Andrew's git / gitweb.git / daemon.c
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daemon.con commit t9801: check git-p4's branch detection with client spec enabled (591707a)
   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 = CHILD_PROCESS_INIT;
 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        child.use_shell = 1;
 264        child.argv = argv;
 265        child.no_stdin = 1;
 266        child.no_stderr = 1;
 267        child.out = -1;
 268        if (start_command(&child)) {
 269                logerror("daemon access hook '%s' failed to start",
 270                         access_hook);
 271                goto error_return;
 272        }
 273        if (strbuf_read(&buf, child.out, 0) < 0) {
 274                logerror("failed to read from pipe to daemon access hook '%s'",
 275                         access_hook);
 276                strbuf_reset(&buf);
 277                seen_errors = 1;
 278        }
 279        if (close(child.out) < 0) {
 280                logerror("failed to close pipe to daemon access hook '%s'",
 281                         access_hook);
 282                seen_errors = 1;
 283        }
 284        if (finish_command(&child))
 285                seen_errors = 1;
 286
 287        if (!seen_errors) {
 288                strbuf_release(&buf);
 289                return 0;
 290        }
 291
 292error_return:
 293        strbuf_ltrim(&buf);
 294        if (!buf.len)
 295                strbuf_addstr(&buf, "service rejected");
 296        eol = strchr(buf.buf, '\n');
 297        if (eol)
 298                *eol = '\0';
 299        errno = EACCES;
 300        daemon_error(dir, buf.buf);
 301        strbuf_release(&buf);
 302        return -1;
 303}
 304
 305static int run_service(const char *dir, struct daemon_service *service)
 306{
 307        const char *path;
 308        int enabled = service->enabled;
 309        struct strbuf var = STRBUF_INIT;
 310
 311        loginfo("Request %s for '%s'", service->name, dir);
 312
 313        if (!enabled && !service->overridable) {
 314                logerror("'%s': service not enabled.", service->name);
 315                errno = EACCES;
 316                return daemon_error(dir, "service not enabled");
 317        }
 318
 319        if (!(path = path_ok(dir)))
 320                return daemon_error(dir, "no such repository");
 321
 322        /*
 323         * Security on the cheap.
 324         *
 325         * We want a readable HEAD, usable "objects" directory, and
 326         * a "git-daemon-export-ok" flag that says that the other side
 327         * is ok with us doing this.
 328         *
 329         * path_ok() uses enter_repo() and does whitelist checking.
 330         * We only need to make sure the repository is exported.
 331         */
 332
 333        if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
 334                logerror("'%s': repository not exported.", path);
 335                errno = EACCES;
 336                return daemon_error(dir, "repository not exported");
 337        }
 338
 339        if (service->overridable) {
 340                strbuf_addf(&var, "daemon.%s", service->config_name);
 341                git_config_get_bool(var.buf, &enabled);
 342                strbuf_release(&var);
 343        }
 344        if (!enabled) {
 345                logerror("'%s': service not enabled for '%s'",
 346                         service->name, path);
 347                errno = EACCES;
 348                return daemon_error(dir, "service not enabled");
 349        }
 350
 351        /*
 352         * Optionally, a hook can choose to deny access to the
 353         * repository depending on the phase of the moon.
 354         */
 355        if (access_hook && run_access_hook(service, dir, path))
 356                return -1;
 357
 358        /*
 359         * We'll ignore SIGTERM from now on, we have a
 360         * good client.
