daemon: Introduce daemon_init_colors_or_die().
[paraslash.git] / server.c
1 /*
2 * Copyright (C) 1997 Andre Noll <maan@tuebingen.mpg.de>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file server.c Paraslash's main server. */
8
9 /**
10 * \mainpage Main data structures:
11 *
12 * - Server: \ref server_command, \ref sender,
13 * - Audio file selector: \ref afs_info, \ref afs_table,
14 * - Audio format handler: \ref audio_format_handler, \ref afh_info
15 * - Receivers/filters/writers: \ref receiver, \ref receiver_node,
16 * \ref filter, \ref filter_node, \ref writer_node, \ref writer.
17 *
18 * Selected APIs:
19 *
20 * - Scheduling: \ref sched.h,
21 * - Buffer trees: \ref buffer_tree.h,
22 * - Sideband API: \ref sideband.h,
23 * - Crypto: \ref crypt.h, \ref crypt_backend.h,
24 * - Error subsystem: \ref error.h, \ref error2.c,
25 * - Inter process communication: \ref ipc.h,
26 * - Forward error correction: \ref fec.h,
27 * - Daemons: \ref daemon.h,
28 * - Mixer API: \ref mix.h,
29 * - Interactive sessions: \ref interactive.h,
30 * - File descriptors: \ref fd.h,
31 * - Signals: \ref signal.h,
32 * - Networking: \ref net.h,
33 * - Time: \ref time.c,
34 * - Doubly linked lists: \ref list.h.
35 */
36
37 #include <netinet/in.h>
38 #include <sys/socket.h>
39 #include <signal.h>
40 #include <regex.h>
41 #include <osl.h>
42 #include <sys/types.h>
43 #include <arpa/inet.h>
44 #include <sys/un.h>
45 #include <netdb.h>
46
47 #include "para.h"
48 #include "error.h"
49 #include "crypt.h"
50 #include "server.cmdline.h"
51 #include "afh.h"
52 #include "string.h"
53 #include "afs.h"
54 #include "server.h"
55 #include "list.h"
56 #include "send.h"
57 #include "sched.h"
58 #include "vss.h"
59 #include "config.h"
60 #include "close_on_fork.h"
61 #include "net.h"
62 #include "daemon.h"
63 #include "ipc.h"
64 #include "fd.h"
65 #include "signal.h"
66 #include "user_list.h"
67 #include "color.h"
68 #include "ggo.h"
69 #include "version.h"
70
71 __printf_2_3 void (*para_log)(int, const char*, ...) = daemon_log;
72
73 /** Define the array of error lists needed by para_server. */
74 INIT_SERVER_ERRLISTS;
75
76 /** Shut down non-authorized connections after that many seconds. */
77 #define ALARM_TIMEOUT 10
78
79 /**
80 * Pointer to shared memory area for communication between para_server
81 * and its children. Exported to vss.c. command.c and to afs.
82 */
83 struct misc_meta_data *mmd;
84
85 /**
86 * The configuration of para_server
87 *
88 * It also contains the options for the audio file selector, audio format
89 * handler and all supported senders.
90 */
91 struct server_args_info conf;
92
93 /** A random value used in child context for authentication. */
94 uint32_t afs_socket_cookie;
95
96 /** The mutex protecting the shared memory area containing the mmd struct. */
97 int mmd_mutex;
98
99 /** The file containing user information (public key, permissions). */
100 static char *user_list_file = NULL;
101
102 static struct sched sched;
103
104 /** The task responsible for server command handling. */
105 struct server_command_task {
106 /** TCP port on which para_server listens for connections. */
107 int listen_fd;
108 /** Copied from para_server's main function. */
109 int argc;
110 /** Argument vector passed to para_server's main function. */
111 char **argv;
112 /** The command task structure for scheduling. */
113 struct task *task;
114 };
115
116 /**
117 * Return the list of tasks for the server process.
118 *
119 * This is called from \a com_tasks(). The helper is necessary since command
120 * handlers can not access the scheduler structure directly.
