Update libedit from version 2012-03-11 to 2012-12-13 on vendor branch
[dragonfly.git] / contrib / libedit / src / read.c
1 /*      $NetBSD: read.c,v 1.69 2012/09/11 12:31:08 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 1.69 2012/09/11 12:31:08 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, &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 0;
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, &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         terminal_beep(el);
231         terminal__flush(el);
232 }
233
234
235 /* read_getcmd():
236  *      Get next command from the input stream, return OKCMD on success.
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 0;       /* not OKCMD */
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                         keymacro_value_t val;
272                         switch (keymacro_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(int 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         size_t 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, (size_t)1)) == -1) {
324                 int e = errno;
325                 switch (el->el_signal->sig_no) {
326                 case SIGCONT:
327                         FUN(el,set)(el, EL_REFRESH);
328                         /*FALLTHROUGH*/
329                 case SIGWINCH:
330                         sig_set(el);
331                         goto again;
332                 default:
333                         break;
334                 }
335                 if (!tried && read__fixio(el->el_infd, e) == 0)
336                         tried = 1;
337                 else {
338                         errno = e;
339                         *cp = '\0';
340                         return -1;
341                 }
342         }
343
344 #ifdef WIDECHAR
345         if (el->el_flags & CHARSET_IS_UTF8) {
346                 if (!utf8_islead((unsigned char)cbuf[0]))
347                         goto again; /* discard the byte we read and try again */
348                 ++cbp;
349                 if ((bytes = ct_mbtowc(cp, cbuf, cbp)) == -1) {
350                         ct_mbtowc_reset;
351                         if (cbp >= MB_LEN_MAX) { /* "shouldn't happen" */
352                                 errno = EILSEQ;
353                                 *cp = '\0';
354                                 return -1;
355                         }
356                         goto again;
357                 }
358         } else if (isascii((unsigned char)cbuf[0]) ||
359                 /* we don't support other multibyte charsets */
360                 ++cbp != 1 ||
361                 /* Try non-ASCII characters in a 8-bit character set */
362                 (bytes = ct_mbtowc(cp, cbuf, cbp)) != 1)
363 #endif
364                 *cp = (unsigned char)cbuf[0];
365
366         if ((el->el_flags & IGNORE_EXTCHARS) && bytes > 1) {
367                 cbp = 0; /* skip this character */
368                 goto again;
369         }
370
371         return (int)num_read;
372 }
373
374 /* read_pop():
375  *      Pop a macro from the stack
376  */
377 private void
378 read_pop(c_macro_t *ma)
379 {
380         int i;
381
382         el_free(ma->macro[0]);
383         for (i = 0; i < ma->level; i++)
384                 ma->macro[i] = ma->macro[i + 1];
385         ma->level--;
386         ma->offset = 0;
387 }
388
389 /* el_getc():
390  *      Read a character
391  */
392 public int
393 FUN(el,getc)(EditLine *el, Char *cp)
394 {
395         int num_read;
396         c_macro_t *ma = &el->el_chared.c_macro;
397
398         terminal__flush(el);
399         for (;;) {
400                 if (ma->level < 0) {
401                         if (!read_preread(el))
402                                 break;
403                 }
404
405                 if (ma->level < 0)
406                         break;
407
408                 if (ma->macro[0][ma->offset] == '\0') {
409                         read_pop(ma);
410                         continue;
411                 }
412
413                 *cp = ma->macro[0][ma->offset++];
414
415                 if (ma->macro[0][ma->offset] == '\0') {
416                         /* Needed for QuoteMode On */
417                         read_pop(ma);
418                 }
419
420                 return 1;
421         }
422
423 #ifdef DEBUG_READ
424         (void) fprintf(el->el_errfile, "Turning raw mode on\n");
425 #endif /* DEBUG_READ */
426         if (tty_rawmode(el) < 0)/* make sure the tty is set up correctly */
427                 return 0;
428
429 #ifdef DEBUG_READ
430         (void) fprintf(el->el_errfile, "Reading a character\n");
431 #endif /* DEBUG_READ */
432         num_read = (*el->el_read.read_char)(el, cp);
433         if (num_read < 0)
434                 el->el_errno = errno;
435 #ifdef WIDECHAR
436         if (el->el_flags & NARROW_READ)
437                 *cp = *(char *)(void *)cp;
438 #endif
439 #ifdef DEBUG_READ
440         (void) fprintf(el->el_errfile, "Got it %c\n", *cp);
441 #endif /* DEBUG_READ */
442         return num_read;
443 }
444
445 protected void
446 read_prepare(EditLine *el)
447 {
448         if (el->el_flags & HANDLE_SIGNALS)
449                 sig_set(el);
450         if (el->el_flags & NO_TTY)
451                 return;
452         if ((el->el_flags & (UNBUFFERED|EDIT_DISABLED)) == UNBUFFERED)
453                 tty_rawmode(el);
454
455         /* This is relatively cheap, and things go terribly wrong if
456            we have the wrong size. */
457         el_resize(el);
