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 int avoid_alias(char *p)
 107 {
 108         int sl, ndot;
 109
 110         /*
 111          * This resurrects the belts and suspenders paranoia check by HPA
 112          * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
 113          * does not do getcwd() based path canonicalizations.
 114          *
 115          * sl becomes true immediately after seeing '/' and continues to
 116          * be true as long as dots continue after that without intervening
 117          * non-dot character.
 118          */
 119         if (!p || (*p != '/' && *p != '~'))
 120                 return -1;
 121         sl = 1; ndot = 0;
 122         p++;
 123
 124         while (1) {
 125                 char ch = *p++;
 126                 if (sl) {
 127                         if (ch == '.')
 128                                 ndot++;
 129                         else if (ch == '/') {
 130                                 if (ndot < 3)
 131                                         /* reject //, /./ and /../ */
 132                                         return -1;
 133                                 ndot = 0;
 134                         }
 135                         else if (ch == 0) {
 136                                 if (0 < ndot && ndot < 3)
 137                                         /* reject /.$ and /..$ */
 138                                         return -1;
 139                                 return 0;
 140                         }
 141                         else
 142                                 sl = ndot = 0;
 143                 }
 144                 else if (ch == 0)
 145                         return 0;
 146                 else if (ch == '/') {
 147                         sl = 1;
 148                         ndot = 0;
 149                 }
 150         }
 151 }
 152
 153 static char *path_ok(char *directory)
 154 {
 155         static char rpath[PATH_MAX];
 156         static char interp_path[PATH_MAX];
 157         char *path;
 158         char *dir;
 159
 160         dir = directory;
 161
 162         if (avoid_alias(dir)) {
 163                 logerror("'%s': aliased", dir);
 164                 return NULL;
 165         }
 166
 167         if (*dir == '~') {
 168                 if (!user_path) {
 169                         logerror("'%s': User-path not allowed", dir);
 170                         return NULL;
 171                 }
 172                 if (*user_path) {
 173                         /* Got either "~alice" or "~alice/foo";
 174                          * rewrite them to "~alice/%s" or
 175                          * "~alice/%s/foo".
 176                          */
 177                         int namlen, restlen = strlen(dir);
 178                         char *slash = strchr(dir, '/');
 179                         if (!slash)
 180                                 slash = dir + restlen;
 181                         namlen = slash - dir;
 182                         restlen -= namlen;
 183                         loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
 184                         snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
 185                                  namlen, dir, user_path, restlen, slash);
 186                         dir = rpath;
 187                 }
 188         }
 189         else if (interpolated_path && saw_extended_args) {
 190                 struct strbuf expanded_path = STRBUF_INIT;
 191                 struct strbuf_expand_dict_entry dict[] = {
 192                         { "H", hostname },
 193                         { "CH", canon_hostname },
 194                         { "IP", ip_address },
 195                         { "P", tcp_port },
 196                         { "D", directory },
 197                         { "%", "%" },
 198                         { NULL }
 199                 };
 200
 201                 if (*dir != '/') {
 202                         /* Allow only absolute */
 203                         logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 204                         return NULL;
 205                 }
 206
 207                 strbuf_expand(&expanded_path, interpolated_path,
 208                                 strbuf_expand_dict_cb, &dict);
 209                 strlcpy(interp_path, expanded_path.buf, PATH_MAX);
 210                 strbuf_release(&expanded_path);
 211                 loginfo("Interpolated dir '%s'", interp_path);
 212
 213                 dir = interp_path;
 214         }
 215         else if (base_path) {
 216                 if (*dir != '/') {
 217                         /* Allow only absolute */
 218                         logerror("'%s': Non-absolute path denied (base-path active)", dir);
 219                         return NULL;
 220                 }
 221                 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
 222                 dir = rpath;
 223         }
 224
 225         path = enter_repo(dir, strict_paths);
 226         if (!path && base_path && base_path_relaxed) {
 227                 /*
 228                  * if we fail and base_path_relaxed is enabled, try without
 229                  * prefixing the base path
 230                  */
 231                 dir = directory;
 232                 path = enter_repo(dir, strict_paths);
 233         }
 234
 235         if (!path) {
 236                 logerror("'%s' does not appear to be a git repository", dir);
 237                 return NULL;
 238         }
 239
 240         if ( ok_paths && *ok_paths ) {
 241                 char **pp;
 242                 int pathlen = strlen(path);
 243
 244                 /* The validation is done on the paths after enter_repo
 245                  * appends optional {.git,.git/.git} and friends, but
 246                  * it does not use getcwd().  So if your /pub is
 247                  * a symlink to /mnt/pub, you can whitelist /pub and
 248                  * do not have to say /mnt/pub.
