server.c

   1 /* Copyright (C) 1997 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
   2
   3 /** \file server.c Paraslash's main server. */
   4
   5 #include <netinet/in.h>
   6 #include <sys/socket.h>
   7 #include <signal.h>
   8 #include <regex.h>
   9 #include <osl.h>
  10 #include <sys/types.h>
  11 #include <arpa/inet.h>
  12 #include <sys/un.h>
  13 #include <netdb.h>
  14 #include <lopsub.h>
  15
  16 #include "server.lsg.h"
  17 #include "para.h"
  18 #include "error.h"
  19 #include "lsu.h"
  20 #include "crypt.h"
  21 #include "afh.h"
  22 #include "string.h"
  23 #include "afs.h"
  24 #include "net.h"
  25 #include "server.h"
  26 #include "list.h"
  27 #include "send.h"
  28 #include "sched.h"
  29 #include "vss.h"
  30 #include "config.h"
  31 #include "close_on_fork.h"
  32 #include "daemon.h"
  33 #include "ipc.h"
  34 #include "fd.h"
  35 #include "signal.h"
  36 #include "user_list.h"
  37 #include "color.h"
  38 #include "version.h"
  39
  40 /** Array of error strings. */
  41 DEFINE_PARA_ERRLIST;
  42
  43 __printf_2_3 void (*para_log)(int, const char*, ...) = daemon_log;
  44
  45 /** Shut down non-authorized connections after that many seconds. */
  46 #define ALARM_TIMEOUT 10
  47
  48 /**
  49  * Pointer to shared memory area for communication between para_server
  50  * and its children. Exported to vss.c, command.c and to afs.
  51  */
  52 struct misc_meta_data *mmd;
  53
  54 /**
  55  * The active value for all config options of para_server.
  56  *
  57  * It is computed by merging the parse result of the command line options with
  58  * the parse result of the config file.
  59  */
  60 struct lls_parse_result *server_lpr = NULL;
  61
  62 /* Command line options (no config file options). Used in handle_sighup(). */
  63 static struct lls_parse_result *cmdline_lpr;
  64
  65 /**
  66  * A random number used to "authenticate" the afs connection.
  67  *
  68  * para_server picks this number by random before it forks the afs process. The
  69  * command handlers know this number as well and write it to the afs socket,
  70  * together with the id of the shared memory area which contains the payload of
  71  * the afs command. A local process has to know this number to abuse the afs
  72  * service provided by the local socket.
  73  */
  74 uint32_t afs_socket_cookie;
  75
  76 /** The mutex protecting the shared memory area containing the mmd struct. */
  77 int mmd_mutex;
  78
  79 /* Serializes log output. */
  80 static int log_mutex;
  81
  82 static struct sched sched;
  83 static struct signal_task *signal_task;
  84
  85 /** The process id of the audio file selector process. */
  86 pid_t afs_pid = 0;
  87
  88 /* The main server process (parent of afs and the command handlers). */
  89 static pid_t server_pid;
  90
  91 /**
  92  * Tell whether the executing process is a command handler.
  93  *
  94  * Cleanup on exit must be performed differently for command handlers.
  95  *
  96  * \return True if the pid of the executing process is neither the server pid
  97  * nor the afs pid.
  98  */
  99 bool process_is_command_handler(void)
 100 {
 101         pid_t pid = getpid();
 102
 103         return pid != afs_pid && pid != server_pid;
 104 }
 105
 106 /** The task responsible for server command handling. */
 107 struct server_command_task {
 108         unsigned num_listen_fds; /* only one by default */
 109         /** TCP socket(s) on which para_server listens for connections. */
 110         int *listen_fds;
 111         /* File descriptor for the accepted socket. */
 112         int child_fd;
 113         /** Copied from para_server's main function. */
 114         int argc;
 115         /** Argument vector passed to para_server's main function. */
 116         char **argv;
 117         /** The command task structure for scheduling. */
 118         struct task *task;
 119 };
 120
 121 /**
 122  * Return the list of tasks for the server process.
 123  *
 124  * This is called from \a com_tasks(). The helper is necessary since command
 125  * handlers can not access the scheduler structure directly.
 126  *
 127  * \return A dynamically allocated string that must be freed by the caller.
