Andrew's git / gitweb.git / daemon.c
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daemon.con commit builtin-notes: Add "append" subcommand for appending to note objects (2347fae)
   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
  80__attribute__((format (printf, 1, 2)))
  81static void logerror(const char *err, ...)
  82{
  83        va_list params;
  84        va_start(params, err);
  85        logreport(LOG_ERR, err, params);
  86        va_end(params);
  87}
  88
  89__attribute__((format (printf, 1, 2)))
  90static void loginfo(const char *err, ...)
  91{
  92        va_list params;
  93        if (!verbose)
  94                return;
  95        va_start(params, err);
  96        logreport(LOG_INFO, err, params);
  97        va_end(params);
  98}
  99
 100static void NORETURN daemon_die(const char *err, va_list params)
 101{
 102        logreport(LOG_ERR, err, params);
 103        exit(1);
 104}
 105
 106static char *path_ok(char *directory)
 107{
 108        static char rpath[PATH_MAX];
 109        static char interp_path[PATH_MAX];
 110        char *path;
 111        char *dir;
 112
 113        dir = directory;
 114
 115        if (daemon_avoid_alias(dir)) {
 116                logerror("'%s': aliased", dir);
 117                return NULL;
 118        }
 119
 120        if (*dir == '~') {
 121                if (!user_path) {
 122                        logerror("'%s': User-path not allowed", dir);
 123                        return NULL;
 124                }
 125                if (*user_path) {
 126                        /* Got either "~alice" or "~alice/foo";
 127                         * rewrite them to "~alice/%s" or
 128                         * "~alice/%s/foo".
 129                         */
 130                        int namlen, restlen = strlen(dir);
 131                        char *slash = strchr(dir, '/');
 132                        if (!slash)
 133                                slash = dir + restlen;
 134                        namlen = slash - dir;
 135                        restlen -= namlen;
 136                        loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
 137                        snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
 138                                 namlen, dir, user_path, restlen, slash);
 139                        dir = rpath;
 140                }
 141        }
 142        else if (interpolated_path && saw_extended_args) {
 143                struct strbuf expanded_path = STRBUF_INIT;
 144                struct strbuf_expand_dict_entry dict[] = {
 145                        { "H", hostname },
 146                        { "CH", canon_hostname },
 147                        { "IP", ip_address },
 148                        { "P", tcp_port },
 149                        { "D", directory },
 150                        { NULL }
 151                };
 152
 153                if (*dir != '/') {
 154                        /* Allow only absolute */
 155                        logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 156                        return NULL;
 157                }
 158
 159                strbuf_expand(&expanded_path, interpolated_path,
 160                                strbuf_expand_dict_cb, &dict);
 161                strlcpy(interp_path, expanded_path.buf, PATH_MAX);
 162                strbuf_release(&expanded_path);
 163                loginfo("Interpolated dir '%s'", interp_path);
 164
 165                dir = interp_path;
 166        }
 167        else if (base_path) {
 168                if (*dir != '/') {
 169                        /* Allow only absolute */
 170                        logerror("'%s': Non-absolute path denied (base-path active)", dir);
 171                        return NULL;
 172                }
 173                snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
 174                dir = rpath;
 175        }
 176
 177        path = enter_repo(dir, strict_paths);
 178        if (!path && base_path && base_path_relaxed) {
 179                /*
 180                 * if we fail and base_path_relaxed is enabled, try without
 181                 * prefixing the base path
 182                 */
 183                dir = directory;
 184                path = enter_repo(dir, strict_paths);
 185        }
 186
 187        if (!path) {
 188                logerror("'%s' does not appear to be a git repository", dir);
 189                return NULL;
 190        }
 191
 192        if ( ok_paths && *ok_paths ) {
 193                char **pp;
 194                int pathlen = strlen(path);
 195
 196                /* The validation is done on the paths after enter_repo
 197                 * appends optional {.git,.git/.git} and friends, but
 198                 * it does not use getcwd().  So if your /pub is
 199                 * a symlink to /mnt/pub, you can whitelist /pub and
 200                 * do not have to say /mnt/pub.
