git.oblomov.eu Git - git/blob - daemon.c

   1 #include "cache.h"
   2 #include "config.h"
   3 #include "pkt-line.h"
   4 #include "run-command.h"
   5 #include "strbuf.h"
   6 #include "string-list.h"
   7
   8 #ifdef NO_INITGROUPS
   9 #define initgroups(x, y) (0) /* nothing */
  10 #endif
  11
  12 static enum log_destination {
  13         LOG_DESTINATION_UNSET = -1,
  14         LOG_DESTINATION_NONE = 0,
  15         LOG_DESTINATION_STDERR = 1,
  16         LOG_DESTINATION_SYSLOG = 2,
  17 } log_destination = LOG_DESTINATION_UNSET;
  18 static int verbose;
  19 static int reuseaddr;
  20 static int informative_errors;
  21
  22 static const char daemon_usage[] =
  23 "git daemon [--verbose] [--syslog] [--export-all]\n"
  24 "           [--timeout=<n>] [--init-timeout=<n>] [--max-connections=<n>]\n"
  25 "           [--strict-paths] [--base-path=<path>] [--base-path-relaxed]\n"
  26 "           [--user-path | --user-path=<path>]\n"
  27 "           [--interpolated-path=<path>]\n"
  28 "           [--reuseaddr] [--pid-file=<file>]\n"
  29 "           [--(enable|disable|allow-override|forbid-override)=<service>]\n"
  30 "           [--access-hook=<path>]\n"
  31 "           [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
  32 "                      [--detach] [--user=<user> [--group=<group>]]\n"
  33 "           [--log-destination=(stderr|syslog|none)]\n"
  34 "           [<directory>...]";
  35
  36 /* List of acceptable pathname prefixes */
  37 static const char **ok_paths;
  38 static int strict_paths;
  39
  40 /* If this is set, git-daemon-export-ok is not required */
  41 static int export_all_trees;
  42
  43 /* Take all paths relative to this one if non-NULL */
  44 static const char *base_path;
  45 static const char *interpolated_path;
  46 static int base_path_relaxed;
  47
  48 /* If defined, ~user notation is allowed and the string is inserted
  49  * after ~user/.  E.g. a request to git://host/~alice/frotz would
  50  * go to /home/alice/pub_git/frotz with --user-path=pub_git.
  51  */
  52 static const char *user_path;
  53
  54 /* Timeout, and initial timeout */
  55 static unsigned int timeout;
  56 static unsigned int init_timeout;
  57
  58 struct hostinfo {
  59         struct strbuf hostname;
  60         struct strbuf canon_hostname;
  61         struct strbuf ip_address;
  62         struct strbuf tcp_port;
  63         unsigned int hostname_lookup_done:1;
  64         unsigned int saw_extended_args:1;
  65 };
  66
  67 static void lookup_hostname(struct hostinfo *hi);
  68
  69 static const char *get_canon_hostname(struct hostinfo *hi)
  70 {
  71         lookup_hostname(hi);
  72         return hi->canon_hostname.buf;
  73 }
  74
  75 static const char *get_ip_address(struct hostinfo *hi)
  76 {
  77         lookup_hostname(hi);
  78         return hi->ip_address.buf;
  79 }
  80
  81 static void logreport(int priority, const char *err, va_list params)
  82 {
  83         switch (log_destination) {
  84         case LOG_DESTINATION_SYSLOG: {
  85                 char buf[1024];
  86                 vsnprintf(buf, sizeof(buf), err, params);
  87                 syslog(priority, "%s", buf);
  88                 break;
  89         }
  90         case LOG_DESTINATION_STDERR:
  91                 /*
  92                  * Since stderr is set to buffered mode, the
  93                  * logging of different processes will not overlap
  94                  * unless they overflow the (rather big) buffers.
  95                  */
  96                 fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
  97                 vfprintf(stderr, err, params);
  98                 fputc('\n', stderr);
  99                 fflush(stderr);
 100                 break;
 101         case LOG_DESTINATION_NONE:
 102                 break;
 103         case LOG_DESTINATION_UNSET:
 104                 BUG("log destination not initialized correctly");
 105         }
 106 }
 107
 108 __attribute__((format (printf, 1, 2)))
 109 static void logerror(const char *err, ...)
 110 {
 111         va_list params;
 112         va_start(params, err);
 113         logreport(LOG_ERR, err, params);
 114         va_end(params);
 115 }
 116
 117 __attribute__((format (printf, 1, 2)))
 118 static void loginfo(const char *err, ...)
 119 {
 120         va_list params;
 121         if (!verbose)
 122                 return;
 123         va_start(params, err);
 124         logreport(LOG_INFO, err, params);
 125         va_end(params);
 126 }
 127
 128 static void NORETURN daemon_die(const char *err, va_list params)
 129 {
 130         logreport(LOG_ERR, err, params);
 131         exit(1);
 132 }
 133
 134 struct expand_path_context {
 135         const char *directory;
 136         struct hostinfo *hostinfo;
 137 };
 138
 139 static size_t expand_path(struct strbuf *sb, const char *placeholder, void *ctx)
 140 {
 141         struct expand_path_context *context = ctx;
 142         struct hostinfo *hi = context->hostinfo;
 143
 144         switch (placeholder[0]) {
 145         case 'H':
 146                 strbuf_addbuf(sb, &hi->hostname);
 147                 return 1;
 148         case 'C':
 149                 if (placeholder[1] == 'H') {
 150                         strbuf_addstr(sb, get_canon_hostname(hi));
 151                         return 2;
 152                 }
 153                 break;
 154         case 'I':
 155                 if (placeholder[1] == 'P') {
 156                         strbuf_addstr(sb, get_ip_address(hi));
 157                         return 2;
 158                 }
 159                 break;
 160         case 'P':
 161                 strbuf_addbuf(sb, &hi->tcp_port);
 162                 return 1;
 163         case 'D':
 164                 strbuf_addstr(sb, context->directory);
 165                 return 1;
 166         }
 167         return 0;
 168 }
 169
 170 static const char *path_ok(const char *directory, struct hostinfo *hi)
 171 {
 172         static char rpath[PATH_MAX];
 173         static char interp_path[PATH_MAX];
 174         size_t rlen;
 175         const char *path;
 176         const char *dir;
 177
 178         dir = directory;
 179
 180         if (daemon_avoid_alias(dir)) {
 181                 logerror("'%s': aliased", dir);
 182                 return NULL;
 183         }
 184
 185         if (*dir == '~') {
 186                 if (!user_path) {
 187                         logerror("'%s': User-path not allowed", dir);
 188                         return NULL;
 189                 }
 190                 if (*user_path) {
 191                         /* Got either "~alice" or "~alice/foo";
 192                          * rewrite them to "~alice/%s" or
 193                          * "~alice/%s/foo".
