Andrew's git / gitweb.git / connect.c
?
connect.con commit config: fail if --get-urlmatch finds no value (27b30be)
   1#include "git-compat-util.h"
   2#include "cache.h"
   3#include "pkt-line.h"
   4#include "quote.h"
   5#include "refs.h"
   6#include "run-command.h"
   7#include "remote.h"
   8#include "connect.h"
   9#include "url.h"
  10#include "string-list.h"
  11#include "sha1-array.h"
  12#include "transport.h"
  13
  14static char *server_capabilities;
  15static const char *parse_feature_value(const char *, const char *, int *);
  16
  17static int check_ref(const char *name, unsigned int flags)
  18{
  19        if (!flags)
  20                return 1;
  21
  22        if (!skip_prefix(name, "refs/", &name))
  23                return 0;
  24
  25        /* REF_NORMAL means that we don't want the magic fake tag refs */
  26        if ((flags & REF_NORMAL) && check_refname_format(name, 0))
  27                return 0;
  28
  29        /* REF_HEADS means that we want regular branch heads */
  30        if ((flags & REF_HEADS) && starts_with(name, "heads/"))
  31                return 1;
  32
  33        /* REF_TAGS means that we want tags */
  34        if ((flags & REF_TAGS) && starts_with(name, "tags/"))
  35                return 1;
  36
  37        /* All type bits clear means that we are ok with anything */
  38        return !(flags & ~REF_NORMAL);
  39}
  40
  41int check_ref_type(const struct ref *ref, int flags)
  42{
  43        return check_ref(ref->name, flags);
  44}
  45
  46static void die_initial_contact(int got_at_least_one_head)
  47{
  48        if (got_at_least_one_head)
  49                die("The remote end hung up upon initial contact");
  50        else
  51                die("Could not read from remote repository.\n\n"
  52                    "Please make sure you have the correct access rights\n"
  53                    "and the repository exists.");
  54}
  55
  56static void parse_one_symref_info(struct string_list *symref, const char *val, int len)
  57{
  58        char *sym, *target;
  59        struct string_list_item *item;
  60
  61        if (!len)
  62                return; /* just "symref" */
  63        /* e.g. "symref=HEAD:refs/heads/master" */
  64        sym = xmemdupz(val, len);
  65        target = strchr(sym, ':');
  66        if (!target)
  67                /* just "symref=something" */
  68                goto reject;
  69        *(target++) = '\0';
  70        if (check_refname_format(sym, REFNAME_ALLOW_ONELEVEL) ||
  71            check_refname_format(target, REFNAME_ALLOW_ONELEVEL))
  72                /* "symref=bogus:pair */
  73                goto reject;
  74        item = string_list_append(symref, sym);
  75        item->util = target;
  76        return;
  77reject:
  78        free(sym);
  79        return;
  80}
  81
  82static void annotate_refs_with_symref_info(struct ref *ref)
  83{
  84        struct string_list symref = STRING_LIST_INIT_DUP;
  85        const char *feature_list = server_capabilities;
  86
  87        while (feature_list) {
  88                int len;
  89                const char *val;
  90
  91                val = parse_feature_value(feature_list, "symref", &len);
  92                if (!val)
  93                        break;
  94                parse_one_symref_info(&symref, val, len);
  95                feature_list = val + 1;
  96        }
  97        string_list_sort(&symref);
  98
  99        for (; ref; ref = ref->next) {
 100                struct string_list_item *item;
 101                item = string_list_lookup(&symref, ref->name);
 102                if (!item)
 103                        continue;
 104                ref->symref = xstrdup((char *)item->util);
 105        }
 106        string_list_clear(&symref, 0);
 107}
 108
 109/*
 110 * Read all the refs from the other end
 111 */
 112struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
 113                              struct ref **list, unsigned int flags,
 114                              struct sha1_array *extra_have,
 115                              struct sha1_array *shallow_points)
