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rt-thread-official/components/dfs/filesystems/ramfs/dfs_ramfs.c

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/*
* File : dfs_ramfs.c
* This file is part of Device File System in RT-Thread RTOS
* COPYRIGHT (C) 2004-2013, RT-Thread Development Team
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Change Logs:
* Date Author Notes
* 2013-04-15 Bernard the first version
* 2013-05-05 Bernard remove CRC for ramfs persistence
* 2013-05-22 Bernard fix the no entry issue.
*/
#include <rtthread.h>
#include <dfs.h>
#include <dfs_fs.h>
#include <dfs_file.h>
#include "dfs_ramfs.h"
int dfs_ramfs_mount(struct dfs_filesystem *fs,
unsigned long rwflag,
const void *data)
{
struct dfs_ramfs* ramfs;
if (data == NULL)
return -EIO;
ramfs = (struct dfs_ramfs *)data;
fs->data = ramfs;
return RT_EOK;
}
int dfs_ramfs_unmount(struct dfs_filesystem *fs)
{
fs->data = NULL;
return RT_EOK;
}
int dfs_ramfs_statfs(struct dfs_filesystem *fs, struct statfs *buf)
{
struct dfs_ramfs *ramfs;
ramfs = (struct dfs_ramfs *)fs->data;
RT_ASSERT(ramfs != NULL);
RT_ASSERT(buf != NULL);
buf->f_bsize = 512;
buf->f_blocks = ramfs->memheap.pool_size/512;
buf->f_bfree = ramfs->memheap.available_size/512;
return RT_EOK;
}
int dfs_ramfs_ioctl(struct dfs_fd *file, int cmd, void *args)
{
return -EIO;
}
struct ramfs_dirent *dfs_ramfs_lookup(struct dfs_ramfs *ramfs,
const char *path,
rt_size_t *size)
{
const char *subpath;
struct ramfs_dirent *dirent;
subpath = path;
while (*subpath == '/' && *subpath)
subpath ++;
if (! *subpath) /* is root directory */
{
*size = 0;
return &(ramfs->root);
}
for (dirent = rt_list_entry(ramfs->root.list.next, struct ramfs_dirent, list);
dirent != &(ramfs->root);
dirent = rt_list_entry(dirent->list.next, struct ramfs_dirent, list))
{
if (rt_strcmp(dirent->name, subpath) == 0)
{
*size = dirent->size;
return dirent;
}
}
/* not found */
return NULL;
}
int dfs_ramfs_read(struct dfs_fd *file, void *buf, size_t count)
{
rt_size_t length;
struct ramfs_dirent *dirent;
dirent = (struct ramfs_dirent *)file->data;
RT_ASSERT(dirent != NULL);
if (count < file->size - file->pos)
length = count;
else
length = file->size - file->pos;
if (length > 0)
memcpy(buf, &(dirent->data[file->pos]), length);
/* update file current position */
file->pos += length;
return length;
}
int dfs_ramfs_write(struct dfs_fd *fd, const void *buf, size_t count)
{
struct ramfs_dirent *dirent;
struct dfs_ramfs *ramfs;
dirent = (struct ramfs_dirent*)fd->data;
RT_ASSERT(dirent != NULL);
ramfs = dirent->fs;
RT_ASSERT(ramfs != NULL);
if (count + fd->pos > fd->size)
{
rt_uint8_t *ptr;
ptr = rt_memheap_realloc(&(ramfs->memheap), dirent->data, fd->pos + count);
if (ptr == NULL)
{
rt_set_errno(-ENOMEM);
return 0;
}
/* update dirent and file size */
dirent->data = ptr;
dirent->size = fd->pos + count;
