xref: /freebsd/usr.bin/sed/process.c (revision d37eb51047221dc3322b34db1038ff3aa533883f)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
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 #include <sys/cdefs.h>
37 
38 #include <sys/types.h>
39 #include <sys/stat.h>
40 #include <sys/ioctl.h>
41 #include <sys/uio.h>
42 
43 #include <ctype.h>
44 #include <err.h>
45 #include <errno.h>
46 #include <fcntl.h>
47 #include <limits.h>
48 #include <regex.h>
49 #include <stdio.h>
50 #include <stdlib.h>
51 #include <string.h>
52 #include <unistd.h>
53 #include <wchar.h>
54 #include <wctype.h>
55 
56 #include "defs.h"
57 #include "extern.h"
58 
59 static SPACE HS, PS, SS, YS;
60 #define	pd		PS.deleted
61 #define	ps		PS.space
62 #define	psl		PS.len
63 #define	psanl		PS.append_newline
64 #define	hs		HS.space
65 #define	hsl		HS.len
66 
67 static inline int	 applies(struct s_command *);
68 static void		 do_tr(struct s_tr *);
69 static void		 flush_appends(void);
70 static void		 lputs(char *, size_t);
71 static int		 regexec_e(regex_t *, const char *, int, int, size_t,
72 			     size_t);
73 static void		 regsub(SPACE *, char *, char *);
74 static int		 substitute(struct s_command *);
75 
76 struct s_appends *appends;	/* Array of pointers to strings to append. */
77 static unsigned int appendx;	/* Index into appends array. */
78 unsigned int appendnum;		/* Size of appends array. */
79 
80 static int lastaddr;		/* Set by applies if last address of a range. */
81 static int sdone;		/* If any substitutes since last line input. */
82 				/* Iov structure for 'w' commands. */
83 static regex_t *defpreg;
84 size_t maxnsub;
85 regmatch_t *match;
86 
87 #define OUT() do {							\
88 	fwrite(ps, 1, psl, outfile);					\
89 	if (psanl) fputc('\n', outfile);				\
90 } while (0)
91 
92 void
93 process(void)
94 {
95 	struct s_command *cp;
96 	SPACE tspace;
97 	size_t oldpsl;
98 	char *p;
99 	int oldpsanl;
100 
101 	p = NULL;
102 	oldpsanl = oldpsl = 0;
103 
104 	for (linenum = 0; mf_fgets(&PS, REPLACE);) {
105 		pd = 0;
106 top:
107 		cp = prog;
108 redirect:
109 		while (cp != NULL) {
110 			if (!applies(cp)) {
111 				cp = cp->next;
112 				continue;
113 			}
114 			switch (cp->code) {
115 			case '{':
116 				cp = cp->u.c;
117 				goto redirect;
118 			case 'a':
119 				if (appendx >= appendnum)
120 					if ((appends = realloc(appends,
121 					    sizeof(struct s_appends) *
122 					    (appendnum *= 2))) == NULL)
123 						err(1, "realloc");
124 				appends[appendx].type = AP_STRING;
125 				appends[appendx].s = cp->t;
126 				appends[appendx].len = strlen(cp->t);
127 				appendx++;
128 				break;
129 			case 'b':
130 				cp = cp->u.c;
131 				goto redirect;
132 			case 'c':
133 				pd = 1;
134 				psl = 0;
135 				if (cp->a2 == NULL || lastaddr || lastline())
136 					(void)fprintf(outfile, "%s", cp->t);
137 				break;
138 			case 'd':
139 				pd = 1;
140 				goto new;
141 			case 'D':
142 				if (pd)
143 					goto new;
144 				if (psl == 0 ||
145 				    (p = memchr(ps, '\n', psl)) == NULL) {
146 					pd = 1;
147 					goto new;
148 				} else {
149 					psl -= (p + 1) - ps;
150 					memmove(ps, p + 1, psl);
151 					goto top;
152 				}
153 			case 'g':
154 				cspace(&PS, hs, hsl, REPLACE);
155 				break;
156 			case 'G':
157 				cspace(&PS, "\n", 1, APPEND);
158 				cspace(&PS, hs, hsl, APPEND);
159 				break;
