1 /* Copyright (C) 1997 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
3 /** \file server.c Paraslash's main server. */
5 #include <netinet/in.h>
6 #include <sys/socket.h>
10 #include <sys/types.h>
11 #include <arpa/inet.h>
16 #include "server.lsg.h"
31 #include "close_on_fork.h"
36 #include "user_list.h"
40 /** Array of error strings. */
43 __printf_2_3 void (*para_log)(int, const char*, ...) = daemon_log;
45 /** Shut down non-authorized connections after that many seconds. */
46 #define ALARM_TIMEOUT 10
49 * Pointer to shared memory area for communication between para_server
50 * and its children. Exported to vss.c, command.c and to afs.
52 struct misc_meta_data *mmd;
55 * The active value for all config options of para_server.
57 * It is computed by merging the parse result of the command line options with
58 * the parse result of the config file.
60 struct lls_parse_result *server_lpr = NULL;
62 /* Command line options (no config file options). Used in handle_sighup(). */
63 static struct lls_parse_result *cmdline_lpr;
66 * A random number used to "authenticate" the afs connection.
68 * para_server picks this number by random before it forks the afs process. The
69 * command handlers know this number as well and write it to the afs socket,
70 * together with the id of the shared memory area which contains the payload of
71 * the afs command. A local process has to know this number to abuse the afs
72 * service provided by the local socket.
74 uint32_t afs_socket_cookie;
76 /** The mutex protecting the shared memory area containing the mmd struct. */
79 /* Serializes log output. */
82 static struct sched sched;
83 static struct signal_task *signal_task;
85 /** The process id of the audio file selector process. */
88 /* The main server process (parent of afs and the command handlers). */
89 static pid_t server_pid;
92 * Tell whether the executing process is a command handler.
94 * Cleanup on exit must be performed differently for command handlers.
96 * \return True if the pid of the executing process is neither the server pid
99 bool process_is_command_handler(void)
101 pid_t pid = getpid();
103 return pid != afs_pid && pid != server_pid;
106 /** The task responsible for server command handling. */
107 struct server_command_task {
108 unsigned num_listen_fds; /* only one by default */
109 /** TCP socket(s) on which para_server listens for connections. */
111 /* File descriptor for the accepted socket. */
113 /** Copied from para_server's main function. */
115 /** Argument vector passed to para_server's main function. */
117 /** The command task structure for scheduling. */
122 * Return the list of tasks for the server process.
124 * This is called from \a com_tasks(). The helper is necessary since command
125 * handlers can not access the scheduler structure directly.
127 * \return A dynamically allocated string that must be freed by the caller.
129 char *server_get_tasks(void)
131 return get_task_list(&sched);
134 static void pre_log_hook(void)
136 mutex_lock(log_mutex);
139 static void post_log_hook(void)
141 mutex_unlock(log_mutex);
144 /* Setup shared memory area and init mutexes */
145 static void init_ipc_or_die(void)
148 int shmid, ret = shm_new(sizeof(struct misc_meta_data));
153 ret = shm_attach(shmid, ATTACH_RW, &shm);
165 goto destroy_mmd_mutex;
169 mmd->num_commands = 0;
171 mmd->num_connects = 0;
172 mmd->active_connections = 0;
173 mmd->vss_status_flags = VSS_NEXT;
174 mmd->new_vss_status_flags = VSS_NEXT;
177 mutex_destroy(mmd_mutex);
179 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
184 * (Re-)read the server configuration files.
186 * \param reload Whether config file overrides command line.
188 * This function also re-opens the logfile and the user list. On SIGHUP it is
189 * called from both server and afs context.
