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  * @(#)process.c        8.6 (Berkeley) 4/20/94
  34  * $FreeBSD: head/usr.bin/sed/process.c 277802 2015-01-27 18:58:24Z pfg $
  35  */
  36
  37 #include <sys/types.h>
  38 #include <sys/stat.h>
  39 #include <sys/ioctl.h>
  40 #include <sys/uio.h>
  41
  42 #include <ctype.h>
  43 #include <err.h>
  44 #include <errno.h>
  45 #include <fcntl.h>
  46 #include <limits.h>
  47 #include <regex.h>
  48 #include <stdio.h>
  49 #include <stdlib.h>
  50 #include <string.h>
  51 #include <unistd.h>
  52 #include <wchar.h>
  53 #include <wctype.h>
  54
  55 #include "defs.h"
  56 #include "extern.h"
  57
  58 static SPACE HS, PS, SS, YS;
  59 #define pd              PS.deleted
  60 #define ps              PS.space
  61 #define psl             PS.len
  62 #define psanl           PS.append_newline
  63 #define hs              HS.space
  64 #define hsl             HS.len
  65
  66 static inline int        applies(struct s_command *);
  67 static void              do_tr(struct s_tr *);
  68 static void              flush_appends(void);
  69 static void              lputs(char *, size_t);
  70 static int               regexec_e(regex_t *, const char *, int, int, size_t);
  71 static void              regsub(SPACE *, char *, char *);
  72 static int               substitute(struct s_command *);
  73
  74 struct s_appends *appends;      /* Array of pointers to strings to append. */
  75 static int appendx;             /* Index into appends array. */
  76 int appendnum;                  /* Size of appends array. */
  77
  78 static int lastaddr;            /* Set by applies if last address of a range. */
  79 static int sdone;               /* If any substitutes since last line input. */
  80                                 /* Iov structure for 'w' commands. */
  81 static regex_t *defpreg;
  82 size_t maxnsub;
  83 regmatch_t *match;
  84
  85 #define OUT() do {                                                      \
  86         fwrite(ps, 1, psl, outfile);                                    \
  87         if (psanl) fputc('\n', outfile);                                \
  88 } while (0)
  89
  90 void
  91 process(void)
  92 {
  93         struct s_command *cp;
  94         SPACE tspace;
  95         size_t oldpsl = 0;
  96         char *p;
  97         int oldpsanl;
  98
  99         p = NULL;
 100
 101         for (linenum = 0; mf_fgets(&PS, REPLACE);) {
 102                 pd = 0;
 103 top:
 104                 cp = prog;
 105 redirect:
 106                 while (cp != NULL) {
 107                         if (!applies(cp)) {
 108                                 cp = cp->next;
 109                                 continue;
 110                         }
 111                         switch (cp->code) {
 112                         case '{':
 113                                 cp = cp->u.c;
 114                                 goto redirect;
 115                         case 'a':
 116                                 if (appendx >= appendnum)
 117                                         if ((appends = realloc(appends,
 118                                             sizeof(struct s_appends) *
 119                                             (appendnum *= 2))) == NULL)
 120                                                 err(1, "realloc");
 121                                 appends[appendx].type = AP_STRING;
 122                                 appends[appendx].s = cp->t;
 123                                 appends[appendx].len = strlen(cp->t);
 124                                 appendx++;
 125                                 break;
 126                         case 'b':
 127                                 cp = cp->u.c;
 128                                 goto redirect;
 129                         case 'c':
 130                                 pd = 1;
 131                                 psl = 0;
 132                                 if (cp->a2 == NULL || lastaddr || lastline())
 133                                         (void)fprintf(outfile, "%s", cp->t);
 134                                 break;
 135                         case 'd':
 136                                 pd = 1;
 137                                 goto new;
 138                         case 'D':
 139                                 if (pd)
 140                                         goto new;
 141                                 if (psl == 0 ||
 142                                     (p = memchr(ps, '\n', psl)) == NULL) {
 143                                         pd = 1;
 144                                         goto new;
 145                                 } else {
 146                                         psl -= (p + 1) - ps;
 147                                         memmove(ps, p + 1, psl);
 148                                         goto top;
 149                                 }
 150                         case 'g':
 151                                 cspace(&PS, hs, hsl, REPLACE);
 152                                 break;
 153                         case 'G':
 154                                 cspace(&PS, "\n", 1, APPEND);
 155                                 cspace(&PS, hs, hsl, APPEND);
 156                                 break;
 157                         case 'h':
 158                                 cspace(&HS, ps, psl, REPLACE);
 159                                 break;
 160                         case 'H':
 161                                 cspace(&HS, "\n", 1, APPEND);
 162                                 cspace(&HS, ps, psl, APPEND);
 163                                 break;
 164                         case 'i':
 165                                 (void)fprintf(outfile, "%s", cp->t);
 166                                 break;
 167                         case 'l':
 168                                 lputs(ps, psl);
 169                                 break;
 170                         case 'n':
