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 sysfs_getlink(struct dentry *dentry, char * path)
{
struct kobject *kobj, *target_kobj;
int error = 0;
kobj = sysfs_get_kobject(dentry->d_parent);
if (!kobj)
return -EINVAL;
target_kobj = sysfs_get_kobject(dentry);
if (!target_kobj) {
kobject_put(kobj);
return -EINVAL;
}
down_read(&sysfs_rename_sem);
error = sysfs_get_target_path(kobj, target_kobj, path);
up_read(&sysfs_rename_sem);
kobject_put(kobj);
kobject_put(target_kobj);
return error;
}
static int check_perm(struct inode * inode, struct file * file)
{
struct kobject *kobj = sysfs_get_kobject(file->f_dentry->d_parent);
struct attribute * attr = file->f_dentry->d_fsdata;
struct sysfs_buffer * buffer;
struct sysfs_ops * ops = NULL;
int error = 0;
if (!kobj || !attr)
goto Einval;
/* Grab the module reference for this attribute if we have one */
if (!try_module_get(attr->owner)) {
error = -ENODEV;
goto Done;
}
/* if the kobject has no ktype, then we assume that it is a subsystem
* itself, and use ops for it.
*/
if (kobj->kset && kobj->kset->ktype)
ops = kobj->kset->ktype->sysfs_ops;
else if (kobj->ktype)
ops = kobj->ktype->sysfs_ops;
else
ops = &subsys_sysfs_ops;
/* No sysfs operations, either from having no subsystem,
* or the subsystem have no operations.
*/
if (!ops)
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) || !ops->store)
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) || !ops->show)
goto Eaccess;
}
/* No error? Great, allocate a buffer for the file, and store it
* it in file->private_data for easy access.
*/
buffer = kmalloc(sizeof(struct sysfs_buffer),GFP_KERNEL);
if (buffer) {
memset(buffer,0,sizeof(struct sysfs_buffer));
buffer->ops = ops;
file->private_data = buffer;
} else
error = -ENOMEM;
goto Done;
Einval:
error = -EINVAL;
goto Done;
Eaccess:
error = -EACCES;
module_put(attr->owner);
Done:
if (error && kobj)
kobject_put(kobj);
return error;
}
