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 static void parse_host_and_port(char *hostport, char **host,
 403         char **port)
 404 {
 405         if (*hostport == '[') {
 406                 char *end;
 407
 408                 end = strchr(hostport, ']');
 409                 if (!end)
 410                         die("Invalid request ('[' without ']')");
 411                 *end = '\0';
 412                 *host = hostport + 1;
 413                 if (!end[1])
 414                         *port = NULL;
 415                 else if (end[1] == ':')
 416                         *port = end + 2;
 417                 else
 418                         die("Garbage after end of host part");
 419         } else {
 420                 *host = hostport;
 421                 *port = strrchr(hostport, ':');
 422                 if (*port) {
 423                         **port = '\0';
 424                         ++*port;
 425                 }
 426         }
 427 }
 428
 429 /*
 430  * Read the host as supplied by the client connection.
 431  */
 432 static void parse_host_arg(char *extra_args, int buflen)
 433 {
 434         char *val;
 435         int vallen;
 436         char *end = extra_args + buflen;
 437
 438         if (extra_args < end && *extra_args) {
 439                 saw_extended_args = 1;
 440                 if (strncasecmp("host=", extra_args, 5) == 0) {
 441                         val = extra_args + 5;
 442                         vallen = strlen(val) + 1;
 443                         if (*val) {
 444                                 /* Split <host>:<port> at colon. */
 445                                 char *host;
 446                                 char *port;
 447                                 parse_host_and_port(val, &host, &port);
 448                                 if (port) {
 449                                         free(tcp_port);
 450                                         tcp_port = xstrdup(port);
 451                                 }
 452                                 free(hostname);
 453                                 hostname = xstrdup_tolower(host);
 454                         }
 455
 456                         /* On to the next one */
 457                         extra_args = val + vallen;
 458                 }
 459                 if (extra_args < end && *extra_args)
 460                         die("Invalid request");
 461         }
 462
 463         /*
 464          * Locate canonical hostname and its IP address.
 465          */
 466         if (hostname) {
 467 #ifndef NO_IPV6
 468                 struct addrinfo hints;
 469                 struct addrinfo *ai;
 470                 int gai;
 471                 static char addrbuf[HOST_NAME_MAX + 1];
 472
 473                 memset(&hints, 0, sizeof(hints));
 474                 hints.ai_flags = AI_CANONNAME;
 475
 476                 gai = getaddrinfo(hostname, NULL, &hints, &ai);
 477                 if (!gai) {
 478                         struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 479
 480                         inet_ntop(AF_INET, &sin_addr->sin_addr,
 481                                   addrbuf, sizeof(addrbuf));
 482                         free(ip_address);
 483                         ip_address = xstrdup(addrbuf);
 484
 485                         free(canon_hostname);
 486                         canon_hostname = xstrdup(ai->ai_canonname ?
