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 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");
305 /* die on sigint/sigterm. Kill all children too. */
308 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
);
324 free(mmd
->afd
.afhi
.chunk_table
);
325 task_notify_all(s
, E_DEADLY_SIGNAL
);
326 return -E_DEADLY_SIGNAL
;
331 static void init_signal_task(void)
333 signal_task
= signal_init_or_die();
334 para_install_sighandler(SIGINT
);
335 para_install_sighandler(SIGTERM
);
336 para_install_sighandler(SIGHUP
);
337 para_install_sighandler(SIGCHLD
);
338 para_sigaction(SIGPIPE
, SIG_IGN
);
339 add_close_on_fork_list(signal_task
->fd
);
340 signal_task
->task
= task_register(&(struct task_info
) {
342 .pre_select
= signal_pre_select
,
343 .post_select
= signal_post_select
,
344 .context
= signal_task
,
349 static void command_pre_select(struct sched
*s
, void *context
)
352 struct server_command_task
*sct
= context
;
354 for (n
= 0; n
< sct
->num_listen_fds
; n
++)
355 para_fd_set(sct
->listen_fds
[n
], &s
->rfds
, &s
->max_fileno
);
358 static int command_task_accept(unsigned listen_idx
, struct sched
*s
,
359 struct server_command_task
*sct
)
364 uint32_t *chunk_table
;
366 ret
= para_accept(sct
->listen_fds
[listen_idx
], &s
->rfds
, NULL
, 0, &new_fd
);
370 mmd
->active_connections
++;
372 * The chunk table is a pointer located in the mmd struct that points
373 * to dynamically allocated memory, i.e. it must be freed by the parent
374 * and the child. However, as the mmd struct is in a shared memory
375 * area, there's no guarantee that after the fork this pointer is still
376 * valid in child context. As it is not used in the child anyway, we
377 * save it to a local variable before the fork and free the memory via
378 * that copy in the child directly after the fork.
380 chunk_table
= mmd
->afd
.afhi
.chunk_table
;
383 ret
= -ERRNO_TO_PARA_ERROR(errno
);
387 /* avoid problems with non-fork-safe PRNGs */
388 unsigned char buf
[16];
389 get_random_bytes_or_die(buf
, sizeof(buf
));
391 /* parent keeps accepting connections */
394 peer_name
= remote_name(new_fd
);
395 PARA_INFO_LOG("accepted connection from %s\n", peer_name
);
396 /* mmd might already have changed at this point */
398 sct
->child_fd
= new_fd
;
400 * put info on who we are serving into argv[0] to make
401 * client ip visible in top/ps
403 for (i
= sct
->argc
- 1; i
>= 0; i
--)
404 memset(sct
->argv
[i
], 0, strlen(sct
->argv
[i
]));
405 i
= sct
->argc
- 1 - lls_num_inputs(cmdline_lpr
);
406 sprintf(sct
->argv
[i
], "para_server (serving %s)", peer_name
);
407 /* ask other tasks to terminate */
408 task_notify_all(s
, E_CHILD_CONTEXT
);
410 * After we return, the scheduler calls server_select() with a minimal
411 * timeout value, because the remaining tasks have a notification
412 * pending. Next it calls the ->post_select method of these tasks,
413 * which will return negative in view of the notification. This causes
414 * schedule() to return as there are no more runnable tasks.
416 * Note that semaphores are not inherited across a fork(), so we don't
417 * hold the lock at this point. Since server_select() drops the lock
418 * prior to calling para_select(), we need to acquire it here.
