src/stat_cache.c

   1 #include "first.h"
   2
   3 #include "log.h"
   4 #include "stat_cache.h"
   5 #include "fdevent.h"
   6 #include "etag.h"
   7
   8 #include <sys/types.h>
   9 #include <sys/stat.h>
  10
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include <errno.h>
  14 #include <unistd.h>
  15 #include <stdio.h>
  16 #include <fcntl.h>
  17 #include <assert.h>
  18
  19 #ifdef HAVE_ATTR_ATTRIBUTES_H
  20 # include <attr/attributes.h>
  21 #endif
  22
  23 #ifdef HAVE_SYS_EXTATTR_H
  24 # include <sys/extattr.h>
  25 #endif
  26
  27 #ifdef HAVE_FAM_H
  28 # include <fam.h>
  29 #endif
  30
  31 #include "sys-mmap.h"
  32
  33 /* NetBSD 1.3.x needs it */
  34 #ifndef MAP_FAILED
  35 # define MAP_FAILED -1
  36 #endif
  37
  38 #ifndef O_LARGEFILE
  39 # define O_LARGEFILE 0
  40 #endif
  41
  42 #ifndef HAVE_LSTAT
  43 # define lstat stat
  44 #endif
  45
  46 #if 0
  47 /* enables debug code for testing if all nodes in the stat-cache as accessable */
  48 #define DEBUG_STAT_CACHE
  49 #endif
  50
  51 /*
  52  * stat-cache
  53  *
  54  * we cache the stat() calls in our own storage
  55  * the directories are cached in FAM
  56  *
  57  * if we get a change-event from FAM, we increment the version in the FAM->dir mapping
  58  *
  59  * if the stat()-cache is queried we check if the version id for the directory is the
  60  * same and return immediatly.
  61  *
  62  *
  63  * What we need:
  64  *
  65  * - for each stat-cache entry we need a fast indirect lookup on the directory name
  66  * - for each FAMRequest we have to find the version in the directory cache (index as userdata)
  67  *
  68  * stat <<-> directory <-> FAMRequest
  69  *
  70  * if file is deleted, directory is dirty, file is rechecked ...
  71  * if directory is deleted, directory mapping is removed
  72  *
  73  * */
  74
  75 #ifdef HAVE_FAM_H
  76 typedef struct {
  77         FAMRequest *req;
  78
  79         buffer *name;
  80
  81         int version;
  82 } fam_dir_entry;
  83 #endif
  84
  85 /* the directory name is too long to always compare on it
  86  * - we need a hash
  87  * - the hash-key is used as sorting criteria for a tree
  88  * - a splay-tree is used as we can use the caching effect of it
  89  */
  90
  91 /* we want to cleanup the stat-cache every few seconds, let's say 10
  92  *
  93  * - remove entries which are outdated since 30s
  94  * - remove entries which are fresh but havn't been used since 60s
  95  * - if we don't have a stat-cache entry for a directory, release it from the monitor
  96  */
  97
  98 #ifdef DEBUG_STAT_CACHE
  99 typedef struct {
 100         int *ptr;
 101
 102         size_t used;
 103         size_t size;
 104 } fake_keys;
 105
 106 static fake_keys ctrl;
 107 #endif
 108
 109 stat_cache *stat_cache_init(void) {
 110         stat_cache *sc = NULL;
 111
 112         sc = calloc(1, sizeof(*sc));
 113         force_assert(NULL != sc);
 114
 115         sc->dir_name = buffer_init();
 116         sc->hash_key = buffer_init();
 117
 118 #ifdef HAVE_FAM_H
 119         sc->fam_fcce_ndx = -1;
 120 #endif
 121
 122 #ifdef DEBUG_STAT_CACHE
 123         ctrl.size = 0;
 124 #endif
 125
 126         return sc;
 127 }
 128
 129 static stat_cache_entry * stat_cache_entry_init(void) {
 130         stat_cache_entry *sce = NULL;
 131
 132         sce = calloc(1, sizeof(*sce));
 133         force_assert(NULL != sce);
 134
 135         sce->name = buffer_init();
 136         sce->etag = buffer_init();
 137         sce->content_type = buffer_init();
 138
 139         return sce;
 140 }
 141
 142 static void stat_cache_entry_free(void *data) {
 143         stat_cache_entry *sce = data;
 144         if (!sce) return;
 145
 146         buffer_free(sce->etag);
 147         buffer_free(sce->name);
 148         buffer_free(sce->content_type);
 149
 150         free(sce);
 151 }
 152
 153 #ifdef HAVE_FAM_H
 154 static fam_dir_entry * fam_dir_entry_init(void) {
