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[6];
 145
 146                 dict[0].placeholder = "H"; dict[0].value = hostname;
 147                 dict[1].placeholder = "CH"; dict[1].value = canon_hostname;
 148                 dict[2].placeholder = "IP"; dict[2].value = ip_address;
 149                 dict[3].placeholder = "P"; dict[3].value = tcp_port;
 150                 dict[4].placeholder = "D"; dict[4].value = directory;
 151                 dict[5].placeholder = NULL; dict[5].value = NULL;
 152                 if (*dir != '/') {
 153                         /* Allow only absolute */
 154                         logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 155                         return NULL;
 156                 }
 157
 158                 strbuf_expand(&expanded_path, interpolated_path,
 159                                 strbuf_expand_dict_cb, &dict);
 160                 strlcpy(interp_path, expanded_path.buf, PATH_MAX);
 161                 strbuf_release(&expanded_path);
 162                 loginfo("Interpolated dir '%s'", interp_path);
 163
 164                 dir = interp_path;
 165         }
 166         else if (base_path) {
 167                 if (*dir != '/') {
 168                         /* Allow only absolute */
 169                         logerror("'%s': Non-absolute path denied (base-path active)", dir);
 170                         return NULL;
 171                 }
 172                 snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
 173                 dir = rpath;
 174         }
 175
 176         path = enter_repo(dir, strict_paths);
 177         if (!path && base_path && base_path_relaxed) {
 178                 /*
 179                  * if we fail and base_path_relaxed is enabled, try without
 180                  * prefixing the base path
 181                  */
 182                 dir = directory;
 183                 path = enter_repo(dir, strict_paths);
 184         }
 185
 186         if (!path) {
 187                 logerror("'%s' does not appear to be a git repository", dir);
 188                 return NULL;
 189         }
 190
 191         if ( ok_paths && *ok_paths ) {
 192                 char **pp;
 193                 int pathlen = strlen(path);
 194
 195                 /* The validation is done on the paths after enter_repo
 196                  * appends optional {.git,.git/.git} and friends, but
 197                  * it does not use getcwd().  So if your /pub is
 198                  * a symlink to /mnt/pub, you can whitelist /pub and
 199                  * do not have to say /mnt/pub.
 200                  * Do not say /pub/.
 201                  */
 202                 for ( pp = ok_paths ; *pp ; pp++ ) {
 203                         int len = strlen(*pp);
 204                         if (len <= pathlen &&
 205                             !memcmp(*pp, path, len) &&
 206                             (path[len] == '\0' ||
 207                              (!strict_paths && path[len] == '/')))
 208                                 return path;
 209                 }
 210         }
 211         else {
 212                 /* be backwards compatible */
 213                 if (!strict_paths)
 214                         return path;
 215         }
 216
 217         logerror("'%s': not in whitelist", path);
 218         return NULL;            /* Fallthrough. Deny by default */
 219 }
 220
 221 typedef int (*daemon_service_fn)(void);
 222 struct daemon_service {
 223         const char *name;
 224         const char *config_name;
 225         daemon_service_fn fn;
 226         int enabled;
 227         int overridable;
 228 };
 229
 230 static struct daemon_service *service_looking_at;
 231 static int service_enabled;
 232
 233 static int git_daemon_config(const char *var, const char *value, void *cb)
 234 {
 235         if (!prefixcmp(var, "daemon.") &&
 236             !strcmp(var + 7, service_looking_at->config_name)) {
 237                 service_enabled = git_config_bool(var, value);
 238                 return 0;
 239         }
 240
 241         /* we are not interested in parsing any other configuration here */
 242         return 0;
 243 }
 244
 245 static int run_service(char *dir, struct daemon_service *service)
 246 {
 247         const char *path;
 248         int enabled = service->enabled;
 249
 250         loginfo("Request %s for '%s'", service->name, dir);
 251
 252         if (!enabled && !service->overridable) {
 253                 logerror("'%s': service not enabled.", service->name);
 254                 errno = EACCES;
 255                 return -1;
 256         }
 257
 258         if (!(path = path_ok(dir)))
 259                 return -1;
 260
 261         /*
 262          * Security on the cheap.