 361         */
 362        signal(SIGTERM, SIG_IGN);
 363
 364        return service->fn();
 365}
 366
 367static void copy_to_log(int fd)
 368{
 369        struct strbuf line = STRBUF_INIT;
 370        FILE *fp;
 371
 372        fp = fdopen(fd, "r");
 373        if (fp == NULL) {
 374                logerror("fdopen of error channel failed");
 375                close(fd);
 376                return;
 377        }
 378
 379        while (strbuf_getline(&line, fp, '\n') != EOF) {
 380                logerror("%s", line.buf);
 381                strbuf_setlen(&line, 0);
 382        }
 383
 384        strbuf_release(&line);
 385        fclose(fp);
 386}
 387
 388static int run_service_command(const char **argv)
 389{
 390        struct child_process cld = CHILD_PROCESS_INIT;
 391
 392        cld.argv = argv;
 393        cld.git_cmd = 1;
 394        cld.err = -1;
 395        if (start_command(&cld))
 396                return -1;
 397
 398        close(0);
 399        close(1);
 400
 401        copy_to_log(cld.err);
 402
 403        return finish_command(&cld);
 404}
 405
 406static int upload_pack(void)
 407{
 408        /* Timeout as string */
 409        char timeout_buf[64];
 410        const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
 411
 412        argv[2] = timeout_buf;
 413
 414        snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
 415        return run_service_command(argv);
 416}
 417
 418static int upload_archive(void)
 419{
 420        static const char *argv[] = { "upload-archive", ".", NULL };
 421        return run_service_command(argv);
 422}
 423
 424static int receive_pack(void)
 425{
 426        static const char *argv[] = { "receive-pack", ".", NULL };
 427        return run_service_command(argv);
 428}
 429
 430static struct daemon_service daemon_service[] = {
 431        { "upload-archive", "uploadarch", upload_archive, 0, 1 },
 432        { "upload-pack", "uploadpack", upload_pack, 1, 1 },
 433        { "receive-pack", "receivepack", receive_pack, 0, 1 },
 434};
 435
 436static void enable_service(const char *name, int ena)
 437{
 438        int i;
 439        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 440                if (!strcmp(daemon_service[i].name, name)) {
 441                        daemon_service[i].enabled = ena;
 442                        return;
 443                }
 444        }
 445        die("No such service %s", name);
 446}
 447
 448static void make_service_overridable(const char *name, int ena)
 449{
 450        int i;
 451        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 452                if (!strcmp(daemon_service[i].name, name)) {
 453                        daemon_service[i].overridable = ena;
 454                        return;
 455                }
 456        }
 457        die("No such service %s", name);
 458}
 459
 460static void parse_host_and_port(char *hostport, char **host,
 461        char **port)
 462{
 463        if (*hostport == '[') {
 464                char *end;
 465
 466                end = strchr(hostport, ']');
 467                if (!end)
 468                        die("Invalid request ('[' without ']')");
 469                *end = '\0';
 470                *host = hostport + 1;
 471                if (!end[1])
 472                        *port = NULL;
 473                else if (end[1] == ':')
 474                        *port = end + 2;
 475                else
 476                        die("Garbage after end of host part");
 477        } else {
 478                *host = hostport;
 479                *port = strrchr(hostport, ':');
 480                if (*port) {
 481                        **port = '\0';
 482                        ++*port;
 483                }
 484        }
 485}
 486
 487/*
 488 * Read the host as supplied by the client connection.
 489 */
 490static void parse_host_arg(char *extra_args, int buflen)
 491{
 492        char *val;
 493        int vallen;
 494        char *end = extra_args + buflen;
 495
 496        if (extra_args < end && *extra_args) {
 497                saw_extended_args = 1;
 498                if (strncasecmp("host=", extra_args, 5) == 0) {
 499                        val = extra_args + 5;
 500                        vallen = strlen(val) + 1;
 501                        if (*val) {
 502                                /* Split <host>:<port> at colon. */
 503                                char *host;
 504                                char *port;
 505                                parse_host_and_port(val, &host, &port);
 506                                if (port) {
 507                                        free(tcp_port);
 508                                        tcp_port = xstrdup(port);
 509                                }
 510                                free(hostname);
 511                                hostname = xstrdup_tolower(host);
 512                        }
 513
 514                        /* On to the next one */
 515                        extra_args = val + vallen;
 516                }
 517                if (extra_args < end && *extra_args)
 518                        die("Invalid request");
 519        }
 520
 521        /*
 522         * Locate canonical hostname and its IP address.
