xref: /netbsd/usr.bin/sed/process.c (revision eee30e61)
1 /*	$NetBSD: process.c,v 1.53 2020/05/15 22:39:54 christos Exp $	*/
2 
3 /*-
4  * Copyright (c) 1992 Diomidis Spinellis.
5  * Copyright (c) 1992, 1993, 1994
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 #if HAVE_NBTOOL_CONFIG_H
37 #include "nbtool_config.h"
38 #endif
39 
40 #include <sys/cdefs.h>
41 __RCSID("$NetBSD: process.c,v 1.53 2020/05/15 22:39:54 christos Exp $");
42 #ifdef __FBSDID
43 __FBSDID("$FreeBSD: head/usr.bin/sed/process.c 192732 2009-05-25 06:45:33Z brian $");
44 #endif
45 
46 #if 0
47 static const char sccsid[] = "@(#)process.c	8.6 (Berkeley) 4/20/94";
48 #endif
49 
50 #include <sys/types.h>
51 #include <sys/stat.h>
52 #include <sys/ioctl.h>
53 #include <sys/uio.h>
54 
55 #include <ctype.h>
56 #include <err.h>
57 #include <errno.h>
58 #include <fcntl.h>
59 #include <limits.h>
60 #include <regex.h>
61 #include <stdio.h>
62 #include <stdlib.h>
63 #include <string.h>
64 #include <unistd.h>
65 #include <wchar.h>
66 #include <wctype.h>
67 
68 #include "defs.h"
69 #include "extern.h"
70 
71 static SPACE HS, PS, SS, YS;
72 #define	pd		PS.deleted
73 #define	ps		PS.space
74 #define	psl		PS.len
75 #define	psanl		PS.append_newline
76 #define	hs		HS.space
77 #define	hsl		HS.len
78 
79 static __inline int	 applies(struct s_command *);
80 static void		 do_tr(struct s_tr *);
81 static void		 flush_appends(void);
82 static void		 lputs(char *, size_t);
83 static __inline int	 regexec_e(regex_t *, const char *, int, int, size_t);
84 static void		 regsub(SPACE *, char *, char *);
85 static int		 substitute(struct s_command *);
86 
87 struct s_appends *appends;	/* Array of pointers to strings to append. */
88 static size_t appendx;		/* Index into appends array. */
89 size_t appendnum;			/* Size of appends array. */
90 
91 static int lastaddr;		/* Set by applies if last address of a range. */
92 static int sdone;		/* If any substitutes since last line input. */
93 				/* Iov structure for 'w' commands. */
94 static regex_t *defpreg;
95 size_t maxnsub;
96 regmatch_t *match;
97 
98 #define OUT() do {							\
99 	fwrite(ps, 1, psl, outfile);					\
100 	if (psanl) fputc('\n', outfile);				\
101 } while (0)
102 
103 void
process(void)104 process(void)
105 {
106 	struct s_command *cp;
107 	SPACE tspace;
108 	size_t oldpsl = 0;
109 	char *p;
110 	int oldpsanl;
111 
112 	p = NULL;
113 
114 	for (linenum = 0; mf_fgets(&PS, REPLACE);) {
115 		pd = 0;
116 top:
117 		cp = prog;
118 redirect:
119 		while (cp != NULL) {
120 			if (!applies(cp)) {
121 				cp = cp->next;
122 				continue;
123 			}
124 			switch (cp->code) {
125 			case '{':
126 				cp = cp->u.c;
127 				goto redirect;
128 			case 'a':
129 				if (appendx >= appendnum)
130 					appends = xrealloc(appends,
131 					    sizeof(struct s_appends) *
132 					    (appendnum *= 2));
133 				appends[appendx].type = AP_STRING;
134 				appends[appendx].s = cp->t;
135 				appends[appendx].len = strlen(cp->t);
136 				appendx++;
137 				break;
138 			case 'b':
139 				cp = cp->u.c;
140 				goto redirect;
141 			case 'c':
142 				pd = 1;
143 				psl = 0;
144 				if (cp->a2 == NULL || lastaddr || lastline())
145 					(void)fprintf(outfile, "%s", cp->t);
146 				goto new;
147 			case 'd':
148 				pd = 1;
149 				goto new;
150 			case 'D':
151 				if (pd)
152 					goto new;
153 				if (psl == 0 ||
154 				    (p = memchr(ps, '\n', psl - 1)) == NULL) {
155 					pd = 1;
156 					goto new;
157 				} else {
158 					psl -= (size_t)((p + 1) - ps);
