xref: /freebsd/usr.bin/sed/compile.c (revision 2e3f49888ec8851bafb22011533217487764fdb0)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1992 Diomidis Spinellis.
5  * Copyright (c) 1992, 1993
6  *	The Regents of the University of California.  All rights reserved.
7  *
8  * This code is derived from software contributed to Berkeley by
9  * Diomidis Spinellis of Imperial College, University of London.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include <sys/cdefs.h>
37 
38 #include <sys/types.h>
39 #include <sys/stat.h>
40 
41 #include <ctype.h>
42 #include <err.h>
43 #include <errno.h>
44 #include <fcntl.h>
45 #include <limits.h>
46 #include <regex.h>
47 #include <stdbool.h>
48 #include <stdio.h>
49 #include <stdlib.h>
50 #include <string.h>
51 #include <wchar.h>
52 
53 #include "defs.h"
54 #include "extern.h"
55 
56 #define LHSZ	128
57 #define	LHMASK	(LHSZ - 1)
58 static struct labhash {
59 	struct	labhash *lh_next;
60 	u_int	lh_hash;
61 	struct	s_command *lh_cmd;
62 	int	lh_ref;
63 } *labels[LHSZ];
64 
65 static char	 *compile_addr(char *, struct s_addr *);
66 static char	 *compile_ccl(char **, char *);
67 static char	 *compile_delimited(char *, char *, int);
68 static char	 *compile_flags(char *, struct s_subst *);
69 static regex_t	 *compile_re(char *, int);
70 static char	 *compile_subst(char *, struct s_subst *);
71 static char	 *compile_text(void);
72 static char	 *compile_tr(char *, struct s_tr **);
73 static struct s_command
74 		**compile_stream(struct s_command **);
75 static char	 *duptoeol(char *, const char *);
76 static void	  enterlabel(struct s_command *);
77 static struct s_command
78 		 *findlabel(char *);
79 static void	  fixuplabel(struct s_command *, struct s_command *);
80 static void	  uselabel(void);
81 
82 /*
83  * Command specification.  This is used to drive the command parser.
84  */
85 struct s_format {
86 	char code;				/* Command code */
87 	int naddr;				/* Number of address args */
88 	enum e_args args;			/* Argument type */
89 };
90 
91 static struct s_format cmd_fmts[] = {
92 	{'{', 2, GROUP},
93 	{'}', 0, ENDGROUP},
94 	{'a', 1, TEXT},
95 	{'b', 2, BRANCH},
96 	{'c', 2, TEXT},
97 	{'d', 2, EMPTY},
98 	{'D', 2, EMPTY},
99 	{'g', 2, EMPTY},
100 	{'G', 2, EMPTY},
101 	{'h', 2, EMPTY},
102 	{'H', 2, EMPTY},
103 	{'i', 1, TEXT},
104 	{'l', 2, EMPTY},
105 	{'n', 2, EMPTY},
106 	{'N', 2, EMPTY},
107 	{'p', 2, EMPTY},
108 	{'P', 2, EMPTY},
109 	{'q', 1, EMPTY},
110 	{'r', 1, RFILE},
111 	{'s', 2, SUBST},
112 	{'t', 2, BRANCH},
113 	{'w', 2, WFILE},
114 	{'x', 2, EMPTY},
115 	{'y', 2, TR},
116 	{'!', 2, NONSEL},
117 	{':', 0, LABEL},
118 	{'#', 0, COMMENT},
119 	{'=', 1, EMPTY},
120 	{'\0', 0, COMMENT},
121 };
122 
123 /* The compiled program. */
124 struct s_command *prog;
125 
126 /*
127  * Compile the program into prog.
128  * Initialise appends.
