Andrew's git / gitweb.git / daemon.c
?
daemon.con commit Makefile: add comment on CYGWIN_V15_WIN32API (49a370d)
   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#ifndef NI_MAXSERV
  13#define NI_MAXSERV 32
  14#endif
  15
  16#ifdef NO_INITGROUPS
  17#define initgroups(x, y) (0) /* nothing */
  18#endif
  19
  20static int log_syslog;
  21static int verbose;
  22static int reuseaddr;
  23static int informative_errors;
  24
  25static const char daemon_usage[] =
  26"git daemon [--verbose] [--syslog] [--export-all]\n"
  27"           [--timeout=<n>] [--init-timeout=<n>] [--max-connections=<n>]\n"
  28"           [--strict-paths] [--base-path=<path>] [--base-path-relaxed]\n"
  29"           [--user-path | --user-path=<path>]\n"
  30"           [--interpolated-path=<path>]\n"
  31"           [--reuseaddr] [--pid-file=<file>]\n"
  32"           [--(enable|disable|allow-override|forbid-override)=<service>]\n"
  33"           [--access-hook=<path>]\n"
  34"           [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
  35"                      [--detach] [--user=<user> [--group=<group>]]\n"
  36"           [<directory>...]";
  37
  38/* List of acceptable pathname prefixes */
  39static char **ok_paths;
  40static int strict_paths;
  41
  42/* If this is set, git-daemon-export-ok is not required */
  43static int export_all_trees;
  44
  45/* Take all paths relative to this one if non-NULL */
  46static char *base_path;
  47static char *interpolated_path;
  48static int base_path_relaxed;
  49
  50/* Flag indicating client sent extra args. */
  51static int saw_extended_args;
  52
  53/* If defined, ~user notation is allowed and the string is inserted
  54 * after ~user/.  E.g. a request to git://host/~alice/frotz would
  55 * go to /home/alice/pub_git/frotz with --user-path=pub_git.
  56 */
  57static const char *user_path;
  58
  59/* Timeout, and initial timeout */
  60static unsigned int timeout;
  61static unsigned int init_timeout;
  62
  63static char *hostname;
  64static char *canon_hostname;
  65static char *ip_address;
  66static char *tcp_port;
  67
  68static void logreport(int priority, const char *err, va_list params)
  69{
  70        if (log_syslog) {
  71                char buf[1024];
  72                vsnprintf(buf, sizeof(buf), err, params);
  73                syslog(priority, "%s", buf);
  74        } else {
  75                /*
  76                 * Since stderr is set to buffered mode, the
  77                 * logging of different processes will not overlap
  78                 * unless they overflow the (rather big) buffers.
  79                 */
  80                fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
  81                vfprintf(stderr, err, params);
  82                fputc('\n', stderr);
  83                fflush(stderr);
  84        }
  85}
  86
  87__attribute__((format (printf, 1, 2)))
  88static void logerror(const char *err, ...)
  89{
  90        va_list params;
  91        va_start(params, err);
  92        logreport(LOG_ERR, err, params);
  93        va_end(params);
  94}
  95
  96__attribute__((format (printf, 1, 2)))
  97static void loginfo(const char *err, ...)
  98{
  99        va_list params;
 100        if (!verbose)
 101                return;
 102        va_start(params, err);
 103        logreport(LOG_INFO, err, params);
 104        va_end(params);
 105}
 106
 107static void NORETURN daemon_die(const char *err, va_list params)
 108{
 109        logreport(LOG_ERR, err, params);
 110        exit(1);
 111}
 112
 113static const char *path_ok(char *directory)
 114{
 115        static char rpath[PATH_MAX];
 116        static char interp_path[PATH_MAX];
 117        const char *path;
 118        char *dir;
 119
 120        dir = directory;
 121
 122        if (daemon_avoid_alias(dir)) {
 123                logerror("'%s': aliased", dir);
 124                return NULL;
 125        }
 126
 127        if (*dir == '~') {
 128                if (!user_path) {
 129                        logerror("'%s': User-path not allowed", dir);
 130                        return NULL;
 131                }
 132                if (*user_path) {
 133                        /* Got either "~alice" or "~alice/foo";
 134                         * rewrite them to "~alice/%s" or
 135                         * "~alice/%s/foo".
