add os[1-8]-ref for os refereces, add guide, add README

os8-ref/src/syscall/fs.rs

@@ -0,0 +1,114 @@
+//! File and filesystem-related syscalls
+
+use crate::fs::make_pipe;
+use crate::fs::open_file;
+use crate::fs::OpenFlags;
+use crate::fs::Stat;
+use crate::mm::translated_byte_buffer;
+use crate::mm::translated_refmut;
+use crate::mm::translated_str;
+use crate::mm::UserBuffer;
+use crate::task::current_process;
+use crate::task::current_user_token;
+use alloc::sync::Arc;
+
+pub fn sys_write(fd: usize, buf: *const u8, len: usize) -> isize {
+    let token = current_user_token();
+    let process = current_process();
+    let inner = process.inner_exclusive_access();
+    if fd >= inner.fd_table.len() {
+        return -1;
+    }
+    if let Some(file) = &inner.fd_table[fd] {
+        let file = file.clone();
+        // release current process TCB manually to avoid multi-borrow
+        drop(inner);
+        file.write(UserBuffer::new(translated_byte_buffer(token, buf, len))) as isize
+    } else {
+        -1
+    }
+}
+
+pub fn sys_read(fd: usize, buf: *const u8, len: usize) -> isize {
+    let token = current_user_token();
+    let process = current_process();
+    let inner = process.inner_exclusive_access();
+    if fd >= inner.fd_table.len() {
+        return -1;
+    }
+    if let Some(file) = &inner.fd_table[fd] {
+        let file = file.clone();
+        // release current process TCB manually to avoid multi-borrow
+        drop(inner);
+        file.read(UserBuffer::new(translated_byte_buffer(token, buf, len))) as isize
+    } else {
+        -1
+    }
+}
+
+pub fn sys_open(path: *const u8, flags: u32) -> isize {
+    let process = current_process();
+    let token = current_user_token();
+    let path = translated_str(token, path);
+    if let Some(inode) = open_file(path.as_str(), OpenFlags::from_bits(flags).unwrap()) {
+        let mut inner = process.inner_exclusive_access();
+        let fd = inner.alloc_fd();
+        inner.fd_table[fd] = Some(inode);
+        fd as isize
+    } else {
+        -1
+    }
+}
+
+pub fn sys_close(fd: usize) -> isize {
+    let process = current_process();
+    let mut inner = process.inner_exclusive_access();
+    if fd >= inner.fd_table.len() {
+        return -1;
+    }
+    if inner.fd_table[fd].is_none() {
+        return -1;
+    }
+    inner.fd_table[fd].take();
+    0
+}
+
+pub fn sys_pipe(pipe: *mut usize) -> isize {
+    let process = current_process();
+    let token = current_user_token();
+    let mut inner = process.inner_exclusive_access();
+    let (pipe_read, pipe_write) = make_pipe();
+    let read_fd = inner.alloc_fd();
+    inner.fd_table[read_fd] = Some(pipe_read);
+    let write_fd = inner.alloc_fd();
+    inner.fd_table[write_fd] = Some(pipe_write);
+    *translated_refmut(token, pipe) = read_fd;
+    *translated_refmut(token, unsafe { pipe.add(1) }) = write_fd;
+    0
+}
+
+pub fn sys_dup(fd: usize) -> isize {
+    let process = current_process();
+    let mut inner = process.inner_exclusive_access();
+    if fd >= inner.fd_table.len() {
+        return -1;
+    }
+    if inner.fd_table[fd].is_none() {
+        return -1;
+    }
+    let new_fd = inner.alloc_fd();
+    inner.fd_table[new_fd] = Some(Arc::clone(inner.fd_table[fd].as_ref().unwrap()));
+    new_fd as isize
+}
+
+pub fn sys_fstat(_fd: usize, _st: *mut Stat) -> isize {
+    -1
+}
+
+pub fn sys_linkat(_old_name: *const u8, _new_name: *const u8) -> isize {
+    -1
+}
+
+pub fn sys_unlinkat(_name: *const u8) -> isize {
+    -1
+}

os8-ref/src/syscall/mod.rs

@@ -0,0 +1,100 @@
+//! Implementation of syscalls
+//!
