msdos/devices.c

   1 /*
   2  * DOS devices
   3  *
   4  * Copyright 1999 Ove Kåven
   5  */
   6
   7 #include <stdlib.h>
   8 #include <string.h>
   9 #include "wine/winbase16.h"
  10 #include "msdos.h"
  11 #include "miscemu.h"
  12 #include "dosexe.h"
  13 #include "callback.h"
  14 #include "debugtools.h"
  15
  16 #include "pshpack1.h"
  17
  18 typedef struct {
  19   BYTE ljmp1;
  20   RMCBPROC strategy;
  21   BYTE ljmp2;
  22   RMCBPROC interrupt;
  23 } WINEDEV_THUNK;
  24
  25 typedef struct {
  26   BYTE size; /* length of header + data */
  27   BYTE unit; /* unit (block devices only) */
  28   BYTE command;
  29   WORD status;
  30   BYTE reserved[8];
  31 } REQUEST_HEADER;
  32
  33 typedef struct {
  34   REQUEST_HEADER hdr;
  35   BYTE media; /* media descriptor from BPB */
  36   SEGPTR buffer;
  37   WORD count; /* byte/sector count */
  38   WORD sector; /* starting sector (block devices) */
  39   DWORD volume; /* volume ID (block devices) */
  40 } REQ_IO;
  41
  42 typedef struct {
  43   REQUEST_HEADER hdr;
  44   BYTE data;
  45 } REQ_SAFEINPUT;
  46
  47 #include "poppack.h"
  48
  49 #define CON_BUFFER 128
  50
  51 enum strategy { SYSTEM_STRATEGY_NUL, SYSTEM_STRATEGY_CON, NB_SYSTEM_STRATEGIES };
  52
  53 static void *strategy_data[NB_SYSTEM_STRATEGIES];
  54
  55 #define NONEXT ((DWORD)-1)
  56
  57 #define ATTR_STDIN     0x0001
  58 #define ATTR_STDOUT    0x0002
  59 #define ATTR_NUL       0x0004
  60 #define ATTR_CLOCK     0x0008
  61 #define ATTR_FASTCON   0x0010
  62 #define ATTR_RAW       0x0020
  63 #define ATTR_NOTEOF    0x0040
  64 #define ATTR_DEVICE    0x0080
  65 #define ATTR_REMOVABLE 0x0800
  66 #define ATTR_NONIBM    0x2000 /* block devices */
  67 #define ATTR_UNTILBUSY 0x2000 /* char devices */
  68 #define ATTR_IOCTL     0x4000
  69 #define ATTR_CHAR      0x8000
  70
  71 #define CMD_INIT       0
  72 #define CMD_MEDIACHECK 1 /* block devices */
  73 #define CMD_BUILDBPB   2 /* block devices */
  74 #define CMD_INIOCTL    3
  75 #define CMD_INPUT      4 /* read data */
  76 #define CMD_SAFEINPUT  5 /* "non-destructive input no wait", char devices */
  77 #define CMD_INSTATUS   6 /* char devices */
  78 #define CMD_INFLUSH    7 /* char devices */
  79 #define CMD_OUTPUT     8 /* write data */
  80 #define CMD_SAFEOUTPUT 9 /* write data with verify */
  81 #define CMD_OUTSTATUS 10 /* char devices */
  82 #define CMD_OUTFLUSH  11 /* char devices */
  83 #define CMD_OUTIOCTL  12
  84 #define CMD_DEVOPEN   13
  85 #define CMD_DEVCLOSE  14
  86 #define CMD_REMOVABLE 15 /* block devices */
  87 #define CMD_UNTILBUSY 16 /* output until busy */
  88
  89 #define STAT_MASK  0x00FF
  90 #define STAT_DONE  0x0100
  91 #define STAT_BUSY  0x0200
  92 #define STAT_ERROR 0x8000
  93
  94 #define LJMP 0xea
  95
  96
  97 /* prototypes */
