http.c

   1 #include "http.h"
   2
   3 int data_received;
   4 int active_requests;
   5
   6 #ifdef USE_CURL_MULTI
   7 static int max_requests = -1;
   8 static CURLM *curlm;
   9 #endif
  10 #ifndef NO_CURL_EASY_DUPHANDLE
  11 static CURL *curl_default;
  12 #endif
  13 char curl_errorstr[CURL_ERROR_SIZE];
  14
  15 static int curl_ssl_verify = -1;
  16 static const char *ssl_cert;
  17 #if LIBCURL_VERSION_NUM >= 0x070902
  18 static const char *ssl_key;
  19 #endif
  20 #if LIBCURL_VERSION_NUM >= 0x070908
  21 static const char *ssl_capath;
  22 #endif
  23 static const char *ssl_cainfo;
  24 static long curl_low_speed_limit = -1;
  25 static long curl_low_speed_time = -1;
  26 static int curl_ftp_no_epsv;
  27 static const char *curl_http_proxy;
  28 static char *user_name, *user_pass;
  29
  30 #if LIBCURL_VERSION_NUM >= 0x071700
  31 /* Use CURLOPT_KEYPASSWD as is */
  32 #elif LIBCURL_VERSION_NUM >= 0x070903
  33 #define CURLOPT_KEYPASSWD CURLOPT_SSLKEYPASSWD
  34 #else
  35 #define CURLOPT_KEYPASSWD CURLOPT_SSLCERTPASSWD
  36 #endif
  37
  38 static char *ssl_cert_password;
  39 static int ssl_cert_password_required;
  40
  41 static struct curl_slist *pragma_header;
  42
  43 static struct active_request_slot *active_queue_head;
  44
  45 size_t fread_buffer(void *ptr, size_t eltsize, size_t nmemb, void *buffer_)
  46 {
  47         size_t size = eltsize * nmemb;
  48         struct buffer *buffer = buffer_;
  49
  50         if (size > buffer->buf.len - buffer->posn)
  51                 size = buffer->buf.len - buffer->posn;
  52         memcpy(ptr, buffer->buf.buf + buffer->posn, size);
  53         buffer->posn += size;
  54
  55         return size;
  56 }
  57
  58 #ifndef NO_CURL_IOCTL
  59 curlioerr ioctl_buffer(CURL *handle, int cmd, void *clientp)
  60 {
  61         struct buffer *buffer = clientp;
  62
  63         switch (cmd) {
  64         case CURLIOCMD_NOP:
  65                 return CURLIOE_OK;
  66
  67         case CURLIOCMD_RESTARTREAD:
  68                 buffer->posn = 0;
  69                 return CURLIOE_OK;
  70
  71         default:
  72                 return CURLIOE_UNKNOWNCMD;
  73         }
  74 }
  75 #endif
  76
  77 size_t fwrite_buffer(const void *ptr, size_t eltsize, size_t nmemb, void *buffer_)
  78 {
  79         size_t size = eltsize * nmemb;
  80         struct strbuf *buffer = buffer_;
  81
  82         strbuf_add(buffer, ptr, size);
  83         data_received++;
  84         return size;
  85 }
  86
  87 size_t fwrite_null(const void *ptr, size_t eltsize, size_t nmemb, void *strbuf)
  88 {
  89         data_received++;
  90         return eltsize * nmemb;
  91 }
  92
  93 static void finish_active_slot(struct active_request_slot *slot);
  94
  95 #ifdef USE_CURL_MULTI
  96 static void process_curl_messages(void)
  97 {
  98         int num_messages;
  99         struct active_request_slot *slot;
 100         CURLMsg *curl_message = curl_multi_info_read(curlm, &num_messages);
 101
 102         while (curl_message != NULL) {
 103                 if (curl_message->msg == CURLMSG_DONE) {
 104                         int curl_result = curl_message->data.result;
 105                         slot = active_queue_head;
 106                         while (slot != NULL &&
 107                                slot->curl != curl_message->easy_handle)
