1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2005 Michael Bushkov <bushman@rsu.ru>
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
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. 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 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 */
29
30 #include <sys/cdefs.h>
31 #include "namespace.h"
32 #include <sys/types.h>
33 #include <sys/socket.h>
34 #include <sys/event.h>
35 #include <sys/uio.h>
36 #include <sys/un.h>
37 #include <assert.h>
38 #include <errno.h>
39 #include <fcntl.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <unistd.h>
43 #include "un-namespace.h"
44 #include "nscachedcli.h"
45
46 #define NS_DEFAULT_CACHED_IO_TIMEOUT 4
47
48 static int safe_write(struct cached_connection_ *, const void *, size_t);
49 static int safe_read(struct cached_connection_ *, void *, size_t);
50 static int send_credentials(struct cached_connection_ *, int);
51
52 /*
53 * safe_write writes data to the specified connection and tries to do it in
54 * the very safe manner. We ensure, that we can write to the socket with
55 * kevent. If the data_size can't be sent in one piece, then it would be
56 * splitted.
57 */
58 static int
safe_write(struct cached_connection_ * connection,const void * data,size_t data_size)59 safe_write(struct cached_connection_ *connection, const void *data,
60 size_t data_size)
61 {
62 struct kevent eventlist;
63 int nevents;
64 size_t result;
65 ssize_t s_result;
66 struct timespec timeout;
67
68 if (data_size == 0)
69 return (0);
70
71 timeout.tv_sec = NS_DEFAULT_CACHED_IO_TIMEOUT;
72 timeout.tv_nsec = 0;
73 result = 0;
74 do {
75 nevents = _kevent(connection->write_queue, NULL, 0, &eventlist,
76 1, &timeout);
77 if ((nevents == 1) && (eventlist.filter == EVFILT_WRITE)) {
78 s_result = _sendto(connection->sockfd, data + result,
79 eventlist.data < data_size - result ?
80 eventlist.data : data_size - result, MSG_NOSIGNAL,
81 NULL, 0);
82 if (s_result == -1)
83 return (-1);
84 else
85 result += s_result;
86
87 if (eventlist.flags & EV_EOF)
88 return (result < data_size ? -1 : 0);
89 } else
90 return (-1);
91 } while (result < data_size);
92
93 return (0);
94 }
95
96 /*
97 * safe_read reads data from connection and tries to do it in the very safe
98 * and stable way. It uses kevent to ensure, that the data are available for
99 * reading. If the amount of data to be read is too large, then they would
100 * be splitted.
101 */
102 static int
safe_read(struct cached_connection_ * connection,void * data,size_t data_size)103 safe_read(struct cached_connection_ *connection, void *data, size_t data_size)
104 {
105 struct kevent eventlist;
106 size_t result;
107 ssize_t s_result;
108 struct timespec timeout;
109 int nevents;
110
111 if (data_size == 0)
112 return (0);
113
114 timeout.tv_sec = NS_DEFAULT_CACHED_IO_TIMEOUT;
115 timeout.tv_nsec = 0;
116 result = 0;
117 do {
118 nevents = _kevent(connection->read_queue, NULL, 0, &eventlist,
119 1, &timeout);
120 if (nevents == 1 && eventlist.filter == EVFILT_READ) {
121 s_result = _read(connection->sockfd, data + result,
122 eventlist.data <= data_size - result ?
123 eventlist.data : data_size - result);
124 if (s_result == -1)
125 return (-1);
126 else
127 result += s_result;
128
129 if (eventlist.flags & EV_EOF)
130 return (result < data_size ? -1 : 0);
131 } else
132 return (-1);
133 } while (result < data_size);
134
135 return (0);
136 }
137
138 /*
139 * Sends the credentials information to the connection along with the
140 * communication element type.
