http.c

   1 #include "http.h"
   2 #include "pack.h"
   3 #include "sideband.h"
   4 #include "run-command.h"
   5 #include "url.h"
   6 #include "credential.h"
   7 #include "version.h"
   8 #include "pkt-line.h"
   9
  10 int active_requests;
  11 int http_is_verbose;
  12 size_t http_post_buffer = 16 * LARGE_PACKET_MAX;
  13
  14 #if LIBCURL_VERSION_NUM >= 0x070a06
  15 #define LIBCURL_CAN_HANDLE_AUTH_ANY
  16 #endif
  17
  18 static int min_curl_sessions = 1;
  19 static int curl_session_count;
  20 #ifdef USE_CURL_MULTI
  21 static int max_requests = -1;
  22 static CURLM *curlm;
  23 #endif
  24 #ifndef NO_CURL_EASY_DUPHANDLE
  25 static CURL *curl_default;
  26 #endif
  27
  28 #define PREV_BUF_SIZE 4096
  29 #define RANGE_HEADER_SIZE 30
  30
  31 char curl_errorstr[CURL_ERROR_SIZE];
  32
  33 static int curl_ssl_verify = -1;
  34 static int curl_ssl_try;
  35 static const char *ssl_cert;
  36 #if LIBCURL_VERSION_NUM >= 0x070903
  37 static const char *ssl_key;
  38 #endif
  39 #if LIBCURL_VERSION_NUM >= 0x070908
  40 static const char *ssl_capath;
  41 #endif
  42 static const char *ssl_cainfo;
  43 static long curl_low_speed_limit = -1;
  44 static long curl_low_speed_time = -1;
  45 static int curl_ftp_no_epsv;
  46 static const char *curl_http_proxy;
  47 static const char *curl_cookie_file;
  48 static struct credential http_auth = CREDENTIAL_INIT;
  49 static int http_proactive_auth;
  50 static const char *user_agent;
  51
  52 #if LIBCURL_VERSION_NUM >= 0x071700
  53 /* Use CURLOPT_KEYPASSWD as is */
  54 #elif LIBCURL_VERSION_NUM >= 0x070903
  55 #define CURLOPT_KEYPASSWD CURLOPT_SSLKEYPASSWD
  56 #else
  57 #define CURLOPT_KEYPASSWD CURLOPT_SSLCERTPASSWD
  58 #endif
  59
  60 static struct credential cert_auth = CREDENTIAL_INIT;
  61 static int ssl_cert_password_required;
  62
  63 static struct curl_slist *pragma_header;
  64 static struct curl_slist *no_pragma_header;
  65
  66 static struct active_request_slot *active_queue_head;
  67
  68 size_t fread_buffer(char *ptr, size_t eltsize, size_t nmemb, void *buffer_)
  69 {
  70         size_t size = eltsize * nmemb;
  71         struct buffer *buffer = buffer_;
  72
  73         if (size > buffer->buf.len - buffer->posn)
  74                 size = buffer->buf.len - buffer->posn;
  75         memcpy(ptr, buffer->buf.buf + buffer->posn, size);
  76         buffer->posn += size;
  77
  78         return size;
  79 }
  80
  81 #ifndef NO_CURL_IOCTL
  82 curlioerr ioctl_buffer(CURL *handle, int cmd, void *clientp)
  83 {
  84         struct buffer *buffer = clientp;
  85
  86         switch (cmd) {
  87         case CURLIOCMD_NOP:
  88                 return CURLIOE_OK;
  89
  90         case CURLIOCMD_RESTARTREAD:
  91                 buffer->posn = 0;
  92                 return CURLIOE_OK;
  93
  94         default:
  95                 return CURLIOE_UNKNOWNCMD;
  96         }
  97 }
  98 #endif
  99
 100 size_t fwrite_buffer(char *ptr, size_t eltsize, size_t nmemb, void *buffer_)
 101 {
 102         size_t size = eltsize * nmemb;
 103         struct strbuf *buffer = buffer_;
 104
 105         strbuf_add(buffer, ptr, size);
 106         return size;
 107 }
 108
 109 size_t fwrite_null(char *ptr, size_t eltsize, size_t nmemb, void *strbuf)
 110 {
 111         return eltsize * nmemb;
 112 }
 113
 114 #ifdef USE_CURL_MULTI
 115 static void process_curl_messages(void)
 116 {
 117         int num_messages;
 118         struct active_request_slot *slot;
 119         CURLMsg *curl_message = curl_multi_info_read(curlm, &num_messages);
 120
 121         while (curl_message != NULL) {
 122                 if (curl_message->msg == CURLMSG_DONE) {
 123                         int curl_result = curl_message->data.result;
 124                         slot = active_queue_head;
 125                         while (slot != NULL &&
 126                                slot->curl != curl_message->easy_handle)
 127                                 slot = slot->next;
 128                         if (slot != NULL) {
 129                                 curl_multi_remove_handle(curlm, slot->curl);
 130                                 slot->curl_result = curl_result;
 131                                 finish_active_slot(slot);
 132                         } else {
 133                                 fprintf(stderr, "Received DONE message for unknown request!\n");
 134                         }
 135                 } else {
 136                         fprintf(stderr, "Unknown CURL message received: %d\n",
 137                                 (int)curl_message->msg);
 138                 }
 139                 curl_message = curl_multi_info_read(curlm, &num_messages);
 140         }
 141 }
 142 #endif
 143
 144 static int http_options(const char *var, const char *value, void *cb)
 145 {
 146         if (!strcmp("http.sslverify", var)) {
 147                 curl_ssl_verify = git_config_bool(var, value);
 148                 return 0;
 149         }
 150         if (!strcmp("http.sslcert", var))
 151                 return git_config_string(&ssl_cert, var, value);
 152 #if LIBCURL_VERSION_NUM >= 0x070903
 153         if (!strcmp("http.sslkey", var))
 154                 return git_config_string(&ssl_key, var, value);
 155 #endif
 156 #if LIBCURL_VERSION_NUM >= 0x070908
 157         if (!strcmp("http.sslcapath", var))
 158                 return git_config_string(&ssl_capath, var, value);
 159 #endif
 160         if (!strcmp("http.sslcainfo", var))
 161                 return git_config_string(&ssl_cainfo, var, value);
 162         if (!strcmp("http.sslcertpasswordprotected", var)) {
 163                 if (git_config_bool(var, value))
 164                         ssl_cert_password_required = 1;
 165                 return 0;
 166         }
 167         if (!strcmp("http.ssltry", var)) {
 168                 curl_ssl_try = git_config_bool(var, value);
 169                 return 0;
 170         }
 171         if (!strcmp("http.minsessions", var)) {
 172                 min_curl_sessions = git_config_int(var, value);
 173 #ifndef USE_CURL_MULTI
 174                 if (min_curl_sessions > 1)
 175                         min_curl_sessions = 1;
 176 #endif
 177                 return 0;
 178         }
 179 #ifdef USE_CURL_MULTI
 180         if (!strcmp("http.maxrequests", var)) {
 181                 max_requests = git_config_int(var, value);
 182                 return 0;
 183         }
 184 #endif
 185         if (!strcmp("http.lowspeedlimit", var)) {
 186                 curl_low_speed_limit = (long)git_config_int(var, value);
 187                 return 0;
 188         }
 189         if (!strcmp("http.lowspeedtime", var)) {