121 *
122 * \return A dynamically allocated string that must be freed by the caller.
123 */
124 char *server_get_tasks(void)
125 {
126 return get_task_list(&sched);
127 }
128
129 /*
130 * setup shared memory area and get mutex for locking
131 */
132 static void init_ipc_or_die(void)
133 {
134 void *shm;
135 int shmid, ret = shm_new(sizeof(struct misc_meta_data));
136
137 if (ret < 0)
138 goto err_out;
139 shmid = ret;
140 ret = shm_attach(shmid, ATTACH_RW, &shm);
141 shm_destroy(shmid);
142 if (ret < 0)
143 goto err_out;
144 mmd = shm;
145
146 ret = mutex_new();
147 if (ret < 0)
148 goto err_out;
149 mmd_mutex = ret;
150
151 mmd->num_played = 0;
152 mmd->num_commands = 0;
153 mmd->events = 0;
154 mmd->num_connects = 0;
155 mmd->active_connections = 0;
156 mmd->vss_status_flags = VSS_NEXT;
157 mmd->new_vss_status_flags = VSS_NEXT;
158 return;
159 err_out:
160 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
161 exit(EXIT_FAILURE);
162 }
163
164 /**
165 * (Re-)read the server configuration files.
166 *
167 * \param override Passed to gengetopt to activate the override feature.
168 *
169 * This function also re-opens the logfile and sets the global \a
170 * user_list_file variable.
171 */
172 void parse_config_or_die(int override)
173 {
174 char *home = para_homedir();
175 int ret;
176 char *cf;
177
178 daemon_close_log();
179 if (conf.config_file_given)
180 cf = para_strdup(conf.config_file_arg);
181 else
182 cf = make_message("%s/.paraslash/server.conf", home);
183 free(user_list_file);
184 if (!conf.user_list_given)
185 user_list_file = make_message("%s/.paraslash/server.users", home);
186 else
187 user_list_file = para_strdup(conf.user_list_arg);
188 ret = file_exists(cf);
189 if (conf.config_file_given && !ret) {
190 ret = -1;
191 PARA_EMERG_LOG("can not read config file %s\n", cf);
192 goto out;
193 }
194 if (ret) {
195 int tmp = conf.daemon_given;
196 struct server_cmdline_parser_params params = {
197 .override = override,
198 .initialize = 0,
199 .check_required = 1,
200 .check_ambiguity = 0,
201 .print_errors = !conf.daemon_given
202 };
203 server_cmdline_parser_config_file(cf, &conf, &params);
204 daemon_set_loglevel(conf.loglevel_arg);
205 conf.daemon_given = tmp;
206 }
207 if (conf.logfile_given) {
208 daemon_set_logfile(conf.logfile_arg);
209 daemon_open_log_or_die();
210 }
211
212 daemon_init_colors_or_die(conf.color_arg, color_arg_auto, color_arg_no,
213 conf.logfile_given, conf.log_color_arg, conf.log_color_given);
214 daemon_set_flag(DF_LOG_PID);
215 daemon_set_flag(DF_LOG_LL);
216 daemon_set_flag(DF_LOG_TIME);
217 if (conf.log_timing_given)
218 daemon_set_flag(DF_LOG_TIMING);
219 ret = 1;
220 out:
221 free(cf);
222 free(home);
223 if (ret > 0)
224 return;
225 free(user_list_file);
226 user_list_file = NULL;
227 exit(EXIT_FAILURE);
228 }
229
230 static void signal_pre_select(struct sched *s, void *context)
231 {
232 struct signal_task *st = context;
233 para_fd_set(st->fd, &s->rfds, &s->max_fileno);
234 }
235
236 /*
237 * called when server gets SIGHUP or when client invokes hup command.
