Andrew's git / gitweb.git / daemon.c
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daemon.con commit bisect: use new "struct argv_array" to prepare argv for "setup_revisions" (1c953a1)
   1#include "cache.h"
   2#include "pkt-line.h"
   3#include "exec_cmd.h"
   4
   5#include <syslog.h>
   6
   7#ifndef HOST_NAME_MAX
   8#define HOST_NAME_MAX 256
   9#endif
  10
  11#ifndef NI_MAXSERV
  12#define NI_MAXSERV 32
  13#endif
  14
  15static int log_syslog;
  16static int verbose;
  17static int reuseaddr;
  18
  19static const char daemon_usage[] =
  20"git daemon [--verbose] [--syslog] [--export-all]\n"
  21"           [--timeout=n] [--init-timeout=n] [--max-connections=n]\n"
  22"           [--strict-paths] [--base-path=path] [--base-path-relaxed]\n"
  23"           [--user-path | --user-path=path]\n"
  24"           [--interpolated-path=path]\n"
  25"           [--reuseaddr] [--detach] [--pid-file=file]\n"
  26"           [--[enable|disable|allow-override|forbid-override]=service]\n"
  27"           [--inetd | [--listen=host_or_ipaddr] [--port=n]\n"
  28"                      [--user=user [--group=group]]\n"
  29"           [directory...]";
  30
  31/* List of acceptable pathname prefixes */
  32static char **ok_paths;
  33static int strict_paths;
  34
  35/* If this is set, git-daemon-export-ok is not required */
  36static int export_all_trees;
  37
  38/* Take all paths relative to this one if non-NULL */
  39static char *base_path;
  40static char *interpolated_path;
  41static int base_path_relaxed;
  42
  43/* Flag indicating client sent extra args. */
  44static int saw_extended_args;
  45
  46/* If defined, ~user notation is allowed and the string is inserted
  47 * after ~user/.  E.g. a request to git://host/~alice/frotz would
  48 * go to /home/alice/pub_git/frotz with --user-path=pub_git.
  49 */
  50static const char *user_path;
  51
  52/* Timeout, and initial timeout */
  53static unsigned int timeout;
  54static unsigned int init_timeout;
  55
  56static char *hostname;
  57static char *canon_hostname;
  58static char *ip_address;
  59static char *tcp_port;
  60
  61static void logreport(int priority, const char *err, va_list params)
  62{
  63        if (log_syslog) {
  64                char buf[1024];
  65                vsnprintf(buf, sizeof(buf), err, params);
  66                syslog(priority, "%s", buf);
  67        } else {
  68                /*
  69                 * Since stderr is set to linebuffered mode, the
  70                 * logging of different processes will not overlap
  71                 */
  72                fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
  73                vfprintf(stderr, err, params);
  74                fputc('\n', stderr);
  75        }
  76}
  77
  78static void logerror(const char *err, ...)
  79{
  80        va_list params;
  81        va_start(params, err);
  82        logreport(LOG_ERR, err, params);
  83        va_end(params);
  84}
  85
  86static void loginfo(const char *err, ...)
  87{
  88        va_list params;
  89        if (!verbose)
  90                return;
  91        va_start(params, err);
  92        logreport(LOG_INFO, err, params);
  93        va_end(params);
  94}
  95
  96static void NORETURN daemon_die(const char *err, va_list params)
  97{
  98        logreport(LOG_ERR, err, params);
  99        exit(1);
 100}
 101
 102static int avoid_alias(char *p)
 103{
 104        int sl, ndot;
 105
 106        /*
 107         * This resurrects the belts and suspenders paranoia check by HPA
 108         * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
 109         * does not do getcwd() based path canonicalizations.
 110         *
 111         * sl becomes true immediately after seeing '/' and continues to
 112         * be true as long as dots continue after that without intervening
 113         * non-dot character.
 114         */
 115        if (!p || (*p != '/' && *p != '~'))
 116                return -1;
 117        sl = 1; ndot = 0;
 118        p++;
 119
 120        while (1) {
 121                char ch = *p++;
 122                if (sl) {
 123                        if (ch == '.')