129  */
130 void
131 compile(void)
132 {
133 	*compile_stream(&prog) = NULL;
134 	fixuplabel(prog, NULL);
135 	uselabel();
136 	if (appendnum == 0)
137 		appends = NULL;
138 	else if ((appends = malloc(sizeof(struct s_appends) * appendnum)) ==
139 	    NULL)
140 		err(1, "malloc");
141 	if ((match = malloc((maxnsub + 1) * sizeof(regmatch_t))) == NULL)
142 		err(1, "malloc");
143 }
144 
145 #define EATSPACE() do {							\
146 	if (p)								\
147 		while (*p && isspace((unsigned char)*p))                \
148 			p++;						\
149 	} while (0)
150 
151 static struct s_command **
152 compile_stream(struct s_command **link)
153 {
154 	char *p;
155 	static char lbuf[_POSIX2_LINE_MAX + 1];	/* To save stack */
156 	struct s_command *cmd, *cmd2, *stack;
157 	struct s_format *fp;
158 	char re[_POSIX2_LINE_MAX + 1];
159 	int naddr;				/* Number of addresses */
160 
161 	stack = NULL;
162 	for (;;) {
163 		if ((p = cu_fgets(lbuf, sizeof(lbuf), NULL)) == NULL) {
164 			if (stack != NULL)
165 				errx(1, "%lu: %s: unexpected EOF (pending }'s)",
166 							linenum, fname);
167 			return (link);
168 		}
169 
170 semicolon:	EATSPACE();
171 		if (p) {
172 			if (*p == '#' || *p == '\0')
173 				continue;
174 			else if (*p == ';') {
175 				p++;
176 				goto semicolon;
177 			}
178 		}
179 		if ((*link = cmd = malloc(sizeof(struct s_command))) == NULL)
180 			err(1, "malloc");
181 		link = &cmd->next;
182 		cmd->startline = cmd->nonsel = 0;
183 		/* First parse the addresses */
184 		naddr = 0;
185 
186 /* Valid characters to start an address */
187 #define	addrchar(c)	(strchr("0123456789/\\$", (c)))
188 		if (addrchar(*p)) {
189 			naddr++;
190 			if ((cmd->a1 = malloc(sizeof(struct s_addr))) == NULL)
191 				err(1, "malloc");
192 			p = compile_addr(p, cmd->a1);
193 			EATSPACE();				/* EXTENSION */
194 			if (*p == ',') {
195 				p++;
196 				EATSPACE();			/* EXTENSION */
197 				naddr++;
198 				if ((cmd->a2 = malloc(sizeof(struct s_addr)))
199 				    == NULL)
200 					err(1, "malloc");
201 				p = compile_addr(p, cmd->a2);
202 				EATSPACE();
203 			} else
204 				cmd->a2 = NULL;
205 		} else
206 			cmd->a1 = cmd->a2 = NULL;
207 
208 nonsel:		/* Now parse the command */
209 		if (!*p)
210 			errx(1, "%lu: %s: command expected", linenum, fname);
211 		cmd->code = *p;
212 		for (fp = cmd_fmts; fp->code; fp++)
213 			if (fp->code == *p)
214 				break;
215 		if (!fp->code)
216 			errx(1, "%lu: %s: invalid command code %c", linenum, fname, *p);
217 		if (naddr > fp->naddr)
218 			errx(1,
219 				"%lu: %s: command %c expects up to %d address(es), found %d",
220 				linenum, fname, *p, fp->naddr, naddr);
221 		switch (fp->args) {
222 		case NONSEL:			/* ! */
223 			p++;
224 			EATSPACE();
225 			cmd->nonsel = 1;
226 			goto nonsel;
227 		case GROUP:			/* { */
228 			p++;
229 			EATSPACE();
230 			cmd->next = stack;
231 			stack = cmd;
232 			link = &cmd->u.c;
233 			if (*p)
234 				goto semicolon;
235 			break;
236 		case ENDGROUP:
237 			/*
238 			 * Short-circuit command processing, since end of
239 			 * group is really just a noop.
