Andrew's git / gitweb.git / daemon.c
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daemon.con commit replace: add test for --graft (adf8e54)
   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 (starts_with(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 void parse_host_and_port(char *hostport, char **host,
 479        char **port)
 480{
 481        if (*hostport == '[') {
 482                char *end;
 483
 484                end = strchr(hostport, ']');
 485                if (!end)
 486                        die("Invalid request ('[' without ']')");
 487                *end = '\0';
 488                *host = hostport + 1;
 489                if (!end[1])
 490                        *port = NULL;
 491                else if (end[1] == ':')
 492                        *port = end + 2;
 493                else
 494                        die("Garbage after end of host part");
 495        } else {
 496                *host = hostport;
 497                *port = strrchr(hostport, ':');
 498                if (*port) {
 499                        **port = '\0';
 500                        ++*port;
 501                }
 502        }
 503}
 504
 505/*
 506 * Read the host as supplied by the client connection.
 507 */
 508static void parse_host_arg(char *extra_args, int buflen)
 509{
 510        char *val;
 511        int vallen;
 512        char *end = extra_args + buflen;
 513
 514        if (extra_args < end && *extra_args) {
 515                saw_extended_args = 1;
 516                if (strncasecmp("host=", extra_args, 5) == 0) {
 517                        val = extra_args + 5;
 518                        vallen = strlen(val) + 1;
 519                        if (*val) {
 520                                /* Split <host>:<port> at colon. */
 521                                char *host;
 522                                char *port;
 523                                parse_host_and_port(val, &host, &port);
 524                                if (port) {
 525                                        free(tcp_port);
 526                                        tcp_port = xstrdup(port);
 527                                }
 528                                free(hostname);
 529                                hostname = xstrdup_tolower(host);
 530                        }
 531
 532                        /* On to the next one */
 533                        extra_args = val + vallen;
 534                }
 535                if (extra_args < end && *extra_args)
 536                        die("Invalid request");
 537        }
 538
 539        /*
 540         * Locate canonical hostname and its IP address.
 541         */
 542        if (hostname) {
 543#ifndef NO_IPV6
 544                struct addrinfo hints;
 545                struct addrinfo *ai;
 546                int gai;
 547                static char addrbuf[HOST_NAME_MAX + 1];
 548
 549                memset(&hints, 0, sizeof(hints));
 550                hints.ai_flags = AI_CANONNAME;
 551
 552                gai = getaddrinfo(hostname, NULL, &hints, &ai);
 553                if (!gai) {
 554                        struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 555
 556                        inet_ntop(AF_INET, &sin_addr->sin_addr,
 557                                  addrbuf, sizeof(addrbuf));
 558                        free(ip_address);
 559                        ip_address = xstrdup(addrbuf);
 560
 561                        free(canon_hostname);
 562                        canon_hostname = xstrdup(ai->ai_canonname ?
 563                                                 ai->ai_canonname : ip_address);
 564
 565                        freeaddrinfo(ai);
 566                }
 567#else
 568                struct hostent *hent;
 569                struct sockaddr_in sa;
 570                char **ap;
 571                static char addrbuf[HOST_NAME_MAX + 1];
 572
 573                hent = gethostbyname(hostname);
 574
 575                ap = hent->h_addr_list;
 576                memset(&sa, 0, sizeof sa);
 577                sa.sin_family = hent->h_addrtype;
 578                sa.sin_port = htons(0);
 579                memcpy(&sa.sin_addr, *ap, hent->h_length);
 580
 581                inet_ntop(hent->h_addrtype, &sa.sin_addr,
 582                          addrbuf, sizeof(addrbuf));
 583
 584                free(canon_hostname);
 585                canon_hostname = xstrdup(hent->h_name);
 586                free(ip_address);
 587                ip_address = xstrdup(addrbuf);
 588#endif
 589        }
 590}
 591
 592
 593static int execute(void)
 594{
 595        char *line = packet_buffer;
 596        int pktlen, len, i;
 597        char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
 598
 599        if (addr)
 600                loginfo("Connection from %s:%s", addr, port);
 601
 602        alarm(init_timeout ? init_timeout : timeout);
 603        pktlen = packet_read(0, NULL, NULL, packet_buffer, sizeof(packet_buffer), 0);
 604        alarm(0);
 605
 606        len = strlen(line);
 607        if (pktlen != len)
 608                loginfo("Extended attributes (%d bytes) exist <%.*s>",
 609                        (int) pktlen - len,
 610                        (int) pktlen - len, line + len + 1);
 611        if (len && line[len-1] == '\n') {
 612                line[--len] = 0;
 613                pktlen--;
 614        }
 615
 616        free(hostname);
 617        free(canon_hostname);
 618        free(ip_address);
 619        free(tcp_port);
 620        hostname = canon_hostname = ip_address = tcp_port = NULL;
 621
 622        if (len != pktlen)
 623                parse_host_arg(line + len + 1, pktlen - len - 1);
 624
 625        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 626                struct daemon_service *s = &(daemon_service[i]);
 627                int namelen = strlen(s->name);
 628                if (starts_with(line, "git-") &&
 629                    !strncmp(s->name, line + 4, namelen) &&
 630                    line[namelen + 4] == ' ') {
 631                        /*
 632                         * Note: The directory here is probably context sensitive,
 633                         * and might depend on the actual service being performed.