 155         fam_dir_entry *fam_dir = NULL;
 156
 157         fam_dir = calloc(1, sizeof(*fam_dir));
 158         force_assert(NULL != fam_dir);
 159
 160         fam_dir->name = buffer_init();
 161
 162         return fam_dir;
 163 }
 164
 165 static void fam_dir_entry_free(FAMConnection *fc, void *data) {
 166         fam_dir_entry *fam_dir = data;
 167
 168         if (!fam_dir) return;
 169
 170         FAMCancelMonitor(fc, fam_dir->req);
 171
 172         buffer_free(fam_dir->name);
 173         free(fam_dir->req);
 174
 175         free(fam_dir);
 176 }
 177 #endif
 178
 179 void stat_cache_free(stat_cache *sc) {
 180         while (sc->files) {
 181                 int osize;
 182                 splay_tree *node = sc->files;
 183
 184                 osize = sc->files->size;
 185
 186                 stat_cache_entry_free(node->data);
 187                 sc->files = splaytree_delete(sc->files, node->key);
 188
 189                 force_assert(osize - 1 == splaytree_size(sc->files));
 190         }
 191
 192         buffer_free(sc->dir_name);
 193         buffer_free(sc->hash_key);
 194
 195 #ifdef HAVE_FAM_H
 196         while (sc->dirs) {
 197                 int osize;
 198                 splay_tree *node = sc->dirs;
 199
 200                 osize = sc->dirs->size;
 201
 202                 fam_dir_entry_free(&sc->fam, node->data);
 203                 sc->dirs = splaytree_delete(sc->dirs, node->key);
 204
 205                 if (osize == 1) {
 206                         force_assert(NULL == sc->dirs);
 207                 } else {
 208                         force_assert(osize == (sc->dirs->size + 1));
 209                 }
 210         }
 211
 212         if (-1 != sc->fam_fcce_ndx) {
 213                 /* fd events already gone */
 214                 sc->fam_fcce_ndx = -1;
 215
 216                 FAMClose(&sc->fam);
 217         }
 218 #endif
 219         free(sc);
 220 }
 221
 222 #if defined(HAVE_XATTR)
 223 static int stat_cache_attr_get(buffer *buf, char *name, char *xattrname) {
 224         int attrlen;
 225         int ret;
 226
 227         buffer_string_prepare_copy(buf, 1023);
 228         attrlen = buf->size - 1;
 229         if(0 == (ret = attr_get(name, xattrname, buf->ptr, &attrlen, 0))) {
 230                 buffer_commit(buf, attrlen);
 231         }
 232         return ret;
 233 }
 234 #elif defined(HAVE_EXTATTR)
 235 static int stat_cache_attr_get(buffer *buf, char *name, char *xattrname) {
 236         ssize_t attrlen;
 237
 238         buffer_string_prepare_copy(buf, 1023);
 239
 240         if (-1 != (attrlen = extattr_get_file(name, EXTATTR_NAMESPACE_USER, xattrname, buf->ptr, buf->size - 1))) {
 241                 buf->used = attrlen + 1;
 242                 buf->ptr[attrlen] = '\0';
 243                 return 0;
 244         }
 245         return -1;
 246 }
 247 #endif
 248
 249 /* the famous DJB hash function for strings */
 250 static uint32_t hashme(buffer *str) {
 251         uint32_t hash = 5381;
 252         const char *s;
 253         for (s = str->ptr; *s; s++) {
 254                 hash = ((hash << 5) + hash) + *s;
 255         }
 256
 257         hash &= ~(((uint32_t)1) << 31); /* strip the highest bit */
 258
 259         return hash;
 260 }
 261
 262 #ifdef HAVE_FAM_H
 263 handler_t stat_cache_handle_fdevent(server *srv, void *_fce, int revent) {
 264         size_t i;
 265         stat_cache *sc = srv->stat_cache;
 266         size_t events;
 267
 268         UNUSED(_fce);
 269         /* */
 270
 271         if (revent & FDEVENT_IN) {
 272                 events = FAMPending(&sc->fam);
 273
 274                 for (i = 0; i < events; i++) {
 275                         FAMEvent fe;
 276                         fam_dir_entry *fam_dir;
 277                         splay_tree *node;
 278                         int ndx, j;
 279
 280                         FAMNextEvent(&sc->fam, &fe);