+//! The single entry point to all system calls, [`syscall()`], is called
+//! whenever userspace wishes to perform a system call using the `ecall`
+//! instruction. In this case, the processor raises an 'Environment call from
+//! U-mode' exception, which is handled as one of the cases in
+//! [`crate::trap::trap_handler`].
+//!
+//! For clarity, each single syscall is implemented as its own function, named
+//! `sys_` then the name of the syscall. You can find functions like this in
+//! submodules, and you should also implement syscalls this way.
+
+const SYSCALL_DUP: usize = 24;
+const SYSCALL_UNLINKAT: usize = 35;
+const SYSCALL_LINKAT: usize = 37;
+const SYSCALL_OPEN: usize = 56;
+const SYSCALL_CLOSE: usize = 57;
+const SYSCALL_PIPE: usize = 59;
+const SYSCALL_READ: usize = 63;
+const SYSCALL_WRITE: usize = 64;
+const SYSCALL_FSTAT: usize = 80;
+const SYSCALL_EXIT: usize = 93;
+const SYSCALL_SLEEP: usize = 101;
+const SYSCALL_YIELD: usize = 124;
+const SYSCALL_GET_TIME: usize = 169;
+const SYSCALL_GETPID: usize = 172;
+const SYSCALL_GETTID: usize = 178;
+const SYSCALL_FORK: usize = 220;
+const SYSCALL_EXEC: usize = 221;
+const SYSCALL_WAITPID: usize = 260;
+const SYSCALL_SPAWN: usize = 400;
+const SYSCALL_MUNMAP: usize = 215;
+const SYSCALL_MMAP: usize = 222;
+const SYSCALL_SET_PRIORITY: usize = 140;
+const SYSCALL_TASK_INFO: usize = 410;
+const SYSCALL_THREAD_CREATE: usize = 460;
+const SYSCALL_WAITTID: usize = 462;
+const SYSCALL_MUTEX_CREATE: usize = 463;
+const SYSCALL_MUTEX_LOCK: usize = 464;
+const SYSCALL_MUTEX_UNLOCK: usize = 466;
+const SYSCALL_SEMAPHORE_CREATE: usize = 467;
+const SYSCALL_SEMAPHORE_UP: usize = 468;
+const SYSCALL_ENABLE_DEADLOCK_DETECT: usize = 469;
+const SYSCALL_SEMAPHORE_DOWN: usize = 470;
+const SYSCALL_CONDVAR_CREATE: usize = 471;
+const SYSCALL_CONDVAR_SIGNAL: usize = 472;
+const SYSCALL_CONDVAR_WAIT: usize = 473;
+
+mod fs;
+pub mod process;
+mod sync;
+mod thread;
+
+use crate::fs::Stat;
+use fs::*;
+use process::*;
+use sync::*;
+use thread::*;
+
+/// handle syscall exception with `syscall_id` and other arguments
+pub fn syscall(syscall_id: usize, args: [usize; 4]) -> isize {
+    match syscall_id {
+        SYSCALL_DUP => sys_dup(args[0]),
+        SYSCALL_LINKAT => sys_linkat(args[1] as *const u8, args[3] as *const u8),
+        SYSCALL_UNLINKAT => sys_unlinkat(args[1] as *const u8),
+        SYSCALL_OPEN => sys_open(args[1] as *const u8, args[2] as u32),
+        SYSCALL_CLOSE => sys_close(args[0]),
+        SYSCALL_PIPE => sys_pipe(args[0] as *mut usize),
+        SYSCALL_READ => sys_read(args[0], args[1] as *const u8, args[2]),
+        SYSCALL_WRITE => sys_write(args[0], args[1] as *const u8, args[2]),
+        SYSCALL_FSTAT => sys_fstat(args[0], args[1] as *mut Stat),
+        SYSCALL_EXIT => sys_exit(args[0] as i32),
+        SYSCALL_SLEEP => sys_sleep(args[0]),
+        SYSCALL_YIELD => sys_yield(),
+        SYSCALL_GETPID => sys_getpid(),
+        SYSCALL_GETTID => sys_gettid(),
+        SYSCALL_FORK => sys_fork(),
+        SYSCALL_EXEC => sys_exec(args[0] as *const u8, args[1] as *const usize),
+        SYSCALL_WAITPID => sys_waitpid(args[0] as isize, args[1] as *mut i32),
+        SYSCALL_GET_TIME => sys_get_time(args[0] as *mut TimeVal, args[1]),
+        SYSCALL_MMAP => sys_mmap(args[0], args[1], args[2]),
+        SYSCALL_MUNMAP => sys_munmap(args[0], args[1]),
