usr.sbin/makefs/walk.c

   1 /*      $NetBSD: walk.c,v 1.23 2006/10/10 01:55:45 dbj Exp $    */
   2
   3 /*
   4  * Copyright (c) 2001 Wasabi Systems, Inc.
   5  * All rights reserved.
   6  *
   7  * Written by Luke Mewburn for Wasabi Systems, Inc.
   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. All advertising materials mentioning features or use of this software
  18  *    must display the following acknowledgement:
  19  *      This product includes software developed for the NetBSD Project by
  20  *      Wasabi Systems, Inc.
  21  * 4. The name of Wasabi Systems, Inc. may not be used to endorse
  22  *    or promote products derived from this software without specific prior
  23  *    written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
  26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  27  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  28  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
  29  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  30  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  31  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  32  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  33  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  35  * POSSIBILITY OF SUCH DAMAGE.
  36  */
  37
  38 #if HAVE_NBTOOL_CONFIG_H
  39 #include "nbtool_config.h"
  40 #endif
  41
  42 #include <sys/cdefs.h>
  43 #if defined(__RCSID) && !defined(__lint)
  44 __RCSID("$NetBSD: walk.c,v 1.23 2006/10/10 01:55:45 dbj Exp $");
  45 #endif  /* !__lint */
  46
  47 #include <sys/param.h>
  48
  49 #include <assert.h>
  50 #include <errno.h>
  51 #include <fcntl.h>
  52 #include <stdio.h>
  53 #include <dirent.h>
  54 #include <stdlib.h>
  55 #include <string.h>
  56 #include <unistd.h>
  57 #include <sys/stat.h>
  58
  59 #include "makefs.h"
  60 #include "mtree.h"
  61
  62 static  void     apply_specdir(const char *, NODE *, fsnode *, int);
  63 static  void     apply_specentry(const char *, NODE *, fsnode *);
  64 static  fsnode  *create_fsnode(const char *, struct stat *);
  65 static  fsinode *link_check(fsinode *);
  66
  67
  68 /*
  69  * walk_dir --
  70  *      build a tree of fsnodes from `dir', with a parent fsnode of `parent'
  71  *      (which may be NULL for the root of the tree).
  72  *      each "level" is a directory, with the "." entry guaranteed to be
  73  *      at the start of the list, and without ".." entries.
  74  */
  75 fsnode *
  76 walk_dir(const char *dir, fsnode *parent)
  77 {
  78         fsnode          *first, *cur, *prev;
  79         DIR             *dirp;
  80         struct dirent   *dent;
  81         char            path[MAXPATHLEN + 1];
  82         struct stat     stbuf;
  83
  84         assert(dir != NULL);
  85
  86         if (debug & DEBUG_WALK_DIR)
  87                 printf("walk_dir: %s %p\n", dir, parent);
  88         if ((dirp = opendir(dir)) == NULL)
  89                 err(1, "Can't opendir `%s'", dir);
  90         first = prev = NULL;
  91         while ((dent = readdir(dirp)) != NULL) {
  92                 if (strcmp(dent->d_name, "..") == 0)
  93                         continue;
  94                 if (debug & DEBUG_WALK_DIR_NODE)
  95                         printf("scanning %s/%s\n", dir, dent->d_name);
  96                 if (snprintf(path, sizeof(path), "%s/%s", dir, dent->d_name)
  97                     >= sizeof(path))
  98                         errx(1, "Pathname too long.");
  99                 if (lstat(path, &stbuf) == -1)
 100                         err(1, "Can't lstat `%s'", path);
 101 #ifdef S_ISSOCK
 102                 if (S_ISSOCK(stbuf.st_mode & S_IFMT)) {
 103                         if (debug & DEBUG_WALK_DIR_NODE)
 104                                 printf("  skipping socket %s\n", path);
 105                         continue;
 106                 }
 107 #endif
 108
 109                 cur = create_fsnode(dent->d_name, &stbuf);
 110                 cur->parent = parent;
 111                 if (strcmp(dent->d_name, ".") == 0) {
 112                                 /* ensure "." is at the start of the list */
 113                         cur->next = first;
 114                         first = cur;
 115                         if (! prev)
 116                                 prev = cur;
 117                 } else {                        /* not "." */
 118                         if (prev)