 190                 curl_low_speed_time = (long)git_config_int(var, value);
 191                 return 0;
 192         }
 193
 194         if (!strcmp("http.noepsv", var)) {
 195                 curl_ftp_no_epsv = git_config_bool(var, value);
 196                 return 0;
 197         }
 198         if (!strcmp("http.proxy", var))
 199                 return git_config_string(&curl_http_proxy, var, value);
 200
 201         if (!strcmp("http.cookiefile", var))
 202                 return git_config_string(&curl_cookie_file, var, value);
 203
 204         if (!strcmp("http.postbuffer", var)) {
 205                 http_post_buffer = git_config_int(var, value);
 206                 if (http_post_buffer < LARGE_PACKET_MAX)
 207                         http_post_buffer = LARGE_PACKET_MAX;
 208                 return 0;
 209         }
 210
 211         if (!strcmp("http.useragent", var))
 212                 return git_config_string(&user_agent, var, value);
 213
 214         /* Fall back on the default ones */
 215         return git_default_config(var, value, cb);
 216 }
 217
 218 static void init_curl_http_auth(CURL *result)
 219 {
 220         if (!http_auth.username)
 221                 return;
 222
 223         credential_fill(&http_auth);
 224
 225 #if LIBCURL_VERSION_NUM >= 0x071301
 226         curl_easy_setopt(result, CURLOPT_USERNAME, http_auth.username);
 227         curl_easy_setopt(result, CURLOPT_PASSWORD, http_auth.password);
 228 #else
 229         {
 230                 static struct strbuf up = STRBUF_INIT;
 231                 /*
 232                  * Note that we assume we only ever have a single set of
 233                  * credentials in a given program run, so we do not have
 234                  * to worry about updating this buffer, only setting its
 235                  * initial value.
 236                  */
 237                 if (!up.len)
 238                         strbuf_addf(&up, "%s:%s",
 239                                 http_auth.username, http_auth.password);
 240                 curl_easy_setopt(result, CURLOPT_USERPWD, up.buf);
 241         }
 242 #endif
 243 }
 244
 245 static int has_cert_password(void)
 246 {
 247         if (ssl_cert == NULL || ssl_cert_password_required != 1)
 248                 return 0;
 249         if (!cert_auth.password) {
 250                 cert_auth.protocol = xstrdup("cert");
 251                 cert_auth.username = xstrdup("");
 252                 cert_auth.path = xstrdup(ssl_cert);
 253                 credential_fill(&cert_auth);
 254         }
 255         return 1;
 256 }
 257
 258 static CURL *get_curl_handle(void)
 259 {
 260         CURL *result = curl_easy_init();
 261
 262         if (!curl_ssl_verify) {
 263                 curl_easy_setopt(result, CURLOPT_SSL_VERIFYPEER, 0);
 264                 curl_easy_setopt(result, CURLOPT_SSL_VERIFYHOST, 0);
 265         } else {
 266                 /* Verify authenticity of the peer's certificate */
 267                 curl_easy_setopt(result, CURLOPT_SSL_VERIFYPEER, 1);
 268                 /* The name in the cert must match whom we tried to connect */
 269                 curl_easy_setopt(result, CURLOPT_SSL_VERIFYHOST, 2);
 270         }
 271
 272 #if LIBCURL_VERSION_NUM >= 0x070907
 273         curl_easy_setopt(result, CURLOPT_NETRC, CURL_NETRC_OPTIONAL);
 274 #endif
 275 #ifdef LIBCURL_CAN_HANDLE_AUTH_ANY
 276         curl_easy_setopt(result, CURLOPT_HTTPAUTH, CURLAUTH_ANY);
 277 #endif
 278
 279         if (http_proactive_auth)
 280                 init_curl_http_auth(result);
 281
 282         if (ssl_cert != NULL)
 283                 curl_easy_setopt(result, CURLOPT_SSLCERT, ssl_cert);
 284         if (has_cert_password())
 285                 curl_easy_setopt(result, CURLOPT_KEYPASSWD, cert_auth.password);
 286 #if LIBCURL_VERSION_NUM >= 0x070903
 287         if (ssl_key != NULL)
 288                 curl_easy_setopt(result, CURLOPT_SSLKEY, ssl_key);
 289 #endif
 290 #if LIBCURL_VERSION_NUM >= 0x070908
 291         if (ssl_capath != NULL)
 292                 curl_easy_setopt(result, CURLOPT_CAPATH, ssl_capath);
 293 #endif
 294         if (ssl_cainfo != NULL)
 295                 curl_easy_setopt(result, CURLOPT_CAINFO, ssl_cainfo);
 296
 297         if (curl_low_speed_limit > 0 && curl_low_speed_time > 0) {
 298                 curl_easy_setopt(result, CURLOPT_LOW_SPEED_LIMIT,
 299                                  curl_low_speed_limit);
 300                 curl_easy_setopt(result, CURLOPT_LOW_SPEED_TIME,
 301                                  curl_low_speed_time);
 302         }
 303
 304         curl_easy_setopt(result, CURLOPT_FOLLOWLOCATION, 1);
 305 #if LIBCURL_VERSION_NUM >= 0x071301
 306         curl_easy_setopt(result, CURLOPT_POSTREDIR, CURL_REDIR_POST_ALL);
 307 #elif LIBCURL_VERSION_NUM >= 0x071101
 308         curl_easy_setopt(result, CURLOPT_POST301, 1);
 309 #endif
 310
 311         if (getenv("GIT_CURL_VERBOSE"))
 312                 curl_easy_setopt(result, CURLOPT_VERBOSE, 1);
 313
 314         curl_easy_setopt(result, CURLOPT_USERAGENT,
 315                 user_agent ? user_agent : git_user_agent());
 316
 317         if (curl_ftp_no_epsv)
 318                 curl_easy_setopt(result, CURLOPT_FTP_USE_EPSV, 0);
 319
 320 #ifdef CURLOPT_USE_SSL
 321         if (curl_ssl_try)
 322                 curl_easy_setopt(result, CURLOPT_USE_SSL, CURLUSESSL_TRY);
 323 #endif
 324
 325         if (curl_http_proxy) {
 326                 curl_easy_setopt(result, CURLOPT_PROXY, curl_http_proxy);
 327                 curl_easy_setopt(result, CURLOPT_PROXYAUTH, CURLAUTH_ANY);
 328         }
 329
 330         return result;
 331 }
 332
 333 static void set_from_env(const char **var, const char *envname)
 334 {
 335         const char *val = getenv(envname);
 336         if (val)
 337                 *var = val;
 338 }
 339
 340 void http_init(struct remote *remote, const char *url, int proactive_auth)
 341 {
 342         char *low_speed_limit;
 343         char *low_speed_time;
 344
 345         http_is_verbose = 0;
 346
 347         git_config(http_options, NULL);
 348
 349         curl_global_init(CURL_GLOBAL_ALL);
 350
 351         http_proactive_auth = proactive_auth;
 352
 353         if (remote && remote->http_proxy)
 354                 curl_http_proxy = xstrdup(remote->http_proxy);
 355
 356         pragma_header = curl_slist_append(pragma_header, "Pragma: no-cache");
 357         no_pragma_header = curl_slist_append(no_pragma_header, "Pragma:");
 358
 359 #ifdef USE_CURL_MULTI
 360         {
 361                 char *http_max_requests = getenv("GIT_HTTP_MAX_REQUESTS");
 362                 if (http_max_requests != NULL)
