daemon.c

   1 #include "cache.h"
   2 #include "pkt-line.h"
   3 #include "exec_cmd.h"
   4 #include "run-command.h"
   5 #include "strbuf.h"
   6 #include "string-list.h"
   7
   8 #ifndef HOST_NAME_MAX
   9 #define HOST_NAME_MAX 256
  10 #endif
  11
  12 #ifdef NO_INITGROUPS
  13 #define initgroups(x, y) (0) /* nothing */
  14 #endif
  15
  16 static int log_syslog;
  17 static int verbose;
  18 static int reuseaddr;
  19 static int informative_errors;
  20
  21 static const char daemon_usage[] =
  22 "git daemon [--verbose] [--syslog] [--export-all]\n"
  23 "           [--timeout=<n>] [--init-timeout=<n>] [--max-connections=<n>]\n"
  24 "           [--strict-paths] [--base-path=<path>] [--base-path-relaxed]\n"
  25 "           [--user-path | --user-path=<path>]\n"
  26 "           [--interpolated-path=<path>]\n"
  27 "           [--reuseaddr] [--pid-file=<file>]\n"
  28 "           [--(enable|disable|allow-override|forbid-override)=<service>]\n"
  29 "           [--access-hook=<path>]\n"
  30 "           [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
  31 "                      [--detach] [--user=<user> [--group=<group>]]\n"
  32 "           [<directory>...]";
  33
  34 /* List of acceptable pathname prefixes */
  35 static char **ok_paths;
  36 static int strict_paths;
  37
  38 /* If this is set, git-daemon-export-ok is not required */
  39 static int export_all_trees;
  40
  41 /* Take all paths relative to this one if non-NULL */
  42 static const char *base_path;
  43 static const char *interpolated_path;
  44 static int base_path_relaxed;
  45
  46 /* Flag indicating client sent extra args. */
  47 static int saw_extended_args;
  48
  49 /* If defined, ~user notation is allowed and the string is inserted
  50  * after ~user/.  E.g. a request to git://host/~alice/frotz would
  51  * go to /home/alice/pub_git/frotz with --user-path=pub_git.
  52  */
  53 static const char *user_path;
  54
  55 /* Timeout, and initial timeout */
  56 static unsigned int timeout;
  57 static unsigned int init_timeout;
  58
  59 static char *hostname;
  60 static char *canon_hostname;
  61 static char *ip_address;
  62 static char *tcp_port;
  63
  64 static void logreport(int priority, const char *err, va_list params)
  65 {
  66         if (log_syslog) {
  67                 char buf[1024];
  68                 vsnprintf(buf, sizeof(buf), err, params);
  69                 syslog(priority, "%s", buf);
  70         } else {
  71                 /*
  72                  * Since stderr is set to buffered mode, the
  73                  * logging of different processes will not overlap
  74                  * unless they overflow the (rather big) buffers.
  75                  */
  76                 fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
  77                 vfprintf(stderr, err, params);
  78                 fputc('\n', stderr);
  79                 fflush(stderr);
  80         }
  81 }
  82
  83 __attribute__((format (printf, 1, 2)))
  84 static void logerror(const char *err, ...)
  85 {
  86         va_list params;
  87         va_start(params, err);
  88         logreport(LOG_ERR, err, params);
  89         va_end(params);
  90 }
  91
  92 __attribute__((format (printf, 1, 2)))
  93 static void loginfo(const char *err, ...)
  94 {
  95         va_list params;
  96         if (!verbose)
  97                 return;
  98         va_start(params, err);
  99         logreport(LOG_INFO, err, params);
 100         va_end(params);
 101 }
 102
 103 static void NORETURN daemon_die(const char *err, va_list params)
 104 {
 105         logreport(LOG_ERR, err, params);
 106         exit(1);
 107 }
 108
 109 static const char *path_ok(const char *directory)
 110 {
 111         static char rpath[PATH_MAX];
 112         static char interp_path[PATH_MAX];
 113         const char *path;
 114         const char *dir;
 115
 116         dir = directory;
 117
 118         if (daemon_avoid_alias(dir)) {
 119                 logerror("'%s': aliased", dir);
 120                 return NULL;
 121         }
 122
 123         if (*dir == '~') {
 124                 if (!user_path) {
 125                         logerror("'%s': User-path not allowed", dir);
 126                         return NULL;
 127                 }
 128                 if (*user_path) {
 129                         /* Got either "~alice" or "~alice/foo";
 130                          * rewrite them to "~alice/%s" or
 131                          * "~alice/%s/foo".
