Andrew's git - gitweb.git/blob

c6daf6a01f3dd47059641495e8afb84f1d752b2a
   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_buffer_dynamic(const void *ptr, size_t eltsize,
 114                                    size_t nmemb, struct buffer *buffer)
 115{
 116        size_t size = eltsize * nmemb;
 117        if (size > buffer->size - buffer->posn) {
 118                buffer->size = buffer->size * 3 / 2;
 119                if (buffer->size < buffer->posn + size)
 120                        buffer->size = buffer->posn + size;
 121                buffer->buffer = xrealloc(buffer->buffer, buffer->size);
 122        }
 123        memcpy(buffer->buffer + buffer->posn, ptr, size);
 124        buffer->posn += size;
 125        data_received++;
 126        return size;
 127}
 128
 129static size_t fwrite_sha1_file(void *ptr, size_t eltsize, size_t nmemb,
 130                               void *data)
 131{
 132        unsigned char expn[4096];
 133        size_t size = eltsize * nmemb;
 134        int posn = 0;
 135        struct transfer_request *request = (struct transfer_request *)data;
 136        do {
 137                ssize_t retval = write(request->local,
 138                                       ptr + posn, size - posn);
 139                if (retval < 0)
 140                        return posn;
 141                posn += retval;
 142        } while (posn < size);
 143
 144        request->stream.avail_in = size;
 145        request->stream.next_in = ptr;
 146        do {
 147                request->stream.next_out = expn;
 148                request->stream.avail_out = sizeof(expn);
 149                request->zret = inflate(&request->stream, Z_SYNC_FLUSH);
 150                SHA1_Update(&request->c, expn,
 151                            sizeof(expn) - request->stream.avail_out);
 152        } while (request->stream.avail_in && request->zret == Z_OK);
 153        data_received++;
 154        return size;
 155}
 156
 157#ifdef USE_CURL_MULTI
 158void process_curl_messages();
 159void process_request_queue();
 160#endif
 161
 162struct active_request_slot *get_active_slot()
 163{
 164        struct active_request_slot *slot = active_queue_head;
 165        struct active_request_slot *newslot;
 166
 167#ifdef USE_CURL_MULTI
 168        int num_transfers;
 169
 170        /* Wait for a slot to open up if the queue is full */
 171        while (active_requests >= max_requests) {
 172                curl_multi_perform(curlm, &num_transfers);
 173                if (num_transfers < active_requests) {
 174                        process_curl_messages();
 175                }
 176        }
 177#endif
 178
 179        while (slot != NULL && slot->in_use) {
 180                slot = slot->next;
 181        }
 182        if (slot == NULL) {
 183                newslot = xmalloc(sizeof(*newslot));
 184                newslot->curl = curl_easy_duphandle(curl_default);
 185                newslot->in_use = 0;
 186                newslot->next = NULL;
 187
 188                slot = active_queue_head;
 189                if (slot == NULL) {
 190                        active_queue_head = newslot;
 191                } else {
 192                        while (slot->next != NULL) {
 193                                slot = slot->next;
 194                        }
 195                        slot->next = newslot;
 196                }
 197                slot = newslot;
 198        }
 199
 200        active_requests++;
 201        slot->in_use = 1;
 202        slot->done = 0;
 203        slot->local = NULL;
 204        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, pragma_header);
 205        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_range_header);
 206        curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, curl_errorstr);
 207
 208        return slot;
 209}
 210
 211int start_active_slot(struct active_request_slot *slot)
 212{
 213#ifdef USE_CURL_MULTI
 214        CURLMcode curlm_result = curl_multi_add_handle(curlm, slot->curl);
 215
 216        if (curlm_result != CURLM_OK &&
 217            curlm_result != CURLM_CALL_MULTI_PERFORM) {
 218                active_requests--;
 219                slot->in_use = 0;
 220                return 0;
 221        }
 222#endif
 223        return 1;
 224}
 225
 226void run_active_slot(struct active_request_slot *slot)
 227{
 228#ifdef USE_CURL_MULTI
 229        int num_transfers;
 230        long last_pos = 0;
 231        long current_pos;
 232        fd_set readfds;
 233        fd_set writefds;
 234        fd_set excfds;
 235        int max_fd;
 236        struct timeval select_timeout;
 237        CURLMcode curlm_result;
 238
 239        while (!slot->done) {
 240                data_received = 0;
 241                do {
 242                        curlm_result = curl_multi_perform(curlm,
 243                                                          &num_transfers);
 244                } while (curlm_result == CURLM_CALL_MULTI_PERFORM);
 245                if (num_transfers < active_requests) {
 246                        process_curl_messages();
 247                        process_request_queue();
 248                }
 249
 250                if (!data_received && slot->local != NULL) {
