add bss init in executable

Author: Sharpiro

.clangd

@@ -13,3 +13,4 @@ CompileFlags:
     - -Wno-gnu-zero-variadic-macro-arguments
     - -Wno-gnu-statement-expression-from-macro-expansion
     - -Wvla
+    - -Wno-format-pedantic

.vscode/tasks.json

@@ -9,7 +9,14 @@
     {
       "label": "build_unit_test",
       "type": "shell",
-      "command": "make clean && CFLAGS='-DVERBOSE' make programs/linux/unit_test"
+      "dependsOn": ["build"],
+      "command": "programs/linux/unit_test"
+    },
+    {
+      "label": "run",
+      "type": "shell",
+      "dependsOn": ["build"],
+      "command": "./winloader ./windynamic.exe"
     }
   ]
 }

Makefile

@@ -12,7 +12,8 @@ WARNINGS = \
 	-Werror=return-type \
 	-Werror=incompatible-pointer-types \
 	-Wno-gnu-empty-initializer \
-	-Wvla
+	-Wvla \
+	-Wno-format-pedantic
 
 all: \
 	libtinyc.a \

src/dlls/msvcrt.c

@@ -180,6 +180,7 @@ static void fprintf_internal(
             print(file_handle, data);
             break;
         }
+        case 'p':
         case 'x': {
             size_t data = va_arg(var_args, size_t);
             print_number_hex(file_handle, data);

src/loader/win_loader_main.c

@@ -13,7 +13,10 @@
 CREATE_LIST_STRUCT(WinRuntimeObject)
 
 // @todo: hard-coding this may cause random program failures due to ASLR etc.
+// @todo: need smarter way of setting up IAT regions that don't conflict b/w
+//        exes & libs
 #define IAT_BASE_START 0x7d7e0000
+#define IAT_INCREMENT 0x10000
 
 struct WinRuntimeObject runtime_exe;
 struct RuntimeObject *lib_ntdll;
@@ -403,7 +406,7 @@ static bool initialize_lib_ntdll(struct RuntimeObject *lib_ntdll_object) {
 
     tiny_c_close(ntdll_file);
 
-    // @todo: computed not initialized
+    // @todo: bss, computed not initialized?
     uint8_t *bss = 0;
     size_t bss_len = 0;
     const struct SectionHeader *bss_section_header = find_section_header(
@@ -579,8 +582,21 @@ static bool initialize_dynamic_data(
             &iat_runtime_base
         );
         size_t iat_runtime_offset = current_iat_offset;
-        current_iat_base += 0x1000;
-        current_iat_offset += 0x1000;
+        current_iat_base += IAT_INCREMENT;
+        current_iat_offset += IAT_INCREMENT;
+
+        /* Init .bss */
+
+        // @todo: lib bss
+
+        // const struct WinSectionHeader *bss_header = find_win_section_header(
+        //     pe_exe.section_headers, pe_exe.section_headers_len, ".bss"
+        // );
+        // if (bss_header != NULL) {
+        //     uint8_t *bss_region =
+        //         (uint8_t *)(image_base + bss_header->base_address);
+        //     memset(bss_region, 0, bss_header->virtual_size);
+        // }
 
         struct WinRuntimeObject shared_lib = {
             .name = dir_entry->lib_name,
@@ -669,8 +685,8 @@ int main(int argc, char **argv) {
         (size_t)dynamic_callback_windows,
         &iat_runtime_base
     );
-    current_iat_base += 0x1000;
-    current_iat_offset += 0x1000;
+    current_iat_base += IAT_INCREMENT;
+    current_iat_offset += IAT_INCREMENT;
 
     /* Load libntdll.so */
 
@@ -679,6 +695,17 @@ int main(int argc, char **argv) {
         EXIT("initialize_lib_ntdll failed\n");
     }
 
+    /* Init .bss */
+
+    const struct WinSectionHeader *bss_header = find_win_section_header(
+        pe_exe.section_headers, pe_exe.section_headers_len, ".bss"
+    );
+    if (bss_header != NULL) {
+        uint8_t *bss_region =
+            (uint8_t *)(image_base + bss_header->base_address);
+        memset(bss_region, 0, bss_header->virtual_size);
+    }
+
     /* Load dlls */
 
     shared_libraries = (WinRuntimeObjectList){

src/programs/windows/win_dynamic/win_dynamic_main.c

@@ -1,12 +1,24 @@
 #include "../../../dlls/msvcrt.h"
 #include "../../../dlls/tinyc_stdio.h"
+#include <stdint.h>
 #include <stdlib.h>
 
+int32_t exe_global_var_bss = 0;
+int32_t exe_global_var_data = 42;
+
 int start_inferior() {
     int32_t num1 = (int32_t)pow(2, 4);
     int32_t num2 = (int32_t)pow(2, 4);
     printf("%d + %d = %d\n", num1, num2, num1 + num2);
 
+    printf("exe_global_var_bss: %d\n", exe_global_var_bss);
+    exe_global_var_bss = 1;
+    printf("exe_global_var_bss: %d\n", exe_global_var_bss);
+
+    printf("exe_global_var_data: %d\n", exe_global_var_data);
+    exe_global_var_data = 24;
+    printf("exe_global_var_data: %d\n", exe_global_var_data);
+
     return 0;
 }
 

test_winloader.sh

@@ -11,6 +11,10 @@ assert() {
 # Dynamic Test
 expected=`cat <<EOF
 16 + 16 = 32
+exe_global_var_bss: 0
+exe_global_var_bss: 1
+exe_global_var_data: 42
+exe_global_var_data: 24
 EOF
 `
 assert [ "`./winloader ./windynamic.exe`" == "$expected" ]