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 /** TCP port on which para_server listens for connections. */
134 /* File descriptor for the accepted socket. */
136 /** Copied from para_server's main function. */
138 /** Argument vector passed to para_server's main function. */
140 /** The command task structure for scheduling. */
145 * Return the list of tasks for the server process.
147 * This is called from \a com_tasks(). The helper is necessary since command
148 * handlers can not access the scheduler structure directly.
150 * \return A dynamically allocated string that must be freed by the caller.
152 char *server_get_tasks(void)
154 return get_task_list(&sched);
157 static void pre_log_hook(void)
159 mutex_lock(log_mutex);
162 static void post_log_hook(void)
164 mutex_unlock(log_mutex);
167 /* Setup shared memory area and init mutexes */
168 static void init_ipc_or_die(void)
171 int shmid, ret = shm_new(sizeof(struct misc_meta_data));
176 ret = shm_attach(shmid, ATTACH_RW, &shm);
188 goto destroy_mmd_mutex;
192 mmd->num_commands = 0;
194 mmd->num_connects = 0;
195 mmd->active_connections = 0;
196 mmd->vss_status_flags = VSS_NEXT;
197 mmd->new_vss_status_flags = VSS_NEXT;
200 mutex_destroy(mmd_mutex);
202 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
207 * (Re-)read the server configuration files.
209 * \param reload Whether config file overrides command line.
211 * This function also re-opens the logfile and the user list. On SIGHUP it is
212 * called from both server and afs context.
214 void parse_config_or_die(bool reload)
217 char *cf = NULL, *errctx = NULL, *user_list_file = NULL;
222 struct lls_parse_result *cf_lpr, *merged_lpr;
223 char *home = para_homedir();
225 if (OPT_GIVEN(CONFIG_FILE))
226 cf = para_strdup(OPT_STRING_VAL(CONFIG_FILE));
228 cf = make_message("%s/.paraslash/server.conf", home);
229 if (!mmd || getpid() != afs_pid) {
230 if (OPT_GIVEN(USER_LIST))
231 user_list_file = para_strdup(OPT_STRING_VAL(USER_LIST));
233 user_list_file = make_message("%s/.paraslash/server.users", home);
236 ret = mmap_full_file(cf, O_RDONLY, &map, &sz, NULL);
238 if (ret != -E_EMPTY && ret != -ERRNO_TO_PARA_ERROR(ENOENT))
240 if (ret == -ERRNO_TO_PARA_ERROR(ENOENT) && OPT_GIVEN(CONFIG_FILE))
242 server_lpr = cmdline_lpr;
245 ret = lls(lls_convert_config(map, sz, NULL, &cf_argv, &errctx));
246 para_munmap(map, sz);
250 ret = lls(lls_parse(cf_argc, cf_argv, CMD_PTR, &cf_lpr, &errctx));
251 lls_free_argv(cf_argv);
254 if (reload) /* config file overrides command line */
255 ret = lls(lls_merge(cf_lpr, cmdline_lpr, CMD_PTR, &merged_lpr,
257 else /* command line options override config file options */
258 ret = lls(lls_merge(cmdline_lpr, cf_lpr, CMD_PTR, &merged_lpr,
260 lls_free_parse_result(cf_lpr, CMD_PTR);
263 if (server_lpr != cmdline_lpr)
264 lls_free_parse_result(server_lpr, CMD_PTR);
265 server_lpr = merged_lpr;
267 daemon_set_loglevel(ENUM_STRING_VAL(LOGLEVEL));
268 if (OPT_GIVEN(LOGFILE)) {
269 daemon_set_logfile(OPT_STRING_VAL(LOGFILE));
270 daemon_open_log_or_die();
272 if (daemon_init_colors_or_die(OPT_UINT32_VAL(COLOR), COLOR_AUTO,
273 COLOR_NO, OPT_GIVEN(LOGFILE))) {
275 for (i = 0; i < OPT_GIVEN(LOG_COLOR); i++)
276 daemon_set_log_color_or_die(lls_string_val(i,
277 OPT_RESULT(LOG_COLOR)));
279 daemon_set_flag(DF_LOG_PID);
280 daemon_set_flag(DF_LOG_LL);
281 daemon_set_flag(DF_LOG_TIME);
282 if (OPT_GIVEN(LOG_TIMING))
283 daemon_set_flag(DF_LOG_TIMING);
284 daemon_set_priority(OPT_UINT32_VAL(PRIORITY));
286 user_list_init(user_list_file);
290 free(user_list_file);
293 PARA_ERROR_LOG("%s\n", errctx);
295 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
301 * called when server gets SIGHUP or when client invokes hup command.
