linux/fs/sysfs/bin.c
Eric W. Biederman 38f49a5132 sysfs: only access bin file vm_ops with the active lock
bb->vm_ops is a cached copy of the vm_ops of the underlying
sysfs bin file, which means that after sysfs_bin_remove_file
completes it is only longer valid to deference bb->vm_ops.

So move all of the tests of bb->vm_ops inside of where
we hold the sysfs active lock.

Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-10-22 10:16:43 -07:00

507 lines
11 KiB
C

/*
* 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 <linux/mm.h>
#include <asm/uaccess.h>
#include "sysfs.h"
/*
* There's one bin_buffer for each open file.
*
* filp->private_data points to bin_buffer and
* sysfs_dirent->s_bin_attr.buffers points to a the bin_buffer s
* sysfs_dirent->s_bin_attr.buffers is protected by sysfs_bin_lock
*/
static DEFINE_MUTEX(sysfs_bin_lock);
struct bin_buffer {
struct mutex mutex;
void *buffer;
int mmapped;
const struct vm_operations_struct *vm_ops;
struct file *file;
struct hlist_node list;
};
static int
fill_read(struct file *file, char *buffer, loff_t off, size_t count)
{
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;
/* need attr_sd for attr, its parent for kobj */
if (!sysfs_get_active(attr_sd))
return -ENODEV;
rc = -EIO;
if (attr->read)
rc = attr->read(file, kobj, attr, buffer, off, count);
sysfs_put_active(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;
int size = file->f_path.dentry->d_inode->i_size;
loff_t offs = *off;
int count = min_t(size_t, bytes, PAGE_SIZE);
char *temp;
if (!bytes)
return 0;
if (size) {
if (offs > size)
return 0;
if (offs + count > size)
count = size - offs;
}
temp = kmalloc(count, GFP_KERNEL);
if (!temp)
return -ENOMEM;
mutex_lock(&bb->mutex);
count = fill_read(file, bb->buffer, offs, count);
if (count < 0) {
mutex_unlock(&bb->mutex);
goto out_free;
}
memcpy(temp, bb->buffer, count);
mutex_unlock(&bb->mutex);
if (copy_to_user(userbuf, temp, count)) {
count = -EFAULT;
goto out_free;
}
pr_debug("offs = %lld, *off = %lld, count = %d\n", offs, *off, count);
*off = offs + count;
out_free:
kfree(temp);
return count;
}
static int
flush_write(struct file *file, char *buffer, loff_t offset, size_t count)
{
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;
/* need attr_sd for attr, its parent for kobj */
if (!sysfs_get_active(attr_sd))
return -ENODEV;
rc = -EIO;
if (attr->write)
rc = attr->write(file, kobj, attr, buffer, offset, count);
sysfs_put_active(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;
int size = file->f_path.dentry->d_inode->i_size;
loff_t offs = *off;
int count = min_t(size_t, bytes, PAGE_SIZE);
char *temp;
if (!bytes)
return 0;
if (size) {
if (offs > size)
return 0;
if (offs + count > size)
count = size - offs;
}
temp = memdup_user(userbuf, count);
if (IS_ERR(temp))
return PTR_ERR(temp);
mutex_lock(&bb->mutex);
memcpy(bb->buffer, temp, count);
count = flush_write(file, bb->buffer, offs, count);
mutex_unlock(&bb->mutex);
if (count > 0)
*off = offs + count;
kfree(temp);
return count;
}
static void bin_vma_open(struct vm_area_struct *vma)
{
struct file *file = vma->vm_file;
struct bin_buffer *bb = file->private_data;
struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
if (!bb->vm_ops)
return;
if (!sysfs_get_active(attr_sd))
return;
if (bb->vm_ops->open)
bb->vm_ops->open(vma);
sysfs_put_active(attr_sd);
}
static int bin_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
struct file *file = vma->vm_file;
struct bin_buffer *bb = file->private_data;
struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
int ret;
if (!bb->vm_ops)
return VM_FAULT_SIGBUS;
if (!sysfs_get_active(attr_sd))
return VM_FAULT_SIGBUS;
ret = VM_FAULT_SIGBUS;
if (bb->vm_ops->fault)
ret = bb->vm_ops->fault(vma, vmf);
sysfs_put_active(attr_sd);
return ret;
}
static int bin_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
{
struct file *file = vma->vm_file;
struct bin_buffer *bb = file->private_data;
struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
int ret;
if (!bb->vm_ops)
return VM_FAULT_SIGBUS;
if (!sysfs_get_active(attr_sd))
return VM_FAULT_SIGBUS;
ret = 0;
if (bb->vm_ops->page_mkwrite)
ret = bb->vm_ops->page_mkwrite(vma, vmf);
sysfs_put_active(attr_sd);
return ret;
}
