, _texth)->lno -
501 		    TAILQ_FIRST(&sp->tiq)->lno) : ep->c_nlines));
502 
503 	/* Go get the line. */
504 	return (!db_get(sp, lno, 0, NULL, NULL));
505 }
506 
507 /*
508  * db_last --
509  *	Return the number of lines in the file.
510  *
511  * PUBLIC: int db_last __P((SCR *, db_recno_t *));
512  */
513 int
db_last(SCR * sp,db_recno_t * lnop)514 db_last(SCR *sp, db_recno_t *lnop)
515 {
516 	DBT data, key;
517 	EXF *ep;
518 	db_recno_t lno;
519 	const CHAR_T *wp;
520 	size_t wlen;
521 
522 	/* Check for no underlying file. */
523 	if ((ep = sp->ep) == NULL) {
524 		ex_emsg(sp, NULL, EXM_NOFILEYET);
525 		return (1);
526 	}
527 
528 	/*
529 	 * Check the last-line number cache.  Adjust the cached line
530 	 * number for the lines used by the text input buffers.
531 	 */
532 	if (ep->c_nlines != OOBLNO) {
533 		*lnop = ep->c_nlines;
534 		if (F_ISSET(sp, SC_TINPUT))
535 			*lnop += TAILQ_LAST(&sp->tiq, _texth)->lno -
536 			    TAILQ_FIRST(&sp->tiq)->lno;
537 		return (0);
538 	}
539 
540 	key.data = &lno;
541 	key.size = sizeof(lno);
542 
543 	sp->db_error = ep->db->seq(ep->db, &key, &data, R_LAST);
544 	switch (sp->db_error) {
545 	case 1:
546 		*lnop = 0;
547 		return (0);
548 	case -1:
549 		sp->db_error = errno;
550 alloc_err:
551 		msgq(sp, M_DBERR, "007|unable to get last line");
552 		*lnop = 0;
553 		return (1);
554 	default:
555 		break;
556 	}
557 
558 	memcpy(&lno, key.data, sizeof(lno));
559 
560 	if (lno != sp->c_lno) {
561 	    FILE2INT(sp, data.data, data.size, wp, wlen);
562 
563 	    /* Fill the cache. */
564 	    if (wp != data.data) {
565 		BINC_GOTOW(sp, sp->c_lp, sp->c_blen, wlen);
566 		MEMCPYW(sp->c_lp, wp, wlen);
567 	    } else
568 		sp->c_lp = data.data;
569 	    sp->c_lno = lno;
570 	    sp->c_len = wlen;
571 	}
572 	ep->c_nlines = lno;
573 
574 	/* Return the value. */
575 	*lnop = (F_ISSET(sp, SC_TINPUT) &&
576 	    TAILQ_LAST(&sp->tiq, _texth)->lno > lno ?
577 	    TAILQ_LAST(&sp->tiq, _texth)->lno : lno);
578 	return (0);
579 }
580 
581 /*
582  * db_err --
583  *	Report a line error.
584  *
585  * PUBLIC: void db_err __P((SCR *, db_recno_t));
586  */
587 void
db_err(SCR * sp,db_recno_t lno)588 db_err(SCR *sp, db_recno_t lno)
589 {
590 	msgq(sp, M_ERR,
591 	    "008|Error: unable to retrieve line %lu", (u_long)lno);
592 }
593 
594 /*
595  * scr_update --
596  *	Update all of the screens that are backed by the file that
597  *	just changed.
