Andrew's git / gitweb.git / daemon.c
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daemon.con commit add support for the SUA layer (interix; windows) (2844923)
   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#include <syslog.h>
   9
  10#ifndef HOST_NAME_MAX
  11#define HOST_NAME_MAX 256
  12#endif
  13
  14#ifndef NI_MAXSERV
  15#define NI_MAXSERV 32
  16#endif
  17
  18#ifdef NO_INITGROUPS
  19#define initgroups(x, y) (0) /* nothing */
  20#endif
  21
  22static int log_syslog;
  23static int verbose;
  24static int reuseaddr;
  25
  26static const char daemon_usage[] =
  27"git daemon [--verbose] [--syslog] [--export-all]\n"
  28"           [--timeout=<n>] [--init-timeout=<n>] [--max-connections=<n>]\n"
  29"           [--strict-paths] [--base-path=<path>] [--base-path-relaxed]\n"
  30"           [--user-path | --user-path=<path>]\n"
  31"           [--interpolated-path=<path>]\n"
  32"           [--reuseaddr] [--detach] [--pid-file=<file>]\n"
  33"           [--(enable|disable|allow-override|forbid-override)=<service>]\n"
  34"           [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
  35"                      [--user=<user> [--group=<group>]]\n"
  36"           [<directory>...]";
  37
  38/* List of acceptable pathname prefixes */
  39static char **ok_paths;
  40static int strict_paths;
  41
  42/* If this is set, git-daemon-export-ok is not required */
  43static int export_all_trees;
  44
  45/* Take all paths relative to this one if non-NULL */
  46static char *base_path;
  47static char *interpolated_path;
  48static int base_path_relaxed;
  49
  50/* Flag indicating client sent extra args. */
  51static int saw_extended_args;
  52
  53/* If defined, ~user notation is allowed and the string is inserted
  54 * after ~user/.  E.g. a request to git://host/~alice/frotz would
  55 * go to /home/alice/pub_git/frotz with --user-path=pub_git.
  56 */
  57static const char *user_path;
  58
  59/* Timeout, and initial timeout */
  60static unsigned int timeout;
  61static unsigned int init_timeout;
  62
  63static char *hostname;
  64static char *canon_hostname;
  65static char *ip_address;
  66static char *tcp_port;
  67
  68static void logreport(int priority, const char *err, va_list params)
  69{
  70        if (log_syslog) {
  71                char buf[1024];
  72                vsnprintf(buf, sizeof(buf), err, params);
  73                syslog(priority, "%s", buf);
  74        } else {
  75                /*
  76                 * Since stderr is set to linebuffered mode, the
  77                 * logging of different processes will not overlap
  78                 */
  79                fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
  80                vfprintf(stderr, err, params);
  81                fputc('\n', 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(struct sockaddr *addr)
 524{
 525        static char line[1000];
 526        int pktlen, len, i;
 527
 528        if (addr) {
 529                char addrbuf[256] = "";
 530                int port = -1;
 531
 532                if (addr->sa_family == AF_INET) {
 533                        struct sockaddr_in *sin_addr = (void *) addr;
 534                        inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
 535                        port = ntohs(sin_addr->sin_port);
 536#ifndef NO_IPV6
 537                } else if (addr && addr->sa_family == AF_INET6) {
 538                        struct sockaddr_in6 *sin6_addr = (void *) addr;
 539
 540                        char *buf = addrbuf;
 541                        *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 542                        inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
 543                        strcat(buf, "]");
 544
 545                        port = ntohs(sin6_addr->sin6_port);
 546#endif
 547                }
 548                loginfo("Connection from %s:%d", addrbuf, port);
 549                setenv("REMOTE_ADDR", addrbuf, 1);
 550        }
 551        else {
 552                unsetenv("REMOTE_ADDR");
 553        }
 554
 555        alarm(init_timeout ? init_timeout : timeout);
 556        pktlen = packet_read_line(0, line, sizeof(line));
 557        alarm(0);
 558
 559        len = strlen(line);
 560        if (pktlen != len)
 561                loginfo("Extended attributes (%d bytes) exist <%.*s>",
 562                        (int) pktlen - len,
 563                        (int) pktlen - len, line + len + 1);
 564        if (len && line[len-1] == '\n') {
 565                line[--len] = 0;
 566                pktlen--;
 567        }
 568
 569        free(hostname);
 570        free(canon_hostname);
 571        free(ip_address);
 572        free(tcp_port);
 573        hostname = canon_hostname = ip_address = tcp_port = NULL;
 574
 575        if (len != pktlen)
 576                parse_host_arg(line + len + 1, pktlen - len - 1);
 577
 578        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 579                struct daemon_service *s = &(daemon_service[i]);
 580                int namelen = strlen(s->name);
 581                if (!prefixcmp(line, "git-") &&
 582                    !strncmp(s->name, line + 4, namelen) &&
 583                    line[namelen + 4] == ' ') {
 584                        /*
 585                         * Note: The directory here is probably context sensitive,
 586                         * and might depend on the actual service being performed.
