hw/virtio-9p.c

   1 /*
   2  * Virtio 9p backend
   3  *
   4  * Copyright IBM, Corp. 2010
   5  *
   6  * Authors:
   7  *  Anthony Liguori   <aliguori@us.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  *
  12  */
  13
  14 #include "virtio.h"
  15 #include "pc.h"
  16 #include "qemu_socket.h"
  17 #include "virtio-9p.h"
  18 #include "fsdev/qemu-fsdev.h"
  19 #include "virtio-9p-debug.h"
  20
  21 int dotu = 1;
  22 int debug_9p_pdu;
  23
  24 static int v9fs_do_lstat(V9fsState *s, V9fsString *path, struct stat *stbuf)
  25 {
  26     return s->ops->lstat(&s->ctx, path->data, stbuf);
  27 }
  28
  29 static int v9fs_do_setuid(V9fsState *s, uid_t uid)
  30 {
  31     return s->ops->setuid(&s->ctx, uid);
  32 }
  33
  34 static ssize_t v9fs_do_readlink(V9fsState *s, V9fsString *path, V9fsString *buf)
  35 {
  36     ssize_t len;
  37
  38     buf->data = qemu_malloc(1024);
  39
  40     len = s->ops->readlink(&s->ctx, path->data, buf->data, 1024 - 1);
  41     if (len > -1) {
  42         buf->size = len;
  43         buf->data[len] = 0;
  44     }
  45
  46     return len;
  47 }
  48
  49 static int v9fs_do_close(V9fsState *s, int fd)
  50 {
  51     return s->ops->close(&s->ctx, fd);
  52 }
  53
  54 static int v9fs_do_closedir(V9fsState *s, DIR *dir)
  55 {
  56     return s->ops->closedir(&s->ctx, dir);
  57 }
  58
  59 static void v9fs_string_init(V9fsString *str)
  60 {
  61     str->data = NULL;
  62     str->size = 0;
  63 }
  64
  65 static void v9fs_string_free(V9fsString *str)
  66 {
  67     qemu_free(str->data);
  68     str->data = NULL;
  69     str->size = 0;
  70 }
  71
  72 static void v9fs_string_null(V9fsString *str)
  73 {
  74     v9fs_string_free(str);
  75 }
  76
  77 static int number_to_string(void *arg, char type)
  78 {
  79     unsigned int ret = 0;
  80
  81     switch (type) {
  82     case 'u': {
  83         unsigned int num = *(unsigned int *)arg;
  84
  85         do {
  86             ret++;
  87             num = num/10;
  88         } while (num);
  89         break;
  90     }
  91     default:
  92         printf("Number_to_string: Unknown number format\n");
  93         return -1;
  94     }
  95
  96     return ret;
  97 }
  98
  99 static int v9fs_string_alloc_printf(char **strp, const char *fmt, va_list ap)
 100 {
 101     va_list ap2;
 102     char *iter = (char *)fmt;
 103     int len = 0;
 104     int nr_args = 0;
 105     char *arg_char_ptr;
 106     unsigned int arg_uint;
 107
 108     /* Find the number of %'s that denotes an argument */
 109     for (iter = strstr(iter, "%"); iter; iter = strstr(iter, "%")) {
 110         nr_args++;
 111         iter++;
 112     }
 113
 114     len = strlen(fmt) - 2*nr_args;
 115
 116     if (!nr_args) {
 117         goto alloc_print;
 118     }
 119
 120     va_copy(ap2, ap);
 121
 122     iter = (char *)fmt;
 123
 124     /* Now parse the format string */
 125     for (iter = strstr(iter, "%"); iter; iter = strstr(iter, "%")) {
 126         iter++;
 127         switch (*iter) {
 128         case 'u':
 129             arg_uint = va_arg(ap2, unsigned int);
 130             len += number_to_string((void *)&arg_uint, 'u');
 131             break;
 132         case 's':
 133             arg_char_ptr = va_arg(ap2, char *);
 134             len += strlen(arg_char_ptr);
 135             break;
 136         case 'c':
 137             len += 1;
 138             break;
 139         default:
 140             fprintf(stderr,
 141                     "v9fs_string_alloc_printf:Incorrect format %c", *iter);
 142             return -1;
 143         }
 144         iter++;
 145     }
 146
 147 alloc_print:
 148     *strp = qemu_malloc((len + 1) * sizeof(**strp));
 149
 150     return vsprintf(*strp, fmt, ap);
 151 }
 152
 153 static void v9fs_string_sprintf(V9fsString *str, const char *fmt, ...)
