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 V9fsPDU *alloc_pdu(V9fsState *s)
  25 {
  26     V9fsPDU *pdu = NULL;
  27
  28     if (!QLIST_EMPTY(&s->free_list)) {
  29         pdu = QLIST_FIRST(&s->free_list);
  30         QLIST_REMOVE(pdu, next);
  31     }
  32     return pdu;
  33 }
  34
  35 static void free_pdu(V9fsState *s, V9fsPDU *pdu)
  36 {
  37     if (pdu) {
  38         QLIST_INSERT_HEAD(&s->free_list, pdu, next);
  39     }
  40 }
  41
  42 size_t pdu_packunpack(void *addr, struct iovec *sg, int sg_count,
  43                         size_t offset, size_t size, int pack)
  44 {
  45     int i = 0;
  46     size_t copied = 0;
  47
  48     for (i = 0; size && i < sg_count; i++) {
  49         size_t len;
  50         if (offset >= sg[i].iov_len) {
  51             /* skip this sg */
  52             offset -= sg[i].iov_len;
  53             continue;
  54         } else {
  55             len = MIN(sg[i].iov_len - offset, size);
  56             if (pack) {
  57                 memcpy(sg[i].iov_base + offset, addr, len);
  58             } else {
  59                 memcpy(addr, sg[i].iov_base + offset, len);
  60             }
  61             size -= len;
  62             copied += len;
  63             addr += len;
  64             if (size) {
  65                 offset = 0;
  66                 continue;
  67             }
  68         }
  69     }
  70
  71     return copied;
  72 }
  73
  74 static size_t pdu_unpack(void *dst, V9fsPDU *pdu, size_t offset, size_t size)
  75 {
  76     return pdu_packunpack(dst, pdu->elem.out_sg, pdu->elem.out_num,
  77                          offset, size, 0);
  78 }
  79
  80 static size_t pdu_pack(V9fsPDU *pdu, size_t offset, const void *src,
  81                         size_t size)
  82 {
  83     return pdu_packunpack((void *)src, pdu->elem.in_sg, pdu->elem.in_num,
  84                              offset, size, 1);
  85 }
  86
  87 static int pdu_copy_sg(V9fsPDU *pdu, size_t offset, int rx, struct iovec *sg)
  88 {
  89     size_t pos = 0;
  90     int i, j;
  91     struct iovec *src_sg;
  92     unsigned int num;
  93
  94     if (rx) {
  95         src_sg = pdu->elem.in_sg;
  96         num = pdu->elem.in_num;
  97     } else {
  98         src_sg = pdu->elem.out_sg;
  99         num = pdu->elem.out_num;
 100     }
 101
 102     j = 0;
 103     for (i = 0; i < num; i++) {
 104         if (offset <= pos) {
 105             sg[j].iov_base = src_sg[i].iov_base;
 106             sg[j].iov_len = src_sg[i].iov_len;
 107             j++;
 108         } else if (offset < (src_sg[i].iov_len + pos)) {
 109             sg[j].iov_base = src_sg[i].iov_base;
 110             sg[j].iov_len = src_sg[i].iov_len;
 111             sg[j].iov_base += (offset - pos);
 112             sg[j].iov_len -= (offset - pos);
 113             j++;
 114         }
 115         pos += src_sg[i].iov_len;
 116     }
 117
 118     return j;
 119 }
 120
 121 static size_t pdu_unmarshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...)
