nscd/netgroupcache.c

   1 /* Cache handling for netgroup lookup.
   2    Copyright (C) 2011-2013 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published
   8    by the Free Software Foundation; version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, see <http://www.gnu.org/licenses/>.  */
  18
  19 #include <alloca.h>
  20 #include <assert.h>
  21 #include <errno.h>
  22 #include <libintl.h>
  23 #include <stdbool.h>
  24 #include <unistd.h>
  25 #include <sys/mman.h>
  26
  27 #include "../inet/netgroup.h"
  28 #include "nscd.h"
  29 #include "dbg_log.h"
  30
  31 #include <kernel-features.h>
  32
  33
  34 /* This is the standard reply in case the service is disabled.  */
  35 static const netgroup_response_header disabled =
  36 {
  37   .version = NSCD_VERSION,
  38   .found = -1,
  39   .nresults = 0,
  40   .result_len = 0
  41 };
  42
  43 /* This is the struct describing how to write this record.  */
  44 const struct iovec netgroup_iov_disabled =
  45 {
  46   .iov_base = (void *) &disabled,
  47   .iov_len = sizeof (disabled)
  48 };
  49
  50
  51 /* This is the standard reply in case we haven't found the dataset.  */
  52 static const netgroup_response_header notfound =
  53 {
  54   .version = NSCD_VERSION,
  55   .found = 0,
  56   .nresults = 0,
  57   .result_len = 0
  58 };
  59
  60
  61 struct dataset
  62 {
  63   struct datahead head;
  64   netgroup_response_header resp;
  65   char strdata[0];
  66 };
  67
  68
  69 static time_t
  70 addgetnetgrentX (struct database_dyn *db, int fd, request_header *req,
  71                  const char *key, uid_t uid, struct hashentry *he,
  72                  struct datahead *dh, struct dataset **resultp)
  73 {
  74   if (__builtin_expect (debug_level > 0, 0))
  75     {
  76       if (he == NULL)
  77         dbg_log (_("Haven't found \"%s\" in netgroup cache!"), key);
  78       else
  79         dbg_log (_("Reloading \"%s\" in netgroup cache!"), key);
  80     }
  81
  82   static service_user *netgroup_database;
  83   time_t timeout;
  84   struct dataset *dataset;
  85   bool cacheable = false;
  86   ssize_t total;
  87
  88   char *key_copy = NULL;
  89   struct __netgrent data;
  90   size_t buflen = MAX (1024, sizeof (*dataset) + req->key_len);
  91   size_t buffilled = sizeof (*dataset);
  92   char *buffer = NULL;
  93   size_t nentries = 0;
  94   bool use_malloc = false;
  95   size_t group_len = strlen (key) + 1;
  96   union
  97   {
  98     struct name_list elem;
  99     char mem[sizeof (struct name_list) + group_len];
 100   } first_needed;
 101
 102   if (netgroup_database == NULL
 103       && __nss_database_lookup ("netgroup", NULL, NULL, &netgroup_database))
 104     {
 105       /* No such service.  */
 106       total = sizeof (notfound);
 107       timeout = time (NULL) + db->negtimeout;
 108
 109       if (fd != -1)
 110         TEMP_FAILURE_RETRY (send (fd, &notfound, total, MSG_NOSIGNAL));
 111
 112       dataset = mempool_alloc (db, sizeof (struct dataset) + req->key_len, 1);
 113       /* If we cannot permanently store the result, so be it.  */
 114       if (dataset != NULL)
 115         {
 116           dataset->head.allocsize = sizeof (struct dataset) + req->key_len;
 117           dataset->head.recsize = total;
 118           dataset->head.notfound = true;
 119           dataset->head.nreloads = 0;
 120           dataset->head.usable = true;
 121
 122           /* Compute the timeout time.  */
 123           timeout = dataset->head.timeout = time (NULL) + db->negtimeout;
 124           dataset->head.ttl = db->negtimeout;
 125
 126           /* This is the reply.  */
 127           memcpy (&dataset->resp, &notfound, total);
 128
 129           /* Copy the key data.  */
 130           memcpy (dataset->strdata, key, req->key_len);
 131
 132           cacheable = true;
 133         }
 134
 135       goto writeout;
 136     }
 137
 138   memset (&data, '\0', sizeof (data));
 139   buffer = alloca (buflen);
 140   first_needed.elem.next = &first_needed.elem;
 141   memcpy (first_needed.elem.name, key, group_len);
 142   data.needed_groups = &first_needed.elem;
 143
 144   while (data.needed_groups != NULL)
 145     {
 146       /* Add the next group to the list of those which are known.  */
