git.oblomov.eu Git - git/blob - connect.c

   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 "version.h"
  16 #include "protocol.h"
  17
  18 static char *server_capabilities_v1;
  19 static struct argv_array server_capabilities_v2 = ARGV_ARRAY_INIT;
  20 static const char *parse_feature_value(const char *, const char *, int *);
  21
  22 static int check_ref(const char *name, unsigned int flags)
  23 {
  24         if (!flags)
  25                 return 1;
  26
  27         if (!skip_prefix(name, "refs/", &name))
  28                 return 0;
  29
  30         /* REF_NORMAL means that we don't want the magic fake tag refs */
  31         if ((flags & REF_NORMAL) && check_refname_format(name, 0))
  32                 return 0;
  33
  34         /* REF_HEADS means that we want regular branch heads */
  35         if ((flags & REF_HEADS) && starts_with(name, "heads/"))
  36                 return 1;
  37
  38         /* REF_TAGS means that we want tags */
  39         if ((flags & REF_TAGS) && starts_with(name, "tags/"))
  40                 return 1;
  41
  42         /* All type bits clear means that we are ok with anything */
  43         return !(flags & ~REF_NORMAL);
  44 }
  45
  46 int check_ref_type(const struct ref *ref, int flags)
  47 {
  48         return check_ref(ref->name, flags);
  49 }
  50
  51 static void die_initial_contact(int unexpected)
  52 {
  53         /*
  54          * A hang-up after seeing some response from the other end
  55          * means that it is unexpected, as we know the other end is
  56          * willing to talk to us.  A hang-up before seeing any
  57          * response does not necessarily mean an ACL problem, though.
  58          */
  59         if (unexpected)
  60                 die(_("The remote end hung up upon initial contact"));
  61         else
  62                 die(_("Could not read from remote repository.\n\n"
  63                       "Please make sure you have the correct access rights\n"
  64                       "and the repository exists."));
  65 }
  66
  67 /* Checks if the server supports the capability 'c' */
  68 int server_supports_v2(const char *c, int die_on_error)
  69 {
  70         int i;
  71
  72         for (i = 0; i < server_capabilities_v2.argc; i++) {
  73                 const char *out;
  74                 if (skip_prefix(server_capabilities_v2.argv[i], c, &out) &&
  75                     (!*out || *out == '='))
  76                         return 1;
  77         }
  78
  79         if (die_on_error)
  80                 die("server doesn't support '%s'", c);
  81
  82         return 0;
  83 }
  84
  85 static void process_capabilities_v2(struct packet_reader *reader)
  86 {
  87         while (packet_reader_read(reader) == PACKET_READ_NORMAL)
  88                 argv_array_push(&server_capabilities_v2, reader->line);
  89
  90         if (reader->status != PACKET_READ_FLUSH)
  91                 die("expected flush after capabilities");
  92 }
  93
  94 enum protocol_version discover_version(struct packet_reader *reader)
  95 {
  96         enum protocol_version version = protocol_unknown_version;
  97
  98         /*
  99          * Peek the first line of the server's response to
 100          * determine the protocol version the server is speaking.
 101          */
 102         switch (packet_reader_peek(reader)) {
 103         case PACKET_READ_EOF:
 104                 die_initial_contact(0);
 105         case PACKET_READ_FLUSH:
 106         case PACKET_READ_DELIM:
 107                 version = protocol_v0;
 108                 break;
 109         case PACKET_READ_NORMAL:
 110                 version = determine_protocol_version_client(reader->line);
 111                 break;
 112         }
 113
 114         switch (version) {
 115         case protocol_v2:
 116                 process_capabilities_v2(reader);
 117                 break;
 118         case protocol_v1:
 119                 /* Read the peeked version line */
 120                 packet_reader_read(reader);
 121                 break;
 122         case protocol_v0:
 123                 break;
 124         case protocol_unknown_version:
 125                 BUG("unknown protocol version");
 126         }
 127
 128         return version;
 129 }
 130
 131 static void parse_one_symref_info(struct string_list *symref, const char *val, int len)
 132 {
 133         char *sym, *target;
 134         struct string_list_item *item;
 135
 136         if (!len)
 137                 return; /* just "symref" */
 138         /* e.g. "symref=HEAD:refs/heads/master" */
 139         sym = xmemdupz(val, len);
 140         target = strchr(sym, ':');
 141         if (!target)
 142                 /* just "symref=something" */
 143                 goto reject;
 144         *(target++) = '\0';
 145         if (check_refname_format(sym, REFNAME_ALLOW_ONELEVEL) ||
 146             check_refname_format(target, REFNAME_ALLOW_ONELEVEL))
 147                 /* "symref=bogus:pair */
 148                 goto reject;
 149         item = string_list_append_nodup(symref, sym);
 150         item->util = target;
 151         return;
 152 reject:
 153         free(sym);
 154         return;
 155 }
 156
 157 static void annotate_refs_with_symref_info(struct ref *ref)
 158 {
 159         struct string_list symref = STRING_LIST_INIT_DUP;
 160         const char *feature_list = server_capabilities_v1;
 161
 162         while (feature_list) {
 163                 int len;
 164                 const char *val;
 165
 166                 val = parse_feature_value(feature_list, "symref", &len);
 167                 if (!val)
 168                         break;
 169                 parse_one_symref_info(&symref, val, len);
 170                 feature_list = val + 1;
 171         }
 172         string_list_sort(&symref);
 173
 174         for (; ref; ref = ref->next) {
 175                 struct string_list_item *item;
 176                 item = string_list_lookup(&symref, ref->name);
 177                 if (!item)
 178                         continue;
