server.c

   1 /*
   2  * Copyright (C) 1997-2008 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file server.c Paraslash's main server. */
   8
   9
  10 /**
  11  * \mainpage Paraslash API Reference
  12  *
  13  * Starting points for getting an overview:
  14  *
  15  *      - The main programs: \ref server.c, \ref audiod.c, \ref client.c,
  16  *        \ref audioc.c, \ref fsck.c,
  17  *      - Server: \ref server_command, \ref sender,
  18  *      - Audio file selector: \ref audio_format_handler, \ref mood, \ref afs_table,
  19  *      - Client: \ref receiver, \ref receiver_node, \ref filter, \ref filter_node.
  20  *
  21  *
  22  * The gory details, listed by topic:
  23  *
  24  *      - Audio format handlers: \ref mp3_afh.c, \ref ogg_afh.c, \ref aac_afh.c,
  25  *      - Decoders: \ref mp3dec.c, \ref oggdec.c, \ref aacdec.c,
  26  *      - Volume normalizer: \ref compress.c,
  27  *      - Output: \ref alsa_write.c, \ref osx_write.c,
  28  *      - http: \ref http_recv.c, \ref http_send.c,
  29  *      - ortp: \ref ortp_recv.c, \ref ortp_send.c,
  30  *      - dccp: \ref dccp_recv.c, \ref dccp_send.c,
  31  *      - Audio file selector: \ref afs.c, \ref aft.c, \ref mood.c,
  32  *      - Afs structures: \ref afs_table, \ref audio_file_data,
  33  *        \ref afs_info \ref afh_info,
  34  *      - Afs tables: \ref aft.c, \ref mood.c, \ref playlist.c,
  35  *        \ref attribute.c, \ref score.c,
  36  *      - The virtual streaming system: \ref vss.c, \ref chunk_queue.c.
  37  *
  38  * Lower levels:
  39  *
  40  *      - Scheduling: \ref sched.c, \ref sched.h,
  41  *      - Networking: \ref net.c,
  42  *      - File descriptors: \ref fd.c,
  43  *      - Signals: \ref signal.c,
  44  *      - Daemons: \ref daemon.c,
  45  *      - Strings: \ref string.c, \ref string.h,
  46  *      - Time: \ref time.c,
  47  *      - Spawning processes: \ref exec.c,
  48  *      - Inter process communication: \ref ipc.c,
  49  *      - The object storage layer: \ref osl.c,
  50  *      - Blob tables: \ref blob.c,
  51  *      - The error subssystem: \ref error.h.
  52  *      - Access control for paraslash senders: \ref acl.c, \ref acl.h.
  53  *
  54  * Low-level data structures:
  55  *
  56  *      - Doubly linked lists: \ref list.h,
  57  *      - Red-black trees: \ref rbtree.h, \ref rbtree.c,
  58  *      - Ring buffer: \ref ringbuffer.c, \ref ringbuffer.h,
  59  *      - Hashing: \ref hash.h, \ref sha1.h, \ref sha1.c,
  60  *      - Crypto: \ref crypt.c.
  61  *
  62  */
  63
  64 #include <signal.h>
  65 #include <dirent.h>
  66
  67 #include "para.h"
  68 #include "error.h"
  69 #include "server.cmdline.h"
  70 #include "afh.h"
  71 #include "string.h"
  72 #include "afs.h"
  73 #include "server.h"
  74 #include "vss.h"
  75 #include "config.h"
  76 #include "close_on_fork.h"
  77 #include "list.h"
  78 #include "send.h"
  79 #include "net.h"
  80 #include "daemon.h"
  81 #include "ipc.h"
  82 #include "fd.h"
  83 #include "sched.h"
  84 #include "signal.h"
  85 #include "user_list.h"
  86
  87 /** Define the array of error lists needed by para_server. */
  88 INIT_SERVER_ERRLISTS;
  89
  90 /** Shut down non-authorized connections after that many seconds. */
  91 #define ALARM_TIMEOUT 10
  92
  93 /**
  94  * Pointer to shared memory area for communication between para_server
  95  * and its children. Exported to vss.c. command.c and to afs.
  96  */
  97 struct misc_meta_data *mmd;
  98
  99 /**
 100  * The configuration of para_server
 101  *
 102  * It also contains the options for the audio file selector, audio format
 103  * handler and all supported senders.