 124                                ndot++;
 125                        else if (ch == '/') {
 126                                if (ndot < 3)
 127                                        /* reject //, /./ and /../ */
 128                                        return -1;
 129                                ndot = 0;
 130                        }
 131                        else if (ch == 0) {
 132                                if (0 < ndot && ndot < 3)
 133                                        /* reject /.$ and /..$ */
 134                                        return -1;
 135                                return 0;
 136                        }
 137                        else
 138                                sl = ndot = 0;
 139                }
 140                else if (ch == 0)
 141                        return 0;
 142                else if (ch == '/') {
 143                        sl = 1;
 144                        ndot = 0;
 145                }
 146        }
 147}
 148
 149static char *path_ok(char *directory)
 150{
 151        static char rpath[PATH_MAX];
 152        static char interp_path[PATH_MAX];
 153        char *path;
 154        char *dir;
 155
 156        dir = directory;
 157
 158        if (avoid_alias(dir)) {
 159                logerror("'%s': aliased", dir);
 160                return NULL;
 161        }
 162
 163        if (*dir == '~') {
 164                if (!user_path) {
 165                        logerror("'%s': User-path not allowed", dir);
 166                        return NULL;
 167                }
 168                if (*user_path) {
 169                        /* Got either "~alice" or "~alice/foo";
 170                         * rewrite them to "~alice/%s" or
 171                         * "~alice/%s/foo".
 172                         */
 173                        int namlen, restlen = strlen(dir);
 174                        char *slash = strchr(dir, '/');
 175                        if (!slash)
 176                                slash = dir + restlen;
 177                        namlen = slash - dir;
 178                        restlen -= namlen;
 179                        loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
 180                        snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
 181                                 namlen, dir, user_path, restlen, slash);
 182                        dir = rpath;
 183                }
 184        }
 185        else if (interpolated_path && saw_extended_args) {
 186                struct strbuf expanded_path = STRBUF_INIT;
 187                struct strbuf_expand_dict_entry dict[] = {
 188                        { "H", hostname },
 189                        { "CH", canon_hostname },
 190                        { "IP", ip_address },
 191                        { "P", tcp_port },
 192                        { "D", directory },
 193                        { "%", "%" },
 194                        { NULL }
 195                };
 196
 197                if (*dir != '/') {
 198                        /* Allow only absolute */
 199                        logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 200                        return NULL;
 201                }
 202
 203                strbuf_expand(&expanded_path, interpolated_path,
 204                                strbuf_expand_dict_cb, &dict);
 205                strlcpy(interp_path, expanded_path.buf, PATH_MAX);
 206                strbuf_release(&expanded_path);
 207                loginfo("Interpolated dir '%s'", interp_path);
 208
 209                dir = interp_path;
 210        }
 211        else if (base_path) {
 212                if (*dir != '/') {
 213                        /* Allow only absolute */
 214                        logerror("'%s': Non-absolute path denied (base-path active)", dir);
 215                        return NULL;
 216                }
 217                snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
 218                dir = rpath;
 219        }
 220
 221        path = enter_repo(dir, strict_paths);
 222        if (!path && base_path && base_path_relaxed) {
 223                /*
 224                 * if we fail and base_path_relaxed is enabled, try without
 225                 * prefixing the base path
 226                 */
 227                dir = directory;
 228                path = enter_repo(dir, strict_paths);
 229        }
 230
 231        if (!path) {
 232                logerror("'%s' does not appear to be a git repository", dir);
 233                return NULL;
 234        }
 235
 236        if ( ok_paths && *ok_paths ) {
 237                char **pp;
 238                int pathlen = strlen(path);
 239
 240                /* The validation is done on the paths after enter_repo
 241                 * appends optional {.git,.git/.git} and friends, but
 242                 * it does not use getcwd().  So if your /pub is
 243                 * a symlink to /mnt/pub, you can whitelist /pub and
 244                 * do not have to say /mnt/pub.
 245                 * Do not say /pub/.
