/*
* Empire - A multi-player, client/server Internet based war game.
- * Copyright (C) 1986-2007, Dave Pare, Jeff Bailey, Thomas Ruschak,
- * Ken Stevens, Steve McClure
+ * Copyright (C) 1986-2021, Dave Pare, Jeff Bailey, Thomas Ruschak,
+ * Ken Stevens, Steve McClure, Markus Armbruster
*
- * This program is free software; you can redistribute it and/or modify
+ * Empire is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
+ * the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* ---
*
* ---
*
* empthread.h: Definitions for Empire threading
- *
+ *
* Known contributors to this file:
* Sasha Mikheev
* Doug Hay, 1998
* Steve McClure, 1998
- * Markus Armbruster, 2005-2007
+ * Markus Armbruster, 2005-2012
+ * Ron Koenderink, 2005-2009
*/
/*
*
* Empire threads are non-preemptive, i.e. they run until they
* voluntarily yield the processor. The thread scheduler then picks
- * one of the runnable threads with the highest priority. Priorities
- * are static. Empire code relies on these properties heavily. The
- * most common form of yielding the processor is sleeping for some
- * event to happen.
+ * one of the runnable threads. The most common form of yielding the
+ * processor is sleeping for some event to happen.
*/
#ifndef EMPTHREAD_H
#define EMPTHREAD_H
+#include <sys/time.h>
#include <time.h>
-/* thread priorities */
-enum {
- PP_MAIN = 7,
- PP_UPDATE = 6,
- PP_SHUTDOWN = 5,
- PP_SCHED = 4,
- PP_TIMESTAMP = 2,
- PP_PLAYER = 3,
- PP_ACCEPT = 3,
- PP_KILLIDLE = 2
-};
-
#ifdef EMPTH_LWP
#include "lwp.h"
/* Abstract data types */
-/* empth_t * represents a thread. */
+/* A thread. */
typedef struct lwpProc empth_t;
-/* empth_sem_t * represents a semaphore */
-typedef struct lwpSem empth_sem_t;
-
-/* empth_rwlock_t * represents a read-write lock */
+/* A read-write lock, perferring writers */
typedef struct lwp_rwlock empth_rwlock_t;
/* Flags for empth_select(): whether to sleep on input or output */
#define EMPTH_STACKCHECK 0x2
typedef struct empth_t empth_t;
-typedef struct empth_sem_t empth_sem_t;
typedef struct empth_rwlock_t empth_rwlock_t;
#endif /* EMPTH_POSIX */
#define EMPTH_STACKCHECK 0x2
typedef struct loc_Thread empth_t;
-typedef struct loc_Sem_t empth_sem_t;
-typedef struct loc_RWLock_t empth_rwlock_t;
+typedef struct loc_RWLock empth_rwlock_t;
void empth_request_shutdown(void);
#endif /* EMPTH_W32 */
/*
* Initialize thread package.
- * CTX points to a thread context variable; see empth_create().
- * FLAGS request optional features.
+ * @ctx points to a thread context variable; see empth_create().
+ * @flags request optional features.
* Should return 0 on success, -1 on error, but currently always
* returns 0.
*/
/*
* Create a new thread.
- * PRIO is the scheduling priority.
- * ENTRY is the entry point. It will be called with argument UD.
- * Thread stack is at least SIZE bytes.
- * FLAGS should be the same as were passed to empth_init(), or zero.
- * NAME is the threads name, and DESC its description. These are used
- * for logging and debugging.
- * UD is the value to pass to ENTRY. It is also assigned to the
+ * @entry is the entry point. It will be called with argument @ud.
+ * If it returns, the thread terminates as if it called empth_exit().
+ * Thread stack is at least @size bytes.
+ * @flags should be the same as were passed to empth_init(), or zero.
+ * @name is the thread's name, it is used for logging and debugging.
+ * @ud is the value to pass to @entry. It is also assigned to the
* context variable defined with empth_init() whenever the thread gets
* scheduled.
* Yield the processor.
* Return the thread, or NULL on error.
*/
-empth_t *empth_create(int prio, void (*entry)(void *),
- int size, int flags, char *name, char *desc, void *ud);
+empth_t *empth_create(void (*entry)(void *),
+ int size, int flags, char *name, void *ud);
/*
- * Return the current thread.
+ * Return the current thread, NULL before empth_init().
+ * This is the only function that may be called before empth_init().
*/
empth_t *empth_self(void);
+/*
+ * Return @thread's name.
+ */
+char *empth_name(empth_t *thread);
+
+/*
+ * Set @thread's name to @name.
+ */
+void empth_set_name(empth_t *thread, char *name);
+
/*
* Terminate the current thread.
* The current thread should not be the thread that executed main().
void empth_yield(void);
/*
- * Terminate THREAD.
