git.oblomov.eu Git - git/blob - connect.c

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