xref: /linux/net/9p/protocol.c (revision 930cc144a043ff95e56b6888fa51c618b33f89e7) 
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/uaccess.h>
31 #include <linux/sched.h>
32 #include <net/9p/9p.h>
33 #include <net/9p/client.h>
34 #include "protocol.h"
35 
36 #ifndef MIN
37 #define MIN(a, b) (((a) < (b)) ? (a) : (b))
38 #endif
39 
40 #ifndef MAX
41 #define MAX(a, b) (((a) > (b)) ? (a) : (b))
42 #endif
43 
44 #ifndef offset_of
45 #define offset_of(type, memb) \
46 	((unsigned long)(&((type *)0)->memb))
47 #endif
48 #ifndef container_of
49 #define container_of(obj, type, memb) \
50 	((type *)(((char *)obj) - offset_of(type, memb)))
51 #endif
52 
53 static int
54 p9pdu_writef(struct p9_fcall *pdu, int optional, const char *fmt, ...);
55 
56 void
57 p9pdu_dump(int way, struct p9_fcall *pdu)
58 {
59 	int i, n;
60 	u8 *data = pdu->sdata;
61 	int datalen = pdu->size;
62 	char buf[255];
63 	int buflen = 255;
64 
65 	i = n = 0;
66 	if (datalen > (buflen-16))
67 		datalen = buflen-16;
68 	while (i < datalen) {
69 		n += scnprintf(buf + n, buflen - n, "%02x ", data[i]);
70 		if (i%4 == 3)
71 			n += scnprintf(buf + n, buflen - n, " ");
72 		if (i%32 == 31)
73 			n += scnprintf(buf + n, buflen - n, "\n");
74 
75 		i++;
76 	}
77 	n += scnprintf(buf + n, buflen - n, "\n");
78 
79 	if (way)
80 		P9_DPRINTK(P9_DEBUG_PKT, "[[[(%d) %s\n", datalen, buf);
81 	else
82 		P9_DPRINTK(P9_DEBUG_PKT, "]]](%d) %s\n", datalen, buf);
83 }
84 EXPORT_SYMBOL(p9pdu_dump);
85 
86 void p9stat_free(struct p9_wstat *stbuf)
87 {
88 	kfree(stbuf->name);
89 	kfree(stbuf->uid);
90 	kfree(stbuf->gid);
91 	kfree(stbuf->muid);
92 	kfree(stbuf->extension);
93 }
94 EXPORT_SYMBOL(p9stat_free);
95 
96 static size_t pdu_read(struct p9_fcall *pdu, void *data, size_t size)
97 {
98 	size_t len = MIN(pdu->size - pdu->offset, size);
99 	memcpy(data, &pdu->sdata[pdu->offset], len);
100 	pdu->offset += len;
101 	return size - len;
102 }
103 
104 static size_t pdu_write(struct p9_fcall *pdu, const void *data, size_t size)
105 {
106 	size_t len = MIN(pdu->capacity - pdu->size, size);
107 	memcpy(&pdu->sdata[pdu->size], data, len);
108 	pdu->size += len;
109 	return size - len;
110 }
111 
112 static size_t
113 pdu_write_u(struct p9_fcall *pdu, const char __user *udata, size_t size)
114 {
115 	size_t len = MIN(pdu->capacity - pdu->size, size);
116 	int err = copy_from_user(&pdu->sdata[pdu->size], udata, len);
117 	if (err)
118 		printk(KERN_WARNING "pdu_write_u returning: %d\n", err);
119 
120 	pdu->size += len;
121 	return size - len;
122 }
123 
124 /*
125 	b - int8_t
126 	w - int16_t
127 	d - int32_t
128 	q - int64_t
129 	s - string
130 	S - stat
131 	Q - qid
132 	D - data blob (int32_t size followed by void *, results are not freed)
133 	T - array of strings (int16_t count, followed by strings)
134 	R - array of qids (int16_t count, followed by qids)
135 	? - if optional = 1, continue parsing
136 */
137 
138 static int
139 p9pdu_vreadf(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
140 {
141 	const char *ptr;
142 	int errcode = 0;
143 
144 	for (ptr = fmt; *ptr; ptr++) {
145 		switch (*ptr) {
146 		case 'b':{
147 				int8_t *val = va_arg(ap, int8_t *);
148 				if (pdu_read(pdu, val, sizeof(*val))) {
149 					errcode = -EFAULT;
