qemu-keymap: properly check return from xkb_keymap_mod_get_index

We can return XKB_MOD_INVALID for AltGr which rightly gets flagged by
sanitisers as an overly wide shift attempt. Properly check the return
type and leave the bitmap as zero in that case. Tested output before
and after is unchanged with the gb and ara keymaps.

Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20230630180423.558337-7-alex.bennee@linaro.org>

diff --git a/qemu-keymap.c b/qemu-keymap.c
index 229866e0044352595501a28fbd15527035963041..8c80f7a4ed6583bb044ba69e035920817bcd75e9 100644 (file)
--- a/qemu-keymap.c
+++ b/qemu-keymap.c
@@ -140,6 +140,18 @@ static void usage(FILE *out)
             names.options ?: "-");
 }
 
+static xkb_mod_mask_t get_mod(struct xkb_keymap *map, const char *name)
+{
+    xkb_mod_index_t mod;
+    xkb_mod_mask_t mask = 0;
+
+    mod = xkb_keymap_mod_get_index(map, name);
+    if (mod != XKB_MOD_INVALID) {
+        mask = (1 << mod);
+    }
+    return mask;
+}
+
 int main(int argc, char *argv[])
 {
     struct xkb_context *ctx;
@@ -215,14 +227,10 @@ int main(int argc, char *argv[])
                 mod, xkb_keymap_mod_get_name(map, mod));
     }
 
-    mod = xkb_keymap_mod_get_index(map, "Shift");
-    shift = (1 << mod);
-    mod = xkb_keymap_mod_get_index(map, "Control");
-    ctrl = (1 << mod);
-    mod = xkb_keymap_mod_get_index(map, "AltGr");
-    altgr = (1 << mod);
-    mod = xkb_keymap_mod_get_index(map, "NumLock");
-    numlock = (1 << mod);
+    shift = get_mod(map, "Shift");
+    ctrl = get_mod(map, "Control");
+    altgr = get_mod(map, "AltGr");
+    numlock = get_mod(map, "NumLock");
 
     state = xkb_state_new(map);
     xkb_keymap_key_for_each(map, walk_map, state);