6b1e11d6fb580b1edd8da144e3c47b2977fb1d2e
[paraslash.git] / server.c
1 /*
2 * Copyright (C) 1997-2011 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
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, \ref filter_node.
21 *
22 *
23 * The gory details, listed by topic:
24 *
25 * - Audio format handlers: \ref send_common.c \ref mp3_afh.c,
26 * \ref ogg_afh.c, \ref aac_afh.c, \ref wma_afh.c, \ref spx_afh.c
27 * - Decoders: \ref mp3dec_filter.c, \ref oggdec_filter.c,
28 * \ref aacdec_filter.c, \ref wmadec_filter.c, spxdec_filter.c,
29 * - Volume normalizer: \ref compress_filter.c,
30 * - Output: \ref alsa_write.c, \ref osx_write.c, \ref oss_write.c,
31 * - http: \ref http_recv.c, \ref http_send.c,
32 * - udp: \ref udp_recv.c, \ref udp_send.c,
33 * - dccp: \ref dccp_recv.c, \ref dccp_send.c,
34 * - Audio file selector: \ref afs.c, \ref aft.c, \ref mood.c,
35 * - Afs structures: \ref afs_table, \ref audio_file_data,
36 * \ref afs_info \ref afh_info,
37 * - Afs tables: \ref aft.c, \ref mood.c, \ref playlist.c,
38 * \ref attribute.c, \ref score.c,
39 * - The virtual streaming system: \ref vss.c, \ref chunk_queue.c.
40 *
41 * Lower levels:
42 *
43 * - Scheduling: \ref sched.c, \ref sched.h,
44 * - Networking: \ref net.c,
45 * - File descriptors: \ref fd.c,
46 * - Signals: \ref signal.c,
47 * - Daemons: \ref daemon.c,
48 * - Strings: \ref string.c, \ref string.h,
49 * - Time: \ref time.c,
50 * - Spawning processes: \ref exec.c,
51 * - Inter process communication: \ref ipc.c,
52 * - Blob tables: \ref blob.c,
53 * - The error subssystem: \ref error.h.
54 * - Access control for paraslash senders: \ref acl.c, \ref acl.h.
55 * - Internal crypto API: \ref crypt.h.
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 <signal.h>
67 #include <sys/time.h>
68 #include <regex.h>
69 #include <osl.h>
70 #include <stdbool.h>
71
72 #include "para.h"
73 #include "error.h"
74 #include "crypt.h"
75 #include "server.cmdline.h"
76 #include "afh.h"
77 #include "string.h"
78 #include "afs.h"
79 #include "server.h"
80 #include "list.h"
81 #include "send.h"
82 #include "vss.h"
83 #include "config.h"
84 #include "close_on_fork.h"
85 #include "net.h"
86 #include "daemon.h"
87 #include "ipc.h"
88 #include "fd.h"
89 #include "sched.h"
90 #include "signal.h"
91 #include "user_list.h"
92 #include "color.h"
93 #include "version.h"
94
95 /** Define the array of error lists needed by para_server. */
96 INIT_SERVER_ERRLISTS;
97
98 /** Shut down non-authorized connections after that many seconds. */
99 #define ALARM_TIMEOUT 10
100
101 /**
102 * Pointer to shared memory area for communication between para_server
103 * and its children. Exported to vss.c. command.c and to afs.
104 */
105 struct misc_meta_data *mmd;
106
107 /**
108 * The configuration of para_server
109 *
110 * It also contains the options for the audio file selector, audio format
111 * handler and all supported senders.