598  * PUBLIC: int scr_update __P((SCR *sp, db_recno_t lno,
599  * PUBLIC:                      lnop_t op, int current));
600  */
601 int
scr_update(SCR * sp,db_recno_t lno,lnop_t op,int current)602 scr_update(SCR *sp, db_recno_t lno, lnop_t op, int current)
603 {
604 	EXF *ep;
605 	SCR *tsp;
606 	WIN *wp;
607 
608 	if (F_ISSET(sp, SC_EX))
609 		return (0);
610 
611 	/* XXXX goes outside of window */
612 	ep = sp->ep;
613 	if (ep->refcnt != 1)
614 		TAILQ_FOREACH(wp, &sp->gp->dq, q)
615 			TAILQ_FOREACH(tsp, &wp->scrq, q)
616 				if (sp != tsp && tsp->ep == ep)
617 					if (vs_change(tsp, lno, op))
618 						return (1);
619 	return (current ? vs_change(sp, lno, op) : 0);
620 }
621 
622 /*
623  * PUBLIC: void update_cache __P((SCR *sp, lnop_t op, db_recno_t lno));
624  */
625 void
update_cache(SCR * sp,lnop_t op,db_recno_t lno)626 update_cache(SCR *sp, lnop_t op, db_recno_t lno)
627 {
628 	SCR* scrp;
629 	EXF *ep;
630 
631 	ep = sp->ep;
632 
633 	/* Flush the cache, update line count, before screen update. */
634 	/* The flushing is probably not needed, since it was incorrect
635 	 * for db_insert.  It might be better to adjust it, like
636 	 * marks, @ and global
637 	 */
638 	TAILQ_FOREACH(scrp, &ep->scrq, eq)
639 		switch (op) {
640 		case LINE_INSERT:
641 		case LINE_DELETE:
642 			if (lno <= scrp->c_lno)
643 				scrp->c_lno = OOBLNO;
644 			break;
645 		case LINE_RESET:
646 			if (lno == scrp->c_lno)
647 				scrp->c_lno = OOBLNO;
648 			break;
649 		case LINE_APPEND:
650 			break;
651 		}
652 
653 	if (ep->c_nlines != OOBLNO)
654 		switch (op) {
655 		case LINE_INSERT:
656 			++ep->c_nlines;
657 			break;
658 		case LINE_DELETE:
659 			--ep->c_nlines;
660 			break;
661 		case LINE_APPEND:
662 		case LINE_RESET:
663 			break;
664 		}
665 }
666 
667 /*
668  * PUBLIC: int db_msg_open __P((SCR *, const char *, DB **));
669  */
db_msg_open(SCR * sp,const char * file,DB ** dbp)670 int db_msg_open(SCR *sp, const char *file, DB **dbp)
671 {
672 	*dbp = dbopen(file, O_NONBLOCK | O_RDONLY, 0, DB_RECNO, NULL);
673 
674 	return *dbp == NULL;
675 }
676 
677 /*
678  * PUBLIC: int db_init __P((SCR *, EXF *, char *, char *, size_t, int *));
679  */
680 int
db_init(SCR * sp,EXF * ep,char * rcv_name,char * oname,size_t psize,int * open_err)681 db_init(SCR *sp, EXF *ep, char *rcv_name, char *oname, size_t psize, int *open_err)
682 {
683 	RECNOINFO oinfo;
684 
685 	memset(&oinfo, 0, sizeof(RECNOINFO));
686 	oinfo.bval = '\n';			/* Always set. */
687 	/*
688 	 * If we are not recovering, set the pagesize and arrange to
689 	 * first get a snapshot of the file.
690 	 */
691 	if (rcv_name == NULL) {
692 		oinfo.psize = psize;
693 		oinfo.flags = R_SNAPSHOT;
694 	}
695 	/*
696 	 * Always set the btree name, otherwise we are going to be using
697 	 * an in-memory database for the btree.
698 	 */
699 	oinfo.bfname = ep->rcv_path;
700 
701 #define _DB_OPEN_MODE	S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH
702 
703 	ep->db = dbopen(rcv_name == NULL ? oname : NULL,
704 	    O_NONBLOCK | O_RDONLY, _DB_OPEN_MODE, DB_RECNO, &oinfo);
705 
706 	if (!ep->db) {
707 		msgq_str(sp,
708 		    M_DBERR, rcv_name == NULL ? oname : rcv_name, "%s");
709 		/*
710 		 * !!!
711 		 * Historically, vi permitted users to edit files that couldn't
712 		 * be read.  This isn't useful for single files from a command
713 		 * line, but it's quite useful for "vi *.c", since you can skip
714 		 * past files that you can't read.
715 		 */
716 		ep->db = NULL; /* Don't close it; it wasn't opened */
717 
718 		*open_err = 1;
719 		return 1;
720 	} else {
721 		/*
722 		 * We always sync the underlying btree so that the header
723 		 * is written first
724 		 */
725 		ep->db->sync(ep->db, R_RECNOSYNC);
726 	}
727 
728 	return 0;
729 }
730 
731 const char *
db_strerror(int error)732 db_strerror(int error)
733 {
734 	return error > 0 ? strerror(error) : "record not found";
735 }
736