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 #include "string-list.h"
  10
  11 static char *server_capabilities;
  12 static const char *parse_feature_value(const char *, const char *, int *);
  13
  14 static int check_ref(const char *name, int len, unsigned int flags)
  15 {
  16         if (!flags)
  17                 return 1;
  18
  19         if (len < 5 || memcmp(name, "refs/", 5))
  20                 return 0;
  21
  22         /* Skip the "refs/" part */
  23         name += 5;
  24         len -= 5;
  25
  26         /* REF_NORMAL means that we don't want the magic fake tag refs */
  27         if ((flags & REF_NORMAL) && check_refname_format(name, 0))
  28                 return 0;
  29
  30         /* REF_HEADS means that we want regular branch heads */
  31         if ((flags & REF_HEADS) && !memcmp(name, "heads/", 6))
  32                 return 1;
  33
  34         /* REF_TAGS means that we want tags */
  35         if ((flags & REF_TAGS) && !memcmp(name, "tags/", 5))
  36                 return 1;
  37
  38         /* All type bits clear means that we are ok with anything */
  39         return !(flags & ~REF_NORMAL);
  40 }
  41
  42 int check_ref_type(const struct ref *ref, int flags)
  43 {
  44         return check_ref(ref->name, strlen(ref->name), flags);
  45 }
  46
  47 static void add_extra_have(struct extra_have_objects *extra, unsigned char *sha1)
  48 {
  49         ALLOC_GROW(extra->array, extra->nr + 1, extra->alloc);
  50         hashcpy(&(extra->array[extra->nr][0]), sha1);
  51         extra->nr++;
  52 }
  53
  54 static void die_initial_contact(int got_at_least_one_head)
  55 {
  56         if (got_at_least_one_head)
  57                 die("The remote end hung up upon initial contact");
  58         else
  59                 die("Could not read from remote repository.\n\n"
  60                     "Please make sure you have the correct access rights\n"
  61                     "and the repository exists.");
  62 }
  63
  64 static void parse_one_symref_info(struct string_list *symref, const char *val, int len)
  65 {
  66         char *sym, *target;
  67         struct string_list_item *item;
  68
  69         if (!len)
  70                 return; /* just "symref" */
  71         /* e.g. "symref=HEAD:refs/heads/master" */
  72         sym = xmalloc(len + 1);
  73         memcpy(sym, val, len);
  74         sym[len] = '\0';
  75         target = strchr(sym, ':');
  76         if (!target)
  77                 /* just "symref=something" */
  78                 goto reject;
  79         *(target++) = '\0';
  80         if (check_refname_format(sym, REFNAME_ALLOW_ONELEVEL) ||
  81             check_refname_format(target, REFNAME_ALLOW_ONELEVEL))
  82                 /* "symref=bogus:pair */
  83                 goto reject;
  84         item = string_list_append(symref, sym);
  85         item->util = target;
  86         return;
  87 reject:
  88         free(sym);
  89         return;
  90 }
  91
  92 static void annotate_refs_with_symref_info(struct ref *ref)
  93 {
  94         struct string_list symref = STRING_LIST_INIT_DUP;
  95         const char *feature_list = server_capabilities;
  96
  97         while (feature_list) {
  98                 int len;
  99                 const char *val;
 100
 101                 val = parse_feature_value(feature_list, "symref", &len);
 102                 if (!val)
 103                         break;
 104                 parse_one_symref_info(&symref, val, len);
 105                 feature_list = val + 1;
 106         }
 107         sort_string_list(&symref);
 108
 109         for (; ref; ref = ref->next) {
 110                 struct string_list_item *item;
 111                 item = string_list_lookup(&symref, ref->name);
 112                 if (!item)
 113                         continue;
 114                 ref->symref = xstrdup((char *)item->util);
 115         }
 116         string_list_clear(&symref, 0);
 117 }
 118
 119 /*
 120  * Read all the refs from the other end
 121  */
 122 struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
 123                               struct ref **list, unsigned int flags,
 124                               struct extra_have_objects *extra_have)