 128  */
 129 char *server_get_tasks(void)
 130 {
 131         return get_task_list(&sched);
 132 }
 133
 134 static void pre_log_hook(void)
 135 {
 136         mutex_lock(log_mutex);
 137 }
 138
 139 static void post_log_hook(void)
 140 {
 141         mutex_unlock(log_mutex);
 142 }
 143
 144 /* Setup shared memory area and init mutexes */
 145 static void init_ipc_or_die(void)
 146 {
 147         void *shm;
 148         int shmid, ret = shm_new(sizeof(struct misc_meta_data));
 149
 150         if (ret < 0)
 151                 goto err_out;
 152         shmid = ret;
 153         ret = shm_attach(shmid, ATTACH_RW, &shm);
 154         shm_destroy(shmid);
 155         if (ret < 0)
 156                 goto err_out;
 157         mmd = shm;
 158
 159         ret = mutex_new();
 160         if (ret < 0)
 161                 goto err_out;
 162         mmd_mutex = ret;
 163         ret = mutex_new();
 164         if (ret < 0)
 165                 goto destroy_mmd_mutex;
 166         log_mutex = ret;
 167
 168         mmd->num_played = 0;
 169         mmd->num_commands = 0;
 170         mmd->events = 0;
 171         mmd->num_connects = 0;
 172         mmd->active_connections = 0;
 173         mmd->vss_status_flags = VSS_NEXT;
 174         mmd->new_vss_status_flags = VSS_NEXT;
 175         return;
 176 destroy_mmd_mutex:
 177         mutex_destroy(mmd_mutex);
 178 err_out:
 179         PARA_EMERG_LOG("%s\n", para_strerror(-ret));
 180         exit(EXIT_FAILURE);
 181 }
 182
 183 /**
 184  * (Re-)read the server configuration files.
 185  *
 186  * \param reload Whether config file overrides command line.
 187  *
 188  * This function also re-opens the logfile and the user list. On SIGHUP it is
 189  * called from both server and afs context.
 190  */
 191 void parse_config_or_die(bool reload)
 192 {
 193         int ret;
 194         unsigned flags = MCF_DONT_FREE;
 195
 196         if (server_lpr != cmdline_lpr)
 197                 lls_free_parse_result(server_lpr, CMD_PTR);
 198         server_lpr = cmdline_lpr;
 199         if (reload)
 200                 flags |= MCF_OVERRIDE;
 201         ret = lsu_merge_config_file_options(OPT_STRING_VAL(CONFIG_FILE),
 202                 "server.conf", &server_lpr, CMD_PTR, server_suite, flags);
 203         if (ret < 0) {
 204                 PARA_EMERG_LOG("failed to parse config file: %s\n",
 205                         para_strerror(-ret));
 206                 exit(EXIT_FAILURE);
 207         }
 208         daemon_set_loglevel(ENUM_STRING_VAL(LOGLEVEL));
 209         if (OPT_GIVEN(LOGFILE)) {
 210                 daemon_set_logfile(OPT_STRING_VAL(LOGFILE));
 211                 daemon_open_log_or_die();
 212         }
 213         if (daemon_init_colors_or_die(OPT_UINT32_VAL(COLOR), COLOR_AUTO,
 214                         COLOR_NO, OPT_GIVEN(LOGFILE))) {
 215                 int i;
 216                 for (i = 0; i < OPT_GIVEN(LOG_COLOR); i++)
 217                         daemon_set_log_color_or_die(lls_string_val(i,
 218                                 OPT_RESULT(LOG_COLOR)));
 219         }
 220         daemon_set_flag(DF_LOG_PID);
 221         daemon_set_flag(DF_LOG_LL);
 222         daemon_set_flag(DF_LOG_TIME);
 223         if (OPT_GIVEN(LOG_TIMING))
 224                 daemon_set_flag(DF_LOG_TIMING);
 225         daemon_set_priority(OPT_UINT32_VAL(PRIORITY));
 226         if (!reload || getpid() != afs_pid) {
 227                 char *user_list_file;
 228                 if (OPT_GIVEN(USER_LIST))
 229                         user_list_file = para_strdup(OPT_STRING_VAL(USER_LIST));
 230                 else {
 231                         char *home = para_homedir();
 232                         user_list_file = make_message("%s/.paraslash/server.users", home);
 233                         free(home);
 234                 }
 235                 user_list_init(user_list_file);
 236                 free(user_list_file);
 237         }
 238         return;
 239 }
 240
 241 /*
 242  * called when server gets SIGHUP or when client invokes hup command.
