daemon.con commit diff format documentation: describe raw combined diff format (3b559ea)
   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
  12static int log_syslog;
  13static int verbose;
  14static int reuseaddr;
  15
  16static const char daemon_usage[] =
  17"git-daemon [--verbose] [--syslog] [--export-all]\n"
  18"           [--timeout=n] [--init-timeout=n] [--strict-paths]\n"
  19"           [--base-path=path] [--user-path | --user-path=path]\n"
  20"           [--interpolated-path=path]\n"
  21"           [--reuseaddr] [--detach] [--pid-file=file]\n"
  22"           [--[enable|disable|allow-override|forbid-override]=service]\n"
  23"           [--inetd | [--listen=host_or_ipaddr] [--port=n]\n"
  24"                      [--user=user [--group=group]]\n"
  25"           [directory...]";
  26
  27/* List of acceptable pathname prefixes */
  28static char **ok_paths;
  29static int strict_paths;
  30
  31/* If this is set, git-daemon-export-ok is not required */
  32static int export_all_trees;
  33
  34/* Take all paths relative to this one if non-NULL */
  35static char *base_path;
  36static char *interpolated_path;
  37
  38/* Flag indicating client sent extra args. */
  39static int saw_extended_args;
  40
  41/* If defined, ~user notation is allowed and the string is inserted
  42 * after ~user/.  E.g. a request to git://host/~alice/frotz would
  43 * go to /home/alice/pub_git/frotz with --user-path=pub_git.
  44 */
  45static const char *user_path;
  46
  47/* Timeout, and initial timeout */
  48static unsigned int timeout;
  49static unsigned int init_timeout;
  50
  51/*
  52 * Static table for now.  Ugh.
  53 * Feel free to make dynamic as needed.
  54 */
  55#define INTERP_SLOT_HOST        (0)
  56#define INTERP_SLOT_CANON_HOST  (1)
  57#define INTERP_SLOT_IP          (2)
  58#define INTERP_SLOT_PORT        (3)
  59#define INTERP_SLOT_DIR         (4)
  60#define INTERP_SLOT_PERCENT     (5)
  61
  62static struct interp interp_table[] = {
  63        { "%H", 0},
  64        { "%CH", 0},
  65        { "%IP", 0},
  66        { "%P", 0},
  67        { "%D", 0},
  68        { "%%", 0},
  69};
  70
  71
  72static void logreport(int priority, const char *err, va_list params)
  73{
  74        /* We should do a single write so that it is atomic and output
  75         * of several processes do not get intermingled. */
  76        char buf[1024];
  77        int buflen;
  78        int maxlen, msglen;
  79
  80        /* sizeof(buf) should be big enough for "[pid] \n" */
  81        buflen = snprintf(buf, sizeof(buf), "[%ld] ", (long) getpid());
  82
  83        maxlen = sizeof(buf) - buflen - 1; /* -1 for our own LF */
  84        msglen = vsnprintf(buf + buflen, maxlen, err, params);
  85
  86        if (log_syslog) {
  87                syslog(priority, "%s", buf);
  88                return;
  89        }
  90
  91        /* maxlen counted our own LF but also counts space given to
  92         * vsnprintf for the terminating NUL.  We want to make sure that
  93         * we have space for our own LF and NUL after the "meat" of the
  94         * message, so truncate it at maxlen - 1.
  95         */
  96        if (msglen > maxlen - 1)
  97                msglen = maxlen - 1;
  98        else if (msglen < 0)
  99                msglen = 0; /* Protect against weird return values. */
 100        buflen += msglen;
 101
 102        buf[buflen++] = '\n';
 103        buf[buflen] = '\0';
 104
 105        write_in_full(2, buf, buflen);
 106}
 107
 108static void logerror(const char *err, ...)
 109{
 110        va_list params;
 111        va_start(params, err);
 112        logreport(LOG_ERR, err, params);
 113        va_end(params);
 114}
 115
 116static void loginfo(const char *err, ...)
 117{
 118        va_list params;
 119        if (!verbose)
 120                return;
 121        va_start(params, err);
 122        logreport(LOG_INFO, err, params);
 123        va_end(params);
 124}
 125
 126static void NORETURN daemon_die(const char *err, va_list params)
 127{
 128        logreport(LOG_ERR, err, params);
 129        exit(1);
 130}
 131
 132static int avoid_alias(char *p)
 133{
 134        int sl, ndot;
 135
 136        /* 
 137         * This resurrects the belts and suspenders paranoia check by HPA
 138         * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
 139         * does not do getcwd() based path canonicalizations.
 140         *
 141         * sl becomes true immediately after seeing '/' and continues to
 142         * be true as long as dots continue after that without intervening
 143         * non-dot character.