 132                          */
 133                         int namlen, restlen = strlen(dir);
 134                         const char *slash = strchr(dir, '/');
 135                         if (!slash)
 136                                 slash = dir + restlen;
 137                         namlen = slash - dir;
 138                         restlen -= namlen;
 139                         loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
 140                         snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
 141                                  namlen, dir, user_path, restlen, slash);
 142                         dir = rpath;
 143                 }
 144         }
 145         else if (interpolated_path && saw_extended_args) {
 146                 struct strbuf expanded_path = STRBUF_INIT;
 147                 struct strbuf_expand_dict_entry dict[6];
 148
 149                 dict[0].placeholder = "H"; dict[0].value = hostname;
 150                 dict[1].placeholder = "CH"; dict[1].value = canon_hostname;
 151                 dict[2].placeholder = "IP"; dict[2].value = ip_address;
 152                 dict[3].placeholder = "P"; dict[3].value = tcp_port;
 153                 dict[4].placeholder = "D"; dict[4].value = directory;
 154                 dict[5].placeholder = NULL; dict[5].value = NULL;
 155                 if (*dir != '/') {
 156                         /* Allow only absolute */
 157                         logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 158                         return NULL;
 159                 }
 160
 161                 strbuf_expand(&expanded_path, interpolated_path,
 162                                 strbuf_expand_dict_cb, &dict);
 163                 strlcpy(interp_path, expanded_path.buf, PATH_MAX);
 164                 strbuf_release(&expanded_path);
 165                 loginfo("Interpolated dir '%s'", interp_path);
 166
 167                 dir = interp_path;
 168         }
 169         else if (base_path) {
 170                 if (*dir != '/') {
 171                         /* Allow only absolute */
 172                         logerror("'%s': Non-absolute path denied (base-path active)", dir);
 173                         return NULL;
 174                 }
 175                 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
 176                 dir = rpath;
 177         }
 178
 179         path = enter_repo(dir, strict_paths);
 180         if (!path && base_path && base_path_relaxed) {
 181                 /*
 182                  * if we fail and base_path_relaxed is enabled, try without
 183                  * prefixing the base path
 184                  */
 185                 dir = directory;
 186                 path = enter_repo(dir, strict_paths);
 187         }
 188
 189         if (!path) {
 190                 logerror("'%s' does not appear to be a git repository", dir);
 191                 return NULL;
 192         }
 193
 194         if ( ok_paths && *ok_paths ) {
 195                 char **pp;
 196                 int pathlen = strlen(path);
 197
 198                 /* The validation is done on the paths after enter_repo
 199                  * appends optional {.git,.git/.git} and friends, but
 200                  * it does not use getcwd().  So if your /pub is
 201                  * a symlink to /mnt/pub, you can whitelist /pub and
 202                  * do not have to say /mnt/pub.
 203                  * Do not say /pub/.
 204                  */
 205                 for ( pp = ok_paths ; *pp ; pp++ ) {
 206                         int len = strlen(*pp);
 207                         if (len <= pathlen &&
 208                             !memcmp(*pp, path, len) &&
 209                             (path[len] == '\0' ||
 210                              (!strict_paths && path[len] == '/')))
 211                                 return path;
 212                 }
 213         }
 214         else {
 215                 /* be backwards compatible */
 216                 if (!strict_paths)
 217                         return path;
 218         }
 219
 220         logerror("'%s': not in whitelist", path);
 221         return NULL;            /* Fallthrough. Deny by default */
 222 }
 223
 224 typedef int (*daemon_service_fn)(void);
 225 struct daemon_service {
 226         const char *name;
 227         const char *config_name;
 228         daemon_service_fn fn;
 229         int enabled;
 230         int overridable;
 231 };
 232
 233 static struct daemon_service *service_looking_at;
 234 static int service_enabled;
 235
 236 static int git_daemon_config(const char *var, const char *value, void *cb)
 237 {
 238         const char *service;
 239
 240         if (skip_prefix(var, "daemon.", &service) &&
 241             !strcmp(service, service_looking_at->config_name)) {
 242                 service_enabled = git_config_bool(var, value);
 243                 return 0;
 244         }
 245
 246         /* we are not interested in parsing any other configuration here */
 247         return 0;
 248 }
 249
 250 static int daemon_error(const char *dir, const char *msg)
 251 {
 252         if (!informative_errors)
 253                 msg = "access denied or repository not exported";
 254         packet_write(1, "ERR %s: %s", msg, dir);
 255         return -1;
 256 }
 257
 258 static const char *access_hook;
 259
 260 static int run_access_hook(struct daemon_service *service, const char *dir, const char *path)
 261 {
 262         struct child_process child = CHILD_PROCESS_INIT;
 263         struct strbuf buf = STRBUF_INIT;
 264         const char *argv[8];
 265         const char **arg = argv;
 266         char *eol;
 267         int seen_errors = 0;
 268
 269 #define STRARG(x) ((x) ? (x) : "")
 270         *arg++ = access_hook;
 271         *arg++ = service->name;
 272         *arg++ = path;
 273         *arg++ = STRARG(hostname);
 274         *arg++ = STRARG(canon_hostname);
 275         *arg++ = STRARG(ip_address);
 276         *arg++ = STRARG(tcp_port);
 277         *arg = NULL;
 278 #undef STRARG
 279
 280         child.use_shell = 1;
 281         child.argv = argv;
 282         child.no_stdin = 1;
 283         child.no_stderr = 1;
 284         child.out = -1;
 285         if (start_command(&child)) {
 286                 logerror("daemon access hook '%s' failed to start",
 287                          access_hook);
 288                 goto error_return;
 289         }
 290         if (strbuf_read(&buf, child.out, 0) < 0) {
 291                 logerror("failed to read from pipe to daemon access hook '%s'",
 292                          access_hook);
 293                 strbuf_reset(&buf);
 294                 seen_errors = 1;
 295         }
 296         if (close(child.out) < 0) {
 297                 logerror("failed to close pipe to daemon access hook '%s'",
 298                          access_hook);
 299                 seen_errors = 1;
 300         }
 301         if (finish_command(&child))
 302                 seen_errors = 1;
 303
 304         if (!seen_errors) {
 305                 strbuf_release(&buf);
 306                 return 0;
 307         }
 308
 309 error_return:
 310         strbuf_ltrim(&buf);
 311         if (!buf.len)
 312                 strbuf_addstr(&buf, "service rejected");
 313         eol = strchr(buf.buf, '\n');
 314         if (eol)
 315                 *eol = '\0';
 316         errno = EACCES;
 317         daemon_error(dir, buf.buf);
 318         strbuf_release(&buf);
 319         return -1;
 320 }
 321
 322 static int run_service(const char *dir, struct daemon_service *service)
 323 {
 324         const char *path;
 325         int enabled = service->enabled;
 326
 327         loginfo("Request %s for '%s'", service->name, dir);
 328
 329         if (!enabled && !service->overridable) {
 330                 logerror("'%s': service not enabled.", service->name);
 331                 errno = EACCES;
 332                 return daemon_error(dir, "service not enabled");
 333         }
 334
 335         if (!(path = path_ok(dir)))
 336                 return daemon_error(dir, "no such repository");
 337
 338         /*
 339          * Security on the cheap.
