Andrew's git / gitweb.git / daemon.c
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daemon.con commit Make sure fsck_commit_buffer() does not run out of the buffer (4d0d897)
   1#include "cache.h"
   2#include "pkt-line.h"
   3#include "exec_cmd.h"
   4#include "run-command.h"
   5#include "strbuf.h"
   6#include "string-list.h"
   7
   8#ifndef HOST_NAME_MAX
   9#define HOST_NAME_MAX 256
  10#endif
  11
  12#ifdef NO_INITGROUPS
  13#define initgroups(x, y) (0) /* nothing */
  14#endif
  15
  16static int log_syslog;
  17static int verbose;
  18static int reuseaddr;
  19static int informative_errors;
  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] [--pid-file=<file>]\n"
  28"           [--(enable|disable|allow-override|forbid-override)=<service>]\n"
  29"           [--access-hook=<path>]\n"
  30"           [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
  31"                      [--detach] [--user=<user> [--group=<group>]]\n"
  32"           [<directory>...]";
  33
  34/* List of acceptable pathname prefixes */
  35static char **ok_paths;
  36static int strict_paths;
  37
  38/* If this is set, git-daemon-export-ok is not required */
  39static int export_all_trees;
  40
  41/* Take all paths relative to this one if non-NULL */
  42static const char *base_path;
  43static const char *interpolated_path;
  44static int base_path_relaxed;
  45
  46/* Flag indicating client sent extra args. */
  47static int saw_extended_args;
  48
  49/* If defined, ~user notation is allowed and the string is inserted
  50 * after ~user/.  E.g. a request to git://host/~alice/frotz would
  51 * go to /home/alice/pub_git/frotz with --user-path=pub_git.
  52 */
  53static const char *user_path;
  54
  55/* Timeout, and initial timeout */
  56static unsigned int timeout;
  57static unsigned int init_timeout;
  58
  59static char *hostname;
  60static char *canon_hostname;
  61static char *ip_address;
  62static char *tcp_port;
  63
  64static void logreport(int priority, const char *err, va_list params)
  65{
  66        if (log_syslog) {
  67                char buf[1024];
  68                vsnprintf(buf, sizeof(buf), err, params);
  69                syslog(priority, "%s", buf);
  70        } else {
  71                /*
  72                 * Since stderr is set to buffered mode, the
  73                 * logging of different processes will not overlap
  74                 * unless they overflow the (rather big) buffers.
  75                 */
  76                fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
  77                vfprintf(stderr, err, params);
  78                fputc('\n', stderr);
  79                fflush(stderr);
  80        }
  81}
  82
  83__attribute__((format (printf, 1, 2)))
  84static void logerror(const char *err, ...)
  85{
  86        va_list params;
  87        va_start(params, err);
  88        logreport(LOG_ERR, err, params);
  89        va_end(params);
  90}
  91
  92__attribute__((format (printf, 1, 2)))
  93static void loginfo(const char *err, ...)
  94{
  95        va_list params;
  96        if (!verbose)
  97                return;
  98        va_start(params, err);
  99        logreport(LOG_INFO, err, params);
 100        va_end(params);
 101}
 102
 103static void NORETURN daemon_die(const char *err, va_list params)
 104{
 105        logreport(LOG_ERR, err, params);
 106        exit(1);
 107}
 108
 109static const char *path_ok(const char *directory)
 110{
 111        static char rpath[PATH_MAX];
 112        static char interp_path[PATH_MAX];
 113        const char *path;
 114        const char *dir;
 115
 116        dir = directory;
 117
 118        if (daemon_avoid_alias(dir)) {
 119                logerror("'%s': aliased", dir);
 120                return NULL;
 121        }
 122
 123        if (*dir == '~') {
 124                if (!user_path) {
 125                        logerror("'%s': User-path not allowed", dir);
 126                        return NULL;
 127                }
 128                if (*user_path) {
 129                        /* Got either "~alice" or "~alice/foo";
 130                         * rewrite them to "~alice/%s" or
 131                         * "~alice/%s/foo".
