daemon.con commit git-sh-setup: Fix scripts whose PWD is a symlink into a git work-dir (08fc060)
   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        int retried_path = 0;
 154        char *path;
 155        char *dir;
 156
 157        dir = directory;
 158
 159        if (avoid_alias(dir)) {
 160                logerror("'%s': aliased", dir);
 161                return NULL;
 162        }
 163
 164        if (*dir == '~') {
 165                if (!user_path) {
 166                        logerror("'%s': User-path not allowed", dir);
 167                        return NULL;
 168                }
 169                if (*user_path) {
 170                        /* Got either "~alice" or "~alice/foo";
 171                         * rewrite them to "~alice/%s" or
 172                         * "~alice/%s/foo".
 173                         */
 174                        int namlen, restlen = strlen(dir);
 175                        char *slash = strchr(dir, '/');
 176                        if (!slash)
 177                                slash = dir + restlen;
 178                        namlen = slash - dir;
 179                        restlen -= namlen;
 180                        loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
 181                        snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
 182                                 namlen, dir, user_path, restlen, slash);
 183                        dir = rpath;
 184                }
 185        }
 186        else if (interpolated_path && saw_extended_args) {
 187                struct strbuf expanded_path = STRBUF_INIT;
 188                struct strbuf_expand_dict_entry dict[] = {
 189                        { "H", hostname },
 190                        { "CH", canon_hostname },
 191                        { "IP", ip_address },
 192                        { "P", tcp_port },
 193                        { "D", directory },
 194                        { "%", "%" },
 195                        { NULL }
 196                };
 197
 198                if (*dir != '/') {
 199                        /* Allow only absolute */
 200                        logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 201                        return NULL;
 202                }
 203
 204                strbuf_expand(&expanded_path, interpolated_path,
 205                                strbuf_expand_dict_cb, &dict);
 206                strlcpy(interp_path, expanded_path.buf, PATH_MAX);
 207                strbuf_release(&expanded_path);
 208                loginfo("Interpolated dir '%s'", interp_path);
 209
 210                dir = interp_path;
 211        }
 212        else if (base_path) {
 213                if (*dir != '/') {
 214                        /* Allow only absolute */
 215                        logerror("'%s': Non-absolute path denied (base-path active)", dir);
 216                        return NULL;
 217                }
 218                snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
 219                dir = rpath;
 220        }
 221
 222        do {
 223                path = enter_repo(dir, strict_paths);
 224                if (path)
 225                        break;
 226
 227                /*
 228                 * if we fail and base_path_relaxed is enabled, try without
 229                 * prefixing the base path
 230                 */
 231                if (base_path && base_path_relaxed && !retried_path) {
 232                        dir = directory;
 233                        retried_path = 1;
 234                        continue;
 235                }
 236                break;
 237        } while (1);
 238
 239        if (!path) {
 240                logerror("'%s': unable to chdir or not a git archive", dir);
 241                return NULL;
 242        }
 243
 244        if ( ok_paths && *ok_paths ) {
 245                char **pp;
 246                int pathlen = strlen(path);
 247
 248                /* The validation is done on the paths after enter_repo
 249                 * appends optional {.git,.git/.git} and friends, but
 250                 * it does not use getcwd().  So if your /pub is
 251                 * a symlink to /mnt/pub, you can whitelist /pub and
 252                 * do not have to say /mnt/pub.
 253                 * Do not say /pub/.
