f3d5237f19cfbc69e01ca17851f698fda1b41779
[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 "version.h"
95
96 __printf_2_3 void (*para_log)(int, const char*, ...) = daemon_log;
97
98 /** Define the array of error lists needed by para_server. */
99 INIT_SERVER_ERRLISTS;
100
101 /** Shut down non-authorized connections after that many seconds. */
102 #define ALARM_TIMEOUT 10
103
104 /**
105 * Pointer to shared memory area for communication between para_server
106 * and its children. Exported to vss.c. command.c and to afs.
107 */
108 struct misc_meta_data *mmd;
109
110 /**
111 * The configuration of para_server
112 *
113 * It also contains the options for the audio file selector, audio format
114 * handler and all supported senders.
115 */
116 struct server_args_info conf;
117
118 /** A random value used in child context for authentication. */
119 uint32_t afs_socket_cookie;
120
121 /** The mutex protecting the shared memory area containing the mmd struct. */
122 int mmd_mutex;
123
124 /** The file containing user information (public key, permissions). */
125 static char *user_list_file = NULL;
126
127 static struct sched sched;
128
129 /** The task responsible for server command handling. */
130 struct server_command_task {
131 /** TCP port on which para_server listens for connections. */
132 int listen_fd;
133 /** Copied from para_server's main function. */
134 int argc;
135 /** Argument vector passed to para_server's main function. */
136 char **argv;
137 /** The command task structure for scheduling. */
138 struct task task;
139 };
140
141 static int want_colors(void)
142 {
143 if (conf.color_arg == color_arg_no)
144 return 0;
145 if (conf.color_arg == color_arg_yes)
146 return 1;
147 if (conf.logfile_given)
148 return 0;
149 return isatty(STDERR_FILENO);
150 }
151
152 static void init_colors_or_die(void)
153 {
154 int i;
155
156 if (!want_colors())
157 return;
158 daemon_set_flag(DF_COLOR_LOG);
159 daemon_set_default_log_colors();
160 for (i = 0; i < conf.log_color_given; i++)
161 daemon_set_log_color_or_die(conf.log_color_arg[i]);
162 }
163
164 /*
165 * setup shared memory area and get mutex for locking
166 */
167 static void init_ipc_or_die(void)
168 {
169 void *shm;
170 int shmid, ret = shm_new(sizeof(struct misc_meta_data));
171
172 if (ret < 0)
173 goto err_out;
174 shmid = ret;
175 ret = shm_attach(shmid, ATTACH_RW, &shm);
176 shm_destroy(shmid);
177 if (ret < 0)
178 goto err_out;
179 mmd = shm;
180
181 ret = mutex_new();
182 if (ret < 0)
183 goto err_out;
184 mmd_mutex = ret;
185
186 mmd->num_played = 0;
187 mmd->num_commands = 0;
188 mmd->events = 0;
189 mmd->num_connects = 0;
190 mmd->active_connections = 0;
191 mmd->vss_status_flags = VSS_NEXT;
192 mmd->new_vss_status_flags = VSS_NEXT;
193 return;
194 err_out:
195 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
196 exit(EXIT_FAILURE);
197 }
198
199 /**
200 * (Re-)read the server configuration files.
201 *
202 * \param override Passed to gengetopt to activate the override feature.
203 *
204 * This function also re-opens the logfile and sets the global \a
205 * user_list_file variable.
