Re: Segfault in "rm -rf" with really deep dir-tree

[Sten Eriksson]

Bob Proulx wrote:

> The version of rm you are using is 4.0.36 from the GNU fileutils
> package.  And that happens to be later than 4.0s (equivalent to 4.0.19
> in the new numbering) that the fix was reported fixed in.  It is
> possible that a glibc problem is occurring on your system.


I dont think it's a glibc or kernel problem, I have managed do both 
create and delete directory-trees deeper with other tools (perl 
one-liners and smallish c-hacks, see further down).

> I believe I am running into the filesystem max path length in both
> cases.  It just can't make a path any deeper at that point.


Really?! I think its more of a shell-limit when creating the directories 
(se further down). I have not actually tested how deep I can make the 
tree, since the point was just to proove that 'rm' dies rather than 
informing the user of its problems.


> But using rm version 4.1 I cannot create any failures removing that
> deep path on either system.


I don't think a tree with a depth of 4202 is any problem, I actually 
don't know how large it has to be to break rm, it may vary from system 
to system.

 - - - -

I fetched the 4.1 tarball and made another test:

 [1st we make a tree 19999 dirs deep]
# perl -e 'for($i=0;$i<20000;$i++){mkdir "z";system("/bin/sync");chdir 
z";print "$i ";}'

 [As usual the 4.0.36 version segfaults]
# rm -rf z
Segmentation fault (core dumped)

 [And so does the 4.1 version]
# ./fileutils-4.1/src/rm --version
rm (fileutils) 4.1
Written by Paul Rubin, David MacKenzie, Richard Stallman, and Jim Meyering.

Copyright (C) 2001 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
# ./fileutils-4.1/src/rm -rf z
Segmentation fault (core dumped)

 [Other tool, pike, happily deletes what perl created]
# pike -e 'int 
zc=0;while(file_stat("z",0)){cd("z");zc++;write("%d.",zc);};write("\n");for(;zc>0;zc--){cd("..");write("%d-",Stdio.recursive_rm("z"));write("%d.",zc);}'

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 / Sten Eriksson                | Mail: address@hidden
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