Andrew's git / gitweb.git / daemon.c
?
daemon.con commit Merge branch 'jk/parse-options-concat' into maint (60b84ba)
   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/* If defined, ~user notation is allowed and the string is inserted
  47 * after ~user/.  E.g. a request to git://host/~alice/frotz would
  48 * go to /home/alice/pub_git/frotz with --user-path=pub_git.
  49 */
  50static const char *user_path;
  51
  52/* Timeout, and initial timeout */
  53static unsigned int timeout;
  54static unsigned int init_timeout;
  55
  56struct hostinfo {
  57        struct strbuf hostname;
  58        struct strbuf canon_hostname;
  59        struct strbuf ip_address;
  60        struct strbuf tcp_port;
  61        unsigned int hostname_lookup_done:1;
  62        unsigned int saw_extended_args:1;
  63};
  64
  65static void lookup_hostname(struct hostinfo *hi);
  66
  67static const char *get_canon_hostname(struct hostinfo *hi)
  68{
  69        lookup_hostname(hi);
  70        return hi->canon_hostname.buf;
  71}
  72
  73static const char *get_ip_address(struct hostinfo *hi)
  74{
  75        lookup_hostname(hi);
  76        return hi->ip_address.buf;
  77}
  78
  79static void logreport(int priority, const char *err, va_list params)
  80{
  81        if (log_syslog) {
  82                char buf[1024];
  83                vsnprintf(buf, sizeof(buf), err, params);
  84                syslog(priority, "%s", buf);
  85        } else {
  86                /*
  87                 * Since stderr is set to buffered mode, the
  88                 * logging of different processes will not overlap
  89                 * unless they overflow the (rather big) buffers.
  90                 */
  91                fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
  92                vfprintf(stderr, err, params);
  93                fputc('\n', stderr);
  94                fflush(stderr);
  95        }
  96}
  97
  98__attribute__((format (printf, 1, 2)))
  99static void logerror(const char *err, ...)
 100{
 101        va_list params;
 102        va_start(params, err);
 103        logreport(LOG_ERR, err, params);
 104        va_end(params);
 105}
 106
 107__attribute__((format (printf, 1, 2)))
 108static void loginfo(const char *err, ...)
 109{
 110        va_list params;
 111        if (!verbose)
 112                return;
 113        va_start(params, err);
 114        logreport(LOG_INFO, err, params);
 115        va_end(params);
 116}
 117
 118static void NORETURN daemon_die(const char *err, va_list params)
 119{
 120        logreport(LOG_ERR, err, params);
 121        exit(1);
 122}
 123
 124struct expand_path_context {
 125        const char *directory;
 126        struct hostinfo *hostinfo;
 127};
 128
 129static size_t expand_path(struct strbuf *sb, const char *placeholder, void *ctx)
 130{
 131        struct expand_path_context *context = ctx;
 132        struct hostinfo *hi = context->hostinfo;
 133
 134        switch (placeholder[0]) {
 135        case 'H':
 136                strbuf_addbuf(sb, &hi->hostname);
 137                return 1;
 138        case 'C':
 139                if (placeholder[1] == 'H') {
 140                        strbuf_addstr(sb, get_canon_hostname(hi));
 141                        return 2;
 142                }
 143                break;
 144        case 'I':
 145                if (placeholder[1] == 'P') {
 146                        strbuf_addstr(sb, get_ip_address(hi));
 147                        return 2;
 148                }
 149                break;
 150        case 'P':
 151                strbuf_addbuf(sb, &hi->tcp_port);
 152                return 1;
 153        case 'D':
 154                strbuf_addstr(sb, context->directory);
 155                return 1;
 156        }
 157        return 0;
 158}
 159
 160static const char *path_ok(const char *directory, struct hostinfo *hi)
 161{
 162        static char rpath[PATH_MAX];
 163        static char interp_path[PATH_MAX];
 164        const char *path;
 165        const char *dir;
 166
 167        dir = directory;
 168
 169        if (daemon_avoid_alias(dir)) {
 170                logerror("'%s': aliased", dir);
 171                return NULL;
 172        }
 173
 174        if (*dir == '~') {
 175                if (!user_path) {
 176                        logerror("'%s': User-path not allowed", dir);
 177                        return NULL;
 178                }
 179                if (*user_path) {
 180                        /* Got either "~alice" or "~alice/foo";
 181                         * rewrite them to "~alice/%s" or
 182                         * "~alice/%s/foo".
