xref: /netbsd-src/usr.bin/sed/process.c (revision b7b7574d3bf8eeb51a1fa3977b59142ec6434a55)
1 /*	$NetBSD: process.c,v 1.45 2014/06/26 02:14:32 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 1.45 2014/06/26 02:14:32 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	hs		HS.space
76 #define	hsl		HS.len
77 
78 static __inline int	 applies(struct s_command *);
79 static void		 do_tr(struct s_tr *);
80 static void		 flush_appends(void);
81 static void		 lputs(char *, size_t);
82 static __inline int	 regexec_e(regex_t *, const char *, int, int, size_t);
83 static void		 regsub(SPACE *, char *, char *);
84 static int		 substitute(struct s_command *);
85 
86 struct s_appends *appends;	/* Array of pointers to strings to append. */
87 static size_t appendx;		/* Index into appends array. */
88 size_t appendnum;			/* Size of appends array. */
89 
90 static int lastaddr;		/* Set by applies if last address of a range. */
91 static int sdone;		/* If any substitutes since last line input. */
92 				/* Iov structure for 'w' commands. */
93 static regex_t *defpreg;
94 size_t maxnsub;
95 regmatch_t *match;
96 
97 #define OUT() do {fwrite(ps, 1, psl, outfile); fputc('\n', outfile);} while (0)
98 
99 void
100 process(void)
101 {
102 	struct s_command *cp;
103 	SPACE tspace;
104 	size_t oldpsl = 0;
105 	char *p;
106 
107 	p = NULL;
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 					appends = xrealloc(appends,
126 					    sizeof(struct s_appends) *
127 					    (appendnum *= 2));
128 				appends[appendx].type = AP_STRING;
129 				appends[appendx].s = cp->t;
130 				appends[appendx].len = strlen(cp->t);
131 				appendx++;
132 				break;
133 			case 'b':
134 				cp = cp->u.c;
135 				goto redirect;
136 			case 'c':
137 				pd = 1;
138 				psl = 0;
139 				if (cp->a2 == NULL || lastaddr || lastline())
140 					(void)fprintf(outfile, "%s", cp->t);
141 				goto new;
142 			case 'd':
143 				pd = 1;
144 				goto new;
145 			case 'D':
146 				if (pd)
147 					goto new;
148 				if (psl == 0 ||
149 				    (p = memchr(ps, '\n', psl - 1)) == NULL) {
150 					pd = 1;
151 					goto new;
152 				} else {
153 					psl -= (size_t)((p + 1) - ps);
154 					memmove(ps, p + 1, psl);
155 					goto top;
156 				}
157 			case 'g':
158 				cspace(&PS, hs, hsl, REPLACE);
159 				break;
160 			case 'G':
161 				cspace(&PS, "\n", 1, APPEND);
162 				cspace(&PS, hs, hsl, APPEND);
163 				break;
164 			case 'h':
165 				cspace(&HS, ps, psl, REPLACE);
166 				break;
167 			case 'H':
168 				cspace(&HS, "\n", 1, APPEND);
169 				cspace(&HS, ps, psl, APPEND);
170 				break;
171 			case 'i':
172 				(void)fprintf(outfile, "%s", cp->t);
173 				break;
174 			case 'l':
175 				lputs(ps, psl);
176 				break;
177 			case 'n':
178 				if (!nflag && !pd)
179 					OUT();
180 				flush_appends();
181 				if (!mf_fgets(&PS, REPLACE))
182 					exit(0);
183 				pd = 0;
184 				break;
185 			case 'N':
186 				flush_appends();
187 				cspace(&PS, "\n", 1, APPEND);
188 				if (!mf_fgets(&PS, APPEND))
189 					exit(0);
190 				break;
191 			case 'p':
192 				if (pd)
193 					break;
194 				OUT();
195 				break;
196 			case 'P':
197 				if (pd)
198 					break;
199 				if ((p = memchr(ps, '\n', psl - 1)) != NULL) {
200 					oldpsl = psl;
201 					psl = (size_t)(p - ps);
202 				}
203 				OUT();
204 				if (p != NULL)
205 					psl = oldpsl;
206 				break;
207 			case 'q':
208 				if (!nflag && !pd)
209 					OUT();
210 				flush_appends();
211 				exit(0);
212 			case 'r':
213 				if (appendx >= appendnum)
214 					appends = xrealloc(appends,
215 					    sizeof(struct s_appends) *
216 					    (appendnum *= 2));
217 				appends[appendx].type = AP_FILE;
218 				appends[appendx].s = cp->t;
219 				appends[appendx].len = strlen(cp->t);
220 				appendx++;
221 				break;
222 			case 's':
223 				sdone |= substitute(cp);
224 				break;
225 			case 't':
226 				if (sdone) {
227 					sdone = 0;
228 					cp = cp->u.c;
229 					goto redirect;
230 				}
231 				break;
232 			case 'w':
233 				if (pd)
234 					break;
235 				if (cp->u.fd == -1 && (cp->u.fd = open(cp->t,
236 				    O_WRONLY|O_APPEND|O_CREAT|O_TRUNC,
237 				    DEFFILEMODE)) == -1)
238 					err(1, "%s", cp->t);
239 				if (write(cp->u.fd, ps, psl) != (ssize_t)psl ||
240 				    write(cp->u.fd, "\n", 1) != 1)
241 					err(1, "%s", cp->t);
242 				break;
243 			case 'x':
244 				/*
245 				 * If the hold space is null, make it empty
246 				 * but not null.  Otherwise the pattern space
247 				 * will become null after the swap, which is
248 				 * an abnormal condition.
