f26abef5753204c4628c4183519f50f02b8f674e
[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 Paraslash API Reference
12 *
13 * Starting points for getting an overview:
14 *
15 *
16 * - The main programs: \ref server.c, \ref audiod.c, \ref client.c,
17 * \ref audioc.c, \ref afh.c, \ref play.c,
18 * - Server: \ref server_command, \ref sender,
19 * - Audio file selector: \ref audio_format_handler, \ref afs_table,
20 * - Client: \ref receiver, \ref receiver_node, \ref filter,
21 * \ref filter_node, \ref writer_node.
22 *
23 *
24 * The gory details, listed by topic:
25 *
26 * - Audio format handlers: \ref send_common.c \ref mp3_afh.c,
27 * \ref ogg_afh.c, \ref aac_afh.c, \ref wma_afh.c, \ref spx_afh.c
28 * - Decoders: \ref mp3dec_filter.c, \ref oggdec_filter.c,
29 * \ref aacdec_filter.c, \ref wmadec_filter.c, spxdec_filter.c,
30 * \ref flacdec_filter.c,
31 * - Volume normalizer: \ref compress_filter.c,
32 * - Output: \ref alsa_write.c, \ref osx_write.c, \ref oss_write.c,
33 * - http: \ref http_recv.c, \ref http_send.c,
34 * - udp: \ref udp_recv.c, \ref udp_send.c,
35 * - dccp: \ref dccp_recv.c, \ref dccp_send.c,
36 * - Audio file selector: \ref afs.c, \ref aft.c, \ref mood.c,
37 * - Afs structures: \ref afs_table, \ref audio_file_data,
38 * \ref afs_info \ref afh_info,
39 * - Afs tables: \ref aft.c, \ref mood.c, \ref playlist.c,
40 * \ref attribute.c, \ref score.c,
41 * - The virtual streaming system: \ref vss.c, \ref chunk_queue.c.
42 *
43 * Lower levels:
44 *
45 * - Scheduling: \ref sched.c, \ref sched.h,
46 * - Networking: \ref net.c,
47 * - File descriptors: \ref fd.c,
48 * - Signals: \ref signal.c,
49 * - Daemons: \ref daemon.c,
50 * - Strings: \ref string.c, \ref string.h,
51 * - Time: \ref time.c,
52 * - Spawning processes: \ref exec.c,
53 * - Inter process communication: \ref ipc.c,
54 * - Blob tables: \ref blob.c,
55 * - The error subsystem: \ref error.h.
56 * - Access control for paraslash senders: \ref acl.c, \ref acl.h.
57 * - Internal crypto API: \ref crypt.h.
58 * - interactive sessions (libreadline): \ref interactive.c.
59 *
60 * Low-level data structures:
61 *
62 * - Doubly linked lists: \ref list.h,
63 * - Ring buffer: \ref ringbuffer.c, \ref ringbuffer.h,
64 * - openssl: \ref crypt.c
65 * - libgcrypt: \ref gcrypt.c
66 * - Forward error correction: \ref fec.c.
67 */
68
69 #include <signal.h>
70 #include <regex.h>
71 #include <osl.h>
72
73 #include "para.h"
74 #include "error.h"
75 #include "crypt.h"
76 #include "server.cmdline.h"
77 #include "afh.h"
78 #include "string.h"
79 #include "afs.h"
80 #include "server.h"
81 #include "list.h"
82 #include "send.h"
83 #include "sched.h"
84 #include "vss.h"
85 #include "config.h"
86 #include "close_on_fork.h"
87 #include "net.h"
88 #include "daemon.h"
89 #include "ipc.h"
90 #include "fd.h"
91 #include "signal.h"
92 #include "user_list.h"
93 #include "color.h"
94 #include "ggo.h"
95 #include "version.h"
96
97 __printf_2_3 void (*para_log)(int, const char*, ...) = daemon_log;
98
99 /** Define the array of error lists needed by para_server. */
100 INIT_SERVER_ERRLISTS;
101
102 /** Shut down non-authorized connections after that many seconds. */
103 #define ALARM_TIMEOUT 10
104
105 /**
106 * Pointer to shared memory area for communication between para_server
107 * and its children. Exported to vss.c. command.c and to afs.
