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_v1:
  87                 /* Read the peeked version line */
  88                 packet_reader_read(reader);
  89                 break;
  90         case protocol_v0:
  91                 break;
  92         case protocol_unknown_version:
  93                 BUG("unknown protocol version");
  94         }
  95
  96         return version;
  97 }
  98
  99 static void parse_one_symref_info(struct string_list *symref, const char *val, int len)
 100 {
 101         char *sym, *target;
 102         struct string_list_item *item;
 103
 104         if (!len)
 105                 return; /* just "symref" */
 106         /* e.g. "symref=HEAD:refs/heads/master" */
 107         sym = xmemdupz(val, len);
 108         target = strchr(sym, ':');
 109         if (!target)
 110                 /* just "symref=something" */
 111                 goto reject;
 112         *(target++) = '\0';
 113         if (check_refname_format(sym, REFNAME_ALLOW_ONELEVEL) ||
 114             check_refname_format(target, REFNAME_ALLOW_ONELEVEL))
 115                 /* "symref=bogus:pair */
 116                 goto reject;
 117         item = string_list_append_nodup(symref, sym);
 118         item->util = target;
 119         return;
 120 reject:
 121         free(sym);
 122         return;
 123 }
 124
 125 static void annotate_refs_with_symref_info(struct ref *ref)
 126 {
 127         struct string_list symref = STRING_LIST_INIT_DUP;
 128         const char *feature_list = server_capabilities;
 129
 130         while (feature_list) {
 131                 int len;
 132                 const char *val;
 133
 134                 val = parse_feature_value(feature_list, "symref", &len);
 135                 if (!val)
 136                         break;
 137                 parse_one_symref_info(&symref, val, len);
 138                 feature_list = val + 1;
 139         }
 140         string_list_sort(&symref);
 141
 142         for (; ref; ref = ref->next) {
 143                 struct string_list_item *item;
 144                 item = string_list_lookup(&symref, ref->name);
 145                 if (!item)
 146                         continue;
 147                 ref->symref = xstrdup((char *)item->util);
 148         }
 149         string_list_clear(&symref, 0);
 150 }
 151
 152 static void process_capabilities(const char *line, int *len)
 153 {
 154         int nul_location = strlen(line);
 155         if (nul_location == *len)
 156                 return;
 157         server_capabilities = xstrdup(line + nul_location + 1);
 158         *len = nul_location;
 159 }
 160
 161 static int process_dummy_ref(const char *line)
 162 {
 163         struct object_id oid;
 164         const char *name;
 165
 166         if (parse_oid_hex(line, &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(const char *line, int len)
 176 {
 177         if (strlen(line) != len)
 178                 warning("Ignoring capabilities after first line '%s'",
 179                         line + strlen(line));
 180 }
 181
 182 static int process_ref(const char *line, int len, struct ref ***list,
 183                        unsigned int flags, struct oid_array *extra_have)
 184 {
 185         struct object_id old_oid;
 186         const char *name;
 187
 188         if (parse_oid_hex(line, &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(line, len);
 205         return 1;
 206 }
 207
 208 static int process_shallow(const char *line, int len,
 209                            struct oid_array *shallow_points)
 210 {
 211         const char *arg;
 212         struct object_id old_oid;
 213
 214         if (!skip_prefix(line, "shallow ", &arg))
 215                 return 0;
 216
 217         if (get_oid_hex(arg, &old_oid))
 218                 die("protocol error: expected shallow sha-1, got '%s'", arg);
 219         if (!shallow_points)
 220                 die("repository on the other end cannot be shallow");
 221         oid_array_append(shallow_points, &old_oid);
 222         check_no_capabilities(line, len);
 223         return 1;
 224 }
 225
 226 enum get_remote_heads_state {
 227         EXPECTING_FIRST_REF = 0,
 228         EXPECTING_REF,
 229         EXPECTING_SHALLOW,
 230         EXPECTING_DONE,
 231 };
 232
 233 /*
 234  * Read all the refs from the other end
 235  */
 236 struct ref **get_remote_heads(struct packet_reader *reader,
 237                               struct ref **list, unsigned int flags,
 238                               struct oid_array *extra_have,
 239                               struct oid_array *shallow_points)
 240 {
 241         struct ref **orig_list = list;
 242         int len = 0;
 243         enum get_remote_heads_state state = EXPECTING_FIRST_REF;
 244         const char *arg;
 245
 246         *list = NULL;
 247
 248         while (state != EXPECTING_DONE) {
 249                 switch (packet_reader_read(reader)) {
 250                 case PACKET_READ_EOF:
