Got basic tty driver & implemented Stack Smash Protector

kernel/src/kernel.c

@@ -1,9 +1,13 @@
 #include <kernel.h>
 #include <tty.h>
 
+#define _hlt()	while (1) __asm__ volatile ("cli; hlt");
+
 __noreturn
 void kmain(void) {
 	tty_init();
-	printk("Hello, World!\n");
+	tty_puts("Hello, World!\n");
+
+	_hlt();
 }
 

kernel/src/ssp.c

@@ -0,0 +1,14 @@
+/*
+ * Stack Smash Protector
+ * Source: https://wiki.osdev.org/Stack_Smashing_Protector
+*/
+#include <kernel.h>
+
+// TODO: Make this randomized
+#define STACK_CHK_GUARD	0x27a1abd8
+
+uintptr_t __stack_chk_guard = STACK_CHK_GUARD;
+__noreturn void __stack_chk_fail(void) {
+	panic("Stack smashing detected!");
+}
+

kernel/src/tty.c

@@ -12,20 +12,52 @@ void tty_init(void) {
 	ctx.row = 0;
 	ctx.col = 0;
 	ctx.attr = 0x07;
-	ctx.buf = (u8*)VGA_MEMORY;
+	ctx.buf = (uint8_t*)VGA_MEMORY;
+	tty_clear();
+}
 
-	for (size_t y = 0; y < VGA_HEIGHT; y++) {
-		for (size_t x = 0; x < VGA_WIDTH; x++) {
-			size_t i = (y * VGA_WIDTH + x) * 2;
-			ctx.buf[i] = ' ';
-			ctx.buf[i + 1] = ctx.attr;
-		}
+void tty_clear(void) {
+	for (int i = 0; i < VGA_WIDTH * VGA_HEIGHT; i++) {
+		ctx.buf[i * 2] = ' ';
+		ctx.buf[i * 2 + 1] = ctx.attr;
 	}
 }
 
-int tty_write(char* buf, size_t len) {}
+void tty_setattr(uint8_t attr) {
+	ctx.attr = attr;
+}
 
-int tty_putc(char c) {}
+// TODO:
+void tty_scroll(void) {
+	ctx.row = 0;
+	ctx.col = 0;
+	tty_clear();
+}
 
-int tty_puts(char* s) {}
+void tty_putat(char c, size_t row, size_t col) {
+	size_t i = row * VGA_WIDTH + col;
+	ctx.buf[i * 2] = c;
+	ctx.buf[i * 2 + 1] = ctx.attr;
+}
+
+void tty_putc(char c) {
+	if (c == '\n') { 
+		ctx.col = 0;
+		ctx.row++;
+		if (ctx.row >= VGA_HEIGHT) tty_scroll();
+		return;
+	}
+
+	tty_putat(c, ctx.row, ctx.col++);
+	if (ctx.col >= VGA_WIDTH) {
+		ctx.col = 0;
+		ctx.row++;
+	}
+
+	if (ctx.row >= VGA_HEIGHT) tty_scroll();
+}
+
+void tty_puts(char* s) {
+	while (*s != '\0') tty_putc(*s++);
+}