 179                 ref->symref = xstrdup((char *)item->util);
 180         }
 181         string_list_clear(&symref, 0);
 182 }
 183
 184 static void process_capabilities(const char *line, int *len)
 185 {
 186         int nul_location = strlen(line);
 187         if (nul_location == *len)
 188                 return;
 189         server_capabilities_v1 = xstrdup(line + nul_location + 1);
 190         *len = nul_location;
 191 }
 192
 193 static int process_dummy_ref(const char *line)
 194 {
 195         struct object_id oid;
 196         const char *name;
 197
 198         if (parse_oid_hex(line, &oid, &name))
 199                 return 0;
 200         if (*name != ' ')
 201                 return 0;
 202         name++;
 203
 204         return !oidcmp(&null_oid, &oid) && !strcmp(name, "capabilities^{}");
 205 }
 206
 207 static void check_no_capabilities(const char *line, int len)
 208 {
 209         if (strlen(line) != len)
 210                 warning("Ignoring capabilities after first line '%s'",
 211                         line + strlen(line));
 212 }
 213
 214 static int process_ref(const char *line, int len, struct ref ***list,
 215                        unsigned int flags, struct oid_array *extra_have)
 216 {
 217         struct object_id old_oid;
 218         const char *name;
 219
 220         if (parse_oid_hex(line, &old_oid, &name))
 221                 return 0;
 222         if (*name != ' ')
 223                 return 0;
 224         name++;
 225
 226         if (extra_have && !strcmp(name, ".have")) {
 227                 oid_array_append(extra_have, &old_oid);
 228         } else if (!strcmp(name, "capabilities^{}")) {
 229                 die("protocol error: unexpected capabilities^{}");
 230         } else if (check_ref(name, flags)) {
 231                 struct ref *ref = alloc_ref(name);
 232                 oidcpy(&ref->old_oid, &old_oid);
 233                 **list = ref;
 234                 *list = &ref->next;
 235         }
 236         check_no_capabilities(line, len);
 237         return 1;
 238 }
 239
 240 static int process_shallow(const char *line, int len,
 241                            struct oid_array *shallow_points)
 242 {
 243         const char *arg;
 244         struct object_id old_oid;
 245
 246         if (!skip_prefix(line, "shallow ", &arg))
 247                 return 0;
 248
 249         if (get_oid_hex(arg, &old_oid))
 250                 die("protocol error: expected shallow sha-1, got '%s'", arg);
 251         if (!shallow_points)
 252                 die("repository on the other end cannot be shallow");
 253         oid_array_append(shallow_points, &old_oid);
 254         check_no_capabilities(line, len);
 255         return 1;
 256 }
 257
 258 enum get_remote_heads_state {
 259         EXPECTING_FIRST_REF = 0,
 260         EXPECTING_REF,
 261         EXPECTING_SHALLOW,
 262         EXPECTING_DONE,
 263 };
 264
 265 /*
 266  * Read all the refs from the other end
 267  */
 268 struct ref **get_remote_heads(struct packet_reader *reader,
 269                               struct ref **list, unsigned int flags,
 270                               struct oid_array *extra_have,
 271                               struct oid_array *shallow_points)
 272 {
 273         struct ref **orig_list = list;
 274         int len = 0;
 275         enum get_remote_heads_state state = EXPECTING_FIRST_REF;
 276         const char *arg;
 277
 278         *list = NULL;
 279
 280         while (state != EXPECTING_DONE) {
 281                 switch (packet_reader_read(reader)) {
 282                 case PACKET_READ_EOF:
 283                         die_initial_contact(1);
 284                 case PACKET_READ_NORMAL:
 285                         len = reader->pktlen;
 286                         if (len > 4 && skip_prefix(reader->line, "ERR ", &arg))
 287                                 die("remote error: %s", arg);
 288                         break;
 289                 case PACKET_READ_FLUSH:
 290                         state = EXPECTING_DONE;
 291                         break;
 292                 case PACKET_READ_DELIM:
 293                         die("invalid packet");
 294                 }
 295
 296                 switch (state) {
 297                 case EXPECTING_FIRST_REF:
 298                         process_capabilities(reader->line, &len);
 299                         if (process_dummy_ref(reader->line)) {
 300                                 state = EXPECTING_SHALLOW;
 301                                 break;
 302                         }
 303                         state = EXPECTING_REF;
 304                         /* fallthrough */
 305                 case EXPECTING_REF:
 306                         if (process_ref(reader->line, len, &list, flags, extra_have))
 307                                 break;
 308                         state = EXPECTING_SHALLOW;
 309                         /* fallthrough */
 310                 case EXPECTING_SHALLOW:
 311                         if (process_shallow(reader->line, len, shallow_points))
 312                                 break;
 313                         die("protocol error: unexpected '%s'", reader->line);
 314                 case EXPECTING_DONE:
 315                         break;
 316                 }
 317         }
 318
 319         annotate_refs_with_symref_info(*orig_list);
 320
 321         return list;
 322 }
 323
 324 /* Returns 1 when a valid ref has been added to `list`, 0 otherwise */
 325 static int process_ref_v2(const char *line, struct ref ***list)
 326 {
 327         int ret = 1;
 328         int i = 0;
 329         struct object_id old_oid;
 330         struct ref *ref;
 331         struct string_list line_sections = STRING_LIST_INIT_DUP;
 332         const char *end;
 333
 334         /*
 335          * Ref lines have a number of fields which are space deliminated.  The
 336          * first field is the OID of the ref.  The second field is the ref
 337          * name.  Subsequent fields (symref-target and peeled) are optional and
 338          * don't have a particular order.