 363                         max_requests = atoi(http_max_requests);
 364         }
 365
 366         curlm = curl_multi_init();
 367         if (curlm == NULL) {
 368                 fprintf(stderr, "Error creating curl multi handle.\n");
 369                 exit(1);
 370         }
 371 #endif
 372
 373         if (getenv("GIT_SSL_NO_VERIFY"))
 374                 curl_ssl_verify = 0;
 375
 376         set_from_env(&ssl_cert, "GIT_SSL_CERT");
 377 #if LIBCURL_VERSION_NUM >= 0x070903
 378         set_from_env(&ssl_key, "GIT_SSL_KEY");
 379 #endif
 380 #if LIBCURL_VERSION_NUM >= 0x070908
 381         set_from_env(&ssl_capath, "GIT_SSL_CAPATH");
 382 #endif
 383         set_from_env(&ssl_cainfo, "GIT_SSL_CAINFO");
 384
 385         set_from_env(&user_agent, "GIT_HTTP_USER_AGENT");
 386
 387         low_speed_limit = getenv("GIT_HTTP_LOW_SPEED_LIMIT");
 388         if (low_speed_limit != NULL)
 389                 curl_low_speed_limit = strtol(low_speed_limit, NULL, 10);
 390         low_speed_time = getenv("GIT_HTTP_LOW_SPEED_TIME");
 391         if (low_speed_time != NULL)
 392                 curl_low_speed_time = strtol(low_speed_time, NULL, 10);
 393
 394         if (curl_ssl_verify == -1)
 395                 curl_ssl_verify = 1;
 396
 397         curl_session_count = 0;
 398 #ifdef USE_CURL_MULTI
 399         if (max_requests < 1)
 400                 max_requests = DEFAULT_MAX_REQUESTS;
 401 #endif
 402
 403         if (getenv("GIT_CURL_FTP_NO_EPSV"))
 404                 curl_ftp_no_epsv = 1;
 405
 406         if (url) {
 407                 credential_from_url(&http_auth, url);
 408                 if (!ssl_cert_password_required &&
 409                     getenv("GIT_SSL_CERT_PASSWORD_PROTECTED") &&
 410                     !prefixcmp(url, "https://"))
 411                         ssl_cert_password_required = 1;
 412         }
 413
 414 #ifndef NO_CURL_EASY_DUPHANDLE
 415         curl_default = get_curl_handle();
 416 #endif
 417 }
 418
 419 void http_cleanup(void)
 420 {
 421         struct active_request_slot *slot = active_queue_head;
 422
 423         while (slot != NULL) {
 424                 struct active_request_slot *next = slot->next;
 425                 if (slot->curl != NULL) {
 426 #ifdef USE_CURL_MULTI
 427                         curl_multi_remove_handle(curlm, slot->curl);
 428 #endif
 429                         curl_easy_cleanup(slot->curl);
 430                 }
 431                 free(slot);
 432                 slot = next;
 433         }
 434         active_queue_head = NULL;
 435
 436 #ifndef NO_CURL_EASY_DUPHANDLE
 437         curl_easy_cleanup(curl_default);
 438 #endif
 439
 440 #ifdef USE_CURL_MULTI
 441         curl_multi_cleanup(curlm);
 442 #endif
 443         curl_global_cleanup();
 444
 445         curl_slist_free_all(pragma_header);
 446         pragma_header = NULL;
 447
 448         curl_slist_free_all(no_pragma_header);
 449         no_pragma_header = NULL;
 450
 451         if (curl_http_proxy) {
 452                 free((void *)curl_http_proxy);
 453                 curl_http_proxy = NULL;
 454         }
 455
 456         if (cert_auth.password != NULL) {
 457                 memset(cert_auth.password, 0, strlen(cert_auth.password));
 458                 free(cert_auth.password);
 459                 cert_auth.password = NULL;
 460         }
 461         ssl_cert_password_required = 0;
 462 }
 463
 464 struct active_request_slot *get_active_slot(void)
 465 {
 466         struct active_request_slot *slot = active_queue_head;
 467         struct active_request_slot *newslot;
 468
 469 #ifdef USE_CURL_MULTI
 470         int num_transfers;
 471
 472         /* Wait for a slot to open up if the queue is full */
 473         while (active_requests >= max_requests) {
 474                 curl_multi_perform(curlm, &num_transfers);
 475                 if (num_transfers < active_requests)
 476                         process_curl_messages();
 477         }
 478 #endif
 479
 480         while (slot != NULL && slot->in_use)
 481                 slot = slot->next;
 482
 483         if (slot == NULL) {
 484                 newslot = xmalloc(sizeof(*newslot));
 485                 newslot->curl = NULL;
 486                 newslot->in_use = 0;
 487                 newslot->next = NULL;
 488
 489                 slot = active_queue_head;
 490                 if (slot == NULL) {
 491                         active_queue_head = newslot;
 492                 } else {
 493                         while (slot->next != NULL)
 494                                 slot = slot->next;
 495                         slot->next = newslot;
 496                 }
 497                 slot = newslot;
 498         }
 499
 500         if (slot->curl == NULL) {
 501 #ifdef NO_CURL_EASY_DUPHANDLE
 502                 slot->curl = get_curl_handle();
 503 #else
 504                 slot->curl = curl_easy_duphandle(curl_default);
 505 #endif
 506                 curl_session_count++;
 507         }
 508
 509         active_requests++;
 510         slot->in_use = 1;
 511         slot->results = NULL;
 512         slot->finished = NULL;
 513         slot->callback_data = NULL;
 514         slot->callback_func = NULL;
 515         curl_easy_setopt(slot->curl, CURLOPT_COOKIEFILE, curl_cookie_file);
 516         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, pragma_header);
 517         curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, curl_errorstr);
 518         curl_easy_setopt(slot->curl, CURLOPT_CUSTOMREQUEST, NULL);
 519         curl_easy_setopt(slot->curl, CURLOPT_READFUNCTION, NULL);
 520         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, NULL);
 521         curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDS, NULL);
 522         curl_easy_setopt(slot->curl, CURLOPT_UPLOAD, 0);
 523         curl_easy_setopt(slot->curl, CURLOPT_HTTPGET, 1);
 524         curl_easy_setopt(slot->curl, CURLOPT_FAILONERROR, 1);
 525         if (http_auth.password)
 526                 init_curl_http_auth(slot->curl);
 527
 528         return slot;
 529 }
 530
 531 int start_active_slot(struct active_request_slot *slot)
 532 {
 533 #ifdef USE_CURL_MULTI
 534         CURLMcode curlm_result = curl_multi_add_handle(curlm, slot->curl);
 535         int num_transfers;
 536
 537         if (curlm_result != CURLM_OK &&
 538             curlm_result != CURLM_CALL_MULTI_PERFORM) {
 539                 active_requests--;
 540                 slot->in_use = 0;
 541                 return 0;
 542         }
 543
 544         /*
 545          * We know there must be something to do, since we just added
 546          * something.
