daemon.c

   1 #include "cache.h"
   2 #include "pkt-line.h"
   3 #include "exec_cmd.h"
   4 #include "run-command.h"
   5 #include "strbuf.h"
   6
   7 #include <syslog.h>
   8
   9 #ifndef HOST_NAME_MAX
  10 #define HOST_NAME_MAX 256
  11 #endif
  12
  13 #ifndef NI_MAXSERV
  14 #define NI_MAXSERV 32
  15 #endif
  16
  17 static int log_syslog;
  18 static int verbose;
  19 static int reuseaddr;
  20
  21 static const char daemon_usage[] =
  22 "git daemon [--verbose] [--syslog] [--export-all]\n"
  23 "           [--timeout=n] [--init-timeout=n] [--max-connections=n]\n"
  24 "           [--strict-paths] [--base-path=path] [--base-path-relaxed]\n"
  25 "           [--user-path | --user-path=path]\n"
  26 "           [--interpolated-path=path]\n"
  27 "           [--reuseaddr] [--detach] [--pid-file=file]\n"
  28 "           [--[enable|disable|allow-override|forbid-override]=service]\n"
  29 "           [--inetd | [--listen=host_or_ipaddr] [--port=n]\n"
  30 "                      [--user=user [--group=group]]\n"
  31 "           [directory...]";
  32
  33 /* List of acceptable pathname prefixes */
  34 static char **ok_paths;
  35 static int strict_paths;
  36
  37 /* If this is set, git-daemon-export-ok is not required */
  38 static int export_all_trees;
  39
  40 /* Take all paths relative to this one if non-NULL */
  41 static char *base_path;
  42 static char *interpolated_path;
  43 static int base_path_relaxed;
  44
  45 /* Flag indicating client sent extra args. */
  46 static int saw_extended_args;
  47
  48 /* If defined, ~user notation is allowed and the string is inserted
  49  * after ~user/.  E.g. a request to git://host/~alice/frotz would
  50  * go to /home/alice/pub_git/frotz with --user-path=pub_git.
  51  */
  52 static const char *user_path;
  53
  54 /* Timeout, and initial timeout */
  55 static unsigned int timeout;
  56 static unsigned int init_timeout;
  57
  58 static char *hostname;
  59 static char *canon_hostname;
  60 static char *ip_address;
  61 static char *tcp_port;
  62
  63 static void logreport(int priority, const char *err, va_list params)
  64 {
  65         if (log_syslog) {
  66                 char buf[1024];
  67                 vsnprintf(buf, sizeof(buf), err, params);
  68                 syslog(priority, "%s", buf);
  69         } else {
  70                 /*
  71                  * Since stderr is set to linebuffered mode, the
  72                  * logging of different processes will not overlap
  73                  */
  74                 fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
  75                 vfprintf(stderr, err, params);
  76                 fputc('\n', stderr);
  77         }
  78 }
  79
  80 __attribute__((format (printf, 1, 2)))
  81 static void logerror(const char *err, ...)
  82 {
  83         va_list params;
  84         va_start(params, err);
  85         logreport(LOG_ERR, err, params);
  86         va_end(params);
  87 }
  88
  89 __attribute__((format (printf, 1, 2)))
  90 static void loginfo(const char *err, ...)
  91 {
  92         va_list params;
  93         if (!verbose)
  94                 return;
  95         va_start(params, err);
  96         logreport(LOG_INFO, err, params);
  97         va_end(params);
  98 }
  99
 100 static void NORETURN daemon_die(const char *err, va_list params)
 101 {
 102         logreport(LOG_ERR, err, params);
 103         exit(1);
 104 }
 105
 106 static char *path_ok(char *directory)
 107 {
 108         static char rpath[PATH_MAX];
 109         static char interp_path[PATH_MAX];
 110         char *path;
 111         char *dir;
 112
 113         dir = directory;
 114
 115         if (daemon_avoid_alias(dir)) {
 116                 logerror("'%s': aliased", dir);
 117                 return NULL;
 118         }
 119
 120         if (*dir == '~') {
 121                 if (!user_path) {
 122                         logerror("'%s': User-path not allowed", dir);
 123                         return NULL;
 124                 }
 125                 if (*user_path) {
 126                         /* Got either "~alice" or "~alice/foo";
 127                          * rewrite them to "~alice/%s" or
 128                          * "~alice/%s/foo".
