xref: /openbmc/linux/net/9p/protocol.c (revision 81d67439) 
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 static int
41 p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...);
42 
43 #ifdef CONFIG_NET_9P_DEBUG
44 void
45 p9pdu_dump(int way, struct p9_fcall *pdu)
46 {
47 	int len = pdu->size;
48 
49 	if ((p9_debug_level & P9_DEBUG_VPKT) != P9_DEBUG_VPKT) {
50 		if ((p9_debug_level & P9_DEBUG_PKT) == P9_DEBUG_PKT) {
51 			if (len > 32)
52 				len = 32;
53 		} else {
54 			/* shouldn't happen */
55 			return;
56 		}
57 	}
58 
59 	if (way)
60 		print_hex_dump_bytes("[9P] ", DUMP_PREFIX_OFFSET, pdu->sdata,
61 									len);
62 	else
63 		print_hex_dump_bytes("]9P[ ", DUMP_PREFIX_OFFSET, pdu->sdata,
64 									len);
65 }
66 #else
67 void
68 p9pdu_dump(int way, struct p9_fcall *pdu)
69 {
70 }
71 #endif
72 EXPORT_SYMBOL(p9pdu_dump);
73 
74 void p9stat_free(struct p9_wstat *stbuf)
75 {
76 	kfree(stbuf->name);
77 	kfree(stbuf->uid);
78 	kfree(stbuf->gid);
79 	kfree(stbuf->muid);
80 	kfree(stbuf->extension);
81 }
82 EXPORT_SYMBOL(p9stat_free);
83 
84 static size_t pdu_read(struct p9_fcall *pdu, void *data, size_t size)
85 {
86 	size_t len = min(pdu->size - pdu->offset, size);
87 	memcpy(data, &pdu->sdata[pdu->offset], len);
88 	pdu->offset += len;
89 	return size - len;
90 }
91 
92 static size_t pdu_write(struct p9_fcall *pdu, const void *data, size_t size)
93 {
94 	size_t len = min(pdu->capacity - pdu->size, size);
95 	memcpy(&pdu->sdata[pdu->size], data, len);
96 	pdu->size += len;
97 	return size - len;
98 }
99 
100 static size_t
101 pdu_write_u(struct p9_fcall *pdu, const char __user *udata, size_t size)
102 {
103 	size_t len = min(pdu->capacity - pdu->size, size);
104 	if (copy_from_user(&pdu->sdata[pdu->size], udata, len))
105 		len = 0;
106 
107 	pdu->size += len;
108 	return size - len;
109 }
110 
111 static size_t
112 pdu_write_urw(struct p9_fcall *pdu, const char *kdata, const char __user *udata,
113 		size_t size)
114 {
115 	BUG_ON(pdu->size > P9_IOHDRSZ);
116 	pdu->pubuf = (char __user *)udata;
117 	pdu->pkbuf = (char *)kdata;
118 	pdu->pbuf_size = size;
119 	return 0;
120 }
121 
122 static size_t
123 pdu_write_readdir(struct p9_fcall *pdu, const char *kdata, size_t size)
124 {
125 	BUG_ON(pdu->size > P9_READDIRHDRSZ);
126 	pdu->pkbuf = (char *)kdata;
127 	pdu->pbuf_size = size;
128 	return 0;
129 }
130 
131 /*
132 	b - int8_t
133 	w - int16_t
134 	d - int32_t
135 	q - int64_t
136 	s - string
137 	S - stat
138 	Q - qid
139 	D - data blob (int32_t size followed by void *, results are not freed)
140 	T - array of strings (int16_t count, followed by strings)
141 	R - array of qids (int16_t count, followed by qids)
142 	A - stat for 9p2000.L (p9_stat_dotl)
143 	? - if optional = 1, continue parsing
144 */
145 
146 static int
147 p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt,
148 	va_list ap)
149 {
150 	const char *ptr;
151 	int errcode = 0;
152 
153 	for (ptr = fmt; *ptr; ptr++) {
154 		switch (*ptr) {
155 		case 'b':{
156 				int8_t *val = va_arg(ap, int8_t *);
157 				if (pdu_read(pdu, val, sizeof(*val))) {
158 					errcode = -EFAULT;
159 					break;
160 				}
161 			}
162 			break;
163 		case 'w':{
164 				int16_t *val = va_arg(ap, int16_t *);