  98 static void WINAPI nul_strategy(CONTEXT86*ctx);
  99 static void WINAPI nul_interrupt(CONTEXT86*ctx);
 100 static void WINAPI con_strategy(CONTEXT86*ctx);
 101 static void WINAPI con_interrupt(CONTEXT86*ctx);
 102
 103 /* devices */
 104 typedef struct
 105 {
 106     char name[8];
 107     WORD attr;
 108     RMCBPROC strategy;
 109     RMCBPROC interrupt;
 110
 111 } WINEDEV;
 112
 113 static WINEDEV devs[] =
 114 {
 115   { "NUL     ",
 116     ATTR_CHAR|ATTR_NUL|ATTR_DEVICE,
 117     nul_strategy, nul_interrupt },
 118
 119   { "CON     ",
 120     ATTR_CHAR|ATTR_STDIN|ATTR_STDOUT|ATTR_FASTCON|ATTR_NOTEOF|ATTR_DEVICE,
 121     con_strategy, con_interrupt }
 122 };
 123
 124 #define NR_DEVS (sizeof(devs)/sizeof(WINEDEV))
 125
 126 /* DOS data segment */
 127 typedef struct
 128 {
 129     DOS_LISTOFLISTS    lol;
 130     DOS_DEVICE_HEADER  dev[NR_DEVS-1];
 131     WINEDEV_THUNK      thunk[NR_DEVS];
 132     REQ_IO             req;
 133     BYTE               buffer[CON_BUFFER];
 134
 135 } DOS_DATASEG;
 136
 137 #define DOS_DATASEG_OFF(xxx) FIELD_OFFSET(DOS_DATASEG, xxx)
 138
 139 DWORD DOS_LOLSeg;
 140
 141
 142 /* the device implementations */
 143 static void do_lret(CONTEXT86*ctx)
 144 {
 145   WORD *stack = CTX_SEG_OFF_TO_LIN(ctx, ctx->SegSs, ctx->Esp);
 146
 147   ctx->Eip   = *(stack++);
 148   ctx->SegCs = *(stack++);
 149   ctx->Esp  += 2*sizeof(WORD);
 150 }
 151
 152 static void do_strategy(CONTEXT86*ctx, int id, int extra)
 153 {
 154   REQUEST_HEADER *hdr = CTX_SEG_OFF_TO_LIN(ctx, ctx->SegEs, ctx->Ebx);
 155   void **hdr_ptr = strategy_data[id];
 156
 157   if (!hdr_ptr) {
 158     hdr_ptr = calloc(1,sizeof(void *)+extra);
 159     strategy_data[id] = hdr_ptr;
 160   }
 161   *hdr_ptr = hdr;
 162   do_lret(ctx);
 163 }
 164
 165 static REQUEST_HEADER * get_hdr(int id, void**extra)
 166 {
 167   void **hdr_ptr = strategy_data[id];
 168   if (extra)
 169     *extra = hdr_ptr ? (void*)(hdr_ptr+1) : (void *)NULL;
 170   return hdr_ptr ? *hdr_ptr : (void *)NULL;
 171 }
 172
 173 static void WINAPI nul_strategy(CONTEXT86*ctx)
 174 {
 175   do_strategy(ctx, SYSTEM_STRATEGY_NUL, 0);
 176 }
 177
 178 static void WINAPI nul_interrupt(CONTEXT86*ctx)
 179 {
 180   REQUEST_HEADER *hdr = get_hdr(SYSTEM_STRATEGY_NUL, NULL);
 181   /* eat everything and recycle nothing */
 182   switch (hdr->command) {
 183   case CMD_INPUT:
 184     ((REQ_IO*)hdr)->count = 0;
 185     hdr->status = STAT_DONE;
 186     break;
 187   case CMD_SAFEINPUT:
 188     hdr->status = STAT_DONE|STAT_BUSY;
 189     break;
 190   default:
 191     hdr->status = STAT_DONE;
 192   }
 193   do_lret(ctx);
 194 }
 195
 196 static void WINAPI con_strategy(CONTEXT86*ctx)
 197 {
 198   do_strategy(ctx, SYSTEM_STRATEGY_CON, sizeof(int));
 199 }
 200
 201 static void WINAPI con_interrupt(CONTEXT86*ctx)
 202 {
 203   int *scan;
