connect.c

   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 "url.h"
   9
  10 static char *server_capabilities;
  11
  12 static int check_ref(const char *name, int len, unsigned int flags)
  13 {
  14         if (!flags)
  15                 return 1;
  16
  17         if (len < 5 || memcmp(name, "refs/", 5))
  18                 return 0;
  19
  20         /* Skip the "refs/" part */
  21         name += 5;
  22         len -= 5;
  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) && !memcmp(name, "heads/", 6))
  30                 return 1;
  31
  32         /* REF_TAGS means that we want tags */
  33         if ((flags & REF_TAGS) && !memcmp(name, "tags/", 5))
  34                 return 1;
  35
  36         /* All type bits clear means that we are ok with anything */
  37         return !(flags & ~REF_NORMAL);
  38 }
  39
  40 int check_ref_type(const struct ref *ref, int flags)
  41 {
  42         return check_ref(ref->name, strlen(ref->name), flags);
  43 }
  44
  45 static void add_extra_have(struct extra_have_objects *extra, unsigned char *sha1)
  46 {
  47         ALLOC_GROW(extra->array, extra->nr + 1, extra->alloc);
  48         hashcpy(&(extra->array[extra->nr][0]), sha1);
  49         extra->nr++;
  50 }
  51
  52 static void die_initial_contact(int got_at_least_one_head)
  53 {
  54         if (got_at_least_one_head)
  55                 die("The remote end hung up upon initial contact");
  56         else
  57                 die("Could not read from remote repository.\n\n"
  58                     "Please make sure you have the correct access rights\n"
  59                     "and the repository exists.");
  60 }
  61
  62 /*
  63  * Read all the refs from the other end
  64  */
  65 struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
  66                               struct ref **list, unsigned int flags,
  67                               struct extra_have_objects *extra_have)
  68 {
  69         int got_at_least_one_head = 0;
  70
  71         *list = NULL;
  72         for (;;) {
  73                 struct ref *ref;
  74                 unsigned char old_sha1[20];
  75                 char *name;
  76                 int len, name_len;
  77                 char *buffer = packet_buffer;
  78
  79                 len = packet_read(in, &src_buf, &src_len,
  80                                   packet_buffer, sizeof(packet_buffer),
  81                                   PACKET_READ_GENTLE_ON_EOF |
  82                                   PACKET_READ_CHOMP_NEWLINE);
  83                 if (len < 0)
  84                         die_initial_contact(got_at_least_one_head);
  85
  86                 if (!len)
  87                         break;
  88
  89                 if (len > 4 && !prefixcmp(buffer, "ERR "))
  90                         die("remote error: %s", buffer + 4);
  91
  92                 if (len < 42 || get_sha1_hex(buffer, old_sha1) || buffer[40] != ' ')
  93                         die("protocol error: expected sha/ref, got '%s'", buffer);
  94                 name = buffer + 41;
  95
  96                 name_len = strlen(name);
  97                 if (len != name_len + 41) {
  98                         free(server_capabilities);
  99                         server_capabilities = xstrdup(name + name_len + 1);
 100                 }
 101
 102                 if (extra_have &&
 103                     name_len == 5 && !memcmp(".have", name, 5)) {
 104                         add_extra_have(extra_have, old_sha1);
 105                         continue;
 106                 }
 107
 108                 if (!check_ref(name, name_len, flags))
 109                         continue;
 110                 ref = alloc_ref(buffer + 41);
 111                 hashcpy(ref->old_sha1, old_sha1);
 112                 *list = ref;
 113                 list = &ref->next;
 114                 got_at_least_one_head = 1;
 115         }
 116         return list;
 117 }
 118
 119 const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
 120 {
 121         int len;
 122
 123         if (!feature_list)
 124                 return NULL;
 125
 126         len = strlen(feature);
 127         while (*feature_list) {
 128                 const char *found = strstr(feature_list, feature);
 129                 if (!found)
 130                         return NULL;
 131                 if (feature_list == found || isspace(found[-1])) {
 132                         const char *value = found + len;
 133                         /* feature with no value (e.g., "thin-pack") */
 134                         if (!*value || isspace(*value)) {
 135                                 if (lenp)
 136                                         *lenp = 0;
 137                                 return value;
 138                         }
 139                         /* feature with a value (e.g., "agent=git/1.2.3") */
 140                         else if (*value == '=') {
 141                                 value++;
 142                                 if (lenp)
 143                                         *lenp = strcspn(value, " \t\n");
 144                                 return value;
