//! Stage 21: boot contract v2. scripts/qemu.sh gives this test kernel one
//! more disk, target/rootfs-gpt.img (build.rs): a GPT disk with an ext2
//! partition of type "Linux root (x86-64)" and an exFAT "Microsoft basic
//! data" partition. Its /sbin/init, /bin/init and /bin/sh are all
//! user/inittest.c, which exits 7 (from /etc/init-status) when every check
//! passes as /sbin/init, 21 as /bin/init and 22 as /bin/sh.
//!
//! (The other half, "no root partition = the old layout", is checked by
//! tests/fat.rs and by scripts/run-headless.sh; main.rs's use of all this,
//! with QEMU's exit code, by scripts/boot-v2-check.sh.)
#![no_std]
#![no_main]
#![feature(custom_test_frameworks)]
#![test_runner(rustbelt::test_runner)]
#![reexport_test_harness_main = "test_main"]

extern crate alloc;

use alloc::string::String;
use alloc::vec::Vec;
use bootloader::{BootInfo, entry_point};
use core::panic::PanicInfo;
use rustbelt::boot;
use rustbelt::errno::Errno;
use rustbelt::fs::{self, InodeKind};
use rustbelt::process::{self, ExitStatus};
use rustbelt::{memory, thread};

entry_point!(main);

fn main(boot_info: &'static BootInfo) -> ! {
    rustbelt::init();
    rustbelt::init_memory(boot_info);
    rustbelt::init_smp();
    fs::init();
    rustbelt::init_storage();
    rustbelt::timer::start(); // (its kernel stack isn't a leak)
    test_main();
    rustbelt::hlt_loop();
}

fn mount_type(path: &str) -> Option<&'static str> {
    fs::mounts().into_iter().find(|(p, _)| p == path).map(|(_, t)| t)
}

/// The first process this kernel starts: /sbin/init as pid 1. inittest
/// checks pid 1, argv, PATH, the mounts, /mnt/share and msync itself, and
/// exits 7 only if all of that held.
#[test_case]
fn init_runs_as_pid_1_and_its_status_comes_back() {
    let mut log = Vec::new();
    let before = memory::frames_in_use();
    let (path, status) = boot::run_init(false, &mut log).expect("no init started");
    assert_eq!(path, "/sbin/init");
    assert_eq!(status, ExitStatus::Exited(7), "inittest's checks failed (see its [inittest] lines)");
    assert!(log.is_empty(), "{:?}", log);
    // What init wrote to the share is really there.
    assert_eq!(fs::read_all("/mnt/share/from-init.txt").unwrap(), b"written by init\n");
    thread::sleep_ticks(3);
    assert_eq!(process::count(), 0);
    assert_eq!(memory::frames_in_use(), before, "running init leaked frames");
}

#[test_case]
fn the_root_partition_is_slash_and_the_rest_is_as_before() {
    assert!(boot::v2());
    assert_eq!(mount_type("/"), Some("ext2"));
    assert!(fs::read_all("/etc/rootfs-v2").unwrap().starts_with(b"This is the ext2 root"));
    // The kernel's own mounts are still there...
    assert_eq!(mount_type("/tmp"), Some("ramfs"));
    assert!(mount_type("/dev").is_some() && mount_type("/proc").is_some());
    // ...the FAT32 data disk is still /mnt/disk0 (B:), and the other disks
    // keep their numbers: the root and the share don't take one.
    assert_eq!(mount_type("/mnt/disk0"), Some("fat32"));
    assert_eq!(mount_type("/mnt/disk1"), Some("ext2"));
    assert_eq!(mount_type("/mnt/disk2"), Some("exfat"));
    assert!(mount_type("/mnt/disk9").is_some());
    assert!(mount_type("/mnt/disk10").is_none());
    assert!(fs::lookup("/mnt/disk0/bin").is_ok());
    // The exFAT partition is the share, mounted read-write.
    assert_eq!(mount_type("/mnt/share"), Some("exfat"));
    assert_eq!(fs::read_all("/mnt/share/hello.txt").unwrap(), b"Hello from the exFAT share!\n");
    let f = fs::create("/mnt/share/kernel.txt", InodeKind::File).unwrap();
    f.write_at(0, b"rw").unwrap();
    assert_eq!(fs::read_all("/mnt/share/kernel.txt").unwrap(), b"rw");
    fs::remove("/mnt/share/kernel.txt", false).unwrap();
}

#[test_case]
fn init_gets_the_documented_argv_and_env() {
    let s = |v: &[&str]| v.iter().map(|x| String::from(*x)).collect::<Vec<_>>();
    let a = boot::init_args("/sbin/init", false);
    assert_eq!(a.args, s(&["init"]));
    assert_eq!(a.env, s(&["PATH=/sbin:/bin:/usr/bin:/mnt/disk0/bin", "HOME=/", "TERM=linux"]));
    let a = boot::init_args("/bin/init", true);
    assert_eq!(a.args, s(&["init", "selftest"]));
    assert!(a.env.iter().any(|e| e == "RUSTBELT_HEADLESS=1"));
    let a = boot::init_args("/bin/sh", true);
    assert_eq!(a.args, s(&["sh", "/scripts/selftest.sh"]));
}

/// Take away /sbin/init, then /bin/init, then /bin/sh (the disk is
/// snapshot=on, so the file stays): the next one in line starts each time.
#[test_case]
fn the_fallback_chain() {
    let mut log = Vec::new();
    fs::remove("/sbin/init", false).unwrap();
    assert_eq!(boot::run_init(false, &mut log), Ok(("/bin/init", ExitStatus::Exited(21))));
    fs::remove("/bin/init", false).unwrap();
    assert_eq!(boot::run_init(false, &mut log), Ok(("/bin/sh", ExitStatus::Exited(22))));
    fs::remove("/bin/sh", false).unwrap();
    assert_eq!(boot::run_init(false, &mut log), Err(Errno::ENOENT));
    // Something that isn't a program is skipped (and logged), like Linux.
    fs::create("/sbin/init", InodeKind::File).unwrap().write_at(0, b"not an ELF file").unwrap();
    assert_eq!(boot::run_init(false, &mut log), Err(Errno::ENOENT));
    assert_eq!(log.len(), 1, "{:?}", log);
    assert!(log[0].starts_with("/sbin/init: can't start it"), "{:?}", log);
}

/// pid 1's status -> the value for isa-debug-exit (QEMU exits with
/// 2 * value + 1): exit(n) -> 33 + 2n.
#[test_case]
fn exit_status_to_qemu() {
    assert_eq!(boot::qemu_exit_value(ExitStatus::Exited(0)), 0x10); // 33, as before
    assert_eq!(boot::qemu_exit_value(ExitStatus::Exited(1)), 0x11); // 35, as before
    assert_eq!(boot::qemu_exit_value(ExitStatus::Exited(7)), 0x17); // 47
    assert_eq!(boot::qemu_exit_value(ExitStatus::Exited(111)), 0x7f); // 255
    assert_eq!(boot::qemu_exit_value(ExitStatus::Exited(112)), 0x11);
    assert_eq!(boot::qemu_exit_value(ExitStatus::Killed(9, "SIGKILL")), 0x11);
}

#[panic_handler]
fn panic(info: &PanicInfo) -> ! {
    rustbelt::test_panic_handler(info)
}