A question about extended attributes of filesystem objects (setfattr command)
I have a question regarding
Attributes of symlinks vs. the files pointed to
If I try to attach name:value pair to object symlink file then I'll get: "Operation not permitted"
reading the man pages of setfattr (or attr) I thought that it operates on the attributes of the symbolic link itself.
show:
-----
touch f
ln -s f l
setfattr -n user.filename -v ascii1 f l
setfattr -h -n user.filename -v ascii2 f getfattr -d f l
setfattr -h -n user.filename -v ascii3 l setfattr -h --no-dereference -n user.filename -v ascii4 l getfattr -d f l
so, my question is : what is expected ?
I've
libattr-devel-2.2.0-1
libattr-2.2.0-1
attr-2.2.0-1
and a 2.6.7 kernel
many thanks,
regards,
Signature · 3 lines
Jacky Malcles B1-403 Email : [email protected] Bull SA, 1 rue de Provence, B.P 208, 38432 Echirolles CEDEX, FRANCE Tel : 04.76.29.73.14
Gidday,
Quoted 5 lines
I have a question regarding
Attributes of symlinks vs. the files pointed toIf I try to attach name:value pair to object symlink file then I'll get: "Operation not permitted"
What file system are you using? If ext2, ext3 (or patched kernel supporting Reiserfs EAs), did you mount with "-o user_xattr? (The above error suggests you haven't used this option.)
Quoted 2 lines
reading the man pages of setfattr (or attr) I thought that it operates on the attributes of the symbolic link itself.
No, these commands follow symbolic links.
Quoted 11 lines
show:
-----
touch f
ln -s f l
setfattr -n user.filename -v ascii1 f l
setfattr -h -n user.filename -v ascii2 f getfattr -d f l
setfattr -h -n user.filename -v ascii3 l setfattr -h --no-dereference -n user.filename -v ascii4 l getfattr -d f l
Quoted 1 line
so, my question is : what is expected ?
attr(5) specifically notes that USER EAs are disallowed on symbolic links, but this is rather an issu that affects the use of lsetxattr(2).
Cheers,
Michael
Signature · 2 lines
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Quoted 6 lines · Michael Kerrisk
Gidday,
Quoted 3 lines
I have a question regarding
Attributes of symlinks vs. the files pointed to
Quoted 6 lines
Quoted 2 lines
If I try to attach name:value pair to object symlink file then I'll get: "Operation not permitted"
What file system are you using? If ext2, ext3 (or patched kernel supporting Reiserfs EAs), did you mount with "-o
user_xattr? (The above error suggests you haven't used this option.)
# mount /dev/sdb3 on /a type ext3 (rw,acl,user_xattr) ...etc...
Quoted 18 lines
Quoted 3 lines
reading the man pages of setfattr (or attr) I thought that it operates on the attributes of the symbolic link itself.
No, these commands follow symbolic links.
Quoted 12 lines
show:
-----
touch f
ln -s f l
setfattr -n user.filename -v ascii1 f l
setfattr -h -n user.filename -v ascii2 f getfattr -d f l
setfattr -h -n user.filename -v ascii3 l setfattr -h --no-dereference -n user.filename -v ascii4 l getfattr -d f lso, my question is : what is expected ?
should have added this:
[root@t20 acl]# show
# file: f
user.filename="ascii2"
# file: l
user.filename="ascii2"
setfattr: l: Operation not permitted
setfattr: l: Operation not permitted
# file: f
user.filename="ascii2"
# file: l
user.filename="ascii2"
[root@t20 acl]#
Quoted 18 lines
attr(5) specifically notes that USER EAs are disallowed on symbolic links, but this is rather an issu that affects the use of lsetxattr(2).
