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         const char *argv[8];
 330         const char **arg = argv;
 331         char *eol;
 332         int seen_errors = 0;
 333
 334         *arg++ = access_hook;
 335         *arg++ = service->name;
 336         *arg++ = path;
 337         *arg++ = hi->hostname.buf;
 338         *arg++ = get_canon_hostname(hi);
 339         *arg++ = get_ip_address(hi);
 340         *arg++ = hi->tcp_port.buf;
 341         *arg = NULL;
 342
 343         child.use_shell = 1;
 344         child.argv = argv;
 345         child.no_stdin = 1;
 346         child.no_stderr = 1;
 347         child.out = -1;
 348         if (start_command(&child)) {
 349                 logerror("daemon access hook '%s' failed to start",
 350                          access_hook);
 351                 goto error_return;
 352         }
 353         if (strbuf_read(&buf, child.out, 0) < 0) {
 354                 logerror("failed to read from pipe to daemon access hook '%s'",
 355                          access_hook);
 356                 strbuf_reset(&buf);
 357                 seen_errors = 1;
 358         }
 359         if (close(child.out) < 0) {
 360                 logerror("failed to close pipe to daemon access hook '%s'",
 361                          access_hook);
 362                 seen_errors = 1;
 363         }
 364         if (finish_command(&child))
 365                 seen_errors = 1;
 366
 367         if (!seen_errors) {
 368                 strbuf_release(&buf);
 369                 return 0;
 370         }
 371
 372 error_return:
 373         strbuf_ltrim(&buf);
 374         if (!buf.len)
 375                 strbuf_addstr(&buf, "service rejected");
 376         eol = strchr(buf.buf, '\n');
 377         if (eol)
 378                 *eol = '\0';
 379         errno = EACCES;
 380         daemon_error(dir, buf.buf);
 381         strbuf_release(&buf);
 382         return -1;
 383 }
 384
 385 static int run_service(const char *dir, struct daemon_service *service,
 386                        struct hostinfo *hi, const struct strvec *env)
 387 {
 388         const char *path;
 389         int enabled = service->enabled;
 390         struct strbuf var = STRBUF_INIT;
 391
 392         loginfo("Request %s for '%s'", service->name, dir);
 393
 394         if (!enabled && !service->overridable) {
 395                 logerror("'%s': service not enabled.", service->name);
 396                 errno = EACCES;
 397                 return daemon_error(dir, "service not enabled");
 398         }
 399
 400         if (!(path = path_ok(dir, hi)))
 401                 return daemon_error(dir, "no such repository");
 402
 403         /*
 404          * Security on the cheap.
 405          *
 406          * We want a readable HEAD, usable "objects" directory, and
 407          * a "git-daemon-export-ok" flag that says that the other side
 408          * is ok with us doing this.
 409          *
 410          * path_ok() uses enter_repo() and does whitelist checking.
 411          * We only need to make sure the repository is exported.
 412          */
 413
 414         if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 415                 logerror("'%s': repository not exported.", path);
 416                 errno = EACCES;
 417                 return daemon_error(dir, "repository not exported");
 418         }
 419
 420         if (service->overridable) {
 421                 strbuf_addf(&var, "daemon.%s", service->config_name);
 422                 git_config_get_bool(var.buf, &enabled);
 423                 strbuf_release(&var);
 424         }
 425         if (!enabled) {
 426                 logerror("'%s': service not enabled for '%s'",
 427                          service->name, path);
 428                 errno = EACCES;
 429                 return daemon_error(dir, "service not enabled");
 430         }
 431
 432         /*
 433          * Optionally, a hook can choose to deny access to the
 434          * repository depending on the phase of the moon.
 435          */
 436         if (access_hook && run_access_hook(service, dir, path, hi))
 437                 return -1;
 438
 439         /*
 440          * We'll ignore SIGTERM from now on, we have a
 441          * good client.