 108                                 slot = slot->next;
 109                         if (slot != NULL) {
 110                                 curl_multi_remove_handle(curlm, slot->curl);
 111                                 slot->curl_result = curl_result;
 112                                 finish_active_slot(slot);
 113                         } else {
 114                                 fprintf(stderr, "Received DONE message for unknown request!\n");
 115                         }
 116                 } else {
 117                         fprintf(stderr, "Unknown CURL message received: %d\n",
 118                                 (int)curl_message->msg);
 119                 }
 120                 curl_message = curl_multi_info_read(curlm, &num_messages);
 121         }
 122 }
 123 #endif
 124
 125 static int http_options(const char *var, const char *value, void *cb)
 126 {
 127         if (!strcmp("http.sslverify", var)) {
 128                 curl_ssl_verify = git_config_bool(var, value);
 129                 return 0;
 130         }
 131         if (!strcmp("http.sslcert", var))
 132                 return git_config_string(&ssl_cert, var, value);
 133 #if LIBCURL_VERSION_NUM >= 0x070902
 134         if (!strcmp("http.sslkey", var))
 135                 return git_config_string(&ssl_key, var, value);
 136 #endif
 137 #if LIBCURL_VERSION_NUM >= 0x070908
 138         if (!strcmp("http.sslcapath", var))
 139                 return git_config_string(&ssl_capath, var, value);
 140 #endif
 141         if (!strcmp("http.sslcainfo", var))
 142                 return git_config_string(&ssl_cainfo, var, value);
 143         if (!strcmp("http.sslcertpasswordprotected", var)) {
 144                 if (git_config_bool(var, value))
 145                         ssl_cert_password_required = 1;
 146                 return 0;
 147         }
 148 #ifdef USE_CURL_MULTI
 149         if (!strcmp("http.maxrequests", var)) {
 150                 max_requests = git_config_int(var, value);
 151                 return 0;
 152         }
 153 #endif
 154         if (!strcmp("http.lowspeedlimit", var)) {
 155                 curl_low_speed_limit = (long)git_config_int(var, value);
 156                 return 0;
 157         }
 158         if (!strcmp("http.lowspeedtime", var)) {
 159                 curl_low_speed_time = (long)git_config_int(var, value);
 160                 return 0;
 161         }
 162
 163         if (!strcmp("http.noepsv", var)) {
 164                 curl_ftp_no_epsv = git_config_bool(var, value);
 165                 return 0;
 166         }
 167         if (!strcmp("http.proxy", var))
 168                 return git_config_string(&curl_http_proxy, var, value);
 169
 170         /* Fall back on the default ones */
 171         return git_default_config(var, value, cb);
 172 }
 173
 174 static void init_curl_http_auth(CURL *result)
 175 {
 176         if (user_name) {
 177                 struct strbuf up = STRBUF_INIT;
 178                 if (!user_pass)
 179                         user_pass = xstrdup(getpass("Password: "));
 180                 strbuf_addf(&up, "%s:%s", user_name, user_pass);
 181                 curl_easy_setopt(result, CURLOPT_USERPWD,
 182                                  strbuf_detach(&up, NULL));
 183         }
 184 }
 185
 186 static int has_cert_password(void)
 187 {
 188         if (ssl_cert_password != NULL)
