daemon.c

   1 #include "cache.h"
   2 #include "abspath.h"
   3 #include "alloc.h"
   4 #include "config.h"
   5 #include "environment.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 #include "wrapper.h"
  13
  14 #ifdef NO_INITGROUPS
  15 #define initgroups(x, y) (0) /* nothing */
  16 #endif
  17
  18 static enum log_destination {
  19         LOG_DESTINATION_UNSET = -1,
  20         LOG_DESTINATION_NONE = 0,
  21         LOG_DESTINATION_STDERR = 1,
  22         LOG_DESTINATION_SYSLOG = 2,
  23 } log_destination = LOG_DESTINATION_UNSET;
  24 static int verbose;
  25 static int reuseaddr;
  26 static int informative_errors;
  27
  28 static const char daemon_usage[] =
  29 "git daemon [--verbose] [--syslog] [--export-all]\n"
  30 "           [--timeout=<n>] [--init-timeout=<n>] [--max-connections=<n>]\n"
  31 "           [--strict-paths] [--base-path=<path>] [--base-path-relaxed]\n"
  32 "           [--user-path | --user-path=<path>]\n"
  33 "           [--interpolated-path=<path>]\n"
  34 "           [--reuseaddr] [--pid-file=<file>]\n"
  35 "           [--(enable|disable|allow-override|forbid-override)=<service>]\n"
  36 "           [--access-hook=<path>]\n"
  37 "           [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
  38 "                      [--detach] [--user=<user> [--group=<group>]]\n"
  39 "           [--log-destination=(stderr|syslog|none)]\n"
  40 "           [<directory>...]";
  41
  42 /* List of acceptable pathname prefixes */
  43 static const char **ok_paths;
  44 static int strict_paths;
  45
  46 /* If this is set, git-daemon-export-ok is not required */
  47 static int export_all_trees;
  48
  49 /* Take all paths relative to this one if non-NULL */
  50 static const char *base_path;
  51 static const char *interpolated_path;
  52 static int base_path_relaxed;
  53
  54 /* If defined, ~user notation is allowed and the string is inserted
  55  * after ~user/.  E.g. a request to git://host/~alice/frotz would
  56  * go to /home/alice/pub_git/frotz with --user-path=pub_git.
  57  */
  58 static const char *user_path;
  59
  60 /* Timeout, and initial timeout */
  61 static unsigned int timeout;
  62 static unsigned int init_timeout;
  63
  64 struct hostinfo {
  65         struct strbuf hostname;
  66         struct strbuf canon_hostname;
  67         struct strbuf ip_address;
  68         struct strbuf tcp_port;
  69         unsigned int hostname_lookup_done:1;
  70         unsigned int saw_extended_args:1;
  71 };
  72 #define HOSTINFO_INIT { \
  73         .hostname = STRBUF_INIT, \
  74         .canon_hostname = STRBUF_INIT, \
  75         .ip_address = STRBUF_INIT, \
  76         .tcp_port = STRBUF_INIT, \
  77 }
  78
  79 static void lookup_hostname(struct hostinfo *hi);
  80
  81 static const char *get_canon_hostname(struct hostinfo *hi)
  82 {
  83         lookup_hostname(hi);
  84         return hi->canon_hostname.buf;
  85 }
  86
  87 static const char *get_ip_address(struct hostinfo *hi)
  88 {
  89         lookup_hostname(hi);
  90         return hi->ip_address.buf;
  91 }
  92
  93 static void logreport(int priority, const char *err, va_list params)
  94 {
  95         switch (log_destination) {
  96         case LOG_DESTINATION_SYSLOG: {
  97                 char buf[1024];
  98                 vsnprintf(buf, sizeof(buf), err, params);
  99                 syslog(priority, "%s", buf);
 100                 break;
 101         }
 102         case LOG_DESTINATION_STDERR:
 103                 /*
 104                  * Since stderr is set to buffered mode, the
 105                  * logging of different processes will not overlap
 106                  * unless they overflow the (rather big) buffers.
 107                  */
 108                 fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
 109                 vfprintf(stderr, err, params);
 110                 fputc('\n', stderr);
 111                 fflush(stderr);
 112                 break;
 113         case LOG_DESTINATION_NONE:
 114                 break;
 115         case LOG_DESTINATION_UNSET:
 116                 BUG("log destination not initialized correctly");
 117         }
 118 }
 119
 120 __attribute__((format (printf, 1, 2)))
 121 static void logerror(const char *err, ...)
 122 {
 123         va_list params;
 124         va_start(params, err);
 125         logreport(LOG_ERR, err, params);
 126         va_end(params);
 127 }
 128
 129 __attribute__((format (printf, 1, 2)))
 130 static void loginfo(const char *err, ...)
 131 {
 132         va_list params;
 133         if (!verbose)
 134                 return;
 135         va_start(params, err);
 136         logreport(LOG_INFO, err, params);
 137         va_end(params);
 138 }
 139
 140 static void NORETURN daemon_die(const char *err, va_list params)
 141 {
 142         logreport(LOG_ERR, err, params);
 143         exit(1);
 144 }
 145
 146 struct expand_path_context {
 147         const char *directory;
 148         struct hostinfo *hostinfo;
 149 };
 150
 151 static size_t expand_path(struct strbuf *sb, const char *placeholder, void *ctx)
 152 {
 153         struct expand_path_context *context = ctx;
 154         struct hostinfo *hi = context->hostinfo;
 155
 156         switch (placeholder[0]) {
 157         case 'H':
 158                 strbuf_addbuf(sb, &hi->hostname);
 159                 return 1;
 160         case 'C':
 161                 if (placeholder[1] == 'H') {
 162                         strbuf_addstr(sb, get_canon_hostname(hi));
 163                         return 2;
 164                 }
 165                 break;
 166         case 'I':
 167                 if (placeholder[1] == 'P') {
 168                         strbuf_addstr(sb, get_ip_address(hi));
 169                         return 2;
 170                 }
 171                 break;
 172         case 'P':
 173                 strbuf_addbuf(sb, &hi->tcp_port);
 174                 return 1;
 175         case 'D':
 176                 strbuf_addstr(sb, context->directory);
 177                 return 1;
 178         }
 179         return 0;
 180 }
 181
 182 static const char *path_ok(const char *directory, struct hostinfo *hi)
 183 {
 184         static char rpath[PATH_MAX];
 185         static char interp_path[PATH_MAX];
 186         size_t rlen;
 187         const char *path;
 188         const char *dir;
 189
 190         dir = directory;
 191
 192         if (daemon_avoid_alias(dir)) {
 193                 logerror("'%s': aliased", dir);
 194                 return NULL;
 195         }
 196
 197         if (*dir == '~') {
 198                 if (!user_path) {
 199                         logerror("'%s': User-path not allowed", dir);
 200                         return NULL;
 201                 }
 202                 if (*user_path) {
 203                         /* Got either "~alice" or "~alice/foo";
 204                          * rewrite them to "~alice/%s" or
 205                          * "~alice/%s/foo".