 122 {
 123     size_t old_offset = offset;
 124     va_list ap;
 125     int i;
 126
 127     va_start(ap, fmt);
 128     for (i = 0; fmt[i]; i++) {
 129         switch (fmt[i]) {
 130         case 'b': {
 131             uint8_t *valp = va_arg(ap, uint8_t *);
 132             offset += pdu_unpack(valp, pdu, offset, sizeof(*valp));
 133             break;
 134         }
 135         case 'w': {
 136             uint16_t val, *valp;
 137             valp = va_arg(ap, uint16_t *);
 138             val = le16_to_cpupu(valp);
 139             offset += pdu_unpack(&val, pdu, offset, sizeof(val));
 140             *valp = val;
 141             break;
 142         }
 143         case 'd': {
 144             uint32_t val, *valp;
 145             valp = va_arg(ap, uint32_t *);
 146             val = le32_to_cpupu(valp);
 147             offset += pdu_unpack(&val, pdu, offset, sizeof(val));
 148             *valp = val;
 149             break;
 150         }
 151         case 'q': {
 152             uint64_t val, *valp;
 153             valp = va_arg(ap, uint64_t *);
 154             val = le64_to_cpup(valp);
 155             offset += pdu_unpack(&val, pdu, offset, sizeof(val));
 156             *valp = val;
 157             break;
 158         }
 159         case 'v': {
 160             struct iovec *iov = va_arg(ap, struct iovec *);
 161             int *iovcnt = va_arg(ap, int *);
 162             *iovcnt = pdu_copy_sg(pdu, offset, 0, iov);
 163             break;
 164         }
 165         case 's': {
 166             V9fsString *str = va_arg(ap, V9fsString *);
 167             offset += pdu_unmarshal(pdu, offset, "w", &str->size);
 168             /* FIXME: sanity check str->size */
 169             str->data = qemu_malloc(str->size + 1);
 170             offset += pdu_unpack(str->data, pdu, offset, str->size);
 171             str->data[str->size] = 0;
 172             break;
 173         }
 174         case 'Q': {
 175             V9fsQID *qidp = va_arg(ap, V9fsQID *);
 176             offset += pdu_unmarshal(pdu, offset, "bdq",
 177                         &qidp->type, &qidp->version, &qidp->path);
 178             break;
 179         }
 180         case 'S': {
 181             V9fsStat *statp = va_arg(ap, V9fsStat *);
 182             offset += pdu_unmarshal(pdu, offset, "wwdQdddqsssssddd",
 183                         &statp->size, &statp->type, &statp->dev,
 184                         &statp->qid, &statp->mode, &statp->atime,
 185                         &statp->mtime, &statp->length,
 186                         &statp->name, &statp->uid, &statp->gid,
 187                         &statp->muid, &statp->extension,
 188                         &statp->n_uid, &statp->n_gid,
 189                         &statp->n_muid);
 190             break;
 191         }
 192         default:
 193             break;
 194         }
 195     }
 196
 197     va_end(ap);
 198
 199     return offset - old_offset;
 200 }
 201
 202 static size_t pdu_marshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...)
 203 {
 204     size_t old_offset = offset;
 205     va_list ap;
 206     int i;
 207
 208     va_start(ap, fmt);
 209     for (i = 0; fmt[i]; i++) {
 210         switch (fmt[i]) {
 211         case 'b': {
 212             uint8_t val = va_arg(ap, int);
 213             offset += pdu_pack(pdu, offset, &val, sizeof(val));
 214             break;
 215         }
 216         case 'w': {
 217             uint16_t val;
 218             cpu_to_le16w(&val, va_arg(ap, int));
 219             offset += pdu_pack(pdu, offset, &val, sizeof(val));
 220             break;
 221         }
 222         case 'd': {
 223             uint32_t val;
 224             cpu_to_le32w(&val, va_arg(ap, uint32_t));
 225             offset += pdu_pack(pdu, offset, &val, sizeof(val));
 226             break;
 227         }
 228         case 'q': {
 229             uint64_t val;
 230             cpu_to_le64w(&val, va_arg(ap, uint64_t));
 231             offset += pdu_pack(pdu, offset, &val, sizeof(val));
 232             break;
 233         }
 234         case 'v': {
 235             struct iovec *iov = va_arg(ap, struct iovec *);
 236             int *iovcnt = va_arg(ap, int *);
 237             *iovcnt = pdu_copy_sg(pdu, offset, 1, iov);
 238             break;
 239         }
 240         case 's': {
 241             V9fsString *str = va_arg(ap, V9fsString *);
