http.c

   1 #include "http.h"
   2
   3 int data_received;
   4 int active_requests;
   5 int http_is_verbose;
   6
   7 #ifdef USE_CURL_MULTI
   8 static int max_requests = -1;
   9 static CURLM *curlm;
  10 #endif
  11 #ifndef NO_CURL_EASY_DUPHANDLE
  12 static CURL *curl_default;
  13 #endif
  14 char curl_errorstr[CURL_ERROR_SIZE];
  15
  16 static int curl_ssl_verify = -1;
  17 static const char *ssl_cert;
  18 #if LIBCURL_VERSION_NUM >= 0x070902
  19 static const char *ssl_key;
  20 #endif
  21 #if LIBCURL_VERSION_NUM >= 0x070908
  22 static const char *ssl_capath;
  23 #endif
  24 static const char *ssl_cainfo;
  25 static long curl_low_speed_limit = -1;
  26 static long curl_low_speed_time = -1;
  27 static int curl_ftp_no_epsv;
  28 static const char *curl_http_proxy;
  29 static char *user_name, *user_pass;
  30
  31 static struct curl_slist *pragma_header;
  32
  33 struct curl_slist *no_pragma_header;
  34
  35 static struct active_request_slot *active_queue_head;
  36
  37 size_t fread_buffer(void *ptr, size_t eltsize, size_t nmemb, void *buffer_)
  38 {
  39         size_t size = eltsize * nmemb;
  40         struct buffer *buffer = buffer_;
  41
  42         if (size > buffer->buf.len - buffer->posn)
  43                 size = buffer->buf.len - buffer->posn;
  44         memcpy(ptr, buffer->buf.buf + buffer->posn, size);
  45         buffer->posn += size;
  46
  47         return size;
  48 }
  49
  50 #ifndef NO_CURL_IOCTL
  51 curlioerr ioctl_buffer(CURL *handle, int cmd, void *clientp)
  52 {
  53         struct buffer *buffer = clientp;
  54
  55         switch (cmd) {
  56         case CURLIOCMD_NOP:
  57                 return CURLIOE_OK;
  58
  59         case CURLIOCMD_RESTARTREAD:
  60                 buffer->posn = 0;
  61                 return CURLIOE_OK;
  62
  63         default:
  64                 return CURLIOE_UNKNOWNCMD;
  65         }
  66 }
  67 #endif
  68
  69 size_t fwrite_buffer(const void *ptr, size_t eltsize, size_t nmemb, void *buffer_)
  70 {
  71         size_t size = eltsize * nmemb;
  72         struct strbuf *buffer = buffer_;
  73
  74         strbuf_add(buffer, ptr, size);
  75         data_received++;
  76         return size;
  77 }
  78
  79 size_t fwrite_null(const void *ptr, size_t eltsize, size_t nmemb, void *strbuf)
  80 {
  81         data_received++;
  82         return eltsize * nmemb;
  83 }
  84
  85 static void finish_active_slot(struct active_request_slot *slot);
  86
  87 #ifdef USE_CURL_MULTI
  88 static void process_curl_messages(void)
  89 {
  90         int num_messages;
  91         struct active_request_slot *slot;
  92         CURLMsg *curl_message = curl_multi_info_read(curlm, &num_messages);
  93
  94         while (curl_message != NULL) {
  95                 if (curl_message->msg == CURLMSG_DONE) {
  96                         int curl_result = curl_message->data.result;
  97                         slot = active_queue_head;
  98                         while (slot != NULL &&
  99                                slot->curl != curl_message->easy_handle)
 100                                 slot = slot->next;
 101                         if (slot != NULL) {
 102                                 curl_multi_remove_handle(curlm, slot->curl);
 103                                 slot->curl_result = curl_result;
 104                                 finish_active_slot(slot);
 105                         } else {
 106                                 fprintf(stderr, "Received DONE message for unknown request!\n");
 107                         }
 108                 } else {
 109                         fprintf(stderr, "Unknown CURL message received: %d\n",
 110                                 (int)curl_message->msg);
 111                 }
 112                 curl_message = curl_multi_info_read(curlm, &num_messages);
 113         }
 114 }
 115 #endif
 116
 117 static int http_options(const char *var, const char *value, void *cb)
 118 {