 254                 */
 255                for ( pp = ok_paths ; *pp ; pp++ ) {
 256                        int len = strlen(*pp);
 257                        if (len <= pathlen &&
 258                            !memcmp(*pp, path, len) &&
 259                            (path[len] == '\0' ||
 260                             (!strict_paths && path[len] == '/')))
 261                                return path;
 262                }
 263        }
 264        else {
 265                /* be backwards compatible */
 266                if (!strict_paths)
 267                        return path;
 268        }
 269
 270        logerror("'%s': not in whitelist", path);
 271        return NULL;            /* Fallthrough. Deny by default */
 272}
 273
 274typedef int (*daemon_service_fn)(void);
 275struct daemon_service {
 276        const char *name;
 277        const char *config_name;
 278        daemon_service_fn fn;
 279        int enabled;
 280        int overridable;
 281};
 282
 283static struct daemon_service *service_looking_at;
 284static int service_enabled;
 285
 286static int git_daemon_config(const char *var, const char *value, void *cb)
 287{
 288        if (!prefixcmp(var, "daemon.") &&
 289            !strcmp(var + 7, service_looking_at->config_name)) {
 290                service_enabled = git_config_bool(var, value);
 291                return 0;
 292        }
 293
 294        /* we are not interested in parsing any other configuration here */
 295        return 0;
 296}
 297
 298static int run_service(char *dir, struct daemon_service *service)
 299{
 300        const char *path;
 301        int enabled = service->enabled;
 302
 303        loginfo("Request %s for '%s'", service->name, dir);
 304
 305        if (!enabled && !service->overridable) {
 306                logerror("'%s': service not enabled.", service->name);
 307                errno = EACCES;
 308                return -1;
 309        }
 310
 311        if (!(path = path_ok(dir)))
 312                return -1;
 313
 314        /*
 315         * Security on the cheap.
 316         *
 317         * We want a readable HEAD, usable "objects" directory, and
 318         * a "git-daemon-export-ok" flag that says that the other side
 319         * is ok with us doing this.
 320         *
 321         * path_ok() uses enter_repo() and does whitelist checking.
 322         * We only need to make sure the repository is exported.
 323         */
 324
 325        if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 326                logerror("'%s': repository not exported.", path);
 327                errno = EACCES;
 328                return -1;
 329        }
 330
 331        if (service->overridable) {
 332                service_looking_at = service;
 333                service_enabled = -1;
 334                git_config(git_daemon_config, NULL);
 335                if (0 <= service_enabled)
 336                        enabled = service_enabled;
 337        }
 338        if (!enabled) {
 339                logerror("'%s': service not enabled for '%s'",
 340                         service->name, path);
 341                errno = EACCES;
 342                return -1;
 343        }
 344
 345        /*
 346         * We'll ignore SIGTERM from now on, we have a
 347         * good client.
 348         */
 349        signal(SIGTERM, SIG_IGN);
 350
 351        return service->fn();
 352}
 353
 354static int upload_pack(void)
 355{
 356        /* Timeout as string */
 357        char timeout_buf[64];
 358
 359        snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 360
 361        /* git-upload-pack only ever reads stuff, so this is safe */
 362        execl_git_cmd("upload-pack", "--strict", timeout_buf, ".", NULL);
 363        return -1;
 364}
 365
 366static int upload_archive(void)
 367{
 368        execl_git_cmd("upload-archive", ".", NULL);
 369        return -1;
 370}
 371
 372static int receive_pack(void)
 373{
 374        execl_git_cmd("receive-pack", ".", NULL);
 375        return -1;
 376}
 377
 378static struct daemon_service daemon_service[] = {
 379        { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 380        { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 381        { "receive-pack", "receivepack", receive_pack, 0, 1 },
 382};
 383
 384static void enable_service(const char *name, int ena)
 385{
 386        int i;
 387        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 388                if (!strcmp(daemon_service[i].name, name)) {
 389                        daemon_service[i].enabled = ena;
 390                        return;
 391                }
 392        }
 393        die("No such service %s", name);
 394}
 395
 396static void make_service_overridable(const char *name, int ena)
 397{
 398        int i;
 399        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 400                if (!strcmp(daemon_service[i].name, name)) {
 401                        daemon_service[i].overridable = ena;
 402                        return;
 403                }
 404        }
 405        die("No such service %s", name);
 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        char *hp;
 417
 418        while (extra_args < end && *extra_args) {
 419                saw_extended_args = 1;
 420                if (strncasecmp("host=", extra_args, 5) == 0) {
 421                        val = extra_args + 5;
 422                        vallen = strlen(val) + 1;
 423                        if (*val) {
 424                                /* Split <host>:<port> at colon. */
 425                                char *host = val;
 426                                char *port = strrchr(host, ':');
 427                                if (port) {
 428                                        *port = 0;
 429                                        port++;
 430                                        free(tcp_port);
 431                                        tcp_port = xstrdup(port);
 432                                }
 433                                free(hostname);
 434                                hostname = xstrdup(host);
 435                        }
 436
 437                        /* On to the next one */
 438                        extra_args = val + vallen;
 439                }
 440        }
 441
 442        /*
 443         * Replace literal host with lowercase-ized hostname.
