connect.c

   1 #include "git-compat-util.h"
   2 #include "cache.h"
   3 #include "config.h"
   4 #include "hex.h"
   5 #include "pkt-line.h"
   6 #include "quote.h"
   7 #include "refs.h"
   8 #include "run-command.h"
   9 #include "remote.h"
  10 #include "connect.h"
  11 #include "url.h"
  12 #include "string-list.h"
  13 #include "oid-array.h"
  14 #include "transport.h"
  15 #include "strbuf.h"
  16 #include "version.h"
  17 #include "protocol.h"
  18 #include "alias.h"
  19 #include "bundle-uri.h"
  20
  21 static char *server_capabilities_v1;
  22 static struct strvec server_capabilities_v2 = STRVEC_INIT;
  23 static const char *next_server_feature_value(const char *feature, int *len, int *offset);
  24
  25 static int check_ref(const char *name, unsigned int flags)
  26 {
  27         if (!flags)
  28                 return 1;
  29
  30         if (!skip_prefix(name, "refs/", &name))
  31                 return 0;
  32
  33         /* REF_NORMAL means that we don't want the magic fake tag refs */
  34         if ((flags & REF_NORMAL) && check_refname_format(name, 0))
  35                 return 0;
  36
  37         /* REF_HEADS means that we want regular branch heads */
  38         if ((flags & REF_HEADS) && starts_with(name, "heads/"))
  39                 return 1;
  40
  41         /* REF_TAGS means that we want tags */
  42         if ((flags & REF_TAGS) && starts_with(name, "tags/"))
  43                 return 1;
  44
  45         /* All type bits clear means that we are ok with anything */
  46         return !(flags & ~REF_NORMAL);
  47 }
  48
  49 int check_ref_type(const struct ref *ref, int flags)
  50 {
  51         return check_ref(ref->name, flags);
  52 }
  53
  54 static NORETURN void die_initial_contact(int unexpected)
  55 {
  56         /*
  57          * A hang-up after seeing some response from the other end
  58          * means that it is unexpected, as we know the other end is
  59          * willing to talk to us.  A hang-up before seeing any
  60          * response does not necessarily mean an ACL problem, though.
  61          */
  62         if (unexpected)
  63                 die(_("the remote end hung up upon initial contact"));
  64         else
  65                 die(_("Could not read from remote repository.\n\n"
  66                       "Please make sure you have the correct access rights\n"
  67                       "and the repository exists."));
  68 }
  69
  70 /* Checks if the server supports the capability 'c' */
  71 int server_supports_v2(const char *c)
  72 {
  73         int i;
  74
  75         for (i = 0; i < server_capabilities_v2.nr; i++) {
  76                 const char *out;
  77                 if (skip_prefix(server_capabilities_v2.v[i], c, &out) &&
  78                     (!*out || *out == '='))
  79                         return 1;
  80         }
  81         return 0;
  82 }
  83
  84 void ensure_server_supports_v2(const char *c)
  85 {
  86         if (!server_supports_v2(c))
  87                 die(_("server doesn't support '%s'"), c);
  88 }
  89
  90 int server_feature_v2(const char *c, const char **v)
  91 {
  92         int i;
  93
  94         for (i = 0; i < server_capabilities_v2.nr; i++) {
  95                 const char *out;
  96                 if (skip_prefix(server_capabilities_v2.v[i], c, &out) &&
  97                     (*out == '=')) {
  98                         *v = out + 1;
  99                         return 1;
 100                 }
 101         }
 102         return 0;
 103 }
 104
 105 int server_supports_feature(const char *c, const char *feature,
 106                             int die_on_error)
 107 {
 108         int i;
 109
 110         for (i = 0; i < server_capabilities_v2.nr; i++) {
 111                 const char *out;
 112                 if (skip_prefix(server_capabilities_v2.v[i], c, &out) &&
 113                     (!*out || *(out++) == '=')) {
 114                         if (parse_feature_request(out, feature))
 115                                 return 1;
 116                         else
 117                                 break;
 118                 }
 119         }
 120
 121         if (die_on_error)
 122                 die(_("server doesn't support feature '%s'"), feature);
 123
 124         return 0;
 125 }
 126
 127 static void process_capabilities_v2(struct packet_reader *reader)
 128 {
 129         while (packet_reader_read(reader) == PACKET_READ_NORMAL)
 130                 strvec_push(&server_capabilities_v2, reader->line);
 131
 132         if (reader->status != PACKET_READ_FLUSH)
 133                 die(_("expected flush after capabilities"));
 134 }
 135
 136 enum protocol_version discover_version(struct packet_reader *reader)
 137 {
 138         enum protocol_version version = protocol_unknown_version;
 139
 140         /*
 141          * Peek the first line of the server's response to
 142          * determine the protocol version the server is speaking.
