server.c

   1 /*
   2  * Copyright (C) 1997-2007 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  *
  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 <sys/types.h>
  67 #include <dirent.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 "send.h"
  80 #include "net.h"
  81 #include "daemon.h"
  82 #include "ipc.h"
  83 #include "fd.h"
  84 #include "list.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 /** the file containing user information (public key, permissions) */
 110 char *user_list_file = NULL;
 111
 112 extern void dccp_send_init(struct sender *);
 113 extern void http_send_init(struct sender *);
 114 extern void ortp_send_init(struct sender *);
 115
 116 /** the list of supported senders */
 117 struct sender senders[] = {
 118         {
 119                 .name = "http",
 120                 .init = http_send_init,
 121         },
 122         {
 123                 .name = "dccp",
 124                 .init = dccp_send_init,
 125         },
 126 #ifdef HAVE_ORTP
 127         {
 128                 .name = "ortp",
 129                 .init = ortp_send_init,
 130         },
 131 #endif
 132         {
 133                 .name = NULL,
 134         }
 135 };
 136
 137
 138 /* global variables for server-internal use */
 139 static FILE *logfile;
 140 static int mmd_mutex, mmd_shm_id;
 141 static int signal_pipe;
 142
 143 /**
 144  * para_server's log function
 145  *
 146  * \param ll the log level
 147  * \param fmt the format string describing the log message
 148  */
 149 void para_log(int ll, const char* fmt,...)
 150 {
 151         va_list argp;
 152         FILE *outfd;
 153         struct tm *tm;
 154         time_t t1;
 155         char str[MAXLINE] = "";
 156         pid_t mypid;
 157
 158         if (ll < conf.loglevel_arg)
 159                 return;
 160         outfd = logfile? logfile : stderr;
 161         time(&t1);
 162         tm = localtime(&t1);
 163         strftime(str, MAXLINE, "%b %d %H:%M:%S", tm);
 164         fprintf(outfd, "%s ", str);
 165         if (conf.loglevel_arg <= INFO)
 166                 fprintf(outfd, "%i: ", ll);
 167         mypid = getpid();
 168         if (conf.loglevel_arg <= INFO)
 169                 fprintf(outfd, "(%d) ", (int)mypid);
 170         va_start(argp, fmt);
 171         vfprintf(outfd, fmt, argp);
 172         va_end(argp);
 173 }
 174
 175 /*
 176  * setup shared memory area and get mutex for locking
 177  */
 178 static void shm_init(void)
 179 {
 180         void *shm;
 181         int ret = shm_new(sizeof(struct misc_meta_data));
 182
 183         if (ret < 0)
 184                 goto err_out;
 185
 186         ret = shm_attach(ret, ATTACH_RW, &shm);
 187         if (ret < 0)
 188                 goto err_out;
 189         mmd = shm;
 190         mmd_shm_id = ret;
 191
 192         ret = mutex_new();
 193         if (ret < 0)
 194                 goto err_out;
 195         mmd_mutex = ret;
 196
 197         mmd->num_played = 0;
 198         mmd->num_commands = 0;
 199         mmd->events = 0;
 200         mmd->num_connects = 0;
 201         mmd->active_connections = 0;
 202         mmd->vss_status_flags = VSS_NEXT;
 203         mmd->new_vss_status_flags = VSS_NEXT;
 204         mmd->sender_cmd_data.cmd_num = -1;
 205         return;
 206 err_out:
 207         PARA_EMERG_LOG("%s", PARA_STRERROR(-ret));
 208         exit(EXIT_FAILURE);
 209 }
 210
 211 /**
 212  * lock the shared memory area containing the mmd struct
 213  *
 214  * \sa semop(2), struct misc_meta_data.
