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 static struct sched sched
;
104 static struct signal_task
*signal_task
;
106 /** The process id of the audio file selector process. */
109 /** The task responsible for server command handling. */
110 struct server_command_task
{
111 /** TCP port on which para_server listens for connections. */
113 /** Copied from para_server's main function. */
115 /** Argument vector passed to para_server's main function. */
117 /** The command task structure for scheduling. */
122 * Return the list of tasks for the server process.
124 * This is called from \a com_tasks(). The helper is necessary since command
125 * handlers can not access the scheduler structure directly.
127 * \return A dynamically allocated string that must be freed by the caller.
129 char *server_get_tasks(void)
131 return get_task_list(&sched
);
135 * setup shared memory area and get mutex for locking
137 static void init_ipc_or_die(void)
140 int shmid
, ret
= shm_new(sizeof(struct misc_meta_data
));
145 ret
= shm_attach(shmid
, ATTACH_RW
, &shm
);
157 mmd
->num_commands
= 0;
159 mmd
->num_connects
= 0;
160 mmd
->active_connections
= 0;
161 mmd
->vss_status_flags
= VSS_NEXT
;
162 mmd
->new_vss_status_flags
= VSS_NEXT
;
165 PARA_EMERG_LOG("%s\n", para_strerror(-ret
));
170 * (Re-)read the server configuration files.
172 * \param reload Whether config file overrides command line.
174 * This function also re-opens the logfile and the user list. On SIGHUP it is
175 * called from both server and afs context.
177 void parse_config_or_die(bool reload
)
180 char *cf
= NULL
, *errctx
= NULL
, *user_list_file
= NULL
;
185 struct lls_parse_result
*cf_lpr
, *merged_lpr
;
186 char *home
= para_homedir();
188 if (OPT_GIVEN(CONFIG_FILE
))
189 cf
= para_strdup(OPT_STRING_VAL(CONFIG_FILE
));
191 cf
= make_message("%s/.paraslash/server.conf", home
);
192 if (!mmd
|| getpid() != afs_pid
) {
193 if (OPT_GIVEN(USER_LIST
))
194 user_list_file
= para_strdup(OPT_STRING_VAL(USER_LIST
));
196 user_list_file
= make_message("%s/.paraslash/server.users", home
);
199 ret
= mmap_full_file(cf
, O_RDONLY
, &map
, &sz
, NULL
);
201 if (ret
!= -E_EMPTY
&& ret
!= -ERRNO_TO_PARA_ERROR(ENOENT
))
203 if (ret
== -ERRNO_TO_PARA_ERROR(ENOENT
) && OPT_GIVEN(CONFIG_FILE
))
205 server_lpr
= cmdline_lpr
;
208 ret
= lls(lls_convert_config(map
, sz
, NULL
, &cf_argv
, &errctx
));
209 para_munmap(map
, sz
);
213 ret
= lls(lls_parse(cf_argc
, cf_argv
, CMD_PTR
, &cf_lpr
, &errctx
));
214 lls_free_argv(cf_argv
);
217 if (reload
) /* config file overrides command line */
218 ret
= lls(lls_merge(cf_lpr
, cmdline_lpr
, CMD_PTR
, &merged_lpr
,
220 else /* command line options override config file options */
221 ret
= lls(lls_merge(cmdline_lpr
, cf_lpr
, CMD_PTR
, &merged_lpr
,
223 lls_free_parse_result(cf_lpr
, CMD_PTR
);
226 if (server_lpr
!= cmdline_lpr
)
227 lls_free_parse_result(server_lpr
, CMD_PTR
);
228 server_lpr
= merged_lpr
;
230 daemon_set_loglevel(ENUM_STRING_VAL(LOGLEVEL
));
231 if (OPT_GIVEN(LOGFILE
)) {
232 daemon_set_logfile(OPT_STRING_VAL(LOGFILE
));
233 daemon_open_log_or_die();
235 if (daemon_init_colors_or_die(OPT_UINT32_VAL(COLOR
), COLOR_AUTO
,
236 COLOR_NO
, OPT_GIVEN(LOGFILE
))) {
238 for (i
= 0; i
< OPT_GIVEN(LOG_COLOR
); i
++)
239 daemon_set_log_color_or_die(lls_string_val(i
,
240 OPT_RESULT(LOG_COLOR
)));
242 daemon_set_flag(DF_LOG_PID
);
243 daemon_set_flag(DF_LOG_LL
);
244 daemon_set_flag(DF_LOG_TIME
);
245 if (OPT_GIVEN(LOG_TIMING
))
246 daemon_set_flag(DF_LOG_TIMING
);
247 daemon_set_priority(OPT_UINT32_VAL(PRIORITY
));
249 init_user_list(user_list_file
);
253 free(user_list_file
);
256 PARA_ERROR_LOG("%s\n", errctx
);
258 PARA_EMERG_LOG("%s\n", para_strerror(-ret
));
264 * called when server gets SIGHUP or when client invokes hup command.