 189                 return 1;
 190         if (ssl_cert == NULL || ssl_cert_password_required != 1)
 191                 return 0;
 192         /* Only prompt the user once. */
 193         ssl_cert_password_required = -1;
 194         ssl_cert_password = getpass("Certificate Password: ");
 195         if (ssl_cert_password != NULL) {
 196                 ssl_cert_password = xstrdup(ssl_cert_password);
 197                 return 1;
 198         } else
 199                 return 0;
 200 }
 201
 202 static CURL *get_curl_handle(void)
 203 {
 204         CURL *result = curl_easy_init();
 205
 206         if (!curl_ssl_verify) {
 207                 curl_easy_setopt(result, CURLOPT_SSL_VERIFYPEER, 0);
 208                 curl_easy_setopt(result, CURLOPT_SSL_VERIFYHOST, 0);
 209         } else {
 210                 /* Verify authenticity of the peer's certificate */
 211                 curl_easy_setopt(result, CURLOPT_SSL_VERIFYPEER, 1);
 212                 /* The name in the cert must match whom we tried to connect */
 213                 curl_easy_setopt(result, CURLOPT_SSL_VERIFYHOST, 2);
 214         }
 215
 216 #if LIBCURL_VERSION_NUM >= 0x070907
 217         curl_easy_setopt(result, CURLOPT_NETRC, CURL_NETRC_OPTIONAL);
 218 #endif
 219
 220         init_curl_http_auth(result);
 221
 222         if (ssl_cert != NULL)
 223                 curl_easy_setopt(result, CURLOPT_SSLCERT, ssl_cert);
 224         if (has_cert_password())
 225                 curl_easy_setopt(result, CURLOPT_KEYPASSWD, ssl_cert_password);
 226 #if LIBCURL_VERSION_NUM >= 0x070902
 227         if (ssl_key != NULL)
 228                 curl_easy_setopt(result, CURLOPT_SSLKEY, ssl_key);
 229 #endif
 230 #if LIBCURL_VERSION_NUM >= 0x070908
 231         if (ssl_capath != NULL)
 232                 curl_easy_setopt(result, CURLOPT_CAPATH, ssl_capath);
 233 #endif
 234         if (ssl_cainfo != NULL)
 235                 curl_easy_setopt(result, CURLOPT_CAINFO, ssl_cainfo);
 236         curl_easy_setopt(result, CURLOPT_FAILONERROR, 1);
 237
 238         if (curl_low_speed_limit > 0 && curl_low_speed_time > 0) {
 239                 curl_easy_setopt(result, CURLOPT_LOW_SPEED_LIMIT,
 240                                  curl_low_speed_limit);
 241                 curl_easy_setopt(result, CURLOPT_LOW_SPEED_TIME,
 242                                  curl_low_speed_time);
 243         }
 244
 245         curl_easy_setopt(result, CURLOPT_FOLLOWLOCATION, 1);
 246
 247         if (getenv("GIT_CURL_VERBOSE"))
 248                 curl_easy_setopt(result, CURLOPT_VERBOSE, 1);
 249
 250         curl_easy_setopt(result, CURLOPT_USERAGENT, GIT_USER_AGENT);
 251
 252         if (curl_ftp_no_epsv)
 253                 curl_easy_setopt(result, CURLOPT_FTP_USE_EPSV, 0);
 254
 255         if (curl_http_proxy)
 256                 curl_easy_setopt(result, CURLOPT_PROXY, curl_http_proxy);
 257
 258         return result;
 259 }
 260
 261 static void http_auth_init(const char *url)
 262 {
 263         char *at, *colon, *cp, *slash;
 264         int len;
 265
 266         cp = strstr(url, "://");
 267         if (!cp)
 268                 return;
 269
 270         /*
 271          * Ok, the URL looks like "proto://something".  Which one?
 272          * "proto://<user>:<pass>@<host>/...",
 273          * "proto://<user>@<host>/...", or just
 274          * "proto://<host>/..."?
