xref: /dragonfly/usr.bin/sed/compile.c (revision 2d8a3be7)
1 /*-
2  * Copyright (c) 1992 Diomidis Spinellis.
3  * Copyright (c) 1992, 1993
4  *	The Regents of the University of California.  All rights reserved.
5  *
6  * This code is derived from software contributed to Berkeley by
7  * Diomidis Spinellis of Imperial College, University of London.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. All advertising materials mentioning features or use of this software
18  *    must display the following acknowledgement:
19  *	This product includes software developed by the University of
20  *	California, Berkeley and its contributors.
21  * 4. Neither the name of the University nor the names of its contributors
22  *    may be used to endorse or promote products derived from this software
23  *    without specific prior written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35  * SUCH DAMAGE.
36  *
37  * @(#)compile.c	8.1 (Berkeley) 6/6/93
38  * $FreeBSD: src/usr.bin/sed/compile.c,v 1.13.2.8 2002/08/17 05:47:06 tjr Exp $
39  * $DragonFly: src/usr.bin/sed/compile.c,v 1.3 2003/10/04 20:36:50 hmp Exp $
40  */
41 
42 #include <sys/types.h>
43 #include <sys/stat.h>
44 
45 #include <ctype.h>
46 #include <err.h>
47 #include <fcntl.h>
48 #include <limits.h>
49 #include <regex.h>
50 #include <stdio.h>
51 #include <stdlib.h>
52 #include <string.h>
53 
54 #include "defs.h"
55 #include "extern.h"
56 
57 #define LHSZ	128
58 #define	LHMASK	(LHSZ - 1)
59 static struct labhash {
60 	struct	labhash *lh_next;
61 	u_int	lh_hash;
62 	struct	s_command *lh_cmd;
63 	int	lh_ref;
64 } *labels[LHSZ];
65 
66 static char	 *compile_addr(char *, struct s_addr *);
67 static char	 *compile_ccl(char **, char *);
68 static char	 *compile_delimited(char *, char *);
69 static char	 *compile_flags(char *, struct s_subst *);
70 static char	 *compile_re(char *, regex_t **);
71 static char	 *compile_subst(char *, struct s_subst *);
72 static char	 *compile_text(void);
73 static char	 *compile_tr(char *, char **);
74 static struct s_command
75 		**compile_stream(struct s_command **);
76 static char	 *duptoeol(char *, const char *);
77 static void	  enterlabel(struct s_command *);
78 static struct s_command
79 		 *findlabel(char *);
80 static void	  fixuplabel(struct s_command *, struct s_command *);
81 static void	  uselabel(void);
82 
83 /*
84  * Command specification.  This is used to drive the command parser.
85  */
86 struct s_format {
87 	char code;				/* Command code */
88 	int naddr;				/* Number of address args */
89 	enum e_args args;			/* Argument type */
90 };
91 
92 static struct s_format cmd_fmts[] = {
93 	{'{', 2, GROUP},
94 	{'}', 0, ENDGROUP},
95 	{'a', 1, TEXT},
96 	{'b', 2, BRANCH},
97 	{'c', 2, TEXT},
98 	{'d', 2, EMPTY},
99 	{'D', 2, EMPTY},
100 	{'g', 2, EMPTY},
101 	{'G', 2, EMPTY},
102 	{'h', 2, EMPTY},
103 	{'H', 2, EMPTY},
104 	{'i', 1, TEXT},
105 	{'l', 2, EMPTY},
106 	{'n', 2, EMPTY},
107 	{'N', 2, EMPTY},
108 	{'p', 2, EMPTY},
109 	{'P', 2, EMPTY},
110 	{'q', 1, EMPTY},
111 	{'r', 1, RFILE},
112 	{'s', 2, SUBST},
113 	{'t', 2, BRANCH},
114 	{'w', 2, WFILE},
115 	{'x', 2, EMPTY},
116 	{'y', 2, TR},
117 	{'!', 2, NONSEL},
118 	{':', 0, LABEL},
119 	{'#', 0, COMMENT},
120 	{'=', 1, EMPTY},
121 	{'\0', 0, COMMENT},
122 };
123 
124 /* The compiled program. */
125 struct s_command *prog;
126 
127 /*
128  * Compile the program into prog.