108 */
109 struct misc_meta_data *mmd;
110
111 /**
112 * The configuration of para_server
113 *
114 * It also contains the options for the audio file selector, audio format
115 * handler and all supported senders.
116 */
117 struct server_args_info conf;
118
119 /** A random value used in child context for authentication. */
120 uint32_t afs_socket_cookie;
121
122 /** The mutex protecting the shared memory area containing the mmd struct. */
123 int mmd_mutex;
124
125 /** The file containing user information (public key, permissions). */
126 static char *user_list_file = NULL;
127
128 static struct sched sched;
129
130 /** The task responsible for server command handling. */
131 struct server_command_task {
132 /** TCP port on which para_server listens for connections. */
133 int listen_fd;
134 /** Copied from para_server's main function. */
135 int argc;
136 /** Argument vector passed to para_server's main function. */
137 char **argv;
138 /** The command task structure for scheduling. */
139 struct task task;
140 };
141
142 static int want_colors(void)
143 {
144 if (conf.color_arg == color_arg_no)
145 return 0;
146 if (conf.color_arg == color_arg_yes)
147 return 1;
148 if (conf.logfile_given)
149 return 0;
150 return isatty(STDERR_FILENO);
151 }
152
153 static void init_colors_or_die(void)
154 {
155 int i;
156
157 if (!want_colors())
158 return;
159 daemon_set_flag(DF_COLOR_LOG);
160 daemon_set_default_log_colors();
161 for (i = 0; i < conf.log_color_given; i++)
162 daemon_set_log_color_or_die(conf.log_color_arg[i]);
163 }
164
165 /*
166 * setup shared memory area and get mutex for locking
167 */
168 static void init_ipc_or_die(void)
169 {
170 void *shm;
171 int shmid, ret = shm_new(sizeof(struct misc_meta_data));
172
173 if (ret < 0)
174 goto err_out;
175 shmid = ret;
176 ret = shm_attach(shmid, ATTACH_RW, &shm);
177 shm_destroy(shmid);
178 if (ret < 0)
179 goto err_out;
180 mmd = shm;
181
182 ret = mutex_new();
183 if (ret < 0)
184 goto err_out;
185 mmd_mutex = ret;
186
187 mmd->num_played = 0;
188 mmd->num_commands = 0;
189 mmd->events = 0;
190 mmd->num_connects = 0;
191 mmd->active_connections = 0;
192 mmd->vss_status_flags = VSS_NEXT;
193 mmd->new_vss_status_flags = VSS_NEXT;
194 return;
195 err_out:
196 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
197 exit(EXIT_FAILURE);
198 }
199
200 /**
201 * (Re-)read the server configuration files.
202 *
203 * \param override Passed to gengetopt to activate the override feature.
204 *
205 * This function also re-opens the logfile and sets the global \a
206 * user_list_file variable.
207 */
208 void parse_config_or_die(int override)
209 {
210 char *home = para_homedir();
211 int ret;
212 char *cf;
213
214 daemon_close_log();
215 if (conf.config_file_given)
216 cf = para_strdup(conf.config_file_arg);
217 else
218 cf = make_message("%s/.paraslash/server.conf", home);
219 free(user_list_file);
220 if (!conf.user_list_given)
221 user_list_file = make_message("%s/.paraslash/server.users", home);
222 else
223 user_list_file = para_strdup(conf.user_list_arg);
224 ret = file_exists(cf);
225 if (conf.config_file_given && !ret) {
226 ret = -1;
227 PARA_EMERG_LOG("can not read config file %s\n", cf);
228 goto out;
229 }
230 if (ret) {
231 int tmp = conf.daemon_given;
232 struct server_cmdline_parser_params params = {
233 .override = override,
234 .initialize = 0,
235 .check_required = 1,
236 .check_ambiguity = 0,
237 .print_errors = !conf.daemon_given
238 };
239 server_cmdline_parser_config_file(cf, &conf, &params);
240 daemon_set_loglevel(conf.loglevel_arg);
241 conf.daemon_given = tmp;
242 }
243 if (conf.logfile_given) {
244 daemon_set_logfile(conf.logfile_arg);
245 daemon_open_log_or_die();
246 }
247 init_colors_or_die();
248 daemon_set_flag(DF_LOG_PID);
249 daemon_set_flag(DF_LOG_LL);
250 daemon_set_flag(DF_LOG_TIME);
251 if (conf.log_timing_given)
252 daemon_set_flag(DF_LOG_TIMING);
253 ret = 1;
254 out:
255 free(cf);
256 free(home);
257 if (ret > 0)
258 return;
259 free(user_list_file);
260 user_list_file = NULL;
261 exit(EXIT_FAILURE);
262 }
263
264 static void signal_pre_select(struct sched *s, struct task *t)
265 {
266 struct signal_task *st = container_of(t, struct signal_task, task);
267 para_fd_set(st->fd, &s->rfds, &s->max_fileno);
268 }
269
270 /*
271 * called when server gets SIGHUP or when client invokes hup command.
