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 static char *host_end(char **hoststart, int removebrackets)
 277 {
 278         char *host = *hoststart;
 279         char *end;
 280         char *start = strstr(host, "@[");
 281         if (start)
 282                 start++; /* Jump over '@' */
 283         else
 284                 start = host;
 285         if (start[0] == '[') {
 286                 end = strchr(start + 1, ']');
 287                 if (end) {
 288                         if (removebrackets) {
 289                                 *end = 0;
 290                                 memmove(start, start + 1, end - start);
 291                                 end++;
 292                         }
 293                 } else
 294                         end = host;
 295         } else
 296                 end = host;
 297         return end;
 298 }
 299
 300 #define STR_(s) # s
 301 #define STR(s)  STR_(s)
 302
 303 static void get_host_and_port(char **host, const char **port)
 304 {
 305         char *colon, *end;
 306         end = host_end(host, 1);
 307         colon = strchr(end, ':');
 308         if (colon) {
 309                 long portnr = strtol(colon + 1, &end, 10);
 310                 if (end != colon + 1 && *end == '\0' && 0 <= portnr && portnr < 65536) {
 311                         *colon = 0;
 312                         *port = colon + 1;
 313                 }
 314         }
 315 }
 316
 317 static void enable_keepalive(int sockfd)
 318 {
 319         int ka = 1;
 320
 321         if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
 322                 fprintf(stderr, "unable to set SO_KEEPALIVE on socket: %s\n",
 323                         strerror(errno));
 324 }
 325
 326 #ifndef NO_IPV6
 327
 328 static const char *ai_name(const struct addrinfo *ai)
 329 {
 330         static char addr[NI_MAXHOST];
 331         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
 332                         NI_NUMERICHOST) != 0)
 333                 strcpy(addr, "(unknown)");
 334
 335         return addr;
 336 }
 337
 338 /*
 339  * Returns a connected socket() fd, or else die()s.
 340  */
 341 static int git_tcp_connect_sock(char *host, int flags)
 342 {
 343         struct strbuf error_message = STRBUF_INIT;
 344         int sockfd = -1;
 345         const char *port = STR(DEFAULT_GIT_PORT);
 346         struct addrinfo hints, *ai0, *ai;
 347         int gai;
 348         int cnt = 0;
 349
 350         get_host_and_port(&host, &port);
 351         if (!*port)
 352                 port = "<none>";
 353
 354         memset(&hints, 0, sizeof(hints));
 355         hints.ai_socktype = SOCK_STREAM;
 356         hints.ai_protocol = IPPROTO_TCP;
 357
 358         if (flags & CONNECT_VERBOSE)
 359                 fprintf(stderr, "Looking up %s ... ", host);
 360
 361         gai = getaddrinfo(host, port, &hints, &ai);
 362         if (gai)
 363                 die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
 364
 365         if (flags & CONNECT_VERBOSE)
 366                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 367
 368         for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
 369                 sockfd = socket(ai->ai_family,
 370                                 ai->ai_socktype, ai->ai_protocol);
 371                 if ((sockfd < 0) ||
 372                     (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
 373                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 374                                     host, cnt, ai_name(ai), strerror(errno));
 375                         if (0 <= sockfd)
 376                                 close(sockfd);
 377                         sockfd = -1;
 378                         continue;
 379                 }
 380                 if (flags & CONNECT_VERBOSE)
 381                         fprintf(stderr, "%s ", ai_name(ai));
 382                 break;
 383         }
 384
 385         freeaddrinfo(ai0);
 386
 387         if (sockfd < 0)
 388                 die("unable to connect to %s:\n%s", host, error_message.buf);
 389
 390         enable_keepalive(sockfd);
 391
 392         if (flags & CONNECT_VERBOSE)
 393                 fprintf(stderr, "done.\n");
 394
 395         strbuf_release(&error_message);
 396
 397         return sockfd;
 398 }
 399
 400 #else /* NO_IPV6 */
 401
 402 /*
 403  * Returns a connected socket() fd, or else die()s.