 547          */
 548         curl_multi_perform(curlm, &num_transfers);
 549 #endif
 550         return 1;
 551 }
 552
 553 #ifdef USE_CURL_MULTI
 554 struct fill_chain {
 555         void *data;
 556         int (*fill)(void *);
 557         struct fill_chain *next;
 558 };
 559
 560 static struct fill_chain *fill_cfg;
 561
 562 void add_fill_function(void *data, int (*fill)(void *))
 563 {
 564         struct fill_chain *new = xmalloc(sizeof(*new));
 565         struct fill_chain **linkp = &fill_cfg;
 566         new->data = data;
 567         new->fill = fill;
 568         new->next = NULL;
 569         while (*linkp)
 570                 linkp = &(*linkp)->next;
 571         *linkp = new;
 572 }
 573
 574 void fill_active_slots(void)
 575 {
 576         struct active_request_slot *slot = active_queue_head;
 577
 578         while (active_requests < max_requests) {
 579                 struct fill_chain *fill;
 580                 for (fill = fill_cfg; fill; fill = fill->next)
 581                         if (fill->fill(fill->data))
 582                                 break;
 583
 584                 if (!fill)
 585                         break;
 586         }
 587
 588         while (slot != NULL) {
 589                 if (!slot->in_use && slot->curl != NULL
 590                         && curl_session_count > min_curl_sessions) {
 591                         curl_easy_cleanup(slot->curl);
 592                         slot->curl = NULL;
 593                         curl_session_count--;
 594                 }
 595                 slot = slot->next;
 596         }
 597 }
 598
 599 void step_active_slots(void)
 600 {
 601         int num_transfers;
 602         CURLMcode curlm_result;
 603
 604         do {
 605                 curlm_result = curl_multi_perform(curlm, &num_transfers);
 606         } while (curlm_result == CURLM_CALL_MULTI_PERFORM);
 607         if (num_transfers < active_requests) {
 608                 process_curl_messages();
 609                 fill_active_slots();
 610         }
 611 }
 612 #endif
 613
 614 void run_active_slot(struct active_request_slot *slot)
 615 {
 616 #ifdef USE_CURL_MULTI
 617         fd_set readfds;
 618         fd_set writefds;
 619         fd_set excfds;
 620         int max_fd;
 621         struct timeval select_timeout;
 622         int finished = 0;
 623
 624         slot->finished = &finished;
 625         while (!finished) {
 626                 step_active_slots();
 627
 628                 if (slot->in_use) {
 629 #if LIBCURL_VERSION_NUM >= 0x070f04
 630                         long curl_timeout;
 631                         curl_multi_timeout(curlm, &curl_timeout);
 632                         if (curl_timeout == 0) {
 633                                 continue;
 634                         } else if (curl_timeout == -1) {
 635                                 select_timeout.tv_sec  = 0;
 636                                 select_timeout.tv_usec = 50000;
 637                         } else {
 638                                 select_timeout.tv_sec  =  curl_timeout / 1000;
 639                                 select_timeout.tv_usec = (curl_timeout % 1000) * 1000;
 640                         }
 641 #else
 642                         select_timeout.tv_sec  = 0;
 643                         select_timeout.tv_usec = 50000;
 644 #endif
 645
 646                         max_fd = -1;
 647                         FD_ZERO(&readfds);
 648                         FD_ZERO(&writefds);
 649                         FD_ZERO(&excfds);
 650                         curl_multi_fdset(curlm, &readfds, &writefds, &excfds, &max_fd);
 651
 652                         /*
 653                          * It can happen that curl_multi_timeout returns a pathologically
 654                          * long timeout when curl_multi_fdset returns no file descriptors
 655                          * to read.  See commit message for more details.
 656                          */
 657                         if (max_fd < 0 &&
 658                             (select_timeout.tv_sec > 0 ||
 659                              select_timeout.tv_usec > 50000)) {
 660                                 select_timeout.tv_sec  = 0;
 661                                 select_timeout.tv_usec = 50000;
 662                         }
 663
 664                         select(max_fd+1, &readfds, &writefds, &excfds, &select_timeout);
 665                 }
 666         }
 667 #else
 668         while (slot->in_use) {
 669                 slot->curl_result = curl_easy_perform(slot->curl);
 670                 finish_active_slot(slot);
 671         }
 672 #endif
 673 }
 674
 675 static void closedown_active_slot(struct active_request_slot *slot)
 676 {
 677         active_requests--;
 678         slot->in_use = 0;
 679 }
 680
 681 static void release_active_slot(struct active_request_slot *slot)
 682 {
 683         closedown_active_slot(slot);
 684         if (slot->curl && curl_session_count > min_curl_sessions) {
 685 #ifdef USE_CURL_MULTI
 686                 curl_multi_remove_handle(curlm, slot->curl);
 687 #endif
 688                 curl_easy_cleanup(slot->curl);
 689                 slot->curl = NULL;
 690                 curl_session_count--;
 691         }
 692 #ifdef USE_CURL_MULTI
 693         fill_active_slots();
 694 #endif
 695 }
 696
 697 void finish_active_slot(struct active_request_slot *slot)
 698 {
 699         closedown_active_slot(slot);
 700         curl_easy_getinfo(slot->curl, CURLINFO_HTTP_CODE, &slot->http_code);
 701
 702         if (slot->finished != NULL)
 703                 (*slot->finished) = 1;
 704
 705         /* Store slot results so they can be read after the slot is reused */
 706         if (slot->results != NULL) {
 707                 slot->results->curl_result = slot->curl_result;
 708                 slot->results->http_code = slot->http_code;
 709         }
 710
 711         /* Run callback if appropriate */
 712         if (slot->callback_func != NULL)
 713                 slot->callback_func(slot->callback_data);
 714 }
 715
 716 void finish_all_active_slots(void)
 717 {
 718         struct active_request_slot *slot = active_queue_head;
 719
 720         while (slot != NULL)
 721                 if (slot->in_use) {
 722                         run_active_slot(slot);
 723                         slot = active_queue_head;
 724                 } else {
 725                         slot = slot->next;
 726                 }
 727 }
 728
 729 /* Helpers for modifying and creating URLs */
 730 static inline int needs_quote(int ch)
 731 {
 732         if (((ch >= 'A') && (ch <= 'Z'))
 733                         || ((ch >= 'a') && (ch <= 'z'))
 734                         || ((ch >= '0') && (ch <= '9'))
 735                         || (ch == '/')
 736                         || (ch == '-')
 737                         || (ch == '.'))
