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 "list.h"
  81 #include "send.h"
  82 #include "net.h"
  83 #include "daemon.h"
  84 #include "ipc.h"
  85 #include "fd.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 /* global variables for server-internal use */
 114 static FILE *logfile;
 115 static int mmd_mutex, mmd_shm_id;
 116 static int signal_pipe;
 117
 118 struct server_command_task {
 119         /** TCP port on which para_server listens for connections. */
 120         int listen_fd;
 121         /** Copied from para_server's main function. */
 122         int argc;
 123         /** Argument vector passed to para_server's main function. */
 124         char **argv;
 125         /** The command task structure for scheduling. */
 126         //struct task task;
 127         char dummy;
 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 setup_signal_handling(void)
 266 {
 267         signal_pipe = para_signal_init(); /* always successful */
 268
 269         PARA_NOTICE_LOG("setting up signal handlers\n");
 270         if (para_install_sighandler(SIGINT) < 0)
 271                 goto err;
 272         if (para_install_sighandler(SIGTERM) < 0)
 273                 goto err;
 274         if (para_install_sighandler(SIGHUP) < 0)
 275                 goto err;
 276         if (para_install_sighandler(SIGCHLD) < 0)
 277                 goto err;
 278         if (signal(SIGPIPE, SIG_IGN) == SIG_ERR)
 279                 goto err;
 280         if (signal(SIGUSR1, SIG_IGN) == SIG_ERR)
 281                 goto err;
 282         add_close_on_fork_list(signal_pipe);
 283         return;
 284 err:
 285         PARA_EMERG_LOG("could not install signal handlers\n");
 286         exit(EXIT_FAILURE);
 287 }
 288
 289 static void init_command_task(struct server_command_task *sct)
 290 {
 291         int ret;
 292
 293         PARA_NOTICE_LOG("initializing tcp command socket\n");
 294         ret = para_listen(AF_UNSPEC, IPPROTO_TCP, conf.port_arg);
 295         if (ret < 0)
 296                 goto err;
 297         sct->listen_fd = ret;
 298         ret = mark_fd_nonblocking(sct->listen_fd);
 299         if (ret < 0)
 300                 goto err;
 301         add_close_on_fork_list(sct->listen_fd); /* child doesn't need the listener */
 302         return;
 303 err:
 304         PARA_EMERG_LOG("%s\n", para_strerror(-ret));
 305         exit(EXIT_FAILURE);
 306 }
 307
 308 static void init_random_seed(void)
 309 {
 310         unsigned int seed;
 311         int fd, ret = para_open("/dev/urandom", O_RDONLY, 0);
 312
 313         if (ret < 0)
 314                 goto err;
 315         fd = ret;
 316         ret = read(fd, &seed, sizeof(seed));
 317         if (ret < 0) {
 318                 ret = -ERRNO_TO_PARA_ERROR(errno);
 319                 goto out;
 320         }
 321         if (ret != sizeof(seed)) {
 322                 ret = -ERRNO_TO_PARA_ERROR(EIO);
 323                 goto out;
 324         }
 325         srandom(seed);
 326         ret = 1;
 327 out:
 328         close(fd);
 329         if (ret >= 0)
 330                 return;
 331 err:
 332         PARA_EMERG_LOG("can not seed pseudo random number generator: %s\n",
 333                 para_strerror(-ret));
 334         exit(EXIT_FAILURE);
 335 }
 336
 337 uint32_t afs_socket_cookie;
 338 int afs_socket;
 339 static pid_t afs_pid;
 340
 341 static void init_afs(void)
 342 {
 343         int ret, afs_server_socket[2];
 344
 345         ret = socketpair(PF_UNIX, SOCK_DGRAM, 0, afs_server_socket);
 346         if (ret < 0)
 347                 exit(EXIT_FAILURE);
 348         afs_socket_cookie = para_random((uint32_t)-1);
 349         afs_pid = fork();
 350         if (afs_pid < 0)
 351                 exit(EXIT_FAILURE);
 352         if (!afs_pid) { /* child (afs) */
 353                 close(afs_server_socket[0]);
 354                 afs_init(afs_socket_cookie, afs_server_socket[1]);
 355         }
 356         close(afs_server_socket[1]);
