usr.sbin/makefs/walk.c

   1 /*      $NetBSD: walk.c,v 1.24 2008/12/28 21:51:46 christos 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
  39 #include <sys/cdefs.h>
  40 __FBSDID("$FreeBSD$");
  41
  42 #include <sys/param.h>
  43
  44 #include <assert.h>
  45 #include <errno.h>
  46 #include <fcntl.h>
  47 #include <stdio.h>
  48 #include <dirent.h>
  49 #include <stdlib.h>
  50 #include <string.h>
  51 #include <unistd.h>
  52 #include <sys/stat.h>
  53
  54 #include "makefs.h"
  55 #include "mtree.h"
  56 #include "extern.h"
  57
  58 static  void     apply_specdir(const char *, NODE *, fsnode *, int);
  59 static  void     apply_specentry(const char *, NODE *, fsnode *);
  60 static  fsnode  *create_fsnode(const char *, struct stat *);
  61 static  fsinode *link_check(fsinode *);
  62
  63
  64 /*
  65  * walk_dir --
  66  *      build a tree of fsnodes from `dir', with a parent fsnode of `parent'
  67  *      (which may be NULL for the root of the tree).
  68  *      each "level" is a directory, with the "." entry guaranteed to be
  69  *      at the start of the list, and without ".." entries.
  70  */
  71 fsnode *
  72 walk_dir(const char *dir, fsnode *parent)
  73 {
  74         fsnode          *first, *cur, *prev;
  75         DIR             *dirp;
  76         struct dirent   *dent;
  77         char            path[MAXPATHLEN + 1];
  78         struct stat     stbuf;
  79
  80         assert(dir != NULL);
  81
  82         if (debug & DEBUG_WALK_DIR)
  83                 printf("walk_dir: %s %p\n", dir, parent);
  84         if ((dirp = opendir(dir)) == NULL)
  85                 err(1, "Can't opendir `%s'", dir);
  86         first = prev = NULL;
  87         while ((dent = readdir(dirp)) != NULL) {
  88                 if (strcmp(dent->d_name, "..") == 0)
  89                         continue;
  90                 if (debug & DEBUG_WALK_DIR_NODE)
  91                         printf("scanning %s/%s\n", dir, dent->d_name);
  92                 if (snprintf(path, sizeof(path), "%s/%s", dir, dent->d_name)
  93                     >= sizeof(path))
  94                         errx(1, "Pathname too long.");
  95                 if (lstat(path, &stbuf) == -1)
  96                         err(1, "Can't lstat `%s'", path);
  97 #ifdef S_ISSOCK
  98                 if (S_ISSOCK(stbuf.st_mode & S_IFMT)) {
  99                         if (debug & DEBUG_WALK_DIR_NODE)
 100                                 printf("  skipping socket %s\n", path);
 101                         continue;
 102                 }
 103 #endif
 104
 105                 cur = create_fsnode(dent->d_name, &stbuf);
 106                 cur->parent = parent;
 107                 if (strcmp(dent->d_name, ".") == 0) {
 108                                 /* ensure "." is at the start of the list */
 109                         cur->next = first;
 110                         first = cur;
 111                         if (! prev)
 112                                 prev = cur;
 113                 } else {                        /* not "." */
 114                         if (prev)
 115                                 prev->next = cur;
 116                         prev = cur;
 117                         if (!first)
 118                                 first = cur;
 119                         if (S_ISDIR(cur->type)) {
 120                                 cur->child = walk_dir(path, cur);
 121                                 continue;
 122                         }
 123                 }
 124                 if (stbuf.st_nlink > 1) {
 125                         fsinode *curino;
 126
 127                         curino = link_check(cur->inode);
 128                         if (curino != NULL) {
 129                                 free(cur->inode);