 634                         */
 635                        return run_service(line + namelen + 5, s);
 636                }
 637        }
 638
 639        logerror("Protocol error: '%s'", line);
 640        return -1;
 641}
 642
 643static int addrcmp(const struct sockaddr_storage *s1,
 644    const struct sockaddr_storage *s2)
 645{
 646        const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 647        const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 648
 649        if (sa1->sa_family != sa2->sa_family)
 650                return sa1->sa_family - sa2->sa_family;
 651        if (sa1->sa_family == AF_INET)
 652                return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 653                    &((struct sockaddr_in *)s2)->sin_addr,
 654                    sizeof(struct in_addr));
 655#ifndef NO_IPV6
 656        if (sa1->sa_family == AF_INET6)
 657                return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 658                    &((struct sockaddr_in6 *)s2)->sin6_addr,
 659                    sizeof(struct in6_addr));
 660#endif
 661        return 0;
 662}
 663
 664static int max_connections = 32;
 665
 666static unsigned int live_children;
 667
 668static struct child {
 669        struct child *next;
 670        struct child_process cld;
 671        struct sockaddr_storage address;
 672} *firstborn;
 673
 674static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
 675{
 676        struct child *newborn, **cradle;
 677
 678        newborn = xcalloc(1, sizeof(*newborn));
 679        live_children++;
 680        memcpy(&newborn->cld, cld, sizeof(*cld));
 681        memcpy(&newborn->address, addr, addrlen);
 682        for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 683                if (!addrcmp(&(*cradle)->address, &newborn->address))
 684                        break;
 685        newborn->next = *cradle;
 686        *cradle = newborn;
 687}
 688
 689/*
 690 * This gets called if the number of connections grows
 691 * past "max_connections".
 692 *
 693 * We kill the newest connection from a duplicate IP.
 694 */
 695static void kill_some_child(void)
 696{
 697        const struct child *blanket, *next;
 698
 699        if (!(blanket = firstborn))
 700                return;
 701
 702        for (; (next = blanket->next); blanket = next)
 703                if (!addrcmp(&blanket->address, &next->address)) {
 704                        kill(blanket->cld.pid, SIGTERM);
 705                        break;
 706                }
 707}
 708
 709static void check_dead_children(void)
 710{
 711        int status;
 712        pid_t pid;
 713
 714        struct child **cradle, *blanket;
 715        for (cradle = &firstborn; (blanket = *cradle);)
 716                if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
 717                        const char *dead = "";
 718                        if (status)
 719                                dead = " (with error)";
 720                        loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 721
 722                        /* remove the child */
 723                        *cradle = blanket->next;
 724                        live_children--;
 725                        free(blanket);
 726                } else
 727                        cradle = &blanket->next;
 728}
 729
 730static char **cld_argv;
 731static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 732{
 733        struct child_process cld = { NULL };
 734        char addrbuf[300] = "REMOTE_ADDR=", portbuf[300];
 735        char *env[] = { addrbuf, portbuf, NULL };
 736
 737        if (max_connections && live_children >= max_connections) {
 738                kill_some_child();
 739                sleep(1);  /* give it some time to die */
 740                check_dead_children();
 741                if (live_children >= max_connections) {
 742                        close(incoming);
 743                        logerror("Too many children, dropping connection");
 744                        return;
 745                }
 746        }
 747
 748        if (addr->sa_family == AF_INET) {
 749                struct sockaddr_in *sin_addr = (void *) addr;
 750                inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf + 12,
 751                    sizeof(addrbuf) - 12);
 752                snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 753                    ntohs(sin_addr->sin_port));
 754#ifndef NO_IPV6
 755        } else if (addr->sa_family == AF_INET6) {
 756                struct sockaddr_in6 *sin6_addr = (void *) addr;
 757
 758                char *buf = addrbuf + 12;
 759                *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 760                inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf,
 761                    sizeof(addrbuf) - 13);
 762                strcat(buf, "]");
 763
 764                snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 765                    ntohs(sin6_addr->sin6_port));
 766#endif
 767        }
 768
