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 NORETURN 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                              const struct string_list *server_options)
 413 {
 414         int i;
 415         *list = NULL;
 416
 417         if (server_supports_v2("ls-refs", 1))
 418                 packet_write_fmt(fd_out, "command=ls-refs\n");
 419
 420         if (server_supports_v2("agent", 0))
 421                 packet_write_fmt(fd_out, "agent=%s", git_user_agent_sanitized());
 422
 423         if (server_options && server_options->nr &&
 424             server_supports_v2("server-option", 1))
 425                 for (i = 0; i < server_options->nr; i++)
 426                         packet_write_fmt(fd_out, "server-option=%s",
 427                                          server_options->items[i].string);
 428
 429         packet_delim(fd_out);
 430         /* When pushing we don't want to request the peeled tags */
 431         if (!for_push)
 432                 packet_write_fmt(fd_out, "peel\n");
 433         packet_write_fmt(fd_out, "symrefs\n");
 434         for (i = 0; ref_prefixes && i < ref_prefixes->argc; i++) {
 435                 packet_write_fmt(fd_out, "ref-prefix %s\n",
 436                                  ref_prefixes->argv[i]);
 437         }
 438         packet_flush(fd_out);
 439
 440         /* Process response from server */
 441         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
 442                 if (!process_ref_v2(reader->line, &list))
 443                         die("invalid ls-refs response: %s", reader->line);
 444         }
 445
 446         if (reader->status != PACKET_READ_FLUSH)
 447                 die("expected flush after ref listing");
 448
 449         return list;
 450 }
 451
 452 static const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
 453 {
 454         int len;
 455
 456         if (!feature_list)
 457                 return NULL;
 458
 459         len = strlen(feature);
 460         while (*feature_list) {
 461                 const char *found = strstr(feature_list, feature);
 462                 if (!found)
 463                         return NULL;
 464                 if (feature_list == found || isspace(found[-1])) {
 465                         const char *value = found + len;
 466                         /* feature with no value (e.g., "thin-pack") */
 467                         if (!*value || isspace(*value)) {
 468                                 if (lenp)
 469                                         *lenp = 0;
 470                                 return value;
 471                         }
 472                         /* feature with a value (e.g., "agent=git/1.2.3") */
 473                         else if (*value == '=') {
 474                                 value++;
 475                                 if (lenp)
 476                                         *lenp = strcspn(value, " \t\n");
 477                                 return value;
 478                         }
 479                         /*
 480                          * otherwise we matched a substring of another feature;
 481                          * keep looking
 482                          */
 483                 }
 484                 feature_list = found + 1;
 485         }
 486         return NULL;
 487 }
 488
 489 int parse_feature_request(const char *feature_list, const char *feature)
 490 {
 491         return !!parse_feature_value(feature_list, feature, NULL);
 492 }
 493
 494 const char *server_feature_value(const char *feature, int *len)
 495 {
 496         return parse_feature_value(server_capabilities_v1, feature, len);
 497 }
 498
 499 int server_supports(const char *feature)
 500 {
 501         return !!server_feature_value(feature, NULL);
 502 }
 503
 504 enum protocol {
 505         PROTO_LOCAL = 1,
 506         PROTO_FILE,
 507         PROTO_SSH,
 508         PROTO_GIT
 509 };
 510
 511 int url_is_local_not_ssh(const char *url)
 512 {
 513         const char *colon = strchr(url, ':');
 514         const char *slash = strchr(url, '/');
 515         return !colon || (slash && slash < colon) ||
 516                 has_dos_drive_prefix(url);
 517 }
 518
 519 static const char *prot_name(enum protocol protocol)
 520 {
 521         switch (protocol) {
 522                 case PROTO_LOCAL:
 523                 case PROTO_FILE:
 524                         return "file";
 525                 case PROTO_SSH:
 526                         return "ssh";
 527                 case PROTO_GIT:
 528                         return "git";
 529                 default:
 530                         return "unknown protocol";
 531         }
 532 }
 533
 534 static enum protocol get_protocol(const char *name)
 535 {
 536         if (!strcmp(name, "ssh"))
 537                 return PROTO_SSH;
 538         if (!strcmp(name, "git"))
 539                 return PROTO_GIT;
 540         if (!strcmp(name, "git+ssh")) /* deprecated - do not use */