 116{
 117        struct ref **orig_list = list;
 118        int got_at_least_one_head = 0;
 119
 120        *list = NULL;
 121        for (;;) {
 122                struct ref *ref;
 123                struct object_id old_oid;
 124                char *name;
 125                int len, name_len;
 126                char *buffer = packet_buffer;
 127                const char *arg;
 128
 129                len = packet_read(in, &src_buf, &src_len,
 130                                  packet_buffer, sizeof(packet_buffer),
 131                                  PACKET_READ_GENTLE_ON_EOF |
 132                                  PACKET_READ_CHOMP_NEWLINE);
 133                if (len < 0)
 134                        die_initial_contact(got_at_least_one_head);
 135
 136                if (!len)
 137                        break;
 138
 139                if (len > 4 && skip_prefix(buffer, "ERR ", &arg))
 140                        die("remote error: %s", arg);
 141
 142                if (len == GIT_SHA1_HEXSZ + strlen("shallow ") &&
 143                        skip_prefix(buffer, "shallow ", &arg)) {
 144                        if (get_oid_hex(arg, &old_oid))
 145                                die("protocol error: expected shallow sha-1, got '%s'", arg);
 146                        if (!shallow_points)
 147                                die("repository on the other end cannot be shallow");
 148                        sha1_array_append(shallow_points, old_oid.hash);
 149                        continue;
 150                }
 151
 152                if (len < GIT_SHA1_HEXSZ + 2 || get_oid_hex(buffer, &old_oid) ||
 153                        buffer[GIT_SHA1_HEXSZ] != ' ')
 154                        die("protocol error: expected sha/ref, got '%s'", buffer);
 155                name = buffer + GIT_SHA1_HEXSZ + 1;
 156
 157                name_len = strlen(name);
 158                if (len != name_len + GIT_SHA1_HEXSZ + 1) {
 159                        free(server_capabilities);
 160                        server_capabilities = xstrdup(name + name_len + 1);
 161                }
 162
 163                if (extra_have && !strcmp(name, ".have")) {
 164                        sha1_array_append(extra_have, old_oid.hash);
 165                        continue;
 166                }
 167
 168                if (!check_ref(name, flags))
 169                        continue;
 170                ref = alloc_ref(buffer + GIT_SHA1_HEXSZ + 1);
 171                oidcpy(&ref->old_oid, &old_oid);
 172                *list = ref;
 173                list = &ref->next;
 174                got_at_least_one_head = 1;
 175        }
 176
 177        annotate_refs_with_symref_info(*orig_list);
 178
 179        return list;
 180}
 181
 182static const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
 183{
 184        int len;
 185
 186        if (!feature_list)
 187                return NULL;
 188
 189        len = strlen(feature);
 190        while (*feature_list) {
 191                const char *found = strstr(feature_list, feature);
 192                if (!found)
 193                        return NULL;
 194                if (feature_list == found || isspace(found[-1])) {
 195                        const char *value = found + len;
 196                        /* feature with no value (e.g., "thin-pack") */
 197                        if (!*value || isspace(*value)) {
 198                                if (lenp)
 199                                        *lenp = 0;
 200                                return value;
 201                        }
 202                        /* feature with a value (e.g., "agent=git/1.2.3") */
 203                        else if (*value == '=') {
 204                                value++;
 205                                if (lenp)
 206                                        *lenp = strcspn(value, " \t\n");
 207                                return value;
 208                        }
 209                        /*
 210                         * otherwise we matched a substring of another feature;
 211                         * keep looking
