Fix code reviews

29 files changed, 524 insertions, 172 deletions

diff --git a/bus/ibusimpl.c b/bus/ibusimpl.c
index e432e849..49a138fe 100644
--- a/bus/ibusimpl.c
+++ b/bus/ibusimpl.c
@@ -2,8 +2,8 @@
 /* vim:set et sts=4: */
 /* ibus - The Input Bus
  * Copyright (C) 2008-2013 Peng Huang <shawn.p.huang@gmail.com>
- * Copyright (C) 2011-2020 Takao Fujiwara <takao.fujiwara1@gmail.com>
- * Copyright (C) 2008-2020 Red Hat, Inc.
+ * Copyright (C) 2011-2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
+ * Copyright (C) 2008-2021 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -624,7 +624,6 @@ bus_ibus_impl_destroy (BusIBusImpl *ibus)
 
     g_list_foreach (ibus->components, (GFunc) bus_component_stop, NULL);
 
-    pid = 0;
     timeout = 0;
     flag = FALSE;
     while (1) {
@@ -1190,6 +1189,7 @@ _ibus_get_current_input_context (BusIBusImpl     *ibus,
                                  GDBusConnection *connection,
                                  GError         **error)
 {
+    GVariant *retval = NULL;
     if (error) {
         *error = NULL;
     }
@@ -1204,8 +1204,14 @@ _ibus_get_current_input_context (BusIBusImpl     *ibus,
         const gchar *path = ibus_service_get_object_path (
                 (IBusService *) ibus->focused_context);
         /* the format-string 'o' is for a D-Bus object path. */
-        return g_variant_new_object_path (path);
+        retval = g_variant_new_object_path (path);
+        if (!retval) {
+            g_set_error (error, G_DBUS_ERROR, G_DBUS_ERROR_FAILED,
+                         "Could not get object path from %s",
+                         path ? path : "(null)");
+        }
     }
+    return retval;
 }
 
 static void
@@ -1572,6 +1578,7 @@ _ibus_get_global_engine (BusIBusImpl     *ibus,
                          GError         **error)
 {
     IBusEngineDesc *desc = NULL;
+    GVariant *retval = NULL;
 
     if (error) {
         *error = NULL;
@@ -1592,7 +1599,13 @@ _ibus_get_global_engine (BusIBusImpl     *ibus,
         GVariant *variant = ibus_serializable_serialize (
                 (IBusSerializable *) desc);
         // Set type "v" for introspection_xml.
-        return g_variant_new_variant (variant);
+        retval = g_variant_new_variant (variant);
+        if (!retval) {
+            g_set_error (error,
+                         G_DBUS_ERROR, G_DBUS_ERROR_FAILED,
+                         "Failed to serialize engine desc.");
+        }
+        return retval;
     } while (0);
 
     g_set_error (error,
diff --git a/bus/server.c b/bus/server.c
index 6c9e2c02..e8d0ce2b 100644
--- a/bus/server.c
+++ b/bus/server.c
@@ -2,8 +2,8 @@
 /* vim:set et sts=4: */
 /* bus - The Input Bus
  * Copyright (C) 2008-2010 Peng Huang <shawn.p.huang@gmail.com>
- * Copyright (C) 2011-2019 Takao Fujiwara <takao.fujiwara1@gmail.com>
- * Copyright (C) 2008-2019 Red Hat, Inc.
+ * Copyright (C) 2011-2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
+ * Copyright (C) 2008-2021 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -22,12 +22,11 @@
  */
 #include "server.h"
 
-#include <errno.h>
 #include <glib/gstdio.h>
 #include <gio/gio.h>
-#include <stdlib.h>
-#include <fcntl.h>
 #include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
 #include <string.h>
 
 #include "dbusimpl.h"
@@ -282,6 +281,7 @@ bus_server_init (void)
          * `chmod` runs for the last directory only not to change the modes
          * of the parent directories. E.g. "/tmp/ibus".
          */
+        errno = 0;
         if (g_mkdir_with_parents (unix_dir, 0700) != 0) {
             g_error ("mkdir is failed in: %s: %s",
                      unix_dir, g_strerror (errno));
diff --git a/client/gtk2/ibusimcontext.c b/client/gtk2/ibusimcontext.c
index 61194816..e7ce5363 100644
--- a/client/gtk2/ibusimcontext.c
+++ b/client/gtk2/ibusimcontext.c
@@ -385,7 +385,9 @@ _process_key_event_done (GObject      *object,
 
     ProcessKeyEventData *data = (ProcessKeyEventData *)user_data;
     GdkEvent *event = data->event;
+#if GTK_CHECK_VERSION (3, 98, 4)
     IBusIMContext *ibusimcontext = data->ibusimcontext;
+#endif
     GError *error = NULL;
 
     g_slice_free (ProcessKeyEventData, data);
@@ -1634,6 +1636,7 @@ get_selection_anchor_point (IBusIMContext *ibusimcontext,
     return anchor;
 }
 
+#if !GTK_CHECK_VERSION (4, 1, 2)
 static void
 ibus_im_context_set_surrounding (GtkIMContext  *context,
                                  const gchar   *text,
@@ -1646,6 +1649,7 @@ ibus_im_context_set_surrounding (GtkIMContext  *context,
                                                     cursor_index,
                                                     cursor_index);
 }
+#endif
 
 static void
 ibus_im_context_set_surrounding_with_selection (GtkIMContext  *context,
@@ -1851,7 +1855,11 @@ _create_gdk_event (IBusIMContext *ibusimcontext,
         if (event->state & GDK_CONTROL_MASK) {
             if ((c >= '@' && c < '\177') || c == ' ') c &= 0x1F;
             else if (c == '2') {
+#if GLIB_CHECK_VERSION (2, 68, 0)
+                event->string = g_memdup2 ("\0\0", 2);
+#else
                 event->string = g_memdup ("\0\0", 2);
+#endif
                 event->length = 1;
                 buf[0] = '\0';
                 goto out;
diff --git a/client/wayland/main.c b/client/wayland/main.c
index d86bab9e..1f99c804 100644
--- a/client/wayland/main.c
+++ b/client/wayland/main.c
@@ -1,7 +1,7 @@
 /* -*- mode: C; c-basic-offset: 4; indent-tabs-mode: nil; -*- */
 /* vim:set et sts=4: */
 /* ibus - The Input Bus
- * Copyright (C) 2019 Takao Fujiwara <takao.fujiwara1@gmail.com>
+ * Copyright (C) 2019-2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  * Copyright (C) 2013 Intel Corporation
  * Copyright (C) 2013-2019 Red Hat, Inc.
  *
@@ -339,16 +339,19 @@ input_method_keyboard_keymap (void               *data,
 {
     IBusWaylandIM *wlim = data;
     GMappedFile *map;
-    GError *error;
+    GError *error = NULL;
 
     if (format != WL_KEYBOARD_KEYMAP_FORMAT_XKB_V1) {
         close(fd);
         return;
     }
 
-    error = NULL;
     map = g_mapped_file_new_from_fd (fd, FALSE, &error);
     if (map == NULL) {
+        if (error) {
+            g_warning ("Failed to map file fd %s", error->message);
+            g_error_free (error);
+        }
         close (fd);
         return;
     }
diff --git a/client/x11/main.c b/client/x11/main.c
index c9ee174d..ffd776fd 100644
--- a/client/x11/main.c
+++ b/client/x11/main.c
@@ -2,7 +2,7 @@
 /* vim:set et sts=4: */
 /* ibus
  * Copyright (C) 2007-2015 Peng Huang <shawn.p.huang@gmail.com>
- * Copyright (C) 2015-2019 Takao Fujiwara <takao.fujiwara1@gmail.com>
+ * Copyright (C) 2015-2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  * Copyright (C) 2007-2015 Red Hat, Inc.
  *
  * main.c:
@@ -229,12 +229,13 @@ _xim_preedit_callback_draw (XIMS xims, X11IC *x11ic, const gchar *preedit_string
         }
     }
 
-    for (i = 0; i < len; i++) {
+    for (i = 0; feedback && i < len; i++) {
         if (feedback[i] == 0) {
             feedback[i] = XIMUnderline;
         }
     }
-    feedback[len] = 0;
+    if (feedback)
+        feedback[len] = 0;
 
     pcb.major_code = XIM_PREEDIT_DRAW;
     pcb.connect_id = x11ic->connect_id;
@@ -736,9 +737,20 @@ xim_get_ic_values (XIMS xims, IMChangeICStruct *call_data)
 
     for (i = 0; i < (int) call_data->ic_attr_num; ++i, ++ic_attr) {
         if (g_strcmp0 (XNFilterEvents, ic_attr->name) == 0) {
+            /* ic_attr->value will be freed in server side and ignore
+             * leak of malloc with -Wanalyzer-malloc-leak flags in gcc 11.0.1
+             */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wanalyzer-malloc-leak"
             ic_attr->value = (void *) malloc (sizeof (CARD32));
-            *(CARD32 *) ic_attr->value = KeyPressMask | KeyReleaseMask;
-            ic_attr->value_length = sizeof (CARD32);
+            if (ic_attr->value) {
+                *(CARD32 *) ic_attr->value = KeyPressMask | KeyReleaseMask;
+                ic_attr->value_length = sizeof (CARD32);
+            } else {
+                g_warning ("Failed to malloc");
+                ic_attr->value_length = 0;
+            }
+#pragma GCC diagnostic pop
         }
     }
 
