connect.c

   1 #include "git-compat-util.h"
   2 #include "cache.h"
   3 #include "config.h"
   4 #include "pkt-line.h"
   5 #include "quote.h"
   6 #include "refs.h"
   7 #include "run-command.h"
   8 #include "remote.h"
   9 #include "connect.h"
  10 #include "url.h"
  11 #include "string-list.h"
  12 #include "sha1-array.h"
  13 #include "transport.h"
  14 #include "strbuf.h"
  15 #include "version.h"
  16 #include "protocol.h"
  17
  18 static char *server_capabilities_v1;
  19 static struct argv_array server_capabilities_v2 = ARGV_ARRAY_INIT;
  20 static const char *parse_feature_value(const char *, const char *, int *);
  21
  22 static int check_ref(const char *name, unsigned int flags)
  23 {
  24         if (!flags)
  25                 return 1;
  26
  27         if (!skip_prefix(name, "refs/", &name))
  28                 return 0;
  29
  30         /* REF_NORMAL means that we don't want the magic fake tag refs */
  31         if ((flags & REF_NORMAL) && check_refname_format(name, 0))
  32                 return 0;
  33
  34         /* REF_HEADS means that we want regular branch heads */
  35         if ((flags & REF_HEADS) && starts_with(name, "heads/"))
  36                 return 1;
  37
  38         /* REF_TAGS means that we want tags */
  39         if ((flags & REF_TAGS) && starts_with(name, "tags/"))
  40                 return 1;
  41
  42         /* All type bits clear means that we are ok with anything */
  43         return !(flags & ~REF_NORMAL);
  44 }
  45
  46 int check_ref_type(const struct ref *ref, int flags)
  47 {
  48         return check_ref(ref->name, flags);
  49 }
  50
  51 static void die_initial_contact(int unexpected)
  52 {
  53         /*
  54          * A hang-up after seeing some response from the other end
  55          * means that it is unexpected, as we know the other end is
  56          * willing to talk to us.  A hang-up before seeing any
  57          * response does not necessarily mean an ACL problem, though.
  58          */
  59         if (unexpected)
  60                 die(_("The remote end hung up upon initial contact"));
  61         else
  62                 die(_("Could not read from remote repository.\n\n"
  63                       "Please make sure you have the correct access rights\n"
  64                       "and the repository exists."));
  65 }
  66
  67 /* Checks if the server supports the capability 'c' */
  68 int server_supports_v2(const char *c, int die_on_error)
  69 {
  70         int i;
  71
  72         for (i = 0; i < server_capabilities_v2.argc; i++) {
  73                 const char *out;
  74                 if (skip_prefix(server_capabilities_v2.argv[i], c, &out) &&
  75                     (!*out || *out == '='))
  76                         return 1;
  77         }
  78
  79         if (die_on_error)
  80                 die("server doesn't support '%s'", c);
  81
  82         return 0;
  83 }
  84
  85 int server_supports_feature(const char *c, const char *feature,
  86                             int die_on_error)
  87 {
  88         int i;
  89
  90         for (i = 0; i < server_capabilities_v2.argc; i++) {
  91                 const char *out;
  92                 if (skip_prefix(server_capabilities_v2.argv[i], c, &out) &&
  93                     (!*out || *(out++) == '=')) {
  94                         if (parse_feature_request(out, feature))
  95                                 return 1;
  96                         else
  97                                 break;
  98                 }
  99         }
 100
 101         if (die_on_error)
 102                 die("server doesn't support feature '%s'", feature);
 103
 104         return 0;
 105 }
 106
 107 static void process_capabilities_v2(struct packet_reader *reader)
 108 {
 109         while (packet_reader_read(reader) == PACKET_READ_NORMAL)
 110                 argv_array_push(&server_capabilities_v2, reader->line);
 111
 112         if (reader->status != PACKET_READ_FLUSH)
 113                 die("expected flush after capabilities");
 114 }
 115
 116 enum protocol_version discover_version(struct packet_reader *reader)
 117 {
 118         enum protocol_version version = protocol_unknown_version;
 119
 120         /*
 121          * Peek the first line of the server's response to
 122          * determine the protocol version the server is speaking.
