Kernel - Fixed a double-lock in message handling

[tpg/acess2.git] / Kernel / messages.c

diff --git a/Kernel/messages.c b/Kernel/messages.c
index aaedf5c..1391d99 100644 (file)
--- a/Kernel/messages.c
+++ b/Kernel/messages.c
@@ -1,9 +1,14 @@
 /*
- * AcessOS Microkernel Version
+ * Acess2 Kernel
+ * - By John Hodge (thePowersGang)
+ *
  * messages.c
+ * - IPC Messages
  */
+#define DEBUG  0
 #include <acess.h>
-#include <proc.h>
+#include <threads.h>
+#include <threads_int.h>
 #include <errno.h>
 
 // === CODE ===
@@ -20,24 +25,27 @@ int Proc_SendMessage(Uint *Err, Uint Dest, int Length, void *Data)
        tThread *thread;
        tMsg    *msg;
        
-       Log("Proc_SendMessage: (Err=%p, Dest=%i, Length=%i, Data=%p)", Err, Dest, Length, Data);
+       ENTER("pErr iDest iLength pData", Err, Dest, Length, Data);
        
        if(Length <= 0 || !Data) {
                *Err = -EINVAL;
-               return -1;
+               LEAVE_RET('i', -1);
        }
        
        // Get thread
        thread = Threads_GetThread( Dest );
        
        // Error check
-       if(!thread) {   return -1;      }
+       if(!thread)     LEAVE_RET('i', -1);
        
        // Get Spinlock
-       LOCK( &thread->IsLocked );
+       SHORTLOCK( &thread->IsLocked );
        
        // Check if thread is still alive
-       if(thread->Status == THREAD_STAT_DEAD)  return -1;
+       if(thread->Status == THREAD_STAT_DEAD) {
+               SHORTREL( &thread->IsLocked );
+               LEAVE_RET('i', -1);
+       }
        
        // Create message
        msg = malloc( sizeof(tMsg)+Length );
@@ -55,11 +63,12 @@ int Proc_SendMessage(Uint *Err, Uint Dest, int Length, void *Data)
                thread->LastMessage = msg;
        }
        
-       RELEASE(&thread->IsLocked);
+       SHORTREL(&thread->IsLocked);
        
+       LOG("Waking %p (%i %s)", thread, thread->TID, thread->ThreadName);
        Threads_Wake( thread );
        
-       return 0;
+       LEAVE_RET('i', 0);
 }
 
 /**
@@ -72,23 +81,29 @@ int Proc_SendMessage(Uint *Err, Uint Dest, int Length, void *Data)
 int Proc_GetMessage(Uint *Err, Uint *Source, void *Buffer)
 {
         int    ret;
-       void *tmp;
+       void    *tmp;
        tThread *cur = Proc_GetCurThread();
+
+       ENTER("pSource pBuffer", Source, Buffer);
        
        // Check if queue has any items
        if(!cur->Messages) {
+               LEAVE('i', 0);
                return 0;
        }
 
-       LOCK( &cur->IsLocked );
+       SHORTLOCK( &cur->IsLocked );
        
-       if(Source)
+       if(Source) {
                *Source = cur->Messages->Source;
+               LOG("*Source = %i", *Source);
+       }
        
        // Get message length
        if( !Buffer ) {
                ret = cur->Messages->Length;
-               RELEASE( &cur->IsLocked );
+               SHORTREL( &cur->IsLocked );
+               LEAVE('i', ret);
                return ret;
        }
        
@@ -97,20 +112,26 @@ int Proc_GetMessage(Uint *Err, Uint *Source, void *Buffer)
        {
                if( !CheckMem( Buffer, cur->Messages->Length ) )
                {
+                       LOG("Invalid buffer");
                        *Err = -EINVAL;
-                       RELEASE( &cur->IsLocked );
+                       SHORTREL( &cur->IsLocked );
+                       LEAVE('i', -1);
                        return -1;
                }
+               LOG("Copied to buffer");
                memcpy(Buffer, cur->Messages->Data, cur->Messages->Length);
        }
        ret = cur->Messages->Length;
        
        // Remove from list
-       tmp = cur->Messages->Next;
-       free( (void*)cur->Messages );
-       cur->Messages = tmp;
+       tmp = cur->Messages;
+       cur->Messages = cur->Messages->Next;
+       if(cur->Messages == NULL)       cur->LastMessage = NULL;
        
-       RELEASE( &cur->IsLocked );
+       SHORTREL( &cur->IsLocked );
        
+       free(tmp);      // Free outside of lock
+
+       LEAVE('i', ret);
        return ret;
 }