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 /** The mutex protecting the shared memory area containing the mmd struct. */
 111 int mmd_mutex;
 112
 113 /* global variables for server-internal use */
 114 static FILE *logfile;
 115 /** The file containing user information (public key, permissions). */
 116 static char *user_list_file = NULL;
 117 static int mmd_shm_id;
 118
 119
 120 /** The task responsible for server command handling. */
 121 struct server_command_task {
 122         /** TCP port on which para_server listens for connections. */
 123         int listen_fd;
 124         /** Copied from para_server's main function. */
 125         int argc;
 126         /** Argument vector passed to para_server's main function. */
 127         char **argv;
 128         /** The command task structure for scheduling. */
 129         struct task task;
 130 };
 131
 132 /**
 133  * Para_server's log function.
 134  *
 135  * \param ll The log level.
 136  * \param fmt The format string describing the log message.
 137  */
 138 void para_log(int ll, const char* fmt,...)
 139 {
 140         va_list argp;
 141         FILE *outfd;
 142         struct tm *tm;
 143         time_t t1;
 144         char str[MAXLINE] = "";
 145         pid_t mypid;
 146
 147         if (ll < conf.loglevel_arg)
 148                 return;
 149         outfd = logfile? logfile : stderr;
 150         time(&t1);
 151         tm = localtime(&t1);
 152         strftime(str, MAXLINE, "%b %d %H:%M:%S", tm);
 153         fprintf(outfd, "%s ", str);
 154         if (conf.loglevel_arg <= INFO)
 155                 fprintf(outfd, "%i: ", ll);
 156         mypid = getpid();
 157         if (conf.loglevel_arg <= INFO)
 158                 fprintf(outfd, "(%d) ", (int)mypid);
 159         va_start(argp, fmt);
 160         vfprintf(outfd, fmt, argp);
 161         va_end(argp);
 162 }
 163
 164 /*
 165  * setup shared memory area and get mutex for locking
 166  */
 167 static void shm_init(void)
 168 {
 169         void *shm;
 170         int ret = shm_new(sizeof(struct misc_meta_data));
 171
 172         if (ret < 0)
 173                 goto err_out;
 174
 175         ret = shm_attach(ret, ATTACH_RW, &shm);
 176         if (ret < 0)
 177                 goto err_out;
 178         mmd = shm;
 179         mmd_shm_id = ret;
 180
 181         ret = mutex_new();
 182         if (ret < 0)
 183                 goto err_out;
 184         mmd_mutex = ret;
 185
 186         mmd->num_played = 0;
 187         mmd->num_commands = 0;
 188         mmd->events = 0;
 189         mmd->num_connects = 0;
 190         mmd->active_connections = 0;
 191         mmd->vss_status_flags = VSS_NEXT;
 192         mmd->new_vss_status_flags = VSS_NEXT;
 193         return;
 194 err_out:
 195         PARA_EMERG_LOG("%s\n", para_strerror(-ret));
 196         exit(EXIT_FAILURE);
 197 }
 198
 199 static void parse_config(int override)
 200 {
 201         char *home = para_homedir();
 202         struct stat statbuf;
 203         int ret;
 204         char *cf;
 205
 206         if (conf.config_file_given)
 207                 cf = para_strdup(conf.config_file_arg);
 208         else
 209                 cf = make_message("%s/.paraslash/server.conf", home);
 210         free(user_list_file);
 211         if (!conf.user_list_given)
 212                 user_list_file = make_message("%s/.paraslash/server.users", home);
 213         else
 214                 user_list_file = para_strdup(conf.user_list_arg);
 215         ret = stat(cf, &statbuf);
 216         if (ret && conf.config_file_given) {
 217                 ret = -1;
 218                 PARA_EMERG_LOG("can not stat config file %s\n", cf);
 219                 goto out;
 220         }
 221         if (!ret) {
 222                 int tmp = conf.daemon_given;
 223                 struct server_cmdline_parser_params params = {
 224                         .override = override,
 225                         .initialize = 0,
 226                         .check_required = 1,
 227                         .check_ambiguity = 0,
 228                         .print_errors = 1
 229                 };
 230                 server_cmdline_parser_config_file(cf, &conf, &params);
 231                 conf.daemon_given = tmp;
 232         }
 233         if (conf.logfile_given)
 234                 logfile = open_log(conf.logfile_arg);
 235         ret = 1;
 236 out:
 237         free(cf);
 238         free(home);
 239         if (ret > 0)
 240                 return;
 241         free(user_list_file);
 242         user_list_file = NULL;
 243         exit(EXIT_FAILURE);
 244 }
 245
 246 static void signal_pre_select(struct sched *s, struct task *t)
 247 {
 248         struct signal_task *st = container_of(t, struct signal_task, task);
 249         para_fd_set(st->fd, &s->rfds, &s->max_fileno);
 250 }
 251
 252 /*
 253  * called when server gets SIGHUP or when client invokes hup command.
