summary refs log tree commit diff
path: root/nis/nss_compat/compat-grp.c
blob: c9750ae1be92e7489ff69c743219d08a6d8df48a (plain) (blame)
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
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
/* Copyright (C) 1996,1997,1998,1999,2001,2002 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Thorsten Kukuk <kukuk@suse.de>, 1996.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <errno.h>
#include <fcntl.h>
#include <nss.h>
#include <grp.h>
#include <ctype.h>
#include <bits/libc-lock.h>
#include <string.h>
#include <rpcsvc/yp.h>
#include <rpcsvc/ypclnt.h>
#include <rpcsvc/nis.h>
#include <nsswitch.h>

#include "nss-nisplus.h"
#include "nisplus-parser.h"

static service_user *ni;
static bool_t use_nisplus; /* default: group_compat: nis */
static nis_name grptable; /* Name of the group table */
static size_t grptablelen;

/* Get the declaration of the parser function.  */
#define ENTNAME grent
#define STRUCTURE group
#define EXTERN_PARSER
#include <nss/nss_files/files-parse.c>

/* Structure for remembering -group members ... */
#define BLACKLIST_INITIAL_SIZE 512
#define BLACKLIST_INCREMENT 256
struct blacklist_t
  {
    char *data;
    int current;
    int size;
  };

struct ent_t
  {
    bool_t nis;
    bool_t nis_first;
    char *oldkey;
    int oldkeylen;
    nis_result *result;
    FILE *stream;
    struct blacklist_t blacklist;
};
typedef struct ent_t ent_t;

static ent_t ext_ent = {0, 0, NULL, 0, NULL, NULL, {NULL, 0, 0}};

/* Protect global state against multiple changers.  */
__libc_lock_define_initialized (static, lock)

/* Prototypes for local functions.  */
static void blacklist_store_name (const char *, ent_t *);
static int in_blacklist (const char *, int, ent_t *);

static enum nss_status
_nss_first_init (void)
{
  if (ni == NULL)
    {
      __nss_database_lookup ("group_compat", NULL, "nis", &ni);
      use_nisplus = (strcmp (ni->name, "nisplus") == 0);
    }

  if (grptable == NULL)
    {
      static const char key[] = "group.org_dir.";
      const char *local_dir = nis_local_directory ();
      size_t len_local_dir = strlen (local_dir);

      grptable = malloc (sizeof (key) + len_local_dir);
      if (grptable == NULL)
        return NSS_STATUS_TRYAGAIN;

      grptablelen = ((char *) mempcpy (mempcpy (grptable,
						key, sizeof (key) - 1),
				       local_dir, len_local_dir + 1)
		     - grptable) - 1;
    }

  return NSS_STATUS_SUCCESS;
}

static enum nss_status
internal_setgrent (ent_t *ent)
{
  enum nss_status status = NSS_STATUS_SUCCESS;

  ent->nis = ent->nis_first = 0;

  if (_nss_first_init () != NSS_STATUS_SUCCESS)
    return NSS_STATUS_UNAVAIL;

  if (ent->oldkey != NULL)
    {
      free (ent->oldkey);
      ent->oldkey = NULL;
      ent->oldkeylen = 0;
    }

  if (ent->result != NULL)
    {
      nis_freeresult (ent->result);
      ent->result = NULL;
    }

  if (ent->blacklist.data != NULL)
    {
      ent->blacklist.current = 1;
      ent->blacklist.data[0] = '|';
      ent->blacklist.data[1] = '\0';
    }
  else
    ent->blacklist.current = 0;

  if (ent->stream == NULL)
    {
      ent->stream = fopen ("/etc/group", "r");

      if (ent->stream == NULL)
	status = errno == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
      else
	{
	  /* We have to make sure the file is  `closed on exec'.  */
	  int result, flags;

	  result = flags = fcntl (fileno (ent->stream), F_GETFD, 0);
	  if (result >= 0)
	    {
	      flags |= FD_CLOEXEC;
	      result = fcntl (fileno (ent->stream), F_SETFD, flags);
	    }
	  if (result < 0)
	    {
	      /* Something went wrong.  Close the stream and return a
		 failure.  */
	      fclose (ent->stream);
	      ent->stream = NULL;
	      status = NSS_STATUS_UNAVAIL;
	    }
	}
    }
  else
    rewind (ent->stream);

  return status;
}


enum nss_status
_nss_compat_setgrent (int stayopen)
{
  enum nss_status result;

