xref: /netbsd-src/lib/libedit/read.c (revision 3816d47b2c42fcd6e549e3407f842a5b1a1d23ad)
1 /*	$NetBSD: read.c,v 1.54 2009/12/31 15:58:26 christos Exp $	*/
2 
3 /*-
4  * Copyright (c) 1992, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Christos Zoulas of Cornell University.
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 #include "config.h"
36 #if !defined(lint) && !defined(SCCSID)
37 #if 0
38 static char sccsid[] = "@(#)read.c	8.1 (Berkeley) 6/4/93";
39 #else
40 __RCSID("$NetBSD: read.c,v 1.54 2009/12/31 15:58:26 christos Exp $");
41 #endif
42 #endif /* not lint && not SCCSID */
43 
44 /*
45  * read.c: Clean this junk up! This is horrible code.
46  *	   Terminal read functions
47  */
48 #include <errno.h>
49 #include <fcntl.h>
50 #include <unistd.h>
51 #include <stdlib.h>
52 #include <limits.h>
53 #include "el.h"
54 
55 #define	OKCMD	-1	/* must be -1! */
56 
57 private int	read__fixio(int, int);
58 private int	read_preread(EditLine *);
59 private int	read_char(EditLine *, Char *);
60 private int	read_getcmd(EditLine *, el_action_t *, Char *);
61 private void	read_pop(c_macro_t *);
62 
63 /* read_init():
64  *	Initialize the read stuff
65  */
66 protected int
67 read_init(EditLine *el)
68 {
69 	/* builtin read_char */
70 	el->el_read.read_char = read_char;
71 	return 0;
72 }
73 
74 
75 /* el_read_setfn():
76  *	Set the read char function to the one provided.
77  *	If it is set to EL_BUILTIN_GETCFN, then reset to the builtin one.
78  */
79 protected int
80 el_read_setfn(EditLine *el, el_rfunc_t rc)
81 {
82 	el->el_read.read_char = (rc == EL_BUILTIN_GETCFN) ? read_char : rc;
83 	return 0;
84 }
85 
86 
87 /* el_read_getfn():
88  *	return the current read char function, or EL_BUILTIN_GETCFN
89  *	if it is the default one
90  */
91 protected el_rfunc_t
92 el_read_getfn(EditLine *el)
93 {
94        return (el->el_read.read_char == read_char) ?
95 	    EL_BUILTIN_GETCFN : el->el_read.read_char;
96 }
97 
98 
99 #ifndef MIN
100 #define MIN(A,B) ((A) < (B) ? (A) : (B))
101 #endif
102 
103 #ifdef DEBUG_EDIT
104 private void
105 read_debug(EditLine *el)
106 {
107 
108 	if (el->el_line.cursor > el->el_line.lastchar)
109 		(void) fprintf(el->el_errfile, "cursor > lastchar\r\n");
110 	if (el->el_line.cursor < el->el_line.buffer)
111 		(void) fprintf(el->el_errfile, "cursor < buffer\r\n");
112 	if (el->el_line.cursor > el->el_line.limit)
113 		(void) fprintf(el->el_errfile, "cursor > limit\r\n");
114 	if (el->el_line.lastchar > el->el_line.limit)
115 		(void) fprintf(el->el_errfile, "lastchar > limit\r\n");
116 	if (el->el_line.limit != &el->el_line.buffer[EL_BUFSIZ - 2])
117 		(void) fprintf(el->el_errfile, "limit != &buffer[EL_BUFSIZ-2]\r\n");
