Andrew's git / gitweb.git / daemon.c
?
daemon.con commit git-checkout: be careful about untracked symlinks (b6986d8)
   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
  17static int log_syslog;
  18static int verbose;
  19static int reuseaddr;
  20
  21static 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 */
  34static char **ok_paths;
  35static int strict_paths;
  36
  37/* If this is set, git-daemon-export-ok is not required */
  38static int export_all_trees;
  39
  40/* Take all paths relative to this one if non-NULL */
  41static char *base_path;
  42static char *interpolated_path;
  43static int base_path_relaxed;
  44
  45/* Flag indicating client sent extra args. */
  46static 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 */
  52static const char *user_path;
  53
  54/* Timeout, and initial timeout */
  55static unsigned int timeout;
  56static unsigned int init_timeout;
  57
  58static char *hostname;
  59static char *canon_hostname;
  60static char *ip_address;
  61static char *tcp_port;
  62
  63static 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
  80static 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
  88static 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
  98static void NORETURN daemon_die(const char *err, va_list params)
  99{
 100        logreport(LOG_ERR, err, params);
 101        exit(1);
 102}
 103
 104static int avoid_alias(char *p)
 105{
 106        int sl, ndot;
 107
 108        /*
 109         * This resurrects the belts and suspenders paranoia check by HPA
 110         * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
 111         * does not do getcwd() based path canonicalizations.
 112         *
 113         * sl becomes true immediately after seeing '/' and continues to
 114         * be true as long as dots continue after that without intervening
 115         * non-dot character.
 116         */
 117        if (!p || (*p != '/' && *p != '~'))
 118                return -1;
 119        sl = 1; ndot = 0;
 120        p++;
 121
 122        while (1) {
 123                char ch = *p++;
 124                if (sl) {
 125                        if (ch == '.')
 126                                ndot++;
 127                        else if (ch == '/') {
 128                                if (ndot < 3)
 129                                        /* reject //, /./ and /../ */
 130                                        return -1;
 131                                ndot = 0;
 132                        }
 133                        else if (ch == 0) {
 134                                if (0 < ndot && ndot < 3)
 135                                        /* reject /.$ and /..$ */
 136                                        return -1;
 137                                return 0;
 138                        }
 139                        else
 140                                sl = ndot = 0;
 141                }
 142                else if (ch == 0)
 143                        return 0;
 144                else if (ch == '/') {
 145                        sl = 1;
 146                        ndot = 0;
 147                }
 148        }
 149}
 150
 151static char *path_ok(char *directory)
 152{
 153        static char rpath[PATH_MAX];
 154        static char interp_path[PATH_MAX];
 155        char *path;
 156        char *dir;
 157
 158        dir = directory;
 159
 160        if (avoid_alias(dir)) {
 161                logerror("'%s': aliased", dir);
 162                return NULL;
 163        }
 164
 165        if (*dir == '~') {
 166                if (!user_path) {
 167                        logerror("'%s': User-path not allowed", dir);
 168                        return NULL;
 169                }
 170                if (*user_path) {
 171                        /* Got either "~alice" or "~alice/foo";
 172                         * rewrite them to "~alice/%s" or
 173                         * "~alice/%s/foo".