 442          */
 443         signal(SIGTERM, SIG_IGN);
 444
 445         return service->fn(env);
 446 }
 447
 448 static void copy_to_log(int fd)
 449 {
 450         struct strbuf line = STRBUF_INIT;
 451         FILE *fp;
 452
 453         fp = fdopen(fd, "r");
 454         if (fp == NULL) {
 455                 logerror("fdopen of error channel failed");
 456                 close(fd);
 457                 return;
 458         }
 459
 460         while (strbuf_getline_lf(&line, fp) != EOF) {
 461                 logerror("%s", line.buf);
 462                 strbuf_setlen(&line, 0);
 463         }
 464
 465         strbuf_release(&line);
 466         fclose(fp);
 467 }
 468
 469 static int run_service_command(struct child_process *cld)
 470 {
 471         strvec_push(&cld->args, ".");
 472         cld->git_cmd = 1;
 473         cld->err = -1;
 474         if (start_command(cld))
 475                 return -1;
 476
 477         close(0);
 478         close(1);
 479
 480         copy_to_log(cld->err);
 481
 482         return finish_command(cld);
 483 }
 484
 485 static int upload_pack(const struct strvec *env)
 486 {
 487         struct child_process cld = CHILD_PROCESS_INIT;
 488         strvec_pushl(&cld.args, "upload-pack", "--strict", NULL);
 489         strvec_pushf(&cld.args, "--timeout=%u", timeout);
 490
 491         strvec_pushv(&cld.env_array, env->v);
 492
 493         return run_service_command(&cld);
 494 }
 495
 496 static int upload_archive(const struct strvec *env)
 497 {
 498         struct child_process cld = CHILD_PROCESS_INIT;
 499         strvec_push(&cld.args, "upload-archive");
 500
 501         strvec_pushv(&cld.env_array, env->v);
 502
 503         return run_service_command(&cld);
 504 }
 505
 506 static int receive_pack(const struct strvec *env)
 507 {
 508         struct child_process cld = CHILD_PROCESS_INIT;
 509         strvec_push(&cld.args, "receive-pack");
 510
 511         strvec_pushv(&cld.env_array, env->v);
 512
 513         return run_service_command(&cld);
 514 }
 515
 516 static struct daemon_service daemon_service[] = {
 517         { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 518         { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 519         { "receive-pack", "receivepack", receive_pack, 0, 1 },
 520 };
 521
 522 static void enable_service(const char *name, int ena)
 523 {
 524         int i;
 525         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 526                 if (!strcmp(daemon_service[i].name, name)) {
 527                         daemon_service[i].enabled = ena;
 528                         return;
 529                 }
 530         }
 531         die("No such service %s", name);
 532 }
 533
 534 static void make_service_overridable(const char *name, int ena)
 535 {
 536         int i;
 537         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 538                 if (!strcmp(daemon_service[i].name, name)) {
 539                         daemon_service[i].overridable = ena;
 540                         return;
 541                 }
 542         }
 543         die("No such service %s", name);
 544 }
 545
 546 static void parse_host_and_port(char *hostport, char **host,
 547         char **port)
 548 {
 549         if (*hostport == '[') {
 550                 char *end;
 551
 552                 end = strchr(hostport, ']');
 553                 if (!end)
 554                         die("Invalid request ('[' without ']')");
 555                 *end = '\0';
 556                 *host = hostport + 1;
 557                 if (!end[1])
 558                         *port = NULL;
 559                 else if (end[1] == ':')
 560                         *port = end + 2;
 561                 else
 562                         die("Garbage after end of host part");
 563         } else {
 564                 *host = hostport;
 565                 *port = strrchr(hostport, ':');
 566                 if (*port) {
 567                         **port = '\0';
 568                         ++*port;
 569                 }
 570         }
 571 }
 572
 573 /*
 574  * Sanitize a string from the client so that it's OK to be inserted into a
 575  * filesystem path. Specifically, we disallow directory separators, runs
 576  * of "..", and trailing and leading dots, which means that the client
 577  * cannot escape our base path via ".." traversal.
 578  */
 579 static void sanitize_client(struct strbuf *out, const char *in)
 580 {
 581         for (; *in; in++) {
 582                 if (is_dir_sep(*in))
 583                         continue;
 584                 if (*in == '.' && (!out->len || out->buf[out->len - 1] == '.'))
 585                         continue;
 586                 strbuf_addch(out, *in);
 587         }
 588
 589         while (out->len && out->buf[out->len - 1] == '.')
 590                 strbuf_setlen(out, out->len - 1);
 591 }
 592
 593 /*
 594  * Like sanitize_client, but we also perform any canonicalization
 595  * to make life easier on the admin.
 596  */
 597 static void canonicalize_client(struct strbuf *out, const char *in)
 598 {
 599         sanitize_client(out, in);
 600         strbuf_tolower(out);
 601 }
 602
 603 /*
 604  * Read the host as supplied by the client connection.
 605  *
 606  * Returns a pointer to the character after the NUL byte terminating the host
 607  * argument, or 'extra_args' if there is no host argument.
