xref: /freebsd/usr.bin/sed/process.c (revision a0409676120c1e558d0ade943019934e0f15118d)
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 __FBSDID("$FreeBSD$");
38 
39 #ifndef lint
40 static const char sccsid[] = "@(#)process.c	8.6 (Berkeley) 4/20/94";
41 #endif
42 
43 #include <sys/types.h>
44 #include <sys/stat.h>
45 #include <sys/ioctl.h>
46 #include <sys/uio.h>
47 
48 #include <ctype.h>
49 #include <err.h>
50 #include <errno.h>
51 #include <fcntl.h>
52 #include <limits.h>
53 #include <regex.h>
54 #include <stdio.h>
55 #include <stdlib.h>
56 #include <string.h>
57 #include <unistd.h>
58 #include <wchar.h>
59 #include <wctype.h>
60 
61 #include "defs.h"
62 #include "extern.h"
63 
64 static SPACE HS, PS, SS, YS;
65 #define	pd		PS.deleted
66 #define	ps		PS.space
67 #define	psl		PS.len
68 #define	psanl		PS.append_newline
69 #define	hs		HS.space
70 #define	hsl		HS.len
71 
72 static inline int	 applies(struct s_command *);
73 static void		 do_tr(struct s_tr *);
74 static void		 flush_appends(void);
75 static void		 lputs(char *, size_t);
76 static int		 regexec_e(regex_t *, const char *, int, int, size_t,
77 			     size_t);
78 static void		 regsub(SPACE *, char *, char *);
79 static int		 substitute(struct s_command *);
80 
81 struct s_appends *appends;	/* Array of pointers to strings to append. */
82 static unsigned int appendx;	/* Index into appends array. */
83 unsigned int appendnum;		/* Size of appends array. */
84 
85 static int lastaddr;		/* Set by applies if last address of a range. */
86 static int sdone;		/* If any substitutes since last line input. */
87 				/* Iov structure for 'w' commands. */
88 static regex_t *defpreg;
89 size_t maxnsub;
90 regmatch_t *match;
91 
92 #define OUT() do {							\
93 	fwrite(ps, 1, psl, outfile);					\
94 	if (psanl) fputc('\n', outfile);				\
95 } while (0)
96 
97 void
98 process(void)
99 {
100 	struct s_command *cp;
101 	SPACE tspace;
102 	size_t oldpsl;
103 	char *p;
104 	int oldpsanl;
105 
106 	p = NULL;
107 	oldpsanl = oldpsl = 0;
108 
109 	for (linenum = 0; mf_fgets(&PS, REPLACE);) {
110 		pd = 0;
111 top:
112 		cp = prog;
113 redirect:
114 		while (cp != NULL) {
115 			if (!applies(cp)) {
116 				cp = cp->next;
117 				continue;
118 			}
119 			switch (cp->code) {
120 			case '{':
121 				cp = cp->u.c;
122 				goto redirect;
123 			case 'a':
124 				if (appendx >= appendnum)
125 					if ((appends = realloc(appends,
126 					    sizeof(struct s_appends) *
127 					    (appendnum *= 2))) == NULL)
128 						err(1, "realloc");
129 				appends[appendx].type = AP_STRING;
130 				appends[appendx].s = cp->t;
131 				appends[appendx].len = strlen(cp->t);
132 				appendx++;
133 				break;
134 			case 'b':
135 				cp = cp->u.c;
136 				goto redirect;
137 			case 'c':
138 				pd = 1;
139 				psl = 0;
140 				if (cp->a2 == NULL || lastaddr || lastline())
141 					(void)fprintf(outfile, "%s", cp->t);
142 				break;
143 			case 'd':
144 				pd = 1;
145 				goto new;
146 			case 'D':
147 				if (pd)
148 					goto new;
149 				if (psl == 0 ||
150 				    (p = memchr(ps, '\n', psl)) == NULL) {
151 					pd = 1;
152 					goto new;
153 				} else {
154 					psl -= (p + 1) - ps;
155 					memmove(ps, p + 1, psl);
156 					goto top;
157 				}
158 			case 'g':
159 				cspace(&PS, hs, hsl, REPLACE);
160 				break;
161 			case 'G':
162 				cspace(&PS, "\n", 1, APPEND);
163 				cspace(&PS, hs, hsl, APPEND);
