/*
 *
 * DANG_BEGIN_MODULE
 * REMARK
 *
 * This file contains a simple system for passing information through to
 * DOSEMU from the Linux side. It does not allow dynamic message passing,
 * but it intended to provide useful information for the DOS user.
 *
 * As such, the current set of implemented commands are :
 * GET_USER_ENVVAR and GET_COMMAND
 *
 * These are made available to the DOSEMU by using the DOS_HELPER interrupt
 * (Currently 0xE6) and writing a string into a location passed to this
 * interrupt handler using the registers. In the case of GET_USER_ENVVAR the
 * string also contains the name of the environment variable to interrogate.
 * (The string is overwritten with the reply).
 *
 * /REMARK
 * DANG_END_MODULE
 *
 * DANG_BEGIN_CHANGELOG
 *
 *	$Log$
 *	Revision 1.16  2006/01/28 09:45:34  bartoldeman
 *	Move disclaimer and install prompts from dos_post_boot to banner code,
 *	using BIOS calls.
 *
 *	Revision 1.15  2005/12/31 06:23:11  bartoldeman
 *	Mostly from Clarence: unix.com patches in dosemu-exec-friendly.diff,
 *	so that "dosemu keen1.exe" works again.
 *	But do not use heuristics that split options from commands, by making
 *	quotes of filenames that contain spaces compulsory.
 *
 *	Revision 1.14  2005/12/18 07:58:44  bartoldeman
 *	Put some basic checks into dos_read/dos_write, and memmove_dos2dos to
 *	avoid touching the protected video memory.
 *	Fixes #1379806 (gw stopped to work under X).
 *
 *	Revision 1.13  2005/11/29 18:24:31  stsp
 *
 *	call_msdos() must switch to real mode before calling DOS, if needed.
 *
 *	Revision 1.12  2005/11/29 10:25:04  bartoldeman
 *	Adjust video.c init so that -dumb does not pop up an X window.
 *	Make -dumb quiet until the command is executed if a command is given. So
 *	dosemu -dumb dir
 *	gives a directory listing and nothing else.
 *
 *	Revision 1.11  2005/11/21 18:12:51  stsp
 *
 *	- Map the DOS<-->unix STDOUT/STDERR properly for unix.com.
 *	- Improved the DOS console reading for unix.com
 *
 *	Revision 1.10  2005/11/19 00:54:40  stsp
 *
 *	Make unix.com "keyboard-aware" (FR #1360156). It works like a tty
 *	in a -icanon mode.
 *	system() replaced with execlp() to make it possible to emulate ^C
 *	with SIGINT.
 *	Also reworked the output-grabbing again - it was still skipping an
 *	output sometimes.
 *
 *	Revision 1.9  2005/11/18 21:47:56  stsp
 *
 *	Make unix.com to use DOS/stdout instead of the direct video mem access,
 *	so that the file redirection to work.
 *
 *	Revision 1.8  2005/11/02 04:52:55  stsp
 *
 *	Fix run_unix_command (#1345102)
 *
 *	Revision 1.7  2005/09/30 22:15:59  stsp
 *
 *	Avoid using LOWMEM for the non-const addresses.
 *	This fixes iplay (again), as it read()s directly to the EMS frame.
 *	Also, moved dos_read/write to dos2linux.c to make them globally
 *	available. And removed the __builtin_constant_p() check in LINEAR2UNIX -
 *	gcc might still be able to optimize the const addresses, but falling
 *	back for dosaddr_to_unixaddr() will happen less frequently.
 *
 *	Revision 1.6  2005/09/05 09:47:56  bartoldeman
 *	Moved much of X_change_config to dos2linux.c. Much of it will be shared
 *	with SDL.
 *
 *	Revision 1.5  2005/06/20 17:12:11  stsp
 *
 *	Remove the ancient (unused) ioctl queueing code.
 *
 *	Revision 1.4  2005/05/20 00:26:09  bartoldeman
 *	It's 2005 this year.
 *
 *	Revision 1.3  2005/03/21 17:24:09  stsp
 *
 *	Fixed (and re-enabled) the terminate-after-execute feature (bug #1152829).
 *	Also some minor adjustments/leftovers.
 *
 *	Revision 1.2  2004/01/16 20:50:27  bartoldeman
 *	Happy new year!
 *
 *	Revision 1.1.1.1  2003/06/23 00:02:07  bartoldeman
 *	Initial import (dosemu-1.1.5.2).
 *
 *
 * DANG_END_CHANGELOG
 *
 */



#include <stdio.h>
#include <stdlib.h>
#include <libgen.h>
#include <unistd.h>
#ifdef HAVE_LIBBSD
#include <bsd/unistd.h>
#endif
#include <errno.h>
#include <fcntl.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <signal.h>
#include <string.h>
#include <ctype.h>
#include <stdarg.h>
#include <assert.h>
#include <pthread.h>
#ifdef __GLIBC__
#include <alloca.h>
#endif
#include <semaphore.h>

#include "emu.h"
#include "cpu-emu.h"
#include "int.h"
#include "emudpmi.h"
#include "timers.h"
#include "video.h"
#include "lowmem.h"
#include "coopth.h"
#include "utilities.h"
#include "dos2linux.h"
#include "vgaemu.h"
#include "disks.h"
#include "mapping/mapping.h"
#include "redirect.h"
#include "translate/translate.h"
#include "../../dosext/mfs/lfn.h"
#include "../../dosext/mfs/mfs.h"
#include "mmio_tracing.h"
#include "misc/spscq.h"
#include "fslib/fslib.h"

#define com_stderr      2

#ifndef max
#define max(a,b)       ((a)>(b)? (a):(b))
#endif

#define GET_USER_ENVVAR      0x52
#define EXEC_USER_COMMAND    0x50

static char *misc_dos_options;
int com_errno;

char *misc_e6_options(void)
{
  return misc_dos_options;
}

void misc_e6_store_options(const char *str)
{
  size_t olen = 0;
  size_t slen = strlen(str);
  /* any later arguments are collected as DOS options */
  if (misc_dos_options) {
    olen = strlen(misc_dos_options);
    misc_dos_options = realloc(misc_dos_options, olen + slen + 2);
    misc_dos_options[olen] = ' ';
    strcpy(misc_dos_options + olen + 1, str);
  } else {
    misc_dos_options = malloc(slen + 1);
    strcpy(misc_dos_options, str);
  }
  g_printf ("Storing Options : %s\n", misc_dos_options);
}


static int pty_fd;
static int mfs_idx;
static int cbrk;
static pthread_t reader;
struct rd_args {
    int fd;
    int *done;
    void *queue;
    int crlf;
};

static void *rd_thread(void *arg)
{
    struct rd_args *args = arg;