 143          */
 144         switch (packet_reader_peek(reader)) {
 145         case PACKET_READ_EOF:
 146                 die_initial_contact(0);
 147         case PACKET_READ_FLUSH:
 148         case PACKET_READ_DELIM:
 149         case PACKET_READ_RESPONSE_END:
 150                 version = protocol_v0;
 151                 break;
 152         case PACKET_READ_NORMAL:
 153                 version = determine_protocol_version_client(reader->line);
 154                 break;
 155         }
 156
 157         switch (version) {
 158         case protocol_v2:
 159                 process_capabilities_v2(reader);
 160                 break;
 161         case protocol_v1:
 162                 /* Read the peeked version line */
 163                 packet_reader_read(reader);
 164                 break;
 165         case protocol_v0:
 166                 break;
 167         case protocol_unknown_version:
 168                 BUG("unknown protocol version");
 169         }
 170
 171         trace2_data_intmax("transfer", NULL, "negotiated-version", version);
 172
 173         return version;
 174 }
 175
 176 static void parse_one_symref_info(struct string_list *symref, const char *val, int len)
 177 {
 178         char *sym, *target;
 179         struct string_list_item *item;
 180
 181         if (!len)
 182                 return; /* just "symref" */
 183         /* e.g. "symref=HEAD:refs/heads/master" */
 184         sym = xmemdupz(val, len);
 185         target = strchr(sym, ':');
 186         if (!target)
 187                 /* just "symref=something" */
 188                 goto reject;
 189         *(target++) = '\0';
 190         if (check_refname_format(sym, REFNAME_ALLOW_ONELEVEL) ||
 191             check_refname_format(target, REFNAME_ALLOW_ONELEVEL))
 192                 /* "symref=bogus:pair */
 193                 goto reject;
 194         item = string_list_append_nodup(symref, sym);
 195         item->util = target;
 196         return;
 197 reject:
 198         free(sym);
 199         return;
 200 }
 201
 202 static void annotate_refs_with_symref_info(struct ref *ref)
 203 {
 204         struct string_list symref = STRING_LIST_INIT_DUP;
 205         int offset = 0;
 206
 207         while (1) {
 208                 int len;
 209                 const char *val;
 210
 211                 val = next_server_feature_value("symref", &len, &offset);
 212                 if (!val)
 213                         break;
 214                 parse_one_symref_info(&symref, val, len);
 215         }
 216         string_list_sort(&symref);
 217
 218         for (; ref; ref = ref->next) {
 219                 struct string_list_item *item;
 220                 item = string_list_lookup(&symref, ref->name);
 221                 if (!item)
 222                         continue;
 223                 ref->symref = xstrdup((char *)item->util);
 224         }
 225         string_list_clear(&symref, 0);
 226 }
 227
 228 static void process_capabilities(struct packet_reader *reader, int *linelen)
 229 {
 230         const char *feat_val;
 231         int feat_len;
 232         const char *line = reader->line;
 233         int nul_location = strlen(line);
 234         if (nul_location == *linelen)
 235                 return;
 236         server_capabilities_v1 = xstrdup(line + nul_location + 1);
 237         *linelen = nul_location;
 238
 239         feat_val = server_feature_value("object-format", &feat_len);
 240         if (feat_val) {
 241                 char *hash_name = xstrndup(feat_val, feat_len);
 242                 int hash_algo = hash_algo_by_name(hash_name);
 243                 if (hash_algo != GIT_HASH_UNKNOWN)
 244                         reader->hash_algo = &hash_algos[hash_algo];
 245                 free(hash_name);
 246         } else {
 247                 reader->hash_algo = &hash_algos[GIT_HASH_SHA1];
 248         }
 249 }
 250
 251 static int process_dummy_ref(const struct packet_reader *reader)
 252 {
 253         const char *line = reader->line;
 254         struct object_id oid;
 255         const char *name;
 256
 257         if (parse_oid_hex_algop(line, &oid, &name, reader->hash_algo))
 258                 return 0;
 259         if (*name != ' ')
 260                 return 0;
 261         name++;
 262
 263         return oideq(null_oid(), &oid) && !strcmp(name, "capabilities^{}");
 264 }
 265
 266 static void check_no_capabilities(const char *line, int len)
 267 {
 268         if (strlen(line) != len)
 269                 warning(_("ignoring capabilities after first line '%s'"),
 270                         line + strlen(line));
 271 }
 272
 273 static int process_ref(const struct packet_reader *reader, int len,
 274                        struct ref ***list, unsigned int flags,
 275                        struct oid_array *extra_have)
 276 {
 277         const char *line = reader->line;
 278         struct object_id old_oid;
 279         const char *name;
 280
 281         if (parse_oid_hex_algop(line, &old_oid, &name, reader->hash_algo))
 282                 return 0;
 283         if (*name != ' ')
 284                 return 0;
 285         name++;
 286
 287         if (extra_have && !strcmp(name, ".have")) {
 288                 oid_array_append(extra_have, &old_oid);
 289         } else if (!strcmp(name, "capabilities^{}")) {
 290                 die(_("protocol error: unexpected capabilities^{}"));
 291         } else if (check_ref(name, flags)) {
 292                 struct ref *ref = alloc_ref(name);
 293                 oidcpy(&ref->old_oid, &old_oid);
 294                 **list = ref;
 295                 *list = &ref->next;
 296         }
 297         check_no_capabilities(line, len);
 298         return 1;
 299 }
 300
 301 static int process_shallow(const struct packet_reader *reader, int len,
 302                            struct oid_array *shallow_points)
 303 {
 304         const char *line = reader->line;
 305         const char *arg;
 306         struct object_id old_oid;
 307
 308         if (!skip_prefix(line, "shallow ", &arg))
 309                 return 0;
 310
 311         if (get_oid_hex_algop(arg, &old_oid, reader->hash_algo))
 312                 die(_("protocol error: expected shallow sha-1, got '%s'"), arg);
 313         if (!shallow_points)
 314                 die(_("repository on the other end cannot be shallow"));
 315         oid_array_append(shallow_points, &old_oid);
 316         check_no_capabilities(line, len);
 317         return 1;
 318 }
 319
 320 enum get_remote_heads_state {
 321         EXPECTING_FIRST_REF = 0,
 322         EXPECTING_REF,
 323         EXPECTING_SHALLOW,
 324         EXPECTING_DONE,
 325 };
 326
 327 /*
 328  * Read all the refs from the other end
 329  */
 330 struct ref **get_remote_heads(struct packet_reader *reader,
 331                               struct ref **list, unsigned int flags,
 332                               struct oid_array *extra_have,
 333                               struct oid_array *shallow_points)
 334 {
 335         struct ref **orig_list = list;
 336         int len = 0;
 337         enum get_remote_heads_state state = EXPECTING_FIRST_REF;
 338
 339         *list = NULL;
 340
 341         while (state != EXPECTING_DONE) {
 342                 switch (packet_reader_read(reader)) {
 343                 case PACKET_READ_EOF:
 344                         die_initial_contact(1);
 345                 case PACKET_READ_NORMAL:
 346                         len = reader->pktlen;
 347                         break;
 348                 case PACKET_READ_FLUSH:
 349                         state = EXPECTING_DONE;
 350                         break;
 351                 case PACKET_READ_DELIM:
 352                 case PACKET_READ_RESPONSE_END:
 353                         die(_("invalid packet"));
 354                 }
 355
 356                 switch (state) {
 357                 case EXPECTING_FIRST_REF:
 358                         process_capabilities(reader, &len);
 359                         if (process_dummy_ref(reader)) {
 360                                 state = EXPECTING_SHALLOW;
 361                                 break;
 362                         }
 363                         state = EXPECTING_REF;
 364                         /* fallthrough */
 365                 case EXPECTING_REF:
 366                         if (process_ref(reader, len, &list, flags, extra_have))
 367                                 break;
 368                         state = EXPECTING_SHALLOW;
 369                         /* fallthrough */
 370                 case EXPECTING_SHALLOW:
 371                         if (process_shallow(reader, len, shallow_points))
 372                                 break;
 373                         die(_("protocol error: unexpected '%s'"), reader->line);
 374                 case EXPECTING_DONE:
 375                         break;
 376                 }
 377         }
 378
 379         annotate_refs_with_symref_info(*orig_list);
 380
 381         return list;
 382 }
 383
 384 /* Returns 1 when a valid ref has been added to `list`, 0 otherwise */
 385 static int process_ref_v2(struct packet_reader *reader, struct ref ***list,
 386                           const char **unborn_head_target)
 387 {
 388         int ret = 1;
 389         int i = 0;
 390         struct object_id old_oid;
 391         struct ref *ref;
 392         struct string_list line_sections = STRING_LIST_INIT_DUP;
 393         const char *end;
 394         const char *line = reader->line;
 395
 396         /*
 397          * Ref lines have a number of fields which are space deliminated.  The
 398          * first field is the OID of the ref.  The second field is the ref
 399          * name.  Subsequent fields (symref-target and peeled) are optional and
 400          * don't have a particular order.
