src: unify native symbol inspection code

Use a single file, and a single interface, for inspecting symbols in the current process for debugging. PR-URL: #21238 Reviewed-By: Tiancheng "Timothy" Gu <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Gus Caplan <[email protected]> Reviewed-By: Ben Noordhuis <[email protected]> Reviewed-By: Benjamin Gruenbaum <[email protected]> Reviewed-By: Colin Ihrig <[email protected]>

Author: addaleax

node.gyp

@@ -316,6 +316,7 @@
 'src/cares_wrap.cc',
 'src/connection_wrap.cc',
 'src/connect_wrap.cc',
+'src/debug_utils.cc',
 'src/env.cc',
 'src/exceptions.cc',
 'src/fs_event_wrap.cc',
@@ -495,9 +496,6 @@
 'defines': [ 'HAVE_INSPECTOR=0' ]
  }],
  [ 'OS=="win"',{
-'sources': [
-'src/backtrace_win32.cc',
- ],
 'conditions': [
  [ 'node_intermediate_lib_type!="static_library"',{
 'sources': [
@@ -506,8 +504,6 @@
  }],
  ],
 'libraries': [ '-lpsapi.lib' ]
- },{# POSIX
-'sources': [ 'src/backtrace_posix.cc' ],
  }],
  [ 'node_use_etw=="true"',{
 'defines': [ 'HAVE_ETW=1' ],

