static int open(struct inode * inode, struct file * file)
{
struct kobject *kobj = sysfs_get_kobject(file->f_dentry->d_parent);
struct bin_attribute * attr = to_bin_attr(file->f_dentry);
int error = -EINVAL;
if (!kobj || !attr)
goto Done;
/* Grab the module reference for this attribute if we have one */
error = -ENODEV;
if (!try_module_get(attr->attr.owner))
goto Done;
error = -EACCES;
if ((file->f_mode & FMODE_WRITE) && !(attr->write || attr->mmap))
goto Error;
if ((file->f_mode & FMODE_READ) && !(attr->read || attr->mmap))
goto Error;
error = -ENOMEM;
file->private_data = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!file->private_data)
goto Error;
error = 0;
goto Done;
Error:
module_put(attr->attr.owner);
Done:
if (error && kobj)
kobject_put(kobj);
return error;
}
static int configfs_release_bin_file(struct inode *inode, struct file *filp)
{
struct configfs_buffer *buffer = filp->private_data;
struct dentry *dentry = filp->f_path.dentry;
struct config_item *item = to_item(dentry->d_parent);
struct configfs_item_operations *ops = buffer->ops;
struct configfs_bin_attribute *bin_attr = to_bin_attr(dentry);
ssize_t len = 0;
int ret;
buffer->read_in_progress = 0;
if (buffer->write_in_progress) {
buffer->write_in_progress = 0;
len = ops->write_bin_attribute(item, bin_attr,
buffer->bin_buffer, buffer->bin_buffer_size);
/* vfree on NULL is safe */
vfree(buffer->bin_buffer);
buffer->bin_buffer = NULL;
buffer->bin_buffer_size = 0;
buffer->needs_read_fill = 1;
}
ret = do_release(inode, filp,
to_item(filp->f_path.dentry->d_parent),
to_attr(filp->f_path.dentry), CONFIGFS_ITEM_BIN_ATTR);
if (len < 0)
return len;
return ret;
}
static ssize_t
configfs_read_bin_file(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
struct configfs_buffer *buffer = file->private_data;
struct dentry *dentry = file->f_path.dentry;
struct config_item *item = to_item(dentry->d_parent);
struct configfs_bin_attribute *bin_attr = to_bin_attr(dentry);
ssize_t retval = 0;
ssize_t len = min_t(size_t, count, PAGE_SIZE);
mutex_lock(&buffer->mutex);
/* we don't support switching read/write modes */
if (buffer->write_in_progress) {
retval = -ETXTBSY;
goto out;
}
buffer->read_in_progress = 1;
if (buffer->needs_read_fill) {
/* perform first read with buf == NULL to get extent */
len = bin_attr->read(item, NULL, 0);
if (len <= 0) {
retval = len;
goto out;
}
/* do not exceed the maximum value */
if (bin_attr->cb_max_size && len > bin_attr->cb_max_size) {
retval = -EFBIG;
goto out;
}
buffer->bin_buffer = vmalloc(len);
if (buffer->bin_buffer == NULL) {
retval = -ENOMEM;
goto out;
}
buffer->bin_buffer_size = len;
/* perform second read to fill buffer */
len = bin_attr->read(item, buffer->bin_buffer, len);
if (len < 0) {
retval = len;
vfree(buffer->bin_buffer);
buffer->bin_buffer_size = 0;
buffer->bin_buffer = NULL;
goto out;
}
buffer->needs_read_fill = 0;
}
retval = simple_read_from_buffer(buf, count, ppos, buffer->bin_buffer,
buffer->bin_buffer_size);
out:
mutex_unlock(&buffer->mutex);
return retval;
}
static ssize_t
configfs_write_bin_file(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
struct configfs_buffer *buffer = file->private_data;
struct dentry *dentry = file->f_path.dentry;
struct configfs_bin_attribute *bin_attr = to_bin_attr(dentry);
void *tbuf = NULL;
ssize_t len;
mutex_lock(&buffer->mutex);
/* we don't support switching read/write modes */
if (buffer->read_in_progress) {
len = -ETXTBSY;
goto out;
}
buffer->write_in_progress = 1;
/* buffer grows? */
if (*ppos + count > buffer->bin_buffer_size) {
if (bin_attr->cb_max_size &&
*ppos + count > bin_attr->cb_max_size) {