 401          */
 402         if (string_list_split(&line_sections, line, ' ', -1) < 2) {
 403                 ret = 0;
 404                 goto out;
 405         }
 406
 407         if (!strcmp("unborn", line_sections.items[i].string)) {
 408                 i++;
 409                 if (unborn_head_target &&
 410                     !strcmp("HEAD", line_sections.items[i++].string)) {
 411                         /*
 412                          * Look for the symref target (if any). If found,
 413                          * return it to the caller.
 414                          */
 415                         for (; i < line_sections.nr; i++) {
 416                                 const char *arg = line_sections.items[i].string;
 417
 418                                 if (skip_prefix(arg, "symref-target:", &arg)) {
 419                                         *unborn_head_target = xstrdup(arg);
 420                                         break;
 421                                 }
 422                         }
 423                 }
 424                 goto out;
 425         }
 426         if (parse_oid_hex_algop(line_sections.items[i++].string, &old_oid, &end, reader->hash_algo) ||
 427             *end) {
 428                 ret = 0;
 429                 goto out;
 430         }
 431
 432         ref = alloc_ref(line_sections.items[i++].string);
 433
 434         memcpy(ref->old_oid.hash, old_oid.hash, reader->hash_algo->rawsz);
 435         **list = ref;
 436         *list = &ref->next;
 437
 438         for (; i < line_sections.nr; i++) {
 439                 const char *arg = line_sections.items[i].string;
 440                 if (skip_prefix(arg, "symref-target:", &arg))
 441                         ref->symref = xstrdup(arg);
 442
 443                 if (skip_prefix(arg, "peeled:", &arg)) {
 444                         struct object_id peeled_oid;
 445                         char *peeled_name;
 446                         struct ref *peeled;
 447                         if (parse_oid_hex_algop(arg, &peeled_oid, &end,
 448                                                 reader->hash_algo) || *end) {
 449                                 ret = 0;
 450                                 goto out;
 451                         }
 452
 453                         peeled_name = xstrfmt("%s^{}", ref->name);
 454                         peeled = alloc_ref(peeled_name);
 455
 456                         memcpy(peeled->old_oid.hash, peeled_oid.hash,
 457                                reader->hash_algo->rawsz);
 458                         **list = peeled;
 459                         *list = &peeled->next;
 460
 461                         free(peeled_name);
 462                 }
 463         }
 464
 465 out:
 466         string_list_clear(&line_sections, 0);
 467         return ret;
 468 }
 469
 470 void check_stateless_delimiter(int stateless_rpc,
 471                               struct packet_reader *reader,
 472                               const char *error)
 473 {
 474         if (!stateless_rpc)
 475                 return; /* not in stateless mode, no delimiter expected */
 476         if (packet_reader_read(reader) != PACKET_READ_RESPONSE_END)
 477                 die("%s", error);
 478 }
 479
 480 static void send_capabilities(int fd_out, struct packet_reader *reader)
 481 {
 482         const char *hash_name;
 483
 484         if (server_supports_v2("agent"))
 485                 packet_write_fmt(fd_out, "agent=%s", git_user_agent_sanitized());
 486
 487         if (server_feature_v2("object-format", &hash_name)) {
 488                 int hash_algo = hash_algo_by_name(hash_name);
 489                 if (hash_algo == GIT_HASH_UNKNOWN)
 490                         die(_("unknown object format '%s' specified by server"), hash_name);
 491                 reader->hash_algo = &hash_algos[hash_algo];
 492                 packet_write_fmt(fd_out, "object-format=%s", reader->hash_algo->name);
 493         } else {
 494                 reader->hash_algo = &hash_algos[GIT_HASH_SHA1];
 495         }
 496 }
 497
 498 int get_remote_bundle_uri(int fd_out, struct packet_reader *reader,
 499                           struct bundle_list *bundles, int stateless_rpc)
 500 {
 501         int line_nr = 1;
 502
 503         /* Assert bundle-uri support */
 504         ensure_server_supports_v2("bundle-uri");
 505
 506         /* (Re-)send capabilities */
 507         send_capabilities(fd_out, reader);
 508
 509         /* Send command */
 510         packet_write_fmt(fd_out, "command=bundle-uri\n");
 511         packet_delim(fd_out);
 512
 513         packet_flush(fd_out);
 514
 515         /* Process response from server */
 516         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
 517                 const char *line = reader->line;
 518                 line_nr++;
 519
 520                 if (!bundle_uri_parse_line(bundles, line))
 521                         continue;
 522
 523                 return error(_("error on bundle-uri response line %d: %s"),
 524                              line_nr, line);
 525         }
 526
 527         if (reader->status != PACKET_READ_FLUSH)
 528                 return error(_("expected flush after bundle-uri listing"));
 529
 530         /*
 531          * Might die(), but obscure enough that that's OK, e.g. in
 532          * serve.c we'll call BUG() on its equivalent (the
 533          * PACKET_READ_RESPONSE_END check).
 534          */
 535         check_stateless_delimiter(stateless_rpc, reader,
 536                                   _("expected response end packet after ref listing"));
 537
 538         return 0;
 539 }
 540
 541 struct ref **get_remote_refs(int fd_out, struct packet_reader *reader,
 542                              struct ref **list, int for_push,
 543                              struct transport_ls_refs_options *transport_options,
 544                              const struct string_list *server_options,
 545                              int stateless_rpc)
 546 {
 547         int i;
 548         struct strvec *ref_prefixes = transport_options ?
 549                 &transport_options->ref_prefixes : NULL;
 550         const char **unborn_head_target = transport_options ?
