sched: Dont use fixed-size buffer for task names.
[paraslash.git] / server.c
1 /*
2 * Copyright (C) 1997-2014 Andre Noll <maan@systemlinux.org>
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 static int want_colors(void)
117 {
118 if (conf.color_arg == color_arg_no)
119 return 0;
120 if (conf.color_arg == color_arg_yes)
121 return 1;
122 if (conf.logfile_given)
123 return 0;
124 return isatty(STDERR_FILENO);
125 }
126
127 static void init_colors_or_die(void)
128 {
129 int i;
130
131 if (!want_colors())
132 return;
133 daemon_set_flag(DF_COLOR_LOG);
134 daemon_set_default_log_colors();
135 for (i = 0; i < conf.log_color_given; i++)
136 daemon_set_log_color_or_die(conf.log_color_arg[i]);
137 }
138
139 /*
140 * setup shared memory area and get mutex for locking
141 */
142 static void init_ipc_or_die(void)
143 {
144 void *shm;
145 int shmid, ret = shm_new(sizeof(struct misc_meta_data));
146
147 if (ret < 0)
148 goto err_out;
149 shmid = ret;
150 ret = shm_attach(shmid, ATTACH_RW, &shm);
151 shm_destroy(shmid);
152 if (ret < 0)
153 goto err_out;
154 mmd = shm;
155
156 ret = mutex_new();
157 if (ret < 0)
158 goto err_out;
159 mmd_mutex = ret;
160
161 mmd->num_played = 0;
162 mmd->num_commands = 0;
163 mmd->events = 0;
164 mmd->num_connects = 0;
165 mmd->active_connections = 0;
166 mmd->vss_status_flags = VSS_NEXT;
167 mmd->new_vss_status_flags = VSS_NEXT;
168 return;
169 err_out:
170 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
171 exit(EXIT_FAILURE);
172 }
173
174 /**
175 * (Re-)read the server configuration files.
176 *
177 * \param override Passed to gengetopt to activate the override feature.
178 *
179 * This function also re-opens the logfile and sets the global \a
180 * user_list_file variable.
181 */
182 void parse_config_or_die(int override)
183 {
184 char *home = para_homedir();
185 int ret;
186 char *cf;
187
188 daemon_close_log();
189 if (conf.config_file_given)
190 cf = para_strdup(conf.config_file_arg);
191 else
192 cf = make_message("%s/.paraslash/server.conf", home);
193 free(user_list_file);
194 if (!conf.user_list_given)
195 user_list_file = make_message("%s/.paraslash/server.users", home);
196 else
197 user_list_file = para_strdup(conf.user_list_arg);
198 ret = file_exists(cf);
199 if (conf.config_file_given && !ret) {
200 ret = -1;
201 PARA_EMERG_LOG("can not read config file %s\n", cf);
202 goto out;
203 }
204 if (ret) {
205 int tmp = conf.daemon_given;
206 struct server_cmdline_parser_params params = {
207 .override = override,
208 .initialize = 0,
209 .check_required = 1,
210 .check_ambiguity = 0,
211 .print_errors = !conf.daemon_given
212 };
213 server_cmdline_parser_config_file(cf, &conf, &params);
214 daemon_set_loglevel(conf.loglevel_arg);
215 conf.daemon_given = tmp;
216 }
217 if (conf.logfile_given) {
218 daemon_set_logfile(conf.logfile_arg);
219 daemon_open_log_or_die();
220 }
221 init_colors_or_die();
222 daemon_set_flag(DF_LOG_PID);
223 daemon_set_flag(DF_LOG_LL);
224 daemon_set_flag(DF_LOG_TIME);
225 if (conf.log_timing_given)
226 daemon_set_flag(DF_LOG_TIMING);
227 ret = 1;
228 out:
229 free(cf);
230 free(home);
231 if (ret > 0)
232 return;
233 free(user_list_file);
234 user_list_file = NULL;
235 exit(EXIT_FAILURE);
236 }
237
238 static void signal_pre_select(struct sched *s, struct task *t)
239 {
240 struct signal_task *st = task_context(t);
241 para_fd_set(st->fd, &s->rfds, &s->max_fileno);
242 }
243
244 /*
245 * called when server gets SIGHUP or when client invokes hup command.
