int21.c

freedos32的源代码

/* INT 21h handler for the FreeDOS-32 DPMI Driver
 * Copyright (C) 2001-2005  Salvatore ISAJA
 *
 * This file "int21.c" is part of the FreeDOS-32 DPMI Driver (the Program).
 *
 * The Program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * The Program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with the Program; see the file GPL.txt; if not, write to
 * the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/* TODO: We should provide some mechanism for installing new fake
         interrupt handlers (like this INT 21h handler), with the   
         possibility of recalling the old one.
*/

#include <ll/i386/hw-data.h>
#include <ll/i386/string.h>
#include <kernel.h>
#include <filesys.h>
#include <errno.h>
#include <stubinfo.h>
#include <logger.h>
#include <fd32time.h>
#include "rmint.h"

#define DOS_API_INPUT_IS_UTF8 1
#if !DOS_API_INPUT_IS_UTF8
 #include <unicode/unicode.h>
 #include <nls/nls.h>
 struct nls_operations *current_cp;
#endif

#if defined(__GNUC__) && !defined(restrict)
 #define restrict __restrict__
#endif

/* Define the __DEBUG__ symbol in order to activate log output */
//#define __DEBUG__
#ifdef __DEBUG__
 #define LOG_PRINTF(s) fd32_log_printf s
#else
 #define LOG_PRINTF(s)
#endif

#define FAR2ADDR(seg, off) (((DWORD) seg << 4) + (DWORD) off)


/* The current PSP is needed for the pointer to the DTA */
extern struct psp *current_psp;

int use_lfn;


/* Parameter block for the dos_exec call, see INT 21h AH=4Bh */
typedef struct
{
  WORD  Env;
  WORD arg_offs;
  WORD arg_seg;
  DWORD Fcb1;
  DWORD Fcb2;
  DWORD Res1;
  DWORD Res2;
}
__attribute__ ((packed)) ExecParams;
/* DOS return code of the last executed program */
static WORD dos_return_code;


/* Data structure for INT 21 AX=7303h                   */
/* Windows95 - FAT32 - Get extended free space on drive */
typedef struct
{
  WORD  Size;            /* Size of the returned structure (this one)  */
  WORD  Version;         /* Version of this structure (desired/actual) */
  /* The following are *with* adjustment for compression */
  DWORD SecPerClus;      /* Sectors per cluster               */
  DWORD BytesPerSec;     /* Bytes per sector                  */
  DWORD AvailClus;       /* Number of available clusters      */
  DWORD TotalClus;       /* Total number of clusters on drive */
  /* The following are *without* adjustment for compression */
  DWORD RealSecPerClus;  /* Number of sectors per cluster     */
  DWORD RealBytesPerSec; /* Bytes per sector                  */
  DWORD RealAvailClus;   /* Number of available clusters      */
  DWORD RealTotalClus;   /* Total number of clusters on drive */
  BYTE  Reserved[8];
}
__attribute__ ((packed)) ExtDiskFree;


/* DOS error codes (see RBIL table 01680) */
#define DOS_ENOTSUP   0x01 /* function number invalid */
#define DOS_ENOENT    0x02 /* file not found */
#define DOS_ENOTDIR   0x03 /* path not found */
#define DOS_EMFILE    0x04 /* too many open files */
#define DOS_EACCES    0x05 /* access denied */
#define DOS_EBADF     0x06 /* invalid handle */
#define DOS_ENOMEM    0x08 /* insufficient memory */
#define DOS_EMEMBLK   0x09 /* memory block address invalid */
#define DOS_EFTYPE    0x0B /* format invalid */
#define DOS_EDATA     0x0D /* data invalid */
#define DOS_ENOTBLK   0x0F /* invalid drive */
#define DOS_EXDEV     0x11 /* not same device */
#define DOS_ENOMOREF  0x12 /* no more files */
#define DOS_EROFS     0x13 /* disk write-protected */
#define DOS_EUNIT     0x14 /* unknown unit */
#define DOS_ENOMEDIUM 0x15 /* drive not ready */
#define DOS_EIO       0x1F /* general failure */
#define DOS_ENOSPC    0x27 /* insufficient disk space */
#define DOS_EEXIST    0x50 /* file exists */
#define DOS_EUNKNOWN  0x64 /* unknown error */
#define DOS_EBUFSMALL 0x7A /* buffer too small to hold return data */
#define DOS_EINVAL    0xA0 /* bad arguments */
#define DOS_ENOLCK    0xB4 /* lock count has been exceeded */
#define DOS_ENOEXEC   0xC1 /* bad EXE format */