 194                          */
 195                         int namlen, restlen = strlen(dir);
 196                         const char *slash = strchr(dir, '/');
 197                         if (!slash)
 198                                 slash = dir + restlen;
 199                         namlen = slash - dir;
 200                         restlen -= namlen;
 201                         loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
 202                         rlen = snprintf(rpath, sizeof(rpath), "%.*s/%s%.*s",
 203                                         namlen, dir, user_path, restlen, slash);
 204                         if (rlen >= sizeof(rpath)) {
 205                                 logerror("user-path too large: %s", rpath);
 206                                 return NULL;
 207                         }
 208                         dir = rpath;
 209                 }
 210         }
 211         else if (interpolated_path && hi->saw_extended_args) {
 212                 struct strbuf expanded_path = STRBUF_INIT;
 213                 struct expand_path_context context;
 214
 215                 context.directory = directory;
 216                 context.hostinfo = hi;
 217
 218                 if (*dir != '/') {
 219                         /* Allow only absolute */
 220                         logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 221                         return NULL;
 222                 }
 223
 224                 strbuf_expand(&expanded_path, interpolated_path,
 225                               expand_path, &context);
 226
 227                 rlen = strlcpy(interp_path, expanded_path.buf,
 228                                sizeof(interp_path));
 229                 if (rlen >= sizeof(interp_path)) {
 230                         logerror("interpolated path too large: %s",
 231                                  interp_path);
 232                         return NULL;
 233                 }
 234
 235                 strbuf_release(&expanded_path);
 236                 loginfo("Interpolated dir '%s'", interp_path);
 237
 238                 dir = interp_path;
 239         }
 240         else if (base_path) {
 241                 if (*dir != '/') {
 242                         /* Allow only absolute */
 243                         logerror("'%s': Non-absolute path denied (base-path active)", dir);
 244                         return NULL;
 245                 }
 246                 rlen = snprintf(rpath, sizeof(rpath), "%s%s", base_path, dir);
 247                 if (rlen >= sizeof(rpath)) {
 248                         logerror("base-path too large: %s", rpath);
 249                         return NULL;
 250                 }
 251                 dir = rpath;
 252         }
 253
 254         path = enter_repo(dir, strict_paths);
 255         if (!path && base_path && base_path_relaxed) {
 256                 /*
 257                  * if we fail and base_path_relaxed is enabled, try without
 258                  * prefixing the base path
 259                  */
 260                 dir = directory;
 261                 path = enter_repo(dir, strict_paths);
 262         }
 263
 264         if (!path) {
 265                 logerror("'%s' does not appear to be a git repository", dir);
 266                 return NULL;
 267         }
 268
 269         if ( ok_paths && *ok_paths ) {
 270                 const char **pp;
 271                 int pathlen = strlen(path);
 272
 273                 /* The validation is done on the paths after enter_repo
 274                  * appends optional {.git,.git/.git} and friends, but
 275                  * it does not use getcwd().  So if your /pub is
 276                  * a symlink to /mnt/pub, you can whitelist /pub and
 277                  * do not have to say /mnt/pub.
 278                  * Do not say /pub/.
 279                  */
 280                 for ( pp = ok_paths ; *pp ; pp++ ) {
 281                         int len = strlen(*pp);
 282                         if (len <= pathlen &&
 283                             !memcmp(*pp, path, len) &&
 284                             (path[len] == '\0' ||
 285                              (!strict_paths && path[len] == '/')))
 286                                 return path;
 287                 }
 288         }
 289         else {
 290                 /* be backwards compatible */
 291                 if (!strict_paths)
 292                         return path;
 293         }
 294
 295         logerror("'%s': not in whitelist", path);
 296         return NULL;            /* Fallthrough. Deny by default */
 297 }
 298
 299 typedef int (*daemon_service_fn)(const struct strvec *env);
 300 struct daemon_service {
 301         const char *name;
 302         const char *config_name;
 303         daemon_service_fn fn;
 304         int enabled;
 305         int overridable;
 306 };
 307
 308 static int daemon_error(const char *dir, const char *msg)
 309 {
 310         if (!informative_errors)
 311                 msg = "access denied or repository not exported";
 312         packet_write_fmt(1, "ERR %s: %s", msg, dir);
 313         return -1;
 314 }
 315
 316 static const char *access_hook;
 317
 318 static int run_access_hook(struct daemon_service *service, const char *dir,
 319                            const char *path, struct hostinfo *hi)
 320 {
 321         struct child_process child = CHILD_PROCESS_INIT;
 322         struct strbuf buf = STRBUF_INIT;
 323         const char *argv[8];
 324         const char **arg = argv;
 325         char *eol;
 326         int seen_errors = 0;
 327
 328         *arg++ = access_hook;
 329         *arg++ = service->name;
 330         *arg++ = path;
 331         *arg++ = hi->hostname.buf;
 332         *arg++ = get_canon_hostname(hi);
 333         *arg++ = get_ip_address(hi);
 334         *arg++ = hi->tcp_port.buf;
 335         *arg = NULL;
 336
 337         child.use_shell = 1;
 338         child.argv = argv;
 339         child.no_stdin = 1;
 340         child.no_stderr = 1;
 341         child.out = -1;
 342         if (start_command(&child)) {
 343                 logerror("daemon access hook '%s' failed to start",
 344                          access_hook);
 345                 goto error_return;
 346         }
 347         if (strbuf_read(&buf, child.out, 0) < 0) {
 348                 logerror("failed to read from pipe to daemon access hook '%s'",
 349                          access_hook);
 350                 strbuf_reset(&buf);
 351                 seen_errors = 1;
 352         }
 353         if (close(child.out) < 0) {
 354                 logerror("failed to close pipe to daemon access hook '%s'",
 355                          access_hook);
 356                 seen_errors = 1;
 357         }
 358         if (finish_command(&child))
 359                 seen_errors = 1;
 360
 361         if (!seen_errors) {
 362                 strbuf_release(&buf);
 363                 return 0;
 364         }
 365
 366 error_return:
 367         strbuf_ltrim(&buf);
 368         if (!buf.len)
 369                 strbuf_addstr(&buf, "service rejected");
 370         eol = strchr(buf.buf, '\n');
 371         if (eol)
 372                 *eol = '\0';
 373         errno = EACCES;
 374         daemon_error(dir, buf.buf);
 375         strbuf_release(&buf);
 376         return -1;
 377 }
 378
 379 static int run_service(const char *dir, struct daemon_service *service,
 380                        struct hostinfo *hi, const struct strvec *env)
 381 {
 382         const char *path;
 383         int enabled = service->enabled;
 384         struct strbuf var = STRBUF_INIT;
 385
 386         loginfo("Request %s for '%s'", service->name, dir);
 387
 388         if (!enabled && !service->overridable) {
 389                 logerror("'%s': service not enabled.", service->name);
 390                 errno = EACCES;
 391                 return daemon_error(dir, "service not enabled");
 392         }
 393
 394         if (!(path = path_ok(dir, hi)))
 395                 return daemon_error(dir, "no such repository");
 396
 397         /*
 398          * Security on the cheap.