 263          *
 264          * We want a readable HEAD, usable "objects" directory, and
 265          * a "git-daemon-export-ok" flag that says that the other side
 266          * is ok with us doing this.
 267          *
 268          * path_ok() uses enter_repo() and does whitelist checking.
 269          * We only need to make sure the repository is exported.
 270          */
 271
 272         if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 273                 logerror("'%s': repository not exported.", path);
 274                 errno = EACCES;
 275                 return -1;
 276         }
 277
 278         if (service->overridable) {
 279                 service_looking_at = service;
 280                 service_enabled = -1;
 281                 git_config(git_daemon_config, NULL);
 282                 if (0 <= service_enabled)
 283                         enabled = service_enabled;
 284         }
 285         if (!enabled) {
 286                 logerror("'%s': service not enabled for '%s'",
 287                          service->name, path);
 288                 errno = EACCES;
 289                 return -1;
 290         }
 291
 292         /*
 293          * We'll ignore SIGTERM from now on, we have a
 294          * good client.
 295          */
 296         signal(SIGTERM, SIG_IGN);
 297
 298         return service->fn();
 299 }
 300
 301 static void copy_to_log(int fd)
 302 {
 303         struct strbuf line = STRBUF_INIT;
 304         FILE *fp;
 305
 306         fp = fdopen(fd, "r");
 307         if (fp == NULL) {
 308                 logerror("fdopen of error channel failed");
 309                 close(fd);
 310                 return;
 311         }
 312
 313         while (strbuf_getline(&line, fp, '\n') != EOF) {
 314                 logerror("%s", line.buf);
 315                 strbuf_setlen(&line, 0);
 316         }
 317
 318         strbuf_release(&line);
 319         fclose(fp);
 320 }
 321
 322 static int run_service_command(const char **argv)
 323 {
 324         struct child_process cld;
 325
 326         memset(&cld, 0, sizeof(cld));
 327         cld.argv = argv;
 328         cld.git_cmd = 1;
 329         cld.err = -1;
 330         if (start_command(&cld))
 331                 return -1;
 332
 333         close(0);
 334         close(1);
 335
 336         copy_to_log(cld.err);
 337
 338         return finish_command(&cld);
 339 }
 340
 341 static int upload_pack(void)
 342 {
 343         /* Timeout as string */
 344         char timeout_buf[64];
 345         const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
 346
 347         argv[2] = timeout_buf;
 348
 349         snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 350         return run_service_command(argv);
 351 }
 352
 353 static int upload_archive(void)
 354 {
 355         static const char *argv[] = { "upload-archive", ".", NULL };
 356         return run_service_command(argv);
 357 }
 358
 359 static int receive_pack(void)
 360 {
 361         static const char *argv[] = { "receive-pack", ".", NULL };
 362         return run_service_command(argv);
 363 }
 364
 365 static struct daemon_service daemon_service[] = {
 366         { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 367         { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 368         { "receive-pack", "receivepack", receive_pack, 0, 1 },
 369 };
 370
 371 static void enable_service(const char *name, int ena)
 372 {
 373         int i;
 374         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 375                 if (!strcmp(daemon_service[i].name, name)) {
 376                         daemon_service[i].enabled = ena;
 377                         return;
 378                 }
 379         }
 380         die("No such service %s", name);
 381 }
 382
 383 static void make_service_overridable(const char *name, int ena)
 384 {
 385         int i;
 386         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 387                 if (!strcmp(daemon_service[i].name, name)) {
 388                         daemon_service[i].overridable = ena;
 389                         return;
 390                 }
 391         }
 392         die("No such service %s", name);
 393 }
 394
 395 static char *xstrdup_tolower(const char *str)
 396 {
 397         char *p, *dup = xstrdup(str);
 398         for (p = dup; *p; p++)
 399                 *p = tolower(*p);
 400         return dup;
 401 }
 402
 403 static void parse_host_and_port(char *hostport, char **host,
 404         char **port)
 405 {
 406         if (*hostport == '[') {
 407                 char *end;
 408
 409                 end = strchr(hostport, ']');
 410                 if (!end)
 411                         die("Invalid request ('[' without ']')");
 412                 *end = '\0';
 413                 *host = hostport + 1;
 414                 if (!end[1])
 415                         *port = NULL;
 416                 else if (end[1] == ':')
 417                         *port = end + 2;
 418                 else
 419                         die("Garbage after end of host part");
 420         } else {
 421                 *host = hostport;
 422                 *port = strrchr(hostport, ':');
 423                 if (*port) {
 424                         **port = '\0';
 425                         ++*port;
 426                 }
 427         }
 428 }
 429
 430 /*
 431  * Read the host as supplied by the client connection.
