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 2006 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 #include <door.h>
28 #include <errno.h>
29 #include <fcntl.h>
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <synch.h>
33 #include <time.h>
34 #include <unistd.h>
35
36 #include <sys/param.h>
37 #include <sys/stat.h>
38 #include <sys/types.h>
39
40 #include "labeld.h"
41
42 #ifndef DEBUG
43 #define perror(e)
44 #endif /* !DEBUG */
45
46 /*
47 * This is cloned from _nsc_trydoorcall used by the nscd client.
48 *
49 * Routine that actually performs the door call.
50 * Note that we cache a file descriptor. We do
51 * the following to prevent disasters:
52 *
53 * 1) Never use 0, 1 or 2; if we get this from the open
54 * we dup it upwards.
55 *
56 * 2) Set the close on exec flags so descriptor remains available
57 * to child processes.
58 *
59 * 3) Verify that the door is still the same one we had before
60 * by using door_info on the client side.
61 *
62 * Note that we never close the file descriptor if it isn't one
63 * we allocated; we check this with door info. The rather tricky
64 * logic is designed to be fast in the normal case (fd is already
65 * allocated and is ok) while handling the case where the application
66 * closed it underneath us or where the nscd dies or re-execs itself
67 * and we're a multi-threaded application. Note that we cannot protect
68 * the application if it closes the fd and it is multi-threaded.
69 *
70 * int __call_labeld(label_door_op **dptr, int *ndata, int *adata);
71 *
72 * *dptr IN: points to arg buffer OUT: points to results buffer
73 * *ndata IN: overall size of buffer OUT: overall size of buffer
74 * *adata IN: size of call data OUT: size of return data
75 *
76 * Note that *dptr may change if provided space as defined by *bufsize is
77 * inadequate. In this case the door call mmaps more space and places
78 * the answer there and sets dptr to contain a pointer to the space, which
79 * should be freed with munmap.
80 *
81 * Returns 0 if the door call reached the server, -1 if contact was not made.
82 *
83 */
84
85
86 static mutex_t _door_lock = DEFAULTMUTEX;
87
88 int
__call_labeld(labeld_data_t ** dptr,size_t * ndata,size_t * adata)89 __call_labeld(labeld_data_t **dptr, size_t *ndata, size_t *adata)
90 {
91 static int doorfd = -1;
92 static door_info_t real_door;
93 struct stat st;
94 door_info_t my_door;
95 door_arg_t param;
96 char door_name[MAXPATHLEN];
97 struct timespec ts;
98 int busy = 0; /* number of busy loops */
99
100 #ifdef DEBUG
101 labeld_data_t *callptr = *dptr;
102 int buf_size = *ndata;
103 int return_size = *adata;
104 #endif /* DEBUG */
105
106 /*
107 * the first time in we try and open and validate the door.
108 * the validations are that the door must have been
109 * created with the label service door cookie and
110 * that it has the same door ID. If any of these
111 * validations fail we refuse to use the door.
112 */
113 ts.tv_sec = 0; /* initialize nanosecond retry timer */
114 ts.tv_nsec = 100;
115 (void) mutex_lock(&_door_lock);
116
117 try_again:
118 if (doorfd == -1) {
119 int tbc[3];
120 int i;
121
122 (void) snprintf(door_name, sizeof (door_name), "%s%s",
123 DOOR_PATH, DOOR_NAME);
124 if ((doorfd = open64(door_name, O_RDONLY, 0)) < 0) {
125 (void) mutex_unlock(&_door_lock);
126 perror("server door open");
127 return (NOSERVER);
128 }
129
130 /*
131 * dup up the file descriptor if we have 0 - 2
132 * to avoid problems with shells stdin/out/err
133 */
134 i = 0;
135 while (doorfd < 3) { /* we have a reserved fd */
136 tbc[i++] = doorfd;
137 if ((doorfd = dup(doorfd)) < 0) {
138 perror("couldn't dup");
139 while (i--)
140 (void) close(tbc[i]);
141 doorfd = -1;
142 (void) mutex_unlock(&_door_lock);
143 return (NOSERVER);
144 }
145 }
146 while (i--)
147 (void) close(tbc[i]);
148
149 /*
150 * mark this door descriptor as close on exec
151 */
152 (void) fcntl(doorfd, F_SETFD, FD_CLOEXEC);
153 if (door_info(doorfd, &real_door) < 0) {
154 /*
155 * we should close doorfd because we just opened it
156 */
157 perror("real door door_info");
158 (void) close(doorfd);
159 doorfd = -1;
160 (void) mutex_unlock(&_door_lock);
161 return (NOSERVER);
162 }
163 if (fstat(doorfd, &st) < 0) {
164 perror("real door fstat");
165 return (NOSERVER);
166 }
167 #ifdef DEBUG
168 (void) printf("\treal door %s\n", door_name);
169 (void) printf("\t\tuid = %d, gid = %d, mode = %o\n", st.st_uid,
170 st.st_gid, st.st_mode);
171 (void) printf("\t\toutstanding requests = %d\n", st.st_nlink-1);