164 				break;
165 			case 'h':
166 				cspace(&HS, ps, psl, REPLACE);
167 				break;
168 			case 'H':
169 				cspace(&HS, "\n", 1, APPEND);
170 				cspace(&HS, ps, psl, APPEND);
171 				break;
172 			case 'i':
173 				(void)fprintf(outfile, "%s", cp->t);
174 				break;
175 			case 'l':
176 				lputs(ps, psl);
177 				break;
178 			case 'n':
179 				if (!nflag && !pd)
180 					OUT();
181 				flush_appends();
182 				if (!mf_fgets(&PS, REPLACE))
183 					exit(0);
184 				pd = 0;
185 				break;
186 			case 'N':
187 				flush_appends();
188 				cspace(&PS, "\n", 1, APPEND);
189 				if (!mf_fgets(&PS, APPEND))
190 					exit(0);
191 				break;
192 			case 'p':
193 				if (pd)
194 					break;
195 				OUT();
196 				break;
197 			case 'P':
198 				if (pd)
199 					break;
200 				if ((p = memchr(ps, '\n', psl)) != NULL) {
201 					oldpsl = psl;
202 					oldpsanl = psanl;
203 					psl = p - ps;
204 					psanl = 1;
205 				}
206 				OUT();
207 				if (p != NULL) {
208 					psl = oldpsl;
209 					psanl = oldpsanl;
210 				}
211 				break;
212 			case 'q':
213 				if (inplace == NULL) {
214 					if (!nflag && !pd)
215 						OUT();
216 					flush_appends();
217 					exit(0);
218 				}
219 				quit = 1;
220 				break;
221 			case 'r':
222 				if (appendx >= appendnum)
223 					if ((appends = realloc(appends,
224 					    sizeof(struct s_appends) *
225 					    (appendnum *= 2))) == NULL)
226 						err(1, "realloc");
227 				appends[appendx].type = AP_FILE;
228 				appends[appendx].s = cp->t;
229 				appends[appendx].len = strlen(cp->t);
230 				appendx++;
231 				break;
232 			case 's':
233 				sdone |= substitute(cp);
234 				break;
235 			case 't':
236 				if (sdone) {
237 					sdone = 0;
238 					cp = cp->u.c;
239 					goto redirect;
240 				}
241 				break;
242 			case 'w':
243 				if (pd)
244 					break;
245 				if (cp->u.fd == -1 && (cp->u.fd = open(cp->t,
246 				    O_WRONLY|O_APPEND|O_CREAT|O_TRUNC,
247 				    DEFFILEMODE)) == -1)
248 					err(1, "%s", cp->t);
249 				if (write(cp->u.fd, ps, psl) != (ssize_t)psl ||
250 				    write(cp->u.fd, "\n", 1) != 1)
251 					err(1, "%s", cp->t);
252 				break;
253 			case 'x':
254 				/*
255 				 * If the hold space is null, make it empty
256 				 * but not null.  Otherwise the pattern space
257 				 * will become null after the swap, which is
258 				 * an abnormal condition.
259 				 */
260 				if (hs == NULL)
261 					cspace(&HS, "", 0, REPLACE);
262 				tspace = PS;
263 				PS = HS;
264 				psanl = tspace.append_newline;
265 				HS = tspace;
266 				break;
267 			case 'y':
268 				if (pd || psl == 0)
269 					break;
270 				do_tr(cp->u.y);
271 				break;
272 			case ':':
273 			case '}':
274 				break;
275 			case '=':
276 				(void)fprintf(outfile, "%lu\n", linenum);
277 			}
278 			cp = cp->next;
279 		} /* for all cp */
280 
281 new:		if (!nflag && !pd)
282 			OUT();
283 		flush_appends();
284 	} /* for all lines */
285 }
286 
287 /*
288  * TRUE if the address passed matches the current program state
289  * (lastline, linenumber, ps).
290  */
291 #define	MATCH(a)							\
292 	((a)->type == AT_RE ? regexec_e((a)->u.r, ps, 0, 1, 0, psl) :	\
293 	    (a)->type == AT_LINE ? linenum == (a)->u.l : lastline())
294 
295 /*
296  * Return TRUE if the command applies to the current line.  Sets the start
297  * line for process ranges.  Interprets the non-select (``!'') flag.
