Andrew's git / gitweb.git / connect.c
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connect.con commit Add another verbosity level to git-fetch (684f674)
   1#include "git-compat-util.h"
   2#include "cache.h"
   3#include "pkt-line.h"
   4#include "quote.h"
   5#include "refs.h"
   6#include "run-command.h"
   7
   8static char *server_capabilities;
   9
  10static int check_ref(const char *name, int len, unsigned int flags)
  11{
  12        if (!flags)
  13                return 1;
  14
  15        if (len < 5 || memcmp(name, "refs/", 5))
  16                return 0;
  17
  18        /* Skip the "refs/" part */
  19        name += 5;
  20        len -= 5;
  21
  22        /* REF_NORMAL means that we don't want the magic fake tag refs */
  23        if ((flags & REF_NORMAL) && check_ref_format(name) < 0)
  24                return 0;
  25
  26        /* REF_HEADS means that we want regular branch heads */
  27        if ((flags & REF_HEADS) && !memcmp(name, "heads/", 6))
  28                return 1;
  29
  30        /* REF_TAGS means that we want tags */
  31        if ((flags & REF_TAGS) && !memcmp(name, "tags/", 5))
  32                return 1;
  33
  34        /* All type bits clear means that we are ok with anything */
  35        return !(flags & ~REF_NORMAL);
  36}
  37
  38/*
  39 * Read all the refs from the other end
  40 */
  41struct ref **get_remote_heads(int in, struct ref **list,
  42                              int nr_match, char **match,
  43                              unsigned int flags)
  44{
  45        *list = NULL;
  46        for (;;) {
  47                struct ref *ref;
  48                unsigned char old_sha1[20];
  49                static char buffer[1000];
  50                char *name;
  51                int len, name_len;
  52
  53                len = packet_read_line(in, buffer, sizeof(buffer));
  54                if (!len)
  55                        break;
  56                if (buffer[len-1] == '\n')
  57                        buffer[--len] = 0;
  58
  59                if (len < 42 || get_sha1_hex(buffer, old_sha1) || buffer[40] != ' ')
  60                        die("protocol error: expected sha/ref, got '%s'", buffer);
  61                name = buffer + 41;
  62
  63                name_len = strlen(name);
  64                if (len != name_len + 41) {
  65                        if (server_capabilities)
  66                                free(server_capabilities);
  67                        server_capabilities = xstrdup(name + name_len + 1);
  68                }
  69
  70                if (!check_ref(name, name_len, flags))
  71                        continue;
  72                if (nr_match && !path_match(name, nr_match, match))
  73                        continue;
  74                ref = xcalloc(1, sizeof(*ref) + len - 40);
  75                hashcpy(ref->old_sha1, old_sha1);
  76                memcpy(ref->name, buffer + 41, len - 40);
  77                *list = ref;
  78                list = &ref->next;
  79        }
  80        return list;
  81}
  82
  83int server_supports(const char *feature)
  84{
  85        return server_capabilities &&
  86                strstr(server_capabilities, feature) != NULL;
  87}
  88
  89int get_ack(int fd, unsigned char *result_sha1)
  90{
  91        static char line[1000];
  92        int len = packet_read_line(fd, line, sizeof(line));
  93
  94        if (!len)
  95                die("git-fetch-pack: expected ACK/NAK, got EOF");
  96        if (line[len-1] == '\n')
  97                line[--len] = 0;
  98        if (!strcmp(line, "NAK"))
  99                return 0;
 100        if (!prefixcmp(line, "ACK ")) {
 101                if (!get_sha1_hex(line+4, result_sha1)) {
 102                        if (strstr(line+45, "continue"))
 103                                return 2;
 104                        return 1;
 105                }
 106        }
 107        die("git-fetch_pack: expected ACK/NAK, got '%s'", line);
 108}
 109
 110int path_match(const char *path, int nr, char **match)
 111{
 112        int i;
 113        int pathlen = strlen(path);
 114
 115        for (i = 0; i < nr; i++) {
 116                char *s = match[i];
 117                int len = strlen(s);
 118
 119                if (!len || len > pathlen)
 120                        continue;
 121                if (memcmp(path + pathlen - len, s, len))
 122                        continue;
 123                if (pathlen > len && path[pathlen - len - 1] != '/')
 124                        continue;
 125                *s = 0;
 126                return (i + 1);
 127        }
 128        return 0;
 129}
 130
 131struct refspec {
 132        char *src;
 133        char *dst;
 134        char force;
 135};
 136
 137/*
 138 * A:B means fast forward remote B with local A.
