2 * Copyright 2016-2024 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
12 # if defined(_WIN32_WINNT) && _WIN32_WINNT >= 0x600
19 * VC++ 2008 or earlier x86 compilers do not have an inline implementation
20 * of InterlockedOr64 for 32bit and will fail to run on Windows XP 32bit.
21 * https://docs.microsoft.com/en-us/cpp/intrinsics/interlockedor-intrinsic-functions#requirements
22 * To work around this problem, we implement a manual locking mechanism for
23 * only VC++ 2008 or earlier x86 compilers.
26 #if (defined(_MSC_VER) && defined(_M_IX86) && _MSC_VER <= 1600)
27 # define NO_INTERLOCKEDOR64
30 #include <openssl/crypto.h>
31 #include <crypto/cryptlib.h>
32 #include "internal/common.h"
33 #include "internal/thread_arch.h"
34 #include "internal/rcu.h"
35 #include "rcu_internal.h"
37 #if defined(OPENSSL_THREADS) && !defined(CRYPTO_TDEBUG) && defined(OPENSSL_SYS_WINDOWS)
46 # define READER_SHIFT 0
48 # define READER_SIZE 32
51 # define READER_MASK (((LONG64)1 << READER_SIZE)-1)
52 # define ID_MASK (((LONG64)1 << ID_SIZE)-1)
53 # define READER_COUNT(x) (((LONG64)(x) >> READER_SHIFT) & READER_MASK)
54 # define ID_VAL(x) (((LONG64)(x) >> ID_SHIFT) & ID_MASK)
55 # define VAL_READER ((LONG64)1 << READER_SHIFT)
56 # define VAL_ID(x) ((LONG64)x << ID_SHIFT)
59 * This defines a quescent point (qp)
60 * This is the barrier beyond which a writer
61 * must wait before freeing data that was
65 volatile LONG64 users;
71 CRYPTO_RCU_LOCK *lock;
76 * This is the per thread tracking data
77 * that is assigned to each thread participating
80 * qp points to the qp that it last acquired
84 struct thread_qp thread_qps[MAX_QPS];
88 * This is the internal version of a CRYPTO_RCU_LOCK
89 * it is cast from CRYPTO_RCU_LOCK
92 struct rcu_cb_item *cb_items;
95 struct rcu_qp *qp_group;
97 uint32_t next_to_retire;
98 volatile long int reader_idx;
99 uint32_t current_alloc_idx;
100 uint32_t writers_alloced;
101 CRYPTO_MUTEX *write_lock;
102 CRYPTO_MUTEX *alloc_lock;
103 CRYPTO_CONDVAR *alloc_signal;
104 CRYPTO_MUTEX *prior_lock;
105 CRYPTO_CONDVAR *prior_signal;
108 static struct rcu_qp *allocate_new_qp_group(struct rcu_lock_st *lock,
112 OPENSSL_zalloc(sizeof(*new) * count);
114 lock->group_count = count;
118 CRYPTO_RCU_LOCK *ossl_rcu_lock_new(int num_writers, OSSL_LIB_CTX *ctx)
120 struct rcu_lock_st *new;
125 ctx = ossl_lib_ctx_get_concrete(ctx);
129 new = OPENSSL_zalloc(sizeof(*new));
135 new->write_lock = ossl_crypto_mutex_new();
136 new->alloc_signal = ossl_crypto_condvar_new();
137 new->prior_signal = ossl_crypto_condvar_new();
138 new->alloc_lock = ossl_crypto_mutex_new();
139 new->prior_lock = ossl_crypto_mutex_new();
140 new->qp_group = allocate_new_qp_group(new, num_writers + 1);
141 if (new->qp_group == NULL
142 || new->alloc_signal == NULL
143 || new->prior_signal == NULL
144 || new->write_lock == NULL
145 || new->alloc_lock == NULL
146 || new->prior_lock == NULL) {
147 OPENSSL_free(new->qp_group);
148 ossl_crypto_condvar_free(&new->alloc_signal);
149 ossl_crypto_condvar_free(&new->prior_signal);
150 ossl_crypto_mutex_free(&new->alloc_lock);
151 ossl_crypto_mutex_free(&new->prior_lock);
152 ossl_crypto_mutex_free(&new->write_lock);
160 void ossl_rcu_lock_free(CRYPTO_RCU_LOCK *lock)
162 OPENSSL_free(lock->qp_group);
163 ossl_crypto_condvar_free(&lock->alloc_signal);
