daemon.c

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