 523         */
 524        if (hostname) {
 525#ifndef NO_IPV6
 526                struct addrinfo hints;
 527                struct addrinfo *ai;
 528                int gai;
 529                static char addrbuf[HOST_NAME_MAX + 1];
 530
 531                memset(&hints, 0, sizeof(hints));
 532                hints.ai_flags = AI_CANONNAME;
 533
 534                gai = getaddrinfo(hostname, NULL, &hints, &ai);
 535                if (!gai) {
 536                        struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 537
 538                        inet_ntop(AF_INET, &sin_addr->sin_addr,
 539                                  addrbuf, sizeof(addrbuf));
 540                        free(ip_address);
 541                        ip_address = xstrdup(addrbuf);
 542
 543                        free(canon_hostname);
 544                        canon_hostname = xstrdup(ai->ai_canonname ?
 545                                                 ai->ai_canonname : ip_address);
 546
 547                        freeaddrinfo(ai);
 548                }
 549#else
 550                struct hostent *hent;
 551                struct sockaddr_in sa;
 552                char **ap;
 553                static char addrbuf[HOST_NAME_MAX + 1];
 554
 555                hent = gethostbyname(hostname);
 556                if (hent) {
 557                        ap = hent->h_addr_list;
 558                        memset(&sa, 0, sizeof sa);
 559                        sa.sin_family = hent->h_addrtype;
 560                        sa.sin_port = htons(0);
 561                        memcpy(&sa.sin_addr, *ap, hent->h_length);
 562
 563                        inet_ntop(hent->h_addrtype, &sa.sin_addr,
 564                                  addrbuf, sizeof(addrbuf));
 565
 566                        free(canon_hostname);
 567                        canon_hostname = xstrdup(hent->h_name);
 568                        free(ip_address);
 569                        ip_address = xstrdup(addrbuf);
 570                }
 571#endif
 572        }
 573}
 574
 575
 576static int execute(void)
 577{
 578        char *line = packet_buffer;
 579        int pktlen, len, i;
 580        char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
 581
 582        if (addr)
 583                loginfo("Connection from %s:%s", addr, port);
 584
 585        alarm(init_timeout ? init_timeout : timeout);
 586        pktlen = packet_read(0, NULL, NULL, packet_buffer, sizeof(packet_buffer), 0);
 587        alarm(0);
 588
 589        len = strlen(line);
 590        if (pktlen != len)
 591                loginfo("Extended attributes (%d bytes) exist <%.*s>",
 592                        (int) pktlen - len,
 593                        (int) pktlen - len, line + len + 1);
 594        if (len && line[len-1] == '\n') {
 595                line[--len] = 0;
 596                pktlen--;
 597        }
 598
 599        free(hostname);
 600        free(canon_hostname);
 601        free(ip_address);
 602        free(tcp_port);
 603        hostname = canon_hostname = ip_address = tcp_port = NULL;
 604
 605        if (len != pktlen)
 606                parse_host_arg(line + len + 1, pktlen - len - 1);
 607
 608        for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 609                struct daemon_service *s = &(daemon_service[i]);
 610                const char *arg;
 611
 612                if (skip_prefix(line, "git-", &arg) &&
 613                    skip_prefix(arg, s->name, &arg) &&
 614                    *arg++ == ' ') {
 615                        /*
 616                         * Note: The directory here is probably context sensitive,
 617                         * and might depend on the actual service being performed.
