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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * 9P Protocol Support Code
4 *
5 * Copyright (C) 2008 by Eric Van Hensbergen <[email protected]>
6 *
7 * Base on code from Anthony Liguori <[email protected]>
8 * Copyright (C) 2008 by IBM, Corp.
9 */
10
11#include <linux/module.h>
12#include <linux/errno.h>
13#include <linux/kernel.h>
14#include <linux/uaccess.h>
15#include <linux/slab.h>
16#include <linux/sched.h>
17#include <linux/stddef.h>
18#include <linux/types.h>
19#include <linux/uio.h>
20#include <net/9p/9p.h>
21#include <net/9p/client.h>
22#include "protocol.h"
23
24#include <trace/events/9p.h>
25
26/* len[2] text[len] */
27#define P9_STRLEN(s) \
28 (2 + min_t(size_t, s ? strlen(s) : 0, USHRT_MAX))
29
30/**
31 * p9_msg_buf_size - Returns a buffer size sufficiently large to hold the
32 * intended 9p message.
33 * @c: client
34 * @type: message type
35 * @fmt: format template for assembling request message
36 * (see p9pdu_vwritef)
37 * @ap: variable arguments to be fed to passed format template
38 * (see p9pdu_vwritef)
39 *
40 * Note: Even for response types (P9_R*) the format template and variable
41 * arguments must always be for the originating request type (P9_T*).
42 */
43size_t p9_msg_buf_size(struct p9_client *c, enum p9_msg_t type,
44 const char *fmt, va_list ap)
45{
46 /* size[4] type[1] tag[2] */
47 const int hdr = 4 + 1 + 2;
48 /* ename[s] errno[4] */
49 const int rerror_size = hdr + P9_ERRMAX + 4;
50 /* ecode[4] */
51 const int rlerror_size = hdr + 4;
52 const int err_size =
53 c->proto_version == p9_proto_2000L ? rlerror_size : rerror_size;
54
55 static_assert(NAME_MAX <= 4*1024, "p9_msg_buf_size() currently assumes "
56 "a max. allowed directory entry name length of 4k");
57
58 switch (type) {
59
60 /* message types not used at all */
61 case P9_TERROR:
62 case P9_TLERROR:
63 case P9_TAUTH:
64 case P9_RAUTH:
65 BUG();
66
67 /* variable length & potentially large message types */
68 case P9_TATTACH:
69 BUG_ON(strcmp("ddss?u", fmt));
70 va_arg(ap, int32_t);
71 va_arg(ap, int32_t);
72 {
73 const char *uname = va_arg(ap, const char *);
74 const char *aname = va_arg(ap, const char *);
75 /* fid[4] afid[4] uname[s] aname[s] n_uname[4] */
76 return hdr + 4 + 4 + P9_STRLEN(uname) + P9_STRLEN(aname) + 4;
77 }
78 case P9_TWALK:
79 BUG_ON(strcmp("ddT", fmt));
80 va_arg(ap, int32_t);
81 va_arg(ap, int32_t);
82 {
83 uint i, nwname = va_arg(ap, int);
84 size_t wname_all;
85 const char **wnames = va_arg(ap, const char **);
86 for (i = 0, wname_all = 0; i < nwname; ++i) {
87 wname_all += P9_STRLEN(wnames[i]);
88 }
89 /* fid[4] newfid[4] nwname[2] nwname*(wname[s]) */
90 return hdr + 4 + 4 + 2 + wname_all;
91 }
92 case P9_RWALK:
93 BUG_ON(strcmp("ddT", fmt));
94 va_arg(ap, int32_t);
95 va_arg(ap, int32_t);
96 {
97 uint nwname = va_arg(ap, int);
98 /* nwqid[2] nwqid*(wqid[13]) */
99 return max_t(size_t, hdr + 2 + nwname * 13, err_size);
100 }
101 case P9_TCREATE:
102 BUG_ON(strcmp("dsdb?s", fmt));
103 va_arg(ap, int32_t);
104 {
105 const char *name = va_arg(ap, const char *);
106 if (c->proto_version == p9_proto_legacy) {