 201                 * Do not say /pub/.
 202                 */
 203                for ( pp = ok_paths ; *pp ; pp++ ) {
 204                        int len = strlen(*pp);
 205                        if (len <= pathlen &&
 206                            !memcmp(*pp, path, len) &&
 207                            (path[len] == '\0' ||
 208                             (!strict_paths && path[len] == '/')))
 209                                return path;
 210                }
 211        }
 212        else {
 213                /* be backwards compatible */
 214                if (!strict_paths)
 215                        return path;
 216        }
 217
 218        logerror("'%s': not in whitelist", path);
 219        return NULL;            /* Fallthrough. Deny by default */
 220}
 221
 222typedef int (*daemon_service_fn)(void);
 223struct daemon_service {
 224        const char *name;
 225        const char *config_name;
 226        daemon_service_fn fn;
 227        int enabled;
 228        int overridable;
 229};
 230
 231static struct daemon_service *service_looking_at;
 232static int service_enabled;
 233
 234static int git_daemon_config(const char *var, const char *value, void *cb)
 235{
 236        if (!prefixcmp(var, "daemon.") &&
 237            !strcmp(var + 7, service_looking_at->config_name)) {
 238                service_enabled = git_config_bool(var, value);
 239                return 0;
 240        }
 241
 242        /* we are not interested in parsing any other configuration here */
 243        return 0;
 244}
 245
 246static int run_service(char *dir, struct daemon_service *service)
 247{
 248        const char *path;
 249        int enabled = service->enabled;
 250
 251        loginfo("Request %s for '%s'", service->name, dir);
 252
 253        if (!enabled && !service->overridable) {
 254                logerror("'%s': service not enabled.", service->name);
 255                errno = EACCES;
 256                return -1;
 257        }
 258
 259        if (!(path = path_ok(dir)))
 260                return -1;
 261
 262        /*
 263         * Security on the cheap.
 264         *
 265         * We want a readable HEAD, usable "objects" directory, and
 266         * a "git-daemon-export-ok" flag that says that the other side
 267         * is ok with us doing this.
 268         *
 269         * path_ok() uses enter_repo() and does whitelist checking.
 270         * We only need to make sure the repository is exported.
 271         */
 272
 273        if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 274                logerror("'%s': repository not exported.", path);
 275                errno = EACCES;
 276                return -1;
 277        }
 278
 279        if (service->overridable) {
 280                service_looking_at = service;
 281                service_enabled = -1;
 282                git_config(git_daemon_config, NULL);
 283                if (0 <= service_enabled)
 284                        enabled = service_enabled;
 285        }
 286        if (!enabled) {
 287                logerror("'%s': service not enabled for '%s'",
 288                         service->name, path);
 289                errno = EACCES;
 290                return -1;
 291        }
 292
 293        /*
 294         * We'll ignore SIGTERM from now on, we have a
 295         * good client.