191 void parse_config_or_die(bool reload)
194 unsigned flags = MCF_DONT_FREE;
196 if (server_lpr != cmdline_lpr)
197 lls_free_parse_result(server_lpr, CMD_PTR);
198 server_lpr = cmdline_lpr;
200 flags |= MCF_OVERRIDE;
201 ret = lsu_merge_config_file_options(OPT_STRING_VAL(CONFIG_FILE),
202 "server.conf", &server_lpr, CMD_PTR, server_suite, flags);
204 PARA_EMERG_LOG("failed to parse config file: %s\n",
205 para_strerror(-ret));
208 daemon_set_loglevel(ENUM_STRING_VAL(LOGLEVEL));
209 if (OPT_GIVEN(LOGFILE)) {
210 daemon_set_logfile(OPT_STRING_VAL(LOGFILE));
211 daemon_open_log_or_die();
213 if (daemon_init_colors_or_die(OPT_UINT32_VAL(COLOR), COLOR_AUTO,
214 COLOR_NO, OPT_GIVEN(LOGFILE))) {
216 for (i = 0; i < OPT_GIVEN(LOG_COLOR); i++)
217 daemon_set_log_color_or_die(lls_string_val(i,
218 OPT_RESULT(LOG_COLOR)));
220 daemon_set_flag(DF_LOG_PID);
221 daemon_set_flag(DF_LOG_LL);
222 daemon_set_flag(DF_LOG_TIME);
223 if (OPT_GIVEN(LOG_TIMING))
224 daemon_set_flag(DF_LOG_TIMING);
225 daemon_set_priority(OPT_UINT32_VAL(PRIORITY));
226 if (!reload || getpid() != afs_pid) {
227 char *user_list_file;
228 if (OPT_GIVEN(USER_LIST))
229 user_list_file = para_strdup(OPT_STRING_VAL(USER_LIST));
231 char *home = para_homedir();
232 user_list_file = make_message("%s/.paraslash/server.users", home);
235 user_list_init(user_list_file);
236 free(user_list_file);
242 * called when server gets SIGHUP or when client invokes hup command.
244 static void handle_sighup(void)
247 PARA_NOTICE_LOG("SIGHUP\n");
248 parse_config_or_die(true);
250 kill(afs_pid, SIGHUP);
253 static int signal_post_select(struct sched *s, __a_unused void *context)
257 ret = task_get_notification(signal_task->task);
260 signum = para_next_signal(&s->rfds);
270 ret = para_reap_child(&pid);
275 PARA_EMERG_LOG("fatal: afs died\n");
279 /* die on sigint/sigterm. Kill all children too. */
282 PARA_EMERG_LOG("terminating on signal %d\n", signum);
286 * We must wait for all of our children to die. For the afs
287 * process or a command handler might want to use the
288 * shared memory area and the mmd mutex. If we destroy this
289 * mutex too early and afs tries to lock the shared memory
290 * area, the call to mutex_lock() will fail and terminate the
291 * afs process. This leads to dirty osl tables.
293 PARA_INFO_LOG("waiting for child processes to die\n");
294 mutex_unlock(mmd_mutex);
295 while (wait(NULL) != -1 || errno != ECHILD)
296 ; /* still at least one child alive */
297 mutex_lock(mmd_mutex);
298 free(mmd->afd.afhi.chunk_table);
299 task_notify_all(s, E_DEADLY_SIGNAL);
300 return -E_DEADLY_SIGNAL;
305 static void init_signal_task(void)
307 signal_task = signal_init_or_die();
308 para_install_sighandler(SIGINT);
309 para_install_sighandler(SIGTERM);
310 para_install_sighandler(SIGHUP);
311 para_install_sighandler(SIGCHLD);
312 para_sigaction(SIGPIPE, SIG_IGN);
313 add_close_on_fork_list(signal_task->fd);
314 signal_task->task = task_register(&(struct task_info) {
316 .pre_select = signal_pre_select,
317 .post_select = signal_post_select,
318 .context = signal_task,
323 static void command_pre_select(struct sched *s, void *context)
326 struct server_command_task *sct = context;
328 for (n = 0; n < sct->num_listen_fds; n++)
329 para_fd_set(sct->listen_fds[n], &s->rfds, &s->max_fileno);
332 static int command_task_accept(unsigned listen_idx, struct sched *s,
333 struct server_command_task *sct)
338 uint32_t *chunk_table;
340 ret = para_accept(sct->listen_fds[listen_idx], &s->rfds, NULL, 0, &new_fd);
344 mmd->active_connections++;
346 * The chunk table is a pointer located in the mmd struct that points
347 * to dynamically allocated memory, i.e. it must be freed by the parent
348 * and the child. However, as the mmd struct is in a shared memory
349 * area, there's no guarantee that after the fork this pointer is still
350 * valid in child context. As it is not used in the child anyway, we
351 * save it to a local variable before the fork and free the memory via
352 * that copy in the child directly after the fork.
