bug#73307: closed (Fix ctype(3) usage)

[GNU bug Tracking System]

Your message dated Tue, 17 Sep 2024 17:05:29 -0700
with message-id <89deb908-92a6-489f-bab9-116556ce8ce4@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.

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73307: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=73307
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--- Begin Message --- Subject: Fix ctype(3) usage Date: Mon, 16 Sep 2024 23:25:16 +0200

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
Description: Text Data

--- End Message ---

--- Begin Message --- Subject: Re: bug#73307: Fix ctype(3) usage Date: Tue, 17 Sep 2024 17:05:29 -0700 User-agent: Mozilla Thunderbird

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
Description: Text Data

0002-Fix-misuse-of-toupper-in-sfnt_parse_style.patch
Description: Text Data

0003-Fix-some-misparsing-in-check_interpreter.patch
Description: Text Data

0004-Use-c-ctype.h-in-lib-src.patch
Description: Text Data

--- End Message ---