 174                         */
 175                        int namlen, restlen = strlen(dir);
 176                        char *slash = strchr(dir, '/');
 177                        if (!slash)
 178                                slash = dir + restlen;
 179                        namlen = slash - dir;
 180                        restlen -= namlen;
 181                        loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
 182                        snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
 183                                 namlen, dir, user_path, restlen, slash);
 184                        dir = rpath;
 185                }
 186        }
 187        else if (interpolated_path && saw_extended_args) {
 188                struct strbuf expanded_path = STRBUF_INIT;
 189                struct strbuf_expand_dict_entry dict[] = {
 190                        { "H", hostname },
 191                        { "CH", canon_hostname },
 192                        { "IP", ip_address },
 193                        { "P", tcp_port },
 194                        { "D", directory },
 195                        { "%", "%" },
 196                        { NULL }
 197                };
 198
 199                if (*dir != '/') {
 200                        /* Allow only absolute */
 201                        logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 202                        return NULL;
 203                }
 204
 205                strbuf_expand(&expanded_path, interpolated_path,
 206                                strbuf_expand_dict_cb, &dict);
 207                strlcpy(interp_path, expanded_path.buf, PATH_MAX);
 208                strbuf_release(&expanded_path);
 209                loginfo("Interpolated dir '%s'", interp_path);
 210
 211                dir = interp_path;
 212        }
 213        else if (base_path) {
 214                if (*dir != '/') {
 215                        /* Allow only absolute */
 216                        logerror("'%s': Non-absolute path denied (base-path active)", dir);
 217                        return NULL;
 218                }
 219                snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
 220                dir = rpath;
 221        }
 222
 223        path = enter_repo(dir, strict_paths);
 224        if (!path && base_path && base_path_relaxed) {
 225                /*
 226                 * if we fail and base_path_relaxed is enabled, try without
 227                 * prefixing the base path
 228                 */
 229                dir = directory;
 230                path = enter_repo(dir, strict_paths);
 231        }
 232
 233        if (!path) {
 234                logerror("'%s' does not appear to be a git repository", dir);
 235                return NULL;
 236        }
 237
 238        if ( ok_paths && *ok_paths ) {
 239                char **pp;
 240                int pathlen = strlen(path);
 241
 242                /* The validation is done on the paths after enter_repo
 243                 * appends optional {.git,.git/.git} and friends, but
 244                 * it does not use getcwd().  So if your /pub is
 245                 * a symlink to /mnt/pub, you can whitelist /pub and
 246                 * do not have to say /mnt/pub.
 247                 * Do not say /pub/.
 248                 */
 249                for ( pp = ok_paths ; *pp ; pp++ ) {
 250                        int len = strlen(*pp);
 251                        if (len <= pathlen &&
 252                            !memcmp(*pp, path, len) &&
 253                            (path[len] == '\0' ||
 254                             (!strict_paths && path[len] == '/')))
 255                                return path;
 256                }
 257        }
 258        else {
 259                /* be backwards compatible */
 260                if (!strict_paths)
 261                        return path;
 262        }
 263
 264        logerror("'%s': not in whitelist", path);
 265        return NULL;            /* Fallthrough. Deny by default */
 266}
 267
 268typedef int (*daemon_service_fn)(void);
 269struct daemon_service {
 270        const char *name;
 271        const char *config_name;
 272        daemon_service_fn fn;
 273        int enabled;
 274        int overridable;
 275};
 276
 277static struct daemon_service *service_looking_at;
 278static int service_enabled;
 279
 280static int git_daemon_config(const char *var, const char *value, void *cb)
 281{
 282        if (!prefixcmp(var, "daemon.") &&
 283            !strcmp(var + 7, service_looking_at->config_name)) {
 284                service_enabled = git_config_bool(var, value);
 285                return 0;
 286        }
 287
 288        /* we are not interested in parsing any other configuration here */
 289        return 0;
 290}
 291
 292static int run_service(char *dir, struct daemon_service *service)
 293{
 294        const char *path;
 295        int enabled = service->enabled;
 296
 297        loginfo("Request %s for '%s'", service->name, dir);
 298
 299        if (!enabled && !service->overridable) {
 300                logerror("'%s': service not enabled.", service->name);
 301                errno = EACCES;
 302                return -1;
 303        }
 304
 305        if (!(path = path_ok(dir)))
 306                return -1;
 307
 308        /*
 309         * Security on the cheap.
 310         *
 311         * We want a readable HEAD, usable "objects" directory, and
 312         * a "git-daemon-export-ok" flag that says that the other side
 313         * is ok with us doing this.
 314         *
 315         * path_ok() uses enter_repo() and does whitelist checking.
 316         * We only need to make sure the repository is exported.
 317         */
 318
 319        if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 320                logerror("'%s': repository not exported.", path);
 321                errno = EACCES;
 322                return -1;
 323        }
 324
 325        if (service->overridable) {
 326                service_looking_at = service;
 327                service_enabled = -1;
 328                git_config(git_daemon_config, NULL);
 329                if (0 <= service_enabled)
 330                        enabled = service_enabled;
 331        }
 332        if (!enabled) {
 333                logerror("'%s': service not enabled for '%s'",
 334                         service->name, path);
 335                errno = EACCES;
 336                return -1;
 337        }
 338
 339        /*
 340         * We'll ignore SIGTERM from now on, we have a
 341         * good client.