diff --git a/conf/dconf/main.c b/conf/dconf/main.c
index e6878424..c8250f68 100644
--- a/conf/dconf/main.c
+++ b/conf/dconf/main.c
@@ -2,7 +2,8 @@
 /* vim:set et sts=4: */
 /* ibus - The Input Bus
  * Copyright (C) 2008-2010 Peng Huang <shawn.p.huang@gmail.com>
- * Copyright (C) 2008-2010 Red Hat, Inc.
+ * Copyright (C) 2012-2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
+ * Copyright (C) 2008-2021 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -70,7 +71,9 @@ main (gint argc, gchar **argv)
     GOptionContext *context;
 
     setlocale (LC_ALL, "");
-    g_setenv ("DCONF_PROFILE", "ibus", FALSE);
+    errno = 0;
+    if (!g_setenv ("DCONF_PROFILE", "ibus", FALSE))
+        g_warning ("Failed setenv %s", strerror (errno));
 
     context = g_option_context_new ("- ibus dconf component");
 
diff --git a/portal/portal.c b/portal/portal.c
index e78bc92f..c2e4fc7f 100644
--- a/portal/portal.c
+++ b/portal/portal.c
@@ -1,7 +1,7 @@
 /* -*- mode: C; c-basic-offset: 4; indent-tabs-mode: nil; -*- */
 /* vim:set et sts=4: */
 /* ibus - The Input Bus
- * Copyright (C) 2017-2019 Red Hat, Inc.
+ * Copyright (C) 2017-2021 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -508,7 +508,6 @@ create_input_context_done (IBusBus               *bus,
     if (portal_context == NULL) {
         g_dbus_method_invocation_return_gerror (invocation, error);
         g_error_free (error);
-        g_object_unref (portal_context);
         return;
     }
 
@@ -656,8 +655,10 @@ main (gint argc, gchar **argv)
         exit (-1);
     }
 
+     errno = 0;
     /* Avoid even loading gvfs to avoid accidental confusion */
-    g_setenv ("GIO_USE_VFS", "local", TRUE);
+    if (!g_setenv ("GIO_USE_VFS", "local", TRUE))
+        g_warning ("Failed setenv %s", strerror (errno));
 
     ibus_init ();
 
diff --git a/setup/ibus-setup.in b/setup/ibus-setup.in
index 4a6830af..474ce8a8 100644
--- a/setup/ibus-setup.in
+++ b/setup/ibus-setup.in
@@ -27,5 +27,5 @@ export IBUS_PREFIX=@prefix@
 export IBUS_DATAROOTDIR=@datarootdir@
 export IBUS_LOCALEDIR=@localedir@
 export IBUS_LIBEXECDIR=${libexecdir}
-exec ${PYTHON:-@PYTHON@} @prefix@/share/ibus/setup/main.py $@
+exec ${PYTHON:-@PYTHON@} @prefix@/share/ibus/setup/main.py "$@"
 
diff --git a/src/emoji-parser.c b/src/emoji-parser.c
index b117b1b4..36d36e05 100644
--- a/src/emoji-parser.c
+++ b/src/emoji-parser.c
@@ -1,7 +1,7 @@
 /* -*- mode: C; c-basic-offset: 4; indent-tabs-mode: nil; -*- */
 /* vim:set et sts=4: */
 /* ibus - The Input Bus
- * Copyright (C) 2016-2020 Takao Fujiwara <takao.fujiwara1@gmail.com>
+ * Copyright (C) 2016-2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  * Copyright (C) 2016 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
@@ -291,11 +291,9 @@ emoji_data_new_object (EmojiData *data)
                                  "annotations",
                                  data->annotations,
                                  "description",
-                                 data->description ? data->description
-                                         : g_strdup (""),
+                                 data->description ? data->description : "",
                                  "category",
-                                 data->category ? data->category
-                                         : g_strdup (""),
+                                 data->category ? data->category : "",
                                  NULL);
     data->list = g_slist_append (data->list, emoji);
 }
@@ -608,7 +606,7 @@ unicode_emoji_test_parse_line (const gchar *line,
         return FALSE;
     }
     unicode_emoji_test_parse_description (segments[1], data);
-    g_strfreev (segments);
+    g_clear_pointer (&segments, g_strfreev);
     if (data->annotations == NULL) {
         if (data->subcategory) {
             int i;
@@ -631,7 +629,7 @@ unicode_emoji_test_parse_line (const gchar *line,
                 data->annotations = g_slist_append (data->annotations,
                                                     g_strdup (segments[i]));
             }
-            g_strfreev (segments);
+            g_clear_pointer (&segments, g_strfreev);
         } else {
             g_warning ("No subcategory line\n");
             goto failed_to_parse_unicode_emoji_test_line;
@@ -672,7 +670,7 @@ unicode_emoji_test_parse_file (const gchar *filename,
                    filename, error ? error->message : "");
         goto failed_to_parse_unicode_emoji_test;
     }
-    head = end = content;
+    end = content;
     while (*end == '\n' && end - content < length) {
         end++;
         n++;
@@ -1100,10 +1098,12 @@ static void
 category_list_dump (const gchar *category,
                     GString     *buff)
 {
+    gchar *line;
     g_return_if_fail (buff != NULL);
 
-    const gchar *line = g_strdup_printf ("    N_(\"%s\"),\n", category);
+    line = g_strdup_printf ("    N_(\"%s\"),\n", category);
     g_string_append (buff, line);
+    g_free (line);
 }
 
 static void
@@ -1113,7 +1113,7 @@ category_file_save (const gchar *filename,
     gchar *content = NULL;
     gsize length = 0;
     GError *error = NULL;
-    gchar *p;
+    gchar *p, *substr;
     GString *buff = NULL;
     int i;
     GSList *list_categories = NULL;
@@ -1139,24 +1139,28 @@ category_file_save (const gchar *filename,
             break;
     }
     if (p != NULL) {
-        g_string_append (buff, g_strndup (content, p - content));
+        substr = g_strndup (content, p - content);
+        g_string_append (buff, substr);
+        g_free (substr);
         g_string_append_c (buff, '\n');
     }
     g_clear_pointer (&content, g_free);
 
-    g_string_append (buff, g_strdup ("\n"));
-    g_string_append (buff, g_strdup_printf ("/* This file is generated by %s. */", __FILE__));
-    g_string_append (buff, g_strdup ("\n"));
-    g_string_append (buff, g_strdup ("include <glib/gi18n.h>\n"));
-    g_string_append (buff, g_strdup ("\n"));
-    g_string_append (buff, g_strdup ("#ifndef __IBUS_EMOJI_GEN_H_\n"));
-    g_string_append (buff, g_strdup ("#define __IBUS_EMOJI_GEN_H_\n"));
-    g_string_append (buff, g_strdup ("const static char *unicode_emoji_categories[] = {\n"));
+    g_string_append (buff, "\n");
+    substr = g_strdup_printf ("/* This file is generated by %s. */", __FILE__);
+    g_string_append (buff, substr);
+    g_free (substr);
+    g_string_append (buff, "\n");
+    g_string_append (buff, "include <glib/gi18n.h>\n");
+    g_string_append (buff, "\n");
+    g_string_append (buff, "#ifndef __IBUS_EMOJI_GEN_H_\n");
+    g_string_append (buff, "#define __IBUS_EMOJI_GEN_H_\n");
+    g_string_append (buff, "const static char *unicode_emoji_categories[] = {\n");
     list_categories = g_slist_sort (list_categories, (GCompareFunc)g_strcmp0);
     g_slist_foreach (list_categories, (GFunc)category_list_dump, buff);
     g_slist_free (list_categories);
-    g_string_append (buff, g_strdup ("};\n"));
-    g_string_append (buff, g_strdup ("#endif\n"));
+    g_string_append (buff, "};\n");
+    g_string_append (buff, "#endif\n");
 
     if (!g_file_set_contents (filename, buff->str, -1, &error)) {
         g_warning ("Failed to save emoji category file %s: %s", filename, error->message);
diff --git a/src/ibusaccelgroup.c b/src/ibusaccelgroup.c
index 8a81597e..ef2d3976 100644
--- a/src/ibusaccelgroup.c
+++ b/src/ibusaccelgroup.c
@@ -468,7 +468,7 @@ ibus_accelerator_name (guint            accelerator_key,
     if (accelerator_mods & IBUS_SUPER_MASK)
         l += sizeof (text_super) - 1;
 
-    accelerator = g_new (gchar, l + 1);
+    g_return_val_if_fail ((accelerator = g_new (gchar, l + 1)), NULL);
 
     accelerator_mods = saved_mods;
     l = 0;
diff --git a/src/ibusbus.c b/src/ibusbus.c
index b7ffbb47..e9b0bcbb 100644
--- a/src/ibusbus.c
+++ b/src/ibusbus.c
@@ -2,7 +2,7 @@
 /* vim:set et sts=4: */
 /* ibus - The Input Bus
  * Copyright (C) 2008-2015 Peng Huang <shawn.p.huang@gmail.com>
- * Copyright (C) 2015-2019 Takao Fujiwara <takao.fujiwara1@gmail.com>
+ * Copyright (C) 2015-2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  * Copyright (C) 2008-2016 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
@@ -555,12 +555,18 @@ ibus_bus_init (IBusBus *bus)
 
     path = g_path_get_dirname (ibus_get_socket_path ());
 