 249                  * Do not say /pub/.
 250                  */
 251                 for ( pp = ok_paths ; *pp ; pp++ ) {
 252                         int len = strlen(*pp);
 253                         if (len <= pathlen &&
 254                             !memcmp(*pp, path, len) &&
 255                             (path[len] == '\0' ||
 256                              (!strict_paths && path[len] == '/')))
 257                                 return path;
 258                 }
 259         }
 260         else {
 261                 /* be backwards compatible */
 262                 if (!strict_paths)
 263                         return path;
 264         }
 265
 266         logerror("'%s': not in whitelist", path);
 267         return NULL;            /* Fallthrough. Deny by default */
 268 }
 269
 270 typedef int (*daemon_service_fn)(void);
 271 struct daemon_service {
 272         const char *name;
 273         const char *config_name;
 274         daemon_service_fn fn;
 275         int enabled;
 276         int overridable;
 277 };
 278
 279 static struct daemon_service *service_looking_at;
 280 static int service_enabled;
 281
 282 static int git_daemon_config(const char *var, const char *value, void *cb)
 283 {
 284         if (!prefixcmp(var, "daemon.") &&
 285             !strcmp(var + 7, service_looking_at->config_name)) {
 286                 service_enabled = git_config_bool(var, value);
 287                 return 0;
 288         }
 289
 290         /* we are not interested in parsing any other configuration here */
 291         return 0;
 292 }
 293
 294 static int run_service(char *dir, struct daemon_service *service)
 295 {
 296         const char *path;
 297         int enabled = service->enabled;
 298
 299         loginfo("Request %s for '%s'", service->name, dir);
 300
 301         if (!enabled && !service->overridable) {
 302                 logerror("'%s': service not enabled.", service->name);
 303                 errno = EACCES;
 304                 return -1;
 305         }
 306
 307         if (!(path = path_ok(dir)))
 308                 return -1;
 309
 310         /*
 311          * Security on the cheap.
 312          *
 313          * We want a readable HEAD, usable "objects" directory, and
 314          * a "git-daemon-export-ok" flag that says that the other side
 315          * is ok with us doing this.
 316          *
 317          * path_ok() uses enter_repo() and does whitelist checking.
 318          * We only need to make sure the repository is exported.
 319          */
 320
 321         if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 322                 logerror("'%s': repository not exported.", path);
 323                 errno = EACCES;
 324                 return -1;
 325         }
 326
 327         if (service->overridable) {
 328                 service_looking_at = service;
 329                 service_enabled = -1;
 330                 git_config(git_daemon_config, NULL);
 331                 if (0 <= service_enabled)
 332                         enabled = service_enabled;
 333         }
 334         if (!enabled) {
 335                 logerror("'%s': service not enabled for '%s'",
 336                          service->name, path);
 337                 errno = EACCES;
 338                 return -1;
 339         }
 340
 341         /*
 342          * We'll ignore SIGTERM from now on, we have a
 343          * good client.
