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
  12 static char *server_capabilities;
  13 static const char *parse_feature_value(const char *, const char *, int *);
  14
  15 static int check_ref(const char *name, int len, unsigned int flags)
  16 {
  17         if (!flags)
  18                 return 1;
  19
  20         if (len < 5 || memcmp(name, "refs/", 5))
  21                 return 0;
  22
  23         /* Skip the "refs/" part */
  24         name += 5;
  25         len -= 5;
  26
  27         /* REF_NORMAL means that we don't want the magic fake tag refs */
  28         if ((flags & REF_NORMAL) && check_refname_format(name, 0))
  29                 return 0;
  30
  31         /* REF_HEADS means that we want regular branch heads */
  32         if ((flags & REF_HEADS) && !memcmp(name, "heads/", 6))
  33                 return 1;
  34
  35         /* REF_TAGS means that we want tags */
  36         if ((flags & REF_TAGS) && !memcmp(name, "tags/", 5))
  37                 return 1;
  38
  39         /* All type bits clear means that we are ok with anything */
  40         return !(flags & ~REF_NORMAL);
  41 }
  42
  43 int check_ref_type(const struct ref *ref, int flags)
  44 {
  45         return check_ref(ref->name, strlen(ref->name), flags);
  46 }
  47
  48 static void add_extra_have(struct extra_have_objects *extra, unsigned char *sha1)
  49 {
  50         ALLOC_GROW(extra->array, extra->nr + 1, extra->alloc);
  51         hashcpy(&(extra->array[extra->nr][0]), sha1);
  52         extra->nr++;
  53 }
  54
  55 static void die_initial_contact(int got_at_least_one_head)
  56 {
  57         if (got_at_least_one_head)
  58                 die("The remote end hung up upon initial contact");
  59         else
  60                 die("Could not read from remote repository.\n\n"
  61                     "Please make sure you have the correct access rights\n"
  62                     "and the repository exists.");
  63 }
  64
  65 static void parse_one_symref_info(struct string_list *symref, const char *val, int len)
  66 {
  67         char *sym, *target;
  68         struct string_list_item *item;
  69
  70         if (!len)
  71                 return; /* just "symref" */
  72         /* e.g. "symref=HEAD:refs/heads/master" */
  73         sym = xmalloc(len + 1);
  74         memcpy(sym, val, len);
  75         sym[len] = '\0';
  76         target = strchr(sym, ':');
  77         if (!target)
  78                 /* just "symref=something" */
  79                 goto reject;
  80         *(target++) = '\0';
  81         if (check_refname_format(sym, REFNAME_ALLOW_ONELEVEL) ||
  82             check_refname_format(target, REFNAME_ALLOW_ONELEVEL))
  83                 /* "symref=bogus:pair */
  84                 goto reject;
  85         item = string_list_append(symref, sym);
  86         item->util = target;
  87         return;
  88 reject:
  89         free(sym);
  90         return;
  91 }
  92
  93 static void annotate_refs_with_symref_info(struct ref *ref)
  94 {
  95         struct string_list symref = STRING_LIST_INIT_DUP;
  96         const char *feature_list = server_capabilities;
  97
  98         while (feature_list) {
  99                 int len;
 100                 const char *val;
 101
 102                 val = parse_feature_value(feature_list, "symref", &len);
 103                 if (!val)
 104                         break;
 105                 parse_one_symref_info(&symref, val, len);
 106                 feature_list = val + 1;
 107         }
 108         sort_string_list(&symref);
 109
 110         for (; ref; ref = ref->next) {
 111                 struct string_list_item *item;
 112                 item = string_list_lookup(&symref, ref->name);
 113                 if (!item)
 114                         continue;
 115                 ref->symref = xstrdup((char *)item->util);
 116         }
 117         string_list_clear(&symref, 0);
 118 }
 119
 120 /*
 121  * Read all the refs from the other end
 122  */
 123 struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
 124                               struct ref **list, unsigned int flags,
 125                               struct extra_have_objects *extra_have)
 126 {