 342         */
 343        signal(SIGTERM, SIG_IGN);
 344
 345        return service->fn();
 346}
 347
 348static void copy_to_log(int fd)
 349{
 350        struct strbuf line = STRBUF_INIT;
 351        FILE *fp;
 352
 353        fp = fdopen(fd, "r");
 354        if (fp == NULL) {
 355                logerror("fdopen of error channel failed");
 356                close(fd);
 357                return;
 358        }
 359
 360        while (strbuf_getline(&line, fp, '\n') != EOF) {
 361                logerror("%s", line.buf);
 362                strbuf_setlen(&line, 0);
 363        }
 364
 365        strbuf_release(&line);
 366        fclose(fp);
 367}
 368
 369static int run_service_command(const char **argv)
 370{
 371        struct child_process cld;
 372
 373        memset(&cld, 0, sizeof(cld));
 374        cld.argv = argv;
 375        cld.git_cmd = 1;
 376        cld.err = -1;
 377        if (start_command(&cld))
 378                return -1;
 379
 380        close(0);
 381        close(1);
 382
 383        copy_to_log(cld.err);
 384
 385        return finish_command(&cld);
 386}
 387
 388static int upload_pack(void)
 389{
 390        /* Timeout as string */
 391        char timeout_buf[64];
 392        const char *argv[] = { "upload-pack", "--strict", timeout_buf, ".", NULL };
 393
 394        snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 395        return run_service_command(argv);
 396}
 397
 398static int upload_archive(void)
 399{
 400        static const char *argv[] = { "upload-archive", ".", NULL };
 401        return run_service_command(argv);
 402}
 403
 404static int receive_pack(void)
 405{
 406        static const char *argv[] = { "receive-pack", ".", NULL };
 407        return run_service_command(argv);
 408}
 409
 410static struct daemon_service daemon_service[] = {
 411        { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 412        { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 413        { "receive-pack", "receivepack", receive_pack, 0, 1 },
 414};
 415
 416static void enable_service(const char *name, int ena)
 417{
 418        int i;
 419        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 420                if (!strcmp(daemon_service[i].name, name)) {
 421                        daemon_service[i].enabled = ena;
 422                        return;
 423                }
 424        }
 425        die("No such service %s", name);
 426}
 427
 428static void make_service_overridable(const char *name, int ena)
 429{
 430        int i;
 431        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 432                if (!strcmp(daemon_service[i].name, name)) {
 433                        daemon_service[i].overridable = ena;
 434                        return;
 435                }
 436        }
 437        die("No such service %s", name);
 438}
 439
 440static char *xstrdup_tolower(const char *str)
 441{
 442        char *p, *dup = xstrdup(str);
 443        for (p = dup; *p; p++)
 444                *p = tolower(*p);
 445        return dup;
 446}
 447
 448/*
 449 * Read the host as supplied by the client connection.
 450 */
 451static void parse_host_arg(char *extra_args, int buflen)
 452{
 453        char *val;
 454        int vallen;
 455        char *end = extra_args + buflen;
 456
 457        if (extra_args < end && *extra_args) {
 458                saw_extended_args = 1;
 459                if (strncasecmp("host=", extra_args, 5) == 0) {
 460                        val = extra_args + 5;
 461                        vallen = strlen(val) + 1;
 462                        if (*val) {
 463                                /* Split <host>:<port> at colon. */
 464                                char *host = val;
 465                                char *port = strrchr(host, ':');
 466                                if (port) {
 467                                        *port = 0;
 468                                        port++;
 469                                        free(tcp_port);
 470                                        tcp_port = xstrdup(port);
 471                                }
 472                                free(hostname);
 473                                hostname = xstrdup_tolower(host);
 474                        }
 475
 476                        /* On to the next one */
 477                        extra_args = val + vallen;
 478                }
 479                if (extra_args < end && *extra_args)
 480                        die("Invalid request");
 481        }
 482
 483        /*
 484         * Locate canonical hostname and its IP address.
