0b111e62d760bcf0d3948240de489a2249f7cffa
   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
  17static char *server_capabilities;
  18static const char *parse_feature_value(const char *, const char *, int *);
  19
  20static 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
  44int check_ref_type(const struct ref *ref, int flags)
  45{
  46        return check_ref(ref->name, flags);
  47}
  48
  49static 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
  65enum 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
  99static 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;
 120reject:
 121        free(sym);
 122        return;
 123}
 124
 125static 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
 152static 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
 161static 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
 175static 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
 182static 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
 208static 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
 226enum 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 */
 236struct ref **get_remote_heads(struct packet_reader *reader,
 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        const char *arg;
 245
 246        *list = NULL;
 247
 248        while (state != EXPECTING_DONE) {
 249                switch (packet_reader_read(reader)) {
 250                case PACKET_READ_EOF:
 251                        die_initial_contact(1);
 252                case PACKET_READ_NORMAL:
 253                        len = reader->pktlen;
 254                        if (len > 4 && skip_prefix(reader->line, "ERR ", &arg))
 255                                die("remote error: %s", arg);
 256                        break;
 257                case PACKET_READ_FLUSH:
 258                        state = EXPECTING_DONE;
 259                        break;
 260                case PACKET_READ_DELIM:
 261                        die("invalid packet");
 262                }
 263
 264                switch (state) {
 265                case EXPECTING_FIRST_REF:
 266                        process_capabilities(reader->line, &len);
 267                        if (process_dummy_ref(reader->line)) {
 268                                state = EXPECTING_SHALLOW;
 269                                break;
 270                        }
 271                        state = EXPECTING_REF;
 272                        /* fallthrough */
 273                case EXPECTING_REF:
 274                        if (process_ref(reader->line, len, &list, flags, extra_have))
 275                                break;
 276                        state = EXPECTING_SHALLOW;
 277                        /* fallthrough */
 278                case EXPECTING_SHALLOW:
 279                        if (process_shallow(reader->line, len, shallow_points))
 280                                break;
 281                        die("protocol error: unexpected '%s'", reader->line);
 282                case EXPECTING_DONE:
 283                        break;
 284                }
 285        }
 286
 287        annotate_refs_with_symref_info(*orig_list);
 288
 289        return list;
 290}
 291
 292static const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
 293{
 294        int len;
 295
 296        if (!feature_list)
 297                return NULL;
 298
 299        len = strlen(feature);
 300        while (*feature_list) {
 301                const char *found = strstr(feature_list, feature);
 302                if (!found)
 303                        return NULL;
 304                if (feature_list == found || isspace(found[-1])) {
 305                        const char *value = found + len;
 306                        /* feature with no value (e.g., "thin-pack") */
 307                        if (!*value || isspace(*value)) {
 308                                if (lenp)
 309                                        *lenp = 0;
 310                                return value;
 311                        }
 312                        /* feature with a value (e.g., "agent=git/1.2.3") */
 313                        else if (*value == '=') {
 314                                value++;
 315                                if (lenp)
 316                                        *lenp = strcspn(value, " \t\n");
 317                                return value;