 432  */
 433 static void parse_host_arg(char *extra_args, int buflen)
 434 {
 435         char *val;
 436         int vallen;
 437         char *end = extra_args + buflen;
 438
 439         if (extra_args < end && *extra_args) {
 440                 saw_extended_args = 1;
 441                 if (strncasecmp("host=", extra_args, 5) == 0) {
 442                         val = extra_args + 5;
 443                         vallen = strlen(val) + 1;
 444                         if (*val) {
 445                                 /* Split <host>:<port> at colon. */
 446                                 char *host;
 447                                 char *port;
 448                                 parse_host_and_port(val, &host, &port);
 449                                 if (port) {
 450                                         free(tcp_port);
 451                                         tcp_port = xstrdup(port);
 452                                 }
 453                                 free(hostname);
 454                                 hostname = xstrdup_tolower(host);
 455                         }
 456
 457                         /* On to the next one */
 458                         extra_args = val + vallen;
 459                 }
 460                 if (extra_args < end && *extra_args)
 461                         die("Invalid request");
 462         }
 463
 464         /*
 465          * Locate canonical hostname and its IP address.
 466          */
 467         if (hostname) {
 468 #ifndef NO_IPV6
 469                 struct addrinfo hints;
 470                 struct addrinfo *ai;
 471                 int gai;
 472                 static char addrbuf[HOST_NAME_MAX + 1];
 473
 474                 memset(&hints, 0, sizeof(hints));
 475                 hints.ai_flags = AI_CANONNAME;
 476
 477                 gai = getaddrinfo(hostname, NULL, &hints, &ai);
 478                 if (!gai) {
 479                         struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 480
 481                         inet_ntop(AF_INET, &sin_addr->sin_addr,
 482                                   addrbuf, sizeof(addrbuf));
 483                         free(ip_address);
 484                         ip_address = xstrdup(addrbuf);
 485
 486                         free(canon_hostname);
 487                         canon_hostname = xstrdup(ai->ai_canonname ?
