Andrew's git / gitweb.git / connect.c
?
connect.con commit Merge branch 'jk/diagnose-config-mmap-failure' into maint (c5baf18)
   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
  13static char *server_capabilities;
  14static const char *parse_feature_value(const char *, const char *, int *);
  15
  16static int check_ref(const char *name, unsigned int flags)
  17{
  18        if (!flags)
  19                return 1;
  20
  21        if (!skip_prefix(name, "refs/", &name))
  22                return 0;
  23
  24        /* REF_NORMAL means that we don't want the magic fake tag refs */
  25        if ((flags & REF_NORMAL) && check_refname_format(name, 0))
  26                return 0;
  27
  28        /* REF_HEADS means that we want regular branch heads */
  29        if ((flags & REF_HEADS) && starts_with(name, "heads/"))
  30                return 1;
  31
  32        /* REF_TAGS means that we want tags */
  33        if ((flags & REF_TAGS) && starts_with(name, "tags/"))
  34                return 1;
  35
  36        /* All type bits clear means that we are ok with anything */
  37        return !(flags & ~REF_NORMAL);
  38}
  39
  40int check_ref_type(const struct ref *ref, int flags)
  41{
  42        return check_ref(ref->name, flags);
  43}
  44
  45static void die_initial_contact(int got_at_least_one_head)
  46{
  47        if (got_at_least_one_head)
  48                die("The remote end hung up upon initial contact");
  49        else
  50                die("Could not read from remote repository.\n\n"
  51                    "Please make sure you have the correct access rights\n"
  52                    "and the repository exists.");
  53}
  54
  55static void parse_one_symref_info(struct string_list *symref, const char *val, int len)
  56{
  57        char *sym, *target;
  58        struct string_list_item *item;
  59
  60        if (!len)
  61                return; /* just "symref" */
  62        /* e.g. "symref=HEAD:refs/heads/master" */
  63        sym = xmemdupz(val, len);
  64        target = strchr(sym, ':');
  65        if (!target)
  66                /* just "symref=something" */
  67                goto reject;
  68        *(target++) = '\0';
  69        if (check_refname_format(sym, REFNAME_ALLOW_ONELEVEL) ||
  70            check_refname_format(target, REFNAME_ALLOW_ONELEVEL))
  71                /* "symref=bogus:pair */
  72                goto reject;
  73        item = string_list_append(symref, sym);
  74        item->util = target;
  75        return;
  76reject:
  77        free(sym);
  78        return;
  79}
  80
  81static void annotate_refs_with_symref_info(struct ref *ref)
  82{
  83        struct string_list symref = STRING_LIST_INIT_DUP;
  84        const char *feature_list = server_capabilities;
  85
  86        while (feature_list) {
  87                int len;
  88                const char *val;
  89
  90                val = parse_feature_value(feature_list, "symref", &len);
  91                if (!val)
  92                        break;
  93                parse_one_symref_info(&symref, val, len);
  94                feature_list = val + 1;
  95        }
  96        string_list_sort(&symref);
  97
  98        for (; ref; ref = ref->next) {
  99                struct string_list_item *item;
 100                item = string_list_lookup(&symref, ref->name);
 101                if (!item)
 102                        continue;
 103                ref->symref = xstrdup((char *)item->util);
 104        }
 105        string_list_clear(&symref, 0);
 106}
 107
 108/*
 109 * Read all the refs from the other end
 110 */
 111struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
 112                              struct ref **list, unsigned int flags,
 113                              struct sha1_array *extra_have,
 114                              struct sha1_array *shallow_points)
 115{
 116        struct ref **orig_list = list;
 117        int got_at_least_one_head = 0;
 118
 119        *list = NULL;
 120        for (;;) {
 121                struct ref *ref;
 122                unsigned char old_sha1[20];
 123                char *name;
 124                int len, name_len;
 125                char *buffer = packet_buffer;
 126                const char *arg;
 127
 128                len = packet_read(in, &src_buf, &src_len,
 129                                  packet_buffer, sizeof(packet_buffer),
 130                                  PACKET_READ_GENTLE_ON_EOF |
 131                                  PACKET_READ_CHOMP_NEWLINE);
 132                if (len < 0)
 133                        die_initial_contact(got_at_least_one_head);
 134
 135                if (!len)
 136                        break;
 137