 275          */
 276         cp += 3;
 277         at = strchr(cp, '@');
 278         colon = strchr(cp, ':');
 279         slash = strchrnul(cp, '/');
 280         if (!at || slash <= at)
 281                 return; /* No credentials */
 282         if (!colon || at <= colon) {
 283                 /* Only username */
 284                 len = at - cp;
 285                 user_name = xmalloc(len + 1);
 286                 memcpy(user_name, cp, len);
 287                 user_name[len] = '\0';
 288                 user_pass = NULL;
 289         } else {
 290                 len = colon - cp;
 291                 user_name = xmalloc(len + 1);
 292                 memcpy(user_name, cp, len);
 293                 user_name[len] = '\0';
 294                 len = at - (colon + 1);
 295                 user_pass = xmalloc(len + 1);
 296                 memcpy(user_pass, colon + 1, len);
 297                 user_pass[len] = '\0';
 298         }
 299 }
 300
 301 static void set_from_env(const char **var, const char *envname)
 302 {
 303         const char *val = getenv(envname);
 304         if (val)
 305                 *var = val;
 306 }
 307
 308 void http_init(struct remote *remote)
 309 {
 310         char *low_speed_limit;
 311         char *low_speed_time;
 312
 313         git_config(http_options, NULL);
 314
 315         curl_global_init(CURL_GLOBAL_ALL);
 316
 317         if (remote && remote->http_proxy)
 318                 curl_http_proxy = xstrdup(remote->http_proxy);
 319
 320         pragma_header = curl_slist_append(pragma_header, "Pragma: no-cache");
 321
 322 #ifdef USE_CURL_MULTI
 323         {
 324                 char *http_max_requests = getenv("GIT_HTTP_MAX_REQUESTS");
 325                 if (http_max_requests != NULL)
 326                         max_requests = atoi(http_max_requests);
 327         }
 328
 329         curlm = curl_multi_init();
 330         if (curlm == NULL) {
 331                 fprintf(stderr, "Error creating curl multi handle.\n");
 332                 exit(1);
 333         }
 334 #endif
 335
 336         if (getenv("GIT_SSL_NO_VERIFY"))
 337                 curl_ssl_verify = 0;
 338
 339         set_from_env(&ssl_cert, "GIT_SSL_CERT");
 340 #if LIBCURL_VERSION_NUM >= 0x070902
 341         set_from_env(&ssl_key, "GIT_SSL_KEY");
 342 #endif
 343 #if LIBCURL_VERSION_NUM >= 0x070908
 344         set_from_env(&ssl_capath, "GIT_SSL_CAPATH");
 345 #endif
 346         set_from_env(&ssl_cainfo, "GIT_SSL_CAINFO");
 347
 348         low_speed_limit = getenv("GIT_HTTP_LOW_SPEED_LIMIT");
 349         if (low_speed_limit != NULL)
 350                 curl_low_speed_limit = strtol(low_speed_limit, NULL, 10);
 351         low_speed_time = getenv("GIT_HTTP_LOW_SPEED_TIME");
 352         if (low_speed_time != NULL)
 353                 curl_low_speed_time = strtol(low_speed_time, NULL, 10);
 354
 355         if (curl_ssl_verify == -1)
 356                 curl_ssl_verify = 1;
 357
 358 #ifdef USE_CURL_MULTI
 359         if (max_requests < 1)
 360                 max_requests = DEFAULT_MAX_REQUESTS;
 361 #endif
 362
 363         if (getenv("GIT_CURL_FTP_NO_EPSV"))
 364                 curl_ftp_no_epsv = 1;
 365
 366         if (remote && remote->url && remote->url[0]) {
 367                 http_auth_init(remote->url[0]);
 368                 if (!ssl_cert_password_required &&
 369                     getenv("GIT_SSL_CERT_PASSWORD_PROTECTED") &&
 370                     !prefixcmp(remote->url[0], "https://"))
 371                         ssl_cert_password_required = 1;
 372         }
 373
 374 #ifndef NO_CURL_EASY_DUPHANDLE
 375         curl_default = get_curl_handle();
 376 #endif
 377 }
 378
 379 void http_cleanup(void)
 380 {
 381         struct active_request_slot *slot = active_queue_head;
 382
 383         while (slot != NULL) {
 384                 struct active_request_slot *next = slot->next;
 385                 if (slot->curl != NULL) {
 386 #ifdef USE_CURL_MULTI