129  * Initialise appends.
130  */
131 void
132 compile(void)
133 {
134 	*compile_stream(&prog) = NULL;
135 	fixuplabel(prog, NULL);
136 	uselabel();
137 	if (appendnum == 0)
138 		appends = NULL;
139 	else if ((appends = malloc(sizeof(struct s_appends) * appendnum)) ==
140 	    NULL)
141 		err(1, "malloc");
142 	if ((match = malloc((maxnsub + 1) * sizeof(regmatch_t))) == NULL)
143 		err(1, "malloc");
144 }
145 
146 #define EATSPACE() do {							\
147 	if (p)								\
148 		while (*p && isspace((unsigned char)*p))                \
149 			p++;						\
150 	} while (0)
151 
152 static struct s_command **
153 compile_stream(struct s_command **link)
154 {
155 	char *p;
156 	static char lbuf[_POSIX2_LINE_MAX + 1];	/* To save stack */
157 	struct s_command *cmd, *cmd2, *stack;
158 	struct s_format *fp;
159 	int naddr;				/* Number of addresses */
160 
161 	stack = 0;
162 	for (;;) {
163 		if ((p = cu_fgets(lbuf, sizeof(lbuf), NULL)) == NULL) {
164 			if (stack != 0)
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->nonsel = cmd->inrange = 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 = 0;
205 		} else
206 			cmd->a1 = cmd->a2 = 0;
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 = ! cmd->nonsel;
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 == 0)
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 = malloc(sizeof(struct s_subst))) == NULL)
320 				err(1, "malloc");
321 			p = compile_re(p, &cmd->u.s->re);
322 			if (p == NULL)
323 				errx(1,
324 				"%lu: %s: unterminated substitute pattern", linenum, fname);
325 			--p;
326 			p = compile_subst(p, cmd->u.s);
327 			p = compile_flags(p, cmd->u.s);
328 			EATSPACE();
329 			if (*p == ';') {
330 				p++;
331 				link = &cmd->next;
332 				goto semicolon;
333 			}
334 			break;
335 		case TR:			/* y */
336 			p++;
337 			p = compile_tr(p, (char **)&cmd->u.y);
338 			EATSPACE();
339 			if (*p == ';') {
340 				p++;
341 				link = &cmd->next;
342 				goto semicolon;
343 			}
344 			if (*p)
345 				errx(1,
346 "%lu: %s: extra text at the end of a transform command", linenum, fname);
347 			break;
348 		}
349 	}
350 }
351 
352 /*
353  * Get a delimited string.  P points to the delimeter of the string; d points
354  * to a buffer area.  Newline and delimiter escapes are processed; other
355  * escapes are ignored.
356  *
357  * Returns a pointer to the first character after the final delimiter or NULL
358  * in the case of a non-terminated string.  The character array d is filled
359  * with the processed string.
