anthy-unicode/SOURCES/anthy-unicode-HEAD.patch

From c9f365df28640b1e5dd518f532e77e33fcb4451c Mon Sep 17 00:00:00 2001
From: fujiwarat <takao.fujiwara1@gmail.com>
Date: Tue, 13 Jul 2021 08:34:34 +0900
Subject: [PATCH] Code reviews

---
 anthy/corpus.h            |   1 +
 anthy/logger.h            |   1 +
 anthy/matrix.h            |   1 +
 calctrans/calctrans.c     |  57 +++++++++++---
 calctrans/corpus.c        |  44 +++++++++--
 calctrans/input_set.c     |  74 +++++++++++++++---
 calctrans/input_set.h     |   1 +
 configure.ac              |   2 +
 depgraph/mkdepgraph.c     |  68 ++++++++++++++--
 mkanthydic/mkfiledic.c    |  16 +++-
 mkworddic/calcfreq.c      |  26 +++++--
 mkworddic/mkdic.c         | 160 +++++++++++++++++++++++++++-----------
 mkworddic/mkdic.h         |   1 +
 mkworddic/mkudic.c        |  31 +++++++-
 mkworddic/writewords.c    |   3 +-
 src-diclib/conf.c         |  22 ++++--
 src-diclib/diclib_inner.h |   2 +-
 src-diclib/file_dic.c     |   2 +-
 src-diclib/filemap.c      |   8 +-
 src-diclib/logger.c       |  23 ++++++
 src-diclib/ruleparser.c   |  11 ++-
 src-diclib/xstr.c         |  84 +++++++++++++++++---
 src-main/context.c        | 102 ++++++++++++++++--------
 src-main/main.c           |  10 +--
 src-ordering/candswap.c   |  23 +++++-
 src-ordering/relation.c   |   6 +-
 src-splitter/compose.c    |  84 +++++++++++++++-----
 src-splitter/depgraph.c   |  15 +++-
 src-splitter/lattice.c    |  54 ++++++++++---
 src-splitter/metaword.c   |  22 ++++--
 src-splitter/segclass.c   |   4 +-
 src-splitter/splitter.c   |   6 ++
 src-util/agent.c          |  52 ++++++++++---
 src-util/convdb.c         |   8 +-
 src-util/dic-tool.c       |  86 +++++++++++++++++---
 src-util/egg.c            |   9 +++
 src-util/input.c          |  87 +++++++++++++++++----
 src-util/rkconv.c         |  46 ++++++++---
 src-worddic/dic_util.c    |  28 +++++--
 src-worddic/ext_ent.c     |  38 +++++++--
 src-worddic/feature_set.c |   7 ++
 src-worddic/matrix.c      |  75 +++++++++++++++---
 src-worddic/priv_dic.c    |  56 ++++++++-----
 src-worddic/record.c      |  30 +++++--
 src-worddic/textdict.c    |  31 +++++---
 src-worddic/texttrie.c    |  63 ++++++++++-----
 src-worddic/word_dic.c    |  20 ++++-
 src-worddic/word_lookup.c |   7 +-
 test/check.c              |  30 +++++--
 test/main.c               |  15 +++-
 test/test-matrix.c        |   7 ++
 51 files changed, 1314 insertions(+), 345 deletions(-)

diff --git a/anthy/corpus.h b/anthy/corpus.h
index 0a4a8e0..eedc41f 100644
--- a/anthy/corpus.h
+++ b/anthy/corpus.h
@@ -21,5 +21,6 @@ void corpus_build(struct corpus *c);
 void corpus_dump(struct corpus *c);
 void corpus_write_bucket(FILE *fp, struct corpus *c);
 void corpus_write_array(FILE *fp, struct corpus *c);
+void corpus_free(struct corpus *c);
 
 #endif
diff --git a/anthy/logger.h b/anthy/logger.h
index a80fb5f..7d0f08a 100644
--- a/anthy/logger.h
+++ b/anthy/logger.h
@@ -4,5 +4,6 @@
 
 void anthy_do_set_logger(void (*)(int , const char*), int lv);
 void anthy_log(int lv, const char *, ...);
+const char * anthy_strerror(int errnum);
 
 #endif
diff --git a/anthy/matrix.h b/anthy/matrix.h
index f424048..8245dca 100644
--- a/anthy/matrix.h
+++ b/anthy/matrix.h
@@ -22,5 +22,6 @@ void anthy_sparse_matrix_make_matrix(struct sparse_matrix *m);
 struct matrix_image *anthy_matrix_image_new(struct sparse_matrix *s);
 /* 行列イメージにアクセスするAPI(配列はnetwork byte order) */
 int anthy_matrix_image_peek(int *im, int row, int col);
+void anthy_sparse_matrix_free(struct sparse_matrix *m);
 
 #endif
diff --git a/calctrans/calctrans.c b/calctrans/calctrans.c
index 2855b7c..a5782c6 100644
--- a/calctrans/calctrans.c
+++ b/calctrans/calctrans.c
@@ -14,6 +14,7 @@
  *
  * Copyright (C) 2006 HANAOKA Toshiyuki
  * Copyright (C) 2006-2007 TABATA Yusuke
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  *
  */
 /*
@@ -31,17 +32,19 @@
   License along with this library; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
  */
+#include <assert.h>
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
 #include <math.h>
 
 #include <anthy/anthy.h>
-#include <anthy/xstr.h>
-#include <anthy/feature_set.h>
+#include <anthy/corpus.h>
 #include <anthy/diclib.h>
+#include <anthy/feature_set.h>
+#include <anthy/logger.h>
+#include <anthy/xstr.h>
 #include "input_set.h"
-#include <anthy/corpus.h>
 
 #define FEATURE_SET_SIZE NR_EM_FEATURES
 
@@ -155,7 +158,7 @@ static void
 parse_indep(struct input_info *m, struct sentence_info *sinfo,
 	    char *line, char *buf, int error_class)
 {
-  struct array features;
+  struct array features = { 0, };
   char *s;
   int weight = 1;
   /**/
@@ -341,6 +344,7 @@ dump_features(FILE *ofp, struct input_set *is)
   for (i = 0; i < nr; i++) {
     dump_line(ofp, lines[i]);
   }
+  free(lines);
 }
 
 static void
@@ -372,7 +376,8 @@ convert_line(FILE *ofp, char *buf)
 }
 
 static void
-convert_file(FILE *ifp)
+convert_file(FILE       *ifp,
+             const char *ifn)
 {
   char buf[1024];
   FILE *ofp = NULL;
@@ -400,6 +405,10 @@ convert_file(FILE *ifp)
 	write_nl(ofp, 0);
       }
     } else {
+      if (!ofp) {
+        anthy_log(0, "section could not found in %s\n", ifn);
+        continue;
+      }
       convert_line(ofp, buf);
     }
   }
@@ -420,7 +429,7 @@ convert_data(int nr_fn, char **fns)
       fprintf(stderr, "failed to open (%s)\n", fns[i]);
       continue;
     }
-    convert_file(ifp);
+    convert_file(ifp, fns[i]);
     fclose(ifp);
   }
 }
@@ -468,7 +477,10 @@ static void
 string_pool_sort(struct string_pool *sp)
 {
   int idx, h;
-  sp->array = malloc(sizeof(struct string_node *) * sp->nr);
+  if (!(sp->array = malloc(sizeof(struct string_node *) * sp->nr))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return;
+  }
   for (idx = 0, h = 0; h < STRING_HASH_SIZE; h++) {
     struct string_node *node;
     for (node = sp->hash[h].next_hash; node; node = node->next_hash) {
@@ -494,6 +506,7 @@ static unsigned int
 string_hash(const unsigned char *str)
 {
   unsigned int h = 0;
+  assert(str);
   while (*str) {
     h += *str;
     h *= 13;
@@ -526,10 +539,20 @@ static void
 flush_extract_stat(struct extract_stat *es, struct string_pool *sp)
 {
   int i;
+  assert(es);
+  if (es->nr > 0)
+    assert(es->info);
   for (i = 0; i < es->nr; i++) {
     if (es->info[i].valid) {
       struct string_node *node;
       node = find_string_node(sp, es->info[i].indep);
+      if (!node) {
+        anthy_log(0, "Failed malloc at %d/%d in %s:%d\n",
+                  i, es->nr, __FILE__, __LINE__);
+        free(es->info[i].indep);
+        es->info[i].indep = NULL;
+        continue;
+      }
       if (node->key == 0) {
 	xstr *xs = anthy_cstr_to_xstr(node->str, ANTHY_EUC_JP_ENCODING);
 	node->key = anthy_xstr_hash(xs);
@@ -585,6 +608,8 @@ static void
 fill_missed_word(struct extract_stat *es, char *buf)
 {
   char *c = get_indep_part(buf);
+  assert(es);
+  assert(es->info);
   if (!c) {
     return ;
   }
@@ -669,6 +694,10 @@ proc_corpus(int nr_fn, char **fns, FILE *ofp)
   fprintf(stderr, " %d sentences\n", m->nr_sentences);
   fprintf(stderr, " %d connections\n", m->nr_connections);
   fprintf(stderr, " %d segments\n", m->nr_connections - m->nr_sentences);
+  input_set_free(m->seg_is);
+  input_set_free(m->cand_is);
+  corpus_free(m->indep_corpus);
+  free(m);
 }
 
 int
@@ -682,7 +711,10 @@ main(int argc, char **argv)
   int extract = 0;
 
   ofp = NULL;
-  input_files = malloc(sizeof(char *) * argc);
+  if (!(input_files = malloc(sizeof(char *) * argc))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return 1;
+  }
   
   for (i = 1; i < argc; i++) {
     char *arg = argv[i];
@@ -700,15 +732,17 @@ main(int argc, char **argv)
       extract = 1;
     } else {
       input_files[nr_input] = arg;
-      nr_input ++;
+      nr_input++;
     }
   }
   if (extract) {
     printf(" -- extracting missed words\n");
-    if (!ofp) {
+    if (!ofp)
       ofp = stdout;
-    }
     extract_word(nr_input, input_files, ofp);
+    free(input_files);
+    if (ofp != stdout)
+      fclose(ofp);
     return 0;
   }
   if (ofp) {
@@ -720,6 +754,7 @@ main(int argc, char **argv)
     printf(" -- converting dictionary from text to binary form\n");
     convert_data(nr_input, input_files);
   }
+  free(input_files);
 
   return 0;
 }
diff --git a/calctrans/corpus.c b/calctrans/corpus.c
index 42f07ef..0b441e3 100644
--- a/calctrans/corpus.c
+++ b/calctrans/corpus.c
@@ -3,7 +3,7 @@
  * 現時点では例文をすべて入れているが、そのうちフィルターすることも考えられる
  *
  * Copyright (C) 2007 TABATA Yusuke
- *
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  */
 /*
   This library is free software; you can redistribute it and/or
@@ -20,11 +20,13 @@
   License along with this library; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
  */
+#include <assert.h>
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
 