 138                if (len > 4 && skip_prefix(buffer, "ERR ", &arg))
 139                        die("remote error: %s", arg);
 140
 141                if (len == 48 && skip_prefix(buffer, "shallow ", &arg)) {
 142                        if (get_sha1_hex(arg, old_sha1))
 143                                die("protocol error: expected shallow sha-1, got '%s'", arg);
 144                        if (!shallow_points)
 145                                die("repository on the other end cannot be shallow");
 146                        sha1_array_append(shallow_points, old_sha1);
 147                        continue;
 148                }
 149
 150                if (len < 42 || get_sha1_hex(buffer, old_sha1) || buffer[40] != ' ')
 151                        die("protocol error: expected sha/ref, got '%s'", buffer);
 152                name = buffer + 41;
 153
 154                name_len = strlen(name);
 155                if (len != name_len + 41) {
 156                        free(server_capabilities);
 157                        server_capabilities = xstrdup(name + name_len + 1);
 158                }
 159
 160                if (extra_have && !strcmp(name, ".have")) {
 161                        sha1_array_append(extra_have, old_sha1);
 162                        continue;
 163                }
 164
 165                if (!check_ref(name, flags))
 166                        continue;
 167                ref = alloc_ref(buffer + 41);
 168                hashcpy(ref->old_sha1, old_sha1);
 169                *list = ref;
 170                list = &ref->next;
 171                got_at_least_one_head = 1;
 172        }
 173
 174        annotate_refs_with_symref_info(*orig_list);
 175
 176        return list;
 177}
 178
 179static const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
 180{
 181        int len;
 182
 183        if (!feature_list)
 184                return NULL;
 185
 186        len = strlen(feature);
 187        while (*feature_list) {
 188                const char *found = strstr(feature_list, feature);
 189                if (!found)
 190                        return NULL;
 191                if (feature_list == found || isspace(found[-1])) {
 192                        const char *value = found + len;
 193                        /* feature with no value (e.g., "thin-pack") */
 194                        if (!*value || isspace(*value)) {
 195                                if (lenp)
 196                                        *lenp = 0;
 197                                return value;
 198                        }
 199                        /* feature with a value (e.g., "agent=git/1.2.3") */
 200                        else if (*value == '=') {
 201                                value++;
 202                                if (lenp)
 203                                        *lenp = strcspn(value, " \t\n");
 204                                return value;
 205                        }
 206                        /*
 207                         * otherwise we matched a substring of another feature;
 208                         * keep looking
 209                         */
 210                }
 211                feature_list = found + 1;
 212        }
 213        return NULL;
 214}
 215
 216int parse_feature_request(const char *feature_list, const char *feature)
 217{
 218        return !!parse_feature_value(feature_list, feature, NULL);
 219}
 220
 221const char *server_feature_value(const char *feature, int *len)
 222{
 223        return parse_feature_value(server_capabilities, feature, len);
 224}
 225
 226int server_supports(const char *feature)
 227{
 228        return !!server_feature_value(feature, NULL);
 229}
 230
 231enum protocol {
 232        PROTO_LOCAL = 1,
 233        PROTO_FILE,
 234        PROTO_SSH,
 235        PROTO_GIT
 236};
 237
 238int url_is_local_not_ssh(const char *url)
 239{
 240        const char *colon = strchr(url, ':');
 241        const char *slash = strchr(url, '/');
 242        return !colon || (slash && slash < colon) ||
 243                has_dos_drive_prefix(url);
 244}
 245
 246static const char *prot_name(enum protocol protocol)
 247{
 248        switch (protocol) {
 249                case PROTO_LOCAL:
 250                case PROTO_FILE:
 251                        return "file";
 252                case PROTO_SSH:
 253                        return "ssh";
 254                case PROTO_GIT:
 255                        return "git";
 256                default:
 257                        return "unkown protocol";
 258        }
 259}
 260
 261static enum protocol get_protocol(const char *name)
 262{
 263        if (!strcmp(name, "ssh"))
 264                return PROTO_SSH;