303 static void handle_sighup(void)
306 PARA_NOTICE_LOG("SIGHUP\n");
307 parse_config_or_die(true);
309 kill(afs_pid, SIGHUP);
312 static int signal_post_select(struct sched *s, __a_unused void *context)
316 ret = task_get_notification(signal_task->task);
319 signum = para_next_signal(&s->rfds);
329 ret = para_reap_child(&pid);
334 PARA_EMERG_LOG("fatal: afs died\n");
339 /* die on sigint/sigterm. Kill all children too. */
342 PARA_EMERG_LOG("terminating on signal %d\n", signum);
345 * We must wait for all of our children to die. For the afs
346 * process or a command handler might want to use the
347 * shared memory area and the mmd mutex. If we destroy this
348 * mutex too early and afs tries to lock the shared memory
349 * area, the call to mutex_lock() will fail and terminate the
350 * afs process. This leads to dirty osl tables.
352 PARA_INFO_LOG("waiting for child processes to die\n");
353 mutex_unlock(mmd_mutex);
354 while (wait(NULL) != -1 || errno != ECHILD)
355 ; /* still at least one child alive */
356 mutex_lock(mmd_mutex);
358 free(mmd->afd.afhi.chunk_table);
359 task_notify_all(s, E_DEADLY_SIGNAL);
360 return -E_DEADLY_SIGNAL;
365 static void init_signal_task(void)
367 signal_task = signal_init_or_die();
368 para_install_sighandler(SIGINT);
369 para_install_sighandler(SIGTERM);
370 para_install_sighandler(SIGHUP);
371 para_install_sighandler(SIGCHLD);
372 para_sigaction(SIGPIPE, SIG_IGN);
373 add_close_on_fork_list(signal_task->fd);
374 signal_task->task = task_register(&(struct task_info) {
376 .pre_select = signal_pre_select,
377 .post_select = signal_post_select,
378 .context = signal_task,
383 static void command_pre_select(struct sched *s, void *context)
385 struct server_command_task *sct = context;
386 para_fd_set(sct->listen_fd, &s->rfds, &s->max_fileno);
389 static int command_post_select(struct sched *s, void *context)
391 struct server_command_task *sct = context;
395 uint32_t *chunk_table;
397 ret = task_get_notification(sct->task);
400 ret = para_accept(sct->listen_fd, &s->rfds, NULL, 0, &new_fd);
404 mmd->active_connections++;
406 * The chunk table is a pointer located in the mmd struct that points
407 * to dynamically allocated memory, i.e. it must be freed by the parent
408 * and the child. However, as the mmd struct is in a shared memory
409 * area, there's no guarantee that after the fork this pointer is still
410 * valid in child context. As it is not used in the child anyway, we
411 * save it to a local variable before the fork and free the memory via
412 * that copy in the child directly after the fork.
