48ef55e84e7afdbbf13b4f0cd0383c1c837d60fc
[paraslash.git] / server.c
1 /*
2 * Copyright (C) 1997-2010 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 * - Hashing: \ref hash.h, \ref sha1.h, \ref sha1.c,
61 * - Crypto: \ref crypt.c.
62 * - Forward error correction: \ref fec.c.
63 */
64
65 #include <signal.h>
66 #include <dirent.h>
67 #include <sys/time.h>
68 #include <openssl/rc4.h>
69 #include <regex.h>
70 #include <osl.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
94 /** Define the array of error lists needed by para_server. */
95 INIT_SERVER_ERRLISTS;
96
97 /** Shut down non-authorized connections after that many seconds. */
98 #define ALARM_TIMEOUT 10
99
100 /**
101 * Pointer to shared memory area for communication between para_server
102 * and its children. Exported to vss.c. command.c and to afs.
103 */
104 struct misc_meta_data *mmd;
105
106 /**
107 * The configuration of para_server
108 *
109 * It also contains the options for the audio file selector, audio format
110 * handler and all supported senders.
111 */
112 struct server_args_info conf;
113
114 /** A random value used in child context for authentication. */
115 uint32_t afs_socket_cookie;
116
117 /** The mutex protecting the shared memory area containing the mmd struct. */
118 int mmd_mutex;
119
120 /** The file containing user information (public key, permissions). */
121 static char *user_list_file = NULL;
122
123
124 /** The task responsible for server command handling. */
125 struct server_command_task {
126 /** TCP port on which para_server listens for connections. */
127 int listen_fd;
128 /** Copied from para_server's main function. */
129 int argc;
130 /** Argument vector passed to para_server's main function. */
131 char **argv;
132 /** The command task structure for scheduling. */
133 struct task task;
134 };
135
136 static int want_colors(void)
137 {
138 if (conf.color_arg == color_arg_no)
139 return 0;
140 if (conf.color_arg == color_arg_yes)
141 return 1;
142 if (conf.logfile_given)
143 return 0;
144 return isatty(STDERR_FILENO);
145 }
146
147 static void init_colors_or_die(void)
148 {
149 int ret, i;
150
151 if (!want_colors())
152 return;
153 daemon_set_flag(DF_COLOR_LOG);
154 daemon_set_default_log_colors();
155 for (i = 0; i < conf.log_color_given; i++) {
156 ret = daemon_set_log_color(conf.log_color_arg[i]);
157 if (ret < 0)
158 exit(EXIT_FAILURE);
159 }
160 }
161
162 /*
163 * setup shared memory area and get mutex for locking
164 */
165 static void init_ipc_or_die(void)
166 {
167 void *shm;
168 int shmid, ret = shm_new(sizeof(struct misc_meta_data));
169
170 if (ret < 0)
171 goto err_out;
172 shmid = ret;
173 ret = shm_attach(shmid, ATTACH_RW, &shm);
174 shm_destroy(shmid);
175 if (ret < 0)
176 goto err_out;
177 mmd = shm;
178
179 ret = mutex_new();
180 if (ret < 0)
181 goto err_out;
182 mmd_mutex = ret;
183
184 mmd->num_played = 0;
185 mmd->num_commands = 0;
186 mmd->events = 0;
187 mmd->num_connects = 0;
188 mmd->active_connections = 0;
189 mmd->vss_status_flags = VSS_NEXT;
190 mmd->new_vss_status_flags = VSS_NEXT;
191 return;
192 err_out:
193 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
194 exit(EXIT_FAILURE);
195 }
196
197 /**
198 * (Re-)read the server configuration files.
199 *
200 * \param override Passed to gengetopt to activate the override feature.
201 *
202 * This function also re-opens the logfile and sets the global \a
203 * user_list_file variable.
