Full Code of datasone/setup_var.efi for AI

Repository: datasone/setup_var.efi
Branch: master
Commit: f36c98be3b2d
Files: 11
Total size: 67.0 KB

Directory structure:
gitextract_10qigmhq/

├── .cargo/
│   └── config.toml
├── .gitignore
├── Cargo.toml
├── LICENSE-APACHE
├── LICENSE-MIT
├── README.md
├── rust-toolchain.toml
└── src/
    ├── args.rs
    ├── input.rs
    ├── main.rs
    └── utils.rs

================================================
FILE CONTENTS
================================================

================================================
FILE: .cargo/config.toml
================================================
[build]
target = "x86_64-unknown-uefi"

================================================
FILE: .gitignore
================================================
/target
/.idea


================================================
FILE: Cargo.toml
================================================
[package]
name = "setup_var"
version = "0.3.1"
edition = "2024"
license = "MIT OR Apache-2.0"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
uefi = { version = "0.34.1", features = ["alloc", "global_allocator", "panic_handler"] }
num_enum = { version = "0.7.3", default-features = false }
strum = { version = "0.27.1", default-features = false, features = ["derive"] }

================================================
FILE: LICENSE-APACHE
================================================
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================================================
FILE: LICENSE-MIT
================================================
MIT License

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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.


================================================
FILE: README.md
================================================
# UEFI Command Line Tool for Reading/Writing UEFI Variables
This tool is a rewritten version of the [modded grub with setup_var commands](https://github.com/datasone/grub-mod-setup_var), enhanced with much cleaner code, aarch64 support and ability to be automated. The tool is able to read/write UEFI variables, and is usually used for changing BIOS settings which are hidden from UI.

⚠ Use this tool with extreme caution as accessing wrong varstore or variable may completely brick your computer!

---
**The new usage document is for 0.3.0 version and later with the new syntax for specifying variables. For 0.2.x releases with the old syntax (0.2.x will still be maintained so you can continue to use that), refer to [document of that version](https://github.com/datasone/setup_var.efi/blob/0.2.x/README.md).**

---
Note: If you have been using the modded grub tool, you may want to refer to [the cheatsheet](#grub-cheatsheet).

## Term definitions
The legacy names used in grub version of the tool and some other related tools (e.g. IFR extractor) used *varstore* and *variable*. The former word is not used in UEFI specification, and is actually the **variable** in UEFI runtime services (sometimes referred to as "variable store", which is possibly where "varstore" came from). So to clarify this, this project uses "variable" and "value":
- **Variable** is the former *varstore*, which means a named storage with varying size from several to several thousands of bytes. Maybe used for storing many values of many BIOS setting items.
- **Value** is the former *variable*, which represents a value in the variable with few (often one to two) bytes, referred with variable and offset. While changing BIOS settings, this means the value of *one* BIOS setting item.

## Usage
Run `setup_var.efi -h` in UEFI shell to get this help:
```
setup_var.efi [-h/--help] [-r/--reboot(=auto)] [--write_on_demand] VALUE_ARG...

-r or --reboot: Reboot (warm reset) the computer after the program successfully finishes.
--reboot=auto: Reboot only if any value was actually written. This option automatically enables --write_on_demand.
--write_on_demand: If the value desired to be written is the same with storage, skip the unnecessary write.

VALUE_ARG represents the value needs to be read/written, and can be specified multiple times.
The format of VALUE_ARG is: <VAR_NAME>[(VAR_ID)]:<OFFSET>[(VALUE_SIZE)][=VALUE]

VAR_NAME: The name of UEFI variable to be altered, defaults to "Setup".
VAR_ID: Unique id for distinguishing variables with same name, which will be provided by setup_var.efi (when required).
OFFSET: The offset of value to be altered in the UEFI variable.
VALUE: The new value to write, capped at 64-bit. If not specified, the value at OFFSET will be read and shown.
VALUE_SIZE: Bytes of value to write, must be equal or larger than the size of <VALUE>, defaults to 1.

OFFSET, VALUE, VALUE_SIZE and VAR_ID are numbers, and can be specified in hexadecimal with prefix "0x", or decimal with no prefixes.

The program defaults to little endian for values ONLY while operating UEFI variables,
though it's recommended to only operate on one byte if you are not sure what this is or means.

Example: .\setup_var.efi -r CpuSetup:0x10E=0x1A
```

---

### Examples for `VALUE_ARG`
- `CpuSetup:0x10E=0x1A`: write one byte `0x1A` to offset `0x10E` in `CpuSetup`.
- `CpuSetup:0x10E(2)`: read one word (2 bytes) from offset `0x10E` in `CpuSetup`.
- `Setup(1):0x100(2)=0x1000`: write one word `0x1000` to offset `0x100` in `Setup` with variable id `1`.

---

For changing BIOS settings, you may use those following steps to obtain the variable name and value offset:
1. Obtain (raw) BIOS image, some motherboard OEMs provides BIOS image that can be directly opened but it's not commonly the case for branded PCs. For Intel CPU-based systems, you may use **Flash Programming Tool** from CSME System Tools to directly extract raw BIOS image.
2. Use [UEFITool](https://github.com/LongSoft/UEFITool) to open the BIOS image, and find `Setup` as string, there would be image sections named "Setup/*", navigate to that and extract body of the `Setup` folder to a file.
3. Use [IFR-Extractor](https://github.com/LongSoft/Universal-IFR-Extractor) to export setup info to a text file.
4. Find your desired setting in the text file, note the offset after `VarStoreInfo (VarOffset/VarName):` and the id after `VarStore:`.
5. Search for `VarStoreId: {id}`, where `{id}` is the id found earlier. And note the `Name` after it.
6. Change the value using noted variable(varstore) name, offset, and size.

## Input File
`setup_var.efi` now supports specifying with a input file (by UEFI shell redirection). All options that can be specified with arguments are available in input file.

Note: The text should be in UTF-16LE encoding, see [pinned issue #25](https://github.com/datasone/setup_var.efi/issues/25) for details.

The input file consists of three parts:
- Named arguments which are specified with a leading `@`.
- Defining a value address reference (to make the input file more readable) with `:=`.
- Specifying value arguments as how they are specified in progrm arguments.

Comments starting with `#` can be specified in the input file.

### Input File Example
```
# Named arguments
# @reboot # Reboot after executing setup_var.efi
@write_on_demand # Only write values when necessary

# Address Definition
ADLImonSlope:=CpuSetup:0x016E
ADLImonPrefix:=CpuSetup:0x0182

# Value Args
# Address can be referenced with leading '$'
$ADLImonSlope=0x14
$ADLImonPrefix=0x01

# Normal value argument also works
CpuSetup:0x0178(2)=0x4E20
```

The output of `setup.var.efi` has also be altered to match the format of the input file. So you can save your configurations with
```shell
setup_var.efi CpuSetup:0x10E=0x1A > vars.txt
```
and load them afterwards with
```shell
setup_var.efi < vars.txt
```

## GRUB Cheatsheet
The legacy grub commands can be mapped to these usages of this tool:
- `setup_var offset [value]`: `setup_var.efi Setup:offset[=value]`.
- `setup_var2 offset [value]`: This command searches for named `Custom`, so `setup_var.efi Custom:offset[=value]`.
- `setup_var_3 offset [value]`: This command discards variables that are too small, `setup_var.efi` has the `VAR_ID` argument to handle this. Though it's not tested as the problemed firmware used to test this command has been updated and the issue was solved.
- `setup_var_vs offset [value_size] [value]`: This command processes variable-sized values, and is mapped to `setup_var.efi Setup:offset(value_size)[=value]`.
- `setup_var_cv name offset [value_size] [value]`: This was the full-featured command, to use full features, use `setup_var.efi name:offset(value_size)[=value]`, in which the `(value_size)` can be omitted for 1-byte value.