 444         */
 445        hp = hostname;
 446        if (!hp)
 447                return;
 448        for ( ; *hp; hp++)
 449                *hp = tolower(*hp);
 450
 451        /*
 452         * Locate canonical hostname and its IP address.
 453         */
 454#ifndef NO_IPV6
 455        {
 456                struct addrinfo hints;
 457                struct addrinfo *ai, *ai0;
 458                int gai;
 459                static char addrbuf[HOST_NAME_MAX + 1];
 460
 461                memset(&hints, 0, sizeof(hints));
 462                hints.ai_flags = AI_CANONNAME;
 463
 464                gai = getaddrinfo(hostname, 0, &hints, &ai0);
 465                if (!gai) {
 466                        for (ai = ai0; ai; ai = ai->ai_next) {
 467                                struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 468
 469                                inet_ntop(AF_INET, &sin_addr->sin_addr,
 470                                          addrbuf, sizeof(addrbuf));
 471                                free(canon_hostname);
 472                                canon_hostname = xstrdup(ai->ai_canonname);
 473                                free(ip_address);
 474                                ip_address = xstrdup(addrbuf);
 475                                break;
 476                        }
 477                        freeaddrinfo(ai0);
 478                }
 479        }
 480#else
 481        {
 482                struct hostent *hent;
 483                struct sockaddr_in sa;
 484                char **ap;
 485                static char addrbuf[HOST_NAME_MAX + 1];
 486
 487                hent = gethostbyname(hostname);
 488
 489                ap = hent->h_addr_list;
 490                memset(&sa, 0, sizeof sa);
 491                sa.sin_family = hent->h_addrtype;
 492                sa.sin_port = htons(0);
 493                memcpy(&sa.sin_addr, *ap, hent->h_length);
 494
 495                inet_ntop(hent->h_addrtype, &sa.sin_addr,
 496                          addrbuf, sizeof(addrbuf));
 497
 498                free(canon_hostname);
 499                canon_hostname = xstrdup(hent->h_name);
 500                free(ip_address);
 501                ip_address = xstrdup(addrbuf);
 502        }
 503#endif
 504}
 505
 506
 507static int execute(struct sockaddr *addr)
 508{
 509        static char line[1000];
 510        int pktlen, len, i;
 511
 512        if (addr) {
 513                char addrbuf[256] = "";
 514                int port = -1;
 515
 516                if (addr->sa_family == AF_INET) {
 517                        struct sockaddr_in *sin_addr = (void *) addr;
 518                        inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
 519                        port = ntohs(sin_addr->sin_port);
 520#ifndef NO_IPV6
 521                } else if (addr && addr->sa_family == AF_INET6) {
 522                        struct sockaddr_in6 *sin6_addr = (void *) addr;
 523
 524                        char *buf = addrbuf;
 525                        *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 526                        inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
 527                        strcat(buf, "]");
 528
 529                        port = ntohs(sin6_addr->sin6_port);
 530#endif
 531                }
 532                loginfo("Connection from %s:%d", addrbuf, port);
 533                setenv("REMOTE_ADDR", addrbuf, 1);
 534        }
 535        else {
 536                unsetenv("REMOTE_ADDR");
 537        }
 538
 539        alarm(init_timeout ? init_timeout : timeout);
 540        pktlen = packet_read_line(0, line, sizeof(line));
 541        alarm(0);
 542
 543        len = strlen(line);
 544        if (pktlen != len)
 545                loginfo("Extended attributes (%d bytes) exist <%.*s>",
 546                        (int) pktlen - len,
 547                        (int) pktlen - len, line + len + 1);
 548        if (len && line[len-1] == '\n') {
 549                line[--len] = 0;
 550                pktlen--;
 551        }
 552
 553        free(hostname);
 554        free(canon_hostname);
 555        free(ip_address);
 556        free(tcp_port);
 557        hostname = canon_hostname = ip_address = tcp_port = NULL;
 558
 559        if (len != pktlen)
 560                parse_extra_args(line + len + 1, pktlen - len - 1);
 561
 562        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 563                struct daemon_service *s = &(daemon_service[i]);
 564                int namelen = strlen(s->name);
 565                if (!prefixcmp(line, "git-") &&
 566                    !strncmp(s->name, line + 4, namelen) &&
 567                    line[namelen + 4] == ' ') {
 568                        /*
 569                         * Note: The directory here is probably context sensitive,
 570                         * and might depend on the actual service being performed.
