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 } BDRVCURLState;
  75
  76 static void curl_clean_state(CURLState *s);
  77 static void curl_multi_do(void *arg);
  78
  79 static int curl_sock_cb(CURL *curl, curl_socket_t fd, int action,
  80                         void *s, void *sp)
  81 {
  82     dprintf("CURL (AIO): Sock action %d on fd %d\n", action, fd);
  83     switch (action) {
  84         case CURL_POLL_IN:
  85             qemu_aio_set_fd_handler(fd, curl_multi_do, NULL, NULL, s);
  86             break;
  87         case CURL_POLL_OUT:
  88             qemu_aio_set_fd_handler(fd, NULL, curl_multi_do, NULL, s);
  89             break;
  90         case CURL_POLL_INOUT:
  91             qemu_aio_set_fd_handler(fd, curl_multi_do,
  92                                     curl_multi_do, NULL, s);
  93             break;
  94         case CURL_POLL_REMOVE:
  95             qemu_aio_set_fd_handler(fd, NULL, NULL, NULL, NULL);
  96             break;
  97     }
  98
  99     return 0;
 100 }
 101
 102 static size_t curl_size_cb(void *ptr, size_t size, size_t nmemb, void *opaque)
 103 {
 104     CURLState *s = ((CURLState*)opaque);
 105     size_t realsize = size * nmemb;
 106     long long fsize;
 107
 108     if(sscanf(ptr, "Content-Length: %lld", &fsize) == 1)
 109         s->s->len = fsize;
 110
 111     return realsize;
 112 }
 113
 114 static size_t curl_read_cb(void *ptr, size_t size, size_t nmemb, void *opaque)
 115 {
 116     CURLState *s = ((CURLState*)opaque);
 117     size_t realsize = size * nmemb;
 118     int i;
 119
 120     dprintf("CURL: Just reading %lld bytes\n", (unsigned long long)realsize);
 121
 122     if (!s || !s->orig_buf)
 123         goto read_end;
 124
 125     memcpy(s->orig_buf + s->buf_off, ptr, realsize);
 126     s->buf_off += realsize;
 127
 128     for(i=0; i<CURL_NUM_ACB; i++) {
 129         CURLAIOCB *acb = s->acb[i];
 130
 131         if (!acb)
 132             continue;
 133
 134         if ((s->buf_off >= acb->end)) {
 135             qemu_iovec_from_buffer(acb->qiov, s->orig_buf + acb->start,
 136                                    acb->end - acb->start);
 137             acb->common.cb(acb->common.opaque, 0);
 138             qemu_aio_release(acb);
 139             s->acb[i] = NULL;
 140         }
 141     }
 142
 143 read_end:
 144     return realsize;
 145 }
 146
 147 static int curl_find_buf(BDRVCURLState *s, size_t start, size_t len,
 148                          CURLAIOCB *acb)
 149 {
 150     int i;
 151     size_t end = start + len;
 152
 153     for (i=0; i<CURL_NUM_STATES; i++) {
 154         CURLState *state = &s->states[i];
 155         size_t buf_end = (state->buf_start + state->buf_off);
 156         size_t buf_fend = (state->buf_start + state->buf_len);
 157
 158         if (!state->orig_buf)
 159             continue;
 160         if (!state->buf_off)
 161             continue;
 162
 163         // Does the existing buffer cover our section?
