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 #include "color.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 /** A random value used in child context for authentication. */
 111 uint32_t afs_socket_cookie;
 112
 113 /** The mutex protecting the shared memory area containing the mmd struct. */
 114 int mmd_mutex;
 115
 116 /* global variables for server-internal use */
 117 static FILE *logfile;
 118 /** The file containing user information (public key, permissions). */
 119 static char *user_list_file = NULL;
 120 static int mmd_shm_id;
 121
 122
 123 /** The task responsible for server command handling. */
 124 struct server_command_task {
 125         /** TCP port on which para_server listens for connections. */
 126         int listen_fd;
 127         /** Copied from para_server's main function. */
 128         int argc;
 129         /** Argument vector passed to para_server's main function. */
 130         char **argv;
 131         /** The command task structure for scheduling. */
 132         struct task task;
 133 };
 134
 135 static int want_colors(void)
 136 {
 137         if (conf.color_arg == color_arg_no)
 138                 return 0;
 139         if (conf.color_arg == color_arg_yes)
 140                 return 1;
 141         if (logfile)
 142                 return 0;
 143         return isatty(STDERR_FILENO);
 144 }
 145
 146 static int get_loglevel_by_name(const char *txt, size_t n)
 147 {
 148         if (!strncasecmp(txt, "debug", n))
 149                 return LL_DEBUG;
 150         if (!strncasecmp(txt, "info", n))
 151                 return LL_INFO;
 152         if (!strncasecmp(txt, "notice", n))
 153                 return LL_NOTICE;
 154         if (!strncasecmp(txt, "warning", n))
 155                 return LL_WARNING;
 156         if (!strncasecmp(txt, "error", n))
 157                 return LL_ERROR;
 158         if (!strncasecmp(txt, "crit", n))
 159                 return LL_CRIT;
 160         if (!strncasecmp(txt, "emerg", n))
 161                 return LL_EMERG;
 162         return -1;
 163 }
 164
 165 static char log_colors[NUM_LOGLEVELS][COLOR_MAXLEN];
 166
 167 static void init_colors_or_die(void)
 168 {
 169         int ret, i;
 170         static const char *default_log_colors[NUM_LOGLEVELS] = {
 171                         [LL_DEBUG] = "normal",
 172                         [LL_INFO] = "white bold",
 173                         [LL_NOTICE] = "cyan bold",
 174                         [LL_WARNING] = "green bold",
 175                         [LL_ERROR] = "yellow bold",
 176                         [LL_CRIT] = "magenta bold",
 177                         [LL_EMERG] = "red bold",
 178         };
 179
 180         for (i = 0; i < NUM_LOGLEVELS; i++) {
 181                 ret = color_parse(default_log_colors[i], log_colors[i]);
 182                 assert(ret >= 0);
 183         }
 184
 185         for (i = 0; i < conf.log_color_given; i++) {
 186                 char *arg = conf.log_color_arg[i], *p = strchr(arg, ':');
 187                 int ll;
 188                 if (!p)
 189                         goto err;
 190                 ret = get_loglevel_by_name(arg, p - arg);
 191                 if (ret < 0)
 192                         goto err;
 193                 ll = ret;
 194                 p++;
 195                 ret = color_parse(p, log_colors[ll]);
 196                 if (ret < 0)
 197                         goto err;
 198         }
 199         return;
 200 err:
 201         PARA_EMERG_LOG("color syntax error, arg %d (%s)\n", i,
 202                 conf.log_color_arg[i]);
 203         exit(EXIT_FAILURE);
 204 }
 205
 206 /**
 207  * Para_server's log function.
 208  *
 209  * \param ll The log level.
 210  * \param fmt The format string describing the log message.
 211  */
 212 __printf_2_3 void para_log(int ll, const char* fmt,...)
