diff options
Diffstat (limited to 'crypto/threads_pthread.c')
| -rw-r--r-- | crypto/threads_pthread.c | 649 |
1 files changed, 640 insertions, 9 deletions
diff --git a/crypto/threads_pthread.c b/crypto/threads_pthread.c index 801855c9306e..750ef201210b 100644 --- a/crypto/threads_pthread.c +++ b/crypto/threads_pthread.c @@ -1,5 +1,5 @@ /* - * Copyright 2016-2023 The OpenSSL Project Authors. All Rights Reserved. + * Copyright 2016-2025 The OpenSSL Project Authors. All Rights Reserved. * * Licensed under the Apache License 2.0 (the "License"). You may not use * this file except in compliance with the License. You can obtain a copy @@ -11,7 +11,28 @@ #define OPENSSL_SUPPRESS_DEPRECATED #include <openssl/crypto.h> +#include <crypto/cryptlib.h> #include "internal/cryptlib.h" +#include "internal/rcu.h" +#include "rcu_internal.h" + +#if defined(__clang__) && defined(__has_feature) +# if __has_feature(thread_sanitizer) +# define __SANITIZE_THREAD__ +# endif +#endif + +#if defined(__SANITIZE_THREAD__) +# include <sanitizer/tsan_interface.h> +# define TSAN_FAKE_UNLOCK(x) __tsan_mutex_pre_unlock((x), 0); \ +__tsan_mutex_post_unlock((x), 0) + +# define TSAN_FAKE_LOCK(x) __tsan_mutex_pre_lock((x), 0); \ +__tsan_mutex_post_lock((x), 0, 0) +#else +# define TSAN_FAKE_UNLOCK(x) +# define TSAN_FAKE_LOCK(x) +#endif #if defined(__sun) # include <atomic.h> @@ -26,7 +47,7 @@ * * See: https://github.com/llvm/llvm-project/commit/a4c2602b714e6c6edb98164550a5ae829b2de760 */ -#define BROKEN_CLANG_ATOMICS +# define BROKEN_CLANG_ATOMICS #endif #if defined(OPENSSL_THREADS) && !defined(CRYPTO_TDEBUG) && !defined(OPENSSL_SYS_WINDOWS) @@ -34,23 +55,535 @@ # if defined(OPENSSL_SYS_UNIX) # include <sys/types.h> # include <unistd.h> -#endif +# endif # include <assert.h> -# ifdef PTHREAD_RWLOCK_INITIALIZER +/* + * The Non-Stop KLT thread model currently seems broken in its rwlock + * implementation + */ +# if defined(PTHREAD_RWLOCK_INITIALIZER) && !defined(_KLT_MODEL_) # define USE_RWLOCK # endif +/* + * For all GNU/clang atomic builtins, we also need fallbacks, to cover all + * other compilers. + + * Unfortunately, we can't do that with some "generic type", because there's no + * guarantee that the chosen generic type is large enough to cover all cases. + * Therefore, we implement fallbacks for each applicable type, with composed + * names that include the type they handle. + * + * (an anecdote: we previously tried to use |void *| as the generic type, with + * the thought that the pointer itself is the largest type. However, this is + * not true on 32-bit pointer platforms, as a |uint64_t| is twice as large) + * + * All applicable ATOMIC_ macros take the intended type as first parameter, so + * they can map to the correct fallback function. In the GNU/clang case, that + * parameter is simply ignored. + */ + +/* + * Internal types used with the ATOMIC_ macros, to make it possible to compose + * fallback function names. + */ +typedef void *pvoid; + +# if defined(__GNUC__) && defined(__ATOMIC_ACQUIRE) && !defined(BROKEN_CLANG_ATOMICS) \ + && !defined(USE_ATOMIC_FALLBACKS) +# define ATOMIC_LOAD_N(t, p, o) __atomic_load_n(p, o) +# define ATOMIC_STORE_N(t, p, v, o) __atomic_store_n(p, v, o) +# define ATOMIC_STORE(t, p, v, o) __atomic_store(p, v, o) +# define