From e48f1c339ff22b3b1951f3dfd05b54b4ba5b075a Mon Sep 17 00:00:00 2001
From: SciresM <Sciresm@gmail.com>
Date: Wed, 27 Jan 2021 14:20:41 -0800
Subject: [PATCH] add hosversionIsAtmosphere (#525)

---
 nx/include/switch/runtime/hosversion.h | 3 +++
 nx/source/runtime/hosversion.c         | 7 ++++++-
 nx/source/services/ro.c                | 2 +-
 nx/source/services/sm.c                | 2 +-
 4 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/nx/include/switch/runtime/hosversion.h b/nx/include/switch/runtime/hosversion.h
index d03c642e..3e794309 100644
--- a/nx/include/switch/runtime/hosversion.h
+++ b/nx/include/switch/runtime/hosversion.h
@@ -25,6 +25,9 @@ u32 hosversionGet(void);
 /// Sets or overrides the current HOS version. This function is normally called automatically by libnx on startup with the version info obtained with \ref setsysGetFirmwareVersion.
 void hosversionSet(u32 version);
 
+/// Returns whether the current HOS version is augmented by running the Atmosphère custom firmware.
+bool hosversionIsAtmosphere(void);
+
 /// Returns true if the current HOS version is equal to or above the specified major/minor/micro version.
 static inline bool hosversionAtLeast(u8 major, u8 minor, u8 micro) {
     return hosversionGet() >= MAKEHOSVERSION(major,minor,micro);
diff --git a/nx/source/runtime/hosversion.c b/nx/source/runtime/hosversion.c
index 5bffb725..f6b5915c 100644
--- a/nx/source/runtime/hosversion.c
+++ b/nx/source/runtime/hosversion.c
@@ -4,10 +4,15 @@ static u32 g_hosVersion;
 
 u32 hosversionGet(void)
 {
-    return __atomic_load_n(&g_hosVersion, __ATOMIC_SEQ_CST);
+    return __atomic_load_n(&g_hosVersion, __ATOMIC_SEQ_CST) & ~(BIT(31));
 }
 
 void hosversionSet(u32 version)
 {
     __atomic_store_n(&g_hosVersion, version, __ATOMIC_SEQ_CST);
 }
+
+bool hosversionIsAtmosphere(void)
+{
+    return __atomic_load_n(&g_hosVersion, __ATOMIC_SEQ_CST) & (BIT(31));
+}
diff --git a/nx/source/services/ro.c b/nx/source/services/ro.c
index cfa815e9..d8de3e52 100644
--- a/nx/source/services/ro.c
+++ b/nx/source/services/ro.c
@@ -49,7 +49,7 @@ Service* ro1GetServiceSession(void) {
 }
 
 Result _roDmntInitialize(void) {
-    if (hosversionBefore(3,0,0)) return MAKERESULT(Module_Libnx, LibnxError_IncompatSysVer);
+    if (!hosversionIsAtmosphere() && hosversionBefore(3,0,0)) return MAKERESULT(Module_Libnx, LibnxError_IncompatSysVer);
     return smGetService(&g_dmntSrv, "ro:dmnt");
 }
 
diff --git a/nx/source/services/sm.c b/nx/source/services/sm.c
index b0ca8788..aba4fa6c 100644
--- a/nx/source/services/sm.c
+++ b/nx/source/services/sm.c
@@ -112,6 +112,6 @@ Result smUnregisterService(SmServiceName name) {
 }
 
 Result smDetachClient(void) {
-    if (hosversionBefore(11,0,0)) return MAKERESULT(Module_Libnx, LibnxError_IncompatSysVer);
+    if (!hosversionIsAtmosphere() && hosversionBefore(11,0,0)) return MAKERESULT(Module_Libnx, LibnxError_IncompatSysVer);
     return _smCmdInPid(4);
 }