 215  */
 216 void mmd_lock(void)
 217 {
 218         mutex_lock(mmd_mutex);
 219 }
 220
 221 /**
 222  * unlock the shared memory area containing the mmd struct
 223  *
 224  * \sa semop(2), struct misc_meta_data
 225  */
 226
 227 void mmd_unlock(void)
 228 {
 229         mutex_unlock(mmd_mutex);
 230 }
 231
 232 static void parse_config(int override)
 233 {
 234         char *home = para_homedir();
 235         struct stat statbuf;
 236         int ret;
 237         char *cf;
 238
 239         if (conf.config_file_given)
 240                 cf = para_strdup(conf.config_file_arg);
 241         else
 242                 cf = make_message("%s/.paraslash/server.conf", home);
 243         free(user_list_file);
 244         if (!conf.user_list_given)
 245                 user_list_file = make_message("%s/.paraslash/server.users", home);
 246         else
 247                 user_list_file = para_strdup(conf.user_list_arg);
 248         ret = stat(cf, &statbuf);
 249         if (ret && conf.config_file_given) {
 250                 ret = -1;
 251                 PARA_EMERG_LOG("can not stat config file %s\n", cf);
 252                 goto out;
 253         }
 254         if (!ret) {
 255                 int tmp = conf.daemon_given;
 256                 struct server_cmdline_parser_params params = {
 257                         .override = override,
 258                         .initialize = 0,
 259                         .check_required = 0,
 260                         .check_ambiguity = 0
 261                 };
 262                 server_cmdline_parser_config_file(cf, &conf, &params);
 263                 conf.daemon_given = tmp;
 264         }
 265         /* logfile */
 266         if (!conf.logfile_given && conf.daemon_given) {
 267                 ret = -1;
 268                 PARA_EMERG_LOG("%s", "daemon, but no log file\n");
 269                 goto out;
 270         }
 271         if (conf.logfile_given)
 272                 logfile = open_log(conf.logfile_arg);
 273         ret = 1;
 274 out:
 275         free(cf);
 276         free(home);
 277         if (ret > 0)
 278                 return;
 279         free(user_list_file);
 280         user_list_file = NULL;
 281         exit(EXIT_FAILURE);
 282 }
 283
 284 static void setup_signal_handling(void)
 285 {
 286         int ret = 0;
 287
 288         signal_pipe = para_signal_init();
 289
 290         PARA_NOTICE_LOG("setting up signal handlers\n");
 291         ret += para_install_sighandler(SIGINT);
 292         ret += para_install_sighandler(SIGTERM);
 293         ret += para_install_sighandler(SIGHUP);
 294         ret += para_install_sighandler(SIGCHLD);
 295         ret += para_install_sighandler(SIGUSR1);
 296         signal(SIGPIPE, SIG_IGN);
 297         if (ret != 5) {
 298                 PARA_EMERG_LOG("%s", "could not install signal handlers\n");
 299                 exit(EXIT_FAILURE);
 300         }
 301         add_close_on_fork_list(signal_pipe);
 302 }
 303
 304 static unsigned init_network(void)
 305 {
 306         int fd, ret = para_listen(AF_UNSPEC, IPPROTO_TCP, conf.port_arg);
 307
 308         if (ret < 0)
 309                 goto err;
 310         fd = ret;
 311         ret = mark_fd_nonblocking(fd);
 312         if (ret < 0)
 313                 goto err;
 314         add_close_on_fork_list(fd); /* child doesn't need the listener */
 315         return fd;
 316 err:
 317         PARA_EMERG_LOG("%s\n", PARA_STRERROR(-ret));
 318         exit(EXIT_FAILURE);
 319 }
 320
 321 static void init_random_seed(void)
 322 {
 323         int fd, ret = -1;
 324         unsigned int seed;
 325         size_t len = sizeof(unsigned int);
 326
 327         fd = open("/dev/urandom", O_RDONLY);
 328         if (fd < 0)
 329                 goto out;
 330         ret = -2;
 331         if (read(fd, &seed, len) != len)
 332                 goto out;
 333         srandom(seed);
 334         ret = 1;
 335 out:
 336         if (fd >= 0)
 337                 close(fd);
 338         if (ret > 0)
 339                 return;
 340         PARA_EMERG_LOG("can not seed pseudo random generator (ret = %d)\n",
 341                 ret);
 342         exit(EXIT_FAILURE);
 343 }
 344
 345 uint32_t afs_socket_cookie;
 346 int afs_socket;
 347 static pid_t afs_pid;
 348