 #include <anthy/corpus.h>
+#include <anthy/logger.h>
 
 #define MAX_NR_VAL 8
 #define BUCKET_SIZE 8192
@@ -95,6 +97,10 @@ struct corpus *
 corpus_new(void)
 {
   struct corpus *c = malloc(sizeof(*c));
+  if (!c) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return NULL;
+  }
   c->nr_node = 0;
   c->array_size = 0;
   c->array = NULL;
@@ -154,7 +160,11 @@ corpus_build_flatten(struct corpus *c)
   int i, j;
   int idx = 0;
   int nr_valid_elms = count_nr_valid_values(c);
-  c->elms = malloc(sizeof(struct element) * nr_valid_elms);
+  assert(c);
+  if (!(c->elms = calloc(nr_valid_elms, sizeof(struct element)))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return;
+  }
   for (i = 0; i < c->nr_node; i++) {
     struct node *nd = &c->array[i];
     if (nd->flags & ELM_INVALID) {
@@ -164,9 +174,8 @@ corpus_build_flatten(struct corpus *c)
       c->elms[idx].val = nd->val[j];
       c->elms[idx].next_idx = -1;
       c->elms[idx].flags = nd->flags;
-      if (j == 0) {
-	c->elms[idx].flags |= ELM_WORD_BORDER;
-      }
+      if (j == 0)
+        c->elms[idx].flags |= ELM_WORD_BORDER;
       c->elms[idx].idx = idx;
       idx++;
     }
@@ -177,7 +186,10 @@ static struct bucket *
 find_bucket(struct corpus *c, int val)
 {
   int i;
-  int h = val % c->nr_buckets;
+  int h;
+  assert(c);
+  assert(c->buckets);
+  h = val % c->nr_buckets;
   for (i = 0; i < MAX_COLLISION; i++) {
     struct bucket *bkt = &c->buckets[h];
     if (bkt->key == val) {
@@ -188,10 +200,10 @@ find_bucket(struct corpus *c, int val)
       return bkt;
     }
     /**/
-    h ++;
+    h++;
     h %= c->nr_buckets;
   }
-  c->bucket_collision ++;
+  c->bucket_collision++;
   return NULL;
 }
 
@@ -199,6 +211,11 @@ static void
 corpus_build_link(struct corpus *c)
 {
   int i;
+  assert(c);
+  if (!(c->elms)) {
+    anthy_log(0, "c->elms should not be null.\n");
+    return;
+  }
   for (i = 0; i < c->nr_values; i++) {
     struct element *elm = &c->elms[i];
     struct bucket *bkt = find_bucket(c, elm->val);
@@ -275,3 +292,14 @@ corpus_write_array(FILE *fp, struct corpus *c)
 	    c->elms[i].next_idx);
   }
 }
+
+void
+corpus_free (struct corpus *c)
+{
+  if (!c)
+    return;
+  free (c->array);
+  free (c->elms);
+  free (c->buckets);
+  free (c);
+}
diff --git a/calctrans/input_set.c b/calctrans/input_set.c
index 0a880b2..ccf108d 100644
--- a/calctrans/input_set.c
+++ b/calctrans/input_set.c
@@ -2,14 +2,18 @@
  *
  * Copyright (C) 2006 HANAOKA Toshiyuki
  * Copyright (C) 2006-2007 TABATA Yusuke
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  *
  * Special Thanks: Google Summer of Code Program 2006
  *
  */
+#include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <math.h>
+
+#include <anthy/logger.h>
 #include "input_set.h"
 
 #define HASH_SIZE 1024
@@ -75,11 +79,18 @@ add_line(struct input_set *is, int *features, int nr)
 {
   int i, h;
   struct input_line *il;
-  il = malloc(sizeof(struct input_line));
+  if (!(il = malloc(sizeof(struct input_line)))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return NULL;
+  }
   il->nr_features = nr;
-  il->features = malloc(sizeof(int) * nr);
-  for (i = 0; i < nr; i++) {
-    il->features[i] = features[i];
+  if (!(il->features = malloc(sizeof(int) * nr))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    il->nr_features = nr = 0;
+  } else {
+    for (i = 0; i < nr; i++) {
+      il->features[i] = features[i];
+    }
   }
   il->weight = 0;
   il->negative_weight = 0;
@@ -114,9 +125,10 @@ input_set_set_features(struct input_set *is, int *features,
 
   /**/
   il = find_same_line(is, features, nr);
-  if (!il) {
+  if (!il)
     il = add_line(is, features, nr);
-  }
+  if (!il)
+    return;
   /**/
   if (weight > 0) {
     il->weight += weight;
@@ -132,7 +144,10 @@ input_set_create(void)
 {
   int i;
   struct input_set *is;
-  is = malloc(sizeof(struct input_set));
+  if (!(is = malloc(sizeof(struct input_set)))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return NULL;
+  }
   is->lines = NULL;
   /**/
   for (i = 0; i < HASH_SIZE; i++) {
@@ -185,13 +200,46 @@ input_set_output_feature_freq(FILE *fp, struct input_set *is)
   }
 }
 
+static void
+input_line_free (struct input_line **il)
+{
+  assert (il);
+  if (!(*il))
+    return;
+  free ((*il)->features);
+  input_line_free (&((*il)->next_line));
+  free (*il);
+  *il = NULL;
+}
+
+void
+input_set_free (struct input_set *is)
+{
+  int i;
+  if (!is)
+      return;
+  input_line_free (&is->lines);
+  for (i = 0; i < HASH_SIZE; i++)
+    free (is->feature_freq->hash_head[i].next);
+  free (is->feature_freq->hash_head);
+  free (is->feature_freq);
+  free (is);
+}
+
 struct int_map *
 int_map_new(void)
 {
   int i;
   struct int_map *im = malloc(sizeof(struct int_map));
+  if (!im) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return NULL;
+  }
   im->nr = 0;
-  im->hash_head = malloc(sizeof(struct int_map_node) * HASH_SIZE);
+  if (!(im->hash_head = malloc(sizeof(struct int_map_node) * HASH_SIZE))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return im;
+  }
   for (i = 0; i < HASH_SIZE; i++) {
     im->hash_head[i].next = NULL;
   }
@@ -234,17 +282,20 @@ int_map_set(struct int_map *im, int idx, int val)
   int h;
   if (node) {
     node->val = val;
-    return ;
+    return;
   }
   /**/
-  node = malloc(sizeof(struct int_map_node));
+  if (!(node = malloc(sizeof(struct int_map_node)))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return;
+  }
   node->key = idx;
   node->val = val;
   h = node_index(idx);
   node->next = im->hash_head[h].next;
   im->hash_head[h].next = node;
   /**/
-  im->nr ++;
+  im->nr++;
 }
 
 void
@@ -253,6 +304,7 @@ int_map_flatten(struct int_map *im)
   int i;
   struct int_map_node *node;
   int max_n = 0;
+  assert(im->hash_head);
   /* 配列を準備する */
   im->array_size = im->nr * 2;
   im->array = malloc(sizeof(struct int_map_node *) * 
diff --git a/calctrans/input_set.h b/calctrans/input_set.h
index 45d5931..8d1f875 100644
--- a/calctrans/input_set.h
+++ b/calctrans/input_set.h
@@ -27,6 +27,7 @@ struct input_set *input_set_filter(struct input_set *is,
 void input_set_output_feature_freq(FILE *fp, struct input_set *is);
 /**/
 struct input_line *input_set_get_input_line(struct input_set *is);
+void input_set_free(struct input_set *is);
 
 
 struct int_map *int_map_new(void);
diff --git a/configure.ac b/configure.ac
index 7b011ec..270c3f2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -22,6 +22,8 @@ AC_PROG_CPP
 AM_PROG_LIBTOOL
 AM_PATH_LISPDIR
 
+AC_CHECK_FUNCS([strerror_r])
+
 AM_CONDITIONAL(ELISP, test x$lispdir != x)
 
 dnl without emacs. install-lispLISP does mkdir /anthy
diff --git a/depgraph/mkdepgraph.c b/depgraph/mkdepgraph.c
index 5a63d5b..b627283 100644
--- a/depgraph/mkdepgraph.c
+++ b/depgraph/mkdepgraph.c
@@ -1,6 +1,7 @@
 /*
  * Copyright (C) 2000-2007 TABATA Yusuke
  * Copyright (C) 2004-2006 YOSHIDA Yuichi
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  */
 /*
  * 付属語グラフをバイナリ化する
@@ -23,6 +24,7 @@
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
  */
 
+#include <assert.h>
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
@@ -54,7 +56,11 @@ static int nrRules;
 static int 
 get_node_id_by_name(const char *name)
 {
+  struct dep_node *tmp = NULL;
+  char **tmp2 = NULL;
   int i;
+  if (nrNodes > 0)
+    assert(gNodeNames);
   /* 登録済みのものから探す */
   for (i = 0; i < nrNodes; i++) {
     if (!strcmp(name,gNodeNames[i])) {
@@ -62,8 +68,24 @@ get_node_id_by_name(const char *name)
     }
   }
   /* なかったので作る */
-  gNodes = realloc(gNodes, sizeof(struct dep_node)*(nrNodes+1));
-  gNodeNames = realloc(gNodeNames, sizeof(char*)*(nrNodes+1));
+  if (!(tmp = realloc(gNodes, sizeof(struct dep_node)*(nrNodes+1)))) {
+    anthy_log(0, "Could not realloc gNodes.\n");
+    free(gNodes);
+    gNodes = NULL;
+    nrNodes = 0;
+    return 0;
+  }
+  gNodes = tmp;
+  if (!(tmp2 = realloc(gNodeNames, sizeof(char*)*(nrNodes+1)))) {
+    anthy_log(0, "Could not realloc gNodeNames.\n");
+    free(gNodes);
+    gNodes = NULL;
+    free(gNodeNames);
+    gNodeNames = NULL;
+    nrNodes = 0;
+    return 0;
+  }
+  gNodeNames = tmp2;
   gNodes[nrNodes].nr_branch = 0;
   gNodes[nrNodes].branch = 0;
   gNodeNames[nrNodes] = strdup(name);
@@ -78,6 +100,7 @@ find_branch(struct dep_node *node, xstr **strs, int nr_strs)
 {
   struct dep_branch *db;
   int i, j;
+  assert(node);
   /* 同じ遷移条件のブランチを探す */
   for (i = 0; i < node->nr_branch; i++) {
     db = &node->branch[i];
@@ -188,12 +211,15 @@ parse_dep(char **tokens, int nr)
   struct dep_branch *db;
   struct dep_node *dn;
   int nr_strs;
-  xstr **strs = alloca(sizeof(xstr*) * nr);
 
+  assert(gNodes);
+  xstr **strs = alloca(sizeof(xstr*) * nr);
   /* ノードとそのidを確保 */
   id = get_node_id_by_name(tokens[row]);
+  assert(id < nrNodes);
   dn = &gNodes[id];
-  row ++;
+  row++;
+  assert(dn);
 
   nr_strs = 0;
 