 340          *
 341          * We want a readable HEAD, usable "objects" directory, and
 342          * a "git-daemon-export-ok" flag that says that the other side
 343          * is ok with us doing this.
 344          *
 345          * path_ok() uses enter_repo() and does whitelist checking.
 346          * We only need to make sure the repository is exported.
 347          */
 348
 349         if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 350                 logerror("'%s': repository not exported.", path);
 351                 errno = EACCES;
 352                 return daemon_error(dir, "repository not exported");
 353         }
 354
 355         if (service->overridable) {
 356                 service_looking_at = service;
 357                 service_enabled = -1;
 358                 git_config(git_daemon_config, NULL);
 359                 if (0 <= service_enabled)
 360                         enabled = service_enabled;
 361         }
 362         if (!enabled) {
 363                 logerror("'%s': service not enabled for '%s'",
 364                          service->name, path);
 365                 errno = EACCES;
 366                 return daemon_error(dir, "service not enabled");
 367         }
 368
 369         /*
 370          * Optionally, a hook can choose to deny access to the
 371          * repository depending on the phase of the moon.
 372          */
 373         if (access_hook && run_access_hook(service, dir, path))
 374                 return -1;
 375
 376         /*
 377          * We'll ignore SIGTERM from now on, we have a
 378          * good client.
 379          */
 380         signal(SIGTERM, SIG_IGN);
 381
 382         return service->fn();
 383 }
 384
 385 static void copy_to_log(int fd)
 386 {
 387         struct strbuf line = STRBUF_INIT;
 388         FILE *fp;
 389
 390         fp = fdopen(fd, "r");
 391         if (fp == NULL) {
 392                 logerror("fdopen of error channel failed");
 393                 close(fd);
 394                 return;
 395         }
 396
 397         while (strbuf_getline(&line, fp, '\n') != EOF) {
 398                 logerror("%s", line.buf);
 399                 strbuf_setlen(&line, 0);
 400         }
 401
 402         strbuf_release(&line);
 403         fclose(fp);
 404 }
 405
 406 static int run_service_command(const char **argv)
 407 {
 408         struct child_process cld = CHILD_PROCESS_INIT;
 409
 410         cld.argv = argv;
 411         cld.git_cmd = 1;
 412         cld.err = -1;
 413         if (start_command(&cld))
 414                 return -1;
 415
 416         close(0);
 417         close(1);
 418
 419         copy_to_log(cld.err);
 420
 421         return finish_command(&cld);
 422 }
 423
 424 static int upload_pack(void)
 425 {
 426         /* Timeout as string */
 427         char timeout_buf[64];
 428         const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
 429
 430         argv[2] = timeout_buf;
 431
 432         snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 433         return run_service_command(argv);
 434 }
 435
 436 static int upload_archive(void)
 437 {
 438         static const char *argv[] = { "upload-archive", ".", NULL };
 439         return run_service_command(argv);
 440 }
 441
 442 static int receive_pack(void)
 443 {
 444         static const char *argv[] = { "receive-pack", ".", NULL };
 445         return run_service_command(argv);
 446 }
 447
 448 static struct daemon_service daemon_service[] = {
 449         { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 450         { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 451         { "receive-pack", "receivepack", receive_pack, 0, 1 },
 452 };
 453
 454 static void enable_service(const char *name, int ena)
 455 {
 456         int i;
 457         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 458                 if (!strcmp(daemon_service[i].name, name)) {
 459                         daemon_service[i].enabled = ena;
 460                         return;
 461                 }
 462         }
 463         die("No such service %s", name);
 464 }
 465
 466 static void make_service_overridable(const char *name, int ena)
 467 {
 468         int i;
 469         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 470                 if (!strcmp(daemon_service[i].name, name)) {
 471                         daemon_service[i].overridable = ena;
 472                         return;
 473                 }
 474         }
 475         die("No such service %s", name);
 476 }
 477
 478 static void parse_host_and_port(char *hostport, char **host,
 479         char **port)
 480 {
 481         if (*hostport == '[') {
 482                 char *end;
 483
 484                 end = strchr(hostport, ']');
 485                 if (!end)
 486                         die("Invalid request ('[' without ']')");
 487                 *end = '\0';
 488                 *host = hostport + 1;
 489                 if (!end[1])
 490                         *port = NULL;
 491                 else if (end[1] == ':')
 492                         *port = end + 2;
 493                 else
 494                         die("Garbage after end of host part");
 495         } else {
 496                 *host = hostport;
 497                 *port = strrchr(hostport, ':');
 498                 if (*port) {
 499                         **port = '\0';
 500                         ++*port;
 501                 }
 502         }
 503 }
 504
 505 /*
 506  * Read the host as supplied by the client connection.
