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 "connect.h"
   9 #include "url.h"
  10
  11 static char *server_capabilities;
  12
  13 static int check_ref(const char *name, int len, unsigned int flags)
  14 {
  15         if (!flags)
  16                 return 1;
  17
  18         if (len < 5 || memcmp(name, "refs/", 5))
  19                 return 0;
  20
  21         /* Skip the "refs/" part */
  22         name += 5;
  23         len -= 5;
  24
  25         /* REF_NORMAL means that we don't want the magic fake tag refs */
  26         if ((flags & REF_NORMAL) && check_refname_format(name, 0))
  27                 return 0;
  28
  29         /* REF_HEADS means that we want regular branch heads */
  30         if ((flags & REF_HEADS) && !memcmp(name, "heads/", 6))
  31                 return 1;
  32
  33         /* REF_TAGS means that we want tags */
  34         if ((flags & REF_TAGS) && !memcmp(name, "tags/", 5))
  35                 return 1;
  36
  37         /* All type bits clear means that we are ok with anything */
  38         return !(flags & ~REF_NORMAL);
  39 }
  40
  41 int check_ref_type(const struct ref *ref, int flags)
  42 {
  43         return check_ref(ref->name, strlen(ref->name), flags);
  44 }
  45
  46 static void add_extra_have(struct extra_have_objects *extra, unsigned char *sha1)
  47 {
  48         ALLOC_GROW(extra->array, extra->nr + 1, extra->alloc);
  49         hashcpy(&(extra->array[extra->nr][0]), sha1);
  50         extra->nr++;
  51 }
  52
  53 static void die_initial_contact(int got_at_least_one_head)
  54 {
  55         if (got_at_least_one_head)
  56                 die("The remote end hung up upon initial contact");
  57         else
  58                 die("Could not read from remote repository.\n\n"
  59                     "Please make sure you have the correct access rights\n"
  60                     "and the repository exists.");
  61 }
  62
  63 /*
  64  * Read all the refs from the other end
  65  */
  66 struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
  67                               struct ref **list, unsigned int flags,
  68                               struct extra_have_objects *extra_have)
  69 {
  70         int got_at_least_one_head = 0;
  71
  72         *list = NULL;
  73         for (;;) {
  74                 struct ref *ref;
  75                 unsigned char old_sha1[20];
  76                 char *name;
  77                 int len, name_len;
  78                 char *buffer = packet_buffer;
  79
  80                 len = packet_read(in, &src_buf, &src_len,
  81                                   packet_buffer, sizeof(packet_buffer),
  82                                   PACKET_READ_GENTLE_ON_EOF |
  83                                   PACKET_READ_CHOMP_NEWLINE);
  84                 if (len < 0)
  85                         die_initial_contact(got_at_least_one_head);
  86
  87                 if (!len)
  88                         break;
  89
  90                 if (len > 4 && !prefixcmp(buffer, "ERR "))
  91                         die("remote error: %s", buffer + 4);
  92
  93                 if (len < 42 || get_sha1_hex(buffer, old_sha1) || buffer[40] != ' ')
  94                         die("protocol error: expected sha/ref, got '%s'", buffer);
  95                 name = buffer + 41;
  96
  97                 name_len = strlen(name);
  98                 if (len != name_len + 41) {
  99                         free(server_capabilities);
 100                         server_capabilities = xstrdup(name + name_len + 1);
 101                 }
 102
 103                 if (extra_have &&
 104                     name_len == 5 && !memcmp(".have", name, 5)) {
 105                         add_extra_have(extra_have, old_sha1);
 106                         continue;
 107                 }
 108
 109                 if (!check_ref(name, name_len, flags))
 110                         continue;
 111                 ref = alloc_ref(buffer + 41);
 112                 hashcpy(ref->old_sha1, old_sha1);
 113                 *list = ref;
 114                 list = &ref->next;
 115                 got_at_least_one_head = 1;
 116         }
 117         return list;
 118 }
 119
 120 const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
 121 {
 122         int len;
 123
 124         if (!feature_list)
 125                 return NULL;
 126
 127         len = strlen(feature);
 128         while (*feature_list) {
 129                 const char *found = strstr(feature_list, feature);
 130                 if (!found)
 131                         return NULL;
 132                 if (feature_list == found || isspace(found[-1])) {
 133                         const char *value = found + len;
 134                         /* feature with no value (e.g., "thin-pack") */
 135                         if (!*value || isspace(*value)) {
 136                                 if (lenp)
 137                                         *lenp = 0;
 138                                 return value;
 139                         }
 140                         /* feature with a value (e.g., "agent=git/1.2.3") */
 141                         else if (*value == '=') {
 142                                 value++;
 143                                 if (lenp)
