github.com/afumu/libc@v0.0.6/musl/src/thread/pthread_key_create.c (about)

     1  #include "pthread_impl.h"
     2  
     3  volatile size_t __pthread_tsd_size = sizeof(void *) * PTHREAD_KEYS_MAX;
     4  void *__pthread_tsd_main[PTHREAD_KEYS_MAX] = { 0 };
     5  
     6  static void (*keys[PTHREAD_KEYS_MAX])(void *);
     7  
     8  static pthread_rwlock_t key_lock = PTHREAD_RWLOCK_INITIALIZER;
     9  
    10  static pthread_key_t next_key;
    11  
    12  static void nodtor(void *dummy)
    13  {
    14  }
    15  
    16  static void dummy_0(void)
    17  {
    18  }
    19  
    20  weak_alias(dummy_0, __tl_lock);
    21  weak_alias(dummy_0, __tl_unlock);
    22  
    23  int __pthread_key_create(pthread_key_t *k, void (*dtor)(void *))
    24  {
    25  	pthread_t self = __pthread_self();
    26  
    27  	/* This can only happen in the main thread before
    28  	 * pthread_create has been called. */
    29  	if (!self->tsd) self->tsd = __pthread_tsd_main;
    30  
    31  	/* Purely a sentinel value since null means slot is free. */
    32  	if (!dtor) dtor = nodtor;
    33  
    34  	__pthread_rwlock_wrlock(&key_lock);
    35  	pthread_key_t j = next_key;
    36  	do {
    37  		if (!keys[j]) {
    38  			keys[next_key = *k = j] = dtor;
    39  			__pthread_rwlock_unlock(&key_lock);
    40  			return 0;
    41  		}
    42  	} while ((j=(j+1)%PTHREAD_KEYS_MAX) != next_key);
    43  
    44  	__pthread_rwlock_unlock(&key_lock);
    45  	return EAGAIN;
    46  }
    47  
    48  int __pthread_key_delete(pthread_key_t k)
    49  {
    50  	sigset_t set;
    51  	pthread_t self = __pthread_self(), td=self;
    52  
    53  	__block_app_sigs(&set);
    54  	__pthread_rwlock_wrlock(&key_lock);
    55  
    56  	__tl_lock();
    57  	do td->tsd[k] = 0;
    58  	while ((td=td->next)!=self);
    59  	__tl_unlock();
    60  
    61  	keys[k] = 0;
    62  
    63  	__pthread_rwlock_unlock(&key_lock);
    64  	__restore_sigs(&set);
    65  
    66  	return 0;
    67  }
    68  
    69  void __pthread_tsd_run_dtors()
    70  {
    71  	pthread_t self = __pthread_self();
    72  	int i, j;
    73  	for (j=0; self->tsd_used && j<PTHREAD_DESTRUCTOR_ITERATIONS; j++) {
    74  		__pthread_rwlock_rdlock(&key_lock);
    75  		self->tsd_used = 0;
    76  		for (i=0; i<PTHREAD_KEYS_MAX; i++) {
    77  			void *val = self->tsd[i];
    78  			void (*dtor)(void *) = keys[i];
    79  			self->tsd[i] = 0;
    80  			if (val && dtor && dtor != nodtor) {
    81  				__pthread_rwlock_unlock(&key_lock);
    82  				dtor(val);
    83  				__pthread_rwlock_rdlock(&key_lock);
    84  			}
    85  		}
    86  		__pthread_rwlock_unlock(&key_lock);
    87  	}
    88  }
    89  
    90  weak_alias(__pthread_key_create, pthread_key_create);
    91  weak_alias(__pthread_key_delete, pthread_key_delete);