xref: /linux/net/9p/protocol.c (revision bb9707077b4ee5f77bc9939b057ff8a0d410296f) 
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 <linux/uio.h>
37 #include <net/9p/9p.h>
38 #include <net/9p/client.h>
39 #include "protocol.h"
40 
41 #include <trace/events/9p.h>
42 
43 static int
44 p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...);
45 
46 void p9stat_free(struct p9_wstat *stbuf)
47 {
48 	kfree(stbuf->name);
49 	kfree(stbuf->uid);
50 	kfree(stbuf->gid);
51 	kfree(stbuf->muid);
52 	kfree(stbuf->extension);
53 }
54 EXPORT_SYMBOL(p9stat_free);
55 
56 size_t pdu_read(struct p9_fcall *pdu, void *data, size_t size)
57 {
58 	size_t len = min(pdu->size - pdu->offset, size);
59 	memcpy(data, &pdu->sdata[pdu->offset], len);
60 	pdu->offset += len;
61 	return size - len;
62 }
63 
64 static size_t pdu_write(struct p9_fcall *pdu, const void *data, size_t size)
65 {
66 	size_t len = min(pdu->capacity - pdu->size, size);
67 	memcpy(&pdu->sdata[pdu->size], data, len);
68 	pdu->size += len;
69 	return size - len;
70 }
71 
72 static size_t
73 pdu_write_u(struct p9_fcall *pdu, struct iov_iter *from, size_t size)
74 {
75 	size_t len = min(pdu->capacity - pdu->size, size);
76 	struct iov_iter i = *from;
77 	if (copy_from_iter(&pdu->sdata[pdu->size], len, &i) != len)
78 		len = 0;
79 
80 	pdu->size += len;
81 	return size - len;
82 }
83 
84 /*
85 	b - int8_t
86 	w - int16_t
87 	d - int32_t
88 	q - int64_t
89 	s - string
90 	u - numeric uid
91 	g - numeric gid
92 	S - stat
93 	Q - qid
94 	D - data blob (int32_t size followed by void *, results are not freed)
95 	T - array of strings (int16_t count, followed by strings)
96 	R - array of qids (int16_t count, followed by qids)
97 	A - stat for 9p2000.L (p9_stat_dotl)
98 	? - if optional = 1, continue parsing
99 */
100 
101 static int
102 p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt,
103 	va_list ap)
104 {
105 	const char *ptr;
106 	int errcode = 0;
107 
108 	for (ptr = fmt; *ptr; ptr++) {
109 		switch (*ptr) {
110 		case 'b':{
111 				int8_t *val = va_arg(ap, int8_t *);
112 				if (pdu_read(pdu, val, sizeof(*val))) {
113 					errcode = -EFAULT;
114 					break;
115 				}
116 			}
117 			break;
118 		case 'w':{
119 				int16_t *val = va_arg(ap, int16_t *);
120 				__le16 le_val;
121 				if (pdu_read(pdu, &le_val, sizeof(le_val))) {
122 					errcode = -EFAULT;
123 					break;
124 				}
125 				*val = le16_to_cpu(le_val);
126 			}
127 			break;
128 		case 'd':{
129 				int32_t *val = va_arg(ap, int32_t *);
130 				__le32 le_val;
131 				if (pdu_read(pdu, &le_val, sizeof(le_val))) {
132 					errcode = -EFAULT;
133 					break;
134 				}
135 				*val = le32_to_cpu(le_val);
136 			}
137 			break;
138 		case 'q':{
139 				int64_t *val = va_arg(ap, int64_t *);
140 				__le64 le_val;
141 				if (pdu_read(pdu, &le_val, sizeof(le_val))) {
142 					errcode = -EFAULT;
143 					break;
144 				}
145 				*val = le64_to_cpu(le_val);
146 			}
147 			break;
148 		case 's':{
149 				char **sptr = va_arg(ap, char **);
150 				uint16_t len;