@@ -236,9 +262,14 @@ static void
 check_nodes(void)
 {
   int i;
+  if (nrNodes > 0) {
+    assert(gNodes);
+    assert(gNodeNames);
+  }
   for (i = 1; i < nrNodes; i++) {
     if (gNodes[i].nr_branch == 0) {
-      anthy_log(0, "node %s has no branch.\n", gNodeNames);
+      anthy_log(0, "node %s has no branch.\n",
+                gNodeNames ? gNodeNames[i] : "(null)");
     }
   }
 }
@@ -278,12 +309,28 @@ init_depword_tab(void)
 static void
 parse_indep(char **tokens, int nr)
 {
+  struct wordseq_rule *tmp = NULL;
   if (nr < 2) {
     printf("Syntex error in indepword defs"
 	   " :%d.\n", anthy_get_line_number());
     return ;
   }
-  gRules = realloc(gRules, sizeof(struct wordseq_rule)*(nrRules+1));
+  if (!(tmp = realloc(gRules, sizeof(struct wordseq_rule)*(nrRules+1)))) {
+    anthy_log(0, "Could not realloc gRules.\n");
+    /* CPPCHECK_WARNING and CLANG_WARNING are conflicted.
+     * CPPCHECK_WARNING reports: Common realloc mistake:
+     *     'gRules' nulled but not freed upon failure
+     * also CLANG_WARNING reports: Potential leak of memory ponted to by
+     *     'gRules'
+     * On the other hand,
+     * CLANG_WARNING reports: 'gRules' is freed twice.
+     */
+    free(gRules);
+    gRules = NULL;
+    nrRules = 0;
+    return;
+  }
+  gRules= tmp;
 
   /* 行の先頭には品詞の名前が入っている */
   gRules[nrRules].wt = anthy_init_wtype_by_name(tokens[0]);
@@ -295,7 +342,7 @@ parse_indep(char **tokens, int nr)
     printf("%d (%s)\n", nrRules, tokens[0]);
   }
 
-  nrRules ++;
+  nrRules++;
 }
 
 /** 自立語からの遷移表 */
@@ -405,6 +452,11 @@ write_file(const char* file_name)
   FILE* fp = fopen(file_name, "w");
   int* node_offset = malloc(sizeof(int) * nrNodes); /* gNodesのファイル上の位置 */
 
+  if (!fp) {
+    anthy_log(0, "Could not write-open %s.\n", file_name);
+    free(node_offset);
+    return;
+  }
   /* 各ルール */
   write_nl(fp, nrRules);
   for (i = 0; i < nrRules; ++i) {
@@ -414,6 +466,8 @@ write_file(const char* file_name)
 
   write_nl(fp, nrNodes);
 
+  if (nrNodes > 0)
+    assert(gNodes);
   for (i = 0; i < nrNodes; ++i) {
     write_node(fp, &gNodes[i]);
   }
diff --git a/mkanthydic/mkfiledic.c b/mkanthydic/mkfiledic.c
index 8611dae..f3e502b 100644
--- a/mkanthydic/mkfiledic.c
+++ b/mkanthydic/mkfiledic.c
@@ -18,7 +18,7 @@
  *
  * Copyright (C) 2005-2006 YOSHIDA Yuichi
  * Copyright (C) 2006-2007 TABATA Yusuke
- *
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  */
 /*
   This library is free software; you can redistribute it and/or
@@ -40,8 +40,9 @@
 #include <stdlib.h>
 #include <sys/stat.h>
 
-#include <anthy/xstr.h>
 #include <anthy/diclib.h>
+#include <anthy/logger.h>
+#include <anthy/xstr.h>
 
 #define SECTION_ALIGNMENT 64
 #define DIC_NAME "anthy.dic"
@@ -64,9 +65,10 @@ static int
 get_file_size(const char* fn)
 {
   struct stat st;
-  if (stat(fn, &st) < 0) {
+  if (!fn)
+    return -1;
+  if (stat(fn, &st) < 0)
     return -1;
-  }
   return (st.st_size + SECTION_ALIGNMENT - 1) & (-SECTION_ALIGNMENT);
 }
 
@@ -74,6 +76,10 @@ static char *
 get_file_name(const char *prefix, struct header_entry* entry)
 {
   char *fn = malloc(strlen(prefix) + strlen(entry->file_name) + 4);
+  if (!fn) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return NULL;
+  }
   sprintf(fn, "%s/%s", prefix, entry->file_name);
   return fn;
 }
@@ -157,6 +163,8 @@ write_contents(FILE* fp, const char *prefix,
     FILE* in_fp;
     char *fn = get_file_name(prefix, &entries[i]);
 
+    if (!fn)
+      break;
     in_fp = fopen(fn, "r");
     if (in_fp == NULL) {
       printf("failed to open %s\n", fn);
diff --git a/mkworddic/calcfreq.c b/mkworddic/calcfreq.c
index bb72b60..7743e16 100644
--- a/mkworddic/calcfreq.c
+++ b/mkworddic/calcfreq.c
@@ -1,5 +1,11 @@
-/* ñ<><C3B1><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>٤<EFBFBD><D9A4>׻<EFBFBD><D7BB><EFBFBD><EFBFBD><EFBFBD> */
+/* 単語の頻度を計算する
+ *
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
+ */
+
 #include <stdlib.h>
+
+#include <anthy/logger.h>
 #include "mkdic.h"
 
 static int
@@ -16,10 +22,11 @@ count_nr_words(struct yomi_entry_list *yl)
 static struct word_entry **
 make_word_array(struct yomi_entry_list *yl, int nr)
 {
-  struct word_entry **array = malloc(sizeof(struct word_entry *) *
-				    nr);
+  struct word_entry **array;
   int nth = 0;
   struct yomi_entry *ye;
+  if (!(array = malloc(sizeof(struct word_entry *) * nr)))
+    return NULL;
   for (ye = yl->head; ye; ye = ye->next) {
     int i;
     for (i = 0; i < ye->nr_entries; i++) {
@@ -30,7 +37,7 @@ make_word_array(struct yomi_entry_list *yl, int nr)
   return array;
 }
 
-/** qsort<72>Ѥ<EFBFBD><D1A4><EFBFBD><EFBFBD>Ӵؿ<D3B4> */
+/** qsort用の比較関数 */
 static int
 compare_word_entry_by_freq(const void *p1, const void *p2)
 {
@@ -47,7 +54,11 @@ set_freq(struct word_entry **array, int nr)
   percent = percent ? percent : 1;
   for (i = 0; i < nr; i++) {
     struct word_entry *we = array[i];
-    we->freq = 99 - (i / percent);
+    /* Effect よのなかほんとうにべんりになった in test/test.txt
+     * 便利 vs 弁理
+     * べんり #T05*300 便利 #T35*180 弁理 in alt-cannadic/gcanna.ctd
+     */
+    we->freq = (int)(99.0 - ((double)i / percent));
     if (we->freq < 1) {
       we->freq = 1;
     }
@@ -66,7 +77,10 @@ calc_freq(struct yomi_entry_list *yl)
   struct word_entry **we;
   /**/
   nr = count_nr_words(yl);
-  we = make_word_array(yl, nr);
+  if (!(we = make_word_array(yl, nr))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return;
+  }
   /**/
   qsort(we, nr,
 	sizeof(struct word_entry *),
diff --git a/mkworddic/mkdic.c b/mkworddic/mkdic.c
index eb042e4..b0f9f4c 100644
--- a/mkworddic/mkdic.c
+++ b/mkworddic/mkdic.c
@@ -6,6 +6,7 @@
  * Copyright (C) 2000-2007 TABATA Yusuke
  * Copyright (C) 2005 YOSHIDA Yuichi
  * Copyright (C) 2001-2002 TAKAI Kousuke
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  */
 /*
  * 辞書は読みをindexとし、品詞や変換後の単語(=entry)を検索
@@ -34,20 +35,22 @@
 
 #include <sys/types.h>
 #include <unistd.h>
+#include <assert.h>
+#include <errno.h>
+#include <ctype.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <errno.h>
-#include <ctype.h>
 
 #include <config.h>
 
 #include <anthy/anthy.h>
-#include <anthy/xstr.h>
-#include <anthy/wtype.h>
+#include <anthy/diclib.h>
+#include <anthy/logger.h>
 #include <anthy/ruleparser.h>
 #include <anthy/word_dic.h>
-#include <anthy/diclib.h>
+#include <anthy/wtype.h>
+#include <anthy/xstr.h>
 #include "mkdic.h"
 
 #define MAX_LINE_LEN 10240
@@ -104,31 +107,32 @@ static void
 open_output_files(void)
 {
   struct file_section *fs;
+  char *tmpdir = getenv("TMPDIR");
+  tmpdir = tmpdir ? strdup (tmpdir) : strdup ("/tmp");
   for (fs = file_array; fs->fpp; fs ++) {
-    char *tmpdir = getenv("TMPDIR");
+    char buf[256];
+    int fd = -1;
+    /* tmpfile()がTMPDIRを見ないため、TMPDIRを指定された場合mkstempを使う。
+     * tmpfile() creates files with predictable names, which is unsafe and
+     * is not recommended.
+     */
     fs->fn = NULL;
-    if (tmpdir) {
-      /* tmpfile()がTMPDIRを見ないため、TMPDIRを指定された場合mkstempを使う。*/
-      char buf[256];
-      int fd = -1;
-      snprintf(buf, sizeof(buf), "%s/mkanthydic.XXXXXX", tmpdir);
-      fd = mkstemp(buf);
-      if (fd == -1) {
-	*(fs->fpp) = NULL;
-      } else {
-	*(fs->fpp) = fdopen(fd, "w+");
-	fs->fn = strdup(buf);
-      }
+    snprintf(buf, sizeof(buf), "%s/mkanthydic.XXXXXX", tmpdir);
+    fd = mkstemp(buf);
+    if (fd == -1) {
+      *(fs->fpp) = NULL;
     } else {
-      *(fs->fpp) = tmpfile();
+      *(fs->fpp) = fdopen(fd, "w+");
+      fs->fn = strdup(buf);
     }
     /**/
     if (!(*(fs->fpp))) {
       fprintf (stderr, "%s: cannot open temporary file: %s\n",
-	       progname, strerror (errno));
+               progname, strerror (errno));
       exit (2);
     }
   }
+  free(tmpdir);
 }
 
 /* fflushする */
@@ -214,6 +218,7 @@ get_entry_from_line(char *buf)
 {
   char *sp;
   sp = strchr(buf, ' ');
+  assert(sp);
   while(*sp == ' ') {
     sp ++;
   }
@@ -275,7 +280,7 @@ push_back_word_entry(struct mkdic_stat *mds,
     s = strdup(word);
   }
   ye->entries[ye->nr_entries].word_utf8 = s;
-  ye->nr_entries ++;
+  ye->nr_entries++;
 }
 
 static int
@@ -432,8 +437,8 @@ static int
 check_same_word(struct yomi_entry *ye, int idx)
 {
   struct word_entry *base = &ye->entries[idx];
-  int i;
-  for (i = idx -1; i >= 0; i--) {
+  int i = idx - 1;
+  if (i >= 0) {
     struct word_entry *cur = &ye->entries[i];
     if (base->raw_freq != cur->raw_freq) {
       return 0;
@@ -535,7 +540,7 @@ find_yomi_entry(struct yomi_entry_list *yl, xstr *index, int create)
   ye->next = yl->head;
   yl->head = ye;
 
