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/*
* tsd.c
*
* Description:
* POSIX thread functions which implement thread-specific data (TSD).
*/
#include "pthread.h"
#include "implement.h"
/*
* Code contributed by John E. Bossom <JEB>.
*/
int
pthread_key_create (pthread_key_t * key, void (*destructor) (void *))
/*
* ------------------------------------------------------
* DOCPUBLIC
* This function creates a thread-specific data key visible
* to all threads. All existing and new threads have a value
* NULL for key until set using pthread_setspecific. When any
* thread with a non-NULL value for key terminates, 'destructor'
* is called with key's current value for that thread.
*
* PARAMETERS
* key
* pointer to an instance of pthread_key_t
*
*
* DESCRIPTION
* This function creates a thread-specific data key visible
* to all threads. All existing and new threads have a value
* NULL for key until set using pthread_setspecific. When any
* thread with a non-NULL value for key terminates, 'destructor'
* is called with key's current value for that thread.
*
* RESULTS
* 0 successfully created semaphore,
* EAGAIN insufficient resources or PTHREAD_KEYS_MAX
* exceeded,
* ENOMEM insufficient memory to create the key,
*
* ------------------------------------------------------
*/
{
int result = 0;
if ((*key = (pthread_key_t) calloc (1, sizeof (**key))) == NULL)
{
result = ENOMEM;
}
else if (((*key)->key = TlsAlloc ()) == TLS_OUT_OF_INDEXES)
{
/*
* Create system key
*/
result = EAGAIN;
free (*key);
*key = NULL;
}
else if (destructor != NULL)
{
/*
* Have to manage associations between thread and key;
* Therefore, need a lock that allows multiple threads
* to gain exclusive access to the key->threads list
*/
result = pthread_mutex_init (&((*key)->threadsLock), NULL);
if (result != 0)
{
TlsFree ((*key)->key);
free (*key);
*key = NULL;
}
(*key)->destructor = destructor;
}
return (result);
}
int
pthread_key_delete (pthread_key_t key)
/*
* ------------------------------------------------------
* DOCPUBLIC
* This function deletes a thread-specific data key. This
* does not change the value of the thread spcific data key
* for any thread and does not run the key's destructor
* in any thread so it should be used with caution.
*
* PARAMETERS
* key
* pointer to an instance of pthread_key_t
*
*
* DESCRIPTION
* This function deletes a thread-specific data key. This
* does not change the value of the thread spcific data key
* for any thread and does not run the key's destructor
* in any thread so it should be used with caution.
*
* RESULTS
* 0 successfully deleted the key,
* EINVAL key is invalid,
*
* ------------------------------------------------------
*/
{
int result = 0;
if (key != NULL)
{
if (key->threads != NULL &&
pthread_mutex_lock (&(key->threadsLock)) == 0)
{
/*
* Run through all Thread<-->Key associations
* for this key.
* If the pthread_t still exits (ie the assoc->thread
* is not NULL) then leave the assoc for the thread to
* destroy.
* Notes:
* If assoc->thread is NULL, then the associated thread
* is no longer referencing this assoc.
* The association is only referenced
* by this key and must be released; otherwise
* the assoc will be destroyed when the thread is destroyed.
*/
ThreadKeyAssoc *assoc;
assoc = (ThreadKeyAssoc *) key->threads;
while (assoc != NULL)
{
if (pthread_mutex_lock (&(assoc->lock)) == 0)
{
ThreadKeyAssoc *next;
assoc->key = NULL;
next = assoc->nextThread;
assoc->nextThread = NULL;
pthread_mutex_unlock (&(assoc->lock));
_pthread_tkAssocDestroy (assoc);
assoc = next;
}
}
pthread_mutex_unlock (&(key->threadsLock));
}
TlsFree (key->key);
if (key->destructor != NULL)
{
pthread_mutex_destroy (&(key->threadsLock));
}
#if defined( _DEBUG )
memset ((char *) key, 0, sizeof (*key));
#endif
free (key);
}
return (result);
}
int
pthread_setspecific (pthread_key_t key, const void *value)
/*
* ------------------------------------------------------
* DOCPUBLIC
* This function initializes an unnamed semaphore. the
* initial value of the semaphore is 'value'
*
* PARAMETERS
* sem
* pointer to an instance of sem_t
*
*
* DESCRIPTION
* This function initializes an unnamed semaphore. The
* initial value of the semaphore is set to 'value'.
*
* RESULTS
* 0 successfully created semaphore,
* EINVAL 'sem' is not a valid semaphore,
* ENOSPC a required resource has been exhausted,
* ENOSYS semaphores are not supported,
* EPERM the process lacks appropriate privilege
*
* ------------------------------------------------------
*/
{
pthread_t self;
int result = 0;
if (key != _pthread_selfThreadKey)
{
/*
* Using pthread_self will implicitly create
* an instance of pthread_t for the current
* thread if one wasn't explicitly created
*/
self = pthread_self ();
}
else
{
/*
* Resolve catch-22 of registering thread with threadSelf
* key
*/
self = pthread_getspecific (_pthread_selfThreadKey);
if (self == NULL)
{
self = (pthread_t) value;
}
}
result = 0;
if (key != NULL)
{
ThreadKeyAssoc *assoc;
if (self != NULL &&
key->destructor != NULL &&
value != NULL)
{
/*
* Only require associations if we have to
* call user destroy routine.
* Don't need to locate an existing association
* when setting data to NULL for WIN32 since the
* data is stored with the operating system; not
* on the association; setting assoc to NULL short
* circuits the search.
*/
assoc = (ThreadKeyAssoc *) self->keys;
/*
* Locate existing association
*/
while (assoc != NULL)
{
if (assoc->key == key)
{
/*
* Association already exists
*/
break;
}
assoc = assoc->nextKey;
}
/*
* create an association if not found
*/
result = (assoc == NULL)
? _pthread_tkAssocCreate (&assoc, self, key)
: 0;
}
else
{
result = 0;
}
if (result == 0)
{
TlsSetValue (key->key, (LPVOID) value);
}
}
return (result);
} /* pthread_setspecific */
void *
pthread_getspecific (pthread_key_t key)
/*
* ------------------------------------------------------
* DOCPUBLIC
* This function returns the current value of key in the
* calling thread. If no value has been set for 'key' in
* the thread, NULL is returned.
*
* PARAMETERS
* key
* an instance of pthread_key_t
*
*
* DESCRIPTION
* This function returns the current value of key in the
* calling thread. If no value has been set for 'key' in
* the thread, NULL is returned.
*
* RESULTS
* key value
*
* ------------------------------------------------------
*/
{
return (TlsGetValue (key->key));
}
/* </JEB> */