 404  */
 405 static int git_tcp_connect_sock(char *host, int flags)
 406 {
 407         struct strbuf error_message = STRBUF_INIT;
 408         int sockfd = -1;
 409         const char *port = STR(DEFAULT_GIT_PORT);
 410         char *ep;
 411         struct hostent *he;
 412         struct sockaddr_in sa;
 413         char **ap;
 414         unsigned int nport;
 415         int cnt;
 416
 417         get_host_and_port(&host, &port);
 418
 419         if (flags & CONNECT_VERBOSE)
 420                 fprintf(stderr, "Looking up %s ... ", host);
 421
 422         he = gethostbyname(host);
 423         if (!he)
 424                 die("Unable to look up %s (%s)", host, hstrerror(h_errno));
 425         nport = strtoul(port, &ep, 10);
 426         if ( ep == port || *ep ) {
 427                 /* Not numeric */
 428                 struct servent *se = getservbyname(port,"tcp");
 429                 if ( !se )
 430                         die("Unknown port %s", port);
 431                 nport = se->s_port;
 432         }
 433
 434         if (flags & CONNECT_VERBOSE)
 435                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 436
 437         for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
 438                 memset(&sa, 0, sizeof sa);
 439                 sa.sin_family = he->h_addrtype;
 440                 sa.sin_port = htons(nport);
 441                 memcpy(&sa.sin_addr, *ap, he->h_length);
 442
 443                 sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 444                 if ((sockfd < 0) ||
 445                     connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 446                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 447                                 host,
 448                                 cnt,
 449                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr),
 450                                 strerror(errno));
 451                         if (0 <= sockfd)
 452                                 close(sockfd);
 453                         sockfd = -1;
 454                         continue;
 455                 }
 456                 if (flags & CONNECT_VERBOSE)
 457                         fprintf(stderr, "%s ",
 458                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr));
 459                 break;
 460         }
 461
 462         if (sockfd < 0)
 463                 die("unable to connect to %s:\n%s", host, error_message.buf);
 464
 465         enable_keepalive(sockfd);
 466
 467         if (flags & CONNECT_VERBOSE)
 468                 fprintf(stderr, "done.\n");
 469
 470         return sockfd;
 471 }
 472
 473 #endif /* NO_IPV6 */
 474
 475
 476 static void git_tcp_connect(int fd[2], char *host, int flags)
 477 {
 478         int sockfd = git_tcp_connect_sock(host, flags);
 479
 480         fd[0] = sockfd;
 481         fd[1] = dup(sockfd);
 482 }
 483
 484
 485 static char *git_proxy_command;
 486
 487 static int git_proxy_command_options(const char *var, const char *value,
 488                 void *cb)
 489 {
 490         if (!strcmp(var, "core.gitproxy")) {
 491                 const char *for_pos;
 492                 int matchlen = -1;
 493                 int hostlen;
 494                 const char *rhost_name = cb;
 495                 int rhost_len = strlen(rhost_name);
 496
 497                 if (git_proxy_command)
 498                         return 0;
 499                 if (!value)
 500                         return config_error_nonbool(var);
 501                 /* [core]
 502                  * ;# matches www.kernel.org as well
 503                  * gitproxy = netcatter-1 for kernel.org
 504                  * gitproxy = netcatter-2 for sample.xz
 505                  * gitproxy = netcatter-default
 506                  */
 507                 for_pos = strstr(value, " for ");
 508                 if (!for_pos)
 509                         /* matches everybody */
 510                         matchlen = strlen(value);
 511                 else {
 512                         hostlen = strlen(for_pos + 5);
 513                         if (rhost_len < hostlen)
 514                                 matchlen = -1;
 515                         else if (!strncmp(for_pos + 5,
 516                                           rhost_name + rhost_len - hostlen,
 517                                           hostlen) &&
 518                                  ((rhost_len == hostlen) ||
 519                                   rhost_name[rhost_len - hostlen -1] == '.'))
 520                                 matchlen = for_pos - value;
 521                         else
 522                                 matchlen = -1;
 523                 }
 524                 if (0 <= matchlen) {
 525                         /* core.gitproxy = none for kernel.org */
 526                         if (matchlen == 4 &&
 527                             !memcmp(value, "none", 4))
 528                                 matchlen = 0;
 529                         git_proxy_command = xmemdupz(value, matchlen);
 530                 }
 531                 return 0;
 532         }
 533
 534         return git_default_config(var, value, cb);
 535 }
 536
 537 static int git_use_proxy(const char *host)
 538 {
 539         git_proxy_command = getenv("GIT_PROXY_COMMAND");
 540         git_config(git_proxy_command_options, (void*)host);
 541         return (git_proxy_command && *git_proxy_command);
 542 }
 543
 544 static struct child_process *git_proxy_connect(int fd[2], char *host)
 545 {
 546         const char *port = STR(DEFAULT_GIT_PORT);
 547         struct child_process *proxy;
 548
 549         get_host_and_port(&host, &port);
 550
 551         proxy = xmalloc(sizeof(*proxy));
 552         child_process_init(proxy);
 553         argv_array_push(&proxy->args, git_proxy_command);
 554         argv_array_push(&proxy->args, host);
 555         argv_array_push(&proxy->args, port);
 556         proxy->in = -1;
 557         proxy->out = -1;
 558         if (start_command(proxy))
 559                 die("cannot start proxy %s", git_proxy_command);
 560         fd[0] = proxy->out; /* read from proxy stdout */
 561         fd[1] = proxy->in;  /* write to proxy stdin */
 562         return proxy;
 563 }
 564
 565 static char *get_port(char *host)
 566 {
 567         char *end;
 568         char *p = strchr(host, ':');
 569
 570         if (p) {
 571                 long port = strtol(p + 1, &end, 10);
 572                 if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
 573                         *p = '\0';
 574                         return p+1;
 575                 }
 576         }
 577
 578         return NULL;
 579 }
 580
 581 /*
 582  * Extract protocol and relevant parts from the specified connection URL.