 130                                 cur->inode = curino;
 131                                 cur->inode->nlink++;
 132                                 if (debug & DEBUG_WALK_DIR_LINKCHECK)
 133                                         printf("link_check: found [%llu, %llu]\n",
 134                                             (unsigned long long)curino->st.st_dev,
 135                                             (unsigned long long)curino->st.st_ino);
 136                         }
 137                 }
 138                 if (S_ISLNK(cur->type)) {
 139                         char    slink[PATH_MAX+1];
 140                         int     llen;
 141
 142                         llen = readlink(path, slink, sizeof(slink) - 1);
 143                         if (llen == -1)
 144                                 err(1, "Readlink `%s'", path);
 145                         slink[llen] = '\0';
 146                         if ((cur->symlink = strdup(slink)) == NULL)
 147                                 err(1, "Memory allocation error");
 148                 }
 149         }
 150         for (cur = first; cur != NULL; cur = cur->next)
 151                 cur->first = first;
 152         if (closedir(dirp) == -1)
 153                 err(1, "Can't closedir `%s'", dir);
 154         return (first);
 155 }
 156
 157 static fsnode *
 158 create_fsnode(const char *name, struct stat *stbuf)
 159 {
 160         fsnode *cur;
 161
 162         if ((cur = calloc(1, sizeof(fsnode))) == NULL ||
 163             (cur->name = strdup(name)) == NULL ||
 164             (cur->inode = calloc(1, sizeof(fsinode))) == NULL)
 165                 err(1, "Memory allocation error");
 166         cur->type = stbuf->st_mode & S_IFMT;
 167         cur->inode->nlink = 1;
 168         cur->inode->st = *stbuf;
 169         return (cur);
 170 }
 171
 172 /*
 173  * free_fsnodes --
 174  *      Removes node from tree and frees it and all of
 175  *   its decendents.
 176  */
 177 void
 178 free_fsnodes(fsnode *node)
 179 {
 180         fsnode  *cur, *next;
 181
 182         assert(node != NULL);
 183
 184         /* for ".", start with actual parent node */
 185         if (node->first == node) {
 186                 assert(node->name[0] == '.' && node->name[1] == '\0');
 187                 if (node->parent) {
 188                         assert(node->parent->child == node);
 189                         node = node->parent;
 190                 }
 191         }
 192
 193         /* Find ourselves in our sibling list and unlink */
 194         if (node->first != node) {
 195                 for (cur = node->first; cur->next; cur = cur->next) {
 196                         if (cur->next == node) {
 197                                 cur->next = node->next;
 198                                 node->next = NULL;
 199                                 break;
 200                         }
 201                 }
 202         }
 203
 204         for (cur = node; cur != NULL; cur = next) {
 205                 next = cur->next;
 206                 if (cur->child) {
 207                         cur->child->parent = NULL;
 208                         free_fsnodes(cur->child);
 209                 }
 210                 if (cur->inode->nlink-- == 1)
 211                         free(cur->inode);
 212                 if (cur->symlink)
 213                         free(cur->symlink);
 214                 free(cur->name);
 215                 free(cur);
 216         }
 217 }
 218
 219 /*
 220  * apply_specfile --
 221  *      read in the mtree(8) specfile, and apply it to the tree
 222  *      at dir,parent. parameters in parent on equivalent types
 223  *      will be changed to those found in specfile, and missing
 224  *      entries will be added.
