Andrew's git - gitweb.git/blob

5d0e3e3923c0399e9b4e650c2ee88368dff441ce
   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#define PREV_BUF_SIZE 4096
  22#define RANGE_HEADER_SIZE 30
  23
  24static int active_requests = 0;
  25static int data_received;
  26
  27#ifdef USE_CURL_MULTI
  28static int max_requests = DEFAULT_MAX_REQUESTS;
  29static CURLM *curlm;
  30#endif
  31static CURL *curl_default;
  32static struct curl_slist *pragma_header;
  33static struct curl_slist *no_pragma_header;
  34static struct curl_slist *no_range_header;
  35static char curl_errorstr[CURL_ERROR_SIZE];
  36
  37struct alt_base
  38{
  39        char *base;
  40        int got_indices;
  41        struct packed_git *packs;
  42        struct alt_base *next;
  43};
  44
  45static struct alt_base *alt = NULL;
  46
  47enum transfer_state {
  48        WAITING,
  49        ABORTED,
  50        ACTIVE,
  51        COMPLETE,
  52};
  53
  54struct transfer_request
  55{
  56        unsigned char sha1[20];
  57        struct alt_base *repo;
  58        char *url;
  59        char filename[PATH_MAX];
  60        char tmpfile[PATH_MAX];
  61        int local;
  62        enum transfer_state state;
  63        CURLcode curl_result;
  64        char errorstr[CURL_ERROR_SIZE];
  65        long http_code;
  66        unsigned char real_sha1[20];
  67        SHA_CTX c;
  68        z_stream stream;
  69        int zret;
  70        int rename;
  71        struct active_request_slot *slot;
  72        struct transfer_request *next;
  73};
  74
  75struct active_request_slot
  76{
  77        CURL *curl;
  78        FILE *local;
  79        int in_use;
  80        int done;
  81        CURLcode curl_result;
  82        struct active_request_slot *next;
  83};
  84
  85static struct transfer_request *request_queue_head = NULL;
  86static struct active_request_slot *active_queue_head = NULL;
  87
  88static int curl_ssl_verify;
  89static char *ssl_cert;
  90static char *ssl_key;
  91static char *ssl_capath;
  92static char *ssl_cainfo;
  93
  94struct buffer
  95{
  96        size_t posn;
  97        size_t size;
  98        void *buffer;
  99};
 100
 101static size_t fwrite_buffer(void *ptr, size_t eltsize, size_t nmemb,
 102                            struct buffer *buffer)
 103{
 104        size_t size = eltsize * nmemb;
 105        if (size > buffer->size - buffer->posn)
 106                size = buffer->size - buffer->posn;
 107        memcpy(buffer->buffer + buffer->posn, ptr, size);
 108        buffer->posn += size;
 109        data_received++;
 110        return size;
 111}
 112
 113static size_t fwrite_sha1_file(void *ptr, size_t eltsize, size_t nmemb,
 114                               void *data)
 115{
 116        unsigned char expn[4096];
 117        size_t size = eltsize * nmemb;
 118        int posn = 0;
 119        struct transfer_request *request = (struct transfer_request *)data;
 120        do {
 121                ssize_t retval = write(request->local,
 122                                       ptr + posn, size - posn);
 123                if (retval < 0)
 124                        return posn;
 125                posn += retval;
 126        } while (posn < size);
 127
 128        request->stream.avail_in = size;
 129        request->stream.next_in = ptr;
 130        do {
 131                request->stream.next_out = expn;
 132                request->stream.avail_out = sizeof(expn);
 133                request->zret = inflate(&request->stream, Z_SYNC_FLUSH);
 134                SHA1_Update(&request->c, expn,
 135                            sizeof(expn) - request->stream.avail_out);
 136        } while (request->stream.avail_in && request->zret == Z_OK);
 137        data_received++;
 138        return size;
 139}
 140
 141int relink_or_rename(char *old, char *new) {
 142        int ret;
 143
 144        ret = link(old, new);
 145        if (ret < 0) {
 146                /* Same Coda hack as in write_sha1_file(sha1_file.c) */
 147                ret = errno;
 148                if (ret == EXDEV && !rename(old, new))
 149                        return 0;
 150        }
 151        unlink(old);
 152        if (ret) {
 153                if (ret != EEXIST)
 154                        return ret;
 155        }
 156
 157        return 0;
 158}
 159
 160#ifdef USE_CURL_MULTI
 161void process_curl_messages();
 162void process_request_queue();
 163#endif
 164
 165struct active_request_slot *get_active_slot()
 166{
 167        struct active_request_slot *slot = active_queue_head;
 168        struct active_request_slot *newslot;
 169
 170#ifdef USE_CURL_MULTI
 171        int num_transfers;
 172
 173        /* Wait for a slot to open up if the queue is full */
 174        while (active_requests >= max_requests) {
 175                curl_multi_perform(curlm, &num_transfers);
 176                if (num_transfers < active_requests) {
 177                        process_curl_messages();
 178                }
 179        }
 180#endif
 181
 182        while (slot != NULL && slot->in_use) {
 183                slot = slot->next;
 184        }
 185        if (slot == NULL) {
 186                newslot = xmalloc(sizeof(*newslot));
