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 #include "transport.h"
  13
  14 static char *server_capabilities;
  15 static const char *parse_feature_value(const char *, const char *, int *);
  16
  17 static int check_ref(const char *name, unsigned int flags)
  18 {
  19         if (!flags)
  20                 return 1;
  21
  22         if (!skip_prefix(name, "refs/", &name))
  23                 return 0;
  24
  25         /* REF_NORMAL means that we don't want the magic fake tag refs */
  26         if ((flags & REF_NORMAL) && check_refname_format(name, 0))
  27                 return 0;
  28
  29         /* REF_HEADS means that we want regular branch heads */
  30         if ((flags & REF_HEADS) && starts_with(name, "heads/"))
  31                 return 1;
  32
  33         /* REF_TAGS means that we want tags */
  34         if ((flags & REF_TAGS) && starts_with(name, "tags/"))
  35                 return 1;
  36
  37         /* All type bits clear means that we are ok with anything */
  38         return !(flags & ~REF_NORMAL);
  39 }
  40
  41 int check_ref_type(const struct ref *ref, int flags)
  42 {
  43         return check_ref(ref->name, flags);
  44 }
  45
  46 static void die_initial_contact(int got_at_least_one_head)
  47 {
  48         if (got_at_least_one_head)
  49                 die("The remote end hung up upon initial contact");
  50         else
  51                 die("Could not read from remote repository.\n\n"
  52                     "Please make sure you have the correct access rights\n"
  53                     "and the repository exists.");
  54 }
  55
  56 static void parse_one_symref_info(struct string_list *symref, const char *val, int len)
  57 {
  58         char *sym, *target;
  59         struct string_list_item *item;
  60
  61         if (!len)
  62                 return; /* just "symref" */
  63         /* e.g. "symref=HEAD:refs/heads/master" */
  64         sym = xmemdupz(val, len);
  65         target = strchr(sym, ':');
  66         if (!target)
  67                 /* just "symref=something" */
  68                 goto reject;
  69         *(target++) = '\0';
  70         if (check_refname_format(sym, REFNAME_ALLOW_ONELEVEL) ||
  71             check_refname_format(target, REFNAME_ALLOW_ONELEVEL))
  72                 /* "symref=bogus:pair */
  73                 goto reject;
  74         item = string_list_append(symref, sym);
  75         item->util = target;
  76         return;
  77 reject:
  78         free(sym);
  79         return;
  80 }
  81
  82 static void annotate_refs_with_symref_info(struct ref *ref)
  83 {
  84         struct string_list symref = STRING_LIST_INIT_DUP;
  85         const char *feature_list = server_capabilities;
  86
  87         while (feature_list) {
  88                 int len;
  89                 const char *val;
  90
  91                 val = parse_feature_value(feature_list, "symref", &len);
  92                 if (!val)
  93                         break;
  94                 parse_one_symref_info(&symref, val, len);
  95                 feature_list = val + 1;
  96         }
  97         string_list_sort(&symref);
  98
  99         for (; ref; ref = ref->next) {
 100                 struct string_list_item *item;
 101                 item = string_list_lookup(&symref, ref->name);
 102                 if (!item)
 103                         continue;
 104                 ref->symref = xstrdup((char *)item->util);
 105         }
 106         string_list_clear(&symref, 0);
 107 }
 108
 109 /*
 110  * Read all the refs from the other end
 111  */
 112 struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
 113                               struct ref **list, unsigned int flags,
 114                               struct sha1_array *extra_have,
 115                               struct sha1_array *shallow_points)
 116 {
 117         struct ref **orig_list = list;
 118         int got_at_least_one_head = 0;
 119
 120         *list = NULL;
 121         for (;;) {
 122                 struct ref *ref;
