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
  17 static char *server_capabilities;
  18 static const char *parse_feature_value(const char *, const char *, int *);
  19
  20 static int check_ref(const char *name, unsigned int flags)
  21 {
  22         if (!flags)
  23                 return 1;
  24
  25         if (!skip_prefix(name, "refs/", &name))
  26                 return 0;
  27
  28         /* REF_NORMAL means that we don't want the magic fake tag refs */
  29         if ((flags & REF_NORMAL) && check_refname_format(name, 0))
  30                 return 0;
  31
  32         /* REF_HEADS means that we want regular branch heads */
  33         if ((flags & REF_HEADS) && starts_with(name, "heads/"))
  34                 return 1;
  35
  36         /* REF_TAGS means that we want tags */
  37         if ((flags & REF_TAGS) && starts_with(name, "tags/"))
  38                 return 1;
  39
  40         /* All type bits clear means that we are ok with anything */
  41         return !(flags & ~REF_NORMAL);
  42 }
  43
  44 int check_ref_type(const struct ref *ref, int flags)
  45 {
  46         return check_ref(ref->name, flags);
  47 }
  48
  49 static void die_initial_contact(int unexpected)
  50 {
  51         /*
  52          * A hang-up after seeing some response from the other end
  53          * means that it is unexpected, as we know the other end is
  54          * willing to talk to us.  A hang-up before seeing any
  55          * response does not necessarily mean an ACL problem, though.
  56          */
  57         if (unexpected)
  58                 die(_("The remote end hung up upon initial contact"));
  59         else
  60                 die(_("Could not read from remote repository.\n\n"
  61                       "Please make sure you have the correct access rights\n"
  62                       "and the repository exists."));
  63 }
  64
  65 enum protocol_version discover_version(struct packet_reader *reader)
  66 {
  67         enum protocol_version version = protocol_unknown_version;
  68
  69         /*
  70          * Peek the first line of the server's response to
  71          * determine the protocol version the server is speaking.
  72          */
  73         switch (packet_reader_peek(reader)) {
  74         case PACKET_READ_EOF:
  75                 die_initial_contact(0);
  76         case PACKET_READ_FLUSH:
  77         case PACKET_READ_DELIM:
  78                 version = protocol_v0;
  79                 break;
  80         case PACKET_READ_NORMAL:
  81                 version = determine_protocol_version_client(reader->line);
  82                 break;
  83         }
  84
  85         switch (version) {
  86         case protocol_v2:
  87                 die("support for protocol v2 not implemented yet");
  88                 break;
  89         case protocol_v1:
  90                 /* Read the peeked version line */
  91                 packet_reader_read(reader);
  92                 break;
  93         case protocol_v0:
  94                 break;
  95         case protocol_unknown_version:
  96                 BUG("unknown protocol version");
  97         }
  98
  99         return version;
 100 }
 101
 102 static void parse_one_symref_info(struct string_list *symref, const char *val, int len)
 103 {
 104         char *sym, *target;
 105         struct string_list_item *item;
 106
 107         if (!len)
 108                 return; /* just "symref" */
 109         /* e.g. "symref=HEAD:refs/heads/master" */
 110         sym = xmemdupz(val, len);
 111         target = strchr(sym, ':');
 112         if (!target)
 113                 /* just "symref=something" */
 114                 goto reject;
 115         *(target++) = '\0';
 116         if (check_refname_format(sym, REFNAME_ALLOW_ONELEVEL) ||
 117             check_refname_format(target, REFNAME_ALLOW_ONELEVEL))
 118                 /* "symref=bogus:pair */
 119                 goto reject;
 120         item = string_list_append_nodup(symref, sym);
 121         item->util = target;
 122         return;
 123 reject:
 124         free(sym);
 125         return;
 126 }
 127
 128 static void annotate_refs_with_symref_info(struct ref *ref)
 129 {
 130         struct string_list symref = STRING_LIST_INIT_DUP;
 131         const char *feature_list = server_capabilities;
 132
 133         while (feature_list) {
 134                 int len;
 135                 const char *val;
 136
 137                 val = parse_feature_value(feature_list, "symref", &len);
 138                 if (!val)
 139                         break;
 140                 parse_one_symref_info(&symref, val, len);
 141                 feature_list = val + 1;
 142         }
 143         string_list_sort(&symref);
 144
 145         for (; ref; ref = ref->next) {
 146                 struct string_list_item *item;
 147                 item = string_list_lookup(&symref, ref->name);
 148                 if (!item)
 149                         continue;
 150                 ref->symref = xstrdup((char *)item->util);
 151         }
 152         string_list_clear(&symref, 0);
 153 }
 154
 155 static void process_capabilities(const char *line, int *len)
 156 {
 157         int nul_location = strlen(line);
 158         if (nul_location == *len)
 159                 return;
 160         server_capabilities = xstrdup(line + nul_location + 1);