160 			case 'h':
161 				cspace(&HS, ps, psl, REPLACE);
162 				break;
163 			case 'H':
164 				cspace(&HS, "\n", 1, APPEND);
165 				cspace(&HS, ps, psl, APPEND);
166 				break;
167 			case 'i':
168 				(void)fprintf(outfile, "%s", cp->t);
169 				break;
170 			case 'l':
171 				lputs(ps, psl);
172 				break;
173 			case 'n':
174 				if (!nflag && !pd)
175 					OUT();
176 				flush_appends();
177 				if (!mf_fgets(&PS, REPLACE))
178 					exit(0);
179 				pd = 0;
180 				break;
181 			case 'N':
182 				flush_appends();
183 				cspace(&PS, "\n", 1, APPEND);
184 				if (!mf_fgets(&PS, APPEND))
185 					exit(0);
186 				break;
187 			case 'p':
188 				if (pd)
189 					break;
190 				OUT();
191 				break;
192 			case 'P':
193 				if (pd)
194 					break;
195 				if ((p = memchr(ps, '\n', psl)) != NULL) {
196 					oldpsl = psl;
197 					oldpsanl = psanl;
198 					psl = p - ps;
199 					psanl = 1;
200 				}
201 				OUT();
202 				if (p != NULL) {
203 					psl = oldpsl;
204 					psanl = oldpsanl;
205 				}
206 				break;
207 			case 'q':
208 				if (inplace == NULL) {
209 					if (!nflag && !pd)
210 						OUT();
211 					flush_appends();
212 					exit(0);
213 				}
214 				quit = 1;
215 				break;
216 			case 'r':
217 				if (appendx >= appendnum)
218 					if ((appends = realloc(appends,
219 					    sizeof(struct s_appends) *
220 					    (appendnum *= 2))) == NULL)
221 						err(1, "realloc");
222 				appends[appendx].type = AP_FILE;
223 				appends[appendx].s = cp->t;
224 				appends[appendx].len = strlen(cp->t);
225 				appendx++;
226 				break;
227 			case 's':
228 				sdone |= substitute(cp);
229 				break;
230 			case 't':
231 				if (sdone) {
232 					sdone = 0;
233 					cp = cp->u.c;
234 					goto redirect;
235 				}
236 				break;
237 			case 'w':
238 				if (pd)
239 					break;
240 				if (cp->u.fd == -1 && (cp->u.fd = open(cp->t,
241 				    O_WRONLY|O_APPEND|O_CREAT|O_TRUNC,
242 				    DEFFILEMODE)) == -1)
243 					err(1, "%s", cp->t);
244 				if (write(cp->u.fd, ps, psl) != (ssize_t)psl ||
245 				    write(cp->u.fd, "\n", 1) != 1)
246 					err(1, "%s", cp->t);
247 				break;
248 			case 'x':
249 				/*
250 				 * If the hold space is null, make it empty
251 				 * but not null.  Otherwise the pattern space
252 				 * will become null after the swap, which is
253 				 * an abnormal condition.
254 				 */
255 				if (hs == NULL)
256 					cspace(&HS, "", 0, REPLACE);
257 				tspace = PS;
258 				PS = HS;
259 				psanl = tspace.append_newline;
260 				HS = tspace;
261 				break;
262 			case 'y':
263 				if (pd || psl == 0)
264 					break;
265 				do_tr(cp->u.y);
266 				break;
267 			case ':':
268 			case '}':
269 				break;
270 			case '=':
271 				(void)fprintf(outfile, "%lu\n", linenum);
272 			}
273 			cp = cp->next;
274 		} /* for all cp */
275 
276 new:		if (!nflag && !pd)
277 			OUT();
278 		flush_appends();
279 	} /* for all lines */
280 }
281 
282 /*
283  * TRUE if the address passed matches the current program state
284  * (lastline, linenumber, ps).
285  */
286 #define	MATCH(a)							\
287 	((a)->type == AT_RE ? regexec_e((a)->u.r, ps, 0, 1, 0, psl) :	\
288 	    (a)->type == AT_LINE ? linenum == (a)->u.l : lastline())
289 
290 /*
291  * Return TRUE if the command applies to the current line.  Sets the start
292  * line for process ranges.  Interprets the non-select (``!'') flag.
