Replace CRYPTO_once_t on Windows with INIT_ONCE.
Now that we no longer support Windows XP, this function is available. In doing
so, remove the odd run_once_arg_t union and pass in a pointer to a function
pointer which is cleaner and still avoids C's silly rule where function
pointers can't be placed in a void*.
BUG=37
Change-Id: I44888bb3779dacdb660706debd33888ca389ebd5
Reviewed-on: https://boringssl-review.googlesource.com/7613
Reviewed-by: David Benjamin <davidben@google.com>
diff --git a/crypto/thread_win.c b/crypto/thread_win.c
index 8e231eb..2632565 100644
--- a/crypto/thread_win.c
+++ b/crypto/thread_win.c
@@ -20,7 +20,6 @@
#include <windows.h>
#pragma warning(pop)
-#include <assert.h>
#include <stdlib.h>
#include <string.h>
@@ -31,61 +30,16 @@
OPENSSL_COMPILE_ASSERT(sizeof(CRYPTO_MUTEX) >= sizeof(CRITICAL_SECTION),
CRYPTO_MUTEX_too_small);
-union run_once_arg_t {
- void (*func)(void);
- void *data;
-};
-
-static void run_once(CRYPTO_once_t *once, void (*init)(union run_once_arg_t),
- union run_once_arg_t arg) {
- /* 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(arg);
- /* 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 BOOL CALLBACK call_once_init(INIT_ONCE *once, void *arg, void **out) {
+ void (**init)(void) = (void (**)(void))arg;
+ (**init)();
+ return TRUE;
}
-static void call_once_init(union run_once_arg_t arg) {
- arg.func();
-}
-
-void CRYPTO_once(CRYPTO_once_t *in_once, void (*init)(void)) {
- union run_once_arg_t arg;
- arg.func = init;
- run_once(in_once, call_once_init, arg);
+void CRYPTO_once(CRYPTO_once_t *once, void (*init)(void)) {
+ if (!InitOnceExecuteOnce(once, call_once_init, &init, NULL)) {
+ abort();
+ }
}
void CRYPTO_MUTEX_init(CRYPTO_MUTEX *lock) {
@@ -111,18 +65,21 @@
DeleteCriticalSection((CRITICAL_SECTION *) lock);
}
-static void static_lock_init(union run_once_arg_t arg) {
- struct CRYPTO_STATIC_MUTEX *lock = arg.data;
+static BOOL CALLBACK static_lock_init(INIT_ONCE *once, void *arg, void **out) {
+ struct CRYPTO_STATIC_MUTEX *lock = arg;
if (!InitializeCriticalSectionAndSpinCount(&lock->lock, 0x400)) {
abort();
}
+ return TRUE;
}
void CRYPTO_STATIC_MUTEX_lock_read(struct CRYPTO_STATIC_MUTEX *lock) {
- union run_once_arg_t arg;
- arg.data = lock;
- /* Since we have to support Windows XP, read locks are actually exclusive. */
- run_once(&lock->once, static_lock_init, arg);
+ /* TODO(davidben): Consider replacing these with SRWLOCK now that we no longer
+ * need to support Windows XP. Currently, read locks are actually
+ * exclusive. */
+ if (!InitOnceExecuteOnce(&lock->once, static_lock_init, lock, NULL)) {
+ abort();
+ }
EnterCriticalSection(&lock->lock);
}
