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"
55 #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 /* Serializes log output. */
104 static int log_mutex;
106 static struct sched sched;
107 static struct signal_task *signal_task;
109 /** The process id of the audio file selector process. */
112 /* The the main server process (parent of afs and the command handlers). */
113 static pid_t server_pid;
116 * Tell whether the executing process is a command handler.
118 * Cleanup on exit must be performed differently for command handlers.
120 * \return True if the pid of the executing process is neither the server pid
123 bool process_is_command_handler(void)
125 pid_t pid = getpid();
127 return pid != afs_pid && pid != server_pid;
130 /** The task responsible for server command handling. */
131 struct server_command_task {
132 unsigned num_listen_fds; /* only one by default */
133 /** TCP socket(s) on which para_server listens for connections. */
135 /* File descriptor for the accepted socket. */
137 /** Copied from para_server's main function. */
139 /** Argument vector passed to para_server's main function. */
141 /** The command task structure for scheduling. */
146 * Return the list of tasks for the server process.
148 * This is called from \a com_tasks(). The helper is necessary since command
149 * handlers can not access the scheduler structure directly.
151 * \return A dynamically allocated string that must be freed by the caller.
153 char *server_get_tasks(void)
155 return get_task_list(&sched);
158 static void pre_log_hook(void)
160 mutex_lock(log_mutex);
163 static void post_log_hook(void)
165 mutex_unlock(log_mutex);
168 /* Setup shared memory area and init mutexes */
169 static void init_ipc_or_die(void)
172 int shmid, ret = shm_new(sizeof(struct misc_meta_data));
177 ret = shm_attach(shmid, ATTACH_RW, &shm);
189 goto destroy_mmd_mutex;
193 mmd->num_commands = 0;
195 mmd->num_connects = 0;
196 mmd->active_connections = 0;
197 mmd->vss_status_flags = VSS_NEXT;
198 mmd->new_vss_status_flags = VSS_NEXT;
201 mutex_destroy(mmd_mutex);
203 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
208 * (Re-)read the server configuration files.
210 * \param reload Whether config file overrides command line.
212 * This function also re-opens the logfile and the user list. On SIGHUP it is
213 * called from both server and afs context.
215 void parse_config_or_die(bool reload)
218 char *cf = NULL, *errctx = NULL, *user_list_file = NULL;
223 struct lls_parse_result *cf_lpr, *merged_lpr;
224 char *home = para_homedir();
226 if (OPT_GIVEN(CONFIG_FILE))
227 cf = para_strdup(OPT_STRING_VAL(CONFIG_FILE));
229 cf = make_message("%s/.paraslash/server.conf", home);
230 if (!mmd || getpid() != afs_pid) {
231 if (OPT_GIVEN(USER_LIST))
232 user_list_file = para_strdup(OPT_STRING_VAL(USER_LIST));
234 user_list_file = make_message("%s/.paraslash/server.users", home);
237 ret = mmap_full_file(cf, O_RDONLY, &map, &sz, NULL);
239 if (ret != -E_EMPTY && ret != -ERRNO_TO_PARA_ERROR(ENOENT))
241 if (ret == -ERRNO_TO_PARA_ERROR(ENOENT) && OPT_GIVEN(CONFIG_FILE))
243 server_lpr = cmdline_lpr;
246 ret = lls(lls_convert_config(map, sz, NULL, &cf_argv, &errctx));
247 para_munmap(map, sz);
251 ret = lls(lls_parse(cf_argc, cf_argv, CMD_PTR, &cf_lpr, &errctx));
252 lls_free_argv(cf_argv);
255 if (reload) /* config file overrides command line */
256 ret = lls(lls_merge(cf_lpr, cmdline_lpr, CMD_PTR, &merged_lpr,
258 else /* command line options override config file options */
259 ret = lls(lls_merge(cmdline_lpr, cf_lpr, CMD_PTR, &merged_lpr,
261 lls_free_parse_result(cf_lpr, CMD_PTR);
264 if (server_lpr != cmdline_lpr)
265 lls_free_parse_result(server_lpr, CMD_PTR);
266 server_lpr = merged_lpr;
268 daemon_set_loglevel(ENUM_STRING_VAL(LOGLEVEL));
269 if (OPT_GIVEN(LOGFILE)) {
270 daemon_set_logfile(OPT_STRING_VAL(LOGFILE));
271 daemon_open_log_or_die();
273 if (daemon_init_colors_or_die(OPT_UINT32_VAL(COLOR), COLOR_AUTO,
274 COLOR_NO, OPT_GIVEN(LOGFILE))) {
276 for (i = 0; i < OPT_GIVEN(LOG_COLOR); i++)
277 daemon_set_log_color_or_die(lls_string_val(i,
278 OPT_RESULT(LOG_COLOR)));
280 daemon_set_flag(DF_LOG_PID);
281 daemon_set_flag(DF_LOG_LL);
282 daemon_set_flag(DF_LOG_TIME);
283 if (OPT_GIVEN(LOG_TIMING))
284 daemon_set_flag(DF_LOG_TIMING);
285 daemon_set_priority(OPT_UINT32_VAL(PRIORITY));
287 user_list_init(user_list_file);
291 free(user_list_file);
294 PARA_ERROR_LOG("%s\n", errctx);
296 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
302 * called when server gets SIGHUP or when client invokes hup command.
