mansearch.c

   1 /*      $OpenBSD: mansearch.c,v 1.50 2016/07/09 15:23:36 schwarze Exp $ */
   2 /*
   3  * Copyright (c) 2012 Kristaps Dzonsons <kristaps@bsd.lv>
   4  * Copyright (c) 2013, 2014, 2015, 2016 Ingo Schwarze <schwarze@openbsd.org>
   5  *
   6  * Permission to use, copy, modify, and distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18 #include "config.h"
  19
  20 #include <sys/mman.h>
  21 #include <sys/types.h>
  22
  23 #include <assert.h>
  24 #include <err.h>
  25 #include <errno.h>
  26 #include <fcntl.h>
  27 #include <glob.h>
  28 #include <limits.h>
  29 #include <regex.h>
  30 #include <stdio.h>
  31 #include <stdint.h>
  32 #include <stddef.h>
  33 #include <stdlib.h>
  34 #include <string.h>
  35 #include <unistd.h>
  36
  37 #include "mandoc.h"
  38 #include "mandoc_aux.h"
  39 #include "mandoc_ohash.h"
  40 #include "manconf.h"
  41 #include "mansearch.h"
  42 #include "dbm.h"
  43
  44 struct  expr {
  45         /* Used for terms: */
  46         struct dbm_match match;   /* Match type and expression. */
  47         uint64_t         bits;    /* Type mask. */
  48         /* Used for OR and AND groups: */
  49         struct expr     *next;    /* Next child in the parent group. */
  50         struct expr     *child;   /* First child in this group. */
  51         enum { EXPR_TERM, EXPR_OR, EXPR_AND } type;
  52 };
  53
  54 const char *const mansearch_keynames[KEY_MAX] = {
  55         "arch", "sec",  "Xr",   "Ar",   "Fa",   "Fl",   "Dv",   "Fn",
  56         "Ic",   "Pa",   "Cm",   "Li",   "Em",   "Cd",   "Va",   "Ft",
  57         "Tn",   "Er",   "Ev",   "Sy",   "Sh",   "In",   "Ss",   "Ox",
  58         "An",   "Mt",   "St",   "Bx",   "At",   "Nx",   "Fx",   "Lk",
  59         "Ms",   "Bsx",  "Dx",   "Rs",   "Vt",   "Lb",   "Nm",   "Nd"
  60 };
  61
  62
  63 static  struct ohash    *manmerge(struct expr *, struct ohash *);
  64 static  struct ohash    *manmerge_term(struct expr *, struct ohash *);
  65 static  struct ohash    *manmerge_or(struct expr *, struct ohash *);
  66 static  struct ohash    *manmerge_and(struct expr *, struct ohash *);
  67 static  char            *buildnames(const struct dbm_page *);
  68 static  char            *buildoutput(size_t, int32_t);
  69 static  size_t           lstlen(const char *);
  70 static  void             lstcat(char *, size_t *, const char *);
  71 static  int              lstmatch(const char *, const char *);
  72 static  struct expr     *exprcomp(const struct mansearch *,
  73                                 int, char *[], int *);
  74 static  struct expr     *expr_and(const struct mansearch *,
  75                                 int, char *[], int *);
  76 static  struct expr     *exprterm(const struct mansearch *,
  77                                 int, char *[], int *);
  78 static  void             exprfree(struct expr *);
  79 static  int              manpage_compare(const void *, const void *);
  80
  81
  82 int
  83 mansearch(const struct mansearch *search,
  84                 const struct manpaths *paths,
  85                 int argc, char *argv[],
  86                 struct manpage **res, size_t *sz)
  87 {
  88         char             buf[PATH_MAX];
  89         struct dbm_res  *rp;
  90         struct expr     *e;
  91         struct dbm_page *page;
  92         struct manpage  *mpage;
  93         struct ohash    *htab;
  94         size_t           cur, i, maxres, outkey;
  95         unsigned int     slot;
  96         int              argi, chdir_status, getcwd_status, im;
  97
  98         argi = 0;
  99         if ((e = exprcomp(search, argc, argv, &argi)) == NULL) {
 100                 *sz = 0;
 101                 return 0;
 102         }
 103
 104         cur = maxres = 0;
 105         *res = NULL;
 106
 107         outkey = KEY_Nd;
 108         if (search->outkey != NULL)
 109                 for (im = 0; im < KEY_MAX; im++)
 110                         if (0 == strcasecmp(search->outkey,
 111                             mansearch_keynames[im])) {
 112                                 outkey = im;
 113                                 break;
 114                         }
 115
 116         /*
 117          * Remember the original working directory, if possible.
