Andrew's git / gitweb.git / daemon.c
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daemon.con commit Do not link with -lcrypto under NO_OPENSSL (5b02b9b)
   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[6];
 145
 146                dict[0].placeholder = "H"; dict[0].value = hostname;
 147                dict[1].placeholder = "CH"; dict[1].value = canon_hostname;
 148                dict[2].placeholder = "IP"; dict[2].value = ip_address;
 149                dict[3].placeholder = "P"; dict[3].value = tcp_port;
 150                dict[4].placeholder = "D"; dict[4].value = directory;
 151                dict[5].placeholder = NULL; dict[5].value = NULL;
 152                if (*dir != '/') {
 153                        /* Allow only absolute */
 154                        logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 155                        return NULL;
 156                }
 157
 158                strbuf_expand(&expanded_path, interpolated_path,
 159                                strbuf_expand_dict_cb, &dict);
 160                strlcpy(interp_path, expanded_path.buf, PATH_MAX);
 161                strbuf_release(&expanded_path);
 162                loginfo("Interpolated dir '%s'", interp_path);
 163
 164                dir = interp_path;
 165        }
 166        else if (base_path) {
 167                if (*dir != '/') {
 168                        /* Allow only absolute */
 169                        logerror("'%s': Non-absolute path denied (base-path active)", dir);
 170                        return NULL;
 171                }
 172                snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
 173                dir = rpath;
 174        }
 175
 176        path = enter_repo(dir, strict_paths);
 177        if (!path && base_path && base_path_relaxed) {
 178                /*
 179                 * if we fail and base_path_relaxed is enabled, try without
 180                 * prefixing the base path
 181                 */
 182                dir = directory;
 183                path = enter_repo(dir, strict_paths);
 184        }
 185
 186        if (!path) {
 187                logerror("'%s' does not appear to be a git repository", dir);
 188                return NULL;
 189        }
 190
 191        if ( ok_paths && *ok_paths ) {
 192                char **pp;
 193                int pathlen = strlen(path);
 194
 195                /* The validation is done on the paths after enter_repo
 196                 * appends optional {.git,.git/.git} and friends, but
 197                 * it does not use getcwd().  So if your /pub is
 198                 * a symlink to /mnt/pub, you can whitelist /pub and
 199                 * do not have to say /mnt/pub.
 200                 * Do not say /pub/.
 201                 */
 202                for ( pp = ok_paths ; *pp ; pp++ ) {
 203                        int len = strlen(*pp);
 204                        if (len <= pathlen &&
 205                            !memcmp(*pp, path, len) &&
 206                            (path[len] == '\0' ||
 207                             (!strict_paths && path[len] == '/')))
 208                                return path;
 209                }
 210        }
 211        else {
 212                /* be backwards compatible */
 213                if (!strict_paths)
 214                        return path;
 215        }
 216
 217        logerror("'%s': not in whitelist", path);
 218        return NULL;            /* Fallthrough. Deny by default */
 219}
 220
 221typedef int (*daemon_service_fn)(void);
 222struct daemon_service {
 223        const char *name;
 224        const char *config_name;
 225        daemon_service_fn fn;
 226        int enabled;
 227        int overridable;
 228};
 229
 230static struct daemon_service *service_looking_at;
 231static int service_enabled;
 232
 233static int git_daemon_config(const char *var, const char *value, void *cb)
 234{
 235        if (!prefixcmp(var, "daemon.") &&
 236            !strcmp(var + 7, service_looking_at->config_name)) {
 237                service_enabled = git_config_bool(var, value);
 238                return 0;
 239        }
 240
 241        /* we are not interested in parsing any other configuration here */
 242        return 0;
 243}
 244
 245static int run_service(char *dir, struct daemon_service *service)
 246{
 247        const char *path;
 248        int enabled = service->enabled;
 249
 250        loginfo("Request %s for '%s'", service->name, dir);
 251
 252        if (!enabled && !service->overridable) {
 253                logerror("'%s': service not enabled.", service->name);
 254                errno = EACCES;
 255                return -1;
 256        }
 257
 258        if (!(path = path_ok(dir)))
 259                return -1;
 260
 261        /*
 262         * Security on the cheap.
