Andrew's git / gitweb.git / daemon.c
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daemon.con commit refs: improve comments about "reading" argument of "resolve_ref" (4886b89)
   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;
  19
  20static const char daemon_usage[] =
  21"git daemon [--verbose] [--syslog] [--export-all]\n"
  22"           [--timeout=n] [--init-timeout=n] [--max-connections=n]\n"
  23"           [--strict-paths] [--base-path=path] [--base-path-relaxed]\n"
  24"           [--user-path | --user-path=path]\n"
  25"           [--interpolated-path=path]\n"
  26"           [--reuseaddr] [--detach] [--pid-file=file]\n"
  27"           [--[enable|disable|allow-override|forbid-override]=service]\n"
  28"           [--inetd | [--listen=host_or_ipaddr] [--port=n]\n"
  29"                      [--user=user [--group=group]]\n"
  30"           [directory...]";
  31
  32/* List of acceptable pathname prefixes */
  33static char **ok_paths;
  34static int strict_paths;
  35
  36/* If this is set, git-daemon-export-ok is not required */
  37static int export_all_trees;
  38
  39/* Take all paths relative to this one if non-NULL */
  40static char *base_path;
  41static char *interpolated_path;
  42static int base_path_relaxed;
  43
  44/* Flag indicating client sent extra args. */
  45static int saw_extended_args;
  46
  47/* If defined, ~user notation is allowed and the string is inserted
  48 * after ~user/.  E.g. a request to git://host/~alice/frotz would
  49 * go to /home/alice/pub_git/frotz with --user-path=pub_git.
  50 */
  51static const char *user_path;
  52
  53/* Timeout, and initial timeout */
  54static unsigned int timeout;
  55static unsigned int init_timeout;
  56
  57/*
  58 * Static table for now.  Ugh.
  59 * Feel free to make dynamic as needed.
  60 */
  61#define INTERP_SLOT_HOST        (0)
  62#define INTERP_SLOT_CANON_HOST  (1)
  63#define INTERP_SLOT_IP          (2)
  64#define INTERP_SLOT_PORT        (3)
  65#define INTERP_SLOT_DIR         (4)
  66#define INTERP_SLOT_PERCENT     (5)
  67
  68static struct interp interp_table[] = {
  69        { "%H", 0},
  70        { "%CH", 0},
  71        { "%IP", 0},
  72        { "%P", 0},
  73        { "%D", 0},
  74        { "%%", 0},
  75};
  76
  77
  78static void logreport(int priority, const char *err, va_list params)
  79{
  80        if (log_syslog) {
  81                char buf[1024];
  82                vsnprintf(buf, sizeof(buf), err, params);
  83                syslog(priority, "%s", buf);
  84        } else {
  85                /*
  86                 * Since stderr is set to linebuffered mode, the
  87                 * logging of different processes will not overlap
  88                 */
  89                fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
  90                vfprintf(stderr, err, params);
  91                fputc('\n', stderr);
  92        }
  93}
  94
  95static void logerror(const char *err, ...)
  96{
  97        va_list params;
  98        va_start(params, err);
  99        logreport(LOG_ERR, err, params);
 100        va_end(params);
 101}
 102
 103static void loginfo(const char *err, ...)
 104{
 105        va_list params;
 106        if (!verbose)
 107                return;
 108        va_start(params, err);
 109        logreport(LOG_INFO, err, params);
 110        va_end(params);
 111}
 112
 113static void NORETURN daemon_die(const char *err, va_list params)
 114{
 115        logreport(LOG_ERR, err, params);
 116        exit(1);
 117}
 118
 119static int avoid_alias(char *p)
 120{
 121        int sl, ndot;
 122
 123        /*
 124         * This resurrects the belts and suspenders paranoia check by HPA
 125         * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
 126         * does not do getcwd() based path canonicalizations.
 127         *
 128         * sl becomes true immediately after seeing '/' and continues to
 129         * be true as long as dots continue after that without intervening
 130         * non-dot character.
 131         */
 132        if (!p || (*p != '/' && *p != '~'))
 133                return -1;
 134        sl = 1; ndot = 0;
 135        p++;
 136
 137        while (1) {
 138                char ch = *p++;
 139                if (sl) {
 140                        if (ch == '.')
