Andrew's git / gitweb.git / daemon.c
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daemon.con commit ll-merge.c: refactor `read_merge_config()` to use `git_config_string()` (6ea358f)
   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 const char *base_path;
  43static const 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(const char *directory)
 110{
 111        static char rpath[PATH_MAX];
 112        static char interp_path[PATH_MAX];
 113        const char *path;
 114        const 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                        const 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 int daemon_error(const char *dir, const char *msg)
 234{
 235        if (!informative_errors)
 236                msg = "access denied or repository not exported";
 237        packet_write(1, "ERR %s: %s", msg, dir);
 238        return -1;
 239}
 240
 241static const char *access_hook;
 242
 243static int run_access_hook(struct daemon_service *service, const char *dir, const char *path)
 244{
 245        struct child_process child;
 246        struct strbuf buf = STRBUF_INIT;
 247        const char *argv[8];
 248        const char **arg = argv;
 249        char *eol;
 250        int seen_errors = 0;
 251
 252#define STRARG(x) ((x) ? (x) : "")
 253        *arg++ = access_hook;
 254        *arg++ = service->name;
 255        *arg++ = path;
 256        *arg++ = STRARG(hostname);
 257        *arg++ = STRARG(canon_hostname);
 258        *arg++ = STRARG(ip_address);
 259        *arg++ = STRARG(tcp_port);
 260        *arg = NULL;
 261#undef STRARG
 262
 263        memset(&child, 0, sizeof(child));
 264        child.use_shell = 1;
 265        child.argv = argv;
 266        child.no_stdin = 1;
 267        child.no_stderr = 1;
 268        child.out = -1;
 269        if (start_command(&child)) {
 270                logerror("daemon access hook '%s' failed to start",
 271                         access_hook);
 272                goto error_return;
 273        }
 274        if (strbuf_read(&buf, child.out, 0) < 0) {
 275                logerror("failed to read from pipe to daemon access hook '%s'",
 276                         access_hook);
 277                strbuf_reset(&buf);
 278                seen_errors = 1;
 279        }
 280        if (close(child.out) < 0) {
 281                logerror("failed to close pipe to daemon access hook '%s'",
 282                         access_hook);
 283                seen_errors = 1;
 284        }
 285        if (finish_command(&child))
 286                seen_errors = 1;
 287
 288        if (!seen_errors) {
 289                strbuf_release(&buf);
 290                return 0;
 291        }
 292
 293error_return:
 294        strbuf_ltrim(&buf);
 295        if (!buf.len)
 296                strbuf_addstr(&buf, "service rejected");
 297        eol = strchr(buf.buf, '\n');
 298        if (eol)
 299                *eol = '\0';
 300        errno = EACCES;
 301        daemon_error(dir, buf.buf);
 302        strbuf_release(&buf);
 303        return -1;
 304}
 305
 306static int run_service(const char *dir, struct daemon_service *service)
 307{
 308        const char *path;
 309        int enabled = service->enabled;
 310        struct strbuf var = STRBUF_INIT;
 311
 312        loginfo("Request %s for '%s'", service->name, dir);
 313
 314        if (!enabled && !service->overridable) {
 315                logerror("'%s': service not enabled.", service->name);
 316                errno = EACCES;
 317                return daemon_error(dir, "service not enabled");
 318        }
 319
 320        if (!(path = path_ok(dir)))
 321                return daemon_error(dir, "no such repository");
 322
 323        /*
 324         * Security on the cheap.
 325         *
 326         * We want a readable HEAD, usable "objects" directory, and
 327         * a "git-daemon-export-ok" flag that says that the other side
 328         * is ok with us doing this.
 329         *
 330         * path_ok() uses enter_repo() and does whitelist checking.
 331         * We only need to make sure the repository is exported.
 332         */
 333
 334        if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 335                logerror("'%s': repository not exported.", path);
 336                errno = EACCES;
 337                return daemon_error(dir, "repository not exported");
 338        }
 339
 340        if (service->overridable) {
 341                strbuf_addf(&var, "daemon.%s", service->config_name);
 342                git_config_get_bool(var.buf, &enabled);
 343                strbuf_release(&var);
 344        }
 345        if (!enabled) {
 346                logerror("'%s': service not enabled for '%s'",
 347                         service->name, path);
 348                errno = EACCES;
 349                return daemon_error(dir, "service not enabled");
 350        }
 351
 352        /*
 353         * Optionally, a hook can choose to deny access to the
 354         * repository depending on the phase of the moon.