 608  */
 609 static char *parse_host_arg(struct hostinfo *hi, char *extra_args, int buflen)
 610 {
 611         char *val;
 612         int vallen;
 613         char *end = extra_args + buflen;
 614
 615         if (extra_args < end && *extra_args) {
 616                 hi->saw_extended_args = 1;
 617                 if (strncasecmp("host=", extra_args, 5) == 0) {
 618                         val = extra_args + 5;
 619                         vallen = strlen(val) + 1;
 620                         loginfo("Extended attribute \"host\": %s", val);
 621                         if (*val) {
 622                                 /* Split <host>:<port> at colon. */
 623                                 char *host;
 624                                 char *port;
 625                                 parse_host_and_port(val, &host, &port);
 626                                 if (port)
 627                                         sanitize_client(&hi->tcp_port, port);
 628                                 canonicalize_client(&hi->hostname, host);
 629                                 hi->hostname_lookup_done = 0;
 630                         }
 631
 632                         /* On to the next one */
 633                         extra_args = val + vallen;
 634                 }
 635                 if (extra_args < end && *extra_args)
 636                         die("Invalid request");
 637         }
 638
 639         return extra_args;
 640 }
 641
 642 static void parse_extra_args(struct hostinfo *hi, struct strvec *env,
 643                              char *extra_args, int buflen)
 644 {
 645         const char *end = extra_args + buflen;
 646         struct strbuf git_protocol = STRBUF_INIT;
 647
 648         /* First look for the host argument */
 649         extra_args = parse_host_arg(hi, extra_args, buflen);
 650
 651         /* Look for additional arguments places after a second NUL byte */
 652         for (; extra_args < end; extra_args += strlen(extra_args) + 1) {
 653                 const char *arg = extra_args;
 654
 655                 /*
 656                  * Parse the extra arguments, adding most to 'git_protocol'
 657                  * which will be used to set the 'GIT_PROTOCOL' envvar in the
 658                  * service that will be run.
 659                  *
 660                  * If there ends up being a particular arg in the future that
 661                  * git-daemon needs to parse specifically (like the 'host' arg)
 662                  * then it can be parsed here and not added to 'git_protocol'.
 663                  */
 664                 if (*arg) {
 665                         if (git_protocol.len > 0)
 666                                 strbuf_addch(&git_protocol, ':');
 667                         strbuf_addstr(&git_protocol, arg);
 668                 }
 669         }
 670
 671         if (git_protocol.len > 0) {
 672                 loginfo("Extended attribute \"protocol\": %s", git_protocol.buf);
 673                 strvec_pushf(env, GIT_PROTOCOL_ENVIRONMENT "=%s",
 674                              git_protocol.buf);
 675         }
 676         strbuf_release(&git_protocol);
 677 }
 678
 679 /*
 680  * Locate canonical hostname and its IP address.
 681  */
 682 static void lookup_hostname(struct hostinfo *hi)
 683 {
 684         if (!hi->hostname_lookup_done && hi->hostname.len) {
 685 #ifndef NO_IPV6
 686                 struct addrinfo hints;
 687                 struct addrinfo *ai;
 688                 int gai;
 689                 static char addrbuf[HOST_NAME_MAX + 1];
 690
 691                 memset(&hints, 0, sizeof(hints));
 692                 hints.ai_flags = AI_CANONNAME;
 693
 694                 gai = getaddrinfo(hi->hostname.buf, NULL, &hints, &ai);
 695                 if (!gai) {
 696                         struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 697
 698                         inet_ntop(AF_INET, &sin_addr->sin_addr,
 699                                   addrbuf, sizeof(addrbuf));
 700                         strbuf_addstr(&hi->ip_address, addrbuf);
 701
 702                         if (ai->ai_canonname)
 703                                 sanitize_client(&hi->canon_hostname,
 704                                                 ai->ai_canonname);
 705                         else
 706                                 strbuf_addbuf(&hi->canon_hostname,
 707                                               &hi->ip_address);
 708
 709                         freeaddrinfo(ai);
 710                 }
 711 #else
 712                 struct hostent *hent;
 713                 struct sockaddr_in sa;
 714                 char **ap;
 715                 static char addrbuf[HOST_NAME_MAX + 1];
 716
 717                 hent = gethostbyname(hi->hostname.buf);
 718                 if (hent) {
 719                         ap = hent->h_addr_list;
 720                         memset(&sa, 0, sizeof sa);