 136                         */
 137                        int namlen, restlen = strlen(dir);
 138                        char *slash = strchr(dir, '/');
 139                        if (!slash)
 140                                slash = dir + restlen;
 141                        namlen = slash - dir;
 142                        restlen -= namlen;
 143                        loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
 144                        snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
 145                                 namlen, dir, user_path, restlen, slash);
 146                        dir = rpath;
 147                }
 148        }
 149        else if (interpolated_path && saw_extended_args) {
 150                struct strbuf expanded_path = STRBUF_INIT;
 151                struct strbuf_expand_dict_entry dict[6];
 152
 153                dict[0].placeholder = "H"; dict[0].value = hostname;
 154                dict[1].placeholder = "CH"; dict[1].value = canon_hostname;
 155                dict[2].placeholder = "IP"; dict[2].value = ip_address;
 156                dict[3].placeholder = "P"; dict[3].value = tcp_port;
 157                dict[4].placeholder = "D"; dict[4].value = directory;
 158                dict[5].placeholder = NULL; dict[5].value = NULL;
 159                if (*dir != '/') {
 160                        /* Allow only absolute */
 161                        logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 162                        return NULL;
 163                }
 164
 165                strbuf_expand(&expanded_path, interpolated_path,
 166                                strbuf_expand_dict_cb, &dict);
 167                strlcpy(interp_path, expanded_path.buf, PATH_MAX);
 168                strbuf_release(&expanded_path);
 169                loginfo("Interpolated dir '%s'", interp_path);
 170
 171                dir = interp_path;
 172        }
 173        else if (base_path) {
 174                if (*dir != '/') {
 175                        /* Allow only absolute */
 176                        logerror("'%s': Non-absolute path denied (base-path active)", dir);
 177                        return NULL;
 178                }
 179                snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
 180                dir = rpath;
 181        }
 182
 183        path = enter_repo(dir, strict_paths);
 184        if (!path && base_path && base_path_relaxed) {
 185                /*
 186                 * if we fail and base_path_relaxed is enabled, try without
 187                 * prefixing the base path
 188                 */
 189                dir = directory;
 190                path = enter_repo(dir, strict_paths);
 191        }
 192
 193        if (!path) {
 194                logerror("'%s' does not appear to be a git repository", dir);
 195                return NULL;
 196        }
 197
 198        if ( ok_paths && *ok_paths ) {
 199                char **pp;
 200                int pathlen = strlen(path);
 201
 202                /* The validation is done on the paths after enter_repo
 203                 * appends optional {.git,.git/.git} and friends, but
 204                 * it does not use getcwd().  So if your /pub is
 205                 * a symlink to /mnt/pub, you can whitelist /pub and
 206                 * do not have to say /mnt/pub.
 207                 * Do not say /pub/.
 208                 */
 209                for ( pp = ok_paths ; *pp ; pp++ ) {
 210                        int len = strlen(*pp);
 211                        if (len <= pathlen &&
 212                            !memcmp(*pp, path, len) &&
 213                            (path[len] == '\0' ||
 214                             (!strict_paths && path[len] == '/')))
 215                                return path;
 216                }
 217        }
 218        else {
 219                /* be backwards compatible */
 220                if (!strict_paths)
 221                        return path;
 222        }
 223
 224        logerror("'%s': not in whitelist", path);
 225        return NULL;            /* Fallthrough. Deny by default */
 226}
 227
 228typedef int (*daemon_service_fn)(void);
 229struct daemon_service {
 230        const char *name;
 231        const char *config_name;
 232        daemon_service_fn fn;
 233        int enabled;
 234        int overridable;
 235};
 236
 237static struct daemon_service *service_looking_at;
 238static int service_enabled;
 239
 240static int git_daemon_config(const char *var, const char *value, void *cb)
 241{
 242        if (!prefixcmp(var, "daemon.") &&
 243            !strcmp(var + 7, service_looking_at->config_name)) {
 244                service_enabled = git_config_bool(var, value);
 245                return 0;
 246        }
 247
 248        /* we are not interested in parsing any other configuration here */
 249        return 0;
 250}
 251
 252static int daemon_error(const char *dir, const char *msg)
 253{
 254        if (!informative_errors)
 255                msg = "access denied or repository not exported";
 256        packet_write(1, "ERR %s: %s", msg, dir);
 257        return -1;
 258}
 259
 260static char *access_hook;
 261
 262static int run_access_hook(struct daemon_service *service, const char *dir, const char *path)
 263{
 264        struct child_process child;
 265        struct strbuf buf = STRBUF_INIT;
 266        const char *argv[8];
 267        const char **arg = argv;
 268        char *eol;
 269        int seen_errors = 0;
 270
 271#define STRARG(x) ((x) ? (x) : "")
 272        *arg++ = access_hook;
 273        *arg++ = service->name;
 274        *arg++ = path;
 275        *arg++ = STRARG(hostname);
 276        *arg++ = STRARG(canon_hostname);
 277        *arg++ = STRARG(ip_address);
 278        *arg++ = STRARG(tcp_port);
 279        *arg = NULL;
 280#undef STRARG
 281
 282        memset(&child, 0, sizeof(child));
 283        child.use_shell = 1;
 284        child.argv = argv;
 285        child.no_stdin = 1;
 286        child.no_stderr = 1;
 287        child.out = -1;
 288        if (start_command(&child)) {
 289                logerror("daemon access hook '%s' failed to start",
 290                         access_hook);
 291                goto error_return;
 292        }
 293        if (strbuf_read(&buf, child.out, 0) < 0) {
 294                logerror("failed to read from pipe to daemon access hook '%s'",
 295                         access_hook);
 296                strbuf_reset(&buf);
 297                seen_errors = 1;
 298        }
 299        if (close(child.out) < 0) {
 300                logerror("failed to close pipe to daemon access hook '%s'",
 301                         access_hook);
 302                seen_errors = 1;
 303        }
 304        if (finish_command(&child))
 305                seen_errors = 1;
 306
 307        if (!seen_errors) {
 308                strbuf_release(&buf);
 309                return 0;
 310        }
 311
 312error_return:
 313        strbuf_ltrim(&buf);
 314        if (!buf.len)
 315                strbuf_addstr(&buf, "service rejected");
 316        eol = strchr(buf.buf, '\n');
 317        if (eol)
 318                *eol = '\0';
 319        errno = EACCES;
 320        daemon_error(dir, buf.buf);
 321        strbuf_release(&buf);
 322        return -1;
 323}
 324
 325static int run_service(char *dir, struct daemon_service *service)
 326{
 327        const char *path;
 328        int enabled = service->enabled;
 329
 330        loginfo("Request %s for '%s'", service->name, dir);
 331
 332        if (!enabled && !service->overridable) {
 333                logerror("'%s': service not enabled.", service->name);
 334                errno = EACCES;
 335                return daemon_error(dir, "service not enabled");
 336        }
 337
 338        if (!(path = path_ok(dir)))
 339                return daemon_error(dir, "no such repository");
 340
 341        /*
 342         * Security on the cheap.
