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 "version.h"
  16 #include "protocol.h"
  17 #include "alias.h"
  18
  19 static char *server_capabilities_v1;
  20 static struct argv_array server_capabilities_v2 = ARGV_ARRAY_INIT;
  21 static const char *parse_feature_value(const char *, const char *, int *);
  22
  23 static int check_ref(const char *name, unsigned int flags)
  24 {
  25         if (!flags)
  26                 return 1;
  27
  28         if (!skip_prefix(name, "refs/", &name))
  29                 return 0;
  30
  31         /* REF_NORMAL means that we don't want the magic fake tag refs */
  32         if ((flags & REF_NORMAL) && check_refname_format(name, 0))
  33                 return 0;
  34
  35         /* REF_HEADS means that we want regular branch heads */
  36         if ((flags & REF_HEADS) && starts_with(name, "heads/"))
  37                 return 1;
  38
  39         /* REF_TAGS means that we want tags */
  40         if ((flags & REF_TAGS) && starts_with(name, "tags/"))
  41                 return 1;
  42
  43         /* All type bits clear means that we are ok with anything */
  44         return !(flags & ~REF_NORMAL);
  45 }
  46
  47 int check_ref_type(const struct ref *ref, int flags)
  48 {
  49         return check_ref(ref->name, flags);
  50 }
  51
  52 static NORETURN void die_initial_contact(int unexpected)
  53 {
  54         /*
  55          * A hang-up after seeing some response from the other end
  56          * means that it is unexpected, as we know the other end is
  57          * willing to talk to us.  A hang-up before seeing any
  58          * response does not necessarily mean an ACL problem, though.
  59          */
  60         if (unexpected)
  61                 die(_("the remote end hung up upon initial contact"));
  62         else
  63                 die(_("Could not read from remote repository.\n\n"
  64                       "Please make sure you have the correct access rights\n"
  65                       "and the repository exists."));
  66 }
  67
  68 /* Checks if the server supports the capability 'c' */
  69 int server_supports_v2(const char *c, int die_on_error)
  70 {
  71         int i;
  72
  73         for (i = 0; i < server_capabilities_v2.argc; i++) {
  74                 const char *out;
  75                 if (skip_prefix(server_capabilities_v2.argv[i], c, &out) &&
  76                     (!*out || *out == '='))
  77                         return 1;
  78         }
  79
  80         if (die_on_error)
  81                 die(_("server doesn't support '%s'"), c);
  82
  83         return 0;
  84 }
  85
  86 int server_supports_feature(const char *c, const char *feature,
  87                             int die_on_error)
  88 {
  89         int i;
  90
  91         for (i = 0; i < server_capabilities_v2.argc; i++) {
  92                 const char *out;
  93                 if (skip_prefix(server_capabilities_v2.argv[i], c, &out) &&
  94                     (!*out || *(out++) == '=')) {
  95                         if (parse_feature_request(out, feature))
  96                                 return 1;
  97                         else
  98                                 break;
  99                 }
 100         }
 101
 102         if (die_on_error)
 103                 die(_("server doesn't support feature '%s'"), feature);
 104
 105         return 0;
 106 }
 107
 108 static void process_capabilities_v2(struct packet_reader *reader)
 109 {
 110         while (packet_reader_read(reader) == PACKET_READ_NORMAL)
 111                 argv_array_push(&server_capabilities_v2, reader->line);
 112
 113         if (reader->status != PACKET_READ_FLUSH)
 114                 die(_("expected flush after capabilities"));
 115 }
 116
 117 enum protocol_version discover_version(struct packet_reader *reader)
 118 {
 119         enum protocol_version version = protocol_unknown_version;
 120
 121         /*
 122          * Peek the first line of the server's response to
 123          * determine the protocol version the server is speaking.
 124          */
 125         switch (packet_reader_peek(reader)) {
 126         case PACKET_READ_EOF:
 127                 die_initial_contact(0);
 128         case PACKET_READ_FLUSH:
 129         case PACKET_READ_DELIM:
 130                 version = protocol_v0;
 131                 break;
 132         case PACKET_READ_NORMAL:
 133                 version = determine_protocol_version_client(reader->line);
 134                 break;
 135         }
 136
 137         switch (version) {
 138         case protocol_v2:
 139                 process_capabilities_v2(reader);
 140                 break;
 141         case protocol_v1:
 142                 /* Read the peeked version line */
 143                 packet_reader_read(reader);
 144                 break;
 145         case protocol_v0:
 146                 break;
 147         case protocol_unknown_version:
 148                 BUG("unknown protocol version");
 149         }
 150
 151         return version;
 152 }
 153
 154 static void parse_one_symref_info(struct string_list *symref, const char *val, int len)
 155 {
 156         char *sym, *target;
 157         struct string_list_item *item;
 158
 159         if (!len)
 160                 return; /* just "symref" */
 161         /* e.g. "symref=HEAD:refs/heads/master" */
 162         sym = xmemdupz(val, len);
 163         target = strchr(sym, ':');
 164         if (!target)
 165                 /* just "symref=something" */
 166                 goto reject;
 167         *(target++) = '\0';
 168         if (check_refname_format(sym, REFNAME_ALLOW_ONELEVEL) ||
 169             check_refname_format(target, REFNAME_ALLOW_ONELEVEL))
 170                 /* "symref=bogus:pair */
 171                 goto reject;
 172         item = string_list_append_nodup(symref, sym);
 173         item->util = target;
 174         return;
 175 reject:
 176         free(sym);
 177         return;
 178 }
 179
 180 static void annotate_refs_with_symref_info(struct ref *ref)
 181 {
 182         struct string_list symref = STRING_LIST_INIT_DUP;
 183         const char *feature_list = server_capabilities_v1;
 184
 185         while (feature_list) {
 186                 int len;
 187                 const char *val;
 188
 189                 val = parse_feature_value(feature_list, "symref", &len);
 190                 if (!val)