 251                         die_initial_contact(1);
 252                 case PACKET_READ_NORMAL:
 253                         len = reader->pktlen;
 254                         if (len > 4 && skip_prefix(reader->line, "ERR ", &arg))
 255                                 die("remote error: %s", arg);
 256                         break;
 257                 case PACKET_READ_FLUSH:
 258                         state = EXPECTING_DONE;
 259                         break;
 260                 case PACKET_READ_DELIM:
 261                         die("invalid packet");
 262                 }
 263
 264                 switch (state) {
 265                 case EXPECTING_FIRST_REF:
 266                         process_capabilities(reader->line, &len);
 267                         if (process_dummy_ref(reader->line)) {
 268                                 state = EXPECTING_SHALLOW;
 269                                 break;
 270                         }
 271                         state = EXPECTING_REF;
 272                         /* fallthrough */
 273                 case EXPECTING_REF:
 274                         if (process_ref(reader->line, len, &list, flags, extra_have))
 275                                 break;
 276                         state = EXPECTING_SHALLOW;
 277                         /* fallthrough */
 278                 case EXPECTING_SHALLOW:
 279                         if (process_shallow(reader->line, len, shallow_points))
 280                                 break;
 281                         die("protocol error: unexpected '%s'", reader->line);
 282                 case EXPECTING_DONE:
 283                         break;
 284                 }
 285         }
 286
 287         annotate_refs_with_symref_info(*orig_list);
 288
 289         return list;
 290 }
 291
 292 static const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
 293 {
 294         int len;
 295
 296         if (!feature_list)
 297                 return NULL;
 298
 299         len = strlen(feature);
 300         while (*feature_list) {
 301                 const char *found = strstr(feature_list, feature);
 302                 if (!found)
 303                         return NULL;
 304                 if (feature_list == found || isspace(found[-1])) {
 305                         const char *value = found + len;
 306                         /* feature with no value (e.g., "thin-pack") */
 307                         if (!*value || isspace(*value)) {
 308                                 if (lenp)
 309                                         *lenp = 0;
 310                                 return value;
 311                         }
 312                         /* feature with a value (e.g., "agent=git/1.2.3") */
 313                         else if (*value == '=') {
 314                                 value++;
 315                                 if (lenp)
 316                                         *lenp = strcspn(value, " \t\n");
 317                                 return value;
 318                         }
 319                         /*
 320                          * otherwise we matched a substring of another feature;
 321                          * keep looking
 322                          */
 323                 }
 324                 feature_list = found + 1;
 325         }
 326         return NULL;
 327 }
 328
 329 int parse_feature_request(const char *feature_list, const char *feature)
 330 {
 331         return !!parse_feature_value(feature_list, feature, NULL);
 332 }
 333
 334 const char *server_feature_value(const char *feature, int *len)
 335 {
 336         return parse_feature_value(server_capabilities, feature, len);
 337 }
 338
 339 int server_supports(const char *feature)
 340 {
 341         return !!server_feature_value(feature, NULL);
 342 }
 343
 344 enum protocol {
 345         PROTO_LOCAL = 1,
 346         PROTO_FILE,
 347         PROTO_SSH,
 348         PROTO_GIT
 349 };
 350
 351 int url_is_local_not_ssh(const char *url)
 352 {
 353         const char *colon = strchr(url, ':');
 354         const char *slash = strchr(url, '/');
 355         return !colon || (slash && slash < colon) ||
 356                 has_dos_drive_prefix(url);
 357 }
 358
 359 static const char *prot_name(enum protocol protocol)
 360 {
 361         switch (protocol) {
 362                 case PROTO_LOCAL:
 363                 case PROTO_FILE:
 364                         return "file";
 365                 case PROTO_SSH:
 366                         return "ssh";
 367                 case PROTO_GIT:
 368                         return "git";
 369                 default:
 370                         return "unknown protocol";
 371         }
 372 }
 373
 374 static enum protocol get_protocol(const char *name)
 375 {
 376         if (!strcmp(name, "ssh"))
 377                 return PROTO_SSH;
 378         if (!strcmp(name, "git"))
 379                 return PROTO_GIT;
 380         if (!strcmp(name, "git+ssh")) /* deprecated - do not use */