 127         struct ref **orig_list = list;
 128         int got_at_least_one_head = 0;
 129
 130         *list = NULL;
 131         for (;;) {
 132                 struct ref *ref;
 133                 unsigned char old_sha1[20];
 134                 char *name;
 135                 int len, name_len;
 136                 char *buffer = packet_buffer;
 137
 138                 len = packet_read(in, &src_buf, &src_len,
 139                                   packet_buffer, sizeof(packet_buffer),
 140                                   PACKET_READ_GENTLE_ON_EOF |
 141                                   PACKET_READ_CHOMP_NEWLINE);
 142                 if (len < 0)
 143                         die_initial_contact(got_at_least_one_head);
 144
 145                 if (!len)
 146                         break;
 147
 148                 if (len > 4 && !prefixcmp(buffer, "ERR "))
 149                         die("remote error: %s", buffer + 4);
 150
 151                 if (len < 42 || get_sha1_hex(buffer, old_sha1) || buffer[40] != ' ')
 152                         die("protocol error: expected sha/ref, got '%s'", buffer);
 153                 name = buffer + 41;
 154
 155                 name_len = strlen(name);
 156                 if (len != name_len + 41) {
 157                         free(server_capabilities);
 158                         server_capabilities = xstrdup(name + name_len + 1);
 159                 }
 160
 161                 if (extra_have &&
 162                     name_len == 5 && !memcmp(".have", name, 5)) {
 163                         add_extra_have(extra_have, old_sha1);
 164                         continue;
 165                 }
 166
 167                 if (!check_ref(name, name_len, flags))
 168                         continue;
 169                 ref = alloc_ref(buffer + 41);
 170                 hashcpy(ref->old_sha1, old_sha1);
 171                 *list = ref;
 172                 list = &ref->next;
 173                 got_at_least_one_head = 1;
 174         }
 175
 176         annotate_refs_with_symref_info(*orig_list);
 177
 178         return list;
 179 }
 180
 181 static const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
 182 {
 183         int len;
 184
 185         if (!feature_list)
 186                 return NULL;
 187
 188         len = strlen(feature);
 189         while (*feature_list) {
 190                 const char *found = strstr(feature_list, feature);
 191                 if (!found)
 192                         return NULL;
 193                 if (feature_list == found || isspace(found[-1])) {
 194                         const char *value = found + len;
 195                         /* feature with no value (e.g., "thin-pack") */
 196                         if (!*value || isspace(*value)) {
 197                                 if (lenp)
 198                                         *lenp = 0;
 199                                 return value;
 200                         }
 201                         /* feature with a value (e.g., "agent=git/1.2.3") */
 202                         else if (*value == '=') {
 203                                 value++;
 204                                 if (lenp)
 205                                         *lenp = strcspn(value, " \t\n");
 206                                 return value;
 207                         }
 208                         /*
 209                          * otherwise we matched a substring of another feature;
 210                          * keep looking
 211                          */
 212                 }
 213                 feature_list = found + 1;
 214         }
 215         return NULL;
 216 }
 217
 218 int parse_feature_request(const char *feature_list, const char *feature)
 219 {
 220         return !!parse_feature_value(feature_list, feature, NULL);
 221 }
 222
 223 const char *server_feature_value(const char *feature, int *len)
 224 {
 225         return parse_feature_value(server_capabilities, feature, len);
 226 }
 227
 228 int server_supports(const char *feature)
 229 {
 230         return !!server_feature_value(feature, NULL);
 231 }
 232
 233 enum protocol {
 234         PROTO_LOCAL = 1,
 235         PROTO_SSH,
 236         PROTO_GIT
