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
  34 #include <sys/cdefs.h>
  35 __FBSDID("$FreeBSD$");
  36
  37 #ifndef lint
  38 static const char sccsid[] = "@(#)process.c     8.6 (Berkeley) 4/20/94";
  39 #endif
  40
  41 #include <sys/types.h>
  42 #include <sys/stat.h>
  43 #include <sys/ioctl.h>
  44 #include <sys/uio.h>
  45
  46 #include <ctype.h>
  47 #include <err.h>
  48 #include <errno.h>
  49 #include <fcntl.h>
  50 #include <limits.h>
  51 #include <regex.h>
  52 #include <stdio.h>
  53 #include <stdlib.h>
  54 #include <string.h>
  55 #include <unistd.h>
  56 #include <wchar.h>
  57 #include <wctype.h>
  58
  59 #include "defs.h"
  60 #include "extern.h"
  61
  62 static SPACE HS, PS, SS, YS;
  63 #define pd              PS.deleted
  64 #define ps              PS.space
  65 #define psl             PS.len
  66 #define hs              HS.space
  67 #define hsl             HS.len
  68
  69 static inline int        applies(struct s_command *);
  70 static void              do_tr(struct s_tr *);
  71 static void              flush_appends(void);
  72 static void              lputs(char *, size_t);
  73 static int               regexec_e(regex_t *, const char *, int, int, size_t);
  74 static void              regsub(SPACE *, char *, char *);
  75 static int               substitute(struct s_command *);
  76
  77 struct s_appends *appends;      /* Array of pointers to strings to append. */
  78 static int appendx;             /* Index into appends array. */
  79 int appendnum;                  /* Size of appends array. */
  80
  81 static int lastaddr;            /* Set by applies if last address of a range. */
  82 static int sdone;               /* If any substitutes since last line input. */
  83                                 /* Iov structure for 'w' commands. */
  84 static regex_t *defpreg;
  85 size_t maxnsub;
  86 regmatch_t *match;
  87
  88 #define OUT() do {fwrite(ps, 1, psl, outfile); fputc('\n', outfile);} while (0)
  89
  90 void
  91 process(void)
  92 {
  93         struct s_command *cp;
  94         SPACE tspace;
  95         size_t oldpsl = 0;
  96         char *p;
  97
  98         p = NULL;
  99
 100         for (linenum = 0; mf_fgets(&PS, REPLACE);) {
 101                 pd = 0;
 102 top:
 103                 cp = prog;
 104 redirect:
 105                 while (cp != NULL) {
 106                         if (!applies(cp)) {
 107                                 cp = cp->next;
 108                                 continue;
 109                         }
 110                         switch (cp->code) {
 111                         case '{':
 112                                 cp = cp->u.c;
 113                                 goto redirect;
 114                         case 'a':
 115                                 if (appendx >= appendnum)
 116                                         if ((appends = realloc(appends,
 117                                             sizeof(struct s_appends) *
 118                                             (appendnum *= 2))) == NULL)
 119                                                 err(1, "realloc");
 120                                 appends[appendx].type = AP_STRING;
 121                                 appends[appendx].s = cp->t;
 122                                 appends[appendx].len = strlen(cp->t);
 123                                 appendx++;
 124                                 break;
 125                         case 'b':
 126                                 cp = cp->u.c;
 127                                 goto redirect;
 128                         case 'c':
 129                                 pd = 1;
 130                                 psl = 0;
 131                                 if (cp->a2 == NULL || lastaddr || lastline())
 132                                         (void)fprintf(outfile, "%s", cp->t);
 133                                 break;
 134                         case 'd':
 135                                 pd = 1;
 136                                 goto new;
 137                         case 'D':
 138                                 if (pd)
 139                                         goto new;
 140                                 if (psl == 0 ||
 141                                     (p = memchr(ps, '\n', psl)) == NULL) {
 142                                         pd = 1;
 143                                         goto new;
 144                                 } else {
 145                                         psl -= (p + 1) - ps;
 146                                         memmove(ps, p + 1, psl);
 147                                         goto top;
 148                                 }
 149                         case 'g':
 150                                 cspace(&PS, hs, hsl, REPLACE);
 151                                 break;
 152                         case 'G':
 153                                 cspace(&PS, "\n", 1, APPEND);
 154                                 cspace(&PS, hs, hsl, APPEND);
 155                                 break;
 156                         case 'h':
 157                                 cspace(&HS, ps, psl, REPLACE);
 158                                 break;
 159                         case 'H':
 160                                 cspace(&HS, "\n", 1, APPEND);
 161                                 cspace(&HS, ps, psl, APPEND);
 162                                 break;
 163                         case 'i':
 164                                 (void)fprintf(outfile, "%s", cp->t);
 165                                 break;
 166                         case 'l':
 167                                 lputs(ps, psl);
 168                                 break;
