Andrew's git / gitweb.git / connect.c
?
connect.con commit connect: convert get_remote_heads to use struct packet_reader (7e3e479)
   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
  65static enum protocol_version discover_version(struct packet_reader *reader)
  66{
  67        enum protocol_version version = protocol_unknown_version;
  68
  69        /*
  70         * Peek the first line of the server's response to
  71         * determine the protocol version the server is speaking.
  72         */
  73        switch (packet_reader_peek(reader)) {
  74        case PACKET_READ_EOF:
  75                die_initial_contact(0);
  76        case PACKET_READ_FLUSH:
  77        case PACKET_READ_DELIM:
  78                version = protocol_v0;
  79                break;
  80        case PACKET_READ_NORMAL:
  81                version = determine_protocol_version_client(reader->line);
  82                break;
  83        }
  84
  85        switch (version) {
  86        case protocol_v1:
  87                /* Read the peeked version line */
  88                packet_reader_read(reader);
  89                break;
  90        case protocol_v0:
  91                break;
  92        case protocol_unknown_version:
  93                BUG("unknown protocol version");
  94        }
  95
  96        return version;
  97}
  98
  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(int in, char *src_buf, size_t src_len,
 237                              struct ref **list, unsigned int flags,
 238                              struct oid_array *extra_have,
 239                              struct oid_array *shallow_points)
 240{
 241        struct ref **orig_list = list;
 242        int len = 0;
 243        enum get_remote_heads_state state = EXPECTING_FIRST_REF;
 244        struct packet_reader reader;
 245        const char *arg;
 246
 247        packet_reader_init(&reader, in, src_buf, src_len,
 248                           PACKET_READ_CHOMP_NEWLINE |
 249                           PACKET_READ_GENTLE_ON_EOF);
 250
 251        discover_version(&reader);
 252
 253        *list = NULL;
 254
 255        while (state != EXPECTING_DONE) {
 256                switch (packet_reader_read(&reader)) {
 257                case PACKET_READ_EOF:
 258                        die_initial_contact(1);
 259                case PACKET_READ_NORMAL:
 260                        len = reader.pktlen;
 261                        if (len > 4 && skip_prefix(reader.line, "ERR ", &arg))
 262                                die("remote error: %s", arg);
 263                        break;
 264                case PACKET_READ_FLUSH:
 265                        state = EXPECTING_DONE;
 266                        break;
 267                case PACKET_READ_DELIM:
 268                        die("invalid packet");
 269                }
 270
 271                switch (state) {
 272                case EXPECTING_FIRST_REF:
 273                        process_capabilities(reader.line, &len);
 274                        if (process_dummy_ref(reader.line)) {
 275                                state = EXPECTING_SHALLOW;
 276                                break;
 277                        }
 278                        state = EXPECTING_REF;
 279                        /* fallthrough */
 280                case EXPECTING_REF:
 281                        if (process_ref(reader.line, len, &list, flags, extra_have))
 282                                break;
 283                        state = EXPECTING_SHALLOW;
 284                        /* fallthrough */
 285                case EXPECTING_SHALLOW:
 286                        if (process_shallow(reader.line, len, shallow_points))
 287                                break;
 288                        die("protocol error: unexpected '%s'", reader.line);
 289                case EXPECTING_DONE:
 290                        break;
 291                }
 292        }
 293
 294        annotate_refs_with_symref_info(*orig_list);
 295
 296        return list;
 297}
 298
 299static const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
 300{
 301        int len;
 302
 303        if (!feature_list)
 304                return NULL;
 305
 306        len = strlen(feature);
 307        while (*feature_list) {
 308                const char *found = strstr(feature_list, feature);
 309                if (!found)
 310                        return NULL;
 311                if (feature_list == found || isspace(found[-1])) {
 312                        const char *value = found + len;
 313                        /* feature with no value (e.g., "thin-pack") */
 314                        if (!*value || isspace(*value)) {
 315                                if (lenp)
 316                                        *lenp = 0;