 123          */
 124         switch (packet_reader_peek(reader)) {
 125         case PACKET_READ_EOF:
 126                 die_initial_contact(0);
 127         case PACKET_READ_FLUSH:
 128         case PACKET_READ_DELIM:
 129                 version = protocol_v0;
 130                 break;
 131         case PACKET_READ_NORMAL:
 132                 version = determine_protocol_version_client(reader->line);
 133                 break;
 134         }
 135
 136         switch (version) {
 137         case protocol_v2:
 138                 process_capabilities_v2(reader);
 139                 break;
 140         case protocol_v1:
 141                 /* Read the peeked version line */
 142                 packet_reader_read(reader);
 143                 break;
 144         case protocol_v0:
 145                 break;
 146         case protocol_unknown_version:
 147                 BUG("unknown protocol version");
 148         }
 149
 150         return version;
 151 }
 152
 153 static void parse_one_symref_info(struct string_list *symref, const char *val, int len)
 154 {
 155         char *sym, *target;
 156         struct string_list_item *item;
 157
 158         if (!len)
 159                 return; /* just "symref" */
 160         /* e.g. "symref=HEAD:refs/heads/master" */
 161         sym = xmemdupz(val, len);
 162         target = strchr(sym, ':');
 163         if (!target)
 164                 /* just "symref=something" */
 165                 goto reject;
 166         *(target++) = '\0';
 167         if (check_refname_format(sym, REFNAME_ALLOW_ONELEVEL) ||
 168             check_refname_format(target, REFNAME_ALLOW_ONELEVEL))
 169                 /* "symref=bogus:pair */
 170                 goto reject;
 171         item = string_list_append_nodup(symref, sym);
 172         item->util = target;
 173         return;
 174 reject:
 175         free(sym);
 176         return;
 177 }
 178
 179 static void annotate_refs_with_symref_info(struct ref *ref)
 180 {
 181         struct string_list symref = STRING_LIST_INIT_DUP;
 182         const char *feature_list = server_capabilities_v1;
 183
 184         while (feature_list) {
 185                 int len;
 186                 const char *val;
 187
 188                 val = parse_feature_value(feature_list, "symref", &len);
 189                 if (!val)
 190                         break;
 191                 parse_one_symref_info(&symref, val, len);
 192                 feature_list = val + 1;
 193         }
 194         string_list_sort(&symref);
 195
 196         for (; ref; ref = ref->next) {
 197                 struct string_list_item *item;
 198                 item = string_list_lookup(&symref, ref->name);
 199                 if (!item)
 200                         continue;
 201                 ref->symref = xstrdup((char *)item->util);
 202         }
 203         string_list_clear(&symref, 0);
 204 }
 205
 206 static void process_capabilities(const char *line, int *len)
 207 {
 208         int nul_location = strlen(line);
 209         if (nul_location == *len)
 210                 return;
 211         server_capabilities_v1 = xstrdup(line + nul_location + 1);
 212         *len = nul_location;
 213 }
 214
 215 static int process_dummy_ref(const char *line)
 216 {
 217         struct object_id oid;
 218         const char *name;
 219
 220         if (parse_oid_hex(line, &oid, &name))
 221                 return 0;
 222         if (*name != ' ')
 223                 return 0;
 224         name++;
 225
 226         return !oidcmp(&null_oid, &oid) && !strcmp(name, "capabilities^{}");
 227 }
 228
 229 static void check_no_capabilities(const char *line, int len)
 230 {
 231         if (strlen(line) != len)
 232                 warning("Ignoring capabilities after first line '%s'",
 233                         line + strlen(line));
 234 }
 235
 236 static int process_ref(const char *line, int len, struct ref ***list,
 237                        unsigned int flags, struct oid_array *extra_have)
 238 {
 239         struct object_id old_oid;
 240         const char *name;
 241
 242         if (parse_oid_hex(line, &old_oid, &name))
 243                 return 0;
 244         if (*name != ' ')
 245                 return 0;
 246         name++;
 247
 248         if (extra_have && !strcmp(name, ".have")) {
 249                 oid_array_append(extra_have, &old_oid);
 250         } else if (!strcmp(name, "capabilities^{}")) {
 251                 die("protocol error: unexpected capabilities^{}");
 252         } else if (check_ref(name, flags)) {
 253                 struct ref *ref = alloc_ref(name);
 254                 oidcpy(&ref->old_oid, &old_oid);
 255                 **list = ref;
 256                 *list = &ref->next;
 257         }
 258         check_no_capabilities(line, len);
 259         return 1;
 260 }
 261
 262 static int process_shallow(const char *line, int len,
 263                            struct oid_array *shallow_points)
 264 {
 265         const char *arg;
 266         struct object_id old_oid;
 267
 268         if (!skip_prefix(line, "shallow ", &arg))
 269                 return 0;
 270
 271         if (get_oid_hex(arg, &old_oid))
 272                 die("protocol error: expected shallow sha-1, got '%s'", arg);
 273         if (!shallow_points)
 274                 die("repository on the other end cannot be shallow");
 275         oid_array_append(shallow_points, &old_oid);
 276         check_no_capabilities(line, len);
 277         return 1;
 278 }
 279
 280 enum get_remote_heads_state {
 281         EXPECTING_FIRST_REF = 0,
 282         EXPECTING_REF,
 283         EXPECTING_SHALLOW,
 284         EXPECTING_DONE,
 285 };
 286
 287 /*
 288  * Read all the refs from the other end
 289  */
 290 struct ref **get_remote_heads(struct packet_reader *reader,
 291                               struct ref **list, unsigned int flags,
 292                               struct oid_array *extra_have,
 293                               struct oid_array *shallow_points)
 294 {
 295         struct ref **orig_list = list;
 296         int len = 0;
 297         enum get_remote_heads_state state = EXPECTING_FIRST_REF;
 298         const char *arg;
 299
 300         *list = NULL;
 301
 302         while (state != EXPECTING_DONE) {
 303                 switch (packet_reader_read(reader)) {
 304                 case PACKET_READ_EOF:
 305                         die_initial_contact(1);
 306                 case PACKET_READ_NORMAL:
 307                         len = reader->pktlen;
 308                         if (len > 4 && skip_prefix(reader->line, "ERR ", &arg))
 309                                 die("remote error: %s", arg);
 310                         break;
 311                 case PACKET_READ_FLUSH:
 312                         state = EXPECTING_DONE;
 313                         break;
 314                 case PACKET_READ_DELIM:
 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 struct ref **get_remote_refs(int fd_out, struct packet_reader *reader,
 410                              struct ref **list, int for_push,