204 */
205 void parse_config_or_die(int override)
206 {
207 char *home = para_homedir();
208 int ret;
209 char *cf;
210
211 daemon_close_log();
212 if (conf.config_file_given)
213 cf = para_strdup(conf.config_file_arg);
214 else
215 cf = make_message("%s/.paraslash/server.conf", home);
216 free(user_list_file);
217 if (!conf.user_list_given)
218 user_list_file = make_message("%s/.paraslash/server.users", home);
219 else
220 user_list_file = para_strdup(conf.user_list_arg);
221 ret = file_exists(cf);
222 if (conf.config_file_given && !ret) {
223 ret = -1;
224 PARA_EMERG_LOG("can not read config file %s\n", cf);
225 goto out;
226 }
227 if (ret) {
228 int tmp = conf.daemon_given;
229 struct server_cmdline_parser_params params = {
230 .override = override,
231 .initialize = 0,
232 .check_required = 1,
233 .check_ambiguity = 0,
234 .print_errors = !conf.daemon_given
235 };
236 server_cmdline_parser_config_file(cf, &conf, &params);
237 conf.daemon_given = tmp;
238 }
239 if (conf.logfile_given) {
240 daemon_set_logfile(conf.logfile_arg);
241 daemon_open_log_or_die();
242 }
243 daemon_set_loglevel(conf.loglevel_arg);
244 init_colors_or_die();
245 daemon_set_flag(DF_LOG_PID);
246 daemon_set_flag(DF_LOG_LL);
247 daemon_set_flag(DF_LOG_TIME);
248 if (conf.log_timing_given)
249 daemon_set_flag(DF_LOG_TIMING);
250 ret = 1;
251 out:
252 free(cf);
253 free(home);
254 if (ret > 0)
255 return;
256 free(user_list_file);
257 user_list_file = NULL;
258 exit(EXIT_FAILURE);
259 }
260
261 static void signal_pre_select(struct sched *s, struct task *t)
262 {
263 struct signal_task *st = container_of(t, struct signal_task, task);
264 para_fd_set(st->fd, &s->rfds, &s->max_fileno);
265 }
266
267 /*
268 * called when server gets SIGHUP or when client invokes hup command.
269 */
270 static void handle_sighup(void)
271 {
272 PARA_NOTICE_LOG("SIGHUP\n");
273 parse_config_or_die(1); /* reopens log */
274 init_user_list(user_list_file); /* reload user list */
275 if (mmd->afs_pid)
276 kill(mmd->afs_pid, SIGHUP);
277 }
278
279 static void signal_post_select(struct sched *s, __a_unused struct task *t)
280 {
281 int signum = para_next_signal(&s->rfds);
282
283 switch (signum) {
284 case 0:
285 return;
286 case SIGHUP:
287 handle_sighup();
288 break;
289 case SIGCHLD:
290 for (;;) {
291 pid_t pid;
292 int ret = para_reap_child(&pid);
293 if (ret <= 0)
294 break;
295 if (pid != mmd->afs_pid)
296 continue;
297 PARA_EMERG_LOG("fatal: afs died\n");
298 kill(0, SIGTERM);
299 goto cleanup;
300 }
301 break;
302 /* die on sigint/sigterm. Kill all children too. */
303 case SIGINT:
304 case SIGTERM:
305 PARA_EMERG_LOG("terminating on signal %d\n", signum);
306 kill(0, SIGTERM);
307 /*
308 * We must wait for afs because afs catches SIGINT/SIGTERM.
309 * Before reacting to the signal, afs might want to use the
310 * shared memory area and the mmd mutex. If we destroy this
311 * mutex too early and afs tries to lock the shared memory
312 * area, the call to mutex_lock() will fail and terminate the
313 * afs process. This leads to dirty osl tables.
314 *
315 * There's no such problem with the other children of the
316 * server process (the command handlers) as these reset their
317 * SIGINT/SIGTERM handlers to the default action, i.e. these
318 * processes get killed immediately by the above kill().