 541                 return PROTO_SSH;
 542         if (!strcmp(name, "ssh+git")) /* deprecated - do not use */
 543                 return PROTO_SSH;
 544         if (!strcmp(name, "file"))
 545                 return PROTO_FILE;
 546         die("I don't handle protocol '%s'", name);
 547 }
 548
 549 static char *host_end(char **hoststart, int removebrackets)
 550 {
 551         char *host = *hoststart;
 552         char *end;
 553         char *start = strstr(host, "@[");
 554         if (start)
 555                 start++; /* Jump over '@' */
 556         else
 557                 start = host;
 558         if (start[0] == '[') {
 559                 end = strchr(start + 1, ']');
 560                 if (end) {
 561                         if (removebrackets) {
 562                                 *end = 0;
 563                                 memmove(start, start + 1, end - start);
 564                                 end++;
 565                         }
 566                 } else
 567                         end = host;
 568         } else
 569                 end = host;
 570         return end;
 571 }
 572
 573 #define STR_(s) # s
 574 #define STR(s)  STR_(s)
 575
 576 static void get_host_and_port(char **host, const char **port)
 577 {
 578         char *colon, *end;
 579         end = host_end(host, 1);
 580         colon = strchr(end, ':');
 581         if (colon) {
 582                 long portnr = strtol(colon + 1, &end, 10);
 583                 if (end != colon + 1 && *end == '\0' && 0 <= portnr && portnr < 65536) {
 584                         *colon = 0;
 585                         *port = colon + 1;
 586                 } else if (!colon[1]) {
 587                         *colon = 0;
 588                 }
 589         }
 590 }
 591
 592 static void enable_keepalive(int sockfd)
 593 {
 594         int ka = 1;
 595
 596         if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
 597                 fprintf(stderr, "unable to set SO_KEEPALIVE on socket: %s\n",
 598                         strerror(errno));
 599 }
 600
 601 #ifndef NO_IPV6
 602
 603 static const char *ai_name(const struct addrinfo *ai)
 604 {
 605         static char addr[NI_MAXHOST];
 606         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
 607                         NI_NUMERICHOST) != 0)
 608                 xsnprintf(addr, sizeof(addr), "(unknown)");
 609
 610         return addr;
 611 }
 612
 613 /*
 614  * Returns a connected socket() fd, or else die()s.
 615  */
 616 static int git_tcp_connect_sock(char *host, int flags)
 617 {
 618         struct strbuf error_message = STRBUF_INIT;
 619         int sockfd = -1;
 620         const char *port = STR(DEFAULT_GIT_PORT);
 621         struct addrinfo hints, *ai0, *ai;
 622         int gai;
 623         int cnt = 0;
 624
 625         get_host_and_port(&host, &port);
 626         if (!*port)
 627                 port = "<none>";
 628
 629         memset(&hints, 0, sizeof(hints));
 630         if (flags & CONNECT_IPV4)
 631                 hints.ai_family = AF_INET;
 632         else if (flags & CONNECT_IPV6)
 633                 hints.ai_family = AF_INET6;
 634         hints.ai_socktype = SOCK_STREAM;
 635         hints.ai_protocol = IPPROTO_TCP;
 636
 637         if (flags & CONNECT_VERBOSE)
 638                 fprintf(stderr, "Looking up %s ... ", host);
 639
 640         gai = getaddrinfo(host, port, &hints, &ai);
 641         if (gai)
 642                 die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
 643
 644         if (flags & CONNECT_VERBOSE)
 645                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 646
 647         for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
 648                 sockfd = socket(ai->ai_family,
 649                                 ai->ai_socktype, ai->ai_protocol);
 650                 if ((sockfd < 0) ||
 651                     (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
 652                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 653                                     host, cnt, ai_name(ai), strerror(errno));
 654                         if (0 <= sockfd)
 655                                 close(sockfd);
 656                         sockfd = -1;
 657                         continue;
 658                 }
 659                 if (flags & CONNECT_VERBOSE)
 660                         fprintf(stderr, "%s ", ai_name(ai));
 661                 break;
 662         }
 663
 664         freeaddrinfo(ai0);
 665
 666         if (sockfd < 0)
 667                 die("unable to connect to %s:\n%s", host, error_message.buf);
 668
 669         enable_keepalive(sockfd);
 670
 671         if (flags & CONNECT_VERBOSE)
 672                 fprintf(stderr, "done.\n");
 673
 674         strbuf_release(&error_message);
 675
 676         return sockfd;
 677 }
 678
 679 #else /* NO_IPV6 */
 680
 681 /*
 682  * Returns a connected socket() fd, or else die()s.