 318                        }
 319                        /*
 320                         * otherwise we matched a substring of another feature;
 321                         * keep looking
 322                         */
 323                }
 324                feature_list = found + 1;
 325        }
 326        return NULL;
 327}
 328
 329int parse_feature_request(const char *feature_list, const char *feature)
 330{
 331        return !!parse_feature_value(feature_list, feature, NULL);
 332}
 333
 334const char *server_feature_value(const char *feature, int *len)
 335{
 336        return parse_feature_value(server_capabilities, feature, len);
 337}
 338
 339int server_supports(const char *feature)
 340{
 341        return !!server_feature_value(feature, NULL);
 342}
 343
 344enum protocol {
 345        PROTO_LOCAL = 1,
 346        PROTO_FILE,
 347        PROTO_SSH,
 348        PROTO_GIT
 349};
 350
 351int url_is_local_not_ssh(const char *url)
 352{
 353        const char *colon = strchr(url, ':');
 354        const char *slash = strchr(url, '/');
 355        return !colon || (slash && slash < colon) ||
 356                has_dos_drive_prefix(url);
 357}
 358
 359static const char *prot_name(enum protocol protocol)
 360{
 361        switch (protocol) {
 362                case PROTO_LOCAL:
 363                case PROTO_FILE:
 364                        return "file";
 365                case PROTO_SSH:
 366                        return "ssh";
 367                case PROTO_GIT:
 368                        return "git";
 369                default:
 370                        return "unknown protocol";
 371        }
 372}
 373
 374static enum protocol get_protocol(const char *name)
 375{
 376        if (!strcmp(name, "ssh"))
 377                return PROTO_SSH;
 378        if (!strcmp(name, "git"))
 379                return PROTO_GIT;
 380        if (!strcmp(name, "git+ssh")) /* deprecated - do not use */
 381                return PROTO_SSH;
 382        if (!strcmp(name, "ssh+git")) /* deprecated - do not use */
 383                return PROTO_SSH;
 384        if (!strcmp(name, "file"))
 385                return PROTO_FILE;
 386        die("I don't handle protocol '%s'", name);
 387}
 388
 389static char *host_end(char **hoststart, int removebrackets)
 390{
 391        char *host = *hoststart;
 392        char *end;
 393        char *start = strstr(host, "@[");
 394        if (start)
 395                start++; /* Jump over '@' */
 396        else
 397                start = host;
 398        if (start[0] == '[') {
 399                end = strchr(start + 1, ']');
 400                if (end) {
 401                        if (removebrackets) {
 402                                *end = 0;
 403                                memmove(start, start + 1, end - start);
 404                                end++;
 405                        }
 406                } else
 407                        end = host;
 408        } else
 409                end = host;
 410        return end;
 411}
 412
 413#define STR_(s) # s
 414#define STR(s)  STR_(s)
 415
 416static void get_host_and_port(char **host, const char **port)
 417{
 418        char *colon, *end;
 419        end = host_end(host, 1);
 420        colon = strchr(end, ':');
 421        if (colon) {
 422                long portnr = strtol(colon + 1, &end, 10);
 423                if (end != colon + 1 && *end == '\0' && 0 <= portnr && portnr < 65536) {
 424                        *colon = 0;
 425                        *port = colon + 1;
 426                } else if (!colon[1]) {
 427                        *colon = 0;
 428                }
 429        }
 430}
 431
 432static void enable_keepalive(int sockfd)
 433{
 434        int ka = 1;
 435
 436        if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
 437                fprintf(stderr, "unable to set SO_KEEPALIVE on socket: %s\n",
 438                        strerror(errno));
 439}
 440
 441#ifndef NO_IPV6
 442
 443static const char *ai_name(const struct addrinfo *ai)
 444{
 445        static char addr[NI_MAXHOST];
 446        if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
 447                        NI_NUMERICHOST) != 0)
 448                xsnprintf(addr, sizeof(addr), "(unknown)");
 449
 450        return addr;
 451}
 452
 453/*
 454 * Returns a connected socket() fd, or else die()s.