 587                         */
 588                        return run_service(line + namelen + 5, s);
 589                }
 590        }
 591
 592        logerror("Protocol error: '%s'", line);
 593        return -1;
 594}
 595
 596static int addrcmp(const struct sockaddr_storage *s1,
 597    const struct sockaddr_storage *s2)
 598{
 599        const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 600        const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 601
 602        if (sa1->sa_family != sa2->sa_family)
 603                return sa1->sa_family - sa2->sa_family;
 604        if (sa1->sa_family == AF_INET)
 605                return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 606                    &((struct sockaddr_in *)s2)->sin_addr,
 607                    sizeof(struct in_addr));
 608#ifndef NO_IPV6
 609        if (sa1->sa_family == AF_INET6)
 610                return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 611                    &((struct sockaddr_in6 *)s2)->sin6_addr,
 612                    sizeof(struct in6_addr));
 613#endif
 614        return 0;
 615}
 616
 617static int max_connections = 32;
 618
 619static unsigned int live_children;
 620
 621static struct child {
 622        struct child *next;
 623        pid_t pid;
 624        struct sockaddr_storage address;
 625} *firstborn;
 626
 627static void add_child(pid_t pid, struct sockaddr *addr, int addrlen)
 628{
 629        struct child *newborn, **cradle;
 630
 631        newborn = xcalloc(1, sizeof(*newborn));
 632        live_children++;
 633        newborn->pid = pid;
 634        memcpy(&newborn->address, addr, addrlen);
 635        for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 636                if (!addrcmp(&(*cradle)->address, &newborn->address))
 637                        break;
 638        newborn->next = *cradle;
 639        *cradle = newborn;
 640}
 641
 642static void remove_child(pid_t pid)
 643{
 644        struct child **cradle, *blanket;
 645
 646        for (cradle = &firstborn; (blanket = *cradle); cradle = &blanket->next)
 647                if (blanket->pid == pid) {
 648                        *cradle = blanket->next;
 649                        live_children--;
 650                        free(blanket);
 651                        break;
 652                }
 653}
 654
 655/*
 656 * This gets called if the number of connections grows
 657 * past "max_connections".
 658 *
 659 * We kill the newest connection from a duplicate IP.
 660 */
 661static void kill_some_child(void)
 662{
 663        const struct child *blanket, *next;
 664
 665        if (!(blanket = firstborn))
 666                return;
 667
 668        for (; (next = blanket->next); blanket = next)
 669                if (!addrcmp(&blanket->address, &next->address)) {
 670                        kill(blanket->pid, SIGTERM);
 671                        break;
 672                }
 673}
 674
 675static void check_dead_children(void)
 676{
 677        int status;
 678        pid_t pid;
 679
 680        while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
 681                const char *dead = "";
 682                remove_child(pid);
 683                if (!WIFEXITED(status) || (WEXITSTATUS(status) > 0))
 684                        dead = " (with error)";
 685                loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 686        }
 687}
 688
 689static void handle(int incoming, struct sockaddr *addr, int addrlen)
 690{
 691        pid_t pid;
 692
 693        if (max_connections && live_children >= max_connections) {
 694                kill_some_child();
 695                sleep(1);  /* give it some time to die */
 696                check_dead_children();
 697                if (live_children >= max_connections) {
 698                        close(incoming);
 699                        logerror("Too many children, dropping connection");
 700                        return;
 701                }
 702        }
 703
 704        if ((pid = fork())) {
 705                close(incoming);
 706                if (pid < 0) {
 707                        logerror("Couldn't fork %s", strerror(errno));
 708                        return;
 709                }
 710
 711                add_child(pid, addr, addrlen);
 712                return;
 713        }
 714
 715        dup2(incoming, 0);
 716        dup2(incoming, 1);
 717        close(incoming);
 718
 719        exit(execute(addr));
 720}
 721
 722static void child_handler(int signo)
 723{
 724        /*
 725         * Otherwise empty handler because systemcalls will get interrupted
 726         * upon signal receipt
 727         * SysV needs the handler to be rearmed
 728         */
 729        signal(SIGCHLD, child_handler);
 730}
 731
 732static int set_reuse_addr(int sockfd)
 733{
 734        int on = 1;
 735
 736        if (!reuseaddr)
 737                return 0;
 738        return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 739                          &on, sizeof(on));
 740}
 741
 742struct socketlist {
 743        int *list;
 744        size_t nr;
 745        size_t alloc;
 746};
 747
 748#ifndef NO_IPV6
 749
 750static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 751{
 752        int socknum = 0;
 753        int maxfd = -1;
 754        char pbuf[NI_MAXSERV];
 755        struct addrinfo hints, *ai0, *ai;
 756        int gai;
 757        long flags;