 139 * +A:B means overwrite remote B with local A.
 140 * +A is a shorthand for +A:A.
 141 * A is a shorthand for A:A.
 142 * :B means delete remote B.
 143 */
 144static struct refspec *parse_ref_spec(int nr_refspec, char **refspec)
 145{
 146        int i;
 147        struct refspec *rs = xcalloc(sizeof(*rs), (nr_refspec + 1));
 148        for (i = 0; i < nr_refspec; i++) {
 149                char *sp, *dp, *ep;
 150                sp = refspec[i];
 151                if (*sp == '+') {
 152                        rs[i].force = 1;
 153                        sp++;
 154                }
 155                ep = strchr(sp, ':');
 156                if (ep) {
 157                        dp = ep + 1;
 158                        *ep = 0;
 159                }
 160                else
 161                        dp = sp;
 162                rs[i].src = sp;
 163                rs[i].dst = dp;
 164        }
 165        rs[nr_refspec].src = rs[nr_refspec].dst = NULL;
 166        return rs;
 167}
 168
 169static int count_refspec_match(const char *pattern,
 170                               struct ref *refs,
 171                               struct ref **matched_ref)
 172{
 173        int patlen = strlen(pattern);
 174        struct ref *matched_weak = NULL;
 175        struct ref *matched = NULL;
 176        int weak_match = 0;
 177        int match = 0;
 178
 179        for (weak_match = match = 0; refs; refs = refs->next) {
 180                char *name = refs->name;
 181                int namelen = strlen(name);
 182                int weak_match;
 183
 184                if (namelen < patlen ||
 185                    memcmp(name + namelen - patlen, pattern, patlen))
 186                        continue;
 187                if (namelen != patlen && name[namelen - patlen - 1] != '/')
 188                        continue;
 189
 190                /* A match is "weak" if it is with refs outside
 191                 * heads or tags, and did not specify the pattern
 192                 * in full (e.g. "refs/remotes/origin/master") or at
 193                 * least from the toplevel (e.g. "remotes/origin/master");
 194                 * otherwise "git push $URL master" would result in
 195                 * ambiguity between remotes/origin/master and heads/master
 196                 * at the remote site.
 197                 */
 198                if (namelen != patlen &&
 199                    patlen != namelen - 5 &&
 200                    prefixcmp(name, "refs/heads/") &&
 201                    prefixcmp(name, "refs/tags/")) {
 202                        /* We want to catch the case where only weak
 203                         * matches are found and there are multiple
 204                         * matches, and where more than one strong
 205                         * matches are found, as ambiguous.  One
 206                         * strong match with zero or more weak matches
 207                         * are acceptable as a unique match.
 208                         */
 209                        matched_weak = refs;
 210                        weak_match++;
 211                }
 212                else {
 213                        matched = refs;
 214                        match++;
 215                }
 216        }
 217        if (!matched) {
 218                *matched_ref = matched_weak;
 219                return weak_match;
 220        }
 221        else {
 222                *matched_ref = matched;
 223                return match;
 224        }
 225}
 226
 227static void link_dst_tail(struct ref *ref, struct ref ***tail)
 228{
 229        **tail = ref;
 230        *tail = &ref->next;
 231        **tail = NULL;
 232}
 233
 234static struct ref *try_explicit_object_name(const char *name)
 235{
 236        unsigned char sha1[20];
 237        struct ref *ref;
 238        int len;
 239
 240        if (!*name) {
 241                ref = xcalloc(1, sizeof(*ref) + 20);
 242                strcpy(ref->name, "(delete)");
 243                hashclr(ref->new_sha1);
 244                return ref;
 245        }
 246        if (get_sha1(name, sha1))
 247                return NULL;
 248        len = strlen(name) + 1;
 249        ref = xcalloc(1, sizeof(*ref) + len);
 250        memcpy(ref->name, name, len);
 251        hashcpy(ref->new_sha1, sha1);
 252        return ref;
 253}
 254
 255static int match_explicit_refs(struct ref *src, struct ref *dst,
 256                               struct ref ***dst_tail, struct refspec *rs)
 257{
 258        int i, errs;
 259        for (i = errs = 0; rs[i].src; i++) {
 260                struct ref *matched_src, *matched_dst;
 261
 262                matched_src = matched_dst = NULL;
 263                switch (count_refspec_match(rs[i].src, src, &matched_src)) {
 264                case 1:
 265                        break;
 266                case 0:
 267                        /* The source could be in the get_sha1() format
 268                         * not a reference name.  :refs/other is a
 269                         * way to delete 'other' ref at the remote end.
