实现free指令+修复 mountfs的内存泄露问题(#394)

* 实现meminfo文件

* 成功实现free指令，添加了一些string有关函数，并进行一些无影响的小改动


* 解决内存泄露的问题：mountfs inode的wrap方法使用了Arc::into_raw而没有from_raw，导致inode始终无法释放

---------

Co-authored-by: LoGin <longjin@DragonOS.org>
Co-authored-by: longjin <longjin@RinGoTek.cn>

kernel/src/arch/x86_64/mm/mod.rs

@@ -14,7 +14,7 @@ use crate::libs::lib_ui::screen_manager::scm_disable_put_to_window;
 use crate::libs::printk::PrintkWriter;
 use crate::libs::spinlock::SpinLock;
 
-use crate::mm::allocator::page_frame::{FrameAllocator, PageFrameCount};
+use crate::mm::allocator::page_frame::{FrameAllocator, PageFrameCount, PageFrameUsage};
 use crate::mm::mmio_buddy::mmio_init;
 use crate::{
     arch::MMArch,
@@ -512,10 +512,7 @@ pub fn test_buddy() {
 pub struct LockedFrameAllocator;
 
 impl FrameAllocator for LockedFrameAllocator {
-    unsafe fn allocate(
-        &mut self,
-        count: crate::mm::allocator::page_frame::PageFrameCount,
-    ) -> Option<(PhysAddr, PageFrameCount)> {
+    unsafe fn allocate(&mut self, count: PageFrameCount) -> Option<(PhysAddr, PageFrameCount)> {
         if let Some(ref mut allocator) = *INNER_ALLOCATOR.lock_irqsave() {
             return allocator.allocate(count);
         } else {
@@ -523,19 +520,25 @@ impl FrameAllocator for LockedFrameAllocator {
         }
     }
 
-    unsafe fn free(
-        &mut self,
-        address: crate::mm::PhysAddr,
-        count: crate::mm::allocator::page_frame::PageFrameCount,
-    ) {
+    unsafe fn free(&mut self, address: crate::mm::PhysAddr, count: PageFrameCount) {
         assert!(count.data().is_power_of_two());
         if let Some(ref mut allocator) = *INNER_ALLOCATOR.lock_irqsave() {
             return allocator.free(address, count);
         }
     }
 
-    unsafe fn usage(&self) -> crate::mm::allocator::page_frame::PageFrameUsage {
-        todo!()
+    unsafe fn usage(&self) -> PageFrameUsage {
+        if let Some(ref mut allocator) = *INNER_ALLOCATOR.lock_irqsave() {
+            return allocator.usage();
+        } else {
+            panic!("usage error");
+        }
+    }
+}
+
+impl LockedFrameAllocator {
+    pub fn get_usage(&self) -> PageFrameUsage {
+        unsafe { self.usage() }
     }
 }
 

kernel/src/filesystem/devfs/mod.rs

@@ -562,7 +562,7 @@ pub fn devfs_init() -> Result<(), SystemError> {
     static INIT: Once = Once::new();
     let mut result = None;
     INIT.call_once(|| {
-        kinfo!("Initializing ProcFS...");
+        kinfo!("Initializing DevFS...");
         // 创建 devfs 实例
         let devfs: Arc<DevFS> = DevFS::new();
         // devfs 挂载

kernel/src/filesystem/procfs/mod.rs

@@ -10,6 +10,7 @@ use alloc::{
 };
 
 use crate::{
+    arch::mm::LockedFrameAllocator,
     filesystem::vfs::{
         core::{generate_inode_id, ROOT_INODE},
         FileType,
@@ -37,6 +38,8 @@ use super::vfs::{
 pub enum ProcFileType {
     ///展示进程状态信息
     ProcStatus = 0,
+    /// meminfo
+    ProcMeminfo = 1,
     //todo: 其他文件类型
     ///默认文件类型
     Default,
@@ -46,6 +49,7 @@ impl From<u8> for ProcFileType {
     fn from(value: u8) -> Self {
         match value {
             0 => ProcFileType::ProcStatus,
+            1 => ProcFileType::ProcMeminfo,
             _ => ProcFileType::Default,
         }
     }
@@ -204,8 +208,34 @@ impl ProcFSInode {
         return Ok((pdata.len() * size_of::<u8>()) as i64);
     }
 