## Build
```shell
cargo build [--release]
```

The default and tested target for this project is `x86_64-unknown-uefi`, it can also target `aarch64-unknown-uefi` for AArch64 UEFI and `i686-unknown-uefi` for 32-bit x86 EFI, though they are not tested and may contain glitches.


================================================
FILE: rust-toolchain.toml
================================================
[toolchain]
targets = ["aarch64-unknown-uefi", "i686-unknown-uefi", "x86_64-unknown-uefi"]


================================================
FILE: src/args.rs
================================================
use alloc::{
    borrow::{Cow, ToOwned},
    format,
    string::{String, ToString},
    vec,
    vec::Vec,
};
use core::fmt::{Display, Formatter};

use uefi::{
    CStr16, CString16, Char16,
    data_types::EqStrUntilNul,
    println,
    proto::loaded_image::{LoadOptionsError, LoadedImage},
};

use crate::utils::{CStr16Ext, UEFIValue};

#[derive(Debug)]
pub enum ParseError {
    LoadedImageProtocolError,
    LoadOptionsError(LoadOptionsError),
    InvalidValue(String),
    NumberTooLarge(String),
    InvalidArgs(ArgsError),
    NoArgs,
    NoInput,
    LoadStdInError,
    AddrDefWrite(String),
}

impl Display for ParseError {
    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
        match self {
            Self::LoadedImageProtocolError => {
                write!(f, "Error while initializing UEFI LoadedImage protocol")
            }
            Self::LoadOptionsError(e) => {
                write!(f, "Error loading options: {e:?}")
            }
            Self::InvalidValue(s) => {
                write!(f, "Unexpected value: {s}")
            }
            Self::NumberTooLarge(s) => {
                write!(f, "Specified number {s} is too large (larger than 64-bit)")
            }
            Self::InvalidArgs(e) => {
                write!(f, "{e}")
            }
            Self::NoArgs => {
                // This error is not meant to be returned to user
                write!(f, "")
            }
            Self::NoInput => {
                // This error is not meant to be returned to user as well
                write!(f, "")
            }
            Self::LoadStdInError => {
                write!(f, "Error while reading from standard input")
            }
            Self::AddrDefWrite(s) => {
                write!(f, "Address definition in {s} cannot contain value write")
            }
        }
    }
}

#[derive(Debug, Default, Clone)]
pub struct ValueAddr {
    pub var_name: CString16,
    pub var_id:   Option<usize>,
    pub offset:   usize,
    pub val_size: usize,
}

#[derive(Debug, Default, Copy, Clone)]
pub enum ValueOperation {
    #[default]
    Read,
    Write(usize),
}

#[derive(Debug, Default, Clone)]
pub struct ValueArg {
    pub addr:      ValueAddr,
    pub operation: ValueOperation,
}

impl ValueArg {
    pub fn validate(&self) -> Result<(), ArgsError> {
        if let ValueOperation::Write(val) = self.operation {
            if val > (1 << (self.addr.val_size * 8)) {
                Err(ArgsError::ValLargerThanSize(val, self.addr.val_size))
            } else {
                Ok(())
            }
        } else {
            Ok(())
        }
    }

    pub fn to_string_with_val(&self, value: &UEFIValue) -> String {
        let var_name = &self.addr.var_name;
        let var_id_str = match self.addr.var_id {
            None => "".to_owned(),
            Some(id) => format!("({id})"),
        };

        let var_offset = self.addr.offset;
        let val_size_str = if self.addr.val_size == 1 {
            "".to_owned()
        } else {
            format!("({})", self.addr.val_size)
        };

        let value_str = value.to_string_with_size(self.addr.val_size);

        format!("{var_name}{var_id_str}:0x{var_offset:X}{val_size_str}={value_str}")
    }
}

#[derive(Debug, PartialEq, Copy, Clone)]
pub enum RebootMode {
    Never,
    Always,
    Auto,
}

impl Default for RebootMode {
    fn default() -> Self {
        Self::Never
    }
}

#[derive(Debug)]
pub enum NamedArg {
    Help,
    Reboot(RebootMode),
    WriteOnDemand,
}

#[derive(Debug)]
enum Arg {
    Named(NamedArg),
    Value(ValueArg),
}

#[derive(Debug, Default)]
pub struct Args {
    pub value_args:      Vec<ValueArg>,
    pub help_msg:        bool,
    pub write_on_demand: bool,
    pub reboot:          RebootMode,
}

impl Args {
    fn validate(&self) -> Result<(), ArgsError> {
        if self.help_msg {
            Ok(())
        } else {
            self.value_args.iter().try_for_each(|va| va.validate())
        }
    }
}

#[derive(Debug)]
pub enum ArgsError {
    ValLargerThanSize(usize, usize),
}

impl Display for ArgsError {
    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
        match self {
            Self::ValLargerThanSize(value, size) => {
                write!(
                    f,
                    "Specified value to write (0x{:0width$X}) is larger than specified size \
                     {size} bytes",
                    value,
                    width = size * 2,
                )
            }
        }
    }
}

impl From<ArgsError> for ParseError {
    fn from(value: ArgsError) -> Self {
        Self::InvalidArgs(value)
    }
}

pub const HELP_MSG: &str = r#"Usage:
setup_var.efi [-h/--help] [-r/--reboot(=auto)] [--write_on_demand] VALUE_ARG...

-r or --reboot: Reboot (warm reset) the computer after the program successfully finishes.
--reboot=auto: Reboot only if any value was actually written. This option automatically enables --write_on_demand.
--write_on_demand: If the value desired to be written is the same with storage, skip the unnecessary write.

VALUE_ARG represents the value needs to be read/written, and can be specified multiple times.
The format of VALUE_ARG is: <VAR_NAME>[(VAR_ID)]:<OFFSET>[(VALUE_SIZE)][=VALUE]

VAR_NAME: The name of UEFI variable to be altered, defaults to "Setup".
VAR_ID: Unique id for distinguishing variables with same name, which will be provided by setup_var.efi (when required).
OFFSET: The offset of value to be altered in the UEFI variable.
VALUE: The new value to write, capped at 64-bit. If not specified, the value at OFFSET will be read and shown.
VALUE_SIZE: Bytes of value to write, must be equal or larger than the size of <VALUE>, defaults to 1.

OFFSET, VALUE, VALUE_SIZE and VAR_ID are numbers, and can be specified in hexadecimal with prefix "0x", or decimal with no prefixes.

The program defaults to little endian for values ONLY while operating UEFI variables,
though it's recommended to only operate on one byte if you are not sure what this is or means.