  __libc_lock_lock (lock);

  result = internal_setgrent (&ext_ent);

  __libc_lock_unlock (lock);

  return result;
}


static enum nss_status
internal_endgrent (ent_t *ent)
{
  if (ent->stream != NULL)
    {
      fclose (ent->stream);
      ent->stream = NULL;
    }

  ent->nis = ent->nis_first = 0;

  if (ent->oldkey != NULL)
    {
      free (ent->oldkey);
      ent->oldkey = NULL;
      ent->oldkeylen = 0;
    }

  if (ent->result != NULL)
    {
      nis_freeresult (ent->result);
      ent->result = NULL;
    }

  if (ent->blacklist.data != NULL)
    {
      ent->blacklist.current = 1;
      ent->blacklist.data[0] = '|';
      ent->blacklist.data[1] = '\0';
    }
  else
    ent->blacklist.current = 0;

  return NSS_STATUS_SUCCESS;
}

enum nss_status
_nss_compat_endgrent (void)
{
  enum nss_status result;

  __libc_lock_lock (lock);

  result = internal_endgrent (&ext_ent);

  __libc_lock_unlock (lock);

  return result;
}

static enum nss_status
getgrent_next_nis (struct group *result, ent_t *ent, char *buffer,
		   size_t buflen, int *errnop)
{
  struct parser_data *data = (void *) buffer;
  char *domain;
  char *outkey, *outval;
  int outkeylen, outvallen, parse_res;
  char *p;

  if (yp_get_default_domain (&domain) != YPERR_SUCCESS)
    {
      ent->nis = 0;
      return NSS_STATUS_NOTFOUND;
    }

  do
    {
      char *save_oldkey;
      int save_oldlen;
      bool_t save_nis_first;

      if (ent->nis_first)
	{
	  if (yp_first (domain, "group.byname", &outkey, &outkeylen,
			&outval, &outvallen) != YPERR_SUCCESS)
	    {
	      ent->nis = 0;
	      return NSS_STATUS_UNAVAIL;
	    }

	  if ( buflen < ((size_t) outvallen + 1))
	    {
	      free (outval);
	      *errnop = ERANGE;
	      return NSS_STATUS_TRYAGAIN;
	    }

	  save_oldkey = ent->oldkey;
	  save_oldlen = ent->oldkeylen;
	  save_nis_first = TRUE;
	  ent->oldkey = outkey;
	  ent->oldkeylen = outkeylen;
	  ent->nis_first = FALSE;
	}
      else
	{
	  if (yp_next (domain, "group.byname", ent->oldkey, ent->oldkeylen,
		       &outkey, &outkeylen, &outval, &outvallen)
	      != YPERR_SUCCESS)
	    {
	      ent->nis = 0;
	      return NSS_STATUS_NOTFOUND;
	    }

	  if ( buflen < ((size_t) outvallen + 1))
	    {
	      free (outval);
	      *errnop = ERANGE;
	      return NSS_STATUS_TRYAGAIN;
	    }

	  save_oldkey = ent->oldkey;
	  save_oldlen = ent->oldkeylen;
	  save_nis_first = FALSE;
	  ent->oldkey = outkey;
	  ent->oldkeylen = outkeylen;
	}

      /* Copy the found data to our buffer...  */
      p = strncpy (buffer, outval, buflen);