240 			 */
241 			cmd->nonsel = 1;
242 			if (stack == NULL)
243 				errx(1, "%lu: %s: unexpected }", linenum, fname);
244 			cmd2 = stack;
245 			stack = cmd2->next;
246 			cmd2->next = cmd;
247 			/*FALLTHROUGH*/
248 		case EMPTY:		/* d D g G h H l n N p P q x = \0 */
249 			p++;
250 			EATSPACE();
251 			if (*p == ';') {
252 				p++;
253 				link = &cmd->next;
254 				goto semicolon;
255 			}
256 			if (*p)
257 				errx(1, "%lu: %s: extra characters at the end of %c command",
258 						linenum, fname, cmd->code);
259 			break;
260 		case TEXT:			/* a c i */
261 			p++;
262 			EATSPACE();
263 			if (*p != '\\')
264 				errx(1,
265 "%lu: %s: command %c expects \\ followed by text", linenum, fname, cmd->code);
266 			p++;
267 			EATSPACE();
268 			if (*p)
269 				errx(1,
270 				"%lu: %s: extra characters after \\ at the end of %c command",
271 				linenum, fname, cmd->code);
272 			cmd->t = compile_text();
273 			break;
274 		case COMMENT:			/* \0 # */
275 			break;
276 		case WFILE:			/* w */
277 			p++;
278 			EATSPACE();
279 			if (*p == '\0')
280 				errx(1, "%lu: %s: filename expected", linenum, fname);
281 			cmd->t = duptoeol(p, "w command");
282 			if (aflag)
283 				cmd->u.fd = -1;
284 			else if ((cmd->u.fd = open(p,
285 			    O_WRONLY|O_APPEND|O_CREAT|O_TRUNC,
286 			    DEFFILEMODE)) == -1)
287 				err(1, "%s", p);
288 			break;
289 		case RFILE:			/* r */
290 			p++;
291 			EATSPACE();
292 			if (*p == '\0')
293 				errx(1, "%lu: %s: filename expected", linenum, fname);
294 			else
295 				cmd->t = duptoeol(p, "read command");
296 			break;
297 		case BRANCH:			/* b t */
298 			p++;
299 			EATSPACE();
300 			if (*p == '\0')
301 				cmd->t = NULL;
302 			else
303 				cmd->t = duptoeol(p, "branch");
304 			break;
305 		case LABEL:			/* : */
306 			p++;
307 			EATSPACE();
308 			cmd->t = duptoeol(p, "label");
309 			if (strlen(p) == 0)
310 				errx(1, "%lu: %s: empty label", linenum, fname);
311 			enterlabel(cmd);
312 			break;
313 		case SUBST:			/* s */
314 			p++;
315 			if (*p == '\0' || *p == '\\')
316 				errx(1,
317 "%lu: %s: substitute pattern can not be delimited by newline or backslash",
318 					linenum, fname);
319 			if ((cmd->u.s = calloc(1, sizeof(struct s_subst))) == NULL)
320 				err(1, "malloc");
321 			p = compile_delimited(p, re, 0);
322 			if (p == NULL)
323 				errx(1,
324 				"%lu: %s: unterminated substitute pattern", linenum, fname);
325 
326 			/* Compile RE with no case sensitivity temporarily */
327 			if (*re == '\0')
328 				cmd->u.s->re = NULL;
329 			else
330 				cmd->u.s->re = compile_re(re, 0);
331 			--p;
332 			p = compile_subst(p, cmd->u.s);
333 			p = compile_flags(p, cmd->u.s);
334 
335 			/* Recompile RE with case sensitivity from "I" flag if any */
336 			if (*re == '\0')
337 				cmd->u.s->re = NULL;
338 			else
339 				cmd->u.s->re = compile_re(re, cmd->u.s->icase);
340 			EATSPACE();
341 			if (*p == ';') {
342 				p++;
343 				link = &cmd->next;
344 				goto semicolon;
345 			}
346 			break;
347 		case TR:			/* y */
348 			p++;
349 			p = compile_tr(p, &cmd->u.y);
350 			EATSPACE();
351 			if (*p == ';') {
352 				p++;
353 				link = &cmd->next;
354 				goto semicolon;
355 			}
356 			if (*p)
357 				errx(1,
358 "%lu: %s: extra text at the end of a transform command", linenum, fname);
359 			break;
360 		}
361 	}
362 }
363 
364 static int
365 hex2char(const char *in, char *out, int len)
366 {
367 	long ord;
368 	char *endptr, hexbuf[3];
369 
370 	hexbuf[0] = in[0];
371 	hexbuf[1] = len > 1 ? in[1] : '\0';
372 	hexbuf[2] = '\0';
373 
374 	errno = 0;
375 	ord = strtol(hexbuf, &endptr, 16);
376 	if (*endptr != '\0' || errno != 0)
377 		return (ERANGE);
378 	*out = (char)ord;
379 	return (0);
380 }
381 
382 static bool
383 hexdigit(char c)
384 {
385 	int lc;
386 
387 	lc = tolower(c);
388 	return isdigit(lc) || (lc >= 'a' && lc <= 'f');
389 }
390 
391 static bool
392 dohex(const char *in, char *out, int *len)
393 {
394 	int tmplen;
395 
396 	if (!hexdigit(in[0]))
397 		return (false);
398 	tmplen = 1;
399 	if (hexdigit(in[1]))
400 		++tmplen;
401 	if (hex2char(in, out, tmplen) == 0) {
402 		*len = tmplen;
403 		return (true);
404 	}
405 
406 	return (false);
407 }
408 
409 /*
410  * Get a delimited string.  P points to the delimiter of the string; d points
411  * to a buffer area.  Newline and delimiter escapes are processed; other
412  * escapes are ignored.
