Andrew's git / gitweb.git / daemon.c
?
daemon.con commit Merge branch 'rs/daemon-interpolate' (ef4cdb8)
   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 int hostname_lookup_done;
  65
  66static void lookup_hostname(void);
  67
  68static const char *get_canon_hostname(void)
  69{
  70        lookup_hostname();
  71        return canon_hostname;
  72}
  73
  74static const char *get_ip_address(void)
  75{
  76        lookup_hostname();
  77        return ip_address;
  78}
  79
  80static void logreport(int priority, const char *err, va_list params)
  81{
  82        if (log_syslog) {
  83                char buf[1024];
  84                vsnprintf(buf, sizeof(buf), err, params);
  85                syslog(priority, "%s", buf);
  86        } else {
  87                /*
  88                 * Since stderr is set to buffered mode, the
  89                 * logging of different processes will not overlap
  90                 * unless they overflow the (rather big) buffers.
  91                 */
  92                fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
  93                vfprintf(stderr, err, params);
  94                fputc('\n', stderr);
  95                fflush(stderr);
  96        }
  97}
  98
  99__attribute__((format (printf, 1, 2)))
 100static void logerror(const char *err, ...)
 101{
 102        va_list params;
 103        va_start(params, err);
 104        logreport(LOG_ERR, err, params);
 105        va_end(params);
 106}
 107
 108__attribute__((format (printf, 1, 2)))
 109static void loginfo(const char *err, ...)
 110{
 111        va_list params;
 112        if (!verbose)
 113                return;
 114        va_start(params, err);
 115        logreport(LOG_INFO, err, params);
 116        va_end(params);
 117}
 118
 119static void NORETURN daemon_die(const char *err, va_list params)
 120{
 121        logreport(LOG_ERR, err, params);
 122        exit(1);
 123}
 124
 125static void strbuf_addstr_or_null(struct strbuf *sb, const char *s)
 126{
 127        if (s)
 128                strbuf_addstr(sb, s);
 129}
 130
 131struct expand_path_context {
 132        const char *directory;
 133};
 134
 135static size_t expand_path(struct strbuf *sb, const char *placeholder, void *ctx)
 136{
 137        struct expand_path_context *context = ctx;
 138
 139        switch (placeholder[0]) {
 140        case 'H':
 141                strbuf_addstr_or_null(sb, hostname);
 142                return 1;
 143        case 'C':
 144                if (placeholder[1] == 'H') {
 145                        strbuf_addstr_or_null(sb, get_canon_hostname());
 146                        return 2;
 147                }
 148                break;
 149        case 'I':
 150                if (placeholder[1] == 'P') {
 151                        strbuf_addstr_or_null(sb, get_ip_address());
 152                        return 2;
 153                }
 154                break;
 155        case 'P':
 156                strbuf_addstr_or_null(sb, tcp_port);
 157                return 1;
 158        case 'D':
 159                strbuf_addstr(sb, context->directory);
 160                return 1;
 161        }
 162        return 0;
 163}
 164
 165static const char *path_ok(const char *directory)
 166{
 167        static char rpath[PATH_MAX];
 168        static char interp_path[PATH_MAX];
 169        const char *path;
 170        const char *dir;
 171
 172        dir = directory;
 173
 174        if (daemon_avoid_alias(dir)) {
 175                logerror("'%s': aliased", dir);
 176                return NULL;
 177        }
 178
 179        if (*dir == '~') {
 180                if (!user_path) {
 181                        logerror("'%s': User-path not allowed", dir);
 182                        return NULL;
 183                }
 184                if (*user_path) {
 185                        /* Got either "~alice" or "~alice/foo";
 186                         * rewrite them to "~alice/%s" or
 187                         * "~alice/%s/foo".
 188                         */
 189                        int namlen, restlen = strlen(dir);
 190                        const char *slash = strchr(dir, '/');
 191                        if (!slash)
 192                                slash = dir + restlen;
 193                        namlen = slash - dir;
 194                        restlen -= namlen;
 195                        loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
 196                        snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
 197                                 namlen, dir, user_path, restlen, slash);
 198                        dir = rpath;
 199                }
 200        }
 201        else if (interpolated_path && saw_extended_args) {
 202                struct strbuf expanded_path = STRBUF_INIT;
 203                struct expand_path_context context;
 204
 205                context.directory = directory;
 206
 207                if (*dir != '/') {
 208                        /* Allow only absolute */
 209                        logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
 210                        return NULL;
 211                }
 212
 213                strbuf_expand(&expanded_path, interpolated_path,
 214                              expand_path, &context);
 215                strlcpy(interp_path, expanded_path.buf, PATH_MAX);
 216                strbuf_release(&expanded_path);
 217                loginfo("Interpolated dir '%s'", interp_path);
 218
 219                dir = interp_path;
 220        }
 221        else if (base_path) {
 222                if (*dir != '/') {
 223                        /* Allow only absolute */
 224                        logerror("'%s': Non-absolute path denied (base-path active)", dir);
 225                        return NULL;
 226                }
 227                snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
 228                dir = rpath;
 229        }
 230
 231        path = enter_repo(dir, strict_paths);
 232        if (!path && base_path && base_path_relaxed) {
 233                /*
 234                 * if we fail and base_path_relaxed is enabled, try without
 235                 * prefixing the base path
 236                 */
 237                dir = directory;
 238                path = enter_repo(dir, strict_paths);
 239        }
 240
 241        if (!path) {
 242                logerror("'%s' does not appear to be a git repository", dir);
 243                return NULL;
 244        }
 245
 246        if ( ok_paths && *ok_paths ) {
 247                char **pp;
 248                int pathlen = strlen(path);
 249
 250                /* The validation is done on the paths after enter_repo
 251                 * appends optional {.git,.git/.git} and friends, but
 252                 * it does not use getcwd().  So if your /pub is
 253                 * a symlink to /mnt/pub, you can whitelist /pub and
 254                 * do not have to say /mnt/pub.