 104  */
 105 struct server_args_info conf;
 106
 107 /** A random value used in child context for authentication. */
 108 uint32_t afs_socket_cookie;
 109
 110 /* global variables for server-internal use */
 111 static FILE *logfile;
 112 /** The file containing user information (public key, permissions). */
 113 static char *user_list_file = NULL;
 114 static int mmd_mutex, mmd_shm_id;
 115 static pid_t afs_pid;
 116
 117
 118 /** The task resposible for server command handling. */
 119 struct server_command_task {
 120         /** TCP port on which para_server listens for connections. */
 121         int listen_fd;
 122         /** Copied from para_server's main function. */
 123         int argc;
 124         /** Argument vector passed to para_server's main function. */
 125         char **argv;
 126         /** The command task structure for scheduling. */
 127         struct task task;
 128 };
 129
 130 /**
 131  * Para_server's log function.
 132  *
 133  * \param ll The log level.
 134  * \param fmt The format string describing the log message.
 135  */
 136 void para_log(int ll, const char* fmt,...)
 137 {
 138         va_list argp;
 139         FILE *outfd;
 140         struct tm *tm;
 141         time_t t1;
 142         char str[MAXLINE] = "";
 143         pid_t mypid;
 144
 145         if (ll < conf.loglevel_arg)
 146                 return;
 147         outfd = logfile? logfile : stderr;
 148         time(&t1);
 149         tm = localtime(&t1);
 150         strftime(str, MAXLINE, "%b %d %H:%M:%S", tm);
 151         fprintf(outfd, "%s ", str);
 152         if (conf.loglevel_arg <= INFO)
 153                 fprintf(outfd, "%i: ", ll);
 154         mypid = getpid();
 155         if (conf.loglevel_arg <= INFO)
 156                 fprintf(outfd, "(%d) ", (int)mypid);
 157         va_start(argp, fmt);
 158         vfprintf(outfd, fmt, argp);
 159         va_end(argp);
 160 }
 161
 162 /*
 163  * setup shared memory area and get mutex for locking
 164  */
 165 static void shm_init(void)
 166 {
 167         void *shm;
 168         int ret = shm_new(sizeof(struct misc_meta_data));
 169
 170         if (ret < 0)
 171                 goto err_out;
 172
 173         ret = shm_attach(ret, ATTACH_RW, &shm);
 174         if (ret < 0)
 175                 goto err_out;
 176         mmd = shm;
 177         mmd_shm_id = ret;
 178
 179         ret = mutex_new();
 180         if (ret < 0)
 181                 goto err_out;
 182         mmd_mutex = ret;
 183
 184         mmd->num_played = 0;
 185         mmd->num_commands = 0;
 186         mmd->events = 0;
 187         mmd->num_connects = 0;
 188         mmd->active_connections = 0;
 189         mmd->vss_status_flags = VSS_NEXT;
 190         mmd->new_vss_status_flags = VSS_NEXT;
 191         return;
 192 err_out:
 193         PARA_EMERG_LOG("%s\n", para_strerror(-ret));
 194         exit(EXIT_FAILURE);
 195 }
 196
 197 /**
 198  * Lock the shared memory area containing the mmd struct.
 199  *
 200  * \sa semop(2), struct misc_meta_data.
 201  */
 202 void mmd_lock(void)
 203 {
 204         mutex_lock(mmd_mutex);
 205 }
 206
 207 /**
 208  * Unlock the shared memory area containing the mmd struct.
 209  *
 210  * \sa semop(2), struct misc_meta_data.
