xref: /illumos-gate/usr/src/cmd/sed/compile.c (revision ee653ea2dda5dfb303c7021b63e6ca4d2f4d642f)
1 /*
2  * Copyright 2010 Nexenta Systems, Inc.  All rights reserved.
3  * Copyright (c) 1992 Diomidis Spinellis.
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  * Diomidis Spinellis of Imperial College, University of London.
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  * 4. 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 <sys/types.h>
36 #include <sys/stat.h>
37 
38 #include <ctype.h>
39 #include <err.h>
40 #include <errno.h>
41 #include <fcntl.h>
42 #include <limits.h>
43 #include <regex.h>
44 #include <stdio.h>
45 #include <stdlib.h>
46 #include <string.h>
47 #include <wchar.h>
48 #include <libintl.h>
49 #include <note.h>
50 
51 #include "defs.h"
52 #include "extern.h"
53 
54 #define	LHSZ	128
55 #define	LHMASK	(LHSZ - 1)
56 static struct labhash {
57 	struct	labhash *lh_next;
58 	uint_t	lh_hash;
59 	struct	s_command *lh_cmd;
60 	int	lh_ref;
61 } *labels[LHSZ];
62 
63 static char	 *compile_addr(char *, struct s_addr *);
64 static char	 *compile_ccl(char **, char *);
65 static char	 *compile_delimited(char *, char *, int);
66 static char	 *compile_flags(char *, struct s_subst *);
67 static regex_t	 *compile_re(char *, int);
68 static char	 *compile_subst(char *, struct s_subst *);
69 static char	 *compile_text(void);
70 static char	 *compile_tr(char *, struct s_tr **);
71 static struct s_command
72 		**compile_stream(struct s_command **);
73 static char	 *duptoeol(char *, const char *);
74 static void	  enterlabel(struct s_command *);
75 static struct s_command
76 		 *findlabel(char *);
77 static void	  fixuplabel(struct s_command *, struct s_command *);
78 static void	  uselabel(void);
79 
80 /*
81  * Command specification.  This is used to drive the command parser.
82  */
83 struct s_format {
84 	char code;				/* Command code */
85 	int naddr;				/* Number of address args */
86 	enum e_args args;			/* Argument type */
87 };
88 
89 static struct s_format cmd_fmts[] = {
90 	{'{', 2, GROUP},
91 	{'}', 0, ENDGROUP},
92 	{'a', 1, TEXT},
93 	{'b', 2, BRANCH},
94 	{'c', 2, TEXT},
95 	{'d', 2, EMPTY},
96 	{'D', 2, EMPTY},
97 	{'g', 2, EMPTY},
98 	{'G', 2, EMPTY},
99 	{'h', 2, EMPTY},
100 	{'H', 2, EMPTY},
101 	{'i', 1, TEXT},
102 	{'l', 2, EMPTY},
103 	{'n', 2, EMPTY},
104 	{'N', 2, EMPTY},
105 	{'p', 2, EMPTY},
106 	{'P', 2, EMPTY},
107 	{'q', 1, EMPTY},
108 	{'r', 1, RFILE},
109 	{'s', 2, SUBST},
110 	{'t', 2, BRANCH},
111 	{'w', 2, WFILE},
112 	{'x', 2, EMPTY},
113 	{'y', 2, TR},
114 	{'!', 2, NONSEL},
115 	{':', 0, LABEL},
116 	{'#', 0, COMMENT},
117 	{'=', 1, EMPTY},
118 	{'\0', 0, COMMENT},
119 };
120 
121 /* The compiled program. */
122 struct s_command *prog;
123 
124 /*
125  * Compile the program into prog.
126  * Initialise appends.