107 /* fid[4] name[s] perm[4] mode[1] */
108 return hdr + 4 + P9_STRLEN(name) + 4 + 1;
109 } else {
110 va_arg(ap, int32_t);
111 va_arg(ap, int);
112 {
113 const char *ext = va_arg(ap, const char *);
114 /* fid[4] name[s] perm[4] mode[1] extension[s] */
115 return hdr + 4 + P9_STRLEN(name) + 4 + 1 + P9_STRLEN(ext);
116 }
117 }
118 }
119 case P9_TLCREATE:
120 BUG_ON(strcmp("dsddg", fmt));
121 va_arg(ap, int32_t);
122 {
123 const char *name = va_arg(ap, const char *);
124 /* fid[4] name[s] flags[4] mode[4] gid[4] */
125 return hdr + 4 + P9_STRLEN(name) + 4 + 4 + 4;
126 }
127 case P9_RREAD:
128 case P9_RREADDIR:
129 BUG_ON(strcmp("dqd", fmt));
130 va_arg(ap, int32_t);
131 va_arg(ap, int64_t);
132 {
133 const int32_t count = va_arg(ap, int32_t);
134 /* count[4] data[count] */
135 return max_t(size_t, hdr + 4 + count, err_size);
136 }
137 case P9_TWRITE:
138 BUG_ON(strcmp("dqV", fmt));
139 va_arg(ap, int32_t);
140 va_arg(ap, int64_t);
141 {
142 const int32_t count = va_arg(ap, int32_t);
143 /* fid[4] offset[8] count[4] data[count] */
144 return hdr + 4 + 8 + 4 + count;
145 }
146 case P9_TRENAMEAT:
147 BUG_ON(strcmp("dsds", fmt));
148 va_arg(ap, int32_t);
149 {
150 const char *oldname, *newname;
151 oldname = va_arg(ap, const char *);
152 va_arg(ap, int32_t);
153 newname = va_arg(ap, const char *);
154 /* olddirfid[4] oldname[s] newdirfid[4] newname[s] */
155 return hdr + 4 + P9_STRLEN(oldname) + 4 + P9_STRLEN(newname);
156 }
157 case P9_TSYMLINK:
158 BUG_ON(strcmp("dssg", fmt));
159 va_arg(ap, int32_t);
160 {
161 const char *name = va_arg(ap, const char *);
162 const char *symtgt = va_arg(ap, const char *);
163 /* fid[4] name[s] symtgt[s] gid[4] */
164 return hdr + 4 + P9_STRLEN(name) + P9_STRLEN(symtgt) + 4;
165 }
166
167 case P9_RERROR:
168 return rerror_size;
169 case P9_RLERROR:
170 return rlerror_size;
171
172 /* small message types */
173 case P9_TWSTAT:
174 case P9_RSTAT:
175 case P9_RREADLINK:
176 case P9_TXATTRWALK:
177 case P9_TXATTRCREATE:
178 case P9_TLINK:
179 case P9_TMKDIR:
180 case P9_TMKNOD:
181 case P9_TRENAME:
182 case P9_TUNLINKAT:
183 case P9_TLOCK:
184 return 8 * 1024;
185
186 /* tiny message types */
187 default:
188 return 4 * 1024;
189
190 }
191}
192
193static int
194p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...);
195
196void p9stat_free(struct p9_wstat *stbuf)
197{
198 kfree(stbuf->name);
199 stbuf->name = NULL;
200 kfree(stbuf->uid);
201 stbuf->uid = NULL;
202 kfree(stbuf->gid);
203 stbuf->gid = NULL;
204 kfree(stbuf->muid);
205 stbuf->muid = NULL;
206 kfree(stbuf->extension);
207 stbuf->extension = NULL;
208}
209EXPORT_SYMBOL(p9stat_free);
210
211size_t pdu_read(struct p9_fcall *pdu, void *data, size_t size)
212{
213 size_t len = min(pdu->size - pdu->offset, size);
214
215 memcpy(data, &pdu->sdata[pdu->offset], len);
216 pdu->offset += len;
217 return size - len;
218}
219
220static size_t pdu_write(struct p9_fcall *pdu, const void *data, size_t size)
221{
222 size_t len = min(pdu->capacity - pdu->size, size);
223
224 memcpy(&pdu->sdata[pdu->size], data, len);
225 pdu->size += len;
226 return size - len;