 145                         }
 146                         /*
 147                          * otherwise we matched a substring of another feature;
 148                          * keep looking
 149                          */
 150                 }
 151                 feature_list = found + 1;
 152         }
 153         return NULL;
 154 }
 155
 156 int parse_feature_request(const char *feature_list, const char *feature)
 157 {
 158         return !!parse_feature_value(feature_list, feature, NULL);
 159 }
 160
 161 const char *server_feature_value(const char *feature, int *len)
 162 {
 163         return parse_feature_value(server_capabilities, feature, len);
 164 }
 165
 166 int server_supports(const char *feature)
 167 {
 168         return !!server_feature_value(feature, NULL);
 169 }
 170
 171 enum protocol {
 172         PROTO_LOCAL = 1,
 173         PROTO_SSH,
 174         PROTO_GIT
 175 };
 176
 177 static enum protocol get_protocol(const char *name)
 178 {
 179         if (!strcmp(name, "ssh"))
 180                 return PROTO_SSH;
 181         if (!strcmp(name, "git"))
 182                 return PROTO_GIT;
 183         if (!strcmp(name, "git+ssh"))
 184                 return PROTO_SSH;
 185         if (!strcmp(name, "ssh+git"))
 186                 return PROTO_SSH;
 187         if (!strcmp(name, "file"))
 188                 return PROTO_LOCAL;
 189         die("I don't handle protocol '%s'", name);
 190 }
 191
 192 #define STR_(s) # s
 193 #define STR(s)  STR_(s)
 194
 195 static void get_host_and_port(char **host, const char **port)
 196 {
 197         char *colon, *end;
 198
 199         if (*host[0] == '[') {
 200                 end = strchr(*host + 1, ']');
 201                 if (end) {
 202                         *end = 0;
 203                         end++;
 204                         (*host)++;
 205                 } else
 206                         end = *host;
 207         } else
 208                 end = *host;
 209         colon = strchr(end, ':');
 210
 211         if (colon) {
 212                 *colon = 0;
 213                 *port = colon + 1;
 214         }
 215 }
 216
 217 static void enable_keepalive(int sockfd)
 218 {
 219         int ka = 1;
 220
 221         if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
 222                 fprintf(stderr, "unable to set SO_KEEPALIVE on socket: %s\n",
 223                         strerror(errno));
 224 }
 225
 226 #ifndef NO_IPV6
 227
 228 static const char *ai_name(const struct addrinfo *ai)
 229 {
 230         static char addr[NI_MAXHOST];
 231         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
 232                         NI_NUMERICHOST) != 0)
 233                 strcpy(addr, "(unknown)");
 234
 235         return addr;
 236 }
 237
 238 /*
 239  * Returns a connected socket() fd, or else die()s.
 240  */
 241 static int git_tcp_connect_sock(char *host, int flags)
 242 {
 243         struct strbuf error_message = STRBUF_INIT;
 244         int sockfd = -1;
 245         const char *port = STR(DEFAULT_GIT_PORT);
 246         struct addrinfo hints, *ai0, *ai;
 247         int gai;
 248         int cnt = 0;
 249
 250         get_host_and_port(&host, &port);
 251         if (!*port)
 252                 port = "<none>";
 253
 254         memset(&hints, 0, sizeof(hints));
 255         hints.ai_socktype = SOCK_STREAM;
 256         hints.ai_protocol = IPPROTO_TCP;
 257
 258         if (flags & CONNECT_VERBOSE)
 259                 fprintf(stderr, "Looking up %s ... ", host);
 260
 261         gai = getaddrinfo(host, port, &hints, &ai);
 262         if (gai)
 263                 die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
 264
 265         if (flags & CONNECT_VERBOSE)
 266                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 267
 268         for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
 269                 sockfd = socket(ai->ai_family,
 270                                 ai->ai_socktype, ai->ai_protocol);
 271                 if ((sockfd < 0) ||
 272                     (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
 273                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 274                                     host, cnt, ai_name(ai), strerror(errno));
 275                         if (0 <= sockfd)
 276                                 close(sockfd);
 277                         sockfd = -1;
 278                         continue;
 279                 }
 280                 if (flags & CONNECT_VERBOSE)
 281                         fprintf(stderr, "%s ", ai_name(ai));
 282                 break;
 283         }
 284
 285         freeaddrinfo(ai0);
 286
 287         if (sockfd < 0)
 288                 die("unable to connect to %s:\n%s", host, error_message.buf);
 289
 290         enable_keepalive(sockfd);
 291
 292         if (flags & CONNECT_VERBOSE)
 293                 fprintf(stderr, "done.\n");
 294
 295         strbuf_release(&error_message);
 296
 297         return sockfd;
 298 }
 299
 300 #else /* NO_IPV6 */
 301
 302 /*
 303  * Returns a connected socket() fd, or else die()s.
