Andrew's git / gitweb.git / connect.c
?
connect.con commit i5700: add interop test for protocol transition (3c88ebd)
   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        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
  59static 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;
  80reject:
  81        free(sym);
  82        return;
  83}
  84
  85static 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 */
 115static 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. */
 139static 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
 151static 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
 160static 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
 174static 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
 181static 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
 207static 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 */
 227struct 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
 282static 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
 319int parse_feature_request(const char *feature_list, const char *feature)
 320{
 321        return !!parse_feature_value(feature_list, feature, NULL);
 322}
 323
 324const char *server_feature_value(const char *feature, int *len)
 325{
 326        return parse_feature_value(server_capabilities, feature, len);
 327}
 328
 329int server_supports(const char *feature)
 330{
 331        return !!server_feature_value(feature, NULL);
 332}
 333
 334enum protocol {
 335        PROTO_LOCAL = 1,
 336        PROTO_FILE,
 337        PROTO_SSH,
 338        PROTO_GIT
 339};
 340
 341int 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
 349static 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
 364static 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
 379static 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
 406static 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
 422static 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
 433static 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 */
 446static 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 */
 514static 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
 585static void git_tcp_connect(int fd[2], char *host, int flags)
 586{
 587        int sockfd = git_tcp_connect_sock(host, flags);
 588
 589        fd[0] = sockfd;
 590        fd[1] = dup(sockfd);
 591}
 592
 593
 594static char *git_proxy_command;
 595
 596static int git_proxy_command_options(const char *var, const char *value,
 597                void *cb)
 598{
 599        if (!strcmp(var, "core.gitproxy")) {
 600                const char *for_pos;
 601                int matchlen = -1;
 602                int hostlen;
 603                const char *rhost_name = cb;
 604                int rhost_len = strlen(rhost_name);
 605
 606                if (git_proxy_command)
 607                        return 0;
 608                if (!value)
 609                        return config_error_nonbool(var);
 610                /* [core]
 611                 * ;# matches www.kernel.org as well
 612                 * gitproxy = netcatter-1 for kernel.org
 613                 * gitproxy = netcatter-2 for sample.xz
 614                 * gitproxy = netcatter-default
 615                 */
 616                for_pos = strstr(value, " for ");
 617                if (!for_pos)
 618                        /* matches everybody */
 619                        matchlen = strlen(value);
 620                else {
 621                        hostlen = strlen(for_pos + 5);
 622                        if (rhost_len < hostlen)
 623                                matchlen = -1;
 624                        else if (!strncmp(for_pos + 5,
 625                                          rhost_name + rhost_len - hostlen,
 626                                          hostlen) &&
 627                                 ((rhost_len == hostlen) ||
 628                                  rhost_name[rhost_len - hostlen -1] == '.'))
 629                                matchlen = for_pos - value;
 630                        else
 631                                matchlen = -1;
 632                }
 633                if (0 <= matchlen) {
 634                        /* core.gitproxy = none for kernel.org */
 635                        if (matchlen == 4 &&
 636                            !memcmp(value, "none", 4))
 637                                matchlen = 0;
 638                        git_proxy_command = xmemdupz(value, matchlen);
 639                }
 640                return 0;
 641        }
 642
 643        return git_default_config(var, value, cb);
 644}
 645
 646static int git_use_proxy(const char *host)
 647{
 648        git_proxy_command = getenv("GIT_PROXY_COMMAND");
 649        git_config(git_proxy_command_options, (void*)host);
 650        return (git_proxy_command && *git_proxy_command);
 651}
 652
 653static struct child_process *git_proxy_connect(int fd[2], char *host)
 654{
 655        const char *port = STR(DEFAULT_GIT_PORT);
 656        struct child_process *proxy;
 657
 658        get_host_and_port(&host, &port);
 659
 660        if (looks_like_command_line_option(host))
 661                die("strange hostname '%s' blocked", host);
 662        if (looks_like_command_line_option(port))
 663                die("strange port '%s' blocked", port);
 664
 665        proxy = xmalloc(sizeof(*proxy));
 666        child_process_init(proxy);
 667        argv_array_push(&proxy->args, git_proxy_command);
 668        argv_array_push(&proxy->args, host);
 669        argv_array_push(&proxy->args, port);
 670        proxy->in = -1;
 671        proxy->out = -1;
 672        if (start_command(proxy))
 673                die("cannot start proxy %s", git_proxy_command);
 674        fd[0] = proxy->out; /* read from proxy stdout */
 675        fd[1] = proxy->in;  /* write to proxy stdin */
 676        return proxy;
 677}
 678
 679static char *get_port(char *host)
 680{
 681        char *end;
 682        char *p = strchr(host, ':');
 683
 684        if (p) {
 685                long port = strtol(p + 1, &end, 10);
 686                if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
 687                        *p = '\0';
 688                        return p+1;
 689                }
 690        }
 691
 692        return NULL;
 693}
 694
 695/*
 696 * Extract protocol and relevant parts from the specified connection URL.
