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 <net/9p/9p.h>
  37 #include <net/9p/client.h>
  38 #include "protocol.h"
  39
  40 #include <trace/events/9p.h>
  41
  42 static int
  43 p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...);
  44
  45 void p9stat_free(struct p9_wstat *stbuf)
  46 {
  47         kfree(stbuf->name);
  48         kfree(stbuf->uid);
  49         kfree(stbuf->gid);
  50         kfree(stbuf->muid);
  51         kfree(stbuf->extension);
  52 }
  53 EXPORT_SYMBOL(p9stat_free);
  54
  55 size_t pdu_read(struct p9_fcall *pdu, void *data, size_t size)
  56 {
  57         size_t len = min(pdu->size - pdu->offset, size);
  58         memcpy(data, &pdu->sdata[pdu->offset], len);
  59         pdu->offset += len;
  60         return size - len;
  61 }
  62
  63 static size_t pdu_write(struct p9_fcall *pdu, const void *data, size_t size)
  64 {
  65         size_t len = min(pdu->capacity - pdu->size, size);
  66         memcpy(&pdu->sdata[pdu->size], data, len);
  67         pdu->size += len;
  68         return size - len;
  69 }
  70
  71 static size_t
  72 pdu_write_u(struct p9_fcall *pdu, const char __user *udata, size_t size)
  73 {
  74         size_t len = min(pdu->capacity - pdu->size, size);
  75         if (copy_from_user(&pdu->sdata[pdu->size], udata, len))
  76                 len = 0;
  77
  78         pdu->size += len;
  79         return size - len;
  80 }
  81
  82 /*
  83         b - int8_t
  84         w - int16_t
  85         d - int32_t
  86         q - int64_t
  87         s - string
  88         S - stat
  89         Q - qid
  90         D - data blob (int32_t size followed by void *, results are not freed)
  91         T - array of strings (int16_t count, followed by strings)
  92         R - array of qids (int16_t count, followed by qids)
  93         A - stat for 9p2000.L (p9_stat_dotl)
  94         ? - if optional = 1, continue parsing
  95 */
  96
  97 static int
  98 p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt,
  99         va_list ap)
 100 {
 101         const char *ptr;
 102         int errcode = 0;
 103
 104         for (ptr = fmt; *ptr; ptr++) {
 105                 switch (*ptr) {
 106                 case 'b':{
 107                                 int8_t *val = va_arg(ap, int8_t *);
 108                                 if (pdu_read(pdu, val, sizeof(*val))) {
 109                                         errcode = -EFAULT;
 110                                         break;
 111                                 }
 112                         }
 113                         break;
 114                 case 'w':{
 115                                 int16_t *val = va_arg(ap, int16_t *);
 116                                 __le16 le_val;
 117                                 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
 118                                         errcode = -EFAULT;
 119                                         break;
 120                                 }
 121                                 *val = le16_to_cpu(le_val);
 122                         }
 123                         break;
 124                 case 'd':{
 125                                 int32_t *val = va_arg(ap, int32_t *);
 126                                 __le32 le_val;
 127                                 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
 128                                         errcode = -EFAULT;
 129                                         break;
 130                                 }
 131                                 *val = le32_to_cpu(le_val);
 132                         }
 133                         break;
 134                 case 'q':{
 135                                 int64_t *val = va_arg(ap, int64_t *);
 136                                 __le64 le_val;
 137                                 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
 138                                         errcode = -EFAULT;
 139                                         break;
 140                                 }
 141                                 *val = le64_to_cpu(le_val);
 142                         }
 143                         break;
 144                 case 's':{
 145                                 char **sptr = va_arg(ap, char **);
 146                                 uint16_t len;
 147
 148                                 errcode = p9pdu_readf(pdu, proto_version,
 149                                                                 "w", &len);
 150                                 if (errcode)
 151                                         break;
 152
 153                                 *sptr = kmalloc(len + 1, GFP_NOFS);
 154                                 if (*sptr == NULL) {
 155                                         errcode = -EFAULT;
 156                                         break;
 157                                 }
 158                                 if (pdu_read(pdu, *sptr, len)) {
 159                                         errcode = -EFAULT;
 160                                         kfree(*sptr);
 161                                         *sptr = NULL;
 162                                 } else
 163                                         (*sptr)[len] = 0;
 164                         }