 455 */
 456static int git_tcp_connect_sock(char *host, int flags)
 457{
 458        struct strbuf error_message = STRBUF_INIT;
 459        int sockfd = -1;
 460        const char *port = STR(DEFAULT_GIT_PORT);
 461        struct addrinfo hints, *ai0, *ai;
 462        int gai;
 463        int cnt = 0;
 464
 465        get_host_and_port(&host, &port);
 466        if (!*port)
 467                port = "<none>";
 468
 469        memset(&hints, 0, sizeof(hints));
 470        if (flags & CONNECT_IPV4)
 471                hints.ai_family = AF_INET;
 472        else if (flags & CONNECT_IPV6)
 473                hints.ai_family = AF_INET6;
 474        hints.ai_socktype = SOCK_STREAM;
 475        hints.ai_protocol = IPPROTO_TCP;
 476
 477        if (flags & CONNECT_VERBOSE)
 478                fprintf(stderr, "Looking up %s ... ", host);
 479
 480        gai = getaddrinfo(host, port, &hints, &ai);
 481        if (gai)
 482                die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
 483
 484        if (flags & CONNECT_VERBOSE)
 485                fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 486
 487        for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
 488                sockfd = socket(ai->ai_family,
 489                                ai->ai_socktype, ai->ai_protocol);
 490                if ((sockfd < 0) ||
 491                    (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
 492                        strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 493                                    host, cnt, ai_name(ai), strerror(errno));
 494                        if (0 <= sockfd)
 495                                close(sockfd);
 496                        sockfd = -1;
 497                        continue;
 498                }
 499                if (flags & CONNECT_VERBOSE)
 500                        fprintf(stderr, "%s ", ai_name(ai));
 501                break;
 502        }
 503
 504        freeaddrinfo(ai0);
 505
 506        if (sockfd < 0)
 507                die("unable to connect to %s:\n%s", host, error_message.buf);
 508
 509        enable_keepalive(sockfd);
 510
 511        if (flags & CONNECT_VERBOSE)
 512                fprintf(stderr, "done.\n");
 513
 514        strbuf_release(&error_message);
 515
 516        return sockfd;
 517}
 518
 519#else /* NO_IPV6 */
 520
 521/*
 522 * Returns a connected socket() fd, or else die()s.
 523 */
 524static int git_tcp_connect_sock(char *host, int flags)
 525{
 526        struct strbuf error_message = STRBUF_INIT;
 527        int sockfd = -1;
 528        const char *port = STR(DEFAULT_GIT_PORT);
 529        char *ep;
 530        struct hostent *he;
 531        struct sockaddr_in sa;
 532        char **ap;
 533        unsigned int nport;
 534        int cnt;
 535
 536        get_host_and_port(&host, &port);
 537
 538        if (flags & CONNECT_VERBOSE)
 539                fprintf(stderr, "Looking up %s ... ", host);
 540
 541        he = gethostbyname(host);
 542        if (!he)
 543                die("Unable to look up %s (%s)", host, hstrerror(h_errno));
 544        nport = strtoul(port, &ep, 10);
 545        if ( ep == port || *ep ) {
 546                /* Not numeric */
 547                struct servent *se = getservbyname(port,"tcp");
 548                if ( !se )
 549                        die("Unknown port %s", port);
 550                nport = se->s_port;
 551        }
 552
 553        if (flags & CONNECT_VERBOSE)
 554                fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 555
 556        for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
 557                memset(&sa, 0, sizeof sa);
 558                sa.sin_family = he->h_addrtype;
 559                sa.sin_port = htons(nport);
 560                memcpy(&sa.sin_addr, *ap, he->h_length);
 561
 562                sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 563                if ((sockfd < 0) ||
 564                    connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 565                        strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 566                                host,
 567                                cnt,
 568                                inet_ntoa(*(struct in_addr *)&sa.sin_addr),
 569                                strerror(errno));
 570                        if (0 <= sockfd)
 571                                close(sockfd);
 572                        sockfd = -1;
 573                        continue;
 574                }
 575                if (flags & CONNECT_VERBOSE)
 576                        fprintf(stderr, "%s ",
 577                                inet_ntoa(*(struct in_addr *)&sa.sin_addr));
 578                break;
 579        }
 580
 581        if (sockfd < 0)
 582                die("unable to connect to %s:\n%s", host, error_message.buf);
 583
 584        enable_keepalive(sockfd);
 585
 586        if (flags & CONNECT_VERBOSE)
 587                fprintf(stderr, "done.\n");
 588
 589        return sockfd;
 590}
 591
 592#endif /* NO_IPV6 */
 593
 594
 595/*
 596 * Dummy child_process returned by git_connect() if the transport protocol
 597 * does not need fork(2).