 697 * The caller must free() the returned strings.
 698 */
 699static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
 700                                       char **ret_path)
 701{
 702        char *url;
 703        char *host, *path;
 704        char *end;
 705        int separator = '/';
 706        enum protocol protocol = PROTO_LOCAL;
 707
 708        if (is_url(url_orig))
 709                url = url_decode(url_orig);
 710        else
 711                url = xstrdup(url_orig);
 712
 713        host = strstr(url, "://");
 714        if (host) {
 715                *host = '\0';
 716                protocol = get_protocol(url);
 717                host += 3;
 718        } else {
 719                host = url;
 720                if (!url_is_local_not_ssh(url)) {
 721                        protocol = PROTO_SSH;
 722                        separator = ':';
 723                }
 724        }
 725
 726        /*
 727         * Don't do destructive transforms as protocol code does
 728         * '[]' unwrapping in get_host_and_port()
 729         */
 730        end = host_end(&host, 0);
 731
 732        if (protocol == PROTO_LOCAL)
 733                path = end;
 734        else if (protocol == PROTO_FILE && has_dos_drive_prefix(end))
 735                path = end; /* "file://$(pwd)" may be "file://C:/projects/repo" */
 736        else
 737                path = strchr(end, separator);
 738
 739        if (!path || !*path)
 740                die("No path specified. See 'man git-pull' for valid url syntax");
 741
 742        /*
 743         * null-terminate hostname and point path to ~ for URL's like this:
 744         *    ssh://host.xz/~user/repo
 745         */
 746
 747        end = path; /* Need to \0 terminate host here */
 748        if (separator == ':')
 749                path++; /* path starts after ':' */
 750        if (protocol == PROTO_GIT || protocol == PROTO_SSH) {
 751                if (path[1] == '~')
 752                        path++;
 753        }
 754
 755        path = xstrdup(path);
 756        *end = '\0';
 757
 758        *ret_host = xstrdup(host);
 759        *ret_path = path;
 760        free(url);
 761        return protocol;
 762}
 763
 764static struct child_process no_fork = CHILD_PROCESS_INIT;
 765
 766static const char *get_ssh_command(void)
 767{
 768        const char *ssh;
 769
 770        if ((ssh = getenv("GIT_SSH_COMMAND")))
 771                return ssh;
 772
 773        if (!git_config_get_string_const("core.sshcommand", &ssh))
 774                return ssh;
 775
 776        return NULL;
 777}
 778
 779static int override_ssh_variant(int *port_option, int *needs_batch)
 780{
 781        char *variant;
 782
 783        variant = xstrdup_or_null(getenv("GIT_SSH_VARIANT"));
 784        if (!variant &&
 785            git_config_get_string("ssh.variant", &variant))
 786                return 0;
 787
 788        if (!strcmp(variant, "plink") || !strcmp(variant, "putty")) {
 789                *port_option = 'P';
 790                *needs_batch = 0;
 791        } else if (!strcmp(variant, "tortoiseplink")) {
 792                *port_option = 'P';
 793                *needs_batch = 1;
 794        } else {
 795                *port_option = 'p';
 796                *needs_batch = 0;
 797        }
 798        free(variant);
 799        return 1;
 800}
 801
 802static void handle_ssh_variant(const char *ssh_command, int is_cmdline,
 803                               int *port_option, int *needs_batch)
 804{
 805        const char *variant;
 806        char *p = NULL;
 807
 808        if (override_ssh_variant(port_option, needs_batch))
 809                return;
 810
 811        if (!is_cmdline) {
 812                p = xstrdup(ssh_command);
 813                variant = basename(p);
 814        } else {
 815                const char **ssh_argv;
 816
 817                p = xstrdup(ssh_command);
 818                if (split_cmdline(p, &ssh_argv) > 0) {
 819                        variant = basename((char *)ssh_argv[0]);
 820                        /*
 821                         * At this point, variant points into the buffer
 822                         * referenced by p, hence we do not need ssh_argv
 823                         * any longer.
