Merge commit 'meins/maint' into maint
[paraslash.git] / server.c
1 /*
2 * Copyright (C) 1997-2009 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 fsck.c, \ref afh.c
18 * - Server: \ref server_command, \ref sender,
19 * - Audio file selector: \ref audio_format_handler, \ref mood, \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, \ref ogg_afh.c, \ref aac_afh.c,
26 * - Decoders: \ref mp3dec_filter.c, \ref oggdec_filter.c, \ref aacdec_filter.c,
27 * - Volume normalizer: \ref compress_filter.c,
28 * - Output: \ref alsa_write.c, \ref osx_write.c,
29 * - http: \ref http_recv.c, \ref http_send.c,
30 * - udp: \ref udp_recv.c, \ref udp_send.c,
31 * - dccp: \ref dccp_recv.c, \ref dccp_send.c,
32 * - Audio file selector: \ref afs.c, \ref aft.c, \ref mood.c,
33 * - Afs structures: \ref afs_table, \ref audio_file_data,
34 * \ref afs_info \ref afh_info,
35 * - Afs tables: \ref aft.c, \ref mood.c, \ref playlist.c,
36 * \ref attribute.c, \ref score.c,
37 * - The virtual streaming system: \ref vss.c, \ref chunk_queue.c.
38 *
39 * Lower levels:
40 *
41 * - Scheduling: \ref sched.c, \ref sched.h,
42 * - Networking: \ref net.c,
43 * - File descriptors: \ref fd.c,
44 * - Signals: \ref signal.c,
45 * - Daemons: \ref daemon.c,
46 * - Strings: \ref string.c, \ref string.h,
47 * - Time: \ref time.c,
48 * - Spawning processes: \ref exec.c,
49 * - Inter process communication: \ref ipc.c,
50 * - The object storage layer: \ref osl.c,
51 * - Blob tables: \ref blob.c,
52 * - The error subssystem: \ref error.h.
53 * - Access control for paraslash senders: \ref acl.c, \ref acl.h.
54 *
55 * Low-level data structures:
56 *
57 * - Doubly linked lists: \ref list.h,
58 * - Red-black trees: \ref rbtree.h, \ref rbtree.c,
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
69 #include "para.h"
70 #include "error.h"
71 #include "server.cmdline.h"
72 #include "afh.h"
73 #include "string.h"
74 #include "afs.h"
75 #include "server.h"
76 #include "vss.h"
77 #include "config.h"
78 #include "close_on_fork.h"
79 #include "list.h"
80 #include "send.h"
81 #include "net.h"
82 #include "daemon.h"
83 #include "ipc.h"
84 #include "fd.h"
85 #include "sched.h"
86 #include "signal.h"
87 #include "user_list.h"
88 #include "color.h"
89
90 /** Define the array of error lists needed by para_server. */
91 INIT_SERVER_ERRLISTS;
92
93 /** Shut down non-authorized connections after that many seconds. */
94 #define ALARM_TIMEOUT 10
95
96 /**
97 * Pointer to shared memory area for communication between para_server
98 * and its children. Exported to vss.c. command.c and to afs.
99 */
100 struct misc_meta_data *mmd;
101
102 /**
103 * The configuration of para_server
104 *
105 * It also contains the options for the audio file selector, audio format
106 * handler and all supported senders.
