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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/atomic.h>
#include <sys/errno.h>
#include <sys/proc.h>
#include <sys/limits.h>
#include <sys/namei.h>
#include <sys/filedesc.h>
#include <sys/systm.h>
#include <vm/dynalloc.h>
#include <string.h>
/*
* Allocate a file descriptor.
*
* @fd_out: Pointer to allocated file descriptor output.
*
* This routine will create a new file descriptor
* table entry.
*
* Returns 0 on success.
*/
int
fd_alloc(struct filedesc **fd_out)
{
struct filedesc *fd;
struct proc *td = this_td();
/* Find free fd table entry */
for (size_t i = 3; i < PROC_MAX_FILEDES; ++i) {
if (td->fds[i] != NULL) {
/* In use */
continue;
}
fd = dynalloc(sizeof(struct filedesc));
memset(fd, 0, sizeof(struct filedesc));
if (fd == NULL) {
return -ENOMEM;
}
fd->refcnt = 1;
fd->fdno = i;
td->fds[i] = fd;
if (fd_out != NULL)
*fd_out = fd;
return 0;
}
return -EMFILE;
}
/*
* Fetch a file descriptor from a file descriptor
* number.
*
* @fdno: File descriptor to fetch
*/
struct filedesc *
fd_get(unsigned int fdno)
{
struct proc *td = this_td();
if (fdno > PROC_MAX_FILEDES) {
return NULL;
}
return td->fds[fdno];
}
/*
* Close a file descriptor with a file
* descriptor number.
*
* @fd: File descriptor number to close.
*/
int
fd_close(unsigned int fd)
{
struct filedesc *filedes;
struct proc *td;
if ((filedes = fd_get(fd)) == NULL) {
return -EBADF;
}
/* Return if other threads still hold a ref */
if (atomic_dec_int(&filedes->refcnt) > 0) {
return 0;
}
td = this_td();
/*
* Each file descriptor structure references a vnode,
* we want to reclaim it or at the very least drop
* one of its references. After we've cleaned up within
* the file descriptor, we can clear it from the fd table
* and free up the memory for it.
*/
vfs_release_vnode(filedes->vp);
td->fds[fd] = NULL;
dynfree(filedes);
return 0;
}
/*
* Read bytes from a file using a file
* descriptor number.
*
* @fd: File descriptor number.
* @buf: Buffer to read into.
* @count: Number of bytes to read.
*/
int
fd_read(unsigned int fd, void *buf, size_t count)
{
char *kbuf = NULL;
struct filedesc *filedes;
struct sio_txn sio;
scret_t retval = 0;
if (count > SSIZE_MAX) {
retval = -EINVAL;
goto done;
}
filedes = fd_get(fd);
kbuf = dynalloc(count);
if (kbuf == NULL) {
retval = -ENOMEM;
goto done;
}
if (filedes == NULL) {
retval = -EBADF;
goto done;
}
if (filedes->is_dir) {
retval = -EISDIR;
goto done;
}
sio.len = count;
sio.buf = kbuf;
sio.offset = filedes->offset;
if ((count = vfs_vop_read(filedes->vp, &sio)) < 0) {
retval = -EIO;
goto done;
}
if (copyout(kbuf, buf, count) < 0) {
retval = -EFAULT;
goto done;
}
retval = count;
done:
if (kbuf != NULL) {
dynfree(kbuf);
}
return retval;
}
/*
* Open a file and get a file descriptor
* number.
*
* @pathname: Path of file to open.
* @flags: Flags to use.
*
* TODO: Use of flags.
*/
int
fd_open(const char *pathname, int flags)
{
int error;
struct filedesc *filedes;
struct nameidata nd;
nd.path = pathname;
nd.flags = 0;
if ((error = namei(&nd)) < 0) {
return error;
}
if ((error = fd_alloc(&filedes)) != 0) {
vfs_release_vnode(nd.vp);
return error;
}
filedes->vp = nd.vp;
return filedes->fdno;
}
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