 161         *len = nul_location;
 162 }
 163
 164 static int process_dummy_ref(const char *line)
 165 {
 166         struct object_id oid;
 167         const char *name;
 168
 169         if (parse_oid_hex(line, &oid, &name))
 170                 return 0;
 171         if (*name != ' ')
 172                 return 0;
 173         name++;
 174
 175         return !oidcmp(&null_oid, &oid) && !strcmp(name, "capabilities^{}");
 176 }
 177
 178 static void check_no_capabilities(const char *line, int len)
 179 {
 180         if (strlen(line) != len)
 181                 warning("Ignoring capabilities after first line '%s'",
 182                         line + strlen(line));
 183 }
 184
 185 static int process_ref(const char *line, int len, struct ref ***list,
 186                        unsigned int flags, struct oid_array *extra_have)
 187 {
 188         struct object_id old_oid;
 189         const char *name;
 190
 191         if (parse_oid_hex(line, &old_oid, &name))
 192                 return 0;
 193         if (*name != ' ')
 194                 return 0;
 195         name++;
 196
 197         if (extra_have && !strcmp(name, ".have")) {
 198                 oid_array_append(extra_have, &old_oid);
 199         } else if (!strcmp(name, "capabilities^{}")) {
 200                 die("protocol error: unexpected capabilities^{}");
 201         } else if (check_ref(name, flags)) {
 202                 struct ref *ref = alloc_ref(name);
 203                 oidcpy(&ref->old_oid, &old_oid);
 204                 **list = ref;
 205                 *list = &ref->next;
 206         }
 207         check_no_capabilities(line, len);
 208         return 1;
 209 }
 210
 211 static int process_shallow(const char *line, int len,
 212                            struct oid_array *shallow_points)
 213 {
 214         const char *arg;
 215         struct object_id old_oid;
 216
 217         if (!skip_prefix(line, "shallow ", &arg))
 218                 return 0;
 219
 220         if (get_oid_hex(arg, &old_oid))
 221                 die("protocol error: expected shallow sha-1, got '%s'", arg);
 222         if (!shallow_points)
 223                 die("repository on the other end cannot be shallow");
 224         oid_array_append(shallow_points, &old_oid);
 225         check_no_capabilities(line, len);
 226         return 1;
 227 }
 228
 229 enum get_remote_heads_state {
 230         EXPECTING_FIRST_REF = 0,
 231         EXPECTING_REF,
 232         EXPECTING_SHALLOW,
 233         EXPECTING_DONE,
 234 };
 235
 236 /*
 237  * Read all the refs from the other end
 238  */
 239 struct ref **get_remote_heads(struct packet_reader *reader,
 240                               struct ref **list, unsigned int flags,
 241                               struct oid_array *extra_have,
 242                               struct oid_array *shallow_points)
 243 {
 244         struct ref **orig_list = list;
 245         int len = 0;
 246         enum get_remote_heads_state state = EXPECTING_FIRST_REF;
 247         const char *arg;
 248
 249         *list = NULL;
 250
 251         while (state != EXPECTING_DONE) {
 252                 switch (packet_reader_read(reader)) {
 253                 case PACKET_READ_EOF:
 254                         die_initial_contact(1);
 255                 case PACKET_READ_NORMAL:
 256                         len = reader->pktlen;
 257                         if (len > 4 && skip_prefix(reader->line, "ERR ", &arg))
 258                                 die("remote error: %s", arg);
 259                         break;
 260                 case PACKET_READ_FLUSH:
 261                         state = EXPECTING_DONE;
 262                         break;
 263                 case PACKET_READ_DELIM:
 264                         die("invalid packet");
 265                 }
 266
 267                 switch (state) {
 268                 case EXPECTING_FIRST_REF:
 269                         process_capabilities(reader->line, &len);
 270                         if (process_dummy_ref(reader->line)) {
 271                                 state = EXPECTING_SHALLOW;
 272                                 break;
 273                         }
 274                         state = EXPECTING_REF;
 275                         /* fallthrough */
 276                 case EXPECTING_REF:
 277                         if (process_ref(reader->line, len, &list, flags, extra_have))
 278                                 break;
 279                         state = EXPECTING_SHALLOW;
 280                         /* fallthrough */
 281                 case EXPECTING_SHALLOW:
 282                         if (process_shallow(reader->line, len, shallow_points))
 283                                 break;
 284                         die("protocol error: unexpected '%s'", reader->line);
 285                 case EXPECTING_DONE:
 286                         break;
 287                 }
 288         }
 289
 290         annotate_refs_with_symref_info(*orig_list);
 291
 292         return list;
 293 }
 294
 295 static const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
 296 {
 297         int len;
 298
 299         if (!feature_list)
 300                 return NULL;
 301
 302         len = strlen(feature);
 303         while (*feature_list) {
 304                 const char *found = strstr(feature_list, feature);
