diff options
Diffstat (limited to 'doc/dbus-specification.xml')
-rw-r--r-- | doc/dbus-specification.xml | 22 |
1 files changed, 14 insertions, 8 deletions
diff --git a/doc/dbus-specification.xml b/doc/dbus-specification.xml index 977734d7..1e4ac4f5 100644 --- a/doc/dbus-specification.xml +++ b/doc/dbus-specification.xml @@ -2311,11 +2311,24 @@ UUID representing the identity of the machine the process is running on. This UUID must be the same for all processes on a single system at least until that system next reboots. It should be the same across reboots - if possible, but may change due to reconfiguration or hardware changes. + if possible, but this is not always possible to implement and is not + guaranteed. It does not matter which object path a GetMachineId is sent to. The reference implementation handles this method automatically. </para> <para> + The UUID is intended to be per-instance-of-the-operating-system, so may represent + a virtual machine running on a hypervisor, rather than a physical machine. + Basically if two processes see the same UUID, they should also see the same + shared memory, UNIX domain sockets, process IDs, and other features that require + a running OS kernel in common between the processes. + </para> + <para> + The UUID is often used where other programs might use a hostname. Hostnames + can change without rebooting, however, or just be "localhost" - so the UUID + is more robust. + </para> + <para> The UUID must contain 128 bits of data and be hex-encoded (meaning, the hex string contains 32 ASCII characters). The hex-encoded string may not contain hyphens or other non-hex-digit characters, and it must be exactly 32 characters long. @@ -2323,13 +2336,6 @@ since the UNIX epoch in the last 32 bits of the UUID, and to put randomly-generated bits in the first 96 bits of the UUID. </para> - <para> - The UUID is intended to be per-instance-of-the-operating-system, so may represent - a virtual machine running on a hypervisor, rather than a physical machine. - Basically if two processes see the same UUID, they should also see the same - shared memory, UNIX domain sockets, process IDs, and other features that require - a running OS kernel in common between the processes. - </para> </sect2> <sect2 id="standard-interfaces-introspectable"> |