libc-top-half/musl/src/thread/pthread_key_create.c

   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 #ifdef __wasilibc_unmodified_upstream
  54         __block_app_sigs(&set);
  55 #endif
  56         __pthread_rwlock_wrlock(&key_lock);
  57
  58         __tl_lock();
  59         do td->tsd[k] = 0;
  60         while ((td=td->next)!=self);
  61         __tl_unlock();
  62
  63         keys[k] = 0;
  64
  65         __pthread_rwlock_unlock(&key_lock);
  66 #ifdef __wasilibc_unmodified_upstream
  67         __restore_sigs(&set);
  68 #endif
  69
  70         return 0;
  71 }
  72
  73 void __pthread_tsd_run_dtors()
  74 {
  75         pthread_t self = __pthread_self();
  76         int i, j;
  77         for (j=0; self->tsd_used && j<PTHREAD_DESTRUCTOR_ITERATIONS; j++) {
  78                 __pthread_rwlock_rdlock(&key_lock);
  79                 self->tsd_used = 0;
  80                 for (i=0; i<PTHREAD_KEYS_MAX; i++) {
  81                         void *val = self->tsd[i];
  82                         void (*dtor)(void *) = keys[i];
  83                         self->tsd[i] = 0;
  84                         if (val && dtor && dtor != nodtor) {
  85                                 __pthread_rwlock_unlock(&key_lock);
  86                                 dtor(val);
  87                                 __pthread_rwlock_rdlock(&key_lock);
  88                         }
  89                 }
  90                 __pthread_rwlock_unlock(&key_lock);
  91         }
  92 }
  93
  94 weak_alias(__pthread_key_create, pthread_key_create);
  95 weak_alias(__pthread_key_delete, pthread_key_delete);