249 				 */
250 				if (hs == NULL)
251 					cspace(&HS, "", 0, REPLACE);
252 				tspace = PS;
253 				PS = HS;
254 				HS = tspace;
255 				break;
256 			case 'y':
257 				if (pd || psl == 0)
258 					break;
259 				do_tr(cp->u.y);
260 				break;
261 			case ':':
262 			case '}':
263 				break;
264 			case '=':
265 				(void)fprintf(outfile, "%lu\n", linenum);
266 			}
267 			cp = cp->next;
268 		} /* for all cp */
269 
270 new:		if (!nflag && !pd)
271 			OUT();
272 		flush_appends();
273 	} /* for all lines */
274 }
275 
276 /*
277  * TRUE if the address passed matches the current program state
278  * (lastline, linenumber, ps).
279  */
280 #define	MATCH(a)							\
281 	((a)->type == AT_RE ? regexec_e((a)->u.r, ps, 0, 1, psl) :	\
282 	    (a)->type == AT_LINE ? linenum == (a)->u.l : lastline())
283 
284 /*
285  * Return TRUE if the command applies to the current line.  Sets the start
286  * line for process ranges.  Interprets the non-select (``!'') flag.
287  */
288 static __inline int
289 applies(struct s_command *cp)
290 {
291 	int r;
292 
293 	lastaddr = 0;
294 	if (cp->a1 == NULL && cp->a2 == NULL)
295 		r = 1;
296 	else if (cp->a2)
297 		if (cp->startline > 0) {
298 			if (MATCH(cp->a2)) {
299 				cp->startline = 0;
300 				lastaddr = 1;
301 				r = 1;
302 			} else if (linenum - cp->startline <= cp->a2->u.l)
303 				r = 1;
304 			else if ((cp->a2->type == AT_LINE &&
305 				   linenum > cp->a2->u.l) ||
306 				   (cp->a2->type == AT_RELLINE &&
307 				   linenum - cp->startline > cp->a2->u.l)) {
308 				/*
309 				 * We missed the 2nd address due to a branch,
310 				 * so just close the range and return false.
311 				 */
312 				cp->startline = 0;
313 				r = 0;
314 			} else
315 				r = 1;
316 		} else if (cp->a1 && MATCH(cp->a1)) {
317 			/*
318 			 * If the second address is a number less than or
319 			 * equal to the line number first selected, only
320 			 * one line shall be selected.
321 			 *	-- POSIX 1003.2
322 			 * Likewise if the relative second line address is zero.
323 			 */
324 			if ((cp->a2->type == AT_LINE &&
325 			    linenum >= cp->a2->u.l) ||
326 			    (cp->a2->type == AT_RELLINE && cp->a2->u.l == 0))
327 				lastaddr = 1;
328 			else {
329 				cp->startline = linenum;
330 			}
331 			r = 1;
332 		} else
333 			r = 0;
334 	else
335 		r = MATCH(cp->a1);
336 	return (cp->nonsel ? ! r : r);
337 }
338 
339 /*
340  * Reset the sed processor to its initial state.
341  */
342 void
343 resetstate(void)
344 {
345 	struct s_command *cp;
346 
347 	/*
348 	 * Reset all in-range markers.
349 	 */
350 	for (cp = prog; cp; cp = cp->code == '{' ? cp->u.c : cp->next)
351 		if (cp->a2)
352 			cp->startline = 0;
353 
354 	/*
355 	 * Clear out the hold space.