 296         */
 297        signal(SIGTERM, SIG_IGN);
 298
 299        return service->fn();
 300}
 301
 302static void copy_to_log(int fd)
 303{
 304        struct strbuf line = STRBUF_INIT;
 305        FILE *fp;
 306
 307        fp = fdopen(fd, "r");
 308        if (fp == NULL) {
 309                logerror("fdopen of error channel failed");
 310                close(fd);
 311                return;
 312        }
 313
 314        while (strbuf_getline(&line, fp, '\n') != EOF) {
 315                logerror("%s", line.buf);
 316                strbuf_setlen(&line, 0);
 317        }
 318
 319        strbuf_release(&line);
 320        fclose(fp);
 321}
 322
 323static int run_service_command(const char **argv)
 324{
 325        struct child_process cld;
 326
 327        memset(&cld, 0, sizeof(cld));
 328        cld.argv = argv;
 329        cld.git_cmd = 1;
 330        cld.err = -1;
 331        if (start_command(&cld))
 332                return -1;
 333
 334        close(0);
 335        close(1);
 336
 337        copy_to_log(cld.err);
 338
 339        return finish_command(&cld);
 340}
 341
 342static int upload_pack(void)
 343{
 344        /* Timeout as string */
 345        char timeout_buf[64];
 346        const char *argv[] = { "upload-pack", "--strict", timeout_buf, ".", NULL };
 347
 348        snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 349        return run_service_command(argv);
 350}
 351
 352static int upload_archive(void)
 353{
 354        static const char *argv[] = { "upload-archive", ".", NULL };
 355        return run_service_command(argv);
 356}
 357
 358static int receive_pack(void)
 359{
 360        static const char *argv[] = { "receive-pack", ".", NULL };
 361        return run_service_command(argv);
 362}
 363
 364static struct daemon_service daemon_service[] = {
 365        { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 366        { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 367        { "receive-pack", "receivepack", receive_pack, 0, 1 },
 368};
 369
 370static void enable_service(const char *name, int ena)
 371{
 372        int i;
 373        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 374                if (!strcmp(daemon_service[i].name, name)) {
 375                        daemon_service[i].enabled = ena;
 376                        return;
 377                }
 378        }
 379        die("No such service %s", name);
 380}
 381
 382static void make_service_overridable(const char *name, int ena)
 383{
 384        int i;
 385        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 386                if (!strcmp(daemon_service[i].name, name)) {
 387                        daemon_service[i].overridable = ena;
 388                        return;
 389                }
 390        }
 391        die("No such service %s", name);
 392}
 393
 394static char *xstrdup_tolower(const char *str)
 395{
 396        char *p, *dup = xstrdup(str);
 397        for (p = dup; *p; p++)
 398                *p = tolower(*p);
 399        return dup;
 400}
 401
 402/*
 403 * Read the host as supplied by the client connection.
 404 */
 405static void parse_host_arg(char *extra_args, int buflen)
 406{
 407        char *val;
 408        int vallen;
 409        char *end = extra_args + buflen;
 410
 411        if (extra_args < end && *extra_args) {
 412                saw_extended_args = 1;
 413                if (strncasecmp("host=", extra_args, 5) == 0) {
 414                        val = extra_args + 5;
 415                        vallen = strlen(val) + 1;
 416                        if (*val) {
 417                                /* Split <host>:<port> at colon. */
 418                                char *host = val;
 419                                char *port = strrchr(host, ':');
 420                                if (port) {
 421                                        *port = 0;
 422                                        port++;
 423                                        free(tcp_port);
 424                                        tcp_port = xstrdup(port);
 425                                }
 426                                free(hostname);
 427                                hostname = xstrdup_tolower(host);
 428                        }
 429
 430                        /* On to the next one */
 431                        extra_args = val + vallen;
 432                }
 433                if (extra_args < end && *extra_args)
 434                        die("Invalid request");
 435        }
 436
 437        /*
 438         * Locate canonical hostname and its IP address.
 439         */
 440        if (hostname) {
 441#ifndef NO_IPV6
 442                struct addrinfo hints;
 443                struct addrinfo *ai;
 444                int gai;
 445                static char addrbuf[HOST_NAME_MAX + 1];
 446
 447                memset(&hints, 0, sizeof(hints));
 448                hints.ai_flags = AI_CANONNAME;
 449
 450                gai = getaddrinfo(hostname, NULL, &hints, &ai);
 451                if (!gai) {
 452                        struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 453
 454                        inet_ntop(AF_INET, &sin_addr->sin_addr,
 455                                  addrbuf, sizeof(addrbuf));
 456                        free(ip_address);
 457                        ip_address = xstrdup(addrbuf);
 458
 459                        free(canon_hostname);
 460                        canon_hostname = xstrdup(ai->ai_canonname ?
