summaryrefslogtreecommitdiff
path: root/libpwdgrp/pwd_grp.c
blob: 34690a738e554f3caff88d596c4593515a37117d (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
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
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
/* vi: set sw=4 ts=4: */
/*  Copyright (C) 2003     Manuel Novoa III
 *
 *  Licensed under GPL v2, or later.  See file LICENSE in this tarball.
 */

/*  Nov 6, 2003  Initial version.
 *
 *  NOTE: This implementation is quite strict about requiring all
 *    field seperators.  It also does not allow leading whitespace
 *    except when processing the numeric fields.  glibc is more
 *    lenient.  See the various glibc difference comments below.
 *
 *  TODO:
 *    Move to dynamic allocation of (currently statically allocated)
 *      buffers; especially for the group-related functions since
 *      large group member lists will cause error returns.
 *
 */

#include "libbb.h"
#include <assert.h>

#ifndef _PATH_SHADOW
#define	_PATH_SHADOW	"/etc/shadow"
#endif
#ifndef _PATH_PASSWD
#define	_PATH_PASSWD	"/etc/passwd"
#endif
#ifndef _PATH_GROUP
#define	_PATH_GROUP	"/etc/group"
#endif

/**********************************************************************/
/* Sizes for statically allocated buffers. */

/* If you change these values, also change _SC_GETPW_R_SIZE_MAX and
 * _SC_GETGR_R_SIZE_MAX in libc/unistd/sysconf.c to match */
#define PWD_BUFFER_SIZE 256
#define GRP_BUFFER_SIZE 256

/**********************************************************************/
/* Prototypes for internal functions. */

static int bb__pgsreader(
		int FAST_FUNC (*parserfunc)(void *d, char *line),
		void *data,
		char *__restrict line_buff,
		size_t buflen,
		FILE *f);

static int FAST_FUNC bb__parsepwent(void *pw, char *line);
static int FAST_FUNC bb__parsegrent(void *gr, char *line);
#if ENABLE_USE_BB_SHADOW
static int FAST_FUNC bb__parsespent(void *sp, char *line);
#endif

/**********************************************************************/
/* We avoid having big global data. */

struct statics {
	/* Smaller things first */
	struct passwd getpwuid_resultbuf;
	struct group getgrgid_resultbuf;
	struct passwd getpwnam_resultbuf;
	struct group getgrnam_resultbuf;

	char getpwuid_buffer[PWD_BUFFER_SIZE];
	char getgrgid_buffer[GRP_BUFFER_SIZE];
	char getpwnam_buffer[PWD_BUFFER_SIZE];
	char getgrnam_buffer[GRP_BUFFER_SIZE];
#if 0
	struct passwd fgetpwent_resultbuf;
	struct group fgetgrent_resultbuf;
	struct spwd fgetspent_resultbuf;
	char fgetpwent_buffer[PWD_BUFFER_SIZE];
	char fgetgrent_buffer[GRP_BUFFER_SIZE];
	char fgetspent_buffer[PWD_BUFFER_SIZE];
#endif
#if 0 //ENABLE_USE_BB_SHADOW
	struct spwd getspuid_resultbuf;
	struct spwd getspnam_resultbuf;
	char getspuid_buffer[PWD_BUFFER_SIZE];
	char getspnam_buffer[PWD_BUFFER_SIZE];
#endif
// Not converted - too small to bother
//pthread_mutex_t mylock = PTHREAD_MUTEX_INITIALIZER;
//FILE *pwf /*= NULL*/;
//FILE *grf /*= NULL*/;
//FILE *spf /*= NULL*/;
#if 0
	struct passwd getpwent_pwd;
	struct group getgrent_gr;
	char getpwent_line_buff[PWD_BUFFER_SIZE];
	char getgrent_line_buff[GRP_BUFFER_SIZE];
#endif
#if 0 //ENABLE_USE_BB_SHADOW
	struct spwd getspent_spwd;
	struct spwd sgetspent_spwd;
	char getspent_line_buff[PWD_BUFFER_SIZE];
	char sgetspent_line_buff[PWD_BUFFER_SIZE];
#endif
};

static struct statics *ptr_to_statics;

static struct statics *get_S(void)
{
	if (!ptr_to_statics)
		ptr_to_statics = xzalloc(sizeof(*ptr_to_statics));
	return ptr_to_statics;
}