 123                 unsigned char old_sha1[20];
 124                 char *name;
 125                 int len, name_len;
 126                 char *buffer = packet_buffer;
 127                 const char *arg;
 128
 129                 len = packet_read(in, &src_buf, &src_len,
 130                                   packet_buffer, sizeof(packet_buffer),
 131                                   PACKET_READ_GENTLE_ON_EOF |
 132                                   PACKET_READ_CHOMP_NEWLINE);
 133                 if (len < 0)
 134                         die_initial_contact(got_at_least_one_head);
 135
 136                 if (!len)
 137                         break;
 138
 139                 if (len > 4 && skip_prefix(buffer, "ERR ", &arg))
 140                         die("remote error: %s", arg);
 141
 142                 if (len == 48 && skip_prefix(buffer, "shallow ", &arg)) {
 143                         if (get_sha1_hex(arg, old_sha1))
 144                                 die("protocol error: expected shallow sha-1, got '%s'", arg);
 145                         if (!shallow_points)
 146                                 die("repository on the other end cannot be shallow");
 147                         sha1_array_append(shallow_points, old_sha1);
 148                         continue;
 149                 }
 150
 151                 if (len < 42 || get_sha1_hex(buffer, old_sha1) || buffer[40] != ' ')
 152                         die("protocol error: expected sha/ref, got '%s'", buffer);
 153                 name = buffer + 41;
 154
 155                 name_len = strlen(name);
 156                 if (len != name_len + 41) {
 157                         free(server_capabilities);
 158                         server_capabilities = xstrdup(name + name_len + 1);
 159                 }
 160
 161                 if (extra_have && !strcmp(name, ".have")) {
 162                         sha1_array_append(extra_have, old_sha1);
 163                         continue;
 164                 }
 165
 166                 if (!check_ref(name, flags))
 167                         continue;
 168                 ref = alloc_ref(buffer + 41);
 169                 hashcpy(ref->old_sha1, old_sha1);
 170                 *list = ref;
 171                 list = &ref->next;
 172                 got_at_least_one_head = 1;
 173         }
 174
 175         annotate_refs_with_symref_info(*orig_list);
 176
 177         return list;
 178 }
 179
 180 static const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
 181 {
 182         int len;
 183
 184         if (!feature_list)
 185                 return NULL;
 186
 187         len = strlen(feature);
 188         while (*feature_list) {
 189                 const char *found = strstr(feature_list, feature);
 190                 if (!found)
 191                         return NULL;
 192                 if (feature_list == found || isspace(found[-1])) {
 193                         const char *value = found + len;
 194                         /* feature with no value (e.g., "thin-pack") */
 195                         if (!*value || isspace(*value)) {
 196                                 if (lenp)
 197                                         *lenp = 0;
 198                                 return value;
 199                         }
 200                         /* feature with a value (e.g., "agent=git/1.2.3") */
 201                         else if (*value == '=') {
 202                                 value++;
 203                                 if (lenp)
 204                                         *lenp = strcspn(value, " \t\n");
 205                                 return value;
 206                         }
 207                         /*
 208                          * otherwise we matched a substring of another feature;
 209                          * keep looking
 210                          */
 211                 }
 212                 feature_list = found + 1;
 213         }
 214         return NULL;
 215 }
 216