 237 };
 238
 239 static enum protocol get_protocol(const char *name)
 240 {
 241         if (!strcmp(name, "ssh"))
 242                 return PROTO_SSH;
 243         if (!strcmp(name, "git"))
 244                 return PROTO_GIT;
 245         if (!strcmp(name, "git+ssh"))
 246                 return PROTO_SSH;
 247         if (!strcmp(name, "ssh+git"))
 248                 return PROTO_SSH;
 249         if (!strcmp(name, "file"))
 250                 return PROTO_LOCAL;
 251         die("I don't handle protocol '%s'", name);
 252 }
 253
 254 #define STR_(s) # s
 255 #define STR(s)  STR_(s)
 256
 257 static void get_host_and_port(char **host, const char **port)
 258 {
 259         char *colon, *end;
 260
 261         if (*host[0] == '[') {
 262                 end = strchr(*host + 1, ']');
 263                 if (end) {
 264                         *end = 0;
 265                         end++;
 266                         (*host)++;
 267                 } else
 268                         end = *host;
 269         } else
 270                 end = *host;
 271         colon = strchr(end, ':');
 272
 273         if (colon) {
 274                 *colon = 0;
 275                 *port = colon + 1;
 276         }
 277 }
 278
 279 static void enable_keepalive(int sockfd)
 280 {
 281         int ka = 1;
 282
 283         if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
 284                 fprintf(stderr, "unable to set SO_KEEPALIVE on socket: %s\n",
 285                         strerror(errno));
 286 }
 287
 288 #ifndef NO_IPV6
 289
 290 static const char *ai_name(const struct addrinfo *ai)
 291 {
 292         static char addr[NI_MAXHOST];
 293         if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
 294                         NI_NUMERICHOST) != 0)
 295                 strcpy(addr, "(unknown)");
 296
 297         return addr;
 298 }
 299
 300 /*
 301  * Returns a connected socket() fd, or else die()s.
 302  */
 303 static int git_tcp_connect_sock(char *host, int flags)
 304 {
 305         struct strbuf error_message = STRBUF_INIT;
 306         int sockfd = -1;
 307         const char *port = STR(DEFAULT_GIT_PORT);
 308         struct addrinfo hints, *ai0, *ai;
 309         int gai;
 310         int cnt = 0;
 311
 312         get_host_and_port(&host, &port);
 313         if (!*port)
 314                 port = "<none>";
 315
 316         memset(&hints, 0, sizeof(hints));
 317         hints.ai_socktype = SOCK_STREAM;
 318         hints.ai_protocol = IPPROTO_TCP;
 319
 320         if (flags & CONNECT_VERBOSE)
 321                 fprintf(stderr, "Looking up %s ... ", host);
 322
 323         gai = getaddrinfo(host, port, &hints, &ai);
 324         if (gai)
 325                 die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
 326
 327         if (flags & CONNECT_VERBOSE)
 328                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 329
 330         for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
 331                 sockfd = socket(ai->ai_family,
 332                                 ai->ai_socktype, ai->ai_protocol);
 333                 if ((sockfd < 0) ||
 334                     (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
 335                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 336                                     host, cnt, ai_name(ai), strerror(errno));
 337                         if (0 <= sockfd)
 338                                 close(sockfd);
 339                         sockfd = -1;
 340                         continue;
 341                 }
 342                 if (flags & CONNECT_VERBOSE)
 343                         fprintf(stderr, "%s ", ai_name(ai));
 344                 break;
 345         }
 346
 347         freeaddrinfo(ai0);
 348
 349         if (sockfd < 0)
 350                 die("unable to connect to %s:\n%s", host, error_message.buf);
 351
 352         enable_keepalive(sockfd);
 353
 354         if (flags & CONNECT_VERBOSE)
 355                 fprintf(stderr, "done.\n");
 356
 357         strbuf_release(&error_message);
 358
 359         return sockfd;
 360 }
 361
 362 #else /* NO_IPV6 */
 363
 364 /*
 365  * Returns a connected socket() fd, or else die()s.
