uclibc-ng/libpthread/linuxthreads/specific.c

/* Linuxthreads - a simple clone()-based implementation of Posix        */
/* threads for Linux.                                                   */
/* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr)              */
/*                                                                      */
/* This program is free software; you can redistribute it and/or        */
/* modify it under the terms of the GNU Library General Public License  */
/* as published by the Free Software Foundation; either version 2       */
/* of the License, or (at your option) any later version.               */
/*                                                                      */
/* This program is distributed in the hope that it will be useful,      */
/* but WITHOUT ANY WARRANTY; without even the implied warranty of       */
/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        */
/* GNU Library General Public License for more details.                 */

/* Thread-specific data */

#include <features.h>
#include <errno.h>
#include <stddef.h>
#include <stdlib.h>
#include "pthread.h"
#include "internals.h"
#include "spinlock.h"
#include "restart.h"

/* Table of keys. */

static struct pthread_key_struct pthread_keys[PTHREAD_KEYS_MAX] =
  { { 0, NULL } };

/* For debugging purposes put the maximum number of keys in a variable.  */
const int __linuxthreads_pthread_keys_max = PTHREAD_KEYS_MAX;
const int __linuxthreads_pthread_key_2ndlevel_size = PTHREAD_KEY_2NDLEVEL_SIZE;

/* Mutex to protect access to pthread_keys */

static pthread_mutex_t pthread_keys_mutex = PTHREAD_MUTEX_INITIALIZER;

/* Create a new key */

int pthread_key_create(pthread_key_t * key, destr_function destr)
{
  int i;

  __pthread_mutex_lock(&pthread_keys_mutex);
  for (i = 0; i < PTHREAD_KEYS_MAX; i++) {
    if (! pthread_keys[i].in_use) {
      /* Mark key in use */
      pthread_keys[i].in_use = 1;
      pthread_keys[i].destr = destr;
      __pthread_mutex_unlock(&pthread_keys_mutex);
      *key = i;
      return 0;
    }
  }
  __pthread_mutex_unlock(&pthread_keys_mutex);
  return EAGAIN;
}

/* Delete a key */
int pthread_key_delete(pthread_key_t key)
{
    pthread_descr self = thread_self();

    __pthread_mutex_lock(&pthread_keys_mutex);
    if (key >= PTHREAD_KEYS_MAX || !pthread_keys[key].in_use) {
	__pthread_mutex_unlock(&pthread_keys_mutex);
	return EINVAL;
    }
    pthread_keys[key].in_use = 0;
    pthread_keys[key].destr = NULL;

    /* Set the value of the key to NULL in all running threads, so
       that if the key is reallocated later by pthread_key_create, its
       associated values will be NULL in all threads.
       Do nothing if no threads have been created yet.  */
    if (__pthread_manager_request != -1)
    {
	pthread_descr th;
	unsigned int idx1st, idx2nd;

	idx1st = key / PTHREAD_KEY_2NDLEVEL_SIZE;
	idx2nd = key % PTHREAD_KEY_2NDLEVEL_SIZE;
	th = self;
	do {
	    /* If the thread already is terminated don't modify the memory.  */
	    if (!th->p_terminated && th->p_specific[idx1st] != NULL)
		th->p_specific[idx1st][idx2nd] = NULL;
	    th = th->p_nextlive;
	} while (th != self);
    }

    __pthread_mutex_unlock(&pthread_keys_mutex);
    return 0;
}

/* Set the value of a key */

int pthread_setspecific(pthread_key_t key, const void * pointer)
{
    pthread_descr self = thread_self();
    unsigned int idx1st, idx2nd;

    if (key >= PTHREAD_KEYS_MAX || !pthread_keys[key].in_use)
	return EINVAL;
    idx1st = key / PTHREAD_KEY_2NDLEVEL_SIZE;
    idx2nd = key % PTHREAD_KEY_2NDLEVEL_SIZE;
    if (THREAD_GETMEM_NC(self, p_specific[idx1st]) == NULL) {
	void *newp = calloc(PTHREAD_KEY_2NDLEVEL_SIZE, sizeof (void *));
	if (newp == NULL)
	    return ENOMEM;
	THREAD_SETMEM_NC(self, p_specific[idx1st], newp);
    }
    THREAD_GETMEM_NC(self, p_specific[idx1st])[idx2nd] = (void *) pointer;
    return 0;
}

/* Get the value of a key */

void * pthread_getspecific(pthread_key_t key)
{
    pthread_descr self = thread_self();
    unsigned int idx1st, idx2nd;

    if (key >= PTHREAD_KEYS_MAX)
	return NULL;
    idx1st = key / PTHREAD_KEY_2NDLEVEL_SIZE;
    idx2nd = key % PTHREAD_KEY_2NDLEVEL_SIZE;
    if (THREAD_GETMEM_NC(self, p_specific[idx1st]) == NULL
	    || !pthread_keys[key].in_use)
	return NULL;
    return THREAD_GETMEM_NC(self, p_specific[idx1st])[idx2nd];
}

/* Call the destruction routines on all keys */

void __pthread_destroy_specifics(void)
{
    pthread_descr self = thread_self();
    int i, j, round, found_nonzero;
    destr_function destr;
    void * data;

    for (round = 0, found_nonzero = 1;
	    found_nonzero && round < PTHREAD_DESTRUCTOR_ITERATIONS;
	    round++) {
	found_nonzero = 0;
	for (i = 0; i < PTHREAD_KEY_1STLEVEL_SIZE; i++)
	    if (THREAD_GETMEM_NC(self, p_specific[i]) != NULL)
		for (j = 0; j < PTHREAD_KEY_2NDLEVEL_SIZE; j++) {
		    destr = pthread_keys[i * PTHREAD_KEY_2NDLEVEL_SIZE + j].destr;
		    data = THREAD_GETMEM_NC(self, p_specific[i])[j];
		    if (destr != NULL && data != NULL) {
			THREAD_GETMEM_NC(self, p_specific[i])[j] = NULL;
			destr(data);
			found_nonzero = 1;
		    }
		}
    }
    __pthread_lock(THREAD_GETMEM(self, p_lock), self);
    for (i = 0; i < PTHREAD_KEY_1STLEVEL_SIZE; i++) {
	if (THREAD_GETMEM_NC(self, p_specific[i]) != NULL) {
	    free(THREAD_GETMEM_NC(self, p_specific[i]));
	    THREAD_SETMEM_NC(self, p_specific[i], NULL);
	}
    }
    __pthread_unlock(THREAD_GETMEM(self, p_lock));
}