Win32 gethostbyaddr inconsistency on 'localhost'

[p5pRT]

Migrated from rt.perl.org#78364 (status was 'open')

Searchable as RT78364$

[p5pRT]

From @kmx

Created by @kmx

The following code​:

use Socket;
my $addr = gethostbyname('localhost');
my $name = gethostbyaddr($addr, AF_INET);
my $ip = inet_ntoa($addr);
print "name=$name\nip=$ip\n";

has according my tests different behaviour on MS Windows and Linux.

Output on MS Windows​:
name=MYPCNAME.domain.cz
ip=127.0.0.1

Output on Linux​:
name=localhost.localdomain
ip=127.0.0.1

I am not sure if this is intended behaviour; however I have a feeling that
it would have been more correct if the $name variable in my example had
returned something like 'localhost'.

SIDE NOTE1​: this issue makes troubles on Win32 when using HTTP​::Daemon like
this​:

use HTTP​::Daemon;
my $srv = HTTP​::Daemon->new(LocalAddr => 'localhost​:8080');
print "url=", $srv->url;

on Windows box the example above prints​:
url=http​://MYPCNAME.domain.cz​:8080/
however the daemon listens just on 127.0.0.1​:8080 so the $srv->url is invalid.

The trouble is that HTTP​::Daemon is calling gethostbyaddr() in a similar
way as I have shown in the first example.

SIDE NOTE2​: due to this HTTP​::Daemon issue installation of WWW​::Mechanize
on Win32 fails during its tests

Thanks in advance for any feedback.

--
kmx

Perl Info

Flags:
    category=library
    severity=low
    module=Socket

Site configuration information for perl 5.12.1:

Configured by 1 at Thu Jul 29 16:39:48 2010.

Summary of my perl5 (revision 5 version 12 subversion 1) configuration:
   
  Platform:
    osname=MSWin32, osvers=5.1, archname=MSWin32-x86-multi-thread
    uname='Win32 strawberryperl 5.12.1.0 #1 Thu Jul 29 10:08:11 2010 i386'
    config_args='undef'
    hint=recommended, useposix=true, d_sigaction=undef
    useithreads=define, usemultiplicity=define
    useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
    use64bitint=undef, use64bitall=undef, uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='gcc', ccflags =' -s -O2 -DWIN32 -DHAVE_DES_FCRYPT 
-DUSE_SITECUSTOMIZE -DPERL_IMPLICIT_CONTEXT -DPERL_IMPLICIT_SYS
-fno-strict-aliasing -mms-bitfields -DPERL_MSVCRT_READFIX',
    optimize='-s -O2',
    cppflags='-DWIN32'
    ccversion='', gccversion='4.4.3', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
    d_longlong=undef, longlongsize=8, d_longdbl=define, longdblsize=12
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='long long',
lseeksize=8
    alignbytes=8, prototype=define
  Linker and Libraries:
    ld='g++', ldflags ='-s -L"D:\strawberry32\perl\lib\CORE"
-L"D:\strawberry32\c\lib"'
    libpth=D:\strawberry32\c\lib D:\strawberry32\c\i686-w64-mingw32\lib
    libs=-lmoldname -lkernel32 -luser32 -lgdi32 -lwinspool -lcomdlg32
-ladvapi32 -lshell32 -lole32 -loleaut32 -lnetapi32 -luuid -lws2_32 -lmpr
-lwinmm -lversion -lodbc32 -lodbccp32 -lcomctl32
    perllibs=-lmoldname -lkernel32 -luser32 -lgdi32 -lwinspool -lcomdlg32
-ladvapi32 -lshell32 -lole32 -loleaut32 -lnetapi32 -luuid -lws2_32 -lmpr
-lwinmm -lversion -lodbc32 -lodbccp32 -lcomctl32
    libc=, so=dll, useshrplib=true, libperl=libperl512.a
    gnulibc_version=''
  Dynamic Linking:
    dlsrc=dl_win32.xs, dlext=dll, d_dlsymun=undef, ccdlflags=' '
    cccdlflags=' ', lddlflags='-mdll -s -L"D:\strawberry32\perl\lib\CORE"
-L"D:\strawberry32\c\lib"'

Locally applied patches:
    


@INC for perl 5.12.1:
    D:/strawberry32/perl/site/lib
    D:/strawberry32/perl/vendor/lib
    D:/strawberry32/perl/lib
    .


Environment for perl 5.12.1:
    HOME=C:\Users\kmx
    LANG (unset)
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
   
PATH=D:\strawberry32\\perl\site\bin;D:\strawberry32\\perl\bin;D:\strawberry32\\c\bin;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem
    PERL_BADLANG (unset)
    PERL_MM_USE_DEFAULT=1
    SHELL (unset)

[p5pRT]

@khwilliamson - Status changed from 'new' to 'open'

[richardleach]

By Strawberry Perl v5.30.0 on Win 10:

• WWW::Mechanize installs okay, passing all tests that it hasn't skipped
• HTTP::Daemon also installs okay (looked like it did anyway, but FYI)
• running the "SIDE NOTE1" code results in a URL containing the localhost IP address (IPv6 in this case), rather than the FQDN for the host:

C:\fldr>perl sidenote1.pl
url=http://[::1]:8080/

@kmx - are you happy with the current behaviour or is there still something to be done?