 758
 759        sprintf(pbuf, "%d", listen_port);
 760        memset(&hints, 0, sizeof(hints));
 761        hints.ai_family = AF_UNSPEC;
 762        hints.ai_socktype = SOCK_STREAM;
 763        hints.ai_protocol = IPPROTO_TCP;
 764        hints.ai_flags = AI_PASSIVE;
 765
 766        gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 767        if (gai) {
 768                logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
 769                return 0;
 770        }
 771
 772        for (ai = ai0; ai; ai = ai->ai_next) {
 773                int sockfd;
 774
 775                sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 776                if (sockfd < 0)
 777                        continue;
 778                if (sockfd >= FD_SETSIZE) {
 779                        logerror("Socket descriptor too large");
 780                        close(sockfd);
 781                        continue;
 782                }
 783
 784#ifdef IPV6_V6ONLY
 785                if (ai->ai_family == AF_INET6) {
 786                        int on = 1;
 787                        setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 788                                   &on, sizeof(on));
 789                        /* Note: error is not fatal */
 790                }
 791#endif
 792
 793                if (set_reuse_addr(sockfd)) {
 794                        close(sockfd);
 795                        continue;
 796                }
 797
 798                if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 799                        close(sockfd);
 800                        continue;       /* not fatal */
 801                }
 802                if (listen(sockfd, 5) < 0) {
 803                        close(sockfd);
 804                        continue;       /* not fatal */
 805                }
 806
 807                flags = fcntl(sockfd, F_GETFD, 0);
 808                if (flags >= 0)
 809                        fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 810
 811                ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 812                socklist->list[socklist->nr++] = sockfd;
 813                socknum++;
 814
 815                if (maxfd < sockfd)
 816                        maxfd = sockfd;
 817        }
 818
 819        freeaddrinfo(ai0);
 820
 821        return socknum;
 822}
 823
 824#else /* NO_IPV6 */
 825
 826static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 827{
 828        struct sockaddr_in sin;
 829        int sockfd;
 830        long flags;
 831
 832        memset(&sin, 0, sizeof sin);
 833        sin.sin_family = AF_INET;
 834        sin.sin_port = htons(listen_port);
 835
 836        if (listen_addr) {
 837                /* Well, host better be an IP address here. */
 838                if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 839                        return 0;
 840        } else {
 841                sin.sin_addr.s_addr = htonl(INADDR_ANY);
 842        }
 843
 844        sockfd = socket(AF_INET, SOCK_STREAM, 0);
 845        if (sockfd < 0)
 846                return 0;
 847
 848        if (set_reuse_addr(sockfd)) {
 849                close(sockfd);
 850                return 0;
 851        }
 852
 853        if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 854                close(sockfd);
 855                return 0;
 856        }
 857
 858        if (listen(sockfd, 5) < 0) {
 859                close(sockfd);
 860                return 0;
 861        }
 862
 863        flags = fcntl(sockfd, F_GETFD, 0);
 864        if (flags >= 0)
 865                fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 866
 867        ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 868        socklist->list[socklist->nr++] = sockfd;
 869        return 1;
 870}
 871
 872#endif
 873
 874static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
 875{
 876        if (!listen_addr->nr)
 877                setup_named_sock(NULL, listen_port, socklist);
 878        else {
 879                int i, socknum;
 880                for (i = 0; i < listen_addr->nr; i++) {
 881                        socknum = setup_named_sock(listen_addr->items[i].string,
 882                                                   listen_port, socklist);
 883
 884                        if (socknum == 0)
 885                                logerror("unable to allocate any listen sockets for host %s on port %u",
 886                                         listen_addr->items[i].string, listen_port);
 887                }
 888        }
 889}
 890
 891static int service_loop(struct socketlist *socklist)
 892{
 893        struct pollfd *pfd;
 894        int i;
 895
 896        pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
 897
 898        for (i = 0; i < socklist->nr; i++) {
 899                pfd[i].fd = socklist->list[i];
 900                pfd[i].events = POLLIN;
 901        }
 902
 903        signal(SIGCHLD, child_handler);
 904
 905        for (;;) {
 906                int i;
 907
 908                check_dead_children();
 909
 910                if (poll(pfd, socklist->nr, -1) < 0) {
 911                        if (errno != EINTR) {
 912                                logerror("Poll failed, resuming: %s",
 913                                      strerror(errno));
 914                                sleep(1);
 915                        }
