1 /* Copyright (C) 1997 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
3 /** \file server.c Paraslash's main server. */
6 * \mainpage Main data structures and selected APIs:
8 * - Senders: \ref sender,
9 * - Audio file selector: \ref afs_info, \ref afs_table,
10 * - Audio format handler: \ref audio_format_handler, \ref afh_info
11 * - Receivers/filters/writers: \ref receiver, \ref receiver_node,
12 * \ref filter, \ref filter_node, \ref writer_node, \ref writer.
13 * - Scheduling: \ref sched.h,
14 * - Buffer trees: \ref buffer_tree.h,
15 * - Sideband API: \ref sideband.h,
16 * - Crypto: \ref crypt.h, \ref crypt_backend.h,
17 * - Error subsystem: \ref error.h,
18 * - Inter process communication: \ref ipc.h,
19 * - Forward error correction: \ref fec.h,
20 * - Daemons: \ref daemon.h,
21 * - Mixer API: \ref mix.h,
22 * - Interactive sessions: \ref interactive.h,
23 * - File descriptors: \ref fd.h,
24 * - Signals: \ref signal.h,
25 * - Networking: \ref net.h,
26 * - Time: \ref time.c,
27 * - Doubly linked lists: \ref list.h.
30 #include <netinet/in.h>
31 #include <sys/socket.h>
35 #include <sys/types.h>
36 #include <arpa/inet.h>
41 #include "server.lsg.h"
54 #include "close_on_fork.h"
60 #include "user_list.h"
64 /** Array of error strings. */
67 __printf_2_3 void (*para_log)(int, const char*, ...) = daemon_log;
69 /** Shut down non-authorized connections after that many seconds. */
70 #define ALARM_TIMEOUT 10
73 * Pointer to shared memory area for communication between para_server
74 * and its children. Exported to vss.c, command.c and to afs.
76 struct misc_meta_data *mmd;
79 * The active value for all config options of para_server.
81 * It is computed by merging the parse result of the command line options with
82 * the parse result of the config file.
84 struct lls_parse_result *server_lpr = NULL;
86 /* Command line options (no config file options). Used in handle_sighup(). */
87 static struct lls_parse_result *cmdline_lpr;
90 * A random number used to "authenticate" the afs connection.
92 * para_server picks this number by random before it forks the afs process. The
93 * command handlers know this number as well and write it to the afs socket,
94 * together with the id of the shared memory area which contains the payload of
95 * the afs command. A local process has to know this number to abuse the afs
96 * service provided by the local socket.
98 uint32_t afs_socket_cookie;
100 /** The mutex protecting the shared memory area containing the mmd struct. */
103 static struct sched sched;
104 static struct signal_task *signal_task;
106 /** The process id of the audio file selector process. */
109 /* The the main server process (parent of afs and the command handlers). */
110 static pid_t server_pid;
113 * Tell whether the executing process is a command handler.
115 * Cleanup on exit must be performed differently for command handlers.
117 * \return True if the pid of the executing process is neither the server pid
120 bool process_is_command_handler(void)
122 pid_t pid = getpid();
124 return pid != afs_pid && pid != server_pid;
127 /** The task responsible for server command handling. */
128 struct server_command_task {
129 /** TCP port on which para_server listens for connections. */
131 /* File descriptor for the accepted socket. */
133 /** Copied from para_server's main function. */
135 /** Argument vector passed to para_server's main function. */
137 /** The command task structure for scheduling. */
142 * Return the list of tasks for the server process.
144 * This is called from \a com_tasks(). The helper is necessary since command
145 * handlers can not access the scheduler structure directly.
147 * \return A dynamically allocated string that must be freed by the caller.
149 char *server_get_tasks(void)
151 return get_task_list(&sched);
155 * setup shared memory area and get mutex for locking
157 static void init_ipc_or_die(void)
160 int shmid, ret = shm_new(sizeof(struct misc_meta_data));
165 ret = shm_attach(shmid, ATTACH_RW, &shm);
177 mmd->num_commands = 0;
179 mmd->num_connects = 0;
180 mmd->active_connections = 0;
181 mmd->vss_status_flags = VSS_NEXT;
182 mmd->new_vss_status_flags = VSS_NEXT;
185 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
190 * (Re-)read the server configuration files.
192 * \param reload Whether config file overrides command line.
194 * This function also re-opens the logfile and the user list. On SIGHUP it is
195 * called from both server and afs context.