-    g_mkdir_with_parents (path, 0700);
+    errno = 0;
+    if (g_mkdir_with_parents (path, 0700)) {
+        g_warning ("Failed to mkdir %s: %s", path, g_strerror (errno));
+        g_free (path);
+        return;
+    }
 
     if (stat (path, &buf) == 0) {
         if (buf.st_uid != getuid ()) {
             g_warning ("The owner of %s is not %s!",
                        path, ibus_get_user_name ());
+            g_free (path);
             return;
         }
         if (buf.st_mode != (S_IFDIR | S_IRWXU)) {
diff --git a/src/ibuscomposetable.c b/src/ibuscomposetable.c
index ef20469c..685ac717 100644
--- a/src/ibuscomposetable.c
+++ b/src/ibuscomposetable.c
@@ -1,7 +1,7 @@
 /* -*- mode: C; c-basic-offset: 4; indent-tabs-mode: nil; -*- */
 /* ibus - The Input Bus
  * Copyright (C) 2013-2014 Peng Huang <shawn.p.huang@gmail.com>
- * Copyright (C) 2013-2019 Takao Fujiwara <takao.fujiwara1@gmail.com>
+ * Copyright (C) 2013-2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -108,6 +108,7 @@ parse_compose_value (IBusComposeData  *compose_data,
     }
     ++head;
     p = head;
+    end = NULL;
     while ((*p != '\0') && (end = strchr (p, '\"'))) {
         if (*(end - 1) == '\\' && *(end - 2) == '\\')
             break;
@@ -516,10 +517,10 @@ ibus_compose_hash_get_cache_path (guint32 hash)
                                 "ibus", "compose", NULL);
     }
     path = g_build_filename (dir, basename, NULL);
-    if (g_mkdir_with_parents (dir, 0755) != 0) {
-        g_warning ("Failed to mkdir %s", dir);
-        g_free (path);
-        path = NULL;
+    errno = 0;
+    if (g_mkdir_with_parents (dir, 0755)) {
+        g_warning ("Failed to mkdir %s: %s", dir, g_strerror (errno));
+        g_clear_pointer (&path, g_free);
     }
 
     g_free (dir);
@@ -812,10 +813,14 @@ ibus_compose_table_deserialize (const gchar *contents,
         }
     }
     if (data_length) {
-        retval->priv->data_second = g_new (guint32, data_length);
-        memcpy (retval->priv->data_second,
-                data_32bit_second, data_length * sizeof (guint32));
-        retval->priv->second_size = second_size;
+        if ((retval->priv->data_second = g_new (guint32, data_length))) {
+            memcpy (retval->priv->data_second,
+                    data_32bit_second, data_length * sizeof (guint32));
+            retval->priv->second_size = second_size;
+        } else {
+            g_warning ("Failed g_new");
+            retval->priv->second_size = 0;
+        }
     }
 
 
@@ -910,6 +915,43 @@ ibus_compose_table_new_with_list (GList   *compose_list,
                                   int      n_index_stride,
                                   guint32  hash)
 {
+    /* @ibus_compose_seqs: Include both compose sequence and the value(compose
+     *     output) as the tradition GTK. The value is one character only
+     *     and within 16bit. I.e. All compose sequences and the values
+     *     are 16bit.
+     * @ibus_compose_seqs_32bit_second: Include the compose values only.
+     *     The length of values by compose sequence is more than one characster
+     *     or one of the values is outside 16bit but within 32bit.
+     *     Some values could be more than one character and Emoji character
+     *     could be outside 16bit.
+     *     See also ibus/src/tests/ibus-compose.emoji file for e.g.
+     * @ibus_compose_seqs_32bit_first: Include the compose sequence only in
+     *     case the value is included in @ibus_compose_seqs_32bit_second.
+     * @s_size_total: The number of compose sequences.
+     * @s_size_16bit: The number of compose sequences whose value is one
+     *     character only and within 16bit. I.e. the number of the compose
+     *     sequence in @ibus_compose_seqs is @@s_size_16bit. And
+     *     @s_size_total - @s_size_16bit is the number of the compose sequence
+     *     in @ibus_compose_seqs_32bit_first.
+     * @v_size_32bit: The total number of compose values. Each length of the
+     *     values is more than one character or one of the value is
+     *     outside 16bit but within 32bit. I.e. The size of
+     *     @ibus_compose_seqs_32bit_second is @v_size_32bit.
+     * @v_index_32bit: Each index of the compose values in
+     *     @ibus_compose_seqs_32bit_second and this is not a fixed value in
+     *     this API. If a compose sequence is found in
+     *     @ibus_compose_seqs_32bit_first and the next value is 0, 0 is lined
+     *     in @ibus_compose_seqs_32bit_first until @max_compose_len after
+     *     the found compose sequence. And the next value is the length of
+     *     the compose values and the next value is the @v_index_32bit, i.e.
+     *     the index of @ibus_compose_seqs_32bit_second.
+     *     E.g. the following line could be found in
+     *     @ibus_compose_seqs_32bit_first:
+     *         ..., "U17ff", "0", "0", "0", "0", 2, 100, ...
+     *     @ibus_compose_seqs_32bit_second[100] is "ាំ"  and the character
+     *     length is 2.
+     *     @max_compose_len is 5 and @n_index_stride is 7.
+     */
     gsize s_size_total, s_size_16bit, v_size_32bit, v_index_32bit;
     guint n = 0, m = 0;
     int i, j;
@@ -935,13 +977,25 @@ ibus_compose_table_new_with_list (GList   *compose_list,
         }
     }
 
-    if (s_size_16bit)
+    if (s_size_16bit) {
         ibus_compose_seqs = g_new (guint16, s_size_16bit * n_index_stride);
+        if (!ibus_compose_seqs) {
+            g_warning ("Failed g_new");
+            return NULL;
+        }
+    }
     if (s_size_total > s_size_16bit) {
         ibus_compose_seqs_32bit_first =
                 g_new (guint16,
                        (s_size_total - s_size_16bit) * n_index_stride);
         ibus_compose_seqs_32bit_second = g_new (guint32, v_size_32bit);
+        if (!ibus_compose_seqs_32bit_first || !ibus_compose_seqs_32bit_second) {
+            g_warning ("Failed g_new");
+            g_free (ibus_compose_seqs);
+            g_free (ibus_compose_seqs_32bit_first);
+            g_free (ibus_compose_seqs_32bit_second);
+            return NULL;
+        }
     }
 
     v_index_32bit = 0;
@@ -951,32 +1005,45 @@ ibus_compose_table_new_with_list (GList   *compose_list,
 
         is_32bit = unichar_length (compose_data->values) > 1 ? TRUE :
                 compose_data->values[0] >= 0xFFFF ? TRUE : FALSE;
+        if (is_32bit) {
+            g_assert (ibus_compose_seqs_32bit_first);
+            g_assert (ibus_compose_seqs_32bit_second);
+        }
         for (i = 0; i < max_compose_len; i++) {
             if (compose_data->sequence[i] == 0) {
                 for (j = i; j < max_compose_len; j++) {
-                    if (is_32bit)
+                    if (is_32bit) {
+                        g_assert (m < (s_size_total - s_size_16bit)
+                                  * n_index_stride);
                         ibus_compose_seqs_32bit_first[m++] = 0;
-                    else
+                    } else {
+                        g_assert (n < s_size_16bit * n_index_stride);
                         ibus_compose_seqs[n++] = 0;
+                    }
                 }
                 break;
             }
             if (is_32bit) {
+                g_assert (m < (s_size_total - s_size_16bit) * n_index_stride);
                 ibus_compose_seqs_32bit_first[m++] =
                         (guint16) compose_data->sequence[i];
             } else {
+                g_assert (n < s_size_16bit * n_index_stride);
                 ibus_compose_seqs[n++] = (guint16) compose_data->sequence[i];
             }
         }
         if (is_32bit) {
             for (j = 0; compose_data->values[j]; j++) {
+                g_assert (v_index_32bit + j <  v_size_32bit);
                 ibus_compose_seqs_32bit_second[v_index_32bit + j] =
                         compose_data->values[j];
             }
+            g_assert (m + 1 < (s_size_total - s_size_16bit) * n_index_stride);
             ibus_compose_seqs_32bit_first[m++] = j;
             ibus_compose_seqs_32bit_first[m++] = v_index_32bit;
             v_index_32bit += j;
         } else {
+            g_assert (n + 1 < s_size_16bit * n_index_stride);
             ibus_compose_seqs[n++] = (guint16) compose_data->values[0];
             ibus_compose_seqs[n++] = 0;
         }
diff --git a/src/ibusemoji.c b/src/ibusemoji.c
index ae8907a2..df97264b 100644
--- a/src/ibusemoji.c
+++ b/src/ibusemoji.c
@@ -1,7 +1,7 @@
 /* -*- mode: C; c-basic-offset: 4; indent-tabs-mode: nil; -*- */
 /* vim:set et sts=4: */
 /* bus - The Input Bus
- * Copyright (C) 2017-2019 Takao Fujiwara <takao.fujiwara1@gmail.com>
+ * Copyright (C) 2017-2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  * Copyright (C) 2017-2019 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
@@ -497,7 +497,11 @@ ibus_emoji_data_save (const gchar *path,
 
     dir = g_path_get_dirname (path);
     if (g_strcmp0 (dir, ".") != 0 && g_stat (dir, &buf) != 0) {
-        g_mkdir_with_parents (dir, 0777);
+        errno = 0;
+        if (g_mkdir_with_parents (dir, 0777)) {
+            g_warning ("Failed mkdir %s: %s", dir, g_strerror (errno));
+            return;
+        }
     }
     g_free (dir);
     if (!g_file_set_contents (path, contents, length, &error)) {
diff --git a/src/ibusenginesimple.c b/src/ibusenginesimple.c
index 43bd5283..6dbc39c7 100644
--- a/src/ibusenginesimple.c
+++ b/src/ibusenginesimple.c
@@ -2,7 +2,7 @@
 /* vim:set et sts=4: */
 /* ibus - The Input Bus
  * Copyright (C) 2014 Peng Huang <shawn.p.huang@gmail.com>
- * Copyright (C) 2015-2019 Takao Fujiwara <takao.fujiwara1@gmail.com>
+ * Copyright (C) 2015-2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  * Copyright (C) 2014-2017 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
@@ -466,11 +466,15 @@ check_hex (IBusEngineSimple *simple,
 
         ch = ibus_keyval_to_unicode (priv->compose_buffer[i]);
 