static int bin_access(struct vm_area_struct *vma, unsigned long addr,
void *buf, int len, int write)
{
struct file *file = vma->vm_file;
struct bin_buffer *bb = file->private_data;
struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
int ret;
if (!bb->vm_ops)
return -EINVAL;
if (!sysfs_get_active(attr_sd))
return -EINVAL;
ret = -EINVAL;
if (bb->vm_ops->access)
ret = bb->vm_ops->access(vma, addr, buf, len, write);
sysfs_put_active(attr_sd);
return ret;
}
#ifdef CONFIG_NUMA
static int bin_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
{
struct file *file = vma->vm_file;
struct bin_buffer *bb = file->private_data;
struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
int ret;
if (!bb->vm_ops)
return 0;
if (!sysfs_get_active(attr_sd))
return -EINVAL;
ret = 0;
if (bb->vm_ops->set_policy)
ret = bb->vm_ops->set_policy(vma, new);
sysfs_put_active(attr_sd);
return ret;
}
static struct mempolicy *bin_get_policy(struct vm_area_struct *vma,
unsigned long addr)
{
struct file *file = vma->vm_file;
struct bin_buffer *bb = file->private_data;
struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
struct mempolicy *pol;
if (!bb->vm_ops)
return vma->vm_policy;
if (!sysfs_get_active(attr_sd))
return vma->vm_policy;
pol = vma->vm_policy;
if (bb->vm_ops->get_policy)
pol = bb->vm_ops->get_policy(vma, addr);
sysfs_put_active(attr_sd);
return pol;
}
static int bin_migrate(struct vm_area_struct *vma, const nodemask_t *from,
const nodemask_t *to, unsigned long flags)
{
struct file *file = vma->vm_file;
struct bin_buffer *bb = file->private_data;
struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
int ret;
if (!bb->vm_ops)
return 0;
if (!sysfs_get_active(attr_sd))
return 0;
ret = 0;
if (bb->vm_ops->migrate)
ret = bb->vm_ops->migrate(vma, from, to, flags);
sysfs_put_active(attr_sd);
return ret;
}
#endif
static const struct vm_operations_struct bin_vm_ops = {
.open = bin_vma_open,
.fault = bin_fault,
.page_mkwrite = bin_page_mkwrite,
.access = bin_access,
#ifdef CONFIG_NUMA
.set_policy = bin_set_policy,
.get_policy = bin_get_policy,
.migrate = bin_migrate,
#endif
};
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 */
rc = -ENODEV;
if (!sysfs_get_active(attr_sd))
goto out_unlock;
rc = -EINVAL;
if (!attr->mmap)
goto out_put;
rc = attr->mmap(file, kobj, attr, vma);
if (rc)
goto out_put;
/*
* PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup()
* to satisfy versions of X which crash if the mmap fails: that
* substitutes a new vm_file, and we don't then want bin_vm_ops.
*/
if (vma->vm_file != file)
goto out_put;
rc = -EINVAL;
if (bb->mmapped && bb->vm_ops != vma->vm_ops)
goto out_put;
/*
* It is not possible to successfully wrap close.
* So error if someone is trying to use close.
*/
rc = -EINVAL;
if (vma->vm_ops && vma->vm_ops->close)
goto out_put;
rc = 0;
bb->mmapped = 1;
bb->vm_ops = vma->vm_ops;
vma->vm_ops = &bin_vm_ops;
out_put:
sysfs_put_active(attr_sd);
out_unlock:
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(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);
bb->file = file;
file->private_data = bb;
mutex_lock(&sysfs_bin_lock);
hlist_add_head(&bb->list, &attr_sd->s_bin_attr.buffers);
mutex_unlock(&sysfs_bin_lock);
/* open succeeded, put active references */
sysfs_put_active(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 bin_buffer *bb = file->private_data;
mutex_lock(&sysfs_bin_lock);
hlist_del(&bb->list);
mutex_unlock(&sysfs_bin_lock);
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,
};
void unmap_bin_file(struct sysfs_dirent *attr_sd)
{
struct bin_buffer *bb;
struct hlist_node *tmp;
if (sysfs_type(attr_sd) != SYSFS_KOBJ_BIN_ATTR)
return;
mutex_lock(&sysfs_bin_lock);
hlist_for_each_entry(bb, tmp, &attr_sd->s_bin_attr.buffers, list) {
struct inode *inode = bb->file->f_path.dentry->d_inode;
unmap_mapping_range(inode->i_mapping, 0, 0, 1);
}
mutex_unlock(&sysfs_bin_lock);
}
/**
* sysfs_create_bin_file - create binary file for object.
* @kobj: object.
* @attr: attribute descriptor.
*/
int sysfs_create_bin_file(struct kobject *kobj,
const 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,
const struct bin_attribute *attr)
{
sysfs_hash_and_remove(kobj->sd, NULL, attr->attr.name);
}
EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);