Re: [Bug-tar] Bug in remove-files

[Nathan Stratton Treadway]

On Tue, Sep 24, 2013 at 14:04:55 +0300, Sergey Poznyakoff wrote:
> Strand, Jörgen <address@hidden> ha escrit:
> 
> > When using -remove-files together with -r and -C wrong files will be 
> > removed.
> 
> Thanks for reporting. I've pushed commit e3d28d84, which fixes this bug,
> as well as other issues reported by Nathan.

I took a quick look at this patch, and noticed that there is still an
"actual" chdir call left, in names.c:name_next_elt() ... and so it's
possible to confuse the new tar_getcwd() function by using two -C
options (when in --create/non-incremental mode):

  $ mkdir foo
  $ echo foo/file > foo/file
  $ mkdir bar
  $ echo bar/file > bar/file


  $ find 
  .
  ./foo
  ./foo/file
  ./bar
  ./bar/file


  $ tar -cvf foo.tar --remove-files -C foo file -C ../bar file
  file
  file
  $ find
  .
  ./foo
  ./bar
  ./bar/file
  ./foo.tar

If I look at an strace, both unlink calls point to a path that includes the 
first
-C directory:
unlinkat(AT_FDCWD, "/home/nathanst/tartest/foo/file", 0) = 0
unlinkat(AT_FDCWD, "/home/nathanst/tartest/foo/file", 0) = -1 ENOENT (No such 
file or directory)



(Basically tar_getcwd() only looks up the "actual" cwd once, but in this
code path the "actual" cwd does change over the course of the program
run....)


                                                        Nathan

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