 141                                ndot++;
 142                        else if (ch == '/') {
 143                                if (ndot < 3)
 144                                        /* reject //, /./ and /../ */
 145                                        return -1;
 146                                ndot = 0;
 147                        }
 148                        else if (ch == 0) {
 149                                if (0 < ndot && ndot < 3)
 150                                        /* reject /.$ and /..$ */
 151                                        return -1;
 152                                return 0;
 153                        }
 154                        else
 155                                sl = ndot = 0;
 156                }
 157                else if (ch == 0)
 158                        return 0;
 159                else if (ch == '/') {
 160                        sl = 1;
 161                        ndot = 0;
 162                }
 163        }
 164}
 165
 166static char *path_ok(struct interp *itable)
 167{
 168        static char rpath[PATH_MAX];
 169        static char interp_path[PATH_MAX];
 170        int retried_path = 0;
 171        char *path;
 172        char *dir;
 173
 174        dir = itable[INTERP_SLOT_DIR].value;
 175
 176        if (avoid_alias(dir)) {
 177                logerror("'%s': aliased", dir);
 178                return NULL;
 179        }
 180
 181        if (*dir == '~') {
 182                if (!user_path) {
 183                        logerror("'%s': User-path not allowed", dir);
 184                        return NULL;
 185                }
 186                if (*user_path) {
 187                        /* Got either "~alice" or "~alice/foo";
 188                         * rewrite them to "~alice/%s" or
 189                         * "~alice/%s/foo".
 190                         */
 191                        int namlen, restlen = strlen(dir);
 192                        char *slash = strchr(dir, '/');
 193                        if (!slash)
 194                                slash = dir + restlen;
 195                        namlen = slash - dir;
 196                        restlen -= namlen;
 197                        loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
 198                        snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
 199                                 namlen, dir, user_path, restlen, slash);
 200                        dir = rpath;
 201                }
 202        }
 203        else if (interpolated_path && saw_extended_args) {
 204                if (*dir != '/') {
 205                        /* Allow only absolute */
 206                        logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 207                        return NULL;
 208                }
 209
 210                interpolate(interp_path, PATH_MAX, interpolated_path,
 211                            interp_table, ARRAY_SIZE(interp_table));
 212                loginfo("Interpolated dir '%s'", interp_path);
 213
 214                dir = interp_path;
 215        }
 216        else if (base_path) {
 217                if (*dir != '/') {
 218                        /* Allow only absolute */
 219                        logerror("'%s': Non-absolute path denied (base-path active)", dir);
 220                        return NULL;
 221                }
 222                snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
 223                dir = rpath;
 224        }
 225
 226        do {
 227                path = enter_repo(dir, strict_paths);
 228                if (path)
 229                        break;
 230
 231                /*
 232                 * if we fail and base_path_relaxed is enabled, try without
 233                 * prefixing the base path
 234                 */
 235                if (base_path && base_path_relaxed && !retried_path) {
 236                        dir = itable[INTERP_SLOT_DIR].value;
 237                        retried_path = 1;
 238                        continue;
 239                }
 240                break;
 241        } while (1);
 242
 243        if (!path) {
 244                logerror("'%s': unable to chdir or not a git archive", dir);
 245                return NULL;
 246        }
 247
 248        if ( ok_paths && *ok_paths ) {
 249                char **pp;
 250                int pathlen = strlen(path);
 251
 252                /* The validation is done on the paths after enter_repo
 253                 * appends optional {.git,.git/.git} and friends, but
 254                 * it does not use getcwd().  So if your /pub is
 255                 * a symlink to /mnt/pub, you can whitelist /pub and
 256                 * do not have to say /mnt/pub.
 257                 * Do not say /pub/.
 258                 */
 259                for ( pp = ok_paths ; *pp ; pp++ ) {
 260                        int len = strlen(*pp);
 261                        if (len <= pathlen &&
 262                            !memcmp(*pp, path, len) &&
 263                            (path[len] == '\0' ||
 264                             (!strict_paths && path[len] == '/')))
 265                                return path;
 266                }
 267        }
 268        else {
 269                /* be backwards compatible */
 270                if (!strict_paths)
 271                        return path;
 272        }
 273
 274        logerror("'%s': not in whitelist", path);
 275        return NULL;            /* Fallthrough. Deny by default */
 276}
 277
 278typedef int (*daemon_service_fn)(void);
 279struct daemon_service {
 280        const char *name;
 281        const char *config_name;
 282        daemon_service_fn fn;
 283        int enabled;
 284        int overridable;
 285};
 286
 287static struct daemon_service *service_looking_at;
 288static int service_enabled;
 289
 290static int git_daemon_config(const char *var, const char *value, void *cb)
 291{
 292        if (!prefixcmp(var, "daemon.") &&
 293            !strcmp(var + 7, service_looking_at->config_name)) {
 294                service_enabled = git_config_bool(var, value);
 295                return 0;
 296        }
 297
 298        /* we are not interested in parsing any other configuration here */
 299        return 0;
 300}
 301
 302static int run_service(struct interp *itable, struct daemon_service *service)
 303{
 304        const char *path;
 305        int enabled = service->enabled;
 306
 307        loginfo("Request %s for '%s'",
 308                service->name,
 309                itable[INTERP_SLOT_DIR].value);
 310
 311        if (!enabled && !service->overridable) {
 312                logerror("'%s': service not enabled.", service->name);
 313                errno = EACCES;
 314                return -1;
 315        }
 316
 317        if (!(path = path_ok(itable)))
 318                return -1;
 319
 320        /*
 321         * Security on the cheap.
