// Copyright 2021, The Android Open Source Project
//
// Licensed 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.

//! Payload disk image

use android_system_virtualizationservice::aidl::android::system::virtualizationservice::{
    DiskImage::DiskImage,
    Partition::Partition,
    VirtualMachineAppConfig::DebugLevel::DebugLevel,
    VirtualMachineAppConfig::{Payload::Payload, VirtualMachineAppConfig},
    VirtualMachineRawConfig::VirtualMachineRawConfig,
};
use anyhow::{anyhow, bail, Context, Result};
use binder::{wait_for_interface, ParcelFileDescriptor};
use log::{info, warn};
use microdroid_metadata::{ApexPayload, ApkPayload, Metadata, PayloadConfig, PayloadMetadata};
use microdroid_payload_config::{ApexConfig, VmPayloadConfig};
use once_cell::sync::OnceCell;
use packagemanager_aidl::aidl::android::content::pm::IPackageManagerNative::IPackageManagerNative;
use regex::Regex;
use serde::Deserialize;
use serde_xml_rs::from_reader;
use std::collections::HashSet;
use std::fs::{metadata, File, OpenOptions};
use std::path::{Path, PathBuf};
use std::process::Command;
use std::time::SystemTime;
use vmconfig::open_parcel_file;

/// The list of APEXes which microdroid requires.
// TODO(b/192200378) move this to microdroid.json?
const MICRODROID_REQUIRED_APEXES: [&str; 1] = ["com.android.os.statsd"];
const MICRODROID_REQUIRED_APEXES_DEBUG: [&str; 1] = ["com.android.adbd"];

const APEX_INFO_LIST_PATH: &str = "/apex/apex-info-list.xml";

const PACKAGE_MANAGER_NATIVE_SERVICE: &str = "package_native";

/// Represents the list of APEXes
#[derive(Clone, Debug, Deserialize)]
struct ApexInfoList {
    #[serde(rename = "apex-info")]
    list: Vec<ApexInfo>,
}

#[derive(Clone, Debug, Default, Deserialize, Eq, PartialEq)]
struct ApexInfo {
    #[serde(rename = "moduleName")]
    name: String,
    #[serde(rename = "modulePath")]
    path: PathBuf,

    #[serde(default)]
    has_classpath_jar: bool,

    // The field claims to be milliseconds but is actually seconds.
    #[serde(rename = "lastUpdateMillis")]
    last_update_seconds: u64,

    #[serde(rename = "isFactory")]
    is_factory: bool,

    #[serde(rename = "isActive")]
    is_active: bool,

    #[serde(rename = "provideSharedApexLibs")]
    provide_shared_apex_libs: bool,
}

impl ApexInfoList {
    /// Loads ApexInfoList
    fn load() -> Result<&'static ApexInfoList> {
        static INSTANCE: OnceCell<ApexInfoList> = OnceCell::new();
        INSTANCE.get_or_try_init(|| {
            let apex_info_list = File::open(APEX_INFO_LIST_PATH)
                .context(format!("Failed to open {}", APEX_INFO_LIST_PATH))?;
            let mut apex_info_list: ApexInfoList = from_reader(apex_info_list)
                .context(format!("Failed to parse {}", APEX_INFO_LIST_PATH))?;

            // For active APEXes, we run derive_classpath and parse its output to see if it
            // contributes to the classpath(s). (This allows us to handle any new classpath env
            // vars seamlessly.)
            let classpath_vars = run_derive_classpath()?;
            let classpath_apexes = find_apex_names_in_classpath(&classpath_vars)?;

            for apex_info in apex_info_list.list.iter_mut() {
                apex_info.has_classpath_jar = classpath_apexes.contains(&apex_info.name);
            }

            Ok(apex_info_list)
        })
    }
}

impl ApexInfo {
    fn matches(&self, apex_config: &ApexConfig) -> bool {
        // Match with pseudo name "{CLASSPATH}" which represents APEXes contributing
        // to any derive_classpath environment variable
        if apex_config.name == "{CLASSPATH}" && self.has_classpath_jar {
            return true;
        }
        if apex_config.name == self.name {
            return true;
        }
        false
    }
}

struct PackageManager {
    apex_info_list: &'static ApexInfoList,
}

impl PackageManager {
    fn new() -> Result<Self> {
        let apex_info_list = ApexInfoList::load()?;
        Ok(Self { apex_info_list })
    }