Cheers,
Michael
--
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Signature · 3 lines
Jacky Malcles B1-403 Email : [email protected] Bull SA, 1 rue de Provence, B.P 208, 38432 Echirolles CEDEX, FRANCE Tel : 04.76.29.73.14
Salut Jacky,
Quoted 6 lines
Quoted 6 lines
Quoted 5 lines
I have a question regarding
Attributes of symlinks vs. the files pointed toIf I try to attach name:value pair to object symlink file then I'll get: "Operation not permitted"
Quoted 7 lines
Quoted 3 lines
What file system are you using? If ext2, ext3 (or patched kernel supporting Reiserfs EAs), did you mount with "-o
user_xattr? (The above error suggests you haven't used this option.)# mount /dev/sdb3 on /a type ext3 (rw,acl,user_xattr) ...etc...
Okay.
Quoted 5 lines
Quoted 5 lines
Quoted 2 lines
reading the man pages of setfattr (or attr) I thought that it operates on the attributes of the symbolic link itself.
No, these commands follow symbolic links.
Quoted 9 lines
Quoted 9 lines
Quoted 9 lines
show:
-----
touch f
ln -s f l
setfattr -n user.filename -v ascii1 f l
setfattr -h -n user.filename -v ascii2 f getfattr -d f l
setfattr -h -n user.filename -v ascii3 l setfattr -h --no-dereference -n user.filename -v ascii4 l
I'm sorry -- I missed the above "--no-dereference"; that's why my point below becomes relevant.
Quoted 17 lines
Quoted 3 lines
Quoted 3 lines
getfattr -d f l
so, my question is : what is expected ?
should have added this:
[root@t20 acl]# show
# file: f
user.filename="ascii2"# file: l
user.filename="ascii2"setfattr: l: Operation not permitted
setfattr: l: Operation not permitted
# file: f
user.filename="ascii2"
Quoted 4 lines
# file: l
user.filename="ascii2"[root@t20 acl]#
But note the following:
Quoted 3 lines
Quoted 3 lines
attr(5) specifically notes that USER EAs are disallowed on symbolic links, but this is rather an issu that affects the use of lsetxattr(2).
or setfattr if you specify "--no-dereference"...
There is a reason for this restriction: for a symbolic link, all permissions are enabled for all users, and these permissions cannot be changed. This means that permissions cannot be used (as they would be with regular files) to prevent arbitrary users from placing user EAs on a symbolic link. Thus all users are prevented from creating user EAs on the symbolic link.
Michael
Signature · 2 lines
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Quoted 9 lines · Michael Kerrisk
Gidday,
Quoted 5 lines
I have a question regarding
Attributes of symlinks vs. the files pointed toIf I try to attach name:value pair to object symlink file then I'll get: "Operation not permitted"
Quoted 22 lines
What file system are you using? If ext2, ext3 (or patched kernel supporting Reiserfs EAs), did you mount with "-o
user_xattr? (The above error suggests you haven't used this option.)Quoted 2 lines
reading the man pages of setfattr (or attr) I thought that it operates on the attributes of the symbolic link itself.
No, these commands follow symbolic links.
Quoted 12 lines
show:
-----
touch f
ln -s f l
setfattr -n user.filename -v ascii1 f l
setfattr -h -n user.filename -v ascii2 f getfattr -d f l
setfattr -h -n user.filename -v ascii3 l setfattr -h --no-dereference -n user.filename -v ascii4 l getfattr -d f lso, my question is : what is expected ?
thanks Michael,
below is what I was trying to find out !!
Quoted 17 lines
attr(5) specifically notes that USER EAs are disallowed on symbolic links, but this is rather an issu that affects the use of lsetxattr(2).
Cheers,
Michael
--
"Sie haben neue Mails!" - Die GMX Toolbar informiert Sie beim Surfen! Jetzt aktivieren unter http://www.gmx.net/info-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Signature · 3 lines
Jacky Malcles B1-403 Email : [email protected] Bull SA, 1 rue de Provence, B.P 208, 38432 Echirolles CEDEX, FRANCE Tel : 04.76.29.73.14