usr.bin/sed/process.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-3-Clause
   3  *
   4  * Copyright (c) 1992 Diomidis Spinellis.
   5  * Copyright (c) 1992, 1993, 1994
   6  *      The Regents of the University of California.  All rights reserved.
   7  *
   8  * This code is derived from software contributed to Berkeley by
   9  * Diomidis Spinellis of Imperial College, University of London.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  * 3. Neither the name of the University nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #include <sys/cdefs.h>
  37 __FBSDID("$FreeBSD$");
  38
  39 #ifndef lint
  40 static const char sccsid[] = "@(#)process.c     8.6 (Berkeley) 4/20/94";
  41 #endif
  42
  43 #include <sys/types.h>
  44 #include <sys/stat.h>
  45 #include <sys/ioctl.h>
  46 #include <sys/uio.h>
  47
  48 #include <ctype.h>
  49 #include <err.h>
  50 #include <errno.h>
  51 #include <fcntl.h>
  52 #include <limits.h>
  53 #include <regex.h>
  54 #include <stdio.h>
  55 #include <stdlib.h>
  56 #include <string.h>
  57 #include <unistd.h>
  58 #include <wchar.h>
  59 #include <wctype.h>
  60
  61 #include "defs.h"
  62 #include "extern.h"
  63
  64 static SPACE HS, PS, SS, YS;
  65 #define pd              PS.deleted
  66 #define ps              PS.space
  67 #define psl             PS.len
  68 #define psanl           PS.append_newline
  69 #define hs              HS.space
  70 #define hsl             HS.len
  71
  72 static inline int        applies(struct s_command *);
  73 static void              do_tr(struct s_tr *);
  74 static void              flush_appends(void);
  75 static void              lputs(char *, size_t);
  76 static int               regexec_e(regex_t *, const char *, int, int, size_t,
  77                              size_t);
  78 static void              regsub(SPACE *, char *, char *);
  79 static int               substitute(struct s_command *);
  80
  81 struct s_appends *appends;      /* Array of pointers to strings to append. */
  82 static int appendx;             /* Index into appends array. */
  83 int appendnum;                  /* Size of appends array. */
  84
  85 static int lastaddr;            /* Set by applies if last address of a range. */
  86 static int sdone;               /* If any substitutes since last line input. */
  87                                 /* Iov structure for 'w' commands. */
  88 static regex_t *defpreg;
  89 size_t maxnsub;
  90 regmatch_t *match;
  91
  92 #define OUT() do {                                                      \
  93         fwrite(ps, 1, psl, outfile);                                    \
  94         if (psanl) fputc('\n', outfile);                                \
  95 } while (0)
  96
  97 void
  98 process(void)
  99 {
 100         struct s_command *cp;
 101         SPACE tspace;
 102         size_t oldpsl;
 103         char *p;
 104         int oldpsanl;
 105
 106         p = NULL;
 107         oldpsanl = oldpsl = 0;
 108
 109         for (linenum = 0; mf_fgets(&PS, REPLACE);) {
 110                 pd = 0;
 111 top:
 112                 cp = prog;
 113 redirect:
 114                 while (cp != NULL) {
 115                         if (!applies(cp)) {
 116                                 cp = cp->next;
 117                                 continue;
 118                         }
 119                         switch (cp->code) {
 120                         case '{':
 121                                 cp = cp->u.c;
 122                                 goto redirect;
 123                         case 'a':
 124                                 if (appendx >= appendnum)
 125                                         if ((appends = realloc(appends,
 126                                             sizeof(struct s_appends) *
 127                                             (appendnum *= 2))) == NULL)
 128                                                 err(1, "realloc");
 129                                 appends[appendx].type = AP_STRING;
 130                                 appends[appendx].s = cp->t;
 131                                 appends[appendx].len = strlen(cp->t);
 132                                 appendx++;
 133                                 break;
 134                         case 'b':
 135                                 cp = cp->u.c;
 136                                 goto redirect;
 137                         case 'c':
 138                                 pd = 1;
 139                                 psl = 0;
 140                                 if (cp->a2 == NULL || lastaddr || lastline())
 141                                         (void)fprintf(outfile, "%s", cp->t);
 142                                 break;
 143                         case 'd':
 144                                 pd = 1;
 145                                 goto new;
 146                         case 'D':
 147                                 if (pd)
 148                                         goto new;
 149                                 if (psl == 0 ||
 150                                     (p = memchr(ps, '\n', psl)) == NULL) {
 151                                         pd = 1;
 152                                         goto new;
 153                                 } else {
 154                                         psl -= (p + 1) - ps;
 155                                         memmove(ps, p + 1, psl);