 211  */
 212
 213 void mmd_unlock(void)
 214 {
 215         mutex_unlock(mmd_mutex);
 216 }
 217
 218 static void parse_config(int override)
 219 {
 220         char *home = para_homedir();
 221         struct stat statbuf;
 222         int ret;
 223         char *cf;
 224
 225         if (conf.config_file_given)
 226                 cf = para_strdup(conf.config_file_arg);
 227         else
 228                 cf = make_message("%s/.paraslash/server.conf", home);
 229         free(user_list_file);
 230         if (!conf.user_list_given)
 231                 user_list_file = make_message("%s/.paraslash/server.users", home);
 232         else
 233                 user_list_file = para_strdup(conf.user_list_arg);
 234         ret = stat(cf, &statbuf);
 235         if (ret && conf.config_file_given) {
 236                 ret = -1;
 237                 PARA_EMERG_LOG("can not stat config file %s\n", cf);
 238                 goto out;
 239         }
 240         if (!ret) {
 241                 int tmp = conf.daemon_given;
 242                 struct server_cmdline_parser_params params = {
 243                         .override = override,
 244                         .initialize = 0,
 245                         .check_required = 1,
 246                         .check_ambiguity = 0,
 247                         .print_errors = 1
 248                 };
 249                 server_cmdline_parser_config_file(cf, &conf, &params);
 250                 conf.daemon_given = tmp;
 251         }
 252         if (conf.logfile_given)
 253                 logfile = open_log(conf.logfile_arg);
 254         ret = 1;
 255 out:
 256         free(cf);
 257         free(home);
 258         if (ret > 0)
 259                 return;
 260         free(user_list_file);
 261         user_list_file = NULL;
 262         exit(EXIT_FAILURE);
 263 }
 264
 265 static void signal_pre_select(struct sched *s, struct task *t)
 266 {
 267         struct signal_task *st = container_of(t, struct signal_task, task);
 268         para_fd_set(st->fd, &s->rfds, &s->max_fileno);
 269 }
 270
 271 /*
 272  * called when server gets SIGHUP or when client invokes hup command.
 273  */
 274 static void handle_sighup(void)
 275 {
 276         PARA_NOTICE_LOG("SIGHUP\n");
 277         close_log(logfile); /* gets reopened if necessary by parse_config */
 278         logfile = NULL;
 279         parse_config(1); /* reopens log */
 280         init_user_list(user_list_file); /* reload user list */
 281         if (afs_pid)
 282                 kill(afs_pid, SIGHUP);
 283 }
 284
 285 static void signal_post_select(struct sched *s, struct task *t)
 286 {
 287         struct signal_task *st = container_of(t, struct signal_task, task);
 288
 289         if (!FD_ISSET(st->fd, &s->rfds))
 290                 return;
 291
 292         st->signum = para_next_signal();
 293         switch (st->signum) {
 294         case SIGHUP:
 295                 handle_sighup();
 296                 break;
 297         case SIGCHLD:
 298                 for (;;) {
 299                         pid_t pid;
 300                         int ret = para_reap_child(&pid);
 301                         if (ret <= 0)
 302                                 break;
 303                         if (pid != afs_pid)
 304                                 continue;
 305                         PARA_EMERG_LOG("fatal: afs died\n");
 306                         goto genocide;
 307                 }
 308                 break;
 309         /* die on sigint/sigterm. Kill all children too. */
 310         case SIGINT:
 311         case SIGTERM:
 312                 PARA_EMERG_LOG("terminating on signal %d\n", st->signum);
 313 genocide:
 314                 kill(0, SIGTERM);
 315                 mutex_destroy(mmd_mutex);
 316                 shm_detach(mmd);
 317                 shm_destroy(mmd_shm_id);
 318
 319                 exit(EXIT_FAILURE);
 320         }
 321 }
 322
 323 static void init_signal_task(void)
 324 {
 325         static struct signal_task signal_task_struct,
 326                 *st = &signal_task_struct;
 327
 328         st->task.pre_select = signal_pre_select;
 329         st->task.post_select = signal_post_select;
 330         sprintf(st->task.status, "signal task");
 331
 332         st->fd = para_signal_init(); /* always successful */
 333
 334         PARA_NOTICE_LOG("setting up signal handlers\n");
 335         if (para_install_sighandler(SIGINT) < 0)
 336                 goto err;
 337         if (para_install_sighandler(SIGTERM) < 0)