298  */
299 static inline int
300 applies(struct s_command *cp)
301 {
302 	int r;
303 
304 	lastaddr = 0;
305 	if (cp->a1 == NULL && cp->a2 == NULL)
306 		r = 1;
307 	else if (cp->a2)
308 		if (cp->startline > 0) {
309                         switch (cp->a2->type) {
310                         case AT_RELLINE:
311                                 if (linenum - cp->startline <= cp->a2->u.l)
312                                         r = 1;
313                                 else {
314 				        cp->startline = 0;
315 				        r = 0;
316                                 }
317                                 break;
318                         default:
319                                 if (MATCH(cp->a2)) {
320                                         cp->startline = 0;
321                                         lastaddr = 1;
322                                         r = 1;
323                                 } else if (cp->a2->type == AT_LINE &&
324                                             linenum > cp->a2->u.l) {
325                                         /*
326                                          * We missed the 2nd address due to a
327                                          * branch, so just close the range and
328                                          * return false.
329                                          */
330                                         cp->startline = 0;
331                                         r = 0;
332                                 } else
333                                         r = 1;
334                         }
335 		} else if (cp->a1 && MATCH(cp->a1)) {
336 			/*
337 			 * If the second address is a number less than or
338 			 * equal to the line number first selected, only
339 			 * one line shall be selected.
340 			 *	-- POSIX 1003.2
341 			 * Likewise if the relative second line address is zero.
342 			 */
343 			if ((cp->a2->type == AT_LINE &&
344 			    linenum >= cp->a2->u.l) ||
345 			    (cp->a2->type == AT_RELLINE && cp->a2->u.l == 0))
346 				lastaddr = 1;
347 			else {
348 				cp->startline = linenum;
349 			}
350 			r = 1;
351 		} else
352 			r = 0;
353 	else
354 		r = MATCH(cp->a1);
355 	return (cp->nonsel ? ! r : r);
356 }
357 
358 /*
359  * Reset the sed processor to its initial state.
360  */
361 void
362 resetstate(void)
363 {
364 	struct s_command *cp;
365 
366 	/*
367 	 * Reset all in-range markers.
368 	 */
369 	for (cp = prog; cp; cp = cp->code == '{' ? cp->u.c : cp->next)
370 		if (cp->a2)
371 			cp->startline = 0;
372 
373 	/*
374 	 * Clear out the hold space.
375 	 */
376 	cspace(&HS, "", 0, REPLACE);
377 }
378 
379 /*
380  * substitute --
381  *	Do substitutions in the pattern space.  Currently, we build a
382  *	copy of the new pattern space in the substitute space structure
383  *	and then swap them.
384  */
385 static int
386 substitute(struct s_command *cp)
387 {
388 	SPACE tspace;
389 	regex_t *re;
390 	regoff_t slen;
391 	int lastempty, n;
392 	regoff_t le = 0;
393 	char *s;
394 
395 	s = ps;
396 	re = cp->u.s->re;
397 	if (re == NULL) {
398 		if (defpreg != NULL && cp->u.s->maxbref > defpreg->re_nsub) {
399 			linenum = cp->u.s->linenum;
400 			errx(1, "%lu: %s: \\%u not defined in the RE",
401 					linenum, fname, cp->u.s->maxbref);
402 		}
403 	}
404 	if (!regexec_e(re, ps, 0, 0, 0, psl))
405 		return (0);
406 
407 	SS.len = 0;				/* Clean substitute space. */
408 	slen = psl;
409 	n = cp->u.s->n;
410 	lastempty = 1;
411 
412 	do {
413 		/* Copy the leading retained string. */
414 		if (n <= 1 && (match[0].rm_so > le))
415 			cspace(&SS, s, match[0].rm_so - le, APPEND);
416 
417 		/* Skip zero-length matches right after other matches. */
418 		if (lastempty || (match[0].rm_so - le) ||
419 		    match[0].rm_so != match[0].rm_eo) {
420 			if (n <= 1) {
421 				/* Want this match: append replacement. */
422 				regsub(&SS, ps, cp->u.s->new);
423 				if (n == 1)
424 					n = -1;
425 			} else {
426 				/* Want a later match: append original. */
427 				if (match[0].rm_eo - le)
428 					cspace(&SS, s, match[0].rm_eo - le,
429 					    APPEND);
430 				n--;
431 			}
432 		}
433 
434 		/* Move past this match. */
435 		s = ps + match[0].rm_eo;
436 		slen = psl - match[0].rm_eo;
437 		le = match[0].rm_eo;
438 
439 		/*
440 		 * After a zero-length match, advance one byte,
441 		 * and at the end of the line, terminate.