 381                 return PROTO_SSH;
 382         if (!strcmp(name, "ssh+git")) /* deprecated - do not use */
 383                 return PROTO_SSH;
 384         if (!strcmp(name, "file"))
 385                 return PROTO_FILE;
 386         die("I don't handle protocol '%s'", name);
 387 }
 388
 389 static char *host_end(char **hoststart, int removebrackets)
 390 {
 391         char *host = *hoststart;
 392         char *end;
 393         char *start = strstr(host, "@[");
 394         if (start)
 395                 start++; /* Jump over '@' */
 396         else
 397                 start = host;
 398         if (start[0] == '[') {
 399                 end = strchr(start + 1, ']');
 400                 if (end) {
 401                         if (removebrackets) {
 402                                 *end = 0;
 403                                 memmove(start, start + 1, end - start);
 404                                 end++;
 405                         }
 406                 } else
 407                         end = host;
 408         } else
 409                 end = host;
 410         return end;
 411 }
 412
 413 #define STR_(s) # s
 414 #define STR(s)  STR_(s)
 415
 416 static void get_host_and_port(char **host, const char **port)
 417 {
 418         char *colon, *end;
 419         end = host_end(host, 1);
 420         colon = strchr(end, ':');
 421         if (colon) {
 422                 long portnr = strtol(colon + 1, &end, 10);
 423                 if (end != colon + 1 && *end == '\0' && 0 <= portnr && portnr < 65536) {
 424                         *colon = 0;
 425                         *port = colon + 1;
 426                 } else if (!colon[1]) {
 427                         *colon = 0;
 428                 }
 429         }
 430 }
 431
 432 static void enable_keepalive(int sockfd)
 433 {
 434         int ka = 1;
 435
 436         if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
 437                 fprintf(stderr, "unable to set SO_KEEPALIVE on socket: %s\n",
 438                         strerror(errno));
 439 }
 440
 441 #ifndef NO_IPV6
 442
 443 static const char *ai_name(const struct addrinfo *ai)
 444 {
 445         static char addr[NI_MAXHOST];
 446         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
 447                         NI_NUMERICHOST) != 0)
 448                 xsnprintf(addr, sizeof(addr), "(unknown)");
 449
 450         return addr;
 451 }
 452
 453 /*
 454  * Returns a connected socket() fd, or else die()s.
 455  */
 456 static int git_tcp_connect_sock(char *host, int flags)
 457 {
 458         struct strbuf error_message = STRBUF_INIT;
 459         int sockfd = -1;
 460         const char *port = STR(DEFAULT_GIT_PORT);
 461         struct addrinfo hints, *ai0, *ai;
 462         int gai;
 463         int cnt = 0;
 464
 465         get_host_and_port(&host, &port);
 466         if (!*port)
 467                 port = "<none>";
 468
 469         memset(&hints, 0, sizeof(hints));
 470         if (flags & CONNECT_IPV4)
 471                 hints.ai_family = AF_INET;
 472         else if (flags & CONNECT_IPV6)
 473                 hints.ai_family = AF_INET6;
 474         hints.ai_socktype = SOCK_STREAM;
 475         hints.ai_protocol = IPPROTO_TCP;
 476
 477         if (flags & CONNECT_VERBOSE)
 478                 fprintf(stderr, "Looking up %s ... ", host);
 479
 480         gai = getaddrinfo(host, port, &hints, &ai);
 481         if (gai)
 482                 die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
 483
 484         if (flags & CONNECT_VERBOSE)
 485                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 486
 487         for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
 488                 sockfd = socket(ai->ai_family,
 489                                 ai->ai_socktype, ai->ai_protocol);
 490                 if ((sockfd < 0) ||
 491                     (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
 492                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 493                                     host, cnt, ai_name(ai), strerror(errno));
 494                         if (0 <= sockfd)
 495                                 close(sockfd);
 496                         sockfd = -1;
 497                         continue;
 498                 }
 499                 if (flags & CONNECT_VERBOSE)
 500                         fprintf(stderr, "%s ", ai_name(ai));
 501                 break;
 502         }
 503
 504         freeaddrinfo(ai0);
 505
 506         if (sockfd < 0)
 507                 die("unable to connect to %s:\n%s", host, error_message.buf);
 508
 509         enable_keepalive(sockfd);
 510
 511         if (flags & CONNECT_VERBOSE)
 512                 fprintf(stderr, "done.\n");
 513
 514         strbuf_release(&error_message);
 515
 516         return sockfd;
 517 }
 518
 519 #else /* NO_IPV6 */
 520
 521 /*
 522  * Returns a connected socket() fd, or else die()s.
