git.oblomov.eu Git - git/blob - 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 "urlmatch.h"
   7 #include "credential.h"
   8 #include "version.h"
   9 #include "pkt-line.h"
  10
  11 int active_requests;
  12 int http_is_verbose;
  13 size_t http_post_buffer = 16 * LARGE_PACKET_MAX;
  14
  15 #if LIBCURL_VERSION_NUM >= 0x070a06
  16 #define LIBCURL_CAN_HANDLE_AUTH_ANY
  17 #endif
  18
  19 static int min_curl_sessions = 1;
  20 static int curl_session_count;
  21 #ifdef USE_CURL_MULTI
  22 static int max_requests = -1;
  23 static CURLM *curlm;
  24 #endif
  25 #ifndef NO_CURL_EASY_DUPHANDLE
  26 static CURL *curl_default;
  27 #endif
  28
  29 #define PREV_BUF_SIZE 4096
  30 #define RANGE_HEADER_SIZE 30
  31
  32 char curl_errorstr[CURL_ERROR_SIZE];
  33
  34 static int curl_ssl_verify = -1;
  35 static int curl_ssl_try;
  36 static const char *ssl_cert;
  37 #if LIBCURL_VERSION_NUM >= 0x070903
  38 static const char *ssl_key;
  39 #endif
  40 #if LIBCURL_VERSION_NUM >= 0x070908
  41 static const char *ssl_capath;
  42 #endif
  43 static const char *ssl_cainfo;
  44 static long curl_low_speed_limit = -1;
  45 static long curl_low_speed_time = -1;
  46 static int curl_ftp_no_epsv;
  47 static const char *curl_http_proxy;
  48 static const char *curl_cookie_file;
  49 static int curl_save_cookies;
  50 struct credential http_auth = CREDENTIAL_INIT;
  51 static int http_proactive_auth;
  52 static const char *user_agent;
  53
  54 #if LIBCURL_VERSION_NUM >= 0x071700
  55 /* Use CURLOPT_KEYPASSWD as is */
  56 #elif LIBCURL_VERSION_NUM >= 0x070903
  57 #define CURLOPT_KEYPASSWD CURLOPT_SSLKEYPASSWD
  58 #else
  59 #define CURLOPT_KEYPASSWD CURLOPT_SSLCERTPASSWD
  60 #endif
  61
  62 static struct credential cert_auth = CREDENTIAL_INIT;
  63 static int ssl_cert_password_required;
  64
  65 static struct curl_slist *pragma_header;
  66 static struct curl_slist *no_pragma_header;
  67
  68 static struct active_request_slot *active_queue_head;
  69
  70 size_t fread_buffer(char *ptr, size_t eltsize, size_t nmemb, void *buffer_)
  71 {
  72         size_t size = eltsize * nmemb;
  73         struct buffer *buffer = buffer_;
  74
  75         if (size > buffer->buf.len - buffer->posn)
  76                 size = buffer->buf.len - buffer->posn;
  77         memcpy(ptr, buffer->buf.buf + buffer->posn, size);
  78         buffer->posn += size;
  79
  80         return size;
  81 }
  82
  83 #ifndef NO_CURL_IOCTL
  84 curlioerr ioctl_buffer(CURL *handle, int cmd, void *clientp)
  85 {
  86         struct buffer *buffer = clientp;
  87
  88         switch (cmd) {
  89         case CURLIOCMD_NOP:
  90                 return CURLIOE_OK;
  91
  92         case CURLIOCMD_RESTARTREAD:
  93                 buffer->posn = 0;
  94                 return CURLIOE_OK;
  95
  96         default:
  97                 return CURLIOE_UNKNOWNCMD;
  98         }
  99 }
 100 #endif
 101
 102 size_t fwrite_buffer(char *ptr, size_t eltsize, size_t nmemb, void *buffer_)
 103 {
 104         size_t size = eltsize * nmemb;
 105         struct strbuf *buffer = buffer_;
 106
 107         strbuf_add(buffer, ptr, size);
 108         return size;
 109 }
 110
 111 size_t fwrite_null(char *ptr, size_t eltsize, size_t nmemb, void *strbuf)
 112 {
 113         return eltsize * nmemb;
 114 }
 115
 116 #ifdef USE_CURL_MULTI
 117 static void process_curl_messages(void)
 118 {
 119         int num_messages;
 120         struct active_request_slot *slot;
 121         CURLMsg *curl_message = curl_multi_info_read(curlm, &num_messages);
 122
 123         while (curl_message != NULL) {
 124                 if (curl_message->msg == CURLMSG_DONE) {
 125                         int curl_result = curl_message->data.result;
 126                         slot = active_queue_head;
 127                         while (slot != NULL &&
 128                                slot->curl != curl_message->easy_handle)
 129                                 slot = slot->next;
 130                         if (slot != NULL) {
 131                                 curl_multi_remove_handle(curlm, slot->curl);
 132                                 slot->curl_result = curl_result;
 133                                 finish_active_slot(slot);
 134                         } else {
 135                                 fprintf(stderr, "Received DONE message for unknown request!\n");
 136                         }
 137                 } else {
 138                         fprintf(stderr, "Unknown CURL message received: %d\n",
 139                                 (int)curl_message->msg);
 140                 }
 141                 curl_message = curl_multi_info_read(curlm, &num_messages);
 142         }
 143 }
 144 #endif
 145
 146 static int http_options(const char *var, const char *value, void *cb)
 147 {
 148         if (!strcmp("http.sslverify", var)) {
 149                 curl_ssl_verify = git_config_bool(var, value);
 150                 return 0;
 151         }
 152         if (!strcmp("http.sslcert", var))
 153                 return git_config_string(&ssl_cert, var, value);
 154 #if LIBCURL_VERSION_NUM >= 0x070903
 155         if (!strcmp("http.sslkey", var))
 156                 return git_config_string(&ssl_key, var, value);
 157 #endif
 158 #if LIBCURL_VERSION_NUM >= 0x070908
 159         if (!strcmp("http.sslcapath", var))
 160                 return git_config_string(&ssl_capath, var, value);
 161 #endif
 162         if (!strcmp("http.sslcainfo", var))
 163                 return git_config_string(&ssl_cainfo, var, value);
 164         if (!strcmp("http.sslcertpasswordprotected", var)) {
 165                 ssl_cert_password_required = git_config_bool(var, value);
 166                 return 0;
 167         }
 168         if (!strcmp("http.ssltry", var)) {
 169                 curl_ssl_try = git_config_bool(var, value);
 170                 return 0;
 171         }
 172         if (!strcmp("http.minsessions", var)) {
 173                 min_curl_sessions = git_config_int(var, value);
 174 #ifndef USE_CURL_MULTI
 175                 if (min_curl_sessions > 1)
 176                         min_curl_sessions = 1;
 177 #endif
 178                 return 0;
 179         }
 180 #ifdef USE_CURL_MULTI
 181         if (!strcmp("http.maxrequests", var)) {
 182                 max_requests = git_config_int(var, value);
 183                 return 0;
 184         }
 185 #endif
 186         if (!strcmp("http.lowspeedlimit", var)) {
 187                 curl_low_speed_limit = (long)git_config_int(var, value);
 188                 return 0;
 189         }
 190         if (!strcmp("http.lowspeedtime", var)) {
 191                 curl_low_speed_time = (long)git_config_int(var, value);
 192                 return 0;
 193         }
 194
 195         if (!strcmp("http.noepsv", var)) {
 196                 curl_ftp_no_epsv = git_config_bool(var, value);
 197                 return 0;
 198         }
 199         if (!strcmp("http.proxy", var))
 200                 return git_config_string(&curl_http_proxy, var, value);
 201
 202         if (!strcmp("http.cookiefile", var))
 203                 return git_config_string(&curl_cookie_file, var, value);
 204         if (!strcmp("http.savecookies", var)) {
 205                 curl_save_cookies = git_config_bool(var, value);
 206                 return 0;
 207         }
 208
 209         if (!strcmp("http.postbuffer", var)) {
 210                 http_post_buffer = git_config_int(var, value);
 211                 if (http_post_buffer < LARGE_PACKET_MAX)
 212                         http_post_buffer = LARGE_PACKET_MAX;
 213                 return 0;
 214         }
 215
 216         if (!strcmp("http.useragent", var))
 217                 return git_config_string(&user_agent, var, value);
 218
 219         /* Fall back on the default ones */
 220         return git_default_config(var, value, cb);
 221 }
 222
 223 static void init_curl_http_auth(CURL *result)
 224 {
 225         if (!http_auth.username)
 226                 return;
 227
 228         credential_fill(&http_auth);
 229
 230 #if LIBCURL_VERSION_NUM >= 0x071301
 231         curl_easy_setopt(result, CURLOPT_USERNAME, http_auth.username);
 232         curl_easy_setopt(result, CURLOPT_PASSWORD, http_auth.password);
 233 #else
 234         {
 235                 static struct strbuf up = STRBUF_INIT;
 236                 /*
 237                  * Note that we assume we only ever have a single set of
 238                  * credentials in a given program run, so we do not have
 239                  * to worry about updating this buffer, only setting its
 240                  * initial value.