 411                              const struct argv_array *ref_prefixes)
 412 {
 413         int i;
 414         *list = NULL;
 415
 416         if (server_supports_v2("ls-refs", 1))
 417                 packet_write_fmt(fd_out, "command=ls-refs\n");
 418
 419         if (server_supports_v2("agent", 0))
 420                 packet_write_fmt(fd_out, "agent=%s", git_user_agent_sanitized());
 421
 422         packet_delim(fd_out);
 423         /* When pushing we don't want to request the peeled tags */
 424         if (!for_push)
 425                 packet_write_fmt(fd_out, "peel\n");
 426         packet_write_fmt(fd_out, "symrefs\n");
 427         for (i = 0; ref_prefixes && i < ref_prefixes->argc; i++) {
 428                 packet_write_fmt(fd_out, "ref-prefix %s\n",
 429                                  ref_prefixes->argv[i]);
 430         }
 431         packet_flush(fd_out);
 432
 433         /* Process response from server */
 434         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
 435                 if (!process_ref_v2(reader->line, &list))
 436                         die("invalid ls-refs response: %s", reader->line);
 437         }
 438
 439         if (reader->status != PACKET_READ_FLUSH)
 440                 die("expected flush after ref listing");
 441
 442         return list;
 443 }
 444
 445 static const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
 446 {
 447         int len;
 448
 449         if (!feature_list)
 450                 return NULL;
 451
 452         len = strlen(feature);
 453         while (*feature_list) {
 454                 const char *found = strstr(feature_list, feature);
 455                 if (!found)
 456                         return NULL;
 457                 if (feature_list == found || isspace(found[-1])) {
 458                         const char *value = found + len;
 459                         /* feature with no value (e.g., "thin-pack") */
 460                         if (!*value || isspace(*value)) {
 461                                 if (lenp)
 462                                         *lenp = 0;
 463                                 return value;
 464                         }
 465                         /* feature with a value (e.g., "agent=git/1.2.3") */
 466                         else if (*value == '=') {
 467                                 value++;
 468                                 if (lenp)
 469                                         *lenp = strcspn(value, " \t\n");
 470                                 return value;
 471                         }
 472                         /*
 473                          * otherwise we matched a substring of another feature;
 474                          * keep looking
 475                          */
 476                 }
 477                 feature_list = found + 1;
 478         }
 479         return NULL;
 480 }
 481
 482 int parse_feature_request(const char *feature_list, const char *feature)
 483 {
 484         return !!parse_feature_value(feature_list, feature, NULL);
 485 }
 486
 487 const char *server_feature_value(const char *feature, int *len)
 488 {
 489         return parse_feature_value(server_capabilities_v1, feature, len);
 490 }
 491
 492 int server_supports(const char *feature)
 493 {
 494         return !!server_feature_value(feature, NULL);
 495 }
 496
 497 enum protocol {
 498         PROTO_LOCAL = 1,
 499         PROTO_FILE,
 500         PROTO_SSH,
 501         PROTO_GIT
 502 };
 503
 504 int url_is_local_not_ssh(const char *url)
 505 {
 506         const char *colon = strchr(url, ':');
 507         const char *slash = strchr(url, '/');
 508         return !colon || (slash && slash < colon) ||
 509                 has_dos_drive_prefix(url);
 510 }
 511
 512 static const char *prot_name(enum protocol protocol)
 513 {
 514         switch (protocol) {
 515                 case PROTO_LOCAL:
 516                 case PROTO_FILE:
 517                         return "file";
 518                 case PROTO_SSH:
 519                         return "ssh";
 520                 case PROTO_GIT:
 521                         return "git";
 522                 default:
 523                         return "unknown protocol";
 524         }
 525 }
 526
 527 static enum protocol get_protocol(const char *name)
 528 {
 529         if (!strcmp(name, "ssh"))
 530                 return PROTO_SSH;
 531         if (!strcmp(name, "git"))
 532                 return PROTO_GIT;
 533         if (!strcmp(name, "git+ssh")) /* deprecated - do not use */
 534                 return PROTO_SSH;
 535         if (!strcmp(name, "ssh+git")) /* deprecated - do not use */
 536                 return PROTO_SSH;
 537         if (!strcmp(name, "file"))
 538                 return PROTO_FILE;
 539         die("I don't handle protocol '%s'", name);
 540 }
 541
 542 static char *host_end(char **hoststart, int removebrackets)
 543 {
 544         char *host = *hoststart;
 545         char *end;
 546         char *start = strstr(host, "@[");
 547         if (start)
 548                 start++; /* Jump over '@' */
 549         else
 550                 start = host;
 551         if (start[0] == '[') {
 552                 end = strchr(start + 1, ']');
 553                 if (end) {
 554                         if (removebrackets) {
 555                                 *end = 0;
 556                                 memmove(start, start + 1, end - start);
 557                                 end++;
 558                         }
 559                 } else
 560                         end = host;
 561         } else
 562                 end = host;
 563         return end;
 564 }
 565
 566 #define STR_(s) # s
 567 #define STR(s)  STR_(s)
 568
 569 static void get_host_and_port(char **host, const char **port)
 570 {
 571         char *colon, *end;
 572         end = host_end(host, 1);
 573         colon = strchr(end, ':');
 574         if (colon) {
 575                 long portnr = strtol(colon + 1, &end, 10);
 576                 if (end != colon + 1 && *end == '\0' && 0 <= portnr && portnr < 65536) {
 577                         *colon = 0;
 578                         *port = colon + 1;
 579                 } else if (!colon[1]) {
 580                         *colon = 0;
 581                 }
 582         }
 583 }
 584
 585 static void enable_keepalive(int sockfd)
 586 {
 587         int ka = 1;
 588
 589         if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
 590                 fprintf(stderr, "unable to set SO_KEEPALIVE on socket: %s\n",
 591                         strerror(errno));
 592 }
 593
 594 #ifndef NO_IPV6
 595
 596 static const char *ai_name(const struct addrinfo *ai)
 597 {
 598         static char addr[NI_MAXHOST];
 599         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
 600                         NI_NUMERICHOST) != 0)
 601                 xsnprintf(addr, sizeof(addr), "(unknown)");
 602
 603         return addr;
 604 }
 605
 606 /*
 607  * Returns a connected socket() fd, or else die()s.
