//

// Copyright 2018 The Abseil Authors.

//

// 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

//

//      https://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 "absl/debugging/internal/examine_stack.h"

#ifndef _WIN32

#include <unistd.h>

#endif

#include "absl/base/config.h"

#ifdef ABSL_HAVE_MMAP

#include <sys/mman.h>

#if defined(MAP_ANON) && !defined(MAP_ANONYMOUS)

#define MAP_ANONYMOUS MAP_ANON

#endif

#endif

#if defined(__linux__) || defined(__APPLE__)

#include <sys/ucontext.h>

#endif

#include <csignal>

#include <cstdio>

#include "absl/base/attributes.h"

#include "absl/base/internal/raw_logging.h"

#include "absl/base/macros.h"

#include "absl/debugging/stacktrace.h"

#include "absl/debugging/symbolize.h"

namespace absl {

ABSL_NAMESPACE_BEGIN

namespace debugging_internal {

namespace {

constexpr int kDefaultDumpStackFramesLimit = 64;

// The %p field width for printf() functions is two characters per byte,

// and two extra for the leading "0x".

constexpr int kPrintfPointerFieldWidth = 2 + 2 * sizeof(void*);

ABSL_CONST_INIT SymbolizeUrlEmitter debug_stack_trace_hook = nullptr;

// Async-signal safe mmap allocator.

void* Allocate(size_t num_bytes) {

#ifdef ABSL_HAVE_MMAP

  void* p = ::mmap(nullptr, num_bytes, PROT_READ | PROT_WRITE,

                   MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);

  return p == MAP_FAILED ? nullptr : p;

#else

  (void)num_bytes;

  return nullptr;

#endif  // ABSL_HAVE_MMAP

}

void Deallocate(void* p, size_t size) {

#ifdef ABSL_HAVE_MMAP

  ::munmap(p, size);

#else

  (void)p;

  (void)size;

#endif  // ABSL_HAVE_MMAP

}

// Print a program counter only.

void DumpPC(OutputWriter* writer, void* writer_arg, void* const pc,

            const char* const prefix) {

  char buf[100];

  snprintf(buf, sizeof(buf), "%s@ %*p\n", prefix, kPrintfPointerFieldWidth, pc);

  writer(buf, writer_arg);

}

// Print a program counter and the corresponding stack frame size.

void DumpPCAndFrameSize(OutputWriter* writer, void* writer_arg, void* const pc,

                        int framesize, const char* const prefix) {

  char buf[100];

  if (framesize <= 0) {

    snprintf(buf, sizeof(buf), "%s@ %*p  (unknown)\n", prefix,

             kPrintfPointerFieldWidth, pc);

  } else {

    snprintf(buf, sizeof(buf), "%s@ %*p  %9d\n", prefix,

             kPrintfPointerFieldWidth, pc, framesize);

  }

  writer(buf, writer_arg);

}

// Print a program counter and the corresponding symbol.

void DumpPCAndSymbol(OutputWriter* writer, void* writer_arg, void* const pc,

                     const char* const prefix) {

  char tmp[1024];

  const char* symbol = "(unknown)";

  // Symbolizes the previous address of pc because pc may be in the

  // next function.  The overrun happens when the function ends with

  // a call to a function annotated noreturn (e.g. CHECK).

  // If symbolization of pc-1 fails, also try pc on the off-chance

  // that we crashed on the first instruction of a function (that

  // actually happens very often for e.g. __restore_rt).

  const uintptr_t prev_pc = reinterpret_cast<uintptr_t>(pc) - 1;

  if (absl::Symbolize(reinterpret_cast<const char*>(prev_pc), tmp,

                      sizeof(tmp)) ||

      absl::Symbolize(pc, tmp, sizeof(tmp))) {

    symbol = tmp;

  }

  char buf[1024];

  snprintf(buf, sizeof(buf), "%s@ %*p  %s\n", prefix, kPrintfPointerFieldWidth,

           pc, symbol);

  writer(buf, writer_arg);

}

// Print a program counter, its stack frame size, and its symbol name.