159 					memmove(ps, p + 1, psl);
160 					goto top;
161 				}
162 			case 'g':
163 				cspace(&PS, hs, hsl, REPLACE);
164 				break;
165 			case 'G':
166 				cspace(&PS, "\n", 1, APPEND);
167 				cspace(&PS, hs, hsl, APPEND);
168 				break;
169 			case 'h':
170 				cspace(&HS, ps, psl, REPLACE);
171 				break;
172 			case 'H':
173 				cspace(&HS, "\n", 1, APPEND);
174 				cspace(&HS, ps, psl, APPEND);
175 				break;
176 			case 'i':
177 				(void)fprintf(outfile, "%s", cp->t);
178 				break;
179 			case 'l':
180 				lputs(ps, psl);
181 				break;
182 			case 'n':
183 				if (!nflag && !pd)
184 					OUT();
185 				flush_appends();
186 				if (!mf_fgets(&PS, REPLACE))
187 					exit(0);
188 				pd = 0;
189 				break;
190 			case 'N':
191 				flush_appends();
192 				cspace(&PS, "\n", 1, APPEND);
193 				if (!mf_fgets(&PS, APPEND))
194 					exit(0);
195 				break;
196 			case 'p':
197 				if (pd)
198 					break;
199 				OUT();
200 				break;
201 			case 'P':
202 				if (pd)
203 					break;
204 				if ((p = memchr(ps, '\n', psl - 1)) != NULL) {
205 					oldpsl = psl;
206 					oldpsanl = psanl;
207 					psl = (size_t)(p - ps);
208 					psanl = 1;
209 				}
210 				OUT();
211 				if (p != NULL) {
212 					psl = oldpsl;
213 					psanl = oldpsanl;
214 				}
215 				break;
216 			case 'q':
217 				if (!nflag && !pd)
218 					OUT();
219 				flush_appends();
220 				exit(0);
221 			case 'r':
222 				if (appendx >= appendnum)
223 					appends = xrealloc(appends,
224 					    sizeof(struct s_appends) *
225 					    (appendnum *= 2));
226 				appends[appendx].type = AP_FILE;
227 				appends[appendx].s = cp->t;
228 				appends[appendx].len = strlen(cp->t);
229 				appendx++;
230 				break;
231 			case 's':
232 				sdone |= substitute(cp);
233 				break;
234 			case 't':
235 				if (sdone) {
236 					sdone = 0;
237 					cp = cp->u.c;
238 					goto redirect;
239 				}
240 				break;
241 			case 'w':
242 				if (pd)
243 					break;
244 				if (cp->u.fd == -1 && (cp->u.fd = open(cp->t,
245 				    O_WRONLY|O_APPEND|O_CREAT|O_TRUNC,
246 				    DEFFILEMODE)) == -1)
247 					err(1, "%s", cp->t);
248 				if (write(cp->u.fd, ps, psl) != (ssize_t)psl ||
249 				    write(cp->u.fd, "\n", 1) != 1)
250 					err(1, "%s", cp->t);
251 				break;
252 			case 'x':
253 				/*
254 				 * If the hold space is null, make it empty
255 				 * but not null.  Otherwise the pattern space
256 				 * will become null after the swap, which is
257 				 * an abnormal condition.
258 				 */
259 				if (hs == NULL)
260 					cspace(&HS, "", 0, REPLACE);
261 				tspace = PS;
262 				PS = HS;
263 				psanl = tspace.append_newline;
264 				HS = tspace;
265 				break;
266 			case 'y':
267 				if (pd || psl == 0)
268 					break;
269 				do_tr(cp->u.y);
270 				break;
271 			case ':':
272 			case '}':
273 				break;
274 			case '=':
275 				(void)fprintf(outfile, "%lu\n", linenum);
276 			}
277 			cp = cp->next;
278 		} /* for all cp */
279 
280 new:		if (!nflag && !pd)
281 			OUT();
282 		flush_appends();
283 	} /* for all lines */
284 }
285 
286 /*
287  * TRUE if the address passed matches the current program state
288  * (lastline, linenumber, ps).
289  */
290 #define	MATCH(a)							\
291 	((a)->type == AT_RE ? regexec_e((a)->u.r, ps, 0, 1, psl) :	\
292 	    (a)->type == AT_LINE ? linenum == (a)->u.l : lastline())
293 
294 /*
295  * Return TRUE if the command applies to the current line.  Sets the start
296  * line for process ranges.  Interprets the non-select (``!'') flag.