 487                                                  ai->ai_canonname : ip_address);
 488
 489                         freeaddrinfo(ai);
 490                 }
 491 #else
 492                 struct hostent *hent;
 493                 struct sockaddr_in sa;
 494                 char **ap;
 495                 static char addrbuf[HOST_NAME_MAX + 1];
 496
 497                 hent = gethostbyname(hostname);
 498
 499                 ap = hent->h_addr_list;
 500                 memset(&sa, 0, sizeof sa);
 501                 sa.sin_family = hent->h_addrtype;
 502                 sa.sin_port = htons(0);
 503                 memcpy(&sa.sin_addr, *ap, hent->h_length);
 504
 505                 inet_ntop(hent->h_addrtype, &sa.sin_addr,
 506                           addrbuf, sizeof(addrbuf));
 507
 508                 free(canon_hostname);
 509                 canon_hostname = xstrdup(hent->h_name);
 510                 free(ip_address);
 511                 ip_address = xstrdup(addrbuf);
 512 #endif
 513         }
 514 }
 515
 516
 517 static int execute(struct sockaddr *addr)
 518 {
 519         static char line[1000];
 520         int pktlen, len, i;
 521
 522         if (addr) {
 523                 char addrbuf[256] = "";
 524                 int port = -1;
 525
 526                 if (addr->sa_family == AF_INET) {
 527                         struct sockaddr_in *sin_addr = (void *) addr;
 528                         inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
 529                         port = ntohs(sin_addr->sin_port);
 530 #ifndef NO_IPV6
 531                 } else if (addr && addr->sa_family == AF_INET6) {
 532                         struct sockaddr_in6 *sin6_addr = (void *) addr;
 533
 534                         char *buf = addrbuf;
 535                         *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 536                         inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
 537                         strcat(buf, "]");
 538
 539                         port = ntohs(sin6_addr->sin6_port);
 540 #endif
 541                 }
 542                 loginfo("Connection from %s:%d", addrbuf, port);
 543                 setenv("REMOTE_ADDR", addrbuf, 1);
 544         }
 545         else {
 546                 unsetenv("REMOTE_ADDR");
 547         }
 548
 549         alarm(init_timeout ? init_timeout : timeout);
 550         pktlen = packet_read_line(0, line, sizeof(line));
 551         alarm(0);
 552
 553         len = strlen(line);
 554         if (pktlen != len)
 555                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
 556                         (int) pktlen - len,
 557                         (int) pktlen - len, line + len + 1);
 558         if (len && line[len-1] == '\n') {
 559                 line[--len] = 0;
 560                 pktlen--;
 561         }
 562
 563         free(hostname);
 564         free(canon_hostname);
 565         free(ip_address);
 566         free(tcp_port);
 567         hostname = canon_hostname = ip_address = tcp_port = NULL;
 568
 569         if (len != pktlen)
 570                 parse_host_arg(line + len + 1, pktlen - len - 1);
 571
 572         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 573                 struct daemon_service *s = &(daemon_service[i]);
 574                 int namelen = strlen(s->name);
 575                 if (!prefixcmp(line, "git-") &&
 576                     !strncmp(s->name, line + 4, namelen) &&
 577                     line[namelen + 4] == ' ') {
 578                         /*
 579                          * Note: The directory here is probably context sensitive,
 580                          * and might depend on the actual service being performed.
 581                          */
 582                         return run_service(line + namelen + 5, s);
 583                 }
 584         }
 585
 586         logerror("Protocol error: '%s'", line);
 587         return -1;
 588 }
 589
 590 static int addrcmp(const struct sockaddr_storage *s1,
 591     const struct sockaddr_storage *s2)
 592 {
 593         const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 594         const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 595
 596         if (sa1->sa_family != sa2->sa_family)
 597                 return sa1->sa_family - sa2->sa_family;
 598         if (sa1->sa_family == AF_INET)
 599                 return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 600                     &((struct sockaddr_in *)s2)->sin_addr,
 601                     sizeof(struct in_addr));
 602 #ifndef NO_IPV6
 603         if (sa1->sa_family == AF_INET6)
 604                 return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 605                     &((struct sockaddr_in6 *)s2)->sin6_addr,
 606                     sizeof(struct in6_addr));
 607 #endif
 608         return 0;
 609 }
 610
 611 static int max_connections = 32;
 612
 613 static unsigned int live_children;
 614
 615 static struct child {
 616         struct child *next;
 617         pid_t pid;
 618         struct sockaddr_storage address;
 619 } *firstborn;
 620
 621 static void add_child(pid_t pid, struct sockaddr *addr, int addrlen)
 622 {
 623         struct child *newborn, **cradle;
 624
 625         newborn = xcalloc(1, sizeof(*newborn));
 626         live_children++;
 627         newborn->pid = pid;
 628         memcpy(&newborn->address, addr, addrlen);
 629         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 630                 if (!addrcmp(&(*cradle)->address, &newborn->address))
 631                         break;
 632         newborn->next = *cradle;
 633         *cradle = newborn;
 634 }
 635
 636 static void remove_child(pid_t pid)
 637 {
 638         struct child **cradle, *blanket;
 639
 640         for (cradle = &firstborn; (blanket = *cradle); cradle = &blanket->next)
 641                 if (blanket->pid == pid) {
 642                         *cradle = blanket->next;
 643                         live_children--;
 644                         free(blanket);
 645                         break;
 646                 }
 647 }
 648
 649 /*
 650  * This gets called if the number of connections grows
 651  * past "max_connections".
