lib/56967: Buggy implementation of strfmon()

[J.Zaitseff%zap.org.au@localhost]

>Number:         56967
>Category:       lib
>Synopsis:       Buggy implementation of strfmon()
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    lib-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Aug 17 03:00:00 +0000 2022
>Originator:     John Zaitseff
>Release:        9.3
>Organization:
The ZAP Group Australia
>Environment:
NetBSD vega-netbsd.home.zap.org.au 9.3 NetBSD 9.3 (GENERIC) #0: Thu Aug  4 15:30:37 UTC 2022  mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/amd64/compile/GENERIC amd64
>Description:
The implementation of strfmon() on NetBSD is unfortunately very buggy when grouping characters are involved.  The implementation used in FreeBSD seems to be free of these problems.
>How-To-Repeat:
Run the following on a NetBSD installation:

  $ wget -N https://www.zap.org.au/software/utils/scripts/strfmon.c
  $ cc -o strfmon strfmon.c

  $ ./strfmon 1234.56 en_US.UTF-8

The output on NetBSD is garbled:

  $1,234.5,234.56
  USD1,234.5,234.56

The output on FreeBSD is correct:

  $1,234.56
  USD 1,234.56

Furthermore, non-ASCII characters for the grouping character cause additional problems (truncated UTF-8 strings):

  $ ./strfmon 1234,56 ru_RU.UTF-8

gives, on NetBSD:

  1�234,5�234,56 руб.
  1�234,5�234,56 RUB

whereas FreeBSD gives the correct output:

  1 234,56 ₽
  1 234,56 RUB 

Note also that the correct local currency symbol for ru_RU.UTF-8 is "₽", not "руб." -- a separate bug in the locale data.
>Fix:
If possible, copy the latest version of <monetary.h>, strfmon() and strfmon_l() from FreeBSD.