be/src/common/stack_trace.cpp

// 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/Common/StackTrace.cpp
// and modified by Doris

#include "common/stack_trace.h"

#include <fmt/format.h>

#if defined(USE_UNWIND) && USE_UNWIND && defined(__x86_64__)
#include <libunwind.h>
#else
#include <execinfo.h>
#endif

#include <atomic>
#include <filesystem>
#include <limits>
#include <map>
#include <mutex>
#include <sstream>
#include <string_view>
#include <unordered_map>

#include "common/config.h"
#include "common/demangle.h"
#include "common/dwarf.h"
#include "common/elf.h"
#include "common/memory_sanitizer.h"
#include "common/symbol_index.h"
#include "exec/common/hex.h"
#include "util/debug_points.h"
#include "util/string_util.h"

namespace {
/// Currently this variable is set up once on server startup.
/// But we use atomic just in case, so it is possible to be modified at runtime.
std::atomic<bool> show_addresses = true;

// #if defined(__ELF__) && !defined(__FreeBSD__)
// void writePointerHex(const void* ptr, std::stringstream& buf) {
//     buf.write("0x", 2);
//     char hex_str[2 * sizeof(ptr)];
//     doris::write_hex_uint_lowercase(reinterpret_cast<uintptr_t>(ptr), hex_str);
//     buf.write(hex_str, 2 * sizeof(ptr));
// }
// #endif

bool shouldShowAddress(const void* addr) {
    /// If the address is less than 4096, most likely it is a nullptr dereference with offset,
    /// and showing this offset is secure nevertheless.
    /// NOTE: 4096 is the page size on x86 and it can be different on other systems,
    /// but for the purpose of this branch, it does not matter.
    if (reinterpret_cast<uintptr_t>(addr) < 4096) {
        return true;
    }

    return show_addresses.load(std::memory_order_relaxed);
}
} // namespace

void StackTrace::setShowAddresses(bool show) {
    show_addresses.store(show, std::memory_order_relaxed);
}

std::string SigsegvErrorString(const siginfo_t& info, [[maybe_unused]] const ucontext_t& context) {
    using namespace std::string_literals;
    std::string address =
            info.si_addr == nullptr
                    ? "NULL pointer"s
                    : (shouldShowAddress(info.si_addr) ? fmt::format("{}", info.si_addr) : ""s);

    const std::string_view access =
#if defined(__x86_64__) && !defined(__FreeBSD__) && !defined(__APPLE__) && !defined(__arm__) && \
        !defined(__powerpc__)
            (context.uc_mcontext.gregs[REG_ERR] & 0x02) ? "write" : "read";
#else
            "";
#endif

    std::string_view message;

    switch (info.si_code) {
    case SEGV_ACCERR:
        message = "Attempted access has violated the permissions assigned to the memory area";
        break;
    case SEGV_MAPERR:
        message = "Address not mapped to object";
        break;
    default:
        message = "Unknown si_code";
        break;
    }

    return fmt::format("Address: {}. Access: {}. {}.", std::move(address), access, message);
}

constexpr std::string_view SigbusErrorString(int si_code) {
    switch (si_code) {
    case BUS_ADRALN:
        return "Invalid address alignment.";
    case BUS_ADRERR:
        return "Non-existent physical address.";
    case BUS_OBJERR:
        return "Object specific hardware error.";

        // Linux specific
#if defined(BUS_MCEERR_AR)
    case BUS_MCEERR_AR:
        return "Hardware memory error: action required.";
#endif
#if defined(BUS_MCEERR_AO)
    case BUS_MCEERR_AO:
        return "Hardware memory error: action optional.";
#endif
    default:
        return "Unknown si_code.";
    }
}

constexpr std::string_view SigfpeErrorString(int si_code) {
    switch (si_code) {
    case FPE_INTDIV:
        return "Integer divide by zero.";
    case FPE_INTOVF:
        return "Integer overflow.";
    case FPE_FLTDIV:
        return "Floating point divide by zero.";
    case FPE_FLTOVF:
        return "Floating point overflow.";
    case FPE_FLTUND:
        return "Floating point underflow.";
    case FPE_FLTRES:
        return "Floating point inexact result.";
    case FPE_FLTINV:
        return "Floating point invalid operation.";
    case FPE_FLTSUB:
        return "Subscript out of range.";
    default:
        return "Unknown si_code.";
    }
}

constexpr std::string_view SigillErrorString(int si_code) {
    switch (si_code) {
    case ILL_ILLOPC:
        return "Illegal opcode.";
    case ILL_ILLOPN:
        return "Illegal operand.";
    case ILL_ILLADR:
        return "Illegal addressing mode.";
    case ILL_ILLTRP:
        return "Illegal trap.";
    case ILL_PRVOPC:
        return "Privileged opcode.";
    case ILL_PRVREG:
        return "Privileged register.";
    case ILL_COPROC:
        return "Coprocessor error.";
    case ILL_BADSTK:
        return "Internal stack error.";
    default:
        return "Unknown si_code.";
    }
}

