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 static int
  41 p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...);
  42
  43 #ifdef CONFIG_NET_9P_DEBUG
  44 void
  45 p9pdu_dump(int way, struct p9_fcall *pdu)
  46 {
  47         int len = pdu->size;
  48
  49         if ((p9_debug_level & P9_DEBUG_VPKT) != P9_DEBUG_VPKT) {
  50                 if ((p9_debug_level & P9_DEBUG_PKT) == P9_DEBUG_PKT) {
  51                         if (len > 32)
  52                                 len = 32;
  53                 } else {
  54                         /* shouldn't happen */
  55                         return;
  56                 }
  57         }
  58
  59         if (way)
  60                 print_hex_dump_bytes("[9P] ", DUMP_PREFIX_OFFSET, pdu->sdata,
  61                                                                         len);
  62         else
  63                 print_hex_dump_bytes("]9P[ ", DUMP_PREFIX_OFFSET, pdu->sdata,
  64                                                                         len);
  65 }
  66 #else
  67 void
  68 p9pdu_dump(int way, struct p9_fcall *pdu)
  69 {
  70 }
  71 #endif
  72 EXPORT_SYMBOL(p9pdu_dump);
  73
  74 void p9stat_free(struct p9_wstat *stbuf)
  75 {
  76         kfree(stbuf->name);
  77         kfree(stbuf->uid);
  78         kfree(stbuf->gid);
  79         kfree(stbuf->muid);
  80         kfree(stbuf->extension);
  81 }
  82 EXPORT_SYMBOL(p9stat_free);
  83
  84 size_t pdu_read(struct p9_fcall *pdu, void *data, size_t size)
  85 {
  86         size_t len = min(pdu->size - pdu->offset, size);
  87         memcpy(data, &pdu->sdata[pdu->offset], len);
  88         pdu->offset += len;
  89         return size - len;
  90 }
  91
  92 static size_t pdu_write(struct p9_fcall *pdu, const void *data, size_t size)
  93 {
  94         size_t len = min(pdu->capacity - pdu->size, size);
  95         memcpy(&pdu->sdata[pdu->size], data, len);
  96         pdu->size += len;
  97         return size - len;
  98 }
  99
 100 static size_t
 101 pdu_write_u(struct p9_fcall *pdu, const char __user *udata, size_t size)
 102 {
 103         size_t len = min(pdu->capacity - pdu->size, size);
 104         if (copy_from_user(&pdu->sdata[pdu->size], udata, len))
 105                 len = 0;
 106
 107         pdu->size += len;
 108         return size - len;
 109 }
 110
 111 /*
 112         b - int8_t
 113         w - int16_t
 114         d - int32_t
 115         q - int64_t
 116         s - string
 117         S - stat
 118         Q - qid
 119         D - data blob (int32_t size followed by void *, results are not freed)
 120         T - array of strings (int16_t count, followed by strings)
 121         R - array of qids (int16_t count, followed by qids)
 122         A - stat for 9p2000.L (p9_stat_dotl)
 123         ? - if optional = 1, continue parsing
 124 */
 125
 126 static int
 127 p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt,
 128         va_list ap)
 129 {
 130         const char *ptr;
 131         int errcode = 0;
 132
 133         for (ptr = fmt; *ptr; ptr++) {
 134                 switch (*ptr) {
 135                 case 'b':{
 136                                 int8_t *val = va_arg(ap, int8_t *);
 137                                 if (pdu_read(pdu, val, sizeof(*val))) {
 138                                         errcode = -EFAULT;
 139                                         break;
 140                                 }
 141                         }
 142                         break;
 143                 case 'w':{
 144                                 int16_t *val = va_arg(ap, int16_t *);
 145                                 __le16 le_val;
 146                                 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
 147                                         errcode = -EFAULT;
 148                                         break;
 149                                 }
 150                                 *val = le16_to_cpu(le_val);
 151                         }
 152                         break;
 153                 case 'd':{
 154                                 int32_t *val = va_arg(ap, int32_t *);
 155                                 __le32 le_val;
 156                                 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
 157                                         errcode = -EFAULT;
 158                                         break;
 159                                 }
 160                                 *val = le32_to_cpu(le_val);
 161                         }
 162                         break;
 163                 case 'q':{
 164                                 int64_t *val = va_arg(ap, int64_t *);
 165                                 __le64 le_val;
 166                                 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
 167                                         errcode = -EFAULT;
 168                                         break;
 169                                 }
 170                                 *val = le64_to_cpu(le_val);
 171                         }
 172                         break;
 173                 case 's':{
 174                                 char **sptr = va_arg(ap, char **);
 175                                 uint16_t len;
 176
 177                                 errcode = p9pdu_readf(pdu, proto_version,
 178                                                                 "w", &len);