 147       struct name_list *this_group = data.needed_groups->next;
 148       if (this_group == data.needed_groups)
 149         data.needed_groups = NULL;
 150       else
 151         data.needed_groups->next = this_group->next;
 152       this_group->next = data.known_groups;
 153       data.known_groups = this_group;
 154
 155       union
 156       {
 157         enum nss_status (*f) (const char *, struct __netgrent *);
 158         void *ptr;
 159       } setfct;
 160
 161       service_user *nip = netgroup_database;
 162       int no_more = __nss_lookup (&nip, "setnetgrent", NULL, &setfct.ptr);
 163       while (!no_more)
 164         {
 165           enum nss_status status
 166             = DL_CALL_FCT (*setfct.f, (data.known_groups->name, &data));
 167
 168           if (status == NSS_STATUS_SUCCESS)
 169             {
 170               union
 171               {
 172                 enum nss_status (*f) (struct __netgrent *, char *, size_t,
 173                                       int *);
 174                 void *ptr;
 175               } getfct;
 176               getfct.ptr = __nss_lookup_function (nip, "getnetgrent_r");
 177               if (getfct.f != NULL)
 178                 while (1)
 179                   {
 180                     int e;
 181                     status = getfct.f (&data, buffer + buffilled,
 182                                        buflen - buffilled, &e);
 183                     if (status == NSS_STATUS_RETURN)
 184                       /* This was the last one for this group.  Look
 185                          at next group if available.  */
 186                       break;
 187                     if (status == NSS_STATUS_SUCCESS)
 188                       {
 189                         if (data.type == triple_val)
 190                           {
 191                             const char *nhost = data.val.triple.host;
 192                             const char *nuser = data.val.triple.user;
 193                             const char *ndomain = data.val.triple.domain;
 194
 195                             if (nhost == NULL || nuser == NULL || ndomain == NULL
 196                                 || nhost > nuser || nuser > ndomain)
 197                               {
 198                                 const char *last = nhost;
 199                                 if (last == NULL
 200                                     || (nuser != NULL && nuser > last))
 201                                   last = nuser;
 202                                 if (last == NULL
 203                                     || (ndomain != NULL && ndomain > last))
 204                                   last = ndomain;
 205
 206                                 size_t bufused
 207                                   = (last == NULL
 208                                      ? buffilled
 209                                      : last + strlen (last) + 1 - buffer);
 210
 211                                 /* We have to make temporary copies.  */
 212                                 size_t hostlen = strlen (nhost ?: "") + 1;
 213                                 size_t userlen = strlen (nuser ?: "") + 1;
 214                                 size_t domainlen = strlen (ndomain ?: "") + 1;
 215                                 size_t needed = hostlen + userlen + domainlen;
 216
 217                                 if (buflen - req->key_len - bufused < needed)
 218                                   {
 219                                     size_t newsize = MAX (2 * buflen,
 220                                                           buflen + 2 * needed);
 221                                     if (use_malloc || newsize > 1024 * 1024)
 222                                       {
 223                                         buflen = newsize;
 224                                         char *newbuf = xrealloc (use_malloc
 225                                                                  ? buffer
 226                                                                  : NULL,
 227                                                                  buflen);
 228
 229                                         buffer = newbuf;
 230                                         use_malloc = true;
 231                                       }
