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"
56 #include "close_on_fork.h"
61 #include "user_list.h"
65 /** Array of error strings. */
68 __printf_2_3 void (*para_log)(int, const char*, ...) = daemon_log;
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 active value for all config options of para_server.
82 * It is computed by merging the parse result of the command line options with
83 * the parse result of the config file.
85 struct lls_parse_result *server_lpr = NULL;
87 /* Command line options (no config file options). Used in handle_sighup(). */
88 static struct lls_parse_result *cmdline_lpr;
91 * A random number used to "authenticate" the afs connection.
93 * para_server picks this number by random before it forks the afs process. The
94 * command handlers know this number as well and write it to the afs socket,
95 * together with the id of the shared memory area which contains the payload of
96 * the afs command. A local process has to know this number to abuse the afs
97 * service provided by the local socket.
99 uint32_t afs_socket_cookie;
101 /** The mutex protecting the shared memory area containing the mmd struct. */
104 /* Serializes log output. */
105 static int log_mutex;
107 static struct sched sched;
108 static struct signal_task *signal_task;
110 /** The process id of the audio file selector process. */
113 /* The main server process (parent of afs and the command handlers). */
114 static pid_t server_pid;
117 * Tell whether the executing process is a command handler.
119 * Cleanup on exit must be performed differently for command handlers.
121 * \return True if the pid of the executing process is neither the server pid
124 bool process_is_command_handler(void)
126 pid_t pid = getpid();
128 return pid != afs_pid && pid != server_pid;
131 /** The task responsible for server command handling. */
132 struct server_command_task {
133 unsigned num_listen_fds; /* only one by default */
134 /** TCP socket(s) on which para_server listens for connections. */
136 /* File descriptor for the accepted socket. */
138 /** Copied from para_server's main function. */
140 /** Argument vector passed to para_server's main function. */
142 /** The command task structure for scheduling. */
147 * Return the list of tasks for the server process.
149 * This is called from \a com_tasks(). The helper is necessary since command
150 * handlers can not access the scheduler structure directly.
152 * \return A dynamically allocated string that must be freed by the caller.
154 char *server_get_tasks(void)
156 return get_task_list(&sched);
159 static void pre_log_hook(void)
161 mutex_lock(log_mutex);
164 static void post_log_hook(void)
166 mutex_unlock(log_mutex);
169 /* Setup shared memory area and init mutexes */
170 static void init_ipc_or_die(void)
173 int shmid, ret = shm_new(sizeof(struct misc_meta_data));
178 ret = shm_attach(shmid, ATTACH_RW, &shm);
190 goto destroy_mmd_mutex;
194 mmd->num_commands = 0;
196 mmd->num_connects = 0;
197 mmd->active_connections = 0;
198 mmd->vss_status_flags = VSS_NEXT;
199 mmd->new_vss_status_flags = VSS_NEXT;
202 mutex_destroy(mmd_mutex);
204 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
209 * (Re-)read the server configuration files.
211 * \param reload Whether config file overrides command line.
213 * This function also re-opens the logfile and the user list. On SIGHUP it is
214 * called from both server and afs context.
216 void parse_config_or_die(bool reload)
219 unsigned flags = MCF_DONT_FREE;
221 if (server_lpr != cmdline_lpr)
222 lls_free_parse_result(server_lpr, CMD_PTR);
223 server_lpr = cmdline_lpr;
225 flags |= MCF_OVERRIDE;
226 ret = lsu_merge_config_file_options(OPT_STRING_VAL(CONFIG_FILE),
227 "server.conf", &server_lpr, CMD_PTR, server_suite, flags);
229 PARA_EMERG_LOG("failed to parse config file: %s\n",
230 para_strerror(-ret));
233 daemon_set_loglevel(ENUM_STRING_VAL(LOGLEVEL));
234 if (OPT_GIVEN(LOGFILE)) {
235 daemon_set_logfile(OPT_STRING_VAL(LOGFILE));
236 daemon_open_log_or_die();
238 if (daemon_init_colors_or_die(OPT_UINT32_VAL(COLOR), COLOR_AUTO,
239 COLOR_NO, OPT_GIVEN(LOGFILE))) {
241 for (i = 0; i < OPT_GIVEN(LOG_COLOR); i++)
242 daemon_set_log_color_or_die(lls_string_val(i,
243 OPT_RESULT(LOG_COLOR)));
245 daemon_set_flag(DF_LOG_PID);
246 daemon_set_flag(DF_LOG_LL);
247 daemon_set_flag(DF_LOG_TIME);
248 if (OPT_GIVEN(LOG_TIMING))
249 daemon_set_flag(DF_LOG_TIMING);
250 daemon_set_priority(OPT_UINT32_VAL(PRIORITY));
251 if (!reload || getpid() != afs_pid) {
252 char *user_list_file;
253 if (OPT_GIVEN(USER_LIST))
254 user_list_file = para_strdup(OPT_STRING_VAL(USER_LIST));
256 char *home = para_homedir();
257 user_list_file = make_message("%s/.paraslash/server.users", home);
260 user_list_init(user_list_file);
261 free(user_list_file);
267 * called when server gets SIGHUP or when client invokes hup command.