// Note that there is a separate symbolize_pc argument. Return addresses may be

// at the end of the function, and this allows the caller to back up from pc if

// appropriate.

void DumpPCAndFrameSizeAndSymbol(OutputWriter* writer, void* writer_arg,

                                 void* const pc, void* const symbolize_pc,

                                 int framesize, const char* const prefix) {

  char tmp[1024];

  const char* symbol = "(unknown)";

  if (absl::Symbolize(symbolize_pc, tmp, sizeof(tmp))) {

    symbol = tmp;

  }

  char buf[1024];

  if (framesize <= 0) {

    snprintf(buf, sizeof(buf), "%s@ %*p  (unknown)  %s\n", prefix,

             kPrintfPointerFieldWidth, pc, symbol);

  } else {

    snprintf(buf, sizeof(buf), "%s@ %*p  %9d  %s\n", prefix,

             kPrintfPointerFieldWidth, pc, framesize, symbol);

  }

  writer(buf, writer_arg);

}

}  // namespace

void RegisterDebugStackTraceHook(SymbolizeUrlEmitter hook) {

  debug_stack_trace_hook = hook;

}

SymbolizeUrlEmitter GetDebugStackTraceHook() { return debug_stack_trace_hook; }

// Returns the program counter from signal context, nullptr if

// unknown. vuc is a ucontext_t*. We use void* to avoid the use of

// ucontext_t on non-POSIX systems.

void* GetProgramCounter(void* const vuc) {

#ifdef __linux__

  if (vuc != nullptr) {

    ucontext_t* context = reinterpret_cast<ucontext_t*>(vuc);

#if defined(__aarch64__)

    return reinterpret_cast<void*>(context->uc_mcontext.pc);

#elif defined(__alpha__)

    return reinterpret_cast<void*>(context->uc_mcontext.sc_pc);

#elif defined(__arm__)

    return reinterpret_cast<void*>(context->uc_mcontext.arm_pc);

#elif defined(__hppa__)

    return reinterpret_cast<void*>(context->uc_mcontext.sc_iaoq[0]);

#elif defined(__i386__)

    if (14 < ABSL_ARRAYSIZE(context->uc_mcontext.gregs))

      return reinterpret_cast<void*>(context->uc_mcontext.gregs[14]);

#elif defined(__ia64__)

    return reinterpret_cast<void*>(context->uc_mcontext.sc_ip);

#elif defined(__m68k__)

    return reinterpret_cast<void*>(context->uc_mcontext.gregs[16]);

#elif defined(__mips__)

    return reinterpret_cast<void*>(context->uc_mcontext.pc);

#elif defined(__powerpc64__)

    return reinterpret_cast<void*>(context->uc_mcontext.gp_regs[32]);

#elif defined(__powerpc__)

    return reinterpret_cast<void*>(context->uc_mcontext.uc_regs->gregs[32]);

#elif defined(__riscv)

    return reinterpret_cast<void*>(context->uc_mcontext.__gregs[REG_PC]);

#elif defined(__s390__) && !defined(__s390x__)

    return reinterpret_cast<void*>(context->uc_mcontext.psw.addr & 0x7fffffff);

#elif defined(__s390__) && defined(__s390x__)

    return reinterpret_cast<void*>(context->uc_mcontext.psw.addr);

#elif defined(__sh__)

    return reinterpret_cast<void*>(context->uc_mcontext.pc);

#elif defined(__sparc__) && !defined(__arch64__)

    return reinterpret_cast<void*>(context->uc_mcontext.gregs[19]);

#elif defined(__sparc__) && defined(__arch64__)

    return reinterpret_cast<void*>(context->uc_mcontext.mc_gregs[19]);

#elif defined(__x86_64__)

    if (16 < ABSL_ARRAYSIZE(context->uc_mcontext.gregs))

      return reinterpret_cast<void*>(context->uc_mcontext.gregs[16]);

#elif defined(__e2k__)

    return reinterpret_cast<void*>(context->uc_mcontext.cr0_hi);

#elif defined(__loongarch__)

    return reinterpret_cast<void*>(context->uc_mcontext.__pc);

#else

#error "Undefined Architecture."