 217 int parse_feature_request(const char *feature_list, const char *feature)
 218 {
 219         return !!parse_feature_value(feature_list, feature, NULL);
 220 }
 221
 222 const char *server_feature_value(const char *feature, int *len)
 223 {
 224         return parse_feature_value(server_capabilities, feature, len);
 225 }
 226
 227 int server_supports(const char *feature)
 228 {
 229         return !!server_feature_value(feature, NULL);
 230 }
 231
 232 enum protocol {
 233         PROTO_LOCAL = 1,
 234         PROTO_FILE,
 235         PROTO_SSH,
 236         PROTO_GIT
 237 };
 238
 239 int url_is_local_not_ssh(const char *url)
 240 {
 241         const char *colon = strchr(url, ':');
 242         const char *slash = strchr(url, '/');
 243         return !colon || (slash && slash < colon) ||
 244                 has_dos_drive_prefix(url);
 245 }
 246
 247 static const char *prot_name(enum protocol protocol)
 248 {
 249         switch (protocol) {
 250                 case PROTO_LOCAL:
 251                 case PROTO_FILE:
 252                         return "file";
 253                 case PROTO_SSH:
 254                         return "ssh";
 255                 case PROTO_GIT:
 256                         return "git";
 257                 default:
 258                         return "unknown protocol";
 259         }
 260 }
 261
 262 static enum protocol get_protocol(const char *name)
 263 {
 264         if (!strcmp(name, "ssh"))
 265                 return PROTO_SSH;
 266         if (!strcmp(name, "git"))
 267                 return PROTO_GIT;
 268         if (!strcmp(name, "git+ssh"))
 269                 return PROTO_SSH;
 270         if (!strcmp(name, "ssh+git"))
 271                 return PROTO_SSH;
 272         if (!strcmp(name, "file"))
 273                 return PROTO_FILE;
 274         die("I don't handle protocol '%s'", name);
 275 }
 276
 277 static char *host_end(char **hoststart, int removebrackets)
 278 {
 279         char *host = *hoststart;
 280         char *end;
 281         char *start = strstr(host, "@[");
 282         if (start)
 283                 start++; /* Jump over '@' */
 284         else
 285                 start = host;
 286         if (start[0] == '[') {
 287                 end = strchr(start + 1, ']');
 288                 if (end) {
 289                         if (removebrackets) {
 290                                 *end = 0;
 291                                 memmove(start, start + 1, end - start);
 292                                 end++;
 293                         }
 294                 } else
 295                         end = host;
 296         } else
 297                 end = host;
 298         return end;
 299 }
 300
 301 #define STR_(s) # s
 302 #define STR(s)  STR_(s)
 303
 304 static void get_host_and_port(char **host, const char **port)
 305 {
 306         char *colon, *end;
 307         end = host_end(host, 1);
 308         colon = strchr(end, ':');
 309         if (colon) {
 310                 long portnr = strtol(colon + 1, &end, 10);
 311                 if (end != colon + 1 && *end == '\0' && 0 <= portnr && portnr < 65536) {
 312                         *colon = 0;
 313                         *port = colon + 1;
 314                 } else if (!colon[1]) {
 315                         *colon = 0;
 316                 }
 317         }
 318 }
 319
 320 static void enable_keepalive(int sockfd)
 321 {
 322         int ka = 1;
 323
 324         if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
 325                 fprintf(stderr, "unable to set SO_KEEPALIVE on socket: %s\n",
 326                         strerror(errno));
 327 }
 328
 329 #ifndef NO_IPV6
 330
 331 static const char *ai_name(const struct addrinfo *ai)
 332 {
 333         static char addr[NI_MAXHOST];
 334         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
 335                         NI_NUMERICHOST) != 0)
 336                 xsnprintf(addr, sizeof(addr), "(unknown)");
 337
 338         return addr;
 339 }
 340
 341 /*
 342  * Returns a connected socket() fd, or else die()s.