413  *
414  * Returns a pointer to the first character after the final delimiter or NULL
415  * in the case of a non-terminated string.  The character array d is filled
416  * with the processed string.
417  */
418 static char *
419 compile_delimited(char *p, char *d, int is_tr)
420 {
421 	int hexlen;
422 	char c;
423 
424 	c = *p++;
425 	if (c == '\0')
426 		return (NULL);
427 	else if (c == '\\')
428 		errx(1, "%lu: %s: \\ can not be used as a string delimiter",
429 				linenum, fname);
430 	else if (c == '\n')
431 		errx(1, "%lu: %s: newline can not be used as a string delimiter",
432 				linenum, fname);
433 	while (*p) {
434 		if (*p == '[' && *p != c) {
435 			if (!is_tr) {
436 				if ((d = compile_ccl(&p, d)) == NULL) {
437 					errx(1,
438 					    "%lu: %s: unbalanced brackets ([])",
439 					    linenum, fname);
440 				}
441 				continue;
442 			}
443 		} else if (*p == '\\' && p[1] == '[') {
444 			if (is_tr)
445 				p++;
446 			else
447 				*d++ = *p++;
448 		} else if (*p == '\\' && p[1] == c) {
449 			p++;
450 		} else if (*p == '\\' &&
451 		    (p[1] == 'n' || p[1] == 'r' || p[1] == 't')) {
452 			switch (p[1]) {
453 			case 'n':
454 				*d++ = '\n';
455 				break;
456 			case 'r':
457 				*d++ = '\r';
458 				break;
459 			case 't':
460 				*d++ = '\t';
461 				break;
462 			}
463 			p += 2;
464 			continue;
465 		} else if (*p == '\\' && p[1] == 'x') {
466 			if (dohex(&p[2], d, &hexlen)) {
467 				++d;
468 				p += hexlen + 2;
469 				continue;
470 			}
471 		} else if (*p == '\\' && p[1] == '\\') {
472 			if (is_tr)
473 				p++;
474 			else
475 				*d++ = *p++;
476 		} else if (*p == c) {
477 			*d = '\0';
478 			return (p + 1);
479 		}
480 		*d++ = *p++;
481 	}
482 	return (NULL);
483 }
484 
485 
486 /* compile_ccl: expand a POSIX character class */
487 static char *
488 compile_ccl(char **sp, char *t)
489 {
490 	int c, d, hexlen;
491 	char *s = *sp;
492 
493 	*t++ = *s++;
494 	if (*s == '^')
495 		*t++ = *s++;
496 	if (*s == ']')
497 		*t++ = *s++;
498 	for (; *s && (*t = *s) != ']'; s++, t++) {
499 		if (*s == '[' && ((d = *(s+1)) == '.' || d == ':' || d == '=')) {
500 			*++t = *++s, t++, s++;
501 			for (c = *s; (*t = *s) != ']' || c != d; s++, t++)
502 				if ((c = *s) == '\0')
503 					return NULL;
504 		} else if (*s == '\\') {
505 			switch (s[1]) {
506 			case 'n':
507 				*t = '\n';
508 				s++;
509 				break;
510 			case 'r':
511 				*t = '\r';
512 				s++;
513 				break;
514 			case 't':
515 				*t = '\t';
516 				s++;
517 				break;
518 			case 'x':
519 				if (dohex(&s[2], t, &hexlen))
520 					s += hexlen + 1;
521 				break;
522 			}
523 		}
524 	}
525 	return (*s == ']') ? *sp = ++s, ++t : NULL;
526 }
527 
528 /*
529  * Compiles the regular expression in RE and returns a pointer to the compiled
530  * regular expression.
531  * Cflags are passed to regcomp.
532  */
533 static regex_t *
534 compile_re(char *re, int case_insensitive)
535 {
536 	regex_t *rep;
537 	int eval, flags;
538 
539 
540 	flags = rflags;
541 	if (case_insensitive)
542 		flags |= REG_ICASE;
543 	if ((rep = malloc(sizeof(regex_t))) == NULL)
544 		err(1, "malloc");
545 	if ((eval = regcomp(rep, re, flags)) != 0)
546 		errx(1, "%lu: %s: RE error: %s",
547 				linenum, fname, strregerror(eval, rep));
548 	if (maxnsub < rep->re_nsub)
549 		maxnsub = rep->re_nsub;
550 	return (rep);
551 }
552 
553 /*
554  * Compile the substitution string of a regular expression and set res to
555  * point to a saved copy of it.  Nsub is the number of parenthesized regular
556  * expressions.