 618                         */
 619                        return run_service(arg, s);
 620                }
 621        }
 622
 623        logerror("Protocol error: '%s'", line);
 624        return -1;
 625}
 626
 627static int addrcmp(const struct sockaddr_storage *s1,
 628    const struct sockaddr_storage *s2)
 629{
 630        const struct sockaddr *sa1 = (const struct sockaddr*) s1;
 631        const struct sockaddr *sa2 = (const struct sockaddr*) s2;
 632
 633        if (sa1->sa_family != sa2->sa_family)
 634                return sa1->sa_family - sa2->sa_family;
 635        if (sa1->sa_family == AF_INET)
 636                return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
 637                    &((struct sockaddr_in *)s2)->sin_addr,
 638                    sizeof(struct in_addr));
 639#ifndef NO_IPV6
 640        if (sa1->sa_family == AF_INET6)
 641                return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
 642                    &((struct sockaddr_in6 *)s2)->sin6_addr,
 643                    sizeof(struct in6_addr));
 644#endif
 645        return 0;
 646}
 647
 648static int max_connections = 32;
 649
 650static unsigned int live_children;
 651
 652static struct child {
 653        struct child *next;
 654        struct child_process cld;
 655        struct sockaddr_storage address;
 656} *firstborn;
 657
 658static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
 659{
 660        struct child *newborn, **cradle;
 661
 662        newborn = xcalloc(1, sizeof(*newborn));
 663        live_children++;
 664        memcpy(&newborn->cld, cld, sizeof(*cld));
 665        memcpy(&newborn->address, addr, addrlen);
 666        for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
 667                if (!addrcmp(&(*cradle)->address, &newborn->address))
 668                        break;
 669        newborn->next = *cradle;
 670        *cradle = newborn;
 671}
 672
 673/*
 674 * This gets called if the number of connections grows
 675 * past "max_connections".
 676 *
 677 * We kill the newest connection from a duplicate IP.
 678 */
 679static void kill_some_child(void)
 680{
 681        const struct child *blanket, *next;
 682
 683        if (!(blanket = firstborn))
 684                return;
 685
 686        for (; (next = blanket->next); blanket = next)
 687                if (!addrcmp(&blanket->address, &next->address)) {
 688                        kill(blanket->cld.pid, SIGTERM);
 689                        break;
 690                }
 691}
 692
 693static void check_dead_children(void)
 694{
 695        int status;
 696        pid_t pid;
 697
 698        struct child **cradle, *blanket;
 699        for (cradle = &firstborn; (blanket = *cradle);)
 700                if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
 701                        const char *dead = "";
 702                        if (status)
 703                                dead = " (with error)";
 704                        loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
 705
 706                        /* remove the child */
 707                        *cradle = blanket->next;
 708                        live_children--;
 709                        free(blanket);
 710                } else
 711                        cradle = &blanket->next;
 712}
 713
 714static char **cld_argv;
 715static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 716{
 717        struct child_process cld = CHILD_PROCESS_INIT;
 718        char addrbuf[300] = "REMOTE_ADDR=", portbuf[300];
 719        char *env[] = { addrbuf, portbuf, NULL };
 720
 721        if (max_connections && live_children >= max_connections) {
 722                kill_some_child();
 723                sleep(1);  /* give it some time to die */
 724                check_dead_children();
 725                if (live_children >= max_connections) {
 726                        close(incoming);
 727                        logerror("Too many children, dropping connection");
 728                        return;
 729                }
 730        }
 731
 732        if (addr->sa_family == AF_INET) {
 733                struct sockaddr_in *sin_addr = (void *) addr;
 734                inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf + 12,
 735                    sizeof(addrbuf) - 12);
 736                snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 737                    ntohs(sin_addr->sin_port));
 738#ifndef NO_IPV6
 739        } else if (addr->sa_family == AF_INET6) {
 740                struct sockaddr_in6 *sin6_addr = (void *) addr;
 741
 742                char *buf = addrbuf + 12;
 743                *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
 744                inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf,
 745                    sizeof(addrbuf) - 13);
 746                strcat(buf, "]");
 747
 748                snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 749                    ntohs(sin6_addr->sin6_port));
 750#endif
