Andrew's git / gitweb.git / daemon.c
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daemon.con commit cherry-pick: handle root commits with external strategies (1618073)
   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#ifndef NI_MAXSERV
  13#define NI_MAXSERV 32
  14#endif
  15
  16#ifdef NO_INITGROUPS
  17#define initgroups(x, y) (0) /* nothing */
  18#endif
  19
  20static int log_syslog;
  21static int verbose;
  22static int reuseaddr;
  23
  24static const char daemon_usage[] =
  25"git daemon [--verbose] [--syslog] [--export-all]\n"
  26"           [--timeout=<n>] [--init-timeout=<n>] [--max-connections=<n>]\n"
  27"           [--strict-paths] [--base-path=<path>] [--base-path-relaxed]\n"
  28"           [--user-path | --user-path=<path>]\n"
  29"           [--interpolated-path=<path>]\n"
  30"           [--reuseaddr] [--pid-file=<file>]\n"
  31"           [--(enable|disable|allow-override|forbid-override)=<service>]\n"
  32"           [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
  33"                      [--detach] [--user=<user> [--group=<group>]]\n"
  34"           [<directory>...]";
  35
  36/* List of acceptable pathname prefixes */
  37static char **ok_paths;
  38static int strict_paths;
  39
  40/* If this is set, git-daemon-export-ok is not required */
  41static int export_all_trees;
  42
  43/* Take all paths relative to this one if non-NULL */
  44static char *base_path;
  45static char *interpolated_path;
  46static int base_path_relaxed;
  47
  48/* Flag indicating client sent extra args. */
  49static int saw_extended_args;
  50
  51/* If defined, ~user notation is allowed and the string is inserted
  52 * after ~user/.  E.g. a request to git://host/~alice/frotz would
  53 * go to /home/alice/pub_git/frotz with --user-path=pub_git.
  54 */
  55static const char *user_path;
  56
  57/* Timeout, and initial timeout */
  58static unsigned int timeout;
  59static unsigned int init_timeout;
  60
  61static char *hostname;
  62static char *canon_hostname;
  63static char *ip_address;
  64static char *tcp_port;
  65
  66static void logreport(int priority, const char *err, va_list params)
  67{
  68        if (log_syslog) {
  69                char buf[1024];
  70                vsnprintf(buf, sizeof(buf), err, params);
  71                syslog(priority, "%s", buf);
  72        } else {
  73                /*
  74                 * Since stderr is set to buffered mode, the
  75                 * logging of different processes will not overlap
  76                 * unless they overflow the (rather big) buffers.
  77                 */
  78                fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
  79                vfprintf(stderr, err, params);
  80                fputc('\n', stderr);
  81                fflush(stderr);
  82        }
  83}
  84
  85__attribute__((format (printf, 1, 2)))
  86static void logerror(const char *err, ...)
  87{
  88        va_list params;
  89        va_start(params, err);
  90        logreport(LOG_ERR, err, params);
  91        va_end(params);
  92}
  93
  94__attribute__((format (printf, 1, 2)))
  95static void loginfo(const char *err, ...)
  96{
  97        va_list params;
  98        if (!verbose)
  99                return;
 100        va_start(params, err);
 101        logreport(LOG_INFO, err, params);
 102        va_end(params);
 103}
 104
 105static void NORETURN daemon_die(const char *err, va_list params)
 106{
 107        logreport(LOG_ERR, err, params);
 108        exit(1);
 109}
 110
 111static char *path_ok(char *directory)
 112{
 113        static char rpath[PATH_MAX];
 114        static char interp_path[PATH_MAX];
 115        char *path;
 116        char *dir;
 117
 118        dir = directory;
 119
 120        if (daemon_avoid_alias(dir)) {
 121                logerror("'%s': aliased", dir);
 122                return NULL;
 123        }
 124
 125        if (*dir == '~') {
 126                if (!user_path) {
 127                        logerror("'%s': User-path not allowed", dir);
 128                        return NULL;
 129                }
 130                if (*user_path) {
 131                        /* Got either "~alice" or "~alice/foo";
 132                         * rewrite them to "~alice/%s" or
 133                         * "~alice/%s/foo".