557  */
558 static char *
559 compile_subst(char *p, struct s_subst *s)
560 {
561 	static char lbuf[_POSIX2_LINE_MAX + 1];
562 	int asize, hexlen, size;
563 	u_char ref;
564 	char c, *text, *op, *sp;
565 	int more = 1, sawesc = 0;
566 
567 	c = *p++;			/* Terminator character */
568 	if (c == '\0')
569 		return (NULL);
570 
571 	s->maxbref = 0;
572 	s->linenum = linenum;
573 	asize = 2 * _POSIX2_LINE_MAX + 1;
574 	if ((text = malloc(asize)) == NULL)
575 		err(1, "malloc");
576 	size = 0;
577 	do {
578 		op = sp = text + size;
579 		for (; *p; p++) {
580 			if (*p == '\\' || sawesc) {
581 				/*
582 				 * If this is a continuation from the last
583 				 * buffer, we won't have a character to
584 				 * skip over.
585 				 */
586 				if (sawesc)
587 					sawesc = 0;
588 				else
589 					p++;
590 
591 				if (*p == '\0') {
592 					/*
593 					 * This escaped character is continued
594 					 * in the next part of the line.  Note
595 					 * this fact, then cause the loop to
596 					 * exit w/ normal EOL case and reenter
597 					 * above with the new buffer.
598 					 */
599 					sawesc = 1;
600 					p--;
601 					continue;
602 				} else if (strchr("123456789", *p) != NULL) {
603 					*sp++ = '\\';
604 					ref = *p - '0';
605 					if (s->re != NULL &&
606 					    ref > s->re->re_nsub)
607 						errx(1, "%lu: %s: \\%c not defined in the RE",
608 								linenum, fname, *p);
609 					if (s->maxbref < ref)
610 						s->maxbref = ref;
611 				} else {
612 					switch (*p) {
613 					case '&':
614 					case '\\':
615 						*sp++ = '\\';
616 						break;
617 					case 'n':
618 						*p = '\n';
619 						break;
620 					case 'r':
621 						*p = '\r';
622 						break;
623 					case 't':
624 						*p = '\t';
625 						break;
626 					case 'x':
627 #define	ADVANCE_N(s, n)					\
628 	do {						\
629 		char *adv = (s);			\
630 		while (*(adv + (n) - 1) != '\0') {	\
631 			*adv = *(adv + (n));		\
632 			++adv;				\
633 		}					\
634 		*adv = '\0';				\
635 	} while (0);
636 						if (dohex(&p[1], p, &hexlen)) {
637 							ADVANCE_N(p + 1,
638 							    hexlen);
639 						}
640 						break;
641 					}
642 				}
643 			} else if (*p == c) {
644 				if (*++p == '\0' && more) {
645 					if (cu_fgets(lbuf, sizeof(lbuf), &more))
646 						p = lbuf;
647 				}
648 				*sp++ = '\0';
649 				size += sp - op;
650 				if ((s->new = realloc(text, size)) == NULL)
651 					err(1, "realloc");
652 				return (p);
653 			} else if (*p == '\n') {
654 				errx(1,
655 "%lu: %s: unescaped newline inside substitute pattern", linenum, fname);
656 				/* NOTREACHED */
657 			}
658 			*sp++ = *p;
659 		}
660 		size += sp - op;
661 		if (asize - size < _POSIX2_LINE_MAX + 1) {
662 			asize *= 2;
663 			if ((text = realloc(text, asize)) == NULL)
664 				err(1, "realloc");
665 		}
666 	} while (cu_fgets(p = lbuf, sizeof(lbuf), &more) != NULL);
667 	errx(1, "%lu: %s: unterminated substitute in regular expression",
668 			linenum, fname);
669 	/* NOTREACHED */
670 }
671 
672 /*
673  * Compile the flags of the s command
674  */
675 static char *
676 compile_flags(char *p, struct s_subst *s)
677 {
678 	int gn;			/* True if we have seen g or n */
679 	unsigned long nval;
680 	char wfile[_POSIX2_LINE_MAX + 1], *q, *eq;
681 
682 	s->n = 1;				/* Default */
683 	s->p = 0;
684 	s->wfile = NULL;
685 	s->wfd = -1;
686 	s->icase = 0;
687 	for (gn = 0;;) {
688 		EATSPACE();			/* EXTENSION */
689 		switch (*p) {
690 		case 'g':
691 			if (gn)
692 				errx(1,