 204   REQUEST_HEADER *hdr = get_hdr(SYSTEM_STRATEGY_CON,(void **)&scan);
 205   BIOSDATA *bios = DOSMEM_BiosData();
 206   WORD CurOfs = bios->NextKbdCharPtr;
 207   DOS_LISTOFLISTS *lol = DOSMEM_LOL();
 208   DOS_DATASEG *dataseg = (DOS_DATASEG *)lol;
 209   BYTE *linebuffer = dataseg->buffer;
 210   BYTE *curbuffer = (lol->offs_unread_CON) ?
 211     (((BYTE*)dataseg) + lol->offs_unread_CON) : (BYTE*)NULL;
 212   DOS_DEVICE_HEADER *con = dataseg->dev;
 213
 214   switch (hdr->command) {
 215   case CMD_INPUT:
 216     {
 217       REQ_IO *io = (REQ_IO *)hdr;
 218       WORD count = io->count, len = 0;
 219       BYTE *buffer = CTX_SEG_OFF_TO_LIN(ctx,
 220                                         SELECTOROF(io->buffer),
 221                                         (DWORD)OFFSETOF(io->buffer));
 222
 223       hdr->status = STAT_BUSY;
 224       /* first, check whether we already have data in line buffer */
 225       if (curbuffer) {
 226         /* yep, copy as much as we can */
 227         BYTE data = 0;
 228         while ((len<count) && (data != '\r')) {
 229           data = *curbuffer++;
 230           buffer[len++] = data;
 231         }
 232         if (data == '\r') {
 233           /* line buffer emptied */
 234           lol->offs_unread_CON = 0;
 235           curbuffer = NULL;
 236           /* if we're not in raw mode, call it a day*/
 237           if (!(con->attr & ATTR_RAW)) {
 238             hdr->status = STAT_DONE;
 239             io->count = len;
 240             break;
 241           }
 242         } else {
 243           /* still some data left */
 244           lol->offs_unread_CON = curbuffer - (BYTE*)lol;
 245           /* but buffer was filled, we're done */
 246           hdr->status = STAT_DONE;
 247           io->count = len;
 248           break;
 249         }
 250       }
 251
 252       /* if we're in raw mode, we just need to fill the buffer */
 253       if (con->attr & ATTR_RAW) {
 254         while (len<count) {
 255           WORD data;
 256
 257           /* do we have a waiting scancode? */
 258           if (*scan) {
 259             /* yes, store scancode in buffer */
 260             buffer[len++] = *scan;
 261             *scan = 0;
 262             if (len==count) break;
 263           }
 264
 265           /* check for new keyboard input */
 266           while (CurOfs == bios->FirstKbdCharPtr) {
 267             /* no input available yet, so wait... */
 268             Dosvm.Wait( -1, 0 );
 269           }
 270           /* read from keyboard queue (call int16?) */
 271           data = ((WORD*)bios)[CurOfs];
 272           CurOfs += 2;
 273           if (CurOfs >= bios->KbdBufferEnd) CurOfs = bios->KbdBufferStart;
 274           bios->NextKbdCharPtr = CurOfs;
 275           /* if it's an extended key, save scancode */
 276           if (LOBYTE(data) == 0) *scan = HIBYTE(data);
 277           /* store ASCII char in buffer */
 278           buffer[len++] = LOBYTE(data);
 279         }
 280       } else {
 281         /* we're not in raw mode, so we need to do line input... */
 282         while (TRUE) {
 283           WORD data;
 284           /* check for new keyboard input */
 285           while (CurOfs == bios->FirstKbdCharPtr) {
 286             /* no input available yet, so wait... */
 287             Dosvm.Wait( -1, 0 );
 288           }
 289           /* read from keyboard queue (call int16?) */
 290           data = ((WORD*)bios)[CurOfs];
 291           CurOfs += 2;
