server: Move afs_pid out of mmd struct.
[paraslash.git] / server.c
1 /* Copyright (C) 1997 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
2
3 /** \file server.c Paraslash's main server. */
4
5 /**
6 * \mainpage Main data structures and selected APIs:
7 *
8 * - Senders: \ref sender,
9 * - Audio file selector: \ref afs_info, \ref afs_table,
10 * - Audio format handler: \ref audio_format_handler, \ref afh_info
11 * - Receivers/filters/writers: \ref receiver, \ref receiver_node,
12 * \ref filter, \ref filter_node, \ref writer_node, \ref writer.
13 * - Scheduling: \ref sched.h,
14 * - Buffer trees: \ref buffer_tree.h,
15 * - Sideband API: \ref sideband.h,
16 * - Crypto: \ref crypt.h, \ref crypt_backend.h,
17 * - Error subsystem: \ref error.h,
18 * - Inter process communication: \ref ipc.h,
19 * - Forward error correction: \ref fec.h,
20 * - Daemons: \ref daemon.h,
21 * - Mixer API: \ref mix.h,
22 * - Interactive sessions: \ref interactive.h,
23 * - File descriptors: \ref fd.h,
24 * - Signals: \ref signal.h,
25 * - Networking: \ref net.h,
26 * - Time: \ref time.c,
27 * - Doubly linked lists: \ref list.h.
28 */
29
30 #include <netinet/in.h>
31 #include <sys/socket.h>
32 #include <signal.h>
33 #include <regex.h>
34 #include <osl.h>
35 #include <sys/types.h>
36 #include <arpa/inet.h>
37 #include <sys/un.h>
38 #include <netdb.h>
39 #include <lopsub.h>
40
41 #include "server.lsg.h"
42 #include "para.h"
43 #include "error.h"
44 #include "crypt.h"
45 #include "afh.h"
46 #include "string.h"
47 #include "afs.h"
48 #include "server.h"
49 #include "list.h"
50 #include "send.h"
51 #include "sched.h"
52 #include "vss.h"
53 #include "config.h"
54 #include "close_on_fork.h"
55 #include "net.h"
56 #include "daemon.h"
57 #include "ipc.h"
58 #include "fd.h"
59 #include "signal.h"
60 #include "user_list.h"
61 #include "color.h"
62 #include "version.h"
63
64 /** Array of error strings. */
65 DEFINE_PARA_ERRLIST;
66
67 __printf_2_3 void (*para_log)(int, const char*, ...) = daemon_log;
68
69 /** Shut down non-authorized connections after that many seconds. */
70 #define ALARM_TIMEOUT 10
71
72 /**
73 * Pointer to shared memory area for communication between para_server
74 * and its children. Exported to vss.c, command.c and to afs.
75 */
76 struct misc_meta_data *mmd;
77
78 /**
79 * The active value for all config options of para_server.
80 *
81 * It is computed by merging the parse result of the command line options with
82 * the parse result of the config file.
83 */
84 struct lls_parse_result *server_lpr = NULL;
85
86 /* Command line options (no config file options). Used in handle_sighup(). */
87 static struct lls_parse_result *cmdline_lpr;
88
89 /** A random value used in child context for authentication. */
90 uint32_t afs_socket_cookie;
91
92 /** The mutex protecting the shared memory area containing the mmd struct. */
93 int mmd_mutex;
94
95 static struct sched sched;
96 static struct signal_task *signal_task;
97
98 /** The process id of the audio file selector process. */
99 pid_t afs_pid = 0;
100
101 /** The task responsible for server command handling. */
102 struct server_command_task {
103 /** TCP port on which para_server listens for connections. */
104 int listen_fd;
105 /** Copied from para_server's main function. */
106 int argc;
107 /** Argument vector passed to para_server's main function. */
108 char **argv;
109 /** The command task structure for scheduling. */
110 struct task *task;
111 };
112
113 /**
114 * Return the list of tasks for the server process.
115 *
116 * This is called from \a com_tasks(). The helper is necessary since command
117 * handlers can not access the scheduler structure directly.
118 *
119 * \return A dynamically allocated string that must be freed by the caller.