 652  *
 653  * We kill the newest connection from a duplicate IP.
 654  */
 655 static void kill_some_child(void)
 656 {
 657         const struct child *blanket, *next;
 658
 659         if (!(blanket = firstborn))
 660                 return;
 661
 662         for (; (next = blanket->next); blanket = next)
 663                 if (!addrcmp(&blanket->address, &next->address)) {
 664                         kill(blanket->pid, SIGTERM);
 665                         break;
 666                 }
 667 }
 668
 669 static void check_dead_children(void)
 670 {
 671         int status;
 672         pid_t pid;
 673
 674         while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
 675                 const char *dead = "";
 676                 remove_child(pid);
 677                 if (!WIFEXITED(status) || (WEXITSTATUS(status) > 0))
 678                         dead = " (with error)";
 679                 loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 680         }
 681 }
 682
 683 static void handle(int incoming, struct sockaddr *addr, int addrlen)
 684 {
 685         pid_t pid;
 686
 687         if (max_connections && live_children >= max_connections) {
 688                 kill_some_child();
 689                 sleep(1);  /* give it some time to die */
 690                 check_dead_children();
 691                 if (live_children >= max_connections) {
 692                         close(incoming);
 693                         logerror("Too many children, dropping connection");
 694                         return;
 695                 }
 696         }
 697
 698         if ((pid = fork())) {
 699                 close(incoming);
 700                 if (pid < 0) {
 701                         logerror("Couldn't fork %s", strerror(errno));
 702                         return;
 703                 }
 704
 705                 add_child(pid, addr, addrlen);
 706                 return;
 707         }
 708
 709         dup2(incoming, 0);
 710         dup2(incoming, 1);
 711         close(incoming);
 712
 713         exit(execute(addr));
 714 }
 715
 716 static void child_handler(int signo)
 717 {
 718         /*
 719          * Otherwise empty handler because systemcalls will get interrupted
 720          * upon signal receipt
 721          * SysV needs the handler to be rearmed
 722          */
 723         signal(SIGCHLD, child_handler);
 724 }
 725
 726 static int set_reuse_addr(int sockfd)
 727 {
 728         int on = 1;
 729
 730         if (!reuseaddr)
 731                 return 0;
 732         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 733                           &on, sizeof(on));
 734 }
 735
 736 #ifndef NO_IPV6
 737
 738 static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 739 {
 740         int socknum = 0, *socklist = NULL;
 741         int maxfd = -1;
 742         char pbuf[NI_MAXSERV];
 743         struct addrinfo hints, *ai0, *ai;
 744         int gai;
 745         long flags;
 746
 747         sprintf(pbuf, "%d", listen_port);
 748         memset(&hints, 0, sizeof(hints));
 749         hints.ai_family = AF_UNSPEC;
 750         hints.ai_socktype = SOCK_STREAM;
 751         hints.ai_protocol = IPPROTO_TCP;
 752         hints.ai_flags = AI_PASSIVE;
 753
 754         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 755         if (gai)
 756                 die("getaddrinfo() failed: %s", gai_strerror(gai));
 757
 758         for (ai = ai0; ai; ai = ai->ai_next) {
 759                 int sockfd;
 760
 761                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 762                 if (sockfd < 0)
 763                         continue;
 764                 if (sockfd >= FD_SETSIZE) {
 765                         logerror("Socket descriptor too large");
 766                         close(sockfd);
 767                         continue;
 768                 }
 769
 770 #ifdef IPV6_V6ONLY
 771                 if (ai->ai_family == AF_INET6) {
 772                         int on = 1;
 773                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 774                                    &on, sizeof(on));
 775                         /* Note: error is not fatal */
 776                 }
 777 #endif
 778
 779                 if (set_reuse_addr(sockfd)) {
 780                         close(sockfd);
 781                         continue;
 782                 }
 783
 784                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 785                         close(sockfd);
 786                         continue;       /* not fatal */
 787                 }
 788                 if (listen(sockfd, 5) < 0) {