227}
228
229static size_t
230pdu_write_u(struct p9_fcall *pdu, struct iov_iter *from, size_t size)
231{
232 size_t len = min(pdu->capacity - pdu->size, size);
233
234 if (!copy_from_iter_full(&pdu->sdata[pdu->size], len, from))
235 len = 0;
236
237 pdu->size += len;
238 return size - len;
239}
240
241/* b - int8_t
242 * w - int16_t
243 * d - int32_t
244 * q - int64_t
245 * s - string
246 * u - numeric uid
247 * g - numeric gid
248 * S - stat
249 * Q - qid
250 * D - data blob (int32_t size followed by void *, results are not freed)
251 * T - array of strings (int16_t count, followed by strings)
252 * R - array of qids (int16_t count, followed by qids)
253 * A - stat for 9p2000.L (p9_stat_dotl)
254 * ? - if optional = 1, continue parsing
255 */
256
257static int
258p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt,
259 va_list ap)
260{
261 const char *ptr;
262 int errcode = 0;
263
264 for (ptr = fmt; *ptr; ptr++) {
265 switch (*ptr) {
266 case 'b':{
267 int8_t *val = va_arg(ap, int8_t *);
268 if (pdu_read(pdu, val, sizeof(*val))) {
269 errcode = -EFAULT;
270 break;
271 }
272 }
273 break;
274 case 'w':{
275 int16_t *val = va_arg(ap, int16_t *);
276 __le16 le_val;
277 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
278 errcode = -EFAULT;
279 break;
280 }
281 *val = le16_to_cpu(le_val);
282 }
283 break;
284 case 'd':{
285 int32_t *val = va_arg(ap, int32_t *);
286 __le32 le_val;
287 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
288 errcode = -EFAULT;
289 break;
290 }
291 *val = le32_to_cpu(le_val);
292 }
293 break;
294 case 'q':{
295 int64_t *val = va_arg(ap, int64_t *);
296 __le64 le_val;
297 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
298 errcode = -EFAULT;
299 break;
300 }
301 *val = le64_to_cpu(le_val);
302 }
303 break;
304 case 's':{
305 char **sptr = va_arg(ap, char **);
306 uint16_t len;
307
308 errcode = p9pdu_readf(pdu, proto_version,
309 "w", &len);
310 if (errcode)
311 break;
312
313 *sptr = kmalloc(len + 1, GFP_NOFS);
314 if (*sptr == NULL) {
315 errcode = -ENOMEM;
316 break;
317 }
318 if (pdu_read(pdu, *sptr, len)) {
319 errcode = -EFAULT;
320 kfree(*sptr);
321 *sptr = NULL;
322 } else
323 (*sptr)[len] = 0;
324 }
325 break;
326 case 'u': {
327 kuid_t *uid = va_arg(ap, kuid_t *);
328 __le32 le_val;
329 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
330 errcode = -EFAULT;
331 break;
332 }
333 *uid = make_kuid(&init_user_ns,
334 le32_to_cpu(le_val));
335 } break;
336 case 'g': {
337 kgid_t *gid = va_arg(ap, kgid_t *);
338 __le32 le_val;
339 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
340 errcode = -EFAULT;
341 break;
342 }
343 *gid = make_kgid(&init_user_ns,
344 le32_to_cpu(le_val));
345 } break;
346 case 'Q':{
347 struct p9_qid *qid =
348 va_arg(ap, struct p9_qid *);
349
350 errcode = p9pdu_readf(pdu, proto_version, "bdq",
351 &qid->type, &qid->version,
352 &qid->path);
353 }
354 break;
355 case 'S':{
356 struct p9_wstat *stbuf =
357 va_arg(ap, struct p9_wstat *);
358
359 memset(stbuf, 0, sizeof(struct p9_wstat));
360 stbuf->n_uid = stbuf->n_muid = INVALID_UID;
361 stbuf->n_gid = INVALID_GID;
362
363 errcode =
