server.c

   1 /*
   2  * Copyright (C) 1997-2009 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  *
  16  *      - The main programs: \ref server.c, \ref audiod.c, \ref client.c,
  17  *        \ref audioc.c, \ref fsck.c, \ref afh.c
  18  *      - Server: \ref server_command, \ref sender,
  19  *      - Audio file selector: \ref audio_format_handler, \ref mood, \ref afs_table,
  20  *      - Client: \ref receiver, \ref receiver_node, \ref filter, \ref filter_node.
  21  *
  22  *
  23  * The gory details, listed by topic:
  24  *
  25  *      - Audio format handlers: \ref send_common.c \ref mp3_afh.c, \ref ogg_afh.c, \ref aac_afh.c,
  26  *      - Decoders: \ref mp3dec_filter.c, \ref oggdec_filter.c, \ref aacdec_filter.c,
  27  *      - Volume normalizer: \ref compress_filter.c,
  28  *      - Output: \ref alsa_write.c, \ref osx_write.c,
  29  *      - http: \ref http_recv.c, \ref http_send.c,
  30  *      - udp: \ref udp_recv.c, \ref udp_send.c,
  31  *      - dccp: \ref dccp_recv.c, \ref dccp_send.c,
  32  *      - Audio file selector: \ref afs.c, \ref aft.c, \ref mood.c,
  33  *      - Afs structures: \ref afs_table, \ref audio_file_data,
  34  *        \ref afs_info \ref afh_info,
  35  *      - Afs tables: \ref aft.c, \ref mood.c, \ref playlist.c,
  36  *        \ref attribute.c, \ref score.c,
  37  *      - The virtual streaming system: \ref vss.c, \ref chunk_queue.c.
  38  *
  39  * Lower levels:
  40  *
  41  *      - Scheduling: \ref sched.c, \ref sched.h,
  42  *      - Networking: \ref net.c,
  43  *      - File descriptors: \ref fd.c,
  44  *      - Signals: \ref signal.c,
  45  *      - Daemons: \ref daemon.c,
  46  *      - Strings: \ref string.c, \ref string.h,
  47  *      - Time: \ref time.c,
  48  *      - Spawning processes: \ref exec.c,
  49  *      - Inter process communication: \ref ipc.c,
  50  *      - The object storage layer: \ref osl.c,
  51  *      - Blob tables: \ref blob.c,
  52  *      - The error subssystem: \ref error.h.
  53  *      - Access control for paraslash senders: \ref acl.c, \ref acl.h.
  54  *
  55  * Low-level data structures:
  56  *
  57  *      - Doubly linked lists: \ref list.h,
  58  *      - Red-black trees: \ref rbtree.h, \ref rbtree.c,
  59  *      - Ring buffer: \ref ringbuffer.c, \ref ringbuffer.h,
  60  *      - Hashing: \ref hash.h, \ref sha1.h, \ref sha1.c,
  61  *      - Crypto: \ref crypt.c.
  62  *
  63  */
  64
  65 #include <signal.h>
  66 #include <dirent.h>
  67 #include <sys/time.h>
  68
  69 #include "para.h"
  70 #include "error.h"
  71 #include "server.cmdline.h"
  72 #include "afh.h"
  73 #include "string.h"
  74 #include "afs.h"
  75 #include "server.h"
  76 #include "vss.h"
  77 #include "config.h"
  78 #include "close_on_fork.h"
  79 #include "list.h"
  80 #include "send.h"
  81 #include "net.h"
  82 #include "daemon.h"
  83 #include "ipc.h"
  84 #include "fd.h"
  85 #include "sched.h"
  86 #include "signal.h"
  87 #include "user_list.h"
  88
  89 /** Define the array of error lists needed by para_server. */
  90 INIT_SERVER_ERRLISTS;
  91
  92 /** Shut down non-authorized connections after that many seconds. */
  93 #define ALARM_TIMEOUT 10
  94
  95 /**
  96  * Pointer to shared memory area for communication between para_server
  97  * and its children. Exported to vss.c. command.c and to afs.
  98  */
  99 struct misc_meta_data *mmd;
 100
 101 /**
 102  * The configuration of para_server
 103  *
 104  * It also contains the options for the audio file selector, audio format
 105  * handler and all supported senders.
