X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=src%2Fshared%2Fhashmap.c;h=ebc2ef19bba8556e81cded8a5d0ba961f68338f0;hb=e4c691b59db60ef2e6d8e64766d6ae02cd0dd457;hp=633079277d758f7961a2c854d84c0e861d6ffafa;hpb=45fa9e29f8c9759c8f2f4238fed956f695c73dc3;p=elogind.git diff --git a/src/shared/hashmap.c b/src/shared/hashmap.c index 633079277..ebc2ef19b 100644 --- a/src/shared/hashmap.c +++ b/src/shared/hashmap.c @@ -27,6 +27,8 @@ #include "util.h" #include "hashmap.h" #include "macro.h" +#include "siphash24.h" +#include "mempool.h" #define INITIAL_N_BUCKETS 31 @@ -38,176 +40,164 @@ struct hashmap_entry { }; struct Hashmap { - hash_func_t hash_func; - compare_func_t compare_func; + const struct hash_ops *hash_ops; struct hashmap_entry *iterate_list_head, *iterate_list_tail; struct hashmap_entry ** buckets; unsigned n_buckets, n_entries; - bool from_pool; + uint8_t hash_key[HASH_KEY_SIZE]; + bool from_pool:1; }; -struct pool { - struct pool *next; - unsigned n_tiles; - unsigned n_used; +struct hashmap_tile { + Hashmap h; + struct hashmap_entry *initial_buckets[INITIAL_N_BUCKETS]; }; -static struct pool *first_hashmap_pool = NULL; -static void *first_hashmap_tile = NULL; - -static struct pool *first_entry_pool = NULL; -static void *first_entry_tile = NULL; - -static void* allocate_tile(struct pool **first_pool, void **first_tile, size_t tile_size) { - unsigned i; - - /* When a tile is released we add it to the list and simply - * place the next pointer at its offset 0. */ - - assert(tile_size >= sizeof(void*)); - - if (*first_tile) { - void *r; - - r = *first_tile; - *first_tile = * (void**) (*first_tile); - return r; - } - - if (_unlikely_(!*first_pool) || _unlikely_((*first_pool)->n_used >= (*first_pool)->n_tiles)) { - unsigned n; - size_t size; - struct pool *p; - - n = *first_pool ? (*first_pool)->n_tiles : 0; - n = MAX(512U, n * 2); - size = PAGE_ALIGN(ALIGN(sizeof(struct pool)) + n*tile_size); - n = (size - ALIGN(sizeof(struct pool))) / tile_size; - - p = malloc(size); - if (!p) - return NULL; - - p->next = *first_pool; - p->n_tiles = n; - p->n_used = 0; - - *first_pool = p; - } - - i = (*first_pool)->n_used++; - - return ((uint8_t*) (*first_pool)) + ALIGN(sizeof(struct pool)) + i*tile_size; -} - -static void deallocate_tile(void **first_tile, void *p) { - * (void**) p = *first_tile; - *first_tile = p; -} +static DEFINE_MEMPOOL(hashmap_pool, struct hashmap_tile, 8); +static DEFINE_MEMPOOL(hashmap_entry_pool, struct hashmap_entry, 64); #ifdef VALGRIND -static void drop_pool(struct pool *p) { - while (p) { - struct pool *n; - n = p->next; - free(p); - p = n; - } -} - -__attribute__((destructor)) static void cleanup_pool(void) { +__attribute__((destructor)) static void cleanup_pools(void) { /* Be nice to valgrind */ - drop_pool(first_hashmap_pool); - drop_pool(first_entry_pool); + mempool_drop(&hashmap_entry_pool); + mempool_drop(&hashmap_pool); } #endif -unsigned string_hash_func(const void *p) { - unsigned hash = 5381; - const signed char *c; - - /* DJB's hash function */ - - for (c = p; *c; c++) - hash = (hash << 5) + hash + (unsigned) *c; - - return hash; +unsigned long string_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) { + uint64_t u; + siphash24((uint8_t*) &u, p, strlen(p), hash_key); + return (unsigned long) u; } int string_compare_func(const void *a, const void *b) { return strcmp(a, b); } -unsigned trivial_hash_func(const void *p) { - return PTR_TO_UINT(p); +const struct hash_ops string_hash_ops = { + .hash = string_hash_func, + .compare = string_compare_func +}; + +unsigned long trivial_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) { + uint64_t u; + siphash24((uint8_t*) &u, &p, sizeof(p), hash_key); + return (unsigned long) u; } int trivial_compare_func(const void *a, const void *b) { return a < b ? -1 : (a > b ? 