 263         *
 264         * We want a readable HEAD, usable "objects" directory, and
 265         * a "git-daemon-export-ok" flag that says that the other side
 266         * is ok with us doing this.
 267         *
 268         * path_ok() uses enter_repo() and does whitelist checking.
 269         * We only need to make sure the repository is exported.
 270         */
 271
 272        if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 273                logerror("'%s': repository not exported.", path);
 274                errno = EACCES;
 275                return -1;
 276        }
 277
 278        if (service->overridable) {
 279                service_looking_at = service;
 280                service_enabled = -1;
 281                git_config(git_daemon_config, NULL);
 282                if (0 <= service_enabled)
 283                        enabled = service_enabled;
 284        }
 285        if (!enabled) {
 286                logerror("'%s': service not enabled for '%s'",
 287                         service->name, path);
 288                errno = EACCES;
 289                return -1;
 290        }
 291
 292        /*
 293         * We'll ignore SIGTERM from now on, we have a
 294         * good client.
 295         */
 296        signal(SIGTERM, SIG_IGN);
 297
 298        return service->fn();
 299}
 300
 301static void copy_to_log(int fd)
 302{
 303        struct strbuf line = STRBUF_INIT;
 304        FILE *fp;
 305
 306        fp = fdopen(fd, "r");
 307        if (fp == NULL) {
 308                logerror("fdopen of error channel failed");
 309                close(fd);
 310                return;
 311        }
 312
 313        while (strbuf_getline(&line, fp, '\n') != EOF) {
 314                logerror("%s", line.buf);
 315                strbuf_setlen(&line, 0);
 316        }
 317
 318        strbuf_release(&line);
 319        fclose(fp);
 320}
 321
 322static int run_service_command(const char **argv)
 323{
 324        struct child_process cld;
 325
 326        memset(&cld, 0, sizeof(cld));
 327        cld.argv = argv;
 328        cld.git_cmd = 1;
 329        cld.err = -1;
 330        if (start_command(&cld))
 331                return -1;
 332
 333        close(0);
 334        close(1);
 335
 336        copy_to_log(cld.err);
 337
 338        return finish_command(&cld);
 339}
 340
 341static int upload_pack(void)
 342{
 343        /* Timeout as string */
 344        char timeout_buf[64];
 345        const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
 346
 347        argv[2] = timeout_buf;
 348
 349        snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 350        return run_service_command(argv);
 351}
 352
 353static int upload_archive(void)
 354{
 355        static const char *argv[] = { "upload-archive", ".", NULL };
 356        return run_service_command(argv);
 357}
 358
 359static int receive_pack(void)
 360{
 361        static const char *argv[] = { "receive-pack", ".", NULL };
 362        return run_service_command(argv);
 363}
 364
 365static struct daemon_service daemon_service[] = {
 366        { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 367        { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 368        { "receive-pack", "receivepack", receive_pack, 0, 1 },
 369};
 370
 371static void enable_service(const char *name, int ena)
 372{
 373        int i;
 374        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 375                if (!strcmp(daemon_service[i].name, name)) {
 376                        daemon_service[i].enabled = ena;
 377                        return;
 378                }
 379        }
 380        die("No such service %s", name);
 381}
 382
 383static void make_service_overridable(const char *name, int ena)
 384{
 385        int i;
 386        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 387                if (!strcmp(daemon_service[i].name, name)) {
 388                        daemon_service[i].overridable = ena;
 389                        return;
 390                }
 391        }
 392        die("No such service %s", name);
 393}
 394
 395static char *xstrdup_tolower(const char *str)
 396{
 397        char *p, *dup = xstrdup(str);
 398        for (p = dup; *p; p++)
 399                *p = tolower(*p);
 400        return dup;
 401}
 402
 403static void parse_host_and_port(char *hostport, char **host,
 404        char **port)
 405{
 406        if (*hostport == '[') {
 407                char *end;
 408
 409                end = strchr(hostport, ']');
 410                if (!end)
 411                        die("Invalid request ('[' without ']')");
 412                *end = '\0';
 413                *host = hostport + 1;
 414                if (!end[1])
 415                        *port = NULL;
 416                else if (end[1] == ':')
 417                        *port = end + 2;
 418                else
 419                        die("Garbage after end of host part");
 420        } else {
 421                *host = hostport;
 422                *port = strrchr(hostport, ':');
 423                if (*port) {
 424                        **port = '\0';
 425                        ++*port;
 426                }
 427        }
 428}
 429
 430/*
 431 * Read the host as supplied by the client connection.
