Failure to compile on Alpine linux due to undefined mempcpy

[brassy-endomorph]

Running pip install libpff-python-ratom (which I know isn't something you maintain, but you're upstream) results in this error:

    gcc -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -DTHREAD_STACK_SIZE=0x100000 -fPIC -DHAVE_CONFIG_H= -DLOCALEDIR="/usr/share/locale" -Iinclude -Icommon -Ilibcerror -Ilibcthreads -Ilibcdata -Ilibclocale -Ilibcnotify -Ilibcsplit -Ilibuna -Ilibcfile -Ilibcpath -Ilibbfio -Ilibfcache -Ilibfdata -Ilibfdatetime -Ilibfguid -Ilibfvalue -Ilibfwnt -Ilibfmapi -Ilibpff -I/usr/local/include/python3.10 -c pypff/pypff_attachment.c -o build/temp.linux-x86_64-3.10/pypff/pypff_attachment.o
    In file included from /usr/include/fortify/strings.h:22,
                     from /usr/include/string.h:57,
                     from /usr/include/fortify/wchar.h:30,
                     from include/libpff/types.h:193,
                     from common/types.h:34,
                     from pypff/pypff_attachment.c:23:
    /usr/include/fortify/string.h:144:1: error: 'mempcpy' undeclared here (not in a function); did you mean 'memccpy'?
      144 | _FORTIFY_FN(mempcpy) void *mempcpy(void *__d, const void *__s, size_t __n)
          | ^~~~~~~~~~~
    In file included from /usr/local/include/python3.10/Python.h:30,
                     from pypff/pypff_python.h:46,
                     from pypff/pypff_item.h:29,
                     from pypff/pypff_attachment.h:28,
                     from pypff/pypff_attachment.c:30:
    /usr/include/fortify/string.h: In function 'mempcpy':
    /usr/include/fortify/string.h:151:9: error: called object '__orig_mempcpy' is not a function or function pointer
      151 |  return __orig_mempcpy(__d, __s, __n);
          |         ^~~~~~~~~~~~~~
    In file included from /usr/include/fortify/strings.h:22,
                     from /usr/include/string.h:57,
                     from /usr/include/fortify/wchar.h:30,
                     from include/libpff/types.h:193,
                     from common/types.h:34,
                     from pypff/pypff_attachment.c:23:
    /usr/include/fortify/string.h:144:1: note: declared here
      144 | _FORTIFY_FN(mempcpy) void *mempcpy(void *__d, const void *__s, size_t __n)
          | ^~~~~~~~~~~
    error: command '/usr/bin/gcc' failed with exit code 1
    ----------------------------------------

This appears to be related to this: python-pillow/Pillow#1850

Env:

• Alpine 3.15
• Python 3.10.2
• libpff-python-ratom 20200808

[joachimmetz]

1. Python bindings are not officially completed Add Python bindings #2
2. libpff/pypff codebase doesn't use mempcpy

So this is not a libpff/pypff issue

[joachimmetz]

Based on the links you refer to this seems to be a missing define of GNU_SOURCE in the Alpine Python build configuration/environment.

[brassy-endomorph]

It may not, but the order of includes within the codebase may be causing that in a similar manner to this comment here. python-pillow/Pillow#1850 (comment)

[joachimmetz]

https://github.com/libyal/libpff/blob/main/include/libpff/types.h.in#L193 just imports wchar.h of libc stdlib

Alpine Linux seems to ship a "fortify" version of this header, this is where the error happens

setup.py uses python-config --cflags to determine the compile flags, check if that sets GNU_SOURCE on Alpine Linux