 187                newslot->curl = curl_easy_duphandle(curl_default);
 188                newslot->in_use = 0;
 189                newslot->next = NULL;
 190
 191                slot = active_queue_head;
 192                if (slot == NULL) {
 193                        active_queue_head = newslot;
 194                } else {
 195                        while (slot->next != NULL) {
 196                                slot = slot->next;
 197                        }
 198                        slot->next = newslot;
 199                }
 200                slot = newslot;
 201        }
 202
 203        active_requests++;
 204        slot->in_use = 1;
 205        slot->done = 0;
 206        slot->local = NULL;
 207        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, pragma_header);
 208        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_range_header);
 209        curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, curl_errorstr);
 210
 211        return slot;
 212}
 213
 214int start_active_slot(struct active_request_slot *slot)
 215{
 216#ifdef USE_CURL_MULTI
 217        CURLMcode curlm_result = curl_multi_add_handle(curlm, slot->curl);
 218
 219        if (curlm_result != CURLM_OK &&
 220            curlm_result != CURLM_CALL_MULTI_PERFORM) {
 221                active_requests--;
 222                slot->in_use = 0;
 223                return 0;
 224        }
 225#endif
 226        return 1;
 227}
 228
 229void run_active_slot(struct active_request_slot *slot)
 230{
 231#ifdef USE_CURL_MULTI
 232        int num_transfers;
 233        long last_pos = 0;
 234        long current_pos;
 235        fd_set readfds;
 236        fd_set writefds;
 237        fd_set excfds;
 238        int max_fd;
 239        struct timeval select_timeout;
 240        CURLMcode curlm_result;
 241
 242        while (!slot->done) {
 243                data_received = 0;
 244                do {
 245                        curlm_result = curl_multi_perform(curlm,
 246                                                          &num_transfers);
 247                } while (curlm_result == CURLM_CALL_MULTI_PERFORM);
 248                if (num_transfers < active_requests) {
 249                        process_curl_messages();
 250                        process_request_queue();
 251                }
 252
 253                if (!data_received && slot->local != NULL) {
 254                        current_pos = ftell(slot->local);
 255                        if (current_pos > last_pos)
 256                                data_received++;
 257                        last_pos = current_pos;
 258                }
 259
 260                if (!slot->done && !data_received) {
 261                        max_fd = 0;
 262                        FD_ZERO(&readfds);
 263                        FD_ZERO(&writefds);
 264                        FD_ZERO(&excfds);
 265                        select_timeout.tv_sec = 0;
 266                        select_timeout.tv_usec = 50000;
 267                        select(max_fd, &readfds, &writefds,
 268                               &excfds, &select_timeout);
 269                }
 270        }
 271#else
 272        slot->curl_result = curl_easy_perform(slot->curl);
 273        active_requests--;
 274#endif
 275}
 276
 277void start_request(struct transfer_request *request)
 278{
 279        char *hex = sha1_to_hex(request->sha1);
 280        char prevfile[PATH_MAX];
 281        char *url;
 282        char *posn;
 283        int prevlocal;
 284        unsigned char prev_buf[PREV_BUF_SIZE];
 285        ssize_t prev_read = 0;
 286        long prev_posn = 0;
 287        char range[RANGE_HEADER_SIZE];
 288        struct curl_slist *range_header = NULL;
 289        struct active_request_slot *slot;
 290
 291        snprintf(prevfile, sizeof(prevfile), "%s.prev", request->filename);
 292        unlink(prevfile);
 293        rename(request->tmpfile, prevfile);
 294        unlink(request->tmpfile);
 295
 296        request->local = open(request->tmpfile,
 297                              O_WRONLY | O_CREAT | O_EXCL, 0666);
 298        if (request->local < 0) {
 299                request->state = ABORTED;
 300                error("Couldn't create temporary file %s for %s: %s\n",
 301                      request->tmpfile, request->filename, strerror(errno));
 302                return;
 303        }
 304
 305        memset(&request->stream, 0, sizeof(request->stream));
 306
 307        inflateInit(&request->stream);
 308
 309        SHA1_Init(&request->c);
 310
 311        url = xmalloc(strlen(request->repo->base) + 50);
 312        request->url = xmalloc(strlen(request->repo->base) + 50);
 313        strcpy(url, request->repo->base);
 314        posn = url + strlen(request->repo->base);
 315        strcpy(posn, "objects/");
 316        posn += 8;
 317        memcpy(posn, hex, 2);
 318        posn += 2;
 319        *(posn++) = '/';
 320        strcpy(posn, hex + 2);
 321        strcpy(request->url, url);
 322
 323        /* If a previous temp file is present, process what was already
 324           fetched. */
 325        prevlocal = open(prevfile, O_RDONLY);
 326        if (prevlocal != -1) {
 327                do {