/* Always use in this order, get_S() must be called first */
#define RESULTBUF(name) &((S = get_S())->name##_resultbuf)
#define BUFFER(name)    (S->name##_buffer)

/**********************************************************************/
/* For the various fget??ent_r funcs, return
 *
 *  0: success
 *  ENOENT: end-of-file encountered
 *  ERANGE: buflen too small
 *  other error values possible. See bb__pgsreader.
 *
 * Also, *result == resultbuf on success and NULL on failure.
 *
 * NOTE: glibc difference - For the ENOENT case, glibc also sets errno.
 *   We do not, as it really isn't an error if we reach the end-of-file.
 *   Doing so is analogous to having fgetc() set errno on EOF.
 */
/**********************************************************************/

int fgetpwent_r(FILE *__restrict stream, struct passwd *__restrict resultbuf,
				char *__restrict buffer, size_t buflen,
				struct passwd **__restrict result)
{
	int rv;

	*result = NULL;

	rv = bb__pgsreader(bb__parsepwent, resultbuf, buffer, buflen, stream);
	if (!rv) {
		*result = resultbuf;
	}

	return rv;
}

int fgetgrent_r(FILE *__restrict stream, struct group *__restrict resultbuf,
				char *__restrict buffer, size_t buflen,
				struct group **__restrict result)
{
	int rv;

	*result = NULL;

	rv = bb__pgsreader(bb__parsegrent, resultbuf, buffer, buflen, stream);
	if (!rv) {
		*result = resultbuf;
	}

	return rv;
}

#if ENABLE_USE_BB_SHADOW
#ifdef UNUSED_FOR_NOW
int fgetspent_r(FILE *__restrict stream, struct spwd *__restrict resultbuf,
				char *__restrict buffer, size_t buflen,
				struct spwd **__restrict result)
{
	int rv;

	*result = NULL;

	rv = bb__pgsreader(bb__parsespent, resultbuf, buffer, buflen, stream);
	if (!rv) {
		*result = resultbuf;
	}

	return rv;
}
#endif
#endif

/**********************************************************************/
/* For the various fget??ent funcs, return NULL on failure and a
 * pointer to the appropriate struct (statically allocated) on success.
 * TODO: audit & stop using these in bbox, they pull in static buffers */
/**********************************************************************/

#ifdef UNUSED_SINCE_WE_AVOID_STATIC_BUFS
struct passwd *fgetpwent(FILE *stream)
{
	struct statics *S;
	struct passwd *resultbuf = RESULTBUF(fgetpwent);
	char *buffer = BUFFER(fgetpwent);
	struct passwd *result;

	fgetpwent_r(stream, resultbuf, buffer, sizeof(BUFFER(fgetpwent)), &result);
	return result;
}

struct group *fgetgrent(FILE *stream)
{
	struct statics *S;
	struct group *resultbuf = RESULTBUF(fgetgrent);
	char *buffer = BUFFER(fgetgrent);
	struct group *result;

	fgetgrent_r(stream, resultbuf, buffer, sizeof(BUFFER(fgetgrent)), &result);
	return result;
}
#endif

#if ENABLE_USE_BB_SHADOW
#ifdef UNUSED_SINCE_WE_AVOID_STATIC_BUFS
struct spwd *fgetspent(FILE *stream)
{
	struct statics *S;
	struct spwd *resultbuf = RESULTBUF(fgetspent);
	char *buffer = BUFFER(fgetspent);
	struct spwd *result;

	fgetspent_r(stream, resultbuf, buffer, sizeof(BUFFER(fgetspent)), &result);
	return result;
}
#endif

#ifdef UNUSED_FOR_NOW
int sgetspent_r(const char *string, struct spwd *result_buf,
				char *buffer, size_t buflen, struct spwd **result)
{
	int rv = ERANGE;

