xref: /openbmc/linux/net/9p/protocol.c (revision 93f5715e) 
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_full(&pdu->sdata[pdu->size], len, &i))
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 = -ENOMEM;
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_array(*nwname,
246 							  sizeof(char *),
247 							  GFP_NOFS);
248 					if (!*wnames)
249 						errcode = -ENOMEM;
250 				}
251 
252 				if (!errcode) {
253 					int i;
254 
255 					for (i = 0; i < *nwname; i++) {
256 						errcode =
257 						    p9pdu_readf(pdu,
258 								proto_version,
259 								"s",
260 								&(*wnames)[i]);
261 						if (errcode)
262 							break;
263 					}
264 				}
265 
266 				if (errcode) {
267 					if (*wnames) {
268 						int i;
269 
270 						for (i = 0; i < *nwname; i++)
271 							kfree((*wnames)[i]);
272 					}
273 					kfree(*wnames);
274 					*wnames = NULL;
275 				}
276 			}
277 			break;
278 		case 'R':{
279 				uint16_t *nwqid = va_arg(ap, uint16_t *);
280 				struct p9_qid **wqids =
281 				    va_arg(ap, struct p9_qid **);
282 
283 				*wqids = NULL;
284 
285 				errcode =
286 				    p9pdu_readf(pdu, proto_version, "w", nwqid);
287 				if (!errcode) {
288 					*wqids =
289 					    kmalloc_array(*nwqid,
290 							  sizeof(struct p9_qid),
291 							  GFP_NOFS);
292 					if (*wqids == NULL)
293 						errcode = -ENOMEM;
294 				}
295 
296 				if (!errcode) {
297 					int i;
298 
299 					for (i = 0; i < *nwqid; i++) {
300 						errcode =
301 						    p9pdu_readf(pdu,
302 								proto_version,
303 								"Q",
304 								&(*wqids)[i]);
305 						if (errcode)
306 							break;
307 					}
308 				}
309 
310 				if (errcode) {
311 					kfree(*wqids);
312 					*wqids = NULL;
313 				}
314 			}
315 			break;
316 		case 'A': {
317 				struct p9_stat_dotl *stbuf =
318 				    va_arg(ap, struct p9_stat_dotl *);
319 
320 				memset(stbuf, 0, sizeof(struct p9_stat_dotl));
321 				errcode =
322 				    p9pdu_readf(pdu, proto_version,
323 					"qQdugqqqqqqqqqqqqqqq",
324 					&stbuf->st_result_mask,
325 					&stbuf->qid,
326 					&stbuf->st_mode,
327 					&stbuf->st_uid, &stbuf->st_gid,
328 					&stbuf->st_nlink,
329 					&stbuf->st_rdev, &stbuf->st_size,
330 					&stbuf->st_blksize, &stbuf->st_blocks,
331 					&stbuf->st_atime_sec,
332 					&stbuf->st_atime_nsec,
333 					&stbuf->st_mtime_sec,
334 					&stbuf->st_mtime_nsec,
335 					&stbuf->st_ctime_sec,
336 					&stbuf->st_ctime_nsec,
337 					&stbuf->st_btime_sec,
338 					&stbuf->st_btime_nsec,
339 					&stbuf->st_gen,
340 					&stbuf->st_data_version);
341 			}
342 			break;
343 		case '?':
344 			if ((proto_version != p9_proto_2000u) &&
345 				(proto_version != p9_proto_2000L))
346 				return 0;
347 			break;
348 		default:
349 			BUG();
350 			break;
351 		}
352 
353 		if (errcode)
354 			break;
355 	}
356 
357 	return errcode;
358 }
359 
360 int
361 p9pdu_vwritef(struct p9_fcall *pdu, int proto_version, const char *fmt,
362 	va_list ap)
363 {
364 	const char *ptr;
365 	int errcode = 0;
366 
367 	for (ptr = fmt; *ptr; ptr++) {
368 		switch (*ptr) {
369 		case 'b':{
370 				int8_t val = va_arg(ap, int);
371 				if (pdu_write(pdu, &val, sizeof(val)))
372 					errcode = -EFAULT;
373 			}
374 			break;
375 		case 'w':{