127  */
128 void
129 compile(void)
130 {
131 	*compile_stream(&prog) = NULL;
132 	fixuplabel(prog, NULL);
133 	uselabel();
134 	if (appendnum == 0)
135 		appends = NULL;
136 	else if ((appends = malloc(sizeof (struct s_appends) * appendnum)) ==
137 	    NULL)
138 		err(1, "malloc");
139 	if ((match = malloc((maxnsub + 1) * sizeof (regmatch_t))) == NULL)
140 		err(1, "malloc");
141 }
142 
143 #define	EATSPACE() do {							\
144 	if (p)								\
145 		while (*p && isspace((unsigned char)*p))                \
146 			p++;						\
147 	_NOTE(CONSTCOND)						\
148 } while (0)
149 
150 static struct s_command **
151 compile_stream(struct s_command **link)
152 {
153 	char *p;
154 	static char lbuf[_POSIX2_LINE_MAX + 1];	/* To save stack */
155 	struct s_command *cmd, *cmd2, *stack;
156 	struct s_format *fp;
157 	char re[_POSIX2_LINE_MAX + 1];
158 	int naddr;				/* Number of addresses */
159 
160 	stack = 0;
161 	for (;;) {
162 		if ((p = cu_fgets(lbuf, sizeof (lbuf), NULL)) == NULL) {
163 			if (stack != 0)
164 				fatal(_("unexpected EOF (pending }'s)"));
165 			return (link);
166 		}
167 
168 semicolon:	EATSPACE();
169 		if (p) {
170 			if (*p == '#' || *p == '\0')
171 				continue;
172 			else if (*p == ';') {
173 				p++;
174 				goto semicolon;
175 			}
176 		}
177 		if ((*link = cmd = malloc(sizeof (struct s_command))) == NULL)
178 			err(1, "malloc");
179 		link = &cmd->next;
180 		cmd->startline = cmd->nonsel = 0;
181 		/* First parse the addresses */
182 		naddr = 0;
183 
184 /* Valid characters to start an address */
185 #define	addrchar(c)	(strchr("0123456789/\\$", (c)))
186 		if (addrchar(*p)) {
187 			naddr++;
188 			if ((cmd->a1 = malloc(sizeof (struct s_addr))) == NULL)
189 				err(1, "malloc");
190 			p = compile_addr(p, cmd->a1);
191 			EATSPACE();				/* EXTENSION */
192 			if (*p == ',') {
193 				p++;
194 				EATSPACE();			/* EXTENSION */
195 				naddr++;
196 				if ((cmd->a2 = malloc(sizeof (struct s_addr)))
197 				    == NULL)
198 					err(1, "malloc");
199 				p = compile_addr(p, cmd->a2);
200 				EATSPACE();
201 			} else
202 				cmd->a2 = 0;
203 		} else
204 			cmd->a1 = cmd->a2 = 0;
205 
206 nonsel:		/* Now parse the command */
207 		if (!*p)
208 			fatal(_("command expected"));
209 		cmd->code = *p;
210 		for (fp = cmd_fmts; fp->code; fp++)
211 			if (fp->code == *p)
212 				break;
213 		if (!fp->code)
214 			fatal(_("invalid command code %c"), *p);
215 		if (naddr > fp->naddr)
216 			fatal(_("command %c expects up to %d address(es), "
217 			    "found %d"), *p, fp->naddr, naddr);
218 		switch (fp->args) {
219 		case NONSEL:			/* ! */
220 			p++;
221 			EATSPACE();
222 			cmd->nonsel = 1;
223 			goto nonsel;
224 		case GROUP:			/* { */
225 			p++;
226 			EATSPACE();
227 			cmd->next = stack;
228 			stack = cmd;
229 			link = &cmd->u.c;
230 			if (*p)
231 				goto semicolon;
232 			break;
233 		case ENDGROUP:
234 			/*
235 			 * Short-circuit command processing, since end of
236 			 * group is really just a noop.
