added origin arg for tiny_interpose

Author: Antibioticss

include/tinyhook.h

@@ -30,7 +30,7 @@ TH_VIS int tiny_unhook_ex(const th_bak_t *bak);
 TH_VIS int tiny_insert(void *address, void *destination);
 
 /* interpose */
-TH_VIS int tiny_interpose(uint32_t image_index, const char *symbol_name, void *replacement);
+TH_VIS int tiny_interpose(uint32_t image_index, const char *symbol_name, void *replacement, void **origin);
 
 /* objective-c runtime */
 TH_VIS int ocrt_hook(const char *cls, const char *sel, void *destination, void **origin);

src/interpose.c

@@ -10,7 +10,7 @@
     #include <mach/mach_error.h> // mach_error_string()
 #endif
 
-int tiny_interpose(uint32_t image_index, const char *symbol_name, void *replacement) {
+int tiny_interpose(uint32_t image_index, const char *symbol_name, void *replacement, void **origin) {
     intptr_t image_slide = _dyld_get_image_vmaddr_slide(image_index);
     struct mach_header_64 *mh_header = (struct mach_header_64 *)_dyld_get_image_header(image_index);
     struct load_command *ld_command = (void *)mh_header + sizeof(struct mach_header_64);
@@ -84,6 +84,8 @@ int tiny_interpose(uint32_t image_index, const char *symbol_name, void *replacem
                         break;
                     }
                 }
+                if (origin != NULL)
+                    *origin = sym_ptrs[j];
                 sym_ptrs[j] = replacement;
                 break;
             }

test/hook/example.c

@@ -64,7 +64,7 @@ __attribute__((constructor(0))) int load() {
 
     // or use interpose to hook it!
     fprintf(stderr, "=== Now interposing printf\n");
-    tiny_interpose(0, "_printf", printf_interpose);
+    tiny_interpose(0, "_printf", printf_interpose, NULL);
     return 0;
 }