 164         if ((start >= state->buf_start) &&
 165             (start <= buf_end) &&
 166             (end >= state->buf_start) &&
 167             (end <= buf_end))
 168         {
 169             char *buf = state->orig_buf + (start - state->buf_start);
 170
 171             qemu_iovec_from_buffer(acb->qiov, buf, len);
 172             acb->common.cb(acb->common.opaque, 0);
 173
 174             return FIND_RET_OK;
 175         }
 176
 177         // Wait for unfinished chunks
 178         if ((start >= state->buf_start) &&
 179             (start <= buf_fend) &&
 180             (end >= state->buf_start) &&
 181             (end <= buf_fend))
 182         {
 183             int j;
 184
 185             acb->start = start - state->buf_start;
 186             acb->end = acb->start + len;
 187
 188             for (j=0; j<CURL_NUM_ACB; j++) {
 189                 if (!state->acb[j]) {
 190                     state->acb[j] = acb;
 191                     return FIND_RET_WAIT;
 192                 }
 193             }
 194         }
 195     }
 196
 197     return FIND_RET_NONE;
 198 }
 199
 200 static void curl_multi_do(void *arg)
 201 {
 202     BDRVCURLState *s = (BDRVCURLState *)arg;
 203     int running;
 204     int r;
 205     int msgs_in_queue;
 206
 207     if (!s->multi)
 208         return;
 209
 210     do {
 211         r = curl_multi_socket_all(s->multi, &running);
 212     } while(r == CURLM_CALL_MULTI_PERFORM);
 213
 214     /* Try to find done transfers, so we can free the easy
 215      * handle again. */
 216     do {
 217         CURLMsg *msg;
 218         msg = curl_multi_info_read(s->multi, &msgs_in_queue);
 219
 220         if (!msg)
 221             break;
 222         if (msg->msg == CURLMSG_NONE)
 223             break;
 224
 225         switch (msg->msg) {
 226             case CURLMSG_DONE:
 227             {
 228                 CURLState *state = NULL;
 229                 curl_easy_getinfo(msg->easy_handle, CURLINFO_PRIVATE, (char**)&state);
 230                 curl_clean_state(state);
 231                 break;
 232             }
 233             default:
 234                 msgs_in_queue = 0;
 235                 break;
 236         }
 237     } while(msgs_in_queue);
 238 }
 239
 240 static CURLState *curl_init_state(BDRVCURLState *s)
 241 {
 242     CURLState *state = NULL;
 243     int i, j;
 244
 245     do {
 246         for (i=0; i<CURL_NUM_STATES; i++) {
 247             for (j=0; j<CURL_NUM_ACB; j++)
 248                 if (s->states[i].acb[j])
 249                     continue;
 250             if (s->states[i].in_use)
 251                 continue;
 252
 253             state = &s->states[i];
 254             state->in_use = 1;
 255             break;
 256         }
 257         if (!state) {
 258             usleep(100);
 259             curl_multi_do(s);
 260         }
 261     } while(!state);
 262
 263     if (state->curl)
 264         goto has_curl;
 265
 266     state->curl = curl_easy_init();
 267     if (!state->curl)
 268         return NULL;
 269     curl_easy_setopt(state->curl, CURLOPT_URL, s->url);
 270     curl_easy_setopt(state->curl, CURLOPT_TIMEOUT, 5);
 271     curl_easy_setopt(state->curl, CURLOPT_WRITEFUNCTION, curl_read_cb);
 272     curl_easy_setopt(state->curl, CURLOPT_WRITEDATA, (void *)state);
 273     curl_easy_setopt(state->curl, CURLOPT_PRIVATE, (void *)state);