237 			 */
238 			cmd->nonsel = 1;
239 			if (stack == 0)
240 				fatal(_("unexpected }"));
241 			cmd2 = stack;
242 			stack = cmd2->next;
243 			cmd2->next = cmd;
244 			/*FALLTHROUGH*/
245 		case EMPTY:		/* d D g G h H l n N p P q x = \0 */
246 			p++;
247 			EATSPACE();
248 			if (*p == ';') {
249 				p++;
250 				link = &cmd->next;
251 				goto semicolon;
252 			}
253 			if (*p)
254 				fatal(_("extra characters at the end of %c "
255 				    "command"), cmd->code);
256 			break;
257 		case TEXT:			/* a c i */
258 			p++;
259 			EATSPACE();
260 			if (*p != '\\')
261 				fatal(_("command %c expects \\ "
262 				    "followed by text"), cmd->code);
263 			p++;
264 			EATSPACE();
265 			if (*p)
266 				fatal(_("extra characters after \\ "
267 				    "at the end of %c command"),
268 				    cmd->code);
269 			cmd->t = compile_text();
270 			break;
271 		case COMMENT:			/* \0 # */
272 			break;
273 		case WFILE:			/* w */
274 			p++;
275 			EATSPACE();
276 			if (*p == '\0')
277 				fatal(_("filename expected"));
278 			cmd->t = duptoeol(p, "w command");
279 			if (aflag)
280 				cmd->u.fd = -1;
281 			else if ((cmd->u.fd = open(p,
282 			    O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, 0666)) == -1)
283 				err(1, "%s", p);
284 			break;
285 		case RFILE:			/* r */
286 			p++;
287 			EATSPACE();
288 			if (*p == '\0')
289 				fatal(_("filename expected"));
290 			else
291 				cmd->t = duptoeol(p, "read command");
292 			break;
293 		case BRANCH:			/* b t */
294 			p++;
295 			EATSPACE();
296 			if (*p == '\0')
297 				cmd->t = NULL;
298 			else
299 				cmd->t = duptoeol(p, "branch");
300 			break;
301 		case LABEL:			/* : */
302 			p++;
303 			EATSPACE();
304 			cmd->t = duptoeol(p, "label");
305 			if (strlen(p) == 0)
306 				fatal(_("empty label"));
307 			enterlabel(cmd);
308 			break;
309 		case SUBST:			/* s */
310 			p++;
311 			if (*p == '\0' || *p == '\\')
312 				fatal(_("substitute pattern can not "
313 				    "be delimited by newline or backslash"));
314 			if ((cmd->u.s = calloc(1, sizeof (struct s_subst))) ==
315 			    NULL)
316 				err(1, "malloc");
317 			p = compile_delimited(p, re, 0);
318 			if (p == NULL)
319 				fatal(_("unterminated substitute pattern"));
320 
321 			/* Compile RE with no case sensitivity temporarily */
322 			if (*re == '\0')
323 				cmd->u.s->re = NULL;
324 			else
325 				cmd->u.s->re = compile_re(re, 0);
326 			--p;
327 			p = compile_subst(p, cmd->u.s);
328 			p = compile_flags(p, cmd->u.s);
329 
330 			/* Recompile RE with case sens. from "I" flag if any */
331 			if (*re == '\0')
332 				cmd->u.s->re = NULL;
333 			else
334 				cmd->u.s->re = compile_re(re, cmd->u.s->icase);
335 			EATSPACE();
336 			if (*p == ';') {
337 				p++;
338 				link = &cmd->next;
339 				goto semicolon;
340 			}
341 			break;
342 		case TR:			/* y */
343 			p++;
344 			p = compile_tr(p, &cmd->u.y);
345 			EATSPACE();
346 			if (*p == ';') {
347 				p++;
348 				link = &cmd->next;
349 				goto semicolon;
350 			}
351 			if (*p)
352 				fatal(_("extra text at the end of a "
353 				    "transform command"));
354 			break;
355 		}
356 	}
357 }
358 
359 /*
360  * Get a delimited string.  P points to the delimeter of the string; d points
361  * to a buffer area.  Newline and delimiter escapes are processed; other
362  * escapes are ignored.
363  *
364  * Returns a pointer to the first character after the final delimiter or NULL
365  * in the case of a non-terminated string.  The character array d is filled
366  * with the processed string.