 191                         break;
 192                 parse_one_symref_info(&symref, val, len);
 193                 feature_list = val + 1;
 194         }
 195         string_list_sort(&symref);
 196
 197         for (; ref; ref = ref->next) {
 198                 struct string_list_item *item;
 199                 item = string_list_lookup(&symref, ref->name);
 200                 if (!item)
 201                         continue;
 202                 ref->symref = xstrdup((char *)item->util);
 203         }
 204         string_list_clear(&symref, 0);
 205 }
 206
 207 static void process_capabilities(const char *line, int *len)
 208 {
 209         int nul_location = strlen(line);
 210         if (nul_location == *len)
 211                 return;
 212         server_capabilities_v1 = xstrdup(line + nul_location + 1);
 213         *len = nul_location;
 214 }
 215
 216 static int process_dummy_ref(const char *line)
 217 {
 218         struct object_id oid;
 219         const char *name;
 220
 221         if (parse_oid_hex(line, &oid, &name))
 222                 return 0;
 223         if (*name != ' ')
 224                 return 0;
 225         name++;
 226
 227         return oideq(&null_oid, &oid) && !strcmp(name, "capabilities^{}");
 228 }
 229
 230 static void check_no_capabilities(const char *line, int len)
 231 {
 232         if (strlen(line) != len)
 233                 warning(_("ignoring capabilities after first line '%s'"),
 234                         line + strlen(line));
 235 }
 236
 237 static int process_ref(const char *line, int len, struct ref ***list,
 238                        unsigned int flags, struct oid_array *extra_have)
 239 {
 240         struct object_id old_oid;
 241         const char *name;
 242
 243         if (parse_oid_hex(line, &old_oid, &name))
 244                 return 0;
 245         if (*name != ' ')
 246                 return 0;
 247         name++;
 248
 249         if (extra_have && !strcmp(name, ".have")) {
 250                 oid_array_append(extra_have, &old_oid);
 251         } else if (!strcmp(name, "capabilities^{}")) {
 252                 die(_("protocol error: unexpected capabilities^{}"));
 253         } else if (check_ref(name, flags)) {
 254                 struct ref *ref = alloc_ref(name);
 255                 oidcpy(&ref->old_oid, &old_oid);
 256                 **list = ref;
 257                 *list = &ref->next;
 258         }
 259         check_no_capabilities(line, len);
 260         return 1;
 261 }
 262
 263 static int process_shallow(const char *line, int len,
 264                            struct oid_array *shallow_points)
 265 {
 266         const char *arg;
 267         struct object_id old_oid;
 268
 269         if (!skip_prefix(line, "shallow ", &arg))
 270                 return 0;
 271
 272         if (get_oid_hex(arg, &old_oid))
 273                 die(_("protocol error: expected shallow sha-1, got '%s'"), arg);
 274         if (!shallow_points)
 275                 die(_("repository on the other end cannot be shallow"));
 276         oid_array_append(shallow_points, &old_oid);
 277         check_no_capabilities(line, len);
 278         return 1;
 279 }
 280
 281 enum get_remote_heads_state {
 282         EXPECTING_FIRST_REF = 0,
 283         EXPECTING_REF,
 284         EXPECTING_SHALLOW,
 285         EXPECTING_DONE,
 286 };
 287
 288 /*
 289  * Read all the refs from the other end
 290  */
 291 struct ref **get_remote_heads(struct packet_reader *reader,
 292                               struct ref **list, unsigned int flags,
 293                               struct oid_array *extra_have,
 294                               struct oid_array *shallow_points)
 295 {
 296         struct ref **orig_list = list;
 297         int len = 0;
 298         enum get_remote_heads_state state = EXPECTING_FIRST_REF;
 299
 300         *list = NULL;
 301
 302         while (state != EXPECTING_DONE) {
 303                 switch (packet_reader_read(reader)) {
 304                 case PACKET_READ_EOF:
 305                         die_initial_contact(1);
 306                 case PACKET_READ_NORMAL:
 307                         len = reader->pktlen;
 308                         break;
 309                 case PACKET_READ_FLUSH:
 310                         state = EXPECTING_DONE;
 311                         break;
 312                 case PACKET_READ_DELIM:
 313                         die(_("invalid packet"));
 314                 }
 315
 316                 switch (state) {
 317                 case EXPECTING_FIRST_REF:
 318                         process_capabilities(reader->line, &len);
 319                         if (process_dummy_ref(reader->line)) {
 320                                 state = EXPECTING_SHALLOW;
 321                                 break;
 322                         }
 323                         state = EXPECTING_REF;
 324                         /* fallthrough */
 325                 case EXPECTING_REF:
 326                         if (process_ref(reader->line, len, &list, flags, extra_have))
 327                                 break;
 328                         state = EXPECTING_SHALLOW;
 329                         /* fallthrough */
 330                 case EXPECTING_SHALLOW:
 331                         if (process_shallow(reader->line, len, shallow_points))
 332                                 break;
 333                         die(_("protocol error: unexpected '%s'"), reader->line);
 334                 case EXPECTING_DONE:
 335                         break;
 336                 }
 337         }
 338
 339         annotate_refs_with_symref_info(*orig_list);
 340
 341         return list;
 342 }
 343
 344 /* Returns 1 when a valid ref has been added to `list`, 0 otherwise */
 345 static int process_ref_v2(const char *line, struct ref ***list)
 346 {
 347         int ret = 1;
 348         int i = 0;
 349         struct object_id old_oid;
 350         struct ref *ref;
 351         struct string_list line_sections = STRING_LIST_INIT_DUP;
 352         const char *end;
 353
 354         /*
 355          * Ref lines have a number of fields which are space deliminated.  The
 356          * first field is the OID of the ref.  The second field is the ref
 357          * name.  Subsequent fields (symref-target and peeled) are optional and
 358          * don't have a particular order.