 317                                return value;
 318                        }
 319                        /* feature with a value (e.g., "agent=git/1.2.3") */
 320                        else if (*value == '=') {
 321                                value++;
 322                                if (lenp)
 323                                        *lenp = strcspn(value, " \t\n");
 324                                return value;
 325                        }
 326                        /*
 327                         * otherwise we matched a substring of another feature;
 328                         * keep looking
 329                         */
 330                }
 331                feature_list = found + 1;
 332        }
 333        return NULL;
 334}
 335
 336int parse_feature_request(const char *feature_list, const char *feature)
 337{
 338        return !!parse_feature_value(feature_list, feature, NULL);
 339}
 340
 341const char *server_feature_value(const char *feature, int *len)
 342{
 343        return parse_feature_value(server_capabilities, feature, len);
 344}
 345
 346int server_supports(const char *feature)
 347{
 348        return !!server_feature_value(feature, NULL);
 349}
 350
 351enum protocol {
 352        PROTO_LOCAL = 1,
 353        PROTO_FILE,
 354        PROTO_SSH,
 355        PROTO_GIT
 356};
 357
 358int url_is_local_not_ssh(const char *url)
 359{
 360        const char *colon = strchr(url, ':');
 361        const char *slash = strchr(url, '/');
 362        return !colon || (slash && slash < colon) ||
 363                has_dos_drive_prefix(url);
 364}
 365
 366static const char *prot_name(enum protocol protocol)
 367{
 368        switch (protocol) {
 369                case PROTO_LOCAL:
 370                case PROTO_FILE:
 371                        return "file";
 372                case PROTO_SSH:
 373                        return "ssh";
 374                case PROTO_GIT:
 375                        return "git";
 376                default:
 377                        return "unknown protocol";
 378        }
 379}
 380
 381static enum protocol get_protocol(const char *name)
 382{
 383        if (!strcmp(name, "ssh"))
 384                return PROTO_SSH;
 385        if (!strcmp(name, "git"))
 386                return PROTO_GIT;
 387        if (!strcmp(name, "git+ssh")) /* deprecated - do not use */
 388                return PROTO_SSH;
 389        if (!strcmp(name, "ssh+git")) /* deprecated - do not use */
 390                return PROTO_SSH;
 391        if (!strcmp(name, "file"))
 392                return PROTO_FILE;
 393        die("I don't handle protocol '%s'", name);
 394}
 395
 396static char *host_end(char **hoststart, int removebrackets)
 397{
 398        char *host = *hoststart;
 399        char *end;
 400        char *start = strstr(host, "@[");
 401        if (start)
 402                start++; /* Jump over '@' */
 403        else
 404                start = host;
 405        if (start[0] == '[') {
 406                end = strchr(start + 1, ']');
 407                if (end) {
 408                        if (removebrackets) {
 409                                *end = 0;
 410                                memmove(start, start + 1, end - start);
 411                                end++;
 412                        }
 413                } else
 414                        end = host;
 415        } else
 416                end = host;
 417        return end;
 418}
 419
 420#define STR_(s) # s
 421#define STR(s)  STR_(s)
 422
 423static void get_host_and_port(char **host, const char **port)
 424{
 425        char *colon, *end;
 426        end = host_end(host, 1);
 427        colon = strchr(end, ':');
 428        if (colon) {
 429                long portnr = strtol(colon + 1, &end, 10);
 430                if (end != colon + 1 && *end == '\0' && 0 <= portnr && portnr < 65536) {
 431                        *colon = 0;
 432                        *port = colon + 1;
 433                } else if (!colon[1]) {
 434                        *colon = 0;
 435                }
 436        }
 437}
 438
 439static void enable_keepalive(int sockfd)
 440{
 441        int ka = 1;
 442
 443        if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
 444                fprintf(stderr, "unable to set SO_KEEPALIVE on socket: %s\n",
 445                        strerror(errno));
 446}
 447
 448#ifndef NO_IPV6
 449
 450static const char *ai_name(const struct addrinfo *ai)
 451{
 452        static char addr[NI_MAXHOST];
 453        if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
 454                        NI_NUMERICHOST) != 0)
 455                xsnprintf(addr, sizeof(addr), "(unknown)");
 456
 457        return addr;
 458}
 459
 460/*
 461 * Returns a connected socket() fd, or else die()s.