 751        }
 752
 753        cld.env = (const char **)env;
 754        cld.argv = (const char **)cld_argv;
 755        cld.in = incoming;
 756        cld.out = dup(incoming);
 757
 758        if (start_command(&cld))
 759                logerror("unable to fork");
 760        else
 761                add_child(&cld, addr, addrlen);
 762}
 763
 764static void child_handler(int signo)
 765{
 766        /*
 767         * Otherwise empty handler because systemcalls will get interrupted
 768         * upon signal receipt
 769         * SysV needs the handler to be rearmed
 770         */
 771        signal(SIGCHLD, child_handler);
 772}
 773
 774static int set_reuse_addr(int sockfd)
 775{
 776        int on = 1;
 777
 778        if (!reuseaddr)
 779                return 0;
 780        return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
 781                          &on, sizeof(on));
 782}
 783
 784struct socketlist {
 785        int *list;
 786        size_t nr;
 787        size_t alloc;
 788};
 789
 790static const char *ip2str(int family, struct sockaddr *sin, socklen_t len)
 791{
 792#ifdef NO_IPV6
 793        static char ip[INET_ADDRSTRLEN];
 794#else
 795        static char ip[INET6_ADDRSTRLEN];
 796#endif
 797
 798        switch (family) {
 799#ifndef NO_IPV6
 800        case AF_INET6:
 801                inet_ntop(family, &((struct sockaddr_in6*)sin)->sin6_addr, ip, len);
 802                break;
 803#endif
 804        case AF_INET:
 805                inet_ntop(family, &((struct sockaddr_in*)sin)->sin_addr, ip, len);
 806                break;
 807        default:
 808                strcpy(ip, "<unknown>");
 809        }
 810        return ip;
 811}
 812
 813#ifndef NO_IPV6
 814
 815static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 816{
 817        int socknum = 0;
 818        char pbuf[NI_MAXSERV];
 819        struct addrinfo hints, *ai0, *ai;
 820        int gai;
 821        long flags;
 822
 823        sprintf(pbuf, "%d", listen_port);
 824        memset(&hints, 0, sizeof(hints));
 825        hints.ai_family = AF_UNSPEC;
 826        hints.ai_socktype = SOCK_STREAM;
 827        hints.ai_protocol = IPPROTO_TCP;
 828        hints.ai_flags = AI_PASSIVE;
 829
 830        gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
 831        if (gai) {
 832                logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
 833                return 0;
 834        }
 835
 836        for (ai = ai0; ai; ai = ai->ai_next) {
 837                int sockfd;
 838
 839                sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 840                if (sockfd < 0)
 841                        continue;
 842                if (sockfd >= FD_SETSIZE) {
 843                        logerror("Socket descriptor too large");
 844                        close(sockfd);
 845                        continue;
 846                }
 847
 848#ifdef IPV6_V6ONLY
 849                if (ai->ai_family == AF_INET6) {
 850                        int on = 1;
 851                        setsockopt(sockfd, IPPROTO_IPV6, IPV6_V6ONLY,
 852                                   &on, sizeof(on));
 853                        /* Note: error is not fatal */
 854                }
 855#endif
 856
 857                if (set_reuse_addr(sockfd)) {
 858                        logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 859                        close(sockfd);
 860                        continue;
 861                }
 862
 863                if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
 864                        logerror("Could not bind to %s: %s",
 865                                 ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 866                                 strerror(errno));
 867                        close(sockfd);
 868                        continue;       /* not fatal */
 869                }
 870                if (listen(sockfd, 5) < 0) {
 871                        logerror("Could not listen to %s: %s",
 872                                 ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
 873                                 strerror(errno));
 874                        close(sockfd);
 875                        continue;       /* not fatal */
 876                }
 877
 878                flags = fcntl(sockfd, F_GETFD, 0);
 879                if (flags >= 0)
 880                        fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 881
 882                ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 883                socklist->list[socklist->nr++] = sockfd;
 884                socknum++;
 885        }
 886
 887        freeaddrinfo(ai0);
 888
 889        return socknum;
 890}
 891
 892#else /* NO_IPV6 */
 893
 894static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 895{
 896        struct sockaddr_in sin;
 897        int sockfd;
 898        long flags;
 899
 900        memset(&sin, 0, sizeof sin);
 901        sin.sin_family = AF_INET;
 902        sin.sin_port = htons(listen_port);
