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 #include "string-list.h"
  11 #include "sha1-array.h"
  12
  13 static char *server_capabilities;
  14 static const char *parse_feature_value(const char *, const char *, int *);
  15
  16 static int check_ref(const char *name, int len, unsigned int flags)
  17 {
  18         if (!flags)
  19                 return 1;
  20
  21         if (len < 5 || memcmp(name, "refs/", 5))
  22                 return 0;
  23
  24         /* Skip the "refs/" part */
  25         name += 5;
  26         len -= 5;
  27
  28         /* REF_NORMAL means that we don't want the magic fake tag refs */
  29         if ((flags & REF_NORMAL) && check_refname_format(name, 0))
  30                 return 0;
  31
  32         /* REF_HEADS means that we want regular branch heads */
  33         if ((flags & REF_HEADS) && !memcmp(name, "heads/", 6))
  34                 return 1;
  35
  36         /* REF_TAGS means that we want tags */
  37         if ((flags & REF_TAGS) && !memcmp(name, "tags/", 5))
  38                 return 1;
  39
  40         /* All type bits clear means that we are ok with anything */
  41         return !(flags & ~REF_NORMAL);
  42 }
  43
  44 int check_ref_type(const struct ref *ref, int flags)
  45 {
  46         return check_ref(ref->name, strlen(ref->name), flags);
  47 }
  48
  49 static void die_initial_contact(int got_at_least_one_head)
  50 {
  51         if (got_at_least_one_head)
  52                 die("The remote end hung up upon initial contact");
  53         else
  54                 die("Could not read from remote repository.\n\n"
  55                     "Please make sure you have the correct access rights\n"
  56                     "and the repository exists.");
  57 }
  58
  59 static void parse_one_symref_info(struct string_list *symref, const char *val, int len)
  60 {
  61         char *sym, *target;
  62         struct string_list_item *item;
  63
  64         if (!len)
  65                 return; /* just "symref" */
  66         /* e.g. "symref=HEAD:refs/heads/master" */
  67         sym = xmalloc(len + 1);
  68         memcpy(sym, val, len);
  69         sym[len] = '\0';
  70         target = strchr(sym, ':');
  71         if (!target)
  72                 /* just "symref=something" */
  73                 goto reject;
  74         *(target++) = '\0';
  75         if (check_refname_format(sym, REFNAME_ALLOW_ONELEVEL) ||
  76             check_refname_format(target, REFNAME_ALLOW_ONELEVEL))
  77                 /* "symref=bogus:pair */
  78                 goto reject;
  79         item = string_list_append(symref, sym);
  80         item->util = target;
  81         return;
  82 reject:
  83         free(sym);
  84         return;
  85 }
  86
  87 static void annotate_refs_with_symref_info(struct ref *ref)
  88 {
  89         struct string_list symref = STRING_LIST_INIT_DUP;
  90         const char *feature_list = server_capabilities;
  91
  92         while (feature_list) {
  93                 int len;
  94                 const char *val;
  95
  96                 val = parse_feature_value(feature_list, "symref", &len);
  97                 if (!val)
  98                         break;
  99                 parse_one_symref_info(&symref, val, len);
 100                 feature_list = val + 1;
 101         }
 102         sort_string_list(&symref);
 103
 104         for (; ref; ref = ref->next) {
 105                 struct string_list_item *item;
 106                 item = string_list_lookup(&symref, ref->name);
 107                 if (!item)
 108                         continue;
 109                 ref->symref = xstrdup((char *)item->util);
 110         }
 111         string_list_clear(&symref, 0);
 112 }
 113
 114 /*
 115  * Read all the refs from the other end
 116  */
 117 struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
 118                               struct ref **list, unsigned int flags,
 119                               struct sha1_array *extra_have)
 120 {
 121         struct ref **orig_list = list;
 122         int got_at_least_one_head = 0;
 123
 124         *list = NULL;
 125         for (;;) {
