On 8/30/13 7:19 AM, Vasily Isaenko wrote:
> Dear XFS Members,
>
> In the XFS test suite there is a test case generic/314 "Test SGID inheritance on subdirectories".
> It is not specific to a particular filesystem thus selected for both xfs or ext4 test runs.
> In other words, the same behaviour is expected and enforced for XFS and EXT4.
Yep, and it passes on both of them, as well as on ext3, ext2, btrfs, and gfs2...
> However, I have been told that EXT4 and XFS may have different behaviour as the
> setgid-directory behavior is not guaranteed to work the same way on all filesystems.
"I have been told" ... I'm guessing that you have tested a filesystem which doesn't
behave this way? Which one?
> Shall XFS test case reflect that difference or enforcing the same behaviour is appropriate?
If you have information that a filesystem exists which does not inherit SGID, and
that this behavior is intentional and correct and standards-compliant, then feel
free to submit a patch.
However, I think you'll need to have a convincing argument against the man pages.
chmod(2) says:
S_ISGID (02000) set-group-ID (set process effective group ID on
execve(2); mandatory locking, as described in fcntl(2);
take a new file’s group from parent directory, as
described in chown(2) and mkdir(2))
mkdir(2) says:
The newly created directory will be owned by the effective user ID of the
process. If the directory containing the file has the set-group-ID bit
set, or if the file system is mounted with BSD group semantics (mount -o
bsdgroups or, synonymously mount -o grpid), the new directory will inherit
the group ownership from its parent; otherwise it will be owned by the
effective group ID of the process.
and chown(2) says:
NOTES
When a new file is created (by, for example, open(2) or mkdir(2)), its
owner is made the same as the file system user ID of the creating process.
The group of the file depends on a range of factors, including the type of
file system, the options used to mount the file system, and whether or not
the set-group-ID permission bit is enabled on the parent directory. If the
file system supports the -o grpid (or, synonymously -o bsdgroups) and
-o nogrpid (or, synonymously -o sysvgroups) mount(8) options, then the
rules are as follows:
* If the file system is mounted with -o grpid, then the group of a new file
is made the same as that of the parent directory.
* If the file system is mounted with -o nogrpid and the set-group-ID bit is
disabled on the parent directory, then the group of a new file is made
the same as the process’s file system GID.
* If the file system is mounted with -o nogrpid and the set-group-ID bit is
enabled on the parent directory, then the group of a new file is made the
same as that of the parent directory.
Thanks,
Eric
> Best regards,
> Vasily
>
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