 461                                                 ai->ai_canonname : ip_address);
 462
 463                        freeaddrinfo(ai);
 464                }
 465#else
 466                struct hostent *hent;
 467                struct sockaddr_in sa;
 468                char **ap;
 469                static char addrbuf[HOST_NAME_MAX + 1];
 470
 471                hent = gethostbyname(hostname);
 472
 473                ap = hent->h_addr_list;
 474                memset(&sa, 0, sizeof sa);
 475                sa.sin_family = hent->h_addrtype;
 476                sa.sin_port = htons(0);
 477                memcpy(&sa.sin_addr, *ap, hent->h_length);
 478
 479                inet_ntop(hent->h_addrtype, &sa.sin_addr,
 480                          addrbuf, sizeof(addrbuf));
 481
 482                free(canon_hostname);
 483                canon_hostname = xstrdup(hent->h_name);
 484                free(ip_address);
 485                ip_address = xstrdup(addrbuf);
 486#endif
 487        }
 488}
 489
 490
 491static int execute(struct sockaddr *addr)
 492{
 493        static char line[1000];
 494        int pktlen, len, i;
 495
 496        if (addr) {
 497                char addrbuf[256] = "";
 498                int port = -1;
 499
 500                if (addr->sa_family == AF_INET) {
 501                        struct sockaddr_in *sin_addr = (void *) addr;
 502                        inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
 503                        port = ntohs(sin_addr->sin_port);
 504#ifndef NO_IPV6
 505                } else if (addr && addr->sa_family == AF_INET6) {
 506                        struct sockaddr_in6 *sin6_addr = (void *) addr;
 507
 508                        char *buf = addrbuf;
 509                        *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 510                        inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
 511                        strcat(buf, "]");
 512
 513                        port = ntohs(sin6_addr->sin6_port);
 514#endif
 515                }
 516                loginfo("Connection from %s:%d", addrbuf, port);
 517                setenv("REMOTE_ADDR", addrbuf, 1);
 518        }
 519        else {
 520                unsetenv("REMOTE_ADDR");
 521        }
 522
 523        alarm(init_timeout ? init_timeout : timeout);
 524        pktlen = packet_read_line(0, line, sizeof(line));
 525        alarm(0);
 526
 527        len = strlen(line);
 528        if (pktlen != len)
 529                loginfo("Extended attributes (%d bytes) exist <%.*s>",
 530                        (int) pktlen - len,
 531                        (int) pktlen - len, line + len + 1);
 532        if (len && line[len-1] == '\n') {
 533                line[--len] = 0;
 534                pktlen--;
 535        }
 536
 537        free(hostname);
 538        free(canon_hostname);
 539        free(ip_address);
 540        free(tcp_port);
 541        hostname = canon_hostname = ip_address = tcp_port = NULL;
 542
 543        if (len != pktlen)
 544                parse_host_arg(line + len + 1, pktlen - len - 1);
 545
 546        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 547                struct daemon_service *s = &(daemon_service[i]);
 548                int namelen = strlen(s->name);
 549                if (!prefixcmp(line, "git-") &&
 550                    !strncmp(s->name, line + 4, namelen) &&
 551                    line[namelen + 4] == ' ') {
 552                        /*
 553                         * Note: The directory here is probably context sensitive,
 554                         * and might depend on the actual service being performed.
 555                         */
 556                        return run_service(line + namelen + 5, s);
 557                }
 558        }
 559
 560        logerror("Protocol error: '%s'", line);
 561        return -1;
 562}
 563
 564static int addrcmp(const struct sockaddr_storage *s1,
 565    const struct sockaddr_storage *s2)
 566{
 567        if (s1->ss_family != s2->ss_family)
 568                return s1->ss_family - s2->ss_family;
 569        if (s1->ss_family == AF_INET)
 570                return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 571                    &((struct sockaddr_in *)s2)->sin_addr,
 572                    sizeof(struct in_addr));
 573#ifndef NO_IPV6
 574        if (s1->ss_family == AF_INET6)
 575                return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 576                    &((struct sockaddr_in6 *)s2)->sin6_addr,
 577                    sizeof(struct in6_addr));
 578#endif
 579        return 0;
 580}
 581
 582static int max_connections = 32;
 583
 584static unsigned int live_children;
 585
 586static struct child {
 587        struct child *next;
 588        pid_t pid;
 589        struct sockaddr_storage address;
 590} *firstborn;
 591
 592static void add_child(pid_t pid, struct sockaddr *addr, int addrlen)
 593{
 594        struct child *newborn, **cradle;
 595
 596        newborn = xcalloc(1, sizeof(*newborn));
 597        live_children++;
 598        newborn->pid = pid;
 599        memcpy(&newborn->address, addr, addrlen);
 600        for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 601                if (!addrcmp(&(*cradle)->address, &newborn->address))
 602                        break;
 603        newborn->next = *cradle;
 604        *cradle = newborn;
 605}
 606
 607static void remove_child(pid_t pid)
 608{
 609        struct child **cradle, *blanket;
 610
 611        for (cradle = &firstborn; (blanket = *cradle); cradle = &blanket->next)
 612                if (blanket->pid == pid) {
 613                        *cradle = blanket->next;
 614                        live_children--;
 615                        free(blanket);
 616                        break;
 617                }
 618}
 619
 620/*
 621 * This gets called if the number of connections grows
 622 * past "max_connections".