Example: .\setup_var.efi -r CpuSetup:0x10E=0x1A"#;

pub fn parse_args() -> Result<Args, ParseError> {
    let loaded_image =
        uefi::boot::open_protocol_exclusive::<LoadedImage>(uefi::boot::image_handle())
            .map_err(|_| ParseError::LoadedImageProtocolError)?;

    let options = loaded_image
        .load_options_as_cstr16()
        .map_err(ParseError::LoadOptionsError)?;

    parse_args_from_str(options)
}

fn drop_first_arg(arg: &CStr16) -> bool {
    let rev_efi_ext: [Char16; 5] = [
        '.'.try_into().unwrap(),
        'e'.try_into().unwrap(),
        'f'.try_into().unwrap(),
        'i'.try_into().unwrap(),
        '\0'.try_into().unwrap(),
    ];
    let arg_chars = arg.as_slice_with_nul();
    let has_efi_ext = if arg_chars.len() < 5 {
        false
    } else {
        let arg_last_chars = &arg_chars[arg_chars.len() - 5..arg_chars.len()];
        arg_last_chars == rev_efi_ext
    };

    #[allow(clippy::needless_bool)]
    #[allow(clippy::if_same_then_else)]
    if has_efi_ext {
        true // efi extension, treated as the name of the executable file
    } else if starts_with(arg, '-') {
        false // Highly probably an option
    } else {
        // Now that we can't decide what is the first arg as they starts with the var
        // name, defaults to keep it
        false
    }
}

macro_rules! try_parsers {
    ($input:expr, $parser:expr) => {{
        $parser($input)
    }};

    ($input:expr, $parser:expr, $( $parsers:expr ),* $(,)? ) => {{
        if let Ok(val) = $parser($input) {
            Ok(val)
        } else {
            crate::args::try_parsers!($input, $($parsers),*)
        }
    }};
}

pub(crate) use try_parsers;

fn parse_args_from_str(options: &CStr16) -> Result<Args, ParseError> {
    let options = options.split_to_cstring(' '.try_into().unwrap());
    let opt_len = options.len();

    if opt_len == 0 {
        return Err(ParseError::NoArgs);
    }

    let first_arg = options[0].clone();
    let mut option_iter = options.into_iter();
    if drop_first_arg(&first_arg) {
        if opt_len == 1 {
            return Err(ParseError::NoArgs);
        }
        option_iter.next(); // Skips executable argv
    }

    let args = option_iter
        .filter(|s| s.as_slice_with_nul().len() != 1)
        .map(|s| {
            try_parsers!(&s, parse_named_arg, parse_value_arg_wrapped)
                .map_err(|e| ParseError::InvalidValue(format!("{s}: {e}")))
        })
        .collect::<Result<Vec<_>, _>>()?;

    let named_args = args
        .iter()
        .filter(|arg| matches!(arg, Arg::Named(_)))
        .map(|arg| {
            if let Arg::Named(arg) = arg {
                arg
            } else {
                unreachable!()
            }
        })
        .collect::<Vec<_>>();
    let value_args = args
        .iter()
        .filter(|arg| matches!(arg, Arg::Value(_)))
        .map(|arg| {
            if let Arg::Value(arg) = arg {
                arg.clone()
            } else {
                unreachable!()
            }
        })
        .collect::<Vec<_>>();

    let mut args = Args::default();
    for named_arg in named_args {
        match named_arg {
            NamedArg::Help => args.help_msg = true,
            NamedArg::Reboot(mode) => {
                args.reboot = *mode;
                if *mode == RebootMode::Auto {
                    args.write_on_demand = true;
                }
            }
            NamedArg::WriteOnDemand => args.write_on_demand = true,
        }
    }

    args.value_args = value_args;

    args.validate()?;
    Ok(args)
}

fn starts_with(s: &CStr16, c: char) -> bool {
    match s.as_slice_with_nul().first() {
        None => false,
        Some(&c_h) => c_h == Char16::try_from(c).unwrap(),
    }
}

fn try_next_char(iter: &mut impl Iterator<Item = char>, str: &CStr16) -> Result<char, ParseError> {
    iter.next()
        .ok_or_else(|| ParseError::InvalidValue(str.to_string()))
}

fn parse_hex_number(num_str: &CStr16) -> Result<usize, ParseError> {
    let mut str_iter = num_str.iter().map(|&c| char::from(c));

    // Prefix 0x(0X)
    let c_h = try_next_char(&mut str_iter, num_str)?;
    let c2_h = try_next_char(&mut str_iter, num_str)?;

    match (c_h, c2_h) {
        ('0', 'x') => {}
        ('0', 'X') => {}
        _ => return Err(ParseError::InvalidValue(num_str.to_string())),
    }

    if num_str.num_bytes() > 2 * (18 + 1) {
        return Err(ParseError::NumberTooLarge(num_str.to_string()));
    }

    let value = str_iter
        .map(|c| c.to_digit(16).map(|n| n as u8))
        .collect::<Option<Vec<u8>>>()
        .ok_or_else(|| ParseError::InvalidValue(num_str.to_string()))?;
    let value_len = value.len();
    let value = value.iter().enumerate().fold(0usize, |acc, (i, &n)| {
        acc + ((n as usize) << (4 * (value_len - i - 1)))
    });

    Ok(value)
}

fn parse_number(num_str: &CStr16) -> Result<usize, ParseError> {
    let chars = num_str.iter().map(|&c| char::from(c)).collect::<Vec<_>>();
    if chars.iter().any(|c| !c.is_ascii_digit()) {
        Err(ParseError::InvalidValue(num_str.to_string()))?
    }

    let value = chars
        .into_iter()
        .fold(0usize, |acc, n| acc * 10 + (n as u8 - b'0') as usize);

    Ok(value)
}

fn parse_named_arg(key: &CStr16) -> Result<Arg, ParseError> {
    if key.eq_str_until_nul(&"-h") || key.eq_str_until_nul(&"--help") {
        Ok(Arg::Named(NamedArg::Help))
    } else if key.eq_str_until_nul(&"-r=auto") || key.eq_str_until_nul(&"--reboot=auto") {
        Ok(Arg::Named(NamedArg::Reboot(RebootMode::Auto)))
    } else if key.eq_str_until_nul(&"-r") || key.eq_str_until_nul(&"--reboot") {
        Ok(Arg::Named(NamedArg::Reboot(RebootMode::Always)))
    } else if key.eq_str_until_nul(&"--write_on_demand") {
        Ok(Arg::Named(NamedArg::WriteOnDemand))
    } else {
        Err(ParseError::InvalidValue(key.to_string()))
    }
}

fn parse_value_arg_wrapped(arg: &CStr16) -> Result<Arg, ParseError> {
    Ok(Arg::Value(parse_value_arg(arg)?))
}

pub fn parse_value_wrapped(arg: &CStr16) -> Result<ValueOperation, ParseError> {
    Ok(parse_value(arg)?.1)
}

fn parse_value(arg: &CStr16) -> Result<(Cow<CStr16>, ValueOperation), ParseError> {
    if arg.contains('='.try_into().unwrap()) {
        let mut arg_split = arg.split_to_cstring('='.try_into().unwrap());
        if arg_split.len() != 2 {
            Err(ParseError::InvalidValue(arg.to_string()))?
        }
        let value = try_parsers!(&arg_split[1], parse_hex_number, parse_number)?;