272 */
273 static void handle_sighup(void)
274 {
275 PARA_NOTICE_LOG("SIGHUP\n");
276 parse_config_or_die(1); /* reopens log */
277 init_user_list(user_list_file); /* reload user list */
278 if (mmd->afs_pid)
279 kill(mmd->afs_pid, SIGHUP);
280 }
281
282 static int signal_post_select(struct sched *s, __a_unused struct task *t)
283 {
284 int signum = para_next_signal(&s->rfds);
285
286 switch (signum) {
287 case 0:
288 return 0;
289 case SIGHUP:
290 handle_sighup();
291 break;
292 case SIGCHLD:
293 for (;;) {
294 pid_t pid;
295 int ret = para_reap_child(&pid);
296 if (ret <= 0)
297 break;
298 if (pid != mmd->afs_pid)
299 continue;
300 PARA_EMERG_LOG("fatal: afs died\n");
301 kill(0, SIGTERM);
302 goto cleanup;
303 }
304 break;
305 /* die on sigint/sigterm. Kill all children too. */
306 case SIGINT:
307 case SIGTERM:
308 PARA_EMERG_LOG("terminating on signal %d\n", signum);
309 kill(0, SIGTERM);
310 /*
311 * We must wait for afs because afs catches SIGINT/SIGTERM.
312 * Before reacting to the signal, afs 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.
317 *
318 * There's no such problem with the other children of the
319 * server process (the command handlers) as these reset their
320 * SIGINT/SIGTERM handlers to the default action, i.e. these
321 * processes get killed immediately by the above kill().
322 */
323 PARA_INFO_LOG("waiting for afs (pid %d) to die\n",
324 (int)mmd->afs_pid);
325 waitpid(mmd->afs_pid, NULL, 0);
326 cleanup:
327 free(mmd->afd.afhi.chunk_table);
328 close_listed_fds();
329 mutex_destroy(mmd_mutex);
330 shm_detach(mmd);
331 exit(EXIT_FAILURE);
332 }
333 return 0;
334 }
335
336 static void init_signal_task(void)
337 {
338 static struct signal_task signal_task_struct,
339 *st = &signal_task_struct;
340
341 st->task.pre_select = signal_pre_select;
342 st->task.post_select = signal_post_select;
343 sprintf(st->task.status, "signal task");
344
345 PARA_NOTICE_LOG("setting up signal handling\n");
346 st->fd = para_signal_init(); /* always successful */
347 para_install_sighandler(SIGINT);
348 para_install_sighandler(SIGTERM);
349 para_install_sighandler(SIGHUP);
350 para_install_sighandler(SIGCHLD);
351 para_sigaction(SIGPIPE, SIG_IGN);
352 add_close_on_fork_list(st->fd);
353 register_task(&sched, &st->task);
354 }
355
356 static void command_pre_select(struct sched *s, struct task *t)
357 {
358 struct server_command_task *sct = container_of(t, struct server_command_task, task);
359 para_fd_set(sct->listen_fd, &s->rfds, &s->max_fileno);
360 }
361
362 static int command_post_select(struct sched *s, struct task *t)
363 {
364 struct server_command_task *sct = container_of(t, struct server_command_task, task);
365
366 int new_fd, ret, i;
367 char *peer_name;
368 pid_t child_pid;
369 uint32_t *chunk_table;
370
371 ret = para_accept(sct->listen_fd, &s->rfds, NULL, 0, &new_fd);
372 if (ret <= 0)
373 goto out;
374 peer_name = remote_name(new_fd);
375 PARA_INFO_LOG("got connection from %s, forking\n", peer_name);
376 mmd->num_connects++;
377 mmd->active_connections++;
378 /*
379 * The chunk table is a pointer located in the mmd struct that points
380 * to dynamically allocated memory, i.e. it must be freed by the parent
381 * and the child. However, as the mmd struct is in a shared memory
382 * area, there's no guarantee that after the fork this pointer is still
383 * valid in child context. As it is not used in the child anyway, we
384 * save it to a local variable before the fork and free the memory via
385 * that copy in the child directly after the fork.