+        SYSCALL_SET_PRIORITY => sys_set_priority(args[0] as isize),
+        SYSCALL_TASK_INFO => sys_task_info(args[0] as *mut TaskInfo),
+        SYSCALL_SPAWN => sys_spawn(args[0] as *const u8),
+        SYSCALL_THREAD_CREATE => sys_thread_create(args[0], args[1]),
+        SYSCALL_WAITTID => sys_waittid(args[0]) as isize,
+        SYSCALL_MUTEX_CREATE => sys_mutex_create(args[0] == 1),
+        SYSCALL_MUTEX_LOCK => sys_mutex_lock(args[0]),
+        SYSCALL_MUTEX_UNLOCK => sys_mutex_unlock(args[0]),
+        SYSCALL_SEMAPHORE_CREATE => sys_semaphore_create(args[0]),
+        SYSCALL_SEMAPHORE_UP => sys_semaphore_up(args[0]),
+        SYSCALL_ENABLE_DEADLOCK_DETECT => sys_enable_deadlock_detect(args[0]),
+        SYSCALL_SEMAPHORE_DOWN => sys_semaphore_down(args[0]),
+        SYSCALL_CONDVAR_CREATE => sys_condvar_create(args[0]),
+        SYSCALL_CONDVAR_SIGNAL => sys_condvar_signal(args[0]),
+        SYSCALL_CONDVAR_WAIT => sys_condvar_wait(args[0], args[1]),
+        _ => panic!("Unsupported syscall_id: {}", syscall_id),
+    }
+}

os8-ref/src/syscall/process.rs

@@ -0,0 +1,158 @@
+//! Process management syscalls
+
+use crate::config::MAX_SYSCALL_NUM;
+use crate::fs::{open_file, OpenFlags};
+use crate::mm::{translated_ref, translated_refmut, translated_str, PageTable, VirtAddr};
+use crate::task::{
+    current_process, current_task, current_user_token, exit_current_and_run_next,
+    suspend_current_and_run_next, TaskStatus,
+};
+use crate::timer::get_time_us;
+use alloc::string::String;
+use alloc::sync::Arc;
+use alloc::vec::Vec;
+
+#[repr(C)]
+#[derive(Debug)]
+pub struct TimeVal {
+    pub sec: usize,
+    pub usec: usize,
+}
+
+#[derive(Clone, Copy)]
+pub struct TaskInfo {
+    pub status: TaskStatus,
+    pub syscall_times: [u32; MAX_SYSCALL_NUM],
+    pub time: usize,
+}
+
+pub fn sys_exit(exit_code: i32) -> ! {
+    // debug!("[kernel] Application exited with code {}", exit_code);
+    exit_current_and_run_next(exit_code);
+    panic!("Unreachable in sys_exit!");
+}
+
+/// current task gives up resources for other tasks
+pub fn sys_yield() -> isize {
+    suspend_current_and_run_next();
+    0
+}
+
+pub fn sys_getpid() -> isize {
+    current_task().unwrap().process.upgrade().unwrap().getpid() as isize
+}
+
+/// Syscall Fork which returns 0 for child process and child_pid for parent process
+pub fn sys_fork() -> isize {
+    let current_process = current_process();
+    let new_process = current_process.fork();
+    let new_pid = new_process.getpid();
+    // modify trap context of new_task, because it returns immediately after switching
+    let new_process_inner = new_process.inner_exclusive_access();
+    let task = new_process_inner.tasks[0].as_ref().unwrap();
+    let trap_cx = task.inner_exclusive_access().get_trap_cx();
+    // we do not have to move to next instruction since we have done it before
+    // for child process, fork returns 0
+    trap_cx.x[10] = 0;
+    new_pid as isize
+}
+
+/// Syscall Exec which accepts the elf path
+pub fn sys_exec(path: *const u8, mut args: *const usize) -> isize {
+    let token = current_user_token();
+    let path = translated_str(token, path);
+    let mut args_vec: Vec<String> = Vec::new();
+    loop {
+        let arg_str_ptr = *translated_ref(token, args);
+        if arg_str_ptr == 0 {
+            break;
+        }
+        args_vec.push(translated_str(token, arg_str_ptr as *const u8));
