syscalls: implement basic syscall architecture

src/arch/i686/interrupts/mod.rs

@@ -4,6 +4,7 @@ mod exceptions;
 pub mod idt;
 mod irq;
 mod pic;
+mod software;
 
 #[inline(always)]
 pub unsafe fn init()
@@ -86,6 +87,10 @@ pub unsafe extern "C" fn interrupt_handler(state: &State)
 		{
 			irq::handler(state);
 		}
+		0x30 | 0x80 =>
+		{
+			software::handler(state);
+		}
 		_ =>
 		{
 			crate::serial_println!("Got unhandled interrupt {:02x}", interrupt);

src/arch/i686/interrupts/software.rs

@@ -0,0 +1,51 @@
+use super::State;
+
+use core::slice;
+
+#[derive(Copy, Clone)]
+pub struct Syscall
+{
+	name: &'static str,
+	pub handler: unsafe fn(u32, u32, u32)
+}
+
+pub static SYSCALLS: [Syscall; 2] =
+[
+	Syscall {name: "read", handler: sys_dummy},
+	Syscall {name: "write", handler: sys_write}
+];
+
+
+pub unsafe fn handler(state: &State)
+{
+	syscall(state.eax, state.ebx, state.ecx, state.edx);
+}
+
+unsafe fn syscall(syscall_number: u32, arg1: u32, arg2: u32, arg3: u32)
+{
+	if (syscall_number as usize) < SYSCALLS.len()
+	{
+		let syscall = SYSCALLS[syscall_number as usize];
+		crate::serial_println!("Called syscall {}({}, {}, {})", syscall.name, arg1, arg2, arg3);
+		(syscall.handler)(arg1, arg2, arg3);
+	}
+	else
+	{
+		panic!("Invalid syscall {}({}, {}, {})", syscall_number, arg1, arg2, arg3);
+	}
+}
+
+unsafe fn sys_dummy(_arg1: u32, _arg2: u32, _arg3: u32)
+{
+
+}
+
+unsafe fn sys_write(_file_descriptor: u32, buffer: u32, len: u32)
+{
+	let len = len as usize;
+	let buffer = slice::from_raw_parts(buffer as *const u8, len);
+	for i in 0..len
+	{
+		crate::log!("{}", buffer[i] as char);
+	}
+}

src/elsos.rs

@@ -55,13 +55,13 @@ pub extern "C" fn kernel_main(magic: u32, address: u32)
 		logln!("     #+#    #+#             :` .'._.'. `;    Willkumme uf elsOS {}.{}.{}{}", VERSION, PATCHLEVEL, SUBLEVEL, EXTRAVERSION);
 		logln!("    ###   #########         '-`'.___.'`-'   Hello, kernel world !");
 		logln!();
-		tests();
 		tty::prompt();
 		unsafe
 		{
 			arch::interrupts::init();
 			arch::interrupts::enable();
 		}
+		tests();
 		loop
 		{
 			arch::halt();
@@ -72,6 +72,12 @@ pub extern "C" fn kernel_main(magic: u32, address: u32)
 fn tests()
 {
 	// put tests here
+	unsafe
+	{
+		let text = [b'H', b'e', b'l', b'l', b'o', b'\n'];
+		let len = 6;
+		ferramenta::syscall(1, 0, &text as *const _ as u32, len);
+	}
 }
 
 fn init_vga()

src/ferramenta.rs

@@ -1,6 +1,8 @@
-use core::slice;
 use crate::memory;
 
+use core::slice;
+use core::arch::asm;
+
 pub fn shutdown_qemu()
 {
 	crate::arch::port::outw(0x604, 0x2000);
@@ -93,6 +95,18 @@ pub unsafe fn print_memory_bin(ptr: *const u8, n: usize)
 	crate::logln!();
 }
 
+pub unsafe fn syscall(syscall_number: u32, arg1: u32, arg2: u32, arg3: u32) -> u32
+{
+	let ret: u32;
+	asm!("int 0x80",
+			in("eax") syscall_number,
+			in("ebx") arg1,
+			in("ecx") arg2,
+			in("edx") arg3,
+			lateout("eax") ret);
+	ret
+}
+
 #[macro_export]
 macro_rules! get_reg
 {