151 
152 				errcode = p9pdu_readf(pdu, proto_version,
153 								"w", &len);
154 				if (errcode)
155 					break;
156 
157 				*sptr = kmalloc(len + 1, GFP_NOFS);
158 				if (*sptr == NULL) {
159 					errcode = -EFAULT;
160 					break;
161 				}
162 				if (pdu_read(pdu, *sptr, len)) {
163 					errcode = -EFAULT;
164 					kfree(*sptr);
165 					*sptr = NULL;
166 				} else
167 					(*sptr)[len] = 0;
168 			}
169 			break;
170 		case 'u': {
171 				kuid_t *uid = va_arg(ap, kuid_t *);
172 				__le32 le_val;
173 				if (pdu_read(pdu, &le_val, sizeof(le_val))) {
174 					errcode = -EFAULT;
175 					break;
176 				}
177 				*uid = make_kuid(&init_user_ns,
178 						 le32_to_cpu(le_val));
179 			} break;
180 		case 'g': {
181 				kgid_t *gid = va_arg(ap, kgid_t *);
182 				__le32 le_val;
183 				if (pdu_read(pdu, &le_val, sizeof(le_val))) {
184 					errcode = -EFAULT;
185 					break;
186 				}
187 				*gid = make_kgid(&init_user_ns,
188 						 le32_to_cpu(le_val));
189 			} break;
190 		case 'Q':{
191 				struct p9_qid *qid =
192 				    va_arg(ap, struct p9_qid *);
193 
194 				errcode = p9pdu_readf(pdu, proto_version, "bdq",
195 						      &qid->type, &qid->version,
196 						      &qid->path);
197 			}
198 			break;
199 		case 'S':{
200 				struct p9_wstat *stbuf =
201 				    va_arg(ap, struct p9_wstat *);
202 
203 				memset(stbuf, 0, sizeof(struct p9_wstat));
204 				stbuf->n_uid = stbuf->n_muid = INVALID_UID;
205 				stbuf->n_gid = INVALID_GID;
206 
207 				errcode =
208 				    p9pdu_readf(pdu, proto_version,
209 						"wwdQdddqssss?sugu",
210 						&stbuf->size, &stbuf->type,
211 						&stbuf->dev, &stbuf->qid,
212 						&stbuf->mode, &stbuf->atime,
213 						&stbuf->mtime, &stbuf->length,
214 						&stbuf->name, &stbuf->uid,
215 						&stbuf->gid, &stbuf->muid,
216 						&stbuf->extension,
217 						&stbuf->n_uid, &stbuf->n_gid,
218 						&stbuf->n_muid);
219 				if (errcode)
220 					p9stat_free(stbuf);
221 			}
222 			break;
223 		case 'D':{
224 				uint32_t *count = va_arg(ap, uint32_t *);
225 				void **data = va_arg(ap, void **);
226 
227 				errcode =
228 				    p9pdu_readf(pdu, proto_version, "d", count);
229 				if (!errcode) {
230 					*count =
231 					    min_t(uint32_t, *count,
232 						  pdu->size - pdu->offset);
233 					*data = &pdu->sdata[pdu->offset];
234 				}
235 			}
236 			break;
237 		case 'T':{
238 				uint16_t *nwname = va_arg(ap, uint16_t *);
239 				char ***wnames = va_arg(ap, char ***);
240 
241 				errcode = p9pdu_readf(pdu, proto_version,
242 								"w", nwname);
243 				if (!errcode) {
244 					*wnames =
245 					    kmalloc(sizeof(char *) * *nwname,
246 						    GFP_NOFS);
247 					if (!*wnames)
248 						errcode = -ENOMEM;
249 				}
250 
251 				if (!errcode) {
252 					int i;
253 
254 					for (i = 0; i < *nwname; i++) {
255 						errcode =
256 						    p9pdu_readf(pdu,
257 								proto_version,
258 								"s",
259 								&(*wnames)[i]);
260 						if (errcode)
261 							break;
262 					}
263 				}
264 