 571                         */
 572                        return run_service(line + namelen + 5, s);
 573                }
 574        }
 575
 576        logerror("Protocol error: '%s'", line);
 577        return -1;
 578}
 579
 580static int max_connections = 32;
 581
 582static unsigned int live_children;
 583
 584static struct child {
 585        struct child *next;
 586        pid_t pid;
 587        struct sockaddr_storage address;
 588} *firstborn;
 589
 590static void add_child(pid_t pid, struct sockaddr *addr, int addrlen)
 591{
 592        struct child *newborn, **cradle;
 593
 594        /*
 595         * This must be xcalloc() -- we'll compare the whole sockaddr_storage
 596         * but individual address may be shorter.
 597         */
 598        newborn = xcalloc(1, sizeof(*newborn));
 599        live_children++;
 600        newborn->pid = pid;
 601        memcpy(&newborn->address, addr, addrlen);
 602        for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 603                if (!memcmp(&(*cradle)->address, &newborn->address,
 604                            sizeof(newborn->address)))
 605                        break;
 606        newborn->next = *cradle;
 607        *cradle = newborn;
 608}
 609
 610static void remove_child(pid_t pid)
 611{
 612        struct child **cradle, *blanket;
 613
 614        for (cradle = &firstborn; (blanket = *cradle); cradle = &blanket->next)
 615                if (blanket->pid == pid) {
 616                        *cradle = blanket->next;
 617                        live_children--;
 618                        free(blanket);
 619                        break;
 620                }
 621}
 622
 623/*
 624 * This gets called if the number of connections grows
 625 * past "max_connections".
 626 *
 627 * We kill the newest connection from a duplicate IP.
 628 */
 629static void kill_some_child(void)
 630{
 631        const struct child *blanket, *next;
 632
 633        if (!(blanket = firstborn))
 634                return;
 635
 636        for (; (next = blanket->next); blanket = next)
 637                if (!memcmp(&blanket->address, &next->address,
 638                            sizeof(next->address))) {
 639                        kill(blanket->pid, SIGTERM);
 640                        break;
 641                }
 642}
 643
 644static void check_dead_children(void)
 645{
 646        int status;
 647        pid_t pid;
 648
 649        while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
 650                const char *dead = "";
 651                remove_child(pid);
 652                if (!WIFEXITED(status) || (WEXITSTATUS(status) > 0))
 653                        dead = " (with error)";
 654                loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 655        }
 656}
 657
 658static void handle(int incoming, struct sockaddr *addr, int addrlen)
 659{
 660        pid_t pid;
 661
 662        if (max_connections && live_children >= max_connections) {
 663                kill_some_child();
 664                sleep(1);  /* give it some time to die */
 665                check_dead_children();
 666                if (live_children >= max_connections) {
 667                        close(incoming);
 668                        logerror("Too many children, dropping connection");
 669                        return;
 670                }
 671        }
 672
 673        if ((pid = fork())) {
 674                close(incoming);
 675                if (pid < 0) {
 676                        logerror("Couldn't fork %s", strerror(errno));
 677                        return;
 678                }
 679
 680                add_child(pid, addr, addrlen);
 681                return;
 682        }
 683
 684        dup2(incoming, 0);
 685        dup2(incoming, 1);
 686        close(incoming);
 687
 688        exit(execute(addr));
 689}
 690
 691static void child_handler(int signo)
 692{
 693        /*
 694         * Otherwise empty handler because systemcalls will get interrupted
 695         * upon signal receipt
 696         * SysV needs the handler to be rearmed
 697         */
 698        signal(SIGCHLD, child_handler);
 699}
 700
 701static int set_reuse_addr(int sockfd)
 702{
 703        int on = 1;
 704
 705        if (!reuseaddr)
 706                return 0;
 707        return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 708                          &on, sizeof(on));
 709}
 710
 711#ifndef NO_IPV6
 712
 713static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 714{
 715        int socknum = 0, *socklist = NULL;
 716        int maxfd = -1;
 717        char pbuf[NI_MAXSERV];
 718        struct addrinfo hints, *ai0, *ai;
 719        int gai;
 720        long flags;
 721
 722        sprintf(pbuf, "%d", listen_port);
 723        memset(&hints, 0, sizeof(hints));
 724        hints.ai_family = AF_UNSPEC;
 725        hints.ai_socktype = SOCK_STREAM;
 726        hints.ai_protocol = IPPROTO_TCP;
 727        hints.ai_flags = AI_PASSIVE;
 728
 729        gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 730        if (gai)