1 : 0); } -unsigned uint64_hash_func(const void *p) { - uint64_t u; - - assert_cc(sizeof(uint64_t) == 2*sizeof(unsigned)); - - u = *(const uint64_t*) p; +const struct hash_ops trivial_hash_ops = { + .hash = trivial_hash_func, + .compare = trivial_compare_func +}; - return (unsigned) ((u >> 32) ^ u); +unsigned long uint64_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) { + uint64_t u; + siphash24((uint8_t*) &u, p, sizeof(uint64_t), hash_key); + return (unsigned long) u; } int uint64_compare_func(const void *_a, const void *_b) { uint64_t a, b; - a = *(const uint64_t*) _a; b = *(const uint64_t*) _b; + return a < b ? -1 : (a > b ? 1 : 0); +} +const struct hash_ops uint64_hash_ops = { + .hash = uint64_hash_func, + .compare = uint64_compare_func +}; + +#if SIZEOF_DEV_T != 8 +unsigned long devt_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) { + uint64_t u; + siphash24((uint8_t*) &u, p, sizeof(dev_t), hash_key); + return (unsigned long) u; +} + +int devt_compare_func(const void *_a, const void *_b) { + dev_t a, b; + a = *(const dev_t*) _a; + b = *(const dev_t*) _b; return a < b ? -1 : (a > b ? 1 : 0); } -Hashmap *hashmap_new(hash_func_t hash_func, compare_func_t compare_func) { +const struct hash_ops devt_hash_ops = { + .hash = devt_hash_func, + .compare = devt_compare_func +}; +#endif + +static unsigned bucket_hash(Hashmap *h, const void *p) { + return (unsigned) (h->hash_ops->hash(p, h->hash_key) % h->n_buckets); +} + +static void get_hash_key(uint8_t hash_key[HASH_KEY_SIZE], bool reuse_is_ok) { + static uint8_t current[HASH_KEY_SIZE]; + static bool current_initialized = false; + + /* Returns a hash function key to use. In order to keep things + * fast we will not generate a new key each time we allocate a + * new hash table. Instead, we'll just reuse the most recently + * generated one, except if we never generated one or when we + * are rehashing an entire hash table because we reached a + * fill level */ + + if (!current_initialized || !reuse_is_ok) { + random_bytes(current, sizeof(current)); + current_initialized = true; + } + + memcpy(hash_key, current, sizeof(current)); +} + +Hashmap *hashmap_new(const struct hash_ops *hash_ops) { bool b; + struct hashmap_tile *ht; Hashmap *h; - size_t size; b = is_main_thread(); - size = ALIGN(sizeof(Hashmap)) + INITIAL_N_BUCKETS * sizeof(struct hashmap_entry*); - if (b) { - h = allocate_tile(&first_hashmap_pool, &first_hashmap_tile, size); - if (!h) + ht = mempool_alloc_tile(&hashmap_pool); + if (!ht) return NULL; - memset(h, 0, size); + memzero(ht, sizeof(struct hashmap_tile)); } else { - h = malloc0(size); + ht = malloc0(sizeof(struct hashmap_tile)); - if (!h) + if (!ht) return NULL; } - h->hash_func = hash_func ? hash_func : trivial_hash_func; - h->compare_func = compare_func ? compare_func : trivial_compare_func; + h = &ht->h; + h->hash_ops = hash_ops ? hash_ops : &trivial_hash_ops; h->n_buckets = INITIAL_N_BUCKETS; h->n_entries = 0; h->iterate_list_head = h->iterate_list_tail = NULL; - h->buckets = (struct hashmap_entry**) ((uint8_t*) h + ALIGN(sizeof(Hashmap))); + h->buckets = ht->initial_buckets; h->from_pool = b; + get_hash_key(h->hash_key, true); + return h; } -int hashmap_ensure_allocated(Hashmap **h, hash_func_t hash_func, compare_func_t compare_func) { +int hashmap_ensure_allocated(Hashmap **h, const struct hash_ops *hash_ops) { Hashmap *q; assert(h); @@ -215,7 +205,7 @@ int hashmap_ensure_allocated(Hashmap **h, hash_func_t hash_func, compare_func_t