 154 {
 155     va_list ap;
 156     int err;
 157
 158     v9fs_string_free(str);
 159
 160     va_start(ap, fmt);
 161     err = v9fs_string_alloc_printf(&str->data, fmt, ap);
 162     BUG_ON(err == -1);
 163     va_end(ap);
 164
 165     str->size = err;
 166 }
 167
 168 static void v9fs_string_copy(V9fsString *lhs, V9fsString *rhs)
 169 {
 170     v9fs_string_free(lhs);
 171     v9fs_string_sprintf(lhs, "%s", rhs->data);
 172 }
 173
 174 static size_t v9fs_string_size(V9fsString *str)
 175 {
 176     return str->size;
 177 }
 178
 179 static V9fsPDU *alloc_pdu(V9fsState *s)
 180 {
 181     V9fsPDU *pdu = NULL;
 182
 183     if (!QLIST_EMPTY(&s->free_list)) {
 184         pdu = QLIST_FIRST(&s->free_list);
 185         QLIST_REMOVE(pdu, next);
 186     }
 187     return pdu;
 188 }
 189
 190 static void free_pdu(V9fsState *s, V9fsPDU *pdu)
 191 {
 192     if (pdu) {
 193         QLIST_INSERT_HEAD(&s->free_list, pdu, next);
 194     }
 195 }
 196
 197 size_t pdu_packunpack(void *addr, struct iovec *sg, int sg_count,
 198                         size_t offset, size_t size, int pack)
 199 {
 200     int i = 0;
 201     size_t copied = 0;
 202
 203     for (i = 0; size && i < sg_count; i++) {
 204         size_t len;
 205         if (offset >= sg[i].iov_len) {
 206             /* skip this sg */
 207             offset -= sg[i].iov_len;
 208             continue;
 209         } else {
 210             len = MIN(sg[i].iov_len - offset, size);
 211             if (pack) {
 212                 memcpy(sg[i].iov_base + offset, addr, len);
 213             } else {
 214                 memcpy(addr, sg[i].iov_base + offset, len);
 215             }
 216             size -= len;
 217             copied += len;
 218             addr += len;
 219             if (size) {
 220                 offset = 0;
 221                 continue;
 222             }
 223         }
 224     }
 225
 226     return copied;
 227 }
 228
 229 static size_t pdu_unpack(void *dst, V9fsPDU *pdu, size_t offset, size_t size)
 230 {
 231     return pdu_packunpack(dst, pdu->elem.out_sg, pdu->elem.out_num,
 232                          offset, size, 0);
 233 }
 234
 235 static size_t pdu_pack(V9fsPDU *pdu, size_t offset, const void *src,
 236                         size_t size)
 237 {
 238     return pdu_packunpack((void *)src, pdu->elem.in_sg, pdu->elem.in_num,
 239                              offset, size, 1);
 240 }
 241
 242 static int pdu_copy_sg(V9fsPDU *pdu, size_t offset, int rx, struct iovec *sg)
 243 {
 244     size_t pos = 0;
 245     int i, j;
 246     struct iovec *src_sg;
 247     unsigned int num;
 248
 249     if (rx) {
 250         src_sg = pdu->elem.in_sg;
 251         num = pdu->elem.in_num;
 252     } else {
 253         src_sg = pdu->elem.out_sg;
 254         num = pdu->elem.out_num;
 255     }
 256
 257     j = 0;
 258     for (i = 0; i < num; i++) {
 259         if (offset <= pos) {
 260             sg[j].iov_base = src_sg[i].iov_base;
 261             sg[j].iov_len = src_sg[i].iov_len;
 262             j++;
 263         } else if (offset < (src_sg[i].iov_len + pos)) {
 264             sg[j].iov_base = src_sg[i].iov_base;
 265             sg[j].iov_len = src_sg[i].iov_len;
 266             sg[j].iov_base += (offset - pos);
 267             sg[j].iov_len -= (offset - pos);
 268             j++;
 269         }
 270         pos += src_sg[i].iov_len;
 271     }
 272
 273     return j;
 274 }
 275
 276 static size_t pdu_unmarshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...)