 169                         case 'n':
 170                                 if (!nflag && !pd)
 171                                         OUT();
 172                                 flush_appends();
 173                                 if (!mf_fgets(&PS, REPLACE))
 174                                         exit(0);
 175                                 pd = 0;
 176                                 break;
 177                         case 'N':
 178                                 flush_appends();
 179                                 cspace(&PS, "\n", 1, APPEND);
 180                                 if (!mf_fgets(&PS, APPEND))
 181                                         exit(0);
 182                                 break;
 183                         case 'p':
 184                                 if (pd)
 185                                         break;
 186                                 OUT();
 187                                 break;
 188                         case 'P':
 189                                 if (pd)
 190                                         break;
 191                                 if ((p = memchr(ps, '\n', psl)) != NULL) {
 192                                         oldpsl = psl;
 193                                         psl = p - ps;
 194                                 }
 195                                 OUT();
 196                                 if (p != NULL)
 197                                         psl = oldpsl;
 198                                 break;
 199                         case 'q':
 200                                 if (!nflag && !pd)
 201                                         OUT();
 202                                 flush_appends();
 203                                 exit(0);
 204                         case 'r':
 205                                 if (appendx >= appendnum)
 206                                         if ((appends = realloc(appends,
 207                                             sizeof(struct s_appends) *
 208                                             (appendnum *= 2))) == NULL)
 209                                                 err(1, "realloc");
 210                                 appends[appendx].type = AP_FILE;
 211                                 appends[appendx].s = cp->t;
 212                                 appends[appendx].len = strlen(cp->t);
 213                                 appendx++;
 214                                 break;
 215                         case 's':
 216                                 sdone |= substitute(cp);
 217                                 break;
 218                         case 't':
 219                                 if (sdone) {
 220                                         sdone = 0;
 221                                         cp = cp->u.c;
 222                                         goto redirect;
 223                                 }
 224                                 break;
 225                         case 'w':
 226                                 if (pd)
 227                                         break;
 228                                 if (cp->u.fd == -1 && (cp->u.fd = open(cp->t,
 229                                     O_WRONLY|O_APPEND|O_CREAT|O_TRUNC,
 230                                     DEFFILEMODE)) == -1)
 231                                         err(1, "%s", cp->t);
 232                                 if (write(cp->u.fd, ps, psl) != (ssize_t)psl ||
 233                                     write(cp->u.fd, "\n", 1) != 1)
 234                                         err(1, "%s", cp->t);
 235                                 break;
 236                         case 'x':
 237                                 /*
 238                                  * If the hold space is null, make it empty
 239                                  * but not null.  Otherwise the pattern space
 240                                  * will become null after the swap, which is
 241                                  * an abnormal condition.
 242                                  */
 243                                 if (hs == NULL)
 244                                         cspace(&HS, "", 0, REPLACE);
 245                                 tspace = PS;
 246                                 PS = HS;
 247                                 HS = tspace;
 248                                 break;
 249                         case 'y':
 250                                 if (pd || psl == 0)
 251                                         break;
 252                                 do_tr(cp->u.y);
 253                                 break;
 254                         case ':':
 255                         case '}':
 256                                 break;
 257                         case '=':
 258                                 (void)fprintf(outfile, "%lu\n", linenum);
 259                         }
 260                         cp = cp->next;
 261                 } /* for all cp */
 262
 263 new:            if (!nflag && !pd)
 264                         OUT();
 265                 flush_appends();
 266         } /* for all lines */
 267 }
 268
 269 /*
 270  * TRUE if the address passed matches the current program state
 271  * (lastline, linenumber, ps).
 272  */
 273 #define MATCH(a)                                                        \
 274         ((a)->type == AT_RE ? regexec_e((a)->u.r, ps, 0, 1, psl) :      \
 275             (a)->type == AT_LINE ? linenum == (a)->u.l : lastline())
 276
 277 /*
 278  * Return TRUE if the command applies to the current line.  Sets the start
 279  * line for process ranges.  Interprets the non-select (``!'') flag.