 523  */
 524 static int git_tcp_connect_sock(char *host, int flags)
 525 {
 526         struct strbuf error_message = STRBUF_INIT;
 527         int sockfd = -1;
 528         const char *port = STR(DEFAULT_GIT_PORT);
 529         char *ep;
 530         struct hostent *he;
 531         struct sockaddr_in sa;
 532         char **ap;
 533         unsigned int nport;
 534         int cnt;
 535
 536         get_host_and_port(&host, &port);
 537
 538         if (flags & CONNECT_VERBOSE)
 539                 fprintf(stderr, "Looking up %s ... ", host);
 540
 541         he = gethostbyname(host);
 542         if (!he)
 543                 die("Unable to look up %s (%s)", host, hstrerror(h_errno));
 544         nport = strtoul(port, &ep, 10);
 545         if ( ep == port || *ep ) {
 546                 /* Not numeric */
 547                 struct servent *se = getservbyname(port,"tcp");
 548                 if ( !se )
 549                         die("Unknown port %s", port);
 550                 nport = se->s_port;
 551         }
 552
 553         if (flags & CONNECT_VERBOSE)
 554                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 555
 556         for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
 557                 memset(&sa, 0, sizeof sa);
 558                 sa.sin_family = he->h_addrtype;
 559                 sa.sin_port = htons(nport);
 560                 memcpy(&sa.sin_addr, *ap, he->h_length);
 561
 562                 sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 563                 if ((sockfd < 0) ||
 564                     connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 565                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 566                                 host,
 567                                 cnt,
 568                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr),
 569                                 strerror(errno));
 570                         if (0 <= sockfd)
 571                                 close(sockfd);
 572                         sockfd = -1;
 573                         continue;
 574                 }
 575                 if (flags & CONNECT_VERBOSE)
 576                         fprintf(stderr, "%s ",
 577                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr));
 578                 break;
 579         }
 580
 581         if (sockfd < 0)
 582                 die("unable to connect to %s:\n%s", host, error_message.buf);
 583
 584         enable_keepalive(sockfd);
 585
 586         if (flags & CONNECT_VERBOSE)
 587                 fprintf(stderr, "done.\n");
 588
 589         return sockfd;
 590 }
 591
 592 #endif /* NO_IPV6 */
 593
 594
 595 /*
 596  * Dummy child_process returned by git_connect() if the transport protocol
 597  * does not need fork(2).
 598  */
 599 static struct child_process no_fork = CHILD_PROCESS_INIT;
 600
 601 int git_connection_is_socket(struct child_process *conn)
 602 {
 603         return conn == &no_fork;
 604 }
 605
 606 static struct child_process *git_tcp_connect(int fd[2], char *host, int flags)
 607 {
 608         int sockfd = git_tcp_connect_sock(host, flags);
 609
 610         fd[0] = sockfd;
 611         fd[1] = dup(sockfd);
 612
 613         return &no_fork;
 614 }
 615
 616
 617 static char *git_proxy_command;
 618
 619 static int git_proxy_command_options(const char *var, const char *value,
 620                 void *cb)
 621 {
 622         if (!strcmp(var, "core.gitproxy")) {
 623                 const char *for_pos;
 624                 int matchlen = -1;
 625                 int hostlen;
 626                 const char *rhost_name = cb;
 627                 int rhost_len = strlen(rhost_name);
 628
 629                 if (git_proxy_command)
 630                         return 0;
 631                 if (!value)
 632                         return config_error_nonbool(var);
 633                 /* [core]
 634                  * ;# matches www.kernel.org as well
 635                  * gitproxy = netcatter-1 for kernel.org
 636                  * gitproxy = netcatter-2 for sample.xz
 637                  * gitproxy = netcatter-default
 638                  */
 639                 for_pos = strstr(value, " for ");
 640                 if (!for_pos)
 641                         /* matches everybody */
 642                         matchlen = strlen(value);
 643                 else {
 644                         hostlen = strlen(for_pos + 5);
 645                         if (rhost_len < hostlen)
 646                                 matchlen = -1;
 647                         else if (!strncmp(for_pos + 5,
 648                                           rhost_name + rhost_len - hostlen,
 649                                           hostlen) &&
 650                                  ((rhost_len == hostlen) ||
 651                                   rhost_name[rhost_len - hostlen -1] == '.'))
