summaryrefslogtreecommitdiff
path: root/nscd/netgroupcache.c
blob: edab1744f44601b82ee38dcb5efe9bce703b0af0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
/* Cache handling for netgroup lookup.
   Copyright (C) 2011-2014 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published
   by the Free Software Foundation; version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, see <http://www.gnu.org/licenses/>.  */

#include <alloca.h>
#include <assert.h>
#include <errno.h>
#include <libintl.h>
#include <stdbool.h>
#include <unistd.h>
#include <sys/mman.h>

#include "../inet/netgroup.h"
#include "nscd.h"
#include "dbg_log.h"

#include <kernel-features.h>


/* This is the standard reply in case the service is disabled.  */
static const netgroup_response_header disabled =
{
  .version = NSCD_VERSION,
  .found = -1,
  .nresults = 0,
  .result_len = 0
};

/* This is the struct describing how to write this record.  */
const struct iovec netgroup_iov_disabled =
{
  .iov_base = (void *) &disabled,
  .iov_len = sizeof (disabled)
};


/* This is the standard reply in case we haven't found the dataset.  */
static const netgroup_response_header notfound =
{
  .version = NSCD_VERSION,
  .found = 0,
  .nresults = 0,
  .result_len = 0
};


struct dataset
{
  struct datahead head;
  netgroup_response_header resp;
  char strdata[0];
};

/* Sends a notfound message and prepares a notfound dataset to write to the
   cache.  Returns true if there was enough memory to allocate the dataset and
   returns the dataset in DATASETP, total bytes to write in TOTALP and the
   timeout in TIMEOUTP.  KEY_COPY is set to point to the copy of the key in the
   dataset. */
static bool
do_notfound (struct database_dyn *db, int fd, request_header *req,
	       const char *key, struct dataset **datasetp, ssize_t *totalp,
	       time_t *timeoutp, char **key_copy)
{
  struct dataset *dataset;
  ssize_t total;
  time_t timeout;
  bool cacheable = false;

  total = sizeof (notfound);
  timeout = time (NULL) + db->negtimeout;

  if (fd != -1)
    TEMP_FAILURE_RETRY (send (fd, &notfound, total, MSG_NOSIGNAL));

  dataset = mempool_alloc (db, sizeof (struct dataset) + req->key_len, 1);
  /* If we cannot permanently store the result, so be it.  */
  if (dataset != NULL)
    {
      timeout = datahead_init_neg (&dataset->head,
				   sizeof (struct dataset) + req->key_len,
				   total, db->negtimeout);

      /* This is the reply.  */
      memcpy (&dataset->resp, &notfound, total);

      /* Copy the key data.  */
      memcpy (dataset->strdata, key, req->key_len);
      *key_copy = dataset->strdata;

      cacheable = true;
    }
  *timeoutp = timeout;
  *totalp = total;
  *datasetp = dataset;
  return cacheable;
}

static time_t
addgetnetgrentX (struct database_dyn *db, int fd, request_header *req,
		 const char *key, uid_t uid, struct hashentry *he,
		 struct datahead *dh, struct dataset **resultp)
{
  if (__glibc_unlikely (debug_level > 0))
    {
      if (he == NULL)
	dbg_log (_("Haven't found \"%s\" in netgroup cache!"), key);
      else
	dbg_log (_("Reloading \"%s\" in netgroup cache!"), key);
    }

  static service_user *netgroup_database;
  time_t timeout;
  struct dataset *dataset;
  bool cacheable = false;
  ssize_t total;
  bool found = false;

  char *key_copy = NULL;
  struct __netgrent data;
  size_t buflen = MAX (1024, sizeof (*dataset) + req->key_len);
  size_t buffilled = sizeof (*dataset);
  char *buffer = NULL;
  size_t nentries = 0;
  size_t group_len = strlen (key) + 1;
  union
  {
    struct name_list elem;
    char mem[sizeof (struct name_list) + group_len];
  } first_needed;

  if (netgroup_database == NULL
      && __nss_database_lookup ("netgroup", NULL, NULL, &netgroup_database))
    {
      /* No such service.  */
      cacheable = do_notfound (db, fd, req, key, &dataset, &total, &timeout,
			       &key_copy);
      goto writeout;
    }