 583  * The caller must free() the returned strings.
 584  */
 585 static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
 586                                        char **ret_path)
 587 {
 588         char *url;
 589         char *host, *path;
 590         char *end;
 591         int separator = '/';
 592         enum protocol protocol = PROTO_LOCAL;
 593
 594         if (is_url(url_orig))
 595                 url = url_decode(url_orig);
 596         else
 597                 url = xstrdup(url_orig);
 598
 599         host = strstr(url, "://");
 600         if (host) {
 601                 *host = '\0';
 602                 protocol = get_protocol(url);
 603                 host += 3;
 604         } else {
 605                 host = url;
 606                 if (!url_is_local_not_ssh(url)) {
 607                         protocol = PROTO_SSH;
 608                         separator = ':';
 609                 }
 610         }
 611
 612         /*
 613          * Don't do destructive transforms as protocol code does
 614          * '[]' unwrapping in get_host_and_port()
 615          */
 616         end = host_end(&host, 0);
 617
 618         if (protocol == PROTO_LOCAL)
 619                 path = end;
 620         else if (protocol == PROTO_FILE && has_dos_drive_prefix(end))
 621                 path = end; /* "file://$(pwd)" may be "file://C:/projects/repo" */
 622         else
 623                 path = strchr(end, separator);
 624
 625         if (!path || !*path)
 626                 die("No path specified. See 'man git-pull' for valid url syntax");
 627
 628         /*
 629          * null-terminate hostname and point path to ~ for URL's like this:
 630          *    ssh://host.xz/~user/repo
 631          */
 632
 633         end = path; /* Need to \0 terminate host here */
 634         if (separator == ':')
 635                 path++; /* path starts after ':' */
 636         if (protocol == PROTO_GIT || protocol == PROTO_SSH) {
 637                 if (path[1] == '~')
 638                         path++;
 639         }
 640
 641         path = xstrdup(path);
 642         *end = '\0';
 643
 644         *ret_host = xstrdup(host);
 645         *ret_path = path;
 646         free(url);
 647         return protocol;
 648 }
 649
 650 static struct child_process no_fork = CHILD_PROCESS_INIT;
 651
 652 /*
 653  * This returns a dummy child_process if the transport protocol does not
 654  * need fork(2), or a struct child_process object if it does.  Once done,
 655  * finish the connection with finish_connect() with the value returned from
 656  * this function (it is safe to call finish_connect() with NULL to support
 657  * the former case).
 658  *
 659  * If it returns, the connect is successful; it just dies on errors (this
 660  * will hopefully be changed in a libification effort, to return NULL when
 661  * the connection failed).
 662  */
 663 struct child_process *git_connect(int fd[2], const char *url,
 664                                   const char *prog, int flags)
 665 {
 666         char *hostandport, *path;
 667         struct child_process *conn = &no_fork;
 668         enum protocol protocol;
 669         struct strbuf cmd = STRBUF_INIT;
 670
 671         /* Without this we cannot rely on waitpid() to tell
 672          * what happened to our children.
 673          */
 674         signal(SIGCHLD, SIG_DFL);
 675
 676         protocol = parse_connect_url(url, &hostandport, &path);
 677         if ((flags & CONNECT_DIAG_URL) && (protocol != PROTO_SSH)) {
 678                 printf("Diag: url=%s\n", url ? url : "NULL");
 679                 printf("Diag: protocol=%s\n", prot_name(protocol));
 680                 printf("Diag: hostandport=%s\n", hostandport ? hostandport : "NULL");
 681                 printf("Diag: path=%s\n", path ? path : "NULL");
 682                 conn = NULL;
 683         } else if (protocol == PROTO_GIT) {
 684                 /*
 685                  * Set up virtual host information based on where we will
 686                  * connect, unless the user has overridden us in
 687                  * the environment.
