2 * Empire - A multi-player, client/server Internet based war game.
3 * Copyright (C) 1986-2021, Dave Pare, Jeff Bailey, Thomas Ruschak,
4 * Ken Stevens, Steve McClure, Markus Armbruster
6 * Empire is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, either version 3 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
21 * See files README, COPYING and CREDITS in the root of the source
22 * tree for related information and legal notices. It is expected
23 * that future projects/authors will amend these files as needed.
27 * pthread.c: Interface from Empire threads to POSIX threads
29 * Known contributors to this file:
32 * Markus Armbruster, 2005-2012
33 * Ron Koenderink, 2007-2009
46 #include <sys/select.h>
49 #include "empthread.h"
51 #include "prototypes.h"
54 char *name; /* thread name */
55 void *ud; /* user data */
57 void (*ep)(void *); /* entry point */
58 pthread_t id; /* thread ID */
61 struct empth_rwlock_t {
62 /* Can't use pthread_rwlock_t, because it needn't prefer writers */
64 int nread; /* #active readers */
65 int nwrite; /* total #writers (active and waiting) */
66 pthread_cond_t can_read;
67 pthread_cond_t can_write;
70 /* Thread-specific data key */
71 static pthread_key_t ctx_key;
73 /* Flags that were passed to empth_init() */
74 static int empth_flags;
76 /* Pointer to thread context variable */
80 * Non-preemption mutex.
81 * Empire code outside this file is only executed while holding this
82 * mutex. This makes sure Empire code is never preempted by Empire
85 static pthread_mutex_t mtx_ctxsw;
87 static void empth_status(char *format, ...)
88 ATTRIBUTE((format (printf, 1, 2)));
89 static void empth_alarm(int sig);
92 empth_start(void *arg)
96 ctx->id = pthread_self();
97 pthread_setspecific(ctx_key, ctx);
98 pthread_mutex_lock(&mtx_ctxsw);
106 empth_status(char *format, ...)
109 static struct timeval startTime;
115 va_start(ap, format);
116 if (empth_flags & EMPTH_PRINT) {
117 if (startTime.tv_sec == 0)
118 gettimeofday(&startTime, 0);
119 gettimeofday(&tv, 0);
120 sec = tv.tv_sec - startTime.tv_sec;
121 msec = (tv.tv_usec - startTime.tv_usec) / 1000;
126 vsprintf(buf, format, ap);
128 printf("%d:%02d.%03d %17s: %s\n", sec / 60, sec % 60, msec / 10,
137 empth_init(void **ctx_ptr, int flags)
141 struct sigaction act;
146 empth_init_signals();
148 sigaddset(&set, SIGHUP);
149 sigaddset(&set, SIGINT);
150 sigaddset(&set, SIGTERM);
151 pthread_sigmask(SIG_BLOCK, &set, NULL);
153 sigemptyset(&act.sa_mask);
154 act.sa_handler = empth_alarm;
155 sigaction(SIGALRM, &act, NULL);
157 pthread_key_create(&ctx_key, NULL);
158 pthread_mutex_init(&mtx_ctxsw, NULL);
160 ctx = malloc(sizeof(empth_t));
162 logerror("pthread init failed: not enough memory");
168 ctx->id = pthread_self();
170 pthread_setspecific(ctx_key, ctx);
171 pthread_mutex_lock(&mtx_ctxsw);
177 empth_create(void (*entry)(void *), int size, int flags,
178 char *name, void *ud)
185 empth_status("creating new thread %s", name);
188 ctx = malloc(sizeof(empth_t));
190 logerror("not enough memory to create thread %s", name);
193 ctx->name = strdup(name);
198 eno = pthread_attr_init(&attr);
200 logerror("can not create thread attribute %s: %s",
201 name, strerror(eno));
204 if (size < PTHREAD_STACK_MIN)
205 size = PTHREAD_STACK_MIN;
206 pthread_attr_setstacksize(&attr, size);
207 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
209 eno = pthread_create(&t, &attr, empth_start, ctx);
211 logerror("can not create thread: %s: %s", name, strerror(eno));
214 empth_status("new thread ID is %ld", (long)t);
219 pthread_attr_destroy(&attr);
226 empth_restorectx(void)
230 ctx_ptr = pthread_getspecific(ctx_key);
231 *udata = ctx_ptr->ud;
233 empth_status("context restored");
239 return udata ? pthread_getspecific(ctx_key) : NULL;
243 empth_name(empth_t *thread)
249 empth_set_name(empth_t *thread, char *name)
253 thread->name = strdup(name);
259 empth_t *ctx = pthread_getspecific(ctx_key);
261 empth_status("empth_exit");
263 pthread_mutex_unlock(&mtx_ctxsw);
273 pthread_mutex_unlock(&mtx_ctxsw);
274 pthread_mutex_lock(&mtx_ctxsw);
279 empth_select(int fd, int flags, struct timeval *timeout)
288 if (CANT_HAPPEN(fd < 0 || fd >= FD_SETSIZE)) {
294 pthread_mutex_unlock(&mtx_ctxsw);
295 empth_status("select on %d for %d", fd, flags);
300 if (flags & EMPTH_FD_READ)
301 FD_SET(fd, &readmask);
302 if (flags & EMPTH_FD_WRITE)
303 FD_SET(fd, &writemask);
307 n = select(fd + 1, &readmask, &writemask, NULL, timeout ? &tv : NULL);
309 ctx = pthread_getspecific(ctx_key);
311 empth_status("select woken up");
313 } else if (errno == EINTR) {
314 empth_status("select broken by signal");
317 empth_status("select failed (%s)", strerror(errno));
321 empth_status("select timed out");
323 } else if (flags == EMPTH_FD_READ && FD_ISSET(fd, &readmask)) {
324 empth_status("input ready");
326 } else if (flags == EMPTH_FD_WRITE && FD_ISSET(fd, &writemask)) {
327 empth_status("output ready");
331 pthread_mutex_lock(&mtx_ctxsw);
340 * Nothing to do --- we handle this signal just to let
341 * empth_wakeup() interrupt system calls.