 126                 struct ref *ref;
 127                 unsigned char old_sha1[20];
 128                 char *name;
 129                 int len, name_len;
 130                 char *buffer = packet_buffer;
 131
 132                 len = packet_read(in, &src_buf, &src_len,
 133                                   packet_buffer, sizeof(packet_buffer),
 134                                   PACKET_READ_GENTLE_ON_EOF |
 135                                   PACKET_READ_CHOMP_NEWLINE);
 136                 if (len < 0)
 137                         die_initial_contact(got_at_least_one_head);
 138
 139                 if (!len)
 140                         break;
 141
 142                 if (len > 4 && !prefixcmp(buffer, "ERR "))
 143                         die("remote error: %s", buffer + 4);
 144
 145                 if (len < 42 || get_sha1_hex(buffer, old_sha1) || buffer[40] != ' ')
 146                         die("protocol error: expected sha/ref, got '%s'", buffer);
 147                 name = buffer + 41;
 148
 149                 name_len = strlen(name);
 150                 if (len != name_len + 41) {
 151                         free(server_capabilities);
 152                         server_capabilities = xstrdup(name + name_len + 1);
 153                 }
 154
 155                 if (extra_have &&
 156                     name_len == 5 && !memcmp(".have", name, 5)) {
 157                         sha1_array_append(extra_have, old_sha1);
 158                         continue;
 159                 }
 160
 161                 if (!check_ref(name, name_len, flags))
 162                         continue;
 163                 ref = alloc_ref(buffer + 41);
 164                 hashcpy(ref->old_sha1, old_sha1);
 165                 *list = ref;
 166                 list = &ref->next;
 167                 got_at_least_one_head = 1;
 168         }
 169
 170         annotate_refs_with_symref_info(*orig_list);
 171
 172         return list;
 173 }
 174
 175 static const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
 176 {
 177         int len;
 178
 179         if (!feature_list)
 180                 return NULL;
 181
 182         len = strlen(feature);
 183         while (*feature_list) {
 184                 const char *found = strstr(feature_list, feature);
 185                 if (!found)
 186                         return NULL;
 187                 if (feature_list == found || isspace(found[-1])) {
 188                         const char *value = found + len;
 189                         /* feature with no value (e.g., "thin-pack") */
 190                         if (!*value || isspace(*value)) {
 191                                 if (lenp)
 192                                         *lenp = 0;
 193                                 return value;
 194                         }
 195                         /* feature with a value (e.g., "agent=git/1.2.3") */
 196                         else if (*value == '=') {
 197                                 value++;
 198                                 if (lenp)
 199                                         *lenp = strcspn(value, " \t\n");
 200                                 return value;
 201                         }
 202                         /*
 203                          * otherwise we matched a substring of another feature;
 204                          * keep looking
 205                          */
 206                 }
 207                 feature_list = found + 1;
 208         }
 209         return NULL;
 210 }
 211
 212 int parse_feature_request(const char *feature_list, const char *feature)
 213 {
 214         return !!parse_feature_value(feature_list, feature, NULL);
 215 }
 216
 217 const char *server_feature_value(const char *feature, int *len)
 218 {
 219         return parse_feature_value(server_capabilities, feature, len);
 220 }
 221
 222 int server_supports(const char *feature)
 223 {
 224         return !!server_feature_value(feature, NULL);
 225 }
 226
 227 enum protocol {
 228         PROTO_LOCAL = 1,
 229         PROTO_SSH,
 230         PROTO_GIT
 231 };
 232
 233 static enum protocol get_protocol(const char *name)
