net/9p/protocol.c

   1 /*
   2  * net/9p/protocol.c
   3  *
   4  * 9P Protocol Support Code
   5  *
   6  *  Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
   7  *
   8  *  Base on code from Anthony Liguori <aliguori@us.ibm.com>
   9  *  Copyright (C) 2008 by IBM, Corp.
  10  *
  11  *  This program is free software; you can redistribute it and/or modify
  12  *  it under the terms of the GNU General Public License version 2
  13  *  as published by the Free Software Foundation.
  14  *
  15  *  This program is distributed in the hope that it will be useful,
  16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  *  GNU General Public License for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License
  21  *  along with this program; if not, write to:
  22  *  Free Software Foundation
  23  *  51 Franklin Street, Fifth Floor
  24  *  Boston, MA  02111-1301  USA
  25  *
  26  */
  27
  28 #include <linux/module.h>
  29 #include <linux/errno.h>
  30 #include <linux/kernel.h>
  31 #include <linux/uaccess.h>
  32 #include <linux/slab.h>
  33 #include <linux/sched.h>
  34 #include <linux/stddef.h>
  35 #include <linux/types.h>
  36 #include <linux/uio.h>
  37 #include <net/9p/9p.h>
  38 #include <net/9p/client.h>
  39 #include "protocol.h"
  40
  41 #include <trace/events/9p.h>
  42
  43 static int
  44 p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...);
  45
  46 void p9stat_free(struct p9_wstat *stbuf)
  47 {
  48         kfree(stbuf->name);
  49         kfree(stbuf->uid);
  50         kfree(stbuf->gid);
  51         kfree(stbuf->muid);
  52         kfree(stbuf->extension);
  53 }
  54 EXPORT_SYMBOL(p9stat_free);
  55
  56 size_t pdu_read(struct p9_fcall *pdu, void *data, size_t size)
  57 {
  58         size_t len = min(pdu->size - pdu->offset, size);
  59         memcpy(data, &pdu->sdata[pdu->offset], len);
  60         pdu->offset += len;
  61         return size - len;
  62 }
  63
  64 static size_t pdu_write(struct p9_fcall *pdu, const void *data, size_t size)
  65 {
  66         size_t len = min(pdu->capacity - pdu->size, size);
  67         memcpy(&pdu->sdata[pdu->size], data, len);
  68         pdu->size += len;
  69         return size - len;
  70 }
  71
  72 static size_t
  73 pdu_write_u(struct p9_fcall *pdu, struct iov_iter *from, size_t size)
  74 {
  75         size_t len = min(pdu->capacity - pdu->size, size);
  76         struct iov_iter i = *from;
  77         if (copy_from_iter(&pdu->sdata[pdu->size], len, &i) != len)
  78                 len = 0;
  79
  80         pdu->size += len;
  81         return size - len;
  82 }
  83
  84 /*
  85         b - int8_t
  86         w - int16_t
  87         d - int32_t
  88         q - int64_t
  89         s - string
  90         u - numeric uid
  91         g - numeric gid
  92         S - stat
  93         Q - qid
  94         D - data blob (int32_t size followed by void *, results are not freed)
  95         T - array of strings (int16_t count, followed by strings)
  96         R - array of qids (int16_t count, followed by qids)
  97         A - stat for 9p2000.L (p9_stat_dotl)
  98         ? - if optional = 1, continue parsing
  99 */
 100
 101 static int
 102 p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt,
 103         va_list ap)
 104 {
 105         const char *ptr;
 106         int errcode = 0;
 107
 108         for (ptr = fmt; *ptr; ptr++) {
 109                 switch (*ptr) {
 110                 case 'b':{
 111                                 int8_t *val = va_arg(ap, int8_t *);
 112                                 if (pdu_read(pdu, val, sizeof(*val))) {
 113                                         errcode = -EFAULT;
 114                                         break;
 115                                 }
 116                         }
 117                         break;
 118                 case 'w':{
 119                                 int16_t *val = va_arg(ap, int16_t *);
 120                                 __le16 le_val;
 121                                 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
 122                                         errcode = -EFAULT;
 123                                         break;
 124                                 }
 125                                 *val = le16_to_cpu(le_val);
 126                         }
 127                         break;
 128                 case 'd':{
 129                                 int32_t *val = va_arg(ap, int32_t *);
 130                                 __le32 le_val;
 131                                 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
 132                                         errcode = -EFAULT;
 133                                         break;
 134                                 }
 135                                 *val = le32_to_cpu(le_val);
 136                         }
 137                         break;
 138                 case 'q':{
 139                                 int64_t *val = va_arg(ap, int64_t *);
 140                                 __le64 le_val;
 141                                 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
 142                                         errcode = -EFAULT;
 143                                         break;
 144                                 }
 145                                 *val = le64_to_cpu(le_val);
 146                         }
 147                         break;
 148                 case 's':{
 149                                 char **sptr = va_arg(ap, char **);
 150                                 uint16_t len;
 151
 152                                 errcode = p9pdu_readf(pdu, proto_version,
 153                                                                 "w", &len);
 154                                 if (errcode)
 155                                         break;
