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 "run-command.h"
   7 #include "remote.h"
   8 #include "connect.h"
   9 #include "url.h"
  10 #include "string-list.h"
  11 #include "sha1-array.h"
  12
  13 static char *server_capabilities;
  14 static const char *parse_feature_value(const char *, const char *, int *);
  15
  16 static int check_ref(const char *name, unsigned int flags)
  17 {
  18         if (!flags)
  19                 return 1;
  20
  21         if (!skip_prefix(name, "refs/", &name))
  22                 return 0;
  23
  24         /* REF_NORMAL means that we don't want the magic fake tag refs */
  25         if ((flags & REF_NORMAL) && check_refname_format(name, 0))
  26                 return 0;
  27
  28         /* REF_HEADS means that we want regular branch heads */
  29         if ((flags & REF_HEADS) && starts_with(name, "heads/"))
  30                 return 1;
  31
  32         /* REF_TAGS means that we want tags */
  33         if ((flags & REF_TAGS) && starts_with(name, "tags/"))
  34                 return 1;
  35
  36         /* All type bits clear means that we are ok with anything */
  37         return !(flags & ~REF_NORMAL);
  38 }
  39
  40 int check_ref_type(const struct ref *ref, int flags)
  41 {
  42         return check_ref(ref->name, flags);
  43 }
  44
  45 static void die_initial_contact(int got_at_least_one_head)
  46 {
  47         if (got_at_least_one_head)
  48                 die("The remote end hung up upon initial contact");
  49         else
  50                 die("Could not read from remote repository.\n\n"
  51                     "Please make sure you have the correct access rights\n"
  52                     "and the repository exists.");
  53 }
  54
  55 static void parse_one_symref_info(struct string_list *symref, const char *val, int len)
  56 {
  57         char *sym, *target;
  58         struct string_list_item *item;
  59
  60         if (!len)
  61                 return; /* just "symref" */
  62         /* e.g. "symref=HEAD:refs/heads/master" */
  63         sym = xmemdupz(val, len);
  64         target = strchr(sym, ':');
  65         if (!target)
  66                 /* just "symref=something" */
  67                 goto reject;
  68         *(target++) = '\0';
  69         if (check_refname_format(sym, REFNAME_ALLOW_ONELEVEL) ||
  70             check_refname_format(target, REFNAME_ALLOW_ONELEVEL))
  71                 /* "symref=bogus:pair */
  72                 goto reject;
  73         item = string_list_append(symref, sym);
  74         item->util = target;
  75         return;
  76 reject:
  77         free(sym);
  78         return;
  79 }
  80
  81 static void annotate_refs_with_symref_info(struct ref *ref)
  82 {
  83         struct string_list symref = STRING_LIST_INIT_DUP;
  84         const char *feature_list = server_capabilities;
  85
  86         while (feature_list) {
  87                 int len;
  88                 const char *val;
  89
  90                 val = parse_feature_value(feature_list, "symref", &len);
  91                 if (!val)
  92                         break;
  93                 parse_one_symref_info(&symref, val, len);
  94                 feature_list = val + 1;
  95         }
  96         string_list_sort(&symref);
  97
  98         for (; ref; ref = ref->next) {
  99                 struct string_list_item *item;
 100                 item = string_list_lookup(&symref, ref->name);
 101                 if (!item)
 102                         continue;
 103                 ref->symref = xstrdup((char *)item->util);
 104         }
 105         string_list_clear(&symref, 0);
 106 }
 107
 108 /*
 109  * Read all the refs from the other end
 110  */
 111 struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
 112                               struct ref **list, unsigned int flags,
 113                               struct sha1_array *extra_have,
 114                               struct sha1_array *shallow_points)
 115 {
 116         struct ref **orig_list = list;
 117         int got_at_least_one_head = 0;
 118
 119         *list = NULL;
 120         for (;;) {
 121                 struct ref *ref;
 122                 unsigned char old_sha1[20];
 123                 char *name;
 124                 int len, name_len;
 125                 char *buffer = packet_buffer;
 126                 const char *arg;
 127
 128                 len = packet_read(in, &src_buf, &src_len,
 129                                   packet_buffer, sizeof(packet_buffer),
 130                                   PACKET_READ_GENTLE_ON_EOF |