 132                         */
 133                        int namlen, restlen = strlen(dir);
 134                        const char *slash = strchr(dir, '/');
 135                        if (!slash)
 136                                slash = dir + restlen;
 137                        namlen = slash - dir;
 138                        restlen -= namlen;
 139                        loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
 140                        snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
 141                                 namlen, dir, user_path, restlen, slash);
 142                        dir = rpath;
 143                }
 144        }
 145        else if (interpolated_path && saw_extended_args) {
 146                struct strbuf expanded_path = STRBUF_INIT;
 147                struct strbuf_expand_dict_entry dict[6];
 148
 149                dict[0].placeholder = "H"; dict[0].value = hostname;
 150                dict[1].placeholder = "CH"; dict[1].value = canon_hostname;
 151                dict[2].placeholder = "IP"; dict[2].value = ip_address;
 152                dict[3].placeholder = "P"; dict[3].value = tcp_port;
 153                dict[4].placeholder = "D"; dict[4].value = directory;
 154                dict[5].placeholder = NULL; dict[5].value = NULL;
 155                if (*dir != '/') {
 156                        /* Allow only absolute */
 157                        logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 158                        return NULL;
 159                }
 160
 161                strbuf_expand(&expanded_path, interpolated_path,
 162                                strbuf_expand_dict_cb, &dict);
 163                strlcpy(interp_path, expanded_path.buf, PATH_MAX);
 164                strbuf_release(&expanded_path);
 165                loginfo("Interpolated dir '%s'", interp_path);
 166
 167                dir = interp_path;
 168        }
 169        else if (base_path) {
 170                if (*dir != '/') {
 171                        /* Allow only absolute */
 172                        logerror("'%s': Non-absolute path denied (base-path active)", dir);
 173                        return NULL;
 174                }
 175                snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
 176                dir = rpath;
 177        }
 178
 179        path = enter_repo(dir, strict_paths);
 180        if (!path && base_path && base_path_relaxed) {
 181                /*
 182                 * if we fail and base_path_relaxed is enabled, try without
 183                 * prefixing the base path
 184                 */
 185                dir = directory;
 186                path = enter_repo(dir, strict_paths);
 187        }
 188
 189        if (!path) {
 190                logerror("'%s' does not appear to be a git repository", dir);
 191                return NULL;
 192        }
 193
 194        if ( ok_paths && *ok_paths ) {
 195                char **pp;
 196                int pathlen = strlen(path);
 197
 198                /* The validation is done on the paths after enter_repo
 199                 * appends optional {.git,.git/.git} and friends, but
 200                 * it does not use getcwd().  So if your /pub is
 201                 * a symlink to /mnt/pub, you can whitelist /pub and
 202                 * do not have to say /mnt/pub.
 203                 * Do not say /pub/.
 204                 */
 205                for ( pp = ok_paths ; *pp ; pp++ ) {
 206                        int len = strlen(*pp);
 207                        if (len <= pathlen &&
 208                            !memcmp(*pp, path, len) &&
 209                            (path[len] == '\0' ||
 210                             (!strict_paths && path[len] == '/')))
 211                                return path;
 212                }
 213        }
 214        else {
 215                /* be backwards compatible */
 216                if (!strict_paths)
 217                        return path;
 218        }
 219
 220        logerror("'%s': not in whitelist", path);
 221        return NULL;            /* Fallthrough. Deny by default */
 222}
 223
 224typedef int (*daemon_service_fn)(void);
 225struct daemon_service {
 226        const char *name;
 227        const char *config_name;
 228        daemon_service_fn fn;
 229        int enabled;
 230        int overridable;
 231};
 232
 233static struct daemon_service *service_looking_at;
 234static int service_enabled;
 235
 236static int git_daemon_config(const char *var, const char *value, void *cb)
 237{
 238        const char *service;
 239
 240        if (skip_prefix(var, "daemon.", &service) &&
 241            !strcmp(service, service_looking_at->config_name)) {
 242                service_enabled = git_config_bool(var, value);
 243                return 0;
 244        }
 245
 246        /* we are not interested in parsing any other configuration here */
 247        return 0;
 248}
 249
 250static int daemon_error(const char *dir, const char *msg)
 251{
 252        if (!informative_errors)
 253                msg = "access denied or repository not exported";
 254        packet_write(1, "ERR %s: %s", msg, dir);
 255        return -1;
 256}
 257
 258static const char *access_hook;
 259
 260static int run_access_hook(struct daemon_service *service, const char *dir, const char *path)
 261{
 262        struct child_process child;
 263        struct strbuf buf = STRBUF_INIT;
 264        const char *argv[8];
 265        const char **arg = argv;
 266        char *eol;
 267        int seen_errors = 0;
 268
 269#define STRARG(x) ((x) ? (x) : "")
 270        *arg++ = access_hook;
 271        *arg++ = service->name;
 272        *arg++ = path;
 273        *arg++ = STRARG(hostname);
 274        *arg++ = STRARG(canon_hostname);
 275        *arg++ = STRARG(ip_address);
 276        *arg++ = STRARG(tcp_port);
 277        *arg = NULL;
 278#undef STRARG
 279
 280        memset(&child, 0, sizeof(child));
 281        child.use_shell = 1;
 282        child.argv = argv;
 283        child.no_stdin = 1;
 284        child.no_stderr = 1;
 285        child.out = -1;
 286        if (start_command(&child)) {
 287                logerror("daemon access hook '%s' failed to start",
 288                         access_hook);
 289                goto error_return;
 290        }
 291        if (strbuf_read(&buf, child.out, 0) < 0) {
 292                logerror("failed to read from pipe to daemon access hook '%s'",
 293                         access_hook);
 294                strbuf_reset(&buf);
 295                seen_errors = 1;
 296        }
 297        if (close(child.out) < 0) {
 298                logerror("failed to close pipe to daemon access hook '%s'",
 299                         access_hook);
 300                seen_errors = 1;
 301        }
 302        if (finish_command(&child))
 303                seen_errors = 1;
 304
 305        if (!seen_errors) {
 306                strbuf_release(&buf);
 307                return 0;
 308        }
 309
 310error_return:
 311        strbuf_ltrim(&buf);
 312        if (!buf.len)
 313                strbuf_addstr(&buf, "service rejected");
 314        eol = strchr(buf.buf, '\n');
 315        if (eol)
 316                *eol = '\0';
 317        errno = EACCES;
 318        daemon_error(dir, buf.buf);
 319        strbuf_release(&buf);
 320        return -1;
 321}
 322
 323static int run_service(const char *dir, struct daemon_service *service)
 324{
 325        const char *path;
 326        int enabled = service->enabled;
 327
 328        loginfo("Request %s for '%s'", service->name, dir);
 329
 330        if (!enabled && !service->overridable) {
 331                logerror("'%s': service not enabled.", service->name);
 332                errno = EACCES;
 333                return daemon_error(dir, "service not enabled");
 334        }
 335
 336        if (!(path = path_ok(dir)))
 337                return daemon_error(dir, "no such repository");
 338
 339        /*
 340         * Security on the cheap.