 305                 if (!found)
 306                         return NULL;
 307                 if (feature_list == found || isspace(found[-1])) {
 308                         const char *value = found + len;
 309                         /* feature with no value (e.g., "thin-pack") */
 310                         if (!*value || isspace(*value)) {
 311                                 if (lenp)
 312                                         *lenp = 0;
 313                                 return value;
 314                         }
 315                         /* feature with a value (e.g., "agent=git/1.2.3") */
 316                         else if (*value == '=') {
 317                                 value++;
 318                                 if (lenp)
 319                                         *lenp = strcspn(value, " \t\n");
 320                                 return value;
 321                         }
 322                         /*
 323                          * otherwise we matched a substring of another feature;
 324                          * keep looking
 325                          */
 326                 }
 327                 feature_list = found + 1;
 328         }
 329         return NULL;
 330 }
 331
 332 int parse_feature_request(const char *feature_list, const char *feature)
 333 {
 334         return !!parse_feature_value(feature_list, feature, NULL);
 335 }
 336
 337 const char *server_feature_value(const char *feature, int *len)
 338 {
 339         return parse_feature_value(server_capabilities, feature, len);
 340 }
 341
 342 int server_supports(const char *feature)
 343 {
 344         return !!server_feature_value(feature, NULL);
 345 }
 346
 347 enum protocol {
 348         PROTO_LOCAL = 1,
 349         PROTO_FILE,
 350         PROTO_SSH,
 351         PROTO_GIT
 352 };
 353
 354 int url_is_local_not_ssh(const char *url)
 355 {
 356         const char *colon = strchr(url, ':');
 357         const char *slash = strchr(url, '/');
 358         return !colon || (slash && slash < colon) ||
 359                 has_dos_drive_prefix(url);
 360 }
 361
 362 static const char *prot_name(enum protocol protocol)
 363 {
 364         switch (protocol) {
 365                 case PROTO_LOCAL:
 366                 case PROTO_FILE:
 367                         return "file";
 368                 case PROTO_SSH:
 369                         return "ssh";
 370                 case PROTO_GIT:
 371                         return "git";
 372                 default:
 373                         return "unknown protocol";
 374         }
 375 }
 376
 377 static enum protocol get_protocol(const char *name)
 378 {
 379         if (!strcmp(name, "ssh"))
 380                 return PROTO_SSH;
 381         if (!strcmp(name, "git"))
 382                 return PROTO_GIT;
 383         if (!strcmp(name, "git+ssh")) /* deprecated - do not use */
 384                 return PROTO_SSH;
 385         if (!strcmp(name, "ssh+git")) /* deprecated - do not use */
 386                 return PROTO_SSH;
 387         if (!strcmp(name, "file"))
 388                 return PROTO_FILE;
 389         die("I don't handle protocol '%s'", name);
 390 }
 391
 392 static char *host_end(char **hoststart, int removebrackets)
 393 {
 394         char *host = *hoststart;
 395         char *end;
 396         char *start = strstr(host, "@[");
 397         if (start)
 398                 start++; /* Jump over '@' */
 399         else
 400                 start = host;
 401         if (start[0] == '[') {
 402                 end = strchr(start + 1, ']');
 403                 if (end) {
 404                         if (removebrackets) {
 405                                 *end = 0;
 406                                 memmove(start, start + 1, end - start);
 407                                 end++;
 408                         }
 409                 } else
 410                         end = host;
 411         } else
 412                 end = host;
 413         return end;
 414 }
 415
 416 #define STR_(s) # s
 417 #define STR(s)  STR_(s)
 418
 419 static void get_host_and_port(char **host, const char **port)
 420 {
 421         char *colon, *end;
 422         end = host_end(host, 1);
 423         colon = strchr(end, ':');
 424         if (colon) {
 425                 long portnr = strtol(colon + 1, &end, 10);
 426                 if (end != colon + 1 && *end == '\0' && 0 <= portnr && portnr < 65536) {
 427                         *colon = 0;
 428                         *port = colon + 1;
 429                 } else if (!colon[1]) {
 430                         *colon = 0;
 431                 }
 432         }
 433 }
 434
 435 static void enable_keepalive(int sockfd)
 436 {
 437         int ka = 1;
 438
 439         if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
 440                 fprintf(stderr, "unable to set SO_KEEPALIVE on socket: %s\n",
 441                         strerror(errno));
 442 }
 443
 444 #ifndef NO_IPV6
 445
 446 static const char *ai_name(const struct addrinfo *ai)
 447 {
 448         static char addr[NI_MAXHOST];
 449         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
 450                         NI_NUMERICHOST) != 0)
 451                 xsnprintf(addr, sizeof(addr), "(unknown)");
 452
 453         return addr;
 454 }
 455
 456 /*
 457  * Returns a connected socket() fd, or else die()s.
