client: Fix return value check for sb_received().
[paraslash.git] / server.c
1 /*
2 * Copyright (C) 1997 Andre Noll <maan@tuebingen.mpg.de>
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 * \mainpage Main data structures:
11 *
12 * - Server: \ref server_command, \ref sender,
13 * - Audio file selector: \ref afs_info, \ref afs_table,
14 * - Audio format handler: \ref audio_format_handler, \ref afh_info
15 * - Receivers/filters/writers: \ref receiver, \ref receiver_node,
16 * \ref filter, \ref filter_node, \ref writer_node, \ref writer.
17 *
18 * Selected APIs:
19 *
20 * - Scheduling: \ref sched.h,
21 * - Buffer trees: \ref buffer_tree.h,
22 * - Sideband API: \ref sideband.h,
23 * - Crypto: \ref crypt.h, \ref crypt_backend.h,
24 * - Error subsystem: \ref error.h, \ref error2.c,
25 * - Inter process communication: \ref ipc.h,
26 * - Forward error correction: \ref fec.h,
27 * - Daemons: \ref daemon.h,
28 * - Mixer API: \ref mix.h,
29 * - Interactive sessions: \ref interactive.h,
30 * - File descriptors: \ref fd.h,
31 * - Signals: \ref signal.h,
32 * - Networking: \ref net.h,
33 * - Time: \ref time.c,
34 * - Doubly linked lists: \ref list.h.
35 */
36
37 #include <netinet/in.h>
38 #include <sys/socket.h>
39 #include <signal.h>
40 #include <regex.h>
41 #include <osl.h>
42 #include <sys/types.h>
43 #include <arpa/inet.h>
44 #include <sys/un.h>
45 #include <netdb.h>
46
47 #include "para.h"
48 #include "error.h"
49 #include "crypt.h"
50 #include "server.cmdline.h"
51 #include "afh.h"
52 #include "string.h"
53 #include "afs.h"
54 #include "server.h"
55 #include "list.h"
56 #include "send.h"
57 #include "sched.h"
58 #include "vss.h"
59 #include "config.h"
60 #include "close_on_fork.h"
61 #include "net.h"
62 #include "daemon.h"
63 #include "ipc.h"
64 #include "fd.h"
65 #include "signal.h"
66 #include "user_list.h"
67 #include "color.h"
68 #include "ggo.h"
69 #include "version.h"
70
71 __printf_2_3 void (*para_log)(int, const char*, ...) = daemon_log;
72
73 /** Define the array of error lists needed by para_server. */
74 INIT_SERVER_ERRLISTS;
75
76 /** Shut down non-authorized connections after that many seconds. */
77 #define ALARM_TIMEOUT 10
78
79 /**
80 * Pointer to shared memory area for communication between para_server
81 * and its children. Exported to vss.c. command.c and to afs.
82 */
83 struct misc_meta_data *mmd;
84
85 /**
86 * The configuration of para_server
87 *
88 * It also contains the options for the audio file selector, audio format
89 * handler and all supported senders.
90 */
91 struct server_args_info conf;
92
93 /** A random value used in child context for authentication. */
94 uint32_t afs_socket_cookie;
95
96 /** The mutex protecting the shared memory area containing the mmd struct. */
97 int mmd_mutex;
98
99 /** The file containing user information (public key, permissions). */
100 static char *user_list_file = NULL;
101
102 static struct sched sched;
103
104 /** The task responsible for server command handling. */
105 struct server_command_task {
106 /** TCP port on which para_server listens for connections. */
107 int listen_fd;
108 /** Copied from para_server's main function. */
109 int argc;
110 /** Argument vector passed to para_server's main function. */
111 char **argv;
112 /** The command task structure for scheduling. */
113 struct task *task;
114 };
115
116 /**
117 * Return the list of tasks for the server process.
118 *
119 * This is called from \a com_tasks(). The helper is necessary since command
120 * handlers can not access the scheduler structure directly.
121 *
122 * \return A dynamically allocated string that must be freed by the caller.
