detour_detach + some setters

include/mach_detours.h

@@ -26,4 +26,9 @@ mach_error_t detour_attach(detour_func_t* inout_pointer, detour_func_t 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);
 mach_error_t detour_detach(detour_func_t* inout_pointer, detour_func_t detour);
 
+bool detour_set_ignore_too_small(bool value);
+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);
+
 #endif // MACH_DETOURS_H

src/mach_detours.c

@@ -9,7 +9,7 @@
 #define DETOURS_ARM64
 #define DETOURS_64BIT
 #else
-#error Unsupported architecture (arm64)
+#error Unsupported architecture (supported: arm64)
 #endif
 
 #include "detours_internal.h"
@@ -640,6 +640,9 @@ mach_error_t detour_manage_thread(thread_t thread)
     return err_none;
 }
 
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+// Attach/Detach
+
 mach_error_t detour_attach(detour_func_t* inout_pointer, detour_func_t detour)
 {
     return detour_attach_ex(inout_pointer, detour, nullptr, nullptr, nullptr);
@@ -898,3 +901,133 @@ mach_error_t detour_attach_ex(detour_func_t* inout_pointer, detour_func_t detour
 
     return err_none;
 }
+
+mach_error_t detour_detach(detour_func_t* inout_pointer, detour_func_t detour)
+{
+    if (s_transaction_thread != mach_thread_self()) {
+        return detour_err_wrong_thread;
+    }
+
+    // If any of the pending operations failed, then we don't need to do this.
+    if (s_pending_error != err_none) {
+        return s_pending_error;
+    }
+
+    if (!detour) {
+        return KERN_INVALID_ARGUMENT;
+    }
+    if (!inout_pointer) {
+        return KERN_INVALID_ARGUMENT;
+    }
+    if (!(*inout_pointer)) {
+        s_pending_error = KERN_INVALID_ARGUMENT;
+        s_pending_error_pointer = inout_pointer;
+        DETOUR_BREAK();
+        return s_pending_error;
+    }
+
+    mach_error_t error = err_none;
+
+    detour_operation* op = calloc(1, sizeof(detour_operation));
+    if (!op) {
+        error = KERN_RESOURCE_SHORTAGE;
+      fail:
+        s_pending_error = error;
+        DETOUR_BREAK();
+      stop:
+        free(op);
+        // ReSharper disable once CppDFAUnusedValue
+        op = nullptr;
+        s_pending_error_pointer = inout_pointer;
+        return error;
+    }
+
+    detour_trampoline* trampoline = (detour_trampoline*)internal_detour_skip_jmp(*inout_pointer);
+    detour = internal_detour_skip_jmp(detour);
+
+    // Verify that Trampoline is in place.
+    const int32_t restore_code_size = trampoline->restore_code_size;
+    uint8_t* target = trampoline->ptr_remain - restore_code_size;
+    if (restore_code_size == 0 || restore_code_size > sizeof(trampoline->code)) {
+        error = KERN_FAILURE;
+        if (s_ignore_too_small) {
+            goto stop;
+        } else {
+            DETOUR_BREAK();
+            goto fail;
+        }
+    }
+
+    if (trampoline->ptr_detour != detour) {
+        error = KERN_FAILURE;
+        if (s_ignore_too_small) {
+            goto stop;
+        } else {
+            DETOUR_BREAK();
+            goto fail;
+        }
+    }
+
+    const mach_port_t port = mach_task_self();
+
+    vm_region_submap_short_info_data_64_t region_info;
+    {
+        mach_vm_address_t region_addr = (mach_vm_address_t)target;
+        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);
+        if (error != err_none) {
+            DETOUR_BREAK();
+            goto fail;
+        }
+    }
+    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);
+    if (error != err_none) {
+        DETOUR_BREAK();
+        goto fail;
+    }
+
+    op->kind = detour_operation_kind_detach;
+    op->pointer = (uint8_t**)inout_pointer;
+    op->trampoline = trampoline;
+    op->target = target;
+    op->perm = old_perm;
+    op->next = s_pending_operations_head;
+    s_pending_operations_head = op;
+
+    return ERR_SUCCESS;
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+// API Setters
+
+bool detour_set_ignore_too_small(const bool value)
+{
+    const bool previous = s_ignore_too_small;
+    s_ignore_too_small = value;
+    return previous;
+}
+
+bool detour_set_retain_regions(const bool value)
+{
+    const bool previous = s_retain_regions;
+    s_retain_regions = value;
+    return previous;
+}
+
+void* detour_set_system_region_lower_bound(void* value)
+{
+    void* previous = s_system_region_lower_bound;
+    s_system_region_lower_bound = value;
+    return previous;
+}
+
+void* detour_set_system_region_upper_bound(void* value)
+{
+    void* previous = s_system_region_upper_bound;
+    s_system_region_upper_bound = value;
+    return previous;
+}