 432 */
 433static void parse_host_arg(char *extra_args, int buflen)
 434{
 435        char *val;
 436        int vallen;
 437        char *end = extra_args + buflen;
 438
 439        if (extra_args < end && *extra_args) {
 440                saw_extended_args = 1;
 441                if (strncasecmp("host=", extra_args, 5) == 0) {
 442                        val = extra_args + 5;
 443                        vallen = strlen(val) + 1;
 444                        if (*val) {
 445                                /* Split <host>:<port> at colon. */
 446                                char *host;
 447                                char *port;
 448                                parse_host_and_port(val, &host, &port);
 449                                if (port) {
 450                                        free(tcp_port);
 451                                        tcp_port = xstrdup(port);
 452                                }
 453                                free(hostname);
 454                                hostname = xstrdup_tolower(host);
 455                        }
 456
 457                        /* On to the next one */
 458                        extra_args = val + vallen;
 459                }
 460                if (extra_args < end && *extra_args)
 461                        die("Invalid request");
 462        }
 463
 464        /*
 465         * Locate canonical hostname and its IP address.
 466         */
 467        if (hostname) {
 468#ifndef NO_IPV6
 469                struct addrinfo hints;
 470                struct addrinfo *ai;
 471                int gai;
 472                static char addrbuf[HOST_NAME_MAX + 1];
 473
 474                memset(&hints, 0, sizeof(hints));
 475                hints.ai_flags = AI_CANONNAME;
 476
 477                gai = getaddrinfo(hostname, NULL, &hints, &ai);
 478                if (!gai) {
 479                        struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 480
 481                        inet_ntop(AF_INET, &sin_addr->sin_addr,
 482                                  addrbuf, sizeof(addrbuf));
 483                        free(ip_address);
 484                        ip_address = xstrdup(addrbuf);
 485
 486                        free(canon_hostname);
 487                        canon_hostname = xstrdup(ai->ai_canonname ?