 343  */
 344 static int git_tcp_connect_sock(char *host, int flags)
 345 {
 346         struct strbuf error_message = STRBUF_INIT;
 347         int sockfd = -1;
 348         const char *port = STR(DEFAULT_GIT_PORT);
 349         struct addrinfo hints, *ai0, *ai;
 350         int gai;
 351         int cnt = 0;
 352
 353         get_host_and_port(&host, &port);
 354         if (!*port)
 355                 port = "<none>";
 356
 357         memset(&hints, 0, sizeof(hints));
 358         hints.ai_socktype = SOCK_STREAM;
 359         hints.ai_protocol = IPPROTO_TCP;
 360
 361         if (flags & CONNECT_VERBOSE)
 362                 fprintf(stderr, "Looking up %s ... ", host);
 363
 364         gai = getaddrinfo(host, port, &hints, &ai);
 365         if (gai)
 366                 die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
 367
 368         if (flags & CONNECT_VERBOSE)
 369                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 370
 371         for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
 372                 sockfd = socket(ai->ai_family,
 373                                 ai->ai_socktype, ai->ai_protocol);
 374                 if ((sockfd < 0) ||
 375                     (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
 376                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 377                                     host, cnt, ai_name(ai), strerror(errno));
 378                         if (0 <= sockfd)
 379                                 close(sockfd);
 380                         sockfd = -1;
 381                         continue;
 382                 }
 383                 if (flags & CONNECT_VERBOSE)
 384                         fprintf(stderr, "%s ", ai_name(ai));
 385                 break;
 386         }
 387
 388         freeaddrinfo(ai0);
 389
 390         if (sockfd < 0)
 391                 die("unable to connect to %s:\n%s", host, error_message.buf);
 392
 393         enable_keepalive(sockfd);
 394
 395         if (flags & CONNECT_VERBOSE)
 396                 fprintf(stderr, "done.\n");
 397
 398         strbuf_release(&error_message);
 399
 400         return sockfd;
 401 }
 402
 403 #else /* NO_IPV6 */
 404
 405 /*
 406  * Returns a connected socket() fd, or else die()s.
 407  */
 408 static int git_tcp_connect_sock(char *host, int flags)
 409 {
 410         struct strbuf error_message = STRBUF_INIT;
 411         int sockfd = -1;
 412         const char *port = STR(DEFAULT_GIT_PORT);
 413         char *ep;
 414         struct hostent *he;
 415         struct sockaddr_in sa;
 416         char **ap;
 417         unsigned int nport;
 418         int cnt;
 419
 420         get_host_and_port(&host, &port);
 421
 422         if (flags & CONNECT_VERBOSE)
 423                 fprintf(stderr, "Looking up %s ... ", host);
 424
 425         he = gethostbyname(host);
 426         if (!he)
 427                 die("Unable to look up %s (%s)", host, hstrerror(h_errno));
 428         nport = strtoul(port, &ep, 10);
 429         if ( ep == port || *ep ) {
 430                 /* Not numeric */
 431                 struct servent *se = getservbyname(port,"tcp");
 432                 if ( !se )
 433                         die("Unknown port %s", port);
 434                 nport = se->s_port;
 435         }
 436
 437         if (flags & CONNECT_VERBOSE)
 438                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 439
 440         for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
 441                 memset(&sa, 0, sizeof sa);
 442                 sa.sin_family = he->h_addrtype;
 443                 sa.sin_port = htons(nport);
 444                 memcpy(&sa.sin_addr, *ap, he->h_length);
 445
 446                 sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 447                 if ((sockfd < 0) ||
 448                     connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 449                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 450                                 host,
 451                                 cnt,
 452                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr),
 453                                 strerror(errno));
 454                         if (0 <= sockfd)
 455                                 close(sockfd);
 456                         sockfd = -1;
 457                         continue;
 458                 }
 459                 if (flags & CONNECT_VERBOSE)
 460                         fprintf(stderr, "%s ",
 461                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr));
 462                 break;
 463         }
 464
 465         if (sockfd < 0)
 466                 die("unable to connect to %s:\n%s", host, error_message.buf);
 467
 468         enable_keepalive(sockfd);
 469
 470         if (flags & CONNECT_VERBOSE)
 471                 fprintf(stderr, "done.\n");
 472
 473         return sockfd;
 474 }
 475
 476 #endif /* NO_IPV6 */
 477
 478
 479 static void git_tcp_connect(int fd[2], char *host, int flags)
 480 {
 481         int sockfd = git_tcp_connect_sock(host, flags);
 482
 483         fd[0] = sockfd;
 484         fd[1] = dup(sockfd);
 485 }
 486
 487
 488 static char *git_proxy_command;
 489
 490 static int git_proxy_command_options(const char *var, const char *value,
 491                 void *cb)
 492 {
 493         if (!strcmp(var, "core.gitproxy")) {
 494                 const char *for_pos;
 495                 int matchlen = -1;
 496                 int hostlen;
 497                 const char *rhost_name = cb;
 498                 int rhost_len = strlen(rhost_name);
 499
 500                 if (git_proxy_command)
 501                         return 0;
 502                 if (!value)
 503                         return config_error_nonbool(var);
 504                 /* [core]
 505                  * ;# matches www.kernel.org as well
 506                  * gitproxy = netcatter-1 for kernel.org
 507                  * gitproxy = netcatter-2 for sample.xz
 508                  * gitproxy = netcatter-default
 509                  */
 510                 for_pos = strstr(value, " for ");
 511                 if (!for_pos)
 512                         /* matches everybody */
 513                         matchlen = strlen(value);
 514                 else {
 515                         hostlen = strlen(for_pos + 5);
 516                         if (rhost_len < hostlen)
 517                                 matchlen = -1;
 518                         else if (!strncmp(for_pos + 5,
 519                                           rhost_name + rhost_len - hostlen,
 520                                           hostlen) &&
 521                                  ((rhost_len == hostlen) ||
 522                                   rhost_name[rhost_len - hostlen -1] == '.'))