 246                 */
 247                for ( pp = ok_paths ; *pp ; pp++ ) {
 248                        int len = strlen(*pp);
 249                        if (len <= pathlen &&
 250                            !memcmp(*pp, path, len) &&
 251                            (path[len] == '\0' ||
 252                             (!strict_paths && path[len] == '/')))
 253                                return path;
 254                }
 255        }
 256        else {
 257                /* be backwards compatible */
 258                if (!strict_paths)
 259                        return path;
 260        }
 261
 262        logerror("'%s': not in whitelist", path);
 263        return NULL;            /* Fallthrough. Deny by default */
 264}
 265
 266typedef int (*daemon_service_fn)(void);
 267struct daemon_service {
 268        const char *name;
 269        const char *config_name;
 270        daemon_service_fn fn;
 271        int enabled;
 272        int overridable;
 273};
 274
 275static struct daemon_service *service_looking_at;
 276static int service_enabled;
 277
 278static int git_daemon_config(const char *var, const char *value, void *cb)
 279{
 280        if (!prefixcmp(var, "daemon.") &&
 281            !strcmp(var + 7, service_looking_at->config_name)) {
 282                service_enabled = git_config_bool(var, value);
 283                return 0;
 284        }
 285
 286        /* we are not interested in parsing any other configuration here */
 287        return 0;
 288}
 289
 290static int run_service(char *dir, struct daemon_service *service)
 291{
 292        const char *path;
 293        int enabled = service->enabled;
 294
 295        loginfo("Request %s for '%s'", service->name, dir);
 296
 297        if (!enabled && !service->overridable) {
 298                logerror("'%s': service not enabled.", service->name);
 299                errno = EACCES;
 300                return -1;
 301        }
 302
 303        if (!(path = path_ok(dir)))
 304                return -1;
 305
 306        /*
 307         * Security on the cheap.
 308         *
 309         * We want a readable HEAD, usable "objects" directory, and
 310         * a "git-daemon-export-ok" flag that says that the other side
 311         * is ok with us doing this.
 312         *
 313         * path_ok() uses enter_repo() and does whitelist checking.
 314         * We only need to make sure the repository is exported.
 315         */
 316
 317        if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 318                logerror("'%s': repository not exported.", path);
 319                errno = EACCES;
 320                return -1;
 321        }
 322
 323        if (service->overridable) {
 324                service_looking_at = service;
 325                service_enabled = -1;
 326                git_config(git_daemon_config, NULL);
 327                if (0 <= service_enabled)
 328                        enabled = service_enabled;
 329        }
 330        if (!enabled) {
 331                logerror("'%s': service not enabled for '%s'",
 332                         service->name, path);
 333                errno = EACCES;
 334                return -1;
 335        }
 336
 337        /*
 338         * We'll ignore SIGTERM from now on, we have a
 339         * good client.
 340         */
 341        signal(SIGTERM, SIG_IGN);
 342
 343        return service->fn();
 344}
 345
 346static int upload_pack(void)
 347{
 348        /* Timeout as string */
 349        char timeout_buf[64];
 350
 351        snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 352
 353        /* git-upload-pack only ever reads stuff, so this is safe */
 354        execl_git_cmd("upload-pack", "--strict", timeout_buf, ".", NULL);
 355        return -1;
 356}
 357
 358static int upload_archive(void)
 359{
 360        execl_git_cmd("upload-archive", ".", NULL);
 361        return -1;
 362}
 363
 364static int receive_pack(void)
 365{
 366        execl_git_cmd("receive-pack", ".", NULL);
 367        return -1;
 368}
 369
 370static struct daemon_service daemon_service[] = {
 371        { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 372        { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 373        { "receive-pack", "receivepack", receive_pack, 0, 1 },
 374};
 375
 376static void enable_service(const char *name, int ena)
 377{
 378        int i;
 379        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 380                if (!strcmp(daemon_service[i].name, name)) {
 381                        daemon_service[i].enabled = ena;
 382                        return;
 383                }
 384        }
 385        die("No such service %s", name);
 386}
 387
 388static void make_service_overridable(const char *name, int ena)
 389{
 390        int i;
 391        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 392                if (!strcmp(daemon_service[i].name, name)) {
 393                        daemon_service[i].overridable = ena;
 394                        return;
 395                }
 396        }
 397        die("No such service %s", name);
 398}
 399
 400static char *xstrdup_tolower(const char *str)
 401{
 402        char *p, *dup = xstrdup(str);
 403        for (p = dup; *p; p++)
 404                *p = tolower(*p);
 405        return dup;
 406}
 407
 408/*
 409 * Separate the "extra args" information as supplied by the client connection.
