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