qemu-print: New qemu_printf(), qemu_vprintf() etc.

We commonly want to print to the current monitor if we have one, else
to stdout/stderr.  For stderr, have error_printf().  For stdout, all
we have is monitor_vfprintf(), which is rather unwieldy.  We often
print to stderr just because error_printf() is easier.

New qemu_printf() and qemu_vprintf() do exactly what's needed.  The
next commits will put them to use.

Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20190417190641.26814-12-armbru@redhat.com>

2 files changed, 43 insertions, 0 deletions

diff --git a/util/Makefile.objs b/util/Makefile.objs
index 835fcd69e2..9206878dec 100644
--- a/util/Makefile.objs
+++ b/util/Makefile.objs
@@ -23,6 +23,7 @@ util-obj-y += bitmap.o bitops.o hbitmap.o
 util-obj-y += fifo8.o
 util-obj-y += cacheinfo.o
 util-obj-y += error.o qemu-error.o
+util-obj-y += qemu-print.o
 util-obj-y += id.o
 util-obj-y += iov.o qemu-config.o qemu-sockets.o uri.o notify.o
 util-obj-y += qemu-option.o qemu-progress.o
diff --git a/util/qemu-print.c b/util/qemu-print.c
new file mode 100644
index 0000000000..86f9417af8
--- /dev/null
+++ b/util/qemu-print.c
@@ -0,0 +1,42 @@
+/*
+ * Print to stream or current monitor
+ *
+ * Copyright (C) 2019 Red Hat Inc.
+ *
+ * Authors:
+ *  Markus Armbruster <armbru@redhat.com>,
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "monitor/monitor.h"
+#include "qemu/qemu-print.h"
+
+/*
+ * Print like vprintf().
+ * Print to current monitor if we have one, else to stdout.
+ */
+int qemu_vprintf(const char *fmt, va_list ap)
+{
+    if (cur_mon) {
+        return monitor_vprintf(cur_mon, fmt, ap);
+    }
+    return vprintf(fmt, ap);
+}
+
+/*
+ * Print like printf().
+ * Print to current monitor if we have one, else to stdout.
+ */
+int qemu_printf(const char *fmt, ...)
+{
+    va_list ap;
+    int ret;
+
+    va_start(ap, fmt);
+    ret = qemu_vprintf(fmt, ap);
+    va_end(ap);
+    return ret;
+}