File::Find::find can fail to chdir out of a long length named directory

# New Ticket Created by  "Davies, Alex" 
# Please include the string:  [perl #44819]
# in the subject line of all future correspondence about
this issue. 
# <URL: h
ttp://rt.perl.org/rt3/Ticket/Display.html?id=44819 >


This is a bug report for perl from adaviesptc.com,
generated with the help of perlbug 1.35 running under perl
v5.8.7.


------------------------------------------------------------
-----
[Please enter your report here]


On Windows XP i've seen File::Find::find fail with:

  Can't cd to /dir/####../../..

where the #'s are a long filename (~256 characters)

[Also note the error message does not include a separating
'/'
between the dir_name and ../../..'s, or the value of $!,
which
happens to be 'No such file or directory'.]

It looks like chdir("../../../..") is hitting some
kind of
too long pathname issue.

Here's a testcase that shows the problem:

# %<
use File::Find;

chdir '/' or die $!;

my $root_dir = '/long_dir_test';

-d $root_dir || mkdir($root_dir) || die "can't mkdir
$root_dir: $!n";

# Make a maximally length named directory
# Problem seems to be filename length sensitive
foreach my $dir_name ('d', 'di', 'dir') {
	chdir($root_dir) or die "can't chdir to $root_dir:
$!n";
	while (mkdir $dir_name) {
		chdir $dir_name or last;
	}
}

chdir('/') || die "can't chdir to /: $!n";

File::Find::find(sub {}, $root_dir); # this should die
# >%


By changing the code in File::Find to do multiple
individual
chdir("..")'s, it does not seem to hit the
problem.
The following minimal patch shows what i mean:


        while ( defined ($SE = pop Stack) ) {
            ($Level, $p_dir, $dir_rel, $nlink) = $SE;
            if ($CdLvl > $Level && !$no_chdir) {
+             if ($^O eq 'MSWin32') {
+               my $depth = $CdLvl - $Level;
+               while ($depth--) {
+                   chdir("..") or die "Could
not cd back to $dir_name:
$!n";
+               }
+             } else {
                my $tmp;
                if ($Is_MacOS) {
                    $tmp = (':' x ($CdLvl-$Level)) . ':';
 -939,6
+945,7 
                }
                die "Can't cd to $dir_name" .
$tmp
                    unless chdir ($tmp);
+             }
                $CdLvl = $Level;
            }


I'm not sure how this affects performance - probably for the
worse :-(
It might be possible to use the value of C< length($cwd)
+
length($dir_name) >
to determine if multiple chdir("..")s were
needed.


Cheers, alex.


[Please do not change anything below this line]
------------------------------------------------------------
-----
---
Flags:
    category=library
    severity=low
---
Site configuration information for perl v5.8.7:

Configured by adavies at Thu Aug 11 14:02:10 2005.

Summary of my perl5 (revision 5 version 8 subversion 7)
configuration:
  Platform:
    osname=MSWin32, osvers=5.1,
archname=MSWin32-x86-multi-thread
    uname=''
    config_args='undef'
    hint=recommended, useposix=true, d_sigaction=undef
    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='cl', ccflags ='-nologo -Gf -W3 -MD -DNDEBUG -O1
-DWIN32
-D_CONSOLE -DNO_STRICT -DHAVE_DES_FCRYPT 
-DPERL_IMPLICIT_CONTEXT
-DPERL_IMPLICIT_SYS -DUSE_PERLIO -DPERL_MSVCRT_READFIX',
    optimize='-MD -DNDEBUG -O1',
    cppflags='-DWIN32'
    ccversion='12.00.8804', gccversion='', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8,
byteorder=1234
    d_longlong=undef, longlongsize=8, d_longdbl=define,
longdblsize=10
    ivtype='long', ivsize=4, nvtype='double', nvsize=8,
Off_t='__int64',
lseeksize=8
    alignbytes=8, prototype=define
  Linker and Libraries:
    ld='link', ldflags ='-nologo -nodefaultlib -release
-libpath:"c:perl3libCORE"  -machine86'
    libpth=lib
    libs=  oldnames.lib kernel32.lib user32.lib gdi32.lib
winspool.lib
comdlg32.lib advapi32.lib shell32.lib ole32.lib
oleaut32.lib
netapi32.lib uuid.lib ws2_32.lib mpr.lib winmm.lib 
version.lib
odbc32.lib odbccp32.lib msvcrt.lib
    perllibs=  oldnames.lib kernel32.lib user32.lib
gdi32.lib
winspool.lib  comdlg32.lib advapi32.lib shell32.lib
ole32.lib
oleaut32.lib  netapi32.lib uuid.lib ws2_32.lib mpr.lib
winmm.lib
version.lib odbc32.lib odbccp32.lib msvcrt.lib
    libc=msvcrt.lib, so=dll, useshrplib=yes,
libperl=perl58.lib
    gnulibc_version='undef'
  Dynamic Linking:
    dlsrc=dl_win32.xs, dlext=dll, d_dlsymun=undef,
ccdlflags=' '
    cccdlflags=' ', lddlflags='-dll -nologo -nodefaultlib
-release
-libpath:"c:perl3libCORE"  -machine86'

Locally applied patches:
    

---
INC
for perl v5.8.7:
    C:/perl3/lib
    C:/perl3/site/lib
    .

---
Environment for perl v5.8.7:
    HOME=C:alex
    LANG (unset)
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
 
PATH=C:WINNTsystem32;C:WINNT;C:WINNTSystem32Wbem;C:pe
rl3bin;D:a
lexbin;C:cygwinbin;C:Program FilesPerforce;C:Program
FilesMicrosoft Visual StudioVC98Bin;C:Program
FilesMicrosoft Visual
StudioCommonMSDev98Bin
    PERL_BADLANG (unset)
    SHELL (unset)

On 21/08/07, via RT Davies, Alex <perlbug-followupperl.org> wrote:
> On Windows XP i've seen File::Find::find fail with:
>
>   Can't cd to /dir/####../../..
>
> where the #'s are a long filename (~256 characters)
>
> [Also note the error message does not include a
separating '/'
> between the dir_name and ../../..'s, or the value of
$!, which
> happens to be 'No such file or directory'.]
>
> It looks like chdir("../../../..") is hitting
some kind of
> too long pathname issue.

It's probably better to fix it in chdir() instead of putting
a
work-around in File::Find. Can this bug be reproduced
without
File::Find?