238 */
239 static void handle_sighup(void)
240 {
241 PARA_NOTICE_LOG("SIGHUP\n");
242 parse_config_or_die(1); /* reopens log */
243 init_user_list(user_list_file); /* reload user list */
244 if (mmd->afs_pid)
245 kill(mmd->afs_pid, SIGHUP);
246 }
247
248 static int signal_post_select(struct sched *s, __a_unused void *context)
249 {
250 int signum = para_next_signal(&s->rfds);
251
252 switch (signum) {
253 case 0:
254 return 0;
255 case SIGHUP:
256 handle_sighup();
257 break;
258 case SIGCHLD:
259 for (;;) {
260 pid_t pid;
261 int ret = para_reap_child(&pid);
262 if (ret <= 0)
263 break;
264 if (pid != mmd->afs_pid)
265 continue;
266 PARA_EMERG_LOG("fatal: afs died\n");
267 kill(0, SIGTERM);
268 goto cleanup;
269 }
270 break;
271 /* die on sigint/sigterm. Kill all children too. */
272 case SIGINT:
273 case SIGTERM:
274 PARA_EMERG_LOG("terminating on signal %d\n", signum);
275 kill(0, SIGTERM);
276 /*
277 * We must wait for afs because afs catches SIGINT/SIGTERM.
278 * Before reacting to the signal, afs might want to use the
279 * shared memory area and the mmd mutex. If we destroy this
280 * mutex too early and afs tries to lock the shared memory
281 * area, the call to mutex_lock() will fail and terminate the
282 * afs process. This leads to dirty osl tables.
283 *
284 * There's no such problem with the other children of the
285 * server process (the command handlers) as these reset their
286 * SIGINT/SIGTERM handlers to the default action, i.e. these
287 * processes get killed immediately by the above kill().
288 */
289 PARA_INFO_LOG("waiting for afs (pid %d) to die\n",
290 (int)mmd->afs_pid);
291 waitpid(mmd->afs_pid, NULL, 0);
292 cleanup:
293 free(mmd->afd.afhi.chunk_table);
294 close_listed_fds();
295 mutex_destroy(mmd_mutex);
296 shm_detach(mmd);
297 exit(EXIT_FAILURE);
298 }
299 return 0;
300 }
301
302 static void init_signal_task(void)
303 {
304 static struct signal_task signal_task_struct,
305 *st = &signal_task_struct;
306
307 PARA_NOTICE_LOG("setting up signal handling\n");
308 st->fd = para_signal_init(); /* always successful */
309 para_install_sighandler(SIGINT);
310 para_install_sighandler(SIGTERM);
311 para_install_sighandler(SIGHUP);
312 para_install_sighandler(SIGCHLD);
313 para_sigaction(SIGPIPE, SIG_IGN);
314 add_close_on_fork_list(st->fd);
315 st->task = task_register(&(struct task_info) {
316 .name = "signal",
317 .pre_select = signal_pre_select,
318 .post_select = signal_post_select,
319 .context = st,
320
321 }, &sched);
322 }
323
324 static void command_pre_select(struct sched *s, void *context)
325 {
326 struct server_command_task *sct = context;
327 para_fd_set(sct->listen_fd, &s->rfds, &s->max_fileno);
328 }
329
330 static int command_post_select(struct sched *s, void *context)
331 {
332 struct server_command_task *sct = context;
333
334 int new_fd, ret, i;
335 char *peer_name;
336 pid_t child_pid;
337 uint32_t *chunk_table;
338
339 ret = para_accept(sct->listen_fd, &s->rfds, NULL, 0, &new_fd);
340 if (ret <= 0)
341 goto out;
342 peer_name = remote_name(new_fd);
343 PARA_INFO_LOG("got connection from %s, forking\n", peer_name);
344 mmd->num_connects++;
345 mmd->active_connections++;
346 /*
347 * The chunk table is a pointer located in the mmd struct that points
348 * to dynamically allocated memory, i.e. it must be freed by the parent
349 * and the child. However, as the mmd struct is in a shared memory
350 * area, there's no guarantee that after the fork this pointer is still
351 * valid in child context. As it is not used in the child anyway, we
352 * save it to a local variable before the fork and free the memory via
353 * that copy in the child directly after the fork.
