xref: /openbmc/linux/net/9p/protocol.c (revision 861e10be) 
1 /*
2  * net/9p/protocol.c
3  *
4  * 9P Protocol Support Code
5  *
6  *  Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
7  *
8  *  Base on code from Anthony Liguori <aliguori@us.ibm.com>
9  *  Copyright (C) 2008 by IBM, Corp.
10  *
11  *  This program is free software; you can redistribute it and/or modify
12  *  it under the terms of the GNU General Public License version 2
13  *  as published by the Free Software Foundation.
14  *
15  *  This program is distributed in the hope that it will be useful,
16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  *  GNU General Public License for more details.
19  *
20  *  You should have received a copy of the GNU General Public License
21  *  along with this program; if not, write to:
22  *  Free Software Foundation
23  *  51 Franklin Street, Fifth Floor
24  *  Boston, MA  02111-1301  USA
25  *
26  */
27 
28 #include <linux/module.h>
29 #include <linux/errno.h>
30 #include <linux/kernel.h>
31 #include <linux/uaccess.h>
32 #include <linux/slab.h>
33 #include <linux/sched.h>
34 #include <linux/stddef.h>
35 #include <linux/types.h>
36 #include <net/9p/9p.h>
37 #include <net/9p/client.h>
38 #include "protocol.h"
39 
40 #include <trace/events/9p.h>
41 
42 static int
43 p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...);
44 
45 void p9stat_free(struct p9_wstat *stbuf)
46 {
47 	kfree(stbuf->name);
48 	kfree(stbuf->uid);
49 	kfree(stbuf->gid);
50 	kfree(stbuf->muid);
51 	kfree(stbuf->extension);
52 }
53 EXPORT_SYMBOL(p9stat_free);
54 
55 size_t pdu_read(struct p9_fcall *pdu, void *data, size_t size)
56 {
57 	size_t len = min(pdu->size - pdu->offset, size);
58 	memcpy(data, &pdu->sdata[pdu->offset], len);
59 	pdu->offset += len;
60 	return size - len;
61 }
62 
63 static size_t pdu_write(struct p9_fcall *pdu, const void *data, size_t size)
64 {
65 	size_t len = min(pdu->capacity - pdu->size, size);
66 	memcpy(&pdu->sdata[pdu->size], data, len);
67 	pdu->size += len;
68 	return size - len;
69 }
70 
71 static size_t
72 pdu_write_u(struct p9_fcall *pdu, const char __user *udata, size_t size)
73 {
74 	size_t len = min(pdu->capacity - pdu->size, size);
75 	if (copy_from_user(&pdu->sdata[pdu->size], udata, len))
76 		len = 0;
77 
78 	pdu->size += len;
79 	return size - len;
80 }
81 
82 /*
83 	b - int8_t
84 	w - int16_t
85 	d - int32_t
86 	q - int64_t
87 	s - string
88 	S - stat
89 	Q - qid
90 	D - data blob (int32_t size followed by void *, results are not freed)
91 	T - array of strings (int16_t count, followed by strings)
92 	R - array of qids (int16_t count, followed by qids)
93 	A - stat for 9p2000.L (p9_stat_dotl)
94 	? - if optional = 1, continue parsing
95 */
96 
97 static int
98 p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt,
99 	va_list ap)
100 {
101 	const char *ptr;
102 	int errcode = 0;
103 
104 	for (ptr = fmt; *ptr; ptr++) {
105 		switch (*ptr) {
106 		case 'b':{
107 				int8_t *val = va_arg(ap, int8_t *);
108 				if (pdu_read(pdu, val, sizeof(*val))) {
109 					errcode = -EFAULT;