 265        if (!strcmp(name, "git"))
 266                return PROTO_GIT;
 267        if (!strcmp(name, "git+ssh"))
 268                return PROTO_SSH;
 269        if (!strcmp(name, "ssh+git"))
 270                return PROTO_SSH;
 271        if (!strcmp(name, "file"))
 272                return PROTO_FILE;
 273        die("I don't handle protocol '%s'", name);
 274}
 275
 276static char *host_end(char **hoststart, int removebrackets)
 277{
 278        char *host = *hoststart;
 279        char *end;
 280        char *start = strstr(host, "@[");
 281        if (start)
 282                start++; /* Jump over '@' */
 283        else
 284                start = host;
 285        if (start[0] == '[') {
 286                end = strchr(start + 1, ']');
 287                if (end) {
 288                        if (removebrackets) {
 289                                *end = 0;
 290                                memmove(start, start + 1, end - start);
 291                                end++;
 292                        }
 293                } else
 294                        end = host;
 295        } else
 296                end = host;
 297        return end;
 298}
 299
 300#define STR_(s) # s
 301#define STR(s)  STR_(s)
 302
 303static void get_host_and_port(char **host, const char **port)
 304{
 305        char *colon, *end;
 306        end = host_end(host, 1);
 307        colon = strchr(end, ':');
 308        if (colon) {
 309                long portnr = strtol(colon + 1, &end, 10);
 310                if (end != colon + 1 && *end == '\0' && 0 <= portnr && portnr < 65536) {
 311                        *colon = 0;
 312                        *port = colon + 1;
 313                } else if (!colon[1]) {
 314                        *colon = 0;
 315                }
 316        }
 317}
 318
 319static void enable_keepalive(int sockfd)
 320{
 321        int ka = 1;
 322
 323        if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
 324                fprintf(stderr, "unable to set SO_KEEPALIVE on socket: %s\n",
 325                        strerror(errno));
 326}
 327
 328#ifndef NO_IPV6
 329
 330static const char *ai_name(const struct addrinfo *ai)
 331{
 332        static char addr[NI_MAXHOST];
 333        if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
 334                        NI_NUMERICHOST) != 0)
 335                strcpy(addr, "(unknown)");
 336
 337        return addr;
 338}
 339
 340/*
 341 * Returns a connected socket() fd, or else die()s.
 342 */
 343static int git_tcp_connect_sock(char *host, int flags)
 344{
 345        struct strbuf error_message = STRBUF_INIT;
 346        int sockfd = -1;
 347        const char *port = STR(DEFAULT_GIT_PORT);
 348        struct addrinfo hints, *ai0, *ai;
 349        int gai;
 350        int cnt = 0;
 351
 352        get_host_and_port(&host, &port);
 353        if (!*port)
 354                port = "<none>";
 355
 356        memset(&hints, 0, sizeof(hints));
 357        hints.ai_socktype = SOCK_STREAM;
 358        hints.ai_protocol = IPPROTO_TCP;
 359
 360        if (flags & CONNECT_VERBOSE)
 361                fprintf(stderr, "Looking up %s ... ", host);
 362
 363        gai = getaddrinfo(host, port, &hints, &ai);
 364        if (gai)
 365                die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
 366
 367        if (flags & CONNECT_VERBOSE)
 368                fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 369
 370        for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
 371                sockfd = socket(ai->ai_family,
 372                                ai->ai_socktype, ai->ai_protocol);
 373                if ((sockfd < 0) ||
 374                    (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
 375                        strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 376                                    host, cnt, ai_name(ai), strerror(errno));
 377                        if (0 <= sockfd)
 378                                close(sockfd);
 379                        sockfd = -1;
 380                        continue;
 381                }
 382                if (flags & CONNECT_VERBOSE)
 383                        fprintf(stderr, "%s ", ai_name(ai));
 384                break;
 385        }
 386
 387        freeaddrinfo(ai0);
 388
 389        if (sockfd < 0)
 390                die("unable to connect to %s:\n%s", host, error_message.buf);
 391
 392        enable_keepalive(sockfd);
 393
 394        if (flags & CONNECT_VERBOSE)
 395                fprintf(stderr, "done.\n");
 396
 397        strbuf_release(&error_message);
 398
 399        return sockfd;
 400}
 401
 402#else /* NO_IPV6 */
 403
 404/*
 405 * Returns a connected socket() fd, or else die()s.
