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, int len, unsigned int flags)
  17 {
  18         if (!flags)
  19                 return 1;
  20
  21         if (len < 5 || memcmp(name, "refs/", 5))
  22                 return 0;
  23
  24         /* Skip the "refs/" part */
  25         name += 5;
  26         len -= 5;
  27
  28         /* REF_NORMAL means that we don't want the magic fake tag refs */
  29         if ((flags & REF_NORMAL) && check_refname_format(name, 0))
  30                 return 0;
  31
  32         /* REF_HEADS means that we want regular branch heads */
  33         if ((flags & REF_HEADS) && !memcmp(name, "heads/", 6))
  34                 return 1;
  35
  36         /* REF_TAGS means that we want tags */
  37         if ((flags & REF_TAGS) && !memcmp(name, "tags/", 5))
  38                 return 1;
  39
  40         /* All type bits clear means that we are ok with anything */
  41         return !(flags & ~REF_NORMAL);
  42 }
  43
  44 int check_ref_type(const struct ref *ref, int flags)
  45 {
  46         return check_ref(ref->name, strlen(ref->name), flags);
  47 }
  48
  49 static void die_initial_contact(int got_at_least_one_head)
  50 {
  51         if (got_at_least_one_head)
  52                 die("The remote end hung up upon initial contact");
  53         else
  54                 die("Could not read from remote repository.\n\n"
  55                     "Please make sure you have the correct access rights\n"
  56                     "and the repository exists.");
  57 }
  58
  59 static void parse_one_symref_info(struct string_list *symref, const char *val, int len)
  60 {
  61         char *sym, *target;
  62         struct string_list_item *item;
  63
  64         if (!len)
  65                 return; /* just "symref" */
  66         /* e.g. "symref=HEAD:refs/heads/master" */
  67         sym = xmalloc(len + 1);
  68         memcpy(sym, val, len);
  69         sym[len] = '\0';
  70         target = strchr(sym, ':');
  71         if (!target)
  72                 /* just "symref=something" */
  73                 goto reject;
  74         *(target++) = '\0';
  75         if (check_refname_format(sym, REFNAME_ALLOW_ONELEVEL) ||
  76             check_refname_format(target, REFNAME_ALLOW_ONELEVEL))
  77                 /* "symref=bogus:pair */
  78                 goto reject;
  79         item = string_list_append(symref, sym);
  80         item->util = target;
  81         return;
  82 reject:
  83         free(sym);
  84         return;
  85 }
  86
  87 static void annotate_refs_with_symref_info(struct ref *ref)
  88 {
  89         struct string_list symref = STRING_LIST_INIT_DUP;
  90         const char *feature_list = server_capabilities;
  91
  92         while (feature_list) {
  93                 int len;
  94                 const char *val;
  95
  96                 val = parse_feature_value(feature_list, "symref", &len);
  97                 if (!val)
  98                         break;
  99                 parse_one_symref_info(&symref, val, len);
 100                 feature_list = val + 1;
 101         }
 102         sort_string_list(&symref);
 103
 104         for (; ref; ref = ref->next) {
 105                 struct string_list_item *item;
 106                 item = string_list_lookup(&symref, ref->name);
 107                 if (!item)
 108                         continue;
 109                 ref->symref = xstrdup((char *)item->util);
 110         }
 111         string_list_clear(&symref, 0);
 112 }
 113
 114 /*
 115  * Read all the refs from the other end
 116  */
 117 struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
 118                               struct ref **list, unsigned int flags,
 119                               struct sha1_array *extra_have,
 120                               struct sha1_array *shallow_points)
 121 {
 122         struct ref **orig_list = list;
 123         int got_at_least_one_head = 0;
 124
 125         *list = NULL;
 126         for (;;) {
 127                 struct ref *ref;
 128                 unsigned char old_sha1[20];
 129                 char *name;
 130                 int len, name_len;
 131                 char *buffer = packet_buffer;
 132
 133                 len = packet_read(in, &src_buf, &src_len,
 134                                   packet_buffer, sizeof(packet_buffer),
 135                                   PACKET_READ_GENTLE_ON_EOF |
 136                                   PACKET_READ_CHOMP_NEWLINE);
 137                 if (len < 0)