 339          */
 340         if (string_list_split(&line_sections, line, ' ', -1) < 2) {
 341                 ret = 0;
 342                 goto out;
 343         }
 344
 345         if (parse_oid_hex(line_sections.items[i++].string, &old_oid, &end) ||
 346             *end) {
 347                 ret = 0;
 348                 goto out;
 349         }
 350
 351         ref = alloc_ref(line_sections.items[i++].string);
 352
 353         oidcpy(&ref->old_oid, &old_oid);
 354         **list = ref;
 355         *list = &ref->next;
 356
 357         for (; i < line_sections.nr; i++) {
 358                 const char *arg = line_sections.items[i].string;
 359                 if (skip_prefix(arg, "symref-target:", &arg))
 360                         ref->symref = xstrdup(arg);
 361
 362                 if (skip_prefix(arg, "peeled:", &arg)) {
 363                         struct object_id peeled_oid;
 364                         char *peeled_name;
 365                         struct ref *peeled;
 366                         if (parse_oid_hex(arg, &peeled_oid, &end) || *end) {
 367                                 ret = 0;
 368                                 goto out;
 369                         }
 370
 371                         peeled_name = xstrfmt("%s^{}", ref->name);
 372                         peeled = alloc_ref(peeled_name);
 373
 374                         oidcpy(&peeled->old_oid, &peeled_oid);
 375                         **list = peeled;
 376                         *list = &peeled->next;
 377
 378                         free(peeled_name);
 379                 }
 380         }
 381
 382 out:
 383         string_list_clear(&line_sections, 0);
 384         return ret;
 385 }
 386
 387 struct ref **get_remote_refs(int fd_out, struct packet_reader *reader,
 388                              struct ref **list, int for_push,
 389                              const struct argv_array *ref_prefixes)
 390 {
 391         int i;
 392         *list = NULL;
 393
 394         if (server_supports_v2("ls-refs", 1))
 395                 packet_write_fmt(fd_out, "command=ls-refs\n");
 396
 397         if (server_supports_v2("agent", 0))
 398                 packet_write_fmt(fd_out, "agent=%s", git_user_agent_sanitized());
 399
 400         packet_delim(fd_out);
 401         /* When pushing we don't want to request the peeled tags */
 402         if (!for_push)
 403                 packet_write_fmt(fd_out, "peel\n");
 404         packet_write_fmt(fd_out, "symrefs\n");
 405         for (i = 0; ref_prefixes && i < ref_prefixes->argc; i++) {
 406                 packet_write_fmt(fd_out, "ref-prefix %s\n",
 407                                  ref_prefixes->argv[i]);
 408         }
 409         packet_flush(fd_out);
 410
 411         /* Process response from server */
 412         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
 413                 if (!process_ref_v2(reader->line, &list))
 414                         die("invalid ls-refs response: %s", reader->line);
 415         }
 416
 417         if (reader->status != PACKET_READ_FLUSH)
 418                 die("expected flush after ref listing");
 419
 420         return list;
 421 }
 422
 423 static const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
 424 {
 425         int len;
 426
 427         if (!feature_list)
 428                 return NULL;
 429
 430         len = strlen(feature);
 431         while (*feature_list) {
 432                 const char *found = strstr(feature_list, feature);
 433                 if (!found)
 434                         return NULL;
 435                 if (feature_list == found || isspace(found[-1])) {
 436                         const char *value = found + len;
 437                         /* feature with no value (e.g., "thin-pack") */
 438                         if (!*value || isspace(*value)) {
 439                                 if (lenp)
 440                                         *lenp = 0;
 441                                 return value;
 442                         }
 443                         /* feature with a value (e.g., "agent=git/1.2.3") */
 444                         else if (*value == '=') {
 445                                 value++;
 446                                 if (lenp)
 447                                         *lenp = strcspn(value, " \t\n");
 448                                 return value;
 449                         }
 450                         /*
 451                          * otherwise we matched a substring of another feature;
 452                          * keep looking
 453                          */
 454                 }
 455                 feature_list = found + 1;
 456         }
 457         return NULL;
 458 }
 459
 460 int parse_feature_request(const char *feature_list, const char *feature)
 461 {
 462         return !!parse_feature_value(feature_list, feature, NULL);
 463 }
 464
 465 const char *server_feature_value(const char *feature, int *len)
 466 {
 467         return parse_feature_value(server_capabilities_v1, feature, len);
 468 }
 469
 470 int server_supports(const char *feature)
 471 {
 472         return !!server_feature_value(feature, NULL);
 473 }
 474
 475 enum protocol {
 476         PROTO_LOCAL = 1,
 477         PROTO_FILE,
 478         PROTO_SSH,
 479         PROTO_GIT
 480 };
 481
 482 int url_is_local_not_ssh(const char *url)
 483 {
 484         const char *colon = strchr(url, ':');
 485         const char *slash = strchr(url, '/');
 486         return !colon || (slash && slash < colon) ||
 487                 has_dos_drive_prefix(url);
 488 }
 489
 490 static const char *prot_name(enum protocol protocol)
 491 {
