From 3932ee09e654291275eb2832c1dcb10be5c71f44 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Th=C3=A9ophile=20Bastian?= <contact@tobast.fr>
Date: Wed, 28 Mar 2018 15:33:36 +0200
Subject: [PATCH] Start library: working singleton class schema

---
 Makefile                   | 27 ++++++++++++++++++++++++++
 include/DwarfInterpret.hpp | 35 ++++++++++++++++++++++++++++++++++
 src/DwarfInterpret.cpp     | 39 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 101 insertions(+)
 create mode 100644 Makefile
 create mode 100644 include/DwarfInterpret.hpp
 create mode 100644 src/DwarfInterpret.cpp

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..d020756
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,27 @@
+LIB_DIR=lib
+TARGET=$(LIB_DIR)/libdwarfinterpret.so
+SRC=src/DwarfInterpret.cpp
+
+INCLUDE_DIR=include
+
+CXX=g++
+CXXFLAGS=-Wall -Wextra -O2 --std=c++14
+CXXLIBS=-ldwarfpp -ldwarf -lelf -lc++fileno
+CXXINCLUDE=-I$(INCLUDE_DIR)
+
+
+OBJS = $(SRC:.cpp=.o)
+
+###############################################################################
+
+all: $(TARGET)
+
+$(TARGET): $(OBJS)
+	mkdir -p "$$(dirname "$@")"
+	$(CXX) $(CXXFLAGS) $(CXXLIBS) $(CXXINCLUDE) $^ -shared -o "$@"
+
+%.o: %.cpp
+	$(CXX) $(CXXFLAGS) $(CXXINCLUDE) -fPIC -c "$<" -o "$@"
+
+clean:
+	rm -f $(OBJS) $(TARGET)
diff --git a/include/DwarfInterpret.hpp b/include/DwarfInterpret.hpp
new file mode 100644
index 0000000..2f68908
--- /dev/null
+++ b/include/DwarfInterpret.hpp
@@ -0,0 +1,35 @@
+#pragma once
+
+#include <string>
+#include <memory>
+
+#include <dwarfpp/root.hpp>
+
+class DwarfInterpret {
+    /** Singleton class holding a Dwarf interpret.
+     * Must be first instanciated with the path to the binary being run, with a
+     * call to `instanciate`, and can afterwards be accessed with calls to
+     * `acquire`.
+     */
+
+    public:
+        class NotInstanciated: public std::exception {};
+        class AlreadyInstanciated: public std::exception {};
+
+        DwarfInterpret(DwarfInterpret const&) = delete;
+        void operator=(DwarfInterpret const&) = delete;
+
+        static DwarfInterpret& acquire();
+        static DwarfInterpret& instanciate(const std::string& elf_path);
+
+    private:
+        DwarfInterpret(const std::string& elf_path);
+
+    private: // members
+        static std::unique_ptr<DwarfInterpret> instance;
+
+        dwarf::core::root_die root_die;
+        int elf_machine;
+
+        friend class std::unique_ptr<DwarfInterpret>;
+};
diff --git a/src/DwarfInterpret.cpp b/src/DwarfInterpret.cpp
new file mode 100644
index 0000000..fe2d2bd
--- /dev/null
+++ b/src/DwarfInterpret.cpp
@@ -0,0 +1,39 @@
+#include <DwarfInterpret.hpp>
+
+#include <fstream>
+
+#include <fileno.hpp>
+#include <dwarfpp/lib.hpp>
+#include <dwarfpp/regs.hpp>
+#include <dwarfpp/frame.hpp>
+#include <dwarfpp/attr.hpp>
+#include <dwarfpp/frame.hpp>
+#include <dwarfpp/root.hpp>
+#include <gelf.h>
+
+DwarfInterpret::DwarfInterpret(const std::string& elf_path)
+    : root_die(fileno(std::ifstream(elf_path)))
+{
+	//std::ifstream file_in(elf_path);
+	//root_die = dwarf::core::root_die(fileno(file_in));
+    // FIXME this ^ deserves some checks. But this looks tedious.
+
+	GElf_Ehdr ehdr;
+	GElf_Ehdr *ret = gelf_getehdr(root_die.get_elf(), &ehdr);
+	assert(ret != 0);
+	elf_machine = ehdr.e_machine;
+}
+
+DwarfInterpret& DwarfInterpret::acquire() {
+    if(DwarfInterpret::instance == nullptr)
+        throw NotInstanciated();
+    return *(DwarfInterpret::instance);
+}
+
+DwarfInterpret& DwarfInterpret::instanciate(const std::string& elf_path) {
+    if(DwarfInterpret::instance != nullptr)
+        throw AlreadyInstanciated();
+    DwarfInterpret::instance = std::unique_ptr<DwarfInterpret>(
+            new DwarfInterpret(elf_path));
+    return *(DwarfInterpret::instance);
+}