 243  */
 244 static void handle_sighup(void)
 245 {
 246
 247         PARA_NOTICE_LOG("SIGHUP\n");
 248         parse_config_or_die(true);
 249         if (afs_pid != 0)
 250                 kill(afs_pid, SIGHUP);
 251 }
 252
 253 static int signal_post_select(struct sched *s, __a_unused void *context)
 254 {
 255         int ret, signum;
 256
 257         ret = task_get_notification(signal_task->task);
 258         if (ret < 0)
 259                 return ret;
 260         signum = para_next_signal(&s->rfds);
 261         switch (signum) {
 262         case 0:
 263                 return 0;
 264         case SIGHUP:
 265                 handle_sighup();
 266                 break;
 267         case SIGCHLD:
 268                 for (;;) {
 269                         pid_t pid;
 270                         ret = para_reap_child(&pid);
 271                         if (ret <= 0)
 272                                 break;
 273                         if (pid != afs_pid)
 274                                 continue;
 275                         PARA_EMERG_LOG("fatal: afs died\n");
 276                         goto genocide;
 277                 }
 278                 break;
 279         /* die on sigint/sigterm. Kill all children too. */
 280         case SIGINT:
 281         case SIGTERM:
 282                 PARA_EMERG_LOG("terminating on signal %d\n", signum);
 283 genocide:
 284                 kill(0, SIGTERM);
 285                 /*
 286                  * We must wait for all of our children to die. For the afs
 287                  * process or a command handler might want to use the
 288                  * shared memory area and the mmd mutex.  If we destroy this
 289                  * mutex too early and afs tries to lock the shared memory
 290                  * area, the call to mutex_lock() will fail and terminate the
 291                  * afs process. This leads to dirty osl tables.
 292                  */
 293                 PARA_INFO_LOG("waiting for child processes to die\n");
 294                 mutex_unlock(mmd_mutex);
 295                 while (wait(NULL) != -1 || errno != ECHILD)
 296                         ; /* still at least one child alive */
 297                 mutex_lock(mmd_mutex);
 298                 free(mmd->afd.afhi.chunk_table);
 299                 task_notify_all(s, E_DEADLY_SIGNAL);
 300                 return -E_DEADLY_SIGNAL;
 301         }
 302         return 0;
 303 }
 304
 305 static void init_signal_task(void)
 306 {
 307         signal_task = signal_init_or_die();
 308         para_install_sighandler(SIGINT);
 309         para_install_sighandler(SIGTERM);
 310         para_install_sighandler(SIGHUP);
 311         para_install_sighandler(SIGCHLD);
 312         para_sigaction(SIGPIPE, SIG_IGN);
 313         add_close_on_fork_list(signal_task->fd);
 314         signal_task->task = task_register(&(struct task_info) {
 315                 .name = "signal",
 316                 .pre_select = signal_pre_select,
 317                 .post_select = signal_post_select,
 318                 .context = signal_task,
 319
 320         }, &sched);
 321 }
 322
 323 static void command_pre_select(struct sched *s, void *context)
 324 {
 325         unsigned n;
 326         struct server_command_task *sct = context;
 327
 328         for (n = 0; n < sct->num_listen_fds; n++)
 329                 para_fd_set(sct->listen_fds[n], &s->rfds, &s->max_fileno);
 330 }
 331
 332 static int command_task_accept(unsigned listen_idx, struct sched *s,
 333                 struct server_command_task *sct)
 334 {
 335         int new_fd, ret, i;
 336         char *peer_name;
 337         pid_t child_pid;
 338         uint32_t *chunk_table;
 339
 340         ret = para_accept(sct->listen_fds[listen_idx], &s->rfds, NULL, 0, &new_fd);
 341         if (ret <= 0)
 342                 goto out;
 343         mmd->num_connects++;
 344         mmd->active_connections++;
 345         /*
 346          * The chunk table is a pointer located in the mmd struct that points
 347          * to dynamically allocated memory, i.e. it must be freed by the parent
 348          * and the child. However, as the mmd struct is in a shared memory
 349          * area, there's no guarantee that after the fork this pointer is still
 350          * valid in child context. As it is not used in the child anyway, we
 351          * save it to a local variable before the fork and free the memory via
 352          * that copy in the child directly after the fork.