 138                         die_initial_contact(got_at_least_one_head);
 139
 140                 if (!len)
 141                         break;
 142
 143                 if (len > 4 && starts_with(buffer, "ERR "))
 144                         die("remote error: %s", buffer + 4);
 145
 146                 if (len == 48 && starts_with(buffer, "shallow ")) {
 147                         if (get_sha1_hex(buffer + 8, old_sha1))
 148                                 die("protocol error: expected shallow sha-1, got '%s'", buffer + 8);
 149                         if (!shallow_points)
 150                                 die("repository on the other end cannot be shallow");
 151                         sha1_array_append(shallow_points, old_sha1);
 152                         continue;
 153                 }
 154
 155                 if (len < 42 || get_sha1_hex(buffer, old_sha1) || buffer[40] != ' ')
 156                         die("protocol error: expected sha/ref, got '%s'", buffer);
 157                 name = buffer + 41;
 158
 159                 name_len = strlen(name);
 160                 if (len != name_len + 41) {
 161                         free(server_capabilities);
 162                         server_capabilities = xstrdup(name + name_len + 1);
 163                 }
 164
 165                 if (extra_have &&
 166                     name_len == 5 && !memcmp(".have", name, 5)) {
 167                         sha1_array_append(extra_have, old_sha1);
 168                         continue;
 169                 }
 170
 171                 if (!check_ref(name, name_len, flags))
 172                         continue;
 173                 ref = alloc_ref(buffer + 41);
 174                 hashcpy(ref->old_sha1, old_sha1);
 175                 *list = ref;
 176                 list = &ref->next;
 177                 got_at_least_one_head = 1;
 178         }
 179
 180         annotate_refs_with_symref_info(*orig_list);
 181
 182         return list;
 183 }
 184
 185 static const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
 186 {
 187         int len;
 188
 189         if (!feature_list)
 190                 return NULL;
 191
 192         len = strlen(feature);
 193         while (*feature_list) {
 194                 const char *found = strstr(feature_list, feature);
 195                 if (!found)
 196                         return NULL;
 197                 if (feature_list == found || isspace(found[-1])) {
 198                         const char *value = found + len;
 199                         /* feature with no value (e.g., "thin-pack") */
 200                         if (!*value || isspace(*value)) {
 201                                 if (lenp)
 202                                         *lenp = 0;
 203                                 return value;
 204                         }
 205                         /* feature with a value (e.g., "agent=git/1.2.3") */
 206                         else if (*value == '=') {
 207                                 value++;
 208                                 if (lenp)
 209                                         *lenp = strcspn(value, " \t\n");
 210                                 return value;
 211                         }
 212                         /*
 213                          * otherwise we matched a substring of another feature;
 214                          * keep looking
 215                          */
 216                 }
 217                 feature_list = found + 1;
 218         }
 219         return NULL;
 220 }
 221
 222 int parse_feature_request(const char *feature_list, const char *feature)
 223 {
 224         return !!parse_feature_value(feature_list, feature, NULL);
 225 }
 226
 227 const char *server_feature_value(const char *feature, int *len)
 228 {
 229         return parse_feature_value(server_capabilities, feature, len);
 230 }
 231
 232 int server_supports(const char *feature)
 233 {
 234         return !!server_feature_value(feature, NULL);
 235 }
 236
 237 enum protocol {
 238         PROTO_LOCAL = 1,
 239         PROTO_FILE,
 240         PROTO_SSH,
 241         PROTO_GIT
 242 };
 243
 244 int url_is_local_not_ssh(const char *url)
 245 {
 246         const char *colon = strchr(url, ':');
 247         const char *slash = strchr(url, '/');
 248         return !colon || (slash && slash < colon) ||
 249                 has_dos_drive_prefix(url);
 250 }
 251
 252 static const char *prot_name(enum protocol protocol)
 253 {
 254         switch (protocol) {
 255                 case PROTO_LOCAL:
 256                 case PROTO_FILE:
 257                         return "file";
 258                 case PROTO_SSH:
 259                         return "ssh";
 260                 case PROTO_GIT:
 261                         return "git";
 262                 default:
 263                         return "unkown protocol";
 264         }
 265 }
 266
 267 static enum protocol get_protocol(const char *name)
 268 {
 269         if (!strcmp(name, "ssh"))
 270                 return PROTO_SSH;
 271         if (!strcmp(name, "git"))
 272                 return PROTO_GIT;
 273         if (!strcmp(name, "git+ssh"))
 274                 return PROTO_SSH;
 275         if (!strcmp(name, "ssh+git"))
 276                 return PROTO_SSH;
 277         if (!strcmp(name, "file"))
 278                 return PROTO_FILE;
 279         die("I don't handle protocol '%s'", name);
 280 }
 281
 282 #define STR_(s) # s
 283 #define STR(s)  STR_(s)
 284
 285 static void get_host_and_port(char **host, const char **port)
 286 {
 287         char *colon, *end;
 288
 289         if (*host[0] == '[') {
 290                 end = strchr(*host + 1, ']');
 291                 if (end) {
 292                         *end = 0;
 293                         end++;
 294                         (*host)++;
 295                 } else
 296                         end = *host;
 297         } else
 298                 end = *host;
 299         colon = strchr(end, ':');
 300
 301         if (colon) {
 302                 *colon = 0;
 303                 *port = colon + 1;
 304         }
 305 }
 306
 307 static void enable_keepalive(int sockfd)
 308 {
 309         int ka = 1;
 310
 311         if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
 312                 fprintf(stderr, "unable to set SO_KEEPALIVE on socket: %s\n",
 313                         strerror(errno));
 314 }
 315
 316 #ifndef NO_IPV6
 317
 318 static const char *ai_name(const struct addrinfo *ai)
 319 {
 320         static char addr[NI_MAXHOST];
 321         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
 322                         NI_NUMERICHOST) != 0)
 323                 strcpy(addr, "(unknown)");
 324
 325         return addr;
 326 }
 327
 328 /*
 329  * Returns a connected socket() fd, or else die()s.
 330  */
 331 static int git_tcp_connect_sock(char *host, int flags)
 332 {
 333         struct strbuf error_message = STRBUF_INIT;
 334         int sockfd = -1;
 335         const char *port = STR(DEFAULT_GIT_PORT);
 336         struct addrinfo hints, *ai0, *ai;
 337         int gai;
 338         int cnt = 0;
 339
 340         get_host_and_port(&host, &port);
 341         if (!*port)
 342                 port = "<none>";
 343
 344         memset(&hints, 0, sizeof(hints));
 345         hints.ai_socktype = SOCK_STREAM;
 346         hints.ai_protocol = IPPROTO_TCP;
 347
 348         if (flags & CONNECT_VERBOSE)
 349                 fprintf(stderr, "Looking up %s ... ", host);
 350
 351         gai = getaddrinfo(host, port, &hints, &ai);
 352         if (gai)
 353                 die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
 354
 355         if (flags & CONNECT_VERBOSE)
 356                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 357
 358         for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
 359                 sockfd = socket(ai->ai_family,
 360                                 ai->ai_socktype, ai->ai_protocol);
 361                 if ((sockfd < 0) ||
 362                     (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
 363                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 364                                     host, cnt, ai_name(ai), strerror(errno));
 365                         if (0 <= sockfd)
 366                                 close(sockfd);
 367                         sockfd = -1;
 368                         continue;
 369                 }
 370                 if (flags & CONNECT_VERBOSE)
 371                         fprintf(stderr, "%s ", ai_name(ai));
 372                 break;
 373         }
 374
 375         freeaddrinfo(ai0);
 376
 377         if (sockfd < 0)
 378                 die("unable to connect to %s:\n%s", host, error_message.buf);
 379
 380         enable_keepalive(sockfd);
 381
 382         if (flags & CONNECT_VERBOSE)
 383                 fprintf(stderr, "done.\n");
 384
 385         strbuf_release(&error_message);
 386
 387         return sockfd;
 388 }
 389
 390 #else /* NO_IPV6 */
 391
 392 /*
 393  * Returns a connected socket() fd, or else die()s.
