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/*
* Copyright (c) 2025 Ian Marco Moffett and L5 engineers
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the project nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Description: System object namespace
* Author: Ian Marco Moffett
*/
#include <sys/errno.h>
#include <sys/param.h>
#include <os/nsvar.h>
#include <os/ns.h>
#include <string.h>
#define NS_HM_ENTRIES 16
/* Name space object hashmap entry */
struct hashmap_entry {
void *data;
char *name;
uint32_t key;
};
/* Namespace object hashmap */
struct ns_hashmap {
struct hashmap_entry entries[NS_HM_ENTRIES];
size_t entry_count;
struct ns_hashmap *next;
};
/* Global namespace */
static struct ns_hashmap namespace;
/*
* Fowler–Noll–Vo hash function
*
* @s: String to hash
*/
static uint32_t
fnv1_hash(const char *s)
{
uint32_t hash = 2166136261UL;
const uint8_t *p = (uint8_t *)s;
while (*p != '\0') {
hash ^= *p;
hash = hash * 0x01000193;
++p;
}
return hash;
}
/*
* Initialize an object
*/
int
ns_obj_init(struct ns_obj *nsop)
{
if (nsop == NULL) {
return -EINVAL;
}
memset(nsop, 0, sizeof(*nsop));
nsop->refcount = 1;
return 0;
}
/*
* Read data from an object
*/
ssize_t
ns_obj_read(struct ns_obj *nsop, void *buf, off_t off, size_t len)
{
if (nsop == NULL || buf == NULL) {
return -EINVAL;
}
if (len == 0) {
return -EINVAL;
}
/*
* Prefer read() but fallback to data if we
* need to
*/
if (nsop->read == NULL && nsop->data != NULL) {
memcpy(buf, nsop->data, len);
}
return len;
}
/*
* Place an object into the namespace
*/
int
ns_obj_enter(ns_t ns, void *obj, const char *name)
{
uint32_t hash, key;
struct ns_hashmap *hm;
struct hashmap_entry *entry;
if (obj == NULL || name == NULL) {
return -EINVAL;
}
/* Get the index */
hash = fnv1_hash(name);
key = hash % NS_HM_ENTRIES;
/* Find a free slot */
hm = &namespace;
while (hm != NULL) {
entry = &hm->entries[key];
if (entry->data == NULL) {
entry->data = obj;
entry->name = strdup(name);
++hm->entry_count;
return 0;
}
hm = hm->next;
}
return 0;
}
/*
* Look up and object within the namespace
*/
int
ns_obj_lookup(ns_t ns, const char *name, void *res_p)
{
uint32_t hash, key;
struct ns_hashmap *hm;
struct ns_obj *obj;
struct hashmap_entry *entry;
if (name == NULL || res_p == NULL) {
return -EINVAL;
}
/* Get the index */
hash = fnv1_hash(name);
key = hash % NS_HM_ENTRIES;
hm = &namespace;
while (hm != NULL) {
entry = &hm->entries[key];
if (entry->name == NULL) {
hm = hm->next;
continue;
}
if (strcmp(entry->name, name) == 0) {
if ((obj = entry->data) == NULL)
continue;
if (obj->data == NULL)
continue;
*((void **)res_p) = obj->data;
return 0;
}
hm = hm->next;
}
return -ENOENT;
}
/*
* Initialize the namespace
*/
int
ns_init(void)
{
memset(&namespace, 0, sizeof(namespace));
return 0;
}
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