118 }
119 #endif /* DEBUG_EDIT */
120 
121 
122 /* read__fixio():
123  *	Try to recover from a read error
124  */
125 /* ARGSUSED */
126 private int
127 read__fixio(int fd __attribute__((__unused__)), int e)
128 {
129 
130 	switch (e) {
131 	case -1:		/* Make sure that the code is reachable */
132 
133 #ifdef EWOULDBLOCK
134 	case EWOULDBLOCK:
135 #ifndef TRY_AGAIN
136 #define	TRY_AGAIN
137 #endif
138 #endif /* EWOULDBLOCK */
139 
140 #if defined(POSIX) && defined(EAGAIN)
141 #if defined(EWOULDBLOCK) && EWOULDBLOCK != EAGAIN
142 	case EAGAIN:
143 #ifndef TRY_AGAIN
144 #define	TRY_AGAIN
145 #endif
146 #endif /* EWOULDBLOCK && EWOULDBLOCK != EAGAIN */
147 #endif /* POSIX && EAGAIN */
148 
149 		e = 0;
150 #ifdef TRY_AGAIN
151 #if defined(F_SETFL) && defined(O_NDELAY)
152 		if ((e = fcntl(fd, F_GETFL, 0)) == -1)
153 			return (-1);
154 
155 		if (fcntl(fd, F_SETFL, e & ~O_NDELAY) == -1)
156 			return (-1);
157 		else
158 			e = 1;
159 #endif /* F_SETFL && O_NDELAY */
160 
161 #ifdef FIONBIO
162 		{
163 			int zero = 0;
164 
165 			if (ioctl(fd, FIONBIO, (ioctl_t) & zero) == -1)
166 				return (-1);
167 			else
168 				e = 1;
169 		}
170 #endif /* FIONBIO */
171 
172 #endif /* TRY_AGAIN */
173 		return (e ? 0 : -1);
174 
175 	case EINTR:
176 		return (-1);
177 
178 	default:
179 		return (-1);
180 	}
181 }
182 
183 
184 /* read_preread():
185  *	Try to read the stuff in the input queue;
186  */
187 private int
188 read_preread(EditLine *el)
189 {
190 	int chrs = 0;
191 
192 	if (el->el_tty.t_mode == ED_IO)
193 		return (0);
194 
195 #ifndef WIDECHAR
196 /* FIONREAD attempts to buffer up multiple bytes, and to make that work
197  * properly with partial wide/UTF-8 characters would need some careful work. */
198 #ifdef FIONREAD
199 	(void) ioctl(el->el_infd, FIONREAD, (ioctl_t) & chrs);
200 	if (chrs > 0) {
201 		char buf[EL_BUFSIZ];
202 
203 		chrs = read(el->el_infd, buf,
204 		    (size_t) MIN(chrs, EL_BUFSIZ - 1));
205 		if (chrs > 0) {
206 			buf[chrs] = '\0';
207 			el_push(el, buf);
208 		}
209 	}
210 #endif /* FIONREAD */
211 #endif
212 	return (chrs > 0);
213 }
214 
215 
216 /* el_push():
217  *	Push a macro
218  */
219 public void
220 FUN(el,push)(EditLine *el, const Char *str)
221 {
222 	c_macro_t *ma = &el->el_chared.c_macro;
223 
224 	if (str != NULL && ma->level + 1 < EL_MAXMACRO) {
225 		ma->level++;
226 		if ((ma->macro[ma->level] = Strdup(str)) != NULL)
227 			return;
228 		ma->level--;
229 	}
230 	term_beep(el);
231 	term__flush(el);
232 }
233 
234 
235 /* read_getcmd():
236  *	Return next command from the input stream.
237  *	Character values > 255 are not looked up in the map, but inserted.