 183                         */
 184                        int namlen, restlen = strlen(dir);
 185                        const char *slash = strchr(dir, '/');
 186                        if (!slash)
 187                                slash = dir + restlen;
 188                        namlen = slash - dir;
 189                        restlen -= namlen;
 190                        loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
 191                        snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
 192                                 namlen, dir, user_path, restlen, slash);
 193                        dir = rpath;
 194                }
 195        }
 196        else if (interpolated_path && hi->saw_extended_args) {
 197                struct strbuf expanded_path = STRBUF_INIT;
 198                struct expand_path_context context;
 199
 200                context.directory = directory;
 201                context.hostinfo = hi;
 202
 203                if (*dir != '/') {
 204                        /* Allow only absolute */
 205                        logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 206                        return NULL;
 207                }
 208
 209                strbuf_expand(&expanded_path, interpolated_path,
 210                              expand_path, &context);
 211                strlcpy(interp_path, expanded_path.buf, PATH_MAX);
 212                strbuf_release(&expanded_path);
 213                loginfo("Interpolated dir '%s'", interp_path);
 214
 215                dir = interp_path;
 216        }
 217        else if (base_path) {
 218                if (*dir != '/') {
 219                        /* Allow only absolute */
 220                        logerror("'%s': Non-absolute path denied (base-path active)", dir);
 221                        return NULL;
 222                }
 223                snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
 224                dir = rpath;
 225        }
 226
 227        path = enter_repo(dir, strict_paths);
 228        if (!path && base_path && base_path_relaxed) {
 229                /*
 230                 * if we fail and base_path_relaxed is enabled, try without
 231                 * prefixing the base path
 232                 */
 233                dir = directory;
 234                path = enter_repo(dir, strict_paths);
 235        }
 236
 237        if (!path) {
 238                logerror("'%s' does not appear to be a git repository", dir);
 239                return NULL;
 240        }
 241
 242        if ( ok_paths && *ok_paths ) {
 243                char **pp;
 244                int pathlen = strlen(path);
 245
 246                /* The validation is done on the paths after enter_repo
 247                 * appends optional {.git,.git/.git} and friends, but
 248                 * it does not use getcwd().  So if your /pub is
 249                 * a symlink to /mnt/pub, you can whitelist /pub and
 250                 * do not have to say /mnt/pub.
 251                 * Do not say /pub/.
 252                 */
 253                for ( pp = ok_paths ; *pp ; pp++ ) {
 254                        int len = strlen(*pp);
 255                        if (len <= pathlen &&
 256                            !memcmp(*pp, path, len) &&
 257                            (path[len] == '\0' ||
 258                             (!strict_paths && path[len] == '/')))
 259                                return path;
 260                }
 261        }
 262        else {
 263                /* be backwards compatible */
 264                if (!strict_paths)
 265                        return path;
 266        }
 267
 268        logerror("'%s': not in whitelist", path);
 269        return NULL;            /* Fallthrough. Deny by default */
 270}
 271
 272typedef int (*daemon_service_fn)(void);
 273struct daemon_service {
 274        const char *name;
 275        const char *config_name;
 276        daemon_service_fn fn;
 277        int enabled;
 278        int overridable;
 279};
 280
 281static int daemon_error(const char *dir, const char *msg)
 282{
 283        if (!informative_errors)
 284                msg = "access denied or repository not exported";
 285        packet_write(1, "ERR %s: %s", msg, dir);
 286        return -1;
 287}
 288
 289static const char *access_hook;
 290
 291static int run_access_hook(struct daemon_service *service, const char *dir,
 292                           const char *path, struct hostinfo *hi)
 293{
 294        struct child_process child = CHILD_PROCESS_INIT;
 295        struct strbuf buf = STRBUF_INIT;
 296        const char *argv[8];
 297        const char **arg = argv;
 298        char *eol;
 299        int seen_errors = 0;
 300
 301        *arg++ = access_hook;
 302        *arg++ = service->name;
 303        *arg++ = path;
 304        *arg++ = hi->hostname.buf;
 305        *arg++ = get_canon_hostname(hi);
 306        *arg++ = get_ip_address(hi);
 307        *arg++ = hi->tcp_port.buf;
 308        *arg = NULL;
 309
 310        child.use_shell = 1;
 311        child.argv = argv;
 312        child.no_stdin = 1;
 313        child.no_stderr = 1;
 314        child.out = -1;
 315        if (start_command(&child)) {
 316                logerror("daemon access hook '%s' failed to start",
 317                         access_hook);
 318                goto error_return;
 319        }
 320        if (strbuf_read(&buf, child.out, 0) < 0) {
 321                logerror("failed to read from pipe to daemon access hook '%s'",
 322                         access_hook);
 323                strbuf_reset(&buf);
 324                seen_errors = 1;
 325        }
 326        if (close(child.out) < 0) {
 327                logerror("failed to close pipe to daemon access hook '%s'",
 328                         access_hook);
 329                seen_errors = 1;
 330        }
 331        if (finish_command(&child))
 332                seen_errors = 1;
 333
 334        if (!seen_errors) {
 335                strbuf_release(&buf);
 336                return 0;
 337        }
 338
 339error_return:
 340        strbuf_ltrim(&buf);
 341        if (!buf.len)
 342                strbuf_addstr(&buf, "service rejected");
 343        eol = strchr(buf.buf, '\n');
 344        if (eol)
 345                *eol = '\0';
 346        errno = EACCES;
 347        daemon_error(dir, buf.buf);
 348        strbuf_release(&buf);
 349        return -1;
 350}
 351
 352static int run_service(const char *dir, struct daemon_service *service,
 353                       struct hostinfo *hi)
 354{
 355        const char *path;
 356        int enabled = service->enabled;
 357        struct strbuf var = STRBUF_INIT;
 358
 359        loginfo("Request %s for '%s'", service->name, dir);
 360
 361        if (!enabled && !service->overridable) {
 362                logerror("'%s': service not enabled.", service->name);
 363                errno = EACCES;
 364                return daemon_error(dir, "service not enabled");
 365        }
 366
 367        if (!(path = path_ok(dir, hi)))
 368                return daemon_error(dir, "no such repository");
 369
 370        /*
 371         * Security on the cheap.