 355         */
 356        if (access_hook && run_access_hook(service, dir, path))
 357                return -1;
 358
 359        /*
 360         * We'll ignore SIGTERM from now on, we have a
 361         * good client.
 362         */
 363        signal(SIGTERM, SIG_IGN);
 364
 365        return service->fn();
 366}
 367
 368static void copy_to_log(int fd)
 369{
 370        struct strbuf line = STRBUF_INIT;
 371        FILE *fp;
 372
 373        fp = fdopen(fd, "r");
 374        if (fp == NULL) {
 375                logerror("fdopen of error channel failed");
 376                close(fd);
 377                return;
 378        }
 379
 380        while (strbuf_getline(&line, fp, '\n') != EOF) {
 381                logerror("%s", line.buf);
 382                strbuf_setlen(&line, 0);
 383        }
 384
 385        strbuf_release(&line);
 386        fclose(fp);
 387}
 388
 389static int run_service_command(const char **argv)
 390{
 391        struct child_process cld;
 392
 393        memset(&cld, 0, sizeof(cld));
 394        cld.argv = argv;
 395        cld.git_cmd = 1;
 396        cld.err = -1;
 397        if (start_command(&cld))
 398                return -1;
 399
 400        close(0);
 401        close(1);
 402
 403        copy_to_log(cld.err);
 404
 405        return finish_command(&cld);
 406}
 407
 408static int upload_pack(void)
 409{
 410        /* Timeout as string */
 411        char timeout_buf[64];
 412        const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
 413
 414        argv[2] = timeout_buf;
 415
 416        snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 417        return run_service_command(argv);
 418}
 419
 420static int upload_archive(void)
 421{
 422        static const char *argv[] = { "upload-archive", ".", NULL };
 423        return run_service_command(argv);
 424}
 425
 426static int receive_pack(void)
 427{
 428        static const char *argv[] = { "receive-pack", ".", NULL };
 429        return run_service_command(argv);
 430}
 431
 432static struct daemon_service daemon_service[] = {
 433        { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 434        { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 435        { "receive-pack", "receivepack", receive_pack, 0, 1 },
 436};
 437
 438static void enable_service(const char *name, int ena)
 439{
 440        int i;
 441        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 442                if (!strcmp(daemon_service[i].name, name)) {
 443                        daemon_service[i].enabled = ena;
 444                        return;
 445                }
 446        }
 447        die("No such service %s", name);
 448}
 449
 450static void make_service_overridable(const char *name, int ena)
 451{
 452        int i;
 453        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 454                if (!strcmp(daemon_service[i].name, name)) {
 455                        daemon_service[i].overridable = ena;
 456                        return;
 457                }
 458        }
 459        die("No such service %s", name);
 460}
 461
 462static void parse_host_and_port(char *hostport, char **host,
 463        char **port)
 464{
 465        if (*hostport == '[') {
 466                char *end;
 467
 468                end = strchr(hostport, ']');
 469                if (!end)
 470                        die("Invalid request ('[' without ']')");
 471                *end = '\0';
 472                *host = hostport + 1;
 473                if (!end[1])
 474                        *port = NULL;
 475                else if (end[1] == ':')
 476                        *port = end + 2;
 477                else
 478                        die("Garbage after end of host part");
 479        } else {
 480                *host = hostport;
 481                *port = strrchr(hostport, ':');
 482                if (*port) {
 483                        **port = '\0';
 484                        ++*port;
 485                }
 486        }
 487}
 488
 489/*
 490 * Read the host as supplied by the client connection.