414 chunk_table = mmd->afd.afhi.chunk_table;
417 ret = -ERRNO_TO_PARA_ERROR(errno);
421 /* avoid problems with non-fork-safe PRNGs */
422 unsigned char buf[16];
423 get_random_bytes_or_die(buf, sizeof(buf));
425 /* parent keeps accepting connections */
428 peer_name = remote_name(new_fd);
429 PARA_INFO_LOG("accepted connection from %s\n", peer_name);
430 /* mmd might already have changed at this point */
432 sct->child_fd = new_fd;
434 * put info on who we are serving into argv[0] to make
435 * client ip visible in top/ps
437 for (i = sct->argc - 1; i >= 0; i--)
438 memset(sct->argv[i], 0, strlen(sct->argv[i]));
439 i = sct->argc - 1 - lls_num_inputs(cmdline_lpr);
440 sprintf(sct->argv[i], "para_server (serving %s)", peer_name);
441 /* ask other tasks to terminate */
442 task_notify_all(s, E_CHILD_CONTEXT);
444 * After we return, the scheduler calls server_select() with a minimal
445 * timeout value, because the remaining tasks have a notification
446 * pending. Next it calls the ->post_select method of these tasks,
447 * which will return negative in view of the notification. This causes
448 * schedule() to return as there are no more runnable tasks.
450 * Note that semaphores are not inherited across a fork(), so we don't
451 * hold the lock at this point. Since server_select() drops the lock
452 * prior to calling para_select(), we need to acquire it here.
454 mutex_lock(mmd_mutex);
455 return -E_CHILD_CONTEXT;
458 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
462 static void init_server_command_task(struct server_command_task *sct,
463 int argc, char **argv)
467 PARA_NOTICE_LOG("initializing tcp command socket\n");
471 ret = para_listen_simple(IPPROTO_TCP, OPT_UINT32_VAL(PORT));
474 sct->listen_fd = ret;
475 ret = mark_fd_nonblocking(sct->listen_fd);
478 add_close_on_fork_list(sct->listen_fd); /* child doesn't need the listener */
479 sct->task = task_register(&(struct task_info) {
480 .name = "server command",
481 .pre_select = command_pre_select,
482 .post_select = command_post_select,
487 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
491 static int init_afs(int argc, char **argv)
493 int ret, afs_server_socket[2];
496 ret = socketpair(PF_UNIX, SOCK_STREAM, 0, afs_server_socket);
499 get_random_bytes_or_die((unsigned char *)&afs_socket_cookie,
500 sizeof(afs_socket_cookie));
504 if (afs_pid == 0) { /* child (afs) */
510 for (i = argc - 1; i >= 0; i--)
511 memset(argv[i], 0, strlen(argv[i]));
512 i = argc - lls_num_inputs(cmdline_lpr) - 1;
513 sprintf(argv[i], "para_server (afs)");
514 close(afs_server_socket[0]);
515 afs_init(afs_server_socket[1]);
517 close(afs_server_socket[1]);
518 if (read(afs_server_socket[0], &c, 1) <= 0) {
519 PARA_EMERG_LOG("early afs exit\n");
522 ret = mark_fd_nonblocking(afs_server_socket[0]);
525 add_close_on_fork_list(afs_server_socket[0]);
526 PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
527 afs_server_socket[0], (unsigned) afs_socket_cookie);
528 return afs_server_socket[0];
531 static void handle_help_flags(void)
534 bool d = OPT_GIVEN(DETAILED_HELP);
537 help = lls_long_help(CMD_PTR);
538 else if (OPT_GIVEN(HELP))
539 help = lls_short_help(CMD_PTR);
542 printf("%s\n", help);
547 static void server_init(int argc, char **argv, struct server_command_task *sct)
549 int ret, afs_socket, daemon_pipe = -1;
553 /* parse command line options */
554 ret = lls(lls_parse(argc, argv, CMD_PTR, &cmdline_lpr, &errctx));
557 server_lpr = cmdline_lpr;
558 daemon_set_loglevel(ENUM_STRING_VAL(LOGLEVEL));
559 daemon_drop_privileges_or_die(OPT_STRING_VAL(USER),
560 OPT_STRING_VAL(GROUP));
561 version_handle_flag("server", OPT_GIVEN(VERSION));
563 parse_config_or_die(false);
565 if (OPT_GIVEN(DAEMON))
566 daemon_pipe = daemonize(true /* parent waits for SIGTERM */);
567 server_pid = getpid();
569 daemon_log_welcome("server");
570 init_ipc_or_die(); /* init mmd struct, mmd and log mutex */
571 daemon_set_start_time();
572 daemon_set_hooks(pre_log_hook, post_log_hook);
573 PARA_NOTICE_LOG("initializing audio format handlers\n");
577 * Although afs uses its own signal handling we must ignore SIGUSR1
578 * _before_ the afs child process gets born by init_afs() below. It's
579 * racy to do this in the child because the parent might send SIGUSR1
580 * before the child gets a chance to ignore this signal.