 119                                 prev->next = cur;
 120                         prev = cur;
 121                         if (!first)
 122                                 first = cur;
 123                         if (S_ISDIR(cur->type)) {
 124                                 cur->child = walk_dir(path, cur);
 125                                 continue;
 126                         }
 127                 }
 128                 if (stbuf.st_nlink > 1) {
 129                         fsinode *curino;
 130
 131                         curino = link_check(cur->inode);
 132                         if (curino != NULL) {
 133                                 free(cur->inode);
 134                                 cur->inode = curino;
 135                                 cur->inode->nlink++;
 136                                 if (debug & DEBUG_WALK_DIR_LINKCHECK)
 137                                         printf("link_check: found [%llu, %llu]\n",
 138                                             (unsigned long long)curino->st.st_dev,
 139                                             (unsigned long long)curino->st.st_ino);
 140                         }
 141                 }
 142                 if (S_ISLNK(cur->type)) {
 143                         char    slink[PATH_MAX+1];
 144                         int     llen;
 145
 146                         llen = readlink(path, slink, sizeof(slink) - 1);
 147                         if (llen == -1)
 148                                 err(1, "Readlink `%s'", path);
 149                         slink[llen] = '\0';
 150                         if ((cur->symlink = strdup(slink)) == NULL)
 151                                 err(1, "Memory allocation error");
 152                 }
 153         }
 154         for (cur = first; cur != NULL; cur = cur->next)
 155                 cur->first = first;
 156         if (closedir(dirp) == -1)
 157                 err(1, "Can't closedir `%s'", dir);
 158         return (first);
 159 }
 160
 161 static fsnode *
 162 create_fsnode(const char *name, struct stat *stbuf)
 163 {
 164         fsnode *cur;
 165
 166         if ((cur = calloc(1, sizeof(fsnode))) == NULL ||
 167             (cur->name = strdup(name)) == NULL ||
 168             (cur->inode = calloc(1, sizeof(fsinode))) == NULL)
 169                 err(1, "Memory allocation error");
 170         cur->type = stbuf->st_mode & S_IFMT;
 171         cur->inode->nlink = 1;
 172         cur->inode->st = *stbuf;
 173         return (cur);
 174 }
 175
 176 /*
 177  * free_fsnodes --
 178  *      Removes node from tree and frees it and all of
 179  *   its decendents.
 180  */
 181 void
 182 free_fsnodes(fsnode *node)
 183 {
 184         fsnode  *cur, *next;
 185
 186         assert(node != NULL);
 187
 188         /* for ".", start with actual parent node */
 189         if (node->first == node) {
 190                 assert(node->name[0] == '.' && node->name[1] == '\0');
 191                 if (node->parent) {
 192                         assert(node->parent->child == node);
 193                         node = node->parent;
 194                 }
 195         }
 196
 197         /* Find ourselves in our sibling list and unlink */
 198         if (node->first != node) {
 199                 for (cur = node->first; cur->next; cur = cur->next) {
 200                         if (cur->next == node) {
 201                                 cur->next = node->next;
 202                                 node->next = NULL;
 203                                 break;
 204                         }
 205                 }
 206         }
 207
 208         for (cur = node; cur != NULL; cur = next) {
 209                 next = cur->next;
 210                 if (cur->child) {
 211                         cur->child->parent = NULL;
 212                         free_fsnodes(cur->child);
 213                 }
 214                 if (cur->inode->nlink-- == 1)
 215                         free(cur->inode);
 216                 if (cur->symlink)
 217                         free(cur->symlink);
 218                 free(cur->name);
 219                 free(cur);
 220         }
 221 }
 222
 223 /*
 224  * apply_specfile --
 225  *      read in the mtree(8) specfile, and apply it to the tree
 226  *      at dir,parent. parameters in parent on equivalent types
 227  *      will be changed to those found in specfile, and missing
 228  *      entries will be added.