297  */
298 static __inline int
applies(struct s_command * cp)299 applies(struct s_command *cp)
300 {
301 	int r;
302 
303 	lastaddr = 0;
304 	if (cp->a1 == NULL && cp->a2 == NULL)
305 		r = 1;
306 	else if (cp->a2)
307 		if (cp->startline > 0) {
308 			switch (cp->a2->type) {
309 			case AT_RELLINE:
310 				if (linenum - cp->startline <= cp->a2->u.l)
311 					r = 1;
312 				else {
313 					cp->startline = 0;
314 					r = 0;
315 				}
316 				break;
317 			default:
318 				if (MATCH(cp->a2)) {
319 					cp->startline = 0;
320 					lastaddr = 1;
321 					r = 1;
322 				} else if (cp->a2->type == AT_LINE &&
323 				    linenum > cp->a2->u.l) {
324 					/*
325 					 * We missed the 2nd address due to a
326 					 * branch, so just close the range and
327 					 * return false.
328 					 */
329 					cp->startline = 0;
330 					r = 0;
331 				} else
332 					r = 1;
333 			}
334 		} else if (cp->a1 && MATCH(cp->a1)) {
335 			/*
336 			 * If the second address is a number less than or
337 			 * equal to the line number first selected, only
338 			 * one line shall be selected.
339 			 *	-- POSIX 1003.2
340 			 * Likewise if the relative second line address is zero.
341 			 */
342 			if ((cp->a2->type == AT_LINE &&
343 			    linenum >= cp->a2->u.l) ||
344 			    (cp->a2->type == AT_RELLINE && cp->a2->u.l == 0))
345 				lastaddr = 1;
346 			else {
347 				cp->startline = linenum;
348 			}
349 			r = 1;
350 		} else
351 			r = 0;
352 	else
353 		r = MATCH(cp->a1);
354 	return (cp->nonsel ? ! r : r);
355 }
356 
357 /*
358  * Reset the sed processor to its initial state.
359  */
360 void
resetstate(void)361 resetstate(void)
362 {
363 	struct s_command *cp;
364 
365 	/*
366 	 * Reset all in-range markers.
367 	 */
368 	for (cp = prog; cp; cp = cp->code == '{' ? cp->u.c : cp->next)
369 		if (cp->a2)
370 			cp->startline = 0;
371 
372 	/*
373 	 * Clear out the hold space.
374 	 */
375 	cspace(&HS, "", 0, REPLACE);
376 }
377 
378 /*
379  * substitute --
380  *	Do substitutions in the pattern space.  Currently, we build a
381  *	copy of the new pattern space in the substitute space structure
382  *	and then swap them.
383  */
384 static int
substitute(struct s_command * cp)385 substitute(struct s_command *cp)
386 {
387 	SPACE tspace;
388 	regex_t *re;
389 	regoff_t re_off, slen;
390 	int lastempty, n;
391 	char *s;
392 
393 	s = ps;
394 	re = cp->u.s->re;
395 	if (re == NULL) {
396 		if (defpreg != NULL && cp->u.s->maxbref > defpreg->re_nsub) {
397 			linenum = cp->u.s->linenum;
398 			errx(1, "%lu: %s: \\%u not defined in the RE",
399 					linenum, fname, cp->u.s->maxbref);
400 		}
401 	}
402 	if (!regexec_e(re, s, 0, 0, psl))
403 		return (0);
404 
405 	SS.len = 0;				/* Clean substitute space. */
406 	slen = (regoff_t)psl;
407 	n = cp->u.s->n;
408 	lastempty = 1;
409 
410 	switch (n) {
411 	case 0:					/* Global */
412 		do {
413 			if (lastempty || match[0].rm_so != match[0].rm_eo) {
414 				/* Locate start of replaced string. */
415 				re_off = match[0].rm_so;
416 				/* Copy leading retained string. */
417 				cspace(&SS, s, (size_t)re_off, APPEND);
418 				/* Add in regular expression. */
419 				regsub(&SS, s, cp->u.s->new);
420 			}
421 
422 			/* Move past this match. */
423 			if (match[0].rm_so != match[0].rm_eo) {
424 				s += match[0].rm_eo;
425 				slen -= match[0].rm_eo;
426 				lastempty = 0;
427 			} else {
428 				if (match[0].rm_so < slen)
429 					cspace(&SS, s + match[0].rm_so, 1,
430 					    APPEND);
431 				s += match[0].rm_so + 1;
