daemon.con commit Fix multi-glob assertion in git-svn (b47ddef)
   1#include "cache.h"
   2#include "pkt-line.h"
   3#include "exec_cmd.h"
   4#include "interpolate.h"
   5
   6#include <syslog.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
  16static int log_syslog;
  17static int verbose;
  18static int reuseaddr;
  19static int child_handler_pipe[2];
  20
  21static const char daemon_usage[] =
  22"git daemon [--verbose] [--syslog] [--export-all]\n"
  23"           [--timeout=n] [--init-timeout=n] [--strict-paths]\n"
  24"           [--base-path=path] [--base-path-relaxed]\n"
  25"           [--user-path | --user-path=path]\n"
  26"           [--interpolated-path=path]\n"
  27"           [--reuseaddr] [--detach] [--pid-file=file]\n"
  28"           [--[enable|disable|allow-override|forbid-override]=service]\n"
  29"           [--inetd | [--listen=host_or_ipaddr] [--port=n]\n"
  30"                      [--user=user [--group=group]]\n"
  31"           [directory...]";
  32
  33/* List of acceptable pathname prefixes */
  34static char **ok_paths;
  35static int strict_paths;
  36
  37/* If this is set, git-daemon-export-ok is not required */
  38static int export_all_trees;
  39
  40/* Take all paths relative to this one if non-NULL */
  41static char *base_path;
  42static char *interpolated_path;
  43static int base_path_relaxed;
  44
  45/* Flag indicating client sent extra args. */
  46static int saw_extended_args;
  47
  48/* If defined, ~user notation is allowed and the string is inserted
  49 * after ~user/.  E.g. a request to git://host/~alice/frotz would
  50 * go to /home/alice/pub_git/frotz with --user-path=pub_git.
  51 */
  52static const char *user_path;
  53
  54/* Timeout, and initial timeout */
  55static unsigned int timeout;
  56static unsigned int init_timeout;
  57
  58/*
  59 * Static table for now.  Ugh.
  60 * Feel free to make dynamic as needed.
  61 */
  62#define INTERP_SLOT_HOST        (0)
  63#define INTERP_SLOT_CANON_HOST  (1)
  64#define INTERP_SLOT_IP          (2)
  65#define INTERP_SLOT_PORT        (3)
  66#define INTERP_SLOT_DIR         (4)
  67#define INTERP_SLOT_PERCENT     (5)
  68
  69static struct interp interp_table[] = {
  70        { "%H", 0},
  71        { "%CH", 0},
  72        { "%IP", 0},
  73        { "%P", 0},
  74        { "%D", 0},
  75        { "%%", 0},
  76};
  77
  78
  79static void logreport(int priority, const char *err, va_list params)
  80{
  81        /* We should do a single write so that it is atomic and output
  82         * of several processes do not get intermingled. */
  83        char buf[1024];
  84        int buflen;
  85        int maxlen, msglen;
  86
  87        /* sizeof(buf) should be big enough for "[pid] \n" */
  88        buflen = snprintf(buf, sizeof(buf), "[%ld] ", (long) getpid());
  89
  90        maxlen = sizeof(buf) - buflen - 1; /* -1 for our own LF */
  91        msglen = vsnprintf(buf + buflen, maxlen, err, params);
  92
  93        if (log_syslog) {
  94                syslog(priority, "%s", buf);
  95                return;
  96        }
  97
  98        /* maxlen counted our own LF but also counts space given to
  99         * vsnprintf for the terminating NUL.  We want to make sure that
 100         * we have space for our own LF and NUL after the "meat" of the
 101         * message, so truncate it at maxlen - 1.
 102         */
 103        if (msglen > maxlen - 1)
 104                msglen = maxlen - 1;
 105        else if (msglen < 0)
 106                msglen = 0; /* Protect against weird return values. */
 107        buflen += msglen;
 108
 109        buf[buflen++] = '\n';
 110        buf[buflen] = '\0';
 111
 112        write_in_full(2, buf, buflen);
 113}
 114
 115static void logerror(const char *err, ...)
 116{
 117        va_list params;
 118        va_start(params, err);
 119        logreport(LOG_ERR, err, params);
 120        va_end(params);
 121}
 122
 123static void loginfo(const char *err, ...)
 124{
 125        va_list params;
 126        if (!verbose)
 127                return;
 128        va_start(params, err);
 129        logreport(LOG_INFO, err, params);
 130        va_end(params);
 131}
 132
 133static void NORETURN daemon_die(const char *err, va_list params)
 134{
 135        logreport(LOG_ERR, err, params);
 136        exit(1);
 137}
 138
 139static int avoid_alias(char *p)
 140{
 141        int sl, ndot;
 142
 143        /*
 144         * This resurrects the belts and suspenders paranoia check by HPA
 145         * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
 146         * does not do getcwd() based path canonicalizations.