367  */
368 static char *
369 compile_delimited(char *p, char *d, int is_tr)
370 {
371 	char c;
372 
373 	c = *p++;
374 	if (c == '\0')
375 		return (NULL);
376 	else if (c == '\\')
377 		fatal(_("\\ can not be used as a string delimiter"));
378 	else if (c == '\n')
379 		fatal(_("newline can not be used as a string delimiter"));
380 	while (*p) {
381 		if (*p == '[' && *p != c) {
382 			if ((d = compile_ccl(&p, d)) == NULL)
383 				fatal(_("unbalanced brackets ([])"));
384 			continue;
385 		} else if (*p == '\\' && p[1] == '[') {
386 			*d++ = *p++;
387 		} else if (*p == '\\' && p[1] == c) {
388 			p++;
389 		} else if (*p == '\\' &&
390 		    (p[1] == 'n' || p[1] == 'r' || p[1] == 't')) {
391 			switch (p[1]) {
392 			case 'n':
393 				*d++ = '\n';
394 				break;
395 			case 'r':
396 				*d++ = '\r';
397 				break;
398 			case 't':
399 				*d++ = '\t';
400 				break;
401 			}
402 			p += 2;
403 			continue;
404 		} else if (*p == '\\' && p[1] == '\\') {
405 			if (is_tr)
406 				p++;
407 			else
408 				*d++ = *p++;
409 		} else if (*p == c) {
410 			*d = '\0';
411 			return (p + 1);
412 		}
413 		*d++ = *p++;
414 	}
415 	return (NULL);
416 }
417 
418 
419 /* compile_ccl: expand a POSIX character class */
420 static char *
421 compile_ccl(char **sp, char *t)
422 {
423 	int c, d;
424 	char *s = *sp;
425 
426 	*t++ = *s++;
427 	if (*s == '^')
428 		*t++ = *s++;
429 	if (*s == ']')
430 		*t++ = *s++;
431 	for (; *s && (*t = *s) != ']'; s++, t++) {
432 		if (*s == '[' &&
433 		    ((d = *(s+1)) == '.' || d == ':' || d == '=')) {
434 			*++t = *++s, t++, s++;
435 			for (c = *s; (*t = *s) != ']' || c != d; s++, t++)
436 				if ((c = *s) == '\0')
437 					return (NULL);
438 		} else if (*s == '\\') {
439 			switch (s[1]) {
440 			case 'n':
441 				*t = '\n';
442 				s++;
443 				break;
444 			case 'r':
445 				*t = '\r';
446 				s++;
447 				break;
448 			case 't':
449 				*t = '\t';
450 				s++;
451 				break;
452 			}
453 		}
454 	}
455 	return ((*s == ']') ? *sp = ++s, ++t : NULL);
456 }
457 
458 /*
459  * Compiles the regular expression in RE and returns a pointer to the compiled
460  * regular expression.
461  * Cflags are passed to regcomp.
462  */
463 static regex_t *
464 compile_re(char *re, int case_insensitive)
465 {
466 	regex_t *rep;
467 	int eval, flags;
468 
469 
470 	flags = rflags;
471 	if (case_insensitive)
472 		flags |= REG_ICASE;
473 	if ((rep = malloc(sizeof (regex_t))) == NULL)
474 		err(1, "malloc");
475 	if ((eval = regcomp(rep, re, flags)) != 0)
476 		fatal(_("RE error: %s"), strregerror(eval, rep));
477 	if (maxnsub < rep->re_nsub)
478 		maxnsub = rep->re_nsub;
479 	return (rep);
480 }
481 
482 /*
483  * Compile the substitution string of a regular expression and set res to
484  * point to a saved copy of it.  Nsub is the number of parenthesized regular
485  * expressions.
486  */
487 static char *
488 compile_subst(char *p, struct s_subst *s)
489 {
490 	static char lbuf[_POSIX2_LINE_MAX + 1];
491 	int asize;
492 	uintptr_t size;
493 	uchar_t ref;
494 	char c, *text, *op, *sp;
495 	int more = 1, sawesc = 0;
496 
497 	c = *p++;			/* Terminator character */
498 	if (c == '\0')
499 		return (NULL);
500 
501 	s->maxbref = 0;
502 	s->linenum = linenum;
503 	asize = 2 * _POSIX2_LINE_MAX + 1;
504 	if ((text = malloc(asize)) == NULL)
505 		err(1, "malloc");
506 	size = 0;
507 	do {
508 		op = sp = text + size;
509 		for (; *p; p++) {
510 			if (*p == '\\' || sawesc) {
511 				/*
512 				 * If this is a continuation from the last
513 				 * buffer, we won't have a character to
514 				 * skip over.
