sysread does not work on a filehandle to a scalar

[p5pRT]

Migrated from rt.perl.org#72428 (status was 'open')

Searchable as RT72428$

[p5pRT]

From jochen.perl@leahnim.org

Created by jochen.perl@leahnim.org

Testcase by ikegami​:

c​:\progs\perl580\bin\perl -le"$f='abc'; open $fh,'<',\$f or die; print read($fh,$b,2) ? $b : $!"
ab

c​:\progs\perl580\bin\perl -le"$f='abc'; open $fh,'<',\$f or die; print sysread($fh,$b,2) ? $b : $!"
Bad file descriptor

So using sysread on a filehandle to a scalar fails. While this may be somewhat expected
since obviously you can't call the system read function on such a "fake" filehandle, it
means it's not possible to pass a filehandle like that to a module that uses sysread.

It seems like this should be special-cased in sysread to make this work.

Perl Info

Flags:
    category=core
    severity=low

This perlbug was built using Perl v5.8.8 in the Red Hat build system.
It is being executed now by Perl v5.8.8 - Thu Aug 28 09:56:48 EDT 2008.

Site configuration information for perl v5.8.8:

Configured by Red Hat, Inc. at Thu Aug 28 09:56:48 EDT 2008.

Summary of my perl5 (revision 5 version 8 subversion 8) configuration:
  Platform:
    osname=linux, osvers=2.6.18-92.1.10.el5xen, archname=i386-linux-thread-multi
    uname='linux xenbuilder4.fedora.phx.redhat.com 2.6.18-92.1.10.el5xen #1 smp wed jul 23 04:11:52 edt 2008 i686 i686 i386 gnulinux '
    config_args='-des -Doptimize=-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m32 -march=i386 -mtune=generic -fasynchronous-unwind-tables -Dversion=5.8.8 -Dmyhostname=localhost -Dperladmin=root@localhost -Dcc=gcc -Dcf_by=Red Hat, Inc. -Dinstallprefix=/usr -Dprefix=/usr -Darchname=i386-linux -Dvendorprefix=/usr -Dsiteprefix=/usr -Duseshrplib -Dusethreads -Duseithreads -Duselargefiles -Dd_dosuid -Dd_semctl_semun -Di_db -Ui_ndbm -Di_gdbm -Di_shadow -Di_syslog -Dman3ext=3pm -Duseperlio -Dinstallusrbinperl=n -Ubincompat5005 -Uversiononly -Dpager=/usr/bin/less -isr -Dd_gethostent_r_proto -Ud_endhostent_r_proto -Ud_sethostent_r_proto -Ud_endprotoent_r_proto -Ud_setprotoent_r_proto -Ud_endservent_r_proto -Ud_setservent_r_proto -Dinc_version_list=5.8.7 5.8.6 5.8.5 -Dscriptdir=/usr/bin'
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=define use5005threads=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 ='-D_REENTRANT -D_GNU_SOURCE -fno-strict-aliasing -pipe -Wdeclaration-after-statement -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -I/usr/include/gdbm',
    optimize='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m32 -march=i386 -mtune=generic -fasynchronous-unwind-tables',
    cppflags='-D_REENTRANT -D_GNU_SOURCE -fno-strict-aliasing -pipe -Wdeclaration-after-statement -I/usr/local/include -I/usr/include/gdbm'
    ccversion='', gccversion='4.1.2 20070925 (Red Hat 4.1.2-33)', 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=4, prototype=define
  Linker and Libraries:
    ld='gcc', ldflags =' -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib
    libs=-lresolv -lnsl -lgdbm -ldb -ldl -lm -lcrypt -lutil -lpthread -lc
    perllibs=-lresolv -lnsl -ldl -lm -lcrypt -lutil -lpthread -lc
    libc=/lib/libc-2.7.so, so=so, useshrplib=true, libperl=libperl.so
    gnulibc_version='2.7'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E -Wl,-rpath,/usr/lib/perl5/5.8.8/i386-linux-thread-multi/CORE'
    cccdlflags='-fPIC', lddlflags='-shared -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m32 -march=i386 -mtune=generic -fasynchronous-unwind-tables -L/usr/local/lib'

Locally applied patches:
    


@INC for perl v5.8.8:
    /usr/lib/perl5/site_perl/5.8.8/i386-linux-thread-multi
    /usr/lib/perl5/site_perl/5.8.7/i386-linux-thread-multi
    /usr/lib/perl5/site_perl/5.8.6/i386-linux-thread-multi
    /usr/lib/perl5/site_perl/5.8.5/i386-linux-thread-multi
    /usr/lib/perl5/site_perl/5.8.8
    /usr/lib/perl5/site_perl/5.8.7
    /usr/lib/perl5/site_perl/5.8.6
    /usr/lib/perl5/site_perl/5.8.5
    /usr/lib/perl5/site_perl
    /usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi
    /usr/lib/perl5/vendor_perl/5.8.7/i386-linux-thread-multi
    /usr/lib/perl5/vendor_perl/5.8.6/i386-linux-thread-multi
    /usr/lib/perl5/vendor_perl/5.8.5/i386-linux-thread-multi
    /usr/lib/perl5/vendor_perl/5.8.8
    /usr/lib/perl5/vendor_perl/5.8.7
    /usr/lib/perl5/vendor_perl/5.8.6
    /usr/lib/perl5/vendor_perl/5.8.5
    /usr/lib/perl5/vendor_perl
    /usr/lib/perl5/5.8.8/i386-linux-thread-multi
    /usr/lib/perl5/5.8.8
    .


Environment for perl v5.8.8:
    HOME=/home/jochen
    LANG=en_US.UTF-8
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/sbin:/usr/sbin:/usr/kerberos/bin:/usr/local/bin:/bin:/usr/bin:/usr/games:/usr/games
    PERL_BADLANG (unset)
    SHELL=/bin/bash

[p5pRT]

From @chorny

Same results in latest blead (v5.11.4-43-g5e58db1*).

Feb 02 00​:30​:51 2010, jochen.perl@​leahnim.org wrote​:

c​:\progs\perl580\bin\perl -le"$f='abc'; open $fh,'<',\$f or die;
print read($fh,$b,2) ? $b : $!"
ab

c​:\progs\perl580\bin\perl -le"$f='abc'; open $fh,'<',\$f or die;
print sysread($fh,$b,2) ? $b : $!"
Bad file descriptor

--
Alexandr Ciornii, http​://chorny.net

[p5pRT]

From [Unknown Contact. See original ticket]

Same results in latest blead (v5.11.4-43-g5e58db1*).

Feb 02 00​:30​:51 2010, jochen.perl@​leahnim.org wrote​:

c​:\progs\perl580\bin\perl -le"$f='abc'; open $fh,'<',\$f or die;
print read($fh,$b,2) ? $b : $!"
ab

c​:\progs\perl580\bin\perl -le"$f='abc'; open $fh,'<',\$f or die;
print sysread($fh,$b,2) ? $b : $!"
Bad file descriptor

--
Alexandr Ciornii, http​://chorny.net

[p5pRT]

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