daemon.c

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