 179                                 if (errcode)
 180                                         break;
 181
 182                                 *sptr = kmalloc(len + 1, GFP_NOFS);
 183                                 if (*sptr == NULL) {
 184                                         errcode = -EFAULT;
 185                                         break;
 186                                 }
 187                                 if (pdu_read(pdu, *sptr, len)) {
 188                                         errcode = -EFAULT;
 189                                         kfree(*sptr);
 190                                         *sptr = NULL;
 191                                 } else
 192                                         (*sptr)[len] = 0;
 193                         }
 194                         break;
 195                 case 'Q':{
 196                                 struct p9_qid *qid =
 197                                     va_arg(ap, struct p9_qid *);
 198
 199                                 errcode = p9pdu_readf(pdu, proto_version, "bdq",
 200                                                       &qid->type, &qid->version,
 201                                                       &qid->path);
 202                         }
 203                         break;
 204                 case 'S':{
 205                                 struct p9_wstat *stbuf =
 206                                     va_arg(ap, struct p9_wstat *);
 207
 208                                 memset(stbuf, 0, sizeof(struct p9_wstat));
 209                                 stbuf->n_uid = stbuf->n_gid = stbuf->n_muid =
 210                                                                         -1;
 211                                 errcode =
 212                                     p9pdu_readf(pdu, proto_version,
 213                                                 "wwdQdddqssss?sddd",
 214                                                 &stbuf->size, &stbuf->type,
 215                                                 &stbuf->dev, &stbuf->qid,
 216                                                 &stbuf->mode, &stbuf->atime,
 217                                                 &stbuf->mtime, &stbuf->length,
 218                                                 &stbuf->name, &stbuf->uid,
 219                                                 &stbuf->gid, &stbuf->muid,
 220                                                 &stbuf->extension,
 221                                                 &stbuf->n_uid, &stbuf->n_gid,
 222                                                 &stbuf->n_muid);
 223                                 if (errcode)
 224                                         p9stat_free(stbuf);
 225                         }
 226                         break;
 227                 case 'D':{
 228                                 uint32_t *count = va_arg(ap, uint32_t *);
 229                                 void **data = va_arg(ap, void **);
 230
 231                                 errcode =
 232                                     p9pdu_readf(pdu, proto_version, "d", count);
 233                                 if (!errcode) {
 234                                         *count =
 235                                             min_t(uint32_t, *count,
 236                                                   pdu->size - pdu->offset);
 237                                         *data = &pdu->sdata[pdu->offset];
 238                                 }
 239                         }
 240                         break;
 241                 case 'T':{
 242                                 uint16_t *nwname = va_arg(ap, uint16_t *);
 243                                 char ***wnames = va_arg(ap, char ***);
 244
 245                                 errcode = p9pdu_readf(pdu, proto_version,
 246                                                                 "w", nwname);
 247                                 if (!errcode) {
 248                                         *wnames =
 249                                             kmalloc(sizeof(char *) * *nwname,
 250                                                     GFP_NOFS);
 251                                         if (!*wnames)
 252                                                 errcode = -ENOMEM;
 253                                 }
 254
 255                                 if (!errcode) {
 256                                         int i;
 257
 258                                         for (i = 0; i < *nwname; i++) {
 259                                                 errcode =
 260                                                     p9pdu_readf(pdu,
 261                                                                 proto_version,
 262                                                                 "s",
 263                                                                 &(*wnames)[i]);
 264                                                 if (errcode)
 265                                                         break;
 266                                         }
 267                                 }
 268
 269                                 if (errcode) {
 270                                         if (*wnames) {
 271                                                 int i;
 272
 273                                                 for (i = 0; i < *nwname; i++)
