8c2a78f4a62ed4fd32a0a95174aa03bb88178ec7
[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 /**
90 * A random number used to "authenticate" the afs connection.
91 *
92 * para_server picks this number by random before it forks the afs process. The
93 * command handlers know this number as well and write it to the afs socket,
94 * together with the id of the shared memory area which contains the payload of
95 * the afs command. A local process has to know this number to abuse the afs
96 * service provided by the local socket.
97 */
98 uint32_t afs_socket_cookie;
99
100 /** The mutex protecting the shared memory area containing the mmd struct. */
101 int mmd_mutex;
102
103 static struct sched sched;
104 static struct signal_task *signal_task;
105
106 /** The process id of the audio file selector process. */
107 pid_t afs_pid = 0;
108
109 /** The task responsible for server command handling. */
110 struct server_command_task {
111 /** TCP port on which para_server listens for connections. */
112 int listen_fd;
113 /** Copied from para_server's main function. */
114 int argc;
115 /** Argument vector passed to para_server's main function. */
116 char **argv;
117 /** The command task structure for scheduling. */
118 struct task *task;
119 };
120
121 /**
122 * Return the list of tasks for the server process.
123 *
124 * This is called from \a com_tasks(). The helper is necessary since command
125 * handlers can not access the scheduler structure directly.
126 *
127 * \return A dynamically allocated string that must be freed by the caller.
128 */
129 char *server_get_tasks(void)
130 {
131 return get_task_list(&sched);
132 }
133
134 /*
135 * setup shared memory area and get mutex for locking
136 */
137 static void init_ipc_or_die(void)
138 {
139 void *shm;
140 int shmid, ret = shm_new(sizeof(struct misc_meta_data));
141
142 if (ret < 0)
143 goto err_out;
144 shmid = ret;
145 ret = shm_attach(shmid, ATTACH_RW, &shm);
146 shm_destroy(shmid);
147 if (ret < 0)
148 goto err_out;
149 mmd = shm;
150
151 ret = mutex_new();
152 if (ret < 0)
153 goto err_out;
154 mmd_mutex = ret;
155
156 mmd->num_played = 0;
157 mmd->num_commands = 0;
158 mmd->events = 0;
159 mmd->num_connects = 0;
160 mmd->active_connections = 0;
161 mmd->vss_status_flags = VSS_NEXT;
162 mmd->new_vss_status_flags = VSS_NEXT;
163 return;
164 err_out:
165 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
166 exit(EXIT_FAILURE);
167 }
168
169 /**
170 * (Re-)read the server configuration files.
171 *
172 * \param reload Whether config file overrides command line.
173 *
174 * This function also re-opens the logfile and the user list. On SIGHUP it is
175 * called from both server and afs context.
176 */
177 void parse_config_or_die(bool reload)
178 {
179 int ret;
180 char *cf = NULL, *errctx = NULL, *user_list_file = NULL;
181 void *map;
182 size_t sz;
183 int cf_argc;
184 char **cf_argv;
185 struct lls_parse_result *cf_lpr, *merged_lpr;
186 char *home = para_homedir();
187
188 daemon_close_log();
189 if (OPT_GIVEN(CONFIG_FILE))
190 cf = para_strdup(OPT_STRING_VAL(CONFIG_FILE));
191 else
192 cf = make_message("%s/.paraslash/server.conf", home);
193 if (!mmd || getpid() != afs_pid) {
194 if (OPT_GIVEN(USER_LIST))
195 user_list_file = para_strdup(OPT_STRING_VAL(USER_LIST));
196 else
197 user_list_file = make_message("%s/.paraslash/server.users", home);
198 }
199 free(home);
200 ret = mmap_full_file(cf, O_RDONLY, &map, &sz, NULL);
201 if (ret < 0) {
202 if (ret != -E_EMPTY && ret != -ERRNO_TO_PARA_ERROR(ENOENT))
203 goto free_cf;
204 if (ret == -ERRNO_TO_PARA_ERROR(ENOENT) && OPT_GIVEN(CONFIG_FILE))
205 goto free_cf;
206 server_lpr = cmdline_lpr;
207 goto success;
208 }
209 ret = lls(lls_convert_config(map, sz, NULL, &cf_argv, &errctx));
210 para_munmap(map, sz);
211 if (ret < 0)
212 goto free_cf;
213 cf_argc = ret;
214 ret = lls(lls_parse(cf_argc, cf_argv, CMD_PTR, &cf_lpr, &errctx));
215 lls_free_argv(cf_argv);
216 if (ret < 0)
217 goto free_cf;
218 if (reload) /* config file overrides command line */
219 ret = lls(lls_merge(cf_lpr, cmdline_lpr, CMD_PTR, &merged_lpr,
220 &errctx));
221 else /* command line options override config file options */
222 ret = lls(lls_merge(cmdline_lpr, cf_lpr, CMD_PTR, &merged_lpr,
223 &errctx));
224 lls_free_parse_result(cf_lpr, CMD_PTR);
225 if (ret < 0)
226 goto free_cf;
227 if (server_lpr != cmdline_lpr)
228 lls_free_parse_result(server_lpr, CMD_PTR);
