// Copyright (C) 2023 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.

#include <liburing.h>
#include <sys/resource.h>
#include <sys/utsname.h>
#include <unistd.h>

#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/properties.h>
#include <com_android_libsnapshot.h>
#include <libdm/dm.h>
#include <processgroup/processgroup.h>

#include <private/android_filesystem_config.h>

#include "utility.h"

namespace android {
namespace snapshot {

using android::base::unique_fd;
using android::dm::DeviceMapper;

bool SetThreadPriority([[maybe_unused]] int priority) {
#ifdef __ANDROID__
    return setpriority(PRIO_PROCESS, gettid(), priority) != -1;
#else
    return true;
#endif
}

bool SetProfiles([[maybe_unused]] std::initializer_list<std::string_view> profiles) {
#ifdef __ANDROID__
    if (setgid(AID_SYSTEM)) {
        return false;
    }
    return SetTaskProfiles(gettid(), profiles);
#else
    return true;
#endif
}

bool KernelSupportsIoUring() {
    struct utsname uts{};
    unsigned int major, minor;

    uname(&uts);
    if (sscanf(uts.release, "%u.%u", &major, &minor) != 2) {
        return false;
    }

    return major > 5 || (major == 5 && minor >= 6);
}

bool KernelSupportsDeferTask() {
    struct utsname uts{};
    unsigned int major, minor;

    uname(&uts);
    if (sscanf(uts.release, "%u.%u", &major, &minor) != 2) {
        return false;
    }

    // See InitializeUringForMerge() - Flags passed for ring initialization
    // requires kernel version 6.1+
    return major > 6 || (major == 6 && minor >= 1);
}

bool KernelSupportsCompressedSnapshots() {
    auto& dm = DeviceMapper::Instance();
    return dm.GetTargetByName("user", nullptr);
}

bool CanUseUserspaceSnapshots() {
    if (!KernelSupportsCompressedSnapshots()) {
        LOG(ERROR) << "Userspace snapshots requested, but no kernel support is available.";
        return false;
    }
    return true;
}

bool InitializeUringForMerge(struct io_uring* ring, int queue_depth) {
    bool is_taskwrk_supported = KernelSupportsDeferTask();
    struct io_uring_params params = {};

    if (is_taskwrk_supported) {
        params.flags |= (IORING_SETUP_COOP_TASKRUN | IORING_SETUP_SINGLE_ISSUER |
                         IORING_SETUP_DEFER_TASKRUN);
    } else {
        params.flags = 0;
    }

    int ret = io_uring_queue_init_params(queue_depth, ring, &params);
    if (ret) {
        LOG(ERROR) << "io_uring_queue_init_params failed with ret: " << ret;
        return false;
    }

    if (is_taskwrk_supported) {
        unsigned int values[2];
        values[0] = values[1] = 1;
        ret = io_uring_register_iowq_max_workers(ring, values);
        if (ret) {
            LOG(ERROR) << "io_uring_register_iowq_max_workers failed: " << ret;
        }
    }

    return true;
}

}  // namespace snapshot
}  // namespace android