 551                 &transport_options->unborn_head_target : NULL;
 552         *list = NULL;
 553
 554         ensure_server_supports_v2("ls-refs");
 555         packet_write_fmt(fd_out, "command=ls-refs\n");
 556
 557         /* Send capabilities */
 558         send_capabilities(fd_out, reader);
 559
 560         if (server_options && server_options->nr) {
 561                 ensure_server_supports_v2("server-option");
 562                 for (i = 0; i < server_options->nr; i++)
 563                         packet_write_fmt(fd_out, "server-option=%s",
 564                                          server_options->items[i].string);
 565         }
 566
 567         packet_delim(fd_out);
 568         /* When pushing we don't want to request the peeled tags */
 569         if (!for_push)
 570                 packet_write_fmt(fd_out, "peel\n");
 571         packet_write_fmt(fd_out, "symrefs\n");
 572         if (server_supports_feature("ls-refs", "unborn", 0))
 573                 packet_write_fmt(fd_out, "unborn\n");
 574         for (i = 0; ref_prefixes && i < ref_prefixes->nr; i++) {
 575                 packet_write_fmt(fd_out, "ref-prefix %s\n",
 576                                  ref_prefixes->v[i]);
 577         }
 578         packet_flush(fd_out);
 579
 580         /* Process response from server */
 581         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
 582                 if (!process_ref_v2(reader, &list, unborn_head_target))
 583                         die(_("invalid ls-refs response: %s"), reader->line);
 584         }
 585
 586         if (reader->status != PACKET_READ_FLUSH)
 587                 die(_("expected flush after ref listing"));
 588
 589         check_stateless_delimiter(stateless_rpc, reader,
 590                                   _("expected response end packet after ref listing"));
 591
 592         return list;
 593 }
 594
 595 const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp, int *offset)
 596 {
 597         int len;
 598
 599         if (!feature_list)
 600                 return NULL;
 601
 602         len = strlen(feature);
 603         if (offset)
 604                 feature_list += *offset;
 605         while (*feature_list) {
 606                 const char *found = strstr(feature_list, feature);
 607                 if (!found)
 608                         return NULL;
 609                 if (feature_list == found || isspace(found[-1])) {
 610                         const char *value = found + len;
 611                         /* feature with no value (e.g., "thin-pack") */
 612                         if (!*value || isspace(*value)) {
 613                                 if (lenp)
 614                                         *lenp = 0;
 615                                 if (offset)
 616                                         *offset = found + len - feature_list;
 617                                 return value;
 618                         }
 619                         /* feature with a value (e.g., "agent=git/1.2.3") */
 620                         else if (*value == '=') {
 621                                 int end;
 622
 623                                 value++;
 624                                 end = strcspn(value, " \t\n");
 625                                 if (lenp)
 626                                         *lenp = end;
 627                                 if (offset)
 628                                         *offset = value + end - feature_list;
 629                                 return value;
 630                         }
 631                         /*
 632                          * otherwise we matched a substring of another feature;
 633                          * keep looking
 634                          */
 635                 }
 636                 feature_list = found + 1;
 637         }
 638         return NULL;
 639 }
 640
 641 int server_supports_hash(const char *desired, int *feature_supported)
 642 {
 643         int offset = 0;
 644         int len;
 645         const char *hash;
 646
 647         hash = next_server_feature_value("object-format", &len, &offset);
 648         if (feature_supported)
 649                 *feature_supported = !!hash;
 650         if (!hash) {
 651                 hash = hash_algos[GIT_HASH_SHA1].name;
 652                 len = strlen(hash);
 653         }
 654         while (hash) {
 655                 if (!xstrncmpz(desired, hash, len))
 656                         return 1;
 657
 658                 hash = next_server_feature_value("object-format", &len, &offset);
 659         }
 660         return 0;
 661 }
 662
 663 int parse_feature_request(const char *feature_list, const char *feature)
 664 {
 665         return !!parse_feature_value(feature_list, feature, NULL, NULL);
 666 }
 667
 668 static const char *next_server_feature_value(const char *feature, int *len, int *offset)
 669 {
 670         return parse_feature_value(server_capabilities_v1, feature, len, offset);
 671 }
 672
 673 const char *server_feature_value(const char *feature, int *len)
 674 {
 675         return parse_feature_value(server_capabilities_v1, feature, len, NULL);
 676 }
 677
 678 int server_supports(const char *feature)
 679 {
 680         return !!server_feature_value(feature, NULL);
 681 }
 682
 683 enum protocol {
 684         PROTO_LOCAL = 1,
 685         PROTO_FILE,
 686         PROTO_SSH,
 687         PROTO_GIT
 688 };
 689
 690 int url_is_local_not_ssh(const char *url)
 691 {
 692         const char *colon = strchr(url, ':');
 693         const char *slash = strchr(url, '/');
 694         return !colon || (slash && slash < colon) ||
 695                 (has_dos_drive_prefix(url) && is_valid_path(url));
 696 }
 697
 698 static const char *prot_name(enum protocol protocol)
 699 {
 700         switch (protocol) {
 701                 case PROTO_LOCAL:
 702                 case PROTO_FILE:
 703                         return "file";
 704                 case PROTO_SSH:
 705                         return "ssh";
 706                 case PROTO_GIT:
 707                         return "git";
 708                 default:
 709                         return "unknown protocol";
 710         }
 711 }
 712
 713 static enum protocol get_protocol(const char *name)
 714 {
 715         if (!strcmp(name, "ssh"))
 716                 return PROTO_SSH;
 717         if (!strcmp(name, "git"))
 718                 return PROTO_GIT;
 719         if (!strcmp(name, "git+ssh")) /* deprecated - do not use */
 720                 return PROTO_SSH;
 721         if (!strcmp(name, "ssh+git")) /* deprecated - do not use */
 722                 return PROTO_SSH;
 723         if (!strcmp(name, "file"))
 724                 return PROTO_FILE;
 725         die(_("protocol '%s' is not supported"), name);
 726 }
 727
 728 static char *host_end(char **hoststart, int removebrackets)
 729 {
 730         char *host = *hoststart;
 731         char *end;
 732         char *start = strstr(host, "@[");
 733         if (start)
 734                 start++; /* Jump over '@' */
 735         else
 736                 start = host;
 737         if (start[0] == '[') {
 738                 end = strchr(start + 1, ']');
 739                 if (end) {
 740                         if (removebrackets) {
 741                                 *end = 0;
 742                                 memmove(start, start + 1, end - start);
 743                                 end++;
 744                         }
 745                 } else
 746                         end = host;
 747         } else
 748                 end = host;
 749         return end;
 750 }
 751
 752 #define STR_(s) # s
 753 #define STR(s)  STR_(s)
 754
 755 static void get_host_and_port(char **host, const char **port)
 756 {
 757         char *colon, *end;
 758         end = host_end(host, 1);
 759         colon = strchr(end, ':');
 760         if (colon) {
 761                 long portnr = strtol(colon + 1, &end, 10);
 762                 if (end != colon + 1 && *end == '\0' && 0 <= portnr && portnr < 65536) {
 763                         *colon = 0;
 764                         *port = colon + 1;
 765                 } else if (!colon[1]) {
 766                         *colon = 0;
 767                 }
 768         }
 769 }
 770
 771 static void enable_keepalive(int sockfd)
 772 {
 773         int ka = 1;
 774
 775         if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
 776                 error_errno(_("unable to set SO_KEEPALIVE on socket"));
 777 }
 778
 779 #ifndef NO_IPV6
 780
 781 static const char *ai_name(const struct addrinfo *ai)
 782 {
 783         static char addr[NI_MAXHOST];
 784         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
 785                         NI_NUMERICHOST) != 0)
 786                 xsnprintf(addr, sizeof(addr), "(unknown)");
 787
 788         return addr;
 789 }
 790
 791 /*
 792  * Returns a connected socket() fd, or else die()s.