 372         *
 373         * We want a readable HEAD, usable "objects" directory, and
 374         * a "git-daemon-export-ok" flag that says that the other side
 375         * is ok with us doing this.
 376         *
 377         * path_ok() uses enter_repo() and does whitelist checking.
 378         * We only need to make sure the repository is exported.
 379         */
 380
 381        if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 382                logerror("'%s': repository not exported.", path);
 383                errno = EACCES;
 384                return daemon_error(dir, "repository not exported");
 385        }
 386
 387        if (service->overridable) {
 388                strbuf_addf(&var, "daemon.%s", service->config_name);
 389                git_config_get_bool(var.buf, &enabled);
 390                strbuf_release(&var);
 391        }
 392        if (!enabled) {
 393                logerror("'%s': service not enabled for '%s'",
 394                         service->name, path);
 395                errno = EACCES;
 396                return daemon_error(dir, "service not enabled");
 397        }
 398
 399        /*
 400         * Optionally, a hook can choose to deny access to the
 401         * repository depending on the phase of the moon.
 402         */
 403        if (access_hook && run_access_hook(service, dir, path, hi))
 404                return -1;
 405
 406        /*
 407         * We'll ignore SIGTERM from now on, we have a
 408         * good client.
 409         */
 410        signal(SIGTERM, SIG_IGN);
 411
 412        return service->fn();
 413}
 414
 415static void copy_to_log(int fd)
 416{
 417        struct strbuf line = STRBUF_INIT;
 418        FILE *fp;
 419
 420        fp = fdopen(fd, "r");
 421        if (fp == NULL) {
 422                logerror("fdopen of error channel failed");
 423                close(fd);
 424                return;
 425        }
 426
 427        while (strbuf_getline_lf(&line, fp) != EOF) {
 428                logerror("%s", line.buf);
 429                strbuf_setlen(&line, 0);
 430        }
 431
 432        strbuf_release(&line);
 433        fclose(fp);
 434}
 435
 436static int run_service_command(const char **argv)
 437{
 438        struct child_process cld = CHILD_PROCESS_INIT;
 439
 440        cld.argv = argv;
 441        cld.git_cmd = 1;
 442        cld.err = -1;
 443        if (start_command(&cld))
 444                return -1;
 445
 446        close(0);
 447        close(1);
 448
 449        copy_to_log(cld.err);
 450
 451        return finish_command(&cld);
 452}
 453
 454static int upload_pack(void)
 455{
 456        /* Timeout as string */
 457        char timeout_buf[64];
 458        const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
 459
 460        argv[2] = timeout_buf;
 461
 462        snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 463        return run_service_command(argv);
 464}
 465
 466static int upload_archive(void)
 467{
 468        static const char *argv[] = { "upload-archive", ".", NULL };
 469        return run_service_command(argv);
 470}
 471
 472static int receive_pack(void)
 473{
 474        static const char *argv[] = { "receive-pack", ".", NULL };
 475        return run_service_command(argv);
 476}
 477
 478static struct daemon_service daemon_service[] = {
 479        { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 480        { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 481        { "receive-pack", "receivepack", receive_pack, 0, 1 },
 482};
 483
 484static void enable_service(const char *name, int ena)
 485{
 486        int i;
 487        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 488                if (!strcmp(daemon_service[i].name, name)) {
 489                        daemon_service[i].enabled = ena;
 490                        return;
 491                }
 492        }
 493        die("No such service %s", name);
 494}
 495
 496static void make_service_overridable(const char *name, int ena)
 497{
 498        int i;
 499        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 500                if (!strcmp(daemon_service[i].name, name)) {
 501                        daemon_service[i].overridable = ena;
 502                        return;
 503                }
 504        }
 505        die("No such service %s", name);
 506}
 507
 508static void parse_host_and_port(char *hostport, char **host,
 509        char **port)
 510{
 511        if (*hostport == '[') {
 512                char *end;
 513
 514                end = strchr(hostport, ']');
 515                if (!end)
 516                        die("Invalid request ('[' without ']')");
 517                *end = '\0';
 518                *host = hostport + 1;
 519                if (!end[1])
 520                        *port = NULL;
 521                else if (end[1] == ':')
 522                        *port = end + 2;
 523                else
 524                        die("Garbage after end of host part");
 525        } else {
 526                *host = hostport;
 527                *port = strrchr(hostport, ':');
 528                if (*port) {
 529                        **port = '\0';
 530                        ++*port;
 531                }
 532        }
 533}
 534
 535/*
 536 * Sanitize a string from the client so that it's OK to be inserted into a
 537 * filesystem path. Specifically, we disallow slashes, runs of "..", and
 538 * trailing and leading dots, which means that the client cannot escape
 539 * our base path via ".." traversal.
 540 */
 541static void sanitize_client(struct strbuf *out, const char *in)
 542{
 543        for (; *in; in++) {
 544                if (*in == '/')
 545                        continue;
 546                if (*in == '.' && (!out->len || out->buf[out->len - 1] == '.'))
 547                        continue;
 548                strbuf_addch(out, *in);
 549        }
 550
 551        while (out->len && out->buf[out->len - 1] == '.')
 552                strbuf_setlen(out, out->len - 1);
 553}
 554
 555/*
 556 * Like sanitize_client, but we also perform any canonicalization
 557 * to make life easier on the admin.