 212                         */
 213                }
 214                feature_list = found + 1;
 215        }
 216        return NULL;
 217}
 218
 219int parse_feature_request(const char *feature_list, const char *feature)
 220{
 221        return !!parse_feature_value(feature_list, feature, NULL);
 222}
 223
 224const char *server_feature_value(const char *feature, int *len)
 225{
 226        return parse_feature_value(server_capabilities, feature, len);
 227}
 228
 229int server_supports(const char *feature)
 230{
 231        return !!server_feature_value(feature, NULL);
 232}
 233
 234enum protocol {
 235        PROTO_LOCAL = 1,
 236        PROTO_FILE,
 237        PROTO_SSH,
 238        PROTO_GIT
 239};
 240
 241int url_is_local_not_ssh(const char *url)
 242{
 243        const char *colon = strchr(url, ':');
 244        const char *slash = strchr(url, '/');
 245        return !colon || (slash && slash < colon) ||
 246                has_dos_drive_prefix(url);
 247}
 248
 249static const char *prot_name(enum protocol protocol)
 250{
 251        switch (protocol) {
 252                case PROTO_LOCAL:
 253                case PROTO_FILE:
 254                        return "file";
 255                case PROTO_SSH:
 256                        return "ssh";
 257                case PROTO_GIT:
 258                        return "git";
 259                default:
 260                        return "unknown protocol";
 261        }
 262}
 263
 264static enum protocol get_protocol(const char *name)
 265{
 266        if (!strcmp(name, "ssh"))
 267                return PROTO_SSH;
 268        if (!strcmp(name, "git"))
 269                return PROTO_GIT;
 270        if (!strcmp(name, "git+ssh"))
 271                return PROTO_SSH;
 272        if (!strcmp(name, "ssh+git"))
 273                return PROTO_SSH;
 274        if (!strcmp(name, "file"))
 275                return PROTO_FILE;
 276        die("I don't handle protocol '%s'", name);
 277}
 278
 279static char *host_end(char **hoststart, int removebrackets)
 280{
 281        char *host = *hoststart;
 282        char *end;
 283        char *start = strstr(host, "@[");
 284        if (start)
 285                start++; /* Jump over '@' */
 286        else
 287                start = host;
 288        if (start[0] == '[') {
 289                end = strchr(start + 1, ']');
 290                if (end) {
 291                        if (removebrackets) {
 292                                *end = 0;
 293                                memmove(start, start + 1, end - start);
 294                                end++;
 295                        }
 296                } else
 297                        end = host;
 298        } else
 299                end = host;
 300        return end;
 301}
 302
 303#define STR_(s) # s
 304#define STR(s)  STR_(s)
 305
 306static void get_host_and_port(char **host, const char **port)
 307{
 308        char *colon, *end;
 309        end = host_end(host, 1);
 310        colon = strchr(end, ':');
 311        if (colon) {
 312                long portnr = strtol(colon + 1, &end, 10);
 313                if (end != colon + 1 && *end == '\0' && 0 <= portnr && portnr < 65536) {
 314                        *colon = 0;
 315                        *port = colon + 1;
 316                } else if (!colon[1]) {
 317                        *colon = 0;
 318                }
 319        }
 320}
 321
 322static void enable_keepalive(int sockfd)
 323{
 324        int ka = 1;
 325
 326        if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
 327                fprintf(stderr, "unable to set SO_KEEPALIVE on socket: %s\n",
 328                        strerror(errno));
 329}
 330
 331#ifndef NO_IPV6
 332
 333static const char *ai_name(const struct addrinfo *ai)
 334{
 335        static char addr[NI_MAXHOST];
 336        if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
 337                        NI_NUMERICHOST) != 0)
 338                xsnprintf(addr, sizeof(addr), "(unknown)");
 339
 340        return addr;
 341}
 342
 343/*
 344 * Returns a connected socket() fd, or else die()s.