-    /// status文件读取函数
-    fn read_status(
+    /// 打开 meminfo 文件
+    fn open_meminfo(&self, pdata: &mut ProcfsFilePrivateData) -> Result<i64, SystemError> {
+        // 获取内存信息
+        let usage = LockedFrameAllocator.get_usage();
+
+        // 传入数据
+        let data: &mut Vec<u8> = &mut pdata.data;
+
+        data.append(
+            &mut format!("MemTotal:\t{} kB\n", usage.total().bytes() >> 10)
+                .as_bytes()
+                .to_owned(),
+        );
+
+        data.append(
+            &mut format!("MemFree:\t{} kB\n", usage.free().bytes() >> 10)
+                .as_bytes()
+                .to_owned(),
+        );
+
+        // 去除多余的\0
+        self.trim_string(data);
+
+        return Ok((data.len() * size_of::<u8>()) as i64);
+    }
+
+    /// proc文件系统读取函数
+    fn proc_read(
         &self,
         offset: usize,
         len: usize,
@@ -263,7 +293,7 @@ impl ProcFS {
                     mtime: TimeSpec::default(),
                     ctime: TimeSpec::default(),
                     file_type: FileType::Dir,
-                    mode: ModeType::from_bits_truncate(0o777),
+                    mode: ModeType::from_bits_truncate(0o555),
                     nlinks: 1,
                     uid: 0,
                     gid: 0,
@@ -286,6 +316,24 @@ impl ProcFS {
         // 释放锁
         drop(root_guard);
 
+        // 创建meminfo文件
+        let inode = result.root_inode();
+        let binding = inode.create(
+            "meminfo",
+            FileType::File,
+            ModeType::from_bits_truncate(0o444),
+        );
+        if let Ok(meminfo) = binding {
+            let meminfo_file = meminfo
+                .as_any_ref()
+                .downcast_ref::<LockedProcFSInode>()
+                .unwrap();
+            meminfo_file.0.lock().fdata.pid = Pid::new(0);
+            meminfo_file.0.lock().fdata.ftype = ProcFileType::ProcMeminfo;
+        } else {
+            panic!("create meminfo error");
+        }
+
         return result;
     }
 
@@ -293,26 +341,26 @@ impl ProcFS {
     /// @usage 在进程中调用并创建进程对应文件
     pub fn register_pid(&self, pid: Pid) -> Result<(), SystemError> {
         // 获取当前inode
-        let proc: Arc<dyn IndexNode> = self.root_inode();
+        let inode: Arc<dyn IndexNode> = self.root_inode();
         // 创建对应进程文件夹
-        let _pf: Arc<dyn IndexNode> = proc.create(
+        let pid_dir: Arc<dyn IndexNode> = inode.create(
             &pid.to_string(),
             FileType::Dir,
-            ModeType::from_bits_truncate(0o777),
+            ModeType::from_bits_truncate(0o555),
         )?;
         // 创建相关文件
         // status文件
-        let binding: Arc<dyn IndexNode> = _pf.create(
+        let binding: Arc<dyn IndexNode> = pid_dir.create(
             "status",
             FileType::File,
-            ModeType::from_bits_truncate(0o777),
+            ModeType::from_bits_truncate(0o444),
         )?;
-        let _sf: &LockedProcFSInode = binding
+        let status_file: &LockedProcFSInode = binding
             .as_any_ref()
             .downcast_ref::<LockedProcFSInode>()
             .unwrap();
-        _sf.0.lock().fdata.pid = pid;
-        _sf.0.lock().fdata.ftype = ProcFileType::ProcStatus;
+        status_file.0.lock().fdata.pid = pid;
+        status_file.0.lock().fdata.ftype = ProcFileType::ProcStatus;
 