 213 {
 214         va_list argp;
 215         FILE *fp;
 216         struct tm *tm;
 217         time_t t1;
 218         char *color, str[MAXLINE] = "";
 219
 220         ll = PARA_MIN(ll, NUM_LOGLEVELS - 1);
 221         ll = PARA_MAX(ll, LL_DEBUG);
 222         if (ll < conf.loglevel_arg)
 223                 return;
 224
 225         fp = logfile? logfile : stderr;
 226         color = want_colors()? log_colors[ll] : NULL;
 227
 228         if (color)
 229                 fprintf(fp, "%s", color);
 230         /* date and time */
 231         time(&t1);
 232         tm = localtime(&t1);
 233         strftime(str, MAXLINE, "%b %d %H:%M:%S", tm);
 234         fprintf(fp, "%s ", str);
 235         /* loglevel */
 236         if (conf.loglevel_arg <= LL_INFO)
 237                 fprintf(fp, "%i: ", ll);
 238         if (conf.loglevel_arg <= LL_INFO) { /* log pid */
 239                 pid_t mypid = getpid();
 240                 fprintf(fp, "(%d) ", (int)mypid);
 241         }
 242         va_start(argp, fmt);
 243         vfprintf(fp, fmt, argp);
 244         va_end(argp);
 245         if (color)
 246                 fprintf(fp, "%s", COLOR_RESET);
 247 }
 248
 249 /*
 250  * setup shared memory area and get mutex for locking
 251  */
 252 static void init_ipc_or_die(void)
 253 {
 254         void *shm;
 255         int ret = shm_new(sizeof(struct misc_meta_data));
 256
 257         if (ret < 0)
 258                 goto err_out;
 259
 260         ret = shm_attach(ret, ATTACH_RW, &shm);
 261         if (ret < 0)
 262                 goto err_out;
 263         mmd = shm;
 264         mmd_shm_id = ret;
 265
 266         ret = mutex_new();
 267         if (ret < 0)
 268                 goto err_out;
 269         mmd_mutex = ret;
 270
 271         mmd->num_played = 0;
 272         mmd->num_commands = 0;
 273         mmd->events = 0;
 274         mmd->num_connects = 0;
 275         mmd->active_connections = 0;
 276         mmd->vss_status_flags = VSS_NEXT;
 277         mmd->new_vss_status_flags = VSS_NEXT;
 278         return;
 279 err_out:
 280         PARA_EMERG_LOG("%s\n", para_strerror(-ret));
 281         exit(EXIT_FAILURE);
 282 }
 283
 284 /**
 285  * (Re-)read the server configuration files.
 286  *
 287  * \param override Passed to gengetopt to activate the override feature.
 288  *
 289  * This function also re-opens the logfile and sets the global \a
 290  * user_list_file variable.
 291  */
 292 void parse_config_or_die(int override)
 293 {
 294         char *home = para_homedir();
 295         struct stat statbuf;
 296         int ret;
 297         char *cf;
 298
 299         close_log(logfile);
 300         logfile = NULL;
 301         if (conf.config_file_given)
 302                 cf = para_strdup(conf.config_file_arg);
 303         else
 304                 cf = make_message("%s/.paraslash/server.conf", home);
 305         free(user_list_file);
 306         if (!conf.user_list_given)
 307                 user_list_file = make_message("%s/.paraslash/server.users", home);
 308         else
 309                 user_list_file = para_strdup(conf.user_list_arg);
 310         ret = stat(cf, &statbuf);
 311         if (ret && conf.config_file_given) {
 312                 ret = -1;
 313                 PARA_EMERG_LOG("can not stat config file %s\n", cf);
 314                 goto out;
 315         }
 316         if (!ret) {
 317                 int tmp = conf.daemon_given;
 318                 struct server_cmdline_parser_params params = {
 319                         .override = override,
 320                         .initialize = 0,
 321                         .check_required = 1,
 322                         .check_ambiguity = 0,
 323                         .print_errors = 1
 324                 };
 325                 server_cmdline_parser_config_file(cf, &conf, &params);
 326                 conf.daemon_given = tmp;
 327         }
 328         if (conf.logfile_given)
 329                 logfile = open_log(conf.logfile_arg);
 330         if (want_colors())
 331                 init_colors_or_die();
 332         ret = 1;
 333 out:
 334         free(cf);
 335         free(home);
 336         if (ret > 0)
 337                 return;
 338         free(user_list_file);
 339         user_list_file = NULL;
 340         exit(EXIT_FAILURE);
 341 }
 342
 343 static void signal_pre_select(struct sched *s, struct task *t)
 344 {
 345         struct signal_task *st = container_of(t, struct signal_task, task);
 346         para_fd_set(st->fd, &s->rfds, &s->max_fileno);
 347 }
 348
 349 /*
 350  * called when server gets SIGHUP or when client invokes hup command.