 156
 157                                 *sptr = kmalloc(len + 1, GFP_NOFS);
 158                                 if (*sptr == NULL) {
 159                                         errcode = -EFAULT;
 160                                         break;
 161                                 }
 162                                 if (pdu_read(pdu, *sptr, len)) {
 163                                         errcode = -EFAULT;
 164                                         kfree(*sptr);
 165                                         *sptr = NULL;
 166                                 } else
 167                                         (*sptr)[len] = 0;
 168                         }
 169                         break;
 170                 case 'u': {
 171                                 kuid_t *uid = va_arg(ap, kuid_t *);
 172                                 __le32 le_val;
 173                                 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
 174                                         errcode = -EFAULT;
 175                                         break;
 176                                 }
 177                                 *uid = make_kuid(&init_user_ns,
 178                                                  le32_to_cpu(le_val));
 179                         } break;
 180                 case 'g': {
 181                                 kgid_t *gid = va_arg(ap, kgid_t *);
 182                                 __le32 le_val;
 183                                 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
 184                                         errcode = -EFAULT;
 185                                         break;
 186                                 }
 187                                 *gid = make_kgid(&init_user_ns,
 188                                                  le32_to_cpu(le_val));
 189                         } break;
 190                 case 'Q':{
 191                                 struct p9_qid *qid =
 192                                     va_arg(ap, struct p9_qid *);
 193
 194                                 errcode = p9pdu_readf(pdu, proto_version, "bdq",
 195                                                       &qid->type, &qid->version,
 196                                                       &qid->path);
 197                         }
 198                         break;
 199                 case 'S':{
 200                                 struct p9_wstat *stbuf =
 201                                     va_arg(ap, struct p9_wstat *);
 202
 203                                 memset(stbuf, 0, sizeof(struct p9_wstat));
 204                                 stbuf->n_uid = stbuf->n_muid = INVALID_UID;
 205                                 stbuf->n_gid = INVALID_GID;
 206
 207                                 errcode =
 208                                     p9pdu_readf(pdu, proto_version,
 209                                                 "wwdQdddqssss?sugu",
 210                                                 &stbuf->size, &stbuf->type,
 211                                                 &stbuf->dev, &stbuf->qid,
 212                                                 &stbuf->mode, &stbuf->atime,
 213                                                 &stbuf->mtime, &stbuf->length,
 214                                                 &stbuf->name, &stbuf->uid,
 215                                                 &stbuf->gid, &stbuf->muid,
 216                                                 &stbuf->extension,
 217                                                 &stbuf->n_uid, &stbuf->n_gid,
 218                                                 &stbuf->n_muid);
 219                                 if (errcode)
 220                                         p9stat_free(stbuf);
 221                         }
 222                         break;
 223                 case 'D':{
 224                                 uint32_t *count = va_arg(ap, uint32_t *);
 225                                 void **data = va_arg(ap, void **);
 226
 227                                 errcode =
 228                                     p9pdu_readf(pdu, proto_version, "d", count);
 229                                 if (!errcode) {
 230                                         *count =
 231                                             min_t(uint32_t, *count,
 232                                                   pdu->size - pdu->offset);
 233                                         *data = &pdu->sdata[pdu->offset];
 234                                 }
 235                         }
 236                         break;
 237                 case 'T':{
 238                                 uint16_t *nwname = va_arg(ap, uint16_t *);
 239                                 char ***wnames = va_arg(ap, char ***);
 240
 241                                 errcode = p9pdu_readf(pdu, proto_version,
 242                                                                 "w", nwname);
 243                                 if (!errcode) {
 244                                         *wnames =
 245                                             kmalloc(sizeof(char *) * *nwname,
 246                                                     GFP_NOFS);
 247                                         if (!*wnames)
 248                                                 errcode = -ENOMEM;
 249                                 }
 250
 251                                 if (!errcode) {
 252                                         int i;
 253
 254                                         for (i = 0; i < *nwname; i++) {
 255                                                 errcode =
 256                                                     p9pdu_readf(pdu,
 257                                                                 proto_version,