 144                                         *lenp = strcspn(value, " \t\n");
 145                                 return value;
 146                         }
 147                         /*
 148                          * otherwise we matched a substring of another feature;
 149                          * keep looking
 150                          */
 151                 }
 152                 feature_list = found + 1;
 153         }
 154         return NULL;
 155 }
 156
 157 int parse_feature_request(const char *feature_list, const char *feature)
 158 {
 159         return !!parse_feature_value(feature_list, feature, NULL);
 160 }
 161
 162 const char *server_feature_value(const char *feature, int *len)
 163 {
 164         return parse_feature_value(server_capabilities, feature, len);
 165 }
 166
 167 int server_supports(const char *feature)
 168 {
 169         return !!server_feature_value(feature, NULL);
 170 }
 171
 172 enum protocol {
 173         PROTO_LOCAL = 1,
 174         PROTO_SSH,
 175         PROTO_GIT
 176 };
 177
 178 static enum protocol get_protocol(const char *name)
 179 {
 180         if (!strcmp(name, "ssh"))
 181                 return PROTO_SSH;
 182         if (!strcmp(name, "git"))
 183                 return PROTO_GIT;
 184         if (!strcmp(name, "git+ssh"))
 185                 return PROTO_SSH;
 186         if (!strcmp(name, "ssh+git"))
 187                 return PROTO_SSH;
 188         if (!strcmp(name, "file"))
 189                 return PROTO_LOCAL;
 190         die("I don't handle protocol '%s'", name);
 191 }
 192
 193 #define STR_(s) # s
 194 #define STR(s)  STR_(s)
 195
 196 static void get_host_and_port(char **host, const char **port)
 197 {
 198         char *colon, *end;
 199
 200         if (*host[0] == '[') {
 201                 end = strchr(*host + 1, ']');
 202                 if (end) {
 203                         *end = 0;
 204                         end++;
 205                         (*host)++;
 206                 } else
 207                         end = *host;
 208         } else
 209                 end = *host;
 210         colon = strchr(end, ':');
 211
 212         if (colon) {
 213                 *colon = 0;
 214                 *port = colon + 1;
 215         }
 216 }
 217
 218 static void enable_keepalive(int sockfd)
 219 {
 220         int ka = 1;
 221
 222         if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
 223                 fprintf(stderr, "unable to set SO_KEEPALIVE on socket: %s\n",
 224                         strerror(errno));
 225 }
 226
 227 #ifndef NO_IPV6
 228
 229 static const char *ai_name(const struct addrinfo *ai)
 230 {
 231         static char addr[NI_MAXHOST];
 232         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
 233                         NI_NUMERICHOST) != 0)
 234                 strcpy(addr, "(unknown)");
 235
 236         return addr;
 237 }
 238
 239 /*
 240  * Returns a connected socket() fd, or else die()s.
 241  */
 242 static int git_tcp_connect_sock(char *host, int flags)
 243 {
 244         struct strbuf error_message = STRBUF_INIT;
 245         int sockfd = -1;
 246         const char *port = STR(DEFAULT_GIT_PORT);
 247         struct addrinfo hints, *ai0, *ai;
 248         int gai;
 249         int cnt = 0;
 250
 251         get_host_and_port(&host, &port);
 252         if (!*port)
 253                 port = "<none>";
 254
 255         memset(&hints, 0, sizeof(hints));
 256         hints.ai_socktype = SOCK_STREAM;
 257         hints.ai_protocol = IPPROTO_TCP;
 258
 259         if (flags & CONNECT_VERBOSE)
 260                 fprintf(stderr, "Looking up %s ... ", host);
 261
 262         gai = getaddrinfo(host, port, &hints, &ai);
 263         if (gai)
 264                 die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
 265
 266         if (flags & CONNECT_VERBOSE)
 267                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 268
 269         for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
 270                 sockfd = socket(ai->ai_family,
 271                                 ai->ai_socktype, ai->ai_protocol);
 272                 if ((sockfd < 0) ||
 273                     (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
 274                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 275                                     host, cnt, ai_name(ai), strerror(errno));
 276                         if (0 <= sockfd)
 277                                 close(sockfd);
 278                         sockfd = -1;
 279                         continue;
 280                 }
 281                 if (flags & CONNECT_VERBOSE)
 282                         fprintf(stderr, "%s ", ai_name(ai));
 283                 break;
 284         }
 285
 286         freeaddrinfo(ai0);
 287
 288         if (sockfd < 0)
 289                 die("unable to connect to %s:\n%s", host, error_message.buf);
 290
 291         enable_keepalive(sockfd);
 292
 293         if (flags & CONNECT_VERBOSE)
 294                 fprintf(stderr, "done.\n");
 295
 296         strbuf_release(&error_message);
 297
 298         return sockfd;
 299 }
 300
 301 #else /* NO_IPV6 */
 302
 303 /*
 304  * Returns a connected socket() fd, or else die()s.