 349 static void init_afs(void)
 350 {
 351         int ret, afs_server_socket[2];
 352
 353         ret = socketpair(PF_UNIX, SOCK_DGRAM, 0, afs_server_socket);
 354         if (ret < 0)
 355                 exit(EXIT_FAILURE);
 356         afs_socket_cookie = para_random((uint32_t)-1);
 357         afs_pid = fork();
 358         if (afs_pid < 0)
 359                 exit(EXIT_FAILURE);
 360         if (!afs_pid) { /* child (afs) */
 361                 close(afs_server_socket[0]);
 362                 afs_init(afs_socket_cookie, afs_server_socket[1]);
 363         }
 364         close(afs_server_socket[1]);
 365         afs_socket = afs_server_socket[0];
 366         ret = mark_fd_nonblocking(afs_socket);
 367         if (ret < 0)
 368                 exit(EXIT_FAILURE);
 369         add_close_on_fork_list(afs_socket);
 370         PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n", afs_socket,
 371                 (unsigned) afs_socket_cookie);
 372 }
 373
 374
 375 static unsigned server_init(int argc, char **argv)
 376 {
 377         /* connector's address information */
 378         int sockfd;
 379
 380         init_random_seed();
 381         /* parse command line options */
 382         server_cmdline_parser(argc, argv, &conf);
 383         HANDLE_VERSION_FLAG("server", conf);
 384         para_drop_privileges(conf.user_arg, conf.group_arg);
 385         /* parse config file, open log and set defaults */
 386         parse_config(0);
 387         log_welcome("para_server", conf.loglevel_arg);
 388         shm_init(); /* init mmd struct */
 389         server_uptime(UPTIME_SET); /* reset server uptime */
 390         init_user_list(user_list_file);
 391         /* become daemon */
 392         if (conf.daemon_given)
 393                 daemon_init();
 394         PARA_NOTICE_LOG("initializing audio format handlers\n");
 395         afh_init();
 396         PARA_NOTICE_LOG("initializing virtual streaming system\n");
 397         vss_init();
 398         mmd->server_pid = getpid();
 399         setup_signal_handling();
 400         PARA_NOTICE_LOG("initializing the audio file selector\n");
 401         init_afs();
 402         mmd_lock();
 403         /* init network socket */
 404         PARA_NOTICE_LOG("initializing tcp command socket\n");
 405         sockfd = init_network();
 406         PARA_NOTICE_LOG("server init complete\n");
 407         return sockfd;
 408 }
 409
 410 /*
 411  * called when server gets SIGHUP or when client invokes hup command.
 412  */
 413 static void handle_sighup(void)
 414 {
 415         PARA_NOTICE_LOG("%s", "SIGHUP\n");
 416         close_log(logfile); /* gets reopened if necessary by parse_config */
 417         logfile = NULL;
 418         parse_config(1); /* reopens log */
 419         init_user_list(user_list_file); /* reload user list */
 420         if (afs_pid)
 421                 kill(afs_pid, SIGHUP);
 422 }
 423
 424 static void status_refresh(void)
 425 {
 426         static int prev_uptime = -1, prev_events = -1;
 427         int uptime = server_uptime(UPTIME_GET), ret = 1;
 428
 429         if (prev_events != mmd->events)
 430                 goto out;
 431         if (mmd->new_vss_status_flags != mmd->vss_status_flags)
 432                 goto out;
 433         if (uptime / 60 != prev_uptime / 60)
 434                 goto out;
 435         ret = 0;
 436 out:
 437         prev_uptime = uptime;
 438         prev_events = mmd->events;
 439         mmd->vss_status_flags = mmd->new_vss_status_flags;
 440         if (ret) {
 441                 PARA_DEBUG_LOG("%d events, forcing status update\n",
 442                         mmd->events);
 443                 killpg(0, SIGUSR1);
 444         }
 445 }
 446
 447 /**
 448  * the main function of para_server
 449  *
 450  * \param argc usual argument count
 451  * \param argv usual argument vector
 452  *
 453  * \return EXIT_SUCCESS or EXIT_FAILURE
 454  *
 455  */
 456 int main(int argc, char *argv[])
 457 {
 458         /* listen on sock_fd, new connection on new_fd */
 459         int sockfd, new_fd;
 460         char *peer_name;
 461         int i, max_fileno, ret;
 462         pid_t chld_pid;
 463         fd_set rfds, wfds;
 464         struct timeval *timeout;
 465
 466         valid_fd_012();
 467         sockfd = server_init(argc, argv);
