2 * Thread handling stuff for Citadel server
4 * Copyright (c) 1987-2021 by the citadel.org team
6 * This program is open source software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License, version 3.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
18 #include <libcitadel.h>
19 #include "modules_init.h"
20 #include "serv_extensions.h"
21 #include "ctdl_module.h"
26 int num_workers = 0; /* Current number of worker threads */
27 int active_workers = 0; /* Number of ACTIVE worker threads */
28 pthread_key_t ThreadKey;
29 pthread_mutex_t Critters[MAX_SEMAPHORES]; /* Things needing locking */
30 struct thread_tsd masterTSD;
31 int server_shutting_down = 0; /* set to nonzero during shutdown */
32 pthread_mutex_t ThreadCountMutex;
34 void InitializeSemaphores(void)
38 /* Set up a bunch of semaphores to be used for critical sections */
39 for (i=0; i<MAX_SEMAPHORES; ++i) {
40 pthread_mutex_init(&Critters[i], NULL);
46 * Obtain a semaphore lock to begin a critical section.
47 * but only if no one else has one
49 int try_critical_section(int which_one)
51 /* For all types of critical sections except those listed here,
52 * ensure nobody ever tries to do a critical section within a
53 * transaction; this could lead to deadlock.
55 if ( (which_one != S_FLOORCACHE)
56 && (which_one != S_NETCONFIGS)
60 return (pthread_mutex_trylock(&Critters[which_one]));
65 * Obtain a semaphore lock to begin a critical section.
67 void begin_critical_section(int which_one)
69 /* For all types of critical sections except those listed here,
70 * ensure nobody ever tries to do a critical section within a
71 * transaction; this could lead to deadlock.
73 if ( (which_one != S_FLOORCACHE)
74 && (which_one != S_NETCONFIGS)
78 pthread_mutex_lock(&Critters[which_one]);
83 * Release a semaphore lock to end a critical section.
85 void end_critical_section(int which_one)
87 pthread_mutex_unlock(&Critters[which_one]);
92 * Return a pointer to our thread-specific (not session-specific) data.
94 struct thread_tsd *MyThread(void) {
95 struct thread_tsd *c = (struct thread_tsd *) pthread_getspecific(ThreadKey) ;
104 * Called by CtdlThreadCreate()
105 * We have to pass through here before starting our thread in order to create a set of data
106 * that is thread-specific rather than session-specific.
108 void *CTC_backend(void *supplied_start_routine)
110 struct thread_tsd *mytsd;
111 void *(*start_routine)(void*) = supplied_start_routine;
113 mytsd = (struct thread_tsd *) malloc(sizeof(struct thread_tsd));
114 memset(mytsd, 0, sizeof(struct thread_tsd));
115 pthread_setspecific(ThreadKey, (const void *) mytsd);
124 * Function to create a thread.
126 void CtdlThreadCreate(void *(*start_routine)(void*))
132 ret = pthread_attr_init(&attr);
133 ret = pthread_attr_setstacksize(&attr, THREADSTACKSIZE);
134 ret = pthread_create(&thread, &attr, CTC_backend, (void *)start_routine);
135 if (ret != 0) syslog(LOG_ERR, "pthread_create() : %m");
139 void InitializeMasterTSD(void) {
140 memset(&masterTSD, 0, sizeof(struct thread_tsd));
145 * Initialize the thread system
147 void go_threading(void) {
148 pthread_mutex_init(&ThreadCountMutex, NULL);
150 /* Second call to module init functions now that threading is up */
151 initialise_modules(1);
153 /* Begin with one worker thread. We will expand the pool if necessary */
154 CtdlThreadCreate(worker_thread);
156 /* The supervisor thread monitors worker threads and spawns more of them if it finds that
157 * they are all in use.
159 while (!server_shutting_down) {
160 if ((active_workers == num_workers) && (num_workers < CtdlGetConfigInt("c_max_workers"))) {
161 CtdlThreadCreate(worker_thread);
166 /* When we get to this point we are getting ready to shut down our Citadel server */
167 terminate_all_sessions(); /* close all client sockets */
168 CtdlShutdownServiceHooks(); /* close all listener sockets to prevent new connections */
169 PerformSessionHooks(EVT_SHUTDOWN); /* run any registered shutdown hooks */
171 /* We used to wait for all threads to exit. Fuck that. The only thing important is that the databases are
172 * cleanly unmounted. After that, exit the whole program.