 683  */
 684 static int git_tcp_connect_sock(char *host, int flags)
 685 {
 686         struct strbuf error_message = STRBUF_INIT;
 687         int sockfd = -1;
 688         const char *port = STR(DEFAULT_GIT_PORT);
 689         char *ep;
 690         struct hostent *he;
 691         struct sockaddr_in sa;
 692         char **ap;
 693         unsigned int nport;
 694         int cnt;
 695
 696         get_host_and_port(&host, &port);
 697
 698         if (flags & CONNECT_VERBOSE)
 699                 fprintf(stderr, "Looking up %s ... ", host);
 700
 701         he = gethostbyname(host);
 702         if (!he)
 703                 die("Unable to look up %s (%s)", host, hstrerror(h_errno));
 704         nport = strtoul(port, &ep, 10);
 705         if ( ep == port || *ep ) {
 706                 /* Not numeric */
 707                 struct servent *se = getservbyname(port,"tcp");
 708                 if ( !se )
 709                         die("Unknown port %s", port);
 710                 nport = se->s_port;
 711         }
 712
 713         if (flags & CONNECT_VERBOSE)
 714                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 715
 716         for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
 717                 memset(&sa, 0, sizeof sa);
 718                 sa.sin_family = he->h_addrtype;
 719                 sa.sin_port = htons(nport);
 720                 memcpy(&sa.sin_addr, *ap, he->h_length);
 721
 722                 sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 723                 if ((sockfd < 0) ||
 724                     connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 725                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 726                                 host,
 727                                 cnt,
 728                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr),
 729                                 strerror(errno));
 730                         if (0 <= sockfd)
 731                                 close(sockfd);
 732                         sockfd = -1;
 733                         continue;
 734                 }
 735                 if (flags & CONNECT_VERBOSE)
 736                         fprintf(stderr, "%s ",
 737                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr));
 738                 break;
 739         }
 740
 741         if (sockfd < 0)
 742                 die("unable to connect to %s:\n%s", host, error_message.buf);
 743
 744         enable_keepalive(sockfd);
 745
 746         if (flags & CONNECT_VERBOSE)
 747                 fprintf(stderr, "done.\n");
 748
 749         return sockfd;
 750 }
 751
 752 #endif /* NO_IPV6 */
 753
 754
 755 /*
 756  * Dummy child_process returned by git_connect() if the transport protocol
 757  * does not need fork(2).