164 ossl_crypto_condvar_free(&lock->prior_signal);
165 ossl_crypto_mutex_free(&lock->alloc_lock);
166 ossl_crypto_mutex_free(&lock->prior_lock);
167 ossl_crypto_mutex_free(&lock->write_lock);
171 static inline struct rcu_qp *get_hold_current_qp(CRYPTO_RCU_LOCK *lock)
175 /* get the current qp index */
177 qp_idx = InterlockedOr(&lock->reader_idx, 0);
178 InterlockedAdd64(&lock->qp_group[qp_idx].users, VAL_READER);
179 if (qp_idx == InterlockedOr(&lock->reader_idx, 0))
181 InterlockedAdd64(&lock->qp_group[qp_idx].users, -VAL_READER);
184 return &lock->qp_group[qp_idx];
187 static void ossl_rcu_free_local_data(void *arg)
189 OSSL_LIB_CTX *ctx = arg;
190 CRYPTO_THREAD_LOCAL *lkey = ossl_lib_ctx_get_rcukey(ctx);
191 struct rcu_thr_data *data = CRYPTO_THREAD_get_local(lkey);
195 void ossl_rcu_read_lock(CRYPTO_RCU_LOCK *lock)
197 struct rcu_thr_data *data;
199 int available_qp = -1;
200 CRYPTO_THREAD_LOCAL *lkey = ossl_lib_ctx_get_rcukey(lock->ctx);
203 * we're going to access current_qp here so ask the
204 * processor to fetch it
206 data = CRYPTO_THREAD_get_local(lkey);
209 data = OPENSSL_zalloc(sizeof(*data));
210 OPENSSL_assert(data != NULL);
211 CRYPTO_THREAD_set_local(lkey, data);
212 ossl_init_thread_start(NULL, lock->ctx, ossl_rcu_free_local_data);
215 for (i = 0; i < MAX_QPS; i++) {
216 if (data->thread_qps[i].qp == NULL && available_qp == -1)
218 /* If we have a hold on this lock already, we're good */
219 if (data->thread_qps[i].lock == lock)
224 * if we get here, then we don't have a hold on this lock yet
226 assert(available_qp != -1);
228 data->thread_qps[available_qp].qp = get_hold_current_qp(lock);
229 data->thread_qps[available_qp].depth = 1;
230 data->thread_qps[available_qp].lock = lock;
233 void ossl_rcu_write_lock(CRYPTO_RCU_LOCK *lock)
235 ossl_crypto_mutex_lock(lock->write_lock);
238 void ossl_rcu_write_unlock(CRYPTO_RCU_LOCK *lock)
240 ossl_crypto_mutex_unlock(lock->write_lock);
243 void ossl_rcu_read_unlock(CRYPTO_RCU_LOCK *lock)
245 CRYPTO_THREAD_LOCAL *lkey = ossl_lib_ctx_get_rcukey(lock->ctx);
246 struct rcu_thr_data *data = CRYPTO_THREAD_get_local(lkey);
250 assert(data != NULL);
252 for (i = 0; i < MAX_QPS; i++) {
253 if (data->thread_qps[i].lock == lock) {
254 data->thread_qps[i].depth--;
255 if (data->thread_qps[i].depth == 0) {
256 ret = InterlockedAdd64(&data->thread_qps[i].qp->users, -VAL_READER);
257 OPENSSL_assert(ret >= 0);
258 data->thread_qps[i].qp = NULL;
259 data->thread_qps[i].lock = NULL;
266 static struct rcu_qp *update_qp(CRYPTO_RCU_LOCK *lock)
269 uint32_t current_idx;
272 ossl_crypto_mutex_lock(lock->alloc_lock);
274 * we need at least one qp to be available with one
275 * left over, so that readers can start working on
276 * one that isn't yet being waited on
278 while (lock->group_count - lock->writers_alloced < 2)
279 ossl_crypto_condvar_wait(lock->alloc_signal, lock->alloc_lock);
281 current_idx = lock->current_alloc_idx;
282 /* Allocate the qp */
283 lock->writers_alloced++;
285 /* increment the allocation index */
286 lock->current_alloc_idx =
287 (lock->current_alloc_idx + 1) % lock->group_count;
289 /* get and insert a new id */
290 new_id = lock->id_ctr;
293 new_id = VAL_ID(new_id);
294 InterlockedAnd64(&lock->qp_group[current_idx].users, ID_MASK);