 738                 return 0;
 739         return 1;
 740 }
 741
 742 static char *quote_ref_url(const char *base, const char *ref)
 743 {
 744         struct strbuf buf = STRBUF_INIT;
 745         const char *cp;
 746         int ch;
 747
 748         end_url_with_slash(&buf, base);
 749
 750         for (cp = ref; (ch = *cp) != 0; cp++)
 751                 if (needs_quote(ch))
 752                         strbuf_addf(&buf, "%%%02x", ch);
 753                 else
 754                         strbuf_addch(&buf, *cp);
 755
 756         return strbuf_detach(&buf, NULL);
 757 }
 758
 759 void append_remote_object_url(struct strbuf *buf, const char *url,
 760                               const char *hex,
 761                               int only_two_digit_prefix)
 762 {
 763         end_url_with_slash(buf, url);
 764
 765         strbuf_addf(buf, "objects/%.*s/", 2, hex);
 766         if (!only_two_digit_prefix)
 767                 strbuf_addf(buf, "%s", hex+2);
 768 }
 769
 770 char *get_remote_object_url(const char *url, const char *hex,
 771                             int only_two_digit_prefix)
 772 {
 773         struct strbuf buf = STRBUF_INIT;
 774         append_remote_object_url(&buf, url, hex, only_two_digit_prefix);
 775         return strbuf_detach(&buf, NULL);
 776 }
 777
 778 int handle_curl_result(struct slot_results *results)
 779 {
 780         /*
 781          * If we see a failing http code with CURLE_OK, we have turned off
 782          * FAILONERROR (to keep the server's custom error response), and should
 783          * translate the code into failure here.
 784          */
 785         if (results->curl_result == CURLE_OK &&
 786             results->http_code >= 400) {
 787                 results->curl_result = CURLE_HTTP_RETURNED_ERROR;
 788                 /*
 789                  * Normally curl will already have put the "reason phrase"
 790                  * from the server into curl_errorstr; unfortunately without
 791                  * FAILONERROR it is lost, so we can give only the numeric
 792                  * status code.
 793                  */
 794                 snprintf(curl_errorstr, sizeof(curl_errorstr),
 795                          "The requested URL returned error: %ld",
 796                          results->http_code);
 797         }
 798
 799         if (results->curl_result == CURLE_OK) {
 800                 credential_approve(&http_auth);
 801                 return HTTP_OK;
 802         } else if (missing_target(results))
 803                 return HTTP_MISSING_TARGET;
 804         else if (results->http_code == 401) {
 805                 if (http_auth.username && http_auth.password) {
 806                         credential_reject(&http_auth);
 807                         return HTTP_NOAUTH;
 808                 } else {
 809                         credential_fill(&http_auth);
 810                         return HTTP_REAUTH;
 811                 }
 812         } else {
 813 #if LIBCURL_VERSION_NUM >= 0x070c00
 814                 if (!curl_errorstr[0])
 815                         strlcpy(curl_errorstr,
 816                                 curl_easy_strerror(results->curl_result),
 817                                 sizeof(curl_errorstr));
 818 #endif
 819                 return HTTP_ERROR;
 820         }
 821 }
 822
 823 static CURLcode curlinfo_strbuf(CURL *curl, CURLINFO info, struct strbuf *buf)
 824 {
 825         char *ptr;
 826         CURLcode ret;
 827
 828         strbuf_reset(buf);
 829         ret = curl_easy_getinfo(curl, info, &ptr);
 830         if (!ret && ptr)
 831                 strbuf_addstr(buf, ptr);
 832         return ret;
 833 }
 834
 835 /* http_request() targets */
 836 #define HTTP_REQUEST_STRBUF     0
 837 #define HTTP_REQUEST_FILE       1
 838
 839 static int http_request(const char *url, struct strbuf *type,
 840                         void *result, int target, int options)
 841 {
 842         struct active_request_slot *slot;
 843         struct slot_results results;
 844         struct curl_slist *headers = NULL;
 845         struct strbuf buf = STRBUF_INIT;
 846         int ret;
 847
 848         slot = get_active_slot();
 849         slot->results = &results;
 850         curl_easy_setopt(slot->curl, CURLOPT_HTTPGET, 1);
 851
 852         if (result == NULL) {
 853                 curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 1);
 854         } else {
 855                 curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 0);
 856                 curl_easy_setopt(slot->curl, CURLOPT_FILE, result);
 857
 858                 if (target == HTTP_REQUEST_FILE) {
 859                         long posn = ftell(result);
 860                         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
 861                                          fwrite);
 862                         if (posn > 0) {
 863                                 strbuf_addf(&buf, "Range: bytes=%ld-", posn);
 864                                 headers = curl_slist_append(headers, buf.buf);
 865                                 strbuf_reset(&buf);
 866                         }
 867                 } else
 868                         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
 869                                          fwrite_buffer);
 870         }
 871
 872         strbuf_addstr(&buf, "Pragma:");
 873         if (options & HTTP_NO_CACHE)
 874                 strbuf_addstr(&buf, " no-cache");
 875         if (options & HTTP_KEEP_ERROR)
 876                 curl_easy_setopt(slot->curl, CURLOPT_FAILONERROR, 0);
 877
 878         headers = curl_slist_append(headers, buf.buf);
 879
 880         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 881         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, headers);
 882         curl_easy_setopt(slot->curl, CURLOPT_ENCODING, "gzip");
 883
 884         if (start_active_slot(slot)) {
 885                 run_active_slot(slot);
 886                 ret = handle_curl_result(&results);
 887         } else {
 888                 snprintf(curl_errorstr, sizeof(curl_errorstr),
 889                          "failed to start HTTP request");
 890                 ret = HTTP_START_FAILED;
 891         }
 892
 893         if (type)
 894                 curlinfo_strbuf(slot->curl, CURLINFO_CONTENT_TYPE, type);
 895
 896         curl_slist_free_all(headers);
 897         strbuf_release(&buf);
 898
 899         return ret;
 900 }
 901
 902 static int http_request_reauth(const char *url,
 903                                struct strbuf *type,
 904                                void *result, int target,
 905                                int options)
 906 {
 907         int ret = http_request(url, type, result, target, options);
 908         if (ret != HTTP_REAUTH)
 909                 return ret;
 910
 911         /*
 912          * If we are using KEEP_ERROR, the previous request may have
 913          * put cruft into our output stream; we should clear it out before
 914          * making our next request. We only know how to do this for
 915          * the strbuf case, but that is enough to satisfy current callers.
