2 * Copyright (C) 1997-2014 Andre Noll <maan@systemlinux.org>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file server.c Paraslash's main server. */
10 * \mainpage Main data structures:
12 * - Server: \ref server_command, \ref sender,
13 * - Audio file selector: \ref afs_info, \ref afs_table,
14 * - Audio format handler: \ref audio_format_handler, \ref afh_info
15 * - Receivers/filters/writers: \ref receiver, \ref receiver_node,
16 * \ref filter, \ref filter_node, \ref writer_node, \ref writer.
20 * - Scheduling: \ref sched.h,
21 * - Buffer trees: \ref buffer_tree.h,
22 * - Sideband API: \ref sideband.h,
23 * - Crypto: \ref crypt.h, \ref crypt_backend.h,
24 * - Error subsystem: \ref error.h, \ref error2.c,
25 * - Inter process communication: \ref ipc.h,
26 * - Forward error correction: \ref fec.h,
27 * - Daemons: \ref daemon.h,
28 * - Mixer API: \ref mix.h,
29 * - Interactive sessions: \ref interactive.h,
30 * - File descriptors: \ref fd.h,
31 * - Signals: \ref signal.h,
32 * - Networking: \ref net.h,
33 * - Time: \ref time.c,
34 * - Doubly linked lists: \ref list.h.
44 #include "server.cmdline.h"
54 #include "close_on_fork.h"
60 #include "user_list.h"
65 __printf_2_3 void (*para_log)(int, const char*, ...) = daemon_log;
67 /** Define the array of error lists needed by para_server. */
70 /** Shut down non-authorized connections after that many seconds. */
71 #define ALARM_TIMEOUT 10
74 * Pointer to shared memory area for communication between para_server
75 * and its children. Exported to vss.c. command.c and to afs.
77 struct misc_meta_data *mmd;
80 * The configuration of para_server
82 * It also contains the options for the audio file selector, audio format
83 * handler and all supported senders.
85 struct server_args_info conf;
87 /** A random value used in child context for authentication. */
88 uint32_t afs_socket_cookie;
90 /** The mutex protecting the shared memory area containing the mmd struct. */
93 /** The file containing user information (public key, permissions). */
94 static char *user_list_file = NULL;
96 static struct sched sched;
98 /** The task responsible for server command handling. */
99 struct server_command_task {
100 /** TCP port on which para_server listens for connections. */
102 /** Copied from para_server's main function. */
104 /** Argument vector passed to para_server's main function. */
106 /** The command task structure for scheduling. */
110 static int want_colors(void)
112 if (conf.color_arg == color_arg_no)
114 if (conf.color_arg == color_arg_yes)
116 if (conf.logfile_given)
118 return isatty(STDERR_FILENO);
121 static void init_colors_or_die(void)
127 daemon_set_flag(DF_COLOR_LOG);
128 daemon_set_default_log_colors();
129 for (i = 0; i < conf.log_color_given; i++)
130 daemon_set_log_color_or_die(conf.log_color_arg[i]);
134 * setup shared memory area and get mutex for locking
136 static void init_ipc_or_die(void)
139 int shmid, ret = shm_new(sizeof(struct misc_meta_data));
144 ret = shm_attach(shmid, ATTACH_RW, &shm);
156 mmd->num_commands = 0;
158 mmd->num_connects = 0;
159 mmd->active_connections = 0;
160 mmd->vss_status_flags = VSS_NEXT;
161 mmd->new_vss_status_flags = VSS_NEXT;
164 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
169 * (Re-)read the server configuration files.
171 * \param override Passed to gengetopt to activate the override feature.
173 * This function also re-opens the logfile and sets the global \a
174 * user_list_file variable.
176 void parse_config_or_die(int override)
178 char *home = para_homedir();
183 if (conf.config_file_given)
184 cf = para_strdup(conf.config_file_arg);
186 cf = make_message("%s/.paraslash/server.conf", home);
187 free(user_list_file);
188 if (!conf.user_list_given)
189 user_list_file = make_message("%s/.paraslash/server.users", home);
191 user_list_file = para_strdup(conf.user_list_arg);
192 ret = file_exists(cf);
193 if (conf.config_file_given && !ret) {
195 PARA_EMERG_LOG("can not read config file %s\n", cf);
199 int tmp = conf.daemon_given;
200 struct server_cmdline_parser_params params = {
201 .override = override,
204 .check_ambiguity = 0,
205 .print_errors = !conf.daemon_given
207 server_cmdline_parser_config_file(cf, &conf, ¶ms);
208 daemon_set_loglevel(conf.loglevel_arg);
209 conf.daemon_given = tmp;
211 if (conf.logfile_given) {
212 daemon_set_logfile(conf.logfile_arg);
213 daemon_open_log_or_die();
215 init_colors_or_die();
216 daemon_set_flag(DF_LOG_PID);
217 daemon_set_flag(DF_LOG_LL);
218 daemon_set_flag(DF_LOG_TIME);
219 if (conf.log_timing_given)
220 daemon_set_flag(DF_LOG_TIMING);
227 free(user_list_file);
228 user_list_file = NULL;
232 static void signal_pre_select(struct sched *s, struct task *t)
234 struct signal_task *st = container_of(t, struct signal_task, task);
235 para_fd_set(st->fd, &s->rfds, &s->max_fileno);
239 * called when server gets SIGHUP or when client invokes hup command.