376 				__le16 val = cpu_to_le16(va_arg(ap, int));
377 				if (pdu_write(pdu, &val, sizeof(val)))
378 					errcode = -EFAULT;
379 			}
380 			break;
381 		case 'd':{
382 				__le32 val = cpu_to_le32(va_arg(ap, int32_t));
383 				if (pdu_write(pdu, &val, sizeof(val)))
384 					errcode = -EFAULT;
385 			}
386 			break;
387 		case 'q':{
388 				__le64 val = cpu_to_le64(va_arg(ap, int64_t));
389 				if (pdu_write(pdu, &val, sizeof(val)))
390 					errcode = -EFAULT;
391 			}
392 			break;
393 		case 's':{
394 				const char *sptr = va_arg(ap, const char *);
395 				uint16_t len = 0;
396 				if (sptr)
397 					len = min_t(size_t, strlen(sptr),
398 								USHRT_MAX);
399 
400 				errcode = p9pdu_writef(pdu, proto_version,
401 								"w", len);
402 				if (!errcode && pdu_write(pdu, sptr, len))
403 					errcode = -EFAULT;
404 			}
405 			break;
406 		case 'u': {
407 				kuid_t uid = va_arg(ap, kuid_t);
408 				__le32 val = cpu_to_le32(
409 						from_kuid(&init_user_ns, uid));
410 				if (pdu_write(pdu, &val, sizeof(val)))
411 					errcode = -EFAULT;
412 			} break;
413 		case 'g': {
414 				kgid_t gid = va_arg(ap, kgid_t);
415 				__le32 val = cpu_to_le32(
416 						from_kgid(&init_user_ns, gid));
417 				if (pdu_write(pdu, &val, sizeof(val)))
418 					errcode = -EFAULT;
419 			} break;
420 		case 'Q':{
421 				const struct p9_qid *qid =
422 				    va_arg(ap, const struct p9_qid *);
423 				errcode =
424 				    p9pdu_writef(pdu, proto_version, "bdq",
425 						 qid->type, qid->version,
426 						 qid->path);
427 			} break;
428 		case 'S':{
429 				const struct p9_wstat *stbuf =
430 				    va_arg(ap, const struct p9_wstat *);
431 				errcode =
432 				    p9pdu_writef(pdu, proto_version,
433 						 "wwdQdddqssss?sugu",
434 						 stbuf->size, stbuf->type,
435 						 stbuf->dev, &stbuf->qid,
436 						 stbuf->mode, stbuf->atime,
437 						 stbuf->mtime, stbuf->length,
438 						 stbuf->name, stbuf->uid,
439 						 stbuf->gid, stbuf->muid,
440 						 stbuf->extension, stbuf->n_uid,
441 						 stbuf->n_gid, stbuf->n_muid);
442 			} break;
443 		case 'V':{
444 				uint32_t count = va_arg(ap, uint32_t);
445 				struct iov_iter *from =
446 						va_arg(ap, struct iov_iter *);
447 				errcode = p9pdu_writef(pdu, proto_version, "d",
448 									count);
449 				if (!errcode && pdu_write_u(pdu, from, count))
450 					errcode = -EFAULT;
451 			}
452 			break;
453 		case 'T':{
454 				uint16_t nwname = va_arg(ap, int);
455 				const char **wnames = va_arg(ap, const char **);
456 
457 				errcode = p9pdu_writef(pdu, proto_version, "w",
458 									nwname);
459 				if (!errcode) {
460 					int i;
461 
462 					for (i = 0; i < nwname; i++) {
463 						errcode =
464 						    p9pdu_writef(pdu,
465 								proto_version,
466 								 "s",
467 								 wnames[i]);
468 						if (errcode)
469 							break;
470 					}
471 				}
472 			}
473 			break;
474 		case 'R':{
475 				uint16_t nwqid = va_arg(ap, int);
476 				struct p9_qid *wqids =
477 				    va_arg(ap, struct p9_qid *);
478 
479 				errcode = p9pdu_writef(pdu, proto_version, "w",
480 									nwqid);
481 				if (!errcode) {
482 					int i;
483 
484 					for (i = 0; i < nwqid; i++) {
485 						errcode =
486 						    p9pdu_writef(pdu,
487 								proto_version,
