Andrew's git / gitweb.git / daemon.c
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daemon.con commit Support addresses with ':' in git-daemon (e8dbd76)
   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
 448static void parse_host_and_port(char *hostport, char **host,
 449        char **port)
 450{
 451        if (*hostport == '[') {
 452                char *end;
 453
 454                end = strchr(hostport, ']');
 455                if (!end)
 456                        die("Invalid reqeuest ('[' without ']')");
 457                *end = '\0';
 458                *host = hostport + 1;
 459                if (!end[1])
 460                        *port = NULL;
 461                else if (end[1] == ':')
 462                        *port = end + 2;
 463                else
 464                        die("Garbage after end of host part");
 465        } else {
 466                *host = hostport;
 467                *port = strrchr(hostport, ':');
 468                if (*port) {
 469                        *port = '\0';
 470                        ++*port;
 471                }
 472        }
 473}
 474
 475/*
 476 * Read the host as supplied by the client connection.
 477 */
 478static void parse_host_arg(char *extra_args, int buflen)
 479{
 480        char *val;
 481        int vallen;
 482        char *end = extra_args + buflen;
 483
 484        if (extra_args < end && *extra_args) {
 485                saw_extended_args = 1;
 486                if (strncasecmp("host=", extra_args, 5) == 0) {
 487                        val = extra_args + 5;
 488                        vallen = strlen(val) + 1;
 489                        if (*val) {
 490                                /* Split <host>:<port> at colon. */
 491                                char *host;
 492                                char *port;
 493                                parse_host_and_port(val, &host, &port);
 494                                if (port) {
 495                                        free(tcp_port);
 496                                        tcp_port = xstrdup(port);
 497                                }
 498                                free(hostname);
 499                                hostname = xstrdup_tolower(host);
 500                        }
 501
 502                        /* On to the next one */
 503                        extra_args = val + vallen;
 504                }
 505                if (extra_args < end && *extra_args)
 506                        die("Invalid request");
 507        }
 508
 509        /*
 510         * Locate canonical hostname and its IP address.
 511         */
 512        if (hostname) {
 513#ifndef NO_IPV6
 514                struct addrinfo hints;
 515                struct addrinfo *ai;
 516                int gai;
 517                static char addrbuf[HOST_NAME_MAX + 1];
 518
 519                memset(&hints, 0, sizeof(hints));
 520                hints.ai_flags = AI_CANONNAME;
 521
 522                gai = getaddrinfo(hostname, NULL, &hints, &ai);
 523                if (!gai) {
 524                        struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 525
 526                        inet_ntop(AF_INET, &sin_addr->sin_addr,
 527                                  addrbuf, sizeof(addrbuf));
 528                        free(ip_address);
 529                        ip_address = xstrdup(addrbuf);
 530
 531                        free(canon_hostname);
 532                        canon_hostname = xstrdup(ai->ai_canonname ?
 533                                                 ai->ai_canonname : ip_address);
 534
 535                        freeaddrinfo(ai);
 536                }
 537#else
 538                struct hostent *hent;
 539                struct sockaddr_in sa;
 540                char **ap;
 541                static char addrbuf[HOST_NAME_MAX + 1];
 542
 543                hent = gethostbyname(hostname);
 544
 545                ap = hent->h_addr_list;
 546                memset(&sa, 0, sizeof sa);
 547                sa.sin_family = hent->h_addrtype;
 548                sa.sin_port = htons(0);
 549                memcpy(&sa.sin_addr, *ap, hent->h_length);
 550
 551                inet_ntop(hent->h_addrtype, &sa.sin_addr,
 552                          addrbuf, sizeof(addrbuf));
 553
 554                free(canon_hostname);
 555                canon_hostname = xstrdup(hent->h_name);
 556                free(ip_address);
 557                ip_address = xstrdup(addrbuf);
 558#endif
 559        }
 560}
 561
 562
 563static int execute(struct sockaddr *addr)
 564{
 565        static char line[1000];
 566        int pktlen, len, i;
 567
 568        if (addr) {
 569                char addrbuf[256] = "";
 570                int port = -1;
 571
 572                if (addr->sa_family == AF_INET) {
 573                        struct sockaddr_in *sin_addr = (void *) addr;
 574                        inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
 575                        port = ntohs(sin_addr->sin_port);
 576#ifndef NO_IPV6
 577                } else if (addr && addr->sa_family == AF_INET6) {
 578                        struct sockaddr_in6 *sin6_addr = (void *) addr;
 579
 580                        char *buf = addrbuf;
 581                        *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 582                        inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
