1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 #pragma ident "%Z%%M% %I% %E% SMI"
28
29 /*
30 * Default backend-finder(s) for the name-service-switch routines.
31 * At present there is a single finder that uses dlopen() to do its thing.
32 *
33 * === Could also do a finder that includes db-name in filename
34 * === and one that does dlopen(0) to check in the executable
35 */
36
37 /* Allow our finder(s) to be overridden by user-supplied ones */
38
39 #pragma weak _nss_default_finders = nss_default_finders
40
41 #include "lint.h"
42 #include "mtlib.h"
43 #include <nss_common.h>
44 #include <dlfcn.h>
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <string.h>
48 #include <alloca.h>
49
50 /* === ? move these constants to a public header file ? */
51 static const int dlopen_version = 1;
52 #ifndef NSS_DLOPEN_FORMAT
53 #define NSS_DLOPEN_FORMAT "nss_%s.so.%d"
54 #endif
55 #ifndef NSS_DLSYM_FORMAT
56 #define NSS_DLSYM_FORMAT "_nss_%s_%s_constr"
57 #endif
58 static const char dlopen_format[] = NSS_DLOPEN_FORMAT;
59 static const char dlsym_format [] = NSS_DLSYM_FORMAT;
60 static const size_t format_maxlen = sizeof (dlsym_format) - 4;
61
62 /*ARGSUSED*/
63 static nss_backend_constr_t
SO_per_src_lookup(void * dummy,const char * db_name,const char * src_name,void ** delete_privp)64 SO_per_src_lookup(void *dummy, const char *db_name, const char *src_name,
65 void **delete_privp)
66 {
67 char *name;
68 void *dlhandle;
69 void *sym;
70 size_t len;
71 nss_backend_constr_t res = 0;
72
73 len = format_maxlen + strlen(db_name) + strlen(src_name);
74 name = alloca(len);
75 (void) sprintf(name, dlopen_format, src_name, dlopen_version);
76 if ((dlhandle = dlopen(name, RTLD_LAZY)) != 0) {
77 (void) sprintf(name, dlsym_format, src_name, db_name);
78 if ((sym = dlsym(dlhandle, name)) == 0) {
79 (void) dlclose(dlhandle);
80 } else {
81 *delete_privp = dlhandle;
82 res = (nss_backend_constr_t)sym;
83 }
84 }
85 return (res);
86 }
87
88 /*ARGSUSED*/
89 static void
SO_per_src_delete(void * delete_priv,nss_backend_constr_t dummy)90 SO_per_src_delete(void *delete_priv, nss_backend_constr_t dummy)
91 {
92 (void) dlclose(delete_priv);
93 }
94
95 static nss_backend_finder_t SO_per_src = {
96 SO_per_src_lookup,
97 SO_per_src_delete,
98 0,
99 0
100 };
101
102 nss_backend_finder_t *nss_default_finders = &SO_per_src;
103