269 static void handle_sighup(void)
272 PARA_NOTICE_LOG("SIGHUP\n");
273 parse_config_or_die(true);
275 kill(afs_pid, SIGHUP);
278 static int signal_post_select(struct sched *s, __a_unused void *context)
282 ret = task_get_notification(signal_task->task);
285 signum = para_next_signal(&s->rfds);
295 ret = para_reap_child(&pid);
300 PARA_EMERG_LOG("fatal: afs died\n");
304 /* die on sigint/sigterm. Kill all children too. */
307 PARA_EMERG_LOG("terminating on signal %d\n", signum);
311 * We must wait for all of our children to die. For the afs
312 * process or a command handler might want to use the
313 * shared memory area and the mmd mutex. If we destroy this
314 * mutex too early and afs tries to lock the shared memory
315 * area, the call to mutex_lock() will fail and terminate the
316 * afs process. This leads to dirty osl tables.
318 PARA_INFO_LOG("waiting for child processes to die\n");
319 mutex_unlock(mmd_mutex);
320 while (wait(NULL) != -1 || errno != ECHILD)
321 ; /* still at least one child alive */
322 mutex_lock(mmd_mutex);
323 free(mmd->afd.afhi.chunk_table);
324 task_notify_all(s, E_DEADLY_SIGNAL);
325 return -E_DEADLY_SIGNAL;
330 static void init_signal_task(void)
332 signal_task = signal_init_or_die();
333 para_install_sighandler(SIGINT);
334 para_install_sighandler(SIGTERM);
335 para_install_sighandler(SIGHUP);
336 para_install_sighandler(SIGCHLD);
337 para_sigaction(SIGPIPE, SIG_IGN);
338 add_close_on_fork_list(signal_task->fd);
339 signal_task->task = task_register(&(struct task_info) {
341 .pre_select = signal_pre_select,
342 .post_select = signal_post_select,
343 .context = signal_task,
348 static void command_pre_select(struct sched *s, void *context)
351 struct server_command_task *sct = context;
353 for (n = 0; n < sct->num_listen_fds; n++)
354 para_fd_set(sct->listen_fds[n], &s->rfds, &s->max_fileno);
357 static int command_task_accept(unsigned listen_idx, struct sched *s,
358 struct server_command_task *sct)
363 uint32_t *chunk_table;
365 ret = para_accept(sct->listen_fds[listen_idx], &s->rfds, NULL, 0, &new_fd);
369 mmd->active_connections++;
371 * The chunk table is a pointer located in the mmd struct that points
372 * to dynamically allocated memory, i.e. it must be freed by the parent
373 * and the child. However, as the mmd struct is in a shared memory
374 * area, there's no guarantee that after the fork this pointer is still
375 * valid in child context. As it is not used in the child anyway, we
376 * save it to a local variable before the fork and free the memory via
377 * that copy in the child directly after the fork.
379 chunk_table = mmd->afd.afhi.chunk_table;
382 ret = -ERRNO_TO_PARA_ERROR(errno);
386 /* avoid problems with non-fork-safe PRNGs */
387 unsigned char buf[16];
388 get_random_bytes_or_die(buf, sizeof(buf));
390 /* parent keeps accepting connections */
393 peer_name = remote_name(new_fd);
394 PARA_INFO_LOG("accepted connection from %s\n", peer_name);
395 /* mmd might already have changed at this point */
397 sct->child_fd = new_fd;
399 * put info on who we are serving into argv[0] to make
400 * client ip visible in top/ps
402 for (i = sct->argc - 1; i >= 0; i--)
403 memset(sct->argv[i], 0, strlen(sct->argv[i]));
404 i = sct->argc - 1 - lls_num_inputs(cmdline_lpr);
405 sprintf(sct->argv[i], "para_server (serving %s)", peer_name);
406 /* ask other tasks to terminate */
407 task_notify_all(s, E_CHILD_CONTEXT);
409 * After we return, the scheduler calls server_select() with a minimal
410 * timeout value, because the remaining tasks have a notification
411 * pending. Next it calls the ->post_select method of these tasks,
412 * which will return negative in view of the notification. This causes
413 * schedule() to return as there are no more runnable tasks.