 721                         sa.sin_family = hent->h_addrtype;
 722                         sa.sin_port = htons(0);
 723                         memcpy(&sa.sin_addr, *ap, hent->h_length);
 724
 725                         inet_ntop(hent->h_addrtype, &sa.sin_addr,
 726                                   addrbuf, sizeof(addrbuf));
 727
 728                         sanitize_client(&hi->canon_hostname, hent->h_name);
 729                         strbuf_addstr(&hi->ip_address, addrbuf);
 730                 }
 731 #endif
 732                 hi->hostname_lookup_done = 1;
 733         }
 734 }
 735
 736 static void hostinfo_clear(struct hostinfo *hi)
 737 {
 738         strbuf_release(&hi->hostname);
 739         strbuf_release(&hi->canon_hostname);
 740         strbuf_release(&hi->ip_address);
 741         strbuf_release(&hi->tcp_port);
 742 }
 743
 744 static void set_keep_alive(int sockfd)
 745 {
 746         int ka = 1;
 747
 748         if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0) {
 749                 if (errno != ENOTSOCK)
 750                         logerror("unable to set SO_KEEPALIVE on socket: %s",
 751                                 strerror(errno));
 752         }
 753 }
 754
 755 static int execute(void)
 756 {
 757         char *line = packet_buffer;
 758         int pktlen, len, i;
 759         char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
 760         struct hostinfo hi = HOSTINFO_INIT;
 761         struct strvec env = STRVEC_INIT;
 762
 763         if (addr)
 764                 loginfo("Connection from %s:%s", addr, port);
 765
 766         set_keep_alive(0);
 767         alarm(init_timeout ? init_timeout : timeout);
 768         pktlen = packet_read(0, packet_buffer, sizeof(packet_buffer), 0);
 769         alarm(0);
 770
 771         len = strlen(line);
 772         if (len && line[len-1] == '\n')
 773                 line[len-1] = 0;
 774
 775         /* parse additional args hidden behind a NUL byte */
 776         if (len != pktlen)
 777                 parse_extra_args(&hi, &env, line + len + 1, pktlen - len - 1);
 778
 779         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 780                 struct daemon_service *s = &(daemon_service[i]);
 781                 const char *arg;
 782
 783                 if (skip_prefix(line, "git-", &arg) &&
 784                     skip_prefix(arg, s->name, &arg) &&
 785                     *arg++ == ' ') {
 786                         /*
 787                          * Note: The directory here is probably context sensitive,
 788                          * and might depend on the actual service being performed.
 789                          */
 790                         int rc = run_service(arg, s, &hi, &env);
 791                         hostinfo_clear(&hi);
 792                         strvec_clear(&env);
 793                         return rc;
 794                 }
 795         }
 796
 797         hostinfo_clear(&hi);
 798         strvec_clear(&env);
 799         logerror("Protocol error: '%s'", line);
 800         return -1;
 801 }
 802
 803 static int addrcmp(const struct sockaddr_storage *s1,
 804     const struct sockaddr_storage *s2)
 805 {
 806         const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 807         const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 808
 809         if (sa1->sa_family != sa2->sa_family)
 810                 return sa1->sa_family - sa2->sa_family;
 811         if (sa1->sa_family == AF_INET)
 812                 return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 813                     &((struct sockaddr_in *)s2)->sin_addr,
 814                     sizeof(struct in_addr));
 815 #ifndef NO_IPV6
 816         if (sa1->sa_family == AF_INET6)
 817                 return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 818                     &((struct sockaddr_in6 *)s2)->sin6_addr,
 819                     sizeof(struct in6_addr));
 820 #endif
 821         return 0;
 822 }
 823
 824 static int max_connections = 32;
 825
 826 static unsigned int live_children;
 827
 828 static struct child {
 829         struct child *next;
 830         struct child_process cld;
 831         struct sockaddr_storage address;
 832 } *firstborn;
 833
 834 static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
 835 {
 836         struct child *newborn, **cradle;
 837
 838         CALLOC_ARRAY(newborn, 1);
 839         live_children++;
 840         memcpy(&newborn->cld, cld, sizeof(*cld));
 841         memcpy(&newborn->address, addr, addrlen);
 842         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 843                 if (!addrcmp(&(*cradle)->address, &newborn->address))
 844                         break;
 845         newborn->next = *cradle;
 846         *cradle = newborn;
 847 }
 848
 849 /*
 850  * This gets called if the number of connections grows
 851  * past "max_connections".
 852  *
 853  * We kill the newest connection from a duplicate IP.