110 					break;
111 				}
112 			}
113 			break;
114 		case 'w':{
115 				int16_t *val = va_arg(ap, int16_t *);
116 				__le16 le_val;
117 				if (pdu_read(pdu, &le_val, sizeof(le_val))) {
118 					errcode = -EFAULT;
119 					break;
120 				}
121 				*val = le16_to_cpu(le_val);
122 			}
123 			break;
124 		case 'd':{
125 				int32_t *val = va_arg(ap, int32_t *);
126 				__le32 le_val;
127 				if (pdu_read(pdu, &le_val, sizeof(le_val))) {
128 					errcode = -EFAULT;
129 					break;
130 				}
131 				*val = le32_to_cpu(le_val);
132 			}
133 			break;
134 		case 'q':{
135 				int64_t *val = va_arg(ap, int64_t *);
136 				__le64 le_val;
137 				if (pdu_read(pdu, &le_val, sizeof(le_val))) {
138 					errcode = -EFAULT;
139 					break;
140 				}
141 				*val = le64_to_cpu(le_val);
142 			}
143 			break;
144 		case 's':{
145 				char **sptr = va_arg(ap, char **);
146 				uint16_t len;
147 
148 				errcode = p9pdu_readf(pdu, proto_version,
149 								"w", &len);
150 				if (errcode)
151 					break;
152 
153 				*sptr = kmalloc(len + 1, GFP_NOFS);
154 				if (*sptr == NULL) {
155 					errcode = -EFAULT;
156 					break;
157 				}
158 				if (pdu_read(pdu, *sptr, len)) {
159 					errcode = -EFAULT;
160 					kfree(*sptr);
161 					*sptr = NULL;
162 				} else
163 					(*sptr)[len] = 0;
164 			}
165 			break;
166 		case 'Q':{
167 				struct p9_qid *qid =
168 				    va_arg(ap, struct p9_qid *);
169 
170 				errcode = p9pdu_readf(pdu, proto_version, "bdq",
171 						      &qid->type, &qid->version,
172 						      &qid->path);
173 			}
174 			break;
175 		case 'S':{
176 				struct p9_wstat *stbuf =
177 				    va_arg(ap, struct p9_wstat *);
178 
179 				memset(stbuf, 0, sizeof(struct p9_wstat));
180 				stbuf->n_uid = stbuf->n_gid = stbuf->n_muid =
181 									-1;
182 				errcode =
183 				    p9pdu_readf(pdu, proto_version,
184 						"wwdQdddqssss?sddd",
185 						&stbuf->size, &stbuf->type,
186 						&stbuf->dev, &stbuf->qid,
187 						&stbuf->mode, &stbuf->atime,
188 						&stbuf->mtime, &stbuf->length,
189 						&stbuf->name, &stbuf->uid,
190 						&stbuf->gid, &stbuf->muid,
191 						&stbuf->extension,
192 						&stbuf->n_uid, &stbuf->n_gid,
193 						&stbuf->n_muid);
194 				if (errcode)
195 					p9stat_free(stbuf);
196 			}
197 			break;
198 		case 'D':{
199 				uint32_t *count = va_arg(ap, uint32_t *);
200 				void **data = va_arg(ap, void **);
201 
202 				errcode =
203 				    p9pdu_readf(pdu, proto_version, "d", count);
204 				if (!errcode) {
205 					*count =
206 					    min_t(uint32_t, *count,
207 						  pdu->size - pdu->offset);
208 					*data = &pdu->sdata[pdu->offset];
209 				}
210 			}
211 			break;
212 		case 'T':{
213 				uint16_t *nwname = va_arg(ap, uint16_t *);
214 				char ***wnames = va_arg(ap, char ***);
215 
216 				errcode = p9pdu_readf(pdu, proto_version,
217 								"w", nwname);
218 				if (!errcode) {
219 					*wnames =
220 					    kmalloc(sizeof(char *) * *nwname,
221 						    GFP_NOFS);
222 					if (!*wnames)
223 						errcode = -ENOMEM;
224 				}
225 
226 				if (!errcode) {