      /* ...and free the data.  */
      free (outval);

      while (isspace (*p))
	++p;

      parse_res = _nss_files_parse_grent (p, result, data, buflen, errnop);
      if (parse_res == -1)
	{
	  free (ent->oldkey);
	  ent->oldkey = save_oldkey;
	  ent->oldkeylen = save_oldlen;
	  ent->nis_first = save_nis_first;
	  *errnop = ERANGE;
	  return NSS_STATUS_TRYAGAIN;
	}
      else
	{
	  if (!save_nis_first)
	    free (save_oldkey);
	}

      if (parse_res &&
	  in_blacklist (result->gr_name, strlen (result->gr_name), ent))
	parse_res = 0; /* if result->gr_name in blacklist,search next entry */
    }
  while (!parse_res);

  return NSS_STATUS_SUCCESS;
}

static enum nss_status
getgrent_next_nisplus (struct group *result, ent_t *ent, char *buffer,
                       size_t buflen, int *errnop)
{
  int parse_res;

  do
    {
      nis_result *save_oldres;
      bool_t save_nis_first;

      if (ent->nis_first)
        {
	  save_oldres = ent->result;
	  save_nis_first = TRUE;
          ent->result = nis_first_entry(grptable);
          if (niserr2nss (ent->result->status) != NSS_STATUS_SUCCESS)
            {
              ent->nis = 0;
              return niserr2nss (ent->result->status);
            }
          ent->nis_first = FALSE;
        }
      else
        {
          nis_result *res;

	  save_oldres = ent->result;
	  save_nis_first = FALSE;
          res = nis_next_entry(grptable, &ent->result->cookie);
          ent->result = res;
          if (niserr2nss (ent->result->status) != NSS_STATUS_SUCCESS)
            {
	      ent->nis = 0;
	      return niserr2nss (ent->result->status);
            }
        }
      parse_res = _nss_nisplus_parse_grent (ent->result, 0, result,
					    buffer, buflen, errnop);
      if (parse_res == -1)
	{
	  nis_freeresult (ent->result);
	  ent->result = save_oldres;
	  ent->nis_first = save_nis_first;
	  *errnop = ERANGE;
	  return NSS_STATUS_TRYAGAIN;
	}
      else
	{
	  if (!save_nis_first)
	    nis_freeresult (save_oldres);
	}

      if (parse_res &&
          in_blacklist (result->gr_name, strlen (result->gr_name), ent))
        parse_res = 0; /* if result->gr_name in blacklist,search next entry */
    }
  while (!parse_res);

  return NSS_STATUS_SUCCESS;
}

/* This function handle the +group entrys in /etc/group */
static enum nss_status
getgrnam_plusgroup (const char *name, struct group *result, char *buffer,
		    size_t buflen, int *errnop)
{
  struct parser_data *data = (void *) buffer;
  int parse_res;

  if (use_nisplus) /* Do the NIS+ query here */
    {
      nis_result *res;
      char buf[strlen (name) + 24 + grptablelen];

      sprintf(buf, "[name=%s],%s", name, grptable);
      res = nis_list(buf, FOLLOW_PATH | FOLLOW_LINKS, NULL, NULL);
      if (niserr2nss (res->status) != NSS_STATUS_SUCCESS)
        {
          enum nss_status status =  niserr2nss (res->status);

          nis_freeresult (res);
          return status;
        }
      parse_res = _nss_nisplus_parse_grent (res, 0, result, buffer, buflen,
					    errnop);
      if (parse_res == -1)
	{
	  nis_freeresult (res);
	  *errnop = ERANGE;
	  return NSS_STATUS_TRYAGAIN;
	}
      nis_freeresult (res);
    }
  else /* Use NIS */
    {
      char *domain, *outval, *p;
      int outvallen;

      if (yp_get_default_domain (&domain) != YPERR_SUCCESS)
	return NSS_STATUS_NOTFOUND;

      if (yp_match (domain, "group.byname", name, strlen (name),
		    &outval, &outvallen) != YPERR_SUCCESS)
	return NSS_STATUS_NOTFOUND;

      if (buflen < ((size_t) outvallen + 1))
	{
	  free (outval);
	  *errnop = ERANGE;
	  return NSS_STATUS_TRYAGAIN;
	}

      /* Copy the found data to our buffer...  */
      p = strncpy (buffer, outval, buflen);