238  */
239 private int
240 read_getcmd(EditLine *el, el_action_t *cmdnum, Char *ch)
241 {
242 	el_action_t cmd;
243 	int num;
244 
245 	el->el_errno = 0;
246 	do {
247 		if ((num = FUN(el,getc)(el, ch)) != 1) {/* if EOF or error */
248 			el->el_errno = num == 0 ? 0 : errno;
249 			return (num);
250 		}
251 
252 #ifdef	KANJI
253 		if ((*ch & 0200)) {
254 			el->el_state.metanext = 0;
255 			cmd = CcViMap[' '];
256 			break;
257 		} else
258 #endif /* KANJI */
259 
260 		if (el->el_state.metanext) {
261 			el->el_state.metanext = 0;
262 			*ch |= 0200;
263 		}
264 #ifdef WIDECHAR
265                 if (*ch >= N_KEYS)
266                         cmd = ED_INSERT;
267 		else
268 #endif
269                         cmd = el->el_map.current[(unsigned char) *ch];
270 		if (cmd == ED_SEQUENCE_LEAD_IN) {
271 			key_value_t val;
272 			switch (key_get(el, ch, &val)) {
273 			case XK_CMD:
274 				cmd = val.cmd;
275 				break;
276 			case XK_STR:
277 				FUN(el,push)(el, val.str);
278 				break;
279 #ifdef notyet
280 			case XK_EXE:
281 				/* XXX: In the future to run a user function */
282 				RunCommand(val.str);
283 				break;
284 #endif
285 			default:
286 				EL_ABORT((el->el_errfile, "Bad XK_ type \n"));
287 				break;
288 			}
289 		}
290 		if (el->el_map.alt == NULL)
291 			el->el_map.current = el->el_map.key;
292 	} while (cmd == ED_SEQUENCE_LEAD_IN);
293 	*cmdnum = cmd;
294 	return (OKCMD);
295 }
296 
297 #ifdef WIDECHAR
298 /* utf8_islead():
299  *      Test whether a byte is a leading byte of a UTF-8 sequence.
300  */
301 private int
302 utf8_islead(unsigned char c)
303 {
304         return (c < 0x80) ||             /* single byte char */
305                (c >= 0xc2 && c <= 0xf4); /* start of multibyte sequence */
306 }
307 #endif
308 
309 /* read_char():
310  *	Read a character from the tty.
311  */
312 private int
313 read_char(EditLine *el, Char *cp)
314 {
315 	ssize_t num_read;
316 	int tried = 0;
317         char cbuf[MB_LEN_MAX];
318         int cbp = 0;
319         int bytes = 0;
320 
321  again:
322 	el->el_signal->sig_no = 0;
323 	while ((num_read = read(el->el_infd, cbuf + cbp, 1)) == -1) {
324 		if (el->el_signal->sig_no == SIGCONT) {
325 			sig_set(el);
326 			el_set(el, EL_REFRESH);
327 			goto again;
328 		}
329 		if (!tried && read__fixio(el->el_infd, errno) == 0)
330 			tried = 1;
331 		else {
332 			*cp = '\0';
333 			return (-1);
334 		}
335 	}
336 
337 #ifdef WIDECHAR
338 	if (el->el_flags & CHARSET_IS_UTF8) {
339 		if (!utf8_islead((unsigned char)cbuf[0]))
340 			goto again; /* discard the byte we read and try again */
341 		++cbp;
342 		if ((bytes = ct_mbtowc(cp, cbuf, cbp)) == -1) {
343 			ct_mbtowc_reset;
344 			if (cbp >= MB_LEN_MAX) { /* "shouldn't happen" */
345 				*cp = '\0';
346 				return (-1);
347 			}
348 			goto again;
349 		}
350 	} else  /* we don't support other multibyte charsets */
351 #endif
352 		*cp = (unsigned char)cbuf[0];
353 
354 	if ((el->el_flags & IGNORE_EXTCHARS) && bytes > 1) {
355 		cbp = 0; /* skip this character */
356 		goto again;
357 	}
358 
359 	return (int)num_read;
360 }
