net: Remove networking headers from para.h.
[paraslash.git] / server.c
1 /*
2 * Copyright (C) 1997-2013 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 /**
11 * \mainpage Starting points for getting an overview:
12 *
13 * - The main programs: \ref server.c, \ref audiod.c, \ref client.c,
14 * \ref audioc.c, \ref afh.c, \ref play.c,
15 * - Server: \ref server_command, \ref sender,
16 * - Audio file selector: \ref audio_format_handler, \ref afs_table,
17 * - Client: \ref receiver, \ref receiver_node, \ref filter,
18 * \ref filter_node, \ref writer_node.
19 *
20 *
21 * The gory details, listed by topic:
22 *
23 * - Audio format handlers: \ref send_common.c \ref mp3_afh.c,
24 * \ref ogg_afh.c, \ref aac_afh.c, \ref wma_afh.c, \ref spx_afh.c
25 * - Decoders: \ref mp3dec_filter.c, \ref oggdec_filter.c,
26 * \ref aacdec_filter.c, \ref wmadec_filter.c, spxdec_filter.c,
27 * \ref flacdec_filter.c,
28 * - Volume normalizer: \ref compress_filter.c,
29 * - Output: \ref alsa_write.c, \ref osx_write.c, \ref oss_write.c,
30 * - http: \ref http_recv.c, \ref http_send.c,
31 * - udp: \ref udp_recv.c, \ref udp_send.c,
32 * - dccp: \ref dccp_recv.c, \ref dccp_send.c,
33 * - Audio file selector: \ref afs.c, \ref aft.c, \ref mood.c,
34 * - Afs structures: \ref afs_table, \ref audio_file_data,
35 * \ref afs_info \ref afh_info,
36 * - Afs tables: \ref aft.c, \ref mood.c, \ref playlist.c,
37 * \ref attribute.c, \ref score.c,
38 * - The virtual streaming system: \ref vss.c, \ref chunk_queue.c.
39 *
40 * Lower levels:
41 *
42 * - Scheduling: \ref sched.c, \ref sched.h,
43 * - Networking: \ref net.c,
44 * - File descriptors: \ref fd.c,
45 * - Signals: \ref signal.c,
46 * - Daemons: \ref daemon.c,
47 * - Strings: \ref string.c, \ref string.h,
48 * - Time: \ref time.c,
49 * - Spawning processes: \ref exec.c,
50 * - Inter process communication: \ref ipc.c,
51 * - Blob tables: \ref blob.c,
52 * - The error subsystem: \ref error.h.
53 * - Access control for paraslash senders: \ref acl.c, \ref acl.h.
54 * - Internal crypto API: \ref crypt.h.
55 * - interactive sessions (libreadline): \ref interactive.c.
56 *
57 * Low-level data structures:
58 *
59 * - Doubly linked lists: \ref list.h,
60 * - Ring buffer: \ref ringbuffer.c, \ref ringbuffer.h,
61 * - openssl: \ref crypt.c
62 * - libgcrypt: \ref gcrypt.c
63 * - Forward error correction: \ref fec.c.
64 */
65
66 #include <netinet/in.h>
67 #include <sys/socket.h>
68 #include <signal.h>
69 #include <regex.h>
70 #include <osl.h>
71 #include <sys/types.h>
72 #include <arpa/inet.h>
73 #include <sys/un.h>
74 #include <netdb.h>
75
76 #include "para.h"
77 #include "error.h"
78 #include "crypt.h"
79 #include "server.cmdline.h"
80 #include "afh.h"
81 #include "string.h"
82 #include "afs.h"
83 #include "server.h"
84 #include "list.h"
85 #include "send.h"
86 #include "sched.h"
87 #include "vss.h"
88 #include "config.h"
89 #include "close_on_fork.h"
90 #include "net.h"
91 #include "daemon.h"
92 #include "ipc.h"
93 #include "fd.h"
94 #include "signal.h"
95 #include "user_list.h"
96 #include "color.h"
97 #include "ggo.h"
98 #include "version.h"
99
100 __printf_2_3 void (*para_log)(int, const char*, ...) = daemon_log;
101
102 /** Define the array of error lists needed by para_server. */
103 INIT_SERVER_ERRLISTS;
104
105 /** Shut down non-authorized connections after that many seconds. */
106 #define ALARM_TIMEOUT 10
107
108 /**
109 * Pointer to shared memory area for communication between para_server
110 * and its children. Exported to vss.c. command.c and to afs.
