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 static 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 static size_t
 112 pdu_write_urw(struct p9_fcall *pdu, const char *kdata, const char __user *udata,
 113                 size_t size)
 114 {
 115         BUG_ON(pdu->size > P9_IOHDRSZ);
 116         pdu->pubuf = (char __user *)udata;
 117         pdu->pkbuf = (char *)kdata;
 118         pdu->pbuf_size = size;
 119         return 0;
 120 }
 121
 122 static size_t
 123 pdu_write_readdir(struct p9_fcall *pdu, const char *kdata, size_t size)
 124 {
 125         BUG_ON(pdu->size > P9_READDIRHDRSZ);
 126         pdu->pkbuf = (char *)kdata;
 127         pdu->pbuf_size = size;
 128         return 0;
 129 }
 130
 131 /*
 132         b - int8_t
 133         w - int16_t
 134         d - int32_t
 135         q - int64_t
 136         s - string
 137         S - stat
 138         Q - qid
 139         D - data blob (int32_t size followed by void *, results are not freed)
 140         T - array of strings (int16_t count, followed by strings)
 141         R - array of qids (int16_t count, followed by qids)
 142         A - stat for 9p2000.L (p9_stat_dotl)
 143         ? - if optional = 1, continue parsing
 144 */
 145
 146 static int
 147 p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt,
 148         va_list ap)
 149 {
 150         const char *ptr;
 151         int errcode = 0;
 152
 153         for (ptr = fmt; *ptr; ptr++) {
 154                 switch (*ptr) {
 155                 case 'b':{
 156                                 int8_t *val = va_arg(ap, int8_t *);
 157                                 if (pdu_read(pdu, val, sizeof(*val))) {
 158                                         errcode = -EFAULT;
 159                                         break;
 160                                 }
 161                         }
 162                         break;
 163                 case 'w':{
 164                                 int16_t *val = va_arg(ap, int16_t *);
 165                                 __le16 le_val;
 166                                 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
 167                                         errcode = -EFAULT;
 168                                         break;
 169                                 }
 170                                 *val = le16_to_cpu(le_val);
 171                         }
 172                         break;
 173                 case 'd':{
 174                                 int32_t *val = va_arg(ap, int32_t *);
 175                                 __le32 le_val;
 176                                 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
 177                                         errcode = -EFAULT;
 178                                         break;
 179                                 }
 180                                 *val = le32_to_cpu(le_val);
 181                         }
 182                         break;
 183                 case 'q':{
 184                                 int64_t *val = va_arg(ap, int64_t *);
 185                                 __le64 le_val;
 186                                 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
 187                                         errcode = -EFAULT;
 188                                         break;
 189                                 }
 190                                 *val = le64_to_cpu(le_val);
 191                         }
 192                         break;
 193                 case 's':{
 194                                 char **sptr = va_arg(ap, char **);
 195                                 uint16_t len;
 196
 197                                 errcode = p9pdu_readf(pdu, proto_version,
 198                                                                 "w", &len);
 199                                 if (errcode)
 200                                         break;
 201
 202                                 *sptr = kmalloc(len + 1, GFP_NOFS);
 203                                 if (*sptr == NULL) {
 204                                         errcode = -EFAULT;
 205                                         break;
 206                                 }
 207                                 if (pdu_read(pdu, *sptr, len)) {
 208                                         errcode = -EFAULT;
 209                                         kfree(*sptr);
 210                                         *sptr = NULL;
 211                                 } else
 212                                         (*sptr)[len] = 0;
 213                         }
 214                         break;
 215                 case 'Q':{
 216                                 struct p9_qid *qid =
 217                                     va_arg(ap, struct p9_qid *);
 218
 219                                 errcode = p9pdu_readf(pdu, proto_version, "bdq",
 220                                                       &qid->type, &qid->version,
 221                                                       &qid->path);
 222                         }
 223                         break;
 224                 case 'S':{
 225                                 struct p9_wstat *stbuf =
 226                                     va_arg(ap, struct p9_wstat *);
 227
 228                                 memset(stbuf, 0, sizeof(struct p9_wstat));
 229                                 stbuf->n_uid = stbuf->n_gid = stbuf->n_muid =