266 static void handle_sighup(void)
269 PARA_NOTICE_LOG("SIGHUP\n");
270 parse_config_or_die(true);
272 kill(afs_pid
, SIGHUP
);
275 static int signal_post_select(struct sched
*s
, __a_unused
void *context
)
277 int signum
= para_next_signal(&s
->rfds
);
288 int ret
= para_reap_child(&pid
);
293 PARA_EMERG_LOG("fatal: afs died\n");
298 /* die on sigint/sigterm. Kill all children too. */
301 PARA_EMERG_LOG("terminating on signal %d\n", signum
);
304 * We must wait for afs because afs catches SIGINT/SIGTERM.
305 * Before reacting to the signal, afs might want to use the
306 * shared memory area and the mmd mutex. If we destroy this
307 * mutex too early and afs tries to lock the shared memory
308 * area, the call to mutex_lock() will fail and terminate the
309 * afs process. This leads to dirty osl tables.
311 * There's no such problem with the other children of the
312 * server process (the command handlers) as these reset their
313 * SIGINT/SIGTERM handlers to the default action, i.e. these
314 * processes get killed immediately by the above kill().
316 PARA_INFO_LOG("waiting for afs (pid %d) to die\n",
318 waitpid(afs_pid
, NULL
, 0);
320 free(mmd
->afd
.afhi
.chunk_table
);
322 mutex_destroy(mmd_mutex
);
329 static void init_signal_task(void)
331 signal_task
= signal_init_or_die();
332 para_install_sighandler(SIGINT
);
333 para_install_sighandler(SIGTERM
);
334 para_install_sighandler(SIGHUP
);
335 para_install_sighandler(SIGCHLD
);
336 para_sigaction(SIGPIPE
, SIG_IGN
);
337 add_close_on_fork_list(signal_task
->fd
);
338 signal_task
->task
= task_register(&(struct task_info
) {
340 .pre_select
= signal_pre_select
,
341 .post_select
= signal_post_select
,
342 .context
= signal_task
,
347 static void command_pre_select(struct sched
*s
, void *context
)
349 struct server_command_task
*sct
= context
;
350 para_fd_set(sct
->listen_fd
, &s
->rfds
, &s
->max_fileno
);
353 static int command_post_select(struct sched
*s
, void *context
)
355 struct server_command_task
*sct
= context
;
360 uint32_t *chunk_table
;
362 ret
= para_accept(sct
->listen_fd
, &s
->rfds
, NULL
, 0, &new_fd
);
366 mmd
->active_connections
++;
368 * The chunk table is a pointer located in the mmd struct that points
369 * to dynamically allocated memory, i.e. it must be freed by the parent
370 * and the child. However, as the mmd struct is in a shared memory
371 * area, there's no guarantee that after the fork this pointer is still
372 * valid in child context. As it is not used in the child anyway, we
373 * save it to a local variable before the fork and free the memory via
374 * that copy in the child directly after the fork.