 171                                 if (!nflag && !pd)
 172                                         OUT();
 173                                 flush_appends();
 174                                 if (!mf_fgets(&PS, REPLACE))
 175                                         exit(0);
 176                                 pd = 0;
 177                                 break;
 178                         case 'N':
 179                                 flush_appends();
 180                                 cspace(&PS, "\n", 1, APPEND);
 181                                 if (!mf_fgets(&PS, APPEND))
 182                                         exit(0);
 183                                 break;
 184                         case 'p':
 185                                 if (pd)
 186                                         break;
 187                                 OUT();
 188                                 break;
 189                         case 'P':
 190                                 if (pd)
 191                                         break;
 192                                 if ((p = memchr(ps, '\n', psl)) != NULL) {
 193                                         oldpsl = psl;
 194                                         oldpsanl = psanl;
 195                                         psl = p - ps;
 196                                         psanl = 1;
 197                                 }
 198                                 OUT();
 199                                 if (p != NULL) {
 200                                         psl = oldpsl;
 201                                         psanl = oldpsanl;
 202                                 }
 203                                 break;
 204                         case 'q':
 205                                 if (!nflag && !pd)
 206                                         OUT();
 207                                 flush_appends();
 208                                 exit(0);
 209                         case 'r':
 210                                 if (appendx >= appendnum)
 211                                         if ((appends = realloc(appends,
 212                                             sizeof(struct s_appends) *
 213                                             (appendnum *= 2))) == NULL)
 214                                                 err(1, "realloc");
 215                                 appends[appendx].type = AP_FILE;
 216                                 appends[appendx].s = cp->t;
 217                                 appends[appendx].len = strlen(cp->t);
 218                                 appendx++;
 219                                 break;
 220                         case 's':
 221                                 sdone |= substitute(cp);
 222                                 break;
 223                         case 't':
 224                                 if (sdone) {
 225                                         sdone = 0;
 226                                         cp = cp->u.c;
 227                                         goto redirect;
 228                                 }
 229                                 break;
 230                         case 'w':
 231                                 if (pd)
 232                                         break;
 233                                 if (cp->u.fd == -1 && (cp->u.fd = open(cp->t,
 234                                     O_WRONLY|O_APPEND|O_CREAT|O_TRUNC,
 235                                     DEFFILEMODE)) == -1)
 236                                         err(1, "%s", cp->t);
 237                                 if (write(cp->u.fd, ps, psl) != (ssize_t)psl ||
 238                                     write(cp->u.fd, "\n", 1) != 1)
 239                                         err(1, "%s", cp->t);
 240                                 break;
 241                         case 'x':
 242                                 /*
 243                                  * If the hold space is null, make it empty
 244                                  * but not null.  Otherwise the pattern space
 245                                  * will become null after the swap, which is
 246                                  * an abnormal condition.
 247                                  */
 248                                 if (hs == NULL)
 249                                         cspace(&HS, "", 0, REPLACE);
 250                                 tspace = PS;
 251                                 PS = HS;
 252                                 psanl = tspace.append_newline;
 253                                 HS = tspace;
 254                                 break;
 255                         case 'y':
 256                                 if (pd || psl == 0)
 257                                         break;
 258                                 do_tr(cp->u.y);
 259                                 break;
 260                         case ':':
 261                         case '}':
 262                                 break;
 263                         case '=':
 264                                 (void)fprintf(outfile, "%lu\n", linenum);
 265                         }
 266                         cp = cp->next;
 267                 } /* for all cp */
 268
 269 new:            if (!nflag && !pd)
 270                         OUT();
 271                 flush_appends();
 272         } /* for all lines */
 273 }
 274
 275 /*
 276  * TRUE if the address passed matches the current program state
 277  * (lastline, linenumber, ps).
 278  */
 279 #define MATCH(a)                                                        \
 280         ((a)->type == AT_RE ? regexec_e((a)->u.r, ps, 0, 1, psl) :      \
 281             (a)->type == AT_LINE ? linenum == (a)->u.l : lastline())
 282
 283 /*
 284  * Return TRUE if the command applies to the current line.  Sets the start
 285  * line for process ranges.  Interprets the non-select (``!'') flag.
