git.oblomov.eu Git - git/blob - connect.c

   1 #include "git-compat-util.h"
   2 #include "cache.h"
   3 #include "config.h"
   4 #include "pkt-line.h"
   5 #include "quote.h"
   6 #include "refs.h"
   7 #include "run-command.h"
   8 #include "remote.h"
   9 #include "connect.h"
  10 #include "url.h"
  11 #include "string-list.h"
  12 #include "sha1-array.h"
  13 #include "transport.h"
  14 #include "strbuf.h"
  15 #include "protocol.h"
  16 #include "alias.h"
  17
  18 static char *server_capabilities;
  19 static const char *parse_feature_value(const char *, const char *, int *);
  20
  21 static int check_ref(const char *name, unsigned int flags)
  22 {
  23         if (!flags)
  24                 return 1;
  25
  26         if (!skip_prefix(name, "refs/", &name))
  27                 return 0;
  28
  29         /* REF_NORMAL means that we don't want the magic fake tag refs */
  30         if ((flags & REF_NORMAL) && check_refname_format(name, 0))
  31                 return 0;
  32
  33         /* REF_HEADS means that we want regular branch heads */
  34         if ((flags & REF_HEADS) && starts_with(name, "heads/"))
  35                 return 1;
  36
  37         /* REF_TAGS means that we want tags */
  38         if ((flags & REF_TAGS) && starts_with(name, "tags/"))
  39                 return 1;
  40
  41         /* All type bits clear means that we are ok with anything */
  42         return !(flags & ~REF_NORMAL);
  43 }
  44
  45 int check_ref_type(const struct ref *ref, int flags)
  46 {
  47         return check_ref(ref->name, flags);
  48 }
  49
  50 static void die_initial_contact(int unexpected)
  51 {
  52         if (unexpected)
  53                 die(_("The remote end hung up upon initial contact"));
  54         else
  55                 die(_("Could not read from remote repository.\n\n"
  56                       "Please make sure you have the correct access rights\n"
  57                       "and the repository exists."));
  58 }
  59
  60 static void parse_one_symref_info(struct string_list *symref, const char *val, int len)
  61 {
  62         char *sym, *target;
  63         struct string_list_item *item;
  64
  65         if (!len)
  66                 return; /* just "symref" */
  67         /* e.g. "symref=HEAD:refs/heads/master" */
  68         sym = xmemdupz(val, len);
  69         target = strchr(sym, ':');
  70         if (!target)
  71                 /* just "symref=something" */
  72                 goto reject;
  73         *(target++) = '\0';
  74         if (check_refname_format(sym, REFNAME_ALLOW_ONELEVEL) ||
  75             check_refname_format(target, REFNAME_ALLOW_ONELEVEL))
  76                 /* "symref=bogus:pair */
  77                 goto reject;
  78         item = string_list_append_nodup(symref, sym);
  79         item->util = target;
  80         return;
  81 reject:
  82         free(sym);
  83         return;
  84 }
  85
  86 static void annotate_refs_with_symref_info(struct ref *ref)
  87 {
  88         struct string_list symref = STRING_LIST_INIT_DUP;
  89         const char *feature_list = server_capabilities;
  90
  91         while (feature_list) {
  92                 int len;
  93                 const char *val;
  94
  95                 val = parse_feature_value(feature_list, "symref", &len);
  96                 if (!val)
  97                         break;
  98                 parse_one_symref_info(&symref, val, len);
  99                 feature_list = val + 1;
 100         }
 101         string_list_sort(&symref);
 102
 103         for (; ref; ref = ref->next) {
 104                 struct string_list_item *item;
 105                 item = string_list_lookup(&symref, ref->name);
 106                 if (!item)
 107                         continue;
 108                 ref->symref = xstrdup((char *)item->util);
 109         }
 110         string_list_clear(&symref, 0);
 111 }
 112
 113 /*
 114  * Read one line of a server's ref advertisement into packet_buffer.