 251                        current_pos = ftell(slot->local);
 252                        if (current_pos > last_pos)
 253                                data_received++;
 254                        last_pos = current_pos;
 255                }
 256
 257                if (!slot->done && !data_received) {
 258                        max_fd = 0;
 259                        FD_ZERO(&readfds);
 260                        FD_ZERO(&writefds);
 261                        FD_ZERO(&excfds);
 262                        select_timeout.tv_sec = 0;
 263                        select_timeout.tv_usec = 50000;
 264                        select(max_fd, &readfds, &writefds,
 265                               &excfds, &select_timeout);
 266                }
 267        }
 268#else
 269        slot->curl_result = curl_easy_perform(slot->curl);
 270        active_requests--;
 271#endif
 272}
 273
 274void start_request(struct transfer_request *request)
 275{
 276        char *hex = sha1_to_hex(request->sha1);
 277        char prevfile[PATH_MAX];
 278        char *url;
 279        char *posn;
 280        int prevlocal;
 281        unsigned char prev_buf[PREV_BUF_SIZE];
 282        ssize_t prev_read = 0;
 283        long prev_posn = 0;
 284        char range[RANGE_HEADER_SIZE];
 285        struct curl_slist *range_header = NULL;
 286        struct active_request_slot *slot;
 287
 288        snprintf(prevfile, sizeof(prevfile), "%s.prev", request->filename);
 289        unlink(prevfile);
 290        rename(request->tmpfile, prevfile);
 291        unlink(request->tmpfile);
 292
 293        request->local = open(request->tmpfile,
 294                              O_WRONLY | O_CREAT | O_EXCL, 0666);
 295        /* This could have failed due to the "lazy directory creation";
 296         * try to mkdir the last path component.
 297         */
 298        if (request->local < 0 && errno == ENOENT) {
 299                char *dir = strrchr(request->tmpfile, '/');
 300                if (dir) {
 301                        *dir = 0;
 302                        mkdir(request->tmpfile, 0777);
 303                        *dir = '/';
 304                }
 305                request->local = open(request->tmpfile,
 306                                      O_WRONLY | O_CREAT | O_EXCL, 0666);
 307        }
 308
 309        if (request->local < 0) {
 310                request->state = ABORTED;
 311                error("Couldn't create temporary file %s for %s: %s\n",
 312                      request->tmpfile, request->filename, strerror(errno));
 313                return;
 314        }
 315
 316        memset(&request->stream, 0, sizeof(request->stream));
 317
 318        inflateInit(&request->stream);
 319
 320        SHA1_Init(&request->c);
 321
 322        url = xmalloc(strlen(request->repo->base) + 50);
 323        request->url = xmalloc(strlen(request->repo->base) + 50);
 324        strcpy(url, request->repo->base);
 325        posn = url + strlen(request->repo->base);
 326        strcpy(posn, "objects/");
 327        posn += 8;
 328        memcpy(posn, hex, 2);
 329        posn += 2;
 330        *(posn++) = '/';
 331        strcpy(posn, hex + 2);
 332        strcpy(request->url, url);
 333
 334        /* If a previous temp file is present, process what was already
 335           fetched. */
 336        prevlocal = open(prevfile, O_RDONLY);
 337        if (prevlocal != -1) {
 338                do {
 339                        prev_read = read(prevlocal, prev_buf, PREV_BUF_SIZE);
 340                        if (prev_read>0) {
 341                                if (fwrite_sha1_file(prev_buf,
 342                                                     1,
 343                                                     prev_read,
 344                                                     request) == prev_read) {
 345                                        prev_posn += prev_read;
 346                                } else {
 347                                        prev_read = -1;
 348                                }
 349                        }
 350                } while (prev_read > 0);
 351                close(prevlocal);
 352        }
 353        unlink(prevfile);
 354
 355        /* Reset inflate/SHA1 if there was an error reading the previous temp
 356           file; also rewind to the beginning of the local file. */
 357        if (prev_read == -1) {
 358                memset(&request->stream, 0, sizeof(request->stream));
 359                inflateInit(&request->stream);
 360                SHA1_Init(&request->c);
 361                if (prev_posn>0) {
 362                        prev_posn = 0;
 363                        lseek(request->local, SEEK_SET, 0);
 364                        ftruncate(request->local, 0);
 365                }
 366        }
 367
 368        slot = get_active_slot();
 369        curl_easy_setopt(slot->curl, CURLOPT_FILE, request);
 370        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);
 371        curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, request->errorstr);
 372        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 373        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 374
 375        /* If we have successfully processed data from a previous fetch
