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                 curl_clean_state(state);
 233                 break;
 234             }
 235             default:
 236                 msgs_in_queue = 0;
 237                 break;
 238         }
 239     } while(msgs_in_queue);
 240 }
 241
 242 static CURLState *curl_init_state(BDRVCURLState *s)
 243 {
 244     CURLState *state = NULL;
 245     int i, j;
 246
 247     do {
 248         for (i=0; i<CURL_NUM_STATES; i++) {
 249             for (j=0; j<CURL_NUM_ACB; j++)
 250                 if (s->states[i].acb[j])
 251                     continue;
 252             if (s->states[i].in_use)
 253                 continue;
 254
 255             state = &s->states[i];
 256             state->in_use = 1;
 257             break;
 258         }
 259         if (!state) {
 260             usleep(100);
 261             curl_multi_do(s);
 262         }
 263     } while(!state);
 264
 265     if (state->curl)
 266         goto has_curl;
 267
 268     state->curl = curl_easy_init();
 269     if (!state->curl)
 270         return NULL;
 271     curl_easy_setopt(state->curl, CURLOPT_URL, s->url);
 272     curl_easy_setopt(state->curl, CURLOPT_TIMEOUT, 5);
 273     curl_easy_setopt(state->curl, CURLOPT_WRITEFUNCTION, (void *)curl_read_cb);
 274     curl_easy_setopt(state->curl, CURLOPT_WRITEDATA, (void *)state);
 275     curl_easy_setopt(state->curl, CURLOPT_PRIVATE, (void *)state);
 276     curl_easy_setopt(state->curl, CURLOPT_AUTOREFERER, 1);
 277     curl_easy_setopt(state->curl, CURLOPT_FOLLOWLOCATION, 1);
 278     curl_easy_setopt(state->curl, CURLOPT_NOSIGNAL, 1);
 279     curl_easy_setopt(state->curl, CURLOPT_ERRORBUFFER, state->errmsg);
 280
 281 #ifdef DEBUG_VERBOSE
 282     curl_easy_setopt(state->curl, CURLOPT_VERBOSE, 1);
 283 #endif
 284
 285 has_curl:
 286
 287     state->s = s;
 288
 289     return state;
 290 }
 291
 292 static void curl_clean_state(CURLState *s)
 293 {
 294     if (s->s->multi)
 295         curl_multi_remove_handle(s->s->multi, s->curl);
 296     s->in_use = 0;
 297 }
 298
 299 static int curl_open(BlockDriverState *bs, const char *filename, int flags)
 300 {
 301     BDRVCURLState *s = bs->opaque;
 302     CURLState *state = NULL;
 303     double d;
 304
 305     #define RA_OPTSTR ":readahead="
 306     char *file;
 307     char *ra;
 308     const char *ra_val;
 309     int parse_state = 0;
 310
 311     static int inited = 0;
 312
 313     file = qemu_strdup(filename);
 314     s->readahead_size = READ_AHEAD_SIZE;
 315
 316     /* Parse a trailing ":readahead=#:" param, if present. */
 317     ra = file + strlen(file) - 1;
 318     while (ra >= file) {
 319         if (parse_state == 0) {
 320             if (*ra == ':')
 321                 parse_state++;
 322             else
 323                 break;
 324         } else if (parse_state == 1) {
 325             if (*ra > '9' || *ra < '0') {
 326                 char *opt_start = ra - strlen(RA_OPTSTR) + 1;
 327                 if (opt_start > file &&
 328                     strncmp(opt_start, RA_OPTSTR, strlen(RA_OPTSTR)) == 0) {
