1 files changed, 55 insertions, 0 deletions
diff --git a/qga/commands-posix.c b/qga/commands-posix.c
index c83d26d0a5..c253f97fa7 100644
--- a/qga/commands-posix.c
+++ b/qga/commands-posix.c
@@ -135,6 +135,61 @@ int64_t qmp_guest_get_time(Error **errp)
    return time_ns;
 }
 
+void qmp_guest_set_time(int64_t time_ns, Error **errp)
+{
+    int ret;
+    int status;
+    pid_t pid;
+    Error *local_err = NULL;
+    struct timeval tv;
+
+    /* year-2038 will overflow in case time_t is 32bit */
+    if (time_ns / 1000000000 != (time_t)(time_ns / 1000000000)) {
+        error_setg(errp, "Time %" PRId64 " is too large", time_ns);
+        return;
+    }
+
+    tv.tv_sec = time_ns / 1000000000;
+    tv.tv_usec = (time_ns % 1000000000) / 1000;
+
+    ret = settimeofday(&tv, NULL);
+    if (ret < 0) {
+        error_setg_errno(errp, errno, "Failed to set time to guest");
+        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) {
+        error_setg_errno(errp, errno, "failed to create child process");
+        return;
+    }
+
+    ga_wait_child(pid, &status, &local_err);
+    if (error_is_set(&local_err)) {
+        error_propagate(errp, local_err);
+        return;
+    }
+
+    if (!WIFEXITED(status)) {
+        error_setg(errp, "child process has terminated abnormally");
+        return;
+    }
+
+    if (WEXITSTATUS(status)) {
+        error_setg(errp, "hwclock failed to set hardware clock to system time");
+        return;
+    }
+}
+
 typedef struct GuestFileHandle {
     uint64_t id;
     FILE *fh;