123 */
124 char *server_get_tasks(void)
125 {
126 return get_task_list(&sched);
127 }
128
129 static int want_colors(void)
130 {
131 if (conf.color_arg == color_arg_no)
132 return 0;
133 if (conf.color_arg == color_arg_yes)
134 return 1;
135 if (conf.logfile_given)
136 return 0;
137 return isatty(STDERR_FILENO);
138 }
139
140 static void init_colors_or_die(void)
141 {
142 int i;
143
144 if (!want_colors())
145 return;
146 daemon_set_flag(DF_COLOR_LOG);
147 daemon_set_default_log_colors();
148 for (i = 0; i < conf.log_color_given; i++)
149 daemon_set_log_color_or_die(conf.log_color_arg[i]);
150 }
151
152 /*
153 * setup shared memory area and get mutex for locking
154 */
155 static void init_ipc_or_die(void)
156 {
157 void *shm;
158 int shmid, ret = shm_new(sizeof(struct misc_meta_data));
159
160 if (ret < 0)
161 goto err_out;
162 shmid = ret;
163 ret = shm_attach(shmid, ATTACH_RW, &shm);
164 shm_destroy(shmid);
165 if (ret < 0)
166 goto err_out;
167 mmd = shm;
168
169 ret = mutex_new();
170 if (ret < 0)
171 goto err_out;
172 mmd_mutex = ret;
173
174 mmd->num_played = 0;
175 mmd->num_commands = 0;
176 mmd->events = 0;
177 mmd->num_connects = 0;
178 mmd->active_connections = 0;
179 mmd->vss_status_flags = VSS_NEXT;
180 mmd->new_vss_status_flags = VSS_NEXT;
181 return;
182 err_out:
183 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
184 exit(EXIT_FAILURE);
185 }
186
187 /**
188 * (Re-)read the server configuration files.
189 *
190 * \param override Passed to gengetopt to activate the override feature.
191 *
192 * This function also re-opens the logfile and sets the global \a
193 * user_list_file variable.
194 */
195 void parse_config_or_die(int override)
196 {
197 char *home = para_homedir();
198 int ret;
199 char *cf;
200
201 daemon_close_log();
202 if (conf.config_file_given)
203 cf = para_strdup(conf.config_file_arg);
204 else
205 cf = make_message("%s/.paraslash/server.conf", home);
206 free(user_list_file);
207 if (!conf.user_list_given)
208 user_list_file = make_message("%s/.paraslash/server.users", home);
209 else
210 user_list_file = para_strdup(conf.user_list_arg);
211 ret = file_exists(cf);
212 if (conf.config_file_given && !ret) {
213 ret = -1;
214 PARA_EMERG_LOG("can not read config file %s\n", cf);
215 goto out;
216 }
217 if (ret) {
218 int tmp = conf.daemon_given;
219 struct server_cmdline_parser_params params = {
220 .override = override,
221 .initialize = 0,
222 .check_required = 1,
223 .check_ambiguity = 0,
224 .print_errors = !conf.daemon_given
225 };
226 server_cmdline_parser_config_file(cf, &conf, &params);
227 daemon_set_loglevel(conf.loglevel_arg);
228 conf.daemon_given = tmp;
229 }
230 if (conf.logfile_given) {
231 daemon_set_logfile(conf.logfile_arg);
232 daemon_open_log_or_die();
233 }
234 init_colors_or_die();
235 daemon_set_flag(DF_LOG_PID);
236 daemon_set_flag(DF_LOG_LL);
237 daemon_set_flag(DF_LOG_TIME);
238 if (conf.log_timing_given)
239 daemon_set_flag(DF_LOG_TIMING);
240 ret = 1;
241 out:
242 free(cf);
243 free(home);
244 if (ret > 0)
245 return;
246 free(user_list_file);
247 user_list_file = NULL;
248 exit(EXIT_FAILURE);
249 }
250
251 static void signal_pre_select(struct sched *s, void *context)
252 {
253 struct signal_task *st = context;
254 para_fd_set(st->fd, &s->rfds, &s->max_fileno);
255 }
256
257 /*
258 * called when server gets SIGHUP or when client invokes hup command.
259 */
260 static void handle_sighup(void)
261 {
262 PARA_NOTICE_LOG("SIGHUP\n");
263 parse_config_or_die(1); /* reopens log */
264 init_user_list(user_list_file); /* reload user list */
265 if (mmd->afs_pid)
266 kill(mmd->afs_pid, SIGHUP);
267 }
268
269 static int signal_post_select(struct sched *s, __a_unused void *context)
270 {
271 int signum = para_next_signal(&s->rfds);
272
273 switch (signum) {
274 case 0:
275 return 0;
276 case SIGHUP:
277 handle_sighup();
278 break;
279 case SIGCHLD:
280 for (;;) {
281 pid_t pid;
282 int ret = para_reap_child(&pid);
283 if (ret <= 0)
284 break;
285 if (pid != mmd->afs_pid)
286 continue;
287 PARA_EMERG_LOG("fatal: afs died\n");
288 kill(0, SIGTERM);
289 goto cleanup;
290 }
291 break;
292 /* die on sigint/sigterm. Kill all children too. */
293 case SIGINT:
294 case SIGTERM:
295 PARA_EMERG_LOG("terminating on signal %d\n", signum);
296 kill(0, SIGTERM);
297 /*
298 * We must wait for afs because afs catches SIGINT/SIGTERM.