 147         *
 148         * sl becomes true immediately after seeing '/' and continues to
 149         * be true as long as dots continue after that without intervening
 150         * non-dot character.
 151         */
 152        if (!p || (*p != '/' && *p != '~'))
 153                return -1;
 154        sl = 1; ndot = 0;
 155        p++;
 156
 157        while (1) {
 158                char ch = *p++;
 159                if (sl) {
 160                        if (ch == '.')
 161                                ndot++;
 162                        else if (ch == '/') {
 163                                if (ndot < 3)
 164                                        /* reject //, /./ and /../ */
 165                                        return -1;
 166                                ndot = 0;
 167                        }
 168                        else if (ch == 0) {
 169                                if (0 < ndot && ndot < 3)
 170                                        /* reject /.$ and /..$ */
 171                                        return -1;
 172                                return 0;
 173                        }
 174                        else
 175                                sl = ndot = 0;
 176                }
 177                else if (ch == 0)
 178                        return 0;
 179                else if (ch == '/') {
 180                        sl = 1;
 181                        ndot = 0;
 182                }
 183        }
 184}
 185
 186static char *path_ok(struct interp *itable)
 187{
 188        static char rpath[PATH_MAX];
 189        static char interp_path[PATH_MAX];
 190        int retried_path = 0;
 191        char *path;
 192        char *dir;
 193
 194        dir = itable[INTERP_SLOT_DIR].value;
 195
 196        if (avoid_alias(dir)) {
 197                logerror("'%s': aliased", dir);
 198                return NULL;
 199        }
 200
 201        if (*dir == '~') {
 202                if (!user_path) {
 203                        logerror("'%s': User-path not allowed", dir);
 204                        return NULL;
 205                }
 206                if (*user_path) {
 207                        /* Got either "~alice" or "~alice/foo";
 208                         * rewrite them to "~alice/%s" or
 209                         * "~alice/%s/foo".
 210                         */
 211                        int namlen, restlen = strlen(dir);
 212                        char *slash = strchr(dir, '/');
 213                        if (!slash)
 214                                slash = dir + restlen;
 215                        namlen = slash - dir;
 216                        restlen -= namlen;
 217                        loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
 218                        snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
 219                                 namlen, dir, user_path, restlen, slash);
 220                        dir = rpath;
 221                }
 222        }
 223        else if (interpolated_path && saw_extended_args) {
 224                if (*dir != '/') {
 225                        /* Allow only absolute */
 226                        logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 227                        return NULL;
 228                }
 229
 230                interpolate(interp_path, PATH_MAX, interpolated_path,
 231                            interp_table, ARRAY_SIZE(interp_table));
 232                loginfo("Interpolated dir '%s'", interp_path);
 233
 234                dir = interp_path;
 235        }
 236        else if (base_path) {
 237                if (*dir != '/') {
 238                        /* Allow only absolute */
 239                        logerror("'%s': Non-absolute path denied (base-path active)", dir);
 240                        return NULL;
 241                }
 242                snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
 243                dir = rpath;
 244        }
 245
 246        do {
 247                path = enter_repo(dir, strict_paths);
 248                if (path)
 249                        break;
 250
 251                /*
 252                 * if we fail and base_path_relaxed is enabled, try without
 253                 * prefixing the base path
 254                 */
 255                if (base_path && base_path_relaxed && !retried_path) {
 256                        dir = itable[INTERP_SLOT_DIR].value;
 257                        retried_path = 1;
 258                        continue;
 259                }
 260                break;
 261        } while (1);
 262
 263        if (!path) {
 264                logerror("'%s': unable to chdir or not a git archive", dir);
 265                return NULL;
 266        }
 267
 268        if ( ok_paths && *ok_paths ) {
 269                char **pp;
 270                int pathlen = strlen(path);
 271
 272                /* The validation is done on the paths after enter_repo
 273                 * appends optional {.git,.git/.git} and friends, but
 274                 * it does not use getcwd().  So if your /pub is
 275                 * a symlink to /mnt/pub, you can whitelist /pub and
 276                 * do not have to say /mnt/pub.
 277                 * Do not say /pub/.