 399          *
 400          * We want a readable HEAD, usable "objects" directory, and
 401          * a "git-daemon-export-ok" flag that says that the other side
 402          * is ok with us doing this.
 403          *
 404          * path_ok() uses enter_repo() and does whitelist checking.
 405          * We only need to make sure the repository is exported.
 406          */
 407
 408         if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 409                 logerror("'%s': repository not exported.", path);
 410                 errno = EACCES;
 411                 return daemon_error(dir, "repository not exported");
 412         }
 413
 414         if (service->overridable) {
 415                 strbuf_addf(&var, "daemon.%s", service->config_name);
 416                 git_config_get_bool(var.buf, &enabled);
 417                 strbuf_release(&var);
 418         }
 419         if (!enabled) {
 420                 logerror("'%s': service not enabled for '%s'",
 421                          service->name, path);
 422                 errno = EACCES;
 423                 return daemon_error(dir, "service not enabled");
 424         }
 425
 426         /*
 427          * Optionally, a hook can choose to deny access to the
 428          * repository depending on the phase of the moon.
 429          */
 430         if (access_hook && run_access_hook(service, dir, path, hi))
 431                 return -1;
 432
 433         /*
 434          * We'll ignore SIGTERM from now on, we have a
 435          * good client.
 436          */
 437         signal(SIGTERM, SIG_IGN);
 438
 439         return service->fn(env);
 440 }
 441
 442 static void copy_to_log(int fd)
 443 {
 444         struct strbuf line = STRBUF_INIT;
 445         FILE *fp;
 446
 447         fp = fdopen(fd, "r");
 448         if (fp == NULL) {
 449                 logerror("fdopen of error channel failed");
 450                 close(fd);
 451                 return;
 452         }
 453
 454         while (strbuf_getline_lf(&line, fp) != EOF) {
 455                 logerror("%s", line.buf);
 456                 strbuf_setlen(&line, 0);
 457         }
 458
 459         strbuf_release(&line);
 460         fclose(fp);
 461 }
 462
 463 static int run_service_command(struct child_process *cld)
 464 {
 465         strvec_push(&cld->args, ".");
 466         cld->git_cmd = 1;
 467         cld->err = -1;
 468         if (start_command(cld))
 469                 return -1;
 470
 471         close(0);
 472         close(1);
 473
 474         copy_to_log(cld->err);
 475
 476         return finish_command(cld);
 477 }
 478
 479 static int upload_pack(const struct strvec *env)
 480 {
 481         struct child_process cld = CHILD_PROCESS_INIT;
 482         strvec_pushl(&cld.args, "upload-pack", "--strict", NULL);
 483         strvec_pushf(&cld.args, "--timeout=%u", timeout);
 484
 485         strvec_pushv(&cld.env_array, env->v);
 486
 487         return run_service_command(&cld);
 488 }
 489
 490 static int upload_archive(const struct strvec *env)
 491 {
 492         struct child_process cld = CHILD_PROCESS_INIT;
 493         strvec_push(&cld.args, "upload-archive");
 494
 495         strvec_pushv(&cld.env_array, env->v);
 496
 497         return run_service_command(&cld);
 498 }
 499
 500 static int receive_pack(const struct strvec *env)
 501 {
 502         struct child_process cld = CHILD_PROCESS_INIT;
 503         strvec_push(&cld.args, "receive-pack");
 504
 505         strvec_pushv(&cld.env_array, env->v);
 506
 507         return run_service_command(&cld);
 508 }
 509
 510 static struct daemon_service daemon_service[] = {
 511         { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 512         { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 513         { "receive-pack", "receivepack", receive_pack, 0, 1 },
 514 };
 515
 516 static void enable_service(const char *name, int ena)
 517 {
 518         int i;
 519         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 520                 if (!strcmp(daemon_service[i].name, name)) {
 521                         daemon_service[i].enabled = ena;
 522                         return;
 523                 }
 524         }
 525         die("No such service %s", name);
 526 }
 527
 528 static void make_service_overridable(const char *name, int ena)
 529 {
 530         int i;
 531         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 532                 if (!strcmp(daemon_service[i].name, name)) {
 533                         daemon_service[i].overridable = ena;
 534                         return;
 535                 }
 536         }
 537         die("No such service %s", name);
 538 }
 539
 540 static void parse_host_and_port(char *hostport, char **host,
 541         char **port)
 542 {
 543         if (*hostport == '[') {
 544                 char *end;
 545
 546                 end = strchr(hostport, ']');
 547                 if (!end)
 548                         die("Invalid request ('[' without ']')");
 549                 *end = '\0';
 550                 *host = hostport + 1;
 551                 if (!end[1])
 552                         *port = NULL;
 553                 else if (end[1] == ':')
 554                         *port = end + 2;
 555                 else
 556                         die("Garbage after end of host part");
 557         } else {
 558                 *host = hostport;
 559                 *port = strrchr(hostport, ':');
 560                 if (*port) {
 561                         **port = '\0';
 562                         ++*port;
 563                 }
 564         }
 565 }
 566
 567 /*
 568  * Sanitize a string from the client so that it's OK to be inserted into a
 569  * filesystem path. Specifically, we disallow slashes, runs of "..", and
 570  * trailing and leading dots, which means that the client cannot escape
 571  * our base path via ".." traversal.
