// 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.

// This file is copied from

// https://github.com/ClickHouse/ClickHouse/blob/master/src/base/phdr_cache.cpp

// and modified by Doris

#include "common/phdr_cache.h"

#if defined(__clang__)

#pragma clang diagnostic ignored "-Wreserved-identifier"

#endif

/// This code was based on the code by Fedor Korotkiy https://www.linkedin.com/in/fedor-korotkiy-659a1838/

#if defined(__linux__) && !defined(THREAD_SANITIZER) && !defined(USE_MUSL)

#define USE_PHDR_CACHE 1

#endif

/// Thread Sanitizer uses dl_iterate_phdr function on initialization and fails if we provide our own.

#ifdef USE_PHDR_CACHE

#if defined(__clang__)

#pragma clang diagnostic ignored "-Wreserved-id-macro"

#pragma clang diagnostic ignored "-Wunused-macros"

#endif

#define __msan_unpoison(X, Y) // NOLINT

#if defined(__clang__) && defined(__has_feature)

#if __has_feature(memory_sanitizer)

#undef __msan_unpoison

#include <sanitizer/msan_interface.h>

#endif

#endif

#include <dlfcn.h>

#include <link.h>

#include <atomic>

#include <cstddef>

#include <stdexcept>

#include <vector>

namespace {

// This is adapted from

// https://github.com/scylladb/seastar/blob/master/core/exception_hacks.hh

// https://github.com/scylladb/seastar/blob/master/core/exception_hacks.cc

using DLIterateFunction = int (*)(int (*callback)(dl_phdr_info* info, size_t size, void* data),

                                  void* data);

DLIterateFunction getOriginalDLIteratePHDR() {

    void* func = dlsym(RTLD_NEXT, "dl_iterate_phdr");

    if (!func) {

        throw std::runtime_error("Cannot find dl_iterate_phdr function with dlsym");

    }

    return reinterpret_cast<DLIterateFunction>(func);

}

using PHDRCache = std::vector<dl_phdr_info>;

std::atomic<PHDRCache*> phdr_cache {};

// This flag is flipped inside the stack-trace signal handler. Force a static TLS access model so

// reading it from our dl_iterate_phdr interposer does not call into the dynamic loader's TLS path.

__thread bool use_phdr_cache __attribute__((tls_model("initial-exec"))) = false;

} // namespace

extern "C"

#ifndef __clang__

        [[gnu::visibility("default")]] [[gnu::externally_visible]]

#endif

        int

        dl_iterate_phdr(int (*callback)(dl_phdr_info* info, size_t size, void* data), void* data) {

    if (!use_phdr_cache) {

        return getOriginalDLIteratePHDR()(callback, data);

    }

    auto* current_phdr_cache = phdr_cache.load(std::memory_order_acquire);

    if (!current_phdr_cache) {

        return getOriginalDLIteratePHDR()(callback, data);

    }

    int result = 0;

    for (auto& entry : *current_phdr_cache) {

        result = callback(&entry, offsetof(dl_phdr_info, dlpi_adds), data);

        if (result != 0) {

            break;

        }

    }

    return result;

}

#include "util/debug/leak_annotations.h"

void updatePHDRCache() {

    // Fill out ELF header cache for access without locking.

    // Old snapshots are intentionally kept alive because another thread may already be unwinding

    // through the previous cache when a Doris-controlled dlopen/dlclose refreshes this one.

    PHDRCache* new_phdr_cache = new PHDRCache;

    getOriginalDLIteratePHDR()(

            [](dl_phdr_info* info, size_t /*size*/, void* data) {

                // `info` is created by dl_iterate_phdr, which is a non-instrumented

                // libc function, so we have to unpoison it manually.

                __msan_unpoison(info, sizeof(*info));

                reinterpret_cast<PHDRCache*>(data)->push_back(*info);

                return 0;

            },

            new_phdr_cache);

    phdr_cache.store(new_phdr_cache, std::memory_order_release);

    /// Memory is intentionally leaked.

    ANNOTATE_LEAKING_OBJECT_PTR(new_phdr_cache);

}

bool hasPHDRCache() {

    return phdr_cache.load(std::memory_order_acquire) != nullptr;

}

ScopedPHDRCacheRead::ScopedPHDRCacheRead() : _previous(use_phdr_cache) {

    use_phdr_cache = true;

}

ScopedPHDRCacheRead::~ScopedPHDRCacheRead() {

    use_phdr_cache = _previous;

}

#else

void updatePHDRCache() {}

#if defined(USE_MUSL)

/// With statically linked with musl, dl_iterate_phdr is immutable.

bool hasPHDRCache() {

    return true;

}

#else

bool hasPHDRCache() {

    return false;

}

#endif

ScopedPHDRCacheRead::ScopedPHDRCacheRead() = default;

ScopedPHDRCacheRead::~ScopedPHDRCacheRead() = default;

#endif