 344          */
 345         signal(SIGTERM, SIG_IGN);
 346
 347         return service->fn();
 348 }
 349
 350 static void copy_to_log(int fd)
 351 {
 352         struct strbuf line = STRBUF_INIT;
 353         FILE *fp;
 354
 355         fp = fdopen(fd, "r");
 356         if (fp == NULL) {
 357                 logerror("fdopen of error channel failed");
 358                 close(fd);
 359                 return;
 360         }
 361
 362         while (strbuf_getline(&line, fp, '\n') != EOF) {
 363                 logerror("%s", line.buf);
 364                 strbuf_setlen(&line, 0);
 365         }
 366
 367         strbuf_release(&line);
 368         fclose(fp);
 369 }
 370
 371 static int run_service_command(const char **argv)
 372 {
 373         struct child_process cld;
 374
 375         memset(&cld, 0, sizeof(cld));
 376         cld.argv = argv;
 377         cld.git_cmd = 1;
 378         cld.err = -1;
 379         if (start_command(&cld))
 380                 return -1;
 381
 382         close(0);
 383         close(1);
 384
 385         copy_to_log(cld.err);
 386
 387         return finish_command(&cld);
 388 }
 389
 390 static int upload_pack(void)
 391 {
 392         /* Timeout as string */
 393         char timeout_buf[64];
 394         const char *argv[] = { "upload-pack", "--strict", timeout_buf, ".", NULL };
 395
 396         snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 397         return run_service_command(argv);
 398 }
 399
 400 static int upload_archive(void)
 401 {
 402         static const char *argv[] = { "upload-archive", ".", NULL };
 403         return run_service_command(argv);
 404 }
 405
 406 static int receive_pack(void)
 407 {
 408         static const char *argv[] = { "receive-pack", ".", NULL };
 409         return run_service_command(argv);
 410 }
 411
 412 static struct daemon_service daemon_service[] = {
 413         { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 414         { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 415         { "receive-pack", "receivepack", receive_pack, 0, 1 },
 416 };
 417
 418 static void enable_service(const char *name, int ena)
 419 {
 420         int i;
 421         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 422                 if (!strcmp(daemon_service[i].name, name)) {
 423                         daemon_service[i].enabled = ena;
 424                         return;
 425                 }
 426         }
 427         die("No such service %s", name);
 428 }
 429
 430 static void make_service_overridable(const char *name, int ena)
 431 {
 432         int i;
 433         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 434                 if (!strcmp(daemon_service[i].name, name)) {
 435                         daemon_service[i].overridable = ena;
 436                         return;
 437                 }
 438         }
 439         die("No such service %s", name);
 440 }
 441
 442 static char *xstrdup_tolower(const char *str)
 443 {
 444         char *p, *dup = xstrdup(str);
 445         for (p = dup; *p; p++)
 446                 *p = tolower(*p);
 447         return dup;
 448 }
 449
 450 /*
 451  * Read the host as supplied by the client connection.
 452  */
 453 static void parse_host_arg(char *extra_args, int buflen)
 454 {
 455         char *val;
 456         int vallen;
 457         char *end = extra_args + buflen;
 458
 459         if (extra_args < end && *extra_args) {
 460                 saw_extended_args = 1;
 461                 if (strncasecmp("host=", extra_args, 5) == 0) {
 462                         val = extra_args + 5;
 463                         vallen = strlen(val) + 1;
 464                         if (*val) {
 465                                 /* Split <host>:<port> at colon. */
 466                                 char *host = val;
 467                                 char *port = strrchr(host, ':');
 468                                 if (port) {
 469                                         *port = 0;
 470                                         port++;
 471                                         free(tcp_port);
 472                                         tcp_port = xstrdup(port);
 473                                 }
 474                                 free(hostname);
 475                                 hostname = xstrdup_tolower(host);
 476                         }
 477
 478                         /* On to the next one */
 479                         extra_args = val + vallen;
 480                 }
 481                 if (extra_args < end && *extra_args)
 482                         die("Invalid request");
 483         }
 484
 485         /*
 486          * Locate canonical hostname and its IP address.
 487          */
 488         if (hostname) {
 489 #ifndef NO_IPV6
 490                 struct addrinfo hints;
 491                 struct addrinfo *ai;
 492                 int gai;
 493                 static char addrbuf[HOST_NAME_MAX + 1];
 494
 495                 memset(&hints, 0, sizeof(hints));
 496                 hints.ai_flags = AI_CANONNAME;
 497
 498                 gai = getaddrinfo(hostname, NULL, &hints, &ai);
 499                 if (!gai) {
 500                         struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 501
 502                         inet_ntop(AF_INET, &sin_addr->sin_addr,
 503                                   addrbuf, sizeof(addrbuf));
 504                         free(ip_address);
 505                         ip_address = xstrdup(addrbuf);
 506
 507                         free(canon_hostname);
 508                         canon_hostname = xstrdup(ai->ai_canonname ?
