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 <sys/wait.h>
   7 #include <sys/socket.h>
   8 #include <netinet/in.h>
   9 #include <arpa/inet.h>
  10 #include <netdb.h>
  11 #include <signal.h>
  12
  13 static char *server_capabilities = NULL;
  14
  15 /*
  16  * Read all the refs from the other end
  17  */
  18 struct ref **get_remote_heads(int in, struct ref **list,
  19                               int nr_match, char **match, int ignore_funny)
  20 {
  21         *list = NULL;
  22         for (;;) {
  23                 struct ref *ref;
  24                 unsigned char old_sha1[20];
  25                 static char buffer[1000];
  26                 char *name;
  27                 int len, name_len;
  28
  29                 len = packet_read_line(in, buffer, sizeof(buffer));
  30                 if (!len)
  31                         break;
  32                 if (buffer[len-1] == '\n')
  33                         buffer[--len] = 0;
  34
  35                 if (len < 42 || get_sha1_hex(buffer, old_sha1) || buffer[40] != ' ')
  36                         die("protocol error: expected sha/ref, got '%s'", buffer);
  37                 name = buffer + 41;
  38
  39                 name_len = strlen(name);
  40                 if (len != name_len + 41) {
  41                         if (server_capabilities)
  42                                 free(server_capabilities);
  43                         server_capabilities = strdup(name + name_len + 1);
  44                 }
  45
  46                 if (ignore_funny && 45 < len && !memcmp(name, "refs/", 5) &&
  47                     check_ref_format(name + 5))
  48                         continue;
  49
  50                 if (nr_match && !path_match(name, nr_match, match))
  51                         continue;
  52                 ref = xcalloc(1, sizeof(*ref) + len - 40);
  53                 memcpy(ref->old_sha1, old_sha1, 20);
  54                 memcpy(ref->name, buffer + 41, len - 40);
  55                 *list = ref;
  56                 list = &ref->next;
  57         }
  58         return list;
  59 }
  60
  61 int server_supports(const char *feature)
  62 {
  63         return server_capabilities &&
  64                 strstr(server_capabilities, feature) != NULL;
  65 }
  66
  67 int get_ack(int fd, unsigned char *result_sha1)
  68 {
  69         static char line[1000];
  70         int len = packet_read_line(fd, line, sizeof(line));
  71
  72         if (!len)
  73                 die("git-fetch-pack: expected ACK/NAK, got EOF");
  74         if (line[len-1] == '\n')
  75                 line[--len] = 0;
  76         if (!strcmp(line, "NAK"))
  77                 return 0;
  78         if (!strncmp(line, "ACK ", 4)) {
  79                 if (!get_sha1_hex(line+4, result_sha1)) {
  80                         if (strstr(line+45, "continue"))
  81                                 return 2;
  82                         return 1;
  83                 }
  84         }
  85         die("git-fetch_pack: expected ACK/NAK, got '%s'", line);
  86 }
  87
  88 int path_match(const char *path, int nr, char **match)
  89 {
  90         int i;
  91         int pathlen = strlen(path);
  92
  93         for (i = 0; i < nr; i++) {
  94                 char *s = match[i];
  95                 int len = strlen(s);
  96
  97                 if (!len || len > pathlen)
  98                         continue;
  99                 if (memcmp(path + pathlen - len, s, len))
 100                         continue;
 101                 if (pathlen > len && path[pathlen - len - 1] != '/')
 102                         continue;
 103                 *s = 0;
 104                 return (i + 1);
 105         }
 106         return 0;
 107 }
 108
 109 struct refspec {
 110         char *src;
 111         char *dst;
 112         char force;
 113 };
 114
 115 /*
 116  * A:B means fast forward remote B with local A.
 117  * +A:B means overwrite remote B with local A.
 118  * +A is a shorthand for +A:A.
 119  * A is a shorthand for A:A.