 789                         close(sockfd);
 790                         continue;       /* not fatal */
 791                 }
 792
 793                 flags = fcntl(sockfd, F_GETFD, 0);
 794                 if (flags >= 0)
 795                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 796
 797                 socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
 798                 socklist[socknum++] = sockfd;
 799
 800                 if (maxfd < sockfd)
 801                         maxfd = sockfd;
 802         }
 803
 804         freeaddrinfo(ai0);
 805
 806         *socklist_p = socklist;
 807         return socknum;
 808 }
 809
 810 #else /* NO_IPV6 */
 811
 812 static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 813 {
 814         struct sockaddr_in sin;
 815         int sockfd;
 816         long flags;
 817
 818         memset(&sin, 0, sizeof sin);
 819         sin.sin_family = AF_INET;
 820         sin.sin_port = htons(listen_port);
 821
 822         if (listen_addr) {
 823                 /* Well, host better be an IP address here. */
 824                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 825                         return 0;
 826         } else {
 827                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
 828         }
 829
 830         sockfd = socket(AF_INET, SOCK_STREAM, 0);
 831         if (sockfd < 0)
 832                 return 0;
 833
 834         if (set_reuse_addr(sockfd)) {
 835                 close(sockfd);
 836                 return 0;
 837         }
 838
 839         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 840                 close(sockfd);
 841                 return 0;
 842         }
 843
 844         if (listen(sockfd, 5) < 0) {
 845                 close(sockfd);
 846                 return 0;
 847         }
 848
 849         flags = fcntl(sockfd, F_GETFD, 0);
 850         if (flags >= 0)
 851                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 852
 853         *socklist_p = xmalloc(sizeof(int));
 854         **socklist_p = sockfd;
 855         return 1;
 856 }
 857
 858 #endif
 859
 860 static int service_loop(int socknum, int *socklist)
 861 {
 862         struct pollfd *pfd;
 863         int i;
 864
 865         pfd = xcalloc(socknum, sizeof(struct pollfd));
 866
 867         for (i = 0; i < socknum; i++) {
 868                 pfd[i].fd = socklist[i];
 869                 pfd[i].events = POLLIN;
 870         }
 871
 872         signal(SIGCHLD, child_handler);
 873
 874         for (;;) {
 875                 int i;
 876
 877                 check_dead_children();
 878
 879                 if (poll(pfd, socknum, -1) < 0) {
 880                         if (errno != EINTR) {
 881                                 logerror("Poll failed, resuming: %s",
 882                                       strerror(errno));
 883                                 sleep(1);
 884                         }
 885                         continue;
 886                 }
 887
 888                 for (i = 0; i < socknum; i++) {
 889                         if (pfd[i].revents & POLLIN) {
 890                                 struct sockaddr_storage ss;
 891                                 unsigned int sslen = sizeof(ss);
 892                                 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
 893                                 if (incoming < 0) {
 894                                         switch (errno) {
 895                                         case EAGAIN:
 896                                         case EINTR:
 897                                         case ECONNABORTED:
 898                                                 continue;
 899                                         default:
 900                                                 die_errno("accept returned");
 901                                         }
 902                                 }
 903                                 handle(incoming, (struct sockaddr *)&ss, sslen);
 904                         }
 905                 }
 906         }
 907 }
 908
 909 /* if any standard file descriptor is missing open it to /dev/null */
 910 static void sanitize_stdfds(void)
 911 {
 912         int fd = open("/dev/null", O_RDWR, 0);
 913         while (fd != -1 && fd < 2)
 914                 fd = dup(fd);
 915         if (fd == -1)
 916                 die_errno("open /dev/null or dup failed");
 917         if (fd > 2)
 918                 close(fd);
 919 }
 920
 921 static void daemonize(void)
 922 {
 923         switch (fork()) {
 924                 case 0:
 925                         break;
 926                 case -1:
 927                         die_errno("fork failed");
 928                 default:
 929                         exit(0);
 930         }
 931         if (setsid() == -1)
 932                 die_errno("setsid failed");
 933         close(0);
 934         close(1);
 935         close(2);
 936         sanitize_stdfds();
 937 }
 938
 939 static void store_pid(const char *path)
 940 {
 941         FILE *f = fopen(path, "w");
 942         if (!f)
 943                 die_errno("cannot open pid file '%s'", path);
 944         if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
 945                 die_errno("failed to write pid file '%s'", path);
 946 }
 947
 948 static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
 949 {
 950         int socknum, *socklist;
 951
 952         socknum = socksetup(listen_addr, listen_port, &socklist);
 953         if (socknum == 0)
 954                 die("unable to allocate any listen sockets on host %s port %u",
 955                     listen_addr, listen_port);
 956
 957         if (pass && gid &&
 958             (initgroups(pass->pw_name, gid) || setgid (gid) ||
 959              setuid(pass->pw_uid)))
 960                 die("cannot drop privileges");
 961
 962         return service_loop(socknum, socklist);
 963 }
 964
 965 int main(int argc, char **argv)
 966 {
 967         int listen_port = 0;
 968         char *listen_addr = NULL;
 969         int inetd_mode = 0;
 970         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
 971         int detach = 0;
 972         struct passwd *pass = NULL;
 973         struct group *group;
 974         gid_t gid = 0;
 975         int i;
 976
 977         git_extract_argv0_path(argv[0]);
 978
 979         for (i = 1; i < argc; i++) {
 980                 char *arg = argv[i];
 981
 982                 if (!prefixcmp(arg, "--listen=")) {
 983                         listen_addr = xstrdup_tolower(arg + 9);
 984                         continue;
 985                 }
 986                 if (!prefixcmp(arg, "--port=")) {
 987                         char *end;
 988                         unsigned long n;
 989                         n = strtoul(arg+7, &end, 0);
 990                         if (arg[7] && !*end) {
 991                                 listen_port = n;
 992                                 continue;
 993                         }
 994                 }
 995                 if (!strcmp(arg, "--inetd")) {
 996                         inetd_mode = 1;
 997                         log_syslog = 1;
 998                         continue;
 999                 }
1000                 if (!strcmp(arg, "--verbose")) {
1001                         verbose = 1;
1002                         continue;
1003                 }
1004                 if (!strcmp(arg, "--syslog")) {
1005                         log_syslog = 1;
1006                         continue;
1007                 }
1008                 if (!strcmp(arg, "--export-all")) {
1009                         export_all_trees = 1;
1010                         continue;
1011                 }
1012                 if (!prefixcmp(arg, "--timeout=")) {
1013                         timeout = atoi(arg+10);
1014                         continue;
1015                 }
1016                 if (!prefixcmp(arg, "--init-timeout=")) {
1017                         init_timeout = atoi(arg+15);
1018                         continue;
1019                 }
1020                 if (!prefixcmp(arg, "--max-connections=")) {
1021                         max_connections = atoi(arg+18);
1022                         if (max_connections < 0)
1023                                 max_connections = 0;            /* unlimited */
1024                         continue;
1025                 }
1026                 if (!strcmp(arg, "--strict-paths")) {
1027                         strict_paths = 1;
1028                         continue;
1029                 }
1030                 if (!prefixcmp(arg, "--base-path=")) {
1031                         base_path = arg+12;
1032                         continue;
1033                 }
1034                 if (!strcmp(arg, "--base-path-relaxed")) {
1035                         base_path_relaxed = 1;
1036                         continue;
1037                 }
1038                 if (!prefixcmp(arg, "--interpolated-path=")) {
1039                         interpolated_path = arg+20;
1040                         continue;
1041                 }
1042                 if (!strcmp(arg, "--reuseaddr")) {
1043                         reuseaddr = 1;
1044                         continue;
1045                 }
