Remove useless libc, elf and ucontext, add comments to exceptions

improve propagation of errors in raise_exception

Cargo.lock

@@ -7,7 +7,6 @@ name = "burritos"
 version = "0.1.0"
 dependencies = [
  "cc",
- "libc",
 ]
 
 [[package]]
@@ -15,9 +14,3 @@ name = "cc"
 version = "1.0.79"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "50d30906286121d95be3d479533b458f87493b30a4b5f79a607db8f5d11aa91f"
-
-[[package]]
-name = "libc"
-version = "0.2.140"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "99227334921fae1a979cf0bfdfcc6b3e5ce376ef57e16fb6fb3ea2ed6095f80c"

Cargo.toml

@@ -3,9 +3,6 @@ name = "burritos"
 version = "0.1.0"
 edition = "2021"
 
-[dependencies]
-libc = { version = "0.2.139", features = ["extra_traits"] }
-
 [registries.crates-io]
 protocol = "sparse"
 

src/kernel/elf.rs

@@ -1,143 +0,0 @@
-//Declaration des alias
-
-/*
- Def ELF : 
-
- The  header  file  <elf.h>  defines the format of ELF executable binary
-       files.  Amongst these files are normal  executable  files,  relocatable
-       object files, core files and shared libraries.
-
-       An executable file using the ELF file format consists of an ELF header,
-       followed by a program header table or a section header table, or  both.
-       The  ELF  header  is  always  at  offset zero of the file.  The program
-       header table and the section header table's  offset  in  the  file  are
-       defined  in  the  ELF  header.  The two tables describe the rest of the
-       particularities of the file
- */
-
-
-/* Type for a 16-bit quantity.  */
-
-type Elf32_Half = u16;
-
-type Elf64_Half = u16;
-
-/* Types for signed and unsigned 32-bit quantities.  */
-
-type Elf32_Word = u32;
-
-type Elf32_Sword = i32;
-
-type Elf64_Word = u32;
-
-type Elf64_Sword = i32;
-
-/* Types for signed and unsigned 64-bit quantities.  */
-
-type Elf32_Xword = u64;
-
-type Elf32_Sxword = i64;
-
-type Elf64_Xword = u64;
-
-type Elf64_Sxword = i64;
-
-/* Type of addresses.  */
-
-type Elf32_Addr = u32;
-
-type Elf64_Addr = u64;
-
-/* Type of file offsets.  */
-
-type Elf32_Off = u32;
-
-type Elf64_Off = u64;
-
-//role de ce truc ?
-const EI_NIDENT : u8 = 16;
-
-//ELF file header 32 bits
-struct Elf32Ehdr{
-      e_ident : [u8;EI_NIDENT],//16 octects décrivant comment le fichier doit etre parsé
-      //e_ident must starts with magice number : 0x 7f 45 4c 46
-      e_type : Elf32_Half,//type of the file
-      e_machine : Elf32_Half,//type architecture machine
-      e_version : Elf32_Word,//always 1
-      e_entry : Elf32_Addr,//entry point @ for executable
