minor test failures on Alpine linux (linux kernel + musl libc + busybox utils)

[Assaf Gordon]

Hello,

I'm experimenting with testing coreutils on Alpine Linux ( 
https://alpinelinux.org/ ).
Alpine is a lightweight Linux-based system, with musl libc and busybox 
utilities - so not very GNU-like, and possibly not POSIX compliant.
These minor failures are obviously not a priority, but I suspect such systems 
will become more common in the future (due to usage in small VMs / containers). 
Most of them are problems with the tests, not with the programs.

I'll provide brief notes here, with more details in the attachments.

The failures are:
 FAIL: tests/ln/sf-1.sh
 FAIL: tests/misc/help-version.sh
 FAIL: tests/misc/sort-debug-warn.sh
 FAIL: tests/misc/wc-files0.sh

=== tests/misc/help-version.sh ===

This fails because musk-libc disables the UTMP mechanism on purpose:
  
http://wiki.musl-libc.org/wiki/FAQ#Q:_why_is_the_utmp.2Fwtmp_functionality_only_implemented_as_stubs_.3F

The file 'utmp.h' contains:
  $ cat /usr/include/utmp.h
  [...]
  #define _PATH_UTMP "/dev/null/utmp"
  #define _PATH_WTMP "/dev/null/wtmp"
  #define UTMP_FILE _PATH_UTMP
  #define WTMP_FILE _PATH_WTMP
  #define UTMP_FILENAME _PATH_UTMP
  #define WTMP_FILENAME _PATH_WTMP

which means that 'readutmp.m4' passes all the normal detection checks, but the 
compiled 'pinky' and 'who' use the hard-coded (and non-existing) file:
   $ ./src/pinky
   ./src/pinky: /dev/null/utmp: Not a directory
   $ ./src/who
   ./src/who: /dev/null/utmp: Not a directory

Perhaps additional checks be made in 'readutmp.m4', or alternatively skip 
'pinky' tests if the file is invalid?



=== tests/ln/sf-1.sh ===

fails because of (non-portable?) printf usage:

    + printf %0*d 256 0
    ash: %0*d: invalid format

The attached patch replaces the printf usage into a more portable one.
(an alternative would be to use 'env printf' invoking coreutils' printf, but 
other tests use the built-in printf with embedded "%${size}d" syntax).

regarding the portability of "*" in printf, the POSIX page says:
http://pubs.opengroup.org/onlinepubs/9699919799/utilities/printf.html

  APPLICATION USAGE
  [..]
  No provision is made in this volume of POSIX.1-2008 which allows field widths 
and precisions to 
  be specified as '*' since the '*' can be replaced directly in the format 
operand using shell
  variable substitution. Implementations can also provide this feature as an 
extension if they so choose.





=== tests/misc/wc-files0.sh ===

This fails because the "expected" output file is generated using the $'\t' 
syntax,
and it seems BusyBox ash does not support it (if I read the log correctly):

The test script has:

   printf '%s\n' "0 0 0 '1'$'\\n''2'" > exp || framework_failure_

And the failure log has:

   + diff -u exp out
   --- exp
   +++ out
   @@ -1 +1 @@
   -0 0 0 '1''\n''2'
   +0 0 0 '1'$'\n''2'
   + fail=1

The attached 'alp-bug-shell-dollar-sign.txt' gives example of the syntax on few 
shells, it seems ASH is the exception.



=== tests/misc/sort-debug-warn.sh ===

The failure is in the last debug message.
The expected message is for an invalid forced locale, but musl-libc seems to 
accept the invalid locale:

   + diff -u exp out
   --- exp
   +++ out
   @@ -29,4 +29,4 @@
    sort: using simple byte comparison
    sort: using simple byte comparison
    sort: using simple byte comparison
   -sort: failed to set locale; using simple byte comparison
   +sort: using ‘missing’ sorting rules
   + fail=1

The flow is:
1. 'LC_ALL=missing sort --debug ...' calls 'hard_locale()'
2. most libc implementations return 'C' for invalid locales, thus 'hard_locale' 
returns false.
3. musl-libc implementation return 'missing' and 'hard_locale' returns true.
4. the incorrect debug message is printed.

The attached 'alp-bug-LC-ALL-missing.txt' contains a tiny C program to 
demonstrate this, with results from several libc implementations.



Comments welcomed. I'm happy to test things further if needed.

regards,
 - assaf

0001-tests-avoid-non-portable-printf.patch
Description: Binary data

alp-bug-LC-ALL-missing.txt
Description: Text document

alp-bug-shell-dollar-sign.txt
Description: Text document

alpine-test-suite.log.xz
Description: Binary data