fix：修复用户态进入，还有一些路径映射问题

os/src/fs/proc/inode.rs

@@ -176,7 +176,7 @@ impl ProcInode {
             metadata: SpinLock::new(InodeMetadata {
                 inode_no,
                 inode_type: InodeType::Symlink,
-                mode: FileMode::from_bits_truncate(0o777),
+                mode: FileMode::from_bits_truncate(0o777 | FileMode::S_IFLNK.bits()),
                 uid: 0,
                 gid: 0,
                 size: target.len(),
@@ -211,7 +211,7 @@ impl ProcInode {
             metadata: SpinLock::new(InodeMetadata {
                 inode_no,
                 inode_type: InodeType::Symlink,
-                mode: FileMode::from_bits_truncate(0o777),
+                mode: FileMode::from_bits_truncate(0o777 | FileMode::S_IFLNK.bits()),
                 uid: 0,
                 gid: 0,
                 size: 0, // 动态链接的大小未知

os/src/kernel/syscall/task/clone_ops.rs

@@ -46,6 +46,7 @@ pub fn clone(
         fs,
         uts,
         rlimit,
+        exe_path,
     ) = {
         let _guard = crate::sync::PreemptGuard::new();
         let cpu = current_cpu();
@@ -66,6 +67,7 @@ pub fn clone(
             task.fs.clone(),
             task.uts_namespace.clone(),
             task.rlimit.clone(),
+            task.exe_path.clone(),
         )
     };
     let exit_signal = requested_flags.get_exit_signal();
@@ -132,6 +134,7 @@ pub fn clone(
         fd_table,
         fs,
     );
+    child_task.exe_path = exe_path;
 
     if requested_flags.contains(CloneFlags::CHILD_SETTID) {
         unsafe {

os/src/kernel/syscall/task/exec_ops.rs

@@ -41,7 +41,7 @@ pub fn execve(
             Err(_) => return -EIO,
         };
         if meta.inode_type != crate::vfs::InodeType::File {
-            return -EISDIR;
+            return exec_non_file_errno(meta.inode_type);
         }
 
         let prefix_len = core::cmp::min(meta.size, 256);
@@ -173,6 +173,13 @@ fn parse_hashbang(data: &[u8]) -> Result<(&str, Option<&str>), HashbangError> {
     Ok((interpreter_path, interpreter_arg))
 }
 
+// 按 POSIX/Linux 语义：对非普通文件（含目录）调用 execve 一律返回 EACCES。
+// 真实内核 may_open() 对 S_IFDIR + MAY_EXEC 返回 -EACCES；EISDIR 仅用于写目录等场景。
+// busybox/bash 拿到 EACCES 后会自行处理（bash 会 stat 后输出 "Is a directory"）。
+fn exec_non_file_errno(_inode_type: crate::vfs::InodeType) -> c_int {
+    -EACCES
+}
+
 /// 执行一个新程序（execve）的准备阶段：解析 ELF 并创建新的地址空间
 fn do_execve_prepare(
     path: &str,
@@ -181,6 +188,9 @@ fn do_execve_prepare(
         Ok(p) => p,
         Err(crate::kernel::task::ExecImageError::Fs(FsError::NotFound)) => return Err(-ENOENT),
         Err(crate::kernel::task::ExecImageError::Fs(FsError::IsDirectory)) => return Err(-EISDIR),
+        Err(crate::kernel::task::ExecImageError::NotRegular(inode_type)) => {
+            return Err(exec_non_file_errno(inode_type));
+        }
         Err(crate::kernel::task::ExecImageError::Fs(_)) => return Err(-EIO),
         Err(crate::kernel::task::ExecImageError::Paging(
             crate::mm::page_table::PagingError::OutOfMemory,

os/src/kernel/syscall/task/mod.rs

@@ -30,8 +30,8 @@ use crate::{
     sync::SpinLock,
     uapi::{
         errno::{
-            EAGAIN, EFAULT, EINTR, EINVAL, EIO, EISDIR, ENOENT, ENOEXEC, ENOMEM, ENOSYS, EPERM,
-            ESRCH, ETIMEDOUT,
+            EACCES, EAGAIN, EFAULT, EINTR, EINVAL, EIO, EISDIR, ENOENT, ENOEXEC, ENOMEM, ENOSYS,
+            EPERM, ESRCH, ETIMEDOUT,
         },
         futex::{FUTEX_CLOCK_REALTIME, FUTEX_PRIVATE, FUTEX_WAIT, FUTEX_WAKE, RobustListHead},
         resource::{RLIM_NLIMITS, Rlimit, Rusage},

os/src/kernel/task/exec_loader.rs

@@ -13,6 +13,7 @@ use crate::vfs::{FsError, Inode, InodeType};
 pub enum ExecImageError {
     Fs(FsError),
     InvalidElf,
+    NotRegular(InodeType),
     Paging(PagingError),
 }
 