 345 */
 346static int git_tcp_connect_sock(char *host, int flags)
 347{
 348        struct strbuf error_message = STRBUF_INIT;
 349        int sockfd = -1;
 350        const char *port = STR(DEFAULT_GIT_PORT);
 351        struct addrinfo hints, *ai0, *ai;
 352        int gai;
 353        int cnt = 0;
 354
 355        get_host_and_port(&host, &port);
 356        if (!*port)
 357                port = "<none>";
 358
 359        memset(&hints, 0, sizeof(hints));
 360        hints.ai_socktype = SOCK_STREAM;
 361        hints.ai_protocol = IPPROTO_TCP;
 362
 363        if (flags & CONNECT_VERBOSE)
 364                fprintf(stderr, "Looking up %s ... ", host);
 365
 366        gai = getaddrinfo(host, port, &hints, &ai);
 367        if (gai)
 368                die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
 369
 370        if (flags & CONNECT_VERBOSE)
 371                fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 372
 373        for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
 374                sockfd = socket(ai->ai_family,
 375                                ai->ai_socktype, ai->ai_protocol);
 376                if ((sockfd < 0) ||
 377                    (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
 378                        strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 379                                    host, cnt, ai_name(ai), strerror(errno));
 380                        if (0 <= sockfd)
 381                                close(sockfd);
 382                        sockfd = -1;
 383                        continue;
 384                }
 385                if (flags & CONNECT_VERBOSE)
 386                        fprintf(stderr, "%s ", ai_name(ai));
 387                break;
 388        }
 389
 390        freeaddrinfo(ai0);
 391
 392        if (sockfd < 0)
 393                die("unable to connect to %s:\n%s", host, error_message.buf);
 394
 395        enable_keepalive(sockfd);
 396
 397        if (flags & CONNECT_VERBOSE)
 398                fprintf(stderr, "done.\n");
 399
 400        strbuf_release(&error_message);
 401
 402        return sockfd;
 403}
 404
 405#else /* NO_IPV6 */
 406
 407/*
 408 * Returns a connected socket() fd, or else die()s.
 409 */
 410static int git_tcp_connect_sock(char *host, int flags)
 411{
 412        struct strbuf error_message = STRBUF_INIT;
 413        int sockfd = -1;
 414        const char *port = STR(DEFAULT_GIT_PORT);
 415        char *ep;
 416        struct hostent *he;
 417        struct sockaddr_in sa;
 418        char **ap;
 419        unsigned int nport;
 420        int cnt;
 421
 422        get_host_and_port(&host, &port);
 423
 424        if (flags & CONNECT_VERBOSE)
 425                fprintf(stderr, "Looking up %s ... ", host);
 426
 427        he = gethostbyname(host);
 428        if (!he)
 429                die("Unable to look up %s (%s)", host, hstrerror(h_errno));
 430        nport = strtoul(port, &ep, 10);
 431        if ( ep == port || *ep ) {
 432                /* Not numeric */
 433                struct servent *se = getservbyname(port,"tcp");
 434                if ( !se )
 435                        die("Unknown port %s", port);
 436                nport = se->s_port;
 437        }
 438
 439        if (flags & CONNECT_VERBOSE)
 440                fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 441
 442        for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
 443                memset(&sa, 0, sizeof sa);
 444                sa.sin_family = he->h_addrtype;
 445                sa.sin_port = htons(nport);
 446                memcpy(&sa.sin_addr, *ap, he->h_length);
 447
 448                sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 449                if ((sockfd < 0) ||
 450                    connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 451                        strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 452                                host,
 453                                cnt,
 454                                inet_ntoa(*(struct in_addr *)&sa.sin_addr),
 455                                strerror(errno));
 456                        if (0 <= sockfd)
 457                                close(sockfd);
 458                        sockfd = -1;
 459                        continue;
 460                }
 461                if (flags & CONNECT_VERBOSE)
 462                        fprintf(stderr, "%s ",
