Andrew's git / gitweb.git / daemon.c
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daemon.con commit mergetool: Add prompt to continue after failing to merge a file (b0169d8)
   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                setenv("REMOTE_ADDR", addrbuf, 1);
 541        }
 542        else {
 543                unsetenv("REMOTE_ADDR");
 544        }
 545
 546        alarm(init_timeout ? init_timeout : timeout);
 547        pktlen = packet_read_line(0, line, sizeof(line));
 548        alarm(0);
 549
 550        len = strlen(line);
 551        if (pktlen != len)
 552                loginfo("Extended attributes (%d bytes) exist <%.*s>",
 553                        (int) pktlen - len,
 554                        (int) pktlen - len, line + len + 1);
 555        if (len && line[len-1] == '\n') {
 556                line[--len] = 0;
 557                pktlen--;
 558        }
 559
 560        /*
 561         * Initialize the path interpolation table for this connection.
 562         */
 563        interp_clear_table(interp_table, ARRAY_SIZE(interp_table));
 564        interp_set_entry(interp_table, INTERP_SLOT_PERCENT, "%");
 565
 566        if (len != pktlen) {
 567            parse_extra_args(interp_table, line + len + 1, pktlen - len - 1);
 568            fill_in_extra_table_entries(interp_table);
 569        }
 570
 571        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 572                struct daemon_service *s = &(daemon_service[i]);
 573                int namelen = strlen(s->name);
 574                if (!prefixcmp(line, "git-") &&
 575                    !strncmp(s->name, line + 4, namelen) &&
 576                    line[namelen + 4] == ' ') {
 577                        /*
 578                         * Note: The directory here is probably context sensitive,
 579                         * and might depend on the actual service being performed.
 580                         */
 581                        interp_set_entry(interp_table,
 582                                         INTERP_SLOT_DIR, line + namelen + 5);
 583                        return run_service(interp_table, s);
 584                }
 585        }
 586
 587        logerror("Protocol error: '%s'", line);
 588        return -1;
 589}
 590
 591static int max_connections = 32;
 592
 593static unsigned int live_children;
 594
 595static struct child {
 596        struct child *next;
 597        pid_t pid;
 598        struct sockaddr_storage address;
 599} *firstborn;
 600
 601static void add_child(pid_t pid, struct sockaddr *addr, int addrlen)
 602{
 603        struct child *newborn, **cradle;
 604
 605        /*
 606         * This must be xcalloc() -- we'll compare the whole sockaddr_storage
 607         * but individual address may be shorter.
 608         */
 609        newborn = xcalloc(1, sizeof(*newborn));
 610        live_children++;
 611        newborn->pid = pid;
 612        memcpy(&newborn->address, addr, addrlen);
 613        for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 614                if (!memcmp(&(*cradle)->address, &newborn->address,
 615                            sizeof(newborn->address)))
 616                        break;
 617        newborn->next = *cradle;
 618        *cradle = newborn;
 619}
 620
 621static void remove_child(pid_t pid)
 622{
 623        struct child **cradle, *blanket;
 624
 625        for (cradle = &firstborn; (blanket = *cradle); cradle = &blanket->next)
 626                if (blanket->pid == pid) {
 627                        *cradle = blanket->next;
 628                        live_children--;
 629                        free(blanket);
 630                        break;
 631                }
 632}
 633
 634/*
 635 * This gets called if the number of connections grows
 636 * past "max_connections".
 637 *
 638 * We kill the newest connection from a duplicate IP.