458         re_clear_display(el);   /* reset the display stuff */
459         ch_reset(el, 0);
460         re_refresh(el);         /* print the prompt */
461
462         if (el->el_flags & UNBUFFERED)
463                 terminal__flush(el);
464 }
465
466 protected void
467 read_finish(EditLine *el)
468 {
469         if ((el->el_flags & UNBUFFERED) == 0)
470                 (void) tty_cookedmode(el);
471         if (el->el_flags & HANDLE_SIGNALS)
472                 sig_clr(el);
473 }
474
475 public const Char *
476 FUN(el,gets)(EditLine *el, int *nread)
477 {
478         int retval;
479         el_action_t cmdnum = 0;
480         int num;                /* how many chars we have read at NL */
481         Char ch, *cp;
482         int crlf = 0;
483         int nrb;
484 #ifdef FIONREAD
485         c_macro_t *ma = &el->el_chared.c_macro;
486 #endif /* FIONREAD */
487
488         if (nread == NULL)
489                 nread = &nrb;
490         *nread = 0;
491
492         if (el->el_flags & NO_TTY) {
493                 size_t idx;
494
495                 cp = el->el_line.buffer;
496                 while ((num = (*el->el_read.read_char)(el, cp)) == 1) {
497                         /* make sure there is space for next character */
498                         if (cp + 1 >= el->el_line.limit) {
499                                 idx = (size_t)(cp - el->el_line.buffer);
500                                 if (!ch_enlargebufs(el, (size_t)2))
501                                         break;
502                                 cp = &el->el_line.buffer[idx];
503                         }
504                         cp++;
505                         if (el->el_flags & UNBUFFERED)
506                                 break;
507                         if (cp[-1] == '\r' || cp[-1] == '\n')
508                                 break;
509                 }
510                 if (num == -1) {
511                         if (errno == EINTR)
512                                 cp = el->el_line.buffer;
513                         el->el_errno = errno;
514                 }
515
516                 goto noedit;
517         }
518
519
520 #ifdef FIONREAD
521         if (el->el_tty.t_mode == EX_IO && ma->level < 0) {
522                 long chrs = 0;
523
524                 (void) ioctl(el->el_infd, FIONREAD, &chrs);
525                 if (chrs == 0) {
526                         if (tty_rawmode(el) < 0) {
527                                 errno = 0;
528                                 *nread = 0;
529                                 return NULL;
530                         }
531                 }
532         }
533 #endif /* FIONREAD */
534
535         if ((el->el_flags & UNBUFFERED) == 0)
536                 read_prepare(el);
537
538         if (el->el_flags & EDIT_DISABLED) {
539                 size_t idx;
540
541                 if ((el->el_flags & UNBUFFERED) == 0)
542                         cp = el->el_line.buffer;
543                 else
544                         cp = el->el_line.lastchar;
545
546                 terminal__flush(el);
547
548                 while ((num = (*el->el_read.read_char)(el, cp)) == 1) {
549                         /* make sure there is space next character */
550                         if (cp + 1 >= el->el_line.limit) {
551                                 idx = (size_t)(cp - el->el_line.buffer);
552                                 if (!ch_enlargebufs(el, (size_t)2))
553                                         break;
554                                 cp = &el->el_line.buffer[idx];
555                         }
556                         cp++;
557                         crlf = cp[-1] == '\r' || cp[-1] == '\n';
558                         if (el->el_flags & UNBUFFERED)
559                                 break;
560                         if (crlf)
561                                 break;
562                 }
563
564                 if (num == -1) {
565                         if (errno == EINTR)
566                                 cp = el->el_line.buffer;
567                         el->el_errno = errno;
568                 }
569
570                 goto noedit;
571         }
572
573         for (num = OKCMD; num == OKCMD;) {      /* while still editing this
574                                                  * line */
575 #ifdef DEBUG_EDIT
576                 read_debug(el);
577 #endif /* DEBUG_EDIT */
578                 /* if EOF or error */
579                 if ((num = read_getcmd(el, &cmdnum, &ch)) != OKCMD) {
580                         num = -1;
581 #ifdef DEBUG_READ
582                         (void) fprintf(el->el_errfile,
583                             "Returning from el_gets %d\n", num);
584 #endif /* DEBUG_READ */
585                         break;
586                 }
587                 if (el->el_errno == EINTR) {
588                         el->el_line.buffer[0] = '\0';
589                         el->el_line.lastchar =
590                             el->el_line.cursor = el->el_line.buffer;
591                         break;
592                 }
593                 if ((unsigned int)cmdnum >= (unsigned int)el->el_map.nfunc) {   /* BUG CHECK command */
594 #ifdef DEBUG_EDIT
595                         (void) fprintf(el->el_errfile,
596                             "ERROR: illegal command from key 0%o\r\n", ch);
597 #endif /* DEBUG_EDIT */
598                         continue;       /* try again */
599                 }
600                 /* now do the real command */
601 #ifdef DEBUG_READ
602                 {