 458  */
 459 static int git_tcp_connect_sock(char *host, int flags)
 460 {
 461         struct strbuf error_message = STRBUF_INIT;
 462         int sockfd = -1;
 463         const char *port = STR(DEFAULT_GIT_PORT);
 464         struct addrinfo hints, *ai0, *ai;
 465         int gai;
 466         int cnt = 0;
 467
 468         get_host_and_port(&host, &port);
 469         if (!*port)
 470                 port = "<none>";
 471
 472         memset(&hints, 0, sizeof(hints));
 473         if (flags & CONNECT_IPV4)
 474                 hints.ai_family = AF_INET;
 475         else if (flags & CONNECT_IPV6)
 476                 hints.ai_family = AF_INET6;
 477         hints.ai_socktype = SOCK_STREAM;
 478         hints.ai_protocol = IPPROTO_TCP;
 479
 480         if (flags & CONNECT_VERBOSE)
 481                 fprintf(stderr, "Looking up %s ... ", host);
 482
 483         gai = getaddrinfo(host, port, &hints, &ai);
 484         if (gai)
 485                 die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
 486
 487         if (flags & CONNECT_VERBOSE)
 488                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 489
 490         for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
 491                 sockfd = socket(ai->ai_family,
 492                                 ai->ai_socktype, ai->ai_protocol);
 493                 if ((sockfd < 0) ||
 494                     (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
 495                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 496                                     host, cnt, ai_name(ai), strerror(errno));
 497                         if (0 <= sockfd)
 498                                 close(sockfd);
 499                         sockfd = -1;
 500                         continue;
 501                 }
 502                 if (flags & CONNECT_VERBOSE)
 503                         fprintf(stderr, "%s ", ai_name(ai));
 504                 break;
 505         }
 506
 507         freeaddrinfo(ai0);
 508
 509         if (sockfd < 0)
 510                 die("unable to connect to %s:\n%s", host, error_message.buf);
 511
 512         enable_keepalive(sockfd);
 513
 514         if (flags & CONNECT_VERBOSE)
 515                 fprintf(stderr, "done.\n");
 516
 517         strbuf_release(&error_message);
 518
 519         return sockfd;
 520 }
 521
 522 #else /* NO_IPV6 */
 523
 524 /*
 525  * Returns a connected socket() fd, or else die()s.
 526  */
 527 static int git_tcp_connect_sock(char *host, int flags)
 528 {
 529         struct strbuf error_message = STRBUF_INIT;
 530         int sockfd = -1;
 531         const char *port = STR(DEFAULT_GIT_PORT);
 532         char *ep;
 533         struct hostent *he;
 534         struct sockaddr_in sa;
 535         char **ap;
 536         unsigned int nport;
 537         int cnt;
 538
 539         get_host_and_port(&host, &port);
 540
 541         if (flags & CONNECT_VERBOSE)
 542                 fprintf(stderr, "Looking up %s ... ", host);
 543
 544         he = gethostbyname(host);
 545         if (!he)
 546                 die("Unable to look up %s (%s)", host, hstrerror(h_errno));
 547         nport = strtoul(port, &ep, 10);
 548         if ( ep == port || *ep ) {
 549                 /* Not numeric */
 550                 struct servent *se = getservbyname(port,"tcp");
 551                 if ( !se )
 552                         die("Unknown port %s", port);
 553                 nport = se->s_port;
 554         }
 555
 556         if (flags & CONNECT_VERBOSE)
 557                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 558
 559         for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
 560                 memset(&sa, 0, sizeof sa);
 561                 sa.sin_family = he->h_addrtype;
 562                 sa.sin_port = htons(nport);
 563                 memcpy(&sa.sin_addr, *ap, he->h_length);
 564
 565                 sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 566                 if ((sockfd < 0) ||
 567                     connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 568                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 569                                 host,
 570                                 cnt,
 571                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr),
 572                                 strerror(errno));
 573                         if (0 <= sockfd)
 574                                 close(sockfd);
 575                         sockfd = -1;
 576                         continue;
 577                 }
 578                 if (flags & CONNECT_VERBOSE)
 579                         fprintf(stderr, "%s ",
 580                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr));
 581                 break;
 582         }
 583
 584         if (sockfd < 0)
 585                 die("unable to connect to %s:\n%s", host, error_message.buf);
 586
 587         enable_keepalive(sockfd);
 588
 589         if (flags & CONNECT_VERBOSE)
 590                 fprintf(stderr, "done.\n");
 591
 592         return sockfd;
 593 }
 594
 595 #endif /* NO_IPV6 */
 596
 597
 598 /*
 599  * Dummy child_process returned by git_connect() if the transport protocol
 600  * does not need fork(2).