 156                                         goto top;
 157                                 }
 158                         case 'g':
 159                                 cspace(&PS, hs, hsl, REPLACE);
 160                                 break;
 161                         case 'G':
 162                                 cspace(&PS, "\n", 1, APPEND);
 163                                 cspace(&PS, hs, hsl, APPEND);
 164                                 break;
 165                         case 'h':
 166                                 cspace(&HS, ps, psl, REPLACE);
 167                                 break;
 168                         case 'H':
 169                                 cspace(&HS, "\n", 1, APPEND);
 170                                 cspace(&HS, ps, psl, APPEND);
 171                                 break;
 172                         case 'i':
 173                                 (void)fprintf(outfile, "%s", cp->t);
 174                                 break;
 175                         case 'l':
 176                                 lputs(ps, psl);
 177                                 break;
 178                         case 'n':
 179                                 if (!nflag && !pd)
 180                                         OUT();
 181                                 flush_appends();
 182                                 if (!mf_fgets(&PS, REPLACE))
 183                                         exit(0);
 184                                 pd = 0;
 185                                 break;
 186                         case 'N':
 187                                 flush_appends();
 188                                 cspace(&PS, "\n", 1, APPEND);
 189                                 if (!mf_fgets(&PS, APPEND))
 190                                         exit(0);
 191                                 break;
 192                         case 'p':
 193                                 if (pd)
 194                                         break;
 195                                 OUT();
 196                                 break;
 197                         case 'P':
 198                                 if (pd)
 199                                         break;
 200                                 if ((p = memchr(ps, '\n', psl)) != NULL) {
 201                                         oldpsl = psl;
 202                                         oldpsanl = psanl;
 203                                         psl = p - ps;
 204                                         psanl = 1;
 205                                 }
 206                                 OUT();
 207                                 if (p != NULL) {
 208                                         psl = oldpsl;
 209                                         psanl = oldpsanl;
 210                                 }
 211                                 break;
 212                         case 'q':
 213                                 if (!nflag && !pd)
 214                                         OUT();
 215                                 flush_appends();
 216                                 exit(0);
 217                         case 'r':
 218                                 if (appendx >= appendnum)
 219                                         if ((appends = realloc(appends,
 220                                             sizeof(struct s_appends) *
 221                                             (appendnum *= 2))) == NULL)
 222                                                 err(1, "realloc");
 223                                 appends[appendx].type = AP_FILE;
 224                                 appends[appendx].s = cp->t;
 225                                 appends[appendx].len = strlen(cp->t);
 226                                 appendx++;
 227                                 break;
 228                         case 's':
 229                                 sdone |= substitute(cp);
 230                                 break;
 231                         case 't':
 232                                 if (sdone) {
 233                                         sdone = 0;
 234                                         cp = cp->u.c;
 235                                         goto redirect;
 236                                 }
 237                                 break;
 238                         case 'w':
 239                                 if (pd)
 240                                         break;
 241                                 if (cp->u.fd == -1 && (cp->u.fd = open(cp->t,
 242                                     O_WRONLY|O_APPEND|O_CREAT|O_TRUNC,
 243                                     DEFFILEMODE)) == -1)
 244                                         err(1, "%s", cp->t);
 245                                 if (write(cp->u.fd, ps, psl) != (ssize_t)psl ||
 246                                     write(cp->u.fd, "\n", 1) != 1)
 247                                         err(1, "%s", cp->t);
 248                                 break;
 249                         case 'x':
 250                                 /*
 251                                  * If the hold space is null, make it empty
 252                                  * but not null.  Otherwise the pattern space
 253                                  * will become null after the swap, which is
 254                                  * an abnormal condition.