 462 */
 463static int git_tcp_connect_sock(char *host, int flags)
 464{
 465        struct strbuf error_message = STRBUF_INIT;
 466        int sockfd = -1;
 467        const char *port = STR(DEFAULT_GIT_PORT);
 468        struct addrinfo hints, *ai0, *ai;
 469        int gai;
 470        int cnt = 0;
 471
 472        get_host_and_port(&host, &port);
 473        if (!*port)
 474                port = "<none>";
 475
 476        memset(&hints, 0, sizeof(hints));
 477        if (flags & CONNECT_IPV4)
 478                hints.ai_family = AF_INET;
 479        else if (flags & CONNECT_IPV6)
 480                hints.ai_family = AF_INET6;
 481        hints.ai_socktype = SOCK_STREAM;
 482        hints.ai_protocol = IPPROTO_TCP;
 483
 484        if (flags & CONNECT_VERBOSE)
 485                fprintf(stderr, "Looking up %s ... ", host);
 486
 487        gai = getaddrinfo(host, port, &hints, &ai);
 488        if (gai)
 489                die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
 490
 491        if (flags & CONNECT_VERBOSE)
 492                fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 493
 494        for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
 495                sockfd = socket(ai->ai_family,
 496                                ai->ai_socktype, ai->ai_protocol);
 497                if ((sockfd < 0) ||
 498                    (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
 499                        strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 500                                    host, cnt, ai_name(ai), strerror(errno));
 501                        if (0 <= sockfd)
 502                                close(sockfd);
 503                        sockfd = -1;
 504                        continue;
 505                }
 506                if (flags & CONNECT_VERBOSE)
 507                        fprintf(stderr, "%s ", ai_name(ai));
 508                break;
 509        }
 510
 511        freeaddrinfo(ai0);
 512
 513        if (sockfd < 0)
 514                die("unable to connect to %s:\n%s", host, error_message.buf);
 515
 516        enable_keepalive(sockfd);
 517
 518        if (flags & CONNECT_VERBOSE)
 519                fprintf(stderr, "done.\n");
 520
 521        strbuf_release(&error_message);
 522
 523        return sockfd;
 524}
 525
 526#else /* NO_IPV6 */
 527
 528/*
 529 * Returns a connected socket() fd, or else die()s.
 530 */
 531static int git_tcp_connect_sock(char *host, int flags)
 532{
 533        struct strbuf error_message = STRBUF_INIT;
 534        int sockfd = -1;
 535        const char *port = STR(DEFAULT_GIT_PORT);
 536        char *ep;
 537        struct hostent *he;
 538        struct sockaddr_in sa;
 539        char **ap;
 540        unsigned int nport;
 541        int cnt;
 542
 543        get_host_and_port(&host, &port);
 544
 545        if (flags & CONNECT_VERBOSE)
 546                fprintf(stderr, "Looking up %s ... ", host);
 547
 548        he = gethostbyname(host);
 549        if (!he)
 550                die("Unable to look up %s (%s)", host, hstrerror(h_errno));
 551        nport = strtoul(port, &ep, 10);
 552        if ( ep == port || *ep ) {
 553                /* Not numeric */
 554                struct servent *se = getservbyname(port,"tcp");
 555                if ( !se )
 556                        die("Unknown port %s", port);
 557                nport = se->s_port;
 558        }
 559
 560        if (flags & CONNECT_VERBOSE)
 561                fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 562
 563        for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
 564                memset(&sa, 0, sizeof sa);
 565                sa.sin_family = he->h_addrtype;
 566                sa.sin_port = htons(nport);
 567                memcpy(&sa.sin_addr, *ap, he->h_length);
 568
 569                sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 570                if ((sockfd < 0) ||
 571                    connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 572                        strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 573                                host,
 574                                cnt,
 575                                inet_ntoa(*(struct in_addr *)&sa.sin_addr),
 576                                strerror(errno));
 577                        if (0 <= sockfd)
 578                                close(sockfd);
 579                        sockfd = -1;
 580                        continue;
 581                }
 582                if (flags & CONNECT_VERBOSE)
 583                        fprintf(stderr, "%s ",
 584                                inet_ntoa(*(struct in_addr *)&sa.sin_addr));
 585                break;
 586        }
 587
 588        if (sockfd < 0)
 589                die("unable to connect to %s:\n%s", host, error_message.buf);
 590
 591        enable_keepalive(sockfd);
 592
 593        if (flags & CONNECT_VERBOSE)
 594                fprintf(stderr, "done.\n");
 595
 596        return sockfd;
 597}
 598
 599#endif /* NO_IPV6 */
 600
 601
 602/*
 603 * Dummy child_process returned by git_connect() if the transport protocol
 604 * does not need fork(2).