 343         *
 344         * We want a readable HEAD, usable "objects" directory, and
 345         * a "git-daemon-export-ok" flag that says that the other side
 346         * is ok with us doing this.
 347         *
 348         * path_ok() uses enter_repo() and does whitelist checking.
 349         * We only need to make sure the repository is exported.
 350         */
 351
 352        if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 353                logerror("'%s': repository not exported.", path);
 354                errno = EACCES;
 355                return daemon_error(dir, "repository not exported");
 356        }
 357
 358        if (service->overridable) {
 359                service_looking_at = service;
 360                service_enabled = -1;
 361                git_config(git_daemon_config, NULL);
 362                if (0 <= service_enabled)
 363                        enabled = service_enabled;
 364        }
 365        if (!enabled) {
 366                logerror("'%s': service not enabled for '%s'",
 367                         service->name, path);
 368                errno = EACCES;
 369                return daemon_error(dir, "service not enabled");
 370        }
 371
 372        /*
 373         * Optionally, a hook can choose to deny access to the
 374         * repository depending on the phase of the moon.
 375         */
 376        if (access_hook && run_access_hook(service, dir, path))
 377                return -1;
 378
 379        /*
 380         * We'll ignore SIGTERM from now on, we have a
 381         * good client.
 382         */
 383        signal(SIGTERM, SIG_IGN);
 384
 385        return service->fn();
 386}
 387
 388static void copy_to_log(int fd)
 389{
 390        struct strbuf line = STRBUF_INIT;
 391        FILE *fp;
 392
 393        fp = fdopen(fd, "r");
 394        if (fp == NULL) {
 395                logerror("fdopen of error channel failed");
 396                close(fd);
 397                return;
 398        }
 399
 400        while (strbuf_getline(&line, fp, '\n') != EOF) {
 401                logerror("%s", line.buf);
 402                strbuf_setlen(&line, 0);
 403        }
 404
 405        strbuf_release(&line);
 406        fclose(fp);
 407}
 408
 409static int run_service_command(const char **argv)
 410{
 411        struct child_process cld;
 412
 413        memset(&cld, 0, sizeof(cld));
 414        cld.argv = argv;
 415        cld.git_cmd = 1;
 416        cld.err = -1;
 417        if (start_command(&cld))
 418                return -1;
 419
 420        close(0);
 421        close(1);
 422
 423        copy_to_log(cld.err);
 424
 425        return finish_command(&cld);
 426}
 427
 428static int upload_pack(void)
 429{
 430        /* Timeout as string */
 431        char timeout_buf[64];
 432        const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
 433
 434        argv[2] = timeout_buf;
 435
 436        snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 437        return run_service_command(argv);
 438}
 439
 440static int upload_archive(void)
 441{
 442        static const char *argv[] = { "upload-archive", ".", NULL };
 443        return run_service_command(argv);
 444}
 445
 446static int receive_pack(void)
 447{
 448        static const char *argv[] = { "receive-pack", ".", NULL };
 449        return run_service_command(argv);
 450}
 451
 452static struct daemon_service daemon_service[] = {
 453        { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 454        { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 455        { "receive-pack", "receivepack", receive_pack, 0, 1 },
 456};
 457
 458static void enable_service(const char *name, int ena)
 459{
 460        int i;
 461        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 462                if (!strcmp(daemon_service[i].name, name)) {
 463                        daemon_service[i].enabled = ena;
 464                        return;
 465                }
 466        }
 467        die("No such service %s", name);
 468}
 469
 470static void make_service_overridable(const char *name, int ena)
 471{
 472        int i;
 473        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 474                if (!strcmp(daemon_service[i].name, name)) {
 475                        daemon_service[i].overridable = ena;
 476                        return;
 477                }
 478        }
 479        die("No such service %s", name);
 480}
 481
 482static char *xstrdup_tolower(const char *str)
 483{
 484        char *p, *dup = xstrdup(str);
 485        for (p = dup; *p; p++)
 486                *p = tolower(*p);
 487        return dup;
 488}
 489
 490static void parse_host_and_port(char *hostport, char **host,
 491        char **port)
 492{
 493        if (*hostport == '[') {
 494                char *end;
 495
 496                end = strchr(hostport, ']');
 497                if (!end)
 498                        die("Invalid request ('[' without ']')");
 499                *end = '\0';
 500                *host = hostport + 1;
 501                if (!end[1])
 502                        *port = NULL;
 503                else if (end[1] == ':')
 504                        *port = end + 2;
 505                else
 506                        die("Garbage after end of host part");
 507        } else {
 508                *host = hostport;
 509                *port = strrchr(hostport, ':');
 510                if (*port) {
 511                        **port = '\0';
 512                        ++*port;
 513                }
 514        }
 515}
 516
 517/*
 518 * Read the host as supplied by the client connection.