265 				if (errcode) {
266 					if (*wnames) {
267 						int i;
268 
269 						for (i = 0; i < *nwname; i++)
270 							kfree((*wnames)[i]);
271 					}
272 					kfree(*wnames);
273 					*wnames = NULL;
274 				}
275 			}
276 			break;
277 		case 'R':{
278 				uint16_t *nwqid = va_arg(ap, uint16_t *);
279 				struct p9_qid **wqids =
280 				    va_arg(ap, struct p9_qid **);
281 
282 				*wqids = NULL;
283 
284 				errcode =
285 				    p9pdu_readf(pdu, proto_version, "w", nwqid);
286 				if (!errcode) {
287 					*wqids =
288 					    kmalloc(*nwqid *
289 						    sizeof(struct p9_qid),
290 						    GFP_NOFS);
291 					if (*wqids == NULL)
292 						errcode = -ENOMEM;
293 				}
294 
295 				if (!errcode) {
296 					int i;
297 
298 					for (i = 0; i < *nwqid; i++) {
299 						errcode =
300 						    p9pdu_readf(pdu,
301 								proto_version,
302 								"Q",
303 								&(*wqids)[i]);
304 						if (errcode)
305 							break;
306 					}
307 				}
308 
309 				if (errcode) {
310 					kfree(*wqids);
311 					*wqids = NULL;
312 				}
313 			}
314 			break;
315 		case 'A': {
316 				struct p9_stat_dotl *stbuf =
317 				    va_arg(ap, struct p9_stat_dotl *);
318 
319 				memset(stbuf, 0, sizeof(struct p9_stat_dotl));
320 				errcode =
321 				    p9pdu_readf(pdu, proto_version,
322 					"qQdugqqqqqqqqqqqqqqq",
323 					&stbuf->st_result_mask,
324 					&stbuf->qid,
325 					&stbuf->st_mode,
326 					&stbuf->st_uid, &stbuf->st_gid,
327 					&stbuf->st_nlink,
328 					&stbuf->st_rdev, &stbuf->st_size,
329 					&stbuf->st_blksize, &stbuf->st_blocks,
330 					&stbuf->st_atime_sec,
331 					&stbuf->st_atime_nsec,
332 					&stbuf->st_mtime_sec,
333 					&stbuf->st_mtime_nsec,
334 					&stbuf->st_ctime_sec,
335 					&stbuf->st_ctime_nsec,
336 					&stbuf->st_btime_sec,
337 					&stbuf->st_btime_nsec,
338 					&stbuf->st_gen,
339 					&stbuf->st_data_version);
340 			}
341 			break;
342 		case '?':
343 			if ((proto_version != p9_proto_2000u) &&
344 				(proto_version != p9_proto_2000L))
345 				return 0;
346 			break;
347 		default:
348 			BUG();
349 			break;
350 		}
351 
352 		if (errcode)
353 			break;
354 	}
355 
356 	return errcode;
357 }
358 
359 int
360 p9pdu_vwritef(struct p9_fcall *pdu, int proto_version, const char *fmt,
361 	va_list ap)
362 {
363 	const char *ptr;
364 	int errcode = 0;
365 
366 	for (ptr = fmt; *ptr; ptr++) {
367 		switch (*ptr) {
368 		case 'b':{
369 				int8_t val = va_arg(ap, int);
370 				if (pdu_write(pdu, &val, sizeof(val)))
371 					errcode = -EFAULT;
372 			}
373 			break;
374 		case 'w':{
375 				__le16 val = cpu_to_le16(va_arg(ap, int));
376 				if (pdu_write(pdu, &val, sizeof(val)))
377 					errcode = -EFAULT;
378 			}
379 			break;
380 		case 'd':{
381 				__le32 val = cpu_to_le32(va_arg(ap, int32_t));
382 				if (pdu_write(pdu, &val, sizeof(val)))
383 					errcode = -EFAULT;
384 			}
385 			break;
386 		case 'q':{
387 				__le64 val = cpu_to_le64(va_arg(ap, int64_t));
388 				if (pdu_write(pdu, &val, sizeof(val)))
389 					errcode = -EFAULT;