      /* ... and free the data.  */
      free (outval);
      while (isspace (*p))
        ++p;
      parse_res = _nss_files_parse_grent (p, result, data, buflen, errnop);
      if (parse_res == -1)
	return NSS_STATUS_TRYAGAIN;
    }

  if (parse_res)
    /* We found the entry.  */
    return NSS_STATUS_SUCCESS;
  else
    return NSS_STATUS_RETURN;
}

static enum nss_status
getgrent_next_file (struct group *result, ent_t *ent,
		    char *buffer, size_t buflen, int *errnop)
{
  struct parser_data *data = (void *) buffer;
  while (1)
    {
      fpos_t pos;
      int parse_res = 0;
      char *p;

      do
	{
	  fgetpos (ent->stream, &pos);
	  buffer[buflen - 1] = '\xff';
	  p = fgets (buffer, buflen, ent->stream);
	  if (p == NULL && feof (ent->stream))
	    return NSS_STATUS_NOTFOUND;

	  if (p == NULL || buffer[buflen - 1] != '\xff')
	    {
	      fsetpos (ent->stream, &pos);
	      *errnop = ERANGE;
	      return NSS_STATUS_TRYAGAIN;
	    }

	  /* Terminate the line for any case.  */
	  buffer[buflen - 1] = '\0';

	  /* Skip leading blanks.  */
	  while (isspace (*p))
	    ++p;
	}
      while (*p == '\0' || *p == '#' || /* Ignore empty and comment lines. */
      /* Parse the line.  If it is invalid, loop to
         get the next line of the file to parse.  */
	     !(parse_res = _nss_files_parse_grent (p, result, data, buflen,
						   errnop)));

      if (parse_res == -1)
	{
	  /* The parser ran out of space.  */
	  fsetpos (ent->stream, &pos);
	  *errnop = ERANGE;
	  return NSS_STATUS_TRYAGAIN;
	}

      if (result->gr_name[0] != '+' && result->gr_name[0] != '-')
	/* This is a real entry.  */
	break;

      /* -group */
      if (result->gr_name[0] == '-' && result->gr_name[1] != '\0'
	  && result->gr_name[1] != '@')
	{
	  blacklist_store_name (&result->gr_name[1], ent);
	  continue;
	}

      /* +group */
      if (result->gr_name[0] == '+' && result->gr_name[1] != '\0'
	  && result->gr_name[1] != '@')
	{
          enum nss_status status;

	  /* Store the group in the blacklist for the "+" at the end of
	     /etc/group */
	  blacklist_store_name (&result->gr_name[1], ent);
	  status = getgrnam_plusgroup (&result->gr_name[1], result, buffer,
				       buflen, errnop);
          if (status == NSS_STATUS_SUCCESS) /* We found the entry. */
            break;
          else
            if (status == NSS_STATUS_RETURN /* We couldn't parse the entry */
		|| status == NSS_STATUS_NOTFOUND) /* No group in NIS */
              continue;
            else
	      {
		if (status == NSS_STATUS_TRYAGAIN)
		  {
		    /* The parser ran out of space.  */
		    fsetpos (ent->stream, &pos);
		    *errnop = ERANGE;
		  }
		return status;
	      }
	}

      /* +:... */
      if (result->gr_name[0] == '+' && result->gr_name[1] == '\0')
	{
	  ent->nis = TRUE;
	  ent->nis_first = TRUE;

	  if (use_nisplus)
	    return getgrent_next_nisplus (result, ent, buffer, buflen, errnop);
	  else
	    return getgrent_next_nis (result, ent, buffer, buflen, errnop);
	}
    }

  return NSS_STATUS_SUCCESS;
}


static enum nss_status
internal_getgrent_r (struct group *gr, ent_t *ent, char *buffer,
		     size_t buflen, int *errnop)
{
  if (ent->nis)
    {
      if (use_nisplus)
	return getgrent_next_nisplus (gr, ent, buffer, buflen, errnop);
      else
	return getgrent_next_nis (gr, ent, buffer, buflen, errnop);
    }
  else
    return getgrent_next_file (gr, ent, buffer, buflen, errnop);
}

enum nss_status
_nss_compat_getgrent_r (struct group *grp, char *buffer, size_t buflen,
			int *errnop)
{
  enum nss_status status = NSS_STATUS_SUCCESS;