 119         if (!strcmp("http.sslverify", var)) {
 120                 curl_ssl_verify = git_config_bool(var, value);
 121                 return 0;
 122         }
 123         if (!strcmp("http.sslcert", var))
 124                 return git_config_string(&ssl_cert, var, value);
 125 #if LIBCURL_VERSION_NUM >= 0x070902
 126         if (!strcmp("http.sslkey", var))
 127                 return git_config_string(&ssl_key, var, value);
 128 #endif
 129 #if LIBCURL_VERSION_NUM >= 0x070908
 130         if (!strcmp("http.sslcapath", var))
 131                 return git_config_string(&ssl_capath, var, value);
 132 #endif
 133         if (!strcmp("http.sslcainfo", var))
 134                 return git_config_string(&ssl_cainfo, var, value);
 135 #ifdef USE_CURL_MULTI
 136         if (!strcmp("http.maxrequests", var)) {
 137                 max_requests = git_config_int(var, value);
 138                 return 0;
 139         }
 140 #endif
 141         if (!strcmp("http.lowspeedlimit", var)) {
 142                 curl_low_speed_limit = (long)git_config_int(var, value);
 143                 return 0;
 144         }
 145         if (!strcmp("http.lowspeedtime", var)) {
 146                 curl_low_speed_time = (long)git_config_int(var, value);
 147                 return 0;
 148         }
 149
 150         if (!strcmp("http.noepsv", var)) {
 151                 curl_ftp_no_epsv = git_config_bool(var, value);
 152                 return 0;
 153         }
 154         if (!strcmp("http.proxy", var))
 155                 return git_config_string(&curl_http_proxy, var, value);
 156
 157         /* Fall back on the default ones */
 158         return git_default_config(var, value, cb);
 159 }
 160
 161 static void init_curl_http_auth(CURL *result)
 162 {
 163         if (user_name) {
 164                 struct strbuf up = STRBUF_INIT;
 165                 if (!user_pass)
 166                         user_pass = xstrdup(getpass("Password: "));
 167                 strbuf_addf(&up, "%s:%s", user_name, user_pass);
 168                 curl_easy_setopt(result, CURLOPT_USERPWD,
 169                                  strbuf_detach(&up, NULL));
 170         }
 171 }
 172
 173 static CURL *get_curl_handle(void)
 174 {
 175         CURL *result = curl_easy_init();
 176
 177         if (!curl_ssl_verify) {
 178                 curl_easy_setopt(result, CURLOPT_SSL_VERIFYPEER, 0);
 179                 curl_easy_setopt(result, CURLOPT_SSL_VERIFYHOST, 0);
 180         } else {
 181                 /* Verify authenticity of the peer's certificate */
 182                 curl_easy_setopt(result, CURLOPT_SSL_VERIFYPEER, 1);
 183                 /* The name in the cert must match whom we tried to connect */
 184                 curl_easy_setopt(result, CURLOPT_SSL_VERIFYHOST, 2);
 185         }
 186
 187 #if LIBCURL_VERSION_NUM >= 0x070907
 188         curl_easy_setopt(result, CURLOPT_NETRC, CURL_NETRC_OPTIONAL);
 189 #endif
 190
 191         init_curl_http_auth(result);
 192
 193         if (ssl_cert != NULL)
 194                 curl_easy_setopt(result, CURLOPT_SSLCERT, ssl_cert);
 195 #if LIBCURL_VERSION_NUM >= 0x070902
 196         if (ssl_key != NULL)
 197                 curl_easy_setopt(result, CURLOPT_SSLKEY, ssl_key);
 198 #endif
 199 #if LIBCURL_VERSION_NUM >= 0x070908
 200         if (ssl_capath != NULL)
 201                 curl_easy_setopt(result, CURLOPT_CAPATH, ssl_capath);
 202 #endif
 203         if (ssl_cainfo != NULL)
 204                 curl_easy_setopt(result, CURLOPT_CAINFO, ssl_cainfo);
 205         curl_easy_setopt(result, CURLOPT_FAILONERROR, 1);
 206
 207         if (curl_low_speed_limit > 0 && curl_low_speed_time > 0) {
 208                 curl_easy_setopt(result, CURLOPT_LOW_SPEED_LIMIT,
 209                                  curl_low_speed_limit);
 210                 curl_easy_setopt(result, CURLOPT_LOW_SPEED_TIME,
 211                                  curl_low_speed_time);
 212         }
 213
 214         curl_easy_setopt(result, CURLOPT_FOLLOWLOCATION, 1);