 165                         break;
 166                 case 'Q':{
 167                                 struct p9_qid *qid =
 168                                     va_arg(ap, struct p9_qid *);
 169
 170                                 errcode = p9pdu_readf(pdu, proto_version, "bdq",
 171                                                       &qid->type, &qid->version,
 172                                                       &qid->path);
 173                         }
 174                         break;
 175                 case 'S':{
 176                                 struct p9_wstat *stbuf =
 177                                     va_arg(ap, struct p9_wstat *);
 178
 179                                 memset(stbuf, 0, sizeof(struct p9_wstat));
 180                                 stbuf->n_uid = stbuf->n_gid = stbuf->n_muid =
 181                                                                         -1;
 182                                 errcode =
 183                                     p9pdu_readf(pdu, proto_version,
 184                                                 "wwdQdddqssss?sddd",
 185                                                 &stbuf->size, &stbuf->type,
 186                                                 &stbuf->dev, &stbuf->qid,
 187                                                 &stbuf->mode, &stbuf->atime,
 188                                                 &stbuf->mtime, &stbuf->length,
 189                                                 &stbuf->name, &stbuf->uid,
 190                                                 &stbuf->gid, &stbuf->muid,
 191                                                 &stbuf->extension,
 192                                                 &stbuf->n_uid, &stbuf->n_gid,
 193                                                 &stbuf->n_muid);
 194                                 if (errcode)
 195                                         p9stat_free(stbuf);
 196                         }
 197                         break;
 198                 case 'D':{
 199                                 uint32_t *count = va_arg(ap, uint32_t *);
 200                                 void **data = va_arg(ap, void **);
 201
 202                                 errcode =
 203                                     p9pdu_readf(pdu, proto_version, "d", count);
 204                                 if (!errcode) {
 205                                         *count =
 206                                             min_t(uint32_t, *count,
 207                                                   pdu->size - pdu->offset);
 208                                         *data = &pdu->sdata[pdu->offset];
 209                                 }
 210                         }
 211                         break;
 212                 case 'T':{
 213                                 uint16_t *nwname = va_arg(ap, uint16_t *);
 214                                 char ***wnames = va_arg(ap, char ***);
 215
 216                                 errcode = p9pdu_readf(pdu, proto_version,
 217                                                                 "w", nwname);
 218                                 if (!errcode) {
 219                                         *wnames =
 220                                             kmalloc(sizeof(char *) * *nwname,
 221                                                     GFP_NOFS);
 222                                         if (!*wnames)
 223                                                 errcode = -ENOMEM;
 224                                 }
 225
 226                                 if (!errcode) {
 227                                         int i;
 228
 229                                         for (i = 0; i < *nwname; i++) {
 230                                                 errcode =
 231                                                     p9pdu_readf(pdu,
 232                                                                 proto_version,
 233                                                                 "s",
 234                                                                 &(*wnames)[i]);
 235                                                 if (errcode)
 236                                                         break;
 237                                         }
 238                                 }
 239
 240                                 if (errcode) {
 241                                         if (*wnames) {
 242                                                 int i;
 243
 244                                                 for (i = 0; i < *nwname; i++)
 245                                                         kfree((*wnames)[i]);
 246                                         }
 247                                         kfree(*wnames);
 248                                         *wnames = NULL;
 249                                 }
 250                         }
 251                         break;
 252                 case 'R':{
 253                                 int16_t *nwqid = va_arg(ap, int16_t *);
 254                                 struct p9_qid **wqids =
 255                                     va_arg(ap, struct p9_qid **);
 256
 257                                 *wqids = NULL;
 258
 259                                 errcode =
