Fix an invalid free() in command handlers.
[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 *
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 goto genocide;
295 }
296 break;
297 /* die on sigint/sigterm. Kill all children too. */
298 case SIGINT:
299 case SIGTERM:
300 PARA_EMERG_LOG("terminating on signal %d\n", st->signum);
301 genocide:
302 kill(0, SIGTERM);
303 free(mmd->afd.afhi.chunk_table);
304 free(mmd->afd.afhi.info_string);
305 close_listed_fds();
306 mutex_destroy(mmd_mutex);
307 shm_detach(mmd);
308 exit(EXIT_FAILURE);
309 }
310 }
311
312 static void init_signal_task(void)
313 {
314 static struct signal_task signal_task_struct,
315 *st = &signal_task_struct;
316
317 st->task.pre_select = signal_pre_select;
318 st->task.post_select = signal_post_select;
319 sprintf(st->task.status, "signal task");
320
321 st->fd = para_signal_init(); /* always successful */
322
323 PARA_NOTICE_LOG("setting up signal handlers\n");
324 if (para_install_sighandler(SIGINT) < 0)
325 goto err;
326 if (para_install_sighandler(SIGTERM) < 0)
327 goto err;
328 if (para_install_sighandler(SIGHUP) < 0)
329 goto err;
330 if (para_install_sighandler(SIGCHLD) < 0)
331 goto err;
332 if (signal(SIGPIPE, SIG_IGN) == SIG_ERR)
333 goto err;
334 add_close_on_fork_list(st->fd);
335 register_task(&st->task);
336 return;
337 err:
338 PARA_EMERG_LOG("could not install signal handlers\n");
339 exit(EXIT_FAILURE);
340 }
341
342 static void command_pre_select(struct sched *s, struct task *t)
343 {
344 struct server_command_task *sct = container_of(t, struct server_command_task, task);
345 para_fd_set(sct->listen_fd, &s->rfds, &s->max_fileno);
346 }
347
348 static void command_post_select(struct sched *s, struct task *t)
349 {
350 struct server_command_task *sct = container_of(t, struct server_command_task, task);
351
352 int new_fd, ret, i;
353 char *peer_name;
354 pid_t child_pid;
355 uint32_t *chunk_table;
356 char *info_string;
357
358 if (!FD_ISSET(sct->listen_fd, &s->rfds))
359 return;
360 ret = para_accept(sct->listen_fd, NULL, 0);
361 if (ret < 0)
362 goto out;
363 new_fd = ret;
364 peer_name = remote_name(new_fd);
365 PARA_INFO_LOG("got connection from %s, forking\n", peer_name);
366 mmd->num_connects++;
367 mmd->active_connections++;
368 random();
369 /* The chunk table and the info_string are pointers located in the
370 * mmd struct that point to dynamically allocated memory that must be
371 * freed by the parent and the child. However, as the mmd struct is in
372 * a shared memory area, there's no guarantee that after the fork these
373 * pointers are still valid in child context. As these two pointers are
374 * not used in the child anyway, we save them to local variables and
375 * free the memory via that copy in the child.
376 */
377 info_string = mmd->afd.afhi.info_string;
378 chunk_table = mmd->afd.afhi.chunk_table;
379 child_pid = fork();
380 if (child_pid < 0) {
381 ret = -ERRNO_TO_PARA_ERROR(errno);
382 goto out;
383 }
384 if (child_pid) {
385 close(new_fd);
386 /* parent keeps accepting connections */
387 return;
388 }
389 /* mmd might already have changed at this point */
390 free(info_string);
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 return handle_connect(new_fd, peer_name);
403 out:
404 if (ret < 0)
405 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
406 }
407
408 static void init_server_command_task(int argc, char **argv)
409 {
410 int ret;
411 static struct server_command_task server_command_task_struct,
412 *sct = &server_command_task_struct;
413
414 PARA_NOTICE_LOG("initializing tcp command socket\n");
415 sct->task.pre_select = command_pre_select;
416 sct->task.post_select = command_post_select;
417 sct->argc = argc;
418 sct->argv = argv;
419 ret = para_listen(AF_UNSPEC, 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 register_task(&sct->task);
428 return;
429 err:
430 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
431 exit(EXIT_FAILURE);
432 }
433
434 static void init_random_seed(void)
435 {
436 unsigned int seed;
437 int fd, ret = para_open("/dev/urandom", O_RDONLY, 0);
438
439 if (ret < 0)
440 goto err;
441 fd = ret;
442 ret = read(fd, &seed, sizeof(seed));
443 if (ret < 0) {
444 ret = -ERRNO_TO_PARA_ERROR(errno);
445 goto out;
446 }
447 if (ret != sizeof(seed)) {
448 ret = -ERRNO_TO_PARA_ERROR(EIO);
449 goto out;
450 }
451 srandom(seed);
452 ret = 1;
453 out:
454 close(fd);
455 if (ret >= 0)
456 return;
457 err:
458 PARA_EMERG_LOG("can not seed pseudo random number generator: %s\n",
459 para_strerror(-ret));
460 exit(EXIT_FAILURE);
461 }
462
463 static int init_afs(void)