	*result = NULL;

	if (buflen < PWD_BUFFER_SIZE) {
 DO_ERANGE:
		errno = rv;
		goto DONE;
	}

	if (string != buffer) {
		if (strlen(string) >= buflen) {
			goto DO_ERANGE;
		}
		strcpy(buffer, string);
	}

	rv = bb__parsespent(result_buf, buffer);
	if (!rv) {
		*result = result_buf;
	}

 DONE:
	return rv;
}
#endif
#endif /* ENABLE_USE_BB_SHADOW */

/**********************************************************************/

#define GETXXKEY_R_FUNC         getpwnam_r
#define GETXXKEY_R_PARSER       bb__parsepwent
#define GETXXKEY_R_ENTTYPE      struct passwd
#define GETXXKEY_R_TEST(ENT)    (!strcmp((ENT)->pw_name, key))
#define GETXXKEY_R_KEYTYPE      const char *__restrict
#define GETXXKEY_R_PATHNAME     _PATH_PASSWD
#include "pwd_grp_internal.c"

#define GETXXKEY_R_FUNC         getgrnam_r
#define GETXXKEY_R_PARSER       bb__parsegrent
#define GETXXKEY_R_ENTTYPE      struct group
#define GETXXKEY_R_TEST(ENT)    (!strcmp((ENT)->gr_name, key))
#define GETXXKEY_R_KEYTYPE      const char *__restrict
#define GETXXKEY_R_PATHNAME     _PATH_GROUP
#include "pwd_grp_internal.c"

#if ENABLE_USE_BB_SHADOW
#define GETXXKEY_R_FUNC         getspnam_r
#define GETXXKEY_R_PARSER       bb__parsespent
#define GETXXKEY_R_ENTTYPE      struct spwd
#define GETXXKEY_R_TEST(ENT)    (!strcmp((ENT)->sp_namp, key))
#define GETXXKEY_R_KEYTYPE      const char *__restrict
#define GETXXKEY_R_PATHNAME     _PATH_SHADOW
#include "pwd_grp_internal.c"
#endif

#define GETXXKEY_R_FUNC         getpwuid_r
#define GETXXKEY_R_PARSER       bb__parsepwent
#define GETXXKEY_R_ENTTYPE      struct passwd
#define GETXXKEY_R_TEST(ENT)    ((ENT)->pw_uid == key)
#define GETXXKEY_R_KEYTYPE      uid_t
#define GETXXKEY_R_PATHNAME     _PATH_PASSWD
#include "pwd_grp_internal.c"

#define GETXXKEY_R_FUNC         getgrgid_r
#define GETXXKEY_R_PARSER       bb__parsegrent
#define GETXXKEY_R_ENTTYPE      struct group
#define GETXXKEY_R_TEST(ENT)    ((ENT)->gr_gid == key)
#define GETXXKEY_R_KEYTYPE      gid_t
#define GETXXKEY_R_PATHNAME     _PATH_GROUP
#include "pwd_grp_internal.c"

/**********************************************************************/
/* TODO: audit & stop using these in bbox, they pull in static buffers */

/* This one has many users */
struct passwd *getpwuid(uid_t uid)
{
	struct statics *S;
	struct passwd *resultbuf = RESULTBUF(getpwuid);
	char *buffer = BUFFER(getpwuid);
	struct passwd *result;

	getpwuid_r(uid, resultbuf, buffer, sizeof(BUFFER(getpwuid)), &result);
	return result;
}

/* This one has many users */
struct group *getgrgid(gid_t gid)
{
	struct statics *S;
	struct group *resultbuf = RESULTBUF(getgrgid);
	char *buffer = BUFFER(getgrgid);
	struct group *result;

	getgrgid_r(gid, resultbuf, buffer, sizeof(BUFFER(getgrgid)), &result);
	return result;
}

