/* *  linux/fs/attr.c * *  Copyright (C) 1991, 1992  Linus Torvalds *  changes by Thomas Schoebel-Theuer */ #include <linux/module.h>#include <linux/time.h>#include <linux/mm.h>#include <linux/string.h>#include <linux/smp_lock.h>#include <linux/capability.h>#include <linux/fsnotify.h>#include <linux/fcntl.h>#include <linux/quotaops.h>#include <linux/security.h> /* Taken over from the old code... */ /* POSIX UID/GID verification for setting inode attributes. */int inode_change_ok(struct inode *inode, struct iattr *attr){	int retval = -EPERM;	unsigned int ia_valid = attr->ia_valid; 	/* If force is set do it anyway. */	if (ia_valid & ATTR_FORCE)		goto fine; 	/* Make sure a caller can chown. */	if ((ia_valid & ATTR_UID) &&	    (current->fsuid != inode->i_uid ||	     attr->ia_uid != inode->i_uid) && !capable(CAP_CHOWN))		goto error; 	/* Make sure caller can chgrp. */	if ((ia_valid & ATTR_GID) &&	    (current->fsuid != inode->i_uid ||	    (!in_group_p(attr->ia_gid) && attr->ia_gid != inode->i_gid)) &&	    !capable(CAP_CHOWN))		goto error; 	/* Make sure a caller can chmod. */	if (ia_valid & ATTR_MODE) {		if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))			goto error;		/* Also check the setgid bit! */		if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid :				inode->i_gid) && !capable(CAP_FSETID))			attr->ia_mode &= ~S_ISGID;	} 	/* Check for setting the inode time. */	if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET)) {		if (current->fsuid != inode->i_uid && !capable(CAP_FOWNER))			goto error;	}fine:	retval = 0;error:	return retval;} EXPORT_SYMBOL(inode_change_ok); int inode_setattr(struct inode * inode, struct iattr * attr){	unsigned int ia_valid = attr->ia_valid; 	if (ia_valid & ATTR_SIZE &&	    attr->ia_size != i_size_read(inode)) {		int error = vmtruncate(inode, attr->ia_size);		if (error)			return error;	} 	if (ia_valid & ATTR_UID)		inode->i_uid = attr->ia_uid;	if (ia_valid & ATTR_GID)		inode->i_gid = attr->ia_gid;	if (ia_valid & ATTR_ATIME)		inode->i_atime = timespec_trunc(attr->ia_atime,						inode->i_sb->s_time_gran);	if (ia_valid & ATTR_MTIME)		inode->i_mtime = timespec_trunc(attr->ia_mtime,						inode->i_sb->s_time_gran);	if (ia_valid & ATTR_CTIME)		inode->i_ctime = timespec_trunc(attr->ia_ctime,						inode->i_sb->s_time_gran);	if (ia_valid & ATTR_MODE) {		umode_t mode = attr->ia_mode; 		if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))			mode &= ~S_ISGID;		inode->i_mode = mode;	}	mark_inode_dirty(inode); 	return 0;}EXPORT_SYMBOL(inode_setattr); int notify_change(struct dentry * dentry, struct iattr * attr){	struct inode *inode = dentry->d_inode;	mode_t mode;	int error;	struct timespec now;	unsigned int ia_valid = attr->ia_valid; 	mode = inode->i_mode;	now = current_fs_time(inode->i_sb); 	attr->ia_ctime = now;	if (!(ia_valid & ATTR_ATIME_SET))		attr->ia_atime = now;	if (!(ia_valid & ATTR_MTIME_SET))		attr->ia_mtime = now;	if (ia_valid & ATTR_KILL_SUID) {		attr->ia_valid &= ~ATTR_KILL_SUID;		if (mode & S_ISUID) {			if (!(ia_valid & ATTR_MODE)) {				ia_valid = attr->ia_valid |= ATTR_MODE;				attr->ia_mode = inode->i_mode;			}			attr->ia_mode &= ~S_ISUID;		}	}	if (ia_valid & ATTR_KILL_SGID) {		attr->ia_valid &= ~ ATTR_KILL_SGID;		if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {			if (!(ia_valid & ATTR_MODE)) {				ia_valid = attr->ia_valid |= ATTR_MODE;				attr->ia_mode = inode->i_mode;			}			attr->ia_mode &= ~S_ISGID;		}	}	if (!attr->ia_valid)		return 0; 	if (ia_valid & ATTR_SIZE)		down_write(&dentry->d_inode->i_alloc_sem); 	if (inode->i_op && inode->i_op->setattr) {		error = security_inode_setattr(dentry, attr);		if (!error)			error = inode->i_op->setattr(dentry, attr);	} else {		error = inode_change_ok(inode, attr);		if (!error)			error = security_inode_setattr(dentry, attr);		if (!error) {			if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||			    (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid))				error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;			if (!error)				error = inode_setattr(inode, attr);		}	} 	if (ia_valid & ATTR_SIZE)		up_write(&dentry->d_inode->i_alloc_sem); 	if (!error)		fsnotify_change(dentry, ia_valid); 	return error;} EXPORT_SYMBOL(notify_change);