 215
 216         if (getenv("GIT_CURL_VERBOSE"))
 217                 curl_easy_setopt(result, CURLOPT_VERBOSE, 1);
 218
 219         curl_easy_setopt(result, CURLOPT_USERAGENT, GIT_USER_AGENT);
 220
 221         if (curl_ftp_no_epsv)
 222                 curl_easy_setopt(result, CURLOPT_FTP_USE_EPSV, 0);
 223
 224         if (curl_http_proxy)
 225                 curl_easy_setopt(result, CURLOPT_PROXY, curl_http_proxy);
 226
 227         return result;
 228 }
 229
 230 static void http_auth_init(const char *url)
 231 {
 232         char *at, *colon, *cp, *slash;
 233         int len;
 234
 235         cp = strstr(url, "://");
 236         if (!cp)
 237                 return;
 238
 239         /*
 240          * Ok, the URL looks like "proto://something".  Which one?
 241          * "proto://<user>:<pass>@<host>/...",
 242          * "proto://<user>@<host>/...", or just
 243          * "proto://<host>/..."?
 244          */
 245         cp += 3;
 246         at = strchr(cp, '@');
 247         colon = strchr(cp, ':');
 248         slash = strchrnul(cp, '/');
 249         if (!at || slash <= at)
 250                 return; /* No credentials */
 251         if (!colon || at <= colon) {
 252                 /* Only username */
 253                 len = at - cp;
 254                 user_name = xmalloc(len + 1);
 255                 memcpy(user_name, cp, len);
 256                 user_name[len] = '\0';
 257                 user_pass = NULL;
 258         } else {
 259                 len = colon - cp;
 260                 user_name = xmalloc(len + 1);
 261                 memcpy(user_name, cp, len);
 262                 user_name[len] = '\0';
 263                 len = at - (colon + 1);
 264                 user_pass = xmalloc(len + 1);
 265                 memcpy(user_pass, colon + 1, len);
 266                 user_pass[len] = '\0';
 267         }
 268 }
 269
 270 static void set_from_env(const char **var, const char *envname)
 271 {
 272         const char *val = getenv(envname);
 273         if (val)
 274                 *var = val;
 275 }
 276
 277 void http_init(struct remote *remote)
 278 {
 279         char *low_speed_limit;
 280         char *low_speed_time;
 281
 282         http_is_verbose = 0;
 283
 284         git_config(http_options, NULL);
 285
 286         curl_global_init(CURL_GLOBAL_ALL);
 287
 288         if (remote && remote->http_proxy)
 289                 curl_http_proxy = xstrdup(remote->http_proxy);
 290
 291         pragma_header = curl_slist_append(pragma_header, "Pragma: no-cache");
 292         no_pragma_header = curl_slist_append(no_pragma_header, "Pragma:");
 293
 294 #ifdef USE_CURL_MULTI
 295         {
 296                 char *http_max_requests = getenv("GIT_HTTP_MAX_REQUESTS");
 297                 if (http_max_requests != NULL)
 298                         max_requests = atoi(http_max_requests);
 299         }
 300
 301         curlm = curl_multi_init();
 302         if (curlm == NULL) {
 303                 fprintf(stderr, "Error creating curl multi handle.\n");
 304                 exit(1);
 305         }
 306 #endif
 307
 308         if (getenv("GIT_SSL_NO_VERIFY"))
 309                 curl_ssl_verify = 0;
 310
 311         set_from_env(&ssl_cert, "GIT_SSL_CERT");
 312 #if LIBCURL_VERSION_NUM >= 0x070902
 313         set_from_env(&ssl_key, "GIT_SSL_KEY");
 314 #endif
 315 #if LIBCURL_VERSION_NUM >= 0x070908
 316         set_from_env(&ssl_capath, "GIT_SSL_CAPATH");
 317 #endif
 318         set_from_env(&ssl_cainfo, "GIT_SSL_CAINFO");
 319
 320         low_speed_limit = getenv("GIT_HTTP_LOW_SPEED_LIMIT");
 321         if (low_speed_limit != NULL)
 322                 curl_low_speed_limit = strtol(low_speed_limit, NULL, 10);
 323         low_speed_time = getenv("GIT_HTTP_LOW_SPEED_TIME");
 324         if (low_speed_time != NULL)
 325                 curl_low_speed_time = strtol(low_speed_time, NULL, 10);
 326
 327         if (curl_ssl_verify == -1)