 359          */
 360         if (string_list_split(&line_sections, line, ' ', -1) < 2) {
 361                 ret = 0;
 362                 goto out;
 363         }
 364
 365         if (parse_oid_hex(line_sections.items[i++].string, &old_oid, &end) ||
 366             *end) {
 367                 ret = 0;
 368                 goto out;
 369         }
 370
 371         ref = alloc_ref(line_sections.items[i++].string);
 372
 373         oidcpy(&ref->old_oid, &old_oid);
 374         **list = ref;
 375         *list = &ref->next;
 376
 377         for (; i < line_sections.nr; i++) {
 378                 const char *arg = line_sections.items[i].string;
 379                 if (skip_prefix(arg, "symref-target:", &arg))
 380                         ref->symref = xstrdup(arg);
 381
 382                 if (skip_prefix(arg, "peeled:", &arg)) {
 383                         struct object_id peeled_oid;
 384                         char *peeled_name;
 385                         struct ref *peeled;
 386                         if (parse_oid_hex(arg, &peeled_oid, &end) || *end) {
 387                                 ret = 0;
 388                                 goto out;
 389                         }
 390
 391                         peeled_name = xstrfmt("%s^{}", ref->name);
 392                         peeled = alloc_ref(peeled_name);
 393
 394                         oidcpy(&peeled->old_oid, &peeled_oid);
 395                         **list = peeled;
 396                         *list = &peeled->next;
 397
 398                         free(peeled_name);
 399                 }
 400         }
 401
 402 out:
 403         string_list_clear(&line_sections, 0);
 404         return ret;
 405 }
 406
 407 struct ref **get_remote_refs(int fd_out, struct packet_reader *reader,
 408                              struct ref **list, int for_push,
 409                              const struct argv_array *ref_prefixes,
 410                              const struct string_list *server_options)
 411 {
 412         int i;
 413         *list = NULL;
 414
 415         if (server_supports_v2("ls-refs", 1))
 416                 packet_write_fmt(fd_out, "command=ls-refs\n");
 417
 418         if (server_supports_v2("agent", 0))
 419                 packet_write_fmt(fd_out, "agent=%s", git_user_agent_sanitized());
 420
 421         if (server_options && server_options->nr &&
 422             server_supports_v2("server-option", 1))
 423                 for (i = 0; i < server_options->nr; i++)
 424                         packet_write_fmt(fd_out, "server-option=%s",
 425                                          server_options->items[i].string);
 426
 427         packet_delim(fd_out);
 428         /* When pushing we don't want to request the peeled tags */
 429         if (!for_push)
 430                 packet_write_fmt(fd_out, "peel\n");
 431         packet_write_fmt(fd_out, "symrefs\n");
 432         for (i = 0; ref_prefixes && i < ref_prefixes->argc; i++) {
 433                 packet_write_fmt(fd_out, "ref-prefix %s\n",
 434                                  ref_prefixes->argv[i]);
 435         }
 436         packet_flush(fd_out);
 437
 438         /* Process response from server */
 439         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
 440                 if (!process_ref_v2(reader->line, &list))
 441                         die(_("invalid ls-refs response: %s"), reader->line);
 442         }
 443
 444         if (reader->status != PACKET_READ_FLUSH)
 445                 die(_("expected flush after ref listing"));
 446
 447         return list;
 448 }
 449
 450 static const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
 451 {
 452         int len;
 453
 454         if (!feature_list)
 455                 return NULL;
 456
 457         len = strlen(feature);
 458         while (*feature_list) {
 459                 const char *found = strstr(feature_list, feature);
 460                 if (!found)
 461                         return NULL;
 462                 if (feature_list == found || isspace(found[-1])) {
 463                         const char *value = found + len;
 464                         /* feature with no value (e.g., "thin-pack") */
 465                         if (!*value || isspace(*value)) {
 466                                 if (lenp)
 467                                         *lenp = 0;
 468                                 return value;
 469                         }
 470                         /* feature with a value (e.g., "agent=git/1.2.3") */
 471                         else if (*value == '=') {
 472                                 value++;
 473                                 if (lenp)
 474                                         *lenp = strcspn(value, " \t\n");
 475                                 return value;
 476                         }
 477                         /*
 478                          * otherwise we matched a substring of another feature;
 479                          * keep looking
 480                          */
 481                 }
 482                 feature_list = found + 1;
 483         }
 484         return NULL;
 485 }
 486
 487 int parse_feature_request(const char *feature_list, const char *feature)
 488 {
 489         return !!parse_feature_value(feature_list, feature, NULL);
 490 }
 491
 492 const char *server_feature_value(const char *feature, int *len)
 493 {
 494         return parse_feature_value(server_capabilities_v1, feature, len);
 495 }
 496
 497 int server_supports(const char *feature)
 498 {
 499         return !!server_feature_value(feature, NULL);
 500 }
 501
 502 enum protocol {
 503         PROTO_LOCAL = 1,
 504         PROTO_FILE,
 505         PROTO_SSH,
 506         PROTO_GIT
 507 };
 508
 509 int url_is_local_not_ssh(const char *url)
 510 {
 511         const char *colon = strchr(url, ':');
 512         const char *slash = strchr(url, '/');
 513         return !colon || (slash && slash < colon) ||