 255                                  */
 256                                 if (hs == NULL)
 257                                         cspace(&HS, "", 0, REPLACE);
 258                                 tspace = PS;
 259                                 PS = HS;
 260                                 psanl = tspace.append_newline;
 261                                 HS = tspace;
 262                                 break;
 263                         case 'y':
 264                                 if (pd || psl == 0)
 265                                         break;
 266                                 do_tr(cp->u.y);
 267                                 break;
 268                         case ':':
 269                         case '}':
 270                                 break;
 271                         case '=':
 272                                 (void)fprintf(outfile, "%lu\n", linenum);
 273                         }
 274                         cp = cp->next;
 275                 } /* for all cp */
 276
 277 new:            if (!nflag && !pd)
 278                         OUT();
 279                 flush_appends();
 280         } /* for all lines */
 281 }
 282
 283 /*
 284  * TRUE if the address passed matches the current program state
 285  * (lastline, linenumber, ps).
 286  */
 287 #define MATCH(a)                                                        \
 288         ((a)->type == AT_RE ? regexec_e((a)->u.r, ps, 0, 1, 0, psl) :   \
 289             (a)->type == AT_LINE ? linenum == (a)->u.l : lastline())
 290
 291 /*
 292  * Return TRUE if the command applies to the current line.  Sets the start
 293  * line for process ranges.  Interprets the non-select (``!'') flag.
 294  */
 295 static inline int
 296 applies(struct s_command *cp)
 297 {
 298         int r;
 299
 300         lastaddr = 0;
 301         if (cp->a1 == NULL && cp->a2 == NULL)
 302                 r = 1;
 303         else if (cp->a2)
 304                 if (cp->startline > 0) {
 305                         switch (cp->a2->type) {
 306                         case AT_RELLINE:
 307                                 if (linenum - cp->startline <= cp->a2->u.l)
 308                                         r = 1;
 309                                 else {
 310                                         cp->startline = 0;
 311                                         r = 0;
 312                                 }
 313                                 break;
 314                         default:
 315                                 if (MATCH(cp->a2)) {
 316                                         cp->startline = 0;
 317                                         lastaddr = 1;
 318                                         r = 1;
 319                                 } else if (cp->a2->type == AT_LINE &&
 320                                             linenum > cp->a2->u.l) {
 321                                         /*
 322                                          * We missed the 2nd address due to a
 323                                          * branch, so just close the range and
 324                                          * return false.
 325                                          */
 326                                         cp->startline = 0;
 327                                         r = 0;
 328                                 } else
 329                                         r = 1;
 330                         }
 331                 } else if (cp->a1 && MATCH(cp->a1)) {
 332                         /*
 333                          * If the second address is a number less than or
 334                          * equal to the line number first selected, only
 335                          * one line shall be selected.
 336                          *      -- POSIX 1003.2
 337                          * Likewise if the relative second line address is zero.
 338                          */
 339                         if ((cp->a2->type == AT_LINE &&
 340                             linenum >= cp->a2->u.l) ||
 341                             (cp->a2->type == AT_RELLINE && cp->a2->u.l == 0))
 342                                 lastaddr = 1;
 343                         else {
 344                                 cp->startline = linenum;
 345                         }
 346                         r = 1;
 347                 } else
 348                         r = 0;
 349         else
 350                 r = MATCH(cp->a1);
 351         return (cp->nonsel ? ! r : r);
 352 }
 353
 354 /*
 355  * Reset the sed processor to its initial state.