 328                 curl_ssl_verify = 1;
 329
 330 #ifdef USE_CURL_MULTI
 331         if (max_requests < 1)
 332                 max_requests = DEFAULT_MAX_REQUESTS;
 333 #endif
 334
 335         if (getenv("GIT_CURL_FTP_NO_EPSV"))
 336                 curl_ftp_no_epsv = 1;
 337
 338         if (remote && remote->url && remote->url[0])
 339                 http_auth_init(remote->url[0]);
 340
 341 #ifndef NO_CURL_EASY_DUPHANDLE
 342         curl_default = get_curl_handle();
 343 #endif
 344 }
 345
 346 void http_cleanup(void)
 347 {
 348         struct active_request_slot *slot = active_queue_head;
 349
 350         while (slot != NULL) {
 351                 struct active_request_slot *next = slot->next;
 352                 if (slot->curl != NULL) {
 353 #ifdef USE_CURL_MULTI
 354                         curl_multi_remove_handle(curlm, slot->curl);
 355 #endif
 356                         curl_easy_cleanup(slot->curl);
 357                 }
 358                 free(slot);
 359                 slot = next;
 360         }
 361         active_queue_head = NULL;
 362
 363 #ifndef NO_CURL_EASY_DUPHANDLE
 364         curl_easy_cleanup(curl_default);
 365 #endif
 366
 367 #ifdef USE_CURL_MULTI
 368         curl_multi_cleanup(curlm);
 369 #endif
 370         curl_global_cleanup();
 371
 372         curl_slist_free_all(pragma_header);
 373         pragma_header = NULL;
 374
 375         curl_slist_free_all(no_pragma_header);
 376         no_pragma_header = NULL;
 377
 378         if (curl_http_proxy) {
 379                 free((void *)curl_http_proxy);
 380                 curl_http_proxy = NULL;
 381         }
 382 }
 383
 384 struct active_request_slot *get_active_slot(void)
 385 {
 386         struct active_request_slot *slot = active_queue_head;
 387         struct active_request_slot *newslot;
 388
 389 #ifdef USE_CURL_MULTI
 390         int num_transfers;
 391
 392         /* Wait for a slot to open up if the queue is full */
 393         while (active_requests >= max_requests) {
 394                 curl_multi_perform(curlm, &num_transfers);
 395                 if (num_transfers < active_requests)
 396                         process_curl_messages();
 397         }
 398 #endif
 399
 400         while (slot != NULL && slot->in_use)
 401                 slot = slot->next;
 402
 403         if (slot == NULL) {
 404                 newslot = xmalloc(sizeof(*newslot));
 405                 newslot->curl = NULL;
 406                 newslot->in_use = 0;
 407                 newslot->next = NULL;
 408
 409                 slot = active_queue_head;
 410                 if (slot == NULL) {
 411                         active_queue_head = newslot;
 412                 } else {
 413                         while (slot->next != NULL)
 414                                 slot = slot->next;
 415                         slot->next = newslot;
 416                 }
 417                 slot = newslot;
 418         }
 419
 420         if (slot->curl == NULL) {
 421 #ifdef NO_CURL_EASY_DUPHANDLE
 422                 slot->curl = get_curl_handle();
 423 #else
 424                 slot->curl = curl_easy_duphandle(curl_default);
 425 #endif
 426         }
 427
 428         active_requests++;
 429         slot->in_use = 1;
 430         slot->local = NULL;
 431         slot->results = NULL;
 432         slot->finished = NULL;
 433         slot->callback_data = NULL;
 434         slot->callback_func = NULL;
 435         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, pragma_header);
 436         curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, curl_errorstr);
 437         curl_easy_setopt(slot->curl, CURLOPT_CUSTOMREQUEST, NULL);
 438         curl_easy_setopt(slot->curl, CURLOPT_READFUNCTION, NULL);
 439         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, NULL);
 440         curl_easy_setopt(slot->curl, CURLOPT_UPLOAD, 0);
 441         curl_easy_setopt(slot->curl, CURLOPT_HTTPGET, 1);
 442
 443         return slot;
