static int context_update_kernel_hostname(Context *c) {
const char *static_hn;
const char *hn;
assert(c);
static_hn = c->data[PROP_STATIC_HOSTNAME];
/* /etc/hostname with something other than "localhost"
* has the highest preference ... */
if (hostname_is_useful(static_hn))
hn = static_hn;
/* ... the transient host name, (ie: DHCP) comes next ... */
else if (!isempty(c->data[PROP_HOSTNAME]))
hn = c->data[PROP_HOSTNAME];
/* ... fallback to static "localhost.*" ignored above ... */
else if (!isempty(static_hn))
hn = static_hn;
/* ... and the ultimate fallback */
else
hn = "localhost";
if (sethostname_idempotent(hn) < 0)
return -errno;
return 0;
}
int hostname_setup(void) {
int r;
_cleanup_free_ char *b = NULL;
const char *hn;
bool enoent = false;
r = read_hostname_config("/etc/hostname", &b);
if (r < 0) {
if (r == -ENOENT)
enoent = true;
else
log_warning_errno(r, "Failed to read configured hostname: %m");
hn = NULL;
} else
hn = b;
if (isempty(hn)) {
/* Don't override the hostname if it is already set
* and not explicitly configured */
if (hostname_is_set())
return 0;
if (enoent)
log_info("No hostname configured.");
hn = "localhost";
}
r = sethostname_idempotent(hn);
if (r < 0)
return log_warning_errno(r, "Failed to set hostname to <%s>: %m", hn);
log_info("Set hostname to <%s>.", hn);
return 0;
}