    fn get_apex_list(&self, prefer_staged: bool) -> Result<ApexInfoList> {
        // get the list of active apexes
        let mut list = self.apex_info_list.clone();
        // When prefer_staged, we override ApexInfo by consulting "package_native"
        if prefer_staged {
            let pm =
                wait_for_interface::<dyn IPackageManagerNative>(PACKAGE_MANAGER_NATIVE_SERVICE)
                    .context("Failed to get service when prefer_staged is set.")?;
            let staged =
                pm.getStagedApexModuleNames().context("getStagedApexModuleNames failed")?;
            for apex_info in list.list.iter_mut() {
                if staged.contains(&apex_info.name) {
                    if let Some(staged_apex_info) =
                        pm.getStagedApexInfo(&apex_info.name).context("getStagedApexInfo failed")?
                    {
                        apex_info.path = PathBuf::from(staged_apex_info.diskImagePath);
                        apex_info.has_classpath_jar = staged_apex_info.hasClassPathJars;
                        let metadata = metadata(&apex_info.path)?;
                        apex_info.last_update_seconds =
                            metadata.modified()?.duration_since(SystemTime::UNIX_EPOCH)?.as_secs();
                        // by definition, staged apex can't be a factory apex.
                        apex_info.is_factory = false;
                    }
                }
            }
        }
        Ok(list)
    }
}

fn make_metadata_file(
    app_config: &VirtualMachineAppConfig,
    apex_infos: &[&ApexInfo],
    temporary_directory: &Path,
) -> Result<ParcelFileDescriptor> {
    let payload_metadata = match &app_config.payload {
        Payload::PayloadConfig(payload_config) => PayloadMetadata::config(PayloadConfig {
            payload_binary_path: payload_config.payloadPath.clone(),
            args: payload_config.args.clone().into(),
            ..Default::default()
        }),
        Payload::ConfigPath(config_path) => {
            PayloadMetadata::config_path(format!("/mnt/apk/{}", config_path))
        }
    };

    let metadata = Metadata {
        version: 1,
        apexes: apex_infos
            .iter()
            .enumerate()
            .map(|(i, apex_info)| {
                Ok(ApexPayload {
                    name: apex_info.name.clone(),
                    partition_name: format!("microdroid-apex-{}", i),
                    last_update_seconds: apex_info.last_update_seconds,
                    is_factory: apex_info.is_factory,
                    ..Default::default()
                })
            })
            .collect::<Result<_>>()?,
        apk: Some(ApkPayload {
            name: "apk".to_owned(),
            payload_partition_name: "microdroid-apk".to_owned(),
            idsig_partition_name: "microdroid-apk-idsig".to_owned(),
            ..Default::default()
        })
        .into(),
        payload: Some(payload_metadata),
        ..Default::default()
    };

    // Write metadata to file.
    let metadata_path = temporary_directory.join("metadata");
    let mut metadata_file = OpenOptions::new()
        .create_new(true)
        .read(true)
        .write(true)
        .open(&metadata_path)
        .with_context(|| format!("Failed to open metadata file {:?}", metadata_path))?;
    microdroid_metadata::write_metadata(&metadata, &mut metadata_file)?;

    // Re-open the metadata file as read-only.
    open_parcel_file(&metadata_path, false)
}

/// Creates a DiskImage with partitions:
///   payload-metadata: metadata
///   microdroid-apex-0: apex 0
///   microdroid-apex-1: apex 1
///   ..
///   microdroid-apk: apk
///   microdroid-apk-idsig: idsig
///   extra-apk-0:   additional apk 0
///   extra-idsig-0: additional idsig 0
///   extra-apk-1:   additional apk 1
///   extra-idsig-1: additional idsig 1
///   ..
fn make_payload_disk(
    app_config: &VirtualMachineAppConfig,
    apk_file: File,
    idsig_file: File,
    vm_payload_config: &VmPayloadConfig,
    temporary_directory: &Path,
) -> Result<DiskImage> {
    if vm_payload_config.extra_apks.len() != app_config.extraIdsigs.len() {
        bail!(
            "payload config has {} apks, but app config has {} idsigs",
            vm_payload_config.extra_apks.len(),
            app_config.extraIdsigs.len()
        );
    }

    let pm = PackageManager::new()?;
    let apex_list = pm.get_apex_list(vm_payload_config.prefer_staged)?;

    // collect APEXes from config
    let apex_infos =
        collect_apex_infos(&apex_list, &vm_payload_config.apexes, app_config.debugLevel);
    info!("Microdroid payload APEXes: {:?}", apex_infos.iter().map(|ai| &ai.name));

    let metadata_file = make_metadata_file(app_config, &apex_infos, temporary_directory)?;
    // put metadata at the first partition
    let mut partitions = vec![Partition {
        label: "payload-metadata".to_owned(),
        image: Some(metadata_file),
        writable: false,
    }];

    for (i, apex_info) in apex_infos.iter().enumerate() {
        let apex_file = open_parcel_file(&apex_info.path, false)?;
        partitions.push(Partition {
            label: format!("microdroid-apex-{}", i),
            image: Some(apex_file),
            writable: false,
        });
    }
    partitions.push(Partition {
        label: "microdroid-apk".to_owned(),
        image: Some(ParcelFileDescriptor::new(apk_file)),
        writable: false,
    });
    partitions.push(Partition {
        label: "microdroid-apk-idsig".to_owned(),
        image: Some(ParcelFileDescriptor::new(idsig_file)),
        writable: false,
    });

