mingw-w64-libraries/winpthreads/src/mutex.c - mingw-w64 - Git at Google

 /*
    Copyright (c) 2011, 2014 mingw-w64 project
    Copyright (c) 2015 Intel Corporation

    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
    to deal in the Software without restriction, including without limitation
    the rights to use, copy, modify, merge, publish, distribute, sublicense,
    and/or sell copies of the Software, and to permit persons to whom the
    Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in
    all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
    DEALINGS IN THE SOFTWARE.
 */

 #include <windows.h>
 #include <stdio.h>
 #include <malloc.h>
 #include <stdbool.h>
 #include "pthread.h"
 #include "misc.h"

 typedef enum {
   Unlocked,        /* Not locked. */
   Locked,          /* Locked but without waiters. */
   Waiting,         /* Locked, may have waiters. */
 } mutex_state_t;

 typedef enum {
   Normal,
   Errorcheck,
   Recursive,
 } mutex_type_t;

 /* The heap-allocated part of a mutex. */
 typedef struct {
   mutex_state_t state;
   mutex_type_t type;
   HANDLE event;       /* Auto-reset event, or NULL if not yet allocated. */
   unsigned rec_lock;  /* For recursive mutexes, the number of times the
                          mutex has been locked in excess by the same thread. */
   volatile DWORD owner;  /* For recursive and error-checking mutexes, the
                             ID of the owning thread if the mutex is locked. */
 } mutex_impl_t;

 /* Whether a mutex is still a static initializer (not a pointer to
    a mutex_impl_t). */
 static bool
 is_static_initializer(pthread_mutex_t m)
 {
   return (uintptr_t)m >= (uintptr_t)-3;
 }

 /* Create and return the implementation part of a mutex from a static
    initialiser. Return NULL on out-of-memory error. */
 static WINPTHREADS_ATTRIBUTE((noinline)) mutex_impl_t *
 mutex_impl_init(pthread_mutex_t *m, mutex_impl_t *mi)
 {
   mutex_impl_t *new_mi = malloc(sizeof(mutex_impl_t));
   if (new_mi == NULL)
     return NULL;
   new_mi->state = Unlocked;
   new_mi->type = (mi == PTHREAD_RECURSIVE_MUTEX_INITIALIZER ? Recursive
                   : mi == PTHREAD_ERRORCHECK_MUTEX_INITIALIZER ? Errorcheck
                   : Normal);
   new_mi->event = NULL;
   new_mi->rec_lock = 0;
   new_mi->owner = (DWORD)-1;
   if (__sync_bool_compare_and_swap(m, mi, new_mi)) {
     return new_mi;
   } else {
     /* Someone created the struct before us. */
     free(new_mi);
     return *m;
   }
 }

 #define likely(cond) __builtin_expect((cond) != 0, 1)
 #define unlikely(cond) __builtin_expect((cond) != 0, 0)

 /* Return the implementation part of a mutex, creating it if necessary.
    Return NULL on out-of-memory error. */
 static inline mutex_impl_t *
 mutex_impl(pthread_mutex_t *m)
 {
   mutex_impl_t *mi = *m;
   if (is_static_initializer(mi)) {
     return mutex_impl_init(m, mi);
   } else {
     /* mi cannot be null here; avoid a test in the fast path. */
     if (mi == NULL)
       __builtin_unreachable();
     return mi;
   }
 }

 /* Lock a mutex. Give up after 'timeout' ms (with ETIMEDOUT),
    or never if timeout=INFINITE. */
 static inline int
 pthread_mutex_lock_intern (pthread_mutex_t *m, DWORD timeout)
 {
   mutex_impl_t *mi = mutex_impl(m);
   if (mi == NULL)
     return ENOMEM;

   mutex_state_t old_state = __sync_lock_test_and_set(&mi->state, Locked);
   if (unlikely(old_state != Unlocked)) {
     /* The mutex is already locked. */

     if (mi->type != Normal) {
       /* Recursive or Errorcheck */
       if (mi->owner == GetCurrentThreadId()) {
         /* FIXME: A recursive mutex should not need two atomic ops when locking
            recursively.  We could rewrite by doing compare-and-swap instead of
            test-and-set the first time, but it would lead to more code
            duplication and add a conditional branch to the critical path. */
         __sync_bool_compare_and_swap(&mi->state, Locked, old_state);
         if (mi->type == Recursive) {
           mi->rec_lock++;
           return 0;
         } else {
           /* type == Errorcheck */
           return EDEADLK;
         }
       }
     }

