Andrew's git / gitweb.git / daemon.c
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daemon.con commit gitweb: hack around CGI's list-context param() handling (13dbf46)
   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                if (hent) {
 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                }
 591#endif
 592        }
 593}
 594
 595
 596static int execute(void)
 597{
 598        char *line = packet_buffer;
 599        int pktlen, len, i;
 600        char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
 601
 602        if (addr)
 603                loginfo("Connection from %s:%s", addr, port);
 604
 605        alarm(init_timeout ? init_timeout : timeout);
 606        pktlen = packet_read(0, NULL, NULL, packet_buffer, sizeof(packet_buffer), 0);
 607        alarm(0);
 608
 609        len = strlen(line);
 610        if (pktlen != len)
 611                loginfo("Extended attributes (%d bytes) exist <%.*s>",
 612                        (int) pktlen - len,
 613                        (int) pktlen - len, line + len + 1);
 614        if (len && line[len-1] == '\n') {
 615                line[--len] = 0;
 616                pktlen--;
 617        }
 618
 619        free(hostname);
 620        free(canon_hostname);
 621        free(ip_address);
 622        free(tcp_port);
 623        hostname = canon_hostname = ip_address = tcp_port = NULL;
 624
 625        if (len != pktlen)
 626                parse_host_arg(line + len + 1, pktlen - len - 1);
 627
 628        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 629                struct daemon_service *s = &(daemon_service[i]);
 630                const char *arg;
 631
 632                if (skip_prefix(line, "git-", &arg) &&
 633                    skip_prefix(arg, s->name, &arg) &&
 634                    *arg++ == ' ') {
 635                        /*
 636                         * Note: The directory here is probably context sensitive,
 637                         * and might depend on the actual service being performed.
 638                         */
 639                        return run_service(arg, s);
 640                }
 641        }
 642
 643        logerror("Protocol error: '%s'", line);
 644        return -1;
 645}
 646
 647static int addrcmp(const struct sockaddr_storage *s1,
 648    const struct sockaddr_storage *s2)
 649{
 650        const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 651        const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 652
 653        if (sa1->sa_family != sa2->sa_family)
 654                return sa1->sa_family - sa2->sa_family;
 655        if (sa1->sa_family == AF_INET)
 656                return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 657                    &((struct sockaddr_in *)s2)->sin_addr,
 658                    sizeof(struct in_addr));
 659#ifndef NO_IPV6
 660        if (sa1->sa_family == AF_INET6)
 661                return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 662                    &((struct sockaddr_in6 *)s2)->sin6_addr,
 663                    sizeof(struct in6_addr));
 664#endif
 665        return 0;
 666}
 667
 668static int max_connections = 32;
 669
 670static unsigned int live_children;
 671
 672static struct child {
 673        struct child *next;
 674        struct child_process cld;
 675        struct sockaddr_storage address;
 676} *firstborn;
 677
 678static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
 679{
 680        struct child *newborn, **cradle;
 681
 682        newborn = xcalloc(1, sizeof(*newborn));
 683        live_children++;
 684        memcpy(&newborn->cld, cld, sizeof(*cld));
 685        memcpy(&newborn->address, addr, addrlen);
 686        for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 687                if (!addrcmp(&(*cradle)->address, &newborn->address))
 688                        break;
 689        newborn->next = *cradle;
 690        *cradle = newborn;
 691}
 692
 693/*
 694 * This gets called if the number of connections grows
 695 * past "max_connections".
 696 *
 697 * We kill the newest connection from a duplicate IP.