- * THREAD will not be scheduled again. Instead, it will terminate as
- * if it executed empth_exit(). It is unspecified when exactly that
- * happens.
- * THREAD must not be the current thread.
- */
-void empth_terminate(empth_t *thread);
-
-/*
- * Put current thread to sleep until file descriptor FD is ready for I/O.
- * If FLAGS & EMPTH_FD_READ, wake up if FD is ready for input.
- * If FLAGS & EMPTH_FD_WRITE, wake up if FD is ready for output.
+ * Put current thread to sleep until file descriptor @fd is ready for I/O.
+ * If @flags & EMPTH_FD_READ, wake up if @fd is ready for input.
+ * If @flags & EMPTH_FD_WRITE, wake up if @fd is ready for output.
* At most one thread may sleep on the same file descriptor.
- * Note: Currently, Empire sleeps only on network I/O, i.e. FD is a
+ * @timeout, if non-null, limits the sleep time.
+ * Return one when the @fd is ready, zero on timeout or early wakeup by
+ * empth_wakeup(), -1 on error with errno set.
+ * Note: Currently, Empire sleeps only on network I/O, i.e. @fd is a
* socket. Implementations should not rely on that.
*/
-void empth_select(int fd, int flags);
+int empth_select(int fd, int flags, struct timeval *timeout);
/*
- * Awaken THREAD if it is sleeping in empth_select().
- * Note: This must not awaken threads sleeping in other functions.
+ * Awaken @thread if it is sleeping in empth_select() or empth_sleep().
+ * This does not awaken threads sleeping in other functions.
+ * Does not yield the processor.
*/
void empth_wakeup(empth_t *thread);
/*
- * Put current thread to sleep until the time is UNTIL.
- * May sleep somehwat longer, but never shorter.
+ * Put current thread to sleep until the time is @until.
+ * Return 0 if it slept until that time.
+ * Return -1 if woken up early, by empth_wakeup().
*/
-void empth_sleep(time_t until);
+int empth_sleep(time_t until);
/*
- * Wait for signal, return the signal number
+ * Put current thread to sleep until SIGHUP, SIGINT or SIGTERM is received.
+ * Return the signal number.
*/
int empth_wait_for_signal(void);
-/*
- * Create a semaphore.
- * NAME is its name, it is used for debugging.
- * COUNT is the initial count value of the semaphore, it must not be
- * negative.
- * Return the semaphore, or NULL on error.
- */
-empth_sem_t *empth_sem_create(char *name, int count);
-
-/*
- * Signal SEM.
- * Increase SEM's count. If threads are sleeping on it, wake up
- * exactly one of them. If that thread has a higher priority, yield
- * the processor.
- * This semaphore operation is often called `down' or `V' otherwhere.
- */
-void empth_sem_signal(empth_sem_t *sem);
-
-/*
- * Wait for SEM.
- * If SEM has a zero count, put current thread to sleep until
- * empth_sem_signal() awakens it. SEM will have non-zero value then.
- * Decrement SEM's count.
- * This semaphore operation is often called `up' or `P' otherwhere.
- */
-void empth_sem_wait(empth_sem_t *sem);
-
/*
* Create a read-write lock.
- * NAME is its name, it is used for debugging.
- * Return the reade-write lock, or NULL on error.
+ * @name is its name, it is used for debugging.
+ * Return the read-write lock, or NULL on error.
*/
empth_rwlock_t *empth_rwlock_create(char *name);
/*
- * Destroy RWLOCK.
+ * Destroy @rwlock.
*/
void empth_rwlock_destroy(empth_rwlock_t *rwlock);
/*
- * Lock RWLOCK for writing.
+ * Lock @rwlock for writing.
* A read-write lock can be locked for writing only when it is
* unlocked. If this is not the case, put the current thread to sleep
* until it is.
void empth_rwlock_wrlock(empth_rwlock_t *rwlock);
/*
- * Lock RWLOCK for reading.
+ * Lock @rwlock for reading.
* A read-write lock can be locked for reading only when it is not
- * locked for writing. If this is not the case, put the current
- * thread to sleep until it is. Must not starve writers, and may
- * sleep to avoid that.
+ * locked for writing, and no other thread is attempting to lock it
+ * for writing. If this is not the case, put the current thread to
+ * sleep until it is.
*/
void empth_rwlock_rdlock(empth_rwlock_t *rwlock);
/*
- * Unlock read-write lock RWLOCK.
- * The current thread must hold RWLOCK.
+ * Unlock read-write lock @rwlock.
+ * The current thread must hold @rwlock.
* Wake up threads that can now lock it.
*/
void empth_rwlock_unlock(empth_rwlock_t *rwlock);
projects / empserver / blobdiff