 366  */
 367 static int git_tcp_connect_sock(char *host, int flags)
 368 {
 369         struct strbuf error_message = STRBUF_INIT;
 370         int sockfd = -1;
 371         const char *port = STR(DEFAULT_GIT_PORT);
 372         char *ep;
 373         struct hostent *he;
 374         struct sockaddr_in sa;
 375         char **ap;
 376         unsigned int nport;
 377         int cnt;
 378
 379         get_host_and_port(&host, &port);
 380
 381         if (flags & CONNECT_VERBOSE)
 382                 fprintf(stderr, "Looking up %s ... ", host);
 383
 384         he = gethostbyname(host);
 385         if (!he)
 386                 die("Unable to look up %s (%s)", host, hstrerror(h_errno));
 387         nport = strtoul(port, &ep, 10);
 388         if ( ep == port || *ep ) {
 389                 /* Not numeric */
 390                 struct servent *se = getservbyname(port,"tcp");
 391                 if ( !se )
 392                         die("Unknown port %s", port);
 393                 nport = se->s_port;
 394         }
 395
 396         if (flags & CONNECT_VERBOSE)
 397                 fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
 398
 399         for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
 400                 memset(&sa, 0, sizeof sa);
 401                 sa.sin_family = he->h_addrtype;
 402                 sa.sin_port = htons(nport);
 403                 memcpy(&sa.sin_addr, *ap, he->h_length);
 404
 405                 sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 406                 if ((sockfd < 0) ||
 407                     connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 408                         strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
 409                                 host,
 410                                 cnt,
 411                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr),
 412                                 strerror(errno));
 413                         if (0 <= sockfd)
 414                                 close(sockfd);
 415                         sockfd = -1;
 416                         continue;
 417                 }
 418                 if (flags & CONNECT_VERBOSE)
 419                         fprintf(stderr, "%s ",
 420                                 inet_ntoa(*(struct in_addr *)&sa.sin_addr));
 421                 break;
 422         }
 423
 424         if (sockfd < 0)
 425                 die("unable to connect to %s:\n%s", host, error_message.buf);
 426
 427         enable_keepalive(sockfd);
 428
 429         if (flags & CONNECT_VERBOSE)
 430                 fprintf(stderr, "done.\n");
 431
 432         return sockfd;
 433 }
 434
 435 #endif /* NO_IPV6 */
 436
 437
 438 static void git_tcp_connect(int fd[2], char *host, int flags)
 439 {
 440         int sockfd = git_tcp_connect_sock(host, flags);
 441
 442         fd[0] = sockfd;
 443         fd[1] = dup(sockfd);
 444 }
 445
 446
 447 static char *git_proxy_command;
 448
 449 static int git_proxy_command_options(const char *var, const char *value,
 450                 void *cb)
 451 {
 452         if (!strcmp(var, "core.gitproxy")) {
 453                 const char *for_pos;
 454                 int matchlen = -1;
 455                 int hostlen;
 456                 const char *rhost_name = cb;
 457                 int rhost_len = strlen(rhost_name);
 458
 459                 if (git_proxy_command)
 460                         return 0;
 461                 if (!value)
 462                         return config_error_nonbool(var);
 463                 /* [core]
 464                  * ;# matches www.kernel.org as well
 465                  * gitproxy = netcatter-1 for kernel.org
 466                  * gitproxy = netcatter-2 for sample.xz
 467                  * gitproxy = netcatter-default
 468                  */
 469                 for_pos = strstr(value, " for ");
 470                 if (!for_pos)
 471                         /* matches everybody */
 472                         matchlen = strlen(value);
 473                 else {
 474                         hostlen = strlen(for_pos + 5);
 475                         if (rhost_len < hostlen)
 476                                 matchlen = -1;
 477                         else if (!strncmp(for_pos + 5,
 478                                           rhost_name + rhost_len - hostlen,
 479                                           hostlen) &&
 480                                  ((rhost_len == hostlen) ||
 481                                   rhost_name[rhost_len - hostlen -1] == '.'))