 230                                                                         -1;
 231                                 errcode =
 232                                     p9pdu_readf(pdu, proto_version,
 233                                                 "wwdQdddqssss?sddd",
 234                                                 &stbuf->size, &stbuf->type,
 235                                                 &stbuf->dev, &stbuf->qid,
 236                                                 &stbuf->mode, &stbuf->atime,
 237                                                 &stbuf->mtime, &stbuf->length,
 238                                                 &stbuf->name, &stbuf->uid,
 239                                                 &stbuf->gid, &stbuf->muid,
 240                                                 &stbuf->extension,
 241                                                 &stbuf->n_uid, &stbuf->n_gid,
 242                                                 &stbuf->n_muid);
 243                                 if (errcode)
 244                                         p9stat_free(stbuf);
 245                         }
 246                         break;
 247                 case 'D':{
 248                                 uint32_t *count = va_arg(ap, uint32_t *);
 249                                 void **data = va_arg(ap, void **);
 250
 251                                 errcode =
 252                                     p9pdu_readf(pdu, proto_version, "d", count);
 253                                 if (!errcode) {
 254                                         *count =
 255                                             min_t(uint32_t, *count,
 256                                                   pdu->size - pdu->offset);
 257                                         *data = &pdu->sdata[pdu->offset];
 258                                 }
 259                         }
 260                         break;
 261                 case 'T':{
 262                                 uint16_t *nwname = va_arg(ap, uint16_t *);
 263                                 char ***wnames = va_arg(ap, char ***);
 264
 265                                 errcode = p9pdu_readf(pdu, proto_version,
 266                                                                 "w", nwname);
 267                                 if (!errcode) {
 268                                         *wnames =
 269                                             kmalloc(sizeof(char *) * *nwname,
 270                                                     GFP_NOFS);
 271                                         if (!*wnames)
 272                                                 errcode = -ENOMEM;
 273                                 }
 274
 275                                 if (!errcode) {
 276                                         int i;
 277
 278                                         for (i = 0; i < *nwname; i++) {
 279                                                 errcode =
 280                                                     p9pdu_readf(pdu,
 281                                                                 proto_version,
 282                                                                 "s",
 283                                                                 &(*wnames)[i]);
 284                                                 if (errcode)
 285                                                         break;
 286                                         }
 287                                 }
 288
 289                                 if (errcode) {
 290                                         if (*wnames) {
 291                                                 int i;
 292
 293                                                 for (i = 0; i < *nwname; i++)
 294                                                         kfree((*wnames)[i]);
 295                                         }
 296                                         kfree(*wnames);
 297                                         *wnames = NULL;
 298                                 }
 299                         }
 300                         break;
 301                 case 'R':{
 302                                 int16_t *nwqid = va_arg(ap, int16_t *);
 303                                 struct p9_qid **wqids =
 304                                     va_arg(ap, struct p9_qid **);
 305
 306                                 *wqids = NULL;
 307
 308                                 errcode =
 309                                     p9pdu_readf(pdu, proto_version, "w", nwqid);
 310                                 if (!errcode) {
 311                                         *wqids =
 312                                             kmalloc(*nwqid *
 313                                                     sizeof(struct p9_qid),
 314                                                     GFP_NOFS);
 315                                         if (*wqids == NULL)
 316                                                 errcode = -ENOMEM;
 317                                 }
 318
 319                                 if (!errcode) {
 320                                         int i;
 321
 322                                         for (i = 0; i < *nwqid; i++) {
 323                                                 errcode =
 324                                                     p9pdu_readf(pdu,
 325                                                                 proto_version,