        Ok((
            Cow::Owned(arg_split.swap_remove(0)),
            ValueOperation::Write(value),
        ))
    } else {
        Ok((Cow::Borrowed(arg), ValueOperation::Read))
    }
}

pub fn parse_value_arg(arg: &CStr16) -> Result<ValueArg, ParseError> {
    let mut arg_split = arg.split_to_cstring(':'.try_into().unwrap());
    if arg_split.len() != 2 {
        Err(ParseError::InvalidValue(arg.to_string()))?
    }

    let mut var_name = arg_split.swap_remove(0);
    let mut var_id = None;

    if var_name.contains('('.try_into().unwrap()) {
        let mut arg_split = var_name.split_to_cstring('('.try_into().unwrap());
        if arg_split.len() != 2 {
            Err(ParseError::InvalidValue(var_name.to_string()))?
        }
        let var_id_str = arg_split[1]
            .strip_suffix(')'.try_into().unwrap())
            .ok_or(ParseError::InvalidValue(var_name.to_string()))?;

        var_id = Some(try_parsers!(&var_id_str, parse_number, parse_hex_number)?);
        var_name = arg_split.swap_remove(0);
    }

    let var_offset = arg_split.swap_remove(0);
    let mut val_size = 1;

    let (mut var_offset, op_type) = parse_value(&var_offset)?;

    if var_offset.contains('('.try_into().unwrap()) {
        let mut arg_split = var_offset.split_to_cstring('('.try_into().unwrap());
        if arg_split.len() != 2 {
            Err(ParseError::InvalidValue(var_offset.to_string()))?
        }
        let val_size_str = arg_split[1]
            .strip_suffix(')'.try_into().unwrap())
            .ok_or(ParseError::InvalidValue(var_offset.to_string()))?;

        val_size = try_parsers!(&val_size_str, parse_number, parse_hex_number)?;
        var_offset = Cow::Owned(arg_split.swap_remove(0));
    }

    let offset = try_parsers!(&var_offset, parse_hex_number, parse_number)?;

    Ok(ValueArg {
        addr:      ValueAddr {
            var_name,
            var_id,
            offset,
            val_size,
        },
        operation: op_type,
    })
}

#[allow(dead_code)]
pub fn test_functions() {
    println!("Testing parse_hex_number");
    println!(
        r#"parse_hex_number("0x1"), should be Ok({}), result is {:?}"#,
        0x1,
        parse_hex_number(&CString16::try_from("0x1").unwrap())
    );
    println!(
        r#"parse_hex_number("0x01"), should be Ok({}), result is {:?}"#,
        0x1,
        parse_hex_number(&CString16::try_from("0x01").unwrap())
    );
    println!(
        r#"parse_hex_number("0X12e"), should be Ok({}), result is {:?}"#,
        0x12E,
        parse_hex_number(&CString16::try_from("0X12e").unwrap())
    );
    println!(
        r#"parse_hex_number("0x12eFAb"), should be Ok({}), result is {:?}"#,
        0x12EFAB,
        parse_hex_number(&CString16::try_from("0x12eFAb").unwrap())
    );
    println!(
        r#"parse_hex_number("0xDEADBEEFDEADBEEF01"), should be Err({}), result is {:?}"#,
        ParseError::NumberTooLarge("0xDEADBEEFDEADBEEF01".to_owned()),
        parse_hex_number(&CString16::try_from("0xDEADBEEFDEADBEEF01").unwrap())
    );
    println!(
        r#"parse_hex_number("0x12eFAs"), should be Err({:?}), result is {:?}"#,
        ParseError::InvalidValue("0x12eFAs".to_owned()),
        parse_hex_number(&CString16::try_from("0x12eFAs").unwrap())
    );
    println!(
        r#"parse_hex_number("abc"), should be Err({:?}), result is {:?}"#,
        ParseError::InvalidValue("abc".to_owned()),
        parse_hex_number(&CString16::try_from("abc").unwrap())
    );

    println!("Testing parse_named_arg");
    println!(
        r#"parse_named_arg("-h", None), should be Ok({:?}), result is {:?}"#,
        NamedArg::Help,
        parse_named_arg(&CString16::try_from("-h").unwrap())
    );
    println!(
        r#"parse_named_arg("-r", None), should be Ok({:?}), result is {:?}"#,
        NamedArg::Reboot(RebootMode::Always),
        parse_named_arg(&CString16::try_from("-r").unwrap())
    );
    println!(
        r#"parse_named_arg("--reboot", None), should be Ok({:?}), result is {:?}"#,
        NamedArg::Reboot(RebootMode::Always),
        parse_named_arg(&CString16::try_from("--reboot").unwrap())
    );
    println!(
        r#"parse_named_arg("--write_on_demand", None), should be Ok({:?}), result is {:?}"#,
        NamedArg::WriteOnDemand,
        parse_named_arg(&CString16::try_from("--write_on_demand").unwrap())
    );
    println!(
        r#"parse_named_arg("--help", Some("abc")), should be Ok({:?}), result is {:?}"#,
        NamedArg::Help,
        parse_named_arg(&CString16::try_from("--help").unwrap())
    );
    println!(
        r#"parse_named_arg("0x13", Some("CpuSetup")), should be Err({:?}), result is {:?}"#,
        ParseError::InvalidValue("0x13".to_owned()),
        parse_named_arg(&CString16::try_from("0x13").unwrap())
    );

    println!("Testing parse_value_arg");
    println!(
        r#"parse_value_arg("CpuSetup(2):0x19E"), should be Ok({:?}), result is {:?}"#,
        ValueArg {
            addr:      ValueAddr {
                var_name: CString16::try_from("CpuSetup").unwrap(),
                var_id:   Some(2),
                offset:   0x19E,
                val_size: 1,
            },
            operation: ValueOperation::Read,
        },
        parse_value_arg(&CString16::try_from("CpuSetup(2):0x19E").unwrap())
    );
    println!(
        r#"parse_value_arg("CpuSetup:0x19E(3)=0x02"), should be Ok({:?}), result is {:?}"#,
        ValueArg {
            addr:      ValueAddr {
                var_name: CString16::try_from("CpuSetup").unwrap(),
                var_id:   None,
                offset:   0x19E,
                val_size: 3,
            },
            operation: ValueOperation::Write(0x02),
        },
        parse_value_arg(&CString16::try_from("CpuSetup:0x19E(3)=0x02").unwrap())
    );