112 */
113 struct server_args_info conf;
114
115 /** A random value used in child context for authentication. */
116 uint32_t afs_socket_cookie;
117
118 /** The mutex protecting the shared memory area containing the mmd struct. */
119 int mmd_mutex;
120
121 /** The file containing user information (public key, permissions). */
122 static char *user_list_file = NULL;
123
124
125 /** The task responsible for server command handling. */
126 struct server_command_task {
127 /** TCP port on which para_server listens for connections. */
128 int listen_fd;
129 /** Copied from para_server's main function. */
130 int argc;
131 /** Argument vector passed to para_server's main function. */
132 char **argv;
133 /** The command task structure for scheduling. */
134 struct task task;
135 };
136
137 static int want_colors(void)
138 {
139 if (conf.color_arg == color_arg_no)
140 return 0;
141 if (conf.color_arg == color_arg_yes)
142 return 1;
143 if (conf.logfile_given)
144 return 0;
145 return isatty(STDERR_FILENO);
146 }
147
148 static void init_colors_or_die(void)
149 {
150 int i;
151
152 if (!want_colors())
153 return;
154 daemon_set_flag(DF_COLOR_LOG);
155 daemon_set_default_log_colors();
156 for (i = 0; i < conf.log_color_given; i++)
157 daemon_set_log_color_or_die(conf.log_color_arg[i]);
158 }
159
160 /*
161 * setup shared memory area and get mutex for locking
162 */
163 static void init_ipc_or_die(void)
164 {
165 void *shm;
166 int shmid, ret = shm_new(sizeof(struct misc_meta_data));
167
168 if (ret < 0)
169 goto err_out;
170 shmid = ret;
171 ret = shm_attach(shmid, ATTACH_RW, &shm);
172 shm_destroy(shmid);
173 if (ret < 0)
174 goto err_out;
175 mmd = shm;
176
177 ret = mutex_new();
178 if (ret < 0)
179 goto err_out;
180 mmd_mutex = ret;
181
182 mmd->num_played = 0;
183 mmd->num_commands = 0;
184 mmd->events = 0;
185 mmd->num_connects = 0;
186 mmd->active_connections = 0;
187 mmd->vss_status_flags = VSS_NEXT;
188 mmd->new_vss_status_flags = VSS_NEXT;
189 return;
190 err_out:
191 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
192 exit(EXIT_FAILURE);
193 }
194
195 /**
196 * (Re-)read the server configuration files.
197 *
198 * \param override Passed to gengetopt to activate the override feature.
199 *
200 * This function also re-opens the logfile and sets the global \a
201 * user_list_file variable.
202 */
203 void parse_config_or_die(int override)
204 {
205 char *home = para_homedir();
206 int ret;
207 char *cf;
208
209 daemon_close_log();
210 if (conf.config_file_given)
211 cf = para_strdup(conf.config_file_arg);
212 else
213 cf = make_message("%s/.paraslash/server.conf", home);
214 free(user_list_file);
215 if (!conf.user_list_given)
216 user_list_file = make_message("%s/.paraslash/server.users", home);
217 else
218 user_list_file = para_strdup(conf.user_list_arg);
219 ret = file_exists(cf);
220 if (conf.config_file_given && !ret) {
221 ret = -1;
222 PARA_EMERG_LOG("can not read config file %s\n", cf);
223 goto out;
224 }
225 if (ret) {
226 int tmp = conf.daemon_given;
227 struct server_cmdline_parser_params params = {
228 .override = override,
229 .initialize = 0,
230 .check_required = 1,
231 .check_ambiguity = 0,
232 .print_errors = !conf.daemon_given
233 };
234 server_cmdline_parser_config_file(cf, &conf, &params);
235 conf.daemon_given = tmp;
236 }
237 if (conf.logfile_given) {
238 daemon_set_logfile(conf.logfile_arg);
239 daemon_open_log_or_die();
240 }
241 daemon_set_loglevel(conf.loglevel_arg);
242 init_colors_or_die();
243 daemon_set_flag(DF_LOG_PID);
244 daemon_set_flag(DF_LOG_LL);
245 daemon_set_flag(DF_LOG_TIME);
246 if (conf.log_timing_given)
247 daemon_set_flag(DF_LOG_TIMING);
248 ret = 1;
249 out:
250 free(cf);
251 free(home);
252 if (ret > 0)
253 return;
254 free(user_list_file);
255 user_list_file = NULL;
256 exit(EXIT_FAILURE);
257 }
258
259 static void signal_pre_select(struct sched *s, struct task *t)
260 {
261 struct signal_task *st = container_of(t, struct signal_task, task);
262 para_fd_set(st->fd, &s->rfds, &s->max_fileno);
263 }
264
265 /*
266 * called when server gets SIGHUP or when client invokes hup command.
