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