 485         */
 486        if (hostname) {
 487#ifndef NO_IPV6
 488                struct addrinfo hints;
 489                struct addrinfo *ai;
 490                int gai;
 491                static char addrbuf[HOST_NAME_MAX + 1];
 492
 493                memset(&hints, 0, sizeof(hints));
 494                hints.ai_flags = AI_CANONNAME;
 495
 496                gai = getaddrinfo(hostname, NULL, &hints, &ai);
 497                if (!gai) {
 498                        struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 499
 500                        inet_ntop(AF_INET, &sin_addr->sin_addr,
 501                                  addrbuf, sizeof(addrbuf));
 502                        free(ip_address);
 503                        ip_address = xstrdup(addrbuf);
 504
 505                        free(canon_hostname);
 506                        canon_hostname = xstrdup(ai->ai_canonname ?
 507                                                 ai->ai_canonname : ip_address);
 508
 509                        freeaddrinfo(ai);
 510                }
 511#else
 512                struct hostent *hent;
 513                struct sockaddr_in sa;
 514                char **ap;
 515                static char addrbuf[HOST_NAME_MAX + 1];
 516
 517                hent = gethostbyname(hostname);
 518
 519                ap = hent->h_addr_list;
 520                memset(&sa, 0, sizeof sa);
 521                sa.sin_family = hent->h_addrtype;
 522                sa.sin_port = htons(0);
 523                memcpy(&sa.sin_addr, *ap, hent->h_length);
 524
 525                inet_ntop(hent->h_addrtype, &sa.sin_addr,
 526                          addrbuf, sizeof(addrbuf));
 527
 528                free(canon_hostname);
 529                canon_hostname = xstrdup(hent->h_name);
 530                free(ip_address);
 531                ip_address = xstrdup(addrbuf);
 532#endif
 533        }
 534}
 535
 536
 537static int execute(struct sockaddr *addr)
 538{
 539        static char line[1000];
 540        int pktlen, len, i;
 541
 542        if (addr) {
 543                char addrbuf[256] = "";
 544                int port = -1;
 545
 546                if (addr->sa_family == AF_INET) {
 547                        struct sockaddr_in *sin_addr = (void *) addr;
 548                        inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
 549                        port = ntohs(sin_addr->sin_port);
 550#ifndef NO_IPV6
 551                } else if (addr && addr->sa_family == AF_INET6) {
 552                        struct sockaddr_in6 *sin6_addr = (void *) addr;
 553
 554                        char *buf = addrbuf;
 555                        *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 556                        inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
 557                        strcat(buf, "]");
 558
 559                        port = ntohs(sin6_addr->sin6_port);
 560#endif
 561                }
 562                loginfo("Connection from %s:%d", addrbuf, port);
 563                setenv("REMOTE_ADDR", addrbuf, 1);
 564        }
 565        else {
 566                unsetenv("REMOTE_ADDR");
 567        }
 568
 569        alarm(init_timeout ? init_timeout : timeout);
 570        pktlen = packet_read_line(0, line, sizeof(line));
 571        alarm(0);
 572
 573        len = strlen(line);
 574        if (pktlen != len)
 575                loginfo("Extended attributes (%d bytes) exist <%.*s>",
 576                        (int) pktlen - len,
 577                        (int) pktlen - len, line + len + 1);
 578        if (len && line[len-1] == '\n') {
 579                line[--len] = 0;
 580                pktlen--;
 581        }
 582
 583        free(hostname);
 584        free(canon_hostname);
 585        free(ip_address);
 586        free(tcp_port);
 587        hostname = canon_hostname = ip_address = tcp_port = NULL;
 588
 589        if (len != pktlen)
 590                parse_host_arg(line + len + 1, pktlen - len - 1);
 591
 592        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 593                struct daemon_service *s = &(daemon_service[i]);
 594                int namelen = strlen(s->name);
 595                if (!prefixcmp(line, "git-") &&
 596                    !strncmp(s->name, line + 4, namelen) &&
 597                    line[namelen + 4] == ' ') {
 598                        /*
 599                         * Note: The directory here is probably context sensitive,
 600                         * and might depend on the actual service being performed.
