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, NULL, s);
  87             break;
  88         case CURL_POLL_OUT:
  89             qemu_aio_set_fd_handler(fd, NULL, curl_multi_do, NULL, NULL, s);
  90             break;
  91         case CURL_POLL_INOUT:
  92             qemu_aio_set_fd_handler(fd, curl_multi_do,
  93                                     curl_multi_do, NULL, NULL, s);
  94             break;
  95         case CURL_POLL_REMOVE:
  96             qemu_aio_set_fd_handler(fd, NULL, 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     size_t fsize;
 108
 109     if(sscanf(ptr, "Content-Length: %zd", &fsize) == 1) {
 110         s->s->len = fsize;
 111     }
 112
 113     return realsize;
 114 }
 115
 116 static size_t curl_read_cb(void *ptr, size_t size, size_t nmemb, void *opaque)
 117 {
 118     CURLState *s = ((CURLState*)opaque);
 119     size_t realsize = size * nmemb;
 120     int i;
 121
 122     DPRINTF("CURL: Just reading %zd bytes\n", realsize);
 123
 124     if (!s || !s->orig_buf)
 125         goto read_end;
 126
 127     memcpy(s->orig_buf + s->buf_off, ptr, realsize);
 128     s->buf_off += realsize;
 129
 130     for(i=0; i<CURL_NUM_ACB; i++) {
 131         CURLAIOCB *acb = s->acb[i];
 132
 133         if (!acb)
 134             continue;
 135
 136         if ((s->buf_off >= acb->end)) {
 137             qemu_iovec_from_buffer(acb->qiov, s->orig_buf + acb->start,
 138                                    acb->end - acb->start);
 139             acb->common.cb(acb->common.opaque, 0);
 140             qemu_aio_release(acb);
 141             s->acb[i] = NULL;
 142         }
 143     }
 144
 145 read_end:
 146     return realsize;
 147 }
 148
 149 static int curl_find_buf(BDRVCURLState *s, size_t start, size_t len,
 150                          CURLAIOCB *acb)
 151 {
 152     int i;
 153     size_t end = start + len;
 154
 155     for (i=0; i<CURL_NUM_STATES; i++) {
 156         CURLState *state = &s->states[i];
 157         size_t buf_end = (state->buf_start + state->buf_off);
 158         size_t buf_fend = (state->buf_start + state->buf_len);
 159
 160         if (!state->orig_buf)
 161             continue;
 162         if (!state->buf_off)
 163             continue;
 164
 165         // Does the existing buffer cover our section?
 166         if ((start >= state->buf_start) &&
 167             (start <= buf_end) &&
 168             (end >= state->buf_start) &&
 169             (end <= buf_end))
 170         {
 171             char *buf = state->orig_buf + (start - state->buf_start);
 172
 173             qemu_iovec_from_buffer(acb->qiov, buf, len);
 174             acb->common.cb(acb->common.opaque, 0);
 175
 176             return FIND_RET_OK;
 177         }
 178
 179         // Wait for unfinished chunks
 180         if ((start >= state->buf_start) &&
 181             (start <= buf_fend) &&
 182             (end >= state->buf_start) &&
 183             (end <= buf_fend))
 184         {
 185             int j;
 186
 187             acb->start = start - state->buf_start;
 188             acb->end = acb->start + len;
 189
 190             for (j=0; j<CURL_NUM_ACB; j++) {
 191                 if (!state->acb[j]) {
 192                     state->acb[j] = acb;
 193                     return FIND_RET_WAIT;
 194                 }
 195             }
 196         }
 197     }
 198
 199     return FIND_RET_NONE;
 200 }
 201
 202 static void curl_multi_do(void *arg)
 203 {
 204     BDRVCURLState *s = (BDRVCURLState *)arg;
 205     int running;
 206     int r;
 207     int msgs_in_queue;
 208
 209     if (!s->multi)
 210         return;
 211
 212     do {
 213         r = curl_multi_socket_all(s->multi, &running);
 214     } while(r == CURLM_CALL_MULTI_PERFORM);
