| /* |
| * |
| * Copyright 2016 gRPC authors. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| * |
| */ |
| |
| #include <grpc/support/port_platform.h> |
| |
| #include "src/core/lib/slice/slice_internal.h" |
| #include "src/core/lib/slice/slice_utils.h" |
| |
| #include <inttypes.h> |
| #include <string.h> |
| |
| #include <grpc/support/alloc.h> |
| #include <grpc/support/log.h> |
| |
| #include "src/core/lib/gpr/murmur_hash.h" |
| #include "src/core/lib/gprpp/sync.h" |
| #include "src/core/lib/iomgr/iomgr_internal.h" /* for iomgr_abort_on_leaks() */ |
| #include "src/core/lib/profiling/timers.h" |
| #include "src/core/lib/slice/slice_string_helpers.h" |
| #include "src/core/lib/transport/static_metadata.h" |
| |
| #define LOG2_SHARD_COUNT 5 |
| #define SHARD_COUNT (1 << LOG2_SHARD_COUNT) |
| #define INITIAL_SHARD_CAPACITY 8 |
| |
| #define TABLE_IDX(hash, capacity) (((hash) >> LOG2_SHARD_COUNT) % (capacity)) |
| #define SHARD_IDX(hash) ((hash) & ((1 << LOG2_SHARD_COUNT) - 1)) |
| |
| using grpc_core::InternedSliceRefcount; |
| |
| typedef struct slice_shard { |
| grpc_core::Mutex mu; |
| InternedSliceRefcount** strs; |
| size_t count; |
| size_t capacity; |
| } slice_shard; |
| |
| static slice_shard* g_shards; |
| |
| struct static_metadata_hash_ent { |
| uint32_t hash; |
| uint32_t idx; |
| }; |
| static static_metadata_hash_ent |
| static_metadata_hash[4 * GRPC_STATIC_MDSTR_COUNT]; |
| static uint32_t max_static_metadata_hash_probe; |
| uint32_t grpc_static_metadata_hash_values[GRPC_STATIC_MDSTR_COUNT]; |
| |
| namespace grpc_core { |
| |
| /* hash seed: decided at initialization time */ |
| uint32_t g_hash_seed; |
| static bool g_forced_hash_seed = false; |
| |
| InternedSliceRefcount::~InternedSliceRefcount() { |
| slice_shard* shard = &g_shards[SHARD_IDX(this->hash)]; |
| MutexLock lock(&shard->mu); |
| InternedSliceRefcount** prev_next; |
| InternedSliceRefcount* cur; |
| for (prev_next = &shard->strs[TABLE_IDX(this->hash, shard->capacity)], |
| cur = *prev_next; |
| cur != this; prev_next = &cur->bucket_next, cur = cur->bucket_next) { |
| } |
| *prev_next = cur->bucket_next; |
| shard->count--; |
| } |
| |
| } // namespace grpc_core |
| |
| static void grow_shard(slice_shard* shard) { |
| GPR_TIMER_SCOPE("grow_strtab", 0); |
| |
| size_t capacity = shard->capacity * 2; |
| size_t i; |
| InternedSliceRefcount** strtab; |
| InternedSliceRefcount *s, *next; |
| |
| strtab = static_cast<InternedSliceRefcount**>( |
| gpr_zalloc(sizeof(InternedSliceRefcount*) * capacity)); |
| |
| for (i = 0; i < shard->capacity; i++) { |
| for (s = shard->strs[i]; s; s = next) { |
| size_t idx = TABLE_IDX(s->hash, capacity); |
| next = s->bucket_next; |
| s->bucket_next = strtab[idx]; |
| strtab[idx] = s; |
| } |
| } |
| gpr_free(shard->strs); |
| shard->strs = strtab; |
| shard->capacity = capacity; |
| } |
| |
| grpc_core::InternedSlice::InternedSlice(InternedSliceRefcount* s) { |
| refcount = &s->base; |
| data.refcounted.bytes = reinterpret_cast<uint8_t*>(s + 1); |
| data.refcounted.length = s->length; |
| } |
| |
| uint32_t grpc_slice_default_hash_impl(grpc_slice s) { |
| return gpr_murmur_hash3(GRPC_SLICE_START_PTR(s), GRPC_SLICE_LENGTH(s), |
| grpc_core::g_hash_seed); |
| } |
| |
| uint32_t grpc_static_slice_hash(grpc_slice s) { |