229 server_lpr = merged_lpr;
230 success:
231 daemon_set_loglevel(ENUM_STRING_VAL(LOGLEVEL));
232 if (OPT_GIVEN(LOGFILE)) {
233 daemon_set_logfile(OPT_STRING_VAL(LOGFILE));
234 daemon_open_log_or_die();
235 }
236 if (daemon_init_colors_or_die(OPT_UINT32_VAL(COLOR), COLOR_AUTO,
237 COLOR_NO, OPT_GIVEN(LOGFILE))) {
238 int i;
239 for (i = 0; i < OPT_GIVEN(LOG_COLOR); i++)
240 daemon_set_log_color_or_die(lls_string_val(i,
241 OPT_RESULT(LOG_COLOR)));
242 }
243 daemon_set_flag(DF_LOG_PID);
244 daemon_set_flag(DF_LOG_LL);
245 daemon_set_flag(DF_LOG_TIME);
246 if (OPT_GIVEN(LOG_TIMING))
247 daemon_set_flag(DF_LOG_TIMING);
248 daemon_set_priority(OPT_UINT32_VAL(PRIORITY));
249 if (user_list_file)
250 init_user_list(user_list_file);
251 ret = 1;
252 free_cf:
253 free(cf);
254 free(user_list_file);
255 if (ret < 0) {
256 if (errctx)
257 PARA_ERROR_LOG("%s\n", errctx);
258 free(errctx);
259 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
260 exit(EXIT_FAILURE);
261 }
262 }
263
264 /*
265 * called when server gets SIGHUP or when client invokes hup command.
266 */
267 static void handle_sighup(void)
268 {
269
270 PARA_NOTICE_LOG("SIGHUP\n");
271 parse_config_or_die(true);
272 if (afs_pid != 0)
273 kill(afs_pid, SIGHUP);
274 }
275
276 static int signal_post_select(struct sched *s, __a_unused void *context)
277 {
278 int signum = para_next_signal(&s->rfds);
279
280 switch (signum) {
281 case 0:
282 return 0;
283 case SIGHUP:
284 handle_sighup();
285 break;
286 case SIGCHLD:
287 for (;;) {
288 pid_t pid;
289 int ret = para_reap_child(&pid);
290 if (ret <= 0)
291 break;
292 if (pid != afs_pid)
293 continue;
294 PARA_EMERG_LOG("fatal: afs died\n");
295 kill(0, SIGTERM);
296 goto cleanup;
297 }
298 break;
299 /* die on sigint/sigterm. Kill all children too. */
300 case SIGINT:
301 case SIGTERM:
302 PARA_EMERG_LOG("terminating on signal %d\n", signum);
303 kill(0, SIGTERM);
304 /*
305 * We must wait for afs because afs catches SIGINT/SIGTERM.
306 * Before reacting to the signal, afs might want to use the
307 * shared memory area and the mmd mutex. If we destroy this
308 * mutex too early and afs tries to lock the shared memory
309 * area, the call to mutex_lock() will fail and terminate the
310 * afs process. This leads to dirty osl tables.
311 *
312 * There's no such problem with the other children of the
313 * server process (the command handlers) as these reset their
314 * SIGINT/SIGTERM handlers to the default action, i.e. these
315 * processes get killed immediately by the above kill().
316 */
317 PARA_INFO_LOG("waiting for afs (pid %d) to die\n",
318 (int)afs_pid);
319 waitpid(afs_pid, NULL, 0);
320 cleanup:
321 free(mmd->afd.afhi.chunk_table);
322 close_listed_fds();
323 mutex_destroy(mmd_mutex);
324 shm_detach(mmd);
325 exit(EXIT_FAILURE);
326 }
327 return 0;
328 }
329
330 static void init_signal_task(void)
331 {
332 signal_task = signal_init_or_die();
333 para_install_sighandler(SIGINT);
334 para_install_sighandler(SIGTERM);
335 para_install_sighandler(SIGHUP);
336 para_install_sighandler(SIGCHLD);
337 para_sigaction(SIGPIPE, SIG_IGN);
338 add_close_on_fork_list(signal_task->fd);
339 signal_task->task = task_register(&(struct task_info) {
340 .name = "signal",
341 .pre_select = signal_pre_select,
342 .post_select = signal_post_select,
343 .context = signal_task,
344
345 }, &sched);
346 }
347
348 static void command_pre_select(struct sched *s, void *context)
349 {
350 struct server_command_task *sct = context;
351 para_fd_set(sct->listen_fd, &s->rfds, &s->max_fileno);
352 }
353
354 static int command_post_select(struct sched *s, void *context)
355 {
356 struct server_command_task *sct = context;
357
358 int new_fd, ret, i;
359 char *peer_name;
360 pid_t child_pid;
361 uint32_t *chunk_table;
362
363 ret = para_accept(sct->listen_fd, &s->rfds, NULL, 0, &new_fd);
364 if (ret <= 0)
365 goto out;
366 mmd->num_connects++;
367 mmd->active_connections++;
368 /*
369 * The chunk table is a pointer located in the mmd struct that points
370 * to dynamically allocated memory, i.e. it must be freed by the parent
371 * and the child. However, as the mmd struct is in a shared memory
372 * area, there's no guarantee that after the fork this pointer is still
373 * valid in child context. As it is not used in the child anyway, we
374 * save it to a local variable before the fork and free the memory via
375 * that copy in the child directly after the fork.
