From 6497d71d2fb325dc052ed41192b52723e763bdb6 Mon Sep 17 00:00:00 2001
From: Mateusz Tabaka <tab.debugteam@gmail.com>
Date: Wed, 30 Dec 2020 18:14:53 +0100
Subject: [PATCH] Fix dlsym of TLS variables

---
 src/ld_so/dso.rs    |  2 ++
 src/ld_so/linker.rs | 29 +++++++++++++++++++++++++----
 src/ld_so/tcb.rs    |  8 ++++----
 3 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/src/ld_so/dso.rs b/src/ld_so/dso.rs
index 3f053d091e..f8e72d7ae6 100644
--- a/src/ld_so/dso.rs
+++ b/src/ld_so/dso.rs
@@ -358,12 +358,14 @@ impl DSO {
                         base: mmap.as_ptr() as usize,
                         value: sym.st_value as usize,
                         size: sym.st_size as usize,
+                        sym_type: sym::st_type(sym.st_info),
                     }
                 } else {
                     Symbol {
                         base: 0,
                         value: sym.st_value as usize,
                         size: sym.st_size as usize,
+                        sym_type: sym::st_type(sym.st_info),
                     }
                 };
             } else {
diff --git a/src/ld_so/linker.rs b/src/ld_so/linker.rs
index 21d35b1804..f90bdb41ef 100644
--- a/src/ld_so/linker.rs
+++ b/src/ld_so/linker.rs
@@ -6,14 +6,18 @@ use alloc::{
 };
 use core::{cell::RefCell, mem::transmute, ptr};
 use goblin::{
-    elf::{program_header, reloc, Elf},
+    elf::{program_header, reloc, sym::STT_TLS, Elf},
     error::{Error, Result},
 };
 
 use crate::{
     c_str::CString,
     fs::File,
-    header::{fcntl, sys_mman, unistd::F_OK},
+    header::{
+        dl_tls::{__tls_get_addr, dl_tls_index},
+        fcntl, sys_mman,
+        unistd::F_OK,
+    },
     io::Read,
     platform::types::c_void,
 };
@@ -32,6 +36,7 @@ pub struct Symbol {
     pub value: usize,
     pub base: usize,
     pub size: usize,
+    pub sym_type: u8,
 }
 
 impl Symbol {
@@ -91,8 +96,24 @@ impl Linker {
 
     pub fn get_sym(&self, lib_id: usize, name: &str) -> Option<*mut c_void> {
         match self.objects.get(&lib_id) {
-            Some(obj) => obj.get_sym(name).map(|s| s.as_ptr()),
-            _ => None,
+            Some(obj) => {
+                return obj.get_sym(name).map(|s| {
+                    if s.sym_type != STT_TLS {
+                        s.as_ptr()
+                    } else {
+                        unsafe {
+                            let mut tls_index = dl_tls_index {
+                                ti_module: obj.tls_module_id as u64,
+                                ti_offset: s.value as u64,
+                            };
+                            __tls_get_addr(&mut tls_index)
+                        }
+                    }
+                });
+            }
+            _ => {
+                return None;
+            }
         }
     }
 
diff --git a/src/ld_so/tcb.rs b/src/ld_so/tcb.rs
index 0ff9e557d3..152486aa50 100644
--- a/src/ld_so/tcb.rs
+++ b/src/ld_so/tcb.rs
@@ -40,7 +40,7 @@ pub struct Tcb {
     /// Size of the masters list in bytes (multiple of mem::size_of::<Master>())
     pub masters_len: usize,
     /// Index of last copied Master
-    pub last_master_copied: usize,
+    pub num_copied_masters: usize,
     /// Pointer to dynamic linker
     pub linker_ptr: *const Mutex<Linker>,
     /// pointer to rust memory allocator structure
@@ -63,7 +63,7 @@ impl Tcb {
                 tcb_len: tcb_page.len(),
                 masters_ptr: ptr::null_mut(),
                 masters_len: 0,
-                last_master_copied: 0,
+                num_copied_masters: 0,
                 linker_ptr: ptr::null(),
                 mspace: 0,
             },
@@ -114,7 +114,7 @@ impl Tcb {
             if let Some(masters) = self.masters() {
                 for (i, master) in masters
                     .iter()
-                    .skip(self.last_master_copied)
+                    .skip(self.num_copied_masters)
                     .filter(|m| m.len > 0)
                     .enumerate()
                 {
@@ -135,7 +135,7 @@ impl Tcb {
                         return Err(Error::Malformed(format!("failed to copy tls master {}", i)));
                     }
                 }
-                self.last_master_copied = masters.len();
+                self.num_copied_masters = masters.len();
             }
         }