 356  */
 357 void
 358 resetstate(void)
 359 {
 360         struct s_command *cp;
 361
 362         /*
 363          * Reset all in-range markers.
 364          */
 365         for (cp = prog; cp; cp = cp->code == '{' ? cp->u.c : cp->next)
 366                 if (cp->a2)
 367                         cp->startline = 0;
 368
 369         /*
 370          * Clear out the hold space.
 371          */
 372         cspace(&HS, "", 0, REPLACE);
 373 }
 374
 375 /*
 376  * substitute --
 377  *      Do substitutions in the pattern space.  Currently, we build a
 378  *      copy of the new pattern space in the substitute space structure
 379  *      and then swap them.
 380  */
 381 static int
 382 substitute(struct s_command *cp)
 383 {
 384         SPACE tspace;
 385         regex_t *re;
 386         regoff_t slen;
 387         int lastempty, n;
 388         size_t le = 0;
 389         char *s;
 390
 391         s = ps;
 392         re = cp->u.s->re;
 393         if (re == NULL) {
 394                 if (defpreg != NULL && cp->u.s->maxbref > defpreg->re_nsub) {
 395                         linenum = cp->u.s->linenum;
 396                         errx(1, "%lu: %s: \\%u not defined in the RE",
 397                                         linenum, fname, cp->u.s->maxbref);
 398                 }
 399         }
 400         if (!regexec_e(re, ps, 0, 0, 0, psl))
 401                 return (0);
 402
 403         SS.len = 0;                             /* Clean substitute space. */
 404         slen = psl;
 405         n = cp->u.s->n;
 406         lastempty = 1;
 407
 408         do {
 409                 /* Copy the leading retained string. */
 410                 if (n <= 1 && (match[0].rm_so > le))
 411                         cspace(&SS, s, match[0].rm_so - le, APPEND);
 412
 413                 /* Skip zero-length matches right after other matches. */
 414                 if (lastempty || (match[0].rm_so - le) ||
 415                     match[0].rm_so != match[0].rm_eo) {
 416                         if (n <= 1) {
 417                                 /* Want this match: append replacement. */
 418                                 regsub(&SS, ps, cp->u.s->new);
 419                                 if (n == 1)
 420                                         n = -1;
 421                         } else {
 422                                 /* Want a later match: append original. */
 423                                 if (match[0].rm_eo - le)
 424                                         cspace(&SS, s, match[0].rm_eo - le,
 425                                             APPEND);
 426                                 n--;
 427                         }
 428                 }
 429
 430                 /* Move past this match. */
 431                 s = ps + match[0].rm_eo;
 432                 slen = psl - match[0].rm_eo;
 433                 le = match[0].rm_eo;
 434
 435                 /*
 436                  * After a zero-length match, advance one byte,
 437                  * and at the end of the line, terminate.
 438                  */
 439                 if (match[0].rm_so == match[0].rm_eo) {
 440                         if (*s == '\0' || *s == '\n')
 441                                 slen = -1;
 442                         else
 443                                 slen--;
 444                         if (*s != '\0') {
 445                                 cspace(&SS, s++, 1, APPEND);
 446                                 le++;
 447                         }
 448                         lastempty = 1;
 449                 } else
 450                         lastempty = 0;
 451
 452         } while (n >= 0 && slen >= 0 &&
 453             regexec_e(re, ps, REG_NOTBOL, 0, le, psl));
 454
 455         /* Did not find the requested number of matches. */
 456         if (n > 0)
 457                 return (0);
 458
 459         /* Copy the trailing retained string. */
 460         if (slen > 0)
 461                 cspace(&SS, s, slen, APPEND);
 462
 463         /*
 464          * Swap the substitute space and the pattern space, and make sure
 465          * that any leftover pointers into stdio memory get lost.
