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   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/uaccess.h>
  31 #include <linux/sched.h>
  32 #include <linux/types.h>
  33 #include <net/9p/9p.h>
  34 #include <net/9p/client.h>
  35 #include "protocol.h"
  36
  37 #ifndef MIN
  38 #define MIN(a, b) (((a) < (b)) ? (a) : (b))
  39 #endif
  40
  41 #ifndef MAX
  42 #define MAX(a, b) (((a) > (b)) ? (a) : (b))
  43 #endif
  44
  45 #ifndef offset_of
  46 #define offset_of(type, memb) \
  47         ((unsigned long)(&((type *)0)->memb))
  48 #endif
  49 #ifndef container_of
  50 #define container_of(obj, type, memb) \
  51         ((type *)(((char *)obj) - offset_of(type, memb)))
  52 #endif
  53
  54 static int
  55 p9pdu_writef(struct p9_fcall *pdu, int optional, const char *fmt, ...);
  56
  57 #ifdef CONFIG_NET_9P_DEBUG
  58 void
  59 p9pdu_dump(int way, struct p9_fcall *pdu)
  60 {
  61         int i, n;
  62         u8 *data = pdu->sdata;
  63         int datalen = pdu->size;
  64         char buf[255];
  65         int buflen = 255;
  66
  67         i = n = 0;
  68         if (datalen > (buflen-16))
  69                 datalen = buflen-16;
  70         while (i < datalen) {
  71                 n += scnprintf(buf + n, buflen - n, "%02x ", data[i]);
  72                 if (i%4 == 3)
  73                         n += scnprintf(buf + n, buflen - n, " ");
  74                 if (i%32 == 31)
  75                         n += scnprintf(buf + n, buflen - n, "\n");
  76
  77                 i++;
  78         }
  79         n += scnprintf(buf + n, buflen - n, "\n");
  80
  81         if (way)
  82                 P9_DPRINTK(P9_DEBUG_PKT, "[[[(%d) %s\n", datalen, buf);
  83         else
  84                 P9_DPRINTK(P9_DEBUG_PKT, "]]](%d) %s\n", datalen, buf);
  85 }
  86 #else
  87 void
  88 p9pdu_dump(int way, struct p9_fcall *pdu)
  89 {
  90 }
  91 #endif
  92 EXPORT_SYMBOL(p9pdu_dump);
  93
  94 void p9stat_free(struct p9_wstat *stbuf)
  95 {
  96         kfree(stbuf->name);
  97         kfree(stbuf->uid);
  98         kfree(stbuf->gid);
  99         kfree(stbuf->muid);
 100         kfree(stbuf->extension);
 101 }
 102 EXPORT_SYMBOL(p9stat_free);
 103
 104 static size_t pdu_read(struct p9_fcall *pdu, void *data, size_t size)
 105 {
 106         size_t len = MIN(pdu->size - pdu->offset, size);
 107         memcpy(data, &pdu->sdata[pdu->offset], len);
 108         pdu->offset += len;
 109         return size - len;
 110 }
 111
 112 static size_t pdu_write(struct p9_fcall *pdu, const void *data, size_t size)
 113 {
 114         size_t len = MIN(pdu->capacity - pdu->size, size);
 115         memcpy(&pdu->sdata[pdu->size], data, len);
 116         pdu->size += len;
 117         return size - len;
 118 }
 119
 120 static size_t
 121 pdu_write_u(struct p9_fcall *pdu, const char __user *udata, size_t size)
 122 {
 123         size_t len = MIN(pdu->capacity - pdu->size, size);
 124         int err = copy_from_user(&pdu->sdata[pdu->size], udata, len);
 125         if (err)
 126                 printk(KERN_WARNING "pdu_write_u returning: %d\n", err);
 127
 128         pdu->size += len;
 129         return size - len;
 130 }
 131
 132 /*
 133         b - int8_t
 134         w - int16_t
 135         d - int32_t
 136         q - int64_t
 137         s - string
 138         S - stat
 139         Q - qid
 140         D - data blob (int32_t size followed by void *, results are not freed)
 141         T - array of strings (int16_t count, followed by strings)
 142         R - array of qids (int16_t count, followed by qids)
 143         ? - if optional = 1, continue parsing
 144 */
 145
 146 static int
 147 p9pdu_vreadf(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
 148 {
 149         const char *ptr;
 150         int errcode = 0;
 151
 152         for (ptr = fmt; *ptr; ptr++) {
 153                 switch (*ptr) {
 154                 case 'b':{
 155                                 int8_t *val = va_arg(ap, int8_t *);
 156                                 if (pdu_read(pdu, val, sizeof(*val))) {
 157                                         errcode = -EFAULT;
 158                                         break;
 159                                 }
 160                         }
 161                         break;
 162                 case 'w':{
 163                                 int16_t *val = va_arg(ap, int16_t *);
 164                                 __le16 le_val;
 165                                 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
 166                                         errcode = -EFAULT;
 167                                         break;
 168                                 }
 169                                 *val = le16_to_cpu(le_val);
 170                         }
 171                         break;
 172                 case 'd':{
 173                                 int32_t *val = va_arg(ap, int32_t *);
 174                                 __le32 le_val;
 175                                 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
 176                                         errcode = -EFAULT;
 177                                         break;
 178                                 }
 179                                 *val = le32_to_cpu(le_val);
 180                         }
 181                         break;
 182                 case 'q':{
