usr.bin/sed/process.c

   1 /*-
   2  * Copyright (c) 1992 Diomidis Spinellis.
   3  * Copyright (c) 1992, 1993, 1994
   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  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  * @(#)process.c        8.6 (Berkeley) 4/20/94
  34  * $FreeBSD: src/usr.bin/sed/process.c,v 1.50 2009/05/25 06:45:33 brian Exp $
  35  * $DragonFly: src/usr.bin/sed/process.c,v 1.6 2008/04/08 13:23:38 swildner Exp $
  36  */
  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 hs              HS.space
  64 #define hsl             HS.len
  65
  66 static __inline int      applies(struct s_command *);
  67 static void              do_tr(struct s_tr *);
  68 static void              flush_appends(void);
  69 static void              lputs(char *, size_t);
  70 static __inline int      regexec_e(regex_t *, const char *, int, int, size_t);
  71 static void              regsub(SPACE *, char *, char *);
  72 static int               substitute(struct s_command *);
  73
  74 struct s_appends *appends;      /* Array of pointers to strings to append. */
  75 static int appendx;             /* Index into appends array. */
  76 int appendnum;                  /* Size of appends array. */
  77
  78 static int lastaddr;            /* Set by applies if last address of a range. */
  79 static int sdone;               /* If any substitutes since last line input. */
  80                                 /* Iov structure for 'w' commands. */
  81 static regex_t *defpreg;
  82 size_t maxnsub;
  83 regmatch_t *match;
  84
  85 #define OUT() do {fwrite(ps, 1, psl, outfile); fputc('\n', outfile);} while (0)
  86
  87 void
  88 process(void)
  89 {
  90         struct s_command *cp;
  91         SPACE tspace;
  92         size_t oldpsl = 0;
  93         char *p;
  94
  95         p = NULL;
  96
  97         for (linenum = 0; mf_fgets(&PS, REPLACE);) {
  98                 pd = 0;
  99 top:
 100                 cp = prog;
 101 redirect:
 102                 while (cp != NULL) {
 103                         if (!applies(cp)) {
 104                                 cp = cp->next;
 105                                 continue;
 106                         }
 107                         switch (cp->code) {
 108                         case '{':
 109                                 cp = cp->u.c;
 110                                 goto redirect;
 111                         case 'a':
 112                                 if (appendx >= appendnum)
 113                                         if ((appends = realloc(appends,
 114                                             sizeof(struct s_appends) *
 115                                             (appendnum *= 2))) == NULL)
 116                                                 err(1, "realloc");
 117                                 appends[appendx].type = AP_STRING;
 118                                 appends[appendx].s = cp->t;
 119                                 appends[appendx].len = strlen(cp->t);
 120                                 appendx++;
 121                                 break;
 122                         case 'b':
 123                                 cp = cp->u.c;
 124                                 goto redirect;
 125                         case 'c':
 126                                 pd = 1;
 127                                 psl = 0;
 128                                 if (cp->a2 == NULL || lastaddr || lastline())
 129                                         (void)fprintf(outfile, "%s", cp->t);
 130                                 break;
 131                         case 'd':
 132                                 pd = 1;
 133                                 goto new;
 134                         case 'D':
 135                                 if (pd)
 136                                         goto new;
 137                                 if (psl == 0 ||
 138                                     (p = memchr(ps, '\n', psl)) == NULL) {
 139                                         pd = 1;
 140                                         goto new;
 141                                 } else {
 142                                         psl -= (p + 1) - ps;
 143                                         memmove(ps, p + 1, psl);
 144                                         goto top;
 145                                 }
 146                         case 'g':
 147                                 cspace(&PS, hs, hsl, REPLACE);
 148                                 break;
 149                         case 'G':
 150                                 cspace(&PS, "\n", 1, APPEND);
 151                                 cspace(&PS, hs, hsl, APPEND);
 152                                 break;
 153                         case 'h':
 154                                 cspace(&HS, ps, psl, REPLACE);
 155                                 break;
 156                         case 'H':
 157                                 cspace(&HS, "\n", 1, APPEND);
 158                                 cspace(&HS, ps, psl, APPEND);
 159                                 break;
 160                         case 'i':
 161                                 (void)fprintf(outfile, "%s", cp->t);
 162                                 break;
 163                         case 'l':
 164                                 lputs(ps, psl);
 165                                 break;
 166                         case 'n':
 167                                 if (!nflag && !pd)
 168                                         OUT();
