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 static void logerror(const char *err, ...)
  81 {
  82         va_list params;
  83         va_start(params, err);
  84         logreport(LOG_ERR, err, params);
  85         va_end(params);
  86 }
  87
  88 static void loginfo(const char *err, ...)
  89 {
  90         va_list params;
  91         if (!verbose)
  92                 return;
  93         va_start(params, err);
  94         logreport(LOG_INFO, err, params);
  95         va_end(params);
  96 }
  97
  98 static void NORETURN daemon_die(const char *err, va_list params)
  99 {
 100         logreport(LOG_ERR, err, params);
 101         exit(1);
 102 }
 103
 104 static char *path_ok(char *directory)
 105 {
 106         static char rpath[PATH_MAX];
 107         static char interp_path[PATH_MAX];
 108         char *path;
 109         char *dir;
 110
 111         dir = directory;
 112
 113         if (daemon_avoid_alias(dir)) {
 114                 logerror("'%s': aliased", dir);
 115                 return NULL;
 116         }
 117
 118         if (*dir == '~') {
 119                 if (!user_path) {
 120                         logerror("'%s': User-path not allowed", dir);
 121                         return NULL;
 122                 }
 123                 if (*user_path) {
 124                         /* Got either "~alice" or "~alice/foo";
 125                          * rewrite them to "~alice/%s" or
 126                          * "~alice/%s/foo".
 127                          */
 128                         int namlen, restlen = strlen(dir);
 129                         char *slash = strchr(dir, '/');
 130                         if (!slash)
 131                                 slash = dir + restlen;
 132                         namlen = slash - dir;
 133                         restlen -= namlen;
 134                         loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
 135                         snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
 136                                  namlen, dir, user_path, restlen, slash);
 137                         dir = rpath;
 138                 }
 139         }
 140         else if (interpolated_path && saw_extended_args) {
 141                 struct strbuf expanded_path = STRBUF_INIT;
 142                 struct strbuf_expand_dict_entry dict[] = {
 143                         { "H", hostname },
 144                         { "CH", canon_hostname },
 145                         { "IP", ip_address },
 146                         { "P", tcp_port },
 147                         { "D", directory },
 148                         { "%", "%" },
 149                         { NULL }
 150                 };
 151
 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", timeout_buf, ".", NULL };
 346
 347         snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 348         return run_service_command(argv);
 349 }
 350
 351 static int upload_archive(void)
 352 {
 353         static const char *argv[] = { "upload-archive", ".", NULL };
 354         return run_service_command(argv);
 355 }
 356
 357 static int receive_pack(void)
 358 {
 359         static const char *argv[] = { "receive-pack", ".", NULL };
 360         return run_service_command(argv);
 361 }
 362
 363 static struct daemon_service daemon_service[] = {
 364         { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 365         { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 366         { "receive-pack", "receivepack", receive_pack, 0, 1 },
 367 };
 368
 369 static void enable_service(const char *name, int ena)
 370 {
 371         int i;
 372         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 373                 if (!strcmp(daemon_service[i].name, name)) {
 374                         daemon_service[i].enabled = ena;
 375                         return;
 376                 }
 377         }
 378         die("No such service %s", name);
 379 }
 380
 381 static void make_service_overridable(const char *name, int ena)
 382 {
 383         int i;
 384         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 385                 if (!strcmp(daemon_service[i].name, name)) {
 386                         daemon_service[i].overridable = ena;
 387                         return;
 388                 }
 389         }
 390         die("No such service %s", name);
 391 }
 392
 393 static char *xstrdup_tolower(const char *str)
 394 {
 395         char *p, *dup = xstrdup(str);
 396         for (p = dup; *p; p++)
 397                 *p = tolower(*p);
 398         return dup;
 399 }
 400
 401 /*
 402  * Read the host as supplied by the client connection.
 403  */
 404 static void parse_host_arg(char *extra_args, int buflen)
 405 {
 406         char *val;
 407         int vallen;
 408         char *end = extra_args + buflen;
 409
 410         if (extra_args < end && *extra_args) {
 411                 saw_extended_args = 1;
 412                 if (strncasecmp("host=", extra_args, 5) == 0) {
 413                         val = extra_args + 5;
 414                         vallen = strlen(val) + 1;
 415                         if (*val) {
 416                                 /* Split <host>:<port> at colon. */
 417                                 char *host = val;
 418                                 char *port = strrchr(host, ':');
 419                                 if (port) {
 420                                         *port = 0;
 421                                         port++;
 422                                         free(tcp_port);
 423                                         tcp_port = xstrdup(port);
 424                                 }
 425                                 free(hostname);
 426                                 hostname = xstrdup_tolower(host);
 427                         }
 428
 429                         /* On to the next one */
 430                         extra_args = val + vallen;
 431                 }
 432                 if (extra_args < end && *extra_args)
 433                         die("Invalid request");
 434         }
 435
 436         /*
 437          * Locate canonical hostname and its IP address.