 916          */
 917         if (options & HTTP_KEEP_ERROR) {
 918                 switch (target) {
 919                 case HTTP_REQUEST_STRBUF:
 920                         strbuf_reset(result);
 921                         break;
 922                 default:
 923                         die("BUG: HTTP_KEEP_ERROR is only supported with strbufs");
 924                 }
 925         }
 926         return http_request(url, type, result, target, options);
 927 }
 928
 929 int http_get_strbuf(const char *url,
 930                     struct strbuf *type,
 931                     struct strbuf *result, int options)
 932 {
 933         return http_request_reauth(url, type, result,
 934                                    HTTP_REQUEST_STRBUF, options);
 935 }
 936
 937 /*
 938  * Downloads a URL and stores the result in the given file.
 939  *
 940  * If a previous interrupted download is detected (i.e. a previous temporary
 941  * file is still around) the download is resumed.
 942  */
 943 static int http_get_file(const char *url, const char *filename, int options)
 944 {
 945         int ret;
 946         struct strbuf tmpfile = STRBUF_INIT;
 947         FILE *result;
 948
 949         strbuf_addf(&tmpfile, "%s.temp", filename);
 950         result = fopen(tmpfile.buf, "a");
 951         if (!result) {
 952                 error("Unable to open local file %s", tmpfile.buf);
 953                 ret = HTTP_ERROR;
 954                 goto cleanup;
 955         }
 956
 957         ret = http_request_reauth(url, NULL, result, HTTP_REQUEST_FILE, options);
 958         fclose(result);
 959
 960         if (ret == HTTP_OK && move_temp_to_file(tmpfile.buf, filename))
 961                 ret = HTTP_ERROR;
 962 cleanup:
 963         strbuf_release(&tmpfile);
 964         return ret;
 965 }
 966
 967 int http_fetch_ref(const char *base, struct ref *ref)
 968 {
 969         char *url;
 970         struct strbuf buffer = STRBUF_INIT;
 971         int ret = -1;
 972
 973         url = quote_ref_url(base, ref->name);
 974         if (http_get_strbuf(url, NULL, &buffer, HTTP_NO_CACHE) == HTTP_OK) {
 975                 strbuf_rtrim(&buffer);
 976                 if (buffer.len == 40)
 977                         ret = get_sha1_hex(buffer.buf, ref->old_sha1);
 978                 else if (!prefixcmp(buffer.buf, "ref: ")) {
 979                         ref->symref = xstrdup(buffer.buf + 5);
 980                         ret = 0;
 981                 }
 982         }
 983
 984         strbuf_release(&buffer);
 985         free(url);
 986         return ret;
 987 }
 988
 989 /* Helpers for fetching packs */
 990 static char *fetch_pack_index(unsigned char *sha1, const char *base_url)
 991 {
 992         char *url, *tmp;
 993         struct strbuf buf = STRBUF_INIT;
 994
 995         if (http_is_verbose)
 996                 fprintf(stderr, "Getting index for pack %s\n", sha1_to_hex(sha1));
 997
 998         end_url_with_slash(&buf, base_url);
 999         strbuf_addf(&buf, "objects/pack/pack-%s.idx", sha1_to_hex(sha1));
1000         url = strbuf_detach(&buf, NULL);
1001
1002         strbuf_addf(&buf, "%s.temp", sha1_pack_index_name(sha1));
1003         tmp = strbuf_detach(&buf, NULL);
1004
1005         if (http_get_file(url, tmp, 0) != HTTP_OK) {
1006                 error("Unable to get pack index %s", url);
1007                 free(tmp);
1008                 tmp = NULL;
1009         }
1010
1011         free(url);
1012         return tmp;
1013 }
1014
1015 static int fetch_and_setup_pack_index(struct packed_git **packs_head,
1016         unsigned char *sha1, const char *base_url)
1017 {
1018         struct packed_git *new_pack;
1019         char *tmp_idx = NULL;
1020         int ret;
1021
1022         if (has_pack_index(sha1)) {
1023                 new_pack = parse_pack_index(sha1, NULL);
1024                 if (!new_pack)
1025                         return -1; /* parse_pack_index() already issued error message */
1026                 goto add_pack;
1027         }
1028
1029         tmp_idx = fetch_pack_index(sha1, base_url);
1030         if (!tmp_idx)
1031                 return -1;
1032
1033         new_pack = parse_pack_index(sha1, tmp_idx);
1034         if (!new_pack) {
1035                 unlink(tmp_idx);
1036                 free(tmp_idx);
1037
1038                 return -1; /* parse_pack_index() already issued error message */
1039         }
1040
1041         ret = verify_pack_index(new_pack);
1042         if (!ret) {
1043                 close_pack_index(new_pack);
1044                 ret = move_temp_to_file(tmp_idx, sha1_pack_index_name(sha1));
1045         }
1046         free(tmp_idx);
1047         if (ret)
1048                 return -1;
1049
1050 add_pack:
1051         new_pack->next = *packs_head;
1052         *packs_head = new_pack;
1053         return 0;
1054 }
1055
1056 int http_get_info_packs(const char *base_url, struct packed_git **packs_head)
1057 {
1058         int ret = 0, i = 0;
1059         char *url, *data;
1060         struct strbuf buf = STRBUF_INIT;
1061         unsigned char sha1[20];
1062
1063         end_url_with_slash(&buf, base_url);
1064         strbuf_addstr(&buf, "objects/info/packs");
1065         url = strbuf_detach(&buf, NULL);
1066
1067         ret = http_get_strbuf(url, NULL, &buf, HTTP_NO_CACHE);
1068         if (ret != HTTP_OK)
1069                 goto cleanup;
1070
1071         data = buf.buf;
1072         while (i < buf.len) {
1073                 switch (data[i]) {
1074                 case 'P':
1075                         i++;
1076                         if (i + 52 <= buf.len &&
1077                             !prefixcmp(data + i, " pack-") &&
1078                             !prefixcmp(data + i + 46, ".pack\n")) {
1079                                 get_sha1_hex(data + i + 6, sha1);
1080                                 fetch_and_setup_pack_index(packs_head, sha1,
1081                                                       base_url);
1082                                 i += 51;
1083                                 break;
1084                         }
1085                 default:
1086                         while (i < buf.len && data[i] != '\n')
1087                                 i++;
1088                 }
1089                 i++;
1090         }
1091
1092 cleanup:
1093         free(url);
1094         return ret;
1095 }
1096
1097 void release_http_pack_request(struct http_pack_request *preq)
1098 {
1099         if (preq->packfile != NULL) {
1100                 fclose(preq->packfile);
1101                 preq->packfile = NULL;
1102         }
1103         if (preq->range_header != NULL) {
1104                 curl_slist_free_all(preq->range_header);
