add derive procedural macro for pod

src/Cargo.lock

@@ -97,6 +97,15 @@ dependencies = [
  "x86_64",
 ]
 
+[[package]]
+name = "kxos-frame-pod-derive"
+version = "0.1.0"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "kxos-pci"
 version = "0.1.0"
@@ -114,6 +123,7 @@ version = "0.1.0"
 dependencies = [
  "bitflags",
  "kxos-frame",
+ "kxos-frame-pod-derive",
  "kxos-pci",
  "kxos-virtio",
  "lazy_static",

src/Cargo.toml

@@ -17,6 +17,7 @@ members = [
     "kxos-pci",
     "kxos-virtio",
     "kxos-util",
+    "kxos-frame-pod-derive",
 ]
 
 [package.metadata.bootloader]

src/kxos-frame-pod-derive/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "kxos-frame-pod-derive"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[lib]
+proc-macro = true
+
+[dependencies]
+proc-macro2 = "1.0"
+quote = "1.0"
+syn = "1.0.90"

src/kxos-frame-pod-derive/src/lib.rs

@@ -0,0 +1,49 @@
+use proc_macro2::TokenStream;
+use quote::quote;
+use syn::{parse_macro_input, Data, DataStruct, DeriveInput, Fields};
+
+#[proc_macro_derive(Pod)]
+pub fn derive_pod(input_token: proc_macro::TokenStream) -> proc_macro::TokenStream {
+    let input = parse_macro_input!(input_token as DeriveInput);
+    expand_derive_pod(input).into()
+}
+
+fn expand_derive_pod(input: DeriveInput) -> TokenStream {
+    let ident = input.ident;
+    let fields = match input.data {
+        Data::Struct(DataStruct { fields, .. }) => match fields {
+            Fields::Named(fields_named) => fields_named.named,
+            Fields::Unnamed(fields_unnamed) => fields_unnamed.unnamed,
+            Fields::Unit => panic!("derive pod does not work for struct with unit field"),
+        },
+        // Panic on compilation time if one tries to derive pod for enum or union.
+        // It may not be a good idea, but works now.
+        _ => panic!("derive pod only works for struct now."),
+    };
+
+    // deal with generics
+    let (impl_generics, type_generics, where_clause) = input.generics.split_for_impl();
+
+    let pod_where_predicates = fields
+        .into_iter()
+        .map(|field| {
+            let field_ty = field.ty;
+            quote! {
+                #field_ty: ::kxos_frame::Pod
+            }
+        })
+        .collect::<Vec<_>>();
+
+    // if where_clause is none, we should add a `where` word manually.
+    if where_clause.is_none() {
+        quote! {
+            #[automatically_derived]
+            unsafe impl #impl_generics ::kxos_frame::Pod #type_generics for #ident where #(#pod_where_predicates),* {}
+        }
+    } else {
+        quote! {
+            #[automatically_derived]
+            unsafe impl #impl_generics ::kxos_frame::Pod #type_generics for #ident #where_clause, #(#pod_where_predicates),* {}
+        }
+    }
+}

src/kxos-std/Cargo.toml

@@ -7,6 +7,7 @@ edition = "2021"
 
 [dependencies]
 kxos-frame = {path = "../kxos-frame"}
+kxos-frame-pod-derive = {path = "../kxos-frame-pod-derive"}
 kxos-pci = {path="../kxos-pci"}
 kxos-virtio = {path="../kxos-virtio"}
 

src/kxos-std/src/lib.rs

@@ -20,6 +20,8 @@ mod memory;
 mod process;
 pub mod syscall;
 mod util;
+#[macro_use]
+extern crate kxos_frame_pod_derive;
 
 pub fn init() {
     driver::init();

src/kxos-std/src/memory/mod.rs

@@ -33,7 +33,7 @@ pub fn load_elf_to_vm_space<'a>(
 }
 
 /// copy bytes from user space of current process. The bytes len is the len of dest.
-pub fn copy_bytes_from_user(src: Vaddr, dest: &mut [u8]) {
+pub fn read_bytes_from_user(src: Vaddr, dest: &mut [u8]) {
     let current = Process::current();
     let vm_space = current
         .vm_space()
@@ -42,7 +42,7 @@ pub fn copy_bytes_from_user(src: Vaddr, dest: &mut [u8]) {
 }
 
