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;
  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 > 45 || 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_ref_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 /*
  44  * Read all the refs from the other end
  45  */
  46 struct ref **get_remote_heads(int in, struct ref **list,
  47                               int nr_match, char **match,
  48                               unsigned int flags)
  49 {
  50         *list = NULL;
  51         for (;;) {
  52                 struct ref *ref;
  53                 unsigned char old_sha1[20];
  54                 static char buffer[1000];
  55                 char *name;
  56                 int len, name_len;
  57
  58                 len = packet_read_line(in, buffer, sizeof(buffer));
  59                 if (!len)
  60                         break;
  61                 if (buffer[len-1] == '\n')
  62                         buffer[--len] = 0;
  63
  64                 if (len < 42 || get_sha1_hex(buffer, old_sha1) || buffer[40] != ' ')
  65                         die("protocol error: expected sha/ref, got '%s'", buffer);
  66                 name = buffer + 41;
  67
  68                 name_len = strlen(name);
  69                 if (len != name_len + 41) {
  70                         if (server_capabilities)
  71                                 free(server_capabilities);
  72                         server_capabilities = strdup(name + name_len + 1);
  73                 }
  74
  75                 if (!check_ref(name, name_len, flags))
  76                         continue;
  77                 if (nr_match && !path_match(name, nr_match, match))
  78                         continue;
  79                 ref = xcalloc(1, sizeof(*ref) + len - 40);
  80                 memcpy(ref->old_sha1, old_sha1, 20);
  81                 memcpy(ref->name, buffer + 41, len - 40);
  82                 *list = ref;
  83                 list = &ref->next;
  84         }
  85         return list;
  86 }
  87
  88 int server_supports(const char *feature)
  89 {
  90         return server_capabilities &&
  91                 strstr(server_capabilities, feature) != NULL;
  92 }
  93
  94 int get_ack(int fd, unsigned char *result_sha1)
  95 {
  96         static char line[1000];
  97         int len = packet_read_line(fd, line, sizeof(line));
  98
  99         if (!len)
 100                 die("git-fetch-pack: expected ACK/NAK, got EOF");
 101         if (line[len-1] == '\n')
 102                 line[--len] = 0;
 103         if (!strcmp(line, "NAK"))
 104                 return 0;
 105         if (!strncmp(line, "ACK ", 4)) {
 106                 if (!get_sha1_hex(line+4, result_sha1)) {
 107                         if (strstr(line+45, "continue"))
 108                                 return 2;
 109                         return 1;
 110                 }
 111         }
 112         die("git-fetch_pack: expected ACK/NAK, got '%s'", line);
 113 }
 114
 115 int path_match(const char *path, int nr, char **match)
 116 {
 117         int i;
 118         int pathlen = strlen(path);
 119
 120         for (i = 0; i < nr; i++) {
 121                 char *s = match[i];
 122                 int len = strlen(s);
 123
 124                 if (!len || len > pathlen)
 125                         continue;
 126                 if (memcmp(path + pathlen - len, s, len))
 127                         continue;
 128                 if (pathlen > len && path[pathlen - len - 1] != '/')
 129                         continue;
 130                 *s = 0;
 131                 return (i + 1);
 132         }
 133         return 0;
 134 }
 135
 136 struct refspec {
 137         char *src;
 138         char *dst;
 139         char force;
 140 };
 141
 142 /*
 143  * A:B means fast forward remote B with local A.
 144  * +A:B means overwrite remote B with local A.
 145  * +A is a shorthand for +A:A.
 146  * A is a shorthand for A:A.
