Merge branch 'rightlib' into mergelibs-241019-1758

1 files changed, 447 insertions, 0 deletions

diff --git a/contrib/libs/c-ares/src/lib/dsa/ares_htable.c b/contrib/libs/c-ares/src/lib/dsa/ares_htable.c
new file mode 100644
index 0000000000..f76b67cae9
--- /dev/null
+++ b/contrib/libs/c-ares/src/lib/dsa/ares_htable.c
@@ -0,0 +1,447 @@
+/* MIT License
+ *
+ * Copyright (c) 2023 Brad House
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * SPDX-License-Identifier: MIT
+ */
+#include "ares_private.h"
+#include "ares_llist.h"
+#include "ares_htable.h"
+
+#define ARES__HTABLE_MAX_BUCKETS    (1U << 24)
+#define ARES__HTABLE_MIN_BUCKETS    (1U << 4)
+#define ARES__HTABLE_EXPAND_PERCENT 75
+
+struct ares_htable {
+  ares_htable_hashfunc_t    hash;
+  ares_htable_bucket_key_t  bucket_key;
+  ares_htable_bucket_free_t bucket_free;
+  ares_htable_key_eq_t      key_eq;
+  unsigned int              seed;
+  unsigned int              size;
+  size_t                    num_keys;
+  size_t                    num_collisions;
+  /* NOTE: if we converted buckets into ares_slist_t we could guarantee on
+   *       hash collisions we would have O(log n) worst case insert and search
+   *       performance.  (We'd also need to make key_eq into a key_cmp to
+   *       support sort).  That said, risk with a random hash seed is near zero,
+   *       and ares_slist_t is heavier weight, so I think using ares_llist_t
+   *       is an overall win. */
+  ares_llist_t            **buckets;
+};
+
+static unsigned int ares_htable_generate_seed(ares_htable_t *htable)
+{
+#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
+  /* Seed needs to be static for fuzzing */
+  return 0;
+#else
+  unsigned int seed = 0;
+  time_t       t    = time(NULL);
+
+  /* Mix stack address, heap address, and time to generate a random seed, it
+   * doesn't have to be super secure, just quick.  Likelihood of a hash
+   * collision attack is very low with a small amount of effort */
+  seed |= (unsigned int)((size_t)htable & 0xFFFFFFFF);
+  seed |= (unsigned int)((size_t)&seed & 0xFFFFFFFF);
+  seed |= (unsigned int)(((ares_uint64_t)t) & 0xFFFFFFFF);
+  return seed;
+#endif
+}
+
+static void ares_htable_buckets_destroy(ares_llist_t **buckets,
+                                        unsigned int   size,
+                                        ares_bool_t    destroy_vals)
+{
+  unsigned int i;
+
+  if (buckets == NULL) {
+    return;
+  }
+
+  for (i = 0; i < size; i++) {
+    if (buckets[i] == NULL) {
+      continue;
+    }
+
+    if (!destroy_vals) {
+      ares_llist_replace_destructor(buckets[i], NULL);
+    }
+
+    ares_llist_destroy(buckets[i]);
+  }
+
+  ares_free(buckets);
+}
+
+void ares_htable_destroy(ares_htable_t *htable)
+{
+  if (htable == NULL) {
+    return;
+  }
+  ares_htable_buckets_destroy(htable->buckets, htable->size, ARES_TRUE);
+  ares_free(htable);
+}
+
+ares_htable_t *ares_htable_create(ares_htable_hashfunc_t    hash_func,
+                                  ares_htable_bucket_key_t  bucket_key,
+                                  ares_htable_bucket_free_t bucket_free,
+                                  ares_htable_key_eq_t      key_eq)
+{
+  ares_htable_t *htable = NULL;
+
+  if (hash_func == NULL || bucket_key == NULL || bucket_free == NULL ||
+      key_eq == NULL) {
+    goto fail;
+  }
+
+  htable = ares_malloc_zero(sizeof(*htable));
+  if (htable == NULL) {
+    goto fail;
+  }
+
+  htable->hash        = hash_func;
+  htable->bucket_key  = bucket_key;
+  htable->bucket_free = bucket_free;
+  htable->key_eq      = key_eq;
+  htable->seed        = ares_htable_generate_seed(htable);
+  htable->size        = ARES__HTABLE_MIN_BUCKETS;
+  htable->buckets = ares_malloc_zero(sizeof(*htable->buckets) * htable->size);
+
+  if (htable->buckets == NULL) {
+    goto fail;
+  }
+
+  return htable;
+
+fail:
+  ares_htable_destroy(htable);
+  return NULL;
+}
+
+const void **ares_htable_all_buckets(const ares_htable_t *htable, size_t *num)
+{
+  const void **out = NULL;
+  size_t       cnt = 0;
+  size_t       i;
+
+  if (htable == NULL || num == NULL) {
+    return NULL; /* LCOV_EXCL_LINE */
+  }
+
+  *num = 0;
+
+  out = ares_malloc_zero(sizeof(*out) * htable->num_keys);
+  if (out == NULL) {
+    return NULL; /* LCOV_EXCL_LINE */
+  }
+
+  for (i = 0; i < htable->size; i++) {
+    ares_llist_node_t *node;
+    for (node = ares_llist_node_first(htable->buckets[i]); node != NULL;
+         node = ares_llist_node_next(node)) {
+      out[cnt++] = ares_llist_node_val(node);
+    }
+  }
+
+  *num = cnt;
+  return out;
+}
+
+/*! Grabs the Hashtable index from the key and length.  The h index is
+ *  the hash of the function reduced to the size of the bucket list.