376 */
377 chunk_table = mmd->afd.afhi.chunk_table;
378 child_pid = fork();
379 if (child_pid < 0) {
380 ret = -ERRNO_TO_PARA_ERROR(errno);
381 goto out;
382 }
383 if (child_pid) {
384 /* avoid problems with non-fork-safe PRNGs */
385 unsigned char buf[16];
386 get_random_bytes_or_die(buf, sizeof(buf));
387 close(new_fd);
388 /* parent keeps accepting connections */
389 return 0;
390 }
391 peer_name = remote_name(new_fd);
392 PARA_INFO_LOG("accepted connection from %s\n", peer_name);
393 /* mmd might already have changed at this point */
394 free(chunk_table);
395 alarm(ALARM_TIMEOUT);
396 close_listed_fds();
397 signal_shutdown(signal_task);
398 /*
399 * put info on who we are serving into argv[0] to make
400 * client ip visible in top/ps
401 */
402 for (i = sct->argc - 1; i >= 0; i--)
403 memset(sct->argv[i], 0, strlen(sct->argv[i]));
404 i = sct->argc - 1 - lls_num_inputs(cmdline_lpr);
405 sprintf(sct->argv[i], "para_server (serving %s)", peer_name);
406 handle_connect(new_fd);
407 /* never reached*/
408 out:
409 if (ret < 0)
410 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
411 return 0;
412 }
413
414 static void init_server_command_task(int argc, char **argv)
415 {
416 int ret;
417 static struct server_command_task server_command_task_struct,
418 *sct = &server_command_task_struct;
419
420 PARA_NOTICE_LOG("initializing tcp command socket\n");
421 sct->argc = argc;
422 sct->argv = argv;
423 ret = para_listen_simple(IPPROTO_TCP, OPT_UINT32_VAL(PORT));
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 sct->task = task_register(&(struct task_info) {
432 .name = "server command",
433 .pre_select = command_pre_select,
434 .post_select = command_post_select,
435 .context = sct,
436 }, &sched);
437 return;
438 err:
439 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
440 exit(EXIT_FAILURE);
441 }
442
443 static int init_afs(int argc, char **argv)
444 {
445 int ret, afs_server_socket[2];
446 char c;
447
448 ret = socketpair(PF_UNIX, SOCK_STREAM, 0, afs_server_socket);
449 if (ret < 0)
450 exit(EXIT_FAILURE);
451 get_random_bytes_or_die((unsigned char *)&afs_socket_cookie,
452 sizeof(afs_socket_cookie));
453 afs_pid = fork();
454 if (afs_pid < 0)
455 exit(EXIT_FAILURE);
456 if (afs_pid == 0) { /* child (afs) */
457 int i;
458
459 afs_pid = getpid();
460 for (i = argc - 1; i >= 0; i--)
461 memset(argv[i], 0, strlen(argv[i]));
462 i = argc - lls_num_inputs(cmdline_lpr) - 1;
463 sprintf(argv[i], "para_server (afs)");
464 close(afs_server_socket[0]);
465 afs_init(afs_server_socket[1]);
466 }
467 close(afs_server_socket[1]);
468 if (read(afs_server_socket[0], &c, 1) <= 0) {
469 PARA_EMERG_LOG("early afs exit\n");
470 exit(EXIT_FAILURE);
471 }
472 ret = mark_fd_nonblocking(afs_server_socket[0]);
473 if (ret < 0)
474 exit(EXIT_FAILURE);
475 add_close_on_fork_list(afs_server_socket[0]);
476 PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
477 afs_server_socket[0], (unsigned) afs_socket_cookie);
478 return afs_server_socket[0];
479 }
480
481 static void handle_help_flags(void)
482 {
483 char *help;
484 bool d = OPT_GIVEN(DETAILED_HELP);
485
486 if (d)
487 help = lls_long_help(CMD_PTR);
488 else if (OPT_GIVEN(HELP))
489 help = lls_short_help(CMD_PTR);
490 else
491 return;
492 printf("%s\n", help);
493 free(help);
494 exit(EXIT_SUCCESS);
495 }
496
497 static void server_init(int argc, char **argv)
498 {
499 int ret, afs_socket, daemon_pipe = -1;
500 char *errctx;
501
502 valid_fd_012();
503 /* parse command line options */
504 ret = lls(lls_parse(argc, argv, CMD_PTR, &cmdline_lpr, &errctx));
505 if (ret < 0)
