From 4702aaa37ce8c6c007c46a5144a62a93159bc1ae Mon Sep 17 00:00:00 2001
From: oiupoyt <oiupoyt.cat@gmail.com>
Date: Tue, 29 Sep 2026 17:07:14 +0530
Subject: [PATCH] feat(core): implement Bionic TLS block allocation and TCB
 self-pointer setup

---
 crates/molotov-core/src/lib.rs        |  1 +
 crates/molotov-core/src/tls.rs        | 41 +++++++++++++++++++++++++++
 crates/molotov-core/tests/tls_test.rs |  9 ++++++
 3 files changed, 51 insertions(+)
 create mode 100644 crates/molotov-core/src/tls.rs
 create mode 100644 crates/molotov-core/tests/tls_test.rs

diff --git a/crates/molotov-core/src/lib.rs b/crates/molotov-core/src/lib.rs
index 51bc3ae..cdf6125 100644
--- a/crates/molotov-core/src/lib.rs
+++ b/crates/molotov-core/src/lib.rs
@@ -4,4 +4,5 @@ pub mod elf;
 pub mod mmap;
 pub mod reloc;
 pub mod symbols;
+pub mod tls;
 pub mod trampoline;
diff --git a/crates/molotov-core/src/tls.rs b/crates/molotov-core/src/tls.rs
new file mode 100644
index 0000000..0179472
--- /dev/null
+++ b/crates/molotov-core/src/tls.rs
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+use std::alloc::{alloc_zeroed, dealloc, Layout};
+
+pub const BIONIC_TLS_SLOTS: usize = 128;
+
+pub struct BionicTls {
+    ptr: *mut u64,
+    layout: Layout,
+}
+
+impl BionicTls {
+    pub fn allocate() -> Result<Self, String> {
+        let layout = Layout::from_size_align(BIONIC_TLS_SLOTS * std::mem::size_of::<u64>(), 64)
+            .map_err(|e| e.to_string())?;
+
+        let ptr = unsafe { alloc_zeroed(layout) as *mut u64 };
+        if ptr.is_null() {
+            Err("Failed to allocate memory for Bionic TLS".to_string())
+        } else {
+            // Android x86_64: slot 0 points to the thread control block itself
+            unsafe {
+                *ptr = ptr as u64;
+            }
+            Ok(Self { ptr, layout })
+        }
+    }
+
+    pub fn tcb_ptr(&self) -> *mut u64 {
+        self.ptr
+    }
+}
+
+impl Drop for BionicTls {
+    fn drop(&mut self) {
+        if !self.ptr.is_null() {
+            unsafe {
+                dealloc(self.ptr as *mut u8, self.layout);
+            }
+        }
+    }
+}
diff --git a/crates/molotov-core/tests/tls_test.rs b/crates/molotov-core/tests/tls_test.rs
new file mode 100644
index 0000000..a789f2d
--- /dev/null
+++ b/crates/molotov-core/tests/tls_test.rs
@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+use molotov_core::tls::BionicTls;
+
+#[test]
+fn test_bionic_tls_allocation() {
+    let tls = BionicTls::allocate().expect("Bionic TLS block should allocate cleanly");
+    assert!(!tls.tcb_ptr().is_null());
+    assert_eq!(tls.tcb_ptr() as usize % 64, 0, "TLS pointer must be 64-byte aligned");
+}