 274     curl_easy_setopt(state->curl, CURLOPT_AUTOREFERER, 1);
 275     curl_easy_setopt(state->curl, CURLOPT_FOLLOWLOCATION, 1);
 276     curl_easy_setopt(state->curl, CURLOPT_NOSIGNAL, 1);
 277     curl_easy_setopt(state->curl, CURLOPT_ERRORBUFFER, state->errmsg);
 278
 279 #ifdef DEBUG_VERBOSE
 280     curl_easy_setopt(state->curl, CURLOPT_VERBOSE, 1);
 281 #endif
 282
 283 has_curl:
 284
 285     state->s = s;
 286
 287     return state;
 288 }
 289
 290 static void curl_clean_state(CURLState *s)
 291 {
 292     if (s->s->multi)
 293         curl_multi_remove_handle(s->s->multi, s->curl);
 294     s->in_use = 0;
 295 }
 296
 297 static int curl_open(BlockDriverState *bs, const char *filename, int flags)
 298 {
 299     BDRVCURLState *s = bs->opaque;
 300     CURLState *state = NULL;
 301     double d;
 302     static int inited = 0;
 303
 304     if (!inited) {
 305         curl_global_init(CURL_GLOBAL_ALL);
 306         inited = 1;
 307     }
 308
 309     dprintf("CURL: Opening %s\n", filename);
 310     s->url = strdup(filename);
 311     state = curl_init_state(s);
 312     if (!state)
 313         goto out_noclean;
 314
 315     // Get file size
 316
 317     curl_easy_setopt(state->curl, CURLOPT_NOBODY, 1);
 318     curl_easy_setopt(state->curl, CURLOPT_WRITEFUNCTION, curl_size_cb);
 319     if (curl_easy_perform(state->curl))
 320         goto out;
 321     curl_easy_getinfo(state->curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &d);
 322     curl_easy_setopt(state->curl, CURLOPT_WRITEFUNCTION, curl_read_cb);
 323     curl_easy_setopt(state->curl, CURLOPT_NOBODY, 0);
 324     if (d)
 325         s->len = (size_t)d;
 326     else if(!s->len)
 327         goto out;
 328     dprintf("CURL: Size = %lld\n", (long long)s->len);
 329
 330     curl_clean_state(state);
 331     curl_easy_cleanup(state->curl);
 332     state->curl = NULL;
 333
 334     // Now we know the file exists and its size, so let's
 335     // initialize the multi interface!
 336
 337     s->multi = curl_multi_init();
 338     curl_multi_setopt( s->multi, CURLMOPT_SOCKETDATA, s);
 339     curl_multi_setopt( s->multi, CURLMOPT_SOCKETFUNCTION, curl_sock_cb );
 340     curl_multi_do(s);
 341
 342     return 0;
 343
 344 out:
 345     fprintf(stderr, "CURL: Error opening file: %s\n", state->errmsg);
 346     curl_easy_cleanup(state->curl);
 347     state->curl = NULL;
 348 out_noclean:
 349     return -EINVAL;
 350 }
 351
 352 static void curl_aio_cancel(BlockDriverAIOCB *blockacb)
 353 {
 354     // Do we have to implement canceling? Seems to work without...
 355 }
 356
 357 static AIOPool curl_aio_pool = {
 358     .aiocb_size         = sizeof(CURLAIOCB),
 359     .cancel             = curl_aio_cancel,
 360 };
 361
 362 static BlockDriverAIOCB *curl_aio_readv(BlockDriverState *bs,
 363         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 364         BlockDriverCompletionFunc *cb, void *opaque)
 365 {
 366     BDRVCURLState *s = bs->opaque;
 367     CURLAIOCB *acb;
 368     size_t start = sector_num * SECTOR_SIZE;
 369     size_t end;
 370     CURLState *state;
 371
 372     acb = qemu_aio_get(&curl_aio_pool, bs, cb, opaque);
 373     if (!acb)
 374         return NULL;
 375
 376     acb->qiov = qiov;
 377
 378     // In case we have the requested data already (e.g. read-ahead),
 379     // we can just call the callback and be done.