 274                                                         kfree((*wnames)[i]);
 275                                         }
 276                                         kfree(*wnames);
 277                                         *wnames = NULL;
 278                                 }
 279                         }
 280                         break;
 281                 case 'R':{
 282                                 int16_t *nwqid = va_arg(ap, int16_t *);
 283                                 struct p9_qid **wqids =
 284                                     va_arg(ap, struct p9_qid **);
 285
 286                                 *wqids = NULL;
 287
 288                                 errcode =
 289                                     p9pdu_readf(pdu, proto_version, "w", nwqid);
 290                                 if (!errcode) {
 291                                         *wqids =
 292                                             kmalloc(*nwqid *
 293                                                     sizeof(struct p9_qid),
 294                                                     GFP_NOFS);
 295                                         if (*wqids == NULL)
 296                                                 errcode = -ENOMEM;
 297                                 }
 298
 299                                 if (!errcode) {
 300                                         int i;
 301
 302                                         for (i = 0; i < *nwqid; i++) {
 303                                                 errcode =
 304                                                     p9pdu_readf(pdu,
 305                                                                 proto_version,
 306                                                                 "Q",
 307                                                                 &(*wqids)[i]);
 308                                                 if (errcode)
 309                                                         break;
 310                                         }
 311                                 }
 312
 313                                 if (errcode) {
 314                                         kfree(*wqids);
 315                                         *wqids = NULL;
 316                                 }
 317                         }
 318                         break;
 319                 case 'A': {
 320                                 struct p9_stat_dotl *stbuf =
 321                                     va_arg(ap, struct p9_stat_dotl *);
 322
 323                                 memset(stbuf, 0, sizeof(struct p9_stat_dotl));
 324                                 errcode =
 325                                     p9pdu_readf(pdu, proto_version,
 326                                         "qQdddqqqqqqqqqqqqqqq",
 327                                         &stbuf->st_result_mask,
 328                                         &stbuf->qid,
 329                                         &stbuf->st_mode,
 330                                         &stbuf->st_uid, &stbuf->st_gid,
 331                                         &stbuf->st_nlink,
 332                                         &stbuf->st_rdev, &stbuf->st_size,
 333                                         &stbuf->st_blksize, &stbuf->st_blocks,
 334                                         &stbuf->st_atime_sec,
 335                                         &stbuf->st_atime_nsec,
 336                                         &stbuf->st_mtime_sec,
 337                                         &stbuf->st_mtime_nsec,
 338                                         &stbuf->st_ctime_sec,
 339                                         &stbuf->st_ctime_nsec,
 340                                         &stbuf->st_btime_sec,
 341                                         &stbuf->st_btime_nsec,
 342                                         &stbuf->st_gen,
 343                                         &stbuf->st_data_version);
 344                         }
 345                         break;
 346                 case '?':
 347                         if ((proto_version != p9_proto_2000u) &&
 348                                 (proto_version != p9_proto_2000L))
 349                                 return 0;
 350                         break;
 351                 default:
 352                         BUG();
 353                         break;
 354                 }
 355
 356                 if (errcode)
 357                         break;
 358         }
 359
 360         return errcode;
 361 }
 362
 363 int
 364 p9pdu_vwritef(struct p9_fcall *pdu, int proto_version, const char *fmt,
 365         va_list ap)
 366 {
 367         const char *ptr;
 368         int errcode = 0;
 369
 370         for (ptr = fmt; *ptr; ptr++) {
 371                 switch (*ptr) {
 372                 case 'b':{
 373                                 int8_t val = va_arg(ap, int);
 374                                 if (pdu_write(pdu, &val, sizeof(val)))
 375                                         errcode = -EFAULT;
 376                         }
 377                         break;
 378                 case 'w':{
 379                                 __le16 val = cpu_to_le16(va_arg(ap, int));
 380                                 if (pdu_write(pdu, &val, sizeof(val)))
 381                                         errcode = -EFAULT;
 382                         }
