/[LeafOK_CVS]/lbbs/src/net_server.c
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Revision 1.67 - (show annotations)
Wed Jun 25 02:49:20 2025 UTC (8 months, 3 weeks ago) by sysadm
Branch: MAIN
Changes since 1.66: +23 -5 lines
Content type: text/x-csrc
Use RW_lock to avoid conflict between menu reload of data loader process and main process in rare condition

1 /***************************************************************************
2 net_server.c - description
3 -------------------
4 Copyright : (C) 2004-2025 by Leaflet
5 Email : leaflet@leafok.com
6 ***************************************************************************/
7
8 /***************************************************************************
9 * *
10 * This program is free software; you can redistribute it and/or modify *
11 * it under the terms of the GNU General Public License as published by *
12 * the Free Software Foundation; either version 3 of the License, or *
13 * (at your option) any later version. *
14 * *
15 ***************************************************************************/
16
17 #include "bbs.h"
18 #include "bbs_main.h"
19 #include "common.h"
20 #include "database.h"
21 #include "file_loader.h"
22 #include "io.h"
23 #include "init.h"
24 #include "log.h"
25 #include "login.h"
26 #include "menu.h"
27 #include "net_server.h"
28 #include "section_list.h"
29 #include "section_list_loader.h"
30 #include <errno.h>
31 #include <fcntl.h>
32 #include <signal.h>
33 #include <stdlib.h>
34 #include <string.h>
35 #include <unistd.h>
36 #include <arpa/inet.h>
37 #include <libssh/callbacks.h>
38 #include <libssh/libssh.h>
39 #include <libssh/server.h>
40 #include <netinet/in.h>
41 #include <sys/epoll.h>
42 #include <sys/socket.h>
43 #include <sys/syscall.h>
44 #include <sys/types.h>
45 #include <sys/wait.h>
46 #include <systemd/sd-daemon.h>
47
48 struct process_sockaddr_t
49 {
50 pid_t pid;
51 in_addr_t s_addr;
52 };
53 typedef struct process_sockaddr_t PROCESS_SOCKADDR;
54
55 static PROCESS_SOCKADDR process_sockaddr_pool[MAX_CLIENT_LIMIT];
56
57 #define SSH_AUTH_MAX_DURATION (60 * 1000) // milliseconds
58
59 struct ssl_server_cb_data_t
60 {
61 int tries;
62 int error;
63 };
64
65 static int auth_password(ssh_session session, const char *user,
66 const char *password, void *userdata)
67 {
68 struct ssl_server_cb_data_t *p_data = userdata;
69 int ret;
70
71 if (strcmp(user, "guest") == 0)
72 {
73 ret = load_guest_info();
74 }
75 else
76 {
77 ret = check_user(user, password);
78 }
79
80 if (ret == 0)
81 {
82 return SSH_AUTH_SUCCESS;
83 }
84
85 if ((++(p_data->tries)) >= BBS_login_retry_times)
86 {
87 p_data->error = 1;
88 }
89
90 return SSH_AUTH_DENIED;
91 }
92
93 static int pty_request(ssh_session session, ssh_channel channel, const char *term,
94 int x, int y, int px, int py, void *userdata)
95 {
96 return 0;
97 }
98
99 static int shell_request(ssh_session session, ssh_channel channel, void *userdata)
100 {
101 return 0;
102 }
103
104 static struct ssh_channel_callbacks_struct channel_cb = {
105 .channel_pty_request_function = pty_request,
106 .channel_shell_request_function = shell_request};
107
108 static ssh_channel new_session_channel(ssh_session session, void *userdata)
109 {
110 if (SSH_channel != NULL)
111 {
112 return NULL;
113 }
114
115 SSH_channel = ssh_channel_new(session);
116 ssh_callbacks_init(&channel_cb);
117 ssh_set_channel_callbacks(SSH_channel, &channel_cb);
118
119 return SSH_channel;
120 }
121
122 static int fork_server(void)
123 {
124 ssh_event event;
125 int pid;
126 int i;
127 int ret;
128
129 struct ssl_server_cb_data_t cb_data = {
130 .tries = 0,
131 .error = 0,
132 };
133
134 struct ssh_server_callbacks_struct cb = {
135 .userdata = &cb_data,
136 .auth_password_function = auth_password,
137 .channel_open_request_session_function = new_session_channel,