         //todo: 创建其他文件
 
@@ -352,6 +400,7 @@ impl IndexNode for LockedProcFSInode {
         // 根据文件类型获取相应数据
         let file_size = match inode.fdata.ftype {
             ProcFileType::ProcStatus => inode.open_status(&mut private_data)?,
+            ProcFileType::ProcMeminfo => inode.open_meminfo(&mut private_data)?,
             _ => {
                 todo!()
             }
@@ -409,7 +458,8 @@ impl IndexNode for LockedProcFSInode {
 
         // 根据文件类型读取相应数据
         match inode.fdata.ftype {
-            ProcFileType::ProcStatus => return inode.read_status(offset, len, buf, private_data),
+            ProcFileType::ProcStatus => return inode.proc_read(offset, len, buf, private_data),
+            ProcFileType::ProcMeminfo => return inode.proc_read(offset, len, buf, private_data),
             ProcFileType::Default => (),
         };
 
@@ -720,10 +770,10 @@ pub fn procfs_init() -> Result<(), SystemError> {
     let mut result = None;
     INIT.call_once(|| {
         kinfo!("Initializing ProcFS...");
-        // 创建 sysfs 实例
+        // 创建 procfs 实例
         let procfs: Arc<ProcFS> = ProcFS::new();
 
-        // sysfs 挂载
+        // procfs 挂载
         let _t = ROOT_INODE()
             .find("proc")
             .expect("Cannot find /proc")

kernel/src/filesystem/vfs/file.rs

@@ -261,7 +261,6 @@ impl File {
             self.readdir_subdirs_name = inode.list()?;
             self.readdir_subdirs_name.sort();
         }
-
         // kdebug!("sub_entries={sub_entries:?}");
         if self.readdir_subdirs_name.is_empty() {
             self.offset = 0;
@@ -513,6 +512,7 @@ impl FileDescriptorVec {
 
         // 把文件描述符数组对应位置设置为空
         let file = self.fds[fd as usize].take().unwrap();
+
         assert!(Arc::strong_count(&file) == 1);
         return Ok(());
     }

kernel/src/filesystem/vfs/mount.rs

@@ -63,11 +63,11 @@ impl MountFS {
         let weak: Weak<MountFS> = Arc::downgrade(&mount_fs);
 
         // 将Arc指针转为Raw指针并对其内部的self_ref字段赋值
-        let ptr: *mut MountFS = Arc::into_raw(mount_fs) as *mut Self;
+        let ptr: *mut MountFS = mount_fs.as_ref() as *const Self as *mut Self;
         unsafe {
             (*ptr).self_ref = weak;
             // 返回初始化好的MountFS对象
-            return Arc::from_raw(ptr);
+            return mount_fs;
         }
     }
 
@@ -97,7 +97,7 @@ impl MountFSInode {
         let weak: Weak<MountFSInode> = Arc::downgrade(&inode);
         // 将Arc指针转为Raw指针并对其内部的self_ref字段赋值
         compiler_fence(Ordering::SeqCst);
-        let ptr: *mut MountFSInode = Arc::into_raw(inode.clone()) as *mut Self;
+        let ptr: *mut MountFSInode = inode.as_ref() as *const Self as *mut Self;
         compiler_fence(Ordering::SeqCst);
         unsafe {
             (*ptr).self_ref = weak;

kernel/src/filesystem/vfs/syscall.rs

@@ -184,6 +184,7 @@ impl Syscall {
         }
 
         // 创建文件对象
+
         let mut file: File = File::new(inode, mode)?;
 
         // 打开模式为“追加”
@@ -210,7 +211,9 @@ impl Syscall {
         let binding = ProcessManager::current_pcb().fd_table();
         let mut fd_table_guard = binding.write();
 