 270                         */
 271                        matched_src = try_explicit_object_name(rs[i].src);
 272                        if (matched_src)
 273                                break;
 274                        errs = 1;
 275                        error("src refspec %s does not match any.",
 276                              rs[i].src);
 277                        break;
 278                default:
 279                        errs = 1;
 280                        error("src refspec %s matches more than one.",
 281                              rs[i].src);
 282                        break;
 283                }
 284                switch (count_refspec_match(rs[i].dst, dst, &matched_dst)) {
 285                case 1:
 286                        break;
 287                case 0:
 288                        if (!memcmp(rs[i].dst, "refs/", 5)) {
 289                                int len = strlen(rs[i].dst) + 1;
 290                                matched_dst = xcalloc(1, sizeof(*dst) + len);
 291                                memcpy(matched_dst->name, rs[i].dst, len);
 292                                link_dst_tail(matched_dst, dst_tail);
 293                        }
 294                        else if (!strcmp(rs[i].src, rs[i].dst) &&
 295                                 matched_src) {
 296                                /* pushing "master:master" when
 297                                 * remote does not have master yet.
 298                                 */
 299                                int len = strlen(matched_src->name) + 1;
 300                                matched_dst = xcalloc(1, sizeof(*dst) + len);
 301                                memcpy(matched_dst->name, matched_src->name,
 302                                       len);
 303                                link_dst_tail(matched_dst, dst_tail);
 304                        }
 305                        else {
 306                                errs = 1;
 307                                error("dst refspec %s does not match any "
 308                                      "existing ref on the remote and does "
 309                                      "not start with refs/.", rs[i].dst);
 310                        }
 311                        break;
 312                default:
 313                        errs = 1;
 314                        error("dst refspec %s matches more than one.",
 315                              rs[i].dst);
 316                        break;
 317                }
 318                if (errs)
 319                        continue;
 320                if (matched_dst->peer_ref) {
 321                        errs = 1;
 322                        error("dst ref %s receives from more than one src.",
 323                              matched_dst->name);
 324                }
 325                else {
 326                        matched_dst->peer_ref = matched_src;
 327                        matched_dst->force = rs[i].force;
 328                }
 329        }
 330        return -errs;
 331}
 332
 333static struct ref *find_ref_by_name(struct ref *list, const char *name)
 334{
 335        for ( ; list; list = list->next)
 336                if (!strcmp(list->name, name))
 337                        return list;
 338        return NULL;
 339}
 340
 341int match_refs(struct ref *src, struct ref *dst, struct ref ***dst_tail,
 342               int nr_refspec, char **refspec, int all)
 343{
 344        struct refspec *rs = parse_ref_spec(nr_refspec, refspec);
 345
 346        if (nr_refspec)
 347                return match_explicit_refs(src, dst, dst_tail, rs);
 348
 349        /* pick the remainder */
 350        for ( ; src; src = src->next) {
 351                struct ref *dst_peer;
 352                if (src->peer_ref)
 353                        continue;
 354                dst_peer = find_ref_by_name(dst, src->name);
 355                if ((dst_peer && dst_peer->peer_ref) || (!dst_peer && !all))
 356                        continue;
 357                if (!dst_peer) {
 358                        /* Create a new one and link it */
 359                        int len = strlen(src->name) + 1;
 360                        dst_peer = xcalloc(1, sizeof(*dst_peer) + len);
 361                        memcpy(dst_peer->name, src->name, len);
 362                        hashcpy(dst_peer->new_sha1, src->new_sha1);