 605 */
 606static struct child_process no_fork = CHILD_PROCESS_INIT;
 607
 608int git_connection_is_socket(struct child_process *conn)
 609{
 610        return conn == &no_fork;
 611}
 612
 613static struct child_process *git_tcp_connect(int fd[2], char *host, int flags)
 614{
 615        int sockfd = git_tcp_connect_sock(host, flags);
 616
 617        fd[0] = sockfd;
 618        fd[1] = dup(sockfd);
 619
 620        return &no_fork;
 621}
 622
 623
 624static char *git_proxy_command;
 625
 626static int git_proxy_command_options(const char *var, const char *value,
 627                void *cb)
 628{
 629        if (!strcmp(var, "core.gitproxy")) {
 630                const char *for_pos;
 631                int matchlen = -1;
 632                int hostlen;
 633                const char *rhost_name = cb;
 634                int rhost_len = strlen(rhost_name);
 635
 636                if (git_proxy_command)
 637                        return 0;
 638                if (!value)
 639                        return config_error_nonbool(var);
 640                /* [core]
 641                 * ;# matches www.kernel.org as well
 642                 * gitproxy = netcatter-1 for kernel.org
 643                 * gitproxy = netcatter-2 for sample.xz
 644                 * gitproxy = netcatter-default
 645                 */
 646                for_pos = strstr(value, " for ");
 647                if (!for_pos)
 648                        /* matches everybody */
 649                        matchlen = strlen(value);
 650                else {
 651                        hostlen = strlen(for_pos + 5);
 652                        if (rhost_len < hostlen)
 653                                matchlen = -1;
 654                        else if (!strncmp(for_pos + 5,
 655                                          rhost_name + rhost_len - hostlen,
 656                                          hostlen) &&
 657                                 ((rhost_len == hostlen) ||
 658                                  rhost_name[rhost_len - hostlen -1] == '.'))
 659                                matchlen = for_pos - value;
 660                        else
 661                                matchlen = -1;
 662                }
 663                if (0 <= matchlen) {
 664                        /* core.gitproxy = none for kernel.org */
 665                        if (matchlen == 4 &&
 666                            !memcmp(value, "none", 4))
 667                                matchlen = 0;
 668                        git_proxy_command = xmemdupz(value, matchlen);
 669                }
 670                return 0;
 671        }
 672
 673        return git_default_config(var, value, cb);
 674}
 675
 676static int git_use_proxy(const char *host)
 677{
 678        git_proxy_command = getenv("GIT_PROXY_COMMAND");
 679        git_config(git_proxy_command_options, (void*)host);
 680        return (git_proxy_command && *git_proxy_command);
 681}
 682
 683static struct child_process *git_proxy_connect(int fd[2], char *host)
 684{
 685        const char *port = STR(DEFAULT_GIT_PORT);
 686        struct child_process *proxy;
 687
 688        get_host_and_port(&host, &port);
 689
 690        if (looks_like_command_line_option(host))
 691                die("strange hostname '%s' blocked", host);
 692        if (looks_like_command_line_option(port))
 693                die("strange port '%s' blocked", port);
 694
 695        proxy = xmalloc(sizeof(*proxy));
 696        child_process_init(proxy);
 697        argv_array_push(&proxy->args, git_proxy_command);
 698        argv_array_push(&proxy->args, host);
 699        argv_array_push(&proxy->args, port);
 700        proxy->in = -1;
 701        proxy->out = -1;
 702        if (start_command(proxy))
 703                die("cannot start proxy %s", git_proxy_command);
 704        fd[0] = proxy->out; /* read from proxy stdout */
 705        fd[1] = proxy->in;  /* write to proxy stdin */
 706        return proxy;
 707}
 708
 709static char *get_port(char *host)
 710{
 711        char *end;
 712        char *p = strchr(host, ':');
 713
 714        if (p) {
 715                long port = strtol(p + 1, &end, 10);
 716                if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
 717                        *p = '\0';
 718                        return p+1;
 719                }
 720        }
 721
 722        return NULL;
 723}
 724
 725/*
 726 * Extract protocol and relevant parts from the specified connection URL.