 241                  */
 242                 if (!up.len)
 243                         strbuf_addf(&up, "%s:%s",
 244                                 http_auth.username, http_auth.password);
 245                 curl_easy_setopt(result, CURLOPT_USERPWD, up.buf);
 246         }
 247 #endif
 248 }
 249
 250 static int has_cert_password(void)
 251 {
 252         if (ssl_cert == NULL || ssl_cert_password_required != 1)
 253                 return 0;
 254         if (!cert_auth.password) {
 255                 cert_auth.protocol = xstrdup("cert");
 256                 cert_auth.username = xstrdup("");
 257                 cert_auth.path = xstrdup(ssl_cert);
 258                 credential_fill(&cert_auth);
 259         }
 260         return 1;
 261 }
 262
 263 #if LIBCURL_VERSION_NUM >= 0x071900
 264 static void set_curl_keepalive(CURL *c)
 265 {
 266         curl_easy_setopt(c, CURLOPT_TCP_KEEPALIVE, 1);
 267 }
 268
 269 #elif LIBCURL_VERSION_NUM >= 0x071000
 270 static int sockopt_callback(void *client, curl_socket_t fd, curlsocktype type)
 271 {
 272         int ka = 1;
 273         int rc;
 274         socklen_t len = (socklen_t)sizeof(ka);
 275
 276         if (type != CURLSOCKTYPE_IPCXN)
 277                 return 0;
 278
 279         rc = setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, (void *)&ka, len);
 280         if (rc < 0)
 281                 warning("unable to set SO_KEEPALIVE on socket %s",
 282                         strerror(errno));
 283
 284         return 0; /* CURL_SOCKOPT_OK only exists since curl 7.21.5 */
 285 }
 286
 287 static void set_curl_keepalive(CURL *c)
 288 {
 289         curl_easy_setopt(c, CURLOPT_SOCKOPTFUNCTION, sockopt_callback);
 290 }
 291
 292 #else
 293 static void set_curl_keepalive(CURL *c)
 294 {
 295         /* not supported on older curl versions */
 296 }
 297 #endif
 298
 299 static CURL *get_curl_handle(void)
 300 {
 301         CURL *result = curl_easy_init();
 302
 303         if (!curl_ssl_verify) {
 304                 curl_easy_setopt(result, CURLOPT_SSL_VERIFYPEER, 0);
 305                 curl_easy_setopt(result, CURLOPT_SSL_VERIFYHOST, 0);
 306         } else {
 307                 /* Verify authenticity of the peer's certificate */
 308                 curl_easy_setopt(result, CURLOPT_SSL_VERIFYPEER, 1);
 309                 /* The name in the cert must match whom we tried to connect */
 310                 curl_easy_setopt(result, CURLOPT_SSL_VERIFYHOST, 2);
 311         }
 312
 313 #if LIBCURL_VERSION_NUM >= 0x070907
 314         curl_easy_setopt(result, CURLOPT_NETRC, CURL_NETRC_OPTIONAL);
 315 #endif
 316 #ifdef LIBCURL_CAN_HANDLE_AUTH_ANY
 317         curl_easy_setopt(result, CURLOPT_HTTPAUTH, CURLAUTH_ANY);
 318 #endif
 319
 320         if (http_proactive_auth)
 321                 init_curl_http_auth(result);
 322
 323         if (ssl_cert != NULL)
 324                 curl_easy_setopt(result, CURLOPT_SSLCERT, ssl_cert);
 325         if (has_cert_password())
 326                 curl_easy_setopt(result, CURLOPT_KEYPASSWD, cert_auth.password);
 327 #if LIBCURL_VERSION_NUM >= 0x070903
 328         if (ssl_key != NULL)
 329                 curl_easy_setopt(result, CURLOPT_SSLKEY, ssl_key);
 330 #endif
 331 #if LIBCURL_VERSION_NUM >= 0x070908
 332         if (ssl_capath != NULL)
 333                 curl_easy_setopt(result, CURLOPT_CAPATH, ssl_capath);
 334 #endif
 335         if (ssl_cainfo != NULL)
 336                 curl_easy_setopt(result, CURLOPT_CAINFO, ssl_cainfo);
 337
 338         if (curl_low_speed_limit > 0 && curl_low_speed_time > 0) {
 339                 curl_easy_setopt(result, CURLOPT_LOW_SPEED_LIMIT,
 340                                  curl_low_speed_limit);
 341                 curl_easy_setopt(result, CURLOPT_LOW_SPEED_TIME,
 342                                  curl_low_speed_time);
 343         }
 344
 345         curl_easy_setopt(result, CURLOPT_FOLLOWLOCATION, 1);
 346 #if LIBCURL_VERSION_NUM >= 0x071301
 347         curl_easy_setopt(result, CURLOPT_POSTREDIR, CURL_REDIR_POST_ALL);
 348 #elif LIBCURL_VERSION_NUM >= 0x071101
 349         curl_easy_setopt(result, CURLOPT_POST301, 1);
 350 #endif
 351
 352         if (getenv("GIT_CURL_VERBOSE"))
 353                 curl_easy_setopt(result, CURLOPT_VERBOSE, 1);
 354
 355         curl_easy_setopt(result, CURLOPT_USERAGENT,
 356                 user_agent ? user_agent : git_user_agent());
 357
 358         if (curl_ftp_no_epsv)
 359                 curl_easy_setopt(result, CURLOPT_FTP_USE_EPSV, 0);
 360
 361 #ifdef CURLOPT_USE_SSL
 362         if (curl_ssl_try)
 363                 curl_easy_setopt(result, CURLOPT_USE_SSL, CURLUSESSL_TRY);
 364 #endif
 365
 366         if (curl_http_proxy) {
 367                 curl_easy_setopt(result, CURLOPT_PROXY, curl_http_proxy);
 368                 curl_easy_setopt(result, CURLOPT_PROXYAUTH, CURLAUTH_ANY);
 369         }
 370
 371         set_curl_keepalive(result);
 372
 373         return result;
 374 }
 375
 376 static void set_from_env(const char **var, const char *envname)
 377 {
 378         const char *val = getenv(envname);
 379         if (val)
 380                 *var = val;
 381 }
 382
 383 void http_init(struct remote *remote, const char *url, int proactive_auth)
 384 {
 385         char *low_speed_limit;
 386         char *low_speed_time;
 387         char *normalized_url;
 388         struct urlmatch_config config = { STRING_LIST_INIT_DUP };
 389
 390         config.section = "http";
 391         config.key = NULL;
 392         config.collect_fn = http_options;
 393         config.cascade_fn = git_default_config;
 394         config.cb = NULL;
 395
 396         http_is_verbose = 0;
 397         normalized_url = url_normalize(url, &config.url);
 398
 399         git_config(urlmatch_config_entry, &config);
 400         free(normalized_url);
 401
 402         curl_global_init(CURL_GLOBAL_ALL);
 403
 404         http_proactive_auth = proactive_auth;
 405
 406         if (remote && remote->http_proxy)
 407                 curl_http_proxy = xstrdup(remote->http_proxy);
 408
 409         pragma_header = curl_slist_append(pragma_header, "Pragma: no-cache");
 410         no_pragma_header = curl_slist_append(no_pragma_header, "Pragma:");
 411
 412 #ifdef USE_CURL_MULTI
 413         {
 414                 char *http_max_requests = getenv("GIT_HTTP_MAX_REQUESTS");
 415                 if (http_max_requests != NULL)
 416                         max_requests = atoi(http_max_requests);
 417         }
 418
 419         curlm = curl_multi_init();
 420         if (curlm == NULL) {