 916                        continue;
 917                }
 918
 919                for (i = 0; i < socklist->nr; i++) {
 920                        if (pfd[i].revents & POLLIN) {
 921                                struct sockaddr_storage ss;
 922                                unsigned int sslen = sizeof(ss);
 923                                int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
 924                                if (incoming < 0) {
 925                                        switch (errno) {
 926                                        case EAGAIN:
 927                                        case EINTR:
 928                                        case ECONNABORTED:
 929                                                continue;
 930                                        default:
 931                                                die_errno("accept returned");
 932                                        }
 933                                }
 934                                handle(incoming, (struct sockaddr *)&ss, sslen);
 935                        }
 936                }
 937        }
 938}
 939
 940/* if any standard file descriptor is missing open it to /dev/null */
 941static void sanitize_stdfds(void)
 942{
 943        int fd = open("/dev/null", O_RDWR, 0);
 944        while (fd != -1 && fd < 2)
 945                fd = dup(fd);
 946        if (fd == -1)
 947                die_errno("open /dev/null or dup failed");
 948        if (fd > 2)
 949                close(fd);
 950}
 951
 952static void daemonize(void)
 953{
 954        switch (fork()) {
 955                case 0:
 956                        break;
 957                case -1:
 958                        die_errno("fork failed");
 959                default:
 960                        exit(0);
 961        }
 962        if (setsid() == -1)
 963                die_errno("setsid failed");
 964        close(0);
 965        close(1);
 966        close(2);
 967        sanitize_stdfds();
 968}
 969
 970static void store_pid(const char *path)
 971{
 972        FILE *f = fopen(path, "w");
 973        if (!f)
 974                die_errno("cannot open pid file '%s'", path);
 975        if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
 976                die_errno("failed to write pid file '%s'", path);
 977}
 978
 979static int serve(struct string_list *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
 980{
 981        struct socketlist socklist = { NULL, 0, 0 };
 982
 983        socksetup(listen_addr, listen_port, &socklist);
 984        if (socklist.nr == 0)
 985                die("unable to allocate any listen sockets on port %u",
 986                    listen_port);
 987
 988        if (pass && gid &&
 989            (initgroups(pass->pw_name, gid) || setgid (gid) ||
 990             setuid(pass->pw_uid)))
 991                die("cannot drop privileges");
 992
 993        return service_loop(&socklist);
 994}
 995
 996int main(int argc, char **argv)
 997{
 998        int listen_port = 0;
 999        struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1000        int inetd_mode = 0;
1001        const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1002        int detach = 0;
1003        struct passwd *pass = NULL;
1004        struct group *group;
1005        gid_t gid = 0;
1006        int i;
1007
1008        git_extract_argv0_path(argv[0]);
1009
1010        for (i = 1; i < argc; i++) {
1011                char *arg = argv[i];
1012
1013                if (!prefixcmp(arg, "--listen=")) {
1014                        string_list_append(&listen_addr, xstrdup_tolower(arg + 9));
1015                        continue;
1016                }
1017                if (!prefixcmp(arg, "--port=")) {
1018                        char *end;
1019                        unsigned long n;
1020                        n = strtoul(arg+7, &end, 0);
1021                        if (arg[7] && !*end) {
1022                                listen_port = n;
1023                                continue;
1024                        }
1025                }
1026                if (!strcmp(arg, "--inetd")) {
1027                        inetd_mode = 1;
1028                        log_syslog = 1;
1029                        continue;
1030                }
1031                if (!strcmp(arg, "--verbose")) {
1032                        verbose = 1;
1033                        continue;
1034                }
1035                if (!strcmp(arg, "--syslog")) {
1036                        log_syslog = 1;
1037                        continue;
1038                }
1039                if (!strcmp(arg, "--export-all")) {
1040                        export_all_trees = 1;
1041                        continue;
1042                }
1043                if (!prefixcmp(arg, "--timeout=")) {
1044                        timeout = atoi(arg+10);
1045                        continue;
1046                }
1047                if (!prefixcmp(arg, "--init-timeout=")) {
1048                        init_timeout = atoi(arg+15);
1049                        continue;
1050                }
1051                if (!prefixcmp(arg, "--max-connections=")) {
1052                        max_connections = atoi(arg+18);
1053                        if (max_connections < 0)
1054                                max_connections = 0;            /* unlimited */
1055                        continue;
1056                }