 491 */
 492static void parse_host_arg(char *extra_args, int buflen)
 493{
 494        char *val;
 495        int vallen;
 496        char *end = extra_args + buflen;
 497
 498        if (extra_args < end && *extra_args) {
 499                saw_extended_args = 1;
 500                if (strncasecmp("host=", extra_args, 5) == 0) {
 501                        val = extra_args + 5;
 502                        vallen = strlen(val) + 1;
 503                        if (*val) {
 504                                /* Split <host>:<port> at colon. */
 505                                char *host;
 506                                char *port;
 507                                parse_host_and_port(val, &host, &port);
 508                                if (port) {
 509                                        free(tcp_port);
 510                                        tcp_port = xstrdup(port);
 511                                }
 512                                free(hostname);
 513                                hostname = xstrdup_tolower(host);
 514                        }
 515
 516                        /* On to the next one */
 517                        extra_args = val + vallen;
 518                }
 519                if (extra_args < end && *extra_args)
 520                        die("Invalid request");
 521        }
 522
 523        /*
 524         * Locate canonical hostname and its IP address.
 525         */
 526        if (hostname) {
 527#ifndef NO_IPV6
 528                struct addrinfo hints;
 529                struct addrinfo *ai;
 530                int gai;
 531                static char addrbuf[HOST_NAME_MAX + 1];
 532
 533                memset(&hints, 0, sizeof(hints));
 534                hints.ai_flags = AI_CANONNAME;
 535
 536                gai = getaddrinfo(hostname, NULL, &hints, &ai);
 537                if (!gai) {
 538                        struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 539
 540                        inet_ntop(AF_INET, &sin_addr->sin_addr,
 541                                  addrbuf, sizeof(addrbuf));
 542                        free(ip_address);
 543                        ip_address = xstrdup(addrbuf);
 544
 545                        free(canon_hostname);
 546                        canon_hostname = xstrdup(ai->ai_canonname ?
 547                                                 ai->ai_canonname : ip_address);
 548
 549                        freeaddrinfo(ai);
 550                }
 551#else
 552                struct hostent *hent;
 553                struct sockaddr_in sa;
 554                char **ap;
 555                static char addrbuf[HOST_NAME_MAX + 1];
 556
 557                hent = gethostbyname(hostname);
 558
 559                ap = hent->h_addr_list;
 560                memset(&sa, 0, sizeof sa);
 561                sa.sin_family = hent->h_addrtype;
 562                sa.sin_port = htons(0);
 563                memcpy(&sa.sin_addr, *ap, hent->h_length);
 564
 565                inet_ntop(hent->h_addrtype, &sa.sin_addr,
 566                          addrbuf, sizeof(addrbuf));
 567
 568                free(canon_hostname);
 569                canon_hostname = xstrdup(hent->h_name);
 570                free(ip_address);
 571                ip_address = xstrdup(addrbuf);
 572#endif
 573        }
 574}
 575
 576
 577static int execute(void)
 578{
 579        char *line = packet_buffer;
 580        int pktlen, len, i;
 581        char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
 582
 583        if (addr)
 584                loginfo("Connection from %s:%s", addr, port);
 585
 586        alarm(init_timeout ? init_timeout : timeout);
 587        pktlen = packet_read(0, NULL, NULL, packet_buffer, sizeof(packet_buffer), 0);
 588        alarm(0);
 589
 590        len = strlen(line);
 591        if (pktlen != len)
 592                loginfo("Extended attributes (%d bytes) exist <%.*s>",
 593                        (int) pktlen - len,
 594                        (int) pktlen - len, line + len + 1);
 595        if (len && line[len-1] == '\n') {
 596                line[--len] = 0;
 597                pktlen--;
 598        }
 599
 600        free(hostname);
 601        free(canon_hostname);
 602        free(ip_address);
 603        free(tcp_port);
 604        hostname = canon_hostname = ip_address = tcp_port = NULL;
 605
 606        if (len != pktlen)
 607                parse_host_arg(line + len + 1, pktlen - len - 1);
 608
 609        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 610                struct daemon_service *s = &(daemon_service[i]);
 611                const char *arg;
 612
 613                if (skip_prefix(line, "git-", &arg) &&
 614                    skip_prefix(arg, s->name, &arg) &&
 615                    *arg++ == ' ') {
 616                        /*
 617                         * Note: The directory here is probably context sensitive,
 618                         * and might depend on the actual service being performed.