 242             offset += pdu_marshal(pdu, offset, "w", str->size);
 243             offset += pdu_pack(pdu, offset, str->data, str->size);
 244             break;
 245         }
 246         case 'Q': {
 247             V9fsQID *qidp = va_arg(ap, V9fsQID *);
 248             offset += pdu_marshal(pdu, offset, "bdq",
 249                         qidp->type, qidp->version, qidp->path);
 250             break;
 251         }
 252         case 'S': {
 253             V9fsStat *statp = va_arg(ap, V9fsStat *);
 254             offset += pdu_marshal(pdu, offset, "wwdQdddqsssssddd",
 255                         statp->size, statp->type, statp->dev,
 256                         &statp->qid, statp->mode, statp->atime,
 257                         statp->mtime, statp->length, &statp->name,
 258                         &statp->uid, &statp->gid, &statp->muid,
 259                         &statp->extension, statp->n_uid,
 260                         statp->n_gid, statp->n_muid);
 261             break;
 262         }
 263         default:
 264             break;
 265         }
 266     }
 267     va_end(ap);
 268
 269     return offset - old_offset;
 270 }
 271
 272 static void complete_pdu(V9fsState *s, V9fsPDU *pdu, ssize_t len)
 273 {
 274     int8_t id = pdu->id + 1; /* Response */
 275
 276     if (len < 0) {
 277         V9fsString str;
 278         int err = -len;
 279
 280         str.data = strerror(err);
 281         str.size = strlen(str.data);
 282
 283         len = 7;
 284         len += pdu_marshal(pdu, len, "s", &str);
 285         if (dotu) {
 286             len += pdu_marshal(pdu, len, "d", err);
 287         }
 288
 289         id = P9_RERROR;
 290     }
 291
 292     /* fill out the header */
 293     pdu_marshal(pdu, 0, "dbw", (int32_t)len, id, pdu->tag);
 294
 295     /* keep these in sync */
 296     pdu->size = len;
 297     pdu->id = id;
 298
 299     /* push onto queue and notify */
 300     virtqueue_push(s->vq, &pdu->elem, len);
 301
 302     /* FIXME: we should batch these completions */
 303     virtio_notify(&s->vdev, s->vq);
 304
 305     free_pdu(s, pdu);
 306 }
 307
 308 static void v9fs_dummy(V9fsState *s, V9fsPDU *pdu)
 309 {
 310     /* Note: The following have been added to prevent GCC from complaining
 311      * They will be removed in the subsequent patches */
 312     (void)pdu_unmarshal;
 313     (void) complete_pdu;
 314
 315 }
 316 static void v9fs_version(V9fsState *s, V9fsPDU *pdu)
 317 {
 318     if (debug_9p_pdu) {
 319         pprint_pdu(pdu);
 320     }
 321 }
 322
 323 static void v9fs_attach(V9fsState *s, V9fsPDU *pdu)
 324 {
 325     if (debug_9p_pdu) {
 326         pprint_pdu(pdu);
 327     }
 328 }
 329
 330 static void v9fs_stat(V9fsState *s, V9fsPDU *pdu)
 331 {
 332     if (debug_9p_pdu) {
 333         pprint_pdu(pdu);
 334     }
 335 }
 336
 337 static void v9fs_walk(V9fsState *s, V9fsPDU *pdu)
 338 {
 339     if (debug_9p_pdu) {
 340         pprint_pdu(pdu);
 341     }
 342 }
 343
 344 static void v9fs_clunk(V9fsState *s, V9fsPDU *pdu)
 345 {
 346     if (debug_9p_pdu) {
 347         pprint_pdu(pdu);
 348     }
 349 }
 350
 351 static void v9fs_open(V9fsState *s, V9fsPDU *pdu)
 352 {    if (debug_9p_pdu) {
 353         pprint_pdu(pdu);
 354      }
 355 }
 356
 357 static void v9fs_read(V9fsState *s, V9fsPDU *pdu)
 358 {
 359     if (debug_9p_pdu) {
 360         pprint_pdu(pdu);
 361     }
 362 }
 363
 364 static void v9fs_write(V9fsState *s, V9fsPDU *pdu)
 365 {
 366     if (debug_9p_pdu) {
 367         pprint_pdu(pdu);
 368     }
 369 }
 370
 371 static void v9fs_create(V9fsState *s, V9fsPDU *pdu)
 372 {
 373     if (debug_9p_pdu) {
 374         pprint_pdu(pdu);
 375     }
 376 }
 377
 378 static void v9fs_flush(V9fsState *s, V9fsPDU *pdu)
 379 {
 380     v9fs_dummy(s, pdu);
 381     if (debug_9p_pdu) {
 382         pprint_pdu(pdu);
 383     }
 384 }
 385
 386 static void v9fs_remove(V9fsState *s, V9fsPDU *pdu)
 387 {
 388     if (debug_9p_pdu) {
 389         pprint_pdu(pdu);
 390     }
 391 }
 392
 393 static void v9fs_wstat(V9fsState *s, V9fsPDU *pdu)
 394 {
 395     if (debug_9p_pdu) {
 396         pprint_pdu(pdu);
 397     }
 398 }
 399
 400 typedef void (pdu_handler_t)(V9fsState *s, V9fsPDU *pdu);
 401
 402 static pdu_handler_t *pdu_handlers[] = {
 403     [P9_TVERSION] = v9fs_version,
 404     [P9_TATTACH] = v9fs_attach,
 405     [P9_TSTAT] = v9fs_stat,
 406     [P9_TWALK] = v9fs_walk,
 407     [P9_TCLUNK] = v9fs_clunk,
