server: Get rid of a dead store.
[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 and selected APIs:
11 *
12 * - Senders: \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 * - Scheduling: \ref sched.h,
18 * - Buffer trees: \ref buffer_tree.h,
19 * - Sideband API: \ref sideband.h,
20 * - Crypto: \ref crypt.h, \ref crypt_backend.h,
21 * - Error subsystem: \ref error.h,
22 * - Inter process communication: \ref ipc.h,
23 * - Forward error correction: \ref fec.h,
24 * - Daemons: \ref daemon.h,
25 * - Mixer API: \ref mix.h,
26 * - Interactive sessions: \ref interactive.h,
27 * - File descriptors: \ref fd.h,
28 * - Signals: \ref signal.h,
29 * - Networking: \ref net.h,
30 * - Time: \ref time.c,
31 * - Doubly linked lists: \ref list.h.
32 */
33
34 #include <netinet/in.h>
35 #include <sys/socket.h>
36 #include <signal.h>
37 #include <regex.h>
38 #include <osl.h>
39 #include <sys/types.h>
40 #include <arpa/inet.h>
41 #include <sys/un.h>
42 #include <netdb.h>
43 #include <lopsub.h>
44
45 #include "server.lsg.h"
46 #include "para.h"
47 #include "error.h"
48 #include "crypt.h"
49 #include "afh.h"
50 #include "string.h"
51 #include "afs.h"
52 #include "server.h"
53 #include "list.h"
54 #include "send.h"
55 #include "sched.h"
56 #include "vss.h"
57 #include "config.h"
58 #include "close_on_fork.h"
59 #include "net.h"
60 #include "daemon.h"
61 #include "ipc.h"
62 #include "fd.h"
63 #include "signal.h"
64 #include "user_list.h"
65 #include "color.h"
66 #include "version.h"
67
68 /** Array of error strings. */
69 DEFINE_PARA_ERRLIST;
70
71 __printf_2_3 void (*para_log)(int, const char*, ...) = daemon_log;
72
73 /** Shut down non-authorized connections after that many seconds. */
74 #define ALARM_TIMEOUT 10
75
76 /**
77 * Pointer to shared memory area for communication between para_server
78 * and its children. Exported to vss.c, command.c and to afs.
79 */
80 struct misc_meta_data *mmd;
81
82 /**
83 * The active value for all config options of para_server.
84 *
85 * It is computed by merging the parse result of the command line options with
86 * the parse result of the config file.
87 */
88 struct lls_parse_result *server_lpr = NULL;
89
90 /* Command line options (no config file options). Used in handle_sighup(). */
91 static struct lls_parse_result *cmdline_lpr;
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 static struct sched sched;
100 static struct signal_task *signal_task;
101
102 /** The task responsible for server command handling. */
103 struct server_command_task {
104 /** TCP port on which para_server listens for connections. */
105 int listen_fd;
106 /** Copied from para_server's main function. */
107 int argc;
108 /** Argument vector passed to para_server's main function. */
109 char **argv;
110 /** The command task structure for scheduling. */
111 struct task *task;
112 };
113
114 /**
115 * Return the list of tasks for the server process.
116 *
117 * This is called from \a com_tasks(). The helper is necessary since command
118 * handlers can not access the scheduler structure directly.
119 *
120 * \return A dynamically allocated string that must be freed by the caller.
121 */
122 char *server_get_tasks(void)
123 {
124 return get_task_list(&sched);
125 }
126
127 /*
128 * setup shared memory area and get mutex for locking
129 */
130 static void init_ipc_or_die(void)
131 {
132 void *shm;
133 int shmid, ret = shm_new(sizeof(struct misc_meta_data));
134
135 if (ret < 0)
136 goto err_out;
137 shmid = ret;
138 ret = shm_attach(shmid, ATTACH_RW, &shm);
139 shm_destroy(shmid);
140 if (ret < 0)
141 goto err_out;
142 mmd = shm;
143
144 ret = mutex_new();
145 if (ret < 0)
146 goto err_out;
147 mmd_mutex = ret;
148
149 mmd->num_played = 0;
150 mmd->num_commands = 0;
151 mmd->events = 0;
152 mmd->num_connects = 0;
153 mmd->active_connections = 0;
154 mmd->vss_status_flags = VSS_NEXT;
155 mmd->new_vss_status_flags = VSS_NEXT;
156 return;
157 err_out:
158 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
159 exit(EXIT_FAILURE);
160 }
161
162 /**
163 * (Re-)read the server configuration files.
164 *
165 * \param reload Whether config file overrides command line.
166 *
167 * This function also re-opens the logfile and the user list. On SIGHUP it is
168 * called from both server and afs context.
