Andrew's git / gitweb.git / http-fetch.c
?
http-fetch.con commit Do not ask for objects known to be complete. (49bb805)
   1#include "cache.h"
   2#include "commit.h"
   3#include "pack.h"
   4#include "fetch.h"
   5
   6#include <curl/curl.h>
   7#include <curl/easy.h>
   8
   9#if LIBCURL_VERSION_NUM >= 0x070908
  10#define USE_CURL_MULTI
  11#define DEFAULT_MAX_REQUESTS 5
  12#endif
  13
  14#if LIBCURL_VERSION_NUM < 0x070704
  15#define curl_global_cleanup() do { /* nothing */ } while(0)
  16#endif
  17#if LIBCURL_VERSION_NUM < 0x070800
  18#define curl_global_init(a) do { /* nothing */ } while(0)
  19#endif
  20
  21#if LIBCURL_VERSION_NUM < 0x070c04
  22#define NO_CURL_EASY_DUPHANDLE
  23#endif
  24
  25#define PREV_BUF_SIZE 4096
  26#define RANGE_HEADER_SIZE 30
  27
  28static int active_requests = 0;
  29static int data_received;
  30
  31#ifdef USE_CURL_MULTI
  32static int max_requests = -1;
  33static CURLM *curlm;
  34#endif
  35#ifndef NO_CURL_EASY_DUPHANDLE
  36static CURL *curl_default;
  37#endif
  38static struct curl_slist *pragma_header;
  39static struct curl_slist *no_pragma_header;
  40static struct curl_slist *no_range_header;
  41static char curl_errorstr[CURL_ERROR_SIZE];
  42
  43struct alt_base
  44{
  45        char *base;
  46        int got_indices;
  47        struct packed_git *packs;
  48        struct alt_base *next;
  49};
  50
  51static struct alt_base *alt = NULL;
  52
  53enum transfer_state {
  54        WAITING,
  55        ABORTED,
  56        ACTIVE,
  57        COMPLETE,
  58};
  59
  60struct transfer_request
  61{
  62        unsigned char sha1[20];
  63        struct alt_base *repo;
  64        char *url;
  65        char filename[PATH_MAX];
  66        char tmpfile[PATH_MAX];
  67        int local;
  68        enum transfer_state state;
  69        CURLcode curl_result;
  70        char errorstr[CURL_ERROR_SIZE];
  71        long http_code;
  72        unsigned char real_sha1[20];
  73        SHA_CTX c;
  74        z_stream stream;
  75        int zret;
  76        int rename;
  77        struct active_request_slot *slot;
  78        struct transfer_request *next;
  79};
  80
  81struct active_request_slot
  82{
  83        CURL *curl;
  84        FILE *local;
  85        int in_use;
  86        int done;
  87        CURLcode curl_result;
  88        struct active_request_slot *next;
  89};
  90
  91static struct transfer_request *request_queue_head = NULL;
  92static struct active_request_slot *active_queue_head = NULL;
  93
  94static int curl_ssl_verify = -1;
  95static char *ssl_cert = NULL;
  96#if LIBCURL_VERSION_NUM >= 0x070902
  97static char *ssl_key = NULL;
  98#endif
  99#if LIBCURL_VERSION_NUM >= 0x070908
 100static char *ssl_capath = NULL;
 101#endif
 102static char *ssl_cainfo = NULL;
 103static long curl_low_speed_limit = -1;
 104static long curl_low_speed_time = -1;
 105
 106struct buffer
 107{
 108        size_t posn;
 109        size_t size;
 110        void *buffer;
 111};
 112
 113static int http_options(const char *var, const char *value)
 114{
 115        if (!strcmp("http.sslverify", var)) {
 116                if (curl_ssl_verify == -1) {
 117                        curl_ssl_verify = git_config_bool(var, value);
 118                }
 119                return 0;
 120        }
 121
 122        if (!strcmp("http.sslcert", var)) {
 123                if (ssl_cert == NULL) {
 124                        ssl_cert = xmalloc(strlen(value)+1);
 125                        strcpy(ssl_cert, value);
 126                }
 127                return 0;
 128        }
 129#if LIBCURL_VERSION_NUM >= 0x070902
 130        if (!strcmp("http.sslkey", var)) {
 131                if (ssl_key == NULL) {
 132                        ssl_key = xmalloc(strlen(value)+1);
 133                        strcpy(ssl_key, value);
 134                }
 135                return 0;
 136        }
 137#endif
 138#if LIBCURL_VERSION_NUM >= 0x070908
 139        if (!strcmp("http.sslcapath", var)) {
 140                if (ssl_capath == NULL) {
 141                        ssl_capath = xmalloc(strlen(value)+1);
 142                        strcpy(ssl_capath, value);
 143                }
 144                return 0;
 145        }
 146#endif
 147        if (!strcmp("http.sslcainfo", var)) {
 148                if (ssl_cainfo == NULL) {
 149                        ssl_cainfo = xmalloc(strlen(value)+1);
 150                        strcpy(ssl_cainfo, value);
 151                }
 152                return 0;
 153        }
 154
 155#ifdef USE_CURL_MULTI   
 156        if (!strcmp("http.maxrequests", var)) {
 157                if (max_requests == -1)
 158                        max_requests = git_config_int(var, value);
 159                return 0;
 160        }
 161#endif
 162
 163        if (!strcmp("http.lowspeedlimit", var)) {
 164                if (curl_low_speed_limit == -1)
 165                        curl_low_speed_limit = (long)git_config_int(var, value);
 166                return 0;
 167        }
 168        if (!strcmp("http.lowspeedtime", var)) {
 169                if (curl_low_speed_time == -1)
 170                        curl_low_speed_time = (long)git_config_int(var, value);
 171                return 0;
 172        }
 173
 174        /* Fall back on the default ones */
 175        return git_default_config(var, value);
 176}
 177
 178static size_t fwrite_buffer(void *ptr, size_t eltsize, size_t nmemb,
 179                            struct buffer *buffer)
 180{
 181        size_t size = eltsize * nmemb;
 182        if (size > buffer->size - buffer->posn)
 183                size = buffer->size - buffer->posn;
 184        memcpy(buffer->buffer + buffer->posn, ptr, size);
 185        buffer->posn += size;
 186        data_received++;
 187        return size;
 188}
 189
 190static size_t fwrite_buffer_dynamic(const void *ptr, size_t eltsize,
 191                                    size_t nmemb, struct buffer *buffer)
 192{
 193        size_t size = eltsize * nmemb;
 194        if (size > buffer->size - buffer->posn) {
 195                buffer->size = buffer->size * 3 / 2;
 196                if (buffer->size < buffer->posn + size)
 197                        buffer->size = buffer->posn + size;
 198                buffer->buffer = xrealloc(buffer->buffer, buffer->size);