356 	 */
357 	cspace(&HS, "", 0, REPLACE);
358 }
359 
360 /*
361  * substitute --
362  *	Do substitutions in the pattern space.  Currently, we build a
363  *	copy of the new pattern space in the substitute space structure
364  *	and then swap them.
365  */
366 static int
367 substitute(struct s_command *cp)
368 {
369 	SPACE tspace;
370 	regex_t *re;
371 	regoff_t re_off, slen;
372 	int lastempty, n;
373 	char *s;
374 
375 	s = ps;
376 	re = cp->u.s->re;
377 	if (re == NULL) {
378 		if (defpreg != NULL && cp->u.s->maxbref > defpreg->re_nsub) {
379 			linenum = cp->u.s->linenum;
380 			errx(1, "%lu: %s: \\%u not defined in the RE",
381 					linenum, fname, cp->u.s->maxbref);
382 		}
383 	}
384 	if (!regexec_e(re, s, 0, 0, psl))
385 		return (0);
386 
387 	SS.len = 0;				/* Clean substitute space. */
388 	slen = (regoff_t)psl;
389 	n = cp->u.s->n;
390 	lastempty = 1;
391 
392 	switch (n) {
393 	case 0:					/* Global */
394 		do {
395 			if (lastempty || match[0].rm_so != match[0].rm_eo) {
396 				/* Locate start of replaced string. */
397 				re_off = match[0].rm_so;
398 				/* Copy leading retained string. */
399 				cspace(&SS, s, (size_t)re_off, APPEND);
400 				/* Add in regular expression. */
401 				regsub(&SS, s, cp->u.s->new);
402 			}
403 
404 			/* Move past this match. */
405 			if (match[0].rm_so != match[0].rm_eo) {
406 				s += match[0].rm_eo;
407 				slen -= match[0].rm_eo;
408 				lastempty = 0;
409 			} else {
410 				if (match[0].rm_so < slen)
411 					cspace(&SS, s + match[0].rm_so, 1,
412 					    APPEND);
413 				s += match[0].rm_so + 1;
414 				slen -= match[0].rm_so + 1;
415 				lastempty = 1;
416 			}
417 		} while (slen >= 0 && regexec_e(re, s, REG_NOTBOL, 0, (size_t)slen));
418 		/* Copy trailing retained string. */
419 		if (slen > 0)
420 			cspace(&SS, s, (size_t)slen, APPEND);
421 		break;
422 	default:				/* Nth occurrence */
423 		while (--n) {
424 			if (match[0].rm_eo == match[0].rm_so)
425 				match[0].rm_eo = match[0].rm_so + 1;
426 			s += match[0].rm_eo;
427 			slen -= match[0].rm_eo;
428 			if (slen < 0)
429 				return (0);
430 			if (!regexec_e(re, s, REG_NOTBOL, 0, (size_t)slen))
431 				return (0);
432 		}
433 		/* FALLTHROUGH */
434 	case 1:					/* 1st occurrence */
435 		/* Locate start of replaced string. */
436 		re_off = match[0].rm_so + (s - ps);
437 		/* Copy leading retained string. */
438 		cspace(&SS, ps, (size_t)re_off, APPEND);
439 		/* Add in regular expression. */
440 		regsub(&SS, s, cp->u.s->new);
441 		/* Copy trailing retained string. */
442 		s += match[0].rm_eo;
443 		slen -= match[0].rm_eo;
444 		cspace(&SS, s, (size_t)slen, APPEND);
445 		break;
446 	}
447 
448 	/*
449 	 * Swap the substitute space and the pattern space, and make sure
450 	 * that any leftover pointers into stdio memory get lost.
451 	 */
452 	tspace = PS;
453 	PS = SS;
454 	SS = tspace;
455 	SS.space = SS.back;
456 
457 	/* Handle the 'p' flag. */
458 	if (cp->u.s->p)
459 		OUT();
460 
461 	/* Handle the 'w' flag. */
462 	if (cp->u.s->wfile && !pd) {
463 		if (cp->u.s->wfd == -1 && (cp->u.s->wfd = open(cp->u.s->wfile,
464 		    O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, DEFFILEMODE)) == -1)
465 			err(1, "%s", cp->u.s->wfile);
466 		if (write(cp->u.s->wfd, ps, psl) != (ssize_t)psl ||
467 		    write(cp->u.s->wfd, "\n", 1) != 1)
468 			err(1, "%s", cp->u.s->wfile);
469 	}
470 	return (1);
471 }
472 
473 /*
474  * do_tr --
475  *	Perform translation ('y' command) in the pattern space.