 169                                 flush_appends();
 170                                 if (!mf_fgets(&PS, REPLACE))
 171                                         exit(0);
 172                                 pd = 0;
 173                                 break;
 174                         case 'N':
 175                                 flush_appends();
 176                                 cspace(&PS, "\n", 1, APPEND);
 177                                 if (!mf_fgets(&PS, APPEND))
 178                                         exit(0);
 179                                 break;
 180                         case 'p':
 181                                 if (pd)
 182                                         break;
 183                                 OUT();
 184                                 break;
 185                         case 'P':
 186                                 if (pd)
 187                                         break;
 188                                 if ((p = memchr(ps, '\n', psl)) != NULL) {
 189                                         oldpsl = psl;
 190                                         psl = p - ps;
 191                                 }
 192                                 OUT();
 193                                 if (p != NULL)
 194                                         psl = oldpsl;
 195                                 break;
 196                         case 'q':
 197                                 if (!nflag && !pd)
 198                                         OUT();
 199                                 flush_appends();
 200                                 exit(0);
 201                         case 'r':
 202                                 if (appendx >= appendnum)
 203                                         if ((appends = realloc(appends,
 204                                             sizeof(struct s_appends) *
 205                                             (appendnum *= 2))) == NULL)
 206                                                 err(1, "realloc");
 207                                 appends[appendx].type = AP_FILE;
 208                                 appends[appendx].s = cp->t;
 209                                 appends[appendx].len = strlen(cp->t);
 210                                 appendx++;
 211                                 break;
 212                         case 's':
 213                                 sdone |= substitute(cp);
 214                                 break;
 215                         case 't':
 216                                 if (sdone) {
 217                                         sdone = 0;
 218                                         cp = cp->u.c;
 219                                         goto redirect;
 220                                 }
 221                                 break;
 222                         case 'w':
 223                                 if (pd)
 224                                         break;
 225                                 if (cp->u.fd == -1 && (cp->u.fd = open(cp->t,
 226                                     O_WRONLY|O_APPEND|O_CREAT|O_TRUNC,
 227                                     DEFFILEMODE)) == -1)
 228                                         err(1, "%s", cp->t);
 229                                 if (write(cp->u.fd, ps, psl) != (ssize_t)psl ||
 230                                     write(cp->u.fd, "\n", 1) != 1)
 231                                         err(1, "%s", cp->t);
 232                                 break;
 233                         case 'x':
 234                                 /*
 235                                  * If the hold space is null, make it empty
 236                                  * but not null.  Otherwise the pattern space
 237                                  * will become null after the swap, which is
 238                                  * an abnormal condition.
 239                                  */
 240                                 if (hs == NULL)
 241                                         cspace(&HS, "", 0, REPLACE);
 242                                 tspace = PS;
 243                                 PS = HS;
 244                                 HS = tspace;
 245                                 break;
 246                         case 'y':
 247                                 if (pd || psl == 0)
 248                                         break;
 249                                 do_tr(cp->u.y);
 250                                 break;
 251                         case ':':
 252                         case '}':
 253                                 break;
 254                         case '=':
 255                                 (void)fprintf(outfile, "%lu\n", linenum);
 256                         }
 257                         cp = cp->next;
 258                 } /* for all cp */
 259
 260 new:            if (!nflag && !pd)
 261                         OUT();
 262                 flush_appends();
 263         } /* for all lines */
 264 }
 265
 266 /*
 267  * TRUE if the address passed matches the current program state
 268  * (lastline, linenumber, ps).
 269  */
 270 #define MATCH(a)                                                        \
 271         ((a)->type == AT_RE ? regexec_e((a)->u.r, ps, 0, 1, psl) :      \
 272             (a)->type == AT_LINE ? linenum == (a)->u.l : lastline())
 273
 274 /*
 275  * Return TRUE if the command applies to the current line.  Sets the start
 276  * line for process ranges.  Interprets the non-select (``!'') flag.
