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/* $id$
$Locker: $ $Name: $ $State: Exp $
* Check if the passed filename is a CP/M style device
*
* These device names must not contain any drive or path or
* extension component, but have a colon ':' at their end.
*
* Return:
* 0: no
* else: yes; fnam contains a valid filename now
* To handle CP/M style devices, like "CON:" and "LPT1:", which
* are not understood by the DOS kernel directly, these functions
* wrap the open() and fopen() functions and deal with it.
*
* Also included are some low-level functions dealing with
* file descriptors, such as "isadev()".
This file bases on OPENF.C of FreeCOM v0.81 beta 1.
$Log: openf.c,v $
Revision 1.1 2001/04/12 00:33:53 skaus
chg: new structure
chg: If DEBUG enabled, no available commands are displayed on startup
fix: PTCHSIZE also patches min extra size to force to have this amount
of memory available on start
bugfix: CALL doesn't reset options
add: PTCHSIZE to patch heap size
add: VSPAWN, /SWAP switch, .SWP resource handling
bugfix: COMMAND.COM A:\
bugfix: CALL: if swapOnExec == ERROR, no change of swapOnExec allowed
add: command MEMORY
bugfix: runExtension(): destroys command[-2]
add: clean.bat
add: localized CRITER strings
chg: use LNG files for hard-coded strings (hangForEver(), init.c)
via STRINGS.LIB
add: DEL.C, COPY.C, CBREAK.C: STRINGS-based prompts
add: fixstrs.c: prompts & symbolic keys
add: fixstrs.c: backslash escape sequences
add: version IDs to DEFAULT.LNG and validation to FIXSTRS.C
chg: splitted code apart into LIB\*.c and CMD\*.c
bugfix: IF is now using error system & STRINGS to report errors
add: CALL: /N
*/
#include "../config.h"
#include <assert.h>
#include <dos.h>
#include <fcntl.h>
#include <io.h>
#include <stdio.h>
#include <string.h>
#include "../include/openf.h"
/*
* Just for the algorithm:
* One could just transform the "XXXX:" style into
* "\dev\XXXX". However, WinNT DOSbox does not support
* this as it seems ("copy \dev\con test" says path not found).
*
* On the other hand, how many other DOS clones don't support
* the \DEV\ prefix, too?
*
* So I open the device and check the handle if it's connected to
* a character device rather than a block device.
*/
int isDeviceName(char *const fnam)
{
char *p;
assert(fnam);
if ((p = strpbrk(fnam, ":\\/")) != 0 /* has a colon or path component */
&& *p == ':' /* has colon --> no path component */
&& p[1] == '\0' /* at end of string */
&& p >= fnam + 2)
{ /* no simple drive letter */
int fd;
*p = '\0'; /* strip off the colon to make it valid for DOS */
/* open with read access only to prevent from creating
disk fiels accidently */
if ((fd = open(fnam, O_RDONLY)) >= 0)
{ /* open OK */
int rv;
/* check for character device */
rv = isadev(fd);
close(fd);
if (rv)
return 1; /* is device name */
}
*p = ':'; /* restore the original filename */
}
return 0; /* no device name */
}
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