 421                 fprintf(stderr, "Error creating curl multi handle.\n");
 422                 exit(1);
 423         }
 424 #endif
 425
 426         if (getenv("GIT_SSL_NO_VERIFY"))
 427                 curl_ssl_verify = 0;
 428
 429         set_from_env(&ssl_cert, "GIT_SSL_CERT");
 430 #if LIBCURL_VERSION_NUM >= 0x070903
 431         set_from_env(&ssl_key, "GIT_SSL_KEY");
 432 #endif
 433 #if LIBCURL_VERSION_NUM >= 0x070908
 434         set_from_env(&ssl_capath, "GIT_SSL_CAPATH");
 435 #endif
 436         set_from_env(&ssl_cainfo, "GIT_SSL_CAINFO");
 437
 438         set_from_env(&user_agent, "GIT_HTTP_USER_AGENT");
 439
 440         low_speed_limit = getenv("GIT_HTTP_LOW_SPEED_LIMIT");
 441         if (low_speed_limit != NULL)
 442                 curl_low_speed_limit = strtol(low_speed_limit, NULL, 10);
 443         low_speed_time = getenv("GIT_HTTP_LOW_SPEED_TIME");
 444         if (low_speed_time != NULL)
 445                 curl_low_speed_time = strtol(low_speed_time, NULL, 10);
 446
 447         if (curl_ssl_verify == -1)
 448                 curl_ssl_verify = 1;
 449
 450         curl_session_count = 0;
 451 #ifdef USE_CURL_MULTI
 452         if (max_requests < 1)
 453                 max_requests = DEFAULT_MAX_REQUESTS;
 454 #endif
 455
 456         if (getenv("GIT_CURL_FTP_NO_EPSV"))
 457                 curl_ftp_no_epsv = 1;
 458
 459         if (url) {
 460                 credential_from_url(&http_auth, url);
 461                 if (!ssl_cert_password_required &&
 462                     getenv("GIT_SSL_CERT_PASSWORD_PROTECTED") &&
 463                     !prefixcmp(url, "https://"))
 464                         ssl_cert_password_required = 1;
 465         }
 466
 467 #ifndef NO_CURL_EASY_DUPHANDLE
 468         curl_default = get_curl_handle();
 469 #endif
 470 }
 471
 472 void http_cleanup(void)
 473 {
 474         struct active_request_slot *slot = active_queue_head;
 475
 476         while (slot != NULL) {
 477                 struct active_request_slot *next = slot->next;
 478                 if (slot->curl != NULL) {
 479 #ifdef USE_CURL_MULTI
 480                         curl_multi_remove_handle(curlm, slot->curl);
 481 #endif
 482                         curl_easy_cleanup(slot->curl);
 483                 }
 484                 free(slot);
 485                 slot = next;
 486         }
 487         active_queue_head = NULL;
 488
 489 #ifndef NO_CURL_EASY_DUPHANDLE
 490         curl_easy_cleanup(curl_default);
 491 #endif
 492
 493 #ifdef USE_CURL_MULTI
 494         curl_multi_cleanup(curlm);
 495 #endif
 496         curl_global_cleanup();
 497
 498         curl_slist_free_all(pragma_header);
 499         pragma_header = NULL;
 500
 501         curl_slist_free_all(no_pragma_header);
 502         no_pragma_header = NULL;
 503
 504         if (curl_http_proxy) {
 505                 free((void *)curl_http_proxy);
 506                 curl_http_proxy = NULL;
 507         }
 508
 509         if (cert_auth.password != NULL) {
 510                 memset(cert_auth.password, 0, strlen(cert_auth.password));
 511                 free(cert_auth.password);
 512                 cert_auth.password = NULL;
 513         }
 514         ssl_cert_password_required = 0;
 515 }
 516
 517 struct active_request_slot *get_active_slot(void)
 518 {
 519         struct active_request_slot *slot = active_queue_head;
 520         struct active_request_slot *newslot;
 521
 522 #ifdef USE_CURL_MULTI
 523         int num_transfers;
 524
 525         /* Wait for a slot to open up if the queue is full */
 526         while (active_requests >= max_requests) {
 527                 curl_multi_perform(curlm, &num_transfers);
 528                 if (num_transfers < active_requests)
 529                         process_curl_messages();
 530         }
 531 #endif
 532
 533         while (slot != NULL && slot->in_use)
 534                 slot = slot->next;
 535
 536         if (slot == NULL) {
 537                 newslot = xmalloc(sizeof(*newslot));
 538                 newslot->curl = NULL;
 539                 newslot->in_use = 0;
 540                 newslot->next = NULL;
 541
 542                 slot = active_queue_head;
 543                 if (slot == NULL) {
 544                         active_queue_head = newslot;
 545                 } else {
 546                         while (slot->next != NULL)
 547                                 slot = slot->next;
 548                         slot->next = newslot;
 549                 }
 550                 slot = newslot;
 551         }
 552
 553         if (slot->curl == NULL) {
 554 #ifdef NO_CURL_EASY_DUPHANDLE
 555                 slot->curl = get_curl_handle();
 556 #else
 557                 slot->curl = curl_easy_duphandle(curl_default);
 558 #endif
 559                 curl_session_count++;
 560         }
 561
 562         active_requests++;
 563         slot->in_use = 1;
 564         slot->results = NULL;
 565         slot->finished = NULL;
 566         slot->callback_data = NULL;
 567         slot->callback_func = NULL;
 568         curl_easy_setopt(slot->curl, CURLOPT_COOKIEFILE, curl_cookie_file);
 569         if (curl_save_cookies)
 570                 curl_easy_setopt(slot->curl, CURLOPT_COOKIEJAR, curl_cookie_file);
 571         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, pragma_header);
 572         curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, curl_errorstr);
 573         curl_easy_setopt(slot->curl, CURLOPT_CUSTOMREQUEST, NULL);
 574         curl_easy_setopt(slot->curl, CURLOPT_READFUNCTION, NULL);
 575         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, NULL);
 576         curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDS, NULL);
 577         curl_easy_setopt(slot->curl, CURLOPT_UPLOAD, 0);
 578         curl_easy_setopt(slot->curl, CURLOPT_HTTPGET, 1);
 579         curl_easy_setopt(slot->curl, CURLOPT_FAILONERROR, 1);
 580         if (http_auth.password)
 581                 init_curl_http_auth(slot->curl);
 582
 583         return slot;
 584 }
 585
 586 int start_active_slot(struct active_request_slot *slot)
 587 {
 588 #ifdef USE_CURL_MULTI
 589         CURLMcode curlm_result = curl_multi_add_handle(curlm, slot->curl);
 590         int num_transfers;
 591
 592         if (curlm_result != CURLM_OK &&
 593             curlm_result != CURLM_CALL_MULTI_PERFORM) {
 594                 active_requests--;
 595                 slot->in_use = 0;
 596                 return 0;
 597         }
 598
 599         /*
 600          * We know there must be something to do, since we just added
 601          * something.