432 				slen -= match[0].rm_so + 1;
433 				lastempty = 1;
434 			}
435 		} while (slen >= 0 && regexec_e(re, s, REG_NOTBOL, 0, (size_t)slen));
436 		/* Copy trailing retained string. */
437 		if (slen > 0)
438 			cspace(&SS, s, (size_t)slen, APPEND);
439 		break;
440 	default:				/* Nth occurrence */
441 		while (--n) {
442 			if (match[0].rm_eo == match[0].rm_so)
443 				match[0].rm_eo = match[0].rm_so + 1;
444 			s += match[0].rm_eo;
445 			slen -= match[0].rm_eo;
446 			if (slen < 0)
447 				return (0);
448 			if (!regexec_e(re, s, REG_NOTBOL, 0, (size_t)slen))
449 				return (0);
450 		}
451 		/* FALLTHROUGH */
452 	case 1:					/* 1st occurrence */
453 		/* Locate start of replaced string. */
454 		re_off = match[0].rm_so + (s - ps);
455 		/* Copy leading retained string. */
456 		cspace(&SS, ps, (size_t)re_off, APPEND);
457 		/* Add in regular expression. */
458 		regsub(&SS, s, cp->u.s->new);
459 		/* Copy trailing retained string. */
460 		s += match[0].rm_eo;
461 		slen -= match[0].rm_eo;
462 		cspace(&SS, s, (size_t)slen, APPEND);
463 		break;
464 	}
465 
466 	/*
467 	 * Swap the substitute space and the pattern space, and make sure
468 	 * that any leftover pointers into stdio memory get lost.
469 	 */
470 	tspace = PS;
471 	PS = SS;
472 	psanl = tspace.append_newline;
473 	SS = tspace;
474 	SS.space = SS.back;
475 
476 	/* Handle the 'p' flag. */
477 	if (cp->u.s->p)
478 		OUT();
479 
480 	/* Handle the 'w' flag. */
481 	if (cp->u.s->wfile && !pd) {
482 		if (cp->u.s->wfd == -1 && (cp->u.s->wfd = open(cp->u.s->wfile,
483 		    O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, DEFFILEMODE)) == -1)
484 			err(1, "%s", cp->u.s->wfile);
485 		if (write(cp->u.s->wfd, ps, psl) != (ssize_t)psl ||
486 		    write(cp->u.s->wfd, "\n", 1) != 1)
487 			err(1, "%s", cp->u.s->wfile);
488 	}
489 	return (1);
490 }
491 
492 /*
493  * do_tr --
494  *	Perform translation ('y' command) in the pattern space.
495  */
496 static void
do_tr(struct s_tr * y)497 do_tr(struct s_tr *y)
498 {
499 	SPACE tmp;
500 	char c, *p;
501 	size_t clen, left;
502 	size_t i;
503 
504 	if (MB_CUR_MAX == 1) {
505 		/*
506 		 * Single-byte encoding: perform in-place translation
507 		 * of the pattern space.
508 		 */
509 		for (p = ps; p < &ps[psl]; p++)
510 			*p = (char)y->bytetab[(u_char)*p];
511 	} else {
512 		/*
513 		 * Multi-byte encoding: perform translation into the
514 		 * translation space, then swap the translation and
515 		 * pattern spaces.
516 		 */
517 		/* Clean translation space. */
518 		YS.len = 0;
519 		for (p = ps, left = psl; left > 0; p += clen, left -= clen) {
520 			if ((c = (char)y->bytetab[(u_char)*p]) != '\0') {
521 				cspace(&YS, &c, 1, APPEND);
522 				clen = 1;
523 				continue;
524 			}
525 			for (i = 0; i < y->nmultis; i++)
526 				if (left >= y->multis[i].fromlen &&
527 				    memcmp(p, y->multis[i].from,
528 				    y->multis[i].fromlen) == 0)
529 					break;
530 			if (i < y->nmultis) {
531 				cspace(&YS, y->multis[i].to,
532 				    y->multis[i].tolen, APPEND);
533 				clen = y->multis[i].fromlen;
534 			} else {
535 				cspace(&YS, p, 1, APPEND);
536 				clen = 1;
537 			}
538 		}
539 		/* Swap the translation space and the pattern space. */
540 		tmp = PS;
541 		PS = YS;
542 		psanl = tmp.append_newline;
543 		YS = tmp;
544 		YS.space = YS.back;
545 	}
546 }
547 
548 /*
549  * Flush append requests.  Always called before reading a line,
550  * therefore it also resets the substitution done (sdone) flag.