 376           attempt, only fetch the data we don't already have. */
 377        if (prev_posn>0) {
 378                if (get_verbosely)
 379                        fprintf(stderr,
 380                                "Resuming fetch of object %s at byte %ld\n",
 381                                hex, prev_posn);
 382                sprintf(range, "Range: bytes=%ld-", prev_posn);
 383                range_header = curl_slist_append(range_header, range);
 384                curl_easy_setopt(slot->curl,
 385                                 CURLOPT_HTTPHEADER, range_header);
 386        }
 387
 388        /* Try to get the request started, abort the request on error */
 389        if (!start_active_slot(slot)) {
 390                request->state = ABORTED;
 391                close(request->local);
 392                free(request->url);
 393                return;
 394        }
 395        
 396        request->slot = slot;
 397        request->state = ACTIVE;
 398}
 399
 400void finish_request(struct transfer_request *request)
 401{
 402        fchmod(request->local, 0444);
 403        close(request->local);
 404
 405        if (request->http_code == 416) {
 406                fprintf(stderr, "Warning: requested range invalid; we may already have all the data.\n");
 407        } else if (request->curl_result != CURLE_OK) {
 408                return;
 409        }
 410
 411        inflateEnd(&request->stream);
 412        SHA1_Final(request->real_sha1, &request->c);
 413        if (request->zret != Z_STREAM_END) {
 414                unlink(request->tmpfile);
 415                return;
 416        }
 417        if (memcmp(request->sha1, request->real_sha1, 20)) {
 418                unlink(request->tmpfile);
 419                return;
 420        }
 421        request->rename =
 422                move_temp_to_file(request->tmpfile, request->filename);
 423
 424        if (request->rename == 0)
 425                pull_say("got %s\n", sha1_to_hex(request->sha1));
 426}
 427
 428void release_request(struct transfer_request *request)
 429{
 430        struct transfer_request *entry = request_queue_head;
 431
 432        if (request == request_queue_head) {
 433                request_queue_head = request->next;
 434        } else {
 435                while (entry->next != NULL && entry->next != request)
 436                        entry = entry->next;
 437                if (entry->next == request)
 438                        entry->next = entry->next->next;
 439        }
 440
 441        free(request->url);
 442        free(request);
 443}
 444
 445#ifdef USE_CURL_MULTI
 446void process_curl_messages()
 447{
 448        int num_messages;
 449        struct active_request_slot *slot;
 450        struct transfer_request *request = NULL;
 451        CURLMsg *curl_message = curl_multi_info_read(curlm, &num_messages);
 452
 453        while (curl_message != NULL) {
 454                if (curl_message->msg == CURLMSG_DONE) {
 455                        slot = active_queue_head;
 456                        while (slot != NULL &&
 457                               slot->curl != curl_message->easy_handle)
 458                                slot = slot->next;
 459                        if (slot != NULL) {
 460                                curl_multi_remove_handle(curlm, slot->curl);
 461                                active_requests--;
 462                                slot->done = 1;
 463                                slot->in_use = 0;
 464                                slot->curl_result = curl_message->data.result;
 465                                request = request_queue_head;
 466                                while (request != NULL &&
 467                                       request->slot != slot)
 468                                        request = request->next;
 469                        } else {
 470                                fprintf(stderr, "Received DONE message for unknown request!\n");
 471                        }
 472                        if (request != NULL) {
 473                                request->curl_result =
 474                                        curl_message->data.result;
 475                                curl_easy_getinfo(slot->curl,
 476                                                  CURLINFO_HTTP_CODE,
 477                                                  &request->http_code);
 478                                request->slot = NULL;
 479
 480                                /* Use alternates if necessary */
 481                                if (request->http_code == 404 &&
 482                                    request->repo->next != NULL) {
 483                                        request->repo = request->repo->next;
 484                                        start_request(request);
 485                                } else {
 486                                        finish_request(request);
 487                                        request->state = COMPLETE;
 488                                }
 489                        }
 490                } else {
 491                        fprintf(stderr, "Unknown CURL message received: %d\n",
 492                                (int)curl_message->msg);
 493                }