 260                                     p9pdu_readf(pdu, proto_version, "w", nwqid);
 261                                 if (!errcode) {
 262                                         *wqids =
 263                                             kmalloc(*nwqid *
 264                                                     sizeof(struct p9_qid),
 265                                                     GFP_NOFS);
 266                                         if (*wqids == NULL)
 267                                                 errcode = -ENOMEM;
 268                                 }
 269
 270                                 if (!errcode) {
 271                                         int i;
 272
 273                                         for (i = 0; i < *nwqid; i++) {
 274                                                 errcode =
 275                                                     p9pdu_readf(pdu,
 276                                                                 proto_version,
 277                                                                 "Q",
 278                                                                 &(*wqids)[i]);
 279                                                 if (errcode)
 280                                                         break;
 281                                         }
 282                                 }
 283
 284                                 if (errcode) {
 285                                         kfree(*wqids);
 286                                         *wqids = NULL;
 287                                 }
 288                         }
 289                         break;
 290                 case 'A': {
 291                                 struct p9_stat_dotl *stbuf =
 292                                     va_arg(ap, struct p9_stat_dotl *);
 293
 294                                 memset(stbuf, 0, sizeof(struct p9_stat_dotl));
 295                                 errcode =
 296                                     p9pdu_readf(pdu, proto_version,
 297                                         "qQdddqqqqqqqqqqqqqqq",
 298                                         &stbuf->st_result_mask,
 299                                         &stbuf->qid,
 300                                         &stbuf->st_mode,
 301                                         &stbuf->st_uid, &stbuf->st_gid,
 302                                         &stbuf->st_nlink,
 303                                         &stbuf->st_rdev, &stbuf->st_size,
 304                                         &stbuf->st_blksize, &stbuf->st_blocks,
 305                                         &stbuf->st_atime_sec,
 306                                         &stbuf->st_atime_nsec,
 307                                         &stbuf->st_mtime_sec,
 308                                         &stbuf->st_mtime_nsec,
 309                                         &stbuf->st_ctime_sec,
 310                                         &stbuf->st_ctime_nsec,
 311                                         &stbuf->st_btime_sec,
 312                                         &stbuf->st_btime_nsec,
 313                                         &stbuf->st_gen,
 314                                         &stbuf->st_data_version);
 315                         }
 316                         break;
 317                 case '?':
 318                         if ((proto_version != p9_proto_2000u) &&
 319                                 (proto_version != p9_proto_2000L))
 320                                 return 0;
 321                         break;
 322                 default:
 323                         BUG();
 324                         break;
 325                 }
 326
 327                 if (errcode)
 328                         break;
 329         }
 330
 331         return errcode;
 332 }
 333
 334 int
 335 p9pdu_vwritef(struct p9_fcall *pdu, int proto_version, const char *fmt,
 336         va_list ap)
 337 {
 338         const char *ptr;
 339         int errcode = 0;
 340
 341         for (ptr = fmt; *ptr; ptr++) {
 342                 switch (*ptr) {
 343                 case 'b':{
 344                                 int8_t val = va_arg(ap, int);
 345                                 if (pdu_write(pdu, &val, sizeof(val)))
 346                                         errcode = -EFAULT;
 347                         }
 348                         break;
 349                 case 'w':{
 350                                 __le16 val = cpu_to_le16(va_arg(ap, int));
 351                                 if (pdu_write(pdu, &val, sizeof(val)))
 352                                         errcode = -EFAULT;
 353                         }
 354                         break;
 355                 case 'd':{
 356                                 __le32 val = cpu_to_le32(va_arg(ap, int32_t));
 357                                 if (pdu_write(pdu, &val, sizeof(val)))
 358                                         errcode = -EFAULT;
 359                         }
 360                         break;
 361                 case 'q':{
 362                                 __le64 val = cpu_to_le64(va_arg(ap, int64_t));
 363                                 if (pdu_write(pdu, &val, sizeof(val)))
 364                                         errcode = -EFAULT;