 492         switch (protocol) {
 493                 case PROTO_LOCAL:
 494                 case PROTO_FILE:
 495                         return "file";
 496                 case PROTO_SSH:
 497                         return "ssh";
 498                 case PROTO_GIT:
 499                         return "git";
 500                 default:
 501                         return "unknown protocol";
 502         }
 503 }
 504
 505 static enum protocol get_protocol(const char *name)
 506 {
 507         if (!strcmp(name, "ssh"))
 508                 return PROTO_SSH;
 509         if (!strcmp(name, "git"))
 510                 return PROTO_GIT;
 511         if (!strcmp(name, "git+ssh")) /* deprecated - do not use */
 512                 return PROTO_SSH;
 513         if (!strcmp(name, "ssh+git")) /* deprecated - do not use */
 514                 return PROTO_SSH;
 515         if (!strcmp(name, "file"))
 516                 return PROTO_FILE;
 517         die("I don't handle protocol '%s'", name);
 518 }
 519
 520 static char *host_end(char **hoststart, int removebrackets)
 521 {
 522         char *host = *hoststart;
 523         char *end;
 524         char *start = strstr(host, "@[");
 525         if (start)
 526                 start++; /* Jump over '@' */
 527         else
 528                 start = host;
 529         if (start[0] == '[') {
 530                 end = strchr(start + 1, ']');
 531                 if (end) {
 532                         if (removebrackets) {
 533                                 *end = 0;
 534                                 memmove(start, start + 1, end - start);
 535                                 end++;
 536                         }
 537                 } else
 538                         end = host;
 539         } else
 540                 end = host;
 541         return end;
 542 }
 543
 544 #define STR_(s) # s
 545 #define STR(s)  STR_(s)
 546
 547 static void get_host_and_port(char **host, const char **port)
 548 {
 549         char *colon, *end;
 550         end = host_end(host, 1);
 551         colon = strchr(end, ':');
 552         if (colon) {
 553                 long portnr = strtol(colon + 1, &end, 10);
 554                 if (end != colon + 1 && *end == '\0' && 0 <= portnr && portnr < 65536) {
 555                         *colon = 0;
 556                         *port = colon + 1;
 557                 } else if (!colon[1]) {
 558                         *colon = 0;
 559                 }
 560         }
 561 }
 562
 563 static void enable_keepalive(int sockfd)
 564 {
 565         int ka = 1;
 566
 567         if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
 568                 fprintf(stderr, "unable to set SO_KEEPALIVE on socket: %s\n",
 569                         strerror(errno));
 570 }
 571
 572 #ifndef NO_IPV6
 573
 574 static const char *ai_name(const struct addrinfo *ai)
 575 {
 576         static char addr[NI_MAXHOST];
 577         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
 578                         NI_NUMERICHOST) != 0)
 579                 xsnprintf(addr, sizeof(addr), "(unknown)");
 580
 581         return addr;
 582 }
 583
 584 /*
 585  * Returns a connected socket() fd, or else die()s.
 586  */
 587 static int git_tcp_connect_sock(char *host, int flags)
 588 {
 589         struct strbuf error_message = STRBUF_INIT;
 590         int sockfd = -1;
 591         const char *port = STR(DEFAULT_GIT_PORT);
 592         struct addrinfo hints, *ai0, *ai;
 593         int gai;
 594         int cnt = 0;
 595
 596         get_host_and_port(&host, &port);
 597         if (!*port)
 598                 port = "<none>";
 599
 600         memset(&hints, 0, sizeof(hints));
 601         if (flags & CONNECT_IPV4)
 602                 hints.ai_family = AF_INET;
 603         else if (flags & CONNECT_IPV6)
 604                 hints.ai_family = AF_INET6;
 605         hints.ai_socktype = SOCK_STREAM;
 606         hints.ai_protocol = IPPROTO_TCP;
 607
 608         if (flags & CONNECT_VERBOSE)
 609                 fprintf(stderr, "Looking up %s ... ", host);
 610
 611         gai = getaddrinfo(host, port, &hints, &ai);
 612         if (gai)
 613                 die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
 614
 615         if (flags & CONNECT_VERBOSE)
 616                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 617
 618         for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
 619                 sockfd = socket(ai->ai_family,
 620                                 ai->ai_socktype, ai->ai_protocol);
 621                 if ((sockfd < 0) ||
 622                     (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
 623                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 624                                     host, cnt, ai_name(ai), strerror(errno));
 625                         if (0 <= sockfd)
 626                                 close(sockfd);
 627                         sockfd = -1;
 628                         continue;
 629                 }
 630                 if (flags & CONNECT_VERBOSE)
 631                         fprintf(stderr, "%s ", ai_name(ai));
 632                 break;
 633         }
 634
 635         freeaddrinfo(ai0);
 636
 637         if (sockfd < 0)
 638                 die("unable to connect to %s:\n%s", host, error_message.buf);
 639
 640         enable_keepalive(sockfd);
 641
 642         if (flags & CONNECT_VERBOSE)
 643                 fprintf(stderr, "done.\n");
 644
 645         strbuf_release(&error_message);
 646
 647         return sockfd;
 648 }
 649
 650 #else /* NO_IPV6 */
 651
 652 /*
 653  * Returns a connected socket() fd, or else die()s.