 583                        strcat(buf, "]");
 584
 585                        port = ntohs(sin6_addr->sin6_port);
 586#endif
 587                }
 588                loginfo("Connection from %s:%d", addrbuf, port);
 589                setenv("REMOTE_ADDR", addrbuf, 1);
 590        }
 591        else {
 592                unsetenv("REMOTE_ADDR");
 593        }
 594
 595        alarm(init_timeout ? init_timeout : timeout);
 596        pktlen = packet_read_line(0, line, sizeof(line));
 597        alarm(0);
 598
 599        len = strlen(line);
 600        if (pktlen != len)
 601                loginfo("Extended attributes (%d bytes) exist <%.*s>",
 602                        (int) pktlen - len,
 603                        (int) pktlen - len, line + len + 1);
 604        if (len && line[len-1] == '\n') {
 605                line[--len] = 0;
 606                pktlen--;
 607        }
 608
 609        free(hostname);
 610        free(canon_hostname);
 611        free(ip_address);
 612        free(tcp_port);
 613        hostname = canon_hostname = ip_address = tcp_port = NULL;
 614
 615        if (len != pktlen)
 616                parse_host_arg(line + len + 1, pktlen - len - 1);
 617
 618        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 619                struct daemon_service *s = &(daemon_service[i]);
 620                int namelen = strlen(s->name);
 621                if (!prefixcmp(line, "git-") &&
 622                    !strncmp(s->name, line + 4, namelen) &&
 623                    line[namelen + 4] == ' ') {
 624                        /*
 625                         * Note: The directory here is probably context sensitive,
 626                         * and might depend on the actual service being performed.
 627                         */
 628                        return run_service(line + namelen + 5, s);
 629                }
 630        }
 631
 632        logerror("Protocol error: '%s'", line);
 633        return -1;
 634}
 635
 636static int max_connections = 32;
 637
 638static unsigned int live_children;
 639
 640static struct child {
 641        struct child *next;
 642        pid_t pid;
 643        struct sockaddr_storage address;
 644} *firstborn;
 645
 646static void add_child(pid_t pid, struct sockaddr *addr, int addrlen)
 647{
 648        struct child *newborn, **cradle;
 649
 650        /*
 651         * This must be xcalloc() -- we'll compare the whole sockaddr_storage
 652         * but individual address may be shorter.
 653         */
 654        newborn = xcalloc(1, sizeof(*newborn));
 655        live_children++;
 656        newborn->pid = pid;
 657        memcpy(&newborn->address, addr, addrlen);
 658        for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 659                if (!memcmp(&(*cradle)->address, &newborn->address,
 660                            sizeof(newborn->address)))
 661                        break;
 662        newborn->next = *cradle;
 663        *cradle = newborn;
 664}
 665
 666static void remove_child(pid_t pid)
 667{
 668        struct child **cradle, *blanket;
 669
 670        for (cradle = &firstborn; (blanket = *cradle); cradle = &blanket->next)
 671                if (blanket->pid == pid) {
 672                        *cradle = blanket->next;
 673                        live_children--;
 674                        free(blanket);
 675                        break;
 676                }
 677}
 678
 679/*
 680 * This gets called if the number of connections grows
 681 * past "max_connections".
 682 *
 683 * We kill the newest connection from a duplicate IP.
 684 */
 685static void kill_some_child(void)
 686{
 687        const struct child *blanket, *next;
 688
 689        if (!(blanket = firstborn))
 690                return;
 691
 692        for (; (next = blanket->next); blanket = next)
 693                if (!memcmp(&blanket->address, &next->address,
 694                            sizeof(next->address))) {
 695                        kill(blanket->pid, SIGTERM);
 696                        break;
 697                }
 698}
 699
 700static void check_dead_children(void)
 701{
 702        int status;
 703        pid_t pid;
 704
 705        while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
 706                const char *dead = "";
 707                remove_child(pid);
 708                if (!WIFEXITED(status) || (WEXITSTATUS(status) > 0))
 709                        dead = " (with error)";
 710                loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 711        }
 712}
 713
 714static void handle(int incoming, struct sockaddr *addr, int addrlen)
 715{
 716        pid_t pid;
 717
 718        if (max_connections && live_children >= max_connections) {
 719                kill_some_child();
 720                sleep(1);  /* give it some time to die */
 721                check_dead_children();
 722                if (live_children >= max_connections) {
 723                        close(incoming);
 724                        logerror("Too many children, dropping connection");
 725                        return;
 726                }
 727        }
 728
 729        if ((pid = fork())) {
 730                close(incoming);
 731                if (pid < 0) {
 732                        logerror("Couldn't fork %s", strerror(errno));
 733                        return;
 734                }
 735
 736                add_child(pid, addr, addrlen);
 737                return;