 281
 282                         /* handle event */
 283
 284                         switch(fe.code) {
 285                         case FAMChanged:
 286                         case FAMDeleted:
 287                         case FAMMoved:
 288                                 /* if the filename is a directory remove the entry */
 289
 290                                 fam_dir = fe.userdata;
 291                                 fam_dir->version++;
 292
 293                                 /* file/dir is still here */
 294                                 if (fe.code == FAMChanged) break;
 295
 296                                 /* we have 2 versions, follow and no-follow-symlink */
 297
 298                                 for (j = 0; j < 2; j++) {
 299                                         buffer_copy_string(sc->hash_key, fe.filename);
 300                                         buffer_append_int(sc->hash_key, j);
 301
 302                                         ndx = hashme(sc->hash_key);
 303
 304                                         sc->dirs = splaytree_splay(sc->dirs, ndx);
 305                                         node = sc->dirs;
 306
 307                                         if (node && (node->key == ndx)) {
 308                                                 int osize = splaytree_size(sc->dirs);
 309
 310                                                 fam_dir_entry_free(&sc->fam, node->data);
 311                                                 sc->dirs = splaytree_delete(sc->dirs, ndx);
 312
 313                                                 force_assert(osize - 1 == splaytree_size(sc->dirs));
 314                                         }
 315                                 }
 316                                 break;
 317                         default:
 318                                 break;
 319                         }
 320                 }
 321         }
 322
 323         if (revent & FDEVENT_HUP) {
 324                 /* fam closed the connection */
 325                 fdevent_event_del(srv->ev, &(sc->fam_fcce_ndx), FAMCONNECTION_GETFD(&sc->fam));
 326                 fdevent_unregister(srv->ev, FAMCONNECTION_GETFD(&sc->fam));
 327
 328                 FAMClose(&sc->fam);
 329         }
 330
 331         return HANDLER_GO_ON;
 332 }
 333
 334 static int buffer_copy_dirname(buffer *dst, buffer *file) {
 335         size_t i;
 336
 337         if (buffer_string_is_empty(file)) return -1;
 338
 339         for (i = buffer_string_length(file); i > 0; i--) {
 340                 if (file->ptr[i] == '/') {
 341                         buffer_copy_string_len(dst, file->ptr, i);
 342                         return 0;
 343                 }
 344         }
 345
 346         return -1;
 347 }
 348 #endif
 349
 350 #ifdef HAVE_LSTAT
 351 static int stat_cache_lstat(server *srv, buffer *dname, struct stat *lst) {
 352         if (lstat(dname->ptr, lst) == 0) {
 353                 return S_ISLNK(lst->st_mode) ? 0 : 1;
 354         }
 355         else {
 356                 log_error_write(srv, __FILE__, __LINE__, "sbs",
 357                                 "lstat failed for:",
 358                                 dname, strerror(errno));
 359         };
 360         return -1;
 361 }
 362 #endif
 363
 364 /***
 365  *
 366  *
 367  *
 368  * returns:
 369  *  - HANDLER_FINISHED on cache-miss (don't forget to reopen the file)
 370  *  - HANDLER_ERROR on stat() failed -> see errno for problem
 371  */
 372
 373 handler_t stat_cache_get_entry(server *srv, connection *con, buffer *name, stat_cache_entry **ret_sce) {
 374 #ifdef HAVE_FAM_H
 375         fam_dir_entry *fam_dir = NULL;
 376         int dir_ndx = -1;
 377 #endif
 378         stat_cache_entry *sce = NULL;
 379         stat_cache *sc;
 380         struct stat st;
 381         size_t k;
 382         int fd;
 383         struct stat lst;
 384 #ifdef DEBUG_STAT_CACHE