    println!("Testing parse_args_from_str");
    println!(
        r#"parse_args_from_str(".\setup_var.efi"), should be Ok({:?}), result is {:?}"#,
        Args {
            help_msg: true,
            ..Default::default()
        },
        parse_args_from_str(&CString16::try_from(".\\setup_var.efi").unwrap())
    );
    println!(
        r#"parse_args_from_str(".\setup_var.efi -h"), should be Ok({:?}), result is {:?}"#,
        Args {
            help_msg: true,
            ..Default::default()
        },
        parse_args_from_str(&CString16::try_from(".\\setup_var.efi -h").unwrap())
    );
    println!(
        r#"parse_args_from_str(".\setup_var.efi VAR:0x12 -h"), should be Ok({:?}), result is {:?}"#,
        Args {
            help_msg: true,
            value_args: vec![ValueArg {
                addr:      ValueAddr {
                    var_name: CString16::try_from("VAR").unwrap(),
                    var_id:   None,
                    offset:   0x12,
                    val_size: 1,
                },
                operation: ValueOperation::Read,
            },],
            ..Default::default()
        },
        parse_args_from_str(&CString16::try_from(".\\setup_var.efi VAR:0x12 -h").unwrap())
    );
    println!(
        r#"parse_args_from_str(".\setup_var.efi VAR:0x12=0x12 --write_on_demand -h"), should be Ok({:?}), result is {:?}"#,
        Args {
            help_msg: true,
            write_on_demand: true,
            value_args: vec![ValueArg {
                addr:      ValueAddr {
                    var_name: CString16::try_from("VAR").unwrap(),
                    var_id:   None,
                    offset:   0x12,
                    val_size: 1,
                },
                operation: ValueOperation::Write(0x12),
            },],
            ..Default::default()
        },
        parse_args_from_str(
            &CString16::try_from(".\\setup_var.efi VAR:0x12=0x12 --write_on_demand -h").unwrap()
        )
    );
    println!(
        r#"parse_args_from_str(".\setup_var.efi VAR:0x12=0x12e"), should be Err({:?}), result is {:?}"#,
        ParseError::InvalidArgs(ArgsError::ValLargerThanSize(0x12e, 1)),
        parse_args_from_str(&CString16::try_from(".\\setup_var.efi VAR:0x12=0x12e").unwrap())
    );
    println!(
        r#"parse_args_from_str(".\setup_var.efi VAR:0x01(3) VAR2(2):0x03=0x05"), should be Ok({:?}), result is {:?}"#,
        Args {
            value_args: vec![
                ValueArg {
                    addr:      ValueAddr {
                        var_name: CString16::try_from("VAR").unwrap(),
                        var_id:   None,
                        offset:   0x01,
                        val_size: 3,
                    },
                    operation: ValueOperation::Read,
                },
                ValueArg {
                    addr:      ValueAddr {
                        var_name: CString16::try_from("VAR2").unwrap(),
                        var_id:   Some(2),
                        offset:   0x03,
                        val_size: 1,
                    },
                    operation: ValueOperation::Write(0x05),
                }
            ],
            ..Default::default()
        },
        parse_args_from_str(
            &CString16::try_from(".\\setup_var.efi VAR:0x01(3) VAR2(2):0x03=0x05").unwrap()
        )
    );

    // Add new test for auto reboot mode
    println!(
        r#"parse_args_from_str(".\setup_var.efi --reboot=auto VAR:0x12=0x12"), should be Ok({:?}), result is {:?}"#,
        Args {
            help_msg:        false,
            write_on_demand: true, // auto reboot enables write_on_demand
            reboot:          RebootMode::Auto,
            value_args:      vec![ValueArg {
                addr:      ValueAddr {
                    var_name: CString16::try_from("VAR").unwrap(),
                    var_id:   None,
                    offset:   0x12,
                    val_size: 1,
                },
                operation: ValueOperation::Write(0x12),
            },],
        },
        parse_args_from_str(
            &CString16::try_from(".\\setup_var.efi --reboot=auto VAR:0x12=0x12").unwrap()
        )
    );
}


================================================
FILE: src/input.rs
================================================
use alloc::{
    borrow::{Cow, ToOwned},
    string::ToString,
    vec::Vec,
};

use uefi::{
    CStr16, CString16,
    data_types::EqStrUntilNul,
    proto::console::text::{Input, Key},
    system::with_stdin,
};

use crate::{
    args::{Args, NamedArg, ParseError, RebootMode, ValueAddr, ValueArg, ValueOperation},
    utils::CStr16Ext,
};

fn read_to_string(stdin: &mut Input) -> uefi::Result<CString16> {
    let mut str = CString16::new();

    while let Some(key) = stdin.read_key()? {
        if let Key::Printable(char) = key {
            str.push(char)
        }
    }

    Ok(str)
}

pub fn parse_input() -> Result<Args, ParseError> {
    let content = with_stdin(read_to_string).map_err(|_| ParseError::LoadStdInError)?;
    if content.is_empty() {
        return Err(ParseError::NoInput);
    }
    let content = content
        .strip_prefix('\u{feff}'.try_into().unwrap())
        .unwrap_or(&content);

    let lines = content.split_to_cstring('\n'.try_into().unwrap());
    let lines = lines.into_iter().filter_map(|s| {
        let s = s.trim();
        if s.starts_with('#'.try_into().unwrap()) {
            return None;
        }

        let res = s.strip_suffix('\r'.try_into().unwrap()).unwrap_or(s);
        if res.is_empty() { None } else { Some(res) }
    });

    let entries = lines
        .map(|s| {
            crate::args::try_parsers!(
                &s,
                parser_with_comment(parse_named_arg),
                parser_with_comment(parse_address_def),
                parser_with_comment(parse_value_arg_wrapped),
                parser_with_comment(parse_address_ref),
            )
        })
        .collect::<Result<Vec<_>, _>>()?;

    let address_defs = entries
        .iter()
        .filter(|e| matches!(e, FileInputEntry::AddressDef { .. }))
        .map(|e| e.as_address_def())
        .collect::<Vec<_>>();
    let mut val_args = entries
        .iter()
        .filter(|e| matches!(e, FileInputEntry::ValueArg(_)))
        .map(|e| e.as_value_arg())
        .cloned()
        .collect::<Vec<_>>();

    let address_refs = entries
        .iter()
        .filter(|e| matches!(e, FileInputEntry::AddressRef { .. }));
    let mut address_ref_args = address_refs
        .map(|e| match e {
            FileInputEntry::AddressRef { name, operation } => {
                let (_, addr) = address_defs
                    .iter()
                    .find(|(def_name, _)| name == *def_name)
                    .ok_or_else(|| ParseError::InvalidValue(name.to_string()))?;
                Ok(ValueArg {
                    addr:      (*addr).clone(),
                    operation: *operation,
                })
            }
            _ => unreachable!(),
        })
        .collect::<Result<Vec<_>, ParseError>>()?;

    val_args.append(&mut address_ref_args);

    // Here we choose to let the last occurred setting override previous ones
    let reboot_entry = entries
        .iter()
        .filter(|e| matches!(e, FileInputEntry::NamedArg(NamedArg::Reboot(_))))
        .next_back();
    let reboot = match reboot_entry {
        Some(FileInputEntry::NamedArg(NamedArg::Reboot(mode))) => *mode,
        _ => RebootMode::Never,
    };

    let write_on_demand = entries
        .iter()
        .any(|e| matches!(e, FileInputEntry::NamedArg(NamedArg::WriteOnDemand)));