1105                 preq->range_header = NULL;
1106         }
1107         preq->slot = NULL;
1108         free(preq->url);
1109 }
1110
1111 int finish_http_pack_request(struct http_pack_request *preq)
1112 {
1113         struct packed_git **lst;
1114         struct packed_git *p = preq->target;
1115         char *tmp_idx;
1116         struct child_process ip;
1117         const char *ip_argv[8];
1118
1119         close_pack_index(p);
1120
1121         fclose(preq->packfile);
1122         preq->packfile = NULL;
1123
1124         lst = preq->lst;
1125         while (*lst != p)
1126                 lst = &((*lst)->next);
1127         *lst = (*lst)->next;
1128
1129         tmp_idx = xstrdup(preq->tmpfile);
1130         strcpy(tmp_idx + strlen(tmp_idx) - strlen(".pack.temp"),
1131                ".idx.temp");
1132
1133         ip_argv[0] = "index-pack";
1134         ip_argv[1] = "-o";
1135         ip_argv[2] = tmp_idx;
1136         ip_argv[3] = preq->tmpfile;
1137         ip_argv[4] = NULL;
1138
1139         memset(&ip, 0, sizeof(ip));
1140         ip.argv = ip_argv;
1141         ip.git_cmd = 1;
1142         ip.no_stdin = 1;
1143         ip.no_stdout = 1;
1144
1145         if (run_command(&ip)) {
1146                 unlink(preq->tmpfile);
1147                 unlink(tmp_idx);
1148                 free(tmp_idx);
1149                 return -1;
1150         }
1151
1152         unlink(sha1_pack_index_name(p->sha1));
1153
1154         if (move_temp_to_file(preq->tmpfile, sha1_pack_name(p->sha1))
1155          || move_temp_to_file(tmp_idx, sha1_pack_index_name(p->sha1))) {
1156                 free(tmp_idx);
1157                 return -1;
1158         }
1159
1160         install_packed_git(p);
1161         free(tmp_idx);
1162         return 0;
1163 }
1164
1165 struct http_pack_request *new_http_pack_request(
1166         struct packed_git *target, const char *base_url)
1167 {
1168         long prev_posn = 0;
1169         char range[RANGE_HEADER_SIZE];
1170         struct strbuf buf = STRBUF_INIT;
1171         struct http_pack_request *preq;
1172
1173         preq = xcalloc(1, sizeof(*preq));
1174         preq->target = target;
1175
1176         end_url_with_slash(&buf, base_url);
1177         strbuf_addf(&buf, "objects/pack/pack-%s.pack",
1178                 sha1_to_hex(target->sha1));
1179         preq->url = strbuf_detach(&buf, NULL);
1180
1181         snprintf(preq->tmpfile, sizeof(preq->tmpfile), "%s.temp",
1182                 sha1_pack_name(target->sha1));
1183         preq->packfile = fopen(preq->tmpfile, "a");
1184         if (!preq->packfile) {
1185                 error("Unable to open local file %s for pack",
1186                       preq->tmpfile);
1187                 goto abort;
1188         }
1189
1190         preq->slot = get_active_slot();
1191         curl_easy_setopt(preq->slot->curl, CURLOPT_FILE, preq->packfile);
1192         curl_easy_setopt(preq->slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
1193         curl_easy_setopt(preq->slot->curl, CURLOPT_URL, preq->url);
1194         curl_easy_setopt(preq->slot->curl, CURLOPT_HTTPHEADER,
1195                 no_pragma_header);
1196
1197         /*
1198          * If there is data present from a previous transfer attempt,
1199          * resume where it left off
1200          */
1201         prev_posn = ftell(preq->packfile);
1202         if (prev_posn>0) {
1203                 if (http_is_verbose)
1204                         fprintf(stderr,
1205                                 "Resuming fetch of pack %s at byte %ld\n",
1206                                 sha1_to_hex(target->sha1), prev_posn);
1207                 sprintf(range, "Range: bytes=%ld-", prev_posn);
1208                 preq->range_header = curl_slist_append(NULL, range);
1209                 curl_easy_setopt(preq->slot->curl, CURLOPT_HTTPHEADER,
1210                         preq->range_header);
1211         }
1212
1213         return preq;
1214
1215 abort:
1216         free(preq->url);
1217         free(preq);
1218         return NULL;
1219 }
1220
1221 /* Helpers for fetching objects (loose) */
1222 static size_t fwrite_sha1_file(char *ptr, size_t eltsize, size_t nmemb,
1223                                void *data)
1224 {
1225         unsigned char expn[4096];
1226         size_t size = eltsize * nmemb;
1227         int posn = 0;
1228         struct http_object_request *freq =
1229                 (struct http_object_request *)data;
1230         do {
1231                 ssize_t retval = xwrite(freq->localfile,
1232                                         (char *) ptr + posn, size - posn);
1233                 if (retval < 0)
1234                         return posn;
1235                 posn += retval;
1236         } while (posn < size);
1237
1238         freq->stream.avail_in = size;
1239         freq->stream.next_in = (void *)ptr;
1240         do {
1241                 freq->stream.next_out = expn;
1242                 freq->stream.avail_out = sizeof(expn);
1243                 freq->zret = git_inflate(&freq->stream, Z_SYNC_FLUSH);
1244                 git_SHA1_Update(&freq->c, expn,
1245                                 sizeof(expn) - freq->stream.avail_out);
1246         } while (freq->stream.avail_in && freq->zret == Z_OK);
1247         return size;
1248 }
1249
1250 struct http_object_request *new_http_object_request(const char *base_url,
1251         unsigned char *sha1)
1252 {
1253         char *hex = sha1_to_hex(sha1);
1254         char *filename;
1255         char prevfile[PATH_MAX];
1256         int prevlocal;
1257         char prev_buf[PREV_BUF_SIZE];
1258         ssize_t prev_read = 0;
1259         long prev_posn = 0;
1260         char range[RANGE_HEADER_SIZE];
1261         struct curl_slist *range_header = NULL;
1262         struct http_object_request *freq;
1263
1264         freq = xcalloc(1, sizeof(*freq));
1265         hashcpy(freq->sha1, sha1);
1266         freq->localfile = -1;
1267
1268         filename = sha1_file_name(sha1);
1269         snprintf(freq->tmpfile, sizeof(freq->tmpfile),
1270                  "%s.temp", filename);
1271
1272         snprintf(prevfile, sizeof(prevfile), "%s.prev", filename);
1273         unlink_or_warn(prevfile);
1274         rename(freq->tmpfile, prevfile);
1275         unlink_or_warn(freq->tmpfile);
1276
1277         if (freq->localfile != -1)
1278                 error("fd leakage in start: %d", freq->localfile);
1279         freq->localfile = open(freq->tmpfile,
1280                                O_WRONLY | O_CREAT | O_EXCL, 0666);
1281         /*
1282          * This could have failed due to the "lazy directory creation";
1283          * try to mkdir the last path component.