 619                         */
 620                        return run_service(arg, s);
 621                }
 622        }
 623
 624        logerror("Protocol error: '%s'", line);
 625        return -1;
 626}
 627
 628static int addrcmp(const struct sockaddr_storage *s1,
 629    const struct sockaddr_storage *s2)
 630{
 631        const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 632        const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 633
 634        if (sa1->sa_family != sa2->sa_family)
 635                return sa1->sa_family - sa2->sa_family;
 636        if (sa1->sa_family == AF_INET)
 637                return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 638                    &((struct sockaddr_in *)s2)->sin_addr,
 639                    sizeof(struct in_addr));
 640#ifndef NO_IPV6
 641        if (sa1->sa_family == AF_INET6)
 642                return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 643                    &((struct sockaddr_in6 *)s2)->sin6_addr,
 644                    sizeof(struct in6_addr));
 645#endif
 646        return 0;
 647}
 648
 649static int max_connections = 32;
 650
 651static unsigned int live_children;
 652
 653static struct child {
 654        struct child *next;
 655        struct child_process cld;
 656        struct sockaddr_storage address;
 657} *firstborn;
 658
 659static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
 660{
 661        struct child *newborn, **cradle;
 662
 663        newborn = xcalloc(1, sizeof(*newborn));
 664        live_children++;
 665        memcpy(&newborn->cld, cld, sizeof(*cld));
 666        memcpy(&newborn->address, addr, addrlen);
 667        for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 668                if (!addrcmp(&(*cradle)->address, &newborn->address))
 669                        break;
 670        newborn->next = *cradle;
 671        *cradle = newborn;
 672}
 673
 674/*
 675 * This gets called if the number of connections grows
 676 * past "max_connections".
 677 *
 678 * We kill the newest connection from a duplicate IP.
 679 */
 680static void kill_some_child(void)
 681{
 682        const struct child *blanket, *next;
 683
 684        if (!(blanket = firstborn))
 685                return;
 686
 687        for (; (next = blanket->next); blanket = next)
 688                if (!addrcmp(&blanket->address, &next->address)) {
 689                        kill(blanket->cld.pid, SIGTERM);
 690                        break;
 691                }
 692}
 693
 694static void check_dead_children(void)
 695{
 696        int status;
 697        pid_t pid;
 698
 699        struct child **cradle, *blanket;
 700        for (cradle = &firstborn; (blanket = *cradle);)
 701                if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
 702                        const char *dead = "";
 703                        if (status)
 704                                dead = " (with error)";
 705                        loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 706
 707                        /* remove the child */
 708                        *cradle = blanket->next;
 709                        live_children--;
 710                        free(blanket);
 711                } else
 712                        cradle = &blanket->next;
 713}
 714
 715static char **cld_argv;
 716static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 717{
 718        struct child_process cld = { NULL };
 719        char addrbuf[300] = "REMOTE_ADDR=", portbuf[300];
 720        char *env[] = { addrbuf, portbuf, NULL };
 721
 722        if (max_connections && live_children >= max_connections) {
 723                kill_some_child();
 724                sleep(1);  /* give it some time to die */
 725                check_dead_children();
 726                if (live_children >= max_connections) {
 727                        close(incoming);
 728                        logerror("Too many children, dropping connection");
 729                        return;
 730                }
 731        }
 732
 733        if (addr->sa_family == AF_INET) {
 734                struct sockaddr_in *sin_addr = (void *) addr;
 735                inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf + 12,
 736                    sizeof(addrbuf) - 12);
 737                snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 738                    ntohs(sin_addr->sin_port));
 739#ifndef NO_IPV6
 740        } else if (addr->sa_family == AF_INET6) {
 741                struct sockaddr_in6 *sin6_addr = (void *) addr;
 742
 743                char *buf = addrbuf + 12;
 744                *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 745                inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf,
 746                    sizeof(addrbuf) - 13);
 747                strcat(buf, "]");
 748
 749                snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 750                    ntohs(sin6_addr->sin6_port));
 751#endif
 752        }
 753