 824                         */
 825                        free(ssh_argv);
 826                } else {
 827                        free(p);
 828                        return;
 829                }
 830        }
 831
 832        if (!strcasecmp(variant, "plink") ||
 833            !strcasecmp(variant, "plink.exe"))
 834                *port_option = 'P';
 835        else if (!strcasecmp(variant, "tortoiseplink") ||
 836                 !strcasecmp(variant, "tortoiseplink.exe")) {
 837                *port_option = 'P';
 838                *needs_batch = 1;
 839        }
 840        free(p);
 841}
 842
 843/*
 844 * This returns a dummy child_process if the transport protocol does not
 845 * need fork(2), or a struct child_process object if it does.  Once done,
 846 * finish the connection with finish_connect() with the value returned from
 847 * this function (it is safe to call finish_connect() with NULL to support
 848 * the former case).
 849 *
 850 * If it returns, the connect is successful; it just dies on errors (this
 851 * will hopefully be changed in a libification effort, to return NULL when
 852 * the connection failed).
 853 */
 854struct child_process *git_connect(int fd[2], const char *url,
 855                                  const char *prog, int flags)
 856{
 857        char *hostandport, *path;
 858        struct child_process *conn = &no_fork;
 859        enum protocol protocol;
 860
 861        /* Without this we cannot rely on waitpid() to tell
 862         * what happened to our children.
 863         */
 864        signal(SIGCHLD, SIG_DFL);
 865
 866        protocol = parse_connect_url(url, &hostandport, &path);
 867        if ((flags & CONNECT_DIAG_URL) && (protocol != PROTO_SSH)) {
 868                printf("Diag: url=%s\n", url ? url : "NULL");
 869                printf("Diag: protocol=%s\n", prot_name(protocol));
 870                printf("Diag: hostandport=%s\n", hostandport ? hostandport : "NULL");
 871                printf("Diag: path=%s\n", path ? path : "NULL");
 872                conn = NULL;
 873        } else if (protocol == PROTO_GIT) {
 874                struct strbuf request = STRBUF_INIT;
 875                /*
 876                 * Set up virtual host information based on where we will
 877                 * connect, unless the user has overridden us in
 878                 * the environment.
 879                 */
 880                char *target_host = getenv("GIT_OVERRIDE_VIRTUAL_HOST");
 881                if (target_host)
 882                        target_host = xstrdup(target_host);
 883                else
 884                        target_host = xstrdup(hostandport);
 885
 886                transport_check_allowed("git");
 887
 888                /* These underlying connection commands die() if they
 889                 * cannot connect.
 890                 */
 891                if (git_use_proxy(hostandport))
 892                        conn = git_proxy_connect(fd, hostandport);
 893                else
 894                        git_tcp_connect(fd, hostandport, flags);
 895                /*
 896                 * Separate original protocol components prog and path
 897                 * from extended host header with a NUL byte.
 898                 *
 899                 * Note: Do not add any other headers here!  Doing so
 900                 * will cause older git-daemon servers to crash.