 134                         */
 135                        int namlen, restlen = strlen(dir);
 136                        char *slash = strchr(dir, '/');
 137                        if (!slash)
 138                                slash = dir + restlen;
 139                        namlen = slash - dir;
 140                        restlen -= namlen;
 141                        loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
 142                        snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
 143                                 namlen, dir, user_path, restlen, slash);
 144                        dir = rpath;
 145                }
 146        }
 147        else if (interpolated_path && saw_extended_args) {
 148                struct strbuf expanded_path = STRBUF_INIT;
 149                struct strbuf_expand_dict_entry dict[6];
 150
 151                dict[0].placeholder = "H"; dict[0].value = hostname;
 152                dict[1].placeholder = "CH"; dict[1].value = canon_hostname;
 153                dict[2].placeholder = "IP"; dict[2].value = ip_address;
 154                dict[3].placeholder = "P"; dict[3].value = tcp_port;
 155                dict[4].placeholder = "D"; dict[4].value = directory;
 156                dict[5].placeholder = NULL; dict[5].value = NULL;
 157                if (*dir != '/') {
 158                        /* Allow only absolute */
 159                        logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 160                        return NULL;
 161                }
 162
 163                strbuf_expand(&expanded_path, interpolated_path,
 164                                strbuf_expand_dict_cb, &dict);
 165                strlcpy(interp_path, expanded_path.buf, PATH_MAX);
 166                strbuf_release(&expanded_path);
 167                loginfo("Interpolated dir '%s'", interp_path);
 168
 169                dir = interp_path;
 170        }
 171        else if (base_path) {
 172                if (*dir != '/') {
 173                        /* Allow only absolute */
 174                        logerror("'%s': Non-absolute path denied (base-path active)", dir);
 175                        return NULL;
 176                }
 177                snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
 178                dir = rpath;
 179        }
 180
 181        path = enter_repo(dir, strict_paths);
 182        if (!path && base_path && base_path_relaxed) {
 183                /*
 184                 * if we fail and base_path_relaxed is enabled, try without
 185                 * prefixing the base path
 186                 */
 187                dir = directory;
 188                path = enter_repo(dir, strict_paths);
 189        }
 190
 191        if (!path) {
 192                logerror("'%s' does not appear to be a git repository", dir);
 193                return NULL;
 194        }
 195
 196        if ( ok_paths && *ok_paths ) {
 197                char **pp;
 198                int pathlen = strlen(path);
 199
 200                /* The validation is done on the paths after enter_repo
 201                 * appends optional {.git,.git/.git} and friends, but
 202                 * it does not use getcwd().  So if your /pub is
 203                 * a symlink to /mnt/pub, you can whitelist /pub and
 204                 * do not have to say /mnt/pub.
 205                 * Do not say /pub/.
 206                 */
 207                for ( pp = ok_paths ; *pp ; pp++ ) {
 208                        int len = strlen(*pp);
 209                        if (len <= pathlen &&
 210                            !memcmp(*pp, path, len) &&
 211                            (path[len] == '\0' ||
 212                             (!strict_paths && path[len] == '/')))
 213                                return path;
 214                }
 215        }
 216        else {
 217                /* be backwards compatible */
 218                if (!strict_paths)
 219                        return path;
 220        }
 221
 222        logerror("'%s': not in whitelist", path);
 223        return NULL;            /* Fallthrough. Deny by default */
 224}
 225
 226typedef int (*daemon_service_fn)(void);
 227struct daemon_service {
 228        const char *name;
 229        const char *config_name;
 230        daemon_service_fn fn;
 231        int enabled;
 232        int overridable;
 233};
 234
 235static struct daemon_service *service_looking_at;
 236static int service_enabled;
 237
 238static int git_daemon_config(const char *var, const char *value, void *cb)
 239{
 240        if (!prefixcmp(var, "daemon.") &&
 241            !strcmp(var + 7, service_looking_at->config_name)) {
 242                service_enabled = git_config_bool(var, value);
 243                return 0;
 244        }
 245
 246        /* we are not interested in parsing any other configuration here */
 247        return 0;
 248}
 249
 250static int run_service(char *dir, struct daemon_service *service)
 251{
 252        const char *path;
 253        int enabled = service->enabled;
 254
 255        loginfo("Request %s for '%s'", service->name, dir);
 256
 257        if (!enabled && !service->overridable) {
 258                logerror("'%s': service not enabled.", service->name);
 259                errno = EACCES;
 260                return -1;
 261        }
 262
 263        if (!(path = path_ok(dir)))
 264                return -1;
 265
 266        /*
 267         * Security on the cheap.
 268         *
 269         * We want a readable HEAD, usable "objects" directory, and
 270         * a "git-daemon-export-ok" flag that says that the other side
 271         * is ok with us doing this.
 272         *
 273         * path_ok() uses enter_repo() and does whitelist checking.
 274         * We only need to make sure the repository is exported.
 275         */
 276
 277        if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 278                logerror("'%s': repository not exported.", path);
 279                errno = EACCES;
 280                return -1;
 281        }
 282
 283        if (service->overridable) {
 284                service_looking_at = service;
 285                service_enabled = -1;
 286                git_config(git_daemon_config, NULL);
 287                if (0 <= service_enabled)
 288                        enabled = service_enabled;
 289        }
 290        if (!enabled) {
 291                logerror("'%s': service not enabled for '%s'",
 292                         service->name, path);
 293                errno = EACCES;
 294                return -1;
 295        }
 296
 297        /*
 298         * We'll ignore SIGTERM from now on, we have a
 299         * good client.