 727 * The caller must free() the returned strings.
 728 */
 729static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
 730                                       char **ret_path)
 731{
 732        char *url;
 733        char *host, *path;
 734        char *end;
 735        int separator = '/';
 736        enum protocol protocol = PROTO_LOCAL;
 737
 738        if (is_url(url_orig))
 739                url = url_decode(url_orig);
 740        else
 741                url = xstrdup(url_orig);
 742
 743        host = strstr(url, "://");
 744        if (host) {
 745                *host = '\0';
 746                protocol = get_protocol(url);
 747                host += 3;
 748        } else {
 749                host = url;
 750                if (!url_is_local_not_ssh(url)) {
 751                        protocol = PROTO_SSH;
 752                        separator = ':';
 753                }
 754        }
 755
 756        /*
 757         * Don't do destructive transforms as protocol code does
 758         * '[]' unwrapping in get_host_and_port()
 759         */
 760        end = host_end(&host, 0);
 761
 762        if (protocol == PROTO_LOCAL)
 763                path = end;
 764        else if (protocol == PROTO_FILE && has_dos_drive_prefix(end))
 765                path = end; /* "file://$(pwd)" may be "file://C:/projects/repo" */
 766        else
 767                path = strchr(end, separator);
 768
 769        if (!path || !*path)
 770                die("No path specified. See 'man git-pull' for valid url syntax");
 771
 772        /*
 773         * null-terminate hostname and point path to ~ for URL's like this:
 774         *    ssh://host.xz/~user/repo
 775         */
 776
 777        end = path; /* Need to \0 terminate host here */
 778        if (separator == ':')
 779                path++; /* path starts after ':' */
 780        if (protocol == PROTO_GIT || protocol == PROTO_SSH) {
 781                if (path[1] == '~')
 782                        path++;
 783        }
 784
 785        path = xstrdup(path);
 786        *end = '\0';
 787
 788        *ret_host = xstrdup(host);
 789        *ret_path = path;
 790        free(url);
 791        return protocol;
 792}
 793
 794static const char *get_ssh_command(void)
 795{
 796        const char *ssh;
 797
 798        if ((ssh = getenv("GIT_SSH_COMMAND")))
 799                return ssh;
 800
 801        if (!git_config_get_string_const("core.sshcommand", &ssh))
 802                return ssh;
 803
 804        return NULL;
 805}
 806
 807enum ssh_variant {
 808        VARIANT_AUTO,
 809        VARIANT_SIMPLE,
 810        VARIANT_SSH,
 811        VARIANT_PLINK,
 812        VARIANT_PUTTY,
 813        VARIANT_TORTOISEPLINK,
 814};
 815
 816static void override_ssh_variant(enum ssh_variant *ssh_variant)
 817{
 818        const char *variant = getenv("GIT_SSH_VARIANT");
 819
 820        if (!variant && git_config_get_string_const("ssh.variant", &variant))
 821                return;
 822
 823        if (!strcmp(variant, "auto"))
 824                *ssh_variant = VARIANT_AUTO;
 825        else if (!strcmp(variant, "plink"))
 826                *ssh_variant = VARIANT_PLINK;
 827        else if (!strcmp(variant, "putty"))
 828                *ssh_variant = VARIANT_PUTTY;
 829        else if (!strcmp(variant, "tortoiseplink"))
 830                *ssh_variant = VARIANT_TORTOISEPLINK;
 831        else if (!strcmp(variant, "simple"))
 832                *ssh_variant = VARIANT_SIMPLE;
 833        else
 834                *ssh_variant = VARIANT_SSH;
 835}
 836
 837static enum ssh_variant determine_ssh_variant(const char *ssh_command,
 838                                              int is_cmdline)
 839{
 840        enum ssh_variant ssh_variant = VARIANT_AUTO;
 841        const char *variant;
 842        char *p = NULL;
 843
 844        override_ssh_variant(&ssh_variant);
 845
 846        if (ssh_variant != VARIANT_AUTO)
 847                return ssh_variant;
 848
 849        if (!is_cmdline) {
 850                p = xstrdup(ssh_command);
 851                variant = basename(p);
 852        } else {
 853                const char **ssh_argv;
 854
 855                p = xstrdup(ssh_command);
 856                if (split_cmdline(p, &ssh_argv) > 0) {
 857                        variant = basename((char *)ssh_argv[0]);
 858                        /*
 859                         * At this point, variant points into the buffer
 860                         * referenced by p, hence we do not need ssh_argv
 861                         * any longer.
