libstdc++: Add error handler for <stacktrace>

Not providing an error handler results in a null pointer dereference
when an error occurs.

Co-authored-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:

	* include/std/stacktrace (stacktrace_entry::_S_err_handler): New
	static function.
	(stacktrace_entry, basic_stacktrace): Pass &_S_err_handler to
	all calls to libbacktrace.

diff --git a/libstdc++-v3/include/std/stacktrace b/libstdc++-v3/include/std/stacktrace
index e7cbbee..ec3335e 100644 (file)
--- a/libstdc++-v3/include/std/stacktrace
+++ b/libstdc++-v3/include/std/stacktrace
@@ -155,11 +155,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
     template<typename _Allocator> friend class basic_stacktrace;
 
+    static void _S_err_handler(void*, const char*, int) { }
+
     static __glibcxx_backtrace_state*
     _S_init()
     {
       static __glibcxx_backtrace_state* __state
-       = __glibcxx_backtrace_create_state(nullptr, 1, nullptr, nullptr);
+       = __glibcxx_backtrace_create_state(nullptr, 1, _S_err_handler, nullptr);
       return __state;
     }
 
@@ -192,7 +194,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
          return __function != nullptr;
       };
       const auto __state = _S_init();
-      if (::__glibcxx_backtrace_pcinfo(__state, _M_pc, +__cb, nullptr, &__data))
+      if (::__glibcxx_backtrace_pcinfo(__state, _M_pc, +__cb, _S_err_handler,
+                                      &__data))
        return true;
       if (__desc && __desc->empty())
        {
@@ -201,8 +204,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
              if (__symname)
                *static_cast<_Data*>(__data)->_M_desc = _S_demangle(__symname);
          };
-         if (::__glibcxx_backtrace_syminfo(__state, _M_pc, +__cb2, nullptr,
-                                           &__data))
+         if (::__glibcxx_backtrace_syminfo(__state, _M_pc, +__cb2,
+                                           _S_err_handler, &__data))
            return true;
        }
       return false;
@@ -252,7 +255,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        if (auto __cb = __ret._M_prepare()) [[likely]]
          {
            auto __state = stacktrace_entry::_S_init();
-           if (__glibcxx_backtrace_simple(__state, 1, __cb, nullptr,
+           if (__glibcxx_backtrace_simple(__state, 1, __cb,
+                                          stacktrace_entry::_S_err_handler,
                                           std::__addressof(__ret)))
              __ret._M_clear();
          }
@@ -270,7 +274,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        if (auto __cb = __ret._M_prepare()) [[likely]]
          {
            auto __state = stacktrace_entry::_S_init();
-           if (__glibcxx_backtrace_simple(__state, __skip + 1, __cb, nullptr,
+           if (__glibcxx_backtrace_simple(__state, __skip + 1, __cb,
+                                          stacktrace_entry::_S_err_handler,
                                           std::__addressof(__ret)))
              __ret._M_clear();
          }
@@ -294,7 +299,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
          {
            auto __state = stacktrace_entry::_S_init();
            int __err = __glibcxx_backtrace_simple(__state, __skip + 1, __cb,
-                                                  nullptr,
+                                                  stacktrace_entry::_S_err_handler,
                                                   std::__addressof(__ret));
            if (__err < 0)
              __ret._M_clear();