376 chunk_table
= mmd
->afd
.afhi
.chunk_table
;
379 ret
= -ERRNO_TO_PARA_ERROR(errno
);
383 /* avoid problems with non-fork-safe PRNGs */
384 unsigned char buf
[16];
385 get_random_bytes_or_die(buf
, sizeof(buf
));
387 /* parent keeps accepting connections */
390 peer_name
= remote_name(new_fd
);
391 PARA_INFO_LOG("accepted connection from %s\n", peer_name
);
392 /* mmd might already have changed at this point */
394 alarm(ALARM_TIMEOUT
);
396 signal_shutdown(signal_task
);
398 * put info on who we are serving into argv[0] to make
399 * client ip visible in top/ps
401 for (i
= sct
->argc
- 1; i
>= 0; i
--)
402 memset(sct
->argv
[i
], 0, strlen(sct
->argv
[i
]));
403 i
= sct
->argc
- 1 - lls_num_inputs(cmdline_lpr
);
404 sprintf(sct
->argv
[i
], "para_server (serving %s)", peer_name
);
405 handle_connect(new_fd
);
409 PARA_CRIT_LOG("%s\n", para_strerror(-ret
));
413 static void init_server_command_task(int argc
, char **argv
)
416 static struct server_command_task server_command_task_struct
,
417 *sct
= &server_command_task_struct
;
419 PARA_NOTICE_LOG("initializing tcp command socket\n");
422 ret
= para_listen_simple(IPPROTO_TCP
, OPT_UINT32_VAL(PORT
));
425 sct
->listen_fd
= ret
;
426 ret
= mark_fd_nonblocking(sct
->listen_fd
);
429 add_close_on_fork_list(sct
->listen_fd
); /* child doesn't need the listener */
430 sct
->task
= task_register(&(struct task_info
) {
431 .name
= "server command",
432 .pre_select
= command_pre_select
,
433 .post_select
= command_post_select
,
438 PARA_EMERG_LOG("%s\n", para_strerror(-ret
));
442 static int init_afs(int argc
, char **argv
)
444 int ret
, afs_server_socket
[2];
447 ret
= socketpair(PF_UNIX
, SOCK_STREAM
, 0, afs_server_socket
);
450 get_random_bytes_or_die((unsigned char *)&afs_socket_cookie
,
451 sizeof(afs_socket_cookie
));
455 if (afs_pid
== 0) { /* child (afs) */
460 for (i
= argc
- 1; i
>= 0; i
--)
461 memset(argv
[i
], 0, strlen(argv
[i
]));
462 i
= argc
- lls_num_inputs(cmdline_lpr
) - 1;
463 sprintf(argv
[i
], "para_server (afs)");
464 close(afs_server_socket
[0]);
465 afs_init(afs_server_socket
[1]);
467 close(afs_server_socket
[1]);
468 if (read(afs_server_socket
[0], &c
, 1) <= 0) {
469 PARA_EMERG_LOG("early afs exit\n");
472 ret
= mark_fd_nonblocking(afs_server_socket
[0]);
475 add_close_on_fork_list(afs_server_socket
[0]);
476 PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
477 afs_server_socket
[0], (unsigned) afs_socket_cookie
);
478 return afs_server_socket
[0];
481 static void handle_help_flags(void)
484 bool d
= OPT_GIVEN(DETAILED_HELP
);
487 help
= lls_long_help(CMD_PTR
);
488 else if (OPT_GIVEN(HELP
))
489 help
= lls_short_help(CMD_PTR
);
492 printf("%s\n", help
);
497 static void server_init(int argc
, char **argv
)
499 int ret
, afs_socket
, daemon_pipe
= -1;
503 /* parse command line options */
504 ret
= lls(lls_parse(argc
, argv
, CMD_PTR
, &cmdline_lpr
, &errctx
));
507 server_lpr
= cmdline_lpr
;
508 daemon_set_loglevel(ENUM_STRING_VAL(LOGLEVEL
));
509 daemon_drop_privileges_or_die(OPT_STRING_VAL(USER
),
510 OPT_STRING_VAL(GROUP
));
511 version_handle_flag("server", OPT_GIVEN(VERSION
));
513 parse_config_or_die(false);
515 if (OPT_GIVEN(DAEMON
))
516 daemon_pipe
= daemonize(true /* parent waits for SIGTERM */);
518 daemon_log_welcome("server");
519 init_ipc_or_die(); /* init mmd struct and mmd->lock */
520 daemon_set_start_time();
521 PARA_NOTICE_LOG("initializing audio format handlers\n");
525 * Although afs uses its own signal handling we must ignore SIGUSR1
526 * _before_ the afs child process gets born by init_afs() below. It's
527 * racy to do this in the child because the parent might send SIGUSR1
528 * before the child gets a chance to ignore this signal.