 234 {
 235         if (!strcmp(name, "ssh"))
 236                 return PROTO_SSH;
 237         if (!strcmp(name, "git"))
 238                 return PROTO_GIT;
 239         if (!strcmp(name, "git+ssh"))
 240                 return PROTO_SSH;
 241         if (!strcmp(name, "ssh+git"))
 242                 return PROTO_SSH;
 243         if (!strcmp(name, "file"))
 244                 return PROTO_LOCAL;
 245         die("I don't handle protocol '%s'", name);
 246 }
 247
 248 #define STR_(s) # s
 249 #define STR(s)  STR_(s)
 250
 251 static void get_host_and_port(char **host, const char **port)
 252 {
 253         char *colon, *end;
 254
 255         if (*host[0] == '[') {
 256                 end = strchr(*host + 1, ']');
 257                 if (end) {
 258                         *end = 0;
 259                         end++;
 260                         (*host)++;
 261                 } else
 262                         end = *host;
 263         } else
 264                 end = *host;
 265         colon = strchr(end, ':');
 266
 267         if (colon) {
 268                 *colon = 0;
 269                 *port = colon + 1;
 270         }
 271 }
 272
 273 static void enable_keepalive(int sockfd)
 274 {
 275         int ka = 1;
 276
 277         if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
 278                 fprintf(stderr, "unable to set SO_KEEPALIVE on socket: %s\n",
 279                         strerror(errno));
 280 }
 281
 282 #ifndef NO_IPV6
 283
 284 static const char *ai_name(const struct addrinfo *ai)
 285 {
 286         static char addr[NI_MAXHOST];
 287         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
 288                         NI_NUMERICHOST) != 0)
 289                 strcpy(addr, "(unknown)");
 290
 291         return addr;
 292 }
 293
 294 /*
 295  * Returns a connected socket() fd, or else die()s.
 296  */
 297 static int git_tcp_connect_sock(char *host, int flags)
 298 {
 299         struct strbuf error_message = STRBUF_INIT;
 300         int sockfd = -1;
 301         const char *port = STR(DEFAULT_GIT_PORT);
 302         struct addrinfo hints, *ai0, *ai;
 303         int gai;
 304         int cnt = 0;
 305
 306         get_host_and_port(&host, &port);
 307         if (!*port)
 308                 port = "<none>";
 309
 310         memset(&hints, 0, sizeof(hints));
 311         hints.ai_socktype = SOCK_STREAM;
 312         hints.ai_protocol = IPPROTO_TCP;
 313
 314         if (flags & CONNECT_VERBOSE)
 315                 fprintf(stderr, "Looking up %s ... ", host);
 316
 317         gai = getaddrinfo(host, port, &hints, &ai);
 318         if (gai)
 319                 die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
 320
 321         if (flags & CONNECT_VERBOSE)
 322                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 323
 324         for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
 325                 sockfd = socket(ai->ai_family,
 326                                 ai->ai_socktype, ai->ai_protocol);
 327                 if ((sockfd < 0) ||
 328                     (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
 329                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 330                                     host, cnt, ai_name(ai), strerror(errno));
 331                         if (0 <= sockfd)
 332                                 close(sockfd);
 333                         sockfd = -1;
 334                         continue;
 335                 }
 336                 if (flags & CONNECT_VERBOSE)
 337                         fprintf(stderr, "%s ", ai_name(ai));
 338                 break;
 339         }
 340
 341         freeaddrinfo(ai0);
 342
 343         if (sockfd < 0)
 344                 die("unable to connect to %s:\n%s", host, error_message.buf);
 345
 346         enable_keepalive(sockfd);
 347
 348         if (flags & CONNECT_VERBOSE)
 349                 fprintf(stderr, "done.\n");
 350
 351         strbuf_release(&error_message);
 352
 353         return sockfd;
 354 }
 355
 356 #else /* NO_IPV6 */
 357
 358 /*
 359  * Returns a connected socket() fd, or else die()s.