 341         *
 342         * We want a readable HEAD, usable "objects" directory, and
 343         * a "git-daemon-export-ok" flag that says that the other side
 344         * is ok with us doing this.
 345         *
 346         * path_ok() uses enter_repo() and does whitelist checking.
 347         * We only need to make sure the repository is exported.
 348         */
 349
 350        if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 351                logerror("'%s': repository not exported.", path);
 352                errno = EACCES;
 353                return daemon_error(dir, "repository not exported");
 354        }
 355
 356        if (service->overridable) {
 357                service_looking_at = service;
 358                service_enabled = -1;
 359                git_config(git_daemon_config, NULL);
 360                if (0 <= service_enabled)
 361                        enabled = service_enabled;
 362        }
 363        if (!enabled) {
 364                logerror("'%s': service not enabled for '%s'",
 365                         service->name, path);
 366                errno = EACCES;
 367                return daemon_error(dir, "service not enabled");
 368        }
 369
 370        /*
 371         * Optionally, a hook can choose to deny access to the
 372         * repository depending on the phase of the moon.
 373         */
 374        if (access_hook && run_access_hook(service, dir, path))
 375                return -1;
 376
 377        /*
 378         * We'll ignore SIGTERM from now on, we have a
 379         * good client.
 380         */
 381        signal(SIGTERM, SIG_IGN);
 382
 383        return service->fn();
 384}
 385
 386static void copy_to_log(int fd)
 387{
 388        struct strbuf line = STRBUF_INIT;
 389        FILE *fp;
 390
 391        fp = fdopen(fd, "r");
 392        if (fp == NULL) {
 393                logerror("fdopen of error channel failed");
 394                close(fd);
 395                return;
 396        }
 397
 398        while (strbuf_getline(&line, fp, '\n') != EOF) {
 399                logerror("%s", line.buf);
 400                strbuf_setlen(&line, 0);
 401        }
 402
 403        strbuf_release(&line);
 404        fclose(fp);
 405}
 406
 407static int run_service_command(const char **argv)
 408{
 409        struct child_process cld;
 410
 411        memset(&cld, 0, sizeof(cld));
 412        cld.argv = argv;
 413        cld.git_cmd = 1;
 414        cld.err = -1;
 415        if (start_command(&cld))
 416                return -1;
 417
 418        close(0);
 419        close(1);
 420
 421        copy_to_log(cld.err);
 422
 423        return finish_command(&cld);
 424}
 425
 426static int upload_pack(void)
 427{
 428        /* Timeout as string */
 429        char timeout_buf[64];
 430        const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
 431
 432        argv[2] = timeout_buf;
 433
 434        snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 435        return run_service_command(argv);
 436}
 437
 438static int upload_archive(void)
 439{
 440        static const char *argv[] = { "upload-archive", ".", NULL };
 441        return run_service_command(argv);
 442}
 443
 444static int receive_pack(void)
 445{
 446        static const char *argv[] = { "receive-pack", ".", NULL };
 447        return run_service_command(argv);
 448}
 449
 450static struct daemon_service daemon_service[] = {
 451        { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 452        { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 453        { "receive-pack", "receivepack", receive_pack, 0, 1 },
 454};
 455
 456static void enable_service(const char *name, int ena)
 457{
 458        int i;
 459        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 460                if (!strcmp(daemon_service[i].name, name)) {
 461                        daemon_service[i].enabled = ena;
 462                        return;
 463                }
 464        }
 465        die("No such service %s", name);
 466}
 467
 468static void make_service_overridable(const char *name, int ena)
 469{
 470        int i;
 471        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 472                if (!strcmp(daemon_service[i].name, name)) {
 473                        daemon_service[i].overridable = ena;
 474                        return;
 475                }
 476        }
 477        die("No such service %s", name);
 478}
 479
 480static void parse_host_and_port(char *hostport, char **host,
 481        char **port)
 482{
 483        if (*hostport == '[') {
 484                char *end;
 485
 486                end = strchr(hostport, ']');
 487                if (!end)
 488                        die("Invalid request ('[' without ']')");
 489                *end = '\0';
 490                *host = hostport + 1;
 491                if (!end[1])
 492                        *port = NULL;
 493                else if (end[1] == ':')
 494                        *port = end + 2;
 495                else
 496                        die("Garbage after end of host part");
 497        } else {
 498                *host = hostport;
 499                *port = strrchr(hostport, ':');
 500                if (*port) {
 501                        **port = '\0';
 502                        ++*port;
 503                }
 504        }
 505}
 506
 507/*
 508 * Read the host as supplied by the client connection.