 463                                inet_ntoa(*(struct in_addr *)&sa.sin_addr));
 464                break;
 465        }
 466
 467        if (sockfd < 0)
 468                die("unable to connect to %s:\n%s", host, error_message.buf);
 469
 470        enable_keepalive(sockfd);
 471
 472        if (flags & CONNECT_VERBOSE)
 473                fprintf(stderr, "done.\n");
 474
 475        return sockfd;
 476}
 477
 478#endif /* NO_IPV6 */
 479
 480
 481static void git_tcp_connect(int fd[2], char *host, int flags)
 482{
 483        int sockfd = git_tcp_connect_sock(host, flags);
 484
 485        fd[0] = sockfd;
 486        fd[1] = dup(sockfd);
 487}
 488
 489
 490static char *git_proxy_command;
 491
 492static int git_proxy_command_options(const char *var, const char *value,
 493                void *cb)
 494{
 495        if (!strcmp(var, "core.gitproxy")) {
 496                const char *for_pos;
 497                int matchlen = -1;
 498                int hostlen;
 499                const char *rhost_name = cb;
 500                int rhost_len = strlen(rhost_name);
 501
 502                if (git_proxy_command)
 503                        return 0;
 504                if (!value)
 505                        return config_error_nonbool(var);
 506                /* [core]
 507                 * ;# matches www.kernel.org as well
 508                 * gitproxy = netcatter-1 for kernel.org
 509                 * gitproxy = netcatter-2 for sample.xz
 510                 * gitproxy = netcatter-default
 511                 */
 512                for_pos = strstr(value, " for ");
 513                if (!for_pos)
 514                        /* matches everybody */
 515                        matchlen = strlen(value);
 516                else {
 517                        hostlen = strlen(for_pos + 5);
 518                        if (rhost_len < hostlen)
 519                                matchlen = -1;
 520                        else if (!strncmp(for_pos + 5,
 521                                          rhost_name + rhost_len - hostlen,
 522                                          hostlen) &&
 523                                 ((rhost_len == hostlen) ||
 524                                  rhost_name[rhost_len - hostlen -1] == '.'))
 525                                matchlen = for_pos - value;
 526                        else
 527                                matchlen = -1;
 528                }
 529                if (0 <= matchlen) {
 530                        /* core.gitproxy = none for kernel.org */
 531                        if (matchlen == 4 &&
 532                            !memcmp(value, "none", 4))
 533                                matchlen = 0;
 534                        git_proxy_command = xmemdupz(value, matchlen);
 535                }
 536                return 0;
 537        }
 538
 539        return git_default_config(var, value, cb);
 540}
 541
 542static int git_use_proxy(const char *host)
 543{
 544        git_proxy_command = getenv("GIT_PROXY_COMMAND");
 545        git_config(git_proxy_command_options, (void*)host);
 546        return (git_proxy_command && *git_proxy_command);
 547}
 548
 549static struct child_process *git_proxy_connect(int fd[2], char *host)
 550{
 551        const char *port = STR(DEFAULT_GIT_PORT);
 552        struct child_process *proxy;
 553
 554        get_host_and_port(&host, &port);
 555
 556        proxy = xmalloc(sizeof(*proxy));
 557        child_process_init(proxy);
 558        argv_array_push(&proxy->args, git_proxy_command);
 559        argv_array_push(&proxy->args, host);
 560        argv_array_push(&proxy->args, port);
 561        proxy->in = -1;
 562        proxy->out = -1;
 563        if (start_command(proxy))
 564                die("cannot start proxy %s", git_proxy_command);
 565        fd[0] = proxy->out; /* read from proxy stdout */
 566        fd[1] = proxy->in;  /* write to proxy stdin */
 567        return proxy;
 568}
 569
 570static char *get_port(char *host)
 571{
 572        char *end;
 573        char *p = strchr(host, ':');
 574
 575        if (p) {
 576                long port = strtol(p + 1, &end, 10);
 577                if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
 578                        *p = '\0';
 579                        return p+1;
 580                }
 581        }
 582
 583        return NULL;
 584}
 585
 586/*
 587 * Extract protocol and relevant parts from the specified connection URL.
 588 * The caller must free() the returned strings.