 601  */
 602 static struct child_process no_fork = CHILD_PROCESS_INIT;
 603
 604 int git_connection_is_socket(struct child_process *conn)
 605 {
 606         return conn == &no_fork;
 607 }
 608
 609 static struct child_process *git_tcp_connect(int fd[2], char *host, int flags)
 610 {
 611         int sockfd = git_tcp_connect_sock(host, flags);
 612
 613         fd[0] = sockfd;
 614         fd[1] = dup(sockfd);
 615
 616         return &no_fork;
 617 }
 618
 619
 620 static char *git_proxy_command;
 621
 622 static int git_proxy_command_options(const char *var, const char *value,
 623                 void *cb)
 624 {
 625         if (!strcmp(var, "core.gitproxy")) {
 626                 const char *for_pos;
 627                 int matchlen = -1;
 628                 int hostlen;
 629                 const char *rhost_name = cb;
 630                 int rhost_len = strlen(rhost_name);
 631
 632                 if (git_proxy_command)
 633                         return 0;
 634                 if (!value)
 635                         return config_error_nonbool(var);
 636                 /* [core]
 637                  * ;# matches www.kernel.org as well
 638                  * gitproxy = netcatter-1 for kernel.org
 639                  * gitproxy = netcatter-2 for sample.xz
 640                  * gitproxy = netcatter-default
 641                  */
 642                 for_pos = strstr(value, " for ");
 643                 if (!for_pos)
 644                         /* matches everybody */
 645                         matchlen = strlen(value);
 646                 else {
 647                         hostlen = strlen(for_pos + 5);
 648                         if (rhost_len < hostlen)
 649                                 matchlen = -1;
 650                         else if (!strncmp(for_pos + 5,
 651                                           rhost_name + rhost_len - hostlen,
 652                                           hostlen) &&
 653                                  ((rhost_len == hostlen) ||
 654                                   rhost_name[rhost_len - hostlen -1] == '.'))
 655                                 matchlen = for_pos - value;
 656                         else
 657                                 matchlen = -1;
 658                 }
 659                 if (0 <= matchlen) {
 660                         /* core.gitproxy = none for kernel.org */
 661                         if (matchlen == 4 &&
 662                             !memcmp(value, "none", 4))
 663                                 matchlen = 0;
 664                         git_proxy_command = xmemdupz(value, matchlen);
 665                 }
 666                 return 0;
 667         }
 668
 669         return git_default_config(var, value, cb);
 670 }
 671
 672 static int git_use_proxy(const char *host)
 673 {
 674         git_proxy_command = getenv("GIT_PROXY_COMMAND");
 675         git_config(git_proxy_command_options, (void*)host);
 676         return (git_proxy_command && *git_proxy_command);
 677 }
 678
 679 static struct child_process *git_proxy_connect(int fd[2], char *host)
 680 {
 681         const char *port = STR(DEFAULT_GIT_PORT);
 682         struct child_process *proxy;
 683
 684         get_host_and_port(&host, &port);
 685
 686         if (looks_like_command_line_option(host))
 687                 die("strange hostname '%s' blocked", host);
 688         if (looks_like_command_line_option(port))
 689                 die("strange port '%s' blocked", port);
 690
 691         proxy = xmalloc(sizeof(*proxy));
 692         child_process_init(proxy);
 693         argv_array_push(&proxy->args, git_proxy_command);
 694         argv_array_push(&proxy->args, host);
 695         argv_array_push(&proxy->args, port);
 696         proxy->in = -1;
 697         proxy->out = -1;
 698         if (start_command(proxy))
 699                 die("cannot start proxy %s", git_proxy_command);
 700         fd[0] = proxy->out; /* read from proxy stdout */
 701         fd[1] = proxy->in;  /* write to proxy stdin */
 702         return proxy;
 703 }
 704
 705 static char *get_port(char *host)
 706 {
 707         char *end;
 708         char *p = strchr(host, ':');
 709
 710         if (p) {
 711                 long port = strtol(p + 1, &end, 10);
 712                 if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
 713                         *p = '\0';
 714                         return p+1;
 715                 }
 716         }
 717
 718         return NULL;
 719 }
 720
 721 /*
 722  * Extract protocol and relevant parts from the specified connection URL.
 723  * The caller must free() the returned strings.