 509 */
 510static void parse_host_arg(char *extra_args, int buflen)
 511{
 512        char *val;
 513        int vallen;
 514        char *end = extra_args + buflen;
 515
 516        if (extra_args < end && *extra_args) {
 517                saw_extended_args = 1;
 518                if (strncasecmp("host=", extra_args, 5) == 0) {
 519                        val = extra_args + 5;
 520                        vallen = strlen(val) + 1;
 521                        if (*val) {
 522                                /* Split <host>:<port> at colon. */
 523                                char *host;
 524                                char *port;
 525                                parse_host_and_port(val, &host, &port);
 526                                if (port) {
 527                                        free(tcp_port);
 528                                        tcp_port = xstrdup(port);
 529                                }
 530                                free(hostname);
 531                                hostname = xstrdup_tolower(host);
 532                        }
 533
 534                        /* On to the next one */
 535                        extra_args = val + vallen;
 536                }
 537                if (extra_args < end && *extra_args)
 538                        die("Invalid request");
 539        }
 540
 541        /*
 542         * Locate canonical hostname and its IP address.
 543         */
 544        if (hostname) {
 545#ifndef NO_IPV6
 546                struct addrinfo hints;
 547                struct addrinfo *ai;
 548                int gai;
 549                static char addrbuf[HOST_NAME_MAX + 1];
 550
 551                memset(&hints, 0, sizeof(hints));
 552                hints.ai_flags = AI_CANONNAME;
 553
 554                gai = getaddrinfo(hostname, NULL, &hints, &ai);
 555                if (!gai) {
 556                        struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 557
 558                        inet_ntop(AF_INET, &sin_addr->sin_addr,
 559                                  addrbuf, sizeof(addrbuf));
 560                        free(ip_address);
 561                        ip_address = xstrdup(addrbuf);
 562
 563                        free(canon_hostname);
 564                        canon_hostname = xstrdup(ai->ai_canonname ?
 565                                                 ai->ai_canonname : ip_address);
 566
 567                        freeaddrinfo(ai);
 568                }
 569#else
 570                struct hostent *hent;
 571                struct sockaddr_in sa;
 572                char **ap;
 573                static char addrbuf[HOST_NAME_MAX + 1];
 574
 575                hent = gethostbyname(hostname);
 576
 577                ap = hent->h_addr_list;
 578                memset(&sa, 0, sizeof sa);
 579                sa.sin_family = hent->h_addrtype;
 580                sa.sin_port = htons(0);
 581                memcpy(&sa.sin_addr, *ap, hent->h_length);
 582
 583                inet_ntop(hent->h_addrtype, &sa.sin_addr,
 584                          addrbuf, sizeof(addrbuf));
 585
 586                free(canon_hostname);
 587                canon_hostname = xstrdup(hent->h_name);
 588                free(ip_address);
 589                ip_address = xstrdup(addrbuf);
 590#endif
 591        }
 592}
 593
 594
 595static int execute(void)
 596{
 597        char *line = packet_buffer;
 598        int pktlen, len, i;
 599        char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
 600
 601        if (addr)
 602                loginfo("Connection from %s:%s", addr, port);
 603
 604        alarm(init_timeout ? init_timeout : timeout);
 605        pktlen = packet_read(0, NULL, NULL, packet_buffer, sizeof(packet_buffer), 0);
 606        alarm(0);
 607
 608        len = strlen(line);
 609        if (pktlen != len)
 610                loginfo("Extended attributes (%d bytes) exist <%.*s>",
 611                        (int) pktlen - len,
 612                        (int) pktlen - len, line + len + 1);
 613        if (len && line[len-1] == '\n') {
 614                line[--len] = 0;
 615                pktlen--;
 616        }
 617
 618        free(hostname);
 619        free(canon_hostname);
 620        free(ip_address);
 621        free(tcp_port);
 622        hostname = canon_hostname = ip_address = tcp_port = NULL;
 623
 624        if (len != pktlen)
 625                parse_host_arg(line + len + 1, pktlen - len - 1);
 626
 627        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 628                struct daemon_service *s = &(daemon_service[i]);
 629                const char *arg;
 630
 631                if (skip_prefix(line, "git-", &arg) &&
 632                    skip_prefix(arg, s->name, &arg) &&
 633                    *arg++ == ' ') {
 634                        /*
 635                         * Note: The directory here is probably context sensitive,
 636                         * and might depend on the actual service being performed.