  __libc_lock_lock (lock);

  /* Be prepared that the setgrent function was not called before.  */
  if (ext_ent.stream == NULL)
    status = internal_setgrent (&ext_ent);

  if (status == NSS_STATUS_SUCCESS)
    status = internal_getgrent_r (grp, &ext_ent, buffer, buflen, errnop);

  __libc_lock_unlock (lock);

  return status;
}

/* Searches in /etc/group and the NIS/NIS+ map for a special group */
static enum nss_status
internal_getgrnam_r (const char *name, struct group *result, ent_t *ent,
		     char *buffer, size_t buflen, int *errnop)
{
  struct parser_data *data = (void *) buffer;
  while (1)
    {
      fpos_t pos;
      int parse_res = 0;
      char *p;

      do
	{
	  fgetpos (ent->stream, &pos);
	  buffer[buflen - 1] = '\xff';
	  p = fgets (buffer, buflen, ent->stream);
	  if (p == NULL && feof (ent->stream))
	      return NSS_STATUS_NOTFOUND;

	  if (p == NULL || buffer[buflen - 1] != '\xff')
	    {
	      fsetpos (ent->stream, &pos);
	      *errnop = ERANGE;
	      return NSS_STATUS_TRYAGAIN;
	    }

	  /* Terminate the line for any case.  */
	  buffer[buflen - 1] = '\0';

	  /* Skip leading blanks.  */
	  while (isspace (*p))
	    ++p;
	}
      while (*p == '\0' || *p == '#' || /* Ignore empty and comment lines. */
      /* Parse the line.  If it is invalid, loop to
         get the next line of the file to parse.  */
	     !(parse_res = _nss_files_parse_grent (p, result, data, buflen,
						   errnop)));

      if (parse_res == -1)
	{
	  /* The parser ran out of space.  */
	  fsetpos (ent->stream, &pos);
	  *errnop = ERANGE;
	  return NSS_STATUS_TRYAGAIN;
	}

      /* This is a real entry.  */
      if (result->gr_name[0] != '+' && result->gr_name[0] != '-')
	{
	  if (strcmp (result->gr_name, name) == 0)
	    return NSS_STATUS_SUCCESS;
	  else
	    continue;
	}

      /* -group */
      if (result->gr_name[0] == '-' && result->gr_name[1] != '\0')
	{
	  if (strcmp (&result->gr_name[1], name) == 0)
	    return NSS_STATUS_NOTFOUND;
	  else
	    continue;
	}

      /* +group */
      if (result->gr_name[0] == '+' && result->gr_name[1] != '\0')
	{
	  if (strcmp (name, &result->gr_name[1]) == 0)
	    {
	      enum nss_status status;

	      status = getgrnam_plusgroup (name, result, buffer, buflen,
					   errnop);
	      if (status == NSS_STATUS_RETURN)
		/* We couldn't parse the entry */
		continue;
	      else
		return status;
	    }
	}
      /* +:... */
      if (result->gr_name[0] == '+' && result->gr_name[1] == '\0')
	{
	  enum nss_status status;

	  status = getgrnam_plusgroup (name, result, buffer, buflen, errnop);
	  if (status == NSS_STATUS_RETURN)
	    /* We couldn't parse the entry */
	    continue;
	  else
	    return status;
	}
    }

  return NSS_STATUS_SUCCESS;
}

enum nss_status
_nss_compat_getgrnam_r (const char *name, struct group *grp,
			char *buffer, size_t buflen, int *errnop)
{
  ent_t ent = {0, 0, NULL, 0, NULL, NULL, {NULL, 0, 0}};
  enum nss_status status;

  if (name[0] == '-' || name[0] == '+')
    return NSS_STATUS_NOTFOUND;

  __libc_lock_lock (lock);

  status = internal_setgrent (&ent);