 322         *
 323         * We want a readable HEAD, usable "objects" directory, and
 324         * a "git-daemon-export-ok" flag that says that the other side
 325         * is ok with us doing this.
 326         *
 327         * path_ok() uses enter_repo() and does whitelist checking.
 328         * We only need to make sure the repository is exported.
 329         */
 330
 331        if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 332                logerror("'%s': repository not exported.", path);
 333                errno = EACCES;
 334                return -1;
 335        }
 336
 337        if (service->overridable) {
 338                service_looking_at = service;
 339                service_enabled = -1;
 340                git_config(git_daemon_config, NULL);
 341                if (0 <= service_enabled)
 342                        enabled = service_enabled;
 343        }
 344        if (!enabled) {
 345                logerror("'%s': service not enabled for '%s'",
 346                         service->name, path);
 347                errno = EACCES;
 348                return -1;
 349        }
 350
 351        /*
 352         * We'll ignore SIGTERM from now on, we have a
 353         * good client.
 354         */
 355        signal(SIGTERM, SIG_IGN);
 356
 357        return service->fn();
 358}
 359
 360static int upload_pack(void)
 361{
 362        /* Timeout as string */
 363        char timeout_buf[64];
 364
 365        snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 366
 367        /* git-upload-pack only ever reads stuff, so this is safe */
 368        execl_git_cmd("upload-pack", "--strict", timeout_buf, ".", NULL);
 369        return -1;
 370}
 371
 372static int upload_archive(void)
 373{
 374        execl_git_cmd("upload-archive", ".", NULL);
 375        return -1;
 376}
 377
 378static int receive_pack(void)
 379{
 380        execl_git_cmd("receive-pack", ".", NULL);
 381        return -1;
 382}
 383
 384static struct daemon_service daemon_service[] = {
 385        { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 386        { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 387        { "receive-pack", "receivepack", receive_pack, 0, 1 },
 388};
 389
 390static void enable_service(const char *name, int ena)
 391{
 392        int i;
 393        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 394                if (!strcmp(daemon_service[i].name, name)) {
 395                        daemon_service[i].enabled = ena;
 396                        return;
 397                }
 398        }
 399        die("No such service %s", name);
 400}
 401
 402static void make_service_overridable(const char *name, int ena)
 403{
 404        int i;
 405        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 406                if (!strcmp(daemon_service[i].name, name)) {
 407                        daemon_service[i].overridable = ena;
 408                        return;
 409                }
 410        }
 411        die("No such service %s", name);
 412}
 413
 414/*
 415 * Separate the "extra args" information as supplied by the client connection.
 416 * Any resulting data is squirreled away in the given interpolation table.
 417 */
 418static void parse_extra_args(struct interp *table, char *extra_args, int buflen)
 419{
 420        char *val;
 421        int vallen;
 422        char *end = extra_args + buflen;
 423
 424        while (extra_args < end && *extra_args) {
 425                saw_extended_args = 1;
 426                if (strncasecmp("host=", extra_args, 5) == 0) {
 427                        val = extra_args + 5;
 428                        vallen = strlen(val) + 1;
 429                        if (*val) {
 430                                /* Split <host>:<port> at colon. */
 431                                char *host = val;
 432                                char *port = strrchr(host, ':');
 433                                if (port) {
 434                                        *port = 0;
 435                                        port++;
 436                                        interp_set_entry(table, INTERP_SLOT_PORT, port);
 437                                }
 438                                interp_set_entry(table, INTERP_SLOT_HOST, host);
 439                        }
 440
 441                        /* On to the next one */
 442                        extra_args = val + vallen;
 443                }
 444        }
 445}
 446
 447static void fill_in_extra_table_entries(struct interp *itable)
 448{
 449        char *hp;
 450
 451        /*
 452         * Replace literal host with lowercase-ized hostname.