120 */
121 char *server_get_tasks(void)
122 {
123 return get_task_list(&sched);
124 }
125
126 /*
127 * setup shared memory area and get mutex for locking
128 */
129 static void init_ipc_or_die(void)
130 {
131 void *shm;
132 int shmid, ret = shm_new(sizeof(struct misc_meta_data));
133
134 if (ret < 0)
135 goto err_out;
136 shmid = ret;
137 ret = shm_attach(shmid, ATTACH_RW, &shm);
138 shm_destroy(shmid);
139 if (ret < 0)
140 goto err_out;
141 mmd = shm;
142
143 ret = mutex_new();
144 if (ret < 0)
145 goto err_out;
146 mmd_mutex = ret;
147
148 mmd->num_played = 0;
149 mmd->num_commands = 0;
150 mmd->events = 0;
151 mmd->num_connects = 0;
152 mmd->active_connections = 0;
153 mmd->vss_status_flags = VSS_NEXT;
154 mmd->new_vss_status_flags = VSS_NEXT;
155 return;
156 err_out:
157 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
158 exit(EXIT_FAILURE);
159 }
160
161 /**
162 * (Re-)read the server configuration files.
163 *
164 * \param reload Whether config file overrides command line.
165 *
166 * This function also re-opens the logfile and the user list. On SIGHUP it is
167 * called from both server and afs context.
168 */
169 void parse_config_or_die(bool reload)
170 {
171 int ret;
172 char *cf = NULL, *errctx = NULL, *user_list_file = NULL;
173 void *map;
174 size_t sz;
175 int cf_argc;
176 char **cf_argv;
177 struct lls_parse_result *cf_lpr, *merged_lpr;
178 char *home = para_homedir();
179
180 daemon_close_log();
181 if (OPT_GIVEN(CONFIG_FILE))
182 cf = para_strdup(OPT_STRING_VAL(CONFIG_FILE));
183 else
184 cf = make_message("%s/.paraslash/server.conf", home);
185 if (!mmd || getpid() != afs_pid) {
186 if (OPT_GIVEN(USER_LIST))
187 user_list_file = para_strdup(OPT_STRING_VAL(USER_LIST));
188 else
189 user_list_file = make_message("%s/.paraslash/server.users", home);
190 }
191 free(home);
192 ret = mmap_full_file(cf, O_RDONLY, &map, &sz, NULL);
193 if (ret < 0) {
194 if (ret != -E_EMPTY && ret != -ERRNO_TO_PARA_ERROR(ENOENT))
195 goto free_cf;
196 if (ret == -ERRNO_TO_PARA_ERROR(ENOENT) && OPT_GIVEN(CONFIG_FILE))
197 goto free_cf;
198 server_lpr = cmdline_lpr;
199 goto success;
200 }
201 ret = lls(lls_convert_config(map, sz, NULL, &cf_argv, &errctx));
202 para_munmap(map, sz);
203 if (ret < 0)
204 goto free_cf;
205 cf_argc = ret;
206 ret = lls(lls_parse(cf_argc, cf_argv, CMD_PTR, &cf_lpr, &errctx));
207 lls_free_argv(cf_argv);
208 if (ret < 0)
209 goto free_cf;
210 if (reload) /* config file overrides command line */
211 ret = lls(lls_merge(cf_lpr, cmdline_lpr, CMD_PTR, &merged_lpr,
212 &errctx));
213 else /* command line options override config file options */
214 ret = lls(lls_merge(cmdline_lpr, cf_lpr, CMD_PTR, &merged_lpr,
215 &errctx));
216 lls_free_parse_result(cf_lpr, CMD_PTR);
217 if (ret < 0)
218 goto free_cf;
219 if (server_lpr != cmdline_lpr)
220 lls_free_parse_result(server_lpr, CMD_PTR);
221 server_lpr = merged_lpr;
222 success:
223 daemon_set_loglevel(ENUM_STRING_VAL(LOGLEVEL));
224 if (OPT_GIVEN(LOGFILE)) {
225 daemon_set_logfile(OPT_STRING_VAL(LOGFILE));
226 daemon_open_log_or_die();
227 }
228 if (daemon_init_colors_or_die(OPT_UINT32_VAL(COLOR), COLOR_AUTO,
229 COLOR_NO, OPT_GIVEN(LOGFILE))) {
230 int i;
231 for (i = 0; i < OPT_GIVEN(LOG_COLOR); i++)
232 daemon_set_log_color_or_die(lls_string_val(i,
233 OPT_RESULT(LOG_COLOR)));
234 }
235 daemon_set_flag(DF_LOG_PID);
236 daemon_set_flag(DF_LOG_LL);
237 daemon_set_flag(DF_LOG_TIME);
238 if (OPT_GIVEN(LOG_TIMING))
239 daemon_set_flag(DF_LOG_TIMING);
240 daemon_set_priority(OPT_UINT32_VAL(PRIORITY));
241 if (user_list_file)
242 init_user_list(user_list_file);
243 ret = 1;
244 free_cf:
245 free(cf);
246 free(user_list_file);
247 if (ret < 0) {
248 if (errctx)
249 PARA_ERROR_LOG("%s\n", errctx);
250 free(errctx);
251 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
252 exit(EXIT_FAILURE);
253 }
254 }
255
256 /*
257 * called when server gets SIGHUP or when client invokes hup command.