 758  */
 759 static struct child_process no_fork = CHILD_PROCESS_INIT;
 760
 761 int git_connection_is_socket(struct child_process *conn)
 762 {
 763         return conn == &no_fork;
 764 }
 765
 766 static struct child_process *git_tcp_connect(int fd[2], char *host, int flags)
 767 {
 768         int sockfd = git_tcp_connect_sock(host, flags);
 769
 770         fd[0] = sockfd;
 771         fd[1] = dup(sockfd);
 772
 773         return &no_fork;
 774 }
 775
 776
 777 static char *git_proxy_command;
 778
 779 static int git_proxy_command_options(const char *var, const char *value,
 780                 void *cb)
 781 {
 782         if (!strcmp(var, "core.gitproxy")) {
 783                 const char *for_pos;
 784                 int matchlen = -1;
 785                 int hostlen;
 786                 const char *rhost_name = cb;
 787                 int rhost_len = strlen(rhost_name);
 788
 789                 if (git_proxy_command)
 790                         return 0;
 791                 if (!value)
 792                         return config_error_nonbool(var);
 793                 /* [core]
 794                  * ;# matches www.kernel.org as well
 795                  * gitproxy = netcatter-1 for kernel.org
 796                  * gitproxy = netcatter-2 for sample.xz
 797                  * gitproxy = netcatter-default
 798                  */
 799                 for_pos = strstr(value, " for ");
 800                 if (!for_pos)
 801                         /* matches everybody */
 802                         matchlen = strlen(value);
 803                 else {
 804                         hostlen = strlen(for_pos + 5);
 805                         if (rhost_len < hostlen)
 806                                 matchlen = -1;
 807                         else if (!strncmp(for_pos + 5,
 808                                           rhost_name + rhost_len - hostlen,
 809                                           hostlen) &&
 810                                  ((rhost_len == hostlen) ||
 811                                   rhost_name[rhost_len - hostlen -1] == '.'))
 812                                 matchlen = for_pos - value;
 813                         else
 814                                 matchlen = -1;
 815                 }
 816                 if (0 <= matchlen) {
 817                         /* core.gitproxy = none for kernel.org */
 818                         if (matchlen == 4 &&
 819                             !memcmp(value, "none", 4))
 820                                 matchlen = 0;
 821                         git_proxy_command = xmemdupz(value, matchlen);
 822                 }
 823                 return 0;
 824         }
 825
 826         return git_default_config(var, value, cb);
 827 }
 828
 829 static int git_use_proxy(const char *host)
 830 {
 831         git_proxy_command = getenv("GIT_PROXY_COMMAND");
 832         git_config(git_proxy_command_options, (void*)host);
 833         return (git_proxy_command && *git_proxy_command);
 834 }
 835
 836 static struct child_process *git_proxy_connect(int fd[2], char *host)
 837 {
 838         const char *port = STR(DEFAULT_GIT_PORT);
 839         struct child_process *proxy;
 840
 841         get_host_and_port(&host, &port);
 842
 843         if (looks_like_command_line_option(host))
 844                 die("strange hostname '%s' blocked", host);
 845         if (looks_like_command_line_option(port))
 846                 die("strange port '%s' blocked", port);
 847
 848         proxy = xmalloc(sizeof(*proxy));
 849         child_process_init(proxy);
 850         argv_array_push(&proxy->args, git_proxy_command);
 851         argv_array_push(&proxy->args, host);
 852         argv_array_push(&proxy->args, port);
 853         proxy->in = -1;
 854         proxy->out = -1;
 855         if (start_command(proxy))
 856                 die("cannot start proxy %s", git_proxy_command);
 857         fd[0] = proxy->out; /* read from proxy stdout */
 858         fd[1] = proxy->in;  /* write to proxy stdin */
 859         return proxy;
 860 }
 861
 862 static char *get_port(char *host)
 863 {
 864         char *end;
 865         char *p = strchr(host, ':');
 866
 867         if (p) {
 868                 long port = strtol(p + 1, &end, 10);
 869                 if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
 870                         *p = '\0';
 871                         return p+1;
 872                 }
 873         }
 874
 875         return NULL;
 876 }
 877
 878 /*
 879  * Extract protocol and relevant parts from the specified connection URL.
 880  * The caller must free() the returned strings.
