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.
13 #include <libcitadel.h>
14 #include "modules_init.h"
15 #include "serv_extensions.h"
16 #include "ctdl_module.h"
21 int num_workers = 0; /* Current number of worker threads */
22 int active_workers = 0; /* Number of ACTIVE worker threads */
23 pthread_key_t ThreadKey;
24 pthread_mutex_t Critters[MAX_SEMAPHORES]; /* Things needing locking */
25 struct thread_tsd masterTSD;
26 int server_shutting_down = 0; /* set to nonzero during shutdown */
27 pthread_mutex_t ThreadCountMutex;
29 void InitializeSemaphores(void)
33 /* Set up a bunch of semaphores to be used for critical sections */
34 for (i=0; i<MAX_SEMAPHORES; ++i) {
35 pthread_mutex_init(&Critters[i], NULL);
41 * Obtain a semaphore lock to begin a critical section.
42 * but only if no one else has one
44 int try_critical_section(int which_one)
46 /* For all types of critical sections except those listed here,
47 * ensure nobody ever tries to do a critical section within a
48 * transaction; this could lead to deadlock.
50 if ( (which_one != S_FLOORCACHE)
51 && (which_one != S_NETCONFIGS)
55 return (pthread_mutex_trylock(&Critters[which_one]));
60 * Obtain a semaphore lock to begin a critical section.
62 void begin_critical_section(int which_one)
64 /* For all types of critical sections except those listed here,
65 * ensure nobody ever tries to do a critical section within a
66 * transaction; this could lead to deadlock.
68 if ( (which_one != S_FLOORCACHE)
69 && (which_one != S_NETCONFIGS)
73 pthread_mutex_lock(&Critters[which_one]);
78 * Release a semaphore lock to end a critical section.
80 void end_critical_section(int which_one)
82 pthread_mutex_unlock(&Critters[which_one]);
87 * Return a pointer to our thread-specific (not session-specific) data.
89 struct thread_tsd *MyThread(void) {
90 struct thread_tsd *c = (struct thread_tsd *) pthread_getspecific(ThreadKey) ;
99 * Called by CtdlThreadCreate()
100 * We have to pass through here before starting our thread in order to create a set of data
101 * that is thread-specific rather than session-specific.
103 void *CTC_backend(void *supplied_start_routine)
105 struct thread_tsd *mytsd;
106 void *(*start_routine)(void*) = supplied_start_routine;
108 mytsd = (struct thread_tsd *) malloc(sizeof(struct thread_tsd));
109 memset(mytsd, 0, sizeof(struct thread_tsd));
110 pthread_setspecific(ThreadKey, (const void *) mytsd);
119 * Function to create a thread.
121 void CtdlThreadCreate(void *(*start_routine)(void*))
127 ret = pthread_attr_init(&attr);
128 ret = pthread_attr_setstacksize(&attr, THREADSTACKSIZE);
129 ret = pthread_create(&thread, &attr, CTC_backend, (void *)start_routine);
130 if (ret != 0) syslog(LOG_ERR, "pthread_create() : %m");
134 void InitializeMasterTSD(void) {
135 memset(&masterTSD, 0, sizeof(struct thread_tsd));
140 * Initialize the thread system
142 void go_threading(void) {
143 pthread_mutex_init(&ThreadCountMutex, NULL);
145 /* Second call to module init functions now that threading is up */
146 initialize_modules(1);
148 /* Begin with one worker thread. We will expand the pool if necessary */
149 CtdlThreadCreate(worker_thread);
151 /* The supervisor thread monitors worker threads and spawns more of them if it finds that
152 * they are all in use.
154 while (!server_shutting_down) {
155 if ((active_workers == num_workers) && (num_workers < CtdlGetConfigInt("c_max_workers"))) {
156 CtdlThreadCreate(worker_thread);
161 /* When we get to this point we are getting ready to shut down our Citadel server */
162 terminate_all_sessions(); /* close all client sockets */
163 CtdlShutdownServiceHooks(); /* close all listener sockets to prevent new connections */
164 PerformSessionHooks(EVT_SHUTDOWN); /* run any registered shutdown hooks */
166 /* We used to wait for all threads to exit. Fuck that. The only thing important is that the databases are
167 * cleanly unmounted. After that, exit the whole program.