 328                        prev_read = read(prevlocal, prev_buf, PREV_BUF_SIZE);
 329                        if (prev_read>0) {
 330                                if (fwrite_sha1_file(prev_buf,
 331                                                     1,
 332                                                     prev_read,
 333                                                     request) == prev_read) {
 334                                        prev_posn += prev_read;
 335                                } else {
 336                                        prev_read = -1;
 337                                }
 338                        }
 339                } while (prev_read > 0);
 340                close(prevlocal);
 341        }
 342        unlink(prevfile);
 343
 344        /* Reset inflate/SHA1 if there was an error reading the previous temp
 345           file; also rewind to the beginning of the local file. */
 346        if (prev_read == -1) {
 347                memset(&request->stream, 0, sizeof(request->stream));
 348                inflateInit(&request->stream);
 349                SHA1_Init(&request->c);
 350                if (prev_posn>0) {
 351                        prev_posn = 0;
 352                        lseek(request->local, SEEK_SET, 0);
 353                        ftruncate(request->local, 0);
 354                }
 355        }
 356
 357        slot = get_active_slot();
 358        curl_easy_setopt(slot->curl, CURLOPT_FILE, request);
 359        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);
 360        curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, request->errorstr);
 361        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 362        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 363
 364        /* If we have successfully processed data from a previous fetch
 365           attempt, only fetch the data we don't already have. */
 366        if (prev_posn>0) {
 367                if (get_verbosely)
 368                        fprintf(stderr,
 369                                "Resuming fetch of object %s at byte %ld\n",
 370                                hex, prev_posn);
 371                sprintf(range, "Range: bytes=%ld-", prev_posn);
 372                range_header = curl_slist_append(range_header, range);
 373                curl_easy_setopt(slot->curl,
 374                                 CURLOPT_HTTPHEADER, range_header);
 375        }
 376
 377        /* Try to get the request started, abort the request on error */
 378        if (!start_active_slot(slot)) {
 379                request->state = ABORTED;
 380                close(request->local);
 381                free(request->url);
 382                return;
 383        }
 384        
 385        request->slot = slot;
 386        request->state = ACTIVE;
 387}
 388
 389void finish_request(struct transfer_request *request)
 390{
 391        fchmod(request->local, 0444);
 392        close(request->local);
 393
 394        if (request->http_code == 416) {
 395                fprintf(stderr, "Warning: requested range invalid; we may already have all the data.\n");
 396        } else if (request->curl_result != CURLE_OK) {
 397                return;
 398        }
 399
 400        inflateEnd(&request->stream);
 401        SHA1_Final(request->real_sha1, &request->c);
 402        if (request->zret != Z_STREAM_END) {
 403                unlink(request->tmpfile);
 404                return;
 405        }
 406        if (memcmp(request->sha1, request->real_sha1, 20)) {
 407                unlink(request->tmpfile);
 408                return;
 409        }
 410        request->rename =
 411                relink_or_rename(request->tmpfile, request->filename);
 412
 413        if (request->rename == 0)
 414                pull_say("got %s\n", sha1_to_hex(request->sha1));
 415}
 416
 417void release_request(struct transfer_request *request)
 418{
 419        struct transfer_request *entry = request_queue_head;
 420
 421        if (request == request_queue_head) {
 422                request_queue_head = request->next;
 423        } else {
 424                while (entry->next != NULL && entry->next != request)
 425                        entry = entry->next;
 426                if (entry->next == request)
 427                        entry->next = entry->next->next;
 428        }
 429
 430        free(request->url);
 431        free(request);
 432}
 433
 434#ifdef USE_CURL_MULTI
 435void process_curl_messages()
 436{
 437        int num_messages;
 438        struct active_request_slot *slot;
 439        struct transfer_request *request = NULL;
 440        CURLMsg *curl_message = curl_multi_info_read(curlm, &num_messages);
 441
 442        while (curl_message != NULL) {
 443                if (curl_message->msg == CURLMSG_DONE) {
 444                        slot = active_queue_head;
 445                        while (slot != NULL &&
 446                               slot->curl != curl_message->easy_handle)
 447                                slot = slot->next;
 448                        if (slot != NULL) {
 449                                curl_multi_remove_handle(curlm, slot->curl);
 450                                active_requests--;