fd->size = dirent->size;
}
if (count > 0)
memcpy(dirent->data + fd->pos, buf, count);
/* update file current position */
fd->pos += count;
return count;
}
int dfs_ramfs_lseek(struct dfs_fd *file, off_t offset)
{
if (offset <= (off_t)file->size)
{
file->pos = offset;
return file->pos;
}
return -EIO;
}
int dfs_ramfs_close(struct dfs_fd *file)
{
file->data = NULL;
return RT_EOK;
}
int dfs_ramfs_open(struct dfs_fd *file)
{
rt_size_t size;
struct dfs_ramfs *ramfs;
struct ramfs_dirent *dirent;
struct dfs_filesystem *fs;
fs = (struct dfs_filesystem *)file->data;
ramfs = (struct dfs_ramfs *)fs->data;
RT_ASSERT(ramfs != NULL);
if (file->flags & O_DIRECTORY)
{
if (file->flags & O_CREAT)
{
return -ENOSPC;
}
/* open directory */
dirent = dfs_ramfs_lookup(ramfs, file->path, &size);
if (dirent == NULL)
return -ENOENT;
if (dirent == &(ramfs->root)) /* it's root directory */
{
if (!(file->flags & O_DIRECTORY))
{
return -ENOENT;
}
}
}
else
{
dirent = dfs_ramfs_lookup(ramfs, file->path, &size);
if (dirent == &(ramfs->root)) /* it's root directory */
{
return -ENOENT;
}
if (dirent == NULL)
{
if (file->flags & O_CREAT || file->flags & O_WRONLY)
{
char *name_ptr;
/* create a file entry */
dirent = (struct ramfs_dirent *)
rt_memheap_alloc(&(ramfs->memheap),
sizeof(struct ramfs_dirent));
if (dirent == NULL)
{
return -ENOMEM;
}
/* remove '/' separator */
name_ptr = file->path;
while (*name_ptr == '/' && *name_ptr)
name_ptr ++;
strncpy(dirent->name, name_ptr, RAMFS_NAME_MAX);
rt_list_init(&(dirent->list));
dirent->data = NULL;
dirent->size = 0;
dirent->fs = ramfs;
/* add to the root directory */
rt_list_insert_after(&(ramfs->root.list), &(dirent->list));
}
else
return -ENOENT;
}
/* Creates a new file.
* If the file is existing, it is truncated and overwritten.
*/
if (file->flags & O_TRUNC)
{
dirent->size = 0;
if (dirent->data != NULL)
{
rt_memheap_free(dirent->data);
dirent->data = NULL;
}
}
}
file->data = dirent;
file->size = dirent->size;
if (file->flags & O_APPEND)
file->pos = file->size;
else
file->pos = 0;
return 0;
}
int dfs_ramfs_stat(struct dfs_filesystem *fs,
const char *path,
struct stat *st)
{
rt_size_t size;
struct ramfs_dirent *dirent;
struct dfs_ramfs *ramfs;
ramfs = (struct dfs_ramfs *)fs->data;
dirent = dfs_ramfs_lookup(ramfs, path, &size);
if (dirent == NULL)
return -ENOENT;
st->st_dev = 0;
st->st_mode = S_IFREG | S_IRUSR | S_IRGRP | S_IROTH |
S_IWUSR | S_IWGRP | S_IWOTH;
st->st_size = dirent->size;
st->st_mtime = 0;
return RT_EOK;
}
int dfs_ramfs_getdents(struct dfs_fd *file,
struct dirent *dirp,
uint32_t count)
{
rt_size_t index, end;
struct dirent *d;
struct ramfs_dirent *dirent;
struct dfs_ramfs *ramfs;
dirent = (struct ramfs_dirent *)file->data;
ramfs = dirent->fs;
RT_ASSERT(ramfs != RT_NULL);
if (dirent != &(ramfs->root))
return -EINVAL;
/* make integer count */
count = (count / sizeof(struct dirent));