 229  */
 230 void
 231 apply_specfile(const char *specfile, const char *dir, fsnode *parent, int speconly)
 232 {
 233         struct timeval   start;
 234         FILE    *fp;
 235         NODE    *root;
 236
 237         assert(specfile != NULL);
 238         assert(parent != NULL);
 239
 240         if (debug & DEBUG_APPLY_SPECFILE)
 241                 printf("apply_specfile: %s, %s %p\n", specfile, dir, parent);
 242
 243                                 /* read in the specfile */
 244         if ((fp = fopen(specfile, "r")) == NULL)
 245                 err(1, "Can't open `%s'", specfile);
 246         TIMER_START(start);
 247         root = spec(fp);
 248         TIMER_RESULTS(start, "spec");
 249         if (fclose(fp) == EOF)
 250                 err(1, "Can't close `%s'", specfile);
 251
 252                                 /* perform some sanity checks */
 253         if (root == NULL)
 254                 errx(1, "Specfile `%s' did not contain a tree", specfile);
 255         assert(strcmp(root->name, ".") == 0);
 256         assert(root->type == F_DIR);
 257
 258                                 /* merge in the changes */
 259         apply_specdir(dir, root, parent, speconly);
 260
 261         free_nodes(root);
 262 }
 263
 264 static void
 265 apply_specdir(const char *dir, NODE *specnode, fsnode *dirnode, int speconly)
 266 {
 267         char     path[MAXPATHLEN + 1];
 268         NODE    *curnode;
 269         fsnode  *curfsnode;
 270
 271         assert(specnode != NULL);
 272         assert(dirnode != NULL);
 273
 274         if (debug & DEBUG_APPLY_SPECFILE)
 275                 printf("apply_specdir: %s %p %p\n", dir, specnode, dirnode);
 276
 277         if (specnode->type != F_DIR)
 278                 errx(1, "Specfile node `%s/%s' is not a directory",
 279                     dir, specnode->name);
 280         if (dirnode->type != S_IFDIR)
 281                 errx(1, "Directory node `%s/%s' is not a directory",
 282                     dir, dirnode->name);
 283
 284         apply_specentry(dir, specnode, dirnode);
 285
 286         /* Remove any filesystem nodes not found in specfile */
 287         /* XXX inefficient.  This is O^2 in each dir and it would
 288          * have been better never to have walked this part of the tree
 289          * to begin with
 290          */
 291         if (speconly) {
 292                 fsnode *next;
 293                 assert(dirnode->name[0] == '.' && dirnode->name[1] == '\0');
 294                 for (curfsnode = dirnode->next; curfsnode != NULL; curfsnode = next) {
 295                         next = curfsnode->next;
 296                         for (curnode = specnode->child; curnode != NULL;
 297                              curnode = curnode->next) {
 298                                 if (strcmp(curnode->name, curfsnode->name) == 0)
 299                                         break;
 300                         }
 301                         if (curnode == NULL) {
 302                                 if (debug & DEBUG_APPLY_SPECONLY) {
 303                                         printf("apply_specdir: trimming %s/%s %p\n", dir, curfsnode->name, curfsnode);
 304                                 }
 305                                 free_fsnodes(curfsnode);
 306                         }
 307                 }
 308         }
 309
 310                         /* now walk specnode->child matching up with dirnode */
 311         for (curnode = specnode->child; curnode != NULL;
 312             curnode = curnode->next) {
 313                 if (debug & DEBUG_APPLY_SPECENTRY)
 314                         printf("apply_specdir:  spec %s\n",
 315                             curnode->name);
 316                 for (curfsnode = dirnode->next; curfsnode != NULL;
 317                     curfsnode = curfsnode->next) {
 318 #if 0   /* too verbose for now */
 319                         if (debug & DEBUG_APPLY_SPECENTRY)
 320                                 printf("apply_specdir:  dirent %s\n",
 321                                     curfsnode->name);
 322 #endif
 323                         if (strcmp(curnode->name, curfsnode->name) == 0)
 324                                 break;
 325                 }
 326                 if (snprintf(path, sizeof(path), "%s/%s",
 327                     dir, curnode->name) >= sizeof(path))
 328                         errx(1, "Pathname too long.");
 329                 if (curfsnode == NULL) {        /* need new entry */
 330                         struct stat     stbuf;
 331
 332                                             /*
 333                                              * don't add optional spec entries