 862                         */
 863                        free(ssh_argv);
 864                } else {
 865                        free(p);
 866                        return ssh_variant;
 867                }
 868        }
 869
 870        if (!strcasecmp(variant, "ssh") ||
 871            !strcasecmp(variant, "ssh.exe"))
 872                ssh_variant = VARIANT_SSH;
 873        else if (!strcasecmp(variant, "plink") ||
 874                 !strcasecmp(variant, "plink.exe"))
 875                ssh_variant = VARIANT_PLINK;
 876        else if (!strcasecmp(variant, "tortoiseplink") ||
 877                 !strcasecmp(variant, "tortoiseplink.exe"))
 878                ssh_variant = VARIANT_TORTOISEPLINK;
 879
 880        free(p);
 881        return ssh_variant;
 882}
 883
 884/*
 885 * Open a connection using Git's native protocol.
 886 *
 887 * The caller is responsible for freeing hostandport, but this function may
 888 * modify it (for example, to truncate it to remove the port part).
 889 */
 890static struct child_process *git_connect_git(int fd[2], char *hostandport,
 891                                             const char *path, const char *prog,
 892                                             int flags)
 893{
 894        struct child_process *conn;
 895        struct strbuf request = STRBUF_INIT;
 896        /*
 897         * Set up virtual host information based on where we will
 898         * connect, unless the user has overridden us in
 899         * the environment.
 900         */
 901        char *target_host = getenv("GIT_OVERRIDE_VIRTUAL_HOST");
 902        if (target_host)
 903                target_host = xstrdup(target_host);
 904        else
 905                target_host = xstrdup(hostandport);
 906
 907        transport_check_allowed("git");
 908
 909        /*
 910         * These underlying connection commands die() if they
 911         * cannot connect.
 912         */
 913        if (git_use_proxy(hostandport))
 914                conn = git_proxy_connect(fd, hostandport);
 915        else
 916                conn = git_tcp_connect(fd, hostandport, flags);
 917        /*
 918         * Separate original protocol components prog and path
 919         * from extended host header with a NUL byte.
 920         *
 921         * Note: Do not add any other headers here!  Doing so
 922         * will cause older git-daemon servers to crash.
 923         */
 924        strbuf_addf(&request,
 925                    "%s %s%chost=%s%c",
 926                    prog, path, 0,
 927                    target_host, 0);
 928
 929        /* If using a new version put that stuff here after a second null byte */
 930        if (get_protocol_version_config() > 0) {
 931                strbuf_addch(&request, '\0');
 932                strbuf_addf(&request, "version=%d%c",
 933                            get_protocol_version_config(), '\0');
 934        }
 935
 936        packet_write(fd[1], request.buf, request.len);
 937
 938        free(target_host);
 939        strbuf_release(&request);
 940        return conn;
 941}
 942
 943/*
 944 * Append the appropriate environment variables to `env` and options to
 945 * `args` for running ssh in Git's SSH-tunneled transport.