 854  */
 855 static void kill_some_child(void)
 856 {
 857         const struct child *blanket, *next;
 858
 859         if (!(blanket = firstborn))
 860                 return;
 861
 862         for (; (next = blanket->next); blanket = next)
 863                 if (!addrcmp(&blanket->address, &next->address)) {
 864                         kill(blanket->cld.pid, SIGTERM);
 865                         break;
 866                 }
 867 }
 868
 869 static void check_dead_children(void)
 870 {
 871         int status;
 872         pid_t pid;
 873
 874         struct child **cradle, *blanket;
 875         for (cradle = &firstborn; (blanket = *cradle);)
 876                 if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
 877                         const char *dead = "";
 878                         if (status)
 879                                 dead = " (with error)";
 880                         loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 881
 882                         /* remove the child */
 883                         *cradle = blanket->next;
 884                         live_children--;
 885                         child_process_clear(&blanket->cld);
 886                         free(blanket);
 887                 } else
 888                         cradle = &blanket->next;
 889 }
 890
 891 static struct strvec cld_argv = STRVEC_INIT;
 892 static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 893 {
 894         struct child_process cld = CHILD_PROCESS_INIT;
 895
 896         if (max_connections && live_children >= max_connections) {
 897                 kill_some_child();
 898                 sleep(1);  /* give it some time to die */
 899                 check_dead_children();
 900                 if (live_children >= max_connections) {
 901                         close(incoming);
 902                         logerror("Too many children, dropping connection");
 903                         return;
 904                 }
 905         }
 906
 907         if (addr->sa_family == AF_INET) {
 908                 char buf[128] = "";
 909                 struct sockaddr_in *sin_addr = (void *) addr;
 910                 inet_ntop(addr->sa_family, &sin_addr->sin_addr, buf, sizeof(buf));
 911                 strvec_pushf(&cld.env_array, "REMOTE_ADDR=%s", buf);
 912                 strvec_pushf(&cld.env_array, "REMOTE_PORT=%d",
 913                              ntohs(sin_addr->sin_port));
 914 #ifndef NO_IPV6
 915         } else if (addr->sa_family == AF_INET6) {
 916                 char buf[128] = "";
 917                 struct sockaddr_in6 *sin6_addr = (void *) addr;
 918                 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(buf));
 919                 strvec_pushf(&cld.env_array, "REMOTE_ADDR=[%s]", buf);
 920                 strvec_pushf(&cld.env_array, "REMOTE_PORT=%d",
 921                              ntohs(sin6_addr->sin6_port));
 922 #endif
 923         }
 924
 925         cld.argv = cld_argv.v;
 926         cld.in = incoming;
 927         cld.out = dup(incoming);
 928
 929         if (start_command(&cld))
 930                 logerror("unable to fork");
 931         else
 932                 add_child(&cld, addr, addrlen);
 933 }
 934
 935 static void child_handler(int signo)
 936 {
 937         /*
 938          * Otherwise empty handler because systemcalls will get interrupted
 939          * upon signal receipt
 940          * SysV needs the handler to be rearmed
 941          */
 942         signal(SIGCHLD, child_handler);
 943 }
 944
 945 static int set_reuse_addr(int sockfd)
 946 {
 947         int on = 1;
 948
 949         if (!reuseaddr)
 950                 return 0;
 951         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 952                           &on, sizeof(on));
 953 }
 954
 955 struct socketlist {
 956         int *list;
 957         size_t nr;
 958         size_t alloc;
 959 };
 960
 961 static const char *ip2str(int family, struct sockaddr *sin, socklen_t len)
 962 {
 963 #ifdef NO_IPV6
 964         static char ip[INET_ADDRSTRLEN];
 965 #else
 966         static char ip[INET6_ADDRSTRLEN];
 967 #endif
 968
 969         switch (family) {
 970 #ifndef NO_IPV6
 971         case AF_INET6:
 972                 inet_ntop(family, &((struct sockaddr_in6*)sin)->sin6_addr, ip, len);
 973                 break;
 974 #endif
 975         case AF_INET:
 976                 inet_ntop(family, &((struct sockaddr_in*)sin)->sin_addr, ip, len);
 977                 break;
 978         default:
 979                 xsnprintf(ip, sizeof(ip), "<unknown>");
 980         }
 981         return ip;
 982 }
 983
 984 #ifndef NO_IPV6
 985
 986 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 987 {
 988         int socknum = 0;
 989         char pbuf[NI_MAXSERV];
 990         struct addrinfo hints, *ai0, *ai;
 991         int gai;
 992         long flags;
 993
 994         xsnprintf(pbuf, sizeof(pbuf), "%d", listen_port);
 995         memset(&hints, 0, sizeof(hints));
 996         hints.ai_family = AF_UNSPEC;
 997         hints.ai_socktype = SOCK_STREAM;
 998         hints.ai_protocol = IPPROTO_TCP;
 999         hints.ai_flags = AI_PASSIVE;
1000
1001         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
1002         if (gai) {
1003                 logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
1004                 return 0;
1005         }
1006
1007         for (ai = ai0; ai; ai = ai->ai_next) {
1008                 int sockfd;
1009
1010                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
1011                 if (sockfd < 0)
1012                         continue;
1013                 if (sockfd >= FD_SETSIZE) {
1014                         logerror("Socket descriptor too large");
1015                         close(sockfd);
1016                         continue;
1017                 }
1018
1019 #ifdef IPV6_V6ONLY
1020                 if (ai->ai_family == AF_INET6) {
1021                         int on = 1;