 206                          */
 207                         int namlen, restlen = strlen(dir);
 208                         const char *slash = strchr(dir, '/');
 209                         if (!slash)
 210                                 slash = dir + restlen;
 211                         namlen = slash - dir;
 212                         restlen -= namlen;
 213                         loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
 214                         rlen = snprintf(rpath, sizeof(rpath), "%.*s/%s%.*s",
 215                                         namlen, dir, user_path, restlen, slash);
 216                         if (rlen >= sizeof(rpath)) {
 217                                 logerror("user-path too large: %s", rpath);
 218                                 return NULL;
 219                         }
 220                         dir = rpath;
 221                 }
 222         }
 223         else if (interpolated_path && hi->saw_extended_args) {
 224                 struct strbuf expanded_path = STRBUF_INIT;
 225                 struct expand_path_context context;
 226
 227                 context.directory = directory;
 228                 context.hostinfo = hi;
 229
 230                 if (*dir != '/') {
 231                         /* Allow only absolute */
 232                         logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 233                         return NULL;
 234                 }
 235
 236                 strbuf_expand(&expanded_path, interpolated_path,
 237                               expand_path, &context);
 238
 239                 rlen = strlcpy(interp_path, expanded_path.buf,
 240                                sizeof(interp_path));
 241                 strbuf_release(&expanded_path);
 242                 if (rlen >= sizeof(interp_path)) {
 243                         logerror("interpolated path too large: %s",
 244                                  interp_path);
 245                         return NULL;
 246                 }
 247
 248                 loginfo("Interpolated dir '%s'", interp_path);
 249
 250                 dir = interp_path;
 251         }
 252         else if (base_path) {
 253                 if (*dir != '/') {
 254                         /* Allow only absolute */
 255                         logerror("'%s': Non-absolute path denied (base-path active)", dir);
 256                         return NULL;
 257                 }
 258                 rlen = snprintf(rpath, sizeof(rpath), "%s%s", base_path, dir);
 259                 if (rlen >= sizeof(rpath)) {
 260                         logerror("base-path too large: %s", rpath);
 261                         return NULL;
 262                 }
 263                 dir = rpath;
 264         }
 265
 266         path = enter_repo(dir, strict_paths);
 267         if (!path && base_path && base_path_relaxed) {
 268                 /*
 269                  * if we fail and base_path_relaxed is enabled, try without
 270                  * prefixing the base path
 271                  */
 272                 dir = directory;
 273                 path = enter_repo(dir, strict_paths);
 274         }
 275
 276         if (!path) {
 277                 logerror("'%s' does not appear to be a git repository", dir);
 278                 return NULL;
 279         }
 280
 281         if ( ok_paths && *ok_paths ) {
 282                 const char **pp;
 283                 int pathlen = strlen(path);
 284
 285                 /* The validation is done on the paths after enter_repo
 286                  * appends optional {.git,.git/.git} and friends, but
 287                  * it does not use getcwd().  So if your /pub is
 288                  * a symlink to /mnt/pub, you can include /pub and
 289                  * do not have to say /mnt/pub.
 290                  * Do not say /pub/.
 291                  */
 292                 for ( pp = ok_paths ; *pp ; pp++ ) {
 293                         int len = strlen(*pp);
 294                         if (len <= pathlen &&
 295                             !memcmp(*pp, path, len) &&
 296                             (path[len] == '\0' ||
 297                              (!strict_paths && path[len] == '/')))
 298                                 return path;
 299                 }
 300         }
 301         else {
 302                 /* be backwards compatible */
 303                 if (!strict_paths)
 304                         return path;
 305         }
 306
 307         logerror("'%s': not in directory list", path);
 308         return NULL;            /* Fallthrough. Deny by default */
 309 }
 310
 311 typedef int (*daemon_service_fn)(const struct strvec *env);
 312 struct daemon_service {
 313         const char *name;
 314         const char *config_name;
 315         daemon_service_fn fn;
 316         int enabled;
 317         int overridable;
 318 };
 319
 320 static int daemon_error(const char *dir, const char *msg)
 321 {
 322         if (!informative_errors)
 323                 msg = "access denied or repository not exported";
 324         packet_write_fmt(1, "ERR %s: %s", msg, dir);
 325         return -1;
 326 }
 327
 328 static const char *access_hook;
 329
 330 static int run_access_hook(struct daemon_service *service, const char *dir,
 331                            const char *path, struct hostinfo *hi)
 332 {
 333         struct child_process child = CHILD_PROCESS_INIT;
 334         struct strbuf buf = STRBUF_INIT;
 335         char *eol;
 336         int seen_errors = 0;
 337
 338         strvec_push(&child.args, access_hook);
 339         strvec_push(&child.args, service->name);
 340         strvec_push(&child.args, path);
 341         strvec_push(&child.args, hi->hostname.buf);
 342         strvec_push(&child.args, get_canon_hostname(hi));
 343         strvec_push(&child.args, get_ip_address(hi));
 344         strvec_push(&child.args, hi->tcp_port.buf);
 345
 346         child.use_shell = 1;
 347         child.no_stdin = 1;
 348         child.no_stderr = 1;
 349         child.out = -1;
 350         if (start_command(&child)) {
 351                 logerror("daemon access hook '%s' failed to start",
 352                          access_hook);
 353                 goto error_return;
 354         }
 355         if (strbuf_read(&buf, child.out, 0) < 0) {
 356                 logerror("failed to read from pipe to daemon access hook '%s'",
 357                          access_hook);
 358                 strbuf_reset(&buf);
 359                 seen_errors = 1;
 360         }
 361         if (close(child.out) < 0) {
 362                 logerror("failed to close pipe to daemon access hook '%s'",
 363                          access_hook);
 364                 seen_errors = 1;
 365         }
 366         if (finish_command(&child))
 367                 seen_errors = 1;
 368
 369         if (!seen_errors) {
 370                 strbuf_release(&buf);
 371                 return 0;
 372         }
 373
 374 error_return:
 375         strbuf_ltrim(&buf);
 376         if (!buf.len)
 377                 strbuf_addstr(&buf, "service rejected");
 378         eol = strchr(buf.buf, '\n');
 379         if (eol)
 380                 *eol = '\0';
 381         errno = EACCES;
 382         daemon_error(dir, buf.buf);
 383         strbuf_release(&buf);
 384         return -1;
 385 }
 386
 387 static int run_service(const char *dir, struct daemon_service *service,
 388                        struct hostinfo *hi, const struct strvec *env)
 389 {
 390         const char *path;
 391         int enabled = service->enabled;
 392         struct strbuf var = STRBUF_INIT;
 393
 394         loginfo("Request %s for '%s'", service->name, dir);
 395
 396         if (!enabled && !service->overridable) {
 397                 logerror("'%s': service not enabled.", service->name);
 398                 errno = EACCES;
 399                 return daemon_error(dir, "service not enabled");
 400         }
 401
 402         if (!(path = path_ok(dir, hi)))
 403                 return daemon_error(dir, "no such repository");
 404
 405         /*
 406          * Security on the cheap.