 639 */
 640static void kill_some_child(void)
 641{
 642        const struct child *blanket, *next;
 643
 644        if (!(blanket = firstborn))
 645                return;
 646
 647        for (; (next = blanket->next); blanket = next)
 648                if (!memcmp(&blanket->address, &next->address,
 649                            sizeof(next->address))) {
 650                        kill(blanket->pid, SIGTERM);
 651                        break;
 652                }
 653}
 654
 655static void check_dead_children(void)
 656{
 657        int status;
 658        pid_t pid;
 659
 660        while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
 661                const char *dead = "";
 662                remove_child(pid);
 663                if (!WIFEXITED(status) || (WEXITSTATUS(status) > 0))
 664                        dead = " (with error)";
 665                loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 666        }
 667}
 668
 669static void handle(int incoming, struct sockaddr *addr, int addrlen)
 670{
 671        pid_t pid;
 672
 673        if (max_connections && live_children >= max_connections) {
 674                kill_some_child();
 675                sleep(1);  /* give it some time to die */
 676                check_dead_children();
 677                if (live_children >= max_connections) {
 678                        close(incoming);
 679                        logerror("Too many children, dropping connection");
 680                        return;
 681                }
 682        }
 683
 684        if ((pid = fork())) {
 685                close(incoming);
 686                if (pid < 0) {
 687                        logerror("Couldn't fork %s", strerror(errno));
 688                        return;
 689                }
 690
 691                add_child(pid, addr, addrlen);
 692                return;
 693        }
 694
 695        dup2(incoming, 0);
 696        dup2(incoming, 1);
 697        close(incoming);
 698
 699        exit(execute(addr));
 700}
 701
 702static void child_handler(int signo)
 703{
 704        /*
 705         * Otherwise empty handler because systemcalls will get interrupted
 706         * upon signal receipt
 707         * SysV needs the handler to be rearmed
 708         */
 709        signal(SIGCHLD, child_handler);
 710}
 711
 712static int set_reuse_addr(int sockfd)
 713{
 714        int on = 1;
 715
 716        if (!reuseaddr)
 717                return 0;
 718        return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 719                          &on, sizeof(on));
 720}
 721
 722#ifndef NO_IPV6
 723
 724static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 725{
 726        int socknum = 0, *socklist = NULL;
 727        int maxfd = -1;
 728        char pbuf[NI_MAXSERV];
 729        struct addrinfo hints, *ai0, *ai;
 730        int gai;
 731        long flags;
 732
 733        sprintf(pbuf, "%d", listen_port);
 734        memset(&hints, 0, sizeof(hints));
 735        hints.ai_family = AF_UNSPEC;
 736        hints.ai_socktype = SOCK_STREAM;
 737        hints.ai_protocol = IPPROTO_TCP;
 738        hints.ai_flags = AI_PASSIVE;
 739
 740        gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 741        if (gai)
 742                die("getaddrinfo() failed: %s\n", gai_strerror(gai));
 743
 744        for (ai = ai0; ai; ai = ai->ai_next) {
 745                int sockfd;
 746
 747                sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 748                if (sockfd < 0)
 749                        continue;
 750                if (sockfd >= FD_SETSIZE) {
 751                        logerror("Socket descriptor too large");
 752                        close(sockfd);
 753                        continue;
 754                }
 755
 756#ifdef IPV6_V6ONLY
 757                if (ai->ai_family == AF_INET6) {
 758                        int on = 1;
 759                        setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 760                                   &on, sizeof(on));
 761                        /* Note: error is not fatal */
 762                }
 763#endif
 764
 765                if (set_reuse_addr(sockfd)) {
 766                        close(sockfd);
 767                        continue;
 768                }
 769
 770                if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 771                        close(sockfd);
 772                        continue;       /* not fatal */
 773                }
 774                if (listen(sockfd, 5) < 0) {
 775                        close(sockfd);
 776                        continue;       /* not fatal */
 777                }
 778
 779                flags = fcntl(sockfd, F_GETFD, 0);
 780                if (flags >= 0)
 781                        fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 782
 783                socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
 784                socklist[socknum++] = sockfd;
 785
 786                if (maxfd < sockfd)
 787                        maxfd = sockfd;
 788        }
 789
 790        freeaddrinfo(ai0);
 791
 792        *socklist_p = socklist;
 793        return socknum;
 794}
 795
 796#else /* NO_IPV6 */
 797
 798static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 799{
 800        struct sockaddr_in sin;
 801        int sockfd;
 802        long flags;
 803
 804        memset(&sin, 0, sizeof sin);
 805        sin.sin_family = AF_INET;
 806        sin.sin_port = htons(listen_port);
 807
 808        if (listen_addr) {
 809                /* Well, host better be an IP address here. */
 810                if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 811                        return 0;
 812        } else {
 813                sin.sin_addr.s_addr = htonl(INADDR_ANY);
 814        }
 815
 816        sockfd = socket(AF_INET, SOCK_STREAM, 0);
 817        if (sockfd < 0)
 818                return 0;
 819
 820        if (set_reuse_addr(sockfd)) {
 821                close(sockfd);
 822                return 0;
 823        }
 824