 509                                                  ai->ai_canonname : ip_address);
 510
 511                         freeaddrinfo(ai);
 512                 }
 513 #else
 514                 struct hostent *hent;
 515                 struct sockaddr_in sa;
 516                 char **ap;
 517                 static char addrbuf[HOST_NAME_MAX + 1];
 518
 519                 hent = gethostbyname(hostname);
 520
 521                 ap = hent->h_addr_list;
 522                 memset(&sa, 0, sizeof sa);
 523                 sa.sin_family = hent->h_addrtype;
 524                 sa.sin_port = htons(0);
 525                 memcpy(&sa.sin_addr, *ap, hent->h_length);
 526
 527                 inet_ntop(hent->h_addrtype, &sa.sin_addr,
 528                           addrbuf, sizeof(addrbuf));
 529
 530                 free(canon_hostname);
 531                 canon_hostname = xstrdup(hent->h_name);
 532                 free(ip_address);
 533                 ip_address = xstrdup(addrbuf);
 534 #endif
 535         }
 536 }
 537
 538
 539 static int execute(struct sockaddr *addr)
 540 {
 541         static char line[1000];
 542         int pktlen, len, i;
 543
 544         if (addr) {
 545                 char addrbuf[256] = "";
 546                 int port = -1;
 547
 548                 if (addr->sa_family == AF_INET) {
 549                         struct sockaddr_in *sin_addr = (void *) addr;
 550                         inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
 551                         port = ntohs(sin_addr->sin_port);
 552 #ifndef NO_IPV6
 553                 } else if (addr && addr->sa_family == AF_INET6) {
 554                         struct sockaddr_in6 *sin6_addr = (void *) addr;
 555
 556                         char *buf = addrbuf;
 557                         *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 558                         inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
 559                         strcat(buf, "]");
 560
 561                         port = ntohs(sin6_addr->sin6_port);
 562 #endif
 563                 }
 564                 loginfo("Connection from %s:%d", addrbuf, port);
 565                 setenv("REMOTE_ADDR", addrbuf, 1);
 566         }
 567         else {
 568                 unsetenv("REMOTE_ADDR");
 569         }
 570
 571         alarm(init_timeout ? init_timeout : timeout);
 572         pktlen = packet_read_line(0, line, sizeof(line));
 573         alarm(0);
 574
 575         len = strlen(line);
 576         if (pktlen != len)
 577                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
 578                         (int) pktlen - len,
 579                         (int) pktlen - len, line + len + 1);
 580         if (len && line[len-1] == '\n') {
 581                 line[--len] = 0;
 582                 pktlen--;
 583         }
 584
 585         free(hostname);
 586         free(canon_hostname);
 587         free(ip_address);
 588         free(tcp_port);
 589         hostname = canon_hostname = ip_address = tcp_port = NULL;
 590
 591         if (len != pktlen)
 592                 parse_host_arg(line + len + 1, pktlen - len - 1);
 593
 594         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 595                 struct daemon_service *s = &(daemon_service[i]);
 596                 int namelen = strlen(s->name);
 597                 if (!prefixcmp(line, "git-") &&
 598                     !strncmp(s->name, line + 4, namelen) &&
 599                     line[namelen + 4] == ' ') {
 600                         /*
 601                          * Note: The directory here is probably context sensitive,
 602                          * and might depend on the actual service being performed.
 603                          */
 604                         return run_service(line + namelen + 5, s);
 605                 }
 606         }
 607
 608         logerror("Protocol error: '%s'", line);
 609         return -1;
 610 }
 611
 612 static int max_connections = 32;
 613
 614 static unsigned int live_children;
 615
 616 static struct child {
 617         struct child *next;
 618         pid_t pid;
 619         struct sockaddr_storage address;
 620 } *firstborn;
 621
 622 static void add_child(pid_t pid, struct sockaddr *addr, int addrlen)
 623 {
 624         struct child *newborn, **cradle;
 625
 626         /*
 627          * This must be xcalloc() -- we'll compare the whole sockaddr_storage
 628          * but individual address may be shorter.
