Fix a use-after-free bug in para_server.
[paraslash.git] / server.c
1 /*
2 * Copyright (C) 1997-2007 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 /** \mainpage Paraslash API Reference
11 *
12 * Good starting points for reading are probably \ref audio_file_selector,
13 * \ref sender, \ref receiver, \ref receiver_node, \ref filter, \ref
14 * filter_node.
15 *
16 */
17
18 #include <signal.h>
19 #include <sys/types.h>
20 #include <dirent.h>
21
22 #include "para.h"
23 #include "error.h"
24 #include "server.cmdline.h"
25 #include "afh.h"
26 #include "string.h"
27 #include "afs.h"
28 #include "server.h"
29 #include "vss.h"
30 #include "config.h"
31 #include "close_on_fork.h"
32 #include "send.h"
33 #include "net.h"
34 #include "daemon.h"
35 #include "ipc.h"
36 #include "fd.h"
37 #include "list.h"
38 #include "sched.h"
39 #include "signal.h"
40 #include "user_list.h"
41
42 /** define the array of error lists needed by para_server */
43 INIT_SERVER_ERRLISTS;
44
45 /** shut down non-authorized connections after that many seconds */
46 #define ALARM_TIMEOUT 10
47
48 /**
49 * pointer to shared memory area for communication between para_server
50 * and its children. exported to vss.c. command.c and to all selectors.
51 */
52 struct misc_meta_data *mmd;
53
54 /**
55 * the configuration of para_server
56 *
57 * It also contains the options for all audio file selectors, audio format handler
58 * and all supported senders.
59 */
60 struct server_args_info conf;
61
62 /** the file containing user information (public key, permissions) */
63 char *user_list_file = NULL;
64
65 extern void dccp_send_init(struct sender *);
66 extern void http_send_init(struct sender *);
67 extern void ortp_send_init(struct sender *);
68
69 /** the list of supported senders */
70 struct sender senders[] = {
71 {
72 .name = "http",
73 .init = http_send_init,
74 },
75 {
76 .name = "dccp",
77 .init = dccp_send_init,
78 },
79 #ifdef HAVE_ORTP
80 {
81 .name = "ortp",
82 .init = ortp_send_init,
83 },
84 #endif
85 {
86 .name = NULL,
87 }
88 };
89
90
91 /* global variables for server-internal use */
92 static FILE *logfile;
93 static int mmd_mutex, mmd_shm_id;
94 static int signal_pipe;
95
96 /**
97 * para_server's log function
98 *
99 * \param ll the log level
100 * \param fmt the format string describing the log message
101 */
102 void para_log(int ll, const char* fmt,...)
103 {
104 va_list argp;
105 FILE *outfd;
106 struct tm *tm;
107 time_t t1;
108 char str[MAXLINE] = "";
109 pid_t mypid;
110
111 if (ll < conf.loglevel_arg)
112 return;
113 outfd = logfile? logfile : stderr;
114 time(&t1);
115 tm = localtime(&t1);
116 strftime(str, MAXLINE, "%b %d %H:%M:%S", tm);
117 fprintf(outfd, "%s ", str);
118 if (conf.loglevel_arg <= INFO)
119 fprintf(outfd, "%i: ", ll);
120 mypid = getpid();
121 if (conf.loglevel_arg <= INFO)
122 fprintf(outfd, "(%d) ", mypid);
123 va_start(argp, fmt);
124 vfprintf(outfd, fmt, argp);
125 va_end(argp);
126 }
127
128 /*
129 * setup shared memory area and get mutex for locking
130 */
131 static void shm_init(void)
132 {
133 void *shm;
134 int ret = shm_new(sizeof(struct misc_meta_data));
135
136 if (ret < 0)
137 goto err_out;
138
139 ret = shm_attach(ret, ATTACH_RW, &shm);
140 if (ret < 0)
141 goto err_out;
142 mmd = shm;
