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