 255                 * Do not say /pub/.
 256                 */
 257                for ( pp = ok_paths ; *pp ; pp++ ) {
 258                        int len = strlen(*pp);
 259                        if (len <= pathlen &&
 260                            !memcmp(*pp, path, len) &&
 261                            (path[len] == '\0' ||
 262                             (!strict_paths && path[len] == '/')))
 263                                return path;
 264                }
 265        }
 266        else {
 267                /* be backwards compatible */
 268                if (!strict_paths)
 269                        return path;
 270        }
 271
 272        logerror("'%s': not in whitelist", path);
 273        return NULL;            /* Fallthrough. Deny by default */
 274}
 275
 276typedef int (*daemon_service_fn)(void);
 277struct daemon_service {
 278        const char *name;
 279        const char *config_name;
 280        daemon_service_fn fn;
 281        int enabled;
 282        int overridable;
 283};
 284
 285static int daemon_error(const char *dir, const char *msg)
 286{
 287        if (!informative_errors)
 288                msg = "access denied or repository not exported";
 289        packet_write(1, "ERR %s: %s", msg, dir);
 290        return -1;
 291}
 292
 293static const char *access_hook;
 294
 295static int run_access_hook(struct daemon_service *service, const char *dir, const char *path)
 296{
 297        struct child_process child = CHILD_PROCESS_INIT;
 298        struct strbuf buf = STRBUF_INIT;
 299        const char *argv[8];
 300        const char **arg = argv;
 301        char *eol;
 302        int seen_errors = 0;
 303
 304#define STRARG(x) ((x) ? (x) : "")
 305        *arg++ = access_hook;
 306        *arg++ = service->name;
 307        *arg++ = path;
 308        *arg++ = STRARG(hostname);
 309        *arg++ = STRARG(get_canon_hostname());
 310        *arg++ = STRARG(get_ip_address());
 311        *arg++ = STRARG(tcp_port);
 312        *arg = NULL;
 313#undef STRARG
 314
 315        child.use_shell = 1;
 316        child.argv = argv;
 317        child.no_stdin = 1;
 318        child.no_stderr = 1;
 319        child.out = -1;
 320        if (start_command(&child)) {
 321                logerror("daemon access hook '%s' failed to start",
 322                         access_hook);
 323                goto error_return;
 324        }
 325        if (strbuf_read(&buf, child.out, 0) < 0) {
 326                logerror("failed to read from pipe to daemon access hook '%s'",
 327                         access_hook);
 328                strbuf_reset(&buf);
 329                seen_errors = 1;
 330        }
 331        if (close(child.out) < 0) {
 332                logerror("failed to close pipe to daemon access hook '%s'",
 333                         access_hook);
 334                seen_errors = 1;
 335        }
 336        if (finish_command(&child))
 337                seen_errors = 1;
 338
 339        if (!seen_errors) {
 340                strbuf_release(&buf);
 341                return 0;
 342        }
 343
 344error_return:
 345        strbuf_ltrim(&buf);
 346        if (!buf.len)
 347                strbuf_addstr(&buf, "service rejected");
 348        eol = strchr(buf.buf, '\n');
 349        if (eol)
 350                *eol = '\0';
 351        errno = EACCES;
 352        daemon_error(dir, buf.buf);
 353        strbuf_release(&buf);
 354        return -1;
 355}
 356
 357static int run_service(const char *dir, struct daemon_service *service)
 358{
 359        const char *path;
 360        int enabled = service->enabled;
 361        struct strbuf var = STRBUF_INIT;
 362
 363        loginfo("Request %s for '%s'", service->name, dir);
 364
 365        if (!enabled && !service->overridable) {
 366                logerror("'%s': service not enabled.", service->name);
 367                errno = EACCES;
 368                return daemon_error(dir, "service not enabled");
 369        }
 370
 371        if (!(path = path_ok(dir)))
 372                return daemon_error(dir, "no such repository");
 373
 374        /*
 375         * Security on the cheap.
