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/*
File: fs/xattr.c
Extended attribute handling.
Copyright (C) 2001 by Andreas Gruenbacher <a.gruenbacher@computer.org>
Copyright (C) 2001 SGI - Silicon Graphics, Inc <linux-xfs@oss.sgi.com>
*/
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/smp_lock.h>
#include <linux/file.h>
#include <linux/xattr.h>
#include <asm/uaccess.h>
/*
* Extended attribute memory allocation wrappers, originally
* based on the Intermezzo PRESTO_ALLOC/PRESTO_FREE macros.
* The vmalloc use here is very uncommon - extended attributes
* are supposed to be small chunks of metadata, and it is quite
* unusual to have very many extended attributes, so lists tend
* to be quite short as well. The 64K upper limit is derived
* from the extended attribute size limit used by XFS.
* Intentionally allow zero @size for value/list size requests.
*/
static void *
xattr_alloc(size_t size, size_t limit)
{
void *ptr;
if (size > limit)
return ERR_PTR(-E2BIG);
if (!size) /* size request, no buffer is needed */
return NULL;
else if (size <= PAGE_SIZE)
ptr = kmalloc((unsigned long) size, GFP_KERNEL);
else
ptr = vmalloc((unsigned long) size);
if (!ptr)
return ERR_PTR(-ENOMEM);
return ptr;
}
static void
xattr_free(void *ptr, size_t size)
{
if (!size) /* size request, no buffer was needed */
return;
else if (size <= PAGE_SIZE)
kfree(ptr);
else
vfree(ptr);
}
/*
* Extended attribute SET operations
*/
static long
setxattr(struct dentry *d, char *name, void *value, size_t size, int flags)
{
int error;
void *kvalue;
char kname[XATTR_NAME_MAX + 1];
if (flags & ~(XATTR_CREATE|XATTR_REPLACE))
return -EINVAL;
error = strncpy_from_user(kname, name, sizeof(kname));
if (error == 0 || error == sizeof(kname))
error = -ERANGE;
if (error < 0)
return error;
kvalue = xattr_alloc(size, XATTR_SIZE_MAX);
if (IS_ERR(kvalue))
return PTR_ERR(kvalue);
if (size > 0 && copy_from_user(kvalue, value, size)) {
xattr_free(kvalue, size);
return -EFAULT;
}
error = -EOPNOTSUPP;
if (d->d_inode->i_op && d->d_inode->i_op->setxattr) {
lock_kernel();
error = d->d_inode->i_op->setxattr(d, kname, kvalue, size, flags);
unlock_kernel();
}
xattr_free(kvalue, size);
return error;
}
asmlinkage long
sys_setxattr(char *path, char *name, void *value, size_t size, int flags)
{
struct nameidata nd;
int error;
error = user_path_walk(path, &nd);
if (error)
return error;
error = setxattr(nd.dentry, name, value, size, flags);
path_release(&nd);
return error;
}
asmlinkage long
sys_lsetxattr(char *path, char *name, void *value, size_t size, int flags)
{
struct nameidata nd;
int error;
error = user_path_walk_link(path, &nd);
if (error)
return error;
error = setxattr(nd.dentry, name, value, size, flags);
path_release(&nd);
return error;
}
asmlinkage long
sys_fsetxattr(int fd, char *name, void *value, size_t size, int flags)
{
struct file *f;
int error = -EBADF;
f = fget(fd);
if (!f)
return error;
error = setxattr(f->f_dentry, name, value, size, flags);
fput(f);
return error;
}
/*
* Extended attribute GET operations
*/
static ssize_t
getxattr(struct dentry *d, char *name, void *value, size_t size)
{
ssize_t error;
void *kvalue;
char kname[XATTR_NAME_MAX + 1];
error = strncpy_from_user(kname, name, sizeof(kname));
if (error == 0 || error == sizeof(kname))
error = -ERANGE;
if (error < 0)
return error;
kvalue = xattr_alloc(size, XATTR_SIZE_MAX);
if (IS_ERR(kvalue))
return PTR_ERR(kvalue);
error = -EOPNOTSUPP;