-  yl->nr_entries ++;
+  yl->nr_entries++;
 
   return ye;
 }
@@ -563,7 +568,10 @@ mk_yomi_hash(FILE *yomi_hash_out, struct yomi_entry_list *yl)
   unsigned char *hash_array;
   int i;
   struct yomi_entry *ye;
-  hash_array = (unsigned char *)malloc(YOMI_HASH_ARRAY_SIZE);
+  if (!(hash_array = (unsigned char *)malloc(YOMI_HASH_ARRAY_SIZE))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return;
+  }
   for (i = 0; i < YOMI_HASH_ARRAY_SIZE; i++) {
     hash_array[i] = 0;
   }
@@ -574,7 +582,7 @@ mk_yomi_hash(FILE *yomi_hash_out, struct yomi_entry_list *yl)
   fwrite(hash_array, YOMI_HASH_ARRAY_SIZE, 1, yomi_hash_out);
   printf("generated yomi hash bitmap (%d collisions/%d entries)\n",
 	 yomi_hash_collision, yl->nr_valid_entries);
-	 
+  free(hash_array);
 }
 
 static struct adjust_command *
@@ -590,22 +598,20 @@ parse_modify_freq_command (const char        *buf,
   wt = strtok (NULL, " ");
   word = strtok (NULL, " ");
   type_str = strtok (NULL, " ");
-  if (!yomi || !wt || !word || !type_str) {
+  if (!yomi || !wt || !word || !type_str)
     return NULL;
-  }
-  if (!strcmp (type_str, "up")) {
+  if (!strcmp (type_str, "up"))
     type = ADJUST_FREQ_UP;
-  }
-  if (!strcmp (type_str, "down")) {
+  if (!strcmp (type_str, "down"))
     type = ADJUST_FREQ_DOWN;
-  }
-  if (!strcmp (type_str, "kill")) {
+  if (!strcmp (type_str, "kill"))
     type = ADJUST_FREQ_KILL;
-  }
-  if (!type) {
+  if (!type)
+    return NULL;
+  if (!(cmd = malloc (sizeof (struct adjust_command)))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
     return NULL;
   }
-  cmd = malloc (sizeof (struct adjust_command));
   cmd->type = type;
   cmd->yomi = anthy_cstr_to_xstr (yomi, mds->input_encoding);
   cmd->wt = get_wt_name(wt);
@@ -691,8 +697,9 @@ apply_adjust_command(struct yomi_entry_list *yl,
 {
   struct adjust_command *cmd;
   for (cmd = ac_list->next; cmd; cmd = cmd->next) {
-    struct word_entry *we = find_word_entry(yl, cmd->yomi,
-					    cmd->wt, cmd->word);
+    struct word_entry *we;
+    assert(cmd);
+    we = find_word_entry(yl, cmd->yomi, cmd->wt, cmd->word);
     if (!we) {
       char *yomi = anthy_xstr_to_cstr(cmd->yomi, ANTHY_UTF8_ENCODING);
       printf("failed to find target of adjust command (%s, %s, %s)\n",
@@ -732,11 +739,14 @@ sort_word_dict(struct yomi_entry_list *yl)
   struct yomi_entry *ye;
   yl->nr_valid_entries = 0;
   /* 単語を持つ読みだけを yl->ye_arrayに詰め直す */
-  yl->ye_array = malloc(sizeof(struct yomi_entry *) * yl->nr_entries);
+  if (!(yl->ye_array = malloc(sizeof(struct yomi_entry *) * yl->nr_entries))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return;
+  }
   for (i = 0, ye = yl->head; i < yl->nr_entries; i++, ye = ye->next) {
     if (ye->nr_entries > 0) {
       yl->ye_array[yl->nr_valid_entries] = ye;
-      yl->nr_valid_entries ++;
+      yl->nr_valid_entries++;
     }
   }
   /**/
@@ -984,7 +994,10 @@ build_reverse_dict(struct mkdic_stat *mds)
   /* コピーする
    * (元の辞書中のポインタはreallocで動くのでコピーが必要)
    */
-  we_array = malloc(sizeof(struct word_entry )* n);
+  if (!(we_array = malloc(sizeof(struct word_entry )* n))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return;
+  }
   n = 0;
   for (ye = mds->yl.head; ye; ye = ye->next) {
     for (i = 0; i < ye->nr_entries; i++) {
@@ -1041,12 +1054,32 @@ static void
 set_exclude_wtypes(struct mkdic_stat *mds, int nr, char **tokens)
 {
   int i;
+  assert(nr > 0);
   mds->nr_excluded = nr - 1;
-  mds->excluded_wtypes = malloc(sizeof(char *) * (nr - 1));
+  if (nr == 1) {
+    anthy_log(0, "nr == 1 in %s:%d\n", __FILE__, __LINE__);
+    return;
+  }
+  if (!(mds->excluded_wtypes = malloc(sizeof(char *) * (nr - 1)))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    mds->nr_excluded = 0;
+    return;
+  }
   /**/
-  for (i = 1; i < nr; i++) {
+  mds->excluded_wtypes[0] = NULL;
+  for (i = 1; i < nr; i++)
     mds->excluded_wtypes[i - 1] = strdup(tokens[i]);
+}
+
+static void
+free_exclude_wtypes(struct mkdic_stat *mds)
+{
+  int i;
+  for (i = 0; i < mds->nr_excluded; i++) {
+    free (mds->excluded_wtypes[i]);
   }
+  free (mds->excluded_wtypes);
+  mds->excluded_wtypes = NULL;
 }
 
 static void
@@ -1098,14 +1131,18 @@ show_command(char **tokens, int nr)
 static int
 execute_batch(struct mkdic_stat *mds, const char *fn)
 {
-  int nr;
-  char **tokens;
+  int nr = 0;
+  char **tokens = NULL;
   if (anthy_open_file(fn)) {
     printf("mkanthydic: failed to open %s\n", fn);
     return 1;
   }
   while (!anthy_read_line(&tokens, &nr)) {
-    char *cmd = tokens[0];
+    char *cmd;
+    if (!nr)
+      break;
+    assert(nr > 0);
+    cmd = tokens[0];
     show_command(tokens, nr);
     if (!strcmp(cmd, "read") && nr == 2) {
       read_dict_file(mds, tokens[1]);
@@ -1160,6 +1197,29 @@ init_mds(struct mkdic_stat *mds)
   mds->excluded_wtypes = NULL;
 }
 
+static void
+free_yomi_entry_list(struct yomi_entry_list *yl)
+{
+  struct yomi_entry *ye, *ye_prev;
+  int i;
+
+  free (yl->ye_array);
+  yl->ye_array = NULL;
+  for (i = 0, ye = yl->head; ye && (i < yl->nr_entries); i++) {
+    free (ye->index_xstr->str);
+    free (ye->index_xstr);
+    ye->index_xstr = NULL;
+    free (ye->index_str);
+    ye->index_str = NULL;
+    free (ye->entries);
+    ye->entries = NULL;
+    ye->hash_next = NULL;
+    ye_prev = ye;
+    ye = ye->next;
+    free (ye_prev);
+  }
+}
+
 /* libanthyの使用する部分だけを初期化する */
 static void
 init_libs(void)
@@ -1180,6 +1240,7 @@ main(int argc, char **argv)
   int i;
   char *script_fn = NULL;
   int help_mode = 0;
+  int retval;
 
   anthy_init_wtypes();
   init_libs();
@@ -1200,5 +1261,10 @@ main(int argc, char **argv)
     print_usage();
   }
 
-  return execute_batch(&mds, script_fn);
+  retval = execute_batch(&mds, script_fn);
+  free_yomi_entry_list(&mds.yl);
+  free_exclude_wtypes(&mds);
+  free_uc_dict(mds.ud);
+  mds.ud = NULL;
+  return retval;
 }
diff --git a/mkworddic/mkdic.h b/mkworddic/mkdic.h
index 3885c4f..ec09ec0 100644
--- a/mkworddic/mkdic.h
+++ b/mkworddic/mkdic.h
@@ -85,6 +85,7 @@ const char *get_wt_name(const char *name);
  * 用例辞書を作る */
 struct uc_dict *create_uc_dict(void);
 void read_uc_file(struct uc_dict *ud, const char *fn);
+void free_uc_dict(struct uc_dict *dict);
 void make_ucdict(FILE *out, struct uc_dict *uc);
 /**/
 
diff --git a/mkworddic/mkudic.c b/mkworddic/mkudic.c
index 1bdf6ee..12d0a78 100644
--- a/mkworddic/mkudic.c
+++ b/mkworddic/mkudic.c
@@ -2,11 +2,13 @@
  * 用例辞書を作る
  *
  * Copyright (C) 2003-2005 TABATA Yusuke
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  */
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
 
+#include <anthy/logger.h>
 #include <anthy/matrix.h>
 #include "mkdic.h"
 
@@ -54,7 +56,10 @@ commit_uc(struct uc_dict *dict, int x, int y)
   if (x < 0 || y < 0) {
     return ;
   }
-  uc = malloc(sizeof(struct use_case));
+  if (!(uc = malloc(sizeof(struct use_case)))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return;
+  }
   uc->id[0] = x;
   uc->id[1] = y;
   /**/
@@ -68,6 +73,10 @@ struct uc_dict *
 create_uc_dict(void)
 {
   struct uc_dict *dict = malloc(sizeof(struct uc_dict));
+  if (!dict) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return NULL;
+  }
 
   dict->uc_head.next = NULL;
   dict->nr_ucs = 0;
@@ -120,6 +129,22 @@ read_uc_file(struct uc_dict *dict, const char *fn)
     }
     off ++;
   }
+  fclose(uc_file);
+}
+
+void
+free_uc_dict(struct uc_dict *dict)
+{
+  struct use_case *uc, *prev_uc;
+
+  if (!dict)
+    return;
+  for (uc = dict->uc_head.next; uc; ) {
+    prev_uc = uc;
+    uc = uc->next;
+    free (prev_uc);
+  }
+  free (dict);
 }
 