 466          */
 467         tspace = PS;
 468         PS = SS;
 469         psanl = tspace.append_newline;
 470         SS = tspace;
 471         SS.space = SS.back;
 472
 473         /* Handle the 'p' flag. */
 474         if (cp->u.s->p)
 475                 OUT();
 476
 477         /* Handle the 'w' flag. */
 478         if (cp->u.s->wfile && !pd) {
 479                 if (cp->u.s->wfd == -1 && (cp->u.s->wfd = open(cp->u.s->wfile,
 480                     O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, DEFFILEMODE)) == -1)
 481                         err(1, "%s", cp->u.s->wfile);
 482                 if (write(cp->u.s->wfd, ps, psl) != (ssize_t)psl ||
 483                     write(cp->u.s->wfd, "\n", 1) != 1)
 484                         err(1, "%s", cp->u.s->wfile);
 485         }
 486         return (1);
 487 }
 488
 489 /*
 490  * do_tr --
 491  *      Perform translation ('y' command) in the pattern space.
 492  */
 493 static void
 494 do_tr(struct s_tr *y)
 495 {
 496         SPACE tmp;
 497         char c, *p;
 498         size_t clen, left;
 499         int i;
 500
 501         if (MB_CUR_MAX == 1) {
 502                 /*
 503                  * Single-byte encoding: perform in-place translation
 504                  * of the pattern space.
 505                  */
 506                 for (p = ps; p < &ps[psl]; p++)
 507                         *p = y->bytetab[(u_char)*p];
 508         } else {
 509                 /*
 510                  * Multi-byte encoding: perform translation into the
 511                  * translation space, then swap the translation and
 512                  * pattern spaces.
 513                  */
 514                 /* Clean translation space. */
 515                 YS.len = 0;
 516                 for (p = ps, left = psl; left > 0; p += clen, left -= clen) {
 517                         if ((c = y->bytetab[(u_char)*p]) != '\0') {
 518                                 cspace(&YS, &c, 1, APPEND);
 519                                 clen = 1;
 520                                 continue;
 521                         }
 522                         for (i = 0; i < y->nmultis; i++)
 523                                 if (left >= y->multis[i].fromlen &&
 524                                     memcmp(p, y->multis[i].from,
 525                                     y->multis[i].fromlen) == 0)
 526                                         break;
 527                         if (i < y->nmultis) {
 528                                 cspace(&YS, y->multis[i].to,
 529                                     y->multis[i].tolen, APPEND);
 530                                 clen = y->multis[i].fromlen;
 531                         } else {
 532                                 cspace(&YS, p, 1, APPEND);
 533                                 clen = 1;
 534                         }
 535                 }
 536                 /* Swap the translation space and the pattern space. */
 537                 tmp = PS;
 538                 PS = YS;
 539                 psanl = tmp.append_newline;
 540                 YS = tmp;
 541                 YS.space = YS.back;
 542         }
 543 }
 544
 545 /*
 546  * Flush append requests.  Always called before reading a line,
 547  * therefore it also resets the substitution done (sdone) flag.
 548  */
 549 static void
 550 flush_appends(void)
 551 {
 552         FILE *f;
 553         int count, i;
 554         char buf[8 * 1024];
 555
 556         for (i = 0; i < appendx; i++)
 557                 switch (appends[i].type) {
 558                 case AP_STRING:
 559                         fwrite(appends[i].s, sizeof(char), appends[i].len,
 560                             outfile);
 561                         break;
 562                 case AP_FILE:
 563                         /*
 564                          * Read files probably shouldn't be cached.  Since
 565                          * it's not an error to read a non-existent file,
 566                          * it's possible that another program is interacting
 567                          * with the sed script through the filesystem.  It
 568                          * would be truly bizarre, but possible.  It's probably
 569                          * not that big a performance win, anyhow.