 608  */
 609 static int git_tcp_connect_sock(char *host, int flags)
 610 {
 611         struct strbuf error_message = STRBUF_INIT;
 612         int sockfd = -1;
 613         const char *port = STR(DEFAULT_GIT_PORT);
 614         struct addrinfo hints, *ai0, *ai;
 615         int gai;
 616         int cnt = 0;
 617
 618         get_host_and_port(&host, &port);
 619         if (!*port)
 620                 port = "<none>";
 621
 622         memset(&hints, 0, sizeof(hints));
 623         if (flags & CONNECT_IPV4)
 624                 hints.ai_family = AF_INET;
 625         else if (flags & CONNECT_IPV6)
 626                 hints.ai_family = AF_INET6;
 627         hints.ai_socktype = SOCK_STREAM;
 628         hints.ai_protocol = IPPROTO_TCP;
 629
 630         if (flags & CONNECT_VERBOSE)
 631                 fprintf(stderr, "Looking up %s ... ", host);
 632
 633         gai = getaddrinfo(host, port, &hints, &ai);
 634         if (gai)
 635                 die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
 636
 637         if (flags & CONNECT_VERBOSE)
 638                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 639
 640         for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
 641                 sockfd = socket(ai->ai_family,
 642                                 ai->ai_socktype, ai->ai_protocol);
 643                 if ((sockfd < 0) ||
 644                     (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
 645                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 646                                     host, cnt, ai_name(ai), strerror(errno));
 647                         if (0 <= sockfd)
 648                                 close(sockfd);
 649                         sockfd = -1;
 650                         continue;
 651                 }
 652                 if (flags & CONNECT_VERBOSE)
 653                         fprintf(stderr, "%s ", ai_name(ai));
 654                 break;
 655         }
 656
 657         freeaddrinfo(ai0);
 658
 659         if (sockfd < 0)
 660                 die("unable to connect to %s:\n%s", host, error_message.buf);
 661
 662         enable_keepalive(sockfd);
 663
 664         if (flags & CONNECT_VERBOSE)
 665                 fprintf(stderr, "done.\n");
 666
 667         strbuf_release(&error_message);
 668
 669         return sockfd;
 670 }
 671
 672 #else /* NO_IPV6 */
 673
 674 /*
 675  * Returns a connected socket() fd, or else die()s.
 676  */
 677 static int git_tcp_connect_sock(char *host, int flags)
 678 {
 679         struct strbuf error_message = STRBUF_INIT;
 680         int sockfd = -1;
 681         const char *port = STR(DEFAULT_GIT_PORT);
 682         char *ep;
 683         struct hostent *he;
 684         struct sockaddr_in sa;
 685         char **ap;
 686         unsigned int nport;
 687         int cnt;
 688
 689         get_host_and_port(&host, &port);
 690
 691         if (flags & CONNECT_VERBOSE)
 692                 fprintf(stderr, "Looking up %s ... ", host);
 693
 694         he = gethostbyname(host);
 695         if (!he)
 696                 die("Unable to look up %s (%s)", host, hstrerror(h_errno));
 697         nport = strtoul(port, &ep, 10);
 698         if ( ep == port || *ep ) {
 699                 /* Not numeric */
 700                 struct servent *se = getservbyname(port,"tcp");
 701                 if ( !se )
 702                         die("Unknown port %s", port);
 703                 nport = se->s_port;
 704         }
 705
 706         if (flags & CONNECT_VERBOSE)
 707                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 708
 709         for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
 710                 memset(&sa, 0, sizeof sa);
 711                 sa.sin_family = he->h_addrtype;
 712                 sa.sin_port = htons(nport);
 713                 memcpy(&sa.sin_addr, *ap, he->h_length);
 714
 715                 sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 716                 if ((sockfd < 0) ||
 717                     connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 718                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 719                                 host,
 720                                 cnt,
 721                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr),
 722                                 strerror(errno));
 723                         if (0 <= sockfd)
 724                                 close(sockfd);
 725                         sockfd = -1;
 726                         continue;
 727                 }
 728                 if (flags & CONNECT_VERBOSE)
 729                         fprintf(stderr, "%s ",
 730                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr));
 731                 break;
 732         }
 733
 734         if (sockfd < 0)
 735                 die("unable to connect to %s:\n%s", host, error_message.buf);
 736
 737         enable_keepalive(sockfd);
 738
 739         if (flags & CONNECT_VERBOSE)
 740                 fprintf(stderr, "done.\n");
 741
 742         return sockfd;
 743 }
 744
 745 #endif /* NO_IPV6 */
 746
 747
 748 /*
 749  * Dummy child_process returned by git_connect() if the transport protocol
 750  * does not need fork(2).