227 					int i;
228 
229 					for (i = 0; i < *nwname; i++) {
230 						errcode =
231 						    p9pdu_readf(pdu,
232 								proto_version,
233 								"s",
234 								&(*wnames)[i]);
235 						if (errcode)
236 							break;
237 					}
238 				}
239 
240 				if (errcode) {
241 					if (*wnames) {
242 						int i;
243 
244 						for (i = 0; i < *nwname; i++)
245 							kfree((*wnames)[i]);
246 					}
247 					kfree(*wnames);
248 					*wnames = NULL;
249 				}
250 			}
251 			break;
252 		case 'R':{
253 				int16_t *nwqid = va_arg(ap, int16_t *);
254 				struct p9_qid **wqids =
255 				    va_arg(ap, struct p9_qid **);
256 
257 				*wqids = NULL;
258 
259 				errcode =
260 				    p9pdu_readf(pdu, proto_version, "w", nwqid);
261 				if (!errcode) {
262 					*wqids =
263 					    kmalloc(*nwqid *
264 						    sizeof(struct p9_qid),
265 						    GFP_NOFS);
266 					if (*wqids == NULL)
267 						errcode = -ENOMEM;
268 				}
269 
270 				if (!errcode) {
271 					int i;
272 
273 					for (i = 0; i < *nwqid; i++) {
274 						errcode =
275 						    p9pdu_readf(pdu,
276 								proto_version,
277 								"Q",
278 								&(*wqids)[i]);
279 						if (errcode)
280 							break;
281 					}
282 				}
283 
284 				if (errcode) {
285 					kfree(*wqids);
286 					*wqids = NULL;
287 				}
288 			}
289 			break;
290 		case 'A': {
291 				struct p9_stat_dotl *stbuf =
292 				    va_arg(ap, struct p9_stat_dotl *);
293 
294 				memset(stbuf, 0, sizeof(struct p9_stat_dotl));
295 				errcode =
296 				    p9pdu_readf(pdu, proto_version,
297 					"qQdddqqqqqqqqqqqqqqq",
298 					&stbuf->st_result_mask,
299 					&stbuf->qid,
300 					&stbuf->st_mode,
301 					&stbuf->st_uid, &stbuf->st_gid,
302 					&stbuf->st_nlink,
303 					&stbuf->st_rdev, &stbuf->st_size,
304 					&stbuf->st_blksize, &stbuf->st_blocks,
305 					&stbuf->st_atime_sec,
306 					&stbuf->st_atime_nsec,
307 					&stbuf->st_mtime_sec,
308 					&stbuf->st_mtime_nsec,
309 					&stbuf->st_ctime_sec,
310 					&stbuf->st_ctime_nsec,
311 					&stbuf->st_btime_sec,
312 					&stbuf->st_btime_nsec,
313 					&stbuf->st_gen,
314 					&stbuf->st_data_version);
315 			}
316 			break;
317 		case '?':
318 			if ((proto_version != p9_proto_2000u) &&
319 				(proto_version != p9_proto_2000L))
320 				return 0;
321 			break;
322 		default:
323 			BUG();
324 			break;
325 		}
326 
327 		if (errcode)
328 			break;
329 	}
330 
331 	return errcode;
332 }
333 
334 int
335 p9pdu_vwritef(struct p9_fcall *pdu, int proto_version, const char *fmt,
336 	va_list ap)
337 {
338 	const char *ptr;
339 	int errcode = 0;
340 
341 	for (ptr = fmt; *ptr; ptr++) {
342 		switch (*ptr) {
343 		case 'b':{
344 				int8_t val = va_arg(ap, int);
345 				if (pdu_write(pdu, &val, sizeof(val)))
346 					errcode = -EFAULT;
347 			}
348 			break;
349 		case 'w':{
350 				__le16 val = cpu_to_le16(va_arg(ap, int));
351 				if (pdu_write(pdu, &val, sizeof(val)))
352 					errcode = -EFAULT;
353 			}
354 			break;
355 		case 'd':{
356 				__le32 val = cpu_to_le32(va_arg(ap, int32_t));
