/[LeafOK_CVS]/lbbs/src/net_server.c
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Contents of /lbbs/src/net_server.c

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Revision 1.59 - (show annotations)
Mon Jun 16 14:32:25 2025 UTC (9 months ago) by sysadm
Branch: MAIN
Changes since 1.58: +2 -0 lines
Content type: text/x-csrc
Avoid duplicate receiving SIGTERM to cause process termination

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 #define _XOPEN_SOURCE 500
18 #define _POSIX_C_SOURCE 200809L
19 #define _GNU_SOURCE
20
21 #include "net_server.h"
22 #include "common.h"
23 #include "bbs_main.h"
24 #include "bbs.h"
25 #include "log.h"
26 #include "io.h"
27 #include "init.h"
28 #include "menu.h"
29 #include "database.h"
30 #include "login.h"
31 #include "file_loader.h"
32 #include "section_list_loader.h"
33 #include <errno.h>
34 #include <fcntl.h>
35 #include <string.h>
36 #include <signal.h>
37 #include <stdlib.h>
38 #include <unistd.h>
39 #include <sys/syscall.h>
40 #include <sys/socket.h>
41 #include <sys/wait.h>
42 #include <sys/epoll.h>
43 #include <arpa/inet.h>
44 #include <netinet/in.h>
45 #include <systemd/sd-daemon.h>
46 #include <libssh/libssh.h>
47 #include <libssh/server.h>
48 #include <libssh/callbacks.h>
49
50 struct process_sockaddr_t
51 {
52 pid_t pid;
53 in_addr_t s_addr;
54 };
55 typedef struct process_sockaddr_t PROCESS_SOCKADDR;
56
57 static PROCESS_SOCKADDR process_sockaddr_pool[MAX_CLIENT_LIMIT];
58
59 #define SSH_AUTH_MAX_DURATION (60 * 1000) // milliseconds
60
61 struct ssl_server_cb_data_t
62 {
63 int tries;
64 int error;
65 };
66
67 static int auth_password(ssh_session session, const char *user,
68 const char *password, void *userdata)
69 {
70 struct ssl_server_cb_data_t *p_data = userdata;
71 int ret;
72
73 if (strcmp(user, "guest") == 0)
74 {
75 ret = load_guest_info();
76 }
77 else
78 {
79 ret = check_user(user, password);
80 }
81
82 if (ret == 0)
83 {
84 return SSH_AUTH_SUCCESS;
85 }
86
87 if ((++(p_data->tries)) >= BBS_login_retry_times)
88 {
89 p_data->error = 1;
90 }
91
92 return SSH_AUTH_DENIED;
93 }
94
95 static int pty_request(ssh_session session, ssh_channel channel, const char *term,
96 int x, int y, int px, int py, void *userdata)
97 {
98 return 0;
99 }
100
101 static int shell_request(ssh_session session, ssh_channel channel, void *userdata)
102 {
103 return 0;
104 }
105
106 static struct ssh_channel_callbacks_struct channel_cb = {
107 .channel_pty_request_function = pty_request,
108 .channel_shell_request_function = shell_request};
109
110 static ssh_channel new_session_channel(ssh_session session, void *userdata)
111 {
112 if (SSH_channel != NULL)
113 {
114 return NULL;
115 }
116
117 SSH_channel = ssh_channel_new(session);
118 ssh_callbacks_init(&channel_cb);
119 ssh_set_channel_callbacks(SSH_channel, &channel_cb);
120
121 return SSH_channel;
122 }
123
124 static int fork_server(void)
125 {
126 ssh_event event;
127 int pid;
128 int i;
129 int ret;
130
131 struct ssl_server_cb_data_t cb_data = {
132 .tries = 0,
133 .error = 0,
134 };
135
136 struct ssh_server_callbacks_struct cb = {
137 .userdata = &cb_data,
138 .auth_password_function = auth_password,
139 .channel_open_request_session_function = new_session_channel,
140 };
141
142 pid = fork();
143
144 if (pid > 0) // Parent process
145 {
146 SYS_child_process_count++;
147 log_common("Child process (%d) start\n", pid);
148 return pid;
149 }
150 else if (pid < 0) // Error
151 {
152 log_error("fork() error (%d)\n", errno);
153 return -1;
154 }
155
156 // Child process
157
158 if (close(socket_server[0]) == -1 || close(socket_server[1]) == -1)