 144         */
 145        if (!p || (*p != '/' && *p != '~'))
 146                return -1;
 147        sl = 1; ndot = 0;
 148        p++;
 149
 150        while (1) {
 151                char ch = *p++;
 152                if (sl) {
 153                        if (ch == '.')
 154                                ndot++;
 155                        else if (ch == '/') {
 156                                if (ndot < 3)
 157                                        /* reject //, /./ and /../ */
 158                                        return -1;
 159                                ndot = 0;
 160                        }
 161                        else if (ch == 0) {
 162                                if (0 < ndot && ndot < 3)
 163                                        /* reject /.$ and /..$ */
 164                                        return -1;
 165                                return 0;
 166                        }
 167                        else
 168                                sl = ndot = 0;
 169                }
 170                else if (ch == 0)
 171                        return 0;
 172                else if (ch == '/') {
 173                        sl = 1;
 174                        ndot = 0;
 175                }
 176        }
 177}
 178
 179static char *path_ok(struct interp *itable)
 180{
 181        static char rpath[PATH_MAX];
 182        static char interp_path[PATH_MAX];
 183        char *path;
 184        char *dir;
 185
 186        dir = itable[INTERP_SLOT_DIR].value;
 187
 188        if (avoid_alias(dir)) {
 189                logerror("'%s': aliased", dir);
 190                return NULL;
 191        }
 192
 193        if (*dir == '~') {
 194                if (!user_path) {
 195                        logerror("'%s': User-path not allowed", dir);
 196                        return NULL;
 197                }
 198                if (*user_path) {
 199                        /* Got either "~alice" or "~alice/foo";
 200                         * rewrite them to "~alice/%s" or
 201                         * "~alice/%s/foo".
 202                         */
 203                        int namlen, restlen = strlen(dir);
 204                        char *slash = strchr(dir, '/');
 205                        if (!slash)
 206                                slash = dir + restlen;
 207                        namlen = slash - dir;
 208                        restlen -= namlen;
 209                        loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
 210                        snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
 211                                 namlen, dir, user_path, restlen, slash);
 212                        dir = rpath;
 213                }
 214        }
 215        else if (interpolated_path && saw_extended_args) {
 216                if (*dir != '/') {
 217                        /* Allow only absolute */
 218                        logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 219                        return NULL;
 220                }
 221
 222                interpolate(interp_path, PATH_MAX, interpolated_path,
 223                            interp_table, ARRAY_SIZE(interp_table));
 224                loginfo("Interpolated dir '%s'", interp_path);
 225
 226                dir = interp_path;
 227        }
 228        else if (base_path) {
 229                if (*dir != '/') {
 230                        /* Allow only absolute */
 231                        logerror("'%s': Non-absolute path denied (base-path active)", dir);
 232                        return NULL;
 233                }
 234                snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
 235                dir = rpath;
 236        }
 237
 238        path = enter_repo(dir, strict_paths);
 239
 240        if (!path) {
 241                logerror("'%s': unable to chdir or not a git archive", dir);
 242                return NULL;
 243        }
 244
 245        if ( ok_paths && *ok_paths ) {
 246                char **pp;
 247                int pathlen = strlen(path);
 248
 249                /* The validation is done on the paths after enter_repo
 250                 * appends optional {.git,.git/.git} and friends, but 
 251                 * it does not use getcwd().  So if your /pub is
 252                 * a symlink to /mnt/pub, you can whitelist /pub and
 253                 * do not have to say /mnt/pub.
 254                 * Do not say /pub/.
 255                 */
 256                for ( pp = ok_paths ; *pp ; pp++ ) {
 257                        int len = strlen(*pp);
 258                        if (len <= pathlen &&
 259                            !memcmp(*pp, path, len) &&
 260                            (path[len] == '\0' ||
 261                             (!strict_paths && path[len] == '/')))
 262                                return path;
 263                }
 264        }
 265        else {
 266                /* be backwards compatible */
 267                if (!strict_paths)
 268                        return path;
 269        }
 270
 271        logerror("'%s': not in whitelist", path);
 272        return NULL;            /* Fallthrough. Deny by default */
 273}
 274
 275typedef int (*daemon_service_fn)(void);
 276struct daemon_service {
 277        const char *name;
 278        const char *config_name;
 279        daemon_service_fn fn;
 280        int enabled;
 281        int overridable;
 282};
 283
 284static struct daemon_service *service_looking_at;
 285static int service_enabled;
 286
 287static int git_daemon_config(const char *var, const char *value)
 288{
 289        if (!prefixcmp(var, "daemon.") &&
 290            !strcmp(var + 7, service_looking_at->config_name)) {
 291                service_enabled = git_config_bool(var, value);
 292                return 0;
 293        }
 294
 295        /* we are not interested in parsing any other configuration here */
 296        return 0;
 297}
 298
 299static int run_service(struct interp *itable, struct daemon_service *service)
 300{
 301        const char *path;
 302        int enabled = service->enabled;
 303
 304        loginfo("Request %s for '%s'",
 305                service->name,
 306                itable[INTERP_SLOT_DIR].value);
 307
 308        if (!enabled && !service->overridable) {
 309                logerror("'%s': service not enabled.", service->name);
 310                errno = EACCES;
 311                return -1;
 312        }
 313
 314        if (!(path = path_ok(itable)))
 315                return -1;
 316
 317        /*
 318         * Security on the cheap.