 278                 */
 279                for ( pp = ok_paths ; *pp ; pp++ ) {
 280                        int len = strlen(*pp);
 281                        if (len <= pathlen &&
 282                            !memcmp(*pp, path, len) &&
 283                            (path[len] == '\0' ||
 284                             (!strict_paths && path[len] == '/')))
 285                                return path;
 286                }
 287        }
 288        else {
 289                /* be backwards compatible */
 290                if (!strict_paths)
 291                        return path;
 292        }
 293
 294        logerror("'%s': not in whitelist", path);
 295        return NULL;            /* Fallthrough. Deny by default */
 296}
 297
 298typedef int (*daemon_service_fn)(void);
 299struct daemon_service {
 300        const char *name;
 301        const char *config_name;
 302        daemon_service_fn fn;
 303        int enabled;
 304        int overridable;
 305};
 306
 307static struct daemon_service *service_looking_at;
 308static int service_enabled;
 309
 310static int git_daemon_config(const char *var, const char *value, void *cb)
 311{
 312        if (!prefixcmp(var, "daemon.") &&
 313            !strcmp(var + 7, service_looking_at->config_name)) {
 314                service_enabled = git_config_bool(var, value);
 315                return 0;
 316        }
 317
 318        /* we are not interested in parsing any other configuration here */
 319        return 0;
 320}
 321
 322static int run_service(struct interp *itable, struct daemon_service *service)
 323{
 324        const char *path;
 325        int enabled = service->enabled;
 326
 327        loginfo("Request %s for '%s'",
 328                service->name,
 329                itable[INTERP_SLOT_DIR].value);
 330
 331        if (!enabled && !service->overridable) {
 332                logerror("'%s': service not enabled.", service->name);
 333                errno = EACCES;
 334                return -1;
 335        }
 336
 337        if (!(path = path_ok(itable)))
 338                return -1;
 339
 340        /*
 341         * Security on the cheap.
 342         *
 343         * We want a readable HEAD, usable "objects" directory, and
 344         * a "git-daemon-export-ok" flag that says that the other side
 345         * is ok with us doing this.
 346         *
 347         * path_ok() uses enter_repo() and does whitelist checking.
 348         * We only need to make sure the repository is exported.
 349         */
 350
 351        if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 352                logerror("'%s': repository not exported.", path);
 353                errno = EACCES;
 354                return -1;
 355        }
 356
 357        if (service->overridable) {
 358                service_looking_at = service;
 359                service_enabled = -1;
 360                git_config(git_daemon_config, NULL);
 361                if (0 <= service_enabled)
 362                        enabled = service_enabled;
 363        }
 364        if (!enabled) {
 365                logerror("'%s': service not enabled for '%s'",
 366                         service->name, path);
 367                errno = EACCES;
 368                return -1;
 369        }
 370
 371        /*
 372         * We'll ignore SIGTERM from now on, we have a
 373         * good client.
 374         */
 375        signal(SIGTERM, SIG_IGN);
 376
 377        return service->fn();
 378}
 379
 380static int upload_pack(void)
 381{
 382        /* Timeout as string */
 383        char timeout_buf[64];
 384
 385        snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 386
 387        /* git-upload-pack only ever reads stuff, so this is safe */
 388        execl_git_cmd("upload-pack", "--strict", timeout_buf, ".", NULL);
 389        return -1;
 390}
 391
 392static int upload_archive(void)
 393{
 394        execl_git_cmd("upload-archive", ".", NULL);
 395        return -1;
 396}
 397
 398static int receive_pack(void)
 399{
 400        execl_git_cmd("receive-pack", ".", NULL);
 401        return -1;
 402}
 403
 404static struct daemon_service daemon_service[] = {
 405        { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 406        { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 407        { "receive-pack", "receivepack", receive_pack, 0, 1 },
 408};
 409
 410static void enable_service(const char *name, int ena)
 411{
 412        int i;
 413        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 414                if (!strcmp(daemon_service[i].name, name)) {
 415                        daemon_service[i].enabled = ena;
 416                        return;
 417                }
 418        }
 419        die("No such service %s", name);
 420}
 421
 422static void make_service_overridable(const char *name, int ena)
 423{
 424        int i;
 425        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 426                if (!strcmp(daemon_service[i].name, name)) {
 427                        daemon_service[i].overridable = ena;
 428                        return;
 429                }
 430        }
 431        die("No such service %s", name);
 432}
 433
 434/*
 435 * Separate the "extra args" information as supplied by the client connection.
 436 * Any resulting data is squirreled away in the given interpolation table.
 437 */
 438static void parse_extra_args(struct interp *table, char *extra_args, int buflen)
 439{
 440        char *val;
 441        int vallen;
 442        char *end = extra_args + buflen;
 443
 444        while (extra_args < end && *extra_args) {
 445                saw_extended_args = 1;
 446                if (strncasecmp("host=", extra_args, 5) == 0) {
 447                        val = extra_args + 5;
 448                        vallen = strlen(val) + 1;
 449                        if (*val) {
 450                                /* Split <host>:<port> at colon. */
 451                                char *host = val;
 452                                char *port = strrchr(host, ':');
 453                                if (port) {
 454                                        *port = 0;
 455                                        port++;
 456                                        interp_set_entry(table, INTERP_SLOT_PORT, port);
 457                                }
 458                                interp_set_entry(table, INTERP_SLOT_HOST, host);
 459                        }
 460
 461                        /* On to the next one */
 462                        extra_args = val + vallen;
 463                }
 464        }
 465}
 466
 467static void fill_in_extra_table_entries(struct interp *itable)
 468{
 469        char *hp;
 470
 471        /*
 472         * Replace literal host with lowercase-ized hostname.