442 		 */
443 		if (match[0].rm_so == match[0].rm_eo) {
444 			if (*s == '\0' || *s == '\n')
445 				slen = -1;
446 			else
447 				slen--;
448 			if (*s != '\0') {
449 			 	cspace(&SS, s++, 1, APPEND);
450 				le++;
451 			}
452 			lastempty = 1;
453 		} else
454 			lastempty = 0;
455 
456 	} while (n >= 0 && slen >= 0 &&
457 	    regexec_e(re, ps, REG_NOTBOL, 0, le, psl));
458 
459 	/* Did not find the requested number of matches. */
460 	if (n > 0)
461 		return (0);
462 
463 	/* Copy the trailing retained string. */
464 	if (slen > 0)
465 		cspace(&SS, s, slen, APPEND);
466 
467 	/*
468 	 * Swap the substitute space and the pattern space, and make sure
469 	 * that any leftover pointers into stdio memory get lost.
470 	 */
471 	tspace = PS;
472 	PS = SS;
473 	psanl = tspace.append_newline;
474 	SS = tspace;
475 	SS.space = SS.back;
476 
477 	/* Handle the 'p' flag. */
478 	if (cp->u.s->p)
479 		OUT();
480 
481 	/* Handle the 'w' flag. */
482 	if (cp->u.s->wfile && !pd) {
483 		if (cp->u.s->wfd == -1 && (cp->u.s->wfd = open(cp->u.s->wfile,
484 		    O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, DEFFILEMODE)) == -1)
485 			err(1, "%s", cp->u.s->wfile);
486 		if (write(cp->u.s->wfd, ps, psl) != (ssize_t)psl ||
487 		    write(cp->u.s->wfd, "\n", 1) != 1)
488 			err(1, "%s", cp->u.s->wfile);
489 	}
490 	return (1);
491 }
492 
493 /*
494  * do_tr --
495  *	Perform translation ('y' command) in the pattern space.
496  */
497 static void
498 do_tr(struct s_tr *y)
499 {
500 	SPACE tmp;
501 	char c, *p;
502 	size_t clen, left;
503 	int i;
504 
505 	if (MB_CUR_MAX == 1) {
506 		/*
507 		 * Single-byte encoding: perform in-place translation
508 		 * of the pattern space.
509 		 */
510 		for (p = ps; p < &ps[psl]; p++)
511 			*p = y->bytetab[(u_char)*p];
512 	} else {
513 		/*
514 		 * Multi-byte encoding: perform translation into the
515 		 * translation space, then swap the translation and
516 		 * pattern spaces.
517 		 */
518 		/* Clean translation space. */
519 		YS.len = 0;
520 		for (p = ps, left = psl; left > 0; p += clen, left -= clen) {
521 			if ((c = y->bytetab[(u_char)*p]) != '\0') {
522 				cspace(&YS, &c, 1, APPEND);
523 				clen = 1;
524 				continue;
525 			}
526 			for (i = 0; i < y->nmultis; i++)
527 				if (left >= y->multis[i].fromlen &&
528 				    memcmp(p, y->multis[i].from,
529 				    y->multis[i].fromlen) == 0)
530 					break;
531 			if (i < y->nmultis) {
532 				cspace(&YS, y->multis[i].to,
533 				    y->multis[i].tolen, APPEND);
534 				clen = y->multis[i].fromlen;
535 			} else {
536 				cspace(&YS, p, 1, APPEND);
537 				clen = 1;
538 			}
539 		}
540 		/* Swap the translation space and the pattern space. */
541 		tmp = PS;
542 		PS = YS;
543 		psanl = tmp.append_newline;
544 		YS = tmp;
545 		YS.space = YS.back;
546 	}
547 }
548 
549 /*
550  * Flush append requests.  Always called before reading a line,
551  * therefore it also resets the substitution done (sdone) flag.
