Add hook macro & std::string api for C

Author: ReallocAll

CMakeLists.txt

@@ -16,8 +16,9 @@ set(MODLOADER_VERSION "Preview 3")
 add_subdirectory(dep/funchook)
 
 add_library(server_modloader SHARED include/modloader/hook.h include/modloader/statichook.h include/modloader/log.h
-        include/modloader/loader.h
-        src/hook.cpp src/log.cpp src/loader.h src/loader.cpp src/elf_helper.cpp src/elf_helper.h src/main.cpp)
+        include/modloader/loader.h include/modloader/cutils.h
+        src/hook.cpp src/log.cpp src/loader.h src/loader.cpp src/elf_helper.cpp src/elf_helper.h src/main.cpp
+        src/cutils.cpp)
 target_link_libraries(server_modloader funchook)
 target_compile_definitions(server_modloader PRIVATE MODLOADER_VERSION="${MODLOADER_VERSION}")
 target_include_directories(server_modloader PUBLIC include/)

include/modloader/cutils.h

@@ -0,0 +1,96 @@
+#ifndef MODLOADER_CUTILS_H
+#define MODLOADER_CUTILS_H
+
+#include <modloader/hook.h>
+
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <string.h>
+
+#ifndef RTLD_DEFAULT
+#define RTLD_DEFAULT NULL
+#endif
+
+#define SYM(sym)                                            \
+    dlsym(RTLD_DEFAULT, sym)
+
+
+#define SYMCALL(sym, func_proto, ...)                       \
+    ((func_proto)                                           \
+    (SYM(sym)))                                             \
+    (__VA_ARGS__)
+
+
+#define VIRTUAL_CALL(ptr, func_proto, ...)                  \
+    ((func_proto)                                           \
+    ((void *)ptr))                                          \
+    (__VA_ARGS__)
+
+
+#define DEREFERENCE(type, ptr, offset)                      \
+    (*(type*)((uintptr_t)ptr + offset))
+
+
+#define REFERENCE(type, ptr, offset)                        \
+    (type*)((uintptr_t)ptr + offset)
+
+
+// for uintptr_t
+#define PTR_OFFSET(ptr, offset)                             \
+    ((uintptr_t)ptr + offset)
+
+
+#define THOOK(name, ret_type, sym, ...)          		    \
+    typedef ret_type (*_##name##_t)(__VA_ARGS__);           \
+    _##name##_t _original_##name = NULL;                    \
+    ret_type _detour_##name(__VA_ARGS__);                   \
+    void _install_##name(void) __attribute__((constructor));\
+    void _destroy_##name(void);                             \
+                                                            \
+    struct _##name {                                        \
+        _##name##_t hook;                                   \
+        _##name##_t detour;                                 \
+        _##name##_t original;                               \
+        void (*install)(void);                              \
+        void (*destroy)(void);                              \
+    } name = {NULL, NULL, NULL,                             \
+                _install_##name, _destroy_##name};          \
+                                                            \
+    void _install_##name(void)                              \
+    {                                                       \
+        modloader_hook_t *_hook_##name =                    \
+                            modloader_hook(SYM(sym),        \
+                                _detour_##name,             \
+                                (void**)&_original_##name); \
+        name.hook = _hook_##name;                           \
+        name.detour = _detour_##name;                       \
+        name.original = _original_##name;                   \
+    }                                                       \
+                                                            \
+    void _destroy_##name(void)                              \
+    {                                                       \
+        modloader_destroy_hook(name.hook);                  \
+    }                                                       \
+                                                            \
+    ret_type _detour_##name(__VA_ARGS__)
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+// std::string::basic_string(const char *c_str)
+void *std_string_string(const char *c_str);
+
+// std::string::c_str()
+const char *std_string_c_str(void *str);
+
+// std::string::~basic_string()
+void std_string_destroy(void *str);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

src/cutils.cpp

@@ -0,0 +1,17 @@
+#include <modloader/cutils.h>
+#include <string>
+
+void *std_string_string(const char *c_str) {
+    auto str = new std::string;
+    str->assign(c_str);
+	return (void*)str;
+}
+
+const char *std_string_c_str(void *str) {
+	return ((std::string*)str)->c_str();
+}
+
+void std_string_destroy(void *str) {
+    ((std::string*)str)->~basic_string();
+    delete (std::string*)str;
+}