 147  */
 148 static struct refspec *parse_ref_spec(int nr_refspec, char **refspec)
 149 {
 150         int i;
 151         struct refspec *rs = xcalloc(sizeof(*rs), (nr_refspec + 1));
 152         for (i = 0; i < nr_refspec; i++) {
 153                 char *sp, *dp, *ep;
 154                 sp = refspec[i];
 155                 if (*sp == '+') {
 156                         rs[i].force = 1;
 157                         sp++;
 158                 }
 159                 ep = strchr(sp, ':');
 160                 if (ep) {
 161                         dp = ep + 1;
 162                         *ep = 0;
 163                 }
 164                 else
 165                         dp = sp;
 166                 rs[i].src = sp;
 167                 rs[i].dst = dp;
 168         }
 169         rs[nr_refspec].src = rs[nr_refspec].dst = NULL;
 170         return rs;
 171 }
 172
 173 static int count_refspec_match(const char *pattern,
 174                                struct ref *refs,
 175                                struct ref **matched_ref)
 176 {
 177         int match;
 178         int patlen = strlen(pattern);
 179
 180         for (match = 0; refs; refs = refs->next) {
 181                 char *name = refs->name;
 182                 int namelen = strlen(name);
 183                 if (namelen < patlen ||
 184                     memcmp(name + namelen - patlen, pattern, patlen))
 185                         continue;
 186                 if (namelen != patlen && name[namelen - patlen - 1] != '/')
 187                         continue;
 188                 match++;
 189                 *matched_ref = refs;
 190         }
 191         return match;
 192 }
 193
 194 static void link_dst_tail(struct ref *ref, struct ref ***tail)
 195 {
 196         **tail = ref;
 197         *tail = &ref->next;
 198         **tail = NULL;
 199 }
 200
 201 static struct ref *try_explicit_object_name(const char *name)
 202 {
 203         unsigned char sha1[20];
 204         struct ref *ref;
 205         int len;
 206         if (get_sha1(name, sha1))
 207                 return NULL;
 208         len = strlen(name) + 1;
 209         ref = xcalloc(1, sizeof(*ref) + len);
 210         memcpy(ref->name, name, len);
 211         memcpy(ref->new_sha1, sha1, 20);
 212         return ref;
 213 }
 214
 215 static int match_explicit_refs(struct ref *src, struct ref *dst,
 216                                struct ref ***dst_tail, struct refspec *rs)
 217 {
 218         int i, errs;
 219         for (i = errs = 0; rs[i].src; i++) {
 220                 struct ref *matched_src, *matched_dst;
 221
 222                 matched_src = matched_dst = NULL;
 223                 switch (count_refspec_match(rs[i].src, src, &matched_src)) {
 224                 case 1:
 225                         break;
 226                 case 0:
 227                         /* The source could be in the get_sha1() format
 228                          * not a reference name.
 229                          */
 230                         matched_src = try_explicit_object_name(rs[i].src);
 231                         if (matched_src)
 232                                 break;
 233                         errs = 1;
 234                         error("src refspec %s does not match any.",
 235                               rs[i].src);
 236                         break;
 237                 default:
 238                         errs = 1;
 239                         error("src refspec %s matches more than one.",
 240                               rs[i].src);
 241                         break;
 242                 }
 243                 switch (count_refspec_match(rs[i].dst, dst, &matched_dst)) {
 244                 case 1:
 245                         break;
 246                 case 0:
 247                         if (!memcmp(rs[i].dst, "refs/", 5)) {
 248                                 int len = strlen(rs[i].dst) + 1;
 249                                 matched_dst = xcalloc(1, sizeof(*dst) + len);
 250                                 memcpy(matched_dst->name, rs[i].dst, len);
 251                                 link_dst_tail(matched_dst, dst_tail);
 252                         }
 253                         else if (!strcmp(rs[i].src, rs[i].dst) &&
 254                                  matched_src) {
 255                                 /* pushing "master:master" when
 256                                  * remote does not have master yet.