386 */
387 chunk_table = mmd->afd.afhi.chunk_table;
388 child_pid = fork();
389 if (child_pid < 0) {
390 ret = -ERRNO_TO_PARA_ERROR(errno);
391 goto out;
392 }
393 if (child_pid) {
394 close(new_fd);
395 /* parent keeps accepting connections */
396 return 0;
397 }
398 /* mmd might already have changed at this point */
399 free(chunk_table);
400 alarm(ALARM_TIMEOUT);
401 close_listed_fds();
402 para_signal_shutdown();
403 /*
404 * put info on who we are serving into argv[0] to make
405 * client ip visible in top/ps
406 */
407 for (i = sct->argc - 1; i >= 0; i--)
408 memset(sct->argv[i], 0, strlen(sct->argv[i]));
409 sprintf(sct->argv[0], "para_server (serving %s)", peer_name);
410 handle_connect(new_fd, peer_name);
411 /* never reached*/
412 out:
413 if (ret < 0)
414 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
415 return 0;
416 }
417
418 static void init_server_command_task(int argc, char **argv)
419 {
420 int ret;
421 static struct server_command_task server_command_task_struct,
422 *sct = &server_command_task_struct;
423
424 PARA_NOTICE_LOG("initializing tcp command socket\n");
425 sct->task.pre_select = command_pre_select;
426 sct->task.post_select = command_post_select;
427 sct->argc = argc;
428 sct->argv = argv;
429 ret = para_listen_simple(IPPROTO_TCP, conf.port_arg);
430 if (ret < 0)
431 goto err;
432 sct->listen_fd = ret;
433 ret = mark_fd_nonblocking(sct->listen_fd);
434 if (ret < 0)
435 goto err;
436 add_close_on_fork_list(sct->listen_fd); /* child doesn't need the listener */
437 sprintf(sct->task.status, "server command task");
438 register_task(&sched, &sct->task);
439 return;
440 err:
441 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
442 exit(EXIT_FAILURE);
443 }
444
445 static int init_afs(int argc, char **argv)
446 {
447 int ret, afs_server_socket[2];
448 pid_t afs_pid;
449
450 ret = socketpair(PF_UNIX, SOCK_DGRAM, 0, afs_server_socket);
451 if (ret < 0)
452 exit(EXIT_FAILURE);
453 get_random_bytes_or_die((unsigned char *)&afs_socket_cookie,
454 sizeof(afs_socket_cookie));
455 afs_pid = fork();
456 if (afs_pid < 0)
457 exit(EXIT_FAILURE);
458 if (afs_pid == 0) { /* child (afs) */
459 int i;
460 for (i = argc - 1; i >= 0; i--)
461 memset(argv[i], 0, strlen(argv[i]));
462 sprintf(argv[0], "para_server (afs)");
463 close(afs_server_socket[0]);
464 afs_init(afs_socket_cookie, afs_server_socket[1]);
465 }
466 mmd->afs_pid = afs_pid;
467 close(afs_server_socket[1]);
468 ret = mark_fd_nonblocking(afs_server_socket[0]);
469 if (ret < 0)
470 exit(EXIT_FAILURE);
471 add_close_on_fork_list(afs_server_socket[0]);
472 PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
473 afs_server_socket[0], (unsigned) afs_socket_cookie);
474 return afs_server_socket[0];
475 }
476
477 __noreturn static void print_help_and_die(void)
478 {
479 struct ggo_help h = DEFINE_GGO_HELP(server);
480 bool d = conf.detailed_help_given;
481
482 ggo_print_help(&h, d? GPH_STANDARD_FLAGS_DETAILED : GPH_STANDARD_FLAGS);
483 exit(0);
484 }
485
486 static void server_init(int argc, char **argv)
487 {
488 struct server_cmdline_parser_params params = {
489 .override = 0,
490 .initialize = 1,
491 .check_required = 0,
492 .check_ambiguity = 0,
493 .print_errors = 1
494 };
495 int afs_socket;
496
497 valid_fd_012();
498 init_random_seed_or_die();
499 /* parse command line options */