 351  */
 352 static void handle_sighup(void)
 353 {
 354         PARA_NOTICE_LOG("SIGHUP\n");
 355         parse_config_or_die(1); /* reopens log */
 356         init_user_list(user_list_file); /* reload user list */
 357         if (mmd->afs_pid)
 358                 kill(mmd->afs_pid, SIGHUP);
 359 }
 360
 361 static void signal_post_select(struct sched *s, struct task *t)
 362 {
 363         struct signal_task *st = container_of(t, struct signal_task, task);
 364
 365         if (!FD_ISSET(st->fd, &s->rfds))
 366                 return;
 367
 368         st->signum = para_next_signal();
 369         switch (st->signum) {
 370         case SIGHUP:
 371                 handle_sighup();
 372                 break;
 373         case SIGCHLD:
 374                 for (;;) {
 375                         pid_t pid;
 376                         int ret = para_reap_child(&pid);
 377                         if (ret <= 0)
 378                                 break;
 379                         if (pid != mmd->afs_pid)
 380                                 continue;
 381                         PARA_EMERG_LOG("fatal: afs died\n");
 382                         goto genocide;
 383                 }
 384                 break;
 385         /* die on sigint/sigterm. Kill all children too. */
 386         case SIGINT:
 387         case SIGTERM:
 388                 PARA_EMERG_LOG("terminating on signal %d\n", st->signum);
 389 genocide:
 390                 kill(0, SIGTERM);
 391                 mutex_destroy(mmd_mutex);
 392                 shm_detach(mmd);
 393                 shm_destroy(mmd_shm_id);
 394
 395                 exit(EXIT_FAILURE);
 396         }
 397 }
 398
 399 static void init_signal_task(void)
 400 {
 401         static struct signal_task signal_task_struct,
 402                 *st = &signal_task_struct;
 403
 404         st->task.pre_select = signal_pre_select;
 405         st->task.post_select = signal_post_select;
 406         sprintf(st->task.status, "signal task");
 407
 408         st->fd = para_signal_init(); /* always successful */
 409
 410         PARA_NOTICE_LOG("setting up signal handlers\n");
 411         if (para_install_sighandler(SIGINT) < 0)
 412                 goto err;
 413         if (para_install_sighandler(SIGTERM) < 0)
 414                 goto err;
 415         if (para_install_sighandler(SIGHUP) < 0)
 416                 goto err;
 417         if (para_install_sighandler(SIGCHLD) < 0)
 418                 goto err;
 419         if (signal(SIGPIPE, SIG_IGN) == SIG_ERR)
 420                 goto err;
 421         if (signal(SIGUSR1, SIG_IGN) == SIG_ERR)
 422                 goto err;
 423         add_close_on_fork_list(st->fd);
 424         register_task(&st->task);
 425         return;
 426 err:
 427         PARA_EMERG_LOG("could not install signal handlers\n");
 428         exit(EXIT_FAILURE);
 429 }
 430
 431 static void command_pre_select(struct sched *s, struct task *t)
 432 {
 433         struct server_command_task *sct = container_of(t, struct server_command_task, task);
 434         para_fd_set(sct->listen_fd, &s->rfds, &s->max_fileno);
 435 }
 436
 437 static void command_post_select(struct sched *s, struct task *t)
 438 {
 439         struct server_command_task *sct = container_of(t, struct server_command_task, task);
 440
 441         int new_fd, ret, i;
 442         char *peer_name;
 443         pid_t child_pid;
 444
 445         if (!FD_ISSET(sct->listen_fd, &s->rfds))
 446                 return;
 447         ret = para_accept(sct->listen_fd, NULL, 0);
 448         if (ret < 0)
 449                 goto out;
 450         new_fd = ret;
 451         peer_name = remote_name(new_fd);
 452         PARA_INFO_LOG("got connection from %s, forking\n", peer_name);
 453         mmd->num_connects++;
 454         mmd->active_connections++;