 280  */
 281 static inline int
 282 applies(struct s_command *cp)
 283 {
 284         int r;
 285
 286         lastaddr = 0;
 287         if (cp->a1 == NULL && cp->a2 == NULL)
 288                 r = 1;
 289         else if (cp->a2)
 290                 if (cp->startline > 0) {
 291                         switch (cp->a2->type) {
 292                         case AT_RELLINE:
 293                                 if (linenum - cp->startline <= cp->a2->u.l)
 294                                         r = 1;
 295                                 else {
 296                                         cp->startline = 0;
 297                                         r = 0;
 298                                 }
 299                                 break;
 300                         default:
 301                                 if (MATCH(cp->a2)) {
 302                                         cp->startline = 0;
 303                                         lastaddr = 1;
 304                                         r = 1;
 305                                 } else if (cp->a2->type == AT_LINE &&
 306                                             linenum > cp->a2->u.l) {
 307                                         /*
 308                                          * We missed the 2nd address due to a
 309                                          * branch, so just close the range and
 310                                          * return false.
 311                                          */
 312                                         cp->startline = 0;
 313                                         r = 0;
 314                                 } else
 315                                         r = 1;
 316                         }
 317                 } else if (cp->a1 && MATCH(cp->a1)) {
 318                         /*
 319                          * If the second address is a number less than or
 320                          * equal to the line number first selected, only
 321                          * one line shall be selected.
 322                          *      -- POSIX 1003.2
 323                          * Likewise if the relative second line address is zero.
 324                          */
 325                         if ((cp->a2->type == AT_LINE &&
 326                             linenum >= cp->a2->u.l) ||
 327                             (cp->a2->type == AT_RELLINE && cp->a2->u.l == 0))
 328                                 lastaddr = 1;
 329                         else {
 330                                 cp->startline = linenum;
 331                         }
 332                         r = 1;
 333                 } else
 334                         r = 0;
 335         else
 336                 r = MATCH(cp->a1);
 337         return (cp->nonsel ? ! r : r);
 338 }
 339
 340 /*
 341  * Reset the sed processor to its initial state.
 342  */
 343 void
 344 resetstate(void)
 345 {
 346         struct s_command *cp;
 347
 348         /*
 349          * Reset all in-range markers.
 350          */
 351         for (cp = prog; cp; cp = cp->code == '{' ? cp->u.c : cp->next)
 352                 if (cp->a2)
 353                         cp->startline = 0;
 354
 355         /*
 356          * Clear out the hold space.
 357          */
 358         cspace(&HS, "", 0, REPLACE);
 359 }
 360
 361 /*
 362  * substitute --
 363  *      Do substitutions in the pattern space.  Currently, we build a
 364  *      copy of the new pattern space in the substitute space structure
 365  *      and then swap them.
 366  */
 367 static int
 368 substitute(struct s_command *cp)
 369 {
 370         SPACE tspace;
 371         regex_t *re;
 372         regoff_t re_off, slen;
 373         int lastempty, n;
 374         char *s;
 375
 376         s = ps;
 377         re = cp->u.s->re;
 378         if (re == NULL) {
 379                 if (defpreg != NULL && cp->u.s->maxbref > defpreg->re_nsub) {
 380                         linenum = cp->u.s->linenum;
 381                         errx(1, "%lu: %s: \\%u not defined in the RE",
 382                                         linenum, fname, cp->u.s->maxbref);
 383                 }
 384         }
 385         if (!regexec_e(re, s, 0, 0, psl))
 386                 return (0);
 387
 388         SS.len = 0;                             /* Clean substitute space. */
 389         slen = psl;
 390         n = cp->u.s->n;
 391         lastempty = 1;
 392
 393         switch (n) {
 394         case 0:                                 /* Global */
 395                 do {
 396                         if (lastempty || match[0].rm_so != match[0].rm_eo) {
 397                                 /* Locate start of replaced string. */
 398                                 re_off = match[0].rm_so;
 399                                 /* Copy leading retained string. */
 400                                 cspace(&SS, s, re_off, APPEND);
 401                                 /* Add in regular expression. */
 402                                 regsub(&SS, s, cp->u.s->new);
 403                         }
 404
 405                         /* Move past this match. */
 406                         if (match[0].rm_so != match[0].rm_eo) {
 407                                 s += match[0].rm_eo;
 408                                 slen -= match[0].rm_eo;
 409                                 lastempty = 0;