    while (1) {
        void *ptr;
        unsigned len;
        ssize_t rd;

        ptr = spscq_write_area(args->queue, &len);
        rd = read(args->fd, ptr, len);
        if (rd <= 0)
            break;
        spscq_commit_write(args->queue, rd);
    }
    __atomic_store_n(args->done, 1, __ATOMIC_RELAXED);
    return NULL;
}

static void pty_worker(struct rd_args *args)
{
#define MAX_LEN (1024+1)
    char buf[MAX_LEN];
    int rd, wr;
    int done = 0;
    struct char_set_state kstate;
    struct char_set_state dstate;

    init_charset_state(&kstate, trconfig.keyb_charset);
    init_charset_state(&dstate, trconfig.dos_charset);
    while (1) {
	rd = spscq_read(args->queue, buf, sizeof(buf) - 1);
	if (rd > 0) {
		int rc;
		const char *p = buf;
		buf[rd] = 0;
		while (*p) {
		    t_unicode uni[MAX_LEN];
		    const t_unicode *u = uni;
		    char buf2[MAX_LEN * MB_LEN_MAX];
		    rc = charset_to_unicode_string(&kstate, uni, &p, strlen(p),
			    MAX_LEN);
		    if (rc <= 0)
			break;
		    rc = unicode_to_charset_string(&dstate, buf2, &u, rc,
			    sizeof(buf2));
		    if (rc <= 0)
			break;
		    if (args->crlf) {
			char *buf3 = strdup_crlf(buf2);
			com_doswritecon(buf3, strlen(buf3));
			free(buf3);
		    } else {
			com_doswritecon(buf2, rc);
		    }
		}
		continue;
	}
	if (done)
	    break;
	if ((done = __atomic_load_n(args->done, __ATOMIC_RELAXED)))
	    continue;  // last re-check

	wr = com_dosreadcon(buf, sizeof(buf) - 1);
	if (wr > 0)
	    write(pty_fd, buf, wr);

	if (!rd && !wr)
	    coopth_wait();
    }
    cleanup_charset_state(&kstate);
    cleanup_charset_state(&dstate);
}

void dos2tty_init(void)
{
    char pts[PATH_MAX], *dn;
    int err;

    pty_fd = posix_openpt(O_RDWR);
    if (pty_fd == -1)
    {
        error("openpt() failed %s\n", strerror(errno));
        return;
    }
    unlockpt(pty_fd);
    err = ptsname_r(pty_fd, pts, sizeof(pts));
    if (err) {
        error("ptsname() failed %s\n", strerror(errno));
        return;
    }
    dn = dirname(pts);
    assert(dn && dn[0] != '\0' && dn == pts);
    if (dn[strlen(dn) - 1] != '/')
        strlcat(pts, "/", sizeof(pts));
    mfs_idx = mfs_define_drive(pts);
}

void dos2tty_done(void)
{
    close(pty_fd);
}

static int pts_open(void)
{
    int err, pts_fd;

    err = grantpt(pty_fd);
    if (err) {
	error("grantpt failed: %s\n", strerror(errno));
	return err;
    }
    /* set ctty in child later */
    pts_fd = mfs_open_file(mfs_idx, ptsname(pty_fd), O_RDWR | O_NOCTTY);
    if (pts_fd == -1) {
	error("pts open failed: %s\n", strerror(errno));
	return -1;
    }
    return pts_fd;
}

static void dos2tty_start(struct rd_args *args)
{
    char a;
    int rd;

    cbrk = com_setcbreak(0);
    /* flush pending input first */
    do {
	rd = com_dosreadcon(&a, 1);
    } while (rd > 0);
    /* must run with interrupts enabled to read keypresses */
    assert(!isset_IF());
    set_IF();

    *args->done = 0;
    create_thread(&reader, rd_thread, args, "dosemu: ttyrd");
    pty_worker(args);

    clear_IF();
    com_setcbreak(cbrk);
    pthread_join(reader, NULL);
}

static int do_wait_cmd(pid_t pid)
{
    int status, retval;
    void *queue;
    int pty_done;
    struct rd_args args;

    queue = spscq_init(1024 * 64); // 64K queue
    assert(queue);
    args.fd = pty_fd;
    args.done = &pty_done;
    args.queue = queue;
    dos2tty_start(&args);
    spscq_done(queue);
    while ((retval = waitpid(pid, &status, WNOHANG)) == 0)
	coopth_wait();
    if (retval == -1)
	error("waitpid: %s\n", strerror(errno));
    /* print child exitcode. not perfect */
    g_printf("run_unix_command() (parent): child exit code: %i\n",
            WEXITSTATUS(status));
    return WEXITSTATUS(status);
}

int run_unix_command(int argc, const char **argv, int bg)
{
    const char *path;
    char *p;
    pid_t pid;

    assert(!under_root_login);  // should not happen because earlier checks
    path = findprog(argv[0], getenv("PATH"));
    if (!path) {
	com_printf("unix: %s not found\n", argv[0]);
	return -1;
    }
    /* check if path allowed */
    p = config.unix_exec ? strstr(config.unix_exec, path) : NULL;
    if (p) {
	/* make sure the found string is entire word */
	int l = strlen(path);
	if ((p > config.unix_exec && p[-1] != ' ') ||
		(p[l] != '\0' && p[l] != ' '))
	    p = NULL;
    }
    if (!p) {
	com_printf("unix: execution of %s is not allowed.\n"
		"Add %s to $_unix_exec list.\n",
		argv[0], path);
	error("execution of %s is not allowed.\n"
		"Add %s to $_unix_exec list.\n",
		argv[0], path);
	return -1;
    }

    g_printf("UNIX: run %s, %i args\n", path, argc);
    pid = run_external_command(path, argc, argv, !bg, pts_open);
    if (bg) {
	sigchld_enable_cleanup(pid);
	return 0;
    }
    return do_wait_cmd(pid);
}

static int do_wait_custom(pid_t pid, int fd)
{
    int status, retval;
    int done;
    void *queue;
    struct rd_args args;

    queue = spscq_init(1024 * 64); // 64K queue
    assert(queue);
    args.fd = fd;
    args.done = &done;
    args.queue = queue;
    args.crlf = 1;
    dos2tty_start(&args);
    spscq_done(queue);
    while ((retval = fslib_waitpid(pid, &status)) == 0)
	coopth_wait();
    if (retval == -1)
	error("waitpid: %s\n", strerror(errno));
    /* print child exitcode. not perfect */
    g_printf("run_unix_command() (parent): child exit code: %i\n",
            WEXITSTATUS(status));
    return WEXITSTATUS(status);
}