 215
 216     /* Try to find done transfers, so we can free the easy
 217      * handle again. */
 218     do {
 219         CURLMsg *msg;
 220         msg = curl_multi_info_read(s->multi, &msgs_in_queue);
 221
 222         if (!msg)
 223             break;
 224         if (msg->msg == CURLMSG_NONE)
 225             break;
 226
 227         switch (msg->msg) {
 228             case CURLMSG_DONE:
 229             {
 230                 CURLState *state = NULL;
 231                 curl_easy_getinfo(msg->easy_handle, CURLINFO_PRIVATE, (char**)&state);
 232
 233                 /* ACBs for successful messages get completed in curl_read_cb */
 234                 if (msg->data.result != CURLE_OK) {
 235                     int i;
 236                     for (i = 0; i < CURL_NUM_ACB; i++) {
 237                         CURLAIOCB *acb = state->acb[i];
 238
 239                         if (acb == NULL) {
 240                             continue;
 241                         }
 242
 243                         acb->common.cb(acb->common.opaque, -EIO);
 244                         qemu_aio_release(acb);
 245                         state->acb[i] = NULL;
 246                     }
 247                 }
 248
 249                 curl_clean_state(state);
 250                 break;
 251             }
 252             default:
 253                 msgs_in_queue = 0;
 254                 break;
 255         }
 256     } while(msgs_in_queue);
 257 }
 258
 259 static CURLState *curl_init_state(BDRVCURLState *s)
 260 {
 261     CURLState *state = NULL;
 262     int i, j;
 263
 264     do {
 265         for (i=0; i<CURL_NUM_STATES; i++) {
 266             for (j=0; j<CURL_NUM_ACB; j++)
 267                 if (s->states[i].acb[j])
 268                     continue;
 269             if (s->states[i].in_use)
 270                 continue;
 271
 272             state = &s->states[i];
 273             state->in_use = 1;
 274             break;
 275         }
 276         if (!state) {
 277             usleep(100);
 278             curl_multi_do(s);
 279         }
 280     } while(!state);
 281
 282     if (state->curl)
 283         goto has_curl;
 284
 285     state->curl = curl_easy_init();
 286     if (!state->curl)
 287         return NULL;
 288     curl_easy_setopt(state->curl, CURLOPT_URL, s->url);
 289     curl_easy_setopt(state->curl, CURLOPT_TIMEOUT, 5);
 290     curl_easy_setopt(state->curl, CURLOPT_WRITEFUNCTION, (void *)curl_read_cb);
 291     curl_easy_setopt(state->curl, CURLOPT_WRITEDATA, (void *)state);
 292     curl_easy_setopt(state->curl, CURLOPT_PRIVATE, (void *)state);
 293     curl_easy_setopt(state->curl, CURLOPT_AUTOREFERER, 1);
 294     curl_easy_setopt(state->curl, CURLOPT_FOLLOWLOCATION, 1);
 295     curl_easy_setopt(state->curl, CURLOPT_NOSIGNAL, 1);
 296     curl_easy_setopt(state->curl, CURLOPT_ERRORBUFFER, state->errmsg);
 297     curl_easy_setopt(state->curl, CURLOPT_FAILONERROR, 1);
 298
 299 #ifdef DEBUG_VERBOSE
 300     curl_easy_setopt(state->curl, CURLOPT_VERBOSE, 1);
 301 #endif
 302
 303 has_curl:
 304
 305     state->s = s;
 306
 307     return state;
 308 }
 309
 310 static void curl_clean_state(CURLState *s)
 311 {
 312     if (s->s->multi)
 313         curl_multi_remove_handle(s->s->multi, s->curl);
 314     s->in_use = 0;
 315 }
 316
 317 static int curl_open(BlockDriverState *bs, const char *filename, int flags)
 318 {
 319     BDRVCURLState *s = bs->opaque;
 320     CURLState *state = NULL;
 321     double d;
 322
 323     #define RA_OPTSTR ":readahead="
 324     char *file;
 325     char *ra;
 326     const char *ra_val;
 327     int parse_state = 0;
 328
 329     static int inited = 0;
 330
 331     file = g_strdup(filename);