159 {
160 log_error("Close server socket failed\n");
161 }
162
163 SSH_session = ssh_new();
164
165 if (SSH_v2)
166 {
167 if (ssh_bind_accept_fd(sshbind, SSH_session, socket_client) != SSH_OK)
168 {
169 log_error("ssh_bind_accept_fd() error: %s\n", ssh_get_error(SSH_session));
170 goto cleanup;
171 }
172
173 ssh_bind_free(sshbind);
174
175 ssh_callbacks_init(&cb);
176 ssh_set_server_callbacks(SSH_session, &cb);
177
178 if (ssh_handle_key_exchange(SSH_session))
179 {
180 log_error("ssh_handle_key_exchange() error: %s\n", ssh_get_error(SSH_session));
181 goto cleanup;
182 }
183 ssh_set_auth_methods(SSH_session, SSH_AUTH_METHOD_PASSWORD);
184
185 event = ssh_event_new();
186 ssh_event_add_session(event, SSH_session);
187
188 for (i = 0; i < SSH_AUTH_MAX_DURATION && !SYS_server_exit && !cb_data.error && SSH_channel == NULL; i += 100)
189 {
190 ret = ssh_event_dopoll(event, 100); // 0.1 second
191 if (ret == SSH_ERROR)
192 {
193 log_error("ssh_event_dopoll() error: %s\n", ssh_get_error(SSH_session));
194 goto cleanup;
195 }
196 }
197
198 if (cb_data.error)
199 {
200 log_error("SSH auth error, tried %d times\n", cb_data.tries);
201 goto cleanup;
202 }
203 }
204
205 // Redirect Input
206 close(STDIN_FILENO);
207 if (dup2(socket_client, STDIN_FILENO) == -1)
208 {
209 log_error("Redirect stdin to client socket failed\n");
210 goto cleanup;
211 }
212
213 // Redirect Output
214 close(STDOUT_FILENO);
215 if (dup2(socket_client, STDOUT_FILENO) == -1)
216 {
217 log_error("Redirect stdout to client socket failed\n");
218 goto cleanup;
219 }
220
221 SYS_child_process_count = 0;
222
223 bbs_main();
224
225 cleanup:
226 // Child process exit
227 SYS_server_exit = 1;
228
229 if (SSH_v2)
230 {
231 ssh_channel_free(SSH_channel);
232 ssh_disconnect(SSH_session);
233 }
234 else if (close(socket_client) == -1)
235 {
236 log_error("Close client socket failed\n");
237 }
238
239 ssh_free(SSH_session);
240 ssh_finalize();
241
242 // Close Input and Output for client
243 close(STDIN_FILENO);
244 close(STDOUT_FILENO);
245
246 log_common("Process exit normally\n");
247 log_end();
248
249 _exit(0);
250
251 return 0;
252 }
253
254 int net_server(const char *hostaddr, in_port_t port[])
255 {
256 unsigned int addrlen;
257 int ret;
258 int flags[2];
259 struct sockaddr_in sin;
260 struct epoll_event ev, events[MAX_EVENTS];
261 int nfds, epollfd;
262 siginfo_t siginfo;
263 int sd_notify_stopping = 0;
264 MENU_SET *p_bbs_menu_new;
265 int i, j;
266 pid_t pid;
267 int ssh_log_level = SSH_LOG_NOLOG;
268
269 ssh_init();
270
271 sshbind = ssh_bind_new();
272
273 if (ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_BINDADDR, hostaddr) < 0 ||
274 ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_BINDPORT, &port) < 0 ||
275 ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_HOSTKEY, SSH_HOST_KEYFILE) < 0 ||
276 ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_LOG_VERBOSITY, &ssh_log_level) < 0)
277 {
278 log_error("Error setting SSH bind options: %s\n", ssh_get_error(sshbind));
279 ssh_bind_free(sshbind);
280 return -1;
281 }
282
283 epollfd = epoll_create1(0);
284 if (epollfd < 0)
285 {
286 log_error("epoll_create1() error (%d)\n", errno);
287 return -1;
288 }
289
290 // Server socket
291 for (i = 0; i < 2; i++)
292 {
293 socket_server[i] = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
294
295 if (socket_server[i] < 0)
296 {
297 log_error("Create socket_server error (%d)\n", errno);
298 return -1;
299 }
300
301 sin.sin_family = AF_INET;
302 sin.sin_addr.s_addr = (hostaddr[0] != '\0' ? inet_addr(hostaddr) : INADDR_ANY);
303 sin.sin_port = htons(port[i]);
304