 570                          */
 571                         if ((f = fopen(appends[i].s, "r")) == NULL)
 572                                 break;
 573                         while ((count = fread(buf, sizeof(char), sizeof(buf), f)))
 574                                 (void)fwrite(buf, sizeof(char), count, outfile);
 575                         (void)fclose(f);
 576                         break;
 577                 }
 578         if (ferror(outfile))
 579                 errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
 580         appendx = sdone = 0;
 581 }
 582
 583 static void
 584 lputs(char *s, size_t len)
 585 {
 586         static const char escapes[] = "\\\a\b\f\r\t\v";
 587         int c, col, width;
 588         const char *p;
 589         struct winsize win;
 590         static int termwidth = -1;
 591         size_t clen, i;
 592         wchar_t wc;
 593         mbstate_t mbs;
 594
 595         if (outfile != stdout)
 596                 termwidth = 60;
 597         if (termwidth == -1) {
 598                 if ((p = getenv("COLUMNS")) && *p != '\0')
 599                         termwidth = atoi(p);
 600                 else if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &win) == 0 &&
 601                     win.ws_col > 0)
 602                         termwidth = win.ws_col;
 603                 else
 604                         termwidth = 60;
 605         }
 606         if (termwidth <= 0)
 607                 termwidth = 1;
 608
 609         memset(&mbs, 0, sizeof(mbs));
 610         col = 0;
 611         while (len != 0) {
 612                 clen = mbrtowc(&wc, s, len, &mbs);
 613                 if (clen == 0)
 614                         clen = 1;
 615                 if (clen == (size_t)-1 || clen == (size_t)-2) {
 616                         wc = (unsigned char)*s;
 617                         clen = 1;
 618                         memset(&mbs, 0, sizeof(mbs));
 619                 }
 620                 if (wc == '\n') {
 621                         if (col + 1 >= termwidth)
 622                                 fprintf(outfile, "\\\n");
 623                         fputc('$', outfile);
 624                         fputc('\n', outfile);
 625                         col = 0;
 626                 } else if (iswprint(wc)) {
 627                         width = wcwidth(wc);
 628                         if (col + width >= termwidth) {
 629                                 fprintf(outfile, "\\\n");
 630                                 col = 0;
 631                         }
 632                         fwrite(s, 1, clen, outfile);
 633                         col += width;
 634                 } else if (wc != L'\0' && (c = wctob(wc)) != EOF &&
 635                     (p = strchr(escapes, c)) != NULL) {
 636                         if (col + 2 >= termwidth) {
 637                                 fprintf(outfile, "\\\n");
 638                                 col = 0;
 639                         }
 640                         fprintf(outfile, "\\%c", "\\abfrtv"[p - escapes]);
 641                         col += 2;
 642                 } else {
 643                         if (col + 4 * clen >= (unsigned)termwidth) {
 644                                 fprintf(outfile, "\\\n");
 645                                 col = 0;
 646                         }
 647                         for (i = 0; i < clen; i++)
 648                                 fprintf(outfile, "\\%03o",
 649                                     (int)(unsigned char)s[i]);
 650                         col += 4 * clen;
 651                 }
 652                 s += clen;
 653                 len -= clen;
 654         }
 655         if (col + 1 >= termwidth)
 656                 fprintf(outfile, "\\\n");
 657         (void)fputc('$', outfile);
 658         (void)fputc('\n', outfile);
 659         if (ferror(outfile))
 660                 errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
 661 }
 662
 663 static int
 664 regexec_e(regex_t *preg, const char *string, int eflags, int nomatch,
 665         size_t start, size_t stop)
 666 {
 667         int eval;
 668
 669         if (preg == NULL) {
 670                 if (defpreg == NULL)
 671                         errx(1, "first RE may not be empty");
 672         } else