141 */
142 static int
send_credentials(struct cached_connection_ * connection,int type)143 send_credentials(struct cached_connection_ *connection, int type)
144 {
145 union {
146 struct cmsghdr hdr;
147 char pad[CMSG_SPACE(sizeof(struct cmsgcred))];
148 } cmsg;
149 struct msghdr mhdr;
150 struct iovec iov;
151 struct kevent eventlist;
152 int nevents;
153 ssize_t result;
154
155 memset(&cmsg, 0, sizeof(cmsg));
156 cmsg.hdr.cmsg_len = CMSG_LEN(sizeof(struct cmsgcred));
157 cmsg.hdr.cmsg_level = SOL_SOCKET;
158 cmsg.hdr.cmsg_type = SCM_CREDS;
159
160 memset(&mhdr, 0, sizeof(mhdr));
161 mhdr.msg_iov = &iov;
162 mhdr.msg_iovlen = 1;
163 mhdr.msg_control = &cmsg;
164 mhdr.msg_controllen = CMSG_SPACE(sizeof(struct cmsgcred));
165
166 iov.iov_base = &type;
167 iov.iov_len = sizeof(int);
168
169 EV_SET(&eventlist, connection->sockfd, EVFILT_WRITE, EV_ADD,
170 NOTE_LOWAT, sizeof(int), NULL);
171 (void)_kevent(connection->write_queue, &eventlist, 1, NULL, 0, NULL);
172
173 nevents = _kevent(connection->write_queue, NULL, 0, &eventlist, 1,
174 NULL);
175 if (nevents == 1 && eventlist.filter == EVFILT_WRITE) {
176 result = _sendmsg(connection->sockfd, &mhdr,
177 MSG_NOSIGNAL) == -1 ? -1 : 0;
178 EV_SET(&eventlist, connection->sockfd, EVFILT_WRITE, EV_ADD,
179 0, 0, NULL);
180 _kevent(connection->write_queue, &eventlist, 1, NULL, 0, NULL);
181 return (result);
182 } else
183 return (-1);
184 }
185
186 /*
187 * Opens the connection with the specified params. Initializes all kqueues.
188 */
189 struct cached_connection_ *
__open_cached_connection(struct cached_connection_params const * params)190 __open_cached_connection(struct cached_connection_params const *params)
191 {
192 struct cached_connection_ *retval;
193 struct kevent eventlist;
194 struct sockaddr_un client_address;
195 int client_address_len, client_socket;
196 int res;
197
198 assert(params != NULL);
199
200 client_socket = _socket(PF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0);
201 client_address.sun_family = PF_LOCAL;
202 strncpy(client_address.sun_path, params->socket_path,
203 sizeof(client_address.sun_path));
204 client_address_len = sizeof(client_address.sun_family) +
205 strlen(client_address.sun_path) + 1;
206
207 res = _connect(client_socket, (struct sockaddr *)&client_address,
208 client_address_len);
209 if (res == -1) {
210 _close(client_socket);
211 return (NULL);
212 }
213 _fcntl(client_socket, F_SETFL, O_NONBLOCK);
214
215 retval = malloc(sizeof(struct cached_connection_));
216 assert(retval != NULL);
217 memset(retval, 0, sizeof(struct cached_connection_));
218
219 retval->sockfd = client_socket;
220
221 retval->write_queue = kqueue();
222 assert(retval->write_queue != -1);
223
224 EV_SET(&eventlist, retval->sockfd, EVFILT_WRITE, EV_ADD, 0, 0, NULL);
225 res = _kevent(retval->write_queue, &eventlist, 1, NULL, 0, NULL);
226
227 retval->read_queue = kqueue();
228 assert(retval->read_queue != -1);
229
230 EV_SET(&eventlist, retval->sockfd, EVFILT_READ, EV_ADD, 0, 0, NULL);
231 res = _kevent(retval->read_queue, &eventlist, 1, NULL, 0, NULL);
232
233 return (retval);
234 }
235
236 void
__close_cached_connection(struct cached_connection_ * connection)237 __close_cached_connection(struct cached_connection_ *connection)
238 {
239 assert(connection != NULL);
240
241 _close(connection->sockfd);
242 _close(connection->read_queue);
243 _close(connection->write_queue);
244 free(connection);
245 }
246
247 /*
248 * This function is very close to the cache_write function of the caching
249 * library, which is used in the caching daemon. It caches the data with the
250 * specified key in the cache entry with entry_name.