319 */
320 PARA_INFO_LOG("waiting for afs (pid %d) to die\n",
321 (int)mmd->afs_pid);
322 waitpid(mmd->afs_pid, NULL, 0);
323 cleanup:
324 free(mmd->afd.afhi.chunk_table);
325 close_listed_fds();
326 mutex_destroy(mmd_mutex);
327 shm_detach(mmd);
328 exit(EXIT_FAILURE);
329 }
330 }
331
332 static void init_signal_task(void)
333 {
334 static struct signal_task signal_task_struct,
335 *st = &signal_task_struct;
336
337 st->task.pre_select = signal_pre_select;
338 st->task.post_select = signal_post_select;
339 sprintf(st->task.status, "signal task");
340
341 PARA_NOTICE_LOG("setting up signal handling\n");
342 st->fd = para_signal_init(); /* always successful */
343 para_install_sighandler(SIGINT);
344 para_install_sighandler(SIGTERM);
345 para_install_sighandler(SIGHUP);
346 para_install_sighandler(SIGCHLD);
347 para_sigaction(SIGPIPE, SIG_IGN);
348 add_close_on_fork_list(st->fd);
349 register_task(&st->task);
350 }
351
352 static void command_pre_select(struct sched *s, struct task *t)
353 {
354 struct server_command_task *sct = container_of(t, struct server_command_task, task);
355 para_fd_set(sct->listen_fd, &s->rfds, &s->max_fileno);
356 }
357
358 static void command_post_select(struct sched *s, struct task *t)
359 {
360 struct server_command_task *sct = container_of(t, struct server_command_task, task);
361
362 int new_fd, ret, i;
363 char *peer_name;
364 pid_t child_pid;
365 uint32_t *chunk_table;
366
367 ret = para_accept(sct->listen_fd, &s->rfds, NULL, 0, &new_fd);
368 if (ret <= 0)
369 goto out;
370 peer_name = remote_name(new_fd);
371 PARA_INFO_LOG("got connection from %s, forking\n", peer_name);
372 mmd->num_connects++;
373 mmd->active_connections++;
374 /*
375 * The chunk table is a pointer located in the mmd struct that points
376 * to dynamically allocated memory, i.e. it must be freed by the parent
377 * and the child. However, as the mmd struct is in a shared memory
378 * area, there's no guarantee that after the fork this pointer is still
379 * valid in child context. As it is not used in the child anyway, we
380 * save it to a local variable before the fork and free the memory via
381 * that copy in the child directly after the fork.
382 */
383 chunk_table = mmd->afd.afhi.chunk_table;
384 child_pid = fork();
385 if (child_pid < 0) {
386 ret = -ERRNO_TO_PARA_ERROR(errno);
387 goto out;
388 }
389 if (child_pid) {
390 close(new_fd);
391 /* parent keeps accepting connections */
392 return;
393 }
394 /* mmd might already have changed at this point */
395 free(chunk_table);
396 alarm(ALARM_TIMEOUT);
397 close_listed_fds();
398 para_signal_shutdown();
399 /*
400 * put info on who we are serving into argv[0] to make
401 * client ip visible in top/ps
402 */
403 for (i = sct->argc - 1; i >= 0; i--)
404 memset(sct->argv[i], 0, strlen(sct->argv[i]));
405 sprintf(sct->argv[0], "para_server (serving %s)", peer_name);
406 return handle_connect(new_fd, peer_name);
407 out:
408 if (ret < 0)
409 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
410 }
411
412 static void init_server_command_task(int argc, char **argv)
413 {
414 int ret;
415 static struct server_command_task server_command_task_struct,
416 *sct = &server_command_task_struct;
417
418 PARA_NOTICE_LOG("initializing tcp command socket\n");
419 sct->task.pre_select = command_pre_select;
420 sct->task.post_select = command_post_select;
421 sct->argc = argc;
422 sct->argv = argv;
423 ret = para_listen_simple(IPPROTO_TCP, conf.port_arg);
424 if (ret < 0)
425 goto err;
426 sct->listen_fd = ret;
427 ret = mark_fd_nonblocking(sct->listen_fd);
428 if (ret < 0)
429 goto err;
430 add_close_on_fork_list(sct->listen_fd); /* child doesn't need the listener */
