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/*
* Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
* 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 Hyra 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.
*/
#include <sys/types.h>
#include <sys/vfs.h>
#include <sys/errno.h>
#include <sys/mount.h>
#include <vm/dynalloc.h>
#include <string.h>
/* FNV-1a defines */
#define FNV_OFFSET 14695981039346656037ULL
#define FNV_PRIME 1099511628211ULL
/*
* 32-bit FNV-1a hash function
* https://en.wikipedia.org/wiki/Fowler–Noll–Vo_hash_function
*/
static size_t
vfs_hash(const char *data)
{
size_t hash = FNV_OFFSET;
const char *p = data;
while (*p) {
hash ^= (size_t)(uint8_t)(*p);
hash *= FNV_PRIME;
++p;
}
return hash;
}
/*
* Hashes a path
*
* @path: Path to hash.
*
* Returns 0 on failure, non-zero return values
* are valid.
*/
size_t
vfs_hash_path(const char *path)
{
char *name = NULL;
size_t i = 0, hash = 0;
if (strcmp(path, "/") == 0 || !vfs_is_valid_path(path)) {
return 0;
} else if (*path != '/') {
return 0;
}
while (name != NULL) {
name = vfs_get_fname_at(path, i++);
if (name != NULL) {
hash += vfs_hash(name);
dynfree(name);
}
}
return hash;
}
/*
* This function checks if a path is valid.
*
* @path: Path to check.
*
* Returns true if valid, otherwise false.
*/
bool
vfs_is_valid_path(const char *path)
{
const char *ptr = path;
char c;
while (*ptr != '\0') {
c = *(ptr++);
switch (c) {
case '/':
case '-':
case '_':
/* Valid char, can continue */
continue;
default:
/*
* This could be an alphabetical or "numeric" char which
* is valid. We want to handle this too. To make things
* easier we'll OR the char by 0x20 to convert it to
* lowercase if it is alphabetical.
*/
c |= 0x20;
if (c >= 'a' && c <= 'z')
continue;
else if (c >= '0' && c <= '9')
continue;
/* We got an invalid char */
return false;
}
}
return true;
}
/*
* Allocates a vnode
*
* @vnode: Pointer to vnode pointer where newly allocated
* vnode will be stored.
*
* @mp: Mountpoint this vnode is associated with.
* @type: Vnode type.
*
* This function will return 0 upon success and < 0 on failure.
*/
int
vfs_alloc_vnode(struct vnode **vnode, struct mount *mp, int type)
{
struct vnode *new_vnode = dynalloc(sizeof(struct vnode));
if (new_vnode == NULL) {
return -ENOMEM;
}
memset(new_vnode, 0, sizeof(struct vnode));
new_vnode->type = type;
new_vnode->mp = mp;
*vnode = new_vnode;
return 0;
}
/*
* This function mounts a `mount' structure
* at a specific path.
*
* @mp_out: Where to store copy of new mountpoint (NULL if none)
* @path: Path to mount on.
* @mnt_flags: Mount flags (MNT_* from sys/mount.h)
*
* Returns 0 upon success, otherwise a < 0 value.
*
* XXX: This function assumes the mountpoint has its mount
* routine set in its vfsops.
*/
int
vfs_mount(struct mount **mp_out, const char *path, int mnt_flags)
{
struct mount *mp;
int cache_status;
mp = dynalloc(sizeof(struct mount));
if (mp == NULL) {
return -ENOMEM;
}
mp->flags = mnt_flags;
cache_status = vfs_cache_mp(mp, path);
if (cache_status != 0) {
dynfree(mp);
return cache_status;
}
*mp_out = mp;
return 0;
}
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