 488                                                 ai->ai_canonname : ip_address);
 489
 490                        freeaddrinfo(ai);
 491                }
 492#else
 493                struct hostent *hent;
 494                struct sockaddr_in sa;
 495                char **ap;
 496                static char addrbuf[HOST_NAME_MAX + 1];
 497
 498                hent = gethostbyname(hostname);
 499
 500                ap = hent->h_addr_list;
 501                memset(&sa, 0, sizeof sa);
 502                sa.sin_family = hent->h_addrtype;
 503                sa.sin_port = htons(0);
 504                memcpy(&sa.sin_addr, *ap, hent->h_length);
 505
 506                inet_ntop(hent->h_addrtype, &sa.sin_addr,
 507                          addrbuf, sizeof(addrbuf));
 508
 509                free(canon_hostname);
 510                canon_hostname = xstrdup(hent->h_name);
 511                free(ip_address);
 512                ip_address = xstrdup(addrbuf);
 513#endif
 514        }
 515}
 516
 517
 518static int execute(struct sockaddr *addr)
 519{
 520        static char line[1000];
 521        int pktlen, len, i;
 522
 523        if (addr) {
 524                char addrbuf[256] = "";
 525                int port = -1;
 526
 527                if (addr->sa_family == AF_INET) {
 528                        struct sockaddr_in *sin_addr = (void *) addr;
 529                        inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
 530                        port = ntohs(sin_addr->sin_port);
 531#ifndef NO_IPV6
 532                } else if (addr && addr->sa_family == AF_INET6) {
 533                        struct sockaddr_in6 *sin6_addr = (void *) addr;
 534
 535                        char *buf = addrbuf;
 536                        *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 537                        inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
 538                        strcat(buf, "]");
 539
 540                        port = ntohs(sin6_addr->sin6_port);
 541#endif
 542                }
 543                loginfo("Connection from %s:%d", addrbuf, port);
 544                setenv("REMOTE_ADDR", addrbuf, 1);
 545        }
 546        else {
 547                unsetenv("REMOTE_ADDR");
 548        }
 549
 550        alarm(init_timeout ? init_timeout : timeout);
 551        pktlen = packet_read_line(0, line, sizeof(line));
 552        alarm(0);
 553
 554        len = strlen(line);
 555        if (pktlen != len)
 556                loginfo("Extended attributes (%d bytes) exist <%.*s>",
 557                        (int) pktlen - len,
 558                        (int) pktlen - len, line + len + 1);
 559        if (len && line[len-1] == '\n') {
 560                line[--len] = 0;
 561                pktlen--;
 562        }
 563
 564        free(hostname);
 565        free(canon_hostname);
 566        free(ip_address);
 567        free(tcp_port);
 568        hostname = canon_hostname = ip_address = tcp_port = NULL;
 569
 570        if (len != pktlen)
 571                parse_host_arg(line + len + 1, pktlen - len - 1);
 572
 573        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 574                struct daemon_service *s = &(daemon_service[i]);
 575                int namelen = strlen(s->name);
 576                if (!prefixcmp(line, "git-") &&
 577                    !strncmp(s->name, line + 4, namelen) &&
 578                    line[namelen + 4] == ' ') {
 579                        /*
 580                         * Note: The directory here is probably context sensitive,
 581                         * and might depend on the actual service being performed.
 582                         */
 583                        return run_service(line + namelen + 5, s);
 584                }
 585        }
 586
 587        logerror("Protocol error: '%s'", line);
 588        return -1;
 589}
 590
 591static int addrcmp(const struct sockaddr_storage *s1,
 592    const struct sockaddr_storage *s2)
 593{
 594        const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 595        const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 596
 597        if (sa1->sa_family != sa2->sa_family)
 598                return sa1->sa_family - sa2->sa_family;
 599        if (sa1->sa_family == AF_INET)
 600                return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 601                    &((struct sockaddr_in *)s2)->sin_addr,
 602                    sizeof(struct in_addr));
 603#ifndef NO_IPV6
 604        if (sa1->sa_family == AF_INET6)
 605                return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 606                    &((struct sockaddr_in6 *)s2)->sin6_addr,
 607                    sizeof(struct in6_addr));
 608#endif
 609        return 0;
 610}
 611
 612static int max_connections = 32;
 613
 614static unsigned int live_children;
 615
 616static struct child {
 617        struct child *next;
 618        pid_t pid;
 619        struct sockaddr_storage address;
 620} *firstborn;
 621
 622static void add_child(pid_t pid, struct sockaddr *addr, int addrlen)
 623{
 624        struct child *newborn, **cradle;
 625
 626        newborn = xcalloc(1, sizeof(*newborn));
 627        live_children++;
 628        newborn->pid = pid;
 629        memcpy(&newborn->address, addr, addrlen);
 630        for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 631                if (!addrcmp(&(*cradle)->address, &newborn->address))
 632                        break;
 633        newborn->next = *cradle;
 634        *cradle = newborn;
 635}
 636
 637static void remove_child(pid_t pid)
 638{
 639        struct child **cradle, *blanket;
 640
 641        for (cradle = &firstborn; (blanket = *cradle); cradle = &blanket->next)
 642                if (blanket->pid == pid) {
 643                        *cradle = blanket->next;
 644                        live_children--;
 645                        free(blanket);
 646                        break;
 647                }
 648}
 649
 650/*
 651 * This gets called if the number of connections grows
 652 * past "max_connections".
