mirror of https://gitee.com/openkylin/linux.git
367 lines
8.4 KiB
C
367 lines
8.4 KiB
C
/*
|
|
* fs/sysfs/inode.c - basic sysfs inode and dentry operations
|
|
*
|
|
* Copyright (c) 2001-3 Patrick Mochel
|
|
* 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/pagemap.h>
|
|
#include <linux/namei.h>
|
|
#include <linux/backing-dev.h>
|
|
#include <linux/capability.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/sysfs.h>
|
|
#include <linux/xattr.h>
|
|
#include <linux/security.h>
|
|
#include "sysfs.h"
|
|
|
|
extern struct super_block * sysfs_sb;
|
|
|
|
static const struct address_space_operations sysfs_aops = {
|
|
.readpage = simple_readpage,
|
|
.write_begin = simple_write_begin,
|
|
.write_end = simple_write_end,
|
|
};
|
|
|
|
static struct backing_dev_info sysfs_backing_dev_info = {
|
|
.name = "sysfs",
|
|
.ra_pages = 0, /* No readahead */
|
|
.capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
|
|
};
|
|
|
|
static const struct inode_operations sysfs_inode_operations ={
|
|
.permission = sysfs_permission,
|
|
.setattr = sysfs_setattr,
|
|
.getattr = sysfs_getattr,
|
|
.setxattr = sysfs_setxattr,
|
|
};
|
|
|
|
int __init sysfs_inode_init(void)
|
|
{
|
|
return bdi_init(&sysfs_backing_dev_info);
|
|
}
|
|
|
|
static struct sysfs_inode_attrs *sysfs_init_inode_attrs(struct sysfs_dirent *sd)
|
|
{
|
|
struct sysfs_inode_attrs *attrs;
|
|
struct iattr *iattrs;
|
|
|
|
attrs = kzalloc(sizeof(struct sysfs_inode_attrs), GFP_KERNEL);
|
|
if (!attrs)
|
|
return NULL;
|
|
iattrs = &attrs->ia_iattr;
|
|
|
|
/* assign default attributes */
|
|
iattrs->ia_mode = sd->s_mode;
|
|
iattrs->ia_uid = 0;
|
|
iattrs->ia_gid = 0;
|
|
iattrs->ia_atime = iattrs->ia_mtime = iattrs->ia_ctime = CURRENT_TIME;
|
|
|
|
return attrs;
|
|
}
|
|
|
|
int sysfs_sd_setattr(struct sysfs_dirent *sd, struct iattr * iattr)
|
|
{
|
|
struct sysfs_inode_attrs *sd_attrs;
|
|
struct iattr *iattrs;
|
|
unsigned int ia_valid = iattr->ia_valid;
|
|
|
|
sd_attrs = sd->s_iattr;
|
|
|
|
if (!sd_attrs) {
|
|
/* setting attributes for the first time, allocate now */
|
|
sd_attrs = sysfs_init_inode_attrs(sd);
|
|
if (!sd_attrs)
|
|
return -ENOMEM;
|
|
sd->s_iattr = sd_attrs;
|
|
}
|
|
/* attributes were changed at least once in past */
|
|
iattrs = &sd_attrs->ia_iattr;
|
|
|
|
if (ia_valid & ATTR_UID)
|
|
iattrs->ia_uid = iattr->ia_uid;
|
|
if (ia_valid & ATTR_GID)
|
|
iattrs->ia_gid = iattr->ia_gid;
|
|
if (ia_valid & ATTR_ATIME)
|
|
iattrs->ia_atime = iattr->ia_atime;
|
|
if (ia_valid & ATTR_MTIME)
|
|
iattrs->ia_mtime = iattr->ia_mtime;
|
|
if (ia_valid & ATTR_CTIME)
|
|
iattrs->ia_ctime = iattr->ia_ctime;
|
|
if (ia_valid & ATTR_MODE) {
|
|
umode_t mode = iattr->ia_mode;
|
|
iattrs->ia_mode = sd->s_mode = mode;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int sysfs_setattr(struct dentry *dentry, struct iattr *iattr)
|
|
{
|
|
struct inode *inode = dentry->d_inode;
|
|
struct sysfs_dirent *sd = dentry->d_fsdata;
|
|
int error;
|
|
|
|
if (!sd)
|
|
return -EINVAL;
|
|
|
|
mutex_lock(&sysfs_mutex);
|
|
error = inode_change_ok(inode, iattr);
|
|
if (error)
|
|
goto out;
|
|
|
|
error = sysfs_sd_setattr(sd, iattr);
