abs_path() errouneously returning undef because lstat() sets errno to EINVAL

p5pRT commented 13 years ago

Migrated from rt.perl.org#84338 (status was 'resolved')

Searchable as RT84338$

p5pRT commented 13 years ago

From dmuey@cpan.org

Created by dmuey@cpan.org

Hello\,

I am seeing several systems behaving strangely (details below) in regards to abs_path. I am still tracing this out and wanted to post the details for reference and in case one of you gurus see what the cause could be right off hand\, thanks!

[ -- Working server -- ]

# perl -MCwd -Mstrict -wle 'my $etc = Cwd::abs_path("/etc");if (defined $etc) { print "Defined: $etc" } else { print "Undefined"; }' Defined: /etc

[ -- Affected server -- ]

# perl -MCwd -Mstrict -wle 'my $etc = Cwd::abs_path("/etc");if (defined $etc) { print "Defined: $etc" } else { print "Undefined"; }' Undefined

[ -- lower level -- ]

If I add debug output before and after line 156 in Cwd.xs like so:

printf("DEBUG Before %d %s\n"\, errno\, resolved); struct stat sb; if (lstat(resolved\, &sb) != 0) { printf("DEBUG After %d %s\n"\, errno\, resolved); if (errno == ENOENT && p == NULL) { errno = serrno; return (resolved); } return (NULL); } printf("DEBUG I got past the return(NULL) above");

and rebuild it\, then we now see that errno was changed from ENOENT to EINVAL and thus the return(NULL) is triggered:

# perl -I. -I./blib/arch -MCwd -Mstrict -wle 'my $etc = Cwd::abs_path("/etc");if (defined $etc) { print "Defined: $etc" } else { print "Undefined"; }' DEBUG Before 2 /etc DEBUG After 22 /etc Undefined

It is the same if we change lstat() to PerlLIO_lstat()

[ -- misc info -- ]

Both servers are • 64 bit • CentOS release 5.5 (Final) • Using Cwd 3.33 (but installing older version results in the same behavior) • have “d_lstat” set to “define”

Working server: • This is perl\, v5.8.8 built for x86_64-linux • from RPM: perl.x86_64 4:5.8.8-32.el5_5.2 (another affected server had perl.x86_64 4:5.8.8-27.el5 installed)

Affected server (the server this perlbug was sent from): • This is perl\, v5.8.8 built for x86_64-linux-thread-multi • from RPM: perl.x86_64 4:5.8.8-32.el5_5.1 (another affected server had perl.x86_64 4:5.8.8-27.el5 installed)

A diff of the output of:

perl -MConfig -e 'for $k (sort keys %Config) { print "$k:$Config{$k}\n"; }'

