ldso/cxx: show symbols names of undefined references

Fixes #2482

repos/base/src/include/base/internal/globals.h

@@ -41,6 +41,9 @@ namespace Genode {
 
 	void destroy_signal_thread();
 
+	void cxx_demangle(char const*, char*, size_t);
+	void cxx_current_exception(char *out, size_t size);
+
 	Id_space<Parent::Client> &env_session_id_space();
 	Env &internal_env();
 }

repos/base/src/lib/cxx/misc.cc

@@ -11,6 +11,10 @@
  * under the terms of the GNU Affero General Public License version 3.
  */
 
+/* libsupc++ includes */
+#include <cxxabi.h>
+
+/* Genode includes */
 #include <base/env.h>
 #include <base/log.h>
 #include <base/stdint.h>
@@ -18,7 +22,8 @@
 #include <base/thread.h>
 #include <util/string.h>
 
-#include <cxxabi.h>
+/* base-internal includes */
+#include <base/internal/globals.h>
 
 
 extern "C" void __cxa_pure_virtual()
@@ -226,3 +231,32 @@ extern "C" __attribute__((weak)) void __stack_chk_fail_local(void)
 {
 	Genode::error("Violated stack boundary");
 }
+
+
+/*******************************
+ ** Demangling of C++ symbols **
+ *******************************/
+
+extern "C" void free(void *);
+
+void Genode::cxx_demangle(char const *symbol, char *out, size_t size)
+{
+	char *demangled_name = __cxxabiv1::__cxa_demangle(symbol, nullptr, nullptr, nullptr);
+	if (demangled_name) {
+		Genode::strncpy(out, demangled_name, size);
+		free(demangled_name);
+	} else {
+		Genode::strncpy(out, symbol, size);
+	}
+}
+
+
+void Genode::cxx_current_exception(char *out, size_t size)
+{
+	std::type_info *t = __cxxabiv1::__cxa_current_exception_type();
+
+	if (!t)
+		return;
+
+	cxx_demangle(t->name(), out, size);
+}

repos/base/src/lib/ldso/include/types.h

@@ -21,6 +21,7 @@
 #include <util/fifo.h>
 #include <util/misc_math.h>
 #include <util/string.h>
+#include <base/internal/globals.h>
 
 namespace Linker {
 
@@ -31,9 +32,49 @@ namespace Linker {
 	 */
 	class Incompatible : Exception  { };
 	class Invalid_file : Exception  { };
-	class Not_found    : Exception  { };
 	class Fatal        : Exception  { };
 
+	class Not_found    : Exception
+	{
+		private:
+
+			enum { CAPACITY = 128 };
+			char _buf[CAPACITY];
+
+		public:
+
+			Not_found() : _buf("<unkown>") { }
+			Not_found(char const *str)
+			{
+				cxx_demangle(str, _buf, CAPACITY);
+			}
+
+			void print(Output &out) const
+			{
+				Genode::print(out, Cstring(_buf, CAPACITY));
+			}
+	};
+
+	class Current_exception
+	{
+		private:
+
+			enum { CAPACITY = 128 };
+			char _buf[CAPACITY];
+
+		public:
+
+			Current_exception() : _buf("<unkown>")
+			{
+				cxx_current_exception(_buf, CAPACITY);
+			}
+
+			void print(Output &out) const
+			{
+				Genode::print(out, Cstring(_buf, CAPACITY));
+			}
+	};
+
 	enum Keep { DONT_KEEP = Shared_object::DONT_KEEP,
 	            KEEP      = Shared_object::KEEP };
 

repos/base/src/lib/ldso/main.cc

@@ -291,8 +291,11 @@ Elf::Addr Ld::jmp_slot(Dependency const &dep, Elf::Size index)
 		Reloc_jmpslot slot(dep, dep.obj().dynamic().pltrel_type(), 
 		                   dep.obj().dynamic().pltrel(), index);
 		return slot.target_addr();
+	} catch (Linker::Not_found &symbol) {
+		error("LD: jump slot relocation failed for symbol: '", symbol, "'");
+		throw;
 	} catch (...) {
-		error("LD: jump slot relocation failed. FATAL!");
+		error("LD: jump slot relocation failed:: '", Current_exception(), "'");
 		throw;
 	}
 
@@ -564,7 +567,7 @@ Elf::Sym const *Linker::lookup_symbol(char const *name, Dependency const &dep,
 		if (binary_ptr && &dep != binary_ptr->first_dep()) {
 			return lookup_symbol(name, *binary_ptr->first_dep(), base, undef, other);
 		} else {
-			throw Not_found();
+			throw Not_found(name);
 		}
 	}
 
@@ -572,7 +575,7 @@ Elf::Sym const *Linker::lookup_symbol(char const *name, Dependency const &dep,
 		log("LD: return ", weak_symbol);
 
 	if (!weak_symbol)
-		throw Not_found();
+		throw Not_found(name);
 
 	*base = weak_base;
 	return weak_symbol;
@@ -661,8 +664,11 @@ void Component::construct(Genode::Env &env)
 	/* load binary and all dependencies */
 	try {
 		binary_ptr = unmanaged_singleton<Binary>(env, *heap(), config.bind());
+	} catch(Linker::Not_found &symbol) {
+		error("LD: symbol not found: '", symbol, "'");
+		throw;
 	} catch (...) {
-		error("LD: failed to load program");
+		error("LD: exception during program load: '", Current_exception(), "'");
 		throw;
 	}
 

repos/base/src/lib/ldso/shared_object.cc

@@ -74,7 +74,17 @@ Genode::Shared_object::Shared_object(Env &env, Allocator &md_alloc,
 				Linker::dump_link_map(to_root(_handle).first_dep()->obj());
 		} catch (...) {  }
 
-	} catch (...) { throw Invalid_file(); }
+	} catch(Linker::Not_found &symbol) {
+		warning("LD: symbol not found: '", symbol, "'");
+		throw Invalid_file();
+
+	} catch (...) {
+		if (Linker::verbose)
+			warning("LD: exception during Shared_object open: "
+			        "'", Current_exception(), "'");
+
+		throw Invalid_file();
+	}
 }