 232                                     else
 233                                       extend_alloca (buffer, buflen, newsize);
 234                                   }
 235
 236                                 nhost = memcpy (buffer + bufused,
 237                                                 nhost ?: "", hostlen);
 238                                 nuser = memcpy ((char *) nhost + hostlen,
 239                                                 nuser ?: "", userlen);
 240                                 ndomain = memcpy ((char *) nuser + userlen,
 241                                                   ndomain ?: "", domainlen);
 242                               }
 243
 244                             char *wp = buffer + buffilled;
 245                             wp = stpcpy (wp, nhost) + 1;
 246                             wp = stpcpy (wp, nuser) + 1;
 247                             wp = stpcpy (wp, ndomain) + 1;
 248                             buffilled = wp - buffer;
 249                             ++nentries;
 250                           }
 251                         else
 252                           {
 253                             /* Check that the group has not been
 254                                requested before.  */
 255                             struct name_list *runp = data.needed_groups;
 256                             if (runp != NULL)
 257                               while (1)
 258                                 {
 259                                   if (strcmp (runp->name, data.val.group) == 0)
 260                                     break;
 261
 262                                   runp = runp->next;
 263                                   if (runp == data.needed_groups)
 264                                     {
 265                                       runp = NULL;
 266                                       break;
 267                                     }
 268                                 }
 269
 270                             if (runp == NULL)
 271                               {
 272                                 runp = data.known_groups;
 273                                 while (runp != NULL)
 274                                   if (strcmp (runp->name, data.val.group) == 0)
 275                                     break;
 276                                   else
 277                                     runp = runp->next;
 278                                 }
 279
 280                             if (runp == NULL)
 281                               {
 282                                 /* A new group is requested.  */
 283                                 size_t namelen = strlen (data.val.group) + 1;
 284                                 struct name_list *newg = alloca (sizeof (*newg)
 285                                                                  + namelen);
 286                                 memcpy (newg->name, data.val.group, namelen);
 287                                 if (data.needed_groups == NULL)
 288                                   data.needed_groups = newg->next = newg;
 289                                 else
 290                                   {
 291                                     newg->next = data.needed_groups->next;
 292                                     data.needed_groups->next = newg;
 293                                     data.needed_groups = newg;
 294                                   }
 295                               }
 296                           }
 297                       }
 298                     else if (status == NSS_STATUS_UNAVAIL && e == ERANGE)
 299                       {
 300                         size_t newsize = 2 * buflen;
 301                         if (use_malloc || newsize > 1024 * 1024)
 302                           {
 303                             buflen = newsize;
 304                             char *newbuf = xrealloc (use_malloc
 305                                                      ? buffer : NULL, buflen);
 306
 307                             buffer = newbuf;
 308                             use_malloc = true;
 309                           }
 310                         else
 311                           extend_alloca (buffer, buflen, newsize);