 494                curl_message = curl_multi_info_read(curlm, &num_messages);
 495        }
 496}
 497
 498void process_request_queue()
 499{
 500        struct transfer_request *request = request_queue_head;
 501        int num_transfers;
 502
 503        while (active_requests < max_requests && request != NULL) {
 504                if (request->state == WAITING) {
 505                        if (has_sha1_file(request->sha1))
 506                                release_request(request);
 507                        else
 508                                start_request(request);
 509                        curl_multi_perform(curlm, &num_transfers);
 510                }
 511                request = request->next;
 512        }
 513}
 514#endif
 515
 516void prefetch(unsigned char *sha1)
 517{
 518        struct transfer_request *newreq;
 519        struct transfer_request *tail;
 520        char *filename = sha1_file_name(sha1);
 521
 522        newreq = xmalloc(sizeof(*newreq));
 523        memcpy(newreq->sha1, sha1, 20);
 524        newreq->repo = alt;
 525        newreq->url = NULL;
 526        newreq->local = -1;
 527        newreq->state = WAITING;
 528        snprintf(newreq->filename, sizeof(newreq->filename), "%s", filename);
 529        snprintf(newreq->tmpfile, sizeof(newreq->tmpfile),
 530                 "%s.temp", filename);
 531        newreq->next = NULL;
 532
 533        if (request_queue_head == NULL) {
 534                request_queue_head = newreq;
 535        } else {
 536                tail = request_queue_head;
 537                while (tail->next != NULL) {
 538                        tail = tail->next;
 539                }
 540                tail->next = newreq;
 541        }
 542#ifdef USE_CURL_MULTI
 543        process_request_queue();
 544        process_curl_messages();
 545#endif
 546}
 547
 548static int fetch_index(struct alt_base *repo, unsigned char *sha1)
 549{
 550        char *hex = sha1_to_hex(sha1);
 551        char *filename;
 552        char *url;
 553        char tmpfile[PATH_MAX];
 554        long prev_posn = 0;
 555        char range[RANGE_HEADER_SIZE];
 556        struct curl_slist *range_header = NULL;
 557
 558        FILE *indexfile;
 559        struct active_request_slot *slot;
 560
 561        if (has_pack_index(sha1))
 562                return 0;
 563
 564        if (get_verbosely)
 565                fprintf(stderr, "Getting index for pack %s\n", hex);
 566        
 567        url = xmalloc(strlen(repo->base) + 64);
 568        sprintf(url, "%s/objects/pack/pack-%s.idx", repo->base, hex);
 569        
 570        filename = sha1_pack_index_name(sha1);
 571        snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 572        indexfile = fopen(tmpfile, "a");
 573        if (!indexfile)
 574                return error("Unable to open local file %s for pack index",
 575                             filename);
 576
 577        slot = get_active_slot();
 578        curl_easy_setopt(slot->curl, CURLOPT_FILE, indexfile);
 579        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 580        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 581        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 582        slot->local = indexfile;
 583
 584        /* If there is data present from a previous transfer attempt,
 585           resume where it left off */
 586        prev_posn = ftell(indexfile);
 587        if (prev_posn>0) {
 588                if (get_verbosely)
 589                        fprintf(stderr,
 590                                "Resuming fetch of index for pack %s at byte %ld\n",
 591                                hex, prev_posn);
 592                sprintf(range, "Range: bytes=%ld-", prev_posn);
 593                range_header = curl_slist_append(range_header, range);
 594                curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 595        }
 596
 597        if (start_active_slot(slot)) {
 598                run_active_slot(slot);
 599                if (slot->curl_result != CURLE_OK) {
 600                        fclose(indexfile);
 601                        return error("Unable to get pack index %s\n%s", url,
 602                                     curl_errorstr);
 603                }
 604        } else {
 605                return error("Unable to start request");
 606        }
 607
 608        fclose(indexfile);
 609
 610        return move_temp_to_file(tmpfile, filename);
 611}
 612
 613static int setup_index(struct alt_base *repo, unsigned char *sha1)
 614{
 615        struct packed_git *new_pack;
 616        if (has_pack_file(sha1))
 617                return 0; // don't list this as something we can get
 618
 619        if (fetch_index(repo, sha1))
 620                return -1;
 621
 622        new_pack = parse_pack_index(sha1);
 623        new_pack->next = repo->packs;
 624        repo->packs = new_pack;
 625        return 0;
 626}
 627
 628static int fetch_alternates(char *base)
 629{
 630        int ret = 0;
 631        struct buffer buffer;
 632        char *url;
 633        char *data;
 634        int i = 0;
 635        int http_specific = 1;
 636        struct alt_base *tail = alt;
 637        static const char null_byte = '\0';
 638
 639        struct active_request_slot *slot;
