* select.c
* - Implements the select() system call (and supporting code)
*/
-#define DEBUG 0
+#define DEBUG 1
#include <acess.h>
#include "vfs.h"
#include "vfs_int.h"
struct sVFS_SelectThread
{
- //! \brief Marks the thread as actively using this select
- int IsActive;
//! \brief Semaphore to atomically put the listener to sleep
tSemaphore SleepHandle; // TODO: Allow timeouts (by setting an alarm?)
};
// === PROTOTYPES ===
- int VFS_Select(int MaxHandle, fd_set *ReadHandles, fd_set *WriteHandles, fd_set *ErrHandles, tTime *Timeout, int IsKernel);
- int VFS_MarkFull(tVFS_Node *Node, BOOL IsBufferFull);
- int VFS_MarkAvaliable(tVFS_Node *Node, BOOL IsDataAvaliable);
- int VFS_MarkError(tVFS_Node *Node, BOOL IsErrorState);
- int VFS_int_Select_Register(tVFS_SelectThread *Thread, int MaxHandle, fd_set *Handles, int Type, BOOL IsKernel);
- int VFS_int_Select_Deregister(tVFS_SelectThread *Thread, int MaxHandle, fd_set *Handles, int Type, BOOL IsKernel);
+// int VFS_SelectNode(tVFS_Node *Node, enum eVFS_SelectTypes Type, tTime *Timeout);
+// int VFS_Select(int MaxHandle, fd_set *ReadHandles, fd_set *WriteHandles, fd_set *ErrHandles, tTime *Timeout, BOOL IsKernel);
+// int VFS_MarkFull(tVFS_Node *Node, BOOL IsBufferFull);
+// int VFS_MarkAvaliable(tVFS_Node *Node, BOOL IsDataAvaliable);
+// int VFS_MarkError(tVFS_Node *Node, BOOL IsErrorState);
+ int VFS_int_Select_GetType(enum eVFS_SelectTypes Type, tVFS_Node *Node, tVFS_SelectList ***List, int **Flag, int *WantedFlag, int *MaxAllowed);
+ int VFS_int_Select_Register(tVFS_SelectThread *Thread, int MaxHandle, fd_set *Handles, enum eVFS_SelectTypes Type, BOOL IsKernel);
+ int VFS_int_Select_Deregister(tVFS_SelectThread *Thread, int MaxHandle, fd_set *Handles, enum eVFS_SelectTypes Type, BOOL IsKernel);
int VFS_int_Select_AddThread(tVFS_SelectList *List, tVFS_SelectThread *Thread, int MaxAllowed);
void VFS_int_Select_RemThread(tVFS_SelectList *List, tVFS_SelectThread *Thread);
+void VFS_int_Select_SignalAll(tVFS_SelectList *List);
// === GLOBALS ===
// === FUNCTIONS ===
-int VFS_Select(int MaxHandle, fd_set *ReadHandles, fd_set *WriteHandles, fd_set *ErrHandles, tTime *Timeout, int IsKernel)
+int VFS_SelectNode(tVFS_Node *Node, enum eVFS_SelectTypes Type, tTime *Timeout)
+{
+ tVFS_SelectThread thread_info;
+ tVFS_SelectList **list;
+ int *flag, wanted, maxAllowed;
+
+ ENTER("pNode iType pTimeout", Node, Type, Timeout);
+
+ Semaphore_Init(&thread_info.SleepHandle, 0, 0, "VFS_SelectNode()", "");
+
+ if( VFS_int_Select_GetType(Type, Node, &list, &flag, &wanted, &maxAllowed) ) {
+ LEAVE('i', -1);
+ return -1;
+ }
+
+ VFS_int_Select_AddThread(*list, &thread_info, maxAllowed);
+ if( *flag == wanted )
+ {
+ VFS_int_Select_RemThread(*list, &thread_info);
+ LEAVE('i', 1);
+ return 1;
+ }
+
+ if( !Timeout || *Timeout > 0 )
+ {
+ // TODO: Actual timeout
+ Semaphore_Wait(&thread_info.SleepHandle, 0);
+ }
+
+ VFS_int_Select_RemThread(*list, &thread_info);
+