  memset (&data, '\0', sizeof (data));
  buffer = xmalloc (buflen);
  first_needed.elem.next = &first_needed.elem;
  memcpy (first_needed.elem.name, key, group_len);
  data.needed_groups = &first_needed.elem;

  while (data.needed_groups != NULL)
    {
      /* Add the next group to the list of those which are known.  */
      struct name_list *this_group = data.needed_groups->next;
      if (this_group == data.needed_groups)
	data.needed_groups = NULL;
      else
	data.needed_groups->next = this_group->next;
      this_group->next = data.known_groups;
      data.known_groups = this_group;

      union
      {
	enum nss_status (*f) (const char *, struct __netgrent *);
	void *ptr;
      } setfct;

      service_user *nip = netgroup_database;
      int no_more = __nss_lookup (&nip, "setnetgrent", NULL, &setfct.ptr);
      while (!no_more)
	{
	  enum nss_status status
	    = DL_CALL_FCT (*setfct.f, (data.known_groups->name, &data));

	  if (status == NSS_STATUS_SUCCESS)
	    {
	      found = true;
	      union
	      {
		enum nss_status (*f) (struct __netgrent *, char *, size_t,
				      int *);
		void *ptr;
	      } getfct;
	      getfct.ptr = __nss_lookup_function (nip, "getnetgrent_r");
	      if (getfct.f != NULL)
		while (1)
		  {
		    int e;
		    status = getfct.f (&data, buffer + buffilled,
				       buflen - buffilled - req->key_len, &e);
		    if (status == NSS_STATUS_SUCCESS)
		      {
			if (data.type == triple_val)
			  {
			    const char *nhost = data.val.triple.host;
			    const char *nuser = data.val.triple.user;
			    const char *ndomain = data.val.triple.domain;

			    size_t hostlen = strlen (nhost ?: "") + 1;
			    size_t userlen = strlen (nuser ?: "") + 1;
			    size_t domainlen = strlen (ndomain ?: "") + 1;

			    if (nhost == NULL || nuser == NULL || ndomain == NULL
				|| nhost > nuser || nuser > ndomain)
			      {
				const char *last = nhost;
				if (last == NULL
				    || (nuser != NULL && nuser > last))
				  last = nuser;
				if (last == NULL
				    || (ndomain != NULL && ndomain > last))
				  last = ndomain;

				size_t bufused
				  = (last == NULL
				     ? buffilled
				     : last + strlen (last) + 1 - buffer);

				/* We have to make temporary copies.  */
				size_t needed = hostlen + userlen + domainlen;

				if (buflen - req->key_len - bufused < needed)
				  {
				    buflen += MAX (buflen, 2 * needed);
				    /* Save offset in the old buffer.  We don't
				       bother with the NULL check here since
				       we'll do that later anyway.  */
				    size_t nhostdiff = nhost - buffer;
				    size_t nuserdiff = nuser - buffer;
				    size_t ndomaindiff = ndomain - buffer;

				    char *newbuf = xrealloc (buffer, buflen);
				    /* Fix up the triplet pointers into the new
				       buffer.  */
				    nhost = (nhost ? newbuf + nhostdiff
					     : NULL);
				    nuser = (nuser ? newbuf + nuserdiff
					     : NULL);
				    ndomain = (ndomain ? newbuf + ndomaindiff
					       : NULL);
				    buffer = newbuf;
				  }

				nhost = memcpy (buffer + bufused,
						nhost ?: "", hostlen);
				nuser = memcpy ((char *) nhost + hostlen,
						nuser ?: "", userlen);
				ndomain = memcpy ((char *) nuser + userlen,
						  ndomain ?: "", domainlen);
			      }

			    char *wp = buffer + buffilled;
			    wp = memmove (wp, nhost ?: "", hostlen);
			    wp += hostlen;
			    wp = memmove (wp, nuser ?: "", userlen);
			    wp += userlen;
			    wp = memmove (wp, ndomain ?: "", domainlen);
			    wp += domainlen;
			    buffilled = wp - buffer;
			    ++nentries;
			  }
			else
			  {
			    /* Check that the group has not been
			       requested before.  */
			    struct name_list *runp = data.needed_groups;
			    if (runp != NULL)
			      while (1)
				{
				  if (strcmp (runp->name, data.val.group) == 0)
				    break;