 286  */
 287 static inline int
 288 applies(struct s_command *cp)
 289 {
 290         int r;
 291
 292         lastaddr = 0;
 293         if (cp->a1 == NULL && cp->a2 == NULL)
 294                 r = 1;
 295         else if (cp->a2)
 296                 if (cp->startline > 0) {
 297                         switch (cp->a2->type) {
 298                         case AT_RELLINE:
 299                                 if (linenum - cp->startline <= cp->a2->u.l)
 300                                         r = 1;
 301                                 else {
 302                                         cp->startline = 0;
 303                                         r = 0;
 304                                 }
 305                                 break;
 306                         default:
 307                                 if (MATCH(cp->a2)) {
 308                                         cp->startline = 0;
 309                                         lastaddr = 1;
 310                                         r = 1;
 311                                 } else if (cp->a2->type == AT_LINE &&
 312                                             linenum > cp->a2->u.l) {
 313                                         /*
 314                                          * We missed the 2nd address due to a
 315                                          * branch, so just close the range and
 316                                          * return false.
 317                                          */
 318                                         cp->startline = 0;
 319                                         r = 0;
 320                                 } else
 321                                         r = 1;
 322                         }
 323                 } else if (cp->a1 && MATCH(cp->a1)) {
 324                         /*
 325                          * If the second address is a number less than or
 326                          * equal to the line number first selected, only
 327                          * one line shall be selected.
 328                          *      -- POSIX 1003.2
 329                          * Likewise if the relative second line address is zero.
 330                          */
 331                         if ((cp->a2->type == AT_LINE &&
 332                             linenum >= cp->a2->u.l) ||
 333                             (cp->a2->type == AT_RELLINE && cp->a2->u.l == 0))
 334                                 lastaddr = 1;
 335                         else {
 336                                 cp->startline = linenum;
 337                         }
 338                         r = 1;
 339                 } else
 340                         r = 0;
 341         else
 342                 r = MATCH(cp->a1);
 343         return (cp->nonsel ? ! r : r);
 344 }
 345
 346 /*
 347  * Reset the sed processor to its initial state.
 348  */
 349 void
 350 resetstate(void)
 351 {
 352         struct s_command *cp;
 353
 354         /*
 355          * Reset all in-range markers.
 356          */
 357         for (cp = prog; cp; cp = cp->code == '{' ? cp->u.c : cp->next)
 358                 if (cp->a2)
 359                         cp->startline = 0;
 360
 361         /*
 362          * Clear out the hold space.
 363          */
 364         cspace(&HS, "", 0, REPLACE);
 365 }
 366
 367 /*
 368  * substitute --
 369  *      Do substitutions in the pattern space.  Currently, we build a
 370  *      copy of the new pattern space in the substitute space structure
 371  *      and then swap them.
 372  */
 373 static int
 374 substitute(struct s_command *cp)
 375 {
 376         SPACE tspace;
 377         regex_t *re;
 378         regoff_t re_off, slen;
 379         int lastempty, n;
 380         char *s;
 381
 382         s = ps;
 383         re = cp->u.s->re;
 384         if (re == NULL) {
 385                 if (defpreg != NULL && cp->u.s->maxbref > defpreg->re_nsub) {
 386                         linenum = cp->u.s->linenum;
 387                         errx(1, "%lu: %s: \\%u not defined in the RE",
 388                                         linenum, fname, cp->u.s->maxbref);
 389                 }
 390         }
 391         if (!regexec_e(re, s, 0, 0, psl))
 392                 return (0);
 393
 394         SS.len = 0;                             /* Clean substitute space. */
 395         slen = psl;
 396         n = cp->u.s->n;
 397         lastempty = 1;
 398
 399         switch (n) {
 400         case 0:                                 /* Global */
 401                 do {
 402                         if (lastempty || match[0].rm_so != match[0].rm_eo) {
 403                                 /* Locate start of replaced string. */
 404                                 re_off = match[0].rm_so;
 405                                 /* Copy leading retained string. */
 406                                 cspace(&SS, s, re_off, APPEND);
 407                                 /* Add in regular expression. */
 408                                 regsub(&SS, s, cp->u.s->new);
 409                         }
 410
 411                         /* Move past this match. */
 412                         if (match[0].rm_so != match[0].rm_eo) {
 413                                 s += match[0].rm_eo;
 414                                 slen -= match[0].rm_eo;
 415                                 lastempty = 0;
 416                         } else {