/* Lookup table to convert FD32 errno codes to DOS error codes */
/* TODO: Fine tune the mapping using the DJGPP one as a reference */
static const BYTE errno2dos[] = {
/*   0 */ 0x00,         DOS_EUNKNOWN, DOS_ENOENT,   DOS_EUNKNOWN,
/*   4 */ DOS_EUNKNOWN, DOS_EIO,      DOS_EUNIT,    DOS_EUNKNOWN,
/*   8 */ DOS_ENOEXEC,  DOS_EBADF,    DOS_EUNKNOWN, DOS_EUNKNOWN,
/*  12 */ DOS_ENOMEM,   DOS_EACCES,   DOS_EMEMBLK,  DOS_EUNIT,
/*  16 */ DOS_EUNKNOWN, DOS_EEXIST,   DOS_EXDEV,    DOS_EUNIT,
/*  20 */ DOS_ENOTDIR,  DOS_EACCES,   DOS_EINVAL,   DOS_EMFILE,
/*  24 */ DOS_EMFILE,   DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EACCES,
/*  28 */ DOS_ENOSPC,   DOS_EUNKNOWN, DOS_EROFS,    DOS_EUNKNOWN,
/*  32 */ DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN,
/*  36 */ DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN,
/*  40 */ DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN,
/*  44 */ DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_ENOLCK,   DOS_EUNKNOWN,
/*  48 */ DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN,
/*  52 */ DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_ENOTSUP,  DOS_EUNKNOWN,
/*  56 */ DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN,
/*  60 */ DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN,
/*  64 */ DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN,
/*  68 */ DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN,
/*  72 */ DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN,
/*  76 */ DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EFTYPE,
/*  80 */ DOS_EUNKNOWN, DOS_EBADF,    DOS_EUNKNOWN, DOS_EUNKNOWN,
/*  84 */ DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN,
/*  88 */ DOS_ENOTSUP,  DOS_EMFILE,   DOS_EACCES,   DOS_EBUFSMALL,
/*  92 */ DOS_EACCES,   DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_ENOTSUP,
/*  96 */ DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN,
/* 100 */ DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN,
/* 104 */ DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN,
/* 108 */ DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN,
/* 112 */ DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN,
/* 116 */ DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN,
/* 120 */ DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN,
/* 124 */ DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN,
/* 128 */ DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EUNKNOWN,
/* 132 */ DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_ENOTSUP,  DOS_ENOMEDIUM,
/* 136 */ DOS_EUNKNOWN, DOS_EUNKNOWN, DOS_EDATA
};


/* Converts a FD32 return code (< 0 meaning error)
 * to a DOS return status in the specified register set.
 * - on error: carry flag set, error (positive) in AX
 * - on success: carry flag clear
 */
static void res2dos(int res, union rmregs *r)
{
	LOG_PRINTF(("INT 21h - res=%i\n", res));
	RMREGS_CLEAR_CARRY;
	if (res < 0)
	{
		res = -res;
		RMREGS_SET_CARRY;
		r->x.ax = DOS_EUNKNOWN;
		if (res < sizeof(errno2dos)) r->x.ax = errno2dos[res];
	}
}


/* Converts a DOS open action (see RBIL table 01770) to a libc mode. */
static int parse_open_action(int dos_action)
{
	int action = 0;
	if (dos_action & 0x10) action |= O_CREAT;
	switch (dos_action & ~0x10)
	{
		case 0x00: action |= O_EXCL; break;
		case 0x01: break;
		case 0x02: action |= O_TRUNC; break;
		default: action = -EINVAL;
	}
	return action;
}


/* Converts a path name from DOS API to UTF-8 using no more than "size" bytes.
 * Forward slashes '/' are converted to back slashes '\'.
 * Returns 0 on success, or a negative error.
 */
static int fix_path(char *restrict dest, const char *restrict source, size_t size)
{
	#if DOS_API_INPUT_IS_UTF8
	char c;
	while (*source)
	{
		if (!size) return -ENAMETOOLONG;
		c = *(source++);
		if (c == '/') c = '\\';
		*(dest++) = c;
	}
	#else
	int res = 0;
	wchar_t wc;
	while (*source)
	{
		res = current_cp->mbtowc(&wc, source, NLS_MB_MAX_LEN);
		if (res < 0) return res;
		source += res;
		if (wc == (wchar_t) '/') wc = (wchar_t) '\\';
		res = unicode_wctoutf8(dest, wc, size);
		if (res < 0) return res;
		dest += res;
		size -= res;
		