 507  */
 508 static void parse_host_arg(char *extra_args, int buflen)
 509 {
 510         char *val;
 511         int vallen;
 512         char *end = extra_args + buflen;
 513
 514         if (extra_args < end && *extra_args) {
 515                 saw_extended_args = 1;
 516                 if (strncasecmp("host=", extra_args, 5) == 0) {
 517                         val = extra_args + 5;
 518                         vallen = strlen(val) + 1;
 519                         if (*val) {
 520                                 /* Split <host>:<port> at colon. */
 521                                 char *host;
 522                                 char *port;
 523                                 parse_host_and_port(val, &host, &port);
 524                                 if (port) {
 525                                         free(tcp_port);
 526                                         tcp_port = xstrdup(port);
 527                                 }
 528                                 free(hostname);
 529                                 hostname = xstrdup_tolower(host);
 530                         }
 531
 532                         /* On to the next one */
 533                         extra_args = val + vallen;
 534                 }
 535                 if (extra_args < end && *extra_args)
 536                         die("Invalid request");
 537         }
 538
 539         /*
 540          * Locate canonical hostname and its IP address.
 541          */
 542         if (hostname) {
 543 #ifndef NO_IPV6
 544                 struct addrinfo hints;
 545                 struct addrinfo *ai;
 546                 int gai;
 547                 static char addrbuf[HOST_NAME_MAX + 1];
 548
 549                 memset(&hints, 0, sizeof(hints));
 550                 hints.ai_flags = AI_CANONNAME;
 551
 552                 gai = getaddrinfo(hostname, NULL, &hints, &ai);
 553                 if (!gai) {
 554                         struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 555
 556                         inet_ntop(AF_INET, &sin_addr->sin_addr,
 557                                   addrbuf, sizeof(addrbuf));
 558                         free(ip_address);
 559                         ip_address = xstrdup(addrbuf);
 560
 561                         free(canon_hostname);
 562                         canon_hostname = xstrdup(ai->ai_canonname ?
 563                                                  ai->ai_canonname : ip_address);
 564
 565                         freeaddrinfo(ai);
 566                 }
 567 #else
 568                 struct hostent *hent;
 569                 struct sockaddr_in sa;
 570                 char **ap;
 571                 static char addrbuf[HOST_NAME_MAX + 1];
 572
 573                 hent = gethostbyname(hostname);
 574
 575                 ap = hent->h_addr_list;
 576                 memset(&sa, 0, sizeof sa);
 577                 sa.sin_family = hent->h_addrtype;
 578                 sa.sin_port = htons(0);
 579                 memcpy(&sa.sin_addr, *ap, hent->h_length);
 580
 581                 inet_ntop(hent->h_addrtype, &sa.sin_addr,
 582                           addrbuf, sizeof(addrbuf));
 583
 584                 free(canon_hostname);
 585                 canon_hostname = xstrdup(hent->h_name);
 586                 free(ip_address);
 587                 ip_address = xstrdup(addrbuf);
 588 #endif
 589         }
 590 }
 591
 592
 593 static int execute(void)
 594 {
 595         char *line = packet_buffer;
 596         int pktlen, len, i;
 597         char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
 598
 599         if (addr)
 600                 loginfo("Connection from %s:%s", addr, port);
 601
 602         alarm(init_timeout ? init_timeout : timeout);
 603         pktlen = packet_read(0, NULL, NULL, packet_buffer, sizeof(packet_buffer), 0);
 604         alarm(0);
 605
 606         len = strlen(line);
 607         if (pktlen != len)
 608                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
 609                         (int) pktlen - len,
 610                         (int) pktlen - len, line + len + 1);
 611         if (len && line[len-1] == '\n') {
 612                 line[--len] = 0;
 613                 pktlen--;
 614         }
 615
 616         free(hostname);
 617         free(canon_hostname);
 618         free(ip_address);
 619         free(tcp_port);
 620         hostname = canon_hostname = ip_address = tcp_port = NULL;
 621
 622         if (len != pktlen)
 623                 parse_host_arg(line + len + 1, pktlen - len - 1);
 624
 625         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 626                 struct daemon_service *s = &(daemon_service[i]);
 627                 const char *arg;
 628
 629                 if (skip_prefix(line, "git-", &arg) &&
 630                     skip_prefix(arg, s->name, &arg) &&
 631                     *arg++ == ' ') {
 632                         /*
 633                          * Note: The directory here is probably context sensitive,
 634                          * and might depend on the actual service being performed.