241 static void handle_sighup(void)
243 PARA_NOTICE_LOG("SIGHUP\n");
244 parse_config_or_die(1); /* reopens log */
245 init_user_list(user_list_file); /* reload user list */
247 kill(mmd->afs_pid, SIGHUP);
250 static int signal_post_select(struct sched *s, __a_unused struct task *t)
252 int signum = para_next_signal(&s->rfds);
263 int ret = para_reap_child(&pid);
266 if (pid != mmd->afs_pid)
268 PARA_EMERG_LOG("fatal: afs died\n");
273 /* die on sigint/sigterm. Kill all children too. */
276 PARA_EMERG_LOG("terminating on signal %d\n", signum);
279 * We must wait for afs because afs catches SIGINT/SIGTERM.
280 * Before reacting to the signal, afs might want to use the
281 * shared memory area and the mmd mutex. If we destroy this
282 * mutex too early and afs tries to lock the shared memory
283 * area, the call to mutex_lock() will fail and terminate the
284 * afs process. This leads to dirty osl tables.
286 * There's no such problem with the other children of the
287 * server process (the command handlers) as these reset their
288 * SIGINT/SIGTERM handlers to the default action, i.e. these
289 * processes get killed immediately by the above kill().
291 PARA_INFO_LOG("waiting for afs (pid %d) to die\n",
293 waitpid(mmd->afs_pid, NULL, 0);
295 free(mmd->afd.afhi.chunk_table);
297 mutex_destroy(mmd_mutex);
304 static void init_signal_task(void)
306 static struct signal_task signal_task_struct,
307 *st = &signal_task_struct;
309 st->task.pre_select = signal_pre_select;
310 st->task.post_select = signal_post_select;
311 sprintf(st->task.status, "signal task");
313 PARA_NOTICE_LOG("setting up signal handling\n");
314 st->fd = para_signal_init(); /* always successful */
315 para_install_sighandler(SIGINT);
316 para_install_sighandler(SIGTERM);
317 para_install_sighandler(SIGHUP);
318 para_install_sighandler(SIGCHLD);
319 para_sigaction(SIGPIPE, SIG_IGN);
320 add_close_on_fork_list(st->fd);
321 register_task(&sched, &st->task);
324 static void command_pre_select(struct sched *s, struct task *t)
326 struct server_command_task *sct = container_of(t, struct server_command_task, task);
327 para_fd_set(sct->listen_fd, &s->rfds, &s->max_fileno);
330 static int command_post_select(struct sched *s, struct task *t)
332 struct server_command_task *sct = container_of(t, struct server_command_task, task);
337 uint32_t *chunk_table;
339 ret = para_accept(sct->listen_fd, &s->rfds, NULL, 0, &new_fd);
342 peer_name = remote_name(new_fd);
343 PARA_INFO_LOG("got connection from %s, forking\n", peer_name);
345 mmd->active_connections++;
347 * The chunk table is a pointer located in the mmd struct that points
348 * to dynamically allocated memory, i.e. it must be freed by the parent
349 * and the child. However, as the mmd struct is in a shared memory
350 * area, there's no guarantee that after the fork this pointer is still
351 * valid in child context. As it is not used in the child anyway, we
352 * save it to a local variable before the fork and free the memory via
353 * that copy in the child directly after the fork.