 363                        link_dst_tail(dst_peer, dst_tail);
 364                }
 365                dst_peer->peer_ref = src;
 366        }
 367        return 0;
 368}
 369
 370enum protocol {
 371        PROTO_LOCAL = 1,
 372        PROTO_SSH,
 373        PROTO_GIT,
 374};
 375
 376static enum protocol get_protocol(const char *name)
 377{
 378        if (!strcmp(name, "ssh"))
 379                return PROTO_SSH;
 380        if (!strcmp(name, "git"))
 381                return PROTO_GIT;
 382        if (!strcmp(name, "git+ssh"))
 383                return PROTO_SSH;
 384        if (!strcmp(name, "ssh+git"))
 385                return PROTO_SSH;
 386        die("I don't handle protocol '%s'", name);
 387}
 388
 389#define STR_(s) # s
 390#define STR(s)  STR_(s)
 391
 392#ifndef NO_IPV6
 393
 394static const char *ai_name(const struct addrinfo *ai)
 395{
 396        static char addr[INET_ADDRSTRLEN];
 397        if ( AF_INET == ai->ai_family ) {
 398                struct sockaddr_in *in;
 399                in = (struct sockaddr_in *)ai->ai_addr;
 400                inet_ntop(ai->ai_family, &in->sin_addr, addr, sizeof(addr));
 401        } else if ( AF_INET6 == ai->ai_family ) {
 402                struct sockaddr_in6 *in;
 403                in = (struct sockaddr_in6 *)ai->ai_addr;
 404                inet_ntop(ai->ai_family, &in->sin6_addr, addr, sizeof(addr));
 405        } else {
 406                strcpy(addr, "(unknown)");
 407        }
 408        return addr;
 409}
 410
 411/*
 412 * Returns a connected socket() fd, or else die()s.
 413 */
 414static int git_tcp_connect_sock(char *host, int flags)
 415{
 416        int sockfd = -1, saved_errno = 0;
 417        char *colon, *end;
 418        const char *port = STR(DEFAULT_GIT_PORT);
 419        struct addrinfo hints, *ai0, *ai;
 420        int gai;
 421        int cnt = 0;
 422
 423        if (host[0] == '[') {
 424                end = strchr(host + 1, ']');
 425                if (end) {
 426                        *end = 0;
 427                        end++;
 428                        host++;
 429                } else
 430                        end = host;
 431        } else
 432                end = host;
 433        colon = strchr(end, ':');
 434
 435        if (colon) {
 436                *colon = 0;
 437                port = colon + 1;
 438                if (!*port)
 439                        port = "<none>";
 440        }
 441
 442        memset(&hints, 0, sizeof(hints));
 443        hints.ai_socktype = SOCK_STREAM;
 444        hints.ai_protocol = IPPROTO_TCP;
 445
 446        if (flags & CONNECT_VERBOSE)
 447                fprintf(stderr, "Looking up %s ... ", host);
 448
 449        gai = getaddrinfo(host, port, &hints, &ai);
 450        if (gai)
 451                die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
 452
 453        if (flags & CONNECT_VERBOSE)
 454                fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 455
 456        for (ai0 = ai; ai; ai = ai->ai_next) {
 457                sockfd = socket(ai->ai_family,
 458                                ai->ai_socktype, ai->ai_protocol);
 459                if (sockfd < 0) {
 460                        saved_errno = errno;
 461                        continue;
 462                }
 463                if (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 464                        saved_errno = errno;
 465                        fprintf(stderr, "%s[%d: %s]: net=%s, errno=%s\n",
 466                                host,
 467                                cnt,
 468                                ai_name(ai),
 469                                hstrerror(h_errno),
 470                                strerror(saved_errno));
 471                        close(sockfd);
 472                        sockfd = -1;
 473                        continue;
 474                }
 475                if (flags & CONNECT_VERBOSE)
 476                        fprintf(stderr, "%s ", ai_name(ai));
 477                break;
 478        }
 479
 480        freeaddrinfo(ai0);
 481
 482        if (sockfd < 0)
 483                die("unable to connect a socket (%s)", strerror(saved_errno));
 484
 485        if (flags & CONNECT_VERBOSE)
 486                fprintf(stderr, "done.\n");
 487
 488        return sockfd;
 489}
 490
 491#else /* NO_IPV6 */
 492
 493/*
 494 * Returns a connected socket() fd, or else die()s.
