/* * bin.c - binary file operations for sysfs. */ #include <linux/errno.h> #include <linux/fs.h> #include <linux/kobject.h> #include <linux/module.h> #include <linux/slab.h> #include <asm/uaccess.h> #include "sysfs.h" static int fill_read(struct dentry *dentry, char *buffer, loff_t off, size_t count) { struct bin_attribute * attr = dentry->d_fsdata; struct kobject * kobj = dentry->d_parent->d_fsdata; return attr->read(kobj, buffer, off, count); } static ssize_t read(struct file * file, char * userbuf, size_t count, loff_t * off) { char *buffer = file->private_data; struct dentry *dentry = file->f_dentry; int size = dentry->d_inode->i_size; loff_t offs = *off; int ret; if (count > PAGE_SIZE) count = PAGE_SIZE; if (size) { if (offs > size) return 0; if (offs + count > size) count = size - offs; } ret = fill_read(dentry, buffer, offs, count); if (ret < 0) goto Done; count = ret; ret = -EFAULT; if (copy_to_user(userbuf, buffer, count) != 0) goto Done; *off = offs + count; ret = count; Done: return ret; } static int flush_write(struct dentry *dentry, char *buffer, loff_t offset, size_t count) { struct bin_attribute *attr = dentry->d_fsdata; struct kobject *kobj = dentry->d_parent->d_fsdata; return attr->write(kobj, buffer, offset, count); } static ssize_t write(struct file * file, const char * userbuf, size_t count, loff_t * off) { char *buffer = file->private_data; struct dentry *dentry = file->f_dentry; int size = dentry->d_inode->i_size; loff_t offs = *off; int ret; if (count > PAGE_SIZE) count = PAGE_SIZE; if (size) { if (offs > size) return 0; if (offs + count > size) count = size - offs; } ret = -EFAULT; if (copy_from_user(buffer, userbuf, count)) goto Done; count = flush_write(dentry, buffer, offs, count); if (count > 0) *off = offs + count; ret = count; Done: return ret; } static int open(struct inode * inode, struct file * file) { struct kobject * kobj = kobject_get(file->f_dentry->d_parent->d_fsdata); struct bin_attribute * attr = file->f_dentry->d_fsdata; int error = -EINVAL; if (!kobj || !attr) goto Done; error = -EACCES; if ((file->f_mode & FMODE_WRITE) && !attr->write) goto Done; if ((file->f_mode & FMODE_READ) && !attr->read) goto Done; error = -ENOMEM; file->private_data = kmalloc(PAGE_SIZE, GFP_KERNEL); if (!file->private_data) goto Done; error = 0; Done: if (error && kobj) kobject_put(kobj); return error; } static int release(struct inode * inode, struct file * file) { struct kobject * kobj = file->f_dentry->d_parent->d_fsdata; u8 * buffer = file->private_data; if (kobj) kobject_put(kobj); kfree(buffer); return 0; } static struct file_operations bin_fops = { .read = read, .write = write, .llseek = generic_file_llseek, .open = open, .release = release, }; /** * sysfs_create_bin_file - create binary file for object. * @kobj: object. * @attr: attribute descriptor. * */ int sysfs_create_bin_file(struct kobject * kobj, struct bin_attribute * attr) { struct dentry * dentry; struct dentry * parent; int error = 0; if (!kobj || !attr) return -EINVAL; parent = kobj->dentry; down(&parent->d_inode->i_sem); dentry = sysfs_get_dentry(parent,attr->attr.name); if (!IS_ERR(dentry)) { dentry->d_fsdata = (void *)attr; error = sysfs_create(dentry, (attr->attr.mode & S_IALLUGO) | S_IFREG, NULL); if (!error) { dentry->d_inode->i_size = attr->size; dentry->d_inode->i_fop = &bin_fops; } } else error = PTR_ERR(dentry); up(&parent->d_inode->i_sem); return error; } /** * sysfs_remove_bin_file - remove binary file for object. * @kobj: object. * @attr: attribute descriptor. * */ int sysfs_remove_bin_file(struct kobject * kobj, struct bin_attribute * attr) { sysfs_hash_and_remove(kobj->dentry,attr->attr.name); return 0; } EXPORT_SYMBOL(sysfs_create_bin_file); EXPORT_SYMBOL(sysfs_remove_bin_file);