 406 */
 407static int git_tcp_connect_sock(char *host, int flags)
 408{
 409        struct strbuf error_message = STRBUF_INIT;
 410        int sockfd = -1;
 411        const char *port = STR(DEFAULT_GIT_PORT);
 412        char *ep;
 413        struct hostent *he;
 414        struct sockaddr_in sa;
 415        char **ap;
 416        unsigned int nport;
 417        int cnt;
 418
 419        get_host_and_port(&host, &port);
 420
 421        if (flags & CONNECT_VERBOSE)
 422                fprintf(stderr, "Looking up %s ... ", host);
 423
 424        he = gethostbyname(host);
 425        if (!he)
 426                die("Unable to look up %s (%s)", host, hstrerror(h_errno));
 427        nport = strtoul(port, &ep, 10);
 428        if ( ep == port || *ep ) {
 429                /* Not numeric */
 430                struct servent *se = getservbyname(port,"tcp");
 431                if ( !se )
 432                        die("Unknown port %s", port);
 433                nport = se->s_port;
 434        }
 435
 436        if (flags & CONNECT_VERBOSE)
 437                fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 438
 439        for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
 440                memset(&sa, 0, sizeof sa);
 441                sa.sin_family = he->h_addrtype;
 442                sa.sin_port = htons(nport);
 443                memcpy(&sa.sin_addr, *ap, he->h_length);
 444
 445                sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 446                if ((sockfd < 0) ||
 447                    connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 448                        strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 449                                host,
 450                                cnt,
 451                                inet_ntoa(*(struct in_addr *)&sa.sin_addr),
 452                                strerror(errno));
 453                        if (0 <= sockfd)
 454                                close(sockfd);
 455                        sockfd = -1;
 456                        continue;
 457                }
 458                if (flags & CONNECT_VERBOSE)
 459                        fprintf(stderr, "%s ",
 460                                inet_ntoa(*(struct in_addr *)&sa.sin_addr));
 461                break;
 462        }
 463
 464        if (sockfd < 0)
 465                die("unable to connect to %s:\n%s", host, error_message.buf);
 466
 467        enable_keepalive(sockfd);
 468
 469        if (flags & CONNECT_VERBOSE)
 470                fprintf(stderr, "done.\n");
 471
 472        return sockfd;
 473}
 474
 475#endif /* NO_IPV6 */
 476
 477
 478static void git_tcp_connect(int fd[2], char *host, int flags)
 479{
 480        int sockfd = git_tcp_connect_sock(host, flags);
 481
 482        fd[0] = sockfd;
 483        fd[1] = dup(sockfd);
 484}
 485
 486
 487static char *git_proxy_command;
 488
 489static int git_proxy_command_options(const char *var, const char *value,
 490                void *cb)
 491{
 492        if (!strcmp(var, "core.gitproxy")) {
 493                const char *for_pos;
 494                int matchlen = -1;
 495                int hostlen;
 496                const char *rhost_name = cb;
 497                int rhost_len = strlen(rhost_name);
 498
 499                if (git_proxy_command)
 500                        return 0;
 501                if (!value)
 502                        return config_error_nonbool(var);
 503                /* [core]
 504                 * ;# matches www.kernel.org as well
 505                 * gitproxy = netcatter-1 for kernel.org
 506                 * gitproxy = netcatter-2 for sample.xz
 507                 * gitproxy = netcatter-default
 508                 */
 509                for_pos = strstr(value, " for ");
 510                if (!for_pos)
 511                        /* matches everybody */
 512                        matchlen = strlen(value);
 513                else {
 514                        hostlen = strlen(for_pos + 5);
 515                        if (rhost_len < hostlen)
 516                                matchlen = -1;
 517                        else if (!strncmp(for_pos + 5,
 518                                          rhost_name + rhost_len - hostlen,
 519                                          hostlen) &&
 520                                 ((rhost_len == hostlen) ||
 521                                  rhost_name[rhost_len - hostlen -1] == '.'))
 522                                matchlen = for_pos - value;
 523                        else
 524                                matchlen = -1;
 525                }
 526                if (0 <= matchlen) {
 527                        /* core.gitproxy = none for kernel.org */
 528                        if (matchlen == 4 &&
 529                            !memcmp(value, "none", 4))
 530                                matchlen = 0;
 531                        git_proxy_command = xmemdupz(value, matchlen);
 532                }
 533                return 0;
 534        }
 535
 536        return git_default_config(var, value, cb);
 537}
 538
 539static int git_use_proxy(const char *host)
 540{
 541        git_proxy_command = getenv("GIT_PROXY_COMMAND");
 542        git_config(git_proxy_command_options, (void*)host);
 543        return (git_proxy_command && *git_proxy_command);
 544}
 545
 546static struct child_process *git_proxy_connect(int fd[2], char *host)
 547{
 548        const char *port = STR(DEFAULT_GIT_PORT);
 549        struct child_process *proxy;
 550
 551        get_host_and_port(&host, &port);
 552
 553        proxy = xmalloc(sizeof(*proxy));
 554        child_process_init(proxy);
 555        argv_array_push(&proxy->args, git_proxy_command);
 556        argv_array_push(&proxy->args, host);
 557        argv_array_push(&proxy->args, port);
 558        proxy->in = -1;
 559        proxy->out = -1;
 560        if (start_command(proxy))
 561                die("cannot start proxy %s", git_proxy_command);
 562        fd[0] = proxy->out; /* read from proxy stdout */
 563        fd[1] = proxy->in;  /* write to proxy stdin */
 564        return proxy;
 565}
 566
 567static char *get_port(char *host)
 568{
 569        char *end;
 570        char *p = strchr(host, ':');
 571
 572        if (p) {
 573                long port = strtol(p + 1, &end, 10);
 574                if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
 575                        *p = '\0';
 576                        return p+1;
 577                }
 578        }
 579
 580        return NULL;
 581}
 582
 583/*
 584 * Extract protocol and relevant parts from the specified connection URL.