 292           if (CurOfs >= bios->KbdBufferEnd) CurOfs = bios->KbdBufferStart;
 293           bios->NextKbdCharPtr = CurOfs;
 294
 295           if (LOBYTE(data) == '\r') {
 296             /* it's the return key, we're done */
 297             linebuffer[len++] = LOBYTE(data);
 298             break;
 299           }
 300           else if (LOBYTE(data) >= ' ') {
 301             /* a character */
 302             if ((len+1)<CON_BUFFER) {
 303               linebuffer[len] = LOBYTE(data);
 304               WriteFile(GetStdHandle(STD_OUTPUT_HANDLE), &linebuffer[len++], 1, NULL, NULL);
 305             }
 306             /* else beep, but I don't like noise */
 307           }
 308           else switch (LOBYTE(data)) {
 309           case '\b':
 310             if (len>0) {
 311               len--;
 312               WriteFile(GetStdHandle(STD_OUTPUT_HANDLE), "\b \b", 3, NULL, NULL);
 313             }
 314             break;
 315           }
 316         }
 317         if (len > count) {
 318           /* save rest of line for later */
 319           lol->offs_unread_CON = linebuffer - (BYTE*)lol + count;
 320           len = count;
 321         }
 322         memcpy(buffer, linebuffer, len);
 323       }
 324       hdr->status = STAT_DONE;
 325       io->count = len;
 326     }
 327     break;
 328   case CMD_SAFEINPUT:
 329     if (curbuffer) {
 330       /* some line input waiting */
 331       hdr->status = STAT_DONE;
 332       ((REQ_SAFEINPUT*)hdr)->data = *curbuffer;
 333     }
 334     else if (con->attr & ATTR_RAW) {
 335       if (CurOfs == bios->FirstKbdCharPtr) {
 336         /* no input */
 337         hdr->status = STAT_DONE|STAT_BUSY;
 338       } else {
 339         /* some keyboard input waiting */
 340         hdr->status = STAT_DONE;
 341         ((REQ_SAFEINPUT*)hdr)->data = ((BYTE*)bios)[CurOfs];
 342       }
 343     } else {
 344       /* no line input */
 345       hdr->status = STAT_DONE|STAT_BUSY;
 346     }
 347     break;
 348   case CMD_INSTATUS:
 349     if (curbuffer) {
 350       /* we have data */
 351       hdr->status = STAT_DONE;
 352     }
 353     else if (con->attr & ATTR_RAW) {
 354       if (CurOfs == bios->FirstKbdCharPtr) {
 355         /* no input */
 356         hdr->status = STAT_DONE|STAT_BUSY;
 357       } else {
 358         /* some keyboard input waiting */
 359         hdr->status = STAT_DONE;
 360       }
 361     } else {
 362       /* no line input */
 363       hdr->status = STAT_DONE|STAT_BUSY;
 364     }
 365
 366     break;
 367   case CMD_INFLUSH:
 368     /* flush line and keyboard queue */
 369     lol->offs_unread_CON = 0;
 370     bios->NextKbdCharPtr = bios->FirstKbdCharPtr;
 371     break;
 372   case CMD_OUTPUT:
 373   case CMD_SAFEOUTPUT:
 374     {
 375       REQ_IO *io = (REQ_IO *)hdr;
 376       BYTE *buffer = CTX_SEG_OFF_TO_LIN(ctx,
 377                                         SELECTOROF(io->buffer),
 378                                         (DWORD)OFFSETOF(io->buffer));
 379       DWORD result = 0;
 380       WriteFile(GetStdHandle(STD_OUTPUT_HANDLE), buffer, io->count, &result, NULL);
 381       io->count = result;
 382       hdr->status = STAT_DONE;
 383     }
 384     break;
 385   default:
 386     hdr->status = STAT_DONE;
 387   }
 388   do_lret(ctx);
 389 }
 390
 391 static void InitListOfLists(DOS_LISTOFLISTS *DOS_LOL)
 392 {
 393 /*
 394 Output of DOS 6.22:
 395
 396 0133:0020                    6A 13-33 01 CC 00 33 01 59 00         j.3...3.Y.