1284          */
1285         if (freq->localfile < 0 && errno == ENOENT) {
1286                 char *dir = strrchr(freq->tmpfile, '/');
1287                 if (dir) {
1288                         *dir = 0;
1289                         mkdir(freq->tmpfile, 0777);
1290                         *dir = '/';
1291                 }
1292                 freq->localfile = open(freq->tmpfile,
1293                                        O_WRONLY | O_CREAT | O_EXCL, 0666);
1294         }
1295
1296         if (freq->localfile < 0) {
1297                 error("Couldn't create temporary file %s: %s",
1298                       freq->tmpfile, strerror(errno));
1299                 goto abort;
1300         }
1301
1302         git_inflate_init(&freq->stream);
1303
1304         git_SHA1_Init(&freq->c);
1305
1306         freq->url = get_remote_object_url(base_url, hex, 0);
1307
1308         /*
1309          * If a previous temp file is present, process what was already
1310          * fetched.
1311          */
1312         prevlocal = open(prevfile, O_RDONLY);
1313         if (prevlocal != -1) {
1314                 do {
1315                         prev_read = xread(prevlocal, prev_buf, PREV_BUF_SIZE);
1316                         if (prev_read>0) {
1317                                 if (fwrite_sha1_file(prev_buf,
1318                                                      1,
1319                                                      prev_read,
1320                                                      freq) == prev_read) {
1321                                         prev_posn += prev_read;
1322                                 } else {
1323                                         prev_read = -1;
1324                                 }
1325                         }
1326                 } while (prev_read > 0);
1327                 close(prevlocal);
1328         }
1329         unlink_or_warn(prevfile);
1330
1331         /*
1332          * Reset inflate/SHA1 if there was an error reading the previous temp
1333          * file; also rewind to the beginning of the local file.
1334          */
1335         if (prev_read == -1) {
1336                 memset(&freq->stream, 0, sizeof(freq->stream));
1337                 git_inflate_init(&freq->stream);
1338                 git_SHA1_Init(&freq->c);
1339                 if (prev_posn>0) {
1340                         prev_posn = 0;
1341                         lseek(freq->localfile, 0, SEEK_SET);
1342                         if (ftruncate(freq->localfile, 0) < 0) {
1343                                 error("Couldn't truncate temporary file %s: %s",
1344                                           freq->tmpfile, strerror(errno));
1345                                 goto abort;
1346                         }
1347                 }
1348         }
1349
1350         freq->slot = get_active_slot();
1351
1352         curl_easy_setopt(freq->slot->curl, CURLOPT_FILE, freq);
1353         curl_easy_setopt(freq->slot->curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);
1354         curl_easy_setopt(freq->slot->curl, CURLOPT_ERRORBUFFER, freq->errorstr);
1355         curl_easy_setopt(freq->slot->curl, CURLOPT_URL, freq->url);
1356         curl_easy_setopt(freq->slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
1357
1358         /*
1359          * If we have successfully processed data from a previous fetch
1360          * attempt, only fetch the data we don't already have.
1361          */
1362         if (prev_posn>0) {
1363                 if (http_is_verbose)
1364                         fprintf(stderr,
1365                                 "Resuming fetch of object %s at byte %ld\n",
1366                                 hex, prev_posn);
1367                 sprintf(range, "Range: bytes=%ld-", prev_posn);
1368                 range_header = curl_slist_append(range_header, range);
1369                 curl_easy_setopt(freq->slot->curl,
1370                                  CURLOPT_HTTPHEADER, range_header);
1371         }
1372
1373         return freq;
1374
1375 abort:
1376         free(freq->url);
1377         free(freq);
1378         return NULL;
1379 }
1380
1381 void process_http_object_request(struct http_object_request *freq)
1382 {
1383         if (freq->slot == NULL)
1384                 return;
1385         freq->curl_result = freq->slot->curl_result;
1386         freq->http_code = freq->slot->http_code;
1387         freq->slot = NULL;
1388 }
1389
1390 int finish_http_object_request(struct http_object_request *freq)
1391 {
1392         struct stat st;
1393
1394         close(freq->localfile);
1395         freq->localfile = -1;
1396
1397         process_http_object_request(freq);
1398
1399         if (freq->http_code == 416) {
1400                 warning("requested range invalid; we may already have all the data.");
1401         } else if (freq->curl_result != CURLE_OK) {
1402                 if (stat(freq->tmpfile, &st) == 0)
1403                         if (st.st_size == 0)
1404                                 unlink_or_warn(freq->tmpfile);
1405                 return -1;
1406         }
1407
1408         git_inflate_end(&freq->stream);
1409         git_SHA1_Final(freq->real_sha1, &freq->c);
1410         if (freq->zret != Z_STREAM_END) {
1411                 unlink_or_warn(freq->tmpfile);
1412                 return -1;
1413         }
1414         if (hashcmp(freq->sha1, freq->real_sha1)) {
1415                 unlink_or_warn(freq->tmpfile);
1416                 return -1;
1417         }
1418         freq->rename =
1419                 move_temp_to_file(freq->tmpfile, sha1_file_name(freq->sha1));
1420
1421         return freq->rename;
1422 }
1423
1424 void abort_http_object_request(struct http_object_request *freq)
1425 {
1426         unlink_or_warn(freq->tmpfile);
1427
1428         release_http_object_request(freq);
1429 }
1430
1431 void release_http_object_request(struct http_object_request *freq)
1432 {
1433         if (freq->localfile != -1) {
1434                 close(freq->localfile);
1435                 freq->localfile = -1;
1436         }
1437         if (freq->url != NULL) {
1438                 free(freq->url);
1439                 freq->url = NULL;
1440         }
1441         if (freq->slot != NULL) {
1442                 freq->slot->callback_func = NULL;
1443                 freq->slot->callback_data = NULL;
1444                 release_active_slot(freq->slot);
1445                 freq->slot = NULL;
1446         }
1447 }