From 59090a83f4f5d1112361a8cfc054a5d21612e8f7 Mon Sep 17 00:00:00 2001
From: 4lDO2 <4lDO2@protonmail.com>
Date: Mon, 31 Mar 2025 15:17:11 +0200
Subject: [PATCH] Fix thread+proc fd init in ld.so

---
 src/ld_so/linker.rs |  9 ++++++---
 src/ld_so/mod.rs    |  4 ++++
 src/ld_so/start.rs  | 27 +++++++++++++++++++++------
 3 files changed, 31 insertions(+), 9 deletions(-)

diff --git a/src/ld_so/linker.rs b/src/ld_so/linker.rs
index a1a429090d..ca55590d4f 100644
--- a/src/ld_so/linker.rs
+++ b/src/ld_so/linker.rs
@@ -612,10 +612,13 @@ impl Linker {
         unsafe {
             if !dlopened {
                 #[cfg(target_os = "redox")]
-                let (tcb, old_tcb) = {
+                let (tcb, old_tcb, thr_fd) = {
                     use redox_rt::signal::tmp_disable_signals;
 
                     let old_tcb = Tcb::current().expect("failed to get bootstrap TCB");
+                    let thr_fd = (&mut *old_tcb.os_specific.thr_fd.get())
+                        .take()
+                        .expect("no thread FD present");
                     let new_tcb = Tcb::new(self.tls_size)?; // This actually allocates TCB, TLS and ABI page.
 
                     // Stash
@@ -653,7 +656,7 @@ impl Linker {
                     new_tcb.generic.tcb_len = new_tcb_len;
 
                     drop(_guard);
-                    (new_tcb, old_tcb as *mut Tcb as *mut c_void)
+                    (new_tcb, old_tcb as *mut Tcb as *mut c_void, thr_fd)
                 };
 
                 #[cfg(not(target_os = "redox"))]
@@ -694,7 +697,7 @@ impl Linker {
                 tcb.copy_masters().map_err(|_| DlError::Malformed)?;
                 tcb.activate(
                     #[cfg(target_os = "redox")]
-                    todo!(),
+                    thr_fd,
                 );
 
                 #[cfg(target_os = "redox")]
diff --git a/src/ld_so/mod.rs b/src/ld_so/mod.rs
index d3d726df5d..425d04d859 100644
--- a/src/ld_so/mod.rs
+++ b/src/ld_so/mod.rs
@@ -196,6 +196,10 @@ pub unsafe fn init(
             #[cfg(target_os = "redox")]
             thr_fd,
         );
+    } else {
+        // The thread fd must already be present in the already existing TCB. Don't close it.
+        #[cfg(target_os = "redox")]
+        core::mem::forget(thr_fd);
     }
 }
 
diff --git a/src/ld_so/start.rs b/src/ld_so/start.rs
index 4c09f52f34..390a77c09a 100644
--- a/src/ld_so/start.rs
+++ b/src/ld_so/start.rs
@@ -145,16 +145,31 @@ fn resolve_path_name(
     None
 }
 
-// TODO: Make unsafe
 #[no_mangle]
-pub extern "C" fn relibc_ld_so_start(sp: &'static mut Stack, ld_entry: usize) -> usize {
+pub unsafe extern "C" fn relibc_ld_so_start(sp: &'static mut Stack, ld_entry: usize) -> usize {
     // Setup TCB for ourselves.
     unsafe {
-        let tcb = Tcb::new(0).expect_notls("ld.so: failed to allocate bootstrap TCB");
-        tcb.activate(todo!());
-
         #[cfg(target_os = "redox")]
-        redox_rt::signal::setup_sighandler(&tcb.os_specific);
+        let thr_fd =
+            crate::platform::get_auxv_raw(sp.auxv().cast(), redox_rt::auxv_defs::AT_REDOX_THR_FD)
+                .expect_notls("no thread fd present");
+
+        let tcb = Tcb::new(0).expect_notls("ld.so: failed to allocate bootstrap TCB");
+        tcb.activate(
+            #[cfg(target_os = "redox")]
+            redox_rt::proc::FdGuard::new(thr_fd),
+        );
+        #[cfg(target_os = "redox")]
+        {
+            let proc_fd = crate::platform::get_auxv_raw(
+                sp.auxv().cast(),
+                redox_rt::auxv_defs::AT_REDOX_PROC_FD,
+            )
+            .expect_notls("no proc fd present");
+
+            redox_rt::initialize(redox_rt::proc::FdGuard::new(proc_fd));
+            redox_rt::signal::setup_sighandler(&tcb.os_specific);
+        }
     }
 
     // We get the arguments, the environment, and the auxilary vector