295 InterlockedAdd64(&lock->qp_group[current_idx].users, new_id);
297 /* update the reader index to be the prior qp */
298 tmp = lock->current_alloc_idx;
299 InterlockedExchange(&lock->reader_idx, tmp);
301 /* wake up any waiters */
302 ossl_crypto_condvar_broadcast(lock->alloc_signal);
303 ossl_crypto_mutex_unlock(lock->alloc_lock);
304 return &lock->qp_group[current_idx];
307 static void retire_qp(CRYPTO_RCU_LOCK *lock,
310 ossl_crypto_mutex_lock(lock->alloc_lock);
311 lock->writers_alloced--;
312 ossl_crypto_condvar_broadcast(lock->alloc_signal);
313 ossl_crypto_mutex_unlock(lock->alloc_lock);
317 void ossl_synchronize_rcu(CRYPTO_RCU_LOCK *lock)
321 struct rcu_cb_item *cb_items, *tmpcb;
323 /* before we do anything else, lets grab the cb list */
324 cb_items = InterlockedExchangePointer((void * volatile *)&lock->cb_items, NULL);
326 qp = update_qp(lock);
328 /* wait for the reader count to reach zero */
330 count = InterlockedOr64(&qp->users, 0);
331 } while (READER_COUNT(count) != 0);
333 /* retire in order */
334 ossl_crypto_mutex_lock(lock->prior_lock);
335 while (lock->next_to_retire != ID_VAL(count))
336 ossl_crypto_condvar_wait(lock->prior_signal, lock->prior_lock);
338 lock->next_to_retire++;
339 ossl_crypto_condvar_broadcast(lock->prior_signal);
340 ossl_crypto_mutex_unlock(lock->prior_lock);
344 /* handle any callbacks that we have */
345 while (cb_items != NULL) {
347 cb_items = cb_items->next;
348 tmpcb->fn(tmpcb->data);
357 int ossl_rcu_call(CRYPTO_RCU_LOCK *lock, rcu_cb_fn cb, void *data)
359 struct rcu_cb_item *new;
360 struct rcu_cb_item *prev;
362 new = OPENSSL_zalloc(sizeof(struct rcu_cb_item));
369 InterlockedExchangePointer((void * volatile *)&lock->cb_items, prev);
374 void *ossl_rcu_uptr_deref(void **p)
379 void ossl_rcu_assign_uptr(void **p, void **v)
381 InterlockedExchangePointer((void * volatile *)p, (void *)*v);
385 CRYPTO_RWLOCK *CRYPTO_THREAD_lock_new(void)
389 CRYPTO_win_rwlock *rwlock;
391 if ((lock = OPENSSL_zalloc(sizeof(CRYPTO_win_rwlock))) == NULL)
392 /* Don't set error, to avoid recursion blowup. */
395 InitializeSRWLock(&rwlock->lock);
398 if ((lock = OPENSSL_zalloc(sizeof(CRITICAL_SECTION))) == NULL)
399 /* Don't set error, to avoid recursion blowup. */
402 # if !defined(_WIN32_WCE)
403 /* 0x400 is the spin count value suggested in the documentation */
404 if (!InitializeCriticalSectionAndSpinCount(lock, 0x400)) {
409 InitializeCriticalSection(lock);
416 __owur int CRYPTO_THREAD_read_lock(CRYPTO_RWLOCK *lock)
419 CRYPTO_win_rwlock *rwlock = lock;
421 AcquireSRWLockShared(&rwlock->lock);
423 EnterCriticalSection(lock);
428 __owur int CRYPTO_THREAD_write_lock(CRYPTO_RWLOCK *lock)
431 CRYPTO_win_rwlock *rwlock = lock;
433 AcquireSRWLockExclusive(&rwlock->lock);
434 rwlock->exclusive = 1;
436 EnterCriticalSection(lock);
441 int CRYPTO_THREAD_unlock(CRYPTO_RWLOCK *lock)
444 CRYPTO_win_rwlock *rwlock = lock;
446 if (rwlock->exclusive) {
447 rwlock->exclusive = 0;
448 ReleaseSRWLockExclusive(&rwlock->lock);
450 ReleaseSRWLockShared(&rwlock->lock);
453 LeaveCriticalSection(lock);
458 void CRYPTO_THREAD_lock_free(CRYPTO_RWLOCK *lock)
464 DeleteCriticalSection(lock);
471 # define ONCE_UNINITED 0
472 # define ONCE_ININIT 1
476 * We don't use InitOnceExecuteOnce because that isn't available in WinXP which
477 * we still have to support.