 769        cld.env = (const char **)env;
 770        cld.argv = (const char **)cld_argv;
 771        cld.in = incoming;
 772        cld.out = dup(incoming);
 773
 774        if (start_command(&cld))
 775                logerror("unable to fork");
 776        else
 777                add_child(&cld, addr, addrlen);
 778        close(incoming);
 779}
 780
 781static void child_handler(int signo)
 782{
 783        /*
 784         * Otherwise empty handler because systemcalls will get interrupted
 785         * upon signal receipt
 786         * SysV needs the handler to be rearmed
 787         */
 788        signal(SIGCHLD, child_handler);
 789}
 790
 791static int set_reuse_addr(int sockfd)
 792{
 793        int on = 1;
 794
 795        if (!reuseaddr)
 796                return 0;
 797        return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 798                          &on, sizeof(on));
 799}
 800
 801struct socketlist {
 802        int *list;
 803        size_t nr;
 804        size_t alloc;
 805};
 806
 807static const char *ip2str(int family, struct sockaddr *sin, socklen_t len)
 808{
 809#ifdef NO_IPV6
 810        static char ip[INET_ADDRSTRLEN];
 811#else
 812        static char ip[INET6_ADDRSTRLEN];
 813#endif
 814
 815        switch (family) {
 816#ifndef NO_IPV6
 817        case AF_INET6:
 818                inet_ntop(family, &((struct sockaddr_in6*)sin)->sin6_addr, ip, len);
 819                break;
 820#endif
 821        case AF_INET:
 822                inet_ntop(family, &((struct sockaddr_in*)sin)->sin_addr, ip, len);
 823                break;
 824        default:
 825                strcpy(ip, "<unknown>");
 826        }
 827        return ip;
 828}
 829
 830#ifndef NO_IPV6
 831
 832static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 833{
 834        int socknum = 0;
 835        int maxfd = -1;
 836        char pbuf[NI_MAXSERV];
 837        struct addrinfo hints, *ai0, *ai;
 838        int gai;
 839        long flags;
 840
 841        sprintf(pbuf, "%d", listen_port);
 842        memset(&hints, 0, sizeof(hints));
 843        hints.ai_family = AF_UNSPEC;
 844        hints.ai_socktype = SOCK_STREAM;
 845        hints.ai_protocol = IPPROTO_TCP;
 846        hints.ai_flags = AI_PASSIVE;
 847
 848        gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 849        if (gai) {
 850                logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
 851                return 0;
 852        }
 853
 854        for (ai = ai0; ai; ai = ai->ai_next) {
 855                int sockfd;
 856
 857                sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 858                if (sockfd < 0)
 859                        continue;
 860                if (sockfd >= FD_SETSIZE) {
 861                        logerror("Socket descriptor too large");
 862                        close(sockfd);
 863                        continue;
 864                }
 865
 866#ifdef IPV6_V6ONLY
 867                if (ai->ai_family == AF_INET6) {
 868                        int on = 1;
 869                        setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 870                                   &on, sizeof(on));
 871                        /* Note: error is not fatal */
 872                }
 873#endif
 874
 875                if (set_reuse_addr(sockfd)) {
 876                        logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 877                        close(sockfd);
 878                        continue;
 879                }
 880
 881                if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 882                        logerror("Could not bind to %s: %s",
 883                                 ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 884                                 strerror(errno));
 885                        close(sockfd);
 886                        continue;       /* not fatal */
 887                }
 888                if (listen(sockfd, 5) < 0) {
 889                        logerror("Could not listen to %s: %s",
 890                                 ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 891                                 strerror(errno));
 892                        close(sockfd);
 893                        continue;       /* not fatal */
 894                }
 895
 896                flags = fcntl(sockfd, F_GETFD, 0);
 897                if (flags >= 0)
 898                        fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 899
 900                ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 901                socklist->list[socklist->nr++] = sockfd;
 902                socknum++;
 903
 904                if (maxfd < sockfd)
 905                        maxfd = sockfd;
 906        }
 907
 908        freeaddrinfo(ai0);
 909
 910        return socknum;
 911}
 912
 913#else /* NO_IPV6 */
 914
 915static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 916{
 917        struct sockaddr_in sin;
 918        int sockfd;
 919        long flags;
 920