-      e_phoff : Elf32_Off,//Offset of the program header table
-      e_shoff : Elf32_Off,//Offset of the section header table
-      e_flags : Elf32_Word,//des flags ?
-      e_ehsize : Elf32_Half,//size of this (the header), redundant
-      e_phentsize : Elf32_Half,//size per program header
-      e_phnum : Elf32_Half,//number of program header
-      e_shentsize : Elf32_Half,//size per section header
-      e_shnum : Elf32_Half,//number of section header
-      e_shstrndx : Elf32_Half//section header string table index
-}
-
-
-//ELF file header 64 bits
-//les champs ont le meme rôle que dans le header 32 bits
-struct Elf64Ehdr{
-      e_ident : [u8;EI_NIDENT],
-      e_type : Elf64_Half,
-      e_machine : Elf64_Half,
-      e_version : Elf64_Word,
-      e_entry : Elf64_Addr,
-      e_phoff : Elf64_Off,
-      e_shoff : Elf64_Off,
-      e_flags : Elf64_Word,
-      e_ehsize : Elf64_Half,
-      e_phentsize : Elf64_Half,
-      e_phnum : Elf64_Half,
-      e_shentsize : Elf64_Half,
-      e_shnum : Elf64_Half,
-      e_shstrndx : Elf64_Half
-}
-
-
-
-/* e_ident offsets */
-const EI_MAG0 : u32 = 0;
-const EI_MAG1 : u32 = 1;
-const EI_MAG2 : u32 = 2;
-const EI_MAG3 : u32 = 3;
-const EI_CLASS : u32 = 4;  
-const EI_DATA : u32 = 5;  
-const EI_VERSION : u32 = 6;  
-const EI_PAD : u32 = 7;  
-
-/* e_ident[EI_CLASS] */
-const ELFCLASSNONE : u32 = 0;
-const ELFCLASS32 : u32 = 1;
-const ELFCLASS64 : u32 = 2;
-
-/* e_ident[EI_DATA] */
-const ELFDATANONE : u32 = 0;
-const  ELFDATA2LSB : u32 = 1;
-const  ELFDATA2MSB : u32 = 2;
-
-/* e_type */
-const  ET_NONE : u32 = 0;  /* No file type       */
-const  ET_REL : u32 = 1;  /* Relocatable file   */
-const  ET_EXEC : u32 = 2;  /* Executable file    */
-const  ET_DYN : u32 = 3;  /* Shared object file */
-const  ET_CORE : u32 = 4;  /* Core file          */
-const  ET_LOPROC : u32 = 0xff00;  /* Processor-specific */
-const  ET_HIPROC : u32 = 0xffff;  /* Processor-specific */
-
-/* e_machine */
-const  EM_NONE : u32 = 0;  /* No machine     */
-const  EM_M32 : u32 = 1;  /* AT&T WE 32100  */
-const  EM_SPARC : u32 = 2;  /* SPARC          */
-const  EM_386 : u32 = 3; /* Intel 80386    */
-const  EM_68K : u32 = 4;  /* Motorola 68000 */
-const  EM_88K : u32 = 5;  /* Motorola 88000 */
-const  EM_860 : u32 = 7;  /* Intel 80860    */
-const  EM_MIPS : u32 = 8; /* MIPS R3000     */
-const  EM_RISC : u32 = 243; /* RISCV */
-
-/* e_version */
- const EV_NONE : u32 = 0; /* invalid version */
- const EV_CURRENT : u32 = 1; /* current version */