 523                                 matchlen = for_pos - value;
 524                         else
 525                                 matchlen = -1;
 526                 }
 527                 if (0 <= matchlen) {
 528                         /* core.gitproxy = none for kernel.org */
 529                         if (matchlen == 4 &&
 530                             !memcmp(value, "none", 4))
 531                                 matchlen = 0;
 532                         git_proxy_command = xmemdupz(value, matchlen);
 533                 }
 534                 return 0;
 535         }
 536
 537         return git_default_config(var, value, cb);
 538 }
 539
 540 static int git_use_proxy(const char *host)
 541 {
 542         git_proxy_command = getenv("GIT_PROXY_COMMAND");
 543         git_config(git_proxy_command_options, (void*)host);
 544         return (git_proxy_command && *git_proxy_command);
 545 }
 546
 547 static struct child_process *git_proxy_connect(int fd[2], char *host)
 548 {
 549         const char *port = STR(DEFAULT_GIT_PORT);
 550         struct child_process *proxy;
 551
 552         get_host_and_port(&host, &port);
 553
 554         proxy = xmalloc(sizeof(*proxy));
 555         child_process_init(proxy);
 556         argv_array_push(&proxy->args, git_proxy_command);
 557         argv_array_push(&proxy->args, host);
 558         argv_array_push(&proxy->args, port);
 559         proxy->in = -1;
 560         proxy->out = -1;
 561         if (start_command(proxy))
 562                 die("cannot start proxy %s", git_proxy_command);
 563         fd[0] = proxy->out; /* read from proxy stdout */
 564         fd[1] = proxy->in;  /* write to proxy stdin */
 565         return proxy;
 566 }
 567
 568 static char *get_port(char *host)
 569 {
 570         char *end;
 571         char *p = strchr(host, ':');
 572
 573         if (p) {
 574                 long port = strtol(p + 1, &end, 10);
 575                 if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
 576                         *p = '\0';
 577                         return p+1;
 578                 }
 579         }
 580
 581         return NULL;
 582 }
 583
 584 /*
 585  * Extract protocol and relevant parts from the specified connection URL.
 586  * The caller must free() the returned strings.