364 p9pdu_readf(pdu, proto_version,
365 "wwdQdddqssss?sugu",
366 &stbuf->size, &stbuf->type,
367 &stbuf->dev, &stbuf->qid,
368 &stbuf->mode, &stbuf->atime,
369 &stbuf->mtime, &stbuf->length,
370 &stbuf->name, &stbuf->uid,
371 &stbuf->gid, &stbuf->muid,
372 &stbuf->extension,
373 &stbuf->n_uid, &stbuf->n_gid,
374 &stbuf->n_muid);
375 if (errcode)
376 p9stat_free(stbuf);
377 }
378 break;
379 case 'D':{
380 uint32_t *count = va_arg(ap, uint32_t *);
381 void **data = va_arg(ap, void **);
382
383 errcode =
384 p9pdu_readf(pdu, proto_version, "d", count);
385 if (!errcode) {
386 *count =
387 min_t(uint32_t, *count,
388 pdu->size - pdu->offset);
389 *data = &pdu->sdata[pdu->offset];
390 }
391 }
392 break;
393 case 'T':{
394 uint16_t *nwname = va_arg(ap, uint16_t *);
395 char ***wnames = va_arg(ap, char ***);
396
397 *wnames = NULL;
398
399 errcode = p9pdu_readf(pdu, proto_version,
400 "w", nwname);
401 if (!errcode) {
402 *wnames =
403 kmalloc_array(*nwname,
404 sizeof(char *),
405 GFP_NOFS);
406 if (!*wnames)
407 errcode = -ENOMEM;
408 else
409 (*wnames)[0] = NULL;
410 }
411
412 if (!errcode) {
413 int i;
414
415 for (i = 0; i < *nwname; i++) {
416 errcode =
417 p9pdu_readf(pdu,
418 proto_version,
419 "s",
420 &(*wnames)[i]);
421 if (errcode) {
422 (*wnames)[i] = NULL;
423 break;
424 }
425 }
426 }
427
428 if (errcode) {
429 if (*wnames) {
430 int i;
431
432 for (i = 0; i < *nwname; i++) {
433 if (!(*wnames)[i])
434 break;
435 kfree((*wnames)[i]);
436 }
437 kfree(*wnames);
438 *wnames = NULL;
439 }
440 }
441 }
442 break;
443 case 'R':{
444 uint16_t *nwqid = va_arg(ap, uint16_t *);
445 struct p9_qid **wqids =
446 va_arg(ap, struct p9_qid **);
447
448 *wqids = NULL;
449
450 errcode =
451 p9pdu_readf(pdu, proto_version, "w", nwqid);
452 if (!errcode) {
453 *wqids =
454 kmalloc_objs(struct p9_qid, *nwqid,
455 GFP_NOFS);
456 if (*wqids == NULL)
457 errcode = -ENOMEM;
458 }
459
460 if (!errcode) {
461 int i;
462
463 for (i = 0; i < *nwqid; i++) {
464 errcode =
465 p9pdu_readf(pdu,
466 proto_version,
467 "Q",
468 &(*wqids)[i]);
469 if (errcode)
470 break;
471 }
472 }
473
474 if (errcode) {
475 kfree(*wqids);
476 *wqids = NULL;
477 }
478 }
479 break;
480 case 'A': {
481 struct p9_stat_dotl *stbuf =
482 va_arg(ap, struct p9_stat_dotl *);
483
484 memset(stbuf, 0, sizeof(struct p9_stat_dotl));
485 errcode =
486 p9pdu_readf(pdu, proto_version,
487 "qQdugqqqqqqqqqqqqqqq",
488 &stbuf->st_result_mask,
489 &stbuf->qid,
490 &stbuf->st_mode,
491 &stbuf->st_uid, &stbuf->st_gid,
492 &stbuf->st_nlink,
493 &stbuf->st_rdev, &stbuf->st_size,
494 &stbuf->st_blksize, &stbuf->st_blocks,
495 &stbuf->st_atime_sec,
496 &stbuf->st_atime_nsec,
497 &stbuf->st_mtime_sec,
498 &stbuf->st_mtime_nsec,
499 &stbuf->st_ctime_sec,
500 &stbuf->st_ctime_nsec,
501 &stbuf->st_btime_sec,
502 &stbuf->st_btime_nsec,
503 &stbuf->st_gen,
504 &stbuf->st_data_version);
505 }
506 break;
507 case '?':
508 if ((proto_version != p9_proto_2000u) &&
509 (proto_version != p9_proto_2000L))
510 return 0;
511 break;
512 default:
513 BUG();
514 break;
515 }
516
517 if (errcode)
518 break;
519 }
520
521 return errcode;
522}
