kernel/vfs/vfs.asm

   1 ;----------------------------------------------------------;
   2 ; BOS kernel                Christoffer Bubach, 2012-2015. ;
   3 ;----------------------------------------------------------;
   4 ;                                                          ;
   5 ;        VFS handling all devices and filesystems.         ;
   6 ;                                                          ;
   7 ;----------------------------------------------------------;
   8
   9
  10     ;---------------------------------------------;
  11     ;   VFS main structure                        ;
  12     ;---------------------------------------------;
  13     struc VFS
  14     {
  15         .number:                times 255      db 0   ; 00=FD, 0x10=HD, 0x60=CD, 0x80=VD, 90=RD, B0=ND
  16         .storage:
  17             times 255 * sizeof.VFS_storage     db 0   ; storage driver structure
  18         .filesystem:
  19             times 255 * sizeof.VFS_filesystem  db 0   ; filesystem driver structure
  20         .mounted                               db 0   ; 1/0 switch if mounted
  21         .current_path:          times 255      db 0   ; drive opened path (increase max path size?)
  22     }
  23
  24     virtual at 0                                      ; could use "at esi" instead
  25         VFS VFS
  26         sizeof.VFS = $-$$
  27     end virtual
  28
  29     ;---------------------------------------------;
  30     ;   VFS storage driver structure              ;
  31     ;---------------------------------------------;
  32     struc VFS_storage
  33     {
  34         .data_pointer         dd  0                   ; internal driver data
  35         .init                 dd  0                   ; pointer to init
  36         .deinit               dd  0                   ; remove driver
  37         .read                 dd  0                   ; read device
  38         .write                dd  0                   ; write device
  39         .ioctl                dd  0                   ; handle device specific extras
  40     }
  41
  42     virtual at 0
  43         VFS_storage VFS_storage
  44         sizeof.VFS_storage = $-$$
  45     end virtual
  46
  47     ;---------------------------------------------;
  48     ;   VFS filesystem structure                  ;
  49     ;---------------------------------------------;
  50     struc VFS_filesystem
  51     {
  52         .data_pointer         dd  0                   ; internal driver data
  53         .FSname               db  0,0,0,0,0           ; 5 char filesystem name
  54         .init                 dd  0                   ; pointer to init
  55         .deinit               dd  0                   ; remove driver
  56         .format               dd  0                   ; format drive
  57         .mount                dd  0                   ; mount drive
  58         .unmount              dd  0                   ; unmount drive
  59         .find                 dd  0                   ; find file
  60         .findnext             dd  0                   ; get next match
  61         .open                 dd  0                   ; open file, get handle
  62         .close                dd  0                   ; close file from handle
  63         .attrib               dd  0                   ; get/set attrib. and time
  64         .read                 dd  0                   ; read file from handle
  65         .write                dd  0                   ; write file from handle
  66         .seek                 dd  0                   ; seek from handle
  67         .rename               dd  0                   ; rename file
  68         .remove               dd  0                   ; remove file/dir
  69         .create               dd  0                   ; create file/dir
  70         .ioctl                dd  0                   ; extra calls if exists
  71     }
  72
  73     virtual at 0
  74         VFS_filesystem VFS_filesystem
  75         sizeof.VFS_filesystem = $-$$
  76     end virtual
  77
  78     ;---------------------------------------------;
  79     ;   VFS structure pointer                     ;
  80     ;---------------------------------------------;
  81     VFS_structure             dd 0
  82
  83
  84 ;--------------------------------------------------------------;
  85 ;   init_vfs  -  detect connected drives                       ;
  86 ;--------------------------------------------------------------;
  87 ;                                                              ;
  88 ;       out:                    cf = set if failed             ;
  89 ;                                                              ;
  90 ;--------------------------------------------------------------;
  91 init_vfs:
  92         push   eax
  93         push   ebx
  94
  95         mov    ebx, sizeof.VFS                        ; allocate structure size
  96         call   allocate_mem
  97         cmp    eax, 0
  98         jne    .ok
  99         stc                                           ; if error, set carry
 100         mov    ebx, 0
 101
 102     .ok:
 103         mov    dword [VFS_structure], ebx
 104
 105         pop    ebx
 106         pop    eax
 107         ret
 108
 109 ;--------------------------------------------------------------;
 110 ;   add_media  -  add media driver                             ;
 111 ;--------------------------------------------------------------;
 112 ;                                                              ;
 113 ;       in:  reg = pointer to VFS drive info                   ;
 114 ;                                                              ;
 115 ;       out: reg = pointer to struct(s) if FAT12 found         ;
 116 ;                                                              ;
 117 ;--------------------------------------------------------------;
 118 add_media:
 119         push   eax
 120         ;...
 121         pop    eax
 122         ret
 123
 124 ;--------------------------------------------------------------;
 125 ;   add_fs  -  add filesystem driver                           ;
 126 ;--------------------------------------------------------------;
 127 ;                                                              ;
 128 ;       in:  reg = pointer to VFS drive info                   ;
 129 ;                                                              ;
 130 ;       out: reg = pointer to struct(s) if FAT12 found         ;
 131 ;                                                              ;
 132 ;--------------------------------------------------------------;
 133 add_fs:
 134         push   eax
 135         ;...
 136         pop    eax
 137         ret
 138
 139 ;--------------------------------------------------------------;
 140 ;   open_file  -  open file, return handle                     ;
 141 ;--------------------------------------------------------------;
 142 ;                                                              ;
 143 ;       in:  reg = ASCIIZ file name and such                   ;
 144 ;                                                              ;
 145 ;       out: reg = dword file handle                           ;
 146 ;                                                              ;
 147 ;--------------------------------------------------------------;
 148 open_file:
 149         push   eax
 150         ; file handles need to be dword, where the high
 151         ; word contains drive number, and the low word
 152         ; is the drive/FS specific handle.  meaning no internal
 153         ; table in VFS, created dynamically with FS info.
 154         ; limits FS to a max of 65535 opened files. most use fewer
 155         ; as default. FAT12 driver has 32.
 156         ; FS reports error if handle is invalid.
 157         pop    eax
 158         ret