+++ /dev/null
-/*
- * Acess2 VFS
- * - By thePowersGang (John Hodge)
- *
- * select.c
- * - Implements the select() system call (and supporting code)
- */
-#define DEBUG 1
-#include <acess.h>
-#include "vfs.h"
-#include "vfs_int.h"
-#include "vfs_ext.h"
-#include <semaphore.h>
-
-// === CONSTANTS ===
-#define NUM_THREADS_PER_ALLOC 4
-
-// === TYPES ===
-typedef struct sVFS_SelectThread tVFS_SelectThread;
-typedef struct sVFS_SelectListEnt tVFS_SelectListEnt;
-
-// === STRUCTURES ===
-struct sVFS_SelectListEnt
-{
- tVFS_SelectListEnt *Next;
- tVFS_SelectThread *Threads[NUM_THREADS_PER_ALLOC];
-};
-
-struct sVFS_SelectList
-{
- tMutex Lock;
- tVFS_SelectListEnt FirstEnt;
-};
-
-struct sVFS_SelectThread
-{
- //! \brief Semaphore to atomically put the listener to sleep
- tSemaphore SleepHandle; // TODO: Allow timeouts (by setting an alarm?)
-};
-
-// === PROTOTYPES ===
-// 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_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;
-
- Semaphore_Init(&thread_info.SleepHandle, 0, 0, "VFS_Select()", "");
-
- // Notes: The idea is to make sure we onlt enter wait (on the semaphore)
- // if we are going to be woken up (either by an event at a later time,
- // or by an event that happened while or before we were registering).
- // Hence, register must happen _before_ we check the state flag
- // (See VFS_int_Select_Register), that way either we pick up the flag,
- // or the semaphore is incremeneted (or both, but never none)
-
- // Register with nodes
- ret = VFS_int_Select_Register(&thread_info, MaxHandle, ReadHandles, 0, IsKernel);
- ret += VFS_int_Select_Register(&thread_info, MaxHandle, WriteHandles, 1, IsKernel);
- ret += VFS_int_Select_Register(&thread_info, MaxHandle, ErrHandles, 2, IsKernel);
-
- // 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, WriteHandles, 1, IsKernel);
- ret += VFS_int_Select_Deregister(&thread_info, MaxHandle, ErrHandles, 2, IsKernel);
- return ret;
- }
-
- // TODO: Implement timeout
-
- // Wait (only if there is no timeout, or it is greater than zero
- if( !Timeout || *Timeout > 0 )
- {
- ret = Semaphore_Wait(&thread_info.SleepHandle, 0);
- }
-
- // 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, 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, enum eVFS_SelectTypes Type, BOOL IsKernel)
-{
- int i, numFlagged = 0;
- tVFS_SelectList **list;
- int *flag, wantedFlagValue;
- int maxAllowed;
-
- if( !Handles ) return 0;
-
- for( i = 0; i < MaxHandle; i ++ )
- {
- tVFS_Handle *handle;
-
- // Is the descriptor set
- if( !FD_ISSET(i, Handles) ) continue;
-
- handle = VFS_GetHandle( i | (IsKernel?VFS_KERNEL_FLAG:0) );
- // Is the handle valid?
- if( !handle || !handle->Node )
- {
- if( Type == 2 ) { // Bad FD counts as an error
- numFlagged ++;
- }
- else {
- FD_CLR(i, Handles);
- }
- continue;
- }
-
- // Get the type of the listen
- if( VFS_int_Select_GetType(Type, handle->Node, &list, &flag, &wantedFlagValue, &maxAllowed) )
- return 0;
-
- // Alloc if needed
- if( !*list ) {
- *list = calloc(1, sizeof(tVFS_SelectList));
- }
-
- // Register
- if( VFS_int_Select_AddThread(*list, Thread, maxAllowed ) )
- {
- // Oops, error (or just no space)
- FD_CLR(i, Handles);
- }
-
- // Check for the flag
- if( !!*flag == !!wantedFlagValue )
- numFlagged ++;
- }
-
- return numFlagged;
-}
-/**
- * \return Number of files with an action
- */
-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;
- int *flag, wantedFlagValue;
-
- if( !Handles ) return 0;
-
- for( i = 0; i < MaxHandle; i ++ )
- {
- tVFS_Handle *handle;
-
- // Is the descriptor set
- if( !FD_ISSET(i, Handles) ) continue;
-
- handle = VFS_GetHandle( i | (IsKernel?VFS_KERNEL_FLAG:0) );
- // Is the handle valid?
- if( !handle || !handle->Node )
- {
- if( Type == 2 ) { // Bad FD counts as an error
- numFlagged ++;
- }
- else {
- FD_CLR(i, Handles);
- }
- continue;
- }
-
- // Get the type of the listen
-
- // 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 );
-
- // Check for the flag
- if( !!*flag == !!wantedFlagValue ) {
- numFlagged ++;
- }
- else {
- FD_CLR(i, Handles);
- }
- }
-
- return numFlagged;
-}
-
-/**
- * \return Boolean failure
- */
-int VFS_int_Select_AddThread(tVFS_SelectList *List, tVFS_SelectThread *Thread, int MaxAllowed)
-{
- int i, count = 0;
- tVFS_SelectListEnt *block, *prev;
-
- // Lock to avoid concurrency issues
- Mutex_Acquire(&List->Lock);
-
- block = &List->FirstEnt;
-
- // Look for free space
- do
- {
- for( i = 0; i < NUM_THREADS_PER_ALLOC; i ++ )
- {
- if( block->Threads[i] == NULL )
- {
- block->Threads[i] = Thread;
- Mutex_Release(&List->Lock);
- return 0;
- }
- count ++;
- if( MaxAllowed && count >= MaxAllowed ) {
- return 1;
- }
- }
-
- prev = block;
- block = block->Next;
- } while(block);
-
- // Create new block
- block = malloc( sizeof(tVFS_SelectListEnt) );
- if( !block ) {
- Log_Warning("VFS", "VFS_int_Select_AddThread: malloc() failed");
- Mutex_Release(&List->Lock);
- return -1;
- }
- block->Next = NULL;
- block->Threads[0] = Thread;
- for( i = 1; i < NUM_THREADS_PER_ALLOC; i ++ )
- {
- block->Threads[i] = NULL;
- }
-
- // Add to list
- prev->Next = block;
-
- // Release
- Mutex_Release(&List->Lock);
-
- return 0;
-}
-
-void VFS_int_Select_RemThread(tVFS_SelectList *List, tVFS_SelectThread *Thread)
-{
- 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] == Thread )
- {
- block->Threads[i] = NULL;
-
- // Check if this block is empty
- if( block != &List->FirstEnt )
- {
- for( i = 0; i < NUM_THREADS_PER_ALLOC; i ++ )
- if( block->Threads[i] )
- break;
- // If empty, free it
- if( i == NUM_THREADS_PER_ALLOC ) {
- prev->Next = block->Next;
- free(block);
- }
- //TODO: If not empty, check if it can be merged downwards
- }
-
- Mutex_Release(&List->Lock);
- return ;
- }
- }
-
- prev = block;
- block = block->Next;
- } 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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