     /* Make sure there is an event object on which to wait. */
     if (mi->event == NULL) {
       /* Make an auto-reset event object. */
       HANDLE ev = CreateEvent(NULL, false, false, NULL);
       if (ev == NULL) {
         switch (GetLastError()) {
         case ERROR_ACCESS_DENIED:
           return EPERM;
         default:
           return ENOMEM;    /* Probably accurate enough. */
         }
       }
       if (!__sync_bool_compare_and_swap(&mi->event, NULL, ev)) {
         /* Someone created the event before us. */
         CloseHandle(ev);
       }
     }

     /* At this point, mi->event is non-NULL. */

     while (__sync_lock_test_and_set(&mi->state, Waiting) != Unlocked) {
       /* For timed locking attempts, it is possible (although unlikely)
          that we are woken up but someone else grabs the lock before us,
          and we have to go back to sleep again. In that case, the total
          wait may be longer than expected. */

       unsigned r = WaitForSingleObject(mi->event, timeout);
       switch (r) {
       case WAIT_TIMEOUT:
         return ETIMEDOUT;
       case WAIT_OBJECT_0:
         break;
       default:
         return EINVAL;
       }
     }
   }

   if (mi->type != Normal)
     mi->owner = GetCurrentThreadId();

   return 0;
 }

 int
 pthread_mutex_lock (pthread_mutex_t *m)
 {
   return pthread_mutex_lock_intern (m, INFINITE);
 }

 int pthread_mutex_timedlock(pthread_mutex_t *m, const struct timespec *ts)
 {
   unsigned long long patience;
   if (ts != NULL) {
     unsigned long long end = _pthread_time_in_ms_from_timespec(ts);
     unsigned long long now = _pthread_time_in_ms();
     patience = end > now ? end - now : 0;
     if (patience > 0xffffffff)
       patience = INFINITE;
   } else {
     patience = INFINITE;
   }
   return pthread_mutex_lock_intern(m, patience);
 }

 int pthread_mutex_unlock(pthread_mutex_t *m)
 {
   /* Here m might an initialiser of an error-checking or recursive mutex, in
      which case the behaviour is well-defined, so we can't skip this check. */
   mutex_impl_t *mi = mutex_impl(m);
   if (mi == NULL)
     return ENOMEM;

   if (unlikely(mi->type != Normal)) {
     if (mi->state == Unlocked)
       return EINVAL;
     if (mi->owner != GetCurrentThreadId())
       return EPERM;
     if (mi->rec_lock > 0) {
       mi->rec_lock--;
       return 0;
     }
     mi->owner = (DWORD)-1;
   }
   if (unlikely(__sync_lock_test_and_set(&mi->state, Unlocked) == Waiting)) {
     if (!SetEvent(mi->event))
       return EPERM;
   }
   return 0;
 }

 int pthread_mutex_trylock(pthread_mutex_t *m)
 {
   mutex_impl_t *mi = mutex_impl(m);
   if (mi == NULL)
     return ENOMEM;

   if (__sync_bool_compare_and_swap(&mi->state, Unlocked, Locked)) {
     if (mi->type != Normal)
       mi->owner = GetCurrentThreadId();
     return 0;
   } else {
     if (mi->type == Recursive && mi->owner == GetCurrentThreadId()) {
       mi->rec_lock++;
       return 0;
     }
     return EBUSY;
   }
 }