 129                          */
 130                         int namlen, restlen = strlen(dir);
 131                         char *slash = strchr(dir, '/');
 132                         if (!slash)
 133                                 slash = dir + restlen;
 134                         namlen = slash - dir;
 135                         restlen -= namlen;
 136                         loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
 137                         snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
 138                                  namlen, dir, user_path, restlen, slash);
 139                         dir = rpath;
 140                 }
 141         }
 142         else if (interpolated_path && saw_extended_args) {
 143                 struct strbuf expanded_path = STRBUF_INIT;
 144                 struct strbuf_expand_dict_entry dict[] = {
 145                         { "H", hostname },
 146                         { "CH", canon_hostname },
 147                         { "IP", ip_address },
 148                         { "P", tcp_port },
 149                         { "D", directory },
 150                         { "%", "%" },
 151                         { NULL }
 152                 };
 153
 154                 if (*dir != '/') {
 155                         /* Allow only absolute */
 156                         logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 157                         return NULL;
 158                 }
 159
 160                 strbuf_expand(&expanded_path, interpolated_path,
 161                                 strbuf_expand_dict_cb, &dict);
 162                 strlcpy(interp_path, expanded_path.buf, PATH_MAX);
 163                 strbuf_release(&expanded_path);
 164                 loginfo("Interpolated dir '%s'", interp_path);
 165
 166                 dir = interp_path;
 167         }
 168         else if (base_path) {
 169                 if (*dir != '/') {
 170                         /* Allow only absolute */
 171                         logerror("'%s': Non-absolute path denied (base-path active)", dir);
 172                         return NULL;
 173                 }
 174                 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
 175                 dir = rpath;
 176         }
 177
 178         path = enter_repo(dir, strict_paths);
 179         if (!path && base_path && base_path_relaxed) {
 180                 /*
 181                  * if we fail and base_path_relaxed is enabled, try without
 182                  * prefixing the base path
 183                  */
 184                 dir = directory;
 185                 path = enter_repo(dir, strict_paths);
 186         }
 187
 188         if (!path) {
 189                 logerror("'%s' does not appear to be a git repository", dir);
 190                 return NULL;
 191         }
 192
 193         if ( ok_paths && *ok_paths ) {
 194                 char **pp;
 195                 int pathlen = strlen(path);
 196
 197                 /* The validation is done on the paths after enter_repo
 198                  * appends optional {.git,.git/.git} and friends, but
 199                  * it does not use getcwd().  So if your /pub is
 200                  * a symlink to /mnt/pub, you can whitelist /pub and
 201                  * do not have to say /mnt/pub.
 202                  * Do not say /pub/.
 203                  */
 204                 for ( pp = ok_paths ; *pp ; pp++ ) {
 205                         int len = strlen(*pp);
 206                         if (len <= pathlen &&
 207                             !memcmp(*pp, path, len) &&
 208                             (path[len] == '\0' ||
 209                              (!strict_paths && path[len] == '/')))
 210                                 return path;
 211                 }
 212         }
 213         else {
 214                 /* be backwards compatible */
 215                 if (!strict_paths)
 216                         return path;
 217         }
 218
 219         logerror("'%s': not in whitelist", path);
 220         return NULL;            /* Fallthrough. Deny by default */
 221 }
 222
 223 typedef int (*daemon_service_fn)(void);
 224 struct daemon_service {
 225         const char *name;
 226         const char *config_name;
 227         daemon_service_fn fn;
 228         int enabled;
 229         int overridable;
 230 };
 231
 232 static struct daemon_service *service_looking_at;
 233 static int service_enabled;
 234
 235 static int git_daemon_config(const char *var, const char *value, void *cb)
 236 {
 237         if (!prefixcmp(var, "daemon.") &&
 238             !strcmp(var + 7, service_looking_at->config_name)) {
 239                 service_enabled = git_config_bool(var, value);
 240                 return 0;
 241         }
 242
 243         /* we are not interested in parsing any other configuration here */
 244         return 0;
 245 }
 246
 247 static int run_service(char *dir, struct daemon_service *service)
 248 {
 249         const char *path;
 250         int enabled = service->enabled;
 251
 252         loginfo("Request %s for '%s'", service->name, dir);
 253
 254         if (!enabled && !service->overridable) {
 255                 logerror("'%s': service not enabled.", service->name);
 256                 errno = EACCES;
 257                 return -1;
 258         }
 259
 260         if (!(path = path_ok(dir)))
 261                 return -1;
 262
 263         /*
 264          * Security on the cheap.