 451                                slot->done = 1;
 452                                slot->in_use = 0;
 453                                slot->curl_result = curl_message->data.result;
 454                                request = request_queue_head;
 455                                while (request != NULL &&
 456                                       request->slot != slot)
 457                                        request = request->next;
 458                        } else {
 459                                fprintf(stderr, "Received DONE message for unknown request!\n");
 460                        }
 461                        if (request != NULL) {
 462                                request->curl_result =
 463                                        curl_message->data.result;
 464                                curl_easy_getinfo(slot->curl,
 465                                                  CURLINFO_HTTP_CODE,
 466                                                  &request->http_code);
 467                                request->slot = NULL;
 468
 469                                /* Use alternates if necessary */
 470                                if (request->http_code == 404 &&
 471                                    request->repo->next != NULL) {
 472                                        request->repo = request->repo->next;
 473                                        start_request(request);
 474                                } else {
 475                                        finish_request(request);
 476                                        request->state = COMPLETE;
 477                                }
 478                        }
 479                } else {
 480                        fprintf(stderr, "Unknown CURL message received: %d\n",
 481                                (int)curl_message->msg);
 482                }
 483                curl_message = curl_multi_info_read(curlm, &num_messages);
 484        }
 485}
 486
 487void process_request_queue()
 488{
 489        struct transfer_request *request = request_queue_head;
 490        int num_transfers;
 491
 492        while (active_requests < max_requests && request != NULL) {
 493                if (request->state == WAITING) {
 494                        if (has_sha1_file(request->sha1))
 495                                release_request(request);
 496                        else
 497                                start_request(request);
 498                        curl_multi_perform(curlm, &num_transfers);
 499                }
 500                request = request->next;
 501        }
 502}
 503#endif
 504
 505void prefetch(unsigned char *sha1)
 506{
 507        struct transfer_request *newreq;
 508        struct transfer_request *tail;
 509        char *filename = sha1_file_name(sha1);
 510
 511        newreq = xmalloc(sizeof(*newreq));
 512        memcpy(newreq->sha1, sha1, 20);
 513        newreq->repo = alt;
 514        newreq->url = NULL;
 515        newreq->local = -1;
 516        newreq->state = WAITING;
 517        snprintf(newreq->filename, sizeof(newreq->filename), "%s", filename);
 518        snprintf(newreq->tmpfile, sizeof(newreq->tmpfile),
 519                 "%s.temp", filename);
 520        newreq->next = NULL;
 521
 522        if (request_queue_head == NULL) {
 523                request_queue_head = newreq;
 524        } else {
 525                tail = request_queue_head;
 526                while (tail->next != NULL) {
 527                        tail = tail->next;
 528                }
 529                tail->next = newreq;
 530        }
 531#ifdef USE_CURL_MULTI
 532        process_request_queue();
 533        process_curl_messages();
 534#endif
 535}
 536
 537static int got_alternates = 0;
 538
 539static int fetch_index(struct alt_base *repo, unsigned char *sha1)
 540{
 541        char *hex = sha1_to_hex(sha1);
 542        char *filename;
 543        char *url;
 544        char tmpfile[PATH_MAX];
 545        int ret;
 546        long prev_posn = 0;
 547        char range[RANGE_HEADER_SIZE];
 548        struct curl_slist *range_header = NULL;
 549
 550        FILE *indexfile;
 551        struct active_request_slot *slot;
 552
 553        if (has_pack_index(sha1))
 554                return 0;
 555
 556        if (get_verbosely)
 557                fprintf(stderr, "Getting index for pack %s\n", hex);
 558        
 559        url = xmalloc(strlen(repo->base) + 64);
 560        sprintf(url, "%s/objects/pack/pack-%s.idx", repo->base, hex);
 561        
 562        filename = sha1_pack_index_name(sha1);
 563        snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 564        indexfile = fopen(tmpfile, "a");
 565        if (!indexfile)
 566                return error("Unable to open local file %s for pack index",
 567                             filename);
 568
 569        slot = get_active_slot();
 570        curl_easy_setopt(slot->curl, CURLOPT_FILE, indexfile);
 571        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 572        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 573        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 574        slot->local = indexfile;
 575
