xref: /netbsd-src/lib/libedit/read.c (revision 2cf0b469b9d048aeccdc6451da18d68a11366991)
1 /*	$NetBSD: read.c,v 1.109 2025/01/03 00:40:08 rillig 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 1.109 2025/01/03 00:40:08 rillig Exp $");
41 #endif
42 #endif /* not lint && not SCCSID */
43 
44 /*
45  * read.c: Terminal read functions
46  */
47 #include <ctype.h>
48 #include <errno.h>
49 #include <fcntl.h>
50 #include <limits.h>
51 #include <stdlib.h>
52 #include <string.h>
53 #include <unistd.h>
54 
55 #include "el.h"
56 #include "fcns.h"
57 #include "read.h"
58 
59 #define	EL_MAXMACRO	10
60 
61 struct macros {
62 	wchar_t	**macro;
63 	int	  level;
64 	int	  offset;
65 };
66 
67 struct el_read_t {
68 	struct macros	 macros;
69 	el_rfunc_t	 read_char;	/* Function to read a character. */
70 	int		 read_errno;
71 };
72 
73 static int	read__fixio(int, int);
74 static int	read_char(EditLine *, wchar_t *);
75 static int	read_getcmd(EditLine *, el_action_t *, wchar_t *);
76 static void	read_clearmacros(struct macros *);
77 static void	read_pop(struct macros *);
78 static const wchar_t *noedit_wgets(EditLine *, int *);
79 
80 /* read_init():
81  *	Initialize the read stuff
82  */
83 libedit_private int
84 read_init(EditLine *el)
85 {
86 	struct macros *ma;
87 
88 	if ((el->el_read = el_malloc(sizeof(*el->el_read))) == NULL)
89 		return -1;
90 
91 	ma = &el->el_read->macros;
92 	if ((ma->macro = el_calloc(EL_MAXMACRO, sizeof(*ma->macro))) == NULL)
93 		goto out;
94 	ma->level = -1;
95 	ma->offset = 0;
96 
97 	/* builtin read_char */
98 	el->el_read->read_char = read_char;
99 	return 0;
100 out:
101 	read_end(el);
102 	return -1;
103 }
104 
105 /* el_read_end():
106  *	Free the data structures used by the read stuff.
107  */
108 libedit_private void
109 read_end(EditLine *el)
110 {
111 
112 	read_clearmacros(&el->el_read->macros);
113 	el_free(el->el_read->macros.macro);
114 	el->el_read->macros.macro = NULL;
115 	el_free(el->el_read);
116 	el->el_read = NULL;
117 }
118 
119 /* el_read_setfn():
120  *	Set the read char function to the one provided.
121  *	If it is set to EL_BUILTIN_GETCFN, then reset to the builtin one.
122  */
123 libedit_private int
124 el_read_setfn(struct el_read_t *el_read, el_rfunc_t rc)
125 {
126 	el_read->read_char = (rc == EL_BUILTIN_GETCFN) ? read_char : rc;
127 	return 0;
128 }
129 
130 
131 /* el_read_getfn():
132  *	return the current read char function, or EL_BUILTIN_GETCFN
133  *	if it is the default one
134  */
135 libedit_private el_rfunc_t
136 el_read_getfn(struct el_read_t *el_read)
137 {
138        return el_read->read_char == read_char ?
139 	    EL_BUILTIN_GETCFN : el_read->read_char;
140 }
141 
142 
143 /* read__fixio():
144  *	Try to recover from a read error
145  */
146 /* ARGSUSED */
147 static int
148 read__fixio(int fd __attribute__((__unused__)), int e)
149 {
150 
151 	switch (e) {
152 	case -1:		/* Make sure that the code is reachable */
153 
154 #ifdef EWOULDBLOCK
155 	case EWOULDBLOCK:
156 #ifndef TRY_AGAIN
157 #define TRY_AGAIN
158 #endif
159 #endif /* EWOULDBLOCK */
160 
161 #if defined(POSIX) && defined(EAGAIN)
162 #if defined(EWOULDBLOCK) && EWOULDBLOCK != EAGAIN
163 	case EAGAIN:
164 #ifndef TRY_AGAIN
165 #define TRY_AGAIN
166 #endif
167 #endif /* EWOULDBLOCK && EWOULDBLOCK != EAGAIN */
168 #endif /* POSIX && EAGAIN */
169 
170 		e = 0;
171 #ifdef TRY_AGAIN
172 #if defined(F_SETFL) && defined(O_NDELAY)
173 		if ((e = fcntl(fd, F_GETFL, 0)) == -1)
174 			return -1;
175 
176 		if (fcntl(fd, F_SETFL, e & ~O_NDELAY) == -1)
177 			return -1;
178 		else
179 			e = 1;
180 #endif /* F_SETFL && O_NDELAY */
181 
182 #ifdef FIONBIO
183 		{
184 			int zero = 0;
185 
186 			if (ioctl(fd, FIONBIO, &zero) == -1)
187 				return -1;
188 			else
189 				e = 1;
190 		}
191 #endif /* FIONBIO */
192 
193 #endif /* TRY_AGAIN */
194 		return e ? 0 : -1;
195 
196 	case EINTR:
197 		return 0;
198 
199 	default:
200 		return -1;
201 	}
202 }
203 
204 
205 /* el_push():
206  *	Push a macro
207  */
208 void
209 el_wpush(EditLine *el, const wchar_t *str)
210 {
211 	struct macros *ma = &el->el_read->macros;
212 
213 	if (str != NULL && ma->level + 1 < EL_MAXMACRO) {
214 		ma->level++;
215 		if ((ma->macro[ma->level] = wcsdup(str)) != NULL)
216 			return;
217 		ma->level--;
218 	}
219 	terminal_beep(el);
220 	terminal__flush(el);
221 }
222 
223 
224 /* read_getcmd():
225  *	Get next command from the input stream,
226  *	return 0 on success or -1 on EOF or error.