#if 0 //ENABLE_USE_BB_SHADOW
/* This function is non-standard and is currently not built.  It seems
 * to have been created as a reentrant version of the non-standard
 * functions getspuid.  Why getspuid was added, I do not know. */
int getspuid_r(uid_t uid, struct spwd *__restrict resultbuf,
		       char *__restrict buffer, size_t buflen,
		       struct spwd **__restrict result)
{
	int rv;
	struct passwd *pp;
	struct passwd password;
	char pwd_buff[PWD_BUFFER_SIZE];

	*result = NULL;
	rv = getpwuid_r(uid, &password, pwd_buff, sizeof(pwd_buff), &pp);
	if (!rv) {
		rv = getspnam_r(password.pw_name, resultbuf, buffer, buflen, result);
	}

	return rv;
}

/* This function is non-standard and is currently not built.
 * Why it was added, I do not know. */
struct spwd *getspuid(uid_t uid)
{
	struct statics *S;
	struct spwd *resultbuf = RESULTBUF(getspuid);
	char *buffer = BUFFER(getspuid);
	struct spwd *result;

	getspuid_r(uid, resultbuf, buffer, sizeof(BUFFER(getspuid)), &result);
	return result;
}
#endif

/* This one has many users */
struct passwd *getpwnam(const char *name)
{
	struct statics *S;
	struct passwd *resultbuf = RESULTBUF(getpwnam);
	char *buffer = BUFFER(getpwnam);
	struct passwd *result;

	getpwnam_r(name, resultbuf, buffer, sizeof(BUFFER(getpwnam)), &result);
	return result;
}

/* This one has many users */
struct group *getgrnam(const char *name)
{
	struct statics *S;
	struct group *resultbuf = RESULTBUF(getgrnam);
	char *buffer = BUFFER(getgrnam);
	struct group *result;

	getgrnam_r(name, resultbuf, buffer, sizeof(BUFFER(getgrnam)), &result);
	return result;
}

#if 0 //ENABLE_USE_BB_SHADOW
struct spwd *getspnam(const char *name)
{
	struct statics *S;
	struct spwd *resultbuf = RESULTBUF(getspnam);
	char *buffer = BUFFER(getspnam);
	struct spwd *result;

	getspnam_r(name, resultbuf, buffer, sizeof(BUFFER(getspnam)), &result);
	return result;
}
#endif

/**********************************************************************/

/* FIXME: we don't have such CONFIG_xx - ?! */

#if defined CONFIG_USE_BB_THREADSAFE_SHADOW && defined PTHREAD_MUTEX_INITIALIZER
static pthread_mutex_t mylock = PTHREAD_MUTEX_INITIALIZER;
# define LOCK		pthread_mutex_lock(&mylock)
# define UNLOCK		pthread_mutex_unlock(&mylock);
#else
# define LOCK		((void) 0)
# define UNLOCK		((void) 0)
#endif

static FILE *pwf /*= NULL*/;
void setpwent(void)
{
	LOCK;
	if (pwf) {
		rewind(pwf);
	}
	UNLOCK;
}

void endpwent(void)
{
	LOCK;
	if (pwf) {
		fclose(pwf);
		pwf = NULL;
	}
	UNLOCK;
}


int getpwent_r(struct passwd *__restrict resultbuf,
			   char *__restrict buffer, size_t buflen,
			   struct passwd **__restrict result)
{
	int rv;

	LOCK;
	*result = NULL;				/* In case of error... */

	if (!pwf) {
		pwf = fopen_for_read(_PATH_PASSWD);
		if (!pwf) {
			rv = errno;
			goto ERR;
		}
	}

	rv = bb__pgsreader(bb__parsepwent, resultbuf, buffer, buflen, pwf);
	if (!rv) {
		*result = resultbuf;
	}

 ERR:
	UNLOCK;
	return rv;
}

static FILE *grf /*= NULL*/;
void setgrent(void)
{
	LOCK;
	if (grf) {
		rewind(grf);
	}
	UNLOCK;
}

void endgrent(void)
{
	LOCK;
	if (grf) {
		fclose(grf);
		grf = NULL;
	}
	UNLOCK;
}

int getgrent_r(struct group *__restrict resultbuf,
			   char *__restrict buffer, size_t buflen,
			   struct group **__restrict result)
{
	int rv;