src/kernel/exception.rs

@@ -4,41 +4,109 @@ use crate::simulator::{machine::{ExceptionType, Machine}, error::{MachineOk, Mac
 
 use super::system::System;
 
-
+/// The halt system call. Stops Burritos.
 pub const SC_SHUTDOWN: u8 =	0;
+/// The exit system call
+/// 
+/// Ends the calling thread
 pub const SC_EXIT: u8 =	1;
+/// The exec system call
+/// 
+/// Creates a new process (thread+address space)
 pub const SC_EXEC: u8 =	2;
+/// The join system call
+/// 
+/// Wait for the thread idThread to finish
 pub const SC_JOIN: u8 =	3;
+/// The create system call
+/// 
+/// Create a new file in nachos file system
 pub const SC_CREATE: u8 = 4;
+/// The open system call
+/// 
+/// Opens a file and returns an openfile identifier
 pub const SC_OPEN: u8 =	5;
+/// The read system call
+/// 
+/// Read in a file or the console
 pub const SC_READ: u8 =	6;
+/// The write system call
+/// 
+/// Write in a file or at the console
 pub const SC_WRITE: u8 = 7;
+/// Seek to a given position in an opened file
 pub const SC_SEEK: u8 = 8;
+/// The close system call
+/// 
+/// Close a file
 pub const SC_CLOSE: u8 = 9;
+/// The newThread system call
+///
+///  Create a new thread in the same address space
 pub const SC_NEW_THREAD: u8 = 10;
+/// The Yield System call
+/// 
+/// Relinquish the CPU if any other thread is runnable
 pub const SC_YIELD: u8 = 11;
+/// the PError system call
+/// 
+/// print the last error message
 pub const SC_PERROR: u8 = 12;
+/// carry out P() on the semaphore
 pub const SC_P: u8 = 13;
+/// carry out V() on the semaphore 
 pub const SC_V: u8 = 14;
+/// create a semaphore and add it in g_objects_addrs
 pub const SC_SEM_CREATE: u8 = 15;
+/// destroy the semaphore corresponding to the id
 pub const SC_SEM_DESTROY: u8 = 16;
+/// create a lock and add it to g_object_addrs
 pub const SC_LOCK_CREATE: u8 = 17;
+/// destroy the lock corresponding to the id
 pub const SC_LOCK_DESTROY: u8 = 18;
+/// carry out acquire() on the lock
 pub const SC_LOCK_ACQUIRE: u8 = 19;
+/// carry out release() on the lock 
 pub const SC_LOCK_RELEASE: u8 = 20;
+/// create a condition variable and add it to g_object_addrs
 pub const SC_COND_CREATE: u8 = 21;
+/// destroy the condition variable corresponding to the id
 pub const SC_COND_DESTROY: u8 = 22;
+/// carry out wait() on the condition 
 pub const SC_COND_WAIT: u8 = 23;
+/// carry out signal() on the condition 
 pub const SC_COND_SIGNAL: u8 = 24;
+/// carry out broadcast() on the condition 
 pub const SC_COND_BROADCAST: u8 = 25;
+/// the TtySend system call	
+/// 
+/// Sends some char by the serial line emulated
 pub const SC_TTY_SEND: u8 = 26;
+/// the TtyReceive system call	
+/// 
+/// read some char on the serial line
 pub const SC_TTY_RECEIVE: u8 = 27;
+/// the Mkdir system call
+/// 
+/// make a new directory in the file system 
 pub const SC_MKDIR: u8 = 28;
+/// the Rmdir system call
+/// 
+/// remove a directory from the file system
 pub const SC_RMDIR: u8 = 29;
+/// The Remove system call
+/// 
+/// Remove a file from the file system
 pub const SC_REMOVE: u8 = 30;
+/// The FSList system call
+/// 
+/// Lists all the file and directories in the filesystem
 pub const SC_FSLIST: u8 = 31;
+// The systime system call. Gets the system time
 pub const SC_SYS_TIME: u8 = 32;
+/// Map a file in memory
 pub const SC_MMAP: u8 = 33;
+/// Behaviour undefined and currently unused
 pub const SC_DEBUG: u8 = 34;
 
 pub const CONSOLE_OUTPUT: u8 = 1;
@@ -47,15 +115,15 @@ pub const CONSOLE_OUTPUT: u8 = 1;
 pub fn call(exception: &ExceptionType, machine: &mut Machine, system: &mut System) -> Result<MachineOk, MachineError> {
 
     match exception {
-        ExceptionType::NoException => todo!(),
+        ExceptionType::NoException => Err("No Exception no yet implemented")?,
         ExceptionType::SyscallException => syscall(machine, system),
-        ExceptionType::PagefaultException => todo!(),
+        ExceptionType::PagefaultException => Err("Page Fault Exception not yet implemented")?,
-        ExceptionType::ReadOnlyException => todo!(),
+        ExceptionType::ReadOnlyException => Err("Read Only Exception not yet implemented")?,
-        ExceptionType::BusErrorException => todo!(),
+        ExceptionType::BusErrorException => Err("Bus Error Exception not yet implemented")?,
-        ExceptionType::AddressErrorException => todo!(),
+        ExceptionType::AddressErrorException => Err("AddressErrorException not yet implemented")?,
-        ExceptionType::OverflowException => todo!(),
+        ExceptionType::OverflowException => Err("OverflowException not yet implemented")?,
-        ExceptionType::IllegalInstrException => todo!(),
+        ExceptionType::IllegalInstrException => Err("IllegalInstrException not yet implemented")?,
-        ExceptionType::NumExceptionTypes => todo!(),
+        ExceptionType::NumExceptionTypes => Err("NumExceptionTypes not yet implemented")?,
     }
 }
 
