.
[glibc/history.git] / grp / initgroups.c
blobcab63e52bfa504848818cf629454f65e522b19c7
1 /* Copyright (C) 1989,91,93,1996-2005,2006,2008 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, write to the Free
16 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
17 02111-1307 USA. */
19 #include <alloca.h>
20 #include <assert.h>
21 #include <errno.h>
22 #include <grp.h>
23 #include <limits.h>
24 #include <stdlib.h>
25 #include <string.h>
26 #include <unistd.h>
27 #include <sys/param.h>
28 #include <sys/types.h>
29 #include <nsswitch.h>
31 #include "../nscd/nscd-client.h"
32 #include "../nscd/nscd_proto.h"
35 /* Type of the lookup function. */
36 typedef enum nss_status (*initgroups_dyn_function) (const char *, gid_t,
37 long int *, long int *,
38 gid_t **, long int, int *);
40 /* The lookup function for the first entry of this service. */
41 extern int __nss_group_lookup (service_user **nip, const char *name,
42 void **fctp);
43 extern void *__nss_lookup_function (service_user *ni, const char *fct_name);
45 extern service_user *__nss_group_database attribute_hidden;
48 #include "compat-initgroups.c"
51 static int
52 internal_getgrouplist (const char *user, gid_t group, long int *size,
53 gid_t **groupsp, long int limit)
55 #ifdef USE_NSCD
56 if (__nss_not_use_nscd_group > 0
57 && ++__nss_not_use_nscd_group > NSS_NSCD_RETRY)
58 __nss_not_use_nscd_group = 0;
59 if (!__nss_not_use_nscd_group)
61 int n = __nscd_getgrouplist (user, group, size, groupsp, limit);
62 if (n >= 0)
63 return n;
65 /* nscd is not usable. */
66 __nss_not_use_nscd_group = 1;
68 #endif
70 service_user *nip = NULL;
71 initgroups_dyn_function fct;
72 enum nss_status status = NSS_STATUS_UNAVAIL;
73 int no_more;
74 /* Start is one, because we have the first group as parameter. */
75 long int start = 1;
77 /* Never store more than the starting *SIZE number of elements. */
78 assert (*size > 0);
79 (*groupsp)[0] = group;
81 if (__nss_group_database != NULL)
83 no_more = 0;
84 nip = __nss_group_database;
86 else
87 no_more = __nss_database_lookup ("group", NULL,
88 "compat [NOTFOUND=return] files", &nip);
90 while (! no_more)
92 long int prev_start = start;
94 fct = __nss_lookup_function (nip, "initgroups_dyn");
96 if (fct == NULL)
97 status = compat_call (nip, user, group, &start, size, groupsp,
98 limit, &errno);
99 else
100 status = DL_CALL_FCT (fct, (user, group, &start, size, groupsp,
101 limit, &errno));
103 /* Remove duplicates. */
104 long int cnt = prev_start;
105 while (cnt < start)
107 long int inner;
108 for (inner = 0; inner < prev_start; ++inner)
109 if ((*groupsp)[inner] == (*groupsp)[cnt])
110 break;
112 if (inner < prev_start)
113 (*groupsp)[cnt] = (*groupsp)[--start];
114 else
115 ++cnt;
118 /* This is really only for debugging. */
119 if (NSS_STATUS_TRYAGAIN > status || status > NSS_STATUS_RETURN)
120 __libc_fatal ("illegal status in internal_getgrouplist");
122 if (status != NSS_STATUS_SUCCESS
123 && nss_next_action (nip, status) == NSS_ACTION_RETURN)
124 break;
126 if (nip->next == NULL)
127 no_more = -1;
128 else
129 nip = nip->next;
132 return start;
135 /* Store at most *NGROUPS members of the group set for USER into
136 *GROUPS. Also include GROUP. The actual number of groups found is
137 returned in *NGROUPS. Return -1 if the if *NGROUPS is too small. */
139 getgrouplist (const char *user, gid_t group, gid_t *groups, int *ngroups)
141 long int size = MAX (1, *ngroups);
143 gid_t *newgroups = (gid_t *) malloc (size * sizeof (gid_t));
144 if (__builtin_expect (newgroups == NULL, 0))
145 /* No more memory. */
146 // XXX This is wrong. The user provided memory, we have to use
147 // XXX it. The internal functions must be called with the user
148 // XXX provided buffer and not try to increase the size if it is
149 // XXX too small. For initgroups a flag could say: increase size.
150 return -1;
152 int total = internal_getgrouplist (user, group, &size, &newgroups, -1);
154 memcpy (groups, newgroups, MIN (*ngroups, total) * sizeof (gid_t));
156 free (newgroups);
158 int retval = total > *ngroups ? -1 : total;
159 *ngroups = total;
161 return retval;
164 static_link_warning (getgrouplist)
166 /* Initialize the group set for the current user
167 by reading the group database and using all groups
168 of which USER is a member. Also include GROUP. */
170 initgroups (const char *user, gid_t group)
172 #if defined NGROUPS_MAX && NGROUPS_MAX == 0
174 /* No extra groups allowed. */
175 return 0;
177 #else
179 long int size;
180 gid_t *groups;
181 int ngroups;
182 int result;
184 /* We always use sysconf even if NGROUPS_MAX is defined. That way, the
185 limit can be raised in the kernel configuration without having to
186 recompile libc. */
187 long int limit = __sysconf (_SC_NGROUPS_MAX);
189 if (limit > 0)
190 /* We limit the size of the intially allocated array. */
191 size = MIN (limit, 64);
192 else
193 /* No fixed limit on groups. Pick a starting buffer size. */
194 size = 16;
196 groups = (gid_t *) malloc (size * sizeof (gid_t));
197 if (__builtin_expect (groups == NULL, 0))
198 /* No more memory. */
199 return -1;
201 ngroups = internal_getgrouplist (user, group, &size, &groups, limit);
203 /* Try to set the maximum number of groups the kernel can handle. */
205 result = setgroups (ngroups, groups);
206 while (result == -1 && errno == EINVAL && --ngroups > 0);
208 free (groups);
210 return result;
211 #endif
214 static_link_warning (initgroups)