 312                       }
 313                   }
 314
 315               enum nss_status (*endfct) (struct __netgrent *);
 316               endfct = __nss_lookup_function (nip, "endnetgrent");
 317               if (endfct != NULL)
 318                 (void) DL_CALL_FCT (*endfct, (&data));
 319
 320               break;
 321             }
 322
 323           no_more = __nss_next2 (&nip, "setnetgrent", NULL, &setfct.ptr,
 324                                  status, 0);
 325         }
 326     }
 327
 328   total = buffilled;
 329
 330   /* Fill in the dataset.  */
 331   dataset = (struct dataset *) buffer;
 332   dataset->head.allocsize = total + req->key_len;
 333   dataset->head.recsize = total - offsetof (struct dataset, resp);
 334   dataset->head.notfound = false;
 335   dataset->head.nreloads = he == NULL ? 0 : (dh->nreloads + 1);
 336   dataset->head.usable = true;
 337   dataset->head.ttl = db->postimeout;
 338   timeout = dataset->head.timeout = time (NULL) + dataset->head.ttl;
 339
 340   dataset->resp.version = NSCD_VERSION;
 341   dataset->resp.found = 1;
 342   dataset->resp.nresults = nentries;
 343   dataset->resp.result_len = buffilled - sizeof (*dataset);
 344
 345   assert (buflen - buffilled >= req->key_len);
 346   key_copy = memcpy (buffer + buffilled, key, req->key_len);
 347   buffilled += req->key_len;
 348
 349   /* Now we can determine whether on refill we have to create a new
 350      record or not.  */
 351   if (he != NULL)
 352     {
 353       assert (fd == -1);
 354
 355       if (dataset->head.allocsize == dh->allocsize
 356           && dataset->head.recsize == dh->recsize
 357           && memcmp (&dataset->resp, dh->data,
 358                      dh->allocsize - offsetof (struct dataset, resp)) == 0)
 359         {
 360           /* The data has not changed.  We will just bump the timeout
 361              value.  Note that the new record has been allocated on
 362              the stack and need not be freed.  */
 363           dh->timeout = dataset->head.timeout;
 364           dh->ttl = dataset->head.ttl;
 365           ++dh->nreloads;
 366           dataset = (struct dataset *) dh;
 367
 368           goto out;
 369         }
 370     }
 371
 372   {
 373     struct dataset *newp
 374       = (struct dataset *) mempool_alloc (db, total + req->key_len, 1);
 375     if (__builtin_expect (newp != NULL, 1))
 376       {
 377         /* Adjust pointer into the memory block.  */
 378         key_copy = (char *) newp + (key_copy - buffer);
 379
 380         dataset = memcpy (newp, dataset, total + req->key_len);
 381         cacheable = true;
 382
 383         if (he != NULL)
 384           /* Mark the old record as obsolete.  */
 385           dh->usable = false;
 386       }
 387   }
 388
 389   if (he == NULL && fd != -1)
 390     {
 391       /* We write the dataset before inserting it to the database
 392          since while inserting this thread might block and so would
 393          unnecessarily let the receiver wait.  */
 394     writeout:
 395 #ifdef HAVE_SENDFILE
 396       if (__builtin_expect (db->mmap_used, 1) && cacheable)
 397         {
 398           assert (db->wr_fd != -1);
 399           assert ((char *) &dataset->resp > (char *) db->data);
 400           assert ((char *) dataset - (char *) db->head + total
 401                   <= (sizeof (struct database_pers_head)
 402                       + db->head->module * sizeof (ref_t)
 403                       + db->head->data_size));
 404 # ifndef __ASSUME_SENDFILE
 405           ssize_t written =
 406 # endif
 407             sendfileall (fd, db->wr_fd, (char *) &dataset->resp
 408                          - (char *) db->head, dataset->head.recsize);
 409 # ifndef __ASSUME_SENDFILE
 410           if (written == -1 && errno == ENOSYS)
 411             goto use_write;
 412 # endif
 413         }
 414       else
 415 #endif
 416         {
 417 #if defined HAVE_SENDFILE && !defined __ASSUME_SENDFILE
 418         use_write:
 419 #endif
 420           writeall (fd, &dataset->resp, dataset->head.recsize);
 421         }
 422     }
 423
 424   if (cacheable)
 425     {
 426       /* If necessary, we also propagate the data to disk.  */
 427       if (db->persistent)
 428         {
 429           // XXX async OK?