 881  */
 882 static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
 883                                        char **ret_path)
 884 {
 885         char *url;
 886         char *host, *path;
 887         char *end;
 888         int separator = '/';
 889         enum protocol protocol = PROTO_LOCAL;
 890
 891         if (is_url(url_orig))
 892                 url = url_decode(url_orig);
 893         else
 894                 url = xstrdup(url_orig);
 895
 896         host = strstr(url, "://");
 897         if (host) {
 898                 *host = '\0';
 899                 protocol = get_protocol(url);
 900                 host += 3;
 901         } else {
 902                 host = url;
 903                 if (!url_is_local_not_ssh(url)) {
 904                         protocol = PROTO_SSH;
 905                         separator = ':';
 906                 }
 907         }
 908
 909         /*
 910          * Don't do destructive transforms as protocol code does
 911          * '[]' unwrapping in get_host_and_port()
 912          */
 913         end = host_end(&host, 0);
 914
 915         if (protocol == PROTO_LOCAL)
 916                 path = end;
 917         else if (protocol == PROTO_FILE && has_dos_drive_prefix(end))
 918                 path = end; /* "file://$(pwd)" may be "file://C:/projects/repo" */
 919         else
 920                 path = strchr(end, separator);
 921
 922         if (!path || !*path)
 923                 die("No path specified. See 'man git-pull' for valid url syntax");
 924
 925         /*
 926          * null-terminate hostname and point path to ~ for URL's like this:
 927          *    ssh://host.xz/~user/repo
 928          */
 929
 930         end = path; /* Need to \0 terminate host here */
 931         if (separator == ':')
 932                 path++; /* path starts after ':' */
 933         if (protocol == PROTO_GIT || protocol == PROTO_SSH) {
 934                 if (path[1] == '~')
 935                         path++;
 936         }
 937
 938         path = xstrdup(path);
 939         *end = '\0';
 940
 941         *ret_host = xstrdup(host);
 942         *ret_path = path;
 943         free(url);
 944         return protocol;
 945 }
 946
 947 static const char *get_ssh_command(void)
 948 {
 949         const char *ssh;
 950
 951         if ((ssh = getenv("GIT_SSH_COMMAND")))
 952                 return ssh;
 953
 954         if (!git_config_get_string_const("core.sshcommand", &ssh))
 955                 return ssh;
 956
 957         return NULL;
 958 }
 959
 960 enum ssh_variant {
 961         VARIANT_AUTO,
 962         VARIANT_SIMPLE,
 963         VARIANT_SSH,
 964         VARIANT_PLINK,
 965         VARIANT_PUTTY,
 966         VARIANT_TORTOISEPLINK,
 967 };
 968
 969 static void override_ssh_variant(enum ssh_variant *ssh_variant)
 970 {
 971         const char *variant = getenv("GIT_SSH_VARIANT");
 972
 973         if (!variant && git_config_get_string_const("ssh.variant", &variant))
 974                 return;
 975
 976         if (!strcmp(variant, "auto"))
 977                 *ssh_variant = VARIANT_AUTO;
 978         else if (!strcmp(variant, "plink"))
 979                 *ssh_variant = VARIANT_PLINK;
 980         else if (!strcmp(variant, "putty"))
 981                 *ssh_variant = VARIANT_PUTTY;
 982         else if (!strcmp(variant, "tortoiseplink"))
 983                 *ssh_variant = VARIANT_TORTOISEPLINK;
 984         else if (!strcmp(variant, "simple"))
 985                 *ssh_variant = VARIANT_SIMPLE;
 986         else
 987                 *ssh_variant = VARIANT_SSH;
 988 }
 989
 990 static enum ssh_variant determine_ssh_variant(const char *ssh_command,
 991                                               int is_cmdline)
 992 {
 993         enum ssh_variant ssh_variant = VARIANT_AUTO;
 994         const char *variant;
 995         char *p = NULL;
 996
 997         override_ssh_variant(&ssh_variant);
 998
 999         if (ssh_variant != VARIANT_AUTO)
1000                 return ssh_variant;
1001
1002         if (!is_cmdline) {
1003                 p = xstrdup(ssh_command);
1004                 variant = basename(p);
1005         } else {
1006                 const char **ssh_argv;
1007
1008                 p = xstrdup(ssh_command);
1009                 if (split_cmdline(p, &ssh_argv) > 0) {
1010                         variant = basename((char *)ssh_argv[0]);
1011                         /*
1012                          * At this point, variant points into the buffer
1013                          * referenced by p, hence we do not need ssh_argv
1014                          * any longer.