 495 */
 496static int git_tcp_connect_sock(char *host, int flags)
 497{
 498        int sockfd = -1, saved_errno = 0;
 499        char *colon, *end;
 500        char *port = STR(DEFAULT_GIT_PORT), *ep;
 501        struct hostent *he;
 502        struct sockaddr_in sa;
 503        char **ap;
 504        unsigned int nport;
 505        int cnt;
 506
 507        if (host[0] == '[') {
 508                end = strchr(host + 1, ']');
 509                if (end) {
 510                        *end = 0;
 511                        end++;
 512                        host++;
 513                } else
 514                        end = host;
 515        } else
 516                end = host;
 517        colon = strchr(end, ':');
 518
 519        if (colon) {
 520                *colon = 0;
 521                port = colon + 1;
 522        }
 523
 524        if (flags & CONNECT_VERBOSE)
 525                fprintf(stderr, "Looking up %s ... ", host);
 526
 527        he = gethostbyname(host);
 528        if (!he)
 529                die("Unable to look up %s (%s)", host, hstrerror(h_errno));
 530        nport = strtoul(port, &ep, 10);
 531        if ( ep == port || *ep ) {
 532                /* Not numeric */
 533                struct servent *se = getservbyname(port,"tcp");
 534                if ( !se )
 535                        die("Unknown port %s\n", port);
 536                nport = se->s_port;
 537        }
 538
 539        if (flags & CONNECT_VERBOSE)
 540                fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 541
 542        for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
 543                sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 544                if (sockfd < 0) {
 545                        saved_errno = errno;
 546                        continue;
 547                }
 548
 549                memset(&sa, 0, sizeof sa);
 550                sa.sin_family = he->h_addrtype;
 551                sa.sin_port = htons(nport);
 552                memcpy(&sa.sin_addr, *ap, he->h_length);
 553
 554                if (connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 555                        saved_errno = errno;
 556                        fprintf(stderr, "%s[%d: %s]: net=%s, errno=%s\n",
 557                                host,
 558                                cnt,
 559                                inet_ntoa(*(struct in_addr *)&sa.sin_addr),
 560                                hstrerror(h_errno),
 561                                strerror(saved_errno));
 562                        close(sockfd);
 563                        sockfd = -1;
 564                        continue;
 565                }
 566                if (flags & CONNECT_VERBOSE)
 567                        fprintf(stderr, "%s ",
 568                                inet_ntoa(*(struct in_addr *)&sa.sin_addr));
 569                break;
 570        }
 571
 572        if (sockfd < 0)
 573                die("unable to connect a socket (%s)", strerror(saved_errno));
 574
 575        if (flags & CONNECT_VERBOSE)
 576                fprintf(stderr, "done.\n");
 577
 578        return sockfd;
 579}
 580
 581#endif /* NO_IPV6 */
 582
 583
 584static void git_tcp_connect(int fd[2], char *host, int flags)
 585{
 586        int sockfd = git_tcp_connect_sock(host, flags);
 587
 588        fd[0] = sockfd;
 589        fd[1] = dup(sockfd);
 590}
 591
 592
 593static char *git_proxy_command;
 594static const char *rhost_name;
 595static int rhost_len;
 596
 597static int git_proxy_command_options(const char *var, const char *value)
 598{
 599        if (!strcmp(var, "core.gitproxy")) {
 600                const char *for_pos;
 601                int matchlen = -1;
 602                int hostlen;
 603
 604                if (git_proxy_command)
 605                        return 0;
 606                /* [core]
 607                 * ;# matches www.kernel.org as well
 608                 * gitproxy = netcatter-1 for kernel.org
 609                 * gitproxy = netcatter-2 for sample.xz
 610                 * gitproxy = netcatter-default
 611                 */
 612                for_pos = strstr(value, " for ");
 613                if (!for_pos)
 614                        /* matches everybody */
 615                        matchlen = strlen(value);
 616                else {
 617                        hostlen = strlen(for_pos + 5);
 618                        if (rhost_len < hostlen)
 619                                matchlen = -1;
 620                        else if (!strncmp(for_pos + 5,
 621                                          rhost_name + rhost_len - hostlen,
 622                                          hostlen) &&
 623                                 ((rhost_len == hostlen) ||
 624                                  rhost_name[rhost_len - hostlen -1] == '.'))