	LOCK;
	*result = NULL;				/* In case of error... */

	if (!grf) {
		grf = fopen_for_read(_PATH_GROUP);
		if (!grf) {
			rv = errno;
			goto ERR;
		}
	}

	rv = bb__pgsreader(bb__parsegrent, resultbuf, buffer, buflen, grf);
	if (!rv) {
		*result = resultbuf;
	}

 ERR:
	UNLOCK;
	return rv;
}

#ifdef UNUSED_FOR_NOW
#if ENABLE_USE_BB_SHADOW
static FILE *spf /*= NULL*/;
void setspent(void)
{
	LOCK;
	if (spf) {
		rewind(spf);
	}
	UNLOCK;
}

void endspent(void)
{
	LOCK;
	if (spf) {
		fclose(spf);
		spf = NULL;
	}
	UNLOCK;
}

int getspent_r(struct spwd *resultbuf, char *buffer,
			   size_t buflen, struct spwd **result)
{
	int rv;

	LOCK;
	*result = NULL;				/* In case of error... */

	if (!spf) {
		spf = fopen_for_read(_PATH_SHADOW);
		if (!spf) {
			rv = errno;
			goto ERR;
		}
	}

	rv = bb__pgsreader(bb__parsespent, resultbuf, buffer, buflen, spf);
	if (!rv) {
		*result = resultbuf;
	}

 ERR:
	UNLOCK;
	return rv;
}
#endif
#endif /* UNUSED_FOR_NOW */

#ifdef UNUSED_SINCE_WE_AVOID_STATIC_BUFS
struct passwd *getpwent(void)
{
	static char line_buff[PWD_BUFFER_SIZE];
	static struct passwd pwd;
	struct passwd *result;

	getpwent_r(&pwd, line_buff, sizeof(line_buff), &result);
	return result;
}

struct group *getgrent(void)
{
	static char line_buff[GRP_BUFFER_SIZE];
	static struct group gr;
	struct group *result;

	getgrent_r(&gr, line_buff, sizeof(line_buff), &result);
	return result;
}

#if ENABLE_USE_BB_SHADOW
struct spwd *getspent(void)
{
	static char line_buff[PWD_BUFFER_SIZE];
	static struct spwd spwd;
	struct spwd *result;

	getspent_r(&spwd, line_buff, sizeof(line_buff), &result);
	return result;
}

struct spwd *sgetspent(const char *string)
{
	static char line_buff[PWD_BUFFER_SIZE];
	static struct spwd spwd;
	struct spwd *result;

	sgetspent_r(string, &spwd, line_buff, sizeof(line_buff), &result);
	return result;
}
#endif
#endif /* UNUSED_SINCE_WE_AVOID_STATIC_BUFS */

static gid_t *getgrouplist_internal(int *ngroups_ptr, const char *user, gid_t gid)
{
	FILE *grfile;
	gid_t *group_list;
	int ngroups;
	struct group group;
	char buff[PWD_BUFFER_SIZE];

	/* We alloc space for 8 gids at a time. */
	group_list = xmalloc(8 * sizeof(group_list[0]));
	group_list[0] = gid;
	ngroups = 1;

	grfile = fopen_for_read(_PATH_GROUP);
	if (grfile) {
		while (!bb__pgsreader(bb__parsegrent, &group, buff, sizeof(buff), grfile)) {
			char **m;
			assert(group.gr_mem); /* Must have at least a NULL terminator. */
			if (group.gr_gid == gid)
				continue;
			for (m = group.gr_mem; *m; m++) {
				if (strcmp(*m, user) != 0)
					continue;
				group_list = xrealloc_vector(group_list, /*8=2^3:*/ 3, ngroups);
				group_list[ngroups++] = group.gr_gid;
				break;
			}
		}
		fclose(grfile);
	}
	*ngroups_ptr = ngroups;
	return group_list;
}