551  */
552 static void
flush_appends(void)553 flush_appends(void)
554 {
555 	FILE *f;
556 	size_t count, i;
557 	char buf[8 * 1024];
558 
559 	for (i = 0; i < appendx; i++)
560 		switch (appends[i].type) {
561 		case AP_STRING:
562 			fwrite(appends[i].s, sizeof(char), appends[i].len,
563 			    outfile);
564 			break;
565 		case AP_FILE:
566 			/*
567 			 * Read files probably shouldn't be cached.  Since
568 			 * it's not an error to read a non-existent file,
569 			 * it's possible that another program is interacting
570 			 * with the sed script through the filesystem.  It
571 			 * would be truly bizarre, but possible.  It's probably
572 			 * not that big a performance win, anyhow.
573 			 */
574 			if ((f = fopen(appends[i].s, "r")) == NULL)
575 				break;
576 			while ((count = fread(buf, sizeof(char), sizeof(buf), f)))
577 				(void)fwrite(buf, sizeof(char), count, outfile);
578 			(void)fclose(f);
579 			break;
580 		}
581 	if (ferror(outfile))
582 		errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
583 	appendx = 0;
584 	sdone = 0;
585 }
586 
587 static void
lputs(char * s,size_t len)588 lputs(char *s, size_t len)
589 {
590 	static const char escapes[] = "\\\a\b\f\r\t\v";
591 	int c;
592 	size_t col, width;
593 	const char *p;
594 #ifdef TIOCGWINSZ
595 	struct winsize win;
596 #endif
597 	static size_t termwidth = (size_t)-1;
598 	size_t clen, i;
599 	wchar_t wc;
600 	mbstate_t mbs;
601 
602 	if (outfile != stdout)
603 		termwidth = 60;
604 	if (termwidth == (size_t)-1) {
605 		if ((p = getenv("COLUMNS")) && *p != '\0')
606 			termwidth = (size_t)atoi(p);
607 #ifdef TIOCGWINSZ
608 		else if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &win) == 0 &&
609 		    win.ws_col > 0)
610 			termwidth = win.ws_col;
611 #endif
612 		else
613 			termwidth = 60;
614 	}
615 	if (termwidth == 0)
616 		termwidth = 1;
617 
618 	memset(&mbs, 0, sizeof(mbs));
619 	col = 0;
620 	while (len != 0) {
621 		clen = mbrtowc(&wc, s, len, &mbs);
622 		if (clen == 0)
623 			clen = 1;
624 		if (clen == (size_t)-1 || clen == (size_t)-2) {
625 			wc = (unsigned char)*s;
626 			clen = 1;
627 			memset(&mbs, 0, sizeof(mbs));
628 		}
629 		if (wc == '\n') {
630 			if (col + 1 >= termwidth)
631 				fprintf(outfile, "\\\n");
632 			fputc('$', outfile);
633 			fputc('\n', outfile);
634 			col = 0;
635 		} else if (iswprint(wc)) {
636 			width = (size_t)wcwidth(wc);
637 			if (col + width >= termwidth) {
638 				fprintf(outfile, "\\\n");
639 				col = 0;
640 			}
641 			fwrite(s, 1, clen, outfile);
642 			col += width;
643 		} else if (wc != L'\0' && (c = wctob(wc)) != EOF &&
644 		    (p = strchr(escapes, c)) != NULL) {
645 			if (col + 2 >= termwidth) {
646 				fprintf(outfile, "\\\n");
647 				col = 0;
648 			}
649 			fprintf(outfile, "\\%c", "\\abfrtv"[p - escapes]);
650 			col += 2;
651 		} else {
652 			if (col + 4 * clen >= termwidth) {
653 				fprintf(outfile, "\\\n");
654 				col = 0;
655 			}
656 			for (i = 0; i < clen; i++)
657 				fprintf(outfile, "\\%03o",
658 				    (int)(unsigned char)s[i]);
659 			col += 4 * clen;
660 		}
661 		s += clen;
662 		len -= clen;
663 	}
664 	if (col + 1 >= termwidth)
665 		fprintf(outfile, "\\\n");
666 	(void)fputc('$', outfile);
667 	(void)fputc('\n', outfile);
668 	if (ferror(outfile))
669 		errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
670 }
671 
672 static __inline int
regexec_e(regex_t * preg,const char * string,int eflags,int nomatch,size_t slen)673 regexec_e(regex_t *preg, const char *string, int eflags, int nomatch,