523
524int
525p9pdu_vwritef(struct p9_fcall *pdu, int proto_version, const char *fmt,
526 va_list ap)
527{
528 const char *ptr;
529 int errcode = 0;
530
531 for (ptr = fmt; *ptr; ptr++) {
532 switch (*ptr) {
533 case 'b':{
534 int8_t val = va_arg(ap, int);
535 if (pdu_write(pdu, &val, sizeof(val)))
536 errcode = -EFAULT;
537 }
538 break;
539 case 'w':{
540 __le16 val = cpu_to_le16(va_arg(ap, int));
541 if (pdu_write(pdu, &val, sizeof(val)))
542 errcode = -EFAULT;
543 }
544 break;
545 case 'd':{
546 __le32 val = cpu_to_le32(va_arg(ap, int32_t));
547 if (pdu_write(pdu, &val, sizeof(val)))
548 errcode = -EFAULT;
549 }
550 break;
551 case 'q':{
552 __le64 val = cpu_to_le64(va_arg(ap, int64_t));
553 if (pdu_write(pdu, &val, sizeof(val)))
554 errcode = -EFAULT;
555 }
556 break;
557 case 's':{
558 const char *sptr = va_arg(ap, const char *);
559 uint16_t len = 0;
560 if (sptr)
561 len = min_t(size_t, strlen(sptr),
562 USHRT_MAX);
563
564 errcode = p9pdu_writef(pdu, proto_version,
565 "w", len);
566 if (!errcode && pdu_write(pdu, sptr, len))
567 errcode = -EFAULT;
568 }
569 break;
570 case 'u': {
571 kuid_t uid = va_arg(ap, kuid_t);
572 __le32 val = cpu_to_le32(
573 from_kuid(&init_user_ns, uid));
574 if (pdu_write(pdu, &val, sizeof(val)))
575 errcode = -EFAULT;
576 } break;
577 case 'g': {
578 kgid_t gid = va_arg(ap, kgid_t);
579 __le32 val = cpu_to_le32(
580 from_kgid(&init_user_ns, gid));
581 if (pdu_write(pdu, &val, sizeof(val)))
582 errcode = -EFAULT;
583 } break;
584 case 'Q':{
585 const struct p9_qid *qid =
586 va_arg(ap, const struct p9_qid *);
587 errcode =
588 p9pdu_writef(pdu, proto_version, "bdq",
589 qid->type, qid->version,
590 qid->path);
591 } break;
592 case 'S':{
593 const struct p9_wstat *stbuf =
594 va_arg(ap, const struct p9_wstat *);
595 errcode =
596 p9pdu_writef(pdu, proto_version,
597 "wwdQdddqssss?sugu",
598 stbuf->size, stbuf->type,
599 stbuf->dev, &stbuf->qid,
600 stbuf->mode, stbuf->atime,
601 stbuf->mtime, stbuf->length,
602 stbuf->name, stbuf->uid,
603 stbuf->gid, stbuf->muid,
604 stbuf->extension, stbuf->n_uid,
605 stbuf->n_gid, stbuf->n_muid);
606 } break;
607 case 'V':{
608 uint32_t count = va_arg(ap, uint32_t);
609 struct iov_iter *from =
610 va_arg(ap, struct iov_iter *);
611 errcode = p9pdu_writef(pdu, proto_version, "d",
612 count);
613 if (!errcode && pdu_write_u(pdu, from, count))
614 errcode = -EFAULT;
615 }
616 break;
617 case 'T':{
618 uint16_t nwname = va_arg(ap, int);
619 const char **wnames = va_arg(ap, const char **);
620
621 errcode = p9pdu_writef(pdu, proto_version, "w",
622 nwname);
623 if (!errcode) {
624 int i;
625
626 for (i = 0; i < nwname; i++) {
627 errcode =
628 p9pdu_writef(pdu,
629 proto_version,
630 "s",
631 wnames[i]);
632 if (errcode)
633 break;
634 }
635 }
636 }
637 break;
638 case 'R':{
639 uint16_t nwqid = va_arg(ap, int);
640 struct p9_qid *wqids =
641 va_arg(ap, struct p9_qid *);
642
643 errcode = p9pdu_writef(pdu, proto_version, "w",
644 nwqid);
645 if (!errcode) {
646 int i;
647
648 for (i = 0; i < nwqid; i++) {
649 errcode =
650 p9pdu_writef(pdu,
651 proto_version,
652 "Q",
653 &wqids[i]);