 199        }
 200        memcpy(buffer->buffer + buffer->posn, ptr, size);
 201        buffer->posn += size;
 202        data_received++;
 203        return size;
 204}
 205
 206static size_t fwrite_sha1_file(void *ptr, size_t eltsize, size_t nmemb,
 207                               void *data)
 208{
 209        unsigned char expn[4096];
 210        size_t size = eltsize * nmemb;
 211        int posn = 0;
 212        struct transfer_request *request = (struct transfer_request *)data;
 213        do {
 214                ssize_t retval = write(request->local,
 215                                       ptr + posn, size - posn);
 216                if (retval < 0)
 217                        return posn;
 218                posn += retval;
 219        } while (posn < size);
 220
 221        request->stream.avail_in = size;
 222        request->stream.next_in = ptr;
 223        do {
 224                request->stream.next_out = expn;
 225                request->stream.avail_out = sizeof(expn);
 226                request->zret = inflate(&request->stream, Z_SYNC_FLUSH);
 227                SHA1_Update(&request->c, expn,
 228                            sizeof(expn) - request->stream.avail_out);
 229        } while (request->stream.avail_in && request->zret == Z_OK);
 230        data_received++;
 231        return size;
 232}
 233
 234#ifdef USE_CURL_MULTI
 235static void process_curl_messages(void);
 236static void process_request_queue(void);
 237#endif
 238
 239static CURL* get_curl_handle(void)
 240{
 241        CURL* result = curl_easy_init();
 242
 243        curl_easy_setopt(result, CURLOPT_SSL_VERIFYPEER, curl_ssl_verify);
 244#if LIBCURL_VERSION_NUM >= 0x070907
 245        curl_easy_setopt(result, CURLOPT_NETRC, CURL_NETRC_OPTIONAL);
 246#endif
 247
 248        if (ssl_cert != NULL)
 249                curl_easy_setopt(result, CURLOPT_SSLCERT, ssl_cert);
 250#if LIBCURL_VERSION_NUM >= 0x070902
 251        if (ssl_key != NULL)
 252                curl_easy_setopt(result, CURLOPT_SSLKEY, ssl_key);
 253#endif
 254#if LIBCURL_VERSION_NUM >= 0x070908
 255        if (ssl_capath != NULL)
 256                curl_easy_setopt(result, CURLOPT_CAPATH, ssl_capath);
 257#endif
 258        if (ssl_cainfo != NULL)
 259                curl_easy_setopt(result, CURLOPT_CAINFO, ssl_cainfo);
 260        curl_easy_setopt(result, CURLOPT_FAILONERROR, 1);
 261
 262        if (curl_low_speed_limit > 0 && curl_low_speed_time > 0) {
 263                curl_easy_setopt(result, CURLOPT_LOW_SPEED_LIMIT,
 264                                 curl_low_speed_limit);
 265                curl_easy_setopt(result, CURLOPT_LOW_SPEED_TIME,
 266                                 curl_low_speed_time);
 267        }
 268
 269        return result;
 270}
 271
 272static struct active_request_slot *get_active_slot(void)
 273{
 274        struct active_request_slot *slot = active_queue_head;
 275        struct active_request_slot *newslot;
 276
 277#ifdef USE_CURL_MULTI
 278        int num_transfers;
 279
 280        /* Wait for a slot to open up if the queue is full */
 281        while (active_requests >= max_requests) {
 282                curl_multi_perform(curlm, &num_transfers);
 283                if (num_transfers < active_requests) {
 284                        process_curl_messages();
 285                }
 286        }
 287#endif
 288
 289        while (slot != NULL && slot->in_use) {
 290                slot = slot->next;
 291        }
 292        if (slot == NULL) {
 293                newslot = xmalloc(sizeof(*newslot));
 294#ifdef NO_CURL_EASY_DUPHANDLE
 295                newslot->curl = get_curl_handle();
 296#else
 297                newslot->curl = curl_easy_duphandle(curl_default);
 298#endif
 299                newslot->in_use = 0;
 300                newslot->next = NULL;
 301
 302                slot = active_queue_head;
 303                if (slot == NULL) {
 304                        active_queue_head = newslot;
 305                } else {
 306                        while (slot->next != NULL) {
 307                                slot = slot->next;
 308                        }
 309                        slot->next = newslot;
 310                }
 311                slot = newslot;
 312        }
 313
 314        active_requests++;
 315        slot->in_use = 1;
 316        slot->done = 0;
 317        slot->local = NULL;
 318        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, pragma_header);
 319        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_range_header);
 320        curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, curl_errorstr);
 321
 322        return slot;
 323}
 324
 325static int start_active_slot(struct active_request_slot *slot)
 326{
 327#ifdef USE_CURL_MULTI
 328        CURLMcode curlm_result = curl_multi_add_handle(curlm, slot->curl);
 329
 330        if (curlm_result != CURLM_OK &&
 331            curlm_result != CURLM_CALL_MULTI_PERFORM) {
 332                active_requests--;
 333                slot->in_use = 0;
 334                return 0;
 335        }
 336#endif
 337        return 1;
 338}
 339
 340static void run_active_slot(struct active_request_slot *slot)
 341{
 342#ifdef USE_CURL_MULTI
 343        int num_transfers;
 344        long last_pos = 0;
 345        long current_pos;
 346        fd_set readfds;
 347        fd_set writefds;
 348        fd_set excfds;
 349        int max_fd;
 350        struct timeval select_timeout;
 351        CURLMcode curlm_result;
 352
 353        while (!slot->done) {
 354                data_received = 0;
 355                do {
 356                        curlm_result = curl_multi_perform(curlm,
 357                                                          &num_transfers);
 358                } while (curlm_result == CURLM_CALL_MULTI_PERFORM);
 359                if (num_transfers < active_requests) {
 360                        process_curl_messages();
 361                        process_request_queue();
 362                }
 363
 364                if (!data_received && slot->local != NULL) {
 365                        current_pos = ftell(slot->local);
 366                        if (current_pos > last_pos)
 367                                data_received++;
 368                        last_pos = current_pos;