 387                         curl_multi_remove_handle(curlm, slot->curl);
 388 #endif
 389                         curl_easy_cleanup(slot->curl);
 390                 }
 391                 free(slot);
 392                 slot = next;
 393         }
 394         active_queue_head = NULL;
 395
 396 #ifndef NO_CURL_EASY_DUPHANDLE
 397         curl_easy_cleanup(curl_default);
 398 #endif
 399
 400 #ifdef USE_CURL_MULTI
 401         curl_multi_cleanup(curlm);
 402 #endif
 403         curl_global_cleanup();
 404
 405         curl_slist_free_all(pragma_header);
 406         pragma_header = NULL;
 407
 408         if (curl_http_proxy) {
 409                 free((void *)curl_http_proxy);
 410                 curl_http_proxy = NULL;
 411         }
 412
 413         if (ssl_cert_password != NULL) {
 414                 memset(ssl_cert_password, 0, strlen(ssl_cert_password));
 415                 free(ssl_cert_password);
 416                 ssl_cert_password = NULL;
 417         }
 418         ssl_cert_password_required = 0;
 419 }
 420
 421 struct active_request_slot *get_active_slot(void)
 422 {
 423         struct active_request_slot *slot = active_queue_head;
 424         struct active_request_slot *newslot;
 425
 426 #ifdef USE_CURL_MULTI
 427         int num_transfers;
 428
 429         /* Wait for a slot to open up if the queue is full */
 430         while (active_requests >= max_requests) {
 431                 curl_multi_perform(curlm, &num_transfers);
 432                 if (num_transfers < active_requests)
 433                         process_curl_messages();
 434         }
 435 #endif
 436
 437         while (slot != NULL && slot->in_use)
 438                 slot = slot->next;
 439
 440         if (slot == NULL) {
 441                 newslot = xmalloc(sizeof(*newslot));
 442                 newslot->curl = NULL;
 443                 newslot->in_use = 0;
 444                 newslot->next = NULL;
 445
 446                 slot = active_queue_head;
 447                 if (slot == NULL) {
 448                         active_queue_head = newslot;
 449                 } else {
 450                         while (slot->next != NULL)
 451                                 slot = slot->next;
 452                         slot->next = newslot;
 453                 }
 454                 slot = newslot;
 455         }
 456
 457         if (slot->curl == NULL) {
 458 #ifdef NO_CURL_EASY_DUPHANDLE
 459                 slot->curl = get_curl_handle();
 460 #else
 461                 slot->curl = curl_easy_duphandle(curl_default);
 462 #endif
 463         }
 464
 465         active_requests++;
 466         slot->in_use = 1;
 467         slot->local = NULL;
 468         slot->results = NULL;
 469         slot->finished = NULL;
 470         slot->callback_data = NULL;
 471         slot->callback_func = NULL;
 472         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, pragma_header);
 473         curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, curl_errorstr);
 474         curl_easy_setopt(slot->curl, CURLOPT_CUSTOMREQUEST, NULL);
 475         curl_easy_setopt(slot->curl, CURLOPT_READFUNCTION, NULL);
 476         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, NULL);
 477         curl_easy_setopt(slot->curl, CURLOPT_UPLOAD, 0);
 478         curl_easy_setopt(slot->curl, CURLOPT_HTTPGET, 1);
 479
 480         return slot;
 481 }
 482
 483 int start_active_slot(struct active_request_slot *slot)
 484 {
 485 #ifdef USE_CURL_MULTI
 486         CURLMcode curlm_result = curl_multi_add_handle(curlm, slot->curl);
 487         int num_transfers;
 488
 489         if (curlm_result != CURLM_OK &&
 490             curlm_result != CURLM_CALL_MULTI_PERFORM) {
 491                 active_requests--;
 492                 slot->in_use = 0;
 493                 return 0;
 494         }
 495
 496         /*
 497          * We know there must be something to do, since we just added
 498          * something.
