connect.c

   1 #include "git-compat-util.h"
   2 #include "config.h"
   3 #include "environment.h"
   4 #include "gettext.h"
   5 #include "hex.h"
   6 #include "pkt-line.h"
   7 #include "quote.h"
   8 #include "refs.h"
   9 #include "run-command.h"
  10 #include "remote.h"
  11 #include "connect.h"
  12 #include "url.h"
  13 #include "string-list.h"
  14 #include "oid-array.h"
  15 #include "transport.h"
  16 #include "trace2.h"
  17 #include "strbuf.h"
  18 #include "version.h"
  19 #include "protocol.h"
  20 #include "alias.h"
  21 #include "bundle-uri.h"
  22
  23 static char *server_capabilities_v1;
  24 static struct strvec server_capabilities_v2 = STRVEC_INIT;
  25 static const char *next_server_feature_value(const char *feature, size_t *len, size_t *offset);
  26
  27 static int check_ref(const char *name, unsigned int flags)
  28 {
  29         if (!flags)
  30                 return 1;
  31
  32         if (!skip_prefix(name, "refs/", &name))
  33                 return 0;
  34
  35         /* REF_NORMAL means that we don't want the magic fake tag refs */
  36         if ((flags & REF_NORMAL) && check_refname_format(name,
  37                                                          REFNAME_ALLOW_ONELEVEL))
  38                 return 0;
  39
  40         /* REF_HEADS means that we want regular branch heads */
  41         if ((flags & REF_HEADS) && starts_with(name, "heads/"))
  42                 return 1;
  43
  44         /* REF_TAGS means that we want tags */
  45         if ((flags & REF_TAGS) && starts_with(name, "tags/"))
  46                 return 1;
  47
  48         /* All type bits clear means that we are ok with anything */
  49         return !(flags & ~REF_NORMAL);
  50 }
  51
  52 int check_ref_type(const struct ref *ref, int flags)
  53 {
  54         return check_ref(ref->name, flags);
  55 }
  56
  57 static NORETURN void die_initial_contact(int unexpected)
  58 {
  59         /*
  60          * A hang-up after seeing some response from the other end
  61          * means that it is unexpected, as we know the other end is
  62          * willing to talk to us.  A hang-up before seeing any
  63          * response does not necessarily mean an ACL problem, though.
  64          */
  65         if (unexpected)
  66                 die(_("the remote end hung up upon initial contact"));
  67         else
  68                 die(_("Could not read from remote repository.\n\n"
  69                       "Please make sure you have the correct access rights\n"
  70                       "and the repository exists."));
  71 }
  72
  73 /* Checks if the server supports the capability 'c' */
  74 int server_supports_v2(const char *c)
  75 {
  76         int i;
  77
  78         for (i = 0; i < server_capabilities_v2.nr; i++) {
  79                 const char *out;
  80                 if (skip_prefix(server_capabilities_v2.v[i], c, &out) &&
  81                     (!*out || *out == '='))
  82                         return 1;
  83         }
  84         return 0;
  85 }
  86
  87 void ensure_server_supports_v2(const char *c)
  88 {
  89         if (!server_supports_v2(c))
  90                 die(_("server doesn't support '%s'"), c);
  91 }
  92
  93 int server_feature_v2(const char *c, const char **v)
  94 {
  95         int i;
  96
  97         for (i = 0; i < server_capabilities_v2.nr; i++) {
  98                 const char *out;
  99                 if (skip_prefix(server_capabilities_v2.v[i], c, &out) &&
 100                     (*out == '=')) {
 101                         *v = out + 1;
 102                         return 1;
 103                 }
 104         }
 105         return 0;
 106 }
 107
 108 int server_supports_feature(const char *c, const char *feature,
 109                             int die_on_error)
 110 {
 111         int i;
 112
 113         for (i = 0; i < server_capabilities_v2.nr; i++) {
 114                 const char *out;
 115                 if (skip_prefix(server_capabilities_v2.v[i], c, &out) &&
 116                     (!*out || *(out++) == '=')) {
 117                         if (parse_feature_request(out, feature))
 118                                 return 1;
 119                         else
 120                                 break;
 121                 }
 122         }
 123
 124         if (die_on_error)
 125                 die(_("server doesn't support feature '%s'"), feature);
 126
 127         return 0;
 128 }
 129
 130 static void process_capabilities_v2(struct packet_reader *reader)
 131 {
 132         while (packet_reader_read(reader) == PACKET_READ_NORMAL)
 133                 strvec_push(&server_capabilities_v2, reader->line);
 134
 135         if (reader->status != PACKET_READ_FLUSH)
 136                 die(_("expected flush after capabilities"));
 137 }
 138
 139 enum protocol_version discover_version(struct packet_reader *reader)
 140 {
 141         enum protocol_version version = protocol_unknown_version;
 142
 143         /*
 144          * Peek the first line of the server's response to
 145          * determine the protocol version the server is speaking.