 376         *
 377         * We want a readable HEAD, usable "objects" directory, and
 378         * a "git-daemon-export-ok" flag that says that the other side
 379         * is ok with us doing this.
 380         *
 381         * path_ok() uses enter_repo() and does whitelist checking.
 382         * We only need to make sure the repository is exported.
 383         */
 384
 385        if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 386                logerror("'%s': repository not exported.", path);
 387                errno = EACCES;
 388                return daemon_error(dir, "repository not exported");
 389        }
 390
 391        if (service->overridable) {
 392                strbuf_addf(&var, "daemon.%s", service->config_name);
 393                git_config_get_bool(var.buf, &enabled);
 394                strbuf_release(&var);
 395        }
 396        if (!enabled) {
 397                logerror("'%s': service not enabled for '%s'",
 398                         service->name, path);
 399                errno = EACCES;
 400                return daemon_error(dir, "service not enabled");
 401        }
 402
 403        /*
 404         * Optionally, a hook can choose to deny access to the
 405         * repository depending on the phase of the moon.
 406         */
 407        if (access_hook && run_access_hook(service, dir, path))
 408                return -1;
 409
 410        /*
 411         * We'll ignore SIGTERM from now on, we have a
 412         * good client.
 413         */
 414        signal(SIGTERM, SIG_IGN);
 415
 416        return service->fn();
 417}
 418
 419static void copy_to_log(int fd)
 420{
 421        struct strbuf line = STRBUF_INIT;
 422        FILE *fp;
 423
 424        fp = fdopen(fd, "r");
 425        if (fp == NULL) {
 426                logerror("fdopen of error channel failed");
 427                close(fd);
 428                return;
 429        }
 430
 431        while (strbuf_getline(&line, fp, '\n') != EOF) {
 432                logerror("%s", line.buf);
 433                strbuf_setlen(&line, 0);
 434        }
 435
 436        strbuf_release(&line);
 437        fclose(fp);
 438}
 439
 440static int run_service_command(const char **argv)
 441{
 442        struct child_process cld = CHILD_PROCESS_INIT;
 443
 444        cld.argv = argv;
 445        cld.git_cmd = 1;
 446        cld.err = -1;
 447        if (start_command(&cld))
 448                return -1;
 449
 450        close(0);
 451        close(1);
 452
 453        copy_to_log(cld.err);
 454
 455        return finish_command(&cld);
 456}
 457
 458static int upload_pack(void)
 459{
 460        /* Timeout as string */
 461        char timeout_buf[64];
 462        const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
 463
 464        argv[2] = timeout_buf;
 465
 466        snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 467        return run_service_command(argv);
 468}
 469
 470static int upload_archive(void)
 471{
 472        static const char *argv[] = { "upload-archive", ".", NULL };
 473        return run_service_command(argv);
 474}
 475
 476static int receive_pack(void)
 477{
 478        static const char *argv[] = { "receive-pack", ".", NULL };
 479        return run_service_command(argv);
 480}
 481
 482static struct daemon_service daemon_service[] = {
 483        { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 484        { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 485        { "receive-pack", "receivepack", receive_pack, 0, 1 },
 486};
 487
 488static void enable_service(const char *name, int ena)
 489{
 490        int i;
 491        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 492                if (!strcmp(daemon_service[i].name, name)) {
 493                        daemon_service[i].enabled = ena;
 494                        return;
 495                }
 496        }
 497        die("No such service %s", name);
 498}
 499
 500static void make_service_overridable(const char *name, int ena)
 501{
 502        int i;
 503        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 504                if (!strcmp(daemon_service[i].name, name)) {
 505                        daemon_service[i].overridable = ena;
 506                        return;
 507                }
 508        }
 509        die("No such service %s", name);
 510}
 511
 512static void parse_host_and_port(char *hostport, char **host,
 513        char **port)
 514{
 515        if (*hostport == '[') {
 516                char *end;
 517
 518                end = strchr(hostport, ']');
 519                if (!end)
 520                        die("Invalid request ('[' without ']')");
 521                *end = '\0';
 522                *host = hostport + 1;
 523                if (!end[1])
 524                        *port = NULL;
 525                else if (end[1] == ':')
 526                        *port = end + 2;
 527                else
 528                        die("Garbage after end of host part");
 529        } else {
 530                *host = hostport;
 531                *port = strrchr(hostport, ':');
 532                if (*port) {
 533                        **port = '\0';
 534                        ++*port;
 535                }
 536        }
 537}
 538
 539/*
 540 * Read the host as supplied by the client connection.