 118          * This will be needed if the second or a later directory
 119          * is given as a relative path.
 120          * Do not error out if the current directory is not
 121          * searchable: Maybe it won't be needed after all.
 122          */
 123
 124         if (getcwd(buf, PATH_MAX) == NULL) {
 125                 getcwd_status = 0;
 126                 (void)strlcpy(buf, strerror(errno), sizeof(buf));
 127         } else
 128                 getcwd_status = 1;
 129
 130         /*
 131          * Loop over the directories (containing databases) for us to
 132          * search.
 133          * Don't let missing/bad databases/directories phase us.
 134          * In each, try to open the resident database and, if it opens,
 135          * scan it for our match expression.
 136          */
 137
 138         chdir_status = 0;
 139         for (i = 0; i < paths->sz; i++) {
 140                 if (chdir_status && paths->paths[i][0] != '/') {
 141                         if ( ! getcwd_status) {
 142                                 warnx("%s: getcwd: %s", paths->paths[i], buf);
 143                                 continue;
 144                         } else if (chdir(buf) == -1) {
 145                                 warn("%s", buf);
 146                                 continue;
 147                         }
 148                 }
 149                 if (chdir(paths->paths[i]) == -1) {
 150                         warn("%s", paths->paths[i]);
 151                         continue;
 152                 }
 153                 chdir_status = 1;
 154
 155                 if (dbm_open(MANDOC_DB) == -1) {
 156                         warn("%s/%s", paths->paths[i], MANDOC_DB);
 157                         continue;
 158                 }
 159
 160                 if ((htab = manmerge(e, NULL)) == NULL) {
 161                         dbm_close();
 162                         continue;
 163                 }
 164
 165                 for (rp = ohash_first(htab, &slot); rp != NULL;
 166                     rp = ohash_next(htab, &slot)) {
 167                         page = dbm_page_get(rp->page);
 168
 169                         if (lstmatch(search->sec, page->sect) == 0 ||
 170                             lstmatch(search->arch, page->arch) == 0)
 171                                 continue;
 172
 173                         if (cur + 1 > maxres) {
 174                                 maxres += 1024;
 175                                 *res = mandoc_reallocarray(*res,
 176                                     maxres, sizeof(**res));
 177                         }
 178                         mpage = *res + cur;
 179                         mandoc_asprintf(&mpage->file, "%s/%s",
 180                             paths->paths[i], page->file + 1);
 181                         mpage->names = buildnames(page);
 182                         mpage->output = (int)outkey == KEY_Nd ?
 183                             mandoc_strdup(page->desc) :
 184                             buildoutput(outkey, page->addr);
 185                         mpage->ipath = i;
 186                         mpage->bits = rp->bits;
 187                         mpage->sec = *page->sect - '0';
 188                         if (mpage->sec < 0 || mpage->sec > 9)
 189                                 mpage->sec = 10;
 190                         mpage->form = *page->file;
 191                         free(rp);
 192                         cur++;
 193                 }
 194                 ohash_delete(htab);
 195                 free(htab);
 196                 dbm_close();
 197
 198                 /*
 199                  * In man(1) mode, prefer matches in earlier trees
 200                  * over matches in later trees.
 201                  */
 202
 203                 if (cur && search->firstmatch)
 204                         break;
 205         }
 206         qsort(*res, cur, sizeof(struct manpage), manpage_compare);
 207         if (chdir_status && getcwd_status && chdir(buf) == -1)
 208                 warn("%s", buf);
 209         exprfree(e);
 210         *sz = cur;
 211         return 1;
 212 }
 213
 214 /*
 215  * Merge the results for the expression tree rooted at e
 216  * into the the result list htab.