 514                 has_dos_drive_prefix(url);
 515 }
 516
 517 static const char *prot_name(enum protocol protocol)
 518 {
 519         switch (protocol) {
 520                 case PROTO_LOCAL:
 521                 case PROTO_FILE:
 522                         return "file";
 523                 case PROTO_SSH:
 524                         return "ssh";
 525                 case PROTO_GIT:
 526                         return "git";
 527                 default:
 528                         return "unknown protocol";
 529         }
 530 }
 531
 532 static enum protocol get_protocol(const char *name)
 533 {
 534         if (!strcmp(name, "ssh"))
 535                 return PROTO_SSH;
 536         if (!strcmp(name, "git"))
 537                 return PROTO_GIT;
 538         if (!strcmp(name, "git+ssh")) /* deprecated - do not use */
 539                 return PROTO_SSH;
 540         if (!strcmp(name, "ssh+git")) /* deprecated - do not use */
 541                 return PROTO_SSH;
 542         if (!strcmp(name, "file"))
 543                 return PROTO_FILE;
 544         die(_("protocol '%s' is not supported"), name);
 545 }
 546
 547 static char *host_end(char **hoststart, int removebrackets)
 548 {
 549         char *host = *hoststart;
 550         char *end;
 551         char *start = strstr(host, "@[");
 552         if (start)
 553                 start++; /* Jump over '@' */
 554         else
 555                 start = host;
 556         if (start[0] == '[') {
 557                 end = strchr(start + 1, ']');
 558                 if (end) {
 559                         if (removebrackets) {
 560                                 *end = 0;
 561                                 memmove(start, start + 1, end - start);
 562                                 end++;
 563                         }
 564                 } else
 565                         end = host;
 566         } else
 567                 end = host;
 568         return end;
 569 }
 570
 571 #define STR_(s) # s
 572 #define STR(s)  STR_(s)
 573
 574 static void get_host_and_port(char **host, const char **port)
 575 {
 576         char *colon, *end;
 577         end = host_end(host, 1);
 578         colon = strchr(end, ':');
 579         if (colon) {
 580                 long portnr = strtol(colon + 1, &end, 10);
 581                 if (end != colon + 1 && *end == '\0' && 0 <= portnr && portnr < 65536) {
 582                         *colon = 0;
 583                         *port = colon + 1;
 584                 } else if (!colon[1]) {
 585                         *colon = 0;
 586                 }
 587         }
 588 }
 589
 590 static void enable_keepalive(int sockfd)
 591 {
 592         int ka = 1;
 593
 594         if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
 595                 error_errno(_("unable to set SO_KEEPALIVE on socket"));
 596 }
 597
 598 #ifndef NO_IPV6
 599
 600 static const char *ai_name(const struct addrinfo *ai)
 601 {
 602         static char addr[NI_MAXHOST];
 603         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
 604                         NI_NUMERICHOST) != 0)
 605                 xsnprintf(addr, sizeof(addr), "(unknown)");
 606
 607         return addr;
 608 }
 609
 610 /*
 611  * Returns a connected socket() fd, or else die()s.
 612  */
 613 static int git_tcp_connect_sock(char *host, int flags)
 614 {
 615         struct strbuf error_message = STRBUF_INIT;
 616         int sockfd = -1;
 617         const char *port = STR(DEFAULT_GIT_PORT);
 618         struct addrinfo hints, *ai0, *ai;
 619         int gai;
 620         int cnt = 0;
 621
 622         get_host_and_port(&host, &port);
 623         if (!*port)
 624                 port = "<none>";
 625
 626         memset(&hints, 0, sizeof(hints));
 627         if (flags & CONNECT_IPV4)
 628                 hints.ai_family = AF_INET;
 629         else if (flags & CONNECT_IPV6)
 630                 hints.ai_family = AF_INET6;
 631         hints.ai_socktype = SOCK_STREAM;
 632         hints.ai_protocol = IPPROTO_TCP;
 633
 634         if (flags & CONNECT_VERBOSE)
 635                 fprintf(stderr, _("Looking up %s ... "), host);
 636
 637         gai = getaddrinfo(host, port, &hints, &ai);
 638         if (gai)
 639                 die(_("unable to look up %s (port %s) (%s)"), host, port, gai_strerror(gai));
 640
 641         if (flags & CONNECT_VERBOSE)
 642                 /* TRANSLATORS: this is the end of "Looking up %s ... " */
 643                 fprintf(stderr, _("done.\nConnecting to %s (port %s) ... "), host, port);
 644
 645         for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
 646                 sockfd = socket(ai->ai_family,
 647                                 ai->ai_socktype, ai->ai_protocol);
 648                 if ((sockfd < 0) ||
 649                     (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
 650                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 651                                     host, cnt, ai_name(ai), strerror(errno));
 652                         if (0 <= sockfd)
 653                                 close(sockfd);
 654                         sockfd = -1;
 655                         continue;
 656                 }
 657                 if (flags & CONNECT_VERBOSE)
 658                         fprintf(stderr, "%s ", ai_name(ai));
 659                 break;
 660         }
 661
 662         freeaddrinfo(ai0);
 663
 664         if (sockfd < 0)
 665                 die(_("unable to connect to %s:\n%s"), host, error_message.buf);
 666
 667         enable_keepalive(sockfd);
 668
 669         if (flags & CONNECT_VERBOSE)
 670                 /* TRANSLATORS: this is the end of "Connecting to %s (port %s) ... " */
 671                 fprintf_ln(stderr, _("done."));
 672
 673         strbuf_release(&error_message);
 674
 675         return sockfd;
 676 }
 677
 678 #else /* NO_IPV6 */
 679
 680 /*
 681  * Returns a connected socket() fd, or else die()s.