206 */
207 void parse_config_or_die(int override)
208 {
209 char *home = para_homedir();
210 int ret;
211 char *cf;
212
213 daemon_close_log();
214 if (conf.config_file_given)
215 cf = para_strdup(conf.config_file_arg);
216 else
217 cf = make_message("%s/.paraslash/server.conf", home);
218 free(user_list_file);
219 if (!conf.user_list_given)
220 user_list_file = make_message("%s/.paraslash/server.users", home);
221 else
222 user_list_file = para_strdup(conf.user_list_arg);
223 ret = file_exists(cf);
224 if (conf.config_file_given && !ret) {
225 ret = -1;
226 PARA_EMERG_LOG("can not read config file %s\n", cf);
227 goto out;
228 }
229 if (ret) {
230 int tmp = conf.daemon_given;
231 struct server_cmdline_parser_params params = {
232 .override = override,
233 .initialize = 0,
234 .check_required = 1,
235 .check_ambiguity = 0,
236 .print_errors = !conf.daemon_given
237 };
238 server_cmdline_parser_config_file(cf, &conf, &params);
239 conf.daemon_given = tmp;
240 }
241 if (conf.logfile_given) {
242 daemon_set_logfile(conf.logfile_arg);
243 daemon_open_log_or_die();
244 }
245 daemon_set_loglevel(conf.loglevel_arg);
246 init_colors_or_die();
247 daemon_set_flag(DF_LOG_PID);
248 daemon_set_flag(DF_LOG_LL);
249 daemon_set_flag(DF_LOG_TIME);
250 if (conf.log_timing_given)
251 daemon_set_flag(DF_LOG_TIMING);
252 ret = 1;
253 out:
254 free(cf);
255 free(home);
256 if (ret > 0)
257 return;
258 free(user_list_file);
259 user_list_file = NULL;
260 exit(EXIT_FAILURE);
261 }
262
263 static void signal_pre_select(struct sched *s, struct task *t)
264 {
265 struct signal_task *st = container_of(t, struct signal_task, task);
266 para_fd_set(st->fd, &s->rfds, &s->max_fileno);
267 }
268
269 /*
270 * called when server gets SIGHUP or when client invokes hup command.
271 */
272 static void handle_sighup(void)
273 {
274 PARA_NOTICE_LOG("SIGHUP\n");
275 parse_config_or_die(1); /* reopens log */
276 init_user_list(user_list_file); /* reload user list */
277 if (mmd->afs_pid)
278 kill(mmd->afs_pid, SIGHUP);
279 }
280
281 static int signal_post_select(struct sched *s, __a_unused struct task *t)
282 {
283 int signum = para_next_signal(&s->rfds);
284
285 switch (signum) {
286 case 0:
287 return 0;
288 case SIGHUP:
289 handle_sighup();
290 break;
291 case SIGCHLD:
292 for (;;) {
293 pid_t pid;
294 int ret = para_reap_child(&pid);
295 if (ret <= 0)
296 break;
297 if (pid != mmd->afs_pid)
298 continue;
299 PARA_EMERG_LOG("fatal: afs died\n");
300 kill(0, SIGTERM);
301 goto cleanup;
302 }
303 break;
304 /* die on sigint/sigterm. Kill all children too. */
305 case SIGINT:
306 case SIGTERM:
307 PARA_EMERG_LOG("terminating on signal %d\n", signum);
308 kill(0, SIGTERM);
309 /*
310 * We must wait for afs because afs catches SIGINT/SIGTERM.
311 * Before reacting to the signal, afs might want to use the
312 * shared memory area and the mmd mutex. If we destroy this
313 * mutex too early and afs tries to lock the shared memory
314 * area, the call to mutex_lock() will fail and terminate the
315 * afs process. This leads to dirty osl tables.
316 *
317 * There's no such problem with the other children of the
318 * server process (the command handlers) as these reset their
319 * SIGINT/SIGTERM handlers to the default action, i.e. these
320 * processes get killed immediately by the above kill().