static void chld_crash(int sig)
{
    error("secure child crashed with %i\n", sig);
    exit(7);
}

int unix_run_secure(const char *path, int pos, struct popen2 *file)
{
    int close_from = STDERR_FILENO + 1;
    pid_t pid;
    int wt, retval;
    sigset_t set, oset;
    int outp[2];
    const char *argv[2];
    pshared_sem_t init_sem, crit_sem;
    struct sigaction act;

    retval = pshared_sem_init(&init_sem, 0);
    assert(!retval);
    retval = pshared_sem_init(&crit_sem, 0);
    assert(!retval);
    assert(pos < strlen(path));
    argv[0] = path + pos;
    argv[1] = NULL;	/* no args allowed */
    retval = pipe(outp);
    assert(!retval);
    signal_block_async_nosig(&oset);
    sigprocmask(SIG_SETMASK, NULL, &set);
    /* fork child */
    switch ((pid = fork())) {
    case -1: /* failed */
	sigprocmask(SIG_SETMASK, &oset, NULL);
	g_printf("run_unix_command(): fork() failed\n");
	return -1;
    case 0: /* child */
	pshared_sem_wait(crit_sem);
	retval = priv_drop();
	if (retval)
	    _exit(EXIT_FAILURE);
	pshared_sem_post(init_sem);
	pshared_sem_destroy(&init_sem);
	pshared_sem_destroy(&crit_sem);
	close(0);
	open("/dev/null", O_RDONLY);
	close(1);
	close(2);
	dup(outp[1]);
	dup(outp[1]);
	close(outp[0]);
	close(outp[1]);
#ifdef HAVE_CLOSEFROM
	closefrom(close_from);
#else
	for (; close_from < sysconf(_SC_OPEN_MAX); close_from++)
	    close(close_from);
#endif
	/* close signals, then unblock */
	signal_done();
	/* flush pending signals */
	do {
#ifdef HAVE_SIGTIMEDWAIT
	    struct timespec to = { 0, 0 };
	    wt = sigtimedwait(&set, NULL, &to);
#else
	    int i;
	    sigset_t pending;
	    sigpending(&pending);
	    wt = -1;
	    for (i = 1; i < SIGMAX; i++)
		if (sigismember(&pending, i) && sigismember(&set, i)) {
		    sigwait(&set, NULL);
		    wt = 0;
		}
#endif
	} while (wt != -1);
	sigprocmask(SIG_SETMASK, &oset, NULL);
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wincompatible-pointer-types"
	retval = execve(path, argv, dosemu_envp);	/* execute command */
#pragma GCC diagnostic pop
	error("exec failed: %s\n", strerror(errno));
	_exit(retval);
	break;
    }
    sigchld_set_critical(chld_crash, &act);
    pshared_sem_post(crit_sem);
    pshared_sem_wait(init_sem);
    sigchld_unset_critical(&act);
    sigprocmask(SIG_SETMASK, &oset, NULL);
    pshared_sem_destroy(&init_sem);
    pshared_sem_destroy(&crit_sem);
    close(outp[1]);
    file->from_child = outp[0];
    file->to_child = -1;
    file->child_pid = pid;
    return 1;  // xfer 1 fd
}

/* no PATH searching, no arguments allowed, no stdin, no inherited fds */
int run_unix_secure(const char *prg)
{
    char *path;
    struct popen2 file;
    int pos, err;

    path = assemble_path2(dosemu_exec_dir_path, prg, &pos);
    if (!exists_file(path)) {
	com_printf("unix: %s not found\n", path);
	free(path);
	return -1;
    }
    g_printf("UNIX: run_secure %s '%s'\n", path, prg);
    err = fslib_popen(SUBSYS_UX, dosemu_exec_dir_idx, path, pos, &file);
    free(path);
    if (err)
	return err;
    return do_wait_custom(file.child_pid, file.from_child);
}

/*
 * This function provides parts of the interface to reconfigure parts
 * of X/SDL and the VGA emulation during a DOSEMU session.
 * It is used by the xmode.exe program that comes with DOSEMU.
 */
int change_config(unsigned item, void *buf, int grab_active,
    int kbd_grab_active, int clip_mode)
{
  static char title_emuname [TITLE_EMUNAME_MAXLEN] = {0};
  static char title_appname [TITLE_APPNAME_MAXLEN] = {0};
  int err = 0;

  g_printf("change_config: item = %d, buffer = %p\n", item, buf);

  switch(item) {

    case CHG_TITLE:
      {
	/* high-level write (shows name of emulator + running app) */
	char title [TITLE_EMUNAME_MAXLEN + TITLE_APPNAME_MAXLEN + 35] = {0};
	wchar_t wtitle [sizeof(title)];
	char *unixptr = NULL;
	char *s;

	/* app - DOS in a BOX */
	/* name of running application (if any) */
	if (config.X_title_show_appname && strlen (title_appname))
	  strcpy (title, title_appname);

	/* append name of emulator */
	if (strlen (title_emuname)) {
	    if (strlen (title)) strcat (title, " - ");
	    strcat (title, title_emuname);
	} else if (strlen (config.X_title)) {
	  if (strlen (title)) strcat (title, " - ");
	  unixptr = title + strlen (title);
	  /* foreign string, cannot trust its length to be <= TITLE_EMUNAME_MAXLEN */
	  snprintf (unixptr, TITLE_EMUNAME_MAXLEN, "%s ", config.X_title);
	}

	if (dosemu_frozen) {
	  if (strlen (title)) strcat (title, " ");

	  if (dosemu_user_froze)
	    strcat (title, "[paused - Ctrl+Alt+P] ");
	  else
	    strcat (title, "[background pause] ");
	}

	if (grab_active || kbd_grab_active || clip_mode) {
	  strcat(title, "[");
	  if (kbd_grab_active) {
	    strcat(title, "keyboard");
	    if (grab_active || clip_mode)
	      strcat(title, "+");
	  }
	  if (grab_active) {
	    strcat(title, "mouse");
	    if (clip_mode)
	      strcat(title, "+");
	  }
	  if (clip_mode)
	    strcat(title, "clip");
	  strcat(title, " grab] ");
	}