 519 */
 520static void parse_host_arg(char *extra_args, int buflen)
 521{
 522        char *val;
 523        int vallen;
 524        char *end = extra_args + buflen;
 525
 526        if (extra_args < end && *extra_args) {
 527                saw_extended_args = 1;
 528                if (strncasecmp("host=", extra_args, 5) == 0) {
 529                        val = extra_args + 5;
 530                        vallen = strlen(val) + 1;
 531                        if (*val) {
 532                                /* Split <host>:<port> at colon. */
 533                                char *host;
 534                                char *port;
 535                                parse_host_and_port(val, &host, &port);
 536                                if (port) {
 537                                        free(tcp_port);
 538                                        tcp_port = xstrdup(port);
 539                                }
 540                                free(hostname);
 541                                hostname = xstrdup_tolower(host);
 542                        }
 543
 544                        /* On to the next one */
 545                        extra_args = val + vallen;
 546                }
 547                if (extra_args < end && *extra_args)
 548                        die("Invalid request");
 549        }
 550
 551        /*
 552         * Locate canonical hostname and its IP address.
 553         */
 554        if (hostname) {
 555#ifndef NO_IPV6
 556                struct addrinfo hints;
 557                struct addrinfo *ai;
 558                int gai;
 559                static char addrbuf[HOST_NAME_MAX + 1];
 560
 561                memset(&hints, 0, sizeof(hints));
 562                hints.ai_flags = AI_CANONNAME;
 563
 564                gai = getaddrinfo(hostname, NULL, &hints, &ai);
 565                if (!gai) {
 566                        struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 567
 568                        inet_ntop(AF_INET, &sin_addr->sin_addr,
 569                                  addrbuf, sizeof(addrbuf));
 570                        free(ip_address);
 571                        ip_address = xstrdup(addrbuf);
 572
 573                        free(canon_hostname);
 574                        canon_hostname = xstrdup(ai->ai_canonname ?
 575                                                 ai->ai_canonname : ip_address);
 576
 577                        freeaddrinfo(ai);
 578                }
 579#else
 580                struct hostent *hent;
 581                struct sockaddr_in sa;
 582                char **ap;
 583                static char addrbuf[HOST_NAME_MAX + 1];
 584
 585                hent = gethostbyname(hostname);
 586
 587                ap = hent->h_addr_list;
 588                memset(&sa, 0, sizeof sa);
 589                sa.sin_family = hent->h_addrtype;
 590                sa.sin_port = htons(0);
 591                memcpy(&sa.sin_addr, *ap, hent->h_length);
 592
 593                inet_ntop(hent->h_addrtype, &sa.sin_addr,
 594                          addrbuf, sizeof(addrbuf));
 595
 596                free(canon_hostname);
 597                canon_hostname = xstrdup(hent->h_name);
 598                free(ip_address);
 599                ip_address = xstrdup(addrbuf);
 600#endif
 601        }
 602}
 603
 604
 605static int execute(void)
 606{
 607        static char line[1000];
 608        int pktlen, len, i;
 609        char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
 610
 611        if (addr)
 612                loginfo("Connection from %s:%s", addr, port);
 613
 614        alarm(init_timeout ? init_timeout : timeout);
 615        pktlen = packet_read_line(0, line, sizeof(line));
 616        alarm(0);
 617
 618        len = strlen(line);
 619        if (pktlen != len)
 620                loginfo("Extended attributes (%d bytes) exist <%.*s>",
 621                        (int) pktlen - len,
 622                        (int) pktlen - len, line + len + 1);
 623        if (len && line[len-1] == '\n') {
 624                line[--len] = 0;
 625                pktlen--;
 626        }
 627
 628        free(hostname);
 629        free(canon_hostname);
 630        free(ip_address);
 631        free(tcp_port);
 632        hostname = canon_hostname = ip_address = tcp_port = NULL;
 633
 634        if (len != pktlen)
 635                parse_host_arg(line + len + 1, pktlen - len - 1);
 636
 637        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 638                struct daemon_service *s = &(daemon_service[i]);
 639                int namelen = strlen(s->name);
 640                if (!prefixcmp(line, "git-") &&
 641                    !strncmp(s->name, line + 4, namelen) &&
 642                    line[namelen + 4] == ' ') {
 643                        /*
 644                         * Note: The directory here is probably context sensitive,
 645                         * and might depend on the actual service being performed.