 946 */
 947static void push_ssh_options(struct argv_array *args, struct argv_array *env,
 948                             enum ssh_variant variant, const char *port,
 949                             int flags)
 950{
 951        if (variant == VARIANT_SSH &&
 952            get_protocol_version_config() > 0) {
 953                argv_array_push(args, "-o");
 954                argv_array_push(args, "SendEnv=" GIT_PROTOCOL_ENVIRONMENT);
 955                argv_array_pushf(env, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
 956                                 get_protocol_version_config());
 957        }
 958
 959        if (flags & CONNECT_IPV4) {
 960                switch (variant) {
 961                case VARIANT_AUTO:
 962                        BUG("VARIANT_AUTO passed to push_ssh_options");
 963                case VARIANT_SIMPLE:
 964                        die("ssh variant 'simple' does not support -4");
 965                case VARIANT_SSH:
 966                case VARIANT_PLINK:
 967                case VARIANT_PUTTY:
 968                case VARIANT_TORTOISEPLINK:
 969                        argv_array_push(args, "-4");
 970                }
 971        } else if (flags & CONNECT_IPV6) {
 972                switch (variant) {
 973                case VARIANT_AUTO:
 974                        BUG("VARIANT_AUTO passed to push_ssh_options");
 975                case VARIANT_SIMPLE:
 976                        die("ssh variant 'simple' does not support -6");
 977                case VARIANT_SSH:
 978                case VARIANT_PLINK:
 979                case VARIANT_PUTTY:
 980                case VARIANT_TORTOISEPLINK:
 981                        argv_array_push(args, "-6");
 982                }
 983        }
 984
 985        if (variant == VARIANT_TORTOISEPLINK)
 986                argv_array_push(args, "-batch");
 987
 988        if (port) {
 989                switch (variant) {
 990                case VARIANT_AUTO:
 991                        BUG("VARIANT_AUTO passed to push_ssh_options");
 992                case VARIANT_SIMPLE:
 993                        die("ssh variant 'simple' does not support setting port");
 994                case VARIANT_SSH:
 995                        argv_array_push(args, "-p");
 996                        break;
 997                case VARIANT_PLINK:
 998                case VARIANT_PUTTY:
 999                case VARIANT_TORTOISEPLINK:
1000                        argv_array_push(args, "-P");
1001                }
1002
1003                argv_array_push(args, port);
1004        }
1005}
1006
1007/* Prepare a child_process for use by Git's SSH-tunneled transport. */
1008static void fill_ssh_args(struct child_process *conn, const char *ssh_host,
1009                          const char *port, int flags)
1010{
1011        const char *ssh;
1012        enum ssh_variant variant;
1013
1014        if (looks_like_command_line_option(ssh_host))
1015                die("strange hostname '%s' blocked", ssh_host);
1016
1017        ssh = get_ssh_command();
1018        if (ssh) {
1019                variant = determine_ssh_variant(ssh, 1);
1020        } else {
1021                /*
1022                 * GIT_SSH is the no-shell version of
1023                 * GIT_SSH_COMMAND (and must remain so for
1024                 * historical compatibility).
1025                 */
1026                conn->use_shell = 0;
1027
1028                ssh = getenv("GIT_SSH");
1029                if (!ssh)
1030                        ssh = "ssh";
1031                variant = determine_ssh_variant(ssh, 0);
1032        }
1033
1034        if (variant == VARIANT_AUTO) {
1035                struct child_process detect = CHILD_PROCESS_INIT;
1036
1037                detect.use_shell = conn->use_shell;
1038                detect.no_stdin = detect.no_stdout = detect.no_stderr = 1;
1039
1040                argv_array_push(&detect.args, ssh);
1041                argv_array_push(&detect.args, "-G");
1042                push_ssh_options(&detect.args, &detect.env_array,
1043                                 VARIANT_SSH, port, flags);
1044                argv_array_push(&detect.args, ssh_host);
1045
1046                variant = run_command(&detect) ? VARIANT_SIMPLE : VARIANT_SSH;
1047        }
1048
1049        argv_array_push(&conn->args, ssh);
1050        push_ssh_options(&conn->args, &conn->env_array, variant, port, flags);
1051        argv_array_push(&conn->args, ssh_host);
1052}
1053
1054/*
1055 * This returns the dummy child_process `no_fork` if the transport protocol
1056 * does not need fork(2), or a struct child_process object if it does.  Once
1057 * done, finish the connection with finish_connect() with the value returned
1058 * from this function (it is safe to call finish_connect() with NULL to
1059 * support the former case).