246 */
247 static void handle_sighup(void)
248 {
249 PARA_NOTICE_LOG("SIGHUP\n");
250 parse_config_or_die(1); /* reopens log */
251 init_user_list(user_list_file); /* reload user list */
252 if (mmd->afs_pid)
253 kill(mmd->afs_pid, SIGHUP);
254 }
255
256 static int signal_post_select(struct sched *s, __a_unused struct task *t)
257 {
258 int signum = para_next_signal(&s->rfds);
259
260 switch (signum) {
261 case 0:
262 return 0;
263 case SIGHUP:
264 handle_sighup();
265 break;
266 case SIGCHLD:
267 for (;;) {
268 pid_t pid;
269 int ret = para_reap_child(&pid);
270 if (ret <= 0)
271 break;
272 if (pid != mmd->afs_pid)
273 continue;
274 PARA_EMERG_LOG("fatal: afs died\n");
275 kill(0, SIGTERM);
276 goto cleanup;
277 }
278 break;
279 /* die on sigint/sigterm. Kill all children too. */
280 case SIGINT:
281 case SIGTERM:
282 PARA_EMERG_LOG("terminating on signal %d\n", signum);
283 kill(0, SIGTERM);
284 /*
285 * We must wait for afs because afs catches SIGINT/SIGTERM.
286 * Before reacting to the signal, afs might want to use the
287 * shared memory area and the mmd mutex. If we destroy this
288 * mutex too early and afs tries to lock the shared memory
289 * area, the call to mutex_lock() will fail and terminate the
290 * afs process. This leads to dirty osl tables.
291 *
292 * There's no such problem with the other children of the
293 * server process (the command handlers) as these reset their
294 * SIGINT/SIGTERM handlers to the default action, i.e. these
295 * processes get killed immediately by the above kill().
296 */
297 PARA_INFO_LOG("waiting for afs (pid %d) to die\n",
298 (int)mmd->afs_pid);
299 waitpid(mmd->afs_pid, NULL, 0);
300 cleanup:
301 free(mmd->afd.afhi.chunk_table);
302 close_listed_fds();
303 mutex_destroy(mmd_mutex);
304 shm_detach(mmd);
305 exit(EXIT_FAILURE);
306 }
307 return 0;
308 }
309
310 static void init_signal_task(void)
311 {
312 static struct signal_task signal_task_struct,
313 *st = &signal_task_struct;
314
315 PARA_NOTICE_LOG("setting up signal handling\n");
316 st->fd = para_signal_init(); /* always successful */
317 para_install_sighandler(SIGINT);
318 para_install_sighandler(SIGTERM);
319 para_install_sighandler(SIGHUP);
320 para_install_sighandler(SIGCHLD);
321 para_sigaction(SIGPIPE, SIG_IGN);
322 add_close_on_fork_list(st->fd);
323 st->task = task_register(&(struct task_info) {
324 .name = "signal",
325 .pre_select = signal_pre_select,
326 .post_select = signal_post_select,
327 .context = st,
328
329 }, &sched);
330 }
331
332 static void command_pre_select(struct sched *s, struct task *t)
333 {
334 struct server_command_task *sct = task_context(t);
335 para_fd_set(sct->listen_fd, &s->rfds, &s->max_fileno);
336 }
337
338 static int command_post_select(struct sched *s, struct task *t)
339 {
340 struct server_command_task *sct = task_context(t);
341
342 int new_fd, ret, i;
343 char *peer_name;
344 pid_t child_pid;
345 uint32_t *chunk_table;
346
347 ret = para_accept(sct->listen_fd, &s->rfds, NULL, 0, &new_fd);
348 if (ret <= 0)
349 goto out;
350 peer_name = remote_name(new_fd);
351 PARA_INFO_LOG("got connection from %s, forking\n", peer_name);
352 mmd->num_connects++;
353 mmd->active_connections++;
354 /*
355 * The chunk table is a pointer located in the mmd struct that points
356 * to dynamically allocated memory, i.e. it must be freed by the parent
357 * and the child. However, as the mmd struct is in a shared memory
358 * area, there's no guarantee that after the fork this pointer is still
359 * valid in child context. As it is not used in the child anyway, we
360 * save it to a local variable before the fork and free the memory via
361 * that copy in the child directly after the fork.