 300         */
 301        signal(SIGTERM, SIG_IGN);
 302
 303        return service->fn();
 304}
 305
 306static void copy_to_log(int fd)
 307{
 308        struct strbuf line = STRBUF_INIT;
 309        FILE *fp;
 310
 311        fp = fdopen(fd, "r");
 312        if (fp == NULL) {
 313                logerror("fdopen of error channel failed");
 314                close(fd);
 315                return;
 316        }
 317
 318        while (strbuf_getline(&line, fp, '\n') != EOF) {
 319                logerror("%s", line.buf);
 320                strbuf_setlen(&line, 0);
 321        }
 322
 323        strbuf_release(&line);
 324        fclose(fp);
 325}
 326
 327static int run_service_command(const char **argv)
 328{
 329        struct child_process cld;
 330
 331        memset(&cld, 0, sizeof(cld));
 332        cld.argv = argv;
 333        cld.git_cmd = 1;
 334        cld.err = -1;
 335        if (start_command(&cld))
 336                return -1;
 337
 338        close(0);
 339        close(1);
 340
 341        copy_to_log(cld.err);
 342
 343        return finish_command(&cld);
 344}
 345
 346static int upload_pack(void)
 347{
 348        /* Timeout as string */
 349        char timeout_buf[64];
 350        const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
 351
 352        argv[2] = timeout_buf;
 353
 354        snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 355        return run_service_command(argv);
 356}
 357
 358static int upload_archive(void)
 359{
 360        static const char *argv[] = { "upload-archive", ".", NULL };
 361        return run_service_command(argv);
 362}
 363
 364static int receive_pack(void)
 365{
 366        static const char *argv[] = { "receive-pack", ".", NULL };
 367        return run_service_command(argv);
 368}
 369
 370static struct daemon_service daemon_service[] = {
 371        { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 372        { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 373        { "receive-pack", "receivepack", receive_pack, 0, 1 },
 374};
 375
 376static void enable_service(const char *name, int ena)
 377{
 378        int i;
 379        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 380                if (!strcmp(daemon_service[i].name, name)) {
 381                        daemon_service[i].enabled = ena;
 382                        return;
 383                }
 384        }
 385        die("No such service %s", name);
 386}
 387
 388static void make_service_overridable(const char *name, int ena)
 389{
 390        int i;
 391        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 392                if (!strcmp(daemon_service[i].name, name)) {
 393                        daemon_service[i].overridable = ena;
 394                        return;
 395                }
 396        }
 397        die("No such service %s", name);
 398}
 399
 400static char *xstrdup_tolower(const char *str)
 401{
 402        char *p, *dup = xstrdup(str);
 403        for (p = dup; *p; p++)
 404                *p = tolower(*p);
 405        return dup;
 406}
 407
 408static void parse_host_and_port(char *hostport, char **host,
 409        char **port)
 410{
 411        if (*hostport == '[') {
 412                char *end;
 413
 414                end = strchr(hostport, ']');
 415                if (!end)
 416                        die("Invalid request ('[' without ']')");
 417                *end = '\0';
 418                *host = hostport + 1;
 419                if (!end[1])
 420                        *port = NULL;
 421                else if (end[1] == ':')
 422                        *port = end + 2;
 423                else
 424                        die("Garbage after end of host part");
 425        } else {
 426                *host = hostport;
 427                *port = strrchr(hostport, ':');
 428                if (*port) {
 429                        **port = '\0';
 430                        ++*port;
 431                }
 432        }
 433}
 434
 435/*
 436 * Read the host as supplied by the client connection.
 437 */
 438static void parse_host_arg(char *extra_args, int buflen)
 439{
 440        char *val;
 441        int vallen;
 442        char *end = extra_args + buflen;
 443
 444        if (extra_args < end && *extra_args) {
 445                saw_extended_args = 1;
 446                if (strncasecmp("host=", extra_args, 5) == 0) {
 447                        val = extra_args + 5;
 448                        vallen = strlen(val) + 1;
 449                        if (*val) {
 450                                /* Split <host>:<port> at colon. */
 451                                char *host;
 452                                char *port;
 453                                parse_host_and_port(val, &host, &port);
 454                                if (port) {
 455                                        free(tcp_port);
 456                                        tcp_port = xstrdup(port);
 457                                }
 458                                free(hostname);
 459                                hostname = xstrdup_tolower(host);
 460                        }
 461
 462                        /* On to the next one */
 463                        extra_args = val + vallen;
 464                }
 465                if (extra_args < end && *extra_args)
 466                        die("Invalid request");
 467        }
 468
 469        /*
 470         * Locate canonical hostname and its IP address.