 394  */
 395 static int git_tcp_connect_sock(char *host, int flags)
 396 {
 397         struct strbuf error_message = STRBUF_INIT;
 398         int sockfd = -1;
 399         const char *port = STR(DEFAULT_GIT_PORT);
 400         char *ep;
 401         struct hostent *he;
 402         struct sockaddr_in sa;
 403         char **ap;
 404         unsigned int nport;
 405         int cnt;
 406
 407         get_host_and_port(&host, &port);
 408
 409         if (flags & CONNECT_VERBOSE)
 410                 fprintf(stderr, "Looking up %s ... ", host);
 411
 412         he = gethostbyname(host);
 413         if (!he)
 414                 die("Unable to look up %s (%s)", host, hstrerror(h_errno));
 415         nport = strtoul(port, &ep, 10);
 416         if ( ep == port || *ep ) {
 417                 /* Not numeric */
 418                 struct servent *se = getservbyname(port,"tcp");
 419                 if ( !se )
 420                         die("Unknown port %s", port);
 421                 nport = se->s_port;
 422         }
 423
 424         if (flags & CONNECT_VERBOSE)
 425                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 426
 427         for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
 428                 memset(&sa, 0, sizeof sa);
 429                 sa.sin_family = he->h_addrtype;
 430                 sa.sin_port = htons(nport);
 431                 memcpy(&sa.sin_addr, *ap, he->h_length);
 432
 433                 sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 434                 if ((sockfd < 0) ||
 435                     connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 436                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 437                                 host,
 438                                 cnt,
 439                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr),
 440                                 strerror(errno));
 441                         if (0 <= sockfd)
 442                                 close(sockfd);
 443                         sockfd = -1;
 444                         continue;
 445                 }
 446                 if (flags & CONNECT_VERBOSE)
 447                         fprintf(stderr, "%s ",
 448                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr));
 449                 break;
 450         }
 451
 452         if (sockfd < 0)
 453                 die("unable to connect to %s:\n%s", host, error_message.buf);
 454
 455         enable_keepalive(sockfd);
 456
 457         if (flags & CONNECT_VERBOSE)
 458                 fprintf(stderr, "done.\n");
 459
 460         return sockfd;
 461 }
 462
 463 #endif /* NO_IPV6 */
 464
 465
 466 static void git_tcp_connect(int fd[2], char *host, int flags)
 467 {
 468         int sockfd = git_tcp_connect_sock(host, flags);
 469
 470         fd[0] = sockfd;
 471         fd[1] = dup(sockfd);
 472 }
 473
 474
 475 static char *git_proxy_command;
 476
 477 static int git_proxy_command_options(const char *var, const char *value,
 478                 void *cb)
 479 {
 480         if (!strcmp(var, "core.gitproxy")) {
 481                 const char *for_pos;
 482                 int matchlen = -1;
 483                 int hostlen;
 484                 const char *rhost_name = cb;
 485                 int rhost_len = strlen(rhost_name);
 486
 487                 if (git_proxy_command)
 488                         return 0;
 489                 if (!value)
 490                         return config_error_nonbool(var);
 491                 /* [core]
 492                  * ;# matches www.kernel.org as well
 493                  * gitproxy = netcatter-1 for kernel.org
 494                  * gitproxy = netcatter-2 for sample.xz
 495                  * gitproxy = netcatter-default
 496                  */
 497                 for_pos = strstr(value, " for ");
 498                 if (!for_pos)
 499                         /* matches everybody */
 500                         matchlen = strlen(value);
 501                 else {
 502                         hostlen = strlen(for_pos + 5);
 503                         if (rhost_len < hostlen)
 504                                 matchlen = -1;
 505                         else if (!strncmp(for_pos + 5,
 506                                           rhost_name + rhost_len - hostlen,
 507                                           hostlen) &&
 508                                  ((rhost_len == hostlen) ||
 509                                   rhost_name[rhost_len - hostlen -1] == '.'))