582 * We also have to block SIGCHLD before the afs process is created
583 * because otherwise para_server does not notice if afs dies before the
584 * SIGCHLD handler has been installed for the parent process by
585 * init_signal_task() below.
587 para_sigaction(SIGUSR1, SIG_IGN);
588 para_block_signal(SIGCHLD);
589 PARA_NOTICE_LOG("initializing the audio file selector\n");
590 afs_socket = init_afs(argc, argv);
592 para_unblock_signal(SIGCHLD);
593 PARA_NOTICE_LOG("initializing virtual streaming system\n");
594 vss_init(afs_socket, &sched);
595 init_server_command_task(sct, argc, argv);
596 if (daemon_pipe >= 0) {
597 if (write(daemon_pipe, "\0", 1) < 0) {
598 PARA_EMERG_LOG("daemon_pipe: %s", strerror(errno));
603 PARA_NOTICE_LOG("server init complete\n");
608 PARA_ERROR_LOG("%s\n", errctx);
609 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
613 static void status_refresh(void)
615 static int prev_uptime = -1, prev_events = -1;
616 int uptime = daemon_get_uptime(now);
618 if (prev_events != mmd->events)
620 if (mmd->new_vss_status_flags != mmd->vss_status_flags)
622 if (uptime / 60 != prev_uptime / 60)
628 prev_uptime = uptime;
629 prev_events = mmd->events;
630 mmd->vss_status_flags = mmd->new_vss_status_flags;
631 PARA_DEBUG_LOG("%u events, forcing status update\n", mmd->events);
635 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
636 struct timeval *timeout_tv)
641 mutex_unlock(mmd_mutex);
642 ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
643 mutex_lock(mmd_mutex);
648 * Deallocate all lopsub parse results.
650 * The server allocates a parse result for command line options and optionally
651 * a second parse result for the effective configuration, defined by merging
652 * the command line options with the options stored in the configuration file.
653 * This function frees both structures.
657 lls_free_parse_result(server_lpr, CMD_PTR);
658 if (server_lpr != cmdline_lpr)
659 lls_free_parse_result(cmdline_lpr, CMD_PTR);
663 * The main function of para_server.
665 * \param argc Usual argument count.
666 * \param argv Usual argument vector.
668 * \return EXIT_SUCCESS or EXIT_FAILURE.
670 int main(int argc, char *argv[])
673 struct server_command_task server_command_task_struct,
674 *sct = &server_command_task_struct;
676 sched.default_timeout.tv_sec = 1;
677 sched.select_function = server_select;
679 server_init(argc, argv, sct);
680 mutex_lock(mmd_mutex);
681 ret = schedule(&sched);
683 * We hold the mmd lock: it was re-acquired in server_select()
684 * after the select call.
686 mutex_unlock(mmd_mutex);
687 sched_shutdown(&sched);
689 signal_shutdown(signal_task);
690 if (!process_is_command_handler()) { /* parent (server) */
691 mutex_destroy(mmd_mutex);
692 daemon_set_hooks(NULL, NULL); /* only one process remaining */
693 mutex_destroy(log_mutex);
694 deplete_close_on_fork_list();
696 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
698 alarm(ALARM_TIMEOUT);
700 ret = handle_connect(sct->child_fd);
706 exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);