 576        /* If there is data present from a previous transfer attempt,
 577           resume where it left off */
 578        prev_posn = ftell(indexfile);
 579        if (prev_posn>0) {
 580                if (get_verbosely)
 581                        fprintf(stderr,
 582                                "Resuming fetch of index for pack %s at byte %ld\n",
 583                                hex, prev_posn);
 584                sprintf(range, "Range: bytes=%ld-", prev_posn);
 585                range_header = curl_slist_append(range_header, range);
 586                curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 587        }
 588
 589        if (start_active_slot(slot)) {
 590                run_active_slot(slot);
 591                if (slot->curl_result != CURLE_OK) {
 592                        fclose(indexfile);
 593                        return error("Unable to get pack index %s\n%s", url,
 594                                     curl_errorstr);
 595                }
 596        } else {
 597                return error("Unable to start request");
 598        }
 599
 600        fclose(indexfile);
 601
 602        ret = relink_or_rename(tmpfile, filename);
 603        if (ret)
 604                return error("unable to write index filename %s: %s",
 605                             filename, strerror(ret));
 606
 607        return 0;
 608}
 609
 610static int setup_index(struct alt_base *repo, unsigned char *sha1)
 611{
 612        struct packed_git *new_pack;
 613        if (has_pack_file(sha1))
 614                return 0; // don't list this as something we can get
 615
 616        if (fetch_index(repo, sha1))
 617                return -1;
 618
 619        new_pack = parse_pack_index(sha1);
 620        new_pack->next = repo->packs;
 621        repo->packs = new_pack;
 622        return 0;
 623}
 624
 625static int fetch_alternates(char *base)
 626{
 627        int ret = 0;
 628        struct buffer buffer;
 629        char *url;
 630        char *data;
 631        int i = 0;
 632        int http_specific = 1;
 633        struct alt_base *tail = alt;
 634
 635        struct active_request_slot *slot;
 636        if (got_alternates)
 637                return 0;
 638        data = xmalloc(4096);
 639        buffer.size = 4095;
 640        buffer.posn = 0;
 641        buffer.buffer = data;
 642
 643        if (get_verbosely)
 644                fprintf(stderr, "Getting alternates list\n");
 645        
 646        url = xmalloc(strlen(base) + 31);
 647        sprintf(url, "%s/objects/info/http-alternates", base);
 648
 649        slot = get_active_slot();
 650        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 651        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 652        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 653        if (start_active_slot(slot)) {
 654                run_active_slot(slot);
 655                if (slot->curl_result != CURLE_OK || !buffer.posn) {
 656                        http_specific = 0;
 657
 658                        sprintf(url, "%s/objects/info/alternates", base);
 659
 660                        slot = get_active_slot();
 661                        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 662                        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
 663                                         fwrite_buffer);
 664                        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 665                        if (start_active_slot(slot)) {
 666                                run_active_slot(slot);
 667                                if (slot->curl_result != CURLE_OK) {
 668                                        return 0;
 669                                }
 670                        }
 671                }
 672        } else {
 673                return 0;
 674        }
 675
 676        data[buffer.posn] = '\0';
 677
 678        while (i < buffer.posn) {
 679                int posn = i;
 680                while (posn < buffer.posn && data[posn] != '\n')
 681                        posn++;
 682                if (data[posn] == '\n') {
 683                        int okay = 0;
 684                        int serverlen = 0;
 685                        struct alt_base *newalt;
 686                        char *target = NULL;
 687                        if (data[i] == '/') {
 688                                serverlen = strchr(base + 8, '/') - base;
 689                                okay = 1;
 690                        } else if (!memcmp(data + i, "../", 3)) {
 691                                i += 3;
 692                                serverlen = strlen(base);
 693                                while (i + 2 < posn && 
 694                                       !memcmp(data + i, "../", 3)) {
 695                                        do {
 696                                                serverlen--;
 697                                        } while (serverlen &&
 698                                                 base[serverlen - 1] != '/');
 699                                        i += 3;
 700                                }
 701                                // If the server got removed, give up.