 572  */
 573 static void sanitize_client(struct strbuf *out, const char *in)
 574 {
 575         for (; *in; in++) {
 576                 if (*in == '/')
 577                         continue;
 578                 if (*in == '.' && (!out->len || out->buf[out->len - 1] == '.'))
 579                         continue;
 580                 strbuf_addch(out, *in);
 581         }
 582
 583         while (out->len && out->buf[out->len - 1] == '.')
 584                 strbuf_setlen(out, out->len - 1);
 585 }
 586
 587 /*
 588  * Like sanitize_client, but we also perform any canonicalization
 589  * to make life easier on the admin.
 590  */
 591 static void canonicalize_client(struct strbuf *out, const char *in)
 592 {
 593         sanitize_client(out, in);
 594         strbuf_tolower(out);
 595 }
 596
 597 /*
 598  * Read the host as supplied by the client connection.
 599  *
 600  * Returns a pointer to the character after the NUL byte terminating the host
 601  * argument, or 'extra_args' if there is no host argument.
 602  */
 603 static char *parse_host_arg(struct hostinfo *hi, char *extra_args, int buflen)
 604 {
 605         char *val;
 606         int vallen;
 607         char *end = extra_args + buflen;
 608
 609         if (extra_args < end && *extra_args) {
 610                 hi->saw_extended_args = 1;
 611                 if (strncasecmp("host=", extra_args, 5) == 0) {
 612                         val = extra_args + 5;
 613                         vallen = strlen(val) + 1;
 614                         loginfo("Extended attribute \"host\": %s", val);
 615                         if (*val) {
 616                                 /* Split <host>:<port> at colon. */
 617                                 char *host;
 618                                 char *port;
 619                                 parse_host_and_port(val, &host, &port);
 620                                 if (port)
 621                                         sanitize_client(&hi->tcp_port, port);
 622                                 canonicalize_client(&hi->hostname, host);
 623                                 hi->hostname_lookup_done = 0;
 624                         }
 625
 626                         /* On to the next one */
 627                         extra_args = val + vallen;
 628                 }
 629                 if (extra_args < end && *extra_args)
 630                         die("Invalid request");
 631         }
 632
 633         return extra_args;
 634 }
 635
 636 static void parse_extra_args(struct hostinfo *hi, struct strvec *env,
 637                              char *extra_args, int buflen)
 638 {
 639         const char *end = extra_args + buflen;
 640         struct strbuf git_protocol = STRBUF_INIT;
 641
 642         /* First look for the host argument */
 643         extra_args = parse_host_arg(hi, extra_args, buflen);
 644
 645         /* Look for additional arguments places after a second NUL byte */
 646         for (; extra_args < end; extra_args += strlen(extra_args) + 1) {
 647                 const char *arg = extra_args;
 648
 649                 /*
 650                  * Parse the extra arguments, adding most to 'git_protocol'
 651                  * which will be used to set the 'GIT_PROTOCOL' envvar in the
 652                  * service that will be run.
 653                  *
 654                  * If there ends up being a particular arg in the future that
 655                  * git-daemon needs to parse specifically (like the 'host' arg)
 656                  * then it can be parsed here and not added to 'git_protocol'.
 657                  */
 658                 if (*arg) {
 659                         if (git_protocol.len > 0)
 660                                 strbuf_addch(&git_protocol, ':');
 661                         strbuf_addstr(&git_protocol, arg);
 662                 }
 663         }
 664
 665         if (git_protocol.len > 0) {
 666                 loginfo("Extended attribute \"protocol\": %s", git_protocol.buf);
 667                 strvec_pushf(env, GIT_PROTOCOL_ENVIRONMENT "=%s",
 668                              git_protocol.buf);
 669         }
 670         strbuf_release(&git_protocol);
 671 }
 672
 673 /*
 674  * Locate canonical hostname and its IP address.