169 */
170 void parse_config_or_die(bool reload)
171 {
172 int ret;
173 char *cf = NULL, *errctx = NULL, *user_list_file = NULL;
174 void *map;
175 size_t sz;
176 int cf_argc;
177 char **cf_argv;
178 struct lls_parse_result *cf_lpr, *merged_lpr;
179 char *home = para_homedir();
180
181 daemon_close_log();
182 if (OPT_GIVEN(CONFIG_FILE))
183 cf = para_strdup(OPT_STRING_VAL(CONFIG_FILE));
184 else
185 cf = make_message("%s/.paraslash/server.conf", home);
186 if (!mmd || getpid() != mmd->afs_pid) {
187 if (OPT_GIVEN(USER_LIST))
188 user_list_file = para_strdup(OPT_STRING_VAL(USER_LIST));
189 else
190 user_list_file = make_message("%s/.paraslash/server.users", home);
191 }
192 free(home);
193 ret = mmap_full_file(cf, O_RDONLY, &map, &sz, NULL);
194 if (ret < 0) {
195 if (ret != -E_EMPTY && ret != -ERRNO_TO_PARA_ERROR(ENOENT))
196 goto free_cf;
197 if (ret == -ERRNO_TO_PARA_ERROR(ENOENT) && OPT_GIVEN(CONFIG_FILE))
198 goto free_cf;
199 server_lpr = cmdline_lpr;
200 goto success;
201 }
202 ret = lls(lls_convert_config(map, sz, NULL, &cf_argv, &errctx));
203 para_munmap(map, sz);
204 if (ret < 0)
205 goto free_cf;
206 cf_argc = ret;
207 ret = lls(lls_parse(cf_argc, cf_argv, CMD_PTR, &cf_lpr, &errctx));
208 lls_free_argv(cf_argv);
209 if (ret < 0)
210 goto free_cf;
211 if (reload) /* config file overrides command line */
212 ret = lls(lls_merge(cf_lpr, cmdline_lpr, CMD_PTR, &merged_lpr,
213 &errctx));
214 else /* command line options overrride config file options */
215 ret = lls(lls_merge(cmdline_lpr, cf_lpr, CMD_PTR, &merged_lpr,
216 &errctx));
217 lls_free_parse_result(cf_lpr, CMD_PTR);
218 if (ret < 0)
219 goto free_cf;
220 if (server_lpr != cmdline_lpr)
221 lls_free_parse_result(server_lpr, CMD_PTR);
222 server_lpr = merged_lpr;
223 success:
224 daemon_set_loglevel(ENUM_STRING_VAL(LOGLEVEL));
225 if (OPT_GIVEN(LOGFILE)) {
226 daemon_set_logfile(OPT_STRING_VAL(LOGFILE));
227 daemon_open_log_or_die();
228 }
229 if (daemon_init_colors_or_die(OPT_UINT32_VAL(COLOR), COLOR_AUTO,
230 COLOR_NO, OPT_GIVEN(LOGFILE))) {
231 int i;
232 for (i = 0; i < OPT_GIVEN(LOG_COLOR); i++)
233 daemon_set_log_color_or_die(lls_string_val(i,
234 OPT_RESULT(LOG_COLOR)));
235 }
236 daemon_set_flag(DF_LOG_PID);
237 daemon_set_flag(DF_LOG_LL);
238 daemon_set_flag(DF_LOG_TIME);
239 if (OPT_GIVEN(LOG_TIMING))
240 daemon_set_flag(DF_LOG_TIMING);
241 daemon_set_priority(OPT_UINT32_VAL(PRIORITY));
242 if (user_list_file)
243 init_user_list(user_list_file);
244 ret = 1;
245 free_cf:
246 free(cf);
247 free(user_list_file);
248 if (ret < 0) {
249 if (errctx)
250 PARA_ERROR_LOG("%s\n", errctx);
251 free(errctx);
252 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
253 exit(EXIT_FAILURE);
254 }
255 }
256
257 /*
258 * called when server gets SIGHUP or when client invokes hup command.