420 mutex_lock(mmd_mutex
);
421 return -E_CHILD_CONTEXT
;
424 PARA_CRIT_LOG("%s\n", para_strerror(-ret
));
428 static int command_post_select(struct sched
*s
, void *context
)
430 struct server_command_task
*sct
= context
;
434 ret
= task_get_notification(sct
->task
);
437 for (n
= 0; n
< sct
->num_listen_fds
; n
++) {
438 ret
= command_task_accept(n
, s
, sct
);
440 free(sct
->listen_fds
);
447 static void init_server_command_task(struct server_command_task
*sct
,
448 int argc
, char **argv
)
452 uint32_t port
= OPT_UINT32_VAL(PORT
);
454 PARA_NOTICE_LOG("initializing tcp command socket\n");
458 if (!OPT_GIVEN(LISTEN_ADDRESS
)) {
459 sct
->num_listen_fds
= 1;
460 sct
->listen_fds
= para_malloc(sizeof(int));
461 ret
= para_listen_simple(IPPROTO_TCP
, port
);
464 sct
->listen_fds
[0] = ret
;
466 sct
->num_listen_fds
= OPT_GIVEN(LISTEN_ADDRESS
);
467 sct
->listen_fds
= para_malloc(sct
->num_listen_fds
* sizeof(int));
468 for (n
= 0; n
< OPT_GIVEN(LISTEN_ADDRESS
); n
++) {
470 arg
= lls_string_val(n
, OPT_RESULT(LISTEN_ADDRESS
));
471 ret
= para_listen(IPPROTO_TCP
, arg
, port
);
474 sct
->listen_fds
[n
] = ret
;
477 for (n
= 0; n
< sct
->num_listen_fds
; n
++) {
478 ret
= mark_fd_nonblocking(sct
->listen_fds
[n
]);
481 /* child doesn't need the listener */
482 add_close_on_fork_list(sct
->listen_fds
[n
]);
485 sct
->task
= task_register(&(struct task_info
) {
486 .name
= "server command",
487 .pre_select
= command_pre_select
,
488 .post_select
= command_post_select
,
492 * Detect whether the abstract Unix domain socket space is supported,
493 * but do not create the socket. We check this once in server context
494 * so that the command handlers inherit this bit of information and
495 * don't need to check again.
497 create_local_socket(NULL
);
500 PARA_EMERG_LOG("%s\n", para_strerror(-ret
));
504 static int init_afs(int argc
, char **argv
)
506 int ret
, afs_server_socket
[2];
509 ret
= socketpair(PF_UNIX
, SOCK_STREAM
, 0, afs_server_socket
);
512 get_random_bytes_or_die((unsigned char *)&afs_socket_cookie
,
513 sizeof(afs_socket_cookie
));
517 if (afs_pid
== 0) { /* child (afs) */
523 for (i
= argc
- 1; i
>= 0; i
--)
524 memset(argv
[i
], 0, strlen(argv
[i
]));
525 i
= argc
- lls_num_inputs(cmdline_lpr
) - 1;
526 sprintf(argv
[i
], "para_server (afs)");
527 close(afs_server_socket
[0]);
528 afs_init(afs_server_socket
[1]);
530 close(afs_server_socket
[1]);
531 if (read(afs_server_socket
[0], &c
, 1) <= 0) {
532 PARA_EMERG_LOG("early afs exit\n");
535 ret
= mark_fd_nonblocking(afs_server_socket
[0]);
538 add_close_on_fork_list(afs_server_socket
[0]);
539 PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
540 afs_server_socket
[0], (unsigned) afs_socket_cookie
);
541 return afs_server_socket
[0];
544 static void handle_help_flags(void)
547 bool d
= OPT_GIVEN(DETAILED_HELP
);
550 help
= lls_long_help(CMD_PTR
);
551 else if (OPT_GIVEN(HELP
))
552 help
= lls_short_help(CMD_PTR
);
555 printf("%s\n", help
);
560 static void server_init(int argc
, char **argv
, struct server_command_task
*sct
)
562 int ret
, afs_socket
, daemon_pipe
= -1;
566 /* parse command line options */
567 ret
= lls(lls_parse(argc
, argv
, CMD_PTR
, &cmdline_lpr
, &errctx
));
570 server_lpr
= cmdline_lpr
;
571 daemon_set_loglevel(ENUM_STRING_VAL(LOGLEVEL
));
572 daemon_drop_privileges_or_die(OPT_STRING_VAL(USER
),
573 OPT_STRING_VAL(GROUP
));
574 version_handle_flag("server", OPT_GIVEN(VERSION
));
576 parse_config_or_die(false);
578 if (OPT_GIVEN(DAEMON
))
579 daemon_pipe
= daemonize(true /* parent waits for SIGTERM */);
580 server_pid
= getpid();
582 daemon_log_welcome("server");
583 init_ipc_or_die(); /* init mmd struct, mmd and log mutex */
584 daemon_set_start_time();
585 daemon_set_hooks(pre_log_hook
, post_log_hook
);
586 PARA_NOTICE_LOG("initializing audio format handlers\n");
590 * Although afs uses its own signal handling we must ignore SIGUSR1
591 * _before_ the afs child process gets born by init_afs() below. It's
592 * racy to do this in the child because the parent might send SIGUSR1
593 * before the child gets a chance to ignore this signal.