1015                          */
1016                         free(ssh_argv);
1017                 } else {
1018                         free(p);
1019                         return ssh_variant;
1020                 }
1021         }
1022
1023         if (!strcasecmp(variant, "ssh") ||
1024             !strcasecmp(variant, "ssh.exe"))
1025                 ssh_variant = VARIANT_SSH;
1026         else if (!strcasecmp(variant, "plink") ||
1027                  !strcasecmp(variant, "plink.exe"))
1028                 ssh_variant = VARIANT_PLINK;
1029         else if (!strcasecmp(variant, "tortoiseplink") ||
1030                  !strcasecmp(variant, "tortoiseplink.exe"))
1031                 ssh_variant = VARIANT_TORTOISEPLINK;
1032
1033         free(p);
1034         return ssh_variant;
1035 }
1036
1037 /*
1038  * Open a connection using Git's native protocol.
1039  *
1040  * The caller is responsible for freeing hostandport, but this function may
1041  * modify it (for example, to truncate it to remove the port part).
1042  */
1043 static struct child_process *git_connect_git(int fd[2], char *hostandport,
1044                                              const char *path, const char *prog,
1045                                              enum protocol_version version,
1046                                              int flags)
1047 {
1048         struct child_process *conn;
1049         struct strbuf request = STRBUF_INIT;
1050         /*
1051          * Set up virtual host information based on where we will
1052          * connect, unless the user has overridden us in
1053          * the environment.
1054          */
1055         char *target_host = getenv("GIT_OVERRIDE_VIRTUAL_HOST");
1056         if (target_host)
1057                 target_host = xstrdup(target_host);
1058         else
1059                 target_host = xstrdup(hostandport);
1060
1061         transport_check_allowed("git");
1062
1063         /*
1064          * These underlying connection commands die() if they
1065          * cannot connect.
1066          */
1067         if (git_use_proxy(hostandport))
1068                 conn = git_proxy_connect(fd, hostandport);
1069         else
1070                 conn = git_tcp_connect(fd, hostandport, flags);
1071         /*
1072          * Separate original protocol components prog and path
1073          * from extended host header with a NUL byte.
1074          *
1075          * Note: Do not add any other headers here!  Doing so
1076          * will cause older git-daemon servers to crash.
1077          */
1078         strbuf_addf(&request,
1079                     "%s %s%chost=%s%c",
1080                     prog, path, 0,
1081                     target_host, 0);
1082
1083         /* If using a new version put that stuff here after a second null byte */
1084         if (version > 0) {
1085                 strbuf_addch(&request, '\0');
1086                 strbuf_addf(&request, "version=%d%c",
1087                             version, '\0');
1088         }
1089
1090         packet_write(fd[1], request.buf, request.len);
1091
1092         free(target_host);
1093         strbuf_release(&request);
1094         return conn;
1095 }
1096
1097 /*
1098  * Append the appropriate environment variables to `env` and options to
1099  * `args` for running ssh in Git's SSH-tunneled transport.