 653 *
 654 * We kill the newest connection from a duplicate IP.
 655 */
 656static void kill_some_child(void)
 657{
 658        const struct child *blanket, *next;
 659
 660        if (!(blanket = firstborn))
 661                return;
 662
 663        for (; (next = blanket->next); blanket = next)
 664                if (!addrcmp(&blanket->address, &next->address)) {
 665                        kill(blanket->pid, SIGTERM);
 666                        break;
 667                }
 668}
 669
 670static void check_dead_children(void)
 671{
 672        int status;
 673        pid_t pid;
 674
 675        while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
 676                const char *dead = "";
 677                remove_child(pid);
 678                if (!WIFEXITED(status) || (WEXITSTATUS(status) > 0))
 679                        dead = " (with error)";
 680                loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 681        }
 682}
 683
 684static void handle(int incoming, struct sockaddr *addr, int addrlen)
 685{
 686        pid_t pid;
 687
 688        if (max_connections && live_children >= max_connections) {
 689                kill_some_child();
 690                sleep(1);  /* give it some time to die */
 691                check_dead_children();
 692                if (live_children >= max_connections) {
 693                        close(incoming);
 694                        logerror("Too many children, dropping connection");
 695                        return;
 696                }
 697        }
 698
 699        if ((pid = fork())) {
 700                close(incoming);
 701                if (pid < 0) {
 702                        logerror("Couldn't fork %s", strerror(errno));
 703                        return;
 704                }
 705
 706                add_child(pid, addr, addrlen);
 707                return;
 708        }
 709
 710        dup2(incoming, 0);
 711        dup2(incoming, 1);
 712        close(incoming);
 713
 714        exit(execute(addr));
 715}
 716
 717static void child_handler(int signo)
 718{
 719        /*
 720         * Otherwise empty handler because systemcalls will get interrupted
 721         * upon signal receipt
 722         * SysV needs the handler to be rearmed
 723         */
 724        signal(SIGCHLD, child_handler);
 725}
 726
 727static int set_reuse_addr(int sockfd)
 728{
 729        int on = 1;
 730
 731        if (!reuseaddr)
 732                return 0;
 733        return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 734                          &on, sizeof(on));
 735}
 736
 737#ifndef NO_IPV6
 738
 739static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 740{
 741        int socknum = 0, *socklist = NULL;
 742        int maxfd = -1;
 743        char pbuf[NI_MAXSERV];
 744        struct addrinfo hints, *ai0, *ai;
 745        int gai;
 746        long flags;
 747
 748        sprintf(pbuf, "%d", listen_port);
 749        memset(&hints, 0, sizeof(hints));
 750        hints.ai_family = AF_UNSPEC;
 751        hints.ai_socktype = SOCK_STREAM;
 752        hints.ai_protocol = IPPROTO_TCP;
 753        hints.ai_flags = AI_PASSIVE;
 754
 755        gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 756        if (gai)
 757                die("getaddrinfo() failed: %s", gai_strerror(gai));
 758
 759        for (ai = ai0; ai; ai = ai->ai_next) {
 760                int sockfd;
 761
 762                sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 763                if (sockfd < 0)
 764                        continue;
 765                if (sockfd >= FD_SETSIZE) {
 766                        logerror("Socket descriptor too large");
 767                        close(sockfd);
 768                        continue;
 769                }
 770
 771#ifdef IPV6_V6ONLY
 772                if (ai->ai_family == AF_INET6) {
 773                        int on = 1;
 774                        setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 775                                   &on, sizeof(on));
 776                        /* Note: error is not fatal */
 777                }
 778#endif
 779
 780                if (set_reuse_addr(sockfd)) {
 781                        close(sockfd);
 782                        continue;
 783                }
 784
 785                if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 786                        close(sockfd);
 787                        continue;       /* not fatal */
 788                }
 789                if (listen(sockfd, 5) < 0) {