 629          */
 630         newborn = xcalloc(1, sizeof(*newborn));
 631         live_children++;
 632         newborn->pid = pid;
 633         memcpy(&newborn->address, addr, addrlen);
 634         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 635                 if (!memcmp(&(*cradle)->address, &newborn->address,
 636                             sizeof(newborn->address)))
 637                         break;
 638         newborn->next = *cradle;
 639         *cradle = newborn;
 640 }
 641
 642 static void remove_child(pid_t pid)
 643 {
 644         struct child **cradle, *blanket;
 645
 646         for (cradle = &firstborn; (blanket = *cradle); cradle = &blanket->next)
 647                 if (blanket->pid == pid) {
 648                         *cradle = blanket->next;
 649                         live_children--;
 650                         free(blanket);
 651                         break;
 652                 }
 653 }
 654
 655 /*
 656  * This gets called if the number of connections grows
 657  * past "max_connections".
 658  *
 659  * We kill the newest connection from a duplicate IP.
 660  */
 661 static void kill_some_child(void)
 662 {
 663         const struct child *blanket, *next;
 664
 665         if (!(blanket = firstborn))
 666                 return;
 667
 668         for (; (next = blanket->next); blanket = next)
 669                 if (!memcmp(&blanket->address, &next->address,
 670                             sizeof(next->address))) {
 671                         kill(blanket->pid, SIGTERM);
 672                         break;
 673                 }
 674 }
 675
 676 static void check_dead_children(void)
 677 {
 678         int status;
 679         pid_t pid;
 680
 681         while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
 682                 const char *dead = "";
 683                 remove_child(pid);
 684                 if (!WIFEXITED(status) || (WEXITSTATUS(status) > 0))
 685                         dead = " (with error)";
 686                 loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 687         }
 688 }
 689
 690 static void handle(int incoming, struct sockaddr *addr, int addrlen)
 691 {
 692         pid_t pid;
 693
 694         if (max_connections && live_children >= max_connections) {
 695                 kill_some_child();
 696                 sleep(1);  /* give it some time to die */
 697                 check_dead_children();
 698                 if (live_children >= max_connections) {
 699                         close(incoming);
 700                         logerror("Too many children, dropping connection");
 701                         return;
 702                 }
 703         }
 704
 705         if ((pid = fork())) {
 706                 close(incoming);
 707                 if (pid < 0) {
 708                         logerror("Couldn't fork %s", strerror(errno));
 709                         return;
 710                 }
 711
 712                 add_child(pid, addr, addrlen);
 713                 return;
 714         }
 715
 716         dup2(incoming, 0);
 717         dup2(incoming, 1);
 718         close(incoming);
 719
 720         exit(execute(addr));
 721 }
 722
 723 static void child_handler(int signo)
 724 {
 725         /*
 726          * Otherwise empty handler because systemcalls will get interrupted
 727          * upon signal receipt
 728          * SysV needs the handler to be rearmed
 729          */
 730         signal(SIGCHLD, child_handler);
 731 }
 732
 733 static int set_reuse_addr(int sockfd)
 734 {
 735         int on = 1;
 736
 737         if (!reuseaddr)
 738                 return 0;
 739         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 740                           &on, sizeof(on));
 741 }
 742
 743 #ifndef NO_IPV6
 744
 745 static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 746 {
 747         int socknum = 0, *socklist = NULL;
 748         int maxfd = -1;
 749         char pbuf[NI_MAXSERV];
 750         struct addrinfo hints, *ai0, *ai;
 751         int gai;
 752         long flags;
 753
 754         sprintf(pbuf, "%d", listen_port);
 755         memset(&hints, 0, sizeof(hints));
 756         hints.ai_family = AF_UNSPEC;
 757         hints.ai_socktype = SOCK_STREAM;
 758         hints.ai_protocol = IPPROTO_TCP;
 759         hints.ai_flags = AI_PASSIVE;
 760
 761         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 762         if (gai)
 763                 die("getaddrinfo() failed: %s", gai_strerror(gai));
 764
 765         for (ai = ai0; ai; ai = ai->ai_next) {
 766                 int sockfd;
 767
 768                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 769                 if (sockfd < 0)
 770                         continue;
 771                 if (sockfd >= FD_SETSIZE) {
 772                         logerror("Socket descriptor too large");
 773                         close(sockfd);
