KernelLand/Kernel/messages.c

   1 /*
   2  * Acess2 Kernel
   3  * - By John Hodge (thePowersGang)
   4  *
   5  * messages.c
   6  * - IPC Messages
   7  */
   8 #define DEBUG   0
   9 #include <acess.h>
  10 #include <threads.h>
  11 #include <threads_int.h>
  12 #include <errno.h>
  13 #include <events.h>
  14
  15 // === CODE ===
  16 /**
  17  * \fn int Proc_SendMessage(Uint Dest, int Length, void *Data)
  18  * \brief Send an IPC message
  19  * \param Dest  Destination Thread
  20  * \param Length        Length of the message
  21  * \param Data  Message data
  22  */
  23 int Proc_SendMessage(Uint Dest, int Length, void *Data)
  24 {
  25         tThread *thread;
  26         tMsg    *msg;
  27
  28         ENTER("iDest iLength pData", Dest, Length, Data);
  29
  30         if(Length <= 0 || !Data) {
  31                 errno = -EINVAL;
  32                 LEAVE_RET('i', -1);
  33         }
  34
  35         // TODO: Check message length against global/per-thread maximums
  36         // TODO: Restrict queue length
  37
  38         // Get thread
  39         thread = Threads_GetThread( Dest );
  40         if(!thread)     LEAVE_RET('i', -1);
  41         LOG("Destination %p(%i %s)", thread, thread->TID, thread->ThreadName);
  42
  43         // Get Spinlock
  44         SHORTLOCK( &thread->IsLocked );
  45
  46         // Check if thread is still alive
  47         if(thread->Status == THREAD_STAT_DEAD) {
  48                 SHORTREL( &thread->IsLocked );
  49                 LEAVE_RET('i', -1);
  50         }
  51
  52         // Create message
  53         msg = malloc( sizeof(tMsg)+Length );
  54         msg->Next = NULL;
  55         msg->Source = Proc_GetCurThread()->TID;
  56         msg->Length = Length;
  57         memcpy(msg->Data, Data, Length);
  58
  59         // If there are already messages
  60         if(thread->LastMessage) {
  61                 thread->LastMessage->Next = msg;
  62                 thread->LastMessage = msg;
  63         } else {
  64                 thread->Messages = msg;
  65                 thread->LastMessage = msg;
  66         }
  67
  68         SHORTREL(&thread->IsLocked);
  69
  70         // Wake the thread
  71         LOG("Waking %p (%i %s)", thread, thread->TID, thread->ThreadName);
  72         Threads_PostEvent( thread, THREAD_EVENT_IPCMSG );
  73
  74         LEAVE_RET('i', 0);
  75 }
  76
  77 /**
  78  * \fn int Proc_GetMessage(Uint *Source, void *Buffer)
  79  * \brief Gets a message
  80  * \param Source        Where to put the source TID
  81  * \param BufSize       Size of \a Buffer, only this many bytes will be copied
  82  * \param Buffer        Buffer to place the message data (set to NULL to just get message length)
  83  * \return Message length
  84  */
  85 int Proc_GetMessage(Uint *Source, Uint BufSize, void *Buffer)
  86 {
  87          int    ret;
  88         void    *tmp;
  89         tThread *cur = Proc_GetCurThread();
  90
  91         ENTER("pSource pBuffer", Source, Buffer);
  92
  93         // Check if queue has any items
  94         if(!cur->Messages) {
  95                 LEAVE('i', 0);
  96                 return 0;
  97         }
  98
  99         SHORTLOCK( &cur->IsLocked );
 100
 101         if(Source) {
 102                 *Source = cur->Messages->Source;
 103                 LOG("*Source = %i", *Source);
 104         }
 105
 106         // Get message length
 107         if( !Buffer ) {
 108                 ret = cur->Messages->Length;
 109                 SHORTREL( &cur->IsLocked );
 110                 LEAVE('i', ret);
 111                 return ret;
 112         }
 113
 114         // Get message
 115         if(Buffer != GETMSG_IGNORE)
 116         {
 117                 if( !CheckMem( Buffer, BufSize ) )
 118                 {
 119                         LOG("Invalid buffer");
 120                         errno = -EINVAL;
 121                         SHORTREL( &cur->IsLocked );
 122                         LEAVE('i', -1);
 123                         return -1;
 124                 }
 125                 if( BufSize < cur->Messages->Length )
 126                         Log_Notice("Threads", "Buffer of 0x%x passed, but 0x%x long message, truncated",
 127                                 BufSize, cur->Messages->Length);
 128                 else if( BufSize < cur->Messages->Length )
 129                         BufSize = cur->Messages->Length;
 130                 else
 131                         ;       // equal
 132                 LOG("Copied to buffer");
 133                 memcpy(Buffer, cur->Messages->Data, BufSize);
 134         }
 135         ret = cur->Messages->Length;
 136
 137         // Remove from list
 138         tmp = cur->Messages;
 139         cur->Messages = cur->Messages->Next;
 140         // - Removed last message? Clear the end-of-list pointer
 141         if(cur->Messages == NULL)       cur->LastMessage = NULL;
 142         //  > Otherwise, re-mark the IPCMSG event flag
 143         else    cur->EventState |= THREAD_EVENT_IPCMSG;
 144
 145         SHORTREL( &cur->IsLocked );
 146
 147         free(tmp);      // Free outside of lock
 148
 149         LEAVE('i', ret);
 150         return ret;
 151 }