 277 {
 278     size_t old_offset = offset;
 279     va_list ap;
 280     int i;
 281
 282     va_start(ap, fmt);
 283     for (i = 0; fmt[i]; i++) {
 284         switch (fmt[i]) {
 285         case 'b': {
 286             uint8_t *valp = va_arg(ap, uint8_t *);
 287             offset += pdu_unpack(valp, pdu, offset, sizeof(*valp));
 288             break;
 289         }
 290         case 'w': {
 291             uint16_t val, *valp;
 292             valp = va_arg(ap, uint16_t *);
 293             val = le16_to_cpupu(valp);
 294             offset += pdu_unpack(&val, pdu, offset, sizeof(val));
 295             *valp = val;
 296             break;
 297         }
 298         case 'd': {
 299             uint32_t val, *valp;
 300             valp = va_arg(ap, uint32_t *);
 301             val = le32_to_cpupu(valp);
 302             offset += pdu_unpack(&val, pdu, offset, sizeof(val));
 303             *valp = val;
 304             break;
 305         }
 306         case 'q': {
 307             uint64_t val, *valp;
 308             valp = va_arg(ap, uint64_t *);
 309             val = le64_to_cpup(valp);
 310             offset += pdu_unpack(&val, pdu, offset, sizeof(val));
 311             *valp = val;
 312             break;
 313         }
 314         case 'v': {
 315             struct iovec *iov = va_arg(ap, struct iovec *);
 316             int *iovcnt = va_arg(ap, int *);
 317             *iovcnt = pdu_copy_sg(pdu, offset, 0, iov);
 318             break;
 319         }
 320         case 's': {
 321             V9fsString *str = va_arg(ap, V9fsString *);
 322             offset += pdu_unmarshal(pdu, offset, "w", &str->size);
 323             /* FIXME: sanity check str->size */
 324             str->data = qemu_malloc(str->size + 1);
 325             offset += pdu_unpack(str->data, pdu, offset, str->size);
 326             str->data[str->size] = 0;
 327             break;
 328         }
 329         case 'Q': {
 330             V9fsQID *qidp = va_arg(ap, V9fsQID *);
 331             offset += pdu_unmarshal(pdu, offset, "bdq",
 332                         &qidp->type, &qidp->version, &qidp->path);
 333             break;
 334         }
 335         case 'S': {
 336             V9fsStat *statp = va_arg(ap, V9fsStat *);
 337             offset += pdu_unmarshal(pdu, offset, "wwdQdddqsssssddd",
 338                         &statp->size, &statp->type, &statp->dev,
 339                         &statp->qid, &statp->mode, &statp->atime,
 340                         &statp->mtime, &statp->length,
 341                         &statp->name, &statp->uid, &statp->gid,
 342                         &statp->muid, &statp->extension,
 343                         &statp->n_uid, &statp->n_gid,
 344                         &statp->n_muid);
 345             break;
 346         }
 347         default:
 348             break;
 349         }
 350     }
 351
 352     va_end(ap);
 353
 354     return offset - old_offset;
 355 }
 356
 357 static size_t pdu_marshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...)