 326                                                                 "Q",
 327                                                                 &(*wqids)[i]);
 328                                                 if (errcode)
 329                                                         break;
 330                                         }
 331                                 }
 332
 333                                 if (errcode) {
 334                                         kfree(*wqids);
 335                                         *wqids = NULL;
 336                                 }
 337                         }
 338                         break;
 339                 case 'A': {
 340                                 struct p9_stat_dotl *stbuf =
 341                                     va_arg(ap, struct p9_stat_dotl *);
 342
 343                                 memset(stbuf, 0, sizeof(struct p9_stat_dotl));
 344                                 errcode =
 345                                     p9pdu_readf(pdu, proto_version,
 346                                         "qQdddqqqqqqqqqqqqqqq",
 347                                         &stbuf->st_result_mask,
 348                                         &stbuf->qid,
 349                                         &stbuf->st_mode,
 350                                         &stbuf->st_uid, &stbuf->st_gid,
 351                                         &stbuf->st_nlink,
 352                                         &stbuf->st_rdev, &stbuf->st_size,
 353                                         &stbuf->st_blksize, &stbuf->st_blocks,
 354                                         &stbuf->st_atime_sec,
 355                                         &stbuf->st_atime_nsec,
 356                                         &stbuf->st_mtime_sec,
 357                                         &stbuf->st_mtime_nsec,
 358                                         &stbuf->st_ctime_sec,
 359                                         &stbuf->st_ctime_nsec,
 360                                         &stbuf->st_btime_sec,
 361                                         &stbuf->st_btime_nsec,
 362                                         &stbuf->st_gen,
 363                                         &stbuf->st_data_version);
 364                         }
 365                         break;
 366                 case '?':
 367                         if ((proto_version != p9_proto_2000u) &&
 368                                 (proto_version != p9_proto_2000L))
 369                                 return 0;
 370                         break;
 371                 default:
 372                         BUG();
 373                         break;
 374                 }
 375
 376                 if (errcode)
 377                         break;
 378         }
 379
 380         return errcode;
 381 }
 382
 383 int
 384 p9pdu_vwritef(struct p9_fcall *pdu, int proto_version, const char *fmt,
 385         va_list ap)
 386 {
 387         const char *ptr;
 388         int errcode = 0;
 389
 390         for (ptr = fmt; *ptr; ptr++) {
 391                 switch (*ptr) {
 392                 case 'b':{
 393                                 int8_t val = va_arg(ap, int);
 394                                 if (pdu_write(pdu, &val, sizeof(val)))
 395                                         errcode = -EFAULT;
 396                         }
 397                         break;
 398                 case 'w':{
 399                                 __le16 val = cpu_to_le16(va_arg(ap, int));
 400                                 if (pdu_write(pdu, &val, sizeof(val)))
 401                                         errcode = -EFAULT;
 402                         }
 403                         break;
 404                 case 'd':{
 405                                 __le32 val = cpu_to_le32(va_arg(ap, int32_t));
 406                                 if (pdu_write(pdu, &val, sizeof(val)))
 407                                         errcode = -EFAULT;
 408                         }
 409                         break;
 410                 case 'q':{
 411                                 __le64 val = cpu_to_le64(va_arg(ap, int64_t));
 412                                 if (pdu_write(pdu, &val, sizeof(val)))
 413                                         errcode = -EFAULT;
 414                         }
 415                         break;
 416                 case 's':{
 417                                 const char *sptr = va_arg(ap, const char *);
 418                                 uint16_t len = 0;
 419                                 if (sptr)
 420                                         len = min_t(uint16_t, strlen(sptr),
 421                                                                 USHRT_MAX);
 422
 423                                 errcode = p9pdu_writef(pdu, proto_version,
 424                                                                 "w", len);
 425                                 if (!errcode && pdu_write(pdu, sptr, len))
 426                                         errcode = -EFAULT;
 427                         }
 428                         break;
 429                 case 'Q':{
 430                                 const struct p9_qid *qid =
 431                                     va_arg(ap, const struct p9_qid *);
 432                                 errcode =
 433                                     p9pdu_writef(pdu, proto_version, "bdq",