 488                                                  ai->ai_canonname : ip_address);
 489
 490                         freeaddrinfo(ai);
 491                 }
 492 #else
 493                 struct hostent *hent;
 494                 struct sockaddr_in sa;
 495                 char **ap;
 496                 static char addrbuf[HOST_NAME_MAX + 1];
 497
 498                 hent = gethostbyname(hostname);
 499
 500                 ap = hent->h_addr_list;
 501                 memset(&sa, 0, sizeof sa);
 502                 sa.sin_family = hent->h_addrtype;
 503                 sa.sin_port = htons(0);
 504                 memcpy(&sa.sin_addr, *ap, hent->h_length);
 505
 506                 inet_ntop(hent->h_addrtype, &sa.sin_addr,
 507                           addrbuf, sizeof(addrbuf));
 508
 509                 free(canon_hostname);
 510                 canon_hostname = xstrdup(hent->h_name);
 511                 free(ip_address);
 512                 ip_address = xstrdup(addrbuf);
 513 #endif
 514         }
 515 }
 516
 517
 518 static int execute(struct sockaddr *addr)
 519 {
 520         static char line[1000];
 521         int pktlen, len, i;
 522
 523         if (addr) {
 524                 char addrbuf[256] = "";
 525                 int port = -1;
 526
 527                 if (addr->sa_family == AF_INET) {
 528                         struct sockaddr_in *sin_addr = (void *) addr;
 529                         inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
 530                         port = ntohs(sin_addr->sin_port);
 531 #ifndef NO_IPV6
 532                 } else if (addr && addr->sa_family == AF_INET6) {
 533                         struct sockaddr_in6 *sin6_addr = (void *) addr;
 534
 535                         char *buf = addrbuf;
 536                         *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 537                         inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
 538                         strcat(buf, "]");
 539
 540                         port = ntohs(sin6_addr->sin6_port);
 541 #endif
 542                 }
 543                 loginfo("Connection from %s:%d", addrbuf, port);
 544                 setenv("REMOTE_ADDR", addrbuf, 1);
 545         }
 546         else {
 547                 unsetenv("REMOTE_ADDR");
 548         }
 549
 550         alarm(init_timeout ? init_timeout : timeout);
 551         pktlen = packet_read_line(0, line, sizeof(line));
 552         alarm(0);
 553
 554         len = strlen(line);
 555         if (pktlen != len)
 556                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
 557                         (int) pktlen - len,
 558                         (int) pktlen - len, line + len + 1);
 559         if (len && line[len-1] == '\n') {
 560                 line[--len] = 0;
 561                 pktlen--;
 562         }
 563
 564         free(hostname);
 565         free(canon_hostname);
 566         free(ip_address);
 567         free(tcp_port);
 568         hostname = canon_hostname = ip_address = tcp_port = NULL;
 569
 570         if (len != pktlen)
 571                 parse_host_arg(line + len + 1, pktlen - len - 1);
 572
 573         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 574                 struct daemon_service *s = &(daemon_service[i]);
 575                 int namelen = strlen(s->name);
 576                 if (!prefixcmp(line, "git-") &&
 577                     !strncmp(s->name, line + 4, namelen) &&
 578                     line[namelen + 4] == ' ') {
 579                         /*
 580                          * Note: The directory here is probably context sensitive,
 581                          * and might depend on the actual service being performed.
 582                          */
 583                         return run_service(line + namelen + 5, s);
 584                 }
 585         }
 586
 587         logerror("Protocol error: '%s'", line);
 588         return -1;
 589 }
 590
 591 static int addrcmp(const struct sockaddr_storage *s1,
 592     const struct sockaddr_storage *s2)
 593 {
 594         const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 595         const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 596
 597         if (sa1->sa_family != sa2->sa_family)
 598                 return sa1->sa_family - sa2->sa_family;
 599         if (sa1->sa_family == AF_INET)
 600                 return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 601                     &((struct sockaddr_in *)s2)->sin_addr,
 602                     sizeof(struct in_addr));
 603 #ifndef NO_IPV6
 604         if (sa1->sa_family == AF_INET6)
 605                 return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 606                     &((struct sockaddr_in6 *)s2)->sin6_addr,
 607                     sizeof(struct in6_addr));
 608 #endif
 609         return 0;
 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         newborn = xcalloc(1, sizeof(*newborn));
 627         live_children++;
 628         newborn->pid = pid;
 629         memcpy(&newborn->address, addr, addrlen);
 630         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 631                 if (!addrcmp(&(*cradle)->address, &newborn->address))
 632                         break;
 633         newborn->next = *cradle;
 634         *cradle = newborn;
 635 }
 636
 637 static void remove_child(pid_t pid)
 638 {
 639         struct child **cradle, *blanket;
 640
 641         for (cradle = &firstborn; (blanket = *cradle); cradle = &blanket->next)
 642                 if (blanket->pid == pid) {
 643                         *cradle = blanket->next;
 644                         live_children--;
 645                         free(blanket);
 646                         break;
 647                 }
 648 }
 649
 650 /*
 651  * This gets called if the number of connections grows
 652  * past "max_connections".
