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