int initgroups(const char *user, gid_t gid)
{
	int ngroups;
	gid_t *group_list = getgrouplist_internal(&ngroups, user, gid);

	ngroups = setgroups(ngroups, group_list);
	free(group_list);
	return ngroups;
}

int getgrouplist(const char *user, gid_t gid, gid_t *groups, int *ngroups)
{
	int ngroups_old = *ngroups;
	gid_t *group_list = getgrouplist_internal(ngroups, user, gid);

	if (*ngroups <= ngroups_old) {
		ngroups_old = *ngroups;
		memcpy(groups, group_list, ngroups_old * sizeof(groups[0]));
	} else {
		ngroups_old = -1;
	}
	free(group_list);
	return ngroups_old;
}

#ifdef UNUSED_SINCE_WE_AVOID_STATIC_BUFS
int putpwent(const struct passwd *__restrict p, FILE *__restrict f)
{
	int rv = -1;

#if 0
	/* glibc does this check */
	if (!p || !f) {
		errno = EINVAL;
		return rv;
	}
#endif

	/* No extra thread locking is needed above what fprintf does. */
	if (fprintf(f, "%s:%s:%lu:%lu:%s:%s:%s\n",
				p->pw_name, p->pw_passwd,
				(unsigned long)(p->pw_uid),
				(unsigned long)(p->pw_gid),
				p->pw_gecos, p->pw_dir, p->pw_shell) >= 0
		) {
		rv = 0;
	}

	return rv;
}

int putgrent(const struct group *__restrict p, FILE *__restrict f)
{
	int rv = -1;

#if 0
	/* glibc does this check */
	if (!p || !f) {
		errno = EINVAL;
		return rv;
	}
#endif

	if (fprintf(f, "%s:%s:%lu:",
				p->gr_name, p->gr_passwd,
				(unsigned long)(p->gr_gid)) >= 0
	) {
		static const char format[] ALIGN1 = ",%s";

		char **m;
		const char *fmt;

		fmt = format + 1;

		assert(p->gr_mem);
		m = p->gr_mem;

		while (1) {
			if (!*m) {
				if (fputc('\n', f) >= 0) {
					rv = 0;
				}
				break;
			}
			if (fprintf(f, fmt, *m) < 0) {
				break;
			}
			m++;
			fmt = format;
		}
	}

	return rv;
}
#endif

#if ENABLE_USE_BB_SHADOW
#ifdef UNUSED_FOR_NOW
static const unsigned char put_sp_off[] ALIGN1 = {
	offsetof(struct spwd, sp_lstchg),       /* 2 - not a char ptr */
	offsetof(struct spwd, sp_min),          /* 3 - not a char ptr */
	offsetof(struct spwd, sp_max),          /* 4 - not a char ptr */
	offsetof(struct spwd, sp_warn),         /* 5 - not a char ptr */
	offsetof(struct spwd, sp_inact),        /* 6 - not a char ptr */
	offsetof(struct spwd, sp_expire)        /* 7 - not a char ptr */
};

int putspent(const struct spwd *p, FILE *stream)
{
	const char *fmt;
	long x;
	int i;
	int rv = -1;

	/* Unlike putpwent and putgrent, glibc does not check the args. */
	if (fprintf(stream, "%s:%s:", p->sp_namp,
				(p->sp_pwdp ? p->sp_pwdp : "")) < 0
	) {
		goto DO_UNLOCK;
	}

	for (i = 0; i < sizeof(put_sp_off); i++) {
		fmt = "%ld:";
		x = *(long *)((char *)p + put_sp_off[i]);
		if (x == -1) {
			fmt += 3;
		}
		if (fprintf(stream, fmt, x) < 0) {
			goto DO_UNLOCK;
		}
	}

	if ((p->sp_flag != ~0UL) && (fprintf(stream, "%lu", p->sp_flag) < 0)) {
		goto DO_UNLOCK;
	}

	if (fputc('\n', stream) > 0) {
		rv = 0;
	}

 DO_UNLOCK:
	return rv;
}
#endif
#endif /* USE_BB_SHADOW */

/**********************************************************************/
/* Internal functions                                                 */
/**********************************************************************/