 334                                              * that lack an existing fs entry
 335                                              */
 336                         if ((curnode->flags & F_OPT) &&
 337                             lstat(path, &stbuf) == -1)
 338                                         continue;
 339
 340                                         /* check that enough info is provided */
 341 #define NODETEST(t, m)                                                  \
 342                         if (!(t))                                       \
 343                                 errx(1, "`%s': %s not provided", path, m)
 344                         NODETEST(curnode->flags & F_TYPE, "type");
 345                         NODETEST(curnode->flags & F_MODE, "mode");
 346                                 /* XXX: require F_TIME ? */
 347                         NODETEST(curnode->flags & F_GID ||
 348                             curnode->flags & F_GNAME, "group");
 349                         NODETEST(curnode->flags & F_UID ||
 350                             curnode->flags & F_UNAME, "user");
 351                         if (curnode->type == F_BLOCK || curnode->type == F_CHAR)
 352                                 NODETEST(curnode->flags & F_DEV,
 353                                     "device number");
 354 #undef NODETEST
 355
 356                         if (debug & DEBUG_APPLY_SPECFILE)
 357                                 printf("apply_specdir: adding %s\n",
 358                                     curnode->name);
 359                                         /* build minimal fsnode */
 360                         memset(&stbuf, 0, sizeof(stbuf));
 361                         stbuf.st_mode = nodetoino(curnode->type);
 362                         stbuf.st_nlink = 1;
 363                         stbuf.st_mtime = stbuf.st_atime =
 364                             stbuf.st_ctime = start_time.tv_sec;
 365 #if HAVE_STRUCT_STAT_ST_MTIMENSEC
 366                         stbuf.st_mtimensec = stbuf.st_atimensec =
 367                             stbuf.st_ctimensec = start_time.tv_nsec;
 368 #endif
 369                         curfsnode = create_fsnode(curnode->name, &stbuf);
 370                         curfsnode->parent = dirnode->parent;
 371                         curfsnode->first = dirnode;
 372                         curfsnode->next = dirnode->next;
 373                         dirnode->next = curfsnode;
 374                         if (curfsnode->type == S_IFDIR) {
 375                                         /* for dirs, make "." entry as well */
 376                                 curfsnode->child = create_fsnode(".", &stbuf);
 377                                 curfsnode->child->parent = curfsnode;
 378                                 curfsnode->child->first = curfsnode->child;
 379                         }
 380                         if (curfsnode->type == S_IFLNK) {
 381                                 assert(curnode->slink != NULL);
 382                                         /* for symlinks, copy the target */
 383                                 if ((curfsnode->symlink =
 384                                     strdup(curnode->slink)) == NULL)
 385                                         err(1, "Memory allocation error");
 386                         }
 387                 }
 388                 apply_specentry(dir, curnode, curfsnode);
 389                 if (curnode->type == F_DIR) {
 390                         if (curfsnode->type != S_IFDIR)
 391                                 errx(1, "`%s' is not a directory", path);
 392                         assert (curfsnode->child != NULL);
 393                         apply_specdir(path, curnode, curfsnode->child, speconly);
 394                 }
 395         }
 396 }
 397
 398 static void
 399 apply_specentry(const char *dir, NODE *specnode, fsnode *dirnode)
 400 {
 401
 402         assert(specnode != NULL);
 403         assert(dirnode != NULL);
 404
 405         if (nodetoino(specnode->type) != dirnode->type)
 406                 errx(1, "`%s/%s' type mismatch: specfile %s, tree %s",
 407                     dir, specnode->name, inode_type(nodetoino(specnode->type)),
 408                     inode_type(dirnode->type));
 409
 410         if (debug & DEBUG_APPLY_SPECENTRY)
 411                 printf("apply_specentry: %s/%s\n", dir, dirnode->name);
 412
 413 #define ASEPRINT(t, b, o, n) \
 414                 if (debug & DEBUG_APPLY_SPECENTRY) \
 415                         printf("\t\t\tchanging %s from " b " to " b "\n", \
 416                             t, o, n)
 417
 418         if (specnode->flags & (F_GID | F_GNAME)) {
 419                 ASEPRINT("gid", "%d",
 420                     dirnode->inode->st.st_gid, specnode->st_gid);