 751  */
 752 static struct child_process no_fork = CHILD_PROCESS_INIT;
 753
 754 int git_connection_is_socket(struct child_process *conn)
 755 {
 756         return conn == &no_fork;
 757 }
 758
 759 static struct child_process *git_tcp_connect(int fd[2], char *host, int flags)
 760 {
 761         int sockfd = git_tcp_connect_sock(host, flags);
 762
 763         fd[0] = sockfd;
 764         fd[1] = dup(sockfd);
 765
 766         return &no_fork;
 767 }
 768
 769
 770 static char *git_proxy_command;
 771
 772 static int git_proxy_command_options(const char *var, const char *value,
 773                 void *cb)
 774 {
 775         if (!strcmp(var, "core.gitproxy")) {
 776                 const char *for_pos;
 777                 int matchlen = -1;
 778                 int hostlen;
 779                 const char *rhost_name = cb;
 780                 int rhost_len = strlen(rhost_name);
 781
 782                 if (git_proxy_command)
 783                         return 0;
 784                 if (!value)
 785                         return config_error_nonbool(var);
 786                 /* [core]
 787                  * ;# matches www.kernel.org as well
 788                  * gitproxy = netcatter-1 for kernel.org
 789                  * gitproxy = netcatter-2 for sample.xz
 790                  * gitproxy = netcatter-default
 791                  */
 792                 for_pos = strstr(value, " for ");
 793                 if (!for_pos)
 794                         /* matches everybody */
 795                         matchlen = strlen(value);
 796                 else {
 797                         hostlen = strlen(for_pos + 5);
 798                         if (rhost_len < hostlen)
 799                                 matchlen = -1;
 800                         else if (!strncmp(for_pos + 5,
 801                                           rhost_name + rhost_len - hostlen,
 802                                           hostlen) &&
 803                                  ((rhost_len == hostlen) ||
 804                                   rhost_name[rhost_len - hostlen -1] == '.'))
 805                                 matchlen = for_pos - value;
 806                         else
 807                                 matchlen = -1;
 808                 }
 809                 if (0 <= matchlen) {
 810                         /* core.gitproxy = none for kernel.org */
 811                         if (matchlen == 4 &&
 812                             !memcmp(value, "none", 4))
 813                                 matchlen = 0;
 814                         git_proxy_command = xmemdupz(value, matchlen);
 815                 }
 816                 return 0;
 817         }
 818
 819         return git_default_config(var, value, cb);
 820 }
 821
 822 static int git_use_proxy(const char *host)
 823 {
 824         git_proxy_command = getenv("GIT_PROXY_COMMAND");
 825         git_config(git_proxy_command_options, (void*)host);
 826         return (git_proxy_command && *git_proxy_command);
 827 }
 828
 829 static struct child_process *git_proxy_connect(int fd[2], char *host)
 830 {
 831         const char *port = STR(DEFAULT_GIT_PORT);
 832         struct child_process *proxy;
 833
 834         get_host_and_port(&host, &port);
 835
 836         if (looks_like_command_line_option(host))
 837                 die("strange hostname '%s' blocked", host);
 838         if (looks_like_command_line_option(port))
 839                 die("strange port '%s' blocked", port);
 840
 841         proxy = xmalloc(sizeof(*proxy));
 842         child_process_init(proxy);
 843         argv_array_push(&proxy->args, git_proxy_command);
 844         argv_array_push(&proxy->args, host);
 845         argv_array_push(&proxy->args, port);
 846         proxy->in = -1;
 847         proxy->out = -1;
 848         if (start_command(proxy))
 849                 die("cannot start proxy %s", git_proxy_command);
 850         fd[0] = proxy->out; /* read from proxy stdout */
 851         fd[1] = proxy->in;  /* write to proxy stdin */
 852         return proxy;
 853 }
 854
 855 static char *get_port(char *host)
 856 {
 857         char *end;
 858         char *p = strchr(host, ':');
 859
 860         if (p) {
 861                 long port = strtol(p + 1, &end, 10);
 862                 if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
 863                         *p = '\0';
 864                         return p+1;
 865                 }
 866         }
 867
 868         return NULL;
 869 }
 870
 871 /*
 872  * Extract protocol and relevant parts from the specified connection URL.
 873  * The caller must free() the returned strings.