 254  */
 255 static void handle_sighup(void)
 256 {
 257         PARA_NOTICE_LOG("SIGHUP\n");
 258         close_log(logfile); /* gets reopened if necessary by parse_config */
 259         logfile = NULL;
 260         parse_config(1); /* reopens log */
 261         init_user_list(user_list_file); /* reload user list */
 262         if (mmd->afs_pid)
 263                 kill(mmd->afs_pid, SIGHUP);
 264 }
 265
 266 static void signal_post_select(struct sched *s, struct task *t)
 267 {
 268         struct signal_task *st = container_of(t, struct signal_task, task);
 269
 270         if (!FD_ISSET(st->fd, &s->rfds))
 271                 return;
 272
 273         st->signum = para_next_signal();
 274         switch (st->signum) {
 275         case SIGHUP:
 276                 handle_sighup();
 277                 break;
 278         case SIGCHLD:
 279                 for (;;) {
 280                         pid_t pid;
 281                         int ret = para_reap_child(&pid);
 282                         if (ret <= 0)
 283                                 break;
 284                         if (pid != mmd->afs_pid)
 285                                 continue;
 286                         PARA_EMERG_LOG("fatal: afs died\n");
 287                         goto genocide;
 288                 }
 289                 break;
 290         /* die on sigint/sigterm. Kill all children too. */
 291         case SIGINT:
 292         case SIGTERM:
 293                 PARA_EMERG_LOG("terminating on signal %d\n", st->signum);
 294 genocide:
 295                 kill(0, SIGTERM);
 296                 mutex_destroy(mmd_mutex);
 297                 shm_detach(mmd);
 298                 shm_destroy(mmd_shm_id);
 299
 300                 exit(EXIT_FAILURE);
 301         }
 302 }
 303
 304 static void init_signal_task(void)
 305 {
 306         static struct signal_task signal_task_struct,
 307                 *st = &signal_task_struct;
 308
 309         st->task.pre_select = signal_pre_select;
 310         st->task.post_select = signal_post_select;
 311         sprintf(st->task.status, "signal task");
 312
 313         st->fd = para_signal_init(); /* always successful */
 314
 315         PARA_NOTICE_LOG("setting up signal handlers\n");
 316         if (para_install_sighandler(SIGINT) < 0)
 317                 goto err;
 318         if (para_install_sighandler(SIGTERM) < 0)
 319                 goto err;
 320         if (para_install_sighandler(SIGHUP) < 0)
 321                 goto err;
 322         if (para_install_sighandler(SIGCHLD) < 0)
 323                 goto err;
 324         if (signal(SIGPIPE, SIG_IGN) == SIG_ERR)
 325                 goto err;
 326         if (signal(SIGUSR1, SIG_IGN) == SIG_ERR)
 327                 goto err;
 328         add_close_on_fork_list(st->fd);
 329         register_task(&st->task);
 330         return;
 331 err:
 332         PARA_EMERG_LOG("could not install signal handlers\n");
 333         exit(EXIT_FAILURE);
 334 }
 335
 336 static void command_pre_select(struct sched *s, struct task *t)
 337 {
 338         struct server_command_task *sct = container_of(t, struct server_command_task, task);
 339         para_fd_set(sct->listen_fd, &s->rfds, &s->max_fileno);
 340 }
 341
 342 static void command_post_select(struct sched *s, struct task *t)
 343 {
 344         struct server_command_task *sct = container_of(t, struct server_command_task, task);
 345
 346         int new_fd, ret, i;
 347         char *peer_name;
 348         pid_t child_pid;
 349
 350         if (!FD_ISSET(sct->listen_fd, &s->rfds))
 351                 return;
 352         ret = para_accept(sct->listen_fd, NULL, 0);
 353         if (ret < 0)
 354                 goto out;
 355         new_fd = ret;
 356         peer_name = remote_name(new_fd);