 410                         } else {
 411                                 if (match[0].rm_so < slen)
 412                                         cspace(&SS, s + match[0].rm_so, 1,
 413                                             APPEND);
 414                                 s += match[0].rm_so + 1;
 415                                 slen -= match[0].rm_so + 1;
 416                                 lastempty = 1;
 417                         }
 418                 } while (slen >= 0 && regexec_e(re, s, REG_NOTBOL, 0, slen));
 419                 /* Copy trailing retained string. */
 420                 if (slen > 0)
 421                         cspace(&SS, s, slen, APPEND);
 422                 break;
 423         default:                                /* Nth occurrence */
 424                 while (--n) {
 425                         if (match[0].rm_eo == match[0].rm_so)
 426                                 match[0].rm_eo = match[0].rm_so + 1;
 427                         s += match[0].rm_eo;
 428                         slen -= match[0].rm_eo;
 429                         if (slen < 0)
 430                                 return (0);
 431                         if (!regexec_e(re, s, REG_NOTBOL, 0, slen))
 432                                 return (0);
 433                 }
 434                 /* FALLTHROUGH */
 435         case 1:                                 /* 1st occurrence */
 436                 /* Locate start of replaced string. */
 437                 re_off = match[0].rm_so + (s - ps);
 438                 /* Copy leading retained string. */
 439                 cspace(&SS, ps, re_off, APPEND);
 440                 /* Add in regular expression. */
 441                 regsub(&SS, s, cp->u.s->new);
 442                 /* Copy trailing retained string. */
 443                 s += match[0].rm_eo;
 444                 slen -= match[0].rm_eo;
 445                 cspace(&SS, s, slen, APPEND);
 446                 break;
 447         }
 448
 449         /*
 450          * Swap the substitute space and the pattern space, and make sure
 451          * that any leftover pointers into stdio memory get lost.
 452          */
 453         tspace = PS;
 454         PS = SS;
 455         SS = tspace;
 456         SS.space = SS.back;
 457
 458         /* Handle the 'p' flag. */
 459         if (cp->u.s->p)
 460                 OUT();
 461
 462         /* Handle the 'w' flag. */
 463         if (cp->u.s->wfile && !pd) {
 464                 if (cp->u.s->wfd == -1 && (cp->u.s->wfd = open(cp->u.s->wfile,
 465                     O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, DEFFILEMODE)) == -1)
 466                         err(1, "%s", cp->u.s->wfile);
 467                 if (write(cp->u.s->wfd, ps, psl) != (ssize_t)psl ||
 468                     write(cp->u.s->wfd, "\n", 1) != 1)
 469                         err(1, "%s", cp->u.s->wfile);
 470         }
 471         return (1);
 472 }
 473
 474 /*
 475  * do_tr --
 476  *      Perform translation ('y' command) in the pattern space.
 477  */
 478 static void
 479 do_tr(struct s_tr *y)
 480 {
 481         SPACE tmp;
 482         char c, *p;
 483         size_t clen, left;
 484         int i;
 485
 486         if (MB_CUR_MAX == 1) {
 487                 /*
 488                  * Single-byte encoding: perform in-place translation
 489                  * of the pattern space.
 490                  */
 491                 for (p = ps; p < &ps[psl]; p++)
 492                         *p = y->bytetab[(u_char)*p];
 493         } else {
 494                 /*
 495                  * Multi-byte encoding: perform translation into the
 496                  * translation space, then swap the translation and
 497                  * pattern spaces.
 498                  */
 499                 /* Clean translation space. */
 500                 YS.len = 0;
 501                 for (p = ps, left = psl; left > 0; p += clen, left -= clen) {
 502                         if ((c = y->bytetab[(u_char)*p]) != '\0') {
 503                                 cspace(&YS, &c, 1, APPEND);
 504                                 clen = 1;
 505                                 continue;
 506                         }
 507                         for (i = 0; i < y->nmultis; i++)
 508                                 if (left >= y->multis[i].fromlen &&
 509                                     memcmp(p, y->multis[i].from,
 510                                     y->multis[i].fromlen) == 0)
 511                                         break;
 512                         if (i < y->nmultis) {
 513                                 cspace(&YS, y->multis[i].to,
 514                                     y->multis[i].tolen, APPEND);
 515                                 clen = y->multis[i].fromlen;
 516                         } else {
 517                                 cspace(&YS, p, 1, APPEND);
 518                                 clen = 1;
 519                         }
 520                 }
 521                 /* Swap the translation space and the pattern space. */
 522                 tmp = PS;
 523                 PS = YS;
 524                 YS = tmp;
 525                 YS.space = YS.back;
 526         }
 527 }
 528
 529 /*
 530  * Flush append requests.  Always called before reading a line,
 531  * therefore it also resets the substitution done (sdone) flag.