 455         random();
 456         child_pid = fork();
 457         if (child_pid < 0) {
 458                 ret = -ERRNO_TO_PARA_ERROR(errno);
 459                 goto out;
 460         }
 461         if (child_pid) {
 462                 close(new_fd);
 463                 /* parent keeps accepting connections */
 464                 return;
 465         }
 466         alarm(ALARM_TIMEOUT);
 467         close_listed_fds();
 468         para_signal_shutdown();
 469         /*
 470          * put info on who we are serving into argv[0] to make
 471          * client ip visible in top/ps
 472          */
 473         for (i = sct->argc - 1; i >= 0; i--)
 474                 memset(sct->argv[i], 0, strlen(sct->argv[i]));
 475         sprintf(sct->argv[0], "para_server (serving %s)", peer_name);
 476         return handle_connect(new_fd, peer_name);
 477 out:
 478         if (ret < 0)
 479                 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
 480 }
 481
 482 static void init_server_command_task(int argc, char **argv)
 483 {
 484         int ret;
 485         static struct server_command_task server_command_task_struct,
 486                 *sct = &server_command_task_struct;
 487
 488         PARA_NOTICE_LOG("initializing tcp command socket\n");
 489         sct->task.pre_select = command_pre_select;
 490         sct->task.post_select = command_post_select;
 491         sct->argc = argc;
 492         sct->argv = argv;
 493         ret = para_listen(AF_UNSPEC, IPPROTO_TCP, conf.port_arg);
 494         if (ret < 0)
 495                 goto err;
 496         sct->listen_fd = ret;
 497         ret = mark_fd_nonblocking(sct->listen_fd);
 498         if (ret < 0)
 499                 goto err;
 500         add_close_on_fork_list(sct->listen_fd); /* child doesn't need the listener */
 501         register_task(&sct->task);
 502         return;
 503 err:
 504         PARA_EMERG_LOG("%s\n", para_strerror(-ret));
 505         exit(EXIT_FAILURE);
 506 }
 507
 508 static void init_random_seed(void)
 509 {
 510         unsigned int seed;
 511         int fd, ret = para_open("/dev/urandom", O_RDONLY, 0);
 512
 513         if (ret < 0)
 514                 goto err;
 515         fd = ret;
 516         ret = read(fd, &seed, sizeof(seed));
 517         if (ret < 0) {
 518                 ret = -ERRNO_TO_PARA_ERROR(errno);
 519                 goto out;
 520         }
 521         if (ret != sizeof(seed)) {
 522                 ret = -ERRNO_TO_PARA_ERROR(EIO);
 523                 goto out;
 524         }
 525         srandom(seed);
 526         ret = 1;
 527 out:
 528         close(fd);
 529         if (ret >= 0)
 530                 return;
 531 err:
 532         PARA_EMERG_LOG("can not seed pseudo random number generator: %s\n",
 533                 para_strerror(-ret));
 534         exit(EXIT_FAILURE);
 535 }
 536
 537 static int init_afs(void)
 538 {
 539         int ret, afs_server_socket[2];
 540
 541         ret = socketpair(PF_UNIX, SOCK_DGRAM, 0, afs_server_socket);
 542         if (ret < 0)
 543                 exit(EXIT_FAILURE);
 544         afs_socket_cookie = para_random((uint32_t)-1);
 545         mmd->afs_pid = fork();
 546         if (mmd->afs_pid < 0)
 547                 exit(EXIT_FAILURE);
 548         if (!mmd->afs_pid) { /* child (afs) */
 549                 close(afs_server_socket[0]);
 550                 afs_init(afs_socket_cookie, afs_server_socket[1]);
 551         }
 552         close(afs_server_socket[1]);
 553         ret = mark_fd_nonblocking(afs_server_socket[0]);
 554         if (ret < 0)
 555                 exit(EXIT_FAILURE);
 556         add_close_on_fork_list(afs_server_socket[0]);
 557         PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
 558                 afs_server_socket[0], (unsigned) afs_socket_cookie);