 365                         }
 366                         break;
 367                 case 's':{
 368                                 const char *sptr = va_arg(ap, const char *);
 369                                 uint16_t len = 0;
 370                                 if (sptr)
 371                                         len = min_t(uint16_t, strlen(sptr),
 372                                                                 USHRT_MAX);
 373
 374                                 errcode = p9pdu_writef(pdu, proto_version,
 375                                                                 "w", len);
 376                                 if (!errcode && pdu_write(pdu, sptr, len))
 377                                         errcode = -EFAULT;
 378                         }
 379                         break;
 380                 case 'Q':{
 381                                 const struct p9_qid *qid =
 382                                     va_arg(ap, const struct p9_qid *);
 383                                 errcode =
 384                                     p9pdu_writef(pdu, proto_version, "bdq",
 385                                                  qid->type, qid->version,
 386                                                  qid->path);
 387                         } break;
 388                 case 'S':{
 389                                 const struct p9_wstat *stbuf =
 390                                     va_arg(ap, const struct p9_wstat *);
 391                                 errcode =
 392                                     p9pdu_writef(pdu, proto_version,
 393                                                  "wwdQdddqssss?sddd",
 394                                                  stbuf->size, stbuf->type,
 395                                                  stbuf->dev, &stbuf->qid,
 396                                                  stbuf->mode, stbuf->atime,
 397                                                  stbuf->mtime, stbuf->length,
 398                                                  stbuf->name, stbuf->uid,
 399                                                  stbuf->gid, stbuf->muid,
 400                                                  stbuf->extension, stbuf->n_uid,
 401                                                  stbuf->n_gid, stbuf->n_muid);
 402                         } break;
 403                 case 'D':{
 404                                 uint32_t count = va_arg(ap, uint32_t);
 405                                 const void *data = va_arg(ap, const void *);
 406
 407                                 errcode = p9pdu_writef(pdu, proto_version, "d",
 408                                                                         count);
 409                                 if (!errcode && pdu_write(pdu, data, count))
 410                                         errcode = -EFAULT;
 411                         }
 412                         break;
 413                 case 'U':{
 414                                 int32_t count = va_arg(ap, int32_t);
 415                                 const char __user *udata =
 416                                                 va_arg(ap, const void __user *);
 417                                 errcode = p9pdu_writef(pdu, proto_version, "d",
 418                                                                         count);
 419                                 if (!errcode && pdu_write_u(pdu, udata, count))
 420                                         errcode = -EFAULT;
 421                         }
 422                         break;
 423                 case 'T':{
 424                                 uint16_t nwname = va_arg(ap, int);
 425                                 const char **wnames = va_arg(ap, const char **);
 426
 427                                 errcode = p9pdu_writef(pdu, proto_version, "w",
 428                                                                         nwname);
 429                                 if (!errcode) {
 430                                         int i;
 431
 432                                         for (i = 0; i < nwname; i++) {
 433                                                 errcode =
 434                                                     p9pdu_writef(pdu,
 435                                                                 proto_version,
 436                                                                  "s",
 437                                                                  wnames[i]);
 438                                                 if (errcode)
 439                                                         break;
 440                                         }
 441                                 }
 442                         }
 443                         break;
 444                 case 'R':{
 445                                 int16_t nwqid = va_arg(ap, int);
 446                                 struct p9_qid *wqids =
 447                                     va_arg(ap, struct p9_qid *);
 448
 449                                 errcode = p9pdu_writef(pdu, proto_version, "w",
 450                                                                         nwqid);
 451                                 if (!errcode) {
 452                                         int i;
 453