 125 {
 126         struct ref **orig_list = list;
 127         int got_at_least_one_head = 0;
 128
 129         *list = NULL;
 130         for (;;) {
 131                 struct ref *ref;
 132                 unsigned char old_sha1[20];
 133                 char *name;
 134                 int len, name_len;
 135                 char *buffer = packet_buffer;
 136
 137                 len = packet_read(in, &src_buf, &src_len,
 138                                   packet_buffer, sizeof(packet_buffer),
 139                                   PACKET_READ_GENTLE_ON_EOF |
 140                                   PACKET_READ_CHOMP_NEWLINE);
 141                 if (len < 0)
 142                         die_initial_contact(got_at_least_one_head);
 143
 144                 if (!len)
 145                         break;
 146
 147                 if (len > 4 && !prefixcmp(buffer, "ERR "))
 148                         die("remote error: %s", buffer + 4);
 149
 150                 if (len < 42 || get_sha1_hex(buffer, old_sha1) || buffer[40] != ' ')
 151                         die("protocol error: expected sha/ref, got '%s'", buffer);
 152                 name = buffer + 41;
 153
 154                 name_len = strlen(name);
 155                 if (len != name_len + 41) {
 156                         free(server_capabilities);
 157                         server_capabilities = xstrdup(name + name_len + 1);
 158                 }
 159
 160                 if (extra_have &&
 161                     name_len == 5 && !memcmp(".have", name, 5)) {
 162                         add_extra_have(extra_have, old_sha1);
 163                         continue;
 164                 }
 165
 166                 if (!check_ref(name, name_len, flags))
 167                         continue;
 168                 ref = alloc_ref(buffer + 41);
 169                 hashcpy(ref->old_sha1, old_sha1);
 170                 *list = ref;
 171                 list = &ref->next;
 172                 got_at_least_one_head = 1;
 173         }
 174
 175         annotate_refs_with_symref_info(*orig_list);
 176
 177         return list;
 178 }
 179
 180 static const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
 181 {
 182         int len;
 183
 184         if (!feature_list)
 185                 return NULL;
 186
 187         len = strlen(feature);
 188         while (*feature_list) {
 189                 const char *found = strstr(feature_list, feature);
 190                 if (!found)
 191                         return NULL;
 192                 if (feature_list == found || isspace(found[-1])) {
 193                         const char *value = found + len;
 194                         /* feature with no value (e.g., "thin-pack") */
 195                         if (!*value || isspace(*value)) {
 196                                 if (lenp)
 197                                         *lenp = 0;
 198                                 return value;
 199                         }
 200                         /* feature with a value (e.g., "agent=git/1.2.3") */
 201                         else if (*value == '=') {
 202                                 value++;
 203                                 if (lenp)
 204                                         *lenp = strcspn(value, " \t\n");
 205                                 return value;
 206                         }
 207                         /*
 208                          * otherwise we matched a substring of another feature;
 209                          * keep looking
 210                          */
 211                 }
 212                 feature_list = found + 1;
 213         }
 214         return NULL;
 215 }
 216
 217 int parse_feature_request(const char *feature_list, const char *feature)
 218 {
 219         return !!parse_feature_value(feature_list, feature, NULL);
 220 }
 221
 222 const char *server_feature_value(const char *feature, int *len)
 223 {
 224         return parse_feature_value(server_capabilities, feature, len);
 225 }
 226
 227 int server_supports(const char *feature)
 228 {
 229         return !!server_feature_value(feature, NULL);
 230 }
 231
 232 enum protocol {
 233         PROTO_LOCAL = 1,
 234         PROTO_SSH,