 257                                  */
 258                                 int len = strlen(matched_src->name) + 1;
 259                                 matched_dst = xcalloc(1, sizeof(*dst) + len);
 260                                 memcpy(matched_dst->name, matched_src->name,
 261                                        len);
 262                                 link_dst_tail(matched_dst, dst_tail);
 263                         }
 264                         else {
 265                                 errs = 1;
 266                                 error("dst refspec %s does not match any "
 267                                       "existing ref on the remote and does "
 268                                       "not start with refs/.", rs[i].dst);
 269                         }
 270                         break;
 271                 default:
 272                         errs = 1;
 273                         error("dst refspec %s matches more than one.",
 274                               rs[i].dst);
 275                         break;
 276                 }
 277                 if (errs)
 278                         continue;
 279                 if (matched_dst->peer_ref) {
 280                         errs = 1;
 281                         error("dst ref %s receives from more than one src.",
 282                               matched_dst->name);
 283                 }
 284                 else {
 285                         matched_dst->peer_ref = matched_src;
 286                         matched_dst->force = rs[i].force;
 287                 }
 288         }
 289         return -errs;
 290 }
 291
 292 static struct ref *find_ref_by_name(struct ref *list, const char *name)
 293 {
 294         for ( ; list; list = list->next)
 295                 if (!strcmp(list->name, name))
 296                         return list;
 297         return NULL;
 298 }
 299
 300 int match_refs(struct ref *src, struct ref *dst, struct ref ***dst_tail,
 301                int nr_refspec, char **refspec, int all)
 302 {
 303         struct refspec *rs = parse_ref_spec(nr_refspec, refspec);
 304
 305         if (nr_refspec)
 306                 return match_explicit_refs(src, dst, dst_tail, rs);
 307
 308         /* pick the remainder */
 309         for ( ; src; src = src->next) {
 310                 struct ref *dst_peer;
 311                 if (src->peer_ref)
 312                         continue;
 313                 dst_peer = find_ref_by_name(dst, src->name);
 314                 if ((dst_peer && dst_peer->peer_ref) || (!dst_peer && !all))
 315                         continue;
 316                 if (!dst_peer) {
 317                         /* Create a new one and link it */
 318                         int len = strlen(src->name) + 1;
 319                         dst_peer = xcalloc(1, sizeof(*dst_peer) + len);
 320                         memcpy(dst_peer->name, src->name, len);
 321                         memcpy(dst_peer->new_sha1, src->new_sha1, 20);
 322                         link_dst_tail(dst_peer, dst_tail);
 323                 }
 324                 dst_peer->peer_ref = src;
 325         }
 326         return 0;
 327 }
 328
 329 enum protocol {
 330         PROTO_LOCAL = 1,
 331         PROTO_SSH,
 332         PROTO_GIT,
 333 };
 334
 335 static enum protocol get_protocol(const char *name)
 336 {
 337         if (!strcmp(name, "ssh"))
 338                 return PROTO_SSH;
 339         if (!strcmp(name, "git"))
 340                 return PROTO_GIT;
 341         if (!strcmp(name, "git+ssh"))
 342                 return PROTO_SSH;
 343         if (!strcmp(name, "ssh+git"))
 344                 return PROTO_SSH;
 345         die("I don't handle protocol '%s'", name);
 346 }
 347
 348 #define STR_(s) # s
 349 #define STR(s)  STR_(s)
 350
 351 #ifndef NO_IPV6
 352
 353 /*
 354  * Returns a connected socket() fd, or else die()s.