251 */
252 int
__cached_write(struct cached_connection_ * connection,const char * entry_name,const char * key,size_t key_size,const char * data,size_t data_size)253 __cached_write(struct cached_connection_ *connection, const char *entry_name,
254 const char *key, size_t key_size, const char *data, size_t data_size)
255 {
256 size_t name_size;
257 int error_code;
258 int result;
259
260 error_code = -1;
261 result = 0;
262 result = send_credentials(connection, CET_WRITE_REQUEST);
263 if (result != 0)
264 goto fin;
265
266 name_size = strlen(entry_name);
267 result = safe_write(connection, &name_size, sizeof(size_t));
268 if (result != 0)
269 goto fin;
270
271 result = safe_write(connection, &key_size, sizeof(size_t));
272 if (result != 0)
273 goto fin;
274
275 result = safe_write(connection, &data_size, sizeof(size_t));
276 if (result != 0)
277 goto fin;
278
279 result = safe_write(connection, entry_name, name_size);
280 if (result != 0)
281 goto fin;
282
283 result = safe_write(connection, key, key_size);
284 if (result != 0)
285 goto fin;
286
287 result = safe_write(connection, data, data_size);
288 if (result != 0)
289 goto fin;
290
291 result = safe_read(connection, &error_code, sizeof(int));
292 if (result != 0)
293 error_code = -1;
294
295 fin:
296 return (error_code);
297 }
298
299 /*
300 * This function is very close to the cache_read function of the caching
301 * library, which is used in the caching daemon. It reads cached data with the
302 * specified key from the cache entry with entry_name.
303 */
304 int
__cached_read(struct cached_connection_ * connection,const char * entry_name,const char * key,size_t key_size,char * data,size_t * data_size)305 __cached_read(struct cached_connection_ *connection, const char *entry_name,
306 const char *key, size_t key_size, char *data, size_t *data_size)
307 {
308 size_t name_size, result_size;
309 int error_code, rec_error_code;
310 int result;
311
312 assert(connection != NULL);
313 result = 0;
314 error_code = -1;
315
316 result = send_credentials(connection, CET_READ_REQUEST);
317 if (result != 0)
318 goto fin;
319
320 name_size = strlen(entry_name);
321 result = safe_write(connection, &name_size, sizeof(size_t));
322 if (result != 0)
323 goto fin;
324
325 result = safe_write(connection, &key_size, sizeof(size_t));
326 if (result != 0)
327 goto fin;
328
329 result = safe_write(connection, entry_name, name_size);
330 if (result != 0)
331 goto fin;
332
333 result = safe_write(connection, key, key_size);
334 if (result != 0)
335 goto fin;
336
337 result = safe_read(connection, &rec_error_code, sizeof(int));
338 if (result != 0)
339 goto fin;
340
341 if (rec_error_code != 0) {
342 error_code = rec_error_code;
343 goto fin;
344 }
345
346 result = safe_read(connection, &result_size, sizeof(size_t));
347 if (result != 0)
348 goto fin;
349
350 if (result_size > *data_size) {
351 *data_size = result_size;
352 error_code = -2;
353 goto fin;
354 }
355
356 result = safe_read(connection, data, result_size);
357 if (result != 0)
358 goto fin;
359
360 *data_size = result_size;
361 error_code = 0;
362
363 fin:
364 return (error_code);
365 }
366
367 /*
368 * Initializes the mp_write_session. For such a session the new connection
369 * would be opened. The data should be written to the session with
370 * __cached_mp_write function. The __close_cached_mp_write_session function
371 * should be used to submit session and __abandon_cached_mp_write_session - to
372 * abandon it. When the session is submitted, the whole se
373 */
374 struct cached_connection_ *
__open_cached_mp_write_session(struct cached_connection_params const * params,const char * entry_name)375 __open_cached_mp_write_session(struct cached_connection_params const *params,
376 const char *entry_name)
377 {
378 struct cached_connection_ *connection, *retval;
379 size_t name_size;
380 int error_code;
381 int result;
382
383 retval = NULL;
384 connection = __open_cached_connection(params);
385 if (connection == NULL)
386 return (NULL);
387 connection->mp_flag = 1;
388
389 result = send_credentials(connection, CET_MP_WRITE_SESSION_REQUEST);
390 if (result != 0)
391 goto fin;
392
393 name_size = strlen(entry_name);
394 result = safe_write(connection, &name_size, sizeof(size_t));
395 if (result != 0)
396 goto fin;
397
398 result = safe_write(connection, entry_name, name_size);
399 if (result != 0)
400 goto fin;
401
402 result = safe_read(connection, &error_code, sizeof(int));
403 if (result != 0)
404 goto fin;
405
406 if (error_code != 0)
407 result = error_code;
408
409 fin:
410 if (result != 0)
411 __close_cached_connection(connection);
412 else
413 retval = connection;
414 return (retval);
415 }
416
417 /*
418 * Adds new portion of data to the opened write session
419 */
420 int
__cached_mp_write(struct cached_connection_ * ws,const char * data,size_t data_size)421 __cached_mp_write(struct cached_connection_ *ws, const char *data,
422 size_t data_size)
423 {
424 int request, result;
425 int error_code;
426
427 error_code = -1;
428
429 request = CET_MP_WRITE_SESSION_WRITE_REQUEST;
430 result = safe_write(ws, &request, sizeof(int));
431 if (result != 0)
432 goto fin;
433
434 result = safe_write(ws, &data_size, sizeof(size_t));
435 if (result != 0)
436 goto fin;
437
438 result = safe_write(ws, data, data_size);
439 if (result != 0)
440 goto fin;
441
442 result = safe_read(ws, &error_code, sizeof(int));
443 if (result != 0)
444 error_code = -1;
445
446 fin:
447 return (error_code);
448 }
449
450 /*
451 * Abandons all operations with the write session. All data, that were written
452 * to the session before, are discarded.