 258                                                                 "s",
 259                                                                 &(*wnames)[i]);
 260                                                 if (errcode)
 261                                                         break;
 262                                         }
 263                                 }
 264
 265                                 if (errcode) {
 266                                         if (*wnames) {
 267                                                 int i;
 268
 269                                                 for (i = 0; i < *nwname; i++)
 270                                                         kfree((*wnames)[i]);
 271                                         }
 272                                         kfree(*wnames);
 273                                         *wnames = NULL;
 274                                 }
 275                         }
 276                         break;
 277                 case 'R':{
 278                                 uint16_t *nwqid = va_arg(ap, uint16_t *);
 279                                 struct p9_qid **wqids =
 280                                     va_arg(ap, struct p9_qid **);
 281
 282                                 *wqids = NULL;
 283
 284                                 errcode =
 285                                     p9pdu_readf(pdu, proto_version, "w", nwqid);
 286                                 if (!errcode) {
 287                                         *wqids =
 288                                             kmalloc(*nwqid *
 289                                                     sizeof(struct p9_qid),
 290                                                     GFP_NOFS);
 291                                         if (*wqids == NULL)
 292                                                 errcode = -ENOMEM;
 293                                 }
 294
 295                                 if (!errcode) {
 296                                         int i;
 297
 298                                         for (i = 0; i < *nwqid; i++) {
 299                                                 errcode =
 300                                                     p9pdu_readf(pdu,
 301                                                                 proto_version,
 302                                                                 "Q",
 303                                                                 &(*wqids)[i]);
 304                                                 if (errcode)
 305                                                         break;
 306                                         }
 307                                 }
 308
 309                                 if (errcode) {
 310                                         kfree(*wqids);
 311                                         *wqids = NULL;
 312                                 }
 313                         }
 314                         break;
 315                 case 'A': {
 316                                 struct p9_stat_dotl *stbuf =
 317                                     va_arg(ap, struct p9_stat_dotl *);
 318
 319                                 memset(stbuf, 0, sizeof(struct p9_stat_dotl));
 320                                 errcode =
 321                                     p9pdu_readf(pdu, proto_version,
 322                                         "qQdugqqqqqqqqqqqqqqq",
 323                                         &stbuf->st_result_mask,
 324                                         &stbuf->qid,
 325                                         &stbuf->st_mode,
 326                                         &stbuf->st_uid, &stbuf->st_gid,
 327                                         &stbuf->st_nlink,
 328                                         &stbuf->st_rdev, &stbuf->st_size,
 329                                         &stbuf->st_blksize, &stbuf->st_blocks,
 330                                         &stbuf->st_atime_sec,
 331                                         &stbuf->st_atime_nsec,
 332                                         &stbuf->st_mtime_sec,
 333                                         &stbuf->st_mtime_nsec,
 334                                         &stbuf->st_ctime_sec,
 335                                         &stbuf->st_ctime_nsec,
 336                                         &stbuf->st_btime_sec,
 337                                         &stbuf->st_btime_nsec,
 338                                         &stbuf->st_gen,
 339                                         &stbuf->st_data_version);
 340                         }
 341                         break;
 342                 case '?':
 343                         if ((proto_version != p9_proto_2000u) &&
 344                                 (proto_version != p9_proto_2000L))
 345                                 return 0;
 346                         break;
 347                 default:
 348                         BUG();
 349                         break;
 350                 }
 351
 352                 if (errcode)
 353                         break;
 354         }
 355
 356         return errcode;
 357 }
 358
 359 int
 360 p9pdu_vwritef(struct p9_fcall *pdu, int proto_version, const char *fmt,
 361         va_list ap)
 362 {
 363         const char *ptr;
 364         int errcode = 0;
 365
 366         for (ptr = fmt; *ptr; ptr++) {
 367                 switch (*ptr) {
 368                 case 'b':{
 369                                 int8_t val = va_arg(ap, int);
 370                                 if (pdu_write(pdu, &val, sizeof(val)))
 371                                         errcode = -EFAULT;
 372                         }
 373                         break;
 374                 case 'w':{
 375                                 __le16 val = cpu_to_le16(va_arg(ap, int));