 673                 defpreg = preg;
 674
 675         /* Set anchors */
 676         match[0].rm_so = start;
 677         match[0].rm_eo = stop;
 678
 679         eval = regexec(defpreg, string,
 680             nomatch ? 0 : maxnsub + 1, match, eflags | REG_STARTEND);
 681         switch(eval) {
 682         case 0:
 683                 return (1);
 684         case REG_NOMATCH:
 685                 return (0);
 686         }
 687         errx(1, "RE error: %s", strregerror(eval, defpreg));
 688         /* NOTREACHED */
 689 }
 690
 691 /*
 692  * regsub - perform substitutions after a regexp match
 693  * Based on a routine by Henry Spencer
 694  */
 695 static void
 696 regsub(SPACE *sp, char *string, char *src)
 697 {
 698         int len, no;
 699         char c, *dst;
 700
 701 #define NEEDSP(reqlen)                                                  \
 702         /* XXX What is the +1 for? */                                   \
 703         if (sp->len + (reqlen) + 1 >= sp->blen) {                       \
 704                 sp->blen += (reqlen) + 1024;                            \
 705                 if ((sp->space = sp->back = realloc(sp->back, sp->blen)) \
 706                     == NULL)                                            \
 707                         err(1, "realloc");                              \
 708                 dst = sp->space + sp->len;                              \
 709         }
 710
 711         dst = sp->space + sp->len;
 712         while ((c = *src++) != '\0') {
 713                 if (c == '&')
 714                         no = 0;
 715                 else if (c == '\\' && isdigit((unsigned char)*src))
 716                         no = *src++ - '0';
 717                 else
 718                         no = -1;
 719                 if (no < 0) {           /* Ordinary character. */
 720                         if (c == '\\' && (*src == '\\' || *src == '&'))
 721                                 c = *src++;
 722                         NEEDSP(1);
 723                         *dst++ = c;
 724                         ++sp->len;
 725                 } else if (match[no].rm_so != -1 && match[no].rm_eo != -1) {
 726                         len = match[no].rm_eo - match[no].rm_so;
 727                         NEEDSP(len);
 728                         memmove(dst, string + match[no].rm_so, len);
 729                         dst += len;
 730                         sp->len += len;
 731                 }
 732         }
 733         NEEDSP(1);
 734         *dst = '\0';
 735 }
 736
 737 /*
 738  * cspace --
 739  *      Concatenate space: append the source space to the destination space,
 740  *      allocating new space as necessary.
 741  */
 742 void
 743 cspace(SPACE *sp, const char *p, size_t len, enum e_spflag spflag)
 744 {
 745         size_t tlen;
 746
 747         /* Make sure SPACE has enough memory and ramp up quickly. */
 748         tlen = sp->len + len + 1;
 749         if (tlen > sp->blen) {
 750                 sp->blen = tlen + 1024;
 751                 if ((sp->space = sp->back = realloc(sp->back, sp->blen)) ==
 752                     NULL)
 753                         err(1, "realloc");
 754         }
 755
 756         if (spflag == REPLACE)
 757                 sp->len = 0;
 758
 759         memmove(sp->space + sp->len, p, len);
 760
 761         sp->space[sp->len += len] = '\0';
 762 }
 763
 764 /*
 765  * Close all cached opened files and report any errors
 766  */
 767 void
 768 cfclose(struct s_command *cp, struct s_command *end)
 769 {
 770
 771         for (; cp != end; cp = cp->next)
 772                 switch(cp->code) {
 773                 case 's':
 774                         if (cp->u.s->wfd != -1 && close(cp->u.s->wfd))
 775                                 err(1, "%s", cp->u.s->wfile);
 776                         cp->u.s->wfd = -1;
 777                         break;
 778                 case 'w':
 779                         if (cp->u.fd != -1 && close(cp->u.fd))
 780                                 err(1, "%s", cp->t);
 781                         cp->u.fd = -1;
 782                         break;
 783                 case '{':
 784                         cfclose(cp->u.c, cp->next);
 785                         break;
 786                 }
 787 }