 793  */
 794 static int git_tcp_connect_sock(char *host, int flags)
 795 {
 796         struct strbuf error_message = STRBUF_INIT;
 797         int sockfd = -1;
 798         const char *port = STR(DEFAULT_GIT_PORT);
 799         struct addrinfo hints, *ai0, *ai;
 800         int gai;
 801         int cnt = 0;
 802
 803         get_host_and_port(&host, &port);
 804         if (!*port)
 805                 port = "<none>";
 806
 807         memset(&hints, 0, sizeof(hints));
 808         if (flags & CONNECT_IPV4)
 809                 hints.ai_family = AF_INET;
 810         else if (flags & CONNECT_IPV6)
 811                 hints.ai_family = AF_INET6;
 812         hints.ai_socktype = SOCK_STREAM;
 813         hints.ai_protocol = IPPROTO_TCP;
 814
 815         if (flags & CONNECT_VERBOSE)
 816                 fprintf(stderr, _("Looking up %s ... "), host);
 817
 818         gai = getaddrinfo(host, port, &hints, &ai);
 819         if (gai)
 820                 die(_("unable to look up %s (port %s) (%s)"), host, port, gai_strerror(gai));
 821
 822         if (flags & CONNECT_VERBOSE)
 823                 /* TRANSLATORS: this is the end of "Looking up %s ... " */
 824                 fprintf(stderr, _("done.\nConnecting to %s (port %s) ... "), host, port);
 825
 826         for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
 827                 sockfd = socket(ai->ai_family,
 828                                 ai->ai_socktype, ai->ai_protocol);
 829                 if ((sockfd < 0) ||
 830                     (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
 831                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 832                                     host, cnt, ai_name(ai), strerror(errno));
 833                         if (0 <= sockfd)
 834                                 close(sockfd);
 835                         sockfd = -1;
 836                         continue;
 837                 }
 838                 if (flags & CONNECT_VERBOSE)
 839                         fprintf(stderr, "%s ", ai_name(ai));
 840                 break;
 841         }
 842
 843         freeaddrinfo(ai0);
 844
 845         if (sockfd < 0)
 846                 die(_("unable to connect to %s:\n%s"), host, error_message.buf);
 847
 848         enable_keepalive(sockfd);
 849
 850         if (flags & CONNECT_VERBOSE)
 851                 /* TRANSLATORS: this is the end of "Connecting to %s (port %s) ... " */
 852                 fprintf_ln(stderr, _("done."));
 853
 854         strbuf_release(&error_message);
 855
 856         return sockfd;
 857 }
 858
 859 #else /* NO_IPV6 */
 860
 861 /*
 862  * Returns a connected socket() fd, or else die()s.
 863  */
 864 static int git_tcp_connect_sock(char *host, int flags)
 865 {
 866         struct strbuf error_message = STRBUF_INIT;
 867         int sockfd = -1;
 868         const char *port = STR(DEFAULT_GIT_PORT);
 869         char *ep;
 870         struct hostent *he;
 871         struct sockaddr_in sa;
 872         char **ap;
 873         unsigned int nport;
 874         int cnt;
 875
 876         get_host_and_port(&host, &port);
 877
 878         if (flags & CONNECT_VERBOSE)
 879                 fprintf(stderr, _("Looking up %s ... "), host);
 880
 881         he = gethostbyname(host);
 882         if (!he)
 883                 die(_("unable to look up %s (%s)"), host, hstrerror(h_errno));
 884         nport = strtoul(port, &ep, 10);
 885         if ( ep == port || *ep ) {
 886                 /* Not numeric */
 887                 struct servent *se = getservbyname(port,"tcp");
 888                 if ( !se )
 889                         die(_("unknown port %s"), port);
 890                 nport = se->s_port;
 891         }
 892
 893         if (flags & CONNECT_VERBOSE)
 894                 /* TRANSLATORS: this is the end of "Looking up %s ... " */
 895                 fprintf(stderr, _("done.\nConnecting to %s (port %s) ... "), host, port);
 896
 897         for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
 898                 memset(&sa, 0, sizeof sa);
 899                 sa.sin_family = he->h_addrtype;
 900                 sa.sin_port = htons(nport);
 901                 memcpy(&sa.sin_addr, *ap, he->h_length);
 902
 903                 sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 904                 if ((sockfd < 0) ||
 905                     connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 906                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 907                                 host,
 908                                 cnt,
 909                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr),
 910                                 strerror(errno));
 911                         if (0 <= sockfd)
 912                                 close(sockfd);
 913                         sockfd = -1;
 914                         continue;
 915                 }
 916                 if (flags & CONNECT_VERBOSE)
 917                         fprintf(stderr, "%s ",
 918                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr));
 919                 break;
 920         }
 921
 922         if (sockfd < 0)
 923                 die(_("unable to connect to %s:\n%s"), host, error_message.buf);
 924
 925         enable_keepalive(sockfd);
 926
 927         if (flags & CONNECT_VERBOSE)
 928                 /* TRANSLATORS: this is the end of "Connecting to %s (port %s) ... " */
 929                 fprintf_ln(stderr, _("done."));
 930
 931         return sockfd;
 932 }
 933
 934 #endif /* NO_IPV6 */
 935
 936
 937 /*
 938  * Dummy child_process returned by git_connect() if the transport protocol
 939  * does not need fork(2).
 940  */
 941 static struct child_process no_fork = CHILD_PROCESS_INIT;
 942
 943 int git_connection_is_socket(struct child_process *conn)
 944 {
 945         return conn == &no_fork;
 946 }
 947
 948 static struct child_process *git_tcp_connect(int fd[2], char *host, int flags)
 949 {
 950         int sockfd = git_tcp_connect_sock(host, flags);
 951
 952         fd[0] = sockfd;
 953         fd[1] = dup(sockfd);
 954
 955         return &no_fork;
 956 }
 957
 958
 959 static char *git_proxy_command;
 960
 961 static int git_proxy_command_options(const char *var, const char *value,
 962                 void *cb)
 963 {
 964         if (!strcmp(var, "core.gitproxy")) {
 965                 const char *for_pos;
 966                 int matchlen = -1;
 967                 int hostlen;
 968                 const char *rhost_name = cb;
 969                 int rhost_len = strlen(rhost_name);
 970
 971                 if (git_proxy_command)
 972                         return 0;
 973                 if (!value)
 974                         return config_error_nonbool(var);
 975                 /* [core]
 976                  * ;# matches www.kernel.org as well
 977                  * gitproxy = netcatter-1 for kernel.org
 978                  * gitproxy = netcatter-2 for sample.xz
 979                  * gitproxy = netcatter-default
 980                  */
 981                 for_pos = strstr(value, " for ");
 982                 if (!for_pos)
 983                         /* matches everybody */
 984                         matchlen = strlen(value);
 985                 else {
 986                         hostlen = strlen(for_pos + 5);
 987                         if (rhost_len < hostlen)
 988                                 matchlen = -1;
 989                         else if (!strncmp(for_pos + 5,
 990                                           rhost_name + rhost_len - hostlen,
 991                                           hostlen) &&
 992                                  ((rhost_len == hostlen) ||
 993                                   rhost_name[rhost_len - hostlen -1] == '.'))