258 */
259 static void handle_sighup(void)
260 {
261
262 PARA_NOTICE_LOG("SIGHUP\n");
263 parse_config_or_die(true);
264 if (afs_pid != 0)
265 kill(afs_pid, SIGHUP);
266 }
267
268 static int signal_post_select(struct sched *s, __a_unused void *context)
269 {
270 int signum = para_next_signal(&s->rfds);
271
272 switch (signum) {
273 case 0:
274 return 0;
275 case SIGHUP:
276 handle_sighup();
277 break;
278 case SIGCHLD:
279 for (;;) {
280 pid_t pid;
281 int ret = para_reap_child(&pid);
282 if (ret <= 0)
283 break;
284 if (pid != afs_pid)
285 continue;
286 PARA_EMERG_LOG("fatal: afs died\n");
287 kill(0, SIGTERM);
288 goto cleanup;
289 }
290 break;
291 /* die on sigint/sigterm. Kill all children too. */
292 case SIGINT:
293 case SIGTERM:
294 PARA_EMERG_LOG("terminating on signal %d\n", signum);
295 kill(0, SIGTERM);
296 /*
297 * We must wait for afs because afs catches SIGINT/SIGTERM.
298 * Before reacting to the signal, afs might want to use the
299 * shared memory area and the mmd mutex. If we destroy this
300 * mutex too early and afs tries to lock the shared memory
301 * area, the call to mutex_lock() will fail and terminate the
302 * afs process. This leads to dirty osl tables.
303 *
304 * There's no such problem with the other children of the
305 * server process (the command handlers) as these reset their
306 * SIGINT/SIGTERM handlers to the default action, i.e. these
307 * processes get killed immediately by the above kill().
308 */
309 PARA_INFO_LOG("waiting for afs (pid %d) to die\n",
310 (int)afs_pid);
311 waitpid(afs_pid, NULL, 0);
312 cleanup:
313 free(mmd->afd.afhi.chunk_table);
314 close_listed_fds();
315 mutex_destroy(mmd_mutex);
316 shm_detach(mmd);
317 exit(EXIT_FAILURE);
318 }
319 return 0;
320 }
321
322 static void init_signal_task(void)
323 {
324 signal_task = signal_init_or_die();
325 para_install_sighandler(SIGINT);
326 para_install_sighandler(SIGTERM);
327 para_install_sighandler(SIGHUP);
328 para_install_sighandler(SIGCHLD);
329 para_sigaction(SIGPIPE, SIG_IGN);
330 add_close_on_fork_list(signal_task->fd);
331 signal_task->task = task_register(&(struct task_info) {
332 .name = "signal",
333 .pre_select = signal_pre_select,
334 .post_select = signal_post_select,
335 .context = signal_task,
336
337 }, &sched);
338 }
339
340 static void command_pre_select(struct sched *s, void *context)
341 {
342 struct server_command_task *sct = context;
343 para_fd_set(sct->listen_fd, &s->rfds, &s->max_fileno);
344 }
345
346 static int command_post_select(struct sched *s, void *context)
347 {
348 struct server_command_task *sct = context;
349
350 int new_fd, ret, i;
351 char *peer_name;
352 pid_t child_pid;
353 uint32_t *chunk_table;
354
355 ret = para_accept(sct->listen_fd, &s->rfds, NULL, 0, &new_fd);
356 if (ret <= 0)
357 goto out;
358 mmd->num_connects++;
359 mmd->active_connections++;
360 /*
361 * The chunk table is a pointer located in the mmd struct that points
362 * to dynamically allocated memory, i.e. it must be freed by the parent
363 * and the child. However, as the mmd struct is in a shared memory
364 * area, there's no guarantee that after the fork this pointer is still
365 * valid in child context. As it is not used in the child anyway, we
366 * save it to a local variable before the fork and free the memory via
367 * that copy in the child directly after the fork.