 532  */
 533 static void
 534 flush_appends(void)
 535 {
 536         FILE *f;
 537         int count, i;
 538         char buf[8 * 1024];
 539
 540         for (i = 0; i < appendx; i++)
 541                 switch (appends[i].type) {
 542                 case AP_STRING:
 543                         fwrite(appends[i].s, sizeof(char), appends[i].len,
 544                             outfile);
 545                         break;
 546                 case AP_FILE:
 547                         /*
 548                          * Read files probably shouldn't be cached.  Since
 549                          * it's not an error to read a non-existent file,
 550                          * it's possible that another program is interacting
 551                          * with the sed script through the filesystem.  It
 552                          * would be truly bizarre, but possible.  It's probably
 553                          * not that big a performance win, anyhow.
 554                          */
 555                         if ((f = fopen(appends[i].s, "r")) == NULL)
 556                                 break;
 557                         while ((count = fread(buf, sizeof(char), sizeof(buf), f)))
 558                                 (void)fwrite(buf, sizeof(char), count, outfile);
 559                         (void)fclose(f);
 560                         break;
 561                 }
 562         if (ferror(outfile))
 563                 errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
 564         appendx = 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, col, width;
 572         const char *p;
 573         struct winsize win;
 574         static int termwidth = -1;
 575         size_t clen, i;
 576         wchar_t wc;
 577         mbstate_t mbs;
 578
 579         if (outfile != stdout)
 580                 termwidth = 60;
 581         if (termwidth == -1) {
 582                 if ((p = getenv("COLUMNS")) && *p != '\0')
 583                         termwidth = atoi(p);
 584                 else if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &win) == 0 &&
 585                     win.ws_col > 0)
 586                         termwidth = win.ws_col;
 587                 else
 588                         termwidth = 60;
 589         }
 590         if (termwidth <= 0)
 591                 termwidth = 1;
 592
 593         memset(&mbs, 0, sizeof(mbs));
 594         col = 0;
 595         while (len != 0) {
 596                 clen = mbrtowc(&wc, s, len, &mbs);
 597                 if (clen == 0)
 598                         clen = 1;
 599                 if (clen == (size_t)-1 || clen == (size_t)-2) {
 600                         wc = (unsigned char)*s;
 601                         clen = 1;
 602                         memset(&mbs, 0, sizeof(mbs));
 603                 }
 604                 if (wc == '\n') {
 605                         if (col + 1 >= termwidth)
 606                                 fprintf(outfile, "\\\n");
 607                         fputc('$', outfile);
 608                         fputc('\n', outfile);
 609                         col = 0;
 610                 } else if (iswprint(wc)) {
 611                         width = wcwidth(wc);
 612                         if (col + width >= termwidth) {
 613                                 fprintf(outfile, "\\\n");
 614                                 col = 0;
 615                         }
 616                         fwrite(s, 1, clen, outfile);
 617                         col += width;
 618                 } else if (wc != L'\0' && (c = wctob(wc)) != EOF &&
 619                     (p = strchr(escapes, c)) != NULL) {
 620                         if (col + 2 >= termwidth) {
 621                                 fprintf(outfile, "\\\n");
 622                                 col = 0;
 623                         }
 624                         fprintf(outfile, "\\%c", "\\abfrtv"[p - escapes]);
 625                         col += 2;
 626                 } else {
 627                         if (col + 4 * clen >= (unsigned)termwidth) {
 628                                 fprintf(outfile, "\\\n");
 629                                 col = 0;
 630                         }
 631                         for (i = 0; i < clen; i++)
 632                                 fprintf(outfile, "\\%03o",
 633                                     (int)(unsigned char)s[i]);
 634                         col += 4 * clen;
 635                 }
 636                 s += clen;
 637                 len -= clen;
 638         }
 639         if (col + 1 >= termwidth)
 640                 fprintf(outfile, "\\\n");
 641         (void)fputc('$', outfile);
 642         (void)fputc('\n', outfile);