 903
 904        if (listen_addr) {
 905                /* Well, host better be an IP address here. */
 906                if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
 907                        return 0;
 908        } else {
 909                sin.sin_addr.s_addr = htonl(INADDR_ANY);
 910        }
 911
 912        sockfd = socket(AF_INET, SOCK_STREAM, 0);
 913        if (sockfd < 0)
 914                return 0;
 915
 916        if (set_reuse_addr(sockfd)) {
 917                logerror("Could not set SO_REUSEADDR: %s", strerror(errno));
 918                close(sockfd);
 919                return 0;
 920        }
 921
 922        if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
 923                logerror("Could not bind to %s: %s",
 924                         ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
 925                         strerror(errno));
 926                close(sockfd);
 927                return 0;
 928        }
 929
 930        if (listen(sockfd, 5) < 0) {
 931                logerror("Could not listen to %s: %s",
 932                         ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
 933                         strerror(errno));
 934                close(sockfd);
 935                return 0;
 936        }
 937
 938        flags = fcntl(sockfd, F_GETFD, 0);
 939        if (flags >= 0)
 940                fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 941
 942        ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 943        socklist->list[socklist->nr++] = sockfd;
 944        return 1;
 945}
 946
 947#endif
 948
 949static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
 950{
 951        if (!listen_addr->nr)
 952                setup_named_sock(NULL, listen_port, socklist);
 953        else {
 954                int i, socknum;
 955                for (i = 0; i < listen_addr->nr; i++) {
 956                        socknum = setup_named_sock(listen_addr->items[i].string,
 957                                                   listen_port, socklist);
 958
 959                        if (socknum == 0)
 960                                logerror("unable to allocate any listen sockets for host %s on port %u",
 961                                         listen_addr->items[i].string, listen_port);
 962                }
 963        }
 964}
 965
 966static int service_loop(struct socketlist *socklist)
 967{
 968        struct pollfd *pfd;
 969        int i;
 970
 971        pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
 972
 973        for (i = 0; i < socklist->nr; i++) {
 974                pfd[i].fd = socklist->list[i];
 975                pfd[i].events = POLLIN;
 976        }
 977
 978        signal(SIGCHLD, child_handler);
 979
 980        for (;;) {
 981                int i;
 982
 983                check_dead_children();
 984
 985                if (poll(pfd, socklist->nr, -1) < 0) {
 986                        if (errno != EINTR) {
 987                                logerror("Poll failed, resuming: %s",
 988                                      strerror(errno));
 989                                sleep(1);
 990                        }
 991                        continue;
 992                }
 993
 994                for (i = 0; i < socklist->nr; i++) {
 995                        if (pfd[i].revents & POLLIN) {
 996                                union {
 997                                        struct sockaddr sa;
 998                                        struct sockaddr_in sai;
 999#ifndef NO_IPV6
1000                                        struct sockaddr_in6 sai6;
1001#endif
1002                                } ss;
1003                                socklen_t sslen = sizeof(ss);
1004                                int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
1005                                if (incoming < 0) {
1006                                        switch (errno) {
1007                                        case EAGAIN:
1008                                        case EINTR:
1009                                        case ECONNABORTED:
1010                                                continue;
1011                                        default:
1012                                                die_errno("accept returned");
1013                                        }
1014                                }
1015                                handle(incoming, &ss.sa, sslen);
1016                        }
1017                }
1018        }
1019}
1020
1021#ifdef NO_POSIX_GOODIES
1022
1023struct credentials;
1024
1025static void drop_privileges(struct credentials *cred)
1026{
1027        /* nothing */
1028}
1029
1030static struct credentials *prepare_credentials(const char *user_name,
1031    const char *group_name)
1032{
1033        die("--user not supported on this platform");
1034}
1035
1036#else
1037
1038struct credentials {
1039        struct passwd *pass;
1040        gid_t gid;
1041};