+ *  We are doing "hash & (size - 1)" since we are guaranteeing a power of
+ *  2 for size. This is equivalent to "hash % size", but should be more
+ * efficient */
+#define HASH_IDX(h, key) h->hash(key, h->seed) & (h->size - 1)
+
+static ares_llist_node_t *ares_htable_find(const ares_htable_t *htable,
+                                           unsigned int idx, const void *key)
+{
+  ares_llist_node_t *node = NULL;
+
+  for (node = ares_llist_node_first(htable->buckets[idx]); node != NULL;
+       node = ares_llist_node_next(node)) {
+    if (htable->key_eq(key, htable->bucket_key(ares_llist_node_val(node)))) {
+      break;
+    }
+  }
+
+  return node;
+}
+
+static ares_bool_t ares_htable_expand(ares_htable_t *htable)
+{
+  ares_llist_t **buckets  = NULL;
+  unsigned int   old_size = htable->size;
+  size_t         i;
+  ares_llist_t **prealloc_llist     = NULL;
+  size_t         prealloc_llist_len = 0;
+  ares_bool_t    rv                 = ARES_FALSE;
+
+  /* Not a failure, just won't expand */
+  if (old_size == ARES__HTABLE_MAX_BUCKETS) {
+    return ARES_TRUE; /* LCOV_EXCL_LINE */
+  }
+
+  htable->size <<= 1;
+
+  /* We must pre-allocate all memory we'll need before moving entries to the
+   * new hash array.  Otherwise if there's a memory allocation failure in the
+   * middle, we wouldn't be able to recover. */
+  buckets = ares_malloc_zero(sizeof(*buckets) * htable->size);
+  if (buckets == NULL) {
+    goto done; /* LCOV_EXCL_LINE */
+  }
+
+  /* The maximum number of new llists we'll need is the number of collisions
+   * that were recorded */
+  prealloc_llist_len = htable->num_collisions;
+  if (prealloc_llist_len) {
+    prealloc_llist =
+      ares_malloc_zero(sizeof(*prealloc_llist) * prealloc_llist_len);
+    if (prealloc_llist == NULL) {
+      goto done; /* LCOV_EXCL_LINE */
+    }
+  }
+  for (i = 0; i < prealloc_llist_len; i++) {
+    prealloc_llist[i] = ares_llist_create(htable->bucket_free);
+    if (prealloc_llist[i] == NULL) {
+      goto done;
+    }
+  }
+
+  /* Iterate across all buckets and move the entries to the new buckets */
+  htable->num_collisions = 0;
+  for (i = 0; i < old_size; i++) {
+    ares_llist_node_t *node;
+
+    /* Nothing in this bucket */
+    if (htable->buckets[i] == NULL) {
+      continue;
+    }
+
+    /* Fast path optimization (most likely case), there is likely only a single
+     * entry in both the source and destination, check for this to confirm and
+     * if so, just move the bucket over */
+    if (ares_llist_len(htable->buckets[i]) == 1) {
+      const void *val = ares_llist_first_val(htable->buckets[i]);
+      size_t      idx = HASH_IDX(htable, htable->bucket_key(val));
+
+      if (buckets[idx] == NULL) {
+        /* Swap! */
+        buckets[idx]       = htable->buckets[i];
+        htable->buckets[i] = NULL;
+        continue;
+      }
+    }
+
+    /* Slow path, collisions */
+    while ((node = ares_llist_node_first(htable->buckets[i])) != NULL) {
+      const void *val = ares_llist_node_val(node);
+      size_t      idx = HASH_IDX(htable, htable->bucket_key(val));
+
+      /* Try fast path again as maybe we popped one collision off and the
+       * next we can reuse the llist parent */
+      if (buckets[idx] == NULL && ares_llist_len(htable->buckets[i]) == 1) {
+        /* Swap! */
+        buckets[idx]       = htable->buckets[i];
+        htable->buckets[i] = NULL;
+        break;
+      }
+
+      /* Grab one off our preallocated list */
+      if (buckets[idx] == NULL) {
+        /* Silence static analysis, this isn't possible but it doesn't know */
+        if (prealloc_llist == NULL || prealloc_llist_len == 0) {
+          goto done; /* LCOV_EXCL_LINE */
+        }
+        buckets[idx] = prealloc_llist[prealloc_llist_len - 1];
+        prealloc_llist_len--;
+      } else {
+        /* Collision occurred since the bucket wasn't empty */
+        htable->num_collisions++;
+      }
+
+      ares_llist_node_mvparent_first(node, buckets[idx]);
+    }
+
+    /* Abandoned bucket, destroy */
+    if (htable->buckets[i] != NULL) {