 357         afs_socket = afs_server_socket[0];
 358         ret = mark_fd_nonblocking(afs_socket);
 359         if (ret < 0)
 360                 exit(EXIT_FAILURE);
 361         add_close_on_fork_list(afs_socket);
 362         PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n", afs_socket,
 363                 (unsigned) afs_socket_cookie);
 364 }
 365
 366 static void server_init(int argc, char **argv)
 367 {
 368         /* connector's address information */
 369         struct server_cmdline_parser_params params = {
 370                 .override = 0,
 371                 .initialize = 1,
 372                 .check_required = 0,
 373                 .check_ambiguity = 0,
 374                 .print_errors = 1
 375         };
 376         init_random_seed();
 377         /* parse command line options */
 378         server_cmdline_parser_ext(argc, argv, &conf, &params);
 379         HANDLE_VERSION_FLAG("server", conf);
 380         para_drop_privileges(conf.user_arg, conf.group_arg);
 381         /* parse config file, open log and set defaults */
 382         parse_config(0);
 383         log_welcome("para_server", conf.loglevel_arg);
 384         shm_init(); /* init mmd struct */
 385         server_uptime(UPTIME_SET); /* reset server uptime */
 386         init_user_list(user_list_file);
 387         /* become daemon */
 388         if (conf.daemon_given)
 389                 daemon_init();
 390         PARA_NOTICE_LOG("initializing audio format handlers\n");
 391         afh_init();
 392         mmd->server_pid = getpid();
 393         setup_signal_handling();
 394         PARA_NOTICE_LOG("initializing the audio file selector\n");
 395         init_afs();
 396         PARA_NOTICE_LOG("initializing virtual streaming system\n");
 397         vss_init();
 398         mmd_lock();
 399         PARA_NOTICE_LOG("server init complete\n");
 400 }
 401
 402 /*
 403  * called when server gets SIGHUP or when client invokes hup command.
 404  */
 405 static void handle_sighup(void)
 406 {
 407         PARA_NOTICE_LOG("SIGHUP\n");
 408         close_log(logfile); /* gets reopened if necessary by parse_config */
 409         logfile = NULL;
 410         parse_config(1); /* reopens log */
 411         init_user_list(user_list_file); /* reload user list */
 412         if (afs_pid)
 413                 kill(afs_pid, SIGHUP);
 414 }
 415
 416 static void status_refresh(void)
 417 {
 418         static int prev_uptime = -1, prev_events = -1;
 419         int uptime = server_uptime(UPTIME_GET), ret = 1;
 420
 421         if (prev_events != mmd->events)
 422                 goto out;
 423         if (mmd->new_vss_status_flags != mmd->vss_status_flags)
 424                 goto out;
 425         if (uptime / 60 != prev_uptime / 60)
 426                 goto out;
 427         ret = 0;
 428 out:
 429         prev_uptime = uptime;
 430         prev_events = mmd->events;
 431         mmd->vss_status_flags = mmd->new_vss_status_flags;
 432         if (ret) {
 433                 PARA_DEBUG_LOG("%d events, forcing status update\n",
 434                         mmd->events);
 435                 killpg(0, SIGUSR1);
 436         }
 437 }
 438
 439 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
 440                 struct timeval *timeout_tv)
 441 {
 442         int ret;
 443
 444         status_refresh();
 445         mmd_unlock();
 446         ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
 447         mmd_lock();
 448         return ret;
 449 }
 450
 451 static void command_pre_select(int *max_fileno, fd_set *rfds, char *dummy_ptr)
 452 {
 453         struct server_command_task *sct = container_of(dummy_ptr, struct server_command_task, dummy);
 454         para_fd_set(sct->listen_fd, rfds, max_fileno);
 455 }
 456
 457 static void command_post_select(fd_set *rfds, char *dummy_ptr)
 458 {
 459         struct server_command_task *sct = container_of(dummy_ptr, struct server_command_task, dummy);