 643         if (ferror(outfile))
 644                 errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
 645 }
 646
 647 static int
 648 regexec_e(regex_t *preg, const char *string, int eflags, int nomatch,
 649         size_t slen)
 650 {
 651         int eval;
 652
 653         if (preg == NULL) {
 654                 if (defpreg == NULL)
 655                         errx(1, "first RE may not be empty");
 656         } else
 657                 defpreg = preg;
 658
 659         /* Set anchors */
 660         match[0].rm_so = 0;
 661         match[0].rm_eo = slen;
 662
 663         eval = regexec(defpreg, string,
 664             nomatch ? 0 : maxnsub + 1, match, eflags | REG_STARTEND);
 665         switch(eval) {
 666         case 0:
 667                 return (1);
 668         case REG_NOMATCH:
 669                 return (0);
 670         }
 671         errx(1, "RE error: %s", strregerror(eval, defpreg));
 672         /* NOTREACHED */
 673 }
 674
 675 /*
 676  * regsub - perform substitutions after a regexp match
 677  * Based on a routine by Henry Spencer
 678  */
 679 static void
 680 regsub(SPACE *sp, char *string, char *src)
 681 {
 682         int len, no;
 683         char c, *dst;
 684
 685 #define NEEDSP(reqlen)                                                  \
 686         /* XXX What is the +1 for? */                                   \
 687         if (sp->len + (reqlen) + 1 >= sp->blen) {                       \
 688                 sp->blen += (reqlen) + 1024;                            \
 689                 if ((sp->space = sp->back = realloc(sp->back, sp->blen)) \
 690                     == NULL)                                            \
 691                         err(1, "realloc");                              \
 692                 dst = sp->space + sp->len;                              \
 693         }
 694
 695         dst = sp->space + sp->len;
 696         while ((c = *src++) != '\0') {
 697                 if (c == '&')
 698                         no = 0;
 699                 else if (c == '\\' && isdigit((unsigned char)*src))
 700                         no = *src++ - '0';
 701                 else
 702                         no = -1;
 703                 if (no < 0) {           /* Ordinary character. */
 704                         if (c == '\\' && (*src == '\\' || *src == '&'))
 705                                 c = *src++;
 706                         NEEDSP(1);
 707                         *dst++ = c;
 708                         ++sp->len;
 709                 } else if (match[no].rm_so != -1 && match[no].rm_eo != -1) {
 710                         len = match[no].rm_eo - match[no].rm_so;
 711                         NEEDSP(len);
 712                         memmove(dst, string + match[no].rm_so, len);
 713                         dst += len;
 714                         sp->len += len;
 715                 }
 716         }
 717         NEEDSP(1);
 718         *dst = '\0';
 719 }
 720
 721 /*
 722  * cspace --
 723  *      Concatenate space: append the source space to the destination space,
 724  *      allocating new space as necessary.
 725  */
 726 void
 727 cspace(SPACE *sp, const char *p, size_t len, enum e_spflag spflag)
 728 {
 729         size_t tlen;
 730
 731         /* Make sure SPACE has enough memory and ramp up quickly. */
 732         tlen = sp->len + len + 1;
 733         if (tlen > sp->blen) {
 734                 sp->blen = tlen + 1024;
 735                 if ((sp->space = sp->back = realloc(sp->back, sp->blen)) ==
 736                     NULL)
 737                         err(1, "realloc");
 738         }
 739
 740         if (spflag == REPLACE)
 741                 sp->len = 0;
 742
 743         memmove(sp->space + sp->len, p, len);
 744
 745         sp->space[sp->len += len] = '\0';
 746 }
 747
 748 /*
 749  * Close all cached opened files and report any errors
 750  */
 751 void
 752 cfclose(struct s_command *cp, struct s_command *end)
 753 {
 754
 755         for (; cp != end; cp = cp->next)
 756                 switch(cp->code) {
 757                 case 's':
 758                         if (cp->u.s->wfd != -1 && close(cp->u.s->wfd))
 759                                 err(1, "%s", cp->u.s->wfile);
 760                         cp->u.s->wfd = -1;
 761                         break;
 762                 case 'w':
 763                         if (cp->u.fd != -1 && close(cp->u.fd))
 764                                 err(1, "%s", cp->t);
 765                         cp->u.fd = -1;
 766                         break;
 767                 case '{':
 768                         cfclose(cp->u.c, cp->next);
 769                         break;
 770                 }
 771 }