 183                                 int64_t *val = va_arg(ap, int64_t *);
 184                                 __le64 le_val;
 185                                 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
 186                                         errcode = -EFAULT;
 187                                         break;
 188                                 }
 189                                 *val = le64_to_cpu(le_val);
 190                         }
 191                         break;
 192                 case 's':{
 193                                 char **sptr = va_arg(ap, char **);
 194                                 int16_t len;
 195                                 int size;
 196
 197                                 errcode = p9pdu_readf(pdu, optional, "w", &len);
 198                                 if (errcode)
 199                                         break;
 200
 201                                 size = MAX(len, 0);
 202
 203                                 *sptr = kmalloc(size + 1, GFP_KERNEL);
 204                                 if (*sptr == NULL) {
 205                                         errcode = -EFAULT;
 206                                         break;
 207                                 }
 208                                 if (pdu_read(pdu, *sptr, size)) {
 209                                         errcode = -EFAULT;
 210                                         kfree(*sptr);
 211                                         *sptr = NULL;
 212                                 } else
 213                                         (*sptr)[size] = 0;
 214                         }
 215                         break;
 216                 case 'Q':{
 217                                 struct p9_qid *qid =
 218                                     va_arg(ap, struct p9_qid *);
 219
 220                                 errcode = p9pdu_readf(pdu, optional, "bdq",
 221                                                       &qid->type, &qid->version,
 222                                                       &qid->path);
 223                         }
 224                         break;
 225                 case 'S':{
 226                                 struct p9_wstat *stbuf =
 227                                     va_arg(ap, struct p9_wstat *);
 228
 229                                 memset(stbuf, 0, sizeof(struct p9_wstat));
 230                                 stbuf->n_uid = stbuf->n_gid = stbuf->n_muid =
 231                                                                         -1;
 232                                 errcode =
 233                                     p9pdu_readf(pdu, optional,
 234                                                 "wwdQdddqssss?sddd",
 235                                                 &stbuf->size, &stbuf->type,
 236                                                 &stbuf->dev, &stbuf->qid,
 237                                                 &stbuf->mode, &stbuf->atime,
 238                                                 &stbuf->mtime, &stbuf->length,
 239                                                 &stbuf->name, &stbuf->uid,
 240                                                 &stbuf->gid, &stbuf->muid,
 241                                                 &stbuf->extension,
 242                                                 &stbuf->n_uid, &stbuf->n_gid,
 243                                                 &stbuf->n_muid);
 244                                 if (errcode)
 245                                         p9stat_free(stbuf);
 246                         }
 247                         break;
 248                 case 'D':{
 249                                 int32_t *count = va_arg(ap, int32_t *);
 250                                 void **data = va_arg(ap, void **);
 251
 252                                 errcode =
 253                                     p9pdu_readf(pdu, optional, "d", count);
 254                                 if (!errcode) {
 255                                         *count =
 256                                             MIN(*count,
 257                                                 pdu->size - pdu->offset);
 258                                         *data = &pdu->sdata[pdu->offset];
 259                                 }
 260                         }
 261                         break;
 262                 case 'T':{
 263                                 int16_t *nwname = va_arg(ap, int16_t *);
 264                                 char ***wnames = va_arg(ap, char ***);
 265
 266                                 errcode =
 267                                     p9pdu_readf(pdu, optional, "w", nwname);
 268                                 if (!errcode) {
 269                                         *wnames =
 270                                             kmalloc(sizeof(char *) * *nwname,
 271                                                     GFP_KERNEL);
 272                                         if (!*wnames)
 273                                                 errcode = -ENOMEM;
 274                                 }
 275
 276                                 if (!errcode) {
 277                                         int i;
 278
 279                                         for (i = 0; i < *nwname; i++) {
 280                                                 errcode =