354 chunk_table = mmd->afd.afhi.chunk_table;
357 ret = -ERRNO_TO_PARA_ERROR(errno);
361 /* avoid problems with non-fork-safe PRNGs */
362 unsigned char buf[16];
363 get_random_bytes_or_die(buf, sizeof(buf));
365 /* parent keeps accepting connections */
368 peer_name = remote_name(new_fd);
369 PARA_INFO_LOG("accepted connection from %s\n", peer_name);
370 /* mmd might already have changed at this point */
372 sct->child_fd = new_fd;
374 * put info on who we are serving into argv[0] to make
375 * client ip visible in top/ps
377 for (i = sct->argc - 1; i >= 0; i--)
378 memset(sct->argv[i], 0, strlen(sct->argv[i]));
379 i = sct->argc - 1 - lls_num_inputs(cmdline_lpr);
380 sprintf(sct->argv[i], "para_server (serving %s)", peer_name);
381 /* ask other tasks to terminate */
382 task_notify_all(s, E_CHILD_CONTEXT);
384 * After we return, the scheduler calls server_select() with a minimal
385 * timeout value, because the remaining tasks have a notification
386 * pending. Next it calls the ->post_select method of these tasks,
387 * which will return negative in view of the notification. This causes
388 * schedule() to return as there are no more runnable tasks.
390 * Note that semaphores are not inherited across a fork(), so we don't
391 * hold the lock at this point. Since server_select() drops the lock
392 * prior to calling para_select(), we need to acquire it here.
394 mutex_lock(mmd_mutex);
395 return -E_CHILD_CONTEXT;
398 PARA_CRIT_LOG("%s\n", para_strerror(-ret));
402 static int command_post_select(struct sched *s, void *context)
404 struct server_command_task *sct = context;
408 ret = task_get_notification(sct->task);
411 for (n = 0; n < sct->num_listen_fds; n++) {
412 ret = command_task_accept(n, s, sct);
414 free(sct->listen_fds);
421 static void init_server_command_task(struct server_command_task *sct,
422 int argc, char **argv)
426 uint32_t port = OPT_UINT32_VAL(PORT);
428 PARA_NOTICE_LOG("initializing tcp command socket\n");
432 if (!OPT_GIVEN(LISTEN_ADDRESS)) {
433 sct->num_listen_fds = 1;
434 sct->listen_fds = para_malloc(sizeof(int));
435 ret = para_listen_simple(IPPROTO_TCP, port);
438 sct->listen_fds[0] = ret;
440 sct->num_listen_fds = OPT_GIVEN(LISTEN_ADDRESS);
441 sct->listen_fds = para_malloc(sct->num_listen_fds * sizeof(int));
442 for (n = 0; n < OPT_GIVEN(LISTEN_ADDRESS); n++) {
444 arg = lls_string_val(n, OPT_RESULT(LISTEN_ADDRESS));
445 ret = para_listen(IPPROTO_TCP, arg, port);
448 sct->listen_fds[n] = ret;
451 for (n = 0; n < sct->num_listen_fds; n++) {
452 ret = mark_fd_nonblocking(sct->listen_fds[n]);
455 /* child doesn't need the listener */
456 add_close_on_fork_list(sct->listen_fds[n]);
459 sct->task = task_register(&(struct task_info) {
460 .name = "server command",
461 .pre_select = command_pre_select,
462 .post_select = command_post_select,
466 * Detect whether the abstract Unix domain socket space is supported,
467 * but do not create the socket. We check this once in server context
468 * so that the command handlers inherit this bit of information and
469 * don't need to check again.
471 create_local_socket(NULL);
474 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
478 static int init_afs(int argc, char **argv)
480 int ret, afs_server_socket[2];
483 ret = socketpair(PF_UNIX, SOCK_STREAM, 0, afs_server_socket);
486 get_random_bytes_or_die((unsigned char *)&afs_socket_cookie,
487 sizeof(afs_socket_cookie));
491 if (afs_pid == 0) { /* child (afs) */
497 for (i = argc - 1; i >= 0; i--)
498 memset(argv[i], 0, strlen(argv[i]));
499 i = argc - lls_num_inputs(cmdline_lpr) - 1;
500 sprintf(argv[i], "para_server (afs)");
501 close(afs_server_socket[0]);
502 afs_init(afs_server_socket[1]);
504 close(afs_server_socket[1]);
505 if (read(afs_server_socket[0], &c, 1) <= 0) {
506 PARA_EMERG_LOG("early afs exit\n");
509 ret = mark_fd_nonblocking(afs_server_socket[0]);
512 add_close_on_fork_list(afs_server_socket[0]);
513 PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n",
514 afs_server_socket[0], (unsigned) afs_socket_cookie);
515 return afs_server_socket[0];
518 static void handle_help_flags(void)
521 bool d = OPT_GIVEN(DETAILED_HELP);
524 help = lls_long_help(CMD_PTR);
525 else if (OPT_GIVEN(HELP))
526 help = lls_short_help(CMD_PTR);
529 printf("%s\n", help);
534 static void server_init(int argc, char **argv, struct server_command_task *sct)
536 int ret, afs_socket, daemon_pipe = -1;
540 /* parse command line options */
541 ret = lls(lls_parse(argc, argv, CMD_PTR, &cmdline_lpr, &errctx));
544 server_lpr = cmdline_lpr;
545 daemon_set_loglevel(ENUM_STRING_VAL(LOGLEVEL));
546 daemon_drop_privileges_or_die(OPT_STRING_VAL(USER),
547 OPT_STRING_VAL(GROUP));
548 version_handle_flag("server", OPT_GIVEN(VERSION));
550 parse_config_or_die(false);
552 if (OPT_GIVEN(DAEMON))
553 daemon_pipe = daemonize(true /* parent waits for SIGTERM */);
554 server_pid = getpid();
556 daemon_log_welcome("server");
557 init_ipc_or_die(); /* init mmd struct, mmd and log mutex */
558 daemon_set_start_time();
559 daemon_set_hooks(pre_log_hook, post_log_hook);
561 * Although afs uses its own signal handling we must ignore SIGUSR1
562 * _before_ the afs child process gets born by init_afs() below. It's
563 * racy to do this in the child because the parent might send SIGUSR1
564 * before the child gets a chance to ignore this signal.