 654  */
 655 static int git_tcp_connect_sock(char *host, int flags)
 656 {
 657         struct strbuf error_message = STRBUF_INIT;
 658         int sockfd = -1;
 659         const char *port = STR(DEFAULT_GIT_PORT);
 660         char *ep;
 661         struct hostent *he;
 662         struct sockaddr_in sa;
 663         char **ap;
 664         unsigned int nport;
 665         int cnt;
 666
 667         get_host_and_port(&host, &port);
 668
 669         if (flags & CONNECT_VERBOSE)
 670                 fprintf(stderr, "Looking up %s ... ", host);
 671
 672         he = gethostbyname(host);
 673         if (!he)
 674                 die("Unable to look up %s (%s)", host, hstrerror(h_errno));
 675         nport = strtoul(port, &ep, 10);
 676         if ( ep == port || *ep ) {
 677                 /* Not numeric */
 678                 struct servent *se = getservbyname(port,"tcp");
 679                 if ( !se )
 680                         die("Unknown port %s", port);
 681                 nport = se->s_port;
 682         }
 683
 684         if (flags & CONNECT_VERBOSE)
 685                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 686
 687         for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
 688                 memset(&sa, 0, sizeof sa);
 689                 sa.sin_family = he->h_addrtype;
 690                 sa.sin_port = htons(nport);
 691                 memcpy(&sa.sin_addr, *ap, he->h_length);
 692
 693                 sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 694                 if ((sockfd < 0) ||
 695                     connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 696                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 697                                 host,
 698                                 cnt,
 699                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr),
 700                                 strerror(errno));
 701                         if (0 <= sockfd)
 702                                 close(sockfd);
 703                         sockfd = -1;
 704                         continue;
 705                 }
 706                 if (flags & CONNECT_VERBOSE)
 707                         fprintf(stderr, "%s ",
 708                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr));
 709                 break;
 710         }
 711
 712         if (sockfd < 0)
 713                 die("unable to connect to %s:\n%s", host, error_message.buf);
 714
 715         enable_keepalive(sockfd);
 716
 717         if (flags & CONNECT_VERBOSE)
 718                 fprintf(stderr, "done.\n");
 719
 720         return sockfd;
 721 }
 722
 723 #endif /* NO_IPV6 */
 724
 725
 726 /*
 727  * Dummy child_process returned by git_connect() if the transport protocol
 728  * does not need fork(2).
 729  */
 730 static struct child_process no_fork = CHILD_PROCESS_INIT;
 731
 732 int git_connection_is_socket(struct child_process *conn)
 733 {
 734         return conn == &no_fork;
 735 }
 736
 737 static struct child_process *git_tcp_connect(int fd[2], char *host, int flags)
 738 {
 739         int sockfd = git_tcp_connect_sock(host, flags);
 740
 741         fd[0] = sockfd;
 742         fd[1] = dup(sockfd);
 743
 744         return &no_fork;
 745 }
 746
 747
 748 static char *git_proxy_command;
 749
 750 static int git_proxy_command_options(const char *var, const char *value,
 751                 void *cb)
 752 {
 753         if (!strcmp(var, "core.gitproxy")) {
 754                 const char *for_pos;
 755                 int matchlen = -1;
 756                 int hostlen;
 757                 const char *rhost_name = cb;
 758                 int rhost_len = strlen(rhost_name);
 759
 760                 if (git_proxy_command)
 761                         return 0;
 762                 if (!value)
 763                         return config_error_nonbool(var);
 764                 /* [core]
 765                  * ;# matches www.kernel.org as well
 766                  * gitproxy = netcatter-1 for kernel.org
 767                  * gitproxy = netcatter-2 for sample.xz
 768                  * gitproxy = netcatter-default
 769                  */
 770                 for_pos = strstr(value, " for ");
 771                 if (!for_pos)
 772                         /* matches everybody */
 773                         matchlen = strlen(value);
 774                 else {
 775                         hostlen = strlen(for_pos + 5);
 776                         if (rhost_len < hostlen)
 777                                 matchlen = -1;
 778                         else if (!strncmp(for_pos + 5,
 779                                           rhost_name + rhost_len - hostlen,
 780                                           hostlen) &&
 781                                  ((rhost_len == hostlen) ||
 782                                   rhost_name[rhost_len - hostlen -1] == '.'))
 783                                 matchlen = for_pos - value;
 784                         else
 785                                 matchlen = -1;
 786                 }
 787                 if (0 <= matchlen) {
 788                         /* core.gitproxy = none for kernel.org */
 789                         if (matchlen == 4 &&
 790                             !memcmp(value, "none", 4))
 791                                 matchlen = 0;
 792                         git_proxy_command = xmemdupz(value, matchlen);
 793                 }
 794                 return 0;
 795         }
 796
 797         return git_default_config(var, value, cb);
 798 }
 799
 800 static int git_use_proxy(const char *host)
 801 {
 802         git_proxy_command = getenv("GIT_PROXY_COMMAND");
 803         git_config(git_proxy_command_options, (void*)host);
 804         return (git_proxy_command && *git_proxy_command);
 805 }
 806
 807 static struct child_process *git_proxy_connect(int fd[2], char *host)
 808 {
 809         const char *port = STR(DEFAULT_GIT_PORT);
 810         struct child_process *proxy;
 811
 812         get_host_and_port(&host, &port);
 813
 814         if (looks_like_command_line_option(host))
 815                 die("strange hostname '%s' blocked", host);
 816         if (looks_like_command_line_option(port))
 817                 die("strange port '%s' blocked", port);
 818
 819         proxy = xmalloc(sizeof(*proxy));
 820         child_process_init(proxy);
 821         argv_array_push(&proxy->args, git_proxy_command);
 822         argv_array_push(&proxy->args, host);
 823         argv_array_push(&proxy->args, port);
 824         proxy->in = -1;
 825         proxy->out = -1;
 826         if (start_command(proxy))
 827                 die("cannot start proxy %s", git_proxy_command);
 828         fd[0] = proxy->out; /* read from proxy stdout */
 829         fd[1] = proxy->in;  /* write to proxy stdin */
 830         return proxy;
 831 }
 832
 833 static char *get_port(char *host)
 834 {
 835         char *end;
 836         char *p = strchr(host, ':');
 837
 838         if (p) {
 839                 long port = strtol(p + 1, &end, 10);
 840                 if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
 841                         *p = '\0';
 842                         return p+1;
 843                 }
 844         }
 845
 846         return NULL;
 847 }
 848
 849 /*
 850  * Extract protocol and relevant parts from the specified connection URL.