 265          *
 266          * We want a readable HEAD, usable "objects" directory, and
 267          * a "git-daemon-export-ok" flag that says that the other side
 268          * is ok with us doing this.
 269          *
 270          * path_ok() uses enter_repo() and does whitelist checking.
 271          * We only need to make sure the repository is exported.
 272          */
 273
 274         if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 275                 logerror("'%s': repository not exported.", path);
 276                 errno = EACCES;
 277                 return -1;
 278         }
 279
 280         if (service->overridable) {
 281                 service_looking_at = service;
 282                 service_enabled = -1;
 283                 git_config(git_daemon_config, NULL);
 284                 if (0 <= service_enabled)
 285                         enabled = service_enabled;
 286         }
 287         if (!enabled) {
 288                 logerror("'%s': service not enabled for '%s'",
 289                          service->name, path);
 290                 errno = EACCES;
 291                 return -1;
 292         }
 293
 294         /*
 295          * We'll ignore SIGTERM from now on, we have a
 296          * good client.
 297          */
 298         signal(SIGTERM, SIG_IGN);
 299
 300         return service->fn();
 301 }
 302
 303 static void copy_to_log(int fd)
 304 {
 305         struct strbuf line = STRBUF_INIT;
 306         FILE *fp;
 307
 308         fp = fdopen(fd, "r");
 309         if (fp == NULL) {
 310                 logerror("fdopen of error channel failed");
 311                 close(fd);
 312                 return;
 313         }
 314
 315         while (strbuf_getline(&line, fp, '\n') != EOF) {
 316                 logerror("%s", line.buf);
 317                 strbuf_setlen(&line, 0);
 318         }
 319
 320         strbuf_release(&line);
 321         fclose(fp);
 322 }
 323
 324 static int run_service_command(const char **argv)
 325 {
 326         struct child_process cld;
 327
 328         memset(&cld, 0, sizeof(cld));
 329         cld.argv = argv;
 330         cld.git_cmd = 1;
 331         cld.err = -1;
 332         if (start_command(&cld))
 333                 return -1;
 334
 335         close(0);
 336         close(1);
 337
 338         copy_to_log(cld.err);
 339
 340         return finish_command(&cld);
 341 }
 342
 343 static int upload_pack(void)
 344 {
 345         /* Timeout as string */
 346         char timeout_buf[64];
 347         const char *argv[] = { "upload-pack", "--strict", timeout_buf, ".", NULL };
 348
 349         snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 350         return run_service_command(argv);
 351 }
 352
 353 static int upload_archive(void)
 354 {
 355         static const char *argv[] = { "upload-archive", ".", NULL };
 356         return run_service_command(argv);
 357 }
 358
 359 static int receive_pack(void)
 360 {
 361         static const char *argv[] = { "receive-pack", ".", NULL };
 362         return run_service_command(argv);
 363 }
 364
 365 static struct daemon_service daemon_service[] = {
 366         { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 367         { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 368         { "receive-pack", "receivepack", receive_pack, 0, 1 },
 369 };
 370
 371 static void enable_service(const char *name, int ena)
 372 {
 373         int i;
 374         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 375                 if (!strcmp(daemon_service[i].name, name)) {
 376                         daemon_service[i].enabled = ena;
 377                         return;
 378                 }
 379         }
 380         die("No such service %s", name);
 381 }
 382
 383 static void make_service_overridable(const char *name, int ena)
 384 {
 385         int i;
 386         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 387                 if (!strcmp(daemon_service[i].name, name)) {
 388                         daemon_service[i].overridable = ena;
 389                         return;
 390                 }
 391         }
 392         die("No such service %s", name);
 393 }
 394
 395 static char *xstrdup_tolower(const char *str)
 396 {
 397         char *p, *dup = xstrdup(str);
 398         for (p = dup; *p; p++)
 399                 *p = tolower(*p);
 400         return dup;
 401 }
 402
 403 /*
 404  * Read the host as supplied by the client connection.