 444 }
 445
 446 int start_active_slot(struct active_request_slot *slot)
 447 {
 448 #ifdef USE_CURL_MULTI
 449         CURLMcode curlm_result = curl_multi_add_handle(curlm, slot->curl);
 450         int num_transfers;
 451
 452         if (curlm_result != CURLM_OK &&
 453             curlm_result != CURLM_CALL_MULTI_PERFORM) {
 454                 active_requests--;
 455                 slot->in_use = 0;
 456                 return 0;
 457         }
 458
 459         /*
 460          * We know there must be something to do, since we just added
 461          * something.
 462          */
 463         curl_multi_perform(curlm, &num_transfers);
 464 #endif
 465         return 1;
 466 }
 467
 468 #ifdef USE_CURL_MULTI
 469 struct fill_chain {
 470         void *data;
 471         int (*fill)(void *);
 472         struct fill_chain *next;
 473 };
 474
 475 static struct fill_chain *fill_cfg;
 476
 477 void add_fill_function(void *data, int (*fill)(void *))
 478 {
 479         struct fill_chain *new = xmalloc(sizeof(*new));
 480         struct fill_chain **linkp = &fill_cfg;
 481         new->data = data;
 482         new->fill = fill;
 483         new->next = NULL;
 484         while (*linkp)
 485                 linkp = &(*linkp)->next;
 486         *linkp = new;
 487 }
 488
 489 void fill_active_slots(void)
 490 {
 491         struct active_request_slot *slot = active_queue_head;
 492
 493         while (active_requests < max_requests) {
 494                 struct fill_chain *fill;
 495                 for (fill = fill_cfg; fill; fill = fill->next)
 496                         if (fill->fill(fill->data))
 497                                 break;
 498
 499                 if (!fill)
 500                         break;
 501         }
 502
 503         while (slot != NULL) {
 504                 if (!slot->in_use && slot->curl != NULL) {
 505                         curl_easy_cleanup(slot->curl);
 506                         slot->curl = NULL;
 507                 }
 508                 slot = slot->next;
 509         }
 510 }
 511
 512 void step_active_slots(void)
 513 {
 514         int num_transfers;
 515         CURLMcode curlm_result;
 516
 517         do {
 518                 curlm_result = curl_multi_perform(curlm, &num_transfers);
 519         } while (curlm_result == CURLM_CALL_MULTI_PERFORM);
 520         if (num_transfers < active_requests) {
 521                 process_curl_messages();
 522                 fill_active_slots();
 523         }
 524 }
 525 #endif
 526
 527 void run_active_slot(struct active_request_slot *slot)
 528 {
 529 #ifdef USE_CURL_MULTI
 530         long last_pos = 0;
 531         long current_pos;
 532         fd_set readfds;
 533         fd_set writefds;
 534         fd_set excfds;
 535         int max_fd;
 536         struct timeval select_timeout;
 537         int finished = 0;
 538
 539         slot->finished = &finished;
 540         while (!finished) {
 541                 data_received = 0;
 542                 step_active_slots();
 543
 544                 if (!data_received && slot->local != NULL) {
 545                         current_pos = ftell(slot->local);
 546                         if (current_pos > last_pos)
 547                                 data_received++;
 548                         last_pos = current_pos;
 549                 }
 550
 551                 if (slot->in_use && !data_received) {
 552                         max_fd = 0;
 553                         FD_ZERO(&readfds);
 554                         FD_ZERO(&writefds);
 555                         FD_ZERO(&excfds);
 556                         select_timeout.tv_sec = 0;
 557                         select_timeout.tv_usec = 50000;
 558                         select(max_fd, &readfds, &writefds,
 559                                &excfds, &select_timeout);
 560                 }
 561         }
 562 #else
 563         while (slot->in_use) {
 564                 slot->curl_result = curl_easy_perform(slot->curl);