 225  */
 226 void
 227 apply_specfile(const char *specfile, const char *dir, fsnode *parent, int speconly)
 228 {
 229         struct timeval   start;
 230         FILE    *fp;
 231         NODE    *root;
 232
 233         assert(specfile != NULL);
 234         assert(parent != NULL);
 235
 236         if (debug & DEBUG_APPLY_SPECFILE)
 237                 printf("apply_specfile: %s, %s %p\n", specfile, dir, parent);
 238
 239                                 /* read in the specfile */
 240         if ((fp = fopen(specfile, "r")) == NULL)
 241                 err(1, "Can't open `%s'", specfile);
 242         TIMER_START(start);
 243         root = mtree_readspec(fp);
 244         TIMER_RESULTS(start, "spec");
 245         if (fclose(fp) == EOF)
 246                 err(1, "Can't close `%s'", specfile);
 247
 248                                 /* perform some sanity checks */
 249         if (root == NULL)
 250                 errx(1, "Specfile `%s' did not contain a tree", specfile);
 251         assert(strcmp(root->name, ".") == 0);
 252         assert(root->type == F_DIR);
 253
 254                                 /* merge in the changes */
 255         apply_specdir(dir, root, parent, speconly);
 256
 257 }
 258
 259 static u_int
 260 nodetoino(u_int type)
 261 {
 262
 263         switch (type) {
 264         case F_BLOCK:
 265                 return S_IFBLK;
 266         case F_CHAR:
 267                 return S_IFCHR;
 268         case F_DIR:
 269                 return S_IFDIR;
 270         case F_FIFO:
 271                 return S_IFIFO;
 272         case F_FILE:
 273                 return S_IFREG;
 274         case F_LINK:
 275                 return S_IFLNK;
 276         case F_SOCK:
 277                 return S_IFSOCK;
 278         default:
 279                 printf("unknown type %d", type);
 280                 abort();
 281         }
 282         /* NOTREACHED */
 283 }
 284
 285
 286 static void
 287 apply_specdir(const char *dir, NODE *specnode, fsnode *dirnode, int speconly)
 288 {
 289         char     path[MAXPATHLEN + 1];
 290         NODE    *curnode;
 291         fsnode  *curfsnode;
 292
 293         assert(specnode != NULL);
 294         assert(dirnode != NULL);
 295
 296         if (debug & DEBUG_APPLY_SPECFILE)
 297                 printf("apply_specdir: %s %p %p\n", dir, specnode, dirnode);
 298
 299         if (specnode->type != F_DIR)
 300                 errx(1, "Specfile node `%s/%s' is not a directory",
 301                     dir, specnode->name);
 302         if (dirnode->type != S_IFDIR)
 303                 errx(1, "Directory node `%s/%s' is not a directory",
 304                     dir, dirnode->name);
 305
 306         apply_specentry(dir, specnode, dirnode);
 307
 308         /* Remove any filesystem nodes not found in specfile */
 309         /* XXX inefficient.  This is O^2 in each dir and it would
 310          * have been better never to have walked this part of the tree
 311          * to begin with
 312          */
 313         if (speconly) {
 314                 fsnode *next;
 315                 assert(dirnode->name[0] == '.' && dirnode->name[1] == '\0');
 316                 for (curfsnode = dirnode->next; curfsnode != NULL; curfsnode = next) {
 317                         next = curfsnode->next;
 318                         for (curnode = specnode->child; curnode != NULL;
 319                              curnode = curnode->next) {
 320                                 if (strcmp(curnode->name, curfsnode->name) == 0)
 321                                         break;
 322                         }
 323                         if (curnode == NULL) {
 324                                 if (debug & DEBUG_APPLY_SPECONLY) {
 325                                         printf("apply_specdir: trimming %s/%s %p\n", dir, curfsnode->name, curfsnode);
 326                                 }
 327                                 free_fsnodes(curfsnode);
 328                         }
 329                 }
 330         }
 331
 332                         /* now walk specnode->child matching up with dirnode */
 333         for (curnode = specnode->child; curnode != NULL;
 334             curnode = curnode->next) {
 335                 if (debug & DEBUG_APPLY_SPECENTRY)
 336                         printf("apply_specdir:  spec %s\n",
 337                             curnode->name);
 338                 for (curfsnode = dirnode->next; curfsnode != NULL;
 339                     curfsnode = curfsnode->next) {
 340 #if 0   /* too verbose for now */
 341                         if (debug & DEBUG_APPLY_SPECENTRY)
 342                                 printf("apply_specdir:  dirent %s\n",
 343                                     curfsnode->name);
 344 #endif
 345                         if (strcmp(curnode->name, curfsnode->name) == 0)
 346                                 break;
 347                 }
 348                 if (snprintf(path, sizeof(path), "%s/%s",
