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| 1 | +// SPDX-License-Identifier: MIT OR Apache-2.0 |
| 2 | + |
| 3 | +//! UEFI Configuration String parsing according to Spec 35.2.1 |
| 4 | + |
| 5 | +use alloc::boxed::Box; |
| 6 | +use alloc::string::{String, ToString}; |
| 7 | +use alloc::vec::Vec; |
| 8 | +use core::slice; |
| 9 | +use core::str::{self, FromStr}; |
| 10 | +use uguid::Guid; |
| 11 | + |
| 12 | +use crate::proto::device_path::DevicePath; |
| 13 | +use crate::{CStr16, Char16}; |
| 14 | + |
| 15 | +/// A helper struct to split and parse a UEFI Configuration String. |
| 16 | +/// |
| 17 | +/// Configuration strings consist of key-value pairs separated by `&`. Keys |
| 18 | +/// and values are separated by `=`. This struct provides an iterator for |
| 19 | +/// easy traversal of the key-value pairs. |
| 20 | +/// |
| 21 | +/// For reasons of developer sanity, this is operating on &str instead of &CStr16. |
| 22 | +#[derive(Debug)] |
| 23 | +pub struct ConfigurationStringIter<'a> { |
| 24 | + bfr: &'a str, |
| 25 | +} |
| 26 | + |
| 27 | +impl<'a> ConfigurationStringIter<'a> { |
| 28 | + /// Creates a new splitter instance for a given configuration string buffer. |
| 29 | + #[must_use] |
| 30 | + pub const fn new(bfr: &'a str) -> Self { |
| 31 | + Self { bfr } |
| 32 | + } |
| 33 | +} |
| 34 | + |
| 35 | +impl<'a> Iterator for ConfigurationStringIter<'a> { |
| 36 | + type Item = (&'a str, Option<&'a str>); |
| 37 | + |
| 38 | + fn next(&mut self) -> Option<Self::Item> { |
| 39 | + if self.bfr.is_empty() { |
| 40 | + return None; |
| 41 | + } |
| 42 | + let (keyval, remainder) = self |
| 43 | + .bfr |
| 44 | + .split_once('&') |
| 45 | + .unwrap_or((self.bfr, &self.bfr[0..0])); |
| 46 | + self.bfr = remainder; |
| 47 | + let (key, value) = keyval |
| 48 | + .split_once('=') |
| 49 | + .map(|(key, value)| (key, Some(value))) |
| 50 | + .unwrap_or((keyval, None)); |
| 51 | + Some((key, value)) |
| 52 | + } |
| 53 | +} |
| 54 | + |
| 55 | +/// Enum representing different sections of a UEFI Configuration Header. |
| 56 | +/// |
| 57 | +/// These sections include GUID, Name, and Path elements, which provide |
| 58 | +/// routing and identification information for UEFI components. |
| 59 | +#[derive(Debug, PartialEq, Eq)] |
| 60 | +pub enum ConfigHdrSection { |
| 61 | + /// UEFI ConfigurationString {GuidHdr} element |
| 62 | + Guid, |
| 63 | + /// UEFI ConfigurationString {NameHdr} element |
| 64 | + Name, |
| 65 | + /// UEFI ConfigurationString {PathHdr} element |
| 66 | + Path, |
| 67 | +} |
| 68 | + |
| 69 | +/// Enum representing possible parsing errors encountered when processing |
| 70 | +/// UEFI Configuration Strings. |
| 71 | +#[derive(Debug)] |
| 72 | +pub enum ParseError { |
| 73 | + /// Error while parsing the UEFI {ConfigHdr} configuration string section. |
| 74 | + ConfigHdr(ConfigHdrSection), |
| 75 | + /// Error while parsing the UEFI {BlockName} configuration string section. |
| 76 | + BlockName, |
| 77 | + /// Error while parsing the UEFI {BlockConfig} configuration string section. |
| 78 | + BlockConfig, |
| 79 | +} |
| 80 | + |
| 81 | +/// Represents an individual element within a UEFI Configuration String. |
| 82 | +/// |
| 83 | +/// Each element contains an offset, width, and value, defining the data |
| 84 | +/// stored at specific memory locations within the configuration. |
| 85 | +#[derive(Debug, Default)] |