368 */
369 chunk_table = mmd->afd.afhi.chunk_table;
370 child_pid = fork();
371 if (child_pid < 0) {
372 ret = -ERRNO_TO_PARA_ERROR(errno);
373 goto out;
374 }
375 if (child_pid) {
376 /* avoid problems with non-fork-safe PRNGs */
377 unsigned char buf[16];
378 get_random_bytes_or_die(buf, sizeof(buf));
379 close(new_fd);
380 /* parent keeps accepting connections */
381 return 0;
382 }
383 peer_name = remote_name(new_fd);
384 PARA_INFO_LOG("accepted connection from %s\n", peer_name);
385 /* mmd might already have changed at this point */
386 free(chunk_table);
387 alarm(ALARM_TIMEOUT);
388 close_listed_fds();
389 signal_shutdown(signal_task);
390 /*
391 * put info on who we are serving into argv[0] to make
392 * client ip visible in top/ps
393 */
394 for (i = sct->argc - 1; i >= 0; i--)
395 memset(sct->argv[i], 0, strlen(sct->argv[i]));
396 i = sct->argc - 1 - lls_num_inputs(cmdline_lpr);
397 sprintf(sct->argv[i], "para_server (serving %s)", peer_name);
398 handle_connect(new_fd);
399 /* never reached*/
400 out:
401 if (ret < 0)
402 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
403 return 0;
404 }
405
406 static void init_server_command_task(int argc, char **argv)
407 {
408 int ret;
409 static struct server_command_task server_command_task_struct,
410 *sct = &server_command_task_struct;
411
412 PARA_NOTICE_LOG("initializing tcp command socket\n");
413 sct->argc = argc;
414 sct->argv = argv;
415 ret = para_listen_simple(IPPROTO_TCP, OPT_UINT32_VAL(PORT));
416 if (ret < 0)
417 goto err;
418 sct->listen_fd = ret;
419 ret = mark_fd_nonblocking(sct->listen_fd);
420 if (ret < 0)
421 goto err;
422 add_close_on_fork_list(sct->listen_fd); /* child doesn't need the listener */
423 sct->task = task_register(&(struct task_info) {
424 .name = "server command",
425 .pre_select = command_pre_select,
426 .post_select = command_post_select,
427 .context = sct,
428 }, &sched);
429 return;
430 err:
431 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
432 exit(EXIT_FAILURE);
433 }
434
435 static int init_afs(int argc, char **argv)
436 {
437 int ret, afs_server_socket[2];
438 char c;
439
440 ret = socketpair(PF_UNIX, SOCK_STREAM, 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 int i;
450
451 afs_pid = getpid();
452 for (i = argc - 1; i >= 0; i--)
453 memset(argv[i], 0, strlen(argv[i]));
454 i = argc - lls_num_inputs(cmdline_lpr) - 1;
455 sprintf(argv[i], "para_server (afs)");
456 close(afs_server_socket[0]);
457 afs_init(afs_socket_cookie, afs_server_socket[1]);
458 }
459 close(afs_server_socket[1]);
460 if (read(afs_server_socket[0], &c, 1) <= 0) {
461 PARA_EMERG_LOG("early afs exit\n");
462 exit(EXIT_FAILURE);
463 }
464 ret = mark_fd_nonblocking(afs_server_socket[0]);
465 if (ret < 0)
466 exit(EXIT_FAILURE);
467 add_close_on_fork_list(afs_server_socket[0]);
468 PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
469 afs_server_socket[0], (unsigned) afs_socket_cookie);
470 return afs_server_socket[0];
471 }
472
473 static void handle_help_flags(void)
474 {
475 char *help;
476 bool d = OPT_GIVEN(DETAILED_HELP);
477
478 if (d)
479 help = lls_long_help(CMD_PTR);
480 else if (OPT_GIVEN(HELP))
481 help = lls_short_help(CMD_PTR);
482 else
483 return;
484 printf("%s\n", help);
485 free(help);
486 exit(EXIT_SUCCESS);
487 }
488
489 static void server_init(int argc, char **argv)
490 {
491 int ret, afs_socket, daemon_pipe = -1;
492 char *errctx;
493
494 valid_fd_012();
495 /* parse command line options */
496 ret = lls(lls_parse(argc, argv, CMD_PTR, &cmdline_lpr, &errctx));
497 if (ret < 0)
498 goto fail;
499 server_lpr = cmdline_lpr;
500 daemon_set_loglevel(ENUM_STRING_VAL(LOGLEVEL));
501 daemon_drop_privileges_or_die(OPT_STRING_VAL(USER),
502 OPT_STRING_VAL(GROUP));
503 version_handle_flag("server", OPT_GIVEN(VERSION));
504 handle_help_flags();
505 parse_config_or_die(false);
506 /* become daemon */
507 if (OPT_GIVEN(DAEMON))
508 daemon_pipe = daemonize(true /* parent waits for SIGTERM */);
509 init_random_seed_or_die();
510 daemon_log_welcome("server");
511 init_ipc_or_die(); /* init mmd struct and mmd->lock */
512 daemon_set_start_time();
513 PARA_NOTICE_LOG("initializing audio format handlers\n");
514 afh_init();
515
516 /*
517 * Although afs uses its own signal handling we must ignore SIGUSR1
518 * _before_ the afs child process gets born by init_afs() below. It's
519 * racy to do this in the child because the parent might send SIGUSR1
520 * before the child gets a chance to ignore this signal.
