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