267 */
268 static void handle_sighup(void)
269 {
270 PARA_NOTICE_LOG("SIGHUP\n");
271 parse_config_or_die(1); /* reopens log */
272 init_user_list(user_list_file); /* reload user list */
273 if (mmd->afs_pid)
274 kill(mmd->afs_pid, SIGHUP);
275 }
276
277 static void signal_post_select(struct sched *s, __a_unused struct task *t)
278 {
279 int signum = para_next_signal(&s->rfds);
280
281 switch (signum) {
282 case 0:
283 return;
284 case SIGHUP:
285 handle_sighup();
286 break;
287 case SIGCHLD:
288 for (;;) {
289 pid_t pid;
290 int ret = para_reap_child(&pid);
291 if (ret <= 0)
292 break;
293 if (pid != mmd->afs_pid)
294 continue;
295 PARA_EMERG_LOG("fatal: afs died\n");
296 kill(0, SIGTERM);
297 goto cleanup;
298 }
299 break;
300 /* die on sigint/sigterm. Kill all children too. */
301 case SIGINT:
302 case SIGTERM:
303 PARA_EMERG_LOG("terminating on signal %d\n", signum);
304 kill(0, SIGTERM);
305 /*
306 * We must wait for afs because afs catches SIGINT/SIGTERM.
307 * Before reacting to the signal, afs might want to use the
308 * shared memory area and the mmd mutex. If we destroy this
309 * mutex too early and afs tries to lock the shared memory
310 * area, the call to mutex_lock() will fail and terminate the
311 * afs process. This leads to dirty osl tables.
312 *
313 * There's no such problem with the other children of the
314 * server process (the command handlers) as these reset their
315 * SIGINT/SIGTERM handlers to the default action, i.e. these
316 * processes get killed immediately by the above kill().
317 */
318 PARA_INFO_LOG("waiting for afs (pid %d) to die\n",
319 (int)mmd->afs_pid);
320 waitpid(mmd->afs_pid, NULL, 0);
321 cleanup:
322 free(mmd->afd.afhi.chunk_table);
323 close_listed_fds();
324 mutex_destroy(mmd_mutex);
325 shm_detach(mmd);
326 exit(EXIT_FAILURE);
327 }
328 }
329
330 static void init_signal_task(void)
331 {
332 static struct signal_task signal_task_struct,
333 *st = &signal_task_struct;
334
335 st->task.pre_select = signal_pre_select;
336 st->task.post_select = signal_post_select;
337 sprintf(st->task.status, "signal task");
338
339 PARA_NOTICE_LOG("setting up signal handling\n");
340 st->fd = para_signal_init(); /* always successful */
341 para_install_sighandler(SIGINT);
342 para_install_sighandler(SIGTERM);
343 para_install_sighandler(SIGHUP);
344 para_install_sighandler(SIGCHLD);
345 para_sigaction(SIGPIPE, SIG_IGN);
346 add_close_on_fork_list(st->fd);
347 register_task(&st->task);
348 }
349
350 static void command_pre_select(struct sched *s, struct task *t)
351 {
352 struct server_command_task *sct = container_of(t, struct server_command_task, task);
353 para_fd_set(sct->listen_fd, &s->rfds, &s->max_fileno);
354 }
355
356 static void command_post_select(struct sched *s, struct task *t)
357 {
358 struct server_command_task *sct = container_of(t, struct server_command_task, task);
359
360 int new_fd, ret, i;
361 char *peer_name;
362 pid_t child_pid;
363 uint32_t *chunk_table;
364
365 ret = para_accept(sct->listen_fd, &s->rfds, NULL, 0, &new_fd);
366 if (ret <= 0)
367 goto out;
368 peer_name = remote_name(new_fd);
369 PARA_INFO_LOG("got connection from %s, forking\n", peer_name);
370 mmd->num_connects++;
371 mmd->active_connections++;
372 /*
373 * The chunk table is a pointer located in the mmd struct that points
374 * to dynamically allocated memory, i.e. it must be freed by the parent
375 * and the child. However, as the mmd struct is in a shared memory
376 * area, there's no guarantee that after the fork this pointer is still
377 * valid in child context. As it is not used in the child anyway, we
378 * save it to a local variable before the fork and free the memory via
379 * that copy in the child directly after the fork.