				  runp = runp->next;
				  if (runp == data.needed_groups)
				    {
				      runp = NULL;
				      break;
				    }
				}

			    if (runp == NULL)
			      {
				runp = data.known_groups;
				while (runp != NULL)
				  if (strcmp (runp->name, data.val.group) == 0)
				    break;
				  else
				    runp = runp->next;
				}

			    if (runp == NULL)
			      {
				/* A new group is requested.  */
				size_t namelen = strlen (data.val.group) + 1;
				struct name_list *newg = alloca (sizeof (*newg)
								 + namelen);
				memcpy (newg->name, data.val.group, namelen);
				if (data.needed_groups == NULL)
				  data.needed_groups = newg->next = newg;
				else
				  {
				    newg->next = data.needed_groups->next;
				    data.needed_groups->next = newg;
				    data.needed_groups = newg;
				  }
			      }
			  }
		      }
		    else if (status == NSS_STATUS_TRYAGAIN && e == ERANGE)
		      {
			buflen *= 2;
			buffer = xrealloc (buffer, buflen);
		      }
		    else if (status == NSS_STATUS_RETURN
			     || status == NSS_STATUS_NOTFOUND
			     || status == NSS_STATUS_UNAVAIL)
		      /* This was either the last one for this group or the
			 group was empty or the NSS module had an internal
			 failure.  Look at next group if available.  */
		      break;
		  }

	      enum nss_status (*endfct) (struct __netgrent *);
	      endfct = __nss_lookup_function (nip, "endnetgrent");
	      if (endfct != NULL)
		(void) DL_CALL_FCT (*endfct, (&data));

	      break;
	    }

	  no_more = __nss_next2 (&nip, "setnetgrent", NULL, &setfct.ptr,
				 status, 0);
	}
    }

  /* No results.  Return a failure and write out a notfound record in the
     cache.  */
  if (!found)
    {
      cacheable = do_notfound (db, fd, req, key, &dataset, &total, &timeout,
			       &key_copy);
      goto writeout;
    }

  total = buffilled;

  /* Fill in the dataset.  */
  dataset = (struct dataset *) buffer;
  timeout = datahead_init_pos (&dataset->head, total + req->key_len,
			       total - offsetof (struct dataset, resp),
			       he == NULL ? 0 : dh->nreloads + 1,
			       db->postimeout);

  dataset->resp.version = NSCD_VERSION;
  dataset->resp.found = 1;
  dataset->resp.nresults = nentries;
  dataset->resp.result_len = buffilled - sizeof (*dataset);

  assert (buflen - buffilled >= req->key_len);
  key_copy = memcpy (buffer + buffilled, key, req->key_len);
  buffilled += req->key_len;

  /* Now we can determine whether on refill we have to create a new
     record or not.  */
  if (he != NULL)
    {
      assert (fd == -1);

      if (dataset->head.allocsize == dh->allocsize
	  && dataset->head.recsize == dh->recsize
	  && memcmp (&dataset->resp, dh->data,
		     dh->allocsize - offsetof (struct dataset, resp)) == 0)
	{
	  /* The data has not changed.  We will just bump the timeout
	     value.  Note that the new record has been allocated on
	     the stack and need not be freed.  */
	  dh->timeout = dataset->head.timeout;
	  dh->ttl = dataset->head.ttl;
	  ++dh->nreloads;
	  dataset = (struct dataset *) dh;

	  goto out;
	}
    }

  {
    struct dataset *newp
      = (struct dataset *) mempool_alloc (db, total + req->key_len, 1);
    if (__glibc_likely (newp != NULL))
      {
	/* Adjust pointer into the memory block.  */
	key_copy = (char *) newp + (key_copy - buffer);

	dataset = memcpy (newp, dataset, total + req->key_len);
	cacheable = true;

	if (he != NULL)
	  /* Mark the old record as obsolete.  */
	  dh->usable = false;
      }
  }