 652                                 matchlen = for_pos - value;
 653                         else
 654                                 matchlen = -1;
 655                 }
 656                 if (0 <= matchlen) {
 657                         /* core.gitproxy = none for kernel.org */
 658                         if (matchlen == 4 &&
 659                             !memcmp(value, "none", 4))
 660                                 matchlen = 0;
 661                         git_proxy_command = xmemdupz(value, matchlen);
 662                 }
 663                 return 0;
 664         }
 665
 666         return git_default_config(var, value, cb);
 667 }
 668
 669 static int git_use_proxy(const char *host)
 670 {
 671         git_proxy_command = getenv("GIT_PROXY_COMMAND");
 672         git_config(git_proxy_command_options, (void*)host);
 673         return (git_proxy_command && *git_proxy_command);
 674 }
 675
 676 static struct child_process *git_proxy_connect(int fd[2], char *host)
 677 {
 678         const char *port = STR(DEFAULT_GIT_PORT);
 679         struct child_process *proxy;
 680
 681         get_host_and_port(&host, &port);
 682
 683         if (looks_like_command_line_option(host))
 684                 die("strange hostname '%s' blocked", host);
 685         if (looks_like_command_line_option(port))
 686                 die("strange port '%s' blocked", port);
 687
 688         proxy = xmalloc(sizeof(*proxy));
 689         child_process_init(proxy);
 690         argv_array_push(&proxy->args, git_proxy_command);
 691         argv_array_push(&proxy->args, host);
 692         argv_array_push(&proxy->args, port);
 693         proxy->in = -1;
 694         proxy->out = -1;
 695         if (start_command(proxy))
 696                 die("cannot start proxy %s", git_proxy_command);
 697         fd[0] = proxy->out; /* read from proxy stdout */
 698         fd[1] = proxy->in;  /* write to proxy stdin */
 699         return proxy;
 700 }
 701
 702 static char *get_port(char *host)
 703 {
 704         char *end;
 705         char *p = strchr(host, ':');
 706
 707         if (p) {
 708                 long port = strtol(p + 1, &end, 10);
 709                 if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
 710                         *p = '\0';
 711                         return p+1;
 712                 }
 713         }
 714
 715         return NULL;
 716 }
 717
 718 /*
 719  * Extract protocol and relevant parts from the specified connection URL.
 720  * The caller must free() the returned strings.
 721  */
 722 static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
 723                                        char **ret_path)
 724 {
 725         char *url;
 726         char *host, *path;
 727         char *end;
 728         int separator = '/';
 729         enum protocol protocol = PROTO_LOCAL;
 730
 731         if (is_url(url_orig))
 732                 url = url_decode(url_orig);
 733         else
 734                 url = xstrdup(url_orig);
 735
 736         host = strstr(url, "://");
 737         if (host) {
 738                 *host = '\0';
 739                 protocol = get_protocol(url);
 740                 host += 3;
 741         } else {
 742                 host = url;
 743                 if (!url_is_local_not_ssh(url)) {
 744                         protocol = PROTO_SSH;
 745                         separator = ':';
 746                 }
 747         }
 748
 749         /*
 750          * Don't do destructive transforms as protocol code does
 751          * '[]' unwrapping in get_host_and_port()
 752          */
 753         end = host_end(&host, 0);
 754
 755         if (protocol == PROTO_LOCAL)
 756                 path = end;
 757         else if (protocol == PROTO_FILE && has_dos_drive_prefix(end))
 758                 path = end; /* "file://$(pwd)" may be "file://C:/projects/repo" */
 759         else
 760                 path = strchr(end, separator);
 761
 762         if (!path || !*path)
 763                 die("No path specified. See 'man git-pull' for valid url syntax");
 764
 765         /*
 766          * null-terminate hostname and point path to ~ for URL's like this:
 767          *    ssh://host.xz/~user/repo
 768          */
 769
 770         end = path; /* Need to \0 terminate host here */
 771         if (separator == ':')
 772                 path++; /* path starts after ':' */
 773         if (protocol == PROTO_GIT || protocol == PROTO_SSH) {
 774                 if (path[1] == '~')
 775                         path++;
 776         }
 777
 778         path = xstrdup(path);
 779         *end = '\0';
 780
 781         *ret_host = xstrdup(host);
 782         *ret_path = path;
 783         free(url);
 784         return protocol;
 785 }
 786
 787 static const char *get_ssh_command(void)
 788 {