 146          */
 147         switch (packet_reader_peek(reader)) {
 148         case PACKET_READ_EOF:
 149                 die_initial_contact(0);
 150         case PACKET_READ_FLUSH:
 151         case PACKET_READ_DELIM:
 152         case PACKET_READ_RESPONSE_END:
 153                 version = protocol_v0;
 154                 break;
 155         case PACKET_READ_NORMAL:
 156                 version = determine_protocol_version_client(reader->line);
 157                 break;
 158         }
 159
 160         switch (version) {
 161         case protocol_v2:
 162                 process_capabilities_v2(reader);
 163                 break;
 164         case protocol_v1:
 165                 /* Read the peeked version line */
 166                 packet_reader_read(reader);
 167                 break;
 168         case protocol_v0:
 169                 break;
 170         case protocol_unknown_version:
 171                 BUG("unknown protocol version");
 172         }
 173
 174         trace2_data_intmax("transfer", NULL, "negotiated-version", version);
 175
 176         return version;
 177 }
 178
 179 static void parse_one_symref_info(struct string_list *symref, const char *val, int len)
 180 {
 181         char *sym, *target;
 182         struct string_list_item *item;
 183
 184         if (!len)
 185                 return; /* just "symref" */
 186         /* e.g. "symref=HEAD:refs/heads/master" */
 187         sym = xmemdupz(val, len);
 188         target = strchr(sym, ':');
 189         if (!target)
 190                 /* just "symref=something" */
 191                 goto reject;
 192         *(target++) = '\0';
 193         if (check_refname_format(sym, REFNAME_ALLOW_ONELEVEL) ||
 194             check_refname_format(target, REFNAME_ALLOW_ONELEVEL))
 195                 /* "symref=bogus:pair */
 196                 goto reject;
 197         item = string_list_append_nodup(symref, sym);
 198         item->util = target;
 199         return;
 200 reject:
 201         free(sym);
 202         return;
 203 }
 204
 205 static void annotate_refs_with_symref_info(struct ref *ref)
 206 {
 207         struct string_list symref = STRING_LIST_INIT_DUP;
 208         size_t offset = 0;
 209
 210         while (1) {
 211                 size_t len;
 212                 const char *val;
 213
 214                 val = next_server_feature_value("symref", &len, &offset);
 215                 if (!val)
 216                         break;
 217                 parse_one_symref_info(&symref, val, len);
 218         }
 219         string_list_sort(&symref);
 220
 221         for (; ref; ref = ref->next) {
 222                 struct string_list_item *item;
 223                 item = string_list_lookup(&symref, ref->name);
 224                 if (!item)
 225                         continue;
 226                 ref->symref = xstrdup((char *)item->util);
 227         }
 228         string_list_clear(&symref, 0);
 229 }
 230
 231 static void process_capabilities(struct packet_reader *reader, int *linelen)
 232 {
 233         const char *feat_val;
 234         size_t feat_len;
 235         const char *line = reader->line;
 236         int nul_location = strlen(line);
 237         if (nul_location == *linelen)
 238                 return;
 239         server_capabilities_v1 = xstrdup(line + nul_location + 1);
 240         *linelen = nul_location;
 241
 242         feat_val = server_feature_value("object-format", &feat_len);
 243         if (feat_val) {
 244                 char *hash_name = xstrndup(feat_val, feat_len);
 245                 int hash_algo = hash_algo_by_name(hash_name);
 246                 if (hash_algo != GIT_HASH_UNKNOWN)
 247                         reader->hash_algo = &hash_algos[hash_algo];
 248                 free(hash_name);
 249         } else {
 250                 reader->hash_algo = &hash_algos[GIT_HASH_SHA1];
 251         }
 252 }
 253
 254 static int process_dummy_ref(const struct packet_reader *reader)
 255 {
 256         const char *line = reader->line;
 257         struct object_id oid;
 258         const char *name;
 259
 260         if (parse_oid_hex_algop(line, &oid, &name, reader->hash_algo))
 261                 return 0;
 262         if (*name != ' ')
 263                 return 0;
 264         name++;
 265
 266         return oideq(reader->hash_algo->null_oid, &oid) &&
 267                 !strcmp(name, "capabilities^{}");
 268 }
 269
 270 static void check_no_capabilities(const char *line, int len)
 271 {
 272         if (strlen(line) != len)
 273                 warning(_("ignoring capabilities after first line '%s'"),
 274                         line + strlen(line));
 275 }
 276
 277 static int process_ref(const struct packet_reader *reader, int len,
 278                        struct ref ***list, unsigned int flags,
 279                        struct oid_array *extra_have)
 280 {
 281         const char *line = reader->line;
 282         struct object_id old_oid;
 283         const char *name;
 284
 285         if (parse_oid_hex_algop(line, &old_oid, &name, reader->hash_algo))
 286                 return 0;
 287         if (*name != ' ')
 288                 return 0;
 289         name++;
 290
 291         if (extra_have && !strcmp(name, ".have")) {
 292                 oid_array_append(extra_have, &old_oid);
 293         } else if (!strcmp(name, "capabilities^{}")) {
 294                 die(_("protocol error: unexpected capabilities^{}"));
 295         } else if (check_ref(name, flags)) {
 296                 struct ref *ref = alloc_ref(name);
 297                 oidcpy(&ref->old_oid, &old_oid);
 298                 **list = ref;
 299                 *list = &ref->next;
 300         }
 301         check_no_capabilities(line, len);
 302         return 1;
 303 }
 304
 305 static int process_shallow(const struct packet_reader *reader, int len,
 306                            struct oid_array *shallow_points)
 307 {
 308         const char *line = reader->line;
 309         const char *arg;
 310         struct object_id old_oid;
 311
 312         if (!skip_prefix(line, "shallow ", &arg))
 313                 return 0;
 314
 315         if (get_oid_hex_algop(arg, &old_oid, reader->hash_algo))
 316                 die(_("protocol error: expected shallow sha-1, got '%s'"), arg);
 317         if (!shallow_points)
 318                 die(_("repository on the other end cannot be shallow"));
 319         oid_array_append(shallow_points, &old_oid);
 320         check_no_capabilities(line, len);
 321         return 1;
 322 }
 323
 324 enum get_remote_heads_state {
 325         EXPECTING_FIRST_REF = 0,
 326         EXPECTING_REF,
 327         EXPECTING_SHALLOW,
 328         EXPECTING_DONE,
 329 };
 330
 331 /*
 332  * Read all the refs from the other end
 333  */
 334 struct ref **get_remote_heads(struct packet_reader *reader,
 335                               struct ref **list, unsigned int flags,
 336                               struct oid_array *extra_have,
 337                               struct oid_array *shallow_points)
 338 {
 339         struct ref **orig_list = list;
 340         int len = 0;
 341         enum get_remote_heads_state state = EXPECTING_FIRST_REF;
 342
 343         *list = NULL;
 344
 345         while (state != EXPECTING_DONE) {
 346                 switch (packet_reader_read(reader)) {
 347                 case PACKET_READ_EOF:
 348                         die_initial_contact(1);
 349                 case PACKET_READ_NORMAL:
 350                         len = reader->pktlen;
 351                         break;
 352                 case PACKET_READ_FLUSH:
 353                         state = EXPECTING_DONE;
 354                         break;
 355                 case PACKET_READ_DELIM:
 356                 case PACKET_READ_RESPONSE_END:
 357                         die(_("invalid packet"));
 358                 }
 359
 360                 switch (state) {
 361                 case EXPECTING_FIRST_REF:
 362                         process_capabilities(reader, &len);
 363                         if (process_dummy_ref(reader)) {
 364                                 state = EXPECTING_SHALLOW;
 365                                 break;
 366                         }
 367                         state = EXPECTING_REF;
 368                         /* fallthrough */
 369                 case EXPECTING_REF:
 370                         if (process_ref(reader, len, &list, flags, extra_have))
 371                                 break;
 372                         state = EXPECTING_SHALLOW;
 373                         /* fallthrough */
 374                 case EXPECTING_SHALLOW:
 375                         if (process_shallow(reader, len, shallow_points))
 376                                 break;
 377                         die(_("protocol error: unexpected '%s'"), reader->line);
 378                 case EXPECTING_DONE:
 379                         break;
 380                 }
 381         }
 382
 383         annotate_refs_with_symref_info(*orig_list);
 384
 385         return list;
 386 }
 387
 388 /* Returns 1 when a valid ref has been added to `list`, 0 otherwise */
 389 static int process_ref_v2(struct packet_reader *reader, struct ref ***list,
 390                           const char **unborn_head_target)
 391 {
 392         int ret = 1;
 393         int i = 0;
 394         struct object_id old_oid;
 395         struct ref *ref;
 396         struct string_list line_sections = STRING_LIST_INIT_DUP;
 397         const char *end;
 398         const char *line = reader->line;
 399
 400         /*
 401          * Ref lines have a number of fields which are space deliminated.  The
 402          * first field is the OID of the ref.  The second field is the ref
 403          * name.  Subsequent fields (symref-target and peeled) are optional and
 404          * don't have a particular order.