|
|
if (error)
|
|
goto out;
|
|
|
|
/* this ignores size changes */
|
|
setattr_copy(inode, iattr);
|
|
|
|
out:
|
|
mutex_unlock(&sysfs_mutex);
|
|
return error;
|
|
}
|
|
|
|
static int sysfs_sd_setsecdata(struct sysfs_dirent *sd, void **secdata, u32 *secdata_len)
|
|
{
|
|
struct sysfs_inode_attrs *iattrs;
|
|
void *old_secdata;
|
|
size_t old_secdata_len;
|
|
|
|
iattrs = sd->s_iattr;
|
|
if (!iattrs)
|
|
iattrs = sysfs_init_inode_attrs(sd);
|
|
if (!iattrs)
|
|
return -ENOMEM;
|
|
|
|
old_secdata = iattrs->ia_secdata;
|
|
old_secdata_len = iattrs->ia_secdata_len;
|
|
|
|
iattrs->ia_secdata = *secdata;
|
|
iattrs->ia_secdata_len = *secdata_len;
|
|
|
|
*secdata = old_secdata;
|
|
*secdata_len = old_secdata_len;
|
|
return 0;
|
|
}
|
|
|
|
int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value,
|
|
size_t size, int flags)
|
|
{
|
|
struct sysfs_dirent *sd = dentry->d_fsdata;
|
|
void *secdata;
|
|
int error;
|
|
u32 secdata_len = 0;
|
|
|
|
if (!sd)
|
|
return -EINVAL;
|
|
|
|
if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN)) {
|
|
const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
|
|
error = security_inode_setsecurity(dentry->d_inode, suffix,
|
|
value, size, flags);
|
|
if (error)
|
|
goto out;
|
|
error = security_inode_getsecctx(dentry->d_inode,
|
|
&secdata, &secdata_len);
|
|
if (error)
|
|
goto out;
|
|
|
|
mutex_lock(&sysfs_mutex);
|
|
error = sysfs_sd_setsecdata(sd, &secdata, &secdata_len);
|
|
mutex_unlock(&sysfs_mutex);
|
|
|
|
if (secdata)
|
|
security_release_secctx(secdata, secdata_len);
|
|
} else
|
|
return -EINVAL;
|
|
out:
|
|
return error;
|
|
}
|
|
|
|
static inline void set_default_inode_attr(struct inode * inode, mode_t mode)
|
|
{
|
|
inode->i_mode = mode;
|
|
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
|
|
}
|
|
|
|
static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
|
|
{
|
|
inode->i_uid = iattr->ia_uid;
|
|
inode->i_gid = iattr->ia_gid;
|
|
inode->i_atime = iattr->ia_atime;
|
|
inode->i_mtime = iattr->ia_mtime;
|
|
inode->i_ctime = iattr->ia_ctime;
|
|
}
|
|
|
|
static int sysfs_count_nlink(struct sysfs_dirent *sd)
|
|
{
|
|
struct sysfs_dirent *child;
|
|
int nr = 0;
|
|
|
|
for (child = sd->s_dir.children; child; child = child->s_sibling)
|
|
if (sysfs_type(child) == SYSFS_DIR)
|
|
nr++;
|
|
|
|
return nr + 2;
|
|
}
|
|
|
|
static void sysfs_refresh_inode(struct sysfs_dirent *sd, struct inode *inode)
|
|
{
|
|
struct sysfs_inode_attrs *iattrs = sd->s_iattr;
|
|
|
|
inode->i_mode = sd->s_mode;
|
|
if (iattrs) {
|
|
/* sysfs_dirent has non-default attributes
|
|
* get them from persistent copy in sysfs_dirent
|
|
*/
|
|
set_inode_attr(inode, &iattrs->ia_iattr);
|
|
security_inode_notifysecctx(inode,
|
|
iattrs->ia_secdata,
|
|
iattrs->ia_secdata_len);
|
|
}
|
|
|
|
if (sysfs_type(sd) == SYSFS_DIR)
|
|
inode->i_nlink = sysfs_count_nlink(sd);
|
|
}
|
|
|
|
int sysfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
|
|
{
|
|
struct sysfs_dirent *sd = dentry->d_fsdata;
|
|
struct inode *inode = dentry->d_inode;
|
|
|
|
mutex_lock(&sysfs_mutex);
|
|
sysfs_refresh_inode(sd, inode);
|
|
mutex_unlock(&sysfs_mutex);
|
|
|
|