 541 */
 542static void parse_host_arg(char *extra_args, int buflen)
 543{
 544        char *val;
 545        int vallen;
 546        char *end = extra_args + buflen;
 547
 548        if (extra_args < end && *extra_args) {
 549                saw_extended_args = 1;
 550                if (strncasecmp("host=", extra_args, 5) == 0) {
 551                        val = extra_args + 5;
 552                        vallen = strlen(val) + 1;
 553                        if (*val) {
 554                                /* Split <host>:<port> at colon. */
 555                                char *host;
 556                                char *port;
 557                                parse_host_and_port(val, &host, &port);
 558                                if (port) {
 559                                        free(tcp_port);
 560                                        tcp_port = xstrdup(port);
 561                                }
 562                                free(hostname);
 563                                hostname = xstrdup_tolower(host);
 564                                hostname_lookup_done = 0;
 565                        }
 566
 567                        /* On to the next one */
 568                        extra_args = val + vallen;
 569                }
 570                if (extra_args < end && *extra_args)
 571                        die("Invalid request");
 572        }
 573}
 574
 575/*
 576 * Locate canonical hostname and its IP address.
 577 */
 578static void lookup_hostname(void)
 579{
 580        if (!hostname_lookup_done && hostname) {
 581#ifndef NO_IPV6
 582                struct addrinfo hints;
 583                struct addrinfo *ai;
 584                int gai;
 585                static char addrbuf[HOST_NAME_MAX + 1];
 586
 587                memset(&hints, 0, sizeof(hints));
 588                hints.ai_flags = AI_CANONNAME;
 589
 590                gai = getaddrinfo(hostname, NULL, &hints, &ai);
 591                if (!gai) {
 592                        struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 593
 594                        inet_ntop(AF_INET, &sin_addr->sin_addr,
 595                                  addrbuf, sizeof(addrbuf));
 596                        free(ip_address);
 597                        ip_address = xstrdup(addrbuf);
 598
 599                        free(canon_hostname);
 600                        canon_hostname = xstrdup(ai->ai_canonname ?
 601                                                 ai->ai_canonname : ip_address);
 602
 603                        freeaddrinfo(ai);
 604                }
 605#else
 606                struct hostent *hent;
 607                struct sockaddr_in sa;
 608                char **ap;
 609                static char addrbuf[HOST_NAME_MAX + 1];
 610
 611                hent = gethostbyname(hostname);
 612                if (hent) {
 613                        ap = hent->h_addr_list;
 614                        memset(&sa, 0, sizeof sa);
 615                        sa.sin_family = hent->h_addrtype;
 616                        sa.sin_port = htons(0);
 617                        memcpy(&sa.sin_addr, *ap, hent->h_length);
 618
 619                        inet_ntop(hent->h_addrtype, &sa.sin_addr,
 620                                  addrbuf, sizeof(addrbuf));
 621
 622                        free(canon_hostname);
 623                        canon_hostname = xstrdup(hent->h_name);
 624                        free(ip_address);
 625                        ip_address = xstrdup(addrbuf);
 626                }
 627#endif
 628                hostname_lookup_done = 1;
 629        }
 630}
 631
 632
 633static int execute(void)
 634{
 635        char *line = packet_buffer;
 636        int pktlen, len, i;
 637        char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
 638
 639        if (addr)
 640                loginfo("Connection from %s:%s", addr, port);
 641
 642        alarm(init_timeout ? init_timeout : timeout);
 643        pktlen = packet_read(0, NULL, NULL, packet_buffer, sizeof(packet_buffer), 0);
 644        alarm(0);
 645
 646        len = strlen(line);
 647        if (pktlen != len)
 648                loginfo("Extended attributes (%d bytes) exist <%.*s>",
 649                        (int) pktlen - len,
 650                        (int) pktlen - len, line + len + 1);
 651        if (len && line[len-1] == '\n') {
 652                line[--len] = 0;
 653                pktlen--;
 654        }
 655
 656        free(hostname);
 657        free(canon_hostname);
 658        free(ip_address);
 659        free(tcp_port);
 660        hostname = canon_hostname = ip_address = tcp_port = NULL;
 661
 662        if (len != pktlen)
 663                parse_host_arg(line + len + 1, pktlen - len - 1);
 664
 665        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 666                struct daemon_service *s = &(daemon_service[i]);
 667                const char *arg;
 668
 669                if (skip_prefix(line, "git-", &arg) &&
 670                    skip_prefix(arg, s->name, &arg) &&
 671                    *arg++ == ' ') {
 672                        /*
 673                         * Note: The directory here is probably context sensitive,
 674                         * and might depend on the actual service being performed.