197 void parse_config_or_die(bool reload)
200 char *cf = NULL, *errctx = NULL, *user_list_file = NULL;
205 struct lls_parse_result *cf_lpr, *merged_lpr;
206 char *home = para_homedir();
208 if (OPT_GIVEN(CONFIG_FILE))
209 cf = para_strdup(OPT_STRING_VAL(CONFIG_FILE));
211 cf = make_message("%s/.paraslash/server.conf", home);
212 if (!mmd || getpid() != afs_pid) {
213 if (OPT_GIVEN(USER_LIST))
214 user_list_file = para_strdup(OPT_STRING_VAL(USER_LIST));
216 user_list_file = make_message("%s/.paraslash/server.users", home);
219 ret = mmap_full_file(cf, O_RDONLY, &map, &sz, NULL);
221 if (ret != -E_EMPTY && ret != -ERRNO_TO_PARA_ERROR(ENOENT))
223 if (ret == -ERRNO_TO_PARA_ERROR(ENOENT) && OPT_GIVEN(CONFIG_FILE))
225 server_lpr = cmdline_lpr;
228 ret = lls(lls_convert_config(map, sz, NULL, &cf_argv, &errctx));
229 para_munmap(map, sz);
233 ret = lls(lls_parse(cf_argc, cf_argv, CMD_PTR, &cf_lpr, &errctx));
234 lls_free_argv(cf_argv);
237 if (reload) /* config file overrides command line */
238 ret = lls(lls_merge(cf_lpr, cmdline_lpr, CMD_PTR, &merged_lpr,
240 else /* command line options override config file options */
241 ret = lls(lls_merge(cmdline_lpr, cf_lpr, CMD_PTR, &merged_lpr,
243 lls_free_parse_result(cf_lpr, CMD_PTR);
246 if (server_lpr != cmdline_lpr)
247 lls_free_parse_result(server_lpr, CMD_PTR);
248 server_lpr = merged_lpr;
250 daemon_set_loglevel(ENUM_STRING_VAL(LOGLEVEL));
251 if (OPT_GIVEN(LOGFILE)) {
252 daemon_set_logfile(OPT_STRING_VAL(LOGFILE));
253 daemon_open_log_or_die();
255 if (daemon_init_colors_or_die(OPT_UINT32_VAL(COLOR), COLOR_AUTO,
256 COLOR_NO, OPT_GIVEN(LOGFILE))) {
258 for (i = 0; i < OPT_GIVEN(LOG_COLOR); i++)
259 daemon_set_log_color_or_die(lls_string_val(i,
260 OPT_RESULT(LOG_COLOR)));
262 daemon_set_flag(DF_LOG_PID);
263 daemon_set_flag(DF_LOG_LL);
264 daemon_set_flag(DF_LOG_TIME);
265 if (OPT_GIVEN(LOG_TIMING))
266 daemon_set_flag(DF_LOG_TIMING);
267 daemon_set_priority(OPT_UINT32_VAL(PRIORITY));
269 init_user_list(user_list_file);
273 free(user_list_file);
276 PARA_ERROR_LOG("%s\n", errctx);
278 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
284 * called when server gets SIGHUP or when client invokes hup command.
286 static void handle_sighup(void)
289 PARA_NOTICE_LOG("SIGHUP\n");
290 parse_config_or_die(true);
292 kill(afs_pid, SIGHUP);
295 static int signal_post_select(struct sched *s, __a_unused void *context)
299 ret = task_get_notification(signal_task->task);
302 signum = para_next_signal(&s->rfds);
312 ret = para_reap_child(&pid);
317 PARA_EMERG_LOG("fatal: afs died\n");
322 /* die on sigint/sigterm. Kill all children too. */
325 PARA_EMERG_LOG("terminating on signal %d\n", signum);
328 * We must wait for afs because afs catches SIGINT/SIGTERM.
329 * Before reacting to the signal, afs might want to use the
330 * shared memory area and the mmd mutex. If we destroy this
331 * mutex too early and afs tries to lock the shared memory
332 * area, the call to mutex_lock() will fail and terminate the
333 * afs process. This leads to dirty osl tables.
335 * There's no such problem with the other children of the
336 * server process (the command handlers) as these reset their
337 * SIGINT/SIGTERM handlers to the default action, i.e. these
338 * processes get killed immediately by the above kill().