 499          */
 500         curl_multi_perform(curlm, &num_transfers);
 501 #endif
 502         return 1;
 503 }
 504
 505 #ifdef USE_CURL_MULTI
 506 struct fill_chain {
 507         void *data;
 508         int (*fill)(void *);
 509         struct fill_chain *next;
 510 };
 511
 512 static struct fill_chain *fill_cfg;
 513
 514 void add_fill_function(void *data, int (*fill)(void *))
 515 {
 516         struct fill_chain *new = xmalloc(sizeof(*new));
 517         struct fill_chain **linkp = &fill_cfg;
 518         new->data = data;
 519         new->fill = fill;
 520         new->next = NULL;
 521         while (*linkp)
 522                 linkp = &(*linkp)->next;
 523         *linkp = new;
 524 }
 525
 526 void fill_active_slots(void)
 527 {
 528         struct active_request_slot *slot = active_queue_head;
 529
 530         while (active_requests < max_requests) {
 531                 struct fill_chain *fill;
 532                 for (fill = fill_cfg; fill; fill = fill->next)
 533                         if (fill->fill(fill->data))
 534                                 break;
 535
 536                 if (!fill)
 537                         break;
 538         }
 539
 540         while (slot != NULL) {
 541                 if (!slot->in_use && slot->curl != NULL) {
 542                         curl_easy_cleanup(slot->curl);
 543                         slot->curl = NULL;
 544                 }
 545                 slot = slot->next;
 546         }
 547 }
 548
 549 void step_active_slots(void)
 550 {
 551         int num_transfers;
 552         CURLMcode curlm_result;
 553
 554         do {
 555                 curlm_result = curl_multi_perform(curlm, &num_transfers);
 556         } while (curlm_result == CURLM_CALL_MULTI_PERFORM);
 557         if (num_transfers < active_requests) {
 558                 process_curl_messages();
 559                 fill_active_slots();
 560         }
 561 }
 562 #endif
 563
 564 void run_active_slot(struct active_request_slot *slot)
 565 {
 566 #ifdef USE_CURL_MULTI
 567         long last_pos = 0;
 568         long current_pos;
 569         fd_set readfds;
 570         fd_set writefds;
 571         fd_set excfds;
 572         int max_fd;
 573         struct timeval select_timeout;
 574         int finished = 0;
 575
 576         slot->finished = &finished;
 577         while (!finished) {
 578                 data_received = 0;
 579                 step_active_slots();
 580
 581                 if (!data_received && slot->local != NULL) {
 582                         current_pos = ftell(slot->local);
 583                         if (current_pos > last_pos)
 584                                 data_received++;
 585                         last_pos = current_pos;
 586                 }
 587
 588                 if (slot->in_use && !data_received) {
 589                         max_fd = 0;
 590                         FD_ZERO(&readfds);
 591                         FD_ZERO(&writefds);
 592                         FD_ZERO(&excfds);
 593                         select_timeout.tv_sec = 0;
 594                         select_timeout.tv_usec = 50000;
 595                         select(max_fd, &readfds, &writefds,
 596                                &excfds, &select_timeout);
 597                 }
 598         }
 599 #else
 600         while (slot->in_use) {
 601                 slot->curl_result = curl_easy_perform(slot->curl);
 602                 finish_active_slot(slot);
 603         }
 604 #endif
 605 }
 606
 607 static void closedown_active_slot(struct active_request_slot *slot)
 608 {
 609         active_requests--;
 610         slot->in_use = 0;
 611 }
 612
 613 void release_active_slot(struct active_request_slot *slot)
 614 {
 615         closedown_active_slot(slot);
 616         if (slot->curl) {
 617 #ifdef USE_CURL_MULTI
 618                 curl_multi_remove_handle(curlm, slot->curl);
 619 #endif
 620                 curl_easy_cleanup(slot->curl);
 621                 slot->curl = NULL;
 622         }
 623 #ifdef USE_CURL_MULTI
 624         fill_active_slots();