 int
 pthread_mutex_init (pthread_mutex_t *m, const pthread_mutexattr_t *a)
 {
   pthread_mutex_t init = PTHREAD_MUTEX_INITIALIZER;
   if (a != NULL) {
     int pshared;
     if (pthread_mutexattr_getpshared(a, &pshared) == 0
         && pshared == PTHREAD_PROCESS_SHARED)
       return ENOSYS;

     int type;
     if (pthread_mutexattr_gettype(a, &type) == 0) {
       switch (type) {
       case PTHREAD_MUTEX_ERRORCHECK:
         init = PTHREAD_ERRORCHECK_MUTEX_INITIALIZER;
         break;
       case PTHREAD_MUTEX_RECURSIVE:
         init = PTHREAD_RECURSIVE_MUTEX_INITIALIZER;
         break;
       default:
         init = PTHREAD_MUTEX_INITIALIZER;
         break;
       }
     }
   }
   *m = init;
   return 0;
 }

 int pthread_mutex_destroy (pthread_mutex_t *m)
 {
   mutex_impl_t *mi = *m;
   if (!is_static_initializer(mi)) {
     if (mi->event != NULL)
       CloseHandle(mi->event);
     free(mi);
     /* Sabotage attempts to re-use the mutex before initialising it again. */
     *m = NULL;
   }

   return 0;
 }

 int pthread_mutexattr_init(pthread_mutexattr_t *a)
 {
   *a = PTHREAD_MUTEX_NORMAL | (PTHREAD_PROCESS_PRIVATE << 3);
   return 0;
 }

 int pthread_mutexattr_destroy(pthread_mutexattr_t *a)
 {
   if (!a)
     return EINVAL;

   return 0;
 }

 int pthread_mutexattr_gettype(const pthread_mutexattr_t *a, int *type)
 {
   if (!a || !type)
     return EINVAL;

   *type = *a & 3;

   return 0;
 }

 int pthread_mutexattr_settype(pthread_mutexattr_t *a, int type)
 {
     if (!a || (type != PTHREAD_MUTEX_NORMAL && type != PTHREAD_MUTEX_RECURSIVE && type != PTHREAD_MUTEX_ERRORCHECK))
       return EINVAL;
     *a &= ~3;
     *a |= type;

     return 0;
 }

 int pthread_mutexattr_getpshared(const pthread_mutexattr_t *a, int *type)
 {
     if (!a || !type)
       return EINVAL;
     *type = (*a & 4 ? PTHREAD_PROCESS_SHARED : PTHREAD_PROCESS_PRIVATE);

     return 0;
 }

 int pthread_mutexattr_setpshared(pthread_mutexattr_t * a, int type)
 {
     int r = 0;
     if (!a || (type != PTHREAD_PROCESS_SHARED
 	&& type != PTHREAD_PROCESS_PRIVATE))
       return EINVAL;
     if (type == PTHREAD_PROCESS_SHARED)
     {
       type = PTHREAD_PROCESS_PRIVATE;
       r = ENOSYS;
     }
     type = (type == PTHREAD_PROCESS_SHARED ? 4 : 0);

     *a &= ~4;
     *a |= type;

     return r;
 }

 int pthread_mutexattr_getprotocol(const pthread_mutexattr_t *a, int *type)
 {
     *type = *a & (8 + 16);

     return 0;
 }

 int pthread_mutexattr_setprotocol(pthread_mutexattr_t *a, int type)
 {
     if ((type & (8 + 16)) != 8 + 16) return EINVAL;

     *a &= ~(8 + 16);
     *a |= type;

     return 0;
 }

 int pthread_mutexattr_getprioceiling(const pthread_mutexattr_t *a, int * prio)
 {
     *prio = *a / PTHREAD_PRIO_MULT;
     return 0;
 }

 int pthread_mutexattr_setprioceiling(pthread_mutexattr_t *a, int prio)
 {
     *a &= (PTHREAD_PRIO_MULT - 1);
     *a += prio * PTHREAD_PRIO_MULT;

     return 0;
 }
	/*
	Copyright (c) 2011, 2014 mingw-w64 project
	Copyright (c) 2015 Intel Corporation

	Permission is hereby granted, free of charge, to any person obtaining a
	copy of this software and associated documentation files (the "Software"),
	to deal in the Software without restriction, including without limitation
	the rights to use, copy, modify, merge, publish, distribute, sublicense,
	and/or sell copies of the Software, and to permit persons to whom the
	Software is furnished to do so, subject to the following conditions:

	The above copyright notice and this permission notice shall be included in
	all copies or substantial portions of the Software.

