syd 3.52.0

//
// Syd: rock-solid application kernel
// src/uts.rs: Interface to uname(2)
//
// Copyright (c) 2025, 2026 Ali Polatel <alip@chesswob.org>
//
// SPDX-License-Identifier: GPL-3.0

// SAFETY: This module has (almost) been liberated from unsafe code!
// UtsName::as_bytes() uses std::slice::from_raw_parts which is unsafe.
// Use deny rather than forbid so we can allow this case.
#![deny(unsafe_code)]

use std::fmt;

use serde::{ser::SerializeMap, Serialize, Serializer};

use crate::path::XPath;

// Length of the entries in `struct utsname' is 65.
pub(crate) const UTSNAME_LEN: usize = 65;

/// C-compatible layout of the `utsname` structure.
#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
#[repr(C)]
pub struct UtsName {
    // Name of the operating system implementation.
    pub(crate) sysname: [u8; UTSNAME_LEN],
    // Network name of this machine.
    pub(crate) nodename: [u8; UTSNAME_LEN],
    // Release level of the operating system.
    pub(crate) release: [u8; UTSNAME_LEN],
    // Version level of the operating system.
    pub(crate) version: [u8; UTSNAME_LEN],
    // Machine hardware platform.
    pub(crate) machine: [u8; UTSNAME_LEN],
    // NIS or YP domain name of this machine.
    pub(crate) domainname: [u8; UTSNAME_LEN],
}

impl Default for UtsName {
    fn default() -> Self {
        Self {
            sysname: [0u8; UTSNAME_LEN],
            nodename: [0u8; UTSNAME_LEN],
            release: [0u8; UTSNAME_LEN],
            version: [0u8; UTSNAME_LEN],
            machine: [0u8; UTSNAME_LEN],
            domainname: [0u8; UTSNAME_LEN],
        }
    }
}

impl UtsName {
    /// Return a byte-wise view of the UtsName structure.
    pub fn as_bytes(&self) -> &[u8] {
        // SAFETY: UtsName is repr(C) and contains only [u8; N] fields.
        #[expect(unsafe_code)]
        unsafe {
            std::slice::from_raw_parts(self as *const Self as *const u8, size_of::<Self>())
        }
    }

    /// Return name of the operating system implementation.
    pub fn sysname(&self) -> &XPath {
        XPath::from_bytes_until_nul(&self.sysname)
    }

    /// Return network name of this machine.
    pub fn nodename(&self) -> &XPath {
        XPath::from_bytes_until_nul(&self.nodename)
    }

    /// Return release level of the operating system.
    pub fn release(&self) -> &XPath {
        XPath::from_bytes_until_nul(&self.release)
    }

    /// Return version level of the operating system.
    pub fn version(&self) -> &XPath {
        XPath::from_bytes_until_nul(&self.version)
    }

    /// Return machine hardware platform.
    pub fn machine(&self) -> &XPath {
        XPath::from_bytes_until_nul(&self.machine)
    }

    /// Return NIS or YP domain name of this machine.
    pub fn domainname(&self) -> &XPath {
        XPath::from_bytes_until_nul(&self.domainname)
    }
}

impl fmt::Display for UtsName {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        writeln!(
            f,
            "{} version {} {}",
            self.sysname(),
            self.release(),
            self.version()
        )
    }
}

impl Serialize for UtsName {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        let mut map = serializer.serialize_map(Some(6))?;
        map.serialize_entry("sysname", self.sysname())?;
        map.serialize_entry("nodename", self.nodename())?;
        map.serialize_entry("release", self.release())?;
        map.serialize_entry("version", self.version())?;
        map.serialize_entry("machine", self.machine())?;
        map.serialize_entry("domainname", self.domainname())?;
        map.end()
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    fn make_field(s: &str) -> [u8; UTSNAME_LEN] {
        let mut buf = [0u8; UTSNAME_LEN];
        let bytes = s.as_bytes();
        buf[..bytes.len()].copy_from_slice(bytes);
        buf
    }

    fn make_utsname() -> UtsName {
        UtsName {
            sysname: make_field("Linux"),
            nodename: make_field("testhost"),
            release: make_field("6.1.0"),
            version: make_field("#1 SMP"),
            machine: make_field("x86_64"),
            domainname: make_field("localdomain"),
        }
    }

    #[test]
    fn test_utsname_1() {
        let uts = UtsName::default();
        assert!(uts.as_bytes().iter().all(|&b| b == 0));
    }

    #[test]
    fn test_utsname_2() {
        let uts = UtsName::default();
        assert_eq!(uts.as_bytes().len(), size_of::<UtsName>());
        assert_eq!(uts.as_bytes().len(), UTSNAME_LEN * 6);
    }

    #[test]
    fn test_utsname_3() {
        let uts = make_utsname();
        assert_eq!(uts.sysname().as_bytes(), b"Linux");
    }

    #[test]
    fn test_utsname_4() {
        let uts = make_utsname();
        assert_eq!(uts.nodename().as_bytes(), b"testhost");
    }

    #[test]
    fn test_utsname_5() {
        let uts = make_utsname();
        assert_eq!(uts.release().as_bytes(), b"6.1.0");
    }

    #[test]
    fn test_utsname_6() {
        let uts = make_utsname();
        assert_eq!(uts.version().as_bytes(), b"#1 SMP");
    }

    #[test]
    fn test_utsname_7() {
        let uts = make_utsname();
        assert_eq!(uts.machine().as_bytes(), b"x86_64");
    }

    #[test]
    fn test_utsname_8() {
        let uts = make_utsname();
        assert_eq!(uts.domainname().as_bytes(), b"localdomain");
    }

    #[test]
    fn test_utsname_9() {
        let uts = make_utsname();
        let display = format!("{uts}");
        assert!(display.contains("Linux"));
        assert!(display.contains("6.1.0"));
        assert!(display.contains("#1 SMP"));
    }

    #[test]
    fn test_utsname_10() {
        let uts = make_utsname();
        let json = serde_json::to_string(&uts).unwrap();
        assert!(json.contains("\"sysname\""));
        assert!(json.contains("\"nodename\""));
        assert!(json.contains("\"release\""));
        assert!(json.contains("\"version\""));
        assert!(json.contains("\"machine\""));
        assert!(json.contains("\"domainname\""));
        assert!(json.contains("Linux"));
        assert!(json.contains("testhost"));
    }

    #[test]
    fn test_utsname_11() {
        let uts = UtsName::default();
        assert!(uts.sysname().as_bytes().is_empty());
        assert!(uts.nodename().as_bytes().is_empty());
        assert!(uts.release().as_bytes().is_empty());
        assert!(uts.version().as_bytes().is_empty());
        assert!(uts.machine().as_bytes().is_empty());
        assert!(uts.domainname().as_bytes().is_empty());
    }

    #[test]
    fn test_utsname_12() {
        let uts = make_utsname();
        let uts2 = uts;
        assert_eq!(uts, uts2);
    }

    #[test]
    fn test_utsname_13() {
        let uts = make_utsname();
        let bytes = uts.as_bytes();
        assert_eq!(bytes[0], b'L');
        assert_eq!(bytes[1], b'i');
    }
}