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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/namei.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/errno.h>
#include <vm/dynalloc.h>
#include <string.h>
/*
* Fetches the filename within a path at
* the nth index denoted by `idx'
*
* Returns memory allocated by dynalloc()
* containing the filename.
*
* XXX: MUST FREE RETURN VALUE WITH dynfree() WHEN
* DONE!
*/
static char *
vfs_get_fname_at(const char *path, size_t idx)
{
size_t pathlen = strlen(path);
size_t fname_len;
char *path_tmp = dynalloc(pathlen + 2);
char *ret = NULL;
char *start_ptr, *ptr;
/* Make one-based */
++idx;
if (path_tmp == NULL) {
return NULL;
}
ptr = path_tmp;
memcpy(path_tmp, path, pathlen + 1);
/*
* We want to by default have a '/' at the end
* to keep the parsing logic from getting more
* complicated than it needs to be.
*/
path_tmp[pathlen] = '/';
path_tmp[pathlen + 1] = '\0';
/* Skip any leading slashes */
while (*ptr == '/')
++ptr;
start_ptr = ptr;
/* Get each filename */
while (*ptr != '\0') {
/* Handle duplicate delimiter */
if (*ptr == '/' && *(ptr + 1) == '/') {
/*
* Snip this delimiter and skip, the next
* will be read and filename returned (if of course
* the index is reached).
*/
*(ptr++) = '\0';
continue;
}
if (*ptr == '/') {
*(ptr++) = '\0';
/* Continue if index not reached */
if ((--idx) != 0) {
start_ptr = ptr;
continue;
}
/* Index has been reached, start_ptr contains name */
fname_len = strlen(start_ptr);
ret = dynalloc(fname_len + 1);
if (ret != NULL) {
memcpy(ret, start_ptr, fname_len + 1);
}
break;
}
++ptr;
}
dynfree(path_tmp);
return ret;
}
/*
* Search for a path within a mountpoint.
*
* @mp: Mountpoint to search in.
* @path: Path to search for.
*/
static struct vnode *
namei_mp_search(struct mount *mp, const char *path)
{
struct vop_lookup_args lookup_args;
struct vnode *vp = mp->vp;
char *name;
int status;
for (size_t i = 1;; ++i) {
name = vfs_get_fname_at(path, i);
if (name == NULL)
break;
lookup_args.name = name;
lookup_args.dirvp = vp;
lookup_args.vpp = &vp;
status = vfs_vop_lookup(vp, &lookup_args);
dynfree(name);
if (status == 0)
return vp;
}
return NULL;
}
/*
* Convert a path to a vnode.
*
* @ndp: Nameidata containing the path and resulting
* vnode.
*/
int
namei(struct nameidata *ndp)
{
struct vnode *vp = NULL;
struct mount *mp;
struct vop_lookup_args lookup_args;
const char *path = ndp->path;
char *name;
int status;
if (path == NULL) {
return -EINVAL;
}
/* Path must start with "/" */
if (*path != '/') {
return -EINVAL;
}
/* Just return the root vnode if we can */
if (strcmp(path, "/") == 0) {
ndp->vp = g_root_vnode;
return 0;
}
/*
* Start looking at the root vnode. If we can't find
* what we are looking for, we'll try traversing the
* mountlist.
*
* Some filesystems (like initramfs) may only understand
* full paths, so try passing it through.
*/
lookup_args.name = path;
lookup_args.dirvp = g_root_vnode;
lookup_args.vpp = &vp;
status = vfs_vop_lookup(lookup_args.dirvp, &lookup_args);
/* Did we find it in the root */
if (status == 0) {
ndp->vp = vp;
return 0;
}
/* Look through the mountlist */
TAILQ_FOREACH(mp, &g_mountlist, mnt_list) {
/* If it is unamed, can't do anything */
if (mp->name == NULL)
continue;
lookup_args.dirvp = mp->vp;
name = vfs_get_fname_at(path, 0);
/* If the name matches, search within */
if (strcmp(mp->name, name) == 0)
vp = namei_mp_search(mp, path);
/* Did we find it at this mountpoint? */
if (vp != NULL) {
ndp->vp = vp;
return 0;
}
dynfree(name);
}
return -ENOENT;
}
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