361 
362 /* read_pop():
363  *	Pop a macro from the stack
364  */
365 private void
366 read_pop(c_macro_t *ma)
367 {
368 	int i;
369 
370 	el_free(ma->macro[0]);
371 	for (i = 0; i < ma->level; i++)
372 		ma->macro[i] = ma->macro[i + 1];
373 	ma->level--;
374 	ma->offset = 0;
375 }
376 
377 /* el_getc():
378  *	Read a character
379  */
380 public int
381 FUN(el,getc)(EditLine *el, Char *cp)
382 {
383 	int num_read;
384 	c_macro_t *ma = &el->el_chared.c_macro;
385 
386 	term__flush(el);
387 	for (;;) {
388 		if (ma->level < 0) {
389 			if (!read_preread(el))
390 				break;
391 		}
392 
393 		if (ma->level < 0)
394 			break;
395 
396 		if (ma->macro[0][ma->offset] == '\0') {
397 			read_pop(ma);
398 			continue;
399 		}
400 
401 		*cp = ma->macro[0][ma->offset++];
402 
403 		if (ma->macro[0][ma->offset] == '\0') {
404 			/* Needed for QuoteMode On */
405 			read_pop(ma);
406 		}
407 
408 		return (1);
409 	}
410 
411 #ifdef DEBUG_READ
412 	(void) fprintf(el->el_errfile, "Turning raw mode on\n");
413 #endif /* DEBUG_READ */
414 	if (tty_rawmode(el) < 0)/* make sure the tty is set up correctly */
415 		return (0);
416 
417 #ifdef DEBUG_READ
418 	(void) fprintf(el->el_errfile, "Reading a character\n");
419 #endif /* DEBUG_READ */
420 	num_read = (*el->el_read.read_char)(el, cp);
421 #ifdef WIDECHAR
422 	if (el->el_flags & NARROW_READ)
423 		*cp = *(char *)(void *)cp;
424 #endif
425 #ifdef DEBUG_READ
426 	(void) fprintf(el->el_errfile, "Got it %c\n", *cp);
427 #endif /* DEBUG_READ */
428 	return (num_read);
429 }
430 
431 protected void
432 read_prepare(EditLine *el)
433 {
434 	if (el->el_flags & HANDLE_SIGNALS)
435 		sig_set(el);
436 	if (el->el_flags & NO_TTY)
437 		return;
438 	if ((el->el_flags & (UNBUFFERED|EDIT_DISABLED)) == UNBUFFERED)
439 		tty_rawmode(el);
440 
441 	/* This is relatively cheap, and things go terribly wrong if
442 	   we have the wrong size. */
443 	el_resize(el);
444 	re_clear_display(el);	/* reset the display stuff */
445 	ch_reset(el, 0);
446 	re_refresh(el);		/* print the prompt */
447 
448 	if (el->el_flags & UNBUFFERED)
449 		term__flush(el);
450 }
451 
452 protected void
453 read_finish(EditLine *el)
454 {
455 	if ((el->el_flags & UNBUFFERED) == 0)
456 		(void) tty_cookedmode(el);
457 	if (el->el_flags & HANDLE_SIGNALS)
458 		sig_clr(el);
459 }
460 
461 public const Char *
462 FUN(el,gets)(EditLine *el, int *nread)
463 {
464 	int retval;
465 	el_action_t cmdnum = 0;
466 	int num;		/* how many chars we have read at NL */
467 	Char ch;
468 	int crlf = 0;
469 	int nrb;
470 #ifdef FIONREAD
471 	c_macro_t *ma = &el->el_chared.c_macro;
472 #endif /* FIONREAD */
473 
474 	if (nread == NULL)
475 		nread = &nrb;
476 	*nread = 0;
477 
478 	if (el->el_flags & NO_TTY) {
479 		Char *cp = el->el_line.buffer;
480 		size_t idx;
481 
482 		while ((num = (*el->el_read.read_char)(el, cp)) == 1) {
483 			/* make sure there is space for next character */
484 			if (cp + 1 >= el->el_line.limit) {
485 				idx = (cp - el->el_line.buffer);
486 				if (!ch_enlargebufs(el, 2))
487 					break;
488 				cp = &el->el_line.buffer[idx];
489 			}