 558 */
 559static void canonicalize_client(struct strbuf *out, const char *in)
 560{
 561        sanitize_client(out, in);
 562        strbuf_tolower(out);
 563}
 564
 565/*
 566 * Read the host as supplied by the client connection.
 567 */
 568static void parse_host_arg(struct hostinfo *hi, char *extra_args, int buflen)
 569{
 570        char *val;
 571        int vallen;
 572        char *end = extra_args + buflen;
 573
 574        if (extra_args < end && *extra_args) {
 575                hi->saw_extended_args = 1;
 576                if (strncasecmp("host=", extra_args, 5) == 0) {
 577                        val = extra_args + 5;
 578                        vallen = strlen(val) + 1;
 579                        if (*val) {
 580                                /* Split <host>:<port> at colon. */
 581                                char *host;
 582                                char *port;
 583                                parse_host_and_port(val, &host, &port);
 584                                if (port)
 585                                        sanitize_client(&hi->tcp_port, port);
 586                                canonicalize_client(&hi->hostname, host);
 587                                hi->hostname_lookup_done = 0;
 588                        }
 589
 590                        /* On to the next one */
 591                        extra_args = val + vallen;
 592                }
 593                if (extra_args < end && *extra_args)
 594                        die("Invalid request");
 595        }
 596}
 597
 598/*
 599 * Locate canonical hostname and its IP address.
 600 */
 601static void lookup_hostname(struct hostinfo *hi)
 602{
 603        if (!hi->hostname_lookup_done && hi->hostname.len) {
 604#ifndef NO_IPV6
 605                struct addrinfo hints;
 606                struct addrinfo *ai;
 607                int gai;
 608                static char addrbuf[HOST_NAME_MAX + 1];
 609
 610                memset(&hints, 0, sizeof(hints));
 611                hints.ai_flags = AI_CANONNAME;
 612
 613                gai = getaddrinfo(hi->hostname.buf, NULL, &hints, &ai);
 614                if (!gai) {
 615                        struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 616
 617                        inet_ntop(AF_INET, &sin_addr->sin_addr,
 618                                  addrbuf, sizeof(addrbuf));
 619                        strbuf_addstr(&hi->ip_address, addrbuf);
 620
 621                        if (ai->ai_canonname)
 622                                sanitize_client(&hi->canon_hostname,
 623                                                ai->ai_canonname);
 624                        else
 625                                strbuf_addbuf(&hi->canon_hostname,
 626                                              &hi->ip_address);
 627
 628                        freeaddrinfo(ai);
 629                }
 630#else
 631                struct hostent *hent;
 632                struct sockaddr_in sa;
 633                char **ap;
 634                static char addrbuf[HOST_NAME_MAX + 1];
 635
 636                hent = gethostbyname(hi->hostname.buf);
 637                if (hent) {
 638                        ap = hent->h_addr_list;
 639                        memset(&sa, 0, sizeof sa);
 640                        sa.sin_family = hent->h_addrtype;
 641                        sa.sin_port = htons(0);
 642                        memcpy(&sa.sin_addr, *ap, hent->h_length);
 643
 644                        inet_ntop(hent->h_addrtype, &sa.sin_addr,
 645                                  addrbuf, sizeof(addrbuf));
 646
 647                        sanitize_client(&hi->canon_hostname, hent->h_name);
 648                        strbuf_addstr(&hi->ip_address, addrbuf);
 649                }
 650#endif
 651                hi->hostname_lookup_done = 1;
 652        }
 653}
 654
 655static void hostinfo_init(struct hostinfo *hi)
 656{
 657        memset(hi, 0, sizeof(*hi));
 658        strbuf_init(&hi->hostname, 0);
 659        strbuf_init(&hi->canon_hostname, 0);
 660        strbuf_init(&hi->ip_address, 0);
 661        strbuf_init(&hi->tcp_port, 0);
 662}
 663
 664static void hostinfo_clear(struct hostinfo *hi)
 665{
 666        strbuf_release(&hi->hostname);
 667        strbuf_release(&hi->canon_hostname);
 668        strbuf_release(&hi->ip_address);
 669        strbuf_release(&hi->tcp_port);
 670}
 671
 672static void set_keep_alive(int sockfd)
 673{
 674        int ka = 1;
 675
 676        if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0) {
 677                if (errno != ENOTSOCK)
 678                        logerror("unable to set SO_KEEPALIVE on socket: %s",
 679                                strerror(errno));
 680        }
 681}
 682
 683static int execute(void)
 684{
 685        char *line = packet_buffer;
 686        int pktlen, len, i;
 687        char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
 688        struct hostinfo hi;
 689
 690        hostinfo_init(&hi);
 691
 692        if (addr)
 693                loginfo("Connection from %s:%s", addr, port);
 694
 695        set_keep_alive(0);
 696        alarm(init_timeout ? init_timeout : timeout);
 697        pktlen = packet_read(0, NULL, NULL, packet_buffer, sizeof(packet_buffer), 0);
 698        alarm(0);
 699
 700        len = strlen(line);
 701        if (pktlen != len)
 702                loginfo("Extended attributes (%d bytes) exist <%.*s>",
 703                        (int) pktlen - len,
 704                        (int) pktlen - len, line + len + 1);
 705        if (len && line[len-1] == '\n') {
 706                line[--len] = 0;
 707                pktlen--;
 708        }
 709
 710        if (len != pktlen)
 711                parse_host_arg(&hi, line + len + 1, pktlen - len - 1);
 712
 713        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 714                struct daemon_service *s = &(daemon_service[i]);
 715                const char *arg;
 716
 717                if (skip_prefix(line, "git-", &arg) &&
 718                    skip_prefix(arg, s->name, &arg) &&
 719                    *arg++ == ' ') {
 720                        /*
 721                         * Note: The directory here is probably context sensitive,
 722                         * and might depend on the actual service being performed.