 731                die("getaddrinfo() failed: %s\n", gai_strerror(gai));
 732
 733        for (ai = ai0; ai; ai = ai->ai_next) {
 734                int sockfd;
 735
 736                sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 737                if (sockfd < 0)
 738                        continue;
 739                if (sockfd >= FD_SETSIZE) {
 740                        logerror("Socket descriptor too large");
 741                        close(sockfd);
 742                        continue;
 743                }
 744
 745#ifdef IPV6_V6ONLY
 746                if (ai->ai_family == AF_INET6) {
 747                        int on = 1;
 748                        setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 749                                   &on, sizeof(on));
 750                        /* Note: error is not fatal */
 751                }
 752#endif
 753
 754                if (set_reuse_addr(sockfd)) {
 755                        close(sockfd);
 756                        continue;
 757                }
 758
 759                if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 760                        close(sockfd);
 761                        continue;       /* not fatal */
 762                }
 763                if (listen(sockfd, 5) < 0) {
 764                        close(sockfd);
 765                        continue;       /* not fatal */
 766                }
 767
 768                flags = fcntl(sockfd, F_GETFD, 0);
 769                if (flags >= 0)
 770                        fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 771
 772                socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
 773                socklist[socknum++] = sockfd;
 774
 775                if (maxfd < sockfd)
 776                        maxfd = sockfd;
 777        }
 778
 779        freeaddrinfo(ai0);
 780
 781        *socklist_p = socklist;
 782        return socknum;
 783}
 784
 785#else /* NO_IPV6 */
 786
 787static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 788{
 789        struct sockaddr_in sin;
 790        int sockfd;
 791        long flags;
 792
 793        memset(&sin, 0, sizeof sin);
 794        sin.sin_family = AF_INET;
 795        sin.sin_port = htons(listen_port);
 796
 797        if (listen_addr) {
 798                /* Well, host better be an IP address here. */
 799                if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 800                        return 0;
 801        } else {
 802                sin.sin_addr.s_addr = htonl(INADDR_ANY);
 803        }
 804
 805        sockfd = socket(AF_INET, SOCK_STREAM, 0);
 806        if (sockfd < 0)
 807                return 0;
 808
 809        if (set_reuse_addr(sockfd)) {
 810                close(sockfd);
 811                return 0;
 812        }
 813
 814        if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 815                close(sockfd);
 816                return 0;
 817        }
 818
 819        if (listen(sockfd, 5) < 0) {
 820                close(sockfd);
 821                return 0;
 822        }
 823
 824        flags = fcntl(sockfd, F_GETFD, 0);
 825        if (flags >= 0)
 826                fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 827
 828        *socklist_p = xmalloc(sizeof(int));
 829        **socklist_p = sockfd;
 830        return 1;
 831}
 832
 833#endif
 834
 835static int service_loop(int socknum, int *socklist)
 836{
 837        struct pollfd *pfd;
 838        int i;
 839
 840        pfd = xcalloc(socknum, sizeof(struct pollfd));
 841
 842        for (i = 0; i < socknum; i++) {
 843                pfd[i].fd = socklist[i];
 844                pfd[i].events = POLLIN;
 845        }
 846
 847        signal(SIGCHLD, child_handler);
 848
 849        for (;;) {
 850                int i;
 851
 852                check_dead_children();
 853
 854                if (poll(pfd, socknum, -1) < 0) {
 855                        if (errno != EINTR) {
 856                                logerror("Poll failed, resuming: %s",
 857                                      strerror(errno));
 858                                sleep(1);
 859                        }
 860                        continue;
 861                }
 862
 863                for (i = 0; i < socknum; i++) {
 864                        if (pfd[i].revents & POLLIN) {
 865                                struct sockaddr_storage ss;
 866                                unsigned int sslen = sizeof(ss);
 867                                int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
 868                                if (incoming < 0) {
 869                                        switch (errno) {
 870                                        case EAGAIN:
 871                                        case EINTR:
 872                                        case ECONNABORTED:
 873                                                continue;
 874                                        default:
 875                                                die("accept returned %s", strerror(errno));
 876                                        }
 877                                }
 878                                handle(incoming, (struct sockaddr *)&ss, sslen);
 879                        }
 880                }
 881        }
 882}
 883
 884/* if any standard file descriptor is missing open it to /dev/null */
 885static void sanitize_stdfds(void)
 886{
 887        int fd = open("/dev/null", O_RDWR, 0);
 888        while (fd != -1 && fd < 2)
 889                fd = dup(fd);
 890        if (fd == -1)
 891                die("open /dev/null or dup failed: %s", strerror(errno));
 892        if (fd > 2)
 893                close(fd);
 894}
 895
 896static void daemonize(void)
 897{
 898        switch (fork()) {
 899                case 0:
 900                        break;
 901                case -1:
 902                        die("fork failed: %s", strerror(errno));
 903                default:
 904                        exit(0);
 905        }
 906        if (setsid() == -1)
 907                die("setsid failed: %s", strerror(errno));
 908        close(0);
 909        close(1);
 910        close(2);
 911        sanitize_stdfds();
 912}
 913
 914static void store_pid(const char *path)
 915{
 916        FILE *f = fopen(path, "w");
 917        if (!f)
 918                die("cannot open pid file %s: %s", path, strerror(errno));
 919        if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
 920                die("failed to write pid file %s: %s", path, strerror(errno));
 921}
 922
 923static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
 924{
 925        int socknum, *socklist;
 926
 927        socknum = socksetup(listen_addr, listen_port, &socklist);
 928        if (socknum == 0)
 929                die("unable to allocate any listen sockets on host %s port %u",
 930                    listen_addr, listen_port);
 931
 932        if (pass && gid &&
 933            (initgroups(pass->pw_name, gid) || setgid (gid) ||
 934             setuid(pass->pw_uid)))
 935                die("cannot drop privileges");
 936
 937        return service_loop(socknum, socklist);
 938}
 939
 940int main(int argc, char **argv)
 941{
 942        int listen_port = 0;
 943        char *listen_addr = NULL;
 944        int inetd_mode = 0;
 945        const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
 946        int detach = 0;
 947        struct passwd *pass = NULL;
 948        struct group *group;
 949        gid_t gid = 0;
 950        int i;
 951
 952        for (i = 1; i < argc; i++) {
 953                char *arg = argv[i];
 954
 955                if (!prefixcmp(arg, "--listen=")) {
 956                    char *p = arg + 9;
 957                    char *ph = listen_addr = xmalloc(strlen(arg + 9) + 1);
 958                    while (*p)
 959                        *ph++ = tolower(*p++);
 960                    *ph = 0;
 961                    continue;
 962                }
 963                if (!prefixcmp(arg, "--port=")) {
 964                        char *end;
 965                        unsigned long n;
 966                        n = strtoul(arg+7, &end, 0);
 967                        if (arg[7] && !*end) {
 968                                listen_port = n;
 969                                continue;
 970                        }
 971                }
 972                if (!strcmp(arg, "--inetd")) {
 973                        inetd_mode = 1;
 974                        log_syslog = 1;
 975                        continue;
 976                }
 977                if (!strcmp(arg, "--verbose")) {
 978                        verbose = 1;
 979                        continue;
 980                }
 981                if (!strcmp(arg, "--syslog")) {
 982                        log_syslog = 1;
 983                        continue;
 984                }
 985                if (!strcmp(arg, "--export-all")) {
 986                        export_all_trees = 1;
 987                        continue;
 988                }
 989                if (!prefixcmp(arg, "--timeout=")) {
 990                        timeout = atoi(arg+10);
 991                        continue;
 992                }
 993                if (!prefixcmp(arg, "--init-timeout=")) {
 994                        init_timeout = atoi(arg+15);
 995                        continue;
 996                }
 997                if (!prefixcmp(arg, "--max-connections=")) {
 998                        max_connections = atoi(arg+18);
 999                        if (max_connections < 0)
1000                                max_connections = 0;            /* unlimited */
1001                        continue;
1002                }
1003                if (!strcmp(arg, "--strict-paths")) {
1004                        strict_paths = 1;
1005                        continue;
1006                }
1007                if (!prefixcmp(arg, "--base-path=")) {
1008                        base_path = arg+12;