 385         size_t i;
 386 #endif
 387
 388         int file_ndx;
 389
 390         *ret_sce = NULL;
 391
 392         /*
 393          * check if the directory for this file has changed
 394          */
 395
 396         sc = srv->stat_cache;
 397
 398         buffer_copy_buffer(sc->hash_key, name);
 399         buffer_append_int(sc->hash_key, con->conf.follow_symlink);
 400
 401         file_ndx = hashme(sc->hash_key);
 402         sc->files = splaytree_splay(sc->files, file_ndx);
 403
 404 #ifdef DEBUG_STAT_CACHE
 405         for (i = 0; i < ctrl.used; i++) {
 406                 if (ctrl.ptr[i] == file_ndx) break;
 407         }
 408 #endif
 409
 410         if (sc->files && (sc->files->key == file_ndx)) {
 411 #ifdef DEBUG_STAT_CACHE
 412                 /* it was in the cache */
 413                 force_assert(i < ctrl.used);
 414 #endif
 415
 416                 /* we have seen this file already and
 417                  * don't stat() it again in the same second */
 418
 419                 sce = sc->files->data;
 420
 421                 /* check if the name is the same, we might have a collision */
 422
 423                 if (buffer_is_equal(name, sce->name)) {
 424                         if (srv->srvconf.stat_cache_engine == STAT_CACHE_ENGINE_SIMPLE) {
 425                                 if (sce->stat_ts == srv->cur_ts) {
 426                                         *ret_sce = sce;
 427                                         return HANDLER_GO_ON;
 428                                 }
 429                         }
 430                 } else {
 431                         /* collision, forget about the entry */
 432                         sce = NULL;
 433                 }
 434         } else {
 435 #ifdef DEBUG_STAT_CACHE
 436                 if (i != ctrl.used) {
 437                         log_error_write(srv, __FILE__, __LINE__, "xSB",
 438                                 file_ndx, "was already inserted but not found in cache, ", name);
 439                 }
 440                 force_assert(i == ctrl.used);
 441 #endif
 442         }
 443
 444 #ifdef HAVE_FAM_H
 445         /* dir-check */
 446         if (srv->srvconf.stat_cache_engine == STAT_CACHE_ENGINE_FAM) {
 447                 if (0 != buffer_copy_dirname(sc->dir_name, name)) {
 448                         log_error_write(srv, __FILE__, __LINE__, "sb",
 449                                 "no '/' found in filename:", name);
 450                         return HANDLER_ERROR;
 451                 }
 452
 453                 buffer_copy_buffer(sc->hash_key, sc->dir_name);
 454                 buffer_append_int(sc->hash_key, con->conf.follow_symlink);
 455
 456                 dir_ndx = hashme(sc->hash_key);
 457
 458                 sc->dirs = splaytree_splay(sc->dirs, dir_ndx);
 459
 460                 if ((NULL != sc->dirs) && (sc->dirs->key == dir_ndx)) {
 461                         fam_dir = sc->dirs->data;
 462
 463                         /* check whether we got a collision */
 464                         if (buffer_is_equal(sc->dir_name, fam_dir->name)) {
 465                                 /* test whether a found file cache entry is still ok */
 466                                 if ((NULL != sce) && (fam_dir->version == sce->dir_version)) {
 467                                         /* the stat()-cache entry is still ok */
 468
 469                                         *ret_sce = sce;
 470                                         return HANDLER_GO_ON;
 471                                 }
 472                         } else {
 473                                 /* hash collision, forget about the entry */
 474                                 fam_dir = NULL;
 475                         }
 476                 }
 477         }
 478 #endif
 479
 480         /*
 481          * *lol*
 482          * - open() + fstat() on a named-pipe results in a (intended) hang.