 601                         */
 602                        return run_service(line + namelen + 5, s);
 603                }
 604        }
 605
 606        logerror("Protocol error: '%s'", line);
 607        return -1;
 608}
 609
 610static int max_connections = 32;
 611
 612static unsigned int live_children;
 613
 614static struct child {
 615        struct child *next;
 616        pid_t pid;
 617        struct sockaddr_storage address;
 618} *firstborn;
 619
 620static void add_child(pid_t pid, struct sockaddr *addr, int addrlen)
 621{
 622        struct child *newborn, **cradle;
 623
 624        /*
 625         * This must be xcalloc() -- we'll compare the whole sockaddr_storage
 626         * but individual address may be shorter.
 627         */
 628        newborn = xcalloc(1, sizeof(*newborn));
 629        live_children++;
 630        newborn->pid = pid;
 631        memcpy(&newborn->address, addr, addrlen);
 632        for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 633                if (!memcmp(&(*cradle)->address, &newborn->address,
 634                            sizeof(newborn->address)))
 635                        break;
 636        newborn->next = *cradle;
 637        *cradle = newborn;
 638}
 639
 640static void remove_child(pid_t pid)
 641{
 642        struct child **cradle, *blanket;
 643
 644        for (cradle = &firstborn; (blanket = *cradle); cradle = &blanket->next)
 645                if (blanket->pid == pid) {
 646                        *cradle = blanket->next;
 647                        live_children--;
 648                        free(blanket);
 649                        break;
 650                }
 651}
 652
 653/*
 654 * This gets called if the number of connections grows
 655 * past "max_connections".
 656 *
 657 * We kill the newest connection from a duplicate IP.
 658 */
 659static void kill_some_child(void)
 660{
 661        const struct child *blanket, *next;
 662
 663        if (!(blanket = firstborn))
 664                return;
 665
 666        for (; (next = blanket->next); blanket = next)
 667                if (!memcmp(&blanket->address, &next->address,
 668                            sizeof(next->address))) {
 669                        kill(blanket->pid, SIGTERM);
 670                        break;
 671                }
 672}
 673
 674static void check_dead_children(void)
 675{
 676        int status;
 677        pid_t pid;
 678
 679        while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
 680                const char *dead = "";
 681                remove_child(pid);
 682                if (!WIFEXITED(status) || (WEXITSTATUS(status) > 0))
 683                        dead = " (with error)";
 684                loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 685        }
 686}
 687
 688static void handle(int incoming, struct sockaddr *addr, int addrlen)
 689{
 690        pid_t pid;
 691
 692        if (max_connections && live_children >= max_connections) {
 693                kill_some_child();
 694                sleep(1);  /* give it some time to die */
 695                check_dead_children();
 696                if (live_children >= max_connections) {
 697                        close(incoming);
 698                        logerror("Too many children, dropping connection");
 699                        return;
 700                }
 701        }
 702
 703        if ((pid = fork())) {
 704                close(incoming);
 705                if (pid < 0) {
 706                        logerror("Couldn't fork %s", strerror(errno));
 707                        return;
 708                }
 709
 710                add_child(pid, addr, addrlen);
 711                return;
 712        }
 713
 714        dup2(incoming, 0);
 715        dup2(incoming, 1);
 716        close(incoming);
 717
 718        exit(execute(addr));
 719}
 720
 721static void child_handler(int signo)
 722{
 723        /*
 724         * Otherwise empty handler because systemcalls will get interrupted
 725         * upon signal receipt
 726         * SysV needs the handler to be rearmed
 727         */
 728        signal(SIGCHLD, child_handler);
 729}
 730
 731static int set_reuse_addr(int sockfd)
 732{
 733        int on = 1;
 734
 735        if (!reuseaddr)
 736                return 0;
 737        return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 738                          &on, sizeof(on));
 739}
 740
 741#ifndef NO_IPV6
 742
 743static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 744{
 745        int socknum = 0, *socklist = NULL;
 746        int maxfd = -1;
 747        char pbuf[NI_MAXSERV];
 748        struct addrinfo hints, *ai0, *ai;
 749        int gai;
 750        long flags;
 751
 752        sprintf(pbuf, "%d", listen_port);
 753        memset(&hints, 0, sizeof(hints));
 754        hints.ai_family = AF_UNSPEC;
 755        hints.ai_socktype = SOCK_STREAM;
 756        hints.ai_protocol = IPPROTO_TCP;
 757        hints.ai_flags = AI_PASSIVE;
 758
