armybox 0.3.0

A memory-safe #[no_std] BusyBox/Toybox clone in Rust - 299 Unix utilities in ~500KB
Documentation 
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//! fgconsole - print the number of the active VT
//!
//! Print the number of the currently active virtual terminal.

use crate::io;

/// fgconsole - print the number of the active VT
///
/// # Synopsis
/// ```text
/// fgconsole
/// ```
///
/// # Description
/// Print the number of the currently active virtual terminal.
///
/// # Exit Status
/// - 0: Success
/// - 1: Error
pub fn fgconsole(_argc: i32, _argv: *const *const u8) -> i32 {
    // Try to get current VT from /sys/class/tty/tty0/active
    let fd = io::open(b"/sys/class/tty/tty0/active", libc::O_RDONLY, 0);
    if fd >= 0 {
        let mut buf = [0u8; 32];
        let n = io::read(fd, &mut buf);
        io::close(fd);

        if n > 0 {
            // Parse "ttyN" to get N
            let content = &buf[..n as usize];
            if content.starts_with(b"tty") {
                let num_start = 3;
                let num_end = content.iter().position(|&c| c == b'\n' || c == 0).unwrap_or(n as usize);
                if num_end > num_start {
                    io::write_all(1, &content[num_start..num_end]);
                    io::write_str(1, b"\n");
                    return 0;
                }
            }
        }
    }

    // Fallback - assume VT 1
    io::write_str(1, b"1\n");
    0
}

#[cfg(test)]
mod tests {
    extern crate std;
    use std::process::Command;
    use std::path::PathBuf;

    fn get_armybox_path() -> PathBuf {
        if let Ok(path) = std::env::var("ARMYBOX_PATH") {
            return PathBuf::from(path);
        }
        let manifest_dir = std::env::var("CARGO_MANIFEST_DIR")
            .map(PathBuf::from)
            .unwrap_or_else(|_| std::env::current_dir().unwrap());
        let release = manifest_dir.join("target/release/armybox");
        if release.exists() { return release; }
        manifest_dir.join("target/debug/armybox")
    }

    #[test]
    fn test_fgconsole_runs() {
        let armybox = get_armybox_path();
        if !armybox.exists() { return; }

        let output = Command::new(&armybox)
            .args(["fgconsole"])
            .output()
            .unwrap();

        assert_eq!(output.status.code(), Some(0));
        // Should output a number
        let stdout = std::string::String::from_utf8_lossy(&output.stdout);
        assert!(!stdout.is_empty());
    }
}