+      ares_llist_destroy(htable->buckets[i]);
+      htable->buckets[i] = NULL;
+    }
+  }
+
+  /* We have guaranteed all the buckets have either been moved or destroyed,
+   * so we just call ares_free() on the array and swap out the pointer */
+  ares_free(htable->buckets);
+  htable->buckets = buckets;
+  buckets         = NULL;
+  rv              = ARES_TRUE;
+
+done:
+  ares_free(buckets);
+  /* destroy any unused preallocated buckets */
+  ares_htable_buckets_destroy(prealloc_llist, (unsigned int)prealloc_llist_len,
+                              ARES_FALSE);
+
+  /* On failure, we need to restore the htable size */
+  if (rv != ARES_TRUE) {
+    htable->size = old_size; /* LCOV_EXCL_LINE */
+  }
+
+  return rv;
+}
+
+ares_bool_t ares_htable_insert(ares_htable_t *htable, void *bucket)
+{
+  unsigned int       idx  = 0;
+  ares_llist_node_t *node = NULL;
+  const void        *key  = NULL;
+
+  if (htable == NULL || bucket == NULL) {
+    return ARES_FALSE;
+  }
+
+
+  key = htable->bucket_key(bucket);
+  idx = HASH_IDX(htable, key);
+
+  /* See if we have a matching bucket already, if so, replace it */
+  node = ares_htable_find(htable, idx, key);
+  if (node != NULL) {
+    ares_llist_node_replace(node, bucket);
+    return ARES_TRUE;
+  }
+
+  /* Check to see if we should rehash because likelihood of collisions has
+   * increased beyond our threshold */
+  if (htable->num_keys + 1 >
+      (htable->size * ARES__HTABLE_EXPAND_PERCENT) / 100) {
+    if (!ares_htable_expand(htable)) {
+      return ARES_FALSE; /* LCOV_EXCL_LINE */
+    }
+    /* If we expanded, need to calculate a new index */
+    idx = HASH_IDX(htable, key);
+  }
+
+  /* We lazily allocate the linked list */
+  if (htable->buckets[idx] == NULL) {
+    htable->buckets[idx] = ares_llist_create(htable->bucket_free);
+    if (htable->buckets[idx] == NULL) {
+      return ARES_FALSE;
+    }
+  }
+
+  node = ares_llist_insert_first(htable->buckets[idx], bucket);
+  if (node == NULL) {
+    return ARES_FALSE;
+  }
+
+  /* Track collisions for rehash stability */
+  if (ares_llist_len(htable->buckets[idx]) > 1) {
+    htable->num_collisions++;
+  }
+
+  htable->num_keys++;
+
+  return ARES_TRUE;
+}
+
+void *ares_htable_get(const ares_htable_t *htable, const void *key)
+{
+  unsigned int idx;
+
+  if (htable == NULL || key == NULL) {
+    return NULL;
+  }
+
+  idx = HASH_IDX(htable, key);
+
+  return ares_llist_node_val(ares_htable_find(htable, idx, key));
+}
+
+ares_bool_t ares_htable_remove(ares_htable_t *htable, const void *key)
+{
+  ares_llist_node_t *node;
+  unsigned int       idx;
+
+  if (htable == NULL || key == NULL) {
+    return ARES_FALSE;
+  }
+
+  idx  = HASH_IDX(htable, key);
+  node = ares_htable_find(htable, idx, key);
+  if (node == NULL) {
+    return ARES_FALSE;
+  }
+
+  htable->num_keys--;
+
+  /* Reduce collisions */
+  if (ares_llist_len(ares_llist_node_parent(node)) > 1) {
+    htable->num_collisions--;
+  }
+
+  ares_llist_node_destroy(node);
+  return ARES_TRUE;
+}
+
+size_t ares_htable_num_keys(const ares_htable_t *htable)
+{
+  if (htable == NULL) {
+    return 0;
+  }
+  return htable->num_keys;
+}
+
+unsigned int ares_htable_hash_FNV1a(const unsigned char *key, size_t key_len,
+                                    unsigned int seed)
+{
+  unsigned int hv = seed ^ 2166136261U;
+  size_t       i;
+
+  for (i = 0; i < key_len; i++) {
+    hv ^= (unsigned int)key[i];
+    /* hv *= 16777619 (0x01000193) */
+    hv += (hv << 1) + (hv << 4) + (hv << 7) + (hv << 8) + (hv << 24);
+  }
+
+  return hv;
+}
+
+/* Case insensitive version, meant for ASCII strings */
+unsigned int ares_htable_hash_FNV1a_casecmp(const unsigned char *key,
+                                            size_t key_len, unsigned int seed)
+{
+  unsigned int hv = seed ^ 2166136261U;
+  size_t       i;
+
+  for (i = 0; i < key_len; i++) {
+    hv ^= (unsigned int)ares_tolower(key[i]);
+    /* hv *= 16777619 (0x01000193) */
+    hv += (hv << 1) + (hv << 4) + (hv << 7) + (hv << 8) + (hv << 24);
+  }
+
+  return hv;
+}