 434                                                  qid->type, qid->version,
 435                                                  qid->path);
 436                         } break;
 437                 case 'S':{
 438                                 const struct p9_wstat *stbuf =
 439                                     va_arg(ap, const struct p9_wstat *);
 440                                 errcode =
 441                                     p9pdu_writef(pdu, proto_version,
 442                                                  "wwdQdddqssss?sddd",
 443                                                  stbuf->size, stbuf->type,
 444                                                  stbuf->dev, &stbuf->qid,
 445                                                  stbuf->mode, stbuf->atime,
 446                                                  stbuf->mtime, stbuf->length,
 447                                                  stbuf->name, stbuf->uid,
 448                                                  stbuf->gid, stbuf->muid,
 449                                                  stbuf->extension, stbuf->n_uid,
 450                                                  stbuf->n_gid, stbuf->n_muid);
 451                         } break;
 452                 case 'D':{
 453                                 uint32_t count = va_arg(ap, uint32_t);
 454                                 const void *data = va_arg(ap, const void *);
 455
 456                                 errcode = p9pdu_writef(pdu, proto_version, "d",
 457                                                                         count);
 458                                 if (!errcode && pdu_write(pdu, data, count))
 459                                         errcode = -EFAULT;
 460                         }
 461                         break;
 462                 case 'E':{
 463                                  int32_t cnt = va_arg(ap, int32_t);
 464                                  const char *k = va_arg(ap, const void *);
 465                                  const char __user *u = va_arg(ap,
 466                                                         const void __user *);
 467                                  errcode = p9pdu_writef(pdu, proto_version, "d",
 468                                                  cnt);
 469                                  if (!errcode && pdu_write_urw(pdu, k, u, cnt))
 470                                         errcode = -EFAULT;
 471                          }
 472                          break;
 473                 case 'F':{
 474                                  int32_t cnt = va_arg(ap, int32_t);
 475                                  const char *k = va_arg(ap, const void *);
 476                                  errcode = p9pdu_writef(pdu, proto_version, "d",
 477                                                  cnt);
 478                                  if (!errcode && pdu_write_readdir(pdu, k, cnt))
 479                                         errcode = -EFAULT;
 480                          }
 481                          break;
 482                 case 'U':{
 483                                 int32_t count = va_arg(ap, int32_t);
 484                                 const char __user *udata =
 485                                                 va_arg(ap, const void __user *);
 486                                 errcode = p9pdu_writef(pdu, proto_version, "d",
 487                                                                         count);
 488                                 if (!errcode && pdu_write_u(pdu, udata, count))
 489                                         errcode = -EFAULT;
 490                         }
 491                         break;
 492                 case 'T':{
 493                                 uint16_t nwname = va_arg(ap, int);
 494                                 const char **wnames = va_arg(ap, const char **);
 495
 496                                 errcode = p9pdu_writef(pdu, proto_version, "w",
 497                                                                         nwname);
 498                                 if (!errcode) {
 499                                         int i;
 500
 501                                         for (i = 0; i < nwname; i++) {
 502                                                 errcode =
 503                                                     p9pdu_writef(pdu,
 504                                                                 proto_version,
 505                                                                  "s",
 506                                                                  wnames[i]);
 507                                                 if (errcode)
 508                                                         break;
 509                                         }
 510                                 }
 511                         }
 512                         break;
 513                 case 'R':{
 514                                 int16_t nwqid = va_arg(ap, int);
 515                                 struct p9_qid *wqids =
 516                                     va_arg(ap, struct p9_qid *);
 517
 518                                 errcode = p9pdu_writef(pdu, proto_version, "w",
 519                                                                         nwqid);
 520                                 if (!errcode) {