138 };
139
140 pid = fork();
141
142 if (pid > 0) // Parent process
143 {
144 SYS_child_process_count++;
145 log_common("Child process (%d) start\n", pid);
146 return pid;
147 }
148 else if (pid < 0) // Error
149 {
150 log_error("fork() error (%d)\n", errno);
151 return -1;
152 }
153
154 // Child process
155
156 if (close(socket_server[0]) == -1 || close(socket_server[1]) == -1)
157 {
158 log_error("Close server socket failed\n");
159 }
160
161 SSH_session = ssh_new();
162
163 if (SSH_v2)
164 {
165 if (ssh_bind_accept_fd(sshbind, SSH_session, socket_client) != SSH_OK)
166 {
167 log_error("ssh_bind_accept_fd() error: %s\n", ssh_get_error(SSH_session));
168 goto cleanup;
169 }
170
171 ssh_bind_free(sshbind);
172
173 ssh_callbacks_init(&cb);
174 ssh_set_server_callbacks(SSH_session, &cb);
175
176 if (ssh_handle_key_exchange(SSH_session))
177 {
178 log_error("ssh_handle_key_exchange() error: %s\n", ssh_get_error(SSH_session));
179 goto cleanup;
180 }
181 ssh_set_auth_methods(SSH_session, SSH_AUTH_METHOD_PASSWORD);
182
183 event = ssh_event_new();
184 ssh_event_add_session(event, SSH_session);
185
186 for (i = 0; i < SSH_AUTH_MAX_DURATION && !SYS_server_exit && !cb_data.error && SSH_channel == NULL; i += 100)
187 {
188 ret = ssh_event_dopoll(event, 100); // 0.1 second
189 if (ret == SSH_ERROR)
190 {
191 log_error("ssh_event_dopoll() error: %s\n", ssh_get_error(SSH_session));
192 goto cleanup;
193 }
194 }
195
196 if (cb_data.error)
197 {
198 log_error("SSH auth error, tried %d times\n", cb_data.tries);
199 goto cleanup;
200 }
201 }
202
203 // Redirect Input
204 close(STDIN_FILENO);
205 if (dup2(socket_client, STDIN_FILENO) == -1)
206 {
207 log_error("Redirect stdin to client socket failed\n");
208 goto cleanup;
209 }
210
211 // Redirect Output
212 close(STDOUT_FILENO);
213 if (dup2(socket_client, STDOUT_FILENO) == -1)
214 {
215 log_error("Redirect stdout to client socket failed\n");
216 goto cleanup;
217 }
218
219 SYS_child_process_count = 0;
220
221 bbs_main();
222
223 cleanup:
224 // Child process exit
225 SYS_server_exit = 1;
226
227 if (SSH_v2)
228 {
229 ssh_channel_free(SSH_channel);
230 ssh_disconnect(SSH_session);
231 }
232 else if (close(socket_client) == -1)
233 {
234 log_error("Close client socket failed\n");
235 }
236
237 ssh_free(SSH_session);
238 ssh_finalize();
239
240 // Close Input and Output for client
241 close(STDIN_FILENO);
242 close(STDOUT_FILENO);
243
244 log_common("Process exit normally\n");
245 log_end();
246
247 _exit(0);
248
249 return 0;
250 }
251
252 int net_server(const char *hostaddr, in_port_t port[])
253 {
254 unsigned int addrlen;
255 int ret;
256 int flags[2];
257 struct sockaddr_in sin;
258 struct epoll_event ev, events[MAX_EVENTS];
259 int nfds, epollfd;
260 siginfo_t siginfo;
261 int sd_notify_stopping = 0;
262 MENU_SET bbs_menu_new;
263 int i, j;
264 pid_t pid;
265 int ssh_log_level = SSH_LOG_NOLOG;
266
267 ssh_init();
268
269 sshbind = ssh_bind_new();
270
271 if (ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_BINDADDR, hostaddr) < 0 ||
272 ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_BINDPORT, &port) < 0 ||
273 ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_HOSTKEY, SSH_HOST_KEYFILE) < 0 ||
274 ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_HOSTKEY_ALGORITHMS, "ssh-rsa,rsa-sha2-512,rsa-sha2-256") < 0 ||
275 ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_LOG_VERBOSITY, &ssh_log_level) < 0)
276 {
277 log_error("Error setting SSH bind options: %s\n", ssh_get_error(sshbind));
278 ssh_bind_free(sshbind);
279 return -1;
280 }
281
282 epollfd = epoll_create1(0);
283 if (epollfd < 0)
284 {
285 log_error("epoll_create1() error (%d)\n", errno);
286 return -1;
287 }
288
289 // Server socket
290 for (i = 0; i < 2; i++)
291 {
292 socket_server[i] = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