143 mmd_shm_id = ret;
144
145 ret = mutex_new();
146 if (ret < 0)
147 goto err_out;
148 mmd_mutex = ret;
149
150 mmd->num_played = 0;
151 mmd->num_commands = 0;
152 mmd->events = 0;
153 mmd->num_connects = 0;
154 mmd->active_connections = 0;
155 strcpy(mmd->afd.path, "(none)");
156 mmd->vss_status_flags = VSS_NEXT;
157 mmd->new_vss_status_flags = VSS_NEXT;
158 mmd->sender_cmd_data.cmd_num = -1;
159 return;
160 err_out:
161 PARA_EMERG_LOG("%s", PARA_STRERROR(-ret));
162 exit(EXIT_FAILURE);
163 }
164
165 /**
166 * lock the shared memory area containing the mmd struct
167 *
168 * \sa semop(2), struct misc_meta_data
169 */
170 void mmd_lock(void)
171 {
172 mutex_lock(mmd_mutex);
173 }
174
175 /**
176 * unlock the shared memory area containing the mmd struct
177 *
178 * \sa semop(2), struct misc_meta_data
179 */
180
181 void mmd_unlock(void)
182 {
183 mutex_unlock(mmd_mutex);
184 }
185
186 static void parse_config(int override)
187 {
188 char *home = para_homedir();
189 struct stat statbuf;
190 int ret;
191 char *cf;
192
193 if (conf.config_file_given)
194 cf = para_strdup(conf.config_file_arg);
195 else
196 cf = make_message("%s/.paraslash/server.conf", home);
197 free(user_list_file);
198 if (!conf.user_list_given)
199 user_list_file = make_message("%s/.paraslash/server.users", home);
200 else
201 user_list_file = para_strdup(conf.user_list_arg);
202 ret = stat(cf, &statbuf);
203 if (ret && conf.config_file_given) {
204 ret = -1;
205 PARA_EMERG_LOG("can not stat config file %s\n", cf);
206 goto out;
207 }
208 if (!ret) {
209 int tmp = conf.daemon_given;
210 struct server_cmdline_parser_params params = {
211 .override = override,
212 .initialize = 0,
213 .check_required = 0,
214 .check_ambiguity = 0
215 };
216 server_cmdline_parser_config_file(cf, &conf, &params);
217 conf.daemon_given = tmp;
218 }
219 /* logfile */
220 if (!conf.logfile_given && conf.daemon_given) {
221 ret = -1;
222 PARA_EMERG_LOG("%s", "daemon, but no log file\n");
223 goto out;
224 }
225 if (conf.logfile_given)
226 logfile = open_log(conf.logfile_arg);
227 ret = 1;
228 out:
229 free(cf);
230 free(home);
231 if (ret > 0)
232 return;
233 free(user_list_file);
234 user_list_file = NULL;
235 exit(EXIT_FAILURE);
236 }
237
238 static void setup_signal_handling(void)
239 {
240 int ret = 0;
241
242 signal_pipe = para_signal_init();
243 PARA_NOTICE_LOG("%s", "setting up signal handlers\n");
244 ret += para_install_sighandler(SIGINT);
245 ret += para_install_sighandler(SIGTERM);
246 ret += para_install_sighandler(SIGHUP);
247 ret += para_install_sighandler(SIGCHLD);
248 ret += para_install_sighandler(SIGUSR1);
249 signal(SIGPIPE, SIG_IGN);
250 if (ret != 5) {
251 PARA_EMERG_LOG("%s", "could not install signal handlers\n");
252 exit(EXIT_FAILURE);
253 }
254 }
255
256 static unsigned init_network(void)
257 {
258 int fd, ret = init_tcp_socket(conf.port_arg);
259
260 if (ret < 0)
261 goto err;
262 fd = ret;
263 ret = mark_fd_nonblock(fd);
264 if (ret < 0)
265 goto err;
266 return fd;
267 err:
268 PARA_EMERG_LOG("%s\n", PARA_STRERROR(-ret));
269 exit(EXIT_FAILURE);
270 }
271
272 static void init_random_seed(void)
273 {
274 int fd, ret = -1;
275 unsigned int seed;
276 size_t len = sizeof(unsigned int);
277
278 fd = open("/dev/urandom", O_RDONLY);