 640
 641        data = xmalloc(4096);
 642        buffer.size = 4096;
 643        buffer.posn = 0;
 644        buffer.buffer = data;
 645
 646        if (get_verbosely)
 647                fprintf(stderr, "Getting alternates list\n");
 648        
 649        url = xmalloc(strlen(base) + 31);
 650        sprintf(url, "%s/objects/info/http-alternates", base);
 651
 652        slot = get_active_slot();
 653        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 654        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
 655                         fwrite_buffer_dynamic);
 656        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 657        if (start_active_slot(slot)) {
 658                run_active_slot(slot);
 659                if (slot->curl_result != CURLE_OK || !buffer.posn) {
 660                        http_specific = 0;
 661
 662                        sprintf(url, "%s/objects/info/alternates", base);
 663
 664                        slot = get_active_slot();
 665                        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 666                        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
 667                                         fwrite_buffer_dynamic);
 668                        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 669                        if (start_active_slot(slot)) {
 670                                run_active_slot(slot);
 671                                if (slot->curl_result != CURLE_OK) {
 672                                        free(buffer.buffer);
 673                                        return 0;
 674                                }
 675                        }
 676                }
 677        } else {
 678                free(buffer.buffer);
 679                return 0;
 680        }
 681
 682        fwrite_buffer_dynamic(&null_byte, 1, 1, &buffer);
 683        buffer.posn--;
 684        data = buffer.buffer;
 685
 686        while (i < buffer.posn) {
 687                int posn = i;
 688                while (posn < buffer.posn && data[posn] != '\n')
 689                        posn++;
 690                if (data[posn] == '\n') {
 691                        int okay = 0;
 692                        int serverlen = 0;
 693                        struct alt_base *newalt;
 694                        char *target = NULL;
 695                        if (data[i] == '/') {
 696                                serverlen = strchr(base + 8, '/') - base;
 697                                okay = 1;
 698                        } else if (!memcmp(data + i, "../", 3)) {
 699                                i += 3;
 700                                serverlen = strlen(base);
 701                                while (i + 2 < posn && 
 702                                       !memcmp(data + i, "../", 3)) {
 703                                        do {
 704                                                serverlen--;
 705                                        } while (serverlen &&
 706                                                 base[serverlen - 1] != '/');
 707                                        i += 3;
 708                                }
 709                                // If the server got removed, give up.
 710                                okay = strchr(base, ':') - base + 3 < 
 711                                        serverlen;
 712                        } else if (http_specific) {
 713                                char *colon = strchr(data + i, ':');
 714                                char *slash = strchr(data + i, '/');
 715                                if (colon && slash && colon < data + posn &&
 716                                    slash < data + posn && colon < slash) {
 717                                        okay = 1;
 718                                }
 719                        }
 720                        // skip 'objects' at end
 721                        if (okay) {
 722                                target = xmalloc(serverlen + posn - i - 6);
 723                                strncpy(target, base, serverlen);
 724                                strncpy(target + serverlen, data + i,
 725                                        posn - i - 7);
 726                                target[serverlen + posn - i - 7] = '\0';
 727                                if (get_verbosely)
 728                                        fprintf(stderr, 
 729                                                "Also look at %s\n", target);
 730                                newalt = xmalloc(sizeof(*newalt));
 731                                newalt->next = NULL;
 732                                newalt->base = target;
 733                                newalt->got_indices = 0;
 734                                newalt->packs = NULL;
 735                                while (tail->next != NULL)
 736                                        tail = tail->next;
 737                                tail->next = newalt;
 738                                ret++;
 739                        }
 740                }
 741                i = posn + 1;
 742        }
 743
 744        free(buffer.buffer);
 745        return ret;
 746}
 747
 748static int fetch_indices(struct alt_base *repo)