 453         */
 454        hp = interp_table[INTERP_SLOT_HOST].value;
 455        if (!hp)
 456                return;
 457        for ( ; *hp; hp++)
 458                *hp = tolower(*hp);
 459
 460        /*
 461         * Locate canonical hostname and its IP address.
 462         */
 463#ifndef NO_IPV6
 464        {
 465                struct addrinfo hints;
 466                struct addrinfo *ai, *ai0;
 467                int gai;
 468                static char addrbuf[HOST_NAME_MAX + 1];
 469
 470                memset(&hints, 0, sizeof(hints));
 471                hints.ai_flags = AI_CANONNAME;
 472
 473                gai = getaddrinfo(interp_table[INTERP_SLOT_HOST].value, 0, &hints, &ai0);
 474                if (!gai) {
 475                        for (ai = ai0; ai; ai = ai->ai_next) {
 476                                struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 477
 478                                inet_ntop(AF_INET, &sin_addr->sin_addr,
 479                                          addrbuf, sizeof(addrbuf));
 480                                interp_set_entry(interp_table,
 481                                                 INTERP_SLOT_CANON_HOST, ai->ai_canonname);
 482                                interp_set_entry(interp_table,
 483                                                 INTERP_SLOT_IP, addrbuf);
 484                                break;
 485                        }
 486                        freeaddrinfo(ai0);
 487                }
 488        }
 489#else
 490        {
 491                struct hostent *hent;
 492                struct sockaddr_in sa;
 493                char **ap;
 494                static char addrbuf[HOST_NAME_MAX + 1];
 495
 496                hent = gethostbyname(interp_table[INTERP_SLOT_HOST].value);
 497
 498                ap = hent->h_addr_list;
 499                memset(&sa, 0, sizeof sa);
 500                sa.sin_family = hent->h_addrtype;
 501                sa.sin_port = htons(0);
 502                memcpy(&sa.sin_addr, *ap, hent->h_length);
 503
 504                inet_ntop(hent->h_addrtype, &sa.sin_addr,
 505                          addrbuf, sizeof(addrbuf));
 506
 507                interp_set_entry(interp_table, INTERP_SLOT_CANON_HOST, hent->h_name);
 508                interp_set_entry(interp_table, INTERP_SLOT_IP, addrbuf);
 509        }
 510#endif
 511}
 512
 513
 514static int execute(struct sockaddr *addr)
 515{
 516        static char line[1000];
 517        int pktlen, len, i;
 518
 519        if (addr) {
 520                char addrbuf[256] = "";
 521                int port = -1;
 522
 523                if (addr->sa_family == AF_INET) {
 524                        struct sockaddr_in *sin_addr = (void *) addr;
 525                        inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
 526                        port = ntohs(sin_addr->sin_port);
 527#ifndef NO_IPV6
 528                } else if (addr && addr->sa_family == AF_INET6) {
 529                        struct sockaddr_in6 *sin6_addr = (void *) addr;
 530
 531                        char *buf = addrbuf;
 532                        *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 533                        inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
 534                        strcat(buf, "]");
 535
 536                        port = ntohs(sin6_addr->sin6_port);
 537#endif
 538                }
 539                loginfo("Connection from %s:%d", addrbuf, port);
 540        }
 541
 542        alarm(init_timeout ? init_timeout : timeout);
 543        pktlen = packet_read_line(0, line, sizeof(line));
 544        alarm(0);
 545
 546        len = strlen(line);
 547        if (pktlen != len)
 548                loginfo("Extended attributes (%d bytes) exist <%.*s>",
 549                        (int) pktlen - len,
 550                        (int) pktlen - len, line + len + 1);
 551        if (len && line[len-1] == '\n') {
 552                line[--len] = 0;
 553                pktlen--;
 554        }
 555
 556        /*
 557         * Initialize the path interpolation table for this connection.