415 * Note that semaphores are not inherited across a fork(), so we don't
416 * hold the lock at this point. Since server_select() drops the lock
417 * prior to calling para_select(), we need to acquire it here.
419 mutex_lock(mmd_mutex);
420 return -E_CHILD_CONTEXT;
423 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
427 static int command_post_select(struct sched *s, void *context)
429 struct server_command_task *sct = context;
433 ret = task_get_notification(sct->task);
436 for (n = 0; n < sct->num_listen_fds; n++) {
437 ret = command_task_accept(n, s, sct);
439 free(sct->listen_fds);
446 static void init_server_command_task(struct server_command_task *sct,
447 int argc, char **argv)
451 uint32_t port = OPT_UINT32_VAL(PORT);
453 PARA_NOTICE_LOG("initializing tcp command socket\n");
457 if (!OPT_GIVEN(LISTEN_ADDRESS)) {
458 sct->num_listen_fds = 1;
459 sct->listen_fds = para_malloc(sizeof(int));
460 ret = para_listen_simple(IPPROTO_TCP, port);
463 sct->listen_fds[0] = ret;
465 sct->num_listen_fds = OPT_GIVEN(LISTEN_ADDRESS);
466 sct->listen_fds = para_malloc(sct->num_listen_fds * sizeof(int));
467 for (n = 0; n < OPT_GIVEN(LISTEN_ADDRESS); n++) {
469 arg = lls_string_val(n, OPT_RESULT(LISTEN_ADDRESS));
470 ret = para_listen(IPPROTO_TCP, arg, port);
473 sct->listen_fds[n] = ret;
476 for (n = 0; n < sct->num_listen_fds; n++) {
477 ret = mark_fd_nonblocking(sct->listen_fds[n]);
480 /* child doesn't need the listener */
481 add_close_on_fork_list(sct->listen_fds[n]);
484 sct->task = task_register(&(struct task_info) {
485 .name = "server command",
486 .pre_select = command_pre_select,
487 .post_select = command_post_select,
491 * Detect whether the abstract Unix domain socket space is supported,
492 * but do not create the socket. We check this once in server context
493 * so that the command handlers inherit this bit of information and
494 * don't need to check again.
496 create_local_socket(NULL);
499 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
503 static int init_afs(int argc, char **argv)
505 int ret, afs_server_socket[2];
508 ret = socketpair(PF_UNIX, SOCK_STREAM, 0, afs_server_socket);
511 get_random_bytes_or_die((unsigned char *)&afs_socket_cookie,
512 sizeof(afs_socket_cookie));
516 if (afs_pid == 0) { /* child (afs) */
522 for (i = argc - 1; i >= 0; i--)
523 memset(argv[i], 0, strlen(argv[i]));
524 i = argc - lls_num_inputs(cmdline_lpr) - 1;
525 sprintf(argv[i], "para_server (afs)");
526 close(afs_server_socket[0]);
527 afs_init(afs_server_socket[1]);
529 close(afs_server_socket[1]);
530 if (read(afs_server_socket[0], &c, 1) <= 0) {
531 PARA_EMERG_LOG("early afs exit\n");
534 ret = mark_fd_nonblocking(afs_server_socket[0]);
537 add_close_on_fork_list(afs_server_socket[0]);
538 PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
539 afs_server_socket[0], (unsigned) afs_socket_cookie);
540 return afs_server_socket[0];
543 static void handle_help_flags(void)
546 bool d = OPT_GIVEN(DETAILED_HELP);
549 help = lls_long_help(CMD_PTR);
550 else if (OPT_GIVEN(HELP))
551 help = lls_short_help(CMD_PTR);
554 printf("%s\n", help);
559 static void server_init(int argc, char **argv, struct server_command_task *sct)
561 int ret, afs_socket, daemon_pipe = -1;
565 /* parse command line options */
566 ret = lls(lls_parse(argc, argv, CMD_PTR, &cmdline_lpr, &errctx));
569 server_lpr = cmdline_lpr;
570 daemon_set_loglevel(ENUM_STRING_VAL(LOGLEVEL));
571 daemon_drop_privileges_or_die(OPT_STRING_VAL(USER),
572 OPT_STRING_VAL(GROUP));
573 version_handle_flag("server", OPT_GIVEN(VERSION));
575 parse_config_or_die(false);
577 if (OPT_GIVEN(DAEMON))
578 daemon_pipe = daemonize(true /* parent waits for SIGTERM */);
579 server_pid = getpid();
581 daemon_log_welcome("server");
582 init_ipc_or_die(); /* init mmd struct, mmd and log mutex */
583 daemon_set_start_time();
584 daemon_set_hooks(pre_log_hook, post_log_hook);
586 * Although afs uses its own signal handling we must ignore SIGUSR1
587 * _before_ the afs child process gets born by init_afs() below. It's
588 * racy to do this in the child because the parent might send SIGUSR1
589 * before the child gets a chance to ignore this signal.