	/* now actually change the title of the Window */
	if (unixptr == NULL)
	  unixptr = strchr(title, '\0');
	for (s = title; s < unixptr; s++)
	  wtitle[s - title] = dos_to_unicode_table[(unsigned char)*s];
	wtitle[unixptr - title] = 0;
	if (*unixptr) {
	  if (mbstowcs(&wtitle[unixptr - title], unixptr, TITLE_EMUNAME_MAXLEN)
	      == -1)
	    wtitle[unixptr - title] = 0;
	  wtitle[unixptr - title + TITLE_EMUNAME_MAXLEN] = 0;
	}
	Video->change_config (CHG_TITLE, wtitle);
      }
       break;

    case CHG_TITLE_EMUNAME:
      g_printf ("change_config: emu_name = %s\n", (char *) buf);
      snprintf (title_emuname, TITLE_EMUNAME_MAXLEN, "%s", ( char *) buf);
      Video->change_config (CHG_TITLE, NULL);
      break;

    case CHG_TITLE_APPNAME:
      g_printf ("change_config: app_name = %s\n", (char *) buf);
      snprintf (title_appname, TITLE_APPNAME_MAXLEN, "%s", (char *) buf);
      Video->change_config (CHG_TITLE, NULL);
      break;

    case CHG_TITLE_SHOW_APPNAME:
      g_printf("change_config: show_appname %i\n", *((int *) buf));
      config.X_title_show_appname = *((int *) buf);
      Video->change_config (CHG_TITLE, NULL);
      break;

    case CHG_WINSIZE:
      config.X_winsize_x = *((int *) buf);
      config.X_winsize_y = ((int *) buf)[1];
      g_printf("change_config: set initial graphics window size to %d x %d\n", config.X_winsize_x, config.X_winsize_y);
      break;

    case CHG_BACKGROUND_PAUSE:
      g_printf("change_config: background_pause %i\n", *((int *) buf));
      config.X_background_pause = *((int *) buf);
      break;

    case GET_TITLE_APPNAME:
      snprintf (buf, TITLE_APPNAME_MAXLEN, "%s", title_appname);
      break;

    default:
      err = 100;
  }

  return err;
}

/* set of 4096 addresses rounded down to page boundaries where
   bits 12..23 equal the index: if the page is in this set we quickly
   know that regular reads and writes are valid.
   Initialize with invalid entries */
static dosaddr_t unprotected_page_cache[PAGE_SIZE] = {0xffffffff};
/* software TLB to translate unprotected pages to UNIX addresses */
static unsigned char *unprotected_page_unixaddr_tlb[PAGE_SIZE] = {};

void invalidate_unprotected_page_cache(dosaddr_t addr, int len)
{
  unsigned int page;
  for (page = addr >> PAGE_SHIFT;
       page <= (addr + len - 1) >> PAGE_SHIFT; page++)
    unprotected_page_cache[page & (PAGE_SIZE-1)] = 0xffffffff;
}

/* returns the host address if it's definitely unprotected,
   otherwise NULL */
static inline void *unprotected_dosaddr_to_unixaddr(dosaddr_t addr, int len)
{
  /* hash = low 12 bits of page number, add len-1 to fail on boundaries.
     This gives no clashes if all addresses are under 16MB and >99.99% hit
     rate when addresses over 16MB are present while still using a small
     cache table.
     See http://www.emulators.com/docs/nx08_stlb.htm for background on
     this technique.
   */
  int hash = (addr >> PAGE_SHIFT) & (PAGE_SIZE-1);
  if (unprotected_page_cache[hash] == ((addr + len - 1) & _PAGE_MASK))
    return &unprotected_page_unixaddr_tlb[hash][addr & (PAGE_SIZE-1)];
  else
    return NULL;
}

/* marks the page as unprotected in the cache, and add the host address to
   the TLB */
static inline void set_unprotected_page(dosaddr_t addr, void *uaddr)
{
  int hash = (addr >> PAGE_SHIFT) & (PAGE_SIZE-1);
  unprotected_page_cache[hash] = addr & _PAGE_MASK;
  unprotected_page_unixaddr_tlb[hash] = (void *)((uintptr_t)uaddr & _PAGE_MASK);
}

void default_sim_pagefault_handler(dosaddr_t addr, int err, uint32_t op, int len)
{
  if (err == -1) {
    /* err = -1 is special, hitting JIT protected page */
    e_invalidate(addr, len);
    return;
  }
  if (err & 2)
    dosemu_error("Invalid write to addr %#x, ptr %p, len %d\n",
		 addr, LINEAR2UNIX(addr), len);
  else
    dosemu_error("Invalid read from addr %#x, ptr %p\n",
		 addr, LINEAR2UNIX(addr));
  leavedos_main(1);
}

static void check_read_pagefault(dosaddr_t addr, void *uaddr,
				 sim_pagefault_handler_t handler)
{
  if (addr >= LOWMEM_SIZE + HMASIZE) {
    if (!dpmi_read_access(addr))
      /* uncommitted page is never "present" */
      handler(addr, 4, 0, 0);
    /* only add writable pages to the cache! */
    if (!dpmi_write_access(addr))
      return;
  }
  if (!e_querymprot(addr) && !memcheck_is_rom(addr))
    set_unprotected_page(addr, uaddr);
}

uint8_t do_read_byte(dosaddr_t addr, sim_pagefault_handler_t handler)
{
  void *uaddr = unprotected_dosaddr_to_unixaddr(addr, 1);
  if (!uaddr) {
    /* use vga_write_access instead of vga_read_access here to avoid adding
       read-only addresses to the cache */
    if (vga_write_access(addr))
      return vga_read(addr);
    if (config.mmio_tracing && mmio_check(addr))
      return mmio_trace_byte(addr, READ_BYTE(addr), MMIO_READ);
    uaddr = dosaddr_to_unixaddr(addr);
    check_read_pagefault(addr, uaddr, handler);
  }
  return UNIX_READ_BYTE(uaddr);
}

uint16_t do_read_word(dosaddr_t addr, sim_pagefault_handler_t handler)
{
  void *uaddr = unprotected_dosaddr_to_unixaddr(addr, 2);
  if (!uaddr) {
    if (((addr+1) & (PAGE_SIZE-1)) == 0)
      /* split if spanning a page boundary */
      return do_read_byte(addr, handler) |
	((uint16_t)do_read_byte(addr+1, handler) << 8);
    if (vga_write_access(addr))
      return vga_read_word(addr);
    if (config.mmio_tracing && mmio_check(addr))
      return mmio_trace_word(addr, READ_WORD(addr), MMIO_READ);
    uaddr = dosaddr_to_unixaddr(addr);
    check_read_pagefault(addr, uaddr, handler);
  }
  return UNIX_READ_WORD(uaddr);
}

uint32_t do_read_dword(dosaddr_t addr, sim_pagefault_handler_t handler)
{
  void *uaddr = unprotected_dosaddr_to_unixaddr(addr, 4);
  if (!uaddr) {
    if (((addr+3) & (PAGE_SIZE-1)) < 3)
      return do_read_word(addr, handler) |
	((uint32_t)do_read_word(addr+2, handler) << 16);
    if (vga_write_access(addr))
      return vga_read_dword(addr);
    if (config.mmio_tracing && mmio_check(addr))
      return mmio_trace_dword(addr, READ_DWORD(addr), MMIO_READ);
    uaddr = dosaddr_to_unixaddr(addr);
    check_read_pagefault(addr, uaddr, handler);
  }
  return UNIX_READ_DWORD(uaddr);
}