 106  */
 107 struct server_args_info conf;
 108
 109 /** A random value used in child context for authentication. */
 110 uint32_t afs_socket_cookie;
 111
 112 /** The mutex protecting the shared memory area containing the mmd struct. */
 113 int mmd_mutex;
 114
 115 /* global variables for server-internal use */
 116 static FILE *logfile;
 117 /** The file containing user information (public key, permissions). */
 118 static char *user_list_file = NULL;
 119 static int mmd_shm_id;
 120
 121
 122 /** The task responsible for server command handling. */
 123 struct server_command_task {
 124         /** TCP port on which para_server listens for connections. */
 125         int listen_fd;
 126         /** Copied from para_server's main function. */
 127         int argc;
 128         /** Argument vector passed to para_server's main function. */
 129         char **argv;
 130         /** The command task structure for scheduling. */
 131         struct task task;
 132 };
 133
 134 /**
 135  * Para_server's log function.
 136  *
 137  * \param ll The log level.
 138  * \param fmt The format string describing the log message.
 139  */
 140 __printf_2_3 void para_log(int ll, const char* fmt,...)
 141 {
 142         va_list argp;
 143         FILE *outfd;
 144         struct tm *tm;
 145         time_t t1;
 146         char str[MAXLINE] = "";
 147         pid_t mypid;
 148
 149         if (ll < conf.loglevel_arg)
 150                 return;
 151         outfd = logfile? logfile : stderr;
 152         time(&t1);
 153         tm = localtime(&t1);
 154         strftime(str, MAXLINE, "%b %d %H:%M:%S", tm);
 155         fprintf(outfd, "%s ", str);
 156         if (conf.loglevel_arg <= INFO)
 157                 fprintf(outfd, "%i: ", ll);
 158         mypid = getpid();
 159         if (conf.loglevel_arg <= INFO)
 160                 fprintf(outfd, "(%d) ", (int)mypid);
 161         va_start(argp, fmt);
 162         vfprintf(outfd, fmt, argp);
 163         va_end(argp);
 164 }
 165
 166 /*
 167  * setup shared memory area and get mutex for locking
 168  */
 169 static void init_ipc_or_die(void)
 170 {
 171         void *shm;
 172         int ret = shm_new(sizeof(struct misc_meta_data));
 173
 174         if (ret < 0)
 175                 goto err_out;
 176
 177         ret = shm_attach(ret, ATTACH_RW, &shm);
 178         if (ret < 0)
 179                 goto err_out;
 180         mmd = shm;
 181         mmd_shm_id = ret;
 182
 183         ret = mutex_new();
 184         if (ret < 0)
 185                 goto err_out;
 186         mmd_mutex = ret;
 187
 188         mmd->num_played = 0;
 189         mmd->num_commands = 0;
 190         mmd->events = 0;
 191         mmd->num_connects = 0;
 192         mmd->active_connections = 0;
 193         mmd->vss_status_flags = VSS_NEXT;
 194         mmd->new_vss_status_flags = VSS_NEXT;
 195         return;
 196 err_out:
 197         PARA_EMERG_LOG("%s\n", para_strerror(-ret));
 198         exit(EXIT_FAILURE);
 199 }
 200
 201 /**
 202  * (Re-)read the server configuration files.
 203  *
 204  * \param override Passed to gengetopt to activate the override feature.
 205  *
 206  * This function also re-opens the logfile and sets the global \a
 207  * user_list_file variable.