293  */
294 static inline int
295 applies(struct s_command *cp)
296 {
297 	int r;
298 
299 	lastaddr = 0;
300 	if (cp->a1 == NULL && cp->a2 == NULL)
301 		r = 1;
302 	else if (cp->a2)
303 		if (cp->startline > 0) {
304                         switch (cp->a2->type) {
305                         case AT_RELLINE:
306                                 if (linenum - cp->startline <= cp->a2->u.l)
307                                         r = 1;
308                                 else {
309 				        cp->startline = 0;
310 				        r = 0;
311                                 }
312                                 break;
313                         default:
314                                 if (MATCH(cp->a2)) {
315                                         cp->startline = 0;
316                                         lastaddr = 1;
317                                         r = 1;
318                                 } else if (cp->a2->type == AT_LINE &&
319                                             linenum > cp->a2->u.l) {
320                                         /*
321                                          * We missed the 2nd address due to a
322                                          * branch, so just close the range and
323                                          * return false.
324                                          */
325                                         cp->startline = 0;
326                                         r = 0;
327                                 } else
328                                         r = 1;
329                         }
330 		} else if (cp->a1 && MATCH(cp->a1)) {
331 			/*
332 			 * If the second address is a number less than or
333 			 * equal to the line number first selected, only
334 			 * one line shall be selected.
335 			 *	-- POSIX 1003.2
336 			 * Likewise if the relative second line address is zero.
337 			 */
338 			if ((cp->a2->type == AT_LINE &&
339 			    linenum >= cp->a2->u.l) ||
340 			    (cp->a2->type == AT_RELLINE && cp->a2->u.l == 0))
341 				lastaddr = 1;
342 			else {
343 				cp->startline = linenum;
344 			}
345 			r = 1;
346 		} else
347 			r = 0;
348 	else
349 		r = MATCH(cp->a1);
350 	return (cp->nonsel ? ! r : r);
351 }
352 
353 /*
354  * Reset the sed processor to its initial state.
355  */
356 void
357 resetstate(void)
358 {
359 	struct s_command *cp;
360 
361 	/*
362 	 * Reset all in-range markers.
363 	 */
364 	for (cp = prog; cp; cp = cp->code == '{' ? cp->u.c : cp->next)
365 		if (cp->a2)
366 			cp->startline = 0;
367 
368 	/*
369 	 * Clear out the hold space.
370 	 */
371 	cspace(&HS, "", 0, REPLACE);
372 }
373 
374 /*
375  * substitute --
376  *	Do substitutions in the pattern space.  Currently, we build a
377  *	copy of the new pattern space in the substitute space structure
378  *	and then swap them.
379  */
380 static int
381 substitute(struct s_command *cp)
382 {
383 	SPACE tspace;
384 	regex_t *re;
385 	regoff_t slen;
386 	int lastempty, n;
387 	regoff_t le = 0;
388 	char *s;
389 
390 	s = ps;
391 	re = cp->u.s->re;
392 	if (re == NULL) {
393 		if (defpreg != NULL && cp->u.s->maxbref > defpreg->re_nsub) {
394 			linenum = cp->u.s->linenum;
395 			errx(1, "%lu: %s: \\%u not defined in the RE",
396 					linenum, fname, cp->u.s->maxbref);
397 		}
398 	}
399 	if (!regexec_e(re, ps, 0, 0, 0, psl))
400 		return (0);
401 
402 	SS.len = 0;				/* Clean substitute space. */
403 	slen = psl;
404 	n = cp->u.s->n;
405 	lastempty = 1;
406 
407 	do {
408 		/* Copy the leading retained string. */
409 		if (n <= 1 && (match[0].rm_so > le))
410 			cspace(&SS, s, match[0].rm_so - le, APPEND);
411 
412 		/* Skip zero-length matches right after other matches. */
413 		if (lastempty || (match[0].rm_so - le) ||
414 		    match[0].rm_so != match[0].rm_eo) {
415 			if (n <= 1) {
416 				/* Want this match: append replacement. */
417 				regsub(&SS, ps, cp->u.s->new);
418 				if (n == 1)
419 					n = -1;
420 			} else {
421 				/* Want a later match: append original. */
422 				if (match[0].rm_eo - le)
423 					cspace(&SS, s, match[0].rm_eo - le,
424 					    APPEND);
425 				n--;
426 			}
427 		}
428 
429 		/* Move past this match. */
430 		s = ps + match[0].rm_eo;
431 		slen = psl - match[0].rm_eo;
432 		le = match[0].rm_eo;
433 
434 		/*
435 		 * After a zero-length match, advance one byte,
436 		 * and at the end of the line, terminate.