 355  */
 356 static int git_tcp_connect_sock(char *host)
 357 {
 358         int sockfd = -1, saved_errno = 0;
 359         char *colon, *end;
 360         const char *port = STR(DEFAULT_GIT_PORT);
 361         struct addrinfo hints, *ai0, *ai;
 362         int gai;
 363
 364         if (host[0] == '[') {
 365                 end = strchr(host + 1, ']');
 366                 if (end) {
 367                         *end = 0;
 368                         end++;
 369                         host++;
 370                 } else
 371                         end = host;
 372         } else
 373                 end = host;
 374         colon = strchr(end, ':');
 375
 376         if (colon) {
 377                 *colon = 0;
 378                 port = colon + 1;
 379         }
 380
 381         memset(&hints, 0, sizeof(hints));
 382         hints.ai_socktype = SOCK_STREAM;
 383         hints.ai_protocol = IPPROTO_TCP;
 384
 385         gai = getaddrinfo(host, port, &hints, &ai);
 386         if (gai)
 387                 die("Unable to look up %s (%s)", host, gai_strerror(gai));
 388
 389         for (ai0 = ai; ai; ai = ai->ai_next) {
 390                 sockfd = socket(ai->ai_family,
 391                                 ai->ai_socktype, ai->ai_protocol);
 392                 if (sockfd < 0) {
 393                         saved_errno = errno;
 394                         continue;
 395                 }
 396                 if (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 397                         saved_errno = errno;
 398                         close(sockfd);
 399                         sockfd = -1;
 400                         continue;
 401                 }
 402                 break;
 403         }
 404
 405         freeaddrinfo(ai0);
 406
 407         if (sockfd < 0)
 408                 die("unable to connect a socket (%s)", strerror(saved_errno));
 409
 410         return sockfd;
 411 }
 412
 413 #else /* NO_IPV6 */
 414
 415 /*
 416  * Returns a connected socket() fd, or else die()s.
 417  */
 418 static int git_tcp_connect_sock(char *host)
 419 {
 420         int sockfd = -1, saved_errno = 0;
 421         char *colon, *end;
 422         char *port = STR(DEFAULT_GIT_PORT), *ep;
 423         struct hostent *he;
 424         struct sockaddr_in sa;
 425         char **ap;
 426         unsigned int nport;
 427
 428         if (host[0] == '[') {
 429                 end = strchr(host + 1, ']');
 430                 if (end) {
 431                         *end = 0;
 432                         end++;
 433                         host++;
 434                 } else
 435                         end = host;
 436         } else
 437                 end = host;
 438         colon = strchr(end, ':');
 439
 440         if (colon) {
 441                 *colon = 0;
 442                 port = colon + 1;
 443         }
 444
 445         he = gethostbyname(host);
 446         if (!he)
 447                 die("Unable to look up %s (%s)", host, hstrerror(h_errno));
 448         nport = strtoul(port, &ep, 10);
 449         if ( ep == port || *ep ) {
 450                 /* Not numeric */
 451                 struct servent *se = getservbyname(port,"tcp");
 452                 if ( !se )
 453                         die("Unknown port %s\n", port);
 454                 nport = se->s_port;
 455         }
 456
 457         for (ap = he->h_addr_list; *ap; ap++) {
 458                 sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
 459                 if (sockfd < 0) {
 460                         saved_errno = errno;
 461                         continue;
 462                 }
 463
 464                 memset(&sa, 0, sizeof sa);
 465                 sa.sin_family = he->h_addrtype;
 466                 sa.sin_port = htons(nport);
 467                 memcpy(&sa.sin_addr, *ap, he->h_length);
 468
 469                 if (connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
 470                         saved_errno = errno;
 471                         close(sockfd);
 472                         sockfd = -1;
 473                         continue;
 474                 }
 475                 break;
 476         }
 477
 478         if (sockfd < 0)
 479                 die("unable to connect a socket (%s)", strerror(saved_errno));
 480
 481         return sockfd;
 482 }
 483
 484 #endif /* NO_IPV6 */
 485
 486
 487 static void git_tcp_connect(int fd[2], char *host)
 488 {
 489         int sockfd = git_tcp_connect_sock(host);
 490
 491         fd[0] = sockfd;
 492         fd[1] = sockfd;
 493 }
 494
 495
 496 static char *git_proxy_command;
 497 static const char *rhost_name;
 498 static int rhost_len;
 499
 500 static int git_proxy_command_options(const char *var, const char *value)
 501 {
 502         if (!strcmp(var, "core.gitproxy")) {
 503                 const char *for_pos;
 504                 int matchlen = -1;
 505                 int hostlen;
 506
 507                 if (git_proxy_command)
 508                         return 0;
 509                 /* [core]
 510                  * ;# matches www.kernel.org as well
 511                  * gitproxy = netcatter-1 for kernel.org
 512                  * gitproxy = netcatter-2 for sample.xz
 513                  * gitproxy = netcatter-default
 514                  */
 515                 for_pos = strstr(value, " for ");
 516                 if (!for_pos)
 517                         /* matches everybody */
 518                         matchlen = strlen(value);
 519                 else {
 520                         hostlen = strlen(for_pos + 5);
 521                         if (rhost_len < hostlen)
 522                                 matchlen = -1;
 523                         else if (!strncmp(for_pos + 5,
 524                                           rhost_name + rhost_len - hostlen,
 525                                           hostlen) &&
 526                                  ((rhost_len == hostlen) ||
 527                                   rhost_name[rhost_len - hostlen -1] == '.'))
