Date: Wed, 30 Aug 2000 02:48:07 +0900 (JST) From: Tatsuya Kudoh <cdr@cosmonet.org> To: FreeBSD-gnats-submit@freebsd.org Subject: i386/20925: doscmd(1) does not truncate a file Message-ID: <200008291744.CAA02429@planar.cosmonet.org>
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>Number: 20925
>Category: i386
>Synopsis: doscmd(1) does not truncate a file int write functio-call.
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Tue Aug 29 11:00:01 PDT 2000
>Closed-Date:
>Last-Modified:
>Originator: Tatsuya Kudoh
>Release: FreeBSD 3.5-RELEASE i386
>Organization:
>Environment:
FreeBSD 3.2 or later
kernel compiled with 'options "VM86"'
>Description:
Under MS-DOS, the write function-call with size parameter is 0,
it means file truncating.
This function is not implemented in doscmd(1).
>How-To-Repeat:
Some MS-DOS applications. In my environment, LSI Japans's
LSI C-86 C compiler does not work.
>Fix:
This is a patch for dsmcd(1) on 3.5-RELEASE
-------------------------------------------
*** dos.c.old Sat Aug 12 22:36:06 2000
--- dos.c Sat Aug 12 22:42:08 2000
***************
*** 1308,1313 ****
--- 1308,1329 ----
** write
*/
static int
+ write_or_truncate(int fd, char *addr, int len)
+ {
+ off_t offset;
+
+ if ( len == 0 ){
+ offset = lseek(fd,0,SEEK_CUR);
+ if( offset < 0 )
+ return -1;
+ else
+ return ftruncate(fd,offset);
+ } else {
+ return write(fd,addr,len);
+ }
+ }
+
+ static int
int21_40(regcontext_t *REGS)
{
char *addr;
***************
*** 1321,1327 ****
switch (R_BX) {
case 0:
if (redirect0) {
! n = write (R_BX, addr, nbytes);
break;
}
n = nbytes;
--- 1337,1343 ----
switch (R_BX) {
case 0:
if (redirect0) {
! n = write_or_truncate (R_BX, addr, nbytes);
break;
}
n = nbytes;
***************
*** 1330,1336 ****
break;
case 1:
if (redirect1) {
! n = write (R_BX, addr, nbytes);
break;
}
n = nbytes;
--- 1346,1352 ----
break;
case 1:
if (redirect1) {
! n = write_or_truncate (R_BX, addr, nbytes);
break;
}
n = nbytes;
***************
*** 1339,1345 ****
break;
case 2:
if (redirect2) {
! n = write (R_BX, addr, nbytes);
break;
}
n = nbytes;
--- 1355,1361 ----
break;
case 2:
if (redirect2) {
! n = write_or_truncate (R_BX, addr, nbytes);
break;
}
n = nbytes;
***************
*** 1347,1353 ****
tty_write(*addr++, -1);
break;
default:
! n = write (R_BX, addr, nbytes);
break;
}
if (n < 0)
--- 1363,1369 ----
tty_write(*addr++, -1);
break;
default:
! n = write_or_truncate (R_BX, addr, nbytes);
break;
}
if (n < 0)
>Release-Note:
>Audit-Trail:
>Unformatted:
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