355 chunk_table = mmd->afd.afhi.chunk_table;
358 ret = -ERRNO_TO_PARA_ERROR(errno);
362 /* avoid problems with non-fork-safe PRNGs */
363 unsigned char buf[16];
364 get_random_bytes_or_die(buf, sizeof(buf));
366 /* parent keeps accepting connections */
369 /* mmd might already have changed at this point */
371 alarm(ALARM_TIMEOUT);
373 para_signal_shutdown();
375 * put info on who we are serving into argv[0] to make
376 * client ip visible in top/ps
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 handle_connect(new_fd, peer_name);
385 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
389 static void init_server_command_task(int argc, char **argv)
392 static struct server_command_task server_command_task_struct,
393 *sct = &server_command_task_struct;
395 PARA_NOTICE_LOG("initializing tcp command socket\n");
396 sct->task.pre_select = command_pre_select;
397 sct->task.post_select = command_post_select;
400 ret = para_listen_simple(IPPROTO_TCP, conf.port_arg);
403 sct->listen_fd = ret;
404 ret = mark_fd_nonblocking(sct->listen_fd);
407 add_close_on_fork_list(sct->listen_fd); /* child doesn't need the listener */
408 sprintf(sct->task.status, "server command task");
409 register_task(&sched, &sct->task);
412 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
416 static int init_afs(int argc, char **argv)
418 int ret, afs_server_socket[2];
421 ret = socketpair(PF_UNIX, SOCK_DGRAM, 0, afs_server_socket);
424 get_random_bytes_or_die((unsigned char *)&afs_socket_cookie,
425 sizeof(afs_socket_cookie));
429 if (afs_pid == 0) { /* child (afs) */
431 for (i = argc - 1; i >= 0; i--)
432 memset(argv[i], 0, strlen(argv[i]));
433 sprintf(argv[0], "para_server (afs)");
434 close(afs_server_socket[0]);
435 afs_init(afs_socket_cookie, afs_server_socket[1]);
437 mmd->afs_pid = afs_pid;
438 close(afs_server_socket[1]);
439 ret = mark_fd_nonblocking(afs_server_socket[0]);
442 add_close_on_fork_list(afs_server_socket[0]);
443 PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
444 afs_server_socket[0], (unsigned) afs_socket_cookie);
445 return afs_server_socket[0];
448 __noreturn static void print_help_and_die(void)
450 struct ggo_help h = DEFINE_GGO_HELP(server);
451 bool d = conf.detailed_help_given;
453 ggo_print_help(&h, d? GPH_STANDARD_FLAGS_DETAILED : GPH_STANDARD_FLAGS);
457 static void server_init(int argc, char **argv)
459 struct server_cmdline_parser_params params = {
463 .check_ambiguity = 0,
469 init_random_seed_or_die();
470 /* parse command line options */
471 server_cmdline_parser_ext(argc, argv, &conf, ¶ms);
472 daemon_set_loglevel(conf.loglevel_arg);
473 version_handle_flag("server", conf.version_given);
474 if (conf.help_given || conf.detailed_help_given)
475 print_help_and_die();
476 drop_privileges_or_die(conf.user_arg, conf.group_arg);
477 /* parse config file, open log and set defaults */
478 parse_config_or_die(0);
479 log_welcome("para_server");
480 init_ipc_or_die(); /* init mmd struct and mmd->lock */
481 /* make sure, the global now pointer is uptodate */
482 clock_get_realtime(now);
483 set_server_start_time(now);
484 init_user_list(user_list_file);
486 if (conf.daemon_given)
487 daemonize(true /* parent waits for SIGTERM */);
488 PARA_NOTICE_LOG("initializing audio format handlers\n");
492 * Although afs uses its own signal handling we must ignore SIGUSR1
493 * _before_ the afs child process gets born by init_afs() below. It's
494 * racy to do this in the child because the parent might send SIGUSR1
495 * before the child gets a chance to ignore this signal -- only the
498 para_sigaction(SIGUSR1, SIG_IGN);
500 * We have to block SIGCHLD before the afs process is being forked off.
501 * Otherwise, para_server does not notice if afs dies before the
502 * SIGCHLD handler has been installed for the parent process by
503 * init_signal_task() below.
505 para_block_signal(SIGCHLD);
506 PARA_NOTICE_LOG("initializing the audio file selector\n");
507 afs_socket = init_afs(argc, argv);
509 para_unblock_signal(SIGCHLD);
510 PARA_NOTICE_LOG("initializing virtual streaming system\n");
511 init_vss_task(afs_socket, &sched);
512 init_server_command_task(argc, argv);
513 if (conf.daemon_given)
514 kill(getppid(), SIGTERM);
515 PARA_NOTICE_LOG("server init complete\n");
518 static void status_refresh(void)
520 static int prev_uptime = -1, prev_events = -1;
521 int uptime = get_server_uptime(now);
523 if (prev_events != mmd->events)
525 if (mmd->new_vss_status_flags != mmd->vss_status_flags)
527 if (uptime / 60 != prev_uptime / 60)
533 prev_uptime = uptime;
534 prev_events = mmd->events;
535 mmd->vss_status_flags = mmd->new_vss_status_flags;
536 PARA_DEBUG_LOG("%d events, forcing status update\n", mmd->events);
540 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
541 struct timeval *timeout_tv)
546 mutex_unlock(mmd_mutex);
547 ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
548 mutex_lock(mmd_mutex);
553 * The main function of para_server.
555 * \param argc Usual argument count.
556 * \param argv Usual argument vector.
558 * \return EXIT_SUCCESS or EXIT_FAILURE.
560 int main(int argc, char *argv[])
564 sched.default_timeout.tv_sec = 1;
565 sched.select_function = server_select;
567 server_init(argc, argv);
568 mutex_lock(mmd_mutex);
569 ret = schedule(&sched);
571 PARA_EMERG_LOG("%s\n", para_strerror(-ret));