 790                        close(sockfd);
 791                        continue;       /* not fatal */
 792                }
 793
 794                flags = fcntl(sockfd, F_GETFD, 0);
 795                if (flags >= 0)
 796                        fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 797
 798                socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
 799                socklist[socknum++] = sockfd;
 800
 801                if (maxfd < sockfd)
 802                        maxfd = sockfd;
 803        }
 804
 805        freeaddrinfo(ai0);
 806
 807        *socklist_p = socklist;
 808        return socknum;
 809}
 810
 811#else /* NO_IPV6 */
 812
 813static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 814{
 815        struct sockaddr_in sin;
 816        int sockfd;
 817        long flags;
 818
 819        memset(&sin, 0, sizeof sin);
 820        sin.sin_family = AF_INET;
 821        sin.sin_port = htons(listen_port);
 822
 823        if (listen_addr) {
 824                /* Well, host better be an IP address here. */
 825                if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 826                        return 0;
 827        } else {
 828                sin.sin_addr.s_addr = htonl(INADDR_ANY);
 829        }
 830
 831        sockfd = socket(AF_INET, SOCK_STREAM, 0);
 832        if (sockfd < 0)
 833                return 0;
 834
 835        if (set_reuse_addr(sockfd)) {
 836                close(sockfd);
 837                return 0;
 838        }
 839
 840        if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 841                close(sockfd);
 842                return 0;
 843        }
 844
 845        if (listen(sockfd, 5) < 0) {
 846                close(sockfd);
 847                return 0;
 848        }
 849
 850        flags = fcntl(sockfd, F_GETFD, 0);
 851        if (flags >= 0)
 852                fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 853
 854        *socklist_p = xmalloc(sizeof(int));
 855        **socklist_p = sockfd;
 856        return 1;
 857}
 858
 859#endif
 860
 861static int service_loop(int socknum, int *socklist)
 862{
 863        struct pollfd *pfd;
 864        int i;
 865
 866        pfd = xcalloc(socknum, sizeof(struct pollfd));
 867
 868        for (i = 0; i < socknum; i++) {
 869                pfd[i].fd = socklist[i];
 870                pfd[i].events = POLLIN;
 871        }
 872
 873        signal(SIGCHLD, child_handler);
 874
 875        for (;;) {
 876                int i;
 877
 878                check_dead_children();
 879
 880                if (poll(pfd, socknum, -1) < 0) {
 881                        if (errno != EINTR) {
 882                                logerror("Poll failed, resuming: %s",
 883                                      strerror(errno));
 884                                sleep(1);
 885                        }
 886                        continue;
 887                }
 888
 889                for (i = 0; i < socknum; i++) {
 890                        if (pfd[i].revents & POLLIN) {
 891                                struct sockaddr_storage ss;
 892                                unsigned int sslen = sizeof(ss);
 893                                int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
 894                                if (incoming < 0) {
 895                                        switch (errno) {
 896                                        case EAGAIN:
 897                                        case EINTR:
 898                                        case ECONNABORTED:
 899                                                continue;
 900                                        default:
 901                                                die_errno("accept returned");
 902                                        }
 903                                }
 904                                handle(incoming, (struct sockaddr *)&ss, sslen);
 905                        }
 906                }
 907        }
 908}
 909
 910/* if any standard file descriptor is missing open it to /dev/null */
 911static void sanitize_stdfds(void)
 912{
 913        int fd = open("/dev/null", O_RDWR, 0);
 914        while (fd != -1 && fd < 2)
 915                fd = dup(fd);
 916        if (fd == -1)
 917                die_errno("open /dev/null or dup failed");
 918        if (fd > 2)
 919                close(fd);
 920}
 921
 922static void daemonize(void)
 923{
 924        switch (fork()) {
 925                case 0:
 926                        break;