552  */
553 static void
554 flush_appends(void)
555 {
556 	FILE *f;
557 	unsigned int count, idx;
558 	char buf[8 * 1024];
559 
560 	for (idx = 0; idx < appendx; idx++)
561 		switch (appends[idx].type) {
562 		case AP_STRING:
563 			fwrite(appends[idx].s, sizeof(char), appends[idx].len,
564 			    outfile);
565 			break;
566 		case AP_FILE:
567 			/*
568 			 * Read files probably shouldn't be cached.  Since
569 			 * it's not an error to read a non-existent file,
570 			 * it's possible that another program is interacting
571 			 * with the sed script through the filesystem.  It
572 			 * would be truly bizarre, but possible.  It's probably
573 			 * not that big a performance win, anyhow.
574 			 */
575 			if ((f = fopen(appends[idx].s, "r")) == NULL)
576 				break;
577 			while ((count = fread(buf, sizeof(char), sizeof(buf), f)))
578 				(void)fwrite(buf, sizeof(char), count, outfile);
579 			(void)fclose(f);
580 			break;
581 		}
582 	if (ferror(outfile))
583 		errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
584 	appendx = sdone = 0;
585 }
586 
587 static void
588 lputs(char *s, size_t len)
589 {
590 	static const char escapes[] = "\\\a\b\f\r\t\v";
591 	int c, col, width;
592 	const char *p;
593 	struct winsize win;
594 	static int termwidth = -1;
595 	size_t clen, i;
596 	wchar_t wc;
597 	mbstate_t mbs;
598 
599 	if (outfile != stdout)
600 		termwidth = 60;
601 	if (termwidth == -1) {
602 		if ((p = getenv("COLUMNS")) && *p != '\0')
603 			termwidth = atoi(p);
604 		else if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &win) == 0 &&
605 		    win.ws_col > 0)
606 			termwidth = win.ws_col;
607 		else
608 			termwidth = 60;
609 	}
610 	if (termwidth <= 0)
611 		termwidth = 1;
612 
613 	memset(&mbs, 0, sizeof(mbs));
614 	col = 0;
615 	while (len != 0) {
616 		clen = mbrtowc(&wc, s, len, &mbs);
617 		if (clen == 0)
618 			clen = 1;
619 		if (clen == (size_t)-1 || clen == (size_t)-2) {
620 			wc = (unsigned char)*s;
621 			clen = 1;
622 			memset(&mbs, 0, sizeof(mbs));
623 		}
624 		if (wc == '\n') {
625 			if (col + 1 >= termwidth)
626 				fprintf(outfile, "\\\n");
627 			fputc('$', outfile);
628 			fputc('\n', outfile);
629 			col = 0;
630 		} else if (iswprint(wc)) {
631 			width = wcwidth(wc);
632 			if (col + width >= termwidth) {
633 				fprintf(outfile, "\\\n");
634 				col = 0;
635 			}
636 			fwrite(s, 1, clen, outfile);
637 			col += width;
638 		} else if (wc != L'\0' && (c = wctob(wc)) != EOF &&
639 		    (p = strchr(escapes, c)) != NULL) {
640 			if (col + 2 >= termwidth) {
641 				fprintf(outfile, "\\\n");
642 				col = 0;
643 			}
644 			fprintf(outfile, "\\%c", "\\abfrtv"[p - escapes]);
645 			col += 2;
646 		} else {
647 			if (col + 4 * clen >= (unsigned)termwidth) {
648 				fprintf(outfile, "\\\n");
649 				col = 0;
650 			}
651 			for (i = 0; i < clen; i++)
652 				fprintf(outfile, "\\%03o",
653 				    (int)(unsigned char)s[i]);
654 			col += 4 * clen;
655 		}
656 		s += clen;
657 		len -= clen;
658 	}
659 	if (col + 1 >= termwidth)
660 		fprintf(outfile, "\\\n");
661 	(void)fputc('$', outfile);
662 	(void)fputc('\n', outfile);
663 	if (ferror(outfile))
664 		errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
