From 603c3f40ccfa18c918d135031d60f604deac8e48 Mon Sep 17 00:00:00 2001
From: Levente Meszaros <levy@omnetpp.org>
Date: Mon, 25 Mar 2024 09:54:16 +0100
Subject: [PATCH] common: Added Linux OS guards to network and user namespaces.

---
 src/inet/common/NetworkNamespaceContext.cc      | 14 ++++++++++++++
 src/inet/common/UnsharedNamespaceInitializer.cc |  6 ++++++
 2 files changed, 20 insertions(+)

diff --git a/src/inet/common/NetworkNamespaceContext.cc b/src/inet/common/NetworkNamespaceContext.cc
index 4cdab7e08cb..940b0c9d67c 100644
--- a/src/inet/common/NetworkNamespaceContext.cc
+++ b/src/inet/common/NetworkNamespaceContext.cc
@@ -20,6 +20,7 @@ std::map<std::string, int> localNetworkNamespaces; // network namespace which ar
 
 void createNetworkNamespace(const char *name, bool global)
 {
+#ifdef __linux__
     if (global) {
         std::string fullPath = std::string("/var/run/netns/") + name;
         int fd = open(fullPath.c_str(), O_RDONLY | O_CREAT | O_EXCL, 0);
@@ -40,10 +41,14 @@ void createNetworkNamespace(const char *name, bool global)
         // switch back to the original namespace that was used before unshare
         setns(oldFd, 0);
     }
+#else
+    throw cRuntimeError("Network namespaces are only supported on Linux");
+#endif
 }
 
 bool existsNetworkNamespace(const char *name)
 {
+#ifdef __linux__
     auto it = localNetworkNamespaces.find(name);
     if (it != localNetworkNamespaces.end())
         return true;
@@ -56,9 +61,13 @@ bool existsNetworkNamespace(const char *name)
         }
     }
     return false;
+#else
+    throw cRuntimeError("Network namespaces are only supported on Linux");
+#endif
 }
 
 void deleteNetworkNamespace(const char *name) {
+#ifdef __linux__
     auto it = localNetworkNamespaces.find(name);
     if (it != localNetworkNamespaces.end()) {
         auto it = localNetworkNamespaces.find(name);
@@ -72,6 +81,9 @@ void deleteNetworkNamespace(const char *name) {
         if (unlink(path.c_str()) != 0)
             throw cRuntimeError("Cannot unlink file: %s", path.c_str());
     }
+#else
+    throw cRuntimeError("Network namespaces are only supported on Linux");
+#endif
 }
 
 NetworkNamespaceContext::NetworkNamespaceContext(const char *name)
@@ -117,6 +129,8 @@ NetworkNamespaceContext::~NetworkNamespaceContext()
         }
         oldFd = -1;
         newFd = -1;
+#else
+        throw cRuntimeError("Network namespaces are only supported on Linux");
 #endif
     }
 }
diff --git a/src/inet/common/UnsharedNamespaceInitializer.cc b/src/inet/common/UnsharedNamespaceInitializer.cc
index 233eff8ed2c..db557fdaf02 100644
--- a/src/inet/common/UnsharedNamespaceInitializer.cc
+++ b/src/inet/common/UnsharedNamespaceInitializer.cc
@@ -15,7 +15,9 @@ Register_GlobalConfigOption(CFGID_UNSHARE_USER_NAMESPACE, "unshare-user-namespac
 
 UnsharedNamespaceInitializer UnsharedNamespaceInitializer::singleton;
 
+#ifdef __linux__
 EXECUTE_ON_STARTUP(getEnvir()->addLifecycleListener(&UnsharedNamespaceInitializer::singleton));
+#endif
 
 void UnsharedNamespaceInitializer::lifecycleEvent(SimulationLifecycleEventType eventType, cObject *details)
 {
@@ -35,6 +37,7 @@ void UnsharedNamespaceInitializer::lifecycleEvent(SimulationLifecycleEventType e
 
 void UnsharedNamespaceInitializer::unshareUserNamespace()
 {
+#ifdef __linux__
     pid_t originalUid = getuid();
     pid_t originalGid = getgid();
     if (unshare(CLONE_NEWUSER) < 0)
@@ -52,13 +55,16 @@ void UnsharedNamespaceInitializer::unshareUserNamespace()
     // change effective user to root
     if (seteuid(0) < 0)
         throw cRuntimeError("Failed to switch to the root user");
+#endif
 }
 
 void UnsharedNamespaceInitializer::unshareNetworkNamespace()
 {
+#ifdef __linux__
     if (unshare(CLONE_NEWNET) < 0)
         throw cRuntimeError("Failed to unshare network namespace");
     originalNetworkNamespaceFd = open("/proc/self/ns/net", O_RDONLY);
+#endif
 }
 
 void UnsharedNamespaceInitializer::writeMapping(const char* path, const char* mapping)