 360  */
 361 static int git_tcp_connect_sock(char *host, int flags)
 362 {
 363         struct strbuf error_message = STRBUF_INIT;
 364         int sockfd = -1;
 365         const char *port = STR(DEFAULT_GIT_PORT);
 366         char *ep;
 367         struct hostent *he;
 368         struct sockaddr_in sa;
 369         char **ap;
 370         unsigned int nport;
 371         int cnt;
 372
 373         get_host_and_port(&host, &port);
 374
 375         if (flags & CONNECT_VERBOSE)
 376                 fprintf(stderr, "Looking up %s ... ", host);
 377
 378         he = gethostbyname(host);
 379         if (!he)
 380                 die("Unable to look up %s (%s)", host, hstrerror(h_errno));
 381         nport = strtoul(port, &ep, 10);
 382         if ( ep == port || *ep ) {
 383                 /* Not numeric */
 384                 struct servent *se = getservbyname(port,"tcp");
 385                 if ( !se )
 386                         die("Unknown port %s", port);
 387                 nport = se->s_port;
 388         }
 389
 390         if (flags & CONNECT_VERBOSE)
 391                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 392
 393         for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
 394                 memset(&sa, 0, sizeof sa);
 395                 sa.sin_family = he->h_addrtype;
 396                 sa.sin_port = htons(nport);
 397                 memcpy(&sa.sin_addr, *ap, he->h_length);
 398
 399                 sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 400                 if ((sockfd < 0) ||
 401                     connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 402                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 403                                 host,
 404                                 cnt,
 405                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr),
 406                                 strerror(errno));
 407                         if (0 <= sockfd)
 408                                 close(sockfd);
 409                         sockfd = -1;
 410                         continue;
 411                 }
 412                 if (flags & CONNECT_VERBOSE)
 413                         fprintf(stderr, "%s ",
 414                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr));
 415                 break;
 416         }
 417
 418         if (sockfd < 0)
 419                 die("unable to connect to %s:\n%s", host, error_message.buf);
 420
 421         enable_keepalive(sockfd);
 422
 423         if (flags & CONNECT_VERBOSE)
 424                 fprintf(stderr, "done.\n");
 425
 426         return sockfd;
 427 }
 428
 429 #endif /* NO_IPV6 */
 430
 431
 432 static void git_tcp_connect(int fd[2], char *host, int flags)
 433 {
 434         int sockfd = git_tcp_connect_sock(host, flags);
 435
 436         fd[0] = sockfd;
 437         fd[1] = dup(sockfd);
 438 }
 439
 440
 441 static char *git_proxy_command;
 442
 443 static int git_proxy_command_options(const char *var, const char *value,
 444                 void *cb)
 445 {
 446         if (!strcmp(var, "core.gitproxy")) {
 447                 const char *for_pos;
 448                 int matchlen = -1;
 449                 int hostlen;
 450                 const char *rhost_name = cb;
 451                 int rhost_len = strlen(rhost_name);
 452
 453                 if (git_proxy_command)
 454                         return 0;
 455                 if (!value)
 456                         return config_error_nonbool(var);
 457                 /* [core]
 458                  * ;# matches www.kernel.org as well
 459                  * gitproxy = netcatter-1 for kernel.org
 460                  * gitproxy = netcatter-2 for sample.xz
 461                  * gitproxy = netcatter-default
 462                  */
 463                 for_pos = strstr(value, " for ");
 464                 if (!for_pos)
 465                         /* matches everybody */
 466                         matchlen = strlen(value);
 467                 else {
 468                         hostlen = strlen(for_pos + 5);
 469                         if (rhost_len < hostlen)
 470                                 matchlen = -1;
 471                         else if (!strncmp(for_pos + 5,
 472                                           rhost_name + rhost_len - hostlen,
 473                                           hostlen) &&
 474                                  ((rhost_len == hostlen) ||
 475                                   rhost_name[rhost_len - hostlen -1] == '.'))