595 * We also have to block SIGCHLD before the afs process is created
596 * because otherwise para_server does not notice if afs dies before the
597 * SIGCHLD handler has been installed for the parent process by
598 * init_signal_task() below.
600 para_sigaction(SIGUSR1
, SIG_IGN
);
601 para_block_signal(SIGCHLD
);
602 PARA_NOTICE_LOG("initializing the audio file selector\n");
603 afs_socket
= init_afs(argc
, argv
);
605 para_unblock_signal(SIGCHLD
);
606 PARA_NOTICE_LOG("initializing virtual streaming system\n");
607 vss_init(afs_socket
, &sched
);
608 init_server_command_task(sct
, argc
, argv
);
609 if (daemon_pipe
>= 0) {
610 if (write(daemon_pipe
, "\0", 1) < 0) {
611 PARA_EMERG_LOG("daemon_pipe: %s", strerror(errno
));
616 PARA_NOTICE_LOG("server init complete\n");
621 PARA_ERROR_LOG("%s\n", errctx
);
622 PARA_EMERG_LOG("%s\n", para_strerror(-ret
));
626 static void status_refresh(void)
628 static int prev_uptime
= -1, prev_events
= -1;
629 int uptime
= daemon_get_uptime(now
);
631 if (prev_events
!= mmd
->events
)
633 if (mmd
->new_vss_status_flags
!= mmd
->vss_status_flags
)
635 if (uptime
/ 60 != prev_uptime
/ 60)
641 prev_uptime
= uptime
;
642 prev_events
= mmd
->events
;
643 mmd
->vss_status_flags
= mmd
->new_vss_status_flags
;
644 PARA_DEBUG_LOG("%u events, forcing status update\n", mmd
->events
);
648 static int server_select(int max_fileno
, fd_set
*readfds
, fd_set
*writefds
,
649 struct timeval
*timeout_tv
)
654 mutex_unlock(mmd_mutex
);
655 ret
= para_select(max_fileno
+ 1, readfds
, writefds
, timeout_tv
);
656 mutex_lock(mmd_mutex
);
661 * Deallocate all lopsub parse results.
663 * The server allocates a parse result for command line options and optionally
664 * a second parse result for the effective configuration, defined by merging
665 * the command line options with the options stored in the configuration file.
666 * This function frees both structures.
670 lls_free_parse_result(server_lpr
, CMD_PTR
);
671 if (server_lpr
!= cmdline_lpr
)
672 lls_free_parse_result(cmdline_lpr
, CMD_PTR
);
676 * The main function of para_server.
678 * \param argc Usual argument count.
679 * \param argv Usual argument vector.
681 * \return EXIT_SUCCESS or EXIT_FAILURE.
683 int main(int argc
, char *argv
[])
686 struct server_command_task server_command_task_struct
,
687 *sct
= &server_command_task_struct
;
689 sched
.default_timeout
.tv_sec
= 1;
690 sched
.select_function
= server_select
;
692 server_init(argc
, argv
, sct
);
693 mutex_lock(mmd_mutex
);
694 ret
= schedule(&sched
);
696 * We hold the mmd lock: it was re-acquired in server_select()
697 * after the select call.
699 mutex_unlock(mmd_mutex
);
700 sched_shutdown(&sched
);
702 signal_shutdown(signal_task
);
703 if (!process_is_command_handler()) { /* parent (server) */
704 mutex_destroy(mmd_mutex
);
705 daemon_set_hooks(NULL
, NULL
); /* only one process remaining */
706 mutex_destroy(log_mutex
);
707 deplete_close_on_fork_list();
709 PARA_EMERG_LOG("%s\n", para_strerror(-ret
));
711 alarm(ALARM_TIMEOUT
);
713 ret
= handle_connect(sct
->child_fd
);
719 exit(ret
< 0? EXIT_FAILURE
: EXIT_SUCCESS
);