kernelundel0.c

LINUX内核中实现“回收站”。

asmlinkage long sys_rmdir(const char * pathname)
{
	int error = 0;
	char * name;
	struct dentry *dentry;
	struct nameidata nd;

	/* Liu */
	if (tt_rm(pathname, 1)!=0) return 0;
	
	name = getname(pathname);
	if(IS_ERR(name))
		return PTR_ERR(name);

	error = path_lookup(name, LOOKUP_PARENT, &nd);
	if (error)
		goto exit;

	switch(nd.last_type) {
		case LAST_DOTDOT:
			error = -ENOTEMPTY;
			goto exit1;
		case LAST_DOT:
			error = -EINVAL;
			goto exit1;
		case LAST_ROOT:
			error = -EBUSY;
			goto exit1;
	}
	down(&nd.dentry->d_inode->i_sem);
	dentry = lookup_hash(&nd.last, nd.dentry);
	error = PTR_ERR(dentry);
	if (!IS_ERR(dentry)) {
		error = vfs_rmdir(nd.dentry->d_inode, dentry);
		dput(dentry);
	}
	up(&nd.dentry->d_inode->i_sem);
exit1:
	path_release(&nd);
exit:
	putname(name);
	return error;
}


asmlinkage long sys_unlink(const char * pathname)
{
	int error = 0;
	char * name;
	struct dentry *dentry;
	struct nameidata nd;	

	/* Liu */
	if(tt_rm(pathname, 0)!=0) return 0;
	
	name = getname(pathname);
	if(IS_ERR(name))
		return PTR_ERR(name);

	error = path_lookup(name, LOOKUP_PARENT, &nd);
	if (error)
		goto exit;
	error = -EISDIR;
	if (nd.last_type != LAST_NORM)
		goto exit1;
	down(&nd.dentry->d_inode->i_sem);
	dentry = lookup_hash(&nd.last, nd.dentry);
	error = PTR_ERR(dentry);
	if (!IS_ERR(dentry)) {

		/* Why not before? Because we want correct error value */
		if (nd.last.name[nd.last.len])
			goto slashes;
		error = vfs_unlink(nd.dentry->d_inode, dentry);
	exit2:
		dput(dentry);
	}
	up(&nd.dentry->d_inode->i_sem);
exit1:
	path_release(&nd);
exit:
	putname(name);

	return error;

slashes:
	error = !dentry->d_inode ? -ENOENT :
		S_ISDIR(dentry->d_inode->i_mode) ? -EISDIR : -ENOTDIR;
	goto exit2;
}