len = -EFBIG;
}
tbuf = vmalloc(*ppos + count);
if (tbuf == NULL) {
len = -ENOMEM;
goto out;
}
/* copy old contents */
if (buffer->bin_buffer) {
memcpy(tbuf, buffer->bin_buffer,
buffer->bin_buffer_size);
vfree(buffer->bin_buffer);
}
/* clear the new area */
memset(tbuf + buffer->bin_buffer_size, 0,
*ppos + count - buffer->bin_buffer_size);
buffer->bin_buffer = tbuf;
buffer->bin_buffer_size = *ppos + count;
}
len = simple_write_to_buffer(buffer->bin_buffer,
buffer->bin_buffer_size, ppos, buf, count);
if (len > 0)
*ppos += len;
out:
mutex_unlock(&buffer->mutex);
return len;
}
static int
flush_write(struct dentry *dentry, char *buffer, loff_t offset, size_t count)
{
struct bin_attribute *attr = to_bin_attr(dentry);
struct kobject *kobj = to_kobj(dentry->d_parent);
if (!attr->write)
return -EIO;
return attr->write(kobj, buffer, offset, count);
}
static int
fill_read(struct dentry *dentry, char *buffer, loff_t off, size_t count)
{
struct bin_attribute * attr = to_bin_attr(dentry);
struct kobject * kobj = to_kobj(dentry->d_parent);
if (!attr->read)
return -EIO;
return attr->read(kobj, buffer, off, count);
}
static int mmap(struct file *file, struct vm_area_struct *vma)
{
struct dentry *dentry = file->f_dentry;
struct bin_attribute *attr = to_bin_attr(dentry);
struct kobject *kobj = to_kobj(dentry->d_parent);
if (!attr->mmap)
return -EINVAL;
return attr->mmap(kobj, attr, vma);
}
static int release(struct inode * inode, struct file * file)
{
struct kobject * kobj = to_kobj(file->f_dentry->d_parent);
struct bin_attribute * attr = to_bin_attr(file->f_dentry);
u8 * buffer = file->private_data;
if (kobj)
kobject_put(kobj);
module_put(attr->attr.owner);
kfree(buffer);
return 0;
}
static int check_perm(struct inode * inode, struct file * file, int type)
{
struct config_item *item = configfs_get_config_item(file->f_path.dentry->d_parent);
struct configfs_attribute * attr = to_attr(file->f_path.dentry);
struct configfs_bin_attribute *bin_attr = NULL;
struct configfs_buffer * buffer;
struct configfs_item_operations * ops = NULL;
int error = 0;
if (!item || !attr)
goto Einval;
if (type & CONFIGFS_ITEM_BIN_ATTR)
bin_attr = to_bin_attr(file->f_path.dentry);
/* Grab the module reference for this attribute if we have one */
if (!try_module_get(attr->ca_owner)) {
error = -ENODEV;
goto Done;
}
if (item->ci_type)
ops = item->ci_type->ct_item_ops;
else
goto Eaccess;
/* File needs write support.
* The inode's perms must say it's ok,
* and we must have a store method.
*/
if (file->f_mode & FMODE_WRITE) {
if (!(inode->i_mode & S_IWUGO))
goto Eaccess;
if ((type & CONFIGFS_ITEM_ATTR) && !attr->store)
goto Eaccess;
if ((type & CONFIGFS_ITEM_BIN_ATTR) && !bin_attr->write)
goto Eaccess;
}
/* File needs read support.
* The inode's perms must say it's ok, and we there
* must be a show method for it.
*/
if (file->f_mode & FMODE_READ) {
if (!(inode->i_mode & S_IRUGO))
goto Eaccess;
if ((type & CONFIGFS_ITEM_ATTR) && !attr->show)
goto Eaccess;
if ((type & CONFIGFS_ITEM_BIN_ATTR) && !bin_attr->read)
goto Eaccess;
}
/* No error? Great, allocate a buffer for the file, and store it
* it in file->private_data for easy access.
*/
buffer = kzalloc(sizeof(struct configfs_buffer),GFP_KERNEL);
if (!buffer) {
error = -ENOMEM;
goto Enomem;
}
mutex_init(&buffer->mutex);
buffer->needs_read_fill = 1;
buffer->read_in_progress = 0;
buffer->write_in_progress = 0;
buffer->ops = ops;
file->private_data = buffer;
goto Done;
Einval:
error = -EINVAL;
goto Done;
Eaccess:
error = -EACCES;
Enomem:
module_put(attr->ca_owner);
Done:
if (error && item)
config_item_put(item);
return error;
}