@@ -429,7 +430,7 @@ pub fn prepare_exec_image_from_path(path: &str) -> Result<PreparedExecImage, Exe
     let inode = dentry.inode.clone();
     let meta = inode.metadata().map_err(ExecImageError::from)?;
     if meta.inode_type != InodeType::File {
-        return Err(ExecImageError::Fs(FsError::IsDirectory));
+        return Err(ExecImageError::NotRegular(meta.inode_type));
     }
 
     let eh = parse_elf_header(inode.as_ref())?;
@@ -479,7 +480,7 @@ pub fn prepare_exec_image_from_path(path: &str) -> Result<PreparedExecImage, Exe
         let interp_inode = interp_dentry.inode.clone();
         let interp_meta = interp_inode.metadata().map_err(ExecImageError::from)?;
         if interp_meta.inode_type != InodeType::File {
-            return Err(ExecImageError::InvalidElf);
+            return Err(ExecImageError::NotRegular(interp_meta.inode_type));
         }
 
         let interp_eh = parse_elf_header(interp_inode.as_ref())?;

os/src/kernel/task/task_struct.rs

@@ -2,10 +2,7 @@
 //!
 //! 包含任务的核心信息，如上下文、状态、内存空间等
 #![allow(dead_code)]
-use core::{
-    mem::size_of,
-    sync::atomic::{AtomicPtr, Ordering},
-};
+use core::sync::atomic::{AtomicPtr, Ordering};
 
 use alloc::{string::String, sync::Arc, vec::Vec};
 
@@ -20,7 +17,7 @@ use crate::{
         task::{forkret, task_state::TaskState},
     },
     mm::{
-        address::{ConvertablePA, PageNum, UA, VA},
+        address::{ConvertablePA, PageNum, UA, UsizeConvert, VA},
         frame_allocator::{FrameRangeTracker, FrameTracker},
         memory_space::MemorySpace,
     },
@@ -309,8 +306,12 @@ impl Task {
         // 4. 配置 TrapFrame (新的上下文)
         // SAFETY: tfptr 指向的内存已经被分配且可写，并由 task 拥有
         unsafe {
-            // 清零整个 TrapFrame，避免旧值泄漏到用户态
-            core::ptr::write_bytes(tf_ptr, 0, size_of::<TrapFrame>());
+            // 原先：清零整个 TrapFrame，避免旧值泄漏到用户态。
+            // 注意：write_bytes 的 count 以 TrapFrame 为单位（非字节），
+            // 这里只清零 1 个 TrapFrame。若误传 size_of::<TrapFrame>()，
+            // 会写 280*280 字节、越界冲掉当前 satp 指向的页表，导致静默死循环。
+            // 由于 set_exec_trap_frame 内部已 *self = Self::zero_init() 全量清零，
+            // 这行 write_bytes 在功能上完全冗余，故直接删除
             <TrapFrame as HwTrapFrame>::set_exec_trap_frame_from_layout(
                 &mut *tf_ptr,
                 initial_pc.as_usize(),

os/src/vfs/adapter.rs

@@ -12,7 +12,7 @@ impl Stat {
         Self {
             st_dev: 0, // TODO: 需要从文件系统获取设备号
             st_ino: meta.inode_no as u64,
-            st_mode: meta.mode.bits(),
+            st_mode: mode_with_type(meta),
             st_nlink: meta.nlinks as u32,
             st_uid: meta.uid,
             st_gid: meta.gid,
@@ -50,7 +50,7 @@ impl Statx {
             stx_nlink: meta.nlinks as u32,
             stx_uid: meta.uid,
             stx_gid: meta.gid,
-            stx_mode: meta.mode.bits() as u16,
+            stx_mode: mode_with_type(meta) as u16,
             __spare0: [0; 1],
             stx_ino: meta.inode_no as u64,
             stx_size: meta.size as u64,
@@ -72,6 +72,23 @@ impl Statx {
     }
 }
 
+fn mode_with_type(meta: &InodeMetadata) -> u32 {
+    let mode = meta.mode.bits();
+    if mode & crate::vfs::FileMode::S_IFMT.bits() != 0 {
+        return mode;
+    }
+
+    mode | match meta.inode_type {
+        InodeType::File => crate::vfs::FileMode::S_IFREG.bits(),
+        InodeType::Directory => crate::vfs::FileMode::S_IFDIR.bits(),
+        InodeType::Symlink => crate::vfs::FileMode::S_IFLNK.bits(),
+        InodeType::CharDevice => crate::vfs::FileMode::S_IFCHR.bits(),
+        InodeType::BlockDevice => crate::vfs::FileMode::S_IFBLK.bits(),
+        InodeType::Fifo => crate::vfs::FileMode::S_IFIFO.bits(),
+        InodeType::Socket => crate::vfs::FileMode::S_IFSOCK.bits(),
+    }
+}
+
 /// 将InodeType转换为d_type值
 pub fn inode_type_to_d_type(t: InodeType) -> u8 {
     match t {