 410 */
 411static void parse_extra_args(char *extra_args, int buflen)
 412{
 413        char *val;
 414        int vallen;
 415        char *end = extra_args + buflen;
 416
 417        while (extra_args < end && *extra_args) {
 418                saw_extended_args = 1;
 419                if (strncasecmp("host=", extra_args, 5) == 0) {
 420                        val = extra_args + 5;
 421                        vallen = strlen(val) + 1;
 422                        if (*val) {
 423                                /* Split <host>:<port> at colon. */
 424                                char *host = val;
 425                                char *port = strrchr(host, ':');
 426                                if (port) {
 427                                        *port = 0;
 428                                        port++;
 429                                        free(tcp_port);
 430                                        tcp_port = xstrdup(port);
 431                                }
 432                                free(hostname);
 433                                hostname = xstrdup_tolower(host);
 434                        }
 435
 436                        /* On to the next one */
 437                        extra_args = val + vallen;
 438                }
 439        }
 440
 441        /*
 442         * Locate canonical hostname and its IP address.
 443         */
 444        if (hostname) {
 445#ifndef NO_IPV6
 446                struct addrinfo hints;
 447                struct addrinfo *ai;
 448                int gai;
 449                static char addrbuf[HOST_NAME_MAX + 1];
 450
 451                memset(&hints, 0, sizeof(hints));
 452                hints.ai_flags = AI_CANONNAME;
 453
 454                gai = getaddrinfo(hostname, 0, &hints, &ai);
 455                if (!gai) {
 456                        struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 457
 458                        inet_ntop(AF_INET, &sin_addr->sin_addr,
 459                                  addrbuf, sizeof(addrbuf));
 460                        free(ip_address);
 461                        ip_address = xstrdup(addrbuf);
 462
 463                        free(canon_hostname);
 464                        canon_hostname = xstrdup(ai->ai_canonname ?
 465                                                 ai->ai_canonname : ip_address);
 466
 467                        freeaddrinfo(ai);
 468                }
 469#else
 470                struct hostent *hent;
 471                struct sockaddr_in sa;
 472                char **ap;
 473                static char addrbuf[HOST_NAME_MAX + 1];
 474
 475                hent = gethostbyname(hostname);
 476
 477                ap = hent->h_addr_list;
 478                memset(&sa, 0, sizeof sa);
 479                sa.sin_family = hent->h_addrtype;
 480                sa.sin_port = htons(0);
 481                memcpy(&sa.sin_addr, *ap, hent->h_length);
 482
 483                inet_ntop(hent->h_addrtype, &sa.sin_addr,
 484                          addrbuf, sizeof(addrbuf));
 485
 486                free(canon_hostname);
 487                canon_hostname = xstrdup(hent->h_name);
 488                free(ip_address);
 489                ip_address = xstrdup(addrbuf);
 490#endif
 491        }
 492}
 493
 494
 495static int execute(struct sockaddr *addr)
 496{
 497        static char line[1000];
 498        int pktlen, len, i;
 499
 500        if (addr) {
 501                char addrbuf[256] = "";
 502                int port = -1;
 503
 504                if (addr->sa_family == AF_INET) {
 505                        struct sockaddr_in *sin_addr = (void *) addr;
 506                        inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
 507                        port = ntohs(sin_addr->sin_port);
 508#ifndef NO_IPV6
 509                } else if (addr && addr->sa_family == AF_INET6) {
 510                        struct sockaddr_in6 *sin6_addr = (void *) addr;
 511
 512                        char *buf = addrbuf;
 513                        *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 514                        inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
 515                        strcat(buf, "]");
 516
 517                        port = ntohs(sin6_addr->sin6_port);
 518#endif
 519                }
 520                loginfo("Connection from %s:%d", addrbuf, port);
 521                setenv("REMOTE_ADDR", addrbuf, 1);
 522        }
 523        else {
 524                unsetenv("REMOTE_ADDR");
 525        }
 526
 527        alarm(init_timeout ? init_timeout : timeout);
 528        pktlen = packet_read_line(0, line, sizeof(line));
 529        alarm(0);
 530
 531        len = strlen(line);
 532        if (pktlen != len)
 533                loginfo("Extended attributes (%d bytes) exist <%.*s>",
 534                        (int) pktlen - len,
 535                        (int) pktlen - len, line + len + 1);
 536        if (len && line[len-1] == '\n') {
 537                line[--len] = 0;
 538                pktlen--;
 539        }
 540
 541        free(hostname);
 542        free(canon_hostname);
 543        free(ip_address);
 544        free(tcp_port);
 545        hostname = canon_hostname = ip_address = tcp_port = NULL;
 546
 547        if (len != pktlen)
 548                parse_extra_args(line + len + 1, pktlen - len - 1);
 549
 550        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 551                struct daemon_service *s = &(daemon_service[i]);
 552                int namelen = strlen(s->name);
 553                if (!prefixcmp(line, "git-") &&
 554                    !strncmp(s->name, line + 4, namelen) &&
 555                    line[namelen + 4] == ' ') {
 556                        /*
 557                         * Note: The directory here is probably context sensitive,
 558                         * and might depend on the actual service being performed.