437 		 */
438 		if (match[0].rm_so == match[0].rm_eo) {
439 			if (*s == '\0' || *s == '\n')
440 				slen = -1;
441 			else
442 				slen--;
443 			if (*s != '\0') {
444 			 	cspace(&SS, s++, 1, APPEND);
445 				le++;
446 			}
447 			lastempty = 1;
448 		} else
449 			lastempty = 0;
450 
451 	} while (n >= 0 && slen >= 0 &&
452 	    regexec_e(re, ps, REG_NOTBOL, 0, le, psl));
453 
454 	/* Did not find the requested number of matches. */
455 	if (n > 0)
456 		return (0);
457 
458 	/* Copy the trailing retained string. */
459 	if (slen > 0)
460 		cspace(&SS, s, slen, APPEND);
461 
462 	/*
463 	 * Swap the substitute space and the pattern space, and make sure
464 	 * that any leftover pointers into stdio memory get lost.
465 	 */
466 	tspace = PS;
467 	PS = SS;
468 	psanl = tspace.append_newline;
469 	SS = tspace;
470 	SS.space = SS.back;
471 
472 	/* Handle the 'p' flag. */
473 	if (cp->u.s->p)
474 		OUT();
475 
476 	/* Handle the 'w' flag. */
477 	if (cp->u.s->wfile && !pd) {
478 		if (cp->u.s->wfd == -1 && (cp->u.s->wfd = open(cp->u.s->wfile,
479 		    O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, DEFFILEMODE)) == -1)
480 			err(1, "%s", cp->u.s->wfile);
481 		if (write(cp->u.s->wfd, ps, psl) != (ssize_t)psl ||
482 		    write(cp->u.s->wfd, "\n", 1) != 1)
483 			err(1, "%s", cp->u.s->wfile);
484 	}
485 	return (1);
486 }
487 
488 /*
489  * do_tr --
490  *	Perform translation ('y' command) in the pattern space.
491  */
492 static void
493 do_tr(struct s_tr *y)
494 {
495 	SPACE tmp;
496 	char c, *p;
497 	size_t clen, left;
498 	int i;
499 
500 	if (MB_CUR_MAX == 1) {
501 		/*
502 		 * Single-byte encoding: perform in-place translation
503 		 * of the pattern space.
504 		 */
505 		for (p = ps; p < &ps[psl]; p++)
506 			*p = y->bytetab[(u_char)*p];
507 	} else {
508 		/*
509 		 * Multi-byte encoding: perform translation into the
510 		 * translation space, then swap the translation and
511 		 * pattern spaces.
512 		 */
513 		/* Clean translation space. */
514 		YS.len = 0;
515 		for (p = ps, left = psl; left > 0; p += clen, left -= clen) {
516 			if ((c = y->bytetab[(u_char)*p]) != '\0') {
517 				cspace(&YS, &c, 1, APPEND);
518 				clen = 1;
519 				continue;
520 			}
521 			for (i = 0; i < y->nmultis; i++)
522 				if (left >= y->multis[i].fromlen &&
523 				    memcmp(p, y->multis[i].from,
524 				    y->multis[i].fromlen) == 0)
525 					break;
526 			if (i < y->nmultis) {
527 				cspace(&YS, y->multis[i].to,
528 				    y->multis[i].tolen, APPEND);
529 				clen = y->multis[i].fromlen;
530 			} else {
531 				cspace(&YS, p, 1, APPEND);
532 				clen = 1;
533 			}
534 		}
535 		/* Swap the translation space and the pattern space. */
536 		tmp = PS;
537 		PS = YS;
538 		psanl = tmp.append_newline;
539 		YS = tmp;
540 		YS.space = YS.back;
541 	}
542 }
543 
544 /*
545  * Flush append requests.  Always called before reading a line,
546  * therefore it also resets the substitution done (sdone) flag.