 217  */
 218 static struct ohash *
 219 manmerge(struct expr *e, struct ohash *htab)
 220 {
 221         switch (e->type) {
 222         case EXPR_TERM:
 223                 return manmerge_term(e, htab);
 224         case EXPR_OR:
 225                 return manmerge_or(e->child, htab);
 226         case EXPR_AND:
 227                 return manmerge_and(e->child, htab);
 228         default:
 229                 abort();
 230         }
 231 }
 232
 233 static struct ohash *
 234 manmerge_term(struct expr *e, struct ohash *htab)
 235 {
 236         struct dbm_res   res, *rp;
 237         uint64_t         ib;
 238         unsigned int     slot;
 239         int              im;
 240
 241         if (htab == NULL) {
 242                 htab = mandoc_malloc(sizeof(*htab));
 243                 mandoc_ohash_init(htab, 4, offsetof(struct dbm_res, page));
 244         }
 245
 246         for (im = 0, ib = 1; im < KEY_MAX; im++, ib <<= 1) {
 247                 if ((e->bits & ib) == 0)
 248                         continue;
 249
 250                 switch (ib) {
 251                 case TYPE_arch:
 252                         dbm_page_byarch(&e->match);
 253                         break;
 254                 case TYPE_sec:
 255                         dbm_page_bysect(&e->match);
 256                         break;
 257                 case TYPE_Nm:
 258                         dbm_page_byname(&e->match);
 259                         break;
 260                 case TYPE_Nd:
 261                         dbm_page_bydesc(&e->match);
 262                         break;
 263                 default:
 264                         dbm_page_bymacro(im - 2, &e->match);
 265                         break;
 266                 }
 267
 268                 /*
 269                  * When hashing for deduplication, use the unique
 270                  * page ID itself instead of a hash function;
 271                  * that is quite efficient.
 272                  */
 273
 274                 for (;;) {
 275                         res = dbm_page_next();
 276                         if (res.page == -1)
 277                                 break;
 278                         slot = ohash_lookup_memory(htab,
 279                             (char *)&res, sizeof(res.page), res.page);
 280                         if ((rp = ohash_find(htab, slot)) != NULL) {
 281                                 rp->bits |= res.bits;
 282                                 continue;
 283                         }
 284                         rp = mandoc_malloc(sizeof(*rp));
 285                         *rp = res;
 286                         ohash_insert(htab, slot, rp);
 287                 }
 288         }
 289         return htab;
 290 }
 291
 292 static struct ohash *
 293 manmerge_or(struct expr *e, struct ohash *htab)
 294 {
 295         while (e != NULL) {
 296                 htab = manmerge(e, htab);
 297                 e = e->next;
 298         }
 299         return htab;
 300 }
 301
 302 static struct ohash *
 303 manmerge_and(struct expr *e, struct ohash *htab)
 304 {
 305         struct ohash    *hand, *h1, *h2;
 306         struct dbm_res  *res;
 307         unsigned int     slot1, slot2;
 308
 309         /* Evaluate the first term of the AND clause. */
 310
 311         hand = manmerge(e, NULL);
 312
 313         while ((e = e->next) != NULL) {
 314
 315                 /* Evaluate the next term and prepare for ANDing. */
 316
 317                 h2 = manmerge(e, NULL);
 318                 if (ohash_entries(h2) < ohash_entries(hand)) {
 319                         h1 = h2;
 320                         h2 = hand;
 321                 } else
 322                         h1 = hand;
 323                 hand = mandoc_malloc(sizeof(*hand));
 324                 mandoc_ohash_init(hand, 4, offsetof(struct dbm_res, page));
 325
 326                 /* Keep all pages that are in both result sets. */
 327
 328                 for (res = ohash_first(h1, &slot1); res != NULL;
 329                     res = ohash_next(h1, &slot1)) {
 330                         if (ohash_find(h2, ohash_lookup_memory(h2,
 331                             (char *)res, sizeof(res->page),
 332                             res->page)) == NULL)
 333                                 free(res);
 334                         else
 335                                 ohash_insert(hand, ohash_lookup_memory(hand,
 336                                     (char *)res, sizeof(res->page),
 337                                     res->page), res);
 338                 }
 339
 340                 /* Discard the merged results. */
 341
 342                 for (res = ohash_first(h2, &slot2); res != NULL;
 343                     res = ohash_next(h2, &slot2))
 344                         free(res);
 345                 ohash_delete(h2);
 346                 free(h2);
 347                 ohash_delete(h1);
 348                 free(h1);
 349         }
 350
 351         /* Merge the result of the AND into htab. */