 789         const char *ssh;
 790
 791         if ((ssh = getenv("GIT_SSH_COMMAND")))
 792                 return ssh;
 793
 794         if (!git_config_get_string_const("core.sshcommand", &ssh))
 795                 return ssh;
 796
 797         return NULL;
 798 }
 799
 800 enum ssh_variant {
 801         VARIANT_AUTO,
 802         VARIANT_SIMPLE,
 803         VARIANT_SSH,
 804         VARIANT_PLINK,
 805         VARIANT_PUTTY,
 806         VARIANT_TORTOISEPLINK,
 807 };
 808
 809 static void override_ssh_variant(enum ssh_variant *ssh_variant)
 810 {
 811         const char *variant = getenv("GIT_SSH_VARIANT");
 812
 813         if (!variant && git_config_get_string_const("ssh.variant", &variant))
 814                 return;
 815
 816         if (!strcmp(variant, "auto"))
 817                 *ssh_variant = VARIANT_AUTO;
 818         else if (!strcmp(variant, "plink"))
 819                 *ssh_variant = VARIANT_PLINK;
 820         else if (!strcmp(variant, "putty"))
 821                 *ssh_variant = VARIANT_PUTTY;
 822         else if (!strcmp(variant, "tortoiseplink"))
 823                 *ssh_variant = VARIANT_TORTOISEPLINK;
 824         else if (!strcmp(variant, "simple"))
 825                 *ssh_variant = VARIANT_SIMPLE;
 826         else
 827                 *ssh_variant = VARIANT_SSH;
 828 }
 829
 830 static enum ssh_variant determine_ssh_variant(const char *ssh_command,
 831                                               int is_cmdline)
 832 {
 833         enum ssh_variant ssh_variant = VARIANT_AUTO;
 834         const char *variant;
 835         char *p = NULL;
 836
 837         override_ssh_variant(&ssh_variant);
 838
 839         if (ssh_variant != VARIANT_AUTO)
 840                 return ssh_variant;
 841
 842         if (!is_cmdline) {
 843                 p = xstrdup(ssh_command);
 844                 variant = basename(p);
 845         } else {
 846                 const char **ssh_argv;
 847
 848                 p = xstrdup(ssh_command);
 849                 if (split_cmdline(p, &ssh_argv) > 0) {
 850                         variant = basename((char *)ssh_argv[0]);
 851                         /*
 852                          * At this point, variant points into the buffer
 853                          * referenced by p, hence we do not need ssh_argv
 854                          * any longer.
 855                          */
 856                         free(ssh_argv);
 857                 } else {
 858                         free(p);
 859                         return ssh_variant;
 860                 }
 861         }
 862
 863         if (!strcasecmp(variant, "ssh") ||
 864             !strcasecmp(variant, "ssh.exe"))
 865                 ssh_variant = VARIANT_SSH;
 866         else if (!strcasecmp(variant, "plink") ||
 867                  !strcasecmp(variant, "plink.exe"))
 868                 ssh_variant = VARIANT_PLINK;
 869         else if (!strcasecmp(variant, "tortoiseplink") ||
 870                  !strcasecmp(variant, "tortoiseplink.exe"))
 871                 ssh_variant = VARIANT_TORTOISEPLINK;
 872
 873         free(p);
 874         return ssh_variant;
 875 }
 876
 877 /*
 878  * Open a connection using Git's native protocol.
 879  *
 880  * The caller is responsible for freeing hostandport, but this function may
 881  * modify it (for example, to truncate it to remove the port part).
 882  */
 883 static struct child_process *git_connect_git(int fd[2], char *hostandport,
 884                                              const char *path, const char *prog,
 885                                              int flags)
 886 {
 887         struct child_process *conn;
 888         struct strbuf request = STRBUF_INIT;
 889         /*
 890          * Set up virtual host information based on where we will
 891          * connect, unless the user has overridden us in
 892          * the environment.
 893          */
 894         char *target_host = getenv("GIT_OVERRIDE_VIRTUAL_HOST");
 895         if (target_host)
 896                 target_host = xstrdup(target_host);
 897         else
 898                 target_host = xstrdup(hostandport);
 899
 900         transport_check_allowed("git");
 901
 902         /*
 903          * These underlying connection commands die() if they
 904          * cannot connect.
 905          */
 906         if (git_use_proxy(hostandport))
 907                 conn = git_proxy_connect(fd, hostandport);
 908         else
 909                 conn = git_tcp_connect(fd, hostandport, flags);
 910         /*
 911          * Separate original protocol components prog and path
 912          * from extended host header with a NUL byte.
 913          *
 914          * Note: Do not add any other headers here!  Doing so
 915          * will cause older git-daemon servers to crash.