uint64_t do_read_qword(dosaddr_t addr, sim_pagefault_handler_t handler)
{
  return do_read_dword(addr, handler) |
    ((uint64_t)do_read_dword(addr+4, handler) << 32);
}

static int check_write_pagefault(dosaddr_t addr, void *uaddr, uint32_t op, int len,
				 sim_pagefault_handler_t handler)
{
  if (addr >= LOWMEM_SIZE + HMASIZE && !dpmi_write_access(addr)) {
    handler(addr, 6 + dpmi_read_access(addr), op, len);
    return 1;
  }
  if (e_querymprot(addr))
    /* handle invalidations for writes to JIT protected pages */
    handler(addr, -1, op, len);
  else if (!memcheck_is_rom(addr))
    set_unprotected_page(addr, uaddr);
  return 0;
}

void do_write_byte(dosaddr_t addr, uint8_t byte, sim_pagefault_handler_t handler)
{
  void *uaddr = unprotected_dosaddr_to_unixaddr(addr, 1);
  if (!uaddr) {
    if (vga_write_access(addr)) {

      vga_write(addr, byte);
      return;
    }
    if (config.mmio_tracing && mmio_check(addr))
      mmio_trace_byte(addr, byte, MMIO_WRITE);
    uaddr = dosaddr_to_unixaddr(addr);
    if (check_write_pagefault(addr, uaddr, byte, 1, handler))
      return;
  }
  UNIX_WRITE_BYTE(uaddr, byte);
}

void do_write_word(dosaddr_t addr, uint16_t word, sim_pagefault_handler_t handler)
{
  void *uaddr = unprotected_dosaddr_to_unixaddr(addr, 2);
  if (!uaddr) {
    if (((addr+1) & (PAGE_SIZE-1)) == 0) {
      do_write_byte(addr, word & 0xff, handler);
      do_write_byte(addr+1, word >> 8, handler);
      return;
    }
    if (vga_write_access(addr)) {
      vga_write_word(addr, word);
      return;
    }
    if (config.mmio_tracing && mmio_check(addr))
      mmio_trace_word(addr, word, MMIO_WRITE);
    uaddr = dosaddr_to_unixaddr(addr);
    if (check_write_pagefault(addr, uaddr, word, 2, handler))
      return;
  }
  UNIX_WRITE_WORD(uaddr, word);
}

void do_write_dword(dosaddr_t addr, uint32_t dword, sim_pagefault_handler_t handler)
{
  void *uaddr = unprotected_dosaddr_to_unixaddr(addr, 4);
  if (!uaddr) {
    if (((addr+3) & (PAGE_SIZE-1)) < 3) {
      do_write_word(addr, dword & 0xffff, handler);
      do_write_word(addr+2, dword >> 16, handler);
      return;
    }
    if (vga_write_access(addr)) {
      vga_write_dword(addr, dword);
      return;
    }
    if (config.mmio_tracing && mmio_check(addr))
      mmio_trace_dword(addr, dword, MMIO_WRITE);
    uaddr = dosaddr_to_unixaddr(addr);
    if (check_write_pagefault(addr, uaddr, dword, 4, handler))
      return;
  }
  UNIX_WRITE_DWORD(uaddr, dword);
}

void do_write_qword(dosaddr_t addr, uint64_t qword, sim_pagefault_handler_t handler)
{
  do_write_dword(addr, qword & 0xffffffff, handler);
  do_write_dword(addr+4, qword >> 32, handler);
}

uint8_t read_byte(dosaddr_t addr)
{
  return do_read_byte(addr, default_sim_pagefault_handler);
}

uint16_t read_word(dosaddr_t addr)
{
  return do_read_word(addr, default_sim_pagefault_handler);
}

uint32_t read_dword(dosaddr_t addr)
{
  return do_read_dword(addr, default_sim_pagefault_handler);
}

uint64_t read_qword(dosaddr_t addr)
{
  return do_read_qword(addr, default_sim_pagefault_handler);
}

void write_byte(dosaddr_t addr, uint8_t byte)
{
  do_write_byte(addr, byte, default_sim_pagefault_handler);
}

void write_word(dosaddr_t addr, uint16_t word)
{
  do_write_word(addr, word, default_sim_pagefault_handler);
}

void write_dword(dosaddr_t addr, uint32_t dword)
{
  do_write_dword(addr, dword, default_sim_pagefault_handler);
}

void write_qword(dosaddr_t addr, uint64_t qword)
{
  do_write_qword(addr, qword, default_sim_pagefault_handler);
}

void memcpy_2unix(void *dest, dosaddr_t src, size_t n)
{
  if (vga.inst_emu && src >= 0xa0000 && src < 0xc0000)
    memcpy_from_vga(dest, src, n);
  else while (n) {
    /* EMS can produce the non-contig mapping. We need to iterate it
     * page-by-page or use a separate alias window... */
    dosaddr_t bound = (src & _PAGE_MASK) + PAGE_SIZE;
    size_t to_copy = _min(n, bound - src);
    MEMCPY_2UNIX(dest, src, to_copy);
    src += to_copy;
    dest += to_copy;
    n -= to_copy;
  }
}

void memcpy_2dos(dosaddr_t dest, const void *src, size_t n)
{
  if (vga.inst_emu && dest >= 0xa0000 && dest < 0xc0000)
    memcpy_to_vga(dest, src, n);
  else {
    e_invalidate(dest, n);
    while (n) {
      dosaddr_t bound = (dest & _PAGE_MASK) + PAGE_SIZE;
      size_t to_copy = _min(n, bound - dest);
      MEMCPY_2DOS(dest, src, to_copy);
      src += to_copy;
      dest += to_copy;
      n -= to_copy;
    }
  }
}

void memset_dos(dosaddr_t dest, char ch, size_t n)
{
  if (vga.inst_emu && dest >= 0xa0000 && dest < 0xc0000)
    vga_memset(dest, ch, n);
  else {
    e_invalidate(dest, n);
    while (n) {
      dosaddr_t bound = (dest & _PAGE_MASK) + PAGE_SIZE;
      size_t to_copy = _min(n, bound - dest);
      MEMSET_DOS(dest, ch, to_copy);
      dest += to_copy;
      n -= to_copy;
    }
  }
}

