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

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