 304  */
 305 static int git_tcp_connect_sock(char *host, int flags)
 306 {
 307         struct strbuf error_message = STRBUF_INIT;
 308         int sockfd = -1;
 309         const char *port = STR(DEFAULT_GIT_PORT);
 310         char *ep;
 311         struct hostent *he;
 312         struct sockaddr_in sa;
 313         char **ap;
 314         unsigned int nport;
 315         int cnt;
 316
 317         get_host_and_port(&host, &port);
 318
 319         if (flags & CONNECT_VERBOSE)
 320                 fprintf(stderr, "Looking up %s ... ", host);
 321
 322         he = gethostbyname(host);
 323         if (!he)
 324                 die("Unable to look up %s (%s)", host, hstrerror(h_errno));
 325         nport = strtoul(port, &ep, 10);
 326         if ( ep == port || *ep ) {
 327                 /* Not numeric */
 328                 struct servent *se = getservbyname(port,"tcp");
 329                 if ( !se )
 330                         die("Unknown port %s", port);
 331                 nport = se->s_port;
 332         }
 333
 334         if (flags & CONNECT_VERBOSE)
 335                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 336
 337         for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
 338                 memset(&sa, 0, sizeof sa);
 339                 sa.sin_family = he->h_addrtype;
 340                 sa.sin_port = htons(nport);
 341                 memcpy(&sa.sin_addr, *ap, he->h_length);
 342
 343                 sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 344                 if ((sockfd < 0) ||
 345                     connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 346                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 347                                 host,
 348                                 cnt,
 349                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr),
 350                                 strerror(errno));
 351                         if (0 <= sockfd)
 352                                 close(sockfd);
 353                         sockfd = -1;
 354                         continue;
 355                 }
 356                 if (flags & CONNECT_VERBOSE)
 357                         fprintf(stderr, "%s ",
 358                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr));
 359                 break;
 360         }
 361
 362         if (sockfd < 0)
 363                 die("unable to connect to %s:\n%s", host, error_message.buf);
 364
 365         enable_keepalive(sockfd);
 366
 367         if (flags & CONNECT_VERBOSE)
 368                 fprintf(stderr, "done.\n");
 369
 370         return sockfd;
 371 }
 372
 373 #endif /* NO_IPV6 */
 374
 375
 376 static void git_tcp_connect(int fd[2], char *host, int flags)
 377 {
 378         int sockfd = git_tcp_connect_sock(host, flags);
 379
 380         fd[0] = sockfd;
 381         fd[1] = dup(sockfd);
 382 }
 383
 384
 385 static char *git_proxy_command;
 386
 387 static int git_proxy_command_options(const char *var, const char *value,
 388                 void *cb)
 389 {
 390         if (!strcmp(var, "core.gitproxy")) {
 391                 const char *for_pos;
 392                 int matchlen = -1;
 393                 int hostlen;
 394                 const char *rhost_name = cb;
 395                 int rhost_len = strlen(rhost_name);
 396
 397                 if (git_proxy_command)
 398                         return 0;
 399                 if (!value)
 400                         return config_error_nonbool(var);
 401                 /* [core]
 402                  * ;# matches www.kernel.org as well
 403                  * gitproxy = netcatter-1 for kernel.org
 404                  * gitproxy = netcatter-2 for sample.xz
 405                  * gitproxy = netcatter-default
 406                  */
 407                 for_pos = strstr(value, " for ");
 408                 if (!for_pos)
 409                         /* matches everybody */
 410                         matchlen = strlen(value);
 411                 else {
 412                         hostlen = strlen(for_pos + 5);
 413                         if (rhost_len < hostlen)
 414                                 matchlen = -1;
 415                         else if (!strncmp(for_pos + 5,
 416                                           rhost_name + rhost_len - hostlen,
 417                                           hostlen) &&
 418                                  ((rhost_len == hostlen) ||
 419                                   rhost_name[rhost_len - hostlen -1] == '.'))