 521                                         int i;
 522
 523                                         for (i = 0; i < nwqid; i++) {
 524                                                 errcode =
 525                                                     p9pdu_writef(pdu,
 526                                                                 proto_version,
 527                                                                  "Q",
 528                                                                  &wqids[i]);
 529                                                 if (errcode)
 530                                                         break;
 531                                         }
 532                                 }
 533                         }
 534                         break;
 535                 case 'I':{
 536                                 struct p9_iattr_dotl *p9attr = va_arg(ap,
 537                                                         struct p9_iattr_dotl *);
 538
 539                                 errcode = p9pdu_writef(pdu, proto_version,
 540                                                         "ddddqqqqq",
 541                                                         p9attr->valid,
 542                                                         p9attr->mode,
 543                                                         p9attr->uid,
 544                                                         p9attr->gid,
 545                                                         p9attr->size,
 546                                                         p9attr->atime_sec,
 547                                                         p9attr->atime_nsec,
 548                                                         p9attr->mtime_sec,
 549                                                         p9attr->mtime_nsec);
 550                         }
 551                         break;
 552                 case '?':
 553                         if ((proto_version != p9_proto_2000u) &&
 554                                 (proto_version != p9_proto_2000L))
 555                                 return 0;
 556                         break;
 557                 default:
 558                         BUG();
 559                         break;
 560                 }
 561
 562                 if (errcode)
 563                         break;
 564         }
 565
 566         return errcode;
 567 }
 568
 569 int p9pdu_readf(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
 570 {
 571         va_list ap;
 572         int ret;
 573
 574         va_start(ap, fmt);
 575         ret = p9pdu_vreadf(pdu, proto_version, fmt, ap);
 576         va_end(ap);
 577
 578         return ret;
 579 }
 580
 581 static int
 582 p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
 583 {
 584         va_list ap;
 585         int ret;
 586
 587         va_start(ap, fmt);
 588         ret = p9pdu_vwritef(pdu, proto_version, fmt, ap);
 589         va_end(ap);
 590
 591         return ret;
 592 }
 593
 594 int p9stat_read(char *buf, int len, struct p9_wstat *st, int proto_version)
 595 {
 596         struct p9_fcall fake_pdu;
 597         int ret;
 598
 599         fake_pdu.size = len;
 600         fake_pdu.capacity = len;
 601         fake_pdu.sdata = buf;
 602         fake_pdu.offset = 0;
 603
 604         ret = p9pdu_readf(&fake_pdu, proto_version, "S", st);
 605         if (ret) {
 606                 P9_DPRINTK(P9_DEBUG_9P, "<<< p9stat_read failed: %d\n", ret);
 607                 P9_DUMP_PKT(0, &fake_pdu);
 608         }
 609
 610         return ret;
 611 }
 612 EXPORT_SYMBOL(p9stat_read);
 613
 614 int p9pdu_prepare(struct p9_fcall *pdu, int16_t tag, int8_t type)
 615 {
 616         pdu->id = type;
 617         return p9pdu_writef(pdu, 0, "dbw", 0, type, tag);
 618 }
 619
 620 int p9pdu_finalize(struct p9_fcall *pdu)
 621 {
 622         int size = pdu->size;
 623         int err;
 624
 625         pdu->size = 0;
 626         err = p9pdu_writef(pdu, 0, "d", size);
 627         pdu->size = size;
 628
 629         P9_DUMP_PKT(0, pdu);
 630         P9_DPRINTK(P9_DEBUG_9P, ">>> size=%d type: %d tag: %d\n", pdu->size,
 631                                                         pdu->id, pdu->tag);
 632
 633         return err;
 634 }
 635
 636 void p9pdu_reset(struct p9_fcall *pdu)
 637 {
 638         pdu->offset = 0;
 639         pdu->size = 0;
 640         pdu->private = NULL;
 641         pdu->pubuf = NULL;
 642         pdu->pkbuf = NULL;
 643         pdu->pbuf_size = 0;
 644 }
 645
 646 int p9dirent_read(char *buf, int len, struct p9_dirent *dirent,
 647                                                 int proto_version)
 648 {
 649         struct p9_fcall fake_pdu;
 650         int ret;
 651         char *nameptr;
 652
 653         fake_pdu.size = len;
 654         fake_pdu.capacity = len;
 655         fake_pdu.sdata = buf;
 656         fake_pdu.offset = 0;
 657
 658         ret = p9pdu_readf(&fake_pdu, proto_version, "Qqbs", &dirent->qid,
 659                         &dirent->d_off, &dirent->d_type, &nameptr);
 660         if (ret) {
 661                 P9_DPRINTK(P9_DEBUG_9P, "<<< p9dirent_read failed: %d\n", ret);
 662                 P9_DUMP_PKT(1, &fake_pdu);
 663                 goto out;
 664         }
 665
 666         strcpy(dirent->d_name, nameptr);
 667         kfree(nameptr);
 668
 669 out:
 670         return fake_pdu.offset;
 671 }
 672 EXPORT_SYMBOL(p9dirent_read);