 319         *
 320         * We want a readable HEAD, usable "objects" directory, and
 321         * a "git-daemon-export-ok" flag that says that the other side
 322         * is ok with us doing this.
 323         *
 324         * path_ok() uses enter_repo() and does whitelist checking.
 325         * We only need to make sure the repository is exported.
 326         */
 327
 328        if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 329                logerror("'%s': repository not exported.", path);
 330                errno = EACCES;
 331                return -1;
 332        }
 333
 334        if (service->overridable) {
 335                service_looking_at = service;
 336                service_enabled = -1;
 337                git_config(git_daemon_config);
 338                if (0 <= service_enabled)
 339                        enabled = service_enabled;
 340        }
 341        if (!enabled) {
 342                logerror("'%s': service not enabled for '%s'",
 343                         service->name, path);
 344                errno = EACCES;
 345                return -1;
 346        }
 347
 348        /*
 349         * We'll ignore SIGTERM from now on, we have a
 350         * good client.
 351         */
 352        signal(SIGTERM, SIG_IGN);
 353
 354        return service->fn();
 355}
 356
 357static int upload_pack(void)
 358{
 359        /* Timeout as string */
 360        char timeout_buf[64];
 361
 362        snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 363
 364        /* git-upload-pack only ever reads stuff, so this is safe */
 365        execl_git_cmd("upload-pack", "--strict", timeout_buf, ".", NULL);
 366        return -1;
 367}
 368
 369static int upload_archive(void)
 370{
 371        execl_git_cmd("upload-archive", ".", NULL);
 372        return -1;
 373}
 374
 375static int receive_pack(void)
 376{
 377        execl_git_cmd("receive-pack", ".", NULL);
 378        return -1;
 379}
 380
 381static struct daemon_service daemon_service[] = {
 382        { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 383        { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 384        { "receive-pack", "receivepack", receive_pack, 0, 1 },
 385};
 386
 387static void enable_service(const char *name, int ena) {
 388        int i;
 389        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 390                if (!strcmp(daemon_service[i].name, name)) {
 391                        daemon_service[i].enabled = ena;
 392                        return;
 393                }
 394        }
 395        die("No such service %s", name);
 396}
 397
 398static void make_service_overridable(const char *name, int ena) {
 399        int i;
 400        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 401                if (!strcmp(daemon_service[i].name, name)) {
 402                        daemon_service[i].overridable = ena;
 403                        return;
 404                }
 405        }
 406        die("No such service %s", name);
 407}
 408
 409/*
 410 * Separate the "extra args" information as supplied by the client connection.
 411 * Any resulting data is squirreled away in the given interpolation table.
 412 */
 413static void parse_extra_args(struct interp *table, char *extra_args, int buflen)
 414{
 415        char *val;
 416        int vallen;
 417        char *end = extra_args + buflen;
 418
 419        while (extra_args < end && *extra_args) {
 420                saw_extended_args = 1;
 421                if (strncasecmp("host=", extra_args, 5) == 0) {
 422                        val = extra_args + 5;
 423                        vallen = strlen(val) + 1;
 424                        if (*val) {
 425                                /* Split <host>:<port> at colon. */
 426                                char *host = val;
 427                                char *port = strrchr(host, ':');
 428                                if (port) {
 429                                        *port = 0;
 430                                        port++;
 431                                        interp_set_entry(table, INTERP_SLOT_PORT, port);
 432                                }
 433                                interp_set_entry(table, INTERP_SLOT_HOST, host);
 434                        }
 435
 436                        /* On to the next one */
 437                        extra_args = val + vallen;
 438                }
 439        }
 440}
 441
 442void fill_in_extra_table_entries(struct interp *itable)
 443{
 444        char *hp;
 445
 446        /*
 447         * Replace literal host with lowercase-ized hostname.