566 * We also have to block SIGCHLD before the afs process is created
567 * because otherwise para_server does not notice if afs dies before the
568 * SIGCHLD handler has been installed for the parent process by
569 * init_signal_task() below.
571 para_sigaction(SIGUSR1, SIG_IGN);
572 para_block_signal(SIGCHLD);
573 PARA_NOTICE_LOG("initializing the audio file selector\n");
574 afs_socket = init_afs(argc, argv);
576 para_unblock_signal(SIGCHLD);
577 PARA_NOTICE_LOG("initializing virtual streaming system\n");
578 vss_init(afs_socket, &sched);
579 init_server_command_task(sct, argc, argv);
580 if (daemon_pipe >= 0) {
581 if (write(daemon_pipe, "\0", 1) < 0) {
582 PARA_EMERG_LOG("daemon_pipe: %s", strerror(errno));
587 PARA_NOTICE_LOG("server init complete\n");
592 PARA_ERROR_LOG("%s\n", errctx);
593 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
597 static void status_refresh(void)
599 static int prev_uptime = -1, prev_events = -1;
600 int uptime = daemon_get_uptime(now);
602 if (prev_events != mmd->events)
604 if (mmd->new_vss_status_flags != mmd->vss_status_flags)
606 if (uptime / 60 != prev_uptime / 60)
612 prev_uptime = uptime;
613 prev_events = mmd->events;
614 mmd->vss_status_flags = mmd->new_vss_status_flags;
615 PARA_DEBUG_LOG("%u events, forcing status update\n", mmd->events);
619 static int server_select(int max_fileno, fd_set *readfds, fd_set *writefds,
620 struct timeval *timeout_tv)
625 mutex_unlock(mmd_mutex);
626 ret = para_select(max_fileno + 1, readfds, writefds, timeout_tv);
627 mutex_lock(mmd_mutex);
632 * Deallocate all lopsub parse results.
634 * The server allocates a parse result for command line options and optionally
635 * a second parse result for the effective configuration, defined by merging
636 * the command line options with the options stored in the configuration file.
637 * This function frees both structures.
641 lls_free_parse_result(server_lpr, CMD_PTR);
642 if (server_lpr != cmdline_lpr)
643 lls_free_parse_result(cmdline_lpr, CMD_PTR);
647 * The main function of para_server.
649 * \param argc Usual argument count.
650 * \param argv Usual argument vector.
652 * \return EXIT_SUCCESS or EXIT_FAILURE.
654 int main(int argc, char *argv[])
657 struct server_command_task server_command_task_struct,
658 *sct = &server_command_task_struct;
660 sched.default_timeout.tv_sec = 1;
661 sched.select_function = server_select;
663 server_init(argc, argv, sct);
664 mutex_lock(mmd_mutex);
665 ret = schedule(&sched);
667 * We hold the mmd lock: it was re-acquired in server_select()
668 * after the select call.
670 mutex_unlock(mmd_mutex);
671 sched_shutdown(&sched);
673 signal_shutdown(signal_task);
674 if (!process_is_command_handler()) { /* parent (server) */
675 mutex_destroy(mmd_mutex);
676 daemon_set_hooks(NULL, NULL); /* only one process remaining */
677 mutex_destroy(log_mutex);
678 deplete_close_on_fork_list();
680 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
682 alarm(ALARM_TIMEOUT);
684 ret = handle_connect(sct->child_fd);
690 exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);