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