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/* Copyright (c) 2015, Google Inc.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
#include "internal.h"
#if defined(OPENSSL_WINDOWS)
#pragma warning(push, 3)
#include <windows.h>
#pragma warning(pop)
#include <assert.h>
#include <string.h>
#include <openssl/mem.h>
void CRYPTO_once(CRYPTO_once_t *in_once, void (*init)(void)) {
volatile LONG *once = (LONG*) in_once;
assert(sizeof(LONG) == sizeof(CRYPTO_once_t));
/* Values must be aligned. */
assert((((uintptr_t) once) & 3) == 0);
/* This assumes that reading *once has acquire semantics. This should be true
* on x86 and x86-64, where we expect Windows to run. */
#if !defined(OPENSSL_X86) && !defined(OPENSSL_X86_64)
#error "Windows once code may not work on other platforms." \
"You can use InitOnceBeginInitialize on >=Vista"
#endif
if (*once == 1) {
return;
}
for (;;) {
switch (InterlockedCompareExchange(once, 2, 0)) {
case 0:
/* The value was zero so we are the first thread to call |CRYPTO_once|
* on it. */
init();
/* Write one to indicate that initialisation is complete. */
InterlockedExchange(once, 1);
return;
case 1:
/* Another thread completed initialisation between our fast-path check
* and |InterlockedCompareExchange|. */
return;
case 2:
/* Another thread is running the initialisation. Switch to it then try
* again. */
SwitchToThread();
break;
default:
abort();
}
}
}
static CRITICAL_SECTION g_destructors_lock;
static thread_local_destructor_t g_destructors[NUM_OPENSSL_THREAD_LOCALS];
static CRYPTO_once_t g_thread_local_init_once = CRYPTO_ONCE_INIT;
static DWORD g_thread_local_key;
static int g_thread_local_failed;
static void thread_local_init(void) {
if (!InitializeCriticalSectionAndSpinCount(&g_destructors_lock, 0x400)) {
g_thread_local_failed = 1;
return;
}
g_thread_local_key = TlsAlloc();
g_thread_local_failed = (g_thread_local_key == TLS_OUT_OF_INDEXES);
}
static void NTAPI thread_local_destructor(PVOID module,
DWORD reason, PVOID reserved) {
if (DLL_THREAD_DETACH != reason && DLL_PROCESS_DETACH != reason) {
return;
}
CRYPTO_once(&g_thread_local_init_once, thread_local_init);
if (g_thread_local_failed) {
return;
}
void **pointers = (void**) TlsGetValue(g_thread_local_key);
if (pointers == NULL) {
return;
}
thread_local_destructor_t destructors[NUM_OPENSSL_THREAD_LOCALS];
EnterCriticalSection(&g_destructors_lock);
memcpy(destructors, g_destructors, sizeof(destructors));
LeaveCriticalSection(&g_destructors_lock);
unsigned i;
for (i = 0; i < NUM_OPENSSL_THREAD_LOCALS; i++) {
if (destructors[i] != NULL) {
destructors[i](pointers[i]);
}
}
OPENSSL_free(pointers);
}
/* Thread Termination Callbacks.
*
* Windows doesn't support a per-thread destructor with its TLS primitives.
* So, we build it manually by inserting a function to be called on each
* thread's exit. This magic is from http://www.codeproject.com/threads/tls.asp
* and it works for VC++ 7.0 and later.
*
* Force a reference to _tls_used to make the linker create the TLS directory
* if it's not already there. (E.g. if __declspec(thread) is not used). Force
* a reference to p_thread_callback_boringssl to prevent whole program
* optimization from discarding the variable. */
#ifdef _WIN64
#pragma comment(linker, "/INCLUDE:_tls_used")
#pragma comment(linker, "/INCLUDE:p_thread_callback_boringssl")
#else
#pragma comment(linker, "/INCLUDE:__tls_used")
#pragma comment(linker, "/INCLUDE:_p_thread_callback_boringssl")
#endif
/* .CRT$XLA to .CRT$XLZ is an array of PIMAGE_TLS_CALLBACK pointers that are
* called automatically by the OS loader code (not the CRT) when the module is
* loaded and on thread creation. They are NOT called if the module has been
* loaded by a LoadLibrary() call. It must have implicitly been loaded at
* process startup.
*
* By implicitly loaded, I mean that it is directly referenced by the main EXE
* or by one of its dependent DLLs. Delay-loaded DLL doesn't count as being
* implicitly loaded.
*
* See VC\crt\src\tlssup.c for reference. */
/* The linker must not discard p_thread_callback_boringssl. (We force a reference
* to this variable with a linker /INCLUDE:symbol pragma to ensure that.) If
* this variable is discarded, the OnThreadExit function will never be
* called. */
#ifdef _WIN64
/* .CRT section is merged with .rdata on x64 so it must be constant data. */
#pragma const_seg(".CRT$XLC")
/* When defining a const variable, it must have external linkage to be sure the
* linker doesn't discard it. */
extern const PIMAGE_TLS_CALLBACK p_thread_callback_boringssl;
const PIMAGE_TLS_CALLBACK p_thread_callback_boringssl = thread_local_destructor;
/* Reset the default section. */
#pragma const_seg()
#else
#pragma data_seg(".CRT$XLC")
PIMAGE_TLS_CALLBACK p_thread_callback_boringssl = thread_local_destructor;
/* Reset the default section. */
#pragma data_seg()
#endif /* _WIN64 */
void *CRYPTO_get_thread_local(thread_local_data_t index) {
CRYPTO_once(&g_thread_local_init_once, thread_local_init);
if (g_thread_local_failed) {
return NULL;
}
void **pointers = TlsGetValue(g_thread_local_key);
if (pointers == NULL) {
return NULL;
}
return pointers[index];
}
int CRYPTO_set_thread_local(thread_local_data_t index, void *value,
thread_local_destructor_t destructor) {
CRYPTO_once(&g_thread_local_init_once, thread_local_init);
if (g_thread_local_failed) {
destructor(value);
return 0;
}
void **pointers = TlsGetValue(g_thread_local_key);
if (pointers == NULL) {
pointers = OPENSSL_malloc(sizeof(void *) * NUM_OPENSSL_THREAD_LOCALS);
if (pointers == NULL) {
destructor(value);
return 0;
}
memset(pointers, 0, sizeof(void *) * NUM_OPENSSL_THREAD_LOCALS);
if (TlsSetValue(g_thread_local_key, pointers) == 0) {
OPENSSL_free(pointers);
destructor(value);
return 0;
}
}
EnterCriticalSection(&g_destructors_lock);
g_destructors[index] = destructor;
LeaveCriticalSection(&g_destructors_lock);
pointers[index] = value;
return 1;
}
#endif /* OPENSSL_WINDOWS */