380 */
381 chunk_table = mmd->afd.afhi.chunk_table;
382 child_pid = fork();
383 if (child_pid < 0) {
384 ret = -ERRNO_TO_PARA_ERROR(errno);
385 goto out;
386 }
387 if (child_pid) {
388 close(new_fd);
389 /* parent keeps accepting connections */
390 return;
391 }
392 /* mmd might already have changed at this point */
393 free(chunk_table);
394 alarm(ALARM_TIMEOUT);
395 close_listed_fds();
396 para_signal_shutdown();
397 /*
398 * put info on who we are serving into argv[0] to make
399 * client ip visible in top/ps
400 */
401 for (i = sct->argc - 1; i >= 0; i--)
402 memset(sct->argv[i], 0, strlen(sct->argv[i]));
403 sprintf(sct->argv[0], "para_server (serving %s)", peer_name);
404 return handle_connect(new_fd, peer_name);
405 out:
406 if (ret < 0)
407 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
408 }
409
410 static void init_server_command_task(int argc, char **argv)
411 {
412 int ret;
413 static struct server_command_task server_command_task_struct,
414 *sct = &server_command_task_struct;
415
416 PARA_NOTICE_LOG("initializing tcp command socket\n");
417 sct->task.pre_select = command_pre_select;
418 sct->task.post_select = command_post_select;
419 sct->argc = argc;
420 sct->argv = argv;
421 ret = para_listen_simple(IPPROTO_TCP, conf.port_arg);
422 if (ret < 0)
423 goto err;
424 sct->listen_fd = ret;
425 ret = mark_fd_nonblocking(sct->listen_fd);
426 if (ret < 0)
427 goto err;
428 add_close_on_fork_list(sct->listen_fd); /* child doesn't need the listener */
429 sprintf(sct->task.status, "server command task");
430 register_task(&sct->task);
431 return;
432 err:
433 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
434 exit(EXIT_FAILURE);
435 }
436
437 static int init_afs(void)
438 {
439 int ret, afs_server_socket[2];
440 pid_t afs_pid;
441
442 ret = socketpair(PF_UNIX, SOCK_DGRAM, 0, afs_server_socket);
443 if (ret < 0)
444 exit(EXIT_FAILURE);
445 get_random_bytes_or_die((unsigned char *)&afs_socket_cookie,
446 sizeof(afs_socket_cookie));
447 afs_pid = fork();
448 if (afs_pid < 0)
449 exit(EXIT_FAILURE);
450 if (afs_pid == 0) { /* child (afs) */
451 close(afs_server_socket[0]);
452 afs_init(afs_socket_cookie, afs_server_socket[1]);
453 }
454 mmd->afs_pid = afs_pid;
455 close(afs_server_socket[1]);
456 ret = mark_fd_nonblocking(afs_server_socket[0]);
457 if (ret < 0)
458 exit(EXIT_FAILURE);
459 add_close_on_fork_list(afs_server_socket[0]);
460 PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
461 afs_server_socket[0], (unsigned) afs_socket_cookie);
462 return afs_server_socket[0];
463 }
464
465 __noreturn static void tmp_sigchld_handler(__a_unused int s)
466 {
467 PARA_EMERG_LOG("caught early SIGCHLD\n");
468 exit(EXIT_FAILURE);
469 }
470
471 static void server_init(int argc, char **argv)
472 {
473 struct server_cmdline_parser_params params = {
474 .override = 0,
475 .initialize = 1,
476 .check_required = 0,
477 .check_ambiguity = 0,
478 .print_errors = 1
479 };
480 int afs_socket;
481
482 valid_fd_012();
483 init_random_seed_or_die();
484 /* parse command line options */