 /* 用例辞書をファイルに書き出す */
@@ -148,5 +173,7 @@ make_ucdict(FILE *uc_out, struct uc_dict *dict)
   } else {
     printf("udic: no use examples.\n");
   }
-
+  anthy_sparse_matrix_free(sm);
+  free(mi->image);
+  free(mi);
 }
diff --git a/mkworddic/writewords.c b/mkworddic/writewords.c
index d8eead7..e6e767c 100644
--- a/mkworddic/writewords.c
+++ b/mkworddic/writewords.c
@@ -7,6 +7,7 @@
  * output_word_dict()が呼び出される
  *
  * Copyright (C) 2000-2006 TABATA Yusuke
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  */
 /*
   This library is free software; you can redistribute it and/or
@@ -126,7 +127,7 @@ static int
 common_len(xstr *s1, xstr *s2)
 {
   int m,i;
-  if (!s1 || !s2) {
+  if ((!s1) || (!s2)) {
     return 0;
   }
   if (s1->len < s2->len) {
diff --git a/src-diclib/conf.c b/src-diclib/conf.c
index 810bf80..271052d 100644
--- a/src-diclib/conf.c
+++ b/src-diclib/conf.c
@@ -4,6 +4,7 @@
  * 変数の関係に注意
  *
  * Copyright (C) 2000-2007 TABATA Yusuke
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  */
 /*
   This library is free software; you can redistribute it and/or
@@ -20,6 +21,7 @@
   License along with this library; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
  */
+#include <assert.h>
 #include <unistd.h>
 #include <pwd.h>
 #include <time.h>
@@ -89,7 +91,13 @@ get_subst(const char *s)
       strchr(s, '}')) {
     struct val_ent *val;
     char *var = strdup(&s[2]);
-    char *k = strchr(var, '}');
+    char *k;
+    if (!var) {
+      anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+      return NULL;
+    }
+    k = strchr(var, '}');
+    assert(k);
     *k = 0;
     val = find_val_ent(var);
     free(var);
@@ -125,7 +133,10 @@ expand_string(const char *s)
   struct expand_buf eb;
   char *res;
   eb.size = 256;
-  eb.buf = malloc(eb.size);
+  if (!(eb.buf = malloc(eb.size))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return NULL;
+  }
   eb.cur = eb.buf;
   eb.len = 0;
 
@@ -139,13 +150,14 @@ expand_string(const char *s)
       eb.cur += len;
       eb.len += len;
       s = strchr(s, '}');
-      s ++;
+      assert(s);
+      s++;
     } else {
       *eb.cur = *s;
       /**/
-      eb.cur ++;
+      eb.cur++;
       s++;
-      eb.len ++;
+      eb.len++;
     }
     /**/
     ensure_buffer(&eb, 256);
diff --git a/src-diclib/diclib_inner.h b/src-diclib/diclib_inner.h
index 9da45ab..1b0f277 100644
--- a/src-diclib/diclib_inner.h
+++ b/src-diclib/diclib_inner.h
@@ -17,7 +17,7 @@ typedef enum
 /* file_dic.h */
 int anthy_init_file_dic(void);
 void anthy_quit_file_dic(void);
-
+int anthy_file_test(const char   *filename, AnthyFileTest test);
 
 /* xchar.c */
 void anthy_init_xchar_tab(void);
diff --git a/src-diclib/file_dic.c b/src-diclib/file_dic.c
index 2869648..5602ff0 100644
--- a/src-diclib/file_dic.c
+++ b/src-diclib/file_dic.c
@@ -121,7 +121,7 @@ anthy_path_skip_root (const char *file_name)
 /* anthy_file_test:
  * Copy from g_file_test()
  */
-static int
+int
 anthy_file_test (const char   *filename,
                  AnthyFileTest test)
 {
diff --git a/src-diclib/filemap.c b/src-diclib/filemap.c
index c810719..1e228eb 100644
--- a/src-diclib/filemap.c
+++ b/src-diclib/filemap.c
@@ -4,7 +4,7 @@
  * *将来的には一つのファイルを複数の目的にmapすることも考慮
  *
  * Copyright (C) 2005 TABATA Yusuke
- *
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  */
 /*
   This library is free software; you can redistribute it and/or
@@ -89,7 +89,11 @@ anthy_mmap(const char *fn, int wr)
   }
 
   /* mmapに成功したので情報を返す */
-  m = malloc(sizeof(struct filemapping));
+  if (!(m = malloc(sizeof(struct filemapping)))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    munmap(ptr, st.st_size);
+    return NULL;
+  }
   m->size = st.st_size;
   m->ptr = ptr;
   m->wr = wr;
diff --git a/src-diclib/logger.c b/src-diclib/logger.c
index 6e6d402..233a488 100644
--- a/src-diclib/logger.c
+++ b/src-diclib/logger.c
@@ -1,9 +1,11 @@
 /*
  * ログの出力
  * $Id: logger.c,v 1.8 2002/05/14 13:24:47 yusuke Exp $
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  */
 #include <stdio.h>
 #include <stdarg.h>
+#include <string.h>
 
 #include <anthy/anthy.h>
 #include <anthy/logger.h>
@@ -46,3 +48,24 @@ anthy_set_logger(anthy_logger lg, int level)
 {
   anthy_do_set_logger(lg, level);
 }
+
+const char *
+anthy_strerror (int errnum)
+{
+  const char *msg;
+  static char buf[1024];
+
+#if defined(HAVE_STRERROR_R)
+#  if defined(__GLIBC__) && !((_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600) && ! _GNU_SOURCE)
+      msg = strerror_r (errnum, buf, sizeof (buf));
+#  else
+      strerror_r (errnum, buf, sizeof (buf));
+      msg = buf;
+#  endif /* HAVE_STRERROR_R */
+#else
+      strncpy (buf, strerror (errnum), sizeof (buf));
+      buf[sizeof (buf) - 1] = '\0';
+      msg = buf;
+#endif
+  return msg;
+}
diff --git a/src-diclib/ruleparser.c b/src-diclib/ruleparser.c
index d83deac..7a40e37 100644
--- a/src-diclib/ruleparser.c
+++ b/src-diclib/ruleparser.c
@@ -3,6 +3,7 @@
  * 汎用のファイル読み込みモジュール
  *
  * Copyright (C) 2000-2006 TABATA Yusuke
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  *
  */
 /*
@@ -21,6 +22,7 @@
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
  */
 #include <ctype.h>
+#include <limits.h>
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
@@ -137,9 +139,11 @@ get_token_in(struct line_stat *ls)
   }
   /* トークンが始まるまで空白を読み飛ばす */
   do {
+    /* tainted cc should be sanitized */
+    cc = 0;
     esc = mygetc(&cc);
-  } while (cc > 0 && myisblank(cc) && esc == 0);
-  if (cc == -1) {
+  } while (cc != EOF && cc > 0 && cc < INT_MAX && myisblank(cc) && esc == 0);
+  if (cc == EOF) {
     return NULL;
   }
   if (cc == '\n'){
@@ -209,7 +213,8 @@ proc_include(void)
     anthy_log(0, "Syntax error in include directive.\n");
     return ;
   }
-  if (g_ps.cur_fpp > MAX_INCLUDE_DEPTH - 1) {
+  /* (i + 1) should < MAX_INCLUDE_DEPTH for g_ps.fp_stack[i + 1] */
+  if (g_ps.cur_fpp >= MAX_INCLUDE_DEPTH - 1) {
     anthy_log(0, "Too deep include.\n");
     return ;
   }
diff --git a/src-diclib/xstr.c b/src-diclib/xstr.c
index 018a63d..21f3e04 100644
--- a/src-diclib/xstr.c
+++ b/src-diclib/xstr.c
@@ -11,7 +11,7 @@
  *  cstrはCの普通のEUC文字列
  *
  * Copyright (C) 2000-2007 TABATA Yusuke
- *
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  */
 /*
   This library is free software; you can redistribute it and/or
@@ -28,6 +28,7 @@
   License along with this library; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
  */
+#include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -35,6 +36,7 @@
 #include "config.h"
 /* for ANTHY_*_ENCODING */
 #include <anthy/anthy.h>
+#include <anthy/logger.h>
 
 #include <anthy/xstr.h>
 #include <anthy/xchar.h>
@@ -217,7 +219,8 @@ anthy_xstr_to_cstr(xstr *s, int encoding)
       l++;
     }
   }
-  p = (char *)malloc(l + 1);
+  if (!(p = (char *)malloc(l + 1)))
+    return NULL;
   p[l] = 0;
   j = 0;
   for (i =  0; i < s->len; i++) {
@@ -240,9 +243,13 @@ anthy_xstr_dup(xstr *s)
 {
   int i;
   xstr *x = (xstr *)malloc(sizeof(xstr));
+  if (!x)
+    return NULL;
   x->len = s->len;
   if (s->len) {
-    x->str = malloc(sizeof(xchar)*s->len);
+    assert(s->str);
+    if (!(x->str = malloc(sizeof(xchar)*s->len)))
+      return x;
   }else{
     x->str = NULL;
   }
@@ -258,8 +265,10 @@ anthy_xstr_dup_str(xstr *s)
   xchar *c;
   int i;
   if (s->len) {
-    c = malloc(sizeof(xchar)*s->len);
-  }else{
+    assert(s->str);
+    if (!(c = malloc(sizeof(xchar)*s->len)))
+      return NULL;
+  } else {
     c = 0;
   }
   for (i = 0; i < s->len; i++) {
@@ -443,8 +452,11 @@ xstr *
 anthy_xstrcat(xstr *s, xstr *a)
 {
   int i, l;
+  xchar *xch;
   if (!s) {
     s = malloc(sizeof(xstr));
+    if (!s)
+      return NULL;
     s->str = NULL;
     s->len = 0;
   }
@@ -457,7 +469,16 @@ anthy_xstrcat(xstr *s, xstr *a)
     return s;
   }
 
+  xch = s->str;
   s->str = realloc(s->str, sizeof(xchar)*l);
+  if (!s->str) {
+    anthy_log(0, "Failed realloc in %s:%d\n", __FILE__, __LINE__);
+    s->str = xch;
+    s->len = l - a->len;
+    return s;
+  }
+  if (a->len)
+    assert(a->str);
   for (i = 0; i < a->len; i ++) {
     s->str[s->len+i] = a->str[i];
   }
@@ -480,14 +501,14 @@ long long
 anthy_xstrtoll(xstr *x)
 {
   xchar c;
-  int i;
+  int i, t = XCT_NONE;
   long long n = 0;/* 数 */
-  if (!x->len || x->len > 16) {
+  if (!x->len || x->len > 16)
     return -1;
-  }
-  if ((!anthy_get_xstr_type(x)) & (XCT_NUM | XCT_WIDENUM)) {
+  for (i = 0; i < x->len; i++)
+    t |= anthy_get_xchar_type(x->str[i]);
+  if (!(t & (XCT_NUM | XCT_WIDENUM)))
     return -1;
-  }
   for (i = 0; i < x->len; i++) {
     c = x->str[i];
     n *= 10;
@@ -503,7 +524,15 @@ anthy_xstr_wide_num_to_num(xstr* src_xs)
 {
   int i;
   xstr *dst_xs;
-  dst_xs = anthy_xstr_dup(src_xs);
+  if (!(dst_xs = anthy_xstr_dup(src_xs))) {
+    anthy_log(0, "Failed anthy_xstr_dup() in %s:%d\n", __FILE__, __LINE__);
+    return NULL;
+  }
+  assert(src_xs);
+  if (src_xs->len) {
+    assert(src_xs->str);
+    assert(dst_xs->str);
+  }
   for (i = 0; i < src_xs->len; ++i) {
     dst_xs->str[i] = anthy_xchar_wide_num_to_num(src_xs->str[i]);
   }
@@ -518,6 +547,15 @@ anthy_xstr_hira_to_kata(xstr *src_xs)
   xstr *dst_xs;
   int i, j;
   dst_xs = anthy_xstr_dup(src_xs);
+  if (!dst_xs) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return NULL;
+  }
+  if (dst_xs->len && !dst_xs->str) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    dst_xs->len = 0;
+    return dst_xs;
+  }
 