 115  */
 116 static int read_remote_ref(int in, char **src_buf, size_t *src_len,
 117                            int *responded)
 118 {
 119         int len = packet_read(in, src_buf, src_len,
 120                               packet_buffer, sizeof(packet_buffer),
 121                               PACKET_READ_GENTLE_ON_EOF |
 122                               PACKET_READ_CHOMP_NEWLINE);
 123         const char *arg;
 124         if (len < 0)
 125                 die_initial_contact(*responded);
 126         if (len > 4 && skip_prefix(packet_buffer, "ERR ", &arg))
 127                 die("remote error: %s", arg);
 128
 129         *responded = 1;
 130
 131         return len;
 132 }
 133
 134 #define EXPECTING_PROTOCOL_VERSION 0
 135 #define EXPECTING_FIRST_REF 1
 136 #define EXPECTING_REF 2
 137 #define EXPECTING_SHALLOW 3
 138
 139 /* Returns 1 if packet_buffer is a protocol version pkt-line, 0 otherwise. */
 140 static int process_protocol_version(void)
 141 {
 142         switch (determine_protocol_version_client(packet_buffer)) {
 143         case protocol_v1:
 144                 return 1;
 145         case protocol_v0:
 146                 return 0;
 147         default:
 148                 die("server is speaking an unknown protocol");
 149         }
 150 }
 151
 152 static void process_capabilities(int *len)
 153 {
 154         int nul_location = strlen(packet_buffer);
 155         if (nul_location == *len)
 156                 return;
 157         server_capabilities = xstrdup(packet_buffer + nul_location + 1);
 158         *len = nul_location;
 159 }
 160
 161 static int process_dummy_ref(void)
 162 {
 163         struct object_id oid;
 164         const char *name;
 165
 166         if (parse_oid_hex(packet_buffer, &oid, &name))
 167                 return 0;
 168         if (*name != ' ')
 169                 return 0;
 170         name++;
 171
 172         return !oidcmp(&null_oid, &oid) && !strcmp(name, "capabilities^{}");
 173 }
 174
 175 static void check_no_capabilities(int len)
 176 {
 177         if (strlen(packet_buffer) != len)
 178                 warning("Ignoring capabilities after first line '%s'",
 179                         packet_buffer + strlen(packet_buffer));
 180 }
 181
 182 static int process_ref(int len, struct ref ***list, unsigned int flags,
 183                        struct oid_array *extra_have)
 184 {
 185         struct object_id old_oid;
 186         const char *name;
 187
 188         if (parse_oid_hex(packet_buffer, &old_oid, &name))
 189                 return 0;
 190         if (*name != ' ')
 191                 return 0;
 192         name++;
 193
 194         if (extra_have && !strcmp(name, ".have")) {
 195                 oid_array_append(extra_have, &old_oid);
 196         } else if (!strcmp(name, "capabilities^{}")) {
 197                 die("protocol error: unexpected capabilities^{}");
 198         } else if (check_ref(name, flags)) {
 199                 struct ref *ref = alloc_ref(name);
 200                 oidcpy(&ref->old_oid, &old_oid);
 201                 **list = ref;
 202                 *list = &ref->next;
 203         }
 204         check_no_capabilities(len);
 205         return 1;
 206 }
 207
 208 static int process_shallow(int len, struct oid_array *shallow_points)
 209 {
 210         const char *arg;
 211         struct object_id old_oid;
 212
 213         if (!skip_prefix(packet_buffer, "shallow ", &arg))
 214                 return 0;
 215
 216         if (get_oid_hex(arg, &old_oid))
 217                 die("protocol error: expected shallow sha-1, got '%s'", arg);
 218         if (!shallow_points)
 219                 die("repository on the other end cannot be shallow");
 220         oid_array_append(shallow_points, &old_oid);
 221         check_no_capabilities(len);
 222         return 1;
 223 }
 224
 225 /*
 226  * Read all the refs from the other end
 227  */
 228 struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
 229                               struct ref **list, unsigned int flags,
 230                               struct oid_array *extra_have,
 231                               struct oid_array *shallow_points)
 232 {
 233         struct ref **orig_list = list;
 234
 235         /*
 236          * A hang-up after seeing some response from the other end
 237          * means that it is unexpected, as we know the other end is
 238          * willing to talk to us.  A hang-up before seeing any
 239          * response does not necessarily mean an ACL problem, though.
 240          */
 241         int responded = 0;
 242         int len;
 243         int state = EXPECTING_PROTOCOL_VERSION;
 244
 245         *list = NULL;
 246
 247         while ((len = read_remote_ref(in, &src_buf, &src_len, &responded))) {
 248                 switch (state) {
 249                 case EXPECTING_PROTOCOL_VERSION:
 250                         if (process_protocol_version()) {
 251                                 state = EXPECTING_FIRST_REF;
 252                                 break;
 253                         }
 254                         state = EXPECTING_FIRST_REF;
 255                         /* fallthrough */
 256                 case EXPECTING_FIRST_REF:
 257                         process_capabilities(&len);
 258                         if (process_dummy_ref()) {
 259                                 state = EXPECTING_SHALLOW;
 260                                 break;
 261                         }
 262                         state = EXPECTING_REF;
 263                         /* fallthrough */
 264                 case EXPECTING_REF:
 265                         if (process_ref(len, &list, flags, extra_have))
 266                                 break;
 267                         state = EXPECTING_SHALLOW;
 268                         /* fallthrough */
 269                 case EXPECTING_SHALLOW:
 270                         if (process_shallow(len, shallow_points))
 271                                 break;