360  */
361 static char *
362 compile_delimited(char *p, char *d)
363 {
364 	char c;
365 
366 	c = *p++;
367 	if (c == '\0')
368 		return (NULL);
369 	else if (c == '\\')
370 		errx(1, "%lu: %s: \\ can not be used as a string delimiter",
371 				linenum, fname);
372 	else if (c == '\n')
373 		errx(1, "%lu: %s: newline can not be used as a string delimiter",
374 				linenum, fname);
375 	while (*p) {
376 		if (*p == '[') {
377 			if ((d = compile_ccl(&p, d)) == NULL)
378 				errx(1, "%lu: %s: unbalanced brackets ([])", linenum, fname);
379 			continue;
380 		} else if (*p == '\\' && p[1] == '[') {
381 			*d++ = *p++;
382 		} else if (*p == '\\' && p[1] == c)
383 			p++;
384 		else if (*p == '\\' && p[1] == 'n') {
385 			*d++ = '\n';
386 			p += 2;
387 			continue;
388 		} else if (*p == '\\' && p[1] == '\\')
389 			*d++ = *p++;
390 		else if (*p == c) {
391 			*d = '\0';
392 			return (p + 1);
393 		}
394 		*d++ = *p++;
395 	}
396 	return (NULL);
397 }
398 
399 
400 /* compile_ccl: expand a POSIX character class */
401 static char *
402 compile_ccl(char **sp, char *t)
403 {
404 	int c, d;
405 	char *s = *sp;
406 
407 	*t++ = *s++;
408 	if (*s == '^')
409 		*t++ = *s++;
410 	if (*s == ']')
411 		*t++ = *s++;
412 	for (; *s && (*t = *s) != ']'; s++, t++)
413 		if (*s == '[' && ((d = *(s+1)) == '.' || d == ':' || d == '=')) {
414 			*++t = *++s, t++, s++;
415 			for (c = *s; (*t = *s) != ']' || c != d; s++, t++)
416 				if ((c = *s) == '\0')
417 					return NULL;
418 		} else if (*s == '\\' && s[1] == 'n')
419 			    *t = '\n', s++;
420 	return (*s == ']') ? *sp = ++s, ++t : NULL;
421 }
422 
423 /*
424  * Get a regular expression.  P points to the delimiter of the regular
425  * expression; repp points to the address of a regexp pointer.  Newline
426  * and delimiter escapes are processed; other escapes are ignored.
427  * Returns a pointer to the first character after the final delimiter
428  * or NULL in the case of a non terminated regular expression.  The regexp
429  * pointer is set to the compiled regular expression.
430  * Cflags are passed to regcomp.
431  */
432 static char *
433 compile_re(char *p, regex_t **repp)
434 {
435 	int eval;
436 	char re[_POSIX2_LINE_MAX + 1];
437 
438 	p = compile_delimited(p, re);
439 	if (p && strlen(re) == 0) {
440 		*repp = NULL;
441 		return (p);
442 	}
443 	if ((*repp = malloc(sizeof(regex_t))) == NULL)
444 		err(1, "malloc");
445 	if (p && (eval = regcomp(*repp, re, rflags)) != 0)
446 		errx(1, "%lu: %s: RE error: %s",
447 				linenum, fname, strregerror(eval, *repp));
448 	if (maxnsub < (*repp)->re_nsub)
449 		maxnsub = (*repp)->re_nsub;
450 	return (p);
451 }
452 
453 /*
454  * Compile the substitution string of a regular expression and set res to
455  * point to a saved copy of it.  Nsub is the number of parenthesized regular
456  * expressions.
457  */
458 static char *
459 compile_subst(char *p, struct s_subst *s)
460 {
461 	static char lbuf[_POSIX2_LINE_MAX + 1];
462 	int asize, size;
463 	u_char ref;
464 	char c, *text, *op, *sp;
465 	int more = 1, sawesc = 0;
466 
467 	c = *p++;			/* Terminator character */
468 	if (c == '\0')
469 		return (NULL);
470 
471 	s->maxbref = 0;
472 	s->linenum = linenum;
473 	asize = 2 * _POSIX2_LINE_MAX + 1;
474 	if ((text = malloc(asize)) == NULL)
475 		err(1, "malloc");
476 	size = 0;
477 	do {
478 		op = sp = text + size;
479 		for (; *p; p++) {
480 			if (*p == '\\' || sawesc) {
481 				/*
482 				 * If this is a continuation from the last
483 				 * buffer, we won't have a character to
484 				 * skip over.
485 				 */
486 				if (sawesc)
487 					sawesc = 0;
488 				else
489 					p++;
490 
491 				if (*p == '\0') {
492 					/*
493 					 * This escaped character is continued
494 					 * in the next part of the line.  Note
495 					 * this fact, then cause the loop to
496 					 * exit w/ normal EOL case and reenter
497 					 * above with the new buffer.
