// SPDX-License-Identifier: GPL-2.0-or-later

/* seitan - Syscall Expressive Interpreter, Transformer and Notifier
 *
 * cooker/calls/fs.c - Description of known filesystem-related system calls
 *
 * Copyright 2023 Red Hat GmbH
 * Author: Stefano Brivio <sbrivio@redhat.com>
 */

/*
stat ?
fstat ?
lstat ?

lseek ?

fcntl ?
flock ~
fsync
fdatasync
truncate
ftruncate

getdents
getcwd
chdir
fchdir
mkdir
rmdir

rename

creat

link
unlink
symlink
readlink

chmod
fchmod
chown
fchown
fchownat
lchown
umask

mknod
mknodat

mount
umount2
swapon
swapoff
*/

#include <asm-generic/unistd.h>
#include <sys/syscall.h>

#define _GNU_SOURCE
#include <sys/stat.h>
#include <sys/xattr.h>
#include <fcntl.h>
#include <linux/limits.h>

#include "../cooker.h"
#include "../calls.h"

static struct num modes[] = {
	{ "S_ISUID",	S_ISUID },
	{ "S_ISGID",	S_ISGID },
	{ "S_IRWXU",	S_IRWXU },
	{ "S_IRUSR",	S_IRUSR },
	{ "S_IWUSR",	S_IWUSR },
	{ "S_IXUSR",	S_IXUSR },
	{ "S_IRWXG",	S_IRWXG },
	{ "S_IRGRP",	S_IRGRP },
	{ "S_IWGRP",	S_IWGRP },
	{ "S_IXGRP",	S_IXGRP },
	{ "S_IRWXO",	S_IRWXO },
	{ "S_IROTH",	S_IROTH },
	{ "S_IWOTH",	S_IWOTH },
	{ "S_IXOTH",	S_IXOTH },
	{ "S_ISVTX",	S_ISVTX },
	{ 0 },
};

static struct num types[] = {
	{ "S_IFSOCK",	S_IFSOCK },
	{ "S_IFLNK",	S_IFLNK },
	{ "S_IFREG",	S_IFREG },
	{ "S_IFBLK",	S_IFBLK },
	{ "S_IFDIR",	S_IFDIR },
	{ "S_IFCHR",	S_IFCHR },
	{ "S_IFIFO",	S_IFIFO },
	{ 0 },
};

static struct arg mknod_args[] = {
	{ 0,
		{
			"path",		STRING,			0,
			0,	PATH_MAX,
			{ 0 }
		}
	},
	{ 1,
		{
			"mode",		INT,			FLAGS | MASK,
			0,	0,
			{ .d_num = modes },
		}
	},
	{ 1,
		{
			"type",		INT,			FLAGS | MASK,
			0,	0,
			{ .d_num = types },
		}
	},
	{ 2,
		{
			"major",	GNU_DEV_MAJOR,		0,
			0,	0,
			{ 0 },
		}
	},
	{ 2,
		{
			"minor",	GNU_DEV_MINOR,		0,
			0,	0,
			{ 0 },
		}
	},
	{ 0 }
};

static struct arg mknodat_args[] = {
	/* No dirfd: we only support absolute paths at the moment */
	{ 1,
		{
			"path",		STRING,			0,
			0,	PATH_MAX,
			{ 0 }
		}
	},
	{ 2,
		{
			"mode",		INT,			FLAGS | MASK,
			0,	0,
			{ .d_num = modes },
		}
	},
	{ 2,
		{
			"type",		INT,			FLAGS | MASK,
			0,	0,
			{ .d_num = types },
		}
	},
	{ 3,
		{
			"major",	GNU_DEV_MAJOR,		0,
			0,	0,
			{ 0 },
		}
	},
	{ 3,
		{
			"minor",	GNU_DEV_MINOR,		0,
			0,	0,
			{ 0 },
		}
	},
	{ 0 }
};

static struct arg chown_args[] = {
	{ 0,
		{
			"path",		STRING,			0,
			0,	PATH_MAX,
			{ 0 }
		}
	},
	{ 1,
		{
			"uid",		UID_T,			0,
			0,	0,
			{ .d_num = modes },
		}
	},
	{ 2,
		{
			"gid",	GID_T,		0,
			0,	0,
			{ 0 },
		}
	},
	{ 0 }
};

static struct num xattr_flags[] = {
	{ "create",	XATTR_CREATE },
	{ "replace",	XATTR_REPLACE },
	{ 0 },
};

static struct arg fsetxattr_args[] = {
	{ 0,
		{
			"fd",		INT,		FD,	0,	0,
			{ 0 }
		}
	},
	{ 0,
		{
			"path",		FDPATH,		FD,	0,	0,
			{ 0 }
		}
	},
	{ 1,
		{
			"name",		STRING,		0,	0,
			XATTR_NAME_MAX,
			{ 0 }
		}
	},
	{ 2,
		{
			"value",	STRING,		WBUF,	0,
			XATTR_SIZE_MAX,
			{ 0 }
		}
	},
	{ 3,
		{
			"size",		LONG,		0,	0,	0,
			{ 0 }
		}
	},
	{ 4,
		{
			"flags",	INT,		FLAGS,	0,	0,
			{ .d_num = xattr_flags }
		}
	},
	{ 0 },
};

static struct arg fremovexattr_args[] = {
	{ 0,
		{
			"fd",		INT,		FD,	0,	0,
			{ 0 }
		}
	},
	{ 0,
		{
			"path",		FDPATH,		FD,	0,	0,
			{ 0 }
		}
	},
	{ 1,
		{
			"name",		STRING,		0,	0,
			XATTR_NAME_MAX,
			{ 0 }
		}
	},
	{ 0 },
};