ATOMIC_ADD_FETCH(p, v, o) __atomic_add_fetch(p, v, o) +# define ATOMIC_SUB_FETCH(p, v, o) __atomic_sub_fetch(p, v, o) +# else +static pthread_mutex_t atomic_sim_lock = PTHREAD_MUTEX_INITIALIZER; + +# define IMPL_fallback_atomic_load_n(t) \ + static ossl_inline t fallback_atomic_load_n_##t(t *p) \ + { \ + t ret; \ + \ + pthread_mutex_lock(&atomic_sim_lock); \ + ret = *p; \ + pthread_mutex_unlock(&atomic_sim_lock); \ + return ret; \ + } +IMPL_fallback_atomic_load_n(uint32_t) +IMPL_fallback_atomic_load_n(uint64_t) +IMPL_fallback_atomic_load_n(pvoid) + +# define ATOMIC_LOAD_N(t, p, o) fallback_atomic_load_n_##t(p) + +# define IMPL_fallback_atomic_store_n(t) \ + static ossl_inline t fallback_atomic_store_n_##t(t *p, t v) \ + { \ + t ret; \ + \ + pthread_mutex_lock(&atomic_sim_lock); \ + ret = *p; \ + *p = v; \ + pthread_mutex_unlock(&atomic_sim_lock); \ + return ret; \ + } +IMPL_fallback_atomic_store_n(uint32_t) + +# define ATOMIC_STORE_N(t, p, v, o) fallback_atomic_store_n_##t(p, v) + +# define IMPL_fallback_atomic_store(t) \ + static ossl_inline void fallback_atomic_store_##t(t *p, t *v) \ + { \ + pthread_mutex_lock(&atomic_sim_lock); \ + *p = *v; \ + pthread_mutex_unlock(&atomic_sim_lock); \ + } +IMPL_fallback_atomic_store(pvoid) + +# define ATOMIC_STORE(t, p, v, o) fallback_atomic_store_##t(p, v) + +/* + * The fallbacks that follow don't need any per type implementation, as + * they are designed for uint64_t only. If there comes a time when multiple + * types need to be covered, it's relatively easy to refactor them the same + * way as the fallbacks above. + */ + +static ossl_inline uint64_t fallback_atomic_add_fetch(uint64_t *p, uint64_t v) +{ + uint64_t ret; + + pthread_mutex_lock(&atomic_sim_lock); + *p += v; + ret = *p; + pthread_mutex_unlock(&atomic_sim_lock); + return ret; +} + +# define ATOMIC_ADD_FETCH(p, v, o) fallback_atomic_add_fetch(p, v) + +static ossl_inline uint64_t fallback_atomic_sub_fetch(uint64_t *p, uint64_t v) +{ + uint64_t ret; + + pthread_mutex_lock(&atomic_sim_lock); + *p -= v; + ret = *p; + pthread_mutex_unlock(&atomic_sim_lock); + return ret; +} + +# define ATOMIC_SUB_FETCH(p, v, o) fallback_atomic_sub_fetch(p, v) +# endif + +/* + * This is the core of an rcu lock. It tracks the readers and writers for the + * current quiescence point for a given lock. Users is the 64 bit value that + * stores the READERS/ID as defined above + * + */ +struct rcu_qp { + uint64_t users; +}; + +struct thread_qp { + struct rcu_qp *qp; + unsigned int depth; + CRYPTO_RCU_LOCK *lock; +}; + +# define MAX_QPS 10 +/* + * This is the per thread tracking data + * that is assigned to each thread participating + * in an rcu qp + * + * qp points to the qp that it last acquired + * + */ +struct rcu_thr_data { + struct thread_qp thread_qps[MAX_QPS]; +}; + +/* + * This is the internal version of a CRYPTO_RCU_LOCK + * it is cast from CRYPTO_RCU_LOCK + */ +struct rcu_lock_st { + /* Callbacks to call for next ossl_synchronize_rcu */ + struct rcu_cb_item *cb_items; + + /* The context we are being created against */ + OSSL_LIB_CTX *ctx; + + /* Array of quiescent points for synchronization */ + struct rcu_qp *qp_group; + + /* rcu generation counter for in-order retirement */ + uint32_t id_ctr; + + /* Number of elements in qp_group array */ + uint32_t group_count; + + /* Index of the current qp