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/uaccess.h>
  31 #include <linux/sched.h>
  32 #include <net/9p/9p.h>
  33 #include <net/9p/client.h>
  34 #include "protocol.h"
  35
  36 #ifndef MIN
  37 #define MIN(a, b) (((a) < (b)) ? (a) : (b))
  38 #endif
  39
  40 #ifndef MAX
  41 #define MAX(a, b) (((a) > (b)) ? (a) : (b))
  42 #endif
  43
  44 #ifndef offset_of
  45 #define offset_of(type, memb) \
  46         ((unsigned long)(&((type *)0)->memb))
  47 #endif
  48 #ifndef container_of
  49 #define container_of(obj, type, memb) \
  50         ((type *)(((char *)obj) - offset_of(type, memb)))
  51 #endif
  52
  53 static int
  54 p9pdu_writef(struct p9_fcall *pdu, int optional, const char *fmt, ...);
  55
  56 void
  57 p9pdu_dump(int way, struct p9_fcall *pdu)
  58 {
  59         int i, n;
  60         u8 *data = pdu->sdata;
  61         int datalen = pdu->size;
  62         char buf[255];
  63         int buflen = 255;
  64
  65         i = n = 0;
  66         if (datalen > (buflen-16))
  67                 datalen = buflen-16;
  68         while (i < datalen) {
  69                 n += scnprintf(buf + n, buflen - n, "%02x ", data[i]);
  70                 if (i%4 == 3)
  71                         n += scnprintf(buf + n, buflen - n, " ");
  72                 if (i%32 == 31)
  73                         n += scnprintf(buf + n, buflen - n, "\n");
  74
  75                 i++;
  76         }
  77         n += scnprintf(buf + n, buflen - n, "\n");
  78
  79         if (way)
  80                 P9_DPRINTK(P9_DEBUG_PKT, "[[[(%d) %s\n", datalen, buf);
  81         else
  82                 P9_DPRINTK(P9_DEBUG_PKT, "]]](%d) %s\n", datalen, buf);
  83 }
  84 EXPORT_SYMBOL(p9pdu_dump);
  85
  86 void p9stat_free(struct p9_wstat *stbuf)
  87 {
  88         kfree(stbuf->name);
  89         kfree(stbuf->uid);
  90         kfree(stbuf->gid);
  91         kfree(stbuf->muid);
  92         kfree(stbuf->extension);
  93 }
  94 EXPORT_SYMBOL(p9stat_free);
  95
  96 static size_t pdu_read(struct p9_fcall *pdu, void *data, size_t size)
  97 {
  98         size_t len = MIN(pdu->size - pdu->offset, size);
  99         memcpy(data, &pdu->sdata[pdu->offset], len);
 100         pdu->offset += len;
 101         return size - len;
 102 }
 103
 104 static size_t pdu_write(struct p9_fcall *pdu, const void *data, size_t size)
 105 {
 106         size_t len = MIN(pdu->capacity - pdu->size, size);
 107         memcpy(&pdu->sdata[pdu->size], data, len);
 108         pdu->size += len;
 109         return size - len;
 110 }
 111
 112 static size_t
 113 pdu_write_u(struct p9_fcall *pdu, const char __user *udata, size_t size)
 114 {
 115         size_t len = MIN(pdu->capacity - pdu->size, size);
 116         int err = copy_from_user(&pdu->sdata[pdu->size], udata, len);
 117         if (err)
 118                 printk(KERN_WARNING "pdu_write_u returning: %d\n", err);
 119
 120         pdu->size += len;
 121         return size - len;
 122 }
 123
 124 /*
 125         b - int8_t
 126         w - int16_t
 127         d - int32_t
 128         q - int64_t
 129         s - string
 130         S - stat
 131         Q - qid
 132         D - data blob (int32_t size followed by void *, results are not freed)
 133         T - array of strings (int16_t count, followed by strings)
 134         R - array of qids (int16_t count, followed by qids)
 135         ? - if optional = 1, continue parsing
 136 */
 137
 138 static int
 139 p9pdu_vreadf(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
 140 {
 141         const char *ptr;
 142         int errcode = 0;
 143
 144         for (ptr = fmt; *ptr; ptr++) {
 145                 switch (*ptr) {
 146                 case 'b':{
 147                                 int8_t *val = va_arg(ap, int8_t *);
 148                                 if (pdu_read(pdu, val, sizeof(*val))) {
 149                                         errcode = -EFAULT;
 150                                         break;
 151                                 }
 152                         }
 153                         break;
 154                 case 'w':{
 155                                 int16_t *val = va_arg(ap, int16_t *);
 156                                 if (pdu_read(pdu, val, sizeof(*val))) {
 157                                         errcode = -EFAULT;
 158                                         break;
 159                                 }
 160                                 *val = cpu_to_le16(*val);
 161                         }
 162                         break;
 163                 case 'd':{
 164                                 int32_t *val = va_arg(ap, int32_t *);
 165                                 if (pdu_read(pdu, val, sizeof(*val))) {
 166                                         errcode = -EFAULT;
 167                                         break;
 168                                 }
 169                                 *val = cpu_to_le32(*val);
 170                         }
 171                         break;
 172                 case 'q':{
 173                                 int64_t *val = va_arg(ap, int64_t *);
 174                                 if (pdu_read(pdu, val, sizeof(*val))) {
 175                                         errcode = -EFAULT;
 176                                         break;
 177                                 }
 178                                 *val = cpu_to_le64(*val);
 179                         }
 180                         break;
 181                 case 's':{
 182                                 char **ptr = va_arg(ap, char **);
 183                                 int16_t len;
 184                                 int size;
 185
 186                                 errcode = p9pdu_readf(pdu, optional, "w", &len);