void memmove_dos2dos(dosaddr_t dest, dosaddr_t src, size_t n)
{
  /* XXX GW (Game Wizard Pro) does this.
     TODO: worry about overlaps; could be a little cleaner
     using the memcheck.c mechanism */
  if (vga.inst_emu && src >= 0xa0000 && src < 0xc0000)
    memcpy_dos_from_vga(dest, src, n);
  else if (vga.inst_emu && dest >= 0xa0000 && dest < 0xc0000)
    memcpy_dos_to_vga(dest, src, n);
  else {
    e_invalidate(dest, n);
    while (n) {
      dosaddr_t bound1 = (src & _PAGE_MASK) + PAGE_SIZE;
      dosaddr_t bound2 = (dest & _PAGE_MASK) + PAGE_SIZE;
      size_t to_copy1 = _min(bound1 - src, bound2 - dest);
      size_t to_copy = _min(n, to_copy1);
      MEMMOVE_DOS2DOS(dest, src, to_copy);
      src += to_copy;
      dest += to_copy;
      n -= to_copy;
    }
  }
}

void memcpy_dos2dos(unsigned dest, unsigned src, size_t n)
{
  /* Jazz Jackrabbit does DOS read to VGA via protmode selector */
  if (vga.inst_emu && src >= 0xa0000 && src < 0xc0000)
    memcpy_dos_from_vga(dest, src, n);
  else if (vga.inst_emu && dest >= 0xa0000 && dest < 0xc0000)
    memcpy_dos_to_vga(dest, src, n);
  else {
    e_invalidate(dest, n);
    while (n) {
      dosaddr_t bound1 = (src & _PAGE_MASK) + PAGE_SIZE;
      dosaddr_t bound2 = (dest & _PAGE_MASK) + PAGE_SIZE;
      size_t to_copy1 = _min(bound1 - src, bound2 - dest);
      size_t to_copy = _min(n, to_copy1);
      MEMCPY_DOS2DOS(dest, src, to_copy);
      src += to_copy;
      dest += to_copy;
      n -= to_copy;
    }
  }
}

int unix_read(int fd, void *data, int cnt)
{
  return RPT_SYSCALL(read(fd, data, cnt));
}

int dos_read(int fd, unsigned data, int cnt)
{
  int ret;
  /* GW also reads or writes directly from a file to protected video memory. */
  if (vga.inst_emu && data >= 0xa0000 && data < 0xc0000) {
    char buf[cnt];
    ret = unix_read(fd, buf, cnt);
    if (ret >= 0)
      memcpy_to_vga(data, buf, ret);
  }
  else
    ret = unix_read(fd, LINEAR2UNIX(data), cnt);
  if (ret > 0)
	e_invalidate(data, ret);
  return (ret);
}

int unix_write(int fd, const void *data, int cnt)
{
  return RPT_SYSCALL(write(fd, data, cnt));
}

int dos_write(int fd, unsigned data, int cnt)
{
  int ret;
  const unsigned char *d;
  unsigned char *buf;

  if (!cnt)
    return 0;
  buf = alloca(cnt);
  if (vga.inst_emu && data >= 0xa0000 && data < 0xc0000) {
    memcpy_from_vga(buf, data, cnt);
    d = buf;
  } else {
    d = LINEAR2UNIX(data);
  }
  ret = unix_write(fd, d, cnt);
  g_printf("Wrote %10.10s\n", d);
  return (ret);
}

#define BUF_SIZE 1024
int com_vsnprintf(char *str, size_t msize, const char *format, va_list ap)
{
	char *s = str;
	int i, size;
	char scratch[BUF_SIZE];

	assert(msize <= BUF_SIZE);
	size = vsnprintf(scratch, msize, format, ap);
	for (i=0; i < size; i++) {
		if (s - str >= msize - 1)
			break;
		if (scratch[i] == '\n') {
			*s++ = '\r';
			if (s - str >= msize - 1)
				break;
		}
		*s++ = scratch[i];
	}
	if (msize)
		*s = 0;
	return s - str;
}

int com_vsprintf(char *str, const char *format, va_list ap)
{
	return com_vsnprintf(str, BUF_SIZE, format, ap);
}

int com_sprintf(char *str, const char *format, ...)
{
	va_list ap;
	int ret;
	va_start(ap, format);

	ret = com_vsprintf(str, format, ap);
	va_end(ap);
	return ret;
}

int com_vfprintf(int dosfilefd, const char *format, va_list ap)
{
	int size;
	char scratch2[BUF_SIZE];

	size = com_vsprintf(scratch2, format, ap);
	if (!size) return 0;
	return com_doswrite(dosfilefd, scratch2, size);
}

int com_vprintf(const char *format, va_list ap)
{
	int size;
	char scratch2[BUF_SIZE];

	size = com_vsprintf(scratch2, format, ap);
	if (!size) return 0;
	return com_dosprint(scratch2);
}

int com_fprintf(int dosfilefd, const char *format, ...)
{
	va_list ap;
	int ret;
	va_start(ap, format);

	ret = com_vfprintf(dosfilefd, format, ap);
	va_end(ap);
	return ret;
}

int com_printf(const char *format, ...)
{
	va_list ap;
	int ret;
	va_start(ap, format);

	ret = com_vprintf(format, ap);
	va_end(ap);
	return ret;
}

int com_error(const char *format, ...)
{
	int ret;
	va_list args;
	va_start(args, format);
	ret = com_vprintf(format, args);
	va_end(args);
	va_start(args, format);
	verror(format, args);
	va_end(args);
	return ret;
}

int com_puts(const char *s)
{
	return com_printf("%s", s);
}

char *skip_white_and_delim(char *s, int delim)
{
	while (*s && isspace(*s)) s++;
	if (*s == delim) s++;
	while (*s && isspace(*s)) s++;
	return s;
}

void call_msdos(void)
{
	do_int_call_back(0x21);
}

int com_doswrite(int dosfilefd, const char *buf32, u_short size)
{
	char *s;
	u_short int23_seg, int23_off;
	int ret = -1;

	if (!size) return 0;
	com_errno = 8;
	s = lowmem_alloc(size);
	if (!s) return -1;
	memcpy(s, buf32, size);
	pre_msdos();
	LWORD(ecx) = size;
	LWORD(ebx) = dosfilefd;
	SREG(ds) = DOSEMU_LMHEAP_SEG;
	LWORD(edx) = DOSEMU_LMHEAP_OFFS_OF(s);
	LWORD(eax) = 0x4000;	/* write handle */
	/* write() can be interrupted with ^C. Therefore we set int0x23 here
	 * so that even in this case it will return to the proper place. */
	int23_seg = ISEG(0x23);
	int23_off = IOFF(0x23);
	SETIVEC(0x23, CBACK_SEG, CBACK_OFF);
	call_msdos();	/* call MSDOS */
	SETIVEC(0x23, int23_seg, int23_off);	/* restore 0x23 ASAP */
	lowmem_free(s);
	if (LWORD(eflags) & CF)
		com_errno = LWORD(eax);
	else
		ret = LWORD(eax);
	post_msdos();
	return ret;
}