 754        cld.env = (const char **)env;
 755        cld.argv = (const char **)cld_argv;
 756        cld.in = incoming;
 757        cld.out = dup(incoming);
 758
 759        if (start_command(&cld))
 760                logerror("unable to fork");
 761        else
 762                add_child(&cld, addr, addrlen);
 763}
 764
 765static void child_handler(int signo)
 766{
 767        /*
 768         * Otherwise empty handler because systemcalls will get interrupted
 769         * upon signal receipt
 770         * SysV needs the handler to be rearmed
 771         */
 772        signal(SIGCHLD, child_handler);
 773}
 774
 775static int set_reuse_addr(int sockfd)
 776{
 777        int on = 1;
 778
 779        if (!reuseaddr)
 780                return 0;
 781        return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 782                          &on, sizeof(on));
 783}
 784
 785struct socketlist {
 786        int *list;
 787        size_t nr;
 788        size_t alloc;
 789};
 790
 791static const char *ip2str(int family, struct sockaddr *sin, socklen_t len)
 792{
 793#ifdef NO_IPV6
 794        static char ip[INET_ADDRSTRLEN];
 795#else
 796        static char ip[INET6_ADDRSTRLEN];
 797#endif
 798
 799        switch (family) {
 800#ifndef NO_IPV6
 801        case AF_INET6:
 802                inet_ntop(family, &((struct sockaddr_in6*)sin)->sin6_addr, ip, len);
 803                break;
 804#endif
 805        case AF_INET:
 806                inet_ntop(family, &((struct sockaddr_in*)sin)->sin_addr, ip, len);
 807                break;
 808        default:
 809                strcpy(ip, "<unknown>");
 810        }
 811        return ip;
 812}
 813
 814#ifndef NO_IPV6
 815
 816static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 817{
 818        int socknum = 0;
 819        int maxfd = -1;
 820        char pbuf[NI_MAXSERV];
 821        struct addrinfo hints, *ai0, *ai;
 822        int gai;
 823        long flags;
 824
 825        sprintf(pbuf, "%d", listen_port);
 826        memset(&hints, 0, sizeof(hints));
 827        hints.ai_family = AF_UNSPEC;
 828        hints.ai_socktype = SOCK_STREAM;
 829        hints.ai_protocol = IPPROTO_TCP;
 830        hints.ai_flags = AI_PASSIVE;
 831
 832        gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 833        if (gai) {
 834                logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
 835                return 0;
 836        }
 837
 838        for (ai = ai0; ai; ai = ai->ai_next) {
 839                int sockfd;
 840
 841                sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 842                if (sockfd < 0)
 843                        continue;
 844                if (sockfd >= FD_SETSIZE) {
 845                        logerror("Socket descriptor too large");
 846                        close(sockfd);
 847                        continue;
 848                }
 849
 850#ifdef IPV6_V6ONLY
 851                if (ai->ai_family == AF_INET6) {
 852                        int on = 1;
 853                        setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 854                                   &on, sizeof(on));
 855                        /* Note: error is not fatal */
 856                }
 857#endif
 858
 859                if (set_reuse_addr(sockfd)) {
 860                        logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 861                        close(sockfd);
 862                        continue;
 863                }
 864
 865                if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 866                        logerror("Could not bind to %s: %s",
 867                                 ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 868                                 strerror(errno));
 869                        close(sockfd);
 870                        continue;       /* not fatal */
 871                }
 872                if (listen(sockfd, 5) < 0) {
 873                        logerror("Could not listen to %s: %s",
 874                                 ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 875                                 strerror(errno));
 876                        close(sockfd);
 877                        continue;       /* not fatal */
 878                }
 879
 880                flags = fcntl(sockfd, F_GETFD, 0);
 881                if (flags >= 0)
 882                        fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 883
 884                ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 885                socklist->list[socklist->nr++] = sockfd;
 886                socknum++;
 887
 888                if (maxfd < sockfd)
 889                        maxfd = sockfd;
 890        }
 891
 892        freeaddrinfo(ai0);
 893
 894        return socknum;
 895}
 896
 897#else /* NO_IPV6 */
 898
 899static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 900{
 901        struct sockaddr_in sin;
 902        int sockfd;
 903        long flags;
 904
 905        memset(&sin, 0, sizeof sin);