150 					break;
151 				}
152 			}
153 			break;
154 		case 'w':{
155 				int16_t *val = va_arg(ap, int16_t *);
156 				if (pdu_read(pdu, val, sizeof(*val))) {
157 					errcode = -EFAULT;
158 					break;
159 				}
160 				*val = cpu_to_le16(*val);
161 			}
162 			break;
163 		case 'd':{
164 				int32_t *val = va_arg(ap, int32_t *);
165 				if (pdu_read(pdu, val, sizeof(*val))) {
166 					errcode = -EFAULT;
167 					break;
168 				}
169 				*val = cpu_to_le32(*val);
170 			}
171 			break;
172 		case 'q':{
173 				int64_t *val = va_arg(ap, int64_t *);
174 				if (pdu_read(pdu, val, sizeof(*val))) {
175 					errcode = -EFAULT;
176 					break;
177 				}
178 				*val = cpu_to_le64(*val);
179 			}
180 			break;
181 		case 's':{
182 				char **ptr = va_arg(ap, char **);
183 				int16_t len;
184 				int size;
185 
186 				errcode = p9pdu_readf(pdu, optional, "w", &len);
187 				if (errcode)
188 					break;
189 
190 				size = MAX(len, 0);
191 
192 				*ptr = kmalloc(size + 1, GFP_KERNEL);
193 				if (*ptr == NULL) {
194 					errcode = -EFAULT;
195 					break;
196 				}
197 				if (pdu_read(pdu, *ptr, size)) {
198 					errcode = -EFAULT;
199 					kfree(*ptr);
200 					*ptr = NULL;
201 				} else
202 					(*ptr)[size] = 0;
203 			}
204 			break;
205 		case 'Q':{
206 				struct p9_qid *qid =
207 				    va_arg(ap, struct p9_qid *);
208 
209 				errcode = p9pdu_readf(pdu, optional, "bdq",
210 						      &qid->type, &qid->version,
211 						      &qid->path);
212 			}
213 			break;
214 		case 'S':{
215 				struct p9_wstat *stbuf =
216 				    va_arg(ap, struct p9_wstat *);
217 
218 				memset(stbuf, 0, sizeof(struct p9_wstat));
219 				stbuf->n_uid = stbuf->n_gid = stbuf->n_muid =
220 									-1;
221 				errcode =
222 				    p9pdu_readf(pdu, optional,
223 						"wwdQdddqssss?sddd",
224 						&stbuf->size, &stbuf->type,
225 						&stbuf->dev, &stbuf->qid,
226 						&stbuf->mode, &stbuf->atime,
227 						&stbuf->mtime, &stbuf->length,
228 						&stbuf->name, &stbuf->uid,
229 						&stbuf->gid, &stbuf->muid,
230 						&stbuf->extension,
231 						&stbuf->n_uid, &stbuf->n_gid,
232 						&stbuf->n_muid);
233 				if (errcode)
234 					p9stat_free(stbuf);
235 			}
236 			break;
237 		case 'D':{
238 				int32_t *count = va_arg(ap, int32_t *);
239 				void **data = va_arg(ap, void **);
240 
241 				errcode =
242 				    p9pdu_readf(pdu, optional, "d", count);
243 				if (!errcode) {
244 					*count =
245 					    MIN(*count,
246 						pdu->size - pdu->offset);
247 					*data = &pdu->sdata[pdu->offset];
248 				}
249 			}
250 			break;
251 		case 'T':{
252 				int16_t *nwname = va_arg(ap, int16_t *);
253 				char ***wnames = va_arg(ap, char ***);
254 
255 				errcode =
256 				    p9pdu_readf(pdu, optional, "w", nwname);
257 				if (!errcode) {
258 					*wnames =
259 					    kmalloc(sizeof(char *) * *nwname,
260 						    GFP_KERNEL);
261 					if (!*wnames)
262 						errcode = -ENOMEM;
263 				}
264 
265 				if (!errcode) {
266 					int i;
267 
268 					for (i = 0; i < *nwname; i++) {
269 						errcode =
270 						    p9pdu_readf(pdu, optional,
271 								"s",
272 								&(*wnames)[i]);
273 						if (errcode)
274 							break;
275 					}
276 				}
277 
278 				if (errcode) {
279 					if (*wnames) {