 759        gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 760        if (gai)
 761                die("getaddrinfo() failed: %s", gai_strerror(gai));
 762
 763        for (ai = ai0; ai; ai = ai->ai_next) {
 764                int sockfd;
 765
 766                sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 767                if (sockfd < 0)
 768                        continue;
 769                if (sockfd >= FD_SETSIZE) {
 770                        logerror("Socket descriptor too large");
 771                        close(sockfd);
 772                        continue;
 773                }
 774
 775#ifdef IPV6_V6ONLY
 776                if (ai->ai_family == AF_INET6) {
 777                        int on = 1;
 778                        setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 779                                   &on, sizeof(on));
 780                        /* Note: error is not fatal */
 781                }
 782#endif
 783
 784                if (set_reuse_addr(sockfd)) {
 785                        close(sockfd);
 786                        continue;
 787                }
 788
 789                if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 790                        close(sockfd);
 791                        continue;       /* not fatal */
 792                }
 793                if (listen(sockfd, 5) < 0) {
 794                        close(sockfd);
 795                        continue;       /* not fatal */
 796                }
 797
 798                flags = fcntl(sockfd, F_GETFD, 0);
 799                if (flags >= 0)
 800                        fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 801
 802                socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
 803                socklist[socknum++] = sockfd;
 804
 805                if (maxfd < sockfd)
 806                        maxfd = sockfd;
 807        }
 808
 809        freeaddrinfo(ai0);
 810
 811        *socklist_p = socklist;
 812        return socknum;
 813}
 814
 815#else /* NO_IPV6 */
 816
 817static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 818{
 819        struct sockaddr_in sin;
 820        int sockfd;
 821        long flags;
 822
 823        memset(&sin, 0, sizeof sin);
 824        sin.sin_family = AF_INET;
 825        sin.sin_port = htons(listen_port);
 826
 827        if (listen_addr) {
 828                /* Well, host better be an IP address here. */
 829                if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 830                        return 0;
 831        } else {
 832                sin.sin_addr.s_addr = htonl(INADDR_ANY);
 833        }
 834
 835        sockfd = socket(AF_INET, SOCK_STREAM, 0);
 836        if (sockfd < 0)
 837                return 0;
 838
 839        if (set_reuse_addr(sockfd)) {
 840                close(sockfd);
 841                return 0;
 842        }
 843
 844        if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 845                close(sockfd);
 846                return 0;
 847        }
 848
 849        if (listen(sockfd, 5) < 0) {
 850                close(sockfd);
 851                return 0;
 852        }
 853
 854        flags = fcntl(sockfd, F_GETFD, 0);
 855        if (flags >= 0)
 856                fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 857
 858        *socklist_p = xmalloc(sizeof(int));
 859        **socklist_p = sockfd;
 860        return 1;
 861}
 862
 863#endif
 864
 865static int service_loop(int socknum, int *socklist)
 866{
 867        struct pollfd *pfd;
 868        int i;
 869
 870        pfd = xcalloc(socknum, sizeof(struct pollfd));
 871
 872        for (i = 0; i < socknum; i++) {
 873                pfd[i].fd = socklist[i];
 874                pfd[i].events = POLLIN;
 875        }
 876
 877        signal(SIGCHLD, child_handler);
 878
 879        for (;;) {
 880                int i;
 881
 882                check_dead_children();
 883
 884                if (poll(pfd, socknum, -1) < 0) {
 885                        if (errno != EINTR) {
 886                                logerror("Poll failed, resuming: %s",
 887                                      strerror(errno));
 888                                sleep(1);
 889                        }
 890                        continue;
 891                }
 892
 893                for (i = 0; i < socknum; i++) {
 894                        if (pfd[i].revents & POLLIN) {
 895                                struct sockaddr_storage ss;
 896                                unsigned int sslen = sizeof(ss);
 897                                int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
 898                                if (incoming < 0) {
 899                                        switch (errno) {
 900                                        case EAGAIN:
 901                                        case EINTR:
 902                                        case ECONNABORTED:
 903                                                continue;