591 * We also have to block SIGCHLD before the afs process is created
592 * because otherwise para_server does not notice if afs dies before the
593 * SIGCHLD handler has been installed for the parent process by
594 * init_signal_task() below.
596 para_sigaction(SIGUSR1, SIG_IGN);
597 para_block_signal(SIGCHLD);
598 PARA_NOTICE_LOG("initializing the audio file selector\n");
599 afs_socket = init_afs(argc, argv);
601 para_unblock_signal(SIGCHLD);
602 PARA_NOTICE_LOG("initializing virtual streaming system\n");
603 vss_init(afs_socket, &sched);
604 init_server_command_task(sct, argc, argv);
605 if (daemon_pipe >= 0) {
606 if (write(daemon_pipe, "\0", 1) < 0) {
607 PARA_EMERG_LOG("daemon_pipe: %s", strerror(errno));
612 PARA_NOTICE_LOG("server init complete\n");
617 PARA_ERROR_LOG("%s\n", errctx);
618 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
622 static void status_refresh(void)
624 static int prev_uptime = -1, prev_events = -1;
625 int uptime = daemon_get_uptime(now);
627 if (prev_events != mmd->events)
629 if (mmd->new_vss_status_flags != mmd->vss_status_flags)
631 if (uptime / 60 != prev_uptime / 60)
637 prev_uptime = uptime;
638 prev_events = mmd->events;
639 mmd->vss_status_flags = mmd->new_vss_status_flags;
640 PARA_DEBUG_LOG("%u events, forcing status update\n", mmd->events);
644 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
645 struct timeval *timeout_tv)
650 mutex_unlock(mmd_mutex);
651 ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
652 mutex_lock(mmd_mutex);
657 * Deallocate all lopsub parse results.
659 * The server allocates a parse result for command line options and optionally
660 * a second parse result for the effective configuration, defined by merging
661 * the command line options with the options stored in the configuration file.
662 * This function frees both structures.
666 lls_free_parse_result(server_lpr, CMD_PTR);
667 if (server_lpr != cmdline_lpr)
668 lls_free_parse_result(cmdline_lpr, CMD_PTR);
672 * The main function of para_server.
674 * \param argc Usual argument count.
675 * \param argv Usual argument vector.
677 * \return EXIT_SUCCESS or EXIT_FAILURE.
679 int main(int argc, char *argv[])
682 struct server_command_task server_command_task_struct,
683 *sct = &server_command_task_struct;
685 sched.default_timeout.tv_sec = 1;
686 sched.select_function = server_select;
688 server_init(argc, argv, sct);
689 mutex_lock(mmd_mutex);
690 ret = schedule(&sched);
692 * We hold the mmd lock: it was re-acquired in server_select()
693 * after the select call.
695 mutex_unlock(mmd_mutex);
696 sched_shutdown(&sched);
698 signal_shutdown(signal_task);
699 if (!process_is_command_handler()) { /* parent (server) */
700 mutex_destroy(mmd_mutex);
701 daemon_set_hooks(NULL, NULL); /* only one process remaining */
702 mutex_destroy(log_mutex);
703 deplete_close_on_fork_list();
705 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
707 alarm(ALARM_TIMEOUT);
709 ret = handle_connect(sct->child_fd);
715 exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);