 558         */
 559        interp_clear_table(interp_table, ARRAY_SIZE(interp_table));
 560        interp_set_entry(interp_table, INTERP_SLOT_PERCENT, "%");
 561
 562        if (len != pktlen) {
 563            parse_extra_args(interp_table, line + len + 1, pktlen - len - 1);
 564            fill_in_extra_table_entries(interp_table);
 565        }
 566
 567        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 568                struct daemon_service *s = &(daemon_service[i]);
 569                int namelen = strlen(s->name);
 570                if (!prefixcmp(line, "git-") &&
 571                    !strncmp(s->name, line + 4, namelen) &&
 572                    line[namelen + 4] == ' ') {
 573                        /*
 574                         * Note: The directory here is probably context sensitive,
 575                         * and might depend on the actual service being performed.
 576                         */
 577                        interp_set_entry(interp_table,
 578                                         INTERP_SLOT_DIR, line + namelen + 5);
 579                        return run_service(interp_table, s);
 580                }
 581        }
 582
 583        logerror("Protocol error: '%s'", line);
 584        return -1;
 585}
 586
 587static int max_connections = 32;
 588
 589static unsigned int live_children;
 590
 591static struct child {
 592        struct child *next;
 593        pid_t pid;
 594        struct sockaddr_storage address;
 595} *firstborn;
 596
 597static void add_child(pid_t pid, struct sockaddr *addr, int addrlen)
 598{
 599        struct child *newborn, **cradle;
 600
 601        /*
 602         * This must be xcalloc() -- we'll compare the whole sockaddr_storage
 603         * but individual address may be shorter.
 604         */
 605        newborn = xcalloc(1, sizeof(*newborn));
 606        live_children++;
 607        newborn->pid = pid;
 608        memcpy(&newborn->address, addr, addrlen);
 609        for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 610                if (!memcmp(&(*cradle)->address, &newborn->address,
 611                            sizeof(newborn->address)))
 612                        break;
 613        newborn->next = *cradle;
 614        *cradle = newborn;
 615}
 616
 617static void remove_child(pid_t pid)
 618{
 619        struct child **cradle, *blanket;
 620
 621        for (cradle = &firstborn; (blanket = *cradle); cradle = &blanket->next)
 622                if (blanket->pid == pid) {
 623                        *cradle = blanket->next;
 624                        live_children--;
 625                        free(blanket);
 626                        break;
 627                }
 628}
 629
 630/*
 631 * This gets called if the number of connections grows
 632 * past "max_connections".
 633 *
 634 * We kill the newest connection from a duplicate IP.
 635 */
 636static void kill_some_child(void)
 637{
 638        const struct child *blanket, *next;
 639
 640        if (!(blanket = firstborn))
 641                return;
 642
 643        for (; (next = blanket->next); blanket = next)
 644                if (!memcmp(&blanket->address, &next->address,
 645                            sizeof(next->address))) {
 646                        kill(blanket->pid, SIGTERM);
 647                        break;
 648                }
 649}
 650
 651static void check_dead_children(void)
 652{
 653        int status;
 654        pid_t pid;
 655
 656        while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
 657                const char *dead = "";
 658                remove_child(pid);
 659                if (!WIFEXITED(status) || (WEXITSTATUS(status) > 0))
 660                        dead = " (with error)";
 661                loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 662        }
 663}
 664
 665static void handle(int incoming, struct sockaddr *addr, int addrlen)
 666{
 667        pid_t pid;
 668
 669        if (max_connections && live_children >= max_connections) {
 670                kill_some_child();
 671                sleep(1);  /* give it some time to die */
 672                check_dead_children();
 673                if (live_children >= max_connections) {
 674                        close(incoming);
 675                        logerror("Too many children, dropping connection");
 676                        return;
 677                }
 678        }
 679
 680        if ((pid = fork())) {
 681                close(incoming);
 682                if (pid < 0) {
 683                        logerror("Couldn't fork %s", strerror(errno));
 684                        return;
 685                }
 686
 687                add_child(pid, addr, addrlen);
 688                return;
 689        }
 690
 691        dup2(incoming, 0);
 692        dup2(incoming, 1);
 693        close(incoming);
 694
 695        exit(execute(addr));
 696}
 697
 698static void child_handler(int signo)
 699{
 700        /*
 701         * Otherwise empty handler because systemcalls will get interrupted
 702         * upon signal receipt
 703         * SysV needs the handler to be rearmed
 704         */
 705        signal(SIGCHLD, child_handler);
 706}
 707
 708static int set_reuse_addr(int sockfd)
 709{
 710        int on = 1;
 711
 712        if (!reuseaddr)