547  */
548 static void
549 flush_appends(void)
550 {
551 	FILE *f;
552 	unsigned int count, idx;
553 	char buf[8 * 1024];
554 
555 	for (idx = 0; idx < appendx; idx++)
556 		switch (appends[idx].type) {
557 		case AP_STRING:
558 			fwrite(appends[idx].s, sizeof(char), appends[idx].len,
559 			    outfile);
560 			break;
561 		case AP_FILE:
562 			/*
563 			 * Read files probably shouldn't be cached.  Since
564 			 * it's not an error to read a non-existent file,
565 			 * it's possible that another program is interacting
566 			 * with the sed script through the filesystem.  It
567 			 * would be truly bizarre, but possible.  It's probably
568 			 * not that big a performance win, anyhow.
569 			 */
570 			if ((f = fopen(appends[idx].s, "r")) == NULL)
571 				break;
572 			while ((count = fread(buf, sizeof(char), sizeof(buf), f)))
573 				(void)fwrite(buf, sizeof(char), count, outfile);
574 			(void)fclose(f);
575 			break;
576 		}
577 	if (ferror(outfile))
578 		errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
579 	appendx = sdone = 0;
580 }
581 
582 static void
583 lputs(char *s, size_t len)
584 {
585 	static const char escapes[] = "\\\a\b\f\r\t\v";
586 	int c, col, width;
587 	const char *p;
588 	struct winsize win;
589 	static int termwidth = -1;
590 	size_t clen, i;
591 	wchar_t wc;
592 	mbstate_t mbs;
593 
594 	if (outfile != stdout)
595 		termwidth = 60;
596 	if (termwidth == -1) {
597 		if ((p = getenv("COLUMNS")) && *p != '\0')
598 			termwidth = atoi(p);
599 		else if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &win) == 0 &&
600 		    win.ws_col > 0)
601 			termwidth = win.ws_col;
602 		else
603 			termwidth = 60;
604 	}
605 	if (termwidth <= 0)
606 		termwidth = 1;
607 
608 	memset(&mbs, 0, sizeof(mbs));
609 	col = 0;
610 	while (len != 0) {
611 		clen = mbrtowc(&wc, s, len, &mbs);
612 		if (clen == 0)
613 			clen = 1;
614 		if (clen == (size_t)-1 || clen == (size_t)-2) {
615 			wc = (unsigned char)*s;
616 			clen = 1;
617 			memset(&mbs, 0, sizeof(mbs));
618 		}
619 		if (wc == '\n') {
620 			if (col + 1 >= termwidth)
621 				fprintf(outfile, "\\\n");
622 			fputc('$', outfile);
623 			fputc('\n', outfile);
624 			col = 0;
625 		} else if (iswprint(wc)) {
626 			width = wcwidth(wc);
627 			if (col + width >= termwidth) {
628 				fprintf(outfile, "\\\n");
629 				col = 0;
630 			}
631 			fwrite(s, 1, clen, outfile);
632 			col += width;
633 		} else if (wc != L'\0' && (c = wctob(wc)) != EOF &&
634 		    (p = strchr(escapes, c)) != NULL) {
635 			if (col + 2 >= termwidth) {
636 				fprintf(outfile, "\\\n");
637 				col = 0;
638 			}
639 			fprintf(outfile, "\\%c", "\\abfrtv"[p - escapes]);
640 			col += 2;
641 		} else {
642 			if (col + 4 * clen >= (unsigned)termwidth) {
643 				fprintf(outfile, "\\\n");
644 				col = 0;
645 			}
646 			for (i = 0; i < clen; i++)
647 				fprintf(outfile, "\\%03o",
648 				    (int)(unsigned char)s[i]);
649 			col += 4 * clen;
650 		}
651 		s += clen;
652 		len -= clen;
653 	}
654 	if (col + 1 >= termwidth)
655 		fprintf(outfile, "\\\n");
656 	(void)fputc('$', outfile);
657 	(void)fputc('\n', outfile);
658 	if (ferror(outfile))
659 		errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