476  */
477 static void
478 do_tr(struct s_tr *y)
479 {
480 	SPACE tmp;
481 	char c, *p;
482 	size_t clen, left;
483 	size_t i;
484 
485 	if (MB_CUR_MAX == 1) {
486 		/*
487 		 * Single-byte encoding: perform in-place translation
488 		 * of the pattern space.
489 		 */
490 		for (p = ps; p < &ps[psl]; p++)
491 			*p = (char)y->bytetab[(u_char)*p];
492 	} else {
493 		/*
494 		 * Multi-byte encoding: perform translation into the
495 		 * translation space, then swap the translation and
496 		 * pattern spaces.
497 		 */
498 		/* Clean translation space. */
499 		YS.len = 0;
500 		for (p = ps, left = psl; left > 0; p += clen, left -= clen) {
501 			if ((c = (char)y->bytetab[(u_char)*p]) != '\0') {
502 				cspace(&YS, &c, 1, APPEND);
503 				clen = 1;
504 				continue;
505 			}
506 			for (i = 0; i < y->nmultis; i++)
507 				if (left >= y->multis[i].fromlen &&
508 				    memcmp(p, y->multis[i].from,
509 				    y->multis[i].fromlen) == 0)
510 					break;
511 			if (i < y->nmultis) {
512 				cspace(&YS, y->multis[i].to,
513 				    y->multis[i].tolen, APPEND);
514 				clen = y->multis[i].fromlen;
515 			} else {
516 				cspace(&YS, p, 1, APPEND);
517 				clen = 1;
518 			}
519 		}
520 		/* Swap the translation space and the pattern space. */
521 		tmp = PS;
522 		PS = YS;
523 		YS = tmp;
524 		YS.space = YS.back;
525 	}
526 }
527 
528 /*
529  * Flush append requests.  Always called before reading a line,
530  * therefore it also resets the substitution done (sdone) flag.
531  */
532 static void
533 flush_appends(void)
534 {
535 	FILE *f;
536 	size_t count, i;
537 	char buf[8 * 1024];
538 
539 	for (i = 0; i < appendx; i++)
540 		switch (appends[i].type) {
541 		case AP_STRING:
542 			fwrite(appends[i].s, sizeof(char), appends[i].len,
543 			    outfile);
544 			break;
545 		case AP_FILE:
546 			/*
547 			 * Read files probably shouldn't be cached.  Since
548 			 * it's not an error to read a non-existent file,
549 			 * it's possible that another program is interacting
550 			 * with the sed script through the filesystem.  It
551 			 * would be truly bizarre, but possible.  It's probably
552 			 * not that big a performance win, anyhow.
553 			 */
554 			if ((f = fopen(appends[i].s, "r")) == NULL)
555 				break;
556 			while ((count = fread(buf, sizeof(char), sizeof(buf), f)))
557 				(void)fwrite(buf, sizeof(char), count, outfile);
558 			(void)fclose(f);
559 			break;
560 		}
561 	if (ferror(outfile))
562 		errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
563 	appendx = 0;
564 	sdone = 0;
565 }
566 
567 static void
568 lputs(char *s, size_t len)
569 {
570 	static const char escapes[] = "\\\a\b\f\r\t\v";
571 	int c;
572 	size_t col, width;
573 	const char *p;
574 #ifdef TIOCGWINSZ
575 	struct winsize win;
576 #endif
577 	static size_t termwidth = (size_t)-1;
578 	size_t clen, i;
579 	wchar_t wc;
580 	mbstate_t mbs;
581 
582 	if (outfile != stdout)
583 		termwidth = 60;
584 	if (termwidth == (size_t)-1) {
585 		if ((p = getenv("COLUMNS")) && *p != '\0')
586 			termwidth = (size_t)atoi(p);
587 #ifdef TIOCGWINSZ
588 		else if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &win) == 0 &&
589 		    win.ws_col > 0)
590 			termwidth = win.ws_col;
591 #endif
592 		else
593 			termwidth = 60;
594 	}
595 	if (termwidth == 0)
596 		termwidth = 1;
597 
598 	memset(&mbs, 0, sizeof(mbs));
599 	col = 0;
600 	while (len != 0) {
601 		clen = mbrtowc(&wc, s, len, &mbs);
602 		if (clen == 0)
603 			clen = 1;
604 		if (clen == (size_t)-1 || clen == (size_t)-2) {
605 			wc = (unsigned char)*s;
606 			clen = 1;