| return grpc_static_metadata_hash_values[GRPC_STATIC_METADATA_INDEX(s)]; |
| } |
| |
| int grpc_static_slice_eq(grpc_slice a, grpc_slice b) { |
| return GRPC_STATIC_METADATA_INDEX(a) == GRPC_STATIC_METADATA_INDEX(b); |
| } |
| |
| uint32_t grpc_slice_hash(grpc_slice s) { return grpc_slice_hash_internal(s); } |
| |
| grpc_slice grpc_slice_maybe_static_intern(grpc_slice slice, |
| bool* returned_slice_is_different) { |
| if (GRPC_IS_STATIC_METADATA_STRING(slice)) { |
| return slice; |
| } |
| |
| uint32_t hash = grpc_slice_hash_internal(slice); |
| for (uint32_t i = 0; i <= max_static_metadata_hash_probe; i++) { |
| static_metadata_hash_ent ent = |
| static_metadata_hash[(hash + i) % GPR_ARRAY_SIZE(static_metadata_hash)]; |
| const grpc_core::StaticMetadataSlice* static_slice_table = |
| grpc_static_slice_table(); |
| if (ent.hash == hash && ent.idx < GRPC_STATIC_MDSTR_COUNT && |
| grpc_slice_eq_static_interned(slice, static_slice_table[ent.idx])) { |
| *returned_slice_is_different = true; |
| return static_slice_table[ent.idx]; |
| } |
| } |
| |
| return slice; |
| } |
| |
| grpc_slice grpc_slice_intern(grpc_slice slice) { |
| /* TODO(arjunroy): At present, this is capable of returning either a static or |
| an interned slice. This yields weirdness like the constructor for |
| ManagedMemorySlice instantiating itself as an instance of a derived type |
| (StaticMetadataSlice or InternedSlice). Should reexamine. */ |
| return grpc_core::ManagedMemorySlice(&slice); |
| } |
| |
| // Attempt to see if the provided slice or string matches a static slice. |
| // SliceArgs is either a const grpc_slice& or const pair<const char*, size_t>&. |
| // In either case, hash is the pre-computed hash value. |
| // |
| // Returns: a matching static slice, or null. |
| template <typename SliceArgs> |
| static const grpc_core::StaticMetadataSlice* MatchStaticSlice( |
| uint32_t hash, const SliceArgs& args) { |
| for (uint32_t i = 0; i <= max_static_metadata_hash_probe; i++) { |
| static_metadata_hash_ent ent = |
| static_metadata_hash[(hash + i) % GPR_ARRAY_SIZE(static_metadata_hash)]; |
| const grpc_core::StaticMetadataSlice* static_slice_table = |
| grpc_static_slice_table(); |
| if (ent.hash == hash && ent.idx < GRPC_STATIC_MDSTR_COUNT && |
| static_slice_table[ent.idx] == args) { |
| return &static_slice_table[ent.idx]; |
| } |
| } |
| return nullptr; |
| } |
| |
| // Helper methods to enable us to select appropriately overloaded slice methods |
| // whether we're dealing with a slice, or a buffer with length, when interning |
| // strings. Helpers for FindOrCreateInternedSlice(). |
| static const char* GetBuffer(const std::pair<const char*, size_t>& buflen) { |
| return buflen.first; |
| } |
| static size_t GetLength(const std::pair<const char*, size_t>& buflen) { |
| return buflen.second; |
| } |
| static const void* GetBuffer(const grpc_slice& slice) { |
| return GRPC_SLICE_START_PTR(slice); |
| } |
| static size_t GetLength(const grpc_slice& slice) { |
| return GRPC_SLICE_LENGTH(slice); |
| } |
| |
| // Creates an interned slice for a string that does not currently exist in the |
| // intern table. SliceArgs is either a const grpc_slice& or a const |
| // pair<const char*, size_t>&. Hash is the pre-computed hash value. We must |
| // already hold the shard lock. Helper for FindOrCreateInternedSlice(). |