 698 */
 699static void kill_some_child(void)
 700{
 701        const struct child *blanket, *next;
 702
 703        if (!(blanket = firstborn))
 704                return;
 705
 706        for (; (next = blanket->next); blanket = next)
 707                if (!addrcmp(&blanket->address, &next->address)) {
 708                        kill(blanket->cld.pid, SIGTERM);
 709                        break;
 710                }
 711}
 712
 713static void check_dead_children(void)
 714{
 715        int status;
 716        pid_t pid;
 717
 718        struct child **cradle, *blanket;
 719        for (cradle = &firstborn; (blanket = *cradle);)
 720                if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
 721                        const char *dead = "";
 722                        if (status)
 723                                dead = " (with error)";
 724                        loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 725
 726                        /* remove the child */
 727                        *cradle = blanket->next;
 728                        live_children--;
 729                        free(blanket);
 730                } else
 731                        cradle = &blanket->next;
 732}
 733
 734static char **cld_argv;
 735static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 736{
 737        struct child_process cld = { NULL };
 738        char addrbuf[300] = "REMOTE_ADDR=", portbuf[300];
 739        char *env[] = { addrbuf, portbuf, NULL };
 740
 741        if (max_connections && live_children >= max_connections) {
 742                kill_some_child();
 743                sleep(1);  /* give it some time to die */
 744                check_dead_children();
 745                if (live_children >= max_connections) {
 746                        close(incoming);
 747                        logerror("Too many children, dropping connection");
 748                        return;
 749                }
 750        }
 751
 752        if (addr->sa_family == AF_INET) {
 753                struct sockaddr_in *sin_addr = (void *) addr;
 754                inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf + 12,
 755                    sizeof(addrbuf) - 12);
 756                snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 757                    ntohs(sin_addr->sin_port));
 758#ifndef NO_IPV6
 759        } else if (addr->sa_family == AF_INET6) {
 760                struct sockaddr_in6 *sin6_addr = (void *) addr;
 761
 762                char *buf = addrbuf + 12;
 763                *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 764                inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf,
 765                    sizeof(addrbuf) - 13);
 766                strcat(buf, "]");
 767
 768                snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 769                    ntohs(sin6_addr->sin6_port));
 770#endif
 771        }
 772
 773        cld.env = (const char **)env;
 774        cld.argv = (const char **)cld_argv;
 775        cld.in = incoming;
 776        cld.out = dup(incoming);
 777
 778        if (start_command(&cld))
 779                logerror("unable to fork");
 780        else
 781                add_child(&cld, addr, addrlen);
 782}
 783
 784static void child_handler(int signo)
 785{
 786        /*
 787         * Otherwise empty handler because systemcalls will get interrupted
 788         * upon signal receipt
 789         * SysV needs the handler to be rearmed
 790         */
 791        signal(SIGCHLD, child_handler);
 792}
 793
 794static int set_reuse_addr(int sockfd)
 795{
 796        int on = 1;
 797
 798        if (!reuseaddr)
 799                return 0;
 800        return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 801                          &on, sizeof(on));
 802}
 803
 804struct socketlist {
 805        int *list;
 806        size_t nr;
 807        size_t alloc;
 808};
 809
 810static const char *ip2str(int family, struct sockaddr *sin, socklen_t len)
 811{
 812#ifdef NO_IPV6
 813        static char ip[INET_ADDRSTRLEN];
 814#else
 815        static char ip[INET6_ADDRSTRLEN];
 816#endif
 817
 818        switch (family) {
 819#ifndef NO_IPV6
 820        case AF_INET6:
 821                inet_ntop(family, &((struct sockaddr_in6*)sin)->sin6_addr, ip, len);
 822                break;
 823#endif
 824        case AF_INET:
 825                inet_ntop(family, &((struct sockaddr_in*)sin)->sin_addr, ip, len);
 826                break;
 827        default:
 828                strcpy(ip, "<unknown>");
 829        }
 830        return ip;
 831}
 832
 833#ifndef NO_IPV6
 834
 835static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 836{
 837        int socknum = 0;
 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
 907        freeaddrinfo(ai0);
 908
 909        return socknum;
 910}
 911
 912#else /* NO_IPV6 */
 913
 914static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 915{
 916        struct sockaddr_in sin;
 917        int sockfd;
 918        long flags;