1009                        continue;
1010                }
1011                if (!strcmp(arg, "--base-path-relaxed")) {
1012                        base_path_relaxed = 1;
1013                        continue;
1014                }
1015                if (!prefixcmp(arg, "--interpolated-path=")) {
1016                        interpolated_path = arg+20;
1017                        continue;
1018                }
1019                if (!strcmp(arg, "--reuseaddr")) {
1020                        reuseaddr = 1;
1021                        continue;
1022                }
1023                if (!strcmp(arg, "--user-path")) {
1024                        user_path = "";
1025                        continue;
1026                }
1027                if (!prefixcmp(arg, "--user-path=")) {
1028                        user_path = arg + 12;
1029                        continue;
1030                }
1031                if (!prefixcmp(arg, "--pid-file=")) {
1032                        pid_file = arg + 11;
1033                        continue;
1034                }
1035                if (!strcmp(arg, "--detach")) {
1036                        detach = 1;
1037                        log_syslog = 1;
1038                        continue;
1039                }
1040                if (!prefixcmp(arg, "--user=")) {
1041                        user_name = arg + 7;
1042                        continue;
1043                }
1044                if (!prefixcmp(arg, "--group=")) {
1045                        group_name = arg + 8;
1046                        continue;
1047                }
1048                if (!prefixcmp(arg, "--enable=")) {
1049                        enable_service(arg + 9, 1);
1050                        continue;
1051                }
1052                if (!prefixcmp(arg, "--disable=")) {
1053                        enable_service(arg + 10, 0);
1054                        continue;
1055                }
1056                if (!prefixcmp(arg, "--allow-override=")) {
1057                        make_service_overridable(arg + 17, 1);
1058                        continue;
1059                }
1060                if (!prefixcmp(arg, "--forbid-override=")) {
1061                        make_service_overridable(arg + 18, 0);
1062                        continue;
1063                }
1064                if (!strcmp(arg, "--")) {
1065                        ok_paths = &argv[i+1];
1066                        break;
1067                } else if (arg[0] != '-') {
1068                        ok_paths = &argv[i];
1069                        break;
1070                }
1071
1072                usage(daemon_usage);
1073        }
1074
1075        if (log_syslog) {
1076                openlog("git-daemon", LOG_PID, LOG_DAEMON);
1077                set_die_routine(daemon_die);
1078        } else
1079                /* avoid splitting a message in the middle */
1080                setvbuf(stderr, NULL, _IOLBF, 0);
1081
1082        if (inetd_mode && (group_name || user_name))
1083                die("--user and --group are incompatible with --inetd");
1084
1085        if (inetd_mode && (listen_port || listen_addr))
1086                die("--listen= and --port= are incompatible with --inetd");
1087        else if (listen_port == 0)
1088                listen_port = DEFAULT_GIT_PORT;
1089
1090        if (group_name && !user_name)
1091                die("--group supplied without --user");
1092
1093        if (user_name) {
1094                pass = getpwnam(user_name);
1095                if (!pass)
1096                        die("user not found - %s", user_name);
1097
1098                if (!group_name)
1099                        gid = pass->pw_gid;
1100                else {
1101                        group = getgrnam(group_name);
1102                        if (!group)
1103                                die("group not found - %s", group_name);
1104
1105                        gid = group->gr_gid;
1106                }
1107        }
1108
1109        if (strict_paths && (!ok_paths || !*ok_paths))
1110                die("option --strict-paths requires a whitelist");
1111
1112        if (base_path && !is_directory(base_path))
1113                die("base-path '%s' does not exist or is not a directory",
1114                    base_path);
1115
1116        if (inetd_mode) {
1117                struct sockaddr_storage ss;
1118                struct sockaddr *peer = (struct sockaddr *)&ss;
1119                socklen_t slen = sizeof(ss);
1120
1121                freopen("/dev/null", "w", stderr);
1122
1123                if (getpeername(0, peer, &slen))
1124                        peer = NULL;
1125
1126                return execute(peer);
1127        }
1128
1129        if (detach) {
1130                daemonize();
1131                loginfo("Ready to rumble");
1132        }
1133        else
1134                sanitize_stdfds();
1135
1136        if (pid_file)
1137                store_pid(pid_file);
1138
1139        return serve(listen_addr, listen_port, pass, gid);
1140}