 281                                                     p9pdu_readf(pdu, optional,
 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, optional, "w", nwqid);
 310                                 if (!errcode) {
 311                                         *wqids =
 312                                             kmalloc(*nwqid *
 313                                                     sizeof(struct p9_qid),
 314                                                     GFP_KERNEL);
 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, optional,
 325                                                                 "Q",
 326                                                                 &(*wqids)[i]);
 327                                                 if (errcode)
 328                                                         break;
 329                                         }
 330                                 }
 331
 332                                 if (errcode) {
 333                                         kfree(*wqids);
 334                                         *wqids = NULL;
 335                                 }
 336                         }
 337                         break;
 338                 case '?':
 339                         if (!optional)
 340                                 return 0;
 341                         break;
 342                 default:
 343                         BUG();
 344                         break;
 345                 }
 346
 347                 if (errcode)
 348                         break;
 349         }
 350
 351         return errcode;
 352 }
 353
 354 int
 355 p9pdu_vwritef(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
 356 {
 357         const char *ptr;
 358         int errcode = 0;
 359
 360         for (ptr = fmt; *ptr; ptr++) {
 361                 switch (*ptr) {
 362                 case 'b':{
 363                                 int8_t val = va_arg(ap, int);
 364                                 if (pdu_write(pdu, &val, sizeof(val)))
 365                                         errcode = -EFAULT;
 366                         }
 367                         break;
 368                 case 'w':{
 369                                 __le16 val = cpu_to_le16(va_arg(ap, int));
 370                                 if (pdu_write(pdu, &val, sizeof(val)))
 371                                         errcode = -EFAULT;
 372                         }
 373                         break;
 374                 case 'd':{
 375                                 __le32 val = cpu_to_le32(va_arg(ap, int32_t));
 376                                 if (pdu_write(pdu, &val, sizeof(val)))
 377                                         errcode = -EFAULT;
 378                         }
 379                         break;
 380                 case 'q':{
 381                                 __le64 val = cpu_to_le64(va_arg(ap, int64_t));
 382                                 if (pdu_write(pdu, &val, sizeof(val)))
 383                                         errcode = -EFAULT;
 384                         }
 385                         break;
 386                 case 's':{
 387                                 const char *sptr = va_arg(ap, const char *);
 388                                 int16_t len = 0;
 389                                 if (sptr)
 390                                         len = MIN(strlen(sptr), USHORT_MAX);
 391
 392                                 errcode = p9pdu_writef(pdu, optional, "w", len);
 393                                 if (!errcode && pdu_write(pdu, sptr, len))
 394                                         errcode = -EFAULT;
 395                         }
 396                         break;
 397                 case 'Q':{
 398                                 const struct p9_qid *qid =
 399                                     va_arg(ap, const struct p9_qid *);
 400                                 errcode =
 401                                     p9pdu_writef(pdu, optional, "bdq",
 402                                                  qid->type, qid->version,
 403                                                  qid->path);
 404                         } break;
 405                 case 'S':{
 406                                 const struct p9_wstat *stbuf =
 407                                     va_arg(ap, const struct p9_wstat *);
 408                                 errcode =
 409                                     p9pdu_writef(pdu, optional,
 410                                                  "wwdQdddqssss?sddd",
 411                                                  stbuf->size, stbuf->type,
 412                                                  stbuf->dev, &stbuf->qid,
 413                                                  stbuf->mode, stbuf->atime,
 414                                                  stbuf->mtime, stbuf->length,
 415                                                  stbuf->name, stbuf->uid,
 416                                                  stbuf->gid, stbuf->muid,
 417                                                  stbuf->extension, stbuf->n_uid,
 418                                                  stbuf->n_gid, stbuf->n_muid);
 419                         } break;
 420                 case 'D':{
 421                                 int32_t count = va_arg(ap, int32_t);
 422                                 const void *data = va_arg(ap, const void *);