 277  */
 278 static __inline int
 279 applies(struct s_command *cp)
 280 {
 281         int r;
 282
 283         lastaddr = 0;
 284         if (cp->a1 == NULL && cp->a2 == NULL)
 285                 r = 1;
 286         else if (cp->a2)
 287                 if (cp->startline > 0) {
 288                         if (MATCH(cp->a2)) {
 289                                 cp->startline = 0;
 290                                 lastaddr = 1;
 291                                 r = 1;
 292                         } else if (linenum - cp->startline <= cp->a2->u.l)
 293                                 r = 1;
 294                         else if ((cp->a2->type == AT_LINE &&
 295                                    linenum > cp->a2->u.l) ||
 296                                    (cp->a2->type == AT_RELLINE &&
 297                                    linenum - cp->startline > cp->a2->u.l)) {
 298                                 /*
 299                                  * We missed the 2nd address due to a branch,
 300                                  * so just close the range and return false.
 301                                  */
 302                                 cp->startline = 0;
 303                                 r = 0;
 304                         } else
 305                                 r = 1;
 306                 } else if (MATCH(cp->a1)) {
 307                         /*
 308                          * If the second address is a number less than or
 309                          * equal to the line number first selected, only
 310                          * one line shall be selected.
 311                          *      -- POSIX 1003.2
 312                          * Likewise if the relative second line address is zero.
 313                          */
 314                         if ((cp->a2->type == AT_LINE &&
 315                             linenum >= cp->a2->u.l) ||
 316                             (cp->a2->type == AT_RELLINE && cp->a2->u.l == 0))
 317                                 lastaddr = 1;
 318                         else {
 319                                 cp->startline = linenum;
 320                         }
 321                         r = 1;
 322                 } else
 323                         r = 0;
 324         else
 325                 r = MATCH(cp->a1);
 326         return (cp->nonsel ? ! r : r);
 327 }
 328
 329 /*
 330  * Reset the sed processor to its initial state.
 331  */
 332 void
 333 resetstate(void)
 334 {
 335         struct s_command *cp;
 336
 337         /*
 338          * Reset all in-range markers.
 339          */
 340         for (cp = prog; cp; cp = cp->code == '{' ? cp->u.c : cp->next)
 341                 if (cp->a2)
 342                         cp->startline = 0;
 343
 344         /*
 345          * Clear out the hold space.
 346          */
 347         cspace(&HS, "", 0, REPLACE);
 348 }
 349
 350 /*
 351  * substitute --
 352  *      Do substitutions in the pattern space.  Currently, we build a
 353  *      copy of the new pattern space in the substitute space structure
 354  *      and then swap them.
 355  */
 356 static int
 357 substitute(struct s_command *cp)
 358 {
 359         SPACE tspace;
 360         regex_t *re;
 361         regoff_t re_off, slen;
 362         int lastempty, n;
 363         char *s;
 364
 365         s = ps;
 366         re = cp->u.s->re;
 367         if (re == NULL) {
 368                 if (defpreg != NULL && cp->u.s->maxbref > defpreg->re_nsub) {
 369                         linenum = cp->u.s->linenum;
 370                         errx(1, "%lu: %s: \\%u not defined in the RE",
 371                                         linenum, fname, cp->u.s->maxbref);
 372                 }
 373         }
 374         if (!regexec_e(re, s, 0, 0, psl))
 375                 return (0);
 376
 377         SS.len = 0;                             /* Clean substitute space. */
 378         slen = psl;
 379         n = cp->u.s->n;
 380         lastempty = 1;
 381
 382         switch (n) {
 383         case 0:                                 /* Global */
 384                 do {
 385                         if (lastempty || match[0].rm_so != match[0].rm_eo) {
 386                                 /* Locate start of replaced string. */
 387                                 re_off = match[0].rm_so;
 388                                 /* Copy leading retained string. */
 389                                 cspace(&SS, s, re_off, APPEND);
 390                                 /* Add in regular expression. */
 391                                 regsub(&SS, s, cp->u.s->new);
 392                         }
 393
 394                         /* Move past this match. */
 395                         if (match[0].rm_so != match[0].rm_eo) {
 396                                 s += match[0].rm_eo;
 397                                 slen -= match[0].rm_eo;
 398                                 lastempty = 0;
 399                         } else {
 400                                 if (match[0].rm_so < slen)
 401                                         cspace(&SS, s + match[0].rm_so, 1,
 402                                             APPEND);