 448         */
 449        hp = interp_table[INTERP_SLOT_HOST].value;
 450        if (!hp)
 451                return;
 452        for ( ; *hp; hp++)
 453                *hp = tolower(*hp);
 454
 455        /*
 456         * Locate canonical hostname and its IP address.
 457         */
 458#ifndef NO_IPV6
 459        {
 460                struct addrinfo hints;
 461                struct addrinfo *ai, *ai0;
 462                int gai;
 463                static char addrbuf[HOST_NAME_MAX + 1];
 464
 465                memset(&hints, 0, sizeof(hints));
 466                hints.ai_flags = AI_CANONNAME;
 467
 468                gai = getaddrinfo(interp_table[INTERP_SLOT_HOST].value, 0, &hints, &ai0);
 469                if (!gai) {
 470                        for (ai = ai0; ai; ai = ai->ai_next) {
 471                                struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 472
 473                                inet_ntop(AF_INET, &sin_addr->sin_addr,
 474                                          addrbuf, sizeof(addrbuf));
 475                                interp_set_entry(interp_table,
 476                                                 INTERP_SLOT_CANON_HOST, ai->ai_canonname);
 477                                interp_set_entry(interp_table,
 478                                                 INTERP_SLOT_IP, addrbuf);
 479                                break;
 480                        }
 481                        freeaddrinfo(ai0);
 482                }
 483        }
 484#else
 485        {
 486                struct hostent *hent;
 487                struct sockaddr_in sa;
 488                char **ap;
 489                static char addrbuf[HOST_NAME_MAX + 1];
 490
 491                hent = gethostbyname(interp_table[INTERP_SLOT_HOST].value);
 492
 493                ap = hent->h_addr_list;
 494                memset(&sa, 0, sizeof sa);
 495                sa.sin_family = hent->h_addrtype;
 496                sa.sin_port = htons(0);
 497                memcpy(&sa.sin_addr, *ap, hent->h_length);
 498
 499                inet_ntop(hent->h_addrtype, &sa.sin_addr,
 500                          addrbuf, sizeof(addrbuf));
 501
 502                interp_set_entry(interp_table, INTERP_SLOT_CANON_HOST, hent->h_name);
 503                interp_set_entry(interp_table, INTERP_SLOT_IP, addrbuf);
 504        }
 505#endif
 506}
 507
 508
 509static int execute(struct sockaddr *addr)
 510{
 511        static char line[1000];
 512        int pktlen, len, i;
 513
 514        if (addr) {
 515                char addrbuf[256] = "";
 516                int port = -1;
 517
 518                if (addr->sa_family == AF_INET) {
 519                        struct sockaddr_in *sin_addr = (void *) addr;
 520                        inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
 521                        port = sin_addr->sin_port;
 522#ifndef NO_IPV6
 523                } else if (addr && addr->sa_family == AF_INET6) {
 524                        struct sockaddr_in6 *sin6_addr = (void *) addr;
 525
 526                        char *buf = addrbuf;
 527                        *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 528                        inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
 529                        strcat(buf, "]");
 530
 531                        port = sin6_addr->sin6_port;
 532#endif
 533                }
 534                loginfo("Connection from %s:%d", addrbuf, port);
 535        }
 536
 537        alarm(init_timeout ? init_timeout : timeout);
 538        pktlen = packet_read_line(0, line, sizeof(line));
 539        alarm(0);
 540
 541        len = strlen(line);
 542        if (pktlen != len)
 543                loginfo("Extended attributes (%d bytes) exist <%.*s>",
 544                        (int) pktlen - len,
 545                        (int) pktlen - len, line + len + 1);
 546        if (len && line[len-1] == '\n') {
 547                line[--len] = 0;
 548                pktlen--;
 549        }
 550
 551        /*
 552         * Initialize the path interpolation table for this connection.
 553         */
 554        interp_clear_table(interp_table, ARRAY_SIZE(interp_table));
 555        interp_set_entry(interp_table, INTERP_SLOT_PERCENT, "%");
 556
 557        if (len != pktlen) {
 558            parse_extra_args(interp_table, line + len + 1, pktlen - len - 1);
 559            fill_in_extra_table_entries(interp_table);
 560        }
 561
 562        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 563                struct daemon_service *s = &(daemon_service[i]);
 564                int namelen = strlen(s->name);
 565                if (!prefixcmp(line, "git-") &&
 566                    !strncmp(s->name, line + 4, namelen) &&
 567                    line[namelen + 4] == ' ') {
 568                        /*
 569                         * Note: The directory here is probably context sensitive,
 570                         * and might depend on the actual service being performed.