static const unsigned char pw_off[] ALIGN1 = {
	offsetof(struct passwd, pw_name),       /* 0 */
	offsetof(struct passwd, pw_passwd),     /* 1 */
	offsetof(struct passwd, pw_uid),        /* 2 - not a char ptr */
	offsetof(struct passwd, pw_gid),        /* 3 - not a char ptr */
	offsetof(struct passwd, pw_gecos),      /* 4 */
	offsetof(struct passwd, pw_dir),        /* 5 */
	offsetof(struct passwd, pw_shell)       /* 6 */
};

static int FAST_FUNC bb__parsepwent(void *data, char *line)
{
	char *endptr;
	char *p;
	int i;

	i = 0;
	while (1) {
		p = (char *) data + pw_off[i];

		if (i < 2 || i > 3) {
			*((char **) p) = line;
			if (i == 6) {
				return 0;
			}
			/* NOTE: glibc difference - glibc allows omission of
			 * ':' seperators after the gid field if all remaining
			 * entries are empty.  We require all separators. */
			line = strchr(line, ':');
			if (!line) {
				break;
			}
		} else {
			unsigned long t = strtoul(line, &endptr, 10);
			/* Make sure we had at least one digit, and that the
			 * failing char is the next field seperator ':'.  See
			 * glibc difference note above. */
			/* TODO: Also check for leading whitespace? */
			if ((endptr == line) || (*endptr != ':')) {
				break;
			}
			line = endptr;
			if (i & 1) {		/* i == 3 -- gid */
				*((gid_t *) p) = t;
			} else {			/* i == 2 -- uid */
				*((uid_t *) p) = t;
			}
		}

		*line++ = '\0';
		i++;
	} /* while (1) */

	return -1;
}

/**********************************************************************/

static const unsigned char gr_off[] ALIGN1 = {
	offsetof(struct group, gr_name),        /* 0 */
	offsetof(struct group, gr_passwd),      /* 1 */
	offsetof(struct group, gr_gid)          /* 2 - not a char ptr */
};

static int FAST_FUNC bb__parsegrent(void *data, char *line)
{
	char *endptr;
	char *p;
	int i;
	char **members;
	char *end_of_buf;

	end_of_buf = ((struct group *) data)->gr_name; /* Evil hack! */
	i = 0;
	while (1) {
		p = (char *) data + gr_off[i];

		if (i < 2) {
			*((char **) p) = line;
			line = strchr(line, ':');
			if (!line) {
				break;
			}
			*line++ = '\0';
			i++;
		} else {
			*((gid_t *) p) = strtoul(line, &endptr, 10);

			/* NOTE: glibc difference - glibc allows omission of the
			 * trailing colon when there is no member list.  We treat
			 * this as an error. */

			/* Make sure we had at least one digit, and that the
			 * failing char is the next field seperator ':'.  See
			 * glibc difference note above. */
			if ((endptr == line) || (*endptr != ':')) {
				break;
			}

			i = 1;				/* Count terminating NULL ptr. */
			p = endptr;

			if (p[1]) { /* We have a member list to process. */
				/* Overwrite the last ':' with a ',' before counting.
				 * This allows us to (1) test for initial ','
				 * and (2) adds one ',' so that the number of commas
				 * equals the member count. */
				*p = ',';
				do {
					/* NOTE: glibc difference - glibc allows and trims leading
					 * (but not trailing) space.  We treat this as an error. */
					/* NOTE: glibc difference - glibc allows consecutive and
					 * trailing commas, and ignores "empty string" users.  We
					 * treat this as an error. */
					if (*p == ',') {
						++i;
						*p = 0;	/* nul-terminate each member string. */
						if (!*++p || (*p == ',') || isspace(*p)) {
							goto ERR;
						}
					}
				} while (*++p);
			}