 403                                 s += match[0].rm_so + 1;
 404                                 slen -= match[0].rm_so + 1;
 405                                 lastempty = 1;
 406                         }
 407                 } while (slen >= 0 && regexec_e(re, s, REG_NOTBOL, 0, slen));
 408                 /* Copy trailing retained string. */
 409                 if (slen > 0)
 410                         cspace(&SS, s, slen, APPEND);
 411                 break;
 412         default:                                /* Nth occurrence */
 413                 while (--n) {
 414                         if (match[0].rm_eo == match[0].rm_so)
 415                                 match[0].rm_eo = match[0].rm_so + 1;
 416                         s += match[0].rm_eo;
 417                         slen -= match[0].rm_eo;
 418                         if (slen < 0)
 419                                 return (0);
 420                         if (!regexec_e(re, s, REG_NOTBOL, 0, slen))
 421                                 return (0);
 422                 }
 423                 /* FALLTHROUGH */
 424         case 1:                                 /* 1st occurrence */
 425                 /* Locate start of replaced string. */
 426                 re_off = match[0].rm_so + (s - ps);
 427                 /* Copy leading retained string. */
 428                 cspace(&SS, ps, re_off, APPEND);
 429                 /* Add in regular expression. */
 430                 regsub(&SS, s, cp->u.s->new);
 431                 /* Copy trailing retained string. */
 432                 s += match[0].rm_eo;
 433                 slen -= match[0].rm_eo;
 434                 cspace(&SS, s, slen, APPEND);
 435                 break;
 436         }
 437
 438         /*
 439          * Swap the substitute space and the pattern space, and make sure
 440          * that any leftover pointers into stdio memory get lost.
 441          */
 442         tspace = PS;
 443         PS = SS;
 444         SS = tspace;
 445         SS.space = SS.back;
 446
 447         /* Handle the 'p' flag. */
 448         if (cp->u.s->p)
 449                 OUT();
 450
 451         /* Handle the 'w' flag. */
 452         if (cp->u.s->wfile && !pd) {
 453                 if (cp->u.s->wfd == -1 && (cp->u.s->wfd = open(cp->u.s->wfile,
 454                     O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, DEFFILEMODE)) == -1)
 455                         err(1, "%s", cp->u.s->wfile);
 456                 if (write(cp->u.s->wfd, ps, psl) != (ssize_t)psl ||
 457                     write(cp->u.s->wfd, "\n", 1) != 1)
 458                         err(1, "%s", cp->u.s->wfile);
 459         }
 460         return (1);
 461 }
 462
 463 /*
 464  * do_tr --
 465  *      Perform translation ('y' command) in the pattern space.
 466  */
 467 static void
 468 do_tr(struct s_tr *y)
 469 {
 470         SPACE tmp;
 471         char c, *p;
 472         size_t clen, left;
 473         int i;
 474
 475         if (MB_CUR_MAX == 1) {
 476                 /*
 477                  * Single-byte encoding: perform in-place translation
 478                  * of the pattern space.
 479                  */
 480                 for (p = ps; p < &ps[psl]; p++)
 481                         *p = y->bytetab[(u_char)*p];
 482         } else {
 483                 /*
 484                  * Multi-byte encoding: perform translation into the
 485                  * translation space, then swap the translation and
 486                  * pattern spaces.
 487                  */
 488                 /* Clean translation space. */
 489                 YS.len = 0;
 490                 for (p = ps, left = psl; left > 0; p += clen, left -= clen) {
 491                         if ((c = y->bytetab[(u_char)*p]) != '\0') {
 492                                 cspace(&YS, &c, 1, APPEND);
 493                                 clen = 1;
 494                                 continue;
 495                         }
 496                         for (i = 0; i < y->nmultis; i++)
 497                                 if (left >= y->multis[i].fromlen &&
 498                                     memcmp(p, y->multis[i].from,
 499                                     y->multis[i].fromlen) == 0)
 500                                         break;
 501                         if (i < y->nmultis) {
 502                                 cspace(&YS, y->multis[i].to,
 503                                     y->multis[i].tolen, APPEND);
 504                                 clen = y->multis[i].fromlen;
 505                         } else {
 506                                 cspace(&YS, p, 1, APPEND);
 507                                 clen = 1;
 508                         }
 509                 }
 510                 /* Swap the translation space and the pattern space. */
 511                 tmp = PS;
 512                 PS = YS;
 513                 YS = tmp;
 514                 YS.space = YS.back;
 515         }
 516 }
 517
 518 /*
 519  * Flush append requests.  Always called before reading a line,
 520  * therefore it also resets the substitution done (sdone) flag.