 723                         */
 724                        int rc = run_service(arg, s, &hi);
 725                        hostinfo_clear(&hi);
 726                        return rc;
 727                }
 728        }
 729
 730        hostinfo_clear(&hi);
 731        logerror("Protocol error: '%s'", line);
 732        return -1;
 733}
 734
 735static int addrcmp(const struct sockaddr_storage *s1,
 736    const struct sockaddr_storage *s2)
 737{
 738        const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 739        const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 740
 741        if (sa1->sa_family != sa2->sa_family)
 742                return sa1->sa_family - sa2->sa_family;
 743        if (sa1->sa_family == AF_INET)
 744                return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 745                    &((struct sockaddr_in *)s2)->sin_addr,
 746                    sizeof(struct in_addr));
 747#ifndef NO_IPV6
 748        if (sa1->sa_family == AF_INET6)
 749                return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 750                    &((struct sockaddr_in6 *)s2)->sin6_addr,
 751                    sizeof(struct in6_addr));
 752#endif
 753        return 0;
 754}
 755
 756static int max_connections = 32;
 757
 758static unsigned int live_children;
 759
 760static struct child {
 761        struct child *next;
 762        struct child_process cld;
 763        struct sockaddr_storage address;
 764} *firstborn;
 765
 766static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
 767{
 768        struct child *newborn, **cradle;
 769
 770        newborn = xcalloc(1, sizeof(*newborn));
 771        live_children++;
 772        memcpy(&newborn->cld, cld, sizeof(*cld));
 773        memcpy(&newborn->address, addr, addrlen);
 774        for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 775                if (!addrcmp(&(*cradle)->address, &newborn->address))
 776                        break;
 777        newborn->next = *cradle;
 778        *cradle = newborn;
 779}
 780
 781/*
 782 * This gets called if the number of connections grows
 783 * past "max_connections".
 784 *
 785 * We kill the newest connection from a duplicate IP.
 786 */
 787static void kill_some_child(void)
 788{
 789        const struct child *blanket, *next;
 790
 791        if (!(blanket = firstborn))
 792                return;
 793
 794        for (; (next = blanket->next); blanket = next)
 795                if (!addrcmp(&blanket->address, &next->address)) {
 796                        kill(blanket->cld.pid, SIGTERM);
 797                        break;
 798                }
 799}
 800
 801static void check_dead_children(void)
 802{
 803        int status;
 804        pid_t pid;
 805
 806        struct child **cradle, *blanket;
 807        for (cradle = &firstborn; (blanket = *cradle);)
 808                if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
 809                        const char *dead = "";
 810                        if (status)
 811                                dead = " (with error)";
 812                        loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 813
 814                        /* remove the child */
 815                        *cradle = blanket->next;
 816                        live_children--;
 817                        child_process_clear(&blanket->cld);
 818                        free(blanket);
 819                } else
 820                        cradle = &blanket->next;
 821}
 822
 823static struct argv_array cld_argv = ARGV_ARRAY_INIT;
 824static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 825{
 826        struct child_process cld = CHILD_PROCESS_INIT;
 827
 828        if (max_connections && live_children >= max_connections) {
 829                kill_some_child();
 830                sleep(1);  /* give it some time to die */
 831                check_dead_children();
 832                if (live_children >= max_connections) {
 833                        close(incoming);
 834                        logerror("Too many children, dropping connection");
 835                        return;
 836                }
 837        }
 838
 839        if (addr->sa_family == AF_INET) {
 840                char buf[128] = "";
 841                struct sockaddr_in *sin_addr = (void *) addr;
 842                inet_ntop(addr->sa_family, &sin_addr->sin_addr, buf, sizeof(buf));
 843                argv_array_pushf(&cld.env_array, "REMOTE_ADDR=%s", buf);
 844                argv_array_pushf(&cld.env_array, "REMOTE_PORT=%d",
 845                                 ntohs(sin_addr->sin_port));
 846#ifndef NO_IPV6
 847        } else if (addr->sa_family == AF_INET6) {
 848                char buf[128] = "";
 849                struct sockaddr_in6 *sin6_addr = (void *) addr;
 850                inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(buf));
 851                argv_array_pushf(&cld.env_array, "REMOTE_ADDR=[%s]", buf);
 852                argv_array_pushf(&cld.env_array, "REMOTE_PORT=%d",
 853                                 ntohs(sin6_addr->sin6_port));
 854#endif
 855        }
 856
 857        cld.argv = cld_argv.argv;
 858        cld.in = incoming;
 859        cld.out = dup(incoming);
 860
 861        if (start_command(&cld))
 862                logerror("unable to fork");
 863        else
 864                add_child(&cld, addr, addrlen);
 865}
 866
 867static void child_handler(int signo)
 868{
 869        /*
 870         * Otherwise empty handler because systemcalls will get interrupted
 871         * upon signal receipt
 872         * SysV needs the handler to be rearmed
 873         */
 874        signal(SIGCHLD, child_handler);
 875}
 876
 877static int set_reuse_addr(int sockfd)
 878{
 879        int on = 1;
 880
 881        if (!reuseaddr)
 882                return 0;
 883        return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 884                          &on, sizeof(on));
 885}
 886
 887struct socketlist {
 888        int *list;
 889        size_t nr;
 890        size_t alloc;
 891};
 892
 893static const char *ip2str(int family, struct sockaddr *sin, socklen_t len)
 894{
 895#ifdef NO_IPV6
 896        static char ip[INET_ADDRSTRLEN];