 187                                 if (errcode)
 188                                         break;
 189
 190                                 size = MAX(len, 0);
 191
 192                                 *ptr = kmalloc(size + 1, GFP_KERNEL);
 193                                 if (*ptr == NULL) {
 194                                         errcode = -EFAULT;
 195                                         break;
 196                                 }
 197                                 if (pdu_read(pdu, *ptr, size)) {
 198                                         errcode = -EFAULT;
 199                                         kfree(*ptr);
 200                                         *ptr = NULL;
 201                                 } else
 202                                         (*ptr)[size] = 0;
 203                         }
 204                         break;
 205                 case 'Q':{
 206                                 struct p9_qid *qid =
 207                                     va_arg(ap, struct p9_qid *);
 208
 209                                 errcode = p9pdu_readf(pdu, optional, "bdq",
 210                                                       &qid->type, &qid->version,
 211                                                       &qid->path);
 212                         }
 213                         break;
 214                 case 'S':{
 215                                 struct p9_wstat *stbuf =
 216                                     va_arg(ap, struct p9_wstat *);
 217
 218                                 memset(stbuf, 0, sizeof(struct p9_wstat));
 219                                 stbuf->n_uid = stbuf->n_gid = stbuf->n_muid =
 220                                                                         -1;
 221                                 errcode =
 222                                     p9pdu_readf(pdu, optional,
 223                                                 "wwdQdddqssss?sddd",
 224                                                 &stbuf->size, &stbuf->type,
 225                                                 &stbuf->dev, &stbuf->qid,
 226                                                 &stbuf->mode, &stbuf->atime,
 227                                                 &stbuf->mtime, &stbuf->length,
 228                                                 &stbuf->name, &stbuf->uid,
 229                                                 &stbuf->gid, &stbuf->muid,
 230                                                 &stbuf->extension,
 231                                                 &stbuf->n_uid, &stbuf->n_gid,
 232                                                 &stbuf->n_muid);
 233                                 if (errcode)
 234                                         p9stat_free(stbuf);
 235                         }
 236                         break;
 237                 case 'D':{
 238                                 int32_t *count = va_arg(ap, int32_t *);
 239                                 void **data = va_arg(ap, void **);
 240
 241                                 errcode =
 242                                     p9pdu_readf(pdu, optional, "d", count);
 243                                 if (!errcode) {
 244                                         *count =
 245                                             MIN(*count,
 246                                                 pdu->size - pdu->offset);
 247                                         *data = &pdu->sdata[pdu->offset];
 248                                 }
 249                         }
 250                         break;
 251                 case 'T':{
 252                                 int16_t *nwname = va_arg(ap, int16_t *);
 253                                 char ***wnames = va_arg(ap, char ***);
 254
 255                                 errcode =
 256                                     p9pdu_readf(pdu, optional, "w", nwname);
 257                                 if (!errcode) {
 258                                         *wnames =
 259                                             kmalloc(sizeof(char *) * *nwname,
 260                                                     GFP_KERNEL);
 261                                         if (!*wnames)
 262                                                 errcode = -ENOMEM;
 263                                 }
 264
 265                                 if (!errcode) {
 266                                         int i;
 267
 268                                         for (i = 0; i < *nwname; i++) {
 269                                                 errcode =
 270                                                     p9pdu_readf(pdu, optional,
 271                                                                 "s",
 272                                                                 &(*wnames)[i]);
 273                                                 if (errcode)
 274                                                         break;
 275                                         }
 276                                 }
 277
 278                                 if (errcode) {
 279                                         if (*wnames) {
 280                                                 int i;
 281
 282                                                 for (i = 0; i < *nwname; i++)
 283                                                         kfree((*wnames)[i]);
 284                                         }
 285                                         kfree(*wnames);
 286                                         *wnames = NULL;
 287                                 }
 288                         }
 289                         break;
 290                 case 'R':{
 291                                 int16_t *nwqid = va_arg(ap, int16_t *);
 292                                 struct p9_qid **wqids =
