block/curl.c

   1 /*
   2  * QEMU Block driver for CURL images
   3  *
   4  * Copyright (c) 2009 Alexander Graf <agraf@suse.de>
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24 #include "qemu-common.h"
  25 #include "block_int.h"
  26 #include <curl/curl.h>
  27
  28 // #define DEBUG
  29 // #define DEBUG_VERBOSE
  30
  31 #ifdef DEBUG_CURL
  32 #define dprintf(fmt, ...) do { printf(fmt, ## __VA_ARGS__); } while (0)
  33 #else
  34 #define dprintf(fmt, ...) do { } while (0)
  35 #endif
  36
  37 #define CURL_NUM_STATES 8
  38 #define CURL_NUM_ACB    8
  39 #define SECTOR_SIZE     512
  40 #define READ_AHEAD_SIZE (256 * 1024)
  41
  42 #define FIND_RET_NONE   0
  43 #define FIND_RET_OK     1
  44 #define FIND_RET_WAIT   2
  45
  46 struct BDRVCURLState;
  47
  48 typedef struct CURLAIOCB {
  49     BlockDriverAIOCB common;
  50     QEMUIOVector *qiov;
  51     size_t start;
  52     size_t end;
  53 } CURLAIOCB;
  54
  55 typedef struct CURLState
  56 {
  57     struct BDRVCURLState *s;
  58     CURLAIOCB *acb[CURL_NUM_ACB];
  59     CURL *curl;
  60     char *orig_buf;
  61     size_t buf_start;
  62     size_t buf_off;
  63     size_t buf_len;
  64     char range[128];
  65     char errmsg[CURL_ERROR_SIZE];
  66     char in_use;
  67 } CURLState;
  68
  69 typedef struct BDRVCURLState {
  70     CURLM *multi;
  71     size_t len;
  72     CURLState states[CURL_NUM_STATES];
  73     char *url;
  74     size_t readahead_size;
  75 } BDRVCURLState;
  76
  77 static void curl_clean_state(CURLState *s);
  78 static void curl_multi_do(void *arg);
  79
  80 static int curl_sock_cb(CURL *curl, curl_socket_t fd, int action,
  81                         void *s, void *sp)
  82 {
  83     dprintf("CURL (AIO): Sock action %d on fd %d\n", action, fd);
  84     switch (action) {
  85         case CURL_POLL_IN:
  86             qemu_aio_set_fd_handler(fd, curl_multi_do, NULL, NULL, s);
  87             break;
  88         case CURL_POLL_OUT:
  89             qemu_aio_set_fd_handler(fd, NULL, curl_multi_do, NULL, s);
  90             break;
  91         case CURL_POLL_INOUT:
  92             qemu_aio_set_fd_handler(fd, curl_multi_do,
  93                                     curl_multi_do, NULL, s);
  94             break;
  95         case CURL_POLL_REMOVE:
  96             qemu_aio_set_fd_handler(fd, NULL, NULL, NULL, NULL);
  97             break;
  98     }
  99
 100     return 0;
 101 }
 102
 103 static size_t curl_size_cb(void *ptr, size_t size, size_t nmemb, void *opaque)
 104 {
 105     CURLState *s = ((CURLState*)opaque);
 106     size_t realsize = size * nmemb;
 107     long long fsize;
 108
 109     if(sscanf(ptr, "Content-Length: %lld", &fsize) == 1)
 110         s->s->len = fsize;
 111
 112     return realsize;
 113 }
 114
 115 static size_t curl_read_cb(void *ptr, size_t size, size_t nmemb, void *opaque)
 116 {
 117     CURLState *s = ((CURLState*)opaque);
 118     size_t realsize = size * nmemb;
 119     int i;
 120
 121     dprintf("CURL: Just reading %lld bytes\n", (unsigned long long)realsize);
 122
 123     if (!s || !s->orig_buf)
 124         goto read_end;
 125
 126     memcpy(s->orig_buf + s->buf_off, ptr, realsize);
 127     s->buf_off += realsize;
 128
 129     for(i=0; i<CURL_NUM_ACB; i++) {
 130         CURLAIOCB *acb = s->acb[i];
 131
 132         if (!acb)
 133             continue;
 134
 135         if ((s->buf_off >= acb->end)) {
 136             qemu_iovec_from_buffer(acb->qiov, s->orig_buf + acb->start,
 137                                    acb->end - acb->start);
 138             acb->common.cb(acb->common.opaque, 0);
 139             qemu_aio_release(acb);
 140             s->acb[i] = NULL;
 141         }
 142     }
 143