 598 */
 599static struct child_process no_fork = CHILD_PROCESS_INIT;
 600
 601int git_connection_is_socket(struct child_process *conn)
 602{
 603        return conn == &no_fork;
 604}
 605
 606static struct child_process *git_tcp_connect(int fd[2], char *host, int flags)
 607{
 608        int sockfd = git_tcp_connect_sock(host, flags);
 609
 610        fd[0] = sockfd;
 611        fd[1] = dup(sockfd);
 612
 613        return &no_fork;
 614}
 615
 616
 617static char *git_proxy_command;
 618
 619static int git_proxy_command_options(const char *var, const char *value,
 620                void *cb)
 621{
 622        if (!strcmp(var, "core.gitproxy")) {
 623                const char *for_pos;
 624                int matchlen = -1;
 625                int hostlen;
 626                const char *rhost_name = cb;
 627                int rhost_len = strlen(rhost_name);
 628
 629                if (git_proxy_command)
 630                        return 0;
 631                if (!value)
 632                        return config_error_nonbool(var);
 633                /* [core]
 634                 * ;# matches www.kernel.org as well
 635                 * gitproxy = netcatter-1 for kernel.org
 636                 * gitproxy = netcatter-2 for sample.xz
 637                 * gitproxy = netcatter-default
 638                 */
 639                for_pos = strstr(value, " for ");
 640                if (!for_pos)
 641                        /* matches everybody */
 642                        matchlen = strlen(value);
 643                else {
 644                        hostlen = strlen(for_pos + 5);
 645                        if (rhost_len < hostlen)
 646                                matchlen = -1;
 647                        else if (!strncmp(for_pos + 5,
 648                                          rhost_name + rhost_len - hostlen,
 649                                          hostlen) &&
 650                                 ((rhost_len == hostlen) ||
 651                                  rhost_name[rhost_len - hostlen -1] == '.'))
 652                                matchlen = for_pos - value;
 653                        else
 654                                matchlen = -1;
 655                }
 656                if (0 <= matchlen) {
 657                        /* core.gitproxy = none for kernel.org */
 658                        if (matchlen == 4 &&
 659                            !memcmp(value, "none", 4))
 660                                matchlen = 0;
 661                        git_proxy_command = xmemdupz(value, matchlen);
 662                }
 663                return 0;
 664        }
 665
 666        return git_default_config(var, value, cb);
 667}
 668
 669static int git_use_proxy(const char *host)
 670{
 671        git_proxy_command = getenv("GIT_PROXY_COMMAND");
 672        git_config(git_proxy_command_options, (void*)host);
 673        return (git_proxy_command && *git_proxy_command);
 674}
 675
 676static struct child_process *git_proxy_connect(int fd[2], char *host)
 677{
 678        const char *port = STR(DEFAULT_GIT_PORT);
 679        struct child_process *proxy;
 680
 681        get_host_and_port(&host, &port);
 682
 683        if (looks_like_command_line_option(host))
 684                die("strange hostname '%s' blocked", host);
 685        if (looks_like_command_line_option(port))
 686                die("strange port '%s' blocked", port);
 687
 688        proxy = xmalloc(sizeof(*proxy));
 689        child_process_init(proxy);
 690        argv_array_push(&proxy->args, git_proxy_command);
 691        argv_array_push(&proxy->args, host);
 692        argv_array_push(&proxy->args, port);
 693        proxy->in = -1;
 694        proxy->out = -1;
 695        if (start_command(proxy))
 696                die("cannot start proxy %s", git_proxy_command);
 697        fd[0] = proxy->out; /* read from proxy stdout */
 698        fd[1] = proxy->in;  /* write to proxy stdin */
 699        return proxy;
 700}
 701
 702static char *get_port(char *host)
 703{
 704        char *end;
 705        char *p = strchr(host, ':');
 706
 707        if (p) {
 708                long port = strtol(p + 1, &end, 10);
 709                if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
 710                        *p = '\0';
 711                        return p+1;
 712                }
 713        }
 714
 715        return NULL;
 716}
 717
 718/*
 719 * Extract protocol and relevant parts from the specified connection URL.