 646                         */
 647                        return run_service(line + namelen + 5, s);
 648                }
 649        }
 650
 651        logerror("Protocol error: '%s'", line);
 652        return -1;
 653}
 654
 655static int addrcmp(const struct sockaddr_storage *s1,
 656    const struct sockaddr_storage *s2)
 657{
 658        const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 659        const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 660
 661        if (sa1->sa_family != sa2->sa_family)
 662                return sa1->sa_family - sa2->sa_family;
 663        if (sa1->sa_family == AF_INET)
 664                return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 665                    &((struct sockaddr_in *)s2)->sin_addr,
 666                    sizeof(struct in_addr));
 667#ifndef NO_IPV6
 668        if (sa1->sa_family == AF_INET6)
 669                return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 670                    &((struct sockaddr_in6 *)s2)->sin6_addr,
 671                    sizeof(struct in6_addr));
 672#endif
 673        return 0;
 674}
 675
 676static int max_connections = 32;
 677
 678static unsigned int live_children;
 679
 680static struct child {
 681        struct child *next;
 682        struct child_process cld;
 683        struct sockaddr_storage address;
 684} *firstborn;
 685
 686static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
 687{
 688        struct child *newborn, **cradle;
 689
 690        newborn = xcalloc(1, sizeof(*newborn));
 691        live_children++;
 692        memcpy(&newborn->cld, cld, sizeof(*cld));
 693        memcpy(&newborn->address, addr, addrlen);
 694        for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 695                if (!addrcmp(&(*cradle)->address, &newborn->address))
 696                        break;
 697        newborn->next = *cradle;
 698        *cradle = newborn;
 699}
 700
 701/*
 702 * This gets called if the number of connections grows
 703 * past "max_connections".
 704 *
 705 * We kill the newest connection from a duplicate IP.
 706 */
 707static void kill_some_child(void)
 708{
 709        const struct child *blanket, *next;
 710
 711        if (!(blanket = firstborn))
 712                return;
 713
 714        for (; (next = blanket->next); blanket = next)
 715                if (!addrcmp(&blanket->address, &next->address)) {
 716                        kill(blanket->cld.pid, SIGTERM);
 717                        break;
 718                }
 719}
 720
 721static void check_dead_children(void)
 722{
 723        int status;
 724        pid_t pid;
 725
 726        struct child **cradle, *blanket;
 727        for (cradle = &firstborn; (blanket = *cradle);)
 728                if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
 729                        const char *dead = "";
 730                        if (status)
 731                                dead = " (with error)";
 732                        loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 733
 734                        /* remove the child */
 735                        *cradle = blanket->next;
 736                        live_children--;
 737                        free(blanket);
 738                } else
 739                        cradle = &blanket->next;
 740}
 741
 742static char **cld_argv;
 743static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 744{
 745        struct child_process cld = { NULL };
 746        char addrbuf[300] = "REMOTE_ADDR=", portbuf[300];
 747        char *env[] = { addrbuf, portbuf, NULL };
 748
 749        if (max_connections && live_children >= max_connections) {
 750                kill_some_child();
 751                sleep(1);  /* give it some time to die */
 752                check_dead_children();
 753                if (live_children >= max_connections) {
 754                        close(incoming);
 755                        logerror("Too many children, dropping connection");
 756                        return;
 757                }
 758        }
 759
 760        if (addr->sa_family == AF_INET) {
 761                struct sockaddr_in *sin_addr = (void *) addr;
 762                inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf + 12,
 763                    sizeof(addrbuf) - 12);
 764                snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 765                    ntohs(sin_addr->sin_port));
 766#ifndef NO_IPV6
 767        } else if (addr && addr->sa_family == AF_INET6) {
 768                struct sockaddr_in6 *sin6_addr = (void *) addr;
 769
 770                char *buf = addrbuf + 12;
 771                *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 772                inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf,
 773                    sizeof(addrbuf) - 13);
 774                strcat(buf, "]");
 775
 776                snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 777                    ntohs(sin6_addr->sin6_port));
 778#endif
 779        }
 780
 781        cld.env = (const char **)env;
 782        cld.argv = (const char **)cld_argv;
 783        cld.in = incoming;
 784        cld.out = dup(incoming);
 785
 786        if (start_command(&cld))
 787                logerror("unable to fork");
 788        else
 789                add_child(&cld, addr, addrlen);
 790        close(incoming);
 791}
 792
 793static void child_handler(int signo)
 794{
 795        /*
 796         * Otherwise empty handler because systemcalls will get interrupted
 797         * upon signal receipt
 798         * SysV needs the handler to be rearmed
 799         */
 800        signal(SIGCHLD, child_handler);
 801}
 802
 803static int set_reuse_addr(int sockfd)
 804{
 805        int on = 1;
 806
 807        if (!reuseaddr)
 808                return 0;
 809        return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 810                          &on, sizeof(on));
 811}
 812
 813struct socketlist {
 814        int *list;
 815        size_t nr;
 816        size_t alloc;
 817};
 818
 819static const char *ip2str(int family, struct sockaddr *sin, socklen_t len)
 820{
 821#ifdef NO_IPV6
 822        static char ip[INET_ADDRSTRLEN];
 823#else
 824        static char ip[INET6_ADDRSTRLEN];
 825#endif
 826
 827        switch (family) {
 828#ifndef NO_IPV6
 829        case AF_INET6:
 830                inet_ntop(family, &((struct sockaddr_in6*)sin)->sin6_addr, ip, len);
 831                break;
 832#endif
 833        case AF_INET:
 834                inet_ntop(family, &((struct sockaddr_in*)sin)->sin_addr, ip, len);
 835                break;
 836        default:
 837                strcpy(ip, "<unknown>");
 838        }
 839        return ip;
 840}
 841
 842#ifndef NO_IPV6
 843
 844static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 845{
 846        int socknum = 0;
 847        int maxfd = -1;
 848        char pbuf[NI_MAXSERV];
 849        struct addrinfo hints, *ai0, *ai;
 850        int gai;
 851        long flags;
 852
 853        sprintf(pbuf, "%d", listen_port);
 854        memset(&hints, 0, sizeof(hints));
 855        hints.ai_family = AF_UNSPEC;
 856        hints.ai_socktype = SOCK_STREAM;
 857        hints.ai_protocol = IPPROTO_TCP;
 858        hints.ai_flags = AI_PASSIVE;
 859
 860        gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 861        if (gai) {
 862                logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
 863                return 0;
 864        }
 865
 866        for (ai = ai0; ai; ai = ai->ai_next) {
 867                int sockfd;
 868
 869                sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 870                if (sockfd < 0)
 871                        continue;
 872                if (sockfd >= FD_SETSIZE) {
 873                        logerror("Socket descriptor too large");
 874                        close(sockfd);
 875                        continue;
 876                }
 877
 878#ifdef IPV6_V6ONLY
 879                if (ai->ai_family == AF_INET6) {
 880                        int on = 1;
 881                        setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 882                                   &on, sizeof(on));
 883                        /* Note: error is not fatal */
 884                }
 885#endif
 886
 887                if (set_reuse_addr(sockfd)) {
 888                        logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 889                        close(sockfd);
 890                        continue;
 891                }
 892
 893                if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 894                        logerror("Could not bind to %s: %s",
 895                                 ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 896                                 strerror(errno));
 897                        close(sockfd);
 898                        continue;       /* not fatal */
 899                }
 900                if (listen(sockfd, 5) < 0) {
 901                        logerror("Could not listen to %s: %s",
 902                                 ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 903                                 strerror(errno));
 904                        close(sockfd);
 905                        continue;       /* not fatal */
 906                }
 907
 908                flags = fcntl(sockfd, F_GETFD, 0);
 909                if (flags >= 0)
 910                        fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 911
 912                ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 913                socklist->list[socklist->nr++] = sockfd;
 914                socknum++;
 915
 916                if (maxfd < sockfd)
 917                        maxfd = sockfd;
 918        }
 919
 920        freeaddrinfo(ai0);
 921
 922        return socknum;
 923}
 924
 925#else /* NO_IPV6 */
 926
 927static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 928{
 929        struct sockaddr_in sin;
 930        int sockfd;
 931        long flags;
 932
 933        memset(&sin, 0, sizeof sin);
 934        sin.sin_family = AF_INET;
 935        sin.sin_port = htons(listen_port);
 936
 937        if (listen_addr) {
 938                /* Well, host better be an IP address here. */
 939                if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 940                        return 0;
 941        } else {
 942                sin.sin_addr.s_addr = htonl(INADDR_ANY);
 943        }
 944
 945        sockfd = socket(AF_INET, SOCK_STREAM, 0);
 946        if (sockfd < 0)
 947                return 0;
 948
 949        if (set_reuse_addr(sockfd)) {
 950                logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 951                close(sockfd);
 952                return 0;
 953        }
 954
 955        if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 956                logerror("Could not listen to %s: %s",
 957                         ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
 958                         strerror(errno));
 959                close(sockfd);
 960                return 0;
 961        }
 962
 963        if (listen(sockfd, 5) < 0) {
 964                logerror("Could not listen to %s: %s",
 965                         ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
 966                         strerror(errno));
 967                close(sockfd);
 968                return 0;
 969        }
 970
 971        flags = fcntl(sockfd, F_GETFD, 0);
 972        if (flags >= 0)
 973                fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 974
 975        ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 976        socklist->list[socklist->nr++] = sockfd;
 977        return 1;
 978}
 979
 980#endif
 981
 982static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
 983{
 984        if (!listen_addr->nr)
 985                setup_named_sock(NULL, listen_port, socklist);
 986        else {
 987                int i, socknum;
 988                for (i = 0; i < listen_addr->nr; i++) {
 989                        socknum = setup_named_sock(listen_addr->items[i].string,
 990                                                   listen_port, socklist);
 991
 992                        if (socknum == 0)
 993                                logerror("unable to allocate any listen sockets for host %s on port %u",
 994                                         listen_addr->items[i].string, listen_port);
 995                }
 996        }
 997}
 998
 999static int service_loop(struct socketlist *socklist)
1000{
1001        struct pollfd *pfd;
1002        int i;
1003
1004        pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
1005
1006        for (i = 0; i < socklist->nr; i++) {
1007                pfd[i].fd = socklist->list[i];
1008                pfd[i].events = POLLIN;
1009        }
1010
1011        signal(SIGCHLD, child_handler);
1012
1013        for (;;) {
1014                int i;
1015
1016                check_dead_children();
1017