 774                         continue;
 775                 }
 776
 777 #ifdef IPV6_V6ONLY
 778                 if (ai->ai_family == AF_INET6) {
 779                         int on = 1;
 780                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 781                                    &on, sizeof(on));
 782                         /* Note: error is not fatal */
 783                 }
 784 #endif
 785
 786                 if (set_reuse_addr(sockfd)) {
 787                         close(sockfd);
 788                         continue;
 789                 }
 790
 791                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 792                         close(sockfd);
 793                         continue;       /* not fatal */
 794                 }
 795                 if (listen(sockfd, 5) < 0) {
 796                         close(sockfd);
 797                         continue;       /* not fatal */
 798                 }
 799
 800                 flags = fcntl(sockfd, F_GETFD, 0);
 801                 if (flags >= 0)
 802                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 803
 804                 socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
 805                 socklist[socknum++] = sockfd;
 806
 807                 if (maxfd < sockfd)
 808                         maxfd = sockfd;
 809         }
 810
 811         freeaddrinfo(ai0);
 812
 813         *socklist_p = socklist;
 814         return socknum;
 815 }
 816
 817 #else /* NO_IPV6 */
 818
 819 static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 820 {
 821         struct sockaddr_in sin;
 822         int sockfd;
 823         long flags;
 824
 825         memset(&sin, 0, sizeof sin);
 826         sin.sin_family = AF_INET;
 827         sin.sin_port = htons(listen_port);
 828
 829         if (listen_addr) {
 830                 /* Well, host better be an IP address here. */
 831                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 832                         return 0;
 833         } else {
 834                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
 835         }
 836
 837         sockfd = socket(AF_INET, SOCK_STREAM, 0);
 838         if (sockfd < 0)
 839                 return 0;
 840
 841         if (set_reuse_addr(sockfd)) {
 842                 close(sockfd);
 843                 return 0;
 844         }
 845
 846         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 847                 close(sockfd);
 848                 return 0;
 849         }
 850
 851         if (listen(sockfd, 5) < 0) {
 852                 close(sockfd);
 853                 return 0;
 854         }
 855
 856         flags = fcntl(sockfd, F_GETFD, 0);
 857         if (flags >= 0)
 858                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 859
 860         *socklist_p = xmalloc(sizeof(int));
 861         **socklist_p = sockfd;
 862         return 1;
 863 }
 864
 865 #endif
 866
 867 static int service_loop(int socknum, int *socklist)
 868 {
 869         struct pollfd *pfd;
 870         int i;
 871
 872         pfd = xcalloc(socknum, sizeof(struct pollfd));
 873
 874         for (i = 0; i < socknum; i++) {
 875                 pfd[i].fd = socklist[i];
 876                 pfd[i].events = POLLIN;
 877         }
 878
 879         signal(SIGCHLD, child_handler);
 880
 881         for (;;) {
 882                 int i;
 883
 884                 check_dead_children();
 885
 886                 if (poll(pfd, socknum, -1) < 0) {
 887                         if (errno != EINTR) {
 888                                 logerror("Poll failed, resuming: %s",
 889                                       strerror(errno));
 890                                 sleep(1);
 891                         }
 892                         continue;
 893                 }
 894
 895                 for (i = 0; i < socknum; i++) {
 896                         if (pfd[i].revents & POLLIN) {
 897                                 struct sockaddr_storage ss;
 898                                 unsigned int sslen = sizeof(ss);
 899                                 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
 900                                 if (incoming < 0) {
 901                                         switch (errno) {
 902                                         case EAGAIN:
 903                                         case EINTR:
 904                                         case ECONNABORTED:
 905                                                 continue;
 906                                         default:
 907                                                 die_errno("accept returned");
 908                                         }
 909                                 }
 910                                 handle(incoming, (struct sockaddr *)&ss, sslen);
 911                         }
 912                 }
 913         }
 914 }
 915