 653  *
 654  * We kill the newest connection from a duplicate IP.
 655  */
 656 static void kill_some_child(void)
 657 {
 658         const struct child *blanket, *next;
 659
 660         if (!(blanket = firstborn))
 661                 return;
 662
 663         for (; (next = blanket->next); blanket = next)
 664                 if (!addrcmp(&blanket->address, &next->address)) {
 665                         kill(blanket->pid, SIGTERM);
 666                         break;
 667                 }
 668 }
 669
 670 static void check_dead_children(void)
 671 {
 672         int status;
 673         pid_t pid;
 674
 675         while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
 676                 const char *dead = "";
 677                 remove_child(pid);
 678                 if (!WIFEXITED(status) || (WEXITSTATUS(status) > 0))
 679                         dead = " (with error)";
 680                 loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 681         }
 682 }
 683
 684 static void handle(int incoming, struct sockaddr *addr, int addrlen)
 685 {
 686         pid_t pid;
 687
 688         if (max_connections && live_children >= max_connections) {
 689                 kill_some_child();
 690                 sleep(1);  /* give it some time to die */
 691                 check_dead_children();
 692                 if (live_children >= max_connections) {
 693                         close(incoming);
 694                         logerror("Too many children, dropping connection");
 695                         return;
 696                 }
 697         }
 698
 699         if ((pid = fork())) {
 700                 close(incoming);
 701                 if (pid < 0) {
 702                         logerror("Couldn't fork %s", strerror(errno));
 703                         return;
 704                 }
 705
 706                 add_child(pid, addr, addrlen);
 707                 return;
 708         }
 709
 710         dup2(incoming, 0);
 711         dup2(incoming, 1);
 712         close(incoming);
 713
 714         exit(execute(addr));
 715 }
 716
 717 static void child_handler(int signo)
 718 {
 719         /*
 720          * Otherwise empty handler because systemcalls will get interrupted
 721          * upon signal receipt
 722          * SysV needs the handler to be rearmed
 723          */
 724         signal(SIGCHLD, child_handler);
 725 }
 726
 727 static int set_reuse_addr(int sockfd)
 728 {
 729         int on = 1;
 730
 731         if (!reuseaddr)
 732                 return 0;
 733         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 734                           &on, sizeof(on));
 735 }
 736
 737 #ifndef NO_IPV6
 738
 739 static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 740 {
 741         int socknum = 0, *socklist = NULL;
 742         int maxfd = -1;
 743         char pbuf[NI_MAXSERV];
 744         struct addrinfo hints, *ai0, *ai;
 745         int gai;
 746         long flags;
 747
 748         sprintf(pbuf, "%d", listen_port);
 749         memset(&hints, 0, sizeof(hints));
 750         hints.ai_family = AF_UNSPEC;
 751         hints.ai_socktype = SOCK_STREAM;
 752         hints.ai_protocol = IPPROTO_TCP;
 753         hints.ai_flags = AI_PASSIVE;
 754
 755         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 756         if (gai)
 757                 die("getaddrinfo() failed: %s", gai_strerror(gai));
 758
 759         for (ai = ai0; ai; ai = ai->ai_next) {
 760                 int sockfd;
 761
 762                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 763                 if (sockfd < 0)
 764                         continue;
 765                 if (sockfd >= FD_SETSIZE) {
 766                         logerror("Socket descriptor too large");
 767                         close(sockfd);
 768                         continue;
 769                 }
 770
 771 #ifdef IPV6_V6ONLY
 772                 if (ai->ai_family == AF_INET6) {
 773                         int on = 1;
 774                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 775                                    &on, sizeof(on));
 776                         /* Note: error is not fatal */
 777                 }
 778 #endif
 779
 780                 if (set_reuse_addr(sockfd)) {
 781                         close(sockfd);
 782                         continue;
 783                 }
 784
 785                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 786                         close(sockfd);
 787                         continue;       /* not fatal */
 788                 }
 789                 if (listen(sockfd, 5) < 0) {