#endif

  }

#elif defined(__APPLE__)

  if (vuc != nullptr) {

    ucontext_t* signal_ucontext = reinterpret_cast<ucontext_t*>(vuc);

#if defined(__aarch64__)

    return reinterpret_cast<void*>(

        __darwin_arm_thread_state64_get_pc(signal_ucontext->uc_mcontext->__ss));

#elif defined(__arm__)

#if __DARWIN_UNIX03

    return reinterpret_cast<void*>(signal_ucontext->uc_mcontext->__ss.__pc);

#else

    return reinterpret_cast<void*>(signal_ucontext->uc_mcontext->ss.pc);

#endif

#elif defined(__i386__)

#if __DARWIN_UNIX03

    return reinterpret_cast<void*>(signal_ucontext->uc_mcontext->__ss.__eip);

#else

    return reinterpret_cast<void*>(signal_ucontext->uc_mcontext->ss.eip);

#endif

#elif defined(__x86_64__)

#if __DARWIN_UNIX03

    return reinterpret_cast<void*>(signal_ucontext->uc_mcontext->__ss.__rip);

#else

    return reinterpret_cast<void*>(signal_ucontext->uc_mcontext->ss.rip);

#endif

#endif

  }

#elif defined(__akaros__)

  auto* ctx = reinterpret_cast<struct user_context*>(vuc);

  return reinterpret_cast<void*>(get_user_ctx_pc(ctx));

#endif

  static_cast<void>(vuc);

  return nullptr;

}

void DumpPCAndFrameSizesAndStackTrace(void* const pc, void* const stack[],

                                      int frame_sizes[], int depth,

                                      int min_dropped_frames,

                                      bool symbolize_stacktrace,

                                      OutputWriter* writer, void* writer_arg) {

  if (pc != nullptr) {

    // We don't know the stack frame size for PC, use 0.

    if (symbolize_stacktrace) {

      DumpPCAndFrameSizeAndSymbol(writer, writer_arg, pc, pc, 0, "PC: ");

    } else {

      DumpPCAndFrameSize(writer, writer_arg, pc, 0, "PC: ");

    }

  }

  for (int i = 0; i < depth; i++) {

    if (symbolize_stacktrace) {

      // Pass the previous address of pc as the symbol address because pc is a

      // return address, and an overrun may occur when the function ends with a

      // call to a function annotated noreturn (e.g. CHECK). Note that we don't

      // do this for pc above, as the adjustment is only correct for return

      // addresses.

      DumpPCAndFrameSizeAndSymbol(writer, writer_arg, stack[i],

                                  reinterpret_cast<char*>(stack[i]) - 1,

                                  frame_sizes[i], "    ");

    } else {

      DumpPCAndFrameSize(writer, writer_arg, stack[i], frame_sizes[i], "    ");

    }

  }

  if (min_dropped_frames > 0) {

    char buf[100];

    snprintf(buf, sizeof(buf), "    @ ... and at least %d more frames\n",

             min_dropped_frames);

    writer(buf, writer_arg);

  }

}

// Dump current stack trace as directed by writer.

// Make sure this function is not inlined to avoid skipping too many top frames.

ABSL_ATTRIBUTE_NOINLINE

void DumpStackTrace(int min_dropped_frames, int max_num_frames,

                    bool symbolize_stacktrace, OutputWriter* writer,

                    void* writer_arg) {

  // Print stack trace

  void* stack_buf[kDefaultDumpStackFramesLimit];

  void** stack = stack_buf;

  int num_stack = kDefaultDumpStackFramesLimit;

  size_t allocated_bytes = 0;

  if (num_stack >= max_num_frames) {

    // User requested fewer frames than we already have space for.

    num_stack = max_num_frames;

  } else {

    const size_t needed_bytes =

        static_cast<size_t>(max_num_frames) * sizeof(stack[0]);

    void* p = Allocate(needed_bytes);

    if (p != nullptr) {  // We got the space.

      num_stack = max_num_frames;

      stack = reinterpret_cast<void**>(p);

      allocated_bytes = needed_bytes;

    }

  }

  int depth = absl::GetStackTrace(stack, num_stack, min_dropped_frames + 1);

  for (int i = 0; i < depth; i++) {

    if (symbolize_stacktrace) {

      DumpPCAndSymbol(writer, writer_arg, stack[static_cast<size_t>(i)],

                      "    ");

    } else {

      DumpPC(writer, writer_arg, stack[static_cast<size_t>(i)], "    ");

    }

  }

  auto hook = GetDebugStackTraceHook();

  if (hook != nullptr) {

    (*hook)(stack, depth, writer, writer_arg);

  }

  if (allocated_bytes != 0) Deallocate(stack, allocated_bytes);

}

}  // namespace debugging_internal

ABSL_NAMESPACE_END

}  // namespace absl