xref: /qemu/util/qemu-thread-win32.c (revision 96215036f47403438c7c7869b7cd419bd7a11f82)
1 /*
2  * Win32 implementation for mutex/cond/thread functions
3  *
4  * Copyright Red Hat, Inc. 2010
5  *
6  * Author:
7  *  Paolo Bonzini <pbonzini@redhat.com>
8  *
9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
10  * See the COPYING file in the top-level directory.
11  *
12  */
13 
14 #include "qemu/osdep.h"
15 #include "qemu/thread.h"
16 #include "qemu/notify.h"
17 #include "qemu-thread-common.h"
18 #include <process.h>
19 
20 static bool name_threads;
21 
22 typedef HRESULT (WINAPI *pSetThreadDescription) (HANDLE hThread,
23                                                  PCWSTR lpThreadDescription);
24 static pSetThreadDescription SetThreadDescriptionFunc;
25 static HMODULE kernel32_module;
26 
load_set_thread_description(void)27 static bool load_set_thread_description(void)
28 {
29     static gsize _init_once = 0;
30 
31     if (g_once_init_enter(&_init_once)) {
32         kernel32_module = LoadLibrary("kernel32.dll");
33         if (kernel32_module) {
34             SetThreadDescriptionFunc =
35                 (pSetThreadDescription)GetProcAddress(kernel32_module,
36                                                       "SetThreadDescription");
37             if (!SetThreadDescriptionFunc) {
38                 FreeLibrary(kernel32_module);
39             }
40         }
41         g_once_init_leave(&_init_once, 1);
42     }
43 
44     return !!SetThreadDescriptionFunc;
45 }
46 
qemu_thread_naming(bool enable)47 void qemu_thread_naming(bool enable)
48 {
49     name_threads = enable;
50 
51     if (enable && !load_set_thread_description()) {
52         fprintf(stderr, "qemu: thread naming not supported on this host\n");
53         name_threads = false;
54     }
55 }
56 
error_exit(int err,const char * msg)57 static void error_exit(int err, const char *msg)
58 {
59     char *pstr;
60 
61     FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ALLOCATE_BUFFER,
62                   NULL, err, 0, (LPTSTR)&pstr, 2, NULL);
63     fprintf(stderr, "qemu: %s: %s\n", msg, pstr);
64     LocalFree(pstr);
65     abort();
66 }
67 
qemu_mutex_init(QemuMutex * mutex)68 void qemu_mutex_init(QemuMutex *mutex)
69 {
70     InitializeSRWLock(&mutex->lock);
71     qemu_mutex_post_init(mutex);
72 }
73 
qemu_mutex_destroy(QemuMutex * mutex)74 void qemu_mutex_destroy(QemuMutex *mutex)
75 {
76     assert(mutex->initialized);
77     mutex->initialized = false;
78     InitializeSRWLock(&mutex->lock);
79 }
80 
qemu_mutex_lock_impl(QemuMutex * mutex,const char * file,const int line)81 void qemu_mutex_lock_impl(QemuMutex *mutex, const char *file, const int line)
82 {
83     assert(mutex->initialized);
84     qemu_mutex_pre_lock(mutex, file, line);
85     AcquireSRWLockExclusive(&mutex->lock);
86     qemu_mutex_post_lock(mutex, file, line);
87 }
88 
qemu_mutex_trylock_impl(QemuMutex * mutex,const char * file,const int line)89 int qemu_mutex_trylock_impl(QemuMutex *mutex, const char *file, const int line)
90 {
91     int owned;
92 
93     assert(mutex->initialized);
94     owned = TryAcquireSRWLockExclusive(&mutex->lock);
95     if (owned) {
96         qemu_mutex_post_lock(mutex, file, line);
97         return 0;
98     }
99     return -EBUSY;
100 }
101 
qemu_mutex_unlock_impl(QemuMutex * mutex,const char * file,const int line)102 void qemu_mutex_unlock_impl(QemuMutex *mutex, const char *file, const int line)
103 {
104     assert(mutex->initialized);
105     qemu_mutex_pre_unlock(mutex, file, line);