 471         */
 472        if (hostname) {
 473#ifndef NO_IPV6
 474                struct addrinfo hints;
 475                struct addrinfo *ai;
 476                int gai;
 477                static char addrbuf[HOST_NAME_MAX + 1];
 478
 479                memset(&hints, 0, sizeof(hints));
 480                hints.ai_flags = AI_CANONNAME;
 481
 482                gai = getaddrinfo(hostname, NULL, &hints, &ai);
 483                if (!gai) {
 484                        struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 485
 486                        inet_ntop(AF_INET, &sin_addr->sin_addr,
 487                                  addrbuf, sizeof(addrbuf));
 488                        free(ip_address);
 489                        ip_address = xstrdup(addrbuf);
 490
 491                        free(canon_hostname);
 492                        canon_hostname = xstrdup(ai->ai_canonname ?
 493                                                 ai->ai_canonname : ip_address);
 494
 495                        freeaddrinfo(ai);
 496                }
 497#else
 498                struct hostent *hent;
 499                struct sockaddr_in sa;
 500                char **ap;
 501                static char addrbuf[HOST_NAME_MAX + 1];
 502
 503                hent = gethostbyname(hostname);
 504
 505                ap = hent->h_addr_list;
 506                memset(&sa, 0, sizeof sa);
 507                sa.sin_family = hent->h_addrtype;
 508                sa.sin_port = htons(0);
 509                memcpy(&sa.sin_addr, *ap, hent->h_length);
 510
 511                inet_ntop(hent->h_addrtype, &sa.sin_addr,
 512                          addrbuf, sizeof(addrbuf));
 513
 514                free(canon_hostname);
 515                canon_hostname = xstrdup(hent->h_name);
 516                free(ip_address);
 517                ip_address = xstrdup(addrbuf);
 518#endif
 519        }
 520}
 521
 522
 523static int execute(void)
 524{
 525        static char line[1000];
 526        int pktlen, len, i;
 527        char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
 528
 529        if (addr)
 530                loginfo("Connection from %s:%s", addr, port);
 531
 532        alarm(init_timeout ? init_timeout : timeout);
 533        pktlen = packet_read_line(0, line, sizeof(line));
 534        alarm(0);
 535
 536        len = strlen(line);
 537        if (pktlen != len)
 538                loginfo("Extended attributes (%d bytes) exist <%.*s>",
 539                        (int) pktlen - len,
 540                        (int) pktlen - len, line + len + 1);
 541        if (len && line[len-1] == '\n') {
 542                line[--len] = 0;
 543                pktlen--;
 544        }
 545
 546        free(hostname);
 547        free(canon_hostname);
 548        free(ip_address);
 549        free(tcp_port);
 550        hostname = canon_hostname = ip_address = tcp_port = NULL;
 551
 552        if (len != pktlen)
 553                parse_host_arg(line + len + 1, pktlen - len - 1);
 554
 555        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 556                struct daemon_service *s = &(daemon_service[i]);
 557                int namelen = strlen(s->name);
 558                if (!prefixcmp(line, "git-") &&
 559                    !strncmp(s->name, line + 4, namelen) &&
 560                    line[namelen + 4] == ' ') {
 561                        /*
 562                         * Note: The directory here is probably context sensitive,
 563                         * and might depend on the actual service being performed.
 564                         */
 565                        return run_service(line + namelen + 5, s);
 566                }
 567        }
 568
 569        logerror("Protocol error: '%s'", line);
 570        return -1;
 571}
 572
 573static int addrcmp(const struct sockaddr_storage *s1,
 574    const struct sockaddr_storage *s2)
 575{
 576        const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 577        const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 578
 579        if (sa1->sa_family != sa2->sa_family)
 580                return sa1->sa_family - sa2->sa_family;
 581        if (sa1->sa_family == AF_INET)
 582                return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 583                    &((struct sockaddr_in *)s2)->sin_addr,
 584                    sizeof(struct in_addr));
 585#ifndef NO_IPV6
 586        if (sa1->sa_family == AF_INET6)
 587                return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 588                    &((struct sockaddr_in6 *)s2)->sin6_addr,
 589                    sizeof(struct in6_addr));
 590#endif
 591        return 0;
 592}
 593
 594static int max_connections = 32;
 595
 596static unsigned int live_children;
 597
 598static struct child {
 599        struct child *next;
 600        struct child_process cld;
 601        struct sockaddr_storage address;
 602} *firstborn;
 603
 604static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
 605{
 606        struct child *newborn, **cradle;
 607
 608        newborn = xcalloc(1, sizeof(*newborn));
 609        live_children++;
 610        memcpy(&newborn->cld, cld, sizeof(*cld));
 611        memcpy(&newborn->address, addr, addrlen);
 612        for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 613                if (!addrcmp(&(*cradle)->address, &newborn->address))
 614                        break;
 615        newborn->next = *cradle;
 616        *cradle = newborn;
 617}
 618
 619/*
 620 * This gets called if the number of connections grows
 621 * past "max_connections".