 559                         */
 560                        return run_service(line + namelen + 5, s);
 561                }
 562        }
 563
 564        logerror("Protocol error: '%s'", line);
 565        return -1;
 566}
 567
 568static int max_connections = 32;
 569
 570static unsigned int live_children;
 571
 572static struct child {
 573        struct child *next;
 574        pid_t pid;
 575        struct sockaddr_storage address;
 576} *firstborn;
 577
 578static void add_child(pid_t pid, struct sockaddr *addr, int addrlen)
 579{
 580        struct child *newborn, **cradle;
 581
 582        /*
 583         * This must be xcalloc() -- we'll compare the whole sockaddr_storage
 584         * but individual address may be shorter.
 585         */
 586        newborn = xcalloc(1, sizeof(*newborn));
 587        live_children++;
 588        newborn->pid = pid;
 589        memcpy(&newborn->address, addr, addrlen);
 590        for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 591                if (!memcmp(&(*cradle)->address, &newborn->address,
 592                            sizeof(newborn->address)))
 593                        break;
 594        newborn->next = *cradle;
 595        *cradle = newborn;
 596}
 597
 598static void remove_child(pid_t pid)
 599{
 600        struct child **cradle, *blanket;
 601
 602        for (cradle = &firstborn; (blanket = *cradle); cradle = &blanket->next)
 603                if (blanket->pid == pid) {
 604                        *cradle = blanket->next;
 605                        live_children--;
 606                        free(blanket);
 607                        break;
 608                }
 609}
 610
 611/*
 612 * This gets called if the number of connections grows
 613 * past "max_connections".
 614 *
 615 * We kill the newest connection from a duplicate IP.
 616 */
 617static void kill_some_child(void)
 618{
 619        const struct child *blanket, *next;
 620
 621        if (!(blanket = firstborn))
 622                return;
 623
 624        for (; (next = blanket->next); blanket = next)
 625                if (!memcmp(&blanket->address, &next->address,
 626                            sizeof(next->address))) {
 627                        kill(blanket->pid, SIGTERM);
 628                        break;
 629                }
 630}
 631
 632static void check_dead_children(void)
 633{
 634        int status;
 635        pid_t pid;
 636
 637        while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
 638                const char *dead = "";
 639                remove_child(pid);
 640                if (!WIFEXITED(status) || (WEXITSTATUS(status) > 0))
 641                        dead = " (with error)";
 642                loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 643        }
 644}
 645
 646static void handle(int incoming, struct sockaddr *addr, int addrlen)
 647{
 648        pid_t pid;
 649
 650        if (max_connections && live_children >= max_connections) {
 651                kill_some_child();
 652                sleep(1);  /* give it some time to die */
 653                check_dead_children();
 654                if (live_children >= max_connections) {
 655                        close(incoming);
 656                        logerror("Too many children, dropping connection");
 657                        return;
 658                }
 659        }
 660
 661        if ((pid = fork())) {
 662                close(incoming);
 663                if (pid < 0) {
 664                        logerror("Couldn't fork %s", strerror(errno));
 665                        return;
 666                }
 667
 668                add_child(pid, addr, addrlen);
 669                return;
 670        }
 671
 672        dup2(incoming, 0);
 673        dup2(incoming, 1);
 674        close(incoming);
 675
 676        exit(execute(addr));
 677}
 678
 679static void child_handler(int signo)
 680{
 681        /*
 682         * Otherwise empty handler because systemcalls will get interrupted
 683         * upon signal receipt
 684         * SysV needs the handler to be rearmed
 685         */
 686        signal(SIGCHLD, child_handler);
 687}
 688
 689static int set_reuse_addr(int sockfd)
 690{
 691        int on = 1;
 692
 693        if (!reuseaddr)
 694                return 0;
 695        return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 696                          &on, sizeof(on));
 697}
 698
 699#ifndef NO_IPV6
 700
 701static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 702{
 703        int socknum = 0, *socklist = NULL;
 704        int maxfd = -1;
 705        char pbuf[NI_MAXSERV];
 706        struct addrinfo hints, *ai0, *ai;
 707        int gai;
 708        long flags;
 709
 710        sprintf(pbuf, "%d", listen_port);
 711        memset(&hints, 0, sizeof(hints));
 712        hints.ai_family = AF_UNSPEC;
 713        hints.ai_socktype = SOCK_STREAM;
 714        hints.ai_protocol = IPPROTO_TCP;
 715        hints.ai_flags = AI_PASSIVE;
 716
 717        gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 718        if (gai)