1100  */
1101 static void push_ssh_options(struct argv_array *args, struct argv_array *env,
1102                              enum ssh_variant variant, const char *port,
1103                              enum protocol_version version, int flags)
1104 {
1105         if (variant == VARIANT_SSH &&
1106             version > 0) {
1107                 argv_array_push(args, "-o");
1108                 argv_array_push(args, "SendEnv=" GIT_PROTOCOL_ENVIRONMENT);
1109                 argv_array_pushf(env, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
1110                                  version);
1111         }
1112
1113         if (flags & CONNECT_IPV4) {
1114                 switch (variant) {
1115                 case VARIANT_AUTO:
1116                         BUG("VARIANT_AUTO passed to push_ssh_options");
1117                 case VARIANT_SIMPLE:
1118                         die("ssh variant 'simple' does not support -4");
1119                 case VARIANT_SSH:
1120                 case VARIANT_PLINK:
1121                 case VARIANT_PUTTY:
1122                 case VARIANT_TORTOISEPLINK:
1123                         argv_array_push(args, "-4");
1124                 }
1125         } else if (flags & CONNECT_IPV6) {
1126                 switch (variant) {
1127                 case VARIANT_AUTO:
1128                         BUG("VARIANT_AUTO passed to push_ssh_options");
1129                 case VARIANT_SIMPLE:
1130                         die("ssh variant 'simple' does not support -6");
1131                 case VARIANT_SSH:
1132                 case VARIANT_PLINK:
1133                 case VARIANT_PUTTY:
1134                 case VARIANT_TORTOISEPLINK:
1135                         argv_array_push(args, "-6");
1136                 }
1137         }
1138
1139         if (variant == VARIANT_TORTOISEPLINK)
1140                 argv_array_push(args, "-batch");
1141
1142         if (port) {
1143                 switch (variant) {
1144                 case VARIANT_AUTO:
1145                         BUG("VARIANT_AUTO passed to push_ssh_options");
1146                 case VARIANT_SIMPLE:
1147                         die("ssh variant 'simple' does not support setting port");
1148                 case VARIANT_SSH:
1149                         argv_array_push(args, "-p");
1150                         break;
1151                 case VARIANT_PLINK:
1152                 case VARIANT_PUTTY:
1153                 case VARIANT_TORTOISEPLINK:
1154                         argv_array_push(args, "-P");
1155                 }
1156
1157                 argv_array_push(args, port);
1158         }
1159 }
1160
1161 /* Prepare a child_process for use by Git's SSH-tunneled transport. */
1162 static void fill_ssh_args(struct child_process *conn, const char *ssh_host,
1163                           const char *port, enum protocol_version version,
1164                           int flags)
1165 {
1166         const char *ssh;
1167         enum ssh_variant variant;
1168
1169         if (looks_like_command_line_option(ssh_host))
1170                 die("strange hostname '%s' blocked", ssh_host);
1171
1172         ssh = get_ssh_command();
1173         if (ssh) {
1174                 variant = determine_ssh_variant(ssh, 1);
1175         } else {
1176                 /*
1177                  * GIT_SSH is the no-shell version of
1178                  * GIT_SSH_COMMAND (and must remain so for
1179                  * historical compatibility).
1180                  */
1181                 conn->use_shell = 0;
1182
1183                 ssh = getenv("GIT_SSH");
1184                 if (!ssh)
1185                         ssh = "ssh";
1186                 variant = determine_ssh_variant(ssh, 0);
1187         }
1188
1189         if (variant == VARIANT_AUTO) {
1190                 struct child_process detect = CHILD_PROCESS_INIT;
1191
1192                 detect.use_shell = conn->use_shell;
1193                 detect.no_stdin = detect.no_stdout = detect.no_stderr = 1;
1194
1195                 argv_array_push(&detect.args, ssh);
1196                 argv_array_push(&detect.args, "-G");
1197                 push_ssh_options(&detect.args, &detect.env_array,
1198                                  VARIANT_SSH, port, version, flags);
1199                 argv_array_push(&detect.args, ssh_host);
1200
1201                 variant = run_command(&detect) ? VARIANT_SIMPLE : VARIANT_SSH;
1202         }
1203
1204         argv_array_push(&conn->args, ssh);
1205         push_ssh_options(&conn->args, &conn->env_array, variant, port, version, flags);
1206         argv_array_push(&conn->args, ssh_host);
1207 }
1208
1209 /*
1210  * This returns the dummy child_process `no_fork` if the transport protocol
1211  * does not need fork(2), or a struct child_process object if it does.  Once
1212  * done, finish the connection with finish_connect() with the value returned
1213  * from this function (it is safe to call finish_connect() with NULL to
1214  * support the former case).
1215  *
1216  * If it returns, the connect is successful; it just dies on errors (this
1217  * will hopefully be changed in a libification effort, to return NULL when
1218  * the connection failed).