if (count == 0)
return -EINVAL;
end = file->pos + count;
index = 0;
count = 0;
for (dirent = rt_list_entry(dirent->list.next, struct ramfs_dirent, list);
dirent != &(ramfs->root) && index < end;
dirent = rt_list_entry(dirent->list.next, struct ramfs_dirent, list))
{
if (index >= (rt_size_t)file->pos)
{
d = dirp + count;
d->d_type = DT_REG;
d->d_namlen = RT_NAME_MAX;
d->d_reclen = (rt_uint16_t)sizeof(struct dirent);
rt_strncpy(d->d_name, dirent->name, RAMFS_NAME_MAX);
count += 1;
file->pos += 1;
}
index += 1;
}
return count * sizeof(struct dirent);
}
int dfs_ramfs_unlink(struct dfs_filesystem *fs, const char *path)
{
rt_size_t size;
struct dfs_ramfs *ramfs;
struct ramfs_dirent *dirent;
ramfs = (struct dfs_ramfs *)fs->data;
RT_ASSERT(ramfs != NULL);
dirent = dfs_ramfs_lookup(ramfs, path, &size);
if (dirent == NULL)
return -ENOENT;
rt_list_remove(&(dirent->list));
if (dirent->data != NULL)
rt_memheap_free(dirent->data);
rt_memheap_free(dirent);
return RT_EOK;
}
int dfs_ramfs_rename(struct dfs_filesystem *fs,
const char *oldpath,
const char *newpath)
{
struct ramfs_dirent *dirent;
struct dfs_ramfs *ramfs;
rt_size_t size;
ramfs = (struct dfs_ramfs *)fs->data;
RT_ASSERT(ramfs != NULL);
dirent = dfs_ramfs_lookup(ramfs, newpath, &size);
if (dirent != NULL)
return -EEXIST;
dirent = dfs_ramfs_lookup(ramfs, oldpath, &size);
if (dirent == NULL)
return -ENOENT;
strncpy(dirent->name, newpath, RAMFS_NAME_MAX);
return RT_EOK;
}
static const struct dfs_file_ops _ram_fops =
{
dfs_ramfs_open,
dfs_ramfs_close,
dfs_ramfs_ioctl,
dfs_ramfs_read,
dfs_ramfs_write,
NULL, /* flush */
dfs_ramfs_lseek,
dfs_ramfs_getdents,
};
static const struct dfs_filesystem_ops _ramfs =
{
"ram",
DFS_FS_FLAG_DEFAULT,
&_ram_fops,
dfs_ramfs_mount,
dfs_ramfs_unmount,
NULL, /* mkfs */
dfs_ramfs_statfs,
dfs_ramfs_unlink,
dfs_ramfs_stat,
dfs_ramfs_rename,
};
int dfs_ramfs_init(void)
{
/* register ram file system */
dfs_register(&_ramfs);
return 0;
}
INIT_COMPONENT_EXPORT(dfs_ramfs_init);
struct dfs_ramfs* dfs_ramfs_create(rt_uint8_t *pool, rt_size_t size)
{
struct dfs_ramfs *ramfs;
rt_uint8_t *data_ptr;
rt_err_t result;
size = RT_ALIGN_DOWN(size, RT_ALIGN_SIZE);
ramfs = (struct dfs_ramfs *)pool;
data_ptr = (rt_uint8_t *)(ramfs + 1);
size = size - sizeof(struct dfs_ramfs);
size = RT_ALIGN_DOWN(size, RT_ALIGN_SIZE);
result = rt_memheap_init(&ramfs->memheap, "ramfs", data_ptr, size);
if (result != RT_EOK)
return NULL;
/* detach this memheap object from the system */
rt_object_detach((rt_object_t)&(ramfs->memheap));
/* initialize ramfs object */
ramfs->magic = RAMFS_MAGIC;
/* initialize root directory */
memset(&(ramfs->root), 0x00, sizeof(ramfs->root));
rt_list_init(&(ramfs->root.list));
ramfs->root.size = 0;
strcpy(ramfs->root.name, ".");
ramfs->root.fs = ramfs;
return ramfs;
}
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