 369                }
 370
 371                if (!slot->done && !data_received) {
 372                        max_fd = 0;
 373                        FD_ZERO(&readfds);
 374                        FD_ZERO(&writefds);
 375                        FD_ZERO(&excfds);
 376                        select_timeout.tv_sec = 0;
 377                        select_timeout.tv_usec = 50000;
 378                        select(max_fd, &readfds, &writefds,
 379                               &excfds, &select_timeout);
 380                }
 381        }
 382#else
 383        slot->curl_result = curl_easy_perform(slot->curl);
 384        active_requests--;
 385#endif
 386}
 387
 388static void start_request(struct transfer_request *request)
 389{
 390        char *hex = sha1_to_hex(request->sha1);
 391        char prevfile[PATH_MAX];
 392        char *url;
 393        char *posn;
 394        int prevlocal;
 395        unsigned char prev_buf[PREV_BUF_SIZE];
 396        ssize_t prev_read = 0;
 397        long prev_posn = 0;
 398        char range[RANGE_HEADER_SIZE];
 399        struct curl_slist *range_header = NULL;
 400        struct active_request_slot *slot;
 401
 402        snprintf(prevfile, sizeof(prevfile), "%s.prev", request->filename);
 403        unlink(prevfile);
 404        rename(request->tmpfile, prevfile);
 405        unlink(request->tmpfile);
 406
 407        request->local = open(request->tmpfile,
 408                              O_WRONLY | O_CREAT | O_EXCL, 0666);
 409        /* This could have failed due to the "lazy directory creation";
 410         * try to mkdir the last path component.
 411         */
 412        if (request->local < 0 && errno == ENOENT) {
 413                char *dir = strrchr(request->tmpfile, '/');
 414                if (dir) {
 415                        *dir = 0;
 416                        mkdir(request->tmpfile, 0777);
 417                        *dir = '/';
 418                }
 419                request->local = open(request->tmpfile,
 420                                      O_WRONLY | O_CREAT | O_EXCL, 0666);
 421        }
 422
 423        if (request->local < 0) {
 424                request->state = ABORTED;
 425                error("Couldn't create temporary file %s for %s: %s\n",
 426                      request->tmpfile, request->filename, strerror(errno));
 427                return;
 428        }
 429
 430        memset(&request->stream, 0, sizeof(request->stream));
 431
 432        inflateInit(&request->stream);
 433
 434        SHA1_Init(&request->c);
 435
 436        url = xmalloc(strlen(request->repo->base) + 50);
 437        request->url = xmalloc(strlen(request->repo->base) + 50);
 438        strcpy(url, request->repo->base);
 439        posn = url + strlen(request->repo->base);
 440        strcpy(posn, "objects/");
 441        posn += 8;
 442        memcpy(posn, hex, 2);
 443        posn += 2;
 444        *(posn++) = '/';
 445        strcpy(posn, hex + 2);
 446        strcpy(request->url, url);
 447
 448        /* If a previous temp file is present, process what was already
 449           fetched. */
 450        prevlocal = open(prevfile, O_RDONLY);
 451        if (prevlocal != -1) {
 452                do {
 453                        prev_read = read(prevlocal, prev_buf, PREV_BUF_SIZE);
 454                        if (prev_read>0) {
 455                                if (fwrite_sha1_file(prev_buf,
 456                                                     1,
 457                                                     prev_read,
 458                                                     request) == prev_read) {
 459                                        prev_posn += prev_read;
 460                                } else {
 461                                        prev_read = -1;
 462                                }
 463                        }
 464                } while (prev_read > 0);
 465                close(prevlocal);
 466        }
 467        unlink(prevfile);
 468
 469        /* Reset inflate/SHA1 if there was an error reading the previous temp
 470           file; also rewind to the beginning of the local file. */
 471        if (prev_read == -1) {
 472                memset(&request->stream, 0, sizeof(request->stream));
 473                inflateInit(&request->stream);
 474                SHA1_Init(&request->c);
 475                if (prev_posn>0) {
 476                        prev_posn = 0;
 477                        lseek(request->local, SEEK_SET, 0);
 478                        ftruncate(request->local, 0);
 479                }
 480        }
 481
 482        slot = get_active_slot();
 483        curl_easy_setopt(slot->curl, CURLOPT_FILE, request);
 484        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);
 485        curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, request->errorstr);
 486        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 487        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 488
 489        /* If we have successfully processed data from a previous fetch
 490           attempt, only fetch the data we don't already have. */
 491        if (prev_posn>0) {
 492                if (get_verbosely)
 493                        fprintf(stderr,
 494                                "Resuming fetch of object %s at byte %ld\n",
 495                                hex, prev_posn);
 496                sprintf(range, "Range: bytes=%ld-", prev_posn);
 497                range_header = curl_slist_append(range_header, range);
 498                curl_easy_setopt(slot->curl,
 499                                 CURLOPT_HTTPHEADER, range_header);
 500        }
 501
 502        /* Try to get the request started, abort the request on error */
 503        if (!start_active_slot(slot)) {
 504                request->state = ABORTED;
 505                close(request->local);
 506                free(request->url);
 507                return;
 508        }
 509        
 510        request->slot = slot;
 511        request->state = ACTIVE;
 512}
 513
 514static void finish_request(struct transfer_request *request)
 515{
 516        fchmod(request->local, 0444);
 517        close(request->local);
 518
 519        if (request->http_code == 416) {
 520                fprintf(stderr, "Warning: requested range invalid; we may already have all the data.\n");