 571                         */
 572                        interp_set_entry(interp_table,
 573                                         INTERP_SLOT_DIR, line + namelen + 5);
 574                        return run_service(interp_table, s);
 575                }
 576        }
 577
 578        logerror("Protocol error: '%s'", line);
 579        return -1;
 580}
 581
 582
 583/*
 584 * We count spawned/reaped separately, just to avoid any
 585 * races when updating them from signals. The SIGCHLD handler
 586 * will only update children_reaped, and the fork logic will
 587 * only update children_spawned.
 588 *
 589 * MAX_CHILDREN should be a power-of-two to make the modulus
 590 * operation cheap. It should also be at least twice
 591 * the maximum number of connections we will ever allow.
 592 */
 593#define MAX_CHILDREN 128
 594
 595static int max_connections = 25;
 596
 597/* These are updated by the signal handler */
 598static volatile unsigned int children_reaped;
 599static pid_t dead_child[MAX_CHILDREN];
 600
 601/* These are updated by the main loop */
 602static unsigned int children_spawned;
 603static unsigned int children_deleted;
 604
 605static struct child {
 606        pid_t pid;
 607        int addrlen;
 608        struct sockaddr_storage address;
 609} live_child[MAX_CHILDREN];
 610
 611static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen)
 612{
 613        live_child[idx].pid = pid;
 614        live_child[idx].addrlen = addrlen;
 615        memcpy(&live_child[idx].address, addr, addrlen);
 616}
 617
 618/*
 619 * Walk from "deleted" to "spawned", and remove child "pid".
 620 *
 621 * We move everything up by one, since the new "deleted" will
 622 * be one higher.
 623 */
 624static void remove_child(pid_t pid, unsigned deleted, unsigned spawned)
 625{
 626        struct child n;
 627
 628        deleted %= MAX_CHILDREN;
 629        spawned %= MAX_CHILDREN;
 630        if (live_child[deleted].pid == pid) {
 631                live_child[deleted].pid = -1;
 632                return;
 633        }
 634        n = live_child[deleted];
 635        for (;;) {
 636                struct child m;
 637                deleted = (deleted + 1) % MAX_CHILDREN;
 638                if (deleted == spawned)
 639                        die("could not find dead child %d\n", pid);
 640                m = live_child[deleted];
 641                live_child[deleted] = n;
 642                if (m.pid == pid)
 643                        return;
 644                n = m;
 645        }
 646}
 647
 648/*
 649 * This gets called if the number of connections grows
 650 * past "max_connections".
 651 *
 652 * We _should_ start off by searching for connections
 653 * from the same IP, and if there is some address wth
 654 * multiple connections, we should kill that first.
 655 *
 656 * As it is, we just "randomly" kill 25% of the connections,
 657 * and our pseudo-random generator sucks too. I have no
 658 * shame.
 659 *
 660 * Really, this is just a place-holder for a _real_ algorithm.
 661 */
 662static void kill_some_children(int signo, unsigned start, unsigned stop)
 663{
 664        start %= MAX_CHILDREN;
 665        stop %= MAX_CHILDREN;
 666        while (start != stop) {
 667                if (!(start & 3))
 668                        kill(live_child[start].pid, signo);
 669                start = (start + 1) % MAX_CHILDREN;
 670        }
 671}
 672
 673static void check_max_connections(void)
 674{
 675        for (;;) {
 676                int active;
 677                unsigned spawned, reaped, deleted;
 678
 679                spawned = children_spawned;
 680                reaped = children_reaped;
 681                deleted = children_deleted;
 682
 683                while (deleted < reaped) {
 684                        pid_t pid = dead_child[deleted % MAX_CHILDREN];
 685                        remove_child(pid, deleted, spawned);
 686                        deleted++;
 687                }
 688                children_deleted = deleted;
 689
 690                active = spawned - deleted;
 691                if (active <= max_connections)
 692                        break;
 693
 694                /* Kill some unstarted connections with SIGTERM */
 695                kill_some_children(SIGTERM, deleted, spawned);
 696                if (active <= max_connections << 1)
 697                        break;
 698
 699                /* If the SIGTERM thing isn't helping use SIGKILL */
 700                kill_some_children(SIGKILL, deleted, spawned);
 701                sleep(1);
 702        }
 703}
 704
 705static void handle(int incoming, struct sockaddr *addr, int addrlen)
 706{
 707        pid_t pid = fork();
 708
 709        if (pid) {
 710                unsigned idx;
 711
 712                close(incoming);
 713                if (pid < 0)
 714                        return;
 715
 716                idx = children_spawned % MAX_CHILDREN;
 717                children_spawned++;
