connect.c

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