106     ReleaseSRWLockExclusive(&mutex->lock);
107 }
108 
qemu_rec_mutex_init(QemuRecMutex * mutex)109 void qemu_rec_mutex_init(QemuRecMutex *mutex)
110 {
111     InitializeCriticalSection(&mutex->lock);
112     mutex->initialized = true;
113 }
114 
qemu_rec_mutex_destroy(QemuRecMutex * mutex)115 void qemu_rec_mutex_destroy(QemuRecMutex *mutex)
116 {
117     assert(mutex->initialized);
118     mutex->initialized = false;
119     DeleteCriticalSection(&mutex->lock);
120 }
121 
qemu_rec_mutex_lock_impl(QemuRecMutex * mutex,const char * file,int line)122 void qemu_rec_mutex_lock_impl(QemuRecMutex *mutex, const char *file, int line)
123 {
124     assert(mutex->initialized);
125     EnterCriticalSection(&mutex->lock);
126 }
127 
qemu_rec_mutex_trylock_impl(QemuRecMutex * mutex,const char * file,int line)128 int qemu_rec_mutex_trylock_impl(QemuRecMutex *mutex, const char *file, int line)
129 {
130     assert(mutex->initialized);
131     return !TryEnterCriticalSection(&mutex->lock);
132 }
133 
qemu_rec_mutex_unlock_impl(QemuRecMutex * mutex,const char * file,int line)134 void qemu_rec_mutex_unlock_impl(QemuRecMutex *mutex, const char *file, int line)
135 {
136     assert(mutex->initialized);
137     LeaveCriticalSection(&mutex->lock);
138 }
139 
qemu_cond_init(QemuCond * cond)140 void qemu_cond_init(QemuCond *cond)
141 {
142     memset(cond, 0, sizeof(*cond));
143     InitializeConditionVariable(&cond->var);
144     cond->initialized = true;
145 }
146 
qemu_cond_destroy(QemuCond * cond)147 void qemu_cond_destroy(QemuCond *cond)
148 {
149     assert(cond->initialized);
150     cond->initialized = false;
151     InitializeConditionVariable(&cond->var);
152 }
153 
qemu_cond_signal(QemuCond * cond)154 void qemu_cond_signal(QemuCond *cond)
155 {
156     assert(cond->initialized);
157     WakeConditionVariable(&cond->var);
158 }
159 
qemu_cond_broadcast(QemuCond * cond)160 void qemu_cond_broadcast(QemuCond *cond)
161 {
162     assert(cond->initialized);
163     WakeAllConditionVariable(&cond->var);
164 }
165 
qemu_cond_wait_impl(QemuCond * cond,QemuMutex * mutex,const char * file,const int line)166 void qemu_cond_wait_impl(QemuCond *cond, QemuMutex *mutex, const char *file, const int line)
167 {
168     assert(cond->initialized);
169     qemu_mutex_pre_unlock(mutex, file, line);
170     SleepConditionVariableSRW(&cond->var, &mutex->lock, INFINITE, 0);
171     qemu_mutex_post_lock(mutex, file, line);
172 }
173 
qemu_cond_timedwait_impl(QemuCond * cond,QemuMutex * mutex,int ms,const char * file,const int line)174 bool qemu_cond_timedwait_impl(QemuCond *cond, QemuMutex *mutex, int ms,
175                               const char *file, const int line)
176 {
177     int rc = 0;
178 
179     assert(cond->initialized);
180     trace_qemu_mutex_unlock(mutex, file, line);
181     if (!SleepConditionVariableSRW(&cond->var, &mutex->lock, ms, 0)) {
182         rc = GetLastError();
183     }
184     trace_qemu_mutex_locked(mutex, file, line);
185     if (rc && rc != ERROR_TIMEOUT) {
186         error_exit(rc, __func__);
187     }
188     return rc != ERROR_TIMEOUT;
189 }
190 
qemu_sem_init(QemuSemaphore * sem,int init)191 void qemu_sem_init(QemuSemaphore *sem, int init)
192 {
193     /* Manual reset.  */
194     sem->sema = CreateSemaphore(NULL, init, LONG_MAX, NULL);
195     sem->initialized = true;
196 }
197 
qemu_sem_destroy(QemuSemaphore * sem)198 void qemu_sem_destroy(QemuSemaphore *sem)
199 {
200     assert(sem->initialized);
201     sem->initialized = false;
202     CloseHandle(sem->sema);
203 }
204 