 521        } else if (request->curl_result != CURLE_OK) {
 522                return;
 523        }
 524
 525        inflateEnd(&request->stream);
 526        SHA1_Final(request->real_sha1, &request->c);
 527        if (request->zret != Z_STREAM_END) {
 528                unlink(request->tmpfile);
 529                return;
 530        }
 531        if (memcmp(request->sha1, request->real_sha1, 20)) {
 532                unlink(request->tmpfile);
 533                return;
 534        }
 535        request->rename =
 536                move_temp_to_file(request->tmpfile, request->filename);
 537
 538        if (request->rename == 0)
 539                pull_say("got %s\n", sha1_to_hex(request->sha1));
 540}
 541
 542static void release_request(struct transfer_request *request)
 543{
 544        struct transfer_request *entry = request_queue_head;
 545
 546        if (request == request_queue_head) {
 547                request_queue_head = request->next;
 548        } else {
 549                while (entry->next != NULL && entry->next != request)
 550                        entry = entry->next;
 551                if (entry->next == request)
 552                        entry->next = entry->next->next;
 553        }
 554
 555        free(request->url);
 556        free(request);
 557}
 558
 559#ifdef USE_CURL_MULTI
 560void process_curl_messages(void)
 561{
 562        int num_messages;
 563        struct active_request_slot *slot;
 564        struct transfer_request *request = NULL;
 565        CURLMsg *curl_message = curl_multi_info_read(curlm, &num_messages);
 566
 567        while (curl_message != NULL) {
 568                if (curl_message->msg == CURLMSG_DONE) {
 569                        slot = active_queue_head;
 570                        while (slot != NULL &&
 571                               slot->curl != curl_message->easy_handle)
 572                                slot = slot->next;
 573                        if (slot != NULL) {
 574                                curl_multi_remove_handle(curlm, slot->curl);
 575                                active_requests--;
 576                                slot->done = 1;
 577                                slot->in_use = 0;
 578                                slot->curl_result = curl_message->data.result;
 579                                request = request_queue_head;
 580                                while (request != NULL &&
 581                                       request->slot != slot)
 582                                        request = request->next;
 583                        } else {
 584                                fprintf(stderr, "Received DONE message for unknown request!\n");
 585                        }
 586                        if (request != NULL) {
 587                                request->curl_result =
 588                                        curl_message->data.result;
 589                                curl_easy_getinfo(slot->curl,
 590                                                  CURLINFO_HTTP_CODE,
 591                                                  &request->http_code);
 592                                request->slot = NULL;
 593
 594                                /* Use alternates if necessary */
 595                                if (request->http_code == 404 &&
 596                                    request->repo->next != NULL) {
 597                                        request->repo = request->repo->next;
 598                                        start_request(request);
 599                                } else {
 600                                        finish_request(request);
 601                                        request->state = COMPLETE;
 602                                }
 603                        }
 604                } else {
 605                        fprintf(stderr, "Unknown CURL message received: %d\n",
 606                                (int)curl_message->msg);
 607                }
 608                curl_message = curl_multi_info_read(curlm, &num_messages);
 609        }
 610}
 611
 612void process_request_queue(void)
 613{
 614        struct transfer_request *request = request_queue_head;
 615        int num_transfers;
 616
 617        while (active_requests < max_requests && request != NULL) {
 618                if (request->state == WAITING) {
 619                        if (has_sha1_file(request->sha1))
 620                                release_request(request);
 621                        else
 622                                start_request(request);
 623                        curl_multi_perform(curlm, &num_transfers);
 624                }
 625                request = request->next;
 626        }
 627}
 628#endif
 629
 630void prefetch(unsigned char *sha1)
 631{
 632        struct transfer_request *newreq;
 633        struct transfer_request *tail;
 634        char *filename = sha1_file_name(sha1);
 635
 636        newreq = xmalloc(sizeof(*newreq));
 637        memcpy(newreq->sha1, sha1, 20);
 638        newreq->repo = alt;
 639        newreq->url = NULL;
 640        newreq->local = -1;
 641        newreq->state = WAITING;
 642        snprintf(newreq->filename, sizeof(newreq->filename), "%s", filename);
 643        snprintf(newreq->tmpfile, sizeof(newreq->tmpfile),
 644                 "%s.temp", filename);
 645        newreq->next = NULL;
 646
 647        if (request_queue_head == NULL) {
 648                request_queue_head = newreq;
 649        } else {
 650                tail = request_queue_head;
 651                while (tail->next != NULL) {
 652                        tail = tail->next;
 653                }
 654                tail->next = newreq;
 655        }
 656#ifdef USE_CURL_MULTI
 657        process_request_queue();
 658        process_curl_messages();
 659#endif
 660}
 661
 662static int fetch_index(struct alt_base *repo, unsigned char *sha1)
 663{
 664        char *hex = sha1_to_hex(sha1);
 665        char *filename;
 666        char *url;
 667        char tmpfile[PATH_MAX];
 668        long prev_posn = 0;
 669        char range[RANGE_HEADER_SIZE];
 670        struct curl_slist *range_header = NULL;
 671
 672        FILE *indexfile;
 673        struct active_request_slot *slot;