 357         PARA_INFO_LOG("got connection from %s, forking\n", peer_name);
 358         mmd->num_connects++;
 359         mmd->active_connections++;
 360         random();
 361         child_pid = fork();
 362         if (child_pid < 0) {
 363                 ret = -ERRNO_TO_PARA_ERROR(errno);
 364                 goto out;
 365         }
 366         if (child_pid) {
 367                 close(new_fd);
 368                 /* parent keeps accepting connections */
 369                 return;
 370         }
 371         alarm(ALARM_TIMEOUT);
 372         close_listed_fds();
 373         para_signal_shutdown();
 374         /*
 375          * put info on who we are serving into argv[0] to make
 376          * client ip visible in top/ps
 377          */
 378         for (i = sct->argc - 1; i >= 0; i--)
 379                 memset(sct->argv[i], 0, strlen(sct->argv[i]));
 380         sprintf(sct->argv[0], "para_server (serving %s)", peer_name);
 381         return handle_connect(new_fd, peer_name);
 382 out:
 383         if (ret < 0)
 384                 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
 385 }
 386
 387 static void init_server_command_task(int argc, char **argv)
 388 {
 389         int ret;
 390         static struct server_command_task server_command_task_struct,
 391                 *sct = &server_command_task_struct;
 392
 393         PARA_NOTICE_LOG("initializing tcp command socket\n");
 394         sct->task.pre_select = command_pre_select;
 395         sct->task.post_select = command_post_select;
 396         sct->argc = argc;
 397         sct->argv = argv;
 398         ret = para_listen(AF_UNSPEC, IPPROTO_TCP, conf.port_arg);
 399         if (ret < 0)
 400                 goto err;
 401         sct->listen_fd = ret;
 402         ret = mark_fd_nonblocking(sct->listen_fd);
 403         if (ret < 0)
 404                 goto err;
 405         add_close_on_fork_list(sct->listen_fd); /* child doesn't need the listener */
 406         register_task(&sct->task);
 407         return;
 408 err:
 409         PARA_EMERG_LOG("%s\n", para_strerror(-ret));
 410         exit(EXIT_FAILURE);
 411 }
 412
 413 static void init_random_seed(void)
 414 {
 415         unsigned int seed;
 416         int fd, ret = para_open("/dev/urandom", O_RDONLY, 0);
 417
 418         if (ret < 0)
 419                 goto err;
 420         fd = ret;
 421         ret = read(fd, &seed, sizeof(seed));
 422         if (ret < 0) {
 423                 ret = -ERRNO_TO_PARA_ERROR(errno);
 424                 goto out;
 425         }
 426         if (ret != sizeof(seed)) {
 427                 ret = -ERRNO_TO_PARA_ERROR(EIO);
 428                 goto out;
 429         }
 430         srandom(seed);
 431         ret = 1;
 432 out:
 433         close(fd);
 434         if (ret >= 0)
 435                 return;
 436 err:
 437         PARA_EMERG_LOG("can not seed pseudo random number generator: %s\n",
 438                 para_strerror(-ret));
 439         exit(EXIT_FAILURE);
 440 }
 441
 442 static int init_afs(void)
 443 {
 444         int ret, afs_server_socket[2];
 445
 446         ret = socketpair(PF_UNIX, SOCK_DGRAM, 0, afs_server_socket);
 447         if (ret < 0)
 448                 exit(EXIT_FAILURE);
 449         afs_socket_cookie = para_random((uint32_t)-1);
 450         mmd->afs_pid = fork();
 451         if (mmd->afs_pid < 0)
 452                 exit(EXIT_FAILURE);
 453         if (!mmd->afs_pid) { /* child (afs) */
 454                 close(afs_server_socket[0]);
 455                 afs_init(afs_socket_cookie, afs_server_socket[1]);
 456         }
 457         close(afs_server_socket[1]);
 458         ret = mark_fd_nonblocking(afs_server_socket[0]);
 459         if (ret < 0)
 460                 exit(EXIT_FAILURE);
 461         add_close_on_fork_list(afs_server_socket[0]);