 305  */
 306 static int git_tcp_connect_sock(char *host, int flags)
 307 {
 308         struct strbuf error_message = STRBUF_INIT;
 309         int sockfd = -1;
 310         const char *port = STR(DEFAULT_GIT_PORT);
 311         char *ep;
 312         struct hostent *he;
 313         struct sockaddr_in sa;
 314         char **ap;
 315         unsigned int nport;
 316         int cnt;
 317
 318         get_host_and_port(&host, &port);
 319
 320         if (flags & CONNECT_VERBOSE)
 321                 fprintf(stderr, "Looking up %s ... ", host);
 322
 323         he = gethostbyname(host);
 324         if (!he)
 325                 die("Unable to look up %s (%s)", host, hstrerror(h_errno));
 326         nport = strtoul(port, &ep, 10);
 327         if ( ep == port || *ep ) {
 328                 /* Not numeric */
 329                 struct servent *se = getservbyname(port,"tcp");
 330                 if ( !se )
 331                         die("Unknown port %s", port);
 332                 nport = se->s_port;
 333         }
 334
 335         if (flags & CONNECT_VERBOSE)
 336                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 337
 338         for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
 339                 memset(&sa, 0, sizeof sa);
 340                 sa.sin_family = he->h_addrtype;
 341                 sa.sin_port = htons(nport);
 342                 memcpy(&sa.sin_addr, *ap, he->h_length);
 343
 344                 sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 345                 if ((sockfd < 0) ||
 346                     connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 347                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 348                                 host,
 349                                 cnt,
 350                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr),
 351                                 strerror(errno));
 352                         if (0 <= sockfd)
 353                                 close(sockfd);
 354                         sockfd = -1;
 355                         continue;
 356                 }
 357                 if (flags & CONNECT_VERBOSE)
 358                         fprintf(stderr, "%s ",
 359                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr));
 360                 break;
 361         }
 362
 363         if (sockfd < 0)
 364                 die("unable to connect to %s:\n%s", host, error_message.buf);
 365
 366         enable_keepalive(sockfd);
 367
 368         if (flags & CONNECT_VERBOSE)
 369                 fprintf(stderr, "done.\n");
 370
 371         return sockfd;
 372 }
 373
 374 #endif /* NO_IPV6 */
 375
 376
 377 static void git_tcp_connect(int fd[2], char *host, int flags)
 378 {
 379         int sockfd = git_tcp_connect_sock(host, flags);
 380
 381         fd[0] = sockfd;
 382         fd[1] = dup(sockfd);
 383 }
 384
 385
 386 static char *git_proxy_command;
 387
 388 static int git_proxy_command_options(const char *var, const char *value,
 389                 void *cb)
 390 {
 391         if (!strcmp(var, "core.gitproxy")) {
 392                 const char *for_pos;
 393                 int matchlen = -1;
 394                 int hostlen;
 395                 const char *rhost_name = cb;
 396                 int rhost_len = strlen(rhost_name);
 397
 398                 if (git_proxy_command)
 399                         return 0;
 400                 if (!value)
 401                         return config_error_nonbool(var);
 402                 /* [core]
 403                  * ;# matches www.kernel.org as well
 404                  * gitproxy = netcatter-1 for kernel.org
 405                  * gitproxy = netcatter-2 for sample.xz
 406                  * gitproxy = netcatter-default
 407                  */
 408                 for_pos = strstr(value, " for ");
 409                 if (!for_pos)
 410                         /* matches everybody */
 411                         matchlen = strlen(value);
 412                 else {
 413                         hostlen = strlen(for_pos + 5);
 414                         if (rhost_len < hostlen)
 415                                 matchlen = -1;
 416                         else if (!strncmp(for_pos + 5,
 417                                           rhost_name + rhost_len - hostlen,
 418                                           hostlen) &&
 419                                  ((rhost_len == hostlen) ||
 420                                   rhost_name[rhost_len - hostlen -1] == '.'))
