Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
[firefly-linux-kernel-4.4.55.git] / net / 9p / protocol.c
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);