490 			cp++;
491 			if (el->el_flags & UNBUFFERED)
492 				break;
493 			if (cp[-1] == '\r' || cp[-1] == '\n')
494 				break;
495 		}
496 		if (num == -1) {
497 			if (errno == EINTR)
498 				cp = el->el_line.buffer;
499 			el->el_errno = errno;
500 		}
501 
502 		el->el_line.cursor = el->el_line.lastchar = cp;
503 		*cp = '\0';
504 		*nread = (int)(el->el_line.cursor - el->el_line.buffer);
505 		goto done;
506 	}
507 
508 
509 #ifdef FIONREAD
510 	if (el->el_tty.t_mode == EX_IO && ma->level < 0) {
511 		long chrs = 0;
512 
513 		(void) ioctl(el->el_infd, FIONREAD, (ioctl_t) & chrs);
514 		if (chrs == 0) {
515 			if (tty_rawmode(el) < 0) {
516 				errno = 0;
517 				*nread = 0;
518 				return (NULL);
519 			}
520 		}
521 	}
522 #endif /* FIONREAD */
523 
524 	if ((el->el_flags & UNBUFFERED) == 0)
525 		read_prepare(el);
526 
527 	if (el->el_flags & EDIT_DISABLED) {
528 		Char *cp;
529 		size_t idx;
530 
531 		if ((el->el_flags & UNBUFFERED) == 0)
532 			cp = el->el_line.buffer;
533 		else
534 			cp = el->el_line.lastchar;
535 
536 		term__flush(el);
537 
538 		while ((num = (*el->el_read.read_char)(el, cp)) == 1) {
539 			/* make sure there is space next character */
540 			if (cp + 1 >= el->el_line.limit) {
541 				idx = (cp - el->el_line.buffer);
542 				if (!ch_enlargebufs(el, 2))
543 					break;
544 				cp = &el->el_line.buffer[idx];
545 			}
546 			cp++;
547 			crlf = cp[-1] == '\r' || cp[-1] == '\n';
548 			if (el->el_flags & UNBUFFERED)
549 				break;
550 			if (crlf)
551 				break;
552 		}
553 
554 		if (num == -1) {
555 			if (errno == EINTR)
556 				cp = el->el_line.buffer;
557 			el->el_errno = errno;
558 		}
559 
560 		el->el_line.cursor = el->el_line.lastchar = cp;
561 		*cp = '\0';
562 		goto done;
563 	}
564 
565 	for (num = OKCMD; num == OKCMD;) {	/* while still editing this
566 						 * line */
567 #ifdef DEBUG_EDIT
568 		read_debug(el);
569 #endif /* DEBUG_EDIT */
570 		/* if EOF or error */
571 		if ((num = read_getcmd(el, &cmdnum, &ch)) != OKCMD) {
572 #ifdef DEBUG_READ
573 			(void) fprintf(el->el_errfile,
574 			    "Returning from el_gets %d\n", num);
575 #endif /* DEBUG_READ */
576 			break;
577 		}
578 		if (el->el_errno == EINTR) {
579 			el->el_line.buffer[0] = '\0';
580 			el->el_line.lastchar =
581 			    el->el_line.cursor = el->el_line.buffer;
582 			break;
583 		}
584 		if ((unsigned int)cmdnum >= (unsigned int)el->el_map.nfunc) {	/* BUG CHECK command */
585 #ifdef DEBUG_EDIT
586 			(void) fprintf(el->el_errfile,
587 			    "ERROR: illegal command from key 0%o\r\n", ch);
588 #endif /* DEBUG_EDIT */
589 			continue;	/* try again */
590 		}
591 		/* now do the real command */
592 #ifdef DEBUG_READ
593 		{
594 			el_bindings_t *b;
595 			for (b = el->el_map.help; b->name; b++)
596 				if (b->func == cmdnum)
597 					break;
598 			if (b->name)
599 				(void) fprintf(el->el_errfile,
600 				    "Executing %s\n", b->name);
601 			else
602 				(void) fprintf(el->el_errfile,
603 				    "Error command = %d\n", cmdnum);
604 		}
605 #endif /* DEBUG_READ */
606 		/* vi redo needs these way down the levels... */