if (*h) return 0; - q = hashmap_new(hash_func, compare_func); + q = hashmap_new(hash_ops); if (!q) return -ENOMEM; @@ -284,12 +274,11 @@ static void remove_entry(Hashmap *h, struct hashmap_entry *e) { assert(h); assert(e); - hash = h->hash_func(e->key) % h->n_buckets; - + hash = bucket_hash(h, e->key); unlink_entry(h, e, hash); if (h->from_pool) - deallocate_tile(&first_entry_tile, e); + mempool_free_tile(&hashmap_entry_pool, e); else free(e); } @@ -307,7 +296,7 @@ void hashmap_free(Hashmap*h) { free(h->buckets); if (h->from_pool) - deallocate_tile(&first_hashmap_tile, h); + mempool_free_tile(&hashmap_pool, container_of(h, struct hashmap_tile, h)); else free(h); } @@ -368,40 +357,53 @@ void hashmap_clear_free_free(Hashmap *h) { } } - static struct hashmap_entry *hash_scan(Hashmap *h, unsigned hash, const void *key) { struct hashmap_entry *e; assert(h); assert(hash < h->n_buckets); for (e = h->buckets[hash]; e; e = e->bucket_next) - if (h->compare_func(e->key, key) == 0) + if (h->hash_ops->compare(e->key, key) == 0) return e; return NULL; } -static bool resize_buckets(Hashmap *h) { - unsigned m; +static int resize_buckets(Hashmap *h, unsigned entries_add) { struct hashmap_entry **n, *i; + unsigned m, new_n_entries, new_n_buckets; + uint8_t nkey[HASH_KEY_SIZE]; assert(h); - if (_likely_(h->n_entries*4 < h->n_buckets*3)) - return false; + new_n_entries = h->n_entries + entries_add; + + /* overflow? */ + if (_unlikely_(new_n_entries < entries_add || new_n_entries > UINT_MAX / 4)) + return -ENOMEM; + + new_n_buckets = new_n_entries * 4 / 3; + + if (_likely_(new_n_buckets <= h->n_buckets)) + return 0; - /* Increase by four */ - m = (h->n_entries+1)*4-1; + /* Increase by four at least */ + m = MAX((h->n_entries+1)*4-1, new_n_buckets); /* If we hit OOM we simply risk packed hashmaps... */ n = new0(struct hashmap_entry*, m); if (!n) - return false; + return -ENOMEM; + + /* Let's use a different randomized hash key for the + * extension, so that people cannot guess what we are using + * here forever */ + get_hash_key(nkey, false); for (i = h->iterate_list_head; i; i = i->iterate_next) { - unsigned hash, x; + unsigned long old_bucket, new_bucket; - hash = h->hash_func(i->key); + old_bucket = h->hash_ops->hash(i->key, h->hash_key) % h->n_buckets; /* First, drop from old bucket table */ if (i->bucket_next) @@ -410,16 +412,16 @@ static bool resize_buckets(Hashmap *h) { if (i->bucket_previous) i->bucket_previous->bucket_next = i->bucket_next; else - h->buckets[hash % h->n_buckets] = i->bucket_next; + h->buckets[old_bucket] = i->bucket_next; /* Then, add to new backet table */ - x = hash % m; + new_bucket = h->hash_ops->hash(i->key, nkey) % m; - i->bucket_next = n[x]; + i->bucket_next = n[new_bucket]; i->bucket_previous = NULL; - if (n[x]) - n[x]->bucket_previous = i; - n[x] = i; + if (n[new_bucket]) + n[new_bucket]->bucket_previous = i; + n[new_bucket] = i; } if (h->buckets != (struct hashmap_entry**) ((uint8_t*) h + ALIGN(sizeof(Hashmap)))) @@ -428,28 +430,21 @@ static bool resize_buckets(Hashmap *h) { h->buckets = n; h->n_buckets = m; - return true; -} + memcpy(h->hash_key, nkey, HASH_KEY_SIZE); -int hashmap_put(Hashmap *h, const void *key, void *value) { - struct hashmap_entry *e; - unsigned hash; + return 1; +} - assert(h); +static int __hashmap_put(Hashmap *h, const void *key, void *value, unsigned hash) { + /* For when we know no such entry exists yet */ - hash = h->hash_func(key) % h->n_buckets; - e = hash_scan(h, hash, key); - if (e) { - if (e->value == value) - return 0; - return -EEXIST; - } + struct hashmap_entry *e; - if (resize_buckets(h)) - hash = h->hash_func(key) % h->n_buckets; + if (resize_buckets(h, 1) > 0) + hash = bucket_hash(h, key); if (h->from_pool) - e = allocate_tile(&first_entry_pool, &first_entry_tile, sizeof(struct hashmap_entry)); + e = mempool_alloc_tile(&hashmap_entry_pool); else e = new(struct hashmap_entry, 1); @@ -464,13 +459,30 @@ int hashmap_put(Hashmap *h, const void *key, void *value) { return 1; } +int hashmap_put(Hashmap *h, const void *key, void *value) { + struct hashmap_entry *e; + unsigned hash; + + assert(h); + + hash = bucket_hash(h, key); + e = hash_scan(h, hash, key); + if (e) { + if (e->value == value) + return 0; + return -EEXIST; + } + + return __hashmap_put(h, key, value, hash); +} + int hashmap_replace(Hashmap *h, const void *key, void *value) { struct hashmap_entry *e; unsigned hash; assert(h); - hash = h->hash_func(key) % h->n_buckets; + hash = bucket_hash(h, key); e = hash_scan(h, hash, key); if (e) { e->key = key; @@ -478,7 +490,7 @@ int hashmap_replace(Hashmap *h, const void *key, void *value) { return 0; } - return hashmap_put(h, key, value); + return __hashmap_put(h, key, value, hash); } int hashmap_update(Hashmap *h, const void *key, void *value) { @@ -487,7 +499,7 @@ int hashmap_update(Hashmap *h, const void *key, void *value) { assert(h); - hash = h->hash_func(key) % h->n_buckets; + hash = bucket_hash(h, key); e = hash_scan(h, hash, key); if (!e) return -ENOENT; @@ -503,7 +515,7 @@ void* hashmap_get(Hashmap *h, const void *key) { if (!h) return NULL; - hash = h->hash_func(key) % h->n_buckets; + hash = bucket_hash(h, key); e = hash_scan(h, hash, key); if (!e) return NULL; @@ -518,7 +530,7 @@ void* hashmap_get2(Hashmap *h, const void *key, void **key2) { if (!h) return NULL; - hash = h->hash_func(key) % h->n_buckets; + hash = bucket_hash(h, key); e = hash_scan(h, hash, key); if (!e) return NULL; @@ -535,12 +547,8 @@ bool hashmap_contains(Hashmap *h, const void *key) { if (!h) return false; - hash = h->hash_func(key) % h->n_buckets; - - if (!hash_scan(h, hash, key)) - return false; - - return true; + hash = bucket_hash(h, key); + return !!hash_scan(h, hash, key); } void* hashmap_remove(Hashmap *h, const void *key) { @@ -551,12 +559,40 @@ void* hashmap_remove(Hashmap *h, const void *key) { if (!h) return NULL; - hash = h->hash_func(key) % h->n_buckets; + hash = bucket_hash(h, key); + e = hash_scan(h, hash, key); + if (!e) + return NULL; + + data = e->value; + remove_entry(h, e); + + return data; +} + +void* hashmap_remove2(Hashmap *h, const void *key, void **rkey) { + struct hashmap_entry *e; + unsigned hash; + void *data; + + if (!h) { + if (rkey) + *rkey = NULL; + return NULL; + } - if (!(e = hash_scan(h, hash, key))) + hash = bucket_hash(h, key); + e = hash_scan(h, hash, key); + if (!e) { + if (rkey) + *rkey = NULL; return NULL; + } data = e->value; + if (rkey) + *rkey = (void*) e->key; + remove_entry(h, e); return data; @@ -569,11 +605,12 @@ int hashmap_remove_and_put(Hashmap *h, const void *old_key, const void *new_key, if (!h) return -ENOENT; - old_hash = h->hash_func(old_key) % h->n_buckets; - if (!(e = hash_scan(h, old_hash, old_key))) + old_hash = bucket_hash(h, old_key); + e = hash_scan(h, old_hash, old_key); + if (!e) return -ENOENT; - new_hash = h->hash_func(new_key) % h->n_buckets; + new_hash = bucket_hash(h, new_key); if (hash_scan(h, new_hash, new_key)) return -EEXIST; @@ -594,12 +631,14 @@ int hashmap_remove_and_replace(Hashmap *h, const void *old_key, const void *new_ if (!h) return -ENOENT; - old_hash = h->hash_func(old_key) % h->n_buckets; - if (!