 510                                 matchlen = for_pos - value;
 511                         else
 512                                 matchlen = -1;
 513                 }
 514                 if (0 <= matchlen) {
 515                         /* core.gitproxy = none for kernel.org */
 516                         if (matchlen == 4 &&
 517                             !memcmp(value, "none", 4))
 518                                 matchlen = 0;
 519                         git_proxy_command = xmemdupz(value, matchlen);
 520                 }
 521                 return 0;
 522         }
 523
 524         return git_default_config(var, value, cb);
 525 }
 526
 527 static int git_use_proxy(const char *host)
 528 {
 529         git_proxy_command = getenv("GIT_PROXY_COMMAND");
 530         git_config(git_proxy_command_options, (void*)host);
 531         return (git_proxy_command && *git_proxy_command);
 532 }
 533
 534 static struct child_process *git_proxy_connect(int fd[2], char *host)
 535 {
 536         const char *port = STR(DEFAULT_GIT_PORT);
 537         const char **argv;
 538         struct child_process *proxy;
 539
 540         get_host_and_port(&host, &port);
 541
 542         argv = xmalloc(sizeof(*argv) * 4);
 543         argv[0] = git_proxy_command;
 544         argv[1] = host;
 545         argv[2] = port;
 546         argv[3] = NULL;
 547         proxy = xcalloc(1, sizeof(*proxy));
 548         proxy->argv = argv;
 549         proxy->in = -1;
 550         proxy->out = -1;
 551         if (start_command(proxy))
 552                 die("cannot start proxy %s", argv[0]);
 553         fd[0] = proxy->out; /* read from proxy stdout */
 554         fd[1] = proxy->in;  /* write to proxy stdin */
 555         return proxy;
 556 }
 557
 558 static const char *get_port_numeric(const char *p)
 559 {
 560         char *end;
 561         if (p) {
 562                 long port = strtol(p + 1, &end, 10);
 563                 if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
 564                         return p;
 565                 }
 566         }
 567
 568         return NULL;
 569 }
 570
 571 /*
 572  * Extract protocol and relevant parts from the specified connection URL.
 573  * The caller must free() the returned strings.
 574  */
 575 static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
 576                                        char **ret_path)
 577 {
 578         char *url;
 579         char *host, *path;
 580         char *end;
 581         int separator = '/';
 582         enum protocol protocol = PROTO_LOCAL;
 583
 584         if (is_url(url_orig))
 585                 url = url_decode(url_orig);
 586         else
 587                 url = xstrdup(url_orig);
 588
 589         host = strstr(url, "://");
 590         if (host) {
 591                 *host = '\0';
 592                 protocol = get_protocol(url);
 593                 host += 3;
 594         } else {
 595                 host = url;
 596                 if (!url_is_local_not_ssh(url)) {
 597                         protocol = PROTO_SSH;
 598                         separator = ':';
 599                 }
 600         }
 601
 602         /*
 603          * Don't do destructive transforms as protocol code does
 604          * '[]' unwrapping in get_host_and_port()
 605          */
 606         if (host[0] == '[') {
 607                 end = strchr(host + 1, ']');
 608                 if (end) {
 609                         end++;
 610                 } else
 611                         end = host;
 612         } else
 613                 end = host;
 614
 615         if (protocol == PROTO_LOCAL)
 616                 path = end;
 617         else if (protocol == PROTO_FILE && has_dos_drive_prefix(end))
 618                 path = end; /* "file://$(pwd)" may be "file://C:/projects/repo" */
 619         else
 620                 path = strchr(end, separator);
 621
 622         if (!path || !*path)
 623                 die("No path specified. See 'man git-pull' for valid url syntax");
 624
 625         /*
 626          * null-terminate hostname and point path to ~ for URL's like this:
 627          *    ssh://host.xz/~user/repo
 628          */
 629
 630         end = path; /* Need to \0 terminate host here */
 631         if (separator == ':')
 632                 path++; /* path starts after ':' */
 633         if (protocol == PROTO_GIT || protocol == PROTO_SSH) {
 634                 if (path[1] == '~')
 635                         path++;
 636         }
 637
 638         path = xstrdup(path);
 639         *end = '\0';
 640
 641         *ret_host = xstrdup(host);
 642         *ret_path = path;
 643         free(url);
 644         return protocol;
 645 }
 646
 647 static struct child_process no_fork;
 648
 649 /*
 650  * This returns a dummy child_process if the transport protocol does not
 651  * need fork(2), or a struct child_process object if it does.  Once done,
 652  * finish the connection with finish_connect() with the value returned from
 653  * this function (it is safe to call finish_connect() with NULL to support
 654  * the former case).