1022                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
1023                                    &on, sizeof(on));
1024                         /* Note: error is not fatal */
1025                 }
1026 #endif
1027
1028                 if (set_reuse_addr(sockfd)) {
1029                         logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
1030                         close(sockfd);
1031                         continue;
1032                 }
1033
1034                 set_keep_alive(sockfd);
1035
1036                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
1037                         logerror("Could not bind to %s: %s",
1038                                  ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
1039                                  strerror(errno));
1040                         close(sockfd);
1041                         continue;       /* not fatal */
1042                 }
1043                 if (listen(sockfd, 5) < 0) {
1044                         logerror("Could not listen to %s: %s",
1045                                  ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
1046                                  strerror(errno));
1047                         close(sockfd);
1048                         continue;       /* not fatal */
1049                 }
1050
1051                 flags = fcntl(sockfd, F_GETFD, 0);
1052                 if (flags >= 0)
1053                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
1054
1055                 ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
1056                 socklist->list[socklist->nr++] = sockfd;
1057                 socknum++;
1058         }
1059
1060         freeaddrinfo(ai0);
1061
1062         return socknum;
1063 }
1064
1065 #else /* NO_IPV6 */
1066
1067 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
1068 {
1069         struct sockaddr_in sin;
1070         int sockfd;
1071         long flags;
1072
1073         memset(&sin, 0, sizeof sin);
1074         sin.sin_family = AF_INET;
1075         sin.sin_port = htons(listen_port);
1076
1077         if (listen_addr) {
1078                 /* Well, host better be an IP address here. */
1079                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
1080                         return 0;
1081         } else {
1082                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
1083         }
1084
1085         sockfd = socket(AF_INET, SOCK_STREAM, 0);
1086         if (sockfd < 0)
1087                 return 0;
1088
1089         if (set_reuse_addr(sockfd)) {
1090                 logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
1091                 close(sockfd);
1092                 return 0;
1093         }
1094
1095         set_keep_alive(sockfd);
1096
1097         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
1098                 logerror("Could not bind to %s: %s",
1099                          ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
1100                          strerror(errno));
1101                 close(sockfd);
1102                 return 0;
1103         }
1104
1105         if (listen(sockfd, 5) < 0) {
1106                 logerror("Could not listen to %s: %s",
1107                          ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
1108                          strerror(errno));
1109                 close(sockfd);
1110                 return 0;
1111         }
1112
1113         flags = fcntl(sockfd, F_GETFD, 0);
1114         if (flags >= 0)
1115                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
1116
1117         ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
1118         socklist->list[socklist->nr++] = sockfd;
1119         return 1;
1120 }
1121
1122 #endif
1123
1124 static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
1125 {
1126         if (!listen_addr->nr)
1127                 setup_named_sock(NULL, listen_port, socklist);
1128         else {
1129                 int i, socknum;
1130                 for (i = 0; i < listen_addr->nr; i++) {
1131                         socknum = setup_named_sock(listen_addr->items[i].string,
1132                                                    listen_port, socklist);
1133
1134                         if (socknum == 0)
1135                                 logerror("unable to allocate any listen sockets for host %s on port %u",
1136                                          listen_addr->items[i].string, listen_port);
1137                 }
1138         }
1139 }
1140
1141 static int service_loop(struct socketlist *socklist)
1142 {
1143         struct pollfd *pfd;
1144         int i;
1145
1146         CALLOC_ARRAY(pfd, socklist->nr);
1147
1148         for (i = 0; i < socklist->nr; i++) {
1149                 pfd[i].fd = socklist->list[i];
1150                 pfd[i].events = POLLIN;
1151         }
1152
1153         signal(SIGCHLD, child_handler);
1154
1155         for (;;) {
1156                 int i;
1157
1158                 check_dead_children();
1159
1160                 if (poll(pfd, socklist->nr, -1) < 0) {
1161                         if (errno != EINTR) {
1162                                 logerror("Poll failed, resuming: %s",
1163                                       strerror(errno));
1164                                 sleep(1);
1165                         }
1166                         continue;
1167                 }
1168
1169                 for (i = 0; i < socklist->nr; i++) {
1170                         if (pfd[i].revents & POLLIN) {
1171                                 union {
1172                                         struct sockaddr sa;
1173                                         struct sockaddr_in sai;
1174 #ifndef NO_IPV6
1175                                         struct sockaddr_in6 sai6;
1176 #endif
1177                                 } ss;
1178                                 socklen_t sslen = sizeof(ss);
1179                                 int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