 476                                 matchlen = for_pos - value;
 477                         else
 478                                 matchlen = -1;
 479                 }
 480                 if (0 <= matchlen) {
 481                         /* core.gitproxy = none for kernel.org */
 482                         if (matchlen == 4 &&
 483                             !memcmp(value, "none", 4))
 484                                 matchlen = 0;
 485                         git_proxy_command = xmemdupz(value, matchlen);
 486                 }
 487                 return 0;
 488         }
 489
 490         return git_default_config(var, value, cb);
 491 }
 492
 493 static int git_use_proxy(const char *host)
 494 {
 495         git_proxy_command = getenv("GIT_PROXY_COMMAND");
 496         git_config(git_proxy_command_options, (void*)host);
 497         return (git_proxy_command && *git_proxy_command);
 498 }
 499
 500 static struct child_process *git_proxy_connect(int fd[2], char *host)
 501 {
 502         const char *port = STR(DEFAULT_GIT_PORT);
 503         const char **argv;
 504         struct child_process *proxy;
 505
 506         get_host_and_port(&host, &port);
 507
 508         argv = xmalloc(sizeof(*argv) * 4);
 509         argv[0] = git_proxy_command;
 510         argv[1] = host;
 511         argv[2] = port;
 512         argv[3] = NULL;
 513         proxy = xcalloc(1, sizeof(*proxy));
 514         proxy->argv = argv;
 515         proxy->in = -1;
 516         proxy->out = -1;
 517         if (start_command(proxy))
 518                 die("cannot start proxy %s", argv[0]);
 519         fd[0] = proxy->out; /* read from proxy stdout */
 520         fd[1] = proxy->in;  /* write to proxy stdin */
 521         return proxy;
 522 }
 523
 524 #define MAX_CMD_LEN 1024
 525
 526 static char *get_port(char *host)
 527 {
 528         char *end;
 529         char *p = strchr(host, ':');
 530
 531         if (p) {
 532                 long port = strtol(p + 1, &end, 10);
 533                 if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
 534                         *p = '\0';
 535                         return p+1;
 536                 }
 537         }
 538
 539         return NULL;
 540 }
 541
 542 static struct child_process no_fork;
 543
 544 /*
 545  * This returns a dummy child_process if the transport protocol does not
 546  * need fork(2), or a struct child_process object if it does.  Once done,
 547  * finish the connection with finish_connect() with the value returned from
 548  * this function (it is safe to call finish_connect() with NULL to support
 549  * the former case).
 550  *
 551  * If it returns, the connect is successful; it just dies on errors (this
 552  * will hopefully be changed in a libification effort, to return NULL when
 553  * the connection failed).
 554  */
 555 struct child_process *git_connect(int fd[2], const char *url_orig,
 556                                   const char *prog, int flags)
 557 {
 558         char *url;
 559         char *host, *path;
 560         char *end;
 561         int c;
 562         struct child_process *conn = &no_fork;
 563         enum protocol protocol = PROTO_LOCAL;
 564         int free_path = 0;
 565         char *port = NULL;
 566         const char **arg;
 567         struct strbuf cmd;
 568
 569         /* Without this we cannot rely on waitpid() to tell
 570          * what happened to our children.
 571          */
 572         signal(SIGCHLD, SIG_DFL);
 573
 574         if (is_url(url_orig))
 575                 url = url_decode(url_orig);
 576         else
 577                 url = xstrdup(url_orig);
 578
 579         host = strstr(url, "://");
 580         if (host) {
 581                 *host = '\0';
 582                 protocol = get_protocol(url);
 583                 host += 3;
 584                 c = '/';
 585         } else {
 586                 host = url;
 587                 c = ':';
 588         }
 589
 590         /*
 591          * Don't do destructive transforms with git:// as that
 592          * protocol code does '[]' unwrapping of its own.