+ LEAVE('i', *flag == wanted);
+ return *flag == wanted;
+}
+
+int VFS_Select(int MaxHandle, fd_set *ReadHandles, fd_set *WriteHandles, fd_set *ErrHandles, tTime *Timeout, BOOL IsKernel)
{
tVFS_SelectThread thread_info;
int ret;
// If there were events waiting, de-register and return
if( ret )
{
- ret = VFS_int_Select_Deregister(&thread_info, MaxHandle, ReadHandles, 0, IsKernel);
- ret += VFS_int_Select_Deregister(&thread_info, MaxHandle, ReadHandles, 1, IsKernel);
- ret += VFS_int_Select_Deregister(&thread_info, MaxHandle, ReadHandles, 2, IsKernel);
+ ret = VFS_int_Select_Deregister(&thread_info, MaxHandle, ReadHandles, 0, IsKernel);
+ ret += VFS_int_Select_Deregister(&thread_info, MaxHandle, WriteHandles, 1, IsKernel);
+ ret += VFS_int_Select_Deregister(&thread_info, MaxHandle, ErrHandles, 2, IsKernel);
return ret;
}
// Fill output (modify *Handles)
// - Also, de-register
- ret = VFS_int_Select_Deregister(&thread_info, MaxHandle, ReadHandles, 0, IsKernel);
- ret += VFS_int_Select_Deregister(&thread_info, MaxHandle, ReadHandles, 1, IsKernel);
- ret += VFS_int_Select_Deregister(&thread_info, MaxHandle, ReadHandles, 2, IsKernel);
+ ret = VFS_int_Select_Deregister(&thread_info, MaxHandle, ReadHandles, 0, IsKernel);
+ ret += VFS_int_Select_Deregister(&thread_info, MaxHandle, WriteHandles, 1, IsKernel);
+ ret += VFS_int_Select_Deregister(&thread_info, MaxHandle, ErrHandles, 2, IsKernel);
return ret;
}
+// Mark a node as having data ready for reading
+int VFS_MarkAvaliable(tVFS_Node *Node, BOOL IsDataAvaliable)
+{
+ Node->DataAvaliable = !!IsDataAvaliable;
+ if( Node->DataAvaliable )
+ VFS_int_Select_SignalAll(Node->ReadThreads);
+ return 0;
+}
+
+// Mark a node as having a full buffer
+int VFS_MarkFull(tVFS_Node *Node, BOOL IsBufferFull)
+{
+ Node->BufferFull = !!IsBufferFull;
+ if( !Node->BufferFull )
+ VFS_int_Select_SignalAll(Node->WriteThreads);
+ return 0;
+}
+
+// Mark a node as errored
+int VFS_MarkError(tVFS_Node *Node, BOOL IsErrorState)
+{
+ Node->ErrorOccurred = !!IsErrorState;
+ if( Node->ErrorOccurred )
+ VFS_int_Select_SignalAll(Node->ErrorThreads);
+ return 0;
+}
+
// --- Internal ---
+int VFS_int_Select_GetType(enum eVFS_SelectTypes Type, tVFS_Node *Node, tVFS_SelectList ***List, int **Flag, int *WantedFlag, int *MaxAllowed)
+{
+ // Get the type of the listen
+ switch(Type)
+ {
+ case 0: // Read
+ if(List) *List = &Node->ReadThreads;
+ if(Flag) *Flag = &Node->DataAvaliable;
+ if(WantedFlag) *WantedFlag = 1;
+ if(MaxAllowed) *MaxAllowed = 1; // Max of 1 for read
+ break;
+ case 1: // Write
+ if(List) *List = &Node->WriteThreads;
+ if(Flag) *Flag = &Node->BufferFull;
+ if(WantedFlag) *WantedFlag = 0;
+ if(MaxAllowed) *MaxAllowed = 1; // Max of 1 for write
+ break;
+ case 2: // Error
+ if(List) *List = &Node->ErrorThreads;
+ if(Flag) *Flag = &Node->ErrorOccurred;
+ if(WantedFlag) *WantedFlag = 1;
+ if(MaxAllowed) *MaxAllowed = -1; // No max for error listeners
+ break;
+ default:
+ Log_Error("VFS", "VFS_int_Select_GetType: BUG CHECK, Unknown Type %i", Type);
+ return 1;
+ }
+ return 0;
+}
+
/**
* \return Number of files with an action
*/
-int VFS_int_Select_Register(tVFS_SelectThread *Thread, int MaxHandle, fd_set *Handles, int Type, BOOL IsKernel)
+int VFS_int_Select_Register(tVFS_SelectThread *Thread, int MaxHandle, fd_set *Handles, enum eVFS_SelectTypes Type, BOOL IsKernel)
{
int i, numFlagged = 0;
tVFS_SelectList **list;
}
// Get the type of the listen
- switch(Type)
- {
- case 0: // Read
- list = &handle->Node->ReadThreads;
- flag = &handle->Node->DataAvaliable;
- wantedFlagValue = 1;
- maxAllowed = 1; // Max of 1 for read
- break;
- case 1: // Write
- list = &handle->Node->WriteThreads;
- flag = &handle->Node->BufferFull;
- wantedFlagValue = 0;
- maxAllowed = 1; // Max of 1 for write
- break;
- case 2: // Error
- list = &handle->Node->ErrorThreads;
- flag = &handle->Node->ErrorOccurred;
- wantedFlagValue = 1;
- maxAllowed = -1; // No max for error listeners
- break;
- default:
- Log_Error("VFS", "VFS_int_Select_Deregister: BUG CHECK, Unknown Type %i", Type);
+ if( VFS_int_Select_GetType(Type, handle->Node, &list, &flag, &wantedFlagValue, &maxAllowed) )
return 0;
- }
// Alloc if needed
if( !*list ) {
/**
* \return Number of files with an action
*/
-int VFS_int_Select_Deregister(tVFS_SelectThread *Thread, int MaxHandle, fd_set *Handles, int Type, BOOL IsKernel)
+int VFS_int_Select_Deregister(tVFS_SelectThread *Thread, int MaxHandle, fd_set *Handles, enum eVFS_SelectTypes Type, BOOL IsKernel)
{
int i, numFlagged = 0;
tVFS_SelectList **list;
}
// Get the type of the listen
- switch(Type)
- {
- case 0: // Read
- list = &handle->Node->ReadThreads;
- flag = &handle->Node->DataAvaliable;
- wantedFlagValue = 1;
- break;
- case 1: // Write
- list = &handle->Node->WriteThreads;
- flag = &handle->Node->BufferFull;
- wantedFlagValue = 0;
- break;
- case 2: // Error
- list = &handle->Node->ErrorThreads;
- flag = &handle->Node->ErrorOccurred;
- wantedFlagValue = 1;
- break;
- default:
- Log_Error("VFS", "VFS_int_Select_Deregister: BUG CHECK, Unknown Type %i", Type);
+
+ // Get the type of the listen
+ if( VFS_int_Select_GetType(Type, handle->Node, &list, &flag, &wantedFlagValue, NULL) )
return 0;
- }
// Remove
VFS_int_Select_RemThread(*list, Thread );
} while(block);
// Not on list, is this an error?
+
+ Mutex_Release(&List->Lock);
}
+/**
+ * \brief Signal all threads on a list
+ */
+void VFS_int_Select_SignalAll(tVFS_SelectList *List)
+{
+ int i;
+ tVFS_SelectListEnt *block, *prev;
+
+ // Lock to avoid concurrency issues
+ Mutex_Acquire(&List->Lock);
+
+ block = &List->FirstEnt;
+
+ // Look for the thread
+ do
+ {
+ for( i = 0; i < NUM_THREADS_PER_ALLOC; i ++ )
+ {
+ if( block->Threads[i] )
+ {
+ Semaphore_Signal( &block->Threads[i]->SleepHandle, 1 );
+ }
+ }
+
+ prev = block;
+ block = block->Next;
+ } while(block);
+
+ Mutex_Release(&List->Lock);
+}
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