 405  */
 406 static void parse_host_arg(char *extra_args, int buflen)
 407 {
 408         char *val;
 409         int vallen;
 410         char *end = extra_args + buflen;
 411
 412         if (extra_args < end && *extra_args) {
 413                 saw_extended_args = 1;
 414                 if (strncasecmp("host=", extra_args, 5) == 0) {
 415                         val = extra_args + 5;
 416                         vallen = strlen(val) + 1;
 417                         if (*val) {
 418                                 /* Split <host>:<port> at colon. */
 419                                 char *host = val;
 420                                 char *port = strrchr(host, ':');
 421                                 if (port) {
 422                                         *port = 0;
 423                                         port++;
 424                                         free(tcp_port);
 425                                         tcp_port = xstrdup(port);
 426                                 }
 427                                 free(hostname);
 428                                 hostname = xstrdup_tolower(host);
 429                         }
 430
 431                         /* On to the next one */
 432                         extra_args = val + vallen;
 433                 }
 434                 if (extra_args < end && *extra_args)
 435                         die("Invalid request");
 436         }
 437
 438         /*
 439          * Locate canonical hostname and its IP address.
 440          */
 441         if (hostname) {
 442 #ifndef NO_IPV6
 443                 struct addrinfo hints;
 444                 struct addrinfo *ai;
 445                 int gai;
 446                 static char addrbuf[HOST_NAME_MAX + 1];
 447
 448                 memset(&hints, 0, sizeof(hints));
 449                 hints.ai_flags = AI_CANONNAME;
 450
 451                 gai = getaddrinfo(hostname, NULL, &hints, &ai);
 452                 if (!gai) {
 453                         struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 454
 455                         inet_ntop(AF_INET, &sin_addr->sin_addr,
 456                                   addrbuf, sizeof(addrbuf));
 457                         free(ip_address);
 458                         ip_address = xstrdup(addrbuf);
 459
 460                         free(canon_hostname);
 461                         canon_hostname = xstrdup(ai->ai_canonname ?
 462                                                  ai->ai_canonname : ip_address);
 463
 464                         freeaddrinfo(ai);
 465                 }
 466 #else
 467                 struct hostent *hent;
 468                 struct sockaddr_in sa;
 469                 char **ap;
 470                 static char addrbuf[HOST_NAME_MAX + 1];
 471
 472                 hent = gethostbyname(hostname);
 473
 474                 ap = hent->h_addr_list;
 475                 memset(&sa, 0, sizeof sa);
 476                 sa.sin_family = hent->h_addrtype;
 477                 sa.sin_port = htons(0);
 478                 memcpy(&sa.sin_addr, *ap, hent->h_length);
 479
 480                 inet_ntop(hent->h_addrtype, &sa.sin_addr,
 481                           addrbuf, sizeof(addrbuf));
 482
 483                 free(canon_hostname);
 484                 canon_hostname = xstrdup(hent->h_name);
 485                 free(ip_address);
 486                 ip_address = xstrdup(addrbuf);
 487 #endif
 488         }
 489 }
 490
 491
 492 static int execute(struct sockaddr *addr)
 493 {
 494         static char line[1000];
 495         int pktlen, len, i;
 496
 497         if (addr) {
 498                 char addrbuf[256] = "";
 499                 int port = -1;
 500
 501                 if (addr->sa_family == AF_INET) {
 502                         struct sockaddr_in *sin_addr = (void *) addr;
 503                         inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
 504                         port = ntohs(sin_addr->sin_port);
 505 #ifndef NO_IPV6
 506                 } else if (addr && addr->sa_family == AF_INET6) {
 507                         struct sockaddr_in6 *sin6_addr = (void *) addr;
 508
 509                         char *buf = addrbuf;
 510                         *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 511                         inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
 512                         strcat(buf, "]");
 513
 514                         port = ntohs(sin6_addr->sin6_port);
 515 #endif
 516                 }
 517                 loginfo("Connection from %s:%d", addrbuf, port);
 518                 setenv("REMOTE_ADDR", addrbuf, 1);
 519         }
 520         else {
 521                 unsetenv("REMOTE_ADDR");
 522         }
 523
 524         alarm(init_timeout ? init_timeout : timeout);
 525         pktlen = packet_read_line(0, line, sizeof(line));
 526         alarm(0);
 527
 528         len = strlen(line);
 529         if (pktlen != len)
 530                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
 531                         (int) pktlen - len,
 532                         (int) pktlen - len, line + len + 1);
 533         if (len && line[len-1] == '\n') {
 534                 line[--len] = 0;
 535                 pktlen--;
 536         }
 537
 538         free(hostname);
 539         free(canon_hostname);
 540         free(ip_address);
 541         free(tcp_port);
 542         hostname = canon_hostname = ip_address = tcp_port = NULL;
 543
 544         if (len != pktlen)
 545                 parse_host_arg(line + len + 1, pktlen - len - 1);
 546
 547         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 548                 struct daemon_service *s = &(daemon_service[i]);
 549                 int namelen = strlen(s->name);
 550                 if (!prefixcmp(line, "git-") &&
 551                     !strncmp(s->name, line + 4, namelen) &&
 552                     line[namelen + 4] == ' ') {
 553                         /*
 554                          * Note: The directory here is probably context sensitive,
 555                          * and might depend on the actual service being performed.