 720 * The caller must free() the returned strings.
 721 */
 722static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
 723                                       char **ret_path)
 724{
 725        char *url;
 726        char *host, *path;
 727        char *end;
 728        int separator = '/';
 729        enum protocol protocol = PROTO_LOCAL;
 730
 731        if (is_url(url_orig))
 732                url = url_decode(url_orig);
 733        else
 734                url = xstrdup(url_orig);
 735
 736        host = strstr(url, "://");
 737        if (host) {
 738                *host = '\0';
 739                protocol = get_protocol(url);
 740                host += 3;
 741        } else {
 742                host = url;
 743                if (!url_is_local_not_ssh(url)) {
 744                        protocol = PROTO_SSH;
 745                        separator = ':';
 746                }
 747        }
 748
 749        /*
 750         * Don't do destructive transforms as protocol code does
 751         * '[]' unwrapping in get_host_and_port()
 752         */
 753        end = host_end(&host, 0);
 754
 755        if (protocol == PROTO_LOCAL)
 756                path = end;
 757        else if (protocol == PROTO_FILE && has_dos_drive_prefix(end))
 758                path = end; /* "file://$(pwd)" may be "file://C:/projects/repo" */
 759        else
 760                path = strchr(end, separator);
 761
 762        if (!path || !*path)
 763                die("No path specified. See 'man git-pull' for valid url syntax");
 764
 765        /*
 766         * null-terminate hostname and point path to ~ for URL's like this:
 767         *    ssh://host.xz/~user/repo
 768         */
 769
 770        end = path; /* Need to \0 terminate host here */
 771        if (separator == ':')
 772                path++; /* path starts after ':' */
 773        if (protocol == PROTO_GIT || protocol == PROTO_SSH) {
 774                if (path[1] == '~')
 775                        path++;
 776        }
 777
 778        path = xstrdup(path);
 779        *end = '\0';
 780
 781        *ret_host = xstrdup(host);
 782        *ret_path = path;
 783        free(url);
 784        return protocol;
 785}
 786
 787static const char *get_ssh_command(void)
 788{
 789        const char *ssh;
 790
 791        if ((ssh = getenv("GIT_SSH_COMMAND")))
 792                return ssh;
 793
 794        if (!git_config_get_string_const("core.sshcommand", &ssh))
 795                return ssh;
 796
 797        return NULL;
 798}
 799
 800enum ssh_variant {
 801        VARIANT_AUTO,
 802        VARIANT_SIMPLE,
 803        VARIANT_SSH,
 804        VARIANT_PLINK,
 805        VARIANT_PUTTY,
 806        VARIANT_TORTOISEPLINK,
 807};
 808
 809static void override_ssh_variant(enum ssh_variant *ssh_variant)
 810{
 811        const char *variant = getenv("GIT_SSH_VARIANT");
 812
 813        if (!variant && git_config_get_string_const("ssh.variant", &variant))
 814                return;
 815
 816        if (!strcmp(variant, "auto"))
 817                *ssh_variant = VARIANT_AUTO;
 818        else if (!strcmp(variant, "plink"))
 819                *ssh_variant = VARIANT_PLINK;
 820        else if (!strcmp(variant, "putty"))
 821                *ssh_variant = VARIANT_PUTTY;
 822        else if (!strcmp(variant, "tortoiseplink"))
 823                *ssh_variant = VARIANT_TORTOISEPLINK;
 824        else if (!strcmp(variant, "simple"))
 825                *ssh_variant = VARIANT_SIMPLE;
 826        else
 827                *ssh_variant = VARIANT_SSH;
 828}
 829
 830static enum ssh_variant determine_ssh_variant(const char *ssh_command,
 831                                              int is_cmdline)
 832{
 833        enum ssh_variant ssh_variant = VARIANT_AUTO;
 834        const char *variant;
 835        char *p = NULL;
 836
 837        override_ssh_variant(&ssh_variant);
 838
 839        if (ssh_variant != VARIANT_AUTO)
 840                return ssh_variant;
 841
 842        if (!is_cmdline) {
 843                p = xstrdup(ssh_command);
 844                variant = basename(p);
 845        } else {
 846                const char **ssh_argv;
 847
 848                p = xstrdup(ssh_command);
 849                if (split_cmdline(p, &ssh_argv) > 0) {
 850                        variant = basename((char *)ssh_argv[0]);
 851                        /*
 852                         * At this point, variant points into the buffer
 853                         * referenced by p, hence we do not need ssh_argv
 854                         * any longer.