 417                                 if (match[0].rm_so < slen)
 418                                         cspace(&SS, s + match[0].rm_so, 1,
 419                                             APPEND);
 420                                 s += match[0].rm_so + 1;
 421                                 slen -= match[0].rm_so + 1;
 422                                 lastempty = 1;
 423                         }
 424                 } while (slen >= 0 && regexec_e(re, s, REG_NOTBOL, 0, slen));
 425                 /* Copy trailing retained string. */
 426                 if (slen > 0)
 427                         cspace(&SS, s, slen, APPEND);
 428                 break;
 429         default:                                /* Nth occurrence */
 430                 while (--n) {
 431                         if (match[0].rm_eo == match[0].rm_so)
 432                                 match[0].rm_eo = match[0].rm_so + 1;
 433                         s += match[0].rm_eo;
 434                         slen -= match[0].rm_eo;
 435                         if (slen < 0)
 436                                 return (0);
 437                         if (!regexec_e(re, s, REG_NOTBOL, 0, slen))
 438                                 return (0);
 439                 }
 440                 /* FALLTHROUGH */
 441         case 1:                                 /* 1st occurrence */
 442                 /* Locate start of replaced string. */
 443                 re_off = match[0].rm_so + (s - ps);
 444                 /* Copy leading retained string. */
 445                 cspace(&SS, ps, re_off, APPEND);
 446                 /* Add in regular expression. */
 447                 regsub(&SS, s, cp->u.s->new);
 448                 /* Copy trailing retained string. */
 449                 s += match[0].rm_eo;
 450                 slen -= match[0].rm_eo;
 451                 cspace(&SS, s, slen, APPEND);
 452                 break;
 453         }
 454
 455         /*
 456          * Swap the substitute space and the pattern space, and make sure
 457          * that any leftover pointers into stdio memory get lost.
 458          */
 459         tspace = PS;
 460         PS = SS;
 461         psanl = tspace.append_newline;
 462         SS = tspace;
 463         SS.space = SS.back;
 464
 465         /* Handle the 'p' flag. */
 466         if (cp->u.s->p)
 467                 OUT();
 468
 469         /* Handle the 'w' flag. */
 470         if (cp->u.s->wfile && !pd) {
 471                 if (cp->u.s->wfd == -1 && (cp->u.s->wfd = open(cp->u.s->wfile,
 472                     O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, DEFFILEMODE)) == -1)
 473                         err(1, "%s", cp->u.s->wfile);
 474                 if (write(cp->u.s->wfd, ps, psl) != (ssize_t)psl ||
 475                     write(cp->u.s->wfd, "\n", 1) != 1)
 476                         err(1, "%s", cp->u.s->wfile);
 477         }
 478         return (1);
 479 }
 480
 481 /*
 482  * do_tr --
 483  *      Perform translation ('y' command) in the pattern space.
 484  */
 485 static void
 486 do_tr(struct s_tr *y)
 487 {
 488         SPACE tmp;
 489         char c, *p;
 490         size_t clen, left;
 491         int i;
 492
 493         if (MB_CUR_MAX == 1) {
 494                 /*
 495                  * Single-byte encoding: perform in-place translation
 496                  * of the pattern space.
 497                  */
 498                 for (p = ps; p < &ps[psl]; p++)
 499                         *p = y->bytetab[(u_char)*p];
 500         } else {
 501                 /*
 502                  * Multi-byte encoding: perform translation into the
 503                  * translation space, then swap the translation and
 504                  * pattern spaces.
 505                  */
 506                 /* Clean translation space. */
 507                 YS.len = 0;
 508                 for (p = ps, left = psl; left > 0; p += clen, left -= clen) {
 509                         if ((c = y->bytetab[(u_char)*p]) != '\0') {
 510                                 cspace(&YS, &c, 1, APPEND);
 511                                 clen = 1;
 512                                 continue;
 513                         }
 514                         for (i = 0; i < y->nmultis; i++)
 515                                 if (left >= y->multis[i].fromlen &&
 516                                     memcmp(p, y->multis[i].from,
 517                                     y->multis[i].fromlen) == 0)
 518                                         break;
 519                         if (i < y->nmultis) {
 520                                 cspace(&YS, y->multis[i].to,
 521                                     y->multis[i].tolen, APPEND);
 522                                 clen = y->multis[i].fromlen;
 523                         } else {
 524                                 cspace(&YS, p, 1, APPEND);
 525                                 clen = 1;
 526                         }
 527                 }
 528                 /* Swap the translation space and the pattern space. */
 529                 tmp = PS;
 530                 PS = YS;
 531                 psanl = tmp.append_newline;
 532                 YS = tmp;
 533                 YS.space = YS.back;
 534         }
 535 }
 536
 537 /*
 538  * Flush append requests.  Always called before reading a line,
 539  * therefore it also resets the substitution done (sdone) flag.