 749{
 750        unsigned char sha1[20];
 751        char *url;
 752        struct buffer buffer;
 753        char *data;
 754        int i = 0;
 755
 756        struct active_request_slot *slot;
 757
 758        if (repo->got_indices)
 759                return 0;
 760
 761        data = xmalloc(4096);
 762        buffer.size = 4096;
 763        buffer.posn = 0;
 764        buffer.buffer = data;
 765
 766        if (get_verbosely)
 767                fprintf(stderr, "Getting pack list\n");
 768        
 769        url = xmalloc(strlen(repo->base) + 21);
 770        sprintf(url, "%s/objects/info/packs", repo->base);
 771
 772        slot = get_active_slot();
 773        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
 774        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
 775                         fwrite_buffer_dynamic);
 776        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 777        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
 778        if (start_active_slot(slot)) {
 779                run_active_slot(slot);
 780                if (slot->curl_result != CURLE_OK) {
 781                        free(buffer.buffer);
 782                        return error("%s", curl_errorstr);
 783                }
 784        } else {
 785                free(buffer.buffer);
 786                return error("Unable to start request");
 787        }
 788
 789        data = buffer.buffer;
 790        while (i < buffer.posn) {
 791                switch (data[i]) {
 792                case 'P':
 793                        i++;
 794                        if (i + 52 < buffer.posn &&
 795                            !strncmp(data + i, " pack-", 6) &&
 796                            !strncmp(data + i + 46, ".pack\n", 6)) {
 797                                get_sha1_hex(data + i + 6, sha1);
 798                                setup_index(repo, sha1);
 799                                i += 51;
 800                                break;
 801                        }
 802                default:
 803                        while (data[i] != '\n')
 804                                i++;
 805                }
 806                i++;
 807        }
 808
 809        free(buffer.buffer);
 810        repo->got_indices = 1;
 811        return 0;
 812}
 813
 814static int fetch_pack(struct alt_base *repo, unsigned char *sha1)
 815{
 816        char *url;
 817        struct packed_git *target;
 818        struct packed_git **lst;
 819        FILE *packfile;
 820        char *filename;
 821        char tmpfile[PATH_MAX];
 822        int ret;
 823        long prev_posn = 0;
 824        char range[RANGE_HEADER_SIZE];
 825        struct curl_slist *range_header = NULL;
 826
 827        struct active_request_slot *slot;
 828
 829        if (fetch_indices(repo))
 830                return -1;
 831        target = find_sha1_pack(sha1, repo->packs);
 832        if (!target)
 833                return -1;
 834
 835        if (get_verbosely) {
 836                fprintf(stderr, "Getting pack %s\n",
 837                        sha1_to_hex(target->sha1));
 838                fprintf(stderr, " which contains %s\n",
 839                        sha1_to_hex(sha1));
 840        }
 841
 842        url = xmalloc(strlen(repo->base) + 65);
 843        sprintf(url, "%s/objects/pack/pack-%s.pack",
 844                repo->base, sha1_to_hex(target->sha1));
 845
 846        filename = sha1_pack_name(target->sha1);
 847        snprintf(tmpfile, sizeof(tmpfile), "%s.temp", filename);
 848        packfile = fopen(tmpfile, "a");
 849        if (!packfile)
 850                return error("Unable to open local file %s for pack",
 851                             filename);
 852
 853        slot = get_active_slot();
 854        curl_easy_setopt(slot->curl, CURLOPT_FILE, packfile);
 855        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 856        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 857        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
 858        slot->local = packfile;
 859
 860        /* If there is data present from a previous transfer attempt,
 861           resume where it left off */
 862        prev_posn = ftell(packfile);
 863        if (prev_posn>0) {
 864                if (get_verbosely)
 865                        fprintf(stderr,
 866                                "Resuming fetch of pack %s at byte %ld\n",
 867                                sha1_to_hex(target->sha1), prev_posn);
 868                sprintf(range, "Range: bytes=%ld-", prev_posn);
 869                range_header = curl_slist_append(range_header, range);
 870                curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, range_header);
 871        }
 872
 873        if (start_active_slot(slot)) {
 874                run_active_slot(slot);
 875                if (slot->curl_result != CURLE_OK) {
 876                        fclose(packfile);
 877                        return error("Unable to get pack file %s\n%s", url,
 878                                     curl_errorstr);
 879                }
 880        } else {
 881                return error("Unable to start request");
 882        }
 883
 884        fclose(packfile);
 885