 674
 675        if (has_pack_index(sha1))
 676                return 0;
 677
 678        if (get_verbosely)
 679                fprintf(stderr, "Getting index for pack %s\n", hex);
 680        
 681        url = xmalloc(strlen(repo->base) + 64);
 682        sprintf(url, "%s/objects/pack/pack-%s.idx", repo->base, hex);
 683        
 684        filename = sha1_pack_index_name(sha1);
 685        snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 686        indexfile = fopen(tmpfile, "a");
 687        if (!indexfile)
 688                return error("Unable to open local file %s for pack index",
 689                             filename);
 690
 691        slot = get_active_slot();
 692        curl_easy_setopt(slot->curl, CURLOPT_FILE, indexfile);
 693        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 694        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 695        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 696        slot->local = indexfile;
 697
 698        /* If there is data present from a previous transfer attempt,
 699           resume where it left off */
 700        prev_posn = ftell(indexfile);
 701        if (prev_posn>0) {
 702                if (get_verbosely)
 703                        fprintf(stderr,
 704                                "Resuming fetch of index for pack %s at byte %ld\n",
 705                                hex, prev_posn);
 706                sprintf(range, "Range: bytes=%ld-", prev_posn);
 707                range_header = curl_slist_append(range_header, range);
 708                curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 709        }
 710
 711        if (start_active_slot(slot)) {
 712                run_active_slot(slot);
 713                if (slot->curl_result != CURLE_OK) {
 714                        fclose(indexfile);
 715                        return error("Unable to get pack index %s\n%s", url,
 716                                     curl_errorstr);
 717                }
 718        } else {
 719                return error("Unable to start request");
 720        }
 721
 722        fclose(indexfile);
 723
 724        return move_temp_to_file(tmpfile, filename);
 725}
 726
 727static int setup_index(struct alt_base *repo, unsigned char *sha1)
 728{
 729        struct packed_git *new_pack;
 730        if (has_pack_file(sha1))
 731                return 0; // don't list this as something we can get
 732
 733        if (fetch_index(repo, sha1))
 734                return -1;
 735
 736        new_pack = parse_pack_index(sha1);
 737        new_pack->next = repo->packs;
 738        repo->packs = new_pack;
 739        return 0;
 740}
 741
 742static int fetch_alternates(char *base)
 743{
 744        int ret = 0;
 745        struct buffer buffer;
 746        char *url;
 747        char *data;
 748        int i = 0;
 749        int http_specific = 1;
 750        struct alt_base *tail = alt;
 751        static const char null_byte = '\0';
 752
 753        struct active_request_slot *slot;
 754
 755        data = xmalloc(4096);
 756        buffer.size = 4096;
 757        buffer.posn = 0;
 758        buffer.buffer = data;
 759
 760        if (get_verbosely)
 761                fprintf(stderr, "Getting alternates list\n");
 762        
 763        url = xmalloc(strlen(base) + 31);
 764        sprintf(url, "%s/objects/info/http-alternates", base);
 765
 766        slot = get_active_slot();
 767        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 768        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
 769                         fwrite_buffer_dynamic);
 770        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 771        if (start_active_slot(slot)) {
 772                run_active_slot(slot);
 773                if (slot->curl_result != CURLE_OK || !buffer.posn) {
 774                        http_specific = 0;
 775
 776                        sprintf(url, "%s/objects/info/alternates", base);
 777
 778                        slot = get_active_slot();
 779                        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 780                        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
 781                                         fwrite_buffer_dynamic);
 782                        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 783                        if (start_active_slot(slot)) {
 784                                run_active_slot(slot);
 785                                if (slot->curl_result != CURLE_OK) {
 786                                        free(buffer.buffer);
 787                                        return 0;
 788                                }
 789                        }
 790                }
 791        } else {
 792                free(buffer.buffer);
 793                return 0;
 794        }
 795
 796        fwrite_buffer_dynamic(&null_byte, 1, 1, &buffer);
 797        buffer.posn--;
 798        data = buffer.buffer;
 799
 800        while (i < buffer.posn) {
 801                int posn = i;
 802                while (posn < buffer.posn && data[posn] != '\n')
 803                        posn++;
 804                if (data[posn] == '\n') {
 805                        int okay = 0;
 806                        int serverlen = 0;
 807                        struct alt_base *newalt;
 808                        char *target = NULL;
 809                        if (data[i] == '/') {
 810                                serverlen = strchr(base + 8, '/') - base;
 811                                okay = 1;
 812                        } else if (!memcmp(data + i, "../", 3)) {
 813                                i += 3;
 814                                serverlen = strlen(base);
 815                                while (i + 2 < posn && 
 816                                       !memcmp(data + i, "../", 3)) {
 817                                        do {
 818                                                serverlen--;
 819                                        } while (serverlen &&
 820                                                 base[serverlen - 1] != '/');
 821                                        i += 3;
 822                                }
 823                                // If the server got removed, give up.