 602          */
 603         curl_multi_perform(curlm, &num_transfers);
 604 #endif
 605         return 1;
 606 }
 607
 608 #ifdef USE_CURL_MULTI
 609 struct fill_chain {
 610         void *data;
 611         int (*fill)(void *);
 612         struct fill_chain *next;
 613 };
 614
 615 static struct fill_chain *fill_cfg;
 616
 617 void add_fill_function(void *data, int (*fill)(void *))
 618 {
 619         struct fill_chain *new = xmalloc(sizeof(*new));
 620         struct fill_chain **linkp = &fill_cfg;
 621         new->data = data;
 622         new->fill = fill;
 623         new->next = NULL;
 624         while (*linkp)
 625                 linkp = &(*linkp)->next;
 626         *linkp = new;
 627 }
 628
 629 void fill_active_slots(void)
 630 {
 631         struct active_request_slot *slot = active_queue_head;
 632
 633         while (active_requests < max_requests) {
 634                 struct fill_chain *fill;
 635                 for (fill = fill_cfg; fill; fill = fill->next)
 636                         if (fill->fill(fill->data))
 637                                 break;
 638
 639                 if (!fill)
 640                         break;
 641         }
 642
 643         while (slot != NULL) {
 644                 if (!slot->in_use && slot->curl != NULL
 645                         && curl_session_count > min_curl_sessions) {
 646                         curl_easy_cleanup(slot->curl);
 647                         slot->curl = NULL;
 648                         curl_session_count--;
 649                 }
 650                 slot = slot->next;
 651         }
 652 }
 653
 654 void step_active_slots(void)
 655 {
 656         int num_transfers;
 657         CURLMcode curlm_result;
 658
 659         do {
 660                 curlm_result = curl_multi_perform(curlm, &num_transfers);
 661         } while (curlm_result == CURLM_CALL_MULTI_PERFORM);
 662         if (num_transfers < active_requests) {
 663                 process_curl_messages();
 664                 fill_active_slots();
 665         }
 666 }
 667 #endif
 668
 669 void run_active_slot(struct active_request_slot *slot)
 670 {
 671 #ifdef USE_CURL_MULTI
 672         fd_set readfds;
 673         fd_set writefds;
 674         fd_set excfds;
 675         int max_fd;
 676         struct timeval select_timeout;
 677         int finished = 0;
 678
 679         slot->finished = &finished;
 680         while (!finished) {
 681                 step_active_slots();
 682
 683                 if (slot->in_use) {
 684 #if LIBCURL_VERSION_NUM >= 0x070f04
 685                         long curl_timeout;
 686                         curl_multi_timeout(curlm, &curl_timeout);
 687                         if (curl_timeout == 0) {
 688                                 continue;
 689                         } else if (curl_timeout == -1) {
 690                                 select_timeout.tv_sec  = 0;
 691                                 select_timeout.tv_usec = 50000;
 692                         } else {
 693                                 select_timeout.tv_sec  =  curl_timeout / 1000;
 694                                 select_timeout.tv_usec = (curl_timeout % 1000) * 1000;
 695                         }
 696 #else
 697                         select_timeout.tv_sec  = 0;
 698                         select_timeout.tv_usec = 50000;
 699 #endif
 700
 701                         max_fd = -1;
 702                         FD_ZERO(&readfds);
 703                         FD_ZERO(&writefds);
 704                         FD_ZERO(&excfds);
 705                         curl_multi_fdset(curlm, &readfds, &writefds, &excfds, &max_fd);
 706
 707                         /*
 708                          * It can happen that curl_multi_timeout returns a pathologically
 709                          * long timeout when curl_multi_fdset returns no file descriptors
 710                          * to read.  See commit message for more details.
 711                          */
 712                         if (max_fd < 0 &&
 713                             (select_timeout.tv_sec > 0 ||
 714                              select_timeout.tv_usec > 50000)) {
 715                                 select_timeout.tv_sec  = 0;
 716                                 select_timeout.tv_usec = 50000;
 717                         }
 718
 719                         select(max_fd+1, &readfds, &writefds, &excfds, &select_timeout);
 720                 }
 721         }
 722 #else
 723         while (slot->in_use) {
 724                 slot->curl_result = curl_easy_perform(slot->curl);
 725                 finish_active_slot(slot);
 726         }
 727 #endif
 728 }
 729
 730 static void closedown_active_slot(struct active_request_slot *slot)
 731 {
 732         active_requests--;
 733         slot->in_use = 0;
 734 }
 735
 736 static void release_active_slot(struct active_request_slot *slot)
 737 {
 738         closedown_active_slot(slot);
 739         if (slot->curl && curl_session_count > min_curl_sessions) {
 740 #ifdef USE_CURL_MULTI
 741                 curl_multi_remove_handle(curlm, slot->curl);
 742 #endif
 743                 curl_easy_cleanup(slot->curl);
 744                 slot->curl = NULL;
 745                 curl_session_count--;
 746         }
 747 #ifdef USE_CURL_MULTI
 748         fill_active_slots();
 749 #endif
 750 }
 751
 752 void finish_active_slot(struct active_request_slot *slot)
 753 {
 754         closedown_active_slot(slot);
 755         curl_easy_getinfo(slot->curl, CURLINFO_HTTP_CODE, &slot->http_code);
 756
 757         if (slot->finished != NULL)
 758                 (*slot->finished) = 1;
 759
 760         /* Store slot results so they can be read after the slot is reused */
 761         if (slot->results != NULL) {
 762                 slot->results->curl_result = slot->curl_result;
 763                 slot->results->http_code = slot->http_code;
 764         }
 765
 766         /* Run callback if appropriate */
 767         if (slot->callback_func != NULL)
 768                 slot->callback_func(slot->callback_data);
 769 }
 770
 771 void finish_all_active_slots(void)
 772 {
 773         struct active_request_slot *slot = active_queue_head;
 774
 775         while (slot != NULL)
 776                 if (slot->in_use) {
 777                         run_active_slot(slot);
 778                         slot = active_queue_head;
 779                 } else {
 780                         slot = slot->next;
 781                 }
 782 }
 783
 784 /* Helpers for modifying and creating URLs */
 785 static inline int needs_quote(int ch)
 786 {
 787         if (((ch >= 'A') && (ch <= 'Z'))
 788                         || ((ch >= 'a') && (ch <= 'z'))
 789                         || ((ch >= '0') && (ch <= '9'))
 790                         || (ch == '/')
 791                         || (ch == '-')
 792                         || (ch == '.'))