 407          *
 408          * We want a readable HEAD, usable "objects" directory, and
 409          * a "git-daemon-export-ok" flag that says that the other side
 410          * is ok with us doing this.
 411          *
 412          * path_ok() uses enter_repo() and checks for included directories.
 413          * We only need to make sure the repository is exported.
 414          */
 415
 416         if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 417                 logerror("'%s': repository not exported.", path);
 418                 errno = EACCES;
 419                 return daemon_error(dir, "repository not exported");
 420         }
 421
 422         if (service->overridable) {
 423                 strbuf_addf(&var, "daemon.%s", service->config_name);
 424                 git_config_get_bool(var.buf, &enabled);
 425                 strbuf_release(&var);
 426         }
 427         if (!enabled) {
 428                 logerror("'%s': service not enabled for '%s'",
 429                          service->name, path);
 430                 errno = EACCES;
 431                 return daemon_error(dir, "service not enabled");
 432         }
 433
 434         /*
 435          * Optionally, a hook can choose to deny access to the
 436          * repository depending on the phase of the moon.
 437          */
 438         if (access_hook && run_access_hook(service, dir, path, hi))
 439                 return -1;
 440
 441         /*
 442          * We'll ignore SIGTERM from now on, we have a
 443          * good client.
 444          */
 445         signal(SIGTERM, SIG_IGN);
 446
 447         return service->fn(env);
 448 }
 449
 450 static void copy_to_log(int fd)
 451 {
 452         struct strbuf line = STRBUF_INIT;
 453         FILE *fp;
 454
 455         fp = fdopen(fd, "r");
 456         if (!fp) {
 457                 logerror("fdopen of error channel failed");
 458                 close(fd);
 459                 return;
 460         }
 461
 462         while (strbuf_getline_lf(&line, fp) != EOF) {
 463                 logerror("%s", line.buf);
 464                 strbuf_setlen(&line, 0);
 465         }
 466
 467         strbuf_release(&line);
 468         fclose(fp);
 469 }
 470
 471 static int run_service_command(struct child_process *cld)
 472 {
 473         strvec_push(&cld->args, ".");
 474         cld->git_cmd = 1;
 475         cld->err = -1;
 476         if (start_command(cld))
 477                 return -1;
 478
 479         close(0);
 480         close(1);
 481
 482         copy_to_log(cld->err);
 483
 484         return finish_command(cld);
 485 }
 486
 487 static int upload_pack(const struct strvec *env)
 488 {
 489         struct child_process cld = CHILD_PROCESS_INIT;
 490         strvec_pushl(&cld.args, "upload-pack", "--strict", NULL);
 491         strvec_pushf(&cld.args, "--timeout=%u", timeout);
 492
 493         strvec_pushv(&cld.env, env->v);
 494
 495         return run_service_command(&cld);
 496 }
 497
 498 static int upload_archive(const struct strvec *env)
 499 {
 500         struct child_process cld = CHILD_PROCESS_INIT;
 501         strvec_push(&cld.args, "upload-archive");
 502
 503         strvec_pushv(&cld.env, env->v);
 504
 505         return run_service_command(&cld);
 506 }
 507
 508 static int receive_pack(const struct strvec *env)
 509 {
 510         struct child_process cld = CHILD_PROCESS_INIT;
 511         strvec_push(&cld.args, "receive-pack");
 512
 513         strvec_pushv(&cld.env, env->v);
 514
 515         return run_service_command(&cld);
 516 }
 517
 518 static struct daemon_service daemon_service[] = {
 519         { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 520         { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 521         { "receive-pack", "receivepack", receive_pack, 0, 1 },
 522 };
 523
 524 static void enable_service(const char *name, int ena)
 525 {
 526         int i;
 527         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 528                 if (!strcmp(daemon_service[i].name, name)) {
 529                         daemon_service[i].enabled = ena;
 530                         return;
 531                 }
 532         }
 533         die("No such service %s", name);
 534 }
 535
 536 static void make_service_overridable(const char *name, int ena)
 537 {
 538         int i;
 539         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 540                 if (!strcmp(daemon_service[i].name, name)) {
 541                         daemon_service[i].overridable = ena;
 542                         return;
 543                 }
 544         }
 545         die("No such service %s", name);
 546 }
 547
 548 static void parse_host_and_port(char *hostport, char **host,
 549         char **port)
 550 {
 551         if (*hostport == '[') {
 552                 char *end;
 553
 554                 end = strchr(hostport, ']');
 555                 if (!end)
 556                         die("Invalid request ('[' without ']')");
 557                 *end = '\0';
 558                 *host = hostport + 1;
 559                 if (!end[1])
 560                         *port = NULL;
 561                 else if (end[1] == ':')
 562                         *port = end + 2;
 563                 else
 564                         die("Garbage after end of host part");
 565         } else {
 566                 *host = hostport;
 567                 *port = strrchr(hostport, ':');
 568                 if (*port) {
 569                         **port = '\0';
 570                         ++*port;
 571                 }
 572         }
 573 }
 574
 575 /*
 576  * Sanitize a string from the client so that it's OK to be inserted into a
 577  * filesystem path. Specifically, we disallow directory separators, runs
 578  * of "..", and trailing and leading dots, which means that the client
 579  * cannot escape our base path via ".." traversal.