1018                if (poll(pfd, socklist->nr, -1) < 0) {
1019                        if (errno != EINTR) {
1020                                logerror("Poll failed, resuming: %s",
1021                                      strerror(errno));
1022                                sleep(1);
1023                        }
1024                        continue;
1025                }
1026
1027                for (i = 0; i < socklist->nr; i++) {
1028                        if (pfd[i].revents & POLLIN) {
1029                                union {
1030                                        struct sockaddr sa;
1031                                        struct sockaddr_in sai;
1032#ifndef NO_IPV6
1033                                        struct sockaddr_in6 sai6;
1034#endif
1035                                } ss;
1036                                socklen_t sslen = sizeof(ss);
1037                                int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
1038                                if (incoming < 0) {
1039                                        switch (errno) {
1040                                        case EAGAIN:
1041                                        case EINTR:
1042                                        case ECONNABORTED:
1043                                                continue;
1044                                        default:
1045                                                die_errno("accept returned");
1046                                        }
1047                                }
1048                                handle(incoming, &ss.sa, sslen);
1049                        }
1050                }
1051        }
1052}
1053
1054/* if any standard file descriptor is missing open it to /dev/null */
1055static void sanitize_stdfds(void)
1056{
1057        int fd = open("/dev/null", O_RDWR, 0);
1058        while (fd != -1 && fd < 2)
1059                fd = dup(fd);
1060        if (fd == -1)
1061                die_errno("open /dev/null or dup failed");
1062        if (fd > 2)
1063                close(fd);
1064}
1065
1066#ifdef NO_POSIX_GOODIES
1067
1068struct credentials;
1069
1070static void drop_privileges(struct credentials *cred)
1071{
1072        /* nothing */
1073}
1074
1075static void daemonize(void)
1076{
1077        die("--detach not supported on this platform");
1078}
1079
1080static struct credentials *prepare_credentials(const char *user_name,
1081    const char *group_name)
1082{
1083        die("--user not supported on this platform");
1084}
1085
1086#else
1087
1088struct credentials {
1089        struct passwd *pass;
1090        gid_t gid;
1091};
1092
1093static void drop_privileges(struct credentials *cred)
1094{
1095        if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
1096            setgid (cred->gid) || setuid(cred->pass->pw_uid)))
1097                die("cannot drop privileges");
1098}
1099
1100static struct credentials *prepare_credentials(const char *user_name,
1101    const char *group_name)
1102{
1103        static struct credentials c;
1104
1105        c.pass = getpwnam(user_name);
1106        if (!c.pass)
1107                die("user not found - %s", user_name);
1108
1109        if (!group_name)
1110                c.gid = c.pass->pw_gid;
1111        else {
1112                struct group *group = getgrnam(group_name);
1113                if (!group)
1114                        die("group not found - %s", group_name);
1115
1116                c.gid = group->gr_gid;
1117        }
1118
1119        return &c;
1120}
1121
1122static void daemonize(void)
1123{
1124        switch (fork()) {
1125                case 0:
1126                        break;
1127                case -1:
1128                        die_errno("fork failed");
1129                default:
1130                        exit(0);
1131        }
1132        if (setsid() == -1)
1133                die_errno("setsid failed");
1134        close(0);
1135        close(1);
1136        close(2);
1137        sanitize_stdfds();
1138}
1139#endif
1140
1141static void store_pid(const char *path)
1142{
1143        FILE *f = fopen(path, "w");
1144        if (!f)
1145                die_errno("cannot open pid file '%s'", path);
1146        if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
1147                die_errno("failed to write pid file '%s'", path);
1148}
1149
1150static int serve(struct string_list *listen_addr, int listen_port,
1151    struct credentials *cred)
1152{
1153        struct socketlist socklist = { NULL, 0, 0 };
1154
1155        socksetup(listen_addr, listen_port, &socklist);
1156        if (socklist.nr == 0)
1157                die("unable to allocate any listen sockets on port %u",
1158                    listen_port);
1159
1160        drop_privileges(cred);
1161
1162        loginfo("Ready to rumble");
1163
1164        return service_loop(&socklist);
1165}
1166
1167int main(int argc, char **argv)
1168{
1169        int listen_port = 0;
1170        struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1171        int serve_mode = 0, inetd_mode = 0;
1172        const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1173        int detach = 0;
1174        struct credentials *cred = NULL;
1175        int i;
1176
1177        git_setup_gettext();
1178
1179        git_extract_argv0_path(argv[0]);
1180
1181        for (i = 1; i < argc; i++) {
1182                char *arg = argv[i];
1183
1184                if (!prefixcmp(arg, "--listen=")) {
1185                        string_list_append(&listen_addr, xstrdup_tolower(arg + 9));
1186                        continue;
1187                }
1188                if (!prefixcmp(arg, "--port=")) {
1189                        char *end;
1190                        unsigned long n;
1191                        n = strtoul(arg+7, &end, 0);
1192                        if (arg[7] && !*end) {
1193                                listen_port = n;
1194                                continue;
1195                        }
1196                }
1197                if (!strcmp(arg, "--serve")) {
1198                        serve_mode = 1;
1199                        continue;
1200                }
1201                if (!strcmp(arg, "--inetd")) {
1202                        inetd_mode = 1;
1203                        log_syslog = 1;
1204                        continue;
1205                }
1206                if (!strcmp(arg, "--verbose")) {
1207                        verbose = 1;
1208                        continue;
1209                }