	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
	FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
	DEALINGS IN THE SOFTWARE.
	*/

	#include <windows.h>
	#include <stdio.h>
	#include <malloc.h>
	#include <stdbool.h>
	#include "pthread.h"
	#include "misc.h"

	typedef enum {
	Unlocked, /* Not locked. */
	Locked, /* Locked but without waiters. */
	Waiting, /* Locked, may have waiters. */
	} mutex_state_t;

	typedef enum {
	Normal,
	Errorcheck,
	Recursive,
	} mutex_type_t;

	/* The heap-allocated part of a mutex. */
	typedef struct {
	mutex_state_t state;
	mutex_type_t type;
	HANDLE event; /* Auto-reset event, or NULL if not yet allocated. */
	unsigned rec_lock; /* For recursive mutexes, the number of times the
	mutex has been locked in excess by the same thread. */
	volatile DWORD owner; /* For recursive and error-checking mutexes, the
	ID of the owning thread if the mutex is locked. */
	} mutex_impl_t;

	/* Whether a mutex is still a static initializer (not a pointer to
	a mutex_impl_t). */
	static bool
	is_static_initializer(pthread_mutex_t m)
	{
	return (uintptr_t)m >= (uintptr_t)-3;
	}

	/* Create and return the implementation part of a mutex from a static
	initialiser. Return NULL on out-of-memory error. */
	static WINPTHREADS_ATTRIBUTE((noinline)) mutex_impl_t *
	mutex_impl_init(pthread_mutex_t m, mutex_impl_t mi)
	{
	mutex_impl_t *new_mi = malloc(sizeof(mutex_impl_t));
	if (new_mi == NULL)
	return NULL;
	new_mi->state = Unlocked;
	new_mi->type = (mi == PTHREAD_RECURSIVE_MUTEX_INITIALIZER ? Recursive
	: mi == PTHREAD_ERRORCHECK_MUTEX_INITIALIZER ? Errorcheck
	: Normal);
	new_mi->event = NULL;
	new_mi->rec_lock = 0;
	new_mi->owner = (DWORD)-1;
	if (__sync_bool_compare_and_swap(m, mi, new_mi)) {
	return new_mi;
	} else {
	/* Someone created the struct before us. */
	free(new_mi);
	return *m;
	}
	}

	#define likely(cond) __builtin_expect((cond) != 0, 1)
	#define unlikely(cond) __builtin_expect((cond) != 0, 0)

	/* Return the implementation part of a mutex, creating it if necessary.
	Return NULL on out-of-memory error. */
	static inline mutex_impl_t *
	mutex_impl(pthread_mutex_t *m)
	{
	mutex_impl_t mi = m;
	if (is_static_initializer(mi)) {
	return mutex_impl_init(m, mi);
	} else {
	/* mi cannot be null here; avoid a test in the fast path. */
	if (mi == NULL)
	__builtin_unreachable();
	return mi;
	}
	}