 824                                okay = strchr(base, ':') - base + 3 < 
 825                                        serverlen;
 826                        } else if (http_specific) {
 827                                char *colon = strchr(data + i, ':');
 828                                char *slash = strchr(data + i, '/');
 829                                if (colon && slash && colon < data + posn &&
 830                                    slash < data + posn && colon < slash) {
 831                                        okay = 1;
 832                                }
 833                        }
 834                        // skip 'objects' at end
 835                        if (okay) {
 836                                target = xmalloc(serverlen + posn - i - 6);
 837                                strncpy(target, base, serverlen);
 838                                strncpy(target + serverlen, data + i,
 839                                        posn - i - 7);
 840                                target[serverlen + posn - i - 7] = '\0';
 841                                if (get_verbosely)
 842                                        fprintf(stderr, 
 843                                                "Also look at %s\n", target);
 844                                newalt = xmalloc(sizeof(*newalt));
 845                                newalt->next = NULL;
 846                                newalt->base = target;
 847                                newalt->got_indices = 0;
 848                                newalt->packs = NULL;
 849                                while (tail->next != NULL)
 850                                        tail = tail->next;
 851                                tail->next = newalt;
 852                                ret++;
 853                        }
 854                }
 855                i = posn + 1;
 856        }
 857
 858        free(buffer.buffer);
 859        return ret;
 860}
 861
 862static int fetch_indices(struct alt_base *repo)
 863{
 864        unsigned char sha1[20];
 865        char *url;
 866        struct buffer buffer;
 867        char *data;
 868        int i = 0;
 869
 870        struct active_request_slot *slot;
 871
 872        if (repo->got_indices)
 873                return 0;
 874
 875        data = xmalloc(4096);
 876        buffer.size = 4096;
 877        buffer.posn = 0;
 878        buffer.buffer = data;
 879
 880        if (get_verbosely)
 881                fprintf(stderr, "Getting pack list\n");
 882        
 883        url = xmalloc(strlen(repo->base) + 21);
 884        sprintf(url, "%s/objects/info/packs", repo->base);
 885
 886        slot = get_active_slot();
 887        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 888        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
 889                         fwrite_buffer_dynamic);
 890        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 891        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 892        if (start_active_slot(slot)) {
 893                run_active_slot(slot);
 894                if (slot->curl_result != CURLE_OK) {
 895                        free(buffer.buffer);
 896                        return error("%s", curl_errorstr);
 897                }
 898        } else {
 899                free(buffer.buffer);
 900                return error("Unable to start request");
 901        }
 902
 903        data = buffer.buffer;
 904        while (i < buffer.posn) {
 905                switch (data[i]) {
 906                case 'P':
 907                        i++;
 908                        if (i + 52 < buffer.posn &&
 909                            !strncmp(data + i, " pack-", 6) &&
 910                            !strncmp(data + i + 46, ".pack\n", 6)) {
 911                                get_sha1_hex(data + i + 6, sha1);
 912                                setup_index(repo, sha1);
 913                                i += 51;
 914                                break;
 915                        }
 916                default:
 917                        while (data[i] != '\n')
 918                                i++;
 919                }
 920                i++;
 921        }
 922
 923        free(buffer.buffer);
 924        repo->got_indices = 1;
 925        return 0;
 926}
 927
 928static int fetch_pack(struct alt_base *repo, unsigned char *sha1)
 929{
 930        char *url;
 931        struct packed_git *target;
 932        struct packed_git **lst;
 933        FILE *packfile;
 934        char *filename;
 935        char tmpfile[PATH_MAX];
 936        int ret;
 937        long prev_posn = 0;
 938        char range[RANGE_HEADER_SIZE];
 939        struct curl_slist *range_header = NULL;
 940
 941        struct active_request_slot *slot;
 942
 943        if (fetch_indices(repo))
 944                return -1;
 945        target = find_sha1_pack(sha1, repo->packs);
 946        if (!target)
 947                return -1;
 948
 949        if (get_verbosely) {
 950                fprintf(stderr, "Getting pack %s\n",
 951                        sha1_to_hex(target->sha1));
 952                fprintf(stderr, " which contains %s\n",
 953                        sha1_to_hex(sha1));
 954        }
 955
 956        url = xmalloc(strlen(repo->base) + 65);
 957        sprintf(url, "%s/objects/pack/pack-%s.pack",
 958                repo->base, sha1_to_hex(target->sha1));
 959
 960        filename = sha1_pack_name(target->sha1);
 961        snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 962        packfile = fopen(tmpfile, "a");
 963        if (!packfile)
 964                return error("Unable to open local file %s for pack",
 965                             filename);
 966
 967        slot = get_active_slot();
 968        curl_easy_setopt(slot->curl, CURLOPT_FILE, packfile);
 969        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 970        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 971        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 972        slot->local = packfile;