304 static void handle_sighup(void)
307 PARA_NOTICE_LOG("SIGHUP\n");
308 parse_config_or_die(true);
310 kill(afs_pid, SIGHUP);
313 static int signal_post_select(struct sched *s, __a_unused void *context)
317 ret = task_get_notification(signal_task->task);
320 signum = para_next_signal(&s->rfds);
330 ret = para_reap_child(&pid);
335 PARA_EMERG_LOG("fatal: afs died\n");
340 /* die on sigint/sigterm. Kill all children too. */
343 PARA_EMERG_LOG("terminating on signal %d\n", signum);
346 * We must wait for all of our children to die. For the afs
347 * process or a command handler might want to use the
348 * shared memory area and the mmd mutex. If we destroy this
349 * mutex too early and afs tries to lock the shared memory
350 * area, the call to mutex_lock() will fail and terminate the
351 * afs process. This leads to dirty osl tables.
353 PARA_INFO_LOG("waiting for child processes to die\n");
354 mutex_unlock(mmd_mutex);
355 while (wait(NULL) != -1 || errno != ECHILD)
356 ; /* still at least one child alive */
357 mutex_lock(mmd_mutex);
359 free(mmd->afd.afhi.chunk_table);
360 task_notify_all(s, E_DEADLY_SIGNAL);
361 return -E_DEADLY_SIGNAL;
366 static void init_signal_task(void)
368 signal_task = signal_init_or_die();
369 para_install_sighandler(SIGINT);
370 para_install_sighandler(SIGTERM);
371 para_install_sighandler(SIGHUP);
372 para_install_sighandler(SIGCHLD);
373 para_sigaction(SIGPIPE, SIG_IGN);
374 add_close_on_fork_list(signal_task->fd);
375 signal_task->task = task_register(&(struct task_info) {
377 .pre_select = signal_pre_select,
378 .post_select = signal_post_select,
379 .context = signal_task,
384 static void command_pre_select(struct sched *s, void *context)
387 struct server_command_task *sct = context;
389 for (n = 0; n < sct->num_listen_fds; n++)
390 para_fd_set(sct->listen_fds[n], &s->rfds, &s->max_fileno);
393 static int command_task_accept(unsigned listen_idx, struct sched *s,
394 struct server_command_task *sct)
399 uint32_t *chunk_table;
401 ret = para_accept(sct->listen_fds[listen_idx], &s->rfds, NULL, 0, &new_fd);
405 mmd->active_connections++;
407 * The chunk table is a pointer located in the mmd struct that points
408 * to dynamically allocated memory, i.e. it must be freed by the parent
409 * and the child. However, as the mmd struct is in a shared memory
410 * area, there's no guarantee that after the fork this pointer is still
411 * valid in child context. As it is not used in the child anyway, we
412 * save it to a local variable before the fork and free the memory via
413 * that copy in the child directly after the fork.