 625                                matchlen = for_pos - value;
 626                        else
 627                                matchlen = -1;
 628                }
 629                if (0 <= matchlen) {
 630                        /* core.gitproxy = none for kernel.org */
 631                        if (matchlen == 4 && 
 632                            !memcmp(value, "none", 4))
 633                                matchlen = 0;
 634                        git_proxy_command = xmalloc(matchlen + 1);
 635                        memcpy(git_proxy_command, value, matchlen);
 636                        git_proxy_command[matchlen] = 0;
 637                }
 638                return 0;
 639        }
 640
 641        return git_default_config(var, value);
 642}
 643
 644static int git_use_proxy(const char *host)
 645{
 646        rhost_name = host;
 647        rhost_len = strlen(host);
 648        git_proxy_command = getenv("GIT_PROXY_COMMAND");
 649        git_config(git_proxy_command_options);
 650        rhost_name = NULL;
 651        return (git_proxy_command && *git_proxy_command);
 652}
 653
 654static void git_proxy_connect(int fd[2], char *host)
 655{
 656        const char *port = STR(DEFAULT_GIT_PORT);
 657        char *colon, *end;
 658        const char *argv[4];
 659        struct child_process proxy;
 660
 661        if (host[0] == '[') {
 662                end = strchr(host + 1, ']');
 663                if (end) {
 664                        *end = 0;
 665                        end++;
 666                        host++;
 667                } else
 668                        end = host;
 669        } else
 670                end = host;
 671        colon = strchr(end, ':');
 672
 673        if (colon) {
 674                *colon = 0;
 675                port = colon + 1;
 676        }
 677
 678        argv[0] = git_proxy_command;
 679        argv[1] = host;
 680        argv[2] = port;
 681        argv[3] = NULL;
 682        memset(&proxy, 0, sizeof(proxy));
 683        proxy.argv = argv;
 684        proxy.in = -1;
 685        proxy.out = -1;
 686        if (start_command(&proxy))
 687                die("cannot start proxy %s", argv[0]);
 688        fd[0] = proxy.out; /* read from proxy stdout */
 689        fd[1] = proxy.in;  /* write to proxy stdin */
 690}
 691
 692#define MAX_CMD_LEN 1024
 693
 694/*
 695 * This returns 0 if the transport protocol does not need fork(2),
 696 * or a process id if it does.  Once done, finish the connection
 697 * with finish_connect() with the value returned from this function
 698 * (it is safe to call finish_connect() with 0 to support the former
 699 * case).
 700 *
 701 * Does not return a negative value on error; it just dies.
 702 */
 703pid_t git_connect(int fd[2], char *url, const char *prog, int flags)
 704{
 705        char *host, *path = url;
 706        char *end;
 707        int c;
 708        int pipefd[2][2];
 709        pid_t pid;
 710        enum protocol protocol = PROTO_LOCAL;
 711        int free_path = 0;
 712
 713        /* Without this we cannot rely on waitpid() to tell
 714         * what happened to our children.