 635                          */
 636                         return run_service(arg, s);
 637                 }
 638         }
 639
 640         logerror("Protocol error: '%s'", line);
 641         return -1;
 642 }
 643
 644 static int addrcmp(const struct sockaddr_storage *s1,
 645     const struct sockaddr_storage *s2)
 646 {
 647         const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 648         const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 649
 650         if (sa1->sa_family != sa2->sa_family)
 651                 return sa1->sa_family - sa2->sa_family;
 652         if (sa1->sa_family == AF_INET)
 653                 return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 654                     &((struct sockaddr_in *)s2)->sin_addr,
 655                     sizeof(struct in_addr));
 656 #ifndef NO_IPV6
 657         if (sa1->sa_family == AF_INET6)
 658                 return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 659                     &((struct sockaddr_in6 *)s2)->sin6_addr,
 660                     sizeof(struct in6_addr));
 661 #endif
 662         return 0;
 663 }
 664
 665 static int max_connections = 32;
 666
 667 static unsigned int live_children;
 668
 669 static struct child {
 670         struct child *next;
 671         struct child_process cld;
 672         struct sockaddr_storage address;
 673 } *firstborn;
 674
 675 static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
 676 {
 677         struct child *newborn, **cradle;
 678
 679         newborn = xcalloc(1, sizeof(*newborn));
 680         live_children++;
 681         memcpy(&newborn->cld, cld, sizeof(*cld));
 682         memcpy(&newborn->address, addr, addrlen);
 683         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 684                 if (!addrcmp(&(*cradle)->address, &newborn->address))
 685                         break;
 686         newborn->next = *cradle;
 687         *cradle = newborn;
 688 }
 689
 690 /*
 691  * This gets called if the number of connections grows
 692  * past "max_connections".
 693  *
 694  * We kill the newest connection from a duplicate IP.
 695  */
 696 static void kill_some_child(void)
 697 {
 698         const struct child *blanket, *next;
 699
 700         if (!(blanket = firstborn))
 701                 return;
 702
 703         for (; (next = blanket->next); blanket = next)
 704                 if (!addrcmp(&blanket->address, &next->address)) {
 705                         kill(blanket->cld.pid, SIGTERM);
 706                         break;
 707                 }
 708 }
 709
 710 static void check_dead_children(void)
 711 {
 712         int status;
 713         pid_t pid;
 714
 715         struct child **cradle, *blanket;
 716         for (cradle = &firstborn; (blanket = *cradle);)
 717                 if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
 718                         const char *dead = "";
 719                         if (status)
 720                                 dead = " (with error)";
 721                         loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 722
 723                         /* remove the child */
 724                         *cradle = blanket->next;
 725                         live_children--;
 726                         free(blanket);
 727                 } else
 728                         cradle = &blanket->next;
 729 }
 730
 731 static char **cld_argv;
 732 static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 733 {
 734         struct child_process cld = CHILD_PROCESS_INIT;
 735         char addrbuf[300] = "REMOTE_ADDR=", portbuf[300];
 736         char *env[] = { addrbuf, portbuf, NULL };
 737
 738         if (max_connections && live_children >= max_connections) {
 739                 kill_some_child();
 740                 sleep(1);  /* give it some time to die */
 741                 check_dead_children();
 742                 if (live_children >= max_connections) {
 743                         close(incoming);
 744                         logerror("Too many children, dropping connection");
 745                         return;
 746                 }
 747         }
 748
 749         if (addr->sa_family == AF_INET) {
 750                 struct sockaddr_in *sin_addr = (void *) addr;
 751                 inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf + 12,
 752                     sizeof(addrbuf) - 12);
 753                 snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 754                     ntohs(sin_addr->sin_port));
 755 #ifndef NO_IPV6
 756         } else if (addr->sa_family == AF_INET6) {
 757                 struct sockaddr_in6 *sin6_addr = (void *) addr;
 758
 759                 char *buf = addrbuf + 12;
 760                 *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 761                 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf,
 762                     sizeof(addrbuf) - 13);
 763                 strcat(buf, "]");
 764
 765                 snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 766                     ntohs(sin6_addr->sin6_port));
 767 #endif
 768         }
 769
 770         cld.env = (const char **)env;
 771         cld.argv = (const char **)cld_argv;
 772         cld.in = incoming;
 773         cld.out = dup(incoming);
 774
 775         if (start_command(&cld))
 776                 logerror("unable to fork");
 777         else
 778                 add_child(&cld, addr, addrlen);
 779 }
 780
 781 static void child_handler(int signo)
 782 {
 783         /*
 784          * Otherwise empty handler because systemcalls will get interrupted
 785          * upon signal receipt
 786          * SysV needs the handler to be rearmed
 787          */
 788         signal(SIGCHLD, child_handler);
 789 }
 790
 791 static int set_reuse_addr(int sockfd)
 792 {
 793         int on = 1;
 794
 795         if (!reuseaddr)
 796                 return 0;
 797         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 798                           &on, sizeof(on));
 799 }
 800
 801 struct socketlist {
 802         int *list;
 803         size_t nr;
 804         size_t alloc;
 805 };
 806
 807 static const char *ip2str(int family, struct sockaddr *sin, socklen_t len)
 808 {
 809 #ifdef NO_IPV6
 810         static char ip[INET_ADDRSTRLEN];
 811 #else
 812         static char ip[INET6_ADDRSTRLEN];
 813 #endif
 814
 815         switch (family) {