 120  */
 121 static struct refspec *parse_ref_spec(int nr_refspec, char **refspec)
 122 {
 123         int i;
 124         struct refspec *rs = xcalloc(sizeof(*rs), (nr_refspec + 1));
 125         for (i = 0; i < nr_refspec; i++) {
 126                 char *sp, *dp, *ep;
 127                 sp = refspec[i];
 128                 if (*sp == '+') {
 129                         rs[i].force = 1;
 130                         sp++;
 131                 }
 132                 ep = strchr(sp, ':');
 133                 if (ep) {
 134                         dp = ep + 1;
 135                         *ep = 0;
 136                 }
 137                 else
 138                         dp = sp;
 139                 rs[i].src = sp;
 140                 rs[i].dst = dp;
 141         }
 142         rs[nr_refspec].src = rs[nr_refspec].dst = NULL;
 143         return rs;
 144 }
 145
 146 static int count_refspec_match(const char *pattern,
 147                                struct ref *refs,
 148                                struct ref **matched_ref)
 149 {
 150         int match;
 151         int patlen = strlen(pattern);
 152
 153         for (match = 0; refs; refs = refs->next) {
 154                 char *name = refs->name;
 155                 int namelen = strlen(name);
 156                 if (namelen < patlen ||
 157                     memcmp(name + namelen - patlen, pattern, patlen))
 158                         continue;
 159                 if (namelen != patlen && name[namelen - patlen - 1] != '/')
 160                         continue;
 161                 match++;
 162                 *matched_ref = refs;
 163         }
 164         return match;
 165 }
 166
 167 static void link_dst_tail(struct ref *ref, struct ref ***tail)
 168 {
 169         **tail = ref;
 170         *tail = &ref->next;
 171         **tail = NULL;
 172 }
 173
 174 static struct ref *try_explicit_object_name(const char *name)
 175 {
 176         unsigned char sha1[20];
 177         struct ref *ref;
 178         int len;
 179         if (get_sha1(name, sha1))
 180                 return NULL;
 181         len = strlen(name) + 1;
 182         ref = xcalloc(1, sizeof(*ref) + len);
 183         memcpy(ref->name, name, len);
 184         memcpy(ref->new_sha1, sha1, 20);
 185         return ref;
 186 }
 187
 188 static int match_explicit_refs(struct ref *src, struct ref *dst,
 189                                struct ref ***dst_tail, struct refspec *rs)
 190 {
 191         int i, errs;
 192         for (i = errs = 0; rs[i].src; i++) {
 193                 struct ref *matched_src, *matched_dst;
 194
 195                 matched_src = matched_dst = NULL;
 196                 switch (count_refspec_match(rs[i].src, src, &matched_src)) {
 197                 case 1:
 198                         break;
 199                 case 0:
 200                         /* The source could be in the get_sha1() format
 201                          * not a reference name.
 202                          */
 203                         matched_src = try_explicit_object_name(rs[i].src);
 204                         if (matched_src)
 205                                 break;
 206                         errs = 1;
 207                         error("src refspec %s does not match any.",
 208                               rs[i].src);
 209                         break;
 210                 default:
 211                         errs = 1;
 212                         error("src refspec %s matches more than one.",
 213                               rs[i].src);
 214                         break;
 215                 }
 216                 switch (count_refspec_match(rs[i].dst, dst, &matched_dst)) {
 217                 case 1:
 218                         break;
 219                 case 0:
 220                         if (!memcmp(rs[i].dst, "refs/", 5)) {
 221                                 int len = strlen(rs[i].dst) + 1;
 222                                 matched_dst = xcalloc(1, sizeof(*dst) + len);
 223                                 memcpy(matched_dst->name, rs[i].dst, len);
 224                                 link_dst_tail(matched_dst, dst_tail);
 225                         }
 226                         else if (!strcmp(rs[i].src, rs[i].dst) &&
 227                                  matched_src) {
 228                                 /* pushing "master:master" when
 229                                  * remote does not have master yet.