int com_dosread(int dosfilefd, char *buf32, u_short size)
{
	char *s;
	u_short int23_seg, int23_off;
	int ret = -1;

	if (!size) return 0;
	com_errno = 8;
	s = lowmem_alloc(size);
	if (!s) return -1;
	pre_msdos();
	LWORD(ecx) = size;
	LWORD(ebx) = dosfilefd;
	SREG(ds) = DOSEMU_LMHEAP_SEG;
	LWORD(edx) = DOSEMU_LMHEAP_OFFS_OF(s);
	LWORD(eax) = 0x3f00;
	/* read() can be interrupted with ^C, esp. when it reads from a
	 * console. Therefore we set int0x23 here so that even in this
	 * case it will return to the proper place. */
	int23_seg = ISEG(0x23);
	int23_off = IOFF(0x23);
	SETIVEC(0x23, CBACK_SEG, CBACK_OFF);
	call_msdos();	/* call MSDOS */
	SETIVEC(0x23, int23_seg, int23_off);	/* restore 0x23 ASAP */
	if (LWORD(eflags) & CF) {
		com_errno = LWORD(eax);
	} else {
		memcpy(buf32, s, _min(size, LWORD(eax)));
		ret = LWORD(eax);
	}
	post_msdos();
	lowmem_free(s);
	return ret;
}

int com_dosreadcon(char *buf32, u_short size)
{
	u_short rd;

	if (!size)
		return 0;
	pre_msdos();
	for (rd = 0; rd < size; rd++) {
		LWORD(eax) = 0x600;
		LO(dx) = 0xff;
		call_msdos();
		if (LWORD(eflags) & ZF)
			break;
		buf32[rd] = LO(ax);
	}
	post_msdos();
	return rd;
}

int com_doswritecon(const char *buf32, u_short size)
{
	return com_doswrite(STDOUT_FILENO, buf32, size);
}

int com_dosprint(const char *buf32)
{
	return com_doswritecon(buf32, strlen(buf32));
}

int com_dosopen(const char *name, int flags)
{
	int ret = -1;
	int len = strlen(name) + 1;
	char *s = lowmem_alloc(len);
	strcpy(s, name);
	pre_msdos();
	HI(ax) = 0x3d;
	switch (flags & O_ACCMODE) {
	case O_RDONLY:
	default:
		LO(ax) = 0;
		break;
	case O_WRONLY:
		LO(ax) = 1;
		break;
	case O_RDWR:
		LO(ax) = 2;
		break;
	}
	if (flags & O_CLOEXEC)
		LO(ax) |= 1 << 7;
	SREG(ds) = DOSEMU_LMHEAP_SEG;
	LWORD(edx) = DOSEMU_LMHEAP_OFFS_OF(s);
	LWORD(ecx) = 0;
	call_msdos();
	if (LWORD(eflags) & CF)
		com_errno = LWORD(eax);
	else
		ret = LWORD(eax);
	post_msdos();
	lowmem_free(s);
	return ret;
}

int com_dosclose(int fd)
{
	int ret = -1;
	pre_msdos();
	HI(ax) = 0x3e;
	LWORD(ebx) = fd;
	call_msdos();
	if (LWORD(eflags) & CF)
		com_errno = LWORD(eax);
	else
		ret = 0;
	post_msdos();
	return ret;
}

int com_bioscheckkey(void)
{
	int ret;
	pre_msdos();
	HI(ax) = 1;
	do_int_call_back(0x16);
	ret = !(LWORD(eflags) & ZF);
	post_msdos();
	return ret;
}

int com_biosgetch(void)
{
	int ret;
	do {
		ret = com_bioscheckkey();
	} while (!ret);
	pre_msdos();
	HI(ax) = 0;
	do_int_call_back(0x16);
	ret = LO(ax);
	post_msdos();
	return ret;
}

int com_biosread(char *buf32, u_short size)
{
	u_short rd = 0;
	int ch;

	if (!size) return 0;
	while (rd < size) {
		ch = com_biosgetch();
		if (ch == '\b') {
			if (rd > 0) {
				p_dos_str("\b \b");
				rd--;
			}
			continue;
		}
		if (ch != '\r')
			buf32[rd++] = ch;
		else
			buf32[rd++] = '\n';
		p_dos_str("%c", buf32[rd - 1]);
		if (ch == '\r' || ch == '\3')
			break;
	}
	return rd;
}

int com_setcbreak(int on)
{
	int old_b;
	pre_msdos();
	LWORD(eax) = 0x3300;
	call_msdos();
	old_b = LO(dx);
	LO(ax) = 1;
	LO(dx) = on;
	call_msdos();
	post_msdos();
	return old_b;
}

int com_dosallocmem(u_short para)
{
    int ret;
    pre_msdos();
    HI(ax) = 0x48;
    LWORD(ebx) = para;
    call_msdos();
    if (REG(eflags) & CF)
        ret = 0;
    else
        ret = LWORD(eax);
    post_msdos();
    return ret;
}

int com_dosfreemem(u_short para)
{
    int ret = 0;
    pre_msdos();
    HI(ax) = 0x49;
    SREG(es) = para;
    call_msdos();
    if (REG(eflags) & CF)
        ret = -1;
    post_msdos();
    return ret;
}

/* Output a character to the screen. */
void char_out(unsigned char ch, int page)
{
	struct vm86_regs saved_regs = REGS;
	HI(ax) = 0xe;
	LO(ax) = ch;
	HI(bx) = page;
	LO(bx) = 7;
	do_int_call_back(0x10);
	REGS = saved_regs;
}