 973
 974        /* If there is data present from a previous transfer attempt,
 975           resume where it left off */
 976        prev_posn = ftell(packfile);
 977        if (prev_posn>0) {
 978                if (get_verbosely)
 979                        fprintf(stderr,
 980                                "Resuming fetch of pack %s at byte %ld\n",
 981                                sha1_to_hex(target->sha1), prev_posn);
 982                sprintf(range, "Range: bytes=%ld-", prev_posn);
 983                range_header = curl_slist_append(range_header, range);
 984                curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 985        }
 986
 987        if (start_active_slot(slot)) {
 988                run_active_slot(slot);
 989                if (slot->curl_result != CURLE_OK) {
 990                        fclose(packfile);
 991                        return error("Unable to get pack file %s\n%s", url,
 992                                     curl_errorstr);
 993                }
 994        } else {
 995                return error("Unable to start request");
 996        }
 997
 998        fclose(packfile);
 999
1000        ret = move_temp_to_file(tmpfile, filename);
1001        if (ret)
1002                return ret;
1003
1004        lst = &repo->packs;
1005        while (*lst != target)
1006                lst = &((*lst)->next);
1007        *lst = (*lst)->next;
1008
1009        if (verify_pack(target, 0))
1010                return -1;
1011        install_packed_git(target);
1012
1013        return 0;
1014}
1015
1016static int fetch_object(struct alt_base *repo, unsigned char *sha1)
1017{
1018        char *hex = sha1_to_hex(sha1);
1019        int ret;
1020        struct transfer_request *request = request_queue_head;
1021
1022        while (request != NULL && memcmp(request->sha1, sha1, 20))
1023                request = request->next;
1024        if (request == NULL)
1025                return error("Couldn't find request for %s in the queue", hex);
1026
1027        if (has_sha1_file(request->sha1)) {
1028                release_request(request);
1029                return 0;
1030        }
1031
1032#ifdef USE_CURL_MULTI
1033        while (request->state == WAITING) {
1034                int num_transfers;
1035                curl_multi_perform(curlm, &num_transfers);
1036                if (num_transfers < active_requests) {
1037                        process_curl_messages();
1038                        process_request_queue();
1039                }
1040        }
1041#else
1042        start_request(request);
1043#endif
1044
1045        while (request->state == ACTIVE) {
1046                run_active_slot(request->slot);
1047#ifndef USE_CURL_MULTI
1048                request->curl_result = request->slot->curl_result;
1049                curl_easy_getinfo(request->slot->curl,
1050                                  CURLINFO_HTTP_CODE,
1051                                  &request->http_code);
1052                request->slot = NULL;
1053
1054                /* Use alternates if necessary */
1055                if (request->http_code == 404 &&
1056                    request->repo->next != NULL) {
1057                        request->repo = request->repo->next;
1058                        start_request(request);
1059                } else {
1060                        finish_request(request);
1061                        request->state = COMPLETE;
1062                }
1063#endif
1064        }
1065
1066        if (request->state == ABORTED) {
1067                release_request(request);
1068                return error("Request for %s aborted", hex);
1069        }
1070
1071        if (request->curl_result != CURLE_OK && request->http_code != 416) {
1072                ret = error("%s (curl_result = %d, http_code = %ld, sha1 = %s)",
1073                            request->errorstr, request->curl_result,
1074                            request->http_code, hex);
1075                release_request(request);
1076                return ret;
1077        }
1078
1079        if (request->zret != Z_STREAM_END) {
1080                ret = error("File %s (%s) corrupt\n", hex, request->url);
1081                release_request(request);
1082                return ret;
1083        }
1084
1085        if (memcmp(request->sha1, request->real_sha1, 20)) {
1086                release_request(request);
1087                return error("File %s has bad hash\n", hex);
1088        }
1089
1090        if (request->rename < 0) {
1091                ret = error("unable to write sha1 filename %s: %s",
1092                            request->filename,
1093                            strerror(request->rename));
1094                release_request(request);
1095                return ret;
1096        }
1097
1098        release_request(request);
1099        return 0;
1100}
1101
1102int fetch(unsigned char *sha1)
1103{
1104        struct alt_base *altbase = alt;
1105
1106        if (!fetch_object(altbase, sha1))
1107                return 0;
1108        while (altbase) {
1109                if (!fetch_pack(altbase, sha1))
1110                        return 0;
1111                altbase = altbase->next;
1112        }
1113        return error("Unable to find %s under %s\n", sha1_to_hex(sha1), 
1114                     alt->base);
1115}
1116
1117static inline int needs_quote(int ch)
1118{
1119        switch (ch) {
1120        case '/': case '-': case '.':
1121        case 'A'...'Z': case 'a'...'z': case '0'...'9':
1122                return 0;
1123        default:
1124                return 1;
1125        }
1126}
1127
1128static inline int hex(int v)
1129{
1130        if (v < 10) return '0' + v;
1131        else return 'A' + v - 10;
1132}
1133
1134static char *quote_ref_url(const char *base, const char *ref)
1135{
1136        const char *cp;
1137        char *dp, *qref;
1138        int len, baselen, ch;
1139
1140        baselen = strlen(base);