 405          */
 406         if (string_list_split(&line_sections, line, ' ', -1) < 2) {
 407                 ret = 0;
 408                 goto out;
 409         }
 410
 411         if (!strcmp("unborn", line_sections.items[i].string)) {
 412                 i++;
 413                 if (unborn_head_target &&
 414                     !strcmp("HEAD", line_sections.items[i++].string)) {
 415                         /*
 416                          * Look for the symref target (if any). If found,
 417                          * return it to the caller.
 418                          */
 419                         for (; i < line_sections.nr; i++) {
 420                                 const char *arg = line_sections.items[i].string;
 421
 422                                 if (skip_prefix(arg, "symref-target:", &arg)) {
 423                                         *unborn_head_target = xstrdup(arg);
 424                                         break;
 425                                 }
 426                         }
 427                 }
 428                 goto out;
 429         }
 430         if (parse_oid_hex_algop(line_sections.items[i++].string, &old_oid, &end, reader->hash_algo) ||
 431             *end) {
 432                 ret = 0;
 433                 goto out;
 434         }
 435
 436         ref = alloc_ref(line_sections.items[i++].string);
 437
 438         memcpy(ref->old_oid.hash, old_oid.hash, reader->hash_algo->rawsz);
 439         **list = ref;
 440         *list = &ref->next;
 441
 442         for (; i < line_sections.nr; i++) {
 443                 const char *arg = line_sections.items[i].string;
 444                 if (skip_prefix(arg, "symref-target:", &arg))
 445                         ref->symref = xstrdup(arg);
 446
 447                 if (skip_prefix(arg, "peeled:", &arg)) {
 448                         struct object_id peeled_oid;
 449                         char *peeled_name;
 450                         struct ref *peeled;
 451                         if (parse_oid_hex_algop(arg, &peeled_oid, &end,
 452                                                 reader->hash_algo) || *end) {
 453                                 ret = 0;
 454                                 goto out;
 455                         }
 456
 457                         peeled_name = xstrfmt("%s^{}", ref->name);
 458                         peeled = alloc_ref(peeled_name);
 459
 460                         memcpy(peeled->old_oid.hash, peeled_oid.hash,
 461                                reader->hash_algo->rawsz);
 462                         **list = peeled;
 463                         *list = &peeled->next;
 464
 465                         free(peeled_name);
 466                 }
 467         }
 468
 469 out:
 470         string_list_clear(&line_sections, 0);
 471         return ret;
 472 }
 473
 474 void check_stateless_delimiter(int stateless_rpc,
 475                               struct packet_reader *reader,
 476                               const char *error)
 477 {
 478         if (!stateless_rpc)
 479                 return; /* not in stateless mode, no delimiter expected */
 480         if (packet_reader_read(reader) != PACKET_READ_RESPONSE_END)
 481                 die("%s", error);
 482 }
 483
 484 static void send_capabilities(int fd_out, struct packet_reader *reader)
 485 {
 486         const char *hash_name;
 487
 488         if (server_supports_v2("agent"))
 489                 packet_write_fmt(fd_out, "agent=%s", git_user_agent_sanitized());
 490
 491         if (server_feature_v2("object-format", &hash_name)) {
 492                 int hash_algo = hash_algo_by_name(hash_name);
 493                 if (hash_algo == GIT_HASH_UNKNOWN)
 494                         die(_("unknown object format '%s' specified by server"), hash_name);
 495                 reader->hash_algo = &hash_algos[hash_algo];
 496                 packet_write_fmt(fd_out, "object-format=%s", reader->hash_algo->name);
 497         } else {
 498                 reader->hash_algo = &hash_algos[GIT_HASH_SHA1];
 499         }
 500 }
 501
 502 int get_remote_bundle_uri(int fd_out, struct packet_reader *reader,
 503                           struct bundle_list *bundles, int stateless_rpc)
 504 {
 505         int line_nr = 1;
 506
 507         /* Assert bundle-uri support */
 508         ensure_server_supports_v2("bundle-uri");
 509
 510         /* (Re-)send capabilities */
 511         send_capabilities(fd_out, reader);
 512
 513         /* Send command */
 514         packet_write_fmt(fd_out, "command=bundle-uri\n");
 515         packet_delim(fd_out);
 516
 517         packet_flush(fd_out);
 518
 519         /* Process response from server */
 520         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
 521                 const char *line = reader->line;
 522                 line_nr++;
 523
 524                 if (!bundle_uri_parse_line(bundles, line))
 525                         continue;
 526
 527                 return error(_("error on bundle-uri response line %d: %s"),
 528                              line_nr, line);
 529         }
 530
 531         if (reader->status != PACKET_READ_FLUSH)
 532                 return error(_("expected flush after bundle-uri listing"));
 533
 534         /*
 535          * Might die(), but obscure enough that that's OK, e.g. in
 536          * serve.c we'll call BUG() on its equivalent (the
 537          * PACKET_READ_RESPONSE_END check).
 538          */
 539         check_stateless_delimiter(stateless_rpc, reader,
 540                                   _("expected response end packet after ref listing"));
 541
 542         return 0;
 543 }
 544
 545 struct ref **get_remote_refs(int fd_out, struct packet_reader *reader,
 546                              struct ref **list, int for_push,
 547                              struct transport_ls_refs_options *transport_options,
 548                              const struct string_list *server_options,
 549                              int stateless_rpc)
 550 {
 551         int i;
 552         struct strvec *ref_prefixes = transport_options ?
 553                 &transport_options->ref_prefixes : NULL;
 554         const char **unborn_head_target = transport_options ?
