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Add thread-locals for WIN32

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This commit is contained in:
Nicolas Williams
2016-04-14 14:38:49 -05:00
parent fca9bc45e2
commit 2f0c45f784
7 changed files with 408 additions and 5 deletions
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lib/base/dll.c Normal file
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/***********************************************************************
* Copyright (c) 2016 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*
**********************************************************************/
/*
* This is an implementation of thread-specific storage with
* destructors. WIN32 doesn't quite have this. Instead it has
* DllMain(), an entry point in every DLL that gets called to notify the
* DLL of thread/process "attach"/"detach" events.
*
* We use __thread (or __declspec(thread)) for the thread-local itself
* and DllMain() DLL_THREAD_DETACH events to drive destruction of
* thread-local values.
*
* When building in maintainer mode on non-Windows pthread systems this
* uses a single pthread key instead to implement multiple keys. This
* keeps the code from rotting when modified by non-Windows developers.
*/
#include "baselocl.h"
#ifdef WIN32
#include <windows.h>
#endif
#ifdef HEIM_WIN32_TLS
#include <assert.h>
#include <err.h>
#include <heim_threads.h>
#ifndef WIN32
#include <pthread.h>
#endif
/* Logical array of keys that grows lock-lessly */
typedef struct tls_keys tls_keys;
struct tls_keys {
void (**keys_dtors)(void *); /* array of destructors */
size_t keys_start_idx; /* index of first destructor */
size_t keys_num;
tls_keys *keys_next;
};
/*
* Well, not quite locklessly. We need synchronization primitives to do
* this locklessly. An atomic CAS will do.
*/
static HEIMDAL_MUTEX tls_key_defs_lock = HEIMDAL_MUTEX_INITIALIZER;
static tls_keys *tls_key_defs;
/* Logical array of values (per-thread; no locking needed here) */
struct tls_values {
void **values; /* realloc()ed */
size_t values_num;
};
static HEIMDAL_THREAD_LOCAL struct tls_values values;
#define DEAD_KEY ((void *)8)
static void
del_tls_for_thread(void *unused)
{
tls_keys *key_defs;
void (*dtor)(void*);
size_t i;
HEIMDAL_MUTEX_lock(&tls_key_defs_lock);
key_defs = tls_key_defs;
HEIMDAL_MUTEX_unlock(&tls_key_defs_lock);
if (key_defs == NULL)
return;
for (i = 0; i < values.values_num; i++) {
assert(i >= key_defs->keys_start_idx);
if (i >= key_defs->keys_start_idx + key_defs->keys_num) {
HEIMDAL_MUTEX_lock(&tls_key_defs_lock);
key_defs = key_defs->keys_next;
HEIMDAL_MUTEX_unlock(&tls_key_defs_lock);
assert(key_defs != NULL);
assert(i >= key_defs->keys_start_idx);
assert(i < key_defs->keys_start_idx + key_defs->keys_num);
}
dtor = key_defs->keys_dtors[i - key_defs->keys_start_idx];
if (values.values[i] != NULL && dtor != NULL && dtor != DEAD_KEY)
dtor(values.values[i]);
values.values[i] = NULL;
}
}
#if !defined(WIN32)
static pthread_key_t pt_key;
pthread_once_t pt_once = PTHREAD_ONCE_INIT;
static void
atexit_del_tls_for_thread(void)
{
del_tls_for_thread(NULL);
}
static void
create_pt_key(void)
{
int ret;
/* The main thread may not execute TLS destructors */
atexit(atexit_del_tls_for_thread);
ret = pthread_key_create(&pt_key, del_tls_for_thread);
if (ret != 0)
err(1, "pthread_key_create() failed");
}
#endif
int
heim_w32_key_create(HEIM_PRIV_thread_key *key, void (*dtor)(void *))
{
tls_keys *key_defs, *new_key_defs;
size_t i, k;
int ret = ENOMEM;
#if !defined(WIN32)
(void) pthread_once(&pt_once, create_pt_key);
(void) pthread_setspecific(pt_key, DEAD_KEY);
#endif
HEIMDAL_MUTEX_lock(&tls_key_defs_lock);
if (tls_key_defs == NULL) {
/* First key */
new_key_defs = calloc(1, sizeof(*new_key_defs));
if (new_key_defs == NULL) {
HEIMDAL_MUTEX_unlock(&tls_key_defs_lock);
return ENOMEM;
}
new_key_defs->keys_num = 8;