305 // Reuse address and port
306 flags[i] = 1;
307 if (setsockopt(socket_server[i], SOL_SOCKET, SO_REUSEADDR, &flags[i], sizeof(flags[i])) < 0)
308 {
309 log_error("setsockopt SO_REUSEADDR error (%d)\n", errno);
310 }
311 if (setsockopt(socket_server[i], SOL_SOCKET, SO_REUSEPORT, &flags[i], sizeof(flags[i])) < 0)
312 {
313 log_error("setsockopt SO_REUSEPORT error (%d)\n", errno);
314 }
315
316 if (bind(socket_server[i], (struct sockaddr *)&sin, sizeof(sin)) < 0)
317 {
318 log_error("Bind address %s:%u error (%d)\n",
319 inet_ntoa(sin.sin_addr), ntohs(sin.sin_port), errno);
320 return -1;
321 }
322
323 if (listen(socket_server[i], 10) < 0)
324 {
325 log_error("Telnet socket listen error (%d)\n", errno);
326 return -1;
327 }
328
329 log_common("Listening at %s:%u\n", inet_ntoa(sin.sin_addr), ntohs(sin.sin_port));
330
331 ev.events = EPOLLIN;
332 ev.data.fd = socket_server[i];
333 if (epoll_ctl(epollfd, EPOLL_CTL_ADD, socket_server[i], &ev) == -1)
334 {
335 log_error("epoll_ctl(socket_server[%d]) error (%d)\n", i, errno);
336 if (close(epollfd) < 0)
337 {
338 log_error("close(epoll) error (%d)\n");
339 }
340 return -1;
341 }
342
343 flags[i] = fcntl(socket_server[i], F_GETFL, 0);
344 fcntl(socket_server[i], F_SETFL, flags[i] | O_NONBLOCK);
345 }
346
347 // Startup complete
348 sd_notifyf(0, "READY=1\n"
349 "STATUS=Listening at %s:%d (Telnet) and %s:%d (SSH2)\n"
350 "MAINPID=%d",
351 hostaddr, port[0], hostaddr, port[1], getpid());
352
353 while (!SYS_server_exit || SYS_child_process_count > 0)
354 {
355 if (SYS_server_exit && !sd_notify_stopping)
356 {
357 signal(SIGHUP, SIG_IGN);
358
359 sd_notify(0, "STOPPING=1");
360 sd_notify_stopping = 1;
361 }
362
363 while ((SYS_child_exit || SYS_server_exit) && SYS_child_process_count > 0)
364 {
365 SYS_child_exit = 0;
366
367 siginfo.si_pid = 0;
368 ret = waitid(P_ALL, 0, &siginfo, WEXITED | WNOHANG);
369 if (ret == 0 && siginfo.si_pid > 0)
370 {
371 SYS_child_exit = 1; // Retry waitid
372
373 SYS_child_process_count--;
374 log_common("Child process (%d) exited\n", siginfo.si_pid);
375
376 if (siginfo.si_pid != section_list_loader_pid)
377 {
378 i = 0;
379 for (; i < BBS_max_client; i++)
380 {
381 if (process_sockaddr_pool[i].pid == siginfo.si_pid)
382 {
383 process_sockaddr_pool[i].pid = 0;
384 break;
385 }
386 }
387 if (i >= BBS_max_client)
388 {
389 log_error("Child process (%d) not found in process sockaddr pool\n", siginfo.si_pid);
390 }
391 }
392 }
393 else if (ret == 0)
394 {
395 break;
396 }
397 else if (ret < 0)
398 {
399 log_error("Error in waitid: %d\n", errno);
400 break;
401 }
402 }
403
404 if (SYS_server_exit && !SYS_child_exit && SYS_child_process_count > 0)
405 {
406 log_common("Notify %d child process to exit\n", SYS_child_process_count);
407 if (kill(0, SIGTERM) < 0)
408 {
409 log_error("Send SIGTERM signal failed (%d)\n", errno);
410 }
411
412 sd_notifyf(0, "STATUS=Waiting for %d child process to exit", SYS_child_process_count);
413 }
414
415 if (SYS_conf_reload && !SYS_server_exit)
416 {
417 SYS_conf_reload = 0;
418 sd_notify(0, "RELOADING=1");
419
420 // Reload configuration
421 if (load_conf(CONF_BBSD) < 0)
422 {
423 log_error("Reload conf failed\n");
424 }
425
426 p_bbs_menu_new = calloc(1, sizeof(MENU_SET));
427 if (p_bbs_menu_new == NULL)
428 {
429 log_error("OOM: calloc(MENU_SET)\n");
430 }
431 else if (load_menu(p_bbs_menu_new, CONF_MENU) < 0)
432 {
433 unload_menu(p_bbs_menu_new);
434 free(p_bbs_menu_new);
435 p_bbs_menu_new = NULL;
436
437 log_error("Reload menu failed\n");
438 }
439 else
440 {
441 unload_menu(p_bbs_menu);
442 free(p_bbs_menu);
443
444 p_bbs_menu = p_bbs_menu_new;