165 				__le16 le_val;
166 				if (pdu_read(pdu, &le_val, sizeof(le_val))) {
167 					errcode = -EFAULT;
168 					break;
169 				}
170 				*val = le16_to_cpu(le_val);
171 			}
172 			break;
173 		case 'd':{
174 				int32_t *val = va_arg(ap, int32_t *);
175 				__le32 le_val;
176 				if (pdu_read(pdu, &le_val, sizeof(le_val))) {
177 					errcode = -EFAULT;
178 					break;
179 				}
180 				*val = le32_to_cpu(le_val);
181 			}
182 			break;
183 		case 'q':{
184 				int64_t *val = va_arg(ap, int64_t *);
185 				__le64 le_val;
186 				if (pdu_read(pdu, &le_val, sizeof(le_val))) {
187 					errcode = -EFAULT;
188 					break;
189 				}
190 				*val = le64_to_cpu(le_val);
191 			}
192 			break;
193 		case 's':{
194 				char **sptr = va_arg(ap, char **);
195 				uint16_t len;
196 
197 				errcode = p9pdu_readf(pdu, proto_version,
198 								"w", &len);
199 				if (errcode)
200 					break;
201 
202 				*sptr = kmalloc(len + 1, GFP_NOFS);
203 				if (*sptr == NULL) {
204 					errcode = -EFAULT;
205 					break;
206 				}
207 				if (pdu_read(pdu, *sptr, len)) {
208 					errcode = -EFAULT;
209 					kfree(*sptr);
210 					*sptr = NULL;
211 				} else
212 					(*sptr)[len] = 0;
213 			}
214 			break;
215 		case 'Q':{
216 				struct p9_qid *qid =
217 				    va_arg(ap, struct p9_qid *);
218 
219 				errcode = p9pdu_readf(pdu, proto_version, "bdq",
220 						      &qid->type, &qid->version,
221 						      &qid->path);
222 			}
223 			break;
224 		case 'S':{
225 				struct p9_wstat *stbuf =
226 				    va_arg(ap, struct p9_wstat *);
227 
228 				memset(stbuf, 0, sizeof(struct p9_wstat));
229 				stbuf->n_uid = stbuf->n_gid = stbuf->n_muid =
230 									-1;
231 				errcode =
232 				    p9pdu_readf(pdu, proto_version,
233 						"wwdQdddqssss?sddd",
234 						&stbuf->size, &stbuf->type,
235 						&stbuf->dev, &stbuf->qid,
236 						&stbuf->mode, &stbuf->atime,
237 						&stbuf->mtime, &stbuf->length,
238 						&stbuf->name, &stbuf->uid,
239 						&stbuf->gid, &stbuf->muid,
240 						&stbuf->extension,
241 						&stbuf->n_uid, &stbuf->n_gid,
242 						&stbuf->n_muid);
243 				if (errcode)
244 					p9stat_free(stbuf);
245 			}
246 			break;
247 		case 'D':{
248 				uint32_t *count = va_arg(ap, uint32_t *);
249 				void **data = va_arg(ap, void **);
250 
251 				errcode =
252 				    p9pdu_readf(pdu, proto_version, "d", count);
253 				if (!errcode) {
254 					*count =
255 					    min_t(uint32_t, *count,
256 						  pdu->size - pdu->offset);
257 					*data = &pdu->sdata[pdu->offset];
258 				}
259 			}
260 			break;
261 		case 'T':{
262 				uint16_t *nwname = va_arg(ap, uint16_t *);
263 				char ***wnames = va_arg(ap, char ***);
264 
265 				errcode = p9pdu_readf(pdu, proto_version,
266 								"w", nwname);
267 				if (!errcode) {
268 					*wnames =
269 					    kmalloc(sizeof(char *) * *nwname,
270 						    GFP_NOFS);
271 					if (!*wnames)
272 						errcode = -ENOMEM;
273 				}
274 
275 				if (!errcode) {
276 					int i;
277 
278 					for (i = 0; i < *nwname; i++) {
279 						errcode =
280 						    p9pdu_readf(pdu,
281 								proto_version,
282 								"s",
283 								&(*wnames)[i]);
284 						if (errcode)
285 							break;
286 					}
