add syscall rt_sigaction and rt_sigreturn

src/kxos-frame/src/sync/wait.rs

@@ -3,7 +3,7 @@ use core::sync::atomic::{AtomicBool, Ordering};
 use alloc::{collections::VecDeque, sync::Arc, vec::Vec};
 use spin::mutex::Mutex;
 
-use crate::{debug, task::Task};
+use crate::task::Task;
 
 /// A wait queue.
 ///
@@ -214,7 +214,7 @@ impl<D: Clone + Eq + PartialEq> Waiter<D> {
     pub fn wait(&self) {
         while !self.is_woken_up.load(Ordering::Relaxed) {
             // yield the execution, to allow other task to contine
-            debug!("Waiter: wait");
+            // debug!("Waiter: wait");
             Task::yield_now();
         }
     }

src/kxos-std/src/process/exception.rs

@@ -8,6 +8,7 @@ pub fn handle_exception(context: &mut CpuContext) {
     let current = current!();
     let pid = current.pid();
     debug!("trap info = {:x?}", trap_info);
+    debug!("cpu context = {:x?}", context);
     let signal = Box::new(FaultSignal::new(&trap_info));
     current.sig_queues().lock().enqueue(signal);
 }

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

@@ -14,6 +14,7 @@ use self::signal::sig_disposition::SigDispositions;
 use self::signal::sig_mask::SigMask;
 use self::signal::sig_queues::SigQueues;
 use self::signal::signals::kernel::KernelSignal;
+use self::signal::SigContext;
 use self::status::ProcessStatus;
 use self::task::create_user_task_from_elf;
 
@@ -64,6 +65,8 @@ pub struct Process {
     sig_queues: Mutex<SigQueues>,
     /// Process-level sigmask
     sig_mask: Mutex<SigMask>,
+    /// Signal handler Context
+    sig_context: Mutex<Option<SigContext>>,
 }
 
 impl Process {
@@ -116,6 +119,7 @@ impl Process {
             sig_dispositions: Mutex::new(sig_dispositions),
             sig_queues: Mutex::new(sig_queues),
             sig_mask: Mutex::new(sig_mask),
+            sig_context: Mutex::new(None),
         }
     }
 
@@ -222,6 +226,10 @@ impl Process {
         &self.process_group
     }
 
+    pub fn sig_context(&self) -> &Mutex<Option<SigContext>> {
+        &self.sig_context
+    }
+
     /// add a child process
     pub fn add_child(&self, child: Arc<Process>) {
         debug!("process: {}, add child: {} ", self.pid(), child.pid());

src/kxos-std/src/process/process_filter.rs

@@ -21,7 +21,7 @@ impl ProcessFilter {
     }
 
     // used for wait4 and kill
-    pub fn from_id(wait_pid: isize) -> Self {
+    pub fn from_id(wait_pid: i32) -> Self {
         // https://man7.org/linux/man-pages/man2/waitpid.2.html
         // https://man7.org/linux/man-pages/man2/kill.2.html
         if wait_pid < -1 {

src/kxos-std/src/process/signal/c_types.rs

@@ -0,0 +1,13 @@
+#![allow(non_camel_case_types)]
+use crate::prelude::*;
+
+pub type sigset_t = u64;
+
+#[derive(Debug, Clone, Copy, Pod)]
+#[repr(C)]
+pub struct sigaction_t {
+    pub handler_ptr: Vaddr,
+    pub flags: u32,
+    pub restorer_ptr: Vaddr,
+    pub mask: sigset_t,
+}

src/kxos-std/src/process/signal/mod.rs

@@ -1,3 +1,4 @@
+pub mod c_types;
 pub mod constants;
 pub mod sig_action;
 pub mod sig_disposition;
@@ -6,15 +7,19 @@ pub mod sig_num;
 pub mod sig_queues;
 pub mod signals;
 
-use kxos_frame::task::Task;
+use kxos_frame::{cpu::CpuContext, task::Task};
 
+use self::sig_mask::SigMask;
+use self::sig_num::SigNum;
+use crate::memory::{write_bytes_to_user, write_val_to_user};
+use crate::process::signal::sig_action::SigActionFlags;
 use crate::{
     prelude::*,
     process::signal::sig_action::{SigAction, SigDefaultAction},
 };
 
 /// Handle pending signal for current process
-pub fn handle_pending_signal() {
+pub fn handle_pending_signal(context: &mut CpuContext) {
     let current = current!();
     let pid = current.pid();
     let process_name = current.filename().unwrap();
@@ -25,12 +30,24 @@ pub fn handle_pending_signal() {
         let sig_num = signal.num();
         debug!("sig_num = {:?}, sig_name = {}", sig_num, sig_num.sig_name());
         let sig_action = current.sig_dispositions().lock().get(sig_num);
-        debug!("sig action: {:?}", sig_action);
+        debug!("sig action: {:x?}", sig_action);
         match sig_action {
             SigAction::Ign => {
                 debug!("Ignore signal {:?}", sig_num);
             }
-            SigAction::User { .. } => todo!(),
+            SigAction::User {
+                handler_addr,
+                flags,
+                restorer_addr,
+                mask,
+            } => handle_user_signal_handler(
+                sig_num,
+                handler_addr,
+                flags,
+                restorer_addr,
+                mask,
+                context,
+            ),
             SigAction::Dfl => {
                 let sig_default_action = SigDefaultAction::from_signum(sig_num);
                 debug!("sig_default_action: {:?}", sig_default_action);
@@ -70,3 +87,85 @@ pub fn handle_pending_signal() {
         }
     }
 }
+
+pub fn handle_user_signal_handler(
+    sig_num: SigNum,
+    handler_addr: Vaddr,
+    flags: SigActionFlags,
+    restorer_addr: Vaddr,
+    mask: SigMask,
+    context: &mut CpuContext,
+) {
+    debug!("sig_num = {:?}", sig_num);
+    debug!("handler_addr = 0x{:x}", handler_addr);
+    debug!("flags = {:?}", flags);
+    debug!("restorer_addr = 0x{:x}", restorer_addr);
+    // FIXME: How to respect flags
+    if flags.intersects(!(SigActionFlags::SA_RESTART | SigActionFlags::SA_RESTORER)) {
+        panic!("Unsupported Signal flags");
+    }
+    let current = current!();
+    // block signals in sigmask when running signal handler
+    current.sig_mask().lock().block(mask.as_u64());
+    // store context in current process
+    let sig_context = SigContext::new(context.clone(), mask);
+    *(current.sig_context().lock()) = Some(sig_context);
+    // set up signal stack in user stack
+    let mut user_rsp = context.gp_regs.rsp;
+    // avoid corrupt user stack, we minus 128 first.
+    user_rsp = user_rsp - 128;
+    // Copy the trampoline code.
+    if flags.contains(SigActionFlags::SA_RESTORER) {
+        // If contains SA_RESTORER flag, trampoline code is provided by libc in restorer_addr.
+        // We just store restorer_addr on user stack to allow user code just to trampoline code.
+        user_rsp = write_u64_to_user_stack(user_rsp, restorer_addr as u64);
+    } else {
+        // Otherwise we create
+        const TRAMPOLINE: &[u8] = &[
+            0xb8, 0x0f, 0x00, 0x00, 0x00, // mov eax, 15(syscall number of rt_sigreturn)
+            0x0f, 0x05, // syscall (call rt_sigreturn)
+            0x90, // nop (for alignment)
+        ];
+        user_rsp = user_rsp - TRAMPOLINE.len() as u64;
+        let trampoline_rip = user_rsp;
+        write_bytes_to_user(user_rsp as Vaddr, TRAMPOLINE);
+        user_rsp = write_u64_to_user_stack(user_rsp, trampoline_rip);
+    }
+    context.gp_regs.rip = handler_addr as _;
+    context.gp_regs.rsp = user_rsp;
+    // parameters of signal handler
+    context.gp_regs.rdi = sig_num.as_u8() as u64; // signal number
+    context.gp_regs.rsi = 0; // siginfo_t* siginfo
+    context.gp_regs.rdx = 0; // void* ctx
+}
+
+fn write_u64_to_user_stack(rsp: u64, value: u64) -> u64 {
+    let rsp = rsp - 8;
+    write_val_to_user(rsp as Vaddr, &value);
+    rsp
+}
+
+/// Used to store process context before running signal handler.
+/// In rt_sigreturn, this context is used to restore process context.
+#[derive(Debug, Clone, Copy)]
+pub struct SigContext {
+    cpu_context: CpuContext,
+    sig_mask: SigMask,
+}
+
+impl SigContext {
+    pub const fn new(cpu_context: CpuContext, sig_mask: SigMask) -> SigContext {
+        Self {
+            cpu_context,
+            sig_mask,
+        }
+    }
+
+    pub fn cpu_context(&self) -> &CpuContext {
+        &self.cpu_context
+    }
+
+    pub fn sig_mask(&self) -> &SigMask {
+        &self.sig_mask
+    }
+}