 131                                   PACKET_READ_CHOMP_NEWLINE);
 132                 if (len < 0)
 133                         die_initial_contact(got_at_least_one_head);
 134
 135                 if (!len)
 136                         break;
 137
 138                 if (len > 4 && skip_prefix(buffer, "ERR ", &arg))
 139                         die("remote error: %s", arg);
 140
 141                 if (len == 48 && skip_prefix(buffer, "shallow ", &arg)) {
 142                         if (get_sha1_hex(arg, old_sha1))
 143                                 die("protocol error: expected shallow sha-1, got '%s'", arg);
 144                         if (!shallow_points)
 145                                 die("repository on the other end cannot be shallow");
 146                         sha1_array_append(shallow_points, old_sha1);
 147                         continue;
 148                 }
 149
 150                 if (len < 42 || get_sha1_hex(buffer, old_sha1) || buffer[40] != ' ')
 151                         die("protocol error: expected sha/ref, got '%s'", buffer);
 152                 name = buffer + 41;
 153
 154                 name_len = strlen(name);
 155                 if (len != name_len + 41) {
 156                         free(server_capabilities);
 157                         server_capabilities = xstrdup(name + name_len + 1);
 158                 }
 159
 160                 if (extra_have && !strcmp(name, ".have")) {
 161                         sha1_array_append(extra_have, old_sha1);
 162                         continue;
 163                 }
 164
 165                 if (!check_ref(name, flags))
 166                         continue;
 167                 ref = alloc_ref(buffer + 41);
 168                 hashcpy(ref->old_sha1, old_sha1);
 169                 *list = ref;
 170                 list = &ref->next;
 171                 got_at_least_one_head = 1;
 172         }
 173
 174         annotate_refs_with_symref_info(*orig_list);
 175
 176         return list;
 177 }
 178
 179 static const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
 180 {
 181         int len;
 182
 183         if (!feature_list)
 184                 return NULL;
 185
 186         len = strlen(feature);
 187         while (*feature_list) {
 188                 const char *found = strstr(feature_list, feature);
 189                 if (!found)
 190                         return NULL;
 191                 if (feature_list == found || isspace(found[-1])) {
 192                         const char *value = found + len;
 193                         /* feature with no value (e.g., "thin-pack") */
 194                         if (!*value || isspace(*value)) {
 195                                 if (lenp)
 196                                         *lenp = 0;
 197                                 return value;
 198                         }
 199                         /* feature with a value (e.g., "agent=git/1.2.3") */
 200                         else if (*value == '=') {
 201                                 value++;
 202                                 if (lenp)
 203                                         *lenp = strcspn(value, " \t\n");
 204                                 return value;
 205                         }
 206                         /*
 207                          * otherwise we matched a substring of another feature;
 208                          * keep looking
 209                          */
 210                 }
 211                 feature_list = found + 1;
 212         }
 213         return NULL;
 214 }
 215
 216 int parse_feature_request(const char *feature_list, const char *feature)
 217 {
 218         return !!parse_feature_value(feature_list, feature, NULL);
 219 }
 220
 221 const char *server_feature_value(const char *feature, int *len)
 222 {
 223         return parse_feature_value(server_capabilities, feature, len);
 224 }
 225
 226 int server_supports(const char *feature)
 227 {
 228         return !!server_feature_value(feature, NULL);
 229 }
 230
 231 enum protocol {
 232         PROTO_LOCAL = 1,
 233         PROTO_FILE,
 234         PROTO_SSH,
 235         PROTO_GIT
 236 };
 237
 238 int url_is_local_not_ssh(const char *url)
 239 {
 240         const char *colon = strchr(url, ':');
 241         const char *slash = strchr(url, '/');
 242         return !colon || (slash && slash < colon) ||
 243                 has_dos_drive_prefix(url);
 244 }
 245
 246 static const char *prot_name(enum protocol protocol)
 247 {
 248         switch (protocol) {
