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