6:18 a.m.
Hi all,
Currently, umask takes effect when we create device file via mknod, as
bellow commands show:
<fs> mknod-b 0760 8 1 /dev/sdf
<fs> ll /dev/sdf
brwxr----- 1 root root 8, 1 Apr 15 11:10 /sysroot/dev/sdf
But I wonder whether it is reasonable? For mknod(1), when we use option
-m mode, we set file permission bits to MODE, not a=rw - umask. Should
this also be applicable to mknod in guestfish, thus when we create
device file with mode set, umask doesn't take effect?
3:37 a.m.
New subject: Should umask takes effect when we create device file via mknod?
On Thu, Apr 15, 2010 at 07:18:15PM +0800, Yufang Zhang wrote:
Hi all,
Currently, umask takes effect when we create device file via mknod, as
bellow commands show:
><fs> mknod-b 0760 8 1 /dev/sdf
><fs> ll /dev/sdf
brwxr----- 1 root root 8, 1 Apr 15 11:10 /sysroot/dev/sdf
But I wonder whether it is reasonable? For mknod(1), when we use option
-m mode, we set file permission bits to MODE, not a=rw - umask. Should
this also be applicable to mknod in guestfish, thus when we create
device file with mode set, umask doesn't take effect?
I think it's reasonable for us to use the umask, but probably
it should be better documented.
In the daemon we use the mknod(2) system call which is documented
to be affected by umask:
The permissions are modified by the process’s umask in the usual way:
the permissions of the created node are (mode & ~umask).
But the behaviour is a little bit different from the mknod(1)
program.
We could add a mknod-mode command (see also mkdir-mode). If you
think this is worth it, then please file a bug or send a patch.
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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12:37 a.m.
On 04/17/2010 04:37 PM, Richard W.M. Jones wrote:
a mknod-mode command
File a bug as a feature request to track
this issue:
https://bugzilla.redhat.com/show_bug.cgi?id=583554
3:38 a.m.
New subject: Should umask takes effect when we create device file via mknod?
See also:
http://git.annexia.org/?p=libguestfs.git;a=blob;f=daemon/mknod.c;h=50865a...
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
virt-p2v converts physical machines to virtual machines. Boot with a
live CD or over the network (PXE) and turn machines into Xen guests.
http://et.redhat.com/~rjones/virt-p2v
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3 comments
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participants (2)
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Richard W.M. Jones -
Yufang Zhang