 144 read_end:
 145     return realsize;
 146 }
 147
 148 static int curl_find_buf(BDRVCURLState *s, size_t start, size_t len,
 149                          CURLAIOCB *acb)
 150 {
 151     int i;
 152     size_t end = start + len;
 153
 154     for (i=0; i<CURL_NUM_STATES; i++) {
 155         CURLState *state = &s->states[i];
 156         size_t buf_end = (state->buf_start + state->buf_off);
 157         size_t buf_fend = (state->buf_start + state->buf_len);
 158
 159         if (!state->orig_buf)
 160             continue;
 161         if (!state->buf_off)
 162             continue;
 163
 164         // Does the existing buffer cover our section?
 165         if ((start >= state->buf_start) &&
 166             (start <= buf_end) &&
 167             (end >= state->buf_start) &&
 168             (end <= buf_end))
 169         {
 170             char *buf = state->orig_buf + (start - state->buf_start);
 171
 172             qemu_iovec_from_buffer(acb->qiov, buf, len);
 173             acb->common.cb(acb->common.opaque, 0);
 174
 175             return FIND_RET_OK;
 176         }
 177
 178         // Wait for unfinished chunks
 179         if ((start >= state->buf_start) &&
 180             (start <= buf_fend) &&
 181             (end >= state->buf_start) &&
 182             (end <= buf_fend))
 183         {
 184             int j;
 185
 186             acb->start = start - state->buf_start;
 187             acb->end = acb->start + len;
 188
 189             for (j=0; j<CURL_NUM_ACB; j++) {
 190                 if (!state->acb[j]) {
 191                     state->acb[j] = acb;
 192                     return FIND_RET_WAIT;
 193                 }
 194             }
 195         }
 196     }
 197
 198     return FIND_RET_NONE;
 199 }
 200
 201 static void curl_multi_do(void *arg)
 202 {
 203     BDRVCURLState *s = (BDRVCURLState *)arg;
 204     int running;
 205     int r;
 206     int msgs_in_queue;
 207
 208     if (!s->multi)
 209         return;
 210
 211     do {
 212         r = curl_multi_socket_all(s->multi, &running);
 213     } while(r == CURLM_CALL_MULTI_PERFORM);
 214
 215     /* Try to find done transfers, so we can free the easy
 216      * handle again. */
 217     do {
 218         CURLMsg *msg;
 219         msg = curl_multi_info_read(s->multi, &msgs_in_queue);
 220
 221         if (!msg)
 222             break;
 223         if (msg->msg == CURLMSG_NONE)
 224             break;
 225
 226         switch (msg->msg) {
 227             case CURLMSG_DONE:
 228             {
 229                 CURLState *state = NULL;
 230                 curl_easy_getinfo(msg->easy_handle, CURLINFO_PRIVATE, (char**)&state);
 231                 curl_clean_state(state);
 232                 break;
 233             }
 234             default:
 235                 msgs_in_queue = 0;
 236                 break;
 237         }
 238     } while(msgs_in_queue);
 239 }
 240
 241 static CURLState *curl_init_state(BDRVCURLState *s)
 242 {
 243     CURLState *state = NULL;
 244     int i, j;
 245
 246     do {
 247         for (i=0; i<CURL_NUM_STATES; i++) {
 248             for (j=0; j<CURL_NUM_ACB; j++)
 249                 if (s->states[i].acb[j])
 250                     continue;
 251             if (s->states[i].in_use)
 252                 continue;
 253
 254             state = &s->states[i];
 255             state->in_use = 1;
 256             break;
 257         }
 258         if (!state) {
 259             usleep(100);
 260             curl_multi_do(s);
 261         }
 262     } while(!state);
 263
 264     if (state->curl)
 265         goto has_curl;
 266
 267     state->curl = curl_easy_init();
 268     if (!state->curl)
 269         return NULL;