 622 *
 623 * We kill the newest connection from a duplicate IP.
 624 */
 625static void kill_some_child(void)
 626{
 627        const struct child *blanket, *next;
 628
 629        if (!(blanket = firstborn))
 630                return;
 631
 632        for (; (next = blanket->next); blanket = next)
 633                if (!addrcmp(&blanket->address, &next->address)) {
 634                        kill(blanket->cld.pid, SIGTERM);
 635                        break;
 636                }
 637}
 638
 639static void check_dead_children(void)
 640{
 641        int status;
 642        pid_t pid;
 643
 644        struct child **cradle, *blanket;
 645        for (cradle = &firstborn; (blanket = *cradle);)
 646                if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
 647                        const char *dead = "";
 648                        if (status)
 649                                dead = " (with error)";
 650                        loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 651
 652                        /* remove the child */
 653                        *cradle = blanket->next;
 654                        live_children--;
 655                        free(blanket);
 656                } else
 657                        cradle = &blanket->next;
 658}
 659
 660static char **cld_argv;
 661static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 662{
 663        struct child_process cld = { NULL };
 664        char addrbuf[300] = "REMOTE_ADDR=", portbuf[300];
 665        char *env[] = { addrbuf, portbuf, NULL };
 666
 667        if (max_connections && live_children >= max_connections) {
 668                kill_some_child();
 669                sleep(1);  /* give it some time to die */
 670                check_dead_children();
 671                if (live_children >= max_connections) {
 672                        close(incoming);
 673                        logerror("Too many children, dropping connection");
 674                        return;
 675                }
 676        }
 677
 678        if (addr->sa_family == AF_INET) {
 679                struct sockaddr_in *sin_addr = (void *) addr;
 680                inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf + 12,
 681                    sizeof(addrbuf) - 12);
 682                snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 683                    ntohs(sin_addr->sin_port));
 684#ifndef NO_IPV6
 685        } else if (addr && addr->sa_family == AF_INET6) {
 686                struct sockaddr_in6 *sin6_addr = (void *) addr;
 687
 688                char *buf = addrbuf + 12;
 689                *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 690                inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf,
 691                    sizeof(addrbuf) - 13);
 692                strcat(buf, "]");
 693
 694                snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 695                    ntohs(sin6_addr->sin6_port));
 696#endif
 697        }
 698
 699        cld.env = (const char **)env;
 700        cld.argv = (const char **)cld_argv;
 701        cld.in = incoming;
 702        cld.out = dup(incoming);
 703
 704        if (start_command(&cld))
 705                logerror("unable to fork");
 706        else
 707                add_child(&cld, addr, addrlen);
 708        close(incoming);
 709}
 710
 711static void child_handler(int signo)
 712{
 713        /*
 714         * Otherwise empty handler because systemcalls will get interrupted
 715         * upon signal receipt
 716         * SysV needs the handler to be rearmed
 717         */
 718        signal(SIGCHLD, child_handler);
 719}
 720
 721static int set_reuse_addr(int sockfd)
 722{
 723        int on = 1;
 724
 725        if (!reuseaddr)
 726                return 0;
 727        return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 728                          &on, sizeof(on));
 729}
 730
 731struct socketlist {
 732        int *list;
 733        size_t nr;
 734        size_t alloc;
 735};
 736
 737#ifndef NO_IPV6
 738
 739static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 740{
 741        int socknum = 0;
 742        int maxfd = -1;
 743        char pbuf[NI_MAXSERV];
 744        struct addrinfo hints, *ai0, *ai;
 745        int gai;
 746        long flags;
 747
 748        sprintf(pbuf, "%d", listen_port);
 749        memset(&hints, 0, sizeof(hints));
 750        hints.ai_family = AF_UNSPEC;
 751        hints.ai_socktype = SOCK_STREAM;
 752        hints.ai_protocol = IPPROTO_TCP;
 753        hints.ai_flags = AI_PASSIVE;
 754
 755        gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 756        if (gai) {
 757                logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
 758                return 0;
 759        }
 760
 761        for (ai = ai0; ai; ai = ai->ai_next) {
 762                int sockfd;
 763
 764                sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 765                if (sockfd < 0)
 766                        continue;
 767                if (sockfd >= FD_SETSIZE) {
 768                        logerror("Socket descriptor too large");
 769                        close(sockfd);
 770                        continue;
 771                }
 772
 773#ifdef IPV6_V6ONLY
 774                if (ai->ai_family == AF_INET6) {
 775                        int on = 1;
 776                        setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 777                                   &on, sizeof(on));