 /// copy val (Plain of Data type) from user space of current process.
-pub fn copy_val_from_user<T: Pod>(src: Vaddr) -> T {
+pub fn read_val_from_user<T: Pod>(src: Vaddr) -> T {
     let current = Process::current();
     let vm_space = current
         .vm_space()
@@ -60,10 +60,10 @@ pub fn write_bytes_to_user(dest: Vaddr, src: &[u8]) {
 }
 
 /// write val (Plain of Data type) to user space of current process.
-pub fn write_val_to_user<T: Pod>(dest: Vaddr, val: T) {
+pub fn write_val_to_user<T: Pod>(dest: Vaddr, val: &T) {
     let current = Process::current();
     let vm_space = current
         .vm_space()
         .expect("[Internal error]Current should have vm space to write val to user");
-    vm_space.write_val(dest, &val).expect("write val failed");
+    vm_space.write_val(dest, val).expect("write val failed");
 }

src/kxos-std/src/syscall/futex.rs

@@ -1,4 +1,4 @@
-use crate::{memory::copy_val_from_user, syscall::SYS_FUTEX};
+use crate::{memory::read_val_from_user, syscall::SYS_FUTEX};
 
 use super::SyscallResult;
 use alloc::{sync::Arc, vec::Vec};
@@ -340,7 +340,7 @@ impl FutexKey {
     pub fn load_val(&self) -> i32 {
         // FIXME: how to implement a atomic load?
         warn!("implement an atomic load");
-        copy_val_from_user(self.0)
+        read_val_from_user(self.0)
     }
 
     pub fn addr(&self) -> Vaddr {

src/kxos-std/src/syscall/readlink.rs

@@ -4,7 +4,7 @@ use alloc::ffi::CString;
 use kxos_frame::{debug, vm::Vaddr};
 
 use crate::{
-    memory::{copy_bytes_from_user, write_bytes_to_user},
+    memory::{read_bytes_from_user, write_bytes_to_user},
     process::Process,
     syscall::SYS_READLINK,
 };
@@ -32,7 +32,7 @@ pub fn do_sys_readlink(filename_ptr: Vaddr, user_buf_ptr: Vaddr, user_buf_len: u
 
     let mut filename_buffer = [0u8; MAX_FILENAME_LEN];
     let current = Process::current();
-    copy_bytes_from_user(filename_ptr, &mut filename_buffer);
+    read_bytes_from_user(filename_ptr, &mut filename_buffer);
     let filename = CStr::from_bytes_until_nul(&filename_buffer).expect("Invalid filename");
     debug!("filename = {:?}", filename);
     if filename == CString::new("/proc/self/exe").unwrap().as_c_str() {

src/kxos-std/src/syscall/uname.rs

@@ -5,10 +5,13 @@ use kxos_frame::{debug, vm::Vaddr};
 use lazy_static::lazy_static;
 
 use crate::{
-    memory::write_bytes_to_user,
+    memory::write_val_to_user,
     syscall::{SyscallResult, SYS_UNAME},
 };
 
+// The values are used to fool glibc. Since glibc will check the version and os name
+// We don't use lazy static to generate a static UTS_NAME is because lazy static will create a new struct, which does not inherent the trait.å
+
 lazy_static! {
     /// used to fool glibc
     static ref SYS_NAME: CString = CString::new("Linux").unwrap();
@@ -31,6 +34,7 @@ lazy_static! {
 
 const UTS_FIELD_LEN: usize = 65;
 
+#[derive(Debug, Clone, Copy, Pod)]
 #[repr(C)]
 struct UtsName {
     sysname: [u8; UTS_FIELD_LEN],
@@ -71,11 +75,6 @@ pub fn do_sys_uname(old_uname_addr: Vaddr) -> usize {
     debug!("uts name size: {}", core::mem::size_of::<UtsName>());
     debug!("uts name align: {}", core::mem::align_of::<UtsName>());
 