src/kxos-std/src/process/signal/sig_action.rs

@@ -1,4 +1,5 @@
-use super::{constants::*, sig_mask::SigMask, sig_num::SigNum};
+use super::{c_types::sigaction_t, constants::*, sig_mask::SigMask, sig_num::SigNum};
+use crate::prelude::*;
 use bitflags::bitflags;
 use kxos_frame::warn;
 
@@ -21,6 +22,58 @@ impl Default for SigAction {
     }
 }
 
+impl TryFrom<sigaction_t> for SigAction {
+    type Error = Error;
+
+    fn try_from(input: sigaction_t) -> Result<Self> {
+        let action = match input.handler_ptr {
+            SIG_DFL => SigAction::Dfl,
+            SIG_IGN => SigAction::Ign,
+            _ => {
+                let flags = SigActionFlags::from_bits_truncate(input.flags);
+                let mask = SigMask::from(input.mask);
+                SigAction::User {
+                    handler_addr: input.handler_ptr,
+                    flags,
+                    restorer_addr: input.restorer_ptr,
+                    mask,
+                }
+            }
+        };
+        Ok(action)
+    }
+}
+
+impl SigAction {
+    pub fn to_c(&self) -> sigaction_t {
+        match self {
+            SigAction::Dfl => sigaction_t {
+                handler_ptr: SIG_DFL,
+                flags: 0,
+                restorer_ptr: 0,
+                mask: 0,
+            },
+            SigAction::Ign => sigaction_t {
+                handler_ptr: SIG_IGN,
+                flags: 0,
+                restorer_ptr: 0,
+                mask: 0,
+            },
+            SigAction::User {
+                handler_addr,
+                flags,
+                restorer_addr,
+                mask,
+            } => sigaction_t {
+                handler_ptr: *handler_addr,
+                flags: flags.to_u32(),
+                restorer_ptr: *restorer_addr,
+                mask: mask.as_u64(),
+            },
+        }
+    }
+}
+
 bitflags! {
     pub struct SigActionFlags: u32 {
         const SA_NOCLDSTOP  = 1;
@@ -35,10 +88,11 @@ bitflags! {
 }
 
 impl TryFrom<u32> for SigActionFlags {
-    type Error = &'static str;
+    type Error = Error;
 
-    fn try_from(bits: u32) -> Result<Self, Self::Error> {
-        let flags = SigActionFlags::from_bits(bits).ok_or_else(|| "invalid sigaction flags")?;
+    fn try_from(bits: u32) -> Result<Self> {
+        let flags = SigActionFlags::from_bits(bits)
+            .ok_or_else(|| Error::with_message(Errno::EINVAL, "invalid sig action flag"))?;
         if flags.contains(SigActionFlags::SA_RESTART) {
             warn!("SA_RESTART is not supported");
         }

src/kxos-std/src/process/task.rs

@@ -57,7 +57,7 @@ pub fn create_new_task(userspace: Arc<UserSpace>, parent: Weak<Process>) -> Arc<
             if current.status().lock().is_zombie() {
                 break;
             }
-            handle_pending_signal();
+            handle_pending_signal(context);
             if current.status().lock().is_zombie() {
                 debug!("exit due to signal");
                 break;
@@ -66,7 +66,7 @@ pub fn create_new_task(userspace: Arc<UserSpace>, parent: Weak<Process>) -> Arc<
             while current.status().lock().is_suspend() {
                 Process::yield_now();
                 debug!("{} is suspended.", current.pid());
-                handle_pending_signal();
+                handle_pending_signal(context);
             }
         }
         debug!("exit user loop");

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

@@ -1,12 +1,12 @@
-use super::constants::*;
+use super::{constants::*, SyscallReturn};
 use crate::{memory::read_bytes_from_user, prelude::*, syscall::SYS_ACCESS};
 
-pub fn sys_access(filename_ptr: Vaddr, file_mode: u64) -> Result<isize> {
+pub fn sys_access(filename_ptr: Vaddr, file_mode: u64) -> Result<SyscallReturn> {
     debug!("[syscall][id={}][SYS_ACCESS]", SYS_ACCESS);
     let mut filename_buffer = vec![0u8; MAX_FILENAME_LEN];
     read_bytes_from_user(filename_ptr, &mut filename_buffer);
     let filename = CString::from(CStr::from_bytes_until_nul(&filename_buffer).unwrap());
     debug!("filename: {:?}", filename);
     warn!("access currenly does not check and just return success");
-    Ok(0)
+    Ok(SyscallReturn::Return(0))
 }

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

@@ -3,6 +3,8 @@ use kxos_frame::cpu::CpuContext;
 use crate::prelude::*;
 use crate::syscall::SYS_ARCH_PRCTL;
 
+use super::SyscallReturn;
+
 #[allow(non_camel_case_types)]
 #[derive(Debug)]
 pub enum ArchPrctlCode {
@@ -26,19 +28,12 @@ impl TryFrom<u64> for ArchPrctlCode {
     }
 }
 