 790                         close(sockfd);
 791                         continue;       /* not fatal */
 792                 }
 793
 794                 flags = fcntl(sockfd, F_GETFD, 0);
 795                 if (flags >= 0)
 796                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 797
 798                 socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
 799                 socklist[socknum++] = sockfd;
 800
 801                 if (maxfd < sockfd)
 802                         maxfd = sockfd;
 803         }
 804
 805         freeaddrinfo(ai0);
 806
 807         *socklist_p = socklist;
 808         return socknum;
 809 }
 810
 811 #else /* NO_IPV6 */
 812
 813 static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 814 {
 815         struct sockaddr_in sin;
 816         int sockfd;
 817         long flags;
 818
 819         memset(&sin, 0, sizeof sin);
 820         sin.sin_family = AF_INET;
 821         sin.sin_port = htons(listen_port);
 822
 823         if (listen_addr) {
 824                 /* Well, host better be an IP address here. */
 825                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 826                         return 0;
 827         } else {
 828                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
 829         }
 830
 831         sockfd = socket(AF_INET, SOCK_STREAM, 0);
 832         if (sockfd < 0)
 833                 return 0;
 834
 835         if (set_reuse_addr(sockfd)) {
 836                 close(sockfd);
 837                 return 0;
 838         }
 839
 840         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 841                 close(sockfd);
 842                 return 0;
 843         }
 844
 845         if (listen(sockfd, 5) < 0) {
 846                 close(sockfd);
 847                 return 0;
 848         }
 849
 850         flags = fcntl(sockfd, F_GETFD, 0);
 851         if (flags >= 0)
 852                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 853
 854         *socklist_p = xmalloc(sizeof(int));
 855         **socklist_p = sockfd;
 856         return 1;
 857 }
 858
 859 #endif
 860
 861 static int service_loop(int socknum, int *socklist)
 862 {
 863         struct pollfd *pfd;
 864         int i;
 865
 866         pfd = xcalloc(socknum, sizeof(struct pollfd));
 867
 868         for (i = 0; i < socknum; i++) {
 869                 pfd[i].fd = socklist[i];
 870                 pfd[i].events = POLLIN;
 871         }
 872
 873         signal(SIGCHLD, child_handler);
 874
 875         for (;;) {
 876                 int i;
 877
 878                 check_dead_children();
 879
 880                 if (poll(pfd, socknum, -1) < 0) {
 881                         if (errno != EINTR) {
 882                                 logerror("Poll failed, resuming: %s",
 883                                       strerror(errno));
 884                                 sleep(1);
 885                         }
 886                         continue;
 887                 }
 888
 889                 for (i = 0; i < socknum; i++) {
 890                         if (pfd[i].revents & POLLIN) {
 891                                 struct sockaddr_storage ss;
 892                                 unsigned int sslen = sizeof(ss);
 893                                 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
 894                                 if (incoming < 0) {
 895                                         switch (errno) {
 896                                         case EAGAIN:
 897                                         case EINTR:
 898                                         case ECONNABORTED:
 899                                                 continue;
 900                                         default:
 901                                                 die_errno("accept returned");
 902                                         }
 903                                 }
 904                                 handle(incoming, (struct sockaddr *)&ss, sslen);
 905                         }
 906                 }
 907         }
 908 }
 909
 910 /* if any standard file descriptor is missing open it to /dev/null */
 911 static void sanitize_stdfds(void)
 912 {
 913         int fd = open("/dev/null", O_RDWR, 0);
 914         while (fd != -1 && fd < 2)
 915                 fd = dup(fd);
 916         if (fd == -1)
 917                 die_errno("open /dev/null or dup failed");
 918         if (fd > 2)
 919                 close(fd);
 920 }
 921
 922 static void daemonize(void)
 923 {
 924         switch (fork()) {
 925                 case 0:
 926                         break;
 927                 case -1:
 928                         die_errno("fork failed");
 929                 default:
 930                         exit(0);
 931         }
 932         if (setsid() == -1)
 933                 die_errno("setsid failed");
 934         close(0);
 935         close(1);
 936         close(2);
 937         sanitize_stdfds();
 938 }
 939
 940 static void store_pid(const char *path)
 941 {
 942         FILE *f = fopen(path, "w");
 943         if (!f)
 944                 die_errno("cannot open pid file '%s'", path);
 945         if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
 946                 die_errno("failed to write pid file '%s'", path);
 947 }
 948
 949 static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
 950 {
 951         int socknum, *socklist;
 952
 953         socknum = socksetup(listen_addr, listen_port, &socklist);
 954         if (socknum == 0)
 955                 die("unable to allocate any listen sockets on host %s port %u",
 956                     listen_addr, listen_port);
 957
 958         if (pass && gid &&
 959             (initgroups(pass->pw_name, gid) || setgid (gid) ||
 960              setuid(pass->pw_uid)))
 961                 die("cannot drop privileges");
 962
 963         return service_loop(socknum, socklist);
 964 }
 965
 966 int main(int argc, char **argv)
 967 {
 968         int listen_port = 0;
 969         char *listen_addr = NULL;
 970         int inetd_mode = 0;
 971         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
 972         int detach = 0;
 973         struct passwd *pass = NULL;
 974         struct group *group;
 975         gid_t gid = 0;
 976         int i;
 977
 978         git_extract_argv0_path(argv[0]);
 979
 980         for (i = 1; i < argc; i++) {
 981                 char *arg = argv[i];
 982
 983                 if (!prefixcmp(arg, "--listen=")) {
 984                         listen_addr = xstrdup_tolower(arg + 9);
 985                         continue;
 986                 }
 987                 if (!prefixcmp(arg, "--port=")) {
 988                         char *end;
 989                         unsigned long n;
 990                         n = strtoul(arg+7, &end, 0);
 991                         if (arg[7] && !*end) {
 992                                 listen_port = n;
 993                                 continue;
 994                         }
 995                 }
 996                 if (!strcmp(arg, "--inetd")) {
 997                         inetd_mode = 1;
 998                         log_syslog = 1;
 999                         continue;
1000                 }
1001                 if (!strcmp(arg, "--verbose")) {
1002                         verbose = 1;
1003                         continue;
1004                 }
1005                 if (!strcmp(arg, "--syslog")) {
1006                         log_syslog = 1;
1007                         continue;
1008                 }
1009                 if (!strcmp(arg, "--export-all")) {
1010                         export_all_trees = 1;
1011                         continue;
1012                 }
1013                 if (!prefixcmp(arg, "--timeout=")) {
1014                         timeout = atoi(arg+10);
1015                         continue;
1016                 }
1017                 if (!prefixcmp(arg, "--init-timeout=")) {
1018                         init_timeout = atoi(arg+15);
1019                         continue;
1020                 }
1021                 if (!prefixcmp(arg, "--max-connections=")) {
1022                         max_connections = atoi(arg+18);
1023                         if (max_connections < 0)
1024                                 max_connections = 0;            /* unlimited */
1025                         continue;
1026                 }
1027                 if (!strcmp(arg, "--strict-paths")) {
1028                         strict_paths = 1;
1029                         continue;
1030                 }
1031                 if (!prefixcmp(arg, "--base-path=")) {
1032                         base_path = arg+12;
1033                         continue;
1034                 }
1035                 if (!strcmp(arg, "--base-path-relaxed")) {
1036                         base_path_relaxed = 1;
1037                         continue;
1038                 }
1039                 if (!prefixcmp(arg, "--interpolated-path=")) {
1040                         interpolated_path = arg+20;
1041                         continue;
1042                 }
1043                 if (!strcmp(arg, "--reuseaddr")) {
1044                         reuseaddr = 1;
1045                         continue;
1046                 }