362 */
363 chunk_table = mmd->afd.afhi.chunk_table;
364 child_pid = fork();
365 if (child_pid < 0) {
366 ret = -ERRNO_TO_PARA_ERROR(errno);
367 goto out;
368 }
369 if (child_pid) {
370 /* avoid problems with non-fork-safe PRNGs */
371 unsigned char buf[16];
372 get_random_bytes_or_die(buf, sizeof(buf));
373 close(new_fd);
374 /* parent keeps accepting connections */
375 return 0;
376 }
377 /* mmd might already have changed at this point */
378 free(chunk_table);
379 alarm(ALARM_TIMEOUT);
380 close_listed_fds();
381 para_signal_shutdown();
382 /*
383 * put info on who we are serving into argv[0] to make
384 * client ip visible in top/ps
385 */
386 for (i = sct->argc - 1; i >= 0; i--)
387 memset(sct->argv[i], 0, strlen(sct->argv[i]));
388 sprintf(sct->argv[0], "para_server (serving %s)", peer_name);
389 handle_connect(new_fd, peer_name);
390 /* never reached*/
391 out:
392 if (ret < 0)
393 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
394 return 0;
395 }
396
397 static void init_server_command_task(int argc, char **argv)
398 {
399 int ret;
400 static struct server_command_task server_command_task_struct,
401 *sct = &server_command_task_struct;
402
403 PARA_NOTICE_LOG("initializing tcp command socket\n");
404 sct->argc = argc;
405 sct->argv = argv;
406 ret = para_listen_simple(IPPROTO_TCP, conf.port_arg);
407 if (ret < 0)
408 goto err;
409 sct->listen_fd = ret;
410 ret = mark_fd_nonblocking(sct->listen_fd);
411 if (ret < 0)
412 goto err;
413 add_close_on_fork_list(sct->listen_fd); /* child doesn't need the listener */
414 sct->task = task_register(&(struct task_info) {
415 .name = "server command",
416 .pre_select = command_pre_select,
417 .post_select = command_post_select,
418 .context = sct,
419 }, &sched);
420 return;
421 err:
422 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
423 exit(EXIT_FAILURE);
424 }
425
426 static int init_afs(int argc, char **argv)
427 {
428 int ret, afs_server_socket[2];
429 pid_t afs_pid;
430
431 ret = socketpair(PF_UNIX, SOCK_DGRAM, 0, afs_server_socket);
432 if (ret < 0)
433 exit(EXIT_FAILURE);
434 get_random_bytes_or_die((unsigned char *)&afs_socket_cookie,
435 sizeof(afs_socket_cookie));
436 afs_pid = fork();
437 if (afs_pid < 0)
438 exit(EXIT_FAILURE);
439 if (afs_pid == 0) { /* child (afs) */
440 int i;
441 for (i = argc - 1; i >= 0; i--)
442 memset(argv[i], 0, strlen(argv[i]));
443 sprintf(argv[0], "para_server (afs)");
444 close(afs_server_socket[0]);
445 afs_init(afs_socket_cookie, afs_server_socket[1]);
446 }
447 mmd->afs_pid = afs_pid;
448 close(afs_server_socket[1]);
449 ret = mark_fd_nonblocking(afs_server_socket[0]);
450 if (ret < 0)
451 exit(EXIT_FAILURE);
452 add_close_on_fork_list(afs_server_socket[0]);
453 PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
454 afs_server_socket[0], (unsigned) afs_socket_cookie);
455 return afs_server_socket[0];
456 }
457
458 __noreturn static void print_help_and_die(void)
459 {
460 struct ggo_help h = DEFINE_GGO_HELP(server);
461 bool d = conf.detailed_help_given;
462
463 ggo_print_help(&h, d? GPH_STANDARD_FLAGS_DETAILED : GPH_STANDARD_FLAGS);
464 exit(0);
465 }
466
467 static void server_init(int argc, char **argv)
468 {
469 struct server_cmdline_parser_params params = {
470 .override = 0,
471 .initialize = 1,
472 .check_required = 0,
473 .check_ambiguity = 0,
474 .print_errors = 1
475 };
476 int afs_socket;
477
478 valid_fd_012();
