hostnamed: don't cache uname() data

Let's not cache the uname(), it's very cheap to get it, and just means
we might get out of sync with what is current. After all, the data might
change IRL, due to setarch and stuff.

diff --git a/src/hostname/hostnamed.c b/src/hostname/hostnamed.c
index 701041c12adbcf16be7e47832d6e6c9c974b35f7..e20e9f6dadc6c3ed8d6e521d4e613a0a58b39381 100644 (file)
--- a/src/hostname/hostnamed.c
+++ b/src/hostname/hostnamed.c
@@ -43,9 +43,6 @@ enum {
         PROP_CHASSIS,
         PROP_DEPLOYMENT,
         PROP_LOCATION,
-        PROP_KERNEL_NAME,
-        PROP_KERNEL_RELEASE,
-        PROP_KERNEL_VERSION,
         PROP_OS_PRETTY_NAME,
         PROP_OS_CPE_NAME,
         PROP_HOME_URL,
@@ -77,20 +74,11 @@ static void context_clear(Context *c) {
 
 static int context_read_data(Context *c) {
         int r;
-        struct utsname u;
 
         assert(c);
 
         context_reset(c);
 
-        assert_se(uname(&u) >= 0);
-        c->data[PROP_KERNEL_NAME] = strdup(u.sysname);
-        c->data[PROP_KERNEL_RELEASE] = strdup(u.release);
-        c->data[PROP_KERNEL_VERSION] = strdup(u.version);
-        if (!c->data[PROP_KERNEL_NAME] || !c->data[PROP_KERNEL_RELEASE] ||
-            !c->data[PROP_KERNEL_VERSION])
-                return -ENOMEM;
-
         c->data[PROP_HOSTNAME] = gethostname_malloc();
         if (!c->data[PROP_HOSTNAME])
                 return -ENOMEM;
@@ -411,6 +399,22 @@ static int property_get_chassis(
         return sd_bus_message_append(reply, "s", name);
 }
 
+static int property_get_uname_field(
+                sd_bus *bus,
+                const char *path,
+                const char *interface,
+                const char *property,
+                sd_bus_message *reply,
+                void *userdata,
+                sd_bus_error *error) {
+
+        struct utsname u;
+
+        assert_se(uname(&u) >= 0);
+
+        return sd_bus_message_append(reply, "s", (char*) &u + PTR_TO_SIZE(userdata));
+}
+
 static int method_set_hostname(sd_bus_message *m, void *userdata, sd_bus_error *error) {
         Context *c = userdata;
         const char *name;
@@ -673,9 +677,9 @@ static const sd_bus_vtable hostname_vtable[] = {
         SD_BUS_PROPERTY("Chassis", "s", property_get_chassis, 0, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
         SD_BUS_PROPERTY("Deployment", "s", NULL, offsetof(Context, data) + sizeof(char*) * PROP_DEPLOYMENT, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
         SD_BUS_PROPERTY("Location", "s", NULL, offsetof(Context, data) + sizeof(char*) * PROP_LOCATION, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
-        SD_BUS_PROPERTY("KernelName", "s", NULL, offsetof(Context, data) + sizeof(char*) * PROP_KERNEL_NAME, SD_BUS_VTABLE_PROPERTY_CONST),
-        SD_BUS_PROPERTY("KernelRelease", "s", NULL, offsetof(Context, data) + sizeof(char*) * PROP_KERNEL_RELEASE, SD_BUS_VTABLE_PROPERTY_CONST),
-        SD_BUS_PROPERTY("KernelVersion", "s", NULL, offsetof(Context, data) + sizeof(char*) * PROP_KERNEL_VERSION, SD_BUS_VTABLE_PROPERTY_CONST),
+        SD_BUS_PROPERTY("KernelName", "s", property_get_uname_field, offsetof(struct utsname, sysname), SD_BUS_VTABLE_ABSOLUTE_OFFSET|SD_BUS_VTABLE_PROPERTY_CONST),
+        SD_BUS_PROPERTY("KernelRelease", "s", property_get_uname_field, offsetof(struct utsname, release), SD_BUS_VTABLE_ABSOLUTE_OFFSET|SD_BUS_VTABLE_PROPERTY_CONST),
+        SD_BUS_PROPERTY("KernelVersion", "s", property_get_uname_field, offsetof(struct utsname, version), SD_BUS_VTABLE_ABSOLUTE_OFFSET|SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("OperatingSystemPrettyName", "s", NULL, offsetof(Context, data) + sizeof(char*) * PROP_OS_PRETTY_NAME, SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("OperatingSystemCPEName", "s", NULL, offsetof(Context, data) + sizeof(char*) * PROP_OS_CPE_NAME, SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("HomeURL", "s", NULL, offsetof(Context, data) + sizeof(char*) * PROP_HOME_URL, SD_BUS_VTABLE_PROPERTY_CONST),