 397 0133:0030  70 00 00 00 72 02 00 02-6D 00 33 01 00 00 2E 05   p...r...m.3.....
 398 0133:0040  00 00 FC 04 00 00 03 08-92 21 11 E0 04 80 C6 0D   .........!......
 399 0133:0050  CC 0D 4E 55 4C 20 20 20-20 20 00 00 00 00 00 00   ..NUL     ......
 400 0133:0060  00 4B BA C1 06 14 00 00-00 03 01 00 04 70 CE FF   .K...........p..
 401 0133:0070  FF 00 00 00 00 00 00 00-00 01 00 00 0D 05 00 00   ................
 402 0133:0080  00 FF FF 00 00 00 00 FE-00 00 F8 03 FF 9F 70 02   ..............p.
 403 0133:0090  D0 44 C8 FD D4 44 C8 FD-D4 44 C8 FD D0 44 C8 FD   .D...D...D...D..
 404 0133:00A0  D0 44 C8 FD D0 44                                 .D...D
 405 */
 406   DOS_LOL->CX_Int21_5e01                = 0x0;
 407   DOS_LOL->LRU_count_FCB_cache  = 0x0;
 408   DOS_LOL->LRU_count_FCB_open           = 0x0;
 409   DOS_LOL->OEM_func_handler             = -1; /* not available */
 410   DOS_LOL->INT21_offset         = 0x0;
 411   DOS_LOL->sharing_retry_count  = 3;
 412   DOS_LOL->sharing_retry_delay  = 1;
 413   DOS_LOL->ptr_disk_buf         = 0x0;
 414   DOS_LOL->offs_unread_CON              = 0x0;
 415   DOS_LOL->seg_first_MCB                = 0x0;
 416   DOS_LOL->ptr_first_DPB                = 0x0;
 417   DOS_LOL->ptr_first_SysFileTable       = 0x0;
 418   DOS_LOL->ptr_clock_dev_hdr            = 0x0;
 419   DOS_LOL->ptr_CON_dev_hdr              = 0x0;
 420   DOS_LOL->max_byte_per_sec             = 512;
 421   DOS_LOL->ptr_disk_buf_info            = 0x0;
 422   DOS_LOL->ptr_array_CDS                = 0x0;
 423   DOS_LOL->ptr_sys_FCB          = 0x0;
 424   DOS_LOL->nr_protect_FCB               = 0x0;
 425   DOS_LOL->nr_block_dev         = 0x0;
 426   DOS_LOL->nr_avail_drive_letters       = 26; /* A - Z */
 427   DOS_LOL->nr_drives_JOINed             = 0x0;
 428   DOS_LOL->ptr_spec_prg_names           = 0x0;
 429   DOS_LOL->ptr_SETVER_prg_list  = 0x0; /* no SETVER list */
 430   DOS_LOL->DOS_HIGH_A20_func_offs       = 0x0;
 431   DOS_LOL->PSP_last_exec                = 0x0;
 432   DOS_LOL->BUFFERS_val          = 99; /* maximum: 99 */
 433   DOS_LOL->BUFFERS_nr_lookahead = 8; /* maximum: 8 */
 434   DOS_LOL->boot_drive                   = 3; /* C: */
 435   DOS_LOL->flag_DWORD_moves             = 0x01; /* i386+ */
 436   DOS_LOL->size_extended_mem            = 0xf000; /* very high value */
 437 }
 438
 439 void DOSDEV_InstallDOSDevices(void)
 440 {
 441   DOS_DATASEG *dataseg;
 442   UINT16 seg;
 443   unsigned int n;
 444
 445   /* allocate DOS data segment or something */
 446   DOS_LOLSeg = GlobalDOSAlloc16(sizeof(DOS_DATASEG));
 447   seg = HIWORD(DOS_LOLSeg);
 448   dataseg = MapSL( MAKESEGPTR(LOWORD(DOS_LOLSeg), 0) );