 675  */
 676 static void lookup_hostname(struct hostinfo *hi)
 677 {
 678         if (!hi->hostname_lookup_done && hi->hostname.len) {
 679 #ifndef NO_IPV6
 680                 struct addrinfo hints;
 681                 struct addrinfo *ai;
 682                 int gai;
 683                 static char addrbuf[HOST_NAME_MAX + 1];
 684
 685                 memset(&hints, 0, sizeof(hints));
 686                 hints.ai_flags = AI_CANONNAME;
 687
 688                 gai = getaddrinfo(hi->hostname.buf, NULL, &hints, &ai);
 689                 if (!gai) {
 690                         struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 691
 692                         inet_ntop(AF_INET, &sin_addr->sin_addr,
 693                                   addrbuf, sizeof(addrbuf));
 694                         strbuf_addstr(&hi->ip_address, addrbuf);
 695
 696                         if (ai->ai_canonname)
 697                                 sanitize_client(&hi->canon_hostname,
 698                                                 ai->ai_canonname);
 699                         else
 700                                 strbuf_addbuf(&hi->canon_hostname,
 701                                               &hi->ip_address);
 702
 703                         freeaddrinfo(ai);
 704                 }
 705 #else
 706                 struct hostent *hent;
 707                 struct sockaddr_in sa;
 708                 char **ap;
 709                 static char addrbuf[HOST_NAME_MAX + 1];
 710
 711                 hent = gethostbyname(hi->hostname.buf);
 712                 if (hent) {
 713                         ap = hent->h_addr_list;
 714                         memset(&sa, 0, sizeof sa);
 715                         sa.sin_family = hent->h_addrtype;
 716                         sa.sin_port = htons(0);
 717                         memcpy(&sa.sin_addr, *ap, hent->h_length);
 718
 719                         inet_ntop(hent->h_addrtype, &sa.sin_addr,
 720                                   addrbuf, sizeof(addrbuf));
 721
 722                         sanitize_client(&hi->canon_hostname, hent->h_name);
 723                         strbuf_addstr(&hi->ip_address, addrbuf);
 724                 }
 725 #endif
 726                 hi->hostname_lookup_done = 1;
 727         }
 728 }
 729
 730 static void hostinfo_init(struct hostinfo *hi)
 731 {
 732         memset(hi, 0, sizeof(*hi));
 733         strbuf_init(&hi->hostname, 0);
 734         strbuf_init(&hi->canon_hostname, 0);
 735         strbuf_init(&hi->ip_address, 0);
 736         strbuf_init(&hi->tcp_port, 0);
 737 }
 738
 739 static void hostinfo_clear(struct hostinfo *hi)
 740 {
 741         strbuf_release(&hi->hostname);
 742         strbuf_release(&hi->canon_hostname);
 743         strbuf_release(&hi->ip_address);
 744         strbuf_release(&hi->tcp_port);
 745 }
 746
 747 static void set_keep_alive(int sockfd)
 748 {
 749         int ka = 1;
 750
 751         if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0) {
 752                 if (errno != ENOTSOCK)
 753                         logerror("unable to set SO_KEEPALIVE on socket: %s",
 754                                 strerror(errno));
 755         }
 756 }
 757
 758 static int execute(void)
 759 {
 760         char *line = packet_buffer;
 761         int pktlen, len, i;
 762         char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
 763         struct hostinfo hi;
 764         struct strvec env = STRVEC_INIT;
 765
 766         hostinfo_init(&hi);
 767
 768         if (addr)
 769                 loginfo("Connection from %s:%s", addr, port);
 770
 771         set_keep_alive(0);
 772         alarm(init_timeout ? init_timeout : timeout);
 773         pktlen = packet_read(0, NULL, NULL, packet_buffer, sizeof(packet_buffer), 0);
 774         alarm(0);
 775
 776         len = strlen(line);
 777         if (len && line[len-1] == '\n')
 778                 line[len-1] = 0;
 779
 780         /* parse additional args hidden behind a NUL byte */
 781         if (len != pktlen)
 782                 parse_extra_args(&hi, &env, line + len + 1, pktlen - len - 1);
 783
 784         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 785                 struct daemon_service *s = &(daemon_service[i]);
 786                 const char *arg;
 787
 788                 if (skip_prefix(line, "git-", &arg) &&
 789                     skip_prefix(arg, s->name, &arg) &&
 790                     *arg++ == ' ') {
 791                         /*
 792                          * Note: The directory here is probably context sensitive,
 793                          * and might depend on the actual service being performed.
 794                          */
 795                         int rc = run_service(arg, s, &hi, &env);
 796                         hostinfo_clear(&hi);
 797                         strvec_clear(&env);
 798                         return rc;
 799                 }
 800         }
 801
 802         hostinfo_clear(&hi);
 803         strvec_clear(&env);
 804         logerror("Protocol error: '%s'", line);
 805         return -1;
 806 }
 807
 808 static int addrcmp(const struct sockaddr_storage *s1,
 809     const struct sockaddr_storage *s2)
 810 {
 811         const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 812         const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 813
 814         if (sa1->sa_family != sa2->sa_family)
 815                 return sa1->sa_family - sa2->sa_family;
 816         if (sa1->sa_family == AF_INET)
 817                 return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 818                     &((struct sockaddr_in *)s2)->sin_addr,
 819                     sizeof(struct in_addr));
 820 #ifndef NO_IPV6
 821         if (sa1->sa_family == AF_INET6)
 822                 return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 823                     &((struct sockaddr_in6 *)s2)->sin6_addr,
 824                     sizeof(struct in6_addr));
 825 #endif
 826         return 0;
 827 }
 828
 829 static int max_connections = 32;
 830
 831 static unsigned int live_children;
 832
 833 static struct child {
 834         struct child *next;
 835         struct child_process cld;
 836         struct sockaddr_storage address;
 837 } *firstborn;
 838
 839 static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
 840 {
 841         struct child *newborn, **cradle;
 842
 843         newborn = xcalloc(1, sizeof(*newborn));
 844         live_children++;
 845         memcpy(&newborn->cld, cld, sizeof(*cld));
 846         memcpy(&newborn->address, addr, addrlen);
 847         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 848                 if (!addrcmp(&(*cradle)->address, &newborn->address))
 849                         break;
 850         newborn->next = *cradle;
 851         *cradle = newborn;
 852 }
 853
 854 /*
 855  * This gets called if the number of connections grows
 856  * past "max_connections".
 857  *
 858  * We kill the newest connection from a duplicate IP.