 713                return 0;
 714        return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 715                          &on, sizeof(on));
 716}
 717
 718#ifndef NO_IPV6
 719
 720static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 721{
 722        int socknum = 0, *socklist = NULL;
 723        int maxfd = -1;
 724        char pbuf[NI_MAXSERV];
 725        struct addrinfo hints, *ai0, *ai;
 726        int gai;
 727        long flags;
 728
 729        sprintf(pbuf, "%d", listen_port);
 730        memset(&hints, 0, sizeof(hints));
 731        hints.ai_family = AF_UNSPEC;
 732        hints.ai_socktype = SOCK_STREAM;
 733        hints.ai_protocol = IPPROTO_TCP;
 734        hints.ai_flags = AI_PASSIVE;
 735
 736        gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 737        if (gai)
 738                die("getaddrinfo() failed: %s\n", gai_strerror(gai));
 739
 740        for (ai = ai0; ai; ai = ai->ai_next) {
 741                int sockfd;
 742
 743                sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 744                if (sockfd < 0)
 745                        continue;
 746                if (sockfd >= FD_SETSIZE) {
 747                        logerror("Socket descriptor too large");
 748                        close(sockfd);
 749                        continue;
 750                }
 751
 752#ifdef IPV6_V6ONLY
 753                if (ai->ai_family == AF_INET6) {
 754                        int on = 1;
 755                        setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 756                                   &on, sizeof(on));
 757                        /* Note: error is not fatal */
 758                }
 759#endif
 760
 761                if (set_reuse_addr(sockfd)) {
 762                        close(sockfd);
 763                        continue;
 764                }
 765
 766                if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 767                        close(sockfd);
 768                        continue;       /* not fatal */
 769                }
 770                if (listen(sockfd, 5) < 0) {
 771                        close(sockfd);
 772                        continue;       /* not fatal */
 773                }
 774
 775                flags = fcntl(sockfd, F_GETFD, 0);
 776                if (flags >= 0)
 777                        fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 778
 779                socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
 780                socklist[socknum++] = sockfd;
 781
 782                if (maxfd < sockfd)
 783                        maxfd = sockfd;
 784        }
 785
 786        freeaddrinfo(ai0);
 787
 788        *socklist_p = socklist;
 789        return socknum;
 790}
 791
 792#else /* NO_IPV6 */
 793
 794static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 795{
 796        struct sockaddr_in sin;
 797        int sockfd;
 798        long flags;
 799
 800        memset(&sin, 0, sizeof sin);
 801        sin.sin_family = AF_INET;
 802        sin.sin_port = htons(listen_port);
 803
 804        if (listen_addr) {
 805                /* Well, host better be an IP address here. */
 806                if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 807                        return 0;
 808        } else {
 809                sin.sin_addr.s_addr = htonl(INADDR_ANY);
 810        }
 811
 812        sockfd = socket(AF_INET, SOCK_STREAM, 0);
 813        if (sockfd < 0)
 814                return 0;
 815
 816        if (set_reuse_addr(sockfd)) {
 817                close(sockfd);
 818                return 0;
 819        }
 820
 821        if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 822                close(sockfd);
 823                return 0;
 824        }
 825
 826        if (listen(sockfd, 5) < 0) {
 827                close(sockfd);
 828                return 0;
 829        }
 830
 831        flags = fcntl(sockfd, F_GETFD, 0);
 832        if (flags >= 0)
 833                fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 834
 835        *socklist_p = xmalloc(sizeof(int));
 836        **socklist_p = sockfd;
 837        return 1;
 838}
 839
 840#endif
 841
 842static int service_loop(int socknum, int *socklist)
 843{
 844        struct pollfd *pfd;
 845        int i;
 846
 847        pfd = xcalloc(socknum, sizeof(struct pollfd));
 848
 849        for (i = 0; i < socknum; i++) {
 850                pfd[i].fd = socklist[i];
 851                pfd[i].events = POLLIN;
 852        }
 853
 854        signal(SIGCHLD, child_handler);
 855
 856        for (;;) {
 857                int i;
 858
 859                check_dead_children();
 860
 861                if (poll(pfd, socknum, -1) < 0) {
 862                        if (errno != EINTR) {
 863                                logerror("Poll failed, resuming: %s",
 864                                      strerror(errno));
 865                                sleep(1);
 866                        }
 867                        continue;
 868                }
 869
 870                for (i = 0; i < socknum; i++) {
 871                        if (pfd[i].revents & POLLIN) {
 872                                struct sockaddr_storage ss;
 873                                unsigned int sslen = sizeof(ss);