 702                                okay = strchr(base, ':') - base + 3 < 
 703                                        serverlen;
 704                        } else if (http_specific) {
 705                                char *colon = strchr(data + i, ':');
 706                                char *slash = strchr(data + i, '/');
 707                                if (colon && slash && colon < data + posn &&
 708                                    slash < data + posn && colon < slash) {
 709                                        okay = 1;
 710                                }
 711                        }
 712                        // skip 'objects' at end
 713                        if (okay) {
 714                                target = xmalloc(serverlen + posn - i - 6);
 715                                strncpy(target, base, serverlen);
 716                                strncpy(target + serverlen, data + i,
 717                                        posn - i - 7);
 718                                target[serverlen + posn - i - 7] = '\0';
 719                                if (get_verbosely)
 720                                        fprintf(stderr, 
 721                                                "Also look at %s\n", target);
 722                                newalt = xmalloc(sizeof(*newalt));
 723                                newalt->next = NULL;
 724                                newalt->base = target;
 725                                newalt->got_indices = 0;
 726                                newalt->packs = NULL;
 727                                while (tail->next != NULL)
 728                                        tail = tail->next;
 729                                tail->next = newalt;
 730                                ret++;
 731                        }
 732                }
 733                i = posn + 1;
 734        }
 735        got_alternates = 1;
 736        
 737        return ret;
 738}
 739
 740static int fetch_indices(struct alt_base *repo)
 741{
 742        unsigned char sha1[20];
 743        char *url;
 744        struct buffer buffer;
 745        char *data;
 746        int i = 0;
 747
 748        struct active_request_slot *slot;
 749
 750        if (repo->got_indices)
 751                return 0;
 752
 753        data = xmalloc(4096);
 754        buffer.size = 4096;
 755        buffer.posn = 0;
 756        buffer.buffer = data;
 757
 758        if (get_verbosely)
 759                fprintf(stderr, "Getting pack list\n");
 760        
 761        url = xmalloc(strlen(repo->base) + 21);
 762        sprintf(url, "%s/objects/info/packs", repo->base);
 763
 764        slot = get_active_slot();
 765        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 766        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 767        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 768        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 769        if (start_active_slot(slot)) {
 770                run_active_slot(slot);
 771                if (slot->curl_result != CURLE_OK)
 772                        return error("%s", curl_errorstr);
 773        } else {
 774                return error("Unable to start request");
 775        }
 776
 777        while (i < buffer.posn) {
 778                switch (data[i]) {
 779                case 'P':
 780                        i++;
 781                        if (i + 52 < buffer.posn &&
 782                            !strncmp(data + i, " pack-", 6) &&
 783                            !strncmp(data + i + 46, ".pack\n", 6)) {
 784                                get_sha1_hex(data + i + 6, sha1);
 785                                setup_index(repo, sha1);
 786                                i += 51;
 787                                break;
 788                        }
 789                default:
 790                        while (data[i] != '\n')
 791                                i++;
 792                }
 793                i++;
 794        }
 795
 796        repo->got_indices = 1;
 797        return 0;
 798}
 799
 800static int fetch_pack(struct alt_base *repo, unsigned char *sha1)
 801{
 802        char *url;
 803        struct packed_git *target;
 804        struct packed_git **lst;
 805        FILE *packfile;
 806        char *filename;
 807        char tmpfile[PATH_MAX];
 808        int ret;
 809        long prev_posn = 0;
 810        char range[RANGE_HEADER_SIZE];
 811        struct curl_slist *range_header = NULL;
 812
 813        struct active_request_slot *slot;
 814
 815        if (fetch_indices(repo))
 816                return -1;
 817        target = find_sha1_pack(sha1, repo->packs);
 818        if (!target)
 819                return -1;
 820
 821        if (get_verbosely) {
 822                fprintf(stderr, "Getting pack %s\n",
 823                        sha1_to_hex(target->sha1));
 824                fprintf(stderr, " which contains %s\n",
 825                        sha1_to_hex(sha1));
 826        }
 827
 828        url = xmalloc(strlen(repo->base) + 65);
 829        sprintf(url, "%s/objects/pack/pack-%s.pack",
 830                repo->base, sha1_to_hex(target->sha1));
 831
 832        filename = sha1_pack_name(target->sha1);
 833        snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 834        packfile = fopen(tmpfile, "a");
 835        if (!packfile)
 836                return error("Unable to open local file %s for pack",
 837                             filename);
