//! Two-volume mount traversal constrained by a process root.

use super::*;
use os_vfs_paths::{Error as PathError, Mount, MountNamespace, PathState};

pub fn run(allocator: &mut memory::FrameAllocator) -> Result<(), &'static str> {
    let frames_before = allocator.remaining_pages();
    let resolver = PathState::new();
    let root = resolver.resolve(b"/sandbox").map_err(|_| "k1550-root")?;
    let first = Mount::new(resolver.resolve(b"/sandbox/veri")
        .map_err(|_| "k1550-first-path")?, 1)
        .map_err(|_| "k1550-first-mount")?;
    let second = Mount::new(resolver.resolve(b"/sandbox/ara")
        .map_err(|_| "k1550-second-path")?, 2)
        .map_err(|_| "k1550-second-mount")?;
    let mut namespace = MountNamespace::new(root, first, second)
        .map_err(|_| "k1550-namespace")?;
    {
        let route = namespace.chdir(b"/veri/alt")
            .map_err(|_| "k1550-first-route")?;
        if route.volume != 1 || route.relative_depth != 1
            || route.path.component(2) != Some("alt") {
            return Err("k1550-first-result");
        }
    }
    {
        let route = namespace.chdir(b"../../ara/alt")
            .map_err(|_| "k1550-cross-route")?;
        if route.volume != 2 || route.relative_depth != 1
            || route.path.component(1) != Some("ara")
            || namespace.generation != 2 {
            return Err("k1550-cross-result");
        }
    }
    let cwd = namespace.cwd;
    if namespace.chdir(b"../../../gizli") != Err(PathError::AboveRoot)
        || namespace.cwd != cwd || namespace.generation != 2 {
        return Err("k1550-root-escape");
    }
    if namespace.chdir(b"/bilinmeyen") != Err(PathError::NoMount)
        || namespace.cwd != cwd || namespace.generation != 2
        || allocator.remaining_pages() != frames_before {
        return Err("k1550-unmounted-route");
    }
    write_line("TURKOS/OS/K1550-MOUNT: FIRST=1 SECOND=2 CROSS=VALID ROOT-ESCAPE=REJECTED CWD=UNCHANGED FRAMES=UNCHANGED");
    Ok(())
}