-pub fn sys_arch_prctl(code: u64, addr: u64, context: &mut CpuContext) -> Result<isize> {
+pub fn sys_arch_prctl(code: u64, addr: u64, context: &mut CpuContext) -> Result<SyscallReturn> {
     debug!("[syscall][id={}][SYS_ARCH_PRCTL]", SYS_ARCH_PRCTL);
     let arch_prctl_code = ArchPrctlCode::try_from(code)?;
     debug!("arch_prctl_code: {:?}", arch_prctl_code);
     let res = do_arch_prctl(arch_prctl_code, addr, context).unwrap();
-    Ok(res as _)
-    // match arch_prctl_code {
-    //     Err(_) => SyscallResult::Return(-1),
-    //     Ok(code) => {
-    //         let res = do_arch_prctl(code, addr, context).unwrap();
-    //         SyscallResult::Return(res as _)
-    //     }
-    // }
+    Ok(SyscallReturn::Return(res as _))
 }
 
 pub fn do_arch_prctl(code: ArchPrctlCode, addr: u64, context: &mut CpuContext) -> Result<u64> {

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

@@ -1,9 +1,10 @@
 use crate::prelude::*;
 
+use crate::syscall::SyscallReturn;
 use crate::{process::Process, syscall::SYS_BRK};
 
 /// expand the user heap to new heap end, returns the new heap end if expansion succeeds.
-pub fn sys_brk(heap_end: u64) -> Result<isize> {
+pub fn sys_brk(heap_end: u64) -> Result<SyscallReturn> {
     debug!("[syscall][id={}][SYS_BRK]", SYS_BRK);
     let current = Process::current();
     let new_heap_end = if heap_end == 0 {
@@ -20,5 +21,5 @@ pub fn sys_brk(heap_end: u64) -> Result<isize> {
         .expect("brk should work on process with user space");
     let new_heap_end = user_heap.brk(new_heap_end, vm_space);
 
-    Ok(new_heap_end as _)
+    Ok(SyscallReturn::Return(new_heap_end as _))
 }

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

@@ -3,6 +3,8 @@ use kxos_frame::cpu::CpuContext;
 use crate::process::clone::{clone_child, CloneArgs, CloneFlags};
 use crate::{prelude::*, syscall::SYS_CLONE};
 
+use super::SyscallReturn;
+
 // The order of arguments for clone differs in different architecture.
 // This order we use here is the order for x86_64. See https://man7.org/linux/man-pages/man2/clone.2.html.
 pub fn sys_clone(
@@ -12,7 +14,7 @@ pub fn sys_clone(
     child_tidptr: Vaddr,
     tls: usize,
     parent_context: CpuContext,
-) -> Result<isize> {
+) -> Result<SyscallReturn> {
     debug!("[syscall][id={}][SYS_CLONE]", SYS_CLONE);
     debug!("flags = {}", clone_flags);
     let clone_flags = CloneFlags::from(clone_flags);
@@ -28,5 +30,5 @@ pub fn sys_clone(
     debug!("*********schedule child process, pid = {}**********", pid);
     child_process.send_to_scheduler();
     debug!("*********return to parent process, pid = {}*********", pid);
-    Ok(child_pid as _)
+    Ok(SyscallReturn::Return(child_pid as _))
 }

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

@@ -1,6 +1,6 @@
 use kxos_frame::cpu::CpuContext;
 
-use super::constants::*;
+use super::{constants::*, SyscallReturn};
 use crate::process::elf::load_elf_to_vm_space;
 use crate::{memory::read_bytes_from_user, prelude::*, process::Process, syscall::SYS_EXECVE};
 
@@ -9,7 +9,7 @@ pub fn sys_execve(
     argv_ptr_ptr: Vaddr,
     envp_ptr_ptr: Vaddr,
     context: &mut CpuContext,
-) -> Result<isize> {
+) -> Result<SyscallReturn> {
     debug!("[syscall][id={}][SYS_EXECVE]", SYS_EXECVE);
     let mut filename_buffer = vec![0u8; MAX_FILENAME_LEN];
     read_bytes_from_user(filename_ptr, &mut filename_buffer);
@@ -40,11 +40,12 @@ pub fn sys_execve(
     let defalut_content = CpuContext::default();
     context.gp_regs = defalut_content.gp_regs;
     context.fs_base = defalut_content.fs_base;
+    context.fp_regs = defalut_content.fp_regs;
     // set new entry point
     context.gp_regs.rip = elf_load_info.entry_point();
     debug!("entry_point: 0x{:x}", elf_load_info.entry_point());
     // set new user stack top
     context.gp_regs.rsp = elf_load_info.user_stack_top();
     debug!("user stack top: 0x{:x}", elf_load_info.user_stack_top());
-    Ok(0)
+    Ok(SyscallReturn::NoReturn)
 }

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

@@ -1,9 +1,9 @@
 use crate::prelude::*;
 
-use crate::syscall::SYS_EXIT;
+use crate::syscall::{SyscallReturn, SYS_EXIT};
 
-pub fn sys_exit(exit_code: i32) -> Result<isize> {
+pub fn sys_exit(exit_code: i32) -> Result<SyscallReturn> {
     debug!("[syscall][id={}][SYS_EXIT]", SYS_EXIT);
     current!().exit(exit_code);
-    Ok(0)
+    Ok(SyscallReturn::Return(0))
 }

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

@@ -1,9 +1,9 @@
 use crate::prelude::*;
 
-use crate::syscall::SYS_EXIT_GROUP;
+use crate::syscall::{SyscallReturn, SYS_EXIT_GROUP};
 
-pub fn sys_exit_group(exit_code: u64) -> Result<isize> {
+pub fn sys_exit_group(exit_code: u64) -> Result<SyscallReturn> {
     debug!("[syscall][id={}][SYS_EXIT_GROUP]", SYS_EXIT_GROUP);
     current!().exit(exit_code as _);
-    Ok(0)
+    Ok(SyscallReturn::Return(0))
 }

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

@@ -6,10 +6,12 @@ use kxos_frame::cpu::CpuContext;
 
 use crate::{process::Process, syscall::SYS_FORK};
 
-pub fn sys_fork(parent_context: CpuContext) -> Result<isize> {
+use super::SyscallReturn;
+
+pub fn sys_fork(parent_context: CpuContext) -> Result<SyscallReturn> {
     debug!("[syscall][id={}][SYS_FORK]", SYS_FORK);
     let child_process = fork(parent_context);
-    Ok(child_process.pid() as _)
+    Ok(SyscallReturn::Return(child_process.pid() as _))
 }
 
 /// Fork a child process

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

@@ -3,9 +3,9 @@ use kxos_frame::vm::VmIo;
 use crate::fs::stat::Stat;
 use crate::prelude::*;
 
-use crate::syscall::SYS_FSTAT;
+use crate::syscall::{SyscallReturn, SYS_FSTAT};
 
-pub fn sys_fstat(fd: u64, stat_buf_ptr: Vaddr) -> Result<isize> {
+pub fn sys_fstat(fd: u64, stat_buf_ptr: Vaddr) -> Result<SyscallReturn> {
     debug!("[syscall][id={}][SYS_FSTAT]", SYS_FSTAT);
     debug!("fd = {}", fd);
     debug!("stat_buf_addr = 0x{:x}", stat_buf_ptr);
@@ -19,8 +19,8 @@ pub fn sys_fstat(fd: u64, stat_buf_ptr: Vaddr) -> Result<isize> {
         vm_space
             .write_val(stat_buf_ptr, &stat)
             .expect("Write value failed");
-        return Ok(0);
+        return Ok(SyscallReturn::Return(0));
     }
     warn!("TODO: fstat only returns fake result now.");
-    Ok(0)
+    Ok(SyscallReturn::Return(0))
 }