 855                         */
 856                        free(ssh_argv);
 857                } else {
 858                        free(p);
 859                        return ssh_variant;
 860                }
 861        }
 862
 863        if (!strcasecmp(variant, "ssh") ||
 864            !strcasecmp(variant, "ssh.exe"))
 865                ssh_variant = VARIANT_SSH;
 866        else if (!strcasecmp(variant, "plink") ||
 867                 !strcasecmp(variant, "plink.exe"))
 868                ssh_variant = VARIANT_PLINK;
 869        else if (!strcasecmp(variant, "tortoiseplink") ||
 870                 !strcasecmp(variant, "tortoiseplink.exe"))
 871                ssh_variant = VARIANT_TORTOISEPLINK;
 872
 873        free(p);
 874        return ssh_variant;
 875}
 876
 877/*
 878 * Open a connection using Git's native protocol.
 879 *
 880 * The caller is responsible for freeing hostandport, but this function may
 881 * modify it (for example, to truncate it to remove the port part).
 882 */
 883static struct child_process *git_connect_git(int fd[2], char *hostandport,
 884                                             const char *path, const char *prog,
 885                                             int flags)
 886{
 887        struct child_process *conn;
 888        struct strbuf request = STRBUF_INIT;
 889        /*
 890         * Set up virtual host information based on where we will
 891         * connect, unless the user has overridden us in
 892         * the environment.
 893         */
 894        char *target_host = getenv("GIT_OVERRIDE_VIRTUAL_HOST");
 895        if (target_host)
 896                target_host = xstrdup(target_host);
 897        else
 898                target_host = xstrdup(hostandport);
 899
 900        transport_check_allowed("git");
 901
 902        /*
 903         * These underlying connection commands die() if they
 904         * cannot connect.
 905         */
 906        if (git_use_proxy(hostandport))
 907                conn = git_proxy_connect(fd, hostandport);
 908        else
 909                conn = git_tcp_connect(fd, hostandport, flags);
 910        /*
 911         * Separate original protocol components prog and path
 912         * from extended host header with a NUL byte.
 913         *
 914         * Note: Do not add any other headers here!  Doing so
 915         * will cause older git-daemon servers to crash.
 916         */
 917        strbuf_addf(&request,
 918                    "%s %s%chost=%s%c",
 919                    prog, path, 0,
 920                    target_host, 0);
 921
 922        /* If using a new version put that stuff here after a second null byte */
 923        if (get_protocol_version_config() > 0) {
 924                strbuf_addch(&request, '\0');
 925                strbuf_addf(&request, "version=%d%c",
 926                            get_protocol_version_config(), '\0');
 927        }
 928
 929        packet_write(fd[1], request.buf, request.len);
 930
 931        free(target_host);
 932        strbuf_release(&request);
 933        return conn;
 934}
 935
 936/*
 937 * Append the appropriate environment variables to `env` and options to
 938 * `args` for running ssh in Git's SSH-tunneled transport.
