/* * 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 = GLOBAL_ROOT_UID;	iattrs->ia_gid = GLOBAL_ROOT_GID;	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; 	if (!sd->s_iattr) {		sd->s_iattr = sysfs_init_inode_attrs(sd);		if (!sd->s_iattr)			return -ENOMEM;	} 	iattrs = sd->s_iattr;	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, umode_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 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)		set_nlink(inode, sd->s_dir.subdirs + 2);} 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);	clear_inode(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) {		WARN(1, KERN_WARNING "sysfs: can not remove '%s', no directory\n",			name);		return -ENOENT;	} 	sysfs_addrm_start(&acxt, dir_sd); 	sd = sysfs_find_dirent(dir_sd, ns, name);	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);}