 208  */
 209 void parse_config_or_die(int override)
 210 {
 211         char *home = para_homedir();
 212         struct stat statbuf;
 213         int ret;
 214         char *cf;
 215
 216         close_log(logfile);
 217         logfile = NULL;
 218         if (conf.config_file_given)
 219                 cf = para_strdup(conf.config_file_arg);
 220         else
 221                 cf = make_message("%s/.paraslash/server.conf", home);
 222         free(user_list_file);
 223         if (!conf.user_list_given)
 224                 user_list_file = make_message("%s/.paraslash/server.users", home);
 225         else
 226                 user_list_file = para_strdup(conf.user_list_arg);
 227         ret = stat(cf, &statbuf);
 228         if (ret && conf.config_file_given) {
 229                 ret = -1;
 230                 PARA_EMERG_LOG("can not stat config file %s\n", cf);
 231                 goto out;
 232         }
 233         if (!ret) {
 234                 int tmp = conf.daemon_given;
 235                 struct server_cmdline_parser_params params = {
 236                         .override = override,
 237                         .initialize = 0,
 238                         .check_required = 1,
 239                         .check_ambiguity = 0,
 240                         .print_errors = 1
 241                 };
 242                 server_cmdline_parser_config_file(cf, &conf, &params);
 243                 conf.daemon_given = tmp;
 244         }
 245         if (conf.logfile_given)
 246                 logfile = open_log(conf.logfile_arg);
 247         ret = 1;
 248 out:
 249         free(cf);
 250         free(home);
 251         if (ret > 0)
 252                 return;
 253         free(user_list_file);
 254         user_list_file = NULL;
 255         exit(EXIT_FAILURE);
 256 }
 257
 258 static void signal_pre_select(struct sched *s, struct task *t)
 259 {
 260         struct signal_task *st = container_of(t, struct signal_task, task);
 261         para_fd_set(st->fd, &s->rfds, &s->max_fileno);
 262 }
 263
 264 /*
 265  * called when server gets SIGHUP or when client invokes hup command.
 266  */
 267 static void handle_sighup(void)
 268 {
 269         PARA_NOTICE_LOG("SIGHUP\n");
 270         parse_config_or_die(1); /* reopens log */
 271         init_user_list(user_list_file); /* reload user list */
 272         if (mmd->afs_pid)
 273                 kill(mmd->afs_pid, SIGHUP);
 274 }
 275
 276 static void signal_post_select(struct sched *s, struct task *t)
 277 {
 278         struct signal_task *st = container_of(t, struct signal_task, task);
 279
 280         if (!FD_ISSET(st->fd, &s->rfds))
 281                 return;
 282
 283         st->signum = para_next_signal();
 284         switch (st->signum) {
 285         case SIGHUP:
 286                 handle_sighup();
 287                 break;
 288         case SIGCHLD:
 289                 for (;;) {
 290                         pid_t pid;
 291                         int ret = para_reap_child(&pid);
 292                         if (ret <= 0)
 293                                 break;
 294                         if (pid != mmd->afs_pid)
 295                                 continue;
 296                         PARA_EMERG_LOG("fatal: afs died\n");
 297                         goto genocide;
 298                 }
 299                 break;
 300         /* die on sigint/sigterm. Kill all children too. */
 301         case SIGINT:
 302         case SIGTERM:
 303                 PARA_EMERG_LOG("terminating on signal %d\n", st->signum);
 304 genocide:
 305                 kill(0, SIGTERM);
 306                 mutex_destroy(mmd_mutex);
 307                 shm_detach(mmd);
 308                 shm_destroy(mmd_shm_id);
 309
 310                 exit(EXIT_FAILURE);
 311         }
 312 }
 313
 314 static void init_signal_task(void)
 315 {
 316         static struct signal_task signal_task_struct,
 317                 *st = &signal_task_struct;
 318
 319         st->task.pre_select = signal_pre_select;
 320         st->task.post_select = signal_post_select;
 321         sprintf(st->task.status, "signal task");
 322
 323         st->fd = para_signal_init(); /* always successful */
 324
 325         PARA_NOTICE_LOG("setting up signal handlers\n");
 326         if (para_install_sighandler(SIGINT) < 0)
 327                 goto err;
 328         if (para_install_sighandler(SIGTERM) < 0)
 329                 goto err;
 330         if (para_install_sighandler(SIGHUP) < 0)
 331                 goto err;
