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/*
* 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;
};
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 = to_kobj(dentry->d_parent);
if (!attr->read)
return -EIO;
return attr->read(kobj, buffer, off, count);
}
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 = to_kobj(dentry->d_parent);
if (!attr->write)
return -EIO;
return attr->write(kobj, buffer, offset, count);
}
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 = to_kobj(file->f_path.dentry->d_parent);
int rc;
if (!attr->mmap)
return -EINVAL;
mutex_lock(&bb->mutex);
rc = attr->mmap(kobj, attr, vma);
mutex_unlock(&bb->mutex);
return rc;
}
static int open(struct inode * inode, struct file * file)
{
struct kobject *kobj = sysfs_get_kobject(file->f_path.dentry->d_parent);
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 = -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;
bb = kzalloc(sizeof(*bb), GFP_KERNEL);
if (!bb)
goto Error;
bb->buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!bb->buffer)
goto Error;
mutex_init(&bb->mutex);
file->private_data = bb;
error = 0;
goto Done;
Error:
kfree(bb);
module_put(attr->attr.owner);
Done:
if (error)
kobject_put(kobj);
return error;
}
static int release(struct inode * inode, struct file * file)
{
struct kobject * kobj = to_kobj(file->f_path.dentry->d_parent);
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 = file->private_data;
kobject_put(kobj);
module_put(attr->attr.owner);
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->dentry || !attr);
return sysfs_add_file(kobj->dentry, &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->dentry, 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);
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