 329                     ra_val = ra + 1;
 330                     ra -= strlen(RA_OPTSTR) - 1;
 331                     *ra = '\0';
 332                     s->readahead_size = atoi(ra_val);
 333                     break;
 334                 } else {
 335                     break;
 336                 }
 337             }
 338         }
 339         ra--;
 340     }
 341
 342     if ((s->readahead_size & 0x1ff) != 0) {
 343         fprintf(stderr, "HTTP_READAHEAD_SIZE %zd is not a multiple of 512\n",
 344                 s->readahead_size);
 345         goto out_noclean;
 346     }
 347
 348     if (!inited) {
 349         curl_global_init(CURL_GLOBAL_ALL);
 350         inited = 1;
 351     }
 352
 353     DPRINTF("CURL: Opening %s\n", file);
 354     s->url = file;
 355     state = curl_init_state(s);
 356     if (!state)
 357         goto out_noclean;
 358
 359     // Get file size
 360
 361     curl_easy_setopt(state->curl, CURLOPT_NOBODY, 1);
 362     curl_easy_setopt(state->curl, CURLOPT_WRITEFUNCTION, (void *)curl_size_cb);
 363     if (curl_easy_perform(state->curl))
 364         goto out;
 365     curl_easy_getinfo(state->curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &d);
 366     curl_easy_setopt(state->curl, CURLOPT_WRITEFUNCTION, (void *)curl_read_cb);
 367     curl_easy_setopt(state->curl, CURLOPT_NOBODY, 0);
 368     if (d)
 369         s->len = (size_t)d;
 370     else if(!s->len)
 371         goto out;
 372     DPRINTF("CURL: Size = %zd\n", s->len);
 373
 374     curl_clean_state(state);
 375     curl_easy_cleanup(state->curl);
 376     state->curl = NULL;
 377
 378     // Now we know the file exists and its size, so let's
 379     // initialize the multi interface!
 380
 381     s->multi = curl_multi_init();
 382     curl_multi_setopt( s->multi, CURLMOPT_SOCKETDATA, s);
 383     curl_multi_setopt( s->multi, CURLMOPT_SOCKETFUNCTION, curl_sock_cb );
 384     curl_multi_do(s);
 385
 386     return 0;
 387
 388 out:
 389     fprintf(stderr, "CURL: Error opening file: %s\n", state->errmsg);
 390     curl_easy_cleanup(state->curl);
 391     state->curl = NULL;
 392 out_noclean:
 393     qemu_free(file);
 394     return -EINVAL;
 395 }
 396
 397 static void curl_aio_cancel(BlockDriverAIOCB *blockacb)
 398 {
 399     // Do we have to implement canceling? Seems to work without...
 400 }
 401
 402 static AIOPool curl_aio_pool = {
 403     .aiocb_size         = sizeof(CURLAIOCB),
 404     .cancel             = curl_aio_cancel,
 405 };
 406
 407 static BlockDriverAIOCB *curl_aio_readv(BlockDriverState *bs,
 408         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 409         BlockDriverCompletionFunc *cb, void *opaque)
 410 {
 411     BDRVCURLState *s = bs->opaque;
 412     CURLAIOCB *acb;
 413     size_t start = sector_num * SECTOR_SIZE;
 414     size_t end;
 415     CURLState *state;
 416
 417     acb = qemu_aio_get(&curl_aio_pool, bs, cb, opaque);
 418     if (!acb)
 419         return NULL;
 420
 421     acb->qiov = qiov;
 422
 423     // In case we have the requested data already (e.g. read-ahead),
 424     // we can just call the callback and be done.