   for (i = 0 ,j = 0; i < dst_xs->len; i++, j++) {
     /* 「う゛」のチェック */
@@ -553,8 +591,20 @@ anthy_xstr_hira_to_half_kata(xstr *src_xs)
     }
   }
   xs = malloc(sizeof(xstr));
+  if (!xs) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return NULL;
+  }
   xs->len = len;
   xs->str = malloc(sizeof(xchar) * len);
+  if (len) {
+    assert(src_xs->str);
+    if (!xs->str) {
+      anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+      xs->len = 0;
+      return xs;
+    }
+  }
   j = 0;
   for (i = 0; i < src_xs->len; i++) {
     const struct half_kana_table *tab = anthy_find_half_kana(src_xs->str[i]);
@@ -583,6 +633,18 @@ anthy_conv_half_wide(xstr *xs)
     }
   }
   res = anthy_xstr_dup(xs);
+  if (!res) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return NULL;
+  }
+  if (xs->len > 0) {
+    assert(xs->str);
+    if (!res->str) {
+      anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+      res->len = 0;
+      return res;
+    }
+  }
   for (i = 0; i < xs->len; i++) {
     res->str[i] = anthy_lookup_half_wide(xs->str[i]);
   }
diff --git a/src-main/context.c b/src-main/context.c
index 1b211db..20dde71 100644
--- a/src-main/context.c
+++ b/src-main/context.c
@@ -8,6 +8,7 @@
  *
  * Funded by IPA未踏ソフトウェア創造事業 2001 10/29
  * Copyright (C) 2000-2007 TABATA Yusuke
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  *
  * $Id: context.c,v 1.26 2002/11/17 14:45:47 yusuke Exp $
  */
@@ -26,16 +27,20 @@
   License along with this library; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
  */
+#include <assert.h>
+#include <fcntl.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <unistd.h>
 
+#include <errno.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 
 #include <anthy/anthy.h>
 #include <anthy/alloc.h>
+#include <anthy/logger.h>
 #include <anthy/record.h>
 #include <anthy/ordering.h>
 #include <anthy/splitter.h>
@@ -81,10 +86,15 @@ release_segment(struct seg_ent *s)
       anthy_release_cand_ent(s->cands[i]);
     }
     free (s->cands);
-  }
-  if (s->mw_array) {
-    free(s->mw_array);
-  }
+    s->cands = NULL;
+  }
+  free(s->mw_array);
+  s->mw_array = NULL;
+  s->best_mw = NULL;
+  s->str.str = NULL;
+  s->str.len = 0;
+  s->next = NULL;
+  s->prev = NULL;
   free(s);
 
 }
@@ -96,12 +106,13 @@ pop_back_seg_ent(struct anthy_context *c)
   struct seg_ent *s;
   s = c->seg_list.list_head.prev;
   if (s == &c->seg_list.list_head) {
-    return ;
+    return;
   }
   s->prev->next = s->next;
   s->next->prev = s->prev;
+  c->seg_list.list_head.prev = s->next->prev;
   release_segment(s);
-  c->seg_list.nr_segments --;
+  c->seg_list.nr_segments--;
 }
 
 
@@ -174,7 +185,10 @@ create_segment(struct anthy_context *ac, int from, int len,
 	       struct meta_word* best_mw)
 {
   struct seg_ent* s;
-  s = (struct seg_ent *)malloc(sizeof(struct seg_ent));
+  if (!(s = (struct seg_ent *)malloc(sizeof(struct seg_ent)))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return NULL;
+  }
   s->str.str = &ac->str.str[from];
   s->str.len = len;
   s->from = from;
@@ -191,6 +205,7 @@ create_segment(struct anthy_context *ac, int from, int len,
 static void
 push_back_segment(struct anthy_context *ac, struct seg_ent *se)
 {
+  assert(se);
   se->next = &ac->seg_list.list_head;
   se->prev = ac->seg_list.list_head.prev;
   ac->seg_list.list_head.prev->next = se;
@@ -236,7 +251,10 @@ anthy_do_create_context(int encoding)
     return NULL;
   }
 
-  ac = (struct anthy_context *)anthy_smalloc(context_ator);
+  if (!(ac = (struct anthy_context *)anthy_smalloc(context_ator))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return NULL;
+  }
   ac->str.str = NULL;
   ac->str.len = 0;
   ac->seg_list.nr_segments = 0;
@@ -383,15 +401,20 @@ anthy_do_resize_segment(struct anthy_context *ac,
 
   /* resizeが可能か検査する */
   if (nth >= ac->seg_list.nr_segments) {
-    return ;
+    return;
   }
   index = get_nth_segment_index(ac, nth);
   len = get_nth_segment_len(ac, nth);
   if (index + len + resize > ac->str.len) {
-    return ;
+    return;
   }
   if (len + resize < 1) {
-    return ;
+    return;
+  }
+  if (index < 0) {
+    anthy_log(0, "Wrong segment index for %dth %s:%d\n",
+              nth, __FILE__, __LINE__);
+    return;
   }
 
   /* nth以降のseg_entを解放する */
@@ -454,7 +477,7 @@ anthy_do_set_prediction_str(struct anthy_context *ac, xstr* xs)
     }
   }
 
-  prediction->str.str = (xchar*)malloc(sizeof(xchar*)*(xs->len+1));
+  prediction->str.str = (xchar*)malloc(sizeof(xchar) * (xs->len + 1));
   anthy_xstrcpy(&prediction->str, xs);
   prediction->str.str[xs->len]=0;
 
@@ -497,30 +520,31 @@ get_change_state(struct anthy_context *ac)
 }
 
 static void
-write_history(FILE *fp, struct anthy_context *ac)
+write_history(int                   fd,
+              struct anthy_context *ac)
 {
   int i;
   /* 読み */
-  fprintf(fp, "|");
+  dprintf(fd, "|");
   for (i = 0; i < ac->seg_list.nr_segments; i++) {
     struct seg_ent *s = anthy_get_nth_segment(&ac->seg_list, i);
     char *c = anthy_xstr_to_cstr(&s->str, ANTHY_EUC_JP_ENCODING);
-    fprintf(fp, "%s|", c);
+    dprintf(fd, "%s|", c);
     free(c);
   }
-  fprintf(fp, " |");
+  dprintf(fd, " |");
   /* 結果 */
   for (i = 0; i < ac->seg_list.nr_segments; i++) {
     struct seg_ent *s = anthy_get_nth_segment(&ac->seg_list, i);
     char *c;
     /**/
     if (s->committed < 0) {
-      fprintf(fp, "?|");
+      dprintf(fd, "?|");
       continue ;
     }
     c = anthy_xstr_to_cstr(&s->cands[s->committed]->str,
 			   ANTHY_EUC_JP_ENCODING);
-    fprintf(fp, "%s|", c);
+    dprintf(fd, "%s|", c);
     free(c);
   }
 }
@@ -528,28 +552,37 @@ write_history(FILE *fp, struct anthy_context *ac)
 void
 anthy_save_history(const char *fn, struct anthy_context *ac)
 {
-  FILE *fp;
+  int fd;
   struct stat st;
   if (!fn) {
-    return ;
+    return;
   }
-  fp = fopen(fn, "a");
-  if (!fp) {
-    return ;
+  /* TOCTOU: Use fchmod() and fstat(). chmod() after stat() can cause a
+   * time-of-check, time-of-use race condition.
+   */
+  errno = 0;
+  fd = open(fn, O_RDWR | O_CREAT | O_APPEND, S_IRUSR | S_IWUSR);
+  if (fd == -1) {
+    anthy_log(0, "Failed to open %s: %s\n", fn, anthy_strerror(errno));
+    return;
   }
-  if (stat(fn, &st) ||
+  if (fstat(fd, &st) ||
       st.st_size > HISTORY_FILE_LIMIT) {
-    fclose(fp);
-    return ;
+    close(fd);
+    return;
   }
   /**/
-  fprintf(fp, "anthy-%s ", anthy_get_version_string());
-  fprintf(fp, "%s ", get_change_state(ac));
-  write_history(fp, ac);
-  fprintf(fp, "\n");
-  fclose(fp);
+  dprintf(fd, "anthy-%s ", anthy_get_version_string());
+  dprintf(fd, "%s ", get_change_state(ac));
+  write_history(fd, ac);
+  dprintf(fd, "\n");
   /**/
-  chmod(fn, S_IREAD | S_IWRITE);
+  errno = 0;
+  if (fchmod(fd, S_IREAD | S_IWRITE)) {
+    anthy_log(0, "Failed chmod in %s:%d: %s\n",
+              __FILE__, __LINE__, anthy_strerror(errno));
+  }
+  close(fd);
 }
 
 /** 候補を表示する */
@@ -674,7 +707,10 @@ anthy_do_set_personality(const char *id)
   if (!id || strchr(id, '/')) {
     return -1;
   }
-  current_personality = strdup(id);
+  if (!(current_personality = strdup(id))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return -1;
+  }
   anthy_dic_set_personality(current_personality);
   return 0;
 }
diff --git a/src-main/main.c b/src-main/main.c
index f492737..ae5c805 100644
--- a/src-main/main.c
+++ b/src-main/main.c
@@ -12,7 +12,7 @@
  * Copyright (C) 2004-2006 YOSHIDA Yuichi
  * Copyright (C) 2000-2007 KMC(Kyoto University Micro Computer Club)
  * Copyright (C) 2001-2002 TAKAI Kosuke, Nobuoka Takahiro
- *
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  */
 /*
   This library is free software; you can redistribute it and/or
@@ -202,7 +202,7 @@ int
 anthy_set_string(struct anthy_context *ac, const char *s)
 {
   xstr *xs;
-  int retval;
+  int retval = 0;
 
   if (!ac) {
     return -1;
@@ -227,7 +227,7 @@ anthy_set_string(struct anthy_context *ac, const char *s)
   /**/
   if (!need_reconvert(ac, xs)) {
     /* 普通に変換する */
-    retval = anthy_do_context_set_str(ac, xs, 0);
+    retval |= anthy_do_context_set_str(ac, xs, 0);
   } else {
     /* 漢字やカタカナが混じっていたら再変換してみる */
     struct anthy_conv_stat stat;
@@ -235,7 +235,7 @@ anthy_set_string(struct anthy_context *ac, const char *s)
     int i;
     xstr* hira_xs;
     /* 与えられた文字列に変換をかける */
-    retval = anthy_do_context_set_str(ac, xs, 1);
+    retval |= anthy_do_context_set_str(ac, xs, 1);
 