 272                         die("protocol error: unexpected '%s'", packet_buffer);
 273                 default:
 274                         die("unexpected state %d", state);
 275                 }
 276         }
 277
 278         annotate_refs_with_symref_info(*orig_list);
 279
 280         return list;
 281 }
 282
 283 static const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
 284 {
 285         int len;
 286
 287         if (!feature_list)
 288                 return NULL;
 289
 290         len = strlen(feature);
 291         while (*feature_list) {
 292                 const char *found = strstr(feature_list, feature);
 293                 if (!found)
 294                         return NULL;
 295                 if (feature_list == found || isspace(found[-1])) {
 296                         const char *value = found + len;
 297                         /* feature with no value (e.g., "thin-pack") */
 298                         if (!*value || isspace(*value)) {
 299                                 if (lenp)
 300                                         *lenp = 0;
 301                                 return value;
 302                         }
 303                         /* feature with a value (e.g., "agent=git/1.2.3") */
 304                         else if (*value == '=') {
 305                                 value++;
 306                                 if (lenp)
 307                                         *lenp = strcspn(value, " \t\n");
 308                                 return value;
 309                         }
 310                         /*
 311                          * otherwise we matched a substring of another feature;
 312                          * keep looking
 313                          */
 314                 }
 315                 feature_list = found + 1;
 316         }
 317         return NULL;
 318 }
 319
 320 int parse_feature_request(const char *feature_list, const char *feature)
 321 {
 322         return !!parse_feature_value(feature_list, feature, NULL);
 323 }
 324
 325 const char *server_feature_value(const char *feature, int *len)
 326 {
 327         return parse_feature_value(server_capabilities, feature, len);
 328 }
 329
 330 int server_supports(const char *feature)
 331 {
 332         return !!server_feature_value(feature, NULL);
 333 }
 334
 335 enum protocol {
 336         PROTO_LOCAL = 1,
 337         PROTO_FILE,
 338         PROTO_SSH,
 339         PROTO_GIT
 340 };
 341
 342 int url_is_local_not_ssh(const char *url)
 343 {
 344         const char *colon = strchr(url, ':');
 345         const char *slash = strchr(url, '/');
 346         return !colon || (slash && slash < colon) ||
 347                 has_dos_drive_prefix(url);
 348 }
 349
 350 static const char *prot_name(enum protocol protocol)
 351 {
 352         switch (protocol) {
 353                 case PROTO_LOCAL:
 354                 case PROTO_FILE:
 355                         return "file";
 356                 case PROTO_SSH:
 357                         return "ssh";
 358                 case PROTO_GIT:
 359                         return "git";
 360                 default:
 361                         return "unknown protocol";
 362         }
 363 }
 364
 365 static enum protocol get_protocol(const char *name)
 366 {
 367         if (!strcmp(name, "ssh"))
 368                 return PROTO_SSH;
 369         if (!strcmp(name, "git"))
 370                 return PROTO_GIT;
 371         if (!strcmp(name, "git+ssh")) /* deprecated - do not use */
 372                 return PROTO_SSH;
 373         if (!strcmp(name, "ssh+git")) /* deprecated - do not use */
 374                 return PROTO_SSH;
 375         if (!strcmp(name, "file"))
 376                 return PROTO_FILE;
 377         die("I don't handle protocol '%s'", name);
 378 }
 379
 380 static char *host_end(char **hoststart, int removebrackets)
 381 {
 382         char *host = *hoststart;
 383         char *end;
 384         char *start = strstr(host, "@[");
 385         if (start)
 386                 start++; /* Jump over '@' */
 387         else
 388                 start = host;
 389         if (start[0] == '[') {
 390                 end = strchr(start + 1, ']');
 391                 if (end) {
 392                         if (removebrackets) {
 393                                 *end = 0;
 394                                 memmove(start, start + 1, end - start);
 395                                 end++;
 396                         }
 397                 } else
 398                         end = host;
 399         } else
 400                 end = host;
 401         return end;
 402 }
 403
 404 #define STR_(s) # s
 405 #define STR(s)  STR_(s)
 406
 407 static void get_host_and_port(char **host, const char **port)
 408 {
 409         char *colon, *end;
 410         end = host_end(host, 1);
 411         colon = strchr(end, ':');
 412         if (colon) {
 413                 long portnr = strtol(colon + 1, &end, 10);
 414                 if (end != colon + 1 && *end == '\0' && 0 <= portnr && portnr < 65536) {
 415                         *colon = 0;
 416                         *port = colon + 1;
 417                 } else if (!colon[1]) {
 418                         *colon = 0;
 419                 }
 420         }
 421 }
 422
 423 static void enable_keepalive(int sockfd)
 424 {
 425         int ka = 1;
 426
 427         if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
 428                 fprintf(stderr, "unable to set SO_KEEPALIVE on socket: %s\n",
 429                         strerror(errno));
 430 }
 431
 432 #ifndef NO_IPV6
 433
 434 static const char *ai_name(const struct addrinfo *ai)
 435 {
 436         static char addr[NI_MAXHOST];
 437         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
 438                         NI_NUMERICHOST) != 0)
 439                 xsnprintf(addr, sizeof(addr), "(unknown)");
 440
 441         return addr;
 442 }
 443
 444 /*
 445  * Returns a connected socket() fd, or else die()s.