 521  */
 522 static void
 523 flush_appends(void)
 524 {
 525         FILE *f;
 526         int count, i;
 527         char buf[8 * 1024];
 528
 529         for (i = 0; i < appendx; i++)
 530                 switch (appends[i].type) {
 531                 case AP_STRING:
 532                         fwrite(appends[i].s, sizeof(char), appends[i].len,
 533                             outfile);
 534                         break;
 535                 case AP_FILE:
 536                         /*
 537                          * Read files probably shouldn't be cached.  Since
 538                          * it's not an error to read a non-existent file,
 539                          * it's possible that another program is interacting
 540                          * with the sed script through the filesystem.  It
 541                          * would be truly bizarre, but possible.  It's probably
 542                          * not that big a performance win, anyhow.
 543                          */
 544                         if ((f = fopen(appends[i].s, "r")) == NULL)
 545                                 break;
 546                         while ((count = fread(buf, sizeof(char), sizeof(buf), f)))
 547                                 (void)fwrite(buf, sizeof(char), count, outfile);
 548                         (void)fclose(f);
 549                         break;
 550                 }
 551         if (ferror(outfile))
 552                 errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
 553         appendx = sdone = 0;
 554 }
 555
 556 static void
 557 lputs(char *s, size_t len)
 558 {
 559         static const char escapes[] = "\\\a\b\f\r\t\v";
 560         int c, col, width;
 561         const char *p;
 562         struct winsize win;
 563         static int termwidth = -1;
 564         size_t clen, i;
 565         wchar_t wc;
 566         mbstate_t mbs;
 567
 568         if (outfile != stdout)
 569                 termwidth = 60;
 570         if (termwidth == -1) {
 571                 if ((p = getenv("COLUMNS")) && *p != '\0')
 572                         termwidth = atoi(p);
 573                 else if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &win) == 0 &&
 574                     win.ws_col > 0)
 575                         termwidth = win.ws_col;
 576                 else
 577                         termwidth = 60;
 578         }
 579         if (termwidth <= 0)
 580                 termwidth = 1;
 581
 582         memset(&mbs, 0, sizeof(mbs));
 583         col = 0;
 584         while (len != 0) {
 585                 clen = mbrtowc(&wc, s, len, &mbs);
 586                 if (clen == 0)
 587                         clen = 1;
 588                 if (clen == (size_t)-1 || clen == (size_t)-2) {
 589                         wc = (unsigned char)*s;
 590                         clen = 1;
 591                         memset(&mbs, 0, sizeof(mbs));
 592                 }
 593                 if (wc == '\n') {
 594                         if (col + 1 >= termwidth)
 595                                 fprintf(outfile, "\\\n");
 596                         fputc('$', outfile);
 597                         fputc('\n', outfile);
 598                         col = 0;
 599                 } else if (iswprint(wc)) {
 600                         width = wcwidth(wc);
 601                         if (col + width >= termwidth) {
 602                                 fprintf(outfile, "\\\n");
 603                                 col = 0;
 604                         }
 605                         fwrite(s, 1, clen, outfile);
 606                         col += width;
 607                 } else if (wc != L'\0' && (c = wctob(wc)) != EOF &&
 608                     (p = strchr(escapes, c)) != NULL) {
 609                         if (col + 2 >= termwidth) {
 610                                 fprintf(outfile, "\\\n");
 611                                 col = 0;
 612                         }
 613                         fprintf(outfile, "\\%c", "\\abfrtv"[p - escapes]);
 614                         col += 2;
 615                 } else {
 616                         if (col + 4 * clen >= (unsigned)termwidth) {
 617                                 fprintf(outfile, "\\\n");
 618                                 col = 0;
 619                         }
 620                         for (i = 0; i < clen; i++)
 621                                 fprintf(outfile, "\\%03o",
 622                                     (int)(unsigned char)s[i]);
 623                         col += 4 * clen;
 624                 }
 625                 s += clen;
 626                 len -= clen;
 627         }
 628         if (col + 1 >= termwidth)
 629                 fprintf(outfile, "\\\n");
 630         (void)fputc('$', outfile);