    // we've already checked that extra_apks and extraIdsigs are in the same size.
    let extra_apks = &vm_payload_config.extra_apks;
    let extra_idsigs = &app_config.extraIdsigs;
    for (i, (extra_apk, extra_idsig)) in extra_apks.iter().zip(extra_idsigs.iter()).enumerate() {
        partitions.push(Partition {
            label: format!("extra-apk-{}", i),
            image: Some(ParcelFileDescriptor::new(
                File::open(PathBuf::from(&extra_apk.path)).with_context(|| {
                    format!("Failed to open the extra apk #{} {}", i, extra_apk.path)
                })?,
            )),
            writable: false,
        });

        partitions.push(Partition {
            label: format!("extra-idsig-{}", i),
            image: Some(ParcelFileDescriptor::new(
                extra_idsig
                    .as_ref()
                    .try_clone()
                    .with_context(|| format!("Failed to clone the extra idsig #{}", i))?,
            )),
            writable: false,
        });
    }

    Ok(DiskImage { image: None, partitions, writable: false })
}

fn run_derive_classpath() -> Result<String> {
    let result = Command::new("/apex/com.android.sdkext/bin/derive_classpath")
        .arg("/proc/self/fd/1")
        .output()
        .context("Failed to run derive_classpath")?;

    if !result.status.success() {
        bail!("derive_classpath returned {}", result.status);
    }

    String::from_utf8(result.stdout).context("Converting derive_classpath output")
}

fn find_apex_names_in_classpath(classpath_vars: &str) -> Result<HashSet<String>> {
    // Each line should be in the format "export <var name> <paths>", where <paths> is a
    // colon-separated list of paths to JARs. We don't care about the var names, and we're only
    // interested in paths that look like "/apex/<apex name>/<anything>" so we know which APEXes
    // contribute to at least one var.
    let mut apexes = HashSet::new();

    let pattern = Regex::new(r"^export [^ ]+ ([^ ]+)$").context("Failed to construct Regex")?;
    for line in classpath_vars.lines() {
        if let Some(captures) = pattern.captures(line) {
            if let Some(paths) = captures.get(1) {
                apexes.extend(paths.as_str().split(':').filter_map(|path| {
                    let path = path.strip_prefix("/apex/")?;
                    Some(path[..path.find('/')?].to_owned())
                }));
                continue;
            }
        }
        warn!("Malformed line from derive_classpath: {}", line);
    }

    Ok(apexes)
}

// Collect ApexInfos from VM config
fn collect_apex_infos<'a>(
    apex_list: &'a ApexInfoList,
    apex_configs: &[ApexConfig],
    debug_level: DebugLevel,
) -> Vec<&'a ApexInfo> {
    let mut additional_apexes: Vec<&str> = MICRODROID_REQUIRED_APEXES.to_vec();
    if debug_level != DebugLevel::NONE {
        additional_apexes.extend(MICRODROID_REQUIRED_APEXES_DEBUG.to_vec());
    }

    apex_list
        .list
        .iter()
        .filter(|ai| {
            apex_configs.iter().any(|cfg| ai.matches(cfg) && ai.is_active)
                || additional_apexes.iter().any(|name| name == &ai.name && ai.is_active)
                || ai.provide_shared_apex_libs
        })
        .collect()
}

pub fn add_microdroid_images(
    config: &VirtualMachineAppConfig,
    temporary_directory: &Path,
    apk_file: File,
    idsig_file: File,
    instance_file: File,
    vm_payload_config: &VmPayloadConfig,
    vm_config: &mut VirtualMachineRawConfig,
) -> Result<()> {
    let debug_suffix = match config.debugLevel {
        DebugLevel::NONE => "normal",
        DebugLevel::APP_ONLY => "app_debuggable",
        DebugLevel::FULL => "full_debuggable",
        _ => return Err(anyhow!("unsupported debug level: {:?}", config.debugLevel)),
    };
    let initrd = format!("/apex/com.android.virt/etc/microdroid_initrd_{}.img", debug_suffix);
    vm_config.initrd = Some(open_parcel_file(Path::new(&initrd), false)?);

    let instance_img = Partition {
        label: "vm-instance".to_owned(),
        image: Some(ParcelFileDescriptor::new(instance_file)),
        writable: true,
    };
    vm_config.disks.push(DiskImage { image: None, partitions: vec![instance_img], writable: true });
    vm_config.disks.push(make_payload_disk(
        config,
        apk_file,
        idsig_file,
        vm_payload_config,
        temporary_directory,
    )?);