 352
 353         if (htab == NULL)
 354                 return hand;
 355
 356         for (res = ohash_first(hand, &slot1); res != NULL;
 357             res = ohash_next(hand, &slot1)) {
 358                 slot2 = ohash_lookup_memory(htab,
 359                     (char *)res, sizeof(res->page), res->page);
 360                 if (ohash_find(htab, slot2) == NULL)
 361                         ohash_insert(htab, slot2, res);
 362                 else
 363                         free(res);
 364         }
 365
 366         /* Discard the merged result. */
 367
 368         ohash_delete(hand);
 369         free(hand);
 370         return htab;
 371 }
 372
 373 void
 374 mansearch_free(struct manpage *res, size_t sz)
 375 {
 376         size_t   i;
 377
 378         for (i = 0; i < sz; i++) {
 379                 free(res[i].file);
 380                 free(res[i].names);
 381                 free(res[i].output);
 382         }
 383         free(res);
 384 }
 385
 386 static int
 387 manpage_compare(const void *vp1, const void *vp2)
 388 {
 389         const struct manpage    *mp1, *mp2;
 390         int                      diff;
 391
 392         mp1 = vp1;
 393         mp2 = vp2;
 394         return (diff = mp2->bits - mp1->bits) ? diff :
 395             (diff = mp1->sec - mp2->sec) ? diff :
 396             strcasecmp(mp1->names, mp2->names);
 397 }
 398
 399 static char *
 400 buildnames(const struct dbm_page *page)
 401 {
 402         char    *buf;
 403         size_t   i, sz;
 404
 405         sz = lstlen(page->name) + 1 + lstlen(page->sect) +
 406             (page->arch == NULL ? 0 : 1 + lstlen(page->arch)) + 2;
 407         buf = mandoc_malloc(sz);
 408         i = 0;
 409         lstcat(buf, &i, page->name);
 410         buf[i++] = '(';
 411         lstcat(buf, &i, page->sect);
 412         if (page->arch != NULL) {
 413                 buf[i++] = '/';
 414                 lstcat(buf, &i, page->arch);
 415         }
 416         buf[i++] = ')';
 417         buf[i++] = '\0';
 418         assert(i == sz);
 419         return buf;
 420 }
 421
 422 /*
 423  * Count the buffer space needed to print the NUL-terminated
 424  * list of NUL-terminated strings, when printing two separator
 425  * characters between strings.
 426  */
 427 static size_t
 428 lstlen(const char *cp)
 429 {
 430         size_t   sz;
 431
 432         for (sz = 0;; sz++) {
 433                 if (cp[0] == '\0') {
 434                         if (cp[1] == '\0')
 435                                 break;
 436                         sz++;
 437                 } else if (cp[0] < ' ')
 438                         sz--;
 439                 cp++;
 440         }
 441         return sz;
 442 }
 443
 444 /*
 445  * Print the NUL-terminated list of NUL-terminated strings
 446  * into the buffer, seperating strings with a comma and a blank.
 447  */
 448 static void
 449 lstcat(char *buf, size_t *i, const char *cp)
 450 {
 451         for (;;) {
 452                 if (cp[0] == '\0') {
 453                         if (cp[1] == '\0')
 454                                 break;
 455                         buf[(*i)++] = ',';
 456                         buf[(*i)++] = ' ';
 457                 } else if (cp[0] >= ' ')
 458                         buf[(*i)++] = cp[0];
 459                 cp++;
 460         }
 461 }
 462
 463 /*
 464  * Return 1 if the string *want occurs in any of the strings
 465  * in the NUL-terminated string list *have, or 0 otherwise.
 466  * If either argument is NULL or empty, assume no filtering
 467  * is desired and return 1.
 468  */
 469 static int
 470 lstmatch(const char *want, const char *have)
 471 {
 472         if (want == NULL || have == NULL || *have == '\0')
 473                 return 1;
 474         while (*have != '\0') {
 475                 if (strcasestr(have, want) != NULL)
 476                         return 1;
 477                 have = strchr(have, '\0') + 1;
 478         }
 479         return 0;
 480 }
 481
 482 /*
 483  * Build a list of values taken by the macro im
 484  * in the manual page with big-endian address addr.
 485  */
 486 static char *
 487 buildoutput(size_t im, int32_t addr)
 488 {
 489         const char      *oldoutput, *sep;
 490         char            *output, *newoutput, *value;
 491
 492         output = NULL;
 493         dbm_macro_bypage(im - 2, addr);
 494         while ((value = dbm_macro_next()) != NULL) {
 495                 if (output == NULL) {
 496                         oldoutput = "";
 497                         sep = "";
 498                 } else {
 499                         oldoutput = output;
 500                         sep = " # ";
 501                 }
 502                 mandoc_asprintf(&newoutput, "%s%s%s", oldoutput, sep, value);
 503                 free(output);
 504                 output = newoutput;
 505         }
 506         return output;
 507 }
 508
 509 /*
 510  * Compile a set of string tokens into an expression.