-        if (ch == 0)
+        if (ch == 0) {
+            g_string_free (str, TRUE);
             return FALSE;
+        }
 
-        if (!g_unichar_isxdigit (ch))
+        if (!g_unichar_isxdigit (ch)) {
+            g_string_free (str, TRUE);
             return FALSE;
+        }
 
         buf[g_unichar_to_utf8 (ch, buf)] = '\0';
 
@@ -487,8 +491,9 @@ check_hex (IBusEngineSimple *simple,
     if (nptr - str->str < str->len) {
         g_string_free (str, TRUE);
         return FALSE;
-    } else
+    } else {
         g_string_free (str, TRUE);
+    }
 
     if (g_unichar_validate (n)) {
         priv->tentative_match = n;
@@ -559,11 +564,15 @@ check_emoji_table (IBusEngineSimple       *simple,
 
         ch = ibus_keyval_to_unicode (priv->compose_buffer[i]);
 
-        if (ch == 0)
+        if (ch == 0) {
+            g_string_free (str, TRUE);
             return FALSE;
+        }
 
-        if (!g_unichar_isprint (ch))
+        if (!g_unichar_isprint (ch)) {
+            g_string_free (str, TRUE);
             return FALSE;
+        }
 
         buf[g_unichar_to_utf8 (ch, buf)] = '\0';
 
diff --git a/src/ibushotkey.c b/src/ibushotkey.c
index d4ab7c23..e72b8305 100644
--- a/src/ibushotkey.c
+++ b/src/ibushotkey.c
@@ -2,7 +2,7 @@
 /* vim:set et sts=4: */
 /* IBus - The Input Bus
  * Copyright (C) 2008-2010 Peng Huang <shawn.p.huang@gmail.com>
- * Copyright (C) 2018-2019 Takao Fujiwara <takao.fujiwara1@gmail.com>
+ * Copyright (C) 2018-2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  * Copyright (C) 2008-2019 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
@@ -373,6 +373,8 @@ ibus_hotkey_profile_add_hotkey (IBusHotkeyProfile *profile,
         p->event = event;
     }
 
+    if (!p)
+        return FALSE;
     p->hotkeys = g_list_append (p->hotkeys, hotkey);
 
     return TRUE;
diff --git a/src/ibusregistry.c b/src/ibusregistry.c
index 3386a5d1..23c5ca1b 100644
--- a/src/ibusregistry.c
+++ b/src/ibusregistry.c
@@ -2,7 +2,7 @@
 /* vim:set et sts=4: */
 /* bus - The Input Bus
  * Copyright (C) 2015 Peng Huang <shawn.p.huang@gmail.com>
- * Copyright (C) 2015-2020 Takao Fujiwara <takao.fujiwara1@gmail.com>
+ * Copyright (C) 2015-2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  * Copyright (C) 2015-2020 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
@@ -438,7 +438,12 @@ ibus_registry_save_cache_file (IBusRegistry *registry,
     g_assert (filename != NULL);
 
     cachedir = g_path_get_dirname (filename);
-    g_mkdir_with_parents (cachedir, 0775);
+    errno = 0;
+    if (g_mkdir_with_parents (cachedir, 0775)) {
+        g_warning ("Failed to mkdir %s: %s", cachedir, g_strerror (errno));
+        g_free (cachedir);
+        return FALSE;
+    }
     g_free (cachedir);
 
     variant = ibus_serializable_serialize (IBUS_SERIALIZABLE (registry));
diff --git a/src/ibusshare.c b/src/ibusshare.c
index e0ef2ce0..8974511a 100644
--- a/src/ibusshare.c
+++ b/src/ibusshare.c
@@ -2,7 +2,7 @@
 /* vim:set et sts=4: */
 /* ibus - The Input Bus
  * Copyright (C) 2008-2010 Peng Huang <shawn.p.huang@gmail.com>
- * Copyright (C) 2015-2018 Takao Fujiwara <takao.fujiwara1@gmail.com>
+ * Copyright (C) 2015-2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  * Copyright (C) 2008-2018 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
@@ -197,22 +197,17 @@ ibus_get_address (void)
     FILE *pf;
 
     /* free address */
-    if (address != NULL) {
-        g_free (address);
-        address = NULL;
-    }
+    g_clear_pointer (&address, g_free);
 
     /* get address from env variable */
     address = g_strdup (g_getenv ("IBUS_ADDRESS"));
-    if (address) {
+    if (address)
         return address;
-    }
 
     /* read address from ~/.config/ibus/bus/soketfile */
     pf = fopen (ibus_get_socket_path (), "r");
-    if (pf == NULL) {
+    if (pf == NULL)
         return NULL;
-    }
 
     while (!feof (pf)) {
         gchar *p = buffer;
@@ -224,11 +219,12 @@ ibus_get_address (void)
             continue;
         /* parse IBUS_ADDRESS */
         if (strncmp (p, "IBUS_ADDRESS=", sizeof ("IBUS_ADDRESS=") - 1) == 0) {
-            address = p + sizeof ("IBUS_ADDRESS=") - 1;
-            for (p = (gchar *)address; *p != '\n' && *p != '\0'; p++);
+            gchar *head = p + sizeof ("IBUS_ADDRESS=") - 1;
+            for (p = head; *p != '\n' && *p != '\0'; p++);
             if (*p == '\n')
                 *p = '\0';
-            address = g_strdup (address);
+            g_free (address);
+            address = g_strdup (head);
             continue;
         }
 
@@ -241,9 +237,8 @@ ibus_get_address (void)
     }
     fclose (pf);
 
-    if (pid == -1 || kill (pid, 0) != 0) {
+    if (pid == -1 || kill (pid, 0) != 0)
         return NULL;
-    }
 
     return address;
 }
@@ -256,10 +251,19 @@ ibus_write_address (const gchar *address)
     g_return_if_fail (address != NULL);
 
     path = g_path_get_dirname (ibus_get_socket_path ());
-    g_mkdir_with_parents (path, 0700);
+    errno = 0;
+    if (g_mkdir_with_parents (path, 0700)) {
+        g_warning ("Failed to mkdir %s: %s", path, g_strerror (errno));
+        g_free (path);
+        return;
+    }
     g_free (path);
 
-    g_unlink (ibus_get_socket_path ());
+    errno = 0;
+    if (g_unlink (ibus_get_socket_path ())) {
+        g_warning ("Failed to unlink %s: %s",
+                   ibus_get_socket_path (), g_strerror (errno));
+    }
     pf = fopen (ibus_get_socket_path (), "w");
     g_return_if_fail (pf != NULL);
 
diff --git a/src/ibustext.c b/src/ibustext.c
index a5e3c43b..ed0fe666 100644
--- a/src/ibustext.c
+++ b/src/ibustext.c
@@ -2,7 +2,8 @@
 /* vim:set et sts=4: */
 /* IBus - The Input Bus
  * Copyright (C) 2008-2010 Peng Huang <shawn.p.huang@gmail.com>
- * Copyright (C) 2008-2010 Red Hat, Inc.
+ * Copyright (C) 2011-2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
+ * Copyright (C) 2008-2021 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -220,7 +221,7 @@ ibus_text_new_from_unichar (gunichar c)
     text= g_object_new (IBUS_TYPE_TEXT, NULL);
 
     text->is_static = FALSE;
-    text->text = (gchar *)g_malloc (12);
+    g_return_val_if_fail ((text->text = (gchar *)g_malloc (12)), NULL);
     len = g_unichar_to_utf8 (c, text->text);
     text->text[len] =  0;
 
diff --git a/src/ibusunicode.c b/src/ibusunicode.c
index 9e6f6b2b..f7a897d1 100644
--- a/src/ibusunicode.c
+++ b/src/ibusunicode.c
@@ -1,8 +1,8 @@
 /* -*- mode: C; c-basic-offset: 4; indent-tabs-mode: nil; -*- */
 /* vim:set et sts=4: */
 /* bus - The Input Bus
- * Copyright (C) 2018-2019 Takao Fujiwara <takao.fujiwara1@gmail.com>
- * Copyright (C) 2018-2019 Red Hat, Inc.
+ * Copyright (C) 2018-2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
+ * Copyright (C) 2018-2021 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -472,7 +472,12 @@ ibus_unicode_data_save (const gchar *path,
 
     dir = g_path_get_dirname (path);
     if (g_strcmp0 (dir, ".") != 0 && g_stat (dir, &buf) != 0) {
-        g_mkdir_with_parents (dir, 0777);
+        errno = 0;
+        if (g_mkdir_with_parents (dir, 0777)) {
+            g_warning ("Failed to mkdir %s: %s", dir, g_strerror (errno));
+            return;
+        }
+
     }
     g_free (dir);
     if (!g_file_set_contents (path, contents, length, &error)) {
@@ -967,7 +972,11 @@ ibus_unicode_block_save (const gchar *path,
 
     dir = g_path_get_dirname (path);
     if (g_strcmp0 (dir, ".") != 0 && g_stat (dir, &buf) != 0) {
-        g_mkdir_with_parents (dir, 0777);
+        errno = 0;
+        if (g_mkdir_with_parents (dir, 0777)) {
+            g_warning ("Failed to mkdir %s: %s", dir, g_strerror (errno));
+            return;
+        }
     }
     g_free (dir);
     if (!g_file_set_contents (path, contents, length, &error)) {
diff --git a/src/tests/ibus-compose.c b/src/tests/ibus-compose.c
index 4b4c56e7..81bfc69b 100644
--- a/src/tests/ibus-compose.c
+++ b/src/tests/ibus-compose.c
@@ -360,11 +360,13 @@ main (int argc, char *argv[])
     /* Avoid a warning of "AT-SPI: Could not obtain desktop path or name"
      * with gtk_main().
      */
-    g_setenv ("NO_AT_BRIDGE", "1", TRUE);
+    if (!g_setenv ("NO_AT_BRIDGE", "1", TRUE))
+        g_message ("Failed setenv NO_AT_BRIDGE\n");
     g_test_init (&argc, &argv, NULL);
     gtk_init (&argc, &argv);
 