111 */
112 struct misc_meta_data *mmd;
113
114 /**
115 * The configuration of para_server
116 *
117 * It also contains the options for the audio file selector, audio format
118 * handler and all supported senders.
119 */
120 struct server_args_info conf;
121
122 /** A random value used in child context for authentication. */
123 uint32_t afs_socket_cookie;
124
125 /** The mutex protecting the shared memory area containing the mmd struct. */
126 int mmd_mutex;
127
128 /** The file containing user information (public key, permissions). */
129 static char *user_list_file = NULL;
130
131 static struct sched sched;
132
133 /** The task responsible for server command handling. */
134 struct server_command_task {
135 /** TCP port on which para_server listens for connections. */
136 int listen_fd;
137 /** Copied from para_server's main function. */
138 int argc;
139 /** Argument vector passed to para_server's main function. */
140 char **argv;
141 /** The command task structure for scheduling. */
142 struct task task;
143 };
144
145 static int want_colors(void)
146 {
147 if (conf.color_arg == color_arg_no)
148 return 0;
149 if (conf.color_arg == color_arg_yes)
150 return 1;
151 if (conf.logfile_given)
152 return 0;
153 return isatty(STDERR_FILENO);
154 }
155
156 static void init_colors_or_die(void)
157 {
158 int i;
159
160 if (!want_colors())
161 return;
162 daemon_set_flag(DF_COLOR_LOG);
163 daemon_set_default_log_colors();
164 for (i = 0; i < conf.log_color_given; i++)
165 daemon_set_log_color_or_die(conf.log_color_arg[i]);
166 }
167
168 /*
169 * setup shared memory area and get mutex for locking
170 */
171 static void init_ipc_or_die(void)
172 {
173 void *shm;
174 int shmid, ret = shm_new(sizeof(struct misc_meta_data));
175
176 if (ret < 0)
177 goto err_out;
178 shmid = ret;
179 ret = shm_attach(shmid, ATTACH_RW, &shm);
180 shm_destroy(shmid);
181 if (ret < 0)
182 goto err_out;
183 mmd = shm;
184
185 ret = mutex_new();
186 if (ret < 0)
187 goto err_out;
188 mmd_mutex = ret;
189
190 mmd->num_played = 0;
191 mmd->num_commands = 0;
192 mmd->events = 0;
193 mmd->num_connects = 0;
194 mmd->active_connections = 0;
195 mmd->vss_status_flags = VSS_NEXT;
196 mmd->new_vss_status_flags = VSS_NEXT;
197 return;
198 err_out:
199 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
200 exit(EXIT_FAILURE);
201 }
202
203 /**
204 * (Re-)read the server configuration files.
205 *
206 * \param override Passed to gengetopt to activate the override feature.
207 *
208 * This function also re-opens the logfile and sets the global \a
209 * user_list_file variable.
210 */
211 void parse_config_or_die(int override)
212 {
213 char *home = para_homedir();
214 int ret;
215 char *cf;
216
217 daemon_close_log();
218 if (conf.config_file_given)
219 cf = para_strdup(conf.config_file_arg);
220 else
221 cf = make_message("%s/.paraslash/server.conf", home);
222 free(user_list_file);
223 if (!conf.user_list_given)
224 user_list_file = make_message("%s/.paraslash/server.users", home);
225 else
226 user_list_file = para_strdup(conf.user_list_arg);
227 ret = file_exists(cf);
228 if (conf.config_file_given && !ret) {
229 ret = -1;
230 PARA_EMERG_LOG("can not read config file %s\n", cf);
231 goto out;
232 }
233 if (ret) {
234 int tmp = conf.daemon_given;
235 struct server_cmdline_parser_params params = {
236 .override = override,
237 .initialize = 0,
238 .check_required = 1,
239 .check_ambiguity = 0,
240 .print_errors = !conf.daemon_given
241 };
242 server_cmdline_parser_config_file(cf, &conf, &params);
243 daemon_set_loglevel(conf.loglevel_arg);
244 conf.daemon_given = tmp;
245 }
246 if (conf.logfile_given) {
247 daemon_set_logfile(conf.logfile_arg);
248 daemon_open_log_or_die();
249 }
250 init_colors_or_die();
251 daemon_set_flag(DF_LOG_PID);
252 daemon_set_flag(DF_LOG_LL);
253 daemon_set_flag(DF_LOG_TIME);
254 if (conf.log_timing_given)
255 daemon_set_flag(DF_LOG_TIMING);
256 ret = 1;
257 out:
258 free(cf);
259 free(home);
260 if (ret > 0)
261 return;
262 free(user_list_file);
263 user_list_file = NULL;
264 exit(EXIT_FAILURE);
265 }
266
267 static void signal_pre_select(struct sched *s, struct task *t)
268 {
269 struct signal_task *st = container_of(t, struct signal_task, task);
270 para_fd_set(st->fd, &s->rfds, &s->max_fileno);
271 }
272
273 /*
274 * called when server gets SIGHUP or when client invokes hup command.