 919
 920        memset(&sin, 0, sizeof sin);
 921        sin.sin_family = AF_INET;
 922        sin.sin_port = htons(listen_port);
 923
 924        if (listen_addr) {
 925                /* Well, host better be an IP address here. */
 926                if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 927                        return 0;
 928        } else {
 929                sin.sin_addr.s_addr = htonl(INADDR_ANY);
 930        }
 931
 932        sockfd = socket(AF_INET, SOCK_STREAM, 0);
 933        if (sockfd < 0)
 934                return 0;
 935
 936        if (set_reuse_addr(sockfd)) {
 937                logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 938                close(sockfd);
 939                return 0;
 940        }
 941
 942        if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 943                logerror("Could not bind to %s: %s",
 944                         ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
 945                         strerror(errno));
 946                close(sockfd);
 947                return 0;
 948        }
 949
 950        if (listen(sockfd, 5) < 0) {
 951                logerror("Could not listen to %s: %s",
 952                         ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
 953                         strerror(errno));
 954                close(sockfd);
 955                return 0;
 956        }
 957
 958        flags = fcntl(sockfd, F_GETFD, 0);
 959        if (flags >= 0)
 960                fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 961
 962        ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 963        socklist->list[socklist->nr++] = sockfd;
 964        return 1;
 965}
 966
 967#endif
 968
 969static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
 970{
 971        if (!listen_addr->nr)
 972                setup_named_sock(NULL, listen_port, socklist);
 973        else {
 974                int i, socknum;
 975                for (i = 0; i < listen_addr->nr; i++) {
 976                        socknum = setup_named_sock(listen_addr->items[i].string,
 977                                                   listen_port, socklist);
 978
 979                        if (socknum == 0)
 980                                logerror("unable to allocate any listen sockets for host %s on port %u",
 981                                         listen_addr->items[i].string, listen_port);
 982                }
 983        }
 984}
 985
 986static int service_loop(struct socketlist *socklist)
 987{
 988        struct pollfd *pfd;
 989        int i;
 990
 991        pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
 992
 993        for (i = 0; i < socklist->nr; i++) {
 994                pfd[i].fd = socklist->list[i];
 995                pfd[i].events = POLLIN;
 996        }
 997
 998        signal(SIGCHLD, child_handler);
 999
1000        for (;;) {
1001                int i;
1002
1003                check_dead_children();
1004
1005                if (poll(pfd, socklist->nr, -1) < 0) {
1006                        if (errno != EINTR) {
1007                                logerror("Poll failed, resuming: %s",
1008                                      strerror(errno));
1009                                sleep(1);
1010                        }
1011                        continue;
1012                }
1013
1014                for (i = 0; i < socklist->nr; i++) {
1015                        if (pfd[i].revents & POLLIN) {
1016                                union {
1017                                        struct sockaddr sa;
1018                                        struct sockaddr_in sai;
1019#ifndef NO_IPV6
1020                                        struct sockaddr_in6 sai6;
1021#endif
1022                                } ss;
1023                                socklen_t sslen = sizeof(ss);
1024                                int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
1025                                if (incoming < 0) {
1026                                        switch (errno) {
1027                                        case EAGAIN:
1028                                        case EINTR:
1029                                        case ECONNABORTED:
1030                                                continue;
1031                                        default:
1032                                                die_errno("accept returned");
1033                                        }
1034                                }
1035                                handle(incoming, &ss.sa, sslen);
1036                        }
1037                }
1038        }
1039}
1040
1041#ifdef NO_POSIX_GOODIES
1042
1043struct credentials;
1044
1045static void drop_privileges(struct credentials *cred)
1046{
1047        /* nothing */
1048}
1049
1050static struct credentials *prepare_credentials(const char *user_name,
1051    const char *group_name)
1052{
1053        die("--user not supported on this platform");
1054}
1055
1056#else
1057
1058struct credentials {