293
294 if (socket_server[i] < 0)
295 {
296 log_error("Create socket_server error (%d)\n", errno);
297 return -1;
298 }
299
300 sin.sin_family = AF_INET;
301 sin.sin_addr.s_addr = (hostaddr[0] != '\0' ? inet_addr(hostaddr) : INADDR_ANY);
302 sin.sin_port = htons(port[i]);
303
304 // Reuse address and port
305 flags[i] = 1;
306 if (setsockopt(socket_server[i], SOL_SOCKET, SO_REUSEADDR, &flags[i], sizeof(flags[i])) < 0)
307 {
308 log_error("setsockopt SO_REUSEADDR error (%d)\n", errno);
309 }
310 if (setsockopt(socket_server[i], SOL_SOCKET, SO_REUSEPORT, &flags[i], sizeof(flags[i])) < 0)
311 {
312 log_error("setsockopt SO_REUSEPORT error (%d)\n", errno);
313 }
314
315 if (bind(socket_server[i], (struct sockaddr *)&sin, sizeof(sin)) < 0)
316 {
317 log_error("Bind address %s:%u error (%d)\n",
318 inet_ntoa(sin.sin_addr), ntohs(sin.sin_port), errno);
319 return -1;
320 }
321
322 if (listen(socket_server[i], 10) < 0)
323 {
324 log_error("Telnet socket listen error (%d)\n", errno);
325 return -1;
326 }
327
328 log_common("Listening at %s:%u\n", inet_ntoa(sin.sin_addr), ntohs(sin.sin_port));
329
330 ev.events = EPOLLIN;
331 ev.data.fd = socket_server[i];
332 if (epoll_ctl(epollfd, EPOLL_CTL_ADD, socket_server[i], &ev) == -1)
333 {
334 log_error("epoll_ctl(socket_server[%d]) error (%d)\n", i, errno);
335 if (close(epollfd) < 0)
336 {
337 log_error("close(epoll) error (%d)\n");
338 }
339 return -1;
340 }
341
342 flags[i] = fcntl(socket_server[i], F_GETFL, 0);
343 fcntl(socket_server[i], F_SETFL, flags[i] | O_NONBLOCK);
344 }
345
346 // Startup complete
347 sd_notifyf(0, "READY=1\n"
348 "STATUS=Listening at %s:%d (Telnet) and %s:%d (SSH2)\n"
349 "MAINPID=%d",
350 hostaddr, port[0], hostaddr, port[1], getpid());
351
352 while (!SYS_server_exit || SYS_child_process_count > 0)
353 {
354 if (SYS_server_exit && !sd_notify_stopping)
355 {
356 sd_notify(0, "STOPPING=1");
357 sd_notify_stopping = 1;
358 }
359
360 while ((SYS_child_exit || SYS_server_exit) && SYS_child_process_count > 0)
361 {
362 SYS_child_exit = 0;
363
364 siginfo.si_pid = 0;
365 ret = waitid(P_ALL, 0, &siginfo, WEXITED | WNOHANG);
366 if (ret == 0 && siginfo.si_pid > 0)
367 {
368 SYS_child_exit = 1; // Retry waitid
369
370 SYS_child_process_count--;
371 log_common("Child process (%d) exited\n", siginfo.si_pid);
372
373 if (siginfo.si_pid != section_list_loader_pid)
374 {
375 i = 0;
376 for (; i < BBS_max_client; i++)
377 {
378 if (process_sockaddr_pool[i].pid == siginfo.si_pid)
379 {
380 process_sockaddr_pool[i].pid = 0;
381 break;
382 }
383 }
384 if (i >= BBS_max_client)
385 {
386 log_error("Child process (%d) not found in process sockaddr pool\n", siginfo.si_pid);
387 }
388 }
389 }
390 else if (ret == 0)
391 {
392 break;
393 }
394 else if (ret < 0)
395 {
396 log_error("Error in waitid: %d\n", errno);
397 break;
398 }
399 }
400
401 if (SYS_server_exit && !SYS_child_exit && SYS_child_process_count > 0)
402 {
403 log_common("Notify %d child process to exit\n", SYS_child_process_count);
404 if (kill(0, SIGTERM) < 0)
405 {
406 log_error("Send SIGTERM signal failed (%d)\n", errno);
407 }
408
409 sd_notifyf(0, "STATUS=Waiting for %d child process to exit", SYS_child_process_count);
410 }
411
412 if (SYS_conf_reload && !SYS_server_exit)
413 {
414 SYS_conf_reload = 0;
415 sd_notify(0, "RELOADING=1");
416
417 // Reload configuration
418 if (load_conf(CONF_BBSD) < 0)
419 {
420 log_error("Reload conf failed\n");
421 }
422
423 // acquire rw lock of all sections to avoid conflict with menu reload in data loader process
424 ret = section_list_rw_lock(NULL);
425 if (ret < 0)
426 {
427 log_error("section_list_rw_lock(NULL) error\n");
428 }
429 else
430 {
431 if (load_menu(&bbs_menu_new, CONF_MENU) < 0)
432 {
433 unload_menu(&bbs_menu_new);
434 log_error("Reload menu failed\n");
435 }
436 else
437 {
438 unload_menu(&bbs_menu);