 483          * - stat() if regular file + open() to see if we can read from it is better
 484          *
 485          * */
 486         if (-1 == stat(name->ptr, &st)) {
 487                 return HANDLER_ERROR;
 488         }
 489
 490
 491         if (S_ISREG(st.st_mode)) {
 492                 /* fix broken stat/open for symlinks to reg files with appended slash on freebsd,osx */
 493                 if (name->ptr[buffer_string_length(name) - 1] == '/') {
 494                         errno = ENOTDIR;
 495                         return HANDLER_ERROR;
 496                 }
 497
 498                 /* try to open the file to check if we can read it */
 499                 if (-1 == (fd = open(name->ptr, O_RDONLY))) {
 500                         return HANDLER_ERROR;
 501                 }
 502                 close(fd);
 503         }
 504
 505         if (NULL == sce) {
 506
 507                 sce = stat_cache_entry_init();
 508                 buffer_copy_buffer(sce->name, name);
 509
 510                 /* already splayed file_ndx */
 511                 if ((NULL != sc->files) && (sc->files->key == file_ndx)) {
 512                         /* hash collision: replace old entry */
 513                         stat_cache_entry_free(sc->files->data);
 514                         sc->files->data = sce;
 515                 } else {
 516                         int osize = splaytree_size(sc->files);
 517
 518                         sc->files = splaytree_insert(sc->files, file_ndx, sce);
 519                         force_assert(osize + 1 == splaytree_size(sc->files));
 520
 521 #ifdef DEBUG_STAT_CACHE
 522                         if (ctrl.size == 0) {
 523                                 ctrl.size = 16;
 524                                 ctrl.used = 0;
 525                                 ctrl.ptr = malloc(ctrl.size * sizeof(*ctrl.ptr));
 526                                 force_assert(NULL != ctrl.ptr);
 527                         } else if (ctrl.size == ctrl.used) {
 528                                 ctrl.size += 16;
 529                                 ctrl.ptr = realloc(ctrl.ptr, ctrl.size * sizeof(*ctrl.ptr));
 530                                 force_assert(NULL != ctrl.ptr);
 531                         }
 532
 533                         ctrl.ptr[ctrl.used++] = file_ndx;
 534 #endif
 535                 }
 536                 force_assert(sc->files);
 537                 force_assert(sc->files->data == sce);
 538         }
 539
 540         sce->st = st;
 541         sce->stat_ts = srv->cur_ts;
 542
 543         /* catch the obvious symlinks
 544          *
 545          * this is not a secure check as we still have a race-condition between
 546          * the stat() and the open. We can only solve this by
 547          * 1. open() the file
 548          * 2. fstat() the fd
 549          *
 550          * and keeping the file open for the rest of the time. But this can
 551          * only be done at network level.
 552          *
 553          * per default it is not a symlink
 554          * */
 555 #ifdef HAVE_LSTAT
 556         sce->is_symlink = 0;
 557
 558         /* we want to only check for symlinks if we should block symlinks.