515 				 */
516 				if (sawesc)
517 					sawesc = 0;
518 				else
519 					p++;
520 
521 				if (*p == '\0') {
522 					/*
523 					 * This escaped character is continued
524 					 * in the next part of the line.  Note
525 					 * this fact, then cause the loop to
526 					 * exit w/ normal EOL case and reenter
527 					 * above with the new buffer.
528 					 */
529 					sawesc = 1;
530 					p--;
531 					continue;
532 				} else if (strchr("123456789", *p) != NULL) {
533 					*sp++ = '\\';
534 					ref = *p - '0';
535 					if (s->re != NULL &&
536 					    ref > s->re->re_nsub)
537 						fatal(_("not defined in "
538 						    "the RE: \\%c"), *p);
539 					if (s->maxbref < ref)
540 						s->maxbref = ref;
541 				} else {
542 					switch (*p) {
543 					case '&':
544 					case '\\':
545 						*sp++ = '\\';
546 						break;
547 					case 'n':
548 						*p = '\n';
549 						break;
550 					case 'r':
551 						*p = '\r';
552 						break;
553 					case 't':
554 						*p = '\t';
555 						break;
556 					}
557 				}
558 			} else if (*p == c) {
559 				if (*++p == '\0' && more) {
560 					if (cu_fgets(lbuf, sizeof (lbuf),
561 					    &more))
562 						p = lbuf;
563 				}
564 				*sp++ = '\0';
565 				size += (uintptr_t)sp - (uintptr_t)op;
566 				if ((s->new = realloc(text, size)) == NULL)
567 					err(1, "realloc");
568 				return (p);
569 			} else if (*p == '\n') {
570 				fatal(_("unescaped newline inside "
571 				    "substitute pattern"));
572 				/* NOTREACHED */
573 			}
574 			*sp++ = *p;
575 		}
576 		size += (uintptr_t)sp - (uintptr_t)op;
577 		if (asize - size < _POSIX2_LINE_MAX + 1) {
578 			asize *= 2;
579 			if ((text = realloc(text, asize)) == NULL)
580 				err(1, "realloc");
581 		}
582 	} while (cu_fgets(p = lbuf, sizeof (lbuf), &more));
583 	fatal(_("unterminated substitute in regular expression"));
584 	return (NULL);
585 }
586 
587 /*
588  * Compile the flags of the s command
589  */
590 static char *
591 compile_flags(char *p, struct s_subst *s)
592 {
593 	int gn;			/* True if we have seen g or n */
594 	unsigned long nval;
595 	char wfile[_POSIX2_LINE_MAX + 1], *q;
596 
597 	s->n = 1;				/* Default */
598 	s->p = 0;
599 	s->wfile = NULL;
600 	s->wfd = -1;
601 	s->icase = 0;
602 	gn = 0;
603 	for (;;) {
604 		EATSPACE();			/* EXTENSION */
605 		switch (*p) {
606 		case 'g':
607 			if (gn)
608 				fatal(_("more than one number or "
609 				    "'g' in substitute flags"));
610 			gn = 1;
611 			s->n = 0;
612 			break;
613 		case '\0':
614 		case '\n':
615 		case ';':
616 			return (p);
617 		case 'p':
618 			s->p = 1;
619 			break;
620 		case 'I':
621 			s->icase = 1;
622 			break;
623 		case '1': case '2': case '3':
624 		case '4': case '5': case '6':
625 		case '7': case '8': case '9':
626 			if (gn)
627 				fatal(_("more than one number or "
628 				    "'g' in substitute flags"));
629 			gn = 1;
630 			errno = 0;
631 			nval = strtol(p, &p, 10);
632 			if (errno == ERANGE || nval > INT_MAX)
633 				fatal(_("overflow in the 'N' substitute flag"));
634 			s->n = nval;
635 			p--;
636 			break;
637 		case 'w':
638 			p++;
639 #ifdef HISTORIC_PRACTICE
640 			if (*p != ' ') {
641 				fatal(_("space missing before w wfile"));
642 				return (p);
643 			}
644 #endif
645 			EATSPACE();
646 			q = wfile;
647 			while (*p) {
648 				if (*p == '\n')
649 					break;
650 				*q++ = *p++;
651 			}
652 			*q = '\0';
653 			if (q == wfile)
654 				fatal(_("no wfile specified"));
655 			s->wfile = strdup(wfile);
656 			if (!aflag && (s->wfd = open(wfile,
657 			    O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, 0666)) == -1)
658 				err(1, "%s", wfile);
659 			return (p);
660 		default:
661 			fatal(_("bad flag in substitute command: '%c'"), *p);
662 			break;
663 		}
664 		p++;
665 	}
666 }
667 
668 /*
669  * Compile a translation set of strings into a lookup table.