 682  */
 683 static int git_tcp_connect_sock(char *host, int flags)
 684 {
 685         struct strbuf error_message = STRBUF_INIT;
 686         int sockfd = -1;
 687         const char *port = STR(DEFAULT_GIT_PORT);
 688         char *ep;
 689         struct hostent *he;
 690         struct sockaddr_in sa;
 691         char **ap;
 692         unsigned int nport;
 693         int cnt;
 694
 695         get_host_and_port(&host, &port);
 696
 697         if (flags & CONNECT_VERBOSE)
 698                 fprintf(stderr, _("Looking up %s ... "), host);
 699
 700         he = gethostbyname(host);
 701         if (!he)
 702                 die(_("unable to look up %s (%s)"), host, hstrerror(h_errno));
 703         nport = strtoul(port, &ep, 10);
 704         if ( ep == port || *ep ) {
 705                 /* Not numeric */
 706                 struct servent *se = getservbyname(port,"tcp");
 707                 if ( !se )
 708                         die(_("unknown port %s"), port);
 709                 nport = se->s_port;
 710         }
 711
 712         if (flags & CONNECT_VERBOSE)
 713                 /* TRANSLATORS: this is the end of "Looking up %s ... " */
 714                 fprintf(stderr, _("done.\nConnecting to %s (port %s) ... "), host, port);
 715
 716         for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
 717                 memset(&sa, 0, sizeof sa);
 718                 sa.sin_family = he->h_addrtype;
 719                 sa.sin_port = htons(nport);
 720                 memcpy(&sa.sin_addr, *ap, he->h_length);
 721
 722                 sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 723                 if ((sockfd < 0) ||
 724                     connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 725                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 726                                 host,
 727                                 cnt,
 728                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr),
 729                                 strerror(errno));
 730                         if (0 <= sockfd)
 731                                 close(sockfd);
 732                         sockfd = -1;
 733                         continue;
 734                 }
 735                 if (flags & CONNECT_VERBOSE)
 736                         fprintf(stderr, "%s ",
 737                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr));
 738                 break;
 739         }
 740
 741         if (sockfd < 0)
 742                 die(_("unable to connect to %s:\n%s"), host, error_message.buf);
 743
 744         enable_keepalive(sockfd);
 745
 746         if (flags & CONNECT_VERBOSE)
 747                 /* TRANSLATORS: this is the end of "Connecting to %s (port %s) ... " */
 748                 fprintf_ln(stderr, _("done."));
 749
 750         return sockfd;
 751 }
 752
 753 #endif /* NO_IPV6 */
 754
 755
 756 /*
 757  * Dummy child_process returned by git_connect() if the transport protocol
 758  * does not need fork(2).
 759  */
 760 static struct child_process no_fork = CHILD_PROCESS_INIT;
 761
 762 int git_connection_is_socket(struct child_process *conn)
 763 {
 764         return conn == &no_fork;
 765 }
 766
 767 static struct child_process *git_tcp_connect(int fd[2], char *host, int flags)
 768 {
 769         int sockfd = git_tcp_connect_sock(host, flags);
 770
 771         fd[0] = sockfd;
 772         fd[1] = dup(sockfd);
 773
 774         return &no_fork;
 775 }
 776
 777
 778 static char *git_proxy_command;
 779
 780 static int git_proxy_command_options(const char *var, const char *value,
 781                 void *cb)
 782 {
 783         if (!strcmp(var, "core.gitproxy")) {
 784                 const char *for_pos;
 785                 int matchlen = -1;
 786                 int hostlen;
 787                 const char *rhost_name = cb;
 788                 int rhost_len = strlen(rhost_name);
 789
 790                 if (git_proxy_command)
 791                         return 0;
 792                 if (!value)
 793                         return config_error_nonbool(var);
 794                 /* [core]
 795                  * ;# matches www.kernel.org as well
 796                  * gitproxy = netcatter-1 for kernel.org
 797                  * gitproxy = netcatter-2 for sample.xz
 798                  * gitproxy = netcatter-default
 799                  */
 800                 for_pos = strstr(value, " for ");
 801                 if (!for_pos)
 802                         /* matches everybody */
 803                         matchlen = strlen(value);
 804                 else {
 805                         hostlen = strlen(for_pos + 5);
 806                         if (rhost_len < hostlen)
 807                                 matchlen = -1;
 808                         else if (!strncmp(for_pos + 5,
 809                                           rhost_name + rhost_len - hostlen,
 810                                           hostlen) &&
 811                                  ((rhost_len == hostlen) ||
 812                                   rhost_name[rhost_len - hostlen -1] == '.'))
 813                                 matchlen = for_pos - value;
 814                         else
 815                                 matchlen = -1;
 816                 }
 817                 if (0 <= matchlen) {
 818                         /* core.gitproxy = none for kernel.org */
 819                         if (matchlen == 4 &&
 820                             !memcmp(value, "none", 4))
 821                                 matchlen = 0;
 822                         git_proxy_command = xmemdupz(value, matchlen);
 823                 }
 824                 return 0;
 825         }
 826
 827         return git_default_config(var, value, cb);
 828 }
 829
 830 static int git_use_proxy(const char *host)
 831 {
 832         git_proxy_command = getenv("GIT_PROXY_COMMAND");
 833         git_config(git_proxy_command_options, (void*)host);
 834         return (git_proxy_command && *git_proxy_command);
 835 }
 836
 837 static struct child_process *git_proxy_connect(int fd[2], char *host)
 838 {
 839         const char *port = STR(DEFAULT_GIT_PORT);
 840         struct child_process *proxy;
 841
 842         get_host_and_port(&host, &port);
 843
 844         if (looks_like_command_line_option(host))
 845                 die(_("strange hostname '%s' blocked"), host);
 846         if (looks_like_command_line_option(port))
 847                 die(_("strange port '%s' blocked"), port);
 848
 849         proxy = xmalloc(sizeof(*proxy));
 850         child_process_init(proxy);
 851         argv_array_push(&proxy->args, git_proxy_command);
 852         argv_array_push(&proxy->args, host);
 853         argv_array_push(&proxy->args, port);
 854         proxy->in = -1;
 855         proxy->out = -1;
 856         if (start_command(proxy))
 857                 die(_("cannot start proxy %s"), git_proxy_command);
 858         fd[0] = proxy->out; /* read from proxy stdout */
 859         fd[1] = proxy->in;  /* write to proxy stdin */
 860         return proxy;
 861 }
 862
 863 static char *get_port(char *host)
 864 {
 865         char *end;
 866         char *p = strchr(host, ':');
 867
 868         if (p) {
 869                 long port = strtol(p + 1, &end, 10);
 870                 if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
 871                         *p = '\0';
 872                         return p+1;
 873                 }
 874         }
 875
 876         return NULL;
 877 }
 878
 879 /*
 880  * Extract protocol and relevant parts from the specified connection URL.