1141        len = baselen + 6; /* "refs/" + NUL */
1142        for (cp = ref; (ch = *cp) != 0; cp++, len++)
1143                if (needs_quote(ch))
1144                        len += 2; /* extra two hex plus replacement % */
1145        qref = xmalloc(len);
1146        memcpy(qref, base, baselen);
1147        memcpy(qref + baselen, "refs/", 5);
1148        for (cp = ref, dp = qref + baselen + 5; (ch = *cp) != 0; cp++) {
1149                if (needs_quote(ch)) {
1150                        *dp++ = '%';
1151                        *dp++ = hex((ch >> 4) & 0xF);
1152                        *dp++ = hex(ch & 0xF);
1153                }
1154                else
1155                        *dp++ = ch;
1156        }
1157        *dp = 0;
1158
1159        return qref;
1160}
1161
1162int fetch_ref(char *ref, unsigned char *sha1)
1163{
1164        char *url;
1165        char hex[42];
1166        struct buffer buffer;
1167        char *base = alt->base;
1168        struct active_request_slot *slot;
1169        buffer.size = 41;
1170        buffer.posn = 0;
1171        buffer.buffer = hex;
1172        hex[41] = '\0';
1173        
1174        url = quote_ref_url(base, ref);
1175        slot = get_active_slot();
1176        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
1177        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
1178        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
1179        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
1180        if (start_active_slot(slot)) {
1181                run_active_slot(slot);
1182                if (slot->curl_result != CURLE_OK)
1183                        return error("Couldn't get %s for %s\n%s",
1184                                     url, ref, curl_errorstr);
1185        } else {
1186                return error("Unable to start request");
1187        }
1188
1189        hex[40] = '\0';
1190        get_sha1_hex(hex, sha1);
1191        return 0;
1192}
1193
1194int main(int argc, char **argv)
1195{
1196        char *commit_id;
1197        char *url;
1198        int arg = 1;
1199        struct active_request_slot *slot;
1200        char *low_speed_limit;
1201        char *low_speed_time;
1202
1203        while (arg < argc && argv[arg][0] == '-') {
1204                if (argv[arg][1] == 't') {
1205                        get_tree = 1;
1206                } else if (argv[arg][1] == 'c') {
1207                        get_history = 1;
1208                } else if (argv[arg][1] == 'a') {
1209                        get_all = 1;
1210                        get_tree = 1;
1211                        get_history = 1;
1212                } else if (argv[arg][1] == 'v') {
1213                        get_verbosely = 1;
1214                } else if (argv[arg][1] == 'w') {
1215                        write_ref = argv[arg + 1];
1216                        arg++;
1217                } else if (!strcmp(argv[arg], "--recover")) {
1218                        get_recover = 1;
1219                }
1220                arg++;
1221        }
1222        if (argc < arg + 2) {
1223                usage("git-http-fetch [-c] [-t] [-a] [-d] [-v] [--recover] [-w ref] commit-id url");
1224                return 1;
1225        }
1226        commit_id = argv[arg];
1227        url = argv[arg + 1];
1228
1229        curl_global_init(CURL_GLOBAL_ALL);
1230
1231#ifdef USE_CURL_MULTI
1232        {
1233                char *http_max_requests = getenv("GIT_HTTP_MAX_REQUESTS");
1234                if (http_max_requests != NULL)
1235                        max_requests = atoi(http_max_requests);
1236        }
1237
1238        curlm = curl_multi_init();
1239        if (curlm == NULL) {
1240                fprintf(stderr, "Error creating curl multi handle.\n");
1241                return 1;
1242        }
1243#endif
1244
1245        if (getenv("GIT_SSL_NO_VERIFY"))
1246                curl_ssl_verify = 0;
1247
1248        ssl_cert = getenv("GIT_SSL_CERT");
1249#if LIBCURL_VERSION_NUM >= 0x070902
1250        ssl_key = getenv("GIT_SSL_KEY");
1251#endif
1252#if LIBCURL_VERSION_NUM >= 0x070908
1253        ssl_capath = getenv("GIT_SSL_CAPATH");
1254#endif
1255        ssl_cainfo = getenv("GIT_SSL_CAINFO");
1256
1257        low_speed_limit = getenv("GIT_HTTP_LOW_SPEED_LIMIT");
1258        if (low_speed_limit != NULL)
1259                curl_low_speed_limit = strtol(low_speed_limit, NULL, 10);
1260        low_speed_time = getenv("GIT_HTTP_LOW_SPEED_TIME");
1261        if (low_speed_time != NULL)
1262                curl_low_speed_time = strtol(low_speed_time, NULL, 10);
1263
1264        git_config(http_options);
1265
1266        if (curl_ssl_verify == -1)
1267                curl_ssl_verify = 1;
1268
1269#ifdef USE_CURL_MULTI
1270        if (max_requests < 1)
1271                max_requests = DEFAULT_MAX_REQUESTS;
1272#endif
1273
1274        pragma_header = curl_slist_append(pragma_header, "Pragma: no-cache");
1275        no_pragma_header = curl_slist_append(no_pragma_header, "Pragma:");
1276        no_range_header = curl_slist_append(no_range_header, "Range:");
1277
1278#ifndef NO_CURL_EASY_DUPHANDLE
1279        curl_default = get_curl_handle();
1280#endif
1281
1282        alt = xmalloc(sizeof(*alt));
1283        alt->base = url;
1284        alt->got_indices = 0;
1285        alt->packs = NULL;
1286        alt->next = NULL;
1287        fetch_alternates(alt->base);
1288
1289        if (pull(commit_id))
1290                return 1;
1291
1292        curl_slist_free_all(pragma_header);
1293        curl_slist_free_all(no_pragma_header);
1294        curl_slist_free_all(no_range_header);
1295#ifndef NO_CURL_EASY_DUPHANDLE
1296        curl_easy_cleanup(curl_default);
1297#endif
1298        slot = active_queue_head;
1299        while (slot != NULL) {
1300                curl_easy_cleanup(slot->curl);
1301                slot = slot->next;
1302        }
1303#ifdef USE_CURL_MULTI
1304        curl_multi_cleanup(curlm);
1305#endif
1306        curl_global_cleanup();
1307        return 0;
1308}