1057                if (!strcmp(arg, "--strict-paths")) {
1058                        strict_paths = 1;
1059                        continue;
1060                }
1061                if (!prefixcmp(arg, "--base-path=")) {
1062                        base_path = arg+12;
1063                        continue;
1064                }
1065                if (!strcmp(arg, "--base-path-relaxed")) {
1066                        base_path_relaxed = 1;
1067                        continue;
1068                }
1069                if (!prefixcmp(arg, "--interpolated-path=")) {
1070                        interpolated_path = arg+20;
1071                        continue;
1072                }
1073                if (!strcmp(arg, "--reuseaddr")) {
1074                        reuseaddr = 1;
1075                        continue;
1076                }
1077                if (!strcmp(arg, "--user-path")) {
1078                        user_path = "";
1079                        continue;
1080                }
1081                if (!prefixcmp(arg, "--user-path=")) {
1082                        user_path = arg + 12;
1083                        continue;
1084                }
1085                if (!prefixcmp(arg, "--pid-file=")) {
1086                        pid_file = arg + 11;
1087                        continue;
1088                }
1089                if (!strcmp(arg, "--detach")) {
1090                        detach = 1;
1091                        log_syslog = 1;
1092                        continue;
1093                }
1094                if (!prefixcmp(arg, "--user=")) {
1095                        user_name = arg + 7;
1096                        continue;
1097                }
1098                if (!prefixcmp(arg, "--group=")) {
1099                        group_name = arg + 8;
1100                        continue;
1101                }
1102                if (!prefixcmp(arg, "--enable=")) {
1103                        enable_service(arg + 9, 1);
1104                        continue;
1105                }
1106                if (!prefixcmp(arg, "--disable=")) {
1107                        enable_service(arg + 10, 0);
1108                        continue;
1109                }
1110                if (!prefixcmp(arg, "--allow-override=")) {
1111                        make_service_overridable(arg + 17, 1);
1112                        continue;
1113                }
1114                if (!prefixcmp(arg, "--forbid-override=")) {
1115                        make_service_overridable(arg + 18, 0);
1116                        continue;
1117                }
1118                if (!strcmp(arg, "--")) {
1119                        ok_paths = &argv[i+1];
1120                        break;
1121                } else if (arg[0] != '-') {
1122                        ok_paths = &argv[i];
1123                        break;
1124                }
1125
1126                usage(daemon_usage);
1127        }
1128
1129        if (log_syslog) {
1130                openlog("git-daemon", LOG_PID, LOG_DAEMON);
1131                set_die_routine(daemon_die);
1132        } else
1133                /* avoid splitting a message in the middle */
1134                setvbuf(stderr, NULL, _IOLBF, 0);
1135
1136        if (inetd_mode && (group_name || user_name))
1137                die("--user and --group are incompatible with --inetd");
1138
1139        if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1140                die("--listen= and --port= are incompatible with --inetd");
1141        else if (listen_port == 0)
1142                listen_port = DEFAULT_GIT_PORT;
1143
1144        if (group_name && !user_name)
1145                die("--group supplied without --user");
1146
1147        if (user_name) {
1148                pass = getpwnam(user_name);
1149                if (!pass)
1150                        die("user not found - %s", user_name);
1151
1152                if (!group_name)
1153                        gid = pass->pw_gid;
1154                else {
1155                        group = getgrnam(group_name);
1156                        if (!group)
1157                                die("group not found - %s", group_name);
1158
1159                        gid = group->gr_gid;
1160                }
1161        }
1162
1163        if (strict_paths && (!ok_paths || !*ok_paths))
1164                die("option --strict-paths requires a whitelist");
1165
1166        if (base_path && !is_directory(base_path))
1167                die("base-path '%s' does not exist or is not a directory",
1168                    base_path);
1169
1170        if (inetd_mode) {
1171                struct sockaddr_storage ss;
1172                struct sockaddr *peer = (struct sockaddr *)&ss;
1173                socklen_t slen = sizeof(ss);
1174
1175                if (!freopen("/dev/null", "w", stderr))
1176                        die_errno("failed to redirect stderr to /dev/null");
1177
1178                if (getpeername(0, peer, &slen))
1179                        peer = NULL;
1180
1181                return execute(peer);
1182        }
1183
1184        if (detach) {
1185                daemonize();
1186                loginfo("Ready to rumble");
1187        }
1188        else
1189                sanitize_stdfds();
1190
1191        if (pid_file)
1192                store_pid(pid_file);
1193
1194        return serve(&listen_addr, listen_port, pass, gid);
1195}