670  */
671 static char *
672 compile_tr(char *p, struct s_tr **py)
673 {
674 	struct s_tr *y;
675 	int i;
676 	const char *op, *np;
677 	char old[_POSIX2_LINE_MAX + 1];
678 	char new[_POSIX2_LINE_MAX + 1];
679 	size_t oclen, oldlen, nclen, newlen;
680 	mbstate_t mbs1, mbs2;
681 
682 	if ((*py = y = malloc(sizeof (*y))) == NULL)
683 		err(1, NULL);
684 	y->multis = NULL;
685 	y->nmultis = 0;
686 
687 	if (*p == '\0' || *p == '\\')
688 		fatal(_("transform pattern can not be delimited by "
689 		    "newline or backslash"));
690 	p = compile_delimited(p, old, 1);
691 	if (p == NULL)
692 		fatal(_("unterminated transform source string"));
693 	p = compile_delimited(p - 1, new, 1);
694 	if (p == NULL)
695 		fatal(_("unterminated transform target string"));
696 	EATSPACE();
697 	op = old;
698 	oldlen = mbsrtowcs(NULL, &op, 0, NULL);
699 	if (oldlen == (size_t)-1)
700 		err(1, NULL);
701 	np = new;
702 	newlen = mbsrtowcs(NULL, &np, 0, NULL);
703 	if (newlen == (size_t)-1)
704 		err(1, NULL);
705 	if (newlen != oldlen)
706 		fatal(_("transform strings are not the same length"));
707 	if (MB_CUR_MAX == 1) {
708 		/*
709 		 * The single-byte encoding case is easy: generate a
710 		 * lookup table.
711 		 */
712 		for (i = 0; i <= UCHAR_MAX; i++)
713 			y->bytetab[i] = (char)i;
714 		for (; *op; op++, np++)
715 			y->bytetab[(uchar_t)*op] = *np;
716 	} else {
717 		/*
718 		 * Multi-byte encoding case: generate a lookup table as
719 		 * above, but only for single-byte characters. The first
720 		 * bytes of multi-byte characters have their lookup table
721 		 * entries set to 0, which causes do_tr() to search through
722 		 * an auxiliary vector of multi-byte mappings.