    Ok(Args {
        value_args: val_args,
        help_msg: false,
        write_on_demand,
        reboot,
    })
}

enum FileInputEntry {
    AddressDef {
        name: CString16,
        addr: ValueAddr,
    },
    ValueArg(ValueArg),
    AddressRef {
        name:      CString16,
        operation: ValueOperation,
    },
    NamedArg(NamedArg),
}

impl FileInputEntry {
    fn as_address_def(&self) -> (&CString16, &ValueAddr) {
        match self {
            Self::AddressDef { name, addr } => (name, addr),
            _ => panic!("Invalid variant used on into_address_def"),
        }
    }

    fn as_value_arg(&self) -> &ValueArg {
        match self {
            Self::ValueArg(val_arg) => val_arg,
            _ => panic!("Invalid variant used on into_value_arg"),
        }
    }
}

fn parser_with_comment<T>(parser: T) -> impl Fn(&CStr16) -> Result<FileInputEntry, ParseError>
where
    T: Fn(&CStr16) -> Result<FileInputEntry, ParseError>,
{
    move |arg| {
        let arg = if let Some((arg, _comment)) = arg.split_only_first('#'.try_into().unwrap()) {
            Cow::Owned(arg.trim())
        } else {
            Cow::Borrowed(arg)
        };

        parser(&arg)
    }
}

fn parse_named_arg(arg: &CStr16) -> Result<FileInputEntry, ParseError> {
    let named_arg = arg
        .strip_prefix('@'.try_into().unwrap())
        .ok_or_else(|| ParseError::InvalidValue(arg.to_string()))?;

    if named_arg.eq_str_until_nul("reboot=auto") {
        Ok(FileInputEntry::NamedArg(NamedArg::Reboot(RebootMode::Auto)))
    } else if named_arg.eq_str_until_nul("reboot") {
        Ok(FileInputEntry::NamedArg(NamedArg::Reboot(
            RebootMode::Always,
        )))
    } else if named_arg.eq_str_until_nul("write_on_demand") {
        Ok(FileInputEntry::NamedArg(NamedArg::WriteOnDemand))
    } else {
        Err(ParseError::InvalidValue(arg.to_string()))
    }
}

fn parse_address_def(arg: &CStr16) -> Result<FileInputEntry, ParseError> {
    let (addr_name, addr_def) = arg
        .split_only_first('='.try_into().unwrap())
        .ok_or_else(|| ParseError::InvalidValue(arg.to_string()))?;

    let addr_name = addr_name
        .strip_suffix(':'.try_into().unwrap())
        .ok_or_else(|| ParseError::InvalidValue(arg.to_string()))?;
    let val_arg = crate::args::parse_value_arg(&addr_def)?;

    if let ValueOperation::Write(_) = val_arg.operation {
        Err(ParseError::AddrDefWrite(addr_def.to_string()))
    } else {
        Ok(FileInputEntry::AddressDef {
            name: addr_name,
            addr: val_arg.addr,
        })
    }
}

fn parse_value_arg_wrapped(arg: &CStr16) -> Result<FileInputEntry, ParseError> {
    Ok(FileInputEntry::ValueArg(crate::args::parse_value_arg(arg)?))
}

fn parse_address_ref(arg: &CStr16) -> Result<FileInputEntry, ParseError> {
    let (addr_name, _value_str) = arg
        .split_only_first('='.try_into().unwrap())
        .ok_or_else(|| ParseError::InvalidValue(arg.to_string()))?;

    let addr_name = if addr_name.starts_with('$'.try_into().unwrap()) {
        addr_name
            .strip_prefix('$'.try_into().unwrap())
            .ok_or_else(|| ParseError::InvalidValue(arg.to_string()))?
    } else {
        Err(ParseError::InvalidValue(addr_name.to_string()))?
    };

    let value_op = crate::args::parse_value_wrapped(arg)?;

    Ok(FileInputEntry::AddressRef {
        name:      addr_name.to_owned(),
        operation: value_op,
    })
}


================================================
FILE: src/main.rs
================================================
#![no_main]
#![no_std]

extern crate alloc;

mod args;
mod input;
mod utils;

use args::{HELP_MSG, ParseError, RebootMode, ValueArg, ValueOperation};
use uefi::{prelude::*, println, runtime::ResetType};
use utils::{UEFIValue, WriteStatus};

use crate::input::parse_input;

#[entry]
fn main() -> Status {
    uefi::helpers::init().expect("Unexpected error while initializing UEFI services");

    let args = match args::parse_args() {
        Ok(args) => {
            if args.help_msg {
                println!("{}", HELP_MSG);
                return Status::INVALID_PARAMETER;
            }

            args
        }
        Err(ParseError::NoArgs) => match parse_input() {
            Ok(args) => args,
            Err(ParseError::NoInput) => {
                println!("{}", HELP_MSG);
                return Status::INVALID_PARAMETER;
            }
            Err(e) => {
                println!("Error parsing input file:\n{e}");
                return Status::INVALID_PARAMETER;
            }
        },
        Err(e) => {
            println!("Error parsing arguments:\n{e}");
            return Status::INVALID_PARAMETER;
        }
    };

    let mut arg_process_state = ArgProcessState::default();
    for val_arg in args.value_args {
        let (status, state) = process_arg(args.write_on_demand, &val_arg);

        if status != Status::SUCCESS {
            return status;
        }
        arg_process_state.bind(&state);
    }

    let reboot_required = matches!(arg_process_state.write_status, WriteStatus::Normal);
    if args.reboot == RebootMode::Always || (args.reboot == RebootMode::Auto && reboot_required) {
        runtime::reset(ResetType::WARM, Status::SUCCESS, None);
    }

    Status::SUCCESS
}

struct ArgProcessState {
    write_status: WriteStatus,
}

impl ArgProcessState {
    fn bind(&mut self, other: &Self) {
        if let WriteStatus::Skipped = self.write_status {
            if let WriteStatus::Normal = other.write_status {
                self.write_status = WriteStatus::Normal;
            }
        }
    }

    fn nothing_written() -> Self {
        Self {
            write_status: WriteStatus::Skipped,
        }
    }
}

impl Default for ArgProcessState {
    fn default() -> Self {
        Self::nothing_written()
    }
}

fn process_arg(write_on_demand: bool, val_arg: &ValueArg) -> (Status, ArgProcessState) {
    let var_name = &val_arg.addr.var_name;
    let val_size = val_arg.addr.val_size;
    let offset = val_arg.addr.offset;

    match val_arg.operation {
        ValueOperation::Read => {
            match utils::read_val(var_name, val_arg.addr.var_id, offset, val_size) {
                Ok(value) => {
                    println!("{}", val_arg.to_string_with_val(&value));
                    (Status::SUCCESS, ArgProcessState::nothing_written())
                }
                Err(e) => {
                    println!("Error reading variable:\n{e}");
                    (Status::ABORTED, ArgProcessState::nothing_written())
                }
            }
        }
        ValueOperation::Write(value) => {
            let value = UEFIValue::from_usize(value, val_size);

            match utils::write_val(
                var_name,
                val_arg.addr.var_id,
                offset,
                &value,
                val_size,
                write_on_demand,
            ) {
                Err(e) => {
                    println!("Error writing variable:\n{e}");
                    (Status::ABORTED, ArgProcessState::nothing_written())
                }
                Ok(write_status) => {
                    let skipped_msg = match write_status {
                        WriteStatus::Skipped => " # Writing skipped",
                        WriteStatus::Normal => "",
                    };

                    println!("{}{}", val_arg.to_string_with_val(&value), skipped_msg);
                    (Status::SUCCESS, ArgProcessState { write_status })
                }
            }
        }
    }
}


================================================
FILE: src/utils.rs
================================================
use alloc::{
    borrow::ToOwned,
    format,
    string::{String, ToString},
    vec,
    vec::Vec,
};
use core::fmt::{Display, Formatter};

use num_enum::TryFromPrimitive;
use strum::EnumMessage;
use uefi::{
    CStr16, CString16, Char16, ResultExt, Status,
    data_types::{FromSliceWithNulError, chars::NUL_16},
    print, println,
    runtime::{VariableAttributes, VariableKey, VariableVendor},
};