259 */
260 static void handle_sighup(void)
261 {
262
263 PARA_NOTICE_LOG("SIGHUP\n");
264 parse_config_or_die(true);
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 signal_task = signal_init_or_die();
326 para_install_sighandler(SIGINT);
327 para_install_sighandler(SIGTERM);
328 para_install_sighandler(SIGHUP);
329 para_install_sighandler(SIGCHLD);
330 para_sigaction(SIGPIPE, SIG_IGN);
331 add_close_on_fork_list(signal_task->fd);
332 signal_task->task = task_register(&(struct task_info) {
333 .name = "signal",
334 .pre_select = signal_pre_select,
335 .post_select = signal_post_select,
336 .context = signal_task,
337
338 }, &sched);
339 }
340
341 static void command_pre_select(struct sched *s, void *context)
342 {
343 struct server_command_task *sct = context;
344 para_fd_set(sct->listen_fd, &s->rfds, &s->max_fileno);
345 }
346
347 static int command_post_select(struct sched *s, void *context)
348 {
349 struct server_command_task *sct = context;
350
351 int new_fd, ret, i;
352 char *peer_name;
353 pid_t child_pid;
354 uint32_t *chunk_table;
355
356 ret = para_accept(sct->listen_fd, &s->rfds, NULL, 0, &new_fd);
357 if (ret <= 0)
358 goto out;
359 mmd->num_connects++;
360 mmd->active_connections++;
361 /*
362 * The chunk table is a pointer located in the mmd struct that points
363 * to dynamically allocated memory, i.e. it must be freed by the parent
364 * and the child. However, as the mmd struct is in a shared memory
365 * area, there's no guarantee that after the fork this pointer is still
366 * valid in child context. As it is not used in the child anyway, we
367 * save it to a local variable before the fork and free the memory via
368 * that copy in the child directly after the fork.
369 */
370 chunk_table = mmd->afd.afhi.chunk_table;
371 child_pid = fork();
372 if (child_pid < 0) {
373 ret = -ERRNO_TO_PARA_ERROR(errno);
374 goto out;
375 }
376 if (child_pid) {
377 /* avoid problems with non-fork-safe PRNGs */
378 unsigned char buf[16];
379 get_random_bytes_or_die(buf, sizeof(buf));
380 close(new_fd);
381 /* parent keeps accepting connections */
382 return 0;
383 }
384 peer_name = remote_name(new_fd);
385 PARA_INFO_LOG("accepted connection from %s\n", peer_name);
386 /* mmd might already have changed at this point */
387 free(chunk_table);
388 alarm(ALARM_TIMEOUT);
389 close_listed_fds();
390 signal_shutdown(signal_task);
391 /*
392 * put info on who we are serving into argv[0] to make
393 * client ip visible in top/ps
394 */
395 for (i = sct->argc - 1; i >= 0; i--)
396 memset(sct->argv[i], 0, strlen(sct->argv[i]));
397 i = sct->argc - 1 - lls_num_inputs(cmdline_lpr);
398 sprintf(sct->argv[i], "para_server (serving %s)", peer_name);
399 handle_connect(new_fd, peer_name);
400 /* never reached*/
401 out:
402 if (ret < 0)
403 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
404 return 0;
405 }
406
407 static void init_server_command_task(int argc, char **argv)
408 {
409 int ret;
410 static struct server_command_task server_command_task_struct,
411 *sct = &server_command_task_struct;
412
413 PARA_NOTICE_LOG("initializing tcp command socket\n");
414 sct->argc = argc;
415 sct->argv = argv;
416 ret = para_listen_simple(IPPROTO_TCP, OPT_UINT32_VAL(PORT));
417 if (ret < 0)
418 goto err;
419 sct->listen_fd = ret;
420 ret = mark_fd_nonblocking(sct->listen_fd);
421 if (ret < 0)
422 goto err;
423 add_close_on_fork_list(sct->listen_fd); /* child doesn't need the listener */
424 sct->task = task_register(&(struct task_info) {
425 .name = "server command",
426 .pre_select = command_pre_select,
427 .post_select = command_post_select,
428 .context = sct,
429 }, &sched);
430 return;
431 err:
432 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
433 exit(EXIT_FAILURE);
434 }
435
436 static int init_afs(int argc, char **argv)
437 {
438 int ret, afs_server_socket[2];
439 pid_t afs_pid;
440 char c;
441
442 ret = socketpair(PF_UNIX, SOCK_STREAM, 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 int i;
452
453 for (i = argc - 1; i >= 0; i--)
454 memset(argv[i], 0, strlen(argv[i]));
455 i = argc - lls_num_inputs(cmdline_lpr) - 1;
456 sprintf(argv[i], "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 if (read(afs_server_socket[0], &c, 1) <= 0) {
463 PARA_EMERG_LOG("early afs exit\n");
464 exit(EXIT_FAILURE);
465 }
466 ret = mark_fd_nonblocking(afs_server_socket[0]);
467 if (ret < 0)
468 exit(EXIT_FAILURE);