390 			}
391 			break;
392 		case 's':{
393 				const char *sptr = va_arg(ap, const char *);
394 				uint16_t len = 0;
395 				if (sptr)
396 					len = min_t(size_t, strlen(sptr),
397 								USHRT_MAX);
398 
399 				errcode = p9pdu_writef(pdu, proto_version,
400 								"w", len);
401 				if (!errcode && pdu_write(pdu, sptr, len))
402 					errcode = -EFAULT;
403 			}
404 			break;
405 		case 'u': {
406 				kuid_t uid = va_arg(ap, kuid_t);
407 				__le32 val = cpu_to_le32(
408 						from_kuid(&init_user_ns, uid));
409 				if (pdu_write(pdu, &val, sizeof(val)))
410 					errcode = -EFAULT;
411 			} break;
412 		case 'g': {
413 				kgid_t gid = va_arg(ap, kgid_t);
414 				__le32 val = cpu_to_le32(
415 						from_kgid(&init_user_ns, gid));
416 				if (pdu_write(pdu, &val, sizeof(val)))
417 					errcode = -EFAULT;
418 			} break;
419 		case 'Q':{
420 				const struct p9_qid *qid =
421 				    va_arg(ap, const struct p9_qid *);
422 				errcode =
423 				    p9pdu_writef(pdu, proto_version, "bdq",
424 						 qid->type, qid->version,
425 						 qid->path);
426 			} break;
427 		case 'S':{
428 				const struct p9_wstat *stbuf =
429 				    va_arg(ap, const struct p9_wstat *);
430 				errcode =
431 				    p9pdu_writef(pdu, proto_version,
432 						 "wwdQdddqssss?sugu",
433 						 stbuf->size, stbuf->type,
434 						 stbuf->dev, &stbuf->qid,
435 						 stbuf->mode, stbuf->atime,
436 						 stbuf->mtime, stbuf->length,
437 						 stbuf->name, stbuf->uid,
438 						 stbuf->gid, stbuf->muid,
439 						 stbuf->extension, stbuf->n_uid,
440 						 stbuf->n_gid, stbuf->n_muid);
441 			} break;
442 		case 'V':{
443 				uint32_t count = va_arg(ap, uint32_t);
444 				struct iov_iter *from =
445 						va_arg(ap, struct iov_iter *);
446 				errcode = p9pdu_writef(pdu, proto_version, "d",
447 									count);
448 				if (!errcode && pdu_write_u(pdu, from, count))
449 					errcode = -EFAULT;
450 			}
451 			break;
452 		case 'T':{
453 				uint16_t nwname = va_arg(ap, int);
454 				const char **wnames = va_arg(ap, const char **);
455 
456 				errcode = p9pdu_writef(pdu, proto_version, "w",
457 									nwname);
458 				if (!errcode) {
459 					int i;
460 
461 					for (i = 0; i < nwname; i++) {
462 						errcode =
463 						    p9pdu_writef(pdu,
464 								proto_version,
465 								 "s",
466 								 wnames[i]);
467 						if (errcode)
468 							break;
469 					}
470 				}
471 			}
472 			break;
473 		case 'R':{
474 				uint16_t nwqid = va_arg(ap, int);
475 				struct p9_qid *wqids =
476 				    va_arg(ap, struct p9_qid *);
477 
478 				errcode = p9pdu_writef(pdu, proto_version, "w",
479 									nwqid);
480 				if (!errcode) {
481 					int i;
482 
483 					for (i = 0; i < nwqid; i++) {
484 						errcode =
485 						    p9pdu_writef(pdu,
486 								proto_version,
487 								 "Q",
488 								 &wqids[i]);
489 						if (errcode)
490 							break;
491 					}
492 				}
493 			}
494 			break;
495 		case 'I':{
496 				struct p9_iattr_dotl *p9attr = va_arg(ap,
497 							struct p9_iattr_dotl *);
