Syscalls - Changed SysGetMessage to provide a buffer size

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

diff --git a/KernelLand/Kernel/messages.c b/KernelLand/Kernel/messages.c
index 09c8c14..c991978 100644 (file)
--- a/KernelLand/Kernel/messages.c
+++ b/KernelLand/Kernel/messages.c
@@ -78,10 +78,11 @@ int Proc_SendMessage(Uint Dest, int Length, void *Data)
  * \fn int Proc_GetMessage(Uint *Source, void *Buffer)
  * \brief Gets a message
  * \param Source       Where to put the source TID
+ * \param BufSize      Size of \a Buffer, only this many bytes will be copied
  * \param Buffer       Buffer to place the message data (set to NULL to just get message length)
  * \return Message length
  */
-int Proc_GetMessage(Uint *Source, void *Buffer)
+int Proc_GetMessage(Uint *Source, Uint BufSize, void *Buffer)
 {
         int    ret;
        void    *tmp;
@@ -113,7 +114,7 @@ int Proc_GetMessage(Uint *Source, void *Buffer)
        // Get message
        if(Buffer != GETMSG_IGNORE)
        {
-               if( !CheckMem( Buffer, cur->Messages->Length ) )
+               if( !CheckMem( Buffer, BufSize ) )
                {
                        LOG("Invalid buffer");
                        errno = -EINVAL;
@@ -121,8 +122,15 @@ int Proc_GetMessage(Uint *Source, void *Buffer)
                        LEAVE('i', -1);
                        return -1;
                }
+               if( BufSize < cur->Messages->Length )
+                       Log_Notice("Threads", "Buffer of 0x%x passed, but 0x%x long message, truncated",
+                               BufSize, cur->Messages->Length);
+               else if( BufSize < cur->Messages->Length )
+                       BufSize = cur->Messages->Length;
+               else
+                       ;       // equal
                LOG("Copied to buffer");
-               memcpy(Buffer, cur->Messages->Data, cur->Messages->Length);
+               memcpy(Buffer, cur->Messages->Data, BufSize);
        }
        ret = cur->Messages->Length;