 473         */
 474        hp = interp_table[INTERP_SLOT_HOST].value;
 475        if (!hp)
 476                return;
 477        for ( ; *hp; hp++)
 478                *hp = tolower(*hp);
 479
 480        /*
 481         * Locate canonical hostname and its IP address.
 482         */
 483#ifndef NO_IPV6
 484        {
 485                struct addrinfo hints;
 486                struct addrinfo *ai, *ai0;
 487                int gai;
 488                static char addrbuf[HOST_NAME_MAX + 1];
 489
 490                memset(&hints, 0, sizeof(hints));
 491                hints.ai_flags = AI_CANONNAME;
 492
 493                gai = getaddrinfo(interp_table[INTERP_SLOT_HOST].value, 0, &hints, &ai0);
 494                if (!gai) {
 495                        for (ai = ai0; ai; ai = ai->ai_next) {
 496                                struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 497
 498                                inet_ntop(AF_INET, &sin_addr->sin_addr,
 499                                          addrbuf, sizeof(addrbuf));
 500                                interp_set_entry(interp_table,
 501                                                 INTERP_SLOT_CANON_HOST, ai->ai_canonname);
 502                                interp_set_entry(interp_table,
 503                                                 INTERP_SLOT_IP, addrbuf);
 504                                break;
 505                        }
 506                        freeaddrinfo(ai0);
 507                }
 508        }
 509#else
 510        {
 511                struct hostent *hent;
 512                struct sockaddr_in sa;
 513                char **ap;
 514                static char addrbuf[HOST_NAME_MAX + 1];
 515
 516                hent = gethostbyname(interp_table[INTERP_SLOT_HOST].value);
 517
 518                ap = hent->h_addr_list;
 519                memset(&sa, 0, sizeof sa);
 520                sa.sin_family = hent->h_addrtype;
 521                sa.sin_port = htons(0);
 522                memcpy(&sa.sin_addr, *ap, hent->h_length);
 523
 524                inet_ntop(hent->h_addrtype, &sa.sin_addr,
 525                          addrbuf, sizeof(addrbuf));
 526
 527                interp_set_entry(interp_table, INTERP_SLOT_CANON_HOST, hent->h_name);
 528                interp_set_entry(interp_table, INTERP_SLOT_IP, addrbuf);
 529        }
 530#endif
 531}
 532
 533
 534static int execute(struct sockaddr *addr)
 535{
 536        static char line[1000];
 537        int pktlen, len, i;
 538
 539        if (addr) {
 540                char addrbuf[256] = "";
 541                int port = -1;
 542
 543                if (addr->sa_family == AF_INET) {
 544                        struct sockaddr_in *sin_addr = (void *) addr;
 545                        inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
 546                        port = ntohs(sin_addr->sin_port);
 547#ifndef NO_IPV6
 548                } else if (addr && addr->sa_family == AF_INET6) {
 549                        struct sockaddr_in6 *sin6_addr = (void *) addr;
 550
 551                        char *buf = addrbuf;
 552                        *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 553                        inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
 554                        strcat(buf, "]");
 555
 556                        port = ntohs(sin6_addr->sin6_port);
 557#endif
 558                }
 559                loginfo("Connection from %s:%d", addrbuf, port);
 560        }
 561
 562        alarm(init_timeout ? init_timeout : timeout);
 563        pktlen = packet_read_line(0, line, sizeof(line));
 564        alarm(0);
 565
 566        len = strlen(line);
 567        if (pktlen != len)
 568                loginfo("Extended attributes (%d bytes) exist <%.*s>",
 569                        (int) pktlen - len,
 570                        (int) pktlen - len, line + len + 1);
 571        if (len && line[len-1] == '\n') {
 572                line[--len] = 0;
 573                pktlen--;
 574        }
 575
 576        /*
 577         * Initialize the path interpolation table for this connection.
 578         */
 579        interp_clear_table(interp_table, ARRAY_SIZE(interp_table));
 580        interp_set_entry(interp_table, INTERP_SLOT_PERCENT, "%");
 581
 582        if (len != pktlen) {
 583            parse_extra_args(interp_table, line + len + 1, pktlen - len - 1);
 584            fill_in_extra_table_entries(interp_table);
 585        }
 586
 587        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 588                struct daemon_service *s = &(daemon_service[i]);
 589                int namelen = strlen(s->name);
 590                if (!prefixcmp(line, "git-") &&
 591                    !strncmp(s->name, line + 4, namelen) &&
 592                    line[namelen + 4] == ' ') {
 593                        /*
 594                         * Note: The directory here is probably context sensitive,
 595                         * and might depend on the actual service being performed.
 596                         */
 597                        interp_set_entry(interp_table,
 598                                         INTERP_SLOT_DIR, line + namelen + 5);
 599                        return run_service(interp_table, s);
 600                }
 601        }
 602
 603        logerror("Protocol error: '%s'", line);
 604        return -1;
 605}
 606
 607
 608/*
 609 * We count spawned/reaped separately, just to avoid any
 610 * races when updating them from signals. The SIGCHLD handler
 611 * will only update children_reaped, and the fork logic will
 612 * only update children_spawned.