464 {
465 int ret, afs_server_socket[2];
466
467 ret = socketpair(PF_UNIX, SOCK_DGRAM, 0, afs_server_socket);
468 if (ret < 0)
469 exit(EXIT_FAILURE);
470 afs_socket_cookie = para_random((uint32_t)-1);
471 mmd->afs_pid = fork();
472 if (mmd->afs_pid < 0)
473 exit(EXIT_FAILURE);
474 if (!mmd->afs_pid) { /* child (afs) */
475 close(afs_server_socket[0]);
476 afs_init(afs_socket_cookie, afs_server_socket[1]);
477 }
478 close(afs_server_socket[1]);
479 ret = mark_fd_nonblocking(afs_server_socket[0]);
480 if (ret < 0)
481 exit(EXIT_FAILURE);
482 add_close_on_fork_list(afs_server_socket[0]);
483 PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
484 afs_server_socket[0], (unsigned) afs_socket_cookie);
485 return afs_server_socket[0];
486 }
487
488 __noreturn static void tmp_sigchld_handler(__a_unused int s)
489 {
490 PARA_EMERG_LOG("caught early SIGCHLD\n");
491 exit(EXIT_FAILURE);
492 }
493
494 static void server_init(int argc, char **argv)
495 {
496 struct server_cmdline_parser_params params = {
497 .override = 0,
498 .initialize = 1,
499 .check_required = 0,
500 .check_ambiguity = 0,
501 .print_errors = 1
502 };
503 int afs_socket;
504
505 valid_fd_012();
506 init_random_seed();
507 /* parse command line options */
508 server_cmdline_parser_ext(argc, argv, &conf, &params);
509 HANDLE_VERSION_FLAG("server", conf);
510 drop_privileges_or_die(conf.user_arg, conf.group_arg);
511 /* parse config file, open log and set defaults */
512 parse_config_or_die(0);
513 log_welcome("para_server");
514 init_ipc_or_die(); /* init mmd struct and mmd->lock */
515 /* make sure, the global now pointer is uptodate */
516 gettimeofday(now, NULL);
517 server_uptime(UPTIME_SET); /* reset server uptime */
518 init_user_list(user_list_file);
519 /* become daemon */
520 if (conf.daemon_given)
521 daemonize();
522 PARA_NOTICE_LOG("initializing audio format handlers\n");
523 afh_init();
524
525 /*
526 * Although afs uses its own signal handling we must ignore SIGUSR1
527 * _before_ the afs child process gets born by init_afs() below. It's
528 * racy to do this in the child because the parent might send SIGUSR1
529 * before the child gets a chance to ignore this signal -- only the
530 * good die young.
531 */
532 if (signal(SIGUSR1, SIG_IGN) == SIG_ERR) {
533 PARA_EMERG_LOG("failed to ignore SIGUSR1\n");
534 exit(EXIT_FAILURE);
535 }
536 /*
537 * We have to install a SIGCHLD handler before the afs process is being
538 * forked off. Otherwise, para_server does not notice if afs dies before
539 * the SIGCHLD handler has been installed by init_signal_task() below.
540 */
541 if (signal(SIGCHLD, tmp_sigchld_handler) == SIG_ERR) {
542 PARA_EMERG_LOG("failed to install temporary SIGCHLD handler\n");
543 exit(EXIT_FAILURE);
544 }
545 PARA_NOTICE_LOG("initializing the audio file selector\n");
546 afs_socket = init_afs();
547 init_signal_task();
548 PARA_NOTICE_LOG("initializing virtual streaming system\n");
549 init_vss_task(afs_socket);
550 init_server_command_task(argc, argv);
551 PARA_NOTICE_LOG("server init complete\n");
552 }
553
554 static void status_refresh(void)
555 {
556 static int prev_uptime = -1, prev_events = -1;
557 int uptime = server_uptime(UPTIME_GET), ret = 1;
558
559 if (prev_events != mmd->events)
560 goto out;
561 if (mmd->new_vss_status_flags != mmd->vss_status_flags)
562 goto out_inc_events;
563 if (uptime / 60 != prev_uptime / 60)
564 goto out_inc_events;
565 return;
566 out_inc_events:
567 mmd->events++;
568 out:
569 prev_uptime = uptime;
570 prev_events = mmd->events;
571 mmd->vss_status_flags = mmd->new_vss_status_flags;
572 if (ret) {
573 PARA_DEBUG_LOG("%d events, forcing status update\n",
574 mmd->events);
575 killpg(0, SIGUSR1);
576 }
577 }
578
579 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
580 struct timeval *timeout_tv)
581 {
582 int ret;
583
584 status_refresh();
585 mutex_unlock(mmd_mutex);
586 ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
587 mutex_lock(mmd_mutex);
588 return ret;
589 }
590
591 /**
592 * The main function of para_server.
593 *
594 * \param argc Usual argument count.
595 * \param argv Usual argument vector.
596 *
597 * \return EXIT_SUCCESS or EXIT_FAILURE.
598 */
599 int main(int argc, char *argv[])
600 {
601 int ret;
602 static struct sched s = {
603 .default_timeout = {
604 .tv_sec = 1,
605 .tv_usec = 0
606 },
607 .select_function = server_select
608 };
609 server_init(argc, argv);
610 mutex_lock(mmd_mutex);
611 ret = schedule(&s);
612 if (ret < 0) {
613 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
614 exit(EXIT_FAILURE);
615 }
616 exit(EXIT_SUCCESS);
617 }