 528                                 matchlen = for_pos - value;
 529                         else
 530                                 matchlen = -1;
 531                 }
 532                 if (0 <= matchlen) {
 533                         /* core.gitproxy = none for kernel.org */
 534                         if (matchlen == 4 &&
 535                             !memcmp(value, "none", 4))
 536                                 matchlen = 0;
 537                         git_proxy_command = xmalloc(matchlen + 1);
 538                         memcpy(git_proxy_command, value, matchlen);
 539                         git_proxy_command[matchlen] = 0;
 540                 }
 541                 return 0;
 542         }
 543
 544         return git_default_config(var, value);
 545 }
 546
 547 static int git_use_proxy(const char *host)
 548 {
 549         rhost_name = host;
 550         rhost_len = strlen(host);
 551         git_proxy_command = getenv("GIT_PROXY_COMMAND");
 552         git_config(git_proxy_command_options);
 553         rhost_name = NULL;
 554         return (git_proxy_command && *git_proxy_command);
 555 }
 556
 557 static void git_proxy_connect(int fd[2], char *host)
 558 {
 559         const char *port = STR(DEFAULT_GIT_PORT);
 560         char *colon, *end;
 561         int pipefd[2][2];
 562         pid_t pid;
 563
 564         if (host[0] == '[') {
 565                 end = strchr(host + 1, ']');
 566                 if (end) {
 567                         *end = 0;
 568                         end++;
 569                         host++;
 570                 } else
 571                         end = host;
 572         } else
 573                 end = host;
 574         colon = strchr(end, ':');
 575
 576         if (colon) {
 577                 *colon = 0;
 578                 port = colon + 1;
 579         }
 580
 581         if (pipe(pipefd[0]) < 0 || pipe(pipefd[1]) < 0)
 582                 die("unable to create pipe pair for communication");
 583         pid = fork();
 584         if (!pid) {
 585                 dup2(pipefd[1][0], 0);
 586                 dup2(pipefd[0][1], 1);
 587                 close(pipefd[0][0]);
 588                 close(pipefd[0][1]);
 589                 close(pipefd[1][0]);
 590                 close(pipefd[1][1]);
 591                 execlp(git_proxy_command, git_proxy_command, host, port, NULL);
 592                 die("exec failed");
 593         }
 594         if (pid < 0)
 595                 die("fork failed");
 596         fd[0] = pipefd[0][0];
 597         fd[1] = pipefd[1][1];
 598         close(pipefd[0][1]);
 599         close(pipefd[1][0]);
 600 }
 601
 602 /*
 603  * Yeah, yeah, fixme. Need to pass in the heads etc.
 604  */
 605 int git_connect(int fd[2], char *url, const char *prog)
 606 {
 607         char command[1024];
 608         char *host, *path = url;
 609         char *end;
 610         int c;
 611         int pipefd[2][2];
 612         pid_t pid;
 613         enum protocol protocol = PROTO_LOCAL;
 614         int free_path = 0;
 615
 616         /* Without this we cannot rely on waitpid() to tell
 617          * what happened to our children.