 816 #ifndef NO_IPV6
 817         case AF_INET6:
 818                 inet_ntop(family, &((struct sockaddr_in6*)sin)->sin6_addr, ip, len);
 819                 break;
 820 #endif
 821         case AF_INET:
 822                 inet_ntop(family, &((struct sockaddr_in*)sin)->sin_addr, ip, len);
 823                 break;
 824         default:
 825                 strcpy(ip, "<unknown>");
 826         }
 827         return ip;
 828 }
 829
 830 #ifndef NO_IPV6
 831
 832 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 833 {
 834         int socknum = 0;
 835         int maxfd = -1;
 836         char pbuf[NI_MAXSERV];
 837         struct addrinfo hints, *ai0, *ai;
 838         int gai;
 839         long flags;
 840
 841         sprintf(pbuf, "%d", listen_port);
 842         memset(&hints, 0, sizeof(hints));
 843         hints.ai_family = AF_UNSPEC;
 844         hints.ai_socktype = SOCK_STREAM;
 845         hints.ai_protocol = IPPROTO_TCP;
 846         hints.ai_flags = AI_PASSIVE;
 847
 848         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 849         if (gai) {
 850                 logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
 851                 return 0;
 852         }
 853
 854         for (ai = ai0; ai; ai = ai->ai_next) {
 855                 int sockfd;
 856
 857                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 858                 if (sockfd < 0)
 859                         continue;
 860                 if (sockfd >= FD_SETSIZE) {
 861                         logerror("Socket descriptor too large");
 862                         close(sockfd);
 863                         continue;
 864                 }
 865
 866 #ifdef IPV6_V6ONLY
 867                 if (ai->ai_family == AF_INET6) {
 868                         int on = 1;
 869                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 870                                    &on, sizeof(on));
 871                         /* Note: error is not fatal */
 872                 }
 873 #endif
 874
 875                 if (set_reuse_addr(sockfd)) {
 876                         logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 877                         close(sockfd);
 878                         continue;
 879                 }
 880
 881                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 882                         logerror("Could not bind to %s: %s",
 883                                  ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 884                                  strerror(errno));
 885                         close(sockfd);
 886                         continue;       /* not fatal */
 887                 }
 888                 if (listen(sockfd, 5) < 0) {
 889                         logerror("Could not listen to %s: %s",
 890                                  ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 891                                  strerror(errno));
 892                         close(sockfd);
 893                         continue;       /* not fatal */
 894                 }
 895
 896                 flags = fcntl(sockfd, F_GETFD, 0);
 897                 if (flags >= 0)
 898                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 899
 900                 ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 901                 socklist->list[socklist->nr++] = sockfd;
 902                 socknum++;
 903
 904                 if (maxfd < sockfd)
 905                         maxfd = sockfd;
 906         }
 907
 908         freeaddrinfo(ai0);
 909
 910         return socknum;
 911 }
 912
 913 #else /* NO_IPV6 */
 914
 915 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 916 {
 917         struct sockaddr_in sin;
 918         int sockfd;
 919         long flags;
 920
 921         memset(&sin, 0, sizeof sin);
 922         sin.sin_family = AF_INET;
 923         sin.sin_port = htons(listen_port);
 924
 925         if (listen_addr) {
 926                 /* Well, host better be an IP address here. */
 927                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 928                         return 0;
 929         } else {
 930                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
 931         }
 932
 933         sockfd = socket(AF_INET, SOCK_STREAM, 0);
 934         if (sockfd < 0)
 935                 return 0;
 936
 937         if (set_reuse_addr(sockfd)) {
 938                 logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 939                 close(sockfd);
 940                 return 0;
 941         }
 942
 943         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 944                 logerror("Could not listen to %s: %s",
 945                          ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
 946                          strerror(errno));
 947                 close(sockfd);
 948                 return 0;
 949         }
 950
 951         if (listen(sockfd, 5) < 0) {
 952                 logerror("Could not listen to %s: %s",
 953                          ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
 954                          strerror(errno));
 955                 close(sockfd);
 956                 return 0;
 957         }
 958
 959         flags = fcntl(sockfd, F_GETFD, 0);
 960         if (flags >= 0)
 961                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 962
 963         ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 964         socklist->list[socklist->nr++] = sockfd;
 965         return 1;
 966 }
 967
 968 #endif
 969
 970 static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
 971 {
 972         if (!listen_addr->nr)
 973                 setup_named_sock(NULL, listen_port, socklist);
 974         else {
 975                 int i, socknum;
 976                 for (i = 0; i < listen_addr->nr; i++) {
 977                         socknum = setup_named_sock(listen_addr->items[i].string,
 978                                                    listen_port, socklist);
 979
 980                         if (socknum == 0)
 981                                 logerror("unable to allocate any listen sockets for host %s on port %u",
 982                                          listen_addr->items[i].string, listen_port);
 983                 }
 984         }
 985 }
 986
 987 static int service_loop(struct socketlist *socklist)
 988 {
 989         struct pollfd *pfd;