 718                add_child(idx, pid, addr, addrlen);
 719
 720                check_max_connections();
 721                return;
 722        }
 723
 724        dup2(incoming, 0);
 725        dup2(incoming, 1);
 726        close(incoming);
 727
 728        exit(execute(addr));
 729}
 730
 731static void child_handler(int signo)
 732{
 733        for (;;) {
 734                int status;
 735                pid_t pid = waitpid(-1, &status, WNOHANG);
 736
 737                if (pid > 0) {
 738                        unsigned reaped = children_reaped;
 739                        dead_child[reaped % MAX_CHILDREN] = pid;
 740                        children_reaped = reaped + 1;
 741                        /* XXX: Custom logging, since we don't wanna getpid() */
 742                        if (verbose) {
 743                                const char *dead = "";
 744                                if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
 745                                        dead = " (with error)";
 746                                if (log_syslog)
 747                                        syslog(LOG_INFO, "[%d] Disconnected%s", pid, dead);
 748                                else
 749                                        fprintf(stderr, "[%d] Disconnected%s\n", pid, dead);
 750                        }
 751                        continue;
 752                }
 753                break;
 754        }
 755}
 756
 757static int set_reuse_addr(int sockfd)
 758{
 759        int on = 1;
 760
 761        if (!reuseaddr)
 762                return 0;
 763        return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 764                          &on, sizeof(on));
 765}
 766
 767#ifndef NO_IPV6
 768
 769static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 770{
 771        int socknum = 0, *socklist = NULL;
 772        int maxfd = -1;
 773        char pbuf[NI_MAXSERV];
 774        struct addrinfo hints, *ai0, *ai;
 775        int gai;
 776        long flags;
 777
 778        sprintf(pbuf, "%d", listen_port);
 779        memset(&hints, 0, sizeof(hints));
 780        hints.ai_family = AF_UNSPEC;
 781        hints.ai_socktype = SOCK_STREAM;
 782        hints.ai_protocol = IPPROTO_TCP;
 783        hints.ai_flags = AI_PASSIVE;
 784
 785        gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 786        if (gai)
 787                die("getaddrinfo() failed: %s\n", gai_strerror(gai));
 788
 789        for (ai = ai0; ai; ai = ai->ai_next) {
 790                int sockfd;
 791
 792                sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 793                if (sockfd < 0)
 794                        continue;
 795                if (sockfd >= FD_SETSIZE) {
 796                        error("too large socket descriptor.");
 797                        close(sockfd);
 798                        continue;
 799                }
 800
 801#ifdef IPV6_V6ONLY
 802                if (ai->ai_family == AF_INET6) {
 803                        int on = 1;
 804                        setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 805                                   &on, sizeof(on));
 806                        /* Note: error is not fatal */
 807                }
 808#endif
 809
 810                if (set_reuse_addr(sockfd)) {
 811                        close(sockfd);
 812                        continue;
 813                }
 814
 815                if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 816                        close(sockfd);
 817                        continue;       /* not fatal */
 818                }
 819                if (listen(sockfd, 5) < 0) {
 820                        close(sockfd);
 821                        continue;       /* not fatal */
 822                }
 823
 824                flags = fcntl(sockfd, F_GETFD, 0);
 825                if (flags >= 0)
 826                        fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 827
 828                socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
 829                socklist[socknum++] = sockfd;
 830
 831                if (maxfd < sockfd)
 832                        maxfd = sockfd;
 833        }
 834
 835        freeaddrinfo(ai0);
 836
 837        *socklist_p = socklist;
 838        return socknum;
 839}
 840
 841#else /* NO_IPV6 */
 842
 843static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 844{
 845        struct sockaddr_in sin;
 846        int sockfd;
 847        long flags;
 848
 849        memset(&sin, 0, sizeof sin);
 850        sin.sin_family = AF_INET;
 851        sin.sin_port = htons(listen_port);
 852
 853        if (listen_addr) {
 854                /* Well, host better be an IP address here. */
 855                if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 856                        return 0;
 857        } else {
 858                sin.sin_addr.s_addr = htonl(INADDR_ANY);
 859        }
 860