  __libc_lock_unlock (lock);

  if (status != NSS_STATUS_SUCCESS)
    return status;

  status = internal_getgrnam_r (name, grp, &ent, buffer, buflen, errnop);

  internal_endgrent (&ent);

  return status;
}

/* This function handle the + entry in /etc/group */
static enum nss_status
getgrgid_plusgroup (gid_t gid, struct group *result, char *buffer,
		    size_t buflen, int *errnop)
{
  struct parser_data *data = (void *) buffer;
  int parse_res;

  if (use_nisplus) /* Do the NIS+ query here */
    {
      nis_result *res;
      char buf[24 + grptablelen];

      sprintf(buf, "[gid=%lu],%s", (unsigned long int) gid, grptable);
      res = nis_list(buf, FOLLOW_PATH | FOLLOW_LINKS, NULL, NULL);
      if (niserr2nss (res->status) != NSS_STATUS_SUCCESS)
        {
          enum nss_status status =  niserr2nss (res->status);

          nis_freeresult (res);
          return status;
        }
      if ((parse_res = _nss_nisplus_parse_grent (res, 0, result, buffer,
						 buflen, errnop)) == -1)
	{
	  nis_freeresult (res);
	  *errnop = ERANGE;
	  return NSS_STATUS_TRYAGAIN;
	}
      nis_freeresult (res);
    }
  else /* Use NIS */
    {
      char buf[24];
      char *domain, *outval, *p;
      int outvallen;

      if (yp_get_default_domain (&domain) != YPERR_SUCCESS)
	return NSS_STATUS_NOTFOUND;

      snprintf (buf, sizeof (buf), "%lu", (unsigned long int) gid);

      if (yp_match (domain, "group.bygid", buf, strlen (buf),
		    &outval, &outvallen) != YPERR_SUCCESS)
	return NSS_STATUS_NOTFOUND;

      if (buflen < ((size_t) outvallen + 1))
	{
	  free (outval);
	  *errnop = ERANGE;
	  return NSS_STATUS_TRYAGAIN;
	}

      /* Copy the found data to our buffer...  */
      p = strncpy (buffer, outval, buflen);

      /* ... and free the data.  */
      free (outval);

      while (isspace (*p))
        p++;
      parse_res = _nss_files_parse_grent (p, result, data, buflen, errnop);
      if (parse_res == -1)
	return NSS_STATUS_TRYAGAIN;
    }

  if (parse_res)
    /* We found the entry.  */
    return NSS_STATUS_SUCCESS;
  else
    return NSS_STATUS_RETURN;
}

/* Searches in /etc/group and the NIS/NIS+ map for a special group id */
static enum nss_status
internal_getgrgid_r (gid_t gid, struct group *result, ent_t *ent,
		     char *buffer, size_t buflen, int *errnop)
{
  struct parser_data *data = (void *) buffer;
  while (1)
    {
      fpos_t pos;
      int parse_res = 0;
      char *p;

      do
	{
	  fgetpos (ent->stream, &pos);
	  buffer[buflen - 1] = '\xff';
	  p = fgets (buffer, buflen, ent->stream);
	  if (p == NULL && feof (ent->stream))
	    return NSS_STATUS_NOTFOUND;

	  if (p == NULL || buffer[buflen - 1] != '\xff')
	    {
	      fsetpos (ent->stream, &pos);
	      *errnop = ERANGE;
	      return NSS_STATUS_TRYAGAIN;
	    }

	  /* Terminate the line for any case.  */
	  buffer[buflen - 1] = '\0';

	  /* Skip leading blanks.  */
	  while (isspace (*p))
	    ++p;
	}
      while (*p == '\0' || *p == '#' || /* Ignore empty and comment lines. */
      /* Parse the line.  If it is invalid, loop to
         get the next line of the file to parse.  */
	     !(parse_res = _nss_files_parse_grent (p, result, data, buflen,
						   errnop)));

      if (parse_res == -1)
	{
	  /* The parser ran out of space.  */
	  fsetpos (ent->stream, &pos);
	  *errnop = ERANGE;
	  return NSS_STATUS_TRYAGAIN;
	}