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

@@ -1,3 +1,4 @@
+use crate::syscall::SyscallReturn;
 use crate::{memory::read_val_from_user, syscall::SYS_FUTEX};
 
 use crate::prelude::*;
@@ -17,7 +18,7 @@ pub fn sys_futex(
     utime_addr: u64,
     futex_new_addr: u64,
     bitset: u64,
-) -> Result<isize> {
+) -> Result<SyscallReturn> {
     debug!("[syscall][id={}][SYS_FUTEX]", SYS_FUTEX);
     // FIXME: we current ignore futex flags
     let (futex_op, futex_flags) = futex_op_and_flags_from_u32(futex_op as _).unwrap();
@@ -69,7 +70,7 @@ pub fn sys_futex(
     }
     .unwrap();
 
-    Ok(res as _)
+    Ok(SyscallReturn::Return(res as _))
 }
 
 /// do futex wait

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

@@ -0,0 +1,9 @@
+use crate::{prelude::*, syscall::SYS_GETEGID};
+
+use super::SyscallReturn;
+
+pub fn sys_getegid() -> Result<SyscallReturn> {
+    debug!("[syscall][id={}][SYS_GETEGID]", SYS_GETEGID);
+    warn!("TODO: getegid only return a fake egid now");
+    Ok(SyscallReturn::Return(0))
+}

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

@@ -0,0 +1,9 @@
+use crate::{prelude::*, syscall::SYS_GETEUID};
+
+use super::SyscallReturn;
+
+pub fn sys_geteuid() -> Result<SyscallReturn> {
+    debug!("[syscall][id={}][SYS_GETEUID]", SYS_GETEUID);
+    warn!("TODO: geteuid only return a fake euid now");
+    Ok(SyscallReturn::Return(0))
+}

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

@@ -0,0 +1,9 @@
+use crate::{prelude::*, syscall::SYS_GETGID};
+
+use super::SyscallReturn;
+
+pub fn sys_getgid() -> Result<SyscallReturn> {
+    debug!("[syscall][id={}][SYS_GETGID]", SYS_GETGID);
+    warn!("TODO: getgid only return a fake gid now");
+    Ok(SyscallReturn::Return(0))
+}

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

@@ -2,9 +2,11 @@ use crate::prelude::*;
 
 use crate::{process::Process, syscall::SYS_GETPID};
 
-pub fn sys_getpid() -> Result<isize> {
+use super::SyscallReturn;
+
+pub fn sys_getpid() -> Result<SyscallReturn> {
     debug!("[syscall][id={}][SYS_GETPID]", SYS_GETPID);
     let pid = Process::current().pid();
     info!("[sys_getpid]: pid = {}", pid);
-    Ok(pid as _)
+    Ok(SyscallReturn::Return(pid as _))
 }

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

@@ -2,9 +2,11 @@ use crate::prelude::*;
 
 use crate::{process::Process, syscall::SYS_GETTID};
 
-pub fn sys_gettid() -> Result<isize> {
+use super::SyscallReturn;
+
+pub fn sys_gettid() -> Result<SyscallReturn> {
     debug!("[syscall][id={}][SYS_GETTID]", SYS_GETTID);
     // For single-thread process, tid is equal to pid
     let tid = Process::current().pid();
-    Ok(tid as _)
+    Ok(SyscallReturn::Return(tid as _))
 }

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

@@ -0,0 +1,9 @@
+use crate::{prelude::*, syscall::SYS_GETUID};
+
+use super::SyscallReturn;
+
+pub fn sys_getuid() -> Result<SyscallReturn> {
+    debug!("[syscall][id={}][SYS_GETUID]", SYS_GETUID);
+    warn!("TODO: getuid only return a fake uid now");
+    Ok(SyscallReturn::Return(0))
+}

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

@@ -7,12 +7,14 @@ use crate::{
     syscall::SYS_KILL,
 };
 
-pub fn sys_kill(process_filter: u64, sig_num: u64) -> Result<isize> {
+use super::SyscallReturn;
+
+pub fn sys_kill(process_filter: u64, sig_num: u64) -> Result<SyscallReturn> {
     debug!("[syscall][id={}][SYS_KILL]", SYS_KILL);
     let process_filter = ProcessFilter::from_id(process_filter as _);
     let sig_num = SigNum::try_from(sig_num as u8).unwrap();
     do_sys_kill(process_filter, sig_num)?;
-    Ok(0)
+    Ok(SyscallReturn::Return(0))
 }
 
 pub fn do_sys_kill(process_filter: ProcessFilter, sig_num: SigNum) -> Result<()> {

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

@@ -6,6 +6,8 @@ use kxos_frame::vm::VmPerm;
 
 use crate::{process::Process, syscall::SYS_MMAP};
 
+use super::SyscallReturn;
+
 pub fn sys_mmap(
     addr: u64,
     len: u64,
@@ -13,7 +15,7 @@ pub fn sys_mmap(
     flags: u64,
     fd: u64,
     offset: u64,
-) -> Result<isize> {
+) -> Result<SyscallReturn> {
     debug!("[syscall][id={}][SYS_MMAP]", SYS_MMAP);
     let perms = VmPerm::try_from(perms).unwrap();
     let flags = MMapFlags::try_from(flags).unwrap();
@@ -25,7 +27,7 @@ pub fn sys_mmap(
         fd as usize,
         offset as usize,
     );
-    Ok(res as _)
+    Ok(SyscallReturn::Return(res as _))
 }
 
 pub fn do_sys_mmap(

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

@@ -1,33 +1,38 @@
 //! Read the Cpu context content then dispatch syscall to corrsponding handler
 //! The each sub module contains functions that handle real syscall logic.
-
 use crate::prelude::*;
-use crate::syscall::clone::sys_clone;
-use crate::syscall::kill::sys_kill;
-use crate::syscall::rt_sigprocmask::sys_rt_sigprocmask;
-use alloc::borrow::ToOwned;
-use kxos_frame::cpu::CpuContext;
-
 use crate::syscall::access::sys_access;
 use crate::syscall::arch_prctl::sys_arch_prctl;
 use crate::syscall::brk::sys_brk;
+use crate::syscall::clone::sys_clone;
 use crate::syscall::execve::sys_execve;
 use crate::syscall::exit::sys_exit;
 use crate::syscall::exit_group::sys_exit_group;
 use crate::syscall::fork::sys_fork;
 use crate::syscall::fstat::sys_fstat;
 use crate::syscall::futex::sys_futex;
+use crate::syscall::getegid::sys_getegid;
+use crate::syscall::geteuid::sys_geteuid;
+use crate::syscall::getgid::sys_getgid;
 use crate::syscall::getpid::sys_getpid;
 use crate::syscall::gettid::sys_gettid;
+use crate::syscall::getuid::sys_getuid;
+use crate::syscall::kill::sys_kill;
 use crate::syscall::mmap::sys_mmap;
 use crate::syscall::mprotect::sys_mprotect;
 use crate::syscall::readlink::sys_readlink;
+use crate::syscall::rt_sigaction::sys_rt_sigaction;
+use crate::syscall::rt_sigprocmask::sys_rt_sigprocmask;
+use crate::syscall::rt_sigreturn::sys_rt_sigreturn;
+use crate::syscall::sched_yield::sys_sched_yield;
 use crate::syscall::tgkill::sys_tgkill;
 use crate::syscall::uname::sys_uname;
 use crate::syscall::wait4::sys_wait4;
 use crate::syscall::waitid::sys_waitid;
 use crate::syscall::write::sys_write;
 use crate::syscall::writev::sys_writev;
+use crate::{define_syscall_nums, syscall_handler};
+use kxos_frame::cpu::CpuContext;
 