 738        }
 739
 740        dup2(incoming, 0);
 741        dup2(incoming, 1);
 742        close(incoming);
 743
 744        exit(execute(addr));
 745}
 746
 747static void child_handler(int signo)
 748{
 749        /*
 750         * Otherwise empty handler because systemcalls will get interrupted
 751         * upon signal receipt
 752         * SysV needs the handler to be rearmed
 753         */
 754        signal(SIGCHLD, child_handler);
 755}
 756
 757static int set_reuse_addr(int sockfd)
 758{
 759        int on = 1;
 760
 761        if (!reuseaddr)
 762                return 0;
 763        return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 764                          &on, sizeof(on));
 765}
 766
 767#ifndef NO_IPV6
 768
 769static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 770{
 771        int socknum = 0, *socklist = NULL;
 772        int maxfd = -1;
 773        char pbuf[NI_MAXSERV];
 774        struct addrinfo hints, *ai0, *ai;
 775        int gai;
 776        long flags;
 777
 778        sprintf(pbuf, "%d", listen_port);
 779        memset(&hints, 0, sizeof(hints));
 780        hints.ai_family = AF_UNSPEC;
 781        hints.ai_socktype = SOCK_STREAM;
 782        hints.ai_protocol = IPPROTO_TCP;
 783        hints.ai_flags = AI_PASSIVE;
 784
 785        gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 786        if (gai)
 787                die("getaddrinfo() failed: %s", gai_strerror(gai));
 788
 789        for (ai = ai0; ai; ai = ai->ai_next) {
 790                int sockfd;
 791
 792                sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 793                if (sockfd < 0)
 794                        continue;
 795                if (sockfd >= FD_SETSIZE) {
 796                        logerror("Socket descriptor too large");
 797                        close(sockfd);
 798                        continue;
 799                }
 800
 801#ifdef IPV6_V6ONLY
 802                if (ai->ai_family == AF_INET6) {
 803                        int on = 1;
 804                        setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 805                                   &on, sizeof(on));
 806                        /* Note: error is not fatal */
 807                }
 808#endif
 809
 810                if (set_reuse_addr(sockfd)) {
 811                        close(sockfd);
 812                        continue;
 813                }
 814
 815                if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 816                        close(sockfd);
 817                        continue;       /* not fatal */
 818                }
 819                if (listen(sockfd, 5) < 0) {
 820                        close(sockfd);
 821                        continue;       /* not fatal */
 822                }
 823
 824                flags = fcntl(sockfd, F_GETFD, 0);
 825                if (flags >= 0)
 826                        fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 827
 828                socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
 829                socklist[socknum++] = sockfd;
 830
 831                if (maxfd < sockfd)
 832                        maxfd = sockfd;
 833        }
 834
 835        freeaddrinfo(ai0);
 836
 837        *socklist_p = socklist;
 838        return socknum;
 839}
 840
 841#else /* NO_IPV6 */
 842
 843static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 844{
 845        struct sockaddr_in sin;
 846        int sockfd;
 847        long flags;
 848
 849        memset(&sin, 0, sizeof sin);
 850        sin.sin_family = AF_INET;
 851        sin.sin_port = htons(listen_port);
 852
 853        if (listen_addr) {
 854                /* Well, host better be an IP address here. */
 855                if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 856                        return 0;
 857        } else {
 858                sin.sin_addr.s_addr = htonl(INADDR_ANY);
 859        }
 860
 861        sockfd = socket(AF_INET, SOCK_STREAM, 0);
 862        if (sockfd < 0)
 863                return 0;
 864
 865        if (set_reuse_addr(sockfd)) {
 866                close(sockfd);
 867                return 0;
 868        }
 869
 870        if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 871                close(sockfd);
 872                return 0;
 873        }
 874
 875        if (listen(sockfd, 5) < 0) {
 876                close(sockfd);
 877                return 0;
 878        }
 879
 880        flags = fcntl(sockfd, F_GETFD, 0);
 881        if (flags >= 0)
 882                fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 883
 884        *socklist_p = xmalloc(sizeof(int));
 885        **socklist_p = sockfd;
 886        return 1;
 887}
 888
 889#endif
 890
 891static int service_loop(int socknum, int *socklist)
 892{
 893        struct pollfd *pfd;
 894        int i;
 895
 896        pfd = xcalloc(socknum, sizeof(struct pollfd));
 897
 898        for (i = 0; i < socknum; i++) {
 899                pfd[i].fd = socklist[i];
 900                pfd[i].events = POLLIN;
 901        }
 902
 903        signal(SIGCHLD, child_handler);
 904
 905        for (;;) {
 906                int i;
 907
 908                check_dead_children();
 909
 910                if (poll(pfd, socknum, -1) < 0) {
 911                        if (errno != EINTR) {
 912                                logerror("Poll failed, resuming: %s",