723 		 */
724 		(void) memset(&mbs1, 0, sizeof (mbs1));
725 		(void) memset(&mbs2, 0, sizeof (mbs2));
726 		for (i = 0; i <= UCHAR_MAX; i++)
727 			y->bytetab[i] = (btowc(i) != WEOF) ? (uchar_t)i : 0;
728 		while (*op != '\0') {
729 			oclen = mbrlen(op, MB_LEN_MAX, &mbs1);
730 			if (oclen == (size_t)-1 || oclen == (size_t)-2)
731 				errx(1, "%s", strerror(EILSEQ));
732 			nclen = mbrlen(np, MB_LEN_MAX, &mbs2);
733 			if (nclen == (size_t)-1 || nclen == (size_t)-2)
734 				errx(1, "%s", strerror(EILSEQ));
735 			if (oclen == 1 && nclen == 1)
736 				y->bytetab[(uchar_t)*op] = *np;
737 			else {
738 				y->bytetab[(uchar_t)*op] = 0;
739 				y->multis = realloc(y->multis,
740 				    (y->nmultis + 1) * sizeof (*y->multis));
741 				if (y->multis == NULL)
742 					err(1, NULL);
743 				i = y->nmultis++;
744 				y->multis[i].fromlen = oclen;
745 				(void) memcpy(y->multis[i].from, op, oclen);
746 				y->multis[i].tolen = nclen;
747 				(void) memcpy(y->multis[i].to, np, nclen);
748 			}
749 			op += oclen;
750 			np += nclen;
751 		}
752 	}
753 	return (p);
754 }
755 
756 /*
757  * Compile the text following an a or i command.
758  */
759 static char *
760 compile_text(void)
761 {
762 	int esc_nl;
763 	uintptr_t size, asize;
764 	char *text, *p, *op, *s;
765 	char lbuf[_POSIX2_LINE_MAX + 1];
766 
767 	asize = 2 * _POSIX2_LINE_MAX + 1;
768 	if ((text = malloc(asize)) == NULL)
769 		err(1, "malloc");
770 	size = 0;
771 	while (cu_fgets(lbuf, sizeof (lbuf), NULL)) {
772 		op = s = text + size;
773 		p = lbuf;
774 		EATSPACE();
775 		for (esc_nl = 0; *p != '\0'; p++) {
776 			if (*p == '\\' && p[1] != '\0' && *++p == '\n')
777 				esc_nl = 1;
778 			*s++ = *p;
779 		}
780 		size += (uintptr_t)s - (uintptr_t)op;
781 		if (!esc_nl) {
782 			*s = '\0';
783 			break;
784 		}
785 		if (asize - size < _POSIX2_LINE_MAX + 1) {
786 			asize *= 2;
787 			if ((text = realloc(text, asize)) == NULL)
788 				err(1, "realloc");
789 		}
790 	}
791 	text[size] = '\0';
792 	if ((p = realloc(text, size + 1)) == NULL)
793 		err(1, "realloc");
794 	return (p);
795 }
796 
797 /*
798  * Get an address and return a pointer to the first character after
799  * it.  Fill the structure pointed to according to the address.
800  */
801 static char *
802 compile_addr(char *p, struct s_addr *a)
803 {
804 	char *end, re[_POSIX2_LINE_MAX + 1];
805 	int icase;
806 
807 	icase = 0;
808 
809 	a->type = 0;
810 	switch (*p) {
811 	case '\\':				/* Context address */
812 		++p;
813 		/* FALLTHROUGH */
814 	case '/':				/* Context address */
815 		p = compile_delimited(p, re, 0);
816 		if (p == NULL)
817 			fatal(_("unterminated regular expression"));
818 
819 		/* Check for case insensitive regexp flag */
820 		if (*p == 'I') {
821 			icase = 1;
822 			p++;
823 		}
824 		if (*re == '\0')
825 			a->u.r = NULL;
826 		else
827 			a->u.r = compile_re(re, icase);
828 		a->type = AT_RE;
829 		return (p);
830 
831 	case '$':				/* Last line */
832 		a->type = AT_LAST;
833 		return (p + 1);
834 
835 	case '+':				/* Relative line number */
836 		a->type = AT_RELLINE;
837 		p++;
838 		/* FALLTHROUGH */
839 						/* Line number */
840 	case '0': case '1': case '2': case '3': case '4':
841 	case '5': case '6': case '7': case '8': case '9':
842 		if (a->type == 0)
843 			a->type = AT_LINE;
844 		a->u.l = strtol(p, &end, 10);
845 		return (end);
846 	default:
847 		fatal(_("expected context address"));
848 		return (NULL);
849 	}
850 }
851 
852 /*
853  * duptoeol --
854  *	Return a copy of all the characters up to \n or \0.