 939 */
 940static void push_ssh_options(struct argv_array *args, struct argv_array *env,
 941                             enum ssh_variant variant, const char *port,
 942                             int flags)
 943{
 944        if (variant == VARIANT_SSH &&
 945            get_protocol_version_config() > 0) {
 946                argv_array_push(args, "-o");
 947                argv_array_push(args, "SendEnv=" GIT_PROTOCOL_ENVIRONMENT);
 948                argv_array_pushf(env, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
 949                                 get_protocol_version_config());
 950        }
 951
 952        if (flags & CONNECT_IPV4) {
 953                switch (variant) {
 954                case VARIANT_AUTO:
 955                        BUG("VARIANT_AUTO passed to push_ssh_options");
 956                case VARIANT_SIMPLE:
 957                        die("ssh variant 'simple' does not support -4");
 958                case VARIANT_SSH:
 959                case VARIANT_PLINK:
 960                case VARIANT_PUTTY:
 961                case VARIANT_TORTOISEPLINK:
 962                        argv_array_push(args, "-4");
 963                }
 964        } else if (flags & CONNECT_IPV6) {
 965                switch (variant) {
 966                case VARIANT_AUTO:
 967                        BUG("VARIANT_AUTO passed to push_ssh_options");
 968                case VARIANT_SIMPLE:
 969                        die("ssh variant 'simple' does not support -6");
 970                case VARIANT_SSH:
 971                case VARIANT_PLINK:
 972                case VARIANT_PUTTY:
 973                case VARIANT_TORTOISEPLINK:
 974                        argv_array_push(args, "-6");
 975                }
 976        }
 977
 978        if (variant == VARIANT_TORTOISEPLINK)
 979                argv_array_push(args, "-batch");
 980
 981        if (port) {
 982                switch (variant) {
 983                case VARIANT_AUTO:
 984                        BUG("VARIANT_AUTO passed to push_ssh_options");
 985                case VARIANT_SIMPLE:
 986                        die("ssh variant 'simple' does not support setting port");
 987                case VARIANT_SSH:
 988                        argv_array_push(args, "-p");
 989                        break;
 990                case VARIANT_PLINK:
 991                case VARIANT_PUTTY:
 992                case VARIANT_TORTOISEPLINK:
 993                        argv_array_push(args, "-P");
 994                }
 995
 996                argv_array_push(args, port);
 997        }
 998}
 999
1000/* Prepare a child_process for use by Git's SSH-tunneled transport. */
1001static void fill_ssh_args(struct child_process *conn, const char *ssh_host,
1002                          const char *port, int flags)
1003{
1004        const char *ssh;
1005        enum ssh_variant variant;
1006
1007        if (looks_like_command_line_option(ssh_host))
1008                die("strange hostname '%s' blocked", ssh_host);
1009
1010        ssh = get_ssh_command();
1011        if (ssh) {
1012                variant = determine_ssh_variant(ssh, 1);
1013        } else {
1014                /*
1015                 * GIT_SSH is the no-shell version of
1016                 * GIT_SSH_COMMAND (and must remain so for
1017                 * historical compatibility).
1018                 */
1019                conn->use_shell = 0;
1020
1021                ssh = getenv("GIT_SSH");
1022                if (!ssh)
1023                        ssh = "ssh";
1024                variant = determine_ssh_variant(ssh, 0);
1025        }
1026
1027        if (variant == VARIANT_AUTO) {
1028                struct child_process detect = CHILD_PROCESS_INIT;
1029
1030                detect.use_shell = conn->use_shell;
1031                detect.no_stdin = detect.no_stdout = detect.no_stderr = 1;
1032
1033                argv_array_push(&detect.args, ssh);
1034                argv_array_push(&detect.args, "-G");
1035                push_ssh_options(&detect.args, &detect.env_array,
1036                                 VARIANT_SSH, port, flags);
1037                argv_array_push(&detect.args, ssh_host);
1038
1039                variant = run_command(&detect) ? VARIANT_SIMPLE : VARIANT_SSH;
1040        }
1041
1042        argv_array_push(&conn->args, ssh);
1043        push_ssh_options(&conn->args, &conn->env_array, variant, port, flags);
1044        argv_array_push(&conn->args, ssh_host);
1045}
1046
1047/*
1048 * This returns the dummy child_process `no_fork` if the transport protocol
1049 * does not need fork(2), or a struct child_process object if it does.  Once
1050 * done, finish the connection with finish_connect() with the value returned
1051 * from this function (it is safe to call finish_connect() with NULL to
1052 * support the former case).