unsigned char sdb_drive_letter(sdb_t sdb)
{
    return (*(u_char  *)&sdb[sdb_drive_letter_off]);
}
char *sdb_template_name(sdb_t sdb)
{
    return ((char     *)&sdb[sdb_template_name_off]);
}
char *sdb_template_ext(sdb_t sdb)
{
    return ((char     *)&sdb[sdb_template_ext_off]);
}
unsigned char sdb_attribute(sdb_t sdb)
{
    return (*(u_char  *)&sdb[sdb_attribute_off]);
}
unsigned short sdb_dir_entry(sdb_t sdb)
{
    return (*(u_short *)&sdb[sdb_dir_entry_off]);
}
unsigned short sdb_p_cluster(sdb_t sdb)
{
    return (*(u_short *)&sdb[sdb_p_cluster_off]);
}
char *sdb_file_name(sdb_t sdb)
{
    return ((char     *)&sdb[sdb_file_name_off]);
}
char *sdb_file_ext(sdb_t sdb)
{
    return ((char     *)&sdb[sdb_file_ext_off]);
}
unsigned char sdb_file_attr(sdb_t sdb)
{
    return (*(u_char  *)&sdb[sdb_file_attr_off]);
}
unsigned short sdb_file_time(sdb_t sdb)
{
    return (*(u_short *)&sdb[sdb_file_time_off]);
}
unsigned short sdb_file_date(sdb_t sdb)
{
    return (*(u_short *)&sdb[sdb_file_date_off]);
}
unsigned short sdb_file_st_cluster(sdb_t sdb)
{
    return (*(u_short *)&sdb[sdb_file_st_cluster_off]);
}
Bit32u sdb_file_size(sdb_t sdb)
{
    return (*(u_int   *)&sdb[sdb_file_size_off]);
}

unsigned short sft_handle_cnt(sft_t sft)
{
    return (*(u_short *)&sft[sft_handle_cnt_off]);
}
unsigned short sft_open_mode(sft_t sft)
{
    return (*(u_short *)&sft[sft_open_mode_off]);
}
unsigned char sft_attribute_byte(sft_t sft)
{
    return (*(u_char  *)&sft[sft_attribute_byte_off]);
}
unsigned short sft_device_info(sft_t sft)
{
    return (*(u_short *)&sft[sft_device_info_off]);
}
Bit32u sft_dev_drive_ptr(sft_t sft)
{
    return (*(u_int   *)&sft[sft_dev_drive_ptr_off]);
}
unsigned short sft_start_cluster(sft_t sft)
{
    return (*(u_short *)&sft[sft_start_cluster_off]);
}
unsigned short sft_time(sft_t sft)
{
    return (*(u_short *)&sft[sft_time_off]);
}
unsigned short sft_date(sft_t sft)
{
    return (*(u_short *)&sft[sft_date_off]);
}
Bit32u sft_size(sft_t sft)
{
    return (*(u_int   *)&sft[sft_size_off]);
}
Bit32u sft_position(sft_t sft)
{
    return (*(u_int   *)&sft[sft_position_off]);
}
unsigned short sft_rel_cluster(sft_t sft)
{
    return (*(u_short *)&sft[sft_rel_cluster_off]);
}
unsigned short sft_abs_cluster(sft_t sft)
{
    return (*(u_short *)&sft[sft_abs_cluster_off]);
}
unsigned short sft_directory_sector(sft_t sft)
{
    return (*(u_short *)&sft[sft_directory_sector_off]);
}
unsigned char sft_directory_entry(sft_t sft)
{
    return (*(u_char  *)&sft[sft_directory_entry_off]);
}
char *sft_name(sft_t sft)
{
    return ( (char    *)&sft[sft_name_off]);
}
char *sft_ext(sft_t sft)
{
    return ( (char    *)&sft[sft_ext_off]);
}
unsigned short sft_fd(sft_t sft)
{
    return (*(u_short *)&sft[sft_fd_off]);
}

dosaddr_t sda_current_dta(sda_t sda)
{
    if (!sda)
	return 0;
    return (FARADDR((far_t *)&sda[sda_current_dta_off]));
}
unsigned short sda_error_code(sda_t sda)
{
    if (!sda)
	return 0;
    return (*(u_short *)&sda[4]);
}
unsigned short sda_cur_psp(sda_t sda)
{
    if (!sda)
	return 0;
    return (*(u_short *)&sda[sda_cur_psp_off]);
}
unsigned char sda_cur_drive(sda_t sda)
{
    if (!sda)
	return 0;
    return (*(u_char *)&sda[sda_cur_drive_off]);
}
char *sda_filename1(sda_t sda)
{
    if (!sda)
	return NULL;
    return ((char  *)&sda[sda_filename1_off]);
}
char *sda_filename2(sda_t sda)
{
    if (!sda)
	return NULL;
    return ((char  *)&sda[sda_filename2_off]);
}
sdb_t sda_sdb(sda_t sda)
{
    if (!sda)
	return NULL;
    return ((sdb_t    )&sda[sda_sdb_off]);
}
cds_t sda_cds(sda_t sda)
{
    if (!sda)
	return NULL;
    return ((cds_t)(FARPTR((far_t *)&sda[sda_cds_off])));
}
unsigned char sda_search_attribute(sda_t sda)
{
    if (!sda)
	return 0;
    return (*(u_char *)&sda[sda_search_attribute_off]);
}
unsigned char sda_open_mode(sda_t sda)
{
    if (!sda)
	return 0;
    return (*(u_char *)&sda[sda_open_mode_off]);
}
sdb_t sda_rename_source(sda_t sda)
{
    if (!sda)
	return NULL;
    return ((sdb_t    )&sda[sda_rename_source_off]);
}
char *sda_user_stack(sda_t sda)
{
    if (!sda)
	return NULL;
    return ((char *)(FARPTR((far_t *)&sda[sda_user_stack_off])));
}

/*
 *  Data for extended open/create operations, DOS 4 or greater:
 */
unsigned short sda_ext_act(sda_t sda)
{
    return (*(u_short *)&sda[sda_ext_act_off]);
}
unsigned short sda_ext_attr(sda_t sda)
{
    return (*(u_short *)&sda[sda_ext_attr_off]);
}
unsigned short sda_ext_mode(sda_t sda)
{
    return (*(u_short *)&sda[sda_ext_mode_off]);
}

unsigned short psp_parent_psp(psp_t psp)
{
    return (*(u_short *)&psp[0x16]);
}
char *psp_handles(psp_t psp)
{
    return ((char *)(FARPTR((far_t *)&psp[0x34])));
}

far_t lol_dpbfarptr(lol_t lol)
{
    return (rFAR_FARt(READ_DWORD((lol)+lol_dpbfarptr_off)));
}
far_t lol_cdsfarptr(lol_t lol)
{
    return (rFAR_FARt(READ_DWORD((lol)+lol_cdsfarptr_off)));
}
char lol_last_drive(lol_t lol)
{
    return (READ_BYTE((lol)+lol_last_drive_off));
}
// lol_nuldev(lol_t lol)		        ((lol)+lol_nuldev_off)
// lol_njoined(lol_t lol)		((lol)+lol_njoined_off)

void set_exit_after_load(void)
{
    misc_e6_store_options("DOSEMU_EXIT=1");
}

void set_boot_cls(void)
{
    misc_e6_store_options("DOSEMU_BOOT_CLS=1");
}

void set_boot_showwin(void)
{
    misc_e6_store_options("DOSEMU_BOOT_SHOWWIN=1");
}