 861        sockfd = socket(AF_INET, SOCK_STREAM, 0);
 862        if (sockfd < 0)
 863                return 0;
 864
 865        if (set_reuse_addr(sockfd)) {
 866                close(sockfd);
 867                return 0;
 868        }
 869
 870        if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 871                close(sockfd);
 872                return 0;
 873        }
 874
 875        if (listen(sockfd, 5) < 0) {
 876                close(sockfd);
 877                return 0;
 878        }
 879
 880        flags = fcntl(sockfd, F_GETFD, 0);
 881        if (flags >= 0)
 882                fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 883
 884        *socklist_p = xmalloc(sizeof(int));
 885        **socklist_p = sockfd;
 886        return 1;
 887}
 888
 889#endif
 890
 891static int service_loop(int socknum, int *socklist)
 892{
 893        struct pollfd *pfd;
 894        int i;
 895
 896        pfd = xcalloc(socknum, sizeof(struct pollfd));
 897
 898        for (i = 0; i < socknum; i++) {
 899                pfd[i].fd = socklist[i];
 900                pfd[i].events = POLLIN;
 901        }
 902
 903        signal(SIGCHLD, child_handler);
 904
 905        for (;;) {
 906                int i;
 907
 908                if (poll(pfd, socknum, -1) < 0) {
 909                        if (errno != EINTR) {
 910                                error("poll failed, resuming: %s",
 911                                      strerror(errno));
 912                                sleep(1);
 913                        }
 914                        continue;
 915                }
 916
 917                for (i = 0; i < socknum; i++) {
 918                        if (pfd[i].revents & POLLIN) {
 919                                struct sockaddr_storage ss;
 920                                unsigned int sslen = sizeof(ss);
 921                                int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
 922                                if (incoming < 0) {
 923                                        switch (errno) {
 924                                        case EAGAIN:
 925                                        case EINTR:
 926                                        case ECONNABORTED:
 927                                                continue;
 928                                        default:
 929                                                die("accept returned %s", strerror(errno));
 930                                        }
 931                                }
 932                                handle(incoming, (struct sockaddr *)&ss, sslen);
 933                        }
 934                }
 935        }
 936}
 937
 938/* if any standard file descriptor is missing open it to /dev/null */
 939static void sanitize_stdfds(void)
 940{
 941        int fd = open("/dev/null", O_RDWR, 0);
 942        while (fd != -1 && fd < 2)
 943                fd = dup(fd);
 944        if (fd == -1)
 945                die("open /dev/null or dup failed: %s", strerror(errno));
 946        if (fd > 2)
 947                close(fd);
 948}
 949
 950static void daemonize(void)
 951{
 952        switch (fork()) {
 953                case 0:
 954                        break;
 955                case -1:
 956                        die("fork failed: %s", strerror(errno));
 957                default:
 958                        exit(0);
 959        }
 960        if (setsid() == -1)
 961                die("setsid failed: %s", strerror(errno));
 962        close(0);
 963        close(1);
 964        close(2);
 965        sanitize_stdfds();
 966}
 967
 968static void store_pid(const char *path)
 969{
 970        FILE *f = fopen(path, "w");
 971        if (!f)
 972                die("cannot open pid file %s: %s", path, strerror(errno));
 973        fprintf(f, "%d\n", getpid());
 974        fclose(f);
 975}
 976
 977static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
 978{
 979        int socknum, *socklist;
 980
 981        socknum = socksetup(listen_addr, listen_port, &socklist);
 982        if (socknum == 0)
 983                die("unable to allocate any listen sockets on host %s port %u",
 984                    listen_addr, listen_port);
 985
 986        if (pass && gid &&
 987            (initgroups(pass->pw_name, gid) || setgid (gid) ||
 988             setuid(pass->pw_uid)))
 989                die("cannot drop privileges");
 990
 991        return service_loop(socknum, socklist);
 992}
 993
 994int main(int argc, char **argv)
 995{
 996        int listen_port = 0;
 997        char *listen_addr = NULL;
 998        int inetd_mode = 0;
 999        const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1000        int detach = 0;
1001        struct passwd *pass = NULL;
1002        struct group *group;
1003        gid_t gid = 0;
1004        int i;
1005
1006        /* Without this we cannot rely on waitpid() to tell
1007         * what happened to our children.
