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[perl #114608] FILE* typemap screw up filehandles

From:
Leon Timmermans
Date:
August 27, 2012 08:28
Subject:
[perl #114608] FILE* typemap screw up filehandles
Message ID:
rt-3.6.HEAD-11172-1346081302-1532.114608-75-0@perl.org
# New Ticket Created by  Leon Timmermans 
# Please include the string:  [perl #114608]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org:443/rt3/Ticket/Display.html?id=114608 >


This is a bug report for perl from fawaka@gmail.com,
generated with the help of perlbug 1.39 running under perl 5.16.1.

-----------------------------------------------------------------

The XS Typemap file FILE* pushes a :stdio layer on top of the
filehandle but never removes it, carpeting over the existing layers.
This is particularly troublesome with encoding layers. For example
(this uses Sys::Mmap, but any module using the FILE* typemap should
give the same result):

$ perl -MSys::Mmap -E 'open my $fh, "<:encoding(utf-8)", "Changes";
say join ":", PerlIO::get_layers($fh); mmap my $var, -s $fh,
PROT__READ, MAP_SHARED, $fh, 0; say join ":", PerlIO::get_layers($fh)'
unix:perlio:encoding(utf-8-strict):utf8
unix:perlio:encoding(utf-8-strict):utf8:stdio

The latter is effectively the same as just «stdio» (until a
PerlIO_releaseFILE/PerlIO_pop). A conversion should never result in a
variable changing in nature or lose data, this is plain wrong.

-----------------------------------------------------------------
---
Flags:
    category=core
    severity=low
---
Site configuration information for perl 5.16.1:

Configured by leon at Thu Aug  9 12:30:13 EEST 2012.

Summary of my perl5 (revision 5 version 16 subversion 1) configuration:

  Platform:
    osname=linux, osvers=3.2.0-27-generic, archname=x86_64-linux-thread-multi
    uname='linux leon-laptop 3.2.0-27-generic #43-ubuntu smp fri jul 6
14:25:57 utc 2012 x86_64 x86_64 x86_64 gnulinux '
    config_args='-de
-Dprefix=/home/leon/perl5/perlbrew/perls/perl-5.16.1 -Duseshrplib
-Dusethreads'
    hint=recommended, useposix=true, d_sigaction=define
    useithreads=define, usemultiplicity=define
    useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
    use64bitint=define, use64bitall=define, uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -fno-strict-aliasing
-pipe -fstack-protector -I/usr/local/include -D_LARGEFILE_SOURCE
-D_FILE_OFFSET_BITS=64',
    optimize='-O2',
    cppflags='-D_REENTRANT -D_GNU_SOURCE -fno-strict-aliasing -pipe
-fstack-protector -I/usr/local/include'
    ccversion='', gccversion='4.6.3', gccosandvers=''
    intsize=4, longsize=8, ptrsize=8, doublesize=8, byteorder=12345678
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
    ivtype='long', ivsize=8, nvtype='double', nvsize=8, Off_t='off_t',
lseeksize=8
    alignbytes=8, prototype=define
  Linker and Libraries:
    ld='cc', ldflags =' -fstack-protector -L/usr/local/lib'
    libpth=/usr/local/lib /lib/x86_64-linux-gnu /lib/../lib
/usr/lib/x86_64-linux-gnu /usr/lib/../lib /lib /usr/lib
    libs=-lnsl -ldb -ldl -lm -lcrypt -lutil -lpthread -lc
    perllibs=-lnsl -ldl -lm -lcrypt -lutil -lpthread -lc
    libc=, so=so, useshrplib=true, libperl=libperl.so
    gnulibc_version='2.15'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E
-Wl,-rpath,/home/leon/perl5/perlbrew/perls/perl-5.16.1/lib/5.16.1/x86_64-linux-thread-multi/CORE'
    cccdlflags='-fPIC', lddlflags='-shared -O2 -L/usr/local/lib
-fstack-protector'

Locally applied patches:


---
@INC for perl 5.16.1:
    /home/leon/perl5/perlbrew/perls/perl-5.16.1/lib/site_perl/5.16.1/x86_64-linux-thread-multi
    /home/leon/perl5/perlbrew/perls/perl-5.16.1/lib/site_perl/5.16.1
    /home/leon/perl5/perlbrew/perls/perl-5.16.1/lib/5.16.1/x86_64-linux-thread-multi
    /home/leon/perl5/perlbrew/perls/perl-5.16.1/lib/5.16.1
    .

---
Environment for perl 5.16.1:
    HOME=/home/leon
    LANG=en_US.UTF-8
    LANGUAGE=en_US:en
    LC_ADDRESS=en_US.UTF-8
    LC_IDENTIFICATION=en_US.UTF-8
    LC_MEASUREMENT=en_US.UTF-8
    LC_MONETARY=en_US.UTF-8
    LC_NAME=en_US.UTF-8
    LC_NUMERIC=en_US.UTF-8
    LC_PAPER=en_US.UTF-8
    LC_TELEPHONE=en_US.UTF-8
    LC_TIME=en_US.UTF-8
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/home/leon/perl5/perlbrew/bin:/home/leon/perl5/perlbrew/perls/perl-5.16.1/bin:/home/leon/bin:/usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
    PERLBREW_HOME=/home/leon/.perlbrew
    PERLBREW_PATH=/home/leon/perl5/perlbrew/bin:/home/leon/perl5/perlbrew/perls/perl-5.16.1/bin
    PERLBREW_PERL=perl-5.16.1
    PERLBREW_ROOT=/home/leon/perl5/perlbrew
    PERLBREW_VERSION=0.25
    PERL_BADLANG (unset)
    SHELL=/bin/bash




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