 358 {
 359     size_t old_offset = offset;
 360     va_list ap;
 361     int i;
 362
 363     va_start(ap, fmt);
 364     for (i = 0; fmt[i]; i++) {
 365         switch (fmt[i]) {
 366         case 'b': {
 367             uint8_t val = va_arg(ap, int);
 368             offset += pdu_pack(pdu, offset, &val, sizeof(val));
 369             break;
 370         }
 371         case 'w': {
 372             uint16_t val;
 373             cpu_to_le16w(&val, va_arg(ap, int));
 374             offset += pdu_pack(pdu, offset, &val, sizeof(val));
 375             break;
 376         }
 377         case 'd': {
 378             uint32_t val;
 379             cpu_to_le32w(&val, va_arg(ap, uint32_t));
 380             offset += pdu_pack(pdu, offset, &val, sizeof(val));
 381             break;
 382         }
 383         case 'q': {
 384             uint64_t val;
 385             cpu_to_le64w(&val, va_arg(ap, uint64_t));
 386             offset += pdu_pack(pdu, offset, &val, sizeof(val));
 387             break;
 388         }
 389         case 'v': {
 390             struct iovec *iov = va_arg(ap, struct iovec *);
 391             int *iovcnt = va_arg(ap, int *);
 392             *iovcnt = pdu_copy_sg(pdu, offset, 1, iov);
 393             break;
 394         }
 395         case 's': {
 396             V9fsString *str = va_arg(ap, V9fsString *);
 397             offset += pdu_marshal(pdu, offset, "w", str->size);
 398             offset += pdu_pack(pdu, offset, str->data, str->size);
 399             break;
 400         }
 401         case 'Q': {
 402             V9fsQID *qidp = va_arg(ap, V9fsQID *);
 403             offset += pdu_marshal(pdu, offset, "bdq",
 404                         qidp->type, qidp->version, qidp->path);
 405             break;
 406         }
 407         case 'S': {
 408             V9fsStat *statp = va_arg(ap, V9fsStat *);
 409             offset += pdu_marshal(pdu, offset, "wwdQdddqsssssddd",
 410                         statp->size, statp->type, statp->dev,
 411                         &statp->qid, statp->mode, statp->atime,
 412                         statp->mtime, statp->length, &statp->name,
 413                         &statp->uid, &statp->gid, &statp->muid,
 414                         &statp->extension, statp->n_uid,
 415                         statp->n_gid, statp->n_muid);
 416             break;
 417         }
 418         default:
 419             break;
 420         }
 421     }
 422     va_end(ap);
 423
 424     return offset - old_offset;
 425 }
 426
 427 static void complete_pdu(V9fsState *s, V9fsPDU *pdu, ssize_t len)
 428 {
 429     int8_t id = pdu->id + 1; /* Response */
 430
 431     if (len < 0) {
 432         V9fsString str;
 433         int err = -len;
 434
 435         str.data = strerror(err);
 436         str.size = strlen(str.data);
 437
 438         len = 7;
 439         len += pdu_marshal(pdu, len, "s", &str);
 440         if (dotu) {
 441             len += pdu_marshal(pdu, len, "d", err);
 442         }
 443
 444         id = P9_RERROR;
 445     }
 446
 447     /* fill out the header */
 448     pdu_marshal(pdu, 0, "dbw", (int32_t)len, id, pdu->tag);
 449
 450     /* keep these in sync */
 451     pdu->size = len;
 452     pdu->id = id;
 453
 454     /* push onto queue and notify */
 455     virtqueue_push(s->vq, &pdu->elem, len);
 456
 457     /* FIXME: we should batch these completions */
 458     virtio_notify(&s->vdev, s->vq);
 459
 460     free_pdu(s, pdu);
 461 }
 462
 463 static void v9fs_dummy(V9fsState *s, V9fsPDU *pdu)