 446  */
 447 static int git_tcp_connect_sock(char *host, int flags)
 448 {
 449         struct strbuf error_message = STRBUF_INIT;
 450         int sockfd = -1;
 451         const char *port = STR(DEFAULT_GIT_PORT);
 452         struct addrinfo hints, *ai0, *ai;
 453         int gai;
 454         int cnt = 0;
 455
 456         get_host_and_port(&host, &port);
 457         if (!*port)
 458                 port = "<none>";
 459
 460         memset(&hints, 0, sizeof(hints));
 461         if (flags & CONNECT_IPV4)
 462                 hints.ai_family = AF_INET;
 463         else if (flags & CONNECT_IPV6)
 464                 hints.ai_family = AF_INET6;
 465         hints.ai_socktype = SOCK_STREAM;
 466         hints.ai_protocol = IPPROTO_TCP;
 467
 468         if (flags & CONNECT_VERBOSE)
 469                 fprintf(stderr, "Looking up %s ... ", host);
 470
 471         gai = getaddrinfo(host, port, &hints, &ai);
 472         if (gai)
 473                 die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
 474
 475         if (flags & CONNECT_VERBOSE)
 476                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 477
 478         for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
 479                 sockfd = socket(ai->ai_family,
 480                                 ai->ai_socktype, ai->ai_protocol);
 481                 if ((sockfd < 0) ||
 482                     (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
 483                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 484                                     host, cnt, ai_name(ai), strerror(errno));
 485                         if (0 <= sockfd)
 486                                 close(sockfd);
 487                         sockfd = -1;
 488                         continue;
 489                 }
 490                 if (flags & CONNECT_VERBOSE)
 491                         fprintf(stderr, "%s ", ai_name(ai));
 492                 break;
 493         }
 494
 495         freeaddrinfo(ai0);
 496
 497         if (sockfd < 0)
 498                 die("unable to connect to %s:\n%s", host, error_message.buf);
 499
 500         enable_keepalive(sockfd);
 501
 502         if (flags & CONNECT_VERBOSE)
 503                 fprintf(stderr, "done.\n");
 504
 505         strbuf_release(&error_message);
 506
 507         return sockfd;
 508 }
 509
 510 #else /* NO_IPV6 */
 511
 512 /*
 513  * Returns a connected socket() fd, or else die()s.
 514  */
 515 static int git_tcp_connect_sock(char *host, int flags)
 516 {
 517         struct strbuf error_message = STRBUF_INIT;
 518         int sockfd = -1;
 519         const char *port = STR(DEFAULT_GIT_PORT);
 520         char *ep;
 521         struct hostent *he;
 522         struct sockaddr_in sa;
 523         char **ap;
 524         unsigned int nport;
 525         int cnt;
 526
 527         get_host_and_port(&host, &port);
 528
 529         if (flags & CONNECT_VERBOSE)
 530                 fprintf(stderr, "Looking up %s ... ", host);
 531
 532         he = gethostbyname(host);
 533         if (!he)
 534                 die("Unable to look up %s (%s)", host, hstrerror(h_errno));
 535         nport = strtoul(port, &ep, 10);
 536         if ( ep == port || *ep ) {
 537                 /* Not numeric */
 538                 struct servent *se = getservbyname(port,"tcp");
 539                 if ( !se )
 540                         die("Unknown port %s", port);
 541                 nport = se->s_port;
 542         }
 543
 544         if (flags & CONNECT_VERBOSE)
 545                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 546
 547         for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
 548                 memset(&sa, 0, sizeof sa);
 549                 sa.sin_family = he->h_addrtype;
 550                 sa.sin_port = htons(nport);
 551                 memcpy(&sa.sin_addr, *ap, he->h_length);
 552
 553                 sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 554                 if ((sockfd < 0) ||
 555                     connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 556                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 557                                 host,
 558                                 cnt,
 559                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr),
 560                                 strerror(errno));
 561                         if (0 <= sockfd)
 562                                 close(sockfd);
 563                         sockfd = -1;
 564                         continue;
 565                 }
 566                 if (flags & CONNECT_VERBOSE)
 567                         fprintf(stderr, "%s ",
 568                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr));
 569                 break;
 570         }
 571
 572         if (sockfd < 0)
 573                 die("unable to connect to %s:\n%s", host, error_message.buf);
 574
 575         enable_keepalive(sockfd);
 576
 577         if (flags & CONNECT_VERBOSE)
 578                 fprintf(stderr, "done.\n");
 579
 580         return sockfd;
 581 }
 582
 583 #endif /* NO_IPV6 */
 584
 585
 586 /*
 587  * Dummy child_process returned by git_connect() if the transport protocol
 588  * does not need fork(2).