 482                                 matchlen = for_pos - value;
 483                         else
 484                                 matchlen = -1;
 485                 }
 486                 if (0 <= matchlen) {
 487                         /* core.gitproxy = none for kernel.org */
 488                         if (matchlen == 4 &&
 489                             !memcmp(value, "none", 4))
 490                                 matchlen = 0;
 491                         git_proxy_command = xmemdupz(value, matchlen);
 492                 }
 493                 return 0;
 494         }
 495
 496         return git_default_config(var, value, cb);
 497 }
 498
 499 static int git_use_proxy(const char *host)
 500 {
 501         git_proxy_command = getenv("GIT_PROXY_COMMAND");
 502         git_config(git_proxy_command_options, (void*)host);
 503         return (git_proxy_command && *git_proxy_command);
 504 }
 505
 506 static struct child_process *git_proxy_connect(int fd[2], char *host)
 507 {
 508         const char *port = STR(DEFAULT_GIT_PORT);
 509         const char **argv;
 510         struct child_process *proxy;
 511
 512         get_host_and_port(&host, &port);
 513
 514         argv = xmalloc(sizeof(*argv) * 4);
 515         argv[0] = git_proxy_command;
 516         argv[1] = host;
 517         argv[2] = port;
 518         argv[3] = NULL;
 519         proxy = xcalloc(1, sizeof(*proxy));
 520         proxy->argv = argv;
 521         proxy->in = -1;
 522         proxy->out = -1;
 523         if (start_command(proxy))
 524                 die("cannot start proxy %s", argv[0]);
 525         fd[0] = proxy->out; /* read from proxy stdout */
 526         fd[1] = proxy->in;  /* write to proxy stdin */
 527         return proxy;
 528 }
 529
 530 #define MAX_CMD_LEN 1024
 531
 532 static char *get_port(char *host)
 533 {
 534         char *end;
 535         char *p = strchr(host, ':');
 536
 537         if (p) {
 538                 long port = strtol(p + 1, &end, 10);
 539                 if (end != p + 1 && *end == '\0' && 0 <= port && port < 65536) {
 540                         *p = '\0';
 541                         return p+1;
 542                 }
 543         }
 544
 545         return NULL;
 546 }
 547
 548 static struct child_process no_fork;
 549
 550 /*
 551  * This returns a dummy child_process if the transport protocol does not
 552  * need fork(2), or a struct child_process object if it does.  Once done,
 553  * finish the connection with finish_connect() with the value returned from
 554  * this function (it is safe to call finish_connect() with NULL to support
 555  * the former case).
 556  *
 557  * If it returns, the connect is successful; it just dies on errors (this
 558  * will hopefully be changed in a libification effort, to return NULL when
 559  * the connection failed).
 560  */
 561 struct child_process *git_connect(int fd[2], const char *url_orig,
 562                                   const char *prog, int flags)
 563 {
 564         char *url;
 565         char *host, *path;
 566         char *end;
 567         int c;
 568         struct child_process *conn = &no_fork;
 569         enum protocol protocol = PROTO_LOCAL;
 570         int free_path = 0;
 571         char *port = NULL;
 572         const char **arg;
 573         struct strbuf cmd;
 574
 575         /* Without this we cannot rely on waitpid() to tell
 576          * what happened to our children.
 577          */
 578         signal(SIGCHLD, SIG_DFL);
 579
 580         if (is_url(url_orig))
 581                 url = url_decode(url_orig);
 582         else
 583                 url = xstrdup(url_orig);
 584
 585         host = strstr(url, "://");
 586         if (host) {
 587                 *host = '\0';
 588                 protocol = get_protocol(url);
 589                 host += 3;
 590                 c = '/';
 591         } else {
 592                 host = url;
 593                 c = ':';
 594         }
 595
 596         /*
 597          * Don't do destructive transforms with git:// as that
 598          * protocol code does '[]' unwrapping of its own.