 464 {
 465     /* Note: The following have been added to prevent GCC from complaining
 466      * They will be removed in the subsequent patches */
 467     (void)pdu_unmarshal;
 468     (void) complete_pdu;
 469     (void) v9fs_string_init;
 470     (void) v9fs_string_free;
 471     (void) v9fs_string_null;
 472     (void) v9fs_string_sprintf;
 473     (void) v9fs_string_copy;
 474     (void) v9fs_string_size;
 475     (void) v9fs_do_lstat;
 476     (void) v9fs_do_setuid;
 477     (void) v9fs_do_readlink;
 478     (void) v9fs_do_close;
 479     (void) v9fs_do_closedir;
 480 }
 481
 482 static void v9fs_version(V9fsState *s, V9fsPDU *pdu)
 483 {
 484     if (debug_9p_pdu) {
 485         pprint_pdu(pdu);
 486     }
 487 }
 488
 489 static void v9fs_attach(V9fsState *s, V9fsPDU *pdu)
 490 {
 491     if (debug_9p_pdu) {
 492         pprint_pdu(pdu);
 493     }
 494 }
 495
 496 static void v9fs_stat(V9fsState *s, V9fsPDU *pdu)
 497 {
 498     if (debug_9p_pdu) {
 499         pprint_pdu(pdu);
 500     }
 501 }
 502
 503 static void v9fs_walk(V9fsState *s, V9fsPDU *pdu)
 504 {
 505     if (debug_9p_pdu) {
 506         pprint_pdu(pdu);
 507     }
 508 }
 509
 510 static void v9fs_clunk(V9fsState *s, V9fsPDU *pdu)
 511 {
 512     if (debug_9p_pdu) {
 513         pprint_pdu(pdu);
 514     }
 515 }
 516
 517 static void v9fs_open(V9fsState *s, V9fsPDU *pdu)
 518 {    if (debug_9p_pdu) {
 519         pprint_pdu(pdu);
 520      }
 521 }
 522
 523 static void v9fs_read(V9fsState *s, V9fsPDU *pdu)
 524 {
 525     if (debug_9p_pdu) {
 526         pprint_pdu(pdu);
 527     }
 528 }
 529
 530 static void v9fs_write(V9fsState *s, V9fsPDU *pdu)
 531 {
 532     if (debug_9p_pdu) {
 533         pprint_pdu(pdu);
 534     }
 535 }
 536
 537 static void v9fs_create(V9fsState *s, V9fsPDU *pdu)
 538 {
 539     if (debug_9p_pdu) {
 540         pprint_pdu(pdu);
 541     }
 542 }
 543
 544 static void v9fs_flush(V9fsState *s, V9fsPDU *pdu)
 545 {
 546     v9fs_dummy(s, pdu);
 547     if (debug_9p_pdu) {
 548         pprint_pdu(pdu);
 549     }
 550 }
 551
 552 static void v9fs_remove(V9fsState *s, V9fsPDU *pdu)
 553 {
 554     if (debug_9p_pdu) {
 555         pprint_pdu(pdu);
 556     }
 557 }
 558
 559 static void v9fs_wstat(V9fsState *s, V9fsPDU *pdu)
 560 {
 561     if (debug_9p_pdu) {
 562         pprint_pdu(pdu);
 563     }
 564 }
 565
 566 typedef void (pdu_handler_t)(V9fsState *s, V9fsPDU *pdu);
 567
 568 static pdu_handler_t *pdu_handlers[] = {
 569     [P9_TVERSION] = v9fs_version,
 570     [P9_TATTACH] = v9fs_attach,
 571     [P9_TSTAT] = v9fs_stat,
 572     [P9_TWALK] = v9fs_walk,
 573     [P9_TCLUNK] = v9fs_clunk,
 574     [P9_TOPEN] = v9fs_open,
 575     [P9_TREAD] = v9fs_read,
 576 #if 0
 577     [P9_TAUTH] = v9fs_auth,
 578 #endif
 579     [P9_TFLUSH] = v9fs_flush,
 580     [P9_TCREATE] = v9fs_create,
 581     [P9_TWRITE] = v9fs_write,
 582     [P9_TWSTAT] = v9fs_wstat,
 583     [P9_TREMOVE] = v9fs_remove,
 584 };
 585
 586 static void submit_pdu(V9fsState *s, V9fsPDU *pdu)
 587 {
 588     pdu_handler_t *handler;
 589
 590     if (debug_9p_pdu) {
 591         pprint_pdu(pdu);
 592     }
 593
 594     BUG_ON(pdu->id >= ARRAY_SIZE(pdu_handlers));
 595
 596     handler = pdu_handlers[pdu->id];
 597     BUG_ON(handler == NULL);
 598
 599     handler(s, pdu);
 600 }
 601
 602 static void handle_9p_output(VirtIODevice *vdev, VirtQueue *vq)
 603 {
 604     V9fsState *s = (V9fsState *)vdev;
 605     V9fsPDU *pdu;
 606     ssize_t len;
 607
 608     while ((pdu = alloc_pdu(s)) &&
