// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License..

use sgx_build_helper as build_helper;
use self::build_helper::native_lib_boilerplate;
use std::env;
use std::fs::File;

fn main() {
    let target = env::var("TARGET").expect("TARGET was not set");
    let _ = build_libbacktrace(&target);
}

fn build_libbacktrace(_target: &str) -> Result<(), ()> {
    let sdk_dir = env::var("SGX_SDK")
                    .unwrap_or_else(|_| "/opt/intel/sgxsdk".to_string());
    let sdk_include = format!("{}/{}", sdk_dir, "include");

    let native = native_lib_boilerplate(
                    "sgx_backtrace_sys/libbacktrace",
                    "libbacktrace",
                    "backtrace",
                    "",
                    &vec![])?;

    let mut build = cc::Build::new();
    build
        .opt_level(2)
        .flag("-fstack-protector")
        .flag("-ffreestanding")
        .flag("-fpie")
        .flag("-fno-strict-overflow")
        .flag("-fno-delete-null-pointer-checks")
        .flag("-fvisibility=hidden")
        .include("./libbacktrace")
        .include(&native.out_dir)
        .include(&sdk_include)
        .out_dir(&native.out_dir)
        .warnings(false)
        .file("./libbacktrace/mmap.c")
        .file("./libbacktrace/mmapio.c")
        .file("./libbacktrace/backtrace.c")
        .file("./libbacktrace/dwarf.c")
        .file("./libbacktrace/fileline.c")
        .file("./libbacktrace/posix.c")
        .file("./libbacktrace/sort.c")
        .file("./libbacktrace/state.c");

    let mitigation_cflags1 = "-mindirect-branch-register";
    let mitigation_cflags2 = "-mfunction-return=thunk-extern";
    let mitigation_asflags = "-fno-plt";
    let mitigation_loadflags1 = "-Wa,-mlfence-after-load=yes";
    let mitigation_loadflags2 = "-Wa,-mlfence-before-ret=not";
    let mitigation_cfflags1 = "-Wa,-mlfence-before-indirect-branch=register";
    let mitigation_cfflags2 = "-Wa,-mlfence-before-ret=not";
    let mitigation = env::var("MITIGATION_CVE_2020_0551").unwrap_or_default();
    match mitigation.as_ref() {
        "LOAD" => {
            build
                .flag(mitigation_cflags1)
                .flag(mitigation_cflags2)
                .flag(mitigation_asflags)
                .flag(mitigation_loadflags1)
                .flag(mitigation_loadflags2);
        },
        "CF" => {
            build
                .flag(mitigation_cflags1)
                .flag(mitigation_cflags2)
                .flag(mitigation_asflags)
                .flag(mitigation_cfflags1)
                .flag(mitigation_cfflags2);
        },
        _  => {},
    }

    let any_debug = env::var("RUSTC_DEBUGINFO").unwrap_or_default() == "true" ||
        env::var("RUSTC_DEBUGINFO_LINES").unwrap_or_default() == "true";
    build.debug(any_debug);

    build.file("./libbacktrace/elf.c");

    let pointer_width = env::var("CARGO_CFG_TARGET_POINTER_WIDTH").unwrap();
    if pointer_width == "64" {
        build.define("BACKTRACE_ELF_SIZE", "64");
    } else {
        build.define("BACKTRACE_ELF_SIZE", "32");
    }

    File::create(native.out_dir.join("backtrace-supported.h")).unwrap();
    build.define("BACKTRACE_SUPPORTED", "1");
    build.define("BACKTRACE_USES_MALLOC", "0");
    build.define("BACKTRACE_SUPPORTS_THREADS", "0");
    build.define("BACKTRACE_SUPPORTS_DATA", "0");

    File::create(native.out_dir.join("config.h")).unwrap();
    build.define("HAVE_DL_ITERATE_PHDR", "1");
    build.define("_GNU_SOURCE", "1");
    build.define("_LARGE_FILES", "1");

    build.compile("backtrace");
    Ok(())
}