521 *
522 * We also have to block SIGCHLD before the afs process is created
523 * because otherwise para_server does not notice if afs dies before the
524 * SIGCHLD handler has been installed for the parent process by
525 * init_signal_task() below.
526 */
527 para_sigaction(SIGUSR1, SIG_IGN);
528 para_block_signal(SIGCHLD);
529 PARA_NOTICE_LOG("initializing the audio file selector\n");
530 afs_socket = init_afs(argc, argv);
531 init_signal_task();
532 para_unblock_signal(SIGCHLD);
533 PARA_NOTICE_LOG("initializing virtual streaming system\n");
534 vss_init(afs_socket, &sched);
535 init_server_command_task(argc, argv);
536 if (daemon_pipe >= 0) {
537 if (write(daemon_pipe, "\0", 1) < 0) {
538 PARA_EMERG_LOG("daemon_pipe: %s", strerror(errno));
539 exit(EXIT_FAILURE);
540 }
541 close(daemon_pipe);
542 }
543 PARA_NOTICE_LOG("server init complete\n");
544 return;
545 fail:
546 assert(ret < 0);
547 if (errctx)
548 PARA_ERROR_LOG("%s\n", errctx);
549 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
550 exit(EXIT_FAILURE);
551 }
552
553 static void status_refresh(void)
554 {
555 static int prev_uptime = -1, prev_events = -1;
556 int uptime = daemon_get_uptime(now);
557
558 if (prev_events != mmd->events)
559 goto out;
560 if (mmd->new_vss_status_flags != mmd->vss_status_flags)
561 goto out_inc_events;
562 if (uptime / 60 != prev_uptime / 60)
563 goto out_inc_events;
564 return;
565 out_inc_events:
566 mmd->events++;
567 out:
568 prev_uptime = uptime;
569 prev_events = mmd->events;
570 mmd->vss_status_flags = mmd->new_vss_status_flags;
571 PARA_DEBUG_LOG("%u events, forcing status update\n", mmd->events);
572 killpg(0, SIGUSR1);
573 }
574
575 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
576 struct timeval *timeout_tv)
577 {
578 int ret;
579
580 status_refresh();
581 mutex_unlock(mmd_mutex);
582 ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
583 mutex_lock(mmd_mutex);
584 return ret;
585 }
586
587 /**
588 * The main function of para_server.
589 *
590 * \param argc Usual argument count.
591 * \param argv Usual argument vector.
592 *
593 * \return EXIT_SUCCESS or EXIT_FAILURE.
594 */
595 int main(int argc, char *argv[])
596 {
597 int ret;
598
599 sched.default_timeout.tv_sec = 1;
600 sched.select_function = server_select;
601
602 server_init(argc, argv);
603 mutex_lock(mmd_mutex);
604 ret = schedule(&sched);
605 sched_shutdown(&sched);
606 lls_free_parse_result(server_lpr, CMD_PTR);
607 if (server_lpr != cmdline_lpr)
608 lls_free_parse_result(cmdline_lpr, CMD_PTR);
609 if (ret < 0)
610 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
611 exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);
612 }