 859  */
 860 static void kill_some_child(void)
 861 {
 862         const struct child *blanket, *next;
 863
 864         if (!(blanket = firstborn))
 865                 return;
 866
 867         for (; (next = blanket->next); blanket = next)
 868                 if (!addrcmp(&blanket->address, &next->address)) {
 869                         kill(blanket->cld.pid, SIGTERM);
 870                         break;
 871                 }
 872 }
 873
 874 static void check_dead_children(void)
 875 {
 876         int status;
 877         pid_t pid;
 878
 879         struct child **cradle, *blanket;
 880         for (cradle = &firstborn; (blanket = *cradle);)
 881                 if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
 882                         const char *dead = "";
 883                         if (status)
 884                                 dead = " (with error)";
 885                         loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 886
 887                         /* remove the child */
 888                         *cradle = blanket->next;
 889                         live_children--;
 890                         child_process_clear(&blanket->cld);
 891                         free(blanket);
 892                 } else
 893                         cradle = &blanket->next;
 894 }
 895
 896 static struct strvec cld_argv = STRVEC_INIT;
 897 static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 898 {
 899         struct child_process cld = CHILD_PROCESS_INIT;
 900
 901         if (max_connections && live_children >= max_connections) {
 902                 kill_some_child();
 903                 sleep(1);  /* give it some time to die */
 904                 check_dead_children();
 905                 if (live_children >= max_connections) {
 906                         close(incoming);
 907                         logerror("Too many children, dropping connection");
 908                         return;
 909                 }
 910         }
 911
 912         if (addr->sa_family == AF_INET) {
 913                 char buf[128] = "";
 914                 struct sockaddr_in *sin_addr = (void *) addr;
 915                 inet_ntop(addr->sa_family, &sin_addr->sin_addr, buf, sizeof(buf));
 916                 strvec_pushf(&cld.env_array, "REMOTE_ADDR=%s", buf);
 917                 strvec_pushf(&cld.env_array, "REMOTE_PORT=%d",
 918                              ntohs(sin_addr->sin_port));
 919 #ifndef NO_IPV6
 920         } else if (addr->sa_family == AF_INET6) {
 921                 char buf[128] = "";
 922                 struct sockaddr_in6 *sin6_addr = (void *) addr;
 923                 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(buf));
 924                 strvec_pushf(&cld.env_array, "REMOTE_ADDR=[%s]", buf);
 925                 strvec_pushf(&cld.env_array, "REMOTE_PORT=%d",
 926                              ntohs(sin6_addr->sin6_port));
 927 #endif
 928         }
 929
 930         cld.argv = cld_argv.v;
 931         cld.in = incoming;
 932         cld.out = dup(incoming);
 933
 934         if (start_command(&cld))
 935                 logerror("unable to fork");
 936         else
 937                 add_child(&cld, addr, addrlen);
 938 }
 939
 940 static void child_handler(int signo)
 941 {
 942         /*
 943          * Otherwise empty handler because systemcalls will get interrupted
 944          * upon signal receipt
 945          * SysV needs the handler to be rearmed
 946          */
 947         signal(SIGCHLD, child_handler);
 948 }
 949
 950 static int set_reuse_addr(int sockfd)
 951 {
 952         int on = 1;
 953
 954         if (!reuseaddr)
 955                 return 0;
 956         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 957                           &on, sizeof(on));
 958 }
 959
 960 struct socketlist {
 961         int *list;
 962         size_t nr;
 963         size_t alloc;
 964 };
 965
 966 static const char *ip2str(int family, struct sockaddr *sin, socklen_t len)
 967 {
 968 #ifdef NO_IPV6
 969         static char ip[INET_ADDRSTRLEN];
 970 #else
 971         static char ip[INET6_ADDRSTRLEN];
 972 #endif
 973
 974         switch (family) {
 975 #ifndef NO_IPV6
 976         case AF_INET6:
 977                 inet_ntop(family, &((struct sockaddr_in6*)sin)->sin6_addr, ip, len);
 978                 break;
 979 #endif
 980         case AF_INET:
 981                 inet_ntop(family, &((struct sockaddr_in*)sin)->sin_addr, ip, len);
 982                 break;
 983         default:
 984                 xsnprintf(ip, sizeof(ip), "<unknown>");
 985         }
 986         return ip;
 987 }
 988
 989 #ifndef NO_IPV6
 990
 991 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 992 {
 993         int socknum = 0;
 994         char pbuf[NI_MAXSERV];
 995         struct addrinfo hints, *ai0, *ai;
 996         int gai;
 997         long flags;
 998
 999         xsnprintf(pbuf, sizeof(pbuf), "%d", listen_port);
1000         memset(&hints, 0, sizeof(hints));
1001         hints.ai_family = AF_UNSPEC;
1002         hints.ai_socktype = SOCK_STREAM;
1003         hints.ai_protocol = IPPROTO_TCP;
1004         hints.ai_flags = AI_PASSIVE;
1005
1006         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
1007         if (gai) {
1008                 logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
1009                 return 0;
1010         }
1011
1012         for (ai = ai0; ai; ai = ai->ai_next) {
1013                 int sockfd;
1014
1015                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
1016                 if (sockfd < 0)
1017                         continue;
1018                 if (sockfd >= FD_SETSIZE) {
1019                         logerror("Socket descriptor too large");
1020                         close(sockfd);
1021                         continue;
1022                 }
1023
1024 #ifdef IPV6_V6ONLY
1025                 if (ai->ai_family == AF_INET6) {
1026                         int on = 1;
1027                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
1028                                    &on, sizeof(on));
1029                         /* Note: error is not fatal */
1030                 }
1031 #endif
1032
1033                 if (set_reuse_addr(sockfd)) {
1034                         logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
1035                         close(sockfd);
1036                         continue;
1037                 }
1038
1039                 set_keep_alive(sockfd);
1040
1041                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
1042                         logerror("Could not bind to %s: %s",
1043                                  ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
1044                                  strerror(errno));
1045                         close(sockfd);
1046                         continue;       /* not fatal */
1047                 }
1048                 if (listen(sockfd, 5) < 0) {
1049                         logerror("Could not listen to %s: %s",
1050                                  ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
1051                                  strerror(errno));
1052                         close(sockfd);
1053                         continue;       /* not fatal */
1054                 }
1055
1056                 flags = fcntl(sockfd, F_GETFD, 0);
1057                 if (flags >= 0)
1058                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
1059
1060                 ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
1061                 socklist->list[socklist->nr++] = sockfd;
1062                 socknum++;
1063         }
1064
1065         freeaddrinfo(ai0);
1066
1067         return socknum;
1068 }
1069
1070 #else /* NO_IPV6 */
1071
1072 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
1073 {
1074         struct sockaddr_in sin;
1075         int sockfd;
1076         long flags;
1077
1078         memset(&sin, 0, sizeof sin);
1079         sin.sin_family = AF_INET;