 580  */
 581 static void sanitize_client(struct strbuf *out, const char *in)
 582 {
 583         for (; *in; in++) {
 584                 if (is_dir_sep(*in))
 585                         continue;
 586                 if (*in == '.' && (!out->len || out->buf[out->len - 1] == '.'))
 587                         continue;
 588                 strbuf_addch(out, *in);
 589         }
 590
 591         while (out->len && out->buf[out->len - 1] == '.')
 592                 strbuf_setlen(out, out->len - 1);
 593 }
 594
 595 /*
 596  * Like sanitize_client, but we also perform any canonicalization
 597  * to make life easier on the admin.
 598  */
 599 static void canonicalize_client(struct strbuf *out, const char *in)
 600 {
 601         sanitize_client(out, in);
 602         strbuf_tolower(out);
 603 }
 604
 605 /*
 606  * Read the host as supplied by the client connection.
 607  *
 608  * Returns a pointer to the character after the NUL byte terminating the host
 609  * argument, or 'extra_args' if there is no host argument.
 610  */
 611 static char *parse_host_arg(struct hostinfo *hi, char *extra_args, int buflen)
 612 {
 613         char *val;
 614         int vallen;
 615         char *end = extra_args + buflen;
 616
 617         if (extra_args < end && *extra_args) {
 618                 hi->saw_extended_args = 1;
 619                 if (strncasecmp("host=", extra_args, 5) == 0) {
 620                         val = extra_args + 5;
 621                         vallen = strlen(val) + 1;
 622                         loginfo("Extended attribute \"host\": %s", val);
 623                         if (*val) {
 624                                 /* Split <host>:<port> at colon. */
 625                                 char *host;
 626                                 char *port;
 627                                 parse_host_and_port(val, &host, &port);
 628                                 if (port)
 629                                         sanitize_client(&hi->tcp_port, port);
 630                                 canonicalize_client(&hi->hostname, host);
 631                                 hi->hostname_lookup_done = 0;
 632                         }
 633
 634                         /* On to the next one */
 635                         extra_args = val + vallen;
 636                 }
 637                 if (extra_args < end && *extra_args)
 638                         die("Invalid request");
 639         }
 640
 641         return extra_args;
 642 }
 643
 644 static void parse_extra_args(struct hostinfo *hi, struct strvec *env,
 645                              char *extra_args, int buflen)
 646 {
 647         const char *end = extra_args + buflen;
 648         struct strbuf git_protocol = STRBUF_INIT;
 649
 650         /* First look for the host argument */
 651         extra_args = parse_host_arg(hi, extra_args, buflen);
 652
 653         /* Look for additional arguments places after a second NUL byte */
 654         for (; extra_args < end; extra_args += strlen(extra_args) + 1) {
 655                 const char *arg = extra_args;
 656
 657                 /*
 658                  * Parse the extra arguments, adding most to 'git_protocol'
 659                  * which will be used to set the 'GIT_PROTOCOL' envvar in the
 660                  * service that will be run.
 661                  *
 662                  * If there ends up being a particular arg in the future that
 663                  * git-daemon needs to parse specifically (like the 'host' arg)
 664                  * then it can be parsed here and not added to 'git_protocol'.
 665                  */
 666                 if (*arg) {
 667                         if (git_protocol.len > 0)
 668                                 strbuf_addch(&git_protocol, ':');
 669                         strbuf_addstr(&git_protocol, arg);
 670                 }
 671         }
 672
 673         if (git_protocol.len > 0) {
 674                 loginfo("Extended attribute \"protocol\": %s", git_protocol.buf);
 675                 strvec_pushf(env, GIT_PROTOCOL_ENVIRONMENT "=%s",
 676                              git_protocol.buf);
 677         }
 678         strbuf_release(&git_protocol);
 679 }
 680
 681 /*
 682  * Locate canonical hostname and its IP address.