479 init_random_seed_or_die();
480 /* parse command line options */
481 server_cmdline_parser_ext(argc, argv, &conf, &params);
482 daemon_set_loglevel(conf.loglevel_arg);
483 version_handle_flag("server", conf.version_given);
484 if (conf.help_given || conf.detailed_help_given)
485 print_help_and_die();
486 drop_privileges_or_die(conf.user_arg, conf.group_arg);
487 /* parse config file, open log and set defaults */
488 parse_config_or_die(0);
489 log_welcome("para_server");
490 init_ipc_or_die(); /* init mmd struct and mmd->lock */
491 /* make sure, the global now pointer is uptodate */
492 clock_get_realtime(now);
493 set_server_start_time(now);
494 init_user_list(user_list_file);
495 /* become daemon */
496 if (conf.daemon_given)
497 daemonize(true /* parent waits for SIGTERM */);
498 PARA_NOTICE_LOG("initializing audio format handlers\n");
499 afh_init();
500
501 /*
502 * Although afs uses its own signal handling we must ignore SIGUSR1
503 * _before_ the afs child process gets born by init_afs() below. It's
504 * racy to do this in the child because the parent might send SIGUSR1
505 * before the child gets a chance to ignore this signal -- only the
506 * good die young.
507 */
508 para_sigaction(SIGUSR1, SIG_IGN);
509 /*
510 * We have to block SIGCHLD before the afs process is being forked off.
511 * Otherwise, para_server does not notice if afs dies before the
512 * SIGCHLD handler has been installed for the parent process by
513 * init_signal_task() below.
514 */
515 para_block_signal(SIGCHLD);
516 PARA_NOTICE_LOG("initializing the audio file selector\n");
517 afs_socket = init_afs(argc, argv);
518 init_signal_task();
519 para_unblock_signal(SIGCHLD);
520 PARA_NOTICE_LOG("initializing virtual streaming system\n");
521 init_vss_task(afs_socket, &sched);
522 init_server_command_task(argc, argv);
523 if (conf.daemon_given)
524 kill(getppid(), SIGTERM);
525 PARA_NOTICE_LOG("server init complete\n");
526 }
527
528 static void status_refresh(void)
529 {
530 static int prev_uptime = -1, prev_events = -1;
531 int uptime = get_server_uptime(now);
532
533 if (prev_events != mmd->events)
534 goto out;
535 if (mmd->new_vss_status_flags != mmd->vss_status_flags)
536 goto out_inc_events;
537 if (uptime / 60 != prev_uptime / 60)
538 goto out_inc_events;
539 return;
540 out_inc_events:
541 mmd->events++;
542 out:
543 prev_uptime = uptime;
544 prev_events = mmd->events;
545 mmd->vss_status_flags = mmd->new_vss_status_flags;
546 PARA_DEBUG_LOG("%d events, forcing status update\n", mmd->events);
547 killpg(0, SIGUSR1);
548 }
549
550 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
551 struct timeval *timeout_tv)
552 {
553 int ret;
554
555 status_refresh();
556 mutex_unlock(mmd_mutex);
557 ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
558 mutex_lock(mmd_mutex);
559 return ret;
560 }
561
562 /**
563 * The main function of para_server.
564 *
565 * \param argc Usual argument count.
566 * \param argv Usual argument vector.
567 *
568 * \return EXIT_SUCCESS or EXIT_FAILURE.
569 */
570 int main(int argc, char *argv[])
571 {
572 int ret;
573
574 sched.default_timeout.tv_sec = 1;
575 sched.select_function = server_select;
576
577 server_init(argc, argv);
578 mutex_lock(mmd_mutex);
579 ret = schedule(&sched);
580 sched_shutdown(&sched);
581 if (ret < 0) {
582 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
583 exit(EXIT_FAILURE);
584 }
585 exit(EXIT_SUCCESS);
586 }