sd_id128_get_machine, sd_id128_get_boot, sd_id128_get_invocation — Retrieve 128-bit IDs
sd_id128_get_machine() returns the
machine ID of the executing host. This reads and parses the
file. This function caches the machine ID internally to make
retrieving the machine ID a cheap operation.
sd_id128_get_boot() returns the boot ID
of the executing kernel. This reads and parses the
/proc/sys/kernel/random/boot_id file exposed
by the kernel. It is randomly generated early at boot and is
unique for every running kernel instance. See
for more information. This function also internally caches the
returned ID to make this call a cheap operation.
sd_id128_get_invocation() returns the invocation ID of the currently executed
service. In its current implementation, this reads and parses the
variable that the service manager sets when activating a service, see
systemd.exec(5) for details. The
ID is cached internally. In future a different mechanism to determine the invocation ID may be added.
return UUID v4 compatible IDs.
sd_id128_get_machine() will also return a UUID v4-compatible
ID on new installations but might not on older. It is possible to convert the machine ID into a UUID v4-compatible
one. For more information, see
For more information about the "
The two calls return 0 on success (in which case
ret is filled in), or a negative
errno-style error code.
sd_id128_get_invocation() interfaces are available as a shared library, which can be compiled
and linked to with the "
libsystemd" pkg-config(1) file.