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[glibc.git] / grp / initgroups.c
blobb7708077b60deb7ab456cb1c72061163501820d9
1 /* Copyright (C) 1989, 91, 93, 96, 97, 98 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>
30 /* Type of the lookup function. */
31 typedef enum nss_status (*initgroups_function) (const char *, gid_t,
32 long int *, long int *,
33 gid_t *, long int, int *);
34 /* Prototype for the setgrent functions we use here. */
35 typedef enum nss_status (*set_function) (void);
37 /* Prototype for the endgrent functions we use here. */
38 typedef enum nss_status (*end_function) (void);
40 /* Prototype for the setgrent functions we use here. */
41 typedef enum nss_status (*get_function) (struct group *, char *,
42 size_t, int *);
44 /* The lookup function for the first entry of this service. */
45 extern int __nss_group_lookup (service_user **nip, const char *name,
46 void **fctp);
47 extern void *__nss_lookup_function (service_user *ni, const char *fct_name);
49 extern service_user *__nss_group_database;
51 static enum nss_status
52 compat_call (service_user *nip, const char *user, gid_t group, long int *start,
53 long int *size, gid_t *groups, long int limit, int *errnop)
55 struct group grpbuf, *g;
56 size_t buflen = __sysconf (_SC_GETPW_R_SIZE_MAX);
57 char *tmpbuf;
58 enum nss_status status;
59 set_function setgrent_fct;
60 get_function getgrent_fct;
61 end_function endgrent_fct;
63 getgrent_fct = __nss_lookup_function (nip, "getgrent_r");
64 if (getgrent_fct == NULL)
65 return NSS_STATUS_UNAVAIL;
67 setgrent_fct = __nss_lookup_function (nip, "setgrent");
68 if (setgrent_fct)
70 status = _CALL_DL_FCT (setgrent_fct, ());
71 if (status != NSS_STATUS_SUCCESS)
72 return status;
75 endgrent_fct = __nss_lookup_function (nip, "endgrent");
77 tmpbuf = __alloca (buflen);
81 while ((status = _CALL_DL_FCT (getgrent_fct,
82 (&grpbuf, tmpbuf, buflen, errnop)),
83 status == NSS_STATUS_TRYAGAIN)
84 && *errnop == ERANGE)
86 buflen *= 2;
87 tmpbuf = __alloca (buflen);
90 if (status != NSS_STATUS_SUCCESS)
91 goto done;
93 g = &grpbuf;
94 if (g->gr_gid != group)
96 char **m;
98 for (m = g->gr_mem; *m != NULL; ++m)
99 if (strcmp (*m, user) == 0)
101 /* Matches user. Insert this group. */
102 if (*start == *size && limit <= 0)
104 /* Need a bigger buffer. */
105 groups = realloc (groups, *size * sizeof (*groups));
106 if (groups == NULL)
107 goto done;
108 *size *= 2;
111 groups[*start] = g->gr_gid;
112 *start += 1;
114 if (*start == limit)
115 /* Can't take any more groups; stop searching. */
116 goto done;
118 break;
122 while (status == NSS_STATUS_SUCCESS);
124 done:
125 if (endgrent_fct)
126 _CALL_DL_FCT (endgrent_fct, ());
128 return NSS_STATUS_SUCCESS;
131 /* Initialize the group set for the current user
132 by reading the group database and using all groups
133 of which USER is a member. Also include GROUP. */
135 initgroups (user, group)
136 const char *user;
137 gid_t group;
139 #if defined NGROUPS_MAX && NGROUPS_MAX == 0
141 /* No extra groups allowed. */
142 return 0;
144 #else
146 service_user *nip = NULL;
147 initgroups_function fct;
148 enum nss_status status = NSS_STATUS_UNAVAIL;
149 int no_more;
150 /* Start is one, because we have the first group as parameter. */
151 long int start = 1;
152 long int size;
153 gid_t *groups;
154 #ifdef NGROUPS_MAX
155 # define limit NGROUPS_MAX
157 size = limit;
158 #else
159 long int limit = __sysconf (_SC_NGROUPS_MAX);
161 if (limit > 0)
162 size = limit;
163 else
164 /* No fixed limit on groups. Pick a starting buffer size. */
165 size = 16;
166 #endif
168 groups = malloc (size * sizeof (gid_t *));
170 groups[0] = group;
172 if (__nss_group_database != NULL)
174 no_more = 0;
175 nip = __nss_group_database;
177 else
178 no_more = __nss_database_lookup ("group", NULL,
179 "compat [NOTFOUND=return] files", &nip);
181 while (! no_more)
183 fct = __nss_lookup_function (nip, "initgroups");
185 if (fct == NULL)
187 status = compat_call (nip, user, group, &start, &size, groups,
188 limit, &errno);
190 if (nss_next_action (nip, NSS_STATUS_UNAVAIL) != NSS_ACTION_CONTINUE)
191 break;
193 else
194 status = _CALL_DL_FCT (fct, (user, group, &start, &size, groups, limit,
195 &errno));
197 /* This is really only for debugging. */
198 if (NSS_STATUS_TRYAGAIN > status || status > NSS_STATUS_RETURN)
199 __libc_fatal ("illegal status in " __FUNCTION__);
201 if (nss_next_action (nip, status) == NSS_ACTION_RETURN)
202 break;
204 if (nip->next == NULL)
205 no_more = -1;
206 else
207 nip = nip->next;
210 return setgroups (start, groups);
211 #endif