 293                                     va_arg(ap, struct p9_qid **);
 294
 295                                 *wqids = NULL;
 296
 297                                 errcode =
 298                                     p9pdu_readf(pdu, optional, "w", nwqid);
 299                                 if (!errcode) {
 300                                         *wqids =
 301                                             kmalloc(*nwqid *
 302                                                     sizeof(struct p9_qid),
 303                                                     GFP_KERNEL);
 304                                         if (*wqids == NULL)
 305                                                 errcode = -ENOMEM;
 306                                 }
 307
 308                                 if (!errcode) {
 309                                         int i;
 310
 311                                         for (i = 0; i < *nwqid; i++) {
 312                                                 errcode =
 313                                                     p9pdu_readf(pdu, optional,
 314                                                                 "Q",
 315                                                                 &(*wqids)[i]);
 316                                                 if (errcode)
 317                                                         break;
 318                                         }
 319                                 }
 320
 321                                 if (errcode) {
 322                                         kfree(*wqids);
 323                                         *wqids = NULL;
 324                                 }
 325                         }
 326                         break;
 327                 case '?':
 328                         if (!optional)
 329                                 return 0;
 330                         break;
 331                 default:
 332                         BUG();
 333                         break;
 334                 }
 335
 336                 if (errcode)
 337                         break;
 338         }
 339
 340         return errcode;
 341 }
 342
 343 int
 344 p9pdu_vwritef(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
 345 {
 346         const char *ptr;
 347         int errcode = 0;
 348
 349         for (ptr = fmt; *ptr; ptr++) {
 350                 switch (*ptr) {
 351                 case 'b':{
 352                                 int8_t val = va_arg(ap, int);
 353                                 if (pdu_write(pdu, &val, sizeof(val)))
 354                                         errcode = -EFAULT;
 355                         }
 356                         break;
 357                 case 'w':{
 358                                 int16_t val = va_arg(ap, int);
 359                                 if (pdu_write(pdu, &val, sizeof(val)))
 360                                         errcode = -EFAULT;
 361                         }
 362                         break;
 363                 case 'd':{
 364                                 int32_t val = va_arg(ap, int32_t);
 365                                 if (pdu_write(pdu, &val, sizeof(val)))
 366                                         errcode = -EFAULT;
 367                         }
 368                         break;
 369                 case 'q':{
 370                                 int64_t val = va_arg(ap, int64_t);
 371                                 if (pdu_write(pdu, &val, sizeof(val)))
 372                                         errcode = -EFAULT;
 373                         }
 374                         break;
 375                 case 's':{
 376                                 const char *ptr = va_arg(ap, const char *);
 377                                 int16_t len = 0;
 378                                 if (ptr)
 379                                         len = MIN(strlen(ptr), USHORT_MAX);
 380
 381                                 errcode = p9pdu_writef(pdu, optional, "w", len);
 382                                 if (!errcode && pdu_write(pdu, ptr, len))
 383                                         errcode = -EFAULT;
 384                         }
 385                         break;
 386                 case 'Q':{
 387                                 const struct p9_qid *qid =
 388                                     va_arg(ap, const struct p9_qid *);
 389                                 errcode =
 390                                     p9pdu_writef(pdu, optional, "bdq",
 391                                                  qid->type, qid->version,
 392                                                  qid->path);
 393                         } break;
 394                 case 'S':{
 395                                 const struct p9_wstat *stbuf =
 396                                     va_arg(ap, const struct p9_wstat *);
 397                                 errcode =
 398                                     p9pdu_writef(pdu, optional,
 399                                                  "wwdQdddqssss?sddd",
 400                                                  stbuf->size, stbuf->type,
 401                                                  stbuf->dev, &stbuf->qid,
 402                                                  stbuf->mode, stbuf->atime,
 403                                                  stbuf->mtime, stbuf->length,
 404                                                  stbuf->name, stbuf->uid,
 405                                                  stbuf->gid, stbuf->muid,
 406                                                  stbuf->extension, stbuf->n_uid,
 407                                                  stbuf->n_gid, stbuf->n_muid);
 408                         } break;