 623 *
 624 * We kill the newest connection from a duplicate IP.
 625 */
 626static void kill_some_child(void)
 627{
 628        const struct child *blanket, *next;
 629
 630        if (!(blanket = firstborn))
 631                return;
 632
 633        for (; (next = blanket->next); blanket = next)
 634                if (!addrcmp(&blanket->address, &next->address)) {
 635                        kill(blanket->pid, SIGTERM);
 636                        break;
 637                }
 638}
 639
 640static void check_dead_children(void)
 641{
 642        int status;
 643        pid_t pid;
 644
 645        while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
 646                const char *dead = "";
 647                remove_child(pid);
 648                if (!WIFEXITED(status) || (WEXITSTATUS(status) > 0))
 649                        dead = " (with error)";
 650                loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 651        }
 652}
 653
 654static void handle(int incoming, struct sockaddr *addr, int addrlen)
 655{
 656        pid_t pid;
 657
 658        if (max_connections && live_children >= max_connections) {
 659                kill_some_child();
 660                sleep(1);  /* give it some time to die */
 661                check_dead_children();
 662                if (live_children >= max_connections) {
 663                        close(incoming);
 664                        logerror("Too many children, dropping connection");
 665                        return;
 666                }
 667        }
 668
 669        if ((pid = fork())) {
 670                close(incoming);
 671                if (pid < 0) {
 672                        logerror("Couldn't fork %s", strerror(errno));
 673                        return;
 674                }
 675
 676                add_child(pid, addr, addrlen);
 677                return;
 678        }
 679
 680        dup2(incoming, 0);
 681        dup2(incoming, 1);
 682        close(incoming);
 683
 684        exit(execute(addr));
 685}
 686
 687static void child_handler(int signo)
 688{
 689        /*
 690         * Otherwise empty handler because systemcalls will get interrupted
 691         * upon signal receipt
 692         * SysV needs the handler to be rearmed
 693         */
 694        signal(SIGCHLD, child_handler);
 695}
 696
 697static int set_reuse_addr(int sockfd)
 698{
 699        int on = 1;
 700
 701        if (!reuseaddr)
 702                return 0;
 703        return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 704                          &on, sizeof(on));
 705}
 706
 707#ifndef NO_IPV6
 708
 709static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 710{
 711        int socknum = 0, *socklist = NULL;
 712        int maxfd = -1;
 713        char pbuf[NI_MAXSERV];
 714        struct addrinfo hints, *ai0, *ai;
 715        int gai;
 716        long flags;
 717
 718        sprintf(pbuf, "%d", listen_port);
 719        memset(&hints, 0, sizeof(hints));
 720        hints.ai_family = AF_UNSPEC;
 721        hints.ai_socktype = SOCK_STREAM;
 722        hints.ai_protocol = IPPROTO_TCP;
 723        hints.ai_flags = AI_PASSIVE;
 724
 725        gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 726        if (gai)
 727                die("getaddrinfo() failed: %s", gai_strerror(gai));
 728
 729        for (ai = ai0; ai; ai = ai->ai_next) {
 730                int sockfd;
 731
 732                sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 733                if (sockfd < 0)
 734                        continue;
 735                if (sockfd >= FD_SETSIZE) {
 736                        logerror("Socket descriptor too large");
 737                        close(sockfd);
 738                        continue;
 739                }
 740
 741#ifdef IPV6_V6ONLY
 742                if (ai->ai_family == AF_INET6) {
 743                        int on = 1;
 744                        setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 745                                   &on, sizeof(on));
 746                        /* Note: error is not fatal */
 747                }
 748#endif
 749
 750                if (set_reuse_addr(sockfd)) {
 751                        close(sockfd);
 752                        continue;
 753                }
 754
 755                if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 756                        close(sockfd);
 757                        continue;       /* not fatal */
 758                }
 759                if (listen(sockfd, 5) < 0) {