 438          */
 439         if (hostname) {
 440 #ifndef NO_IPV6
 441                 struct addrinfo hints;
 442                 struct addrinfo *ai;
 443                 int gai;
 444                 static char addrbuf[HOST_NAME_MAX + 1];
 445
 446                 memset(&hints, 0, sizeof(hints));
 447                 hints.ai_flags = AI_CANONNAME;
 448
 449                 gai = getaddrinfo(hostname, NULL, &hints, &ai);
 450                 if (!gai) {
 451                         struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 452
 453                         inet_ntop(AF_INET, &sin_addr->sin_addr,
 454                                   addrbuf, sizeof(addrbuf));
 455                         free(ip_address);
 456                         ip_address = xstrdup(addrbuf);
 457
 458                         free(canon_hostname);
 459                         canon_hostname = xstrdup(ai->ai_canonname ?
 460                                                  ai->ai_canonname : ip_address);
 461
 462                         freeaddrinfo(ai);
 463                 }
 464 #else
 465                 struct hostent *hent;
 466                 struct sockaddr_in sa;
 467                 char **ap;
 468                 static char addrbuf[HOST_NAME_MAX + 1];
 469
 470                 hent = gethostbyname(hostname);
 471
 472                 ap = hent->h_addr_list;
 473                 memset(&sa, 0, sizeof sa);
 474                 sa.sin_family = hent->h_addrtype;
 475                 sa.sin_port = htons(0);
 476                 memcpy(&sa.sin_addr, *ap, hent->h_length);
 477
 478                 inet_ntop(hent->h_addrtype, &sa.sin_addr,
 479                           addrbuf, sizeof(addrbuf));
 480
 481                 free(canon_hostname);
 482                 canon_hostname = xstrdup(hent->h_name);
 483                 free(ip_address);
 484                 ip_address = xstrdup(addrbuf);
 485 #endif
 486         }
 487 }
 488
 489
 490 static int execute(struct sockaddr *addr)
 491 {
 492         static char line[1000];
 493         int pktlen, len, i;
 494
 495         if (addr) {
 496                 char addrbuf[256] = "";
 497                 int port = -1;
 498
 499                 if (addr->sa_family == AF_INET) {
 500                         struct sockaddr_in *sin_addr = (void *) addr;
 501                         inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
 502                         port = ntohs(sin_addr->sin_port);
 503 #ifndef NO_IPV6
 504                 } else if (addr && addr->sa_family == AF_INET6) {
 505                         struct sockaddr_in6 *sin6_addr = (void *) addr;
 506
 507                         char *buf = addrbuf;
 508                         *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 509                         inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
 510                         strcat(buf, "]");
 511
 512                         port = ntohs(sin6_addr->sin6_port);
 513 #endif
 514                 }
 515                 loginfo("Connection from %s:%d", addrbuf, port);
 516                 setenv("REMOTE_ADDR", addrbuf, 1);
 517         }
 518         else {
 519                 unsetenv("REMOTE_ADDR");
 520         }
 521
 522         alarm(init_timeout ? init_timeout : timeout);
 523         pktlen = packet_read_line(0, line, sizeof(line));
 524         alarm(0);
 525
 526         len = strlen(line);
 527         if (pktlen != len)
 528                 loginfo("Extended attributes (%d bytes) exist <%.*s>",
 529                         (int) pktlen - len,
 530                         (int) pktlen - len, line + len + 1);
 531         if (len && line[len-1] == '\n') {
 532                 line[--len] = 0;
 533                 pktlen--;
 534         }
 535
 536         free(hostname);
 537         free(canon_hostname);
 538         free(ip_address);
 539         free(tcp_port);
 540         hostname = canon_hostname = ip_address = tcp_port = NULL;
 541
 542         if (len != pktlen)
 543                 parse_host_arg(line + len + 1, pktlen - len - 1);
 544
 545         for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 546                 struct daemon_service *s = &(daemon_service[i]);
 547                 int namelen = strlen(s->name);
 548                 if (!prefixcmp(line, "git-") &&
 549                     !strncmp(s->name, line + 4, namelen) &&
 550                     line[namelen + 4] == ' ') {
 551                         /*
 552                          * Note: The directory here is probably context sensitive,
 553                          * and might depend on the actual service being performed.