 897#else
 898        static char ip[INET6_ADDRSTRLEN];
 899#endif
 900
 901        switch (family) {
 902#ifndef NO_IPV6
 903        case AF_INET6:
 904                inet_ntop(family, &((struct sockaddr_in6*)sin)->sin6_addr, ip, len);
 905                break;
 906#endif
 907        case AF_INET:
 908                inet_ntop(family, &((struct sockaddr_in*)sin)->sin_addr, ip, len);
 909                break;
 910        default:
 911                xsnprintf(ip, sizeof(ip), "<unknown>");
 912        }
 913        return ip;
 914}
 915
 916#ifndef NO_IPV6
 917
 918static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 919{
 920        int socknum = 0;
 921        char pbuf[NI_MAXSERV];
 922        struct addrinfo hints, *ai0, *ai;
 923        int gai;
 924        long flags;
 925
 926        xsnprintf(pbuf, sizeof(pbuf), "%d", listen_port);
 927        memset(&hints, 0, sizeof(hints));
 928        hints.ai_family = AF_UNSPEC;
 929        hints.ai_socktype = SOCK_STREAM;
 930        hints.ai_protocol = IPPROTO_TCP;
 931        hints.ai_flags = AI_PASSIVE;
 932
 933        gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 934        if (gai) {
 935                logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
 936                return 0;
 937        }
 938
 939        for (ai = ai0; ai; ai = ai->ai_next) {
 940                int sockfd;
 941
 942                sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 943                if (sockfd < 0)
 944                        continue;
 945                if (sockfd >= FD_SETSIZE) {
 946                        logerror("Socket descriptor too large");
 947                        close(sockfd);
 948                        continue;
 949                }
 950
 951#ifdef IPV6_V6ONLY
 952                if (ai->ai_family == AF_INET6) {
 953                        int on = 1;
 954                        setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 955                                   &on, sizeof(on));
 956                        /* Note: error is not fatal */
 957                }
 958#endif
 959
 960                if (set_reuse_addr(sockfd)) {
 961                        logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 962                        close(sockfd);
 963                        continue;
 964                }
 965
 966                set_keep_alive(sockfd);
 967
 968                if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 969                        logerror("Could not bind to %s: %s",
 970                                 ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 971                                 strerror(errno));
 972                        close(sockfd);
 973                        continue;       /* not fatal */
 974                }
 975                if (listen(sockfd, 5) < 0) {
 976                        logerror("Could not listen to %s: %s",
 977                                 ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 978                                 strerror(errno));
 979                        close(sockfd);
 980                        continue;       /* not fatal */
 981                }
 982
 983                flags = fcntl(sockfd, F_GETFD, 0);
 984                if (flags >= 0)
 985                        fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 986
 987                ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 988                socklist->list[socklist->nr++] = sockfd;
 989                socknum++;
 990        }
 991
 992        freeaddrinfo(ai0);
 993
 994        return socknum;
 995}
 996
 997#else /* NO_IPV6 */
 998
 999static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
1000{
1001        struct sockaddr_in sin;
1002        int sockfd;
1003        long flags;
1004
1005        memset(&sin, 0, sizeof sin);
1006        sin.sin_family = AF_INET;
1007        sin.sin_port = htons(listen_port);
1008
1009        if (listen_addr) {
1010                /* Well, host better be an IP address here. */
1011                if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
1012                        return 0;
1013        } else {
1014                sin.sin_addr.s_addr = htonl(INADDR_ANY);
1015        }
1016
1017        sockfd = socket(AF_INET, SOCK_STREAM, 0);
1018        if (sockfd < 0)
1019                return 0;
1020
1021        if (set_reuse_addr(sockfd)) {
1022                logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
1023                close(sockfd);
1024                return 0;
1025        }
1026
1027        set_keep_alive(sockfd);
1028
1029        if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
1030                logerror("Could not bind to %s: %s",
1031                         ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
1032                         strerror(errno));
1033                close(sockfd);
1034                return 0;
1035        }
1036
1037        if (listen(sockfd, 5) < 0) {
1038                logerror("Could not listen to %s: %s",
1039                         ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
1040                         strerror(errno));
1041                close(sockfd);
1042                return 0;
1043        }
1044
1045        flags = fcntl(sockfd, F_GETFD, 0);
1046        if (flags >= 0)
1047                fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
1048
1049        ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
1050        socklist->list[socklist->nr++] = sockfd;
1051        return 1;
1052}
1053
1054#endif
1055
1056static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
1057{
1058        if (!listen_addr->nr)
1059                setup_named_sock(NULL, listen_port, socklist);
1060        else {
1061                int i, socknum;
1062                for (i = 0; i < listen_addr->nr; i++) {
1063                        socknum = setup_named_sock(listen_addr->items[i].string,
1064                                                   listen_port, socklist);
1065
1066                        if (socknum == 0)
1067                                logerror("unable to allocate any listen sockets for host %s on port %u",