 618          */
 619         signal(SIGCHLD, SIG_DFL);
 620
 621         host = strstr(url, "://");
 622         if(host) {
 623                 *host = '\0';
 624                 protocol = get_protocol(url);
 625                 host += 3;
 626                 c = '/';
 627         } else {
 628                 host = url;
 629                 c = ':';
 630         }
 631
 632         if (host[0] == '[') {
 633                 end = strchr(host + 1, ']');
 634                 if (end) {
 635                         *end = 0;
 636                         end++;
 637                         host++;
 638                 } else
 639                         end = host;
 640         } else
 641                 end = host;
 642
 643         path = strchr(end, c);
 644         if (c == ':') {
 645                 if (path) {
 646                         protocol = PROTO_SSH;
 647                         *path++ = '\0';
 648                 } else
 649                         path = host;
 650         }
 651
 652         if (!path || !*path)
 653                 die("No path specified. See 'man git-pull' for valid url syntax");
 654
 655         /*
 656          * null-terminate hostname and point path to ~ for URL's like this:
 657          *    ssh://host.xz/~user/repo
 658          */
 659         if (protocol != PROTO_LOCAL && host != url) {
 660                 char *ptr = path;
 661                 if (path[1] == '~')
 662                         path++;
 663                 else {
 664                         path = strdup(ptr);
 665                         free_path = 1;
 666                 }
 667
 668                 *ptr = '\0';
 669         }
 670
 671         if (protocol == PROTO_GIT) {
 672                 /* These underlying connection commands die() if they
 673                  * cannot connect.
 674                  */
 675                 char *target_host = strdup(host);
 676                 if (git_use_proxy(host))
 677                         git_proxy_connect(fd, host);
 678                 else
 679                         git_tcp_connect(fd, host);
 680                 /*
 681                  * Separate original protocol components prog and path
 682                  * from extended components with a NUL byte.
 683                  */
 684                 packet_write(fd[1],
 685                              "%s %s%chost=%s%c",
 686                              prog, path, 0,
 687                              target_host, 0);
 688                 free(target_host);
 689                 if (free_path)
 690                         free(path);
 691                 return 0;
 692         }
 693
 694         if (pipe(pipefd[0]) < 0 || pipe(pipefd[1]) < 0)
 695                 die("unable to create pipe pair for communication");
 696         pid = fork();
 697         if (pid < 0)
 698                 die("unable to fork");
 699         if (!pid) {
 700                 snprintf(command, sizeof(command), "%s %s", prog,
 701                          sq_quote(path));
 702                 dup2(pipefd[1][0], 0);
 703                 dup2(pipefd[0][1], 1);
 704                 close(pipefd[0][0]);
 705                 close(pipefd[0][1]);
 706                 close(pipefd[1][0]);
 707                 close(pipefd[1][1]);
 708                 if (protocol == PROTO_SSH) {
 709                         const char *ssh, *ssh_basename;
 710                         ssh = getenv("GIT_SSH");
 711                         if (!ssh) ssh = "ssh";
 712                         ssh_basename = strrchr(ssh, '/');
 713                         if (!ssh_basename)
 714                                 ssh_basename = ssh;
 715                         else
 716                                 ssh_basename++;
 717                         execlp(ssh, ssh_basename, host, command, NULL);
 718                 }
 719                 else {
 720                         unsetenv(ALTERNATE_DB_ENVIRONMENT);
 721                         unsetenv(DB_ENVIRONMENT);
 722                         unsetenv(GIT_DIR_ENVIRONMENT);
 723                         unsetenv(GRAFT_ENVIRONMENT);
 724                         unsetenv(INDEX_ENVIRONMENT);
 725                         execlp("sh", "sh", "-c", command, NULL);
 726                 }
 727                 die("exec failed");
 728         }
 729         fd[0] = pipefd[0][0];
 730         fd[1] = pipefd[1][1];
 731         close(pipefd[0][1]);
 732         close(pipefd[1][0]);
 733         if (free_path)
 734                 free(path);
 735         return pid;
 736 }
 737
 738 int finish_connect(pid_t pid)
 739 {
 740         while (waitpid(pid, NULL, 0) < 0) {
 741                 if (errno != EINTR)
 742                         return -1;
 743         }
 744         return 0;
 745 }