on each box is attached to https://rt.cpan.org/Ticket/Display.html?id=65379

Perl Info

``` Flags: category=library severity=high 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 - Mon Jun 7 21:25:07 EDT 2010. Site configuration information for perl v5.8.8: Configured by Red Hat, Inc. at Mon Jun 7 21:25:07 EDT 2010. Summary of my perl5 (revision 5 version 8 subversion 8) configuration: Platform: osname=linux, osvers=2.6.18-53.el5, archname=x86_64-linux-thread-multi uname='linux builder10.centos.org 2.6.18-53.el5 #1 smp mon nov 12 02:14:55 est 2007 x86_64 x86_64 x86_64 gnulinux ' config_args='-des -Doptimize=-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic -Dversion=5.8.8 -Dmyhostname=localhost -Dperladmin=root@localhost -Dcc=gcc -Dcf_by=Red Hat, Inc. -Dinstallprefix=/usr -Dprefix=/usr -Dlibpth=/usr/local/lib64 /lib64 /usr/lib64 -Dprivlib=/usr/lib/perl5/5.8.8 -Dsitelib=/usr/lib/perl5/site_perl/5.8.8 -Dvendorlib=/usr/lib/perl5/vendor_perl/5.8.8 -Darchlib=/usr/lib64/perl5/5.8.8/x86_64-linux-thread-multi -Dsitearch=/usr/lib64/perl5/site_perl/5.8.8/x86_64-linux-thread-multi -Dvendorarch=/usr/lib64/perl5/vendor_perl/5.8.8/x86_64-linux-thread-multi -Darchname=x86_64-linux-thread-multi -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=define use64bitall=define 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 -m64 -mtune=generic', 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 20080704 (Red Hat 4.1.2-48)', 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='gcc', ldflags ='' libpth=/usr/local/lib64 /lib64 /usr/lib64 libs=-lresolv -lnsl -lgdbm -ldb -ldl -lm -lcrypt -lutil -lpthread -lc perllibs=-lresolv -lnsl -ldl -lm -lcrypt -lutil -lpthread -lc libc=, so=so, useshrplib=true, libperl=libperl.so gnulibc_version='2.5' Dynamic Linking: dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E -Wl,-rpath,/usr/lib64/perl5/5.8.8/x86_64-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 -m64 -mtune=generic' Locally applied patches: @INC for perl v5.8.8: /usr/lib64/perl5/site_perl/5.8.8/x86_64-linux-thread-multi /usr/lib/perl5/site_perl/5.8.8 /usr/lib/perl5/site_perl /usr/lib64/perl5/vendor_perl/5.8.8/x86_64-linux-thread-multi /usr/lib/perl5/vendor_perl/5.8.8 /usr/lib/perl5/vendor_perl /usr/lib64/perl5/5.8.8/x86_64-linux-thread-multi /usr/lib/perl5/5.8.8 . Environment for perl v5.8.8: HOME=/root LANG=en_US.UTF-8 LANGUAGE (unset) LD_LIBRARY_PATH (unset) LOGDIR (unset) PATH=/usr/local/jdk/bin:/usr/kerberos/sbin:/usr/kerberos/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/opt/dell/srvadmin/bin:/opt/dell/srvadmin/sbin:/usr/local/bin:/usr/X11R6/bin:/root/bin PERL_BADLANG (unset) SHELL=/bin/bash ```

p5pRT commented 13 years ago

From @cpansprout

On Thu Feb 17 09:07:03 2011\, dmuey wrote:

Hello\,

I am seeing several systems behaving strangely (details below) in regards to abs_path. I am still tracing this out and wanted to post the details for reference and in case one of you gurus see what the cause could be right off hand\, thanks!

[ -- Working server -- ]
\# perl \-MCwd \-Mstrict \-wle 'my $etc = Cwd&#8203;::abs\_path$"/etc"$;if
(defined $etc) { print "Defined: $etc" } else { print "Undefined"; }' Defined: /etc

[ -- Affected server -- ]
\# perl \-MCwd \-Mstrict \-wle 'my $etc = Cwd&#8203;::abs\_path$"/etc"$;if
(defined $etc) { print "Defined: $etc" } else { print "Undefined"; }' Undefined

[ -- lower level -- ]

If I add debug output before and after line 156 in Cwd.xs like so:
printf$"DEBUG Before %d %s\\n"\, errno\, resolved$;
struct stat sb;
if $lstat\(resolved\, &sb$ \!= 0\) \{
    printf$"DEBUG After %d %s\\n"\, errno\, resolved$;
    if $errno == ENOENT && p == NULL$ \{
        errno = serrno;
        return $resolved$;
    \}
    return $NULL$;
\}
printf$"DEBUG I got past the return\(NULL$ above"\);
and rebuild it\, then we now see that errno was changed from ENOENT to EINVAL and thus the return(NULL) is triggered:
\# perl \-I\. \-I\./blib/arch \-MCwd \-Mstrict \-wle 'my $etc =
Cwd::abs_path("/etc");if (defined $etc) { print "Defined: $etc" } else { print "Undefined"; }' DEBUG Before 2 /etc DEBUG After 22 /etc Undefined