479 int CRYPTO_THREAD_run_once(CRYPTO_ONCE *once, void (*init)(void))
481 LONG volatile *lock = (LONG *)once;
484 if (*lock == ONCE_DONE)
488 result = InterlockedCompareExchange(lock, ONCE_ININIT, ONCE_UNINITED);
489 if (result == ONCE_UNINITED) {
494 } while (result == ONCE_ININIT);
496 return (*lock == ONCE_DONE);
499 int CRYPTO_THREAD_init_local(CRYPTO_THREAD_LOCAL *key, void (*cleanup)(void *))
502 if (*key == TLS_OUT_OF_INDEXES)
508 void *CRYPTO_THREAD_get_local(CRYPTO_THREAD_LOCAL *key)
514 * TlsGetValue clears the last error even on success, so that callers may
515 * distinguish it successfully returning NULL or failing. It is documented
516 * to never fail if the argument is a valid index from TlsAlloc, so we do
517 * not need to handle this.
519 * However, this error-mangling behavior interferes with the caller's use of
520 * GetLastError. In particular SSL_get_error queries the error queue to
521 * determine whether the caller should look at the OS's errors. To avoid
522 * destroying state, save and restore the Windows error.
524 * https://msdn.microsoft.com/en-us/library/windows/desktop/ms686812(v=vs.85).aspx
526 last_error = GetLastError();
527 ret = TlsGetValue(*key);
528 SetLastError(last_error);
532 int CRYPTO_THREAD_set_local(CRYPTO_THREAD_LOCAL *key, void *val)
534 if (TlsSetValue(*key, val) == 0)
540 int CRYPTO_THREAD_cleanup_local(CRYPTO_THREAD_LOCAL *key)
542 if (TlsFree(*key) == 0)
548 CRYPTO_THREAD_ID CRYPTO_THREAD_get_current_id(void)
550 return GetCurrentThreadId();
553 int CRYPTO_THREAD_compare_id(CRYPTO_THREAD_ID a, CRYPTO_THREAD_ID b)
558 int CRYPTO_atomic_add(int *val, int amount, int *ret, CRYPTO_RWLOCK *lock)
560 *ret = (int)InterlockedExchangeAdd((long volatile *)val, (long)amount) + amount;
564 int CRYPTO_atomic_or(uint64_t *val, uint64_t op, uint64_t *ret,
567 #if (defined(NO_INTERLOCKEDOR64))
568 if (lock == NULL || !CRYPTO_THREAD_write_lock(lock))
573 if (!CRYPTO_THREAD_unlock(lock))
578 *ret = (uint64_t)InterlockedOr64((LONG64 volatile *)val, (LONG64)op) | op;
583 int CRYPTO_atomic_load(uint64_t *val, uint64_t *ret, CRYPTO_RWLOCK *lock)
585 #if (defined(NO_INTERLOCKEDOR64))
586 if (lock == NULL || !CRYPTO_THREAD_read_lock(lock))
589 if (!CRYPTO_THREAD_unlock(lock))
594 *ret = (uint64_t)InterlockedOr64((LONG64 volatile *)val, 0);
599 int CRYPTO_atomic_load_int(int *val, int *ret, CRYPTO_RWLOCK *lock)
601 #if (defined(NO_INTERLOCKEDOR64))
602 if (lock == NULL || !CRYPTO_THREAD_read_lock(lock))
605 if (!CRYPTO_THREAD_unlock(lock))
610 /* On Windows, LONG is always the same size as int. */
611 *ret = (int)InterlockedOr((LONG volatile *)val, 0);
616 int openssl_init_fork_handlers(void)
621 int openssl_get_fork_id(void)