 mod access;
 mod arch_prctl;
@@ -40,13 +45,19 @@ mod exit_group;
 mod fork;
 mod fstat;
 mod futex;
+mod getegid;
+mod geteuid;
+mod getgid;
 mod getpid;
 mod gettid;
+mod getuid;
 mod kill;
 mod mmap;
 mod mprotect;
 mod readlink;
+mod rt_sigaction;
 mod rt_sigprocmask;
+mod rt_sigreturn;
 mod sched_yield;
 mod tgkill;
 mod uname;
@@ -55,41 +66,58 @@ mod waitid;
 mod write;
 mod writev;
 
-const SYS_WRITE: u64 = 1;
-const SYS_FSTAT: u64 = 5;
-const SYS_MMAP: u64 = 9;
-const SYS_MPROTECT: u64 = 10;
-const SYS_BRK: u64 = 12;
-const SYS_RT_SIGACTION: u64 = 13;
-const SYS_RT_SIGPROCMASK: u64 = 14;
-const SYS_WRITEV: u64 = 20;
-const SYS_ACCESS: u64 = 21;
-const SYS_SCHED_YIELD: u64 = 24;
-const SYS_GETPID: u64 = 39;
-const SYS_CLONE: u64 = 56;
-const SYS_FORK: u64 = 57;
-const SYS_EXECVE: u64 = 59;
-const SYS_EXIT: u64 = 60;
-const SYS_WAIT4: u64 = 61;
-const SYS_KILL: u64 = 62;
-const SYS_UNAME: u64 = 63;
-const SYS_READLINK: u64 = 89;
-const SYS_GETUID: u64 = 102;
-const SYS_GETGID: u64 = 104;
-const SYS_GETEUID: u64 = 107;
-const SYS_GETEGID: u64 = 108;
-const SYS_ARCH_PRCTL: u64 = 158;
-const SYS_GETTID: u64 = 186;
-const SYS_FUTEX: u64 = 202;
-const SYS_EXIT_GROUP: u64 = 231;
-const SYS_TGKILL: u64 = 234;
-const SYS_WAITID: u64 = 247;
+define_syscall_nums!(
+    SYS_WRITE = 1,
+    SYS_FSTAT = 5,
+    SYS_MMAP = 9,
+    SYS_MPROTECT = 10,
+    SYS_BRK = 12,
+    SYS_RT_SIGACTION = 13,
+    SYS_RT_SIGPROCMASK = 14,
+    SYS_RT_SIGRETRUN = 15,
+    SYS_WRITEV = 20,
+    SYS_ACCESS = 21,
+    SYS_SCHED_YIELD = 24,
+    SYS_IOCTL = 29,
+    SYS_GETPID = 39,
+    SYS_CLONE = 56,
+    SYS_FORK = 57,
+    SYS_EXECVE = 59,
+    SYS_EXIT = 60,
+    SYS_WAIT4 = 61,
+    SYS_KILL = 62,
+    SYS_UNAME = 63,
+    SYS_GETPPID = 64,
+    SYS_FCNTL = 72,
+    SYS_READLINK = 89,
+    SYS_GETUID = 102,
+    SYS_GETGID = 104,
+    SYS_GETEUID = 107,
+    SYS_GETEGID = 108,
+    SYS_GETPGRP = 111,
+    SYS_PRCTL = 157,
+    SYS_ARCH_PRCTL = 158,
+    SYS_GETCWD = 183,
+    SYS_GETTID = 186,
+    SYS_FUTEX = 202,
+    SYS_EXIT_GROUP = 231,
+    SYS_TGKILL = 234,
+    SYS_WAITID = 247
+);
 
 pub struct SyscallArgument {
     syscall_number: u64,
     args: [u64; 6],
 }
 
+/// Syscall return
+pub enum SyscallReturn {
+    /// return isize, this value will be used to set rax
+    Return(isize),
+    /// does not need to set rax
+    NoReturn,
+}
+
 impl SyscallArgument {
     fn new_from_context(context: &CpuContext) -> Self {
         let syscall_number = context.gp_regs.rax;
@@ -114,92 +142,91 @@ pub fn handle_syscall(context: &mut CpuContext) {
 
     match syscall_return {
         Ok(return_value) => {
-            context.gp_regs.rax = return_value as u64;
+            if let SyscallReturn::Return(return_value) = return_value {
+                context.gp_regs.rax = return_value as u64;
+            }
         }
         Err(err) => {
             let errno = err.error() as i32;
             context.gp_regs.rax = (-errno) as u64
         }
     }
-    // if let Syscal(return_value) = syscall_return {
-    //     // FIXME: set return value?
-    //     context.gp_regs.rax = return_value as u64;
-    // }
 }
 