  if (he == NULL && fd != -1)
    {
      /* We write the dataset before inserting it to the database
	 since while inserting this thread might block and so would
	 unnecessarily let the receiver wait.  */
    writeout:
#ifdef HAVE_SENDFILE
      if (__builtin_expect (db->mmap_used, 1) && cacheable)
	{
	  assert (db->wr_fd != -1);
	  assert ((char *) &dataset->resp > (char *) db->data);
	  assert ((char *) dataset - (char *) db->head + total
		  <= (sizeof (struct database_pers_head)
		      + db->head->module * sizeof (ref_t)
		      + db->head->data_size));
# ifndef __ASSUME_SENDFILE
	  ssize_t written =
# endif
	    sendfileall (fd, db->wr_fd, (char *) &dataset->resp
			 - (char *) db->head, dataset->head.recsize);
# ifndef __ASSUME_SENDFILE
	  if (written == -1 && errno == ENOSYS)
	    goto use_write;
# endif
	}
      else
#endif
	{
#if defined HAVE_SENDFILE && !defined __ASSUME_SENDFILE
	use_write:
#endif
	  writeall (fd, &dataset->resp, dataset->head.recsize);
	}
    }

  if (cacheable)
    {
      /* If necessary, we also propagate the data to disk.  */
      if (db->persistent)
	{
	  // XXX async OK?
	  uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
	  msync ((void *) pval,
		 ((uintptr_t) dataset & pagesize_m1) + total + req->key_len,
		 MS_ASYNC);
	}

      (void) cache_add (req->type, key_copy, req->key_len, &dataset->head,
			true, db, uid, he == NULL);

      pthread_rwlock_unlock (&db->lock);

      /* Mark the old entry as obsolete.  */
      if (dh != NULL)
	dh->usable = false;
    }

 out:
  free (buffer);

  *resultp = dataset;

  return timeout;
}


static time_t
addinnetgrX (struct database_dyn *db, int fd, request_header *req,
	     char *key, uid_t uid, struct hashentry *he,
	     struct datahead *dh)
{
  const char *group = key;
  key = (char *) rawmemchr (key, '\0') + 1;
  size_t group_len = key - group - 1;
  const char *host = *key++ ? key : NULL;
  if (host != NULL)
    key = (char *) rawmemchr (key, '\0') + 1;
  const char *user = *key++ ? key : NULL;
  if (user != NULL)
    key = (char *) rawmemchr (key, '\0') + 1;
  const char *domain = *key++ ? key : NULL;

  if (__glibc_unlikely (debug_level > 0))
    {
      if (he == NULL)
	dbg_log (_("Haven't found \"%s (%s,%s,%s)\" in netgroup cache!"),
		 group, host ?: "", user ?: "", domain ?: "");
      else
	dbg_log (_("Reloading \"%s (%s,%s,%s)\" in netgroup cache!"),
		 group, host ?: "", user ?: "", domain ?: "");
    }

  struct dataset *result = (struct dataset *) cache_search (GETNETGRENT,
							    group, group_len,
							    db, uid);
  time_t timeout;
  if (result != NULL)
    timeout = result->head.timeout;
  else
    {
      request_header req_get =
	{
	  .type = GETNETGRENT,
	  .key_len = group_len
	};
      timeout = addgetnetgrentX (db, -1, &req_get, group, uid, NULL, NULL,
				 &result);
    }

  struct indataset
  {
    struct datahead head;
    innetgroup_response_header resp;
  } *dataset
      = (struct indataset *) mempool_alloc (db,
					    sizeof (*dataset) + req->key_len,
					    1);
  struct indataset dataset_mem;
  bool cacheable = true;
  if (__glibc_unlikely (dataset == NULL))
    {
      cacheable = false;
      dataset = &dataset_mem;
    }

  datahead_init_pos (&dataset->head, sizeof (*dataset) + req->key_len,
		     sizeof (innetgroup_response_header),
		     he == NULL ? 0 : dh->nreloads + 1, result->head.ttl);
  /* Set the notfound status and timeout based on the result from
     getnetgrent.  */
  dataset->head.notfound = result->head.notfound;
  dataset->head.timeout = timeout;

  dataset->resp.version = NSCD_VERSION;
  dataset->resp.found = result->resp.found;
  /* Until we find a matching entry the result is 0.  */
  dataset->resp.result = 0;

  char *key_copy = memcpy ((char *) (dataset + 1), group, req->key_len);

  if (dataset->resp.found)
    {
      const char *triplets = (const char *) (&result->resp + 1);

      for (nscd_ssize_t i = result->resp.nresults; i > 0; --i)
	{
	  bool success = true;