287 				}
288 
289 				if (errcode) {
290 					if (*wnames) {
291 						int i;
292 
293 						for (i = 0; i < *nwname; i++)
294 							kfree((*wnames)[i]);
295 					}
296 					kfree(*wnames);
297 					*wnames = NULL;
298 				}
299 			}
300 			break;
301 		case 'R':{
302 				int16_t *nwqid = va_arg(ap, int16_t *);
303 				struct p9_qid **wqids =
304 				    va_arg(ap, struct p9_qid **);
305 
306 				*wqids = NULL;
307 
308 				errcode =
309 				    p9pdu_readf(pdu, proto_version, "w", nwqid);
310 				if (!errcode) {
311 					*wqids =
312 					    kmalloc(*nwqid *
313 						    sizeof(struct p9_qid),
314 						    GFP_NOFS);
315 					if (*wqids == NULL)
316 						errcode = -ENOMEM;
317 				}
318 
319 				if (!errcode) {
320 					int i;
321 
322 					for (i = 0; i < *nwqid; i++) {
323 						errcode =
324 						    p9pdu_readf(pdu,
325 								proto_version,
326 								"Q",
327 								&(*wqids)[i]);
328 						if (errcode)
329 							break;
330 					}
331 				}
332 
333 				if (errcode) {
334 					kfree(*wqids);
335 					*wqids = NULL;
336 				}
337 			}
338 			break;
339 		case 'A': {
340 				struct p9_stat_dotl *stbuf =
341 				    va_arg(ap, struct p9_stat_dotl *);
342 
343 				memset(stbuf, 0, sizeof(struct p9_stat_dotl));
344 				errcode =
345 				    p9pdu_readf(pdu, proto_version,
346 					"qQdddqqqqqqqqqqqqqqq",
347 					&stbuf->st_result_mask,
348 					&stbuf->qid,
349 					&stbuf->st_mode,
350 					&stbuf->st_uid, &stbuf->st_gid,
351 					&stbuf->st_nlink,
352 					&stbuf->st_rdev, &stbuf->st_size,
353 					&stbuf->st_blksize, &stbuf->st_blocks,
354 					&stbuf->st_atime_sec,
355 					&stbuf->st_atime_nsec,
356 					&stbuf->st_mtime_sec,
357 					&stbuf->st_mtime_nsec,
358 					&stbuf->st_ctime_sec,
359 					&stbuf->st_ctime_nsec,
360 					&stbuf->st_btime_sec,
361 					&stbuf->st_btime_nsec,
362 					&stbuf->st_gen,
363 					&stbuf->st_data_version);
364 			}
365 			break;
366 		case '?':
367 			if ((proto_version != p9_proto_2000u) &&
368 				(proto_version != p9_proto_2000L))
369 				return 0;
370 			break;
371 		default:
372 			BUG();
373 			break;
374 		}
375 
376 		if (errcode)
377 			break;
378 	}
379 
380 	return errcode;
381 }
382 
383 int
384 p9pdu_vwritef(struct p9_fcall *pdu, int proto_version, const char *fmt,
385 	va_list ap)
386 {
387 	const char *ptr;
388 	int errcode = 0;
389 
390 	for (ptr = fmt; *ptr; ptr++) {
391 		switch (*ptr) {
392 		case 'b':{
393 				int8_t val = va_arg(ap, int);
394 				if (pdu_write(pdu, &val, sizeof(val)))
395 					errcode = -EFAULT;
396 			}
397 			break;
398 		case 'w':{
399 				__le16 val = cpu_to_le16(va_arg(ap, int));
400 				if (pdu_write(pdu, &val, sizeof(val)))
401 					errcode = -EFAULT;
402 			}
403 			break;
404 		case 'd':{
405 				__le32 val = cpu_to_le32(va_arg(ap, int32_t));
406 				if (pdu_write(pdu, &val, sizeof(val)))
407 					errcode = -EFAULT;
408 			}
409 			break;
410 		case 'q':{
411 				__le64 val = cpu_to_le64(va_arg(ap, int64_t));
412 				if (pdu_write(pdu, &val, sizeof(val)))
413 					errcode = -EFAULT;
414 			}
415 			break;
416 		case 's':{
417 				const char *sptr = va_arg(ap, const char *);
418 				uint16_t len = 0;
419 				if (sptr)
420 					len = min_t(uint16_t, strlen(sptr),