std::string signalToErrorMessage(int sig, const siginfo_t& info,
                                 [[maybe_unused]] const ucontext_t& context) {
    switch (sig) {
    case SIGSEGV:
        return SigsegvErrorString(info, context);
    case SIGBUS:
        return std::string {SigbusErrorString(info.si_code)};
    case SIGILL:
        return std::string {SigillErrorString(info.si_code)};
    case SIGFPE:
        return std::string {SigfpeErrorString(info.si_code)};
    case SIGTSTP:
        return "This is a signal used for debugging purposes by the user.";
    default:
        return "";
    }
}

static void* getCallerAddress(const ucontext_t& context) {
#if defined(__x86_64__)
    /// Get the address at the time the signal was raised from the RIP (x86-64)
#if defined(__FreeBSD__)
    return reinterpret_cast<void*>(context.uc_mcontext.mc_rip);
#elif defined(__APPLE__)
    return reinterpret_cast<void*>(context.uc_mcontext->__ss.__rip);
#else
    return reinterpret_cast<void*>(context.uc_mcontext.gregs[REG_RIP]);
#endif
#elif defined(__APPLE__) && defined(__aarch64__)
    return reinterpret_cast<void*>(context.uc_mcontext->__ss.__pc);
#elif defined(__FreeBSD__) && defined(__aarch64__)
    return reinterpret_cast<void*>(context.uc_mcontext.mc_gpregs.gp_elr);
#elif defined(__aarch64__)
    return reinterpret_cast<void*>(context.uc_mcontext.pc);
#elif defined(__powerpc64__) && defined(__linux__)
    return reinterpret_cast<void*>(context.uc_mcontext.gp_regs[PT_NIP]);
#elif defined(__powerpc64__) && defined(__FreeBSD__)
    return reinterpret_cast<void*>(context.uc_mcontext.mc_srr0);
#elif defined(__riscv)
    return reinterpret_cast<void*>(context.uc_mcontext.__gregs[REG_PC]);
#elif defined(__s390x__)
    return reinterpret_cast<void*>(context.uc_mcontext.psw.addr);
#else
    return nullptr;
#endif
}

// FIXME: looks like this is used only for Sentry but duplicates the whole algo, maybe replace?
void StackTrace::symbolize(const StackTrace::FramePointers& frame_pointers,
                           [[maybe_unused]] size_t offset, size_t size,
                           StackTrace::Frames& frames) {
#if defined(__ELF__) && !defined(__FreeBSD__)
    auto symbol_index_ptr = doris::SymbolIndex::instance();
    const doris::SymbolIndex& symbol_index = *symbol_index_ptr;
    std::unordered_map<std::string, doris::Dwarf> dwarfs;

    for (size_t i = 0; i < offset; ++i) {
        frames[i].virtual_addr = frame_pointers[i];
    }

    for (size_t i = offset; i < size; ++i) {
        StackTrace::Frame& current_frame = frames[i];
        current_frame.virtual_addr = frame_pointers[i];
        const auto* object = symbol_index.findObject(current_frame.virtual_addr);
        uintptr_t virtual_offset = object ? uintptr_t(object->address_begin) : 0;
        current_frame.physical_addr =
                reinterpret_cast<void*>(uintptr_t(current_frame.virtual_addr) - virtual_offset);

        if (object) {
            current_frame.object = object->name;
            if (std::error_code ec;
                std::filesystem::exists(current_frame.object.value(), ec) && !ec) {
                auto dwarf_it = dwarfs.try_emplace(object->name, object->elf).first;

                doris::Dwarf::LocationInfo location;
                std::vector<doris::Dwarf::SymbolizedFrame> inline_frames;
                if (dwarf_it->second.findAddress(uintptr_t(current_frame.physical_addr), location,
                                                 doris::Dwarf::LocationInfoMode::FAST,
                                                 inline_frames)) {
                    current_frame.file = location.file.toString();
                    current_frame.line = location.line;
                }
            }
        } else {
            current_frame.object = "?";
        }

        if (const auto* symbol = symbol_index.findSymbol(current_frame.virtual_addr)) {
            current_frame.symbol = demangle(symbol->name);
        } else {
            current_frame.symbol = "?";
        }
    }
#else
    for (size_t i = 0; i < size; ++i) frames[i].virtual_addr = frame_pointers[i];
#endif
}

StackTrace::StackTrace(const ucontext_t& signal_context) {
    tryCapture();