 349                     dir, curnode->name) >= sizeof(path))
 350                         errx(1, "Pathname too long.");
 351                 if (curfsnode == NULL) {        /* need new entry */
 352                         struct stat     stbuf;
 353
 354                                             /*
 355                                              * don't add optional spec entries
 356                                              * that lack an existing fs entry
 357                                              */
 358                         if ((curnode->flags & F_OPT) &&
 359                             lstat(path, &stbuf) == -1)
 360                                         continue;
 361
 362                                         /* check that enough info is provided */
 363 #define NODETEST(t, m)                                                  \
 364                         if (!(t))                                       \
 365                                 errx(1, "`%s': %s not provided", path, m)
 366                         NODETEST(curnode->flags & F_TYPE, "type");
 367                         NODETEST(curnode->flags & F_MODE, "mode");
 368                                 /* XXX: require F_TIME ? */
 369                         NODETEST(curnode->flags & F_GID ||
 370                             curnode->flags & F_GNAME, "group");
 371                         NODETEST(curnode->flags & F_UID ||
 372                             curnode->flags & F_UNAME, "user");
 373 /*                      if (curnode->type == F_BLOCK || curnode->type == F_CHAR)
 374                                 NODETEST(curnode->flags & F_DEV,
 375                                     "device number");*/
 376 #undef NODETEST
 377
 378                         if (debug & DEBUG_APPLY_SPECFILE)
 379                                 printf("apply_specdir: adding %s\n",
 380                                     curnode->name);
 381                                         /* build minimal fsnode */
 382                         memset(&stbuf, 0, sizeof(stbuf));
 383                         stbuf.st_mode = nodetoino(curnode->type);
 384                         stbuf.st_nlink = 1;
 385                         stbuf.st_mtime = stbuf.st_atime =
 386                             stbuf.st_ctime = start_time.tv_sec;
 387 #if HAVE_STRUCT_STAT_ST_MTIMENSEC
 388                         stbuf.st_mtimensec = stbuf.st_atimensec =
 389                             stbuf.st_ctimensec = start_time.tv_nsec;
 390 #endif
 391                         curfsnode = create_fsnode(curnode->name, &stbuf);
 392                         curfsnode->parent = dirnode->parent;
 393                         curfsnode->first = dirnode;
 394                         curfsnode->next = dirnode->next;
 395                         dirnode->next = curfsnode;
 396                         if (curfsnode->type == S_IFDIR) {
 397                                         /* for dirs, make "." entry as well */
 398                                 curfsnode->child = create_fsnode(".", &stbuf);
 399                                 curfsnode->child->parent = curfsnode;
 400                                 curfsnode->child->first = curfsnode->child;
 401                         }
 402                         if (curfsnode->type == S_IFLNK) {
 403                                 assert(curnode->slink != NULL);
 404                                         /* for symlinks, copy the target */
 405                                 if ((curfsnode->symlink =
 406                                     strdup(curnode->slink)) == NULL)
 407                                         err(1, "Memory allocation error");
 408                         }
 409                 }
 410                 apply_specentry(dir, curnode, curfsnode);
 411                 if (curnode->type == F_DIR) {
 412                         if (curfsnode->type != S_IFDIR)
 413                                 errx(1, "`%s' is not a directory", path);
 414                         assert (curfsnode->child != NULL);
 415                         apply_specdir(path, curnode, curfsnode->child, speconly);
 416                 }
 417         }
 418 }
 419
 420 static void
 421 apply_specentry(const char *dir, NODE *specnode, fsnode *dirnode)
 422 {
 423
 424         assert(specnode != NULL);
 425         assert(dirnode != NULL);
 426
 427         if (nodetoino(specnode->type) != dirnode->type)
 428                 errx(1, "`%s/%s' type mismatch: specfile %s, tree %s",
 429                     dir, specnode->name, inode_type(nodetoino(specnode->type)),
 430                     inode_type(dirnode->type));
 431
 432         if (debug & DEBUG_APPLY_SPECENTRY)
 433                 printf("apply_specentry: %s/%s\n", dir, dirnode->name);
 434
 435 #define ASEPRINT(t, b, o, n) \
 436                 if (debug & DEBUG_APPLY_SPECENTRY) \
 437                         printf("\t\t\tchanging %s from " b " to " b "\n", \