 338                 goto err;
 339         if (para_install_sighandler(SIGHUP) < 0)
 340                 goto err;
 341         if (para_install_sighandler(SIGCHLD) < 0)
 342                 goto err;
 343         if (signal(SIGPIPE, SIG_IGN) == SIG_ERR)
 344                 goto err;
 345         if (signal(SIGUSR1, SIG_IGN) == SIG_ERR)
 346                 goto err;
 347         add_close_on_fork_list(st->fd);
 348         register_task(&st->task);
 349         return;
 350 err:
 351         PARA_EMERG_LOG("could not install signal handlers\n");
 352         exit(EXIT_FAILURE);
 353 }
 354
 355 static void command_pre_select(struct sched *s, struct task *t)
 356 {
 357         struct server_command_task *sct = container_of(t, struct server_command_task, task);
 358         para_fd_set(sct->listen_fd, &s->rfds, &s->max_fileno);
 359 }
 360
 361 static void command_post_select(struct sched *s, struct task *t)
 362 {
 363         struct server_command_task *sct = container_of(t, struct server_command_task, task);
 364
 365         int new_fd, ret, i;
 366         char *peer_name;
 367         pid_t child_pid;
 368
 369         if (!FD_ISSET(sct->listen_fd, &s->rfds))
 370                 return;
 371         ret = para_accept(sct->listen_fd, NULL, 0);
 372         if (ret < 0)
 373                 goto out;
 374         new_fd = ret;
 375         peer_name = remote_name(new_fd);
 376         PARA_INFO_LOG("got connection from %s, forking\n", peer_name);
 377         mmd->num_connects++;
 378         mmd->active_connections++;
 379         random();
 380         child_pid = fork();
 381         if (child_pid < 0) {
 382                 ret = -ERRNO_TO_PARA_ERROR(errno);
 383                 goto out;
 384         }
 385         if (child_pid) {
 386                 close(new_fd);
 387                 /* parent keeps accepting connections */
 388                 return;
 389         }
 390         alarm(ALARM_TIMEOUT);
 391         close_listed_fds();
 392         para_signal_shutdown();
 393         /*
 394          * put info on who we are serving into argv[0] to make
 395          * client ip visible in top/ps
 396          */
 397         for (i = sct->argc - 1; i >= 0; i--)
 398                 memset(sct->argv[i], 0, strlen(sct->argv[i]));
 399         sprintf(sct->argv[0], "para_server (serving %s)", peer_name);
 400         return handle_connect(new_fd, peer_name);
 401 out:
 402         if (ret < 0)
 403                 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
 404 }
 405
 406 static void init_server_command_task(int argc, char **argv)
 407 {
 408         int ret;
 409         static struct server_command_task server_command_task_struct,
 410                 *sct = &server_command_task_struct;
 411
 412         PARA_NOTICE_LOG("initializing tcp command socket\n");
 413         sct->task.pre_select = command_pre_select;
 414         sct->task.post_select = command_post_select;
 415         sct->argc = argc;
 416         sct->argv = argv;
 417         ret = para_listen(AF_UNSPEC, IPPROTO_TCP, conf.port_arg);
 418         if (ret < 0)
 419                 goto err;
 420         sct->listen_fd = ret;
 421         ret = mark_fd_nonblocking(sct->listen_fd);
 422         if (ret < 0)
 423                 goto err;
 424         add_close_on_fork_list(sct->listen_fd); /* child doesn't need the listener */
 425         register_task(&sct->task);
 426         return;
 427 err:
 428         PARA_EMERG_LOG("%s\n", para_strerror(-ret));
 429         exit(EXIT_FAILURE);
 430 }
 431
 432 static void init_random_seed(void)
 433 {
 434         unsigned int seed;
 435         int fd, ret = para_open("/dev/urandom", O_RDONLY, 0);
 436
 437         if (ret < 0)
 438                 goto err;
 439         fd = ret;
 440         ret = read(fd, &seed, sizeof(seed));
 441         if (ret < 0) {
 442                 ret = -ERRNO_TO_PARA_ERROR(errno);
 443                 goto out;
 444         }
 445         if (ret != sizeof(seed)) {
 446                 ret = -ERRNO_TO_PARA_ERROR(EIO);
 447                 goto out;
 448         }
 449         srandom(seed);
 450         ret = 1;
 451 out:
 452         close(fd);
 453         if (ret >= 0)
 454                 return;
 455 err:
 456         PARA_EMERG_LOG("can not seed pseudo random number generator: %s\n",
 457                 para_strerror(-ret));
 458         exit(EXIT_FAILURE);
 459 }
 460
 461 static int init_afs(void)
 462 {
 463         int ret, afs_server_socket[2];
 464
