/* * bin.c - binary file operations for sysfs. * * Copyright (c) 2003 Patrick Mochel * Copyright (c) 2003 Matthew Wilcox * Copyright (c) 2004 Silicon Graphics, Inc. */ #undef DEBUG #include <linux/errno.h> #include <linux/fs.h> #include <linux/kernel.h> #include <linux/kobject.h> #include <linux/module.h> #include <linux/slab.h> #include <asm/uaccess.h> #include <asm/semaphore.h> #include "sysfs.h" struct bin_buffer { struct mutex mutex; void *buffer; int mmapped; }; static int fill_read(struct dentry *dentry, char *buffer, loff_t off, size_t count) { struct sysfs_dirent *attr_sd = dentry->d_fsdata; struct bin_attribute *attr = attr_sd->s_elem.bin_attr.bin_attr; struct kobject *kobj = attr_sd->s_parent->s_elem.dir.kobj; int rc; /* need attr_sd for attr, its parent for kobj */ if (!sysfs_get_active_two(attr_sd)) return -ENODEV; rc = -EIO; if (attr->read) rc = attr->read(kobj, attr, buffer, off, count); sysfs_put_active_two(attr_sd); return rc; } static ssize_t read(struct file *file, char __user *userbuf, size_t bytes, loff_t *off) { struct bin_buffer *bb = file->private_data; struct dentry *dentry = file->f_path.dentry; int size = dentry->d_inode->i_size; loff_t offs = *off; int count = min_t(size_t, bytes, PAGE_SIZE); if (size) { if (offs > size) return 0; if (offs + count > size) count = size - offs; } mutex_lock(&bb->mutex); count = fill_read(dentry, bb->buffer, offs, count); if (count < 0) goto out_unlock; if (copy_to_user(userbuf, bb->buffer, count)) { count = -EFAULT; goto out_unlock; } pr_debug("offs = %lld, *off = %lld, count = %d\n", offs, *off, count); *off = offs + count; out_unlock: mutex_unlock(&bb->mutex); return count; } static int flush_write(struct dentry *dentry, char *buffer, loff_t offset, size_t count) { struct sysfs_dirent *attr_sd = dentry->d_fsdata; struct bin_attribute *attr = attr_sd->s_elem.bin_attr.bin_attr; struct kobject *kobj = attr_sd->s_parent->s_elem.dir.kobj; int rc; /* need attr_sd for attr, its parent for kobj */ if (!sysfs_get_active_two(attr_sd)) return -ENODEV; rc = -EIO; if (attr->write) rc = attr->write(kobj, attr, buffer, offset, count); sysfs_put_active_two(attr_sd); return rc; } static ssize_t write(struct file *file, const char __user *userbuf, size_t bytes, loff_t *off) { struct bin_buffer *bb = file->private_data; struct dentry *dentry = file->f_path.dentry; int size = dentry->d_inode->i_size; loff_t offs = *off; int count = min_t(size_t, bytes, PAGE_SIZE); if (size) { if (offs > size) return 0; if (offs + count > size) count = size - offs; } mutex_lock(&bb->mutex); if (copy_from_user(bb->buffer, userbuf, count)) { count = -EFAULT; goto out_unlock; } count = flush_write(dentry, bb->buffer, offs, count); if (count > 0) *off = offs + count; out_unlock: mutex_unlock(&bb->mutex); return count; } static int mmap(struct file *file, struct vm_area_struct *vma) { struct bin_buffer *bb = file->private_data; struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; struct bin_attribute *attr = attr_sd->s_elem.bin_attr.bin_attr; struct kobject *kobj = attr_sd->s_parent->s_elem.dir.kobj; int rc; mutex_lock(&bb->mutex); /* need attr_sd for attr, its parent for kobj */ if (!sysfs_get_active_two(attr_sd)) return -ENODEV; rc = -EINVAL; if (attr->mmap) rc = attr->mmap(kobj, attr, vma); if (rc == 0 && !bb->mmapped) bb->mmapped = 1; else sysfs_put_active_two(attr_sd); mutex_unlock(&bb->mutex); return rc; } static int open(struct inode * inode, struct file * file) { struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; struct bin_attribute *attr = attr_sd->s_elem.bin_attr.bin_attr; struct bin_buffer *bb = NULL; int error; /* need attr_sd for attr */ if (!sysfs_get_active(attr_sd)) return -ENODEV; error = -EACCES; if ((file->f_mode & FMODE_WRITE) && !(attr->write || attr->mmap)) goto err_out; if ((file->f_mode & FMODE_READ) && !(attr->read || attr->mmap)) goto err_out; error = -ENOMEM; bb = kzalloc(sizeof(*bb), GFP_KERNEL); if (!bb) goto err_out; bb->buffer = kmalloc(PAGE_SIZE, GFP_KERNEL); if (!bb->buffer) goto err_out; mutex_init(&bb->mutex); file->private_data = bb; /* open succeeded, put active reference and pin attr_sd */ sysfs_put_active(attr_sd); sysfs_get(attr_sd); return 0; err_out: sysfs_put_active(attr_sd); kfree(bb); return error; } static int release(struct inode * inode, struct file * file) { struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; struct bin_buffer *bb = file->private_data; if (bb->mmapped) sysfs_put_active_two(attr_sd); sysfs_put(attr_sd); kfree(bb->buffer); kfree(bb); return 0; } const struct file_operations bin_fops = { .read = read, .write = write, .mmap = mmap, .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) { BUG_ON(!kobj || !kobj->sd || !attr); return sysfs_add_file(kobj->sd, &attr->attr, SYSFS_KOBJ_BIN_ATTR); } /** * sysfs_remove_bin_file - remove binary file for object. * @kobj: object. * @attr: attribute descriptor. */ void sysfs_remove_bin_file(struct kobject * kobj, struct bin_attribute * attr) { if (sysfs_hash_and_remove(kobj->sd, attr->attr.name) < 0) { printk(KERN_ERR "%s: " "bad dentry or inode or no such file: \"%s\"\n", __FUNCTION__, attr->attr.name); dump_stack(); } } EXPORT_SYMBOL_GPL(sysfs_create_bin_file); EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);