 438                             t, o, n)
 439
 440         if (specnode->flags & (F_GID | F_GNAME)) {
 441                 ASEPRINT("gid", "%d",
 442                     dirnode->inode->st.st_gid, specnode->st_gid);
 443                 dirnode->inode->st.st_gid = specnode->st_gid;
 444         }
 445         if (specnode->flags & F_MODE) {
 446                 ASEPRINT("mode", "%#o",
 447                     dirnode->inode->st.st_mode & ALLPERMS, specnode->st_mode);
 448                 dirnode->inode->st.st_mode &= ~ALLPERMS;
 449                 dirnode->inode->st.st_mode |= (specnode->st_mode & ALLPERMS);
 450         }
 451                 /* XXX: ignoring F_NLINK for now */
 452         if (specnode->flags & F_SIZE) {
 453                 ASEPRINT("size", "%lld",
 454                     (long long)dirnode->inode->st.st_size,
 455                     (long long)specnode->st_size);
 456                 dirnode->inode->st.st_size = specnode->st_size;
 457         }
 458         if (specnode->flags & F_SLINK) {
 459                 assert(dirnode->symlink != NULL);
 460                 assert(specnode->slink != NULL);
 461                 ASEPRINT("symlink", "%s", dirnode->symlink, specnode->slink);
 462                 free(dirnode->symlink);
 463                 if ((dirnode->symlink = strdup(specnode->slink)) == NULL)
 464                         err(1, "Memory allocation error");
 465         }
 466         if (specnode->flags & F_TIME) {
 467                 ASEPRINT("time", "%ld",
 468                     (long)dirnode->inode->st.st_mtime,
 469                     (long)specnode->st_mtimespec.tv_sec);
 470                 dirnode->inode->st.st_mtime =           specnode->st_mtimespec.tv_sec;
 471                 dirnode->inode->st.st_atime =           specnode->st_mtimespec.tv_sec;
 472                 dirnode->inode->st.st_ctime =           start_time.tv_sec;
 473 #if HAVE_STRUCT_STAT_ST_MTIMENSEC
 474                 dirnode->inode->st.st_mtimensec =       specnode->st_mtimespec.tv_nsec;
 475                 dirnode->inode->st.st_atimensec =       specnode->st_mtimespec.tv_nsec;
 476                 dirnode->inode->st.st_ctimensec =       start_time.tv_nsec;
 477 #endif
 478         }
 479         if (specnode->flags & (F_UID | F_UNAME)) {
 480                 ASEPRINT("uid", "%d",
 481                     dirnode->inode->st.st_uid, specnode->st_uid);
 482                 dirnode->inode->st.st_uid = specnode->st_uid;
 483         }
 484 #if HAVE_STRUCT_STAT_ST_FLAGS
 485         if (specnode->flags & F_FLAGS) {
 486                 ASEPRINT("flags", "%#lX",
 487                     (unsigned long)dirnode->inode->st.st_flags,
 488                     (unsigned long)specnode->st_flags);
 489                 dirnode->inode->st.st_flags = specnode->st_flags;
 490         }
 491 #endif
 492 /*      if (specnode->flags & F_DEV) {
 493                 ASEPRINT("rdev", "%#llx",
 494                     (unsigned long long)dirnode->inode->st.st_rdev,
 495                     (unsigned long long)specnode->st_rdev);
 496                 dirnode->inode->st.st_rdev = specnode->st_rdev;
 497         }*/
 498 #undef ASEPRINT
 499
 500         dirnode->flags |= FSNODE_F_HASSPEC;
 501 }
 502
 503
 504 /*
 505  * dump_fsnodes --
 506  *      dump the fsnodes from `cur', based in the directory `dir'
 507  */
 508 void
 509 dump_fsnodes(const char *dir, fsnode *root)
 510 {
 511         fsnode  *cur;
 512         char    path[MAXPATHLEN + 1];
 513
 514         assert (dir != NULL);
 515         printf("dump_fsnodes: %s %p\n", dir, root);
 516         for (cur = root; cur != NULL; cur = cur->next) {
 517                 if (snprintf(path, sizeof(path), "%s/%s", dir, cur->name)
 518                     >= sizeof(path))
 519                         errx(1, "Pathname too long.");
 520
 521                 if (debug & DEBUG_DUMP_FSNODES_VERBOSE)
 522                         printf("cur=%8p parent=%8p first=%8p ",
 523                             cur, cur->parent, cur->first);
 524                 printf("%7s: %s", inode_type(cur->type), path);
 525                 if (S_ISLNK(cur->type)) {
 526                         assert(cur->symlink != NULL);
 527                         printf(" -> %s", cur->symlink);
 528                 } else {
 529                         assert (cur->symlink == NULL);
 530                 }
 531                 if (cur->inode->nlink > 1)
 532                         printf(", nlinks=%d", cur->inode->nlink);
 533                 putchar('\n');
 534
 535                 if (cur->child) {
 536                         assert (cur->type == S_IFDIR);
 537                         dump_fsnodes(path, cur->child);
 538                 }
 539         }
 540         printf("dump_fsnodes: finished %s\n", dir);
 541 }
 542
 543
 544 /*
 545  * inode_type --
 546  *      for a given inode type `mode', return a descriptive string.