321 */
322 PARA_INFO_LOG("waiting for afs (pid %d) to die\n",
323 (int)mmd->afs_pid);
324 waitpid(mmd->afs_pid, NULL, 0);
325 cleanup:
326 free(mmd->afd.afhi.chunk_table);
327 close_listed_fds();
328 mutex_destroy(mmd_mutex);
329 shm_detach(mmd);
330 exit(EXIT_FAILURE);
331 }
332 return 0;
333 }
334
335 static void init_signal_task(void)
336 {
337 static struct signal_task signal_task_struct,
338 *st = &signal_task_struct;
339
340 st->task.pre_select = signal_pre_select;
341 st->task.post_select = signal_post_select;
342 sprintf(st->task.status, "signal task");
343
344 PARA_NOTICE_LOG("setting up signal handling\n");
345 st->fd = para_signal_init(); /* always successful */
346 para_install_sighandler(SIGINT);
347 para_install_sighandler(SIGTERM);
348 para_install_sighandler(SIGHUP);
349 para_install_sighandler(SIGCHLD);
350 para_sigaction(SIGPIPE, SIG_IGN);
351 add_close_on_fork_list(st->fd);
352 register_task(&sched, &st->task);
353 }
354
355 static void command_pre_select(struct sched *s, struct task *t)
356 {
357 struct server_command_task *sct = container_of(t, struct server_command_task, task);
358 para_fd_set(sct->listen_fd, &s->rfds, &s->max_fileno);
359 }
360
361 static int command_post_select(struct sched *s, struct task *t)
362 {
363 struct server_command_task *sct = container_of(t, struct server_command_task, task);
364
365 int new_fd, ret, i;
366 char *peer_name;
367 pid_t child_pid;
368 uint32_t *chunk_table;
369
370 ret = para_accept(sct->listen_fd, &s->rfds, NULL, 0, &new_fd);
371 if (ret <= 0)
372 goto out;
373 peer_name = remote_name(new_fd);
374 PARA_INFO_LOG("got connection from %s, forking\n", peer_name);
375 mmd->num_connects++;
376 mmd->active_connections++;
377 /*
378 * The chunk table is a pointer located in the mmd struct that points
379 * to dynamically allocated memory, i.e. it must be freed by the parent
380 * and the child. However, as the mmd struct is in a shared memory
381 * area, there's no guarantee that after the fork this pointer is still
382 * valid in child context. As it is not used in the child anyway, we
383 * save it to a local variable before the fork and free the memory via
384 * that copy in the child directly after the fork.
385 */
386 chunk_table = mmd->afd.afhi.chunk_table;
387 child_pid = fork();
388 if (child_pid < 0) {
389 ret = -ERRNO_TO_PARA_ERROR(errno);
390 goto out;
391 }
392 if (child_pid) {
393 close(new_fd);
394 /* parent keeps accepting connections */
395 return 0;
396 }
397 /* mmd might already have changed at this point */
398 free(chunk_table);
399 alarm(ALARM_TIMEOUT);
400 close_listed_fds();
401 para_signal_shutdown();
402 /*
403 * put info on who we are serving into argv[0] to make
404 * client ip visible in top/ps
405 */
406 for (i = sct->argc - 1; i >= 0; i--)
407 memset(sct->argv[i], 0, strlen(sct->argv[i]));
408 sprintf(sct->argv[0], "para_server (serving %s)", peer_name);
409 handle_connect(new_fd, peer_name);
410 /* never reached*/
411 out:
412 if (ret < 0)
413 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
414 return 0;
415 }
416
417 static void init_server_command_task(int argc, char **argv)
418 {
419 int ret;
420 static struct server_command_task server_command_task_struct,
421 *sct = &server_command_task_struct;
422
423 PARA_NOTICE_LOG("initializing tcp command socket\n");
424 sct->task.pre_select = command_pre_select;
425 sct->task.post_select = command_post_select;
426 sct->argc = argc;
427 sct->argv = argv;
428 ret = para_listen_simple(IPPROTO_TCP, conf.port_arg);
429 if (ret < 0)
430 goto err;
431 sct->listen_fd = ret;
432 ret = mark_fd_nonblocking(sct->listen_fd);
433 if (ret < 0)
434 goto err;
435 add_close_on_fork_list(sct->listen_fd); /* child doesn't need the listener */
436 sprintf(sct->task.status, "server command task");
437 register_task(&sched, &sct->task);
438 return;
439 err:
440 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
441 exit(EXIT_FAILURE);
442 }
443
444 static int init_afs(int argc, char **argv)
445 {
446 int ret, afs_server_socket[2];
447 pid_t afs_pid;
448
449 ret = socketpair(PF_UNIX, SOCK_DGRAM, 0, afs_server_socket);
450 if (ret < 0)
451 exit(EXIT_FAILURE);
452 get_random_bytes_or_die((unsigned char *)&afs_socket_cookie,
453 sizeof(afs_socket_cookie));