 332         if (para_install_sighandler(SIGCHLD) < 0)
 333                 goto err;
 334         if (signal(SIGPIPE, SIG_IGN) == SIG_ERR)
 335                 goto err;
 336         if (signal(SIGUSR1, SIG_IGN) == SIG_ERR)
 337                 goto err;
 338         add_close_on_fork_list(st->fd);
 339         register_task(&st->task);
 340         return;
 341 err:
 342         PARA_EMERG_LOG("could not install signal handlers\n");
 343         exit(EXIT_FAILURE);
 344 }
 345
 346 static void command_pre_select(struct sched *s, struct task *t)
 347 {
 348         struct server_command_task *sct = container_of(t, struct server_command_task, task);
 349         para_fd_set(sct->listen_fd, &s->rfds, &s->max_fileno);
 350 }
 351
 352 static void command_post_select(struct sched *s, struct task *t)
 353 {
 354         struct server_command_task *sct = container_of(t, struct server_command_task, task);
 355
 356         int new_fd, ret, i;
 357         char *peer_name;
 358         pid_t child_pid;
 359
 360         if (!FD_ISSET(sct->listen_fd, &s->rfds))
 361                 return;
 362         ret = para_accept(sct->listen_fd, NULL, 0);
 363         if (ret < 0)
 364                 goto out;
 365         new_fd = ret;
 366         peer_name = remote_name(new_fd);
 367         PARA_INFO_LOG("got connection from %s, forking\n", peer_name);
 368         mmd->num_connects++;
 369         mmd->active_connections++;
 370         random();
 371         child_pid = fork();
 372         if (child_pid < 0) {
 373                 ret = -ERRNO_TO_PARA_ERROR(errno);
 374                 goto out;
 375         }
 376         if (child_pid) {
 377                 close(new_fd);
 378                 /* parent keeps accepting connections */
 379                 return;
 380         }
 381         alarm(ALARM_TIMEOUT);
 382         close_listed_fds();
 383         para_signal_shutdown();
 384         /*
 385          * put info on who we are serving into argv[0] to make
 386          * client ip visible in top/ps
 387          */
 388         for (i = sct->argc - 1; i >= 0; i--)
 389                 memset(sct->argv[i], 0, strlen(sct->argv[i]));
 390         sprintf(sct->argv[0], "para_server (serving %s)", peer_name);
 391         return handle_connect(new_fd, peer_name);
 392 out:
 393         if (ret < 0)
 394                 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
 395 }
 396
 397 static void init_server_command_task(int argc, char **argv)
 398 {
 399         int ret;
 400         static struct server_command_task server_command_task_struct,
 401                 *sct = &server_command_task_struct;
 402
 403         PARA_NOTICE_LOG("initializing tcp command socket\n");
 404         sct->task.pre_select = command_pre_select;
 405         sct->task.post_select = command_post_select;
 406         sct->argc = argc;
 407         sct->argv = argv;
 408         ret = para_listen(AF_UNSPEC, IPPROTO_TCP, conf.port_arg);
 409         if (ret < 0)
 410                 goto err;
 411         sct->listen_fd = ret;
 412         ret = mark_fd_nonblocking(sct->listen_fd);
 413         if (ret < 0)
 414                 goto err;
 415         add_close_on_fork_list(sct->listen_fd); /* child doesn't need the listener */
 416         register_task(&sct->task);
 417         return;
 418 err:
 419         PARA_EMERG_LOG("%s\n", para_strerror(-ret));
 420         exit(EXIT_FAILURE);
 421 }
 422
 423 static void init_random_seed(void)
 424 {
 425         unsigned int seed;
 426         int fd, ret = para_open("/dev/urandom", O_RDONLY, 0);
 427
 428         if (ret < 0)
 429                 goto err;
 430         fd = ret;
 431         ret = read(fd, &seed, sizeof(seed));
 432         if (ret < 0) {
 433                 ret = -ERRNO_TO_PARA_ERROR(errno);
 434                 goto out;
 435         }
 436         if (ret != sizeof(seed)) {
 437                 ret = -ERRNO_TO_PARA_ERROR(EIO);
 438                 goto out;
 439         }
 440         srandom(seed);
 441         ret = 1;
 442 out:
 443         close(fd);
 444         if (ret >= 0)
 445                 return;
 446 err:
 447         PARA_EMERG_LOG("can not seed pseudo random number generator: %s\n",
 448                 para_strerror(-ret));
 449         exit(EXIT_FAILURE);
 450 }
 451
 452 static int init_afs(void)
 453 {
 454         int ret, afs_server_socket[2];
 455
 456         ret = socketpair(PF_UNIX, SOCK_DGRAM, 0, afs_server_socket);
 457         if (ret < 0)
 458                 exit(EXIT_FAILURE);