 683  */
 684 static void lookup_hostname(struct hostinfo *hi)
 685 {
 686         if (!hi->hostname_lookup_done && hi->hostname.len) {
 687 #ifndef NO_IPV6
 688                 struct addrinfo hints;
 689                 struct addrinfo *ai;
 690                 int gai;
 691                 static char addrbuf[HOST_NAME_MAX + 1];
 692
 693                 memset(&hints, 0, sizeof(hints));
 694                 hints.ai_flags = AI_CANONNAME;
 695
 696                 gai = getaddrinfo(hi->hostname.buf, NULL, &hints, &ai);
 697                 if (!gai) {
 698                         struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 699
 700                         inet_ntop(AF_INET, &sin_addr->sin_addr,
 701                                   addrbuf, sizeof(addrbuf));
 702                         strbuf_addstr(&hi->ip_address, addrbuf);
 703
 704                         if (ai->ai_canonname)
 705                                 sanitize_client(&hi->canon_hostname,
 706                                                 ai->ai_canonname);
 707                         else
 708                                 strbuf_addbuf(&hi->canon_hostname,
 709                                               &hi->ip_address);
 710
 711                         freeaddrinfo(ai);
 712                 }
 713 #else
 714                 struct hostent *hent;
 715                 struct sockaddr_in sa;
 716                 char **ap;
 717                 static char addrbuf[HOST_NAME_MAX + 1];
 718
 719                 hent = gethostbyname(hi->hostname.buf);
 720                 if (hent) {
 721                         ap = hent->h_addr_list;
 722                         memset(&sa, 0, sizeof sa);
 723                         sa.sin_family = hent->h_addrtype;
 724                         sa.sin_port = htons(0);
 725                         memcpy(&sa.sin_addr, *ap, hent->h_length);
 726
 727                         inet_ntop(hent->h_addrtype, &sa.sin_addr,
 728                                   addrbuf, sizeof(addrbuf));
 729
 730                         sanitize_client(&hi->canon_hostname, hent->h_name);
 731                         strbuf_addstr(&hi->ip_address, addrbuf);
 732                 }
 733 #endif
 734                 hi->hostname_lookup_done = 1;
 735         }
 736 }
 737
 738 static void hostinfo_clear(struct hostinfo *hi)
 739 {
 740         strbuf_release(&hi->hostname);
 741         strbuf_release(&hi->canon_hostname);
 742         strbuf_release(&hi->ip_address);
 743         strbuf_release(&hi->tcp_port);
 744 }
 745
 746 static void set_keep_alive(int sockfd)
 747 {
 748         int ka = 1;
 749
 750         if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0) {
 751                 if (errno != ENOTSOCK)
 752                         logerror("unable to set SO_KEEPALIVE on socket: %s",
 753                                 strerror(errno));
 754         }
 755 }
 756
 757 static int execute(void)
 758 {
 759         char *line = packet_buffer;
 760         int pktlen, len, i;
 761         char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
 762         struct hostinfo hi = HOSTINFO_INIT;
 763         struct strvec env = STRVEC_INIT;
 764
 765         if (addr)
 766                 loginfo("Connection from %s:%s", addr, port);
 767
 768         set_keep_alive(0);
 769         alarm(init_timeout ? init_timeout : timeout);
 770         pktlen = packet_read(0, packet_buffer, sizeof(packet_buffer), 0);
 771         alarm(0);
 772
 773         len = strlen(line);
 774         if (len && line[len-1] == '\n')
 775                 line[len-1] = 0;
 776
 777         /* parse additional args hidden behind a NUL byte */
 778         if (len != pktlen)
 779                 parse_extra_args(&hi, &env, line + len + 1, pktlen - len - 1);
 780
 781         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 782                 struct daemon_service *s = &(daemon_service[i]);
 783                 const char *arg;
 784
 785                 if (skip_prefix(line, "git-", &arg) &&
 786                     skip_prefix(arg, s->name, &arg) &&
 787                     *arg++ == ' ') {
 788                         /*
 789                          * Note: The directory here is probably context sensitive,
 790                          * and might depend on the actual service being performed.
 791                          */
 792                         int rc = run_service(arg, s, &hi, &env);
 793                         hostinfo_clear(&hi);
 794                         strvec_clear(&env);
 795                         return rc;
 796                 }
 797         }
 798
 799         hostinfo_clear(&hi);
 800         strvec_clear(&env);
 801         logerror("Protocol error: '%s'", line);
 802         return -1;
 803 }
 804
 805 static int addrcmp(const struct sockaddr_storage *s1,
 806     const struct sockaddr_storage *s2)
 807 {
 808         const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 809         const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 810
 811         if (sa1->sa_family != sa2->sa_family)
 812                 return sa1->sa_family - sa2->sa_family;
 813         if (sa1->sa_family == AF_INET)
 814                 return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 815                     &((struct sockaddr_in *)s2)->sin_addr,
 816                     sizeof(struct in_addr));
 817 #ifndef NO_IPV6
 818         if (sa1->sa_family == AF_INET6)
 819                 return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 820                     &((struct sockaddr_in6 *)s2)->sin6_addr,
 821                     sizeof(struct in6_addr));
 822 #endif
 823         return 0;
 824 }
 825
 826 static int max_connections = 32;
 827
 828 static unsigned int live_children;
 829
 830 static struct child {
 831         struct child *next;
 832         struct child_process cld;
 833         struct sockaddr_storage address;
 834 } *firstborn;
 835
 836 static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
 837 {
 838         struct child *newborn, **cradle;
 839
 840         CALLOC_ARRAY(newborn, 1);
 841         live_children++;
 842         memcpy(&newborn->cld, cld, sizeof(*cld));
 843         memcpy(&newborn->address, addr, addrlen);
 844         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 845                 if (!addrcmp(&(*cradle)->address, &newborn->address))
 846                         break;
 847         newborn->next = *cradle;
 848         *cradle = newborn;
 849 }
 850
 851 /*
 852  * This gets called if the number of connections grows
 853  * past "max_connections".
 854  *
 855  * We kill the newest connection from a duplicate IP.