506 goto fail;
507 server_lpr = cmdline_lpr;
508 daemon_set_loglevel(ENUM_STRING_VAL(LOGLEVEL));
509 daemon_drop_privileges_or_die(OPT_STRING_VAL(USER),
510 OPT_STRING_VAL(GROUP));
511 version_handle_flag("server", OPT_GIVEN(VERSION));
512 handle_help_flags();
513 parse_config_or_die(false);
514 /* become daemon */
515 if (OPT_GIVEN(DAEMON))
516 daemon_pipe = daemonize(true /* parent waits for SIGTERM */);
517 init_random_seed_or_die();
518 daemon_log_welcome("server");
519 init_ipc_or_die(); /* init mmd struct and mmd->lock */
520 daemon_set_start_time();
521 PARA_NOTICE_LOG("initializing audio format handlers\n");
522 afh_init();
523
524 /*
525 * Although afs uses its own signal handling we must ignore SIGUSR1
526 * _before_ the afs child process gets born by init_afs() below. It's
527 * racy to do this in the child because the parent might send SIGUSR1
528 * before the child gets a chance to ignore this signal.
529 *
530 * We also have to block SIGCHLD before the afs process is created
531 * because otherwise para_server does not notice if afs dies before the
532 * SIGCHLD handler has been installed for the parent process by
533 * init_signal_task() below.
534 */
535 para_sigaction(SIGUSR1, SIG_IGN);
536 para_block_signal(SIGCHLD);
537 PARA_NOTICE_LOG("initializing the audio file selector\n");
538 afs_socket = init_afs(argc, argv);
539 init_signal_task();
540 para_unblock_signal(SIGCHLD);
541 PARA_NOTICE_LOG("initializing virtual streaming system\n");
542 vss_init(afs_socket, &sched);
543 init_server_command_task(argc, argv);
544 if (daemon_pipe >= 0) {
545 if (write(daemon_pipe, "\0", 1) < 0) {
546 PARA_EMERG_LOG("daemon_pipe: %s", strerror(errno));
547 exit(EXIT_FAILURE);
548 }
549 close(daemon_pipe);
550 }
551 PARA_NOTICE_LOG("server init complete\n");
552 return;
553 fail:
554 assert(ret < 0);
555 if (errctx)
556 PARA_ERROR_LOG("%s\n", errctx);
557 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
558 exit(EXIT_FAILURE);
559 }
560
561 static void status_refresh(void)
562 {
563 static int prev_uptime = -1, prev_events = -1;
564 int uptime = daemon_get_uptime(now);
565
566 if (prev_events != mmd->events)
567 goto out;
568 if (mmd->new_vss_status_flags != mmd->vss_status_flags)
569 goto out_inc_events;
570 if (uptime / 60 != prev_uptime / 60)
571 goto out_inc_events;
572 return;
573 out_inc_events:
574 mmd->events++;
575 out:
576 prev_uptime = uptime;
577 prev_events = mmd->events;
578 mmd->vss_status_flags = mmd->new_vss_status_flags;
579 PARA_DEBUG_LOG("%u events, forcing status update\n", mmd->events);
580 killpg(0, SIGUSR1);
581 }
582
583 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
584 struct timeval *timeout_tv)
585 {
586 int ret;
587
588 status_refresh();
589 mutex_unlock(mmd_mutex);
590 ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
591 mutex_lock(mmd_mutex);
592 return ret;
593 }
594
595 /**
596 * The main function of para_server.
597 *
598 * \param argc Usual argument count.
599 * \param argv Usual argument vector.
600 *
601 * \return EXIT_SUCCESS or EXIT_FAILURE.
602 */
603 int main(int argc, char *argv[])
604 {
605 int ret;
606
607 sched.default_timeout.tv_sec = 1;
608 sched.select_function = server_select;
609
610 server_init(argc, argv);
611 mutex_lock(mmd_mutex);
612 ret = schedule(&sched);
613 sched_shutdown(&sched);
614 lls_free_parse_result(server_lpr, CMD_PTR);
615 if (server_lpr != cmdline_lpr)
616 lls_free_parse_result(cmdline_lpr, CMD_PTR);
617 if (ret < 0)
618 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
619 exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);
620 }