 454                                         for (i = 0; i < nwqid; i++) {
 455                                                 errcode =
 456                                                     p9pdu_writef(pdu,
 457                                                                 proto_version,
 458                                                                  "Q",
 459                                                                  &wqids[i]);
 460                                                 if (errcode)
 461                                                         break;
 462                                         }
 463                                 }
 464                         }
 465                         break;
 466                 case 'I':{
 467                                 struct p9_iattr_dotl *p9attr = va_arg(ap,
 468                                                         struct p9_iattr_dotl *);
 469
 470                                 errcode = p9pdu_writef(pdu, proto_version,
 471                                                         "ddddqqqqq",
 472                                                         p9attr->valid,
 473                                                         p9attr->mode,
 474                                                         p9attr->uid,
 475                                                         p9attr->gid,
 476                                                         p9attr->size,
 477                                                         p9attr->atime_sec,
 478                                                         p9attr->atime_nsec,
 479                                                         p9attr->mtime_sec,
 480                                                         p9attr->mtime_nsec);
 481                         }
 482                         break;
 483                 case '?':
 484                         if ((proto_version != p9_proto_2000u) &&
 485                                 (proto_version != p9_proto_2000L))
 486                                 return 0;
 487                         break;
 488                 default:
 489                         BUG();
 490                         break;
 491                 }
 492
 493                 if (errcode)
 494                         break;
 495         }
 496
 497         return errcode;
 498 }
 499
 500 int p9pdu_readf(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
 501 {
 502         va_list ap;
 503         int ret;
 504
 505         va_start(ap, fmt);
 506         ret = p9pdu_vreadf(pdu, proto_version, fmt, ap);
 507         va_end(ap);
 508
 509         return ret;
 510 }
 511
 512 static int
 513 p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
 514 {
 515         va_list ap;
 516         int ret;
 517
 518         va_start(ap, fmt);
 519         ret = p9pdu_vwritef(pdu, proto_version, fmt, ap);
 520         va_end(ap);
 521
 522         return ret;
 523 }
 524
 525 int p9stat_read(struct p9_client *clnt, char *buf, int len, struct p9_wstat *st)
 526 {
 527         struct p9_fcall fake_pdu;
 528         int ret;
 529
 530         fake_pdu.size = len;
 531         fake_pdu.capacity = len;
 532         fake_pdu.sdata = buf;
 533         fake_pdu.offset = 0;
 534
 535         ret = p9pdu_readf(&fake_pdu, clnt->proto_version, "S", st);
 536         if (ret) {
 537                 P9_DPRINTK(P9_DEBUG_9P, "<<< p9stat_read failed: %d\n", ret);
 538                 trace_9p_protocol_dump(clnt, &fake_pdu);
 539         }
 540
 541         return ret;
 542 }
 543 EXPORT_SYMBOL(p9stat_read);
 544
 545 int p9pdu_prepare(struct p9_fcall *pdu, int16_t tag, int8_t type)
 546 {
 547         pdu->id = type;
 548         return p9pdu_writef(pdu, 0, "dbw", 0, type, tag);
 549 }
 550
 551 int p9pdu_finalize(struct p9_client *clnt, struct p9_fcall *pdu)
 552 {
 553         int size = pdu->size;
 554         int err;
 555
 556         pdu->size = 0;
 557         err = p9pdu_writef(pdu, 0, "d", size);
 558         pdu->size = size;
 559
 560         trace_9p_protocol_dump(clnt, pdu);
 561         P9_DPRINTK(P9_DEBUG_9P, ">>> size=%d type: %d tag: %d\n", pdu->size,
 562                                                         pdu->id, pdu->tag);
 563
 564         return err;
 565 }
 566
 567 void p9pdu_reset(struct p9_fcall *pdu)
 568 {
 569         pdu->offset = 0;
 570         pdu->size = 0;
 571 }
 572
 573 int p9dirent_read(struct p9_client *clnt, char *buf, int len,
 574                   struct p9_dirent *dirent)
 575 {
 576         struct p9_fcall fake_pdu;
 577         int ret;
 578         char *nameptr;
 579
 580         fake_pdu.size = len;
 581         fake_pdu.capacity = len;
 582         fake_pdu.sdata = buf;
 583         fake_pdu.offset = 0;
 584
 585         ret = p9pdu_readf(&fake_pdu, clnt->proto_version, "Qqbs", &dirent->qid,
 586                           &dirent->d_off, &dirent->d_type, &nameptr);
 587         if (ret) {
 588                 P9_DPRINTK(P9_DEBUG_9P, "<<< p9dirent_read failed: %d\n", ret);
 589                 trace_9p_protocol_dump(clnt, &fake_pdu);
 590                 goto out;
 591         }
 592
 593         strcpy(dirent->d_name, nameptr);
 594         kfree(nameptr);
 595
 596 out:
 597         return fake_pdu.offset;
 598 }
 599 EXPORT_SYMBOL(p9dirent_read);