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
43static int
44p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...);
45
46void 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}
54EXPORT_SYMBOL(p9stat_free);
55
56size_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
64static 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
72static size_t
73pdu_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
101static int
102p9pdu_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
359int
360p9pdu_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
529int 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
541static int
542p9pdu_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
554int 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}
572EXPORT_SYMBOL(p9stat_read);
573
574int 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
580int 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
596void p9pdu_reset(struct p9_fcall *pdu)
597{
598	pdu->offset = 0;
599	pdu->size = 0;
600}
601
602int 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
625out:
626	return fake_pdu.offset;
627}
628EXPORT_SYMBOL(p9dirent_read);
629