 556                          */
 557                         return run_service(line + namelen + 5, s);
 558                 }
 559         }
 560
 561         logerror("Protocol error: '%s'", line);
 562         return -1;
 563 }
 564
 565 static int max_connections = 32;
 566
 567 static unsigned int live_children;
 568
 569 static struct child {
 570         struct child *next;
 571         pid_t pid;
 572         struct sockaddr_storage address;
 573 } *firstborn;
 574
 575 static void add_child(pid_t pid, struct sockaddr *addr, int addrlen)
 576 {
 577         struct child *newborn, **cradle;
 578
 579         /*
 580          * This must be xcalloc() -- we'll compare the whole sockaddr_storage
 581          * but individual address may be shorter.
 582          */
 583         newborn = xcalloc(1, sizeof(*newborn));
 584         live_children++;
 585         newborn->pid = pid;
 586         memcpy(&newborn->address, addr, addrlen);
 587         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 588                 if (!memcmp(&(*cradle)->address, &newborn->address,
 589                             sizeof(newborn->address)))
 590                         break;
 591         newborn->next = *cradle;
 592         *cradle = newborn;
 593 }
 594
 595 static void remove_child(pid_t pid)
 596 {
 597         struct child **cradle, *blanket;
 598
 599         for (cradle = &firstborn; (blanket = *cradle); cradle = &blanket->next)
 600                 if (blanket->pid == pid) {
 601                         *cradle = blanket->next;
 602                         live_children--;
 603                         free(blanket);
 604                         break;
 605                 }
 606 }
 607
 608 /*
 609  * This gets called if the number of connections grows
 610  * past "max_connections".
 611  *
 612  * We kill the newest connection from a duplicate IP.
 613  */
 614 static void kill_some_child(void)
 615 {
 616         const struct child *blanket, *next;
 617
 618         if (!(blanket = firstborn))
 619                 return;
 620
 621         for (; (next = blanket->next); blanket = next)
 622                 if (!memcmp(&blanket->address, &next->address,
 623                             sizeof(next->address))) {
 624                         kill(blanket->pid, SIGTERM);
 625                         break;
 626                 }
 627 }
 628
 629 static void check_dead_children(void)
 630 {
 631         int status;
 632         pid_t pid;
 633
 634         while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
 635                 const char *dead = "";
 636                 remove_child(pid);
 637                 if (!WIFEXITED(status) || (WEXITSTATUS(status) > 0))
 638                         dead = " (with error)";
 639                 loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 640         }
 641 }
 642
 643 static void handle(int incoming, struct sockaddr *addr, int addrlen)
 644 {
 645         pid_t pid;
 646
 647         if (max_connections && live_children >= max_connections) {
 648                 kill_some_child();
 649                 sleep(1);  /* give it some time to die */
 650                 check_dead_children();
 651                 if (live_children >= max_connections) {
 652                         close(incoming);
 653                         logerror("Too many children, dropping connection");
 654                         return;
 655                 }
 656         }
 657
 658         if ((pid = fork())) {
 659                 close(incoming);
 660                 if (pid < 0) {
 661                         logerror("Couldn't fork %s", strerror(errno));
 662                         return;
 663                 }
 664
 665                 add_child(pid, addr, addrlen);
 666                 return;
 667         }
 668
 669         dup2(incoming, 0);
 670         dup2(incoming, 1);
 671         close(incoming);
 672
 673         exit(execute(addr));
 674 }
 675
 676 static void child_handler(int signo)
 677 {
 678         /*
 679          * Otherwise empty handler because systemcalls will get interrupted
 680          * upon signal receipt
 681          * SysV needs the handler to be rearmed
 682          */
 683         signal(SIGCHLD, child_handler);
 684 }
 685
 686 static int set_reuse_addr(int sockfd)
 687 {
 688         int on = 1;
 689
 690         if (!reuseaddr)
 691                 return 0;
 692         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 693                           &on, sizeof(on));
 694 }
 695
 696 #ifndef NO_IPV6
 697
 698 static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 699 {
 700         int socknum = 0, *socklist = NULL;
 701         int maxfd = -1;
 702         char pbuf[NI_MAXSERV];
 703         struct addrinfo hints, *ai0, *ai;
 704         int gai;
 705         long flags;
 706
 707         sprintf(pbuf, "%d", listen_port);
 708         memset(&hints, 0, sizeof(hints));
 709         hints.ai_family = AF_UNSPEC;
 710         hints.ai_socktype = SOCK_STREAM;
 711         hints.ai_protocol = IPPROTO_TCP;
 712         hints.ai_flags = AI_PASSIVE;
 713