#[allow(non_camel_case_types, clippy::upper_case_acronyms)]
#[derive(TryFromPrimitive, EnumMessage, strum::Display)]
#[repr(u8)]
pub enum UEFIStatusErrorCode {
    /// The image failed to load.
    LOAD_ERROR           = 1,
    /// A parameter was incorrect.
    INVALID_PARAMETER    = 2,
    /// The operation is not supported.
    UNSUPPORTED          = 3,
    /// The buffer was not the proper size for the request.
    BAD_BUFFER_SIZE      = 4,
    /// The buffer is not large enough to hold the requested data.
    /// The required buffer size is returned in the appropriate parameter.
    BUFFER_TOO_SMALL     = 5,
    /// There is no data pending upon return.
    NOT_READY            = 6,
    /// The physical device reported an error while attempting the operation.
    DEVICE_ERROR         = 7,
    /// The device cannot be written to.
    WRITE_PROTECTED      = 8,
    /// A resource has run out.
    OUT_OF_RESOURCES     = 9,
    /// An inconstency was detected on the file system.
    VOLUME_CORRUPTED     = 10,
    /// There is no more space on the file system.
    VOLUME_FULL          = 11,
    /// The device does not contain any medium to perform the operation.
    NO_MEDIA             = 12,
    /// The medium in the device has changed since the last access.
    MEDIA_CHANGED        = 13,
    /// The item was not found.
    NOT_FOUND            = 14,
    /// Access was denied.
    ACCESS_DENIED        = 15,
    /// The server was not found or did not respond to the request.
    NO_RESPONSE          = 16,
    /// A mapping to a device does not exist.
    NO_MAPPING           = 17,
    /// The timeout time expired.
    TIMEOUT              = 18,
    /// The protocol has not been started.
    NOT_STARTED          = 19,
    /// The protocol has already been started.
    ALREADY_STARTED      = 20,
    /// The operation was aborted.
    ABORTED              = 21,
    /// An ICMP error occurred during the network operation.
    ICMP_ERROR           = 22,
    /// A TFTP error occurred during the network operation.
    TFTP_ERROR           = 23,
    /// A protocol error occurred during the network operation.
    PROTOCOL_ERROR       = 24,
    /// The function encountered an internal version that was
    /// incompatible with a version requested by the caller.
    INCOMPATIBLE_VERSION = 25,
    /// The function was not performed due to a security violation.
    SECURITY_VIOLATION   = 26,
    /// A CRC error was detected.
    CRC_ERROR            = 27,
    /// Beginning or end of media was reached
    END_OF_MEDIA         = 28,
    /// The end of the file was reached.
    END_OF_FILE          = 31,
    /// The language specified was invalid.
    INVALID_LANGUAGE     = 32,
    /// The security status of the data is unknown or compromised and
    /// the data must be updated or replaced to restore a valid security status.
    COMPROMISED_DATA     = 33,
    /// There is an address conflict address allocation
    IP_ADDRESS_CONFLICT  = 34,
    /// A HTTP error occurred during the network operation.
    HTTP_ERROR           = 35,
}

pub enum UEFIStatusError {
    Success,
    Error(UEFIStatusErrorCode),
    UnknownError(usize),
}

impl From<Status> for UEFIStatusError {
    fn from(value: Status) -> Self {
        if !value.is_error() {
            Self::Success
        } else {
            match UEFIStatusErrorCode::try_from(value.0 as u8) {
                Ok(error_code) => UEFIStatusError::Error(error_code),
                Err(_) => UEFIStatusError::UnknownError(value.0),
            }
        }
    }
}

impl Display for UEFIStatusError {
    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
        match self {
            UEFIStatusError::Success => write!(f, "Success"),
            UEFIStatusError::Error(error_code) => {
                write!(
                    f,
                    "{} ({})",
                    error_code,
                    error_code.get_documentation().unwrap_or_default()
                )
            }
            UEFIStatusError::UnknownError(code) => write!(f, "Unknown error with code {}", code),
        }
    }
}

pub enum UEFIVarError {
    NoCorrespondingVar,
    MultipleVarNoId,
    InvalidVarName(FromSliceWithNulError),
    GetVariableSize(String, UEFIStatusError),
    GetVariable(String, UEFIStatusError),
    OffsetOverflow((usize, usize), usize), // ((offset, val_size), var_size)
    SetVariable(String, UEFIStatusError),
}

impl Display for UEFIVarError {
    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
        match self {
            Self::NoCorrespondingVar => {
                write!(f, "No variable with specified name found")
            }
            Self::MultipleVarNoId => {
                write!(
                    f,
                    "Please re-run with variable id as shown in the above table"
                )
            }
            Self::InvalidVarName(e) => {
                write!(f, "Unexpected invalid UEFI variable name obtained: {e:?}")
            }
            Self::GetVariableSize(s, st) => {
                write!(f, "Error while getting size of variable {s}: {st}")
            }
            Self::GetVariable(s, st) => {
                write!(f, "Error while getting content of variable {s}: {st}",)
            }
            Self::OffsetOverflow((offset, val_size), size) => {
                write!(
                    f,
                    "Specified offset 0x{offset:X} and value size 0x{val_size:X} exceeds variable \
                     size 0x{size:X}"
                )
            }
            Self::SetVariable(s, st) => {
                write!(f, "Error while setting content of variable {s}: {st}")
            }
        }
    }
}

impl From<FromSliceWithNulError> for UEFIVarError {
    fn from(value: FromSliceWithNulError) -> Self {
        Self::InvalidVarName(value)
    }
}

struct UEFIVariable {
    name:       CString16,
    vendor:     VariableVendor,
    attributes: VariableAttributes,
    content:    Vec<u8>,
}

pub struct UEFIValue(pub Vec<u8>);

impl UEFIValue {
    pub fn from_usize(value: usize, val_size: usize) -> Self {
        let value = value & ((1 << (val_size * 8)) - 1);
        Self(value.to_le_bytes()[0..val_size].to_vec())
    }

    pub fn to_string_with_size(&self, val_size: usize) -> String {
        let mut bytes = [0; 8];
        bytes[0..self.0.len()].copy_from_slice(&self.0);

        format!(
            "0x{:0width$X}",
            usize::from_ne_bytes(bytes),
            width = val_size * 2
        )
    }
}

impl Display for UEFIValue {
    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
        let mut bytes = [0; 8];
        bytes[0..self.0.len()].copy_from_slice(&self.0);

        write!(f, "0x{:X}", usize::from_ne_bytes(bytes))
    }
}

pub fn read_val(
    var_name: &CStr16,
    var_id: Option<usize>,
    offset: usize,
    val_size: usize,
) -> Result<UEFIValue, UEFIVarError> {
    let var = read_var(var_name, var_id)?;
    if offset + val_size > var.content.len() {
        return Err(UEFIVarError::OffsetOverflow(
            (offset, val_size),
            var.content.len(),
        ));
    }

    let slice = &var.content[offset..offset + val_size];
    Ok(UEFIValue(slice.to_vec()))
}

pub enum WriteStatus {
    Normal,
    Skipped,
}

pub fn write_val(
    var_name: &CStr16,
    var_id: Option<usize>,
    offset: usize,
    value: &UEFIValue,
    val_size: usize,
    write_on_demand: bool,
) -> Result<WriteStatus, UEFIVarError> {
    let mut var = read_var(var_name, var_id)?;
    if offset + val_size > var.content.len() {
        return Err(UEFIVarError::OffsetOverflow(
            (offset, val_size),
            var.content.len(),
        ));
    }

    let slice = &mut var.content[offset..offset + val_size];

    if write_on_demand && slice == value.0 {
        Ok(WriteStatus::Skipped)
    } else {
        slice.copy_from_slice(&value.0);

        uefi::runtime::set_variable(&var.name, &var.vendor, var.attributes, &var.content)
            .map_err(|e| UEFIVarError::SetVariable(var.name.to_string(), e.status().into()))?;