603                         el_bindings_t *b;
604                         for (b = el->el_map.help; b->name; b++)
605                                 if (b->func == cmdnum)
606                                         break;
607                         if (b->name)
608                                 (void) fprintf(el->el_errfile,
609                                     "Executing %s\n", b->name);
610                         else
611                                 (void) fprintf(el->el_errfile,
612                                     "Error command = %d\n", cmdnum);
613                 }
614 #endif /* DEBUG_READ */
615                 /* vi redo needs these way down the levels... */
616                 el->el_state.thiscmd = cmdnum;
617                 el->el_state.thisch = ch;
618                 if (el->el_map.type == MAP_VI &&
619                     el->el_map.current == el->el_map.key &&
620                     el->el_chared.c_redo.pos < el->el_chared.c_redo.lim) {
621                         if (cmdnum == VI_DELETE_PREV_CHAR &&
622                             el->el_chared.c_redo.pos != el->el_chared.c_redo.buf
623                             && Isprint(el->el_chared.c_redo.pos[-1]))
624                                 el->el_chared.c_redo.pos--;
625                         else
626                                 *el->el_chared.c_redo.pos++ = ch;
627                 }
628                 retval = (*el->el_map.func[cmdnum]) (el, ch);
629 #ifdef DEBUG_READ
630                 (void) fprintf(el->el_errfile,
631                         "Returned state %d\n", retval );
632 #endif /* DEBUG_READ */
633
634                 /* save the last command here */
635                 el->el_state.lastcmd = cmdnum;
636
637                 /* use any return value */
638                 switch (retval) {
639                 case CC_CURSOR:
640                         re_refresh_cursor(el);
641                         break;
642
643                 case CC_REDISPLAY:
644                         re_clear_lines(el);
645                         re_clear_display(el);
646                         /* FALLTHROUGH */
647
648                 case CC_REFRESH:
649                         re_refresh(el);
650                         break;
651
652                 case CC_REFRESH_BEEP:
653                         re_refresh(el);
654                         terminal_beep(el);
655                         break;
656
657                 case CC_NORM:   /* normal char */
658                         break;
659
660                 case CC_ARGHACK:        /* Suggested by Rich Salz */
661                         /* <rsalz@pineapple.bbn.com> */
662                         continue;       /* keep going... */
663
664                 case CC_EOF:    /* end of file typed */
665                         if ((el->el_flags & UNBUFFERED) == 0)
666                                 num = 0;
667                         else if (num == -1) {
668                                 *el->el_line.lastchar++ = CONTROL('d');
669                                 el->el_line.cursor = el->el_line.lastchar;
670                                 num = 1;
671                         }
672                         break;
673
674                 case CC_NEWLINE:        /* normal end of line */
675                         num = (int)(el->el_line.lastchar - el->el_line.buffer);
676                         break;
677
678                 case CC_FATAL:  /* fatal error, reset to known state */
679 #ifdef DEBUG_READ
680                         (void) fprintf(el->el_errfile,
681                             "*** editor fatal ERROR ***\r\n\n");
682 #endif /* DEBUG_READ */
683                         /* put (real) cursor in a known place */
684                         re_clear_display(el);   /* reset the display stuff */
685                         ch_reset(el, 1);        /* reset the input pointers */
686                         re_refresh(el); /* print the prompt again */
687                         break;
688
689                 case CC_ERROR:
690                 default:        /* functions we don't know about */
691 #ifdef DEBUG_READ
692                         (void) fprintf(el->el_errfile,
693                             "*** editor ERROR ***\r\n\n");
694 #endif /* DEBUG_READ */
695                         terminal_beep(el);
696                         terminal__flush(el);
697                         break;
698                 }
699                 el->el_state.argument = 1;
700                 el->el_state.doingarg = 0;
701                 el->el_chared.c_vcmd.action = NOP;
702                 if (el->el_flags & UNBUFFERED)
703                         break;
704         }
705
706         terminal__flush(el);            /* flush any buffered output */
707         /* make sure the tty is set up correctly */
708         if ((el->el_flags & UNBUFFERED) == 0) {
709                 read_finish(el);
710                 *nread = num != -1 ? num : 0;
711         } else {
712                 *nread = (int)(el->el_line.lastchar - el->el_line.buffer);
713         }
714         goto done;
715 noedit:
716         el->el_line.cursor = el->el_line.lastchar = cp;
717         *cp = '\0';
718         *nread = (int)(el->el_line.cursor - el->el_line.buffer);
719 done:
720         if (*nread == 0) {
721                 if (num == -1) {
722                         *nread = -1;
723                         errno = el->el_errno;
724                 }
725                 return NULL;
726         } else
727                 return el->el_line.buffer;
728 }