 465         ret = socketpair(PF_UNIX, SOCK_DGRAM, 0, afs_server_socket);
 466         if (ret < 0)
 467                 exit(EXIT_FAILURE);
 468         afs_socket_cookie = para_random((uint32_t)-1);
 469         afs_pid = fork();
 470         if (afs_pid < 0)
 471                 exit(EXIT_FAILURE);
 472         if (!afs_pid) { /* child (afs) */
 473                 close(afs_server_socket[0]);
 474                 afs_init(afs_socket_cookie, afs_server_socket[1]);
 475         }
 476         close(afs_server_socket[1]);
 477         ret = mark_fd_nonblocking(afs_server_socket[0]);
 478         if (ret < 0)
 479                 exit(EXIT_FAILURE);
 480         add_close_on_fork_list(afs_server_socket[0]);
 481         PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
 482                 afs_server_socket[0], (unsigned) afs_socket_cookie);
 483         return afs_server_socket[0];
 484 }
 485
 486 static void server_init(int argc, char **argv)
 487 {
 488         struct server_cmdline_parser_params params = {
 489                 .override = 0,
 490                 .initialize = 1,
 491                 .check_required = 0,
 492                 .check_ambiguity = 0,
 493                 .print_errors = 1
 494         };
 495         int afs_socket;
 496
 497         valid_fd_012();
 498         init_random_seed();
 499         /* parse command line options */
 500         server_cmdline_parser_ext(argc, argv, &conf, &params);
 501         HANDLE_VERSION_FLAG("server", conf);
 502         para_drop_privileges(conf.user_arg, conf.group_arg);
 503         /* parse config file, open log and set defaults */
 504         parse_config(0);
 505         log_welcome("para_server", conf.loglevel_arg);
 506         shm_init(); /* init mmd struct */
 507         server_uptime(UPTIME_SET); /* reset server uptime */
 508         init_user_list(user_list_file);
 509         /* become daemon */
 510         if (conf.daemon_given)
 511                 daemon_init();
 512         PARA_NOTICE_LOG("initializing audio format handlers\n");
 513         afh_init();
 514         mmd->server_pid = getpid();
 515         init_signal_task();
 516         PARA_NOTICE_LOG("initializing the audio file selector\n");
 517         afs_socket = init_afs();
 518         PARA_NOTICE_LOG("initializing virtual streaming system\n");
 519         init_vss_task(afs_socket);
 520         init_server_command_task(argc, argv);
 521         PARA_NOTICE_LOG("server init complete\n");
 522 }
 523
 524 static void status_refresh(void)
 525 {
 526         static int prev_uptime = -1, prev_events = -1;
 527         int uptime = server_uptime(UPTIME_GET), ret = 1;
 528
 529         if (prev_events != mmd->events)
 530                 goto out;
 531         if (mmd->new_vss_status_flags != mmd->vss_status_flags)
 532                 goto out_inc_events;
 533         if (uptime / 60 != prev_uptime / 60)
 534                 goto out_inc_events;
 535         return;
 536 out_inc_events:
 537         mmd->events++;
 538 out:
 539         prev_uptime = uptime;
 540         prev_events = mmd->events;
 541         mmd->vss_status_flags = mmd->new_vss_status_flags;
 542         if (ret) {
 543                 PARA_DEBUG_LOG("%d events, forcing status update\n",
 544                         mmd->events);
 545                 killpg(0, SIGUSR1);
 546         }
 547 }
 548
 549 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
 550                 struct timeval *timeout_tv)
 551 {
 552         int ret;
 553
 554         status_refresh();
 555         mmd_unlock();
 556         ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
 557         mmd_lock();
 558         return ret;
 559 }
 560
 561 /**
 562  * The main function of para_server.
 563  *
 564  * \param argc Usual argument count.
 565  * \param argv Usual argument vector.
 566  *
 567  * \return EXIT_SUCCESS or EXIT_FAILURE.
 568  */
 569 int main(int argc, char *argv[])
 570 {
 571         int ret;
 572         static struct sched s = {
 573                 .default_timeout = {
 574                         .tv_sec = 1,
 575                         .tv_usec = 0
 576                 },
 577                 .select_function = server_select
 578         };
 579         server_init(argc, argv);
 580         mmd_lock();
 581         ret = schedule(&s);
 582         if (ret < 0) {
 583                 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
 584                 exit(EXIT_FAILURE);
 585         }
 586         exit(EXIT_SUCCESS);
 587 }