1068                                         listen_addr->items[i].string, listen_port);
1069                }
1070        }
1071}
1072
1073static int service_loop(struct socketlist *socklist)
1074{
1075        struct pollfd *pfd;
1076        int i;
1077
1078        pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
1079
1080        for (i = 0; i < socklist->nr; i++) {
1081                pfd[i].fd = socklist->list[i];
1082                pfd[i].events = POLLIN;
1083        }
1084
1085        signal(SIGCHLD, child_handler);
1086
1087        for (;;) {
1088                int i;
1089
1090                check_dead_children();
1091
1092                if (poll(pfd, socklist->nr, -1) < 0) {
1093                        if (errno != EINTR) {
1094                                logerror("Poll failed, resuming: %s",
1095                                      strerror(errno));
1096                                sleep(1);
1097                        }
1098                        continue;
1099                }
1100
1101                for (i = 0; i < socklist->nr; i++) {
1102                        if (pfd[i].revents & POLLIN) {
1103                                union {
1104                                        struct sockaddr sa;
1105                                        struct sockaddr_in sai;
1106#ifndef NO_IPV6
1107                                        struct sockaddr_in6 sai6;
1108#endif
1109                                } ss;
1110                                socklen_t sslen = sizeof(ss);
1111                                int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
1112                                if (incoming < 0) {
1113                                        switch (errno) {
1114                                        case EAGAIN:
1115                                        case EINTR:
1116                                        case ECONNABORTED:
1117                                                continue;
1118                                        default:
1119                                                die_errno("accept returned");
1120                                        }
1121                                }
1122                                handle(incoming, &ss.sa, sslen);
1123                        }
1124                }
1125        }
1126}
1127
1128#ifdef NO_POSIX_GOODIES
1129
1130struct credentials;
1131
1132static void drop_privileges(struct credentials *cred)
1133{
1134        /* nothing */
1135}
1136
1137static struct credentials *prepare_credentials(const char *user_name,
1138    const char *group_name)
1139{
1140        die("--user not supported on this platform");
1141}
1142
1143#else
1144
1145struct credentials {
1146        struct passwd *pass;
1147        gid_t gid;
1148};
1149
1150static void drop_privileges(struct credentials *cred)
1151{
1152        if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
1153            setgid (cred->gid) || setuid(cred->pass->pw_uid)))
1154                die("cannot drop privileges");
1155}
1156
1157static struct credentials *prepare_credentials(const char *user_name,
1158    const char *group_name)
1159{
1160        static struct credentials c;
1161
1162        c.pass = getpwnam(user_name);
1163        if (!c.pass)
1164                die("user not found - %s", user_name);
1165
1166        if (!group_name)
1167                c.gid = c.pass->pw_gid;
1168        else {
1169                struct group *group = getgrnam(group_name);
1170                if (!group)
1171                        die("group not found - %s", group_name);
1172
1173                c.gid = group->gr_gid;
1174        }
1175
1176        return &c;
1177}
1178#endif
1179
1180static int serve(struct string_list *listen_addr, int listen_port,
1181    struct credentials *cred)
1182{
1183        struct socketlist socklist = { NULL, 0, 0 };
1184
1185        socksetup(listen_addr, listen_port, &socklist);
1186        if (socklist.nr == 0)
1187                die("unable to allocate any listen sockets on port %u",
1188                    listen_port);
1189
1190        drop_privileges(cred);
1191
1192        loginfo("Ready to rumble");
1193
1194        return service_loop(&socklist);
1195}
1196
1197int main(int argc, char **argv)
1198{
1199        int listen_port = 0;
1200        struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1201        int serve_mode = 0, inetd_mode = 0;
1202        const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1203        int detach = 0;
1204        struct credentials *cred = NULL;
1205        int i;
1206
1207        git_setup_gettext();
1208
1209        git_extract_argv0_path(argv[0]);
1210
1211        for (i = 1; i < argc; i++) {
1212                char *arg = argv[i];
1213                const char *v;
1214
1215                if (skip_prefix(arg, "--listen=", &v)) {
1216                        string_list_append(&listen_addr, xstrdup_tolower(v));
1217                        continue;
1218                }
1219                if (skip_prefix(arg, "--port=", &v)) {
1220                        char *end;
1221                        unsigned long n;
1222                        n = strtoul(v, &end, 0);
1223                        if (*v && !*end) {
1224                                listen_port = n;
1225                                continue;
1226                        }
1227                }
1228                if (!strcmp(arg, "--serve")) {
1229                        serve_mode = 1;
1230                        continue;
1231                }
1232                if (!strcmp(arg, "--inetd")) {
1233                        inetd_mode = 1;
1234                        log_syslog = 1;
1235                        continue;
1236                }
1237                if (!strcmp(arg, "--verbose")) {
1238                        verbose = 1;
1239                        continue;
1240                }
1241                if (!strcmp(arg, "--syslog")) {
1242                        log_syslog = 1;
1243                        continue;
1244                }
1245                if (!strcmp(arg, "--export-all")) {
1246                        export_all_trees = 1;
1247                        continue;
1248                }