500 server_cmdline_parser_ext(argc, argv, &conf, &params);
501 daemon_set_loglevel(conf.loglevel_arg);
502 version_handle_flag("server", conf.version_given);
503 if (conf.help_given || conf.detailed_help_given)
504 print_help_and_die();
505 drop_privileges_or_die(conf.user_arg, conf.group_arg);
506 /* parse config file, open log and set defaults */
507 parse_config_or_die(0);
508 log_welcome("para_server");
509 init_ipc_or_die(); /* init mmd struct and mmd->lock */
510 /* make sure, the global now pointer is uptodate */
511 clock_get_realtime(now);
512 set_server_start_time(now);
513 init_user_list(user_list_file);
514 /* become daemon */
515 if (conf.daemon_given)
516 daemonize(true /* parent waits for SIGTERM */);
517 PARA_NOTICE_LOG("initializing audio format handlers\n");
518 afh_init();
519
520 /*
521 * Although afs uses its own signal handling we must ignore SIGUSR1
522 * _before_ the afs child process gets born by init_afs() below. It's
523 * racy to do this in the child because the parent might send SIGUSR1
524 * before the child gets a chance to ignore this signal -- only the
525 * good die young.
526 */
527 para_sigaction(SIGUSR1, SIG_IGN);
528 /*
529 * We have to block SIGCHLD before the afs process is being forked off.
530 * Otherwise, para_server does not notice if afs dies before the
531 * SIGCHLD handler has been installed for the parent process by
532 * init_signal_task() below.
533 */
534 para_block_signal(SIGCHLD);
535 PARA_NOTICE_LOG("initializing the audio file selector\n");
536 afs_socket = init_afs(argc, argv);
537 init_signal_task();
538 para_unblock_signal(SIGCHLD);
539 PARA_NOTICE_LOG("initializing virtual streaming system\n");
540 init_vss_task(afs_socket, &sched);
541 init_server_command_task(argc, argv);
542 if (conf.daemon_given)
543 kill(getppid(), SIGTERM);
544 PARA_NOTICE_LOG("server init complete\n");
545 }
546
547 static void status_refresh(void)
548 {
549 static int prev_uptime = -1, prev_events = -1;
550 int uptime = get_server_uptime(now);
551
552 if (prev_events != mmd->events)
553 goto out;
554 if (mmd->new_vss_status_flags != mmd->vss_status_flags)
555 goto out_inc_events;
556 if (uptime / 60 != prev_uptime / 60)
557 goto out_inc_events;
558 return;
559 out_inc_events:
560 mmd->events++;
561 out:
562 prev_uptime = uptime;
563 prev_events = mmd->events;
564 mmd->vss_status_flags = mmd->new_vss_status_flags;
565 PARA_DEBUG_LOG("%d events, forcing status update\n", mmd->events);
566 killpg(0, SIGUSR1);
567 }
568
569 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
570 struct timeval *timeout_tv)
571 {
572 int ret;
573
574 status_refresh();
575 mutex_unlock(mmd_mutex);
576 ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
577 mutex_lock(mmd_mutex);
578 return ret;
579 }
580
581 /**
582 * The main function of para_server.
583 *
584 * \param argc Usual argument count.
585 * \param argv Usual argument vector.
586 *
587 * \return EXIT_SUCCESS or EXIT_FAILURE.
588 */
589 int main(int argc, char *argv[])
590 {
591 int ret;
592
593 sched.default_timeout.tv_sec = 1;
594 sched.select_function = server_select;
595
596 server_init(argc, argv);
597 mutex_lock(mmd_mutex);
598 ret = schedule(&sched);
599 if (ret < 0) {
600 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
601 exit(EXIT_FAILURE);
602 }
603 exit(EXIT_SUCCESS);
604 }