1210                if (!strcmp(arg, "--syslog")) {
1211                        log_syslog = 1;
1212                        continue;
1213                }
1214                if (!strcmp(arg, "--export-all")) {
1215                        export_all_trees = 1;
1216                        continue;
1217                }
1218                if (!prefixcmp(arg, "--access-hook=")) {
1219                        access_hook = arg + 14;
1220                        continue;
1221                }
1222                if (!prefixcmp(arg, "--timeout=")) {
1223                        timeout = atoi(arg+10);
1224                        continue;
1225                }
1226                if (!prefixcmp(arg, "--init-timeout=")) {
1227                        init_timeout = atoi(arg+15);
1228                        continue;
1229                }
1230                if (!prefixcmp(arg, "--max-connections=")) {
1231                        max_connections = atoi(arg+18);
1232                        if (max_connections < 0)
1233                                max_connections = 0;            /* unlimited */
1234                        continue;
1235                }
1236                if (!strcmp(arg, "--strict-paths")) {
1237                        strict_paths = 1;
1238                        continue;
1239                }
1240                if (!prefixcmp(arg, "--base-path=")) {
1241                        base_path = arg+12;
1242                        continue;
1243                }
1244                if (!strcmp(arg, "--base-path-relaxed")) {
1245                        base_path_relaxed = 1;
1246                        continue;
1247                }
1248                if (!prefixcmp(arg, "--interpolated-path=")) {
1249                        interpolated_path = arg+20;
1250                        continue;
1251                }
1252                if (!strcmp(arg, "--reuseaddr")) {
1253                        reuseaddr = 1;
1254                        continue;
1255                }
1256                if (!strcmp(arg, "--user-path")) {
1257                        user_path = "";
1258                        continue;
1259                }
1260                if (!prefixcmp(arg, "--user-path=")) {
1261                        user_path = arg + 12;
1262                        continue;
1263                }
1264                if (!prefixcmp(arg, "--pid-file=")) {
1265                        pid_file = arg + 11;
1266                        continue;
1267                }
1268                if (!strcmp(arg, "--detach")) {
1269                        detach = 1;
1270                        log_syslog = 1;
1271                        continue;
1272                }
1273                if (!prefixcmp(arg, "--user=")) {
1274                        user_name = arg + 7;
1275                        continue;
1276                }
1277                if (!prefixcmp(arg, "--group=")) {
1278                        group_name = arg + 8;
1279                        continue;
1280                }
1281                if (!prefixcmp(arg, "--enable=")) {
1282                        enable_service(arg + 9, 1);
1283                        continue;
1284                }
1285                if (!prefixcmp(arg, "--disable=")) {
1286                        enable_service(arg + 10, 0);
1287                        continue;
1288                }
1289                if (!prefixcmp(arg, "--allow-override=")) {
1290                        make_service_overridable(arg + 17, 1);
1291                        continue;
1292                }
1293                if (!prefixcmp(arg, "--forbid-override=")) {
1294                        make_service_overridable(arg + 18, 0);
1295                        continue;
1296                }
1297                if (!prefixcmp(arg, "--informative-errors")) {
1298                        informative_errors = 1;
1299                        continue;
1300                }
1301                if (!prefixcmp(arg, "--no-informative-errors")) {
1302                        informative_errors = 0;
1303                        continue;
1304                }
1305                if (!strcmp(arg, "--")) {
1306                        ok_paths = &argv[i+1];
1307                        break;
1308                } else if (arg[0] != '-') {
1309                        ok_paths = &argv[i];
1310                        break;
1311                }
1312
1313                usage(daemon_usage);
1314        }
1315
1316        if (log_syslog) {
1317                openlog("git-daemon", LOG_PID, LOG_DAEMON);
1318                set_die_routine(daemon_die);
1319        } else
1320                /* avoid splitting a message in the middle */
1321                setvbuf(stderr, NULL, _IOFBF, 4096);
1322
1323        if (inetd_mode && (detach || group_name || user_name))
1324                die("--detach, --user and --group are incompatible with --inetd");
1325
1326        if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1327                die("--listen= and --port= are incompatible with --inetd");
1328        else if (listen_port == 0)
1329                listen_port = DEFAULT_GIT_PORT;
1330
1331        if (group_name && !user_name)
1332                die("--group supplied without --user");
1333
1334        if (user_name)
1335                cred = prepare_credentials(user_name, group_name);
1336
1337        if (strict_paths && (!ok_paths || !*ok_paths))
1338                die("option --strict-paths requires a whitelist");
1339
1340        if (base_path && !is_directory(base_path))
1341                die("base-path '%s' does not exist or is not a directory",
1342                    base_path);
1343
1344        if (inetd_mode) {
1345                if (!freopen("/dev/null", "w", stderr))
1346                        die_errno("failed to redirect stderr to /dev/null");
1347        }
1348
1349        if (inetd_mode || serve_mode)
1350                return execute();
1351
1352        if (detach)
1353                daemonize();
1354        else
1355                sanitize_stdfds();
1356
1357        if (pid_file)
1358                store_pid(pid_file);
1359
1360        /* prepare argv for serving-processes */
1361        cld_argv = xmalloc(sizeof (char *) * (argc + 2));
1362        cld_argv[0] = argv[0];  /* git-daemon */
1363        cld_argv[1] = "--serve";
1364        for (i = 1; i < argc; ++i)
1365                cld_argv[i+1] = argv[i];
1366        cld_argv[argc+1] = NULL;
1367
1368        return serve(&listen_addr, listen_port, cred);
1369}