feat: unify system status codes

kernel/src/Sched/Consent.cpp

@@ -161,25 +161,25 @@ namespace Sched::Consent {
     }
 
     int Register() {
-        if (!HasCapability(CAP_COMPOSITOR)) return SYS_ERR_PERMISSION;
+        if (!HasCapability(CAP_COMPOSITOR)) return CapabilityDenied;
         int pid = GetCurrentPid();
 
         g_lock.Acquire();
         // OnProcessExit clears a dead agent, so a live one is always current.
         if (g_agentPid >= 0 && g_agentPid != pid) {
             g_lock.Release();
-            return -1;
+            return Busy;
         }
         g_agentPid = pid;
         g_lock.Release();
 
         Kt::KernelLogStream(Kt::INFO, "Consent") << "Agent registered: pid " << (uint64_t)pid;
-        return 0;
+        return Success;
     }
 
     int Next(ConsentRequest* out) {
         int agent = GetCurrentPid();
-        if (agent < 0 || agent != g_agentPid) return SYS_ERR_PERMISSION;
+        if (agent < 0 || agent != g_agentPid) return PermissionDenied;
 
         ConsentRequest local;
         for (;;) {
@@ -226,7 +226,7 @@ namespace Sched::Consent {
 
     int Reply(uint64_t id, int decision) {
         int agent = GetCurrentPid();
-        if (agent < 0 || agent != g_agentPid) return SYS_ERR_PERMISSION;
+        if (agent < 0 || agent != g_agentPid) return PermissionDenied;
 
         Request* request = nullptr;
         int pid = -1;
@@ -253,13 +253,13 @@ namespace Sched::Consent {
         }
         g_lock.Release();
 
-        if (request == nullptr) return -1;
+        if (request == nullptr) return InvalidArgument;
         WakeObjectWaiters(request);
 
         Kt::KernelLogStream(Kt::INFO, "Consent") << "pid " << (uint64_t)pid << " "
             << NameOf(capability) << ": "
             << (granted ? "allowed" : (decision == CONSENT_ALLOW ? "allow refused (no longer valid)" : "denied"));
-        return 0;
+        return Success;
     }
 
     void OnProcessExit(int pid) {