299 * Before reacting to the signal, afs might want to use the
300 * shared memory area and the mmd mutex. If we destroy this
301 * mutex too early and afs tries to lock the shared memory
302 * area, the call to mutex_lock() will fail and terminate the
303 * afs process. This leads to dirty osl tables.
304 *
305 * There's no such problem with the other children of the
306 * server process (the command handlers) as these reset their
307 * SIGINT/SIGTERM handlers to the default action, i.e. these
308 * processes get killed immediately by the above kill().
309 */
310 PARA_INFO_LOG("waiting for afs (pid %d) to die\n",
311 (int)mmd->afs_pid);
312 waitpid(mmd->afs_pid, NULL, 0);
313 cleanup:
314 free(mmd->afd.afhi.chunk_table);
315 close_listed_fds();
316 mutex_destroy(mmd_mutex);
317 shm_detach(mmd);
318 exit(EXIT_FAILURE);
319 }
320 return 0;
321 }
322
323 static void init_signal_task(void)
324 {
325 static struct signal_task signal_task_struct,
326 *st = &signal_task_struct;
327
328 PARA_NOTICE_LOG("setting up signal handling\n");
329 st->fd = para_signal_init(); /* always successful */
330 para_install_sighandler(SIGINT);
331 para_install_sighandler(SIGTERM);
332 para_install_sighandler(SIGHUP);
333 para_install_sighandler(SIGCHLD);
334 para_sigaction(SIGPIPE, SIG_IGN);
335 add_close_on_fork_list(st->fd);
336 st->task = task_register(&(struct task_info) {
337 .name = "signal",
338 .pre_select = signal_pre_select,
339 .post_select = signal_post_select,
340 .context = st,
341
342 }, &sched);
343 }
344
345 static void command_pre_select(struct sched *s, void *context)
346 {
347 struct server_command_task *sct = context;
348 para_fd_set(sct->listen_fd, &s->rfds, &s->max_fileno);
349 }
350
351 static int command_post_select(struct sched *s, void *context)
352 {
353 struct server_command_task *sct = context;
354
355 int new_fd, ret, i;
356 char *peer_name;
357 pid_t child_pid;
358 uint32_t *chunk_table;
359
360 ret = para_accept(sct->listen_fd, &s->rfds, NULL, 0, &new_fd);
361 if (ret <= 0)
362 goto out;
363 peer_name = remote_name(new_fd);
364 PARA_INFO_LOG("got connection from %s, forking\n", peer_name);
365 mmd->num_connects++;
366 mmd->active_connections++;
367 /*
368 * The chunk table is a pointer located in the mmd struct that points
369 * to dynamically allocated memory, i.e. it must be freed by the parent
370 * and the child. However, as the mmd struct is in a shared memory
371 * area, there's no guarantee that after the fork this pointer is still
372 * valid in child context. As it is not used in the child anyway, we
373 * save it to a local variable before the fork and free the memory via
374 * that copy in the child directly after the fork.
375 */
376 chunk_table = mmd->afd.afhi.chunk_table;
377 child_pid = fork();
378 if (child_pid < 0) {
379 ret = -ERRNO_TO_PARA_ERROR(errno);
380 goto out;
381 }
382 if (child_pid) {
383 /* avoid problems with non-fork-safe PRNGs */
384 unsigned char buf[16];
385 get_random_bytes_or_die(buf, sizeof(buf));
386 close(new_fd);
387 /* parent keeps accepting connections */
388 return 0;
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 handle_connect(new_fd, peer_name);
403 /* never reached*/
404 out:
405 if (ret < 0)
406 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
407 return 0;
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->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 sct->task = task_register(&(struct task_info) {
428 .name = "server command",
429 .pre_select = command_pre_select,
430 .post_select = command_post_select,
431 .context = sct,
432 }, &sched);
433 return;
434 err:
435 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
436 exit(EXIT_FAILURE);
437 }
438
439 static int init_afs(int argc, char **argv)
440 {
441 int ret, afs_server_socket[2];
442 pid_t afs_pid;
443
444 ret = socketpair(PF_UNIX, SOCK_DGRAM, 0, afs_server_socket);
445 if (ret < 0)
446 exit(EXIT_FAILURE);
447 get_random_bytes_or_die((unsigned char *)&afs_socket_cookie,
448 sizeof(afs_socket_cookie));
449 afs_pid = fork();
450 if (afs_pid < 0)
451 exit(EXIT_FAILURE);
452 if (afs_pid == 0) { /* child (afs) */
453 int i;
454 for (i = argc - 1; i >= 0; i--)
455 memset(argv[i], 0, strlen(argv[i]));
456 sprintf(argv[0], "para_server (afs)");
457 close(afs_server_socket[0]);