357 				if (pdu_write(pdu, &val, sizeof(val)))
358 					errcode = -EFAULT;
359 			}
360 			break;
361 		case 'q':{
362 				__le64 val = cpu_to_le64(va_arg(ap, int64_t));
363 				if (pdu_write(pdu, &val, sizeof(val)))
364 					errcode = -EFAULT;
365 			}
366 			break;
367 		case 's':{
368 				const char *sptr = va_arg(ap, const char *);
369 				uint16_t len = 0;
370 				if (sptr)
371 					len = min_t(size_t, strlen(sptr),
372 								USHRT_MAX);
373 
374 				errcode = p9pdu_writef(pdu, proto_version,
375 								"w", len);
376 				if (!errcode && pdu_write(pdu, sptr, len))
377 					errcode = -EFAULT;
378 			}
379 			break;
380 		case 'Q':{
381 				const struct p9_qid *qid =
382 				    va_arg(ap, const struct p9_qid *);
383 				errcode =
384 				    p9pdu_writef(pdu, proto_version, "bdq",
385 						 qid->type, qid->version,
386 						 qid->path);
387 			} break;
388 		case 'S':{
389 				const struct p9_wstat *stbuf =
390 				    va_arg(ap, const struct p9_wstat *);
391 				errcode =
392 				    p9pdu_writef(pdu, proto_version,
393 						 "wwdQdddqssss?sddd",
394 						 stbuf->size, stbuf->type,
395 						 stbuf->dev, &stbuf->qid,
396 						 stbuf->mode, stbuf->atime,
397 						 stbuf->mtime, stbuf->length,
398 						 stbuf->name, stbuf->uid,
399 						 stbuf->gid, stbuf->muid,
400 						 stbuf->extension, stbuf->n_uid,
401 						 stbuf->n_gid, stbuf->n_muid);
402 			} break;
403 		case 'D':{
404 				uint32_t count = va_arg(ap, uint32_t);
405 				const void *data = va_arg(ap, const void *);
406 
407 				errcode = p9pdu_writef(pdu, proto_version, "d",
408 									count);
409 				if (!errcode && pdu_write(pdu, data, count))
410 					errcode = -EFAULT;
411 			}
412 			break;
413 		case 'U':{
414 				int32_t count = va_arg(ap, int32_t);
415 				const char __user *udata =
416 						va_arg(ap, const void __user *);
417 				errcode = p9pdu_writef(pdu, proto_version, "d",
418 									count);
419 				if (!errcode && pdu_write_u(pdu, udata, count))
420 					errcode = -EFAULT;
421 			}
422 			break;
423 		case 'T':{
424 				uint16_t nwname = va_arg(ap, int);
425 				const char **wnames = va_arg(ap, const char **);
426 
427 				errcode = p9pdu_writef(pdu, proto_version, "w",
428 									nwname);
429 				if (!errcode) {
430 					int i;
431 
432 					for (i = 0; i < nwname; i++) {
433 						errcode =
434 						    p9pdu_writef(pdu,
435 								proto_version,
436 								 "s",
437 								 wnames[i]);
438 						if (errcode)
439 							break;
440 					}
441 				}
442 			}
443 			break;
444 		case 'R':{
445 				int16_t nwqid = va_arg(ap, int);
446 				struct p9_qid *wqids =
447 				    va_arg(ap, struct p9_qid *);
448 
449 				errcode = p9pdu_writef(pdu, proto_version, "w",
450 									nwqid);
451 				if (!errcode) {
452 					int i;
453 
454 					for (i = 0; i < nwqid; i++) {
455 						errcode =
456 						    p9pdu_writef(pdu,
457 								proto_version,
458 								 "Q",
459 								 &wqids[i]);
460 						if (errcode)
461 							break;
462 					}
463 				}
464 			}
465 			break;
466 		case 'I':{
467 				struct p9_iattr_dotl *p9attr = va_arg(ap,