1180                                 if (incoming < 0) {
1181                                         switch (errno) {
1182                                         case EAGAIN:
1183                                         case EINTR:
1184                                         case ECONNABORTED:
1185                                                 continue;
1186                                         default:
1187                                                 die_errno("accept returned");
1188                                         }
1189                                 }
1190                                 handle(incoming, &ss.sa, sslen);
1191                         }
1192                 }
1193         }
1194 }
1195
1196 #ifdef NO_POSIX_GOODIES
1197
1198 struct credentials;
1199
1200 static void drop_privileges(struct credentials *cred)
1201 {
1202         /* nothing */
1203 }
1204
1205 static struct credentials *prepare_credentials(const char *user_name,
1206     const char *group_name)
1207 {
1208         die("--user not supported on this platform");
1209 }
1210
1211 #else
1212
1213 struct credentials {
1214         struct passwd *pass;
1215         gid_t gid;
1216 };
1217
1218 static void drop_privileges(struct credentials *cred)
1219 {
1220         if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
1221             setgid (cred->gid) || setuid(cred->pass->pw_uid)))
1222                 die("cannot drop privileges");
1223 }
1224
1225 static struct credentials *prepare_credentials(const char *user_name,
1226     const char *group_name)
1227 {
1228         static struct credentials c;
1229
1230         c.pass = getpwnam(user_name);
1231         if (!c.pass)
1232                 die("user not found - %s", user_name);
1233
1234         if (!group_name)
1235                 c.gid = c.pass->pw_gid;
1236         else {
1237                 struct group *group = getgrnam(group_name);
1238                 if (!group)
1239                         die("group not found - %s", group_name);
1240
1241                 c.gid = group->gr_gid;
1242         }
1243
1244         return &c;
1245 }
1246 #endif
1247
1248 static int serve(struct string_list *listen_addr, int listen_port,
1249     struct credentials *cred)
1250 {
1251         struct socketlist socklist = { NULL, 0, 0 };
1252
1253         socksetup(listen_addr, listen_port, &socklist);
1254         if (socklist.nr == 0)
1255                 die("unable to allocate any listen sockets on port %u",
1256                     listen_port);
1257
1258         drop_privileges(cred);
1259
1260         loginfo("Ready to rumble");
1261
1262         return service_loop(&socklist);
1263 }
1264
1265 int cmd_main(int argc, const char **argv)
1266 {
1267         int listen_port = 0;
1268         struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1269         int serve_mode = 0, inetd_mode = 0;
1270         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1271         int detach = 0;
1272         struct credentials *cred = NULL;
1273         int i;
1274
1275         for (i = 1; i < argc; i++) {
1276                 const char *arg = argv[i];
1277                 const char *v;
1278
1279                 if (skip_prefix(arg, "--listen=", &v)) {
1280                         string_list_append(&listen_addr, xstrdup_tolower(v));
1281                         continue;
1282                 }
1283                 if (skip_prefix(arg, "--port=", &v)) {
1284                         char *end;
1285                         unsigned long n;
1286                         n = strtoul(v, &end, 0);
1287                         if (*v && !*end) {
1288                                 listen_port = n;
1289                                 continue;
1290                         }
1291                 }
1292                 if (!strcmp(arg, "--serve")) {
1293                         serve_mode = 1;
1294                         continue;
1295                 }
1296                 if (!strcmp(arg, "--inetd")) {
1297                         inetd_mode = 1;
1298                         continue;
1299                 }
1300                 if (!strcmp(arg, "--verbose")) {
1301                         verbose = 1;
1302                         continue;
1303                 }
1304                 if (!strcmp(arg, "--syslog")) {
1305                         log_destination = LOG_DESTINATION_SYSLOG;
1306                         continue;
1307                 }
1308                 if (skip_prefix(arg, "--log-destination=", &v)) {
1309                         if (!strcmp(v, "syslog")) {
1310                                 log_destination = LOG_DESTINATION_SYSLOG;
1311                                 continue;
1312                         } else if (!strcmp(v, "stderr")) {
1313                                 log_destination = LOG_DESTINATION_STDERR;
1314                                 continue;
1315                         } else if (!strcmp(v, "none")) {
1316                                 log_destination = LOG_DESTINATION_NONE;
1317                                 continue;
1318                         } else
1319                                 die("unknown log destination '%s'", v);
1320                 }
1321                 if (!strcmp(arg, "--export-all")) {
1322                         export_all_trees = 1;
1323                         continue;
1324                 }
1325                 if (skip_prefix(arg, "--access-hook=", &v)) {
1326                         access_hook = v;
1327                         continue;
1328                 }
1329                 if (skip_prefix(arg, "--timeout=", &v)) {
1330                         timeout = atoi(v);
1331                         continue;
1332                 }
1333                 if (skip_prefix(arg, "--init-timeout=", &v)) {
1334                         init_timeout = atoi(v);
1335                         continue;
1336                 }
1337                 if (skip_prefix(arg, "--max-connections=", &v)) {
1338                         max_connections = atoi(v);