 724  */
 725 static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
 726                                        char **ret_path)
 727 {
 728         char *url;
 729         char *host, *path;
 730         char *end;
 731         int separator = '/';
 732         enum protocol protocol = PROTO_LOCAL;
 733
 734         if (is_url(url_orig))
 735                 url = url_decode(url_orig);
 736         else
 737                 url = xstrdup(url_orig);
 738
 739         host = strstr(url, "://");
 740         if (host) {
 741                 *host = '\0';
 742                 protocol = get_protocol(url);
 743                 host += 3;
 744         } else {
 745                 host = url;
 746                 if (!url_is_local_not_ssh(url)) {
 747                         protocol = PROTO_SSH;
 748                         separator = ':';
 749                 }
 750         }
 751
 752         /*
 753          * Don't do destructive transforms as protocol code does
 754          * '[]' unwrapping in get_host_and_port()
 755          */
 756         end = host_end(&host, 0);
 757
 758         if (protocol == PROTO_LOCAL)
 759                 path = end;
 760         else if (protocol == PROTO_FILE && has_dos_drive_prefix(end))
 761                 path = end; /* "file://$(pwd)" may be "file://C:/projects/repo" */
 762         else
 763                 path = strchr(end, separator);
 764
 765         if (!path || !*path)
 766                 die("No path specified. See 'man git-pull' for valid url syntax");
 767
 768         /*
 769          * null-terminate hostname and point path to ~ for URL's like this:
 770          *    ssh://host.xz/~user/repo
 771          */
 772
 773         end = path; /* Need to \0 terminate host here */
 774         if (separator == ':')
 775                 path++; /* path starts after ':' */
 776         if (protocol == PROTO_GIT || protocol == PROTO_SSH) {
 777                 if (path[1] == '~')
 778                         path++;
 779         }
 780
 781         path = xstrdup(path);
 782         *end = '\0';
 783
 784         *ret_host = xstrdup(host);
 785         *ret_path = path;
 786         free(url);
 787         return protocol;
 788 }
 789
 790 static const char *get_ssh_command(void)
 791 {
 792         const char *ssh;
 793
 794         if ((ssh = getenv("GIT_SSH_COMMAND")))
 795                 return ssh;
 796
 797         if (!git_config_get_string_const("core.sshcommand", &ssh))
 798                 return ssh;
 799
 800         return NULL;
 801 }
 802
 803 enum ssh_variant {
 804         VARIANT_AUTO,
 805         VARIANT_SIMPLE,
 806         VARIANT_SSH,
 807         VARIANT_PLINK,
 808         VARIANT_PUTTY,
 809         VARIANT_TORTOISEPLINK,
 810 };
 811
 812 static void override_ssh_variant(enum ssh_variant *ssh_variant)
 813 {
 814         const char *variant = getenv("GIT_SSH_VARIANT");
 815
 816         if (!variant && git_config_get_string_const("ssh.variant", &variant))
 817                 return;
 818
 819         if (!strcmp(variant, "auto"))
 820                 *ssh_variant = VARIANT_AUTO;
 821         else if (!strcmp(variant, "plink"))
 822                 *ssh_variant = VARIANT_PLINK;
 823         else if (!strcmp(variant, "putty"))
 824                 *ssh_variant = VARIANT_PUTTY;
 825         else if (!strcmp(variant, "tortoiseplink"))
 826                 *ssh_variant = VARIANT_TORTOISEPLINK;
 827         else if (!strcmp(variant, "simple"))
 828                 *ssh_variant = VARIANT_SIMPLE;
 829         else
 830                 *ssh_variant = VARIANT_SSH;
 831 }
 832
 833 static enum ssh_variant determine_ssh_variant(const char *ssh_command,
 834                                               int is_cmdline)
 835 {
 836         enum ssh_variant ssh_variant = VARIANT_AUTO;
 837         const char *variant;
 838         char *p = NULL;
 839
 840         override_ssh_variant(&ssh_variant);
 841
 842         if (ssh_variant != VARIANT_AUTO)
 843                 return ssh_variant;
 844
 845         if (!is_cmdline) {
 846                 p = xstrdup(ssh_command);
 847                 variant = basename(p);
 848         } else {
 849                 const char **ssh_argv;
 850
 851                 p = xstrdup(ssh_command);
 852                 if (split_cmdline(p, &ssh_argv) > 0) {
 853                         variant = basename((char *)ssh_argv[0]);
 854                         /*
 855                          * At this point, variant points into the buffer
 856                          * referenced by p, hence we do not need ssh_argv
 857                          * any longer.
 858                          */
 859                         free(ssh_argv);
 860                 } else {
 861                         free(p);
 862                         return ssh_variant;
 863                 }
 864         }
 865
 866         if (!strcasecmp(variant, "ssh") ||
 867             !strcasecmp(variant, "ssh.exe"))
 868                 ssh_variant = VARIANT_SSH;
 869         else if (!strcasecmp(variant, "plink") ||
 870                  !strcasecmp(variant, "plink.exe"))
 871                 ssh_variant = VARIANT_PLINK;
 872         else if (!strcasecmp(variant, "tortoiseplink") ||
 873                  !strcasecmp(variant, "tortoiseplink.exe"))
 874                 ssh_variant = VARIANT_TORTOISEPLINK;
 875
 876         free(p);
 877         return ssh_variant;
 878 }
 879
 880 /*
 881  * Open a connection using Git's native protocol.
 882  *
 883  * The caller is responsible for freeing hostandport, but this function may
 884  * modify it (for example, to truncate it to remove the port part).
 885  */
 886 static struct child_process *git_connect_git(int fd[2], char *hostandport,
 887                                              const char *path, const char *prog,
 888                                              int flags)
 889 {
 890         struct child_process *conn;
 891         struct strbuf request = STRBUF_INIT;
 892         /*
 893          * Set up virtual host information based on where we will
 894          * connect, unless the user has overridden us in
 895          * the environment.