 235         PROTO_GIT
 236 };
 237
 238 static enum protocol get_protocol(const char *name)
 239 {
 240         if (!strcmp(name, "ssh"))
 241                 return PROTO_SSH;
 242         if (!strcmp(name, "git"))
 243                 return PROTO_GIT;
 244         if (!strcmp(name, "git+ssh"))
 245                 return PROTO_SSH;
 246         if (!strcmp(name, "ssh+git"))
 247                 return PROTO_SSH;
 248         if (!strcmp(name, "file"))
 249                 return PROTO_LOCAL;
 250         die("I don't handle protocol '%s'", name);
 251 }
 252
 253 #define STR_(s) # s
 254 #define STR(s)  STR_(s)
 255
 256 static void get_host_and_port(char **host, const char **port)
 257 {
 258         char *colon, *end;
 259
 260         if (*host[0] == '[') {
 261                 end = strchr(*host + 1, ']');
 262                 if (end) {
 263                         *end = 0;
 264                         end++;
 265                         (*host)++;
 266                 } else
 267                         end = *host;
 268         } else
 269                 end = *host;
 270         colon = strchr(end, ':');
 271
 272         if (colon) {
 273                 *colon = 0;
 274                 *port = colon + 1;
 275         }
 276 }
 277
 278 static void enable_keepalive(int sockfd)
 279 {
 280         int ka = 1;
 281
 282         if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
 283                 fprintf(stderr, "unable to set SO_KEEPALIVE on socket: %s\n",
 284                         strerror(errno));
 285 }
 286
 287 #ifndef NO_IPV6
 288
 289 static const char *ai_name(const struct addrinfo *ai)
 290 {
 291         static char addr[NI_MAXHOST];
 292         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
 293                         NI_NUMERICHOST) != 0)
 294                 strcpy(addr, "(unknown)");
 295
 296         return addr;
 297 }
 298
 299 /*
 300  * Returns a connected socket() fd, or else die()s.
 301  */
 302 static int git_tcp_connect_sock(char *host, int flags)
 303 {
 304         struct strbuf error_message = STRBUF_INIT;
 305         int sockfd = -1;
 306         const char *port = STR(DEFAULT_GIT_PORT);
 307         struct addrinfo hints, *ai0, *ai;
 308         int gai;
 309         int cnt = 0;
 310
 311         get_host_and_port(&host, &port);
 312         if (!*port)
 313                 port = "<none>";
 314
 315         memset(&hints, 0, sizeof(hints));
 316         hints.ai_socktype = SOCK_STREAM;
 317         hints.ai_protocol = IPPROTO_TCP;
 318
 319         if (flags & CONNECT_VERBOSE)
 320                 fprintf(stderr, "Looking up %s ... ", host);
 321
 322         gai = getaddrinfo(host, port, &hints, &ai);
 323         if (gai)
 324                 die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
 325
 326         if (flags & CONNECT_VERBOSE)
 327                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 328
 329         for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
 330                 sockfd = socket(ai->ai_family,
 331                                 ai->ai_socktype, ai->ai_protocol);
 332                 if ((sockfd < 0) ||
 333                     (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
 334                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 335                                     host, cnt, ai_name(ai), strerror(errno));
 336                         if (0 <= sockfd)
 337                                 close(sockfd);
 338                         sockfd = -1;
 339                         continue;
 340                 }
 341                 if (flags & CONNECT_VERBOSE)
 342                         fprintf(stderr, "%s ", ai_name(ai));
 343                 break;
 344         }
 345
 346         freeaddrinfo(ai0);
 347
 348         if (sockfd < 0)
 349                 die("unable to connect to %s:\n%s", host, error_message.buf);
 350
 351         enable_keepalive(sockfd);
 352
 353         if (flags & CONNECT_VERBOSE)
 354                 fprintf(stderr, "done.\n");
 355
 356         strbuf_release(&error_message);
 357
 358         return sockfd;
 359 }
 360
 361 #else /* NO_IPV6 */
 362
 363 /*
 364  * Returns a connected socket() fd, or else die()s.