 421                                 matchlen = for_pos - value;
 422                         else
 423                                 matchlen = -1;
 424                 }
 425                 if (0 <= matchlen) {
 426                         /* core.gitproxy = none for kernel.org */
 427                         if (matchlen == 4 &&
 428                             !memcmp(value, "none", 4))
 429                                 matchlen = 0;
 430                         git_proxy_command = xmemdupz(value, matchlen);
 431                 }
 432                 return 0;
 433         }
 434
 435         return git_default_config(var, value, cb);
 436 }
 437
 438 static int git_use_proxy(const char *host)
 439 {
 440         git_proxy_command = getenv("GIT_PROXY_COMMAND");
 441         git_config(git_proxy_command_options, (void*)host);
 442         return (git_proxy_command && *git_proxy_command);
 443 }
 444
 445 static struct child_process *git_proxy_connect(int fd[2], char *host)
 446 {
 447         const char *port = STR(DEFAULT_GIT_PORT);
 448         const char **argv;
 449         struct child_process *proxy;
 450
 451         get_host_and_port(&host, &port);
 452
 453         argv = xmalloc(sizeof(*argv) * 4);
 454         argv[0] = git_proxy_command;
 455         argv[1] = host;
 456         argv[2] = port;
 457         argv[3] = NULL;
 458         proxy = xcalloc(1, sizeof(*proxy));
 459         proxy->argv = argv;
 460         proxy->in = -1;
 461         proxy->out = -1;
 462         if (start_command(proxy))
 463                 die("cannot start proxy %s", argv[0]);
 464         fd[0] = proxy->out; /* read from proxy stdout */
 465         fd[1] = proxy->in;  /* write to proxy stdin */
 466         return proxy;
 467 }
 468
 469 #define MAX_CMD_LEN 1024
 470
 471 static char *get_port(char *host)
 472 {
 473         char *end;
 474         char *p = strchr(host, ':');
 475
 476         if (p) {
 477                 long port = strtol(p + 1, &end, 10);
 478                 if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
 479                         *p = '\0';
 480                         return p+1;
 481                 }
 482         }
 483
 484         return NULL;
 485 }
 486
 487 static struct child_process no_fork;
 488
 489 /*
 490  * This returns a dummy child_process if the transport protocol does not
 491  * need fork(2), or a struct child_process object if it does.  Once done,
 492  * finish the connection with finish_connect() with the value returned from
 493  * this function (it is safe to call finish_connect() with NULL to support
 494  * the former case).
 495  *
 496  * If it returns, the connect is successful; it just dies on errors (this
 497  * will hopefully be changed in a libification effort, to return NULL when
 498  * the connection failed).
 499  */
 500 struct child_process *git_connect(int fd[2], const char *url_orig,
 501                                   const char *prog, int flags)
 502 {
 503         char *url;
 504         char *host, *path;
 505         char *end;
 506         int c;
 507         struct child_process *conn = &no_fork;
 508         enum protocol protocol = PROTO_LOCAL;
 509         int free_path = 0;
 510         char *port = NULL;
 511         const char **arg;
 512         struct strbuf cmd;
 513
 514         /* Without this we cannot rely on waitpid() to tell
 515          * what happened to our children.
 516          */
 517         signal(SIGCHLD, SIG_DFL);
 518
 519         if (is_url(url_orig))
 520                 url = url_decode(url_orig);
 521         else
 522                 url = xstrdup(url_orig);
 523
 524         host = strstr(url, "://");
 525         if (host) {
 526                 *host = '\0';
 527                 protocol = get_protocol(url);
 528                 host += 3;
 529                 c = '/';
 530         } else {
 531                 host = url;
 532                 c = ':';
 533         }
 534
 535         /*
 536          * Don't do destructive transforms with git:// as that
 537          * protocol code does '[]' unwrapping of its own.