855  */
856 static char *
857 duptoeol(char *s, const char *ctype)
858 {
859 	size_t len;
860 	int ws;
861 	char *p, *start;
862 
863 	ws = 0;
864 	for (start = s; *s != '\0' && *s != '\n'; ++s)
865 		ws = isspace((unsigned char)*s);
866 	*s = '\0';
867 	if (ws)
868 		warnx(_("%lu: %s: whitespace after %s"), linenum, fname, ctype);
869 	len = (uintptr_t)s - (uintptr_t)start + 1;
870 	if ((p = malloc(len)) == NULL)
871 		err(1, "malloc");
872 	return (memmove(p, start, len));
873 }
874 
875 /*
876  * Convert goto label names to addresses, and count a and r commands, in
877  * the given subset of the script.  Free the memory used by labels in b
878  * and t commands (but not by :).
879  *
880  * TODO: Remove } nodes
881  */
882 static void
883 fixuplabel(struct s_command *cp, struct s_command *end)
884 {
885 
886 	for (; cp != end; cp = cp->next)
887 		switch (cp->code) {
888 		case 'a':
889 		case 'r':
890 			appendnum++;
891 			break;
892 		case 'b':
893 		case 't':
894 			/* Resolve branch target. */
895 			if (cp->t == NULL) {
896 				cp->u.c = NULL;
897 				break;
898 			}
899 			if ((cp->u.c = findlabel(cp->t)) == NULL)
900 				fatal(_("undefined label '%s'"), cp->t);
901 			free(cp->t);
902 			break;
903 		case '{':
904 			/* Do interior commands. */
905 			fixuplabel(cp->u.c, cp->next);
906 			break;
907 		}
908 }
909 
910 /*
911  * Associate the given command label for later lookup.
912  */
913 static void
914 enterlabel(struct s_command *cp)
915 {
916 	struct labhash **lhp, *lh;
917 	uchar_t *p;
918 	uint_t h, c;
919 
920 	for (h = 0, p = (uchar_t *)cp->t; (c = *p) != 0; p++)
921 		h = (h << 5) + h + c;
922 	lhp = &labels[h & LHMASK];
923 	for (lh = *lhp; lh != NULL; lh = lh->lh_next)
924 		if (lh->lh_hash == h && strcmp(cp->t, lh->lh_cmd->t) == 0)
925 			fatal(_("duplicate label '%s'"), cp->t);
926 	if ((lh = malloc(sizeof (*lh))) == NULL)
927 		err(1, "malloc");
928 	lh->lh_next = *lhp;
929 	lh->lh_hash = h;
930 	lh->lh_cmd = cp;
931 	lh->lh_ref = 0;
932 	*lhp = lh;
933 }
934 
935 /*
936  * Find the label contained in the command l in the command linked
937  * list cp.  L is excluded from the search.  Return NULL if not found.
938  */
939 static struct s_command *
940 findlabel(char *name)
941 {
942 	struct labhash *lh;
943 	uchar_t *p;
944 	uint_t h, c;
945 
946 	for (h = 0, p = (uchar_t *)name; (c = *p) != 0; p++)
947 		h = (h << 5) + h + c;
948 	for (lh = labels[h & LHMASK]; lh != NULL; lh = lh->lh_next) {
949 		if (lh->lh_hash == h && strcmp(name, lh->lh_cmd->t) == 0) {
950 			lh->lh_ref = 1;
951 			return (lh->lh_cmd);
952 		}
953 	}
954 	return (NULL);
955 }
956 
957 /*
958  * Warn about any unused labels.  As a side effect, release the label hash
959  * table space.
960  */
961 static void
962 uselabel(void)
963 {
964 	struct labhash *lh, *next;
965 	int i;
966 
967 	for (i = 0; i < LHSZ; i++) {
968 		for (lh = labels[i]; lh != NULL; lh = next) {
969 			next = lh->lh_next;
970 			if (!lh->lh_ref)
971 				warnx(_("%lu: %s: unused label '%s'"),
972 				    linenum, fname, lh->lh_cmd->t);
973 			free(lh);
974 		}
975 	}
976 }
977