 230                                  */
 231                                 int len = strlen(matched_src->name) + 1;
 232                                 matched_dst = xcalloc(1, sizeof(*dst) + len);
 233                                 memcpy(matched_dst->name, matched_src->name,
 234                                        len);
 235                                 link_dst_tail(matched_dst, dst_tail);
 236                         }
 237                         else {
 238                                 errs = 1;
 239                                 error("dst refspec %s does not match any "
 240                                       "existing ref on the remote and does "
 241                                       "not start with refs/.", rs[i].dst);
 242                         }
 243                         break;
 244                 default:
 245                         errs = 1;
 246                         error("dst refspec %s matches more than one.",
 247                               rs[i].dst);
 248                         break;
 249                 }
 250                 if (errs)
 251                         continue;
 252                 if (matched_dst->peer_ref) {
 253                         errs = 1;
 254                         error("dst ref %s receives from more than one src.",
 255                               matched_dst->name);
 256                 }
 257                 else {
 258                         matched_dst->peer_ref = matched_src;
 259                         matched_dst->force = rs[i].force;
 260                 }
 261         }
 262         return -errs;
 263 }
 264
 265 static struct ref *find_ref_by_name(struct ref *list, const char *name)
 266 {
 267         for ( ; list; list = list->next)
 268                 if (!strcmp(list->name, name))
 269                         return list;
 270         return NULL;
 271 }
 272
 273 int match_refs(struct ref *src, struct ref *dst, struct ref ***dst_tail,
 274                int nr_refspec, char **refspec, int all)
 275 {
 276         struct refspec *rs = parse_ref_spec(nr_refspec, refspec);
 277
 278         if (nr_refspec)
 279                 return match_explicit_refs(src, dst, dst_tail, rs);
 280
 281         /* pick the remainder */
 282         for ( ; src; src = src->next) {
 283                 struct ref *dst_peer;
 284                 if (src->peer_ref)
 285                         continue;
 286                 dst_peer = find_ref_by_name(dst, src->name);
 287                 if ((dst_peer && dst_peer->peer_ref) || (!dst_peer && !all))
 288                         continue;
 289                 if (!dst_peer) {
 290                         /* Create a new one and link it */
 291                         int len = strlen(src->name) + 1;
 292                         dst_peer = xcalloc(1, sizeof(*dst_peer) + len);
 293                         memcpy(dst_peer->name, src->name, len);
 294                         memcpy(dst_peer->new_sha1, src->new_sha1, 20);
 295                         link_dst_tail(dst_peer, dst_tail);
 296                 }
 297                 dst_peer->peer_ref = src;
 298         }
 299         return 0;
 300 }
 301
 302 enum protocol {
 303         PROTO_LOCAL = 1,
 304         PROTO_SSH,
 305         PROTO_GIT,
 306 };
 307
 308 static enum protocol get_protocol(const char *name)
 309 {
 310         if (!strcmp(name, "ssh"))
 311                 return PROTO_SSH;
 312         if (!strcmp(name, "git"))
 313                 return PROTO_GIT;
 314         if (!strcmp(name, "git+ssh"))
 315                 return PROTO_SSH;
 316         if (!strcmp(name, "ssh+git"))
 317                 return PROTO_SSH;
 318         die("I don't handle protocol '%s'", name);
 319 }
 320
 321 #define STR_(s) # s
 322 #define STR(s)  STR_(s)
 323
 324 #ifndef NO_IPV6
 325
 326 /*
 327  * Returns a connected socket() fd, or else die()s.