 pub fn syscall_dispatch(
     syscall_number: u64,
     args: [u64; 6],
     context: &mut CpuContext,
-) -> Result<isize> {
+) -> Result<SyscallReturn> {
     match syscall_number {
-        SYS_WRITE => sys_write(args[0], args[1], args[2]),
-        SYS_FSTAT => sys_fstat(args[0], args[1] as _),
-        SYS_MMAP => sys_mmap(args[0], args[1], args[2], args[3], args[4], args[5]),
-        SYS_MPROTECT => sys_mprotect(args[0], args[1], args[2]),
-        SYS_BRK => sys_brk(args[0]),
-        SYS_RT_SIGACTION => sys_rt_sigaction(),
-        SYS_RT_SIGPROCMASK => {
-            sys_rt_sigprocmask(args[0] as _, args[1] as _, args[2] as _, args[3] as _)
-        }
-        SYS_WRITEV => sys_writev(args[0], args[1], args[2]),
-        SYS_ACCESS => sys_access(args[0] as _, args[1]),
-        SYS_GETPID => sys_getpid(),
-        SYS_CLONE => sys_clone(
-            args[0],
-            args[1] as _,
-            args[2] as _,
-            args[3] as _,
-            args[4] as _,
-            context.to_owned(),
-        ),
-        SYS_FORK => sys_fork(context.to_owned()),
-        SYS_EXECVE => sys_execve(args[0] as _, args[1] as _, args[2] as _, context),
-        SYS_EXIT => sys_exit(args[0] as _),
-        SYS_WAIT4 => sys_wait4(args[0], args[1], args[2]),
-        SYS_KILL => sys_kill(args[0], args[1]),
-        SYS_UNAME => sys_uname(args[0]),
-        SYS_READLINK => sys_readlink(args[0], args[1], args[2]),
-        SYS_GETUID => sys_getuid(),
-        SYS_GETGID => sys_getgid(),
-        SYS_GETEUID => sys_geteuid(),
-        SYS_GETEGID => sys_getegid(),
-        SYS_ARCH_PRCTL => sys_arch_prctl(args[0], args[1], context),
-        SYS_GETTID => sys_gettid(),
-        SYS_FUTEX => sys_futex(args[0], args[1], args[2], args[3], args[4], args[5]),
-        SYS_EXIT_GROUP => sys_exit_group(args[0]),
-        SYS_TGKILL => sys_tgkill(args[0], args[1], args[2]),
-        SYS_WAITID => sys_waitid(args[0], args[1], args[2], args[3], args[4]),
+        SYS_WRITE => syscall_handler!(3, sys_write, args),
+        SYS_FSTAT => syscall_handler!(2, sys_fstat, args),
+        SYS_MMAP => syscall_handler!(6, sys_mmap, args),
+        SYS_MPROTECT => syscall_handler!(3, sys_mprotect, args),
+        SYS_BRK => syscall_handler!(1, sys_brk, args),
+        SYS_RT_SIGACTION => syscall_handler!(4, sys_rt_sigaction, args),
+        SYS_RT_SIGPROCMASK => syscall_handler!(4, sys_rt_sigprocmask, args),
+        SYS_RT_SIGRETRUN => syscall_handler!(0, sys_rt_sigreturn, context),
+        SYS_WRITEV => syscall_handler!(3, sys_writev, args),
+        SYS_ACCESS => syscall_handler!(2, sys_access, args),
+        SYS_SCHED_YIELD => syscall_handler!(0, sys_sched_yield),
+        SYS_IOCTL => todo!(),
+        SYS_GETPID => syscall_handler!(0, sys_getpid),
+        SYS_CLONE => syscall_handler!(5, sys_clone, args, context.clone()),
+        SYS_FORK => syscall_handler!(0, sys_fork, context.clone()),
+        SYS_EXECVE => syscall_handler!(3, sys_execve, args, context),
+        SYS_EXIT => syscall_handler!(1, sys_exit, args),
+        SYS_WAIT4 => syscall_handler!(3, sys_wait4, args),
+        SYS_KILL => syscall_handler!(2, sys_kill, args),
+        SYS_UNAME => syscall_handler!(1, sys_uname, args),
+        SYS_GETPPID => todo!(),
+        SYS_FCNTL => todo!(),
+        SYS_READLINK => syscall_handler!(3, sys_readlink, args),
+        SYS_GETUID => syscall_handler!(0, sys_getuid),
+        SYS_GETGID => syscall_handler!(0, sys_getgid),
+        SYS_GETEUID => syscall_handler!(0, sys_geteuid),
+        SYS_GETEGID => syscall_handler!(0, sys_getegid),
+        SYS_GETPGRP => todo!(),
+        SYS_PRCTL => todo!(),
+        SYS_ARCH_PRCTL => syscall_handler!(2, sys_arch_prctl, args, context),
+        SYS_GETCWD => todo!(),
+        SYS_GETTID => syscall_handler!(0, sys_gettid),
+        SYS_FUTEX => syscall_handler!(6, sys_futex, args),
+        SYS_EXIT_GROUP => syscall_handler!(1, sys_exit_group, args),
+        SYS_TGKILL => syscall_handler!(3, sys_tgkill, args),
+        SYS_WAITID => syscall_handler!(5, sys_waitid, args),
         _ => panic!("Unsupported syscall number: {}", syscall_number),
     }
 }
 
-pub fn sys_rt_sigaction() -> Result<isize> {
-    debug!("[syscall][id={}][SYS_RT_SIGACTION]", SYS_RT_SIGACTION);
-    warn!("TODO: rt_sigaction only return a fake result");
-    Ok(0)
+/// This macro is used to define syscall handler.
+/// The first param is ths number of parameters,
+/// The second param is the function name of syscall handler,
+/// The third is optional, means the args(if parameter number > 0),
+/// The third is optional, means if cpu context is required.
+#[macro_export]
+macro_rules! syscall_handler {
+    (0, $fn_name: ident) => { $fn_name() };
+    (0, $fn_name: ident, $context: expr) => { $fn_name($context) };
+    (1, $fn_name: ident, $args: ident) => { $fn_name($args[0] as _) };
+    (1, $fn_name: ident, $args: ident, $context: expr) => { $fn_name($args[0] as _, $context) };
+    (2, $fn_name: ident, $args: ident) => { $fn_name($args[0] as _, $args[1] as _)};
+    (2, $fn_name: ident, $args: ident, $context: expr) => { $fn_name($args[0] as _, $args[1] as _, $context)};
+    (3, $fn_name: ident, $args: ident) => { $fn_name($args[0] as _, $args[1] as _, $args[2] as _)};
+    (3, $fn_name: ident, $args: ident, $context: expr) => { $fn_name($args[0] as _, $args[1] as _, $args[2] as _, $context)};
+    (4, $fn_name: ident, $args: ident) => { $fn_name($args[0] as _, $args[1] as _, $args[2] as _, $args[3] as _)};
+    (4, $fn_name: ident, $args: ident, $context: expr) => { $fn_name($args[0] as _, $args[1] as _, $args[2] as _, $args[3] as _), $context};
+    (5, $fn_name: ident, $args: ident) => { $fn_name($args[0] as _, $args[1] as _, $args[2] as _, $args[3] as _, $args[4] as _)};
+    (5, $fn_name: ident, $args: ident, $context: expr) => { $fn_name($args[0] as _, $args[1] as _, $args[2] as _, $args[3] as _, $args[4] as _, $context)};
+    (6, $fn_name: ident, $args: ident) => { $fn_name($args[0] as _, $args[1] as _, $args[2] as _, $args[3] as _, $args[4] as _, $args[5] as _)};
+    (6, $fn_name: ident, $args: ident, $context: expr) => { $fn_name($args[0] as _, $args[1] as _, $args[2] as _, $args[3] as _, $args[4] as _, $args[5] as _, $context)};
 }
 
-pub fn sys_getuid() -> Result<isize> {
-    debug!("[syscall][id={}][SYS_GETUID]", SYS_GETUID);
-    warn!("TODO: getuid only return a fake uid now");
-    Ok(0)
-}
-
-pub fn sys_getgid() -> Result<isize> {
-    debug!("[syscall][id={}][SYS_GETGID]", SYS_GETGID);
-    warn!("TODO: getgid only return a fake gid now");
-    Ok(0)
-}
-
-pub fn sys_geteuid() -> Result<isize> {
-    debug!("[syscall][id={}][SYS_GETEUID]", SYS_GETEUID);
-    warn!("TODO: geteuid only return a fake euid now");
-    Ok(0)
-}
-
-pub fn sys_getegid() -> Result<isize> {
-    debug!("[syscall][id={}][SYS_GETEGID]", SYS_GETEGID);
-    warn!("TODO: getegid only return a fake egid now");
-    Ok(0)
+#[macro_export]
+macro_rules! define_syscall_nums {
+    ( $( $name: ident = $num: expr ),+ ) => {
+        $(
+            const $name: u64  = $num;
+        )*
+    }
 }