 851  * The caller must free() the returned strings.
 852  */
 853 static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
 854                                        char **ret_path)
 855 {
 856         char *url;
 857         char *host, *path;
 858         char *end;
 859         int separator = '/';
 860         enum protocol protocol = PROTO_LOCAL;
 861
 862         if (is_url(url_orig))
 863                 url = url_decode(url_orig);
 864         else
 865                 url = xstrdup(url_orig);
 866
 867         host = strstr(url, "://");
 868         if (host) {
 869                 *host = '\0';
 870                 protocol = get_protocol(url);
 871                 host += 3;
 872         } else {
 873                 host = url;
 874                 if (!url_is_local_not_ssh(url)) {
 875                         protocol = PROTO_SSH;
 876                         separator = ':';
 877                 }
 878         }
 879
 880         /*
 881          * Don't do destructive transforms as protocol code does
 882          * '[]' unwrapping in get_host_and_port()
 883          */
 884         end = host_end(&host, 0);
 885
 886         if (protocol == PROTO_LOCAL)
 887                 path = end;
 888         else if (protocol == PROTO_FILE && has_dos_drive_prefix(end))
 889                 path = end; /* "file://$(pwd)" may be "file://C:/projects/repo" */
 890         else
 891                 path = strchr(end, separator);
 892
 893         if (!path || !*path)
 894                 die("No path specified. See 'man git-pull' for valid url syntax");
 895
 896         /*
 897          * null-terminate hostname and point path to ~ for URL's like this:
 898          *    ssh://host.xz/~user/repo
 899          */
 900
 901         end = path; /* Need to \0 terminate host here */
 902         if (separator == ':')
 903                 path++; /* path starts after ':' */
 904         if (protocol == PROTO_GIT || protocol == PROTO_SSH) {
 905                 if (path[1] == '~')
 906                         path++;
 907         }
 908
 909         path = xstrdup(path);
 910         *end = '\0';
 911
 912         *ret_host = xstrdup(host);
 913         *ret_path = path;
 914         free(url);
 915         return protocol;
 916 }
 917
 918 static const char *get_ssh_command(void)
 919 {
 920         const char *ssh;
 921
 922         if ((ssh = getenv("GIT_SSH_COMMAND")))
 923                 return ssh;
 924
 925         if (!git_config_get_string_const("core.sshcommand", &ssh))
 926                 return ssh;
 927
 928         return NULL;
 929 }
 930
 931 enum ssh_variant {
 932         VARIANT_AUTO,
 933         VARIANT_SIMPLE,
 934         VARIANT_SSH,
 935         VARIANT_PLINK,
 936         VARIANT_PUTTY,
 937         VARIANT_TORTOISEPLINK,
 938 };
 939
 940 static void override_ssh_variant(enum ssh_variant *ssh_variant)
 941 {
 942         const char *variant = getenv("GIT_SSH_VARIANT");
 943
 944         if (!variant && git_config_get_string_const("ssh.variant", &variant))
 945                 return;
 946
 947         if (!strcmp(variant, "auto"))
 948                 *ssh_variant = VARIANT_AUTO;
 949         else if (!strcmp(variant, "plink"))
 950                 *ssh_variant = VARIANT_PLINK;
 951         else if (!strcmp(variant, "putty"))
 952                 *ssh_variant = VARIANT_PUTTY;
 953         else if (!strcmp(variant, "tortoiseplink"))
 954                 *ssh_variant = VARIANT_TORTOISEPLINK;
 955         else if (!strcmp(variant, "simple"))
 956                 *ssh_variant = VARIANT_SIMPLE;
 957         else
 958                 *ssh_variant = VARIANT_SSH;
 959 }
 960
 961 static enum ssh_variant determine_ssh_variant(const char *ssh_command,
 962                                               int is_cmdline)
 963 {
 964         enum ssh_variant ssh_variant = VARIANT_AUTO;
 965         const char *variant;
 966         char *p = NULL;
 967
 968         override_ssh_variant(&ssh_variant);
 969
 970         if (ssh_variant != VARIANT_AUTO)
 971                 return ssh_variant;
 972
 973         if (!is_cmdline) {
 974                 p = xstrdup(ssh_command);
 975                 variant = basename(p);
 976         } else {
 977                 const char **ssh_argv;
 978
 979                 p = xstrdup(ssh_command);
 980                 if (split_cmdline(p, &ssh_argv) > 0) {
 981                         variant = basename((char *)ssh_argv[0]);
 982                         /*
 983                          * At this point, variant points into the buffer
 984                          * referenced by p, hence we do not need ssh_argv
 985                          * any longer.
 986                          */
 987                         free(ssh_argv);
 988                 } else {
 989                         free(p);
 990                         return ssh_variant;
 991                 }
 992         }
 993
 994         if (!strcasecmp(variant, "ssh") ||
 995             !strcasecmp(variant, "ssh.exe"))
 996                 ssh_variant = VARIANT_SSH;
 997         else if (!strcasecmp(variant, "plink") ||
 998                  !strcasecmp(variant, "plink.exe"))
 999                 ssh_variant = VARIANT_PLINK;
1000         else if (!strcasecmp(variant, "tortoiseplink") ||
1001                  !strcasecmp(variant, "tortoiseplink.exe"))
1002                 ssh_variant = VARIANT_TORTOISEPLINK;
1003
1004         free(p);
1005         return ssh_variant;
1006 }
1007
1008 /*
1009  * Open a connection using Git's native protocol.