 916 /* if any standard file descriptor is missing open it to /dev/null */
 917 static void sanitize_stdfds(void)
 918 {
 919         int fd = open("/dev/null", O_RDWR, 0);
 920         while (fd != -1 && fd < 2)
 921                 fd = dup(fd);
 922         if (fd == -1)
 923                 die_errno("open /dev/null or dup failed");
 924         if (fd > 2)
 925                 close(fd);
 926 }
 927
 928 static void daemonize(void)
 929 {
 930         switch (fork()) {
 931                 case 0:
 932                         break;
 933                 case -1:
 934                         die_errno("fork failed");
 935                 default:
 936                         exit(0);
 937         }
 938         if (setsid() == -1)
 939                 die_errno("setsid failed");
 940         close(0);
 941         close(1);
 942         close(2);
 943         sanitize_stdfds();
 944 }
 945
 946 static void store_pid(const char *path)
 947 {
 948         FILE *f = fopen(path, "w");
 949         if (!f)
 950                 die_errno("cannot open pid file '%s'", path);
 951         if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
 952                 die_errno("failed to write pid file '%s'", path);
 953 }
 954
 955 static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
 956 {
 957         int socknum, *socklist;
 958
 959         socknum = socksetup(listen_addr, listen_port, &socklist);
 960         if (socknum == 0)
 961                 die("unable to allocate any listen sockets on host %s port %u",
 962                     listen_addr, listen_port);
 963
 964         if (pass && gid &&
 965             (initgroups(pass->pw_name, gid) || setgid (gid) ||
 966              setuid(pass->pw_uid)))
 967                 die("cannot drop privileges");
 968
 969         return service_loop(socknum, socklist);
 970 }
 971
 972 int main(int argc, char **argv)
 973 {
 974         int listen_port = 0;
 975         char *listen_addr = NULL;
 976         int inetd_mode = 0;
 977         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
 978         int detach = 0;
 979         struct passwd *pass = NULL;
 980         struct group *group;
 981         gid_t gid = 0;
 982         int i;
 983
 984         git_extract_argv0_path(argv[0]);
 985
 986         for (i = 1; i < argc; i++) {
 987                 char *arg = argv[i];
 988
 989                 if (!prefixcmp(arg, "--listen=")) {
 990                         listen_addr = xstrdup_tolower(arg + 9);
 991                         continue;
 992                 }
 993                 if (!prefixcmp(arg, "--port=")) {
 994                         char *end;
 995                         unsigned long n;
 996                         n = strtoul(arg+7, &end, 0);
 997                         if (arg[7] && !*end) {
 998                                 listen_port = n;
 999                                 continue;
1000                         }
1001                 }
1002                 if (!strcmp(arg, "--inetd")) {
1003                         inetd_mode = 1;
1004                         log_syslog = 1;
1005                         continue;
1006                 }
1007                 if (!strcmp(arg, "--verbose")) {
1008                         verbose = 1;
1009                         continue;
1010                 }
1011                 if (!strcmp(arg, "--syslog")) {
1012                         log_syslog = 1;
1013                         continue;
1014                 }
1015                 if (!strcmp(arg, "--export-all")) {
1016                         export_all_trees = 1;
1017                         continue;
1018                 }
1019                 if (!prefixcmp(arg, "--timeout=")) {
1020                         timeout = atoi(arg+10);
1021                         continue;
1022                 }
1023                 if (!prefixcmp(arg, "--init-timeout=")) {
1024                         init_timeout = atoi(arg+15);
1025                         continue;
1026                 }
1027                 if (!prefixcmp(arg, "--max-connections=")) {
1028                         max_connections = atoi(arg+18);
1029                         if (max_connections < 0)
1030                                 max_connections = 0;            /* unlimited */
1031                         continue;
1032                 }
1033                 if (!strcmp(arg, "--strict-paths")) {
1034                         strict_paths = 1;
1035                         continue;
1036                 }
1037                 if (!prefixcmp(arg, "--base-path=")) {
1038                         base_path = arg+12;
1039                         continue;
1040                 }
1041                 if (!strcmp(arg, "--base-path-relaxed")) {
1042                         base_path_relaxed = 1;
1043                         continue;
1044                 }
1045                 if (!prefixcmp(arg, "--interpolated-path=")) {