-    m_srcdir = argc > 1 ? g_strdup (argv[1]) : g_strdup (".");
+    m_srcdir = (argc > 1 && strlen (argv[1]) < FILENAME_MAX)
+            ? g_strdup (argv[1]) : g_strdup (".");
     m_compose_file = g_strdup (g_getenv ("COMPOSE_FILE"));
 #if GLIB_CHECK_VERSION (2, 58, 0)
     test_name = g_get_language_names_with_category ("LC_CTYPE")[0];
diff --git a/src/tests/ibus-keypress.c b/src/tests/ibus-keypress.c
index dd1b0042..bab05398 100644
--- a/src/tests/ibus-keypress.c
+++ b/src/tests/ibus-keypress.c
@@ -291,7 +291,8 @@ main (int argc, char *argv[])
     /* Avoid a warning of "AT-SPI: Could not obtain desktop path or name"
      * with gtk_main().
      */
-    g_setenv ("NO_AT_BRIDGE", "1", TRUE);
+    if (!g_setenv ("NO_AT_BRIDGE", "1", TRUE))
+        g_message ("Failed setenv NO_AT_BRIDGE\n");
     g_test_init (&argc, &argv, NULL);
     gtk_init (&argc, &argv);
 
diff --git a/src/unicode-parser.c b/src/unicode-parser.c
index b4303ea8..2c4eb677 100644
--- a/src/unicode-parser.c
+++ b/src/unicode-parser.c
@@ -1,8 +1,8 @@
 /* -*- mode: C; c-basic-offset: 4; indent-tabs-mode: nil; -*- */
 /* vim:set et sts=4: */
 /* ibus - The Input Bus
- * Copyright (C) 2018 Takao Fujiwara <takao.fujiwara1@gmail.com>
- * Copyright (C) 2018 Red Hat, Inc.
+ * Copyright (C) 2018-2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
+ * Copyright (C) 2018-2021 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -76,11 +76,9 @@ unicode_data_new_object (UnicodeData *data)
             ibus_unicode_data_new ("code",
                                    data->code,
                                    "name",
-                                   data->name ? g_strdup (data->name)
-                                           : g_strdup (""),
+                                   data->name ? data->name : "",
                                    "alias",
-                                   data->alias ? g_strdup (data->alias)
-                                           : g_strdup (""),
+                                   data->alias ? data->alias : "",
                                    NULL);
     data->list = g_slist_append (data->list, unicode);
 }
@@ -98,8 +96,7 @@ unicode_block_new_object (UnicodeData *data)
                                     "end",
                                     data->end,
                                     "name",
-                                    data->name ? g_strdup (data->name)
-                                           : g_strdup (""),
+                                    data->name ? data->name : "",
                                    NULL);
     data->list = g_slist_append (data->list, block);
 }
@@ -285,7 +282,7 @@ ucd_parse_file (const gchar *filename,
                    filename, error ? error->message : "");
         goto failed_to_parse_ucd_names_list;
     }
-    head = end = content;
+    end = content;
     while (*end == '\n' && end - content < length) {
         end++;
         n++;
@@ -352,6 +349,7 @@ static void
 block_list_dump (IBusUnicodeBlock *block,
                  GString          *buff)
 {
+    gchar *line;
     g_return_if_fail (buff != NULL);
 
     g_string_append (buff, "    /* TRANSLATORS: You might refer the "         \
@@ -359,9 +357,10 @@ block_list_dump (IBusUnicodeBlock *block,
                            "                    the following command:\n"     \
                            "       msgmerge -C gucharmap.po ibus.po "         \
                            "ibus.pot */\n");
-    gchar *line = g_strdup_printf ("    N_(\"%s\"),\n",
-                                   ibus_unicode_block_get_name (block));
+    line = g_strdup_printf ("    N_(\"%s\"),\n",
+                            ibus_unicode_block_get_name (block));
     g_string_append (buff, line);
+    g_free (line);
 }
 
 static void
@@ -371,7 +370,7 @@ ucd_block_translatable_save (const gchar *filename,
     gchar *content = NULL;
     gsize length = 0;
     GError *error = NULL;
-    gchar *p;
+    gchar *p, *substr;
     GString *buff = NULL;
     int i;
     GSList *list = blocks_list;
@@ -392,25 +391,30 @@ ucd_block_translatable_save (const gchar *filename,
             break;
     }
     if (p != NULL) {
-        g_string_append (buff, g_strndup (content, p - content));
+        substr = g_strndup (content, p - content);
+        g_string_append (buff, substr);
+        g_free (substr);
         g_string_append_c (buff, '\n');
     }
     g_clear_pointer (&content, g_free);
 
-    g_string_append (buff, g_strdup ("\n"));
-    g_string_append (buff, g_strdup_printf ("/* This file is generated by %s. */", __FILE__));
-    g_string_append (buff, g_strdup ("\n"));
-    g_string_append (buff, g_strdup ("include <glib/gi18n.h>\n"));
-    g_string_append (buff, g_strdup ("\n"));
-    g_string_append (buff, g_strdup ("#ifndef __IBUS_UNICODE_GEN_H_\n"));
-    g_string_append (buff, g_strdup ("#define __IBUS_UNICODE_GEN_H_\n"));
-    g_string_append (buff, g_strdup ("const static char *unicode_blocks[] = {\n"));
+    g_string_append (buff, "\n");
+    substr = g_strdup_printf ("/* This file is generated by %s. */", __FILE__);
+    g_string_append (buff, substr);
+    g_free (substr);
+    g_string_append (buff, "\n");
+    g_string_append (buff, "include <glib/gi18n.h>\n");
+    g_string_append (buff, "\n");
+    g_string_append (buff, "#ifndef __IBUS_UNICODE_GEN_H_\n");
+    g_string_append (buff, "#define __IBUS_UNICODE_GEN_H_\n");
+    g_string_append (buff, "const static char *unicode_blocks[] = {\n");
     g_slist_foreach (list, (GFunc)block_list_dump, buff);
-    g_string_append (buff, g_strdup ("};\n"));
-    g_string_append (buff, g_strdup ("#endif\n"));
+    g_string_append (buff, "};\n");
+    g_string_append (buff, "#endif\n");
 
     if (!g_file_set_contents (filename, buff->str, -1, &error)) {
-        g_warning ("Failed to save emoji category file %s: %s", filename, error->message);
+        g_warning ("Failed to save emoji category file %s: %s",
+                   filename, error->message);
         g_error_free (error);
     }
 
diff --git a/util/IMdkit/FrameMgr.c b/util/IMdkit/FrameMgr.c
index 0e91b78e..80d019a0 100644
--- a/util/IMdkit/FrameMgr.c
+++ b/util/IMdkit/FrameMgr.c
@@ -851,7 +851,7 @@ static Bool _FrameMgrProcessPadding (FrameMgr fm, FmStatus* status)
             return True;
         }
         /*endif*/
-        next_type = FrameInstGetNextType (fm->fi, &info);
+        FrameInstGetNextType (fm->fi, &info);
         fm->idx += info.num;
         if ((fitr = _FrameIterCounterIncr (fm->iters, info.num)))
             _FrameMgrRemoveIter (fm, fitr);
@@ -1525,6 +1525,11 @@ static Iter IterInit (XimFrame frame, int count)
     register XimFrameType type;
 
     it = (Iter) Xmalloc (sizeof (IterRec));
+    if (!it) {
+        fprintf (stderr, "(XIM-IMdkit) WARNING: malloc failed in %s:%d.\n",
+                 __FILE__, __LINE__);
+        return NULL;
+    }
     it->template = frame;
     it->max_count = (count == NO_VALUE)  ?  0  :  count;
     it->allow_expansion = (count == NO_VALUE);
@@ -1669,8 +1674,15 @@ static Bool IterIsLoopEnd (Iter it, Bool *myself)
 
 static XimFrameType IterGetNextType (Iter it, XimFrameTypeInfo info)
 {
-    XimFrameType type = it->template->type;
+    XimFrameType type;
+
+    if (!it || !it->template) {
+        fprintf (stderr, "(XIM-IMdkit) WARNING: malloc failed in %s:%d.\n",
+                 __FILE__, __LINE__);
+	return (XimFrameType) NULL;
+    }
 
