From 327a6b5e307bcf63670e77ccbd206dd7d007005d Mon Sep 17 00:00:00 2001
From: Fabing Li <lifabing.lfb@antgroup.com>
Date: Tue, 19 Nov 2024 11:37:35 +0800
Subject: [PATCH] Export /proc/self-thread

---
 kernel/src/fs/procfs/mod.rs         | 16 +++++++++++++---
 kernel/src/fs/procfs/pid/task.rs    |  4 ++++
 kernel/src/fs/procfs/thread_self.rs | 29 +++++++++++++++++++++++++++++
 3 files changed, 46 insertions(+), 3 deletions(-)
 create mode 100644 kernel/src/fs/procfs/thread_self.rs

diff --git a/kernel/src/fs/procfs/mod.rs b/kernel/src/fs/procfs/mod.rs
index f8524218a..c1f120933 100644
--- a/kernel/src/fs/procfs/mod.rs
+++ b/kernel/src/fs/procfs/mod.rs
@@ -3,15 +3,16 @@
 use core::sync::atomic::{AtomicU64, Ordering};
 
 use filesystems::{FileSystemType, FILESYSTEM_TYPES};
-use loadavg::LoadAvgFileOps;
-use sys::SysDirOps;
 
 use self::{
     cpuinfo::CpuInfoFileOps,
+    loadavg::LoadAvgFileOps,
     meminfo::MemInfoFileOps,
     pid::PidDirOps,
     self_::SelfSymOps,
+    sys::SysDirOps,
     template::{DirOps, ProcDir, ProcDirBuilder, ProcSymBuilder, SymOps},
+    thread_self::ThreadSelfSymOps,
 };
 use crate::{
     events::Observer,
@@ -20,7 +21,10 @@ use crate::{
         utils::{DirEntryVecExt, FileSystem, FsFlags, Inode, SuperBlock, NAME_MAX},
     },
     prelude::*,
-    process::{process_table, process_table::PidEvent, Pid},
+    process::{
+        process_table::{self, PidEvent},
+        Pid,
+    },
 };
 
 mod cpuinfo;
@@ -31,6 +35,7 @@ mod pid;
 mod self_;
 mod sys;
 mod template;
+mod thread_self;
 
 pub(super) fn init() {
     FILESYSTEM_TYPES.call_once(|| {
@@ -119,6 +124,8 @@ impl DirOps for RootDirOps {
             SelfSymOps::new_inode(this_ptr.clone())
         } else if name == "sys" {
             SysDirOps::new_inode(this_ptr.clone())
+        } else if name == "thread-self" {
+            ThreadSelfSymOps::new_inode(this_ptr.clone())
         } else if name == "filesystems" {
             FileSystemsFileOps::new_inode(this_ptr.clone())
         } else if name == "meminfo" {
@@ -144,6 +151,9 @@ impl DirOps for RootDirOps {
         };
         let mut cached_children = this.cached_children().write();
         cached_children.put_entry_if_not_found("self", || SelfSymOps::new_inode(this_ptr.clone()));
+        cached_children.put_entry_if_not_found("thread-self", || {
+            ThreadSelfSymOps::new_inode(this_ptr.clone())
+        });
         cached_children.put_entry_if_not_found("sys", || SysDirOps::new_inode(this_ptr.clone()));
         cached_children.put_entry_if_not_found("filesystems", || {
             FileSystemsFileOps::new_inode(this_ptr.clone())
diff --git a/kernel/src/fs/procfs/pid/task.rs b/kernel/src/fs/procfs/pid/task.rs
index 9a4be525c..65b1676be 100644
--- a/kernel/src/fs/procfs/pid/task.rs
+++ b/kernel/src/fs/procfs/pid/task.rs
@@ -40,6 +40,7 @@ impl DirOps for ThreadDirOps {
     fn lookup_child(&self, this_ptr: Weak<dyn Inode>, name: &str) -> Result<Arc<dyn Inode>> {
         let inode = match name {
             "fd" => FdDirOps::new_inode(self.0.clone(), this_ptr.clone()),
+            "exe" => ExeSymOps::new_inode(self.0.clone(), this_ptr.clone()),
             _ => return_errno!(Errno::ENOENT),
         };
         Ok(inode)
@@ -54,6 +55,9 @@ impl DirOps for ThreadDirOps {
         cached_children.put_entry_if_not_found("fd", || {
             FdDirOps::new_inode(self.0.clone(), this_ptr.clone())
         });
+        cached_children.put_entry_if_not_found("exe", || {
+            ExeSymOps::new_inode(self.0.clone(), this_ptr.clone())
+        });
     }
 }
 
diff --git a/kernel/src/fs/procfs/thread_self.rs b/kernel/src/fs/procfs/thread_self.rs
new file mode 100644
index 000000000..1e1adb3ef
--- /dev/null
+++ b/kernel/src/fs/procfs/thread_self.rs
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: MPL-2.0
+
+use alloc::format;
+
+use crate::{
+    fs::{
+        procfs::{ProcSymBuilder, SymOps},
+        utils::Inode,
+    },
+    prelude::*,
+    process::posix_thread::AsPosixThread,
+};
+
+/// Represents the inode at `/proc/self-thread`.
+pub struct ThreadSelfSymOps;
+
+impl ThreadSelfSymOps {
+    pub fn new_inode(parent: Weak<dyn Inode>) -> Arc<dyn Inode> {
+        ProcSymBuilder::new(Self).parent(parent).build().unwrap()
+    }
+}
+
+impl SymOps for ThreadSelfSymOps {
+    fn read_link(&self) -> Result<String> {
+        let pid = current!().pid();
+        let tid = current_thread!().as_posix_thread().unwrap().tid();
+        Ok(format!("{}/task/{}", pid, tid))
+    }
+}