 874                                int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
 875                                if (incoming < 0) {
 876                                        switch (errno) {
 877                                        case EAGAIN:
 878                                        case EINTR:
 879                                        case ECONNABORTED:
 880                                                continue;
 881                                        default:
 882                                                die("accept returned %s", strerror(errno));
 883                                        }
 884                                }
 885                                handle(incoming, (struct sockaddr *)&ss, sslen);
 886                        }
 887                }
 888        }
 889}
 890
 891/* if any standard file descriptor is missing open it to /dev/null */
 892static void sanitize_stdfds(void)
 893{
 894        int fd = open("/dev/null", O_RDWR, 0);
 895        while (fd != -1 && fd < 2)
 896                fd = dup(fd);
 897        if (fd == -1)
 898                die("open /dev/null or dup failed: %s", strerror(errno));
 899        if (fd > 2)
 900                close(fd);
 901}
 902
 903static void daemonize(void)
 904{
 905        switch (fork()) {
 906                case 0:
 907                        break;
 908                case -1:
 909                        die("fork failed: %s", strerror(errno));
 910                default:
 911                        exit(0);
 912        }
 913        if (setsid() == -1)
 914                die("setsid failed: %s", strerror(errno));
 915        close(0);
 916        close(1);
 917        close(2);
 918        sanitize_stdfds();
 919}
 920
 921static void store_pid(const char *path)
 922{
 923        FILE *f = fopen(path, "w");
 924        if (!f)
 925                die("cannot open pid file %s: %s", path, strerror(errno));
 926        if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
 927                die("failed to write pid file %s: %s", path, strerror(errno));
 928}
 929
 930static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
 931{
 932        int socknum, *socklist;
 933
 934        socknum = socksetup(listen_addr, listen_port, &socklist);
 935        if (socknum == 0)
 936                die("unable to allocate any listen sockets on host %s port %u",
 937                    listen_addr, listen_port);
 938
 939        if (pass && gid &&
 940            (initgroups(pass->pw_name, gid) || setgid (gid) ||
 941             setuid(pass->pw_uid)))
 942                die("cannot drop privileges");
 943
 944        return service_loop(socknum, socklist);
 945}
 946
 947int main(int argc, char **argv)
 948{
 949        int listen_port = 0;
 950        char *listen_addr = NULL;
 951        int inetd_mode = 0;
 952        const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
 953        int detach = 0;
 954        struct passwd *pass = NULL;
 955        struct group *group;
 956        gid_t gid = 0;
 957        int i;
 958
 959        for (i = 1; i < argc; i++) {
 960                char *arg = argv[i];
 961
 962                if (!prefixcmp(arg, "--listen=")) {
 963                    char *p = arg + 9;
 964                    char *ph = listen_addr = xmalloc(strlen(arg + 9) + 1);
 965                    while (*p)
 966                        *ph++ = tolower(*p++);
 967                    *ph = 0;
 968                    continue;
 969                }
 970                if (!prefixcmp(arg, "--port=")) {
 971                        char *end;
 972                        unsigned long n;
 973                        n = strtoul(arg+7, &end, 0);
 974                        if (arg[7] && !*end) {
 975                                listen_port = n;
 976                                continue;
 977                        }
 978                }
 979                if (!strcmp(arg, "--inetd")) {
 980                        inetd_mode = 1;
 981                        log_syslog = 1;
 982                        continue;
 983                }
 984                if (!strcmp(arg, "--verbose")) {
 985                        verbose = 1;
 986                        continue;
 987                }
 988                if (!strcmp(arg, "--syslog")) {
 989                        log_syslog = 1;
 990                        continue;
 991                }
 992                if (!strcmp(arg, "--export-all")) {
 993                        export_all_trees = 1;
 994                        continue;
 995                }
 996                if (!prefixcmp(arg, "--timeout=")) {
 997                        timeout = atoi(arg+10);
 998                        continue;
 999                }
1000                if (!prefixcmp(arg, "--init-timeout=")) {
1001                        init_timeout = atoi(arg+15);
1002                        continue;
1003                }
1004                if (!prefixcmp(arg, "--max-connections=")) {
1005                        max_connections = atoi(arg+18);
1006                        if (max_connections < 0)
1007                                max_connections = 0;            /* unlimited */
1008                        continue;
1009                }
1010                if (!strcmp(arg, "--strict-paths")) {