generic_fillattr(inode, stat);
|
|
return 0;
|
|
}
|
|
|
|
static void sysfs_init_inode(struct sysfs_dirent *sd, struct inode *inode)
|
|
{
|
|
struct bin_attribute *bin_attr;
|
|
|
|
inode->i_private = sysfs_get(sd);
|
|
inode->i_mapping->a_ops = &sysfs_aops;
|
|
inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info;
|
|
inode->i_op = &sysfs_inode_operations;
|
|
|
|
set_default_inode_attr(inode, sd->s_mode);
|
|
sysfs_refresh_inode(sd, inode);
|
|
|
|
/* initialize inode according to type */
|
|
switch (sysfs_type(sd)) {
|
|
case SYSFS_DIR:
|
|
inode->i_op = &sysfs_dir_inode_operations;
|
|
inode->i_fop = &sysfs_dir_operations;
|
|
break;
|
|
case SYSFS_KOBJ_ATTR:
|
|
inode->i_size = PAGE_SIZE;
|
|
inode->i_fop = &sysfs_file_operations;
|
|
break;
|
|
case SYSFS_KOBJ_BIN_ATTR:
|
|
bin_attr = sd->s_bin_attr.bin_attr;
|
|
inode->i_size = bin_attr->size;
|
|
inode->i_fop = &bin_fops;
|
|
break;
|
|
case SYSFS_KOBJ_LINK:
|
|
inode->i_op = &sysfs_symlink_inode_operations;
|
|
break;
|
|
default:
|
|
BUG();
|
|
}
|
|
|
|
unlock_new_inode(inode);
|
|
}
|
|
|
|
/**
|
|
* sysfs_get_inode - get inode for sysfs_dirent
|
|
* @sb: super block
|
|
* @sd: sysfs_dirent to allocate inode for
|
|
*
|
|
* Get inode for @sd. If such inode doesn't exist, a new inode
|
|
* is allocated and basics are initialized. New inode is
|
|
* returned locked.
|
|
*
|
|
* LOCKING:
|
|
* Kernel thread context (may sleep).
|
|
*
|
|
* RETURNS:
|
|
* Pointer to allocated inode on success, NULL on failure.
|
|
*/
|
|
struct inode * sysfs_get_inode(struct super_block *sb, struct sysfs_dirent *sd)
|
|
{
|
|
struct inode *inode;
|
|
|
|
inode = iget_locked(sb, sd->s_ino);
|
|
if (inode && (inode->i_state & I_NEW))
|
|
sysfs_init_inode(sd, inode);
|
|
|
|
return inode;
|
|
}
|
|
|
|
/*
|
|
* The sysfs_dirent serves as both an inode and a directory entry for sysfs.
|
|
* To prevent the sysfs inode numbers from being freed prematurely we take a
|
|
* reference to sysfs_dirent from the sysfs inode. A
|
|
* super_operations.evict_inode() implementation is needed to drop that
|
|
* reference upon inode destruction.
|
|
*/
|
|
void sysfs_evict_inode(struct inode *inode)
|
|
{
|
|
struct sysfs_dirent *sd = inode->i_private;
|
|
|
|
truncate_inode_pages(&inode->i_data, 0);
|
|
end_writeback(inode);
|
|
sysfs_put(sd);
|
|
}
|
|
|
|
int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const void *ns, const char *name)
|
|
{
|
|
struct sysfs_addrm_cxt acxt;
|
|
struct sysfs_dirent *sd;
|
|
|
|
if (!dir_sd)
|
|
return -ENOENT;
|
|
|
|
sysfs_addrm_start(&acxt, dir_sd);
|
|
|
|
sd = sysfs_find_dirent(dir_sd, ns, name);
|
|
if (sd && (sd->s_ns != ns))
|
|
sd = NULL;
|
|
if (sd)
|
|
sysfs_remove_one(&acxt, sd);
|
|
|
|
sysfs_addrm_finish(&acxt);
|
|
|
|
if (sd)
|
|
return 0;
|
|
else
|
|
return -ENOENT;
|
|
}
|
|
|
|
int sysfs_permission(struct inode *inode, int mask)
|
|
{
|
|
struct sysfs_dirent *sd;
|
|
|
|
if (mask & MAY_NOT_BLOCK)
|
|
return -ECHILD;
|
|
|
|
sd = inode->i_private;
|
|
|
|
mutex_lock(&sysfs_mutex);
|
|
sysfs_refresh_inode(sd, inode);
|
|
mutex_unlock(&sysfs_mutex);
|
|
|
|
return generic_permission(inode, mask);
|
|
}
|