488 								 "Q",
489 								 &wqids[i]);
490 						if (errcode)
491 							break;
492 					}
493 				}
494 			}
495 			break;
496 		case 'I':{
497 				struct p9_iattr_dotl *p9attr = va_arg(ap,
498 							struct p9_iattr_dotl *);
499 
500 				errcode = p9pdu_writef(pdu, proto_version,
501 							"ddugqqqqq",
502 							p9attr->valid,
503 							p9attr->mode,
504 							p9attr->uid,
505 							p9attr->gid,
506 							p9attr->size,
507 							p9attr->atime_sec,
508 							p9attr->atime_nsec,
509 							p9attr->mtime_sec,
510 							p9attr->mtime_nsec);
511 			}
512 			break;
513 		case '?':
514 			if ((proto_version != p9_proto_2000u) &&
515 				(proto_version != p9_proto_2000L))
516 				return 0;
517 			break;
518 		default:
519 			BUG();
520 			break;
521 		}
522 
523 		if (errcode)
524 			break;
525 	}
526 
527 	return errcode;
528 }
529 
530 int p9pdu_readf(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
531 {
532 	va_list ap;
533 	int ret;
534 
535 	va_start(ap, fmt);
536 	ret = p9pdu_vreadf(pdu, proto_version, fmt, ap);
537 	va_end(ap);
538 
539 	return ret;
540 }
541 
542 static int
543 p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
544 {
545 	va_list ap;
546 	int ret;
547 
548 	va_start(ap, fmt);
549 	ret = p9pdu_vwritef(pdu, proto_version, fmt, ap);
550 	va_end(ap);
551 
552 	return ret;
553 }
554 
555 int p9stat_read(struct p9_client *clnt, char *buf, int len, struct p9_wstat *st)
556 {
557 	struct p9_fcall fake_pdu;
558 	int ret;
559 
560 	fake_pdu.size = len;
561 	fake_pdu.capacity = len;
562 	fake_pdu.sdata = buf;
563 	fake_pdu.offset = 0;
564 
565 	ret = p9pdu_readf(&fake_pdu, clnt->proto_version, "S", st);
566 	if (ret) {
567 		p9_debug(P9_DEBUG_9P, "<<< p9stat_read failed: %d\n", ret);
568 		trace_9p_protocol_dump(clnt, &fake_pdu);
569 	}
570 
571 	return ret;
572 }
573 EXPORT_SYMBOL(p9stat_read);
574 
575 int p9pdu_prepare(struct p9_fcall *pdu, int16_t tag, int8_t type)
576 {
577 	pdu->id = type;
578 	return p9pdu_writef(pdu, 0, "dbw", 0, type, tag);
579 }
580 
581 int p9pdu_finalize(struct p9_client *clnt, struct p9_fcall *pdu)
582 {
583 	int size = pdu->size;
584 	int err;
585 
586 	pdu->size = 0;
587 	err = p9pdu_writef(pdu, 0, "d", size);
588 	pdu->size = size;
589 
590 	trace_9p_protocol_dump(clnt, pdu);
591 	p9_debug(P9_DEBUG_9P, ">>> size=%d type: %d tag: %d\n",
592 		 pdu->size, pdu->id, pdu->tag);
593 
594 	return err;
595 }
596 
597 void p9pdu_reset(struct p9_fcall *pdu)
598 {
599 	pdu->offset = 0;
600 	pdu->size = 0;
601 }
602 
603 int p9dirent_read(struct p9_client *clnt, char *buf, int len,
604 		  struct p9_dirent *dirent)
605 {
606 	struct p9_fcall fake_pdu;
607 	int ret;
608 	char *nameptr;
609 
610 	fake_pdu.size = len;
611 	fake_pdu.capacity = len;
612 	fake_pdu.sdata = buf;
613 	fake_pdu.offset = 0;
614 
615 	ret = p9pdu_readf(&fake_pdu, clnt->proto_version, "Qqbs", &dirent->qid,
616 			  &dirent->d_off, &dirent->d_type, &nameptr);
617 	if (ret) {
618 		p9_debug(P9_DEBUG_9P, "<<< p9dirent_read failed: %d\n", ret);
619 		trace_9p_protocol_dump(clnt, &fake_pdu);
620 		goto out;
621 	}
622 
623 	strcpy(dirent->d_name, nameptr);
624 	kfree(nameptr);
625 
626 out:
627 	return fake_pdu.offset;
628 }
629 EXPORT_SYMBOL(p9dirent_read);
630