 376                                 if (pdu_write(pdu, &val, sizeof(val)))
 377                                         errcode = -EFAULT;
 378                         }
 379                         break;
 380                 case 'd':{
 381                                 __le32 val = cpu_to_le32(va_arg(ap, int32_t));
 382                                 if (pdu_write(pdu, &val, sizeof(val)))
 383                                         errcode = -EFAULT;
 384                         }
 385                         break;
 386                 case 'q':{
 387                                 __le64 val = cpu_to_le64(va_arg(ap, int64_t));
 388                                 if (pdu_write(pdu, &val, sizeof(val)))
 389                                         errcode = -EFAULT;
 390                         }
 391                         break;
 392                 case 's':{
 393                                 const char *sptr = va_arg(ap, const char *);
 394                                 uint16_t len = 0;
 395                                 if (sptr)
 396                                         len = min_t(size_t, strlen(sptr),
 397                                                                 USHRT_MAX);
 398
 399                                 errcode = p9pdu_writef(pdu, proto_version,
 400                                                                 "w", len);
 401                                 if (!errcode && pdu_write(pdu, sptr, len))
 402                                         errcode = -EFAULT;
 403                         }
 404                         break;
 405                 case 'u': {
 406                                 kuid_t uid = va_arg(ap, kuid_t);
 407                                 __le32 val = cpu_to_le32(
 408                                                 from_kuid(&init_user_ns, uid));
 409                                 if (pdu_write(pdu, &val, sizeof(val)))
 410                                         errcode = -EFAULT;
 411                         } break;
 412                 case 'g': {
 413                                 kgid_t gid = va_arg(ap, kgid_t);
 414                                 __le32 val = cpu_to_le32(
 415                                                 from_kgid(&init_user_ns, gid));
 416                                 if (pdu_write(pdu, &val, sizeof(val)))
 417                                         errcode = -EFAULT;
 418                         } break;
 419                 case 'Q':{
 420                                 const struct p9_qid *qid =
 421                                     va_arg(ap, const struct p9_qid *);
 422                                 errcode =
 423                                     p9pdu_writef(pdu, proto_version, "bdq",
 424                                                  qid->type, qid->version,
 425                                                  qid->path);
 426                         } break;
 427                 case 'S':{
 428                                 const struct p9_wstat *stbuf =
 429                                     va_arg(ap, const struct p9_wstat *);
 430                                 errcode =
 431                                     p9pdu_writef(pdu, proto_version,
 432                                                  "wwdQdddqssss?sugu",
 433                                                  stbuf->size, stbuf->type,
 434                                                  stbuf->dev, &stbuf->qid,
 435                                                  stbuf->mode, stbuf->atime,
 436                                                  stbuf->mtime, stbuf->length,
 437                                                  stbuf->name, stbuf->uid,
 438                                                  stbuf->gid, stbuf->muid,
 439                                                  stbuf->extension, stbuf->n_uid,
 440                                                  stbuf->n_gid, stbuf->n_muid);
 441                         } break;
 442                 case 'V':{
 443                                 uint32_t count = va_arg(ap, uint32_t);
 444                                 struct iov_iter *from =
 445                                                 va_arg(ap, struct iov_iter *);
 446                                 errcode = p9pdu_writef(pdu, proto_version, "d",
 447                                                                         count);
 448                                 if (!errcode && pdu_write_u(pdu, from, count))
 449                                         errcode = -EFAULT;
 450                         }
 451                         break;
 452                 case 'T':{
 453                                 uint16_t nwname = va_arg(ap, int);
 454                                 const char **wnames = va_arg(ap, const char **);
 455
 456                                 errcode = p9pdu_writef(pdu, proto_version, "w",
 457                                                                         nwname);
 458                                 if (!errcode) {
 459                                         int i;
 460
 461                                         for (i = 0; i < nwname; i++) {
 462                                                 errcode =
 463                                                     p9pdu_writef(pdu,
 464                                                                 proto_version,
 465                                                                  "s",
 466                                                                  wnames[i]);
 467                                                 if (errcode)
 468                                                         break;
 469                                         }
 470                                 }
 471                         }
