Subject: 28.1; Compilation failure for lib-src/seccomp-filter.c on x86_64 with 32 bit userspace

From: Ulrich Mueller <[email-masked]>
Date: Thu, 14 Jul 2022 08:46:25 +0200

Forwarding Gentoo bug https://bugs.gentoo.org/857906:

i686-pc-linux-gnu-gcc     -I. -I../src -I../lib -I. -I./../src -I./../lib  -Wl,-O1 -Wl,--as-needed  -mtune=i686 -O2 -pipe  seccomp-filter.c \                           
  -lseccomp  -o seccomp-filter                                                                                                                                          
In file included from seccomp-filter.c:62:                                                                                                                              
seccomp-filter.c: In function 'main':                                                                                                                                   
../lib/verify.h:213:41: error: static assertion failed: "verify (sizeof (long) == 8 && LONG_MIN == INT64_MIN && LONG_MAX == INT64_MAX)"                                 
  213 | # define _GL_VERIFY(R, DIAGNOSTIC, ...) _Static_assert (R, DIAGNOSTIC)                                                                                          
      |                                         ^~~~~~~~~~~~~~                                                                                                          
../lib/verify.h:273:20: note: in expansion of macro '_GL_VERIFY'                                                                                                        
  273 | # define verify(R) _GL_VERIFY (R, "verify (" #R ")", -)                                                                                                         
      |                    ^~~~~~~~~~                                                                                                                                   
seccomp-filter.c:173:3: note: in expansion of macro 'verify'                                                                                                            
  173 |   verify (sizeof (long) == 8 && LONG_MIN == INT64_MIN                                                                                                           
      |   ^~~~~~                                                                                                                                                        
../lib/verify.h:213:41: error: static assertion failed: "verify (sizeof (void *) == 8)"                                                                                 
  213 | # define _GL_VERIFY(R, DIAGNOSTIC, ...) _Static_assert (R, DIAGNOSTIC)                                                                                          
      |                                         ^~~~~~~~~~~~~~
...
seccomp-filter.c:175:3: note: in expansion of macro 'verify'                                                                                                            
  175 |   verify (sizeof (void *) == 8);                                                                                                                                
      |   ^~~~~~                                                                                                                                                        
make[1]: *** [Makefile:435: seccomp-filter] Error 1                                                                                                                     
make[1]: *** Waiting for unfinished jobs....                                                                                                                            
make[1]: Leaving directory '/var/tmp/portage/app-editors/emacs-28.1/work/emacs-28.1/lib-src'                                                                            
make: *** [Makefile:436: lib-src] Error 2

This is on an x86_64 machine with 32 bit userspace.

AFAICS, the problem is that lib-src/seccomp-filter.c (line 173) tests
for a 64 bit userspace:

  verify (sizeof (long) == 8 && LONG_MIN == INT64_MIN
          && LONG_MAX == INT64_MAX);

However, lib_src/Makefile.in (line 203) tests for 64 bit hardware:

ifeq ($(shell uname -m),x86_64)
[...]
SECCOMP_FILTER=1
endif