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 /* 28 * Default backend-finder(s) for the name-service-switch routines. 29 * At present there is a single finder that uses dlopen() to do its thing. 30 * 31 * === Could also do a finder that includes db-name in filename 32 * === and one that does dlopen(0) to check in the executable 33 */ 34 35 /* Allow our finder(s) to be overridden by user-supplied ones */ 36 37 #pragma weak _nss_default_finders = nss_default_finders 38 39 #include "lint.h" 40 #include "mtlib.h" 41 #include <nss_common.h> 42 #include <dlfcn.h> 43 #include <stdio.h> 44 #include <stdlib.h> 45 #include <string.h> 46 #include <alloca.h> 47 48 /* === ? move these constants to a public header file ? */ 49 static const int dlopen_version = 1; 50 #ifndef NSS_DLOPEN_FORMAT 51 #define NSS_DLOPEN_FORMAT "nss_%s.so.%d" 52 #endif 53 #ifndef NSS_DLSYM_FORMAT 54 #define NSS_DLSYM_FORMAT "_nss_%s_%s_constr" 55 #endif 56 static const char dlopen_format[] = NSS_DLOPEN_FORMAT; 57 static const char dlsym_format [] = NSS_DLSYM_FORMAT; 58 static const size_t format_maxlen = sizeof (dlsym_format) - 4; 59 60 static nss_backend_constr_t 61 SO_per_src_lookup(void *dummy __unused, const char *db_name, 62 const char *src_name, void **delete_privp) 63 { 64 char *name; 65 void *dlhandle; 66 void *sym; 67 size_t len; 68 nss_backend_constr_t res = 0; 69 70 len = format_maxlen + strlen(db_name) + strlen(src_name); 71 name = alloca(len); 72 (void) sprintf(name, dlopen_format, src_name, dlopen_version); 73 if ((dlhandle = dlopen(name, RTLD_LAZY)) != 0) { 74 (void) sprintf(name, dlsym_format, src_name, db_name); 75 if ((sym = dlsym(dlhandle, name)) == 0) { 76 (void) dlclose(dlhandle); 77 } else { 78 *delete_privp = dlhandle; 79 res = (nss_backend_constr_t)sym; 80 } 81 } 82 return (res); 83 } 84 85 static void 86 SO_per_src_delete(void *delete_priv, nss_backend_constr_t dummy __unused) 87 { 88 (void) dlclose(delete_priv); 89 } 90 91 static nss_backend_finder_t SO_per_src = { 92 SO_per_src_lookup, 93 SO_per_src_delete, 94 0, 95 0 96 }; 97 98 nss_backend_finder_t *nss_default_finders = &SO_per_src; 99