 460
 461         int new_fd, ret;
 462         char *peer_name;
 463         pid_t child_pid;
 464
 465         if (!FD_ISSET(sct->listen_fd, rfds))
 466                 return;
 467         ret = para_accept(sct->listen_fd, NULL, 0);
 468         if (ret < 0)
 469                 goto out;
 470         new_fd = ret;
 471         peer_name = remote_name(new_fd);
 472         PARA_INFO_LOG("got connection from %s, forking\n", peer_name);
 473         mmd->num_connects++;
 474         mmd->active_connections++;
 475         random();
 476         child_pid = fork();
 477         if (child_pid < 0) {
 478                 ret = -ERRNO_TO_PARA_ERROR(errno);
 479                 goto out;
 480         }
 481         if (child_pid) {
 482                 close(new_fd);
 483                 /* parent keeps accepting connections */
 484                 return;
 485         }
 486         alarm(ALARM_TIMEOUT);
 487         close_listed_fds();
 488         para_signal_shutdown();
 489         /*
 490          * put info on who we are serving into argv[0] to make
 491          * client ip visible in top/ps
 492          */
 493 //      for (i = argc - 1; i >= 0; i--)
 494 //              memset(argv[i], 0, strlen(argv[i]));
 495 //      sprintf(argv[0], "para_server (serving %s)", peer_name);
 496         return handle_connect(new_fd, peer_name);
 497 out:
 498         if (ret < 0)
 499                 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
 500 }
 501
 502 /**
 503  * the main function of para_server
 504  *
 505  * \param argc usual argument count
 506  * \param argv usual argument vector
 507  *
 508  * \return EXIT_SUCCESS or EXIT_FAILURE
 509  *
 510  */
 511 int main(int argc, char *argv[])
 512 {
 513         int max_fileno, ret;
 514         fd_set rfds, wfds;
 515         struct timeval *timeout;
 516         struct server_command_task server_command_task_struct;
 517
 518
 519         valid_fd_012();
 520         server_init(argc, argv);
 521         init_command_task(&server_command_task_struct);
 522 repeat:
 523         FD_ZERO(&rfds);
 524         FD_ZERO(&wfds);
 525         max_fileno = -1;
 526         command_pre_select(&max_fileno, &rfds, &server_command_task_struct.dummy);
 527         para_fd_set(signal_pipe, &rfds, &max_fileno);
 528         timeout = vss_preselect(&rfds, &wfds, &max_fileno);
 529         server_select(max_fileno + 1, &rfds, &wfds, timeout);
 530         vss_post_select(&rfds, &wfds);
 531         if (FD_ISSET(signal_pipe, &rfds)) {
 532                 int sig;
 533                 pid_t pid;
 534                 sig = para_next_signal();
 535                 switch (sig) {
 536                 case SIGHUP:
 537                         handle_sighup();
 538                         break;
 539                 case SIGCHLD:
 540                         for (;;) {
 541                                 ret = para_reap_child(&pid);
 542                                 if (ret <= 0)
 543                                         break;
 544                                 if (pid != afs_pid)
 545                                         continue;
 546                                 PARA_EMERG_LOG("fatal: afs died\n");
 547                                 goto genocide;
 548                         }
 549                         break;
 550                 /* die on sigint/sigterm. Kill all children too. */
 551                 case SIGINT:
 552                 case SIGTERM:
 553                         PARA_EMERG_LOG("terminating on signal %d\n", sig);
 554 genocide:
 555                         kill(0, SIGTERM);
 556                         mutex_destroy(mmd_mutex);
 557                         shm_detach(mmd);
 558                         shm_destroy(mmd_shm_id);
 559
 560                         exit(EXIT_FAILURE);
 561                 }
 562         }
 563         command_post_select(&rfds, &server_command_task_struct.dummy);
 564         goto repeat;
 565 }