 825        if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 826                close(sockfd);
 827                return 0;
 828        }
 829
 830        if (listen(sockfd, 5) < 0) {
 831                close(sockfd);
 832                return 0;
 833        }
 834
 835        flags = fcntl(sockfd, F_GETFD, 0);
 836        if (flags >= 0)
 837                fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 838
 839        *socklist_p = xmalloc(sizeof(int));
 840        **socklist_p = sockfd;
 841        return 1;
 842}
 843
 844#endif
 845
 846static int service_loop(int socknum, int *socklist)
 847{
 848        struct pollfd *pfd;
 849        int i;
 850
 851        pfd = xcalloc(socknum, sizeof(struct pollfd));
 852
 853        for (i = 0; i < socknum; i++) {
 854                pfd[i].fd = socklist[i];
 855                pfd[i].events = POLLIN;
 856        }
 857
 858        signal(SIGCHLD, child_handler);
 859
 860        for (;;) {
 861                int i;
 862
 863                check_dead_children();
 864
 865                if (poll(pfd, socknum, -1) < 0) {
 866                        if (errno != EINTR) {
 867                                logerror("Poll failed, resuming: %s",
 868                                      strerror(errno));
 869                                sleep(1);
 870                        }
 871                        continue;
 872                }
 873
 874                for (i = 0; i < socknum; i++) {
 875                        if (pfd[i].revents & POLLIN) {
 876                                struct sockaddr_storage ss;
 877                                unsigned int sslen = sizeof(ss);
 878                                int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
 879                                if (incoming < 0) {
 880                                        switch (errno) {
 881                                        case EAGAIN:
 882                                        case EINTR:
 883                                        case ECONNABORTED:
 884                                                continue;
 885                                        default:
 886                                                die("accept returned %s", strerror(errno));
 887                                        }
 888                                }
 889                                handle(incoming, (struct sockaddr *)&ss, sslen);
 890                        }
 891                }
 892        }
 893}
 894
 895/* if any standard file descriptor is missing open it to /dev/null */
 896static void sanitize_stdfds(void)
 897{
 898        int fd = open("/dev/null", O_RDWR, 0);
 899        while (fd != -1 && fd < 2)
 900                fd = dup(fd);
 901        if (fd == -1)
 902                die("open /dev/null or dup failed: %s", strerror(errno));
 903        if (fd > 2)
 904                close(fd);
 905}
 906
 907static void daemonize(void)
 908{
 909        switch (fork()) {
 910                case 0:
 911                        break;
 912                case -1:
 913                        die("fork failed: %s", strerror(errno));
 914                default:
 915                        exit(0);
 916        }
 917        if (setsid() == -1)
 918                die("setsid failed: %s", strerror(errno));
 919        close(0);
 920        close(1);
 921        close(2);
 922        sanitize_stdfds();
 923}
 924
 925static void store_pid(const char *path)
 926{
 927        FILE *f = fopen(path, "w");
 928        if (!f)
 929                die("cannot open pid file %s: %s", path, strerror(errno));
 930        if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
 931                die("failed to write pid file %s: %s", path, strerror(errno));
 932}
 933
 934static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
 935{
 936        int socknum, *socklist;
 937
 938        socknum = socksetup(listen_addr, listen_port, &socklist);
 939        if (socknum == 0)
 940                die("unable to allocate any listen sockets on host %s port %u",
 941                    listen_addr, listen_port);
 942
 943        if (pass && gid &&
 944            (initgroups(pass->pw_name, gid) || setgid (gid) ||
 945             setuid(pass->pw_uid)))
 946                die("cannot drop privileges");
 947
 948        return service_loop(socknum, socklist);
 949}
 950
 951int main(int argc, char **argv)
 952{
 953        int listen_port = 0;
 954        char *listen_addr = NULL;
 955        int inetd_mode = 0;
 956        const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
 957        int detach = 0;
 958        struct passwd *pass = NULL;
 959        struct group *group;
 960        gid_t gid = 0;
 961        int i;
 962
 963        for (i = 1; i < argc; i++) {
 964                char *arg = argv[i];
 965
 966                if (!prefixcmp(arg, "--listen=")) {
 967                    char *p = arg + 9;
 968                    char *ph = listen_addr = xmalloc(strlen(arg + 9) + 1);
 969                    while (*p)
 970                        *ph++ = tolower(*p++);
 971                    *ph = 0;
 972                    continue;
 973                }
 974                if (!prefixcmp(arg, "--port=")) {
 975                        char *end;
 976                        unsigned long n;
 977                        n = strtoul(arg+7, &end, 0);
 978                        if (arg[7] && !*end) {
 979                                listen_port = n;
 980                                continue;
 981                        }
 982                }
 983                if (!strcmp(arg, "--inetd")) {
 984                        inetd_mode = 1;
 985                        log_syslog = 1;
 986                        continue;
 987                }
 988                if (!strcmp(arg, "--verbose")) {
 989                        verbose = 1;
 990                        continue;
 991                }
 992                if (!strcmp(arg, "--syslog")) {
 993                        log_syslog = 1;
 994                        continue;
 995                }
 996                if (!strcmp(arg, "--export-all")) {