 593          */
 594         if (host[0] == '[') {
 595                 end = strchr(host + 1, ']');
 596                 if (end) {
 597                         if (protocol != PROTO_GIT) {
 598                                 *end = 0;
 599                                 host++;
 600                         }
 601                         end++;
 602                 } else
 603                         end = host;
 604         } else
 605                 end = host;
 606
 607         path = strchr(end, c);
 608         if (path && !has_dos_drive_prefix(end)) {
 609                 if (c == ':') {
 610                         if (host != url || path < strchrnul(host, '/')) {
 611                                 protocol = PROTO_SSH;
 612                                 *path++ = '\0';
 613                         } else /* '/' in the host part, assume local path */
 614                                 path = end;
 615                 }
 616         } else
 617                 path = end;
 618
 619         if (!path || !*path)
 620                 die("No path specified. See 'man git-pull' for valid url syntax");
 621
 622         /*
 623          * null-terminate hostname and point path to ~ for URL's like this:
 624          *    ssh://host.xz/~user/repo
 625          */
 626         if (protocol != PROTO_LOCAL && host != url) {
 627                 char *ptr = path;
 628                 if (path[1] == '~')
 629                         path++;
 630                 else {
 631                         path = xstrdup(ptr);
 632                         free_path = 1;
 633                 }
 634
 635                 *ptr = '\0';
 636         }
 637
 638         /*
 639          * Add support for ssh port: ssh://host.xy:<port>/...
 640          */
 641         if (protocol == PROTO_SSH && host != url)
 642                 port = get_port(end);
 643
 644         if (protocol == PROTO_GIT) {
 645                 /* These underlying connection commands die() if they
 646                  * cannot connect.
 647                  */
 648                 char *target_host = xstrdup(host);
 649                 if (git_use_proxy(host))
 650                         conn = git_proxy_connect(fd, host);
 651                 else
 652                         git_tcp_connect(fd, host, flags);
 653                 /*
 654                  * Separate original protocol components prog and path
 655                  * from extended host header with a NUL byte.
 656                  *
 657                  * Note: Do not add any other headers here!  Doing so
 658                  * will cause older git-daemon servers to crash.
 659                  */
 660                 packet_write(fd[1],
 661                              "%s %s%chost=%s%c",
 662                              prog, path, 0,
 663                              target_host, 0);
 664                 free(target_host);
 665                 free(url);
 666                 if (free_path)
 667                         free(path);
 668                 return conn;
 669         }
 670
 671         conn = xcalloc(1, sizeof(*conn));
 672
 673         strbuf_init(&cmd, MAX_CMD_LEN);
 674         strbuf_addstr(&cmd, prog);
 675         strbuf_addch(&cmd, ' ');
 676         sq_quote_buf(&cmd, path);
 677         if (cmd.len >= MAX_CMD_LEN)
 678                 die("command line too long");
 679
 680         conn->in = conn->out = -1;
 681         conn->argv = arg = xcalloc(7, sizeof(*arg));
 682         if (protocol == PROTO_SSH) {
 683                 const char *ssh = getenv("GIT_SSH");
 684                 int putty = ssh && strcasestr(ssh, "plink");
 685                 if (!ssh) ssh = "ssh";
 686
 687                 *arg++ = ssh;
 688                 if (putty && !strcasestr(ssh, "tortoiseplink"))
 689                         *arg++ = "-batch";
 690                 if (port) {
 691                         /* P is for PuTTY, p is for OpenSSH */
 692                         *arg++ = putty ? "-P" : "-p";
 693                         *arg++ = port;
 694                 }
 695                 *arg++ = host;
 696         }
 697         else {
 698                 /* remove repo-local variables from the environment */
 699                 conn->env = local_repo_env;
 700                 conn->use_shell = 1;
 701         }
 702         *arg++ = cmd.buf;
 703         *arg = NULL;
 704
 705         if (start_command(conn))
 706                 die("unable to fork");
 707
 708         fd[0] = conn->out; /* read from child's stdout */
 709         fd[1] = conn->in;  /* write to child's stdin */
 710         strbuf_release(&cmd);
 711         free(url);
 712         if (free_path)
 713                 free(path);
 714         return conn;
 715 }
 716
 717 int git_connection_is_socket(struct child_process *conn)
 718 {
 719         return conn == &no_fork;
 720 }
 721
 722 int finish_connect(struct child_process *conn)
 723 {
 724         int code;
 725         if (!conn || git_connection_is_socket(conn))
 726                 return 0;
 727
 728         code = finish_command(conn);
 729         free(conn->argv);
 730         free(conn);
 731         return code;
 732 }