 886        ret = move_temp_to_file(tmpfile, filename);
 887        if (ret)
 888                return ret;
 889
 890        lst = &repo->packs;
 891        while (*lst != target)
 892                lst = &((*lst)->next);
 893        *lst = (*lst)->next;
 894
 895        if (verify_pack(target, 0))
 896                return -1;
 897        install_packed_git(target);
 898
 899        return 0;
 900}
 901
 902static int fetch_object(struct alt_base *repo, unsigned char *sha1)
 903{
 904        char *hex = sha1_to_hex(sha1);
 905        int ret;
 906        struct transfer_request *request = request_queue_head;
 907
 908        while (request != NULL && memcmp(request->sha1, sha1, 20))
 909                request = request->next;
 910        if (request == NULL)
 911                return error("Couldn't find request for %s in the queue", hex);
 912
 913        if (has_sha1_file(request->sha1)) {
 914                release_request(request);
 915                return 0;
 916        }
 917
 918#ifdef USE_CURL_MULTI
 919        int num_transfers;
 920        while (request->state == WAITING) {
 921                curl_multi_perform(curlm, &num_transfers);
 922                if (num_transfers < active_requests) {
 923                        process_curl_messages();
 924                        process_request_queue();
 925                }
 926        }
 927#else
 928        start_request(request);
 929#endif
 930
 931        while (request->state == ACTIVE) {
 932                run_active_slot(request->slot);
 933#ifndef USE_CURL_MULTI
 934                request->curl_result = request->slot->curl_result;
 935                curl_easy_getinfo(request->slot->curl,
 936                                  CURLINFO_HTTP_CODE,
 937                                  &request->http_code);
 938                request->slot = NULL;
 939
 940                /* Use alternates if necessary */
 941                if (request->http_code == 404 &&
 942                    request->repo->next != NULL) {
 943                        request->repo = request->repo->next;
 944                        start_request(request);
 945                } else {
 946                        finish_request(request);
 947                        request->state = COMPLETE;
 948                }
 949#endif
 950        }
 951
 952        if (request->state == ABORTED) {
 953                release_request(request);
 954                return error("Request for %s aborted", hex);
 955        }
 956
 957        if (request->curl_result != CURLE_OK && request->http_code != 416) {
 958                ret = error("%s", request->errorstr);
 959                release_request(request);
 960                return ret;
 961        }
 962
 963        if (request->zret != Z_STREAM_END) {
 964                ret = error("File %s (%s) corrupt\n", hex, request->url);
 965                release_request(request);
 966                return ret;
 967        }
 968
 969        if (memcmp(request->sha1, request->real_sha1, 20)) {
 970                release_request(request);
 971                return error("File %s has bad hash\n", hex);
 972        }
 973
 974        if (request->rename < 0) {
 975                ret = error("unable to write sha1 filename %s: %s",
 976                            request->filename,
 977                            strerror(request->rename));
 978                release_request(request);
 979                return ret;
 980        }
 981
 982        release_request(request);
 983        return 0;
 984}
 985
 986int fetch(unsigned char *sha1)
 987{
 988        struct alt_base *altbase = alt;
 989
 990        if (!fetch_object(altbase, sha1))
 991                return 0;
 992        while (altbase) {
 993                if (!fetch_pack(altbase, sha1))
 994                        return 0;
 995                altbase = altbase->next;
 996        }
 997        return error("Unable to find %s under %s\n", sha1_to_hex(sha1), 
 998                     alt->base);
 999}
1000
1001static inline int needs_quote(int ch)
1002{
1003        switch (ch) {
1004        case '/': case '-': case '.':
1005        case 'A'...'Z': case 'a'...'z': case '0'...'9':
1006                return 0;
1007        default:
1008                return 1;
1009        }
1010}
1011
1012static inline int hex(int v)
1013{
1014        if (v < 10) return '0' + v;
1015        else return 'A' + v - 10;
1016}
1017
1018static char *quote_ref_url(const char *base, const char *ref)
1019{
1020        const char *cp;
1021        char *dp, *qref;
1022        int len, baselen, ch;
1023
1024        baselen = strlen(base);
1025        len = baselen + 6; /* "refs/" + NUL */
1026        for (cp = ref; (ch = *cp) != 0; cp++, len++)
1027                if (needs_quote(ch))
1028                        len += 2; /* extra two hex plus replacement % */
1029        qref = xmalloc(len);
1030        memcpy(qref, base, baselen);
1031        memcpy(qref + baselen, "refs/", 5);
1032        for (cp = ref, dp = qref + baselen + 5; (ch = *cp) != 0; cp++) {
1033                if (needs_quote(ch)) {
1034                        *dp++ = '%';
1035                        *dp++ = hex((ch >> 4) & 0xF);
1036                        *dp++ = hex(ch & 0xF);
1037                }
1038                else
