uuidd - UUID generation daemon
The uuidd daemon is used by the UUID library to generate
universally unique identifiers (UUIDs), especially time-based UUIDs, in a
secure and guaranteed-unique fashion, even in the face of large numbers of
threads running on different CPUs trying to grab UUIDs.
-C, --cont-clock opt_arg
Activate continuous clock handling for time based UUIDs.
uuidd could use all possible clock values, beginning with the
daemon’s start time. The optional argument can be used to set a value
for the max_clock_offset. This gurantees, that a clock value of a UUID will
always be within the range of the max_clock_offset. '-C' or '--cont-clock'
enables the feature with a default max_clock_offset of 2 hours.
'-C<NUM>[hd]' or '--cont-clock=<NUM>[hd]' enables the feature with
a max_clock_offset of NUM seconds. In case of an appended h or d, the NUM
value is read in hours or days. The minimum value is 60 seconds, the maximum
value is 365 days.
-d, --debug
Run uuidd in debugging mode. This prevents
uuidd from running as a daemon.
-F, --no-fork
Do not daemonize using a double-fork.
-k, --kill
If currently a uuidd daemon is running, kill it.
-n, --uuids number
When issuing a test request to a running uuidd,
request a bulk response of number UUIDs.
-P, --no-pid
Do not create a pid file.
-p, --pid path
Specify the pathname where the pid file should be
written. By default, the pid file is written to
{runstatedir}/uuidd/uuidd.pid.
-q, --quiet
Suppress some failure messages.
-r, --random
Test uuidd by trying to connect to a running uuidd daemon
and request it to return a random-based UUID.
-S, --socket-activation
Do not create a socket but instead expect it to be
provided by the calling process. This implies
--no-fork and
--no-pid. This option is intended to be used only with
systemd(1). It needs to be enabled with a configure option.
-s, --socket path
Make uuidd use this pathname for the unix-domain socket.
By default, the pathname used is {runstatedir}/uuidd/request. This
option is primarily for debugging purposes, since the pathname is hard-coded
in the libuuid library.
-T, --timeout number
Make uuidd exit after number seconds of
inactivity.
-t, --time
Test uuidd by trying to connect to a running uuidd
daemon and request it to return a time-based UUID.
-h, --help
Display help text and exit.
-V, --version
Print version and exit.
Start up a daemon, print 42 random keys, and then stop the
daemon:
uuidd -p /tmp/uuidd.pid -s /tmp/uuidd.socket
uuidd -d -r -n 42 -s /tmp/uuidd.socket
uuidd -d -k -s /tmp/uuidd.socket
The uuidd daemon was written by Theodore Ts’o
<tytso@mit.edu>.
For bug reports, use the issue tracker at
<https://github.com/util-linux/util-linux/issues>.
The uuidd command is part of the util-linux package which
can be downloaded from Linux Kernel Archive
<https://www.kernel.org/pub/linux/utils/util-linux/>.