 559         return afs_server_socket[0];
 560 }
 561
 562 static void server_init(int argc, char **argv)
 563 {
 564         struct server_cmdline_parser_params params = {
 565                 .override = 0,
 566                 .initialize = 1,
 567                 .check_required = 0,
 568                 .check_ambiguity = 0,
 569                 .print_errors = 1
 570         };
 571         int afs_socket;
 572
 573         valid_fd_012();
 574         init_random_seed();
 575         /* parse command line options */
 576         server_cmdline_parser_ext(argc, argv, &conf, &params);
 577         HANDLE_VERSION_FLAG("server", conf);
 578         drop_privileges_or_die(conf.user_arg, conf.group_arg);
 579         /* parse config file, open log and set defaults */
 580         parse_config_or_die(0);
 581         log_welcome("para_server", conf.loglevel_arg);
 582         init_ipc_or_die(); /* init mmd struct and mmd->lock */
 583         /* make sure, the global now pointer is uptodate */
 584         gettimeofday(now, NULL);
 585         server_uptime(UPTIME_SET); /* reset server uptime */
 586         init_user_list(user_list_file);
 587         /* become daemon */
 588         if (conf.daemon_given)
 589                 daemonize();
 590         PARA_NOTICE_LOG("initializing audio format handlers\n");
 591         afh_init();
 592         PARA_NOTICE_LOG("initializing the audio file selector\n");
 593         afs_socket = init_afs();
 594         init_signal_task();
 595         PARA_NOTICE_LOG("initializing virtual streaming system\n");
 596         init_vss_task(afs_socket);
 597         init_server_command_task(argc, argv);
 598         PARA_NOTICE_LOG("server init complete\n");
 599 }
 600
 601 static void status_refresh(void)
 602 {
 603         static int prev_uptime = -1, prev_events = -1;
 604         int uptime = server_uptime(UPTIME_GET), ret = 1;
 605
 606         if (prev_events != mmd->events)
 607                 goto out;
 608         if (mmd->new_vss_status_flags != mmd->vss_status_flags)
 609                 goto out_inc_events;
 610         if (uptime / 60 != prev_uptime / 60)
 611                 goto out_inc_events;
 612         return;
 613 out_inc_events:
 614         mmd->events++;
 615 out:
 616         prev_uptime = uptime;
 617         prev_events = mmd->events;
 618         mmd->vss_status_flags = mmd->new_vss_status_flags;
 619         if (ret) {
 620                 PARA_DEBUG_LOG("%d events, forcing status update\n",
 621                         mmd->events);
 622                 killpg(0, SIGUSR1);
 623         }
 624 }
 625
 626 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
 627                 struct timeval *timeout_tv)
 628 {
 629         int ret;
 630
 631         status_refresh();
 632         mutex_unlock(mmd_mutex);
 633         ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
 634         mutex_lock(mmd_mutex);
 635         return ret;
 636 }
 637
 638 /**
 639  * The main function of para_server.
 640  *
 641  * \param argc Usual argument count.
 642  * \param argv Usual argument vector.
 643  *
 644  * \return EXIT_SUCCESS or EXIT_FAILURE.
 645  */
 646 int main(int argc, char *argv[])
 647 {
 648         int ret;
 649         static struct sched s = {
 650                 .default_timeout = {
 651                         .tv_sec = 1,
 652                         .tv_usec = 0
 653                 },
 654                 .select_function = server_select
 655         };
 656         server_init(argc, argv);
 657         mutex_lock(mmd_mutex);
 658         ret = schedule(&s);
 659         if (ret < 0) {
 660                 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
 661                 exit(EXIT_FAILURE);
 662         }
 663         exit(EXIT_SUCCESS);
 664 }