 874  */
 875 static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
 876                                        char **ret_path)
 877 {
 878         char *url;
 879         char *host, *path;
 880         char *end;
 881         int separator = '/';
 882         enum protocol protocol = PROTO_LOCAL;
 883
 884         if (is_url(url_orig))
 885                 url = url_decode(url_orig);
 886         else
 887                 url = xstrdup(url_orig);
 888
 889         host = strstr(url, "://");
 890         if (host) {
 891                 *host = '\0';
 892                 protocol = get_protocol(url);
 893                 host += 3;
 894         } else {
 895                 host = url;
 896                 if (!url_is_local_not_ssh(url)) {
 897                         protocol = PROTO_SSH;
 898                         separator = ':';
 899                 }
 900         }
 901
 902         /*
 903          * Don't do destructive transforms as protocol code does
 904          * '[]' unwrapping in get_host_and_port()
 905          */
 906         end = host_end(&host, 0);
 907
 908         if (protocol == PROTO_LOCAL)
 909                 path = end;
 910         else if (protocol == PROTO_FILE && has_dos_drive_prefix(end))
 911                 path = end; /* "file://$(pwd)" may be "file://C:/projects/repo" */
 912         else
 913                 path = strchr(end, separator);
 914
 915         if (!path || !*path)
 916                 die("No path specified. See 'man git-pull' for valid url syntax");
 917
 918         /*
 919          * null-terminate hostname and point path to ~ for URL's like this:
 920          *    ssh://host.xz/~user/repo
 921          */
 922
 923         end = path; /* Need to \0 terminate host here */
 924         if (separator == ':')
 925                 path++; /* path starts after ':' */
 926         if (protocol == PROTO_GIT || protocol == PROTO_SSH) {
 927                 if (path[1] == '~')
 928                         path++;
 929         }
 930
 931         path = xstrdup(path);
 932         *end = '\0';
 933
 934         *ret_host = xstrdup(host);
 935         *ret_path = path;
 936         free(url);
 937         return protocol;
 938 }
 939
 940 static const char *get_ssh_command(void)
 941 {
 942         const char *ssh;
 943
 944         if ((ssh = getenv("GIT_SSH_COMMAND")))
 945                 return ssh;
 946
 947         if (!git_config_get_string_const("core.sshcommand", &ssh))
 948                 return ssh;
 949
 950         return NULL;
 951 }
 952
 953 enum ssh_variant {
 954         VARIANT_AUTO,
 955         VARIANT_SIMPLE,
 956         VARIANT_SSH,
 957         VARIANT_PLINK,
 958         VARIANT_PUTTY,
 959         VARIANT_TORTOISEPLINK,
 960 };
 961
 962 static void override_ssh_variant(enum ssh_variant *ssh_variant)
 963 {
 964         const char *variant = getenv("GIT_SSH_VARIANT");
 965
 966         if (!variant && git_config_get_string_const("ssh.variant", &variant))
 967                 return;
 968
 969         if (!strcmp(variant, "auto"))
 970                 *ssh_variant = VARIANT_AUTO;
 971         else if (!strcmp(variant, "plink"))
 972                 *ssh_variant = VARIANT_PLINK;
 973         else if (!strcmp(variant, "putty"))
 974                 *ssh_variant = VARIANT_PUTTY;
 975         else if (!strcmp(variant, "tortoiseplink"))
 976                 *ssh_variant = VARIANT_TORTOISEPLINK;
 977         else if (!strcmp(variant, "simple"))
 978                 *ssh_variant = VARIANT_SIMPLE;
 979         else
 980                 *ssh_variant = VARIANT_SSH;
 981 }
 982
 983 static enum ssh_variant determine_ssh_variant(const char *ssh_command,
 984                                               int is_cmdline)
 985 {
 986         enum ssh_variant ssh_variant = VARIANT_AUTO;
 987         const char *variant;
 988         char *p = NULL;
 989
 990         override_ssh_variant(&ssh_variant);
 991
 992         if (ssh_variant != VARIANT_AUTO)
 993                 return ssh_variant;
 994
 995         if (!is_cmdline) {
 996                 p = xstrdup(ssh_command);
 997                 variant = basename(p);
 998         } else {
 999                 const char **ssh_argv;
1000
1001                 p = xstrdup(ssh_command);
1002                 if (split_cmdline(p, &ssh_argv) > 0) {
1003                         variant = basename((char *)ssh_argv[0]);
1004                         /*
1005                          * At this point, variant points into the buffer
1006                          * referenced by p, hence we do not need ssh_argv
1007                          * any longer.
1008                          */
1009                         free(ssh_argv);
1010                 } else {
1011                         free(p);
1012                         return ssh_variant;
1013                 }
1014         }
1015
1016         if (!strcasecmp(variant, "ssh") ||
1017             !strcasecmp(variant, "ssh.exe"))
1018                 ssh_variant = VARIANT_SSH;
1019         else if (!strcasecmp(variant, "plink") ||
1020                  !strcasecmp(variant, "plink.exe"))
1021                 ssh_variant = VARIANT_PLINK;
1022         else if (!strcasecmp(variant, "tortoiseplink") ||
1023                  !strcasecmp(variant, "tortoiseplink.exe"))
1024                 ssh_variant = VARIANT_TORTOISEPLINK;
1025
1026         free(p);
1027         return ssh_variant;
1028 }
1029
1030 /*
1031  * Open a connection using Git's native protocol.
1032  *
1033  * The caller is responsible for freeing hostandport, but this function may
1034  * modify it (for example, to truncate it to remove the port part).
1035  */
1036 static struct child_process *git_connect_git(int fd[2], char *hostandport,
1037                                              const char *path, const char *prog,
1038                                              enum protocol_version version,
1039                                              int flags)
1040 {
1041         struct child_process *conn;
1042         struct strbuf request = STRBUF_INIT;
1043         /*
1044          * Set up virtual host information based on where we will
1045          * connect, unless the user has overridden us in
1046          * the environment.
