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/**
@file     path_tools.h
@brief    Tools for working with 'struct path'
@details  Copyright (c) 2024 Acronis International GmbH
@author   Bruce Wang (bruce.wang@acronis.com)
@since    $Id: $
*/

#pragma once

#include "file_contexts.h"
#include "file_key_tools.h"

#include <linux/fcntl.h>
#include <linux/magic.h>

static inline bool make_file_context_info(file_context_info_t *info
                                        , const struct path *path
                                        , int flags
                                        , uint64_t low, uint64_t high
                                        , uint64_t pid_version)
{
	if (!path || !path->dentry || !path->dentry->d_inode)
	{
		return false;
	}
	make_key_from_inode(&info->msg_info.key.file_key, path->dentry->d_inode);

#ifdef HAVE_INODE_GET_MTIME
	info->msg_info.key.i_mtime.tv_sec = inode_get_mtime(path->dentry->d_inode).tv_sec;
	info->msg_info.key.i_mtime.tv_nsec = inode_get_mtime(path->dentry->d_inode).tv_nsec;
#else
	info->msg_info.key.i_mtime.tv_sec = path->dentry->d_inode->i_mtime.tv_sec;
	info->msg_info.key.i_mtime.tv_nsec = path->dentry->d_inode->i_mtime.tv_nsec;
#endif

#ifdef HAVE_INODE_GET_CTIME
	info->msg_info.key.i_ctime.tv_sec = inode_get_ctime(path->dentry->d_inode).tv_sec;
	info->msg_info.key.i_ctime.tv_nsec = inode_get_ctime(path->dentry->d_inode).tv_nsec;
#else
	info->msg_info.key.i_ctime.tv_sec = path->dentry->d_inode->i_ctime.tv_sec;
	info->msg_info.key.i_ctime.tv_nsec = path->dentry->d_inode->i_ctime.tv_nsec;
#endif
	info->pid_version = pid_version;
	if ((flags & O_ACCMODE) <= O_RDWR)
	{
		flags += 1;
	}
	info->flags = flags;
	info->low = low;
	info->high = high;
	return true;
}

static inline bool make_file_context_info_with_inode(file_context_info_t *info, const struct inode *inode, uint64_t unique_pid)
{
	make_key_from_inode(&info->msg_info.key.file_key, inode);

#ifdef HAVE_INODE_GET_MTIME
	info->msg_info.key.i_mtime.tv_sec = inode_get_mtime(inode).tv_sec;
	info->msg_info.key.i_mtime.tv_nsec = inode_get_mtime(inode).tv_nsec;
#else
	info->msg_info.key.i_mtime.tv_sec = inode->i_mtime.tv_sec;
	info->msg_info.key.i_mtime.tv_nsec = inode->i_mtime.tv_nsec;
#endif

#ifdef HAVE_INODE_GET_CTIME
	info->msg_info.key.i_ctime.tv_sec = inode_get_ctime(inode).tv_sec;
	info->msg_info.key.i_ctime.tv_nsec = inode_get_ctime(inode).tv_nsec;
#else
	info->msg_info.key.i_ctime.tv_sec = inode->i_ctime.tv_sec;
	info->msg_info.key.i_ctime.tv_nsec = inode->i_ctime.tv_nsec;
#endif
	// currently this function uses unique_pid only
	info->unique_pid = unique_pid;
	return true;
}

#ifndef NSFS_MAGIC
#define NSFS_MAGIC 0x6e736673
#endif

#ifndef SYSFS_MAGIC
#define SYSFS_MAGIC 0x62656572
#endif

#ifndef PROC_SUPER_MAGIC
#define PROC_SUPER_MAGIC 0x9fa0
#endif

#ifndef DEBUGFS_MAGIC
#define DEBUGFS_MAGIC 0x64626720
#endif

#ifndef SECURITYFS_MAGIC
#define SECURITYFS_MAGIC 0x73636673
#endif

#ifndef CGROUP_SUPER_MAGIC
#define CGROUP_SUPER_MAGIC	0x27e0eb
#endif

#ifndef CGROUP2_SUPER_MAGIC
#define CGROUP2_SUPER_MAGIC	0x63677270
#endif

#ifndef BPF_FS_MAGIC
#define BPF_FS_MAGIC	0xcafe4a11
#endif

#ifndef TRACEFS_MAGIC
#define TRACEFS_MAGIC          0x74726163
#endif

#ifndef FUSECTL_SUPER_MAGIC
#define FUSECTL_SUPER_MAGIC 0x65735543
#endif

#ifndef PSTOREFS_MAGIC
#define PSTOREFS_MAGIC		0x6165676C
#endif

#ifndef CONFIGFS_MAGIC
#define CONFIGFS_MAGIC	0x62656570
#endif

#ifndef HUGETLBFS_MAGIC
#define HUGETLBFS_MAGIC 	0x958458f6
#endif

#ifndef MQUEUE_MAGIC
#define MQUEUE_MAGIC 0x19800202
#endif

#ifndef DEVPTS_SUPER_MAGIC
#define DEVPTS_SUPER_MAGIC 0x1cd1
#endif

#ifndef SELINUX_MAGIC
#define SELINUX_MAGIC		0xf97cff8c
#endif

static inline bool inode_is_usable(const struct inode *inode)
{
	if (!inode)
	{
		return false;
	}

	if (!inode->i_sb)
	{
		return false;
	}

	return true;
}

// Checks for bare minimum requirements for 'path' to be any sort of reasonable
static inline bool path_is_usable(const struct path *path)
{
	struct dentry *dentry;

	if (!path->mnt)
		return false;

	dentry = path->dentry;
	if (!dentry)
	{
		return false;
	}

	return inode_is_usable(dentry->d_inode);
}

static inline int magic_ok(unsigned long magic)
{
	return magic != BPF_FS_MAGIC
			&& magic != CGROUP_SUPER_MAGIC
			&& magic != CGROUP2_SUPER_MAGIC
			&& magic != CONFIGFS_MAGIC
			&& magic != DEBUGFS_MAGIC
			&& magic != DEVPTS_SUPER_MAGIC
			&& magic != FUSECTL_SUPER_MAGIC
			&& magic != HUGETLBFS_MAGIC
			&& magic != MQUEUE_MAGIC
			&& magic != NSFS_MAGIC
			&& magic != PROC_SUPER_MAGIC
			&& magic != PSTOREFS_MAGIC
			&& magic != SECURITYFS_MAGIC
			&& magic != SELINUX_MAGIC
			&& magic != SYSFS_MAGIC
			&& magic != TRACEFS_MAGIC
			;
}

static inline int sb_ok(const struct super_block *sb)
{
	return sb && magic_ok(sb->s_magic);
}

static inline bool check_if_usable_inode_valid(const struct inode *inode)
{
	umode_t mode;
	if (!sb_ok(inode->i_sb))
	{
		return false;
	}

	mode = inode->i_mode;
	if ((S_ISREG(mode)) || (S_ISDIR(mode)))
		return true;
	else
		return false;
}

static inline bool inode_is_valid(const struct inode *inode)
{
	if (!inode_is_usable(inode))
	{
		return false;
	}

	return check_if_usable_inode_valid(inode);
}

static inline bool path_is_valid(const struct path *path)
{
	if (!path_is_usable(path))
	{
		return false;
	}

	return check_if_usable_inode_valid(path->dentry->d_inode);
}

static inline bool file_is_valid(struct file* f)
{
	return path_is_valid(&f->f_path);
}