 408     [P9_TOPEN] = v9fs_open,
 409     [P9_TREAD] = v9fs_read,
 410 #if 0
 411     [P9_TAUTH] = v9fs_auth,
 412 #endif
 413     [P9_TFLUSH] = v9fs_flush,
 414     [P9_TCREATE] = v9fs_create,
 415     [P9_TWRITE] = v9fs_write,
 416     [P9_TWSTAT] = v9fs_wstat,
 417     [P9_TREMOVE] = v9fs_remove,
 418 };
 419
 420 static void submit_pdu(V9fsState *s, V9fsPDU *pdu)
 421 {
 422     pdu_handler_t *handler;
 423
 424     if (debug_9p_pdu) {
 425         pprint_pdu(pdu);
 426     }
 427
 428     BUG_ON(pdu->id >= ARRAY_SIZE(pdu_handlers));
 429
 430     handler = pdu_handlers[pdu->id];
 431     BUG_ON(handler == NULL);
 432
 433     handler(s, pdu);
 434 }
 435
 436 static void handle_9p_output(VirtIODevice *vdev, VirtQueue *vq)
 437 {
 438     V9fsState *s = (V9fsState *)vdev;
 439     V9fsPDU *pdu;
 440     ssize_t len;
 441
 442     while ((pdu = alloc_pdu(s)) &&
 443             (len = virtqueue_pop(vq, &pdu->elem)) != 0) {
 444         uint8_t *ptr;
 445
 446         BUG_ON(pdu->elem.out_num == 0 || pdu->elem.in_num == 0);
 447         BUG_ON(pdu->elem.out_sg[0].iov_len < 7);
 448
 449         ptr = pdu->elem.out_sg[0].iov_base;
 450
 451         memcpy(&pdu->size, ptr, 4);
 452         pdu->id = ptr[4];
 453         memcpy(&pdu->tag, ptr + 5, 2);
 454
 455         submit_pdu(s, pdu);
 456     }
 457
 458     free_pdu(s, pdu);
 459 }
 460
 461 static uint32_t virtio_9p_get_features(VirtIODevice *vdev, uint32_t features)
 462 {
 463     features |= 1 << VIRTIO_9P_MOUNT_TAG;
 464     return features;
 465 }
 466
 467 static V9fsState *to_virtio_9p(VirtIODevice *vdev)
 468 {
 469     return (V9fsState *)vdev;
 470 }
 471
 472 static void virtio_9p_get_config(VirtIODevice *vdev, uint8_t *config)
 473 {
 474     struct virtio_9p_config *cfg;
 475     V9fsState *s = to_virtio_9p(vdev);
 476
 477     cfg = qemu_mallocz(sizeof(struct virtio_9p_config) +
 478                         s->tag_len);
 479     stw_raw(&cfg->tag_len, s->tag_len);
 480     memcpy(cfg->tag, s->tag, s->tag_len);
 481     memcpy(config, cfg, s->config_size);
 482     qemu_free(cfg);
 483 }
 484
 485 VirtIODevice *virtio_9p_init(DeviceState *dev, V9fsConf *conf)
 486  {
 487     V9fsState *s;
 488     int i, len;
 489     struct stat stat;
 490     FsTypeEntry *fse;
 491
 492
 493     s = (V9fsState *)virtio_common_init("virtio-9p",
 494                                     VIRTIO_ID_9P,
 495                                     sizeof(struct virtio_9p_config)+
 496                                     MAX_TAG_LEN,
 497                                     sizeof(V9fsState));
 498
 499     /* initialize pdu allocator */
 500     QLIST_INIT(&s->free_list);
 501     for (i = 0; i < (MAX_REQ - 1); i++) {
 502         QLIST_INSERT_HEAD(&s->free_list, &s->pdus[i], next);
 503     }
 504
 505     s->vq = virtio_add_queue(&s->vdev, MAX_REQ, handle_9p_output);
 506
 507     fse = get_fsdev_fsentry(conf->fsdev_id);
 508
 509     if (!fse) {
 510         /* We don't have a fsdev identified by fsdev_id */
 511         fprintf(stderr, "Virtio-9p device couldn't find fsdev "
 512                     "with the id %s\n", conf->fsdev_id);
 513         exit(1);
 514     }
 515
 516     if (!fse->path || !conf->tag) {
 517         /* we haven't specified a mount_tag or the path */
 518         fprintf(stderr, "fsdev with id %s needs path "
 519                 "and Virtio-9p device needs mount_tag arguments\n",
 520                 conf->fsdev_id);
 521         exit(1);
 522     }
 523
 524     if (lstat(fse->path, &stat)) {
 525         fprintf(stderr, "share path %s does not exist\n", fse->path);
 526         exit(1);
 527     } else if (!S_ISDIR(stat.st_mode)) {
 528         fprintf(stderr, "share path %s is not a directory \n", fse->path);
 529         exit(1);
 530     }
 531
 532     s->ctx.fs_root = qemu_strdup(fse->path);
 533     len = strlen(conf->tag);
 534     if (len > MAX_TAG_LEN) {
 535         len = MAX_TAG_LEN;
 536     }
 537     /* s->tag is non-NULL terminated string */
 538     s->tag = qemu_malloc(len);
 539     memcpy(s->tag, conf->tag, len);
 540     s->tag_len = len;
 541     s->ctx.uid = -1;
 542
 543     s->ops = fse->ops;
 544     s->vdev.get_features = virtio_9p_get_features;
 545     s->config_size = sizeof(struct virtio_9p_config) +
 546                         s->tag_len;
 547     s->vdev.get_config = virtio_9p_get_config;
 548
 549     return &s->vdev;
 550 }