| // |
| // Returns: a newly interned slice. |
| template <typename SliceArgs> |
| static InternedSliceRefcount* InternNewStringLocked(slice_shard* shard, |
| size_t shard_idx, |
| uint32_t hash, |
| const SliceArgs& args) { |
| /* string data goes after the internal_string header */ |
| size_t len = GetLength(args); |
| const void* buffer = GetBuffer(args); |
| InternedSliceRefcount* s = |
| static_cast<InternedSliceRefcount*>(gpr_malloc(sizeof(*s) + len)); |
| new (s) grpc_core::InternedSliceRefcount(len, hash, shard->strs[shard_idx]); |
| // TODO(arjunroy): Investigate why hpack tried to intern the nullptr string. |
| // https://github.com/grpc/grpc/pull/20110#issuecomment-526729282 |
| if (len > 0) { |
| memcpy(reinterpret_cast<char*>(s + 1), buffer, len); |
| } |
| shard->strs[shard_idx] = s; |
| shard->count++; |
| if (shard->count > shard->capacity * 2) { |
| grow_shard(shard); |
| } |
| return s; |
| } |
| |
| // Attempt to see if the provided slice or string matches an existing interned |
| // slice. SliceArgs... is either a const grpc_slice& or a string and length. In |
| // either case, hash is the pre-computed hash value. We must already hold the |
| // shard lock. Helper for FindOrCreateInternedSlice(). |
| // |
| // Returns: a pre-existing matching static slice, or null. |
| template <typename SliceArgs> |
| static InternedSliceRefcount* MatchInternedSliceLocked(uint32_t hash, |
| size_t idx, |
| const SliceArgs& args) { |
| InternedSliceRefcount* s; |
| slice_shard* shard = &g_shards[SHARD_IDX(hash)]; |
| /* search for an existing string */ |
| for (s = shard->strs[idx]; s; s = s->bucket_next) { |
| if (s->hash == hash && grpc_core::InternedSlice(s) == args) { |
| if (s->refcnt.RefIfNonZero()) { |
| return s; |
| } |
| } |
| } |
| return nullptr; |
| } |
| |
| // Attempt to see if the provided slice or string matches an existing interned |
| // slice, and failing that, create an interned slice with its contents. Returns |
| // either the existing matching interned slice or the newly created one. |
| // SliceArgs is either a const grpc_slice& or const pair<const char*, size_t>&. |
| // In either case, hash is the pre-computed hash value. We do not hold the |
| // shard lock here, but do take it. |
| // |
| // Returns: an interned slice, either pre-existing/matched or newly created. |
| template <typename SliceArgs> |
| static InternedSliceRefcount* FindOrCreateInternedSlice(uint32_t hash, |
| const SliceArgs& args) { |
| slice_shard* shard = &g_shards[SHARD_IDX(hash)]; |
| grpc_core::MutexLock lock(&shard->mu); |
| const size_t idx = TABLE_IDX(hash, shard->capacity); |
| InternedSliceRefcount* s = MatchInternedSliceLocked(hash, idx, args); |
| if (s == nullptr) { |
| s = InternNewStringLocked(shard, idx, hash, args); |
| } |
| return s; |
| } |
| |
| grpc_core::ManagedMemorySlice::ManagedMemorySlice(const char* string) |
| : grpc_core::ManagedMemorySlice::ManagedMemorySlice(string, |
| strlen(string)) {} |
| |
| grpc_core::ManagedMemorySlice::ManagedMemorySlice(const char* buf, size_t len) { |
| GPR_TIMER_SCOPE("grpc_slice_intern", 0); |
| const uint32_t hash = gpr_murmur_hash3(buf, len, g_hash_seed); |
| const StaticMetadataSlice* static_slice = |
| MatchStaticSlice(hash, std::pair<const char*, size_t>(buf, len)); |
| if (static_slice) { |