1010  *
1011  * The caller is responsible for freeing hostandport, but this function may
1012  * modify it (for example, to truncate it to remove the port part).
1013  */
1014 static struct child_process *git_connect_git(int fd[2], char *hostandport,
1015                                              const char *path, const char *prog,
1016                                              int flags)
1017 {
1018         struct child_process *conn;
1019         struct strbuf request = STRBUF_INIT;
1020         /*
1021          * Set up virtual host information based on where we will
1022          * connect, unless the user has overridden us in
1023          * the environment.
1024          */
1025         char *target_host = getenv("GIT_OVERRIDE_VIRTUAL_HOST");
1026         if (target_host)
1027                 target_host = xstrdup(target_host);
1028         else
1029                 target_host = xstrdup(hostandport);
1030
1031         transport_check_allowed("git");
1032
1033         /*
1034          * These underlying connection commands die() if they
1035          * cannot connect.
1036          */
1037         if (git_use_proxy(hostandport))
1038                 conn = git_proxy_connect(fd, hostandport);
1039         else
1040                 conn = git_tcp_connect(fd, hostandport, flags);
1041         /*
1042          * Separate original protocol components prog and path
1043          * from extended host header with a NUL byte.
1044          *
1045          * Note: Do not add any other headers here!  Doing so
1046          * will cause older git-daemon servers to crash.
1047          */
1048         strbuf_addf(&request,
1049                     "%s %s%chost=%s%c",
1050                     prog, path, 0,
1051                     target_host, 0);
1052
1053         /* If using a new version put that stuff here after a second null byte */
1054         if (get_protocol_version_config() > 0) {
1055                 strbuf_addch(&request, '\0');
1056                 strbuf_addf(&request, "version=%d%c",
1057                             get_protocol_version_config(), '\0');
1058         }
1059
1060         packet_write(fd[1], request.buf, request.len);
1061
1062         free(target_host);
1063         strbuf_release(&request);
1064         return conn;
1065 }
1066
1067 /*
1068  * Append the appropriate environment variables to `env` and options to
1069  * `args` for running ssh in Git's SSH-tunneled transport.
1070  */
1071 static void push_ssh_options(struct argv_array *args, struct argv_array *env,
1072                              enum ssh_variant variant, const char *port,
1073                              int flags)
1074 {
1075         if (variant == VARIANT_SSH &&
1076             get_protocol_version_config() > 0) {
1077                 argv_array_push(args, "-o");
1078                 argv_array_push(args, "SendEnv=" GIT_PROTOCOL_ENVIRONMENT);
1079                 argv_array_pushf(env, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
1080                                  get_protocol_version_config());
1081         }
1082
1083         if (flags & CONNECT_IPV4) {
1084                 switch (variant) {
1085                 case VARIANT_AUTO:
1086                         BUG("VARIANT_AUTO passed to push_ssh_options");
1087                 case VARIANT_SIMPLE:
1088                         die("ssh variant 'simple' does not support -4");
1089                 case VARIANT_SSH:
1090                 case VARIANT_PLINK:
1091                 case VARIANT_PUTTY:
1092                 case VARIANT_TORTOISEPLINK:
1093                         argv_array_push(args, "-4");
1094                 }
1095         } else if (flags & CONNECT_IPV6) {
1096                 switch (variant) {
1097                 case VARIANT_AUTO:
1098                         BUG("VARIANT_AUTO passed to push_ssh_options");
1099                 case VARIANT_SIMPLE:
1100                         die("ssh variant 'simple' does not support -6");
1101                 case VARIANT_SSH:
1102                 case VARIANT_PLINK:
1103                 case VARIANT_PUTTY:
1104                 case VARIANT_TORTOISEPLINK:
1105                         argv_array_push(args, "-6");
1106                 }
1107         }
1108
1109         if (variant == VARIANT_TORTOISEPLINK)
1110                 argv_array_push(args, "-batch");
1111
1112         if (port) {
1113                 switch (variant) {
1114                 case VARIANT_AUTO:
1115                         BUG("VARIANT_AUTO passed to push_ssh_options");
1116                 case VARIANT_SIMPLE:
1117                         die("ssh variant 'simple' does not support setting port");
1118                 case VARIANT_SSH:
1119                         argv_array_push(args, "-p");
1120                         break;
1121                 case VARIANT_PLINK:
1122                 case VARIANT_PUTTY:
1123                 case VARIANT_TORTOISEPLINK:
1124                         argv_array_push(args, "-P");
1125                 }
1126
1127                 argv_array_push(args, port);
1128         }
1129 }
1130
1131 /* Prepare a child_process for use by Git's SSH-tunneled transport. */
1132 static void fill_ssh_args(struct child_process *conn, const char *ssh_host,
1133                           const char *port, int flags)
1134 {
1135         const char *ssh;
1136         enum ssh_variant variant;
1137
1138         if (looks_like_command_line_option(ssh_host))
1139                 die("strange hostname '%s' blocked", ssh_host);
1140
1141         ssh = get_ssh_command();
1142         if (ssh) {
1143                 variant = determine_ssh_variant(ssh, 1);
1144         } else {
1145                 /*
1146                  * GIT_SSH is the no-shell version of
1147                  * GIT_SSH_COMMAND (and must remain so for
1148                  * historical compatibility).