107 */
108 struct server_args_info conf;
109
110 /** A random value used in child context for authentication. */
111 uint32_t afs_socket_cookie;
112
113 /** The mutex protecting the shared memory area containing the mmd struct. */
114 int mmd_mutex;
115
116 /** The file containing user information (public key, permissions). */
117 static char *user_list_file = NULL;
118
119
120 /** The task responsible for server command handling. */
121 struct server_command_task {
122 /** TCP port on which para_server listens for connections. */
123 int listen_fd;
124 /** Copied from para_server's main function. */
125 int argc;
126 /** Argument vector passed to para_server's main function. */
127 char **argv;
128 /** The command task structure for scheduling. */
129 struct task task;
130 };
131
132 static int want_colors(void)
133 {
134 if (conf.color_arg == color_arg_no)
135 return 0;
136 if (conf.color_arg == color_arg_yes)
137 return 1;
138 if (conf.logfile_given)
139 return 0;
140 return isatty(STDERR_FILENO);
141 }
142
143 static void init_colors_or_die(void)
144 {
145 int ret, i;
146
147 if (!want_colors())
148 return;
149 daemon_set_flag(DF_COLOR_LOG);
150 daemon_set_default_log_colors();
151 for (i = 0; i < conf.log_color_given; i++) {
152 ret = daemon_set_log_color(conf.log_color_arg[i]);
153 if (ret < 0)
154 exit(EXIT_FAILURE);
155 }
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 ret = 1;
245 out:
246 free(cf);
247 free(home);
248 if (ret > 0)
249 return;
250 free(user_list_file);
251 user_list_file = NULL;
252 exit(EXIT_FAILURE);
253 }
254
255 static void signal_pre_select(struct sched *s, struct task *t)
256 {
257 struct signal_task *st = container_of(t, struct signal_task, task);
258 para_fd_set(st->fd, &s->rfds, &s->max_fileno);
259 }
260
261 /*
262 * called when server gets SIGHUP or when client invokes hup command.
263 */
264 static void handle_sighup(void)
265 {
266 PARA_NOTICE_LOG("SIGHUP\n");
267 parse_config_or_die(1); /* reopens log */
268 init_user_list(user_list_file); /* reload user list */
269 if (mmd->afs_pid)
270 kill(mmd->afs_pid, SIGHUP);
271 }
272
273 static void signal_post_select(struct sched *s, struct task *t)
274 {
275 struct signal_task *st = container_of(t, struct signal_task, task);
276
277 if (!FD_ISSET(st->fd, &s->rfds))
278 return;
279
280 st->signum = para_next_signal();
281 switch (st->signum) {
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", st->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 free(mmd->afd.afhi.info_string);
322 close_listed_fds();
323 mutex_destroy(mmd_mutex);
324 shm_detach(mmd);
325 exit(EXIT_FAILURE);
326 }
327 }
328
329 static void init_signal_task(void)
330 {
331 static struct signal_task signal_task_struct,
332 *st = &signal_task_struct;
333
334 st->task.pre_select = signal_pre_select;
335 st->task.post_select = signal_post_select;
336 sprintf(st->task.status, "signal task");
337
338 PARA_NOTICE_LOG("setting up signal handling\n");
339 st->fd = para_signal_init(); /* always successful */
340 para_install_sighandler(SIGINT);
341 para_install_sighandler(SIGTERM);
342 para_install_sighandler(SIGHUP);
343 para_install_sighandler(SIGCHLD);
344 para_sigaction(SIGPIPE, SIG_IGN);
345 add_close_on_fork_list(st->fd);
346 register_task(&st->task);
347 }
348
349 static void command_pre_select(struct sched *s, struct task *t)
350 {
351 struct server_command_task *sct = container_of(t, struct server_command_task, task);
352 para_fd_set(sct->listen_fd, &s->rfds, &s->max_fileno);
353 }
354
355 static void command_post_select(struct sched *s, struct task *t)
356 {
357 struct server_command_task *sct = container_of(t, struct server_command_task, task);
358
359 int new_fd, ret, i;
360 char *peer_name;
361 pid_t child_pid;
362 uint32_t *chunk_table;
363 char *info_string;
364
365 if (!FD_ISSET(sct->listen_fd, &s->rfds))
366 return;
367 ret = para_accept(sct->listen_fd, NULL, 0);
368 if (ret < 0)
369 goto out;
370 new_fd = ret;
371 peer_name = remote_name(new_fd);
372 PARA_INFO_LOG("got connection from %s, forking\n", peer_name);
373 mmd->num_connects++;
374 mmd->active_connections++;
375 random();
376 /* The chunk table and the info_string are pointers located in the
377 * mmd struct that point to dynamically allocated memory that must be
378 * freed by the parent and the child. However, as the mmd struct is in
379 * a shared memory area, there's no guarantee that after the fork these
380 * pointers are still valid in child context. As these two pointers are
381 * not used in the child anyway, we save them to local variables and
382 * free the memory via that copy in the child.