 906        sin.sin_family = AF_INET;
 907        sin.sin_port = htons(listen_port);
 908
 909        if (listen_addr) {
 910                /* Well, host better be an IP address here. */
 911                if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 912                        return 0;
 913        } else {
 914                sin.sin_addr.s_addr = htonl(INADDR_ANY);
 915        }
 916
 917        sockfd = socket(AF_INET, SOCK_STREAM, 0);
 918        if (sockfd < 0)
 919                return 0;
 920
 921        if (set_reuse_addr(sockfd)) {
 922                logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 923                close(sockfd);
 924                return 0;
 925        }
 926
 927        if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 928                logerror("Could not listen to %s: %s",
 929                         ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
 930                         strerror(errno));
 931                close(sockfd);
 932                return 0;
 933        }
 934
 935        if (listen(sockfd, 5) < 0) {
 936                logerror("Could not listen to %s: %s",
 937                         ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
 938                         strerror(errno));
 939                close(sockfd);
 940                return 0;
 941        }
 942
 943        flags = fcntl(sockfd, F_GETFD, 0);
 944        if (flags >= 0)
 945                fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 946
 947        ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 948        socklist->list[socklist->nr++] = sockfd;
 949        return 1;
 950}
 951
 952#endif
 953
 954static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
 955{
 956        if (!listen_addr->nr)
 957                setup_named_sock(NULL, listen_port, socklist);
 958        else {
 959                int i, socknum;
 960                for (i = 0; i < listen_addr->nr; i++) {
 961                        socknum = setup_named_sock(listen_addr->items[i].string,
 962                                                   listen_port, socklist);
 963
 964                        if (socknum == 0)
 965                                logerror("unable to allocate any listen sockets for host %s on port %u",
 966                                         listen_addr->items[i].string, listen_port);
 967                }
 968        }
 969}
 970
 971static int service_loop(struct socketlist *socklist)
 972{
 973        struct pollfd *pfd;
 974        int i;
 975
 976        pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
 977
 978        for (i = 0; i < socklist->nr; i++) {
 979                pfd[i].fd = socklist->list[i];
 980                pfd[i].events = POLLIN;
 981        }
 982
 983        signal(SIGCHLD, child_handler);
 984
 985        for (;;) {
 986                int i;
 987
 988                check_dead_children();
 989
 990                if (poll(pfd, socklist->nr, -1) < 0) {
 991                        if (errno != EINTR) {
 992                                logerror("Poll failed, resuming: %s",
 993                                      strerror(errno));
 994                                sleep(1);
 995                        }
 996                        continue;
 997                }
 998
 999                for (i = 0; i < socklist->nr; i++) {
1000                        if (pfd[i].revents & POLLIN) {
1001                                union {
1002                                        struct sockaddr sa;
1003                                        struct sockaddr_in sai;
1004#ifndef NO_IPV6
1005                                        struct sockaddr_in6 sai6;
1006#endif
1007                                } ss;
1008                                socklen_t sslen = sizeof(ss);
1009                                int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
1010                                if (incoming < 0) {
1011                                        switch (errno) {
1012                                        case EAGAIN:
1013                                        case EINTR:
1014                                        case ECONNABORTED:
1015                                                continue;
1016                                        default:
1017                                                die_errno("accept returned");
1018                                        }
1019                                }
1020                                handle(incoming, &ss.sa, sslen);
1021                        }
1022                }
1023        }
1024}
1025
1026#ifdef NO_POSIX_GOODIES
1027
1028struct credentials;
1029
1030static void drop_privileges(struct credentials *cred)
1031{
1032        /* nothing */
1033}
1034
1035static struct credentials *prepare_credentials(const char *user_name,
1036    const char *group_name)
1037{
1038        die("--user not supported on this platform");
1039}
1040
1041#else
1042
1043struct credentials {
1044        struct passwd *pass;
