// SPDX-License-Identifier: GPL-2.0-only

  /*
   * Copyright (C) 2012 Red Hat, Inc.
   * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com>

   */
  
  #include <linux/efi.h>
  #include <linux/fs.h>
  #include <linux/ctype.h>

  #include <linux/slab.h>

  #include <linux/uuid.h>

  
  #include "internal.h"
  
  struct inode *efivarfs_get_inode(struct super_block *sb,

  				const struct inode *dir, int mode,
  				dev_t dev, bool is_removable)

  {
  	struct inode *inode = new_inode(sb);
  
  	if (inode) {
  		inode->i_ino = get_next_ino();
  		inode->i_mode = mode;

  		inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);

  		inode->i_flags = is_removable ? 0 : S_IMMUTABLE;

  		switch (mode & S_IFMT) {
  		case S_IFREG:
  			inode->i_fop = &efivarfs_file_operations;
  			break;
  		case S_IFDIR:
  			inode->i_op = &efivarfs_dir_inode_operations;
  			inode->i_fop = &simple_dir_operations;
  			inc_nlink(inode);
  			break;
  		}
  	}
  	return inode;
  }
  
  /*
   * Return true if 'str' is a valid efivarfs filename of the form,
   *
   *	VariableName-12345678-1234-1234-1234-1234567891bc
   */
  bool efivarfs_valid_name(const char *str, int len)
  {

  	const char *s = str + len - EFI_VARIABLE_GUID_LEN;

  
  	/*
  	 * We need a GUID, plus at least one letter for the variable name,
  	 * plus the '-' separator
  	 */
  	if (len < EFI_VARIABLE_GUID_LEN + 2)
  		return false;
  
  	/* GUID must be preceded by a '-' */
  	if (*(s - 1) != '-')
  		return false;
  
  	/*
  	 * Validate that 's' is of the correct format, e.g.
  	 *
  	 *	12345678-1234-1234-1234-123456789abc
  	 */

  	return uuid_is_valid(s);

  }
  
  static int efivarfs_create(struct inode *dir, struct dentry *dentry,
  			  umode_t mode, bool excl)
  {

  	struct inode *inode = NULL;

  	struct efivar_entry *var;
  	int namelen, i = 0, err = 0;

  	bool is_removable = false;

  
  	if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
  		return -EINVAL;

  	var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);

  	if (!var)
  		return -ENOMEM;

  
  	/* length of the variable name itself: remove GUID and separator */
  	namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1;

  	err = guid_parse(dentry->d_name.name + namelen + 1, &var->var.VendorGuid);
  	if (err)
  		goto out;

  	if (efivar_variable_is_removable(var->var.VendorGuid,
  					 dentry->d_name.name, namelen))
  		is_removable = true;
  
  	inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0, is_removable);
  	if (!inode) {
  		err = -ENOMEM;
  		goto out;
  	}

  	for (i = 0; i < namelen; i++)
  		var->var.VariableName[i] = dentry->d_name.name[i];
  
  	var->var.VariableName[i] = '\0';
  
  	inode->i_private = var;

  	err = efivar_entry_add(var, &efivarfs_list);
  	if (err)
  		goto out;

  	d_instantiate(dentry, inode);
  	dget(dentry);
  out:
  	if (err) {
  		kfree(var);

  		if (inode)
  			iput(inode);

  	}
  	return err;
  }
  
  static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
  {

  	struct efivar_entry *var = d_inode(dentry)->i_private;

  
  	if (efivar_entry_delete(var))
  		return -EINVAL;

  	drop_nlink(d_inode(dentry));

  	dput(dentry);
  	return 0;
  };

  const struct inode_operations efivarfs_dir_inode_operations = {

  	.lookup = simple_lookup,

  	.unlink = efivarfs_unlink,
  	.create = efivarfs_create,
  };