 540  */
 541 static void
 542 flush_appends(void)
 543 {
 544         FILE *f;
 545         int count, i;
 546         char buf[8 * 1024];
 547
 548         for (i = 0; i < appendx; i++)
 549                 switch (appends[i].type) {
 550                 case AP_STRING:
 551                         fwrite(appends[i].s, sizeof(char), appends[i].len,
 552                             outfile);
 553                         break;
 554                 case AP_FILE:
 555                         /*
 556                          * Read files probably shouldn't be cached.  Since
 557                          * it's not an error to read a non-existent file,
 558                          * it's possible that another program is interacting
 559                          * with the sed script through the filesystem.  It
 560                          * would be truly bizarre, but possible.  It's probably
 561                          * not that big a performance win, anyhow.
 562                          */
 563                         if ((f = fopen(appends[i].s, "r")) == NULL)
 564                                 break;
 565                         while ((count = fread(buf, sizeof(char), sizeof(buf), f)))
 566                                 (void)fwrite(buf, sizeof(char), count, outfile);
 567                         (void)fclose(f);
 568                         break;
 569                 }
 570         if (ferror(outfile))
 571                 errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
 572         appendx = sdone = 0;
 573 }
 574
 575 static void
 576 lputs(char *s, size_t len)
 577 {
 578         static const char escapes[] = "\\\a\b\f\r\t\v";
 579         int c, col, width;
 580         const char *p;
 581         struct winsize win;
 582         static int termwidth = -1;
 583         size_t clen, i;
 584         wchar_t wc;
 585         mbstate_t mbs;
 586
 587         if (outfile != stdout)
 588                 termwidth = 60;
 589         if (termwidth == -1) {
 590                 if ((p = getenv("COLUMNS")) && *p != '\0')
 591                         termwidth = atoi(p);
 592                 else if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &win) == 0 &&
 593                     win.ws_col > 0)
 594                         termwidth = win.ws_col;
 595                 else
 596                         termwidth = 60;
 597         }
 598         if (termwidth <= 0)
 599                 termwidth = 1;
 600
 601         memset(&mbs, 0, sizeof(mbs));
 602         col = 0;
 603         while (len != 0) {
 604                 clen = mbrtowc(&wc, s, len, &mbs);
 605                 if (clen == 0)
 606                         clen = 1;
 607                 if (clen == (size_t)-1 || clen == (size_t)-2) {
 608                         wc = (unsigned char)*s;
 609                         clen = 1;
 610                         memset(&mbs, 0, sizeof(mbs));
 611                 }
 612                 if (wc == '\n') {
 613                         if (col + 1 >= termwidth)
 614                                 fprintf(outfile, "\\\n");
 615                         fputc('$', outfile);
 616                         fputc('\n', outfile);
 617                         col = 0;
 618                 } else if (iswprint(wc)) {
 619                         width = wcwidth(wc);
 620                         if (col + width >= termwidth) {
 621                                 fprintf(outfile, "\\\n");
 622                                 col = 0;
 623                         }
 624                         fwrite(s, 1, clen, outfile);
 625                         col += width;
 626                 } else if (wc != L'\0' && (c = wctob(wc)) != EOF &&
 627                     (p = strchr(escapes, c)) != NULL) {
 628                         if (col + 2 >= termwidth) {
 629                                 fprintf(outfile, "\\\n");
 630                                 col = 0;
 631                         }
 632                         fprintf(outfile, "\\%c", "\\abfrtv"[p - escapes]);
 633                         col += 2;
 634                 } else {
 635                         if (col + 4 * clen >= (unsigned)termwidth) {
 636                                 fprintf(outfile, "\\\n");
 637                                 col = 0;
 638                         }
 639                         for (i = 0; i < clen; i++)
 640                                 fprintf(outfile, "\\%03o",
 641                                     (int)(unsigned char)s[i]);
 642                         col += 4 * clen;
 643                 }
 644                 s += clen;
 645                 len -= clen;
 646         }
 647         if (col + 1 >= termwidth)
 648                 fprintf(outfile, "\\\n");
 649         (void)fputc('$', outfile);