1045        gid_t gid;
1046};
1047
1048static void drop_privileges(struct credentials *cred)
1049{
1050        if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
1051            setgid (cred->gid) || setuid(cred->pass->pw_uid)))
1052                die("cannot drop privileges");
1053}
1054
1055static struct credentials *prepare_credentials(const char *user_name,
1056    const char *group_name)
1057{
1058        static struct credentials c;
1059
1060        c.pass = getpwnam(user_name);
1061        if (!c.pass)
1062                die("user not found - %s", user_name);
1063
1064        if (!group_name)
1065                c.gid = c.pass->pw_gid;
1066        else {
1067                struct group *group = getgrnam(group_name);
1068                if (!group)
1069                        die("group not found - %s", group_name);
1070
1071                c.gid = group->gr_gid;
1072        }
1073
1074        return &c;
1075}
1076#endif
1077
1078static void store_pid(const char *path)
1079{
1080        FILE *f = fopen(path, "w");
1081        if (!f)
1082                die_errno("cannot open pid file '%s'", path);
1083        if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
1084                die_errno("failed to write pid file '%s'", path);
1085}
1086
1087static int serve(struct string_list *listen_addr, int listen_port,
1088    struct credentials *cred)
1089{
1090        struct socketlist socklist = { NULL, 0, 0 };
1091
1092        socksetup(listen_addr, listen_port, &socklist);
1093        if (socklist.nr == 0)
1094                die("unable to allocate any listen sockets on port %u",
1095                    listen_port);
1096
1097        drop_privileges(cred);
1098
1099        loginfo("Ready to rumble");
1100
1101        return service_loop(&socklist);
1102}
1103
1104int main(int argc, char **argv)
1105{
1106        int listen_port = 0;
1107        struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1108        int serve_mode = 0, inetd_mode = 0;
1109        const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1110        int detach = 0;
1111        struct credentials *cred = NULL;
1112        int i;
1113
1114        git_setup_gettext();
1115
1116        git_extract_argv0_path(argv[0]);
1117
1118        for (i = 1; i < argc; i++) {
1119                char *arg = argv[i];
1120                const char *v;
1121
1122                if (skip_prefix(arg, "--listen=", &v)) {
1123                        string_list_append(&listen_addr, xstrdup_tolower(v));
1124                        continue;
1125                }
1126                if (skip_prefix(arg, "--port=", &v)) {
1127                        char *end;
1128                        unsigned long n;
1129                        n = strtoul(v, &end, 0);
1130                        if (*v && !*end) {
1131                                listen_port = n;
1132                                continue;
1133                        }
1134                }
1135                if (!strcmp(arg, "--serve")) {
1136                        serve_mode = 1;
1137                        continue;
1138                }
1139                if (!strcmp(arg, "--inetd")) {
1140                        inetd_mode = 1;
1141                        log_syslog = 1;
1142                        continue;
1143                }
1144                if (!strcmp(arg, "--verbose")) {
1145                        verbose = 1;
1146                        continue;
1147                }
1148                if (!strcmp(arg, "--syslog")) {
1149                        log_syslog = 1;
1150                        continue;
1151                }
1152                if (!strcmp(arg, "--export-all")) {
1153                        export_all_trees = 1;
1154                        continue;
1155                }
1156                if (skip_prefix(arg, "--access-hook=", &v)) {
1157                        access_hook = v;
1158                        continue;
1159                }
1160                if (skip_prefix(arg, "--timeout=", &v)) {
1161                        timeout = atoi(v);
1162                        continue;
1163                }
1164                if (skip_prefix(arg, "--init-timeout=", &v)) {
1165                        init_timeout = atoi(v);
1166                        continue;
1167                }
1168                if (skip_prefix(arg, "--max-connections=", &v)) {
1169                        max_connections = atoi(v);
1170                        if (max_connections < 0)
1171                                max_connections = 0;            /* unlimited */
1172                        continue;
1173                }
1174                if (!strcmp(arg, "--strict-paths")) {
1175                        strict_paths = 1;
1176                        continue;
1177                }
1178                if (skip_prefix(arg, "--base-path=", &v)) {
1179                        base_path = v;
1180                        continue;
1181                }
1182                if (!strcmp(arg, "--base-path-relaxed")) {