 793                 return 0;
 794         return 1;
 795 }
 796
 797 static char *quote_ref_url(const char *base, const char *ref)
 798 {
 799         struct strbuf buf = STRBUF_INIT;
 800         const char *cp;
 801         int ch;
 802
 803         end_url_with_slash(&buf, base);
 804
 805         for (cp = ref; (ch = *cp) != 0; cp++)
 806                 if (needs_quote(ch))
 807                         strbuf_addf(&buf, "%%%02x", ch);
 808                 else
 809                         strbuf_addch(&buf, *cp);
 810
 811         return strbuf_detach(&buf, NULL);
 812 }
 813
 814 void append_remote_object_url(struct strbuf *buf, const char *url,
 815                               const char *hex,
 816                               int only_two_digit_prefix)
 817 {
 818         end_url_with_slash(buf, url);
 819
 820         strbuf_addf(buf, "objects/%.*s/", 2, hex);
 821         if (!only_two_digit_prefix)
 822                 strbuf_addf(buf, "%s", hex+2);
 823 }
 824
 825 char *get_remote_object_url(const char *url, const char *hex,
 826                             int only_two_digit_prefix)
 827 {
 828         struct strbuf buf = STRBUF_INIT;
 829         append_remote_object_url(&buf, url, hex, only_two_digit_prefix);
 830         return strbuf_detach(&buf, NULL);
 831 }
 832
 833 int handle_curl_result(struct slot_results *results)
 834 {
 835         /*
 836          * If we see a failing http code with CURLE_OK, we have turned off
 837          * FAILONERROR (to keep the server's custom error response), and should
 838          * translate the code into failure here.
 839          */
 840         if (results->curl_result == CURLE_OK &&
 841             results->http_code >= 400) {
 842                 results->curl_result = CURLE_HTTP_RETURNED_ERROR;
 843                 /*
 844                  * Normally curl will already have put the "reason phrase"
 845                  * from the server into curl_errorstr; unfortunately without
 846                  * FAILONERROR it is lost, so we can give only the numeric
 847                  * status code.
 848                  */
 849                 snprintf(curl_errorstr, sizeof(curl_errorstr),
 850                          "The requested URL returned error: %ld",
 851                          results->http_code);
 852         }
 853
 854         if (results->curl_result == CURLE_OK) {
 855                 credential_approve(&http_auth);
 856                 return HTTP_OK;
 857         } else if (missing_target(results))
 858                 return HTTP_MISSING_TARGET;
 859         else if (results->http_code == 401) {
 860                 if (http_auth.username && http_auth.password) {
 861                         credential_reject(&http_auth);
 862                         return HTTP_NOAUTH;
 863                 } else {
 864                         return HTTP_REAUTH;
 865                 }
 866         } else {
 867 #if LIBCURL_VERSION_NUM >= 0x070c00
 868                 if (!curl_errorstr[0])
 869                         strlcpy(curl_errorstr,
 870                                 curl_easy_strerror(results->curl_result),
 871                                 sizeof(curl_errorstr));
 872 #endif
 873                 return HTTP_ERROR;
 874         }
 875 }
 876
 877 static CURLcode curlinfo_strbuf(CURL *curl, CURLINFO info, struct strbuf *buf)
 878 {
 879         char *ptr;
 880         CURLcode ret;
 881
 882         strbuf_reset(buf);
 883         ret = curl_easy_getinfo(curl, info, &ptr);
 884         if (!ret && ptr)
 885                 strbuf_addstr(buf, ptr);
 886         return ret;
 887 }
 888
 889 /* http_request() targets */
 890 #define HTTP_REQUEST_STRBUF     0
 891 #define HTTP_REQUEST_FILE       1
 892
 893 static int http_request(const char *url,
 894                         void *result, int target,
 895                         const struct http_get_options *options)
 896 {
 897         struct active_request_slot *slot;
 898         struct slot_results results;
 899         struct curl_slist *headers = NULL;
 900         struct strbuf buf = STRBUF_INIT;
 901         int ret;
 902
 903         slot = get_active_slot();
 904         slot->results = &results;
 905         curl_easy_setopt(slot->curl, CURLOPT_HTTPGET, 1);
 906
 907         if (result == NULL) {
 908                 curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 1);
 909         } else {
 910                 curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 0);
 911                 curl_easy_setopt(slot->curl, CURLOPT_FILE, result);
 912
 913                 if (target == HTTP_REQUEST_FILE) {
 914                         long posn = ftell(result);
 915                         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
 916                                          fwrite);
 917                         if (posn > 0) {
 918                                 strbuf_addf(&buf, "Range: bytes=%ld-", posn);
 919                                 headers = curl_slist_append(headers, buf.buf);
 920                                 strbuf_reset(&buf);
 921                         }
 922                 } else
 923                         curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
 924                                          fwrite_buffer);
 925         }
 926
 927         strbuf_addstr(&buf, "Pragma:");
 928         if (options && options->no_cache)
 929                 strbuf_addstr(&buf, " no-cache");
 930         if (options && options->keep_error)
 931                 curl_easy_setopt(slot->curl, CURLOPT_FAILONERROR, 0);
 932
 933         headers = curl_slist_append(headers, buf.buf);
 934
 935         curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 936         curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, headers);
 937         curl_easy_setopt(slot->curl, CURLOPT_ENCODING, "gzip");
 938
 939         if (start_active_slot(slot)) {
 940                 run_active_slot(slot);
 941                 ret = handle_curl_result(&results);
 942         } else {
 943                 snprintf(curl_errorstr, sizeof(curl_errorstr),
 944                          "failed to start HTTP request");
 945                 ret = HTTP_START_FAILED;
 946         }
 947
 948         if (options && options->content_type)
 949                 curlinfo_strbuf(slot->curl, CURLINFO_CONTENT_TYPE,
 950                                 options->content_type);
 951
 952         if (options && options->effective_url)
 953                 curlinfo_strbuf(slot->curl, CURLINFO_EFFECTIVE_URL,
 954                                 options->effective_url);
 955
 956         curl_slist_free_all(headers);
 957         strbuf_release(&buf);
 958
 959         return ret;
 960 }
 961
 962 /*
 963  * Update the "base" url to a more appropriate value, as deduced by
 964  * redirects seen when requesting a URL starting with "url".
 965  *
 966  * The "asked" parameter is a URL that we asked curl to access, and must begin
 967  * with "base".
 968  *
 969  * The "got" parameter is the URL that curl reported to us as where we ended
 970  * up.
 971  *
 972  * Returns 1 if we updated the base url, 0 otherwise.
