1 /*
2  * lib/kdb/kdb_ldap/ldap_handle.c
3  *
4  * Copyright (c) 2004-2005, Novell, Inc.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions are met:
9  *
10  *   * Redistributions of source code must retain the above copyright notice,
11  *       this list of conditions and the following disclaimer.
12  *   * Redistributions in binary form must reproduce the above copyright
13  *       notice, this list of conditions and the following disclaimer in the
14  *       documentation and/or other materials provided with the distribution.
15  *   * The copyright holder's name is not used to endorse or promote products
16  *       derived from this software without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
19  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
22  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28  * POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 #include "ldap_main.h"
32 
33 
34 #ifdef ASYNC_BIND
35 
36 /*
37  * Update the server info structure. In case of an asynchronous bind,
38  * this function is called to check the bind status. A flag
39  * server_info_upate_pending is refered before calling this function.
40  * This function sets the server_status to either ON or OFF and
41  * sets the server_info_udpate_pending to OFF.
42  * Do not lock the mutex here. The caller should lock it
43  */
44 
45 static krb5_error_code
krb5_update_server_info(ldap_server_handle,server_info)46 krb5_update_server_info(ldap_server_handle, server_info)
47     krb5_ldap_server_handle    *ldap_server_handle;
48     krb5_ldap_server_info      *server_info;
49 {
50     krb5_error_code            st=0;
51     struct timeval             ztime={0, 0};
52     LDAPMessage                *result=NULL;
53 
54     if (ldap_server_handle == NULL || server_info == NULL)
55 	return -1;
56 
57     while (st == 0) {
58 	st = ldap_result(ldap_server_handle->ldap_handle, ldap_server_handle->msgid,
59 			 LDAP_MSG_ALL, &ztime, &result);
60 	switch (st) {
61 	case -1:
62 	    server_info->server_status = OFF;
63 	    time(&server_info->downtime);
64 	    break;
65 
66 	case 0:
67 	    continue;
68 	    break;
69 
70 	case LDAP_RES_BIND:
71 	    if ((st=ldap_result2error(ldap_server_handle->ldap_handle, result, 1)) == LDAP_SUCCESS) {
72 		server_info->server_status = ON;
73 	    } else {
74 		/* ?? */	krb5_set_error_message(0, 0, "%s", ldap_err2string(st));
75 		server_info->server_status = OFF;
76 		time(&server_info->downtime);
77 	    }
78 	    ldap_msgfree(result);
79 	    break;
80 	default:
81 	    ldap_msgfree(result);
82 	    continue;
83 	    break;
84 	}
85     }
86     ldap_server_handle->server_info_update_pending = FALSE;
87     return 0;
88 }
89 #endif
90 
91 /*
92  * Return ldap server handle from the pool. If the pool is exhausted return NULL.
93  * Do not lock the mutex, caller should lock it
94  */
95 
96 static krb5_ldap_server_handle *
krb5_get_ldap_handle(ldap_context)97 krb5_get_ldap_handle(ldap_context)
98     krb5_ldap_context          *ldap_context;
99 {
100     krb5_ldap_server_handle    *ldap_server_handle=NULL;
101     krb5_ldap_server_info      *ldap_server_info=NULL;
102     int                        cnt=0;
103 
104     while (ldap_context->server_info_list[cnt] != NULL) {
105 	ldap_server_info = ldap_context->server_info_list[cnt];
106 	if (ldap_server_info->server_status != OFF) {
107 	    if (ldap_server_info->ldap_server_handles != NULL) {
108 		ldap_server_handle = ldap_server_info->ldap_server_handles;
109 		ldap_server_info->ldap_server_handles = ldap_server_handle->next;
110 		break;
111 #ifdef ASYNC_BIND
112 		if (ldap_server_handle->server_info_update_pending == TRUE) {
113 		    krb5_update_server_info(context, ldap_server_handle,
114 					    ldap_server_info);
115 		}
116 
117 		if (ldap_server_info->server_status == ON) {
118 		    ldap_server_info->ldap_server_handles = ldap_server_handle->next;
119 		    break;
120 		} else
121 		    ldap_server_handle = NULL;
122 #endif
123 	    }
124 	}
125 	++cnt;
126     }
127     return ldap_server_handle;
128 }
129 
130 /*
131  * This is called incase krb5_get_ldap_handle returns NULL.
132  * Try getting a single connection (handle) and return the same by
133  * calling krb5_get_ldap_handle function.
134  * Do not lock the mutex here. The caller should lock it
135  */
136 
137 static krb5_ldap_server_handle *
krb5_retry_get_ldap_handle(ldap_context,st)138 krb5_retry_get_ldap_handle(ldap_context, st)
139     krb5_ldap_context          *ldap_context;
140     krb5_error_code            *st;
141 {
142     krb5_ldap_server_handle    *ldap_server_handle=NULL;
143 
144     if ((*st=krb5_ldap_db_single_init(ldap_context)) != 0)
145 	return NULL;
146 
147     ldap_server_handle = krb5_get_ldap_handle(ldap_context);
148     return ldap_server_handle;
149 }
150 
151 /*
152  * Put back the ldap server handle to the front of the list of handles of the
153  * ldap server info structure.