 449
 450   /* initialize the magnificent List Of Lists */
 451   InitListOfLists(&dataseg->lol);
 452
 453   /* Set up first device (NUL) */
 454   dataseg->lol.NUL_dev.next_dev  = MAKESEGPTR(seg, DOS_DATASEG_OFF(dev[0]));
 455   dataseg->lol.NUL_dev.attr      = devs[0].attr;
 456   dataseg->lol.NUL_dev.strategy  = DOS_DATASEG_OFF(thunk[0].ljmp1);
 457   dataseg->lol.NUL_dev.interrupt = DOS_DATASEG_OFF(thunk[0].ljmp2);
 458   memcpy(dataseg->lol.NUL_dev.name, devs[0].name, 8);
 459
 460   /* Set up the remaining devices */
 461   for (n = 1; n < NR_DEVS; n++)
 462   {
 463     dataseg->dev[n-1].next_dev  = (n+1) == NR_DEVS ? NONEXT :
 464                                   MAKESEGPTR(seg, DOS_DATASEG_OFF(dev[n]));
 465     dataseg->dev[n-1].attr      = devs[n].attr;
 466     dataseg->dev[n-1].strategy  = DOS_DATASEG_OFF(thunk[n].ljmp1);
 467     dataseg->dev[n-1].interrupt = DOS_DATASEG_OFF(thunk[n].ljmp2);
 468     memcpy(dataseg->dev[n-1].name, devs[n].name, 8);
 469   }
 470
 471   /* Set up thunks */
 472   for (n = 0; n < NR_DEVS; n++)
 473   {
 474     dataseg->thunk[n].ljmp1     = LJMP;
 475     dataseg->thunk[n].strategy  = (RMCBPROC)DPMI_AllocInternalRMCB(devs[n].strategy);
 476     dataseg->thunk[n].ljmp2     = LJMP;
 477     dataseg->thunk[n].interrupt = (RMCBPROC)DPMI_AllocInternalRMCB(devs[n].interrupt);
 478   }
 479
 480   /* CON is device 1 */
 481   dataseg->lol.ptr_CON_dev_hdr = MAKESEGPTR(seg, DOS_DATASEG_OFF(dev[0]));
 482 }
 483
 484 DWORD DOSDEV_Console(void)
 485 {
 486   return DOSMEM_LOL()->ptr_CON_dev_hdr;
 487 }
 488
 489 DWORD DOSDEV_FindCharDevice(char*name)
 490 {
 491   SEGPTR cur_ptr = MAKESEGPTR(HIWORD(DOS_LOLSeg), FIELD_OFFSET(DOS_LISTOFLISTS,NUL_dev));
 492   DOS_DEVICE_HEADER *cur = DOSMEM_MapRealToLinear(cur_ptr);
 493   char dname[8];
 494   int cnt;
 495
 496   /* get first 8 characters */
 497   strncpy(dname,name,8);
 498   /* if less than 8 characters, pad with spaces */
 499   for (cnt=0; cnt<8; cnt++)
 500     if (!dname[cnt]) dname[cnt]=' ';
 501
 502   /* search for char devices with the right name */
 503   while (cur &&
 504          ((!(cur->attr & ATTR_CHAR)) ||
 505           memcmp(cur->name,dname,8))) {
 506     cur_ptr = cur->next_dev;
 507     if (cur_ptr == NONEXT) cur=NULL;
 508     else cur = DOSMEM_MapRealToLinear(cur_ptr);
 509   }
 510   return cur_ptr;
 511 }
 512
 513 static void DOSDEV_DoReq(void*req, DWORD dev)
 514 {
 515   REQUEST_HEADER *hdr = (REQUEST_HEADER *)req;
 516   DOS_DEVICE_HEADER *dhdr;
 517   CONTEXT86 ctx;
 518   char *phdr;
 519
 520   dhdr = DOSMEM_MapRealToLinear(dev);