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

@@ -4,11 +4,13 @@ use crate::prelude::*;
 
 use crate::syscall::SYS_MPROTECT;
 
-pub fn sys_mprotect(vaddr: u64, len: u64, perms: u64) -> Result<isize> {
+use super::SyscallReturn;
+
+pub fn sys_mprotect(vaddr: u64, len: u64, perms: u64) -> Result<SyscallReturn> {
     debug!("[syscall][id={}][SYS_MPROTECT]", SYS_MPROTECT);
     let perms = VmPerm::try_from(perms).unwrap();
     do_sys_mprotect(vaddr as Vaddr, len as usize, perms);
-    Ok(0)
+    Ok(SyscallReturn::Return(0))
 }
 
 pub fn do_sys_mprotect(addr: Vaddr, len: usize, perms: VmPerm) -> isize {

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

@@ -6,16 +6,22 @@ use crate::{
     syscall::SYS_READLINK,
 };
 
+use super::SyscallReturn;
+
 const MAX_FILENAME_LEN: usize = 128;
 
-pub fn sys_readlink(filename_ptr: u64, user_buf_ptr: u64, user_buf_len: u64) -> Result<isize> {
+pub fn sys_readlink(
+    filename_ptr: u64,
+    user_buf_ptr: u64,
+    user_buf_len: u64,
+) -> Result<SyscallReturn> {
     debug!("[syscall][id={}][SYS_READLINK]", SYS_READLINK);
     let res = do_sys_readlink(
         filename_ptr as Vaddr,
         user_buf_ptr as Vaddr,
         user_buf_len as usize,
     );
-    Ok(res as _)
+    Ok(SyscallReturn::Return(res as _))
 }
 
 /// do sys readlink

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

@@ -0,0 +1,36 @@
+use crate::{
+    memory::{read_val_from_user, write_val_to_user},
+    prelude::*,
+    process::signal::{c_types::sigaction_t, sig_action::SigAction, sig_num::SigNum},
+    syscall::SYS_RT_SIGACTION,
+};
+
+use super::SyscallReturn;
+
+pub fn sys_rt_sigaction(
+    sig_num: u8,
+    sig_action_ptr: Vaddr,
+    old_sig_action_ptr: Vaddr,
+    sigset_size: u64,
+) -> Result<SyscallReturn> {
+    debug!("[syscall][id={}][SYS_RT_SIGACTION]", SYS_RT_SIGACTION);
+    let sig_num = SigNum::try_from(sig_num)?;
+    debug!("sig_num = {}", sig_num.sig_name());
+    debug!("sig_action_ptr = 0x{:x}", sig_action_ptr);
+    debug!("old_sig_action_ptr = 0x{:x}", old_sig_action_ptr);
+    debug!("sigset_size = {}", sigset_size);
+    let sig_action_c = read_val_from_user::<sigaction_t>(sig_action_ptr);
+    debug!("sig_action_c = {:?}", sig_action_c);
+    let sig_action = SigAction::try_from(sig_action_c).unwrap();
+    debug!("sig_action = {:x?}", sig_action);
+
+    let current = current!();
+    let mut sig_dispositions = current.sig_dispositions().lock();
+    let old_action = sig_dispositions.get(sig_num);
+    debug!("old_action = {:x?}", old_action);
+    let old_action_c = old_action.to_c();
+    debug!("old_action_c = {:x?}", old_action_c);
+    sig_dispositions.set(sig_num, sig_action);
+    write_val_to_user(old_sig_action_ptr, &old_action_c);
+    Ok(SyscallReturn::Return(0))
+}

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

@@ -1,13 +1,16 @@
 use kxos_frame::vm::VmIo;
 
-use crate::{prelude::*, syscall::SYS_RT_SIGPROCMASK};
+use crate::{
+    prelude::*,
+    syscall::{SyscallReturn, SYS_RT_SIGPROCMASK},
+};
 
 pub fn sys_rt_sigprocmask(
     how: u32,
     set_ptr: Vaddr,
     oldset_ptr: Vaddr,
     sigset_size: usize,
-) -> Result<isize> {
+) -> Result<SyscallReturn> {
     debug!("[syscall][id={}][SYS_RT_SIGPROCMASK]", SYS_RT_SIGPROCMASK);
     let mask_op = MaskOp::try_from(how).unwrap();
     debug!("mask op = {:?}", mask_op);
@@ -18,7 +21,7 @@ pub fn sys_rt_sigprocmask(
         warn!("sigset size is not equal to 8");
     }
     do_rt_sigprocmask(mask_op, set_ptr, oldset_ptr, sigset_size).unwrap();
-    Ok(0)
+    Ok(SyscallReturn::Return(0))
 }
 
 fn do_rt_sigprocmask(

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

@@ -0,0 +1,14 @@
+use crate::prelude::*;
+use kxos_frame::cpu::CpuContext;
+
+use super::SyscallReturn;
+
+pub fn sys_rt_sigreturn(context: &mut CpuContext) -> Result<SyscallReturn> {
+    let current = current!();
+    let sig_context = current.sig_context().lock().as_ref().unwrap().clone();
+    *context = *sig_context.cpu_context();
+    // unblock sig mask
+    let sig_mask = sig_context.sig_mask();
+    current.sig_mask().lock().unblock(sig_mask.as_u64());
+    Ok(SyscallReturn::NoReturn)
+}

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

@@ -2,8 +2,10 @@ use crate::prelude::*;
 
 use crate::{process::Process, syscall::SYS_SCHED_YIELD};
 
-pub fn sys_sched_yield() -> Result<isize> {
+use super::SyscallReturn;
+
+pub fn sys_sched_yield() -> Result<SyscallReturn> {
     debug!("[syscall][id={}][SYS_SCHED_YIELD]", SYS_SCHED_YIELD);
     Process::yield_now();
-    Ok(0)
+    Ok(SyscallReturn::Return(0))
 }

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

@@ -2,10 +2,12 @@ use crate::prelude::*;
 
 use crate::syscall::SYS_TGKILL;
 
-pub fn sys_tgkill(tgid: u64, pid: u64, signal: u64) -> Result<isize> {
+use super::SyscallReturn;
+
+pub fn sys_tgkill(tgid: u64, pid: u64, signal: u64) -> Result<SyscallReturn> {
     debug!("[syscall][id={}][SYS_TGKILL]", SYS_TGKILL);
     debug!("tgid = {}", tgid);
     debug!("pid = {}", pid);
     warn!("TODO: tgkill do nothing now");
-    Ok(0)
+    Ok(SyscallReturn::Return(0))
 }

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

@@ -2,6 +2,8 @@ use crate::prelude::*;
 
 use crate::{memory::write_val_to_user, syscall::SYS_UNAME};
 
