text: //  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
  //  This source code is licensed under the BSD-style license found in the
  //  LICENSE file in the root directory of this source tree. An additional grant
  //  of patent rights can be found in the PATENTS file in the same directory.
  //  This source code is also licensed under the GPLv2 license found in the
  //  COPYING file in the root directory of this source tree.
  //
  #include "port/stack_trace.h"
  
  #if defined(ROCKSDB_LITE) || !(defined(ROCKSDB_BACKTRACE) || defined(OS_MACOSX)) || \
      defined(CYGWIN) || defined(OS_FREEBSD) || defined(OS_SOLARIS)
  
  // noop
  
  namespace rocksdb {
  namespace port {
  void InstallStackTraceHandler() {}
  void PrintStack(int first_frames_to_skip) {}
  }  // namespace port
  }  // namespace rocksdb
  
  #else
  
  #include <execinfo.h>
  #include <signal.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <unistd.h>
  #include <cxxabi.h>
  
  namespace rocksdb {
  namespace port {
  
  namespace {
  
  #ifdef OS_LINUX
  const char* GetExecutableName() {
    static char name[1024];
  
    char link[1024];
    snprintf(link, sizeof(link), "/proc/%d/exe", getpid());
    auto read = readlink(link, name, sizeof(name) - 1);
    if (-1 == read) {
      return nullptr;
    } else {
      name[read] = 0;
      return name;
    }
  }
  
  void PrintStackTraceLine(const char* symbol, void* frame) {
    static const char* executable = GetExecutableName();
    if (symbol) {
      fprintf(stderr, "%s ", symbol);
    }
    if (executable) {
      // out source to addr2line, for the address translation
      const int kLineMax = 256;
      char cmd[kLineMax];
      snprintf(cmd, kLineMax, "addr2line %p -e %s -f -C 2>&1", frame, executable);
      auto f = popen(cmd, "r");
      if (f) {
        char line[kLineMax];
        while (fgets(line, sizeof(line), f)) {
          line[strlen(line) - 1] = 0;  // remove newline
          fprintf(stderr, "%s\t", line);
        }
        pclose(f);
      }
    } else {
      fprintf(stderr, " %p", frame);
    }
  
    fprintf(stderr, "\n");
  }
  #elif defined(OS_MACOSX)
  
  void PrintStackTraceLine(const char* symbol, void* frame) {
    static int pid = getpid();
    // out source to atos, for the address translation
    const int kLineMax = 256;
    char cmd[kLineMax];
    snprintf(cmd, kLineMax, "xcrun atos %p -p %d  2>&1", frame, pid);
    auto f = popen(cmd, "r");
    if (f) {
      char line[kLineMax];
      while (fgets(line, sizeof(line), f)) {
        line[strlen(line) - 1] = 0;  // remove newline
        fprintf(stderr, "%s\t", line);
      }
      pclose(f);
    } else if (symbol) {
      fprintf(stderr, "%s ", symbol);
    }
  
    fprintf(stderr, "\n");
  }
  
  #endif
  
  }  // namespace
  
  void PrintStack(int first_frames_to_skip) {
    const int kMaxFrames = 100;
    void* frames[kMaxFrames];
  
    auto num_frames = backtrace(frames, kMaxFrames);
    auto symbols = backtrace_symbols(frames, num_frames);
  
    for (int i = first_frames_to_skip; i < num_frames; ++i) {
      fprintf(stderr, "#%-2d  ", i - first_frames_to_skip);
      PrintStackTraceLine((symbols != nullptr) ? symbols[i] : nullptr, frames[i]);
    }
    free(symbols);
  }
  
  static void StackTraceHandler(int sig) {
    // reset to default handler
    signal(sig, SIG_DFL);
    fprintf(stderr, "Received signal %d (%s)\n", sig, strsignal(sig));
    // skip the top three signal handler related frames
    PrintStack(3);
    // re-signal to default handler (so we still get core dump if needed...)
    raise(sig);
  }
  
  void InstallStackTraceHandler() {
    // just use the plain old signal as it's simple and sufficient
    // for this use case
    signal(SIGILL, StackTraceHandler);
    signal(SIGSEGV, StackTraceHandler);
    signal(SIGBUS, StackTraceHandler);
    signal(SIGABRT, StackTraceHandler);
  }
  
  }  // namespace port
  }  // namespace rocksdb
  
  #endif
  