 714         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 715         if (gai)
 716                 die("getaddrinfo() failed: %s", gai_strerror(gai));
 717
 718         for (ai = ai0; ai; ai = ai->ai_next) {
 719                 int sockfd;
 720
 721                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 722                 if (sockfd < 0)
 723                         continue;
 724                 if (sockfd >= FD_SETSIZE) {
 725                         logerror("Socket descriptor too large");
 726                         close(sockfd);
 727                         continue;
 728                 }
 729
 730 #ifdef IPV6_V6ONLY
 731                 if (ai->ai_family == AF_INET6) {
 732                         int on = 1;
 733                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 734                                    &on, sizeof(on));
 735                         /* Note: error is not fatal */
 736                 }
 737 #endif
 738
 739                 if (set_reuse_addr(sockfd)) {
 740                         close(sockfd);
 741                         continue;
 742                 }
 743
 744                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 745                         close(sockfd);
 746                         continue;       /* not fatal */
 747                 }
 748                 if (listen(sockfd, 5) < 0) {
 749                         close(sockfd);
 750                         continue;       /* not fatal */
 751                 }
 752
 753                 flags = fcntl(sockfd, F_GETFD, 0);
 754                 if (flags >= 0)
 755                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 756
 757                 socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
 758                 socklist[socknum++] = sockfd;
 759
 760                 if (maxfd < sockfd)
 761                         maxfd = sockfd;
 762         }
 763
 764         freeaddrinfo(ai0);
 765
 766         *socklist_p = socklist;
 767         return socknum;
 768 }
 769
 770 #else /* NO_IPV6 */
 771
 772 static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 773 {
 774         struct sockaddr_in sin;
 775         int sockfd;
 776         long flags;
 777
 778         memset(&sin, 0, sizeof sin);
 779         sin.sin_family = AF_INET;
 780         sin.sin_port = htons(listen_port);
 781
 782         if (listen_addr) {
 783                 /* Well, host better be an IP address here. */
 784                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 785                         return 0;
 786         } else {
 787                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
 788         }
 789
 790         sockfd = socket(AF_INET, SOCK_STREAM, 0);
 791         if (sockfd < 0)
 792                 return 0;
 793
 794         if (set_reuse_addr(sockfd)) {
 795                 close(sockfd);
 796                 return 0;
 797         }
 798
 799         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 800                 close(sockfd);
 801                 return 0;
 802         }
 803
 804         if (listen(sockfd, 5) < 0) {
 805                 close(sockfd);
 806                 return 0;
 807         }
 808
 809         flags = fcntl(sockfd, F_GETFD, 0);
 810         if (flags >= 0)
 811                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 812
 813         *socklist_p = xmalloc(sizeof(int));
 814         **socklist_p = sockfd;
 815         return 1;
 816 }
 817
 818 #endif
 819
 820 static int service_loop(int socknum, int *socklist)
 821 {
 822         struct pollfd *pfd;
 823         int i;
 824
 825         pfd = xcalloc(socknum, sizeof(struct pollfd));
 826
 827         for (i = 0; i < socknum; i++) {
 828                 pfd[i].fd = socklist[i];
 829                 pfd[i].events = POLLIN;
 830         }
 831
 832         signal(SIGCHLD, child_handler);
 833
 834         for (;;) {
 835                 int i;
 836
 837                 check_dead_children();
 838
 839                 if (poll(pfd, socknum, -1) < 0) {
 840                         if (errno != EINTR) {
 841                                 logerror("Poll failed, resuming: %s",
 842                                       strerror(errno));
 843                                 sleep(1);
 844                         }
 845                         continue;
 846                 }
 847
 848                 for (i = 0; i < socknum; i++) {
 849                         if (pfd[i].revents & POLLIN) {
 850                                 struct sockaddr_storage ss;
 851                                 unsigned int sslen = sizeof(ss);
 852                                 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
 853                                 if (incoming < 0) {
 854                                         switch (errno) {
 855                                         case EAGAIN:
 856                                         case EINTR:
 857                                         case ECONNABORTED:
 858                                                 continue;