 637                         */
 638                        return run_service(arg, s);
 639                }
 640        }
 641
 642        logerror("Protocol error: '%s'", line);
 643        return -1;
 644}
 645
 646static int addrcmp(const struct sockaddr_storage *s1,
 647    const struct sockaddr_storage *s2)
 648{
 649        const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 650        const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 651
 652        if (sa1->sa_family != sa2->sa_family)
 653                return sa1->sa_family - sa2->sa_family;
 654        if (sa1->sa_family == AF_INET)
 655                return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 656                    &((struct sockaddr_in *)s2)->sin_addr,
 657                    sizeof(struct in_addr));
 658#ifndef NO_IPV6
 659        if (sa1->sa_family == AF_INET6)
 660                return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 661                    &((struct sockaddr_in6 *)s2)->sin6_addr,
 662                    sizeof(struct in6_addr));
 663#endif
 664        return 0;
 665}
 666
 667static int max_connections = 32;
 668
 669static unsigned int live_children;
 670
 671static struct child {
 672        struct child *next;
 673        struct child_process cld;
 674        struct sockaddr_storage address;
 675} *firstborn;
 676
 677static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
 678{
 679        struct child *newborn, **cradle;
 680
 681        newborn = xcalloc(1, sizeof(*newborn));
 682        live_children++;
 683        memcpy(&newborn->cld, cld, sizeof(*cld));
 684        memcpy(&newborn->address, addr, addrlen);
 685        for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 686                if (!addrcmp(&(*cradle)->address, &newborn->address))
 687                        break;
 688        newborn->next = *cradle;
 689        *cradle = newborn;
 690}
 691
 692/*
 693 * This gets called if the number of connections grows
 694 * past "max_connections".
 695 *
 696 * We kill the newest connection from a duplicate IP.
 697 */
 698static void kill_some_child(void)
 699{
 700        const struct child *blanket, *next;
 701
 702        if (!(blanket = firstborn))
 703                return;
 704
 705        for (; (next = blanket->next); blanket = next)
 706                if (!addrcmp(&blanket->address, &next->address)) {
 707                        kill(blanket->cld.pid, SIGTERM);
 708                        break;
 709                }
 710}
 711
 712static void check_dead_children(void)
 713{
 714        int status;
 715        pid_t pid;
 716
 717        struct child **cradle, *blanket;
 718        for (cradle = &firstborn; (blanket = *cradle);)
 719                if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
 720                        const char *dead = "";
 721                        if (status)
 722                                dead = " (with error)";
 723                        loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 724
 725                        /* remove the child */
 726                        *cradle = blanket->next;
 727                        live_children--;
 728                        free(blanket);
 729                } else
 730                        cradle = &blanket->next;
 731}
 732
 733static char **cld_argv;
 734static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 735{
 736        struct child_process cld = { NULL };
 737        char addrbuf[300] = "REMOTE_ADDR=", portbuf[300];
 738        char *env[] = { addrbuf, portbuf, NULL };
 739
 740        if (max_connections && live_children >= max_connections) {
 741                kill_some_child();
 742                sleep(1);  /* give it some time to die */
 743                check_dead_children();
 744                if (live_children >= max_connections) {
 745                        close(incoming);
 746                        logerror("Too many children, dropping connection");
 747                        return;
 748                }
 749        }
 750
 751        if (addr->sa_family == AF_INET) {
 752                struct sockaddr_in *sin_addr = (void *) addr;
 753                inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf + 12,
 754                    sizeof(addrbuf) - 12);
 755                snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 756                    ntohs(sin_addr->sin_port));
 757#ifndef NO_IPV6
 758        } else if (addr->sa_family == AF_INET6) {
 759                struct sockaddr_in6 *sin6_addr = (void *) addr;
 760
 761                char *buf = addrbuf + 12;
 762                *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 763                inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf,
 764                    sizeof(addrbuf) - 13);
 765                strcat(buf, "]");
 766
 767                snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 768                    ntohs(sin6_addr->sin6_port));
 769#endif
 770        }
 771
 772        cld.env = (const char **)env;
 773        cld.argv = (const char **)cld_argv;
 774        cld.in = incoming;
 775        cld.out = dup(incoming);
 776
 777        if (start_command(&cld))
 778                logerror("unable to fork");
 779        else
 780                add_child(&cld, addr, addrlen);
 781}
 782
 783static void child_handler(int signo)
 784{
 785        /*
 786         * Otherwise empty handler because systemcalls will get interrupted
 787         * upon signal receipt
 788         * SysV needs the handler to be rearmed
 789         */
 790        signal(SIGCHLD, child_handler);
 791}
 792
 793static int set_reuse_addr(int sockfd)
 794{
 795        int on = 1;
 796
 797        if (!reuseaddr)
 798                return 0;
 799        return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 800                          &on, sizeof(on));
 801}
 802
 803struct socketlist {
 804        int *list;
 805        size_t nr;
 806        size_t alloc;
 807};
 808
 809static const char *ip2str(int family, struct sockaddr *sin, socklen_t len)
 810{
 811#ifdef NO_IPV6
 812        static char ip[INET_ADDRSTRLEN];
 813#else
 814        static char ip[INET6_ADDRSTRLEN];
 815#endif
 816
 817        switch (family) {
 818#ifndef NO_IPV6
