Fixes

* Fix incorrenctly handling TLS offsets for subsequent libraries; now
  correctly relocating indices relative to the TLS region
* Improve TLS example even more
* A bit more cleanup

include/compartment.h

@@ -147,8 +147,6 @@ struct LibDependency
     void *tls_sec_addr;
     size_t tls_sec_size;
     size_t tls_data_size;
-    unsigned short tls_vars_count;
-    unsigned int tls_vars_idx_start;
 };
 
 /**

src/compartment.c

@@ -223,6 +223,7 @@ comp_map(struct Compartment *to_map)
         err(1, "Error mapping compartment %zu scratch memory", to_map->id);
     }
 
+    size_t tls_allocd = 0x0;
     for (size_t i = 0; i < to_map->libs_count; ++i)
     {
         // Bind `.got.plt` entries
@@ -237,14 +238,15 @@ comp_map(struct Compartment *to_map)
                 &to_map->libs[i]->rela_maps[j].target_func_address,
                 sizeof(void *));
         }
+
         // Map .tdata sections
         if (to_map->libs[i]->tls_data_size != 0)
         {
             assert(to_map->libs[i]->tls_sec_addr);
             // TODO why sizeof(void*) ?
-            memcpy((char *) to_map->libs_tls_sects->region_start
-                    + sizeof(void *) * to_map->libs[i]->tls_vars_idx_start,
+            memcpy((char *) to_map->libs_tls_sects->region_start + tls_allocd,
                 to_map->libs[i]->tls_sec_addr, to_map->libs[i]->tls_data_size);
+            tls_allocd += to_map->libs[i]->tls_sec_size;
         }
     }
 
@@ -441,8 +443,6 @@ parse_lib_file(char *lib_name, struct Compartment *new_comp)
     new_lib->tls_sec_addr = 0x0;
     new_lib->tls_sec_size = 0;
     new_lib->tls_data_size = 0;
-    new_lib->tls_vars_count = 0;
-    new_lib->tls_vars_idx_start = 0;
 
     parse_lib_segs(&lib_ehdr, lib_fd, new_lib, new_comp);
 
@@ -548,8 +548,6 @@ parse_lib_segs(Elf64_Ehdr *lib_ehdr, int lib_fd, struct LibDependency *lib_dep,
             }
             lib_dep->tls_sec_addr = (void *) lib_phdr.p_vaddr;
             lib_dep->tls_sec_size = lib_phdr.p_memsz;
-            // TODO check
-            lib_dep->tls_vars_count = lib_phdr.p_memsz / lib_phdr.p_align;
         }
 
         if (lib_phdr.p_type != PT_LOAD)
@@ -877,14 +875,22 @@ static void
 resolve_rela_syms(struct Compartment *new_comp)
 {
     // Find all symbols for eager relocation mapping
+    size_t prev_tls_secs_size = 0;
     for (size_t i = 0; i < new_comp->libs_count; ++i)
     {
         for (size_t j = 0; j < new_comp->libs[i]->rela_maps_count; ++j)
         {
             struct LibRelaMapping *curr_rela_map
                 = &new_comp->libs[i]->rela_maps[j];
-            if (curr_rela_map->target_func_address != 0
-                || curr_rela_map->rela_sym_type == STT_TLS)
+
+            if (curr_rela_map->rela_sym_type == STT_TLS)
+            {
+                curr_rela_map->target_func_address = (char*)
+                    curr_rela_map->target_func_address + prev_tls_secs_size;
+                continue;
+            }
+
+            if (curr_rela_map->target_func_address != 0)
             {
                 continue;
             }
@@ -921,6 +927,7 @@ resolve_rela_syms(struct Compartment *new_comp)
             curr_rela_map->target_func_address
                 = extract_sym_offset(new_comp, found_sym);
         }
+        prev_tls_secs_size += new_comp->libs[i]->tls_sec_size;
     }
 }
 
@@ -968,9 +975,7 @@ find_lib_dep_sym_in_comp(const char *to_find,
             cond = cond
                 && comp_to_search->libs[i]->lib_syms[j].sym_type == sym_type;
 
-            // Symbols of type `TLS` could have valid 0-offset values; but
-            // other symbols cannot - basically a pseudo-check that this is a
-            // valid, defined symbol to relocate against
+            // Symbols cannot have 0-offset values
             if (sym_type != STT_TLS)
             {
                 cond = cond
@@ -1068,7 +1073,6 @@ resolve_comp_tls_regions(struct Compartment *new_comp)
     unsigned short *lib_idxs
         = malloc(new_comp->libs_count * sizeof(unsigned short));
     unsigned short actual_idxs = 0;
-    size_t tls_vars = 0;
     size_t comp_tls_size = 0;
     for (size_t i = 0; i < new_comp->libs_count; ++i)
     {
@@ -1079,9 +1083,6 @@ resolve_comp_tls_regions(struct Compartment *new_comp)
         comp_tls_size += new_comp->libs[i]->tls_sec_size;
         new_comp->libs_tls_sects->libs_count += 1;
 
-        new_comp->libs[i]->tls_vars_idx_start = tls_vars;
-        tls_vars += new_comp->libs[i]->tls_vars_count;
-
         lib_idxs[actual_idxs] = i;
         actual_idxs += 1;
     }

tests/simple_thrloc_var-external.c

@@ -3,6 +3,7 @@
 _Thread_local int ex_val;
 _Thread_local int ex_val_used;
 _Thread_local static int ex_val_stat = 242;
+_Thread_local int from_int;
 
 int
 get_ext()
@@ -23,3 +24,10 @@ use_val()
     ex_val_used = 24;
     assert(ex_val_used == 24);
 }
+
+void
+do_ext_check(int val)
+{
+    from_int = val;
+    assert(from_int == ex_val_stat);
+}

tests/simple_thrloc_var.c

@@ -4,9 +4,13 @@
 _Thread_local int val;
 _Thread_local static int val2 = 4242;
 _Thread_local static int val3 = INT_MAX;
+_Thread_local static long val4 = LONG_MAX;
+_Thread_local long val5;
 
-int
-get_ext();
+int get_ext();
+int get_ext_stat();
+void use_val();
+void do_ext_check(int);
 
 int
 do_val2()
@@ -22,7 +26,17 @@ main(void)
     int i = do_val2();
     assert(val == 42);
     assert(i == 4242);
-    val = val3;
+    assert(val3 == INT_MAX);
+    long v4_local = val4;
+    assert(v4_local == LONG_MAX);
+    val5 = 21;
+    assert(val5 * 2 == val);
+
+    // Check external library functions
     assert(get_ext() == 420);
+    assert(get_ext_stat() == 242);
+    do_ext_check(242);
+    use_val();
+
     return 0;
 }