 380
 381     switch (curl_find_buf(s, start, nb_sectors * SECTOR_SIZE, acb)) {
 382         case FIND_RET_OK:
 383             qemu_aio_release(acb);
 384             // fall through
 385         case FIND_RET_WAIT:
 386             return &acb->common;
 387         default:
 388             break;
 389     }
 390
 391     // No cache found, so let's start a new request
 392
 393     state = curl_init_state(s);
 394     if (!state)
 395         return NULL;
 396
 397     acb->start = 0;
 398     acb->end = (nb_sectors * SECTOR_SIZE);
 399
 400     state->buf_off = 0;
 401     if (state->orig_buf)
 402         qemu_free(state->orig_buf);
 403     state->buf_start = start;
 404     state->buf_len = acb->end + READ_AHEAD_SIZE;
 405     end = MIN(start + state->buf_len, s->len) - 1;
 406     state->orig_buf = qemu_malloc(state->buf_len);
 407     state->acb[0] = acb;
 408
 409     snprintf(state->range, 127, "%lld-%lld", (long long)start, (long long)end);
 410     dprintf("CURL (AIO): Reading %d at %lld (%s)\n", (nb_sectors * SECTOR_SIZE), start, state->range);
 411     curl_easy_setopt(state->curl, CURLOPT_RANGE, state->range);
 412
 413     curl_multi_add_handle(s->multi, state->curl);
 414     curl_multi_do(s);
 415
 416     return &acb->common;
 417 }
 418
 419 static void curl_close(BlockDriverState *bs)
 420 {
 421     BDRVCURLState *s = bs->opaque;
 422     int i;
 423
 424     dprintf("CURL: Close\n");
 425     for (i=0; i<CURL_NUM_STATES; i++) {
 426         if (s->states[i].in_use)
 427             curl_clean_state(&s->states[i]);
 428         if (s->states[i].curl) {
 429             curl_easy_cleanup(s->states[i].curl);
 430             s->states[i].curl = NULL;
 431         }
 432         if (s->states[i].orig_buf) {
 433             qemu_free(s->states[i].orig_buf);
 434             s->states[i].orig_buf = NULL;
 435         }
 436     }
 437     if (s->multi)
 438         curl_multi_cleanup(s->multi);
 439     if (s->url)
 440         free(s->url);
 441 }
 442
 443 static int64_t curl_getlength(BlockDriverState *bs)
 444 {
 445     BDRVCURLState *s = bs->opaque;
 446     return s->len;
 447 }
 448
 449 static BlockDriver bdrv_http = {
 450     .format_name     = "http",
 451     .protocol_name   = "http",
 452
 453     .instance_size   = sizeof(BDRVCURLState),
 454     .bdrv_open       = curl_open,
 455     .bdrv_close      = curl_close,
 456     .bdrv_getlength  = curl_getlength,
 457
 458     .bdrv_aio_readv  = curl_aio_readv,
 459 };
 460
 461 static BlockDriver bdrv_https = {
 462     .format_name     = "https",
 463     .protocol_name   = "https",
 464
 465     .instance_size   = sizeof(BDRVCURLState),
 466     .bdrv_open       = curl_open,
 467     .bdrv_close      = curl_close,
 468     .bdrv_getlength  = curl_getlength,
 469
 470     .bdrv_aio_readv  = curl_aio_readv,
 471 };
 472
 473 static BlockDriver bdrv_ftp = {
 474     .format_name     = "ftp",
 475     .protocol_name   = "ftp",
 476
 477     .instance_size   = sizeof(BDRVCURLState),
 478     .bdrv_open       = curl_open,
 479     .bdrv_close      = curl_close,
 480     .bdrv_getlength  = curl_getlength,
 481
 482     .bdrv_aio_readv  = curl_aio_readv,
 483 };
 484
 485 static BlockDriver bdrv_ftps = {
 486     .format_name     = "ftps",
 487     .protocol_name   = "ftps",
 488
 489     .instance_size   = sizeof(BDRVCURLState),
 490     .bdrv_open       = curl_open,
 491     .bdrv_close      = curl_close,
 492     .bdrv_getlength  = curl_getlength,
 493
 494     .bdrv_aio_readv  = curl_aio_readv,
 495 };
 496
 497 static BlockDriver bdrv_tftp = {
 498     .format_name     = "tftp",
 499     .protocol_name   = "tftp",
 500
 501     .instance_size   = sizeof(BDRVCURLState),
 502     .bdrv_open       = curl_open,
 503     .bdrv_close      = curl_close,
 504     .bdrv_getlength  = curl_getlength,
 505
 506     .bdrv_aio_readv  = curl_aio_readv,
 507 };
 508
 509 static void curl_block_init(void)
 510 {
 511     bdrv_register(&bdrv_http);
 512     bdrv_register(&bdrv_https);
 513     bdrv_register(&bdrv_ftp);
 514     bdrv_register(&bdrv_ftps);
 515     bdrv_register(&bdrv_tftp);
 516 }
 517
 518 block_init(curl_block_init);