        Ok(WriteStatus::Normal)
    }
}

fn read_var(var_name: &CStr16, var_id: Option<usize>) -> Result<UEFIVariable, UEFIVarError> {
    let keys = uefi::runtime::variable_keys();
    let mut keys = keys
        .into_iter()
        .filter_map(|k| k.ok())
        .filter(|k| k.name == var_name)
        .collect::<Vec<_>>();
    keys.sort_by_key(|k| k.vendor.0);

    if keys.is_empty() {
        return Err(UEFIVarError::NoCorrespondingVar);
    }

    if keys.len() > 1 && var_id.is_none() {
        print_keys(keys)?;
        return Err(UEFIVarError::MultipleVarNoId);
    }

    let var_key = if keys.len() == 1 {
        &keys[0]
    } else {
        &keys[var_id.unwrap()] // if keys.len() == 1, then branch above; if keys.len() > 1 && var_id is None, then above if
    };
    let var_name = &var_key.name;

    let size = get_variable_size(var_name, &var_key.vendor)
        .map_err(|e| UEFIVarError::GetVariableSize(var_name.to_string(), e.status().into()))?;
    let mut buf = vec![0; size];
    let (_, var_attr) = uefi::runtime::get_variable(var_name, &var_key.vendor, &mut buf)
        .map_err(|e| UEFIVarError::GetVariable(var_name.to_string(), e.status().into()))?;

    Ok(UEFIVariable {
        name:       var_name.to_owned(),
        vendor:     var_key.vendor,
        attributes: var_attr,
        content:    buf,
    })
}

fn print_keys(keys: Vec<VariableKey>) -> Result<(), UEFIVarError> {
    println!("Multiple variables with same name detected:");
    println!("ID\tVarName\t\t\t\tSize\t");
    println!();

    for (i, key) in keys.into_iter().enumerate() {
        let id = i;
        let name = &key.name;
        let size = get_variable_size(name, &key.vendor)
            .map_err(|e| UEFIVarError::GetVariableSize(name.to_string(), e.status().into()))?;
        print!("0x{:X}\t", id);
        print!("{name}");
        match (name.num_bytes() / 2 - 1) / 8 {
            0 => {
                print!("\t\t\t\t")
            }
            1 => {
                print!("\t\t\t")
            }
            2 => {
                print!("\t\t")
            }
            _ => {
                print!("\t")
            }
        }
        println!("0x{:X}\t", size)
    }

    Ok(())
}

fn get_variable_size(name: &CStr16, vendor: &VariableVendor) -> uefi::Result<usize> {
    let res = uefi::runtime::get_variable(name, vendor, &mut []);
    if res.status() == Status::BUFFER_TOO_SMALL {
        let err = res.unwrap_err();
        Ok(err.data().unwrap_or_default())
    } else {
        Err(res.discard_errdata().unwrap_err())
    }
}

pub trait CStr16Ext {
    fn contains(&self, char: Char16) -> bool;
    fn strip_prefix(&self, prefix: Char16) -> Option<&CStr16>;
    fn strip_suffix(&self, suffix: Char16) -> Option<CString16>;
    /// The CStr16 requires a NUL terminator, so we can only collect them back
    /// into CString16
    fn split_to_cstring(&self, split: Char16) -> Vec<CString16>;
    fn split_only_first(&self, split: Char16) -> Option<(CString16, CString16)>;
    fn trim(&self) -> CString16;
    fn starts_with(&self, char: Char16) -> bool;
}

impl CStr16Ext for CStr16 {
    fn contains(&self, char: Char16) -> bool {
        self.iter().any(|&c| c == char)
    }

    fn strip_prefix(&self, prefix: Char16) -> Option<&CStr16> {
        if *self.iter().next()? == prefix {
            let str_ref = unsafe {
                CStr16::from_u16_with_nul_unchecked(
                    &*(&self.as_slice_with_nul()[1..] as *const [Char16] as *const [u16]),
                )
            };
            Some(str_ref)
        } else {
            None
        }
    }

    fn strip_suffix(&self, suffix: Char16) -> Option<CString16> {
        let str = self.to_u16_slice();
        if *str.last()? == u16::from(suffix) {
            let mut buf = self
                .as_slice()
                .iter()
                .map(|&c| u16::from(c))
                .collect::<Vec<_>>();
            *buf.last_mut()? = 0;
            Some(CString16::try_from(buf).unwrap())
        } else {
            None
        }
    }

    fn split_to_cstring(&self, split: Char16) -> Vec<CString16> {
        let mut split_strings = Vec::new();
        let mut current_string = Vec::new();

        for c in self.iter() {
            if *c != split {
                current_string.push(u16::from(*c))
            } else {
                current_string.push(0u16);
                split_strings.push(
                    current_string
                        .try_into()
                        .expect("Invalid bytes in arguments"),
                );
                current_string = Vec::new()
            }
        }

        if !current_string.is_empty() {
            current_string.push(0u16);
            split_strings.push(
                current_string
                    .try_into()
                    .expect("Invalid bytes in arguments"),
            )
        }

        split_strings
    }

    fn split_only_first(&self, split: Char16) -> Option<(CString16, CString16)> {
        let index = self.iter().position(|&c| c == split)?;

        // We have to copy twice and check validity again???
        let mut first_str = self.as_slice()[..index].to_vec();
        first_str.push(NUL_16);

        let mut second_str = self.as_slice()[index + 1..].to_vec();
        second_str.push(NUL_16);

        let first_str = char16_vec_to_cstring16(first_str);
        let second_str = char16_vec_to_cstring16(second_str);

        Some((first_str, second_str))
    }

    fn trim(&self) -> CString16 {
        let is_space =
            |&c| c == Char16::try_from(' ').unwrap() || c == Char16::try_from('\t').unwrap();

        let mut start = 0;
        for (i, c) in self.iter().enumerate() {
            if !is_space(c) {
                start = i;
                break;
            }
        }

        let mut end = self.num_chars() - 1;
        for (i, c) in self.as_slice().iter().rev().enumerate() {
            if !is_space(c) {
                end -= i;
                break;
            }
        }

        let mut str = self.as_slice()[start..=end].to_vec();
        str.push(NUL_16);

        char16_vec_to_cstring16(str)
    }

    fn starts_with(&self, char: Char16) -> bool {
        *self.iter().next().unwrap_or(&NUL_16) == char
    }
}

/// We have no way to directly construct CString16, and as it does NOT use
/// repr(transparent). We even cannot construct it with unsafe operations. A
/// copy and char validity check is required in this function.
fn char16_vec_to_cstring16(s: Vec<Char16>) -> CString16 {
    CString16::try_from(s.into_iter().map(u16::from).collect::<Vec<_>>()).unwrap()
}