340 PARA_INFO_LOG("waiting for afs (pid %d) to die\n",
342 waitpid(afs_pid, NULL, 0);
344 free(mmd->afd.afhi.chunk_table);
346 mutex_destroy(mmd_mutex);
353 static void init_signal_task(void)
355 signal_task = signal_init_or_die();
356 para_install_sighandler(SIGINT);
357 para_install_sighandler(SIGTERM);
358 para_install_sighandler(SIGHUP);
359 para_install_sighandler(SIGCHLD);
360 para_sigaction(SIGPIPE, SIG_IGN);
361 add_close_on_fork_list(signal_task->fd);
362 signal_task->task = task_register(&(struct task_info) {
364 .pre_select = signal_pre_select,
365 .post_select = signal_post_select,
366 .context = signal_task,
371 static void command_pre_select(struct sched *s, void *context)
373 struct server_command_task *sct = context;
374 para_fd_set(sct->listen_fd, &s->rfds, &s->max_fileno);
377 static int command_post_select(struct sched *s, void *context)
379 struct server_command_task *sct = context;
383 uint32_t *chunk_table;
385 ret = task_get_notification(sct->task);
388 ret = para_accept(sct->listen_fd, &s->rfds, NULL, 0, &new_fd);
392 mmd->active_connections++;
394 * The chunk table is a pointer located in the mmd struct that points
395 * to dynamically allocated memory, i.e. it must be freed by the parent
396 * and the child. However, as the mmd struct is in a shared memory
397 * area, there's no guarantee that after the fork this pointer is still
398 * valid in child context. As it is not used in the child anyway, we
399 * save it to a local variable before the fork and free the memory via
400 * that copy in the child directly after the fork.
402 chunk_table = mmd->afd.afhi.chunk_table;
405 ret = -ERRNO_TO_PARA_ERROR(errno);
409 /* avoid problems with non-fork-safe PRNGs */
410 unsigned char buf[16];
411 get_random_bytes_or_die(buf, sizeof(buf));
413 /* parent keeps accepting connections */
416 peer_name = remote_name(new_fd);
417 PARA_INFO_LOG("accepted connection from %s\n", peer_name);
418 /* mmd might already have changed at this point */
420 sct->child_fd = new_fd;
422 * put info on who we are serving into argv[0] to make
423 * client ip visible in top/ps
425 for (i = sct->argc - 1; i >= 0; i--)
426 memset(sct->argv[i], 0, strlen(sct->argv[i]));
427 i = sct->argc - 1 - lls_num_inputs(cmdline_lpr);
428 sprintf(sct->argv[i], "para_server (serving %s)", peer_name);
429 /* ask other tasks to terminate */
430 task_notify_all(s, E_CHILD_CONTEXT);
432 * After we return, the scheduler calls server_select() with a minimal
433 * timeout value, because the remaining tasks have a notification
434 * pending. Next it calls the ->post_select method of these tasks,
435 * which will return negative in view of the notification. This causes
436 * schedule() to return as there are no more runnable tasks.
438 * Note that semaphores are not inherited across a fork(), so we don't
439 * hold the lock at this point. Since server_select() drops the lock
440 * prior to calling para_select(), we need to acquire it here.
442 mutex_lock(mmd_mutex);
443 return -E_CHILD_CONTEXT;
446 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
450 static void init_server_command_task(struct server_command_task *sct,
451 int argc, char **argv)
455 PARA_NOTICE_LOG("initializing tcp command socket\n");
459 ret = para_listen_simple(IPPROTO_TCP, OPT_UINT32_VAL(PORT));
462 sct->listen_fd = ret;
463 ret = mark_fd_nonblocking(sct->listen_fd);
466 add_close_on_fork_list(sct->listen_fd); /* child doesn't need the listener */
467 sct->task = task_register(&(struct task_info) {
468 .name = "server command",
469 .pre_select = command_pre_select,
470 .post_select = command_post_select,
475 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
479 static int init_afs(int argc, char **argv)
481 int ret, afs_server_socket[2];
484 ret = socketpair(PF_UNIX, SOCK_STREAM, 0, afs_server_socket);
487 get_random_bytes_or_die((unsigned char *)&afs_socket_cookie,
488 sizeof(afs_socket_cookie));
492 if (afs_pid == 0) { /* child (afs) */
496 for (i = argc - 1; i >= 0; i--)
497 memset(argv[i], 0, strlen(argv[i]));
498 i = argc - lls_num_inputs(cmdline_lpr) - 1;
499 sprintf(argv[i], "para_server (afs)");
500 close(afs_server_socket[0]);
501 afs_init(afs_server_socket[1]);
503 close(afs_server_socket[1]);