 609             (len = virtqueue_pop(vq, &pdu->elem)) != 0) {
 610         uint8_t *ptr;
 611
 612         BUG_ON(pdu->elem.out_num == 0 || pdu->elem.in_num == 0);
 613         BUG_ON(pdu->elem.out_sg[0].iov_len < 7);
 614
 615         ptr = pdu->elem.out_sg[0].iov_base;
 616
 617         memcpy(&pdu->size, ptr, 4);
 618         pdu->id = ptr[4];
 619         memcpy(&pdu->tag, ptr + 5, 2);
 620
 621         submit_pdu(s, pdu);
 622     }
 623
 624     free_pdu(s, pdu);
 625 }
 626
 627 static uint32_t virtio_9p_get_features(VirtIODevice *vdev, uint32_t features)
 628 {
 629     features |= 1 << VIRTIO_9P_MOUNT_TAG;
 630     return features;
 631 }
 632
 633 static V9fsState *to_virtio_9p(VirtIODevice *vdev)
 634 {
 635     return (V9fsState *)vdev;
 636 }
 637
 638 static void virtio_9p_get_config(VirtIODevice *vdev, uint8_t *config)
 639 {
 640     struct virtio_9p_config *cfg;
 641     V9fsState *s = to_virtio_9p(vdev);
 642
 643     cfg = qemu_mallocz(sizeof(struct virtio_9p_config) +
 644                         s->tag_len);
 645     stw_raw(&cfg->tag_len, s->tag_len);
 646     memcpy(cfg->tag, s->tag, s->tag_len);
 647     memcpy(config, cfg, s->config_size);
 648     qemu_free(cfg);
 649 }
 650
 651 VirtIODevice *virtio_9p_init(DeviceState *dev, V9fsConf *conf)
 652  {
 653     V9fsState *s;
 654     int i, len;
 655     struct stat stat;
 656     FsTypeEntry *fse;
 657
 658
 659     s = (V9fsState *)virtio_common_init("virtio-9p",
 660                                     VIRTIO_ID_9P,
 661                                     sizeof(struct virtio_9p_config)+
 662                                     MAX_TAG_LEN,
 663                                     sizeof(V9fsState));
 664
 665     /* initialize pdu allocator */
 666     QLIST_INIT(&s->free_list);
 667     for (i = 0; i < (MAX_REQ - 1); i++) {
 668         QLIST_INSERT_HEAD(&s->free_list, &s->pdus[i], next);
 669     }
 670
 671     s->vq = virtio_add_queue(&s->vdev, MAX_REQ, handle_9p_output);
 672
 673     fse = get_fsdev_fsentry(conf->fsdev_id);
 674
 675     if (!fse) {
 676         /* We don't have a fsdev identified by fsdev_id */
 677         fprintf(stderr, "Virtio-9p device couldn't find fsdev "
 678                     "with the id %s\n", conf->fsdev_id);
 679         exit(1);
 680     }
 681
 682     if (!fse->path || !conf->tag) {
 683         /* we haven't specified a mount_tag or the path */
 684         fprintf(stderr, "fsdev with id %s needs path "
 685                 "and Virtio-9p device needs mount_tag arguments\n",
 686                 conf->fsdev_id);
 687         exit(1);
 688     }
 689
 690     if (lstat(fse->path, &stat)) {
 691         fprintf(stderr, "share path %s does not exist\n", fse->path);
 692         exit(1);
 693     } else if (!S_ISDIR(stat.st_mode)) {
 694         fprintf(stderr, "share path %s is not a directory \n", fse->path);
 695         exit(1);
 696     }
 697
 698     s->ctx.fs_root = qemu_strdup(fse->path);
 699     len = strlen(conf->tag);
 700     if (len > MAX_TAG_LEN) {
 701         len = MAX_TAG_LEN;
 702     }
 703     /* s->tag is non-NULL terminated string */
 704     s->tag = qemu_malloc(len);
 705     memcpy(s->tag, conf->tag, len);
 706     s->tag_len = len;
 707     s->ctx.uid = -1;
 708
 709     s->ops = fse->ops;
 710     s->vdev.get_features = virtio_9p_get_features;
 711     s->config_size = sizeof(struct virtio_9p_config) +
 712                         s->tag_len;
 713     s->vdev.get_config = virtio_9p_get_config;
 714
 715     return &s->vdev;
 716 }