 462         PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
 463                 afs_server_socket[0], (unsigned) afs_socket_cookie);
 464         return afs_server_socket[0];
 465 }
 466
 467 static void server_init(int argc, char **argv)
 468 {
 469         struct server_cmdline_parser_params params = {
 470                 .override = 0,
 471                 .initialize = 1,
 472                 .check_required = 0,
 473                 .check_ambiguity = 0,
 474                 .print_errors = 1
 475         };
 476         int afs_socket;
 477
 478         valid_fd_012();
 479         init_random_seed();
 480         /* parse command line options */
 481         server_cmdline_parser_ext(argc, argv, &conf, &params);
 482         HANDLE_VERSION_FLAG("server", conf);
 483         para_drop_privileges(conf.user_arg, conf.group_arg);
 484         /* parse config file, open log and set defaults */
 485         parse_config(0);
 486         log_welcome("para_server", conf.loglevel_arg);
 487         shm_init(); /* init mmd struct */
 488         server_uptime(UPTIME_SET); /* reset server uptime */
 489         init_user_list(user_list_file);
 490         /* become daemon */
 491         if (conf.daemon_given)
 492                 daemon_init();
 493         PARA_NOTICE_LOG("initializing audio format handlers\n");
 494         afh_init();
 495         init_signal_task();
 496         PARA_NOTICE_LOG("initializing the audio file selector\n");
 497         afs_socket = init_afs();
 498         PARA_NOTICE_LOG("initializing virtual streaming system\n");
 499         init_vss_task(afs_socket);
 500         init_server_command_task(argc, argv);
 501         PARA_NOTICE_LOG("server init complete\n");
 502 }
 503
 504 static void status_refresh(void)
 505 {
 506         static int prev_uptime = -1, prev_events = -1;
 507         int uptime = server_uptime(UPTIME_GET), ret = 1;
 508
 509         if (prev_events != mmd->events)
 510                 goto out;
 511         if (mmd->new_vss_status_flags != mmd->vss_status_flags)
 512                 goto out_inc_events;
 513         if (uptime / 60 != prev_uptime / 60)
 514                 goto out_inc_events;
 515         return;
 516 out_inc_events:
 517         mmd->events++;
 518 out:
 519         prev_uptime = uptime;
 520         prev_events = mmd->events;
 521         mmd->vss_status_flags = mmd->new_vss_status_flags;
 522         if (ret) {
 523                 PARA_DEBUG_LOG("%d events, forcing status update\n",
 524                         mmd->events);
 525                 killpg(0, SIGUSR1);
 526         }
 527 }
 528
 529 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
 530                 struct timeval *timeout_tv)
 531 {
 532         int ret;
 533
 534         status_refresh();
 535         mutex_unlock(mmd_mutex);
 536         ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
 537         mutex_lock(mmd_mutex);
 538         return ret;
 539 }
 540
 541 /**
 542  * The main function of para_server.
 543  *
 544  * \param argc Usual argument count.
 545  * \param argv Usual argument vector.
 546  *
 547  * \return EXIT_SUCCESS or EXIT_FAILURE.
 548  */
 549 int main(int argc, char *argv[])
 550 {
 551         int ret;
 552         static struct sched s = {
 553                 .default_timeout = {
 554                         .tv_sec = 1,
 555                         .tv_usec = 0
 556                 },
 557                 .select_function = server_select
 558         };
 559         server_init(argc, argv);
 560         mutex_lock(mmd_mutex);
 561         ret = schedule(&s);
 562         if (ret < 0) {
 563                 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
 564                 exit(EXIT_FAILURE);
 565         }
 566         exit(EXIT_SUCCESS);
 567 }