660 }
661 
662 static int
663 regexec_e(regex_t *preg, const char *string, int eflags, int nomatch,
664 	size_t start, size_t stop)
665 {
666 	int eval;
667 
668 	if (preg == NULL) {
669 		if (defpreg == NULL)
670 			errx(1, "first RE may not be empty");
671 	} else
672 		defpreg = preg;
673 
674 	/* Set anchors */
675 	match[0].rm_so = start;
676 	match[0].rm_eo = stop;
677 
678 	eval = regexec(defpreg, string,
679 	    nomatch ? 0 : maxnsub + 1, match, eflags | REG_STARTEND);
680 	switch(eval) {
681 	case 0:
682 		return (1);
683 	case REG_NOMATCH:
684 		return (0);
685 	}
686 	errx(1, "RE error: %s", strregerror(eval, defpreg));
687 	/* NOTREACHED */
688 }
689 
690 /*
691  * regsub - perform substitutions after a regexp match
692  * Based on a routine by Henry Spencer
693  */
694 static void
695 regsub(SPACE *sp, char *string, char *src)
696 {
697 	int len, no;
698 	char c, *dst;
699 
700 #define	NEEDSP(reqlen)							\
701 	/* XXX What is the +1 for? */					\
702 	if (sp->len + (reqlen) + 1 >= sp->blen) {			\
703 		sp->blen += (reqlen) + 1024;				\
704 		if ((sp->space = sp->back = realloc(sp->back, sp->blen)) \
705 		    == NULL)						\
706 			err(1, "realloc");				\
707 		dst = sp->space + sp->len;				\
708 	}
709 
710 	dst = sp->space + sp->len;
711 	while ((c = *src++) != '\0') {
712 		if (c == '&')
713 			no = 0;
714 		else if (c == '\\' && isdigit((unsigned char)*src))
715 			no = *src++ - '0';
716 		else
717 			no = -1;
718 		if (no < 0) {		/* Ordinary character. */
719 			if (c == '\\' && (*src == '\\' || *src == '&'))
720 				c = *src++;
721 			NEEDSP(1);
722 			*dst++ = c;
723 			++sp->len;
724 		} else if (match[no].rm_so != -1 && match[no].rm_eo != -1) {
725 			len = match[no].rm_eo - match[no].rm_so;
726 			NEEDSP(len);
727 			memmove(dst, string + match[no].rm_so, len);
728 			dst += len;
729 			sp->len += len;
730 		}
731 	}
732 	NEEDSP(1);
733 	*dst = '\0';
734 }
735 
736 /*
737  * cspace --
738  *	Concatenate space: append the source space to the destination space,
739  *	allocating new space as necessary.
740  */
741 void
742 cspace(SPACE *sp, const char *p, size_t len, enum e_spflag spflag)
743 {
744 	size_t tlen;
745 
746 	/* Make sure SPACE has enough memory and ramp up quickly. */
747 	tlen = sp->len + len + 1;
748 	if (tlen > sp->blen) {
749 		sp->blen = tlen + 1024;
750 		if ((sp->space = sp->back = realloc(sp->back, sp->blen)) ==
751 		    NULL)
752 			err(1, "realloc");
753 	}
754 
755 	if (spflag == REPLACE)
756 		sp->len = 0;
757 
758 	memmove(sp->space + sp->len, p, len);
759 
760 	sp->space[sp->len += len] = '\0';
761 }
762 
763 /*
764  * Close all cached opened files and report any errors
765  */
766 void
767 cfclose(struct s_command *cp, struct s_command *end)
768 {
769 
770 	for (; cp != end; cp = cp->next)
771 		switch(cp->code) {
772 		case 's':
773 			if (cp->u.s->wfd != -1 && close(cp->u.s->wfd))
774 				err(1, "%s", cp->u.s->wfile);
775 			cp->u.s->wfd = -1;
776 			break;
777 		case 'w':
778 			if (cp->u.fd != -1 && close(cp->u.fd))
779 				err(1, "%s", cp->t);
780 			cp->u.fd = -1;
781 			break;
782 		case '{':
783 			cfclose(cp->u.c, cp->next);
784 			break;
785 		}
786 }
787