 921        memset(&sin, 0, sizeof sin);
 922        sin.sin_family = AF_INET;
 923        sin.sin_port = htons(listen_port);
 924
 925        if (listen_addr) {
 926                /* Well, host better be an IP address here. */
 927                if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 928                        return 0;
 929        } else {
 930                sin.sin_addr.s_addr = htonl(INADDR_ANY);
 931        }
 932
 933        sockfd = socket(AF_INET, SOCK_STREAM, 0);
 934        if (sockfd < 0)
 935                return 0;
 936
 937        if (set_reuse_addr(sockfd)) {
 938                logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 939                close(sockfd);
 940                return 0;
 941        }
 942
 943        if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 944                logerror("Could not listen to %s: %s",
 945                         ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
 946                         strerror(errno));
 947                close(sockfd);
 948                return 0;
 949        }
 950
 951        if (listen(sockfd, 5) < 0) {
 952                logerror("Could not listen to %s: %s",
 953                         ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
 954                         strerror(errno));
 955                close(sockfd);
 956                return 0;
 957        }
 958
 959        flags = fcntl(sockfd, F_GETFD, 0);
 960        if (flags >= 0)
 961                fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 962
 963        ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 964        socklist->list[socklist->nr++] = sockfd;
 965        return 1;
 966}
 967
 968#endif
 969
 970static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
 971{
 972        if (!listen_addr->nr)
 973                setup_named_sock(NULL, listen_port, socklist);
 974        else {
 975                int i, socknum;
 976                for (i = 0; i < listen_addr->nr; i++) {
 977                        socknum = setup_named_sock(listen_addr->items[i].string,
 978                                                   listen_port, socklist);
 979
 980                        if (socknum == 0)
 981                                logerror("unable to allocate any listen sockets for host %s on port %u",
 982                                         listen_addr->items[i].string, listen_port);
 983                }
 984        }
 985}
 986
 987static int service_loop(struct socketlist *socklist)
 988{
 989        struct pollfd *pfd;
 990        int i;
 991
 992        pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
 993
 994        for (i = 0; i < socklist->nr; i++) {
 995                pfd[i].fd = socklist->list[i];
 996                pfd[i].events = POLLIN;
 997        }
 998
 999        signal(SIGCHLD, child_handler);
1000
1001        for (;;) {
1002                int i;
1003
1004                check_dead_children();
1005
1006                if (poll(pfd, socklist->nr, -1) < 0) {
1007                        if (errno != EINTR) {
1008                                logerror("Poll failed, resuming: %s",
1009                                      strerror(errno));
1010                                sleep(1);
1011                        }
1012                        continue;
1013                }
1014
1015                for (i = 0; i < socklist->nr; i++) {
1016                        if (pfd[i].revents & POLLIN) {
1017                                union {
1018                                        struct sockaddr sa;
1019                                        struct sockaddr_in sai;
1020#ifndef NO_IPV6
1021                                        struct sockaddr_in6 sai6;
1022#endif
1023                                } ss;
1024                                socklen_t sslen = sizeof(ss);
1025                                int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
1026                                if (incoming < 0) {
1027                                        switch (errno) {
1028                                        case EAGAIN:
1029                                        case EINTR:
1030                                        case ECONNABORTED:
1031                                                continue;
1032                                        default:
1033                                                die_errno("accept returned");
1034                                        }
1035                                }
1036                                handle(incoming, &ss.sa, sslen);
1037                        }
1038                }
1039        }
1040}
1041
1042#ifdef NO_POSIX_GOODIES
1043
1044struct credentials;
1045
1046static void drop_privileges(struct credentials *cred)
1047{
1048        /* nothing */
1049}
1050
1051static struct credentials *prepare_credentials(const char *user_name,
1052    const char *group_name)
1053{
1054        die("--user not supported on this platform");
1055}
1056
1057#else
1058
1059struct credentials {