     /* 各文節の第一候補を取得して平仮名列を得る */
     anthy_get_stat(ac, &stat);
@@ -246,7 +246,7 @@ anthy_set_string(struct anthy_context *ac, const char *s)
     }
     /* 改めて変換を行なう */
     anthy_release_segment_list(ac);
-    retval = anthy_do_context_set_str(ac, hira_xs, 0);
+    retval |= anthy_do_context_set_str(ac, hira_xs, 0);
     anthy_free_xstr(hira_xs);
   }
 
diff --git a/src-ordering/candswap.c b/src-ordering/candswap.c
index d2b2767..a512b24 100644
--- a/src-ordering/candswap.c
+++ b/src-ordering/candswap.c
@@ -8,9 +8,13 @@
  *  自立語部:「田端」->「田畑」
  *    の二つのエントリを追加する
  *
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
+ *
  */
 #include <stdlib.h>
+#include <stdio.h>
 
+#include <anthy/logger.h>
 #include <anthy/record.h>
 #include <anthy/segment.h>
 /* for OCHAIRE_SCORE */
@@ -106,10 +110,22 @@ prepare_swap_candidate(xstr *target)
   }
 
   if (!anthy_xstrcmp(target, n)) {
+    int i;
+    char buff[256];
     /* 第一候補 -> xs -> n で n = 第一候補のループ */
-    anthy_select_row(target, 0);
+    if (anthy_select_row(target, 0)) {
+      for (i = 0; i < 3 && i < target->len; i++)
+        sprintf (buff + i * 6, "%04X, ", target->str[i]);
+      anthy_log(0, "No current selection or Could not find %s in %s:%d.\n",
+                buff, __FILE__, __LINE__);
+    }
     anthy_release_row();
-    anthy_select_row(xs, 0);
+    if (anthy_select_row(xs, 0)) {
+      for (i = 0; i < 3 && i < xs->len; i++)
+        sprintf (buff + i * 6, "%04X, ", xs->str[i]);
+      anthy_log(0, "No current selection or Could not find %s in %s:%d.\n",
+                buff, __FILE__, __LINE__);
+    }
     anthy_release_row();
     /* 第一候補 -> xs を消して、交換の必要は無し */
     return NULL;
@@ -157,7 +173,8 @@ proc_swap_candidate_indep(struct seg_ent *se)
   }
 
   /**/
-  anthy_select_section("INDEPPAIR", 1);
+  if (anthy_select_section("INDEPPAIR", 1))
+    anthy_log(0, "Failed to save INDEPPAIR in %s:%d.\n", __FILE__, __LINE__);
   xs = prepare_swap_candidate(&key);
   free(key.str);
   if (!xs) {
diff --git a/src-ordering/relation.c b/src-ordering/relation.c
index 3db183a..651f48e 100644
--- a/src-ordering/relation.c
+++ b/src-ordering/relation.c
@@ -2,9 +2,9 @@
  * 文節の関係を処理する
  * Copyright (C) 2006 Higashiyama Masahiko (thanks google summer of code program)
  * Copyright (C) 2002-2007 TABATA Yusuke
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  *
  * anthy_reorder_candidates_by_relation()
- *
  */
 /*
   This library is free software; you can redistribute it and/or
@@ -427,10 +427,8 @@ anthy_relation_init(void)
 {
   corpus_info.corpus_array = anthy_file_dic_get_section("corpus_array");
   corpus_info.corpus_bucket = anthy_file_dic_get_section("corpus_bucket");
-  if (!corpus_info.corpus_array ||
-      !corpus_info.corpus_array) {
+  if (!corpus_info.corpus_array || !corpus_info.corpus_bucket)
     return ;
-  }
   corpus_info.array_size = ntohl(((int *)corpus_info.corpus_array)[1]);
   corpus_info.bucket_size = ntohl(((int *)corpus_info.corpus_bucket)[1]);
   corpus_info.array = &(((int *)corpus_info.corpus_array)[16]);
diff --git a/src-splitter/compose.c b/src-splitter/compose.c
index 998a157..70b841a 100644
--- a/src-splitter/compose.c
+++ b/src-splitter/compose.c
@@ -13,6 +13,7 @@
  * Copyright (C) 2000-2005 TABATA Yusuke
  * Copyright (C) 2004-2005 YOSHIDA Yuichi
  * Copyright (C) 2002 UGAWA Tomoharu
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  *
  * $Id: compose.c,v 1.25 2005/08/19 04:20:25 oxy Exp $
  */
@@ -31,11 +32,13 @@
   License along with this library; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
  */
+#include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include <anthy/dic.h>
+#include <anthy/logger.h>
 #include <anthy/splitter.h>
 #include <anthy/segment.h>
 #include "wordborder.h"
@@ -45,7 +48,10 @@ static struct cand_ent *
 alloc_cand_ent(void)
 {
   struct cand_ent *ce;
-  ce = (struct cand_ent *)malloc(sizeof(struct cand_ent));
+  if (!(ce = (struct cand_ent *)malloc(sizeof(struct cand_ent)))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return NULL;
+  }
   ce->nr_words = 0;
   ce->elm = NULL;
   ce->mw = NULL;
@@ -62,18 +68,22 @@ dup_candidate(struct cand_ent *ce)
 {
   struct cand_ent *ce_new;
   int i;
-  ce_new = alloc_cand_ent();
+  if (!(ce_new = alloc_cand_ent()))
+    return NULL;
   ce_new->nr_words = ce->nr_words;
   ce_new->str.len = ce->str.len;
   ce_new->str.str = anthy_xstr_dup_str(&ce->str);
-  ce_new->elm = malloc(sizeof(struct cand_elm)*ce->nr_words);
+  if (!(ce_new->elm = malloc(sizeof(struct cand_elm)*ce->nr_words))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    ce_new->nr_words = 0;
+  }
   ce_new->flag = ce->flag;
   ce_new->core_elm_index = ce->core_elm_index;
   ce_new->mw = ce->mw;
   ce_new->score = ce->score;
   ce_new->dep_word_hash = ce->dep_word_hash;
 
-  for (i = 0 ; i < ce->nr_words ; i++) {
+  for (i = 0 ; i < ce_new->nr_words ; i++) {
     ce_new->elm[i] = ce->elm[i];
   }
   return ce_new;
@@ -84,9 +94,16 @@ static void
 push_back_candidate(struct seg_ent *seg, struct cand_ent *ce)
 {
   /* seg_entに候補ceを追加 */
+  struct cand_ent **cands = seg->cands;
   seg->nr_cands++;
   seg->cands = (struct cand_ent **)
     realloc(seg->cands, sizeof(struct cand_ent *) * seg->nr_cands);
+  if (!seg->cands) {
+    anthy_log(0, "Failed realloc in %s:%d\n", __FILE__, __LINE__);
+    seg->cands = cands;
+    seg->nr_cands--;
+    return;
+  }
   seg->cands[seg->nr_cands - 1] = ce;
   /**/
   if (anthy_splitter_debug_flags() & SPLITTER_DEBUG_CAND) {
@@ -143,6 +160,9 @@ enum_candidates(struct seg_ent *seg,
     }
     return 1;
   }
+  /* ce->nr_words == ce->mw->nr_parts from make_candidate_from_simple_metaword()
+   */
+  assert(n < ce->nr_words);
 
   p = anthy_get_nr_dic_ents(ce->elm[n].se, &ce->elm[n].str);
 
@@ -160,7 +180,11 @@ enum_candidates(struct seg_ent *seg,
 
       yomi.len = ce->elm[n].str.len;
       yomi.str = &seg->str.str[from];
-      cand = dup_candidate(ce);
+      if (!(cand = dup_candidate(ce))) {
+        anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+        return 0;
+      }
+      assert(n < cand->nr_words);
       anthy_get_nth_dic_ent_str(cand->elm[n].se,
 				&yomi, i, &word);
       cand->elm[n].nth = i;
@@ -183,7 +207,11 @@ enum_candidates(struct seg_ent *seg,
     xstr xs;
     xs.len = ce->elm[n].str.len;
     xs.str = &seg->str.str[from];
-    cand = dup_candidate(ce);
+    if (!(cand = dup_candidate(ce))) {
+      anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+      return 0;
+    }
+    assert(n < cand->nr_words);
     cand->elm[n].nth = -1;
     cand->elm[n].id = -1;
     anthy_xstrcat(&cand->str, &xs);
@@ -286,19 +314,21 @@ make_cand_elem_from_word_list(struct seg_ent *se,
       /* 長さの無いpartは無視する */
       continue;
     }
-    if (i == PART_CORE) {
-      ce->core_elm_index = i + index;
-    }
     core_xs.str = &se->str.str[from];
     core_xs.len = part->len;
     if (i == PART_DEPWORD) {
       ce->dep_word_hash = anthy_dep_word_hash(&core_xs);
     }
-    ce->elm[i + index].se = anthy_get_seq_ent_from_xstr(&core_xs, is_reverse);
-    ce->elm[i + index].str.str = core_xs.str;
-    ce->elm[i + index].str.len = core_xs.len;
-    ce->elm[i + index].wt = part->wt;
-    ce->elm[i + index].ratio = RATIO_BASE * wl->len;
+    if ((i + index) < ce->nr_words) {
+      if (i == PART_CORE)
+        ce->core_elm_index = i + index;
+      assert(ce->elm);
+      ce->elm[i + index].se = anthy_get_seq_ent_from_xstr(&core_xs, is_reverse);
+      ce->elm[i + index].str.str = core_xs.str;
+      ce->elm[i + index].str.len = core_xs.len;
+      ce->elm[i + index].wt = part->wt;
+      ce->elm[i + index].ratio = RATIO_BASE * wl->len;
+    }
     from += part->len;
   }
 }
@@ -321,7 +351,10 @@ make_candidate_from_simple_metaword(struct seg_ent *se,
   ce->nr_words = mw->nr_parts;
   ce->str.str = NULL;
   ce->str.len = 0;
-  ce->elm = calloc(sizeof(struct cand_elm),ce->nr_words);
+  if (!(ce->elm = calloc(sizeof(struct cand_elm),ce->nr_words))) {
+    anthy_log(0, "Failed calloc in %s:%d\n", __FILE__, __LINE__);
+    ce->nr_words = 0;
+  }
   ce->mw = mw;
   ce->score = 0;
 
@@ -352,12 +385,19 @@ make_candidate_from_combined_metaword(struct seg_ent *se,
   struct cand_ent *ce;
 
   /* 複数(1も含む)の単語で構成される文節に単語を割当てていく */
-  ce = alloc_cand_ent();
+  if (!(ce = alloc_cand_ent())) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return;
+  }
   ce->nr_words = mw->nr_parts;
   ce->score = 0;
   ce->str.str = NULL;
   ce->str.len = 0;
-  ce->elm = calloc(sizeof(struct cand_elm),ce->nr_words);
+  if (!(ce->elm = calloc(sizeof(struct cand_elm),ce->nr_words))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    free(ce);
+    return;
+  }
   ce->mw = top_mw;
 