 425
 426     switch (curl_find_buf(s, start, nb_sectors * SECTOR_SIZE, acb)) {
 427         case FIND_RET_OK:
 428             qemu_aio_release(acb);
 429             // fall through
 430         case FIND_RET_WAIT:
 431             return &acb->common;
 432         default:
 433             break;
 434     }
 435
 436     // No cache found, so let's start a new request
 437
 438     state = curl_init_state(s);
 439     if (!state)
 440         return NULL;
 441
 442     acb->start = 0;
 443     acb->end = (nb_sectors * SECTOR_SIZE);
 444
 445     state->buf_off = 0;
 446     if (state->orig_buf)
 447         qemu_free(state->orig_buf);
 448     state->buf_start = start;
 449     state->buf_len = acb->end + s->readahead_size;
 450     end = MIN(start + state->buf_len, s->len) - 1;
 451     state->orig_buf = qemu_malloc(state->buf_len);
 452     state->acb[0] = acb;
 453
 454     snprintf(state->range, 127, "%zd-%zd", start, end);
 455     DPRINTF("CURL (AIO): Reading %d at %zd (%s)\n",
 456             (nb_sectors * SECTOR_SIZE), start, state->range);
 457     curl_easy_setopt(state->curl, CURLOPT_RANGE, state->range);
 458
 459     curl_multi_add_handle(s->multi, state->curl);
 460     curl_multi_do(s);
 461
 462     return &acb->common;
 463 }
 464
 465 static void curl_close(BlockDriverState *bs)
 466 {
 467     BDRVCURLState *s = bs->opaque;
 468     int i;
 469
 470     DPRINTF("CURL: Close\n");
 471     for (i=0; i<CURL_NUM_STATES; i++) {
 472         if (s->states[i].in_use)
 473             curl_clean_state(&s->states[i]);
 474         if (s->states[i].curl) {
 475             curl_easy_cleanup(s->states[i].curl);
 476             s->states[i].curl = NULL;
 477         }
 478         if (s->states[i].orig_buf) {
 479             qemu_free(s->states[i].orig_buf);
 480             s->states[i].orig_buf = NULL;
 481         }
 482     }
 483     if (s->multi)
 484         curl_multi_cleanup(s->multi);
 485     if (s->url)
 486         free(s->url);
 487 }
 488
 489 static int64_t curl_getlength(BlockDriverState *bs)
 490 {
 491     BDRVCURLState *s = bs->opaque;
 492     return s->len;
 493 }
 494
 495 static BlockDriver bdrv_http = {
 496     .format_name     = "http",
 497     .protocol_name   = "http",
 498
 499     .instance_size   = sizeof(BDRVCURLState),
 500     .bdrv_file_open  = curl_open,
 501     .bdrv_close      = curl_close,
 502     .bdrv_getlength  = curl_getlength,
 503
 504     .bdrv_aio_readv  = curl_aio_readv,
 505 };
 506
 507 static BlockDriver bdrv_https = {
 508     .format_name     = "https",
 509     .protocol_name   = "https",
 510
 511     .instance_size   = sizeof(BDRVCURLState),
 512     .bdrv_file_open  = curl_open,
 513     .bdrv_close      = curl_close,
 514     .bdrv_getlength  = curl_getlength,
 515
 516     .bdrv_aio_readv  = curl_aio_readv,
 517 };
 518
 519 static BlockDriver bdrv_ftp = {
 520     .format_name     = "ftp",
 521     .protocol_name   = "ftp",
 522
 523     .instance_size   = sizeof(BDRVCURLState),
 524     .bdrv_file_open  = curl_open,
 525     .bdrv_close      = curl_close,
 526     .bdrv_getlength  = curl_getlength,
 527
 528     .bdrv_aio_readv  = curl_aio_readv,
 529 };
 530
 531 static BlockDriver bdrv_ftps = {
 532     .format_name     = "ftps",
 533     .protocol_name   = "ftps",
 534
 535     .instance_size   = sizeof(BDRVCURLState),
 536     .bdrv_file_open  = curl_open,
 537     .bdrv_close      = curl_close,
 538     .bdrv_getlength  = curl_getlength,
 539
 540     .bdrv_aio_readv  = curl_aio_readv,
 541 };
 542
 543 static BlockDriver bdrv_tftp = {
 544     .format_name     = "tftp",
 545     .protocol_name   = "tftp",
 546
 547     .instance_size   = sizeof(BDRVCURLState),
 548     .bdrv_file_open  = curl_open,
 549     .bdrv_close      = curl_close,
 550     .bdrv_getlength  = curl_getlength,
 551
 552     .bdrv_aio_readv  = curl_aio_readv,
 553 };
 554
 555 static void curl_block_init(void)
 556 {
 557     bdrv_register(&bdrv_http);
 558     bdrv_register(&bdrv_https);
 559     bdrv_register(&bdrv_ftp);
 560     bdrv_register(&bdrv_ftps);
 561     bdrv_register(&bdrv_tftp);
 562 }
 563
 564 block_init(curl_block_init);