 613 *
 614 * MAX_CHILDREN should be a power-of-two to make the modulus
 615 * operation cheap. It should also be at least twice
 616 * the maximum number of connections we will ever allow.
 617 */
 618#define MAX_CHILDREN 128
 619
 620static int max_connections = 25;
 621
 622/* These are updated by the signal handler */
 623static volatile unsigned int children_reaped;
 624static pid_t dead_child[MAX_CHILDREN];
 625
 626/* These are updated by the main loop */
 627static unsigned int children_spawned;
 628static unsigned int children_deleted;
 629
 630static struct child {
 631        pid_t pid;
 632        int addrlen;
 633        struct sockaddr_storage address;
 634} live_child[MAX_CHILDREN];
 635
 636static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen)
 637{
 638        live_child[idx].pid = pid;
 639        live_child[idx].addrlen = addrlen;
 640        memcpy(&live_child[idx].address, addr, addrlen);
 641}
 642
 643/*
 644 * Walk from "deleted" to "spawned", and remove child "pid".
 645 *
 646 * We move everything up by one, since the new "deleted" will
 647 * be one higher.
 648 */
 649static void remove_child(pid_t pid, unsigned deleted, unsigned spawned)
 650{
 651        struct child n;
 652
 653        deleted %= MAX_CHILDREN;
 654        spawned %= MAX_CHILDREN;
 655        if (live_child[deleted].pid == pid) {
 656                live_child[deleted].pid = -1;
 657                return;
 658        }
 659        n = live_child[deleted];
 660        for (;;) {
 661                struct child m;
 662                deleted = (deleted + 1) % MAX_CHILDREN;
 663                if (deleted == spawned)
 664                        die("could not find dead child %d\n", pid);
 665                m = live_child[deleted];
 666                live_child[deleted] = n;
 667                if (m.pid == pid)
 668                        return;
 669                n = m;
 670        }
 671}
 672
 673/*
 674 * This gets called if the number of connections grows
 675 * past "max_connections".
 676 *
 677 * We _should_ start off by searching for connections
 678 * from the same IP, and if there is some address wth
 679 * multiple connections, we should kill that first.
 680 *
 681 * As it is, we just "randomly" kill 25% of the connections,
 682 * and our pseudo-random generator sucks too. I have no
 683 * shame.
 684 *
 685 * Really, this is just a place-holder for a _real_ algorithm.
 686 */
 687static void kill_some_children(int signo, unsigned start, unsigned stop)
 688{
 689        start %= MAX_CHILDREN;
 690        stop %= MAX_CHILDREN;
 691        while (start != stop) {
 692                if (!(start & 3))
 693                        kill(live_child[start].pid, signo);
 694                start = (start + 1) % MAX_CHILDREN;
 695        }
 696}
 697
 698static void check_dead_children(void)
 699{
 700        unsigned spawned, reaped, deleted;
 701
 702        spawned = children_spawned;
 703        reaped = children_reaped;
 704        deleted = children_deleted;
 705
 706        while (deleted < reaped) {
 707                pid_t pid = dead_child[deleted % MAX_CHILDREN];
 708                const char *dead = pid < 0 ? " (with error)" : "";
 709
 710                if (pid < 0)
 711                        pid = -pid;
 712
 713                /* XXX: Custom logging, since we don't wanna getpid() */
 714                if (verbose) {
 715                        if (log_syslog)
 716                                syslog(LOG_INFO, "[%d] Disconnected%s",
 717                                                pid, dead);
 718                        else
 719                                fprintf(stderr, "[%d] Disconnected%s\n",
 720                                                pid, dead);
 721                }
 722                remove_child(pid, deleted, spawned);
 723                deleted++;
 724        }
 725        children_deleted = deleted;
 726}
 727
 728static void check_max_connections(void)
 729{
 730        for (;;) {
 731                int active;
 732                unsigned spawned, deleted;
 733
 734                check_dead_children();
 735
 736                spawned = children_spawned;
 737                deleted = children_deleted;
 738
 739                active = spawned - deleted;
 740                if (active <= max_connections)
 741                        break;
 742
 743                /* Kill some unstarted connections with SIGTERM */
 744                kill_some_children(SIGTERM, deleted, spawned);
 745                if (active <= max_connections << 1)
 746                        break;
 747
 748                /* If the SIGTERM thing isn't helping use SIGKILL */
 749                kill_some_children(SIGKILL, deleted, spawned);
 750                sleep(1);
 751        }
 752}
 753
 754static void handle(int incoming, struct sockaddr *addr, int addrlen)
 755{
 756        pid_t pid = fork();
 757
 758        if (pid) {
 759                unsigned idx;
 760
 761                close(incoming);
 762                if (pid < 0)