1047                 if (!strcmp(arg, "--user-path")) {
1048                         user_path = "";
1049                         continue;
1050                 }
1051                 if (!prefixcmp(arg, "--user-path=")) {
1052                         user_path = arg + 12;
1053                         continue;
1054                 }
1055                 if (!prefixcmp(arg, "--pid-file=")) {
1056                         pid_file = arg + 11;
1057                         continue;
1058                 }
1059                 if (!strcmp(arg, "--detach")) {
1060                         detach = 1;
1061                         log_syslog = 1;
1062                         continue;
1063                 }
1064                 if (!prefixcmp(arg, "--user=")) {
1065                         user_name = arg + 7;
1066                         continue;
1067                 }
1068                 if (!prefixcmp(arg, "--group=")) {
1069                         group_name = arg + 8;
1070                         continue;
1071                 }
1072                 if (!prefixcmp(arg, "--enable=")) {
1073                         enable_service(arg + 9, 1);
1074                         continue;
1075                 }
1076                 if (!prefixcmp(arg, "--disable=")) {
1077                         enable_service(arg + 10, 0);
1078                         continue;
1079                 }
1080                 if (!prefixcmp(arg, "--allow-override=")) {
1081                         make_service_overridable(arg + 17, 1);
1082                         continue;
1083                 }
1084                 if (!prefixcmp(arg, "--forbid-override=")) {
1085                         make_service_overridable(arg + 18, 0);
1086                         continue;
1087                 }
1088                 if (!strcmp(arg, "--")) {
1089                         ok_paths = &argv[i+1];
1090                         break;
1091                 } else if (arg[0] != '-') {
1092                         ok_paths = &argv[i];
1093                         break;
1094                 }
1095
1096                 usage(daemon_usage);
1097         }
1098
1099         if (log_syslog) {
1100                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1101                 set_die_routine(daemon_die);
1102         } else
1103                 /* avoid splitting a message in the middle */
1104                 setvbuf(stderr, NULL, _IOLBF, 0);
1105
1106         if (inetd_mode && (group_name || user_name))
1107                 die("--user and --group are incompatible with --inetd");
1108
1109         if (inetd_mode && (listen_port || listen_addr))
1110                 die("--listen= and --port= are incompatible with --inetd");
1111         else if (listen_port == 0)
1112                 listen_port = DEFAULT_GIT_PORT;
1113
1114         if (group_name && !user_name)
1115                 die("--group supplied without --user");
1116
1117         if (user_name) {
1118                 pass = getpwnam(user_name);
1119                 if (!pass)
1120                         die("user not found - %s", user_name);
1121
1122                 if (!group_name)
1123                         gid = pass->pw_gid;
1124                 else {
1125                         group = getgrnam(group_name);
1126                         if (!group)
1127                                 die("group not found - %s", group_name);
1128
1129                         gid = group->gr_gid;
1130                 }
1131         }
1132
1133         if (strict_paths && (!ok_paths || !*ok_paths))
1134                 die("option --strict-paths requires a whitelist");
1135
1136         if (base_path && !is_directory(base_path))
1137                 die("base-path '%s' does not exist or is not a directory",
1138                     base_path);
1139
1140         if (inetd_mode) {
1141                 struct sockaddr_storage ss;
1142                 struct sockaddr *peer = (struct sockaddr *)&ss;
1143                 socklen_t slen = sizeof(ss);
1144
1145                 if (!freopen("/dev/null", "w", stderr))
1146                         die_errno("failed to redirect stderr to /dev/null");
1147
1148                 if (getpeername(0, peer, &slen))
1149                         peer = NULL;
1150
1151                 return execute(peer);
1152         }
1153
1154         if (detach) {
1155                 daemonize();
1156                 loginfo("Ready to rumble");
1157         }
1158         else
1159                 sanitize_stdfds();
1160
1161         if (pid_file)
1162                 store_pid(pid_file);
1163
1164         return serve(listen_addr, listen_port, pass, gid);
1165 }