 904                                        default:
 905                                                die_errno("accept returned");
 906                                        }
 907                                }
 908                                handle(incoming, (struct sockaddr *)&ss, sslen);
 909                        }
 910                }
 911        }
 912}
 913
 914/* if any standard file descriptor is missing open it to /dev/null */
 915static void sanitize_stdfds(void)
 916{
 917        int fd = open("/dev/null", O_RDWR, 0);
 918        while (fd != -1 && fd < 2)
 919                fd = dup(fd);
 920        if (fd == -1)
 921                die_errno("open /dev/null or dup failed");
 922        if (fd > 2)
 923                close(fd);
 924}
 925
 926static void daemonize(void)
 927{
 928        switch (fork()) {
 929                case 0:
 930                        break;
 931                case -1:
 932                        die_errno("fork failed");
 933                default:
 934                        exit(0);
 935        }
 936        if (setsid() == -1)
 937                die_errno("setsid failed");
 938        close(0);
 939        close(1);
 940        close(2);
 941        sanitize_stdfds();
 942}
 943
 944static void store_pid(const char *path)
 945{
 946        FILE *f = fopen(path, "w");
 947        if (!f)
 948                die_errno("cannot open pid file '%s'", path);
 949        if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
 950                die_errno("failed to write pid file '%s'", path);
 951}
 952
 953static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
 954{
 955        int socknum, *socklist;
 956
 957        socknum = socksetup(listen_addr, listen_port, &socklist);
 958        if (socknum == 0)
 959                die("unable to allocate any listen sockets on host %s port %u",
 960                    listen_addr, listen_port);
 961
 962        if (pass && gid &&
 963            (initgroups(pass->pw_name, gid) || setgid (gid) ||
 964             setuid(pass->pw_uid)))
 965                die("cannot drop privileges");
 966
 967        return service_loop(socknum, socklist);
 968}
 969
 970int main(int argc, char **argv)
 971{
 972        int listen_port = 0;
 973        char *listen_addr = NULL;
 974        int inetd_mode = 0;
 975        const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
 976        int detach = 0;
 977        struct passwd *pass = NULL;
 978        struct group *group;
 979        gid_t gid = 0;
 980        int i;
 981
 982        git_extract_argv0_path(argv[0]);
 983
 984        for (i = 1; i < argc; i++) {
 985                char *arg = argv[i];
 986
 987                if (!prefixcmp(arg, "--listen=")) {
 988                        listen_addr = xstrdup_tolower(arg + 9);
 989                        continue;
 990                }
 991                if (!prefixcmp(arg, "--port=")) {
 992                        char *end;
 993                        unsigned long n;
 994                        n = strtoul(arg+7, &end, 0);
 995                        if (arg[7] && !*end) {
 996                                listen_port = n;
 997                                continue;
 998                        }
 999                }
1000                if (!strcmp(arg, "--inetd")) {
1001                        inetd_mode = 1;
1002                        log_syslog = 1;
1003                        continue;
1004                }
1005                if (!strcmp(arg, "--verbose")) {
1006                        verbose = 1;
1007                        continue;
1008                }
1009                if (!strcmp(arg, "--syslog")) {
1010                        log_syslog = 1;
1011                        continue;
1012                }
1013                if (!strcmp(arg, "--export-all")) {
1014                        export_all_trees = 1;
1015                        continue;
1016                }
1017                if (!prefixcmp(arg, "--timeout=")) {
1018                        timeout = atoi(arg+10);
1019                        continue;
1020                }
1021                if (!prefixcmp(arg, "--init-timeout=")) {
1022                        init_timeout = atoi(arg+15);
1023                        continue;
1024                }
1025                if (!prefixcmp(arg, "--max-connections=")) {
1026                        max_connections = atoi(arg+18);
1027                        if (max_connections < 0)
1028                                max_connections = 0;            /* unlimited */
1029                        continue;
1030                }
1031                if (!strcmp(arg, "--strict-paths")) {
1032                        strict_paths = 1;
1033                        continue;
1034                }
1035                if (!prefixcmp(arg, "--base-path=")) {
1036                        base_path = arg+12;
1037                        continue;
1038                }
1039                if (!strcmp(arg, "--base-path-relaxed")) {