 468 repeat:
 469         FD_ZERO(&rfds);
 470         FD_ZERO(&wfds);
 471         max_fileno = -1;
 472         /* check socket and signal pipe in any case */
 473         para_fd_set(sockfd, &rfds, &max_fileno);
 474         para_fd_set(signal_pipe, &rfds, &max_fileno);
 475         timeout = vss_preselect(&rfds, &wfds, &max_fileno);
 476         status_refresh();
 477         for (i = 0; senders[i].name; i++) {
 478                 if (senders[i].status != SENDER_ON)
 479                         continue;
 480                 if (!senders[i].pre_select)
 481                         continue;
 482                 senders[i].pre_select(&max_fileno, &rfds, &wfds);
 483         }
 484         mmd_unlock();
 485         ret = para_select(max_fileno + 1, &rfds, &wfds, timeout);
 486         mmd_lock();
 487         vss_post_select(&rfds, &wfds);
 488         if (ret < 0)
 489                 goto repeat;
 490         for (i = 0; senders[i].name; i++) {
 491                 if (senders[i].status != SENDER_ON)
 492                         continue;
 493                 if (!senders[i].post_select)
 494                         continue;
 495                 senders[i].post_select(&rfds, &wfds);
 496         }
 497         vss_send_chunk();
 498         status_refresh();
 499         if (FD_ISSET(signal_pipe, &rfds)) {
 500                 int sig;
 501                 pid_t pid;
 502                 sig = para_next_signal();
 503                 switch (sig) {
 504                 case SIGHUP:
 505                         handle_sighup();
 506                         break;
 507                 case SIGCHLD:
 508                         for (;;) {
 509                                 ret = para_reap_child(&pid);
 510                                 if (ret <= 0)
 511                                         break;
 512                                 if (pid != afs_pid)
 513                                         continue;
 514                                 PARA_EMERG_LOG("fatal: afs died\n");
 515                                 goto genocide;
 516                         }
 517                         break;
 518                 /* die on sigint/sigterm. Kill all children too. */
 519                 case SIGINT:
 520                 case SIGTERM:
 521                         PARA_EMERG_LOG("terminating on signal %d\n", sig);
 522 genocide:
 523                         kill(0, SIGTERM);
 524                         mutex_destroy(mmd_mutex);
 525                         shm_detach(mmd);
 526                         shm_destroy(mmd_shm_id);
 527
 528                         exit(EXIT_FAILURE);
 529                 }
 530         }
 531         if (mmd->sender_cmd_data.cmd_num >= 0) {
 532                 int num = mmd->sender_cmd_data.cmd_num,
 533                         s = mmd->sender_cmd_data.sender_num;
 534
 535                 if (senders[s].client_cmds[num])
 536                         senders[s].client_cmds[num](&mmd->sender_cmd_data);
 537                 mmd->sender_cmd_data.cmd_num = -1;
 538         }
 539         if (!FD_ISSET(sockfd, &rfds))
 540                 goto repeat;
 541
 542         new_fd = para_accept(sockfd, NULL, 0);
 543         if (new_fd < 0)
 544                 goto repeat;
 545         peer_name = remote_name(new_fd);
 546         PARA_INFO_LOG("got connection from %s, forking\n", peer_name);
 547         mmd->num_connects++;
 548         mmd->active_connections++;
 549         random();
 550         chld_pid = fork();
 551         if (chld_pid < 0) {
 552                 PARA_CRIT_LOG("%s", "fork failed\n");
 553                 goto repeat;
 554         }
 555         if (chld_pid) {
 556                 close(new_fd);
 557                 /* parent keeps accepting connections */
 558                 goto repeat;
 559         }
 560         alarm(ALARM_TIMEOUT);
 561         close_listed_fds();
 562         para_signal_shutdown();
 563         /*
 564          * put info on who we are serving into argv[0] to make
 565          * client ip visible in top/ps
 566          */
 567         for (i = argc - 1; i >= 0; i--)
 568                 memset(argv[i], 0, strlen(argv[i]));
 569         sprintf(argv[0], "para_server (serving %s)", peer_name);
 570         return handle_connect(new_fd, peer_name);
 571 }