 625 #endif
 626 }
 627
 628 static void finish_active_slot(struct active_request_slot *slot)
 629 {
 630         closedown_active_slot(slot);
 631         curl_easy_getinfo(slot->curl, CURLINFO_HTTP_CODE, &slot->http_code);
 632
 633         if (slot->finished != NULL)
 634                 (*slot->finished) = 1;
 635
 636         /* Store slot results so they can be read after the slot is reused */
 637         if (slot->results != NULL) {
 638                 slot->results->curl_result = slot->curl_result;
 639                 slot->results->http_code = slot->http_code;
 640         }
 641
 642         /* Run callback if appropriate */
 643         if (slot->callback_func != NULL)
 644                 slot->callback_func(slot->callback_data);
 645 }
 646
 647 void finish_all_active_slots(void)
 648 {
 649         struct active_request_slot *slot = active_queue_head;
 650
 651         while (slot != NULL)
 652                 if (slot->in_use) {
 653                         run_active_slot(slot);
 654                         slot = active_queue_head;
 655                 } else {
 656                         slot = slot->next;
 657                 }
 658 }
 659
 660 static inline int needs_quote(int ch)
 661 {
 662         if (((ch >= 'A') && (ch <= 'Z'))
 663                         || ((ch >= 'a') && (ch <= 'z'))
 664                         || ((ch >= '0') && (ch <= '9'))
 665                         || (ch == '/')
 666                         || (ch == '-')
 667                         || (ch == '.'))
 668                 return 0;
 669         return 1;
 670 }
 671
 672 static inline int hex(int v)
 673 {
 674         if (v < 10)
 675                 return '0' + v;
 676         else
 677                 return 'A' + v - 10;
 678 }
 679
 680 static char *quote_ref_url(const char *base, const char *ref)
 681 {
 682         struct strbuf buf = STRBUF_INIT;
 683         const char *cp;
 684         int ch;
 685
 686         strbuf_addstr(&buf, base);
 687         if (buf.len && buf.buf[buf.len - 1] != '/' && *ref != '/')
 688                 strbuf_addstr(&buf, "/");
 689
 690         for (cp = ref; (ch = *cp) != 0; cp++)
 691                 if (needs_quote(ch))
 692                         strbuf_addf(&buf, "%%%02x", ch);
 693                 else
 694                         strbuf_addch(&buf, *cp);
 695
 696         return strbuf_detach(&buf, NULL);
 697 }
 698
 699 int http_fetch_ref(const char *base, struct ref *ref)
 700 {
 701         char *url;
 702         struct strbuf buffer = STRBUF_INIT;
 703         struct active_request_slot *slot;
 704         struct slot_results results;
 705         int ret;
 706
 707         url = quote_ref_url(base, ref->name);
 708         slot = get_active_slot();
 709         slot->results = &results;
 710         curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 711         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 712         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 713         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 714         if (start_active_slot(slot)) {
 715                 run_active_slot(slot);
 716                 if (results.curl_result == CURLE_OK) {
 717                         strbuf_rtrim(&buffer);
 718                         if (buffer.len == 40)
 719                                 ret = get_sha1_hex(buffer.buf, ref->old_sha1);
 720                         else if (!prefixcmp(buffer.buf, "ref: ")) {
 721                                 ref->symref = xstrdup(buffer.buf + 5);
 722                                 ret = 0;
 723                         } else
 724                                 ret = 1;
 725                 } else {
 726                         ret = error("Couldn't get %s for %s\n%s",
 727                                     url, ref->name, curl_errorstr);
 728                 }
 729         } else {
 730                 ret = error("Unable to start request");
 731         }
 732
 733         strbuf_release(&buffer);
 734         free(url);
 735         return ret;
 736 }