 521   phdr = ((char*)DOSMEM_LOL()) + DOS_DATASEG_OFF(req);
 522
 523   /* copy request to request scratch area */
 524   memcpy(phdr, req, hdr->size);
 525
 526   /* prepare to call device driver */
 527   memset(&ctx, 0, sizeof(ctx));
 528
 529   /* ES:BX points to request for strategy routine */
 530   ctx.SegEs = HIWORD(DOS_LOLSeg);
 531   ctx.Ebx   = DOS_DATASEG_OFF(req);
 532
 533   /* call strategy routine */
 534   ctx.SegCs = SELECTOROF(dev);
 535   ctx.Eip   = dhdr->strategy;
 536   DPMI_CallRMProc(&ctx, 0, 0, 0);
 537
 538   /* call interrupt routine */
 539   ctx.SegCs = SELECTOROF(dev);
 540   ctx.Eip   = dhdr->interrupt;
 541   DPMI_CallRMProc(&ctx, 0, 0, 0);
 542
 543   /* completed, copy request back */
 544   memcpy(req, phdr, hdr->size);
 545
 546   if (hdr->status & STAT_ERROR) {
 547     switch (hdr->status & STAT_MASK) {
 548     case 0x0F: /* invalid disk change */
 549       /* this error seems to fit the bill */
 550       SetLastError(ER_NotSameDevice);
 551       break;
 552     default:
 553       SetLastError((hdr->status & STAT_MASK) + 0x13);
 554       break;
 555     }
 556   }
 557 }
 558
 559 static int DOSDEV_IO(unsigned cmd, DWORD dev, DWORD buf, int buflen)
 560 {
 561   REQ_IO req;
 562
 563   req.hdr.size=sizeof(req);
 564   req.hdr.unit=0; /* not dealing with block devices yet */
 565   req.hdr.command=cmd;
 566   req.hdr.status=STAT_BUSY;
 567   req.media=0; /* not dealing with block devices yet */
 568   req.buffer=buf;
 569   req.count=buflen;
 570   req.sector=0; /* block devices */
 571   req.volume=0; /* block devices */
 572
 573   DOSDEV_DoReq(&req, dev);
 574
 575   return req.count;
 576 }
 577
 578 int DOSDEV_Peek(DWORD dev, BYTE*data)
 579 {
 580   REQ_SAFEINPUT req;
 581
 582   req.hdr.size=sizeof(req);
 583   req.hdr.unit=0; /* not dealing with block devices yet */
 584   req.hdr.command=CMD_SAFEINPUT;
 585   req.hdr.status=STAT_BUSY;
 586   req.data=0;
 587
 588   DOSDEV_DoReq(&req, dev);
 589
 590   if (req.hdr.status & STAT_BUSY) return 0;
 591
 592   *data = req.data;
 593   return 1;
 594 }
 595
 596 int DOSDEV_Read(DWORD dev, DWORD buf, int buflen)
 597 {
 598   return DOSDEV_IO(CMD_INPUT, dev, buf, buflen);
 599 }
 600
 601 int DOSDEV_Write(DWORD dev, DWORD buf, int buflen, int verify)
 602 {
 603   return DOSDEV_IO(verify?CMD_SAFEOUTPUT:CMD_OUTPUT, dev, buf, buflen);
 604 }
 605
 606 int DOSDEV_IoctlRead(DWORD dev, DWORD buf, int buflen)
 607 {
 608   return DOSDEV_IO(CMD_INIOCTL, dev, buf, buflen);
 609 }
 610
 611 int DOSDEV_IoctlWrite(DWORD dev, DWORD buf, int buflen)
 612 {
 613   return DOSDEV_IO(CMD_OUTIOCTL, dev, buf, buflen);
 614 }