1060        struct passwd *pass;
1061        gid_t gid;
1062};
1063
1064static void drop_privileges(struct credentials *cred)
1065{
1066        if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
1067            setgid (cred->gid) || setuid(cred->pass->pw_uid)))
1068                die("cannot drop privileges");
1069}
1070
1071static struct credentials *prepare_credentials(const char *user_name,
1072    const char *group_name)
1073{
1074        static struct credentials c;
1075
1076        c.pass = getpwnam(user_name);
1077        if (!c.pass)
1078                die("user not found - %s", user_name);
1079
1080        if (!group_name)
1081                c.gid = c.pass->pw_gid;
1082        else {
1083                struct group *group = getgrnam(group_name);
1084                if (!group)
1085                        die("group not found - %s", group_name);
1086
1087                c.gid = group->gr_gid;
1088        }
1089
1090        return &c;
1091}
1092#endif
1093
1094static void store_pid(const char *path)
1095{
1096        FILE *f = fopen(path, "w");
1097        if (!f)
1098                die_errno("cannot open pid file '%s'", path);
1099        if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
1100                die_errno("failed to write pid file '%s'", path);
1101}
1102
1103static int serve(struct string_list *listen_addr, int listen_port,
1104    struct credentials *cred)
1105{
1106        struct socketlist socklist = { NULL, 0, 0 };
1107
1108        socksetup(listen_addr, listen_port, &socklist);
1109        if (socklist.nr == 0)
1110                die("unable to allocate any listen sockets on port %u",
1111                    listen_port);
1112
1113        drop_privileges(cred);
1114
1115        loginfo("Ready to rumble");
1116
1117        return service_loop(&socklist);
1118}
1119
1120int main(int argc, char **argv)
1121{
1122        int listen_port = 0;
1123        struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1124        int serve_mode = 0, inetd_mode = 0;
1125        const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1126        int detach = 0;
1127        struct credentials *cred = NULL;
1128        int i;
1129
1130        git_setup_gettext();
1131
1132        git_extract_argv0_path(argv[0]);
1133
1134        for (i = 1; i < argc; i++) {
1135                char *arg = argv[i];
1136
1137                if (starts_with(arg, "--listen=")) {
1138                        string_list_append(&listen_addr, xstrdup_tolower(arg + 9));
1139                        continue;
1140                }
1141                if (starts_with(arg, "--port=")) {
1142                        char *end;
1143                        unsigned long n;
1144                        n = strtoul(arg+7, &end, 0);
1145                        if (arg[7] && !*end) {
1146                                listen_port = n;
1147                                continue;
1148                        }
1149                }
1150                if (!strcmp(arg, "--serve")) {
1151                        serve_mode = 1;
1152                        continue;
1153                }
1154                if (!strcmp(arg, "--inetd")) {
1155                        inetd_mode = 1;
1156                        log_syslog = 1;
1157                        continue;
1158                }
1159                if (!strcmp(arg, "--verbose")) {
1160                        verbose = 1;
1161                        continue;
1162                }
1163                if (!strcmp(arg, "--syslog")) {
1164                        log_syslog = 1;
1165                        continue;
1166                }
1167                if (!strcmp(arg, "--export-all")) {
1168                        export_all_trees = 1;
1169                        continue;
1170                }
1171                if (starts_with(arg, "--access-hook=")) {
1172                        access_hook = arg + 14;
1173                        continue;
1174                }
1175                if (starts_with(arg, "--timeout=")) {
1176                        timeout = atoi(arg+10);
1177                        continue;
1178                }
1179                if (starts_with(arg, "--init-timeout=")) {
1180                        init_timeout = atoi(arg+15);
1181                        continue;
1182                }
1183                if (starts_with(arg, "--max-connections=")) {
1184                        max_connections = atoi(arg+18);
1185                        if (max_connections < 0)
1186                                max_connections = 0;            /* unlimited */
1187                        continue;
1188                }
1189                if (!strcmp(arg, "--strict-paths")) {
1190                        strict_paths = 1;
1191                        continue;
1192                }
1193                if (starts_with(arg, "--base-path=")) {
1194                        base_path = arg+12;
1195                        continue;
1196                }
1197                if (!strcmp(arg, "--base-path-relaxed")) {