 554                          */
 555                         return run_service(line + namelen + 5, s);
 556                 }
 557         }
 558
 559         logerror("Protocol error: '%s'", line);
 560         return -1;
 561 }
 562
 563 static int max_connections = 32;
 564
 565 static unsigned int live_children;
 566
 567 static struct child {
 568         struct child *next;
 569         pid_t pid;
 570         struct sockaddr_storage address;
 571 } *firstborn;
 572
 573 static void add_child(pid_t pid, struct sockaddr *addr, int addrlen)
 574 {
 575         struct child *newborn, **cradle;
 576
 577         /*
 578          * This must be xcalloc() -- we'll compare the whole sockaddr_storage
 579          * but individual address may be shorter.
 580          */
 581         newborn = xcalloc(1, sizeof(*newborn));
 582         live_children++;
 583         newborn->pid = pid;
 584         memcpy(&newborn->address, addr, addrlen);
 585         for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 586                 if (!memcmp(&(*cradle)->address, &newborn->address,
 587                             sizeof(newborn->address)))
 588                         break;
 589         newborn->next = *cradle;
 590         *cradle = newborn;
 591 }
 592
 593 static void remove_child(pid_t pid)
 594 {
 595         struct child **cradle, *blanket;
 596
 597         for (cradle = &firstborn; (blanket = *cradle); cradle = &blanket->next)
 598                 if (blanket->pid == pid) {
 599                         *cradle = blanket->next;
 600                         live_children--;
 601                         free(blanket);
 602                         break;
 603                 }
 604 }
 605
 606 /*
 607  * This gets called if the number of connections grows
 608  * past "max_connections".
 609  *
 610  * We kill the newest connection from a duplicate IP.
 611  */
 612 static void kill_some_child(void)
 613 {
 614         const struct child *blanket, *next;
 615
 616         if (!(blanket = firstborn))
 617                 return;
 618
 619         for (; (next = blanket->next); blanket = next)
 620                 if (!memcmp(&blanket->address, &next->address,
 621                             sizeof(next->address))) {
 622                         kill(blanket->pid, SIGTERM);
 623                         break;
 624                 }
 625 }
 626
 627 static void check_dead_children(void)
 628 {
 629         int status;
 630         pid_t pid;
 631
 632         while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
 633                 const char *dead = "";
 634                 remove_child(pid);
 635                 if (!WIFEXITED(status) || (WEXITSTATUS(status) > 0))
 636                         dead = " (with error)";
 637                 loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 638         }
 639 }
 640
 641 static void handle(int incoming, struct sockaddr *addr, int addrlen)
 642 {
 643         pid_t pid;
 644
 645         if (max_connections && live_children >= max_connections) {
 646                 kill_some_child();
 647                 sleep(1);  /* give it some time to die */
 648                 check_dead_children();
 649                 if (live_children >= max_connections) {
 650                         close(incoming);
 651                         logerror("Too many children, dropping connection");
 652                         return;
 653                 }
 654         }
 655
 656         if ((pid = fork())) {
 657                 close(incoming);
 658                 if (pid < 0) {
 659                         logerror("Couldn't fork %s", strerror(errno));
 660                         return;
 661                 }
 662
 663                 add_child(pid, addr, addrlen);
 664                 return;
 665         }
 666
 667         dup2(incoming, 0);
 668         dup2(incoming, 1);
 669         close(incoming);
 670
 671         exit(execute(addr));
 672 }
 673
 674 static void child_handler(int signo)
 675 {
 676         /*
 677          * Otherwise empty handler because systemcalls will get interrupted
 678          * upon signal receipt
 679          * SysV needs the handler to be rearmed
 680          */
 681         signal(SIGCHLD, child_handler);
 682 }
 683
 684 static int set_reuse_addr(int sockfd)
 685 {
 686         int on = 1;
 687
 688         if (!reuseaddr)
 689                 return 0;
 690         return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 691                           &on, sizeof(on));
 692 }
 693
 694 #ifndef NO_IPV6
 695
 696 static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 697 {
 698         int socknum = 0, *socklist = NULL;
 699         int maxfd = -1;
 700         char pbuf[NI_MAXSERV];
 701         struct addrinfo hints, *ai0, *ai;
 702         int gai;
 703         long flags;
 704
 705         sprintf(pbuf, "%d", listen_port);
 706         memset(&hints, 0, sizeof(hints));
 707         hints.ai_family = AF_UNSPEC;
 708         hints.ai_socktype = SOCK_STREAM;
 709         hints.ai_protocol = IPPROTO_TCP;
 710         hints.ai_flags = AI_PASSIVE;
 711