 896          */
 897         char *target_host = getenv("GIT_OVERRIDE_VIRTUAL_HOST");
 898         if (target_host)
 899                 target_host = xstrdup(target_host);
 900         else
 901                 target_host = xstrdup(hostandport);
 902
 903         transport_check_allowed("git");
 904
 905         /*
 906          * These underlying connection commands die() if they
 907          * cannot connect.
 908          */
 909         if (git_use_proxy(hostandport))
 910                 conn = git_proxy_connect(fd, hostandport);
 911         else
 912                 conn = git_tcp_connect(fd, hostandport, flags);
 913         /*
 914          * Separate original protocol components prog and path
 915          * from extended host header with a NUL byte.
 916          *
 917          * Note: Do not add any other headers here!  Doing so
 918          * will cause older git-daemon servers to crash.
 919          */
 920         strbuf_addf(&request,
 921                     "%s %s%chost=%s%c",
 922                     prog, path, 0,
 923                     target_host, 0);
 924
 925         /* If using a new version put that stuff here after a second null byte */
 926         if (get_protocol_version_config() > 0) {
 927                 strbuf_addch(&request, '\0');
 928                 strbuf_addf(&request, "version=%d%c",
 929                             get_protocol_version_config(), '\0');
 930         }
 931
 932         packet_write(fd[1], request.buf, request.len);
 933
 934         free(target_host);
 935         strbuf_release(&request);
 936         return conn;
 937 }
 938
 939 /*
 940  * Append the appropriate environment variables to `env` and options to
 941  * `args` for running ssh in Git's SSH-tunneled transport.
 942  */
 943 static void push_ssh_options(struct argv_array *args, struct argv_array *env,
 944                              enum ssh_variant variant, const char *port,
 945                              int flags)
 946 {
 947         if (variant == VARIANT_SSH &&
 948             get_protocol_version_config() > 0) {
 949                 argv_array_push(args, "-o");
 950                 argv_array_push(args, "SendEnv=" GIT_PROTOCOL_ENVIRONMENT);
 951                 argv_array_pushf(env, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
 952                                  get_protocol_version_config());
 953         }
 954
 955         if (flags & CONNECT_IPV4) {
 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 -4");
 961                 case VARIANT_SSH:
 962                 case VARIANT_PLINK:
 963                 case VARIANT_PUTTY:
 964                 case VARIANT_TORTOISEPLINK:
 965                         argv_array_push(args, "-4");
 966                 }
 967         } else if (flags & CONNECT_IPV6) {
 968                 switch (variant) {
 969                 case VARIANT_AUTO:
 970                         BUG("VARIANT_AUTO passed to push_ssh_options");
 971                 case VARIANT_SIMPLE:
 972                         die("ssh variant 'simple' does not support -6");
 973                 case VARIANT_SSH:
 974                 case VARIANT_PLINK:
 975                 case VARIANT_PUTTY:
 976                 case VARIANT_TORTOISEPLINK:
 977                         argv_array_push(args, "-6");
 978                 }
 979         }
 980
 981         if (variant == VARIANT_TORTOISEPLINK)
 982                 argv_array_push(args, "-batch");
 983
 984         if (port) {
 985                 switch (variant) {
 986                 case VARIANT_AUTO:
 987                         BUG("VARIANT_AUTO passed to push_ssh_options");
 988                 case VARIANT_SIMPLE:
 989                         die("ssh variant 'simple' does not support setting port");
 990                 case VARIANT_SSH:
 991                         argv_array_push(args, "-p");
 992                         break;
 993                 case VARIANT_PLINK:
 994                 case VARIANT_PUTTY:
 995                 case VARIANT_TORTOISEPLINK:
 996                         argv_array_push(args, "-P");
 997                 }
 998
 999                 argv_array_push(args, port);
1000         }
1001 }
1002
1003 /* Prepare a child_process for use by Git's SSH-tunneled transport. */
1004 static void fill_ssh_args(struct child_process *conn, const char *ssh_host,
1005                           const char *port, int flags)
1006 {
1007         const char *ssh;
1008         enum ssh_variant variant;
1009
1010         if (looks_like_command_line_option(ssh_host))
1011                 die("strange hostname '%s' blocked", ssh_host);
1012
1013         ssh = get_ssh_command();
1014         if (ssh) {
1015                 variant = determine_ssh_variant(ssh, 1);
1016         } else {
1017                 /*
1018                  * GIT_SSH is the no-shell version of
1019                  * GIT_SSH_COMMAND (and must remain so for
1020                  * historical compatibility).