-    write_bytes_to_user(old_uname_addr, &UTS_NAME.sysname);
-    write_bytes_to_user(old_uname_addr + UTS_FIELD_LEN, &UTS_NAME.nodename);
-    write_bytes_to_user(old_uname_addr + UTS_FIELD_LEN * 2, &UTS_NAME.release);
-    write_bytes_to_user(old_uname_addr + UTS_FIELD_LEN * 3, &UTS_NAME.version);
-    write_bytes_to_user(old_uname_addr + UTS_FIELD_LEN * 4, &UTS_NAME.machine);
-    write_bytes_to_user(old_uname_addr + UTS_FIELD_LEN * 5, &UTS_NAME.domainname);
+    write_val_to_user(old_uname_addr, &*UTS_NAME);
     0
 }

src/kxos-std/src/syscall/wait4.rs

@@ -17,7 +17,7 @@ pub fn sys_wait4(wait_pid: u64, exit_status_ptr: u64, wait_options: u64) -> Sysc
     let process_filter = ProcessFilter::from_wait_pid(wait_pid as _);
     let (return_pid, exit_code) = wait_child_exit(process_filter, wait_options);
     if return_pid != 0 && exit_status_ptr != 0 {
-        write_val_to_user(exit_status_ptr as _, exit_code);
+        write_val_to_user(exit_status_ptr as _, &exit_code);
     }
 
     SyscallResult::Return(return_pid as _)

src/kxos-std/src/syscall/write.rs

@@ -1,7 +1,7 @@
 use alloc::vec;
 use kxos_frame::{debug, info};
 
-use crate::{memory::copy_bytes_from_user, syscall::SYS_WRITE};
+use crate::{memory::read_bytes_from_user, syscall::SYS_WRITE};
 
 use super::SyscallResult;
 
@@ -14,7 +14,7 @@ pub fn sys_write(fd: u64, user_buf_ptr: u64, user_buf_len: u64) -> SyscallResult
 
     if fd == STDOUT || fd == STDERR {
         let mut buffer = vec![0u8; user_buf_len as usize];
-        copy_bytes_from_user(user_buf_ptr as usize, &mut buffer);
+        read_bytes_from_user(user_buf_ptr as usize, &mut buffer);
         let content = alloc::str::from_utf8(buffer.as_slice()).expect("Invalid content"); // TODO: print content
         if fd == STDOUT {
             info!("Message from user mode: {:?}", content);

src/kxos-std/src/syscall/writev.rs

@@ -2,7 +2,7 @@ use alloc::vec;
 use kxos_frame::{debug, info, vm::Vaddr};
 
 use crate::{
-    memory::{copy_bytes_from_user, copy_val_from_user},
+    memory::{read_bytes_from_user, read_val_from_user},
     syscall::SYS_WRITEV,
 };
 
@@ -10,6 +10,8 @@ use super::SyscallResult;
 
 const IOVEC_MAX: usize = 256;
 
+#[repr(C)]
+#[derive(Debug, Clone, Copy, Pod)]
 pub struct IoVec {
     base: Vaddr,
     len: usize,
@@ -27,12 +29,13 @@ pub fn do_sys_writev(fd: u64, io_vec_addr: Vaddr, io_vec_count: usize) -> usize
     debug!("io_vec_counter = 0x{:x}", io_vec_count);
     let mut write_len = 0;
     for i in 0..io_vec_count {
-        let base = copy_val_from_user::<usize>(io_vec_addr + i * 8);
-        let len = copy_val_from_user::<usize>(io_vec_addr + i * 8 + 8);
+        let io_vec = read_val_from_user::<IoVec>(io_vec_addr + i * 8);
+        let base = io_vec.base;
+        let len = io_vec.len;
         debug!("base = 0x{:x}", base);
         debug!("len = {}", len);
         let mut buffer = vec![0u8; len];
-        copy_bytes_from_user(base, &mut buffer);
+        read_bytes_from_user(base, &mut buffer);
         let content = alloc::str::from_utf8(&buffer).unwrap();
         write_len += len;
         if fd == 1 {