431 register_task(&sct->task);
432 return;
433 err:
434 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
435 exit(EXIT_FAILURE);
436 }
437
438 static int init_afs(void)
439 {
440 int ret, afs_server_socket[2];
441 pid_t afs_pid;
442
443 ret = socketpair(PF_UNIX, SOCK_DGRAM, 0, afs_server_socket);
444 if (ret < 0)
445 exit(EXIT_FAILURE);
446 get_random_bytes_or_die((unsigned char *)&afs_socket_cookie,
447 sizeof(afs_socket_cookie));
448 afs_pid = fork();
449 if (afs_pid < 0)
450 exit(EXIT_FAILURE);
451 if (afs_pid == 0) { /* child (afs) */
452 close(afs_server_socket[0]);
453 afs_init(afs_socket_cookie, afs_server_socket[1]);
454 }
455 mmd->afs_pid = afs_pid;
456 close(afs_server_socket[1]);
457 ret = mark_fd_nonblocking(afs_server_socket[0]);
458 if (ret < 0)
459 exit(EXIT_FAILURE);
460 add_close_on_fork_list(afs_server_socket[0]);
461 PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
462 afs_server_socket[0], (unsigned) afs_socket_cookie);
463 return afs_server_socket[0];
464 }
465
466 __noreturn static void tmp_sigchld_handler(__a_unused int s)
467 {
468 PARA_EMERG_LOG("caught early SIGCHLD\n");
469 exit(EXIT_FAILURE);
470 }
471
472 static void server_init(int argc, char **argv)
473 {
474 struct server_cmdline_parser_params params = {
475 .override = 0,
476 .initialize = 1,
477 .check_required = 0,
478 .check_ambiguity = 0,
479 .print_errors = 1
480 };
481 int afs_socket;
482
483 valid_fd_012();
484 init_random_seed_or_die();
485 /* parse command line options */
486 server_cmdline_parser_ext(argc, argv, &conf, &params);
487 HANDLE_VERSION_FLAG("server", conf);
488 drop_privileges_or_die(conf.user_arg, conf.group_arg);
489 /* parse config file, open log and set defaults */
490 parse_config_or_die(0);
491 log_welcome("para_server");
492 init_ipc_or_die(); /* init mmd struct and mmd->lock */
493 /* make sure, the global now pointer is uptodate */
494 gettimeofday(now, NULL);
495 server_uptime(UPTIME_SET); /* reset server uptime */
496 init_user_list(user_list_file);
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 init_server_command_task(argc, argv);
523 PARA_NOTICE_LOG("server init complete\n");
524 }
525
526 static void status_refresh(void)
527 {
528 static int prev_uptime = -1, prev_events = -1;
529 int uptime = server_uptime(UPTIME_GET), ret = 1;
530
531 if (prev_events != mmd->events)
532 goto out;
533 if (mmd->new_vss_status_flags != mmd->vss_status_flags)
534 goto out_inc_events;
535 if (uptime / 60 != prev_uptime / 60)
536 goto out_inc_events;
537 return;
538 out_inc_events:
539 mmd->events++;
540 out:
541 prev_uptime = uptime;
542 prev_events = mmd->events;
543 mmd->vss_status_flags = mmd->new_vss_status_flags;
544 if (ret) {
545 PARA_DEBUG_LOG("%d events, forcing status update\n",
546 mmd->events);
547 killpg(0, SIGUSR1);
548 }
549 }
550
551 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
552 struct timeval *timeout_tv)
553 {
554 int ret;
555
556 status_refresh();
557 mutex_unlock(mmd_mutex);
558 ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
559 mutex_lock(mmd_mutex);
560 return ret;
561 }
562
563 /**
564 * The main function of para_server.
565 *
566 * \param argc Usual argument count.
567 * \param argv Usual argument vector.
568 *
569 * \return EXIT_SUCCESS or EXIT_FAILURE.
570 */
571 int main(int argc, char *argv[])
572 {
573 int ret;
574 static struct sched s = {
575 .default_timeout = {
576 .tv_sec = 1,
577 .tv_usec = 0
578 },
579 .select_function = server_select
580 };
581 server_init(argc, argv);
582 mutex_lock(mmd_mutex);
583 ret = schedule(&s);
584 if (ret < 0) {
585 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
586 exit(EXIT_FAILURE);
587 }
588 exit(EXIT_SUCCESS);
589 }