| 86 | +pub struct ConfigurationStringElement { |
| 87 | + /// Byte offset in the configuration block |
| 88 | + pub offset: u64, |
| 89 | + /// Length of the value starting at offset |
| 90 | + pub width: u64, |
| 91 | + /// Value bytes |
| 92 | + pub value: Vec<u8>, |
| 93 | + // TODO |
| 94 | + // nvconfig: HashMap<String, Vec<u8>>, |
| 95 | +} |
| 96 | + |
| 97 | +/// A full UEFI Configuration String representation. |
| 98 | +/// |
| 99 | +/// This structure contains routing information such as GUID and device path, |
| 100 | +/// along with the parsed configuration elements. |
| 101 | +#[derive(Debug)] |
| 102 | +pub struct ConfigurationString { |
| 103 | + /// GUID used for identifying the configuration |
| 104 | + pub guid: Guid, |
| 105 | + /// Name field (optional identifier) |
| 106 | + pub name: String, |
| 107 | + /// Associated UEFI device path |
| 108 | + pub device_path: Box<DevicePath>, |
| 109 | + /// Parsed UEFI {ConfigElement} sections |
| 110 | + pub elements: Vec<ConfigurationStringElement>, |
| 111 | +} |
| 112 | + |
| 113 | +impl ConfigurationString { |
| 114 | + fn try_parse_with<T, F: FnOnce() -> Option<T>>( |
| 115 | + err: ParseError, |
| 116 | + parse_fn: F, |
| 117 | + ) -> Result<T, ParseError> { |
| 118 | + parse_fn().ok_or(err) |
| 119 | + } |
| 120 | + |
| 121 | + /// Parses a hexadecimal string into an iterator of bytes. |
| 122 | + /// |
| 123 | + /// # Arguments |
| 124 | + /// |
| 125 | + /// * `hex` - The hexadecimal string representing binary data. |
| 126 | + /// |
| 127 | + /// # Returns |
| 128 | + /// |
| 129 | + /// An iterator over bytes. |
| 130 | + pub fn parse_bytes_from_hex(hex: &str) -> impl Iterator<Item = u8> { |
| 131 | + hex.as_bytes().chunks(2).map(|chunk| { |
| 132 | + let chunk = str::from_utf8(chunk).unwrap_or_default(); |
| 133 | + u8::from_str_radix(chunk, 16).unwrap_or_default() |
| 134 | + }) |
| 135 | + } |
| 136 | + |
| 137 | + /// Converts a hexadecimal string representation into a numeric value. |
| 138 | + /// |
| 139 | + /// # Arguments |
| 140 | + /// |
| 141 | + /// * `data` - The hexadecimal string to convert. |
| 142 | + /// |
| 143 | + /// # Returns |
| 144 | + /// |
| 145 | + /// An `Option<u64>` representing the parsed number. |
| 146 | + #[must_use] |
| 147 | + pub fn parse_number_from_hex(data: &str) -> Option<u64> { |
| 148 | + let data: Vec<_> = Self::parse_bytes_from_hex(data).collect(); |
| 149 | + match data.len() { |
| 150 | + 8 => Some(u64::from_be_bytes(data.try_into().unwrap())), |
| 151 | + 4 => Some(u32::from_be_bytes(data.try_into().unwrap()) as u64), |
| 152 | + 2 => Some(u16::from_be_bytes(data.try_into().unwrap()) as u64), |
| 153 | + 1 => Some(u8::from_be_bytes(data.try_into().unwrap()) as u64), |
| 154 | + _ => None, |
| 155 | + } |
| 156 | + } |
| 157 | + |
| 158 | + /// Converts a hexadecimal string into a UTF-16 string. |
| 159 | + /// |
| 160 | + /// # Arguments |
| 161 | + /// |
| 162 | + /// * `data` - The hexadecimal representation of a string. |
| 163 | + /// |
| 164 | + /// # Returns |
| 165 | + /// |
| 166 | + /// An `Option<String>` containing the parsed string. |
| 167 | + #[must_use] |
| 168 | + pub fn parse_string_from_hex(data: &str) -> Option<String> { |
| 169 | + if data.len() % 2 != 0 { |
| 170 | + return None; |
| 171 | + } |
| 172 | + let mut data: Vec<_> = Self::parse_bytes_from_hex(data).collect(); |