280 						int i;
281 
282 						for (i = 0; i < *nwname; i++)
283 							kfree((*wnames)[i]);
284 					}
285 					kfree(*wnames);
286 					*wnames = NULL;
287 				}
288 			}
289 			break;
290 		case 'R':{
291 				int16_t *nwqid = va_arg(ap, int16_t *);
292 				struct p9_qid **wqids =
293 				    va_arg(ap, struct p9_qid **);
294 
295 				*wqids = NULL;
296 
297 				errcode =
298 				    p9pdu_readf(pdu, optional, "w", nwqid);
299 				if (!errcode) {
300 					*wqids =
301 					    kmalloc(*nwqid *
302 						    sizeof(struct p9_qid),
303 						    GFP_KERNEL);
304 					if (*wqids == NULL)
305 						errcode = -ENOMEM;
306 				}
307 
308 				if (!errcode) {
309 					int i;
310 
311 					for (i = 0; i < *nwqid; i++) {
312 						errcode =
313 						    p9pdu_readf(pdu, optional,
314 								"Q",
315 								&(*wqids)[i]);
316 						if (errcode)
317 							break;
318 					}
319 				}
320 
321 				if (errcode) {
322 					kfree(*wqids);
323 					*wqids = NULL;
324 				}
325 			}
326 			break;
327 		case '?':
328 			if (!optional)
329 				return 0;
330 			break;
331 		default:
332 			BUG();
333 			break;
334 		}
335 
336 		if (errcode)
337 			break;
338 	}
339 
340 	return errcode;
341 }
342 
343 int
344 p9pdu_vwritef(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
345 {
346 	const char *ptr;
347 	int errcode = 0;
348 
349 	for (ptr = fmt; *ptr; ptr++) {
350 		switch (*ptr) {
351 		case 'b':{
352 				int8_t val = va_arg(ap, int);
353 				if (pdu_write(pdu, &val, sizeof(val)))
354 					errcode = -EFAULT;
355 			}
356 			break;
357 		case 'w':{
358 				int16_t val = va_arg(ap, int);
359 				if (pdu_write(pdu, &val, sizeof(val)))
360 					errcode = -EFAULT;
361 			}
362 			break;
363 		case 'd':{
364 				int32_t val = va_arg(ap, int32_t);
365 				if (pdu_write(pdu, &val, sizeof(val)))
366 					errcode = -EFAULT;
367 			}
368 			break;
369 		case 'q':{
370 				int64_t val = va_arg(ap, int64_t);
371 				if (pdu_write(pdu, &val, sizeof(val)))
372 					errcode = -EFAULT;
373 			}
374 			break;
375 		case 's':{
376 				const char *ptr = va_arg(ap, const char *);
377 				int16_t len = 0;
378 				if (ptr)
379 					len = MIN(strlen(ptr), USHORT_MAX);
380 
381 				errcode = p9pdu_writef(pdu, optional, "w", len);
382 				if (!errcode && pdu_write(pdu, ptr, len))
383 					errcode = -EFAULT;
384 			}
385 			break;
386 		case 'Q':{
387 				const struct p9_qid *qid =
388 				    va_arg(ap, const struct p9_qid *);
389 				errcode =
390 				    p9pdu_writef(pdu, optional, "bdq",
391 						 qid->type, qid->version,
392 						 qid->path);
393 			} break;
394 		case 'S':{
395 				const struct p9_wstat *stbuf =
396 				    va_arg(ap, const struct p9_wstat *);
397 				errcode =
398 				    p9pdu_writef(pdu, optional,
399 						 "wwdQdddqssss?sddd",
400 						 stbuf->size, stbuf->type,
401 						 stbuf->dev, &stbuf->qid,
402 						 stbuf->mode, stbuf->atime,
403 						 stbuf->mtime, stbuf->length,
404 						 stbuf->name, stbuf->uid,
405 						 stbuf->gid, stbuf->muid,
406 						 stbuf->extension, stbuf->n_uid,
407 						 stbuf->n_gid, stbuf->n_muid);
408 			} break;
409 		case 'D':{
410 				int32_t count = va_arg(ap, int32_t);
411 				const void *data = va_arg(ap, const void *);
412 
413 				errcode =