275 */
276 static void handle_sighup(void)
277 {
278 PARA_NOTICE_LOG("SIGHUP\n");
279 parse_config_or_die(1); /* reopens log */
280 init_user_list(user_list_file); /* reload user list */
281 if (mmd->afs_pid)
282 kill(mmd->afs_pid, SIGHUP);
283 }
284
285 static int signal_post_select(struct sched *s, __a_unused struct task *t)
286 {
287 int signum = para_next_signal(&s->rfds);
288
289 switch (signum) {
290 case 0:
291 return 0;
292 case SIGHUP:
293 handle_sighup();
294 break;
295 case SIGCHLD:
296 for (;;) {
297 pid_t pid;
298 int ret = para_reap_child(&pid);
299 if (ret <= 0)
300 break;
301 if (pid != mmd->afs_pid)
302 continue;
303 PARA_EMERG_LOG("fatal: afs died\n");
304 kill(0, SIGTERM);
305 goto cleanup;
306 }
307 break;
308 /* die on sigint/sigterm. Kill all children too. */
309 case SIGINT:
310 case SIGTERM:
311 PARA_EMERG_LOG("terminating on signal %d\n", signum);
312 kill(0, SIGTERM);
313 /*
314 * We must wait for afs because afs catches SIGINT/SIGTERM.
315 * Before reacting to the signal, afs might want to use the
316 * shared memory area and the mmd mutex. If we destroy this
317 * mutex too early and afs tries to lock the shared memory
318 * area, the call to mutex_lock() will fail and terminate the
319 * afs process. This leads to dirty osl tables.
320 *
321 * There's no such problem with the other children of the
322 * server process (the command handlers) as these reset their
323 * SIGINT/SIGTERM handlers to the default action, i.e. these
324 * processes get killed immediately by the above kill().
325 */
326 PARA_INFO_LOG("waiting for afs (pid %d) to die\n",
327 (int)mmd->afs_pid);
328 waitpid(mmd->afs_pid, NULL, 0);
329 cleanup:
330 free(mmd->afd.afhi.chunk_table);
331 close_listed_fds();
332 mutex_destroy(mmd_mutex);
333 shm_detach(mmd);
334 exit(EXIT_FAILURE);
335 }
336 return 0;
337 }
338
339 static void init_signal_task(void)
340 {
341 static struct signal_task signal_task_struct,
342 *st = &signal_task_struct;
343
344 st->task.pre_select = signal_pre_select;
345 st->task.post_select = signal_post_select;
346 sprintf(st->task.status, "signal task");
347
348 PARA_NOTICE_LOG("setting up signal handling\n");
349 st->fd = para_signal_init(); /* always successful */
350 para_install_sighandler(SIGINT);
351 para_install_sighandler(SIGTERM);
352 para_install_sighandler(SIGHUP);
353 para_install_sighandler(SIGCHLD);
354 para_sigaction(SIGPIPE, SIG_IGN);
355 add_close_on_fork_list(st->fd);
356 register_task(&sched, &st->task);
357 }
358
359 static void command_pre_select(struct sched *s, struct task *t)
360 {
361 struct server_command_task *sct = container_of(t, struct server_command_task, task);
362 para_fd_set(sct->listen_fd, &s->rfds, &s->max_fileno);
363 }
364
365 static int command_post_select(struct sched *s, struct task *t)
366 {
367 struct server_command_task *sct = container_of(t, struct server_command_task, task);
368
369 int new_fd, ret, i;
370 char *peer_name;
371 pid_t child_pid;
372 uint32_t *chunk_table;
373
374 ret = para_accept(sct->listen_fd, &s->rfds, NULL, 0, &new_fd);
375 if (ret <= 0)
376 goto out;
377 peer_name = remote_name(new_fd);
378 PARA_INFO_LOG("got connection from %s, forking\n", peer_name);
379 mmd->num_connects++;
380 mmd->active_connections++;
381 /*
382 * The chunk table is a pointer located in the mmd struct that points
383 * to dynamically allocated memory, i.e. it must be freed by the parent
384 * and the child. However, as the mmd struct is in a shared memory
385 * area, there's no guarantee that after the fork this pointer is still
386 * valid in child context. As it is not used in the child anyway, we
387 * save it to a local variable before the fork and free the memory via
388 * that copy in the child directly after the fork.