1060 *
1061 * If it returns, the connect is successful; it just dies on errors (this
1062 * will hopefully be changed in a libification effort, to return NULL when
1063 * the connection failed).
1064 */
1065struct child_process *git_connect(int fd[2], const char *url,
1066                                  const char *prog, int flags)
1067{
1068        char *hostandport, *path;
1069        struct child_process *conn;
1070        enum protocol protocol;
1071
1072        /* Without this we cannot rely on waitpid() to tell
1073         * what happened to our children.
1074         */
1075        signal(SIGCHLD, SIG_DFL);
1076
1077        protocol = parse_connect_url(url, &hostandport, &path);
1078        if ((flags & CONNECT_DIAG_URL) && (protocol != PROTO_SSH)) {
1079                printf("Diag: url=%s\n", url ? url : "NULL");
1080                printf("Diag: protocol=%s\n", prot_name(protocol));
1081                printf("Diag: hostandport=%s\n", hostandport ? hostandport : "NULL");
1082                printf("Diag: path=%s\n", path ? path : "NULL");
1083                conn = NULL;
1084        } else if (protocol == PROTO_GIT) {
1085                conn = git_connect_git(fd, hostandport, path, prog, flags);
1086        } else {
1087                struct strbuf cmd = STRBUF_INIT;
1088                const char *const *var;
1089
1090                conn = xmalloc(sizeof(*conn));
1091                child_process_init(conn);
1092
1093                if (looks_like_command_line_option(path))
1094                        die("strange pathname '%s' blocked", path);
1095
1096                strbuf_addstr(&cmd, prog);
1097                strbuf_addch(&cmd, ' ');
1098                sq_quote_buf(&cmd, path);
1099
1100                /* remove repo-local variables from the environment */
1101                for (var = local_repo_env; *var; var++)
1102                        argv_array_push(&conn->env_array, *var);
1103
1104                conn->use_shell = 1;
1105                conn->in = conn->out = -1;
1106                if (protocol == PROTO_SSH) {
1107                        char *ssh_host = hostandport;
1108                        const char *port = NULL;
1109                        transport_check_allowed("ssh");
1110                        get_host_and_port(&ssh_host, &port);
1111
1112                        if (!port)
1113                                port = get_port(ssh_host);
1114
1115                        if (flags & CONNECT_DIAG_URL) {
1116                                printf("Diag: url=%s\n", url ? url : "NULL");
1117                                printf("Diag: protocol=%s\n", prot_name(protocol));
1118                                printf("Diag: userandhost=%s\n", ssh_host ? ssh_host : "NULL");
1119                                printf("Diag: port=%s\n", port ? port : "NONE");
1120                                printf("Diag: path=%s\n", path ? path : "NULL");
1121
1122                                free(hostandport);
1123                                free(path);
1124                                free(conn);
1125                                strbuf_release(&cmd);
1126                                return NULL;
1127                        }
1128                        fill_ssh_args(conn, ssh_host, port, flags);
1129                } else {
1130                        transport_check_allowed("file");
1131                        if (get_protocol_version_config() > 0) {
1132                                argv_array_pushf(&conn->env_array, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
1133                                                 get_protocol_version_config());
1134                        }
1135                }
1136                argv_array_push(&conn->args, cmd.buf);
1137
1138                if (start_command(conn))
1139                        die("unable to fork");
1140
1141                fd[0] = conn->out; /* read from child's stdout */
1142                fd[1] = conn->in;  /* write to child's stdin */
1143                strbuf_release(&cmd);
1144        }
1145        free(hostandport);
1146        free(path);
1147        return conn;
1148}
1149
1150int finish_connect(struct child_process *conn)
1151{
1152        int code;
1153        if (!conn || git_connection_is_socket(conn))
1154                return 0;
1155
1156        code = finish_command(conn);
1157        free(conn);
1158        return code;
1159}