1249                if (skip_prefix(arg, "--access-hook=", &v)) {
1250                        access_hook = v;
1251                        continue;
1252                }
1253                if (skip_prefix(arg, "--timeout=", &v)) {
1254                        timeout = atoi(v);
1255                        continue;
1256                }
1257                if (skip_prefix(arg, "--init-timeout=", &v)) {
1258                        init_timeout = atoi(v);
1259                        continue;
1260                }
1261                if (skip_prefix(arg, "--max-connections=", &v)) {
1262                        max_connections = atoi(v);
1263                        if (max_connections < 0)
1264                                max_connections = 0;            /* unlimited */
1265                        continue;
1266                }
1267                if (!strcmp(arg, "--strict-paths")) {
1268                        strict_paths = 1;
1269                        continue;
1270                }
1271                if (skip_prefix(arg, "--base-path=", &v)) {
1272                        base_path = v;
1273                        continue;
1274                }
1275                if (!strcmp(arg, "--base-path-relaxed")) {
1276                        base_path_relaxed = 1;
1277                        continue;
1278                }
1279                if (skip_prefix(arg, "--interpolated-path=", &v)) {
1280                        interpolated_path = v;
1281                        continue;
1282                }
1283                if (!strcmp(arg, "--reuseaddr")) {
1284                        reuseaddr = 1;
1285                        continue;
1286                }
1287                if (!strcmp(arg, "--user-path")) {
1288                        user_path = "";
1289                        continue;
1290                }
1291                if (skip_prefix(arg, "--user-path=", &v)) {
1292                        user_path = v;
1293                        continue;
1294                }
1295                if (skip_prefix(arg, "--pid-file=", &v)) {
1296                        pid_file = v;
1297                        continue;
1298                }
1299                if (!strcmp(arg, "--detach")) {
1300                        detach = 1;
1301                        log_syslog = 1;
1302                        continue;
1303                }
1304                if (skip_prefix(arg, "--user=", &v)) {
1305                        user_name = v;
1306                        continue;
1307                }
1308                if (skip_prefix(arg, "--group=", &v)) {
1309                        group_name = v;
1310                        continue;
1311                }
1312                if (skip_prefix(arg, "--enable=", &v)) {
1313                        enable_service(v, 1);
1314                        continue;
1315                }
1316                if (skip_prefix(arg, "--disable=", &v)) {
1317                        enable_service(v, 0);
1318                        continue;
1319                }
1320                if (skip_prefix(arg, "--allow-override=", &v)) {
1321                        make_service_overridable(v, 1);
1322                        continue;
1323                }
1324                if (skip_prefix(arg, "--forbid-override=", &v)) {
1325                        make_service_overridable(v, 0);
1326                        continue;
1327                }
1328                if (!strcmp(arg, "--informative-errors")) {
1329                        informative_errors = 1;
1330                        continue;
1331                }
1332                if (!strcmp(arg, "--no-informative-errors")) {
1333                        informative_errors = 0;
1334                        continue;
1335                }
1336                if (!strcmp(arg, "--")) {
1337                        ok_paths = &argv[i+1];
1338                        break;
1339                } else if (arg[0] != '-') {
1340                        ok_paths = &argv[i];
1341                        break;
1342                }
1343
1344                usage(daemon_usage);
1345        }
1346
1347        if (log_syslog) {
1348                openlog("git-daemon", LOG_PID, LOG_DAEMON);
1349                set_die_routine(daemon_die);
1350        } else
1351                /* avoid splitting a message in the middle */
1352                setvbuf(stderr, NULL, _IOFBF, 4096);
1353
1354        if (inetd_mode && (detach || group_name || user_name))
1355                die("--detach, --user and --group are incompatible with --inetd");
1356
1357        if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1358                die("--listen= and --port= are incompatible with --inetd");
1359        else if (listen_port == 0)
1360                listen_port = DEFAULT_GIT_PORT;
1361
1362        if (group_name && !user_name)
1363                die("--group supplied without --user");
1364
1365        if (user_name)
1366                cred = prepare_credentials(user_name, group_name);
1367
1368        if (strict_paths && (!ok_paths || !*ok_paths))
1369                die("option --strict-paths requires a whitelist");
1370
1371        if (base_path && !is_directory(base_path))
1372                die("base-path '%s' does not exist or is not a directory",
1373                    base_path);
1374
1375        if (inetd_mode) {
1376                if (!freopen("/dev/null", "w", stderr))
1377                        die_errno("failed to redirect stderr to /dev/null");
1378        }
1379
1380        if (inetd_mode || serve_mode)
1381                return execute();
1382
1383        if (detach) {
1384                if (daemonize())
1385                        die("--detach not supported on this platform");
1386        } else
1387                sanitize_stdfds();
1388
1389        if (pid_file)
1390                write_file(pid_file, "%"PRIuMAX, (uintmax_t) getpid());
1391
1392        /* prepare argv for serving-processes */
1393        argv_array_push(&cld_argv, argv[0]); /* git-daemon */
1394        argv_array_push(&cld_argv, "--serve");
1395        for (i = 1; i < argc; ++i)
1396                argv_array_push(&cld_argv, argv[i]);
1397
1398        return serve(&listen_addr, listen_port, cred);
1399}