1219  */
1220 struct child_process *git_connect(int fd[2], const char *url,
1221                                   const char *prog, int flags)
1222 {
1223         char *hostandport, *path;
1224         struct child_process *conn;
1225         enum protocol protocol;
1226         enum protocol_version version = get_protocol_version_config();
1227
1228         /*
1229          * NEEDSWORK: If we are trying to use protocol v2 and we are planning
1230          * to perform a push, then fallback to v0 since the client doesn't know
1231          * how to push yet using v2.
1232          */
1233         if (version == protocol_v2 && !strcmp("git-receive-pack", prog))
1234                 version = protocol_v0;
1235
1236         /* Without this we cannot rely on waitpid() to tell
1237          * what happened to our children.
1238          */
1239         signal(SIGCHLD, SIG_DFL);
1240
1241         protocol = parse_connect_url(url, &hostandport, &path);
1242         if ((flags & CONNECT_DIAG_URL) && (protocol != PROTO_SSH)) {
1243                 printf("Diag: url=%s\n", url ? url : "NULL");
1244                 printf("Diag: protocol=%s\n", prot_name(protocol));
1245                 printf("Diag: hostandport=%s\n", hostandport ? hostandport : "NULL");
1246                 printf("Diag: path=%s\n", path ? path : "NULL");
1247                 conn = NULL;
1248         } else if (protocol == PROTO_GIT) {
1249                 conn = git_connect_git(fd, hostandport, path, prog, version, flags);
1250         } else {
1251                 struct strbuf cmd = STRBUF_INIT;
1252                 const char *const *var;
1253
1254                 conn = xmalloc(sizeof(*conn));
1255                 child_process_init(conn);
1256
1257                 if (looks_like_command_line_option(path))
1258                         die("strange pathname '%s' blocked", path);
1259
1260                 strbuf_addstr(&cmd, prog);
1261                 strbuf_addch(&cmd, ' ');
1262                 sq_quote_buf(&cmd, path);
1263
1264                 /* remove repo-local variables from the environment */
1265                 for (var = local_repo_env; *var; var++)
1266                         argv_array_push(&conn->env_array, *var);
1267
1268                 conn->use_shell = 1;
1269                 conn->in = conn->out = -1;
1270                 if (protocol == PROTO_SSH) {
1271                         char *ssh_host = hostandport;
1272                         const char *port = NULL;
1273                         transport_check_allowed("ssh");
1274                         get_host_and_port(&ssh_host, &port);
1275
1276                         if (!port)
1277                                 port = get_port(ssh_host);
1278
1279                         if (flags & CONNECT_DIAG_URL) {
1280                                 printf("Diag: url=%s\n", url ? url : "NULL");
1281                                 printf("Diag: protocol=%s\n", prot_name(protocol));
1282                                 printf("Diag: userandhost=%s\n", ssh_host ? ssh_host : "NULL");
1283                                 printf("Diag: port=%s\n", port ? port : "NONE");
1284                                 printf("Diag: path=%s\n", path ? path : "NULL");
1285
1286                                 free(hostandport);
1287                                 free(path);
1288                                 free(conn);
1289                                 strbuf_release(&cmd);
1290                                 return NULL;
1291                         }
1292                         fill_ssh_args(conn, ssh_host, port, version, flags);
1293                 } else {
1294                         transport_check_allowed("file");
1295                         if (version > 0) {
1296                                 argv_array_pushf(&conn->env_array, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
1297                                                  version);
1298                         }
1299                 }
1300                 argv_array_push(&conn->args, cmd.buf);
1301
1302                 if (start_command(conn))
1303                         die("unable to fork");
1304
1305                 fd[0] = conn->out; /* read from child's stdout */
1306                 fd[1] = conn->in;  /* write to child's stdin */
1307                 strbuf_release(&cmd);
1308         }
1309         free(hostandport);
1310         free(path);
1311         return conn;
1312 }
1313
1314 int finish_connect(struct child_process *conn)
1315 {
1316         int code;
1317         if (!conn || git_connection_is_socket(conn))
1318                 return 0;
1319
1320         code = finish_command(conn);
1321         free(conn);
1322         return code;
1323 }