 589  */
 590 static struct child_process no_fork = CHILD_PROCESS_INIT;
 591
 592 int git_connection_is_socket(struct child_process *conn)
 593 {
 594         return conn == &no_fork;
 595 }
 596
 597 static struct child_process *git_tcp_connect(int fd[2], char *host, int flags)
 598 {
 599         int sockfd = git_tcp_connect_sock(host, flags);
 600
 601         fd[0] = sockfd;
 602         fd[1] = dup(sockfd);
 603
 604         return &no_fork;
 605 }
 606
 607
 608 static char *git_proxy_command;
 609
 610 static int git_proxy_command_options(const char *var, const char *value,
 611                 void *cb)
 612 {
 613         if (!strcmp(var, "core.gitproxy")) {
 614                 const char *for_pos;
 615                 int matchlen = -1;
 616                 int hostlen;
 617                 const char *rhost_name = cb;
 618                 int rhost_len = strlen(rhost_name);
 619
 620                 if (git_proxy_command)
 621                         return 0;
 622                 if (!value)
 623                         return config_error_nonbool(var);
 624                 /* [core]
 625                  * ;# matches www.kernel.org as well
 626                  * gitproxy = netcatter-1 for kernel.org
 627                  * gitproxy = netcatter-2 for sample.xz
 628                  * gitproxy = netcatter-default
 629                  */
 630                 for_pos = strstr(value, " for ");
 631                 if (!for_pos)
 632                         /* matches everybody */
 633                         matchlen = strlen(value);
 634                 else {
 635                         hostlen = strlen(for_pos + 5);
 636                         if (rhost_len < hostlen)
 637                                 matchlen = -1;
 638                         else if (!strncmp(for_pos + 5,
 639                                           rhost_name + rhost_len - hostlen,
 640                                           hostlen) &&
 641                                  ((rhost_len == hostlen) ||
 642                                   rhost_name[rhost_len - hostlen -1] == '.'))
 643                                 matchlen = for_pos - value;
 644                         else
 645                                 matchlen = -1;
 646                 }
 647                 if (0 <= matchlen) {
 648                         /* core.gitproxy = none for kernel.org */
 649                         if (matchlen == 4 &&
 650                             !memcmp(value, "none", 4))
 651                                 matchlen = 0;
 652                         git_proxy_command = xmemdupz(value, matchlen);
 653                 }
 654                 return 0;
 655         }
 656
 657         return git_default_config(var, value, cb);
 658 }
 659
 660 static int git_use_proxy(const char *host)
 661 {
 662         git_proxy_command = getenv("GIT_PROXY_COMMAND");
 663         git_config(git_proxy_command_options, (void*)host);
 664         return (git_proxy_command && *git_proxy_command);
 665 }
 666
 667 static struct child_process *git_proxy_connect(int fd[2], char *host)
 668 {
 669         const char *port = STR(DEFAULT_GIT_PORT);
 670         struct child_process *proxy;
 671
 672         get_host_and_port(&host, &port);
 673
 674         if (looks_like_command_line_option(host))
 675                 die("strange hostname '%s' blocked", host);
 676         if (looks_like_command_line_option(port))
 677                 die("strange port '%s' blocked", port);
 678
 679         proxy = xmalloc(sizeof(*proxy));
 680         child_process_init(proxy);
 681         argv_array_push(&proxy->args, git_proxy_command);
 682         argv_array_push(&proxy->args, host);
 683         argv_array_push(&proxy->args, port);
 684         proxy->in = -1;
 685         proxy->out = -1;
 686         if (start_command(proxy))
 687                 die("cannot start proxy %s", git_proxy_command);
 688         fd[0] = proxy->out; /* read from proxy stdout */
 689         fd[1] = proxy->in;  /* write to proxy stdin */
 690         return proxy;
 691 }
 692
 693 static char *get_port(char *host)
 694 {
 695         char *end;
 696         char *p = strchr(host, ':');
 697
 698         if (p) {
 699                 long port = strtol(p + 1, &end, 10);
 700                 if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
 701                         *p = '\0';
 702                         return p+1;
 703                 }
 704         }
 705
 706         return NULL;
 707 }
 708
 709 /*
 710  * Extract protocol and relevant parts from the specified connection URL.
 711  * The caller must free() the returned strings.