 927                case -1:
 928                        die_errno("fork failed");
 929                default:
 930                        exit(0);
 931        }
 932        if (setsid() == -1)
 933                die_errno("setsid failed");
 934        close(0);
 935        close(1);
 936        close(2);
 937        sanitize_stdfds();
 938}
 939
 940static void store_pid(const char *path)
 941{
 942        FILE *f = fopen(path, "w");
 943        if (!f)
 944                die_errno("cannot open pid file '%s'", path);
 945        if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
 946                die_errno("failed to write pid file '%s'", path);
 947}
 948
 949static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
 950{
 951        int socknum, *socklist;
 952
 953        socknum = socksetup(listen_addr, listen_port, &socklist);
 954        if (socknum == 0)
 955                die("unable to allocate any listen sockets on host %s port %u",
 956                    listen_addr, listen_port);
 957
 958        if (pass && gid &&
 959            (initgroups(pass->pw_name, gid) || setgid (gid) ||
 960             setuid(pass->pw_uid)))
 961                die("cannot drop privileges");
 962
 963        return service_loop(socknum, socklist);
 964}
 965
 966int main(int argc, char **argv)
 967{
 968        int listen_port = 0;
 969        char *listen_addr = NULL;
 970        int inetd_mode = 0;
 971        const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
 972        int detach = 0;
 973        struct passwd *pass = NULL;
 974        struct group *group;
 975        gid_t gid = 0;
 976        int i;
 977
 978        git_extract_argv0_path(argv[0]);
 979
 980        for (i = 1; i < argc; i++) {
 981                char *arg = argv[i];
 982
 983                if (!prefixcmp(arg, "--listen=")) {
 984                        listen_addr = xstrdup_tolower(arg + 9);
 985                        continue;
 986                }
 987                if (!prefixcmp(arg, "--port=")) {
 988                        char *end;
 989                        unsigned long n;
 990                        n = strtoul(arg+7, &end, 0);
 991                        if (arg[7] && !*end) {
 992                                listen_port = n;
 993                                continue;
 994                        }
 995                }
 996                if (!strcmp(arg, "--inetd")) {
 997                        inetd_mode = 1;
 998                        log_syslog = 1;
 999                        continue;
1000                }
1001                if (!strcmp(arg, "--verbose")) {
1002                        verbose = 1;
1003                        continue;
1004                }
1005                if (!strcmp(arg, "--syslog")) {
1006                        log_syslog = 1;
1007                        continue;
1008                }
1009                if (!strcmp(arg, "--export-all")) {
1010                        export_all_trees = 1;
1011                        continue;
1012                }
1013                if (!prefixcmp(arg, "--timeout=")) {
1014                        timeout = atoi(arg+10);
1015                        continue;
1016                }
1017                if (!prefixcmp(arg, "--init-timeout=")) {
1018                        init_timeout = atoi(arg+15);
1019                        continue;
1020                }
1021                if (!prefixcmp(arg, "--max-connections=")) {
1022                        max_connections = atoi(arg+18);
1023                        if (max_connections < 0)
1024                                max_connections = 0;            /* unlimited */
1025                        continue;
1026                }
1027                if (!strcmp(arg, "--strict-paths")) {
1028                        strict_paths = 1;
1029                        continue;
1030                }
1031                if (!prefixcmp(arg, "--base-path=")) {
1032                        base_path = arg+12;
1033                        continue;
1034                }
1035                if (!strcmp(arg, "--base-path-relaxed")) {
1036                        base_path_relaxed = 1;
1037                        continue;
1038                }
1039                if (!prefixcmp(arg, "--interpolated-path=")) {
1040                        interpolated_path = arg+20;
1041                        continue;
1042                }
1043                if (!strcmp(arg, "--reuseaddr")) {
1044                        reuseaddr = 1;
1045                        continue;
1046                }
