From: Karel Zak <kzak@redhat.com>
To: Edward Diener <eldlistmailingz@tropicsoft.com>
Cc: util-linux@vger.kernel.org
Subject: Re: Using libmount to track mount/umount
Date: Wed, 15 Aug 2018 09:03:45 +0200 [thread overview]
Message-ID: <20180815070345.qeazo2cqktwu6xyi@ws.net.home> (raw)
In-Reply-To: <62d391f1-3fd7-1acc-b57e-103a4bbd5244@tropicsoft.com>
On Tue, Aug 14, 2018 at 09:18:26AM -0400, Edward Diener wrote:
> I would like to use the libmount library to track end-user mount/umount
> commands. My first question regards the use of the monitor. What is the
> difference between userspace monitoring and kernel VFS monitoring ?
The userspace handler also monitor writes to /run/mount/utab, it's
important for options like user= or some NFS options maintained in
userspace only. Anyway, if do you not care about options than it's
probably enough to monitor VFS.
The userspace monitor has been mostly implemented for systemd where is
required to have information about all options, for more details see
https://github.com/systemd/systemd/blob/master/src/core/mount.c#L1701
See also test program in the code:
https://github.com/karelzak/util-linux/blob/master/libmount/src/monitor.c#L823
The another possibility to monitor VFS is to use directly poll() for
/proc/self/mountinfo and than mnt_new_tabdiff(), see findmnt --poll:
https://github.com/karelzak/util-linux/blob/master/misc-utils/findmnt.c#L1071
In this case you do not need the mnt_new_monitor(), but libmnt_monitor
is probably better for complex things and epoll().
Karel
--
Karel Zak <kzak@redhat.com>
http://karelzak.blogspot.com
prev parent reply other threads:[~2018-08-15 9:54 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-14 13:18 Using libmount to track mount/umount Edward Diener
2018-08-15 7:03 ` Karel Zak [this message]
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