KernelLand/Kernel/drv/zero-one.c

   1 /*
   2  * Acess2 Kernel
   3  * - By John Hodge (thePowersGang)
   4  *
   5  * drv/zero-one.c
   6  * - /Devices/{null,zero,one}
   7  */
   8 #define DEBUG   0
   9 #include <acess.h>
  10 #include <modules.h>
  11 #include <fs_devfs.h>
  12
  13 // === PROTOTYPES ===
  14  int    CoreDevs_Install(char **Arguments);
  15 size_t  CoreDevs_Write(tVFS_Node *Node, off_t Offset, size_t Length, const void *Buffer);
  16 size_t  CoreDevs_Read_Zero(tVFS_Node *Node, off_t Offset, size_t Length, void *Buffer);
  17 size_t  CoreDevs_Read_One (tVFS_Node *Node, off_t Offset, size_t Length, void *Buffer);
  18 size_t  CoreDevs_Read_Null(tVFS_Node *Node, off_t Offset, size_t Length, void *Buffer);
  19
  20 // === GLOBALS ===
  21 MODULE_DEFINE(0, 0x0100, CoreDevs, CoreDevs_Install, NULL, NULL);
  22 tVFS_NodeType   gCoreDevs_NT_Null = {
  23         .TypeName = "CoreDevs-null",
  24         .Read  = CoreDevs_Read_Null,
  25         .Write = CoreDevs_Write
  26 };
  27 tVFS_NodeType   gCoreDevs_NT_Zero = {
  28         .TypeName = "CoreDevs-zero",
  29         .Read  = CoreDevs_Read_Zero,
  30         .Write = CoreDevs_Write
  31 };
  32 tVFS_NodeType   gCoreDevs_NT_One = {
  33         .TypeName = "CoreDevs-one",
  34         .Read  = CoreDevs_Read_One,
  35         .Write = CoreDevs_Write
  36 };
  37 tDevFS_Driver   gCoreDevs_Null = {
  38         NULL, "null",
  39         {
  40         .Size = 0,
  41         .NumACLs = 1,
  42         .ACLs = &gVFS_ACL_EveryoneRW,
  43         .Type = &gCoreDevs_NT_Null
  44         }
  45 };
  46 tDevFS_Driver   gCoreDevs_Zero = {
  47         NULL, "zero",
  48         {
  49         .Size = 0,
  50         .NumACLs = 1,
  51         .ACLs = &gVFS_ACL_EveryoneRW,
  52         .Type = &gCoreDevs_NT_Zero
  53         }
  54 };
  55 tDevFS_Driver   gCoreDevs_One = {
  56         NULL, "one",
  57         {
  58         .Size = 0,
  59         .NumACLs = 1,
  60         .ACLs = &gVFS_ACL_EveryoneRW,
  61         .Type = &gCoreDevs_NT_One
  62         }
  63 };
  64
  65 // === CODE ===
  66 /**
  67  * \brief Installs the CoreDevs driver
  68  */
  69 int CoreDevs_Install(char **Options)
  70 {
  71         DevFS_AddDevice( &gCoreDevs_Null );
  72         DevFS_AddDevice( &gCoreDevs_Zero );
  73         DevFS_AddDevice( &gCoreDevs_One  );
  74         return MODULE_ERR_OK;
  75 }
  76
  77 size_t CoreDevs_Write(tVFS_Node *Node, off_t Offset, size_t Length, const void *Buffer)
  78 {
  79         return Length;  // Ignore
  80 }
  81
  82 size_t CoreDevs_Read_Zero(tVFS_Node *Node, off_t Offset, size_t Length, void *Buffer)
  83 {
  84         memset(Buffer, 0, Length);
  85         return Length;
  86 }
  87
  88 size_t CoreDevs_Read_One (tVFS_Node *Node, off_t Offset, size_t Length, void *Buffer)
  89 {
  90         Uint8   *ptr = Buffer;
  91         size_t  rem;
  92         for( rem = Length; rem --; ptr ++ )
  93                 *ptr = 0xFF;
  94         return Length;
  95 }
  96
  97 size_t CoreDevs_Read_Null(tVFS_Node *Node, off_t Offset, size_t Length, void *Buffer)
  98 {
  99         return 0;
 100 }
 101