 994                                 matchlen = for_pos - value;
 995                         else
 996                                 matchlen = -1;
 997                 }
 998                 if (0 <= matchlen) {
 999                         /* core.gitproxy = none for kernel.org */
1000                         if (matchlen == 4 &&
1001                             !memcmp(value, "none", 4))
1002                                 matchlen = 0;
1003                         git_proxy_command = xmemdupz(value, matchlen);
1004                 }
1005                 return 0;
1006         }
1007
1008         return git_default_config(var, value, cb);
1009 }
1010
1011 static int git_use_proxy(const char *host)
1012 {
1013         git_proxy_command = getenv("GIT_PROXY_COMMAND");
1014         git_config(git_proxy_command_options, (void*)host);
1015         return (git_proxy_command && *git_proxy_command);
1016 }
1017
1018 static struct child_process *git_proxy_connect(int fd[2], char *host)
1019 {
1020         const char *port = STR(DEFAULT_GIT_PORT);
1021         struct child_process *proxy;
1022
1023         get_host_and_port(&host, &port);
1024
1025         if (looks_like_command_line_option(host))
1026                 die(_("strange hostname '%s' blocked"), host);
1027         if (looks_like_command_line_option(port))
1028                 die(_("strange port '%s' blocked"), port);
1029
1030         proxy = xmalloc(sizeof(*proxy));
1031         child_process_init(proxy);
1032         strvec_push(&proxy->args, git_proxy_command);
1033         strvec_push(&proxy->args, host);
1034         strvec_push(&proxy->args, port);
1035         proxy->in = -1;
1036         proxy->out = -1;
1037         if (start_command(proxy))
1038                 die(_("cannot start proxy %s"), git_proxy_command);
1039         fd[0] = proxy->out; /* read from proxy stdout */
1040         fd[1] = proxy->in;  /* write to proxy stdin */
1041         return proxy;
1042 }
1043
1044 static char *get_port(char *host)
1045 {
1046         char *end;
1047         char *p = strchr(host, ':');
1048
1049         if (p) {
1050                 long port = strtol(p + 1, &end, 10);
1051                 if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
1052                         *p = '\0';
1053                         return p+1;
1054                 }
1055         }
1056
1057         return NULL;
1058 }
1059
1060 /*
1061  * Extract protocol and relevant parts from the specified connection URL.
1062  * The caller must free() the returned strings.
1063  */
1064 static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
1065                                        char **ret_path)
1066 {
1067         char *url;
1068         char *host, *path;
1069         char *end;
1070         int separator = '/';
1071         enum protocol protocol = PROTO_LOCAL;
1072
1073         if (is_url(url_orig))
1074                 url = url_decode(url_orig);
1075         else
1076                 url = xstrdup(url_orig);
1077
1078         host = strstr(url, "://");
1079         if (host) {
1080                 *host = '\0';
1081                 protocol = get_protocol(url);
1082                 host += 3;
1083         } else {
1084                 host = url;
1085                 if (!url_is_local_not_ssh(url)) {
1086                         protocol = PROTO_SSH;
1087                         separator = ':';
1088                 }
1089         }
1090
1091         /*
1092          * Don't do destructive transforms as protocol code does
1093          * '[]' unwrapping in get_host_and_port()
1094          */
1095         end = host_end(&host, 0);
1096
1097         if (protocol == PROTO_LOCAL)
1098                 path = end;
1099         else if (protocol == PROTO_FILE && *host != '/' &&
1100                  !has_dos_drive_prefix(host) &&
1101                  offset_1st_component(host - 2) > 1)
1102                 path = host - 2; /* include the leading "//" */
1103         else if (protocol == PROTO_FILE && has_dos_drive_prefix(end))
1104                 path = end; /* "file://$(pwd)" may be "file://C:/projects/repo" */
1105         else
1106                 path = strchr(end, separator);
1107
1108         if (!path || !*path)
1109                 die(_("no path specified; see 'git help pull' for valid url syntax"));
1110
1111         /*
1112          * null-terminate hostname and point path to ~ for URL's like this:
1113          *    ssh://host.xz/~user/repo
1114          */
1115
1116         end = path; /* Need to \0 terminate host here */
1117         if (separator == ':')
1118                 path++; /* path starts after ':' */
1119         if (protocol == PROTO_GIT || protocol == PROTO_SSH) {
1120                 if (path[1] == '~')
1121                         path++;
1122         }
1123
1124         path = xstrdup(path);
1125         *end = '\0';
1126
1127         *ret_host = xstrdup(host);
1128         *ret_path = path;
1129         free(url);
1130         return protocol;
1131 }
1132
1133 static const char *get_ssh_command(void)
1134 {
1135         const char *ssh;
1136
1137         if ((ssh = getenv("GIT_SSH_COMMAND")))
1138                 return ssh;
1139
1140         if (!git_config_get_string_tmp("core.sshcommand", &ssh))
1141                 return ssh;
1142
1143         return NULL;
1144 }
1145
1146 enum ssh_variant {
1147         VARIANT_AUTO,
1148         VARIANT_SIMPLE,
1149         VARIANT_SSH,
1150         VARIANT_PLINK,
1151         VARIANT_PUTTY,
1152         VARIANT_TORTOISEPLINK,
1153 };
1154
1155 static void override_ssh_variant(enum ssh_variant *ssh_variant)
1156 {
1157         const char *variant = getenv("GIT_SSH_VARIANT");
1158
1159         if (!variant && git_config_get_string_tmp("ssh.variant", &variant))
1160                 return;
1161
1162         if (!strcmp(variant, "auto"))
1163                 *ssh_variant = VARIANT_AUTO;
1164         else if (!strcmp(variant, "plink"))
1165                 *ssh_variant = VARIANT_PLINK;
1166         else if (!strcmp(variant, "putty"))
1167                 *ssh_variant = VARIANT_PUTTY;
1168         else if (!strcmp(variant, "tortoiseplink"))
1169                 *ssh_variant = VARIANT_TORTOISEPLINK;
1170         else if (!strcmp(variant, "simple"))
1171                 *ssh_variant = VARIANT_SIMPLE;
1172         else
1173                 *ssh_variant = VARIANT_SSH;
1174 }
1175
1176 static enum ssh_variant determine_ssh_variant(const char *ssh_command,
1177                                               int is_cmdline)
1178 {
1179         enum ssh_variant ssh_variant = VARIANT_AUTO;
1180         const char *variant;
1181         char *p = NULL;
1182
1183         override_ssh_variant(&ssh_variant);
1184
1185         if (ssh_variant != VARIANT_AUTO)
1186                 return ssh_variant;
1187
1188         if (!is_cmdline) {
1189                 p = xstrdup(ssh_command);
1190                 variant = basename(p);
1191         } else {
1192                 const char **ssh_argv;
1193
1194                 p = xstrdup(ssh_command);
1195                 if (split_cmdline(p, &ssh_argv) > 0) {
1196                         variant = basename((char *)ssh_argv[0]);
1197                         /*
1198                          * At this point, variant points into the buffer
1199                          * referenced by p, hence we do not need ssh_argv
1200                          * any longer.