 856  */
 857 static void kill_some_child(void)
 858 {
 859         const struct child *blanket, *next;
 860
 861         if (!(blanket = firstborn))
 862                 return;
 863
 864         for (; (next = blanket->next); blanket = next)
 865                 if (!addrcmp(&blanket->address, &next->address)) {
 866                         kill(blanket->cld.pid, SIGTERM);
 867                         break;
 868                 }
 869 }
 870
 871 static void check_dead_children(void)
 872 {
 873         int status;
 874         pid_t pid;
 875
 876         struct child **cradle, *blanket;
 877         for (cradle = &firstborn; (blanket = *cradle);)
 878                 if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
 879                         const char *dead = "";
 880                         if (status)
 881                                 dead = " (with error)";
 882                         loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 883
 884                         /* remove the child */
 885                         *cradle = blanket->next;
 886                         live_children--;
 887                         child_process_clear(&blanket->cld);
 888                         free(blanket);
 889                 } else
 890                         cradle = &blanket->next;
 891 }
 892
 893 static struct strvec cld_argv = STRVEC_INIT;
 894 static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 895 {
 896         struct child_process cld = CHILD_PROCESS_INIT;
 897
 898         if (max_connections && live_children >= max_connections) {
 899                 kill_some_child();
 900                 sleep(1);  /* give it some time to die */
 901                 check_dead_children();
 902                 if (live_children >= max_connections) {
 903                         close(incoming);
 904                         logerror("Too many children, dropping connection");
 905                         return;
 906                 }
 907         }
 908
 909         if (addr->sa_family == AF_INET) {
 910                 char buf[128] = "";
 911                 struct sockaddr_in *sin_addr = (void *) addr;
 912                 inet_ntop(addr->sa_family, &sin_addr->sin_addr, buf, sizeof(buf));
 913                 strvec_pushf(&cld.env, "REMOTE_ADDR=%s", buf);
 914                 strvec_pushf(&cld.env, "REMOTE_PORT=%d",
 915                              ntohs(sin_addr->sin_port));
 916 #ifndef NO_IPV6
 917         } else if (addr->sa_family == AF_INET6) {
 918                 char buf[128] = "";
 919                 struct sockaddr_in6 *sin6_addr = (void *) addr;
 920                 inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(buf));
 921                 strvec_pushf(&cld.env, "REMOTE_ADDR=[%s]", buf);
 922                 strvec_pushf(&cld.env, "REMOTE_PORT=%d",
 923                              ntohs(sin6_addr->sin6_port));
 924 #endif
 925         }
 926
 927         strvec_pushv(&cld.args, cld_argv.v);
 928         cld.in = incoming;
 929         cld.out = dup(incoming);
 930
 931         if (start_command(&cld))
 932                 logerror("unable to fork");
 933         else
 934                 add_child(&cld, addr, addrlen);
 935 }
 936
 937 static void child_handler(int signo UNUSED)
 938 {
 939         /*
 940          * Otherwise empty handler because systemcalls will get interrupted
 941          * upon signal receipt
 942          * SysV needs the handler to be rearmed
 943          */
 944         signal(SIGCHLD, child_handler);
 945 }
 946
 947 static int set_reuse_addr(int sockfd)
 948 {
 949         int on = 1;
 950
 951         if (!reuseaddr)
 952                 return 0;
 953         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 954                           &on, sizeof(on));
 955 }
 956
 957 struct socketlist {
 958         int *list;
 959         size_t nr;
 960         size_t alloc;
 961 };
 962
 963 static const char *ip2str(int family, struct sockaddr *sin, socklen_t len)
 964 {
 965 #ifdef NO_IPV6
 966         static char ip[INET_ADDRSTRLEN];
 967 #else
 968         static char ip[INET6_ADDRSTRLEN];
 969 #endif
 970
 971         switch (family) {
 972 #ifndef NO_IPV6
 973         case AF_INET6:
 974                 inet_ntop(family, &((struct sockaddr_in6*)sin)->sin6_addr, ip, len);
 975                 break;
 976 #endif
 977         case AF_INET:
 978                 inet_ntop(family, &((struct sockaddr_in*)sin)->sin_addr, ip, len);
 979                 break;
 980         default:
 981                 xsnprintf(ip, sizeof(ip), "<unknown>");
 982         }
 983         return ip;
 984 }
 985
 986 #ifndef NO_IPV6
 987
 988 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 989 {
 990         int socknum = 0;
 991         char pbuf[NI_MAXSERV];
 992         struct addrinfo hints, *ai0, *ai;
 993         int gai;
 994         long flags;
 995
 996         xsnprintf(pbuf, sizeof(pbuf), "%d", listen_port);
 997         memset(&hints, 0, sizeof(hints));
 998         hints.ai_family = AF_UNSPEC;
 999         hints.ai_socktype = SOCK_STREAM;
1000         hints.ai_protocol = IPPROTO_TCP;
1001         hints.ai_flags = AI_PASSIVE;
1002
1003         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
1004         if (gai) {
1005                 logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
1006                 return 0;
1007         }
1008
1009         for (ai = ai0; ai; ai = ai->ai_next) {
1010                 int sockfd;
1011
1012                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
1013                 if (sockfd < 0)
1014                         continue;
1015                 if (sockfd >= FD_SETSIZE) {
1016                         logerror("Socket descriptor too large");
1017                         close(sockfd);
1018                         continue;
1019                 }
1020
1021 #ifdef IPV6_V6ONLY
1022                 if (ai->ai_family == AF_INET6) {
1023                         int on = 1;
1024                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
1025                                    &on, sizeof(on));
1026                         /* Note: error is not fatal */
1027                 }
1028 #endif
1029
1030                 if (set_reuse_addr(sockfd)) {
1031                         logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
1032                         close(sockfd);
1033                         continue;
1034                 }
1035
1036                 set_keep_alive(sockfd);
1037
1038                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
1039                         logerror("Could not bind to %s: %s",
1040                                  ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
1041                                  strerror(errno));
1042                         close(sockfd);
1043                         continue;       /* not fatal */
1044                 }
1045                 if (listen(sockfd, 5) < 0) {
1046                         logerror("Could not listen to %s: %s",
1047                                  ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
1048                                  strerror(errno));
1049                         close(sockfd);
1050                         continue;       /* not fatal */
1051                 }
1052
1053                 flags = fcntl(sockfd, F_GETFD, 0);
1054                 if (flags >= 0)
1055                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
1056
1057                 ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
1058                 socklist->list[socklist->nr++] = sockfd;
1059                 socknum++;
1060         }
1061
1062         freeaddrinfo(ai0);
1063
1064         return socknum;
1065 }
1066
1067 #else /* NO_IPV6 */
1068
1069 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
1070 {
1071         struct sockaddr_in sin;
1072         int sockfd;
1073         long flags;
1074
1075         memset(&sin, 0, sizeof sin);
1076         sin.sin_family = AF_INET;