 997                        export_all_trees = 1;
 998                        continue;
 999                }
1000                if (!prefixcmp(arg, "--timeout=")) {
1001                        timeout = atoi(arg+10);
1002                        continue;
1003                }
1004                if (!prefixcmp(arg, "--init-timeout=")) {
1005                        init_timeout = atoi(arg+15);
1006                        continue;
1007                }
1008                if (!prefixcmp(arg, "--max-connections=")) {
1009                        max_connections = atoi(arg+18);
1010                        if (max_connections < 0)
1011                                max_connections = 0;            /* unlimited */
1012                        continue;
1013                }
1014                if (!strcmp(arg, "--strict-paths")) {
1015                        strict_paths = 1;
1016                        continue;
1017                }
1018                if (!prefixcmp(arg, "--base-path=")) {
1019                        base_path = arg+12;
1020                        continue;
1021                }
1022                if (!strcmp(arg, "--base-path-relaxed")) {
1023                        base_path_relaxed = 1;
1024                        continue;
1025                }
1026                if (!prefixcmp(arg, "--interpolated-path=")) {
1027                        interpolated_path = arg+20;
1028                        continue;
1029                }
1030                if (!strcmp(arg, "--reuseaddr")) {
1031                        reuseaddr = 1;
1032                        continue;
1033                }
1034                if (!strcmp(arg, "--user-path")) {
1035                        user_path = "";
1036                        continue;
1037                }
1038                if (!prefixcmp(arg, "--user-path=")) {
1039                        user_path = arg + 12;
1040                        continue;
1041                }
1042                if (!prefixcmp(arg, "--pid-file=")) {
1043                        pid_file = arg + 11;
1044                        continue;
1045                }
1046                if (!strcmp(arg, "--detach")) {
1047                        detach = 1;
1048                        log_syslog = 1;
1049                        continue;
1050                }
1051                if (!prefixcmp(arg, "--user=")) {
1052                        user_name = arg + 7;
1053                        continue;
1054                }
1055                if (!prefixcmp(arg, "--group=")) {
1056                        group_name = arg + 8;
1057                        continue;
1058                }
1059                if (!prefixcmp(arg, "--enable=")) {
1060                        enable_service(arg + 9, 1);
1061                        continue;
1062                }
1063                if (!prefixcmp(arg, "--disable=")) {
1064                        enable_service(arg + 10, 0);
1065                        continue;
1066                }
1067                if (!prefixcmp(arg, "--allow-override=")) {
1068                        make_service_overridable(arg + 17, 1);
1069                        continue;
1070                }
1071                if (!prefixcmp(arg, "--forbid-override=")) {
1072                        make_service_overridable(arg + 18, 0);
1073                        continue;
1074                }
1075                if (!strcmp(arg, "--")) {
1076                        ok_paths = &argv[i+1];
1077                        break;
1078                } else if (arg[0] != '-') {
1079                        ok_paths = &argv[i];
1080                        break;
1081                }
1082
1083                usage(daemon_usage);
1084        }
1085
1086        if (log_syslog) {
1087                openlog("git-daemon", LOG_PID, LOG_DAEMON);
1088                set_die_routine(daemon_die);
1089        } else
1090                /* avoid splitting a message in the middle */
1091                setvbuf(stderr, NULL, _IOLBF, 0);
1092
1093        if (inetd_mode && (group_name || user_name))
1094                die("--user and --group are incompatible with --inetd");
1095
1096        if (inetd_mode && (listen_port || listen_addr))
1097                die("--listen= and --port= are incompatible with --inetd");
1098        else if (listen_port == 0)
1099                listen_port = DEFAULT_GIT_PORT;
1100
1101        if (group_name && !user_name)
1102                die("--group supplied without --user");
1103
1104        if (user_name) {
1105                pass = getpwnam(user_name);
1106                if (!pass)
1107                        die("user not found - %s", user_name);
1108
1109                if (!group_name)
1110                        gid = pass->pw_gid;
1111                else {
1112                        group = getgrnam(group_name);
1113                        if (!group)
1114                                die("group not found - %s", group_name);
1115
1116                        gid = group->gr_gid;
1117                }
1118        }
1119
1120        if (strict_paths && (!ok_paths || !*ok_paths))
1121                die("option --strict-paths requires a whitelist");
1122
1123        if (base_path && !is_directory(base_path))
1124                die("base-path '%s' does not exist or is not a directory",
1125                    base_path);
1126
1127        if (inetd_mode) {
1128                struct sockaddr_storage ss;
1129                struct sockaddr *peer = (struct sockaddr *)&ss;
1130                socklen_t slen = sizeof(ss);
1131
1132                freopen("/dev/null", "w", stderr);
1133
1134                if (getpeername(0, peer, &slen))
1135                        peer = NULL;
1136
1137                return execute(peer);
1138        }
1139
1140        if (detach) {
1141                daemonize();
1142                loginfo("Ready to rumble");
1143        }
1144        else
1145                sanitize_stdfds();
1146
1147        if (pid_file)
1148                store_pid(pid_file);
1149
1150        return serve(listen_addr, listen_port, pass, gid);
1151}