 973  *
 974  * Our basic strategy is to compare "base" and "asked" to find the bits
 975  * specific to our request. We then strip those bits off of "got" to yield the
 976  * new base. So for example, if our base is "http://example.com/foo.git",
 977  * and we ask for "http://example.com/foo.git/info/refs", we might end up
 978  * with "https://other.example.com/foo.git/info/refs". We would want the
 979  * new URL to become "https://other.example.com/foo.git".
 980  *
 981  * Note that this assumes a sane redirect scheme. It's entirely possible
 982  * in the example above to end up at a URL that does not even end in
 983  * "info/refs".  In such a case we simply punt, as there is not much we can
 984  * do (and such a scheme is unlikely to represent a real git repository,
 985  * which means we are likely about to abort anyway).
 986  */
 987 static int update_url_from_redirect(struct strbuf *base,
 988                                     const char *asked,
 989                                     const struct strbuf *got)
 990 {
 991         const char *tail;
 992         size_t tail_len;
 993
 994         if (!strcmp(asked, got->buf))
 995                 return 0;
 996
 997         if (prefixcmp(asked, base->buf))
 998                 die("BUG: update_url_from_redirect: %s is not a superset of %s",
 999                     asked, base->buf);
1000
1001         tail = asked + base->len;
1002         tail_len = strlen(tail);
1003
1004         if (got->len < tail_len ||
1005             strcmp(tail, got->buf + got->len - tail_len))
1006                 return 0; /* insane redirect scheme */
1007
1008         strbuf_reset(base);
1009         strbuf_add(base, got->buf, got->len - tail_len);
1010         return 1;
1011 }
1012
1013 static int http_request_reauth(const char *url,
1014                                void *result, int target,
1015                                struct http_get_options *options)
1016 {
1017         int ret = http_request(url, result, target, options);
1018
1019         if (options && options->effective_url && options->base_url) {
1020                 if (update_url_from_redirect(options->base_url,
1021                                              url, options->effective_url)) {
1022                         credential_from_url(&http_auth, options->base_url->buf);
1023                         url = options->effective_url->buf;
1024                 }
1025         }
1026
1027         if (ret != HTTP_REAUTH)
1028                 return ret;
1029
1030         /*
1031          * If we are using KEEP_ERROR, the previous request may have
1032          * put cruft into our output stream; we should clear it out before
1033          * making our next request. We only know how to do this for
1034          * the strbuf case, but that is enough to satisfy current callers.
1035          */
1036         if (options && options->keep_error) {
1037                 switch (target) {
1038                 case HTTP_REQUEST_STRBUF:
1039                         strbuf_reset(result);
1040                         break;
1041                 default:
1042                         die("BUG: HTTP_KEEP_ERROR is only supported with strbufs");
1043                 }
1044         }
1045
1046         credential_fill(&http_auth);
1047
1048         return http_request(url, result, target, options);
1049 }
1050
1051 int http_get_strbuf(const char *url,
1052                     struct strbuf *result,
1053                     struct http_get_options *options)
1054 {
1055         return http_request_reauth(url, result, HTTP_REQUEST_STRBUF, options);
1056 }
1057
1058 /*
1059  * Downloads a URL and stores the result in the given file.
1060  *
1061  * If a previous interrupted download is detected (i.e. a previous temporary
1062  * file is still around) the download is resumed.
1063  */
1064 static int http_get_file(const char *url, const char *filename,
1065                          struct http_get_options *options)
1066 {
1067         int ret;
1068         struct strbuf tmpfile = STRBUF_INIT;
1069         FILE *result;
1070
1071         strbuf_addf(&tmpfile, "%s.temp", filename);
1072         result = fopen(tmpfile.buf, "a");
1073         if (!result) {
1074                 error("Unable to open local file %s", tmpfile.buf);
1075                 ret = HTTP_ERROR;
1076                 goto cleanup;
1077         }
1078
1079         ret = http_request_reauth(url, result, HTTP_REQUEST_FILE, options);
1080         fclose(result);
1081
1082         if (ret == HTTP_OK && move_temp_to_file(tmpfile.buf, filename))
1083                 ret = HTTP_ERROR;
1084 cleanup:
1085         strbuf_release(&tmpfile);
1086         return ret;
1087 }
1088
1089 int http_fetch_ref(const char *base, struct ref *ref)
1090 {
1091         struct http_get_options options = {0};
1092         char *url;
1093         struct strbuf buffer = STRBUF_INIT;
1094         int ret = -1;
1095
1096         options.no_cache = 1;
1097
1098         url = quote_ref_url(base, ref->name);
1099         if (http_get_strbuf(url, &buffer, &options) == HTTP_OK) {
1100                 strbuf_rtrim(&buffer);
1101                 if (buffer.len == 40)
1102                         ret = get_sha1_hex(buffer.buf, ref->old_sha1);
1103                 else if (!prefixcmp(buffer.buf, "ref: ")) {
1104                         ref->symref = xstrdup(buffer.buf + 5);
1105                         ret = 0;
1106                 }
1107         }
1108
1109         strbuf_release(&buffer);
1110         free(url);
1111         return ret;
1112 }
1113
1114 /* Helpers for fetching packs */
1115 static char *fetch_pack_index(unsigned char *sha1, const char *base_url)
1116 {
1117         char *url, *tmp;
1118         struct strbuf buf = STRBUF_INIT;
1119
1120         if (http_is_verbose)
1121                 fprintf(stderr, "Getting index for pack %s\n", sha1_to_hex(sha1));
1122
1123         end_url_with_slash(&buf, base_url);
1124         strbuf_addf(&buf, "objects/pack/pack-%s.idx", sha1_to_hex(sha1));
1125         url = strbuf_detach(&buf, NULL);
1126
1127         strbuf_addf(&buf, "%s.temp", sha1_pack_index_name(sha1));
1128         tmp = strbuf_detach(&buf, NULL);
1129
1130         if (http_get_file(url, tmp, NULL) != HTTP_OK) {
1131                 error("Unable to get pack index %s", url);
1132                 free(tmp);
1133                 tmp = NULL;
1134         }
1135
1136         free(url);
1137         return tmp;
1138 }
1139
1140 static int fetch_and_setup_pack_index(struct packed_git **packs_head,
1141         unsigned char *sha1, const char *base_url)
1142 {
1143         struct packed_git *new_pack;
1144         char *tmp_idx = NULL;
1145         int ret;
1146
1147         if (has_pack_index(sha1)) {
1148                 new_pack = parse_pack_index(sha1, NULL);
1149                 if (!new_pack)
1150                         return -1; /* parse_pack_index() already issued error message */
1151                 goto add_pack;
1152         }
1153
1154         tmp_idx = fetch_pack_index(sha1, base_url);
1155         if (!tmp_idx)
1156                 return -1;
1157
1158         new_pack = parse_pack_index(sha1, tmp_idx);
1159         if (!new_pack) {
1160                 unlink(tmp_idx);
1161                 free(tmp_idx);
1162
1163                 return -1; /* parse_pack_index() already issued error message */
1164         }
1165
1166         ret = verify_pack_index(new_pack);
1167         if (!ret) {
1168                 close_pack_index(new_pack);
1169                 ret = move_temp_to_file(tmp_idx, sha1_pack_index_name(sha1));
1170         }
1171         free(tmp_idx);
1172         if (ret)
1173                 return -1;
1174
1175 add_pack:
1176         new_pack->next = *packs_head;
1177         *packs_head = new_pack;
1178         return 0;
1179 }
1180
1181 int http_get_info_packs(const char *base_url, struct packed_git **packs_head)
1182 {
1183         struct http_get_options options = {0};
1184         int ret = 0, i = 0;
1185         char *url, *data;
1186         struct strbuf buf = STRBUF_INIT;
1187         unsigned char sha1[20];
1188
1189         end_url_with_slash(&buf, base_url);
1190         strbuf_addstr(&buf, "objects/info/packs");