 555                 &transport_options->unborn_head_target : NULL;
 556         *list = NULL;
 557
 558         ensure_server_supports_v2("ls-refs");
 559         packet_write_fmt(fd_out, "command=ls-refs\n");
 560
 561         /* Send capabilities */
 562         send_capabilities(fd_out, reader);
 563
 564         if (server_options && server_options->nr) {
 565                 ensure_server_supports_v2("server-option");
 566                 for (i = 0; i < server_options->nr; i++)
 567                         packet_write_fmt(fd_out, "server-option=%s",
 568                                          server_options->items[i].string);
 569         }
 570
 571         packet_delim(fd_out);
 572         /* When pushing we don't want to request the peeled tags */
 573         if (!for_push)
 574                 packet_write_fmt(fd_out, "peel\n");
 575         packet_write_fmt(fd_out, "symrefs\n");
 576         if (server_supports_feature("ls-refs", "unborn", 0))
 577                 packet_write_fmt(fd_out, "unborn\n");
 578         for (i = 0; ref_prefixes && i < ref_prefixes->nr; i++) {
 579                 packet_write_fmt(fd_out, "ref-prefix %s\n",
 580                                  ref_prefixes->v[i]);
 581         }
 582         packet_flush(fd_out);
 583
 584         /* Process response from server */
 585         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
 586                 if (!process_ref_v2(reader, &list, unborn_head_target))
 587                         die(_("invalid ls-refs response: %s"), reader->line);
 588         }
 589
 590         if (reader->status != PACKET_READ_FLUSH)
 591                 die(_("expected flush after ref listing"));
 592
 593         check_stateless_delimiter(stateless_rpc, reader,
 594                                   _("expected response end packet after ref listing"));
 595
 596         return list;
 597 }
 598
 599 const char *parse_feature_value(const char *feature_list, const char *feature, size_t *lenp, size_t *offset)
 600 {
 601         const char *orig_start = feature_list;
 602         size_t len;
 603
 604         if (!feature_list)
 605                 return NULL;
 606
 607         len = strlen(feature);
 608         if (offset)
 609                 feature_list += *offset;
 610         while (*feature_list) {
 611                 const char *found = strstr(feature_list, feature);
 612                 if (!found)
 613                         return NULL;
 614                 if (feature_list == found || isspace(found[-1])) {
 615                         const char *value = found + len;
 616                         /* feature with no value (e.g., "thin-pack") */
 617                         if (!*value || isspace(*value)) {
 618                                 if (lenp)
 619                                         *lenp = 0;
 620                                 if (offset)
 621                                         *offset = found + len - orig_start;
 622                                 return value;
 623                         }
 624                         /* feature with a value (e.g., "agent=git/1.2.3") */
 625                         else if (*value == '=') {
 626                                 size_t end;
 627
 628                                 value++;
 629                                 end = strcspn(value, " \t\n");
 630                                 if (lenp)
 631                                         *lenp = end;
 632                                 if (offset)
 633                                         *offset = value + end - orig_start;
 634                                 return value;
 635                         }
 636                         /*
 637                          * otherwise we matched a substring of another feature;
 638                          * keep looking
 639                          */
 640                 }
 641                 feature_list = found + 1;
 642         }
 643         return NULL;
 644 }
 645
 646 int server_supports_hash(const char *desired, int *feature_supported)
 647 {
 648         size_t offset = 0;
 649         size_t len;
 650         const char *hash;
 651
 652         hash = next_server_feature_value("object-format", &len, &offset);
 653         if (feature_supported)
 654                 *feature_supported = !!hash;
 655         if (!hash) {
 656                 hash = hash_algos[GIT_HASH_SHA1].name;
 657                 len = strlen(hash);
 658         }
 659         while (hash) {
 660                 if (!xstrncmpz(desired, hash, len))
 661                         return 1;
 662
 663                 hash = next_server_feature_value("object-format", &len, &offset);
 664         }
 665         return 0;
 666 }
 667
 668 int parse_feature_request(const char *feature_list, const char *feature)
 669 {
 670         return !!parse_feature_value(feature_list, feature, NULL, NULL);
 671 }
 672
 673 static const char *next_server_feature_value(const char *feature, size_t *len, size_t *offset)
 674 {
 675         return parse_feature_value(server_capabilities_v1, feature, len, offset);
 676 }
 677
 678 const char *server_feature_value(const char *feature, size_t *len)
 679 {
 680         return parse_feature_value(server_capabilities_v1, feature, len, NULL);
 681 }
 682
 683 int server_supports(const char *feature)
 684 {
 685         return !!server_feature_value(feature, NULL);
 686 }
 687
 688 enum protocol {
 689         PROTO_LOCAL = 1,
 690         PROTO_FILE,
 691         PROTO_SSH,
 692         PROTO_GIT
 693 };
 694
 695 int url_is_local_not_ssh(const char *url)
 696 {
 697         const char *colon = strchr(url, ':');
 698         const char *slash = strchr(url, '/');
 699         return !colon || (slash && slash < colon) ||
 700                 (has_dos_drive_prefix(url) && is_valid_path(url));
 701 }
 702
 703 static const char *prot_name(enum protocol protocol)
 704 {
 705         switch (protocol) {
 706                 case PROTO_LOCAL:
 707                 case PROTO_FILE:
 708                         return "file";
 709                 case PROTO_SSH:
 710                         return "ssh";
 711                 case PROTO_GIT:
 712                         return "git";
 713                 default:
 714                         return "unknown protocol";
 715         }
 716 }
 717
 718 static enum protocol get_protocol(const char *name)
 719 {
 720         if (!strcmp(name, "ssh"))
 721                 return PROTO_SSH;
 722         if (!strcmp(name, "git"))
 723                 return PROTO_GIT;
 724         if (!strcmp(name, "git+ssh")) /* deprecated - do not use */
 725                 return PROTO_SSH;
 726         if (!strcmp(name, "ssh+git")) /* deprecated - do not use */
 727                 return PROTO_SSH;
 728         if (!strcmp(name, "file"))
 729                 return PROTO_FILE;
 730         die(_("protocol '%s' is not supported"), name);
 731 }
 732
 733 static char *host_end(char **hoststart, int removebrackets)
 734 {
 735         char *host = *hoststart;
 736         char *end;
 737         char *start = strstr(host, "@[");
 738         if (start)
 739                 start++; /* Jump over '@' */
 740         else
 741                 start = host;
 742         if (start[0] == '[') {
 743                 end = strchr(start + 1, ']');
 744                 if (end) {
 745                         if (removebrackets) {
 746                                 *end = 0;
 747                                 memmove(start, start + 1, end - start);
 748                                 end++;
 749                         }
 750                 } else
 751                         end = host;
 752         } else
 753                 end = host;
 754         return end;
 755 }
 756
 757 #define STR_(s) # s
 758 #define STR(s)  STR_(s)
 759
 760 static void get_host_and_port(char **host, const char **port)
 761 {
 762         char *colon, *end;
 763         end = host_end(host, 1);
 764         colon = strchr(end, ':');
 765         if (colon) {
 766                 long portnr = strtol(colon + 1, &end, 10);
 767                 if (end != colon + 1 && *end == '\0' && 0 <= portnr && portnr < 65536) {
 768                         *colon = 0;
 769                         *port = colon + 1;
 770                 } else if (!colon[1]) {
 771                         *colon = 0;
 772                 }
 773         }
 774 }
 775
 776 static void enable_keepalive(int sockfd)
 777 {
 778         int ka = 1;
 779
 780         if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
 781                 error_errno(_("unable to set SO_KEEPALIVE on socket"));
 782 }
 783
 784 #ifndef NO_IPV6
 785
 786 static const char *ai_name(const struct addrinfo *ai)
 787 {
 788         static char addr[NI_MAXHOST];
 789         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
 790                         NI_NUMERICHOST) != 0)
 791                 xsnprintf(addr, sizeof(addr), "(unknown)");
 792
 793         return addr;
 794 }
 795
 796 /*
 797  * Returns a connected socket() fd, or else die()s.