      /* This is a real entry.  */
      if (result->gr_name[0] != '+' && result->gr_name[0] != '-')
	{
	  if (result->gr_gid == gid)
	    return NSS_STATUS_SUCCESS;
	  else
	    continue;
	}

      /* -group */
      if (result->gr_name[0] == '-' && result->gr_name[1] != '\0')
	{
          blacklist_store_name (&result->gr_name[1], ent);
          continue;
	}

      /* +group */
      if (result->gr_name[0] == '+' && result->gr_name[1] != '\0')
	{
	  enum nss_status status;

	  /* Store the group in the blacklist for the "+" at the end of
             /etc/group */
          blacklist_store_name (&result->gr_name[1], ent);
	  status = getgrnam_plusgroup (&result->gr_name[1], result, buffer,
				      buflen, errnop);
	  if (status == NSS_STATUS_SUCCESS && result->gr_gid == gid)
	    break;
	  else
	    continue;
	}
      /* +:... */
      if (result->gr_name[0] == '+' && result->gr_name[1] == '\0')
	{
	  enum nss_status status;

	  status = getgrgid_plusgroup (gid, result, buffer, buflen, errnop);
	  if (status == NSS_STATUS_RETURN) /* We couldn't parse the entry */
	    return NSS_STATUS_NOTFOUND;
	  else
	    return status;
	}
    }

  return NSS_STATUS_SUCCESS;
}

enum nss_status
_nss_compat_getgrgid_r (gid_t gid, struct group *grp,
			char *buffer, size_t buflen, int *errnop)
{
  ent_t ent = {0, 0, NULL, 0, NULL, NULL, {NULL, 0, 0}};
  enum nss_status status;

  __libc_lock_lock (lock);

  status = internal_setgrent (&ent);

  __libc_lock_unlock (lock);

  if (status != NSS_STATUS_SUCCESS)
    return status;

  status = internal_getgrgid_r (gid, grp, &ent, buffer, buflen, errnop);

  internal_endgrent (&ent);

  return status;
}


/* Support routines for remembering -@netgroup and -user entries.
   The names are stored in a single string with `|' as separator. */
static void
blacklist_store_name (const char *name, ent_t *ent)
{
  int namelen = strlen (name);
  char *tmp;

  /* first call, setup cache */
  if (ent->blacklist.size == 0)
    {
      ent->blacklist.size = MAX (BLACKLIST_INITIAL_SIZE, 2 * namelen);
      ent->blacklist.data = malloc (ent->blacklist.size);
      if (ent->blacklist.data == NULL)
	return;
      ent->blacklist.data[0] = '|';
      ent->blacklist.data[1] = '\0';
      ent->blacklist.current = 1;
    }
  else
    {
      if (in_blacklist (name, namelen, ent))
	return;			/* no duplicates */

      if (ent->blacklist.current + namelen + 1 >= ent->blacklist.size)
	{
	  ent->blacklist.size += MAX (BLACKLIST_INCREMENT, 2 * namelen);
	  tmp = realloc (ent->blacklist.data, ent->blacklist.size);
	  if (tmp == NULL)
	    {
	      free (ent->blacklist.data);
	      ent->blacklist.size = 0;
	      return;
	    }
	  ent->blacklist.data = tmp;
	}
    }

  tmp = stpcpy (ent->blacklist.data + ent->blacklist.current, name);
  *tmp++ = '|';
  *tmp = '\0';
  ent->blacklist.current += namelen + 1;

  return;
}

/* returns TRUE if ent->blacklist contains name, else FALSE */
static bool_t
in_blacklist (const char *name, int namelen, ent_t *ent)
{
  char buf[namelen + 3];
  char *cp;

  if (ent->blacklist.data == NULL)
    return FALSE;

  buf[0] = '|';
  cp = stpcpy (&buf[1], name);
  *cp++= '|';
  *cp = '\0';
  return strstr (ent->blacklist.data, buf) != NULL;
}