 990         int i;
 991
 992         pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
 993
 994         for (i = 0; i < socklist->nr; i++) {
 995                 pfd[i].fd = socklist->list[i];
 996                 pfd[i].events = POLLIN;
 997         }
 998
 999         signal(SIGCHLD, child_handler);
1000
1001         for (;;) {
1002                 int i;
1003
1004                 check_dead_children();
1005
1006                 if (poll(pfd, socklist->nr, -1) < 0) {
1007                         if (errno != EINTR) {
1008                                 logerror("Poll failed, resuming: %s",
1009                                       strerror(errno));
1010                                 sleep(1);
1011                         }
1012                         continue;
1013                 }
1014
1015                 for (i = 0; i < socklist->nr; i++) {
1016                         if (pfd[i].revents & POLLIN) {
1017                                 union {
1018                                         struct sockaddr sa;
1019                                         struct sockaddr_in sai;
1020 #ifndef NO_IPV6
1021                                         struct sockaddr_in6 sai6;
1022 #endif
1023                                 } ss;
1024                                 socklen_t sslen = sizeof(ss);
1025                                 int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
1026                                 if (incoming < 0) {
1027                                         switch (errno) {
1028                                         case EAGAIN:
1029                                         case EINTR:
1030                                         case ECONNABORTED:
1031                                                 continue;
1032                                         default:
1033                                                 die_errno("accept returned");
1034                                         }
1035                                 }
1036                                 handle(incoming, &ss.sa, sslen);
1037                         }
1038                 }
1039         }
1040 }
1041
1042 #ifdef NO_POSIX_GOODIES
1043
1044 struct credentials;
1045
1046 static void drop_privileges(struct credentials *cred)
1047 {
1048         /* nothing */
1049 }
1050
1051 static struct credentials *prepare_credentials(const char *user_name,
1052     const char *group_name)
1053 {
1054         die("--user not supported on this platform");
1055 }
1056
1057 #else
1058
1059 struct credentials {
1060         struct passwd *pass;
1061         gid_t gid;
1062 };
1063
1064 static void drop_privileges(struct credentials *cred)
1065 {
1066         if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
1067             setgid (cred->gid) || setuid(cred->pass->pw_uid)))
1068                 die("cannot drop privileges");
1069 }
1070
1071 static struct credentials *prepare_credentials(const char *user_name,
1072     const char *group_name)
1073 {
1074         static struct credentials c;
1075
1076         c.pass = getpwnam(user_name);
1077         if (!c.pass)
1078                 die("user not found - %s", user_name);
1079
1080         if (!group_name)
1081                 c.gid = c.pass->pw_gid;
1082         else {
1083                 struct group *group = getgrnam(group_name);
1084                 if (!group)
1085                         die("group not found - %s", group_name);
1086
1087                 c.gid = group->gr_gid;
1088         }
1089
1090         return &c;
1091 }
1092 #endif
1093
1094 static void store_pid(const char *path)
1095 {
1096         FILE *f = fopen(path, "w");
1097         if (!f)
1098                 die_errno("cannot open pid file '%s'", path);
1099         if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
1100                 die_errno("failed to write pid file '%s'", path);
1101 }
1102
1103 static int serve(struct string_list *listen_addr, int listen_port,
1104     struct credentials *cred)
1105 {
1106         struct socketlist socklist = { NULL, 0, 0 };
1107
1108         socksetup(listen_addr, listen_port, &socklist);
1109         if (socklist.nr == 0)
1110                 die("unable to allocate any listen sockets on port %u",
1111                     listen_port);
1112
1113         drop_privileges(cred);
1114
1115         loginfo("Ready to rumble");
1116
1117         return service_loop(&socklist);
1118 }
1119
1120 int main(int argc, char **argv)
1121 {
1122         int listen_port = 0;
1123         struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1124         int serve_mode = 0, inetd_mode = 0;
1125         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1126         int detach = 0;
1127         struct credentials *cred = NULL;
1128         int i;
1129
1130         git_setup_gettext();
1131
1132         git_extract_argv0_path(argv[0]);
1133
1134         for (i = 1; i < argc; i++) {
1135                 char *arg = argv[i];
1136                 const char *v;
1137
1138                 if (skip_prefix(arg, "--listen=", &v)) {
1139                         string_list_append(&listen_addr, xstrdup_tolower(v));
1140                         continue;
1141                 }
1142                 if (skip_prefix(arg, "--port=", &v)) {
1143                         char *end;
1144                         unsigned long n;
1145                         n = strtoul(v, &end, 0);
1146                         if (*v && !*end) {
1147                                 listen_port = n;
1148                                 continue;
1149                         }
1150                 }
1151                 if (!strcmp(arg, "--serve")) {
1152                         serve_mode = 1;
1153                         continue;
1154                 }
1155                 if (!strcmp(arg, "--inetd")) {
1156                         inetd_mode = 1;
1157                         log_syslog = 1;
1158                         continue;
1159                 }
1160                 if (!strcmp(arg, "--verbose")) {
1161                         verbose = 1;
1162                         continue;
1163                 }
1164                 if (!strcmp(arg, "--syslog")) {
1165                         log_syslog = 1;
1166                         continue;
1167                 }
1168                 if (!strcmp(arg, "--export-all")) {
1169                         export_all_trees = 1;
1170                         continue;