 365  */
 366 static int git_tcp_connect_sock(char *host, int flags)
 367 {
 368         struct strbuf error_message = STRBUF_INIT;
 369         int sockfd = -1;
 370         const char *port = STR(DEFAULT_GIT_PORT);
 371         char *ep;
 372         struct hostent *he;
 373         struct sockaddr_in sa;
 374         char **ap;
 375         unsigned int nport;
 376         int cnt;
 377
 378         get_host_and_port(&host, &port);
 379
 380         if (flags & CONNECT_VERBOSE)
 381                 fprintf(stderr, "Looking up %s ... ", host);
 382
 383         he = gethostbyname(host);
 384         if (!he)
 385                 die("Unable to look up %s (%s)", host, hstrerror(h_errno));
 386         nport = strtoul(port, &ep, 10);
 387         if ( ep == port || *ep ) {
 388                 /* Not numeric */
 389                 struct servent *se = getservbyname(port,"tcp");
 390                 if ( !se )
 391                         die("Unknown port %s", port);
 392                 nport = se->s_port;
 393         }
 394
 395         if (flags & CONNECT_VERBOSE)
 396                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 397
 398         for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
 399                 memset(&sa, 0, sizeof sa);
 400                 sa.sin_family = he->h_addrtype;
 401                 sa.sin_port = htons(nport);
 402                 memcpy(&sa.sin_addr, *ap, he->h_length);
 403
 404                 sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 405                 if ((sockfd < 0) ||
 406                     connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 407                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 408                                 host,
 409                                 cnt,
 410                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr),
 411                                 strerror(errno));
 412                         if (0 <= sockfd)
 413                                 close(sockfd);
 414                         sockfd = -1;
 415                         continue;
 416                 }
 417                 if (flags & CONNECT_VERBOSE)
 418                         fprintf(stderr, "%s ",
 419                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr));
 420                 break;
 421         }
 422
 423         if (sockfd < 0)
 424                 die("unable to connect to %s:\n%s", host, error_message.buf);
 425
 426         enable_keepalive(sockfd);
 427
 428         if (flags & CONNECT_VERBOSE)
 429                 fprintf(stderr, "done.\n");
 430
 431         return sockfd;
 432 }
 433
 434 #endif /* NO_IPV6 */
 435
 436
 437 static void git_tcp_connect(int fd[2], char *host, int flags)
 438 {
 439         int sockfd = git_tcp_connect_sock(host, flags);
 440
 441         fd[0] = sockfd;
 442         fd[1] = dup(sockfd);
 443 }
 444
 445
 446 static char *git_proxy_command;
 447
 448 static int git_proxy_command_options(const char *var, const char *value,
 449                 void *cb)
 450 {
 451         if (!strcmp(var, "core.gitproxy")) {
 452                 const char *for_pos;
 453                 int matchlen = -1;
 454                 int hostlen;
 455                 const char *rhost_name = cb;
 456                 int rhost_len = strlen(rhost_name);
 457
 458                 if (git_proxy_command)
 459                         return 0;
 460                 if (!value)
 461                         return config_error_nonbool(var);
 462                 /* [core]
 463                  * ;# matches www.kernel.org as well
 464                  * gitproxy = netcatter-1 for kernel.org
 465                  * gitproxy = netcatter-2 for sample.xz
 466                  * gitproxy = netcatter-default
 467                  */
 468                 for_pos = strstr(value, " for ");
 469                 if (!for_pos)
 470                         /* matches everybody */
 471                         matchlen = strlen(value);
 472                 else {
 473                         hostlen = strlen(for_pos + 5);
 474                         if (rhost_len < hostlen)
 475                                 matchlen = -1;
 476                         else if (!strncmp(for_pos + 5,
 477                                           rhost_name + rhost_len - hostlen,
 478                                           hostlen) &&
 479                                  ((rhost_len == hostlen) ||
 480                                   rhost_name[rhost_len - hostlen -1] == '.'))