279 if (fd < 0)
280 goto out;
281 ret = -2;
282 if (read(fd, &seed, len) != len)
283 goto out;
284 srandom(seed);
285 ret = 1;
286 out:
287 if (fd >= 0)
288 close(fd);
289 if (ret > 0)
290 return;
291 PARA_EMERG_LOG("can not seed pseudo random generator (ret = %d)\n",
292 ret);
293 exit(EXIT_FAILURE);
294 }
295
296 uint32_t afs_socket_cookie;
297 int afs_socket;
298 static pid_t afs_pid;
299
300 static void init_afs(void)
301 {
302 int ret, afs_server_socket[2];
303
304 ret = socketpair(PF_UNIX, SOCK_DGRAM, 0, afs_server_socket);
305 if (ret < 0)
306 exit(EXIT_FAILURE);
307 afs_socket_cookie = para_random((uint32_t)-1);
308 afs_pid = fork();
309 if (afs_pid < 0)
310 exit(EXIT_FAILURE);
311 if (!afs_pid) { /* child (afs) */
312 close(afs_server_socket[0]);
313 afs_init(afs_socket_cookie, afs_server_socket[1]);
314 }
315 close(afs_server_socket[1]);
316 afs_socket = afs_server_socket[0];
317 ret = mark_fd_nonblock(afs_socket);
318 if (ret < 0)
319 exit(EXIT_FAILURE);
320 add_close_on_fork_list(afs_socket);
321 PARA_INFO_LOG("afs_socket: %d, afs_socket_cookie: %u\n", afs_socket,
322 (unsigned) afs_socket_cookie);
323 }
324
325
326 static unsigned do_inits(int argc, char **argv)
327 {
328 /* connector's address information */
329 int sockfd;
330
331 init_random_seed();
332 /* parse command line options */
333 server_cmdline_parser(argc, argv, &conf);
334 HANDLE_VERSION_FLAG("server", conf);
335 para_drop_privileges(conf.user_arg, conf.group_arg);
336 /* parse config file, open log and set defaults */
337 parse_config(0);
338 log_welcome("para_server", conf.loglevel_arg);
339 shm_init(); /* init mmd struct */
340 server_uptime(UPTIME_SET); /* reset server uptime */
341 init_user_list(user_list_file);
342 /* become daemon */
343 if (conf.daemon_given)
344 daemon_init();
345 PARA_NOTICE_LOG("%s", "initializing virtual streaming system\n");
346 afh_init();
347 vss_init();
348 mmd->server_pid = getpid();
349 setup_signal_handling();
350 init_afs();
351 mmd_lock();
352 /* init network socket */
353 PARA_NOTICE_LOG("%s", "initializing tcp command socket\n");
354 sockfd = init_network();
355 PARA_NOTICE_LOG("%s", "init complete\n");
356 return sockfd;
357 }
358
359 /*
360 * called when server gets SIGHUP or when client invokes hup command.
361 */
362 static void handle_sighup(void)
363 {
364 PARA_NOTICE_LOG("%s", "SIGHUP\n");
365 close_log(logfile); /* gets reopened if necessary by parse_config */
366 logfile = NULL;
367 parse_config(1); /* reopens log */
368 init_user_list(user_list_file); /* reload user list */
369 if (afs_pid)
370 kill(afs_pid, SIGHUP);
371 }
372
373 static void status_refresh(void)
374 {
375 static int prev_uptime = -1, prev_events = -1;
376 int uptime = server_uptime(UPTIME_GET), ret = 1;
377
378 if (prev_events != mmd->events)
379 goto out;
380 if (mmd->new_vss_status_flags != mmd->vss_status_flags)
381 goto out;
382 if (uptime / 60 != prev_uptime / 60)
383 goto out;
384 ret = 0;
385 out:
386 prev_uptime = uptime;
387 prev_events = mmd->events;
388 mmd->vss_status_flags = mmd->new_vss_status_flags;
389 if (ret) {
390 PARA_DEBUG_LOG("%d events, forcing status update\n",
391 mmd->events);
392 killpg(0, SIGUSR1);
393 }
394 }
395
396 /**
397 * the main function of para_server
398 *