 420                                 matchlen = for_pos - value;
 421                         else
 422                                 matchlen = -1;
 423                 }
 424                 if (0 <= matchlen) {
 425                         /* core.gitproxy = none for kernel.org */
 426                         if (matchlen == 4 &&
 427                             !memcmp(value, "none", 4))
 428                                 matchlen = 0;
 429                         git_proxy_command = xmemdupz(value, matchlen);
 430                 }
 431                 return 0;
 432         }
 433
 434         return git_default_config(var, value, cb);
 435 }
 436
 437 static int git_use_proxy(const char *host)
 438 {
 439         git_proxy_command = getenv("GIT_PROXY_COMMAND");
 440         git_config(git_proxy_command_options, (void*)host);
 441         return (git_proxy_command && *git_proxy_command);
 442 }
 443
 444 static struct child_process *git_proxy_connect(int fd[2], char *host)
 445 {
 446         const char *port = STR(DEFAULT_GIT_PORT);
 447         const char **argv;
 448         struct child_process *proxy;
 449
 450         get_host_and_port(&host, &port);
 451
 452         argv = xmalloc(sizeof(*argv) * 4);
 453         argv[0] = git_proxy_command;
 454         argv[1] = host;
 455         argv[2] = port;
 456         argv[3] = NULL;
 457         proxy = xcalloc(1, sizeof(*proxy));
 458         proxy->argv = argv;
 459         proxy->in = -1;
 460         proxy->out = -1;
 461         if (start_command(proxy))
 462                 die("cannot start proxy %s", argv[0]);
 463         fd[0] = proxy->out; /* read from proxy stdout */
 464         fd[1] = proxy->in;  /* write to proxy stdin */
 465         return proxy;
 466 }
 467
 468 #define MAX_CMD_LEN 1024
 469
 470 static char *get_port(char *host)
 471 {
 472         char *end;
 473         char *p = strchr(host, ':');
 474
 475         if (p) {
 476                 long port = strtol(p + 1, &end, 10);
 477                 if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
 478                         *p = '\0';
 479                         return p+1;
 480                 }
 481         }
 482
 483         return NULL;
 484 }
 485
 486 static struct child_process no_fork;
 487
 488 /*
 489  * This returns a dummy child_process if the transport protocol does not
 490  * need fork(2), or a struct child_process object if it does.  Once done,
 491  * finish the connection with finish_connect() with the value returned from
 492  * this function (it is safe to call finish_connect() with NULL to support
 493  * the former case).
 494  *
 495  * If it returns, the connect is successful; it just dies on errors (this
 496  * will hopefully be changed in a libification effort, to return NULL when
 497  * the connection failed).
 498  */
 499 struct child_process *git_connect(int fd[2], const char *url_orig,
 500                                   const char *prog, int flags)
 501 {
 502         char *url;
 503         char *host, *path;
 504         char *end;
 505         int c;
 506         struct child_process *conn = &no_fork;
 507         enum protocol protocol = PROTO_LOCAL;
 508         int free_path = 0;
 509         char *port = NULL;
 510         const char **arg;
 511         struct strbuf cmd;
 512
 513         /* Without this we cannot rely on waitpid() to tell
 514          * what happened to our children.
 515          */
 516         signal(SIGCHLD, SIG_DFL);
 517
 518         if (is_url(url_orig))
 519                 url = url_decode(url_orig);
 520         else
 521                 url = xstrdup(url_orig);
 522
 523         host = strstr(url, "://");
 524         if (host) {
 525                 *host = '\0';
 526                 protocol = get_protocol(url);
 527                 host += 3;
 528                 c = '/';
 529         } else {
 530                 host = url;
 531                 c = ':';
 532         }
 533
 534         /*
 535          * Don't do destructive transforms with git:// as that
 536          * protocol code does '[]' unwrapping of its own.