1191         url = strbuf_detach(&buf, NULL);
1192
1193         options.no_cache = 1;
1194         ret = http_get_strbuf(url, &buf, &options);
1195         if (ret != HTTP_OK)
1196                 goto cleanup;
1197
1198         data = buf.buf;
1199         while (i < buf.len) {
1200                 switch (data[i]) {
1201                 case 'P':
1202                         i++;
1203                         if (i + 52 <= buf.len &&
1204                             !prefixcmp(data + i, " pack-") &&
1205                             !prefixcmp(data + i + 46, ".pack\n")) {
1206                                 get_sha1_hex(data + i + 6, sha1);
1207                                 fetch_and_setup_pack_index(packs_head, sha1,
1208                                                       base_url);
1209                                 i += 51;
1210                                 break;
1211                         }
1212                 default:
1213                         while (i < buf.len && data[i] != '\n')
1214                                 i++;
1215                 }
1216                 i++;
1217         }
1218
1219 cleanup:
1220         free(url);
1221         return ret;
1222 }
1223
1224 void release_http_pack_request(struct http_pack_request *preq)
1225 {
1226         if (preq->packfile != NULL) {
1227                 fclose(preq->packfile);
1228                 preq->packfile = NULL;
1229         }
1230         if (preq->range_header != NULL) {
1231                 curl_slist_free_all(preq->range_header);
1232                 preq->range_header = NULL;
1233         }
1234         preq->slot = NULL;
1235         free(preq->url);
1236 }
1237
1238 int finish_http_pack_request(struct http_pack_request *preq)
1239 {
1240         struct packed_git **lst;
1241         struct packed_git *p = preq->target;
1242         char *tmp_idx;
1243         struct child_process ip;
1244         const char *ip_argv[8];
1245
1246         close_pack_index(p);
1247
1248         fclose(preq->packfile);
1249         preq->packfile = NULL;
1250
1251         lst = preq->lst;
1252         while (*lst != p)
1253                 lst = &((*lst)->next);
1254         *lst = (*lst)->next;
1255
1256         tmp_idx = xstrdup(preq->tmpfile);
1257         strcpy(tmp_idx + strlen(tmp_idx) - strlen(".pack.temp"),
1258                ".idx.temp");
1259
1260         ip_argv[0] = "index-pack";
1261         ip_argv[1] = "-o";
1262         ip_argv[2] = tmp_idx;
1263         ip_argv[3] = preq->tmpfile;
1264         ip_argv[4] = NULL;
1265
1266         memset(&ip, 0, sizeof(ip));
1267         ip.argv = ip_argv;
1268         ip.git_cmd = 1;
1269         ip.no_stdin = 1;
1270         ip.no_stdout = 1;
1271
1272         if (run_command(&ip)) {
1273                 unlink(preq->tmpfile);
1274                 unlink(tmp_idx);
1275                 free(tmp_idx);
1276                 return -1;
1277         }
1278
1279         unlink(sha1_pack_index_name(p->sha1));
1280
1281         if (move_temp_to_file(preq->tmpfile, sha1_pack_name(p->sha1))
1282          || move_temp_to_file(tmp_idx, sha1_pack_index_name(p->sha1))) {
1283                 free(tmp_idx);
1284                 return -1;
1285         }
1286
1287         install_packed_git(p);
1288         free(tmp_idx);
1289         return 0;
1290 }
1291
1292 struct http_pack_request *new_http_pack_request(
1293         struct packed_git *target, const char *base_url)
1294 {
1295         long prev_posn = 0;
1296         char range[RANGE_HEADER_SIZE];
1297         struct strbuf buf = STRBUF_INIT;
1298         struct http_pack_request *preq;
1299
1300         preq = xcalloc(1, sizeof(*preq));
1301         preq->target = target;
1302
1303         end_url_with_slash(&buf, base_url);
1304         strbuf_addf(&buf, "objects/pack/pack-%s.pack",
1305                 sha1_to_hex(target->sha1));
1306         preq->url = strbuf_detach(&buf, NULL);
1307
1308         snprintf(preq->tmpfile, sizeof(preq->tmpfile), "%s.temp",
1309                 sha1_pack_name(target->sha1));
1310         preq->packfile = fopen(preq->tmpfile, "a");
1311         if (!preq->packfile) {
1312                 error("Unable to open local file %s for pack",
1313                       preq->tmpfile);
1314                 goto abort;
1315         }
1316
1317         preq->slot = get_active_slot();
1318         curl_easy_setopt(preq->slot->curl, CURLOPT_FILE, preq->packfile);
1319         curl_easy_setopt(preq->slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
1320         curl_easy_setopt(preq->slot->curl, CURLOPT_URL, preq->url);
1321         curl_easy_setopt(preq->slot->curl, CURLOPT_HTTPHEADER,
1322                 no_pragma_header);
1323
1324         /*
1325          * If there is data present from a previous transfer attempt,
1326          * resume where it left off
1327          */
1328         prev_posn = ftell(preq->packfile);
1329         if (prev_posn>0) {
1330                 if (http_is_verbose)
1331                         fprintf(stderr,
1332                                 "Resuming fetch of pack %s at byte %ld\n",
1333                                 sha1_to_hex(target->sha1), prev_posn);
1334                 sprintf(range, "Range: bytes=%ld-", prev_posn);
1335                 preq->range_header = curl_slist_append(NULL, range);
1336                 curl_easy_setopt(preq->slot->curl, CURLOPT_HTTPHEADER,
1337                         preq->range_header);
1338         }
1339
1340         return preq;
1341
1342 abort:
1343         free(preq->url);
1344         free(preq);
1345         return NULL;
1346 }
1347
1348 /* Helpers for fetching objects (loose) */
1349 static size_t fwrite_sha1_file(char *ptr, size_t eltsize, size_t nmemb,
1350                                void *data)
1351 {
1352         unsigned char expn[4096];
1353         size_t size = eltsize * nmemb;
1354         int posn = 0;
1355         struct http_object_request *freq =
1356                 (struct http_object_request *)data;
1357         do {
1358                 ssize_t retval = xwrite(freq->localfile,
1359                                         (char *) ptr + posn, size - posn);
1360                 if (retval < 0)
1361                         return posn;
1362                 posn += retval;
1363         } while (posn < size);
1364
1365         freq->stream.avail_in = size;
1366         freq->stream.next_in = (void *)ptr;
1367         do {
1368                 freq->stream.next_out = expn;
1369                 freq->stream.avail_out = sizeof(expn);
1370                 freq->zret = git_inflate(&freq->stream, Z_SYNC_FLUSH);
1371                 git_SHA1_Update(&freq->c, expn,
1372                                 sizeof(expn) - freq->stream.avail_out);
1373         } while (freq->stream.avail_in && freq->zret == Z_OK);
1374         return size;
1375 }
1376
1377 struct http_object_request *new_http_object_request(const char *base_url,
1378         unsigned char *sha1)
1379 {
1380         char *hex = sha1_to_hex(sha1);
1381         char *filename;
1382         char prevfile[PATH_MAX];
1383         int prevlocal;
1384         char prev_buf[PREV_BUF_SIZE];
1385         ssize_t prev_read = 0;
1386         long prev_posn = 0;
1387         char range[RANGE_HEADER_SIZE];
1388         struct curl_slist *range_header = NULL;
1389         struct http_object_request *freq;
1390
1391         freq = xcalloc(1, sizeof(*freq));
1392         hashcpy(freq->sha1, sha1);
1393         freq->localfile = -1;
1394
1395         filename = sha1_file_name(sha1);
1396         snprintf(freq->tmpfile, sizeof(freq->tmpfile),
1397                  "%s.temp", filename);
1398
1399         snprintf(prevfile, sizeof(prevfile), "%s.prev", filename);
1400         unlink_or_warn(prevfile);
1401         rename(freq->tmpfile, prevfile);
1402         unlink_or_warn(freq->tmpfile);
1403
1404         if (freq->localfile != -1)
1405                 error("fd leakage in start: %d", freq->localfile);
1406         freq->localfile = open(freq->tmpfile,
1407                                O_WRONLY | O_CREAT | O_EXCL, 0666);
1408         /*
1409          * This could have failed due to the "lazy directory creation";
1410          * try to mkdir the last path component.