 270     curl_easy_setopt(state->curl, CURLOPT_URL, s->url);
 271     curl_easy_setopt(state->curl, CURLOPT_TIMEOUT, 5);
 272     curl_easy_setopt(state->curl, CURLOPT_WRITEFUNCTION, curl_read_cb);
 273     curl_easy_setopt(state->curl, CURLOPT_WRITEDATA, (void *)state);
 274     curl_easy_setopt(state->curl, CURLOPT_PRIVATE, (void *)state);
 275     curl_easy_setopt(state->curl, CURLOPT_AUTOREFERER, 1);
 276     curl_easy_setopt(state->curl, CURLOPT_FOLLOWLOCATION, 1);
 277     curl_easy_setopt(state->curl, CURLOPT_NOSIGNAL, 1);
 278     curl_easy_setopt(state->curl, CURLOPT_ERRORBUFFER, state->errmsg);
 279
 280 #ifdef DEBUG_VERBOSE
 281     curl_easy_setopt(state->curl, CURLOPT_VERBOSE, 1);
 282 #endif
 283
 284 has_curl:
 285
 286     state->s = s;
 287
 288     return state;
 289 }
 290
 291 static void curl_clean_state(CURLState *s)
 292 {
 293     if (s->s->multi)
 294         curl_multi_remove_handle(s->s->multi, s->curl);
 295     s->in_use = 0;
 296 }
 297
 298 static int curl_open(BlockDriverState *bs, const char *filename, int flags)
 299 {
 300     BDRVCURLState *s = bs->opaque;
 301     CURLState *state = NULL;
 302     double d;
 303
 304     #define RA_OPTSTR ":readahead="
 305     char *file;
 306     char *ra;
 307     const char *ra_val;
 308     int parse_state = 0;
 309
 310     static int inited = 0;
 311
 312     file = strdup(filename);
 313     s->readahead_size = READ_AHEAD_SIZE;
 314
 315     /* Parse a trailing ":readahead=#:" param, if present. */
 316     ra = file + strlen(file) - 1;
 317     while (ra >= file) {
 318         if (parse_state == 0) {
 319             if (*ra == ':')
 320                 parse_state++;
 321             else
 322                 break;
 323         } else if (parse_state == 1) {
 324             if (*ra > '9' || *ra < '0') {
 325                 char *opt_start = ra - strlen(RA_OPTSTR) + 1;
 326                 if (opt_start > file &&
 327                     strncmp(opt_start, RA_OPTSTR, strlen(RA_OPTSTR)) == 0) {
 328                     ra_val = ra + 1;
 329                     ra -= strlen(RA_OPTSTR) - 1;
 330                     *ra = '\0';
 331                     s->readahead_size = atoi(ra_val);
 332                     break;
 333                 } else {
 334                     break;
 335                 }
 336             }
 337         }
 338         ra--;
 339     }
 340
 341     if ((s->readahead_size & 0x1ff) != 0) {
 342         fprintf(stderr, "HTTP_READAHEAD_SIZE %Zd is not a multiple of 512\n",
 343                 s->readahead_size);
 344         goto out_noclean;
 345     }
 346
 347     if (!inited) {
 348         curl_global_init(CURL_GLOBAL_ALL);
 349         inited = 1;
 350     }
 351
 352     dprintf("CURL: Opening %s\n", file);
 353     s->url = file;
 354     state = curl_init_state(s);
 355     if (!state)
 356         goto out_noclean;
 357
 358     // Get file size
 359
 360     curl_easy_setopt(state->curl, CURLOPT_NOBODY, 1);
 361     curl_easy_setopt(state->curl, CURLOPT_WRITEFUNCTION, curl_size_cb);
 362     if (curl_easy_perform(state->curl))
 363         goto out;
 364     curl_easy_getinfo(state->curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &d);
 365     curl_easy_setopt(state->curl, CURLOPT_WRITEFUNCTION, curl_read_cb);
 366     curl_easy_setopt(state->curl, CURLOPT_NOBODY, 0);
 367     if (d)
 368         s->len = (size_t)d;
 369     else if(!s->len)
 370         goto out;
 371     dprintf("CURL: Size = %lld\n", (long long)s->len);
 372
 373     curl_clean_state(state);
 374     curl_easy_cleanup(state->curl);
 375     state->curl = NULL;
 376
 377     // Now we know the file exists and its size, so let's
 378     // initialize the multi interface!