1008         */
1009        signal(SIGCHLD, SIG_DFL);
1010
1011        for (i = 1; i < argc; i++) {
1012                char *arg = argv[i];
1013
1014                if (!prefixcmp(arg, "--listen=")) {
1015                    char *p = arg + 9;
1016                    char *ph = listen_addr = xmalloc(strlen(arg + 9) + 1);
1017                    while (*p)
1018                        *ph++ = tolower(*p++);
1019                    *ph = 0;
1020                    continue;
1021                }
1022                if (!prefixcmp(arg, "--port=")) {
1023                        char *end;
1024                        unsigned long n;
1025                        n = strtoul(arg+7, &end, 0);
1026                        if (arg[7] && !*end) {
1027                                listen_port = n;
1028                                continue;
1029                        }
1030                }
1031                if (!strcmp(arg, "--inetd")) {
1032                        inetd_mode = 1;
1033                        log_syslog = 1;
1034                        continue;
1035                }
1036                if (!strcmp(arg, "--verbose")) {
1037                        verbose = 1;
1038                        continue;
1039                }
1040                if (!strcmp(arg, "--syslog")) {
1041                        log_syslog = 1;
1042                        continue;
1043                }
1044                if (!strcmp(arg, "--export-all")) {
1045                        export_all_trees = 1;
1046                        continue;
1047                }
1048                if (!prefixcmp(arg, "--timeout=")) {
1049                        timeout = atoi(arg+10);
1050                        continue;
1051                }
1052                if (!prefixcmp(arg, "--init-timeout=")) {
1053                        init_timeout = atoi(arg+15);
1054                        continue;
1055                }
1056                if (!strcmp(arg, "--strict-paths")) {
1057                        strict_paths = 1;
1058                        continue;
1059                }
1060                if (!prefixcmp(arg, "--base-path=")) {
1061                        base_path = arg+12;
1062                        continue;
1063                }
1064                if (!prefixcmp(arg, "--interpolated-path=")) {
1065                        interpolated_path = arg+20;
1066                        continue;
1067                }
1068                if (!strcmp(arg, "--reuseaddr")) {
1069                        reuseaddr = 1;
1070                        continue;
1071                }
1072                if (!strcmp(arg, "--user-path")) {
1073                        user_path = "";
1074                        continue;
1075                }
1076                if (!prefixcmp(arg, "--user-path=")) {
1077                        user_path = arg + 12;
1078                        continue;
1079                }
1080                if (!prefixcmp(arg, "--pid-file=")) {
1081                        pid_file = arg + 11;
1082                        continue;
1083                }
1084                if (!strcmp(arg, "--detach")) {
1085                        detach = 1;
1086                        log_syslog = 1;
1087                        continue;
1088                }
1089                if (!prefixcmp(arg, "--user=")) {
1090                        user_name = arg + 7;
1091                        continue;
1092                }
1093                if (!prefixcmp(arg, "--group=")) {
1094                        group_name = arg + 8;
1095                        continue;
1096                }
1097                if (!prefixcmp(arg, "--enable=")) {
1098                        enable_service(arg + 9, 1);
1099                        continue;
1100                }
1101                if (!prefixcmp(arg, "--disable=")) {
1102                        enable_service(arg + 10, 0);
1103                        continue;
1104                }
1105                if (!prefixcmp(arg, "--allow-override=")) {
1106                        make_service_overridable(arg + 17, 1);
1107                        continue;
1108                }
1109                if (!prefixcmp(arg, "--forbid-override=")) {
1110                        make_service_overridable(arg + 18, 0);
1111                        continue;
1112                }
1113                if (!strcmp(arg, "--")) {
1114                        ok_paths = &argv[i+1];
1115                        break;
1116                } else if (arg[0] != '-') {
1117                        ok_paths = &argv[i];
1118                        break;
1119                }
1120
1121                usage(daemon_usage);
1122        }
1123
1124        if (inetd_mode && (group_name || user_name))
1125                die("--user and --group are incompatible with --inetd");
1126
1127        if (inetd_mode && (listen_port || listen_addr))
1128                die("--listen= and --port= are incompatible with --inetd");
1129        else if (listen_port == 0)
1130                listen_port = DEFAULT_GIT_PORT;
1131
1132        if (group_name && !user_name)
1133                die("--group supplied without --user");
1134
1135        if (user_name) {
1136                pass = getpwnam(user_name);
1137                if (!pass)
1138                        die("user not found - %s", user_name);
1139
1140                if (!group_name)
1141                        gid = pass->pw_gid;
1142                else {
1143                        group = getgrnam(group_name);
1144                        if (!group)
1145                                die("group not found - %s", group_name);
1146
1147                        gid = group->gr_gid;
1148                }
1149        }
1150
1151        if (log_syslog) {
1152                openlog("git-daemon", 0, LOG_DAEMON);
1153                set_die_routine(daemon_die);
1154        }
1155
1156        if (strict_paths && (!ok_paths || !*ok_paths))
1157                die("option --strict-paths requires a whitelist");
1158
1159        if (inetd_mode) {
1160                struct sockaddr_storage ss;
1161                struct sockaddr *peer = (struct sockaddr *)&ss;
1162                socklen_t slen = sizeof(ss);
1163
1164                freopen("/dev/null", "w", stderr);
1165
1166                if (getpeername(0, peer, &slen))
1167                        peer = NULL;
1168
1169                return execute(peer);
1170        }
1171
1172        if (detach)
1173                daemonize();
1174        else
1175                sanitize_stdfds();
1176
1177        if (pid_file)
1178                store_pid(pid_file);
1179
1180        return serve(listen_addr, listen_port, pass, gid);
1181}