+    type = it->template->type;
     if (it->start_counter)
     {
         (*it->start_watch_proc) (it, it->client_data);
@@ -1766,7 +1778,15 @@ static XimFrameType IterGetNextType (Iter it, XimFrameTypeInfo info)
 
 static XimFrameType IterPeekNextType (Iter it, XimFrameTypeInfo info)
 {
-    XimFrameType type = it->template->type;
+    XimFrameType type;
+
+    if (!it->template) {
+        fprintf (stderr, "(XIM-IMdkit) WARNING: dereference pointer %s:%d.\n",
+                 __FILE__, __LINE__);
+        return (XimFrameType) NULL;
+    }
+
+    type = it->template->type;
 
     if (!it->allow_expansion  &&  it->cur_no >= it->max_count)
         return (EOL);
@@ -1866,6 +1886,9 @@ static FmStatus IterSetSize (Iter it, int num)
                     dr.num = NO_VALUE;
                     d = ChainMgrSetData (&it->cm, i, dr);
                 }
+                if (!d) {
+                    return FmNoMoreData;
+                }
                 /*endif*/
                 if (d->num == NO_VALUE)
                 {
@@ -2254,6 +2277,11 @@ static ExtraData ChainMgrSetData (ChainMgr cm,
                                   ExtraDataRec data)
 {
     Chain cur = (Chain) Xmalloc (sizeof (ChainRec));
+    if (!cur) {
+        fprintf (stderr, "(XIM-IMdkit) WARNING: malloc failed in %s:%d.\n",
+                 __FILE__, __LINE__);
+        return NULL;
+    }
 
     cur->frame_no = frame_no;
     cur->d = data;
diff --git a/util/IMdkit/i18nIc.c b/util/IMdkit/i18nIc.c
index 289837a6..14a3dc51 100644
--- a/util/IMdkit/i18nIc.c
+++ b/util/IMdkit/i18nIc.c
@@ -470,13 +470,16 @@ static XICAttribute *CreateNestedList (CARD16 attr_id,
     /*endfor*/
     
     nest_list = (XICAttribute *) malloc (sizeof (XICAttribute));
-    if (nest_list == NULL)
+    if (nest_list == NULL) {
+        XFree (values);
         return NULL;
+    }
     /*endif*/
     memset (nest_list, 0, sizeof (XICAttribute));
     nest_list->value = (void *) malloc (value_length);
     if (nest_list->value == NULL) {
         XFree (nest_list);
+        XFree (values);
         return NULL;
     }
     /*endif*/
@@ -539,7 +542,13 @@ static int GetICValue (Xi18n i18n_core,
                     attr_ret[n].attribute_id = xic_attr[j].attribute_id;
                     attr_ret[n].name_length = xic_attr[j].length;
                     attr_ret[n].name = malloc (xic_attr[j].length + 1);
-		    strcpy(attr_ret[n].name, xic_attr[j].name);
+                    if (!attr_ret[n].name) {
+                        fprintf (stderr,
+                                 "(XIM-IMdkit) WARNING: malloc failed in %s:%d.\n",
+                                 __FILE__, __LINE__);
+                    } else {
+                        strcpy(attr_ret[n].name, xic_attr[j].name);
+                    }
                     attr_ret[n].type = xic_attr[j].type;
                     n++;
                     i++;
@@ -560,7 +569,13 @@ static int GetICValue (Xi18n i18n_core,
                 attr_ret[n].attribute_id = xic_attr[j].attribute_id;
                 attr_ret[n].name_length = xic_attr[j].length;
                 attr_ret[n].name = malloc (xic_attr[j].length + 1);
-		strcpy(attr_ret[n].name, xic_attr[j].name);
+                if (!attr_ret[n].name) {
+                    fprintf (stderr,
+                             "(XIM-IMdkit) WARNING: malloc failed in %s:%d.\n",
+                             __FILE__, __LINE__);
+                } else {
+		    strcpy(attr_ret[n].name, xic_attr[j].name);
+                }
                 attr_ret[n].type = xic_attr[j].type;
                 n++;
                 break;
@@ -700,10 +715,15 @@ void _Xi18nChangeIC (XIMS ims,
         attrib_list[attrib_num].value_length = value_length;
         FrameMgrGetToken (fm, value);
         attrib_list[attrib_num].value = (void *) malloc (value_length + 1);
-        memmove (attrib_list[attrib_num].value, value, value_length);
-	((char *)attrib_list[attrib_num].value)[value_length] = '\0';
+        if (!attrib_list[attrib_num].value) {
+            fprintf (stderr, "(XIM-IMdkit) WARNING: malloc failed in %s:%d.\n",
+                     __FILE__, __LINE__);
+        } else {
+            memmove (attrib_list[attrib_num].value, value, value_length);
+            ((char *)attrib_list[attrib_num].value)[value_length] = '\0';
+            total_value_length += (value_length + 1);
+        }
         attrib_num++;
-        total_value_length += (value_length + 1);
     }
     /*endwhile*/
 
@@ -917,6 +937,12 @@ void _Xi18nGetIC (XIMS ims, IMProtocol *call_data, unsigned char *p)
     FrameMgrGetToken (fm, byte_length);
 
     attrID_list = (CARD16 *) malloc (sizeof (CARD16)*IC_SIZE);  /* bogus */
+    if (!attrID_list) {
+        fprintf (stderr, "(XIM-IMdkit) WARNING: malloc failed in %s:%d.\n",
+                 __FILE__, __LINE__);
+        FrameMgrFree (fm);
+        return;
+    }
     memset (attrID_list, 0, sizeof (CARD16)*IC_SIZE);
 
     number = 0;
@@ -1026,7 +1052,7 @@ void _Xi18nGetIC (XIMS ims, IMProtocol *call_data, unsigned char *p)
     {
         _Xi18nSendMessage (ims, connect_id, XIM_ERROR, 0, 0, 0);
         XFree (attrID_list);
-        FrameMgrFree (fm);
+        goto _Xi18nGetIC_finit;
         return;
     }
     /*endif*/
@@ -1097,6 +1123,7 @@ void _Xi18nGetIC (XIMS ims, IMProtocol *call_data, unsigned char *p)
     }
     /*endfor*/
     
+_Xi18nGetIC_finit:
     if (preedit_ret)
     {
         XFree (preedit_ret->value);
diff --git a/util/IMdkit/i18nMethod.c b/util/IMdkit/i18nMethod.c
index 36dd28ac..9c44e7fe 100644
--- a/util/IMdkit/i18nMethod.c
+++ b/util/IMdkit/i18nMethod.c
@@ -166,8 +166,14 @@ static Bool GetEncodings(Xi18n i18n_core, XIMEncodings **p_encoding)
     {
         (*p_encoding)->supported_encodings[i]
             = (char *) malloc (strlen (p->supported_encodings[i]) + 1);
-        strcpy ((*p_encoding)->supported_encodings[i],
-                p->supported_encodings[i]);
+        if (!((*p_encoding)->supported_encodings[i])) {
+            fprintf (stderr, "(XIM-IMdkit) WARNING: malloc failed in %s:%d.\n",
+                     __FILE__, __LINE__);
+
+        } else {
+            strcpy ((*p_encoding)->supported_encodings[i],
+                    p->supported_encodings[i]);
+        }
     }
     /*endif*/
     return True;
@@ -187,11 +193,17 @@ static char *ParseArgs (Xi18n i18n_core, int mode, XIMArg *args)
                 if (address->imvalue_mask & I18N_IM_LOCALE)
                     return IMLocale;
                 /*endif*/
+                /* address->im_locale will be released later and don't need
+                 * -Wanalyzer-malloc-leak flag in gcc 11.0.1.
+                 */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wanalyzer-malloc-leak"
                 address->im_locale = (char *) malloc (strlen (p->value) + 1);
                 if (!address->im_locale)
                     return IMLocale;
                 /*endif*/
                 strcpy (address->im_locale, p->value);
+#pragma GCC diagnostic pop
                 address->imvalue_mask |= I18N_IM_LOCALE;
             }
             else if (strcmp (p->name, IMServerTransport) == 0)
@@ -199,11 +211,14 @@ static char *ParseArgs (Xi18n i18n_core, int mode, XIMArg *args)
                 if (address->imvalue_mask & I18N_IM_ADDRESS)
                     return IMServerTransport;
                 /*endif*/
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wanalyzer-malloc-leak"
                 address->im_addr = (char *) malloc (strlen (p->value) + 1);
                 if (!address->im_addr)
                     return IMServerTransport;
                 /*endif*/
                 strcpy(address->im_addr, p->value);
+#pragma GCC diagnostic pop
                 address->imvalue_mask |= I18N_IM_ADDRESS;
             }
             else if (strcmp (p->name, IMServerName) == 0)
@@ -211,11 +226,14 @@ static char *ParseArgs (Xi18n i18n_core, int mode, XIMArg *args)
                 if (address->imvalue_mask & I18N_IM_NAME)
                     return IMServerName;
                 /*endif*/
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wanalyzer-malloc-leak"
                 address->im_name = (char *) malloc (strlen (p->value) + 1);
                 if (!address->im_name)
                     return IMServerName;
                 /*endif*/
                 strcpy (address->im_name, p->value);
+#pragma GCC diagnostic pop
                 address->imvalue_mask |= I18N_IM_NAME;
             }
             else if (strcmp (p->name, IMServerWindow) == 0)
@@ -698,7 +716,7 @@ static void ReturnSelectionNotify (Xi18n i18n_core, XSelectionRequestEvent *ev)
 {
     XEvent event;
     Display *dpy = i18n_core->address.dpy;
-    char buf[4096];
+    char buf[4096] = { '\0', };
 