 481                                 matchlen = for_pos - value;
 482                         else
 483                                 matchlen = -1;
 484                 }
 485                 if (0 <= matchlen) {
 486                         /* core.gitproxy = none for kernel.org */
 487                         if (matchlen == 4 &&
 488                             !memcmp(value, "none", 4))
 489                                 matchlen = 0;
 490                         git_proxy_command = xmemdupz(value, matchlen);
 491                 }
 492                 return 0;
 493         }
 494
 495         return git_default_config(var, value, cb);
 496 }
 497
 498 static int git_use_proxy(const char *host)
 499 {
 500         git_proxy_command = getenv("GIT_PROXY_COMMAND");
 501         git_config(git_proxy_command_options, (void*)host);
 502         return (git_proxy_command && *git_proxy_command);
 503 }
 504
 505 static struct child_process *git_proxy_connect(int fd[2], char *host)
 506 {
 507         const char *port = STR(DEFAULT_GIT_PORT);
 508         const char **argv;
 509         struct child_process *proxy;
 510
 511         get_host_and_port(&host, &port);
 512
 513         argv = xmalloc(sizeof(*argv) * 4);
 514         argv[0] = git_proxy_command;
 515         argv[1] = host;
 516         argv[2] = port;
 517         argv[3] = NULL;
 518         proxy = xcalloc(1, sizeof(*proxy));
 519         proxy->argv = argv;
 520         proxy->in = -1;
 521         proxy->out = -1;
 522         if (start_command(proxy))
 523                 die("cannot start proxy %s", argv[0]);
 524         fd[0] = proxy->out; /* read from proxy stdout */
 525         fd[1] = proxy->in;  /* write to proxy stdin */
 526         return proxy;
 527 }
 528
 529 #define MAX_CMD_LEN 1024
 530
 531 static char *get_port(char *host)
 532 {
 533         char *end;
 534         char *p = strchr(host, ':');
 535
 536         if (p) {
 537                 long port = strtol(p + 1, &end, 10);
 538                 if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
 539                         *p = '\0';
 540                         return p+1;
 541                 }
 542         }
 543
 544         return NULL;
 545 }
 546
 547 static struct child_process no_fork;
 548
 549 /*
 550  * This returns a dummy child_process if the transport protocol does not
 551  * need fork(2), or a struct child_process object if it does.  Once done,
 552  * finish the connection with finish_connect() with the value returned from
 553  * this function (it is safe to call finish_connect() with NULL to support
 554  * the former case).
 555  *
 556  * If it returns, the connect is successful; it just dies on errors (this
 557  * will hopefully be changed in a libification effort, to return NULL when
 558  * the connection failed).
 559  */
 560 struct child_process *git_connect(int fd[2], const char *url_orig,
 561                                   const char *prog, int flags)
 562 {
 563         char *url;
 564         char *host, *path;
 565         char *end;
 566         int c;
 567         struct child_process *conn = &no_fork;
 568         enum protocol protocol = PROTO_LOCAL;
 569         int free_path = 0;
 570         char *port = NULL;
 571         const char **arg;
 572         struct strbuf cmd;
 573
 574         /* Without this we cannot rely on waitpid() to tell
 575          * what happened to our children.
 576          */
 577         signal(SIGCHLD, SIG_DFL);
 578
 579         if (is_url(url_orig))
 580                 url = url_decode(url_orig);
 581         else
 582                 url = xstrdup(url_orig);
 583
 584         host = strstr(url, "://");
 585         if (host) {
 586                 *host = '\0';
 587                 protocol = get_protocol(url);
 588                 host += 3;
 589                 c = '/';
 590         } else {
 591                 host = url;
 592                 c = ':';
 593         }
 594
 595         /*
 596          * Don't do destructive transforms with git:// as that
 597          * protocol code does '[]' unwrapping of its own.