346 empth_wakeup(empth_t *a)
348 empth_status("waking up thread %s", a->name);
350 pthread_kill(a->id, SIGALRM);
354 empth_sleep(time_t until)
356 empth_t *ctx = pthread_getspecific(ctx_key);
362 pthread_mutex_unlock(&mtx_ctxsw);
365 tv.tv_sec = until >= now ? until - now : 0;
367 empth_status("going to sleep %ld sec", (long)tv.tv_sec);
368 res = select(0, NULL, NULL, NULL, &tv);
369 } while (res < 0 && !ctx->wakeup);
370 empth_status("sleep done. Waiting for lock");
371 pthread_mutex_lock(&mtx_ctxsw);
377 empth_wait_for_signal(void)
384 sigaddset(&set, SIGHUP);
385 sigaddset(&set, SIGINT);
386 sigaddset(&set, SIGTERM);
387 pthread_mutex_unlock(&mtx_ctxsw);
389 empth_status("waiting for signals");
390 err = sigwait(&set, &sig);
391 if (CANT_HAPPEN(err)) {
395 empth_status("got awaited signal %d", sig);
396 pthread_mutex_lock(&mtx_ctxsw);
403 empth_rwlock_create(char *name)
405 empth_rwlock_t *rwlock;
407 rwlock = malloc(sizeof(*rwlock));
411 if (pthread_cond_init(&rwlock->can_read, NULL) != 0
412 || pthread_cond_init(&rwlock->can_write, NULL) != 0) {
417 rwlock->name = strdup(name);
418 rwlock->nread = rwlock->nwrite = 0;
423 empth_rwlock_destroy(empth_rwlock_t *rwlock)
425 pthread_cond_destroy(&rwlock->can_read);
426 pthread_cond_destroy(&rwlock->can_write);
432 empth_rwlock_wrlock(empth_rwlock_t *rwlock)
434 empth_status("wrlock %s %d %d",
435 rwlock->name, rwlock->nread, rwlock->nwrite);
438 while (rwlock->nread != 0 || rwlock->nwrite != 1) {
439 empth_status("waiting for wrlock %s", rwlock->name);
440 pthread_cond_wait(&rwlock->can_write, &mtx_ctxsw);
441 empth_status("got wrlock %s %d %d",
442 rwlock->name, rwlock->nread, rwlock->nwrite);
448 empth_rwlock_rdlock(empth_rwlock_t *rwlock)
450 empth_status("rdlock %s %d %d",
451 rwlock->name, rwlock->nread, rwlock->nwrite);
453 while (rwlock->nwrite) {
454 empth_status("waiting for rdlock %s", rwlock->name);
455 pthread_cond_wait(&rwlock->can_read, &mtx_ctxsw);
456 empth_status("got rdlock %s %d %d",
457 rwlock->name, rwlock->nread, rwlock->nwrite);
464 empth_rwlock_unlock(empth_rwlock_t *rwlock)
466 if (CANT_HAPPEN(!rwlock->nread && !rwlock->nwrite))
468 if (rwlock->nread) { /* holding read lock */
469 if (!--rwlock->nread)
470 pthread_cond_signal(&rwlock->can_write);
473 pthread_cond_signal(&rwlock->can_write);
475 if (rwlock->nwrite == 0)
476 pthread_cond_broadcast(&rwlock->can_read);