 459         afs_socket_cookie = para_random((uint32_t)-1);
 460         mmd->afs_pid = fork();
 461         if (mmd->afs_pid < 0)
 462                 exit(EXIT_FAILURE);
 463         if (!mmd->afs_pid) { /* child (afs) */
 464                 close(afs_server_socket[0]);
 465                 afs_init(afs_socket_cookie, afs_server_socket[1]);
 466         }
 467         close(afs_server_socket[1]);
 468         ret = mark_fd_nonblocking(afs_server_socket[0]);
 469         if (ret < 0)
 470                 exit(EXIT_FAILURE);
 471         add_close_on_fork_list(afs_server_socket[0]);
 472         PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
 473                 afs_server_socket[0], (unsigned) afs_socket_cookie);
 474         return afs_server_socket[0];
 475 }
 476
 477 static void server_init(int argc, char **argv)
 478 {
 479         struct server_cmdline_parser_params params = {
 480                 .override = 0,
 481                 .initialize = 1,
 482                 .check_required = 0,
 483                 .check_ambiguity = 0,
 484                 .print_errors = 1
 485         };
 486         int afs_socket;
 487
 488         valid_fd_012();
 489         init_random_seed();
 490         /* parse command line options */
 491         server_cmdline_parser_ext(argc, argv, &conf, &params);
 492         HANDLE_VERSION_FLAG("server", conf);
 493         drop_privileges_or_die(conf.user_arg, conf.group_arg);
 494         /* parse config file, open log and set defaults */
 495         parse_config_or_die(0);
 496         log_welcome("para_server", conf.loglevel_arg);
 497         init_ipc_or_die(); /* init mmd struct and mmd->lock */
 498         /* make sure, the global now pointer is uptodate */
 499         gettimeofday(now, NULL);
 500         server_uptime(UPTIME_SET); /* reset server uptime */
 501         init_user_list(user_list_file);
 502         /* become daemon */
 503         if (conf.daemon_given)
 504                 daemon_init();
 505         PARA_NOTICE_LOG("initializing audio format handlers\n");
 506         afh_init();
 507         PARA_NOTICE_LOG("initializing the audio file selector\n");
 508         afs_socket = init_afs();
 509         init_signal_task();
 510         PARA_NOTICE_LOG("initializing virtual streaming system\n");
 511         init_vss_task(afs_socket);
 512         init_server_command_task(argc, argv);
 513         PARA_NOTICE_LOG("server init complete\n");
 514 }
 515
 516 static void status_refresh(void)
 517 {
 518         static int prev_uptime = -1, prev_events = -1;
 519         int uptime = server_uptime(UPTIME_GET), ret = 1;
 520
 521         if (prev_events != mmd->events)
 522                 goto out;
 523         if (mmd->new_vss_status_flags != mmd->vss_status_flags)
 524                 goto out_inc_events;
 525         if (uptime / 60 != prev_uptime / 60)
 526                 goto out_inc_events;
 527         return;
 528 out_inc_events:
 529         mmd->events++;
 530 out:
 531         prev_uptime = uptime;
 532         prev_events = mmd->events;
 533         mmd->vss_status_flags = mmd->new_vss_status_flags;
 534         if (ret) {
 535                 PARA_DEBUG_LOG("%d events, forcing status update\n",
 536                         mmd->events);
 537                 killpg(0, SIGUSR1);
 538         }
 539 }
 540
 541 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
 542                 struct timeval *timeout_tv)
 543 {
 544         int ret;
 545
 546         status_refresh();
 547         mutex_unlock(mmd_mutex);
 548         ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
 549         mutex_lock(mmd_mutex);
 550         return ret;
 551 }
 552
 553 /**
 554  * The main function of para_server.
 555  *
 556  * \param argc Usual argument count.
 557  * \param argv Usual argument vector.
 558  *
 559  * \return EXIT_SUCCESS or EXIT_FAILURE.
 560  */
 561 int main(int argc, char *argv[])
 562 {
 563         int ret;
 564         static struct sched s = {
 565                 .default_timeout = {
 566                         .tv_sec = 1,
 567                         .tv_usec = 0
 568                 },
 569                 .select_function = server_select
 570         };
 571         server_init(argc, argv);
 572         mutex_lock(mmd_mutex);
 573         ret = schedule(&s);
 574         if (ret < 0) {
 575                 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
 576                 exit(EXIT_FAILURE);
 577         }
 578         exit(EXIT_SUCCESS);
 579 }