 712         gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 713         if (gai)
 714                 die("getaddrinfo() failed: %s", gai_strerror(gai));
 715
 716         for (ai = ai0; ai; ai = ai->ai_next) {
 717                 int sockfd;
 718
 719                 sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 720                 if (sockfd < 0)
 721                         continue;
 722                 if (sockfd >= FD_SETSIZE) {
 723                         logerror("Socket descriptor too large");
 724                         close(sockfd);
 725                         continue;
 726                 }
 727
 728 #ifdef IPV6_V6ONLY
 729                 if (ai->ai_family == AF_INET6) {
 730                         int on = 1;
 731                         setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 732                                    &on, sizeof(on));
 733                         /* Note: error is not fatal */
 734                 }
 735 #endif
 736
 737                 if (set_reuse_addr(sockfd)) {
 738                         close(sockfd);
 739                         continue;
 740                 }
 741
 742                 if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 743                         close(sockfd);
 744                         continue;       /* not fatal */
 745                 }
 746                 if (listen(sockfd, 5) < 0) {
 747                         close(sockfd);
 748                         continue;       /* not fatal */
 749                 }
 750
 751                 flags = fcntl(sockfd, F_GETFD, 0);
 752                 if (flags >= 0)
 753                         fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 754
 755                 socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
 756                 socklist[socknum++] = sockfd;
 757
 758                 if (maxfd < sockfd)
 759                         maxfd = sockfd;
 760         }
 761
 762         freeaddrinfo(ai0);
 763
 764         *socklist_p = socklist;
 765         return socknum;
 766 }
 767
 768 #else /* NO_IPV6 */
 769
 770 static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 771 {
 772         struct sockaddr_in sin;
 773         int sockfd;
 774         long flags;
 775
 776         memset(&sin, 0, sizeof sin);
 777         sin.sin_family = AF_INET;
 778         sin.sin_port = htons(listen_port);
 779
 780         if (listen_addr) {
 781                 /* Well, host better be an IP address here. */
 782                 if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 783                         return 0;
 784         } else {
 785                 sin.sin_addr.s_addr = htonl(INADDR_ANY);
 786         }
 787
 788         sockfd = socket(AF_INET, SOCK_STREAM, 0);
 789         if (sockfd < 0)
 790                 return 0;
 791
 792         if (set_reuse_addr(sockfd)) {
 793                 close(sockfd);
 794                 return 0;
 795         }
 796
 797         if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 798                 close(sockfd);
 799                 return 0;
 800         }
 801
 802         if (listen(sockfd, 5) < 0) {
 803                 close(sockfd);
 804                 return 0;
 805         }
 806
 807         flags = fcntl(sockfd, F_GETFD, 0);
 808         if (flags >= 0)
 809                 fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 810
 811         *socklist_p = xmalloc(sizeof(int));
 812         **socklist_p = sockfd;
 813         return 1;
 814 }
 815
 816 #endif
 817
 818 static int service_loop(int socknum, int *socklist)
 819 {
 820         struct pollfd *pfd;
 821         int i;
 822
 823         pfd = xcalloc(socknum, sizeof(struct pollfd));
 824
 825         for (i = 0; i < socknum; i++) {
 826                 pfd[i].fd = socklist[i];
 827                 pfd[i].events = POLLIN;
 828         }
 829
 830         signal(SIGCHLD, child_handler);
 831
 832         for (;;) {
 833                 int i;
 834
 835                 check_dead_children();
 836
 837                 if (poll(pfd, socknum, -1) < 0) {
 838                         if (errno != EINTR) {
 839                                 logerror("Poll failed, resuming: %s",
 840                                       strerror(errno));
 841                                 sleep(1);
 842                         }
 843                         continue;
 844                 }
 845
 846                 for (i = 0; i < socknum; i++) {
 847                         if (pfd[i].revents & POLLIN) {
 848                                 struct sockaddr_storage ss;
 849                                 unsigned int sslen = sizeof(ss);
 850                                 int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
 851                                 if (incoming < 0) {
 852                                         switch (errno) {
 853                                         case EAGAIN:
 854                                         case EINTR:
 855                                         case ECONNABORTED:
 856                                                 continue;