1077         sin.sin_port = htons(listen_port);
1078
1079         if (listen_addr) {
1080                 /* Well, host better be an IP address here. */
1081                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
1082                         return 0;
1083         } else {
1084                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
1085         }
1086
1087         sockfd = socket(AF_INET, SOCK_STREAM, 0);
1088         if (sockfd < 0)
1089                 return 0;
1090
1091         if (set_reuse_addr(sockfd)) {
1092                 logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
1093                 close(sockfd);
1094                 return 0;
1095         }
1096
1097         set_keep_alive(sockfd);
1098
1099         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
1100                 logerror("Could not bind to %s: %s",
1101                          ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
1102                          strerror(errno));
1103                 close(sockfd);
1104                 return 0;
1105         }
1106
1107         if (listen(sockfd, 5) < 0) {
1108                 logerror("Could not listen to %s: %s",
1109                          ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
1110                          strerror(errno));
1111                 close(sockfd);
1112                 return 0;
1113         }
1114
1115         flags = fcntl(sockfd, F_GETFD, 0);
1116         if (flags >= 0)
1117                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
1118
1119         ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
1120         socklist->list[socklist->nr++] = sockfd;
1121         return 1;
1122 }
1123
1124 #endif
1125
1126 static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
1127 {
1128         if (!listen_addr->nr)
1129                 setup_named_sock(NULL, listen_port, socklist);
1130         else {
1131                 int i, socknum;
1132                 for (i = 0; i < listen_addr->nr; i++) {
1133                         socknum = setup_named_sock(listen_addr->items[i].string,
1134                                                    listen_port, socklist);
1135
1136                         if (socknum == 0)
1137                                 logerror("unable to allocate any listen sockets for host %s on port %u",
1138                                          listen_addr->items[i].string, listen_port);
1139                 }
1140         }
1141 }
1142
1143 static int service_loop(struct socketlist *socklist)
1144 {
1145         struct pollfd *pfd;
1146         int i;
1147
1148         CALLOC_ARRAY(pfd, socklist->nr);
1149
1150         for (i = 0; i < socklist->nr; i++) {
1151                 pfd[i].fd = socklist->list[i];
1152                 pfd[i].events = POLLIN;
1153         }
1154
1155         signal(SIGCHLD, child_handler);
1156
1157         for (;;) {
1158                 int i;
1159
1160                 check_dead_children();
1161
1162                 if (poll(pfd, socklist->nr, -1) < 0) {
1163                         if (errno != EINTR) {
1164                                 logerror("Poll failed, resuming: %s",
1165                                       strerror(errno));
1166                                 sleep(1);
1167                         }
1168                         continue;
1169                 }
1170
1171                 for (i = 0; i < socklist->nr; i++) {
1172                         if (pfd[i].revents & POLLIN) {
1173                                 union {
1174                                         struct sockaddr sa;
1175                                         struct sockaddr_in sai;
1176 #ifndef NO_IPV6
1177                                         struct sockaddr_in6 sai6;
1178 #endif
1179                                 } ss;
1180                                 socklen_t sslen = sizeof(ss);
1181                                 int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
1182                                 if (incoming < 0) {
1183                                         switch (errno) {
1184                                         case EAGAIN:
1185                                         case EINTR:
1186                                         case ECONNABORTED:
1187                                                 continue;
1188                                         default:
1189                                                 die_errno("accept returned");
1190                                         }
1191                                 }
1192                                 handle(incoming, &ss.sa, sslen);
1193                         }
1194                 }
1195         }
1196 }
1197
1198 #ifdef NO_POSIX_GOODIES
1199
1200 struct credentials;
1201
1202 static void drop_privileges(struct credentials *cred)
1203 {
1204         /* nothing */
1205 }
1206
1207 static struct credentials *prepare_credentials(const char *user_name,
1208     const char *group_name)
1209 {
1210         die("--user not supported on this platform");
1211 }
1212
1213 #else
1214
1215 struct credentials {
1216         struct passwd *pass;
1217         gid_t gid;
1218 };
1219
1220 static void drop_privileges(struct credentials *cred)
1221 {
1222         if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
1223             setgid (cred->gid) || setuid(cred->pass->pw_uid)))
1224                 die("cannot drop privileges");
1225 }
1226
1227 static struct credentials *prepare_credentials(const char *user_name,
1228     const char *group_name)
1229 {
1230         static struct credentials c;
1231
1232         c.pass = getpwnam(user_name);
1233         if (!c.pass)
1234                 die("user not found - %s", user_name);
1235
1236         if (!group_name)
1237                 c.gid = c.pass->pw_gid;
1238         else {
1239                 struct group *group = getgrnam(group_name);
1240                 if (!group)
1241                         die("group not found - %s", group_name);
1242
1243                 c.gid = group->gr_gid;
1244         }
1245
1246         return &c;
1247 }
1248 #endif
1249
1250 static int serve(struct string_list *listen_addr, int listen_port,
1251     struct credentials *cred)
1252 {
1253         struct socketlist socklist = { NULL, 0, 0 };
1254
1255         socksetup(listen_addr, listen_port, &socklist);
1256         if (socklist.nr == 0)
1257                 die("unable to allocate any listen sockets on port %u",
1258                     listen_port);
1259
1260         drop_privileges(cred);
1261
1262         loginfo("Ready to rumble");
1263
1264         return service_loop(&socklist);
1265 }
1266
1267 int cmd_main(int argc, const char **argv)
1268 {
1269         int listen_port = 0;
1270         struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1271         int serve_mode = 0, inetd_mode = 0;
1272         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1273         int detach = 0;
1274         struct credentials *cred = NULL;
1275         int i;
1276
1277         for (i = 1; i < argc; i++) {
1278                 const char *arg = argv[i];
1279                 const char *v;
1280
1281                 if (skip_prefix(arg, "--listen=", &v)) {
1282                         string_list_append(&listen_addr, xstrdup_tolower(v));
1283                         continue;
1284                 }
1285                 if (skip_prefix(arg, "--port=", &v)) {
1286                         char *end;
1287                         unsigned long n;
1288                         n = strtoul(v, &end, 0);
1289                         if (*v && !*end) {
1290                                 listen_port = n;
1291                                 continue;
1292                         }
1293                 }
1294                 if (!strcmp(arg, "--serve")) {
1295                         serve_mode = 1;
1296                         continue;
1297                 }
1298                 if (!strcmp(arg, "--inetd")) {