439 memcpy(&bbs_menu, &bbs_menu_new, sizeof(bbs_menu_new));
440 log_common("Reload menu successfully\n");
441 }
442
443 // release rw lock of all sections
444 ret = section_list_rw_unlock(NULL);
445 if (ret < 0)
446 {
447 log_error("section_list_rw_unlock(NULL) error\n");
448 }
449 }
450
451 sd_notify(0, "READY=1");
452 }
453
454 if (SYS_data_file_reload && !SYS_server_exit)
455 {
456 SYS_data_file_reload = 0;
457 sd_notify(0, "RELOADING=1");
458
459 for (int i = 0; i < data_files_load_startup_count; i++)
460 {
461 if (load_file(data_files_load_startup[i]) < 0)
462 {
463 log_error("load_file_mmap(%s) error\n", data_files_load_startup[i]);
464 }
465 }
466
467 log_common("Reload data files successfully\n");
468 sd_notify(0, "READY=1");
469 }
470
471 if (SYS_section_list_reload && !SYS_server_exit)
472 {
473 SYS_section_list_reload = 0;
474
475 if (section_list_loader_reload() < 0)
476 {
477 log_error("section_list_loader_reload() failed\n");
478 }
479 }
480
481 nfds = epoll_wait(epollfd, events, MAX_EVENTS, 100); // 0.1 second
482
483 if (nfds < 0)
484 {
485 if (errno != EINTR)
486 {
487 log_error("epoll_wait() error (%d)\n", errno);
488 break;
489 }
490 continue;
491 }
492
493 // Stop accept new connection on exit
494 if (SYS_server_exit)
495 {
496 continue;
497 }
498
499 for (int i = 0; i < nfds; i++)
500 {
501 if (events[i].data.fd == socket_server[0] || events[i].data.fd == socket_server[1])
502 {
503 SSH_v2 = (events[i].data.fd == socket_server[1] ? 1 : 0);
504
505 while (!SYS_server_exit) // Accept all incoming connections until error
506 {
507 addrlen = sizeof(sin);
508 socket_client = accept(socket_server[SSH_v2], (struct sockaddr *)&sin, &addrlen);
509 if (socket_client < 0)
510 {
511 if (errno == EAGAIN || errno == EWOULDBLOCK)
512 {
513 break;
514 }
515 else if (errno == EINTR)
516 {
517 continue;
518 }
519 else
520 {
521 log_error("accept(socket_server) error (%d)\n", errno);
522 break;
523 }
524 }
525
526 strncpy(hostaddr_client, inet_ntoa(sin.sin_addr), sizeof(hostaddr_client) - 1);
527 hostaddr_client[sizeof(hostaddr_client) - 1] = '\0';
528
529 port_client = ntohs(sin.sin_port);
530
531 log_common("Accept %s connection from %s:%d\n", (SSH_v2 ? "SSH" : "telnet"), hostaddr_client, port_client);
532
533 if (SYS_child_process_count - 1 < BBS_max_client)
534 {
535 j = 0;
536 for (i = 0; i < BBS_max_client; i++)
537 {
538 if (process_sockaddr_pool[i].pid != 0 && process_sockaddr_pool[i].s_addr == sin.sin_addr.s_addr)
539 {
540 j++;
541 if (j >= BBS_max_client_per_ip)
542 {
543 log_common("Too many client connections (%d) from %s\n", j, hostaddr_client);
544 break;
545 }
546 }
547 }
548
549 if (j < BBS_max_client_per_ip)
550 {
551 if ((pid = fork_server()) < 0)
552 {
553 log_error("fork_server() error\n");
554 }
555 else if (pid > 0)
556 {
557 i = 0;
558 for (; i < BBS_max_client; i++)
559 {
560 if (process_sockaddr_pool[i].pid == 0)
561 {
562 break;
563 }
564 }
565
566 if (i >= BBS_max_client)
567 {
568 log_error("Process sockaddr pool depleted\n");
569 }
570 else
571 {
572 process_sockaddr_pool[i].pid = pid;
573 process_sockaddr_pool[i].s_addr = sin.sin_addr.s_addr;
574 }
575 }
576 }
577 }
578 else
579 {
580 log_error("Rejected client connection over limit (%d)\n", SYS_child_process_count - 1);
581 }
582
583 if (close(socket_client) == -1)
584 {
585 log_error("close(socket_lient) error (%d)\n", errno);
586 }
587 }
588 }
589 }
590 }
591
592 if (close(epollfd) < 0)
593 {
594 log_error("close(epoll) error (%d)\n");
595 }
596
597 for (i = 0; i < 2; i++)
598 {
599 fcntl(socket_server[i], F_SETFL, flags[i]);
600
601 if (close(socket_server[i]) == -1)
602 {
603 log_error("Close server socket failed\n");
604 }
605 }
606
607 ssh_bind_free(sshbind);
608 ssh_finalize();
609
610 return 0;
611 }

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