			/* Now align (p+1), rounding up. */
			/* Assumes sizeof(char **) is a power of 2. */
			members = (char **)( (((intptr_t) p) + sizeof(char **))
								 & ~((intptr_t)(sizeof(char **) - 1)) );

			if (((char *)(members + i)) > end_of_buf) {	/* No space. */
				break;
			}

			((struct group *) data)->gr_mem = members;

			if (--i) {
				p = endptr;	/* Pointing to char prior to first member. */
				while (1) {
					*members++ = ++p;
					if (!--i)
						break;
					while (*++p)
						continue;
				}
			}
			*members = NULL;

			return 0;
		}
	} /* while (1) */

 ERR:
	return -1;
}

/**********************************************************************/

#if ENABLE_USE_BB_SHADOW
static const unsigned char sp_off[] ALIGN1 = {
	offsetof(struct spwd, sp_namp),         /* 0: char* */
	offsetof(struct spwd, sp_pwdp),         /* 1: char* */
	offsetof(struct spwd, sp_lstchg),       /* 2: long */
	offsetof(struct spwd, sp_min),          /* 3: long */
	offsetof(struct spwd, sp_max),          /* 4: long */
	offsetof(struct spwd, sp_warn),         /* 5: long */
	offsetof(struct spwd, sp_inact),        /* 6: long */
	offsetof(struct spwd, sp_expire),       /* 7: long */
	offsetof(struct spwd, sp_flag)          /* 8: unsigned long */
};

static int FAST_FUNC bb__parsespent(void *data, char *line)
{
	char *endptr;
	char *p;
	int i;

	i = 0;
	while (1) {
		p = (char *) data + sp_off[i];
		if (i < 2) {
			*((char **) p) = line;
			line = strchr(line, ':');
			if (!line) {
				break; /* error */
			}
		} else {
			*((long *) p) = strtoul(line, &endptr, 10);
			if (endptr == line) {
				*((long *) p) = -1L;
			}
			line = endptr;
			if (i == 8) {
				if (*line != '\0') {
					break; /* error */
				}
				return 0; /* all ok */
			}
			if (*line != ':') {
				break; /* error */
			}
		}
		*line++ = '\0';
		i++;
	}

	return EINVAL;
}
#endif

/**********************************************************************/

/* Reads until EOF, or until it finds a line which fits in the buffer
 * and for which the parser function succeeds.
 *
 * Returns 0 on success and ENOENT for end-of-file (glibc convention).
 */
static int bb__pgsreader(
		int FAST_FUNC (*parserfunc)(void *d, char *line),
		void *data,
		char *__restrict line_buff,
		size_t buflen,
		FILE *f)
{
	int skip;
	int rv = ERANGE;

	if (buflen < PWD_BUFFER_SIZE) {
		errno = rv;
		return rv;
	}

	skip = 0;
	while (1) {
		if (!fgets(line_buff, buflen, f)) {
			if (feof(f)) {
				rv = ENOENT;
			}
			break;
		}

		{
			int line_len = strlen(line_buff) - 1;
			if (line_len >= 0 && line_buff[line_len] == '\n') {
				line_buff[line_len] = '\0';
			} else
			if (line_len + 2 == buflen) {
				/* A start (or continuation) of overlong line */
				skip = 1;
				continue;
			} /* else: a last line in the file, and it has no '\n' */
		}

		if (skip) {
			/* This "line" is a remainder of overlong line, ignore */
			skip = 0;
			continue;
		}

		/* NOTE: glibc difference - glibc strips leading whitespace from
		 * records.  We do not allow leading whitespace. */

		/* Skip empty lines, comment lines, and lines with leading
		 * whitespace. */
		if (line_buff[0] != '\0' && line_buff[0] != '#' && !isspace(line_buff[0])) {
			if (parserfunc == bb__parsegrent) {
				/* Do evil group hack:
				 * The group entry parsing function needs to know where
				 * the end of the buffer is so that it can construct the
				 * group member ptr table. */
				((struct group *) data)->gr_name = line_buff + buflen;
			}
			if (parserfunc(data, line_buff) == 0) {
				rv = 0;
				break;
			}
		}
	} /* while (1) */

	return rv;
}