415 chunk_table = mmd->afd.afhi.chunk_table;
418 ret = -ERRNO_TO_PARA_ERROR(errno);
422 /* avoid problems with non-fork-safe PRNGs */
423 unsigned char buf[16];
424 get_random_bytes_or_die(buf, sizeof(buf));
426 /* parent keeps accepting connections */
429 peer_name = remote_name(new_fd);
430 PARA_INFO_LOG("accepted connection from %s\n", peer_name);
431 /* mmd might already have changed at this point */
433 sct->child_fd = new_fd;
435 * put info on who we are serving into argv[0] to make
436 * client ip visible in top/ps
438 for (i = sct->argc - 1; i >= 0; i--)
439 memset(sct->argv[i], 0, strlen(sct->argv[i]));
440 i = sct->argc - 1 - lls_num_inputs(cmdline_lpr);
441 sprintf(sct->argv[i], "para_server (serving %s)", peer_name);
442 /* ask other tasks to terminate */
443 task_notify_all(s, E_CHILD_CONTEXT);
445 * After we return, the scheduler calls server_select() with a minimal
446 * timeout value, because the remaining tasks have a notification
447 * pending. Next it calls the ->post_select method of these tasks,
448 * which will return negative in view of the notification. This causes
449 * schedule() to return as there are no more runnable tasks.
451 * Note that semaphores are not inherited across a fork(), so we don't
452 * hold the lock at this point. Since server_select() drops the lock
453 * prior to calling para_select(), we need to acquire it here.
455 mutex_lock(mmd_mutex);
456 return -E_CHILD_CONTEXT;
459 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
463 static int command_post_select(struct sched *s, void *context)
465 struct server_command_task *sct = context;
469 ret = task_get_notification(sct->task);
472 for (n = 0; n < sct->num_listen_fds; n++) {
473 ret = command_task_accept(n, s, sct);
475 free(sct->listen_fds);
482 static void init_server_command_task(struct server_command_task *sct,
483 int argc, char **argv)
487 uint32_t port = OPT_UINT32_VAL(PORT);
489 PARA_NOTICE_LOG("initializing tcp command socket\n");
493 if (!OPT_GIVEN(LISTEN_ADDRESS)) {
494 sct->num_listen_fds = 1;
495 sct->listen_fds = para_malloc(sizeof(int));
496 ret = para_listen_simple(IPPROTO_TCP, port);
499 sct->listen_fds[0] = ret;
501 sct->num_listen_fds = OPT_GIVEN(LISTEN_ADDRESS);
502 sct->listen_fds = para_malloc(sct->num_listen_fds * sizeof(int));
503 for (n = 0; n < OPT_GIVEN(LISTEN_ADDRESS); n++) {
505 arg = lls_string_val(n, OPT_RESULT(LISTEN_ADDRESS));
506 ret = para_listen(IPPROTO_TCP, arg, port);
509 sct->listen_fds[n] = ret;
512 for (n = 0; n < sct->num_listen_fds; n++) {
513 ret = mark_fd_nonblocking(sct->listen_fds[n]);
516 /* child doesn't need the listener */
517 add_close_on_fork_list(sct->listen_fds[n]);
520 sct->task = task_register(&(struct task_info) {
521 .name = "server command",
522 .pre_select = command_pre_select,
523 .post_select = command_post_select,
528 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
532 static int init_afs(int argc, char **argv)
534 int ret, afs_server_socket[2];
537 ret = socketpair(PF_UNIX, SOCK_STREAM, 0, afs_server_socket);
540 get_random_bytes_or_die((unsigned char *)&afs_socket_cookie,
541 sizeof(afs_socket_cookie));
545 if (afs_pid == 0) { /* child (afs) */
551 for (i = argc - 1; i >= 0; i--)
552 memset(argv[i], 0, strlen(argv[i]));
553 i = argc - lls_num_inputs(cmdline_lpr) - 1;
554 sprintf(argv[i], "para_server (afs)");
555 close(afs_server_socket[0]);
556 afs_init(afs_server_socket[1]);
558 close(afs_server_socket[1]);
559 if (read(afs_server_socket[0], &c, 1) <= 0) {
560 PARA_EMERG_LOG("early afs exit\n");
563 ret = mark_fd_nonblocking(afs_server_socket[0]);
566 add_close_on_fork_list(afs_server_socket[0]);
567 PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
568 afs_server_socket[0], (unsigned) afs_socket_cookie);
569 return afs_server_socket[0];
572 static void handle_help_flags(void)
575 bool d = OPT_GIVEN(DETAILED_HELP);
578 help = lls_long_help(CMD_PTR);
579 else if (OPT_GIVEN(HELP))
580 help = lls_short_help(CMD_PTR);
583 printf("%s\n", help);
588 static void server_init(int argc, char **argv, struct server_command_task *sct)
590 int ret, afs_socket, daemon_pipe = -1;
594 /* parse command line options */
595 ret = lls(lls_parse(argc, argv, CMD_PTR, &cmdline_lpr, &errctx));
598 server_lpr = cmdline_lpr;
599 daemon_set_loglevel(ENUM_STRING_VAL(LOGLEVEL));
600 daemon_drop_privileges_or_die(OPT_STRING_VAL(USER),
601 OPT_STRING_VAL(GROUP));
602 version_handle_flag("server", OPT_GIVEN(VERSION));
604 parse_config_or_die(false);
606 if (OPT_GIVEN(DAEMON))
607 daemon_pipe = daemonize(true /* parent waits for SIGTERM */);
608 server_pid = getpid();
610 daemon_log_welcome("server");
611 init_ipc_or_die(); /* init mmd struct, mmd and log mutex */
612 daemon_set_start_time();
613 daemon_set_hooks(pre_log_hook, post_log_hook);
614 PARA_NOTICE_LOG("initializing audio format handlers\n");
618 * Although afs uses its own signal handling we must ignore SIGUSR1
619 * _before_ the afs child process gets born by init_afs() below. It's
620 * racy to do this in the child because the parent might send SIGUSR1
621 * before the child gets a chance to ignore this signal.