 819        case AF_INET6:
 820                inet_ntop(family, &((struct sockaddr_in6*)sin)->sin6_addr, ip, len);
 821                break;
 822#endif
 823        case AF_INET:
 824                inet_ntop(family, &((struct sockaddr_in*)sin)->sin_addr, ip, len);
 825                break;
 826        default:
 827                strcpy(ip, "<unknown>");
 828        }
 829        return ip;
 830}
 831
 832#ifndef NO_IPV6
 833
 834static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 835{
 836        int socknum = 0;
 837        int maxfd = -1;
 838        char pbuf[NI_MAXSERV];
 839        struct addrinfo hints, *ai0, *ai;
 840        int gai;
 841        long flags;
 842
 843        sprintf(pbuf, "%d", listen_port);
 844        memset(&hints, 0, sizeof(hints));
 845        hints.ai_family = AF_UNSPEC;
 846        hints.ai_socktype = SOCK_STREAM;
 847        hints.ai_protocol = IPPROTO_TCP;
 848        hints.ai_flags = AI_PASSIVE;
 849
 850        gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 851        if (gai) {
 852                logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
 853                return 0;
 854        }
 855
 856        for (ai = ai0; ai; ai = ai->ai_next) {
 857                int sockfd;
 858
 859                sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 860                if (sockfd < 0)
 861                        continue;
 862                if (sockfd >= FD_SETSIZE) {
 863                        logerror("Socket descriptor too large");
 864                        close(sockfd);
 865                        continue;
 866                }
 867
 868#ifdef IPV6_V6ONLY
 869                if (ai->ai_family == AF_INET6) {
 870                        int on = 1;
 871                        setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 872                                   &on, sizeof(on));
 873                        /* Note: error is not fatal */
 874                }
 875#endif
 876
 877                if (set_reuse_addr(sockfd)) {
 878                        logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 879                        close(sockfd);
 880                        continue;
 881                }
 882
 883                if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 884                        logerror("Could not bind to %s: %s",
 885                                 ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 886                                 strerror(errno));
 887                        close(sockfd);
 888                        continue;       /* not fatal */
 889                }
 890                if (listen(sockfd, 5) < 0) {
 891                        logerror("Could not listen to %s: %s",
 892                                 ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 893                                 strerror(errno));
 894                        close(sockfd);
 895                        continue;       /* not fatal */
 896                }
 897
 898                flags = fcntl(sockfd, F_GETFD, 0);
 899                if (flags >= 0)
 900                        fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 901
 902                ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 903                socklist->list[socklist->nr++] = sockfd;
 904                socknum++;
 905
 906                if (maxfd < sockfd)
 907                        maxfd = sockfd;
 908        }
 909
 910        freeaddrinfo(ai0);
 911
 912        return socknum;
 913}
 914
 915#else /* NO_IPV6 */
 916
 917static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 918{
 919        struct sockaddr_in sin;
 920        int sockfd;
 921        long flags;
 922
 923        memset(&sin, 0, sizeof sin);
 924        sin.sin_family = AF_INET;
 925        sin.sin_port = htons(listen_port);
 926
 927        if (listen_addr) {
 928                /* Well, host better be an IP address here. */
 929                if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 930                        return 0;
 931        } else {
 932                sin.sin_addr.s_addr = htonl(INADDR_ANY);
 933        }
 934
 935        sockfd = socket(AF_INET, SOCK_STREAM, 0);
 936        if (sockfd < 0)
 937                return 0;
 938
 939        if (set_reuse_addr(sockfd)) {
 940                logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 941                close(sockfd);
 942                return 0;
 943        }
 944
 945        if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 946                logerror("Could not listen to %s: %s",
 947                         ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
 948                         strerror(errno));
 949                close(sockfd);
 950                return 0;
 951        }
 952
 953        if (listen(sockfd, 5) < 0) {
 954                logerror("Could not listen to %s: %s",
 955                         ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
 956                         strerror(errno));
 957                close(sockfd);
 958                return 0;
 959        }
 960
 961        flags = fcntl(sockfd, F_GETFD, 0);
 962        if (flags >= 0)
 963                fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 964
 965        ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 966        socklist->list[socklist->nr++] = sockfd;
 967        return 1;
 968}
 969
 970#endif
 971
 972static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
 973{
 974        if (!listen_addr->nr)
 975                setup_named_sock(NULL, listen_port, socklist);
 976        else {
 977                int i, socknum;
 978                for (i = 0; i < listen_addr->nr; i++) {
 979                        socknum = setup_named_sock(listen_addr->items[i].string,
 980                                                   listen_port, socklist);
 981
 982                        if (socknum == 0)
 983                                logerror("unable to allocate any listen sockets for host %s on port %u",
 984                                         listen_addr->items[i].string, listen_port);
 985                }
 986        }
 987}
 988
 989static int service_loop(struct socketlist *socklist)
 990{
 991        struct pollfd *pfd;