 857                                         default:
 858                                                 die_errno("accept returned");
 859                                         }
 860                                 }
 861                                 handle(incoming, (struct sockaddr *)&ss, sslen);
 862                         }
 863                 }
 864         }
 865 }
 866
 867 /* if any standard file descriptor is missing open it to /dev/null */
 868 static void sanitize_stdfds(void)
 869 {
 870         int fd = open("/dev/null", O_RDWR, 0);
 871         while (fd != -1 && fd < 2)
 872                 fd = dup(fd);
 873         if (fd == -1)
 874                 die_errno("open /dev/null or dup failed");
 875         if (fd > 2)
 876                 close(fd);
 877 }
 878
 879 static void daemonize(void)
 880 {
 881         switch (fork()) {
 882                 case 0:
 883                         break;
 884                 case -1:
 885                         die_errno("fork failed");
 886                 default:
 887                         exit(0);
 888         }
 889         if (setsid() == -1)
 890                 die_errno("setsid failed");
 891         close(0);
 892         close(1);
 893         close(2);
 894         sanitize_stdfds();
 895 }
 896
 897 static void store_pid(const char *path)
 898 {
 899         FILE *f = fopen(path, "w");
 900         if (!f)
 901                 die_errno("cannot open pid file '%s'", path);
 902         if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
 903                 die_errno("failed to write pid file '%s'", path);
 904 }
 905
 906 static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
 907 {
 908         int socknum, *socklist;
 909
 910         socknum = socksetup(listen_addr, listen_port, &socklist);
 911         if (socknum == 0)
 912                 die("unable to allocate any listen sockets on host %s port %u",
 913                     listen_addr, listen_port);
 914
 915         if (pass && gid &&
 916             (initgroups(pass->pw_name, gid) || setgid (gid) ||
 917              setuid(pass->pw_uid)))
 918                 die("cannot drop privileges");
 919
 920         return service_loop(socknum, socklist);
 921 }
 922
 923 int main(int argc, char **argv)
 924 {
 925         int listen_port = 0;
 926         char *listen_addr = NULL;
 927         int inetd_mode = 0;
 928         const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
 929         int detach = 0;
 930         struct passwd *pass = NULL;
 931         struct group *group;
 932         gid_t gid = 0;
 933         int i;
 934
 935         git_extract_argv0_path(argv[0]);
 936
 937         for (i = 1; i < argc; i++) {
 938                 char *arg = argv[i];
 939
 940                 if (!prefixcmp(arg, "--listen=")) {
 941                         listen_addr = xstrdup_tolower(arg + 9);
 942                         continue;
 943                 }
 944                 if (!prefixcmp(arg, "--port=")) {
 945                         char *end;
 946                         unsigned long n;
 947                         n = strtoul(arg+7, &end, 0);
 948                         if (arg[7] && !*end) {
 949                                 listen_port = n;
 950                                 continue;
 951                         }
 952                 }
 953                 if (!strcmp(arg, "--inetd")) {
 954                         inetd_mode = 1;
 955                         log_syslog = 1;
 956                         continue;
 957                 }
 958                 if (!strcmp(arg, "--verbose")) {
 959                         verbose = 1;
 960                         continue;
 961                 }
 962                 if (!strcmp(arg, "--syslog")) {
 963                         log_syslog = 1;
 964                         continue;
 965                 }
 966                 if (!strcmp(arg, "--export-all")) {
 967                         export_all_trees = 1;
 968                         continue;
 969                 }
 970                 if (!prefixcmp(arg, "--timeout=")) {
 971                         timeout = atoi(arg+10);
 972                         continue;
 973                 }
 974                 if (!prefixcmp(arg, "--init-timeout=")) {
 975                         init_timeout = atoi(arg+15);
 976                         continue;
 977                 }
 978                 if (!prefixcmp(arg, "--max-connections=")) {
 979                         max_connections = atoi(arg+18);
 980                         if (max_connections < 0)
 981                                 max_connections = 0;            /* unlimited */
 982                         continue;
 983                 }
 984                 if (!strcmp(arg, "--strict-paths")) {
 985                         strict_paths = 1;
 986                         continue;
 987                 }
 988                 if (!prefixcmp(arg, "--base-path=")) {
 989                         base_path = arg+12;
 990                         continue;
 991                 }
 992                 if (!strcmp(arg, "--base-path-relaxed")) {