 838
 839        slot = get_active_slot();
 840        curl_easy_setopt(slot->curl, CURLOPT_FILE, packfile);
 841        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 842        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 843        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 844        slot->local = packfile;
 845
 846        /* If there is data present from a previous transfer attempt,
 847           resume where it left off */
 848        prev_posn = ftell(packfile);
 849        if (prev_posn>0) {
 850                if (get_verbosely)
 851                        fprintf(stderr,
 852                                "Resuming fetch of pack %s at byte %ld\n",
 853                                sha1_to_hex(target->sha1), prev_posn);
 854                sprintf(range, "Range: bytes=%ld-", prev_posn);
 855                range_header = curl_slist_append(range_header, range);
 856                curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 857        }
 858
 859        if (start_active_slot(slot)) {
 860                run_active_slot(slot);
 861                if (slot->curl_result != CURLE_OK) {
 862                        fclose(packfile);
 863                        return error("Unable to get pack file %s\n%s", url,
 864                                     curl_errorstr);
 865                }
 866        } else {
 867                return error("Unable to start request");
 868        }
 869
 870        fclose(packfile);
 871
 872        ret = relink_or_rename(tmpfile, filename);
 873        if (ret)
 874                return error("unable to write pack filename %s: %s",
 875                             filename, strerror(ret));
 876
 877        lst = &repo->packs;
 878        while (*lst != target)
 879                lst = &((*lst)->next);
 880        *lst = (*lst)->next;
 881
 882        if (verify_pack(target, 0))
 883                return -1;
 884        install_packed_git(target);
 885
 886        return 0;
 887}
 888
 889static int fetch_object(struct alt_base *repo, unsigned char *sha1)
 890{
 891        char *hex = sha1_to_hex(sha1);
 892        int ret;
 893        struct transfer_request *request = request_queue_head;
 894
 895        while (request != NULL && memcmp(request->sha1, sha1, 20))
 896                request = request->next;
 897        if (request == NULL)
 898                return error("Couldn't find request for %s in the queue", hex);
 899
 900        if (has_sha1_file(request->sha1)) {
 901                release_request(request);
 902                return 0;
 903        }
 904
 905#ifdef USE_CURL_MULTI
 906        int num_transfers;
 907        while (request->state == WAITING) {
 908                curl_multi_perform(curlm, &num_transfers);
 909                if (num_transfers < active_requests) {
 910                        process_curl_messages();
 911                        process_request_queue();
 912                }
 913        }
 914#else
 915        start_request(request);
 916#endif
 917
 918        while (request->state == ACTIVE) {
 919                run_active_slot(request->slot);
 920#ifndef USE_CURL_MULTI
 921                request->curl_result = request->slot->curl_result;
 922                curl_easy_getinfo(request->slot->curl,
 923                                  CURLINFO_HTTP_CODE,
 924                                  &request->http_code);
 925                request->slot = NULL;
 926
 927                /* Use alternates if necessary */
 928                if (request->http_code == 404 &&
 929                    request->repo->next != NULL) {
 930                        request->repo = request->repo->next;
 931                        start_request(request);
 932                } else {
 933                        finish_request(request);
 934                        request->state = COMPLETE;
 935                }
 936#endif
 937        }
 938
 939        if (request->state == ABORTED) {
 940                release_request(request);
 941                return error("Request for %s aborted", hex);
 942        }
 943
 944        if (request->curl_result != CURLE_OK && request->http_code != 416) {
 945                ret = error("%s", request->errorstr);
 946                release_request(request);
 947                return ret;
 948        }
 949
 950        if (request->zret != Z_STREAM_END) {
 951                ret = error("File %s (%s) corrupt\n", hex, request->url);
 952                release_request(request);
 953                return ret;
 954        }
 955
 956        if (memcmp(request->sha1, request->real_sha1, 20)) {
 957                release_request(request);
 958                return error("File %s has bad hash\n", hex);
 959        }
 960
 961        if (request->rename < 0) {
 962                ret = error("unable to write sha1 filename %s: %s",
 963                            request->filename,
 964                            strerror(request->rename));
 965                release_request(request);
 966                return ret;
 967        }
 968
 969        release_request(request);
 970        return 0;
 971}
 972
 973int fetch(unsigned char *sha1)
 974{
 975        struct alt_base *altbase = alt;
 976
 977        if (!fetch_object(altbase, sha1))
 978                return 0;
 979        while (altbase) {
 980                if (!fetch_pack(altbase, sha1))
 981                        return 0;
 982                altbase = altbase->next;