 650         (void)fputc('\n', outfile);
 651         if (ferror(outfile))
 652                 errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
 653 }
 654
 655 static int
 656 regexec_e(regex_t *preg, const char *string, int eflags, int nomatch,
 657         size_t slen)
 658 {
 659         int eval;
 660
 661         if (preg == NULL) {
 662                 if (defpreg == NULL)
 663                         errx(1, "first RE may not be empty");
 664         } else
 665                 defpreg = preg;
 666
 667         /* Set anchors */
 668         match[0].rm_so = 0;
 669         match[0].rm_eo = slen;
 670
 671         eval = regexec(defpreg, string,
 672             nomatch ? 0 : maxnsub + 1, match, eflags | REG_STARTEND);
 673         switch(eval) {
 674         case 0:
 675                 return (1);
 676         case REG_NOMATCH:
 677                 return (0);
 678         }
 679         errx(1, "RE error: %s", strregerror(eval, defpreg));
 680         /* NOTREACHED */
 681 }
 682
 683 /*
 684  * regsub - perform substitutions after a regexp match
 685  * Based on a routine by Henry Spencer
 686  */
 687 static void
 688 regsub(SPACE *sp, char *string, char *src)
 689 {
 690         int len, no;
 691         char c, *dst;
 692
 693 #define NEEDSP(reqlen)                                                  \
 694         /* XXX What is the +1 for? */                                   \
 695         if (sp->len + (reqlen) + 1 >= sp->blen) {                       \
 696                 sp->blen += (reqlen) + 1024;                            \
 697                 if ((sp->space = sp->back = realloc(sp->back, sp->blen)) \
 698                     == NULL)                                            \
 699                         err(1, "realloc");                              \
 700                 dst = sp->space + sp->len;                              \
 701         }
 702
 703         dst = sp->space + sp->len;
 704         while ((c = *src++) != '\0') {
 705                 if (c == '&')
 706                         no = 0;
 707                 else if (c == '\\' && isdigit((unsigned char)*src))
 708                         no = *src++ - '0';
 709                 else
 710                         no = -1;
 711                 if (no < 0) {           /* Ordinary character. */
 712                         if (c == '\\' && (*src == '\\' || *src == '&'))
 713                                 c = *src++;
 714                         NEEDSP(1);
 715                         *dst++ = c;
 716                         ++sp->len;
 717                 } else if (match[no].rm_so != -1 && match[no].rm_eo != -1) {
 718                         len = match[no].rm_eo - match[no].rm_so;
 719                         NEEDSP(len);
 720                         memmove(dst, string + match[no].rm_so, len);
 721                         dst += len;
 722                         sp->len += len;
 723                 }
 724         }
 725         NEEDSP(1);
 726         *dst = '\0';
 727 }
 728
 729 /*
 730  * cspace --
 731  *      Concatenate space: append the source space to the destination space,
 732  *      allocating new space as necessary.
 733  */
 734 void
 735 cspace(SPACE *sp, const char *p, size_t len, enum e_spflag spflag)
 736 {
 737         size_t tlen;
 738
 739         /* Make sure SPACE has enough memory and ramp up quickly. */
 740         tlen = sp->len + len + 1;
 741         if (tlen > sp->blen) {
 742                 sp->blen = tlen + 1024;
 743                 if ((sp->space = sp->back = realloc(sp->back, sp->blen)) ==
 744                     NULL)
 745                         err(1, "realloc");
 746         }
 747
 748         if (spflag == REPLACE)
 749                 sp->len = 0;
 750
 751         memmove(sp->space + sp->len, p, len);
 752
 753         sp->space[sp->len += len] = '\0';
 754 }
 755
 756 /*
 757  * Close all cached opened files and report any errors
 758  */
 759 void
 760 cfclose(struct s_command *cp, struct s_command *end)
 761 {
 762
 763         for (; cp != end; cp = cp->next)
 764                 switch(cp->code) {
 765                 case 's':
 766                         if (cp->u.s->wfd != -1 && close(cp->u.s->wfd))
 767                                 err(1, "%s", cp->u.s->wfile);
 768                         cp->u.s->wfd = -1;
 769                         break;
 770                 case 'w':
 771                         if (cp->u.fd != -1 && close(cp->u.fd))
 772                                 err(1, "%s", cp->t);
 773                         cp->u.fd = -1;
 774                         break;
 775                 case '{':
 776                         cfclose(cp->u.c, cp->next);
 777                         break;
 778                 }
 779 }