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, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22 /*
23 * Copyright 2005 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 #include <stdio.h>
28 #include <fcntl.h>
29 #include <errno.h>
30 #include <door.h>
31 #include <unistd.h>
32 #include <stddef.h>
33 #include <stdlib.h>
34 #include <string.h>
35 #include <strings.h>
36 #include <synch.h>
37 #include <sys/stat.h>
38 #include <librcm_impl.h>
39
40 #include "librcm_event.h"
41
42 #define dprint if (debug) (void) printf
43 static int debug = 1;
44
45 #define BUF_THRESHOLD 1024 /* larger bufs require a free */
46
47 /*
48 * Lookup seq_num. We can not use the standard nvlist_lookup functions since
49 * the nvlist is not allocated with NV_UNIQUE_NAME or NV_UNIQUE_NAME_TYPE.
50 */
51 static int
lookup_seq_num(nvlist_t * nvl,uint64_t * seq_num)52 lookup_seq_num(nvlist_t *nvl, uint64_t *seq_num)
53 {
54 nvpair_t *nvp = NULL;
55
56 while ((nvp = nvlist_next_nvpair(nvl, nvp)) != NULL) {
57 if (strcmp(nvpair_name(nvp), RCM_SEQ_NUM) == 0 &&
58 nvpair_type(nvp) == DATA_TYPE_UINT64)
59 return (nvpair_value_uint64(nvp, seq_num));
60 }
61
62 return (ENOENT);
63 }
64
65 /*
66 * Get event service from a named door.
67 *
68 * This is similar to sysevent_post_event(), except that it deals with
69 * the "return buffer problem":
70 * Typically, the door service places the return buffer on the stack
71 * when calling door_return(). This places an artificial limit on the
72 * size of the return buffer.
73 * This problem is solved by placing large buffers on the heap, referenced
74 * through door_info. When client detects a large buffer, it will make a
75 * second door_call() to free the buffer. The client and the server agrees
76 * on a size, which is defined as BUF_THRESHOLD.
77 *
78 * Returns -1 if message not delivered. With errno set to cause of error.
79 * Returns 0 for success with the results returned in posting buffer.
80 */
81 int
get_event_service(char * door_name,void * data,size_t datalen,void ** result,size_t * rlen)82 get_event_service(char *door_name, void *data, size_t datalen,
83 void **result, size_t *rlen)
84 {
85 int service_door, error;
86 door_arg_t door_arg;
87
88 /*
89 * Open the service door
90 */
91 if ((service_door = open(door_name, O_RDONLY, 0)) == -1) {
92 errno = ESRCH;
93 return (-1);
94 }
95
96 retry1:
97 door_arg.rbuf = NULL; /* doorfs will provide return buf */
98 door_arg.rsize = 0;
99 door_arg.data_ptr = data;
100 door_arg.data_size = datalen;
101 door_arg.desc_ptr = NULL;
102 door_arg.desc_num = 0;
103
104 /*
105 * Make door call
106 * EAGAIN is returned when the door server is temporarily
107 * out of threads to service the door call. So retry.
108 */
109 if ((error = door_call(service_door, &door_arg)) == -1 &&
110 errno == EAGAIN) {
111 (void) sleep(1);
112 goto retry1;
113 }
114
115 if ((error == 0) && result) {
116
117 uint64_t seq_num = 0;
118
119 *result = NULL;
120 *rlen = 0;
121 if (door_arg.rbuf == NULL || door_arg.rsize == 0) {
122 dprint("bad return from door call\n");
123 (void) close(service_door);
124 errno = EFAULT;
125 return (-1);
126 }
127
128 (void) nvlist_unpack(door_arg.rbuf, door_arg.rsize,
129 (nvlist_t **)result, 0);
130 (void) munmap(door_arg.rbuf, door_arg.rsize);
131
132 /*
133 * If requiring a buf free, make another door call. There is
134 * no need to call munmap() after this door call, though.