 763                        return;
 764
 765                idx = children_spawned % MAX_CHILDREN;
 766                children_spawned++;
 767                add_child(idx, pid, addr, addrlen);
 768
 769                check_max_connections();
 770                return;
 771        }
 772
 773        dup2(incoming, 0);
 774        dup2(incoming, 1);
 775        close(incoming);
 776
 777        exit(execute(addr));
 778}
 779
 780static void child_handler(int signo)
 781{
 782        for (;;) {
 783                int status;
 784                pid_t pid = waitpid(-1, &status, WNOHANG);
 785
 786                if (pid > 0) {
 787                        unsigned reaped = children_reaped;
 788                        if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
 789                                pid = -pid;
 790                        dead_child[reaped % MAX_CHILDREN] = pid;
 791                        children_reaped = reaped + 1;
 792                        write(child_handler_pipe[1], &status, 1);
 793                        continue;
 794                }
 795                break;
 796        }
 797}
 798
 799static int set_reuse_addr(int sockfd)
 800{
 801        int on = 1;
 802
 803        if (!reuseaddr)
 804                return 0;
 805        return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 806                          &on, sizeof(on));
 807}
 808
 809#ifndef NO_IPV6
 810
 811static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 812{
 813        int socknum = 0, *socklist = NULL;
 814        int maxfd = -1;
 815        char pbuf[NI_MAXSERV];
 816        struct addrinfo hints, *ai0, *ai;
 817        int gai;
 818        long flags;
 819
 820        sprintf(pbuf, "%d", listen_port);
 821        memset(&hints, 0, sizeof(hints));
 822        hints.ai_family = AF_UNSPEC;
 823        hints.ai_socktype = SOCK_STREAM;
 824        hints.ai_protocol = IPPROTO_TCP;
 825        hints.ai_flags = AI_PASSIVE;
 826
 827        gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 828        if (gai)
 829                die("getaddrinfo() failed: %s\n", gai_strerror(gai));
 830
 831        for (ai = ai0; ai; ai = ai->ai_next) {
 832                int sockfd;
 833
 834                sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 835                if (sockfd < 0)
 836                        continue;
 837                if (sockfd >= FD_SETSIZE) {
 838                        error("too large socket descriptor.");
 839                        close(sockfd);
 840                        continue;
 841                }
 842
 843#ifdef IPV6_V6ONLY
 844                if (ai->ai_family == AF_INET6) {
 845                        int on = 1;
 846                        setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 847                                   &on, sizeof(on));
 848                        /* Note: error is not fatal */
 849                }
 850#endif
 851
 852                if (set_reuse_addr(sockfd)) {
 853                        close(sockfd);
 854                        continue;
 855                }
 856
 857                if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 858                        close(sockfd);
 859                        continue;       /* not fatal */
 860                }
 861                if (listen(sockfd, 5) < 0) {
 862                        close(sockfd);
 863                        continue;       /* not fatal */
 864                }
 865
 866                flags = fcntl(sockfd, F_GETFD, 0);
 867                if (flags >= 0)
 868                        fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 869
 870                socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
 871                socklist[socknum++] = sockfd;
 872
 873                if (maxfd < sockfd)
 874                        maxfd = sockfd;
 875        }
 876
 877        freeaddrinfo(ai0);
 878
 879        *socklist_p = socklist;
 880        return socknum;
 881}
 882
 883#else /* NO_IPV6 */
 884
 885static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 886{
 887        struct sockaddr_in sin;
 888        int sockfd;
 889        long flags;
 890
 891        memset(&sin, 0, sizeof sin);
 892        sin.sin_family = AF_INET;
 893        sin.sin_port = htons(listen_port);
 894
 895        if (listen_addr) {
 896                /* Well, host better be an IP address here. */
 897                if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 898                        return 0;
 899        } else {
 900                sin.sin_addr.s_addr = htonl(INADDR_ANY);
 901        }
 902
 903        sockfd = socket(AF_INET, SOCK_STREAM, 0);
 904        if (sockfd < 0)
 905                return 0;
 906
 907        if (set_reuse_addr(sockfd)) {
 908                close(sockfd);
 909                return 0;
 910        }
 911
 912        if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 913                close(sockfd);
 914                return 0;
 915        }
 916
 917        if (listen(sockfd, 5) < 0) {