383 */
384 info_string = mmd->afd.afhi.info_string;
385 chunk_table = mmd->afd.afhi.chunk_table;
386 child_pid = fork();
387 if (child_pid < 0) {
388 ret = -ERRNO_TO_PARA_ERROR(errno);
389 goto out;
390 }
391 if (child_pid) {
392 close(new_fd);
393 /* parent keeps accepting connections */
394 return;
395 }
396 /* mmd might already have changed at this point */
397 free(info_string);
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 return handle_connect(new_fd, peer_name);
410 out:
411 if (ret < 0)
412 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
413 }
414
415 static void init_server_command_task(int argc, char **argv)
416 {
417 int ret;
418 static struct server_command_task server_command_task_struct,
419 *sct = &server_command_task_struct;
420
421 PARA_NOTICE_LOG("initializing tcp command socket\n");
422 sct->task.pre_select = command_pre_select;
423 sct->task.post_select = command_post_select;
424 sct->argc = argc;
425 sct->argv = argv;
426 ret = para_listen(AF_UNSPEC, IPPROTO_TCP, conf.port_arg);
427 if (ret < 0)
428 goto err;
429 sct->listen_fd = ret;
430 ret = mark_fd_nonblocking(sct->listen_fd);
431 if (ret < 0)
432 goto err;
433 add_close_on_fork_list(sct->listen_fd); /* child doesn't need the listener */
434 register_task(&sct->task);
435 return;
436 err:
437 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
438 exit(EXIT_FAILURE);
439 }
440
441 static void init_random_seed(void)
442 {
443 unsigned int seed;
444 int fd, ret = para_open("/dev/urandom", O_RDONLY, 0);
445
446 if (ret < 0)
447 goto err;
448 fd = ret;
449 ret = read(fd, &seed, sizeof(seed));
450 if (ret < 0) {
451 ret = -ERRNO_TO_PARA_ERROR(errno);
452 goto out;
453 }
454 if (ret != sizeof(seed)) {
455 ret = -ERRNO_TO_PARA_ERROR(EIO);
456 goto out;
457 }
458 srandom(seed);
459 ret = 1;
460 out:
461 close(fd);
462 if (ret >= 0)
463 return;
464 err:
465 PARA_EMERG_LOG("can not seed pseudo random number generator: %s\n",
466 para_strerror(-ret));
467 exit(EXIT_FAILURE);
468 }
469
470 static int init_afs(void)
471 {
472 int ret, afs_server_socket[2];
473 pid_t afs_pid;
474
475 ret = socketpair(PF_UNIX, SOCK_DGRAM, 0, afs_server_socket);
476 if (ret < 0)
477 exit(EXIT_FAILURE);
478 afs_socket_cookie = para_random((uint32_t)-1);
479 afs_pid = fork();
480 if (afs_pid < 0)
481 exit(EXIT_FAILURE);
482 if (afs_pid == 0) { /* child (afs) */
483 close(afs_server_socket[0]);
484 afs_init(afs_socket_cookie, afs_server_socket[1]);
485 }
486 mmd->afs_pid = afs_pid;
487 close(afs_server_socket[1]);
488 ret = mark_fd_nonblocking(afs_server_socket[0]);
489 if (ret < 0)
490 exit(EXIT_FAILURE);
491 add_close_on_fork_list(afs_server_socket[0]);
492 PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
493 afs_server_socket[0], (unsigned) afs_socket_cookie);
494 return afs_server_socket[0];
495 }
496
497 __noreturn static void tmp_sigchld_handler(__a_unused int s)
498 {
499 PARA_EMERG_LOG("caught early SIGCHLD\n");
500 exit(EXIT_FAILURE);
501 }
502
503 static void server_init(int argc, char **argv)
504 {
505 struct server_cmdline_parser_params params = {
506 .override = 0,
507 .initialize = 1,
508 .check_required = 0,
509 .check_ambiguity = 0,
510 .print_errors = 1
511 };
512 int afs_socket;
513