	  /* For the host, user and domain in each triplet, we assume success
	     if the value is blank because that is how the wildcard entry to
	     match anything is stored in the netgroup cache.  */
	  if (host != NULL && *triplets != '\0')
	    success = strcmp (host, triplets) == 0;
	  triplets = (const char *) rawmemchr (triplets, '\0') + 1;

	  if (success && user != NULL && *triplets != '\0')
	    success = strcmp (user, triplets) == 0;
	  triplets = (const char *) rawmemchr (triplets, '\0') + 1;

	  if (success && (domain == NULL || *triplets == '\0'
			  || strcmp (domain, triplets) == 0))
	    {
	      dataset->resp.result = 1;
	      break;
	    }
	  triplets = (const char *) rawmemchr (triplets, '\0') + 1;
	}
    }

  if (he != NULL && dh->data[0].innetgroupdata.result == dataset->resp.result)
    {
      /* The data has not changed.  We will just bump the timeout
	 value.  Note that the new record has been allocated on
	 the stack and need not be freed.  */
      dh->timeout = timeout;
      dh->ttl = dataset->head.ttl;
      ++dh->nreloads;
      return timeout;
    }

  if (he == NULL)
    {
      /* We write the dataset before inserting it to the database
	 since while inserting this thread might block and so would
	 unnecessarily let the receiver wait.  */
       assert (fd != -1);

#ifdef HAVE_SENDFILE
      if (__builtin_expect (db->mmap_used, 1) && cacheable)
	{
	  assert (db->wr_fd != -1);
	  assert ((char *) &dataset->resp > (char *) db->data);
	  assert ((char *) dataset - (char *) db->head + sizeof (*dataset)
		  <= (sizeof (struct database_pers_head)
		      + db->head->module * sizeof (ref_t)
		      + db->head->data_size));
# ifndef __ASSUME_SENDFILE
	  ssize_t written =
# endif
	    sendfileall (fd, db->wr_fd,
			 (char *) &dataset->resp - (char *) db->head,
			 sizeof (innetgroup_response_header));
# ifndef __ASSUME_SENDFILE
	  if (written == -1 && errno == ENOSYS)
	    goto use_write;
# endif
	}
      else
#endif
	{
#if defined HAVE_SENDFILE && !defined __ASSUME_SENDFILE
	use_write:
#endif
	  writeall (fd, &dataset->resp, sizeof (innetgroup_response_header));
	}
    }

  if (cacheable)
    {
      /* If necessary, we also propagate the data to disk.  */
      if (db->persistent)
	{
	  // XXX async OK?
	  uintptr_t pval = (uintptr_t) dataset & ~pagesize_m1;
	  msync ((void *) pval,
		 ((uintptr_t) dataset & pagesize_m1) + sizeof (*dataset)
		 + req->key_len,
		 MS_ASYNC);
	}

      (void) cache_add (req->type, key_copy, req->key_len, &dataset->head,
			true, db, uid, he == NULL);

      pthread_rwlock_unlock (&db->lock);

      /* Mark the old entry as obsolete.  */
      if (dh != NULL)
	dh->usable = false;
    }

  return timeout;
}


void
addgetnetgrent (struct database_dyn *db, int fd, request_header *req,
		void *key, uid_t uid)
{
  struct dataset *ignore;

  addgetnetgrentX (db, fd, req, key, uid, NULL, NULL, &ignore);
}


time_t
readdgetnetgrent (struct database_dyn *db, struct hashentry *he,
		  struct datahead *dh)
{
  request_header req =
    {
      .type = GETNETGRENT,
      .key_len = he->len
    };
  struct dataset *ignore;

  return addgetnetgrentX (db, -1, &req, db->data + he->key, he->owner, he, dh,
			  &ignore);
}


void
addinnetgr (struct database_dyn *db, int fd, request_header *req,
	    void *key, uid_t uid)
{
  addinnetgrX (db, fd, req, key, uid, NULL, NULL);
}


time_t
readdinnetgr (struct database_dyn *db, struct hashentry *he,
	      struct datahead *dh)
{
  request_header req =
    {
      .type = INNETGR,
      .key_len = he->len
    };

  return addinnetgrX (db, -1, &req, db->data + he->key, he->owner, he, dh);
}