154  * Do not lock the mutex here. The caller should lock it.
155  */
156 
157 static krb5_error_code
krb5_put_ldap_handle(ldap_server_handle)158 krb5_put_ldap_handle(ldap_server_handle)
159     krb5_ldap_server_handle    *ldap_server_handle;
160 {
161 
162     if (ldap_server_handle == NULL)
163 	return 0;
164 
165     ldap_server_handle->next = ldap_server_handle->server_info->ldap_server_handles;
166     ldap_server_handle->server_info->ldap_server_handles = ldap_server_handle;
167     return 0;
168 }
169 
170 /*
171  * Add a new ldap server handle structure to the server info structure.
172  * This function name can be changed to krb5_insert_ldap_handle.
173  * Do not lock the mutex here. The caller should lock it
174  */
175 
176 krb5_error_code
krb5_update_ldap_handle(ldap_server_handle,server_info)177 krb5_update_ldap_handle(ldap_server_handle, server_info)
178     krb5_ldap_server_handle    *ldap_server_handle;
179     krb5_ldap_server_info      *server_info;
180 {
181 
182     if (ldap_server_handle == NULL || server_info == NULL)
183 	return 0;
184 
185     ldap_server_handle->next = server_info->ldap_server_handles;
186     server_info->ldap_server_handles = ldap_server_handle;
187     server_info->num_conns++;
188     ldap_server_handle->server_info = server_info;
189     return 0;
190 }
191 
192 /*
193  * Free up all the ldap server handles of the server info.
194  * This function is called when the ldap server returns LDAP_SERVER_DOWN.
195  */
196 
197 static krb5_error_code
krb5_ldap_cleanup_handles(ldap_server_info)198 krb5_ldap_cleanup_handles(ldap_server_info)
199     krb5_ldap_server_info      *ldap_server_info;
200 {
201     krb5_ldap_server_handle    *ldap_server_handle = NULL;
202 
203     while (ldap_server_info->ldap_server_handles != NULL) {
204 	ldap_server_handle = ldap_server_info->ldap_server_handles;
205 	ldap_server_info->ldap_server_handles = ldap_server_handle->next;
206 	/* Solaris kerberos: don't leak ldap handles */
207 	ldap_unbind_s(ldap_server_handle->ldap_handle);
208 	free (ldap_server_handle);
209 	ldap_server_handle = NULL;
210     }
211     return 0;
212 }
213 
214 /*
215  * wrapper function called from outside to get a handle.
216  */
217 
218 krb5_error_code
krb5_ldap_request_handle_from_pool(ldap_context,ldap_server_handle)219 krb5_ldap_request_handle_from_pool(ldap_context, ldap_server_handle)
220     krb5_ldap_context          *ldap_context;
221     krb5_ldap_server_handle    **ldap_server_handle;
222 {
223     krb5_error_code            st=0;
224 
225     *ldap_server_handle = NULL;
226 
227     HNDL_LOCK(ldap_context);
228     if (((*ldap_server_handle)=krb5_get_ldap_handle(ldap_context)) == NULL)
229 	(*ldap_server_handle)=krb5_retry_get_ldap_handle(ldap_context, &st);
230     HNDL_UNLOCK(ldap_context);
231     return st;
232 }
233 
234 /*
235  * wrapper function wrapper called to get the next ldap server handle, when the current
236  * ldap server handle returns LDAP_SERVER_DOWN.
237  */
238 
239 krb5_error_code
krb5_ldap_request_next_handle_from_pool(ldap_context,ldap_server_handle)240 krb5_ldap_request_next_handle_from_pool(ldap_context, ldap_server_handle)
241     krb5_ldap_context          *ldap_context;
242     krb5_ldap_server_handle    **ldap_server_handle;
243 {
244     krb5_error_code            st=0;
245 
246     HNDL_LOCK(ldap_context);
247     (*ldap_server_handle)->server_info->server_status = OFF;
248     time(&(*ldap_server_handle)->server_info->downtime);
249     krb5_put_ldap_handle(*ldap_server_handle);
250     krb5_ldap_cleanup_handles((*ldap_server_handle)->server_info);
251 
252     if (((*ldap_server_handle)=krb5_get_ldap_handle(ldap_context)) == NULL)
253 	(*ldap_server_handle)=krb5_retry_get_ldap_handle(ldap_context, &st);
254     HNDL_UNLOCK(ldap_context);
255     return st;
256 }
257 
258 /*
259  * wrapper function to call krb5_put_ldap_handle.
260  */
261 
262 void
krb5_ldap_put_handle_to_pool(ldap_context,ldap_server_handle)263 krb5_ldap_put_handle_to_pool(ldap_context, ldap_server_handle)
264     krb5_ldap_context          *ldap_context;
265     krb5_ldap_server_handle    *ldap_server_handle;
266 {
267 
268     if (ldap_server_handle != NULL) {
269 	HNDL_LOCK(ldap_context);
270 	krb5_put_ldap_handle(ldap_server_handle);
271 	HNDL_UNLOCK(ldap_context);
272     }
273     return;
274 }
275 
276