607 		el->el_state.thiscmd = cmdnum;
608 		el->el_state.thisch = ch;
609 		if (el->el_map.type == MAP_VI &&
610 		    el->el_map.current == el->el_map.key &&
611 		    el->el_chared.c_redo.pos < el->el_chared.c_redo.lim) {
612 			if (cmdnum == VI_DELETE_PREV_CHAR &&
613 			    el->el_chared.c_redo.pos != el->el_chared.c_redo.buf
614 			    && Isprint(el->el_chared.c_redo.pos[-1]))
615 				el->el_chared.c_redo.pos--;
616 			else
617 				*el->el_chared.c_redo.pos++ = ch;
618 		}
619 		retval = (*el->el_map.func[cmdnum]) (el, ch);
620 #ifdef DEBUG_READ
621 		(void) fprintf(el->el_errfile,
622 			"Returned state %d\n", retval );
623 #endif /* DEBUG_READ */
624 
625 		/* save the last command here */
626 		el->el_state.lastcmd = cmdnum;
627 
628 		/* use any return value */
629 		switch (retval) {
630 		case CC_CURSOR:
631 			re_refresh_cursor(el);
632 			break;
633 
634 		case CC_REDISPLAY:
635 			re_clear_lines(el);
636 			re_clear_display(el);
637 			/* FALLTHROUGH */
638 
639 		case CC_REFRESH:
640 			re_refresh(el);
641 			break;
642 
643 		case CC_REFRESH_BEEP:
644 			re_refresh(el);
645 			term_beep(el);
646 			break;
647 
648 		case CC_NORM:	/* normal char */
649 			break;
650 
651 		case CC_ARGHACK:	/* Suggested by Rich Salz */
652 			/* <rsalz@pineapple.bbn.com> */
653 			continue;	/* keep going... */
654 
655 		case CC_EOF:	/* end of file typed */
656 			if ((el->el_flags & UNBUFFERED) == 0)
657 				num = 0;
658 			else if (num == -1) {
659 				*el->el_line.lastchar++ = CONTROL('d');
660 				el->el_line.cursor = el->el_line.lastchar;
661 				num = 1;
662 			}
663 			break;
664 
665 		case CC_NEWLINE:	/* normal end of line */
666 			num = (int)(el->el_line.lastchar - el->el_line.buffer);
667 			break;
668 
669 		case CC_FATAL:	/* fatal error, reset to known state */
670 #ifdef DEBUG_READ
671 			(void) fprintf(el->el_errfile,
672 			    "*** editor fatal ERROR ***\r\n\n");
673 #endif /* DEBUG_READ */
674 			/* put (real) cursor in a known place */
675 			re_clear_display(el);	/* reset the display stuff */
676 			ch_reset(el, 1);	/* reset the input pointers */
677 			re_refresh(el);	/* print the prompt again */
678 			break;
679 
680 		case CC_ERROR:
681 		default:	/* functions we don't know about */
682 #ifdef DEBUG_READ
683 			(void) fprintf(el->el_errfile,
684 			    "*** editor ERROR ***\r\n\n");
685 #endif /* DEBUG_READ */
686 			term_beep(el);
687 			term__flush(el);
688 			break;
689 		}
690 		el->el_state.argument = 1;
691 		el->el_state.doingarg = 0;
692 		el->el_chared.c_vcmd.action = NOP;
693 		if (el->el_flags & UNBUFFERED)
694 			break;
695 	}
696 
697 	term__flush(el);		/* flush any buffered output */
698 	/* make sure the tty is set up correctly */
699 	if ((el->el_flags & UNBUFFERED) == 0) {
700 		read_finish(el);
701 		*nread = num != -1 ? num : 0;
702 	} else {
703 		*nread = (int)(el->el_line.lastchar - el->el_line.buffer);
704 	}
705 done:
706 	if (*nread == 0) {
707 		if (num == -1) {
708 			*nread = -1;
709 			errno = el->el_errno;
710 		}
711 		return NULL;
712 	} else
713 		return el->el_line.buffer;
714 }
715