 587  */
 588 static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
 589                                        char **ret_path)
 590 {
 591         char *url;
 592         char *host, *path;
 593         char *end;
 594         int separator = '/';
 595         enum protocol protocol = PROTO_LOCAL;
 596
 597         if (is_url(url_orig))
 598                 url = url_decode(url_orig);
 599         else
 600                 url = xstrdup(url_orig);
 601
 602         host = strstr(url, "://");
 603         if (host) {
 604                 *host = '\0';
 605                 protocol = get_protocol(url);
 606                 host += 3;
 607         } else {
 608                 host = url;
 609                 if (!url_is_local_not_ssh(url)) {
 610                         protocol = PROTO_SSH;
 611                         separator = ':';
 612                 }
 613         }
 614
 615         /*
 616          * Don't do destructive transforms as protocol code does
 617          * '[]' unwrapping in get_host_and_port()
 618          */
 619         end = host_end(&host, 0);
 620
 621         if (protocol == PROTO_LOCAL)
 622                 path = end;
 623         else if (protocol == PROTO_FILE && has_dos_drive_prefix(end))
 624                 path = end; /* "file://$(pwd)" may be "file://C:/projects/repo" */
 625         else
 626                 path = strchr(end, separator);
 627
 628         if (!path || !*path)
 629                 die("No path specified. See 'man git-pull' for valid url syntax");
 630
 631         /*
 632          * null-terminate hostname and point path to ~ for URL's like this:
 633          *    ssh://host.xz/~user/repo
 634          */
 635
 636         end = path; /* Need to \0 terminate host here */
 637         if (separator == ':')
 638                 path++; /* path starts after ':' */
 639         if (protocol == PROTO_GIT || protocol == PROTO_SSH) {
 640                 if (path[1] == '~')
 641                         path++;
 642         }
 643
 644         path = xstrdup(path);
 645         *end = '\0';
 646
 647         *ret_host = xstrdup(host);
 648         *ret_path = path;
 649         free(url);
 650         return protocol;
 651 }
 652
 653 static struct child_process no_fork = CHILD_PROCESS_INIT;
 654
 655 /*
 656  * This returns a dummy child_process if the transport protocol does not
 657  * need fork(2), or a struct child_process object if it does.  Once done,
 658  * finish the connection with finish_connect() with the value returned from
 659  * this function (it is safe to call finish_connect() with NULL to support
 660  * the former case).
 661  *
 662  * If it returns, the connect is successful; it just dies on errors (this
 663  * will hopefully be changed in a libification effort, to return NULL when
 664  * the connection failed).
 665  */
 666 struct child_process *git_connect(int fd[2], const char *url,
 667                                   const char *prog, int flags)
 668 {
 669         char *hostandport, *path;
 670         struct child_process *conn = &no_fork;
 671         enum protocol protocol;
 672         struct strbuf cmd = STRBUF_INIT;
 673
 674         /* Without this we cannot rely on waitpid() to tell
 675          * what happened to our children.
 676          */
 677         signal(SIGCHLD, SIG_DFL);
 678
 679         protocol = parse_connect_url(url, &hostandport, &path);
 680         if ((flags & CONNECT_DIAG_URL) && (protocol != PROTO_SSH)) {
 681                 printf("Diag: url=%s\n", url ? url : "NULL");
 682                 printf("Diag: protocol=%s\n", prot_name(protocol));
 683                 printf("Diag: hostandport=%s\n", hostandport ? hostandport : "NULL");
 684                 printf("Diag: path=%s\n", path ? path : "NULL");
 685                 conn = NULL;
 686         } else if (protocol == PROTO_GIT) {
 687                 /*
 688                  * Set up virtual host information based on where we will
 689                  * connect, unless the user has overridden us in
 690                  * the environment.
 691                  */
 692                 char *target_host = getenv("GIT_OVERRIDE_VIRTUAL_HOST");
 693                 if (target_host)
 694                         target_host = xstrdup(target_host);
 695                 else
 696                         target_host = xstrdup(hostandport);
 697
 698                 transport_check_allowed("git");
 699
 700                 /* These underlying connection commands die() if they
 701                  * cannot connect.
 702                  */
 703                 if (git_use_proxy(hostandport))
 704                         conn = git_proxy_connect(fd, hostandport);
 705                 else
 706                         git_tcp_connect(fd, hostandport, flags);
 707                 /*
 708                  * Separate original protocol components prog and path
 709                  * from extended host header with a NUL byte.
 710                  *
 711                  * Note: Do not add any other headers here!  Doing so
 712                  * will cause older git-daemon servers to crash.