 913                                      strerror(errno));
 914                                sleep(1);
 915                        }
 916                        continue;
 917                }
 918
 919                for (i = 0; i < socknum; i++) {
 920                        if (pfd[i].revents & POLLIN) {
 921                                struct sockaddr_storage ss;
 922                                unsigned int sslen = sizeof(ss);
 923                                int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
 924                                if (incoming < 0) {
 925                                        switch (errno) {
 926                                        case EAGAIN:
 927                                        case EINTR:
 928                                        case ECONNABORTED:
 929                                                continue;
 930                                        default:
 931                                                die_errno("accept returned");
 932                                        }
 933                                }
 934                                handle(incoming, (struct sockaddr *)&ss, sslen);
 935                        }
 936                }
 937        }
 938}
 939
 940/* if any standard file descriptor is missing open it to /dev/null */
 941static void sanitize_stdfds(void)
 942{
 943        int fd = open("/dev/null", O_RDWR, 0);
 944        while (fd != -1 && fd < 2)
 945                fd = dup(fd);
 946        if (fd == -1)
 947                die_errno("open /dev/null or dup failed");
 948        if (fd > 2)
 949                close(fd);
 950}
 951
 952static void daemonize(void)
 953{
 954        switch (fork()) {
 955                case 0:
 956                        break;
 957                case -1:
 958                        die_errno("fork failed");
 959                default:
 960                        exit(0);
 961        }
 962        if (setsid() == -1)
 963                die_errno("setsid failed");
 964        close(0);
 965        close(1);
 966        close(2);
 967        sanitize_stdfds();
 968}
 969
 970static void store_pid(const char *path)
 971{
 972        FILE *f = fopen(path, "w");
 973        if (!f)
 974                die_errno("cannot open pid file '%s'", path);
 975        if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
 976                die_errno("failed to write pid file '%s'", path);
 977}
 978
 979static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
 980{
 981        int socknum, *socklist;
 982
 983        socknum = socksetup(listen_addr, listen_port, &socklist);
 984        if (socknum == 0)
 985                die("unable to allocate any listen sockets on host %s port %u",
 986                    listen_addr, listen_port);
 987
 988        if (pass && gid &&
 989            (initgroups(pass->pw_name, gid) || setgid (gid) ||
 990             setuid(pass->pw_uid)))
 991                die("cannot drop privileges");
 992
 993        return service_loop(socknum, socklist);
 994}
 995
 996int main(int argc, char **argv)
 997{
 998        int listen_port = 0;
 999        char *listen_addr = NULL;
1000        int inetd_mode = 0;
1001        const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1002        int detach = 0;
1003        struct passwd *pass = NULL;
1004        struct group *group;
1005        gid_t gid = 0;
1006        int i;
1007
1008        git_extract_argv0_path(argv[0]);
1009
1010        for (i = 1; i < argc; i++) {
1011                char *arg = argv[i];
1012
1013                if (!prefixcmp(arg, "--listen=")) {
1014                        listen_addr = xstrdup_tolower(arg + 9);
1015                        continue;
1016                }
1017                if (!prefixcmp(arg, "--port=")) {
1018                        char *end;
1019                        unsigned long n;
1020                        n = strtoul(arg+7, &end, 0);
1021                        if (arg[7] && !*end) {
1022                                listen_port = n;
1023                                continue;
1024                        }
1025                }
1026                if (!strcmp(arg, "--inetd")) {
1027                        inetd_mode = 1;
1028                        log_syslog = 1;
1029                        continue;
1030                }
1031                if (!strcmp(arg, "--verbose")) {
1032                        verbose = 1;
1033                        continue;
1034                }
1035                if (!strcmp(arg, "--syslog")) {
1036                        log_syslog = 1;
1037                        continue;
1038                }
1039                if (!strcmp(arg, "--export-all")) {
1040                        export_all_trees = 1;
1041                        continue;
1042                }
1043                if (!prefixcmp(arg, "--timeout=")) {
1044                        timeout = atoi(arg+10);
1045                        continue;
1046                }
1047                if (!prefixcmp(arg, "--init-timeout=")) {
1048                        init_timeout = atoi(arg+15);
1049                        continue;
1050                }
1051                if (!prefixcmp(arg, "--max-connections=")) {
1052                        max_connections = atoi(arg+18);
1053                        if (max_connections < 0)
1054                                max_connections = 0;            /* unlimited */