1047                if (!strcmp(arg, "--user-path")) {
1048                        user_path = "";
1049                        continue;
1050                }
1051                if (!prefixcmp(arg, "--user-path=")) {
1052                        user_path = arg + 12;
1053                        continue;
1054                }
1055                if (!prefixcmp(arg, "--pid-file=")) {
1056                        pid_file = arg + 11;
1057                        continue;
1058                }
1059                if (!strcmp(arg, "--detach")) {
1060                        detach = 1;
1061                        log_syslog = 1;
1062                        continue;
1063                }
1064                if (!prefixcmp(arg, "--user=")) {
1065                        user_name = arg + 7;
1066                        continue;
1067                }
1068                if (!prefixcmp(arg, "--group=")) {
1069                        group_name = arg + 8;
1070                        continue;
1071                }
1072                if (!prefixcmp(arg, "--enable=")) {
1073                        enable_service(arg + 9, 1);
1074                        continue;
1075                }
1076                if (!prefixcmp(arg, "--disable=")) {
1077                        enable_service(arg + 10, 0);
1078                        continue;
1079                }
1080                if (!prefixcmp(arg, "--allow-override=")) {
1081                        make_service_overridable(arg + 17, 1);
1082                        continue;
1083                }
1084                if (!prefixcmp(arg, "--forbid-override=")) {
1085                        make_service_overridable(arg + 18, 0);
1086                        continue;
1087                }
1088                if (!strcmp(arg, "--")) {
1089                        ok_paths = &argv[i+1];
1090                        break;
1091                } else if (arg[0] != '-') {
1092                        ok_paths = &argv[i];
1093                        break;
1094                }
1095
1096                usage(daemon_usage);
1097        }
1098
1099        if (log_syslog) {
1100                openlog("git-daemon", LOG_PID, LOG_DAEMON);
1101                set_die_routine(daemon_die);
1102        } else
1103                /* avoid splitting a message in the middle */
1104                setvbuf(stderr, NULL, _IOLBF, 0);
1105
1106        if (inetd_mode && (group_name || user_name))
1107                die("--user and --group are incompatible with --inetd");
1108
1109        if (inetd_mode && (listen_port || listen_addr))
1110                die("--listen= and --port= are incompatible with --inetd");
1111        else if (listen_port == 0)
1112                listen_port = DEFAULT_GIT_PORT;
1113
1114        if (group_name && !user_name)
1115                die("--group supplied without --user");
1116
1117        if (user_name) {
1118                pass = getpwnam(user_name);
1119                if (!pass)
1120                        die("user not found - %s", user_name);
1121
1122                if (!group_name)
1123                        gid = pass->pw_gid;
1124                else {
1125                        group = getgrnam(group_name);
1126                        if (!group)
1127                                die("group not found - %s", group_name);
1128
1129                        gid = group->gr_gid;
1130                }
1131        }
1132
1133        if (strict_paths && (!ok_paths || !*ok_paths))
1134                die("option --strict-paths requires a whitelist");
1135
1136        if (base_path && !is_directory(base_path))
1137                die("base-path '%s' does not exist or is not a directory",
1138                    base_path);
1139
1140        if (inetd_mode) {
1141                struct sockaddr_storage ss;
1142                struct sockaddr *peer = (struct sockaddr *)&ss;
1143                socklen_t slen = sizeof(ss);
1144
1145                if (!freopen("/dev/null", "w", stderr))
1146                        die_errno("failed to redirect stderr to /dev/null");
1147
1148                if (getpeername(0, peer, &slen))
1149                        peer = NULL;
1150
1151                return execute(peer);
1152        }
1153
1154        if (detach) {
1155                daemonize();
1156                loginfo("Ready to rumble");
1157        }
1158        else
1159                sanitize_stdfds();
1160
1161        if (pid_file)
1162                store_pid(pid_file);
1163
1164        return serve(listen_addr, listen_port, pass, gid);
1165}