 249                 case PROTO_LOCAL:
 250                 case PROTO_FILE:
 251                         return "file";
 252                 case PROTO_SSH:
 253                         return "ssh";
 254                 case PROTO_GIT:
 255                         return "git";
 256                 default:
 257                         return "unkown protocol";
 258         }
 259 }
 260
 261 static enum protocol get_protocol(const char *name)
 262 {
 263         if (!strcmp(name, "ssh"))
 264                 return PROTO_SSH;
 265         if (!strcmp(name, "git"))
 266                 return PROTO_GIT;
 267         if (!strcmp(name, "git+ssh"))
 268                 return PROTO_SSH;
 269         if (!strcmp(name, "ssh+git"))
 270                 return PROTO_SSH;
 271         if (!strcmp(name, "file"))
 272                 return PROTO_FILE;
 273         die("I don't handle protocol '%s'", name);
 274 }
 275
 276 #define STR_(s) # s
 277 #define STR(s)  STR_(s)
 278
 279 static void get_host_and_port(char **host, const char **port)
 280 {
 281         char *colon, *end;
 282
 283         if (*host[0] == '[') {
 284                 end = strchr(*host + 1, ']');
 285                 if (end) {
 286                         *end = 0;
 287                         end++;
 288                         (*host)++;
 289                 } else
 290                         end = *host;
 291         } else
 292                 end = *host;
 293         colon = strchr(end, ':');
 294
 295         if (colon) {
 296                 *colon = 0;
 297                 *port = colon + 1;
 298         }
 299 }
 300
 301 static void enable_keepalive(int sockfd)
 302 {
 303         int ka = 1;
 304
 305         if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
 306                 fprintf(stderr, "unable to set SO_KEEPALIVE on socket: %s\n",
 307                         strerror(errno));
 308 }
 309
 310 #ifndef NO_IPV6
 311
 312 static const char *ai_name(const struct addrinfo *ai)
 313 {
 314         static char addr[NI_MAXHOST];
 315         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
 316                         NI_NUMERICHOST) != 0)
 317                 strcpy(addr, "(unknown)");
 318
 319         return addr;
 320 }
 321
 322 /*
 323  * Returns a connected socket() fd, or else die()s.
 324  */
 325 static int git_tcp_connect_sock(char *host, int flags)
 326 {
 327         struct strbuf error_message = STRBUF_INIT;
 328         int sockfd = -1;
 329         const char *port = STR(DEFAULT_GIT_PORT);
 330         struct addrinfo hints, *ai0, *ai;
 331         int gai;
 332         int cnt = 0;
 333
 334         get_host_and_port(&host, &port);
 335         if (!*port)
 336                 port = "<none>";
 337
 338         memset(&hints, 0, sizeof(hints));
 339         hints.ai_socktype = SOCK_STREAM;
 340         hints.ai_protocol = IPPROTO_TCP;
 341
 342         if (flags & CONNECT_VERBOSE)
 343                 fprintf(stderr, "Looking up %s ... ", host);
 344
 345         gai = getaddrinfo(host, port, &hints, &ai);
 346         if (gai)
 347                 die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
 348
 349         if (flags & CONNECT_VERBOSE)
 350                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 351
 352         for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
 353                 sockfd = socket(ai->ai_family,
 354                                 ai->ai_socktype, ai->ai_protocol);
 355                 if ((sockfd < 0) ||
 356                     (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
 357                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 358                                     host, cnt, ai_name(ai), strerror(errno));
 359                         if (0 <= sockfd)
 360                                 close(sockfd);
 361                         sockfd = -1;
 362                         continue;
 363                 }
 364                 if (flags & CONNECT_VERBOSE)
 365                         fprintf(stderr, "%s ", ai_name(ai));
 366                 break;
 367         }
 368
 369         freeaddrinfo(ai0);
 370
 371         if (sockfd < 0)
 372                 die("unable to connect to %s:\n%s", host, error_message.buf);
 373
 374         enable_keepalive(sockfd);
 375
 376         if (flags & CONNECT_VERBOSE)
 377                 fprintf(stderr, "done.\n");
 378
 379         strbuf_release(&error_message);
 380
 381         return sockfd;
 382 }
 383
 384 #else /* NO_IPV6 */
 385
 386 /*
 387  * Returns a connected socket() fd, or else die()s.