+use super::SyscallReturn;
+
 // We don't use the real name and version of our os here. Instead, we pick up fake values witch is the same as the ones of linux.
 // The values are used to fool glibc since glibc will check the version and os name.
 lazy_static! {
@@ -56,10 +58,10 @@ fn copy_cstring_to_u8_slice(src: &CStr, dst: &mut [u8]) {
     dst[..len].copy_from_slice(&src[..len]);
 }
 
-pub fn sys_uname(old_uname_addr: u64) -> Result<isize> {
+pub fn sys_uname(old_uname_addr: u64) -> Result<SyscallReturn> {
     debug!("[syscall][id={}][SYS_UNAME]", SYS_UNAME);
     do_sys_uname(old_uname_addr as Vaddr);
-    Ok(0)
+    Ok(SyscallReturn::Return(0))
 }
 
 pub fn do_sys_uname(old_uname_addr: Vaddr) -> usize {

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

@@ -7,10 +7,12 @@ use crate::{
 use crate::prelude::*;
 use crate::process::wait::WaitOptions;
 
-pub fn sys_wait4(wait_pid: u64, exit_status_ptr: u64, wait_options: u64) -> Result<isize> {
+use super::SyscallReturn;
+
+pub fn sys_wait4(wait_pid: u64, exit_status_ptr: u64, wait_options: u64) -> Result<SyscallReturn> {
     debug!("[syscall][id={}][SYS_WAIT4]", SYS_WAIT4);
     let wait_options = WaitOptions::from_bits(wait_options as u32).expect("Unknown wait options");
-    debug!("pid = {}", wait_pid as isize);
+    debug!("pid = {}", wait_pid as i32);
     debug!("exit_status_ptr = {}", exit_status_ptr);
     debug!("wait_options: {:?}", wait_options);
     let process_filter = ProcessFilter::from_id(wait_pid as _);
@@ -18,6 +20,5 @@ pub fn sys_wait4(wait_pid: u64, exit_status_ptr: u64, wait_options: u64) -> Resu
     if return_pid != 0 && exit_status_ptr != 0 {
         write_val_to_user(exit_status_ptr as _, &exit_code);
     }
-
-    Ok(return_pid as _)
+    Ok(SyscallReturn::Return(return_pid as _))
 }

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

@@ -3,16 +3,18 @@ use crate::process::{process_filter::ProcessFilter, wait::wait_child_exit};
 
 use crate::process::wait::WaitOptions;
 
+use super::SyscallReturn;
+
 pub fn sys_waitid(
     which: u64,
     upid: u64,
     infoq_addr: u64,
     options: u64,
     rusage_addr: u64,
-) -> Result<isize> {
+) -> Result<SyscallReturn> {
     // FIXME: what does infoq and rusage use for?
     let process_filter = ProcessFilter::from_which_and_id(which, upid);
     let wait_options = WaitOptions::from_bits(options as u32).expect("Unknown wait options");
     let (exit_code, pid) = wait_child_exit(process_filter, wait_options);
-    Ok(pid as _)
+    Ok(SyscallReturn::Return(pid as _))
 }

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

@@ -2,10 +2,12 @@ use crate::prelude::*;
 
 use crate::{memory::read_bytes_from_user, syscall::SYS_WRITE};
 
+use super::SyscallReturn;
+
 const STDOUT: u64 = 1;
 const STDERR: u64 = 2;
 
-pub fn sys_write(fd: u64, user_buf_ptr: u64, user_buf_len: u64) -> Result<isize> {
+pub fn sys_write(fd: u64, user_buf_ptr: u64, user_buf_len: u64) -> Result<SyscallReturn> {
     // only suppprt STDOUT now.
     debug!("[syscall][id={}][SYS_WRITE]", SYS_WRITE);
 
@@ -18,8 +20,7 @@ pub fn sys_write(fd: u64, user_buf_ptr: u64, user_buf_len: u64) -> Result<isize>
         } else {
             info!("Error message from user mode: {:?}", content);
         }
-
-        Ok(user_buf_len as _)
+        Ok(SyscallReturn::Return(user_buf_len as _))
     } else {
         panic!("Unsupported fd number {}", fd);
     }

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

@@ -5,6 +5,8 @@ use crate::{
     syscall::SYS_WRITEV,
 };
 
+use super::SyscallReturn;
+
 const IOVEC_MAX: usize = 256;
 
 #[repr(C)]
@@ -14,10 +16,10 @@ pub struct IoVec {
     len: usize,
 }
 
-pub fn sys_writev(fd: u64, io_vec_ptr: u64, io_vec_count: u64) -> Result<isize> {
+pub fn sys_writev(fd: u64, io_vec_ptr: u64, io_vec_count: u64) -> Result<SyscallReturn> {
     debug!("[syscall][id={}][SYS_WRITEV]", SYS_WRITEV);
     let res = do_sys_writev(fd, io_vec_ptr as Vaddr, io_vec_count as usize);
-    Ok(res as _)
+    Ok(SyscallReturn::Return(res as _))
 }
 
 pub fn do_sys_writev(fd: u64, io_vec_ptr: Vaddr, io_vec_count: usize) -> usize {

src/kxos-user/execve/execve

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:f98928f25e8223fd76d5d19db68e83913b48ea8b3cf6ae8d3120971e7271c93b
+oid sha256:afc9465a8ae782da4e049d2b660a27b678394e683814c29a9601bc135126a0e5
 size 871952

src/kxos-user/execve/execve.c

@@ -5,9 +5,10 @@ int main() {
     char* argv[] = { NULL };
     char* envp[] = { NULL };
     printf("Execve a new file ./hello:\n");
-    // flust the stdout content to ensure the content print to console
+    // flush the stdout content to ensure the content print to console
     fflush(stdout);
     execve("./hello", argv, envp);
     printf("Should not print\n");
+    fflush(stdout);
     return 0;
 }

src/kxos-user/fork_c/fork

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:4f3b6fe8b52f200c469170223ea0cb2d06dbab6a5eb757e007eb0a751c5e1e81
+oid sha256:ca7a77a72da160f11670a04a16b623944295b9059399da45f57668f121b00d11
 size 877152

src/kxos-user/fork_c/fork.c

@@ -5,9 +5,9 @@ int main() {
     printf("before fork\n");
     fflush(stdout);
     if(fork() == 0) {
-        printf("after fork: Hello from parent\n");
+        printf("after fork: Hello from child\n");
     } else {
-        printf("after fork: Hello from child\n");   
+        printf("after fork: Hello from parent\n");   
     }
     fflush(stdout);
     return 0;

src/kxos-user/signal_c/sig_action

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:08b21d340c8d144c1bfb86097e46ceda6d690041269cf56fee5bd8918e8253fa
+oid sha256:1938c6e8abd70c400780dd8aa089d768a8662d54bac2a658936790d5537e868c
 size 877544

src/kxos-user/signal_c/sig_action.c

@@ -7,7 +7,7 @@
 int sigchld = 0;
 
 void proc_exit() {
-    sigchld = 999;
+    sigchld = sigchld + 1;
 }
 
 int main() {