 992        int i;
 993
 994        pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
 995
 996        for (i = 0; i < socklist->nr; i++) {
 997                pfd[i].fd = socklist->list[i];
 998                pfd[i].events = POLLIN;
 999        }
1000
1001        signal(SIGCHLD, child_handler);
1002
1003        for (;;) {
1004                int i;
1005
1006                check_dead_children();
1007
1008                if (poll(pfd, socklist->nr, -1) < 0) {
1009                        if (errno != EINTR) {
1010                                logerror("Poll failed, resuming: %s",
1011                                      strerror(errno));
1012                                sleep(1);
1013                        }
1014                        continue;
1015                }
1016
1017                for (i = 0; i < socklist->nr; i++) {
1018                        if (pfd[i].revents & POLLIN) {
1019                                union {
1020                                        struct sockaddr sa;
1021                                        struct sockaddr_in sai;
1022#ifndef NO_IPV6
1023                                        struct sockaddr_in6 sai6;
1024#endif
1025                                } ss;
1026                                socklen_t sslen = sizeof(ss);
1027                                int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
1028                                if (incoming < 0) {
1029                                        switch (errno) {
1030                                        case EAGAIN:
1031                                        case EINTR:
1032                                        case ECONNABORTED:
1033                                                continue;
1034                                        default:
1035                                                die_errno("accept returned");
1036                                        }
1037                                }
1038                                handle(incoming, &ss.sa, sslen);
1039                        }
1040                }
1041        }
1042}
1043
1044#ifdef NO_POSIX_GOODIES
1045
1046struct credentials;
1047
1048static void drop_privileges(struct credentials *cred)
1049{
1050        /* nothing */
1051}
1052
1053static struct credentials *prepare_credentials(const char *user_name,
1054    const char *group_name)
1055{
1056        die("--user not supported on this platform");
1057}
1058
1059#else
1060
1061struct credentials {
1062        struct passwd *pass;
1063        gid_t gid;
1064};
1065
1066static void drop_privileges(struct credentials *cred)
1067{
1068        if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
1069            setgid (cred->gid) || setuid(cred->pass->pw_uid)))
1070                die("cannot drop privileges");
1071}
1072
1073static struct credentials *prepare_credentials(const char *user_name,
1074    const char *group_name)
1075{
1076        static struct credentials c;
1077
1078        c.pass = getpwnam(user_name);
1079        if (!c.pass)
1080                die("user not found - %s", user_name);
1081
1082        if (!group_name)
1083                c.gid = c.pass->pw_gid;
1084        else {
1085                struct group *group = getgrnam(group_name);
1086                if (!group)
1087                        die("group not found - %s", group_name);
1088
1089                c.gid = group->gr_gid;
1090        }
1091
1092        return &c;
1093}
1094#endif
1095
1096static void store_pid(const char *path)
1097{
1098        FILE *f = fopen(path, "w");
1099        if (!f)
1100                die_errno("cannot open pid file '%s'", path);
1101        if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
1102                die_errno("failed to write pid file '%s'", path);
1103}
1104
1105static int serve(struct string_list *listen_addr, int listen_port,
1106    struct credentials *cred)
1107{
1108        struct socketlist socklist = { NULL, 0, 0 };
1109
1110        socksetup(listen_addr, listen_port, &socklist);
1111        if (socklist.nr == 0)
1112                die("unable to allocate any listen sockets on port %u",
1113                    listen_port);
1114
1115        drop_privileges(cred);
1116
1117        loginfo("Ready to rumble");
1118
1119        return service_loop(&socklist);
1120}
1121
1122int main(int argc, char **argv)
1123{
1124        int listen_port = 0;
1125        struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1126        int serve_mode = 0, inetd_mode = 0;
1127        const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1128        int detach = 0;
1129        struct credentials *cred = NULL;
1130        int i;
1131
1132        git_setup_gettext();
1133
1134        git_extract_argv0_path(argv[0]);
1135
1136        for (i = 1; i < argc; i++) {
1137                char *arg = argv[i];
1138                const char *v;
1139
1140                if (skip_prefix(arg, "--listen=", &v)) {
1141                        string_list_append(&listen_addr, xstrdup_tolower(v));
1142                        continue;
1143                }
1144                if (skip_prefix(arg, "--port=", &v)) {
1145                        char *end;
1146                        unsigned long n;
1147                        n = strtoul(v, &end, 0);
1148                        if (*v && !*end) {
1149                                listen_port = n;
1150                                continue;
1151                        }
1152                }
1153                if (!strcmp(arg, "--serve")) {
1154                        serve_mode = 1;
1155                        continue;
1156                }
1157                if (!strcmp(arg, "--inetd")) {
1158                        inetd_mode = 1;
1159                        log_syslog = 1;
1160                        continue;
1161                }
1162                if (!strcmp(arg, "--verbose")) {
1163                        verbose = 1;
1164                        continue;
1165                }
1166                if (!strcmp(arg, "--syslog")) {
1167                        log_syslog = 1;
1168                        continue;
1169                }
1170                if (!strcmp(arg, "--export-all")) {
1171                        export_all_trees = 1;
1172                        continue;