 388  */
 389 static int git_tcp_connect_sock(char *host, int flags)
 390 {
 391         struct strbuf error_message = STRBUF_INIT;
 392         int sockfd = -1;
 393         const char *port = STR(DEFAULT_GIT_PORT);
 394         char *ep;
 395         struct hostent *he;
 396         struct sockaddr_in sa;
 397         char **ap;
 398         unsigned int nport;
 399         int cnt;
 400
 401         get_host_and_port(&host, &port);
 402
 403         if (flags & CONNECT_VERBOSE)
 404                 fprintf(stderr, "Looking up %s ... ", host);
 405
 406         he = gethostbyname(host);
 407         if (!he)
 408                 die("Unable to look up %s (%s)", host, hstrerror(h_errno));
 409         nport = strtoul(port, &ep, 10);
 410         if ( ep == port || *ep ) {
 411                 /* Not numeric */
 412                 struct servent *se = getservbyname(port,"tcp");
 413                 if ( !se )
 414                         die("Unknown port %s", port);
 415                 nport = se->s_port;
 416         }
 417
 418         if (flags & CONNECT_VERBOSE)
 419                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 420
 421         for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
 422                 memset(&sa, 0, sizeof sa);
 423                 sa.sin_family = he->h_addrtype;
 424                 sa.sin_port = htons(nport);
 425                 memcpy(&sa.sin_addr, *ap, he->h_length);
 426
 427                 sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 428                 if ((sockfd < 0) ||
 429                     connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 430                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 431                                 host,
 432                                 cnt,
 433                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr),
 434                                 strerror(errno));
 435                         if (0 <= sockfd)
 436                                 close(sockfd);
 437                         sockfd = -1;
 438                         continue;
 439                 }
 440                 if (flags & CONNECT_VERBOSE)
 441                         fprintf(stderr, "%s ",
 442                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr));
 443                 break;
 444         }
 445
 446         if (sockfd < 0)
 447                 die("unable to connect to %s:\n%s", host, error_message.buf);
 448
 449         enable_keepalive(sockfd);
 450
 451         if (flags & CONNECT_VERBOSE)
 452                 fprintf(stderr, "done.\n");
 453
 454         return sockfd;
 455 }
 456
 457 #endif /* NO_IPV6 */
 458
 459
 460 static void git_tcp_connect(int fd[2], char *host, int flags)
 461 {
 462         int sockfd = git_tcp_connect_sock(host, flags);
 463
 464         fd[0] = sockfd;
 465         fd[1] = dup(sockfd);
 466 }
 467
 468
 469 static char *git_proxy_command;
 470
 471 static int git_proxy_command_options(const char *var, const char *value,
 472                 void *cb)
 473 {
 474         if (!strcmp(var, "core.gitproxy")) {
 475                 const char *for_pos;
 476                 int matchlen = -1;
 477                 int hostlen;
 478                 const char *rhost_name = cb;
 479                 int rhost_len = strlen(rhost_name);
 480
 481                 if (git_proxy_command)
 482                         return 0;
 483                 if (!value)
 484                         return config_error_nonbool(var);
 485                 /* [core]
 486                  * ;# matches www.kernel.org as well
 487                  * gitproxy = netcatter-1 for kernel.org
 488                  * gitproxy = netcatter-2 for sample.xz
 489                  * gitproxy = netcatter-default
 490                  */
 491                 for_pos = strstr(value, " for ");
 492                 if (!for_pos)
 493                         /* matches everybody */
 494                         matchlen = strlen(value);
 495                 else {
 496                         hostlen = strlen(for_pos + 5);
 497                         if (rhost_len < hostlen)
 498                                 matchlen = -1;
 499                         else if (!strncmp(for_pos + 5,
 500                                           rhost_name + rhost_len - hostlen,
 501                                           hostlen) &&
 502                                  ((rhost_len == hostlen) ||
 503                                   rhost_name[rhost_len - hostlen -1] == '.'))
