macfb: fix a memory leak (CID 1465231)

Rewrite the function using g_string_append_printf() rather than
g_strdup_printf()/g_strconcat().

Fixes: df8abbbadf74 ("macfb: add common monitor modes supported by the MacOS toolbox ROM")
Cc: mark.cave-ayland@ilande.co.uk
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20211105165254.3544369-1-laurent@vivier.eu>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

1 files changed, 4 insertions, 7 deletions

diff --git a/hw/display/macfb.c b/hw/display/macfb.c
index 4b352eb..277d3e6 100644
--- a/hw/display/macfb.c
+++ b/hw/display/macfb.c
@@ -440,21 +440,18 @@ static MacFbMode *macfb_find_mode(MacfbDisplayType display_type,
 
 static gchar *macfb_mode_list(void)
 {
-    gchar *list = NULL;
-    gchar *mode;
+    GString *list = g_string_new("");
     MacFbMode *macfb_mode;
     int i;
 
     for (i = 0; i < ARRAY_SIZE(macfb_mode_table); i++) {
         macfb_mode = &macfb_mode_table[i];
 
-        mode = g_strdup_printf("    %dx%dx%d\n", macfb_mode->width,
+        g_string_append_printf(list, "    %dx%dx%d\n", macfb_mode->width,
                                macfb_mode->height, macfb_mode->depth);
-        list = g_strconcat(mode, list, NULL);
-        g_free(mode);
     }
 
-    return list;
+    return g_string_free(list, FALSE);
 }
 
 
@@ -643,7 +640,7 @@ static bool macfb_common_realize(DeviceState *dev, MacfbState *s, Error **errp)
         gchar *list;
         error_setg(errp, "unknown display mode: width %d, height %d, depth %d",
                    s->width, s->height, s->depth);
-        list =  macfb_mode_list();
+        list = macfb_mode_list();
         error_append_hint(errp, "Available modes:\n%s", list);
         g_free(list);