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Mail Archives: cygwin-developers/1999/01/11/06:31:38

From: cgf AT cygnus DOT com (Christopher Faylor)
Subject: Re: fhandler_console bug
11 Jan 1999 06:31:38 -0800 :
Message-ID: <19990111091746.A18301.cygnus.cygwin32.developers@cygnus.com>
References: <uww2uknsv DOT fsf AT parvati DOT will DOT or DOT jp>
Mime-Version: 1.0
To: Kazuhiro Fujieda <fujieda AT jaist DOT ac DOT jp>, cygwin32-developers AT cygnus DOT com

I've added code to fhandler_console.cc which specifically handles EOF.
It will be in the next snapshot.

Thanks for finding this.

-chris

On Mon, Jan 11, 1999 at 09:16:00PM +0900, Kazuhiro Fujieda wrote:
>The following program is hanged up when Return and ^Z are typed
>continuously in notty mode on Win95.
>
>#include <stdio.h>
>main()
>{
>    int ch;
>    while ((ch = fgetc(stdin)) != EOF) {
>	printf("ch = %02x\n", ch);
>    }
>}
>
>The reason of it is in fhandler_console.cc:1143-1157.
>
>1142:	  copied_chars = 0x12345678;
>1143:	  if ((res = ReadFile (hndl, buf, lenin, &copied_chars, NULL)) &&
>1144:	      copied_chars == 0x12345678)
>
>When ^Z is typed, ReadFile catch the EOF and set copied_char is 0.
>But the succeeding code take no account of this case.  On Win95,
>ReadFile doesn't modify the contents of buf in this case, so
>buf[0] is still '\n' and the program is crushed by the following
>code.
>
>1153:	  if (!looped++ && buf[0] == '\n')
>1154:	    {
>1155:	      if (!--copied_chars)
>1156:		continue;
>1157:	      memcpy (buf, buf + 1, copied_chars);
>____
>  | AIST      Kazuhiro Fujieda <fujieda AT jaist DOT ac DOT jp>
>  | HOKURIKU  School of Information Science
>o_/ 1990      Japan Advanced Institute of Science and Technology
>

-- 
cgf AT cygnus DOT com
http://www.cygnus.com/

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