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