+        unsafe {
+            args = args.add(1);
+        }
+    }
+    if let Some(app_inode) = open_file(path.as_str(), OpenFlags::RDONLY) {
+        let all_data = app_inode.read_all();
+        let process = current_process();
+        let argc = args_vec.len();
+        process.exec(all_data.as_slice(), args_vec);
+        argc as isize
+    } else {
+        -1
+    }
+}
+
+/// If there is not a child process whose pid is same as given, return -1.
+/// Else if there is a child process but it is still running, return -2.
+pub fn sys_waitpid(pid: isize, exit_code_ptr: *mut i32) -> isize {
+    let process = current_process();
+    // find a child process
+
+    // ---- access current TCB exclusively
+    let mut inner = process.inner_exclusive_access();
+    if !inner
+        .children
+        .iter()
+        .any(|p| pid == -1 || pid as usize == p.getpid())
+    {
+        return -1;
+        // ---- release current PCB
+    }
+    let pair = inner.children.iter().enumerate().find(|(_, p)| {
+        // ++++ temporarily access child PCB lock exclusively
+        p.inner_exclusive_access().is_zombie && (pid == -1 || pid as usize == p.getpid())
+        // ++++ release child PCB
+    });
+    if let Some((idx, _)) = pair {
+        let child = inner.children.remove(idx);
+        // confirm that child will be deallocated after removing from children list
+        assert_eq!(Arc::strong_count(&child), 1);
+        let found_pid = child.getpid();
+        // ++++ temporarily access child TCB exclusively
+        let exit_code = child.inner_exclusive_access().exit_code;
+        // ++++ release child PCB
+        *translated_refmut(inner.memory_set.token(), exit_code_ptr) = exit_code;
+        found_pid as isize
+    } else {
+        -2
+    }
+    // ---- release current PCB lock automatically
+}
+
+pub fn sys_get_time(_ts: *mut TimeVal, _tz: usize) -> isize {
+    let _us = get_time_us();
+    // unsafe {
+    //     *ts = TimeVal {
+    //         sec: us / 1_000_000,
+    //         usec: us % 1_000_000,
+    //     };
+    // }
+    *translated_refmut(current_user_token(), _ts) = TimeVal {
+        sec: _us / 1_000_000,
+        usec: _us % 1_000_000,
+    };
+    0
+}
+
+pub fn sys_task_info(_ti: *mut TaskInfo) -> isize {
+    -1
+}
+
+pub fn sys_set_priority(_prio: isize) -> isize {
+    -1
+}
+
+pub fn sys_mmap(_start: usize, _len: usize, _port: usize) -> isize {
+    -1
+}
+
+pub fn sys_munmap(_start: usize, _len: usize) -> isize {
+    -1
+}
+
+//
+// ALERT: 注意在实现 SPAWN 时不需要复制父进程地址空间，SPAWN != FORK + EXEC
+pub fn sys_spawn(_path: *const u8) -> isize {
+    -1
+}

os8-ref/src/syscall/sync.rs

@@ -0,0 +1,143 @@
+use crate::sync::{Condvar, Mutex, MutexBlocking, MutexSpin, Semaphore};
+use crate::task::{block_current_and_run_next, current_process, current_task};
+use crate::timer::{add_timer, get_time_ms};
+use alloc::sync::Arc;
+
+pub fn sys_sleep(ms: usize) -> isize {
+    let expire_ms = get_time_ms() + ms;
+    let task = current_task().unwrap();
+    add_timer(expire_ms, task);
+    block_current_and_run_next();
+    0
+}
+
+// LAB5 HINT: you might need to maintain data structures used for deadlock detection
+// during sys_mutex_* and sys_semaphore_* syscalls
+pub fn sys_mutex_create(blocking: bool) -> isize {
+    let process = current_process();
+    let mutex: Option<Arc<dyn Mutex>> = if !blocking {