if (d->d_inode->i_op && d->d_inode->i_op->getxattr) {
lock_kernel();
error = d->d_inode->i_op->getxattr(d, kname, kvalue, size);
unlock_kernel();
}
if (kvalue && error > 0)
if (copy_to_user(value, kvalue, error))
error = -EFAULT;
xattr_free(kvalue, size);
return error;
}
asmlinkage ssize_t
sys_getxattr(char *path, char *name, void *value, size_t size)
{
struct nameidata nd;
ssize_t error;
error = user_path_walk(path, &nd);
if (error)
return error;
error = getxattr(nd.dentry, name, value, size);
path_release(&nd);
return error;
}
asmlinkage ssize_t
sys_lgetxattr(char *path, char *name, void *value, size_t size)
{
struct nameidata nd;
ssize_t error;
error = user_path_walk_link(path, &nd);
if (error)
return error;
error = getxattr(nd.dentry, name, value, size);
path_release(&nd);
return error;
}
asmlinkage ssize_t
sys_fgetxattr(int fd, char *name, void *value, size_t size)
{
struct file *f;
ssize_t error = -EBADF;
f = fget(fd);
if (!f)
return error;
error = getxattr(f->f_dentry, name, value, size);
fput(f);
return error;
}
/*
* Extended attribute LIST operations
*/
static ssize_t
listxattr(struct dentry *d, char *list, size_t size)
{
ssize_t error;
char *klist;
klist = (char *)xattr_alloc(size, XATTR_LIST_MAX);
if (IS_ERR(klist))
return PTR_ERR(klist);
error = -EOPNOTSUPP;
if (d->d_inode->i_op && d->d_inode->i_op->listxattr) {
lock_kernel();
error = d->d_inode->i_op->listxattr(d, klist, size);
unlock_kernel();
}
if (klist && error > 0)
if (copy_to_user(list, klist, error))
error = -EFAULT;
xattr_free(klist, size);
return error;
}
asmlinkage ssize_t
sys_listxattr(char *path, char *list, size_t size)
{
struct nameidata nd;
ssize_t error;
error = user_path_walk(path, &nd);
if (error)
return error;
error = listxattr(nd.dentry, list, size);
path_release(&nd);
return error;
}
asmlinkage ssize_t
sys_llistxattr(char *path, char *list, size_t size)
{
struct nameidata nd;
ssize_t error;
error = user_path_walk_link(path, &nd);
if (error)
return error;
error = listxattr(nd.dentry, list, size);
path_release(&nd);
return error;
}
asmlinkage ssize_t
sys_flistxattr(int fd, char *list, size_t size)
{
struct file *f;
ssize_t error = -EBADF;
f = fget(fd);
if (!f)
return error;
error = listxattr(f->f_dentry, list, size);
fput(f);
return error;
}
/*
* Extended attribute REMOVE operations
*/
static long
removexattr(struct dentry *d, char *name)
{
int error;
char kname[XATTR_NAME_MAX + 1];
error = strncpy_from_user(kname, name, sizeof(kname));
if (error == 0 || error == sizeof(kname))
error = -ERANGE;
if (error < 0)
return error;
error = -EOPNOTSUPP;
if (d->d_inode->i_op && d->d_inode->i_op->removexattr) {
lock_kernel();
error = d->d_inode->i_op->removexattr(d, kname);
unlock_kernel();
}
return error;
}
asmlinkage long
sys_removexattr(char *path, char *name)
{
struct nameidata nd;
int error;
error = user_path_walk(path, &nd);
if (error)
return error;
error = removexattr(nd.dentry, name);
path_release(&nd);
return error;
}
asmlinkage long
sys_lremovexattr(char *path, char *name)
{
struct nameidata nd;
int error;
error = user_path_walk_link(path, &nd);
if (error)
return error;
error = removexattr(nd.dentry, name);
path_release(&nd);
return error;
}
asmlinkage long
sys_fremovexattr(int fd, char *name)
{
struct file *f;
int error = -EBADF;
f = fget(fd);
if (!f)
return error;
error = removexattr(f->f_dentry, name);
fput(f);
return error;
}
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