1047          */
1048         char *target_host = getenv("GIT_OVERRIDE_VIRTUAL_HOST");
1049         if (target_host)
1050                 target_host = xstrdup(target_host);
1051         else
1052                 target_host = xstrdup(hostandport);
1053
1054         transport_check_allowed("git");
1055
1056         /*
1057          * These underlying connection commands die() if they
1058          * cannot connect.
1059          */
1060         if (git_use_proxy(hostandport))
1061                 conn = git_proxy_connect(fd, hostandport);
1062         else
1063                 conn = git_tcp_connect(fd, hostandport, flags);
1064         /*
1065          * Separate original protocol components prog and path
1066          * from extended host header with a NUL byte.
1067          *
1068          * Note: Do not add any other headers here!  Doing so
1069          * will cause older git-daemon servers to crash.
1070          */
1071         strbuf_addf(&request,
1072                     "%s %s%chost=%s%c",
1073                     prog, path, 0,
1074                     target_host, 0);
1075
1076         /* If using a new version put that stuff here after a second null byte */
1077         if (version > 0) {
1078                 strbuf_addch(&request, '\0');
1079                 strbuf_addf(&request, "version=%d%c",
1080                             version, '\0');
1081         }
1082
1083         packet_write(fd[1], request.buf, request.len);
1084
1085         free(target_host);
1086         strbuf_release(&request);
1087         return conn;
1088 }
1089
1090 /*
1091  * Append the appropriate environment variables to `env` and options to
1092  * `args` for running ssh in Git's SSH-tunneled transport.
1093  */
1094 static void push_ssh_options(struct argv_array *args, struct argv_array *env,
1095                              enum ssh_variant variant, const char *port,
1096                              enum protocol_version version, int flags)
1097 {
1098         if (variant == VARIANT_SSH &&
1099             version > 0) {
1100                 argv_array_push(args, "-o");
1101                 argv_array_push(args, "SendEnv=" GIT_PROTOCOL_ENVIRONMENT);
1102                 argv_array_pushf(env, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
1103                                  version);
1104         }
1105
1106         if (flags & CONNECT_IPV4) {
1107                 switch (variant) {
1108                 case VARIANT_AUTO:
1109                         BUG("VARIANT_AUTO passed to push_ssh_options");
1110                 case VARIANT_SIMPLE:
1111                         die("ssh variant 'simple' does not support -4");
1112                 case VARIANT_SSH:
1113                 case VARIANT_PLINK:
1114                 case VARIANT_PUTTY:
1115                 case VARIANT_TORTOISEPLINK:
1116                         argv_array_push(args, "-4");
1117                 }
1118         } else if (flags & CONNECT_IPV6) {
1119                 switch (variant) {
1120                 case VARIANT_AUTO:
1121                         BUG("VARIANT_AUTO passed to push_ssh_options");
1122                 case VARIANT_SIMPLE:
1123                         die("ssh variant 'simple' does not support -6");
1124                 case VARIANT_SSH:
1125                 case VARIANT_PLINK:
1126                 case VARIANT_PUTTY:
1127                 case VARIANT_TORTOISEPLINK:
1128                         argv_array_push(args, "-6");
1129                 }
1130         }
1131
1132         if (variant == VARIANT_TORTOISEPLINK)
1133                 argv_array_push(args, "-batch");
1134
1135         if (port) {
1136                 switch (variant) {
1137                 case VARIANT_AUTO:
1138                         BUG("VARIANT_AUTO passed to push_ssh_options");
1139                 case VARIANT_SIMPLE:
1140                         die("ssh variant 'simple' does not support setting port");
1141                 case VARIANT_SSH:
1142                         argv_array_push(args, "-p");
1143                         break;
1144                 case VARIANT_PLINK:
1145                 case VARIANT_PUTTY:
1146                 case VARIANT_TORTOISEPLINK:
1147                         argv_array_push(args, "-P");
1148                 }
1149
1150                 argv_array_push(args, port);
1151         }
1152 }
1153
1154 /* Prepare a child_process for use by Git's SSH-tunneled transport. */
1155 static void fill_ssh_args(struct child_process *conn, const char *ssh_host,
1156                           const char *port, enum protocol_version version,
1157                           int flags)
1158 {
1159         const char *ssh;
1160         enum ssh_variant variant;
1161
1162         if (looks_like_command_line_option(ssh_host))
1163                 die("strange hostname '%s' blocked", ssh_host);
1164
1165         ssh = get_ssh_command();
1166         if (ssh) {
1167                 variant = determine_ssh_variant(ssh, 1);
1168         } else {
1169                 /*
1170                  * GIT_SSH is the no-shell version of
1171                  * GIT_SSH_COMMAND (and must remain so for
1172                  * historical compatibility).