458 afs_init(afs_socket_cookie, afs_server_socket[1]);
459 }
460 mmd->afs_pid = afs_pid;
461 close(afs_server_socket[1]);
462 ret = mark_fd_nonblocking(afs_server_socket[0]);
463 if (ret < 0)
464 exit(EXIT_FAILURE);
465 add_close_on_fork_list(afs_server_socket[0]);
466 PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
467 afs_server_socket[0], (unsigned) afs_socket_cookie);
468 return afs_server_socket[0];
469 }
470
471 __noreturn static void print_help_and_die(void)
472 {
473 struct ggo_help h = DEFINE_GGO_HELP(server);
474 bool d = conf.detailed_help_given;
475
476 ggo_print_help(&h, d? GPH_STANDARD_FLAGS_DETAILED : GPH_STANDARD_FLAGS);
477 exit(0);
478 }
479
480 static void server_init(int argc, char **argv)
481 {
482 struct server_cmdline_parser_params params = {
483 .override = 0,
484 .initialize = 1,
485 .check_required = 0,
486 .check_ambiguity = 0,
487 .print_errors = 1
488 };
489 int afs_socket;
490
491 valid_fd_012();
492 init_random_seed_or_die();
493 /* parse command line options */
494 server_cmdline_parser_ext(argc, argv, &conf, &params);
495 daemon_set_loglevel(conf.loglevel_arg);
496 version_handle_flag("server", conf.version_given);
497 if (conf.help_given || conf.detailed_help_given)
498 print_help_and_die();
499 daemon_drop_privileges_or_die(conf.user_arg, conf.group_arg);
500 /* parse config file, open log and set defaults */
501 parse_config_or_die(0);
502 daemon_log_welcome("para_server");
503 init_ipc_or_die(); /* init mmd struct and mmd->lock */
504 daemon_set_start_time();
505 init_user_list(user_list_file);
506 /* become daemon */
507 if (conf.daemon_given)
508 daemonize(true /* parent waits for SIGTERM */);
509 PARA_NOTICE_LOG("initializing audio format handlers\n");
510 afh_init();
511
512 /*
513 * Although afs uses its own signal handling we must ignore SIGUSR1
514 * _before_ the afs child process gets born by init_afs() below. It's
515 * racy to do this in the child because the parent might send SIGUSR1
516 * before the child gets a chance to ignore this signal -- only the
517 * good die young.
518 */
519 para_sigaction(SIGUSR1, SIG_IGN);
520 /*
521 * We have to block SIGCHLD before the afs process is being forked off.
522 * Otherwise, para_server does not notice if afs dies before the
523 * SIGCHLD handler has been installed for the parent process by
524 * init_signal_task() below.
525 */
526 para_block_signal(SIGCHLD);
527 PARA_NOTICE_LOG("initializing the audio file selector\n");
528 afs_socket = init_afs(argc, argv);
529 init_signal_task();
530 para_unblock_signal(SIGCHLD);
531 PARA_NOTICE_LOG("initializing virtual streaming system\n");
532 init_vss_task(afs_socket, &sched);
533 init_server_command_task(argc, argv);
534 if (conf.daemon_given)
535 kill(getppid(), SIGTERM);
536 PARA_NOTICE_LOG("server init complete\n");
537 }
538
539 static void status_refresh(void)
540 {
541 static int prev_uptime = -1, prev_events = -1;
542 int uptime = daemon_get_uptime(now);
543
544 if (prev_events != mmd->events)
545 goto out;
546 if (mmd->new_vss_status_flags != mmd->vss_status_flags)
547 goto out_inc_events;
548 if (uptime / 60 != prev_uptime / 60)
549 goto out_inc_events;
550 return;
551 out_inc_events:
552 mmd->events++;
553 out:
554 prev_uptime = uptime;
555 prev_events = mmd->events;
556 mmd->vss_status_flags = mmd->new_vss_status_flags;
557 PARA_DEBUG_LOG("%d events, forcing status update\n", mmd->events);
558 killpg(0, SIGUSR1);
559 }
560
561 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
562 struct timeval *timeout_tv)
563 {
564 int ret;
565
566 status_refresh();
567 mutex_unlock(mmd_mutex);
568 ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
569 mutex_lock(mmd_mutex);
570 return ret;
571 }
572
573 /**
574 * The main function of para_server.
575 *
576 * \param argc Usual argument count.
577 * \param argv Usual argument vector.
578 *
579 * \return EXIT_SUCCESS or EXIT_FAILURE.
580 */
581 int main(int argc, char *argv[])
582 {
583 int ret;
584
585 sched.default_timeout.tv_sec = 1;
586 sched.select_function = server_select;
587
588 server_init(argc, argv);
589 mutex_lock(mmd_mutex);
590 ret = schedule(&sched);
591 sched_shutdown(&sched);
592 if (ret < 0) {
593 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
594 exit(EXIT_FAILURE);
595 }
596 exit(EXIT_SUCCESS);
597 }