From 144f824f17c1f368342ab024c1ac728fac0055a7 Mon Sep 17 00:00:00 2001
From: Jason Ish <jason.ish@oisf.net>
Date: Wed, 27 May 2026 17:17:22 -0600
Subject: [PATCH] rust/ffi: add thread init callback wrapper

Ticket: #8605
---
 examples/plugins/rust/src/mod.rs | 12 +++++++
 rust/ffi/src/lib.rs              |  1 +
 rust/ffi/src/thread.rs           | 55 ++++++++++++++++++++++++++++++++
 3 files changed, 68 insertions(+)
 create mode 100644 rust/ffi/src/thread.rs

diff --git a/examples/plugins/rust/src/mod.rs b/examples/plugins/rust/src/mod.rs
index 96ba63ea3f..f41b21ec69 100644
--- a/examples/plugins/rust/src/mod.rs
+++ b/examples/plugins/rust/src/mod.rs
@@ -3,6 +3,7 @@ use std::ptr::null_mut;
 use suricata_ffi::eve::{self, SCJsonBuilder};
 use suricata_ffi::flow;
 use suricata_ffi::jsonbuilder::JsonBuilder;
+use suricata_ffi::thread;
 use suricata_ffi::{SCLogError, SCLogNotice};
 use suricata_sys::sys::{Flow, Packet, SCEveRegisterCallback, SCPlugin, ThreadVars};
 
@@ -16,6 +17,9 @@ unsafe extern "C" fn init() {
     if let Err(err) = register_flow_callbacks() {
         SCLogError!("Failed to register rust example flow callbacks: {}", err);
     }
+    if let Err(err) = register_thread_callbacks() {
+        SCLogError!("Failed to register rust example thread callbacks: {}", err);
+    }
 }
 
 fn register_eve_callbacks() -> Result<(), &'static str> {
@@ -32,6 +36,10 @@ fn register_flow_callbacks() -> Result<(), &'static str> {
     Ok(())
 }
 
+pub fn register_thread_callbacks() -> Result<(), &'static str> {
+    thread::register_init_callback(on_thread_init)
+}
+
 unsafe extern "C" fn log_eve_raw(
     _tv: *mut ThreadVars,
     _p: *const Packet,
@@ -58,6 +66,10 @@ fn log_eve_wrapped(
     Ok(())
 }
 
+fn on_thread_init(tv: *mut ThreadVars) {
+    SCLogNotice!("rust example thread init callback: thread={:p}", tv);
+}
+
 fn log_flow_init(_tv: *mut ThreadVars, _f: *mut Flow, _p: *const Packet) {
     SCLogNotice!("rust example flow init callback: flow={:p}", _f);
 }
diff --git a/rust/ffi/src/lib.rs b/rust/ffi/src/lib.rs
index 5203abb2ee..b9ca52d328 100644
--- a/rust/ffi/src/lib.rs
+++ b/rust/ffi/src/lib.rs
@@ -24,6 +24,7 @@ pub mod eve;
 pub mod flow;
 pub mod jsonbuilder;
 pub mod plugin;
+pub mod thread;
 
 pub const IPPROTO_TCP: u8 = 6;
 pub const IPPROTO_UDP: u8 = 17;
diff --git a/rust/ffi/src/thread.rs b/rust/ffi/src/thread.rs
new file mode 100644
index 0000000000..c2ed145c7f
--- /dev/null
+++ b/rust/ffi/src/thread.rs
@@ -0,0 +1,55 @@
+/* Copyright (C) 2026 Open Information Security Foundation
+ *
+ * You can copy, redistribute or modify this Program under the terms of
+ * the GNU General Public License version 2 as published by the Free
+ * Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+use std::os::raw::c_void;
+
+use suricata_sys::sys::{SCThreadRegisterInitCallback, ThreadVars};
+
+/// Register a thread initialization callback.
+///
+/// The callback is invoked for every thread being initialized during Suricata
+/// startup. It receives the `ThreadVars` for the thread that has just been
+/// initialized.
+///
+/// # Safety
+///
+/// The callback receives a raw pointer from Suricata. This pointer is only
+/// valid for the duration of the callback invocation and must not be stored.
+///
+/// The callback must not panic.
+pub fn register_init_callback<F>(callback: F) -> Result<(), &'static str>
+where
+    F: Fn(*mut ThreadVars) + Send + Sync + 'static,
+{
+    let user = Box::into_raw(Box::new(callback)) as *mut c_void;
+    if unsafe { SCThreadRegisterInitCallback(Some(init_callback_wrapper::<F>), user) } {
+        Ok(())
+    } else {
+        unsafe {
+            drop(Box::from_raw(user as *mut F));
+        }
+        Err("Failed to register thread init callback")
+    }
+}
+
+unsafe extern "C" fn init_callback_wrapper<F>(tv: *mut ThreadVars, user: *mut c_void)
+where
+    F: Fn(*mut ThreadVars) + Send + Sync + 'static,
+{
+    let callback = &*(user as *const F);
+    callback(tv);
+}