 559          */
 560         if (!con->conf.follow_symlink) {
 561                 if (stat_cache_lstat(srv, name, &lst)  == 0) {
 562 #ifdef DEBUG_STAT_CACHE
 563                                 log_error_write(srv, __FILE__, __LINE__, "sb",
 564                                                 "found symlink", name);
 565 #endif
 566                                 sce->is_symlink = 1;
 567                 }
 568
 569                 /*
 570                  * we assume "/" can not be symlink, so
 571                  * skip the symlink stuff if our path is /
 572                  **/
 573                 else if (buffer_string_length(name) > 1) {
 574                         buffer *dname;
 575                         char *s_cur;
 576
 577                         dname = buffer_init();
 578                         buffer_copy_buffer(dname, name);
 579
 580                         while ((s_cur = strrchr(dname->ptr, '/'))) {
 581                                 buffer_string_set_length(dname, s_cur - dname->ptr);
 582                                 if (dname->ptr == s_cur) {
 583 #ifdef DEBUG_STAT_CACHE
 584                                         log_error_write(srv, __FILE__, __LINE__, "s", "reached /");
 585 #endif
 586                                         break;
 587                                 }
 588 #ifdef DEBUG_STAT_CACHE
 589                                 log_error_write(srv, __FILE__, __LINE__, "sbs",
 590                                                 "checking if", dname, "is a symlink");
 591 #endif
 592                                 if (stat_cache_lstat(srv, dname, &lst)  == 0) {
 593                                         sce->is_symlink = 1;
 594 #ifdef DEBUG_STAT_CACHE
 595                                         log_error_write(srv, __FILE__, __LINE__, "sb",
 596                                                         "found symlink", dname);
 597 #endif
 598                                         break;
 599                                 };
 600                         };
 601                         buffer_free(dname);
 602                 };
 603         };
 604 #endif
 605
 606         if (S_ISREG(st.st_mode)) {
 607                 /* determine mimetype */
 608                 buffer_reset(sce->content_type);
 609 #if defined(HAVE_XATTR) || defined(HAVE_EXTATTR)
 610                 if (con->conf.use_xattr) {
 611                         stat_cache_attr_get(sce->content_type, name->ptr, srv->srvconf.xattr_name->ptr);
 612                 }
 613 #endif
 614                 /* xattr did not set a content-type. ask the config */
 615                 if (buffer_string_is_empty(sce->content_type)) {
 616                         size_t namelen = buffer_string_length(name);
 617
 618                         for (k = 0; k < con->conf.mimetypes->used; k++) {
 619                                 data_string *ds = (data_string *)con->conf.mimetypes->data[k];
 620                                 buffer *type = ds->key;
 621                                 size_t typelen = buffer_string_length(type);
 622
 623                                 if (buffer_is_empty(type)) continue;
 624
 625                                 /* check if the right side is the same */
 626                                 if (typelen > namelen) continue;
 627
 628                                 if (0 == strncasecmp(name->ptr + namelen - typelen, type->ptr, typelen)) {
 629                                         buffer_copy_buffer(sce->content_type, ds->value);
 630                                         break;
 631                                 }
 632                         }
 633                 }
 634                 etag_create(sce->etag, &(sce->st), con->etag_flags);
 635         } else if (S_ISDIR(st.st_mode)) {
 636                 etag_create(sce->etag, &(sce->st), con->etag_flags);
 637         }
 638
 639 #ifdef HAVE_FAM_H
 640         if (srv->srvconf.stat_cache_engine == STAT_CACHE_ENGINE_FAM) {
 641                 /* is this directory already registered ? */
 642                 if (NULL == fam_dir) {
 643                         fam_dir = fam_dir_entry_init();
 644
 645                         buffer_copy_buffer(fam_dir->name, sc->dir_name);
 646
 647                         fam_dir->version = 1;
 648
 649                         fam_dir->req = calloc(1, sizeof(FAMRequest));
 650                         force_assert(NULL != fam_dir);
 651
 652                         if (0 != FAMMonitorDirectory(&sc->fam, fam_dir->name->ptr,
 653                                                      fam_dir->req, fam_dir)) {
 654
 655                                 log_error_write(srv, __FILE__, __LINE__, "sbsbs",
 656                                                 "monitoring dir failed:",
 657                                                 fam_dir->name,
 658                                                 "file:", name,
 659                                                 FamErrlist[FAMErrno]);
 660