498 					 */
499 					sawesc = 1;
500 					p--;
501 					continue;
502 				} else if (strchr("123456789", *p) != NULL) {
503 					*sp++ = '\\';
504 					ref = *p - '0';
505 					if (s->re != NULL &&
506 					    ref > s->re->re_nsub)
507 						errx(1, "%lu: %s: \\%c not defined in the RE",
508 								linenum, fname, *p);
509 					if (s->maxbref < ref)
510 						s->maxbref = ref;
511 				} else if (*p == '&' || *p == '\\')
512 					*sp++ = '\\';
513 			} else if (*p == c) {
514 				if (*++p == '\0' && more) {
515 					if (cu_fgets(lbuf, sizeof(lbuf), &more))
516 						p = lbuf;
517 				}
518 				*sp++ = '\0';
519 				size += sp - op;
520 				if ((s->new = realloc(text, size)) == NULL)
521 					err(1, "realloc");
522 				return (p);
523 			} else if (*p == '\n') {
524 				errx(1,
525 "%lu: %s: unescaped newline inside substitute pattern", linenum, fname);
526 				/* NOTREACHED */
527 			}
528 			*sp++ = *p;
529 		}
530 		size += sp - op;
531 		if (asize - size < _POSIX2_LINE_MAX + 1) {
532 			asize *= 2;
533 			if ((text = realloc(text, asize)) == NULL)
534 				err(1, "realloc");
535 		}
536 	} while (cu_fgets(p = lbuf, sizeof(lbuf), &more));
537 	errx(1, "%lu: %s: unterminated substitute in regular expression",
538 			linenum, fname);
539 	/* NOTREACHED */
540 }
541 
542 /*
543  * Compile the flags of the s command
544  */
545 static char *
546 compile_flags(char *p, struct s_subst *s)
547 {
548 	int gn;			/* True if we have seen g or n */
549 	char wfile[_POSIX2_LINE_MAX + 1], *q;
550 
551 	s->n = 1;				/* Default */
552 	s->p = 0;
553 	s->wfile = NULL;
554 	s->wfd = -1;
555 	for (gn = 0;;) {
556 		EATSPACE();			/* EXTENSION */
557 		switch (*p) {
558 		case 'g':
559 			if (gn)
560 				errx(1,
561 "%lu: %s: more than one number or 'g' in substitute flags", linenum, fname);
562 			gn = 1;
563 			s->n = 0;
564 			break;
565 		case '\0':
566 		case '\n':
567 		case ';':
568 			return (p);
569 		case 'p':
570 			s->p = 1;
571 			break;
572 		case '1': case '2': case '3':
573 		case '4': case '5': case '6':
574 		case '7': case '8': case '9':
575 			if (gn)
576 				errx(1,
577 "%lu: %s: more than one number or 'g' in substitute flags", linenum, fname);
578 			gn = 1;
579 			/* XXX Check for overflow */
580 			s->n = (int)strtol(p, &p, 10);
581 			break;
582 		case 'w':
583 			p++;
584 #ifdef HISTORIC_PRACTICE
585 			if (*p != ' ') {
586 				warnx("%lu: %s: space missing before w wfile", linenum, fname);
587 				return (p);
588 			}
589 #endif
590 			EATSPACE();
591 			q = wfile;
592 			while (*p) {
593 				if (*p == '\n')
594 					break;
595 				*q++ = *p++;
596 			}
597 			*q = '\0';
598 			if (q == wfile)
599 				errx(1, "%lu: %s: no wfile specified", linenum, fname);
600 			s->wfile = strdup(wfile);
601 			if (!aflag && (s->wfd = open(wfile,
602 			    O_WRONLY|O_APPEND|O_CREAT|O_TRUNC,
603 			    DEFFILEMODE)) == -1)
604 				err(1, "%s", wfile);
605 			return (p);
606 		default:
607 			errx(1, "%lu: %s: bad flag in substitute command: '%c'",
608 					linenum, fname, *p);
609 			break;
610 		}
611 		p++;
612 	}
613 }
614 
615 /*
616  * Compile a translation set of strings into a lookup table.