 430           uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
 431           msync ((void *) pval,
 432                  ((uintptr_t) dataset & pagesize_m1) + total + req->key_len,
 433                  MS_ASYNC);
 434         }
 435
 436       (void) cache_add (req->type, key_copy, req->key_len, &dataset->head,
 437                         true, db, uid, he == NULL);
 438
 439       pthread_rwlock_unlock (&db->lock);
 440
 441       /* Mark the old entry as obsolete.  */
 442       if (dh != NULL)
 443         dh->usable = false;
 444     }
 445
 446  out:
 447   if (use_malloc)
 448     free (buffer);
 449
 450   *resultp = dataset;
 451
 452   return timeout;
 453 }
 454
 455
 456 static time_t
 457 addinnetgrX (struct database_dyn *db, int fd, request_header *req,
 458              char *key, uid_t uid, struct hashentry *he,
 459              struct datahead *dh)
 460 {
 461   const char *group = key;
 462   key = (char *) rawmemchr (key, '\0') + 1;
 463   size_t group_len = key - group - 1;
 464   const char *host = *key++ ? key : NULL;
 465   if (host != NULL)
 466     key = (char *) rawmemchr (key, '\0') + 1;
 467   const char *user = *key++ ? key : NULL;
 468   if (user != NULL)
 469     key = (char *) rawmemchr (key, '\0') + 1;
 470   const char *domain = *key++ ? key : NULL;
 471
 472   if (__builtin_expect (debug_level > 0, 0))
 473     {
 474       if (he == NULL)
 475         dbg_log (_("Haven't found \"%s (%s,%s,%s)\" in netgroup cache!"),
 476                  group, host ?: "", user ?: "", domain ?: "");
 477       else
 478         dbg_log (_("Reloading \"%s (%s,%s,%s)\" in netgroup cache!"),
 479                  group, host ?: "", user ?: "", domain ?: "");
 480     }
 481
 482   struct dataset *result = (struct dataset *) cache_search (GETNETGRENT,
 483                                                             group, group_len,
 484                                                             db, uid);
 485   time_t timeout;
 486   if (result != NULL)
 487     timeout = result->head.timeout;
 488   else
 489     {
 490       request_header req_get =
 491         {
 492           .type = GETNETGRENT,
 493           .key_len = group_len
 494         };
 495       timeout = addgetnetgrentX (db, -1, &req_get, group, uid, NULL, NULL,
 496                                  &result);
 497     }
 498
 499   struct indataset
 500   {
 501     struct datahead head;
 502     innetgroup_response_header resp;
 503   } *dataset
 504       = (struct indataset *) mempool_alloc (db,
 505                                             sizeof (*dataset) + req->key_len,
 506                                             1);
 507   struct indataset dataset_mem;
 508   bool cacheable = true;
 509   if (__builtin_expect (dataset == NULL, 0))
 510     {
 511       cacheable = false;
 512       dataset = &dataset_mem;
 513     }
 514
 515   dataset->head.allocsize = sizeof (*dataset) + req->key_len;
 516   dataset->head.recsize = sizeof (innetgroup_response_header);
 517   dataset->head.notfound = result->head.notfound;
 518   dataset->head.nreloads = he == NULL ? 0 : (dh->nreloads + 1);
 519   dataset->head.usable = true;
 520   dataset->head.ttl = result->head.ttl;
 521   dataset->head.timeout = timeout;
 522
 523   dataset->resp.version = NSCD_VERSION;
 524   dataset->resp.found = result->resp.found;
 525   /* Until we find a matching entry the result is 0.  */
 526   dataset->resp.result = 0;
 527
 528   char *key_copy = memcpy ((char *) (dataset + 1), group, req->key_len);
 529
 530   if (dataset->resp.found)
 531     {
 532       const char *triplets = (const char *) (&result->resp + 1);
 533
 534       for (nscd_ssize_t i = result->resp.nresults; i > 0; --i)
 535         {
 536           bool success = true;
 537
 538           if (host != NULL)
 539             success = strcmp (host, triplets) == 0;
 540           triplets = (const char *) rawmemchr (triplets, '\0') + 1;
 541
 542           if (success && user != NULL)
 543             success = strcmp (user, triplets) == 0;
 544           triplets = (const char *) rawmemchr (triplets, '\0') + 1;
