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