1299                         inetd_mode = 1;
1300                         continue;
1301                 }
1302                 if (!strcmp(arg, "--verbose")) {
1303                         verbose = 1;
1304                         continue;
1305                 }
1306                 if (!strcmp(arg, "--syslog")) {
1307                         log_destination = LOG_DESTINATION_SYSLOG;
1308                         continue;
1309                 }
1310                 if (skip_prefix(arg, "--log-destination=", &v)) {
1311                         if (!strcmp(v, "syslog")) {
1312                                 log_destination = LOG_DESTINATION_SYSLOG;
1313                                 continue;
1314                         } else if (!strcmp(v, "stderr")) {
1315                                 log_destination = LOG_DESTINATION_STDERR;
1316                                 continue;
1317                         } else if (!strcmp(v, "none")) {
1318                                 log_destination = LOG_DESTINATION_NONE;
1319                                 continue;
1320                         } else
1321                                 die("unknown log destination '%s'", v);
1322                 }
1323                 if (!strcmp(arg, "--export-all")) {
1324                         export_all_trees = 1;
1325                         continue;
1326                 }
1327                 if (skip_prefix(arg, "--access-hook=", &v)) {
1328                         access_hook = v;
1329                         continue;
1330                 }
1331                 if (skip_prefix(arg, "--timeout=", &v)) {
1332                         timeout = atoi(v);
1333                         continue;
1334                 }
1335                 if (skip_prefix(arg, "--init-timeout=", &v)) {
1336                         init_timeout = atoi(v);
1337                         continue;
1338                 }
1339                 if (skip_prefix(arg, "--max-connections=", &v)) {
1340                         max_connections = atoi(v);
1341                         if (max_connections < 0)
1342                                 max_connections = 0;            /* unlimited */
1343                         continue;
1344                 }
1345                 if (!strcmp(arg, "--strict-paths")) {
1346                         strict_paths = 1;
1347                         continue;
1348                 }
1349                 if (skip_prefix(arg, "--base-path=", &v)) {
1350                         base_path = v;
1351                         continue;
1352                 }
1353                 if (!strcmp(arg, "--base-path-relaxed")) {
1354                         base_path_relaxed = 1;
1355                         continue;
1356                 }
1357                 if (skip_prefix(arg, "--interpolated-path=", &v)) {
1358                         interpolated_path = v;
1359                         continue;
1360                 }
1361                 if (!strcmp(arg, "--reuseaddr")) {
1362                         reuseaddr = 1;
1363                         continue;
1364                 }
1365                 if (!strcmp(arg, "--user-path")) {
1366                         user_path = "";
1367                         continue;
1368                 }
1369                 if (skip_prefix(arg, "--user-path=", &v)) {
1370                         user_path = v;
1371                         continue;
1372                 }
1373                 if (skip_prefix(arg, "--pid-file=", &v)) {
1374                         pid_file = v;
1375                         continue;
1376                 }
1377                 if (!strcmp(arg, "--detach")) {
1378                         detach = 1;
1379                         continue;
1380                 }
1381                 if (skip_prefix(arg, "--user=", &v)) {
1382                         user_name = v;
1383                         continue;
1384                 }
1385                 if (skip_prefix(arg, "--group=", &v)) {
1386                         group_name = v;
1387                         continue;
1388                 }
1389                 if (skip_prefix(arg, "--enable=", &v)) {
1390                         enable_service(v, 1);
1391                         continue;
1392                 }
1393                 if (skip_prefix(arg, "--disable=", &v)) {
1394                         enable_service(v, 0);
1395                         continue;
1396                 }
1397                 if (skip_prefix(arg, "--allow-override=", &v)) {
1398                         make_service_overridable(v, 1);
1399                         continue;
1400                 }
1401                 if (skip_prefix(arg, "--forbid-override=", &v)) {
1402                         make_service_overridable(v, 0);
1403                         continue;
1404                 }
1405                 if (!strcmp(arg, "--informative-errors")) {
1406                         informative_errors = 1;
1407                         continue;
1408                 }
1409                 if (!strcmp(arg, "--no-informative-errors")) {
1410                         informative_errors = 0;
1411                         continue;
1412                 }
1413                 if (!strcmp(arg, "--")) {
1414                         ok_paths = &argv[i+1];
1415                         break;
1416                 } else if (arg[0] != '-') {
1417                         ok_paths = &argv[i];
1418                         break;
1419                 }
1420
1421                 usage(daemon_usage);
1422         }
1423
1424         if (log_destination == LOG_DESTINATION_UNSET) {
1425                 if (inetd_mode || detach)
1426                         log_destination = LOG_DESTINATION_SYSLOG;
1427                 else
1428                         log_destination = LOG_DESTINATION_STDERR;
1429         }
1430
1431         if (log_destination == LOG_DESTINATION_SYSLOG) {
1432                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1433                 set_die_routine(daemon_die);
1434         } else
1435                 /* avoid splitting a message in the middle */
1436                 setvbuf(stderr, NULL, _IOFBF, 4096);
1437
1438         if (inetd_mode && (detach || group_name || user_name))
1439                 die("--detach, --user and --group are incompatible with --inetd");
1440
1441         if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1442                 die("--listen= and --port= are incompatible with --inetd");
1443         else if (listen_port == 0)
1444                 listen_port = DEFAULT_GIT_PORT;
1445
1446         if (group_name && !user_name)
1447                 die("--group supplied without --user");
1448
1449         if (user_name)
1450                 cred = prepare_credentials(user_name, group_name);
1451
1452         if (strict_paths && (!ok_paths || !*ok_paths))
1453                 die("option --strict-paths requires '<directory>' arguments");
1454
1455         if (base_path && !is_directory(base_path))
1456                 die("base-path '%s' does not exist or is not a directory",
1457                     base_path);
1458
1459         if (log_destination != LOG_DESTINATION_STDERR) {
1460                 if (!freopen("/dev/null", "w", stderr))
1461                         die_errno("failed to redirect stderr to /dev/null");
1462         }
1463
1464         if (inetd_mode || serve_mode)
1465                 return execute();
1466
1467         if (detach) {
1468                 if (daemonize())
1469                         die("--detach not supported on this platform");
1470         }
1471
1472         if (pid_file)
1473                 write_file(pid_file, "%"PRIuMAX, (uintmax_t) getpid());
1474
1475         /* prepare argv for serving-processes */
1476         strvec_push(&cld_argv, argv[0]); /* git-daemon */
1477         strvec_push(&cld_argv, "--serve");
1478         for (i = 1; i < argc; ++i)
1479                 strvec_push(&cld_argv, argv[i]);
1480
1481         return serve(&listen_addr, listen_port, cred);
1482 }