617  */
618 static char *
619 compile_tr(char *p, char **transtab)
620 {
621 	int i;
622 	char *lt, *op, *np;
623 	char old[_POSIX2_LINE_MAX + 1];
624 	char new[_POSIX2_LINE_MAX + 1];
625 
626 	if (*p == '\0' || *p == '\\')
627 		errx(1,
628 	"%lu: %s: transform pattern can not be delimited by newline or backslash",
629 			linenum, fname);
630 	p = compile_delimited(p, old);
631 	if (p == NULL)
632 		errx(1, "%lu: %s: unterminated transform source string",
633 				linenum, fname);
634 	p = compile_delimited(--p, new);
635 	if (p == NULL)
636 		errx(1, "%lu: %s: unterminated transform target string",
637 				linenum, fname);
638 	EATSPACE();
639 	if (strlen(new) != strlen(old))
640 		errx(1, "%lu: %s: transform strings are not the same length",
641 				linenum, fname);
642 	/* We assume characters are 8 bits */
643 	if ((lt = malloc(UCHAR_MAX)) == NULL)
644 		err(1, "malloc");
645 	for (i = 0; i <= UCHAR_MAX; i++)
646 		lt[i] = (char)i;
647 	for (op = old, np = new; *op; op++, np++)
648 		lt[(u_char)*op] = *np;
649 	*transtab = lt;
650 	return (p);
651 }
652 
653 /*
654  * Compile the text following an a or i command.
655  */
656 static char *
657 compile_text(void)
658 {
659 	int asize, esc_nl, size;
660 	char *text, *p, *op, *s;
661 	char lbuf[_POSIX2_LINE_MAX + 1];
662 
663 	asize = 2 * _POSIX2_LINE_MAX + 1;
664 	if ((text = malloc(asize)) == NULL)
665 		err(1, "malloc");
666 	size = 0;
667 	while (cu_fgets(lbuf, sizeof(lbuf), NULL)) {
668 		op = s = text + size;
669 		p = lbuf;
670 		EATSPACE();
671 		for (esc_nl = 0; *p != '\0'; p++) {
672 			if (*p == '\\' && p[1] != '\0' && *++p == '\n')
673 				esc_nl = 1;
674 			*s++ = *p;
675 		}
676 		size += s - op;
677 		if (!esc_nl) {
678 			*s = '\0';
679 			break;
680 		}
681 		if (asize - size < _POSIX2_LINE_MAX + 1) {
682 			asize *= 2;
683 			if ((text = realloc(text, asize)) == NULL)
684 				err(1, "realloc");
685 		}
686 	}
687 	text[size] = '\0';
688 	if ((p = realloc(text, size + 1)) == NULL)
689 		err(1, "realloc");
690 	return (p);
691 }
692 
693 /*
694  * Get an address and return a pointer to the first character after
695  * it.  Fill the structure pointed to according to the address.
696  */
697 static char *
698 compile_addr(char *p, struct s_addr *a)
699 {
700 	char *end;
701 
702 	switch (*p) {
703 	case '\\':				/* Context address */
704 		++p;
705 		/* FALLTHROUGH */
706 	case '/':				/* Context address */
707 		p = compile_re(p, &a->u.r);
708 		if (p == NULL)
709 			errx(1, "%lu: %s: unterminated regular expression", linenum, fname);
710 		a->type = AT_RE;
711 		return (p);
712 
713 	case '$':				/* Last line */
714 		a->type = AT_LAST;
715 		return (p + 1);
716 						/* Line number */
717 	case '0': case '1': case '2': case '3': case '4':
718 	case '5': case '6': case '7': case '8': case '9':
719 		a->type = AT_LINE;
720 		a->u.l = strtol(p, &end, 10);
721 		return (end);
722 	default:
723 		errx(1, "%lu: %s: expected context address", linenum, fname);
724 		return (NULL);
725 	}
726 }
727 
728 /*
729  * duptoeol --
730  *	Return a copy of all the characters up to \n or \0.