 538          */
 539         if (host[0] == '[') {
 540                 end = strchr(host + 1, ']');
 541                 if (end) {
 542                         if (protocol != PROTO_GIT) {
 543                                 *end = 0;
 544                                 host++;
 545                         }
 546                         end++;
 547                 } else
 548                         end = host;
 549         } else
 550                 end = host;
 551
 552         path = strchr(end, c);
 553         if (path && !has_dos_drive_prefix(end)) {
 554                 if (c == ':') {
 555                         if (host != url || path < strchrnul(host, '/')) {
 556                                 protocol = PROTO_SSH;
 557                                 *path++ = '\0';
 558                         } else /* '/' in the host part, assume local path */
 559                                 path = end;
 560                 }
 561         } else
 562                 path = end;
 563
 564         if (!path || !*path)
 565                 die("No path specified. See 'man git-pull' for valid url syntax");
 566
 567         /*
 568          * null-terminate hostname and point path to ~ for URL's like this:
 569          *    ssh://host.xz/~user/repo
 570          */
 571         if (protocol != PROTO_LOCAL && host != url) {
 572                 char *ptr = path;
 573                 if (path[1] == '~')
 574                         path++;
 575                 else {
 576                         path = xstrdup(ptr);
 577                         free_path = 1;
 578                 }
 579
 580                 *ptr = '\0';
 581         }
 582
 583         /*
 584          * Add support for ssh port: ssh://host.xy:<port>/...
 585          */
 586         if (protocol == PROTO_SSH && host != url)
 587                 port = get_port(end);
 588
 589         if (protocol == PROTO_GIT) {
 590                 /* These underlying connection commands die() if they
 591                  * cannot connect.
 592                  */
 593                 char *target_host = xstrdup(host);
 594                 if (git_use_proxy(host))
 595                         conn = git_proxy_connect(fd, host);
 596                 else
 597                         git_tcp_connect(fd, host, flags);
 598                 /*
 599                  * Separate original protocol components prog and path
 600                  * from extended host header with a NUL byte.
 601                  *
 602                  * Note: Do not add any other headers here!  Doing so
 603                  * will cause older git-daemon servers to crash.
 604                  */
 605                 packet_write(fd[1],
 606                              "%s %s%chost=%s%c",
 607                              prog, path, 0,
 608                              target_host, 0);
 609                 free(target_host);
 610                 free(url);
 611                 if (free_path)
 612                         free(path);
 613                 return conn;
 614         }
 615
 616         conn = xcalloc(1, sizeof(*conn));
 617
 618         strbuf_init(&cmd, MAX_CMD_LEN);
 619         strbuf_addstr(&cmd, prog);
 620         strbuf_addch(&cmd, ' ');
 621         sq_quote_buf(&cmd, path);
 622         if (cmd.len >= MAX_CMD_LEN)
 623                 die("command line too long");
 624
 625         conn->in = conn->out = -1;
 626         conn->argv = arg = xcalloc(7, sizeof(*arg));
 627         if (protocol == PROTO_SSH) {
 628                 const char *ssh = getenv("GIT_SSH");
 629                 int putty = ssh && strcasestr(ssh, "plink");
 630                 if (!ssh) ssh = "ssh";
 631
 632                 *arg++ = ssh;
 633                 if (putty && !strcasestr(ssh, "tortoiseplink"))
 634                         *arg++ = "-batch";
 635                 if (port) {
 636                         /* P is for PuTTY, p is for OpenSSH */
 637                         *arg++ = putty ? "-P" : "-p";
 638                         *arg++ = port;
 639                 }
 640                 *arg++ = host;
 641         }
 642         else {
 643                 /* remove repo-local variables from the environment */
 644                 conn->env = local_repo_env;
 645                 conn->use_shell = 1;
 646         }
 647         *arg++ = cmd.buf;
 648         *arg = NULL;
 649
 650         if (start_command(conn))
 651                 die("unable to fork");
 652
 653         fd[0] = conn->out; /* read from child's stdout */
 654         fd[1] = conn->in;  /* write to child's stdin */
 655         strbuf_release(&cmd);
 656         free(url);
 657         if (free_path)
 658                 free(path);
 659         return conn;
 660 }
 661
 662 int git_connection_is_socket(struct child_process *conn)
 663 {
 664         return conn == &no_fork;
 665 }
 666
 667 int finish_connect(struct child_process *conn)
 668 {
 669         int code;
 670         if (!conn || git_connection_is_socket(conn))
 671                 return 0;
 672
 673         code = finish_command(conn);
 674         free(conn->argv);
 675         free(conn);
 676         return code;
 677 }