Add complete support for calling global constructors

kernel/Makefile

@@ -1,4 +1,5 @@
 CC=x86_64-elf-g++
+AS=x86_64-elf-as
 
 WARNING_FLAGS=-Wall -Wextra -pedantic -Wold-style-cast -Wshadow
 CPP_FLAGS=-masm=intel -Iinclude/ -nostdlib -O1 -std=c++11 -fno-exceptions -fno-rtti -ffreestanding -mno-red-zone -mno-mmx -mno-sse -mno-sse2 -mno-sse3 -mno-3dnow $(WARNING_FLAGS)
@@ -10,13 +11,18 @@ KERNEL_O_FILES=kernel.o keyboard.o console.o kernel_utils.o timer.o shell.o util
 CRTBEGIN_OBJ:=$(shell $(CC) $(CFLAGS) -print-file-name=crtbegin.o)
 CRTEND_OBJ:=$(shell $(CC) $(CFLAGS) -print-file-name=crtend.o)
 
-LINK_O_FILES=$(KERNEL_O_FILES)
-
+LINK_O_FILES=crti.o $(CRTBEGIN_OBJ) $(KERNEL_O_FILES) $(CRTEND_OBJ) crtn.o
 
 kernel.bin: $(LINK_O_FILES)
 	$(CC) $(KERNEL_LINK_FLAGS) -o kernel.bin.o $(LINK_O_FILES)
 	objcopy -R .note -R .comment -S -O binary kernel.bin.o kernel.bin
 
+crti.o: src/crti.s
+	$(AS) -c src/crti.s -o crti.o
+
+crtn.o: src/crtn.s
+	$(AS) -c src/crtn.s -o crtn.o
+
 kernel.o: src/kernel.cpp
 	$(CC) $(KERNEL_FLAGS) -c src/kernel.cpp -o kernel.o
 

kernel/include/keyboard.hpp

@@ -14,6 +14,7 @@ namespace keyboard {
 
 const char KEY_ENTER = 0x1C;
 const char KEY_BACKSPACE = 0x0E;
+const char KEY_UP = 0x48;
 
 void install_driver();
 char get_char();

kernel/include/thor.hpp

@@ -16,4 +16,21 @@ void operator delete(void* p);
 void* operator new[](uint64_t size);
 void operator delete[](void* p);
 
+#define ATEXIT_MAX_FUNCS	128
+
+extern "C" {
+
+typedef int uarch_t;
+
+struct atexit_func_entry_t {
+	void (*destructor_func)(void *);
+	void *obj_ptr;
+	void *dso_handle;
+};
+
+int __cxa_atexit(void (*f)(void *), void *objptr, void *dso);
+void __cxa_finalize(void *f);
+
+}
+
 #endif

kernel/include/vector.hpp

@@ -40,6 +40,8 @@ public:
         rhs.data = nullptr;
         rhs._size = 0;
         rhs._capacity = 0;
+
+        return *this;
     }
 
     ~vector(){
@@ -54,6 +56,10 @@ public:
         return _size;
     }
 
+    size_type capacity(){
+        return _capacity;
+    }
+
     //Modifiers
 
     void push_back(value_type& element){

kernel/src/crti.s

@@ -0,0 +1,18 @@
+/* x86_64 crti.s */
+.section .init
+.global _init
+.type _init, @function
+_init:
+push %rbp
+movq %rsp, %rbp
+
+/* gcc will nicely put the contents of crtbegin.o's .init section here. */
+
+.section .fini
+.global _fini
+.type _fini, @function
+_fini:
+push %rbp
+movq %rsp, %rbp
+
+/* gcc will nicely put the contents of crtbegin.o's .fini section here. */

kernel/src/crtn.s

@@ -0,0 +1,11 @@
+/* x86_64 crtn.s */
+
+.section .init
+	/* gcc will nicely put the contents of crtend.o's .init section here. */
+	popq %rbp
+	ret
+
+.section .fini
+	/* gcc will nicely put the contents of crtend.o's .fini section here. */
+	popq %rbp
+	ret

kernel/src/kernel.cpp

@@ -13,12 +13,17 @@
 
 extern "C" {
 
+void _init();
+
 void  __attribute__ ((section ("main_section"))) kernel_main(){
     load_memory_map();
     init_memory_manager();
     install_timer();
     keyboard::install_driver();
     disks::detect_disks();
+
+    _init();
+
     init_shell();
 
     return;

kernel/src/shell.cpp

@@ -14,9 +14,12 @@
 #include "utils.hpp"
 #include "memory.hpp"
 #include "disks.hpp"
+#include "vector.hpp"
 
 namespace {
 
+vector<char*> history;
+
 //Declarations of the different functions
 
 void reboot_command(const char* params);
@@ -84,6 +87,8 @@ void start_shell(){
                 }
 
                 k_print("thor> ");
+            } else if(key == keyboard::KEY_UP){
+                //TODO
             } else if(key == keyboard::KEY_BACKSPACE){
                 if(current_input_length > 0){
                     k_print('\b');
@@ -386,6 +391,7 @@ void init_shell(){
     clear_command(0);
 
     k_print("thor> ");
+    k_print_line(history.capacity());
 
     start_shell();
 }

kernel/src/thor.cpp

@@ -23,3 +23,43 @@ void* operator new[](uint64_t size){
 void operator delete[](void* p){
     return k_free(p);
 }
+
+extern "C" {
+
+atexit_func_entry_t __atexit_funcs[ATEXIT_MAX_FUNCS];
+uarch_t __atexit_func_count = 0;
+
+int __cxa_atexit(void (*f)(void *), void *objptr, void *dso){
+    if (__atexit_func_count >= ATEXIT_MAX_FUNCS) {
+        return -1;
+    }
+    __atexit_funcs[__atexit_func_count].destructor_func = f;
+    __atexit_funcs[__atexit_func_count].obj_ptr = objptr;
+    __atexit_funcs[__atexit_func_count].dso_handle = dso;
+    __atexit_func_count++;
+    return 0; /*I would prefer if functions returned 1 on success, but the ABI says...*/
+}
+
+void __cxa_finalize(void *f){
+    uarch_t i = __atexit_func_count;
+    if (!f){
+        while (i--){
+            if (__atexit_funcs[i].destructor_func){
+                (*__atexit_funcs[i].destructor_func)(__atexit_funcs[i].obj_ptr);
+            }
+        }
+        return;
+    }
+
+    for ( ; i >= 0; --i){
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wpedantic"
+        if (__atexit_funcs[i].destructor_func == f){
+            (*__atexit_funcs[i].destructor_func)(__atexit_funcs[i].obj_ptr);
+            __atexit_funcs[i].destructor_func = 0;
+        }
+#pragma GCC diagnostic pop
+    }
+}
+
+}