qemu_sem_post(QemuSemaphore * sem)205 void qemu_sem_post(QemuSemaphore *sem)
206 {
207     assert(sem->initialized);
208     ReleaseSemaphore(sem->sema, 1, NULL);
209 }
210 
qemu_sem_timedwait(QemuSemaphore * sem,int ms)211 int qemu_sem_timedwait(QemuSemaphore *sem, int ms)
212 {
213     int rc;
214 
215     assert(sem->initialized);
216     rc = WaitForSingleObject(sem->sema, ms);
217     if (rc == WAIT_OBJECT_0) {
218         return 0;
219     }
220     if (rc != WAIT_TIMEOUT) {
221         error_exit(GetLastError(), __func__);
222     }
223     return -1;
224 }
225 
qemu_sem_wait(QemuSemaphore * sem)226 void qemu_sem_wait(QemuSemaphore *sem)
227 {
228     assert(sem->initialized);
229     if (WaitForSingleObject(sem->sema, INFINITE) != WAIT_OBJECT_0) {
230         error_exit(GetLastError(), __func__);
231     }
232 }
233 
234 struct QemuThreadData {
235     /* Passed to win32_start_routine.  */
236     void             *(*start_routine)(void *);
237     void             *arg;
238     short             mode;
239     NotifierList      exit;
240 
241     /* Only used for joinable threads. */
242     bool              exited;
243     void             *ret;
244     CRITICAL_SECTION  cs;
245 };
246 
247 static bool atexit_registered;
248 static NotifierList main_thread_exit;
249 
250 static __thread QemuThreadData *qemu_thread_data;
251 
run_main_thread_exit(void)252 static void run_main_thread_exit(void)
253 {
254     notifier_list_notify(&main_thread_exit, NULL);
255 }
256 
qemu_thread_atexit_add(Notifier * notifier)257 void qemu_thread_atexit_add(Notifier *notifier)
258 {
259     if (!qemu_thread_data) {
260         if (!atexit_registered) {
261             atexit_registered = true;
262             atexit(run_main_thread_exit);
263         }
264         notifier_list_add(&main_thread_exit, notifier);
265     } else {
266         notifier_list_add(&qemu_thread_data->exit, notifier);
267     }
268 }
269 
qemu_thread_atexit_remove(Notifier * notifier)270 void qemu_thread_atexit_remove(Notifier *notifier)
271 {
272     notifier_remove(notifier);
273 }
274 
win32_start_routine(void * arg)275 static unsigned __stdcall win32_start_routine(void *arg)
276 {
277     QemuThreadData *data = (QemuThreadData *) arg;
278     void *(*start_routine)(void *) = data->start_routine;
279     void *thread_arg = data->arg;
280 
281     qemu_thread_data = data;
282     qemu_thread_exit(start_routine(thread_arg));
283     abort();
284 }
285 
qemu_thread_exit(void * arg)286 void qemu_thread_exit(void *arg)
287 {
288     QemuThreadData *data = qemu_thread_data;
289 
290     notifier_list_notify(&data->exit, NULL);
291     if (data->mode == QEMU_THREAD_JOINABLE) {
292         data->ret = arg;
293         EnterCriticalSection(&data->cs);
294         data->exited = true;
295         LeaveCriticalSection(&data->cs);
296     } else {
297         g_free(data);
298     }
299     _endthreadex(0);
300 }
301 
qemu_thread_join(QemuThread * thread)302 void *qemu_thread_join(QemuThread *thread)
303 {
304     QemuThreadData *data;
305     void *ret;
306     HANDLE handle;
307 
308     data = thread->data;
309     if (data->mode == QEMU_THREAD_DETACHED) {
310         return NULL;
311     }
312 
313     /*
314      * Because multiple copies of the QemuThread can exist via
315      * qemu_thread_get_self, we need to store a value that cannot
316      * leak there.  The simplest, non racy way is to store the TID,
317      * discard the handle that _beginthreadex gives back, and
318      * get another copy of the handle here.