 778                        /* Note: error is not fatal */
 779                }
 780#endif
 781
 782                if (set_reuse_addr(sockfd)) {
 783                        close(sockfd);
 784                        continue;
 785                }
 786
 787                if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 788                        close(sockfd);
 789                        continue;       /* not fatal */
 790                }
 791                if (listen(sockfd, 5) < 0) {
 792                        close(sockfd);
 793                        continue;       /* not fatal */
 794                }
 795
 796                flags = fcntl(sockfd, F_GETFD, 0);
 797                if (flags >= 0)
 798                        fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 799
 800                ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 801                socklist->list[socklist->nr++] = sockfd;
 802                socknum++;
 803
 804                if (maxfd < sockfd)
 805                        maxfd = sockfd;
 806        }
 807
 808        freeaddrinfo(ai0);
 809
 810        return socknum;
 811}
 812
 813#else /* NO_IPV6 */
 814
 815static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 816{
 817        struct sockaddr_in sin;
 818        int sockfd;
 819        long flags;
 820
 821        memset(&sin, 0, sizeof sin);
 822        sin.sin_family = AF_INET;
 823        sin.sin_port = htons(listen_port);
 824
 825        if (listen_addr) {
 826                /* Well, host better be an IP address here. */
 827                if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 828                        return 0;
 829        } else {
 830                sin.sin_addr.s_addr = htonl(INADDR_ANY);
 831        }
 832
 833        sockfd = socket(AF_INET, SOCK_STREAM, 0);
 834        if (sockfd < 0)
 835                return 0;
 836
 837        if (set_reuse_addr(sockfd)) {
 838                close(sockfd);
 839                return 0;
 840        }
 841
 842        if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 843                close(sockfd);
 844                return 0;
 845        }
 846
 847        if (listen(sockfd, 5) < 0) {
 848                close(sockfd);
 849                return 0;
 850        }
 851
 852        flags = fcntl(sockfd, F_GETFD, 0);
 853        if (flags >= 0)
 854                fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 855
 856        ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 857        socklist->list[socklist->nr++] = sockfd;
 858        return 1;
 859}
 860
 861#endif
 862
 863static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
 864{
 865        if (!listen_addr->nr)
 866                setup_named_sock(NULL, listen_port, socklist);
 867        else {
 868                int i, socknum;
 869                for (i = 0; i < listen_addr->nr; i++) {
 870                        socknum = setup_named_sock(listen_addr->items[i].string,
 871                                                   listen_port, socklist);
 872
 873                        if (socknum == 0)
 874                                logerror("unable to allocate any listen sockets for host %s on port %u",
 875                                         listen_addr->items[i].string, listen_port);
 876                }
 877        }
 878}
 879
 880static int service_loop(struct socketlist *socklist)
 881{
 882        struct pollfd *pfd;
 883        int i;
 884
 885        pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
 886
 887        for (i = 0; i < socklist->nr; i++) {
 888                pfd[i].fd = socklist->list[i];
 889                pfd[i].events = POLLIN;
 890        }
 891
 892        signal(SIGCHLD, child_handler);
 893
 894        for (;;) {
 895                int i;
 896
 897                check_dead_children();
 898
 899                if (poll(pfd, socklist->nr, -1) < 0) {
 900                        if (errno != EINTR) {
 901                                logerror("Poll failed, resuming: %s",
 902                                      strerror(errno));
 903                                sleep(1);
 904                        }
 905                        continue;
 906                }
 907
 908                for (i = 0; i < socklist->nr; i++) {
 909                        if (pfd[i].revents & POLLIN) {
 910                                union {
 911                                        struct sockaddr sa;
 912                                        struct sockaddr_in sai;
 913#ifndef NO_IPV6
 914                                        struct sockaddr_in6 sai6;
 915#endif
 916                                } ss;
 917                                socklen_t sslen = sizeof(ss);
 918                                int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
 919                                if (incoming < 0) {
 920                                        switch (errno) {
 921                                        case EAGAIN:
 922                                        case EINTR:
 923                                        case ECONNABORTED:
 924                                                continue;
 925                                        default:
 926                                                die_errno("accept returned");
 927                                        }
 928                                }