421 								USHRT_MAX);
422 
423 				errcode = p9pdu_writef(pdu, proto_version,
424 								"w", len);
425 				if (!errcode && pdu_write(pdu, sptr, len))
426 					errcode = -EFAULT;
427 			}
428 			break;
429 		case 'Q':{
430 				const struct p9_qid *qid =
431 				    va_arg(ap, const struct p9_qid *);
432 				errcode =
433 				    p9pdu_writef(pdu, proto_version, "bdq",
434 						 qid->type, qid->version,
435 						 qid->path);
436 			} break;
437 		case 'S':{
438 				const struct p9_wstat *stbuf =
439 				    va_arg(ap, const struct p9_wstat *);
440 				errcode =
441 				    p9pdu_writef(pdu, proto_version,
442 						 "wwdQdddqssss?sddd",
443 						 stbuf->size, stbuf->type,
444 						 stbuf->dev, &stbuf->qid,
445 						 stbuf->mode, stbuf->atime,
446 						 stbuf->mtime, stbuf->length,
447 						 stbuf->name, stbuf->uid,
448 						 stbuf->gid, stbuf->muid,
449 						 stbuf->extension, stbuf->n_uid,
450 						 stbuf->n_gid, stbuf->n_muid);
451 			} break;
452 		case 'D':{
453 				uint32_t count = va_arg(ap, uint32_t);
454 				const void *data = va_arg(ap, const void *);
455 
456 				errcode = p9pdu_writef(pdu, proto_version, "d",
457 									count);
458 				if (!errcode && pdu_write(pdu, data, count))
459 					errcode = -EFAULT;
460 			}
461 			break;
462 		case 'E':{
463 				 int32_t cnt = va_arg(ap, int32_t);
464 				 const char *k = va_arg(ap, const void *);
465 				 const char __user *u = va_arg(ap,
466 							const void __user *);
467 				 errcode = p9pdu_writef(pdu, proto_version, "d",
468 						 cnt);
469 				 if (!errcode && pdu_write_urw(pdu, k, u, cnt))
470 					errcode = -EFAULT;
471 			 }
472 			 break;
473 		case 'F':{
474 				 int32_t cnt = va_arg(ap, int32_t);
475 				 const char *k = va_arg(ap, const void *);
476 				 errcode = p9pdu_writef(pdu, proto_version, "d",
477 						 cnt);
478 				 if (!errcode && pdu_write_readdir(pdu, k, cnt))
479 					errcode = -EFAULT;
480 			 }
481 			 break;
482 		case 'U':{
483 				int32_t count = va_arg(ap, int32_t);
484 				const char __user *udata =
485 						va_arg(ap, const void __user *);
486 				errcode = p9pdu_writef(pdu, proto_version, "d",
487 									count);
488 				if (!errcode && pdu_write_u(pdu, udata, count))
489 					errcode = -EFAULT;
490 			}
491 			break;
492 		case 'T':{
493 				uint16_t nwname = va_arg(ap, int);
494 				const char **wnames = va_arg(ap, const char **);
495 
496 				errcode = p9pdu_writef(pdu, proto_version, "w",
497 									nwname);
498 				if (!errcode) {
499 					int i;
500 
501 					for (i = 0; i < nwname; i++) {
502 						errcode =
503 						    p9pdu_writef(pdu,
504 								proto_version,
505 								 "s",
506 								 wnames[i]);
507 						if (errcode)
508 							break;
509 					}
510 				}
511 			}
512 			break;
513 		case 'R':{
514 				int16_t nwqid = va_arg(ap, int);
515 				struct p9_qid *wqids =
516 				    va_arg(ap, struct p9_qid *);
517 
518 				errcode = p9pdu_writef(pdu, proto_version, "w",
519 									nwqid);
520 				if (!errcode) {
521 					int i;
522 
523 					for (i = 0; i < nwqid; i++) {
524 						errcode =
525 						    p9pdu_writef(pdu,
526 								proto_version,
527 								 "Q",
528 								 &wqids[i]);
529 						if (errcode)