 712  */
 713 static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
 714                                        char **ret_path)
 715 {
 716         char *url;
 717         char *host, *path;
 718         char *end;
 719         int separator = '/';
 720         enum protocol protocol = PROTO_LOCAL;
 721
 722         if (is_url(url_orig))
 723                 url = url_decode(url_orig);
 724         else
 725                 url = xstrdup(url_orig);
 726
 727         host = strstr(url, "://");
 728         if (host) {
 729                 *host = '\0';
 730                 protocol = get_protocol(url);
 731                 host += 3;
 732         } else {
 733                 host = url;
 734                 if (!url_is_local_not_ssh(url)) {
 735                         protocol = PROTO_SSH;
 736                         separator = ':';
 737                 }
 738         }
 739
 740         /*
 741          * Don't do destructive transforms as protocol code does
 742          * '[]' unwrapping in get_host_and_port()
 743          */
 744         end = host_end(&host, 0);
 745
 746         if (protocol == PROTO_LOCAL)
 747                 path = end;
 748         else if (protocol == PROTO_FILE && has_dos_drive_prefix(end))
 749                 path = end; /* "file://$(pwd)" may be "file://C:/projects/repo" */
 750         else
 751                 path = strchr(end, separator);
 752
 753         if (!path || !*path)
 754                 die("No path specified. See 'man git-pull' for valid url syntax");
 755
 756         /*
 757          * null-terminate hostname and point path to ~ for URL's like this:
 758          *    ssh://host.xz/~user/repo
 759          */
 760
 761         end = path; /* Need to \0 terminate host here */
 762         if (separator == ':')
 763                 path++; /* path starts after ':' */
 764         if (protocol == PROTO_GIT || protocol == PROTO_SSH) {
 765                 if (path[1] == '~')
 766                         path++;
 767         }
 768
 769         path = xstrdup(path);
 770         *end = '\0';
 771
 772         *ret_host = xstrdup(host);
 773         *ret_path = path;
 774         free(url);
 775         return protocol;
 776 }
 777
 778 static const char *get_ssh_command(void)
 779 {
 780         const char *ssh;
 781
 782         if ((ssh = getenv("GIT_SSH_COMMAND")))
 783                 return ssh;
 784
 785         if (!git_config_get_string_const("core.sshcommand", &ssh))
 786                 return ssh;
 787
 788         return NULL;
 789 }
 790
 791 enum ssh_variant {
 792         VARIANT_AUTO,
 793         VARIANT_SIMPLE,
 794         VARIANT_SSH,
 795         VARIANT_PLINK,
 796         VARIANT_PUTTY,
 797         VARIANT_TORTOISEPLINK,
 798 };
 799
 800 static void override_ssh_variant(enum ssh_variant *ssh_variant)
 801 {
 802         const char *variant = getenv("GIT_SSH_VARIANT");
 803
 804         if (!variant && git_config_get_string_const("ssh.variant", &variant))
 805                 return;
 806
 807         if (!strcmp(variant, "auto"))
 808                 *ssh_variant = VARIANT_AUTO;
 809         else if (!strcmp(variant, "plink"))
 810                 *ssh_variant = VARIANT_PLINK;
 811         else if (!strcmp(variant, "putty"))
 812                 *ssh_variant = VARIANT_PUTTY;
 813         else if (!strcmp(variant, "tortoiseplink"))
 814                 *ssh_variant = VARIANT_TORTOISEPLINK;
 815         else if (!strcmp(variant, "simple"))
 816                 *ssh_variant = VARIANT_SIMPLE;
 817         else
 818                 *ssh_variant = VARIANT_SSH;
 819 }
 820
 821 static enum ssh_variant determine_ssh_variant(const char *ssh_command,
 822                                               int is_cmdline)
 823 {
 824         enum ssh_variant ssh_variant = VARIANT_AUTO;
 825         const char *variant;
 826         char *p = NULL;
 827
 828         override_ssh_variant(&ssh_variant);
 829
 830         if (ssh_variant != VARIANT_AUTO)
 831                 return ssh_variant;
 832
 833         if (!is_cmdline) {
 834                 p = xstrdup(ssh_command);
 835                 variant = basename(p);
 836         } else {
 837                 const char **ssh_argv;
 838
 839                 p = xstrdup(ssh_command);
 840                 if (split_cmdline(p, &ssh_argv) > 0) {
 841                         variant = basename((char *)ssh_argv[0]);
 842                         /*
 843                          * At this point, variant points into the buffer
 844                          * referenced by p, hence we do not need ssh_argv
 845                          * any longer.
 846                          */
 847                         free(ssh_argv);
 848                 } else {
 849                         free(p);
 850                         return ssh_variant;
 851                 }
 852         }
 853
 854         if (!strcasecmp(variant, "ssh") ||
 855             !strcasecmp(variant, "ssh.exe"))
 856                 ssh_variant = VARIANT_SSH;
 857         else if (!strcasecmp(variant, "plink") ||
 858                  !strcasecmp(variant, "plink.exe"))
 859                 ssh_variant = VARIANT_PLINK;
 860         else if (!strcasecmp(variant, "tortoiseplink") ||
 861                  !strcasecmp(variant, "tortoiseplink.exe"))
 862                 ssh_variant = VARIANT_TORTOISEPLINK;
 863
 864         free(p);
 865         return ssh_variant;
 866 }
 867
 868 /*
 869  * Open a connection using Git's native protocol.
 870  *
 871  * The caller is responsible for freeing hostandport, but this function may
 872  * modify it (for example, to truncate it to remove the port part).
 873  */
 874 static struct child_process *git_connect_git(int fd[2], char *hostandport,
 875                                              const char *path, const char *prog,
 876                                              int flags)
 877 {
 878         struct child_process *conn;
 879         struct strbuf request = STRBUF_INIT;
 880         /*
 881          * Set up virtual host information based on where we will
 882          * connect, unless the user has overridden us in
 883          * the environment.
 884          */
 885         char *target_host = getenv("GIT_OVERRIDE_VIRTUAL_HOST");
 886         if (target_host)
 887                 target_host = xstrdup(target_host);
 888         else
 889                 target_host = xstrdup(hostandport);
 890
 891         transport_check_allowed("git");
 892
 893         /*
 894          * These underlying connection commands die() if they
 895          * cannot connect.