 599          */
 600         if (host[0] == '[') {
 601                 end = strchr(host + 1, ']');
 602                 if (end) {
 603                         if (protocol != PROTO_GIT) {
 604                                 *end = 0;
 605                                 host++;
 606                         }
 607                         end++;
 608                 } else
 609                         end = host;
 610         } else
 611                 end = host;
 612
 613         path = strchr(end, c);
 614         if (path && !has_dos_drive_prefix(end)) {
 615                 if (c == ':') {
 616                         if (host != url || path < strchrnul(host, '/')) {
 617                                 protocol = PROTO_SSH;
 618                                 *path++ = '\0';
 619                         } else /* '/' in the host part, assume local path */
 620                                 path = end;
 621                 }
 622         } else
 623                 path = end;
 624
 625         if (!path || !*path)
 626                 die("No path specified. See 'man git-pull' for valid url syntax");
 627
 628         /*
 629          * null-terminate hostname and point path to ~ for URL's like this:
 630          *    ssh://host.xz/~user/repo
 631          */
 632         if (protocol != PROTO_LOCAL && host != url) {
 633                 char *ptr = path;
 634                 if (path[1] == '~')
 635                         path++;
 636                 else {
 637                         path = xstrdup(ptr);
 638                         free_path = 1;
 639                 }
 640
 641                 *ptr = '\0';
 642         }
 643
 644         /*
 645          * Add support for ssh port: ssh://host.xy:<port>/...
 646          */
 647         if (protocol == PROTO_SSH && host != url)
 648                 port = get_port(end);
 649
 650         if (protocol == PROTO_GIT) {
 651                 /* These underlying connection commands die() if they
 652                  * cannot connect.
 653                  */
 654                 char *target_host = xstrdup(host);
 655                 if (git_use_proxy(host))
 656                         conn = git_proxy_connect(fd, host);
 657                 else
 658                         git_tcp_connect(fd, host, flags);
 659                 /*
 660                  * Separate original protocol components prog and path
 661                  * from extended host header with a NUL byte.
 662                  *
 663                  * Note: Do not add any other headers here!  Doing so
 664                  * will cause older git-daemon servers to crash.
 665                  */
 666                 packet_write(fd[1],
 667                              "%s %s%chost=%s%c",
 668                              prog, path, 0,
 669                              target_host, 0);
 670                 free(target_host);
 671                 free(url);
 672                 if (free_path)
 673                         free(path);
 674                 return conn;
 675         }
 676
 677         conn = xcalloc(1, sizeof(*conn));
 678
 679         strbuf_init(&cmd, MAX_CMD_LEN);
 680         strbuf_addstr(&cmd, prog);
 681         strbuf_addch(&cmd, ' ');
 682         sq_quote_buf(&cmd, path);
 683         if (cmd.len >= MAX_CMD_LEN)
 684                 die("command line too long");
 685
 686         conn->in = conn->out = -1;
 687         conn->argv = arg = xcalloc(7, sizeof(*arg));
 688         if (protocol == PROTO_SSH) {
 689                 const char *ssh = getenv("GIT_SSH");
 690                 int putty = ssh && strcasestr(ssh, "plink");
 691                 if (!ssh) ssh = "ssh";
 692
 693                 *arg++ = ssh;
 694                 if (putty && !strcasestr(ssh, "tortoiseplink"))
 695                         *arg++ = "-batch";
 696                 if (port) {
 697                         /* P is for PuTTY, p is for OpenSSH */
 698                         *arg++ = putty ? "-P" : "-p";
 699                         *arg++ = port;
 700                 }
 701                 *arg++ = host;
 702         }
 703         else {
 704                 /* remove repo-local variables from the environment */
 705                 conn->env = local_repo_env;
 706                 conn->use_shell = 1;
 707         }
 708         *arg++ = cmd.buf;
 709         *arg = NULL;
 710
 711         if (start_command(conn))
 712                 die("unable to fork");
 713
 714         fd[0] = conn->out; /* read from child's stdout */
 715         fd[1] = conn->in;  /* write to child's stdin */
 716         strbuf_release(&cmd);
 717         free(url);
 718         if (free_path)
 719                 free(path);
 720         return conn;
 721 }
 722
 723 int git_connection_is_socket(struct child_process *conn)
 724 {
 725         return conn == &no_fork;
 726 }
 727
 728 int finish_connect(struct child_process *conn)
 729 {
 730         int code;
 731         if (!conn || git_connection_is_socket(conn))
 732                 return 0;
 733
 734         code = finish_command(conn);
 735         free(conn->argv);
 736         free(conn);
 737         return code;
 738 }