 353          */
 354         chunk_table = mmd->afd.afhi.chunk_table;
 355         child_pid = fork();
 356         if (child_pid < 0) {
 357                 ret = -ERRNO_TO_PARA_ERROR(errno);
 358                 goto out;
 359         }
 360         if (child_pid) {
 361                 /* avoid problems with non-fork-safe PRNGs */
 362                 unsigned char buf[16];
 363                 get_random_bytes_or_die(buf, sizeof(buf));
 364                 close(new_fd);
 365                 /* parent keeps accepting connections */
 366                 return 0;
 367         }
 368         peer_name = remote_name(new_fd);
 369         PARA_INFO_LOG("accepted connection from %s\n", peer_name);
 370         /* mmd might already have changed at this point */
 371         free(chunk_table);
 372         sct->child_fd = new_fd;
 373         /*
 374          * put info on who we are serving into argv[0] to make
 375          * client ip visible in top/ps
 376          */
 377         for (i = sct->argc - 1; i >= 0; i--)
 378                 memset(sct->argv[i], 0, strlen(sct->argv[i]));
 379         i = sct->argc - 1 - lls_num_inputs(cmdline_lpr);
 380         sprintf(sct->argv[i], "para_server (serving %s)", peer_name);
 381         /* ask other tasks to terminate */
 382         task_notify_all(s, E_CHILD_CONTEXT);
 383         /*
 384          * After we return, the scheduler calls server_select() with a minimal
 385          * timeout value, because the remaining tasks have a notification
 386          * pending. Next it calls the ->post_select method of these tasks,
 387          * which will return negative in view of the notification. This causes
 388          * schedule() to return as there are no more runnable tasks.
 389          *
 390          * Note that semaphores are not inherited across a fork(), so we don't
 391          * hold the lock at this point. Since server_select() drops the lock
 392          * prior to calling para_select(), we need to acquire it here.
 393          */
 394         mutex_lock(mmd_mutex);
 395         return -E_CHILD_CONTEXT;
 396 out:
 397         if (ret < 0)
 398                 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
 399         return 0;
 400 }
 401
 402 static int command_post_select(struct sched *s, void *context)
 403 {
 404         struct server_command_task *sct = context;
 405         unsigned n;
 406         int ret;
 407
 408         ret = task_get_notification(sct->task);
 409         if (ret < 0)
 410                 goto fail;
 411         for (n = 0; n < sct->num_listen_fds; n++) {
 412                 ret = command_task_accept(n, s, sct);
 413                 if (ret < 0)
 414                         goto fail;
 415         }
 416         return 0;
 417 fail:
 418         free(sct->listen_fds);
 419         return ret;
 420 }
 421
 422 static void init_server_command_task(struct server_command_task *sct,
 423                 int argc, char **argv)
 424 {
 425         int ret;
 426         unsigned n;
 427         uint32_t port = OPT_UINT32_VAL(PORT);
 428
 429         PARA_NOTICE_LOG("initializing tcp command socket\n");
 430         sct->child_fd = -1;
 431         sct->argc = argc;
 432         sct->argv = argv;
 433         if (!OPT_GIVEN(LISTEN_ADDRESS)) {
 434                 sct->num_listen_fds = 1;
 435                 sct->listen_fds = para_malloc(sizeof(int));
 436                 ret = para_listen_simple(IPPROTO_TCP, port);
 437                 if (ret < 0)
 438                         goto err;
 439                 sct->listen_fds[0] = ret;
 440         } else {
 441                 sct->num_listen_fds = OPT_GIVEN(LISTEN_ADDRESS);
 442                 sct->listen_fds = para_malloc(sct->num_listen_fds * sizeof(int));
 443                 for (n = 0; n < OPT_GIVEN(LISTEN_ADDRESS); n++) {
 444                         const char *arg;
 445                         arg = lls_string_val(n, OPT_RESULT(LISTEN_ADDRESS));
 446                         ret = para_listen(IPPROTO_TCP, arg, port);
 447                         if (ret < 0)
 448                                 goto err;
 449                         sct->listen_fds[n] = ret;
 450                 }
 451         }
 452         for (n = 0; n < sct->num_listen_fds; n++) {
 453                 ret = mark_fd_nonblocking(sct->listen_fds[n]);
 454                 if (ret < 0)
 455                         goto err;
 456                 /* child doesn't need the listener */
 457                 add_close_on_fork_list(sct->listen_fds[n]);
 458         }
 459
 460         sct->task = task_register(&(struct task_info) {
 461                 .name = "server command",
 462                 .pre_select = command_pre_select,
 463                 .post_select = command_post_select,
 464                 .context = sct,
 465         }, &sched);
 466         /*
 467          * Detect whether the abstract Unix domain socket space is supported,
 468          * but do not create the socket. We check this once in server context
 469          * so that the command handlers inherit this bit of information and
 470          * don't need to check again.