1046                         interpolated_path = arg+20;
1047                         continue;
1048                 }
1049                 if (!strcmp(arg, "--reuseaddr")) {
1050                         reuseaddr = 1;
1051                         continue;
1052                 }
1053                 if (!strcmp(arg, "--user-path")) {
1054                         user_path = "";
1055                         continue;
1056                 }
1057                 if (!prefixcmp(arg, "--user-path=")) {
1058                         user_path = arg + 12;
1059                         continue;
1060                 }
1061                 if (!prefixcmp(arg, "--pid-file=")) {
1062                         pid_file = arg + 11;
1063                         continue;
1064                 }
1065                 if (!strcmp(arg, "--detach")) {
1066                         detach = 1;
1067                         log_syslog = 1;
1068                         continue;
1069                 }
1070                 if (!prefixcmp(arg, "--user=")) {
1071                         user_name = arg + 7;
1072                         continue;
1073                 }
1074                 if (!prefixcmp(arg, "--group=")) {
1075                         group_name = arg + 8;
1076                         continue;
1077                 }
1078                 if (!prefixcmp(arg, "--enable=")) {
1079                         enable_service(arg + 9, 1);
1080                         continue;
1081                 }
1082                 if (!prefixcmp(arg, "--disable=")) {
1083                         enable_service(arg + 10, 0);
1084                         continue;
1085                 }
1086                 if (!prefixcmp(arg, "--allow-override=")) {
1087                         make_service_overridable(arg + 17, 1);
1088                         continue;
1089                 }
1090                 if (!prefixcmp(arg, "--forbid-override=")) {
1091                         make_service_overridable(arg + 18, 0);
1092                         continue;
1093                 }
1094                 if (!strcmp(arg, "--")) {
1095                         ok_paths = &argv[i+1];
1096                         break;
1097                 } else if (arg[0] != '-') {
1098                         ok_paths = &argv[i];
1099                         break;
1100                 }
1101
1102                 usage(daemon_usage);
1103         }
1104
1105         if (log_syslog) {
1106                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1107                 set_die_routine(daemon_die);
1108         } else
1109                 /* avoid splitting a message in the middle */
1110                 setvbuf(stderr, NULL, _IOLBF, 0);
1111
1112         if (inetd_mode && (group_name || user_name))
1113                 die("--user and --group are incompatible with --inetd");
1114
1115         if (inetd_mode && (listen_port || listen_addr))
1116                 die("--listen= and --port= are incompatible with --inetd");
1117         else if (listen_port == 0)
1118                 listen_port = DEFAULT_GIT_PORT;
1119
1120         if (group_name && !user_name)
1121                 die("--group supplied without --user");
1122
1123         if (user_name) {
1124                 pass = getpwnam(user_name);
1125                 if (!pass)
1126                         die("user not found - %s", user_name);
1127
1128                 if (!group_name)
1129                         gid = pass->pw_gid;
1130                 else {
1131                         group = getgrnam(group_name);
1132                         if (!group)
1133                                 die("group not found - %s", group_name);
1134
1135                         gid = group->gr_gid;
1136                 }
1137         }
1138
1139         if (strict_paths && (!ok_paths || !*ok_paths))
1140                 die("option --strict-paths requires a whitelist");
1141
1142         if (base_path && !is_directory(base_path))
1143                 die("base-path '%s' does not exist or is not a directory",
1144                     base_path);
1145
1146         if (inetd_mode) {
1147                 struct sockaddr_storage ss;
1148                 struct sockaddr *peer = (struct sockaddr *)&ss;
1149                 socklen_t slen = sizeof(ss);
1150
1151                 if (!freopen("/dev/null", "w", stderr))
1152                         die_errno("failed to redirect stderr to /dev/null");
1153
1154                 if (getpeername(0, peer, &slen))
1155                         peer = NULL;
1156
1157                 return execute(peer);
1158         }
1159
1160         if (detach) {
1161                 daemonize();
1162                 loginfo("Ready to rumble");
1163         }
1164         else
1165                 sanitize_stdfds();
1166
1167         if (pid_file)
1168                 store_pid(pid_file);
1169
1170         return serve(listen_addr, listen_port, pass, gid);
1171 }