227  *	Character values > 255 are not looked up in the map, but inserted.
228  */
229 static int
230 read_getcmd(EditLine *el, el_action_t *cmdnum, wchar_t *ch)
231 {
232 	static const wchar_t meta = (wchar_t)0x80;
233 	el_action_t cmd;
234 
235 	do {
236 		if (el_wgetc(el, ch) != 1)
237 			return -1;
238 
239 #ifdef	KANJI
240 		if ((*ch & meta)) {
241 			el->el_state.metanext = 0;
242 			cmd = CcViMap[' '];
243 			break;
244 		} else
245 #endif /* KANJI */
246 
247 		if (el->el_state.metanext) {
248 			el->el_state.metanext = 0;
249 			*ch |= meta;
250 		}
251 		if (*ch >= N_KEYS)
252 			cmd = ED_INSERT;
253 		else
254 			cmd = el->el_map.current[(unsigned char) *ch];
255 		if (cmd == ED_SEQUENCE_LEAD_IN) {
256 			keymacro_value_t val;
257 			switch (keymacro_get(el, ch, &val)) {
258 			case XK_CMD:
259 				cmd = val.cmd;
260 				break;
261 			case XK_STR:
262 				el_wpush(el, val.str);
263 				break;
264 			case XK_NOD:
265 				return -1;
266 			default:
267 				EL_ABORT((el->el_errfile, "Bad XK_ type \n"));
268 			}
269 		}
270 	} while (cmd == ED_SEQUENCE_LEAD_IN);
271 	*cmdnum = cmd;
272 	return 0;
273 }
274 
275 /* read_char():
276  *	Read a character from the tty.
277  */
278 static int
279 read_char(EditLine *el, wchar_t *cp)
280 {
281 	ssize_t num_read;
282 	int tried = (el->el_flags & FIXIO) == 0;
283 	char cbuf[MB_LEN_MAX];
284 	size_t cbp = 0;
285 	int save_errno = errno;
286 
287  again:
288 	el->el_signal->sig_no = 0;
289 	while ((num_read = read(el->el_infd, cbuf + cbp, (size_t)1)) == -1) {
290 		int e = errno;
291 		switch (el->el_signal->sig_no) {
292 		case SIGCONT:
293 			el_wset(el, EL_REFRESH);
294 			/*FALLTHROUGH*/
295 		case SIGWINCH:
296 			sig_set(el);
297 			goto again;
298 		default:
299 			break;
300 		}
301 		if (!tried && read__fixio(el->el_infd, e) == 0) {
302 			errno = save_errno;
303 			tried = 1;
304 		} else {
305 			errno = e;
306 			*cp = L'\0';
307 			return -1;
308 		}
309 	}
310 
311 	/* Test for EOF */
312 	if (num_read == 0) {
313 		*cp = L'\0';
314 		return 0;
315 	}
316 
317 	for (;;) {
318 		mbstate_t mbs;
319 
320 		++cbp;
321 		/* This only works because UTF8 is stateless. */
322 		memset(&mbs, 0, sizeof(mbs));
323 		switch (mbrtowc(cp, cbuf, cbp, &mbs)) {
324 		case (size_t)-1:
325 			if (cbp > 1) {
326 				/*
327 				 * Invalid sequence, discard all bytes
328 				 * except the last one.