 675                         */
 676                        return run_service(arg, s);
 677                }
 678        }
 679
 680        logerror("Protocol error: '%s'", line);
 681        return -1;
 682}
 683
 684static int addrcmp(const struct sockaddr_storage *s1,
 685    const struct sockaddr_storage *s2)
 686{
 687        const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 688        const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 689
 690        if (sa1->sa_family != sa2->sa_family)
 691                return sa1->sa_family - sa2->sa_family;
 692        if (sa1->sa_family == AF_INET)
 693                return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 694                    &((struct sockaddr_in *)s2)->sin_addr,
 695                    sizeof(struct in_addr));
 696#ifndef NO_IPV6
 697        if (sa1->sa_family == AF_INET6)
 698                return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 699                    &((struct sockaddr_in6 *)s2)->sin6_addr,
 700                    sizeof(struct in6_addr));
 701#endif
 702        return 0;
 703}
 704
 705static int max_connections = 32;
 706
 707static unsigned int live_children;
 708
 709static struct child {
 710        struct child *next;
 711        struct child_process cld;
 712        struct sockaddr_storage address;
 713} *firstborn;
 714
 715static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
 716{
 717        struct child *newborn, **cradle;
 718
 719        newborn = xcalloc(1, sizeof(*newborn));
 720        live_children++;
 721        memcpy(&newborn->cld, cld, sizeof(*cld));
 722        memcpy(&newborn->address, addr, addrlen);
 723        for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 724                if (!addrcmp(&(*cradle)->address, &newborn->address))
 725                        break;
 726        newborn->next = *cradle;
 727        *cradle = newborn;
 728}
 729
 730/*
 731 * This gets called if the number of connections grows
 732 * past "max_connections".
 733 *
 734 * We kill the newest connection from a duplicate IP.
 735 */
 736static void kill_some_child(void)
 737{
 738        const struct child *blanket, *next;
 739
 740        if (!(blanket = firstborn))
 741                return;
 742
 743        for (; (next = blanket->next); blanket = next)
 744                if (!addrcmp(&blanket->address, &next->address)) {
 745                        kill(blanket->cld.pid, SIGTERM);
 746                        break;
 747                }
 748}
 749
 750static void check_dead_children(void)
 751{
 752        int status;
 753        pid_t pid;
 754
 755        struct child **cradle, *blanket;
 756        for (cradle = &firstborn; (blanket = *cradle);)
 757                if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
 758                        const char *dead = "";
 759                        if (status)
 760                                dead = " (with error)";
 761                        loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 762
 763                        /* remove the child */
 764                        *cradle = blanket->next;
 765                        live_children--;
 766                        free(blanket);
 767                } else
 768                        cradle = &blanket->next;
 769}
 770
 771static char **cld_argv;
 772static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 773{
 774        struct child_process cld = CHILD_PROCESS_INIT;
 775        char addrbuf[300] = "REMOTE_ADDR=", portbuf[300];
 776        char *env[] = { addrbuf, portbuf, NULL };
 777
 778        if (max_connections && live_children >= max_connections) {
 779                kill_some_child();
 780                sleep(1);  /* give it some time to die */
 781                check_dead_children();
 782                if (live_children >= max_connections) {
 783                        close(incoming);
 784                        logerror("Too many children, dropping connection");
 785                        return;
 786                }
 787        }
 788
 789        if (addr->sa_family == AF_INET) {
 790                struct sockaddr_in *sin_addr = (void *) addr;
 791                inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf + 12,
 792                    sizeof(addrbuf) - 12);
 793                snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 794                    ntohs(sin_addr->sin_port));
 795#ifndef NO_IPV6
 796        } else if (addr->sa_family == AF_INET6) {
 797                struct sockaddr_in6 *sin6_addr = (void *) addr;
 798
 799                char *buf = addrbuf + 12;
 800                *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 801                inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf,
 802                    sizeof(addrbuf) - 13);
 803                strcat(buf, "]");
 804
 805                snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 806                    ntohs(sin6_addr->sin6_port));
 807#endif
 808        }
 809
 810        cld.env = (const char **)env;
 811        cld.argv = (const char **)cld_argv;
 812        cld.in = incoming;
 813        cld.out = dup(incoming);
 814
 815        if (start_command(&cld))
 816                logerror("unable to fork");
 817        else
 818                add_child(&cld, addr, addrlen);
 819}
 820
 821static void child_handler(int signo)
 822{
 823        /*
 824         * Otherwise empty handler because systemcalls will get interrupted
 825         * upon signal receipt
 826         * SysV needs the handler to be rearmed
 827         */
 828        signal(SIGCHLD, child_handler);
 829}
 830
 831static int set_reuse_addr(int sockfd)
 832{
 833        int on = 1;
 834
 835        if (!reuseaddr)
 836                return 0;
 837        return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 838                          &on, sizeof(on));
 839}
 840
 841struct socketlist {
 842        int *list;
 843        size_t nr;
 844        size_t alloc;
 845};
 846
 847static const char *ip2str(int family, struct sockaddr *sin, socklen_t len)
 848{
 849#ifdef NO_IPV6
 850        static char ip[INET_ADDRSTRLEN];
 851#else
 852        static char ip[INET6_ADDRSTRLEN];
 853#endif
 854