 589 */
 590static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
 591                                       char **ret_path)
 592{
 593        char *url;
 594        char *host, *path;
 595        char *end;
 596        int separator = '/';
 597        enum protocol protocol = PROTO_LOCAL;
 598
 599        if (is_url(url_orig))
 600                url = url_decode(url_orig);
 601        else
 602                url = xstrdup(url_orig);
 603
 604        host = strstr(url, "://");
 605        if (host) {
 606                *host = '\0';
 607                protocol = get_protocol(url);
 608                host += 3;
 609        } else {
 610                host = url;
 611                if (!url_is_local_not_ssh(url)) {
 612                        protocol = PROTO_SSH;
 613                        separator = ':';
 614                }
 615        }
 616
 617        /*
 618         * Don't do destructive transforms as protocol code does
 619         * '[]' unwrapping in get_host_and_port()
 620         */
 621        end = host_end(&host, 0);
 622
 623        if (protocol == PROTO_LOCAL)
 624                path = end;
 625        else if (protocol == PROTO_FILE && has_dos_drive_prefix(end))
 626                path = end; /* "file://$(pwd)" may be "file://C:/projects/repo" */
 627        else
 628                path = strchr(end, separator);
 629
 630        if (!path || !*path)
 631                die("No path specified. See 'man git-pull' for valid url syntax");
 632
 633        /*
 634         * null-terminate hostname and point path to ~ for URL's like this:
 635         *    ssh://host.xz/~user/repo
 636         */
 637
 638        end = path; /* Need to \0 terminate host here */
 639        if (separator == ':')
 640                path++; /* path starts after ':' */
 641        if (protocol == PROTO_GIT || protocol == PROTO_SSH) {
 642                if (path[1] == '~')
 643                        path++;
 644        }
 645
 646        path = xstrdup(path);
 647        *end = '\0';
 648
 649        *ret_host = xstrdup(host);
 650        *ret_path = path;
 651        free(url);
 652        return protocol;
 653}
 654
 655static struct child_process no_fork = CHILD_PROCESS_INIT;
 656
 657/*
 658 * This returns a dummy child_process if the transport protocol does not
 659 * need fork(2), or a struct child_process object if it does.  Once done,
 660 * finish the connection with finish_connect() with the value returned from
 661 * this function (it is safe to call finish_connect() with NULL to support
 662 * the former case).
 663 *
 664 * If it returns, the connect is successful; it just dies on errors (this
 665 * will hopefully be changed in a libification effort, to return NULL when
 666 * the connection failed).
 667 */
 668struct child_process *git_connect(int fd[2], const char *url,
 669                                  const char *prog, int flags)
 670{
 671        char *hostandport, *path;
 672        struct child_process *conn = &no_fork;
 673        enum protocol protocol;
 674        struct strbuf cmd = STRBUF_INIT;
 675
 676        /* Without this we cannot rely on waitpid() to tell
 677         * what happened to our children.
 678         */
 679        signal(SIGCHLD, SIG_DFL);
 680
 681        protocol = parse_connect_url(url, &hostandport, &path);
 682        if ((flags & CONNECT_DIAG_URL) && (protocol != PROTO_SSH)) {
 683                printf("Diag: url=%s\n", url ? url : "NULL");
 684                printf("Diag: protocol=%s\n", prot_name(protocol));
 685                printf("Diag: hostandport=%s\n", hostandport ? hostandport : "NULL");
 686                printf("Diag: path=%s\n", path ? path : "NULL");
 687                conn = NULL;
 688        } else if (protocol == PROTO_GIT) {
 689                /*
 690                 * Set up virtual host information based on where we will
 691                 * connect, unless the user has overridden us in
 692                 * the environment.
 693                 */
 694                char *target_host = getenv("GIT_OVERRIDE_VIRTUAL_HOST");
 695                if (target_host)
 696                        target_host = xstrdup(target_host);
 697                else
 698                        target_host = xstrdup(hostandport);
 699
 700                transport_check_allowed("git");
 701
 702                /* These underlying connection commands die() if they
 703                 * cannot connect.
 704                 */
 705                if (git_use_proxy(hostandport))
 706                        conn = git_proxy_connect(fd, hostandport);
 707                else
 708                        git_tcp_connect(fd, hostandport, flags);
 709                /*
 710                 * Separate original protocol components prog and path
 711                 * from extended host header with a NUL byte.
 712                 *
 713                 * Note: Do not add any other headers here!  Doing so
 714                 * will cause older git-daemon servers to crash.