1080         sin.sin_port = htons(listen_port);
1081
1082         if (listen_addr) {
1083                 /* Well, host better be an IP address here. */
1084                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
1085                         return 0;
1086         } else {
1087                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
1088         }
1089
1090         sockfd = socket(AF_INET, SOCK_STREAM, 0);
1091         if (sockfd < 0)
1092                 return 0;
1093
1094         if (set_reuse_addr(sockfd)) {
1095                 logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
1096                 close(sockfd);
1097                 return 0;
1098         }
1099
1100         set_keep_alive(sockfd);
1101
1102         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
1103                 logerror("Could not bind to %s: %s",
1104                          ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
1105                          strerror(errno));
1106                 close(sockfd);
1107                 return 0;
1108         }
1109
1110         if (listen(sockfd, 5) < 0) {
1111                 logerror("Could not listen to %s: %s",
1112                          ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
1113                          strerror(errno));
1114                 close(sockfd);
1115                 return 0;
1116         }
1117
1118         flags = fcntl(sockfd, F_GETFD, 0);
1119         if (flags >= 0)
1120                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
1121
1122         ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
1123         socklist->list[socklist->nr++] = sockfd;
1124         return 1;
1125 }
1126
1127 #endif
1128
1129 static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
1130 {
1131         if (!listen_addr->nr)
1132                 setup_named_sock(NULL, listen_port, socklist);
1133         else {
1134                 int i, socknum;
1135                 for (i = 0; i < listen_addr->nr; i++) {
1136                         socknum = setup_named_sock(listen_addr->items[i].string,
1137                                                    listen_port, socklist);
1138
1139                         if (socknum == 0)
1140                                 logerror("unable to allocate any listen sockets for host %s on port %u",
1141                                          listen_addr->items[i].string, listen_port);
1142                 }
1143         }
1144 }
1145
1146 static int service_loop(struct socketlist *socklist)
1147 {
1148         struct pollfd *pfd;
1149         int i;
1150
1151         pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
1152
1153         for (i = 0; i < socklist->nr; i++) {
1154                 pfd[i].fd = socklist->list[i];
1155                 pfd[i].events = POLLIN;
1156         }
1157
1158         signal(SIGCHLD, child_handler);
1159
1160         for (;;) {
1161                 int i;
1162
1163                 check_dead_children();
1164
1165                 if (poll(pfd, socklist->nr, -1) < 0) {
1166                         if (errno != EINTR) {
1167                                 logerror("Poll failed, resuming: %s",
1168                                       strerror(errno));
1169                                 sleep(1);
1170                         }
1171                         continue;
1172                 }
1173
1174                 for (i = 0; i < socklist->nr; i++) {
1175                         if (pfd[i].revents & POLLIN) {
1176                                 union {
1177                                         struct sockaddr sa;
1178                                         struct sockaddr_in sai;
1179 #ifndef NO_IPV6
1180                                         struct sockaddr_in6 sai6;
1181 #endif
1182                                 } ss;
1183                                 socklen_t sslen = sizeof(ss);
1184                                 int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
1185                                 if (incoming < 0) {
1186                                         switch (errno) {
1187                                         case EAGAIN:
1188                                         case EINTR:
1189                                         case ECONNABORTED:
1190                                                 continue;
1191                                         default:
1192                                                 die_errno("accept returned");
1193                                         }
1194                                 }
1195                                 handle(incoming, &ss.sa, sslen);
1196                         }
1197                 }
1198         }
1199 }
1200
1201 #ifdef NO_POSIX_GOODIES
1202
1203 struct credentials;
1204
1205 static void drop_privileges(struct credentials *cred)
1206 {
1207         /* nothing */
1208 }
1209
1210 static struct credentials *prepare_credentials(const char *user_name,
1211     const char *group_name)
1212 {
1213         die("--user not supported on this platform");
1214 }
1215
1216 #else
1217
1218 struct credentials {
1219         struct passwd *pass;
1220         gid_t gid;
1221 };
1222
1223 static void drop_privileges(struct credentials *cred)
1224 {
1225         if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
1226             setgid (cred->gid) || setuid(cred->pass->pw_uid)))
1227                 die("cannot drop privileges");
1228 }
1229
1230 static struct credentials *prepare_credentials(const char *user_name,
1231     const char *group_name)
1232 {
1233         static struct credentials c;
1234
1235         c.pass = getpwnam(user_name);
1236         if (!c.pass)
1237                 die("user not found - %s", user_name);
1238
1239         if (!group_name)
1240                 c.gid = c.pass->pw_gid;
1241         else {
1242                 struct group *group = getgrnam(group_name);
1243                 if (!group)
1244                         die("group not found - %s", group_name);
1245
1246                 c.gid = group->gr_gid;
1247         }
1248
1249         return &c;
1250 }
1251 #endif
1252
1253 static int serve(struct string_list *listen_addr, int listen_port,
1254     struct credentials *cred)
1255 {
1256         struct socketlist socklist = { NULL, 0, 0 };
1257
1258         socksetup(listen_addr, listen_port, &socklist);
1259         if (socklist.nr == 0)
1260                 die("unable to allocate any listen sockets on port %u",
1261                     listen_port);
1262
1263         drop_privileges(cred);
1264
1265         loginfo("Ready to rumble");
1266
1267         return service_loop(&socklist);
1268 }
1269
1270 int cmd_main(int argc, const char **argv)
1271 {
1272         int listen_port = 0;
1273         struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1274         int serve_mode = 0, inetd_mode = 0;
1275         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1276         int detach = 0;
1277         struct credentials *cred = NULL;
1278         int i;
1279
1280         for (i = 1; i < argc; i++) {
1281                 const char *arg = argv[i];
1282                 const char *v;
1283
1284                 if (skip_prefix(arg, "--listen=", &v)) {
1285                         string_list_append(&listen_addr, xstrdup_tolower(v));
1286                         continue;
1287                 }
1288                 if (skip_prefix(arg, "--port=", &v)) {
1289                         char *end;
1290                         unsigned long n;
1291                         n = strtoul(v, &end, 0);
1292                         if (*v && !*end) {
1293                                 listen_port = n;
1294                                 continue;
1295                         }
1296                 }
1297                 if (!strcmp(arg, "--serve")) {
1298                         serve_mode = 1;
1299                         continue;
1300                 }
1301                 if (!strcmp(arg, "--inetd")) {