(e = hash_scan(h, old_hash, old_key))) + old_hash = bucket_hash(h, old_key); + e = hash_scan(h, old_hash, old_key); + if (!e) return -ENOENT; - new_hash = h->hash_func(new_key) % h->n_buckets; - if ((k = hash_scan(h, new_hash, new_key))) + new_hash = bucket_hash(h, new_key); + k = hash_scan(h, new_hash, new_key); + if (k) if (e != k) remove_entry(h, k); @@ -620,7 +659,7 @@ void* hashmap_remove_value(Hashmap *h, const void *key, void *value) { if (!h) return NULL; - hash = h->hash_func(key) % h->n_buckets; + hash = bucket_hash(h, key); e = hash_scan(h, hash, key); if (!e) @@ -669,59 +708,6 @@ at_end: return NULL; } -void *hashmap_iterate_backwards(Hashmap *h, Iterator *i, const void **key) { - struct hashmap_entry *e; - - assert(i); - - if (!h) - goto at_beginning; - - if (*i == ITERATOR_FIRST) - goto at_beginning; - - if (*i == ITERATOR_LAST && !h->iterate_list_tail) - goto at_beginning; - - e = *i == ITERATOR_LAST ? h->iterate_list_tail : (struct hashmap_entry*) *i; - - if (e->iterate_previous) - *i = (Iterator) e->iterate_previous; - else - *i = ITERATOR_FIRST; - - if (key) - *key = e->key; - - return e->value; - -at_beginning: - *i = ITERATOR_FIRST; - - if (key) - *key = NULL; - - return NULL; -} - -void *hashmap_iterate_skip(Hashmap *h, const void *key, Iterator *i) { - unsigned hash; - struct hashmap_entry *e; - - if (!h) - return NULL; - - hash = h->hash_func(key) % h->n_buckets; - - e = hash_scan(h, hash, key); - if (!e) - return NULL; - - *i = (Iterator) e; - - return e->value; -} - void* hashmap_first(Hashmap *h) { if (!h) @@ -744,17 +730,6 @@ void* hashmap_first_key(Hashmap *h) { return (void*) h->iterate_list_head->key; } -void* hashmap_last(Hashmap *h) { - - if (!h) - return NULL; - - if (!h->iterate_list_tail) - return NULL; - - return h->iterate_list_tail->value; -} - void* hashmap_steal_first(Hashmap *h) { void *data; @@ -820,14 +795,26 @@ int hashmap_merge(Hashmap *h, Hashmap *other) { for (e = other->iterate_list_head; e; e = e->iterate_next) { int r; - if ((r = hashmap_put(h, e->key, e->value)) < 0) - if (r != -EEXIST) - return r; + r = hashmap_put(h, e->key, e->value); + if (r < 0 && r != -EEXIST) + return r; } return 0; } +int hashmap_reserve(Hashmap *h, unsigned entries_add) { + int r; + + assert(h); + + r = resize_buckets(h, entries_add); + if (r < 0) + return r; + + return 0; +} + void hashmap_move(Hashmap *h, Hashmap *other) { struct hashmap_entry *e, *n; @@ -844,13 +831,11 @@ void hashmap_move(Hashmap *h, Hashmap *other) { n = e->iterate_next; - h_hash = h->hash_func(e->key) % h->n_buckets; - + h_hash = bucket_hash(h, e->key); if (hash_scan(h, h_hash, e->key)) continue; - other_hash = other->hash_func(e->key) % other->n_buckets; - + other_hash = bucket_hash(other, e->key); unlink_entry(other, e, other_hash); link_entry(h, e, h_hash); } @@ -860,16 +845,16 @@ int hashmap_move_one(Hashmap *h, Hashmap *other, const void *key) { unsigned h_hash, other_hash; struct hashmap_entry *e; - if (!other) - return 0; - assert(h); - h_hash = h->hash_func(key) % h->n_buckets; + h_hash = bucket_hash(h, key); if (hash_scan(h, h_hash, key)) return -EEXIST; - other_hash = other->hash_func(key) % other->n_buckets; + if (!other) + return -ENOENT; + + other_hash = bucket_hash(other, key); e = hash_scan(other, other_hash, key); if (!e) return -ENOENT; @@ -885,7 +870,7 @@ Hashmap *hashmap_copy(Hashmap *h) { assert(h); - copy = hashmap_new(h->hash_func, h->compare_func); + copy = hashmap_new(h->hash_ops); if (!copy) return NULL; @@ -919,13 +904,12 @@ void *hashmap_next(Hashmap *h, const void *key) { unsigned hash; struct hashmap_entry *e; - assert(h); assert(key); if (!h) return NULL; - hash = h->hash_func(key) % h->n_buckets; + hash = bucket_hash(h, key); e = hash_scan(h, hash, key); if (!e) return NULL;