399 * \param argc usual argument count
400 * \param argv usual argument vector
401 *
402 * \return EXIT_SUCCESS or EXIT_FAILURE
403 *
404 */
405 int main(int argc, char *argv[])
406 {
407 /* listen on sock_fd, new connection on new_fd */
408 int sockfd, new_fd;
409 struct sockaddr_in their_addr;
410 int i, max_fileno, ret;
411 pid_t chld_pid;
412 fd_set rfds, wfds;
413 struct timeval *timeout;
414
415 valid_fd_012();
416 sockfd = do_inits(argc, argv);
417 repeat:
418 FD_ZERO(&rfds);
419 FD_ZERO(&wfds);
420 max_fileno = -1;
421 /* check socket and signal pipe in any case */
422 para_fd_set(sockfd, &rfds, &max_fileno);
423 para_fd_set(signal_pipe, &rfds, &max_fileno);
424 timeout = vss_preselect(&rfds, &wfds, &max_fileno);
425 status_refresh();
426 for (i = 0; senders[i].name; i++) {
427 if (senders[i].status != SENDER_ON)
428 continue;
429 if (!senders[i].pre_select)
430 continue;
431 senders[i].pre_select(&max_fileno, &rfds, &wfds);
432 }
433 mmd_unlock();
434 ret = para_select(max_fileno + 1, &rfds, &wfds, timeout);
435 mmd_lock();
436 vss_post_select(&rfds, &wfds);
437 if (ret < 0)
438 goto repeat;
439 for (i = 0; senders[i].name; i++) {
440 if (senders[i].status != SENDER_ON)
441 continue;
442 if (!senders[i].post_select)
443 continue;
444 senders[i].post_select(&rfds, &wfds);
445 }
446 vss_send_chunk();
447 status_refresh();
448 if (FD_ISSET(signal_pipe, &rfds)) {
449 int sig;
450 pid_t pid;
451 sig = para_next_signal();
452 switch (sig) {
453 case SIGHUP:
454 handle_sighup();
455 break;
456 case SIGCHLD:
457 for (;;) {
458 ret = para_reap_child(&pid);
459 if (ret <= 0)
460 break;
461 if (pid != afs_pid)
462 continue;
463 PARA_EMERG_LOG("fatal: afs died\n");
464 goto genocide;
465 }
466 break;
467 /* die on sigint/sigterm. Kill all children too. */
468 case SIGINT:
469 case SIGTERM:
470 PARA_EMERG_LOG("terminating on signal %d\n", sig);
471 genocide:
472 kill(0, SIGTERM);
473 mutex_destroy(mmd_mutex);
474 shm_detach(mmd);
475 shm_destroy(mmd_shm_id);
476
477 exit(EXIT_FAILURE);
478 }
479 }
480 if (mmd->sender_cmd_data.cmd_num >= 0) {
481 int num = mmd->sender_cmd_data.cmd_num,
482 s = mmd->sender_cmd_data.sender_num;
483
484 if (senders[s].client_cmds[num])
485 senders[s].client_cmds[num](&mmd->sender_cmd_data);
486 mmd->sender_cmd_data.cmd_num = -1;
487 }
488 if (!FD_ISSET(sockfd, &rfds))
489 goto repeat;
490
491 new_fd = para_accept(sockfd, &their_addr, sizeof(struct sockaddr_in));
492 if (new_fd < 0)
493 goto repeat;
494 PARA_INFO_LOG("got connection from %s, forking\n",
495 inet_ntoa(their_addr.sin_addr));
496 mmd->num_connects++;
497 mmd->active_connections++;
498 random();
499 chld_pid = fork();
500 if (chld_pid < 0) {
501 PARA_CRIT_LOG("%s", "fork failed\n");
502 goto repeat;
503 }
504 if (chld_pid) {
505 close(new_fd);
506 /* parent keeps accepting connections */
507 goto repeat;
508 }
509 alarm(ALARM_TIMEOUT);
510 close_listed_fds();
511 close(sockfd); /* child doesn't need the listener */
512 /*
513 * put info on who we are serving into argv[0] to make
514 * client ip visible in top/ps
515 */
516 for (i = argc - 1; i >= 0; i--)
517 memset(argv[i], 0, strlen(argv[i]));
518 sprintf(argv[0], "para_server (serving %s)",
519 inet_ntoa(their_addr.sin_addr));
520 return handle_connect(new_fd, &their_addr);
521 }