1173                }
1174                if (skip_prefix(arg, "--access-hook=", &v)) {
1175                        access_hook = v;
1176                        continue;
1177                }
1178                if (skip_prefix(arg, "--timeout=", &v)) {
1179                        timeout = atoi(v);
1180                        continue;
1181                }
1182                if (skip_prefix(arg, "--init-timeout=", &v)) {
1183                        init_timeout = atoi(v);
1184                        continue;
1185                }
1186                if (skip_prefix(arg, "--max-connections=", &v)) {
1187                        max_connections = atoi(v);
1188                        if (max_connections < 0)
1189                                max_connections = 0;            /* unlimited */
1190                        continue;
1191                }
1192                if (!strcmp(arg, "--strict-paths")) {
1193                        strict_paths = 1;
1194                        continue;
1195                }
1196                if (skip_prefix(arg, "--base-path=", &v)) {
1197                        base_path = v;
1198                        continue;
1199                }
1200                if (!strcmp(arg, "--base-path-relaxed")) {
1201                        base_path_relaxed = 1;
1202                        continue;
1203                }
1204                if (skip_prefix(arg, "--interpolated-path=", &v)) {
1205                        interpolated_path = v;
1206                        continue;
1207                }
1208                if (!strcmp(arg, "--reuseaddr")) {
1209                        reuseaddr = 1;
1210                        continue;
1211                }
1212                if (!strcmp(arg, "--user-path")) {
1213                        user_path = "";
1214                        continue;
1215                }
1216                if (skip_prefix(arg, "--user-path=", &v)) {
1217                        user_path = v;
1218                        continue;
1219                }
1220                if (skip_prefix(arg, "--pid-file=", &v)) {
1221                        pid_file = v;
1222                        continue;
1223                }
1224                if (!strcmp(arg, "--detach")) {
1225                        detach = 1;
1226                        log_syslog = 1;
1227                        continue;
1228                }
1229                if (skip_prefix(arg, "--user=", &v)) {
1230                        user_name = v;
1231                        continue;
1232                }
1233                if (skip_prefix(arg, "--group=", &v)) {
1234                        group_name = v;
1235                        continue;
1236                }
1237                if (skip_prefix(arg, "--enable=", &v)) {
1238                        enable_service(v, 1);
1239                        continue;
1240                }
1241                if (skip_prefix(arg, "--disable=", &v)) {
1242                        enable_service(v, 0);
1243                        continue;
1244                }
1245                if (skip_prefix(arg, "--allow-override=", &v)) {
1246                        make_service_overridable(v, 1);
1247                        continue;
1248                }
1249                if (skip_prefix(arg, "--forbid-override=", &v)) {
1250                        make_service_overridable(v, 0);
1251                        continue;
1252                }
1253                if (!strcmp(arg, "--informative-errors")) {
1254                        informative_errors = 1;
1255                        continue;
1256                }
1257                if (!strcmp(arg, "--no-informative-errors")) {
1258                        informative_errors = 0;
1259                        continue;
1260                }
1261                if (!strcmp(arg, "--")) {
1262                        ok_paths = &argv[i+1];
1263                        break;
1264                } else if (arg[0] != '-') {
1265                        ok_paths = &argv[i];
1266                        break;
1267                }
1268
1269                usage(daemon_usage);
1270        }
1271
1272        if (log_syslog) {
1273                openlog("git-daemon", LOG_PID, LOG_DAEMON);
1274                set_die_routine(daemon_die);
1275        } else
1276                /* avoid splitting a message in the middle */
1277                setvbuf(stderr, NULL, _IOFBF, 4096);
1278
1279        if (inetd_mode && (detach || group_name || user_name))
1280                die("--detach, --user and --group are incompatible with --inetd");
1281
1282        if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1283                die("--listen= and --port= are incompatible with --inetd");
1284        else if (listen_port == 0)
1285                listen_port = DEFAULT_GIT_PORT;
1286
1287        if (group_name && !user_name)
1288                die("--group supplied without --user");
1289
1290        if (user_name)
1291                cred = prepare_credentials(user_name, group_name);
1292
1293        if (strict_paths && (!ok_paths || !*ok_paths))
1294                die("option --strict-paths requires a whitelist");
1295
1296        if (base_path && !is_directory(base_path))
1297                die("base-path '%s' does not exist or is not a directory",
1298                    base_path);
1299
1300        if (inetd_mode) {
1301                if (!freopen("/dev/null", "w", stderr))
1302                        die_errno("failed to redirect stderr to /dev/null");
1303        }
1304
1305        if (inetd_mode || serve_mode)
1306                return execute();
1307
1308        if (detach) {
1309                if (daemonize())
1310                        die("--detach not supported on this platform");
1311        } else
1312                sanitize_stdfds();
1313
1314        if (pid_file)
1315                store_pid(pid_file);
1316
1317        /* prepare argv for serving-processes */
1318        cld_argv = xmalloc(sizeof (char *) * (argc + 2));
1319        cld_argv[0] = argv[0];  /* git-daemon */
1320        cld_argv[1] = "--serve";
1321        for (i = 1; i < argc; ++i)
1322                cld_argv[i+1] = argv[i];
1323        cld_argv[argc+1] = NULL;
1324
1325        return serve(&listen_addr, listen_port, cred);
1326}