 328  */
 329 static int git_tcp_connect_sock(char *host)
 330 {
 331         int sockfd = -1, saved_errno = 0;
 332         char *colon, *end;
 333         const char *port = STR(DEFAULT_GIT_PORT);
 334         struct addrinfo hints, *ai0, *ai;
 335         int gai;
 336
 337         if (host[0] == '[') {
 338                 end = strchr(host + 1, ']');
 339                 if (end) {
 340                         *end = 0;
 341                         end++;
 342                         host++;
 343                 } else
 344                         end = host;
 345         } else
 346                 end = host;
 347         colon = strchr(end, ':');
 348
 349         if (colon) {
 350                 *colon = 0;
 351                 port = colon + 1;
 352         }
 353
 354         memset(&hints, 0, sizeof(hints));
 355         hints.ai_socktype = SOCK_STREAM;
 356         hints.ai_protocol = IPPROTO_TCP;
 357
 358         gai = getaddrinfo(host, port, &hints, &ai);
 359         if (gai)
 360                 die("Unable to look up %s (%s)", host, gai_strerror(gai));
 361
 362         for (ai0 = ai; ai; ai = ai->ai_next) {
 363                 sockfd = socket(ai->ai_family,
 364                                 ai->ai_socktype, ai->ai_protocol);
 365                 if (sockfd < 0) {
 366                         saved_errno = errno;
 367                         continue;
 368                 }
 369                 if (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 370                         saved_errno = errno;
 371                         close(sockfd);
 372                         sockfd = -1;
 373                         continue;
 374                 }
 375                 break;
 376         }
 377
 378         freeaddrinfo(ai0);
 379
 380         if (sockfd < 0)
 381                 die("unable to connect a socket (%s)", strerror(saved_errno));
 382
 383         return sockfd;
 384 }
 385
 386 #else /* NO_IPV6 */
 387
 388 /*
 389  * Returns a connected socket() fd, or else die()s.
 390  */
 391 static int git_tcp_connect_sock(char *host)
 392 {
 393         int sockfd = -1, saved_errno = 0;
 394         char *colon, *end;
 395         char *port = STR(DEFAULT_GIT_PORT), *ep;
 396         struct hostent *he;
 397         struct sockaddr_in sa;
 398         char **ap;
 399         unsigned int nport;
 400
 401         if (host[0] == '[') {
 402                 end = strchr(host + 1, ']');
 403                 if (end) {
 404                         *end = 0;
 405                         end++;
 406                         host++;
 407                 } else
 408                         end = host;
 409         } else
 410                 end = host;
 411         colon = strchr(end, ':');
 412
 413         if (colon) {
 414                 *colon = 0;
 415                 port = colon + 1;
 416         }
 417
 418         he = gethostbyname(host);
 419         if (!he)
 420                 die("Unable to look up %s (%s)", host, hstrerror(h_errno));
 421         nport = strtoul(port, &ep, 10);
 422         if ( ep == port || *ep ) {
 423                 /* Not numeric */
 424                 struct servent *se = getservbyname(port,"tcp");
 425                 if ( !se )
 426                         die("Unknown port %s\n", port);
 427                 nport = se->s_port;
 428         }
 429
 430         for (ap = he->h_addr_list; *ap; ap++) {
 431                 sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 432                 if (sockfd < 0) {
 433                         saved_errno = errno;
 434                         continue;
 435                 }
 436
 437                 memset(&sa, 0, sizeof sa);
 438                 sa.sin_family = he->h_addrtype;
 439                 sa.sin_port = htons(nport);
 440                 memcpy(&sa.sin_addr, *ap, he->h_length);
 441
 442                 if (connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 443                         saved_errno = errno;
 444                         close(sockfd);
 445                         sockfd = -1;
 446                         continue;
 447                 }
 448                 break;
 449         }
 450
 451         if (sockfd < 0)
 452                 die("unable to connect a socket (%s)", strerror(saved_errno));
 453
 454         return sockfd;
 455 }
 456
 457 #endif /* NO_IPV6 */
 458
 459
 460 static void git_tcp_connect(int fd[2], char *host)
 461 {
 462         int sockfd = git_tcp_connect_sock(host);
 463
 464         fd[0] = sockfd;
 465         fd[1] = sockfd;
 466 }
 467
 468
 469 static char *git_proxy_command = NULL;
 470 static const char *rhost_name = NULL;
 471 static int rhost_len;
 472
 473 static int git_proxy_command_options(const char *var, const char *value)
 474 {
 475         if (!strcmp(var, "core.gitproxy")) {
 476                 const char *for_pos;
 477                 int matchlen = -1;
 478                 int hostlen;
 479
 480                 if (git_proxy_command)
 481                         return 0;
 482                 /* [core]
 483                  * ;# matches www.kernel.org as well
 484                  * gitproxy = netcatter-1 for kernel.org
 485                  * gitproxy = netcatter-2 for sample.xz
 486                  * gitproxy = netcatter-default
 487                  */
 488                 for_pos = strstr(value, " for ");
 489                 if (!for_pos)
 490                         /* matches everybody */
 491                         matchlen = strlen(value);
 492                 else {
 493                         hostlen = strlen(for_pos + 5);
 494                         if (rhost_len < hostlen)
 495                                 matchlen = -1;
 496                         else if (!strncmp(for_pos + 5,
 497                                           rhost_name + rhost_len - hostlen,
 498                                           hostlen) &&
 499                                  ((rhost_len == hostlen) ||
 500                                   rhost_name[rhost_len - hostlen -1] == '.'))