 423
 424                                 errcode =
 425                                     p9pdu_writef(pdu, optional, "d", count);
 426                                 if (!errcode && pdu_write(pdu, data, count))
 427                                         errcode = -EFAULT;
 428                         }
 429                         break;
 430                 case 'U':{
 431                                 int32_t count = va_arg(ap, int32_t);
 432                                 const char __user *udata =
 433                                                 va_arg(ap, const void __user *);
 434                                 errcode =
 435                                     p9pdu_writef(pdu, optional, "d", count);
 436                                 if (!errcode && pdu_write_u(pdu, udata, count))
 437                                         errcode = -EFAULT;
 438                         }
 439                         break;
 440                 case 'T':{
 441                                 int16_t nwname = va_arg(ap, int);
 442                                 const char **wnames = va_arg(ap, const char **);
 443
 444                                 errcode =
 445                                     p9pdu_writef(pdu, optional, "w", nwname);
 446                                 if (!errcode) {
 447                                         int i;
 448
 449                                         for (i = 0; i < nwname; i++) {
 450                                                 errcode =
 451                                                     p9pdu_writef(pdu, optional,
 452                                                                  "s",
 453                                                                  wnames[i]);
 454                                                 if (errcode)
 455                                                         break;
 456                                         }
 457                                 }
 458                         }
 459                         break;
 460                 case 'R':{
 461                                 int16_t nwqid = va_arg(ap, int);
 462                                 struct p9_qid *wqids =
 463                                     va_arg(ap, struct p9_qid *);
 464
 465                                 errcode =
 466                                     p9pdu_writef(pdu, optional, "w", nwqid);
 467                                 if (!errcode) {
 468                                         int i;
 469
 470                                         for (i = 0; i < nwqid; i++) {
 471                                                 errcode =
 472                                                     p9pdu_writef(pdu, optional,
 473                                                                  "Q",
 474                                                                  &wqids[i]);
 475                                                 if (errcode)
 476                                                         break;
 477                                         }
 478                                 }
 479                         }
 480                         break;
 481                 case '?':
 482                         if (!optional)
 483                                 return 0;
 484                         break;
 485                 default:
 486                         BUG();
 487                         break;
 488                 }
 489
 490                 if (errcode)
 491                         break;
 492         }
 493
 494         return errcode;
 495 }
 496
 497 int p9pdu_readf(struct p9_fcall *pdu, int optional, const char *fmt, ...)
 498 {
 499         va_list ap;
 500         int ret;
 501
 502         va_start(ap, fmt);
 503         ret = p9pdu_vreadf(pdu, optional, fmt, ap);
 504         va_end(ap);
 505
 506         return ret;
 507 }
 508
 509 static int
 510 p9pdu_writef(struct p9_fcall *pdu, int optional, const char *fmt, ...)
 511 {
 512         va_list ap;
 513         int ret;
 514
 515         va_start(ap, fmt);
 516         ret = p9pdu_vwritef(pdu, optional, fmt, ap);
 517         va_end(ap);
 518
 519         return ret;
 520 }
 521
 522 int p9stat_read(char *buf, int len, struct p9_wstat *st, int dotu)
 523 {
 524         struct p9_fcall fake_pdu;
 525         int ret;
 526
 527         fake_pdu.size = len;
 528         fake_pdu.capacity = len;
 529         fake_pdu.sdata = buf;
 530         fake_pdu.offset = 0;
 531
 532         ret = p9pdu_readf(&fake_pdu, dotu, "S", st);
 533         if (ret) {
 534                 P9_DPRINTK(P9_DEBUG_9P, "<<< p9stat_read failed: %d\n", ret);
 535                 p9pdu_dump(1, &fake_pdu);
 536         }
 537
 538         return ret;
 539 }
 540 EXPORT_SYMBOL(p9stat_read);
 541
 542 int p9pdu_prepare(struct p9_fcall *pdu, int16_t tag, int8_t type)
 543 {
 544         return p9pdu_writef(pdu, 0, "dbw", 0, type, tag);
 545 }
 546
 547 int p9pdu_finalize(struct p9_fcall *pdu)
 548 {
 549         int size = pdu->size;
 550         int err;
 551
 552         pdu->size = 0;
 553         err = p9pdu_writef(pdu, 0, "d", size);
 554         pdu->size = size;
 555
 556 #ifdef CONFIG_NET_9P_DEBUG
 557         if ((p9_debug_level & P9_DEBUG_PKT) == P9_DEBUG_PKT)
 558                 p9pdu_dump(0, pdu);
 559 #endif
 560
 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 }