in the qp_group array */ + uint32_t reader_idx; + + /* value of the next id_ctr value to be retired */ + uint32_t next_to_retire; + + /* index of the next free rcu_qp in the qp_group */ + uint32_t current_alloc_idx; + + /* number of qp's in qp_group array currently being retired */ + uint32_t writers_alloced; + + /* lock protecting write side operations */ + pthread_mutex_t write_lock; + + /* lock protecting updates to writers_alloced/current_alloc_idx */ + pthread_mutex_t alloc_lock; + + /* signal to wake threads waiting on alloc_lock */ + pthread_cond_t alloc_signal; + + /* lock to enforce in-order retirement */ + pthread_mutex_t prior_lock; + + /* signal to wake threads waiting on prior_lock */ + pthread_cond_t prior_signal; +}; + +/* Read side acquisition of the current qp */ +static struct rcu_qp *get_hold_current_qp(struct rcu_lock_st *lock) +{ + uint32_t qp_idx; + + /* get the current qp index */ + for (;;) { + qp_idx = ATOMIC_LOAD_N(uint32_t, &lock->reader_idx, __ATOMIC_RELAXED); + + /* + * Notes on use of __ATOMIC_ACQUIRE + * We need to ensure the following: + * 1) That subsequent operations aren't optimized by hoisting them above + * this operation. Specifically, we don't want the below re-load of + * qp_idx to get optimized away + * 2) We want to ensure that any updating of reader_idx on the write side + * of the lock is flushed from a local cpu cache so that we see any + * updates prior to the load. This is a non-issue on cache coherent + * systems like x86, but is relevant on other arches + */ + ATOMIC_ADD_FETCH(&lock->qp_group[qp_idx].users, (uint64_t)1, + __ATOMIC_ACQUIRE); + + /* if the idx hasn't changed, we're good, else try again */ + if (qp_idx == ATOMIC_LOAD_N(uint32_t, &lock->reader_idx, + __ATOMIC_RELAXED)) + break; + + ATOMIC_SUB_FETCH(&lock->qp_group[qp_idx].users, (uint64_t)1, + __ATOMIC_RELAXED); + } + + return &lock->qp_group[qp_idx]; +} + +static void ossl_rcu_free_local_data(void *arg) +{ + OSSL_LIB_CTX *ctx = arg; + CRYPTO_THREAD_LOCAL *lkey = ossl_lib_ctx_get_rcukey(ctx); + struct rcu_thr_data *data = CRYPTO_THREAD_get_local(lkey); + + OPENSSL_free(data); + CRYPTO_THREAD_set_local(lkey, NULL); +} + +void ossl_rcu_read_lock(CRYPTO_RCU_LOCK *lock) +{ + struct rcu_thr_data *data; + int i, available_qp = -1; + CRYPTO_THREAD_LOCAL *lkey = ossl_lib_ctx_get_rcukey(lock->ctx); + + /* + * we're going to access current_qp here so ask the + * processor to fetch it + */ + data = CRYPTO_THREAD_get_local(lkey); + + if (data == NULL) { + data = OPENSSL_zalloc(sizeof(*data)); + OPENSSL_assert(data != NULL); + CRYPTO_THREAD_set_local(lkey, data); + ossl_init_thread_start(NULL, lock->ctx, ossl_rcu_free_local_data); + } + + for (i = 0; i < MAX_QPS; i++) { + if (data->thread_qps[i].qp == NULL && available_qp == -1) + available_qp = i; + /* If we have a hold on this lock already, we're good */ + if (data->thread_qps[i].lock == lock) { + data->thread_qps[i].depth++; + return; + } + } + + /* + * if we get here, then we don't have a hold on this lock yet + */ + assert(available_qp != -1); + + data->thread_qps[available_qp].qp = get_hold_current_qp(lock); + data->thread_qps[available_qp].depth = 1; + data->thread_qps[available_qp].lock = lock; +} + +void ossl_rcu_read_unlock(CRYPTO_RCU_LOCK *lock) +{ + int i; + CRYPTO_THREAD_LOCAL *lkey = ossl_lib_ctx_get_rcukey(lock->ctx); + struct rcu_thr_data *data = CRYPTO_THREAD_get_local(lkey); + uint64_t ret; + + assert(data != NULL); + + for (i = 0; i < MAX_QPS; i++) { + if (data->thread_qps[i].lock == lock) { + /* + * we have to use __ATOMIC_RELEASE here + * to ensure that all preceding read instructions complete + * before the decrement is visible to ossl_synchronize_rcu + */ + data->thread_qps[i].depth--; + if (data->thread_qps[i].depth == 0) { + ret = ATOMIC_SUB_FETCH(&data->thread_qps[i].qp->users, + (uint64_t)1, __ATOMIC_RELEASE); + OPENSSL_assert(ret != UINT64_MAX); + data->thread_qps[i].qp = NULL; + data->thread_qps[i].lock = NULL; + } + return; + } + } + /* + * If we get here, we're trying to unlock a lock that we never acquired - + * that's fatal. + */ + assert(0); +} + +/* + * Write side allocation routine to get the current qp + * and replace it with a new one + */ +static struct rcu_qp *update_qp(CRYPTO_RCU_LOCK *lock, uint32_t *curr_id) +{ + uint32_t current_idx; + + pthread_mutex_lock(&lock->alloc_lock); + + /* + * we need at least one qp to be available with one + * left over, so that readers can start working on + * one that isn't yet being waited on + */ + while (lock->group_count - lock->writers_alloced < 2) + /* we have to wait for one to be free */ + pthread_cond_wait(&lock->alloc_signal, &lock->alloc_lock); + + current_idx = lock->current_alloc_idx; + + /* Allocate the qp */ + lock->writers_alloced++; + + /* increment the allocation index */ + lock->current_alloc_idx = + (lock->current_alloc_idx + 1) % lock->group_count; + + *curr_id = lock->id_ctr; + lock->id_ctr++; + + ATOMIC_STORE_N(uint32_t, &lock->reader_idx, lock->current_alloc_idx, + __ATOMIC_RELAXED); + + /* + * this should make sure that the new value of reader_idx is visible in + * get_hold_current_qp, directly after incrementing the users count + */ + ATOMIC_ADD_FETCH(&lock->qp_group[current_idx].users, (uint64_t)0, + __ATOMIC_RELEASE); + + /* wake up any waiters */ + pthread_cond_signal(&lock->alloc_signal); + pthread_mutex_unlock(&lock->alloc_lock); + return &lock->qp_group[current_idx]; +} + +static void retire_qp(CRYPTO_RCU_LOCK *lock, struct rcu_qp *qp) +{ + pthread_mutex_lock(&lock->alloc_lock); + lock->writers_alloced--; + pthread_cond_signal(&lock->alloc_signal); + pthread_mutex_unlock(&lock->alloc_lock); +} + +static struct rcu_qp *allocate_new_qp_group(CRYPTO_RCU_LOCK *lock, + uint32_t count) +{ + struct rcu_qp *new = + OPENSSL_zalloc(sizeof(*new) * count); + + lock->group_count = count; + return new; +} + +void ossl_rcu_write_lock(CRYPTO_RCU_LOCK *lock) +{ + pthread_mutex_lock(&lock->write_lock); + TSAN_FAKE_UNLOCK(&lock->write_lock); +} + +void ossl_rcu_write_unlock(CRYPTO_RCU_LOCK *lock) +{ + TSAN_FAKE_LOCK(&lock->write_lock); + pthread_mutex_unlock(&lock->write_lock); +} + +void ossl_synchronize_rcu(CRYPTO_RCU_LOCK *lock) +{ + struct rcu_qp *qp; + uint64_t count; + uint32_t curr_id; + struct rcu_cb_item *cb_items, *tmpcb; + + pthread_mutex_lock(&lock->write_lock); + cb_items = lock->cb_items; + lock->cb_items = NULL; + pthread_mutex_unlock(&lock->write_lock); + + qp = update_qp(lock, &curr_id); + + /* retire in order */ + pthread_mutex_lock(&lock->prior_lock); + while (lock->next_to_retire != curr_id) + pthread_cond_wait(&lock->prior_signal, &lock->prior_lock); + + /* + * wait