693 "%lu: %s: more than one number or 'g' in substitute flags", linenum, fname);
694 			gn = 1;
695 			s->n = 0;
696 			break;
697 		case '\0':
698 		case '\n':
699 		case ';':
700 			return (p);
701 		case 'p':
702 			s->p = 1;
703 			break;
704 		case 'i':
705 		case 'I':
706 			s->icase = 1;
707 			break;
708 		case '1': case '2': case '3':
709 		case '4': case '5': case '6':
710 		case '7': case '8': case '9':
711 			if (gn)
712 				errx(1,
713 "%lu: %s: more than one number or 'g' in substitute flags", linenum, fname);
714 			gn = 1;
715 			errno = 0;
716 			nval = strtol(p, &p, 10);
717 			if (errno == ERANGE || nval > INT_MAX)
718 				errx(1,
719 "%lu: %s: overflow in the 'N' substitute flag", linenum, fname);
720 			s->n = nval;
721 			p--;
722 			break;
723 		case 'w':
724 			p++;
725 #ifdef HISTORIC_PRACTICE
726 			if (*p != ' ') {
727 				warnx("%lu: %s: space missing before w wfile", linenum, fname);
728 				return (p);
729 			}
730 #endif
731 			EATSPACE();
732 			q = wfile;
733 			eq = wfile + sizeof(wfile) - 1;
734 			while (*p) {
735 				if (*p == '\n')
736 					break;
737 				if (q >= eq)
738 					err(1, "wfile too long");
739 				*q++ = *p++;
740 			}
741 			*q = '\0';
742 			if (q == wfile)
743 				errx(1, "%lu: %s: no wfile specified", linenum, fname);
744 			s->wfile = strdup(wfile);
745 			if (!aflag && (s->wfd = open(wfile,
746 			    O_WRONLY|O_APPEND|O_CREAT|O_TRUNC,
747 			    DEFFILEMODE)) == -1)
748 				err(1, "%s", wfile);
749 			return (p);
750 		default:
751 			errx(1, "%lu: %s: bad flag in substitute command: '%c'",
752 					linenum, fname, *p);
753 			break;
754 		}
755 		p++;
756 	}
757 }
758 
759 /*
760  * Compile a translation set of strings into a lookup table.
761  */
762 static char *
763 compile_tr(char *p, struct s_tr **py)
764 {
765 	struct s_tr *y;
766 	int i;
767 	const char *op, *np;
768 	char old[_POSIX2_LINE_MAX + 1];
769 	char new[_POSIX2_LINE_MAX + 1];
770 	size_t oclen, oldlen, nclen, newlen;
771 	mbstate_t mbs1, mbs2;
772 
773 	if ((*py = y = malloc(sizeof(*y))) == NULL)
774 		err(1, NULL);
775 	y->multis = NULL;
776 	y->nmultis = 0;
777 
778 	if (*p == '\0' || *p == '\\')
779 		errx(1,
780 	"%lu: %s: transform pattern can not be delimited by newline or backslash",
781 			linenum, fname);
782 	p = compile_delimited(p, old, 1);
783 	if (p == NULL)
784 		errx(1, "%lu: %s: unterminated transform source string",
785 				linenum, fname);
786 	p = compile_delimited(p - 1, new, 1);
787 	if (p == NULL)
788 		errx(1, "%lu: %s: unterminated transform target string",
789 				linenum, fname);
790 	EATSPACE();
791 	op = old;
792 	oldlen = mbsrtowcs(NULL, &op, 0, NULL);
793 	if (oldlen == (size_t)-1)
794 		err(1, NULL);
795 	np = new;
796 	newlen = mbsrtowcs(NULL, &np, 0, NULL);
797 	if (newlen == (size_t)-1)
798 		err(1, NULL);
799 	if (newlen != oldlen)
800 		errx(1, "%lu: %s: transform strings are not the same length",
801 				linenum, fname);
802 	if (MB_CUR_MAX == 1) {
803 		/*
804 		 * The single-byte encoding case is easy: generate a
805 		 * lookup table.
806 		 */
807 		for (i = 0; i <= UCHAR_MAX; i++)
808 			y->bytetab[i] = (char)i;
809 		for (; *op; op++, np++)
810 			y->bytetab[(u_char)*op] = *np;
811 	} else {
812 		/*
813 		 * Multi-byte encoding case: generate a lookup table as
814 		 * above, but only for single-byte characters. The first
815 		 * bytes of multi-byte characters have their lookup table
816 		 * entries set to 0, which causes do_tr() to search through
817 		 * an auxiliary vector of multi-byte mappings.