 655  *
 656  * If it returns, the connect is successful; it just dies on errors (this
 657  * will hopefully be changed in a libification effort, to return NULL when
 658  * the connection failed).
 659  */
 660 struct child_process *git_connect(int fd[2], const char *url,
 661                                   const char *prog, int flags)
 662 {
 663         char *hostandport, *path;
 664         struct child_process *conn = &no_fork;
 665         enum protocol protocol;
 666         const char **arg;
 667         struct strbuf cmd = STRBUF_INIT;
 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         protocol = parse_connect_url(url, &hostandport, &path);
 675         if (flags & CONNECT_DIAG_URL) {
 676                 printf("Diag: url=%s\n", url ? url : "NULL");
 677                 printf("Diag: protocol=%s\n", prot_name(protocol));
 678                 printf("Diag: hostandport=%s\n", hostandport ? hostandport : "NULL");
 679                 printf("Diag: path=%s\n", path ? path : "NULL");
 680                 conn = NULL;
 681         } else if (protocol == PROTO_GIT) {
 682                 /* These underlying connection commands die() if they
 683                  * cannot connect.
 684                  */
 685                 char *target_host = xstrdup(hostandport);
 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 = xcalloc(1, sizeof(*conn));
 704
 705                 strbuf_addstr(&cmd, prog);
 706                 strbuf_addch(&cmd, ' ');
 707                 sq_quote_buf(&cmd, path);
 708
 709                 conn->in = conn->out = -1;
 710                 conn->argv = arg = xcalloc(7, sizeof(*arg));
 711                 if (protocol == PROTO_SSH) {
 712                         const char *ssh = getenv("GIT_SSH");
 713                         int putty = ssh && strcasestr(ssh, "plink");
 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                         if (!ssh) ssh = "ssh";
 720
 721                         *arg++ = ssh;
 722                         if (putty && !strcasestr(ssh, "tortoiseplink"))
 723                                 *arg++ = "-batch";
 724                         if (port) {
 725                                 /* P is for PuTTY, p is for OpenSSH */
 726                                 *arg++ = putty ? "-P" : "-p";
 727                                 *arg++ = port;
 728                         }
 729                         *arg++ = ssh_host;
 730                 } else {
 731                         /* remove repo-local variables from the environment */
 732                         conn->env = local_repo_env;
 733                         conn->use_shell = 1;
 734                 }
 735                 *arg++ = cmd.buf;
 736                 *arg = NULL;
 737
 738                 if (start_command(conn))
 739                         die("unable to fork");
 740
 741                 fd[0] = conn->out; /* read from child's stdout */
 742                 fd[1] = conn->in;  /* write to child's stdin */
 743                 strbuf_release(&cmd);
 744         }
 745         free(hostandport);
 746         free(path);
 747         return conn;
 748 }
 749
 750 int git_connection_is_socket(struct child_process *conn)
 751 {
 752         return conn == &no_fork;
 753 }
 754
 755 int finish_connect(struct child_process *conn)
 756 {
 757         int code;
 758         if (!conn || git_connection_is_socket(conn))
 759                 return 0;
 760
 761         code = finish_command(conn);
 762         free(conn->argv);
 763         free(conn);
 764         return code;
 765 }