530 * We also have to block SIGCHLD before the afs process is created
531 * because otherwise para_server does not notice if afs dies before the
532 * SIGCHLD handler has been installed for the parent process by
533 * init_signal_task() below.
535 para_sigaction(SIGUSR1
, SIG_IGN
);
536 para_block_signal(SIGCHLD
);
537 PARA_NOTICE_LOG("initializing the audio file selector\n");
538 afs_socket
= init_afs(argc
, argv
);
540 para_unblock_signal(SIGCHLD
);
541 PARA_NOTICE_LOG("initializing virtual streaming system\n");
542 vss_init(afs_socket
, &sched
);
543 init_server_command_task(argc
, argv
);
544 if (daemon_pipe
>= 0) {
545 if (write(daemon_pipe
, "\0", 1) < 0) {
546 PARA_EMERG_LOG("daemon_pipe: %s", strerror(errno
));
551 PARA_NOTICE_LOG("server init complete\n");
556 PARA_ERROR_LOG("%s\n", errctx
);
557 PARA_EMERG_LOG("%s\n", para_strerror(-ret
));
561 static void status_refresh(void)
563 static int prev_uptime
= -1, prev_events
= -1;
564 int uptime
= daemon_get_uptime(now
);
566 if (prev_events
!= mmd
->events
)
568 if (mmd
->new_vss_status_flags
!= mmd
->vss_status_flags
)
570 if (uptime
/ 60 != prev_uptime
/ 60)
576 prev_uptime
= uptime
;
577 prev_events
= mmd
->events
;
578 mmd
->vss_status_flags
= mmd
->new_vss_status_flags
;
579 PARA_DEBUG_LOG("%u events, forcing status update\n", mmd
->events
);
583 static int server_select(int max_fileno
, fd_set
*readfds
, fd_set
*writefds
,
584 struct timeval
*timeout_tv
)
589 mutex_unlock(mmd_mutex
);
590 ret
= para_select(max_fileno
+ 1, readfds
, writefds
, timeout_tv
);
591 mutex_lock(mmd_mutex
);
596 * The main function of para_server.
598 * \param argc Usual argument count.
599 * \param argv Usual argument vector.
601 * \return EXIT_SUCCESS or EXIT_FAILURE.
603 int main(int argc
, char *argv
[])
607 sched
.default_timeout
.tv_sec
= 1;
608 sched
.select_function
= server_select
;
610 server_init(argc
, argv
);
611 mutex_lock(mmd_mutex
);
612 ret
= schedule(&sched
);
613 sched_shutdown(&sched
);
615 lls_free_parse_result(server_lpr
, CMD_PTR
);
616 if (server_lpr
!= cmdline_lpr
)
617 lls_free_parse_result(cmdline_lpr
, CMD_PTR
);
619 PARA_EMERG_LOG("%s\n", para_strerror(-ret
));
620 exit(ret
< 0? EXIT_FAILURE
: EXIT_SUCCESS
);