HTTP/2 200 cache-control: max-age=43200 server: Combust/Plack (Perl) vary: Accept-Encoding content-encoding: gzip content-length: 3133 content-type: text/html; charset=utf-8 last-modified: Sat, 11 Oct 2025 15:51:26 GMT date: Sat, 11 Oct 2025 15:51:26 GMT strict-transport-security: max-age=15768000 Front page | perl.perl5.porters | Postings from July 2008

[perl #56644] PerlIO resource leaks on open() and then :pop in :unix and :stdio

Thread Next

# New Ticket Created by  "Goro Fuji" 
# Please include the string:  [perl #56644]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org/rt3/Ticket/Display.html?id=56644 >
This is a bug report for perl from garo@goro.nonet,
generated with the help of perlbug 1.36 running under perl 5.10.0.
-----------------------------------------------------------------
Hi, perl5porters.
I found some problems in perlio.c; please see and try the following:
#!perl
my $file = '/dev/null'; # it doesn't matter
for(1 .. 10){
	open my $fh, '<:unix', $file;
	print fileno($in), "\n";
	binmode $fh, ':pop';
}
__END__
It leads to resource leaks when :unix and :stdio are used.
The :pop pseudo layer invokes a destructor Popped() of the vtable, and
the destructor should release their resources. However, the :unix and
:stdio layers
do nothing on Popped(). They release their resources only when their
Close() is called.
(Moreover, PerlIOMmap_close() is defined in perlio.c, but it is not
used anywhere, although it may be harmless. I think these issues come
from a bad design of PerlIO virtual table; there are two kind of
destructors, Popped() and Close(), which may confuse the PerlIO
authors. Actually, only Popped() might be required.)
The "ioleaks.diff" solves these problems, and "ioleaks.t" is its tests.
P.S.
I also found a trivial mistake in perliol.pod. See the "perliol.diff".
-----------------------------------------------------------------
---
Flags:
    category=core
    severity=low
---
Site configuration information for perl 5.10.0:
Configured by garo at Sun Jan  6 08:39:07 JST 2008.
Summary of my perl5 (revision 5 version 10 subversion 0) configuration:
  Platform:
    osname=cygwin, osvers=1.5.25(0.15642), archname=cygwin-thread-multi
    uname='cygwin_nt-5.1 goro 1.5.25(0.15642) 2007-12-14 19:21 i686 cygwin '
    config_args='-de -Dmksymlnks -Doptimize=-O3 -Dusethreads
-Acccdlflags=-s -Alddlflags=-s -Accdlflags=-s -Dman3ext=3pm'
    hint=recommended, useposix=true, d_sigaction=define
    useithreads=define, usemultiplicity=define
    useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
    use64bitint=undef, use64bitall=undef, uselongdouble=undef
    usemymalloc=y, bincompat5005=undef
  Compiler:
    cc='gcc', ccflags ='-DPERL_USE_SAFE_PUTENV -U__STRICT_ANSI__
-fno-strict-aliasing -pipe -Wall -Wextra -Wmissing-prototypes
-Winit-self',
    optimize='-O3',
    cppflags='-DPERL_USE_SAFE_PUTENV -U__STRICT_ANSI__
-fno-strict-aliasing -pipe'
    ccversion='', gccversion='3.4.4 (cygming special, gdc 0.12, using
dmd 0.125)', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t',
lseeksize=8
    alignbytes=8, prototype=define
  Linker and Libraries:
    ld='g++', ldflags =' -Wl,--enable-auto-import
-Wl,--export-all-symbols -Wl,--stack,8388608
-Wl,--enable-auto-image-base -Wl,--enable-auto-import
-L/usr/local/lib'
    libpth=/usr/local/lib /usr/lib /lib
    libs=-ldl -lcrypt
    perllibs=-ldl -lcrypt
    libc=/usr/lib/libc.a, so=dll, useshrplib=true, libperl=libperl.a
    gnulibc_version=''
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=dll, d_dlsymun=undef, ccdlflags=' -s'
    cccdlflags='  -s', lddlflags=' --shared  -Wl,--enable-auto-import
-Wl,--export-all-symbols -Wl,--stack,8388608
-Wl,--enable-auto-image-base -Wl,--enable-auto-import -s
-L/usr/local/lib'
Locally applied patches:
---
@INC for perl 5.10.0:
    /usr/local/lib/perl5/5.10.0/cygwin-thread-multi
    /usr/local/lib/perl5/5.10.0
    /usr/local/lib/perl5/site_perl/5.10.0/cygwin-thread-multi
    /usr/local/lib/perl5/site_perl/5.10.0
    .
---
Environment for perl 5.10.0:
    HOME=/home/garo
    LANG (unset)
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/usr/local/parrot/bin:/usr/local/bin:/usr/bin:/bin:/usr/X11R6/bin:/usr/local/bin:/cygdrive/c/Program
Files/Microsoft Visual Studio 8/Common7/IDE:/cygdrive/c/Program
Files/Microsoft Visual Studio 8/VC/BIN:/cygdrive/c/Program
Files/Microsoft Visual Studio 8/Common7/Tools:/cygdrive/c/Program
Files/Microsoft Visual Studio 8/Common7/Tools/bin:/cygdrive/c/Program
Files/Microsoft Visual Studio 8/VC/PlatformSDK/bin:/cygdrive/c/Program
Files/Microsoft Visual Studio
8/SDK/v2.0/bin:/cygdrive/c/WINDOWS/Microsoft.NET/Framework/v2.0.50727:/cygdrive/c/Program
Files/Microsoft Visual Studio 8/VC/VCPackages:/cygdrive/c/program
files/imagemagick-6.2.8-q16:/cygdrive/c/ActivePerl5.10/bin:/cygdrive/c/WINDOWS/system32:/cygdrive/c/WINDOWS:/cygdrive/c/WINDOWS/System32/Wbem:/cygdrive/c/Program
Files/ATI Technologies/ATI Control Panel:/cygdrive/c/Program
Files/Microsoft SQL
Server/90/Tools/binn/:/cygdrive/c/PROGRA~1/IBM/IBMHOM~1.04/Outloud:/cygdrive/c/Program
Files/QuickTime/QTSystem/:/cygdrive/c/Program Files/Microsoft Visual
Studio 8/VC/bin:/cygdrive/c/Program Files/R/bin:/cygdrive/c/program
files/imagemagick-6.2.8-q16:/cygdrive/c/ActivePerl5.10/bin:/cygdrive/c/WINDOWS/system32:/cygdrive/c/WINDOWS:/cygdrive/c/WINDOWS/System32/Wbem:/cygdrive/c/Program
Files/ATI Technologies/ATI Control Panel:/cygdrive/c/Program
Files/Microsoft SQL
Server/90/Tools/binn/:/cygdrive/c/PROGRA~1/IBM/IBMHOM~1.04/Outloud:/cygdrive/c/Program
Files/QuickTime/QTSystem/
    PERLIO=:perlio
    PERL_BADLANG (unset)
    SHELL (unset)

Thread Next

• [perl #56644] PerlIO resource leaks on open() and then :pop in :unix and :stdio by Goro Fuji
• Re: [perl #56644] PerlIO resource leaks on open() and then :pop in :unix and :stdio by Goro Fuji