 565                 finish_active_slot(slot);
 566         }
 567 #endif
 568 }
 569
 570 static void closedown_active_slot(struct active_request_slot *slot)
 571 {
 572         active_requests--;
 573         slot->in_use = 0;
 574 }
 575
 576 void release_active_slot(struct active_request_slot *slot)
 577 {
 578         closedown_active_slot(slot);
 579         if (slot->curl) {
 580 #ifdef USE_CURL_MULTI
 581                 curl_multi_remove_handle(curlm, slot->curl);
 582 #endif
 583                 curl_easy_cleanup(slot->curl);
 584                 slot->curl = NULL;
 585         }
 586 #ifdef USE_CURL_MULTI
 587         fill_active_slots();
 588 #endif
 589 }
 590
 591 static void finish_active_slot(struct active_request_slot *slot)
 592 {
 593         closedown_active_slot(slot);
 594         curl_easy_getinfo(slot->curl, CURLINFO_HTTP_CODE, &slot->http_code);
 595
 596         if (slot->finished != NULL)
 597                 (*slot->finished) = 1;
 598
 599         /* Store slot results so they can be read after the slot is reused */
 600         if (slot->results != NULL) {
 601                 slot->results->curl_result = slot->curl_result;
 602                 slot->results->http_code = slot->http_code;
 603         }
 604
 605         /* Run callback if appropriate */
 606         if (slot->callback_func != NULL)
 607                 slot->callback_func(slot->callback_data);
 608 }
 609
 610 void finish_all_active_slots(void)
 611 {
 612         struct active_request_slot *slot = active_queue_head;
 613
 614         while (slot != NULL)
 615                 if (slot->in_use) {
 616                         run_active_slot(slot);
 617                         slot = active_queue_head;
 618                 } else {
 619                         slot = slot->next;
 620                 }
 621 }
 622
 623 /* Helpers for modifying and creating URLs */
 624 static inline int needs_quote(int ch)
 625 {
 626         if (((ch >= 'A') && (ch <= 'Z'))
 627                         || ((ch >= 'a') && (ch <= 'z'))
 628                         || ((ch >= '0') && (ch <= '9'))
 629                         || (ch == '/')
 630                         || (ch == '-')
 631                         || (ch == '.'))
 632                 return 0;
 633         return 1;
 634 }
 635
 636 static inline int hex(int v)
 637 {
 638         if (v < 10)
 639                 return '0' + v;
 640         else
 641                 return 'A' + v - 10;
 642 }
 643
 644 static void end_url_with_slash(struct strbuf *buf, const char *url)
 645 {
 646         strbuf_addstr(buf, url);
 647         if (buf->len && buf->buf[buf->len - 1] != '/')
 648                 strbuf_addstr(buf, "/");
 649 }
 650
 651 static char *quote_ref_url(const char *base, const char *ref)
 652 {
 653         struct strbuf buf = STRBUF_INIT;
 654         const char *cp;
 655         int ch;
 656
 657         end_url_with_slash(&buf, base);
 658
 659         for (cp = ref; (ch = *cp) != 0; cp++)
 660                 if (needs_quote(ch))
 661                         strbuf_addf(&buf, "%%%02x", ch);
 662                 else
 663                         strbuf_addch(&buf, *cp);
 664
 665         return strbuf_detach(&buf, NULL);
 666 }
 667
 668 /* http_request() targets */
 669 #define HTTP_REQUEST_STRBUF     0
 670 #define HTTP_REQUEST_FILE       1
 671
 672 static int http_request(const char *url, void *result, int target, int options)
 673 {
 674         struct active_request_slot *slot;
 675         struct slot_results results;
 676         struct curl_slist *headers = NULL;
 677         struct strbuf buf = STRBUF_INIT;
 678         int ret;
 679
 680         slot = get_active_slot();
 681         slot->results = &results;
 682         curl_easy_setopt(slot->curl, CURLOPT_HTTPGET, 1);
 683
 684         if (result == NULL) {
 685                 curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 1);
 686         } else {