1046                 if (!strcmp(arg, "--user-path")) {
1047                         user_path = "";
1048                         continue;
1049                 }
1050                 if (!prefixcmp(arg, "--user-path=")) {
1051                         user_path = arg + 12;
1052                         continue;
1053                 }
1054                 if (!prefixcmp(arg, "--pid-file=")) {
1055                         pid_file = arg + 11;
1056                         continue;
1057                 }
1058                 if (!strcmp(arg, "--detach")) {
1059                         detach = 1;
1060                         log_syslog = 1;
1061                         continue;
1062                 }
1063                 if (!prefixcmp(arg, "--user=")) {
1064                         user_name = arg + 7;
1065                         continue;
1066                 }
1067                 if (!prefixcmp(arg, "--group=")) {
1068                         group_name = arg + 8;
1069                         continue;
1070                 }
1071                 if (!prefixcmp(arg, "--enable=")) {
1072                         enable_service(arg + 9, 1);
1073                         continue;
1074                 }
1075                 if (!prefixcmp(arg, "--disable=")) {
1076                         enable_service(arg + 10, 0);
1077                         continue;
1078                 }
1079                 if (!prefixcmp(arg, "--allow-override=")) {
1080                         make_service_overridable(arg + 17, 1);
1081                         continue;
1082                 }
1083                 if (!prefixcmp(arg, "--forbid-override=")) {
1084                         make_service_overridable(arg + 18, 0);
1085                         continue;
1086                 }
1087                 if (!strcmp(arg, "--")) {
1088                         ok_paths = &argv[i+1];
1089                         break;
1090                 } else if (arg[0] != '-') {
1091                         ok_paths = &argv[i];
1092                         break;
1093                 }
1094
1095                 usage(daemon_usage);
1096         }
1097
1098         if (log_syslog) {
1099                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1100                 set_die_routine(daemon_die);
1101         } else
1102                 /* avoid splitting a message in the middle */
1103                 setvbuf(stderr, NULL, _IOLBF, 0);
1104
1105         if (inetd_mode && (group_name || user_name))
1106                 die("--user and --group are incompatible with --inetd");
1107
1108         if (inetd_mode && (listen_port || listen_addr))
1109                 die("--listen= and --port= are incompatible with --inetd");
1110         else if (listen_port == 0)
1111                 listen_port = DEFAULT_GIT_PORT;
1112
1113         if (group_name && !user_name)
1114                 die("--group supplied without --user");
1115
1116         if (user_name) {
1117                 pass = getpwnam(user_name);
1118                 if (!pass)
1119                         die("user not found - %s", user_name);
1120
1121                 if (!group_name)
1122                         gid = pass->pw_gid;
1123                 else {
1124                         group = getgrnam(group_name);
1125                         if (!group)
1126                                 die("group not found - %s", group_name);
1127
1128                         gid = group->gr_gid;
1129                 }
1130         }
1131
1132         if (strict_paths && (!ok_paths || !*ok_paths))
1133                 die("option --strict-paths requires a whitelist");
1134
1135         if (base_path && !is_directory(base_path))
1136                 die("base-path '%s' does not exist or is not a directory",
1137                     base_path);
1138
1139         if (inetd_mode) {
1140                 struct sockaddr_storage ss;
1141                 struct sockaddr *peer = (struct sockaddr *)&ss;
1142                 socklen_t slen = sizeof(ss);
1143
1144                 if (!freopen("/dev/null", "w", stderr))
1145                         die_errno("failed to redirect stderr to /dev/null");
1146
1147                 if (getpeername(0, peer, &slen))
1148                         peer = NULL;
1149
1150                 return execute(peer);
1151         }
1152
1153         if (detach) {
1154                 daemonize();
1155                 loginfo("Ready to rumble");
1156         }
1157         else
1158                 sanitize_stdfds();
1159
1160         if (pid_file)
1161                 store_pid(pid_file);
1162
1163         return serve(listen_addr, listen_port, pass, gid);
1164 }