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;
}
--