@@ -92,11 +160,10 @@ fn syscall(machine: &mut Machine, system: &mut System) -> Result<MachineOk, Mach
 
             if f as u8 == CONSOLE_OUTPUT {
                 println!("{}", buffer); // todo replace with console driver in the future
-            } else {
-                todo!("SC_WRITE to file is not yet implemented")
-            }
-
                 Ok(MachineOk::Ok)
+            } else {
+                Err("SC_WRITE to file is not yet implemented")?
+            }
         },
         SC_SEEK => todo!(),
         SC_CLOSE => todo!(),

src/kernel/mod.rs

@@ -2,7 +2,6 @@ pub mod process;
 pub mod thread;
 pub mod mgerror;
 pub mod system;
-mod ucontext;
 mod synch;
 mod thread_manager;
 pub mod exception;

src/kernel/ucontext.rs

@@ -1,74 +0,0 @@
-#[cfg(not(target_os = "windows"))]
-use std::mem::MaybeUninit;
-
-/// Safe wrapper for ucontext_t struct of linux-gnu libc
-/// 
-/// setcontext and getcontext are unsafe function, this wrap unsafe libc functions 
-/// 
-/// This struct doesn't work on windows, because this struct is unavailable
-/// 
-/// todo ucontext_t is not thread-safe (doesn't implements Send and Sync trait), and cannot be use in Threads as rust require var in Mutex (see system.rs) to have everything inside to implements thread-safe traits
-#[derive(PartialEq)]
-pub struct UContextT {
-    #[cfg(not(target_os = "windows"))] // struct non disponible sur la libc sur windows
-    pub buf: libc::ucontext_t,
-    pub stack_bottom: Vec<i8>
-}
-
-#[cfg(not(target_os = "windows"))]
-#[allow(unused)] // Temporary as we currently doesn't use this structure (this structure may disapear in a near future)
-impl UContextT {
-
-    pub fn new() -> Self {
-        let mut context = MaybeUninit::<libc::ucontext_t>::uninit();
-        unsafe { libc::getcontext(context.as_mut_ptr()) };
-        Self {
-            buf: unsafe  { context.assume_init() },
-            stack_bottom: Vec::default(),
-        }
-    }
-
-    /// Get user context and store it in variable pointed to by UCP.
-    /// 
-    /// Use `man getcontext` for more informations
-    pub fn get_context(&mut self) -> i32 {
-        unsafe {
-            libc::getcontext(&mut self.buf)
-        }
-    }
-
-    /// Set user context from information of variable pointed to by UCP.
-    /// 
-    /// Use `man setcontext` for more informations
-    pub fn set_context(&mut self) -> i32 {
-        unsafe {
-            libc::setcontext(&self.buf)
-        }
-    }
-
-    pub fn make_context(&mut self, func: extern "C" fn(), args: i32) {
-        unsafe {
-            libc::makecontext(&mut self.buf, func, args)
-        }
-    }
-    
-}
-
-#[cfg(target_os = "windows")]
-#[allow(unused)]
-impl UContextT {
-
-    pub fn new() -> Self {
-        Self {
-            stack_bottom: Vec::default()
-        }
-    }
-
-    pub fn get_context(&mut self) {
-        // no op
-    }
-
-    pub fn set_context(&mut self) {
-        // no op
-    }
-}

src/simulator/machine.rs

@@ -231,14 +231,12 @@ impl Machine {
 		self.set_status(MachineStatus::SystemMode);
 		// Handle the interruption
 		match exception::call(&exception, self, system) {
-			Ok(MachineOk::Shutdown) => {
+			Ok(r) => {
 				self.set_status(MachineStatus::UserMode);
-				return Ok(MachineOk::Shutdown);
+				Ok(r)
+			},
+			Err(e) => Err(format!("Syscall {:?} invalid or not implemented", e))?
 		}
-			_ => Err(format!("Syscall {:?} invalid or not implemented", exception))?
-		} // todo: return error if the syscall code is invalid 
-		self.set_status(MachineStatus::UserMode);
-		Ok(MachineOk::Ok)
 	}
 
 	/// Execute the instructions table of a machine putted in param
@@ -249,7 +247,7 @@ impl Machine {
 	pub fn run(&mut self, system: &mut System) {
 		loop {
 			match self.one_instruction(system) {
-				Ok(MachineOk::Ok) => println!("hello"),
+				Ok(MachineOk::Ok) => {},
 				Ok(MachineOk::Shutdown) => break,
 				Err(e) => panic!("FATAL at pc {} -> {}", self.pc, e)
 			}