1042
1043static void drop_privileges(struct credentials *cred)
1044{
1045        if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
1046            setgid (cred->gid) || setuid(cred->pass->pw_uid)))
1047                die("cannot drop privileges");
1048}
1049
1050static struct credentials *prepare_credentials(const char *user_name,
1051    const char *group_name)
1052{
1053        static struct credentials c;
1054
1055        c.pass = getpwnam(user_name);
1056        if (!c.pass)
1057                die("user not found - %s", user_name);
1058
1059        if (!group_name)
1060                c.gid = c.pass->pw_gid;
1061        else {
1062                struct group *group = getgrnam(group_name);
1063                if (!group)
1064                        die("group not found - %s", group_name);
1065
1066                c.gid = group->gr_gid;
1067        }
1068
1069        return &c;
1070}
1071#endif
1072
1073static void store_pid(const char *path)
1074{
1075        FILE *f = fopen(path, "w");
1076        if (!f)
1077                die_errno("cannot open pid file '%s'", path);
1078        if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
1079                die_errno("failed to write pid file '%s'", path);
1080}
1081
1082static int serve(struct string_list *listen_addr, int listen_port,
1083    struct credentials *cred)
1084{
1085        struct socketlist socklist = { NULL, 0, 0 };
1086
1087        socksetup(listen_addr, listen_port, &socklist);
1088        if (socklist.nr == 0)
1089                die("unable to allocate any listen sockets on port %u",
1090                    listen_port);
1091
1092        drop_privileges(cred);
1093
1094        loginfo("Ready to rumble");
1095
1096        return service_loop(&socklist);
1097}
1098
1099int main(int argc, char **argv)
1100{
1101        int listen_port = 0;
1102        struct string_list listen_addr = STRING_LIST_INIT_NODUP;
1103        int serve_mode = 0, inetd_mode = 0;
1104        const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
1105        int detach = 0;
1106        struct credentials *cred = NULL;
1107        int i;
1108
1109        git_setup_gettext();
1110
1111        git_extract_argv0_path(argv[0]);
1112
1113        for (i = 1; i < argc; i++) {
1114                char *arg = argv[i];
1115                const char *v;
1116
1117                if (skip_prefix(arg, "--listen=", &v)) {
1118                        string_list_append(&listen_addr, xstrdup_tolower(v));
1119                        continue;
1120                }
1121                if (skip_prefix(arg, "--port=", &v)) {
1122                        char *end;
1123                        unsigned long n;
1124                        n = strtoul(v, &end, 0);
1125                        if (*v && !*end) {
1126                                listen_port = n;
1127                                continue;
1128                        }
1129                }
1130                if (!strcmp(arg, "--serve")) {
1131                        serve_mode = 1;
1132                        continue;
1133                }
1134                if (!strcmp(arg, "--inetd")) {
1135                        inetd_mode = 1;
1136                        log_syslog = 1;
1137                        continue;
1138                }
1139                if (!strcmp(arg, "--verbose")) {
1140                        verbose = 1;
1141                        continue;
1142                }
1143                if (!strcmp(arg, "--syslog")) {
1144                        log_syslog = 1;
1145                        continue;
1146                }
1147                if (!strcmp(arg, "--export-all")) {
1148                        export_all_trees = 1;
1149                        continue;
1150                }
1151                if (skip_prefix(arg, "--access-hook=", &v)) {
1152                        access_hook = v;
1153                        continue;
1154                }
1155                if (skip_prefix(arg, "--timeout=", &v)) {
1156                        timeout = atoi(v);
1157                        continue;
1158                }
1159                if (skip_prefix(arg, "--init-timeout=", &v)) {
1160                        init_timeout = atoi(v);
1161                        continue;
1162                }
1163                if (skip_prefix(arg, "--max-connections=", &v)) {
1164                        max_connections = atoi(v);
1165                        if (max_connections < 0)
1166                                max_connections = 0;            /* unlimited */
1167                        continue;
1168                }
1169                if (!strcmp(arg, "--strict-paths")) {
1170                        strict_paths = 1;
1171                        continue;
1172                }
1173                if (skip_prefix(arg, "--base-path=", &v)) {
1174                        base_path = v;
1175                        continue;
1176                }
1177                if (!strcmp(arg, "--base-path-relaxed")) {