    Ok(())
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_find_apex_names_in_classpath() {
        let vars = r#"
export FOO /apex/unterminated
export BAR /apex/valid.apex/something
wrong
export EMPTY
export OTHER /foo/bar:/baz:/apex/second.valid.apex/:gibberish:"#;
        let expected = vec!["valid.apex", "second.valid.apex"];
        let expected: HashSet<_> = expected.into_iter().map(ToString::to_string).collect();

        assert_eq!(find_apex_names_in_classpath(vars).unwrap(), expected);
    }

    #[test]
    fn test_collect_apexes() {
        let apex_info_list = ApexInfoList {
            list: vec![
                ApexInfo {
                    // 0
                    name: "com.android.adbd".to_string(),
                    path: PathBuf::from("adbd"),
                    has_classpath_jar: false,
                    last_update_seconds: 12345678,
                    is_factory: true,
                    is_active: true,
                    ..Default::default()
                },
                ApexInfo {
                    // 1
                    name: "com.android.os.statsd".to_string(),
                    path: PathBuf::from("statsd"),
                    has_classpath_jar: false,
                    last_update_seconds: 12345678,
                    is_factory: true,
                    is_active: false,
                    ..Default::default()
                },
                ApexInfo {
                    // 2
                    name: "com.android.os.statsd".to_string(),
                    path: PathBuf::from("statsd/updated"),
                    has_classpath_jar: false,
                    last_update_seconds: 12345678 + 1,
                    is_factory: false,
                    is_active: true,
                    ..Default::default()
                },
                ApexInfo {
                    // 3
                    name: "no_classpath".to_string(),
                    path: PathBuf::from("no_classpath"),
                    has_classpath_jar: false,
                    last_update_seconds: 12345678,
                    is_factory: true,
                    is_active: true,
                    ..Default::default()
                },
                ApexInfo {
                    // 4
                    name: "has_classpath".to_string(),
                    path: PathBuf::from("has_classpath"),
                    has_classpath_jar: true,
                    last_update_seconds: 87654321,
                    is_factory: true,
                    is_active: false,
                    ..Default::default()
                },
                ApexInfo {
                    // 5
                    name: "has_classpath".to_string(),
                    path: PathBuf::from("has_classpath/updated"),
                    has_classpath_jar: true,
                    last_update_seconds: 87654321 + 1,
                    is_factory: false,
                    is_active: true,
                    ..Default::default()
                },
                ApexInfo {
                    // 6
                    name: "apex-foo".to_string(),
                    path: PathBuf::from("apex-foo"),
                    has_classpath_jar: false,
                    last_update_seconds: 87654321,
                    is_factory: true,
                    is_active: false,
                    ..Default::default()
                },
                ApexInfo {
                    // 7
                    name: "apex-foo".to_string(),
                    path: PathBuf::from("apex-foo/updated"),
                    has_classpath_jar: false,
                    last_update_seconds: 87654321 + 1,
                    is_factory: false,
                    is_active: true,
                    ..Default::default()
                },
                ApexInfo {
                    // 8
                    name: "sharedlibs".to_string(),
                    path: PathBuf::from("apex-foo"),
                    last_update_seconds: 87654321,
                    is_factory: true,
                    provide_shared_apex_libs: true,
                    ..Default::default()
                },
                ApexInfo {
                    // 9
                    name: "sharedlibs".to_string(),
                    path: PathBuf::from("apex-foo/updated"),
                    last_update_seconds: 87654321 + 1,
                    is_active: true,
                    provide_shared_apex_libs: true,
                    ..Default::default()
                },
            ],
        };
        let apex_configs = vec![
            ApexConfig { name: "apex-foo".to_string() },
            ApexConfig { name: "{CLASSPATH}".to_string() },
        ];
        assert_eq!(
            collect_apex_infos(&apex_info_list, &apex_configs, DebugLevel::FULL),
            vec![
                // Pass active/required APEXes
                &apex_info_list.list[0],
                &apex_info_list.list[2],
                // Pass active APEXes specified in the config
                &apex_info_list.list[5],
                &apex_info_list.list[7],
                // Pass both preinstalled(inactive) and updated(active) for "sharedlibs" APEXes
                &apex_info_list.list[8],
                &apex_info_list.list[9],
            ]
        );
    }
}