src/thread/pthread_key_create.c

   1 #include "pthread_impl.h"
   2 #include "fork_impl.h"
   3
   4 volatile size_t __pthread_tsd_size = sizeof(void *) * PTHREAD_KEYS_MAX;
   5 void *__pthread_tsd_main[PTHREAD_KEYS_MAX] = { 0 };
   6
   7 static void (*keys[PTHREAD_KEYS_MAX])(void *);
   8
   9 static pthread_rwlock_t key_lock = PTHREAD_RWLOCK_INITIALIZER;
  10
  11 static pthread_key_t next_key;
  12
  13 static void nodtor(void *dummy)
  14 {
  15 }
  16
  17 static void dummy_0(void)
  18 {
  19 }
  20
  21 weak_alias(dummy_0, __tl_lock);
  22 weak_alias(dummy_0, __tl_unlock);
  23
  24 void __pthread_key_atfork(int who)
  25 {
  26         if (who<0) __pthread_rwlock_rdlock(&key_lock);
  27         else if (!who) __pthread_rwlock_unlock(&key_lock);
  28         else key_lock = (pthread_rwlock_t)PTHREAD_RWLOCK_INITIALIZER;
  29 }
  30
  31 int __pthread_key_create(pthread_key_t *k, void (*dtor)(void *))
  32 {
  33         pthread_t self = __pthread_self();
  34
  35         /* This can only happen in the main thread before
  36          * pthread_create has been called. */
  37         if (!self->tsd) self->tsd = __pthread_tsd_main;
  38
  39         /* Purely a sentinel value since null means slot is free. */
  40         if (!dtor) dtor = nodtor;
  41
  42         __pthread_rwlock_wrlock(&key_lock);
  43         pthread_key_t j = next_key;
  44         do {
  45                 if (!keys[j]) {
  46                         keys[next_key = *k = j] = dtor;
  47                         __pthread_rwlock_unlock(&key_lock);
  48                         return 0;
  49                 }
  50         } while ((j=(j+1)%PTHREAD_KEYS_MAX) != next_key);
  51
  52         __pthread_rwlock_unlock(&key_lock);
  53         return EAGAIN;
  54 }
  55
  56 int __pthread_key_delete(pthread_key_t k)
  57 {
  58         sigset_t set;
  59         pthread_t self = __pthread_self(), td=self;
  60
  61         __block_app_sigs(&set);
  62         __pthread_rwlock_wrlock(&key_lock);
  63
  64         __tl_lock();
  65         do td->tsd[k] = 0;
  66         while ((td=td->next)!=self);
  67         __tl_unlock();
  68
  69         keys[k] = 0;
  70
  71         __pthread_rwlock_unlock(&key_lock);
  72         __restore_sigs(&set);
  73
  74         return 0;
  75 }
  76
  77 void __pthread_tsd_run_dtors()
  78 {
  79         pthread_t self = __pthread_self();
  80         int i, j;
  81         for (j=0; self->tsd_used && j<PTHREAD_DESTRUCTOR_ITERATIONS; j++) {
  82                 __pthread_rwlock_rdlock(&key_lock);
  83                 self->tsd_used = 0;
  84                 for (i=0; i<PTHREAD_KEYS_MAX; i++) {
  85                         void *val = self->tsd[i];
  86                         void (*dtor)(void *) = keys[i];
  87                         self->tsd[i] = 0;
  88                         if (val && dtor && dtor != nodtor) {
  89                                 __pthread_rwlock_unlock(&key_lock);
  90                                 dtor(val);
  91                                 __pthread_rwlock_rdlock(&key_lock);
  92                         }
  93                 }
  94                 __pthread_rwlock_unlock(&key_lock);
  95         }
  96 }
  97
  98 weak_alias(__pthread_key_create, pthread_key_create);
  99 weak_alias(__pthread_key_delete, pthread_key_delete);