 504                                 matchlen = for_pos - value;
 505                         else
 506                                 matchlen = -1;
 507                 }
 508                 if (0 <= matchlen) {
 509                         /* core.gitproxy = none for kernel.org */
 510                         if (matchlen == 4 &&
 511                             !memcmp(value, "none", 4))
 512                                 matchlen = 0;
 513                         git_proxy_command = xmemdupz(value, matchlen);
 514                 }
 515                 return 0;
 516         }
 517
 518         return git_default_config(var, value, cb);
 519 }
 520
 521 static int git_use_proxy(const char *host)
 522 {
 523         git_proxy_command = getenv("GIT_PROXY_COMMAND");
 524         git_config(git_proxy_command_options, (void*)host);
 525         return (git_proxy_command && *git_proxy_command);
 526 }
 527
 528 static struct child_process *git_proxy_connect(int fd[2], char *host)
 529 {
 530         const char *port = STR(DEFAULT_GIT_PORT);
 531         struct child_process *proxy;
 532
 533         get_host_and_port(&host, &port);
 534
 535         proxy = xmalloc(sizeof(*proxy));
 536         child_process_init(proxy);
 537         argv_array_push(&proxy->args, git_proxy_command);
 538         argv_array_push(&proxy->args, host);
 539         argv_array_push(&proxy->args, port);
 540         proxy->in = -1;
 541         proxy->out = -1;
 542         if (start_command(proxy))
 543                 die("cannot start proxy %s", git_proxy_command);
 544         fd[0] = proxy->out; /* read from proxy stdout */
 545         fd[1] = proxy->in;  /* write to proxy stdin */
 546         return proxy;
 547 }
 548
 549 static const char *get_port_numeric(const char *p)
 550 {
 551         char *end;
 552         if (p) {
 553                 long port = strtol(p + 1, &end, 10);
 554                 if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
 555                         return p;
 556                 }
 557         }
 558
 559         return NULL;
 560 }
 561
 562 /*
 563  * Extract protocol and relevant parts from the specified connection URL.
 564  * The caller must free() the returned strings.
 565  */
 566 static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
 567                                        char **ret_path)
 568 {
 569         char *url;
 570         char *host, *path;
 571         char *end;
 572         int separator = '/';
 573         enum protocol protocol = PROTO_LOCAL;
 574
 575         if (is_url(url_orig))
 576                 url = url_decode(url_orig);
 577         else
 578                 url = xstrdup(url_orig);
 579
 580         host = strstr(url, "://");
 581         if (host) {
 582                 *host = '\0';
 583                 protocol = get_protocol(url);
 584                 host += 3;
 585         } else {
 586                 host = url;
 587                 if (!url_is_local_not_ssh(url)) {
 588                         protocol = PROTO_SSH;
 589                         separator = ':';
 590                 }
 591         }
 592
 593         /*
 594          * Don't do destructive transforms as protocol code does
 595          * '[]' unwrapping in get_host_and_port()
 596          */
 597         if (host[0] == '[') {
 598                 end = strchr(host + 1, ']');
 599                 if (end) {
 600                         end++;
 601                 } else
 602                         end = host;
 603         } else
 604                 end = host;
 605
 606         if (protocol == PROTO_LOCAL)
 607                 path = end;
 608         else if (protocol == PROTO_FILE && has_dos_drive_prefix(end))
 609                 path = end; /* "file://$(pwd)" may be "file://C:/projects/repo" */
 610         else
 611                 path = strchr(end, separator);
 612
 613         if (!path || !*path)
 614                 die("No path specified. See 'man git-pull' for valid url syntax");
 615
 616         /*
 617          * null-terminate hostname and point path to ~ for URL's like this:
 618          *    ssh://host.xz/~user/repo
 619          */
 620
 621         end = path; /* Need to \0 terminate host here */
 622         if (separator == ':')
 623                 path++; /* path starts after ':' */
 624         if (protocol == PROTO_GIT || protocol == PROTO_SSH) {
 625                 if (path[1] == '~')
 626                         path++;
 627         }
 628
 629         path = xstrdup(path);
 630         *end = '\0';
 631
 632         *ret_host = xstrdup(host);
 633         *ret_path = path;
 634         free(url);
 635         return protocol;
 636 }
 637
 638 static struct child_process no_fork = CHILD_PROCESS_INIT;
 639
 640 /*
 641  * This returns a dummy child_process if the transport protocol does not
 642  * need fork(2), or a struct child_process object if it does.  Once done,
 643  * finish the connection with finish_connect() with the value returned from
 644  * this function (it is safe to call finish_connect() with NULL to support
 645  * the former case).
 646  *
 647  * If it returns, the connect is successful; it just dies on errors (this
 648  * will hopefully be changed in a libification effort, to return NULL when
 649  * the connection failed).
 650  */
 651 struct child_process *git_connect(int fd[2], const char *url,
 652                                   const char *prog, int flags)
 653 {
 654         char *hostandport, *path;
 655         struct child_process *conn = &no_fork;
 656         enum protocol protocol;
 657         struct strbuf cmd = STRBUF_INIT;
 658
 659         /* Without this we cannot rely on waitpid() to tell
 660          * what happened to our children.