 511  * Tokens in "argv" are assumed to be individual expression atoms (e.g.,
 512  * "(", "foo=bar", etc.).
 513  */
 514 static struct expr *
 515 exprcomp(const struct mansearch *search, int argc, char *argv[], int *argi)
 516 {
 517         struct expr     *parent, *child;
 518         int              needterm, nested;
 519
 520         if ((nested = *argi) == argc)
 521                 return NULL;
 522         needterm = 1;
 523         parent = child = NULL;
 524         while (*argi < argc) {
 525                 if (strcmp(")", argv[*argi]) == 0) {
 526                         if (needterm)
 527                                 warnx("missing term "
 528                                     "before closing parenthesis");
 529                         needterm = 0;
 530                         if (nested)
 531                                 break;
 532                         warnx("ignoring unmatched right parenthesis");
 533                         ++*argi;
 534                         continue;
 535                 }
 536                 if (strcmp("-o", argv[*argi]) == 0) {
 537                         if (needterm) {
 538                                 if (*argi > 0)
 539                                         warnx("ignoring -o after %s",
 540                                             argv[*argi - 1]);
 541                                 else
 542                                         warnx("ignoring initial -o");
 543                         }
 544                         needterm = 1;
 545                         ++*argi;
 546                         continue;
 547                 }
 548                 needterm = 0;
 549                 if (child == NULL) {
 550                         child = expr_and(search, argc, argv, argi);
 551                         continue;
 552                 }
 553                 if (parent == NULL) {
 554                         parent = mandoc_calloc(1, sizeof(*parent));
 555                         parent->type = EXPR_OR;
 556                         parent->next = NULL;
 557                         parent->child = child;
 558                 }
 559                 child->next = expr_and(search, argc, argv, argi);
 560                 child = child->next;
 561         }
 562         if (needterm && *argi)
 563                 warnx("ignoring trailing %s", argv[*argi - 1]);
 564         return parent == NULL ? child : parent;
 565 }
 566
 567 static struct expr *
 568 expr_and(const struct mansearch *search, int argc, char *argv[], int *argi)
 569 {
 570         struct expr     *parent, *child;
 571         int              needterm;
 572
 573         needterm = 1;
 574         parent = child = NULL;
 575         while (*argi < argc) {
 576                 if (strcmp(")", argv[*argi]) == 0) {
 577                         if (needterm)
 578                                 warnx("missing term "
 579                                     "before closing parenthesis");
 580                         needterm = 0;
 581                         break;
 582                 }
 583                 if (strcmp("-o", argv[*argi]) == 0)
 584                         break;
 585                 if (strcmp("-a", argv[*argi]) == 0) {
 586                         if (needterm) {
 587                                 if (*argi > 0)
 588                                         warnx("ignoring -a after %s",
 589                                             argv[*argi - 1]);
 590                                 else
 591                                         warnx("ignoring initial -a");
 592                         }
 593                         needterm = 1;
 594                         ++*argi;
 595                         continue;
 596                 }
 597                 if (needterm == 0)
 598                         break;
 599                 if (child == NULL) {
 600                         child = exprterm(search, argc, argv, argi);
 601                         if (child != NULL)
 602                                 needterm = 0;
 603                         continue;
 604                 }
 605                 needterm = 0;
 606                 if (parent == NULL) {
 607                         parent = mandoc_calloc(1, sizeof(*parent));
 608                         parent->type = EXPR_AND;
 609                         parent->next = NULL;
 610                         parent->child = child;
 611                 }
 612                 child->next = exprterm(search, argc, argv, argi);
 613                 if (child->next != NULL) {
 614                         child = child->next;
 615                         needterm = 0;
 616                 }
 617         }
 618         if (needterm && *argi)
 619                 warnx("ignoring trailing %s", argv[*argi - 1]);
 620         return parent == NULL ? child : parent;
 621 }
 622
 623 static struct expr *
 624 exprterm(const struct mansearch *search, int argc, char *argv[], int *argi)
 625 {
 626         char             errbuf[BUFSIZ];
 627         struct expr     *e;
 628         char            *key, *val;
 629         uint64_t         iterbit;
 630         int              cs, i, irc;
 631
 632         if (strcmp("(", argv[*argi]) == 0) {
 633                 ++*argi;
 634                 e = exprcomp(search, argc, argv, argi);
 635                 if (*argi < argc) {
 636                         assert(strcmp(")", argv[*argi]) == 0);
 637                         ++*argi;
 638                 } else
 639                         warnx("unclosed parenthesis");
 640                 return e;
 641         }
 642
 643         e = mandoc_calloc(1, sizeof(*e));
 644         e->type = EXPR_TERM;
 645         e->bits = 0;
 646         e->next = NULL;
 647         e->child = NULL;
 648
 649         if (search->argmode == ARG_NAME) {
 650                 e->bits = TYPE_Nm;
 651                 e->match.type = DBM_EXACT;
 652                 e->match.str = argv[(*argi)++];
 653                 return e;
 654         }
 655
 656         /*
 657          * Separate macro keys from search string.