 993                         base_path_relaxed = 1;
 994                         continue;
 995                 }
 996                 if (!prefixcmp(arg, "--interpolated-path=")) {
 997                         interpolated_path = arg+20;
 998                         continue;
 999                 }
1000                 if (!strcmp(arg, "--reuseaddr")) {
1001                         reuseaddr = 1;
1002                         continue;
1003                 }
1004                 if (!strcmp(arg, "--user-path")) {
1005                         user_path = "";
1006                         continue;
1007                 }
1008                 if (!prefixcmp(arg, "--user-path=")) {
1009                         user_path = arg + 12;
1010                         continue;
1011                 }
1012                 if (!prefixcmp(arg, "--pid-file=")) {
1013                         pid_file = arg + 11;
1014                         continue;
1015                 }
1016                 if (!strcmp(arg, "--detach")) {
1017                         detach = 1;
1018                         log_syslog = 1;
1019                         continue;
1020                 }
1021                 if (!prefixcmp(arg, "--user=")) {
1022                         user_name = arg + 7;
1023                         continue;
1024                 }
1025                 if (!prefixcmp(arg, "--group=")) {
1026                         group_name = arg + 8;
1027                         continue;
1028                 }
1029                 if (!prefixcmp(arg, "--enable=")) {
1030                         enable_service(arg + 9, 1);
1031                         continue;
1032                 }
1033                 if (!prefixcmp(arg, "--disable=")) {
1034                         enable_service(arg + 10, 0);
1035                         continue;
1036                 }
1037                 if (!prefixcmp(arg, "--allow-override=")) {
1038                         make_service_overridable(arg + 17, 1);
1039                         continue;
1040                 }
1041                 if (!prefixcmp(arg, "--forbid-override=")) {
1042                         make_service_overridable(arg + 18, 0);
1043                         continue;
1044                 }
1045                 if (!strcmp(arg, "--")) {
1046                         ok_paths = &argv[i+1];
1047                         break;
1048                 } else if (arg[0] != '-') {
1049                         ok_paths = &argv[i];
1050                         break;
1051                 }
1052
1053                 usage(daemon_usage);
1054         }
1055
1056         if (log_syslog) {
1057                 openlog("git-daemon", LOG_PID, LOG_DAEMON);
1058                 set_die_routine(daemon_die);
1059         } else
1060                 /* avoid splitting a message in the middle */
1061                 setvbuf(stderr, NULL, _IOLBF, 0);
1062
1063         if (inetd_mode && (group_name || user_name))
1064                 die("--user and --group are incompatible with --inetd");
1065
1066         if (inetd_mode && (listen_port || listen_addr))
1067                 die("--listen= and --port= are incompatible with --inetd");
1068         else if (listen_port == 0)
1069                 listen_port = DEFAULT_GIT_PORT;
1070
1071         if (group_name && !user_name)
1072                 die("--group supplied without --user");
1073
1074         if (user_name) {
1075                 pass = getpwnam(user_name);
1076                 if (!pass)
1077                         die("user not found - %s", user_name);
1078
1079                 if (!group_name)
1080                         gid = pass->pw_gid;
1081                 else {
1082                         group = getgrnam(group_name);
1083                         if (!group)
1084                                 die("group not found - %s", group_name);
1085
1086                         gid = group->gr_gid;
1087                 }
1088         }
1089
1090         if (strict_paths && (!ok_paths || !*ok_paths))
1091                 die("option --strict-paths requires a whitelist");
1092
1093         if (base_path && !is_directory(base_path))
1094                 die("base-path '%s' does not exist or is not a directory",
1095                     base_path);
1096
1097         if (inetd_mode) {
1098                 struct sockaddr_storage ss;
1099                 struct sockaddr *peer = (struct sockaddr *)&ss;
1100                 socklen_t slen = sizeof(ss);
1101
1102                 if (!freopen("/dev/null", "w", stderr))
1103                         die_errno("failed to redirect stderr to /dev/null");
1104
1105                 if (getpeername(0, peer, &slen))
1106                         peer = NULL;
1107
1108                 return execute(peer);
1109         }
1110
1111         if (detach) {
1112                 daemonize();
1113                 loginfo("Ready to rumble");
1114         }
1115         else
1116                 sanitize_stdfds();
1117
1118         if (pid_file)
1119                 store_pid(pid_file);
1120
1121         return serve(listen_addr, listen_port, pass, gid);
1122 }