 855        switch (family) {
 856#ifndef NO_IPV6
 857        case AF_INET6:
 858                inet_ntop(family, &((struct sockaddr_in6*)sin)->sin6_addr, ip, len);
 859                break;
 860#endif
 861        case AF_INET:
 862                inet_ntop(family, &((struct sockaddr_in*)sin)->sin_addr, ip, len);
 863                break;
 864        default:
 865                strcpy(ip, "<unknown>");
 866        }
 867        return ip;
 868}
 869
 870#ifndef NO_IPV6
 871
 872static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 873{
 874        int socknum = 0;
 875        char pbuf[NI_MAXSERV];
 876        struct addrinfo hints, *ai0, *ai;
 877        int gai;
 878        long flags;
 879
 880        sprintf(pbuf, "%d", listen_port);
 881        memset(&hints, 0, sizeof(hints));
 882        hints.ai_family = AF_UNSPEC;
 883        hints.ai_socktype = SOCK_STREAM;
 884        hints.ai_protocol = IPPROTO_TCP;
 885        hints.ai_flags = AI_PASSIVE;
 886
 887        gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 888        if (gai) {
 889                logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
 890                return 0;
 891        }
 892
 893        for (ai = ai0; ai; ai = ai->ai_next) {
 894                int sockfd;
 895
 896                sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 897                if (sockfd < 0)
 898                        continue;
 899                if (sockfd >= FD_SETSIZE) {
 900                        logerror("Socket descriptor too large");
 901                        close(sockfd);
 902                        continue;
 903                }
 904
 905#ifdef IPV6_V6ONLY
 906                if (ai->ai_family == AF_INET6) {
 907                        int on = 1;
 908                        setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 909                                   &on, sizeof(on));
 910                        /* Note: error is not fatal */
 911                }
 912#endif
 913
 914                if (set_reuse_addr(sockfd)) {
 915                        logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 916                        close(sockfd);
 917                        continue;
 918                }
 919
 920                if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 921                        logerror("Could not bind to %s: %s",
 922                                 ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 923                                 strerror(errno));
 924                        close(sockfd);
 925                        continue;       /* not fatal */
 926                }
 927                if (listen(sockfd, 5) < 0) {
 928                        logerror("Could not listen to %s: %s",
 929                                 ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 930                                 strerror(errno));
 931                        close(sockfd);
 932                        continue;       /* not fatal */
 933                }
 934
 935                flags = fcntl(sockfd, F_GETFD, 0);
 936                if (flags >= 0)
 937                        fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 938
 939                ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 940                socklist->list[socklist->nr++] = sockfd;
 941                socknum++;
 942        }
 943
 944        freeaddrinfo(ai0);
 945
 946        return socknum;
 947}
 948
 949#else /* NO_IPV6 */
 950
 951static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 952{
 953        struct sockaddr_in sin;
 954        int sockfd;
 955        long flags;
 956
 957        memset(&sin, 0, sizeof sin);
 958        sin.sin_family = AF_INET;
 959        sin.sin_port = htons(listen_port);
 960
 961        if (listen_addr) {
 962                /* Well, host better be an IP address here. */
 963                if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 964                        return 0;
 965        } else {
 966                sin.sin_addr.s_addr = htonl(INADDR_ANY);
 967        }
 968
 969        sockfd = socket(AF_INET, SOCK_STREAM, 0);
 970        if (sockfd < 0)
 971                return 0;
 972
 973        if (set_reuse_addr(sockfd)) {
 974                logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 975                close(sockfd);
 976                return 0;
 977        }
 978
 979        if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 980                logerror("Could not bind to %s: %s",
 981                         ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
 982                         strerror(errno));
 983                close(sockfd);
 984                return 0;
 985        }
 986
 987        if (listen(sockfd, 5) < 0) {
 988                logerror("Could not listen to %s: %s",
 989                         ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
 990                         strerror(errno));
 991                close(sockfd);
 992                return 0;
 993        }
 994
 995        flags = fcntl(sockfd, F_GETFD, 0);
 996        if (flags >= 0)
 997                fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 998
 999        ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
1000        socklist->list[socklist->nr++] = sockfd;
1001        return 1;
1002}
1003
1004#endif
1005
1006static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
1007{
1008        if (!listen_addr->nr)
1009                setup_named_sock(NULL, listen_port, socklist);
1010        else {
1011                int i, socknum;
1012                for (i = 0; i < listen_addr->nr; i++) {
1013                        socknum = setup_named_sock(listen_addr->items[i].string,
1014                                                   listen_port, socklist);
1015
1016                        if (socknum == 0)
1017                                logerror("unable to allocate any listen sockets for host %s on port %u",
1018                                         listen_addr->items[i].string, listen_port);
1019                }
1020        }
1021}
1022
1023static int service_loop(struct socketlist *socklist)
1024{
1025        struct pollfd *pfd;
1026        int i;
1027