 471          */
 472         create_local_socket(NULL);
 473         return;
 474 err:
 475         PARA_EMERG_LOG("%s\n", para_strerror(-ret));
 476         exit(EXIT_FAILURE);
 477 }
 478
 479 static int init_afs(int argc, char **argv)
 480 {
 481         int ret, afs_server_socket[2];
 482         char c;
 483
 484         ret = socketpair(PF_UNIX, SOCK_STREAM, 0, afs_server_socket);
 485         if (ret < 0)
 486                 exit(EXIT_FAILURE);
 487         get_random_bytes_or_die((unsigned char *)&afs_socket_cookie,
 488                 sizeof(afs_socket_cookie));
 489         afs_pid = fork();
 490         if (afs_pid < 0)
 491                 exit(EXIT_FAILURE);
 492         if (afs_pid == 0) { /* child (afs) */
 493                 int i;
 494
 495                 afs_pid = getpid();
 496                 crypt_shutdown();
 497                 user_list_deplete();
 498                 for (i = argc - 1; i >= 0; i--)
 499                         memset(argv[i], 0, strlen(argv[i]));
 500                 i = argc - lls_num_inputs(cmdline_lpr) - 1;
 501                 sprintf(argv[i], "para_server (afs)");
 502                 close(afs_server_socket[0]);
 503                 afs_init(afs_server_socket[1]);
 504         }
 505         close(afs_server_socket[1]);
 506         if (read(afs_server_socket[0], &c, 1) <= 0) {
 507                 PARA_EMERG_LOG("early afs exit\n");
 508                 exit(EXIT_FAILURE);
 509         }
 510         ret = mark_fd_nonblocking(afs_server_socket[0]);
 511         if (ret < 0)
 512                 exit(EXIT_FAILURE);
 513         add_close_on_fork_list(afs_server_socket[0]);
 514         PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
 515                 afs_server_socket[0], (unsigned) afs_socket_cookie);
 516         return afs_server_socket[0];
 517 }
 518
 519 static void handle_help_flags(void)
 520 {
 521         char *help;
 522         bool d = OPT_GIVEN(DETAILED_HELP);
 523
 524         if (d)
 525                 help = lls_long_help(CMD_PTR);
 526         else if (OPT_GIVEN(HELP))
 527                 help = lls_short_help(CMD_PTR);
 528         else
 529                 return;
 530         printf("%s\n", help);
 531         free(help);
 532         exit(EXIT_SUCCESS);
 533 }
 534
 535 static void server_init(int argc, char **argv, struct server_command_task *sct)
 536 {
 537         int ret, afs_socket, daemon_pipe = -1;
 538         char *errctx;
 539
 540         valid_fd_012();
 541         /* parse command line options */
 542         ret = lls(lls_parse(argc, argv, CMD_PTR, &cmdline_lpr, &errctx));
 543         if (ret < 0)
 544                 goto fail;
 545         server_lpr = cmdline_lpr;
 546         daemon_set_loglevel(ENUM_STRING_VAL(LOGLEVEL));
 547         daemon_drop_privileges_or_die(OPT_STRING_VAL(USER),
 548                 OPT_STRING_VAL(GROUP));
 549         version_handle_flag("server", OPT_GIVEN(VERSION));
 550         handle_help_flags();
 551         parse_config_or_die(false);
 552         /* become daemon */
 553         if (OPT_GIVEN(DAEMON))
 554                 daemon_pipe = daemonize(true /* parent waits for SIGTERM */);
 555         server_pid = getpid();
 556         crypt_init();
 557         daemon_log_welcome("server");
 558         init_ipc_or_die(); /* init mmd struct, mmd and log mutex */
 559         daemon_set_start_time();
 560         daemon_set_hooks(pre_log_hook, post_log_hook);
 561         /*
 562          * Although afs uses its own signal handling we must ignore SIGUSR1
 563          * _before_ the afs child process gets born by init_afs() below.  It's
 564          * racy to do this in the child because the parent might send SIGUSR1
 565          * before the child gets a chance to ignore this signal.
 566          *
 567          * We also have to block SIGCHLD before the afs process is created
 568          * because otherwise para_server does not notice if afs dies before the
 569          * SIGCHLD handler has been installed for the parent process by
 570          * init_signal_task() below.