for the reader count to reach zero + * Note the use of __ATOMIC_ACQUIRE here to ensure that any + * prior __ATOMIC_RELEASE write operation in ossl_rcu_read_unlock + * is visible prior to our read + * however this is likely just necessary to silence a tsan warning + * because the read side should not do any write operation + * outside the atomic itself + */ + do { + count = ATOMIC_LOAD_N(uint64_t, &qp->users, __ATOMIC_ACQUIRE); + } while (count != (uint64_t)0); + + lock->next_to_retire++; + pthread_cond_broadcast(&lock->prior_signal); + pthread_mutex_unlock(&lock->prior_lock); + + retire_qp(lock, qp); + + /* handle any callbacks that we have */ + while (cb_items != NULL) { + tmpcb = cb_items; + cb_items = cb_items->next; + tmpcb->fn(tmpcb->data); + OPENSSL_free(tmpcb); + } +} + +/* + * Note: This call assumes its made under the protection of + * ossl_rcu_write_lock + */ +int ossl_rcu_call(CRYPTO_RCU_LOCK *lock, rcu_cb_fn cb, void *data) +{ + struct rcu_cb_item *new = + OPENSSL_zalloc(sizeof(*new)); + + if (new == NULL) + return 0; + + new->data = data; + new->fn = cb; + + new->next = lock->cb_items; + lock->cb_items = new; + + return 1; +} + +void *ossl_rcu_uptr_deref(void **p) +{ + return ATOMIC_LOAD_N(pvoid, p, __ATOMIC_ACQUIRE); +} + +void ossl_rcu_assign_uptr(void **p, void **v) +{ + ATOMIC_STORE(pvoid, p, v, __ATOMIC_RELEASE); +} + +CRYPTO_RCU_LOCK *ossl_rcu_lock_new(int num_writers, OSSL_LIB_CTX *ctx) +{ + struct rcu_lock_st *new; + + /* + * We need a minimum of 2 qp's + */ + if (num_writers < 2) + num_writers = 2; + + ctx = ossl_lib_ctx_get_concrete(ctx); + if (ctx == NULL) + return 0; + + new = OPENSSL_zalloc(sizeof(*new)); + if (new == NULL) + return NULL; + + new->ctx = ctx; + pthread_mutex_init(&new->write_lock, NULL); + pthread_mutex_init(&new->prior_lock, NULL); + pthread_mutex_init(&new->alloc_lock, NULL); + pthread_cond_init(&new->prior_signal, NULL); + pthread_cond_init(&new->alloc_signal, NULL); + + new->qp_group = allocate_new_qp_group(new, num_writers); + if (new->qp_group == NULL) { + OPENSSL_free(new); + new = NULL; + } + + return new; +} + +void ossl_rcu_lock_free(CRYPTO_RCU_LOCK *lock) +{ + struct rcu_lock_st *rlock = (struct rcu_lock_st *)lock; + + if (lock == NULL) + return; + + /* make sure we're synchronized */ + ossl_synchronize_rcu(rlock); + + OPENSSL_free(rlock->qp_group); + /* There should only be a single qp left now */ + OPENSSL_free(rlock); +} + CRYPTO_RWLOCK *CRYPTO_THREAD_lock_new(void) { # ifdef USE_RWLOCK CRYPTO_RWLOCK *lock; - if ((lock = OPENSSL_zalloc(sizeof(pthread_rwlock_t))) == NULL) { + if ((lock = OPENSSL_zalloc(sizeof(pthread_rwlock_t))) == NULL) /* Don't set error, to avoid recursion blowup. */ return NULL; - } if (pthread_rwlock_init(lock, NULL) != 0) { OPENSSL_free(lock); @@ -60,10 +593,9 @@ CRYPTO_RWLOCK *CRYPTO_THREAD_lock_new(void) pthread_mutexattr_t attr; CRYPTO_RWLOCK *lock; - if ((lock = OPENSSL_zalloc(sizeof(pthread_mutex_t))) == NULL) { + if ((lock = OPENSSL_zalloc(sizeof(pthread_mutex_t))) == NULL) /* Don't set error, to avoid recursion blowup. */ return NULL; - } /* * We don't use recursive mutexes, but try to catch errors if we do. @@ -222,6 +754,58 @@ int CRYPTO_atomic_add(int *val, int amount, int *ret, CRYPTO_RWLOCK *lock) return 1; } +int CRYPTO_atomic_add64(uint64_t *val, uint64_t op, uint64_t *ret, + CRYPTO_RWLOCK *lock) +{ +# if defined(__GNUC__) && defined(__ATOMIC_ACQ_REL) && !defined(BROKEN_CLANG_ATOMICS) + if (__atomic_is_lock_free(sizeof(*val), val)) { + *ret = __atomic_add_fetch(val, op, __ATOMIC_ACQ_REL); + return 1; + } +# elif defined(__sun) && (defined(__SunOS_5_10) || defined(__SunOS_5_11)) + /* This will work for all future Solaris versions. */ + if (ret != NULL) { + *ret = atomic_add_64_nv(val, op); + return 1; + } +# endif + if (lock == NULL || !CRYPTO_THREAD_write_lock(lock)) + return 0; + *val += op; + *ret = *val; + + if (!CRYPTO_THREAD_unlock(lock)) + return 0; + + return 1; +} + +int CRYPTO_atomic_and(uint64_t *val, uint64_t op, uint64_t *ret, + CRYPTO_RWLOCK *lock) +{ +# if defined(__GNUC__) && defined(__ATOMIC_ACQ_REL) && !defined(BROKEN_CLANG_ATOMICS) + if (__atomic_is_lock_free(sizeof(*val), val)) { + *ret = __atomic_and_fetch(val, op, __ATOMIC_ACQ_REL); + return 1; + } +# elif defined(__sun) && (defined(__SunOS_5_10) || defined(__SunOS_5_11)) + /* This will work for all future Solaris versions. */ + if (ret != NULL) { + *ret = atomic_and_64_nv(val, op); + return 1; + } +# endif + if (lock == NULL || !CRYPTO_THREAD_write_lock(lock)) + return 0; + *val &= op; + *ret = *val; + + if (!CRYPTO_THREAD_unlock(lock)) + return 0; + + return 1; +} + int CRYPTO_atomic_or(uint64_t *val, uint64_t op, uint64_t *ret, CRYPTO_RWLOCK *lock) { @@ -250,7 +834,7 @@ int CRYPTO_atomic_or(uint64_t *val, uint64_t op, uint64_t *ret, int CRYPTO_atomic_load(uint64_t *val, uint64_t *ret, CRYPTO_RWLOCK *lock) { -# if defined(__GNUC__) && defined(__ATOMIC_ACQUIRE) && !defined(BROKEN_CLANG_ATOMICS) +# if defined(__GNUC__) && defined(__ATOMIC_ACQ_REL) && !defined(BROKEN_CLANG_ATOMICS) if (__atomic_is_lock_free(sizeof(*val), val)) { __atomic_load(val, ret, __ATOMIC_ACQUIRE); return 1; @@ -270,6 +854,53 @@ int CRYPTO_atomic_load(uint64_t *val, uint64_t *ret, CRYPTO_RWLOCK *lock) return 1; } + +int CRYPTO_atomic_store(uint64_t *dst, uint64_t val, CRYPTO_RWLOCK *lock) +{ +# if defined(__GNUC__) && defined(__ATOMIC_ACQ_REL) && !defined(BROKEN_CLANG_ATOMICS) + if (__atomic_is_lock_free(sizeof(*dst), dst)) { + __atomic_store(dst, &val, __ATOMIC_RELEASE); + return 1; + } +# elif defined(__sun) && (defined(__SunOS_5_10) || defined(__SunOS_5_11)) + /* This will work for all future Solaris versions. */ + if (dst != NULL) { + atomic_swap_64(dst, val); + return 1; + } +# endif + if (lock == NULL || !CRYPTO_THREAD_write_lock(lock)) + return 0; + *dst = val; + if (!CRYPTO_THREAD_unlock(lock)) + return 0; + + return 1; +} + +int CRYPTO_atomic_load_int(int *val, int *ret, CRYPTO_RWLOCK *lock) +{ +# if defined(__GNUC__) && defined(__ATOMIC_ACQ_REL) && !defined(BROKEN_CLANG_ATOMICS) + if (__atomic_is_lock_free(sizeof(*val), val)) { + __atomic_load(val, ret, __ATOMIC_ACQUIRE); + return 1; + } +# elif defined(__sun) && (defined(__SunOS_5_10) || defined(__SunOS_5_11)) + /* This will work for all future Solaris versions. */ + if (ret != NULL) { + *ret = (int)atomic_or_uint_nv((unsigned int *)val, 0); + return 1; + } +# endif + if (lock == NULL || !CRYPTO_THREAD_read_lock(lock)) + return 0; + *ret = *val; + if (!CRYPTO_THREAD_unlock(lock)) + return 0; + + return 1; +} + # ifndef FIPS_MODULE int openssl_init_fork_handlers(void) { |