usr.bin/sed/process.c

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