1183                        base_path_relaxed = 1;
1184                        continue;
1185                }
1186                if (skip_prefix(arg, "--interpolated-path=", &v)) {
1187                        interpolated_path = v;
1188                        continue;
1189                }
1190                if (!strcmp(arg, "--reuseaddr")) {
1191                        reuseaddr = 1;
1192                        continue;
1193                }
1194                if (!strcmp(arg, "--user-path")) {
1195                        user_path = "";
1196                        continue;
1197                }
1198                if (skip_prefix(arg, "--user-path=", &v)) {
1199                        user_path = v;
1200                        continue;
1201                }
1202                if (skip_prefix(arg, "--pid-file=", &v)) {
1203                        pid_file = v;
1204                        continue;
1205                }
1206                if (!strcmp(arg, "--detach")) {
1207                        detach = 1;
1208                        log_syslog = 1;
1209                        continue;
1210                }
1211                if (skip_prefix(arg, "--user=", &v)) {
1212                        user_name = v;
1213                        continue;
1214                }
1215                if (skip_prefix(arg, "--group=", &v)) {
1216                        group_name = v;
1217                        continue;
1218                }
1219                if (skip_prefix(arg, "--enable=", &v)) {
1220                        enable_service(v, 1);
1221                        continue;
1222                }
1223                if (skip_prefix(arg, "--disable=", &v)) {
1224                        enable_service(v, 0);
1225                        continue;
1226                }
1227                if (skip_prefix(arg, "--allow-override=", &v)) {
1228                        make_service_overridable(v, 1);
1229                        continue;
1230                }
1231                if (skip_prefix(arg, "--forbid-override=", &v)) {
1232                        make_service_overridable(v, 0);
1233                        continue;
1234                }
1235                if (!strcmp(arg, "--informative-errors")) {
1236                        informative_errors = 1;
1237                        continue;
1238                }
1239                if (!strcmp(arg, "--no-informative-errors")) {
1240                        informative_errors = 0;
1241                        continue;
1242                }
1243                if (!strcmp(arg, "--")) {
1244                        ok_paths = &argv[i+1];
1245                        break;
1246                } else if (arg[0] != '-') {
1247                        ok_paths = &argv[i];
1248                        break;
1249                }
1250
1251                usage(daemon_usage);
1252        }
1253
1254        if (log_syslog) {
1255                openlog("git-daemon", LOG_PID, LOG_DAEMON);
1256                set_die_routine(daemon_die);
1257        } else
1258                /* avoid splitting a message in the middle */
1259                setvbuf(stderr, NULL, _IOFBF, 4096);
1260
1261        if (inetd_mode && (detach || group_name || user_name))
1262                die("--detach, --user and --group are incompatible with --inetd");
1263
1264        if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1265                die("--listen= and --port= are incompatible with --inetd");
1266        else if (listen_port == 0)
1267                listen_port = DEFAULT_GIT_PORT;
1268
1269        if (group_name && !user_name)
1270                die("--group supplied without --user");
1271
1272        if (user_name)
1273                cred = prepare_credentials(user_name, group_name);
1274
1275        if (strict_paths && (!ok_paths || !*ok_paths))
1276                die("option --strict-paths requires a whitelist");
1277
1278        if (base_path && !is_directory(base_path))
1279                die("base-path '%s' does not exist or is not a directory",
1280                    base_path);
1281
1282        if (inetd_mode) {
1283                if (!freopen("/dev/null", "w", stderr))
1284                        die_errno("failed to redirect stderr to /dev/null");
1285        }
1286
1287        if (inetd_mode || serve_mode)
1288                return execute();
1289
1290        if (detach) {
1291                if (daemonize())
1292                        die("--detach not supported on this platform");
1293        } else
1294                sanitize_stdfds();
1295
1296        if (pid_file)
1297                store_pid(pid_file);
1298
1299        /* prepare argv for serving-processes */
1300        cld_argv = xmalloc(sizeof (char *) * (argc + 2));
1301        cld_argv[0] = argv[0];  /* git-daemon */
1302        cld_argv[1] = "--serve";
1303        for (i = 1; i < argc; ++i)
1304                cld_argv[i+1] = argv[i];
1305        cld_argv[argc+1] = NULL;
1306
1307        return serve(&listen_addr, listen_port, cred);
1308}