329 				 */
330 				cbuf[0] = cbuf[cbp - 1];
331 				cbp = 0;
332 				break;
333 			} else {
334 				/* Invalid byte, discard it. */
335 				cbp = 0;
336 				goto again;
337 			}
338 		case (size_t)-2:
339 			if (cbp >= MB_LEN_MAX) {
340 				errno = EILSEQ;
341 				*cp = L'\0';
342 				return -1;
343 			}
344 			/* Incomplete sequence, read another byte. */
345 			goto again;
346 		default:
347 			/* Valid character, process it. */
348 			return 1;
349 		}
350 	}
351 }
352 
353 /* read_pop():
354  *	Pop a macro from the stack
355  */
356 static void
357 read_pop(struct macros *ma)
358 {
359 	int i;
360 
361 	el_free(ma->macro[0]);
362 	for (i = 0; i < ma->level; i++)
363 		ma->macro[i] = ma->macro[i + 1];
364 	ma->level--;
365 	ma->offset = 0;
366 }
367 
368 static void
369 read_clearmacros(struct macros *ma)
370 {
371 	while (ma->level >= 0)
372 		el_free(ma->macro[ma->level--]);
373 	ma->offset = 0;
374 }
375 
376 /* el_wgetc():
377  *	Read a wide character
378  */
379 int
380 el_wgetc(EditLine *el, wchar_t *cp)
381 {
382 	struct macros *ma = &el->el_read->macros;
383 	int num_read;
384 
385 	terminal__flush(el);
386 	for (;;) {
387 		if (ma->level < 0)
388 			break;
389 
390 		if (ma->macro[0][ma->offset] == '\0') {
391 			read_pop(ma);
392 			continue;
393 		}
394 
395 		*cp = ma->macro[0][ma->offset++];
396 
397 		if (ma->macro[0][ma->offset] == '\0') {
398 			/* Needed for QuoteMode On */
399 			read_pop(ma);
400 		}
401 
402 		return 1;
403 	}
404 
405 	if (tty_rawmode(el) < 0)/* make sure the tty is set up correctly */
406 		return 0;
407 
408 	num_read = (*el->el_read->read_char)(el, cp);
409 
410 	/*
411 	 * Remember the original reason of a read failure
412 	 * such that el_wgets() can restore it after doing
413 	 * various cleanup operation that might change errno.
414 	 */
415 	if (num_read < 0)
416 		el->el_read->read_errno = errno;
417 
418 	return num_read;
419 }
420 
421 libedit_private void
422 read_prepare(EditLine *el)
423 {
424 	if (el->el_flags & HANDLE_SIGNALS)
425 		sig_set(el);
426 	if (el->el_flags & NO_TTY)
427 		return;
428 	if ((el->el_flags & (UNBUFFERED|EDIT_DISABLED)) == UNBUFFERED)
429 		tty_rawmode(el);
430 
431 	/* This is relatively cheap, and things go terribly wrong if
432 	   we have the wrong size. */
433 	el_resize(el);
434 	re_clear_display(el);	/* reset the display stuff */
435 	ch_reset(el);
436 	re_refresh(el);		/* print the prompt */
437 
438 	if (el->el_flags & UNBUFFERED)
439 		terminal__flush(el);
440 }
441 
442 libedit_private void
443 read_finish(EditLine *el)
444 {
445 	if ((el->el_flags & UNBUFFERED) == 0)
446 		(void) tty_cookedmode(el);
447 	if (el->el_flags & HANDLE_SIGNALS)
448 		sig_clr(el);
449 }
450 
451 static const wchar_t *
452 noedit_wgets(EditLine *el, int *nread)
453 {
454 	el_line_t	*lp = &el->el_line;
455 	int		 num;
456 
457 	while ((num = (*el->el_read->read_char)(el, lp->lastchar)) == 1) {
458 		if (lp->lastchar + 1 >= lp->limit &&
459 		    !ch_enlargebufs(el, (size_t)2))
460 			break;
461 		lp->lastchar++;
462 		if (el->el_flags & UNBUFFERED ||
463 		    lp->lastchar[-1] == '\r' ||
464 		    lp->lastchar[-1] == '\n')
465 			break;
466 	}
467 	if (num == -1 && errno == EINTR)
468 		lp->lastchar = lp->buffer;
469 	lp->cursor = lp->lastchar;
470 	*lp->lastchar = '\0';
471 	*nread = (int)(lp->lastchar - lp->buffer);
472 	return *nread ? lp->buffer : NULL;
473 }
474 
475 const wchar_t *
476 el_wgets(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 	wchar_t ch;
482 	int nrb;
483 
484 	if (nread == NULL)
485 		nread = &nrb;
486 	*nread = 0;
487 	el->el_read->read_errno = 0;
488 
489 	if (el->el_flags & NO_TTY) {
490 		el->el_line.lastchar = el->el_line.buffer;
491 		return noedit_wgets(el, nread);
492 	}
493 
494 #ifdef FIONREAD