 571          */
 572         para_sigaction(SIGUSR1, SIG_IGN);
 573         para_block_signal(SIGCHLD);
 574         PARA_NOTICE_LOG("initializing the audio file selector\n");
 575         afs_socket = init_afs(argc, argv);
 576         init_signal_task();
 577         para_unblock_signal(SIGCHLD);
 578         PARA_NOTICE_LOG("initializing virtual streaming system\n");
 579         vss_init(afs_socket, &sched);
 580         init_server_command_task(sct, argc, argv);
 581         if (daemon_pipe >= 0) {
 582                 if (write(daemon_pipe, "\0", 1) < 0) {
 583                         PARA_EMERG_LOG("daemon_pipe: %s", strerror(errno));
 584                         exit(EXIT_FAILURE);
 585                 }
 586                 close(daemon_pipe);
 587         }
 588         PARA_NOTICE_LOG("server init complete\n");
 589         return;
 590 fail:
 591         assert(ret < 0);
 592         if (errctx)
 593                 PARA_ERROR_LOG("%s\n", errctx);
 594         PARA_EMERG_LOG("%s\n", para_strerror(-ret));
 595         exit(EXIT_FAILURE);
 596 }
 597
 598 static void status_refresh(void)
 599 {
 600         static int prev_uptime = -1, prev_events = -1;
 601         int uptime = daemon_get_uptime(now);
 602
 603         if (prev_events != mmd->events)
 604                 goto out;
 605         if (mmd->new_vss_status_flags != mmd->vss_status_flags)
 606                 goto out_inc_events;
 607         if (uptime / 60 != prev_uptime / 60)
 608                 goto out_inc_events;
 609         return;
 610 out_inc_events:
 611         mmd->events++;
 612 out:
 613         prev_uptime = uptime;
 614         prev_events = mmd->events;
 615         mmd->vss_status_flags = mmd->new_vss_status_flags;
 616         PARA_DEBUG_LOG("%u events, forcing status update\n", mmd->events);
 617         killpg(0, SIGUSR1);
 618 }
 619
 620 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
 621                 struct timeval *timeout_tv)
 622 {
 623         int ret;
 624
 625         status_refresh();
 626         mutex_unlock(mmd_mutex);
 627         ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
 628         mutex_lock(mmd_mutex);
 629         return ret;
 630 }
 631
 632 /**
 633  * Deallocate all lopsub parse results.
 634  *
 635  * The server allocates a parse result for command line options and optionally
 636  * a second parse result for the effective configuration, defined by merging
 637  * the command line options with the options stored in the configuration file.
 638  * This function frees both structures.
 639  */
 640 void free_lpr(void)
 641 {
 642         lls_free_parse_result(server_lpr, CMD_PTR);
 643         if (server_lpr != cmdline_lpr)
 644                 lls_free_parse_result(cmdline_lpr, CMD_PTR);
 645 }
 646
 647 /**
 648  * The main function of para_server.
 649  *
 650  * \param argc Usual argument count.
 651  * \param argv Usual argument vector.
 652  *
 653  * \return EXIT_SUCCESS or EXIT_FAILURE.
 654  */
 655 int main(int argc, char *argv[])
 656 {
 657         int ret;
 658         struct server_command_task server_command_task_struct,
 659                 *sct = &server_command_task_struct;
 660
 661         sched.default_timeout.tv_sec = 1;
 662         sched.select_function = server_select;
 663
 664         server_init(argc, argv, sct);
 665         mutex_lock(mmd_mutex);
 666         ret = schedule(&sched);
 667         /*
 668          * We hold the mmd lock: it was re-acquired in server_select()
 669          * after the select call.
 670          */
 671         mutex_unlock(mmd_mutex);
 672         sched_shutdown(&sched);
 673         crypt_shutdown();
 674         signal_shutdown(signal_task);
 675         if (!process_is_command_handler()) { /* parent (server) */
 676                 mutex_destroy(mmd_mutex);
 677                 daemon_set_hooks(NULL, NULL); /* only one process remaining */
 678                 mutex_destroy(log_mutex);
 679                 deplete_close_on_fork_list();
 680                 if (ret < 0)
 681                         PARA_EMERG_LOG("%s\n", para_strerror(-ret));
 682                 vss_shutdown();
 683         } else {
 684                 vss_shutdown();
 685                 alarm(ALARM_TIMEOUT);
 686                 close_listed_fds();
 687                 ret = handle_connect(sct->child_fd);
 688         }
 689         shm_detach(mmd);
 690         user_list_deplete();
 691         free_lpr();
 692         exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);
 693 }