connect.con commit Merge branch 'jc/mailinfo-cleanup-fix' into maint (bffce88)
   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
 585/*
 586 * Dummy child_process returned by git_connect() if the transport protocol
 587 * does not need fork(2).
 588 */
 589static struct child_process no_fork = CHILD_PROCESS_INIT;
 590
 591int git_connection_is_socket(struct child_process *conn)
 592{
 593        return conn == &no_fork;
 594}
 595
 596static 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
 607static char *git_proxy_command;
 608
 609static 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
 659static 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
 666static 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
 692static 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 */
 712static 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
 777static 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
 790enum ssh_variant {
 791        VARIANT_AUTO,
 792        VARIANT_SIMPLE,
 793        VARIANT_SSH,
 794        VARIANT_PLINK,
 795        VARIANT_PUTTY,
 796        VARIANT_TORTOISEPLINK,
 797};
 798
 799static 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
 820static 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 */
 873static 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 */
 930static 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. */
 991static 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 */
1048struct 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
1133int 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}