530 							break;
531 					}
532 				}
533 			}
534 			break;
535 		case 'I':{
536 				struct p9_iattr_dotl *p9attr = va_arg(ap,
537 							struct p9_iattr_dotl *);
538 
539 				errcode = p9pdu_writef(pdu, proto_version,
540 							"ddddqqqqq",
541 							p9attr->valid,
542 							p9attr->mode,
543 							p9attr->uid,
544 							p9attr->gid,
545 							p9attr->size,
546 							p9attr->atime_sec,
547 							p9attr->atime_nsec,
548 							p9attr->mtime_sec,
549 							p9attr->mtime_nsec);
550 			}
551 			break;
552 		case '?':
553 			if ((proto_version != p9_proto_2000u) &&
554 				(proto_version != p9_proto_2000L))
555 				return 0;
556 			break;
557 		default:
558 			BUG();
559 			break;
560 		}
561 
562 		if (errcode)
563 			break;
564 	}
565 
566 	return errcode;
567 }
568 
569 int p9pdu_readf(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
570 {
571 	va_list ap;
572 	int ret;
573 
574 	va_start(ap, fmt);
575 	ret = p9pdu_vreadf(pdu, proto_version, fmt, ap);
576 	va_end(ap);
577 
578 	return ret;
579 }
580 
581 static int
582 p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
583 {
584 	va_list ap;
585 	int ret;
586 
587 	va_start(ap, fmt);
588 	ret = p9pdu_vwritef(pdu, proto_version, fmt, ap);
589 	va_end(ap);
590 
591 	return ret;
592 }
593 
594 int p9stat_read(char *buf, int len, struct p9_wstat *st, int proto_version)
595 {
596 	struct p9_fcall fake_pdu;
597 	int ret;
598 
599 	fake_pdu.size = len;
600 	fake_pdu.capacity = len;
601 	fake_pdu.sdata = buf;
602 	fake_pdu.offset = 0;
603 
604 	ret = p9pdu_readf(&fake_pdu, proto_version, "S", st);
605 	if (ret) {
606 		P9_DPRINTK(P9_DEBUG_9P, "<<< p9stat_read failed: %d\n", ret);
607 		P9_DUMP_PKT(0, &fake_pdu);
608 	}
609 
610 	return ret;
611 }
612 EXPORT_SYMBOL(p9stat_read);
613 
614 int p9pdu_prepare(struct p9_fcall *pdu, int16_t tag, int8_t type)
615 {
616 	pdu->id = type;
617 	return p9pdu_writef(pdu, 0, "dbw", 0, type, tag);
618 }
619 
620 int p9pdu_finalize(struct p9_fcall *pdu)
621 {
622 	int size = pdu->size;
623 	int err;
624 
625 	pdu->size = 0;
626 	err = p9pdu_writef(pdu, 0, "d", size);
627 	pdu->size = size;
628 
629 	P9_DUMP_PKT(0, pdu);
630 	P9_DPRINTK(P9_DEBUG_9P, ">>> size=%d type: %d tag: %d\n", pdu->size,
631 							pdu->id, pdu->tag);
632 
633 	return err;
634 }
635 
636 void p9pdu_reset(struct p9_fcall *pdu)
637 {
638 	pdu->offset = 0;
639 	pdu->size = 0;
640 	pdu->private = NULL;
641 	pdu->pubuf = NULL;
642 	pdu->pkbuf = NULL;
643 	pdu->pbuf_size = 0;
644 }
645 
646 int p9dirent_read(char *buf, int len, struct p9_dirent *dirent,
647 						int proto_version)
648 {
649 	struct p9_fcall fake_pdu;
650 	int ret;
651 	char *nameptr;
652 
653 	fake_pdu.size = len;
654 	fake_pdu.capacity = len;
655 	fake_pdu.sdata = buf;
656 	fake_pdu.offset = 0;
657 
658 	ret = p9pdu_readf(&fake_pdu, proto_version, "Qqbs", &dirent->qid,
659 			&dirent->d_off, &dirent->d_type, &nameptr);
660 	if (ret) {
661 		P9_DPRINTK(P9_DEBUG_9P, "<<< p9dirent_read failed: %d\n", ret);
662 		P9_DUMP_PKT(1, &fake_pdu);
663 		goto out;
664 	}
665 
666 	strcpy(dirent->d_name, nameptr);
667 	kfree(nameptr);
668 
669 out:
670 	return fake_pdu.offset;
671 }
672 EXPORT_SYMBOL(p9dirent_read);
673