 383                         break;
 384                 case 'd':{
 385                                 __le32 val = cpu_to_le32(va_arg(ap, int32_t));
 386                                 if (pdu_write(pdu, &val, sizeof(val)))
 387                                         errcode = -EFAULT;
 388                         }
 389                         break;
 390                 case 'q':{
 391                                 __le64 val = cpu_to_le64(va_arg(ap, int64_t));
 392                                 if (pdu_write(pdu, &val, sizeof(val)))
 393                                         errcode = -EFAULT;
 394                         }
 395                         break;
 396                 case 's':{
 397                                 const char *sptr = va_arg(ap, const char *);
 398                                 uint16_t len = 0;
 399                                 if (sptr)
 400                                         len = min_t(uint16_t, strlen(sptr),
 401                                                                 USHRT_MAX);
 402
 403                                 errcode = p9pdu_writef(pdu, proto_version,
 404                                                                 "w", len);
 405                                 if (!errcode && pdu_write(pdu, sptr, len))
 406                                         errcode = -EFAULT;
 407                         }
 408                         break;
 409                 case 'Q':{
 410                                 const struct p9_qid *qid =
 411                                     va_arg(ap, const struct p9_qid *);
 412                                 errcode =
 413                                     p9pdu_writef(pdu, proto_version, "bdq",
 414                                                  qid->type, qid->version,
 415                                                  qid->path);
 416                         } break;
 417                 case 'S':{
 418                                 const struct p9_wstat *stbuf =
 419                                     va_arg(ap, const struct p9_wstat *);
 420                                 errcode =
 421                                     p9pdu_writef(pdu, proto_version,
 422                                                  "wwdQdddqssss?sddd",
 423                                                  stbuf->size, stbuf->type,
 424                                                  stbuf->dev, &stbuf->qid,
 425                                                  stbuf->mode, stbuf->atime,
 426                                                  stbuf->mtime, stbuf->length,
 427                                                  stbuf->name, stbuf->uid,
 428                                                  stbuf->gid, stbuf->muid,
 429                                                  stbuf->extension, stbuf->n_uid,
 430                                                  stbuf->n_gid, stbuf->n_muid);
 431                         } break;
 432                 case 'D':{
 433                                 uint32_t count = va_arg(ap, uint32_t);
 434                                 const void *data = va_arg(ap, const void *);
 435
 436                                 errcode = p9pdu_writef(pdu, proto_version, "d",
 437                                                                         count);
 438                                 if (!errcode && pdu_write(pdu, data, count))
 439                                         errcode = -EFAULT;
 440                         }
 441                         break;
 442                 case 'U':{
 443                                 int32_t count = va_arg(ap, int32_t);
 444                                 const char __user *udata =
 445                                                 va_arg(ap, const void __user *);
 446                                 errcode = p9pdu_writef(pdu, proto_version, "d",
 447                                                                         count);
 448                                 if (!errcode && pdu_write_u(pdu, udata, 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                                 int16_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                                                         "ddddqqqqq",
 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(char *buf, int len, struct p9_wstat *st, int proto_version)
 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, proto_version, "S", st);
 565         if (ret) {
 566                 P9_DPRINTK(P9_DEBUG_9P, "<<< p9stat_read failed: %d\n", ret);
 567                 P9_DUMP_PKT(0, &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_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         P9_DUMP_PKT(0, pdu);
 590         P9_DPRINTK(P9_DEBUG_9P, ">>> size=%d type: %d tag: %d\n", pdu->size,
 591                                                         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(char *buf, int len, struct p9_dirent *dirent,
 603                                                 int proto_version)
 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, proto_version, "Qqbs", &dirent->qid,
 615                         &dirent->d_off, &dirent->d_type, &nameptr);
 616         if (ret) {
 617                 P9_DPRINTK(P9_DEBUG_9P, "<<< p9dirent_read failed: %d\n", ret);
 618                 P9_DUMP_PKT(1, &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);