172 (void) printf("\t\t pid = %d\n", real_door.di_target);
173 (void) printf("\t\t procedure = %llx\n", real_door.di_proc);
174 (void) printf("\t\t cookie = %llx\n", real_door.di_data);
175 (void) printf("\t\t attributes = %x\n",
176 real_door.di_attributes);
177 if (real_door.di_attributes & DOOR_UNREF)
178 (void) printf("\t\t\t UNREF\n");
179 if (real_door.di_attributes & DOOR_PRIVATE)
180 (void) printf("\t\t\t PRIVATE\n");
181 if (real_door.di_attributes & DOOR_LOCAL)
182 (void) printf("\t\t\t LOCAL\n");
183 if (real_door.di_attributes & DOOR_REVOKED)
184 (void) printf("\t\t\t REVOKED\n");
185 if (real_door.di_attributes & DOOR_DESCRIPTOR)
186 (void) printf("\t\t\t DESCRIPTOR\n");
187 if (real_door.di_attributes & DOOR_RELEASE)
188 (void) printf("\t\t\t RELEASE\n");
189 if (real_door.di_attributes & DOOR_DELAY)
190 (void) printf("\t\t\t DELAY\n");
191 (void) printf("\t\t id = %llx\n", real_door.di_uniquifier);
192 #endif /* DEBUG */
193 if ((real_door.di_attributes & DOOR_REVOKED) ||
194 (real_door.di_data != COOKIE)) {
195 #ifdef DEBUG
196 (void) printf("real door revoked\n");
197 #endif /* DEBUG */
198 (void) close(doorfd);
199 doorfd = -1;
200 (void) mutex_unlock(&_door_lock);
201 return (NOSERVER);
202 }
203 } else {
204 if ((door_info(doorfd, &my_door) < 0) ||
205 (my_door.di_data != COOKIE) ||
206 (my_door.di_uniquifier != real_door.di_uniquifier)) {
207 perror("my door door_info");
208 /*
209 * don't close it - someone else has clobbered fd
210 */
211 doorfd = -1;
212 goto try_again;
213 }
214 if (fstat(doorfd, &st) < 0) {
215 perror("my door fstat");
216 goto try_again;
217 }
218 #ifdef DEBUG
219 (void) sprintf(door_name, "%s%s", DOOR_PATH, DOOR_NAME);
220 (void) printf("\tmy door %s\n", door_name);
221 (void) printf("\t\tuid = %d, gid = %d, mode = %o\n", st.st_uid,
222 st.st_gid, st.st_mode);
223 (void) printf("\t\toutstanding requests = %d\n", st.st_nlink-1);
224 (void) printf("\t\t pid = %d\n", my_door.di_target);
225 (void) printf("\t\t procedure = %llx\n", my_door.di_proc);
226 (void) printf("\t\t cookie = %llx\n", my_door.di_data);
227 (void) printf("\t\t attributes = %x\n", my_door.di_attributes);
228 if (my_door.di_attributes & DOOR_UNREF)
229 (void) printf("\t\t\t UNREF\n");
230 if (my_door.di_attributes & DOOR_PRIVATE)
231 (void) printf("\t\t\t PRIVATE\n");
232 if (my_door.di_attributes & DOOR_LOCAL)
233 (void) printf("\t\t\t LOCAL\n");
234 if (my_door.di_attributes & DOOR_REVOKED)
235 (void) printf("\t\t\t REVOKED\n");
236 if (my_door.di_attributes & DOOR_DESCRIPTOR)
237 (void) printf("\t\t\t DESCRIPTOR\n");
238 if (my_door.di_attributes & DOOR_RELEASE)
239 (void) printf("\t\t\t RELEASE\n");
240 if (my_door.di_attributes & DOOR_DELAY)
241 (void) printf("\t\t\t DELAY\n");
242 (void) printf("\t\t id = %llx\n", my_door.di_uniquifier);
243 #endif /* DEBUG */
244 if (my_door.di_attributes & DOOR_REVOKED) {
245 #ifdef DEBUG
246 (void) printf("my door revoked\n");
247 #endif /* DEBUG */
248 (void) close(doorfd); /* labeld exited .... */
249 doorfd = -1; /* try and restart connection */
250 goto try_again;
251 }
252 }
253 (void) mutex_unlock(&_door_lock);
254
255 param.data_ptr = (char *)*dptr;
256 param.data_size = *adata;
257 param.desc_ptr = NULL;
258 param.desc_num = 0;
259 param.rbuf = (char *)*dptr;
260 param.rsize = *ndata;
261
262 if (door_call(doorfd, ¶m) < 0) {
263 if (errno == EAGAIN && busy++ < 10) {
264 /* adjust backoff */
265 if ((ts.tv_nsec *= 10) >= NANOSEC) {
266 ts.tv_sec++;
267 ts.tv_nsec = 100;
268 }
269 (void) nanosleep(&ts, NULL);
270 #ifdef DEBUG
271 (void) printf("door_call failed EAGAIN # %d\n", busy);
272 #endif /* DEBUG */
273 (void) mutex_lock(&_door_lock);
274 goto try_again;
275 }
276 perror("door call");
277 return (NOSERVER);
278 }
279
280 *adata = (int)param.data_size;
281 *ndata = (int)param.rsize;
282 /*LINTED*/
283 *dptr = (labeld_data_t *)param.data_ptr;
284
285 if (*adata == 0 || *dptr == NULL) {
286 #ifdef DEBUG
287 (void) printf("\tNo data returned, size = %lu, dptr = %p\n",
288 (unsigned long)*adata, (void *)*dptr);
289 #endif /* DEBUG */
290 return (NOSERVER);
291 }
292 #ifdef DEBUG
293 (void) printf("call buf = %x, buf size = %d, call size = %d\n",
294 callptr, buf_size, return_size);
295 (void) printf("retn buf = %x, buf size = %d, retn size = %d\n",
296 *dptr, *ndata, *adata);
297 (void) printf("\treply status = %d\n", (*dptr)->param.aret.ret);
298 #endif /* DEBUG */
299 return ((*dptr)->param.aret.ret);
300
301 } /* __call_labeld */
302