1040                        base_path_relaxed = 1;
1041                        continue;
1042                }
1043                if (!prefixcmp(arg, "--interpolated-path=")) {
1044                        interpolated_path = arg+20;
1045                        continue;
1046                }
1047                if (!strcmp(arg, "--reuseaddr")) {
1048                        reuseaddr = 1;
1049                        continue;
1050                }
1051                if (!strcmp(arg, "--user-path")) {
1052                        user_path = "";
1053                        continue;
1054                }
1055                if (!prefixcmp(arg, "--user-path=")) {
1056                        user_path = arg + 12;
1057                        continue;
1058                }
1059                if (!prefixcmp(arg, "--pid-file=")) {
1060                        pid_file = arg + 11;
1061                        continue;
1062                }
1063                if (!strcmp(arg, "--detach")) {
1064                        detach = 1;
1065                        log_syslog = 1;
1066                        continue;
1067                }
1068                if (!prefixcmp(arg, "--user=")) {
1069                        user_name = arg + 7;
1070                        continue;
1071                }
1072                if (!prefixcmp(arg, "--group=")) {
1073                        group_name = arg + 8;
1074                        continue;
1075                }
1076                if (!prefixcmp(arg, "--enable=")) {
1077                        enable_service(arg + 9, 1);
1078                        continue;
1079                }
1080                if (!prefixcmp(arg, "--disable=")) {
1081                        enable_service(arg + 10, 0);
1082                        continue;
1083                }
1084                if (!prefixcmp(arg, "--allow-override=")) {
1085                        make_service_overridable(arg + 17, 1);
1086                        continue;
1087                }
1088                if (!prefixcmp(arg, "--forbid-override=")) {
1089                        make_service_overridable(arg + 18, 0);
1090                        continue;
1091                }
1092                if (!strcmp(arg, "--")) {
1093                        ok_paths = &argv[i+1];
1094                        break;
1095                } else if (arg[0] != '-') {
1096                        ok_paths = &argv[i];
1097                        break;
1098                }
1099
1100                usage(daemon_usage);
1101        }
1102
1103        if (log_syslog) {
1104                openlog("git-daemon", LOG_PID, LOG_DAEMON);
1105                set_die_routine(daemon_die);
1106        } else
1107                /* avoid splitting a message in the middle */
1108                setvbuf(stderr, NULL, _IOLBF, 0);
1109
1110        if (inetd_mode && (group_name || user_name))
1111                die("--user and --group are incompatible with --inetd");
1112
1113        if (inetd_mode && (listen_port || listen_addr))
1114                die("--listen= and --port= are incompatible with --inetd");
1115        else if (listen_port == 0)
1116                listen_port = DEFAULT_GIT_PORT;
1117
1118        if (group_name && !user_name)
1119                die("--group supplied without --user");
1120
1121        if (user_name) {
1122                pass = getpwnam(user_name);
1123                if (!pass)
1124                        die("user not found - %s", user_name);
1125
1126                if (!group_name)
1127                        gid = pass->pw_gid;
1128                else {
1129                        group = getgrnam(group_name);
1130                        if (!group)
1131                                die("group not found - %s", group_name);
1132
1133                        gid = group->gr_gid;
1134                }
1135        }
1136
1137        if (strict_paths && (!ok_paths || !*ok_paths))
1138                die("option --strict-paths requires a whitelist");
1139
1140        if (base_path && !is_directory(base_path))
1141                die("base-path '%s' does not exist or is not a directory",
1142                    base_path);
1143
1144        if (inetd_mode) {
1145                struct sockaddr_storage ss;
1146                struct sockaddr *peer = (struct sockaddr *)&ss;
1147                socklen_t slen = sizeof(ss);
1148
1149                if (!freopen("/dev/null", "w", stderr))
1150                        die_errno("failed to redirect stderr to /dev/null");
1151
1152                if (getpeername(0, peer, &slen))
1153                        peer = NULL;
1154
1155                return execute(peer);
1156        }
1157
1158        if (detach) {
1159                daemonize();
1160                loginfo("Ready to rumble");
1161        }
1162        else
1163                sanitize_stdfds();
1164
1165        if (pid_file)
1166                store_pid(pid_file);
1167
1168        return serve(listen_addr, listen_port, pass, gid);
1169}