    /// This variable from signal handler is not instrumented by Memory Sanitizer.
    __msan_unpoison(&signal_context, sizeof(signal_context));

    void* caller_address = getCallerAddress(signal_context);

    if (size == 0 && caller_address) {
        frame_pointers[0] = caller_address;
        size = 1;
    } else {
        /// Skip excessive stack frames that we have created while finding stack trace.
        for (size_t i = 0; i < size; ++i) {
            const auto frame_address = reinterpret_cast<uintptr_t>(frame_pointers[i]);
            const auto caller_address_value = reinterpret_cast<uintptr_t>(caller_address);
            if (caller_address_value != 0 &&
                (frame_address == caller_address_value ||
                 (caller_address_value < std::numeric_limits<uintptr_t>::max() &&
                  frame_address == caller_address_value + 1))) {
                offset = i;
                break;
            }
        }
    }
}

void StackTrace::tryCapture() {
    int frame_count = 0;
#if defined(USE_UNWIND) && USE_UNWIND && defined(__x86_64__)
    frame_count = unw_backtrace(frame_pointers.data(), capacity);
#else
    frame_count = backtrace(frame_pointers.data(), capacity);
#endif
    size = frame_count > 0 ? static_cast<size_t>(frame_count) : 0;
    if (doris::config::enable_debug_points &&
        doris::DebugPoints::instance()->is_enable("StackTrace::tryCapture.empty_trace")) {
        size = 0;
    }
    __msan_unpoison(frame_pointers.data(), size * sizeof(frame_pointers[0]));
}

/// ClickHouse uses bundled libc++ so type names will be the same on every system thus it's safe to hardcode them
constexpr std::pair<std::string_view, std::string_view> replacements[] = {
        {"::__1", ""},
        {"std::basic_string<char, std::char_traits<char>, std::allocator<char>>", "std::string"}};

std::string collapseNames(std::string&& haystack) {
    // TODO: surely there is a written version already for better in place search&replace
    for (auto [needle, to] : replacements) {
        size_t pos = 0;
        while ((pos = haystack.find(needle, pos)) != std::string::npos) {
            haystack.replace(pos, needle.length(), to);
            pos += to.length();
        }
    }

    return haystack;
}

struct StackTraceRefTriple {
    const StackTrace::FramePointers& pointers;
    size_t offset;
    size_t size;
    std::string_view dwarf_location_info_mode;
};

struct StackTraceTriple {
    StackTrace::FramePointers pointers;
    size_t offset;
    size_t size;
    std::string dwarf_location_info_mode;
};

template <class T>
concept MaybeRef = std::is_same_v<T, StackTraceTriple> || std::is_same_v<T, StackTraceRefTriple>;

constexpr bool operator<(const MaybeRef auto& left, const MaybeRef auto& right) {
    // The same PCs can be rendered with different DWARF detail levels. Keeping the mode in the
    // key prevents a cheap disabled rendering from poisoning a later full rendering, and prevents
    // full file/line detail from leaking into a disabled request.
    return std::tuple {left.pointers, left.size, left.offset,
                       std::string_view(left.dwarf_location_info_mode)} <
           std::tuple {right.pointers, right.size, right.offset,
                       std::string_view(right.dwarf_location_info_mode)};
}

static void toStringEveryLineImpl([[maybe_unused]] const std::string dwarf_location_info_mode,
                                  const StackTraceRefTriple& stack_trace,
                                  std::function<void(std::string_view)> callback) {
    if (stack_trace.size == 0) {
        return callback("<Empty trace>");
    }
#if defined(__ELF__) && !defined(__FreeBSD__)

    using enum doris::Dwarf::LocationInfoMode;
    doris::Dwarf::LocationInfoMode mode;
    auto dwarf_location_info_mode_lower = doris::to_lower(dwarf_location_info_mode);
    if (dwarf_location_info_mode_lower == "disabled") {
        mode = DISABLED;
    } else if (dwarf_location_info_mode_lower == "fast") {
        mode = FAST;
    } else if (dwarf_location_info_mode_lower == "full") {
        mode = FULL;
    } else if (dwarf_location_info_mode_lower == "full_with_inline") {
        mode = FULL_WITH_INLINE;
    } else {
        LOG(INFO) << "invalid LocationInfoMode: " << dwarf_location_info_mode;
        mode = DISABLED;
    }
    auto symbol_index_ptr = doris::SymbolIndex::instance();
    const doris::SymbolIndex& symbol_index = *symbol_index_ptr;
    std::unordered_map<std::string, doris::Dwarf> dwarfs;
    for (size_t i = stack_trace.offset; i < stack_trace.size; ++i) {
        std::vector<doris::Dwarf::SymbolizedFrame> inline_frames;
        const void* virtual_addr = stack_trace.pointers[i];
        const auto* object = symbol_index.findObject(virtual_addr);
        uintptr_t virtual_offset = object ? uintptr_t(object->address_begin) : 0;
        const void* physical_addr =
                reinterpret_cast<const void*>(uintptr_t(virtual_addr) - virtual_offset);