 798  */
 799 static int git_tcp_connect_sock(char *host, int flags)
 800 {
 801         struct strbuf error_message = STRBUF_INIT;
 802         int sockfd = -1;
 803         const char *port = STR(DEFAULT_GIT_PORT);
 804         struct addrinfo hints, *ai0, *ai;
 805         int gai;
 806         int cnt = 0;
 807
 808         get_host_and_port(&host, &port);
 809         if (!*port)
 810                 port = "<none>";
 811
 812         memset(&hints, 0, sizeof(hints));
 813         if (flags & CONNECT_IPV4)
 814                 hints.ai_family = AF_INET;
 815         else if (flags & CONNECT_IPV6)
 816                 hints.ai_family = AF_INET6;
 817         hints.ai_socktype = SOCK_STREAM;
 818         hints.ai_protocol = IPPROTO_TCP;
 819
 820         if (flags & CONNECT_VERBOSE)
 821                 fprintf(stderr, _("Looking up %s ... "), host);
 822
 823         gai = getaddrinfo(host, port, &hints, &ai);
 824         if (gai)
 825                 die(_("unable to look up %s (port %s) (%s)"), host, port, gai_strerror(gai));
 826
 827         if (flags & CONNECT_VERBOSE)
 828                 /* TRANSLATORS: this is the end of "Looking up %s ... " */
 829                 fprintf(stderr, _("done.\nConnecting to %s (port %s) ... "), host, port);
 830
 831         for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
 832                 sockfd = socket(ai->ai_family,
 833                                 ai->ai_socktype, ai->ai_protocol);
 834                 if ((sockfd < 0) ||
 835                     (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
 836                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 837                                     host, cnt, ai_name(ai), strerror(errno));
 838                         if (0 <= sockfd)
 839                                 close(sockfd);
 840                         sockfd = -1;
 841                         continue;
 842                 }
 843                 if (flags & CONNECT_VERBOSE)
 844                         fprintf(stderr, "%s ", ai_name(ai));
 845                 break;
 846         }
 847
 848         freeaddrinfo(ai0);
 849
 850         if (sockfd < 0)
 851                 die(_("unable to connect to %s:\n%s"), host, error_message.buf);
 852
 853         enable_keepalive(sockfd);
 854
 855         if (flags & CONNECT_VERBOSE)
 856                 /* TRANSLATORS: this is the end of "Connecting to %s (port %s) ... " */
 857                 fprintf_ln(stderr, _("done."));
 858
 859         strbuf_release(&error_message);
 860
 861         return sockfd;
 862 }
 863
 864 #else /* NO_IPV6 */
 865
 866 /*
 867  * Returns a connected socket() fd, or else die()s.
 868  */
 869 static int git_tcp_connect_sock(char *host, int flags)
 870 {
 871         struct strbuf error_message = STRBUF_INIT;
 872         int sockfd = -1;
 873         const char *port = STR(DEFAULT_GIT_PORT);
 874         char *ep;
 875         struct hostent *he;
 876         struct sockaddr_in sa;
 877         char **ap;
 878         unsigned int nport;
 879         int cnt;
 880
 881         get_host_and_port(&host, &port);
 882
 883         if (flags & CONNECT_VERBOSE)
 884                 fprintf(stderr, _("Looking up %s ... "), host);
 885
 886         he = gethostbyname(host);
 887         if (!he)
 888                 die(_("unable to look up %s (%s)"), host, hstrerror(h_errno));
 889         nport = strtoul(port, &ep, 10);
 890         if ( ep == port || *ep ) {
 891                 /* Not numeric */
 892                 struct servent *se = getservbyname(port,"tcp");
 893                 if ( !se )
 894                         die(_("unknown port %s"), port);
 895                 nport = se->s_port;
 896         }
 897
 898         if (flags & CONNECT_VERBOSE)
 899                 /* TRANSLATORS: this is the end of "Looking up %s ... " */
 900                 fprintf(stderr, _("done.\nConnecting to %s (port %s) ... "), host, port);
 901
 902         for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
 903                 memset(&sa, 0, sizeof sa);
 904                 sa.sin_family = he->h_addrtype;
 905                 sa.sin_port = htons(nport);
 906                 memcpy(&sa.sin_addr, *ap, he->h_length);
 907
 908                 sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 909                 if ((sockfd < 0) ||
 910                     connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 911                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 912                                 host,
 913                                 cnt,
 914                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr),
 915                                 strerror(errno));
 916                         if (0 <= sockfd)
 917                                 close(sockfd);
 918                         sockfd = -1;
 919                         continue;
 920                 }
 921                 if (flags & CONNECT_VERBOSE)
 922                         fprintf(stderr, "%s ",
 923                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr));
 924                 break;
 925         }
 926
 927         if (sockfd < 0)
 928                 die(_("unable to connect to %s:\n%s"), host, error_message.buf);
 929
 930         enable_keepalive(sockfd);
 931
 932         if (flags & CONNECT_VERBOSE)
 933                 /* TRANSLATORS: this is the end of "Connecting to %s (port %s) ... " */
 934                 fprintf_ln(stderr, _("done."));
 935
 936         return sockfd;
 937 }
 938
 939 #endif /* NO_IPV6 */
 940
 941
 942 /*
 943  * Dummy child_process returned by git_connect() if the transport protocol
 944  * does not need fork(2).
 945  */
 946 static struct child_process no_fork = CHILD_PROCESS_INIT;
 947
 948 int git_connection_is_socket(struct child_process *conn)
 949 {
 950         return conn == &no_fork;
 951 }
 952
 953 static struct child_process *git_tcp_connect(int fd[2], char *host, int flags)
 954 {
 955         int sockfd = git_tcp_connect_sock(host, flags);
 956
 957         fd[0] = sockfd;
 958         fd[1] = dup(sockfd);
 959
 960         return &no_fork;
 961 }
 962
 963
 964 static char *git_proxy_command;
 965
 966 static int git_proxy_command_options(const char *var, const char *value,
 967                 void *cb)
 968 {
 969         if (!strcmp(var, "core.gitproxy")) {
 970                 const char *for_pos;
 971                 int matchlen = -1;
 972                 int hostlen;
 973                 const char *rhost_name = cb;
 974                 int rhost_len = strlen(rhost_name);
 975
 976                 if (git_proxy_command)
 977                         return 0;
 978                 if (!value)
 979                         return config_error_nonbool(var);
 980                 /* [core]
 981                  * ;# matches www.kernel.org as well
 982                  * gitproxy = netcatter-1 for kernel.org
 983                  * gitproxy = netcatter-2 for sample.xz
 984                  * gitproxy = netcatter-default
 985                  */
 986                 for_pos = strstr(value, " for ");
 987                 if (!for_pos)
 988                         /* matches everybody */
 989                         matchlen = strlen(value);
 990                 else {
 991                         hostlen = strlen(for_pos + 5);
 992                         if (rhost_len < hostlen)
 993                                 matchlen = -1;
 994                         else if (!strncmp(for_pos + 5,
 995                                           rhost_name + rhost_len - hostlen,
 996                                           hostlen) &&
 997                                  ((rhost_len == hostlen) ||
 998                                   rhost_name[rhost_len - hostlen -1] == '.'))