1059        struct passwd *pass;
1060        gid_t gid;
1061};
1062
1063static void drop_privileges(struct credentials *cred)
1064{
1065        if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
1066            setgid (cred->gid) || setuid(cred->pass->pw_uid)))
1067                die("cannot drop privileges");
1068}
1069
1070static struct credentials *prepare_credentials(const char *user_name,
1071    const char *group_name)
1072{
1073        static struct credentials c;
1074
1075        c.pass = getpwnam(user_name);
1076        if (!c.pass)
1077                die("user not found - %s", user_name);
1078
1079        if (!group_name)
1080                c.gid = c.pass->pw_gid;
1081        else {
1082                struct group *group = getgrnam(group_name);
1083                if (!group)
1084                        die("group not found - %s", group_name);
1085
1086                c.gid = group->gr_gid;
1087        }
1088
1089        return &c;
1090}
1091#endif
1092
1093static void store_pid(const char *path)
1094{
1095        FILE *f = fopen(path, "w");
1096        if (!f)
1097                die_errno("cannot open pid file '%s'", path);
1098        if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
1099                die_errno("failed to write pid file '%s'", path);
1100}
1101
1102static int serve(struct string_list *listen_addr, int listen_port,
1103    struct credentials *cred)
1104{
1105        struct socketlist socklist = { NULL, 0, 0 };
1106
1107        socksetup(listen_addr, listen_port, &socklist);
1108        if (socklist.nr == 0)
1109                die("unable to allocate any listen sockets on port %u",
1110                    listen_port);
1111
1112        drop_privileges(cred);
1113
1114        loginfo("Ready to rumble");
1115
1116        return service_loop(&socklist);
1117}
1118
1119int main(int argc, char **argv)
1120{
1121        int listen_port = 0;
1122        struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1123        int serve_mode = 0, inetd_mode = 0;
1124        const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1125        int detach = 0;
1126        struct credentials *cred = NULL;
1127        int i;
1128
1129        git_setup_gettext();
1130
1131        git_extract_argv0_path(argv[0]);
1132
1133        for (i = 1; i < argc; i++) {
1134                char *arg = argv[i];
1135                const char *v;
1136
1137                if (skip_prefix(arg, "--listen=", &v)) {
1138                        string_list_append(&listen_addr, xstrdup_tolower(v));
1139                        continue;
1140                }
1141                if (skip_prefix(arg, "--port=", &v)) {
1142                        char *end;
1143                        unsigned long n;
1144                        n = strtoul(v, &end, 0);
1145                        if (*v && !*end) {
1146                                listen_port = n;
1147                                continue;
1148                        }
1149                }
1150                if (!strcmp(arg, "--serve")) {
1151                        serve_mode = 1;
1152                        continue;
1153                }
1154                if (!strcmp(arg, "--inetd")) {
1155                        inetd_mode = 1;
1156                        log_syslog = 1;
1157                        continue;
1158                }
1159                if (!strcmp(arg, "--verbose")) {
1160                        verbose = 1;
1161                        continue;
1162                }
1163                if (!strcmp(arg, "--syslog")) {
1164                        log_syslog = 1;
1165                        continue;
1166                }
1167                if (!strcmp(arg, "--export-all")) {
1168                        export_all_trees = 1;
1169                        continue;
1170                }
1171                if (skip_prefix(arg, "--access-hook=", &v)) {
1172                        access_hook = v;
1173                        continue;
1174                }
1175                if (skip_prefix(arg, "--timeout=", &v)) {
1176                        timeout = atoi(v);
1177                        continue;
1178                }
1179                if (skip_prefix(arg, "--init-timeout=", &v)) {
1180                        init_timeout = atoi(v);
1181                        continue;
1182                }
1183                if (skip_prefix(arg, "--max-connections=", &v)) {
1184                        max_connections = atoi(v);
1185                        if (max_connections < 0)
1186                                max_connections = 0;            /* unlimited */
1187                        continue;
1188                }
1189                if (!strcmp(arg, "--strict-paths")) {
1190                        strict_paths = 1;
1191                        continue;
1192                }
1193                if (skip_prefix(arg, "--base-path=", &v)) {
1194                        base_path = v;
1195                        continue;
1196                }
1197                if (!strcmp(arg, "--base-path-relaxed")) {