 545
 546           if (success && (domain == NULL || strcmp (domain, triplets) == 0))
 547             {
 548               dataset->resp.result = 1;
 549               break;
 550             }
 551           triplets = (const char *) rawmemchr (triplets, '\0') + 1;
 552         }
 553     }
 554
 555   if (he != NULL && dh->data[0].innetgroupdata.result == dataset->resp.result)
 556     {
 557       /* The data has not changed.  We will just bump the timeout
 558          value.  Note that the new record has been allocated on
 559          the stack and need not be freed.  */
 560       dh->timeout = timeout;
 561       dh->ttl = dataset->head.ttl;
 562       ++dh->nreloads;
 563       return timeout;
 564     }
 565
 566   if (he == NULL)
 567     {
 568       /* We write the dataset before inserting it to the database
 569          since while inserting this thread might block and so would
 570          unnecessarily let the receiver wait.  */
 571        assert (fd != -1);
 572
 573 #ifdef HAVE_SENDFILE
 574       if (__builtin_expect (db->mmap_used, 1) && cacheable)
 575         {
 576           assert (db->wr_fd != -1);
 577           assert ((char *) &dataset->resp > (char *) db->data);
 578           assert ((char *) dataset - (char *) db->head + sizeof (*dataset)
 579                   <= (sizeof (struct database_pers_head)
 580                       + db->head->module * sizeof (ref_t)
 581                       + db->head->data_size));
 582 # ifndef __ASSUME_SENDFILE
 583           ssize_t written =
 584 # endif
 585             sendfileall (fd, db->wr_fd,
 586                          (char *) &dataset->resp - (char *) db->head,
 587                          sizeof (innetgroup_response_header));
 588 # ifndef __ASSUME_SENDFILE
 589           if (written == -1 && errno == ENOSYS)
 590             goto use_write;
 591 # endif
 592         }
 593       else
 594         {
 595 # ifndef __ASSUME_SENDFILE
 596         use_write:
 597 # endif
 598 #endif
 599           writeall (fd, &dataset->resp, sizeof (innetgroup_response_header));
 600         }
 601     }
 602
 603   if (cacheable)
 604     {
 605       /* If necessary, we also propagate the data to disk.  */
 606       if (db->persistent)
 607         {
 608           // XXX async OK?
 609           uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
 610           msync ((void *) pval,
 611                  ((uintptr_t) dataset & pagesize_m1) + sizeof (*dataset)
 612                  + req->key_len,
 613                  MS_ASYNC);
 614         }
 615
 616       (void) cache_add (req->type, key_copy, req->key_len, &dataset->head,
 617                         true, db, uid, he == NULL);
 618
 619       pthread_rwlock_unlock (&db->lock);
 620
 621       /* Mark the old entry as obsolete.  */
 622       if (dh != NULL)
 623         dh->usable = false;
 624     }
 625
 626   return timeout;
 627 }
 628
 629
 630 void
 631 addgetnetgrent (struct database_dyn *db, int fd, request_header *req,
 632                 void *key, uid_t uid)
 633 {
 634   struct dataset *ignore;
 635
 636   addgetnetgrentX (db, fd, req, key, uid, NULL, NULL, &ignore);
 637 }
 638
 639
 640 time_t
 641 readdgetnetgrent (struct database_dyn *db, struct hashentry *he,
 642                   struct datahead *dh)
 643 {
 644   request_header req =
 645     {
 646       .type = GETNETGRENT,
 647       .key_len = he->len
 648     };
 649   struct dataset *ignore;
 650
 651   return addgetnetgrentX (db, -1, &req, db->data + he->key, he->owner, he, dh,
 652                           &ignore);
 653 }
 654
 655
 656 void
 657 addinnetgr (struct database_dyn *db, int fd, request_header *req,
 658             void *key, uid_t uid)
 659 {
 660   addinnetgrX (db, fd, req, key, uid, NULL, NULL);
 661 }
 662
 663
 664 time_t
 665 readdinnetgr (struct database_dyn *db, struct hashentry *he,
 666               struct datahead *dh)
 667 {
 668   request_header req =
 669     {
 670       .type = INNETGR,
 671       .key_len = he->len
 672     };
 673
 674   return addinnetgrX (db, -1, &req, db->data + he->key, he->owner, he, dh);
 675 }