 929                                handle(incoming, &ss.sa, sslen);
 930                        }
 931                }
 932        }
 933}
 934
 935/* if any standard file descriptor is missing open it to /dev/null */
 936static void sanitize_stdfds(void)
 937{
 938        int fd = open("/dev/null", O_RDWR, 0);
 939        while (fd != -1 && fd < 2)
 940                fd = dup(fd);
 941        if (fd == -1)
 942                die_errno("open /dev/null or dup failed");
 943        if (fd > 2)
 944                close(fd);
 945}
 946
 947#ifdef NO_POSIX_GOODIES
 948
 949struct credentials;
 950
 951static void drop_privileges(struct credentials *cred)
 952{
 953        /* nothing */
 954}
 955
 956static void daemonize(void)
 957{
 958        die("--detach not supported on this platform");
 959}
 960
 961static struct credentials *prepare_credentials(const char *user_name,
 962    const char *group_name)
 963{
 964        die("--user not supported on this platform");
 965}
 966
 967#else
 968
 969struct credentials {
 970        struct passwd *pass;
 971        gid_t gid;
 972};
 973
 974static void drop_privileges(struct credentials *cred)
 975{
 976        if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
 977            setgid (cred->gid) || setuid(cred->pass->pw_uid)))
 978                die("cannot drop privileges");
 979}
 980
 981static struct credentials *prepare_credentials(const char *user_name,
 982    const char *group_name)
 983{
 984        static struct credentials c;
 985
 986        c.pass = getpwnam(user_name);
 987        if (!c.pass)
 988                die("user not found - %s", user_name);
 989
 990        if (!group_name)
 991                c.gid = c.pass->pw_gid;
 992        else {
 993                struct group *group = getgrnam(group_name);
 994                if (!group)
 995                        die("group not found - %s", group_name);
 996
 997                c.gid = group->gr_gid;
 998        }
 999
1000        return &c;
1001}
1002
1003static void daemonize(void)
1004{
1005        switch (fork()) {
1006                case 0:
1007                        break;
1008                case -1:
1009                        die_errno("fork failed");
1010                default:
1011                        exit(0);
1012        }
1013        if (setsid() == -1)
1014                die_errno("setsid failed");
1015        close(0);
1016        close(1);
1017        close(2);
1018        sanitize_stdfds();
1019}
1020#endif
1021
1022static void store_pid(const char *path)
1023{
1024        FILE *f = fopen(path, "w");
1025        if (!f)
1026                die_errno("cannot open pid file '%s'", path);
1027        if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
1028                die_errno("failed to write pid file '%s'", path);
1029}
1030
1031static int serve(struct string_list *listen_addr, int listen_port,
1032    struct credentials *cred)
1033{
1034        struct socketlist socklist = { NULL, 0, 0 };
1035
1036        socksetup(listen_addr, listen_port, &socklist);
1037        if (socklist.nr == 0)
1038                die("unable to allocate any listen sockets on port %u",
1039                    listen_port);
1040
1041        drop_privileges(cred);
1042
1043        return service_loop(&socklist);
1044}
1045
1046int main(int argc, char **argv)
1047{
1048        int listen_port = 0;
1049        struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1050        int serve_mode = 0, inetd_mode = 0;
1051        const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1052        int detach = 0;
1053        struct credentials *cred = NULL;
1054        int i;
1055
1056        git_extract_argv0_path(argv[0]);
1057
1058        for (i = 1; i < argc; i++) {
1059                char *arg = argv[i];
1060
1061                if (!prefixcmp(arg, "--listen=")) {
1062                        string_list_append(&listen_addr, xstrdup_tolower(arg + 9));
1063                        continue;
1064                }
1065                if (!prefixcmp(arg, "--port=")) {
1066                        char *end;
1067                        unsigned long n;
1068                        n = strtoul(arg+7, &end, 0);
1069                        if (arg[7] && !*end) {
1070                                listen_port = n;
1071                                continue;
1072                        }
1073                }
1074                if (!strcmp(arg, "--serve")) {
1075                        serve_mode = 1;
1076                        continue;
1077                }
1078                if (!strcmp(arg, "--inetd")) {
1079                        inetd_mode = 1;
1080                        log_syslog = 1;
1081                        continue;
1082                }
1083                if (!strcmp(arg, "--verbose")) {
1084                        verbose = 1;
1085                        continue;
1086                }
1087                if (!strcmp(arg, "--syslog")) {
1088                        log_syslog = 1;
1089                        continue;
1090                }
1091                if (!strcmp(arg, "--export-all")) {
1092                        export_all_trees = 1;
1093                        continue;
1094                }
1095                if (!prefixcmp(arg, "--timeout=")) {
1096                        timeout = atoi(arg+10);
1097                        continue;
1098                }
1099                if (!prefixcmp(arg, "--init-timeout=")) {
1100                        init_timeout = atoi(arg+15);