 999                                 matchlen = for_pos - value;
1000                         else
1001                                 matchlen = -1;
1002                 }
1003                 if (0 <= matchlen) {
1004                         /* core.gitproxy = none for kernel.org */
1005                         if (matchlen == 4 &&
1006                             !memcmp(value, "none", 4))
1007                                 matchlen = 0;
1008                         git_proxy_command = xmemdupz(value, matchlen);
1009                 }
1010                 return 0;
1011         }
1012
1013         return git_default_config(var, value, cb);
1014 }
1015
1016 static int git_use_proxy(const char *host)
1017 {
1018         git_proxy_command = getenv("GIT_PROXY_COMMAND");
1019         git_config(git_proxy_command_options, (void*)host);
1020         return (git_proxy_command && *git_proxy_command);
1021 }
1022
1023 static struct child_process *git_proxy_connect(int fd[2], char *host)
1024 {
1025         const char *port = STR(DEFAULT_GIT_PORT);
1026         struct child_process *proxy;
1027
1028         get_host_and_port(&host, &port);
1029
1030         if (looks_like_command_line_option(host))
1031                 die(_("strange hostname '%s' blocked"), host);
1032         if (looks_like_command_line_option(port))
1033                 die(_("strange port '%s' blocked"), port);
1034
1035         proxy = xmalloc(sizeof(*proxy));
1036         child_process_init(proxy);
1037         strvec_push(&proxy->args, git_proxy_command);
1038         strvec_push(&proxy->args, host);
1039         strvec_push(&proxy->args, port);
1040         proxy->in = -1;
1041         proxy->out = -1;
1042         if (start_command(proxy))
1043                 die(_("cannot start proxy %s"), git_proxy_command);
1044         fd[0] = proxy->out; /* read from proxy stdout */
1045         fd[1] = proxy->in;  /* write to proxy stdin */
1046         return proxy;
1047 }
1048
1049 static char *get_port(char *host)
1050 {
1051         char *end;
1052         char *p = strchr(host, ':');
1053
1054         if (p) {
1055                 long port = strtol(p + 1, &end, 10);
1056                 if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
1057                         *p = '\0';
1058                         return p+1;
1059                 }
1060         }
1061
1062         return NULL;
1063 }
1064
1065 /*
1066  * Extract protocol and relevant parts from the specified connection URL.
1067  * The caller must free() the returned strings.
1068  */
1069 static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
1070                                        char **ret_path)
1071 {
1072         char *url;
1073         char *host, *path;
1074         char *end;
1075         int separator = '/';
1076         enum protocol protocol = PROTO_LOCAL;
1077
1078         if (is_url(url_orig))
1079                 url = url_decode(url_orig);
1080         else
1081                 url = xstrdup(url_orig);
1082
1083         host = strstr(url, "://");
1084         if (host) {
1085                 *host = '\0';
1086                 protocol = get_protocol(url);
1087                 host += 3;
1088         } else {
1089                 host = url;
1090                 if (!url_is_local_not_ssh(url)) {
1091                         protocol = PROTO_SSH;
1092                         separator = ':';
1093                 }
1094         }
1095
1096         /*
1097          * Don't do destructive transforms as protocol code does
1098          * '[]' unwrapping in get_host_and_port()
1099          */
1100         end = host_end(&host, 0);
1101
1102         if (protocol == PROTO_LOCAL)
1103                 path = end;
1104         else if (protocol == PROTO_FILE && *host != '/' &&
1105                  !has_dos_drive_prefix(host) &&
1106                  offset_1st_component(host - 2) > 1)
1107                 path = host - 2; /* include the leading "//" */
1108         else if (protocol == PROTO_FILE && has_dos_drive_prefix(end))
1109                 path = end; /* "file://$(pwd)" may be "file://C:/projects/repo" */
1110         else
1111                 path = strchr(end, separator);
1112
1113         if (!path || !*path)
1114                 die(_("no path specified; see 'git help pull' for valid url syntax"));
1115
1116         /*
1117          * null-terminate hostname and point path to ~ for URL's like this:
1118          *    ssh://host.xz/~user/repo
1119          */
1120
1121         end = path; /* Need to \0 terminate host here */
1122         if (separator == ':')
1123                 path++; /* path starts after ':' */
1124         if (protocol == PROTO_GIT || protocol == PROTO_SSH) {
1125                 if (path[1] == '~')
1126                         path++;
1127         }
1128
1129         path = xstrdup(path);
1130         *end = '\0';
1131
1132         *ret_host = xstrdup(host);
1133         *ret_path = path;
1134         free(url);
1135         return protocol;
1136 }
1137
1138 static const char *get_ssh_command(void)
1139 {
1140         const char *ssh;
1141
1142         if ((ssh = getenv("GIT_SSH_COMMAND")))
1143                 return ssh;
1144
1145         if (!git_config_get_string_tmp("core.sshcommand", &ssh))
1146                 return ssh;
1147
1148         return NULL;
1149 }
1150
1151 enum ssh_variant {
1152         VARIANT_AUTO,
1153         VARIANT_SIMPLE,
1154         VARIANT_SSH,
1155         VARIANT_PLINK,
1156         VARIANT_PUTTY,
1157         VARIANT_TORTOISEPLINK,
1158 };
1159
1160 static void override_ssh_variant(enum ssh_variant *ssh_variant)
1161 {
1162         const char *variant = getenv("GIT_SSH_VARIANT");
1163
1164         if (!variant && git_config_get_string_tmp("ssh.variant", &variant))
1165                 return;
1166
1167         if (!strcmp(variant, "auto"))
1168                 *ssh_variant = VARIANT_AUTO;
1169         else if (!strcmp(variant, "plink"))
1170                 *ssh_variant = VARIANT_PLINK;
1171         else if (!strcmp(variant, "putty"))
1172                 *ssh_variant = VARIANT_PUTTY;
1173         else if (!strcmp(variant, "tortoiseplink"))
1174                 *ssh_variant = VARIANT_TORTOISEPLINK;
1175         else if (!strcmp(variant, "simple"))
1176                 *ssh_variant = VARIANT_SIMPLE;
1177         else
1178                 *ssh_variant = VARIANT_SSH;
1179 }
1180
1181 static enum ssh_variant determine_ssh_variant(const char *ssh_command,
1182                                               int is_cmdline)
1183 {
1184         enum ssh_variant ssh_variant = VARIANT_AUTO;
1185         const char *variant;
1186         char *p = NULL;
1187
1188         override_ssh_variant(&ssh_variant);
1189
1190         if (ssh_variant != VARIANT_AUTO)
1191                 return ssh_variant;
1192
1193         if (!is_cmdline) {
1194                 p = xstrdup(ssh_command);
1195                 variant = basename(p);
1196         } else {
1197                 const char **ssh_argv;
1198
1199                 p = xstrdup(ssh_command);
1200                 if (split_cmdline(p, &ssh_argv) > 0) {
1201                         variant = basename((char *)ssh_argv[0]);
1202                         /*
1203                          * At this point, variant points into the buffer
1204                          * referenced by p, hence we do not need ssh_argv
1205                          * any longer.