 409                 case 'D':{
 410                                 int32_t count = va_arg(ap, int32_t);
 411                                 const void *data = va_arg(ap, const void *);
 412
 413                                 errcode =
 414                                     p9pdu_writef(pdu, optional, "d", count);
 415                                 if (!errcode && pdu_write(pdu, data, count))
 416                                         errcode = -EFAULT;
 417                         }
 418                         break;
 419                 case 'U':{
 420                                 int32_t count = va_arg(ap, int32_t);
 421                                 const char __user *udata =
 422                                                 va_arg(ap, const void *);
 423                                 errcode =
 424                                     p9pdu_writef(pdu, optional, "d", count);
 425                                 if (!errcode && pdu_write_u(pdu, udata, count))
 426                                         errcode = -EFAULT;
 427                         }
 428                         break;
 429                 case 'T':{
 430                                 int16_t nwname = va_arg(ap, int);
 431                                 const char **wnames = va_arg(ap, const char **);
 432
 433                                 errcode =
 434                                     p9pdu_writef(pdu, optional, "w", nwname);
 435                                 if (!errcode) {
 436                                         int i;
 437
 438                                         for (i = 0; i < nwname; i++) {
 439                                                 errcode =
 440                                                     p9pdu_writef(pdu, optional,
 441                                                                  "s",
 442                                                                  wnames[i]);
 443                                                 if (errcode)
 444                                                         break;
 445                                         }
 446                                 }
 447                         }
 448                         break;
 449                 case 'R':{
 450                                 int16_t nwqid = va_arg(ap, int);
 451                                 struct p9_qid *wqids =
 452                                     va_arg(ap, struct p9_qid *);
 453
 454                                 errcode =
 455                                     p9pdu_writef(pdu, optional, "w", nwqid);
 456                                 if (!errcode) {
 457                                         int i;
 458
 459                                         for (i = 0; i < nwqid; i++) {
 460                                                 errcode =
 461                                                     p9pdu_writef(pdu, optional,
 462                                                                  "Q",
 463                                                                  &wqids[i]);
 464                                                 if (errcode)
 465                                                         break;
 466                                         }
 467                                 }
 468                         }
 469                         break;
 470                 case '?':
 471                         if (!optional)
 472                                 return 0;
 473                         break;
 474                 default:
 475                         BUG();
 476                         break;
 477                 }
 478
 479                 if (errcode)
 480                         break;
 481         }
 482
 483         return errcode;
 484 }
 485
 486 int p9pdu_readf(struct p9_fcall *pdu, int optional, const char *fmt, ...)
 487 {
 488         va_list ap;
 489         int ret;
 490
 491         va_start(ap, fmt);
 492         ret = p9pdu_vreadf(pdu, optional, fmt, ap);
 493         va_end(ap);
 494
 495         return ret;
 496 }
 497
 498 static int
 499 p9pdu_writef(struct p9_fcall *pdu, int optional, const char *fmt, ...)
 500 {
 501         va_list ap;
 502         int ret;
 503
 504         va_start(ap, fmt);
 505         ret = p9pdu_vwritef(pdu, optional, fmt, ap);
 506         va_end(ap);
 507
 508         return ret;
 509 }
 510
 511 int p9stat_read(char *buf, int len, struct p9_wstat *st, int dotu)
 512 {
 513         struct p9_fcall fake_pdu;
 514         int ret;
 515
 516         fake_pdu.size = len;
 517         fake_pdu.capacity = len;
 518         fake_pdu.sdata = buf;
 519         fake_pdu.offset = 0;
 520
 521         ret = p9pdu_readf(&fake_pdu, dotu, "S", st);
 522         if (ret) {
 523                 P9_DPRINTK(P9_DEBUG_9P, "<<< p9stat_read failed: %d\n", ret);
 524                 p9pdu_dump(1, &fake_pdu);
 525         }
 526
 527         return ret;
 528 }
 529 EXPORT_SYMBOL(p9stat_read);
 530
 531 int p9pdu_prepare(struct p9_fcall *pdu, int16_t tag, int8_t type)
 532 {
 533         return p9pdu_writef(pdu, 0, "dbw", 0, type, tag);
 534 }
 535
 536 int p9pdu_finalize(struct p9_fcall *pdu)
 537 {
 538         int size = pdu->size;
 539         int err;
 540
 541         pdu->size = 0;
 542         err = p9pdu_writef(pdu, 0, "d", size);
 543         pdu->size = size;
 544
 545         if ((p9_debug_level & P9_DEBUG_PKT) == P9_DEBUG_PKT)
 546                 p9pdu_dump(0, pdu);
 547
 548         P9_DPRINTK(P9_DEBUG_9P, ">>> size=%d type: %d tag: %d\n", pdu->size,
 549                                                         pdu->id, pdu->tag);
 550
 551         return err;
 552 }
 553
 554 void p9pdu_reset(struct p9_fcall *pdu)
 555 {
 556         pdu->offset = 0;
 557         pdu->size = 0;
 558 }