1028        pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
1029
1030        for (i = 0; i < socklist->nr; i++) {
1031                pfd[i].fd = socklist->list[i];
1032                pfd[i].events = POLLIN;
1033        }
1034
1035        signal(SIGCHLD, child_handler);
1036
1037        for (;;) {
1038                int i;
1039
1040                check_dead_children();
1041
1042                if (poll(pfd, socklist->nr, -1) < 0) {
1043                        if (errno != EINTR) {
1044                                logerror("Poll failed, resuming: %s",
1045                                      strerror(errno));
1046                                sleep(1);
1047                        }
1048                        continue;
1049                }
1050
1051                for (i = 0; i < socklist->nr; i++) {
1052                        if (pfd[i].revents & POLLIN) {
1053                                union {
1054                                        struct sockaddr sa;
1055                                        struct sockaddr_in sai;
1056#ifndef NO_IPV6
1057                                        struct sockaddr_in6 sai6;
1058#endif
1059                                } ss;
1060                                socklen_t sslen = sizeof(ss);
1061                                int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
1062                                if (incoming < 0) {
1063                                        switch (errno) {
1064                                        case EAGAIN:
1065                                        case EINTR:
1066                                        case ECONNABORTED:
1067                                                continue;
1068                                        default:
1069                                                die_errno("accept returned");
1070                                        }
1071                                }
1072                                handle(incoming, &ss.sa, sslen);
1073                        }
1074                }
1075        }
1076}
1077
1078#ifdef NO_POSIX_GOODIES
1079
1080struct credentials;
1081
1082static void drop_privileges(struct credentials *cred)
1083{
1084        /* nothing */
1085}
1086
1087static struct credentials *prepare_credentials(const char *user_name,
1088    const char *group_name)
1089{
1090        die("--user not supported on this platform");
1091}
1092
1093#else
1094
1095struct credentials {
1096        struct passwd *pass;
1097        gid_t gid;
1098};
1099
1100static void drop_privileges(struct credentials *cred)
1101{
1102        if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
1103            setgid (cred->gid) || setuid(cred->pass->pw_uid)))
1104                die("cannot drop privileges");
1105}
1106
1107static struct credentials *prepare_credentials(const char *user_name,
1108    const char *group_name)
1109{
1110        static struct credentials c;
1111
1112        c.pass = getpwnam(user_name);
1113        if (!c.pass)
1114                die("user not found - %s", user_name);
1115
1116        if (!group_name)
1117                c.gid = c.pass->pw_gid;
1118        else {
1119                struct group *group = getgrnam(group_name);
1120                if (!group)
1121                        die("group not found - %s", group_name);
1122
1123                c.gid = group->gr_gid;
1124        }
1125
1126        return &c;
1127}
1128#endif
1129
1130static void store_pid(const char *path)
1131{
1132        FILE *f = fopen(path, "w");
1133        if (!f)
1134                die_errno("cannot open pid file '%s'", path);
1135        if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
1136                die_errno("failed to write pid file '%s'", path);
1137}
1138
1139static int serve(struct string_list *listen_addr, int listen_port,
1140    struct credentials *cred)
1141{
1142        struct socketlist socklist = { NULL, 0, 0 };
1143
1144        socksetup(listen_addr, listen_port, &socklist);
1145        if (socklist.nr == 0)
1146                die("unable to allocate any listen sockets on port %u",
1147                    listen_port);
1148
1149        drop_privileges(cred);
1150
1151        loginfo("Ready to rumble");
1152
1153        return service_loop(&socklist);
1154}
1155
1156int main(int argc, char **argv)
1157{
1158        int listen_port = 0;
1159        struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1160        int serve_mode = 0, inetd_mode = 0;
1161        const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1162        int detach = 0;
1163        struct credentials *cred = NULL;
1164        int i;
1165
1166        git_setup_gettext();
1167
1168        git_extract_argv0_path(argv[0]);
1169
1170        for (i = 1; i < argc; i++) {
1171                char *arg = argv[i];
1172                const char *v;
1173
1174                if (skip_prefix(arg, "--listen=", &v)) {
1175                        string_list_append(&listen_addr, xstrdup_tolower(v));
1176                        continue;
1177                }
1178                if (skip_prefix(arg, "--port=", &v)) {
1179                        char *end;
1180                        unsigned long n;
1181                        n = strtoul(v, &end, 0);
1182                        if (*v && !*end) {
1183                                listen_port = n;
1184                                continue;
1185                        }
1186                }
1187                if (!strcmp(arg, "--serve")) {
1188                        serve_mode = 1;
1189                        continue;
1190                }
1191                if (!strcmp(arg, "--inetd")) {
1192                        inetd_mode = 1;
1193                        log_syslog = 1;
1194                        continue;
1195                }
1196                if (!strcmp(arg, "--verbose")) {
1197                        verbose = 1;
1198                        continue;
1199                }
1200                if (!strcmp(arg, "--syslog")) {
1201                        log_syslog = 1;
1202                        continue;
1203                }
1204                if (!strcmp(arg, "--export-all")) {
1205                        export_all_trees = 1;
1206                        continue;
1207                }