It is the same if we change lstat() to PerlLIO_lstat()

[ -- misc info -- ]

Both servers are • 64 bit • CentOS release 5.5 (Final) • Using Cwd 3.33 (but installing older version results in the same behavior) • have “d_lstat” set to “define”

Working server: • This is perl\, v5.8.8 built for x86_64-linux • from RPM: perl.x86_64 4:5.8.8-32.el5_5.2 (another affected server had perl.x86_64 4:5.8.8-27.el5 installed)

Affected server (the server this perlbug was sent from): • This is perl\, v5.8.8 built for x86_64-linux-thread-multi • from RPM: perl.x86_64 4:5.8.8-32.el5_5.1 (another affected server had perl.x86_64 4:5.8.8-27.el5 installed)

I cannot produce this on Mac OS X. Does the affected server remain right itself if you switch to a non-threaded build?

p5pRT commented 13 years ago

The RT System itself - Status changed from 'new' to 'open'

p5pRT commented 13 years ago

From dmuey@cpan.org

I cannot produce this on Mac OS X.

Right\, it is only reproducible on certain machines.

Does the affected server remain right itself if you switch to a non-threaded build?

As a matter of fact it does\, nice!

So it appears to be a (64bit) threading issue …

p5pRT commented 13 years ago

From webmaster@simplemood.com

I cannot produce this on Mac OS X.

Right\, it is only reproducible on certain machines.

Does the affected server remain right itself if you switch to a non-threaded build?

As a matter of fact it does\, nice!

So it appears to be a (64bit) threading issue …

p5pRT commented 11 years ago

From @jkeenan

On Thu Feb 24 00:43:58 2011\, webmaster@simplemood.com wrote:

I cannot produce this on Mac OS X.

Right\, it is only reproducible on certain machines.

Does the affected server remain right itself if you switch to a non-threaded build?

As a matter of fact it does\, nice!

So it appears to be a (64bit) threading issue …

Tonight I built a threaded perl on the Dromedary server\, at blead\, and then attempted to reproduce the problem the OP reported in early 2011.

##### sh ./Configure -des -Dusedevel -Dusethreads -Duseithreads make -j8 ##### ./perl -I./lib -MCwd -Mstrict -wle 'my $etc = Cwd::abs_path("/etc");if (defined $etc) { print "Defined: $etc" } else { print "Undefined"; }' ##### Defined: /etc #####

Granted\, I did not configure with the long list of arguments the OP did. But this tends not to support the presence of a problem.

Can anyone confirm? Is this ticket closable?

Thank you very much. Jim Keenan

p5pRT commented 10 years ago

From @jkeenan

On Fri Sep 06 20:09:25 2013\, jkeenan wrote:

On Thu Feb 24 00:43:58 2011\, webmaster@simplemood.com wrote:

I cannot produce this on Mac OS X.

Right\, it is only reproducible on certain machines.

Does the affected server remain right itself if you switch to a non-threaded build?

As a matter of fact it does\, nice!

So it appears to be a (64bit) threading issue …

Tonight I built a threaded perl on the Dromedary server\, at blead\, and then attempted to reproduce the problem the OP reported in early 2011.

##### sh ./Configure -des -Dusedevel -Dusethreads -Duseithreads make -j8 ##### ./perl -I./lib -MCwd -Mstrict -wle 'my $etc = Cwd::abs_path("/etc");if (defined $etc) { print "Defined: $etc" } else { print "Undefined"; }' ##### Defined: /etc #####

Granted\, I did not configure with the long list of arguments the OP did. But this tends not to support the presence of a problem.

Can anyone confirm? Is this ticket closable?

Thank you very much. Jim Keenan

We have not heard from the original poster in 2-3/4 years. No one has provided evidence that this is not fixed in blead.

So I am taking this ticket for the purpose of closing it within 7 days unless someone objects.

Thank you very much. Jim Keenan

p5pRT commented 10 years ago

From @jkeenan

On Sun Nov 24 09:50:35 2013\, jkeenan wrote:

We have not heard from the original poster in 2-3/4 years. No one has provided evidence that this is not fixed in blead.

So I am taking this ticket for the purpose of closing it within 7 days unless someone objects.

Closing as per schedule.

p5pRT commented 10 years ago

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

Perl / perl5