1173                  */
1174                 conn->use_shell = 0;
1175
1176                 ssh = getenv("GIT_SSH");
1177                 if (!ssh)
1178                         ssh = "ssh";
1179                 variant = determine_ssh_variant(ssh, 0);
1180         }
1181
1182         if (variant == VARIANT_AUTO) {
1183                 struct child_process detect = CHILD_PROCESS_INIT;
1184
1185                 detect.use_shell = conn->use_shell;
1186                 detect.no_stdin = detect.no_stdout = detect.no_stderr = 1;
1187
1188                 argv_array_push(&detect.args, ssh);
1189                 argv_array_push(&detect.args, "-G");
1190                 push_ssh_options(&detect.args, &detect.env_array,
1191                                  VARIANT_SSH, port, version, flags);
1192                 argv_array_push(&detect.args, ssh_host);
1193
1194                 variant = run_command(&detect) ? VARIANT_SIMPLE : VARIANT_SSH;
1195         }
1196
1197         argv_array_push(&conn->args, ssh);
1198         push_ssh_options(&conn->args, &conn->env_array, variant, port, version, flags);
1199         argv_array_push(&conn->args, ssh_host);
1200 }
1201
1202 /*
1203  * This returns the dummy child_process `no_fork` if the transport protocol
1204  * does not need fork(2), or a struct child_process object if it does.  Once
1205  * done, finish the connection with finish_connect() with the value returned
1206  * from this function (it is safe to call finish_connect() with NULL to
1207  * support the former case).
1208  *
1209  * If it returns, the connect is successful; it just dies on errors (this
1210  * will hopefully be changed in a libification effort, to return NULL when
1211  * the connection failed).
1212  */
1213 struct child_process *git_connect(int fd[2], const char *url,
1214                                   const char *prog, int flags)
1215 {
1216         char *hostandport, *path;
1217         struct child_process *conn;
1218         enum protocol protocol;
1219         enum protocol_version version = get_protocol_version_config();
1220
1221         /*
1222          * NEEDSWORK: If we are trying to use protocol v2 and we are planning
1223          * to perform a push, then fallback to v0 since the client doesn't know
1224          * how to push yet using v2.
1225          */
1226         if (version == protocol_v2 && !strcmp("git-receive-pack", prog))
1227                 version = protocol_v0;
1228
1229         /* Without this we cannot rely on waitpid() to tell
1230          * what happened to our children.
1231          */
1232         signal(SIGCHLD, SIG_DFL);
1233
1234         protocol = parse_connect_url(url, &hostandport, &path);
1235         if ((flags & CONNECT_DIAG_URL) && (protocol != PROTO_SSH)) {
1236                 printf("Diag: url=%s\n", url ? url : "NULL");
1237                 printf("Diag: protocol=%s\n", prot_name(protocol));
1238                 printf("Diag: hostandport=%s\n", hostandport ? hostandport : "NULL");
1239                 printf("Diag: path=%s\n", path ? path : "NULL");
1240                 conn = NULL;
1241         } else if (protocol == PROTO_GIT) {
1242                 conn = git_connect_git(fd, hostandport, path, prog, version, flags);
1243         } else {
1244                 struct strbuf cmd = STRBUF_INIT;
1245                 const char *const *var;
1246
1247                 conn = xmalloc(sizeof(*conn));
1248                 child_process_init(conn);
1249
1250                 if (looks_like_command_line_option(path))
1251                         die("strange pathname '%s' blocked", path);
1252
1253                 strbuf_addstr(&cmd, prog);
1254                 strbuf_addch(&cmd, ' ');
1255                 sq_quote_buf(&cmd, path);
1256
1257                 /* remove repo-local variables from the environment */
1258                 for (var = local_repo_env; *var; var++)
1259                         argv_array_push(&conn->env_array, *var);
1260
1261                 conn->use_shell = 1;
1262                 conn->in = conn->out = -1;
1263                 if (protocol == PROTO_SSH) {
1264                         char *ssh_host = hostandport;
1265                         const char *port = NULL;
1266                         transport_check_allowed("ssh");
1267                         get_host_and_port(&ssh_host, &port);
1268
1269                         if (!port)
1270                                 port = get_port(ssh_host);
1271
1272                         if (flags & CONNECT_DIAG_URL) {
1273                                 printf("Diag: url=%s\n", url ? url : "NULL");
1274                                 printf("Diag: protocol=%s\n", prot_name(protocol));
1275                                 printf("Diag: userandhost=%s\n", ssh_host ? ssh_host : "NULL");
1276                                 printf("Diag: port=%s\n", port ? port : "NONE");
1277                                 printf("Diag: path=%s\n", path ? path : "NULL");
1278
1279                                 free(hostandport);
1280                                 free(path);
1281                                 free(conn);
1282                                 strbuf_release(&cmd);
1283                                 return NULL;
1284                         }
1285                         fill_ssh_args(conn, ssh_host, port, version, flags);
1286                 } else {
1287                         transport_check_allowed("file");
1288                         if (version > 0) {
1289                                 argv_array_pushf(&conn->env_array, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
1290                                                  version);
1291                         }
1292                 }
1293                 argv_array_push(&conn->args, cmd.buf);
1294
1295                 if (start_command(conn))
1296                         die("unable to fork");
1297
1298                 fd[0] = conn->out; /* read from child's stdout */
1299                 fd[1] = conn->in;  /* write to child's stdin */
1300                 strbuf_release(&cmd);
1301         }
1302         free(hostandport);
1303         free(path);
1304         return conn;
1305 }
1306
1307 int finish_connect(struct child_process *conn)
1308 {
1309         int code;
1310         if (!conn || git_connection_is_socket(conn))
1311                 return 0;
1312
1313         code = finish_command(conn);
1314         free(conn);
1315         return code;
1316 }