 896          */
 897         if (git_use_proxy(hostandport))
 898                 conn = git_proxy_connect(fd, hostandport);
 899         else
 900                 conn = git_tcp_connect(fd, hostandport, flags);
 901         /*
 902          * Separate original protocol components prog and path
 903          * from extended host header with a NUL byte.
 904          *
 905          * Note: Do not add any other headers here!  Doing so
 906          * will cause older git-daemon servers to crash.
 907          */
 908         strbuf_addf(&request,
 909                     "%s %s%chost=%s%c",
 910                     prog, path, 0,
 911                     target_host, 0);
 912
 913         /* If using a new version put that stuff here after a second null byte */
 914         if (get_protocol_version_config() > 0) {
 915                 strbuf_addch(&request, '\0');
 916                 strbuf_addf(&request, "version=%d%c",
 917                             get_protocol_version_config(), '\0');
 918         }
 919
 920         packet_write(fd[1], request.buf, request.len);
 921
 922         free(target_host);
 923         strbuf_release(&request);
 924         return conn;
 925 }
 926
 927 /*
 928  * Append the appropriate environment variables to `env` and options to
 929  * `args` for running ssh in Git's SSH-tunneled transport.
 930  */
 931 static void push_ssh_options(struct argv_array *args, struct argv_array *env,
 932                              enum ssh_variant variant, const char *port,
 933                              int flags)
 934 {
 935         if (variant == VARIANT_SSH &&
 936             get_protocol_version_config() > 0) {
 937                 argv_array_push(args, "-o");
 938                 argv_array_push(args, "SendEnv=" GIT_PROTOCOL_ENVIRONMENT);
 939                 argv_array_pushf(env, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
 940                                  get_protocol_version_config());
 941         }
 942
 943         if (flags & CONNECT_IPV4) {
 944                 switch (variant) {
 945                 case VARIANT_AUTO:
 946                         BUG("VARIANT_AUTO passed to push_ssh_options");
 947                 case VARIANT_SIMPLE:
 948                         die("ssh variant 'simple' does not support -4");
 949                 case VARIANT_SSH:
 950                 case VARIANT_PLINK:
 951                 case VARIANT_PUTTY:
 952                 case VARIANT_TORTOISEPLINK:
 953                         argv_array_push(args, "-4");
 954                 }
 955         } else if (flags & CONNECT_IPV6) {
 956                 switch (variant) {
 957                 case VARIANT_AUTO:
 958                         BUG("VARIANT_AUTO passed to push_ssh_options");
 959                 case VARIANT_SIMPLE:
 960                         die("ssh variant 'simple' does not support -6");
 961                 case VARIANT_SSH:
 962                 case VARIANT_PLINK:
 963                 case VARIANT_PUTTY:
 964                 case VARIANT_TORTOISEPLINK:
 965                         argv_array_push(args, "-6");
 966                 }
 967         }
 968
 969         if (variant == VARIANT_TORTOISEPLINK)
 970                 argv_array_push(args, "-batch");
 971
 972         if (port) {
 973                 switch (variant) {
 974                 case VARIANT_AUTO:
 975                         BUG("VARIANT_AUTO passed to push_ssh_options");
 976                 case VARIANT_SIMPLE:
 977                         die("ssh variant 'simple' does not support setting port");
 978                 case VARIANT_SSH:
 979                         argv_array_push(args, "-p");
 980                         break;
 981                 case VARIANT_PLINK:
 982                 case VARIANT_PUTTY:
 983                 case VARIANT_TORTOISEPLINK:
 984                         argv_array_push(args, "-P");
 985                 }
 986
 987                 argv_array_push(args, port);
 988         }
 989 }
 990
 991 /* Prepare a child_process for use by Git's SSH-tunneled transport. */
 992 static void fill_ssh_args(struct child_process *conn, const char *ssh_host,
 993                           const char *port, int flags)
 994 {
 995         const char *ssh;
 996         enum ssh_variant variant;
 997
 998         if (looks_like_command_line_option(ssh_host))
 999                 die("strange hostname '%s' blocked", ssh_host);
1000
1001         ssh = get_ssh_command();
1002         if (ssh) {
1003                 variant = determine_ssh_variant(ssh, 1);
1004         } else {
1005                 /*
1006                  * GIT_SSH is the no-shell version of
1007                  * GIT_SSH_COMMAND (and must remain so for
1008                  * historical compatibility).
