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[glibc.git] / grp / initgroups.c
blob06c48bb04058407c413647661741245cab684f70
1 /* Copyright (C) 1989, 91, 93, 1996-1999, 2000 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 Library General Public License as
6 published by the Free Software Foundation; either version 2 of the
7 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 Library General Public License for more details.
14 You should have received a copy of the GNU Library General Public
15 License along with the GNU C Library; see the file COPYING.LIB. If not,
16 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 Boston, MA 02111-1307, USA. */
19 #include <alloca.h>
20 #include <errno.h>
21 #include <grp.h>
22 #include <limits.h>
23 #include <stdlib.h>
24 #include <string.h>
25 #include <unistd.h>
26 #include <sys/types.h>
27 #include <nsswitch.h>
29 /* Type of the lookup function. */
30 typedef enum nss_status (*initgroups_function) (const char *, gid_t,
31 long int *, long int *,
32 gid_t *, long int, int *);
33 /* Prototype for the setgrent functions we use here. */
34 typedef enum nss_status (*set_function) (void);
36 /* Prototype for the endgrent functions we use here. */
37 typedef enum nss_status (*end_function) (void);
39 /* Prototype for the setgrent functions we use here. */
40 typedef enum nss_status (*get_function) (struct group *, char *,
41 size_t, int *);
43 /* The lookup function for the first entry of this service. */
44 extern int __nss_group_lookup (service_user **nip, const char *name,
45 void **fctp);
46 extern void *__nss_lookup_function (service_user *ni, const char *fct_name);
48 extern service_user *__nss_group_database;
50 static enum nss_status
51 compat_call (service_user *nip, const char *user, gid_t group, long int *start,
52 long int *size, gid_t *groups, long int limit, int *errnop)
54 struct group grpbuf;
55 size_t buflen = __sysconf (_SC_GETGR_R_SIZE_MAX);
56 char *tmpbuf;
57 enum nss_status status;
58 set_function setgrent_fct;
59 get_function getgrent_fct;
60 end_function endgrent_fct;
62 getgrent_fct = __nss_lookup_function (nip, "getgrent_r");
63 if (getgrent_fct == NULL)
64 return NSS_STATUS_UNAVAIL;
66 setgrent_fct = __nss_lookup_function (nip, "setgrent");
67 if (setgrent_fct)
69 status = DL_CALL_FCT (setgrent_fct, ());
70 if (status != NSS_STATUS_SUCCESS)
71 return status;
74 endgrent_fct = __nss_lookup_function (nip, "endgrent");
76 tmpbuf = __alloca (buflen);
80 while ((status = DL_CALL_FCT (getgrent_fct,
81 (&grpbuf, tmpbuf, buflen, errnop)),
82 status == NSS_STATUS_TRYAGAIN)
83 && *errnop == ERANGE)
85 buflen *= 2;
86 tmpbuf = __alloca (buflen);
89 if (status != NSS_STATUS_SUCCESS)
90 goto done;
92 if (grpbuf.gr_gid != group)
94 char **m;
96 for (m = grpbuf.gr_mem; *m != NULL; ++m)
97 if (strcmp (*m, user) == 0)
99 /* Matches user. Insert this group. */
100 if (*start == *size && limit <= 0)
102 /* Need a bigger buffer. */
103 groups = realloc (groups, 2 * *size * sizeof (*groups));
104 if (groups == NULL)
105 goto done;
106 *size *= 2;
109 groups[*start] = grpbuf.gr_gid;
110 *start += 1;
112 if (*start == limit)
113 /* Can't take any more groups; stop searching. */
114 goto done;
116 break;
120 while (status == NSS_STATUS_SUCCESS);
122 done:
123 if (endgrent_fct)
124 DL_CALL_FCT (endgrent_fct, ());
126 return NSS_STATUS_SUCCESS;
129 /* Initialize the group set for the current user
130 by reading the group database and using all groups
131 of which USER is a member. Also include GROUP. */
133 initgroups (user, group)
134 const char *user;
135 gid_t group;
137 #if defined NGROUPS_MAX && NGROUPS_MAX == 0
139 /* No extra groups allowed. */
140 return 0;
142 #else
144 service_user *nip = NULL;
145 initgroups_function fct;
146 enum nss_status status = NSS_STATUS_UNAVAIL;
147 int no_more;
148 /* Start is one, because we have the first group as parameter. */
149 long int start = 1;
150 long int size;
151 gid_t *groups;
152 #ifdef NGROUPS_MAX
153 # define limit NGROUPS_MAX
155 size = limit;
156 #else
157 long int limit = __sysconf (_SC_NGROUPS_MAX);
159 if (limit > 0)
160 size = limit;
161 else
162 /* No fixed limit on groups. Pick a starting buffer size. */
163 size = 16;
164 #endif
166 groups = (gid_t *) malloc (size * sizeof (gid_t));
167 if (__builtin_expect (groups == NULL, 0))
168 /* No more memory. */
169 return -1;
171 groups[0] = group;
173 if (__nss_group_database != NULL)
175 no_more = 0;
176 nip = __nss_group_database;
178 else
179 no_more = __nss_database_lookup ("group", NULL,
180 "compat [NOTFOUND=return] files", &nip);
182 while (! no_more)
184 fct = __nss_lookup_function (nip, "initgroups");
186 if (fct == NULL)
188 status = compat_call (nip, user, group, &start, &size, groups,
189 limit, &errno);
191 if (nss_next_action (nip, NSS_STATUS_UNAVAIL) != NSS_ACTION_CONTINUE)
192 break;
194 else
195 status = DL_CALL_FCT (fct, (user, group, &start, &size, groups, limit,
196 &errno));
198 /* This is really only for debugging. */
199 if (NSS_STATUS_TRYAGAIN > status || status > NSS_STATUS_RETURN)
200 __libc_fatal ("illegal status in " __FUNCTION__);
202 if (status != NSS_STATUS_SUCCESS
203 && nss_next_action (nip, status) == NSS_ACTION_RETURN)
204 break;
206 if (nip->next == NULL)
207 no_more = -1;
208 else
209 nip = nip->next;
212 return setgroups (start, groups);
213 #endif