 715         */
 716        signal(SIGCHLD, SIG_DFL);
 717
 718        host = strstr(url, "://");
 719        if(host) {
 720                *host = '\0';
 721                protocol = get_protocol(url);
 722                host += 3;
 723                c = '/';
 724        } else {
 725                host = url;
 726                c = ':';
 727        }
 728
 729        if (host[0] == '[') {
 730                end = strchr(host + 1, ']');
 731                if (end) {
 732                        *end = 0;
 733                        end++;
 734                        host++;
 735                } else
 736                        end = host;
 737        } else
 738                end = host;
 739
 740        path = strchr(end, c);
 741        if (c == ':') {
 742                if (path) {
 743                        protocol = PROTO_SSH;
 744                        *path++ = '\0';
 745                } else
 746                        path = host;
 747        }
 748
 749        if (!path || !*path)
 750                die("No path specified. See 'man git-pull' for valid url syntax");
 751
 752        /*
 753         * null-terminate hostname and point path to ~ for URL's like this:
 754         *    ssh://host.xz/~user/repo
 755         */
 756        if (protocol != PROTO_LOCAL && host != url) {
 757                char *ptr = path;
 758                if (path[1] == '~')
 759                        path++;
 760                else {
 761                        path = xstrdup(ptr);
 762                        free_path = 1;
 763                }
 764
 765                *ptr = '\0';
 766        }
 767
 768        if (protocol == PROTO_GIT) {
 769                /* These underlying connection commands die() if they
 770                 * cannot connect.
 771                 */
 772                char *target_host = xstrdup(host);
 773                if (git_use_proxy(host))
 774                        git_proxy_connect(fd, host);
 775                else
 776                        git_tcp_connect(fd, host, flags);
 777                /*
 778                 * Separate original protocol components prog and path
 779                 * from extended components with a NUL byte.
 780                 */
 781                packet_write(fd[1],
 782                             "%s %s%chost=%s%c",
 783                             prog, path, 0,
 784                             target_host, 0);
 785                free(target_host);
 786                if (free_path)
 787                        free(path);
 788                return 0;
 789        }
 790
 791        if (pipe(pipefd[0]) < 0 || pipe(pipefd[1]) < 0)
 792                die("unable to create pipe pair for communication");
 793        pid = fork();
 794        if (pid < 0)
 795                die("unable to fork");
 796        if (!pid) {
 797                char command[MAX_CMD_LEN];
 798                char *posn = command;
 799                int size = MAX_CMD_LEN;
 800                int of = 0;
 801
 802                of |= add_to_string(&posn, &size, prog, 0);
 803                of |= add_to_string(&posn, &size, " ", 0);
 804                of |= add_to_string(&posn, &size, path, 1);
 805
 806                if (of)
 807                        die("command line too long");
 808
 809                dup2(pipefd[1][0], 0);
 810                dup2(pipefd[0][1], 1);
 811                close(pipefd[0][0]);
 812                close(pipefd[0][1]);
 813                close(pipefd[1][0]);
 814                close(pipefd[1][1]);
 815                if (protocol == PROTO_SSH) {
 816                        const char *ssh, *ssh_basename;
 817                        ssh = getenv("GIT_SSH");
 818                        if (!ssh) ssh = "ssh";
 819                        ssh_basename = strrchr(ssh, '/');
 820                        if (!ssh_basename)
 821                                ssh_basename = ssh;
 822                        else
 823                                ssh_basename++;
 824                        execlp(ssh, ssh_basename, host, command, NULL);
 825                }
 826                else {
 827                        unsetenv(ALTERNATE_DB_ENVIRONMENT);
 828                        unsetenv(DB_ENVIRONMENT);
 829                        unsetenv(GIT_DIR_ENVIRONMENT);
 830                        unsetenv(GRAFT_ENVIRONMENT);
 831                        unsetenv(INDEX_ENVIRONMENT);
 832                        execlp("sh", "sh", "-c", command, NULL);
 833                }
 834                die("exec failed");
 835        }
 836        fd[0] = pipefd[0][0];
 837        fd[1] = pipefd[1][1];
 838        close(pipefd[0][1]);
 839        close(pipefd[1][0]);
 840        if (free_path)
 841                free(path);
 842        return pid;
 843}
 844
 845int finish_connect(pid_t pid)
 846{
 847        if (pid == 0)
 848                return 0;
 849
 850        while (waitpid(pid, NULL, 0) < 0) {
 851                if (errno != EINTR)
 852                        return -1;
 853        }
 854        return 0;
 855}