 379
 380     s->multi = curl_multi_init();
 381     curl_multi_setopt( s->multi, CURLMOPT_SOCKETDATA, s);
 382     curl_multi_setopt( s->multi, CURLMOPT_SOCKETFUNCTION, curl_sock_cb );
 383     curl_multi_do(s);
 384
 385     return 0;
 386
 387 out:
 388     fprintf(stderr, "CURL: Error opening file: %s\n", state->errmsg);
 389     curl_easy_cleanup(state->curl);
 390     state->curl = NULL;
 391 out_noclean:
 392     qemu_free(file);
 393     return -EINVAL;
 394 }
 395
 396 static void curl_aio_cancel(BlockDriverAIOCB *blockacb)
 397 {
 398     // Do we have to implement canceling? Seems to work without...
 399 }
 400
 401 static AIOPool curl_aio_pool = {
 402     .aiocb_size         = sizeof(CURLAIOCB),
 403     .cancel             = curl_aio_cancel,
 404 };
 405
 406 static BlockDriverAIOCB *curl_aio_readv(BlockDriverState *bs,
 407         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 408         BlockDriverCompletionFunc *cb, void *opaque)
 409 {
 410     BDRVCURLState *s = bs->opaque;
 411     CURLAIOCB *acb;
 412     size_t start = sector_num * SECTOR_SIZE;
 413     size_t end;
 414     CURLState *state;
 415
 416     acb = qemu_aio_get(&curl_aio_pool, bs, cb, opaque);
 417     if (!acb)
 418         return NULL;
 419
 420     acb->qiov = qiov;
 421
 422     // In case we have the requested data already (e.g. read-ahead),
 423     // we can just call the callback and be done.
