/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this file,
 * You can obtain one at http://mozilla.org/MPL/2.0/. */

#[cfg(any(target_os = "linux", target_os = "android"))]
extern crate rust_minidump_writer_linux;

mod breakpad_crash_generator;
mod crash_generation;
mod ipc_server;
mod logging;
mod phc;
mod platform;

use crash_helper_common::{BreakpadData, BreakpadRawData, IPCConnector, IPCListener, Pid};
use std::{
    ffi::{c_char, CStr, OsString},
    fmt::Display,
};

use crash_generation::finalize_breakpad_minidump;
use ipc_server::{IPCServer, IPCServerState};

/// Runs the crash generator process logic, this includes the IPC used by
/// processes to signal that they crashed, the IPC used to retrieve crash
/// reports from the crash helper process and the logic used to generate the
/// actual minidumps. This function will return when the main process has
/// disconnected from the crash helper.
///
/// # Safety
///
/// `minidump_data`, `listener` and `pipe` must point to valid,
/// nul-terminated C strings. `breakpad_data` must be a valid file descriptor
/// (Linux) or point to a nul-terminated C string using either byte (macOS)
/// or wide characters (Windows).
#[cfg(not(target_os = "android"))]
#[no_mangle]
pub unsafe extern "C" fn crash_generator_logic_desktop(
    client_pid: Pid,
    client_handle: *const c_char,
    breakpad_data: BreakpadRawData,
    minidump_path: *const c_char,
    listener: *const c_char,
    pipe: *const c_char,
) -> i32 {
    // HACK: This constant is declared in the `mach2` crate but using a `c_uint`
    // type which makes it incompatible with the return value of
    // `bootstrap_look_up()` and thus prevents the `match` expression below from
    // compiling correctly. We re-declare it here as a `c_int` until upstream
    // issue #67 is fixed.
    #[cfg(any(target_os = "ios", target_os = "macos"))]
    const BOOTSTRAP_UNKNOWN_SERVICE: std::ffi::c_int = 1102;

    // SAFETY: We have not spawned any other threads at this point.
    unsafe {
        platform::daemonize();
    }

    logging::init();

    let client_handle = unsafe { CStr::from_ptr(client_handle) };
    let client_handle = unwrap_with_message(
        platform::get_client_handle(client_handle),
        "Could not deserialize the client process handle",
    );
    let breakpad_data = BreakpadData::new(breakpad_data);
    let minidump_path = unsafe { CStr::from_ptr(minidump_path) }
        .to_owned()
        .into_string()
        .unwrap();
    let minidump_path = OsString::from(minidump_path);
    let listener = unsafe { CStr::from_ptr(listener) };
    let listener = unwrap_with_message(
        IPCListener::deserialize(listener, client_pid),
        "Could not parse the crash generator's listener",
    );
    let pipe = unsafe { CStr::from_ptr(pipe) };
    let connector = IPCConnector::deserialize(pipe);
    let connector = match connector {
        // If the main process went down before we could deserialize the
        // connector then deserialization will fail, handle this case as an
        // expected error rather than a panic.
        #[cfg(any(target_os = "ios", target_os = "macos"))]
        Err(crash_helper_common::errors::IPCError::Deserialize(
            crash_helper_common::PlatformError::BootstrapLookUp(_rv @ BOOTSTRAP_UNKNOWN_SERVICE),
        )) => {
            log::error!("Could not reach out to the main process, shutting down");
            return -1;
        }
        Err(e) => {
            log::error!("Could not deserialize connector: {e:?}");
            return -1;
        }
        Ok(connector) => connector,
    };

    let ipc_server = IPCServer::new(
        client_pid,
        client_handle,
        listener,
        connector,
        breakpad_data,
        minidump_path,
    );

    match ipc_server {
        Ok(ipc_server) => main_loop(ipc_server),
        Err(e) => {
            log::error!("Could not create the IPC server (error: {e:?})");
            #[cfg(not(target_os = "android"))]
            panic!("Could not create the IPC server (error: {e:?})");
            #[allow(unreachable_code)]
            -1
        }
    }
}

/// Runs the crash generator process logic, this includes the IPC used by
/// processes to signal that they crashed, the IPC used to retrieve crash
/// reports from the crash helper process and the logic used to generate the
/// actual minidumps. The logic will run in a separate thread and this
/// function will return immediately after launching it.
///
/// # Safety
///
/// `minidump_data` must point to valid, nul-terminated C strings. `server_pipe`
/// must be a valid file descriptor and `breakpad_data` must also be a valid
/// file descriptor compatible with Breakpad's crash generation server.
#[cfg(target_os = "android")]
#[no_mangle]
pub unsafe extern "C" fn crash_generator_logic_android(
    pid: Pid,
    breakpad_data: BreakpadRawData,
    minidump_path: *const c_char,
    pipe: crash_helper_common::RawIPCConnector,
) {
    logging::init();

    let breakpad_data = BreakpadData::new(breakpad_data);
    let minidump_path = unsafe { CStr::from_ptr(minidump_path) }
        .to_owned()
        .into_string()
        .unwrap();
    let minidump_path = OsString::from(minidump_path);

    // On Android the main thread is used to respond to the intents so we
    // can't block it. Run the crash generation loop in a separate thread.
    let _ = std::thread::spawn(move || {
        let listener = IPCListener::new(0).unwrap();
        // SAFETY: The `pipe` file descriptor passed in from the caller is
        // guaranteed to be valid.
        let connector = unwrap_with_message(
            unsafe { IPCConnector::from_raw_connector(pipe) },
            "Could not use the pipe",
        );
        let ipc_server = unwrap_with_message(
            IPCServer::new(
                pid,
                /* client_handle */ None,
                listener,
                connector,
                breakpad_data,
                minidump_path,
            ),
            "Could not create the IPC server",
        );

        main_loop(ipc_server)
    });
}

fn main_loop(mut ipc_server: IPCServer) -> i32 {
    loop {
        match ipc_server.run() {
            Ok(_result @ IPCServerState::ClientDisconnected) => {
                return 0;
            }
            Err(error) => {
                log::error!("The crashhelper encountered an error, exiting (error: {error})");
                return -1;
            }
            _ => {} // Go on
        }
    }
}

fn unwrap_with_message<T, E: Display>(res: Result<T, E>, error_string: &str) -> T {
    match res {
        Ok(value) => value,
        Err(error) => {
            log::error!("{error_string} (error: {error})");
            panic!("{} (error: {})", error_string, error);
        }
    }
}