1206                          */
1207                         free(ssh_argv);
1208                 } else {
1209                         free(p);
1210                         return ssh_variant;
1211                 }
1212         }
1213
1214         if (!strcasecmp(variant, "ssh") ||
1215             !strcasecmp(variant, "ssh.exe"))
1216                 ssh_variant = VARIANT_SSH;
1217         else if (!strcasecmp(variant, "plink") ||
1218                  !strcasecmp(variant, "plink.exe"))
1219                 ssh_variant = VARIANT_PLINK;
1220         else if (!strcasecmp(variant, "tortoiseplink") ||
1221                  !strcasecmp(variant, "tortoiseplink.exe"))
1222                 ssh_variant = VARIANT_TORTOISEPLINK;
1223
1224         free(p);
1225         return ssh_variant;
1226 }
1227
1228 /*
1229  * Open a connection using Git's native protocol.
1230  *
1231  * The caller is responsible for freeing hostandport, but this function may
1232  * modify it (for example, to truncate it to remove the port part).
1233  */
1234 static struct child_process *git_connect_git(int fd[2], char *hostandport,
1235                                              const char *path, const char *prog,
1236                                              enum protocol_version version,
1237                                              int flags)
1238 {
1239         struct child_process *conn;
1240         struct strbuf request = STRBUF_INIT;
1241         /*
1242          * Set up virtual host information based on where we will
1243          * connect, unless the user has overridden us in
1244          * the environment.
1245          */
1246         char *target_host = getenv("GIT_OVERRIDE_VIRTUAL_HOST");
1247         if (target_host)
1248                 target_host = xstrdup(target_host);
1249         else
1250                 target_host = xstrdup(hostandport);
1251
1252         transport_check_allowed("git");
1253         if (strchr(target_host, '\n') || strchr(path, '\n'))
1254                 die(_("newline is forbidden in git:// hosts and repo paths"));
1255
1256         /*
1257          * These underlying connection commands die() if they
1258          * cannot connect.
1259          */
1260         if (git_use_proxy(hostandport))
1261                 conn = git_proxy_connect(fd, hostandport);
1262         else
1263                 conn = git_tcp_connect(fd, hostandport, flags);
1264         /*
1265          * Separate original protocol components prog and path
1266          * from extended host header with a NUL byte.
1267          *
1268          * Note: Do not add any other headers here!  Doing so
1269          * will cause older git-daemon servers to crash.
1270          */
1271         strbuf_addf(&request,
1272                     "%s %s%chost=%s%c",
1273                     prog, path, 0,
1274                     target_host, 0);
1275
1276         /* If using a new version put that stuff here after a second null byte */
1277         if (version > 0) {
1278                 strbuf_addch(&request, '\0');
1279                 strbuf_addf(&request, "version=%d%c",
1280                             version, '\0');
1281         }
1282
1283         packet_write(fd[1], request.buf, request.len);
1284
1285         free(target_host);
1286         strbuf_release(&request);
1287         return conn;
1288 }
1289
1290 /*
1291  * Append the appropriate environment variables to `env` and options to
1292  * `args` for running ssh in Git's SSH-tunneled transport.
1293  */
1294 static void push_ssh_options(struct strvec *args, struct strvec *env,
1295                              enum ssh_variant variant, const char *port,
1296                              enum protocol_version version, int flags)
1297 {
1298         if (variant == VARIANT_SSH &&
1299             version > 0) {
1300                 strvec_push(args, "-o");
1301                 strvec_push(args, "SendEnv=" GIT_PROTOCOL_ENVIRONMENT);
1302                 strvec_pushf(env, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
1303                              version);
1304         }
1305
1306         if (flags & CONNECT_IPV4) {
1307                 switch (variant) {
1308                 case VARIANT_AUTO:
1309                         BUG("VARIANT_AUTO passed to push_ssh_options");
1310                 case VARIANT_SIMPLE:
1311                         die(_("ssh variant 'simple' does not support -4"));
1312                 case VARIANT_SSH:
1313                 case VARIANT_PLINK:
1314                 case VARIANT_PUTTY:
1315                 case VARIANT_TORTOISEPLINK:
1316                         strvec_push(args, "-4");
1317                 }
1318         } else if (flags & CONNECT_IPV6) {
1319                 switch (variant) {
1320                 case VARIANT_AUTO:
1321                         BUG("VARIANT_AUTO passed to push_ssh_options");
1322                 case VARIANT_SIMPLE:
1323                         die(_("ssh variant 'simple' does not support -6"));
1324                 case VARIANT_SSH:
1325                 case VARIANT_PLINK:
1326                 case VARIANT_PUTTY:
1327                 case VARIANT_TORTOISEPLINK:
1328                         strvec_push(args, "-6");
1329                 }
1330         }
1331
1332         if (variant == VARIANT_TORTOISEPLINK)
1333                 strvec_push(args, "-batch");
1334
1335         if (port) {
1336                 switch (variant) {
1337                 case VARIANT_AUTO:
1338                         BUG("VARIANT_AUTO passed to push_ssh_options");
1339                 case VARIANT_SIMPLE:
1340                         die(_("ssh variant 'simple' does not support setting port"));
1341                 case VARIANT_SSH:
1342                         strvec_push(args, "-p");
1343                         break;
1344                 case VARIANT_PLINK:
1345                 case VARIANT_PUTTY:
1346                 case VARIANT_TORTOISEPLINK:
1347                         strvec_push(args, "-P");
1348                 }
1349
1350                 strvec_push(args, port);
1351         }
1352 }
1353
1354 /* Prepare a child_process for use by Git's SSH-tunneled transport. */
1355 static void fill_ssh_args(struct child_process *conn, const char *ssh_host,
1356                           const char *port, enum protocol_version version,
1357                           int flags)
1358 {
1359         const char *ssh;
1360         enum ssh_variant variant;
1361
1362         if (looks_like_command_line_option(ssh_host))
1363                 die(_("strange hostname '%s' blocked"), ssh_host);
1364
1365         ssh = get_ssh_command();
1366         if (ssh) {
1367                 variant = determine_ssh_variant(ssh, 1);
1368         } else {
1369                 /*
1370                  * GIT_SSH is the no-shell version of
1371                  * GIT_SSH_COMMAND (and must remain so for
1372                  * historical compatibility).