1198                        base_path_relaxed = 1;
1199                        continue;
1200                }
1201                if (starts_with(arg, "--interpolated-path=")) {
1202                        interpolated_path = arg+20;
1203                        continue;
1204                }
1205                if (!strcmp(arg, "--reuseaddr")) {
1206                        reuseaddr = 1;
1207                        continue;
1208                }
1209                if (!strcmp(arg, "--user-path")) {
1210                        user_path = "";
1211                        continue;
1212                }
1213                if (starts_with(arg, "--user-path=")) {
1214                        user_path = arg + 12;
1215                        continue;
1216                }
1217                if (starts_with(arg, "--pid-file=")) {
1218                        pid_file = arg + 11;
1219                        continue;
1220                }
1221                if (!strcmp(arg, "--detach")) {
1222                        detach = 1;
1223                        log_syslog = 1;
1224                        continue;
1225                }
1226                if (starts_with(arg, "--user=")) {
1227                        user_name = arg + 7;
1228                        continue;
1229                }
1230                if (starts_with(arg, "--group=")) {
1231                        group_name = arg + 8;
1232                        continue;
1233                }
1234                if (starts_with(arg, "--enable=")) {
1235                        enable_service(arg + 9, 1);
1236                        continue;
1237                }
1238                if (starts_with(arg, "--disable=")) {
1239                        enable_service(arg + 10, 0);
1240                        continue;
1241                }
1242                if (starts_with(arg, "--allow-override=")) {
1243                        make_service_overridable(arg + 17, 1);
1244                        continue;
1245                }
1246                if (starts_with(arg, "--forbid-override=")) {
1247                        make_service_overridable(arg + 18, 0);
1248                        continue;
1249                }
1250                if (!strcmp(arg, "--informative-errors")) {
1251                        informative_errors = 1;
1252                        continue;
1253                }
1254                if (!strcmp(arg, "--no-informative-errors")) {
1255                        informative_errors = 0;
1256                        continue;
1257                }
1258                if (!strcmp(arg, "--")) {
1259                        ok_paths = &argv[i+1];
1260                        break;
1261                } else if (arg[0] != '-') {
1262                        ok_paths = &argv[i];
1263                        break;
1264                }
1265
1266                usage(daemon_usage);
1267        }
1268
1269        if (log_syslog) {
1270                openlog("git-daemon", LOG_PID, LOG_DAEMON);
1271                set_die_routine(daemon_die);
1272        } else
1273                /* avoid splitting a message in the middle */
1274                setvbuf(stderr, NULL, _IOFBF, 4096);
1275
1276        if (inetd_mode && (detach || group_name || user_name))
1277                die("--detach, --user and --group are incompatible with --inetd");
1278
1279        if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1280                die("--listen= and --port= are incompatible with --inetd");
1281        else if (listen_port == 0)
1282                listen_port = DEFAULT_GIT_PORT;
1283
1284        if (group_name && !user_name)
1285                die("--group supplied without --user");
1286
1287        if (user_name)
1288                cred = prepare_credentials(user_name, group_name);
1289
1290        if (strict_paths && (!ok_paths || !*ok_paths))
1291                die("option --strict-paths requires a whitelist");
1292
1293        if (base_path && !is_directory(base_path))
1294                die("base-path '%s' does not exist or is not a directory",
1295                    base_path);
1296
1297        if (inetd_mode) {
1298                if (!freopen("/dev/null", "w", stderr))
1299                        die_errno("failed to redirect stderr to /dev/null");
1300        }
1301
1302        if (inetd_mode || serve_mode)
1303                return execute();
1304
1305        if (detach) {
1306                if (daemonize())
1307                        die("--detach not supported on this platform");
1308        } else
1309                sanitize_stdfds();
1310
1311        if (pid_file)
1312                store_pid(pid_file);
1313
1314        /* prepare argv for serving-processes */
1315        cld_argv = xmalloc(sizeof (char *) * (argc + 2));
1316        cld_argv[0] = argv[0];  /* git-daemon */
1317        cld_argv[1] = "--serve";
1318        for (i = 1; i < argc; ++i)
1319                cld_argv[i+1] = argv[i];
1320        cld_argv[argc+1] = NULL;
1321
1322        return serve(&listen_addr, listen_port, cred);
1323}