 421                 dirnode->inode->st.st_gid = specnode->st_gid;
 422         }
 423         if (specnode->flags & F_MODE) {
 424                 ASEPRINT("mode", "%#o",
 425                     dirnode->inode->st.st_mode & ALLPERMS, specnode->st_mode);
 426                 dirnode->inode->st.st_mode &= ~ALLPERMS;
 427                 dirnode->inode->st.st_mode |= (specnode->st_mode & ALLPERMS);
 428         }
 429                 /* XXX: ignoring F_NLINK for now */
 430         if (specnode->flags & F_SIZE) {
 431                 ASEPRINT("size", "%lld",
 432                     (long long)dirnode->inode->st.st_size,
 433                     (long long)specnode->st_size);
 434                 dirnode->inode->st.st_size = specnode->st_size;
 435         }
 436         if (specnode->flags & F_SLINK) {
 437                 assert(dirnode->symlink != NULL);
 438                 assert(specnode->slink != NULL);
 439                 ASEPRINT("symlink", "%s", dirnode->symlink, specnode->slink);
 440                 free(dirnode->symlink);
 441                 if ((dirnode->symlink = strdup(specnode->slink)) == NULL)
 442                         err(1, "Memory allocation error");
 443         }
 444         if (specnode->flags & F_TIME) {
 445                 ASEPRINT("time", "%ld",
 446                     (long)dirnode->inode->st.st_mtime,
 447                     (long)specnode->st_mtimespec.tv_sec);
 448                 dirnode->inode->st.st_mtime =           specnode->st_mtimespec.tv_sec;
 449                 dirnode->inode->st.st_atime =           specnode->st_mtimespec.tv_sec;
 450                 dirnode->inode->st.st_ctime =           start_time.tv_sec;
 451 #if HAVE_STRUCT_STAT_ST_MTIMENSEC
 452                 dirnode->inode->st.st_mtimensec =       specnode->st_mtimespec.tv_nsec;
 453                 dirnode->inode->st.st_atimensec =       specnode->st_mtimespec.tv_nsec;
 454                 dirnode->inode->st.st_ctimensec =       start_time.tv_nsec;
 455 #endif
 456         }
 457         if (specnode->flags & (F_UID | F_UNAME)) {
 458                 ASEPRINT("uid", "%d",
 459                     dirnode->inode->st.st_uid, specnode->st_uid);
 460                 dirnode->inode->st.st_uid = specnode->st_uid;
 461         }
 462 #if HAVE_STRUCT_STAT_ST_FLAGS
 463         if (specnode->flags & F_FLAGS) {
 464                 ASEPRINT("flags", "%#lX",
 465                     (unsigned long)dirnode->inode->st.st_flags,
 466                     (unsigned long)specnode->st_flags);
 467                 dirnode->inode->st.st_flags = specnode->st_flags;
 468         }
 469 #endif
 470         if (specnode->flags & F_DEV) {
 471                 ASEPRINT("rdev", "%#llx",
 472                     (unsigned long long)dirnode->inode->st.st_rdev,
 473                     (unsigned long long)specnode->st_rdev);
 474                 dirnode->inode->st.st_rdev = specnode->st_rdev;
 475         }
 476 #undef ASEPRINT
 477
 478         dirnode->flags |= FSNODE_F_HASSPEC;
 479 }
 480
 481
 482 /*
 483  * dump_fsnodes --
 484  *      dump the fsnodes from `cur', based in the directory `dir'
 485  */
 486 void
 487 dump_fsnodes(const char *dir, fsnode *root)
 488 {
 489         fsnode  *cur;
 490         char    path[MAXPATHLEN + 1];
 491
 492         assert (dir != NULL);
 493         printf("dump_fsnodes: %s %p\n", dir, root);
 494         for (cur = root; cur != NULL; cur = cur->next) {
 495                 if (snprintf(path, sizeof(path), "%s/%s", dir, cur->name)
 496                     >= sizeof(path))
 497                         errx(1, "Pathname too long.");
 498
 499                 if (debug & DEBUG_DUMP_FSNODES_VERBOSE)
 500                         printf("cur=%8p parent=%8p first=%8p ",
 501                             cur, cur->parent, cur->first);
 502                 printf("%7s: %s", inode_type(cur->type), path);
 503                 if (S_ISLNK(cur->type)) {
 504                         assert(cur->symlink != NULL);
 505                         printf(" -> %s", cur->symlink);
 506                 } else {
 507                         assert (cur->symlink == NULL);
 508                 }
 509                 if (cur->inode->nlink > 1)
 510                         printf(", nlinks=%d", cur->inode->nlink);
 511                 putchar('\n');
 512
 513                 if (cur->child) {
 514                         assert (cur->type == S_IFDIR);
 515                         dump_fsnodes(path, cur->child);
 516                 }
 517         }
 518         printf("dump_fsnodes: finished %s\n", dir);
 519 }
 520
 521
 522 /*
 523  * inode_type --
 524  *      for a given inode type `mode', return a descriptive string.