 916          */
 917         strbuf_addf(&request,
 918                     "%s %s%chost=%s%c",
 919                     prog, path, 0,
 920                     target_host, 0);
 921
 922         /* If using a new version put that stuff here after a second null byte */
 923         if (get_protocol_version_config() > 0) {
 924                 strbuf_addch(&request, '\0');
 925                 strbuf_addf(&request, "version=%d%c",
 926                             get_protocol_version_config(), '\0');
 927         }
 928
 929         packet_write(fd[1], request.buf, request.len);
 930
 931         free(target_host);
 932         strbuf_release(&request);
 933         return conn;
 934 }
 935
 936 /*
 937  * Append the appropriate environment variables to `env` and options to
 938  * `args` for running ssh in Git's SSH-tunneled transport.
 939  */
 940 static void push_ssh_options(struct argv_array *args, struct argv_array *env,
 941                              enum ssh_variant variant, const char *port,
 942                              int flags)
 943 {
 944         if (variant == VARIANT_SSH &&
 945             get_protocol_version_config() > 0) {
 946                 argv_array_push(args, "-o");
 947                 argv_array_push(args, "SendEnv=" GIT_PROTOCOL_ENVIRONMENT);
 948                 argv_array_pushf(env, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
 949                                  get_protocol_version_config());
 950         }
 951
 952         if (flags & CONNECT_IPV4) {
 953                 switch (variant) {
 954                 case VARIANT_AUTO:
 955                         BUG("VARIANT_AUTO passed to push_ssh_options");
 956                 case VARIANT_SIMPLE:
 957                         die("ssh variant 'simple' does not support -4");
 958                 case VARIANT_SSH:
 959                 case VARIANT_PLINK:
 960                 case VARIANT_PUTTY:
 961                 case VARIANT_TORTOISEPLINK:
 962                         argv_array_push(args, "-4");
 963                 }
 964         } else if (flags & CONNECT_IPV6) {
 965                 switch (variant) {
 966                 case VARIANT_AUTO:
 967                         BUG("VARIANT_AUTO passed to push_ssh_options");
 968                 case VARIANT_SIMPLE:
 969                         die("ssh variant 'simple' does not support -6");
 970                 case VARIANT_SSH:
 971                 case VARIANT_PLINK:
 972                 case VARIANT_PUTTY:
 973                 case VARIANT_TORTOISEPLINK:
 974                         argv_array_push(args, "-6");
 975                 }
 976         }
 977
 978         if (variant == VARIANT_TORTOISEPLINK)
 979                 argv_array_push(args, "-batch");
 980
 981         if (port) {
 982                 switch (variant) {
 983                 case VARIANT_AUTO:
 984                         BUG("VARIANT_AUTO passed to push_ssh_options");
 985                 case VARIANT_SIMPLE:
 986                         die("ssh variant 'simple' does not support setting port");
 987                 case VARIANT_SSH:
 988                         argv_array_push(args, "-p");
 989                         break;
 990                 case VARIANT_PLINK:
 991                 case VARIANT_PUTTY:
 992                 case VARIANT_TORTOISEPLINK:
 993                         argv_array_push(args, "-P");
 994                 }
 995
 996                 argv_array_push(args, port);
 997         }
 998 }
 999
1000 /* Prepare a child_process for use by Git's SSH-tunneled transport. */
1001 static void fill_ssh_args(struct child_process *conn, const char *ssh_host,
1002                           const char *port, int flags)
1003 {
1004         const char *ssh;
1005         enum ssh_variant variant;
1006
1007         if (looks_like_command_line_option(ssh_host))
1008                 die("strange hostname '%s' blocked", ssh_host);
1009
1010         ssh = get_ssh_command();
1011         if (ssh) {
1012                 variant = determine_ssh_variant(ssh, 1);
1013         } else {
1014                 /*
1015                  * GIT_SSH is the no-shell version of
1016                  * GIT_SSH_COMMAND (and must remain so for
1017                  * historical compatibility).
1018                  */
1019                 conn->use_shell = 0;
1020
1021                 ssh = getenv("GIT_SSH");
1022                 if (!ssh)
1023                         ssh = "ssh";
1024                 variant = determine_ssh_variant(ssh, 0);
1025         }
1026
1027         if (variant == VARIANT_AUTO) {
1028                 struct child_process detect = CHILD_PROCESS_INIT;
1029
1030                 detect.use_shell = conn->use_shell;
1031                 detect.no_stdin = detect.no_stdout = detect.no_stderr = 1;
1032
1033                 argv_array_push(&detect.args, ssh);
1034                 argv_array_push(&detect.args, "-G");
1035                 push_ssh_options(&detect.args, &detect.env_array,
1036                                  VARIANT_SSH, port, flags);
1037                 argv_array_push(&detect.args, ssh_host);
1038
1039                 variant = run_command(&detect) ? VARIANT_SIMPLE : VARIANT_SSH;
1040         }
1041
1042         argv_array_push(&conn->args, ssh);
1043         push_ssh_options(&conn->args, &conn->env_array, variant, port, flags);
1044         argv_array_push(&conn->args, ssh_host);
1045 }
1046
1047 /*
1048  * This returns the dummy child_process `no_fork` if the transport protocol
1049  * does not need fork(2), or a struct child_process object if it does.  Once
1050  * done, finish the connection with finish_connect() with the value returned
1051  * from this function (it is safe to call finish_connect() with NULL to
1052  * support the former case).