1149                  */
1150                 conn->use_shell = 0;
1151
1152                 ssh = getenv("GIT_SSH");
1153                 if (!ssh)
1154                         ssh = "ssh";
1155                 variant = determine_ssh_variant(ssh, 0);
1156         }
1157
1158         if (variant == VARIANT_AUTO) {
1159                 struct child_process detect = CHILD_PROCESS_INIT;
1160
1161                 detect.use_shell = conn->use_shell;
1162                 detect.no_stdin = detect.no_stdout = detect.no_stderr = 1;
1163
1164                 argv_array_push(&detect.args, ssh);
1165                 argv_array_push(&detect.args, "-G");
1166                 push_ssh_options(&detect.args, &detect.env_array,
1167                                  VARIANT_SSH, port, flags);
1168                 argv_array_push(&detect.args, ssh_host);
1169
1170                 variant = run_command(&detect) ? VARIANT_SIMPLE : VARIANT_SSH;
1171         }
1172
1173         argv_array_push(&conn->args, ssh);
1174         push_ssh_options(&conn->args, &conn->env_array, variant, port, flags);
1175         argv_array_push(&conn->args, ssh_host);
1176 }
1177
1178 /*
1179  * This returns the dummy child_process `no_fork` if the transport protocol
1180  * does not need fork(2), or a struct child_process object if it does.  Once
1181  * done, finish the connection with finish_connect() with the value returned
1182  * from this function (it is safe to call finish_connect() with NULL to
1183  * support the former case).
1184  *
1185  * If it returns, the connect is successful; it just dies on errors (this
1186  * will hopefully be changed in a libification effort, to return NULL when
1187  * the connection failed).
1188  */
1189 struct child_process *git_connect(int fd[2], const char *url,
1190                                   const char *prog, int flags)
1191 {
1192         char *hostandport, *path;
1193         struct child_process *conn;
1194         enum protocol protocol;
1195
1196         /* Without this we cannot rely on waitpid() to tell
1197          * what happened to our children.
1198          */
1199         signal(SIGCHLD, SIG_DFL);
1200
1201         protocol = parse_connect_url(url, &hostandport, &path);
1202         if ((flags & CONNECT_DIAG_URL) && (protocol != PROTO_SSH)) {
1203                 printf("Diag: url=%s\n", url ? url : "NULL");
1204                 printf("Diag: protocol=%s\n", prot_name(protocol));
1205                 printf("Diag: hostandport=%s\n", hostandport ? hostandport : "NULL");
1206                 printf("Diag: path=%s\n", path ? path : "NULL");
1207                 conn = NULL;
1208         } else if (protocol == PROTO_GIT) {
1209                 conn = git_connect_git(fd, hostandport, path, prog, flags);
1210         } else {
1211                 struct strbuf cmd = STRBUF_INIT;
1212                 const char *const *var;
1213
1214                 conn = xmalloc(sizeof(*conn));
1215                 child_process_init(conn);
1216
1217                 if (looks_like_command_line_option(path))
1218                         die("strange pathname '%s' blocked", path);
1219
1220                 strbuf_addstr(&cmd, prog);
1221                 strbuf_addch(&cmd, ' ');
1222                 sq_quote_buf(&cmd, path);
1223
1224                 /* remove repo-local variables from the environment */
1225                 for (var = local_repo_env; *var; var++)
1226                         argv_array_push(&conn->env_array, *var);
1227
1228                 conn->use_shell = 1;
1229                 conn->in = conn->out = -1;
1230                 if (protocol == PROTO_SSH) {
1231                         char *ssh_host = hostandport;
1232                         const char *port = NULL;
1233                         transport_check_allowed("ssh");
1234                         get_host_and_port(&ssh_host, &port);
1235
1236                         if (!port)
1237                                 port = get_port(ssh_host);
1238
1239                         if (flags & CONNECT_DIAG_URL) {
1240                                 printf("Diag: url=%s\n", url ? url : "NULL");
1241                                 printf("Diag: protocol=%s\n", prot_name(protocol));
1242                                 printf("Diag: userandhost=%s\n", ssh_host ? ssh_host : "NULL");
1243                                 printf("Diag: port=%s\n", port ? port : "NONE");
1244                                 printf("Diag: path=%s\n", path ? path : "NULL");
1245
1246                                 free(hostandport);
1247                                 free(path);
1248                                 free(conn);
1249                                 strbuf_release(&cmd);
1250                                 return NULL;
1251                         }
1252                         fill_ssh_args(conn, ssh_host, port, flags);
1253                 } else {
1254                         transport_check_allowed("file");
1255                         if (get_protocol_version_config() > 0) {
1256                                 argv_array_pushf(&conn->env_array, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
1257                                                  get_protocol_version_config());
1258                         }
1259                 }
1260                 argv_array_push(&conn->args, cmd.buf);
1261
1262                 if (start_command(conn))
1263                         die("unable to fork");
1264
1265                 fd[0] = conn->out; /* read from child's stdout */
1266                 fd[1] = conn->in;  /* write to child's stdin */
1267                 strbuf_release(&cmd);
1268         }
1269         free(hostandport);
1270         free(path);
1271         return conn;
1272 }
1273
1274 int finish_connect(struct child_process *conn)
1275 {
1276         int code;
1277         if (!conn || git_connection_is_socket(conn))
1278                 return 0;
1279
1280         code = finish_command(conn);
1281         free(conn);
1282         return code;
1283 }