495 	if (el->el_tty.t_mode == EX_IO && el->el_read->macros.level < 0) {
496 		int chrs = 0;
497 
498 		(void) ioctl(el->el_infd, FIONREAD, &chrs);
499 		if (chrs == 0) {
500 			if (tty_rawmode(el) < 0) {
501 				errno = 0;
502 				*nread = 0;
503 				return NULL;
504 			}
505 		}
506 	}
507 #endif /* FIONREAD */
508 
509 	if ((el->el_flags & UNBUFFERED) == 0)
510 		read_prepare(el);
511 
512 	if (el->el_flags & EDIT_DISABLED) {
513 		if ((el->el_flags & UNBUFFERED) == 0)
514 			el->el_line.lastchar = el->el_line.buffer;
515 		terminal__flush(el);
516 		return noedit_wgets(el, nread);
517 	}
518 
519 	for (num = -1; num == -1;) {  /* while still editing this line */
520 		/* if EOF or error */
521 		if (read_getcmd(el, &cmdnum, &ch) == -1)
522 			break;
523 		if ((size_t)cmdnum >= el->el_map.nfunc) /* BUG CHECK command */
524 			continue;	/* try again */
525 		/* now do the real command */
526 		/* vi redo needs these way down the levels... */
527 		el->el_state.thiscmd = cmdnum;
528 		el->el_state.thisch = ch;
529 		if (el->el_map.type == MAP_VI &&
530 		    el->el_map.current == el->el_map.key &&
531 		    el->el_chared.c_redo.pos < el->el_chared.c_redo.lim) {
532 			if (cmdnum == VI_DELETE_PREV_CHAR &&
533 			    el->el_chared.c_redo.pos != el->el_chared.c_redo.buf
534 			    && iswprint(el->el_chared.c_redo.pos[-1]))
535 				el->el_chared.c_redo.pos--;
536 			else
537 				*el->el_chared.c_redo.pos++ = ch;
538 		}
539 		retval = (*el->el_map.func[cmdnum]) (el, ch);
540 
541 		/* save the last command here */
542 		el->el_state.lastcmd = cmdnum;
543 
544 		/* use any return value */
545 		switch (retval) {
546 		case CC_CURSOR:
547 			re_refresh_cursor(el);
548 			break;
549 
550 		case CC_REDISPLAY:
551 			re_clear_lines(el);
552 			re_clear_display(el);
553 			/* FALLTHROUGH */
554 
555 		case CC_REFRESH:
556 			re_refresh(el);
557 			break;
558 
559 		case CC_REFRESH_BEEP:
560 			re_refresh(el);
561 			terminal_beep(el);
562 			break;
563 
564 		case CC_NORM:	/* normal char */
565 			break;
566 
567 		case CC_ARGHACK:	/* Suggested by Rich Salz */
568 			/* <rsalz@pineapple.bbn.com> */
569 			continue;	/* keep going... */
570 
571 		case CC_EOF:	/* end of file typed */
572 			if ((el->el_flags & UNBUFFERED) == 0)
573 				num = 0;
574 			else if (num == -1) {
575 				*el->el_line.lastchar++ = CONTROL('d');
576 				el->el_line.cursor = el->el_line.lastchar;
577 				num = 1;
578 			}
579 			break;
580 
581 		case CC_NEWLINE:	/* normal end of line */
582 			num = (int)(el->el_line.lastchar - el->el_line.buffer);
583 			break;
584 
585 		case CC_FATAL:	/* fatal error, reset to known state */
586 			/* put (real) cursor in a known place */
587 			re_clear_display(el);	/* reset the display stuff */
588 			ch_reset(el);	/* reset the input pointers */
589 			read_clearmacros(&el->el_read->macros);
590 			re_refresh(el); /* print the prompt again */
591 			break;
592 
593 		case CC_ERROR:
594 		default:	/* functions we don't know about */
595 			terminal_beep(el);
596 			terminal__flush(el);
597 			break;
598 		}
599 		el->el_state.argument = 1;
600 		el->el_state.doingarg = 0;
601 		el->el_chared.c_vcmd.action = NOP;
602 		if (el->el_flags & UNBUFFERED)
603 			break;
604 	}
605 
606 	terminal__flush(el);		/* flush any buffered output */
607 	/* make sure the tty is set up correctly */
608 	if ((el->el_flags & UNBUFFERED) == 0) {
609 		read_finish(el);
610 		*nread = num != -1 ? num : 0;
611 	} else
612 		*nread = (int)(el->el_line.lastchar - el->el_line.buffer);
613 
614 	if (*nread == 0) {
615 		if (num == -1) {
616 			*nread = -1;
617 			if (el->el_read->read_errno)
618 				errno = el->el_read->read_errno;
619 		}
620 		return NULL;
621 	} else
622 		return el->el_line.buffer;
623 }
624