654 if (errcode)
655 break;
656 }
657 }
658 }
659 break;
660 case 'I':{
661 struct p9_iattr_dotl *p9attr = va_arg(ap,
662 struct p9_iattr_dotl *);
663
664 errcode = p9pdu_writef(pdu, proto_version,
665 "ddugqqqqq",
666 p9attr->valid,
667 p9attr->mode,
668 p9attr->uid,
669 p9attr->gid,
670 p9attr->size,
671 p9attr->atime_sec,
672 p9attr->atime_nsec,
673 p9attr->mtime_sec,
674 p9attr->mtime_nsec);
675 }
676 break;
677 case '?':
678 if ((proto_version != p9_proto_2000u) &&
679 (proto_version != p9_proto_2000L))
680 return 0;
681 break;
682 default:
683 BUG();
684 break;
685 }
686
687 if (errcode)
688 break;
689 }
690
691 return errcode;
692}
693
694int p9pdu_readf(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
695{
696 va_list ap;
697 int ret;
698
699 va_start(ap, fmt);
700 ret = p9pdu_vreadf(pdu, proto_version, fmt, ap);
701 va_end(ap);
702
703 return ret;
704}
705
706static int
707p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
708{
709 va_list ap;
710 int ret;
711
712 va_start(ap, fmt);
713 ret = p9pdu_vwritef(pdu, proto_version, fmt, ap);
714 va_end(ap);
715
716 return ret;
717}
718
719int p9stat_read(struct p9_client *clnt, char *buf, int len, struct p9_wstat *st)
720{
721 struct p9_fcall fake_pdu;
722 int ret;
723
724 fake_pdu.size = len;
725 fake_pdu.capacity = len;
726 fake_pdu.sdata = buf;
727 fake_pdu.offset = 0;
728
729 ret = p9pdu_readf(&fake_pdu, clnt->proto_version, "S", st);
730 if (ret) {
731 p9_debug(P9_DEBUG_9P, "<<< p9stat_read failed: %d\n", ret);
732 trace_9p_protocol_dump(clnt, &fake_pdu);
733 return ret;
734 }
735
736 return fake_pdu.offset;
737}
738EXPORT_SYMBOL(p9stat_read);
739
740int p9pdu_prepare(struct p9_fcall *pdu, int16_t tag, int8_t type)
741{
742 pdu->id = type;
743 return p9pdu_writef(pdu, 0, "dbw", 0, type, tag);
744}
745
746int p9pdu_finalize(struct p9_client *clnt, struct p9_fcall *pdu)
747{
748 int size = pdu->size;
749 int err;
750
751 pdu->size = 0;
752 err = p9pdu_writef(pdu, 0, "d", size);
753 pdu->size = size;
754
755 trace_9p_protocol_dump(clnt, pdu);
756 p9_debug(P9_DEBUG_9P, ">>> size=%d type: %d tag: %d\n",
757 pdu->size, pdu->id, pdu->tag);
758
759 return err;
760}
761
762void p9pdu_reset(struct p9_fcall *pdu)
763{
764 pdu->offset = 0;
765 pdu->size = 0;
766}
767
768int p9dirent_read(struct p9_client *clnt, char *buf, int len,
769 struct p9_dirent *dirent)
770{
771 struct p9_fcall fake_pdu;
772 int ret;
773 char *nameptr;
774
775 fake_pdu.size = len;
776 fake_pdu.capacity = len;
777 fake_pdu.sdata = buf;
778 fake_pdu.offset = 0;
779
780 ret = p9pdu_readf(&fake_pdu, clnt->proto_version, "Qqbs", &dirent->qid,
781 &dirent->d_off, &dirent->d_type, &nameptr);
782 if (ret) {
783 p9_debug(P9_DEBUG_9P, "<<< p9dirent_read failed: %d\n", ret);
784 trace_9p_protocol_dump(clnt, &fake_pdu);
785 return ret;
786 }
787
788 ret = strscpy(dirent->d_name, nameptr, sizeof(dirent->d_name));
789 if (ret < 0) {
790 p9_debug(P9_DEBUG_ERROR,
791 "On the wire dirent name too long: %s\n",
792 nameptr);
793 kfree(nameptr);
794 return ret;
795 }
796 kfree(nameptr);
797
798 return fake_pdu.offset;
799}
800EXPORT_SYMBOL(p9dirent_read);