 547  *      for most cases, uses inotype() from mtree/misc.c
 548  */
 549 const char *
 550 inode_type(mode_t mode)
 551 {
 552         if (S_ISREG(mode))
 553                 return ("file");
 554         if (S_ISLNK(mode))
 555                 return ("symlink");
 556         if (S_ISDIR(mode))
 557                 return ("dir");
 558         if (S_ISLNK(mode))
 559                 return ("link");
 560         if (S_ISFIFO(mode))
 561                 return ("fifo");
 562         if (S_ISSOCK(mode))
 563                 return ("socket");
 564         /* XXX should not happen but handle them */
 565         if (S_ISCHR(mode))
 566                 return ("char");
 567         if (S_ISBLK(mode))
 568                 return ("block");
 569         return ("unknown");
 570 }
 571
 572
 573 /*
 574  * link_check --
 575  *      return pointer to fsinode matching `entry's st_ino & st_dev if it exists,
 576  *      otherwise add `entry' to table and return NULL
 577  */
 578 /* This was borrowed from du.c and tweaked to keep an fsnode
 579  * pointer instead. -- dbj@netbsd.org
 580  */
 581 static fsinode *
 582 link_check(fsinode *entry)
 583 {
 584         static struct entry {
 585                 fsinode *data;
 586         } *htable;
 587         static int htshift;  /* log(allocated size) */
 588         static int htmask;   /* allocated size - 1 */
 589         static int htused;   /* 2*number of insertions */
 590         int h, h2;
 591         uint64_t tmp;
 592         /* this constant is (1<<64)/((1+sqrt(5))/2)
 593          * aka (word size)/(golden ratio)
 594          */
 595         const uint64_t HTCONST = 11400714819323198485ULL;
 596         const int HTBITS = 64;
 597
 598         /* Never store zero in hashtable */
 599         assert(entry);
 600
 601         /* Extend hash table if necessary, keep load under 0.5 */
 602         if (htused<<1 >= htmask) {
 603                 struct entry *ohtable;
 604
 605                 if (!htable)
 606                         htshift = 10;   /* starting hashtable size */
 607                 else
 608                         htshift++;   /* exponential hashtable growth */
 609
 610                 htmask  = (1 << htshift) - 1;
 611                 htused = 0;
 612
 613                 ohtable = htable;
 614                 htable = calloc(htmask+1, sizeof(*htable));
 615                 if (!htable)
 616                         err(1, "Memory allocation error");
 617
 618                 /* populate newly allocated hashtable */
 619                 if (ohtable) {
 620                         int i;
 621                         for (i = 0; i <= htmask>>1; i++)
 622                                 if (ohtable[i].data)
 623                                         link_check(ohtable[i].data);
 624                         free(ohtable);
 625                 }
 626         }
 627
 628         /* multiplicative hashing */
 629         tmp = entry->st.st_dev;
 630         tmp <<= HTBITS>>1;
 631         tmp |=  entry->st.st_ino;
 632         tmp *= HTCONST;
 633         h  = tmp >> (HTBITS - htshift);
 634         h2 = 1 | ( tmp >> (HTBITS - (htshift<<1) - 1)); /* must be odd */
 635
 636         /* open address hashtable search with double hash probing */
 637         while (htable[h].data) {
 638                 if ((htable[h].data->st.st_ino == entry->st.st_ino) &&
 639                     (htable[h].data->st.st_dev == entry->st.st_dev)) {
 640                         return htable[h].data;
 641                 }
 642                 h = (h + h2) & htmask;
 643         }
 644
 645         /* Insert the current entry into hashtable */
 646         htable[h].data = entry;
 647         htused++;
 648         return NULL;
 649 }