 859                                         default:
 860                                                 die_errno("accept returned");
 861                                         }
 862                                 }
 863                                 handle(incoming, (struct sockaddr *)&ss, sslen);
 864                         }
 865                 }
 866         }
 867 }
 868
 869 /* if any standard file descriptor is missing open it to /dev/null */
 870 static void sanitize_stdfds(void)
 871 {
 872         int fd = open("/dev/null", O_RDWR, 0);
 873         while (fd != -1 && fd < 2)
 874                 fd = dup(fd);
 875         if (fd == -1)
 876                 die_errno("open /dev/null or dup failed");
 877         if (fd > 2)
 878                 close(fd);
 879 }
 880
 881 static void daemonize(void)
 882 {
 883         switch (fork()) {
 884                 case 0:
 885                         break;
 886                 case -1:
 887                         die_errno("fork failed");
 888                 default:
 889                         exit(0);
 890         }
 891         if (setsid() == -1)
 892                 die_errno("setsid failed");
 893         close(0);
 894         close(1);
 895         close(2);
 896         sanitize_stdfds();
 897 }
 898
 899 static void store_pid(const char *path)
 900 {
 901         FILE *f = fopen(path, "w");
 902         if (!f)
 903                 die_errno("cannot open pid file '%s'", path);
 904         if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
 905                 die_errno("failed to write pid file '%s'", path);
 906 }
 907
 908 static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
 909 {
 910         int socknum, *socklist;
 911
 912         socknum = socksetup(listen_addr, listen_port, &socklist);
 913         if (socknum == 0)
 914                 die("unable to allocate any listen sockets on host %s port %u",
 915                     listen_addr, listen_port);
 916
 917         if (pass && gid &&
 918             (initgroups(pass->pw_name, gid) || setgid (gid) ||
 919              setuid(pass->pw_uid)))
 920                 die("cannot drop privileges");
 921
 922         return service_loop(socknum, socklist);
 923 }
 924
 925 int main(int argc, char **argv)
 926 {
 927         int listen_port = 0;
 928         char *listen_addr = NULL;
 929         int inetd_mode = 0;
 930         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
 931         int detach = 0;
 932         struct passwd *pass = NULL;
 933         struct group *group;
 934         gid_t gid = 0;
 935         int i;
 936
 937         git_extract_argv0_path(argv[0]);
 938
 939         for (i = 1; i < argc; i++) {
 940                 char *arg = argv[i];
 941
 942                 if (!prefixcmp(arg, "--listen=")) {
 943                         listen_addr = xstrdup_tolower(arg + 9);
 944                         continue;
 945                 }
 946                 if (!prefixcmp(arg, "--port=")) {
 947                         char *end;
 948                         unsigned long n;
 949                         n = strtoul(arg+7, &end, 0);
 950                         if (arg[7] && !*end) {
 951                                 listen_port = n;
 952                                 continue;
 953                         }
 954                 }
 955                 if (!strcmp(arg, "--inetd")) {
 956                         inetd_mode = 1;
 957                         log_syslog = 1;
 958                         continue;
 959                 }
 960                 if (!strcmp(arg, "--verbose")) {
 961                         verbose = 1;
 962                         continue;
 963                 }
 964                 if (!strcmp(arg, "--syslog")) {
 965                         log_syslog = 1;
 966                         continue;
 967                 }
 968                 if (!strcmp(arg, "--export-all")) {
 969                         export_all_trees = 1;
 970                         continue;
 971                 }
 972                 if (!prefixcmp(arg, "--timeout=")) {
 973                         timeout = atoi(arg+10);
 974                         continue;
 975                 }
 976                 if (!prefixcmp(arg, "--init-timeout=")) {
 977                         init_timeout = atoi(arg+15);
 978                         continue;
 979                 }
 980                 if (!prefixcmp(arg, "--max-connections=")) {
 981                         max_connections = atoi(arg+18);
 982                         if (max_connections < 0)
 983                                 max_connections = 0;            /* unlimited */
 984                         continue;
 985                 }
 986                 if (!strcmp(arg, "--strict-paths")) {
 987                         strict_paths = 1;
 988                         continue;
 989                 }
 990                 if (!prefixcmp(arg, "--base-path=")) {
 991                         base_path = arg+12;
 992                         continue;
 993                 }
 994                 if (!strcmp(arg, "--base-path-relaxed")) {