514 valid_fd_012();
515 init_random_seed();
516 /* parse command line options */
517 server_cmdline_parser_ext(argc, argv, &conf, &params);
518 HANDLE_VERSION_FLAG("server", conf);
519 drop_privileges_or_die(conf.user_arg, conf.group_arg);
520 /* parse config file, open log and set defaults */
521 parse_config_or_die(0);
522 log_welcome("para_server");
523 init_ipc_or_die(); /* init mmd struct and mmd->lock */
524 /* make sure, the global now pointer is uptodate */
525 gettimeofday(now, NULL);
526 server_uptime(UPTIME_SET); /* reset server uptime */
527 init_user_list(user_list_file);
528 /* become daemon */
529 if (conf.daemon_given)
530 daemonize();
531 PARA_NOTICE_LOG("initializing audio format handlers\n");
532 afh_init();
533
534 /*
535 * Although afs uses its own signal handling we must ignore SIGUSR1
536 * _before_ the afs child process gets born by init_afs() below. It's
537 * racy to do this in the child because the parent might send SIGUSR1
538 * before the child gets a chance to ignore this signal -- only the
539 * good die young.
540 */
541 para_sigaction(SIGUSR1, SIG_IGN);
542 /*
543 * We have to install a SIGCHLD handler before the afs process is being
544 * forked off. Otherwise, para_server does not notice if afs dies before
545 * the SIGCHLD handler has been installed by init_signal_task() below.
546 */
547 para_sigaction(SIGCHLD, tmp_sigchld_handler);
548 PARA_NOTICE_LOG("initializing the audio file selector\n");
549 afs_socket = init_afs();
550 init_signal_task();
551 PARA_NOTICE_LOG("initializing virtual streaming system\n");
552 init_vss_task(afs_socket);
553 init_server_command_task(argc, argv);
554 PARA_NOTICE_LOG("server init complete\n");
555 }
556
557 static void status_refresh(void)
558 {
559 static int prev_uptime = -1, prev_events = -1;
560 int uptime = server_uptime(UPTIME_GET), ret = 1;
561
562 if (prev_events != mmd->events)
563 goto out;
564 if (mmd->new_vss_status_flags != mmd->vss_status_flags)
565 goto out_inc_events;
566 if (uptime / 60 != prev_uptime / 60)
567 goto out_inc_events;
568 return;
569 out_inc_events:
570 mmd->events++;
571 out:
572 prev_uptime = uptime;
573 prev_events = mmd->events;
574 mmd->vss_status_flags = mmd->new_vss_status_flags;
575 if (ret) {
576 PARA_DEBUG_LOG("%d events, forcing status update\n",
577 mmd->events);
578 killpg(0, SIGUSR1);
579 }
580 }
581
582 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
583 struct timeval *timeout_tv)
584 {
585 int ret;
586
587 status_refresh();
588 mutex_unlock(mmd_mutex);
589 ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
590 mutex_lock(mmd_mutex);
591 return ret;
592 }
593
594 /**
595 * The main function of para_server.
596 *
597 * \param argc Usual argument count.
598 * \param argv Usual argument vector.
599 *
600 * \return EXIT_SUCCESS or EXIT_FAILURE.
601 */
602 int main(int argc, char *argv[])
603 {
604 int ret;
605 static struct sched s = {
606 .default_timeout = {
607 .tv_sec = 1,
608 .tv_usec = 0
609 },
610 .select_function = server_select
611 };
612 server_init(argc, argv);
613 mutex_lock(mmd_mutex);
614 ret = schedule(&s);
615 if (ret < 0) {
616 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
617 exit(EXIT_FAILURE);
618 }
619 exit(EXIT_SUCCESS);
620 }