 983        }
 984        return error("Unable to find %s under %s\n", sha1_to_hex(sha1), 
 985                     alt->base);
 986}
 987
 988int fetch_ref(char *ref, unsigned char *sha1)
 989{
 990        char *url, *posn;
 991        char hex[42];
 992        struct buffer buffer;
 993        char *base = alt->base;
 994        struct active_request_slot *slot;
 995        buffer.size = 41;
 996        buffer.posn = 0;
 997        buffer.buffer = hex;
 998        hex[41] = '\0';
 999        
1000        url = xmalloc(strlen(base) + 6 + strlen(ref));
1001        strcpy(url, base);
1002        posn = url + strlen(base);
1003        strcpy(posn, "refs/");
1004        posn += 5;
1005        strcpy(posn, ref);
1006
1007        slot = get_active_slot();
1008        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
1009        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
1010        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
1011        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
1012        if (start_active_slot(slot)) {
1013                run_active_slot(slot);
1014                if (slot->curl_result != CURLE_OK)
1015                        return error("Couldn't get %s for %s\n%s",
1016                                     url, ref, curl_errorstr);
1017        } else {
1018                return error("Unable to start request");
1019        }
1020
1021        hex[40] = '\0';
1022        get_sha1_hex(hex, sha1);
1023        return 0;
1024}
1025
1026int main(int argc, char **argv)
1027{
1028        char *commit_id;
1029        char *url;
1030        int arg = 1;
1031        struct active_request_slot *slot;
1032
1033        while (arg < argc && argv[arg][0] == '-') {
1034                if (argv[arg][1] == 't') {
1035                        get_tree = 1;
1036                } else if (argv[arg][1] == 'c') {
1037                        get_history = 1;
1038                } else if (argv[arg][1] == 'a') {
1039                        get_all = 1;
1040                        get_tree = 1;
1041                        get_history = 1;
1042                } else if (argv[arg][1] == 'v') {
1043                        get_verbosely = 1;
1044                } else if (argv[arg][1] == 'w') {
1045                        write_ref = argv[arg + 1];
1046                        arg++;
1047                } else if (!strcmp(argv[arg], "--recover")) {
1048                        get_recover = 1;
1049                }
1050                arg++;
1051        }
1052        if (argc < arg + 2) {
1053                usage("git-http-fetch [-c] [-t] [-a] [-d] [-v] [--recover] [-w ref] commit-id url");
1054                return 1;
1055        }
1056        commit_id = argv[arg];
1057        url = argv[arg + 1];
1058
1059        curl_global_init(CURL_GLOBAL_ALL);
1060
1061#ifdef USE_CURL_MULTI
1062        char *http_max_requests = getenv("GIT_HTTP_MAX_REQUESTS");
1063        if (http_max_requests != NULL)
1064                max_requests = atoi(http_max_requests);
1065        if (max_requests < 1)
1066                max_requests = DEFAULT_MAX_REQUESTS;
1067
1068        curlm = curl_multi_init();
1069        if (curlm == NULL) {
1070                fprintf(stderr, "Error creating curl multi handle.\n");
1071                return 1;
1072        }
1073#endif
1074        pragma_header = curl_slist_append(pragma_header, "Pragma: no-cache");
1075        no_pragma_header = curl_slist_append(no_pragma_header, "Pragma:");
1076        no_range_header = curl_slist_append(no_range_header, "Range:");
1077
1078        curl_default = curl_easy_init();
1079
1080        curl_ssl_verify = getenv("GIT_SSL_NO_VERIFY") ? 0 : 1;
1081        curl_easy_setopt(curl_default, CURLOPT_SSL_VERIFYPEER, curl_ssl_verify);
1082#if LIBCURL_VERSION_NUM >= 0x070907
1083        curl_easy_setopt(curl_default, CURLOPT_NETRC, CURL_NETRC_OPTIONAL);
1084#endif
1085
1086        if ((ssl_cert = getenv("GIT_SSL_CERT")) != NULL) {
1087                curl_easy_setopt(curl_default, CURLOPT_SSLCERT, ssl_cert);
1088        }
1089#if LIBCURL_VERSION_NUM >= 0x070902
1090        if ((ssl_key = getenv("GIT_SSL_KEY")) != NULL) {
1091                curl_easy_setopt(curl_default, CURLOPT_SSLKEY, ssl_key);
1092        }
1093#endif
1094#if LIBCURL_VERSION_NUM >= 0x070908
1095        if ((ssl_capath = getenv("GIT_SSL_CAPATH")) != NULL) {
1096                curl_easy_setopt(curl_default, CURLOPT_CAPATH, ssl_capath);
1097        }
1098#endif
1099        if ((ssl_cainfo = getenv("GIT_SSL_CAINFO")) != NULL) {
1100                curl_easy_setopt(curl_default, CURLOPT_CAINFO, ssl_cainfo);
1101        }
1102        curl_easy_setopt(curl_default, CURLOPT_FAILONERROR, 1);
1103
1104        alt = xmalloc(sizeof(*alt));
1105        alt->base = url;
1106        alt->got_indices = 0;
1107        alt->packs = NULL;
1108        alt->next = NULL;
1109        fetch_alternates(alt->base);
1110
1111        if (pull(commit_id))
1112                return 1;
1113
1114        curl_slist_free_all(pragma_header);
1115        curl_slist_free_all(no_pragma_header);
1116        curl_slist_free_all(no_range_header);
1117        curl_easy_cleanup(curl_default);
1118        slot = active_queue_head;
1119        while (slot != NULL) {
1120                curl_easy_cleanup(slot->curl);
1121                slot = slot->next;
1122        }
1123#ifdef USE_CURL_MULTI
1124        curl_multi_cleanup(curlm);
1125#endif
1126        curl_global_cleanup();
1127        return 0;
1128}