 760                        close(sockfd);
 761                        continue;       /* not fatal */
 762                }
 763
 764                flags = fcntl(sockfd, F_GETFD, 0);
 765                if (flags >= 0)
 766                        fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 767
 768                socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
 769                socklist[socknum++] = sockfd;
 770
 771                if (maxfd < sockfd)
 772                        maxfd = sockfd;
 773        }
 774
 775        freeaddrinfo(ai0);
 776
 777        *socklist_p = socklist;
 778        return socknum;
 779}
 780
 781#else /* NO_IPV6 */
 782
 783static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 784{
 785        struct sockaddr_in sin;
 786        int sockfd;
 787        long flags;
 788
 789        memset(&sin, 0, sizeof sin);
 790        sin.sin_family = AF_INET;
 791        sin.sin_port = htons(listen_port);
 792
 793        if (listen_addr) {
 794                /* Well, host better be an IP address here. */
 795                if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 796                        return 0;
 797        } else {
 798                sin.sin_addr.s_addr = htonl(INADDR_ANY);
 799        }
 800
 801        sockfd = socket(AF_INET, SOCK_STREAM, 0);
 802        if (sockfd < 0)
 803                return 0;
 804
 805        if (set_reuse_addr(sockfd)) {
 806                close(sockfd);
 807                return 0;
 808        }
 809
 810        if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 811                close(sockfd);
 812                return 0;
 813        }
 814
 815        if (listen(sockfd, 5) < 0) {
 816                close(sockfd);
 817                return 0;
 818        }
 819
 820        flags = fcntl(sockfd, F_GETFD, 0);
 821        if (flags >= 0)
 822                fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 823
 824        *socklist_p = xmalloc(sizeof(int));
 825        **socklist_p = sockfd;
 826        return 1;
 827}
 828
 829#endif
 830
 831static int service_loop(int socknum, int *socklist)
 832{
 833        struct pollfd *pfd;
 834        int i;
 835
 836        pfd = xcalloc(socknum, sizeof(struct pollfd));
 837
 838        for (i = 0; i < socknum; i++) {
 839                pfd[i].fd = socklist[i];
 840                pfd[i].events = POLLIN;
 841        }
 842
 843        signal(SIGCHLD, child_handler);
 844
 845        for (;;) {
 846                int i;
 847
 848                check_dead_children();
 849
 850                if (poll(pfd, socknum, -1) < 0) {
 851                        if (errno != EINTR) {
 852                                logerror("Poll failed, resuming: %s",
 853                                      strerror(errno));
 854                                sleep(1);
 855                        }
 856                        continue;
 857                }
 858
 859                for (i = 0; i < socknum; i++) {
 860                        if (pfd[i].revents & POLLIN) {
 861                                struct sockaddr_storage ss;
 862                                unsigned int sslen = sizeof(ss);
 863                                int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
 864                                if (incoming < 0) {
 865                                        switch (errno) {
 866                                        case EAGAIN:
 867                                        case EINTR:
 868                                        case ECONNABORTED:
 869                                                continue;
 870                                        default:
 871                                                die_errno("accept returned");
 872                                        }
 873                                }
 874                                handle(incoming, (struct sockaddr *)&ss, sslen);
 875                        }
 876                }
 877        }
 878}
 879
 880/* if any standard file descriptor is missing open it to /dev/null */
 881static void sanitize_stdfds(void)
 882{
 883        int fd = open("/dev/null", O_RDWR, 0);
 884        while (fd != -1 && fd < 2)
 885                fd = dup(fd);
 886        if (fd == -1)
 887                die_errno("open /dev/null or dup failed");
 888        if (fd > 2)
 889                close(fd);
 890}
 891
 892static void daemonize(void)
 893{
 894        switch (fork()) {
 895                case 0:
 896                        break;