1053 *
1054 * If it returns, the connect is successful; it just dies on errors (this
1055 * will hopefully be changed in a libification effort, to return NULL when
1056 * the connection failed).
1057 */
1058struct child_process *git_connect(int fd[2], const char *url,
1059                                  const char *prog, int flags)
1060{
1061        char *hostandport, *path;
1062        struct child_process *conn;
1063        enum protocol protocol;
1064
1065        /* Without this we cannot rely on waitpid() to tell
1066         * what happened to our children.
1067         */
1068        signal(SIGCHLD, SIG_DFL);
1069
1070        protocol = parse_connect_url(url, &hostandport, &path);
1071        if ((flags & CONNECT_DIAG_URL) && (protocol != PROTO_SSH)) {
1072                printf("Diag: url=%s\n", url ? url : "NULL");
1073                printf("Diag: protocol=%s\n", prot_name(protocol));
1074                printf("Diag: hostandport=%s\n", hostandport ? hostandport : "NULL");
1075                printf("Diag: path=%s\n", path ? path : "NULL");
1076                conn = NULL;
1077        } else if (protocol == PROTO_GIT) {
1078                conn = git_connect_git(fd, hostandport, path, prog, flags);
1079        } else {
1080                struct strbuf cmd = STRBUF_INIT;
1081                const char *const *var;
1082
1083                conn = xmalloc(sizeof(*conn));
1084                child_process_init(conn);
1085
1086                if (looks_like_command_line_option(path))
1087                        die("strange pathname '%s' blocked", path);
1088
1089                strbuf_addstr(&cmd, prog);
1090                strbuf_addch(&cmd, ' ');
1091                sq_quote_buf(&cmd, path);
1092
1093                /* remove repo-local variables from the environment */
1094                for (var = local_repo_env; *var; var++)
1095                        argv_array_push(&conn->env_array, *var);
1096
1097                conn->use_shell = 1;
1098                conn->in = conn->out = -1;
1099                if (protocol == PROTO_SSH) {
1100                        char *ssh_host = hostandport;
1101                        const char *port = NULL;
1102                        transport_check_allowed("ssh");
1103                        get_host_and_port(&ssh_host, &port);
1104
1105                        if (!port)
1106                                port = get_port(ssh_host);
1107
1108                        if (flags & CONNECT_DIAG_URL) {
1109                                printf("Diag: url=%s\n", url ? url : "NULL");
1110                                printf("Diag: protocol=%s\n", prot_name(protocol));
1111                                printf("Diag: userandhost=%s\n", ssh_host ? ssh_host : "NULL");
1112                                printf("Diag: port=%s\n", port ? port : "NONE");
1113                                printf("Diag: path=%s\n", path ? path : "NULL");
1114
1115                                free(hostandport);
1116                                free(path);
1117                                free(conn);
1118                                strbuf_release(&cmd);
1119                                return NULL;
1120                        }
1121                        fill_ssh_args(conn, ssh_host, port, flags);
1122                } else {
1123                        transport_check_allowed("file");
1124                        if (get_protocol_version_config() > 0) {
1125                                argv_array_pushf(&conn->env_array, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
1126                                                 get_protocol_version_config());
1127                        }
1128                }
1129                argv_array_push(&conn->args, cmd.buf);
1130
1131                if (start_command(conn))
1132                        die("unable to fork");
1133
1134                fd[0] = conn->out; /* read from child's stdout */
1135                fd[1] = conn->in;  /* write to child's stdin */
1136                strbuf_release(&cmd);
1137        }
1138        free(hostandport);
1139        free(path);
1140        return conn;
1141}
1142
1143int finish_connect(struct child_process *conn)
1144{
1145        int code;
1146        if (!conn || git_connection_is_socket(conn))
1147                return 0;
1148
1149        code = finish_command(conn);
1150        free(conn);
1151        return code;
1152}