| 173 | + data.chunks_exact_mut(2).for_each(|c| c.swap(0, 1)); |
| 174 | + data.extend_from_slice(&[0, 0]); |
| 175 | + let data: &[Char16] = |
| 176 | + unsafe { slice::from_raw_parts(data.as_slice().as_ptr().cast(), data.len() / 2) }; |
| 177 | + Some(CStr16::from_char16_with_nul(data).ok()?.to_string()) |
| 178 | + } |
| 179 | + |
| 180 | + /// Parses a hexadecimal string into a UEFI GUID. |
| 181 | + /// |
| 182 | + /// # Arguments |
| 183 | + /// |
| 184 | + /// * `data` - The hexadecimal GUID representation. |
| 185 | + /// |
| 186 | + /// # Returns |
| 187 | + /// |
| 188 | + /// An `Option<Guid>` containing the parsed GUID. |
| 189 | + #[must_use] |
| 190 | + pub fn parse_guid_from_hex(data: &str) -> Option<Guid> { |
| 191 | + let v: Vec<_> = Self::parse_bytes_from_hex(data).collect(); |
| 192 | + Some(Guid::from_bytes(v.try_into().ok()?)) |
| 193 | + } |
| 194 | +} |
| 195 | + |
| 196 | +impl FromStr for ConfigurationString { |
| 197 | + type Err = ParseError; |
| 198 | + |
| 199 | + fn from_str(bfr: &str) -> Result<Self, Self::Err> { |
| 200 | + let mut splitter = ConfigurationStringIter::new(bfr).peekable(); |
| 201 | + |
| 202 | + let guid = Self::try_parse_with(ParseError::ConfigHdr(ConfigHdrSection::Guid), || { |
| 203 | + let v = splitter.next()?; |
| 204 | + let v = (v.0 == "GUID").then_some(v.1).flatten()?; |
| 205 | + Self::parse_guid_from_hex(v) |
| 206 | + })?; |
| 207 | + let name = Self::try_parse_with(ParseError::ConfigHdr(ConfigHdrSection::Name), || { |
| 208 | + let v = splitter.next()?; |
| 209 | + let v = (v.0 == "NAME").then_some(v.1).flatten()?; |
| 210 | + Self::parse_string_from_hex(v) |
| 211 | + })?; |
| 212 | + let device_path = |
| 213 | + Self::try_parse_with(ParseError::ConfigHdr(ConfigHdrSection::Path), || { |
| 214 | + let v = splitter.next()?.1?; |
| 215 | + let v: Vec<_> = Self::parse_bytes_from_hex(v).collect(); |
| 216 | + let v = <&DevicePath>::try_from(v.as_slice()).ok()?; |
| 217 | + Some(v.to_boxed()) |
| 218 | + })?; |
| 219 | + |
| 220 | + let mut elements = Vec::new(); |
| 221 | + loop { |
| 222 | + let offset = match splitter.next() { |
| 223 | + Some(("OFFSET", Some(data))) => { |
| 224 | + Self::parse_number_from_hex(data).ok_or(ParseError::BlockName)? |
| 225 | + } |
| 226 | + None => break, |
| 227 | + _ => return Err(ParseError::BlockName), |
| 228 | + }; |
| 229 | + let width = match splitter.next() { |
| 230 | + Some(("WIDTH", Some(data))) => { |
| 231 | + Self::parse_number_from_hex(data).ok_or(ParseError::BlockName)? |
| 232 | + } |
| 233 | + _ => return Err(ParseError::BlockName), |
| 234 | + }; |
| 235 | + let value = match splitter.next() { |
| 236 | + Some(("VALUE", Some(data))) => Self::parse_bytes_from_hex(data).collect(), |
| 237 | + _ => return Err(ParseError::BlockConfig), |
| 238 | + }; |
| 239 | + |
| 240 | + while let Some(next) = splitter.peek() { |
| 241 | + if next.0 == "OFFSET" { |
| 242 | + break; |
| 243 | + } |
| 244 | + let _ = splitter.next(); // drop nvconfig entries for now |
| 245 | + } |
| 246 | + |
| 247 | + elements.push(ConfigurationStringElement { |
| 248 | + offset, |
| 249 | + width, |
| 250 | + value, |
| 251 | + }); |
| 252 | + } |
| 253 | + |
| 254 | + Ok(Self { |
| 255 | + guid, |
| 256 | + name, |
| 257 | + device_path, |
| 258 | + elements, |
| 259 | + }) |
| 260 | + } |
| 261 | +} |
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