added test

CMakeLists.txt

@@ -14,7 +14,15 @@ add_library(mach_detours SHARED
         src/arm64/detours_arm64.h
         src/arm64/detours_arm64_disasm.cpp
 )
-
 target_include_directories(mach_detours
-        PUBLIC "include"
+        PUBLIC include
-        PRIVATE "src")
+        PRIVATE src
+)
+
+
+add_executable(mach_detours_sample
+        sample/main.cpp
+)
+target_link_libraries(mach_detours_sample
+        PRIVATE mach_detours
+)

include/mach_detours.h

@@ -5,6 +5,10 @@
 #ifndef MACH_DETOURS_H
 #define MACH_DETOURS_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include <mach/error.h>
 #include <mach/mach_types.h>
 
@@ -31,4 +35,8 @@ bool detour_set_retain_regions(bool value);
 void* detour_set_system_region_lower_bound(void* value);
 void* detour_set_system_region_upper_bound(void* value);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif // MACH_DETOURS_H

sample/main.cpp

@@ -0,0 +1,34 @@
+// Copyright (c) Lysann Tranvouez.  All rights reserved.
+
+#include <cassert>
+
+#include "mach_detours.h"
+
+#include <cstring>
+
+char* (*real_strerror)(int errno) = strerror;
+
+static int counter = 0;
+
+char* my_strerror(const int errno)
+{
+    counter++;
+    return real_strerror(errno);
+}
+
+int main(int argc, const char* argv[])
+{
+    counter = 0;
+    strerror(0);
+    assert(counter == 0);
+
+    detour_transaction_begin();
+    detour_attach(reinterpret_cast<detour_func_t*>(&real_strerror), reinterpret_cast<detour_func_t>(my_strerror));
+    detour_transaction_commit();
+
+    assert(counter == 0);
+    strerror(0);
+    assert(counter == 1);
+
+    return 0;
+}

src/mach_detours.c

@@ -3,7 +3,7 @@
 
 #include "mach_detours.h"
 
-#define DETOUR_DEBUG 1
+#define DETOUR_DEBUG 0
 
 #ifdef __arm64__
 #define DETOURS_ARM64
@@ -200,12 +200,11 @@ static detour_trampoline* internal_detour_alloc_trampoline(uint8_t* target)
     // First check the default region for a valid free block.
     if (s_default_region && s_default_region->free_list_head &&
         s_default_region->free_list_head >= lo && s_default_region->free_list_head <= hi) {
-
     found_region:
         trampoline = s_default_region->free_list_head;
         // do a last sanity check on region.
         if (trampoline < lo || trampoline > hi) {
-            raise(SIGTRAP);
+            DETOUR_BREAK();
             return nullptr;
         }
         s_default_region->free_list_head = (detour_trampoline*)trampoline->ptr_remain;
@@ -522,9 +521,8 @@ mach_error_t detour_transaction_commit_ex(detour_func_t** out_failed_target)
                     if (pc >= targetAddr && pc < targetAddr + op->trampoline->restore_code_size) {
                         uintptr_t new_pc = (uintptr_t)op->trampoline;
                         new_pc += internal_detour_align_from_target(op->trampoline, pc - targetAddr);
-                        printf("detours: thread %u was at 0x%" PRIXPTR ", moved to 0x%" PRIXPTR "\n", thread->thread,
+                        DETOUR_TRACE(("detours: thread %u was at 0x%" PRIXPTR ", moved to 0x%" PRIXPTR "\n",
-                               pc,
+                            thread->thread, pc, new_pc));
-                               new_pc);
                         arm_thread_state64_set_pc_fptr(threadState, new_pc);
                         thread_set_state(thread->thread, ARM_THREAD_STATE64, (thread_state_t)&threadState,
                                          ARM_THREAD_STATE64_COUNT);
@@ -536,9 +534,8 @@ mach_error_t detour_transaction_commit_ex(detour_func_t** out_failed_target)
                     if (pc >= trampAddr && pc < trampAddr + sizeof(*op->trampoline)) {
                         uintptr_t new_pc = (uintptr_t)op->target;
                         new_pc += internal_detour_align_from_trampoline(op->trampoline, pc - trampAddr);
-                        printf("detours: thread %u was at 0x%" PRIXPTR ", moved to 0x%" PRIXPTR "\n", thread->thread,
+                        DETOUR_TRACE(("detours: thread %u was at 0x%" PRIXPTR ", moved to 0x%" PRIXPTR "\n",
-                               pc,
+                            thread->thread, pc, new_pc));
-                               new_pc);
                         arm_thread_state64_set_pc_fptr(threadState, new_pc);
                         thread_set_state(thread->thread, ARM_THREAD_STATE64, (thread_state_t)&threadState,
                                          ARM_THREAD_STATE64_COUNT);
@@ -648,7 +645,8 @@ mach_error_t detour_attach(detour_func_t* inout_pointer, detour_func_t detour)
     return detour_attach_ex(inout_pointer, detour, nullptr, nullptr, nullptr);
 }
 