| *this = *static_slice; |
| } else { |
| *this = grpc_core::InternedSlice(FindOrCreateInternedSlice( |
| hash, std::pair<const char*, size_t>(buf, len))); |
| } |
| } |
| |
| grpc_core::ManagedMemorySlice::ManagedMemorySlice(const grpc_slice* slice_ptr) { |
| GPR_TIMER_SCOPE("grpc_slice_intern", 0); |
| const grpc_slice& slice = *slice_ptr; |
| if (GRPC_IS_STATIC_METADATA_STRING(slice)) { |
| *this = static_cast<const grpc_core::StaticMetadataSlice&>(slice); |
| return; |
| } |
| const uint32_t hash = grpc_slice_hash_internal(slice); |
| const StaticMetadataSlice* static_slice = MatchStaticSlice(hash, slice); |
| if (static_slice) { |
| *this = *static_slice; |
| } else { |
| *this = grpc_core::InternedSlice(FindOrCreateInternedSlice(hash, slice)); |
| } |
| } |
| |
| void grpc_test_only_set_slice_hash_seed(uint32_t seed) { |
| grpc_core::g_hash_seed = seed; |
| grpc_core::g_forced_hash_seed = true; |
| } |
| |
| void grpc_slice_intern_init(void) { |
| if (!grpc_core::g_forced_hash_seed) { |
| grpc_core::g_hash_seed = |
| static_cast<uint32_t>(gpr_now(GPR_CLOCK_REALTIME).tv_nsec); |
| } |
| g_shards = new slice_shard[SHARD_COUNT]; |
| for (size_t i = 0; i < SHARD_COUNT; i++) { |
| slice_shard* shard = &g_shards[i]; |
| shard->count = 0; |
| shard->capacity = INITIAL_SHARD_CAPACITY; |
| shard->strs = static_cast<InternedSliceRefcount**>( |
| gpr_zalloc(sizeof(*shard->strs) * shard->capacity)); |
| } |
| for (size_t i = 0; i < GPR_ARRAY_SIZE(static_metadata_hash); i++) { |
| static_metadata_hash[i].hash = 0; |
| static_metadata_hash[i].idx = GRPC_STATIC_MDSTR_COUNT; |
| } |
| max_static_metadata_hash_probe = 0; |
| const grpc_core::StaticMetadataSlice* static_slice_table = |
| grpc_static_slice_table(); |
| for (size_t i = 0; i < GRPC_STATIC_MDSTR_COUNT; i++) { |
| grpc_static_metadata_hash_values[i] = |
| grpc_slice_default_hash_internal(static_slice_table[i]); |
| for (size_t j = 0; j < GPR_ARRAY_SIZE(static_metadata_hash); j++) { |
| size_t slot = (grpc_static_metadata_hash_values[i] + j) % |
| GPR_ARRAY_SIZE(static_metadata_hash); |
| if (static_metadata_hash[slot].idx == GRPC_STATIC_MDSTR_COUNT) { |
| static_metadata_hash[slot].hash = grpc_static_metadata_hash_values[i]; |
| static_metadata_hash[slot].idx = static_cast<uint32_t>(i); |
| if (j > max_static_metadata_hash_probe) { |
| max_static_metadata_hash_probe = static_cast<uint32_t>(j); |
| } |
| break; |
| } |
| } |
| } |
| // Handle KV hash for all static mdelems. |
| for (size_t i = 0; i < GRPC_STATIC_MDELEM_COUNT; ++i) { |
| grpc_static_mdelem_table()[i].HashInit(); |
| } |
| } |
| |
| void grpc_slice_intern_shutdown(void) { |
| for (size_t i = 0; i < SHARD_COUNT; i++) { |
| slice_shard* shard = &g_shards[i]; |
| /* TODO(ctiller): GPR_ASSERT(shard->count == 0); */ |
| if (shard->count != 0) { |
| gpr_log(GPR_DEBUG, "WARNING: %" PRIuPTR " metadata strings were leaked", |
| shard->count); |
| for (size_t j = 0; j < shard->capacity; j++) { |
| for (InternedSliceRefcount* s = shard->strs[j]; s; s = s->bucket_next) { |
| char* text = grpc_dump_slice(grpc_core::InternedSlice(s), |
| GPR_DUMP_HEX | GPR_DUMP_ASCII); |
| gpr_log(GPR_DEBUG, "LEAKED: %s", text); |
| gpr_free(text); |
| } |
| } |
| if (grpc_iomgr_abort_on_leaks()) { |
| abort(); |
| } |
| } |
| gpr_free(shard->strs); |
| } |
| delete[] g_shards; |
| } |