 881  * The caller must free() the returned strings.
 882  */
 883 static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
 884                                        char **ret_path)
 885 {
 886         char *url;
 887         char *host, *path;
 888         char *end;
 889         int separator = '/';
 890         enum protocol protocol = PROTO_LOCAL;
 891
 892         if (is_url(url_orig))
 893                 url = url_decode(url_orig);
 894         else
 895                 url = xstrdup(url_orig);
 896
 897         host = strstr(url, "://");
 898         if (host) {
 899                 *host = '\0';
 900                 protocol = get_protocol(url);
 901                 host += 3;
 902         } else {
 903                 host = url;
 904                 if (!url_is_local_not_ssh(url)) {
 905                         protocol = PROTO_SSH;
 906                         separator = ':';
 907                 }
 908         }
 909
 910         /*
 911          * Don't do destructive transforms as protocol code does
 912          * '[]' unwrapping in get_host_and_port()
 913          */
 914         end = host_end(&host, 0);
 915
 916         if (protocol == PROTO_LOCAL)
 917                 path = end;
 918         else if (protocol == PROTO_FILE && *host != '/' &&
 919                  !has_dos_drive_prefix(host) &&
 920                  offset_1st_component(host - 2) > 1)
 921                 path = host - 2; /* include the leading "//" */
 922         else if (protocol == PROTO_FILE && has_dos_drive_prefix(end))
 923                 path = end; /* "file://$(pwd)" may be "file://C:/projects/repo" */
 924         else
 925                 path = strchr(end, separator);
 926
 927         if (!path || !*path)
 928                 die(_("no path specified; see 'git help pull' for valid url syntax"));
 929
 930         /*
 931          * null-terminate hostname and point path to ~ for URL's like this:
 932          *    ssh://host.xz/~user/repo
 933          */
 934
 935         end = path; /* Need to \0 terminate host here */
 936         if (separator == ':')
 937                 path++; /* path starts after ':' */
 938         if (protocol == PROTO_GIT || protocol == PROTO_SSH) {
 939                 if (path[1] == '~')
 940                         path++;
 941         }
 942
 943         path = xstrdup(path);
 944         *end = '\0';
 945
 946         *ret_host = xstrdup(host);
 947         *ret_path = path;
 948         free(url);
 949         return protocol;
 950 }
 951
 952 static const char *get_ssh_command(void)
 953 {
 954         const char *ssh;
 955
 956         if ((ssh = getenv("GIT_SSH_COMMAND")))
 957                 return ssh;
 958
 959         if (!git_config_get_string_const("core.sshcommand", &ssh))
 960                 return ssh;
 961
 962         return NULL;
 963 }
 964
 965 enum ssh_variant {
 966         VARIANT_AUTO,
 967         VARIANT_SIMPLE,
 968         VARIANT_SSH,
 969         VARIANT_PLINK,
 970         VARIANT_PUTTY,
 971         VARIANT_TORTOISEPLINK,
 972 };
 973
 974 static void override_ssh_variant(enum ssh_variant *ssh_variant)
 975 {
 976         const char *variant = getenv("GIT_SSH_VARIANT");
 977
 978         if (!variant && git_config_get_string_const("ssh.variant", &variant))
 979                 return;
 980
 981         if (!strcmp(variant, "auto"))
 982                 *ssh_variant = VARIANT_AUTO;
 983         else if (!strcmp(variant, "plink"))
 984                 *ssh_variant = VARIANT_PLINK;
 985         else if (!strcmp(variant, "putty"))
 986                 *ssh_variant = VARIANT_PUTTY;
 987         else if (!strcmp(variant, "tortoiseplink"))
 988                 *ssh_variant = VARIANT_TORTOISEPLINK;
 989         else if (!strcmp(variant, "simple"))
 990                 *ssh_variant = VARIANT_SIMPLE;
 991         else
 992                 *ssh_variant = VARIANT_SSH;
 993 }
 994
 995 static enum ssh_variant determine_ssh_variant(const char *ssh_command,
 996                                               int is_cmdline)
 997 {
 998         enum ssh_variant ssh_variant = VARIANT_AUTO;
 999         const char *variant;
1000         char *p = NULL;
1001
1002         override_ssh_variant(&ssh_variant);
1003
1004         if (ssh_variant != VARIANT_AUTO)
1005                 return ssh_variant;
1006
1007         if (!is_cmdline) {
1008                 p = xstrdup(ssh_command);
1009                 variant = basename(p);
1010         } else {
1011                 const char **ssh_argv;
1012
1013                 p = xstrdup(ssh_command);
1014                 if (split_cmdline(p, &ssh_argv) > 0) {
1015                         variant = basename((char *)ssh_argv[0]);
1016                         /*
1017                          * At this point, variant points into the buffer
1018                          * referenced by p, hence we do not need ssh_argv
1019                          * any longer.
1020                          */
1021                         free(ssh_argv);
1022                 } else {
1023                         free(p);
1024                         return ssh_variant;
1025                 }
1026         }
1027
1028         if (!strcasecmp(variant, "ssh") ||
1029             !strcasecmp(variant, "ssh.exe"))
1030                 ssh_variant = VARIANT_SSH;
1031         else if (!strcasecmp(variant, "plink") ||
1032                  !strcasecmp(variant, "plink.exe"))
1033                 ssh_variant = VARIANT_PLINK;
1034         else if (!strcasecmp(variant, "tortoiseplink") ||
1035                  !strcasecmp(variant, "tortoiseplink.exe"))
1036                 ssh_variant = VARIANT_TORTOISEPLINK;
1037
1038         free(p);
1039         return ssh_variant;
1040 }
1041
1042 /*
1043  * Open a connection using Git's native protocol.