504 if (read(afs_server_socket[0], &c, 1) <= 0) {
505 PARA_EMERG_LOG("early afs exit\n");
508 ret = mark_fd_nonblocking(afs_server_socket[0]);
511 add_close_on_fork_list(afs_server_socket[0]);
512 PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
513 afs_server_socket[0], (unsigned) afs_socket_cookie);
514 return afs_server_socket[0];
517 static void handle_help_flags(void)
520 bool d = OPT_GIVEN(DETAILED_HELP);
523 help = lls_long_help(CMD_PTR);
524 else if (OPT_GIVEN(HELP))
525 help = lls_short_help(CMD_PTR);
528 printf("%s\n", help);
533 static void server_init(int argc, char **argv, struct server_command_task *sct)
535 int ret, afs_socket, daemon_pipe = -1;
539 /* parse command line options */
540 ret = lls(lls_parse(argc, argv, CMD_PTR, &cmdline_lpr, &errctx));
543 server_lpr = cmdline_lpr;
544 daemon_set_loglevel(ENUM_STRING_VAL(LOGLEVEL));
545 daemon_drop_privileges_or_die(OPT_STRING_VAL(USER),
546 OPT_STRING_VAL(GROUP));
547 version_handle_flag("server", OPT_GIVEN(VERSION));
549 parse_config_or_die(false);
551 if (OPT_GIVEN(DAEMON))
552 daemon_pipe = daemonize(true /* parent waits for SIGTERM */);
553 server_pid = getpid();
554 init_random_seed_or_die();
555 daemon_log_welcome("server");
556 init_ipc_or_die(); /* init mmd struct and mmd->lock */
557 daemon_set_start_time();
558 PARA_NOTICE_LOG("initializing audio format handlers\n");
562 * Although afs uses its own signal handling we must ignore SIGUSR1
563 * _before_ the afs child process gets born by init_afs() below. It's
564 * racy to do this in the child because the parent might send SIGUSR1
565 * before the child gets a chance to ignore this signal.
567 * We also have to block SIGCHLD before the afs process is created
568 * because otherwise para_server does not notice if afs dies before the
569 * SIGCHLD handler has been installed for the parent process by
570 * init_signal_task() below.
572 para_sigaction(SIGUSR1, SIG_IGN);
573 para_block_signal(SIGCHLD);
574 PARA_NOTICE_LOG("initializing the audio file selector\n");
575 afs_socket = init_afs(argc, argv);
577 para_unblock_signal(SIGCHLD);
578 PARA_NOTICE_LOG("initializing virtual streaming system\n");
579 vss_init(afs_socket, &sched);
580 init_server_command_task(sct, argc, argv);
581 if (daemon_pipe >= 0) {
582 if (write(daemon_pipe, "\0", 1) < 0) {
583 PARA_EMERG_LOG("daemon_pipe: %s", strerror(errno));
588 PARA_NOTICE_LOG("server init complete\n");
593 PARA_ERROR_LOG("%s\n", errctx);
594 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
598 static void status_refresh(void)
600 static int prev_uptime = -1, prev_events = -1;
601 int uptime = daemon_get_uptime(now);
603 if (prev_events != mmd->events)
605 if (mmd->new_vss_status_flags != mmd->vss_status_flags)
607 if (uptime / 60 != prev_uptime / 60)
613 prev_uptime = uptime;
614 prev_events = mmd->events;
615 mmd->vss_status_flags = mmd->new_vss_status_flags;
616 PARA_DEBUG_LOG("%u events, forcing status update\n", mmd->events);
620 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
621 struct timeval *timeout_tv)
626 mutex_unlock(mmd_mutex);
627 ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
628 mutex_lock(mmd_mutex);
633 * The main function of para_server.
635 * \param argc Usual argument count.
636 * \param argv Usual argument vector.
638 * \return EXIT_SUCCESS or EXIT_FAILURE.
640 int main(int argc, char *argv[])
643 struct server_command_task server_command_task_struct,
644 *sct = &server_command_task_struct;
646 sched.default_timeout.tv_sec = 1;
647 sched.select_function = server_select;
649 server_init(argc, argv, sct);
650 mutex_lock(mmd_mutex);
651 ret = schedule(&sched);
652 sched_shutdown(&sched);
653 signal_shutdown(signal_task);
654 if (!process_is_command_handler()) { /* parent (server) */
656 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
659 * We hold the mmd lock: it was re-acquired in server_select()
660 * after the select call.
662 mutex_unlock(mmd_mutex);
663 alarm(ALARM_TIMEOUT);
665 ret = handle_connect(sct->child_fd);
668 lls_free_parse_result(server_lpr, CMD_PTR);
669 if (server_lpr != cmdline_lpr)
670 lls_free_parse_result(cmdline_lpr, CMD_PTR);
671 exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);