 585 * The caller must free() the returned strings.
 586 */
 587static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
 588                                       char **ret_path)
 589{
 590        char *url;
 591        char *host, *path;
 592        char *end;
 593        int separator = '/';
 594        enum protocol protocol = PROTO_LOCAL;
 595
 596        if (is_url(url_orig))
 597                url = url_decode(url_orig);
 598        else
 599                url = xstrdup(url_orig);
 600
 601        host = strstr(url, "://");
 602        if (host) {
 603                *host = '\0';
 604                protocol = get_protocol(url);
 605                host += 3;
 606        } else {
 607                host = url;
 608                if (!url_is_local_not_ssh(url)) {
 609                        protocol = PROTO_SSH;
 610                        separator = ':';
 611                }
 612        }
 613
 614        /*
 615         * Don't do destructive transforms as protocol code does
 616         * '[]' unwrapping in get_host_and_port()
 617         */
 618        end = host_end(&host, 0);
 619
 620        if (protocol == PROTO_LOCAL)
 621                path = end;
 622        else if (protocol == PROTO_FILE && has_dos_drive_prefix(end))
 623                path = end; /* "file://$(pwd)" may be "file://C:/projects/repo" */
 624        else
 625                path = strchr(end, separator);
 626
 627        if (!path || !*path)
 628                die("No path specified. See 'man git-pull' for valid url syntax");
 629
 630        /*
 631         * null-terminate hostname and point path to ~ for URL's like this:
 632         *    ssh://host.xz/~user/repo
 633         */
 634
 635        end = path; /* Need to \0 terminate host here */
 636        if (separator == ':')
 637                path++; /* path starts after ':' */
 638        if (protocol == PROTO_GIT || protocol == PROTO_SSH) {
 639                if (path[1] == '~')
 640                        path++;
 641        }
 642
 643        path = xstrdup(path);
 644        *end = '\0';
 645
 646        *ret_host = xstrdup(host);
 647        *ret_path = path;
 648        free(url);
 649        return protocol;
 650}
 651
 652static struct child_process no_fork = CHILD_PROCESS_INIT;
 653
 654/*
 655 * This returns a dummy child_process if the transport protocol does not
 656 * need fork(2), or a struct child_process object if it does.  Once done,
 657 * finish the connection with finish_connect() with the value returned from
 658 * this function (it is safe to call finish_connect() with NULL to support
 659 * the former case).
 660 *
 661 * If it returns, the connect is successful; it just dies on errors (this
 662 * will hopefully be changed in a libification effort, to return NULL when
 663 * the connection failed).
 664 */
 665struct child_process *git_connect(int fd[2], const char *url,
 666                                  const char *prog, int flags)
 667{
 668        char *hostandport, *path;
 669        struct child_process *conn = &no_fork;
 670        enum protocol protocol;
 671        struct strbuf cmd = STRBUF_INIT;
 672
 673        /* Without this we cannot rely on waitpid() to tell
 674         * what happened to our children.
 675         */
 676        signal(SIGCHLD, SIG_DFL);
 677
 678        protocol = parse_connect_url(url, &hostandport, &path);
 679        if ((flags & CONNECT_DIAG_URL) && (protocol != PROTO_SSH)) {
 680                printf("Diag: url=%s\n", url ? url : "NULL");
 681                printf("Diag: protocol=%s\n", prot_name(protocol));
 682                printf("Diag: hostandport=%s\n", hostandport ? hostandport : "NULL");
 683                printf("Diag: path=%s\n", path ? path : "NULL");
 684                conn = NULL;
 685        } else if (protocol == PROTO_GIT) {
 686                /*
 687                 * Set up virtual host information based on where we will
 688                 * connect, unless the user has overridden us in
 689                 * the environment.