 719                die("getaddrinfo() failed: %s", gai_strerror(gai));
 720
 721        for (ai = ai0; ai; ai = ai->ai_next) {
 722                int sockfd;
 723
 724                sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 725                if (sockfd < 0)
 726                        continue;
 727                if (sockfd >= FD_SETSIZE) {
 728                        logerror("Socket descriptor too large");
 729                        close(sockfd);
 730                        continue;
 731                }
 732
 733#ifdef IPV6_V6ONLY
 734                if (ai->ai_family == AF_INET6) {
 735                        int on = 1;
 736                        setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 737                                   &on, sizeof(on));
 738                        /* Note: error is not fatal */
 739                }
 740#endif
 741
 742                if (set_reuse_addr(sockfd)) {
 743                        close(sockfd);
 744                        continue;
 745                }
 746
 747                if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 748                        close(sockfd);
 749                        continue;       /* not fatal */
 750                }
 751                if (listen(sockfd, 5) < 0) {
 752                        close(sockfd);
 753                        continue;       /* not fatal */
 754                }
 755
 756                flags = fcntl(sockfd, F_GETFD, 0);
 757                if (flags >= 0)
 758                        fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 759
 760                socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
 761                socklist[socknum++] = sockfd;
 762
 763                if (maxfd < sockfd)
 764                        maxfd = sockfd;
 765        }
 766
 767        freeaddrinfo(ai0);
 768
 769        *socklist_p = socklist;
 770        return socknum;
 771}
 772
 773#else /* NO_IPV6 */
 774
 775static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 776{
 777        struct sockaddr_in sin;
 778        int sockfd;
 779        long flags;
 780
 781        memset(&sin, 0, sizeof sin);
 782        sin.sin_family = AF_INET;
 783        sin.sin_port = htons(listen_port);
 784
 785        if (listen_addr) {
 786                /* Well, host better be an IP address here. */
 787                if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 788                        return 0;
 789        } else {
 790                sin.sin_addr.s_addr = htonl(INADDR_ANY);
 791        }
 792
 793        sockfd = socket(AF_INET, SOCK_STREAM, 0);
 794        if (sockfd < 0)
 795                return 0;
 796
 797        if (set_reuse_addr(sockfd)) {
 798                close(sockfd);
 799                return 0;
 800        }
 801
 802        if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 803                close(sockfd);
 804                return 0;
 805        }
 806
 807        if (listen(sockfd, 5) < 0) {
 808                close(sockfd);
 809                return 0;
 810        }
 811
 812        flags = fcntl(sockfd, F_GETFD, 0);
 813        if (flags >= 0)
 814                fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 815
 816        *socklist_p = xmalloc(sizeof(int));
 817        **socklist_p = sockfd;
 818        return 1;
 819}
 820
 821#endif
 822
 823static int service_loop(int socknum, int *socklist)
 824{
 825        struct pollfd *pfd;
 826        int i;
 827
 828        pfd = xcalloc(socknum, sizeof(struct pollfd));
 829
 830        for (i = 0; i < socknum; i++) {
 831                pfd[i].fd = socklist[i];
 832                pfd[i].events = POLLIN;
 833        }
 834
 835        signal(SIGCHLD, child_handler);
 836
 837        for (;;) {
 838                int i;
 839
 840                check_dead_children();
 841
 842                if (poll(pfd, socknum, -1) < 0) {
 843                        if (errno != EINTR) {
 844                                logerror("Poll failed, resuming: %s",
 845                                      strerror(errno));
 846                                sleep(1);
 847                        }
 848                        continue;
 849                }
 850
 851                for (i = 0; i < socknum; i++) {
 852                        if (pfd[i].revents & POLLIN) {
 853                                struct sockaddr_storage ss;
 854                                unsigned int sslen = sizeof(ss);
 855                                int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
 856                                if (incoming < 0) {
 857                                        switch (errno) {
 858                                        case EAGAIN:
 859                                        case EINTR:
 860                                        case ECONNABORTED:
 861                                                continue;
 862                                        default:
 863                                                die("accept returned %s", strerror(errno));
 864                                        }
 865                                }
 866                                handle(incoming, (struct sockaddr *)&ss, sslen);
 867                        }
 868                }
 869        }
 870}
 871
 872/* if any standard file descriptor is missing open it to /dev/null */
 873static void sanitize_stdfds(void)
 874{
 875        int fd = open("/dev/null", O_RDWR, 0);
 876        while (fd != -1 && fd < 2)
 877                fd = dup(fd);
 878        if (fd == -1)
 879                die("open /dev/null or dup failed: %s", strerror(errno));
 880        if (fd > 2)
 881                close(fd);
 882}
 883
 884static void daemonize(void)
 885{
 886        switch (fork()) {
 887                case 0:
 888                        break;
 889                case -1:
 890                        die("fork failed: %s", strerror(errno));
 891                default:
 892                        exit(0);
 893        }
 894        if (setsid() == -1)
 895                die("setsid failed: %s", strerror(errno));
 896        close(0);
 897        close(1);
 898        close(2);
 899        sanitize_stdfds();
 900}
 901
 902static void store_pid(const char *path)
 903{
 904        FILE *f = fopen(path, "w");
 905        if (!f)
 906                die("cannot open pid file %s: %s", path, strerror(errno));
 907        if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
 908                die("failed to write pid file %s: %s", path, strerror(errno));
 909}
 910
 911static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
 912{
 913        int socknum, *socklist;
 914
 915        socknum = socksetup(listen_addr, listen_port, &socklist);
 916        if (socknum == 0)
 917                die("unable to allocate any listen sockets on host %s port %u",
 918                    listen_addr, listen_port);
 919
 920        if (pass && gid &&
 921            (initgroups(pass->pw_name, gid) || setgid (gid) ||
 922             setuid(pass->pw_uid)))
 923                die("cannot drop privileges");
 924
 925        return service_loop(socknum, socklist);
 926}
 927
 928int main(int argc, char **argv)
 929{
 930        int listen_port = 0;
 931        char *listen_addr = NULL;
 932        int inetd_mode = 0;
 933        const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
 934        int detach = 0;
 935        struct passwd *pass = NULL;
 936        struct group *group;
 937        gid_t gid = 0;
 938        int i;
 939
 940        git_extract_argv0_path(argv[0]);
 941
 942        for (i = 1; i < argc; i++) {
 943                char *arg = argv[i];
 944
 945                if (!prefixcmp(arg, "--listen=")) {
 946                        listen_addr = xstrdup_tolower(arg + 9);
 947                        continue;
 948                }
 949                if (!prefixcmp(arg, "--port=")) {
 950                        char *end;
 951                        unsigned long n;
 952                        n = strtoul(arg+7, &end, 0);
 953                        if (arg[7] && !*end) {
 954                                listen_port = n;
 955                                continue;
 956                        }
 957                }
 958                if (!strcmp(arg, "--inetd")) {
 959                        inetd_mode = 1;
 960                        log_syslog = 1;
 961                        continue;
 962                }
 963                if (!strcmp(arg, "--verbose")) {
 964                        verbose = 1;
 965                        continue;
 966                }
 967                if (!strcmp(arg, "--syslog")) {
 968                        log_syslog = 1;
 969                        continue;
 970                }
 971                if (!strcmp(arg, "--export-all")) {
 972                        export_all_trees = 1;
 973                        continue;
 974                }
 975                if (!prefixcmp(arg, "--timeout=")) {
 976                        timeout = atoi(arg+10);
 977                        continue;
 978                }
 979                if (!prefixcmp(arg, "--init-timeout=")) {
 980                        init_timeout = atoi(arg+15);
 981                        continue;
 982                }
 983                if (!prefixcmp(arg, "--max-connections=")) {
 984                        max_connections = atoi(arg+18);
 985                        if (max_connections < 0)
 986                                max_connections = 0;            /* unlimited */
 987                        continue;
 988                }
 989                if (!strcmp(arg, "--strict-paths")) {
 990                        strict_paths = 1;
 991                        continue;
 992                }
 993                if (!prefixcmp(arg, "--base-path=")) {
 994                        base_path = arg+12;
 995                        continue;
 996                }
 997                if (!strcmp(arg, "--base-path-relaxed")) {