 525  *      for most cases, uses inotype() from mtree/misc.c
 526  */
 527 const char *
 528 inode_type(mode_t mode)
 529 {
 530
 531         if (S_ISLNK(mode))
 532                 return ("symlink");     /* inotype() returns "link"...  */
 533         return (inotype(mode));
 534 }
 535
 536
 537 /*
 538  * link_check --
 539  *      return pointer to fsinode matching `entry's st_ino & st_dev if it exists,
 540  *      otherwise add `entry' to table and return NULL
 541  */
 542 /* This was borrowed from du.c and tweaked to keep an fsnode
 543  * pointer instead. -- dbj@netbsd.org
 544  */
 545 static fsinode *
 546 link_check(fsinode *entry)
 547 {
 548         static struct entry {
 549                 fsinode *data;
 550         } *htable;
 551         static int htshift;  /* log(allocated size) */
 552         static int htmask;   /* allocated size - 1 */
 553         static int htused;   /* 2*number of insertions */
 554         int h, h2;
 555         uint64_t tmp;
 556         /* this constant is (1<<64)/((1+sqrt(5))/2)
 557          * aka (word size)/(golden ratio)
 558          */
 559         const uint64_t HTCONST = 11400714819323198485ULL;
 560         const int HTBITS = 64;
 561
 562         /* Never store zero in hashtable */
 563         assert(entry);
 564
 565         /* Extend hash table if necessary, keep load under 0.5 */
 566         if (htused<<1 >= htmask) {
 567                 struct entry *ohtable;
 568
 569                 if (!htable)
 570                         htshift = 10;   /* starting hashtable size */
 571                 else
 572                         htshift++;   /* exponential hashtable growth */
 573
 574                 htmask  = (1 << htshift) - 1;
 575                 htused = 0;
 576
 577                 ohtable = htable;
 578                 htable = calloc(htmask+1, sizeof(*htable));
 579                 if (!htable)
 580                         err(1, "Memory allocation error");
 581
 582                 /* populate newly allocated hashtable */
 583                 if (ohtable) {
 584                         int i;
 585                         for (i = 0; i <= htmask>>1; i++)
 586                                 if (ohtable[i].data)
 587                                         link_check(ohtable[i].data);
 588                         free(ohtable);
 589                 }
 590         }
 591
 592         /* multiplicative hashing */
 593         tmp = entry->st.st_dev;
 594         tmp <<= HTBITS>>1;
 595         tmp |=  entry->st.st_ino;
 596         tmp *= HTCONST;
 597         h  = tmp >> (HTBITS - htshift);
 598         h2 = 1 | ( tmp >> (HTBITS - (htshift<<1) - 1)); /* must be odd */
 599
 600         /* open address hashtable search with double hash probing */
 601         while (htable[h].data) {
 602                 if ((htable[h].data->st.st_ino == entry->st.st_ino) &&
 603                     (htable[h].data->st.st_dev == entry->st.st_dev)) {
 604                         return htable[h].data;
 605                 }
 606                 h = (h + h2) & htmask;
 607         }
 608
 609         /* Insert the current entry into hashtable */
 610         htable[h].data = entry;
 611         htused++;
 612         return NULL;
 613 }