 658          * If needed, request regular expression handling.
 659          */
 660
 661         if (search->argmode == ARG_WORD) {
 662                 e->bits = TYPE_Nm;
 663                 e->match.type = DBM_REGEX;
 664 #if HAVE_REWB_BSD
 665                 mandoc_asprintf(&val, "[[:<:]]%s[[:>:]]", argv[*argi]);
 666 #elif HAVE_REWB_SYSV
 667                 mandoc_asprintf(&val, "\\<%s\\>", argv[*argi]);
 668 #else
 669                 mandoc_asprintf(&val,
 670                     "(^|[^a-zA-Z01-9_])%s([^a-zA-Z01-9_]|$)", argv[*argi]);
 671 #endif
 672                 cs = 0;
 673         } else if ((val = strpbrk(argv[*argi], "=~")) == NULL) {
 674                 e->bits = TYPE_Nm | TYPE_Nd;
 675                 e->match.type = DBM_SUB;
 676                 e->match.str = argv[*argi];
 677         } else {
 678                 if (val == argv[*argi])
 679                         e->bits = TYPE_Nm | TYPE_Nd;
 680                 if (*val == '=') {
 681                         e->match.type = DBM_SUB;
 682                         e->match.str = val + 1;
 683                 } else
 684                         e->match.type = DBM_REGEX;
 685                 *val++ = '\0';
 686                 if (strstr(argv[*argi], "arch") != NULL)
 687                         cs = 0;
 688         }
 689
 690         /* Compile regular expressions. */
 691
 692         if (e->match.type == DBM_REGEX) {
 693                 e->match.re = mandoc_malloc(sizeof(*e->match.re));
 694                 irc = regcomp(e->match.re, val,
 695                     REG_EXTENDED | REG_NOSUB | (cs ? 0 : REG_ICASE));
 696                 if (irc) {
 697                         regerror(irc, e->match.re, errbuf, sizeof(errbuf));
 698                         warnx("regcomp /%s/: %s", val, errbuf);
 699                 }
 700                 if (search->argmode == ARG_WORD)
 701                         free(val);
 702                 if (irc) {
 703                         free(e->match.re);
 704                         free(e);
 705                         ++*argi;
 706                         return NULL;
 707                 }
 708         }
 709
 710         if (e->bits) {
 711                 ++*argi;
 712                 return e;
 713         }
 714
 715         /*
 716          * Parse out all possible fields.
 717          * If the field doesn't resolve, bail.
 718          */
 719
 720         while (NULL != (key = strsep(&argv[*argi], ","))) {
 721                 if ('\0' == *key)
 722                         continue;
 723                 for (i = 0, iterbit = 1; i < KEY_MAX; i++, iterbit <<= 1) {
 724                         if (0 == strcasecmp(key, mansearch_keynames[i])) {
 725                                 e->bits |= iterbit;
 726                                 break;
 727                         }
 728                 }
 729                 if (i == KEY_MAX) {
 730                         if (strcasecmp(key, "any"))
 731                                 warnx("treating unknown key "
 732                                     "\"%s\" as \"any\"", key);
 733                         e->bits |= ~0ULL;
 734                 }
 735         }
 736
 737         ++*argi;
 738         return e;
 739 }
 740
 741 static void
 742 exprfree(struct expr *e)
 743 {
 744         if (e->next != NULL)
 745                 exprfree(e->next);
 746         if (e->child != NULL)
 747                 exprfree(e->child);
 748         free(e);
 749 }