 901                 */
 902                strbuf_addf(&request,
 903                            "%s %s%chost=%s%c",
 904                            prog, path, 0,
 905                            target_host, 0);
 906
 907                /* If using a new version put that stuff here after a second null byte */
 908                if (get_protocol_version_config() > 0) {
 909                        strbuf_addch(&request, '\0');
 910                        strbuf_addf(&request, "version=%d%c",
 911                                    get_protocol_version_config(), '\0');
 912                }
 913
 914                packet_write(fd[1], request.buf, request.len);
 915
 916                free(target_host);
 917                strbuf_release(&request);
 918        } else {
 919                struct strbuf cmd = STRBUF_INIT;
 920                const char *const *var;
 921
 922                conn = xmalloc(sizeof(*conn));
 923                child_process_init(conn);
 924
 925                if (looks_like_command_line_option(path))
 926                        die("strange pathname '%s' blocked", path);
 927
 928                strbuf_addstr(&cmd, prog);
 929                strbuf_addch(&cmd, ' ');
 930                sq_quote_buf(&cmd, path);
 931
 932                /* remove repo-local variables from the environment */
 933                for (var = local_repo_env; *var; var++)
 934                        argv_array_push(&conn->env_array, *var);
 935
 936                conn->use_shell = 1;
 937                conn->in = conn->out = -1;
 938                if (protocol == PROTO_SSH) {
 939                        const char *ssh;
 940                        int needs_batch = 0;
 941                        int port_option = 'p';
 942                        char *ssh_host = hostandport;
 943                        const char *port = NULL;
 944                        transport_check_allowed("ssh");
 945                        get_host_and_port(&ssh_host, &port);
 946
 947                        if (!port)
 948                                port = get_port(ssh_host);
 949
 950                        if (flags & CONNECT_DIAG_URL) {
 951                                printf("Diag: url=%s\n", url ? url : "NULL");
 952                                printf("Diag: protocol=%s\n", prot_name(protocol));
 953                                printf("Diag: userandhost=%s\n", ssh_host ? ssh_host : "NULL");
 954                                printf("Diag: port=%s\n", port ? port : "NONE");
 955                                printf("Diag: path=%s\n", path ? path : "NULL");
 956
 957                                free(hostandport);
 958                                free(path);
 959                                free(conn);
 960                                strbuf_release(&cmd);
 961                                return NULL;
 962                        }
 963
 964                        if (looks_like_command_line_option(ssh_host))
 965                                die("strange hostname '%s' blocked", ssh_host);
 966
 967                        ssh = get_ssh_command();
 968                        if (ssh)
 969                                handle_ssh_variant(ssh, 1, &port_option,
 970                                                   &needs_batch);
 971                        else {
 972                                /*
 973                                 * GIT_SSH is the no-shell version of
 974                                 * GIT_SSH_COMMAND (and must remain so for
 975                                 * historical compatibility).
 976                                 */
 977                                conn->use_shell = 0;
 978
 979                                ssh = getenv("GIT_SSH");
 980                                if (!ssh)
 981                                        ssh = "ssh";
 982                                else
 983                                        handle_ssh_variant(ssh, 0,
 984                                                           &port_option,
 985                                                           &needs_batch);
 986                        }
 987
 988                        argv_array_push(&conn->args, ssh);
 989
 990                        if (get_protocol_version_config() > 0) {
 991                                argv_array_push(&conn->args, "-o");
 992                                argv_array_push(&conn->args, "SendEnv=" GIT_PROTOCOL_ENVIRONMENT);
 993                                argv_array_pushf(&conn->env_array, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
 994                                                 get_protocol_version_config());
 995                        }
 996
 997                        if (flags & CONNECT_IPV4)
 998                                argv_array_push(&conn->args, "-4");
 999                        else if (flags & CONNECT_IPV6)
1000                                argv_array_push(&conn->args, "-6");
1001                        if (needs_batch)
1002                                argv_array_push(&conn->args, "-batch");
1003                        if (port) {
1004                                argv_array_pushf(&conn->args,
1005                                                 "-%c", port_option);
1006                                argv_array_push(&conn->args, port);
1007                        }
1008                        argv_array_push(&conn->args, ssh_host);
1009                } else {
1010                        transport_check_allowed("file");
1011                        if (get_protocol_version_config() > 0) {
1012                                argv_array_pushf(&conn->env_array, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
1013                                                 get_protocol_version_config());
1014                        }
1015                }
1016                argv_array_push(&conn->args, cmd.buf);
1017
1018                if (start_command(conn))
1019                        die("unable to fork");
1020
1021                fd[0] = conn->out; /* read from child's stdout */
1022                fd[1] = conn->in;  /* write to child's stdin */
1023                strbuf_release(&cmd);
1024        }
1025        free(hostandport);
1026        free(path);
1027        return conn;
1028}
1029
1030int git_connection_is_socket(struct child_process *conn)
1031{
1032        return conn == &no_fork;
1033}
1034
1035int finish_connect(struct child_process *conn)
1036{
1037        int code;
1038        if (!conn || git_connection_is_socket(conn))
1039                return 0;
1040
1041        code = finish_command(conn);
1042        free(conn);
1043        return code;
1044}