 598          */
 599         if (host[0] == '[') {
 600                 end = strchr(host + 1, ']');
 601                 if (end) {
 602                         if (protocol != PROTO_GIT) {
 603                                 *end = 0;
 604                                 host++;
 605                         }
 606                         end++;
 607                 } else
 608                         end = host;
 609         } else
 610                 end = host;
 611
 612         path = strchr(end, c);
 613         if (path && !has_dos_drive_prefix(end)) {
 614                 if (c == ':') {
 615                         if (path < strchrnul(host, '/')) {
 616                                 protocol = PROTO_SSH;
 617                                 *path++ = '\0';
 618                         } else /* '/' in the host part, assume local path */
 619                                 path = end;
 620                 }
 621         } else
 622                 path = end;
 623
 624         if (!path || !*path)
 625                 die("No path specified. See 'man git-pull' for valid url syntax");
 626
 627         /*
 628          * null-terminate hostname and point path to ~ for URL's like this:
 629          *    ssh://host.xz/~user/repo
 630          */
 631         if (protocol != PROTO_LOCAL && host != url) {
 632                 char *ptr = path;
 633                 if (path[1] == '~')
 634                         path++;
 635                 else {
 636                         path = xstrdup(ptr);
 637                         free_path = 1;
 638                 }
 639
 640                 *ptr = '\0';
 641         }
 642
 643         /*
 644          * Add support for ssh port: ssh://host.xy:<port>/...
 645          */
 646         if (protocol == PROTO_SSH && host != url)
 647                 port = get_port(end);
 648
 649         if (protocol == PROTO_GIT) {
 650                 /* These underlying connection commands die() if they
 651                  * cannot connect.
 652                  */
 653                 char *target_host = xstrdup(host);
 654                 if (git_use_proxy(host))
 655                         conn = git_proxy_connect(fd, host);
 656                 else
 657                         git_tcp_connect(fd, host, flags);
 658                 /*
 659                  * Separate original protocol components prog and path
 660                  * from extended host header with a NUL byte.
 661                  *
 662                  * Note: Do not add any other headers here!  Doing so
 663                  * will cause older git-daemon servers to crash.
 664                  */
 665                 packet_write(fd[1],
 666                              "%s %s%chost=%s%c",
 667                              prog, path, 0,
 668                              target_host, 0);
 669                 free(target_host);
 670                 free(url);
 671                 if (free_path)
 672                         free(path);
 673                 return conn;
 674         }
 675
 676         conn = xcalloc(1, sizeof(*conn));
 677
 678         strbuf_init(&cmd, MAX_CMD_LEN);
 679         strbuf_addstr(&cmd, prog);
 680         strbuf_addch(&cmd, ' ');
 681         sq_quote_buf(&cmd, path);
 682         if (cmd.len >= MAX_CMD_LEN)
 683                 die("command line too long");
 684
 685         conn->in = conn->out = -1;
 686         conn->argv = arg = xcalloc(7, sizeof(*arg));
 687         if (protocol == PROTO_SSH) {
 688                 const char *ssh = getenv("GIT_SSH");
 689                 int putty = ssh && strcasestr(ssh, "plink");
 690                 if (!ssh) ssh = "ssh";
 691
 692                 *arg++ = ssh;
 693                 if (putty && !strcasestr(ssh, "tortoiseplink"))
 694                         *arg++ = "-batch";
 695                 if (port) {
 696                         /* P is for PuTTY, p is for OpenSSH */
 697                         *arg++ = putty ? "-P" : "-p";
 698                         *arg++ = port;
 699                 }
 700                 *arg++ = host;
 701         }
 702         else {
 703                 /* remove repo-local variables from the environment */
 704                 conn->env = local_repo_env;
 705                 conn->use_shell = 1;
 706         }
 707         *arg++ = cmd.buf;
 708         *arg = NULL;
 709
 710         if (start_command(conn))
 711                 die("unable to fork");
 712
 713         fd[0] = conn->out; /* read from child's stdout */
 714         fd[1] = conn->in;  /* write to child's stdin */
 715         strbuf_release(&cmd);
 716         free(url);
 717         if (free_path)
 718                 free(path);
 719         return conn;
 720 }
 721
 722 int git_connection_is_socket(struct child_process *conn)
 723 {
 724         return conn == &no_fork;
 725 }
 726
 727 int finish_connect(struct child_process *conn)
 728 {
 729         int code;
 730         if (!conn || git_connection_is_socket(conn))
 731                 return 0;
 732
 733         code = finish_command(conn);
 734         free(conn->argv);
 735         free(conn);
 736         return code;
 737 }