1208                if (skip_prefix(arg, "--access-hook=", &v)) {
1209                        access_hook = v;
1210                        continue;
1211                }
1212                if (skip_prefix(arg, "--timeout=", &v)) {
1213                        timeout = atoi(v);
1214                        continue;
1215                }
1216                if (skip_prefix(arg, "--init-timeout=", &v)) {
1217                        init_timeout = atoi(v);
1218                        continue;
1219                }
1220                if (skip_prefix(arg, "--max-connections=", &v)) {
1221                        max_connections = atoi(v);
1222                        if (max_connections < 0)
1223                                max_connections = 0;            /* unlimited */
1224                        continue;
1225                }
1226                if (!strcmp(arg, "--strict-paths")) {
1227                        strict_paths = 1;
1228                        continue;
1229                }
1230                if (skip_prefix(arg, "--base-path=", &v)) {
1231                        base_path = v;
1232                        continue;
1233                }
1234                if (!strcmp(arg, "--base-path-relaxed")) {
1235                        base_path_relaxed = 1;
1236                        continue;
1237                }
1238                if (skip_prefix(arg, "--interpolated-path=", &v)) {
1239                        interpolated_path = v;
1240                        continue;
1241                }
1242                if (!strcmp(arg, "--reuseaddr")) {
1243                        reuseaddr = 1;
1244                        continue;
1245                }
1246                if (!strcmp(arg, "--user-path")) {
1247                        user_path = "";
1248                        continue;
1249                }
1250                if (skip_prefix(arg, "--user-path=", &v)) {
1251                        user_path = v;
1252                        continue;
1253                }
1254                if (skip_prefix(arg, "--pid-file=", &v)) {
1255                        pid_file = v;
1256                        continue;
1257                }
1258                if (!strcmp(arg, "--detach")) {
1259                        detach = 1;
1260                        log_syslog = 1;
1261                        continue;
1262                }
1263                if (skip_prefix(arg, "--user=", &v)) {
1264                        user_name = v;
1265                        continue;
1266                }
1267                if (skip_prefix(arg, "--group=", &v)) {
1268                        group_name = v;
1269                        continue;
1270                }
1271                if (skip_prefix(arg, "--enable=", &v)) {
1272                        enable_service(v, 1);
1273                        continue;
1274                }
1275                if (skip_prefix(arg, "--disable=", &v)) {
1276                        enable_service(v, 0);
1277                        continue;
1278                }
1279                if (skip_prefix(arg, "--allow-override=", &v)) {
1280                        make_service_overridable(v, 1);
1281                        continue;
1282                }
1283                if (skip_prefix(arg, "--forbid-override=", &v)) {
1284                        make_service_overridable(v, 0);
1285                        continue;
1286                }
1287                if (!strcmp(arg, "--informative-errors")) {
1288                        informative_errors = 1;
1289                        continue;
1290                }
1291                if (!strcmp(arg, "--no-informative-errors")) {
1292                        informative_errors = 0;
1293                        continue;
1294                }
1295                if (!strcmp(arg, "--")) {
1296                        ok_paths = &argv[i+1];
1297                        break;
1298                } else if (arg[0] != '-') {
1299                        ok_paths = &argv[i];
1300                        break;
1301                }
1302
1303                usage(daemon_usage);
1304        }
1305
1306        if (log_syslog) {
1307                openlog("git-daemon", LOG_PID, LOG_DAEMON);
1308                set_die_routine(daemon_die);
1309        } else
1310                /* avoid splitting a message in the middle */
1311                setvbuf(stderr, NULL, _IOFBF, 4096);
1312
1313        if (inetd_mode && (detach || group_name || user_name))
1314                die("--detach, --user and --group are incompatible with --inetd");
1315
1316        if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1317                die("--listen= and --port= are incompatible with --inetd");
1318        else if (listen_port == 0)
1319                listen_port = DEFAULT_GIT_PORT;
1320
1321        if (group_name && !user_name)
1322                die("--group supplied without --user");
1323
1324        if (user_name)
1325                cred = prepare_credentials(user_name, group_name);
1326
1327        if (strict_paths && (!ok_paths || !*ok_paths))
1328                die("option --strict-paths requires a whitelist");
1329
1330        if (base_path && !is_directory(base_path))
1331                die("base-path '%s' does not exist or is not a directory",
1332                    base_path);
1333
1334        if (inetd_mode) {
1335                if (!freopen("/dev/null", "w", stderr))
1336                        die_errno("failed to redirect stderr to /dev/null");
1337        }
1338
1339        if (inetd_mode || serve_mode)
1340                return execute();
1341
1342        if (detach) {
1343                if (daemonize())
1344                        die("--detach not supported on this platform");
1345        } else
1346                sanitize_stdfds();
1347
1348        if (pid_file)
1349                store_pid(pid_file);
1350
1351        /* prepare argv for serving-processes */
1352        cld_argv = xmalloc(sizeof (char *) * (argc + 2));
1353        cld_argv[0] = argv[0];  /* git-daemon */
1354        cld_argv[1] = "--serve";
1355        for (i = 1; i < argc; ++i)
1356                cld_argv[i+1] = argv[i];
1357        cld_argv[argc+1] = NULL;
1358
1359        return serve(&listen_addr, listen_port, cred);
1360}