1339                         if (max_connections < 0)
1340                                 max_connections = 0;            /* unlimited */
1341                         continue;
1342                 }
1343                 if (!strcmp(arg, "--strict-paths")) {
1344                         strict_paths = 1;
1345                         continue;
1346                 }
1347                 if (skip_prefix(arg, "--base-path=", &v)) {
1348                         base_path = v;
1349                         continue;
1350                 }
1351                 if (!strcmp(arg, "--base-path-relaxed")) {
1352                         base_path_relaxed = 1;
1353                         continue;
1354                 }
1355                 if (skip_prefix(arg, "--interpolated-path=", &v)) {
1356                         interpolated_path = v;
1357                         continue;
1358                 }
1359                 if (!strcmp(arg, "--reuseaddr")) {
1360                         reuseaddr = 1;
1361                         continue;
1362                 }
1363                 if (!strcmp(arg, "--user-path")) {
1364                         user_path = "";
1365                         continue;
1366                 }
1367                 if (skip_prefix(arg, "--user-path=", &v)) {
1368                         user_path = v;
1369                         continue;
1370                 }
1371                 if (skip_prefix(arg, "--pid-file=", &v)) {
1372                         pid_file = v;
1373                         continue;
1374                 }
1375                 if (!strcmp(arg, "--detach")) {
1376                         detach = 1;
1377                         continue;
1378                 }
1379                 if (skip_prefix(arg, "--user=", &v)) {
1380                         user_name = v;
1381                         continue;
1382                 }
1383                 if (skip_prefix(arg, "--group=", &v)) {
1384                         group_name = v;
1385                         continue;
1386                 }
1387                 if (skip_prefix(arg, "--enable=", &v)) {
1388                         enable_service(v, 1);
1389                         continue;
1390                 }
1391                 if (skip_prefix(arg, "--disable=", &v)) {
1392                         enable_service(v, 0);
1393                         continue;
1394                 }
1395                 if (skip_prefix(arg, "--allow-override=", &v)) {
1396                         make_service_overridable(v, 1);
1397                         continue;
1398                 }
1399                 if (skip_prefix(arg, "--forbid-override=", &v)) {
1400                         make_service_overridable(v, 0);
1401                         continue;
1402                 }
1403                 if (!strcmp(arg, "--informative-errors")) {
1404                         informative_errors = 1;
1405                         continue;
1406                 }
1407                 if (!strcmp(arg, "--no-informative-errors")) {
1408                         informative_errors = 0;
1409                         continue;
1410                 }
1411                 if (!strcmp(arg, "--")) {
1412                         ok_paths = &argv[i+1];
1413                         break;
1414                 } else if (arg[0] != '-') {
1415                         ok_paths = &argv[i];
1416                         break;
1417                 }
1418
1419                 usage(daemon_usage);
1420         }
1421
1422         if (log_destination == LOG_DESTINATION_UNSET) {
1423                 if (inetd_mode || detach)
1424                         log_destination = LOG_DESTINATION_SYSLOG;
1425                 else
1426                         log_destination = LOG_DESTINATION_STDERR;
1427         }
1428
1429         if (log_destination == LOG_DESTINATION_SYSLOG) {
1430                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1431                 set_die_routine(daemon_die);
1432         } else
1433                 /* avoid splitting a message in the middle */
1434                 setvbuf(stderr, NULL, _IOFBF, 4096);
1435
1436         if (inetd_mode && (detach || group_name || user_name))
1437                 die("--detach, --user and --group are incompatible with --inetd");
1438
1439         if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1440                 die("--listen= and --port= are incompatible with --inetd");
1441         else if (listen_port == 0)
1442                 listen_port = DEFAULT_GIT_PORT;
1443
1444         if (group_name && !user_name)
1445                 die("--group supplied without --user");
1446
1447         if (user_name)
1448                 cred = prepare_credentials(user_name, group_name);
1449
1450         if (strict_paths && (!ok_paths || !*ok_paths))
1451                 die("option --strict-paths requires a whitelist");
1452
1453         if (base_path && !is_directory(base_path))
1454                 die("base-path '%s' does not exist or is not a directory",
1455                     base_path);
1456
1457         if (log_destination != LOG_DESTINATION_STDERR) {
1458                 if (!freopen("/dev/null", "w", stderr))
1459                         die_errno("failed to redirect stderr to /dev/null");
1460         }
1461
1462         if (inetd_mode || serve_mode)
1463                 return execute();
1464
1465         if (detach) {
1466                 if (daemonize())
1467                         die("--detach not supported on this platform");
1468         }
1469
1470         if (pid_file)
1471                 write_file(pid_file, "%"PRIuMAX, (uintmax_t) getpid());
1472
1473         /* prepare argv for serving-processes */
1474         strvec_push(&cld_argv, argv[0]); /* git-daemon */
1475         strvec_push(&cld_argv, "--serve");
1476         for (i = 1; i < argc; ++i)
1477                 strvec_push(&cld_argv, argv[i]);
1478
1479         return serve(&listen_addr, listen_port, cred);
1480 }