665 }
666 
667 static int
668 regexec_e(regex_t *preg, const char *string, int eflags, int nomatch,
669 	size_t start, size_t stop)
670 {
671 	int eval;
672 
673 	if (preg == NULL) {
674 		if (defpreg == NULL)
675 			errx(1, "first RE may not be empty");
676 	} else
677 		defpreg = preg;
678 
679 	/* Set anchors */
680 	match[0].rm_so = start;
681 	match[0].rm_eo = stop;
682 
683 	eval = regexec(defpreg, string,
684 	    nomatch ? 0 : maxnsub + 1, match, eflags | REG_STARTEND);
685 	switch(eval) {
686 	case 0:
687 		return (1);
688 	case REG_NOMATCH:
689 		return (0);
690 	}
691 	errx(1, "RE error: %s", strregerror(eval, defpreg));
692 	/* NOTREACHED */
693 }
694 
695 /*
696  * regsub - perform substitutions after a regexp match
697  * Based on a routine by Henry Spencer
698  */
699 static void
700 regsub(SPACE *sp, char *string, char *src)
701 {
702 	int len, no;
703 	char c, *dst;
704 
705 #define	NEEDSP(reqlen)							\
706 	/* XXX What is the +1 for? */					\
707 	if (sp->len + (reqlen) + 1 >= sp->blen) {			\
708 		sp->blen += (reqlen) + 1024;				\
709 		if ((sp->space = sp->back = realloc(sp->back, sp->blen)) \
710 		    == NULL)						\
711 			err(1, "realloc");				\
712 		dst = sp->space + sp->len;				\
713 	}
714 
715 	dst = sp->space + sp->len;
716 	while ((c = *src++) != '\0') {
717 		if (c == '&')
718 			no = 0;
719 		else if (c == '\\' && isdigit((unsigned char)*src))
720 			no = *src++ - '0';
721 		else
722 			no = -1;
723 		if (no < 0) {		/* Ordinary character. */
724 			if (c == '\\' && (*src == '\\' || *src == '&'))
725 				c = *src++;
726 			NEEDSP(1);
727 			*dst++ = c;
728 			++sp->len;
729 		} else if (match[no].rm_so != -1 && match[no].rm_eo != -1) {
730 			len = match[no].rm_eo - match[no].rm_so;
731 			NEEDSP(len);
732 			memmove(dst, string + match[no].rm_so, len);
733 			dst += len;
734 			sp->len += len;
735 		}
736 	}
737 	NEEDSP(1);
738 	*dst = '\0';
739 }
740 
741 /*
742  * cspace --
743  *	Concatenate space: append the source space to the destination space,
744  *	allocating new space as necessary.
745  */
746 void
747 cspace(SPACE *sp, const char *p, size_t len, enum e_spflag spflag)
748 {
749 	size_t tlen;
750 
751 	/* Make sure SPACE has enough memory and ramp up quickly. */
752 	tlen = sp->len + len + 1;
753 	if (tlen > sp->blen) {
754 		sp->blen = tlen + 1024;
755 		if ((sp->space = sp->back = realloc(sp->back, sp->blen)) ==
756 		    NULL)
757 			err(1, "realloc");
758 	}
759 
760 	if (spflag == REPLACE)
761 		sp->len = 0;
762 
763 	memmove(sp->space + sp->len, p, len);
764 
765 	sp->space[sp->len += len] = '\0';
766 }
767 
768 /*
769  * Close all cached opened files and report any errors
770  */
771 void
772 cfclose(struct s_command *cp, struct s_command *end)
773 {
774 
775 	for (; cp != end; cp = cp->next)
776 		switch(cp->code) {
777 		case 's':
778 			if (cp->u.s->wfd != -1 && close(cp->u.s->wfd))
779 				err(1, "%s", cp->u.s->wfile);
780 			cp->u.s->wfd = -1;
781 			break;
782 		case 'w':
783 			if (cp->u.fd != -1 && close(cp->u.fd))
784 				err(1, "%s", cp->t);
785 			cp->u.fd = -1;
786 			break;
787 		case '{':
788 			cfclose(cp->u.c, cp->next);
789 			break;
790 		}
791 }
792