+        Some(Arc::new(MutexSpin::new()))
+    } else {
+        Some(Arc::new(MutexBlocking::new()))
+    };
+    let mut process_inner = process.inner_exclusive_access();
+    if let Some(id) = process_inner
+        .mutex_list
+        .iter()
+        .enumerate()
+        .find(|(_, item)| item.is_none())
+        .map(|(id, _)| id)
+    {
+        process_inner.mutex_list[id] = mutex;
+        id as isize
+    } else {
+        process_inner.mutex_list.push(mutex);
+        process_inner.mutex_list.len() as isize - 1
+    }
+}
+
+// LAB5 HINT: Return -0xDEAD if deadlock is detected
+pub fn sys_mutex_lock(mutex_id: usize) -> isize {
+    let process = current_process();
+    let process_inner = process.inner_exclusive_access();
+    let mutex = Arc::clone(process_inner.mutex_list[mutex_id].as_ref().unwrap());
+    drop(process_inner);
+    drop(process);
+    mutex.lock();
+    0
+}
+
+pub fn sys_mutex_unlock(mutex_id: usize) -> isize {
+    let process = current_process();
+    let process_inner = process.inner_exclusive_access();
+    let mutex = Arc::clone(process_inner.mutex_list[mutex_id].as_ref().unwrap());
+    drop(process_inner);
+    drop(process);
+    mutex.unlock();
+    0
+}
+
+pub fn sys_semaphore_create(res_count: usize) -> isize {
+    let process = current_process();
+    let mut process_inner = process.inner_exclusive_access();
+    let id = if let Some(id) = process_inner
+        .semaphore_list
+        .iter()
+        .enumerate()
+        .find(|(_, item)| item.is_none())
+        .map(|(id, _)| id)
+    {
+        process_inner.semaphore_list[id] = Some(Arc::new(Semaphore::new(res_count)));
+        id
+    } else {
+        process_inner
+            .semaphore_list
+            .push(Some(Arc::new(Semaphore::new(res_count))));
+        process_inner.semaphore_list.len() - 1
+    };
+    id as isize
+}
+
+pub fn sys_semaphore_up(sem_id: usize) -> isize {
+    let process = current_process();
+    let process_inner = process.inner_exclusive_access();
+    let sem = Arc::clone(process_inner.semaphore_list[sem_id].as_ref().unwrap());
+    drop(process_inner);
+    sem.up();
+    0
+}
+
+// LAB5 HINT: Return -0xDEAD if deadlock is detected
+pub fn sys_semaphore_down(sem_id: usize) -> isize {
+    let process = current_process();
+    let process_inner = process.inner_exclusive_access();
+    let sem = Arc::clone(process_inner.semaphore_list[sem_id].as_ref().unwrap());
+    drop(process_inner);
+    sem.down();
+    0
+}
+
+pub fn sys_condvar_create(_arg: usize) -> isize {
+    let process = current_process();
+    let mut process_inner = process.inner_exclusive_access();
+    let id = if let Some(id) = process_inner
+        .condvar_list
+        .iter()
+        .enumerate()
+        .find(|(_, item)| item.is_none())
+        .map(|(id, _)| id)
+    {
+        process_inner.condvar_list[id] = Some(Arc::new(Condvar::new()));
+        id
+    } else {
+        process_inner
+            .condvar_list
+            .push(Some(Arc::new(Condvar::new())));
+        process_inner.condvar_list.len() - 1
+    };
+    id as isize
+}
+
+pub fn sys_condvar_signal(condvar_id: usize) -> isize {
+    let process = current_process();
+    let process_inner = process.inner_exclusive_access();
+    let condvar = Arc::clone(process_inner.condvar_list[condvar_id].as_ref().unwrap());