1021                  */
1022                 conn->use_shell = 0;
1023
1024                 ssh = getenv("GIT_SSH");
1025                 if (!ssh)
1026                         ssh = "ssh";
1027                 variant = determine_ssh_variant(ssh, 0);
1028         }
1029
1030         if (variant == VARIANT_AUTO) {
1031                 struct child_process detect = CHILD_PROCESS_INIT;
1032
1033                 detect.use_shell = conn->use_shell;
1034                 detect.no_stdin = detect.no_stdout = detect.no_stderr = 1;
1035
1036                 argv_array_push(&detect.args, ssh);
1037                 argv_array_push(&detect.args, "-G");
1038                 push_ssh_options(&detect.args, &detect.env_array,
1039                                  VARIANT_SSH, port, flags);
1040                 argv_array_push(&detect.args, ssh_host);
1041
1042                 variant = run_command(&detect) ? VARIANT_SIMPLE : VARIANT_SSH;
1043         }
1044
1045         argv_array_push(&conn->args, ssh);
1046         push_ssh_options(&conn->args, &conn->env_array, variant, port, flags);
1047         argv_array_push(&conn->args, ssh_host);
1048 }
1049
1050 /*
1051  * This returns the dummy child_process `no_fork` if the transport protocol
1052  * does not need fork(2), or a struct child_process object if it does.  Once
1053  * done, finish the connection with finish_connect() with the value returned
1054  * from this function (it is safe to call finish_connect() with NULL to
1055  * support the former case).
1056  *
1057  * If it returns, the connect is successful; it just dies on errors (this
1058  * will hopefully be changed in a libification effort, to return NULL when
1059  * the connection failed).
1060  */
1061 struct child_process *git_connect(int fd[2], const char *url,
1062                                   const char *prog, int flags)
1063 {
1064         char *hostandport, *path;
1065         struct child_process *conn;
1066         enum protocol protocol;
1067
1068         /* Without this we cannot rely on waitpid() to tell
1069          * what happened to our children.
1070          */
1071         signal(SIGCHLD, SIG_DFL);
1072
1073         protocol = parse_connect_url(url, &hostandport, &path);
1074         if ((flags & CONNECT_DIAG_URL) && (protocol != PROTO_SSH)) {
1075                 printf("Diag: url=%s\n", url ? url : "NULL");
1076                 printf("Diag: protocol=%s\n", prot_name(protocol));
1077                 printf("Diag: hostandport=%s\n", hostandport ? hostandport : "NULL");
1078                 printf("Diag: path=%s\n", path ? path : "NULL");
1079                 conn = NULL;
1080         } else if (protocol == PROTO_GIT) {
1081                 conn = git_connect_git(fd, hostandport, path, prog, flags);
1082         } else {
1083                 struct strbuf cmd = STRBUF_INIT;
1084                 const char *const *var;
1085
1086                 conn = xmalloc(sizeof(*conn));
1087                 child_process_init(conn);
1088
1089                 if (looks_like_command_line_option(path))
1090                         die("strange pathname '%s' blocked", path);
1091
1092                 strbuf_addstr(&cmd, prog);
1093                 strbuf_addch(&cmd, ' ');
1094                 sq_quote_buf(&cmd, path);
1095
1096                 /* remove repo-local variables from the environment */
1097                 for (var = local_repo_env; *var; var++)
1098                         argv_array_push(&conn->env_array, *var);
1099
1100                 conn->use_shell = 1;
1101                 conn->in = conn->out = -1;
1102                 if (protocol == PROTO_SSH) {
1103                         char *ssh_host = hostandport;
1104                         const char *port = NULL;
1105                         transport_check_allowed("ssh");
1106                         get_host_and_port(&ssh_host, &port);
1107
1108                         if (!port)
1109                                 port = get_port(ssh_host);
1110
1111                         if (flags & CONNECT_DIAG_URL) {
1112                                 printf("Diag: url=%s\n", url ? url : "NULL");
1113                                 printf("Diag: protocol=%s\n", prot_name(protocol));
1114                                 printf("Diag: userandhost=%s\n", ssh_host ? ssh_host : "NULL");
1115                                 printf("Diag: port=%s\n", port ? port : "NONE");
1116                                 printf("Diag: path=%s\n", path ? path : "NULL");
1117
1118                                 free(hostandport);
1119                                 free(path);
1120                                 free(conn);
1121                                 strbuf_release(&cmd);
1122                                 return NULL;
1123                         }
1124                         fill_ssh_args(conn, ssh_host, port, flags);
1125                 } else {
1126                         transport_check_allowed("file");
1127                         if (get_protocol_version_config() > 0) {
1128                                 argv_array_pushf(&conn->env_array, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
1129                                                  get_protocol_version_config());
1130                         }
1131                 }
1132                 argv_array_push(&conn->args, cmd.buf);
1133
1134                 if (start_command(conn))
1135                         die("unable to fork");
1136
1137                 fd[0] = conn->out; /* read from child's stdout */
1138                 fd[1] = conn->in;  /* write to child's stdin */
1139                 strbuf_release(&cmd);
1140         }
1141         free(hostandport);
1142         free(path);
1143         return conn;
1144 }
1145
1146 int finish_connect(struct child_process *conn)
1147 {
1148         int code;
1149         if (!conn || git_connection_is_socket(conn))
1150                 return 0;
1151
1152         code = finish_command(conn);
1153         free(conn);
1154         return code;
1155 }