	}
	#endif
	if (!size) return -ENAMETOOLONG;
	*dest = 0;
	return 0;
}


/* Sub-handler for DOS services "Get/set file's time stamps"
 * INT 21h AH=57h (BX=file handle, AL=action).
 */
static inline void get_and_set_time_stamps(union rmregs *r)
{
	fd32_fs_attr_t a;
	int res;
	a.Size = sizeof(fd32_fs_attr_t);
	switch (r->h.al)
	{
		/* Get last modification date and time */
		case 0x00:
			/* TODO: MS-DOS returns date and time of opening for char devices */
			res = fd32_get_attributes(r->x.bx, &a);
			if (res >= 0)
			{
				r->x.cx = a.MTime;
				r->x.dx = a.MDate;
			}
			break;
		/* Set last modification date and time */
		case 0x01:
			res = fd32_get_attributes(r->x.bx, &a);
			if (res >= 0)
			{
				a.MTime = r->x.cx;
				a.MDate = r->x.dx;
				res = fd32_set_attributes(r->x.bx, &a);
			}
			break;
		/* Get last access date and time */
		case 0x04:
			res = fd32_get_attributes(r->x.bx, &a);
			if (res >= 0)
			{
				r->x.dx = a.ADate;
				r->x.cx = 0x0000; /* FAT has not the last access time */
			}
			break;
		/* Set last access date and time */
		case 0x05:
			if (r->x.cx != 0x0000)
			{
				/* FAT has not the last access time */
				res = -EINVAL;
				break;
			}
			res = fd32_get_attributes(r->x.bx, &a);
			if (res >= 0)
			{
				a.ADate = r->x.dx;
				res = fd32_set_attributes(r->x.bx, &a);
			}
			break;
		/* Get creation date and time */
		case 0x06:
			res = fd32_get_attributes(r->x.bx, &a);
			if (res >= 0)
			{
				r->x.dx = a.CDate;
				r->x.cx = a.CTime;
				r->x.si = a.CHund;
			}
			break;
		/* Set creation date and time */
		case 0x07:
			res = fd32_get_attributes(r->x.bx, &a);
			if (res >= 0)
			{
				a.CDate = r->x.dx;
				a.CTime = r->x.cx;
				a.CHund = r->x.si;
				res = fd32_set_attributes(r->x.bx, &a);
			}
			break;
		/* Invalid subfunctions */
		default:
			r->h.al = 0xFF; /* Yet another convention */
			RMREGS_SET_CARRY;
			return;
	}
	res2dos(res, r);
}


/* Sub-handler for DOS service "Get/set file's attributes"
 * INT 21h AH=43h (DS:DX->ASCIZ file name, AL=action).
 */
static inline void dos_get_and_set_attributes(union rmregs *r)
{
	char fn[FD32_LFNPMAX];
	fd32_fs_attr_t a;
	int fd;
	int res = fix_path(fn, (const char *) FAR2ADDR(r->x.ds, r->x.dx), sizeof(fn));
	if (res < 0)
	{
		res2dos(res, r);
		return;
	}
	fd = fd32_open(fn, O_RDONLY, FD32_ANONE, 0, NULL);
	if (fd < 0) /* It could be a directory... */
		fd = fd32_open(fn, O_RDONLY | O_DIRECTORY, FD32_ANONE, 0, NULL);
	if (fd < 0)
	{
		res2dos(fd, r);
		return;
	}
	a.Size = sizeof(fd32_fs_attr_t);
	switch (r->h.al)
	{
		/* Get file attributes */
		case 0x00:
			LOG_PRINTF(("INT 21h - Getting attributes of \"%s\"\n", fn));
			res = fd32_get_attributes(fd, &a);
			if (res >= 0)
			{
				r->x.cx = a.Attr;
				r->x.ax = r->x.cx; /* DR-DOS 5.0 */
			}
			break;
		/* Set file attributes */
		case 0x01:
			/* FIXME: Should close the file if currently open in sharing-compat
			 *        mode, or generate a sharing violation critical error in
			 *        the file is currently open.
			 * Mah! Would that be true with the new things? Mah...
			 */
			LOG_PRINTF(("INT 21h - Setting attributes of \"%s\" to %04x\n", fn, r->x.cx));
			res = fd32_get_attributes(fd, &a);
			if (res < 0) break;
			/* Volume label and directory attributes cannot be changed.
			 * To change the other attributes bits of a directory the directory
			 * flag must be clear, though it will be set after this call.
			 */
			if ((r->x.cx & (FD32_AVOLID | FD32_ADIR)) || (a.Attr == FD32_AVOLID))
			{
				res = -EACCES;
				break;
			}
			a.Attr = r->x.cx;
			if (a.Attr & FD32_ADIR) a.Attr = r->x.cx | FD32_ADIR;
			res = fd32_set_attributes(fd, &a);
			break;
		/* Invalid subfunctions */
		default:
			fd32_close(fd);
			r->h.al = 0xFF; /* Yet another convention */
			RMREGS_SET_CARRY;
			return;