 472                         break;
 473                 case 'R':{
 474                                 uint16_t nwqid = va_arg(ap, int);
 475                                 struct p9_qid *wqids =
 476                                     va_arg(ap, struct p9_qid *);
 477
 478                                 errcode = p9pdu_writef(pdu, proto_version, "w",
 479                                                                         nwqid);
 480                                 if (!errcode) {
 481                                         int i;
 482
 483                                         for (i = 0; i < nwqid; i++) {
 484                                                 errcode =
 485                                                     p9pdu_writef(pdu,
 486                                                                 proto_version,
 487                                                                  "Q",
 488                                                                  &wqids[i]);
 489                                                 if (errcode)
 490                                                         break;
 491                                         }
 492                                 }
 493                         }
 494                         break;
 495                 case 'I':{
 496                                 struct p9_iattr_dotl *p9attr = va_arg(ap,
 497                                                         struct p9_iattr_dotl *);
 498
 499                                 errcode = p9pdu_writef(pdu, proto_version,
 500                                                         "ddugqqqqq",
 501                                                         p9attr->valid,
 502                                                         p9attr->mode,
 503                                                         p9attr->uid,
 504                                                         p9attr->gid,
 505                                                         p9attr->size,
 506                                                         p9attr->atime_sec,
 507                                                         p9attr->atime_nsec,
 508                                                         p9attr->mtime_sec,
 509                                                         p9attr->mtime_nsec);
 510                         }
 511                         break;
 512                 case '?':
 513                         if ((proto_version != p9_proto_2000u) &&
 514                                 (proto_version != p9_proto_2000L))
 515                                 return 0;
 516                         break;
 517                 default:
 518                         BUG();
 519                         break;
 520                 }
 521
 522                 if (errcode)
 523                         break;
 524         }
 525
 526         return errcode;
 527 }
 528
 529 int p9pdu_readf(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
 530 {
 531         va_list ap;
 532         int ret;
 533
 534         va_start(ap, fmt);
 535         ret = p9pdu_vreadf(pdu, proto_version, fmt, ap);
 536         va_end(ap);
 537
 538         return ret;
 539 }
 540
 541 static int
 542 p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
 543 {
 544         va_list ap;
 545         int ret;
 546
 547         va_start(ap, fmt);
 548         ret = p9pdu_vwritef(pdu, proto_version, fmt, ap);
 549         va_end(ap);
 550
 551         return ret;
 552 }
 553
 554 int p9stat_read(struct p9_client *clnt, char *buf, int len, struct p9_wstat *st)
 555 {
 556         struct p9_fcall fake_pdu;
 557         int ret;
 558
 559         fake_pdu.size = len;
 560         fake_pdu.capacity = len;
 561         fake_pdu.sdata = buf;
 562         fake_pdu.offset = 0;
 563
 564         ret = p9pdu_readf(&fake_pdu, clnt->proto_version, "S", st);
 565         if (ret) {
 566                 p9_debug(P9_DEBUG_9P, "<<< p9stat_read failed: %d\n", ret);
 567                 trace_9p_protocol_dump(clnt, &fake_pdu);
 568         }
 569
 570         return ret;
 571 }
 572 EXPORT_SYMBOL(p9stat_read);
 573
 574 int p9pdu_prepare(struct p9_fcall *pdu, int16_t tag, int8_t type)
 575 {
 576         pdu->id = type;
 577         return p9pdu_writef(pdu, 0, "dbw", 0, type, tag);
 578 }
 579
 580 int p9pdu_finalize(struct p9_client *clnt, struct p9_fcall *pdu)
 581 {
 582         int size = pdu->size;
 583         int err;
 584
 585         pdu->size = 0;
 586         err = p9pdu_writef(pdu, 0, "d", size);
 587         pdu->size = size;
 588
 589         trace_9p_protocol_dump(clnt, pdu);
 590         p9_debug(P9_DEBUG_9P, ">>> size=%d type: %d tag: %d\n",
 591                  pdu->size, pdu->id, pdu->tag);
 592
 593         return err;
 594 }
 595
 596 void p9pdu_reset(struct p9_fcall *pdu)
 597 {
 598         pdu->offset = 0;
 599         pdu->size = 0;
 600 }
 601
 602 int p9dirent_read(struct p9_client *clnt, char *buf, int len,
 603                   struct p9_dirent *dirent)
 604 {
 605         struct p9_fcall fake_pdu;
 606         int ret;
 607         char *nameptr;
 608
 609         fake_pdu.size = len;
 610         fake_pdu.capacity = len;
 611         fake_pdu.sdata = buf;
 612         fake_pdu.offset = 0;
 613
 614         ret = p9pdu_readf(&fake_pdu, clnt->proto_version, "Qqbs", &dirent->qid,
 615                           &dirent->d_off, &dirent->d_type, &nameptr);
 616         if (ret) {
 617                 p9_debug(P9_DEBUG_9P, "<<< p9dirent_read failed: %d\n", ret);
 618                 trace_9p_protocol_dump(clnt, &fake_pdu);
 619                 goto out;
 620         }
 621
 622         strcpy(dirent->d_name, nameptr);
 623         kfree(nameptr);
 624
 625 out:
 626         return fake_pdu.offset;
 627 }
 628 EXPORT_SYMBOL(p9dirent_read);