468 							struct p9_iattr_dotl *);
469 
470 				errcode = p9pdu_writef(pdu, proto_version,
471 							"ddddqqqqq",
472 							p9attr->valid,
473 							p9attr->mode,
474 							p9attr->uid,
475 							p9attr->gid,
476 							p9attr->size,
477 							p9attr->atime_sec,
478 							p9attr->atime_nsec,
479 							p9attr->mtime_sec,
480 							p9attr->mtime_nsec);
481 			}
482 			break;
483 		case '?':
484 			if ((proto_version != p9_proto_2000u) &&
485 				(proto_version != p9_proto_2000L))
486 				return 0;
487 			break;
488 		default:
489 			BUG();
490 			break;
491 		}
492 
493 		if (errcode)
494 			break;
495 	}
496 
497 	return errcode;
498 }
499 
500 int p9pdu_readf(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
501 {
502 	va_list ap;
503 	int ret;
504 
505 	va_start(ap, fmt);
506 	ret = p9pdu_vreadf(pdu, proto_version, fmt, ap);
507 	va_end(ap);
508 
509 	return ret;
510 }
511 
512 static int
513 p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
514 {
515 	va_list ap;
516 	int ret;
517 
518 	va_start(ap, fmt);
519 	ret = p9pdu_vwritef(pdu, proto_version, fmt, ap);
520 	va_end(ap);
521 
522 	return ret;
523 }
524 
525 int p9stat_read(struct p9_client *clnt, char *buf, int len, struct p9_wstat *st)
526 {
527 	struct p9_fcall fake_pdu;
528 	int ret;
529 
530 	fake_pdu.size = len;
531 	fake_pdu.capacity = len;
532 	fake_pdu.sdata = buf;
533 	fake_pdu.offset = 0;
534 
535 	ret = p9pdu_readf(&fake_pdu, clnt->proto_version, "S", st);
536 	if (ret) {
537 		p9_debug(P9_DEBUG_9P, "<<< p9stat_read failed: %d\n", ret);
538 		trace_9p_protocol_dump(clnt, &fake_pdu);
539 	}
540 
541 	return ret;
542 }
543 EXPORT_SYMBOL(p9stat_read);
544 
545 int p9pdu_prepare(struct p9_fcall *pdu, int16_t tag, int8_t type)
546 {
547 	pdu->id = type;
548 	return p9pdu_writef(pdu, 0, "dbw", 0, type, tag);
549 }
550 
551 int p9pdu_finalize(struct p9_client *clnt, struct p9_fcall *pdu)
552 {
553 	int size = pdu->size;
554 	int err;
555 
556 	pdu->size = 0;
557 	err = p9pdu_writef(pdu, 0, "d", size);
558 	pdu->size = size;
559 
560 	trace_9p_protocol_dump(clnt, pdu);
561 	p9_debug(P9_DEBUG_9P, ">>> size=%d type: %d tag: %d\n",
562 		 pdu->size, pdu->id, pdu->tag);
563 
564 	return err;
565 }
566 
567 void p9pdu_reset(struct p9_fcall *pdu)
568 {
569 	pdu->offset = 0;
570 	pdu->size = 0;
571 }
572 
573 int p9dirent_read(struct p9_client *clnt, char *buf, int len,
574 		  struct p9_dirent *dirent)
575 {
576 	struct p9_fcall fake_pdu;
577 	int ret;
578 	char *nameptr;
579 
580 	fake_pdu.size = len;
581 	fake_pdu.capacity = len;
582 	fake_pdu.sdata = buf;
583 	fake_pdu.offset = 0;
584 
585 	ret = p9pdu_readf(&fake_pdu, clnt->proto_version, "Qqbs", &dirent->qid,
586 			  &dirent->d_off, &dirent->d_type, &nameptr);
587 	if (ret) {
588 		p9_debug(P9_DEBUG_9P, "<<< p9dirent_read failed: %d\n", ret);
589 		trace_9p_protocol_dump(clnt, &fake_pdu);
590 		goto out;
591 	}
592 
593 	strcpy(dirent->d_name, nameptr);
594 	kfree(nameptr);
595 
596 out:
597 	return fake_pdu.offset;
598 }
599 EXPORT_SYMBOL(p9dirent_read);
600