 537          */
 538         if (host[0] == '[') {
 539                 end = strchr(host + 1, ']');
 540                 if (end) {
 541                         if (protocol != PROTO_GIT) {
 542                                 *end = 0;
 543                                 host++;
 544                         }
 545                         end++;
 546                 } else
 547                         end = host;
 548         } else
 549                 end = host;
 550
 551         path = strchr(end, c);
 552         if (path && !has_dos_drive_prefix(end)) {
 553                 if (c == ':') {
 554                         if (path < strchrnul(host, '/')) {
 555                                 protocol = PROTO_SSH;
 556                                 *path++ = '\0';
 557                         } else /* '/' in the host part, assume local path */
 558                                 path = end;
 559                 }
 560         } else
 561                 path = end;
 562
 563         if (!path || !*path)
 564                 die("No path specified. See 'man git-pull' for valid url syntax");
 565
 566         /*
 567          * null-terminate hostname and point path to ~ for URL's like this:
 568          *    ssh://host.xz/~user/repo
 569          */
 570         if (protocol != PROTO_LOCAL && host != url) {
 571                 char *ptr = path;
 572                 if (path[1] == '~')
 573                         path++;
 574                 else {
 575                         path = xstrdup(ptr);
 576                         free_path = 1;
 577                 }
 578
 579                 *ptr = '\0';
 580         }
 581
 582         /*
 583          * Add support for ssh port: ssh://host.xy:<port>/...
 584          */
 585         if (protocol == PROTO_SSH && host != url)
 586                 port = get_port(end);
 587
 588         if (protocol == PROTO_GIT) {
 589                 /* These underlying connection commands die() if they
 590                  * cannot connect.
 591                  */
 592                 char *target_host = xstrdup(host);
 593                 if (git_use_proxy(host))
 594                         conn = git_proxy_connect(fd, host);
 595                 else
 596                         git_tcp_connect(fd, host, flags);
 597                 /*
 598                  * Separate original protocol components prog and path
 599                  * from extended host header with a NUL byte.
 600                  *
 601                  * Note: Do not add any other headers here!  Doing so
 602                  * will cause older git-daemon servers to crash.
 603                  */
 604                 packet_write(fd[1],
 605                              "%s %s%chost=%s%c",
 606                              prog, path, 0,
 607                              target_host, 0);
 608                 free(target_host);
 609                 free(url);
 610                 if (free_path)
 611                         free(path);
 612                 return conn;
 613         }
 614
 615         conn = xcalloc(1, sizeof(*conn));
 616
 617         strbuf_init(&cmd, MAX_CMD_LEN);
 618         strbuf_addstr(&cmd, prog);
 619         strbuf_addch(&cmd, ' ');
 620         sq_quote_buf(&cmd, path);
 621         if (cmd.len >= MAX_CMD_LEN)
 622                 die("command line too long");
 623
 624         conn->in = conn->out = -1;
 625         conn->argv = arg = xcalloc(7, sizeof(*arg));
 626         if (protocol == PROTO_SSH) {
 627                 const char *ssh = getenv("GIT_SSH");
 628                 int putty = ssh && strcasestr(ssh, "plink");
 629                 if (!ssh) ssh = "ssh";
 630
 631                 *arg++ = ssh;
 632                 if (putty && !strcasestr(ssh, "tortoiseplink"))
 633                         *arg++ = "-batch";
 634                 if (port) {
 635                         /* P is for PuTTY, p is for OpenSSH */
 636                         *arg++ = putty ? "-P" : "-p";
 637                         *arg++ = port;
 638                 }
 639                 *arg++ = host;
 640         }
 641         else {
 642                 /* remove repo-local variables from the environment */
 643                 conn->env = local_repo_env;
 644                 conn->use_shell = 1;
 645         }
 646         *arg++ = cmd.buf;
 647         *arg = NULL;
 648
 649         if (start_command(conn))
 650                 die("unable to fork");
 651
 652         fd[0] = conn->out; /* read from child's stdout */
 653         fd[1] = conn->in;  /* write to child's stdin */
 654         strbuf_release(&cmd);
 655         free(url);
 656         if (free_path)
 657                 free(path);
 658         return conn;
 659 }
 660
 661 int git_connection_is_socket(struct child_process *conn)
 662 {
 663         return conn == &no_fork;
 664 }
 665
 666 int finish_connect(struct child_process *conn)
 667 {
 668         int code;
 669         if (!conn || git_connection_is_socket(conn))
 670                 return 0;
 671
 672         code = finish_command(conn);
 673         free(conn->argv);
 674         free(conn);
 675         return code;
 676 }