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