818 		 */
819 		memset(&mbs1, 0, sizeof(mbs1));
820 		memset(&mbs2, 0, sizeof(mbs2));
821 		for (i = 0; i <= UCHAR_MAX; i++)
822 			y->bytetab[i] = (btowc(i) != WEOF) ? i : 0;
823 		while (*op != '\0') {
824 			oclen = mbrlen(op, MB_LEN_MAX, &mbs1);
825 			if (oclen == (size_t)-1 || oclen == (size_t)-2)
826 				errc(1, EILSEQ, NULL);
827 			nclen = mbrlen(np, MB_LEN_MAX, &mbs2);
828 			if (nclen == (size_t)-1 || nclen == (size_t)-2)
829 				errc(1, EILSEQ, NULL);
830 			if (oclen == 1 && nclen == 1)
831 				y->bytetab[(u_char)*op] = *np;
832 			else {
833 				y->bytetab[(u_char)*op] = 0;
834 				y->multis = realloc(y->multis,
835 				    (y->nmultis + 1) * sizeof(*y->multis));
836 				if (y->multis == NULL)
837 					err(1, NULL);
838 				i = y->nmultis++;
839 				y->multis[i].fromlen = oclen;
840 				memcpy(y->multis[i].from, op, oclen);
841 				y->multis[i].tolen = nclen;
842 				memcpy(y->multis[i].to, np, nclen);
843 			}
844 			op += oclen;
845 			np += nclen;
846 		}
847 	}
848 	return (p);
849 }
850 
851 /*
852  * Compile the text following an a, c, or i command.
853  */
854 static char *
855 compile_text(void)
856 {
857 	int asize, esc_nl, size;
858 	char *text, *p, *op, *s;
859 	char lbuf[_POSIX2_LINE_MAX + 1];
860 
861 	asize = 2 * _POSIX2_LINE_MAX + 1;
862 	if ((text = malloc(asize)) == NULL)
863 		err(1, "malloc");
864 	size = 0;
865 	while (cu_fgets(lbuf, sizeof(lbuf), NULL) != NULL) {
866 		op = s = text + size;
867 		p = lbuf;
868 #ifdef LEGACY_BSDSED_COMPAT
869 		EATSPACE();
870 #endif
871 		for (esc_nl = 0; *p != '\0'; p++) {
872 			if (*p == '\\' && p[1] != '\0' && *++p == '\n')
873 				esc_nl = 1;
874 			*s++ = *p;
875 		}
876 		size += s - op;
877 		if (!esc_nl) {
878 			*s = '\0';
879 			break;
880 		}
881 		if (asize - size < _POSIX2_LINE_MAX + 1) {
882 			asize *= 2;
883 			if ((text = realloc(text, asize)) == NULL)
884 				err(1, "realloc");
885 		}
886 	}
887 	text[size] = '\0';
888 	if ((p = realloc(text, size + 1)) == NULL)
889 		err(1, "realloc");
890 	return (p);
891 }
892 
893 /*
894  * Get an address and return a pointer to the first character after
895  * it.  Fill the structure pointed to according to the address.
896  */
897 static char *
898 compile_addr(char *p, struct s_addr *a)
899 {
900 	char *end, re[_POSIX2_LINE_MAX + 1];
901 	int icase;
902 
903 	icase = 0;
904 
905 	a->type = 0;
906 	switch (*p) {
907 	case '\\':				/* Context address */
908 		++p;
909 		/* FALLTHROUGH */
910 	case '/':				/* Context address */
911 		p = compile_delimited(p, re, 0);
912 		if (p == NULL)
913 			errx(1, "%lu: %s: unterminated regular expression", linenum, fname);
914 		/* Check for case insensitive regexp flag */
915 		if (*p == 'I') {
916 			icase = 1;
917 			p++;
918 		}
919 		if (*re == '\0')
920 			a->u.r = NULL;
921 		else
922 			a->u.r = compile_re(re, icase);
923 		a->type = AT_RE;
924 		return (p);
925 
926 	case '$':				/* Last line */
927 		a->type = AT_LAST;
928 		return (p + 1);
929 
930 	case '+':				/* Relative line number */
931 		a->type = AT_RELLINE;
932 		p++;
933 		/* FALLTHROUGH */
934 						/* Line number */
935 	case '0': case '1': case '2': case '3': case '4':
936 	case '5': case '6': case '7': case '8': case '9':
937 		if (a->type == 0)
938 			a->type = AT_LINE;
939 		a->u.l = strtol(p, &end, 10);
940 		return (end);
941 	default:
942 		errx(1, "%lu: %s: expected context address", linenum, fname);
943 		return (NULL);
944 	}
945 }
946 
947 /*
948  * duptoeol --
949  *	Return a copy of all the characters up to \n or \0.