 688                  */
 689                 char *target_host = getenv("GIT_OVERRIDE_VIRTUAL_HOST");
 690                 if (target_host)
 691                         target_host = xstrdup(target_host);
 692                 else
 693                         target_host = xstrdup(hostandport);
 694
 695                 /* These underlying connection commands die() if they
 696                  * cannot connect.
 697                  */
 698                 if (git_use_proxy(hostandport))
 699                         conn = git_proxy_connect(fd, hostandport);
 700                 else
 701                         git_tcp_connect(fd, hostandport, flags);
 702                 /*
 703                  * Separate original protocol components prog and path
 704                  * from extended host header with a NUL byte.
 705                  *
 706                  * Note: Do not add any other headers here!  Doing so
 707                  * will cause older git-daemon servers to crash.
 708                  */
 709                 packet_write(fd[1],
 710                              "%s %s%chost=%s%c",
 711                              prog, path, 0,
 712                              target_host, 0);
 713                 free(target_host);
 714         } else {
 715                 conn = xmalloc(sizeof(*conn));
 716                 child_process_init(conn);
 717
 718                 strbuf_addstr(&cmd, prog);
 719                 strbuf_addch(&cmd, ' ');
 720                 sq_quote_buf(&cmd, path);
 721
 722                 conn->in = conn->out = -1;
 723                 if (protocol == PROTO_SSH) {
 724                         const char *ssh;
 725                         int putty;
 726                         char *ssh_host = hostandport;
 727                         const char *port = NULL;
 728                         get_host_and_port(&ssh_host, &port);
 729
 730                         if (!port)
 731                                 port = get_port(ssh_host);
 732
 733                         if (flags & CONNECT_DIAG_URL) {
 734                                 printf("Diag: url=%s\n", url ? url : "NULL");
 735                                 printf("Diag: protocol=%s\n", prot_name(protocol));
 736                                 printf("Diag: userandhost=%s\n", ssh_host ? ssh_host : "NULL");
 737                                 printf("Diag: port=%s\n", port ? port : "NONE");
 738                                 printf("Diag: path=%s\n", path ? path : "NULL");
 739
 740                                 free(hostandport);
 741                                 free(path);
 742                                 free(conn);
 743                                 return NULL;
 744                         } else {
 745                                 ssh = getenv("GIT_SSH_COMMAND");
 746                                 if (ssh) {
 747                                         conn->use_shell = 1;
 748                                         putty = 0;
 749                                 } else {
 750                                         ssh = getenv("GIT_SSH");
 751                                         if (!ssh)
 752                                                 ssh = "ssh";
 753                                         putty = !!strcasestr(ssh, "plink");
 754                                 }
 755
 756                                 argv_array_push(&conn->args, ssh);
 757                                 if (putty && !strcasestr(ssh, "tortoiseplink"))
 758                                         argv_array_push(&conn->args, "-batch");
 759                                 if (port) {
 760                                         /* P is for PuTTY, p is for OpenSSH */
 761                                         argv_array_push(&conn->args, putty ? "-P" : "-p");
 762                                         argv_array_push(&conn->args, port);
 763                                 }
 764                                 argv_array_push(&conn->args, ssh_host);
 765                         }
 766                 } else {
 767                         /* remove repo-local variables from the environment */
 768                         conn->env = local_repo_env;
 769                         conn->use_shell = 1;
 770                 }
 771                 argv_array_push(&conn->args, cmd.buf);
 772
 773                 if (start_command(conn))
 774                         die("unable to fork");
 775
 776                 fd[0] = conn->out; /* read from child's stdout */
 777                 fd[1] = conn->in;  /* write to child's stdin */
 778                 strbuf_release(&cmd);
 779         }
 780         free(hostandport);
 781         free(path);
 782         return conn;
 783 }
 784
 785 int git_connection_is_socket(struct child_process *conn)
 786 {
 787         return conn == &no_fork;
 788 }
 789
 790 int finish_connect(struct child_process *conn)
 791 {
 792         int code;
 793         if (!conn || git_connection_is_socket(conn))
 794                 return 0;
 795
 796         code = finish_command(conn);
 797         free(conn);
 798         return code;
 799 }