354 */
355 chunk_table = mmd->afd.afhi.chunk_table;
356 child_pid = fork();
357 if (child_pid < 0) {
358 ret = -ERRNO_TO_PARA_ERROR(errno);
359 goto out;
360 }
361 if (child_pid) {
362 /* avoid problems with non-fork-safe PRNGs */
363 unsigned char buf[16];
364 get_random_bytes_or_die(buf, sizeof(buf));
365 close(new_fd);
366 /* parent keeps accepting connections */
367 return 0;
368 }
369 /* mmd might already have changed at this point */
370 free(chunk_table);
371 alarm(ALARM_TIMEOUT);
372 close_listed_fds();
373 para_signal_shutdown();
374 /*
375 * put info on who we are serving into argv[0] to make
376 * client ip visible in top/ps
377 */
378 for (i = sct->argc - 1; i >= 0; i--)
379 memset(sct->argv[i], 0, strlen(sct->argv[i]));
380 sprintf(sct->argv[0], "para_server (serving %s)", peer_name);
381 handle_connect(new_fd, peer_name);
382 /* never reached*/
383 out:
384 if (ret < 0)
385 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
386 return 0;
387 }
388
389 static void init_server_command_task(int argc, char **argv)
390 {
391 int ret;
392 static struct server_command_task server_command_task_struct,
393 *sct = &server_command_task_struct;
394
395 PARA_NOTICE_LOG("initializing tcp command socket\n");
396 sct->argc = argc;
397 sct->argv = argv;
398 ret = para_listen_simple(IPPROTO_TCP, conf.port_arg);
399 if (ret < 0)
400 goto err;
401 sct->listen_fd = ret;
402 ret = mark_fd_nonblocking(sct->listen_fd);
403 if (ret < 0)
404 goto err;
405 add_close_on_fork_list(sct->listen_fd); /* child doesn't need the listener */
406 sct->task = task_register(&(struct task_info) {
407 .name = "server command",
408 .pre_select = command_pre_select,
409 .post_select = command_post_select,
410 .context = sct,
411 }, &sched);
412 return;
413 err:
414 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
415 exit(EXIT_FAILURE);
416 }
417
418 static int init_afs(int argc, char **argv)
419 {
420 int ret, afs_server_socket[2];
421 pid_t afs_pid;
422
423 ret = socketpair(PF_UNIX, SOCK_DGRAM, 0, afs_server_socket);
424 if (ret < 0)
425 exit(EXIT_FAILURE);
426 get_random_bytes_or_die((unsigned char *)&afs_socket_cookie,
427 sizeof(afs_socket_cookie));
428 afs_pid = fork();
429 if (afs_pid < 0)
430 exit(EXIT_FAILURE);
431 if (afs_pid == 0) { /* child (afs) */
432 int i;
433 for (i = argc - 1; i >= 0; i--)
434 memset(argv[i], 0, strlen(argv[i]));
435 sprintf(argv[0], "para_server (afs)");
436 close(afs_server_socket[0]);
437 afs_init(afs_socket_cookie, afs_server_socket[1]);
438 }
439 mmd->afs_pid = afs_pid;
440 close(afs_server_socket[1]);
441 ret = mark_fd_nonblocking(afs_server_socket[0]);
442 if (ret < 0)
443 exit(EXIT_FAILURE);
444 add_close_on_fork_list(afs_server_socket[0]);
445 PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
446 afs_server_socket[0], (unsigned) afs_socket_cookie);
447 return afs_server_socket[0];
448 }
449
450 __noreturn static void print_help_and_die(void)
451 {
452 struct ggo_help h = DEFINE_GGO_HELP(server);
453 bool d = conf.detailed_help_given;
454
455 ggo_print_help(&h, d? GPH_STANDARD_FLAGS_DETAILED : GPH_STANDARD_FLAGS);
456 exit(0);
457 }
458
459 static void server_init(int argc, char **argv)
460 {
461 struct server_cmdline_parser_params params = {
462 .override = 0,
463 .initialize = 1,
464 .check_required = 0,
465 .check_ambiguity = 0,
466 .print_errors = 1
467 };
468 int afs_socket;
