feat: 实现并测试 newfstatat 系统调用 (#1153)

* feat: 实现并测试 newfstatat 系统调用

新增了 newfstatat 系统调用的实现，并添加了相应的测试应用。

Signed-off-by: longjin <longjin@DragonOS.org>

* feat(loongarch64/riscv64): 添加文件系统模块并实现GenericPosixStat结构

为loongarch64和riscv64架构添加filesystem模块，包含stat子模块，并实现GenericPosixStat结构用于处理文件状态信息。

Signed-off-by: longjin <longjin@DragonOS.org>

---------

Signed-off-by: longjin <longjin@DragonOS.org>

kernel/src/arch/loongarch64/filesystem/mod.rs

@@ -0,0 +1 @@
+pub mod stat;

kernel/src/arch/loongarch64/filesystem/stat.rs

@@ -0,0 +1 @@
+pub use crate::filesystem::vfs::stat::GenericPosixStat as PosixStat;

kernel/src/arch/loongarch64/mod.rs

@@ -1,6 +1,7 @@
 pub mod asm;
 pub mod cpu;
 pub mod elf;
+pub mod filesystem;
 pub mod init;
 pub mod interrupt;
 pub mod ipc;

kernel/src/arch/riscv64/filesystem/mod.rs

@@ -0,0 +1 @@
+pub mod stat;

kernel/src/arch/riscv64/filesystem/stat.rs

@@ -0,0 +1 @@
+pub use crate::filesystem::vfs::stat::GenericPosixStat as PosixStat;

kernel/src/arch/riscv64/mod.rs

@@ -2,6 +2,7 @@ pub mod asm;
 pub mod cpu;
 pub mod driver;
 pub mod elf;
+pub mod filesystem;
 pub mod init;
 pub mod interrupt;
 pub mod ipc;

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

@@ -0,0 +1 @@
+pub mod stat;

kernel/src/arch/x86_64/filesystem/stat.rs

@@ -0,0 +1,72 @@
+use system_error::SystemError;
+
+use crate::filesystem::vfs::stat::KStat;
+
+#[repr(C)]
+#[derive(Default, Clone, Copy)]
+pub struct PosixStat {
+    pub st_dev: usize,
+    pub st_ino: usize,
+    pub st_nlink: usize,
+    pub st_mode: u32,
+    pub st_uid: u32,
+    pub st_gid: u32,
+    pub __pad0: u32,
+    pub st_rdev: usize,
+    pub st_size: isize,
+    pub st_blksize: isize,
+    /// number of 512B blocks allocated
+    pub st_blocks: isize,
+    pub st_atime: usize,
+    pub st_atime_nsec: usize,
+    pub st_mtime: usize,
+    pub st_mtime_nsec: usize,
+    pub st_ctime: usize,
+    pub st_ctime_nsec: usize,
+    pub __unused: [isize; 3],
+}
+
+/// 转换的代码参考 https://code.dragonos.org.cn/xref/linux-6.6.21/fs/stat.c#393
+impl TryFrom<KStat> for PosixStat {
+    type Error = SystemError;
+
+    fn try_from(kstat: KStat) -> Result<Self, Self::Error> {
+        let mut tmp = PosixStat::default();
+        if core::mem::size_of_val(&tmp.st_dev) < 4 && !kstat.dev.old_valid_dev() {
+            return Err(SystemError::EOVERFLOW);
+        }
+        if core::mem::size_of_val(&tmp.st_rdev) < 4 && !kstat.rdev.old_valid_dev() {
+            return Err(SystemError::EOVERFLOW);
+        }
+
+        tmp.st_dev = kstat.dev.new_encode_dev() as usize;
+        tmp.st_ino = kstat.ino as usize;
+
+        if core::mem::size_of_val(&tmp.st_ino) < core::mem::size_of_val(&kstat.ino)
+            && tmp.st_ino != kstat.ino as usize
+        {
+            return Err(SystemError::EOVERFLOW);
+        }
+
+        tmp.st_mode = kstat.mode.bits();
+        tmp.st_nlink = kstat.nlink.try_into().map_err(|_| SystemError::EOVERFLOW)?;
+
+        // todo: 处理user namespace (https://code.dragonos.org.cn/xref/linux-6.6.21/fs/stat.c#415)
+        tmp.st_uid = kstat.uid;
+        tmp.st_gid = kstat.gid;
+
+        tmp.st_rdev = kstat.rdev.data() as usize;
+        tmp.st_size = kstat.size as isize;
+
+        tmp.st_atime = kstat.atime.tv_sec as usize;
+        tmp.st_mtime = kstat.mtime.tv_sec as usize;
+        tmp.st_ctime = kstat.ctime.tv_sec as usize;
+        tmp.st_atime_nsec = kstat.atime.tv_nsec as usize;
+        tmp.st_mtime_nsec = kstat.mtime.tv_nsec as usize;
+        tmp.st_ctime_nsec = kstat.ctime.tv_nsec as usize;
+        tmp.st_blocks = kstat.blocks as isize;
+        tmp.st_blksize = kstat.blksize as isize;
+
+        Ok(tmp)
+    }
+}

kernel/src/arch/x86_64/mod.rs

@@ -4,6 +4,7 @@ mod acpi;
 pub mod cpu;
 pub mod driver;
 pub mod elf;
+pub mod filesystem;
 pub mod fpu;
 pub mod init;
 pub mod interrupt;