 332     s->readahead_size = READ_AHEAD_SIZE;
 333
 334     /* Parse a trailing ":readahead=#:" param, if present. */
 335     ra = file + strlen(file) - 1;
 336     while (ra >= file) {
 337         if (parse_state == 0) {
 338             if (*ra == ':')
 339                 parse_state++;
 340             else
 341                 break;
 342         } else if (parse_state == 1) {
 343             if (*ra > '9' || *ra < '0') {
 344                 char *opt_start = ra - strlen(RA_OPTSTR) + 1;
 345                 if (opt_start > file &&
 346                     strncmp(opt_start, RA_OPTSTR, strlen(RA_OPTSTR)) == 0) {
 347                     ra_val = ra + 1;
 348                     ra -= strlen(RA_OPTSTR) - 1;
 349                     *ra = '\0';
 350                     s->readahead_size = atoi(ra_val);
 351                     break;
 352                 } else {
 353                     break;
 354                 }
 355             }
 356         }
 357         ra--;
 358     }
 359
 360     if ((s->readahead_size & 0x1ff) != 0) {
 361         fprintf(stderr, "HTTP_READAHEAD_SIZE %zd is not a multiple of 512\n",
 362                 s->readahead_size);
 363         goto out_noclean;
 364     }
 365
 366     if (!inited) {
 367         curl_global_init(CURL_GLOBAL_ALL);
 368         inited = 1;
 369     }
 370
 371     DPRINTF("CURL: Opening %s\n", file);
 372     s->url = file;
 373     state = curl_init_state(s);
 374     if (!state)
 375         goto out_noclean;
 376
 377     // Get file size
 378
 379     curl_easy_setopt(state->curl, CURLOPT_NOBODY, 1);
 380     curl_easy_setopt(state->curl, CURLOPT_WRITEFUNCTION, (void *)curl_size_cb);
 381     if (curl_easy_perform(state->curl))
 382         goto out;
 383     curl_easy_getinfo(state->curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &d);
 384     curl_easy_setopt(state->curl, CURLOPT_WRITEFUNCTION, (void *)curl_read_cb);
 385     curl_easy_setopt(state->curl, CURLOPT_NOBODY, 0);
 386     if (d)
 387         s->len = (size_t)d;
 388     else if(!s->len)
 389         goto out;
 390     DPRINTF("CURL: Size = %zd\n", s->len);
 391
 392     curl_clean_state(state);
 393     curl_easy_cleanup(state->curl);
 394     state->curl = NULL;
 395
 396     // Now we know the file exists and its size, so let's
 397     // initialize the multi interface!
 398
 399     s->multi = curl_multi_init();
 400     curl_multi_setopt( s->multi, CURLMOPT_SOCKETDATA, s);
 401     curl_multi_setopt( s->multi, CURLMOPT_SOCKETFUNCTION, curl_sock_cb );
 402     curl_multi_do(s);
 403
 404     return 0;
 405
 406 out:
 407     fprintf(stderr, "CURL: Error opening file: %s\n", state->errmsg);
 408     curl_easy_cleanup(state->curl);
 409     state->curl = NULL;
 410 out_noclean:
 411     g_free(file);
 412     return -EINVAL;
 413 }
 414
 415 static void curl_aio_cancel(BlockDriverAIOCB *blockacb)
 416 {
 417     // Do we have to implement canceling? Seems to work without...
 418 }
 419
 420 static AIOPool curl_aio_pool = {
 421     .aiocb_size         = sizeof(CURLAIOCB),
 422     .cancel             = curl_aio_cancel,
 423 };
 424
 425 static BlockDriverAIOCB *curl_aio_readv(BlockDriverState *bs,
 426         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 427         BlockDriverCompletionFunc *cb, void *opaque)
 428 {
 429     BDRVCURLState *s = bs->opaque;
 430     CURLAIOCB *acb;
 431     size_t start = sector_num * SECTOR_SIZE;
 432     size_t end;
 433     CURLState *state;
 434
 435     acb = qemu_aio_get(&curl_aio_pool, bs, cb, opaque);
 436     if (!acb)
 437         return NULL;
 438
 439     acb->qiov = qiov;
 440
 441     // In case we have the requested data already (e.g. read-ahead),
 442     // we can just call the callback and be done.