 897                case -1:
 898                        die_errno("fork failed");
 899                default:
 900                        exit(0);
 901        }
 902        if (setsid() == -1)
 903                die_errno("setsid failed");
 904        close(0);
 905        close(1);
 906        close(2);
 907        sanitize_stdfds();
 908}
 909
 910static void store_pid(const char *path)
 911{
 912        FILE *f = fopen(path, "w");
 913        if (!f)
 914                die_errno("cannot open pid file '%s'", path);
 915        if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
 916                die_errno("failed to write pid file '%s'", path);
 917}
 918
 919static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
 920{
 921        int socknum, *socklist;
 922
 923        socknum = socksetup(listen_addr, listen_port, &socklist);
 924        if (socknum == 0)
 925                die("unable to allocate any listen sockets on host %s port %u",
 926                    listen_addr, listen_port);
 927
 928        if (pass && gid &&
 929            (initgroups(pass->pw_name, gid) || setgid (gid) ||
 930             setuid(pass->pw_uid)))
 931                die("cannot drop privileges");
 932
 933        return service_loop(socknum, socklist);
 934}
 935
 936int main(int argc, char **argv)
 937{
 938        int listen_port = 0;
 939        char *listen_addr = NULL;
 940        int inetd_mode = 0;
 941        const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
 942        int detach = 0;
 943        struct passwd *pass = NULL;
 944        struct group *group;
 945        gid_t gid = 0;
 946        int i;
 947
 948        git_extract_argv0_path(argv[0]);
 949
 950        for (i = 1; i < argc; i++) {
 951                char *arg = argv[i];
 952
 953                if (!prefixcmp(arg, "--listen=")) {
 954                        listen_addr = xstrdup_tolower(arg + 9);
 955                        continue;
 956                }
 957                if (!prefixcmp(arg, "--port=")) {
 958                        char *end;
 959                        unsigned long n;
 960                        n = strtoul(arg+7, &end, 0);
 961                        if (arg[7] && !*end) {
 962                                listen_port = n;
 963                                continue;
 964                        }
 965                }
 966                if (!strcmp(arg, "--inetd")) {
 967                        inetd_mode = 1;
 968                        log_syslog = 1;
 969                        continue;
 970                }
 971                if (!strcmp(arg, "--verbose")) {
 972                        verbose = 1;
 973                        continue;
 974                }
 975                if (!strcmp(arg, "--syslog")) {
 976                        log_syslog = 1;
 977                        continue;
 978                }
 979                if (!strcmp(arg, "--export-all")) {
 980                        export_all_trees = 1;
 981                        continue;
 982                }
 983                if (!prefixcmp(arg, "--timeout=")) {
 984                        timeout = atoi(arg+10);
 985                        continue;
 986                }
 987                if (!prefixcmp(arg, "--init-timeout=")) {
 988                        init_timeout = atoi(arg+15);
 989                        continue;
 990                }
 991                if (!prefixcmp(arg, "--max-connections=")) {
 992                        max_connections = atoi(arg+18);
 993                        if (max_connections < 0)
 994                                max_connections = 0;            /* unlimited */
 995                        continue;
 996                }
 997                if (!strcmp(arg, "--strict-paths")) {
 998                        strict_paths = 1;
 999                        continue;
1000                }
1001                if (!prefixcmp(arg, "--base-path=")) {
1002                        base_path = arg+12;
1003                        continue;
1004                }
1005                if (!strcmp(arg, "--base-path-relaxed")) {
1006                        base_path_relaxed = 1;
1007                        continue;
1008                }
1009                if (!prefixcmp(arg, "--interpolated-path=")) {
1010                        interpolated_path = arg+20;
1011                        continue;
1012                }
1013                if (!strcmp(arg, "--reuseaddr")) {
1014                        reuseaddr = 1;
1015                        continue;
1016                }