469 add_close_on_fork_list(afs_server_socket[0]);
470 PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
471 afs_server_socket[0], (unsigned) afs_socket_cookie);
472 return afs_server_socket[0];
473 }
474
475 static void handle_help_flags(void)
476 {
477 char *help;
478 bool d = OPT_GIVEN(DETAILED_HELP);
479
480 if (d)
481 help = lls_long_help(CMD_PTR);
482 else if (OPT_GIVEN(HELP))
483 help = lls_short_help(CMD_PTR);
484 else
485 return;
486 printf("%s\n", help);
487 free(help);
488 exit(EXIT_SUCCESS);
489 }
490
491 static void server_init(int argc, char **argv)
492 {
493 int ret, afs_socket, daemon_pipe = -1;
494 char *errctx;
495
496 valid_fd_012();
497 /* parse command line options */
498 ret = lls(lls_parse(argc, argv, CMD_PTR, &cmdline_lpr, &errctx));
499 if (ret < 0)
500 goto fail;
501 server_lpr = cmdline_lpr;
502 daemon_set_loglevel(ENUM_STRING_VAL(LOGLEVEL));
503 daemon_drop_privileges_or_die(OPT_STRING_VAL(USER),
504 OPT_STRING_VAL(GROUP));
505 version_handle_flag("server", OPT_GIVEN(VERSION));
506 handle_help_flags();
507 parse_config_or_die(false);
508 /* become daemon */
509 if (OPT_GIVEN(DAEMON))
510 daemon_pipe = daemonize(true /* parent waits for SIGTERM */);
511 init_random_seed_or_die();
512 daemon_log_welcome("server");
513 init_ipc_or_die(); /* init mmd struct and mmd->lock */
514 daemon_set_start_time();
515 PARA_NOTICE_LOG("initializing audio format handlers\n");
516 afh_init();
517
518 /*
519 * Although afs uses its own signal handling we must ignore SIGUSR1
520 * _before_ the afs child process gets born by init_afs() below. It's
521 * racy to do this in the child because the parent might send SIGUSR1
522 * before the child gets a chance to ignore this signal.
523 *
524 * We also have to block SIGCHLD before the afs process is created
525 * because otherwise para_server does not notice if afs dies before the
526 * SIGCHLD handler has been installed for the parent process by
527 * init_signal_task() below.
528 */
529 para_sigaction(SIGUSR1, SIG_IGN);
530 para_block_signal(SIGCHLD);
531 PARA_NOTICE_LOG("initializing the audio file selector\n");
532 afs_socket = init_afs(argc, argv);
533 init_signal_task();
534 para_unblock_signal(SIGCHLD);
535 PARA_NOTICE_LOG("initializing virtual streaming system\n");
536 vss_init(afs_socket, &sched);
537 init_server_command_task(argc, argv);
538 if (daemon_pipe >= 0) {
539 if (write(daemon_pipe, "\0", 1) < 0) {
540 PARA_EMERG_LOG("daemon_pipe: %s", strerror(errno));
541 exit(EXIT_FAILURE);
542 }
543 close(daemon_pipe);
544 }
545 PARA_NOTICE_LOG("server init complete\n");
546 return;
547 fail:
548 assert(ret < 0);
549 if (errctx)
550 PARA_ERROR_LOG("%s\n", errctx);
551 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
552 exit(EXIT_FAILURE);
553 }
554
555 static void status_refresh(void)
556 {
557 static int prev_uptime = -1, prev_events = -1;
558 int uptime = daemon_get_uptime(now);
559
560 if (prev_events != mmd->events)
561 goto out;
562 if (mmd->new_vss_status_flags != mmd->vss_status_flags)
563 goto out_inc_events;
564 if (uptime / 60 != prev_uptime / 60)
565 goto out_inc_events;
566 return;
567 out_inc_events:
568 mmd->events++;
569 out:
570 prev_uptime = uptime;
571 prev_events = mmd->events;
572 mmd->vss_status_flags = mmd->new_vss_status_flags;
573 PARA_DEBUG_LOG("%u events, forcing status update\n", mmd->events);
574 killpg(0, SIGUSR1);
575 }
576
577 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
578 struct timeval *timeout_tv)
579 {
580 int ret;
581
582 status_refresh();
583 mutex_unlock(mmd_mutex);
584 ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
585 mutex_lock(mmd_mutex);
586 return ret;
587 }
588
589 /**
590 * The main function of para_server.
591 *
592 * \param argc Usual argument count.
593 * \param argv Usual argument vector.
594 *
595 * \return EXIT_SUCCESS or EXIT_FAILURE.
596 */
597 int main(int argc, char *argv[])
598 {
599 int ret;
600
601 sched.default_timeout.tv_sec = 1;
602 sched.select_function = server_select;
603
604 server_init(argc, argv);
605 mutex_lock(mmd_mutex);
606 ret = schedule(&sched);
607 sched_shutdown(&sched);
608 lls_free_parse_result(server_lpr, CMD_PTR);
609 if (server_lpr != cmdline_lpr)
610 lls_free_parse_result(cmdline_lpr, CMD_PTR);
611 if (ret < 0)
612 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
613 exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);
614 }