135 */
136 if (lookup_seq_num((nvlist_t *)*result, &seq_num) == 0) {
137 retry2:
138 door_arg.rbuf = NULL;
139 door_arg.rsize = 0;
140 door_arg.data_ptr = (char *)&seq_num;
141 door_arg.data_size = sizeof (seq_num);
142 door_arg.desc_ptr = NULL;
143 door_arg.desc_num = 0;
144 if (door_call(service_door, &door_arg) == -1) {
145 if (errno == EAGAIN) {
146 (void) sleep(1);
147 goto retry2;
148 }
149 dprint("fail to free event buf in server\n");
150 }
151 }
152 }
153
154 (void) close(service_door);
155 return (error);
156 }
157
158 /*
159 * Export an event service door
160 */
161 struct door_result {
162 struct door_result *next;
163 void *data;
164 uint64_t seq_num;
165 };
166
167 typedef struct door_cookie {
168 uint64_t seq_num;
169 mutex_t door_lock;
170 void (*door_func)(void **, size_t *);
171 struct door_result *results;
172 } door_cookie_t;
173
174 /*
175 * add result to cookie, this is only invoked if result size > BUF_THRESHOLD
176 */
177 static void
add_door_result(door_cookie_t * cook,void * data,uint64_t seq_num)178 add_door_result(door_cookie_t *cook, void *data, uint64_t seq_num)
179 {
180 struct door_result *result;
181
182 /*
183 * Need a better way to handle memory here
184 */
185 result = malloc(sizeof (*result));
186 while (result == NULL) {
187 (void) sleep(1);
188 result = malloc(sizeof (*result));
189 }
190 result->next = NULL;
191 result->data = data;
192 result->seq_num = seq_num;
193
194 /*
195 * Attach current door result to the door cookie
196 */
197 (void) mutex_lock(&cook->door_lock);
198 if (cook->results == NULL) {
199 cook->results = result;
200 } else {
201 struct door_result *tmp = cook->results;
202 while (tmp->next) {
203 tmp = tmp->next;
204 }
205 tmp->next = result;
206 }
207 (void) mutex_unlock(&cook->door_lock);
208 }
209
210 /*
211 * free a previous door result as described by number.
212 */
213 static void
free_door_result(door_cookie_t * cook,uint64_t num)214 free_door_result(door_cookie_t *cook, uint64_t num)
215 {
216 struct door_result *prev = NULL, *tmp;
217
218 (void) mutex_lock(&cook->door_lock);
219 tmp = cook->results;
220 while (tmp && tmp->seq_num != num) {
221 prev = tmp;
222 tmp = tmp->next;
223 }
224
225 if (tmp == NULL) {
226 dprint("attempting to free nonexistent buf: %llu\n",
227 (unsigned long long)num);
228 (void) mutex_unlock(&cook->door_lock);
229 return;
230 }
231
232 if (prev) {
233 prev->next = tmp->next;
234 } else {
235 cook->results = tmp->next;
236 }
237 (void) mutex_unlock(&cook->door_lock);
238
239 free(tmp->data);
240 free(tmp);
241 }
242
243 /*ARGSUSED*/
244 static void
door_service(void * cookie,char * args,size_t alen,door_desc_t * ddp,uint_t ndid)245 door_service(void *cookie, char *args, size_t alen,
246 door_desc_t *ddp, uint_t ndid)
247 {
248 nvlist_t *nvl;
249 size_t nvl_size = 0;
250 char rbuf[BUF_THRESHOLD];
251 door_cookie_t *cook = (door_cookie_t *)cookie;
252 uint64_t seq_num = 0;
253
254 /*
255 * Special case for asking to free buffer
256 */
257 if (alen == sizeof (uint64_t)) {
258 free_door_result(cookie, *(uint64_t *)(void *)args);
259 (void) door_return(NULL, 0, NULL, 0);
260 }
261
262 /*
263 * door_func update args to point to return results.
264 * memory for results are dynamically allocated.
265 */
266 (*cook->door_func)((void **)&args, &alen);
267
268 /*
269 * If no results, just return
270 */
271 if (args == NULL) {
272 dprint("null results returned from door_func().\n");
273 (void) door_return(NULL, 0, NULL, 0);
274 }
275
276 /* Determine the size of the packed nvlist */
277 nvl = (nvlist_t *)(void *)args;
278 args = NULL;
279 alen = 0;
280 if (errno = nvlist_size(nvl, &nvl_size, NV_ENCODE_NATIVE)) {
281 nvlist_free(nvl);
282 dprint("failure to sizeup door results: %s\n", strerror(errno));
283 (void) door_return(NULL, 0, NULL, 0);
284 }
285
286 /*
287 * If the size of the packed nvlist would exceed the buffer threshold
288 * then get a sequence number and add it to the nvlist.
