1/* Initgroups handling in nss_db module.
2 Copyright (C) 2011-2019 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@gmail.com>.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Library General Public License as
8 published by the Free Software Foundation; either version 2 of the
9 License, or (at your option) any later version.
10
11 The GNU C Library 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 GNU
14 Library General Public License for more details.
15
16 You should have received a copy of the GNU Library General Public
17 License along with the GNU C Library; see the file COPYING.LIB. If
18 not, see <http://www.gnu.org/licenses/>. */
19
20#include <ctype.h>
21#include <errno.h>
22#include <grp.h>
23#include <limits.h>
24#include <paths.h>
25#include <stdlib.h>
26#include <string.h>
27#include <stdint.h>
28#include <sys/param.h>
29
30#include "nss_db.h"
31
32/* The hashing function we use. */
33#include "../intl/hash-string.h"
34
35
36enum nss_status
37_nss_db_initgroups_dyn (const char *user, gid_t group, long int *start,
38 long int *size, gid_t **groupsp, long int limit,
39 int *errnop)
40{
41 struct nss_db_map state = { NULL, 0 };
42 enum nss_status status = internal_setent (_PATH_VARDB "group.db", &state);
43 if (status != NSS_STATUS_SUCCESS)
44 {
45 *errnop = errno;
46 return status;
47 }
48
49 const struct nss_db_header *header = state.header;
50 int i;
51 for (i = 0; i < header->ndbs; ++i)
52 if (header->dbs[i].id == ':')
53 break;
54 if (i == header->ndbs)
55 {
56 status = NSS_STATUS_UNAVAIL;
57 goto out;
58 }
59
60 const stridx_t *hashtable
61 = (const stridx_t *) ((const char *) header
62 + header->dbs[i].hashoffset);
63 const char *valstrtab = (const char *) header + header->valstroffset;
64 size_t userlen = strlen (user);
65 uint32_t hashval = __hash_string (user);
66 size_t hidx = hashval % header->dbs[i].hashsize;
67 size_t hval2 = 1 + hashval % (header->dbs[i].hashsize - 2);
68
69 gid_t *groups = *groupsp;
70
71 status = NSS_STATUS_NOTFOUND;
72 while (hashtable[hidx] != ~((stridx_t) 0))
73 {
74 const char *valstr = valstrtab + hashtable[hidx];
75 while (isblank (*valstr))
76 ++valstr;
77
78 if (strncmp (valstr, user, userlen) == 0 && isblank (valstr[userlen]))
79 {
80 valstr += userlen + 1;
81 while (isblank (*valstr))
82 ++valstr;
83
84 while (*valstr != '\0')
85 {
86 errno = 0;
87 char *endp;
88 unsigned long int n = strtoul (valstr, &endp, 10);
89 if (*endp != ',' && *endp != '\0')
90 break;
91 valstr = *endp == '\0' ? endp : endp + 1;
92
93 if (n != ULONG_MAX || errno != ERANGE)
94 {
95 /* Insert the group. */
96 if (*start == *size)
97 {
98 /* Need a bigger buffer. */
99 if (limit > 0 && *size == limit)
100 {
101 /* We reached the maximum. */
102 status = NSS_STATUS_SUCCESS;
103 goto out;
104 }
105
106 long int newsize;
107 if (limit <= 0)
108 newsize = 2 * *size;
109 else
110 newsize = MIN (limit, 2 * *size);
111
112 gid_t *newgroups = realloc (groups,
113 newsize * sizeof (*groups));
114 if (newgroups == NULL)
115 {
116 *errnop = ENOMEM;
117 status = NSS_STATUS_TRYAGAIN;
118 goto out;
119 }
120
121 *groupsp = groups = newgroups;
122 *size = newsize;
123 }
124
125 groups[*start] = n;
126 *start += 1;
127 }
128 }
129
130 status = NSS_STATUS_SUCCESS;
131 break;
132 }
133
134 if ((hidx += hval2) >= header->dbs[i].hashsize)
135 hidx -= header->dbs[i].hashsize;
136 }
137
138 out:
139 internal_endent (&state);
140
141 return status;
142}
143