 661          */
 662         signal(SIGCHLD, SIG_DFL);
 663
 664         protocol = parse_connect_url(url, &hostandport, &path);
 665         if (flags & CONNECT_DIAG_URL) {
 666                 printf("Diag: url=%s\n", url ? url : "NULL");
 667                 printf("Diag: protocol=%s\n", prot_name(protocol));
 668                 printf("Diag: hostandport=%s\n", hostandport ? hostandport : "NULL");
 669                 printf("Diag: path=%s\n", path ? path : "NULL");
 670                 conn = NULL;
 671         } else if (protocol == PROTO_GIT) {
 672                 /*
 673                  * Set up virtual host information based on where we will
 674                  * connect, unless the user has overridden us in
 675                  * the environment.
 676                  */
 677                 char *target_host = getenv("GIT_OVERRIDE_VIRTUAL_HOST");
 678                 if (target_host)
 679                         target_host = xstrdup(target_host);
 680                 else
 681                         target_host = xstrdup(hostandport);
 682
 683                 /* These underlying connection commands die() if they
 684                  * cannot connect.
 685                  */
 686                 if (git_use_proxy(hostandport))
 687                         conn = git_proxy_connect(fd, hostandport);
 688                 else
 689                         git_tcp_connect(fd, hostandport, flags);
 690                 /*
 691                  * Separate original protocol components prog and path
 692                  * from extended host header with a NUL byte.
 693                  *
 694                  * Note: Do not add any other headers here!  Doing so
 695                  * will cause older git-daemon servers to crash.
 696                  */
 697                 packet_write(fd[1],
 698                              "%s %s%chost=%s%c",
 699                              prog, path, 0,
 700                              target_host, 0);
 701                 free(target_host);
 702         } else {
 703                 conn = xmalloc(sizeof(*conn));
 704                 child_process_init(conn);
 705
 706                 strbuf_addstr(&cmd, prog);
 707                 strbuf_addch(&cmd, ' ');
 708                 sq_quote_buf(&cmd, path);
 709
 710                 conn->in = conn->out = -1;
 711                 if (protocol == PROTO_SSH) {
 712                         const char *ssh;
 713                         int putty;
 714                         char *ssh_host = hostandport;
 715                         const char *port = NULL;
 716                         get_host_and_port(&ssh_host, &port);
 717                         port = get_port_numeric(port);
 718
 719                         ssh = getenv("GIT_SSH_COMMAND");
 720                         if (ssh) {
 721                                 conn->use_shell = 1;
 722                                 putty = 0;
 723                         } else {
 724                                 ssh = getenv("GIT_SSH");
 725                                 if (!ssh)
 726                                         ssh = "ssh";
 727                                 putty = !!strcasestr(ssh, "plink");
 728                         }
 729
 730                         argv_array_push(&conn->args, ssh);
 731                         if (putty && !strcasestr(ssh, "tortoiseplink"))
 732                                 argv_array_push(&conn->args, "-batch");
 733                         if (port) {
 734                                 /* P is for PuTTY, p is for OpenSSH */
 735                                 argv_array_push(&conn->args, putty ? "-P" : "-p");
 736                                 argv_array_push(&conn->args, port);
 737                         }
 738                         argv_array_push(&conn->args, ssh_host);
 739                 } else {
 740                         /* remove repo-local variables from the environment */
 741                         conn->env = local_repo_env;
 742                         conn->use_shell = 1;
 743                 }
 744                 argv_array_push(&conn->args, cmd.buf);
 745
 746                 if (start_command(conn))
 747                         die("unable to fork");
 748
 749                 fd[0] = conn->out; /* read from child's stdout */
 750                 fd[1] = conn->in;  /* write to child's stdin */
 751                 strbuf_release(&cmd);
 752         }
 753         free(hostandport);
 754         free(path);
 755         return conn;
 756 }
 757
 758 int git_connection_is_socket(struct child_process *conn)
 759 {
 760         return conn == &no_fork;
 761 }
 762
 763 int finish_connect(struct child_process *conn)
 764 {
 765         int code;
 766         if (!conn || git_connection_is_socket(conn))
 767                 return 0;
 768
 769         code = finish_command(conn);
 770         free(conn);
 771         return code;
 772 }