1201                          */
1202                         free(ssh_argv);
1203                 } else {
1204                         free(p);
1205                         return ssh_variant;
1206                 }
1207         }
1208
1209         if (!strcasecmp(variant, "ssh") ||
1210             !strcasecmp(variant, "ssh.exe"))
1211                 ssh_variant = VARIANT_SSH;
1212         else if (!strcasecmp(variant, "plink") ||
1213                  !strcasecmp(variant, "plink.exe"))
1214                 ssh_variant = VARIANT_PLINK;
1215         else if (!strcasecmp(variant, "tortoiseplink") ||
1216                  !strcasecmp(variant, "tortoiseplink.exe"))
1217                 ssh_variant = VARIANT_TORTOISEPLINK;
1218
1219         free(p);
1220         return ssh_variant;
1221 }
1222
1223 /*
1224  * Open a connection using Git's native protocol.
1225  *
1226  * The caller is responsible for freeing hostandport, but this function may
1227  * modify it (for example, to truncate it to remove the port part).
1228  */
1229 static struct child_process *git_connect_git(int fd[2], char *hostandport,
1230                                              const char *path, const char *prog,
1231                                              enum protocol_version version,
1232                                              int flags)
1233 {
1234         struct child_process *conn;
1235         struct strbuf request = STRBUF_INIT;
1236         /*
1237          * Set up virtual host information based on where we will
1238          * connect, unless the user has overridden us in
1239          * the environment.
1240          */
1241         char *target_host = getenv("GIT_OVERRIDE_VIRTUAL_HOST");
1242         if (target_host)
1243                 target_host = xstrdup(target_host);
1244         else
1245                 target_host = xstrdup(hostandport);
1246
1247         transport_check_allowed("git");
1248         if (strchr(target_host, '\n') || strchr(path, '\n'))
1249                 die(_("newline is forbidden in git:// hosts and repo paths"));
1250
1251         /*
1252          * These underlying connection commands die() if they
1253          * cannot connect.
1254          */
1255         if (git_use_proxy(hostandport))
1256                 conn = git_proxy_connect(fd, hostandport);
1257         else
1258                 conn = git_tcp_connect(fd, hostandport, flags);
1259         /*
1260          * Separate original protocol components prog and path
1261          * from extended host header with a NUL byte.
1262          *
1263          * Note: Do not add any other headers here!  Doing so
1264          * will cause older git-daemon servers to crash.
1265          */
1266         strbuf_addf(&request,
1267                     "%s %s%chost=%s%c",
1268                     prog, path, 0,
1269                     target_host, 0);
1270
1271         /* If using a new version put that stuff here after a second null byte */
1272         if (version > 0) {
1273                 strbuf_addch(&request, '\0');
1274                 strbuf_addf(&request, "version=%d%c",
1275                             version, '\0');
1276         }
1277
1278         packet_write(fd[1], request.buf, request.len);
1279
1280         free(target_host);
1281         strbuf_release(&request);
1282         return conn;
1283 }
1284
1285 /*
1286  * Append the appropriate environment variables to `env` and options to
1287  * `args` for running ssh in Git's SSH-tunneled transport.
1288  */
1289 static void push_ssh_options(struct strvec *args, struct strvec *env,
1290                              enum ssh_variant variant, const char *port,
1291                              enum protocol_version version, int flags)
1292 {
1293         if (variant == VARIANT_SSH &&
1294             version > 0) {
1295                 strvec_push(args, "-o");
1296                 strvec_push(args, "SendEnv=" GIT_PROTOCOL_ENVIRONMENT);
1297                 strvec_pushf(env, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
1298                              version);
1299         }
1300
1301         if (flags & CONNECT_IPV4) {
1302                 switch (variant) {
1303                 case VARIANT_AUTO:
1304                         BUG("VARIANT_AUTO passed to push_ssh_options");
1305                 case VARIANT_SIMPLE:
1306                         die(_("ssh variant 'simple' does not support -4"));
1307                 case VARIANT_SSH:
1308                 case VARIANT_PLINK:
1309                 case VARIANT_PUTTY:
1310                 case VARIANT_TORTOISEPLINK:
1311                         strvec_push(args, "-4");
1312                 }
1313         } else if (flags & CONNECT_IPV6) {
1314                 switch (variant) {
1315                 case VARIANT_AUTO:
1316                         BUG("VARIANT_AUTO passed to push_ssh_options");
1317                 case VARIANT_SIMPLE:
1318                         die(_("ssh variant 'simple' does not support -6"));
1319                 case VARIANT_SSH:
1320                 case VARIANT_PLINK:
1321                 case VARIANT_PUTTY:
1322                 case VARIANT_TORTOISEPLINK:
1323                         strvec_push(args, "-6");
1324                 }
1325         }
1326
1327         if (variant == VARIANT_TORTOISEPLINK)
1328                 strvec_push(args, "-batch");
1329
1330         if (port) {
1331                 switch (variant) {
1332                 case VARIANT_AUTO:
1333                         BUG("VARIANT_AUTO passed to push_ssh_options");
1334                 case VARIANT_SIMPLE:
1335                         die(_("ssh variant 'simple' does not support setting port"));
1336                 case VARIANT_SSH:
1337                         strvec_push(args, "-p");
1338                         break;
1339                 case VARIANT_PLINK:
1340                 case VARIANT_PUTTY:
1341                 case VARIANT_TORTOISEPLINK:
1342                         strvec_push(args, "-P");
1343                 }
1344
1345                 strvec_push(args, port);
1346         }
1347 }
1348
1349 /* Prepare a child_process for use by Git's SSH-tunneled transport. */
1350 static void fill_ssh_args(struct child_process *conn, const char *ssh_host,
1351                           const char *port, enum protocol_version version,
1352                           int flags)
1353 {
1354         const char *ssh;
1355         enum ssh_variant variant;
1356
1357         if (looks_like_command_line_option(ssh_host))
1358                 die(_("strange hostname '%s' blocked"), ssh_host);
1359
1360         ssh = get_ssh_command();
1361         if (ssh) {
1362                 variant = determine_ssh_variant(ssh, 1);
1363         } else {
1364                 /*
1365                  * GIT_SSH is the no-shell version of
1366                  * GIT_SSH_COMMAND (and must remain so for
1367                  * historical compatibility).
