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