445 p_bbs_menu_new = NULL;
446
447 log_common("Reload menu successfully\n");
448 }
449
450 sd_notify(0, "READY=1");
451 }
452
453 if (SYS_data_file_reload && !SYS_server_exit)
454 {
455 SYS_data_file_reload = 0;
456 sd_notify(0, "RELOADING=1");
457
458 for (int i = 0; i < data_files_load_startup_count; i++)
459 {
460 if (load_file(data_files_load_startup[i]) < 0)
461 {
462 log_error("load_file_mmap(%s) error\n", data_files_load_startup[i]);
463 }
464 }
465
466 log_common("Reload data files successfully\n");
467 sd_notify(0, "READY=1");
468 }
469
470 if (SYS_section_list_reload && !SYS_server_exit)
471 {
472 SYS_section_list_reload = 0;
473
474 if (section_list_loader_reload() < 0)
475 {
476 log_error("ksection_list_loader_reload() failed\n");
477 }
478 }
479
480 nfds = epoll_wait(epollfd, events, MAX_EVENTS, 100); // 0.1 second
481
482 if (nfds < 0)
483 {
484 if (errno != EINTR)
485 {
486 log_error("epoll_wait() error (%d)\n", errno);
487 break;
488 }
489 continue;
490 }
491
492 // Stop accept new connection on exit
493 if (SYS_server_exit)
494 {
495 continue;
496 }
497
498 for (int i = 0; i < nfds; i++)
499 {
500 if (events[i].data.fd == socket_server[0] || events[i].data.fd == socket_server[1])
501 {
502 SSH_v2 = (events[i].data.fd == socket_server[1] ? 1 : 0);
503
504 while (!SYS_server_exit) // Accept all incoming connections until error
505 {
506 addrlen = sizeof(sin);
507 socket_client = accept(socket_server[SSH_v2], (struct sockaddr *)&sin, &addrlen);
508 if (socket_client < 0)
509 {
510 if (errno == EAGAIN || errno == EWOULDBLOCK)
511 {
512 break;
513 }
514 else if (errno == EINTR)
515 {
516 continue;
517 }
518 else
519 {
520 log_error("accept(socket_server) error (%d)\n", errno);
521 break;
522 }
523 }
524
525 strncpy(hostaddr_client, inet_ntoa(sin.sin_addr), sizeof(hostaddr_client) - 1);
526 hostaddr_client[sizeof(hostaddr_client) - 1] = '\0';
527
528 port_client = ntohs(sin.sin_port);
529
530 log_common("Accept %sconnection from %s:%d\n", (SSH_v2 ? "" : "SSH2 "), hostaddr_client, port_client);
531
532 if (SYS_child_process_count - 1 < BBS_max_client)
533 {
534 j = 0;
535 for (i = 0; i < BBS_max_client; i++)
536 {
537 if (process_sockaddr_pool[i].pid != 0 && process_sockaddr_pool[i].s_addr == sin.sin_addr.s_addr)
538 {
539 j++;
540 if (j >= BBS_max_client_per_ip)
541 {
542 log_common("Too many client connections (%d) from %s\n", j, hostaddr_client);
543 break;
544 }
545 }
546 }
547
548 if (j < BBS_max_client_per_ip)
549 {
550 if ((pid = fork_server()) < 0)
551 {
552 log_error("fork_server() error\n");
553 }
554 else if (pid > 0)
555 {
556 i = 0;
557 for (; i < BBS_max_client; i++)
558 {
559 if (process_sockaddr_pool[i].pid == 0)
560 {
561 break;
562 }
563 }
564
565 if (i >= BBS_max_client)
566 {
567 log_error("Process sockaddr pool depleted\n");
568 }
569 else
570 {
571 process_sockaddr_pool[i].pid = pid;
572 process_sockaddr_pool[i].s_addr = sin.sin_addr.s_addr;
573 }
574 }
575 }
576 }
577 else
578 {
579 log_error("Rejected client connection over limit (%d)\n", SYS_child_process_count - 1);
580 }
581
582 if (close(socket_client) == -1)
583 {
584 log_error("close(socket_lient) error (%d)\n", errno);
585 }
586 }
587 }
588 }
589 }
590
591 if (close(epollfd) < 0)
592 {
593 log_error("close(epoll) error (%d)\n");
594 }
595
596 for (i = 0; i < 2; i++)
597 {
598 fcntl(socket_server[i], F_SETFL, flags[i]);
599
600 if (close(socket_server[i]) == -1)
601 {
602 log_error("Close server socket failed\n");
603 }
604 }
605
606 ssh_bind_free(sshbind);
607 ssh_finalize();
608
609 return 0;
610 }

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