1411          */
1412         if (freq->localfile < 0 && errno == ENOENT) {
1413                 char *dir = strrchr(freq->tmpfile, '/');
1414                 if (dir) {
1415                         *dir = 0;
1416                         mkdir(freq->tmpfile, 0777);
1417                         *dir = '/';
1418                 }
1419                 freq->localfile = open(freq->tmpfile,
1420                                        O_WRONLY | O_CREAT | O_EXCL, 0666);
1421         }
1422
1423         if (freq->localfile < 0) {
1424                 error("Couldn't create temporary file %s: %s",
1425                       freq->tmpfile, strerror(errno));
1426                 goto abort;
1427         }
1428
1429         git_inflate_init(&freq->stream);
1430
1431         git_SHA1_Init(&freq->c);
1432
1433         freq->url = get_remote_object_url(base_url, hex, 0);
1434
1435         /*
1436          * If a previous temp file is present, process what was already
1437          * fetched.
1438          */
1439         prevlocal = open(prevfile, O_RDONLY);
1440         if (prevlocal != -1) {
1441                 do {
1442                         prev_read = xread(prevlocal, prev_buf, PREV_BUF_SIZE);
1443                         if (prev_read>0) {
1444                                 if (fwrite_sha1_file(prev_buf,
1445                                                      1,
1446                                                      prev_read,
1447                                                      freq) == prev_read) {
1448                                         prev_posn += prev_read;
1449                                 } else {
1450                                         prev_read = -1;
1451                                 }
1452                         }
1453                 } while (prev_read > 0);
1454                 close(prevlocal);
1455         }
1456         unlink_or_warn(prevfile);
1457
1458         /*
1459          * Reset inflate/SHA1 if there was an error reading the previous temp
1460          * file; also rewind to the beginning of the local file.
1461          */
1462         if (prev_read == -1) {
1463                 memset(&freq->stream, 0, sizeof(freq->stream));
1464                 git_inflate_init(&freq->stream);
1465                 git_SHA1_Init(&freq->c);
1466                 if (prev_posn>0) {
1467                         prev_posn = 0;
1468                         lseek(freq->localfile, 0, SEEK_SET);
1469                         if (ftruncate(freq->localfile, 0) < 0) {
1470                                 error("Couldn't truncate temporary file %s: %s",
1471                                           freq->tmpfile, strerror(errno));
1472                                 goto abort;
1473                         }
1474                 }
1475         }
1476
1477         freq->slot = get_active_slot();
1478
1479         curl_easy_setopt(freq->slot->curl, CURLOPT_FILE, freq);
1480         curl_easy_setopt(freq->slot->curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);
1481         curl_easy_setopt(freq->slot->curl, CURLOPT_ERRORBUFFER, freq->errorstr);
1482         curl_easy_setopt(freq->slot->curl, CURLOPT_URL, freq->url);
1483         curl_easy_setopt(freq->slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
1484
1485         /*
1486          * If we have successfully processed data from a previous fetch
1487          * attempt, only fetch the data we don't already have.
1488          */
1489         if (prev_posn>0) {
1490                 if (http_is_verbose)
1491                         fprintf(stderr,
1492                                 "Resuming fetch of object %s at byte %ld\n",
1493                                 hex, prev_posn);
1494                 sprintf(range, "Range: bytes=%ld-", prev_posn);
1495                 range_header = curl_slist_append(range_header, range);
1496                 curl_easy_setopt(freq->slot->curl,
1497                                  CURLOPT_HTTPHEADER, range_header);
1498         }
1499
1500         return freq;
1501
1502 abort:
1503         free(freq->url);
1504         free(freq);
1505         return NULL;
1506 }
1507
1508 void process_http_object_request(struct http_object_request *freq)
1509 {
1510         if (freq->slot == NULL)
1511                 return;
1512         freq->curl_result = freq->slot->curl_result;
1513         freq->http_code = freq->slot->http_code;
1514         freq->slot = NULL;
1515 }
1516
1517 int finish_http_object_request(struct http_object_request *freq)
1518 {
1519         struct stat st;
1520
1521         close(freq->localfile);
1522         freq->localfile = -1;
1523
1524         process_http_object_request(freq);
1525
1526         if (freq->http_code == 416) {
1527                 warning("requested range invalid; we may already have all the data.");
1528         } else if (freq->curl_result != CURLE_OK) {
1529                 if (stat(freq->tmpfile, &st) == 0)
1530                         if (st.st_size == 0)
1531                                 unlink_or_warn(freq->tmpfile);
1532                 return -1;
1533         }
1534
1535         git_inflate_end(&freq->stream);
1536         git_SHA1_Final(freq->real_sha1, &freq->c);
1537         if (freq->zret != Z_STREAM_END) {
1538                 unlink_or_warn(freq->tmpfile);
1539                 return -1;
1540         }
1541         if (hashcmp(freq->sha1, freq->real_sha1)) {
1542                 unlink_or_warn(freq->tmpfile);
1543                 return -1;
1544         }
1545         freq->rename =
1546                 move_temp_to_file(freq->tmpfile, sha1_file_name(freq->sha1));
1547
1548         return freq->rename;
1549 }
1550
1551 void abort_http_object_request(struct http_object_request *freq)
1552 {
1553         unlink_or_warn(freq->tmpfile);
1554
1555         release_http_object_request(freq);
1556 }
1557
1558 void release_http_object_request(struct http_object_request *freq)
1559 {
1560         if (freq->localfile != -1) {
1561                 close(freq->localfile);
1562                 freq->localfile = -1;
1563         }
1564         if (freq->url != NULL) {
1565                 free(freq->url);
1566                 freq->url = NULL;
1567         }
1568         if (freq->slot != NULL) {
1569                 freq->slot->callback_func = NULL;
1570                 freq->slot->callback_data = NULL;
1571                 release_active_slot(freq->slot);
1572                 freq->slot = NULL;
1573         }
1574 }