1373                  */
1374                 conn->use_shell = 0;
1375
1376                 ssh = getenv("GIT_SSH");
1377                 if (!ssh)
1378                         ssh = "ssh";
1379                 variant = determine_ssh_variant(ssh, 0);
1380         }
1381
1382         if (variant == VARIANT_AUTO) {
1383                 struct child_process detect = CHILD_PROCESS_INIT;
1384
1385                 detect.use_shell = conn->use_shell;
1386                 detect.no_stdin = detect.no_stdout = detect.no_stderr = 1;
1387
1388                 strvec_push(&detect.args, ssh);
1389                 strvec_push(&detect.args, "-G");
1390                 push_ssh_options(&detect.args, &detect.env,
1391                                  VARIANT_SSH, port, version, flags);
1392                 strvec_push(&detect.args, ssh_host);
1393
1394                 variant = run_command(&detect) ? VARIANT_SIMPLE : VARIANT_SSH;
1395         }
1396
1397         strvec_push(&conn->args, ssh);
1398         push_ssh_options(&conn->args, &conn->env, variant, port, version,
1399                          flags);
1400         strvec_push(&conn->args, ssh_host);
1401 }
1402
1403 /*
1404  * This returns the dummy child_process `no_fork` if the transport protocol
1405  * does not need fork(2), or a struct child_process object if it does.  Once
1406  * done, finish the connection with finish_connect() with the value returned
1407  * from this function (it is safe to call finish_connect() with NULL to
1408  * support the former case).
1409  *
1410  * If it returns, the connect is successful; it just dies on errors (this
1411  * will hopefully be changed in a libification effort, to return NULL when
1412  * the connection failed).
1413  */
1414 struct child_process *git_connect(int fd[2], const char *url,
1415                                   const char *name,
1416                                   const char *prog, int flags)
1417 {
1418         char *hostandport, *path;
1419         struct child_process *conn;
1420         enum protocol protocol;
1421         enum protocol_version version = get_protocol_version_config();
1422
1423         /*
1424          * NEEDSWORK: If we are trying to use protocol v2 and we are planning
1425          * to perform any operation that doesn't involve upload-pack (i.e., a
1426          * fetch, ls-remote, etc), then fallback to v0 since we don't know how
1427          * to do anything else (like push or remote archive) via v2.
1428          */
1429         if (version == protocol_v2 && strcmp("git-upload-pack", name))
1430                 version = protocol_v0;
1431
1432         /* Without this we cannot rely on waitpid() to tell
1433          * what happened to our children.
1434          */
1435         signal(SIGCHLD, SIG_DFL);
1436
1437         protocol = parse_connect_url(url, &hostandport, &path);
1438         if ((flags & CONNECT_DIAG_URL) && (protocol != PROTO_SSH)) {
1439                 printf("Diag: url=%s\n", url ? url : "NULL");
1440                 printf("Diag: protocol=%s\n", prot_name(protocol));
1441                 printf("Diag: hostandport=%s\n", hostandport ? hostandport : "NULL");
1442                 printf("Diag: path=%s\n", path ? path : "NULL");
1443                 conn = NULL;
1444         } else if (protocol == PROTO_GIT) {
1445                 conn = git_connect_git(fd, hostandport, path, prog, version, flags);
1446                 conn->trace2_child_class = "transport/git";
1447         } else {
1448                 struct strbuf cmd = STRBUF_INIT;
1449                 const char *const *var;
1450
1451                 conn = xmalloc(sizeof(*conn));
1452                 child_process_init(conn);
1453
1454                 if (looks_like_command_line_option(path))
1455                         die(_("strange pathname '%s' blocked"), path);
1456
1457                 strbuf_addstr(&cmd, prog);
1458                 strbuf_addch(&cmd, ' ');
1459                 sq_quote_buf(&cmd, path);
1460
1461                 /* remove repo-local variables from the environment */
1462                 for (var = local_repo_env; *var; var++)
1463                         strvec_push(&conn->env, *var);
1464
1465                 conn->use_shell = 1;
1466                 conn->in = conn->out = -1;
1467                 if (protocol == PROTO_SSH) {
1468                         char *ssh_host = hostandport;
1469                         const char *port = NULL;
1470                         transport_check_allowed("ssh");
1471                         get_host_and_port(&ssh_host, &port);
1472
1473                         if (!port)
1474                                 port = get_port(ssh_host);
1475
1476                         if (flags & CONNECT_DIAG_URL) {
1477                                 printf("Diag: url=%s\n", url ? url : "NULL");
1478                                 printf("Diag: protocol=%s\n", prot_name(protocol));
1479                                 printf("Diag: userandhost=%s\n", ssh_host ? ssh_host : "NULL");
1480                                 printf("Diag: port=%s\n", port ? port : "NONE");
1481                                 printf("Diag: path=%s\n", path ? path : "NULL");
1482
1483                                 free(hostandport);
1484                                 free(path);
1485                                 free(conn);
1486                                 strbuf_release(&cmd);
1487                                 return NULL;
1488                         }
1489                         conn->trace2_child_class = "transport/ssh";
1490                         fill_ssh_args(conn, ssh_host, port, version, flags);
1491                 } else {
1492                         transport_check_allowed("file");
1493                         conn->trace2_child_class = "transport/file";
1494                         if (version > 0) {
1495                                 strvec_pushf(&conn->env,
1496                                              GIT_PROTOCOL_ENVIRONMENT "=version=%d",
1497                                              version);
1498                         }
1499                 }
1500                 strvec_push(&conn->args, cmd.buf);
1501
1502                 if (start_command(conn))
1503                         die(_("unable to fork"));
1504
1505                 fd[0] = conn->out; /* read from child's stdout */
1506                 fd[1] = conn->in;  /* write to child's stdin */
1507                 strbuf_release(&cmd);
1508         }
1509         free(hostandport);
1510         free(path);
1511         return conn;
1512 }
1513
1514 int finish_connect(struct child_process *conn)
1515 {
1516         int code;
1517         if (!conn || git_connection_is_socket(conn))
1518                 return 0;
1519
1520         code = finish_command(conn);
1521         free(conn);
1522         return code;
1523 }