Allowed CVARs to be set in unsafe context

CVAR values set in unsafe context are not written to user configuration file
This does not affect mod's CVARs

https://forum.zdoom.org/viewtopic.php?t=59484

src/c_cvars.cpp

@@ -60,6 +60,7 @@ struct FLatchedValue
 	FBaseCVar *Variable;
 	UCVarValue Value;
 	ECVarType Type;
+	bool UnsafeContext;
 };
 
 static TArray<FLatchedValue> LatchedValues;
@@ -71,11 +72,6 @@ FBaseCVar *CVars = NULL;
 
 int cvar_defflags;
 
-FBaseCVar::FBaseCVar (const FBaseCVar &var)
-{
-	I_FatalError ("Use of cvar copy constructor");
-}
-
 FBaseCVar::FBaseCVar (const char *var_name, uint32_t flags, void (*callback)(FBaseCVar &))
 {
 	FBaseCVar *var;
@@ -148,7 +144,12 @@ void FBaseCVar::ForceSet (UCVarValue value, ECVarType type, bool nouserinfosend)
 	if (m_UseCallback)
 		Callback ();
 
-	Flags &= ~CVAR_ISDEFAULT;
+	if ((Flags & CVAR_ARCHIVE) && !(Flags & CVAR_UNSAFECONTEXT))
+	{
+		SafeValue = GetGenericRep(CVAR_String).String;
+	}
+
+	Flags &= ~(CVAR_ISDEFAULT | CVAR_UNSAFECONTEXT);
 }
 
 void FBaseCVar::SetGenericRep (UCVarValue value, ECVarType type)
@@ -167,13 +168,17 @@ void FBaseCVar::SetGenericRep (UCVarValue value, ECVarType type)
 			latch.Value = value;
 		else
 			latch.Value.String = copystring(value.String);
+		latch.UnsafeContext = !!(Flags & CVAR_UNSAFECONTEXT);
 		LatchedValues.Push (latch);
+
+		Flags &= ~CVAR_UNSAFECONTEXT;
 	}
 	else if ((Flags & CVAR_SERVERINFO) && gamestate != GS_STARTUP && !demoplayback)
 	{
 		if (netgame && !players[consoleplayer].settings_controller)
 		{
 			Printf ("Only setting controllers can change %s\n", Name);
+			Flags &= ~CVAR_UNSAFECONTEXT;
 			return;
 		}
 		D_SendServerInfoChange (this, value, type);
@@ -1134,6 +1139,14 @@ DEFINE_ACTION_FUNCTION(_CVar, ResetToDefault)
 	return 0;
 }
 
+void FBaseCVar::MarkUnsafe()
+{
+	if (!(Flags & CVAR_MOD) && UnsafeExecutionContext)
+	{
+		Flags |= CVAR_UNSAFECONTEXT;
+	}
+}
+
 //
 // Flag cvar implementation
 //
@@ -1644,6 +1657,8 @@ void UnlatchCVars (void)
 	{
 		uint32_t oldflags = var.Variable->Flags;
 		var.Variable->Flags &= ~(CVAR_LATCH | CVAR_SERVERINFO);
+		if (var.UnsafeContext)
+			var.Variable->Flags |= CVAR_UNSAFECONTEXT;
 		var.Variable->SetGenericRep (var.Value, var.Type);
 		if (var.Type == CVAR_String)
 			delete[] var.Value.String;
@@ -1697,9 +1712,7 @@ void C_ArchiveCVars (FConfigFile *f, uint32_t filter)
 			(CVAR_GLOBALCONFIG|CVAR_ARCHIVE|CVAR_MOD|CVAR_AUTO|CVAR_USERINFO|CVAR_SERVERINFO|CVAR_NOSAVE))
 			== filter)
 		{
-			UCVarValue val;
-			val = cvar->GetGenericRep (CVAR_String);
-			f->SetValueForKey (cvar->GetName (), val.String);
+			f->SetValueForKey(cvar->GetName(), cvar->SafeValue);
 		}
 		cvar = cvar->m_Next;
 	}
@@ -1707,16 +1720,6 @@ void C_ArchiveCVars (FConfigFile *f, uint32_t filter)
 
 EXTERN_CVAR(Bool, sv_cheats);
 
-static bool IsUnsafe(const FBaseCVar *const var)
-{
-	const bool unsafe = UnsafeExecutionContext && !(var->GetFlags() & CVAR_MOD);
-	if (unsafe)
-	{
-		Printf(TEXTCOLOR_RED "Cannot set console variable" TEXTCOLOR_GOLD " %s " TEXTCOLOR_RED "from unsafe command\n", var->GetName());
-	}
-	return unsafe;
-}
-
 void FBaseCVar::CmdSet (const char *newval)
 {
 	if ((GetFlags() & CVAR_CHEAT) && !sv_cheats)
@@ -1724,10 +1727,8 @@ void FBaseCVar::CmdSet (const char *newval)
 		Printf("sv_cheats must be true to set this console variable.\n");
 		return;
 	}
-	else if (IsUnsafe(this))
-	{
-		return;
-	}
+
+	MarkUnsafe();
 
 	UCVarValue val;
 
@@ -1814,10 +1815,7 @@ CCMD (toggle)
 	{
 		if ( (var = FindCVar (argv[1], &prev)) )
 		{
-			if (IsUnsafe(var))
-			{
-				return;
-			}
+			var->MarkUnsafe();
 
 			val = var->GetGenericRep (CVAR_Bool);
 			val.Bool = !val.Bool;

src/c_cvars.h

@@ -64,6 +64,7 @@ enum
 	CVAR_MOD			= 8192,	// cvar was defined by a mod
 	CVAR_IGNORE			= 16384,// do not send cvar across the network/inaccesible from ACS (dummy mod cvar)
 	CVAR_CHEAT			= 32768,// can be set only when sv_cheats is enabled
+	CVAR_UNSAFECONTEXT	= 65536,// cvar value came from unsafe context
 };
 
 union UCVarValue
@@ -110,6 +111,7 @@ public:
 	void SetGenericRep (UCVarValue value, ECVarType type);
 	void ResetToDefault ();
 	void SetArchiveBit () { Flags |= CVAR_ARCHIVE; }
+	void MarkUnsafe();
 
 	virtual ECVarType GetRealType () const = 0;
 
@@ -132,7 +134,6 @@ public:
 	static void ListVars (const char *filter, bool plain);
 
 protected:
-	FBaseCVar () {}
 	virtual void DoSet (UCVarValue value, ECVarType type) = 0;
 
 	static bool ToBool (UCVarValue value, ECVarType type);
@@ -147,10 +148,11 @@ protected:
 	static UCVarValue FromGUID (const GUID &value, ECVarType type);
 
 	char *Name;
+	FString SafeValue;
 	uint32_t Flags;
 
 private:
-	FBaseCVar (const FBaseCVar &var);
+	FBaseCVar (const FBaseCVar &var) = delete;
 	FBaseCVar (const char *name, uint32_t flags);
 
 	void (*m_Callback)(FBaseCVar &);