-mach_error_t detour_attach_ex(detour_func_t* inout_pointer, detour_func_t detour, detour_func_t* out_real_trampoline, detour_func_t* out_real_target, detour_func_t* out_real_detour)
+mach_error_t detour_attach_ex(detour_func_t* inout_pointer, detour_func_t detour, detour_func_t* out_real_trampoline,
+                              detour_func_t* out_real_target, detour_func_t* out_real_detour)
 {
     if (out_real_trampoline) {
         *out_real_trampoline = nullptr;
@@ -844,7 +842,8 @@ mach_error_t detour_attach_ex(detour_func_t* inout_pointer, detour_func_t detour
 
     trampoline_code = trampoline->code + trampoline->code_size;
 
-    trampoline_code = internal_detour_gen_jmp_immediate(trampoline_code, &trampoline_code_limit, trampoline->ptr_remain);
+    trampoline_code =
+        internal_detour_gen_jmp_immediate(trampoline_code, &trampoline_code_limit, trampoline->ptr_remain);
     trampoline_code = internal_detour_gen_brk(trampoline_code, trampoline_code_limit);
     UNUSED_VARIABLE(trampoline_code);
 
@@ -857,7 +856,8 @@ mach_error_t detour_attach_ex(detour_func_t* inout_pointer, detour_func_t detour
         mach_vm_size_t region_size = 0;
         natural_t nesting_depth = 99999;
         mach_msg_type_number_t count = VM_REGION_SUBMAP_SHORT_INFO_COUNT_64;
-        error = mach_vm_region_recurse(port, &region_addr, &region_size, &nesting_depth, (vm_region_recurse_info_t)&region_info, &count);
+        error = mach_vm_region_recurse(port, &region_addr, &region_size, &nesting_depth,
+                                       (vm_region_recurse_info_t)&region_info, &count);
         if (error != err_none) {
             DETOUR_BREAK();
             goto fail;
@@ -976,7 +976,8 @@ mach_error_t detour_detach(detour_func_t* inout_pointer, detour_func_t detour)
         mach_vm_size_t region_size = 0;
         natural_t nesting_depth = 99999;
         mach_msg_type_number_t count = VM_REGION_SUBMAP_SHORT_INFO_COUNT_64;
-        error = mach_vm_region_recurse(port, &region_addr, &region_size, &nesting_depth, (vm_region_recurse_info_t)&region_info, &count);
+        error = mach_vm_region_recurse(port, &region_addr, &region_size, &nesting_depth,
+                                       (vm_region_recurse_info_t)&region_info, &count);
         if (error != err_none) {
             DETOUR_BREAK();
             goto fail;
@@ -984,7 +985,8 @@ mach_error_t detour_detach(detour_func_t* inout_pointer, detour_func_t detour)
     }
     const vm_prot_t old_perm = region_info.protection;
 
-    error = mach_vm_protect(port, (mach_vm_address_t)target, PAGE_SIZE, false, VM_PROT_READ | VM_PROT_WRITE | VM_PROT_COPY);
+    error = mach_vm_protect(port, (mach_vm_address_t)target, PAGE_SIZE, false,
+                            VM_PROT_READ | VM_PROT_WRITE | VM_PROT_COPY);
     if (error != err_none) {
         DETOUR_BREAK();
         goto fail;