 690                 */
 691                char *target_host = getenv("GIT_OVERRIDE_VIRTUAL_HOST");
 692                if (target_host)
 693                        target_host = xstrdup(target_host);
 694                else
 695                        target_host = xstrdup(hostandport);
 696
 697                /* These underlying connection commands die() if they
 698                 * cannot connect.
 699                 */
 700                if (git_use_proxy(hostandport))
 701                        conn = git_proxy_connect(fd, hostandport);
 702                else
 703                        git_tcp_connect(fd, hostandport, flags);
 704                /*
 705                 * Separate original protocol components prog and path
 706                 * from extended host header with a NUL byte.
 707                 *
 708                 * Note: Do not add any other headers here!  Doing so
 709                 * will cause older git-daemon servers to crash.
 710                 */
 711                packet_write(fd[1],
 712                             "%s %s%chost=%s%c",
 713                             prog, path, 0,
 714                             target_host, 0);
 715                free(target_host);
 716        } else {
 717                conn = xmalloc(sizeof(*conn));
 718                child_process_init(conn);
 719
 720                strbuf_addstr(&cmd, prog);
 721                strbuf_addch(&cmd, ' ');
 722                sq_quote_buf(&cmd, path);
 723
 724                conn->in = conn->out = -1;
 725                if (protocol == PROTO_SSH) {
 726                        const char *ssh;
 727                        int putty, tortoiseplink = 0;
 728                        char *ssh_host = hostandport;
 729                        const char *port = NULL;
 730                        get_host_and_port(&ssh_host, &port);
 731
 732                        if (!port)
 733                                port = get_port(ssh_host);
 734
 735                        if (flags & CONNECT_DIAG_URL) {
 736                                printf("Diag: url=%s\n", url ? url : "NULL");
 737                                printf("Diag: protocol=%s\n", prot_name(protocol));
 738                                printf("Diag: userandhost=%s\n", ssh_host ? ssh_host : "NULL");
 739                                printf("Diag: port=%s\n", port ? port : "NONE");
 740                                printf("Diag: path=%s\n", path ? path : "NULL");
 741
 742                                free(hostandport);
 743                                free(path);
 744                                free(conn);
 745                                return NULL;
 746                        }
 747
 748                        ssh = getenv("GIT_SSH_COMMAND");
 749                        if (ssh) {
 750                                conn->use_shell = 1;
 751                                putty = 0;
 752                        } else {
 753                                const char *base;
 754                                char *ssh_dup;
 755
 756                                ssh = getenv("GIT_SSH");
 757                                if (!ssh)
 758                                        ssh = "ssh";
 759
 760                                ssh_dup = xstrdup(ssh);
 761                                base = basename(ssh_dup);
 762
 763                                tortoiseplink = !strcasecmp(base, "tortoiseplink") ||
 764                                        !strcasecmp(base, "tortoiseplink.exe");
 765                                putty = !strcasecmp(base, "plink") ||
 766                                        !strcasecmp(base, "plink.exe") || tortoiseplink;
 767
 768                                free(ssh_dup);
 769                        }
 770
 771                        argv_array_push(&conn->args, ssh);
 772                        if (tortoiseplink)
 773                                argv_array_push(&conn->args, "-batch");
 774                        if (port) {
 775                                /* P is for PuTTY, p is for OpenSSH */
 776                                argv_array_push(&conn->args, putty ? "-P" : "-p");
 777                                argv_array_push(&conn->args, port);
 778                        }
 779                        argv_array_push(&conn->args, ssh_host);
 780                } else {
 781                        /* remove repo-local variables from the environment */
 782                        conn->env = local_repo_env;
 783                        conn->use_shell = 1;
 784                }
 785                argv_array_push(&conn->args, cmd.buf);
 786
 787                if (start_command(conn))
 788                        die("unable to fork");
 789
 790                fd[0] = conn->out; /* read from child's stdout */
 791                fd[1] = conn->in;  /* write to child's stdin */
 792                strbuf_release(&cmd);
 793        }
 794        free(hostandport);
 795        free(path);
 796        return conn;
 797}
 798
 799int git_connection_is_socket(struct child_process *conn)
 800{
 801        return conn == &no_fork;
 802}
 803
 804int finish_connect(struct child_process *conn)
 805{
 806        int code;
 807        if (!conn || git_connection_is_socket(conn))
 808                return 0;
 809
 810        code = finish_command(conn);
 811        free(conn);
 812        return code;
 813}