[Qemu-devel] [PULL 8/8] qga: Add `guest-get-timezone` command

[Michael Roth <mdroth@linux.vnet.ibm.com>]

From: Vinzenz Feenstra <vfeenstr@redhat.com>

Adds a new command `guest-get-timezone` reporting the currently
configured timezone on the system. The information on what timezone is
currently is configured is useful in case of Windows VMs where the
offset of the hardware clock is required to have the same offset. This
can be used for management systems like `oVirt` to detect the timezone
difference and warn administrators of the misconfiguration.

Signed-off-by: Vinzenz Feenstra <vfeenstr@redhat.com>
Reviewed-by: Sameeh Jubran <sameeh@daynix.com>
Tested-by: Sameeh Jubran <sameeh@daynix.com>
* moved stub implementation to end of function for consistency
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 qga/commands.c       | 38 ++++++++++++++++++++++++++++++++++++++
 qga/qapi-schema.json | 24 ++++++++++++++++++++++++
 2 files changed, 62 insertions(+)

diff --git a/qga/commands.c b/qga/commands.c
index 57a31bb..3333ed5 100644
--- a/qga/commands.c
+++ b/qga/commands.c
@@ -510,3 +510,41 @@ GuestHostName *qmp_guest_get_host_name(Error **err)
     }
     return result;
 }
+
+GuestTimezone *qmp_guest_get_timezone(Error **errp)
+{
+#if GLIB_CHECK_VERSION(2, 28, 0)
+    GuestTimezone *info = NULL;
+    GTimeZone *tz = NULL;
+    gint64 now = 0;
+    gint32 intv = 0;
+    gchar const *name = NULL;
+
+    info = g_new0(GuestTimezone, 1);
+    tz = g_time_zone_new_local();
+    if (tz == NULL) {
+        error_setg(errp, QERR_QGA_COMMAND_FAILED,
+                   "Couldn't retrieve local timezone");
+        goto error;
+    }
+
+    now = g_get_real_time() / G_USEC_PER_SEC;
+    intv = g_time_zone_find_interval(tz, G_TIME_TYPE_UNIVERSAL, now);
+    info->offset = g_time_zone_get_offset(tz, intv);
+    name = g_time_zone_get_abbreviation(tz, intv);
+    if (name != NULL) {
+        info->has_zone = true;
+        info->zone = g_strdup(name);
+    }
+    g_time_zone_unref(tz);
+
+    return info;
+
+error:
+    g_free(info);
+    return NULL;
+#else
+    error_setg(errp, QERR_UNSUPPORTED);
+    return NULL;
+#endif
+}
diff --git a/qga/qapi-schema.json b/qga/qapi-schema.json
index f25467a..5c325b1 100644
--- a/qga/qapi-schema.json
+++ b/qga/qapi-schema.json
@@ -1101,3 +1101,27 @@
 ##
 { 'command': 'guest-get-users',
   'returns': ['GuestUser'] }
+
+##
+# @GuestTimezone:
+#
+# @zone:    Timezone name
+# @offset:  Offset to UTC in seconds, negative numbers for time zones west of
+#           GMT, positive numbers for east
+#
+# Since: 2.10
+##
+{ 'struct': 'GuestTimezone',
+  'data':   { '*zone': 'str', 'offset': 'int' } }
+
+##
+# @guest-get-timezone:
+#
+# Retrieves the timezone information from the guest.
+#
+# Returns: A GuestTimezone dictionary.
+#
+# Since: 2.10
+##
+{ 'command': 'guest-get-timezone',
+  'returns': 'GuestTimezone' }
-- 
2.7.4