	/* Lock a mutex. Give up after 'timeout' ms (with ETIMEDOUT),
	or never if timeout=INFINITE. */
	static inline int
	pthread_mutex_lock_intern (pthread_mutex_t *m, DWORD timeout)
	{
	mutex_impl_t *mi = mutex_impl(m);
	if (mi == NULL)
	return ENOMEM;

	mutex_state_t old_state = __sync_lock_test_and_set(&mi->state, Locked);
	if (unlikely(old_state != Unlocked)) {
	/* The mutex is already locked. */

	if (mi->type != Normal) {
	/* Recursive or Errorcheck */
	if (mi->owner == GetCurrentThreadId()) {
	/* FIXME: A recursive mutex should not need two atomic ops when locking
	recursively. We could rewrite by doing compare-and-swap instead of
	test-and-set the first time, but it would lead to more code
	duplication and add a conditional branch to the critical path. */
	__sync_bool_compare_and_swap(&mi->state, Locked, old_state);
	if (mi->type == Recursive) {
	mi->rec_lock++;
	return 0;
	} else {
	/* type == Errorcheck */
	return EDEADLK;
	}
	}
	}

	/* Make sure there is an event object on which to wait. */
	if (mi->event == NULL) {
	/* Make an auto-reset event object. */
	HANDLE ev = CreateEvent(NULL, false, false, NULL);
	if (ev == NULL) {
	switch (GetLastError()) {
	case ERROR_ACCESS_DENIED:
	return EPERM;
	default:
	return ENOMEM; /* Probably accurate enough. */
	}
	}
	if (!__sync_bool_compare_and_swap(&mi->event, NULL, ev)) {
	/* Someone created the event before us. */
	CloseHandle(ev);
	}
	}

	/* At this point, mi->event is non-NULL. */

	while (__sync_lock_test_and_set(&mi->state, Waiting) != Unlocked) {
	/* For timed locking attempts, it is possible (although unlikely)
	that we are woken up but someone else grabs the lock before us,
	and we have to go back to sleep again. In that case, the total
	wait may be longer than expected. */

	unsigned r = WaitForSingleObject(mi->event, timeout);
	switch (r) {
	case WAIT_TIMEOUT:
	return ETIMEDOUT;
	case WAIT_OBJECT_0:
	break;
	default:
	return EINVAL;
	}
	}
	}

	if (mi->type != Normal)
	mi->owner = GetCurrentThreadId();

	return 0;
	}

	int
	pthread_mutex_lock (pthread_mutex_t *m)
	{
	return pthread_mutex_lock_intern (m, INFINITE);
	}

	int pthread_mutex_timedlock(pthread_mutex_t m, const struct timespec ts)
	{
	unsigned long long patience;
	if (ts != NULL) {
	unsigned long long end = _pthread_time_in_ms_from_timespec(ts);
	unsigned long long now = _pthread_time_in_ms();
	patience = end > now ? end - now : 0;
	if (patience > 0xffffffff)
	patience = INFINITE;
	} else {
	patience = INFINITE;
	}
	return pthread_mutex_lock_intern(m, patience);
	}

	int pthread_mutex_unlock(pthread_mutex_t *m)
	{
	/* Here m might an initialiser of an error-checking or recursive mutex, in
	which case the behaviour is well-defined, so we can't skip this check. */
	mutex_impl_t *mi = mutex_impl(m);
	if (mi == NULL)
	return ENOMEM;

	if (unlikely(mi->type != Normal)) {
	if (mi->state == Unlocked)
	return EINVAL;
	if (mi->owner != GetCurrentThreadId())
	return EPERM;
	if (mi->rec_lock > 0) {
	mi->rec_lock--;
	return 0;
	}
	mi->owner = (DWORD)-1;
	}
	if (unlikely(__sync_lock_test_and_set(&mi->state, Unlocked) == Waiting)) {
	if (!SetEvent(mi->event))
	return EPERM;
	}
	return 0;
	}

	int pthread_mutex_trylock(pthread_mutex_t *m)
	{
	mutex_impl_t *mi = mutex_impl(m);
	if (mi == NULL)
	return ENOMEM;

	if (__sync_bool_compare_and_swap(&mi->state, Unlocked, Locked)) {
	if (mi->type != Normal)
	mi->owner = GetCurrentThreadId();
	return 0;
	} else {
	if (mi->type == Recursive && mi->owner == GetCurrentThreadId()) {
	mi->rec_lock++;
	return 0;
	}
	return EBUSY;
	}
	}