1053  *
1054  * If it returns, the connect is successful; it just dies on errors (this
1055  * will hopefully be changed in a libification effort, to return NULL when
1056  * the connection failed).
1057  */
1058 struct child_process *git_connect(int fd[2], const char *url,
1059                                   const char *prog, int flags)
1060 {
1061         char *hostandport, *path;
1062         struct child_process *conn;
1063         enum protocol protocol;
1064
1065         /* Without this we cannot rely on waitpid() to tell
1066          * what happened to our children.
1067          */
1068         signal(SIGCHLD, SIG_DFL);
1069
1070         protocol = parse_connect_url(url, &hostandport, &path);
1071         if ((flags & CONNECT_DIAG_URL) && (protocol != PROTO_SSH)) {
1072                 printf("Diag: url=%s\n", url ? url : "NULL");
1073                 printf("Diag: protocol=%s\n", prot_name(protocol));
1074                 printf("Diag: hostandport=%s\n", hostandport ? hostandport : "NULL");
1075                 printf("Diag: path=%s\n", path ? path : "NULL");
1076                 conn = NULL;
1077         } else if (protocol == PROTO_GIT) {
1078                 conn = git_connect_git(fd, hostandport, path, prog, flags);
1079         } else {
1080                 struct strbuf cmd = STRBUF_INIT;
1081                 const char *const *var;
1082
1083                 conn = xmalloc(sizeof(*conn));
1084                 child_process_init(conn);
1085
1086                 if (looks_like_command_line_option(path))
1087                         die("strange pathname '%s' blocked", path);
1088
1089                 strbuf_addstr(&cmd, prog);
1090                 strbuf_addch(&cmd, ' ');
1091                 sq_quote_buf(&cmd, path);
1092
1093                 /* remove repo-local variables from the environment */
1094                 for (var = local_repo_env; *var; var++)
1095                         argv_array_push(&conn->env_array, *var);
1096
1097                 conn->use_shell = 1;
1098                 conn->in = conn->out = -1;
1099                 if (protocol == PROTO_SSH) {
1100                         char *ssh_host = hostandport;
1101                         const char *port = NULL;
1102                         transport_check_allowed("ssh");
1103                         get_host_and_port(&ssh_host, &port);
1104
1105                         if (!port)
1106                                 port = get_port(ssh_host);
1107
1108                         if (flags & CONNECT_DIAG_URL) {
1109                                 printf("Diag: url=%s\n", url ? url : "NULL");
1110                                 printf("Diag: protocol=%s\n", prot_name(protocol));
1111                                 printf("Diag: userandhost=%s\n", ssh_host ? ssh_host : "NULL");
1112                                 printf("Diag: port=%s\n", port ? port : "NONE");
1113                                 printf("Diag: path=%s\n", path ? path : "NULL");
1114
1115                                 free(hostandport);
1116                                 free(path);
1117                                 free(conn);
1118                                 strbuf_release(&cmd);
1119                                 return NULL;
1120                         }
1121                         fill_ssh_args(conn, ssh_host, port, flags);
1122                 } else {
1123                         transport_check_allowed("file");
1124                         if (get_protocol_version_config() > 0) {
1125                                 argv_array_pushf(&conn->env_array, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
1126                                                  get_protocol_version_config());
1127                         }
1128                 }
1129                 argv_array_push(&conn->args, cmd.buf);
1130
1131                 if (start_command(conn))
1132                         die("unable to fork");
1133
1134                 fd[0] = conn->out; /* read from child's stdout */
1135                 fd[1] = conn->in;  /* write to child's stdin */
1136                 strbuf_release(&cmd);
1137         }
1138         free(hostandport);
1139         free(path);
1140         return conn;
1141 }
1142
1143 int finish_connect(struct child_process *conn)
1144 {
1145         int code;
1146         if (!conn || git_connection_is_socket(conn))
1147                 return 0;
1148
1149         code = finish_command(conn);
1150         free(conn);
1151         return code;
1152 }