1171                 }
1172                 if (skip_prefix(arg, "--access-hook=", &v)) {
1173                         access_hook = v;
1174                         continue;
1175                 }
1176                 if (skip_prefix(arg, "--timeout=", &v)) {
1177                         timeout = atoi(v);
1178                         continue;
1179                 }
1180                 if (skip_prefix(arg, "--init-timeout=", &v)) {
1181                         init_timeout = atoi(v);
1182                         continue;
1183                 }
1184                 if (skip_prefix(arg, "--max-connections=", &v)) {
1185                         max_connections = atoi(v);
1186                         if (max_connections < 0)
1187                                 max_connections = 0;            /* unlimited */
1188                         continue;
1189                 }
1190                 if (!strcmp(arg, "--strict-paths")) {
1191                         strict_paths = 1;
1192                         continue;
1193                 }
1194                 if (skip_prefix(arg, "--base-path=", &v)) {
1195                         base_path = v;
1196                         continue;
1197                 }
1198                 if (!strcmp(arg, "--base-path-relaxed")) {
1199                         base_path_relaxed = 1;
1200                         continue;
1201                 }
1202                 if (skip_prefix(arg, "--interpolated-path=", &v)) {
1203                         interpolated_path = v;
1204                         continue;
1205                 }
1206                 if (!strcmp(arg, "--reuseaddr")) {
1207                         reuseaddr = 1;
1208                         continue;
1209                 }
1210                 if (!strcmp(arg, "--user-path")) {
1211                         user_path = "";
1212                         continue;
1213                 }
1214                 if (skip_prefix(arg, "--user-path=", &v)) {
1215                         user_path = v;
1216                         continue;
1217                 }
1218                 if (skip_prefix(arg, "--pid-file=", &v)) {
1219                         pid_file = v;
1220                         continue;
1221                 }
1222                 if (!strcmp(arg, "--detach")) {
1223                         detach = 1;
1224                         log_syslog = 1;
1225                         continue;
1226                 }
1227                 if (skip_prefix(arg, "--user=", &v)) {
1228                         user_name = v;
1229                         continue;
1230                 }
1231                 if (skip_prefix(arg, "--group=", &v)) {
1232                         group_name = v;
1233                         continue;
1234                 }
1235                 if (skip_prefix(arg, "--enable=", &v)) {
1236                         enable_service(v, 1);
1237                         continue;
1238                 }
1239                 if (skip_prefix(arg, "--disable=", &v)) {
1240                         enable_service(v, 0);
1241                         continue;
1242                 }
1243                 if (skip_prefix(arg, "--allow-override=", &v)) {
1244                         make_service_overridable(v, 1);
1245                         continue;
1246                 }
1247                 if (skip_prefix(arg, "--forbid-override=", &v)) {
1248                         make_service_overridable(v, 0);
1249                         continue;
1250                 }
1251                 if (!strcmp(arg, "--informative-errors")) {
1252                         informative_errors = 1;
1253                         continue;
1254                 }
1255                 if (!strcmp(arg, "--no-informative-errors")) {
1256                         informative_errors = 0;
1257                         continue;
1258                 }
1259                 if (!strcmp(arg, "--")) {
1260                         ok_paths = &argv[i+1];
1261                         break;
1262                 } else if (arg[0] != '-') {
1263                         ok_paths = &argv[i];
1264                         break;
1265                 }
1266
1267                 usage(daemon_usage);
1268         }
1269
1270         if (log_syslog) {
1271                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1272                 set_die_routine(daemon_die);
1273         } else
1274                 /* avoid splitting a message in the middle */
1275                 setvbuf(stderr, NULL, _IOFBF, 4096);
1276
1277         if (inetd_mode && (detach || group_name || user_name))
1278                 die("--detach, --user and --group are incompatible with --inetd");
1279
1280         if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1281                 die("--listen= and --port= are incompatible with --inetd");
1282         else if (listen_port == 0)
1283                 listen_port = DEFAULT_GIT_PORT;
1284
1285         if (group_name && !user_name)
1286                 die("--group supplied without --user");
1287
1288         if (user_name)
1289                 cred = prepare_credentials(user_name, group_name);
1290
1291         if (strict_paths && (!ok_paths || !*ok_paths))
1292                 die("option --strict-paths requires a whitelist");
1293
1294         if (base_path && !is_directory(base_path))
1295                 die("base-path '%s' does not exist or is not a directory",
1296                     base_path);
1297
1298         if (inetd_mode) {
1299                 if (!freopen("/dev/null", "w", stderr))
1300                         die_errno("failed to redirect stderr to /dev/null");
1301         }
1302
1303         if (inetd_mode || serve_mode)
1304                 return execute();
1305
1306         if (detach) {
1307                 if (daemonize())
1308                         die("--detach not supported on this platform");
1309         } else
1310                 sanitize_stdfds();
1311
1312         if (pid_file)
1313                 store_pid(pid_file);
1314
1315         /* prepare argv for serving-processes */
1316         cld_argv = xmalloc(sizeof (char *) * (argc + 2));
1317         cld_argv[0] = argv[0];  /* git-daemon */
1318         cld_argv[1] = "--serve";
1319         for (i = 1; i < argc; ++i)
1320                 cld_argv[i+1] = argv[i];
1321         cld_argv[argc+1] = NULL;
1322
1323         return serve(&listen_addr, listen_port, cred);
1324 }