1055                        continue;
1056                }
1057                if (!strcmp(arg, "--strict-paths")) {
1058                        strict_paths = 1;
1059                        continue;
1060                }
1061                if (!prefixcmp(arg, "--base-path=")) {
1062                        base_path = arg+12;
1063                        continue;
1064                }
1065                if (!strcmp(arg, "--base-path-relaxed")) {
1066                        base_path_relaxed = 1;
1067                        continue;
1068                }
1069                if (!prefixcmp(arg, "--interpolated-path=")) {
1070                        interpolated_path = arg+20;
1071                        continue;
1072                }
1073                if (!strcmp(arg, "--reuseaddr")) {
1074                        reuseaddr = 1;
1075                        continue;
1076                }
1077                if (!strcmp(arg, "--user-path")) {
1078                        user_path = "";
1079                        continue;
1080                }
1081                if (!prefixcmp(arg, "--user-path=")) {
1082                        user_path = arg + 12;
1083                        continue;
1084                }
1085                if (!prefixcmp(arg, "--pid-file=")) {
1086                        pid_file = arg + 11;
1087                        continue;
1088                }
1089                if (!strcmp(arg, "--detach")) {
1090                        detach = 1;
1091                        log_syslog = 1;
1092                        continue;
1093                }
1094                if (!prefixcmp(arg, "--user=")) {
1095                        user_name = arg + 7;
1096                        continue;
1097                }
1098                if (!prefixcmp(arg, "--group=")) {
1099                        group_name = arg + 8;
1100                        continue;
1101                }
1102                if (!prefixcmp(arg, "--enable=")) {
1103                        enable_service(arg + 9, 1);
1104                        continue;
1105                }
1106                if (!prefixcmp(arg, "--disable=")) {
1107                        enable_service(arg + 10, 0);
1108                        continue;
1109                }
1110                if (!prefixcmp(arg, "--allow-override=")) {
1111                        make_service_overridable(arg + 17, 1);
1112                        continue;
1113                }
1114                if (!prefixcmp(arg, "--forbid-override=")) {
1115                        make_service_overridable(arg + 18, 0);
1116                        continue;
1117                }
1118                if (!strcmp(arg, "--")) {
1119                        ok_paths = &argv[i+1];
1120                        break;
1121                } else if (arg[0] != '-') {
1122                        ok_paths = &argv[i];
1123                        break;
1124                }
1125
1126                usage(daemon_usage);
1127        }
1128
1129        if (log_syslog) {
1130                openlog("git-daemon", LOG_PID, LOG_DAEMON);
1131                set_die_routine(daemon_die);
1132        } else
1133                /* avoid splitting a message in the middle */
1134                setvbuf(stderr, NULL, _IOLBF, 0);
1135
1136        if (inetd_mode && (group_name || user_name))
1137                die("--user and --group are incompatible with --inetd");
1138
1139        if (inetd_mode && (listen_port || listen_addr))
1140                die("--listen= and --port= are incompatible with --inetd");
1141        else if (listen_port == 0)
1142                listen_port = DEFAULT_GIT_PORT;
1143
1144        if (group_name && !user_name)
1145                die("--group supplied without --user");
1146
1147        if (user_name) {
1148                pass = getpwnam(user_name);
1149                if (!pass)
1150                        die("user not found - %s", user_name);
1151
1152                if (!group_name)
1153                        gid = pass->pw_gid;
1154                else {
1155                        group = getgrnam(group_name);
1156                        if (!group)
1157                                die("group not found - %s", group_name);
1158
1159                        gid = group->gr_gid;
1160                }
1161        }
1162
1163        if (strict_paths && (!ok_paths || !*ok_paths))
1164                die("option --strict-paths requires a whitelist");
1165
1166        if (base_path && !is_directory(base_path))
1167                die("base-path '%s' does not exist or is not a directory",
1168                    base_path);
1169
1170        if (inetd_mode) {
1171                struct sockaddr_storage ss;
1172                struct sockaddr *peer = (struct sockaddr *)&ss;
1173                socklen_t slen = sizeof(ss);
1174
1175                if (!freopen("/dev/null", "w", stderr))
1176                        die_errno("failed to redirect stderr to /dev/null");
1177
1178                if (getpeername(0, peer, &slen))
1179                        peer = NULL;
1180
1181                return execute(peer);
1182        }
1183
1184        if (detach) {
1185                daemonize();
1186                loginfo("Ready to rumble");
1187        }
1188        else
1189                sanitize_stdfds();
1190
1191        if (pid_file)
1192                store_pid(pid_file);
1193
1194        return serve(listen_addr, listen_port, pass, gid);
1195}