1017                if (!strcmp(arg, "--user-path")) {
1018                        user_path = "";
1019                        continue;
1020                }
1021                if (!prefixcmp(arg, "--user-path=")) {
1022                        user_path = arg + 12;
1023                        continue;
1024                }
1025                if (!prefixcmp(arg, "--pid-file=")) {
1026                        pid_file = arg + 11;
1027                        continue;
1028                }
1029                if (!strcmp(arg, "--detach")) {
1030                        detach = 1;
1031                        log_syslog = 1;
1032                        continue;
1033                }
1034                if (!prefixcmp(arg, "--user=")) {
1035                        user_name = arg + 7;
1036                        continue;
1037                }
1038                if (!prefixcmp(arg, "--group=")) {
1039                        group_name = arg + 8;
1040                        continue;
1041                }
1042                if (!prefixcmp(arg, "--enable=")) {
1043                        enable_service(arg + 9, 1);
1044                        continue;
1045                }
1046                if (!prefixcmp(arg, "--disable=")) {
1047                        enable_service(arg + 10, 0);
1048                        continue;
1049                }
1050                if (!prefixcmp(arg, "--allow-override=")) {
1051                        make_service_overridable(arg + 17, 1);
1052                        continue;
1053                }
1054                if (!prefixcmp(arg, "--forbid-override=")) {
1055                        make_service_overridable(arg + 18, 0);
1056                        continue;
1057                }
1058                if (!strcmp(arg, "--")) {
1059                        ok_paths = &argv[i+1];
1060                        break;
1061                } else if (arg[0] != '-') {
1062                        ok_paths = &argv[i];
1063                        break;
1064                }
1065
1066                usage(daemon_usage);
1067        }
1068
1069        if (log_syslog) {
1070                openlog("git-daemon", LOG_PID, LOG_DAEMON);
1071                set_die_routine(daemon_die);
1072        } else
1073                /* avoid splitting a message in the middle */
1074                setvbuf(stderr, NULL, _IOLBF, 0);
1075
1076        if (inetd_mode && (group_name || user_name))
1077                die("--user and --group are incompatible with --inetd");
1078
1079        if (inetd_mode && (listen_port || listen_addr))
1080                die("--listen= and --port= are incompatible with --inetd");
1081        else if (listen_port == 0)
1082                listen_port = DEFAULT_GIT_PORT;
1083
1084        if (group_name && !user_name)
1085                die("--group supplied without --user");
1086
1087        if (user_name) {
1088                pass = getpwnam(user_name);
1089                if (!pass)
1090                        die("user not found - %s", user_name);
1091
1092                if (!group_name)
1093                        gid = pass->pw_gid;
1094                else {
1095                        group = getgrnam(group_name);
1096                        if (!group)
1097                                die("group not found - %s", group_name);
1098
1099                        gid = group->gr_gid;
1100                }
1101        }
1102
1103        if (strict_paths && (!ok_paths || !*ok_paths))
1104                die("option --strict-paths requires a whitelist");
1105
1106        if (base_path && !is_directory(base_path))
1107                die("base-path '%s' does not exist or is not a directory",
1108                    base_path);
1109
1110        if (inetd_mode) {
1111                struct sockaddr_storage ss;
1112                struct sockaddr *peer = (struct sockaddr *)&ss;
1113                socklen_t slen = sizeof(ss);
1114
1115                if (!freopen("/dev/null", "w", stderr))
1116                        die_errno("failed to redirect stderr to /dev/null");
1117
1118                if (getpeername(0, peer, &slen))
1119                        peer = NULL;
1120
1121                return execute(peer);
1122        }
1123
1124        if (detach) {
1125                daemonize();
1126                loginfo("Ready to rumble");
1127        }
1128        else
1129                sanitize_stdfds();
1130
1131        if (pid_file)
1132                store_pid(pid_file);
1133
1134        return serve(listen_addr, listen_port, pass, gid);
1135}