1039                        *dp++ = ch;
1040        }
1041        *dp = 0;
1042
1043        return qref;
1044}
1045
1046int fetch_ref(char *ref, unsigned char *sha1)
1047{
1048        char *url;
1049        char hex[42];
1050        struct buffer buffer;
1051        char *base = alt->base;
1052        struct active_request_slot *slot;
1053        buffer.size = 41;
1054        buffer.posn = 0;
1055        buffer.buffer = hex;
1056        hex[41] = '\0';
1057        
1058        url = quote_ref_url(base, ref);
1059        slot = get_active_slot();
1060        curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
1061        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
1062        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, NULL);
1063        curl_easy_setopt(slot->curl, CURLOPT_URL, url);
1064        if (start_active_slot(slot)) {
1065                run_active_slot(slot);
1066                if (slot->curl_result != CURLE_OK)
1067                        return error("Couldn't get %s for %s\n%s",
1068                                     url, ref, curl_errorstr);
1069        } else {
1070                return error("Unable to start request");
1071        }
1072
1073        hex[40] = '\0';
1074        get_sha1_hex(hex, sha1);
1075        return 0;
1076}
1077
1078int main(int argc, char **argv)
1079{
1080        char *commit_id;
1081        char *url;
1082        int arg = 1;
1083        struct active_request_slot *slot;
1084
1085        while (arg < argc && argv[arg][0] == '-') {
1086                if (argv[arg][1] == 't') {
1087                        get_tree = 1;
1088                } else if (argv[arg][1] == 'c') {
1089                        get_history = 1;
1090                } else if (argv[arg][1] == 'a') {
1091                        get_all = 1;
1092                        get_tree = 1;
1093                        get_history = 1;
1094                } else if (argv[arg][1] == 'v') {
1095                        get_verbosely = 1;
1096                } else if (argv[arg][1] == 'w') {
1097                        write_ref = argv[arg + 1];
1098                        arg++;
1099                } else if (!strcmp(argv[arg], "--recover")) {
1100                        get_recover = 1;
1101                }
1102                arg++;
1103        }
1104        if (argc < arg + 2) {
1105                usage("git-http-fetch [-c] [-t] [-a] [-d] [-v] [--recover] [-w ref] commit-id url");
1106                return 1;
1107        }
1108        commit_id = argv[arg];
1109        url = argv[arg + 1];
1110
1111        curl_global_init(CURL_GLOBAL_ALL);
1112
1113#ifdef USE_CURL_MULTI
1114        char *http_max_requests = getenv("GIT_HTTP_MAX_REQUESTS");
1115        if (http_max_requests != NULL)
1116                max_requests = atoi(http_max_requests);
1117        if (max_requests < 1)
1118                max_requests = DEFAULT_MAX_REQUESTS;
1119
1120        curlm = curl_multi_init();
1121        if (curlm == NULL) {
1122                fprintf(stderr, "Error creating curl multi handle.\n");
1123                return 1;
1124        }
1125#endif
1126        pragma_header = curl_slist_append(pragma_header, "Pragma: no-cache");
1127        no_pragma_header = curl_slist_append(no_pragma_header, "Pragma:");
1128        no_range_header = curl_slist_append(no_range_header, "Range:");
1129
1130        curl_default = curl_easy_init();
1131
1132        curl_ssl_verify = getenv("GIT_SSL_NO_VERIFY") ? 0 : 1;
1133        curl_easy_setopt(curl_default, CURLOPT_SSL_VERIFYPEER, curl_ssl_verify);
1134#if LIBCURL_VERSION_NUM >= 0x070907
1135        curl_easy_setopt(curl_default, CURLOPT_NETRC, CURL_NETRC_OPTIONAL);
1136#endif
1137
1138        if ((ssl_cert = getenv("GIT_SSL_CERT")) != NULL) {
1139                curl_easy_setopt(curl_default, CURLOPT_SSLCERT, ssl_cert);
1140        }
1141#if LIBCURL_VERSION_NUM >= 0x070902
1142        if ((ssl_key = getenv("GIT_SSL_KEY")) != NULL) {
1143                curl_easy_setopt(curl_default, CURLOPT_SSLKEY, ssl_key);
1144        }
1145#endif
1146#if LIBCURL_VERSION_NUM >= 0x070908
1147        if ((ssl_capath = getenv("GIT_SSL_CAPATH")) != NULL) {
1148                curl_easy_setopt(curl_default, CURLOPT_CAPATH, ssl_capath);
1149        }
1150#endif
1151        if ((ssl_cainfo = getenv("GIT_SSL_CAINFO")) != NULL) {
1152                curl_easy_setopt(curl_default, CURLOPT_CAINFO, ssl_cainfo);
1153        }
1154        curl_easy_setopt(curl_default, CURLOPT_FAILONERROR, 1);
1155
1156        alt = xmalloc(sizeof(*alt));
1157        alt->base = url;
1158        alt->got_indices = 0;
1159        alt->packs = NULL;
1160        alt->next = NULL;
1161        fetch_alternates(alt->base);
1162
1163        if (pull(commit_id))
1164                return 1;
1165
1166        curl_slist_free_all(pragma_header);
1167        curl_slist_free_all(no_pragma_header);
1168        curl_slist_free_all(no_range_header);
1169        curl_easy_cleanup(curl_default);
1170        slot = active_queue_head;
1171        while (slot != NULL) {
1172                curl_easy_cleanup(slot->curl);
1173                slot = slot->next;
1174        }
1175#ifdef USE_CURL_MULTI
1176        curl_multi_cleanup(curlm);
1177#endif
1178        curl_global_cleanup();
1179        return 0;
1180}