1178                        base_path_relaxed = 1;
1179                        continue;
1180                }
1181                if (skip_prefix(arg, "--interpolated-path=", &v)) {
1182                        interpolated_path = v;
1183                        continue;
1184                }
1185                if (!strcmp(arg, "--reuseaddr")) {
1186                        reuseaddr = 1;
1187                        continue;
1188                }
1189                if (!strcmp(arg, "--user-path")) {
1190                        user_path = "";
1191                        continue;
1192                }
1193                if (skip_prefix(arg, "--user-path=", &v)) {
1194                        user_path = v;
1195                        continue;
1196                }
1197                if (skip_prefix(arg, "--pid-file=", &v)) {
1198                        pid_file = v;
1199                        continue;
1200                }
1201                if (!strcmp(arg, "--detach")) {
1202                        detach = 1;
1203                        log_syslog = 1;
1204                        continue;
1205                }
1206                if (skip_prefix(arg, "--user=", &v)) {
1207                        user_name = v;
1208                        continue;
1209                }
1210                if (skip_prefix(arg, "--group=", &v)) {
1211                        group_name = v;
1212                        continue;
1213                }
1214                if (skip_prefix(arg, "--enable=", &v)) {
1215                        enable_service(v, 1);
1216                        continue;
1217                }
1218                if (skip_prefix(arg, "--disable=", &v)) {
1219                        enable_service(v, 0);
1220                        continue;
1221                }
1222                if (skip_prefix(arg, "--allow-override=", &v)) {
1223                        make_service_overridable(v, 1);
1224                        continue;
1225                }
1226                if (skip_prefix(arg, "--forbid-override=", &v)) {
1227                        make_service_overridable(v, 0);
1228                        continue;
1229                }
1230                if (!strcmp(arg, "--informative-errors")) {
1231                        informative_errors = 1;
1232                        continue;
1233                }
1234                if (!strcmp(arg, "--no-informative-errors")) {
1235                        informative_errors = 0;
1236                        continue;
1237                }
1238                if (!strcmp(arg, "--")) {
1239                        ok_paths = &argv[i+1];
1240                        break;
1241                } else if (arg[0] != '-') {
1242                        ok_paths = &argv[i];
1243                        break;
1244                }
1245
1246                usage(daemon_usage);
1247        }
1248
1249        if (log_syslog) {
1250                openlog("git-daemon", LOG_PID, LOG_DAEMON);
1251                set_die_routine(daemon_die);
1252        } else
1253                /* avoid splitting a message in the middle */
1254                setvbuf(stderr, NULL, _IOFBF, 4096);
1255
1256        if (inetd_mode && (detach || group_name || user_name))
1257                die("--detach, --user and --group are incompatible with --inetd");
1258
1259        if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
1260                die("--listen= and --port= are incompatible with --inetd");
1261        else if (listen_port == 0)
1262                listen_port = DEFAULT_GIT_PORT;
1263
1264        if (group_name && !user_name)
1265                die("--group supplied without --user");
1266
1267        if (user_name)
1268                cred = prepare_credentials(user_name, group_name);
1269
1270        if (strict_paths && (!ok_paths || !*ok_paths))
1271                die("option --strict-paths requires a whitelist");
1272
1273        if (base_path && !is_directory(base_path))
1274                die("base-path '%s' does not exist or is not a directory",
1275                    base_path);
1276
1277        if (inetd_mode) {
1278                if (!freopen("/dev/null", "w", stderr))
1279                        die_errno("failed to redirect stderr to /dev/null");
1280        }
1281
1282        if (inetd_mode || serve_mode)
1283                return execute();
1284
1285        if (detach) {
1286                if (daemonize())
1287                        die("--detach not supported on this platform");
1288        } else
1289                sanitize_stdfds();
1290
1291        if (pid_file)
1292                store_pid(pid_file);
1293
1294        /* prepare argv for serving-processes */
1295        cld_argv = xmalloc(sizeof (char *) * (argc + 2));
1296        cld_argv[0] = argv[0];  /* git-daemon */
1297        cld_argv[1] = "--serve";
1298        for (i = 1; i < argc; ++i)
1299                cld_argv[i+1] = argv[i];
1300        cld_argv[argc+1] = NULL;
1301
1302        return serve(&listen_addr, listen_port, cred);
1303}