607 			memset(&mbs, 0, sizeof(mbs));
608 		}
609 		if (wc == '\n') {
610 			if (col + 1 >= termwidth)
611 				fprintf(outfile, "\\\n");
612 			fputc('$', outfile);
613 			fputc('\n', outfile);
614 			col = 0;
615 		} else if (iswprint(wc)) {
616 			width = (size_t)wcwidth(wc);
617 			if (col + width >= termwidth) {
618 				fprintf(outfile, "\\\n");
619 				col = 0;
620 			}
621 			fwrite(s, 1, clen, outfile);
622 			col += width;
623 		} else if (wc != L'\0' && (c = wctob(wc)) != EOF &&
624 		    (p = strchr(escapes, c)) != NULL) {
625 			if (col + 2 >= termwidth) {
626 				fprintf(outfile, "\\\n");
627 				col = 0;
628 			}
629 			fprintf(outfile, "\\%c", "\\abfrtv"[p - escapes]);
630 			col += 2;
631 		} else {
632 			if (col + 4 * clen >= termwidth) {
633 				fprintf(outfile, "\\\n");
634 				col = 0;
635 			}
636 			for (i = 0; i < clen; i++)
637 				fprintf(outfile, "\\%03o",
638 				    (int)(unsigned char)s[i]);
639 			col += 4 * clen;
640 		}
641 		s += clen;
642 		len -= clen;
643 	}
644 	if (col + 1 >= termwidth)
645 		fprintf(outfile, "\\\n");
646 	(void)fputc('$', outfile);
647 	(void)fputc('\n', outfile);
648 	if (ferror(outfile))
649 		errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
650 }
651 
652 static __inline int
653 regexec_e(regex_t *preg, const char *string, int eflags, int nomatch,
654 	size_t slen)
655 {
656 	int eval;
657 #ifndef REG_STARTEND
658 	char *buf;
659 #endif
660 
661 	if (preg == NULL) {
662 		if (defpreg == NULL)
663 			errx(1, "first RE may not be empty");
664 	} else
665 		defpreg = preg;
666 
667 	/* Set anchors */
668 #ifndef REG_STARTEND
669 	buf = xmalloc(slen + 1);
670 	(void)memcpy(buf, string, slen);
671 	buf[slen] = '\0';
672 	eval = regexec(defpreg, buf,
673 	    nomatch ? 0 : maxnsub + 1, match, eflags);
674 	free(buf);
675 #else
676 	match[0].rm_so = 0;
677 	match[0].rm_eo = (regoff_t)slen;
678 	eval = regexec(defpreg, string,
679 	    nomatch ? 0 : maxnsub + 1, match, eflags | REG_STARTEND);
680 #endif
681 	switch(eval) {
682 	case 0:
683 		return (1);
684 	case REG_NOMATCH:
685 		return (0);
686 	}
687 	errx(1, "RE error: %s", strregerror(eval, defpreg));
688 	/* NOTREACHED */
689 }
690 
691 /*
692  * regsub - perform substitutions after a regexp match
693  * Based on a routine by Henry Spencer
694  */
695 static void
696 regsub(SPACE *sp, char *string, char *src)
697 {
698 	size_t len;
699 	int no;
700 	char c, *dst;
701 
702 #define	NEEDSP(reqlen)							\
703 	/* XXX What is the +1 for? */					\
704 	if (sp->len + (reqlen) + 1 >= sp->blen) {			\
705 		sp->blen += (reqlen) + 1024;				\
706 		sp->space = sp->back = xrealloc(sp->back, sp->blen);	\
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 = (size_t)(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 		sp->space = sp->back = xrealloc(sp->back, sp->blen);
751 	}
752 
753 	if (spflag == REPLACE)
754 		sp->len = 0;
755 
756 	memmove(sp->space + sp->len, p, len);
757 
758 	sp->space[sp->len += len] = '\0';
759 }
760 
761 /*
762  * Close all cached opened files and report any errors
763  */
764 void
765 cfclose(struct s_command *cp, struct s_command *end)
766 {
767 
768 	for (; cp != end; cp = cp->next)
769 		switch(cp->code) {
770 		case 's':
771 			if (cp->u.s->wfd != -1 && close(cp->u.s->wfd))
772 				err(1, "%s", cp->u.s->wfile);
773 			cp->u.s->wfd = -1;
774 			break;
775 		case 'w':
776 			if (cp->u.fd != -1 && close(cp->u.fd))
777 				err(1, "%s", cp->t);
778 			cp->u.fd = -1;
779 			break;
780 		case '{':
781 			cfclose(cp->u.c, cp->next);
782 			break;
783 		}
784 }
785