 687                 curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 0);
 688                 curl_easy_setopt(slot->curl, CURLOPT_FILE, result);
 689
 690                 if (target == HTTP_REQUEST_FILE) {
 691                         long posn = ftell(result);
 692                         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
 693                                          fwrite);
 694                         if (posn > 0) {
 695                                 strbuf_addf(&buf, "Range: bytes=%ld-", posn);
 696                                 headers = curl_slist_append(headers, buf.buf);
 697                                 strbuf_reset(&buf);
 698                         }
 699                         slot->local = result;
 700                 } else
 701                         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
 702                                          fwrite_buffer);
 703         }
 704
 705         strbuf_addstr(&buf, "Pragma:");
 706         if (options & HTTP_NO_CACHE)
 707                 strbuf_addstr(&buf, " no-cache");
 708
 709         headers = curl_slist_append(headers, buf.buf);
 710
 711         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 712         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, headers);
 713
 714         if (start_active_slot(slot)) {
 715                 run_active_slot(slot);
 716                 if (results.curl_result == CURLE_OK)
 717                         ret = HTTP_OK;
 718                 else if (missing_target(&results))
 719                         ret = HTTP_MISSING_TARGET;
 720                 else
 721                         ret = HTTP_ERROR;
 722         } else {
 723                 error("Unable to start HTTP request for %s", url);
 724                 ret = HTTP_START_FAILED;
 725         }
 726
 727         slot->local = NULL;
 728         curl_slist_free_all(headers);
 729         strbuf_release(&buf);
 730
 731         return ret;
 732 }
 733
 734 int http_get_strbuf(const char *url, struct strbuf *result, int options)
 735 {
 736         return http_request(url, result, HTTP_REQUEST_STRBUF, options);
 737 }
 738
 739 int http_get_file(const char *url, const char *filename, int options)
 740 {
 741         int ret;
 742         struct strbuf tmpfile = STRBUF_INIT;
 743         FILE *result;
 744
 745         strbuf_addf(&tmpfile, "%s.temp", filename);
 746         result = fopen(tmpfile.buf, "a");
 747         if (! result) {
 748                 error("Unable to open local file %s", tmpfile.buf);
 749                 ret = HTTP_ERROR;
 750                 goto cleanup;
 751         }
 752
 753         ret = http_request(url, result, HTTP_REQUEST_FILE, options);
 754         fclose(result);
 755
 756         if ((ret == HTTP_OK) && move_temp_to_file(tmpfile.buf, filename))
 757                 ret = HTTP_ERROR;
 758 cleanup:
 759         strbuf_release(&tmpfile);
 760         return ret;
 761 }
 762
 763 int http_error(const char *url, int ret)
 764 {
 765         /* http_request has already handled HTTP_START_FAILED. */
 766         if (ret != HTTP_START_FAILED)
 767                 error("%s while accessing %s\n", curl_errorstr, url);
 768
 769         return ret;
 770 }
 771
 772 int http_fetch_ref(const char *base, struct ref *ref)
 773 {
 774         char *url;
 775         struct strbuf buffer = STRBUF_INIT;
 776         int ret = -1;
 777
 778         url = quote_ref_url(base, ref->name);
 779         if (http_get_strbuf(url, &buffer, HTTP_NO_CACHE) == HTTP_OK) {
 780                 strbuf_rtrim(&buffer);
 781                 if (buffer.len == 40)
 782                         ret = get_sha1_hex(buffer.buf, ref->old_sha1);
 783                 else if (!prefixcmp(buffer.buf, "ref: ")) {
 784                         ref->symref = xstrdup(buffer.buf + 5);
 785                         ret = 0;
 786                 }
 787         }
 788
 789         strbuf_release(&buffer);
 790         free(url);
 791         return ret;
 792 }