289 */
290 if (nvl_size > BUF_THRESHOLD) {
291 (void) mutex_lock(&cook->door_lock);
292 cook->seq_num++;
293 seq_num = cook->seq_num;
294 (void) mutex_unlock(&cook->door_lock);
295 (void) nvlist_add_uint64(nvl, RCM_SEQ_NUM, seq_num);
296 }
297
298 /* Refill the args with a packed version of the nvlist */
299 if (errno = nvlist_pack(nvl, &args, &alen, NV_ENCODE_NATIVE, 0)) {
300 nvlist_free(nvl);
301 dprint("failure to pack door results: %s\n", strerror(errno));
302 (void) door_return(NULL, 0, NULL, 0);
303 }
304 nvlist_free(nvl);
305
306 /*
307 * Based on the size of the packed nvlist, either use the local buffer
308 * or add it to the results list.
309 */
310 if (alen <= BUF_THRESHOLD) {
311 bcopy(args, rbuf, alen);
312 (void) free(args);
313 args = rbuf;
314 } else {
315 /*
316 * for long data, append results to end of queue in cook
317 * and set ndid, ask client to do another door_call
318 * to free the buffer.
319 */
320 add_door_result(cook, args, seq_num);
321 }
322
323 (void) door_return(args, alen, NULL, 0);
324 }
325
326 int
create_event_service(char * door_name,void (* func)(void ** data,size_t * datalen))327 create_event_service(char *door_name,
328 void (*func)(void **data, size_t *datalen))
329 {
330 int service_door, fd;
331 door_cookie_t *cookie;
332
333 /* create an fs file */
334 fd = open(door_name, O_EXCL|O_CREAT, S_IREAD|S_IWRITE);
335 if ((fd == -1) && (errno != EEXIST)) {
336 return (-1);
337 }
338 (void) close(fd);
339
340 /* allocate space for door cookie */
341 if ((cookie = calloc(1, sizeof (*cookie))) == NULL) {
342 return (-1);
343 }
344
345 cookie->door_func = func;
346 if ((service_door = door_create(door_service, (void *)cookie,
347 DOOR_REFUSE_DESC | DOOR_NO_CANCEL)) == -1) {
348 dprint("door create failed: %s\n", strerror(errno));
349 free(cookie);
350 return (-1);
351 }
352
353 retry:
354 (void) fdetach(door_name);
355 if (fattach(service_door, door_name) != 0) {
356 if (errno == EBUSY) {
357 /*
358 * EBUSY error may occur if anyone references the door
359 * file while we are fattach'ing. Since librcm, in the
360 * the process context of a DR initiator program, may
361 * reference the door file (via open/close/stat/
362 * door_call etc.) while we are still fattach'ing,
363 * retry on EBUSY.
364 */
365 goto retry;
366 }
367 dprint("door attaching failed: %s\n", strerror(errno));
368 free(cookie);
369 (void) close(service_door);
370 return (-1);
371 }
372
373 return (service_door);
374 }
375
376 int
revoke_event_service(int fd)377 revoke_event_service(int fd)
378 {
379 struct door_info info;
380 door_cookie_t *cookie;
381
382 if (door_info(fd, &info) == -1) {
383 return (-1);
384 }
385
386 if (door_revoke(fd) != 0) {
387 return (-1);
388 }
389
390 /* wait for existing door calls to finish */
391 (void) sleep(1);
392
393 if ((cookie = (door_cookie_t *)(uintptr_t)info.di_data) != NULL) {
394 struct door_result *tmp = cookie->results;
395 while (tmp) {
396 cookie->results = tmp->next;
397 free(tmp->data);
398 free(tmp);
399 tmp = cookie->results;
400 }
401 free(cookie);
402 }
403 return (0);
404 }
405