 424
 425     switch (curl_find_buf(s, start, nb_sectors * SECTOR_SIZE, acb)) {
 426         case FIND_RET_OK:
 427             qemu_aio_release(acb);
 428             // fall through
 429         case FIND_RET_WAIT:
 430             return &acb->common;
 431         default:
 432             break;
 433     }
 434
 435     // No cache found, so let's start a new request
 436
 437     state = curl_init_state(s);
 438     if (!state)
 439         return NULL;
 440
 441     acb->start = 0;
 442     acb->end = (nb_sectors * SECTOR_SIZE);
 443
 444     state->buf_off = 0;
 445     if (state->orig_buf)
 446         qemu_free(state->orig_buf);
 447     state->buf_start = start;
 448     state->buf_len = acb->end + s->readahead_size;
 449     end = MIN(start + state->buf_len, s->len) - 1;
 450     state->orig_buf = qemu_malloc(state->buf_len);
 451     state->acb[0] = acb;
 452
 453     snprintf(state->range, 127, "%lld-%lld", (long long)start, (long long)end);
 454     dprintf("CURL (AIO): Reading %d at %lld (%s)\n", (nb_sectors * SECTOR_SIZE), start, state->range);
 455     curl_easy_setopt(state->curl, CURLOPT_RANGE, state->range);
 456
 457     curl_multi_add_handle(s->multi, state->curl);
 458     curl_multi_do(s);
 459
 460     return &acb->common;
 461 }
 462
 463 static void curl_close(BlockDriverState *bs)
 464 {
 465     BDRVCURLState *s = bs->opaque;
 466     int i;
 467
 468     dprintf("CURL: Close\n");
 469     for (i=0; i<CURL_NUM_STATES; i++) {
 470         if (s->states[i].in_use)
 471             curl_clean_state(&s->states[i]);
 472         if (s->states[i].curl) {
 473             curl_easy_cleanup(s->states[i].curl);
 474             s->states[i].curl = NULL;
 475         }
 476         if (s->states[i].orig_buf) {
 477             qemu_free(s->states[i].orig_buf);
 478             s->states[i].orig_buf = NULL;
 479         }
 480     }
 481     if (s->multi)
 482         curl_multi_cleanup(s->multi);
 483     if (s->url)
 484         free(s->url);
 485 }
 486
 487 static int64_t curl_getlength(BlockDriverState *bs)
 488 {
 489     BDRVCURLState *s = bs->opaque;
 490     return s->len;
 491 }
 492
 493 static BlockDriver bdrv_http = {
 494     .format_name     = "http",
 495     .protocol_name   = "http",
 496
 497     .instance_size   = sizeof(BDRVCURLState),
 498     .bdrv_open       = curl_open,
 499     .bdrv_close      = curl_close,
 500     .bdrv_getlength  = curl_getlength,
 501
 502     .bdrv_aio_readv  = curl_aio_readv,
 503 };
 504
 505 static BlockDriver bdrv_https = {
 506     .format_name     = "https",
 507     .protocol_name   = "https",
 508
 509     .instance_size   = sizeof(BDRVCURLState),
 510     .bdrv_open       = curl_open,
 511     .bdrv_close      = curl_close,
 512     .bdrv_getlength  = curl_getlength,
 513
 514     .bdrv_aio_readv  = curl_aio_readv,
 515 };
 516
 517 static BlockDriver bdrv_ftp = {
 518     .format_name     = "ftp",
 519     .protocol_name   = "ftp",
 520
 521     .instance_size   = sizeof(BDRVCURLState),
 522     .bdrv_open       = curl_open,
 523     .bdrv_close      = curl_close,
 524     .bdrv_getlength  = curl_getlength,
 525
 526     .bdrv_aio_readv  = curl_aio_readv,
 527 };
 528
 529 static BlockDriver bdrv_ftps = {
 530     .format_name     = "ftps",
 531     .protocol_name   = "ftps",
 532
 533     .instance_size   = sizeof(BDRVCURLState),
 534     .bdrv_open       = curl_open,
 535     .bdrv_close      = curl_close,
 536     .bdrv_getlength  = curl_getlength,
 537
 538     .bdrv_aio_readv  = curl_aio_readv,
 539 };
 540
 541 static BlockDriver bdrv_tftp = {
 542     .format_name     = "tftp",
 543     .protocol_name   = "tftp",
 544
 545     .instance_size   = sizeof(BDRVCURLState),
 546     .bdrv_open       = curl_open,
 547     .bdrv_close      = curl_close,
 548     .bdrv_getlength  = curl_getlength,
 549
 550     .bdrv_aio_readv  = curl_aio_readv,
 551 };
 552
 553 static void curl_block_init(void)
 554 {
 555     bdrv_register(&bdrv_http);
 556     bdrv_register(&bdrv_https);
 557     bdrv_register(&bdrv_ftp);
 558     bdrv_register(&bdrv_ftps);
 559     bdrv_register(&bdrv_tftp);
 560 }
 561
 562 block_init(curl_block_init);