453 */
454 int
__abandon_cached_mp_write_session(struct cached_connection_ * ws)455 __abandon_cached_mp_write_session(struct cached_connection_ *ws)
456 {
457 int notification;
458 int result;
459
460 notification = CET_MP_WRITE_SESSION_ABANDON_NOTIFICATION;
461 result = safe_write(ws, ¬ification, sizeof(int));
462 __close_cached_connection(ws);
463 return (result);
464 }
465
466 /*
467 * Gracefully closes the write session. The data, that were previously written
468 * to the session, are committed.
469 */
470 int
__close_cached_mp_write_session(struct cached_connection_ * ws)471 __close_cached_mp_write_session(struct cached_connection_ *ws)
472 {
473 int notification;
474
475 notification = CET_MP_WRITE_SESSION_CLOSE_NOTIFICATION;
476 (void)safe_write(ws, ¬ification, sizeof(int));
477 __close_cached_connection(ws);
478 return (0);
479 }
480
481 struct cached_connection_ *
__open_cached_mp_read_session(struct cached_connection_params const * params,const char * entry_name)482 __open_cached_mp_read_session(struct cached_connection_params const *params,
483 const char *entry_name)
484 {
485 struct cached_connection_ *connection, *retval;
486 size_t name_size;
487 int error_code;
488 int result;
489
490 retval = NULL;
491 connection = __open_cached_connection(params);
492 if (connection == NULL)
493 return (NULL);
494 connection->mp_flag = 1;
495
496 result = send_credentials(connection, CET_MP_READ_SESSION_REQUEST);
497 if (result != 0)
498 goto fin;
499
500 name_size = strlen(entry_name);
501 result = safe_write(connection, &name_size, sizeof(size_t));
502 if (result != 0)
503 goto fin;
504
505 result = safe_write(connection, entry_name, name_size);
506 if (result != 0)
507 goto fin;
508
509 result = safe_read(connection, &error_code, sizeof(int));
510 if (result != 0)
511 goto fin;
512
513 if (error_code != 0)
514 result = error_code;
515
516 fin:
517 if (result != 0)
518 __close_cached_connection(connection);
519 else
520 retval = connection;
521 return (retval);
522 }
523
524 int
__cached_mp_read(struct cached_connection_ * rs,char * data,size_t * data_size)525 __cached_mp_read(struct cached_connection_ *rs, char *data, size_t *data_size)
526 {
527 size_t result_size;
528 int error_code, rec_error_code;
529 int request, result;
530
531 error_code = -1;
532 request = CET_MP_READ_SESSION_READ_REQUEST;
533 result = safe_write(rs, &request, sizeof(int));
534 if (result != 0)
535 goto fin;
536
537 result = safe_read(rs, &rec_error_code, sizeof(int));
538 if (result != 0)
539 goto fin;
540
541 if (rec_error_code != 0) {
542 error_code = rec_error_code;
543 goto fin;
544 }
545
546 result = safe_read(rs, &result_size, sizeof(size_t));
547 if (result != 0)
548 goto fin;
549
550 if (result_size > *data_size) {
551 *data_size = result_size;
552 error_code = -2;
553 goto fin;
554 }
555
556 result = safe_read(rs, data, result_size);
557 if (result != 0)
558 goto fin;
559
560 *data_size = result_size;
561 error_code = 0;
562
563 fin:
564 return (error_code);
565 }
566
567 int
__close_cached_mp_read_session(struct cached_connection_ * rs)568 __close_cached_mp_read_session(struct cached_connection_ *rs)
569 {
570
571 __close_cached_connection(rs);
572 return (0);
573 }
574