[Qemu-devel] [PATCH 3/3] qga: add guest-set-time command

[Lei Li <lilei@linux.vnet.ibm.com>]

Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com>
---
 qga/commands-posix.c |   57 ++++++++++++++++++++++++++++++++++++++++++++++++++
 qga/qapi-schema.json |   32 ++++++++++++++++++++++++++++
 2 files changed, 89 insertions(+), 0 deletions(-)

diff --git a/qga/commands-posix.c b/qga/commands-posix.c
index 190199d..7fff49a 100644
--- a/qga/commands-posix.c
+++ b/qga/commands-posix.c
@@ -121,6 +121,63 @@ struct HostTimeInfo *qmp_guest_get_time(Error **errp)
     return host_time;
 }
 
+void qmp_guest_set_time(bool has_seconds, int64_t seconds,
+                        bool has_microseconds, int64_t microseconds,
+                        bool has_utc_offset, int64_t utc_offset, Error **errp)
+{
+    int ret;
+    int status;
+    pid_t pid, rpid;
+    struct timeval tv;
+    HostTimeInfo *host_time;
+
+    if ((!has_seconds) && (!has_microseconds) && (!has_utc_offset)) {
+        host_time = get_host_time();
+        if (!host_time) {
+            error_set(errp, QERR_QGA_COMMAND_FAILED, "Failed to set guest time");
+            return;
+        }
+        tv.tv_sec = host_time->seconds;
+        tv.tv_usec = host_time->microseconds;
+    } else if (has_seconds && has_microseconds && has_utc_offset) {
+        tv.tv_sec = (time_t) seconds + utc_offset;
+        tv.tv_usec = (time_t) microseconds;
+    } else {
+        error_set(errp, QERR_INVALID_PARAMETER, "parameter missing");
+        return;
+    }
+
+    ret = settimeofday(&tv, NULL);
+    if (ret < 0) {
+        error_set(errp, QERR_QGA_COMMAND_FAILED, strerror(errno));
+        return;
+    }
+
+    /* Set the Hardware Clock to the current System Time. */
+    pid = fork();
+    if (pid == 0) {
+        setsid();
+        reopen_fd_to_null(0);
+        reopen_fd_to_null(1);
+        reopen_fd_to_null(2);
+
+        execle("/sbin/hwclock", "hwclock", "-w", NULL, environ);
+        _exit(EXIT_FAILURE);
+    } else if (pid < 0) {
+        goto exit_err;
+    }
+
+    do {
+        rpid = waitpid(pid, &status, 0);
+    } while (rpid == -1 && errno == EINTR);
+    if (rpid == pid && WIFEXITED(status) && !WEXITSTATUS(status)) {
+        return;
+    }
+
+exit_err:
+    error_set(errp, QERR_UNDEFINED_ERROR);
+}
+
 typedef struct GuestFileHandle {
     uint64_t id;
     FILE *fh;
diff --git a/qga/qapi-schema.json b/qga/qapi-schema.json
index 4a8b93c..4649b55 100644
--- a/qga/qapi-schema.json
+++ b/qga/qapi-schema.json
@@ -117,6 +117,38 @@
   'returns': 'HostTimeInfo' }
 
 ##
+# @guest-set-time:
+#
+# Set guest time. If none arguments were given, will set
+# host time to guest.
+#
+# Right now, when a guest is paused or migrated to a file
+# then loaded from that file, the guest OS has no idea that
+# there was a big gap in the time. Depending on how long
+# the gap was, NTP might not be able to resynchronize the
+# guest.
+#
+# This command tries to set guest time based on the information
+# from host or an absolute value given by management app, and
+# set the Hardware Clock to the current System Time. This
+# will make it easier for a guest to resynchronize without
+# waiting for NTP.
+#
+# @seconds: #optional "seconds" time.
+#
+# @microseconds: #optional "microseconds" time.
+#
+# @utc-offset: #optional utc offset.
+#
+# Returns: Nothing on success.
+#
+# Since: 1.4
+##
+{ 'command': 'guest-set-time',
+  'data': { '*seconds': 'int', '*microseconds': 'int',
+            '*utc-offset': 'int' } }
+
+##
 # @GuestAgentCommandInfo:
 #
 # Information about guest agent commands.
-- 
1.7.7.6