new_key_defs->keys_dtors = calloc(new_key_defs->keys_num,
sizeof(*new_key_defs->keys_dtors));
if (new_key_defs->keys_dtors == NULL) {
HEIMDAL_MUTEX_unlock(&tls_key_defs_lock);
free(new_key_defs);
return ENOMEM;
}
tls_key_defs = new_key_defs;
new_key_defs->keys_dtors[0] = dtor;
for (i = 1; i < new_key_defs->keys_num; i++)
new_key_defs->keys_dtors[i] = NULL;
HEIMDAL_MUTEX_unlock(&tls_key_defs_lock);
return 0;
}
for (key_defs = tls_key_defs;
key_defs != NULL;
key_defs = key_defs->keys_next) {
k = key_defs->keys_start_idx;
for (i = 0; i < key_defs->keys_num; i++, k++) {
if (key_defs->keys_dtors[i] == NULL) {
/* Found free slot; use it */
key_defs->keys_dtors[i] = dtor;
*key = k;
HEIMDAL_MUTEX_unlock(&tls_key_defs_lock);
return 0;
}
}
if (key_defs->keys_next != NULL)
continue;
/* Grow the registration array */
/* XXX DRY */
new_key_defs = calloc(1, sizeof(*new_key_defs));
if (new_key_defs == NULL)
break;
new_key_defs->keys_dtors =
calloc(key_defs->keys_num + key_defs->keys_num / 2,
sizeof(*new_key_defs->keys_dtors));
if (new_key_defs->keys_dtors == NULL) {
free(new_key_defs);
break;
}
new_key_defs->keys_start_idx = key_defs->keys_start_idx +
key_defs->keys_num;
new_key_defs->keys_num = key_defs->keys_num + key_defs->keys_num / 2;
new_key_defs->keys_dtors[i] = dtor;
for (i = 1; i < new_key_defs->keys_num; i++)
new_key_defs->keys_dtors[i] = NULL;
key_defs->keys_next = new_key_defs;
ret = 0;
break;
}
HEIMDAL_MUTEX_unlock(&tls_key_defs_lock);
return ret;
}
static void
key_lookup(HEIM_PRIV_thread_key key, tls_keys **kd,
size_t *dtor_idx, void (**dtor)(void *))
{
tls_keys *key_defs;
if (kd != NULL)
*kd = NULL;
if (dtor_idx != NULL)
*dtor_idx = 0;
if (dtor != NULL)
*dtor = NULL;
HEIMDAL_MUTEX_lock(&tls_key_defs_lock);
key_defs = tls_key_defs;
HEIMDAL_MUTEX_unlock(&tls_key_defs_lock);
while (key_defs != NULL) {
if (key >= key_defs->keys_start_idx &&
key < key_defs->keys_start_idx + key_defs->keys_num) {
if (kd != NULL)
*kd = key_defs;
if (dtor_idx != NULL)
*dtor_idx = key - key_defs->keys_start_idx;
if (dtor != NULL)
*dtor = key_defs->keys_dtors[key - key_defs->keys_start_idx];
return;
}
HEIMDAL_MUTEX_lock(&tls_key_defs_lock);
key_defs = key_defs->keys_next;
HEIMDAL_MUTEX_unlock(&tls_key_defs_lock);
assert(key_defs != NULL);
assert(key >= key_defs->keys_start_idx);
}
}
int
heim_w32_delete_key(HEIM_PRIV_thread_key key)
{
tls_keys *key_defs;
size_t dtor_idx;
key_lookup(key, &key_defs, &dtor_idx, NULL);
if (key_defs == NULL)
return EINVAL;
key_defs->keys_dtors[dtor_idx] = DEAD_KEY;
return 0;
}
int
heim_w32_setspecific(HEIM_PRIV_thread_key key, void *value)
{
void **new_values;
size_t new_num;
void (*dtor)(void *);
size_t i;
#if !defined(WIN32)
(void) pthread_setspecific(pt_key, DEAD_KEY);
#endif
key_lookup(key, NULL, NULL, &dtor);
if (dtor == NULL)
return EINVAL;
if (key >= values.values_num) {
if (values.values_num == 0) {
values.values = NULL;
new_num = 8;
} else {
new_num = (values.values_num + values.values_num / 2);
}
new_values = realloc(values.values, sizeof(void *) * new_num);
if (new_values == NULL)
return ENOMEM;
for (i = values.values_num; i < new_num; i++)
new_values[i] = NULL;
values.values = new_values;
values.values_num = new_num;
}
assert(key < values.values_num);
if (values.values[key] != NULL && dtor != NULL && dtor != DEAD_KEY)
dtor(values.values[key]);
values.values[key] = value;
return 0;
}
void *
heim_w32_getspecific(HEIM_PRIV_thread_key key)
{
if (key >= values.values_num)
return NULL;
return values.values[key];
}
#ifdef WIN32
BOOL WINAPI DllMain(HINSTANCE hinstDLL,
DWORD fdwReason,
LPVOID lpvReserved)
{
switch (fdwReason) {
case DLL_PROCESS_ATTACH:
return TRUE;
case DLL_PROCESS_DETACH:
return FALSE;
case DLL_THREAD_ATTACH:
return FALSE;
case DLL_THREAD_DETACH:
del_tls_for_thread(NULL);
return FALSE;
}
return FALSE;
}
#endif /* WIN32 */
#else
static char dummy;
#endif /* HEIM_WIN32_TLS */