     event.type = SelectionNotify;
     event.xselection.requestor = ev->requestor;
diff --git a/util/IMdkit/i18nOffsetCache.c b/util/IMdkit/i18nOffsetCache.c
index d5379051..e2fe8c6b 100644
--- a/util/IMdkit/i18nOffsetCache.c
+++ b/util/IMdkit/i18nOffsetCache.c
@@ -94,7 +94,7 @@ void _Xi18nSetPropertyOffset (Xi18nOffsetCache *offset_cache, Atom key,
     }
 
     assert (data != NULL);
-    if (offset_cache->size > 0) {
+    if (offset_cache->size > 0 && i < offset_cache->capacity) {
         data[i].key = key;
         data[i].offset = offset;
     }
diff --git a/util/IMdkit/i18nPtHdr.c b/util/IMdkit/i18nPtHdr.c
index eaeeee1c..8dc52714 100644
--- a/util/IMdkit/i18nPtHdr.c
+++ b/util/IMdkit/i18nPtHdr.c
@@ -181,8 +181,13 @@ static void OpenMessageProc(XIMS ims, IMProtocol *call_data, unsigned char *p)
     FrameMgrGetToken (fm, name);
     imopen->lang.length = str_length;
     imopen->lang.name = malloc (str_length + 1);
-    strncpy (imopen->lang.name, name, str_length);
-    imopen->lang.name[str_length] = (char) 0;
+    if (!imopen->lang.name) {
+        fprintf (stderr, "(XIM-IMdkit) WARNING: malloc failed in %s:%d.\n",
+                 __FILE__, __LINE__);
+    } else {
+        strncpy (imopen->lang.name, name, str_length);
+        imopen->lang.name[str_length] = (char) 0;
+    }
 
     FrameMgrFree (fm);
 
@@ -339,7 +344,7 @@ static XIMExt *MakeExtensionList (Xi18n i18n_core,
                                   int number,
                                   int *reply_number)
 {
-    XIMExt *ext_list;
+    XIMExt *ext_list = NULL;
     XIMExt *im_ext = (XIMExt *) i18n_core->address.extension;
     int im_ext_len = i18n_core->address.ext_num;
     int i;
@@ -358,7 +363,8 @@ static XIMExt *MakeExtensionList (Xi18n i18n_core,
         {
             for (j = 0;  j < (int) number;  j++)
             {
-                if (strcmp (lib_extension[j].name, im_ext[i].name) == 0)
+                if (lib_extension[j].name
+                    && strcmp (lib_extension[j].name, im_ext[i].name) == 0)
                 {
                     (*reply_number)++;
                     break;
@@ -389,7 +395,13 @@ static XIMExt *MakeExtensionList (Xi18n i18n_core,
             ext_list[i].minor_opcode = im_ext[i].minor_opcode;
             ext_list[i].length = im_ext[i].length;
             ext_list[i].name = malloc (im_ext[i].length + 1);
-            strcpy (ext_list[i].name, im_ext[i].name);
+            if (!ext_list[i].name) {
+                fprintf (stderr,
+                         "(XIM-IMdkit) WARNING: malloc failed in %s:%d.\n",
+                         __FILE__, __LINE__);
+            } else {
+                strcpy (ext_list[i].name, im_ext[i].name);
+            }
         }
         /*endfor*/
     }
@@ -401,13 +413,20 @@ static XIMExt *MakeExtensionList (Xi18n i18n_core,
         {
             for (j = 0;  j < (int)number;  j++)
             {
-                if (strcmp (lib_extension[j].name, im_ext[i].name) == 0)
+                if (lib_extension[j].name
+                    && strcmp (lib_extension[j].name, im_ext[i].name) == 0)
                 {
                     ext_list[n].major_opcode = im_ext[i].major_opcode;
                     ext_list[n].minor_opcode = im_ext[i].minor_opcode;
                     ext_list[n].length = im_ext[i].length;
                     ext_list[n].name = malloc (im_ext[i].length + 1);
-                    strcpy (ext_list[n].name, im_ext[i].name);
+                    if (!ext_list[n].name) {
+                        fprintf (stderr,
+                                 "(XIM-IMdkit) WARNING: malloc failed in %s:%d.\n",
+                                 __FILE__, __LINE__);
+                    } else {
+                        strcpy (ext_list[n].name, im_ext[i].name);
+                    }
                     n++;
                     break;
                 }
@@ -450,6 +469,11 @@ static void QueryExtensionMessageProc (XIMS ims,
     FrameMgrGetToken (fm, input_method_ID);
     FrameMgrGetToken (fm, byte_length);
     query_ext->extension = (XIMStr *) malloc (sizeof (XIMStr)*10);
+    if (!query_ext->extension) {
+        fprintf (stderr, "(XIM-IMdkit) WARNING: malloc failed in %s:%d.\n",
+                 __FILE__, __LINE__);
+        return;
+    }
     memset (query_ext->extension, 0, sizeof (XIMStr)*10);
     number = 0;
     while (FrameMgrIsIterLoopEnd (fm, &status) == False)
@@ -461,9 +485,20 @@ static void QueryExtensionMessageProc (XIMS ims,
         FrameMgrSetSize (fm, str_length);
         query_ext->extension[number].length = str_length;
         FrameMgrGetToken (fm, name);
+        /* I don't know why extension[number].name is detected as leak
+         * with -Wanalyzer-malloc-leak option in gcc 11.0.1.
+         */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wanalyzer-malloc-leak"
         query_ext->extension[number].name = malloc (str_length + 1);
-        strncpy (query_ext->extension[number].name, name, str_length);
-        query_ext->extension[number].name[str_length] = (char) 0;
+        if (!query_ext->extension[number].name) {
+            fprintf (stderr, "(XIM-IMdkit) WARNING: malloc failed in %s:%d.\n",
+                     __FILE__, __LINE__);
+        } else {
+            strncpy (query_ext->extension[number].name, name, str_length);
+            query_ext->extension[number].name[str_length] = (char) 0;
+        }
+#pragma GCC diagnostic pop
         number++;
     }
     /*endwhile*/
@@ -490,6 +525,8 @@ static void QueryExtensionMessageProc (XIMS ims,
         XFree (query_ext->extension[i].name);
     /*endfor*/
     XFree (query_ext->extension);
+    if (!ext_list)
+        return;
 
     fm = FrameMgrInit (query_extension_reply_fr,
                        NULL,
@@ -501,7 +538,10 @@ static void QueryExtensionMessageProc (XIMS ims,
     /* set length of BARRAY item in ext_fr */
     for (i = 0;  i < reply_number;  i++)
     {
-        str_size = strlen (ext_list[i].name);
+        if (ext_list[i].name)
+            str_size = strlen (ext_list[i].name);
+        else
+            str_size = 0;
         FrameMgrSetSize (fm, str_size);
     }
     /*endfor*/
@@ -700,7 +740,13 @@ static XIMAttribute *MakeIMAttributeList (Xi18n i18n_core,
                                     &value_length);
                 attrib_list[list_num].value_length = value_length;
                 attrib_list[list_num].value = (void *) malloc (value_length);
-                memset(attrib_list[list_num].value, 0, value_length);
+                if (attrib_list[list_num].value) {
+                    memset(attrib_list[list_num].value, 0, value_length);
+                } else {
+                    fprintf (stderr,
+                             "(XIM-IMdkit) WARNING: malloc failed in %s:%d.\n",
+                             __FILE__, __LINE__);
+                }
                 GetIMValueFromName (i18n_core,
                                     connect_id,
                                     attrib_list[list_num].value,
@@ -737,10 +783,10 @@ static void GetIMValuesMessageProc (XIMS ims,
     register int i;
     register int j;
     int number;
-    CARD16 *im_attrID_list;
-    char **name_list;
+    CARD16 *im_attrID_list = NULL;
+    char **name_list = NULL;
     CARD16 name_number;
-    XIMAttribute *im_attribute_list;
+    XIMAttribute *im_attribute_list = NULL;
     IMGetIMValuesStruct *getim = (IMGetIMValuesStruct *)&call_data->getim;
     CARD16 connect_id = call_data->any.connect_id;
     CARD16 input_method_ID;
@@ -753,8 +799,18 @@ static void GetIMValuesMessageProc (XIMS ims,
     FrameMgrGetToken (fm, input_method_ID);
     FrameMgrGetToken (fm, byte_length);
     im_attrID_list = (CARD16 *) malloc (sizeof (CARD16)*20);
+    if (!im_attrID_list) {
+        fprintf (stderr, "(XIM-IMdkit) WARNING: malloc failed in %s:%d.\n",
+                 __FILE__, __LINE__);
+        goto GetIMValuesMessageProc_finit;
+    }
     memset (im_attrID_list, 0, sizeof (CARD16)*20);
     name_list = (char **)malloc(sizeof(char *) * 20);
+    if (!name_list) {
+        fprintf (stderr, "(XIM-IMdkit) WARNING: malloc failed in %s:%d.\n",
+                 __FILE__, __LINE__);
+        goto GetIMValuesMessageProc_finit;
+    }
     memset(name_list, 0, sizeof(char *) * 20);
     number = 0;
     while (FrameMgrIsIterLoopEnd (fm, &status) == False)
@@ -792,8 +848,11 @@ static void GetIMValuesMessageProc (XIMS ims,
                                              im_attrID_list,
                                              &number,
                                              &list_len);
-    if (im_attrID_list)
-        XFree (im_attrID_list);
+    if (!im_attribute_list) {
+        fprintf (stderr, "(XIM-IMdkit) WARNING: malloc failed in %s:%d.\n",
+                 __FILE__, __LINE__);
+        goto GetIMValuesMessageProc_finit2;
+    }
     /*endif*/
 
     fm = FrameMgrInit (get_im_values_reply_fr,
@@ -815,11 +874,7 @@ static void GetIMValuesMessageProc (XIMS ims,
     if (!reply)
     {
         _Xi18nSendMessage (ims, connect_id, XIM_ERROR, 0, 0, 0);
-        FrameMgrFree (fm);
-        for (i = 0; i < iter_count; i++)
-            XFree(im_attribute_list[i].value);
-        XFree (im_attribute_list);
-        return;
+        goto GetIMValuesMessageProc_finit;
     }
     /*endif*/
     memset (reply, 0, total_size);
@@ -840,12 +895,18 @@ static void GetIMValuesMessageProc (XIMS ims,
                        0,
                        reply,
                        total_size);
-    FrameMgrFree (fm);
     XFree (reply);
 