 918                close(sockfd);
 919                return 0;
 920        }
 921
 922        flags = fcntl(sockfd, F_GETFD, 0);
 923        if (flags >= 0)
 924                fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 925
 926        *socklist_p = xmalloc(sizeof(int));
 927        **socklist_p = sockfd;
 928        return 1;
 929}
 930
 931#endif
 932
 933static int service_loop(int socknum, int *socklist)
 934{
 935        struct pollfd *pfd;
 936        int i;
 937
 938        if (pipe(child_handler_pipe) < 0)
 939                die ("Could not set up pipe for child handler");
 940
 941        pfd = xcalloc(socknum + 1, sizeof(struct pollfd));
 942
 943        for (i = 0; i < socknum; i++) {
 944                pfd[i].fd = socklist[i];
 945                pfd[i].events = POLLIN;
 946        }
 947        pfd[socknum].fd = child_handler_pipe[0];
 948        pfd[socknum].events = POLLIN;
 949
 950        signal(SIGCHLD, child_handler);
 951
 952        for (;;) {
 953                int i;
 954
 955                if (poll(pfd, socknum + 1, -1) < 0) {
 956                        if (errno != EINTR) {
 957                                error("poll failed, resuming: %s",
 958                                      strerror(errno));
 959                                sleep(1);
 960                        }
 961                        continue;
 962                }
 963                if (pfd[socknum].revents & POLLIN) {
 964                        read(child_handler_pipe[0], &i, 1);
 965                        check_dead_children();
 966                }
 967
 968                for (i = 0; i < socknum; i++) {
 969                        if (pfd[i].revents & POLLIN) {
 970                                struct sockaddr_storage ss;
 971                                unsigned int sslen = sizeof(ss);
 972                                int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
 973                                if (incoming < 0) {
 974                                        switch (errno) {
 975                                        case EAGAIN:
 976                                        case EINTR:
 977                                        case ECONNABORTED:
 978                                                continue;
 979                                        default:
 980                                                die("accept returned %s", strerror(errno));
 981                                        }
 982                                }
 983                                handle(incoming, (struct sockaddr *)&ss, sslen);
 984                        }
 985                }
 986        }
 987}
 988
 989/* if any standard file descriptor is missing open it to /dev/null */
 990static void sanitize_stdfds(void)
 991{
 992        int fd = open("/dev/null", O_RDWR, 0);
 993        while (fd != -1 && fd < 2)
 994                fd = dup(fd);
 995        if (fd == -1)
 996                die("open /dev/null or dup failed: %s", strerror(errno));
 997        if (fd > 2)
 998                close(fd);
 999}
1000
1001static void daemonize(void)
1002{
1003        switch (fork()) {
1004                case 0:
1005                        break;
1006                case -1:
1007                        die("fork failed: %s", strerror(errno));
1008                default:
1009                        exit(0);
1010        }
1011        if (setsid() == -1)
1012                die("setsid failed: %s", strerror(errno));
1013        close(0);
1014        close(1);
1015        close(2);
1016        sanitize_stdfds();
1017}
1018
1019static void store_pid(const char *path)
1020{
1021        FILE *f = fopen(path, "w");
1022        if (!f)
1023                die("cannot open pid file %s: %s", path, strerror(errno));
1024        if (fprintf(f, "%d\n", getpid()) < 0 || fclose(f) != 0)
1025                die("failed to write pid file %s: %s", path, strerror(errno));
1026}
1027
1028static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
1029{
1030        int socknum, *socklist;
1031
1032        socknum = socksetup(listen_addr, listen_port, &socklist);
1033        if (socknum == 0)
1034                die("unable to allocate any listen sockets on host %s port %u",
1035                    listen_addr, listen_port);
1036
1037        if (pass && gid &&
1038            (initgroups(pass->pw_name, gid) || setgid (gid) ||
1039             setuid(pass->pw_uid)))
1040                die("cannot drop privileges");
1041
1042        return service_loop(socknum, socklist);
1043}
1044
1045int main(int argc, char **argv)
1046{
1047        int listen_port = 0;
1048        char *listen_addr = NULL;
1049        int inetd_mode = 0;
1050        const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1051        int detach = 0;
1052        struct passwd *pass = NULL;
1053        struct group *group;
1054        gid_t gid = 0;
1055        int i;
1056
1057        /* Without this we cannot rely on waitpid() to tell
1058         * what happened to our children.
