daemon.c

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