-    for (i = 0; i < iter_count; i++)
-        XFree(im_attribute_list[i].value);
-    XFree (im_attribute_list);
+GetIMValuesMessageProc_finit:
+    FrameMgrFree (fm);
+GetIMValuesMessageProc_finit2:
+    if (im_attrID_list)
+        XFree (im_attrID_list);
+    if (im_attribute_list) {
+        for (i = 0; i < iter_count; i++)
+            XFree(im_attribute_list[i].value);
+        XFree (im_attribute_list);
+    }
 }
 
 static void CreateICMessageProc (XIMS ims,
@@ -1435,6 +1496,11 @@ static void EncodingNegotiatonMessageProc (XIMS ims,
     if (byte_length > 0)
     {
         enc_nego->encoding = (XIMStr *) malloc (sizeof (XIMStr)*10);
+        if (!enc_nego->encoding) {
+            fprintf (stderr, "(XIM-IMdkit) WARNING: malloc failed in %s:%d.\n",
+                     __FILE__, __LINE__);
+            goto EncodingNegotiatonMessageProc_finit;
+        }
         memset (enc_nego->encoding, 0, sizeof (XIMStr)*10);
         i = 0;
         while (FrameMgrIsIterLoopEnd (fm, &status) == False)
@@ -1446,9 +1512,21 @@ static void EncodingNegotiatonMessageProc (XIMS ims,
             FrameMgrSetSize (fm, str_length);
             enc_nego->encoding[i].length = str_length;
             FrameMgrGetToken (fm, name);
+            /* I don't know why encoding[i].name is detected as leak
+             * with -Wanalyzer-malloc-leak option in gcc 11.0.1.
+             */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wanalyzer-malloc-leak"
             enc_nego->encoding[i].name = malloc (str_length + 1);
+            if (!(enc_nego->encoding[i].name)) {
+                fprintf (stderr,
+                         "(XIM-IMdkit) WARNING: malloc failed in %s:%d.\n",
+                         __FILE__, __LINE__);
+                goto EncodingNegotiatonMessageProc_finit;
+            }
             strncpy (enc_nego->encoding[i].name, name, str_length);
             enc_nego->encoding[i].name[str_length] = '\0';
+#pragma GCC diagnostic pop
             i++;
         }
         /*endwhile*/
@@ -1460,20 +1538,37 @@ static void EncodingNegotiatonMessageProc (XIMS ims,
     if (byte_length > 0)
     {
         enc_nego->encodinginfo = (XIMStr *) malloc (sizeof (XIMStr)*10);
+        if (!enc_nego->encodinginfo) {
+            fprintf (stderr, "(XIM-IMdkit) WARNING: malloc failed in %s:%d.\n",
+                     __FILE__, __LINE__);
+            goto EncodingNegotiatonMessageProc_finit;
+        }
         memset (enc_nego->encodinginfo, 0, sizeof (XIMStr)*10);
         i = 0;
         while (FrameMgrIsIterLoopEnd (fm, &status) == False)
         {
             char *name;
             int str_length;
-            
+
             FrameMgrGetToken (fm, str_length);
             FrameMgrSetSize (fm, str_length);
             enc_nego->encodinginfo[i].length = str_length;
             FrameMgrGetToken (fm, name);
+            /* I don't know why encodinginfo[i].name is detected as leak
+             * with -Wanalyzer-malloc-leak option in gcc 11.0.1.
+             */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wanalyzer-malloc-leak"
             enc_nego->encodinginfo[i].name = malloc (str_length + 1);
+            if (!enc_nego->encodinginfo[i].name) {
+                fprintf (stderr,
+                         "(XIM-IMdkit) WARNING: malloc failed in %s:%d.\n",
+                         __FILE__, __LINE__);
+                goto EncodingNegotiatonMessageProc_finit;
+            }
             strncpy (enc_nego->encodinginfo[i].name, name, str_length);
             enc_nego->encodinginfo[i].name[str_length] = '\0';
+#pragma GCC diagnostic pop
             i++;
         }
         /*endwhile*/
@@ -1524,6 +1619,7 @@ static void EncodingNegotiatonMessageProc (XIMS ims,
                        total_size);
     XFree (reply);
 
+EncodingNegotiatonMessageProc_finit:
     /* free data for encoding list */
     if (enc_nego->encoding)
     {
diff --git a/util/IMdkit/i18nUtil.c b/util/IMdkit/i18nUtil.c
index 109dcdf9..c62154e7 100644
--- a/util/IMdkit/i18nUtil.c
+++ b/util/IMdkit/i18nUtil.c
@@ -46,6 +46,8 @@ _Xi18nNeedSwap (Xi18n i18n_core, CARD16 connect_id)
     CARD8 im_byteOrder = i18n_core->address.im_byteOrder;
     Xi18nClient *client = _Xi18nFindClient (i18n_core, connect_id);
 
+    if (!client)
+        return True;
     return (client->byte_order != im_byteOrder);
 }
 
@@ -67,6 +69,11 @@ Xi18nClient *_Xi18nNewClient(Xi18n i18n_core)
 	new_connect_id = ++connect_id;
     }
     /*endif*/
+    if (!client) {
+        fprintf (stderr, "(XIM-IMdkit) WARNING: malloc failed in %s:%d.\n",
+                 __FILE__, __LINE__);
+        return NULL;
+    }
     memset (client, 0, sizeof (Xi18nClient));
     client->connect_id = new_connect_id;
     client->pending = (XIMPending *) NULL;
@@ -113,7 +120,14 @@ void _Xi18nDeleteClient (Xi18n i18n_core, CARD16 connect_id)
                 ccp0->next = ccp->next;
             /*endif*/
             /* put it back to free list */
+            /* gcc 11.0.1 warns dereference of NULL with
+             * -Wanalyzer-null-dereference option
+             * but target should not be NULL.
+             */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wanalyzer-null-dereference"
             target->next = i18n_core->address.free_clients;
+#pragma GCC diagnostic pop
             i18n_core->address.free_clients = target;
             return;
         }
@@ -161,6 +175,12 @@ void _Xi18nSendMessage (XIMS ims,
 
     reply_length = header_size + length;
     reply = (unsigned char *) malloc (reply_length);
+    if (!reply) {
+        _Xi18nSendMessage (ims, connect_id, XIM_ERROR, 0, 0, 0);
+        XFree (reply_hdr);
+        FrameMgrFree (fm);
+        return;
+    }
     replyp = reply;
     memmove (reply, reply_hdr, header_size);
     replyp += header_size;
diff --git a/util/IMdkit/i18nX.c b/util/IMdkit/i18nX.c
index 5e5c15fa..152fc4e8 100644
--- a/util/IMdkit/i18nX.c
+++ b/util/IMdkit/i18nX.c
@@ -58,16 +58,21 @@ static XClient *NewXClient (Xi18n i18n_core, Window new_client)
     XClient *x_client;
 
     x_client = (XClient *) malloc (sizeof (XClient));
-    x_client->client_win = new_client;
-    x_client->accept_win = XCreateSimpleWindow (dpy,
-                                                DefaultRootWindow(dpy),
-                                                0,
-                                                0,
-                                                1,
-                                                1,
-                                                1,
-                                                0,
-                                                0);
+    if (!x_client) {
+        fprintf (stderr, "(XIM-IMdkit) WARNING: malloc failed in %s:%d.\n",
+                 __FILE__, __LINE__);
+    } else {
+        x_client->client_win = new_client;
+        x_client->accept_win = XCreateSimpleWindow (dpy,
+                                                    DefaultRootWindow(dpy),
+                                                    0,
+                                                    0,
+                                                    1,
+                                                    1,
+                                                    1,
+                                                    0,
+                                                    0);
+    }
     client->trans_rec = x_client;
     return ((XClient *) x_client);
 }
@@ -219,7 +224,7 @@ static void ReadXConnectMessage (XIMS ims, XClientMessageEvent *ev)
     }
     /*endif*/
     _XRegisterFilterByType (dpy,
-                            x_client->accept_win,
+                            x_client ? x_client->accept_win : 0,
                             ClientMessage,
                             ClientMessage,
                             WaitXIMProtocol,
@@ -229,7 +234,7 @@ static void ReadXConnectMessage (XIMS ims, XClientMessageEvent *ev)
     event.xclient.window = new_client;
     event.xclient.message_type = spec->connect_request;
     event.xclient.format = 32;
-    event.xclient.data.l[0] = x_client->accept_win;
+    event.xclient.data.l[0] = x_client ? x_client->accept_win : 0;
     event.xclient.data.l[1] = major_version;
     event.xclient.data.l[2] = minor_version;
     event.xclient.data.l[3] = XCM_DATA_LIMIT;