 998                        base_path_relaxed = 1;
 999                        continue;
1000                }
1001                if (!prefixcmp(arg, "--interpolated-path=")) {
1002                        interpolated_path = arg+20;
1003                        continue;
1004                }
1005                if (!strcmp(arg, "--reuseaddr")) {
1006                        reuseaddr = 1;
1007                        continue;
1008                }
1009                if (!strcmp(arg, "--user-path")) {
1010                        user_path = "";
1011                        continue;
1012                }
1013                if (!prefixcmp(arg, "--user-path=")) {
1014                        user_path = arg + 12;
1015                        continue;
1016                }
1017                if (!prefixcmp(arg, "--pid-file=")) {
1018                        pid_file = arg + 11;
1019                        continue;
1020                }
1021                if (!strcmp(arg, "--detach")) {
1022                        detach = 1;
1023                        log_syslog = 1;
1024                        continue;
1025                }
1026                if (!prefixcmp(arg, "--user=")) {
1027                        user_name = arg + 7;
1028                        continue;
1029                }
1030                if (!prefixcmp(arg, "--group=")) {
1031                        group_name = arg + 8;
1032                        continue;
1033                }
1034                if (!prefixcmp(arg, "--enable=")) {
1035                        enable_service(arg + 9, 1);
1036                        continue;
1037                }
1038                if (!prefixcmp(arg, "--disable=")) {
1039                        enable_service(arg + 10, 0);
1040                        continue;
1041                }
1042                if (!prefixcmp(arg, "--allow-override=")) {
1043                        make_service_overridable(arg + 17, 1);
1044                        continue;
1045                }
1046                if (!prefixcmp(arg, "--forbid-override=")) {
1047                        make_service_overridable(arg + 18, 0);
1048                        continue;
1049                }
1050                if (!strcmp(arg, "--")) {
1051                        ok_paths = &argv[i+1];
1052                        break;
1053                } else if (arg[0] != '-') {
1054                        ok_paths = &argv[i];
1055                        break;
1056                }
1057
1058                usage(daemon_usage);
1059        }
1060
1061        if (log_syslog) {
1062                openlog("git-daemon", LOG_PID, LOG_DAEMON);
1063                set_die_routine(daemon_die);
1064        } else
1065                /* avoid splitting a message in the middle */
1066                setvbuf(stderr, NULL, _IOLBF, 0);
1067
1068        if (inetd_mode && (group_name || user_name))
1069                die("--user and --group are incompatible with --inetd");
1070
1071        if (inetd_mode && (listen_port || listen_addr))
1072                die("--listen= and --port= are incompatible with --inetd");
1073        else if (listen_port == 0)
1074                listen_port = DEFAULT_GIT_PORT;
1075
1076        if (group_name && !user_name)
1077                die("--group supplied without --user");
1078
1079        if (user_name) {
1080                pass = getpwnam(user_name);
1081                if (!pass)
1082                        die("user not found - %s", user_name);
1083
1084                if (!group_name)
1085                        gid = pass->pw_gid;
1086                else {
1087                        group = getgrnam(group_name);
1088                        if (!group)
1089                                die("group not found - %s", group_name);
1090
1091                        gid = group->gr_gid;
1092                }
1093        }
1094
1095        if (strict_paths && (!ok_paths || !*ok_paths))
1096                die("option --strict-paths requires a whitelist");
1097
1098        if (base_path && !is_directory(base_path))
1099                die("base-path '%s' does not exist or is not a directory",
1100                    base_path);
1101
1102        if (inetd_mode) {
1103                struct sockaddr_storage ss;
1104                struct sockaddr *peer = (struct sockaddr *)&ss;
1105                socklen_t slen = sizeof(ss);
1106
1107                if (!freopen("/dev/null", "w", stderr))
1108                        die("failed to redirect stderr to /dev/null: %s",
1109                            strerror(errno));
1110
1111                if (getpeername(0, peer, &slen))
1112                        peer = NULL;
1113
1114                return execute(peer);
1115        }
1116
1117        if (detach) {
1118                daemonize();
1119                loginfo("Ready to rumble");
1120        }
1121        else
1122                sanitize_stdfds();
1123
1124        if (pid_file)
1125                store_pid(pid_file);
1126
1127        return serve(listen_addr, listen_port, pass, gid);
1128}