1044  *
1045  * The caller is responsible for freeing hostandport, but this function may
1046  * modify it (for example, to truncate it to remove the port part).
1047  */
1048 static struct child_process *git_connect_git(int fd[2], char *hostandport,
1049                                              const char *path, const char *prog,
1050                                              enum protocol_version version,
1051                                              int flags)
1052 {
1053         struct child_process *conn;
1054         struct strbuf request = STRBUF_INIT;
1055         /*
1056          * Set up virtual host information based on where we will
1057          * connect, unless the user has overridden us in
1058          * the environment.
1059          */
1060         char *target_host = getenv("GIT_OVERRIDE_VIRTUAL_HOST");
1061         if (target_host)
1062                 target_host = xstrdup(target_host);
1063         else
1064                 target_host = xstrdup(hostandport);
1065
1066         transport_check_allowed("git");
1067
1068         /*
1069          * These underlying connection commands die() if they
1070          * cannot connect.
1071          */
1072         if (git_use_proxy(hostandport))
1073                 conn = git_proxy_connect(fd, hostandport);
1074         else
1075                 conn = git_tcp_connect(fd, hostandport, flags);
1076         /*
1077          * Separate original protocol components prog and path
1078          * from extended host header with a NUL byte.
1079          *
1080          * Note: Do not add any other headers here!  Doing so
1081          * will cause older git-daemon servers to crash.
1082          */
1083         strbuf_addf(&request,
1084                     "%s %s%chost=%s%c",
1085                     prog, path, 0,
1086                     target_host, 0);
1087
1088         /* If using a new version put that stuff here after a second null byte */
1089         if (version > 0) {
1090                 strbuf_addch(&request, '\0');
1091                 strbuf_addf(&request, "version=%d%c",
1092                             version, '\0');
1093         }
1094
1095         packet_write(fd[1], request.buf, request.len);
1096
1097         free(target_host);
1098         strbuf_release(&request);
1099         return conn;
1100 }
1101
1102 /*
1103  * Append the appropriate environment variables to `env` and options to
1104  * `args` for running ssh in Git's SSH-tunneled transport.
1105  */
1106 static void push_ssh_options(struct argv_array *args, struct argv_array *env,
1107                              enum ssh_variant variant, const char *port,
1108                              enum protocol_version version, int flags)
1109 {
1110         if (variant == VARIANT_SSH &&
1111             version > 0) {
1112                 argv_array_push(args, "-o");
1113                 argv_array_push(args, "SendEnv=" GIT_PROTOCOL_ENVIRONMENT);
1114                 argv_array_pushf(env, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
1115                                  version);
1116         }
1117
1118         if (flags & CONNECT_IPV4) {
1119                 switch (variant) {
1120                 case VARIANT_AUTO:
1121                         BUG("VARIANT_AUTO passed to push_ssh_options");
1122                 case VARIANT_SIMPLE:
1123                         die(_("ssh variant 'simple' does not support -4"));
1124                 case VARIANT_SSH:
1125                 case VARIANT_PLINK:
1126                 case VARIANT_PUTTY:
1127                 case VARIANT_TORTOISEPLINK:
1128                         argv_array_push(args, "-4");
1129                 }
1130         } else if (flags & CONNECT_IPV6) {
1131                 switch (variant) {
1132                 case VARIANT_AUTO:
1133                         BUG("VARIANT_AUTO passed to push_ssh_options");
1134                 case VARIANT_SIMPLE:
1135                         die(_("ssh variant 'simple' does not support -6"));
1136                 case VARIANT_SSH:
1137                 case VARIANT_PLINK:
1138                 case VARIANT_PUTTY:
1139                 case VARIANT_TORTOISEPLINK:
1140                         argv_array_push(args, "-6");
1141                 }
1142         }
1143
1144         if (variant == VARIANT_TORTOISEPLINK)
1145                 argv_array_push(args, "-batch");
1146
1147         if (port) {
1148                 switch (variant) {
1149                 case VARIANT_AUTO:
1150                         BUG("VARIANT_AUTO passed to push_ssh_options");
1151                 case VARIANT_SIMPLE:
1152                         die(_("ssh variant 'simple' does not support setting port"));
1153                 case VARIANT_SSH:
1154                         argv_array_push(args, "-p");
1155                         break;
1156                 case VARIANT_PLINK:
1157                 case VARIANT_PUTTY:
1158                 case VARIANT_TORTOISEPLINK:
1159                         argv_array_push(args, "-P");
1160                 }
1161
1162                 argv_array_push(args, port);
1163         }
1164 }
1165
1166 /* Prepare a child_process for use by Git's SSH-tunneled transport. */
1167 static void fill_ssh_args(struct child_process *conn, const char *ssh_host,
1168                           const char *port, enum protocol_version version,
1169                           int flags)
1170 {
1171         const char *ssh;
1172         enum ssh_variant variant;
1173
1174         if (looks_like_command_line_option(ssh_host))
1175                 die(_("strange hostname '%s' blocked"), ssh_host);
1176
1177         ssh = get_ssh_command();
1178         if (ssh) {
1179                 variant = determine_ssh_variant(ssh, 1);
1180         } else {
1181                 /*
1182                  * GIT_SSH is the no-shell version of
1183                  * GIT_SSH_COMMAND (and must remain so for
1184                  * historical compatibility).