498 
499 				errcode = p9pdu_writef(pdu, proto_version,
500 							"ddugqqqqq",
501 							p9attr->valid,
502 							p9attr->mode,
503 							p9attr->uid,
504 							p9attr->gid,
505 							p9attr->size,
506 							p9attr->atime_sec,
507 							p9attr->atime_nsec,
508 							p9attr->mtime_sec,
509 							p9attr->mtime_nsec);
510 			}
511 			break;
512 		case '?':
513 			if ((proto_version != p9_proto_2000u) &&
514 				(proto_version != p9_proto_2000L))
515 				return 0;
516 			break;
517 		default:
518 			BUG();
519 			break;
520 		}
521 
522 		if (errcode)
523 			break;
524 	}
525 
526 	return errcode;
527 }
528 
529 int p9pdu_readf(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
530 {
531 	va_list ap;
532 	int ret;
533 
534 	va_start(ap, fmt);
535 	ret = p9pdu_vreadf(pdu, proto_version, fmt, ap);
536 	va_end(ap);
537 
538 	return ret;
539 }
540 
541 static int
542 p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
543 {
544 	va_list ap;
545 	int ret;
546 
547 	va_start(ap, fmt);
548 	ret = p9pdu_vwritef(pdu, proto_version, fmt, ap);
549 	va_end(ap);
550 
551 	return ret;
552 }
553 
554 int p9stat_read(struct p9_client *clnt, char *buf, int len, struct p9_wstat *st)
555 {
556 	struct p9_fcall fake_pdu;
557 	int ret;
558 
559 	fake_pdu.size = len;
560 	fake_pdu.capacity = len;
561 	fake_pdu.sdata = buf;
562 	fake_pdu.offset = 0;
563 
564 	ret = p9pdu_readf(&fake_pdu, clnt->proto_version, "S", st);
565 	if (ret) {
566 		p9_debug(P9_DEBUG_9P, "<<< p9stat_read failed: %d\n", ret);
567 		trace_9p_protocol_dump(clnt, &fake_pdu);
568 	}
569 
570 	return ret;
571 }
572 EXPORT_SYMBOL(p9stat_read);
573 
574 int p9pdu_prepare(struct p9_fcall *pdu, int16_t tag, int8_t type)
575 {
576 	pdu->id = type;
577 	return p9pdu_writef(pdu, 0, "dbw", 0, type, tag);
578 }
579 
580 int p9pdu_finalize(struct p9_client *clnt, struct p9_fcall *pdu)
581 {
582 	int size = pdu->size;
583 	int err;
584 
585 	pdu->size = 0;
586 	err = p9pdu_writef(pdu, 0, "d", size);
587 	pdu->size = size;
588 
589 	trace_9p_protocol_dump(clnt, pdu);
590 	p9_debug(P9_DEBUG_9P, ">>> size=%d type: %d tag: %d\n",
591 		 pdu->size, pdu->id, pdu->tag);
592 
593 	return err;
594 }
595 
596 void p9pdu_reset(struct p9_fcall *pdu)
597 {
598 	pdu->offset = 0;
599 	pdu->size = 0;
600 }
601 
602 int p9dirent_read(struct p9_client *clnt, char *buf, int len,
603 		  struct p9_dirent *dirent)
604 {
605 	struct p9_fcall fake_pdu;
606 	int ret;
607 	char *nameptr;
608 
609 	fake_pdu.size = len;
610 	fake_pdu.capacity = len;
611 	fake_pdu.sdata = buf;
612 	fake_pdu.offset = 0;
613 
614 	ret = p9pdu_readf(&fake_pdu, clnt->proto_version, "Qqbs", &dirent->qid,
615 			  &dirent->d_off, &dirent->d_type, &nameptr);
616 	if (ret) {
617 		p9_debug(P9_DEBUG_9P, "<<< p9dirent_read failed: %d\n", ret);
618 		trace_9p_protocol_dump(clnt, &fake_pdu);
619 		goto out;
620 	}
621 
622 	strcpy(dirent->d_name, nameptr);
623 	kfree(nameptr);
624 
625 out:
626 	return fake_pdu.offset;
627 }
628 EXPORT_SYMBOL(p9dirent_read);
629