1368                  */
1369                 conn->use_shell = 0;
1370
1371                 ssh = getenv("GIT_SSH");
1372                 if (!ssh)
1373                         ssh = "ssh";
1374                 variant = determine_ssh_variant(ssh, 0);
1375         }
1376
1377         if (variant == VARIANT_AUTO) {
1378                 struct child_process detect = CHILD_PROCESS_INIT;
1379
1380                 detect.use_shell = conn->use_shell;
1381                 detect.no_stdin = detect.no_stdout = detect.no_stderr = 1;
1382
1383                 strvec_push(&detect.args, ssh);
1384                 strvec_push(&detect.args, "-G");
1385                 push_ssh_options(&detect.args, &detect.env,
1386                                  VARIANT_SSH, port, version, flags);
1387                 strvec_push(&detect.args, ssh_host);
1388
1389                 variant = run_command(&detect) ? VARIANT_SIMPLE : VARIANT_SSH;
1390         }
1391
1392         strvec_push(&conn->args, ssh);
1393         push_ssh_options(&conn->args, &conn->env, variant, port, version,
1394                          flags);
1395         strvec_push(&conn->args, ssh_host);
1396 }
1397
1398 /*
1399  * This returns the dummy child_process `no_fork` if the transport protocol
1400  * does not need fork(2), or a struct child_process object if it does.  Once
1401  * done, finish the connection with finish_connect() with the value returned
1402  * from this function (it is safe to call finish_connect() with NULL to
1403  * support the former case).
1404  *
1405  * If it returns, the connect is successful; it just dies on errors (this
1406  * will hopefully be changed in a libification effort, to return NULL when
1407  * the connection failed).
1408  */
1409 struct child_process *git_connect(int fd[2], const char *url,
1410                                   const char *prog, int flags)
1411 {
1412         char *hostandport, *path;
1413         struct child_process *conn;
1414         enum protocol protocol;
1415         enum protocol_version version = get_protocol_version_config();
1416
1417         /*
1418          * NEEDSWORK: If we are trying to use protocol v2 and we are planning
1419          * to perform a push, then fallback to v0 since the client doesn't know
1420          * how to push yet using v2.
1421          */
1422         if (version == protocol_v2 && !strcmp("git-receive-pack", prog))
1423                 version = protocol_v0;
1424
1425         /* Without this we cannot rely on waitpid() to tell
1426          * what happened to our children.
1427          */
1428         signal(SIGCHLD, SIG_DFL);
1429
1430         protocol = parse_connect_url(url, &hostandport, &path);
1431         if ((flags & CONNECT_DIAG_URL) && (protocol != PROTO_SSH)) {
1432                 printf("Diag: url=%s\n", url ? url : "NULL");
1433                 printf("Diag: protocol=%s\n", prot_name(protocol));
1434                 printf("Diag: hostandport=%s\n", hostandport ? hostandport : "NULL");
1435                 printf("Diag: path=%s\n", path ? path : "NULL");
1436                 conn = NULL;
1437         } else if (protocol == PROTO_GIT) {
1438                 conn = git_connect_git(fd, hostandport, path, prog, version, flags);
1439                 conn->trace2_child_class = "transport/git";
1440         } else {
1441                 struct strbuf cmd = STRBUF_INIT;
1442                 const char *const *var;
1443
1444                 conn = xmalloc(sizeof(*conn));
1445                 child_process_init(conn);
1446
1447                 if (looks_like_command_line_option(path))
1448                         die(_("strange pathname '%s' blocked"), path);
1449
1450                 strbuf_addstr(&cmd, prog);
1451                 strbuf_addch(&cmd, ' ');
1452                 sq_quote_buf(&cmd, path);
1453
1454                 /* remove repo-local variables from the environment */
1455                 for (var = local_repo_env; *var; var++)
1456                         strvec_push(&conn->env, *var);
1457
1458                 conn->use_shell = 1;
1459                 conn->in = conn->out = -1;
1460                 if (protocol == PROTO_SSH) {
1461                         char *ssh_host = hostandport;
1462                         const char *port = NULL;
1463                         transport_check_allowed("ssh");
1464                         get_host_and_port(&ssh_host, &port);
1465
1466                         if (!port)
1467                                 port = get_port(ssh_host);
1468
1469                         if (flags & CONNECT_DIAG_URL) {
1470                                 printf("Diag: url=%s\n", url ? url : "NULL");
1471                                 printf("Diag: protocol=%s\n", prot_name(protocol));
1472                                 printf("Diag: userandhost=%s\n", ssh_host ? ssh_host : "NULL");
1473                                 printf("Diag: port=%s\n", port ? port : "NONE");
1474                                 printf("Diag: path=%s\n", path ? path : "NULL");
1475
1476                                 free(hostandport);
1477                                 free(path);
1478                                 free(conn);
1479                                 strbuf_release(&cmd);
1480                                 return NULL;
1481                         }
1482                         conn->trace2_child_class = "transport/ssh";
1483                         fill_ssh_args(conn, ssh_host, port, version, flags);
1484                 } else {
1485                         transport_check_allowed("file");
1486                         conn->trace2_child_class = "transport/file";
1487                         if (version > 0) {
1488                                 strvec_pushf(&conn->env,
1489                                              GIT_PROTOCOL_ENVIRONMENT "=version=%d",
1490                                              version);
1491                         }
1492                 }
1493                 strvec_push(&conn->args, cmd.buf);
1494
1495                 if (start_command(conn))
1496                         die(_("unable to fork"));
1497
1498                 fd[0] = conn->out; /* read from child's stdout */
1499                 fd[1] = conn->in;  /* write to child's stdin */
1500                 strbuf_release(&cmd);
1501         }
1502         free(hostandport);
1503         free(path);
1504         return conn;
1505 }
1506
1507 int finish_connect(struct child_process *conn)
1508 {
1509         int code;
1510         if (!conn || git_connection_is_socket(conn))
1511                 return 0;
1512
1513         code = finish_command(conn);
1514         free(conn);
1515         return code;
1516 }