src/backtrace_posix.cc

@@ -0,0 +1,180 @@
+#include"debug_utils.h"
+#include"node_internals.h"
+
+#ifdef __POSIX__
+#if defined(__linux__)
+#include<features.h>
+#endif
+
+#if defined(__linux__) && !defined(__GLIBC__) || \
+defined(__UCLIBC__) || \
+ defined(_AIX)
+#defineHAVE_EXECINFO_H0
+#else
+#defineHAVE_EXECINFO_H1
+#endif
+
+#if HAVE_EXECINFO_H
+#include<cxxabi.h>
+#include<dlfcn.h>
+#include<execinfo.h>
+#include<unistd.h>
+#include<sys/mman.h>
+#include<stdio.h>
+#endif
+
+#else// __POSIX__
+
+#include<windows.h>
+#include<dbghelp.h>
+
+#endif// __POSIX__
+
+namespacenode{
+
+#ifdef __POSIX__
+#if HAVE_EXECINFO_H
+classPosixSymbolDebuggingContextfinal : public NativeSymbolDebuggingContext{
+public:
+PosixSymbolDebuggingContext() : pagesize_(getpagesize()){}
+
+ SymbolInfo LookupSymbol(void* address) override{
+ Dl_info info;
+constbool have_info = dladdr(address, &info);
+ SymbolInfo ret;
+if (!have_info)
+return ret;
+
+if (info.dli_sname != nullptr){
+if (char* demangled = abi::__cxa_demangle(info.dli_sname, 0, 0, 0)){
+ ret.name = demangled;
+free(demangled);
+ } else{
+ ret.name = info.dli_sname;
+ }
+ }
+
+if (info.dli_fname != nullptr){
+ ret.filename = info.dli_fname;
+ }
+
+return ret;
+ }
+
+boolIsMapped(void* address) override{
+void* page_aligned = reinterpret_cast<void*>(
+reinterpret_cast<uintptr_t>(address) & ~(pagesize_ - 1));
+returnmsync(page_aligned, pagesize_, MS_ASYNC) == 0;
+ }
+
+intGetStackTrace(void** frames, int count) override{
+returnbacktrace(frames, count);
+ }
+
+private:
+uintptr_t pagesize_;
+};
+
+std::unique_ptr<NativeSymbolDebuggingContext>
+NativeSymbolDebuggingContext::New(){
+return std::unique_ptr<NativeSymbolDebuggingContext>(
+newPosixSymbolDebuggingContext());
+}
+
+#else// HAVE_EXECINFO_H
+
+std::unique_ptr<NativeSymbolDebuggingContext>
+NativeSymbolDebuggingContext::New(){
+return std::unique_ptr<NativeSymbolDebuggingContext>(
+newNativeSymbolDebuggingContext());
+}
+
+#endif// HAVE_EXECINFO_H
+
+#else// __POSIX__
+
+classWin32SymbolDebuggingContextfinal : public NativeSymbolDebuggingContext{
+public:
+Win32SymbolDebuggingContext(){
+ current_process_ = GetCurrentProcess();
+USE(SymInitialize(process, nullptr, true));
+ }
+
+~Win32SymbolDebuggingContext(){
+USE(SymCleanup(process));
+ }
+
+ SymbolInfo LookupSymbol(void* address) override{
+// Ref: https://msdn.microsoft.com/en-en/library/windows/desktop/ms680578(v=vs.85).aspx
+char info_buf[sizeof(SYMBOL_INFO) + MAX_SYM_NAME];
+ SYMBOL_INFO* info = reinterpret_cast<SYMBOL_INFO*>(info_buf);
+char demangled[MAX_SYM_NAME];
+
+ info->MaxNameLen = MAX_SYM_NAME;
+ info->SizeOfStruct = sizeof(SYMBOL_INFO);
+
+ SymbolInfo ret;
+constbool have_info = SymFromAddr(process,
+reinterpret_cast<DWORD64>(address),
+nullptr,
+ info);
+if (have_info && strlen(info->Name) == 0){
+if (UnDecorateSymbolName(info->Name,
+ demangled_,
+sizeof(demangled_),
+ UNDNAME_COMPLETE)){
+ ret.name = demangled_;
+ } else{
+ ret.name = info->Name;
+ }
+ }
+
+return ret;
+ }
+
+boolIsMapped(void* address) override{
+ MEMORY_BASIC_INFORMATION info;
+
+if (VirtualQuery(address, &info, sizeof(info)) != info)
+returnfalse;
+
+return info.State == MEM_COMMIT && info.Protect != 0;
+ }
+
+intGetStackTrace(void** frames, int count) override{
+returnCaptureStackBackTrace(0, count, frames, nullptr);
+ }
+
+private:
+ HANDLE current_process_;
+};
+
+NativeSymbolDebuggingContext::New(){
+return std::unique_ptr<NativeSymbolDebuggingContext>(
+newWin32SymbolDebuggingContext());
+}
+
+#endif// __POSIX__
+
+std::string NativeSymbolDebuggingContext::SymbolInfo::Display() const{
+ std::string ret = name;
+if (!filename.empty()){
+ ret += " [";
+ ret += filename;
+ ret += ']';
+ }
+return ret;
+}
+
+voidDumpBacktrace(FILE* fp){
+auto sym_ctx = NativeSymbolDebuggingContext::New();
+void* frames[256];
+constint size = sym_ctx->GetStackTrace(frames, arraysize(frames));
+for (int i = 1; i < size; i += 1){
+void* frame = frames[i];
+fprintf(fp, "%2d: %p %s\n",
+ i, frame, sym_ctx->LookupSymbol(frame).Display().c_str());
+ }
+}
+
+} // namespace node

src/backtrace_win32.cc

@@ -84,6 +84,24 @@ inline void FORCE_INLINE Debug(AsyncWrap* async_wrap,
 Debug(async_wrap, format.c_str(), std::forward<Args>(args)...);
 }
 
+// Debug helper for inspecting the currently running `node` executable.
+classNativeSymbolDebuggingContext{
+public:
+static std::unique_ptr<NativeSymbolDebuggingContext> New();
+
+classSymbolInfo{
+public:
+ std::string name;
+ std::string filename;
+
+ std::string Display() const;
+ };
+
+virtual~NativeSymbolDebuggingContext(){}
+virtual SymbolInfo LookupSymbol(void* address){return{"", "" }}
+virtualboolIsMapped(void* address){returnfalse}
+virtualintGetStackTrace(void** frames, int count){return0}
+};
 
 } // namespace node