 501                                 matchlen = for_pos - value;
 502                         else
 503                                 matchlen = -1;
 504                 }
 505                 if (0 <= matchlen) {
 506                         /* core.gitproxy = none for kernel.org */
 507                         if (matchlen == 4 &&
 508                             !memcmp(value, "none", 4))
 509                                 matchlen = 0;
 510                         git_proxy_command = xmalloc(matchlen + 1);
 511                         memcpy(git_proxy_command, value, matchlen);
 512                         git_proxy_command[matchlen] = 0;
 513                 }
 514                 return 0;
 515         }
 516
 517         return git_default_config(var, value);
 518 }
 519
 520 static int git_use_proxy(const char *host)
 521 {
 522         rhost_name = host;
 523         rhost_len = strlen(host);
 524         git_proxy_command = getenv("GIT_PROXY_COMMAND");
 525         git_config(git_proxy_command_options);
 526         rhost_name = NULL;
 527         return (git_proxy_command && *git_proxy_command);
 528 }
 529
 530 static void git_proxy_connect(int fd[2], char *host)
 531 {
 532         const char *port = STR(DEFAULT_GIT_PORT);
 533         char *colon, *end;
 534         int pipefd[2][2];
 535         pid_t pid;
 536
 537         if (host[0] == '[') {
 538                 end = strchr(host + 1, ']');
 539                 if (end) {
 540                         *end = 0;
 541                         end++;
 542                         host++;
 543                 } else
 544                         end = host;
 545         } else
 546                 end = host;
 547         colon = strchr(end, ':');
 548
 549         if (colon) {
 550                 *colon = 0;
 551                 port = colon + 1;
 552         }
 553
 554         if (pipe(pipefd[0]) < 0 || pipe(pipefd[1]) < 0)
 555                 die("unable to create pipe pair for communication");
 556         pid = fork();
 557         if (!pid) {
 558                 dup2(pipefd[1][0], 0);
 559                 dup2(pipefd[0][1], 1);
 560                 close(pipefd[0][0]);
 561                 close(pipefd[0][1]);
 562                 close(pipefd[1][0]);
 563                 close(pipefd[1][1]);
 564                 execlp(git_proxy_command, git_proxy_command, host, port, NULL);
 565                 die("exec failed");
 566         }
 567         if (pid < 0)
 568                 die("fork failed");
 569         fd[0] = pipefd[0][0];
 570         fd[1] = pipefd[1][1];
 571         close(pipefd[0][1]);
 572         close(pipefd[1][0]);
 573 }
 574
 575 /*
 576  * Yeah, yeah, fixme. Need to pass in the heads etc.
 577  */
 578 int git_connect(int fd[2], char *url, const char *prog)
 579 {
 580         char command[1024];
 581         char *host, *path = url;
 582         char *end;
 583         int c;
 584         int pipefd[2][2];
 585         pid_t pid;
 586         enum protocol protocol = PROTO_LOCAL;
 587         int free_path = 0;
 588
 589         /* Without this we cannot rely on waitpid() to tell
 590          * what happened to our children.