1302                         inetd_mode = 1;
1303                         continue;
1304                 }
1305                 if (!strcmp(arg, "--verbose")) {
1306                         verbose = 1;
1307                         continue;
1308                 }
1309                 if (!strcmp(arg, "--syslog")) {
1310                         log_destination = LOG_DESTINATION_SYSLOG;
1311                         continue;
1312                 }
1313                 if (skip_prefix(arg, "--log-destination=", &v)) {
1314                         if (!strcmp(v, "syslog")) {
1315                                 log_destination = LOG_DESTINATION_SYSLOG;
1316                                 continue;
1317                         } else if (!strcmp(v, "stderr")) {
1318                                 log_destination = LOG_DESTINATION_STDERR;
1319                                 continue;
1320                         } else if (!strcmp(v, "none")) {
1321                                 log_destination = LOG_DESTINATION_NONE;
1322                                 continue;
1323                         } else
1324                                 die("unknown log destination '%s'", v);
1325                 }
1326                 if (!strcmp(arg, "--export-all")) {
1327                         export_all_trees = 1;
1328                         continue;
1329                 }
1330                 if (skip_prefix(arg, "--access-hook=", &v)) {
1331                         access_hook = v;
1332                         continue;
1333                 }
1334                 if (skip_prefix(arg, "--timeout=", &v)) {
1335                         timeout = atoi(v);
1336                         continue;
1337                 }
1338                 if (skip_prefix(arg, "--init-timeout=", &v)) {
1339                         init_timeout = atoi(v);
1340                         continue;
1341                 }
1342                 if (skip_prefix(arg, "--max-connections=", &v)) {
1343                         max_connections = atoi(v);
1344                         if (max_connections < 0)
1345                                 max_connections = 0;            /* unlimited */
1346                         continue;
1347                 }
1348                 if (!strcmp(arg, "--strict-paths")) {
1349                         strict_paths = 1;
1350                         continue;
1351                 }
1352                 if (skip_prefix(arg, "--base-path=", &v)) {
1353                         base_path = v;
1354                         continue;
1355                 }
1356                 if (!strcmp(arg, "--base-path-relaxed")) {
1357                         base_path_relaxed = 1;
1358                         continue;
1359                 }
1360                 if (skip_prefix(arg, "--interpolated-path=", &v)) {
1361                         interpolated_path = v;
1362                         continue;
1363                 }
1364                 if (!strcmp(arg, "--reuseaddr")) {
1365                         reuseaddr = 1;
1366                         continue;
1367                 }
1368                 if (!strcmp(arg, "--user-path")) {
1369                         user_path = "";
1370                         continue;
1371                 }
1372                 if (skip_prefix(arg, "--user-path=", &v)) {
1373                         user_path = v;
1374                         continue;
1375                 }
1376                 if (skip_prefix(arg, "--pid-file=", &v)) {
1377                         pid_file = v;
1378                         continue;
1379                 }
1380                 if (!strcmp(arg, "--detach")) {
1381                         detach = 1;
1382                         continue;
1383                 }
1384                 if (skip_prefix(arg, "--user=", &v)) {
1385                         user_name = v;
1386                         continue;
1387                 }
1388                 if (skip_prefix(arg, "--group=", &v)) {
1389                         group_name = v;
1390                         continue;
1391                 }
1392                 if (skip_prefix(arg, "--enable=", &v)) {
1393                         enable_service(v, 1);
1394                         continue;
1395                 }
1396                 if (skip_prefix(arg, "--disable=", &v)) {
1397                         enable_service(v, 0);
1398                         continue;
1399                 }
1400                 if (skip_prefix(arg, "--allow-override=", &v)) {
1401                         make_service_overridable(v, 1);
1402                         continue;
1403                 }
1404                 if (skip_prefix(arg, "--forbid-override=", &v)) {
1405                         make_service_overridable(v, 0);
1406                         continue;
1407                 }
1408                 if (!strcmp(arg, "--informative-errors")) {
1409                         informative_errors = 1;
1410                         continue;
1411                 }
1412                 if (!strcmp(arg, "--no-informative-errors")) {
1413                         informative_errors = 0;
1414                         continue;
1415                 }
1416                 if (!strcmp(arg, "--")) {
1417                         ok_paths = &argv[i+1];
1418                         break;
1419                 } else if (arg[0] != '-') {
1420                         ok_paths = &argv[i];
1421                         break;
1422                 }
1423
1424                 usage(daemon_usage);
1425         }
1426
1427         if (log_destination == LOG_DESTINATION_UNSET) {
1428                 if (inetd_mode || detach)
1429                         log_destination = LOG_DESTINATION_SYSLOG;
1430                 else
1431                         log_destination = LOG_DESTINATION_STDERR;
1432         }
1433
1434         if (log_destination == LOG_DESTINATION_SYSLOG) {
1435                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1436                 set_die_routine(daemon_die);
1437         } else
1438                 /* avoid splitting a message in the middle */
1439                 setvbuf(stderr, NULL, _IOFBF, 4096);
1440
1441         if (inetd_mode && (detach || group_name || user_name))
1442                 die("--detach, --user and --group are incompatible with --inetd");
1443
1444         if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1445                 die("--listen= and --port= are incompatible with --inetd");
1446         else if (listen_port == 0)
1447                 listen_port = DEFAULT_GIT_PORT;
1448
1449         if (group_name && !user_name)
1450                 die("--group supplied without --user");
1451
1452         if (user_name)
1453                 cred = prepare_credentials(user_name, group_name);
1454
1455         if (strict_paths && (!ok_paths || !*ok_paths))
1456                 die("option --strict-paths requires a whitelist");
1457
1458         if (base_path && !is_directory(base_path))
1459                 die("base-path '%s' does not exist or is not a directory",
1460                     base_path);
1461
1462         if (log_destination != LOG_DESTINATION_STDERR) {
1463                 if (!freopen("/dev/null", "w", stderr))
1464                         die_errno("failed to redirect stderr to /dev/null");
1465         }
1466
1467         if (inetd_mode || serve_mode)
1468                 return execute();
1469
1470         if (detach) {
1471                 if (daemonize())
1472                         die("--detach not supported on this platform");
1473         }
1474
1475         if (pid_file)
1476                 write_file(pid_file, "%"PRIuMAX, (uintmax_t) getpid());
1477
1478         /* prepare argv for serving-processes */
1479         strvec_push(&cld_argv, argv[0]); /* git-daemon */
1480         strvec_push(&cld_argv, "--serve");
1481         for (i = 1; i < argc; ++i)
1482                 strvec_push(&cld_argv, argv[i]);
1483
1484         return serve(&listen_addr, listen_port, cred);
1485 }