ardix/kernel/fs/file.c

126 lines
2.5 KiB
C

/* See the end of this file for copyright, license, and warranty information. */
#include <ardix/device.h>
#include <ardix/file.h>
#include <ardix/malloc.h>
#include <config.h>
#include <errno.h>
#include <stddef.h>
static struct file *fdtab[CONFIG_NFILE];
static MUTEX(fdtab_lock);
static void file_destroy(struct kent *kent)
{
struct file *file = container_of(kent, struct file, kent);
mutex_lock(&fdtab_lock);
fdtab[file->fd] = NULL;
mutex_unlock(&fdtab_lock);
free(file);
}
struct file *file_create(struct device *device, enum file_type type, int *err)
{
struct file *f;
struct file **slot;
int fd;
mutex_lock(&fdtab_lock);
for (fd = 0; fd < CONFIG_NFILE; fd++) {
slot = &fdtab[fd];
if (*slot == NULL)
break;
}
if (*slot != NULL) {
*err = -EMFILE;
mutex_unlock(&fdtab_lock);
return NULL;
}
f = malloc(sizeof(*f));
if (f == NULL) {
*err = -ENOMEM;
mutex_unlock(&fdtab_lock);
return NULL;
}
*slot = f;
mutex_unlock(&fdtab_lock);
f->kent.parent = &device->kent;
f->kent.destroy = file_destroy;
kent_init(&f->kent);
f->fd = fd;
f->device = device;
f->pos = 0;
f->type = type;
mutex_init(&f->lock);
return f;
}
struct file *file_get(int fd)
{
struct file *f = NULL;
if (fd < CONFIG_NFILE) {
mutex_lock(&fdtab_lock);
f = fdtab[fd];
if (f != NULL)
kent_get(&f->kent);
mutex_unlock(&fdtab_lock);
}
return f;
}
void file_put(struct file *f)
{
kent_put(&f->kent);
}
ssize_t file_read(void *buf, struct file *file, size_t len)
{
ssize_t ret = mutex_trylock(&file->lock);
if (ret == 0) {
ret = file->device->read(buf, file->device, len, file->pos);
if (file->type == FILE_TYPE_REGULAR && ret > 0)
file->pos += ret;
mutex_unlock(&file->lock);
}
return ret;
}
ssize_t file_write(struct file *file, const void *buf, size_t len)
{
ssize_t ret = mutex_trylock(&file->lock);
if (ret == 0) {
ret = file->device->write(file->device, buf, len, file->pos);
if (file->type == FILE_TYPE_REGULAR && ret > 0)
file->pos += ret;
mutex_unlock(&file->lock);
}
return ret;
}
/*
* This file is part of Ardix.
* Copyright (c) 2020, 2021 Felix Kopp <owo@fef.moe>.
*
* Ardix is non-violent software: you may only use, redistribute,
* and/or modify it under the terms of the CNPLv6+ as found in
* the LICENSE file in the source code root directory or at
* <https://git.pixie.town/thufie/CNPL>.
*
* Ardix comes with ABSOLUTELY NO WARRANTY, to the extent
* permitted by applicable law. See the CNPLv6+ for details.
*/