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