[Fwd: Strange-Dangerous behaviour in Cygwin]

[Carlo Florendo]

Paul Eggert wrote:

>Jim Meyering <jim@meyering.net> writes:
>
>  
>
>>Alternative opinions (or patches to yesno.c) welcome.
>>    
>>
>
>In the POSIX locale we don't have any choice; we have to accept
>any answer with a leading "y" as "yes".  See:
>
>http://www.opengroup.org/onlinepubs/000095399/basedefs/xbd_chap07.html#tag_07_03_06_01
>
>Come to think of it, coreutils is too generous, as it ignores leading
>white space; POSIX doesn't allow this, and Solaris 9 agrees with
>POSIX.  GNU used to agree with POSIX until Ulrich Drepper's change
>dated 1996 to use rpmatch if available, and I think the disagreement
>with POSIX was unintended.  So I installed this patch.  (It's not
>often that I get to fix one of his bugs!  :-)
>
>2005-05-08  Paul Eggert  <eggert@cs.ucla.edu>
>
>	* NEWS: cp, ln, mv, rm no longer discard white space when intepreting
>	responses.
>	* lib/yesno.c: Include getline.h, not ctype.h.
>	(yesno): Don't remove leading white space; POSIX doesn't allow it.
>	Use getline to remove arbitrary restriction on response length.
>
>--- NEWS	6 May 2005 17:56:49 -0000	1.286
>+++ NEWS	8 May 2005 16:52:17 -0000
>@@ -50,6 +50,12 @@ GNU coreutils NEWS                      
> 
> ** Changes for better conformance to POSIX
> 
>+  cp, ln, mv, rm changes:
>+
>+    Leading white space is now significant in responses to yes-or-no questions.
>+    For example, if "rm" asks "remove regular file `foo'?" and you respond
>+    with " y" (i.e., space before "y"), it counts as "no".
>+
>   dd changes:
> 
>     On a QUIT or PIPE signal, dd now exits without printing statistics.
>--- lib/yesno.c	4 Oct 2004 20:18:43 -0000	1.12
>+++ lib/yesno.c	8 May 2005 16:46:42 -0000
>@@ -1,5 +1,7 @@
> /* yesno.c -- read a yes/no response from stdin
>-   Copyright (C) 1990, 1998, 2001, 2003, 2004 Free Software Foundation, Inc.
>+
>+   Copyright (C) 1990, 1998, 2001, 2003, 2004, 2005 Free Software
>+   Foundation, Inc.
> 
>    This program is free software; you can redistribute it and/or modify
>    it under the terms of the GNU General Public License as published by
>@@ -21,36 +23,31 @@
> 
> #include "yesno.h"
> 
>-#include <ctype.h>
> #include <stdlib.h>
> #include <stdio.h>
> 
>-#if USE_UNLOCKED_IO
>-# include "unlocked-io.h"
>-#endif
>+#include "getline.h"
> 
>-/* Read one line from standard input
>-   and return nonzero if that line begins with y or Y,
>-   otherwise return 0. */
>+/* Return true if we read an affirmative line from standard input.  */
> 
> extern int rpmatch (char const *response);
> 
> bool
> yesno (void)
> {
>-  /* We make some assumptions here:
>-     a) leading white space in the response are not vital
>-     b) the first 128 characters of the answer are enough (the rest can
>-	be ignored)
>-     I cannot think for a situation where this is not ok.  --drepper@gnu  */
>-  char buf[128];
>-  int len = 0;
>-  int c;
>-
>-  while ((c = getchar ()) != EOF && c != '\n')
>-    if ((len > 0 && len < 127) || (len == 0 && !isspace (c)))
>-      buf[len++] = c;
>-  buf[len] = '\0';
>+  char *response = NULL;
>+  size_t response_size = 0;
>+  ssize_t response_len = getline (&response, &response_size, stdin);
>+  bool yes;
>+
>+  if (response_len <= 0)
>+    yes = false;
>+  else
>+    {
>+      response[response_len - 1] = '\0';
>+      yes = (0 < rpmatch (response));
>+    }
> 
>-  return rpmatch (buf) == 1;
>+  free (response);
>+  return yes;
> }
>
>--
>
>  
>


Does this patch also fix the issue of arrow keys wrongly being enabled 
like a text editor (e.g. during "rm -i <blah>", a user can navigate 
through the screen.)


Thanks!

Best Regards,

Carlo

-- 
Carlo Florendo
Astra Philippines Inc.
www.astra.ph


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