diff options
Diffstat (limited to 'src/sys/os/os_ns.c')
| -rw-r--r-- | src/sys/os/os_ns.c | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/src/sys/os/os_ns.c b/src/sys/os/os_ns.c new file mode 100644 index 0000000..2e0426f --- /dev/null +++ b/src/sys/os/os_ns.c @@ -0,0 +1,200 @@ +/* + * 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); + 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 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) { + *((void **)res_p) = entry->data; + return 0; + } + + hm = hm->next; + } + + return -ENOENT; +} + +/* + * Initialize the namespace + */ +int +ns_init(void) +{ + memset(&namespace, 0, sizeof(namespace)); + return 0; +} |