414 				    p9pdu_writef(pdu, optional, "d", count);
415 				if (!errcode && pdu_write(pdu, data, count))
416 					errcode = -EFAULT;
417 			}
418 			break;
419 		case 'U':{
420 				int32_t count = va_arg(ap, int32_t);
421 				const char __user *udata =
422 						va_arg(ap, const void *);
423 				errcode =
424 				    p9pdu_writef(pdu, optional, "d", count);
425 				if (!errcode && pdu_write_u(pdu, udata, count))
426 					errcode = -EFAULT;
427 			}
428 			break;
429 		case 'T':{
430 				int16_t nwname = va_arg(ap, int);
431 				const char **wnames = va_arg(ap, const char **);
432 
433 				errcode =
434 				    p9pdu_writef(pdu, optional, "w", nwname);
435 				if (!errcode) {
436 					int i;
437 
438 					for (i = 0; i < nwname; i++) {
439 						errcode =
440 						    p9pdu_writef(pdu, optional,
441 								 "s",
442 								 wnames[i]);
443 						if (errcode)
444 							break;
445 					}
446 				}
447 			}
448 			break;
449 		case 'R':{
450 				int16_t nwqid = va_arg(ap, int);
451 				struct p9_qid *wqids =
452 				    va_arg(ap, struct p9_qid *);
453 
454 				errcode =
455 				    p9pdu_writef(pdu, optional, "w", nwqid);
456 				if (!errcode) {
457 					int i;
458 
459 					for (i = 0; i < nwqid; i++) {
460 						errcode =
461 						    p9pdu_writef(pdu, optional,
462 								 "Q",
463 								 &wqids[i]);
464 						if (errcode)
465 							break;
466 					}
467 				}
468 			}
469 			break;
470 		case '?':
471 			if (!optional)
472 				return 0;
473 			break;
474 		default:
475 			BUG();
476 			break;
477 		}
478 
479 		if (errcode)
480 			break;
481 	}
482 
483 	return errcode;
484 }
485 
486 int p9pdu_readf(struct p9_fcall *pdu, int optional, const char *fmt, ...)
487 {
488 	va_list ap;
489 	int ret;
490 
491 	va_start(ap, fmt);
492 	ret = p9pdu_vreadf(pdu, optional, fmt, ap);
493 	va_end(ap);
494 
495 	return ret;
496 }
497 
498 static int
499 p9pdu_writef(struct p9_fcall *pdu, int optional, const char *fmt, ...)
500 {
501 	va_list ap;
502 	int ret;
503 
504 	va_start(ap, fmt);
505 	ret = p9pdu_vwritef(pdu, optional, fmt, ap);
506 	va_end(ap);
507 
508 	return ret;
509 }
510 
511 int p9stat_read(char *buf, int len, struct p9_wstat *st, int dotu)
512 {
513 	struct p9_fcall fake_pdu;
514 	int ret;
515 
516 	fake_pdu.size = len;
517 	fake_pdu.capacity = len;
518 	fake_pdu.sdata = buf;
519 	fake_pdu.offset = 0;
520 
521 	ret = p9pdu_readf(&fake_pdu, dotu, "S", st);
522 	if (ret) {
523 		P9_DPRINTK(P9_DEBUG_9P, "<<< p9stat_read failed: %d\n", ret);
524 		p9pdu_dump(1, &fake_pdu);
525 	}
526 
527 	return ret;
528 }
529 EXPORT_SYMBOL(p9stat_read);
530 
531 int p9pdu_prepare(struct p9_fcall *pdu, int16_t tag, int8_t type)
532 {
533 	return p9pdu_writef(pdu, 0, "dbw", 0, type, tag);
534 }
535 
536 int p9pdu_finalize(struct p9_fcall *pdu)
537 {
538 	int size = pdu->size;
539 	int err;
540 
541 	pdu->size = 0;
542 	err = p9pdu_writef(pdu, 0, "d", size);
543 	pdu->size = size;
544 
545 	if ((p9_debug_level & P9_DEBUG_PKT) == P9_DEBUG_PKT)
546 		p9pdu_dump(0, pdu);
547 
548 	P9_DPRINTK(P9_DEBUG_9P, ">>> size=%d type: %d tag: %d\n", pdu->size,
549 							pdu->id, pdu->tag);
550 
551 	return err;
552 }
553 
554 void p9pdu_reset(struct p9_fcall *pdu)
555 {
556 	pdu->offset = 0;
557 	pdu->size = 0;
558 }
559