469
470 valid_fd_012();
471 init_random_seed_or_die();
472 /* parse command line options */
473 server_cmdline_parser_ext(argc, argv, &conf, &params);
474 daemon_set_loglevel(conf.loglevel_arg);
475 version_handle_flag("server", conf.version_given);
476 if (conf.help_given || conf.detailed_help_given)
477 print_help_and_die();
478 daemon_drop_privileges_or_die(conf.user_arg, conf.group_arg);
479 /* parse config file, open log and set defaults */
480 parse_config_or_die(0);
481 daemon_log_welcome("para_server");
482 init_ipc_or_die(); /* init mmd struct and mmd->lock */
483 daemon_set_start_time();
484 init_user_list(user_list_file);
485 /* become daemon */
486 if (conf.daemon_given)
487 daemonize(true /* parent waits for SIGTERM */);
488 PARA_NOTICE_LOG("initializing audio format handlers\n");
489 afh_init();
490
491 /*
492 * Although afs uses its own signal handling we must ignore SIGUSR1
493 * _before_ the afs child process gets born by init_afs() below. It's
494 * racy to do this in the child because the parent might send SIGUSR1
495 * before the child gets a chance to ignore this signal -- only the
496 * good die young.
497 */
498 para_sigaction(SIGUSR1, SIG_IGN);
499 /*
500 * We have to block SIGCHLD before the afs process is being forked off.
501 * Otherwise, para_server does not notice if afs dies before the
502 * SIGCHLD handler has been installed for the parent process by
503 * init_signal_task() below.
504 */
505 para_block_signal(SIGCHLD);
506 PARA_NOTICE_LOG("initializing the audio file selector\n");
507 afs_socket = init_afs(argc, argv);
508 init_signal_task();
509 para_unblock_signal(SIGCHLD);
510 PARA_NOTICE_LOG("initializing virtual streaming system\n");
511 init_vss_task(afs_socket, &sched);
512 init_server_command_task(argc, argv);
513 if (conf.daemon_given)
514 kill(getppid(), SIGTERM);
515 PARA_NOTICE_LOG("server init complete\n");
516 }
517
518 static void status_refresh(void)
519 {
520 static int prev_uptime = -1, prev_events = -1;
521 int uptime = daemon_get_uptime(now);
522
523 if (prev_events != mmd->events)
524 goto out;
525 if (mmd->new_vss_status_flags != mmd->vss_status_flags)
526 goto out_inc_events;
527 if (uptime / 60 != prev_uptime / 60)
528 goto out_inc_events;
529 return;
530 out_inc_events:
531 mmd->events++;
532 out:
533 prev_uptime = uptime;
534 prev_events = mmd->events;
535 mmd->vss_status_flags = mmd->new_vss_status_flags;
536 PARA_DEBUG_LOG("%d events, forcing status update\n", mmd->events);
537 killpg(0, SIGUSR1);
538 }
539
540 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
541 struct timeval *timeout_tv)
542 {
543 int ret;
544
545 status_refresh();
546 mutex_unlock(mmd_mutex);
547 ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
548 mutex_lock(mmd_mutex);
549 return ret;
550 }
551
552 /**
553 * The main function of para_server.
554 *
555 * \param argc Usual argument count.
556 * \param argv Usual argument vector.
557 *
558 * \return EXIT_SUCCESS or EXIT_FAILURE.
559 */
560 int main(int argc, char *argv[])
561 {
562 int ret;
563
564 sched.default_timeout.tv_sec = 1;
565 sched.select_function = server_select;
566
567 server_init(argc, argv);
568 mutex_lock(mmd_mutex);
569 ret = schedule(&sched);
570 sched_shutdown(&sched);
571 if (ret < 0) {
572 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
573 exit(EXIT_FAILURE);
574 }
575 exit(EXIT_SUCCESS);
576 }