623 * We also have to block SIGCHLD before the afs process is created
624 * because otherwise para_server does not notice if afs dies before the
625 * SIGCHLD handler has been installed for the parent process by
626 * init_signal_task() below.
628 para_sigaction(SIGUSR1, SIG_IGN);
629 para_block_signal(SIGCHLD);
630 PARA_NOTICE_LOG("initializing the audio file selector\n");
631 afs_socket = init_afs(argc, argv);
633 para_unblock_signal(SIGCHLD);
634 PARA_NOTICE_LOG("initializing virtual streaming system\n");
635 vss_init(afs_socket, &sched);
636 init_server_command_task(sct, argc, argv);
637 if (daemon_pipe >= 0) {
638 if (write(daemon_pipe, "\0", 1) < 0) {
639 PARA_EMERG_LOG("daemon_pipe: %s", strerror(errno));
644 PARA_NOTICE_LOG("server init complete\n");
649 PARA_ERROR_LOG("%s\n", errctx);
650 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
654 static void status_refresh(void)
656 static int prev_uptime = -1, prev_events = -1;
657 int uptime = daemon_get_uptime(now);
659 if (prev_events != mmd->events)
661 if (mmd->new_vss_status_flags != mmd->vss_status_flags)
663 if (uptime / 60 != prev_uptime / 60)
669 prev_uptime = uptime;
670 prev_events = mmd->events;
671 mmd->vss_status_flags = mmd->new_vss_status_flags;
672 PARA_DEBUG_LOG("%u events, forcing status update\n", mmd->events);
676 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
677 struct timeval *timeout_tv)
682 mutex_unlock(mmd_mutex);
683 ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
684 mutex_lock(mmd_mutex);
689 * Deallocate all lopsub parse results.
691 * The server allocates a parse result for command line options and optionally
692 * a second parse result for the effective configuration, defined by merging
693 * the command line options with the options stored in the configuration file.
694 * This function frees both structures.
698 lls_free_parse_result(server_lpr, CMD_PTR);
699 if (server_lpr != cmdline_lpr)
700 lls_free_parse_result(cmdline_lpr, CMD_PTR);
704 * The main function of para_server.
706 * \param argc Usual argument count.
707 * \param argv Usual argument vector.
709 * \return EXIT_SUCCESS or EXIT_FAILURE.
711 int main(int argc, char *argv[])
714 struct server_command_task server_command_task_struct,
715 *sct = &server_command_task_struct;
717 sched.default_timeout.tv_sec = 1;
718 sched.select_function = server_select;
720 server_init(argc, argv, sct);
721 mutex_lock(mmd_mutex);
722 ret = schedule(&sched);
724 * We hold the mmd lock: it was re-acquired in server_select()
725 * after the select call.
727 mutex_unlock(mmd_mutex);
728 sched_shutdown(&sched);
730 signal_shutdown(signal_task);
731 if (!process_is_command_handler()) { /* parent (server) */
732 mutex_destroy(mmd_mutex);
733 daemon_set_hooks(NULL, NULL); /* only one process remaining */
734 mutex_destroy(log_mutex);
735 deplete_close_on_fork_list();
737 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
739 alarm(ALARM_TIMEOUT);
741 ret = handle_connect(sct->child_fd);
747 exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);