/* enum fid_type copied (without comments) from include/linux/exportfs.h of
 * Linux 6.9. Just copied and pasted like that? Is that an acceptable practice?
 * Well then, let's say I _vendored_ it.
 */
enum fid_type {
	FILEID_ROOT = 0,
	FILEID_INO32_GEN = 1,
	FILEID_INO32_GEN_PARENT = 2,
	FILEID_BTRFS_WITHOUT_PARENT = 0x4d,
	FILEID_BTRFS_WITH_PARENT = 0x4e,
	FILEID_BTRFS_WITH_PARENT_ROOT = 0x4f,
	FILEID_UDF_WITHOUT_PARENT = 0x51,
	FILEID_UDF_WITH_PARENT = 0x52,
	FILEID_NILFS_WITHOUT_PARENT = 0x61,
	FILEID_NILFS_WITH_PARENT = 0x62,
	FILEID_FAT_WITHOUT_PARENT = 0x71,
	FILEID_FAT_WITH_PARENT = 0x72,
	FILEID_INO64_GEN = 0x81,
	FILEID_INO64_GEN_PARENT = 0x82,
	FILEID_LUSTRE = 0x97,
	FILEID_BCACHEFS_WITHOUT_PARENT = 0xb1,
	FILEID_BCACHEFS_WITH_PARENT = 0xb2,
	FILEID_KERNFS = 0xfe,
	FILEID_INVALID = 0xff,
};

static struct num handle_types[] = {
	{ "root",			FILEID_ROOT },
	{ "ino32_gen",			FILEID_INO32_GEN },
	{ "ino32_gen_parent",		FILEID_INO32_GEN_PARENT },
	{ "btrfs_with_parent",		FILEID_BTRFS_WITH_PARENT },
	{ "btrfs_without_parent",	FILEID_BTRFS_WITHOUT_PARENT },
	{ "udf_with_parent",		FILEID_UDF_WITH_PARENT },
	{ "udf_without_parent",		FILEID_UDF_WITHOUT_PARENT },
	{ "fat_with_parent",		FILEID_FAT_WITH_PARENT },
	{ "fat_without_parent",		FILEID_FAT_WITHOUT_PARENT },
	{ "ino64_gen",			FILEID_INO64_GEN },
	{ "ino64_gen_parent",		FILEID_INO64_GEN_PARENT },
	{ "lustre",			FILEID_LUSTRE },
	{ "bcachefs_with_parent",	FILEID_BCACHEFS_WITH_PARENT },
	{ "bcachefs_without_parent",	FILEID_BCACHEFS_WITHOUT_PARENT },
	{ "kernfs",			FILEID_KERNFS },
	{ "invalid",			FILEID_INVALID },
	{ 0 },
};

static struct field file_handle[] = {
	{
		"handle_bytes",	LONG,		SIZE,
		offsetof(struct file_handle, handle_bytes),
		0,
		{ .d_size = (intptr_t)&file_handle[2] },
	},
	{
		"handle_type",	INT,		FLAGS,
		offsetof(struct file_handle, handle_type),
		0,
		{ .d_num = handle_types },
	},

	{
		"f_handle",	STRING,		0,
		offsetof(struct file_handle, f_handle),
		MAX_HANDLE_SZ,
		{ 0 },
	},
	{ 0 }
};

static struct num open_flags[] = {
	{ "rdonly",	O_RDONLY },
	{ "wronly",	O_WRONLY },
	{ "rdwr",	O_RDWR },
	{ 0 },
};

static struct arg open_by_handle_at_args[] = {
	{ 0,
		{
			"mount",	FDMOUNT,	0,		0,
			0,
			{ 0 }
		}
	},
	{ 0,
		{
			"mount_fd",	INT,		0,		0,
			0,
			{ 0 }
		}
	},
	{ 1,
		{
			"handle",	STRUCT,		0,		0,
			sizeof(struct file_handle) + MAX_HANDLE_SZ,
			{ .d_struct = file_handle }
		}
	},
	{ 2,
		{
			"flags",	INT,		MASK | FLAGS,	0,
			0,
			{ .d_num = open_flags }
		}
	},
	{ 0 },
};

struct call syscalls_fs[] = {
	{ __NR_mknod, "mknod", mknod_args },
	{ __NR_mknodat, "mknodat", mknodat_args },

	{ __NR_chown, "chown", chown_args },
	{ __NR_lchown, "lchown", chown_args },

	{ __NR_fsetxattr, "fsetxattr", fsetxattr_args },
	/* fd,  name, value, size, flags */

	{ __NR_fremovexattr, "fremovexattr", fremovexattr_args },
	/* fd, name */

	{ __NR_open_by_handle_at, "open_by_handle_at", open_by_handle_at_args },

	{ 0 },
};