454 afs_pid = fork();
455 if (afs_pid < 0)
456 exit(EXIT_FAILURE);
457 if (afs_pid == 0) { /* child (afs) */
458 int i;
459 for (i = argc - 1; i >= 0; i--)
460 memset(argv[i], 0, strlen(argv[i]));
461 sprintf(argv[0], "para_server (afs)");
462 close(afs_server_socket[0]);
463 afs_init(afs_socket_cookie, afs_server_socket[1]);
464 }
465 mmd->afs_pid = afs_pid;
466 close(afs_server_socket[1]);
467 ret = mark_fd_nonblocking(afs_server_socket[0]);
468 if (ret < 0)
469 exit(EXIT_FAILURE);
470 add_close_on_fork_list(afs_server_socket[0]);
471 PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
472 afs_server_socket[0], (unsigned) afs_socket_cookie);
473 return afs_server_socket[0];
474 }
475
476 static void server_init(int argc, char **argv)
477 {
478 struct server_cmdline_parser_params params = {
479 .override = 0,
480 .initialize = 1,
481 .check_required = 0,
482 .check_ambiguity = 0,
483 .print_errors = 1
484 };
485 int afs_socket;
486
487 valid_fd_012();
488 init_random_seed_or_die();
489 /* parse command line options */
490 server_cmdline_parser_ext(argc, argv, &conf, &params);
491 HANDLE_VERSION_FLAG("server", conf);
492 drop_privileges_or_die(conf.user_arg, conf.group_arg);
493 /* parse config file, open log and set defaults */
494 parse_config_or_die(0);
495 log_welcome("para_server");
496 init_ipc_or_die(); /* init mmd struct and mmd->lock */
497 /* make sure, the global now pointer is uptodate */
498 clock_get_realtime(now);
499 set_server_start_time(now);
500 init_user_list(user_list_file);
501 /* become daemon */
502 if (conf.daemon_given)
503 daemonize(true /* parent waits for SIGTERM */);
504 PARA_NOTICE_LOG("initializing audio format handlers\n");
505 afh_init();
506
507 /*
508 * Although afs uses its own signal handling we must ignore SIGUSR1
509 * _before_ the afs child process gets born by init_afs() below. It's
510 * racy to do this in the child because the parent might send SIGUSR1
511 * before the child gets a chance to ignore this signal -- only the
512 * good die young.
513 */
514 para_sigaction(SIGUSR1, SIG_IGN);
515 /*
516 * We have to block SIGCHLD before the afs process is being forked off.
517 * Otherwise, para_server does not notice if afs dies before the
518 * SIGCHLD handler has been installed for the parent process by
519 * init_signal_task() below.
520 */
521 para_block_signal(SIGCHLD);
522 PARA_NOTICE_LOG("initializing the audio file selector\n");
523 afs_socket = init_afs(argc, argv);
524 init_signal_task();
525 para_unblock_signal(SIGCHLD);
526 PARA_NOTICE_LOG("initializing virtual streaming system\n");
527 init_vss_task(afs_socket, &sched);
528 init_server_command_task(argc, argv);
529 if (conf.daemon_given)
530 kill(getppid(), SIGTERM);
531 PARA_NOTICE_LOG("server init complete\n");
532 }
533
534 static void status_refresh(void)
535 {
536 static int prev_uptime = -1, prev_events = -1;
537 int uptime = get_server_uptime(now);
538
539 if (prev_events != mmd->events)
540 goto out;
541 if (mmd->new_vss_status_flags != mmd->vss_status_flags)
542 goto out_inc_events;
543 if (uptime / 60 != prev_uptime / 60)
544 goto out_inc_events;
545 return;
546 out_inc_events:
547 mmd->events++;
548 out:
549 prev_uptime = uptime;
550 prev_events = mmd->events;
551 mmd->vss_status_flags = mmd->new_vss_status_flags;
552 PARA_DEBUG_LOG("%d events, forcing status update\n", mmd->events);
553 killpg(0, SIGUSR1);
554 }
555
556 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
557 struct timeval *timeout_tv)
558 {
559 int ret;
560
561 status_refresh();
562 mutex_unlock(mmd_mutex);
563 ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
564 mutex_lock(mmd_mutex);
565 return ret;
566 }
567
568 /**
569 * The main function of para_server.
570 *
571 * \param argc Usual argument count.
572 * \param argv Usual argument vector.
573 *
574 * \return EXIT_SUCCESS or EXIT_FAILURE.
575 */
576 int main(int argc, char *argv[])
577 {
578 int ret;
579
580 sched.default_timeout.tv_sec = 1;
581 sched.select_function = server_select;
582
583 server_init(argc, argv);
584 mutex_lock(mmd_mutex);
585 ret = schedule(&sched);
586 if (ret < 0) {
587 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
588 exit(EXIT_FAILURE);
589 }
590 exit(EXIT_SUCCESS);
591 }