 713                  */
 714                 packet_write(fd[1],
 715                              "%s %s%chost=%s%c",
 716                              prog, path, 0,
 717                              target_host, 0);
 718                 free(target_host);
 719         } else {
 720                 conn = xmalloc(sizeof(*conn));
 721                 child_process_init(conn);
 722
 723                 strbuf_addstr(&cmd, prog);
 724                 strbuf_addch(&cmd, ' ');
 725                 sq_quote_buf(&cmd, path);
 726
 727                 /* remove repo-local variables from the environment */
 728                 conn->env = local_repo_env;
 729                 conn->use_shell = 1;
 730                 conn->in = conn->out = -1;
 731                 if (protocol == PROTO_SSH) {
 732                         const char *ssh;
 733                         int putty = 0, tortoiseplink = 0;
 734                         char *ssh_host = hostandport;
 735                         const char *port = NULL;
 736                         transport_check_allowed("ssh");
 737                         get_host_and_port(&ssh_host, &port);
 738
 739                         if (!port)
 740                                 port = get_port(ssh_host);
 741
 742                         if (flags & CONNECT_DIAG_URL) {
 743                                 printf("Diag: url=%s\n", url ? url : "NULL");
 744                                 printf("Diag: protocol=%s\n", prot_name(protocol));
 745                                 printf("Diag: userandhost=%s\n", ssh_host ? ssh_host : "NULL");
 746                                 printf("Diag: port=%s\n", port ? port : "NONE");
 747                                 printf("Diag: path=%s\n", path ? path : "NULL");
 748
 749                                 free(hostandport);
 750                                 free(path);
 751                                 free(conn);
 752                                 return NULL;
 753                         }
 754
 755                         ssh = getenv("GIT_SSH_COMMAND");
 756                         if (!ssh) {
 757                                 const char *base;
 758                                 char *ssh_dup;
 759
 760                                 /*
 761                                  * GIT_SSH is the no-shell version of
 762                                  * GIT_SSH_COMMAND (and must remain so for
 763                                  * historical compatibility).
 764                                  */
 765                                 conn->use_shell = 0;
 766
 767                                 ssh = getenv("GIT_SSH");
 768                                 if (!ssh)
 769                                         ssh = "ssh";
 770
 771                                 ssh_dup = xstrdup(ssh);
 772                                 base = basename(ssh_dup);
 773
 774                                 tortoiseplink = !strcasecmp(base, "tortoiseplink") ||
 775                                         !strcasecmp(base, "tortoiseplink.exe");
 776                                 putty = tortoiseplink ||
 777                                         !strcasecmp(base, "plink") ||
 778                                         !strcasecmp(base, "plink.exe");
 779
 780                                 free(ssh_dup);
 781                         }
 782
 783                         argv_array_push(&conn->args, ssh);
 784                         if (tortoiseplink)
 785                                 argv_array_push(&conn->args, "-batch");
 786                         if (port) {
 787                                 /* P is for PuTTY, p is for OpenSSH */
 788                                 argv_array_push(&conn->args, putty ? "-P" : "-p");
 789                                 argv_array_push(&conn->args, port);
 790                         }
 791                         argv_array_push(&conn->args, ssh_host);
 792                 } else {
 793                         transport_check_allowed("file");
 794                 }
 795                 argv_array_push(&conn->args, cmd.buf);
 796
 797                 if (start_command(conn))
 798                         die("unable to fork");
 799
 800                 fd[0] = conn->out; /* read from child's stdout */
 801                 fd[1] = conn->in;  /* write to child's stdin */
 802                 strbuf_release(&cmd);
 803         }
 804         free(hostandport);
 805         free(path);
 806         return conn;
 807 }
 808
 809 int git_connection_is_socket(struct child_process *conn)
 810 {
 811         return conn == &no_fork;
 812 }
 813
 814 int finish_connect(struct child_process *conn)
 815 {
 816         int code;
 817         if (!conn || git_connection_is_socket(conn))
 818                 return 0;
 819
 820         code = finish_command(conn);
 821         free(conn);
 822         return code;
 823 }