1009                  */
1010                 conn->use_shell = 0;
1011
1012                 ssh = getenv("GIT_SSH");
1013                 if (!ssh)
1014                         ssh = "ssh";
1015                 variant = determine_ssh_variant(ssh, 0);
1016         }
1017
1018         if (variant == VARIANT_AUTO) {
1019                 struct child_process detect = CHILD_PROCESS_INIT;
1020
1021                 detect.use_shell = conn->use_shell;
1022                 detect.no_stdin = detect.no_stdout = detect.no_stderr = 1;
1023
1024                 argv_array_push(&detect.args, ssh);
1025                 argv_array_push(&detect.args, "-G");
1026                 push_ssh_options(&detect.args, &detect.env_array,
1027                                  VARIANT_SSH, port, flags);
1028                 argv_array_push(&detect.args, ssh_host);
1029
1030                 variant = run_command(&detect) ? VARIANT_SIMPLE : VARIANT_SSH;
1031         }
1032
1033         argv_array_push(&conn->args, ssh);
1034         push_ssh_options(&conn->args, &conn->env_array, variant, port, flags);
1035         argv_array_push(&conn->args, ssh_host);
1036 }
1037
1038 /*
1039  * This returns the dummy child_process `no_fork` if the transport protocol
1040  * does not need fork(2), or a struct child_process object if it does.  Once
1041  * done, finish the connection with finish_connect() with the value returned
1042  * from this function (it is safe to call finish_connect() with NULL to
1043  * support the former case).
1044  *
1045  * If it returns, the connect is successful; it just dies on errors (this
1046  * will hopefully be changed in a libification effort, to return NULL when
1047  * the connection failed).
1048  */
1049 struct child_process *git_connect(int fd[2], const char *url,
1050                                   const char *prog, int flags)
1051 {
1052         char *hostandport, *path;
1053         struct child_process *conn;
1054         enum protocol protocol;
1055
1056         /* Without this we cannot rely on waitpid() to tell
1057          * what happened to our children.
1058          */
1059         signal(SIGCHLD, SIG_DFL);
1060
1061         protocol = parse_connect_url(url, &hostandport, &path);
1062         if ((flags & CONNECT_DIAG_URL) && (protocol != PROTO_SSH)) {
1063                 printf("Diag: url=%s\n", url ? url : "NULL");
1064                 printf("Diag: protocol=%s\n", prot_name(protocol));
1065                 printf("Diag: hostandport=%s\n", hostandport ? hostandport : "NULL");
1066                 printf("Diag: path=%s\n", path ? path : "NULL");
1067                 conn = NULL;
1068         } else if (protocol == PROTO_GIT) {
1069                 conn = git_connect_git(fd, hostandport, path, prog, flags);
1070         } else {
1071                 struct strbuf cmd = STRBUF_INIT;
1072                 const char *const *var;
1073
1074                 conn = xmalloc(sizeof(*conn));
1075                 child_process_init(conn);
1076
1077                 if (looks_like_command_line_option(path))
1078                         die("strange pathname '%s' blocked", path);
1079
1080                 strbuf_addstr(&cmd, prog);
1081                 strbuf_addch(&cmd, ' ');
1082                 sq_quote_buf(&cmd, path);
1083
1084                 /* remove repo-local variables from the environment */
1085                 for (var = local_repo_env; *var; var++)
1086                         argv_array_push(&conn->env_array, *var);
1087
1088                 conn->use_shell = 1;
1089                 conn->in = conn->out = -1;
1090                 if (protocol == PROTO_SSH) {
1091                         char *ssh_host = hostandport;
1092                         const char *port = NULL;
1093                         transport_check_allowed("ssh");
1094                         get_host_and_port(&ssh_host, &port);
1095
1096                         if (!port)
1097                                 port = get_port(ssh_host);
1098
1099                         if (flags & CONNECT_DIAG_URL) {
1100                                 printf("Diag: url=%s\n", url ? url : "NULL");
1101                                 printf("Diag: protocol=%s\n", prot_name(protocol));
1102                                 printf("Diag: userandhost=%s\n", ssh_host ? ssh_host : "NULL");
1103                                 printf("Diag: port=%s\n", port ? port : "NONE");
1104                                 printf("Diag: path=%s\n", path ? path : "NULL");
1105
1106                                 free(hostandport);
1107                                 free(path);
1108                                 free(conn);
1109                                 strbuf_release(&cmd);
1110                                 return NULL;
1111                         }
1112                         fill_ssh_args(conn, ssh_host, port, flags);
1113                 } else {
1114                         transport_check_allowed("file");
1115                         if (get_protocol_version_config() > 0) {
1116                                 argv_array_pushf(&conn->env_array, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
1117                                                  get_protocol_version_config());
1118                         }
1119                 }
1120                 argv_array_push(&conn->args, cmd.buf);
1121
1122                 if (start_command(conn))
1123                         die("unable to fork");
1124
1125                 fd[0] = conn->out; /* read from child's stdout */
1126                 fd[1] = conn->in;  /* write to child's stdin */
1127                 strbuf_release(&cmd);
1128         }
1129         free(hostandport);
1130         free(path);
1131         return conn;
1132 }
1133
1134 int finish_connect(struct child_process *conn)
1135 {
1136         int code;
1137         if (!conn || git_connection_is_socket(conn))
1138                 return 0;
1139
1140         code = finish_command(conn);
1141         free(conn);
1142         return code;
1143 }