731  */
732 static char *
733 duptoeol(char *s, const char *ctype)
734 {
735 	size_t len;
736 	int ws;
737 	char *p, *start;
738 
739 	ws = 0;
740 	for (start = s; *s != '\0' && *s != '\n'; ++s)
741 		ws = isspace((unsigned char)*s);
742 	*s = '\0';
743 	if (ws)
744 		warnx("%lu: %s: whitespace after %s", linenum, fname, ctype);
745 	len = s - start + 1;
746 	if ((p = malloc(len)) == NULL)
747 		err(1, "malloc");
748 	return (memmove(p, start, len));
749 }
750 
751 /*
752  * Convert goto label names to addresses, and count a and r commands, in
753  * the given subset of the script.  Free the memory used by labels in b
754  * and t commands (but not by :).
755  *
756  * TODO: Remove } nodes
757  */
758 static void
759 fixuplabel(struct s_command *cp, struct s_command *end)
760 {
761 
762 	for (; cp != end; cp = cp->next)
763 		switch (cp->code) {
764 		case 'a':
765 		case 'r':
766 			appendnum++;
767 			break;
768 		case 'b':
769 		case 't':
770 			/* Resolve branch target. */
771 			if (cp->t == NULL) {
772 				cp->u.c = NULL;
773 				break;
774 			}
775 			if ((cp->u.c = findlabel(cp->t)) == NULL)
776 				errx(1, "%lu: %s: undefined label '%s'", linenum, fname, cp->t);
777 			free(cp->t);
778 			break;
779 		case '{':
780 			/* Do interior commands. */
781 			fixuplabel(cp->u.c, cp->next);
782 			break;
783 		}
784 }
785 
786 /*
787  * Associate the given command label for later lookup.
788  */
789 static void
790 enterlabel(struct s_command *cp)
791 {
792 	struct labhash **lhp, *lh;
793 	u_char *p;
794 	u_int h, c;
795 
796 	for (h = 0, p = (u_char *)cp->t; (c = *p) != 0; p++)
797 		h = (h << 5) + h + c;
798 	lhp = &labels[h & LHMASK];
799 	for (lh = *lhp; lh != NULL; lh = lh->lh_next)
800 		if (lh->lh_hash == h && strcmp(cp->t, lh->lh_cmd->t) == 0)
801 			errx(1, "%lu: %s: duplicate label '%s'", linenum, fname, cp->t);
802 	if ((lh = malloc(sizeof *lh)) == NULL)
803 		err(1, "malloc");
804 	lh->lh_next = *lhp;
805 	lh->lh_hash = h;
806 	lh->lh_cmd = cp;
807 	lh->lh_ref = 0;
808 	*lhp = lh;
809 }
810 
811 /*
812  * Find the label contained in the command l in the command linked
813  * list cp.  L is excluded from the search.  Return NULL if not found.
814  */
815 static struct s_command *
816 findlabel(char *name)
817 {
818 	struct labhash *lh;
819 	u_char *p;
820 	u_int h, c;
821 
822 	for (h = 0, p = (u_char *)name; (c = *p) != 0; p++)
823 		h = (h << 5) + h + c;
824 	for (lh = labels[h & LHMASK]; lh != NULL; lh = lh->lh_next) {
825 		if (lh->lh_hash == h && strcmp(name, lh->lh_cmd->t) == 0) {
826 			lh->lh_ref = 1;
827 			return (lh->lh_cmd);
828 		}
829 	}
830 	return (NULL);
831 }
832 
833 /*
834  * Warn about any unused labels.  As a side effect, release the label hash
835  * table space.
836  */
837 static void
838 uselabel(void)
839 {
840 	struct labhash *lh, *next;
841 	int i;
842 
843 	for (i = 0; i < LHSZ; i++) {
844 		for (lh = labels[i]; lh != NULL; lh = next) {
845 			next = lh->lh_next;
846 			if (!lh->lh_ref)
847 				warnx("%lu: %s: unused label '%s'",
848 				    linenum, fname, lh->lh_cmd->t);
849 			free(lh);
850 		}
851 	}
852 }
853