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hostnamed: don't cache local hostname either 

Querying the current hostname is cheap, hence let's not cache it. That
way it is much less likely we'll return out-of-date data.
This commit is contained in:
Lennart Poettering 2020-04-28 17:34:38 +02:00
parent a055076988
commit aa994368c9
1 changed files with 44 additions and 21 deletions
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65
src/hostname/hostnamed.c
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@ -36,7 +36,6 @@
#define VALID_DEPLOYMENT_CHARS (DIGITS LETTERS "-.:")
enum {
PROP_HOSTNAME,
PROP_STATIC_HOSTNAME,
PROP_PRETTY_HOSTNAME,
PROP_ICON_NAME,
@ -77,10 +76,6 @@ static int context_read_data(Context *c) {
context_reset(c);
c->data[PROP_HOSTNAME] = gethostname_malloc();
if (!c->data[PROP_HOSTNAME])
return -ENOMEM;
r = read_etc_hostname(NULL, &c->data[PROP_STATIC_HOSTNAME]);
if (r < 0 && r != -ENOENT)
return r;
@ -244,12 +239,22 @@ static bool hostname_is_useful(const char *hn) {
return !isempty(hn) && !is_localhost(hn);
}
static int context_update_kernel_hostname(Context *c) {
const char *static_hn;
const char *hn;
static int context_update_kernel_hostname(
Context *c,
const char *transient_hn) {
const char *static_hn, *hn;
struct utsname u;
assert(c);
if (!transient_hn) {
/* If no transient hostname is passed in, then let's check what is currently set. */
assert_se(uname(&u) >= 0);
transient_hn =
isempty(u.nodename) || streq(u.nodename, "(none)") ? NULL : u.nodename;
}
static_hn = c->data[PROP_STATIC_HOSTNAME];
/* /etc/hostname with something other than "localhost"
@ -258,8 +263,8 @@ static int context_update_kernel_hostname(Context *c) {
hn = static_hn;
/* ... the transient hostname, (ie: DHCP) comes next ... */
else if (!isempty(c->data[PROP_HOSTNAME]))
hn = c->data[PROP_HOSTNAME];
else if (!isempty(transient_hn))
hn = transient_hn;
/* ... fallback to static "localhost.*" ignored above ... */
else if (!isempty(static_hn))
@ -342,6 +347,27 @@ static int context_write_data_machine_info(Context *c) {
return write_env_file_label("/etc/machine-info", l);
}
static int property_get_hostname(
sd_bus *bus,
const char *path,
const char *interface,
const char *property,
sd_bus_message *reply,
void *userdata,
sd_bus_error *error) {
_cleanup_free_ char *current = NULL;
int r;
r = gethostname_strict(&current);
if (r == -ENXIO)
return sd_bus_message_append(reply, "s", FALLBACK_HOSTNAME);
if (r < 0)
return r;
return sd_bus_message_append(reply, "s", current);
}
static int property_get_icon_name(
sd_bus *bus,
const char *path,
@ -405,8 +431,8 @@ static int property_get_uname_field(
static int method_set_hostname(sd_bus_message *m, void *userdata, sd_bus_error *error) {
Context *c = userdata;
const char *name;
int interactive;
int r;
int interactive, r;
struct utsname u;
assert(m);
assert(c);
@ -424,7 +450,8 @@ static int method_set_hostname(sd_bus_message *m, void *userdata, sd_bus_error *
if (!hostname_is_valid(name, false))
return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid hostname '%s'", name);
if (streq_ptr(name, c->data[PROP_HOSTNAME]))
assert_se(uname(&u) >= 0);
if (streq_ptr(name, u.nodename))
return sd_bus_reply_method_return(m, NULL);
r = bus_verify_polkit_async(
@ -441,17 +468,13 @@ static int method_set_hostname(sd_bus_message *m, void *userdata, sd_bus_error *
if (r == 0)
return 1; /* No authorization for now, but the async polkit stuff will call us again when it has it */
r = free_and_strdup(&c->data[PROP_HOSTNAME], name);
if (r < 0)
return r;
r = context_update_kernel_hostname(c);
r = context_update_kernel_hostname(c, name);
if (r < 0) {
log_error_errno(r, "Failed to set hostname: %m");
return sd_bus_error_set_errnof(error, r, "Failed to set hostname: %m");
}
log_info("Changed hostname to '%s'", strna(c->data[PROP_HOSTNAME]));
log_info("Changed hostname to '%s'", name);
(void) sd_bus_emit_properties_changed(sd_bus_message_get_bus(m), "/org/freedesktop/hostname1", "org.freedesktop.hostname1", "Hostname", NULL);
@ -497,7 +520,7 @@ static int method_set_static_hostname(sd_bus_message *m, void *userdata, sd_bus_
if (r < 0)
return r;
r = context_update_kernel_hostname(c);
r = context_update_kernel_hostname(c, NULL);
if (r < 0) {
log_error_errno(r, "Failed to set hostname: %m");
return sd_bus_error_set_errnof(error, r, "Failed to set hostname: %m");
@ -671,7 +694,7 @@ static int method_get_product_uuid(sd_bus_message *m, void *userdata, sd_bus_err
static const sd_bus_vtable hostname_vtable[] = {
SD_BUS_VTABLE_START(0),
SD_BUS_PROPERTY("Hostname", "s", NULL, offsetof(Context, data) + sizeof(char*) * PROP_HOSTNAME, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_PROPERTY("Hostname", "s", property_get_hostname, 0, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_PROPERTY("StaticHostname", "s", NULL, offsetof(Context, data) + sizeof(char*) * PROP_STATIC_HOSTNAME, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_PROPERTY("PrettyHostname", "s", NULL, offsetof(Context, data) + sizeof(char*) * PROP_PRETTY_HOSTNAME, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_PROPERTY("IconName", "s", property_get_icon_name, 0, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),