 631         (void)fputc('\n', outfile);
 632         if (ferror(outfile))
 633                 errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
 634 }
 635
 636 static __inline int
 637 regexec_e(regex_t *preg, const char *string, int eflags, int nomatch,
 638         size_t slen)
 639 {
 640         int eval;
 641
 642         if (preg == NULL) {
 643                 if (defpreg == NULL)
 644                         errx(1, "first RE may not be empty");
 645         } else
 646                 defpreg = preg;
 647
 648         /* Set anchors */
 649         match[0].rm_so = 0;
 650         match[0].rm_eo = slen;
 651
 652         eval = regexec(defpreg, string,
 653             nomatch ? 0 : maxnsub + 1, match, eflags | REG_STARTEND);
 654         switch(eval) {
 655         case 0:
 656                 return (1);
 657         case REG_NOMATCH:
 658                 return (0);
 659         }
 660         errx(1, "RE error: %s", strregerror(eval, defpreg));
 661         /* NOTREACHED */
 662 }
 663
 664 /*
 665  * regsub - perform substitutions after a regexp match
 666  * Based on a routine by Henry Spencer
 667  */
 668 static void
 669 regsub(SPACE *sp, char *string, char *src)
 670 {
 671         int len, no;
 672         char c, *dst;
 673
 674 #define NEEDSP(reqlen)                                                  \
 675         /* XXX What is the +1 for? */                                   \
 676         if (sp->len + (reqlen) + 1 >= sp->blen) {                       \
 677                 sp->blen += (reqlen) + 1024;                            \
 678                 if ((sp->space = sp->back = realloc(sp->back, sp->blen)) \
 679                     == NULL)                                            \
 680                         err(1, "realloc");                              \
 681                 dst = sp->space + sp->len;                              \
 682         }
 683
 684         dst = sp->space + sp->len;
 685         while ((c = *src++) != '\0') {
 686                 if (c == '&')
 687                         no = 0;
 688                 else if (c == '\\' && isdigit((unsigned char)*src))
 689                         no = *src++ - '0';
 690                 else
 691                         no = -1;
 692                 if (no < 0) {           /* Ordinary character. */
 693                         if (c == '\\' && (*src == '\\' || *src == '&'))
 694                                 c = *src++;
 695                         NEEDSP(1);
 696                         *dst++ = c;
 697                         ++sp->len;
 698                 } else if (match[no].rm_so != -1 && match[no].rm_eo != -1) {
 699                         len = match[no].rm_eo - match[no].rm_so;
 700                         NEEDSP(len);
 701                         memmove(dst, string + match[no].rm_so, len);
 702                         dst += len;
 703                         sp->len += len;
 704                 }
 705         }
 706         NEEDSP(1);
 707         *dst = '\0';
 708 }
 709
 710 /*
 711  * cspace --
 712  *      Concatenate space: append the source space to the destination space,
 713  *      allocating new space as necessary.
 714  */
 715 void
 716 cspace(SPACE *sp, const char *p, size_t len, enum e_spflag spflag)
 717 {
 718         size_t tlen;
 719
 720         /* Make sure SPACE has enough memory and ramp up quickly. */
 721         tlen = sp->len + len + 1;
 722         if (tlen > sp->blen) {
 723                 sp->blen = tlen + 1024;
 724                 if ((sp->space = sp->back = realloc(sp->back, sp->blen)) ==
 725                     NULL)
 726                         err(1, "realloc");
 727         }
 728
 729         if (spflag == REPLACE)
 730                 sp->len = 0;
 731
 732         memmove(sp->space + sp->len, p, len);
 733
 734         sp->space[sp->len += len] = '\0';
 735 }
 736
 737 /*
 738  * Close all cached opened files and report any errors
 739  */
 740 void
 741 cfclose(struct s_command *cp, struct s_command *end)
 742 {
 743
 744         for (; cp != end; cp = cp->next)
 745                 switch(cp->code) {
 746                 case 's':
 747                         if (cp->u.s->wfd != -1 && close(cp->u.s->wfd))
 748                                 err(1, "%s", cp->u.s->wfile);
 749                         cp->u.s->wfd = -1;
 750                         break;
 751                 case 'w':
 752                         if (cp->u.fd != -1 && close(cp->u.fd))
 753                                 err(1, "%s", cp->t);
 754                         cp->u.fd = -1;
 755                         break;
 756                 case '{':
 757                         cfclose(cp->u.c, cp->next);
 758                         break;
 759                 }
 760 }