 591          */
 592         signal(SIGCHLD, SIG_DFL);
 593
 594         host = strstr(url, "://");
 595         if(host) {
 596                 *host = '\0';
 597                 protocol = get_protocol(url);
 598                 host += 3;
 599                 c = '/';
 600         } else {
 601                 host = url;
 602                 c = ':';
 603         }
 604
 605         if (host[0] == '[') {
 606                 end = strchr(host + 1, ']');
 607                 if (end) {
 608                         *end = 0;
 609                         end++;
 610                         host++;
 611                 } else
 612                         end = host;
 613         } else
 614                 end = host;
 615
 616         path = strchr(end, c);
 617         if (c == ':') {
 618                 if (path) {
 619                         protocol = PROTO_SSH;
 620                         *path++ = '\0';
 621                 } else
 622                         path = host;
 623         }
 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 = strdup(ptr);
 638                         free_path = 1;
 639                 }
 640
 641                 *ptr = '\0';
 642         }
 643
 644         if (protocol == PROTO_GIT) {
 645                 /* These underlying connection commands die() if they
 646                  * cannot connect.
 647                  */
 648                 char *target_host = strdup(host);
 649                 if (git_use_proxy(host))
 650                         git_proxy_connect(fd, host);
 651                 else
 652                         git_tcp_connect(fd, host);
 653                 /*
 654                  * Separate original protocol components prog and path
 655                  * from extended components with a NUL byte.
 656                  */
 657                 packet_write(fd[1],
 658                              "%s %s%chost=%s%c",
 659                              prog, path, 0,
 660                              target_host, 0);
 661                 free(target_host);
 662                 if (free_path)
 663                         free(path);
 664                 return 0;
 665         }
 666
 667         if (pipe(pipefd[0]) < 0 || pipe(pipefd[1]) < 0)
 668                 die("unable to create pipe pair for communication");
 669         pid = fork();
 670         if (pid < 0)
 671                 die("unable to fork");
 672         if (!pid) {
 673                 snprintf(command, sizeof(command), "%s %s", prog,
 674                          sq_quote(path));
 675                 dup2(pipefd[1][0], 0);
 676                 dup2(pipefd[0][1], 1);
 677                 close(pipefd[0][0]);
 678                 close(pipefd[0][1]);
 679                 close(pipefd[1][0]);
 680                 close(pipefd[1][1]);
 681                 if (protocol == PROTO_SSH) {
 682                         const char *ssh, *ssh_basename;
 683                         ssh = getenv("GIT_SSH");
 684                         if (!ssh) ssh = "ssh";
 685                         ssh_basename = strrchr(ssh, '/');
 686                         if (!ssh_basename)
 687                                 ssh_basename = ssh;
 688                         else
 689                                 ssh_basename++;
 690                         execlp(ssh, ssh_basename, host, command, NULL);
 691                 }
 692                 else {
 693                         unsetenv(ALTERNATE_DB_ENVIRONMENT);
 694                         unsetenv(DB_ENVIRONMENT);
 695                         unsetenv(GIT_DIR_ENVIRONMENT);
 696                         unsetenv(GRAFT_ENVIRONMENT);
 697                         unsetenv(INDEX_ENVIRONMENT);
 698                         execlp("sh", "sh", "-c", command, NULL);
 699                 }
 700                 die("exec failed");
 701         }
 702         fd[0] = pipefd[0][0];
 703         fd[1] = pipefd[1][1];
 704         close(pipefd[0][1]);
 705         close(pipefd[1][0]);
 706         if (free_path)
 707                 free(path);
 708         return pid;
 709 }
 710
 711 int finish_connect(pid_t pid)
 712 {
 713         int ret;
 714
 715         for (;;) {
 716                 ret = waitpid(pid, NULL, 0);
 717                 if (!ret)
 718                         break;
 719                 if (errno != EINTR)
 720                         break;
 721         }
 722         return ret;
 723 }