 995                         base_path_relaxed = 1;
 996                         continue;
 997                 }
 998                 if (!prefixcmp(arg, "--interpolated-path=")) {
 999                         interpolated_path = arg+20;
1000                         continue;
1001                 }
1002                 if (!strcmp(arg, "--reuseaddr")) {
1003                         reuseaddr = 1;
1004                         continue;
1005                 }
1006                 if (!strcmp(arg, "--user-path")) {
1007                         user_path = "";
1008                         continue;
1009                 }
1010                 if (!prefixcmp(arg, "--user-path=")) {
1011                         user_path = arg + 12;
1012                         continue;
1013                 }
1014                 if (!prefixcmp(arg, "--pid-file=")) {
1015                         pid_file = arg + 11;
1016                         continue;
1017                 }
1018                 if (!strcmp(arg, "--detach")) {
1019                         detach = 1;
1020                         log_syslog = 1;
1021                         continue;
1022                 }
1023                 if (!prefixcmp(arg, "--user=")) {
1024                         user_name = arg + 7;
1025                         continue;
1026                 }
1027                 if (!prefixcmp(arg, "--group=")) {
1028                         group_name = arg + 8;
1029                         continue;
1030                 }
1031                 if (!prefixcmp(arg, "--enable=")) {
1032                         enable_service(arg + 9, 1);
1033                         continue;
1034                 }
1035                 if (!prefixcmp(arg, "--disable=")) {
1036                         enable_service(arg + 10, 0);
1037                         continue;
1038                 }
1039                 if (!prefixcmp(arg, "--allow-override=")) {
1040                         make_service_overridable(arg + 17, 1);
1041                         continue;
1042                 }
1043                 if (!prefixcmp(arg, "--forbid-override=")) {
1044                         make_service_overridable(arg + 18, 0);
1045                         continue;
1046                 }
1047                 if (!strcmp(arg, "--")) {
1048                         ok_paths = &argv[i+1];
1049                         break;
1050                 } else if (arg[0] != '-') {
1051                         ok_paths = &argv[i];
1052                         break;
1053                 }
1054
1055                 usage(daemon_usage);
1056         }
1057
1058         if (log_syslog) {
1059                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1060                 set_die_routine(daemon_die);
1061         } else
1062                 /* avoid splitting a message in the middle */
1063                 setvbuf(stderr, NULL, _IOLBF, 0);
1064
1065         if (inetd_mode && (group_name || user_name))
1066                 die("--user and --group are incompatible with --inetd");
1067
1068         if (inetd_mode && (listen_port || listen_addr))
1069                 die("--listen= and --port= are incompatible with --inetd");
1070         else if (listen_port == 0)
1071                 listen_port = DEFAULT_GIT_PORT;
1072
1073         if (group_name && !user_name)
1074                 die("--group supplied without --user");
1075
1076         if (user_name) {
1077                 pass = getpwnam(user_name);
1078                 if (!pass)
1079                         die("user not found - %s", user_name);
1080
1081                 if (!group_name)
1082                         gid = pass->pw_gid;
1083                 else {
1084                         group = getgrnam(group_name);
1085                         if (!group)
1086                                 die("group not found - %s", group_name);
1087
1088                         gid = group->gr_gid;
1089                 }
1090         }
1091
1092         if (strict_paths && (!ok_paths || !*ok_paths))
1093                 die("option --strict-paths requires a whitelist");
1094
1095         if (base_path && !is_directory(base_path))
1096                 die("base-path '%s' does not exist or is not a directory",
1097                     base_path);
1098
1099         if (inetd_mode) {
1100                 struct sockaddr_storage ss;
1101                 struct sockaddr *peer = (struct sockaddr *)&ss;
1102                 socklen_t slen = sizeof(ss);
1103
1104                 if (!freopen("/dev/null", "w", stderr))
1105                         die_errno("failed to redirect stderr to /dev/null");
1106
1107                 if (getpeername(0, peer, &slen))
1108                         peer = NULL;
1109
1110                 return execute(peer);
1111         }
1112
1113         if (detach) {
1114                 daemonize();
1115                 loginfo("Ready to rumble");
1116         }
1117         else
1118                 sanitize_stdfds();
1119
1120         if (pid_file)
1121                 store_pid(pid_file);
1122
1123         return serve(listen_addr, listen_port, pass, gid);
1124 }