        std::stringstream out;
        out << "\t" << i << "# ";
        if (i < 10) { // for alignment
            out << " ";
        }

        if (const auto* const symbol = symbol_index.findSymbol(virtual_addr)) {
            out << collapseNames(demangle(symbol->name));
        } else {
            out << "?";
        }

        if (std::error_code ec; object && std::filesystem::exists(object->name, ec) && !ec) {
            auto dwarf_it = dwarfs.try_emplace(object->name, object->elf).first;

            doris::Dwarf::LocationInfo location;

            if (dwarf_it->second.findAddress(uintptr_t(physical_addr), location, mode,
                                             inline_frames)) {
                out << " at " << location.file.toString() << ":" << location.line;
            }
        }

        // Do not display the stack address and file name, it is not important.
        // if (shouldShowAddress(physical_addr)) {
        //     out << " @ ";
        //     writePointerHex(physical_addr, out);
        // }

        // out << "  in " << (object ? object->name : "?");

        callback(out.str());

        for (size_t j = 0; j < inline_frames.size(); ++j) {
            const auto& frame = inline_frames[j];
            callback(fmt::format("\t{}.{}. inlined from {}: {}:{}", i, j + 1,
                                 collapseNames(demangle(frame.name)),
                                 frame.location.file.toString(), frame.location.line));
        }
    }
#else
    for (size_t i = stack_trace.offset; i < stack_trace.size; ++i)
        if (const void* const addr = stack_trace.pointers[i]; shouldShowAddress(addr))
            callback(fmt::format("{}. {}", i, addr));
#endif
}

void StackTrace::toStringEveryLine(std::function<void(std::string_view)> callback) const {
    toStringEveryLineImpl("FULL_WITH_INLINE", {frame_pointers, offset, size, "FULL_WITH_INLINE"},
                          std::move(callback));
}

using StackTraceCache = std::map<StackTraceTriple, std::string, std::less<>>;

static StackTraceCache& cacheInstance() {
    static StackTraceCache cache;
    return cache;
}

static std::mutex stacktrace_cache_mutex;

std::string toStringCached(const StackTrace::FramePointers& pointers, size_t offset, size_t size,
                           const std::string& dwarf_location_info_mode) {
    /// Calculation of stack trace text is extremely slow.
    /// We use simple cache because otherwise the server could be overloaded by trash queries.
    /// Note that this cache can grow unconditionally, but practically it should be small.
    std::lock_guard lock {stacktrace_cache_mutex};

    StackTraceCache& cache = cacheInstance();
    const StackTraceRefTriple key {pointers, offset, size, dwarf_location_info_mode};

    if (auto it = cache.find(key); it != cache.end()) {
        return it->second;
    } else {
        std::stringstream out;
        toStringEveryLineImpl(dwarf_location_info_mode, key,
                              [&](std::string_view str) { out << str << '\n'; });

        return cache
                .emplace(StackTraceTriple {pointers, offset, size, dwarf_location_info_mode},
                         out.str())
                .first->second;
    }
}

std::string StackTrace::toString(int start_pointers_index,
                                 const std::string& dwarf_location_info_mode) const {
    // Default delete the first three frame pointers, which are inside the stack_trace.cpp.
    start_pointers_index += 3;
    if (start_pointers_index < 0 || static_cast<size_t>(start_pointers_index) >= size) {
        // Unwind can legitimately return fewer frames than the internal frames we normally hide.
        return toStringCached({}, 0, 0, dwarf_location_info_mode);
    }

    const auto first_frame = static_cast<size_t>(start_pointers_index);
    StackTrace::FramePointers frame_pointers_raw {};
    std::copy(frame_pointers.begin() + first_frame, frame_pointers.end(),
              frame_pointers_raw.begin());
    return toStringCached(frame_pointers_raw, offset > first_frame ? offset - first_frame : 0,
                          size - first_frame, dwarf_location_info_mode);
}

std::string StackTrace::toString(void** frame_pointers_raw, size_t offset, size_t size,
                                 const std::string& dwarf_location_info_mode) {
    __msan_unpoison(frame_pointers_raw, size * sizeof(*frame_pointers_raw));

    StackTrace::FramePointers frame_pointers {};
    std::copy_n(frame_pointers_raw, size, frame_pointers.begin());

    return toStringCached(frame_pointers, offset, size, dwarf_location_info_mode);
}

void StackTrace::createCache() {
    std::lock_guard lock {stacktrace_cache_mutex};
    cacheInstance();
}

void StackTrace::dropCache() {
    std::lock_guard lock {stacktrace_cache_mutex};
    cacheInstance().clear();
}