389 */
390 chunk_table = mmd->afd.afhi.chunk_table;
391 child_pid = fork();
392 if (child_pid < 0) {
393 ret = -ERRNO_TO_PARA_ERROR(errno);
394 goto out;
395 }
396 if (child_pid) {
397 /* avoid problems with non-fork-safe PRNGs */
398 unsigned char buf[16];
399 get_random_bytes_or_die(buf, sizeof(buf));
400 close(new_fd);
401 /* parent keeps accepting connections */
402 return 0;
403 }
404 /* mmd might already have changed at this point */
405 free(chunk_table);
406 alarm(ALARM_TIMEOUT);
407 close_listed_fds();
408 para_signal_shutdown();
409 /*
410 * put info on who we are serving into argv[0] to make
411 * client ip visible in top/ps
412 */
413 for (i = sct->argc - 1; i >= 0; i--)
414 memset(sct->argv[i], 0, strlen(sct->argv[i]));
415 sprintf(sct->argv[0], "para_server (serving %s)", peer_name);
416 handle_connect(new_fd, peer_name);
417 /* never reached*/
418 out:
419 if (ret < 0)
420 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
421 return 0;
422 }
423
424 static void init_server_command_task(int argc, char **argv)
425 {
426 int ret;
427 static struct server_command_task server_command_task_struct,
428 *sct = &server_command_task_struct;
429
430 PARA_NOTICE_LOG("initializing tcp command socket\n");
431 sct->task.pre_select = command_pre_select;
432 sct->task.post_select = command_post_select;
433 sct->argc = argc;
434 sct->argv = argv;
435 ret = para_listen_simple(IPPROTO_TCP, conf.port_arg);
436 if (ret < 0)
437 goto err;
438 sct->listen_fd = ret;
439 ret = mark_fd_nonblocking(sct->listen_fd);
440 if (ret < 0)
441 goto err;
442 add_close_on_fork_list(sct->listen_fd); /* child doesn't need the listener */
443 sprintf(sct->task.status, "server command task");
444 register_task(&sched, &sct->task);
445 return;
446 err:
447 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
448 exit(EXIT_FAILURE);
449 }
450
451 static int init_afs(int argc, char **argv)
452 {
453 int ret, afs_server_socket[2];
454 pid_t afs_pid;
455
456 ret = socketpair(PF_UNIX, SOCK_DGRAM, 0, afs_server_socket);
457 if (ret < 0)
458 exit(EXIT_FAILURE);
459 get_random_bytes_or_die((unsigned char *)&afs_socket_cookie,
460 sizeof(afs_socket_cookie));
461 afs_pid = fork();
462 if (afs_pid < 0)
463 exit(EXIT_FAILURE);
464 if (afs_pid == 0) { /* child (afs) */
465 int i;
466 for (i = argc - 1; i >= 0; i--)
467 memset(argv[i], 0, strlen(argv[i]));
468 sprintf(argv[0], "para_server (afs)");
469 close(afs_server_socket[0]);
470 afs_init(afs_socket_cookie, afs_server_socket[1]);
471 }
472 mmd->afs_pid = afs_pid;
473 close(afs_server_socket[1]);
474 ret = mark_fd_nonblocking(afs_server_socket[0]);
475 if (ret < 0)
476 exit(EXIT_FAILURE);
477 add_close_on_fork_list(afs_server_socket[0]);
478 PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
479 afs_server_socket[0], (unsigned) afs_socket_cookie);
480 return afs_server_socket[0];
481 }
482
483 __noreturn static void print_help_and_die(void)
484 {
485 struct ggo_help h = DEFINE_GGO_HELP(server);
486 bool d = conf.detailed_help_given;
487
488 ggo_print_help(&h, d? GPH_STANDARD_FLAGS_DETAILED : GPH_STANDARD_FLAGS);
489 exit(0);
490 }
491
492 static void server_init(int argc, char **argv)
493 {
494 struct server_cmdline_parser_params params = {
495 .override = 0,
496 .initialize = 1,
497 .check_required = 0,
498 .check_ambiguity = 0,
499 .print_errors = 1
500 };
501 int afs_socket;
502
503 valid_fd_012();