 661                                 fam_dir_entry_free(&sc->fam, fam_dir);
 662                                 fam_dir = NULL;
 663                         } else {
 664                                 int osize = splaytree_size(sc->dirs);
 665
 666                                 /* already splayed dir_ndx */
 667                                 if ((NULL != sc->dirs) && (sc->dirs->key == dir_ndx)) {
 668                                         /* hash collision: replace old entry */
 669                                         fam_dir_entry_free(&sc->fam, sc->dirs->data);
 670                                         sc->dirs->data = fam_dir;
 671                                 } else {
 672                                         sc->dirs = splaytree_insert(sc->dirs, dir_ndx, fam_dir);
 673                                         force_assert(osize == (splaytree_size(sc->dirs) - 1));
 674                                 }
 675
 676                                 force_assert(sc->dirs);
 677                                 force_assert(sc->dirs->data == fam_dir);
 678                         }
 679                 }
 680
 681                 /* bind the fam_fc to the stat() cache entry */
 682
 683                 if (fam_dir) {
 684                         sce->dir_version = fam_dir->version;
 685                 }
 686         }
 687 #endif
 688
 689         *ret_sce = sce;
 690
 691         return HANDLER_GO_ON;
 692 }
 693
 694 int stat_cache_open_rdonly_fstat (server *srv, connection *con, buffer *name, struct stat *st) {
 695         /*(Note: O_NOFOLLOW affects only the final path segment, the target file,
 696          * not any intermediate symlinks along the path)*/
 697         #ifndef O_BINARY
 698         #define O_BINARY 0
 699         #endif
 700         #ifndef O_LARGEFILE
 701         #define O_LARGEFILE 0
 702         #endif
 703         #ifndef O_NOCTTY
 704         #define O_NOCTTY 0
 705         #endif
 706         #ifndef O_NONBLOCK
 707         #define O_NONBLOCK 0
 708         #endif
 709         #ifndef O_NOFOLLOW
 710         #define O_NOFOLLOW 0
 711         #endif
 712         const int oflags = O_BINARY | O_LARGEFILE | O_NOCTTY | O_NONBLOCK
 713                          | (con->conf.follow_symlink ? 0 : O_NOFOLLOW);
 714         const int fd = open(name->ptr, O_RDONLY | oflags);
 715         if (fd >= 0) {
 716                 if (0 == fstat(fd, st)) {
 717                         return fd;
 718                 } else {
 719                         close(fd);
 720                 }
 721         }
 722         UNUSED(srv); /*(might log_error_write(srv, ...) in the future)*/
 723         return -1;
 724 }
 725
 726 /**
 727  * remove stat() from cache which havn't been stat()ed for
 728  * more than 10 seconds
 729  *
 730  *
 731  * walk though the stat-cache, collect the ids which are too old
 732  * and remove them in a second loop
 733  */
 734
 735 static int stat_cache_tag_old_entries(server *srv, splay_tree *t, int *keys, size_t *ndx) {
 736         stat_cache_entry *sce;
 737
 738         if (!t) return 0;
 739
 740         stat_cache_tag_old_entries(srv, t->left, keys, ndx);
 741         stat_cache_tag_old_entries(srv, t->right, keys, ndx);
 742
 743         sce = t->data;
 744
 745         if (srv->cur_ts - sce->stat_ts > 2) {
 746                 keys[(*ndx)++] = t->key;
 747         }
 748
 749         return 0;
 750 }
 751
 752 int stat_cache_trigger_cleanup(server *srv) {
 753         stat_cache *sc;
 754         size_t max_ndx = 0, i;
 755         int *keys;
 756
 757         sc = srv->stat_cache;
 758
 759         if (!sc->files) return 0;
 760
 761         keys = calloc(1, sizeof(int) * sc->files->size);
 762         force_assert(NULL != keys);
 763
 764         stat_cache_tag_old_entries(srv, sc->files, keys, &max_ndx);
 765
 766         for (i = 0; i < max_ndx; i++) {
 767                 int ndx = keys[i];
 768                 splay_tree *node;
 769
 770                 sc->files = splaytree_splay(sc->files, ndx);
 771
 772                 node = sc->files;
 773
 774                 if (node && (node->key == ndx)) {
 775 #ifdef DEBUG_STAT_CACHE
 776                         size_t j;
 777                         int osize = splaytree_size(sc->files);
 778                         stat_cache_entry *sce = node->data;
 779 #endif
 780                         stat_cache_entry_free(node->data);
 781                         sc->files = splaytree_delete(sc->files, ndx);
 782
 783 #ifdef DEBUG_STAT_CACHE
 784                         for (j = 0; j < ctrl.used; j++) {
 785                                 if (ctrl.ptr[j] == ndx) {
 786                                         ctrl.ptr[j] = ctrl.ptr[--ctrl.used];
 787                                         break;
 788                                 }
 789                         }
 790
 791                         force_assert(osize - 1 == splaytree_size(sc->files));
 792 #endif
 793                 }
 794         }
 795
 796         free(keys);
 797
 798         return 0;
 799 }