1198                        base_path_relaxed = 1;
1199                        continue;
1200                }
1201                if (skip_prefix(arg, "--interpolated-path=", &v)) {
1202                        interpolated_path = v;
1203                        continue;
1204                }
1205                if (!strcmp(arg, "--reuseaddr")) {
1206                        reuseaddr = 1;
1207                        continue;
1208                }
1209                if (!strcmp(arg, "--user-path")) {
1210                        user_path = "";
1211                        continue;
1212                }
1213                if (skip_prefix(arg, "--user-path=", &v)) {
1214                        user_path = v;
1215                        continue;
1216                }
1217                if (skip_prefix(arg, "--pid-file=", &v)) {
1218                        pid_file = v;
1219                        continue;
1220                }
1221                if (!strcmp(arg, "--detach")) {
1222                        detach = 1;
1223                        log_syslog = 1;
1224                        continue;
1225                }
1226                if (skip_prefix(arg, "--user=", &v)) {
1227                        user_name = v;
1228                        continue;
1229                }
1230                if (skip_prefix(arg, "--group=", &v)) {
1231                        group_name = v;
1232                        continue;
1233                }
1234                if (skip_prefix(arg, "--enable=", &v)) {
1235                        enable_service(v, 1);
1236                        continue;
1237                }
1238                if (skip_prefix(arg, "--disable=", &v)) {
1239                        enable_service(v, 0);
1240                        continue;
1241                }
1242                if (skip_prefix(arg, "--allow-override=", &v)) {
1243                        make_service_overridable(v, 1);
1244                        continue;
1245                }
1246                if (skip_prefix(arg, "--forbid-override=", &v)) {
1247                        make_service_overridable(v, 0);
1248                        continue;
1249                }
1250                if (!strcmp(arg, "--informative-errors")) {
1251                        informative_errors = 1;
1252                        continue;
1253                }
1254                if (!strcmp(arg, "--no-informative-errors")) {
1255                        informative_errors = 0;
1256                        continue;
1257                }
1258                if (!strcmp(arg, "--")) {
1259                        ok_paths = &argv[i+1];
1260                        break;
1261                } else if (arg[0] != '-') {
1262                        ok_paths = &argv[i];
1263                        break;
1264                }
1265
1266                usage(daemon_usage);
1267        }
1268
1269        if (log_syslog) {
1270                openlog("git-daemon", LOG_PID, LOG_DAEMON);
1271                set_die_routine(daemon_die);
1272        } else
1273                /* avoid splitting a message in the middle */
1274                setvbuf(stderr, NULL, _IOFBF, 4096);
1275
1276        if (inetd_mode && (detach || group_name || user_name))
1277                die("--detach, --user and --group are incompatible with --inetd");
1278
1279        if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1280                die("--listen= and --port= are incompatible with --inetd");
1281        else if (listen_port == 0)
1282                listen_port = DEFAULT_GIT_PORT;
1283
1284        if (group_name && !user_name)
1285                die("--group supplied without --user");
1286
1287        if (user_name)
1288                cred = prepare_credentials(user_name, group_name);
1289
1290        if (strict_paths && (!ok_paths || !*ok_paths))
1291                die("option --strict-paths requires a whitelist");
1292
1293        if (base_path && !is_directory(base_path))
1294                die("base-path '%s' does not exist or is not a directory",
1295                    base_path);
1296
1297        if (inetd_mode) {
1298                if (!freopen("/dev/null", "w", stderr))
1299                        die_errno("failed to redirect stderr to /dev/null");
1300        }
1301
1302        if (inetd_mode || serve_mode)
1303                return execute();
1304
1305        if (detach) {
1306                if (daemonize())
1307                        die("--detach not supported on this platform");
1308        } else
1309                sanitize_stdfds();
1310
1311        if (pid_file)
1312                store_pid(pid_file);
1313
1314        /* prepare argv for serving-processes */
1315        cld_argv = xmalloc(sizeof (char *) * (argc + 2));
1316        cld_argv[0] = argv[0];  /* git-daemon */
1317        cld_argv[1] = "--serve";
1318        for (i = 1; i < argc; ++i)
1319                cld_argv[i+1] = argv[i];
1320        cld_argv[argc+1] = NULL;
1321
1322        return serve(&listen_addr, listen_port, cred);
1323}