[BUG] zgetdir() in a directory of a bind mount returns "."

[BUG] zgetdir() in a directory of a bind mount returns "."

[Matthias Lederhofer]

Hi,

This happened when I ran sudo because sudo unsets $PWD.  Example how
to reproduce this (worked on multiple machines running linux):

# setup
mkdir -p /tmp/a/b/c /tmp/bind
mount -o bind /tmp/a/b /tmp/bind
cd /tmp/bind
# bug if output is "."
PWD=/tmp zsh -c pwd
# cleanup
cd /
umount /tmp/bind
rm -r /tmp/a /tmp/bind

The source and target directory of the bind mount have to be in
different directories.  With -DUSE_GETCWD=1 the bug does not occur.

Re: [BUG] zgetdir() in a directory of a bind mount returns "."

[Matthias Lederhofer]

The problem is that one device can be mounted on itself using bind
mounts.  In this case in line 311 of compat.c pdev and dev are equal
but the inodes differ because readdir() returns the inode of the
target directory of the bind mount and stat(".") in line 252 returned
the inode of the source directory.
Undefining HAVE_STRUCT_DIRENT_D_INO works and I don't know if there is
any other way to work with bind-mounts than not using the inode
returned by readdir().

Re: [BUG] zgetdir() in a directory of a bind mount returns "."

[Clint Adams]

On Sun, Nov 05, 2006 at 08:44:35AM +0100, Matthias Lederhofer wrote:
> The problem is that one device can be mounted on itself using bind
> mounts.  In this case in line 311 of compat.c pdev and dev are equal
> but the inodes differ because readdir() returns the inode of the
> target directory of the bind mount and stat(".") in line 252 returned
> the inode of the source directory.
> Undefining HAVE_STRUCT_DIRENT_D_INO works and I don't know if there is
> any other way to work with bind-mounts than not using the inode
> returned by readdir().

I think I recall something similar happening with chroots.