GNU bug report logs - #73307
Fix ctype(3) usage

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From: help-debbugs <at> gnu.org (GNU bug Tracking System)
To: Paul Eggert <eggert <at> cs.ucla.edu>
Cc: tracker <at> debbugs.gnu.org
Subject: bug#73307: closed (Fix ctype(3) usage)
Date: Wed, 18 Sep 2024 00:06:01 +0000

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Your message dated Tue, 17 Sep 2024 17:05:29 -0700
with message-id <89deb908-92a6-489f-bab9-116556ce8ce4 <at> cs.ucla.edu>
and subject line Re: bug#73307: Fix ctype(3) usage
has caused the debbugs.gnu.org bug report #73307,
regarding Fix ctype(3) usage
to be marked as done.

(If you believe you have received this mail in error, please contact
help-debbugs <at> gnu.org.)


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From: Thomas Klausner <wiz <at> gatalith.at>
To: bug-gnu-emacs <at> gnu.org
Subject: Fix ctype(3) usage
Date: Mon, 16 Sep 2024 23:25:16 +0200

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Tags: patch


When compiling emacs on NetBSD-10.99.12/amd64, I get the following
warning

In file included from /usr/include/ctype.h:100,
                 from fns.c:29:
fns.c: In function 'Fyes_or_no_p':
fns.c:3582:33: warning: array subscript has type 'char' [-Wchar-subscripts]
 3582 |     if ((len > 0) && !isspace (s[len - 1]))
      |                                 ^

The NetBSD man page for ctype(3): https://man.netbsd.org/ctype.3
is quite explicit about the problems with this - ctype(3) functions only
accept -1 and "unsigned char" and you can get very weird problems if
this is disregarded.

The attached patch adds the missing cast.


In GNU Emacs 31.0.50 (build 1, x86_64--netbsd, GTK+ Version 3.24.43,
 cairo version 1.18.0) of 2024-09-16
Repository revision: f27553c30a772a0103d2e6762e4d7f588f302e4b
Repository branch: HEAD
System Description: NetBSD 10.99.12/amd64

Configured using:
 'configure --srcdir=/scratch/wip/emacs-git/work/emacs
 --localstatedir=/var --with-native-compilation --without-ns
 --without-imagemagick --without-xaw3d --with-x-toolkit=gtk3
 --prefix=/usr/pkg --build=x86_64--netbsd --host=x86_64--netbsd
 --infodir=/usr/pkg/info --mandir=/usr/pkg/man
 --enable-option-checking=yes 'CFLAGS=-O2 -g -g -fstack-clash-protection
 -I/usr/pkg/include -I/usr/include -I/usr/pkg/include/freetype2
 -I/usr/pkg/include/glib-2.0 -I/usr/pkg/include/gio-unix-2.0
 -I/usr/pkg/lib/glib-2.0/include -I/usr/pkg/include/harfbuzz
 -I/usr/pkg/include/libdrm' 'CPPFLAGS=-g -I/usr/pkg/include
 -I/usr/include -I/usr/pkg/include/freetype2 -I/usr/pkg/include/glib-2.0
 -I/usr/pkg/include/gio-unix-2.0 -I/usr/pkg/lib/glib-2.0/include
 -I/usr/pkg/include/harfbuzz -I/usr/pkg/include/libdrm'
 'LDFLAGS=-Wl,-R/usr/pkg/gcc14/lib -Wl,-zrelro -Wl,-znow -L/usr/pkg/lib
 -Wl,-R/usr/pkg/lib -L/usr/lib -Wl,-R/usr/lib''

[patch-src_fns.c (text/x-c, attachment)]

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From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: Po Lu <luangruo <at> yahoo.com>, 73307-done <at> debbugs.gnu.org,
 Thomas Klausner <wiz <at> gatalith.at>
Subject: Re: bug#73307: Fix ctype(3) usage
Date: Tue, 17 Sep 2024 17:05:29 -0700

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On 2024-09-17 04:52, Eli Zaretskii wrote:
> However, I'm not sure this is the right fix, the function is
> defined with argument type of 'int'.  Paul, any comments?

Although that patch was an improvement it still had problems, as it 
incorrectly assumed the string does not end in a multibyte space, and 
that Emacs's locale matches the system's.

Emacs itself should not use <ctype.h> unless it knows the string is 
unibyte and the system locale matches Emacs's. I scanned through its 
source code looking for all problematic instances of <ctype.h> that have 
crept in (except I didn't scan the MS-Windows code, where you're the 
expert), and found five other places where ctype.h was obviously 
misused. I installed the attached to fix these glitches and am boldly 
closing this the report.

I can't easily test patch 0003, which fixes Android-specific code. 
Although I think it's an improvement, in unlikely cases I suspect it 
still doesn't exactly match what the Android kernel does with #! lines. 
I don't know whether that matters. I'll CC this to Po Lu (my goto person 
for Android) as a heads-up.

[0001-Fix-yes-or-no-p-with-multibyte-spaces.patch (text/x-patch, attachment)]

[0002-Fix-misuse-of-toupper-in-sfnt_parse_style.patch (text/x-patch, attachment)]

[0003-Fix-some-misparsing-in-check_interpreter.patch (text/x-patch, attachment)]

[0004-Use-c-ctype.h-in-lib-src.patch (text/x-patch, attachment)]

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