/* * Empire - A multi-player, client/server Internet based war game. * Copyright (C) 1986-2008, Dave Pare, Jeff Bailey, Thomas Ruschak, * Ken Stevens, Steve McClure * * This program 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 * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * 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 * * --- * * See files README, COPYING and CREDITS in the root of the source * tree for related information and legal notices. It is expected * that future projects/authors will amend these files as needed. * * --- * * empthread.h: Definitions for Empire threading * * Known contributors to this file: * Sasha Mikheev * Doug Hay, 1998 * Steve McClure, 1998 * Markus Armbruster, 2005-2007 */ /* * This header defines Empire's abstract thread interface. There are * several concrete implementations. * * 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. */ #ifndef EMPTHREAD_H #define EMPTHREAD_H #include #ifdef EMPTH_LWP #include "lwp.h" /* Abstract data types */ /* empth_t * represents a thread. */ typedef struct lwpProc empth_t; /* empth_rwlock_t * represents a read-write lock */ typedef struct lwp_rwlock empth_rwlock_t; /* Flags for empth_select(): whether to sleep on input or output */ #define EMPTH_FD_READ LWP_FD_READ #define EMPTH_FD_WRITE LWP_FD_WRITE /* Flags for empth_init() and empth_create() */ /* Request debug prints */ #define EMPTH_PRINT LWP_PRINT /* Request stack checking */ #define EMPTH_STACKCHECK LWP_STACKCHECK #endif /* EMPTH_LWP */ #ifdef EMPTH_POSIX #define EMPTH_FD_READ 0x1 #define EMPTH_FD_WRITE 0x2 #define EMPTH_PRINT 0x1 #define EMPTH_STACKCHECK 0x2 typedef struct empth_t empth_t; typedef struct empth_rwlock_t empth_rwlock_t; #endif /* EMPTH_POSIX */ #ifdef EMPTH_W32 /* The Windows NT Threads */ #define EMPTH_FD_READ 0x1 #define EMPTH_FD_WRITE 0x2 #define EMPTH_PRINT 0x1 #define EMPTH_STACKCHECK 0x2 typedef struct loc_Thread empth_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. * Should return 0 on success, -1 on error, but currently always * returns 0. */ int empth_init(void **ctx, int flags); /* * Create a new thread. * 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 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(void (*entry)(void *), int size, int flags, char *name, void *ud); /* * Return the current thread. */ empth_t *empth_self(void); /* * Terminate the current thread. * The current thread should not be the thread that executed main(). * If it is, implementations may terminate the process rather than the * thread. * Never returns. */ void empth_exit(void); /* * Yield the processor. */ 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. * Naive use of this function almost always leads to resource leaks. * Terminating a thread that may hold locks is not a good idea. */ 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. * 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 * socket. Implementations should not rely on that. */ void empth_select(int fd, int flags); /* * Awaken THREAD if it is sleeping in empth_select() or empth_sleep(). * Note: This must 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. * Return 0 if it slept until that time. * Return -1 if woken up early, by empth_wakeup(). */ int empth_sleep(time_t until); /* * Wait for signal, return the signal number. */ int empth_wait_for_signal(void); /* * Create a read-write lock. * NAME is its name, it is used for debugging. * Return the reade-write lock, or NULL on error. */ empth_rwlock_t *empth_rwlock_create(char *name); /* * Destroy RWLOCK. */ void empth_rwlock_destroy(empth_rwlock_t *rwlock); /* * 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. * 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. */ void empth_rwlock_rdlock(empth_rwlock_t *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); /* * Stuff for implementations, not for clients. */ void empth_init_signals(void); #endif