504 init_random_seed_or_die();
505 /* parse command line options */
506 server_cmdline_parser_ext(argc, argv, &conf, &params);
507 daemon_set_loglevel(conf.loglevel_arg);
508 version_handle_flag("server", conf.version_given);
509 if (conf.help_given || conf.detailed_help_given)
510 print_help_and_die();
511 drop_privileges_or_die(conf.user_arg, conf.group_arg);
512 /* parse config file, open log and set defaults */
513 parse_config_or_die(0);
514 log_welcome("para_server");
515 init_ipc_or_die(); /* init mmd struct and mmd->lock */
516 /* make sure, the global now pointer is uptodate */
517 clock_get_realtime(now);
518 set_server_start_time(now);
519 init_user_list(user_list_file);
520 /* become daemon */
521 if (conf.daemon_given)
522 daemonize(true /* parent waits for SIGTERM */);
523 PARA_NOTICE_LOG("initializing audio format handlers\n");
524 afh_init();
525
526 /*
527 * Although afs uses its own signal handling we must ignore SIGUSR1
528 * _before_ the afs child process gets born by init_afs() below. It's
529 * racy to do this in the child because the parent might send SIGUSR1
530 * before the child gets a chance to ignore this signal -- only the
531 * good die young.
532 */
533 para_sigaction(SIGUSR1, SIG_IGN);
534 /*
535 * We have to block SIGCHLD before the afs process is being forked off.
536 * Otherwise, para_server does not notice if afs dies before the
537 * SIGCHLD handler has been installed for the parent process by
538 * init_signal_task() below.
539 */
540 para_block_signal(SIGCHLD);
541 PARA_NOTICE_LOG("initializing the audio file selector\n");
542 afs_socket = init_afs(argc, argv);
543 init_signal_task();
544 para_unblock_signal(SIGCHLD);
545 PARA_NOTICE_LOG("initializing virtual streaming system\n");
546 init_vss_task(afs_socket, &sched);
547 init_server_command_task(argc, argv);
548 if (conf.daemon_given)
549 kill(getppid(), SIGTERM);
550 PARA_NOTICE_LOG("server init complete\n");
551 }
552
553 static void status_refresh(void)
554 {
555 static int prev_uptime = -1, prev_events = -1;
556 int uptime = get_server_uptime(now);
557
558 if (prev_events != mmd->events)
559 goto out;
560 if (mmd->new_vss_status_flags != mmd->vss_status_flags)
561 goto out_inc_events;
562 if (uptime / 60 != prev_uptime / 60)
563 goto out_inc_events;
564 return;
565 out_inc_events:
566 mmd->events++;
567 out:
568 prev_uptime = uptime;
569 prev_events = mmd->events;
570 mmd->vss_status_flags = mmd->new_vss_status_flags;
571 PARA_DEBUG_LOG("%d events, forcing status update\n", mmd->events);
572 killpg(0, SIGUSR1);
573 }
574
575 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
576 struct timeval *timeout_tv)
577 {
578 int ret;
579
580 status_refresh();
581 mutex_unlock(mmd_mutex);
582 ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
583 mutex_lock(mmd_mutex);
584 return ret;
585 }
586
587 /**
588 * The main function of para_server.
589 *
590 * \param argc Usual argument count.
591 * \param argv Usual argument vector.
592 *
593 * \return EXIT_SUCCESS or EXIT_FAILURE.
594 */
595 int main(int argc, char *argv[])
596 {
597 int ret;
598
599 sched.default_timeout.tv_sec = 1;
600 sched.select_function = server_select;
601
602 server_init(argc, argv);
603 mutex_lock(mmd_mutex);
604 ret = schedule(&sched);
605 if (ret < 0) {
606 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
607 exit(EXIT_FAILURE);
608 }
609 exit(EXIT_SUCCESS);
610 }