1/* Initgroups handling in nss_db module.
2 Copyright (C) 2011-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public License as
7 published by the Free Software Foundation; either version 2 of the
8 License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
14
15 You should have received a copy of the GNU Library General Public
16 License along with the GNU C Library; see the file COPYING.LIB. If
17 not, see <https://www.gnu.org/licenses/>. */
18
19#include <ctype.h>
20#include <errno.h>
21#include <grp.h>
22#include <limits.h>
23#include <paths.h>
24#include <stdlib.h>
25#include <string.h>
26#include <stdint.h>
27#include <sys/param.h>
28
29#include "nss_db.h"
30
31/* The hashing function we use. */
32#include "../intl/hash-string.h"
33
34enum nss_status
35_nss_db_initgroups_dyn (const char *user, gid_t group, long int *start,
36 long int *size, gid_t **groupsp, long int limit,
37 int *errnop)
38{
39 struct nss_db_map state = { NULL, 0 };
40 enum nss_status status = internal_setent (_PATH_VARDB "group.db", &state);
41 if (status != NSS_STATUS_SUCCESS)
42 {
43 *errnop = errno;
44 return status;
45 }
46
47 const struct nss_db_header *header = state.header;
48 int i;
49 for (i = 0; i < header->ndbs; ++i)
50 if (header->dbs[i].id == ':')
51 break;
52 if (i == header->ndbs)
53 {
54 status = NSS_STATUS_UNAVAIL;
55 goto out;
56 }
57
58 const stridx_t *hashtable
59 = (const stridx_t *) ((const char *) header
60 + header->dbs[i].hashoffset);
61 const char *valstrtab = (const char *) header + header->valstroffset;
62 size_t userlen = strlen (user);
63 uint32_t hashval = __hash_string (user);
64 size_t hidx = hashval % header->dbs[i].hashsize;
65 size_t hval2 = 1 + hashval % (header->dbs[i].hashsize - 2);
66
67 gid_t *groups = *groupsp;
68
69 status = NSS_STATUS_NOTFOUND;
70 while (hashtable[hidx] != ~((stridx_t) 0))
71 {
72 const char *valstr = valstrtab + hashtable[hidx];
73 while (isblank (*valstr))
74 ++valstr;
75
76 if (strncmp (valstr, user, userlen) == 0 && isblank (valstr[userlen]))
77 {
78 valstr += userlen + 1;
79 while (isblank (*valstr))
80 ++valstr;
81
82 while (*valstr != '\0')
83 {
84 errno = 0;
85 char *endp;
86 unsigned long int n = strtoul (valstr, &endp, 10);
87 if (*endp != ',' && *endp != '\0')
88 break;
89 valstr = *endp == '\0' ? endp : endp + 1;
90
91 if (n != ULONG_MAX || errno != ERANGE)
92 {
93 /* Insert the group. */
94 if (*start == *size)
95 {
96 /* Need a bigger buffer. */
97 if (limit > 0 && *size == limit)
98 {
99 /* We reached the maximum. */
100 status = NSS_STATUS_SUCCESS;
101 goto out;
102 }
103
104 long int newsize;
105 if (limit <= 0)
106 newsize = 2 * *size;
107 else
108 newsize = MIN (limit, 2 * *size);
109
110 gid_t *newgroups = realloc (groups,
111 newsize * sizeof (*groups));
112 if (newgroups == NULL)
113 {
114 *errnop = ENOMEM;
115 status = NSS_STATUS_TRYAGAIN;
116 goto out;
117 }
118
119 *groupsp = groups = newgroups;
120 *size = newsize;
121 }
122
123 groups[*start] = n;
124 *start += 1;
125 }
126 }
127
128 status = NSS_STATUS_SUCCESS;
129 break;
130 }
131
132 if ((hidx += hval2) >= header->dbs[i].hashsize)
133 hidx -= header->dbs[i].hashsize;
134 }
135
136 out:
137 internal_endent (&state);
138
139 return status;
140}
141