674 	size_t slen)
675 {
676 	int eval;
677 #ifndef REG_STARTEND
678 	char *buf;
679 #endif
680 
681 	if (preg == NULL) {
682 		if (defpreg == NULL)
683 			errx(1, "first RE may not be empty");
684 	} else
685 		defpreg = preg;
686 
687 	/* Set anchors */
688 #ifndef REG_STARTEND
689 	buf = xmalloc(slen + 1);
690 	(void)memcpy(buf, string, slen);
691 	buf[slen] = '\0';
692 	eval = regexec(defpreg, buf,
693 	    nomatch ? 0 : maxnsub + 1, match, eflags);
694 	free(buf);
695 #else
696 	match[0].rm_so = 0;
697 	match[0].rm_eo = (regoff_t)slen;
698 	eval = regexec(defpreg, string,
699 	    nomatch ? 0 : maxnsub + 1, match, eflags | REG_STARTEND);
700 #endif
701 	switch(eval) {
702 	case 0:
703 		return (1);
704 	case REG_NOMATCH:
705 		return (0);
706 	}
707 	errx(1, "RE error: %s", strregerror(eval, defpreg));
708 	/* NOTREACHED */
709 }
710 
711 /*
712  * regsub - perform substitutions after a regexp match
713  * Based on a routine by Henry Spencer
714  */
715 static void
regsub(SPACE * sp,char * string,char * src)716 regsub(SPACE *sp, char *string, char *src)
717 {
718 	size_t len;
719 	int no;
720 	char c, *dst;
721 
722 #define	NEEDSP(reqlen)							\
723 	/* XXX What is the +1 for? */					\
724 	if (sp->len + (reqlen) + 1 >= sp->blen) {			\
725 		sp->blen += (reqlen) + 1024;				\
726 		sp->space = sp->back = xrealloc(sp->back, sp->blen);	\
727 		dst = sp->space + sp->len;				\
728 	}
729 
730 	dst = sp->space + sp->len;
731 	while ((c = *src++) != '\0') {
732 		if (c == '&')
733 			no = 0;
734 		else if (c == '\\' && isdigit((unsigned char)*src))
735 			no = *src++ - '0';
736 		else
737 			no = -1;
738 		if (no < 0) {		/* Ordinary character. */
739 			if (c == '\\' && (*src == '\\' || *src == '&'))
740 				c = *src++;
741 			NEEDSP(1);
742 			*dst++ = c;
743 			++sp->len;
744 		} else if (match[no].rm_so != -1 && match[no].rm_eo != -1) {
745 			len = (size_t)(match[no].rm_eo - match[no].rm_so);
746 			NEEDSP(len);
747 			memmove(dst, string + match[no].rm_so, len);
748 			dst += len;
749 			sp->len += len;
750 		}
751 	}
752 	NEEDSP(1);
753 	*dst = '\0';
754 }
755 
756 /*
757  * cspace --
758  *	Concatenate space: append the source space to the destination space,
759  *	allocating new space as necessary.
760  */
761 void
cspace(SPACE * sp,const char * p,size_t len,enum e_spflag spflag)762 cspace(SPACE *sp, const char *p, size_t len, enum e_spflag spflag)
763 {
764 	size_t tlen;
765 
766 	/* Make sure SPACE has enough memory and ramp up quickly. */
767 	tlen = sp->len + len + 1;
768 	if (tlen > sp->blen) {
769 		sp->blen = tlen + 1024;
770 		sp->space = sp->back = xrealloc(sp->back, sp->blen);
771 	}
772 
773 	if (spflag == REPLACE)
774 		sp->len = 0;
775 
776 	memmove(sp->space + sp->len, p, len);
777 
778 	sp->space[sp->len += len] = '\0';
779 }
780 
781 /*
782  * Close all cached opened files and report any errors
783  */
784 void
cfclose(struct s_command * cp,struct s_command * end)785 cfclose(struct s_command *cp, struct s_command *end)
786 {
787 
788 	for (; cp != end; cp = cp->next)
789 		switch(cp->code) {
790 		case 's':
791 			if (cp->u.s->wfd != -1 && close(cp->u.s->wfd))
792 				err(1, "%s", cp->u.s->wfile);
793 			cp->u.s->wfd = -1;
794 			break;
795 		case 'w':
796 			if (cp->u.fd != -1 && close(cp->u.fd))
797 				err(1, "%s", cp->t);
798 			cp->u.fd = -1;
799 			break;
800 		case '{':
801 			cfclose(cp->u.c, cp->next);
802 			break;
803 		}
804 }
805