 715                 */
 716                packet_write(fd[1],
 717                             "%s %s%chost=%s%c",
 718                             prog, path, 0,
 719                             target_host, 0);
 720                free(target_host);
 721        } else {
 722                conn = xmalloc(sizeof(*conn));
 723                child_process_init(conn);
 724
 725                strbuf_addstr(&cmd, prog);
 726                strbuf_addch(&cmd, ' ');
 727                sq_quote_buf(&cmd, path);
 728
 729                /* remove repo-local variables from the environment */
 730                conn->env = local_repo_env;
 731                conn->use_shell = 1;
 732                conn->in = conn->out = -1;
 733                if (protocol == PROTO_SSH) {
 734                        const char *ssh;
 735                        int putty = 0, tortoiseplink = 0;
 736                        char *ssh_host = hostandport;
 737                        const char *port = NULL;
 738                        transport_check_allowed("ssh");
 739                        get_host_and_port(&ssh_host, &port);
 740
 741                        if (!port)
 742                                port = get_port(ssh_host);
 743
 744                        if (flags & CONNECT_DIAG_URL) {
 745                                printf("Diag: url=%s\n", url ? url : "NULL");
 746                                printf("Diag: protocol=%s\n", prot_name(protocol));
 747                                printf("Diag: userandhost=%s\n", ssh_host ? ssh_host : "NULL");
 748                                printf("Diag: port=%s\n", port ? port : "NONE");
 749                                printf("Diag: path=%s\n", path ? path : "NULL");
 750
 751                                free(hostandport);
 752                                free(path);
 753                                free(conn);
 754                                return NULL;
 755                        }
 756
 757                        ssh = getenv("GIT_SSH_COMMAND");
 758                        if (!ssh) {
 759                                const char *base;
 760                                char *ssh_dup;
 761
 762                                /*
 763                                 * GIT_SSH is the no-shell version of
 764                                 * GIT_SSH_COMMAND (and must remain so for
 765                                 * historical compatibility).
 766                                 */
 767                                conn->use_shell = 0;
 768
 769                                ssh = getenv("GIT_SSH");
 770                                if (!ssh)
 771                                        ssh = "ssh";
 772
 773                                ssh_dup = xstrdup(ssh);
 774                                base = basename(ssh_dup);
 775
 776                                tortoiseplink = !strcasecmp(base, "tortoiseplink") ||
 777                                        !strcasecmp(base, "tortoiseplink.exe");
 778                                putty = tortoiseplink ||
 779                                        !strcasecmp(base, "plink") ||
 780                                        !strcasecmp(base, "plink.exe");
 781
 782                                free(ssh_dup);
 783                        }
 784
 785                        argv_array_push(&conn->args, ssh);
 786                        if (tortoiseplink)
 787                                argv_array_push(&conn->args, "-batch");
 788                        if (port) {
 789                                /* P is for PuTTY, p is for OpenSSH */
 790                                argv_array_push(&conn->args, putty ? "-P" : "-p");
 791                                argv_array_push(&conn->args, port);
 792                        }
 793                        argv_array_push(&conn->args, ssh_host);
 794                } else {
 795                        transport_check_allowed("file");
 796                }
 797                argv_array_push(&conn->args, cmd.buf);
 798
 799                if (start_command(conn))
 800                        die("unable to fork");
 801
 802                fd[0] = conn->out; /* read from child's stdout */
 803                fd[1] = conn->in;  /* write to child's stdin */
 804                strbuf_release(&cmd);
 805        }
 806        free(hostandport);
 807        free(path);
 808        return conn;
 809}
 810
 811int git_connection_is_socket(struct child_process *conn)
 812{
 813        return conn == &no_fork;
 814}
 815
 816int finish_connect(struct child_process *conn)
 817{
 818        int code;
 819        if (!conn || git_connection_is_socket(conn))
 820                return 0;
 821
 822        code = finish_command(conn);
 823        free(conn);
 824        return code;
 825}