1185                  */
1186                 conn->use_shell = 0;
1187
1188                 ssh = getenv("GIT_SSH");
1189                 if (!ssh)
1190                         ssh = "ssh";
1191                 variant = determine_ssh_variant(ssh, 0);
1192         }
1193
1194         if (variant == VARIANT_AUTO) {
1195                 struct child_process detect = CHILD_PROCESS_INIT;
1196
1197                 detect.use_shell = conn->use_shell;
1198                 detect.no_stdin = detect.no_stdout = detect.no_stderr = 1;
1199
1200                 argv_array_push(&detect.args, ssh);
1201                 argv_array_push(&detect.args, "-G");
1202                 push_ssh_options(&detect.args, &detect.env_array,
1203                                  VARIANT_SSH, port, version, flags);
1204                 argv_array_push(&detect.args, ssh_host);
1205
1206                 variant = run_command(&detect) ? VARIANT_SIMPLE : VARIANT_SSH;
1207         }
1208
1209         argv_array_push(&conn->args, ssh);
1210         push_ssh_options(&conn->args, &conn->env_array, variant, port, version, flags);
1211         argv_array_push(&conn->args, ssh_host);
1212 }
1213
1214 /*
1215  * This returns the dummy child_process `no_fork` if the transport protocol
1216  * does not need fork(2), or a struct child_process object if it does.  Once
1217  * done, finish the connection with finish_connect() with the value returned
1218  * from this function (it is safe to call finish_connect() with NULL to
1219  * support the former case).
1220  *
1221  * If it returns, the connect is successful; it just dies on errors (this
1222  * will hopefully be changed in a libification effort, to return NULL when
1223  * the connection failed).
1224  */
1225 struct child_process *git_connect(int fd[2], const char *url,
1226                                   const char *prog, int flags)
1227 {
1228         char *hostandport, *path;
1229         struct child_process *conn;
1230         enum protocol protocol;
1231         enum protocol_version version = get_protocol_version_config();
1232
1233         /*
1234          * NEEDSWORK: If we are trying to use protocol v2 and we are planning
1235          * to perform a push, then fallback to v0 since the client doesn't know
1236          * how to push yet using v2.
1237          */
1238         if (version == protocol_v2 && !strcmp("git-receive-pack", prog))
1239                 version = protocol_v0;
1240
1241         /* Without this we cannot rely on waitpid() to tell
1242          * what happened to our children.
1243          */
1244         signal(SIGCHLD, SIG_DFL);
1245
1246         protocol = parse_connect_url(url, &hostandport, &path);
1247         if ((flags & CONNECT_DIAG_URL) && (protocol != PROTO_SSH)) {
1248                 printf("Diag: url=%s\n", url ? url : "NULL");
1249                 printf("Diag: protocol=%s\n", prot_name(protocol));
1250                 printf("Diag: hostandport=%s\n", hostandport ? hostandport : "NULL");
1251                 printf("Diag: path=%s\n", path ? path : "NULL");
1252                 conn = NULL;
1253         } else if (protocol == PROTO_GIT) {
1254                 conn = git_connect_git(fd, hostandport, path, prog, version, flags);
1255                 conn->trace2_child_class = "transport/git";
1256         } else {
1257                 struct strbuf cmd = STRBUF_INIT;
1258                 const char *const *var;
1259
1260                 conn = xmalloc(sizeof(*conn));
1261                 child_process_init(conn);
1262
1263                 if (looks_like_command_line_option(path))
1264                         die(_("strange pathname '%s' blocked"), path);
1265
1266                 strbuf_addstr(&cmd, prog);
1267                 strbuf_addch(&cmd, ' ');
1268                 sq_quote_buf(&cmd, path);
1269
1270                 /* remove repo-local variables from the environment */
1271                 for (var = local_repo_env; *var; var++)
1272                         argv_array_push(&conn->env_array, *var);
1273
1274                 conn->use_shell = 1;
1275                 conn->in = conn->out = -1;
1276                 if (protocol == PROTO_SSH) {
1277                         char *ssh_host = hostandport;
1278                         const char *port = NULL;
1279                         transport_check_allowed("ssh");
1280                         get_host_and_port(&ssh_host, &port);
1281
1282                         if (!port)
1283                                 port = get_port(ssh_host);
1284
1285                         if (flags & CONNECT_DIAG_URL) {
1286                                 printf("Diag: url=%s\n", url ? url : "NULL");
1287                                 printf("Diag: protocol=%s\n", prot_name(protocol));
1288                                 printf("Diag: userandhost=%s\n", ssh_host ? ssh_host : "NULL");
1289                                 printf("Diag: port=%s\n", port ? port : "NONE");
1290                                 printf("Diag: path=%s\n", path ? path : "NULL");
1291
1292                                 free(hostandport);
1293                                 free(path);
1294                                 free(conn);
1295                                 strbuf_release(&cmd);
1296                                 return NULL;
1297                         }
1298                         conn->trace2_child_class = "transport/ssh";
1299                         fill_ssh_args(conn, ssh_host, port, version, flags);
1300                 } else {
1301                         transport_check_allowed("file");
1302                         conn->trace2_child_class = "transport/file";
1303                         if (version > 0) {
1304                                 argv_array_pushf(&conn->env_array, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
1305                                                  version);
1306                         }
1307                 }
1308                 argv_array_push(&conn->args, cmd.buf);
1309
1310                 if (start_command(conn))
1311                         die(_("unable to fork"));
1312
1313                 fd[0] = conn->out; /* read from child's stdout */
1314                 fd[1] = conn->in;  /* write to child's stdin */
1315                 strbuf_release(&cmd);
1316         }
1317         free(hostandport);
1318         free(path);
1319         return conn;
1320 }
1321
1322 int finish_connect(struct child_process *conn)
1323 {
1324         int code;
1325         if (!conn || git_connection_is_socket(conn))
1326                 return 0;
1327
1328         code = finish_command(conn);
1329         free(conn);
1330         return code;
1331 }