	int
	pthread_mutex_init (pthread_mutex_t m, const pthread_mutexattr_t a)
	{
	pthread_mutex_t init = PTHREAD_MUTEX_INITIALIZER;
	if (a != NULL) {
	int pshared;
	if (pthread_mutexattr_getpshared(a, &pshared) == 0
	&& pshared == PTHREAD_PROCESS_SHARED)
	return ENOSYS;

	int type;
	if (pthread_mutexattr_gettype(a, &type) == 0) {
	switch (type) {
	case PTHREAD_MUTEX_ERRORCHECK:
	init = PTHREAD_ERRORCHECK_MUTEX_INITIALIZER;
	break;
	case PTHREAD_MUTEX_RECURSIVE:
	init = PTHREAD_RECURSIVE_MUTEX_INITIALIZER;
	break;
	default:
	init = PTHREAD_MUTEX_INITIALIZER;
	break;
	}
	}
	}
	*m = init;
	return 0;
	}

	int pthread_mutex_destroy (pthread_mutex_t *m)
	{
	mutex_impl_t mi = m;
	if (!is_static_initializer(mi)) {
	if (mi->event != NULL)
	CloseHandle(mi->event);
	free(mi);
	/* Sabotage attempts to re-use the mutex before initialising it again. */
	*m = NULL;
	}

	return 0;
	}

	int pthread_mutexattr_init(pthread_mutexattr_t *a)
	{
	*a = PTHREAD_MUTEX_NORMAL \| (PTHREAD_PROCESS_PRIVATE << 3);
	return 0;
	}

	int pthread_mutexattr_destroy(pthread_mutexattr_t *a)
	{
	if (!a)
	return EINVAL;

	return 0;
	}

	int pthread_mutexattr_gettype(const pthread_mutexattr_t a, int type)
	{
	if (!a \|\| !type)
	return EINVAL;

	type = a & 3;

	return 0;
	}

	int pthread_mutexattr_settype(pthread_mutexattr_t *a, int type)
	{
	if (!a \|\| (type != PTHREAD_MUTEX_NORMAL && type != PTHREAD_MUTEX_RECURSIVE && type != PTHREAD_MUTEX_ERRORCHECK))
	return EINVAL;
	*a &= ~3;
	*a \|= type;

	return 0;
	}

	int pthread_mutexattr_getpshared(const pthread_mutexattr_t a, int type)
	{
	if (!a \|\| !type)
	return EINVAL;
	type = (a & 4 ? PTHREAD_PROCESS_SHARED : PTHREAD_PROCESS_PRIVATE);

	return 0;
	}

	int pthread_mutexattr_setpshared(pthread_mutexattr_t * a, int type)
	{
	int r = 0;
	if (!a \|\| (type != PTHREAD_PROCESS_SHARED
	&& type != PTHREAD_PROCESS_PRIVATE))
	return EINVAL;
	if (type == PTHREAD_PROCESS_SHARED)
	{
	type = PTHREAD_PROCESS_PRIVATE;
	r = ENOSYS;
	}
	type = (type == PTHREAD_PROCESS_SHARED ? 4 : 0);

	*a &= ~4;
	*a \|= type;

	return r;
	}

	int pthread_mutexattr_getprotocol(const pthread_mutexattr_t a, int type)
	{
	type = a & (8 + 16);

	return 0;
	}

	int pthread_mutexattr_setprotocol(pthread_mutexattr_t *a, int type)
	{
	if ((type & (8 + 16)) != 8 + 16) return EINVAL;

	*a &= ~(8 + 16);
	*a \|= type;

	return 0;
	}

	int pthread_mutexattr_getprioceiling(const pthread_mutexattr_t a, int prio)
	{
	prio = a / PTHREAD_PRIO_MULT;
	return 0;
	}

	int pthread_mutexattr_setprioceiling(pthread_mutexattr_t *a, int prio)
	{
	*a &= (PTHREAD_PRIO_MULT - 1);
	a += prio PTHREAD_PRIO_MULT;

	return 0;
	}