-        return fd_table_guard.drop_fd(fd as i32).map(|_| 0);
+        let res = fd_table_guard.drop_fd(fd as i32).map(|_| 0);
+
+        return res;
     }
 
     /// @brief 根据文件描述符，读取文件数据。尝试读取的数据长度与buf的长度相同。
@@ -389,7 +392,10 @@ impl Syscall {
 
         // drop guard 以避免无法调度的问题
         drop(fd_table_guard);
-        return file.lock_no_preempt().readdir(dirent).map(|x| x as usize);
+
+        let res = file.lock_no_preempt().readdir(dirent).map(|x| x as usize);
+
+        return res;
     }
 
     /// @brief 创建文件夹

kernel/src/mm/allocator/buddy.rs

@@ -65,6 +65,8 @@ impl<A> PageList<A> {
 pub struct BuddyAllocator<A> {
     // 存放每个阶的空闲“链表”的头部地址
     free_area: [PhysAddr; (MAX_ORDER - MIN_ORDER) as usize],
+    /// 总页数
+    total: PageFrameCount,
     phantom: PhantomData<A>,
 }
 
@@ -227,9 +229,9 @@ impl<A: MemoryManagementArch> BuddyAllocator<A> {
         assert!(remain_bytes == 0);
         assert!(paddr == initial_bump_offset + pages_to_buddy.data() * A::PAGE_SIZE);
 
-        // Self::print_free_area(free_area);
         let allocator = Self {
             free_area,
+            total: pages_to_buddy,
             phantom: PhantomData,
         };
 
@@ -357,7 +359,6 @@ impl<A: MemoryManagementArch> BuddyAllocator<A> {
             }
             return None;
         };
-
         let result: Option<PhysAddr> = alloc_in_specific_order(order as u8);
         // kdebug!("result={:?}", result);
         if result.is_some() {
@@ -662,7 +663,19 @@ impl<A: MemoryManagementArch> FrameAllocator for BuddyAllocator<A> {
     }
 
     unsafe fn usage(&self) -> PageFrameUsage {
-        todo!("BuddyAllocator::usage")
+        let mut free_page_num: usize = 0;
+        for index in 0..(MAX_ORDER - MIN_ORDER) {
+            let mut pagelist: PageList<A> = Self::read_page(self.free_area[index]);
+            loop {
+                free_page_num += pagelist.entry_num << index;
+                if pagelist.next_page.is_null() {
+                    break;
+                }
+                pagelist = Self::read_page(pagelist.next_page);
+            }
+        }
+        let free = PageFrameCount::new(free_page_num);
+        PageFrameUsage::new(self.total - free, self.total)
     }
 }
 

kernel/src/mm/allocator/page_frame.rs

@@ -273,7 +273,7 @@ impl PageFrameUsage {
     }
     // @brief 获取空闲的页帧数量
     pub fn free(&self) -> PageFrameCount {
-        return PageFrameCount(self.total.0 - self.used.0);
+        return self.total - self.used;
     }
     // @brief 获取总的页帧数量
     pub fn total(&self) -> PageFrameCount {

kernel/src/syscall/mod.rs

@@ -417,9 +417,9 @@ impl Syscall {
                     Err(SystemError::EINVAL)
                 } else {
                     let path: &str = path.unwrap();
+
                     let flags = args[1];
                     let open_flags: FileMode = FileMode::from_bits_truncate(flags as u32);
-
                     Self::open(path, open_flags)
                 };
 
@@ -427,7 +427,10 @@ impl Syscall {
             }
             SYS_CLOSE => {
                 let fd = args[0];
-                Self::close(fd)
+
+                let res = Self::close(fd);
+
+                res
             }
             SYS_READ => {
                 let fd = args[0] as i32;
@@ -545,6 +548,7 @@ impl Syscall {
 
             SYS_GET_DENTS => {
                 let fd = args[0] as i32;
+
                 let buf_vaddr = args[1];
                 let len = args[2];
                 let virt_addr: VirtAddr = VirtAddr::new(buf_vaddr);