950  */
951 static char *
952 duptoeol(char *s, const char *ctype)
953 {
954 	size_t len;
955 	int ws;
956 	char *p, *start;
957 
958 	ws = 0;
959 	for (start = s; *s != '\0' && *s != '\n'; ++s)
960 		ws = isspace((unsigned char)*s);
961 	*s = '\0';
962 	if (ws)
963 		warnx("%lu: %s: whitespace after %s", linenum, fname, ctype);
964 	len = s - start + 1;
965 	if ((p = malloc(len)) == NULL)
966 		err(1, "malloc");
967 	return (memmove(p, start, len));
968 }
969 
970 /*
971  * Convert goto label names to addresses, and count a and r commands, in
972  * the given subset of the script.  Free the memory used by labels in b
973  * and t commands (but not by :).
974  *
975  * TODO: Remove } nodes
976  */
977 static void
978 fixuplabel(struct s_command *cp, struct s_command *end)
979 {
980 
981 	for (; cp != end; cp = cp->next)
982 		switch (cp->code) {
983 		case 'a':
984 		case 'r':
985 			appendnum++;
986 			break;
987 		case 'b':
988 		case 't':
989 			/* Resolve branch target. */
990 			if (cp->t == NULL) {
991 				cp->u.c = NULL;
992 				break;
993 			}
994 			if ((cp->u.c = findlabel(cp->t)) == NULL)
995 				errx(1, "%lu: %s: undefined label '%s'", linenum, fname, cp->t);
996 			free(cp->t);
997 			break;
998 		case '{':
999 			/* Do interior commands. */
1000 			fixuplabel(cp->u.c, cp->next);
1001 			break;
1002 		}
1003 }
1004 
1005 /*
1006  * Associate the given command label for later lookup.
1007  */
1008 static void
1009 enterlabel(struct s_command *cp)
1010 {
1011 	struct labhash **lhp, *lh;
1012 	u_char *p;
1013 	u_int h, c;
1014 
1015 	for (h = 0, p = (u_char *)cp->t; (c = *p) != 0; p++)
1016 		h = (h << 5) + h + c;
1017 	lhp = &labels[h & LHMASK];
1018 	for (lh = *lhp; lh != NULL; lh = lh->lh_next)
1019 		if (lh->lh_hash == h && strcmp(cp->t, lh->lh_cmd->t) == 0)
1020 			errx(1, "%lu: %s: duplicate label '%s'", linenum, fname, cp->t);
1021 	if ((lh = malloc(sizeof *lh)) == NULL)
1022 		err(1, "malloc");
1023 	lh->lh_next = *lhp;
1024 	lh->lh_hash = h;
1025 	lh->lh_cmd = cp;
1026 	lh->lh_ref = 0;
1027 	*lhp = lh;
1028 }
1029 
1030 /*
1031  * Find the label contained in the command l in the command linked
1032  * list cp.  L is excluded from the search.  Return NULL if not found.
1033  */
1034 static struct s_command *
1035 findlabel(char *name)
1036 {
1037 	struct labhash *lh;
1038 	u_char *p;
1039 	u_int h, c;
1040 
1041 	for (h = 0, p = (u_char *)name; (c = *p) != 0; p++)
1042 		h = (h << 5) + h + c;
1043 	for (lh = labels[h & LHMASK]; lh != NULL; lh = lh->lh_next) {
1044 		if (lh->lh_hash == h && strcmp(name, lh->lh_cmd->t) == 0) {
1045 			lh->lh_ref = 1;
1046 			return (lh->lh_cmd);
1047 		}
1048 	}
1049 	return (NULL);
1050 }
1051 
1052 /*
1053  * Warn about any unused labels.  As a side effect, release the label hash
1054  * table space.
1055  */
1056 static void
1057 uselabel(void)
1058 {
1059 	struct labhash *lh, *next;
1060 	int i;
1061 
1062 	for (i = 0; i < LHSZ; i++) {
1063 		for (lh = labels[i]; lh != NULL; lh = next) {
1064 			next = lh->lh_next;
1065 			if (!lh->lh_ref)
1066 				warnx("%lu: %s: unused label '%s'",
1067 				    linenum, fname, lh->lh_cmd->t);
1068 			free(lh);
1069 		}
1070 	}
1071 }
1072