1059         */
1060        signal(SIGCHLD, SIG_DFL);
1061
1062        for (i = 1; i < argc; i++) {
1063                char *arg = argv[i];
1064
1065                if (!prefixcmp(arg, "--listen=")) {
1066                    char *p = arg + 9;
1067                    char *ph = listen_addr = xmalloc(strlen(arg + 9) + 1);
1068                    while (*p)
1069                        *ph++ = tolower(*p++);
1070                    *ph = 0;
1071                    continue;
1072                }
1073                if (!prefixcmp(arg, "--port=")) {
1074                        char *end;
1075                        unsigned long n;
1076                        n = strtoul(arg+7, &end, 0);
1077                        if (arg[7] && !*end) {
1078                                listen_port = n;
1079                                continue;
1080                        }
1081                }
1082                if (!strcmp(arg, "--inetd")) {
1083                        inetd_mode = 1;
1084                        log_syslog = 1;
1085                        continue;
1086                }
1087                if (!strcmp(arg, "--verbose")) {
1088                        verbose = 1;
1089                        continue;
1090                }
1091                if (!strcmp(arg, "--syslog")) {
1092                        log_syslog = 1;
1093                        continue;
1094                }
1095                if (!strcmp(arg, "--export-all")) {
1096                        export_all_trees = 1;
1097                        continue;
1098                }
1099                if (!prefixcmp(arg, "--timeout=")) {
1100                        timeout = atoi(arg+10);
1101                        continue;
1102                }
1103                if (!prefixcmp(arg, "--init-timeout=")) {
1104                        init_timeout = atoi(arg+15);
1105                        continue;
1106                }
1107                if (!strcmp(arg, "--strict-paths")) {
1108                        strict_paths = 1;
1109                        continue;
1110                }
1111                if (!prefixcmp(arg, "--base-path=")) {
1112                        base_path = arg+12;
1113                        continue;
1114                }
1115                if (!strcmp(arg, "--base-path-relaxed")) {
1116                        base_path_relaxed = 1;
1117                        continue;
1118                }
1119                if (!prefixcmp(arg, "--interpolated-path=")) {
1120                        interpolated_path = arg+20;
1121                        continue;
1122                }
1123                if (!strcmp(arg, "--reuseaddr")) {
1124                        reuseaddr = 1;
1125                        continue;
1126                }
1127                if (!strcmp(arg, "--user-path")) {
1128                        user_path = "";
1129                        continue;
1130                }
1131                if (!prefixcmp(arg, "--user-path=")) {
1132                        user_path = arg + 12;
1133                        continue;
1134                }
1135                if (!prefixcmp(arg, "--pid-file=")) {
1136                        pid_file = arg + 11;
1137                        continue;
1138                }
1139                if (!strcmp(arg, "--detach")) {
1140                        detach = 1;
1141                        log_syslog = 1;
1142                        continue;
1143                }
1144                if (!prefixcmp(arg, "--user=")) {
1145                        user_name = arg + 7;
1146                        continue;
1147                }
1148                if (!prefixcmp(arg, "--group=")) {
1149                        group_name = arg + 8;
1150                        continue;
1151                }
1152                if (!prefixcmp(arg, "--enable=")) {
1153                        enable_service(arg + 9, 1);
1154                        continue;
1155                }
1156                if (!prefixcmp(arg, "--disable=")) {
1157                        enable_service(arg + 10, 0);
1158                        continue;
1159                }
1160                if (!prefixcmp(arg, "--allow-override=")) {
1161                        make_service_overridable(arg + 17, 1);
1162                        continue;
1163                }
1164                if (!prefixcmp(arg, "--forbid-override=")) {
1165                        make_service_overridable(arg + 18, 0);
1166                        continue;
1167                }
1168                if (!strcmp(arg, "--")) {
1169                        ok_paths = &argv[i+1];
1170                        break;
1171                } else if (arg[0] != '-') {
1172                        ok_paths = &argv[i];
1173                        break;
1174                }
1175
1176                usage(daemon_usage);
1177        }
1178
1179        if (log_syslog) {
1180                openlog("git-daemon", 0, LOG_DAEMON);
1181                set_die_routine(daemon_die);
1182        }
1183
1184        if (inetd_mode && (group_name || user_name))
1185                die("--user and --group are incompatible with --inetd");
1186
1187        if (inetd_mode && (listen_port || listen_addr))
1188                die("--listen= and --port= are incompatible with --inetd");
1189        else if (listen_port == 0)
1190                listen_port = DEFAULT_GIT_PORT;
1191
1192        if (group_name && !user_name)
1193                die("--group supplied without --user");
1194
1195        if (user_name) {
1196                pass = getpwnam(user_name);
1197                if (!pass)
1198                        die("user not found - %s", user_name);
1199
1200                if (!group_name)
1201                        gid = pass->pw_gid;
1202                else {
1203                        group = getgrnam(group_name);
1204                        if (!group)
1205                                die("group not found - %s", group_name);
1206
1207                        gid = group->gr_gid;
1208                }
1209        }
1210
1211        if (strict_paths && (!ok_paths || !*ok_paths))
1212                die("option --strict-paths requires a whitelist");
1213
1214        if (base_path) {
1215                struct stat st;
1216
1217                if (stat(base_path, &st) || !S_ISDIR(st.st_mode))
1218                        die("base-path '%s' does not exist or "
1219                            "is not a directory", base_path);
1220        }
1221
1222        if (inetd_mode) {
1223                struct sockaddr_storage ss;
1224                struct sockaddr *peer = (struct sockaddr *)&ss;
1225                socklen_t slen = sizeof(ss);
1226
1227                freopen("/dev/null", "w", stderr);
1228
1229                if (getpeername(0, peer, &slen))
1230                        peer = NULL;
1231
1232                return execute(peer);
1233        }
1234
1235        if (detach)
1236                daemonize();
1237        else
1238                sanitize_stdfds();
1239
1240        if (pid_file)
1241                store_pid(pid_file);
1242
1243        return serve(listen_addr, listen_port, pass, gid);
1244}