1101                        continue;
1102                }
1103                if (!prefixcmp(arg, "--max-connections=")) {
1104                        max_connections = atoi(arg+18);
1105                        if (max_connections < 0)
1106                                max_connections = 0;            /* unlimited */
1107                        continue;
1108                }
1109                if (!strcmp(arg, "--strict-paths")) {
1110                        strict_paths = 1;
1111                        continue;
1112                }
1113                if (!prefixcmp(arg, "--base-path=")) {
1114                        base_path = arg+12;
1115                        continue;
1116                }
1117                if (!strcmp(arg, "--base-path-relaxed")) {
1118                        base_path_relaxed = 1;
1119                        continue;
1120                }
1121                if (!prefixcmp(arg, "--interpolated-path=")) {
1122                        interpolated_path = arg+20;
1123                        continue;
1124                }
1125                if (!strcmp(arg, "--reuseaddr")) {
1126                        reuseaddr = 1;
1127                        continue;
1128                }
1129                if (!strcmp(arg, "--user-path")) {
1130                        user_path = "";
1131                        continue;
1132                }
1133                if (!prefixcmp(arg, "--user-path=")) {
1134                        user_path = arg + 12;
1135                        continue;
1136                }
1137                if (!prefixcmp(arg, "--pid-file=")) {
1138                        pid_file = arg + 11;
1139                        continue;
1140                }
1141                if (!strcmp(arg, "--detach")) {
1142                        detach = 1;
1143                        log_syslog = 1;
1144                        continue;
1145                }
1146                if (!prefixcmp(arg, "--user=")) {
1147                        user_name = arg + 7;
1148                        continue;
1149                }
1150                if (!prefixcmp(arg, "--group=")) {
1151                        group_name = arg + 8;
1152                        continue;
1153                }
1154                if (!prefixcmp(arg, "--enable=")) {
1155                        enable_service(arg + 9, 1);
1156                        continue;
1157                }
1158                if (!prefixcmp(arg, "--disable=")) {
1159                        enable_service(arg + 10, 0);
1160                        continue;
1161                }
1162                if (!prefixcmp(arg, "--allow-override=")) {
1163                        make_service_overridable(arg + 17, 1);
1164                        continue;
1165                }
1166                if (!prefixcmp(arg, "--forbid-override=")) {
1167                        make_service_overridable(arg + 18, 0);
1168                        continue;
1169                }
1170                if (!strcmp(arg, "--")) {
1171                        ok_paths = &argv[i+1];
1172                        break;
1173                } else if (arg[0] != '-') {
1174                        ok_paths = &argv[i];
1175                        break;
1176                }
1177
1178                usage(daemon_usage);
1179        }
1180
1181        if (log_syslog) {
1182                openlog("git-daemon", LOG_PID, LOG_DAEMON);
1183                set_die_routine(daemon_die);
1184        } else
1185                /* avoid splitting a message in the middle */
1186                setvbuf(stderr, NULL, _IOFBF, 4096);
1187
1188        if (inetd_mode && (detach || group_name || user_name))
1189                die("--detach, --user and --group are incompatible with --inetd");
1190
1191        if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1192                die("--listen= and --port= are incompatible with --inetd");
1193        else if (listen_port == 0)
1194                listen_port = DEFAULT_GIT_PORT;
1195
1196        if (group_name && !user_name)
1197                die("--group supplied without --user");
1198
1199        if (user_name)
1200                cred = prepare_credentials(user_name, group_name);
1201
1202        if (strict_paths && (!ok_paths || !*ok_paths))
1203                die("option --strict-paths requires a whitelist");
1204
1205        if (base_path && !is_directory(base_path))
1206                die("base-path '%s' does not exist or is not a directory",
1207                    base_path);
1208
1209        if (inetd_mode) {
1210                if (!freopen("/dev/null", "w", stderr))
1211                        die_errno("failed to redirect stderr to /dev/null");
1212        }
1213
1214        if (inetd_mode || serve_mode)
1215                return execute();
1216
1217        if (detach) {
1218                daemonize();
1219                loginfo("Ready to rumble");
1220        }
1221        else
1222                sanitize_stdfds();
1223
1224        if (pid_file)
1225                store_pid(pid_file);
1226
1227        /* prepare argv for serving-processes */
1228        cld_argv = xmalloc(sizeof (char *) * (argc + 2));
1229        cld_argv[0] = argv[0];  /* git-daemon */
1230        cld_argv[1] = "--serve";
1231        for (i = 1; i < argc; ++i)
1232                cld_argv[i+1] = argv[i];
1233        cld_argv[argc+1] = NULL;
1234
1235        return serve(&listen_addr, listen_port, cred);
1236}