485 server_cmdline_parser_ext(argc, argv, &conf, &params);
486 HANDLE_VERSION_FLAG("server", conf);
487 drop_privileges_or_die(conf.user_arg, conf.group_arg);
488 /* parse config file, open log and set defaults */
489 parse_config_or_die(0);
490 log_welcome("para_server");
491 init_ipc_or_die(); /* init mmd struct and mmd->lock */
492 /* make sure, the global now pointer is uptodate */
493 gettimeofday(now, NULL);
494 set_server_start_time(now);
495 init_user_list(user_list_file);
496 init_server_command_task(argc, argv);
497 /* become daemon */
498 if (conf.daemon_given)
499 daemonize();
500 PARA_NOTICE_LOG("initializing audio format handlers\n");
501 afh_init();
502
503 /*
504 * Although afs uses its own signal handling we must ignore SIGUSR1
505 * _before_ the afs child process gets born by init_afs() below. It's
506 * racy to do this in the child because the parent might send SIGUSR1
507 * before the child gets a chance to ignore this signal -- only the
508 * good die young.
509 */
510 para_sigaction(SIGUSR1, SIG_IGN);
511 /*
512 * We have to install a SIGCHLD handler before the afs process is being
513 * forked off. Otherwise, para_server does not notice if afs dies before
514 * the SIGCHLD handler has been installed by init_signal_task() below.
515 */
516 para_sigaction(SIGCHLD, tmp_sigchld_handler);
517 PARA_NOTICE_LOG("initializing the audio file selector\n");
518 afs_socket = init_afs();
519 init_signal_task();
520 PARA_NOTICE_LOG("initializing virtual streaming system\n");
521 init_vss_task(afs_socket);
522 PARA_NOTICE_LOG("server init complete\n");
523 }
524
525 static void status_refresh(void)
526 {
527 static int prev_uptime = -1, prev_events = -1;
528 int uptime = get_server_uptime(now);
529
530 if (prev_events != mmd->events)
531 goto out;
532 if (mmd->new_vss_status_flags != mmd->vss_status_flags)
533 goto out_inc_events;
534 if (uptime / 60 != prev_uptime / 60)
535 goto out_inc_events;
536 return;
537 out_inc_events:
538 mmd->events++;
539 out:
540 prev_uptime = uptime;
541 prev_events = mmd->events;
542 mmd->vss_status_flags = mmd->new_vss_status_flags;
543 PARA_DEBUG_LOG("%d events, forcing status update\n", mmd->events);
544 killpg(0, SIGUSR1);
545 }
546
547 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
548 struct timeval *timeout_tv)
549 {
550 int ret;
551
552 status_refresh();
553 mutex_unlock(mmd_mutex);
554 ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
555 mutex_lock(mmd_mutex);
556 return ret;
557 }
558
559 /**
560 * The main function of para_server.
561 *
562 * \param argc Usual argument count.
563 * \param argv Usual argument vector.
564 *
565 * \return EXIT_SUCCESS or EXIT_FAILURE.
566 */
567 int main(int argc, char *argv[])
568 {
569 int ret;
570 static struct sched s = {
571 .default_timeout = {
572 .tv_sec = 1,
573 .tv_usec = 0
574 },
575 .select_function = server_select
576 };
577 server_init(argc, argv);
578 mutex_lock(mmd_mutex);
579 ret = schedule(&s);
580 if (ret < 0) {
581 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
582 exit(EXIT_FAILURE);
583 }
584 exit(EXIT_SUCCESS);
585 }