 443
 444     switch (curl_find_buf(s, start, nb_sectors * SECTOR_SIZE, acb)) {
 445         case FIND_RET_OK:
 446             qemu_aio_release(acb);
 447             // fall through
 448         case FIND_RET_WAIT:
 449             return &acb->common;
 450         default:
 451             break;
 452     }
 453
 454     // No cache found, so let's start a new request
 455
 456     state = curl_init_state(s);
 457     if (!state)
 458         return NULL;
 459
 460     acb->start = 0;
 461     acb->end = (nb_sectors * SECTOR_SIZE);
 462
 463     state->buf_off = 0;
 464     if (state->orig_buf)
 465         g_free(state->orig_buf);
 466     state->buf_start = start;
 467     state->buf_len = acb->end + s->readahead_size;
 468     end = MIN(start + state->buf_len, s->len) - 1;
 469     state->orig_buf = g_malloc(state->buf_len);
 470     state->acb[0] = acb;
 471
 472     snprintf(state->range, 127, "%zd-%zd", start, end);
 473     DPRINTF("CURL (AIO): Reading %d at %zd (%s)\n",
 474             (nb_sectors * SECTOR_SIZE), start, state->range);
 475     curl_easy_setopt(state->curl, CURLOPT_RANGE, state->range);
 476
 477     curl_multi_add_handle(s->multi, state->curl);
 478     curl_multi_do(s);
 479
 480     return &acb->common;
 481 }
 482
 483 static void curl_close(BlockDriverState *bs)
 484 {
 485     BDRVCURLState *s = bs->opaque;
 486     int i;
 487
 488     DPRINTF("CURL: Close\n");
 489     for (i=0; i<CURL_NUM_STATES; i++) {
 490         if (s->states[i].in_use)
 491             curl_clean_state(&s->states[i]);
 492         if (s->states[i].curl) {
 493             curl_easy_cleanup(s->states[i].curl);
 494             s->states[i].curl = NULL;
 495         }
 496         if (s->states[i].orig_buf) {
 497             g_free(s->states[i].orig_buf);
 498             s->states[i].orig_buf = NULL;
 499         }
 500     }
 501     if (s->multi)
 502         curl_multi_cleanup(s->multi);
 503     if (s->url)
 504         free(s->url);
 505 }
 506
 507 static int64_t curl_getlength(BlockDriverState *bs)
 508 {
 509     BDRVCURLState *s = bs->opaque;
 510     return s->len;
 511 }
 512
 513 static BlockDriver bdrv_http = {
 514     .format_name     = "http",
 515     .protocol_name   = "http",
 516
 517     .instance_size   = sizeof(BDRVCURLState),
 518     .bdrv_file_open  = curl_open,
 519     .bdrv_close      = curl_close,
 520     .bdrv_getlength  = curl_getlength,
 521
 522     .bdrv_aio_readv  = curl_aio_readv,
 523 };
 524
 525 static BlockDriver bdrv_https = {
 526     .format_name     = "https",
 527     .protocol_name   = "https",
 528
 529     .instance_size   = sizeof(BDRVCURLState),
 530     .bdrv_file_open  = curl_open,
 531     .bdrv_close      = curl_close,
 532     .bdrv_getlength  = curl_getlength,
 533
 534     .bdrv_aio_readv  = curl_aio_readv,
 535 };
 536
 537 static BlockDriver bdrv_ftp = {
 538     .format_name     = "ftp",
 539     .protocol_name   = "ftp",
 540
 541     .instance_size   = sizeof(BDRVCURLState),
 542     .bdrv_file_open  = curl_open,
 543     .bdrv_close      = curl_close,
 544     .bdrv_getlength  = curl_getlength,
 545
 546     .bdrv_aio_readv  = curl_aio_readv,
 547 };
 548
 549 static BlockDriver bdrv_ftps = {
 550     .format_name     = "ftps",
 551     .protocol_name   = "ftps",
 552
 553     .instance_size   = sizeof(BDRVCURLState),
 554     .bdrv_file_open  = curl_open,
 555     .bdrv_close      = curl_close,
 556     .bdrv_getlength  = curl_getlength,
 557
 558     .bdrv_aio_readv  = curl_aio_readv,
 559 };
 560
 561 static BlockDriver bdrv_tftp = {
 562     .format_name     = "tftp",
 563     .protocol_name   = "tftp",
 564
 565     .instance_size   = sizeof(BDRVCURLState),
 566     .bdrv_file_open  = curl_open,
 567     .bdrv_close      = curl_close,
 568     .bdrv_getlength  = curl_getlength,
 569
 570     .bdrv_aio_readv  = curl_aio_readv,
 571 };
 572
 573 static void curl_block_init(void)
 574 {
 575     bdrv_register(&bdrv_http);
 576     bdrv_register(&bdrv_https);
 577     bdrv_register(&bdrv_ftp);
 578     bdrv_register(&bdrv_ftps);
 579     bdrv_register(&bdrv_tftp);
 580 }
 581
 582 block_init(curl_block_init);