1011                        strict_paths = 1;
1012                        continue;
1013                }
1014                if (!prefixcmp(arg, "--base-path=")) {
1015                        base_path = arg+12;
1016                        continue;
1017                }
1018                if (!strcmp(arg, "--base-path-relaxed")) {
1019                        base_path_relaxed = 1;
1020                        continue;
1021                }
1022                if (!prefixcmp(arg, "--interpolated-path=")) {
1023                        interpolated_path = arg+20;
1024                        continue;
1025                }
1026                if (!strcmp(arg, "--reuseaddr")) {
1027                        reuseaddr = 1;
1028                        continue;
1029                }
1030                if (!strcmp(arg, "--user-path")) {
1031                        user_path = "";
1032                        continue;
1033                }
1034                if (!prefixcmp(arg, "--user-path=")) {
1035                        user_path = arg + 12;
1036                        continue;
1037                }
1038                if (!prefixcmp(arg, "--pid-file=")) {
1039                        pid_file = arg + 11;
1040                        continue;
1041                }
1042                if (!strcmp(arg, "--detach")) {
1043                        detach = 1;
1044                        log_syslog = 1;
1045                        continue;
1046                }
1047                if (!prefixcmp(arg, "--user=")) {
1048                        user_name = arg + 7;
1049                        continue;
1050                }
1051                if (!prefixcmp(arg, "--group=")) {
1052                        group_name = arg + 8;
1053                        continue;
1054                }
1055                if (!prefixcmp(arg, "--enable=")) {
1056                        enable_service(arg + 9, 1);
1057                        continue;
1058                }
1059                if (!prefixcmp(arg, "--disable=")) {
1060                        enable_service(arg + 10, 0);
1061                        continue;
1062                }
1063                if (!prefixcmp(arg, "--allow-override=")) {
1064                        make_service_overridable(arg + 17, 1);
1065                        continue;
1066                }
1067                if (!prefixcmp(arg, "--forbid-override=")) {
1068                        make_service_overridable(arg + 18, 0);
1069                        continue;
1070                }
1071                if (!strcmp(arg, "--")) {
1072                        ok_paths = &argv[i+1];
1073                        break;
1074                } else if (arg[0] != '-') {
1075                        ok_paths = &argv[i];
1076                        break;
1077                }
1078
1079                usage(daemon_usage);
1080        }
1081
1082        if (log_syslog) {
1083                openlog("git-daemon", LOG_PID, LOG_DAEMON);
1084                set_die_routine(daemon_die);
1085        } else
1086                setlinebuf(stderr); /* avoid splitting a message in the middle */
1087
1088        if (inetd_mode && (group_name || user_name))
1089                die("--user and --group are incompatible with --inetd");
1090
1091        if (inetd_mode && (listen_port || listen_addr))
1092                die("--listen= and --port= are incompatible with --inetd");
1093        else if (listen_port == 0)
1094                listen_port = DEFAULT_GIT_PORT;
1095
1096        if (group_name && !user_name)
1097                die("--group supplied without --user");
1098
1099        if (user_name) {
1100                pass = getpwnam(user_name);
1101                if (!pass)
1102                        die("user not found - %s", user_name);
1103
1104                if (!group_name)
1105                        gid = pass->pw_gid;
1106                else {
1107                        group = getgrnam(group_name);
1108                        if (!group)
1109                                die("group not found - %s", group_name);
1110
1111                        gid = group->gr_gid;
1112                }
1113        }
1114
1115        if (strict_paths && (!ok_paths || !*ok_paths))
1116                die("option --strict-paths requires a whitelist");
1117
1118        if (base_path) {
1119                struct stat st;
1120
1121                if (stat(base_path, &st) || !S_ISDIR(st.st_mode))
1122                        die("base-path '%s' does not exist or "
1123                            "is not a directory", base_path);
1124        }
1125
1126        if (inetd_mode) {
1127                struct sockaddr_storage ss;
1128                struct sockaddr *peer = (struct sockaddr *)&ss;
1129                socklen_t slen = sizeof(ss);
1130
1131                freopen("/dev/null", "w", stderr);
1132
1133                if (getpeername(0, peer, &slen))
1134                        peer = NULL;
1135
1136                return execute(peer);
1137        }
1138
1139        if (detach) {
1140                daemonize();
1141                loginfo("Ready to rumble");
1142        }
1143        else
1144                sanitize_stdfds();
1145
1146        if (pid_file)
1147                store_pid(pid_file);
1148
1149        return serve(listen_addr, listen_port, pass, gid);
1150}