+    drop(process_inner);
+    condvar.signal();
+    0
+}
+
+pub fn sys_condvar_wait(condvar_id: usize, mutex_id: usize) -> isize {
+    let process = current_process();
+    let process_inner = process.inner_exclusive_access();
+    let condvar = Arc::clone(process_inner.condvar_list[condvar_id].as_ref().unwrap());
+    let mutex = Arc::clone(process_inner.mutex_list[mutex_id].as_ref().unwrap());
+    drop(process_inner);
+    condvar.wait(mutex);
+    0
+}
+
+// LAB5 YOUR JOB: Implement deadlock detection, but might not all in this syscall
+pub fn sys_enable_deadlock_detect(_enabled: usize) -> isize {
+    -1
+}

os8-ref/src/syscall/thread.rs

@@ -0,0 +1,86 @@
+use crate::{
+    mm::kernel_token,
+    task::{add_task, current_task, TaskControlBlock},
+    trap::{trap_handler, TrapContext},
+};
+use alloc::sync::Arc;
+
+pub fn sys_thread_create(entry: usize, arg: usize) -> isize {
+    let task = current_task().unwrap();
+    let process = task.process.upgrade().unwrap();
+    // create a new thread
+    let new_task = Arc::new(TaskControlBlock::new(
+        Arc::clone(&process),
+        task.inner_exclusive_access()
+            .res
+            .as_ref()
+            .unwrap()
+            .ustack_base,
+        true,
+    ));
+    let new_task_inner = new_task.inner_exclusive_access();
+    let new_task_res = new_task_inner.res.as_ref().unwrap();
+    let new_task_tid = new_task_res.tid;
+    let new_task_trap_cx = new_task_inner.get_trap_cx();
+    *new_task_trap_cx = TrapContext::app_init_context(
+        entry,
+        new_task_res.ustack_top(),
+        kernel_token(),
+        new_task.kernel_stack.get_top(),
+        trap_handler as usize,
+    );
+    (*new_task_trap_cx).x[10] = arg;
+
+    let mut process_inner = process.inner_exclusive_access();
+    // add new thread to current process
+    let tasks = &mut process_inner.tasks;
+    while tasks.len() < new_task_tid + 1 {
+        tasks.push(None);
+    }
+    tasks[new_task_tid] = Some(Arc::clone(&new_task));
+    // add new task to scheduler
+    add_task(Arc::clone(&new_task));
+    new_task_tid as isize
+}
+
+pub fn sys_gettid() -> isize {
+    current_task()
+        .unwrap()
+        .inner_exclusive_access()
+        .res
+        .as_ref()
+        .unwrap()
+        .tid as isize
+}
+
+/// thread does not exist, return -1
+/// thread has not exited yet, return -2
+/// otherwise, return thread's exit code
+pub fn sys_waittid(tid: usize) -> i32 {
+    let task = current_task().unwrap();
+    let process = task.process.upgrade().unwrap();
+    let task_inner = task.inner_exclusive_access();
+    let mut process_inner = process.inner_exclusive_access();
+    // a thread cannot wait for itself
+    if task_inner.res.as_ref().unwrap().tid == tid {
+        return -1;
+    }
+    let mut exit_code: Option<i32> = None;
+    let waited_task = process_inner.tasks[tid].as_ref();
+    if let Some(waited_task) = waited_task {
+        if let Some(waited_exit_code) = waited_task.inner_exclusive_access().exit_code {
+            exit_code = Some(waited_exit_code);
+        }
+    } else {
+        // waited thread does not exist
+        return -1;
+    }
+    if let Some(exit_code) = exit_code {
+        // dealloc the exited thread
+        process_inner.tasks[tid] = None;
+        exit_code
+    } else {
+        // waited thread has not exited
+        -2
+    }
+}