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/*

 * fs/sysfs/bin.c - sysfs binary file implementation

 *

 * Copyright (c) 2003 Patrick Mochel

 * Copyright (c) 2003 Matthew Wilcox

 * Copyright (c) 2004 Silicon Graphics, Inc.

 * Copyright (c) 2007 SUSE Linux Products GmbH

 * Copyright (c) 2007 Tejun Heo <teheo@suse.de>

 *

 * This file is released under the GPLv2.

 *

 * Please see Documentation/filesystems/sysfs.txt for more information.

 */

#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 <linux/mutex.h>

#include <asm/uaccess.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_bin_attr.bin_attr;

        struct kobject *kobj = attr_sd->s_parent->s_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_bin_attr.bin_attr;

        struct kobject *kobj = attr_sd->s_parent->s_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_bin_attr.bin_attr;

        struct kobject *kobj = attr_sd->s_parent->s_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_bin_attr.bin_attr;

        struct bin_buffer *bb = NULL;

        int error;

        /* binary file operations requires both @sd and its parent */

        if (!sysfs_get_active_two(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 references */

        sysfs_put_active_two(attr_sd);

        return 0;

 err_out:

        sysfs_put_active_two(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);

        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)

{

        sysfs_hash_and_remove(kobj->sd, attr->attr.name);

}

EXPORT_SYMBOL_GPL(sysfs_create_bin_file);

EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);