319      */
320     handle = qemu_thread_get_handle(thread);
321     if (handle) {
322         WaitForSingleObject(handle, INFINITE);
323         CloseHandle(handle);
324     }
325     ret = data->ret;
326     DeleteCriticalSection(&data->cs);
327     g_free(data);
328     return ret;
329 }
330 
set_thread_description(HANDLE h,const char * name)331 static bool set_thread_description(HANDLE h, const char *name)
332 {
333     HRESULT hr;
334     g_autofree wchar_t *namew = NULL;
335 
336     if (!load_set_thread_description()) {
337         return false;
338     }
339 
340     namew = g_utf8_to_utf16(name, -1, NULL, NULL, NULL);
341     if (!namew) {
342         return false;
343     }
344 
345     hr = SetThreadDescriptionFunc(h, namew);
346 
347     return SUCCEEDED(hr);
348 }
349 
qemu_thread_create(QemuThread * thread,const char * name,void * (* start_routine)(void *),void * arg,int mode)350 void qemu_thread_create(QemuThread *thread, const char *name,
351                        void *(*start_routine)(void *),
352                        void *arg, int mode)
353 {
354     HANDLE hThread;
355     struct QemuThreadData *data;
356 
357     data = g_malloc(sizeof *data);
358     data->start_routine = start_routine;
359     data->arg = arg;
360     data->mode = mode;
361     data->exited = false;
362     notifier_list_init(&data->exit);
363 
364     if (data->mode != QEMU_THREAD_DETACHED) {
365         InitializeCriticalSection(&data->cs);
366     }
367 
368     hThread = (HANDLE) _beginthreadex(NULL, 0, win32_start_routine,
369                                       data, 0, &thread->tid);
370     if (!hThread) {
371         error_exit(GetLastError(), __func__);
372     }
373     if (name_threads && name && !set_thread_description(hThread, name)) {
374         fprintf(stderr, "qemu: failed to set thread description: %s\n", name);
375     }
376     CloseHandle(hThread);
377 
378     thread->data = data;
379 }
380 
qemu_thread_set_affinity(QemuThread * thread,unsigned long * host_cpus,unsigned long nbits)381 int qemu_thread_set_affinity(QemuThread *thread, unsigned long *host_cpus,
382                              unsigned long nbits)
383 {
384     return -ENOSYS;
385 }
386 
qemu_thread_get_affinity(QemuThread * thread,unsigned long ** host_cpus,unsigned long * nbits)387 int qemu_thread_get_affinity(QemuThread *thread, unsigned long **host_cpus,
388                              unsigned long *nbits)
389 {
390     return -ENOSYS;
391 }
392 
qemu_thread_get_self(QemuThread * thread)393 void qemu_thread_get_self(QemuThread *thread)
394 {
395     thread->data = qemu_thread_data;
396     thread->tid = GetCurrentThreadId();
397 }
398 
qemu_thread_get_handle(QemuThread * thread)399 HANDLE qemu_thread_get_handle(QemuThread *thread)
400 {
401     QemuThreadData *data;
402     HANDLE handle;
403 
404     data = thread->data;
405     if (data->mode == QEMU_THREAD_DETACHED) {
406         return NULL;
407     }
408 
409     EnterCriticalSection(&data->cs);
410     if (!data->exited) {
411         handle = OpenThread(SYNCHRONIZE | THREAD_SUSPEND_RESUME |
412                             THREAD_SET_CONTEXT, FALSE, thread->tid);
413     } else {
414         handle = NULL;
415     }
416     LeaveCriticalSection(&data->cs);
417     return handle;
418 }
419 
qemu_thread_is_self(QemuThread * thread)420 bool qemu_thread_is_self(QemuThread *thread)
421 {
422     return GetCurrentThreadId() == thread->tid;
423 }
424