   /* 接頭辞, 自立語部, 接尾辞, 付属語 */
@@ -409,7 +449,10 @@ proc_splitter_info(struct seg_ent *se,
     /* 連文節の葉 */
     {
       struct cand_ent *ce;
-      ce = alloc_cand_ent();
+      if (!(ce = alloc_cand_ent())) {
+        anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+        break;
+      }
       ce->str.str = anthy_xstr_dup_str(&mw->cand_hint);
       ce->str.len = mw->cand_hint.len;
       ce->flag = CEF_COMPOUND;
@@ -425,7 +468,10 @@ proc_splitter_info(struct seg_ent *se,
     /* metawordを持たない候補文字列が
        直接に指定された */
       struct cand_ent *ce;
-      ce = alloc_cand_ent();
+      if (!(ce = alloc_cand_ent())) {
+        anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+        break;
+      }
       ce->str.str = anthy_xstr_dup_str(&mw->cand_hint);
       ce->str.len = mw->cand_hint.len;
       ce->mw = top_mw;
diff --git a/src-splitter/depgraph.c b/src-splitter/depgraph.c
index 118791a..c9ab36c 100644
--- a/src-splitter/depgraph.c
+++ b/src-splitter/depgraph.c
@@ -18,7 +18,9 @@
  *
  * Copyright (C) 2000-2007 TABATA Yusuke
  * Copyright (C) 2006 YOSHIDA Yuichi
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  */
+#include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -247,10 +249,14 @@ static void
 read_node(struct dep_dic* ddic, struct dep_node* node, int* offset)
 {
   int i;
+  assert(offset);
   node->nr_branch = anthy_dic_ntohl(*(int*)&ddic->file_ptr[*offset]);
   *offset += sizeof(int);
 
-  node->branch = malloc(sizeof(struct dep_branch) * node->nr_branch);
+  if (!(node->branch = malloc(sizeof(struct dep_branch) * node->nr_branch))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    node->nr_branch = 0;
+  }
   for (i = 0; i < node->nr_branch; ++i) {
     read_branch(ddic, &node->branch[i], offset);
   }
@@ -277,7 +283,10 @@ read_file(void)
   offset += sizeof(int);
 
   /* 各ノードを読み込む */
-  ddic.nodes = malloc(sizeof(struct dep_node) * ddic.nrNodes);
+  if (!(ddic.nodes = malloc(sizeof(struct dep_node) * ddic.nrNodes))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    ddic.nrNodes = 0;
+  }
   for (i = 0; i < ddic.nrNodes; ++i) {
     read_node(&ddic, &ddic.nodes[i], &offset);
   }
@@ -313,6 +322,8 @@ anthy_quit_depword_tab(void)
   for (i = 0; i < ddic.nrNodes; i++) {
     struct dep_node* node = &ddic.nodes[i];
     free(node->branch);
+    node->branch = NULL;
   }
   free(ddic.nodes);
+  ddic.nodes = NULL;
 }
diff --git a/src-splitter/lattice.c b/src-splitter/lattice.c
index cc6c8f2..72cd599 100644
--- a/src-splitter/lattice.c
+++ b/src-splitter/lattice.c
@@ -9,7 +9,7 @@
  * Copyright (C) 2006-2007 TABATA Yusuke
  * Copyright (C) 2004-2006 YOSHIDA Yuichi
  * Copyright (C) 2006 HANAOKA Toshiyuki
- *
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  */
 /*
   This library is free software; you can redistribute it and/or
@@ -37,17 +37,19 @@
  * (2) グラフを後ろ(右)からたどって最適なパスを求める
  *
  */
+#include <assert.h>
+#include <math.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <math.h>
 
 #include <anthy/alloc.h>
-#include <anthy/xstr.h>
+#include <anthy/diclib.h>
+#include <anthy/feature_set.h>
+#include <anthy/logger.h>
 #include <anthy/segclass.h>
 #include <anthy/splitter.h>
-#include <anthy/feature_set.h>
-#include <anthy/diclib.h>
+#include <anthy/xstr.h>
 #include "wordborder.h"
 
 static float anthy_normal_length = 20.0; /* 文節の期待される長さ */
@@ -82,6 +84,7 @@ struct lattice_info {
   struct splitter_context *sc;
   /* ノードのアロケータ */
   allocator node_allocator;
+  int lattice_node_len;
 };
 
 /*
@@ -210,6 +213,8 @@ get_transition_probability(struct lattice_node *node)
   probability = calc_probability(node->seg_class, &features);
   anthy_feature_list_free(&features);
 
+  if (!(node->mw))
+      return probability;
   /* 文節の形に対する評価 */
   probability *= get_form_bias(node->mw);
   return probability;
@@ -223,9 +228,15 @@ alloc_lattice_info(struct splitter_context *sc, int size)
   info->sc = sc;
   info->lattice_node_list = (struct node_list_head*)
     malloc((size + 1) * sizeof(struct node_list_head));
-  for (i = 0; i < size + 1; i++) {
-    info->lattice_node_list[i].head = NULL;
-    info->lattice_node_list[i].nr_nodes = 0;
+  if (!(info->lattice_node_list)) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    info->lattice_node_len = 0;
+  } else {
+    info->lattice_node_len = size + 1;
+    for (i = 0; i < size + 1; i++) {
+      info->lattice_node_list[i].head = NULL;
+      info->lattice_node_list[i].nr_nodes = 0;
+    }
   }
   info->node_allocator = anthy_create_allocator(sizeof(struct lattice_node),
 						NULL);
@@ -235,6 +246,7 @@ alloc_lattice_info(struct splitter_context *sc, int size)
 static void
 calc_node_parameters(struct lattice_node *node)
 {
+  assert(node);
   /* 対応するmetawordが無い場合は文頭と判断する */
   node->seg_class = node->mw ? node->mw->seg_class : SEG_HEAD;
 
@@ -345,6 +357,8 @@ cmp_node(struct lattice_node *lhs, struct lattice_node *rhs)
   }
 
   /* 最後に遷移確率を見る */
+  assert(lhs);
+  assert(rhs);
   if (lhs->adjusted_probability > rhs->adjusted_probability) {
     return 1;
   } else if (lhs->adjusted_probability < rhs->adjusted_probability) {
@@ -368,11 +382,16 @@ push_node(struct lattice_info* info, struct lattice_node* new_node,
     print_lattice_node(info, new_node);
   }
 
+  assert(position >= 0);
+  if (position >= info->lattice_node_len) {
+    anthy_log(0, "info->lattice_node_list[%d] is not allocated\n", position);
+    return;
+  }
   /* 先頭のnodeが無ければ無条件に追加 */
   node = info->lattice_node_list[position].head;
   if (!node) {
     info->lattice_node_list[position].head = new_node;
-    info->lattice_node_list[position].nr_nodes ++;
+    info->lattice_node_list[position].nr_nodes++;
     return;
   }
 
@@ -406,7 +425,7 @@ push_node(struct lattice_info* info, struct lattice_node* new_node,
 
   /* 最後のノードの後ろに追加 */
   node->next = new_node;
-  info->lattice_node_list[position].nr_nodes ++;
+  info->lattice_node_list[position].nr_nodes++;
 }
 
 /* 一番確率の低いノードを消去する*/
@@ -418,6 +437,10 @@ remove_min_node(struct lattice_info *info, struct node_list_head *node_list)
   struct lattice_node* min_node = node;
   struct lattice_node* previous_min_node = NULL;
 
+  if (!min_node) {
+      anthy_log(0, "No min_node\n");
+      return;
+  }
   /* 一番確率の低いノードを探す */
   while (node) {
     if (cmp_node(node, min_node) < 0) {
@@ -435,7 +458,7 @@ remove_min_node(struct lattice_info *info, struct node_list_head *node_list)
     node_list->head = min_node->next;
   }
   release_lattice_node(info, min_node);
-  node_list->nr_nodes --;
+  node_list->nr_nodes--;
 }
 
 /* いわゆるビタビアルゴリズムを使用して経路を選ぶ */
@@ -446,6 +469,10 @@ choose_path(struct lattice_info* info, int to)
   struct lattice_node* node;
   struct lattice_node* best_node = NULL;
   int last = to;
+  if (last >= info->lattice_node_len) {
+    anthy_log(0, "info->lattice_node_list[%d] is not allocated\n", last);
+    return;
+  }
   while (!info->lattice_node_list[last].head) {
     /* 最後の文字まで遷移していなかったら後戻り */
     --last;
@@ -492,6 +519,11 @@ build_graph(struct lattice_info* info, int from, int to)
    * indexからの遷移が入っているのではない
    */
 
+  if (to >= info->lattice_node_len || from < 0) {
+    anthy_log(0, "info->lattice_node_list[%d] is not allocated: %d\n",
+    to, from);
+    return;
+  }
   /* 全ての遷移を左から試す */
   for (i = from; i < to; ++i) {
     for (left_node = info->lattice_node_list[i].head; left_node;
diff --git a/src-splitter/metaword.c b/src-splitter/metaword.c
index ad98d36..4a5cc0c 100644
--- a/src-splitter/metaword.c
+++ b/src-splitter/metaword.c
@@ -10,6 +10,7 @@
  * Copyright (C) 2000-2006 TABATA Yusuke
  * Copyright (C) 2004-2006 YOSHIDA Yuichi
  * Copyright (C) 2000-2003 UGAWA Tomoharu
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  */
 #include <stdlib.h>
 #include <stdio.h>
@@ -462,10 +463,15 @@ try_combine_number(struct splitter_context *sc,
     /* #NNは対象外 */
     if (scos2 == SCOS_NONE) return;
     /*
-       左mwの種類によって、後ろにつくことができる右mwの種類が変わる
-       例えば一〜九の後ろには万〜九万、億〜九億しかつくことができないが、
-       十〜九十の後ろには、あわせて一〜九などもつくことができる
+     * 左mwの種類によって、後ろにつくことができる右mwの種類が変わる
+     * 例えば一〜九の後ろには万〜九万、億〜九億しかつくことができないが、
+     * 十〜九十の後ろには、あわせて一〜九などもつくことができる
+     * 漢数字、アラビア数字、全角半角切替え
+     * GCC 11.0.1 reports this statement may fall through because of no break
+     * in case statement with "-Wimplicit-fallthrough" option.
      */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
     switch (scos1) {
     case SCOS_N1:
       if (scos2 == SCOS_N1) return; /* 後ろに一〜九がついてはいけない */
@@ -482,6 +488,7 @@ try_combine_number(struct splitter_context *sc,
     default:
       return;
     }
+#pragma GCC diagnostic pop
 
     if (recursive) {
       combined_mw = anthy_do_cons_metaword(sc, MW_NUMBER, mw1, mw2);
@@ -569,9 +576,6 @@ make_dummy_metaword(struct splitter_context *sc, int from,
   n->from = from;
   n->len = len;
   n->score = 3 * score * len / orig_len;
-  if (mw) {
-    mw->nr_parts = 0;
-  }
   anthy_commit_meta_word(sc, n);
 }
 
@@ -695,8 +699,10 @@ make_ochaire_metaword_all(struct splitter_context *sc)
       len = key->len;
 
       make_ochaire_metaword(sc, i, len);
-      /* 今回見つかった meta_word の次の文字から始める */
-      i += len - 1;
+      /* 今回見つかった meta_word の次の文字から始める
+       * `i` should not be touched if `break` is called.
+       */
+      /* i += len - 1; */
       break;
     }
   }
diff --git a/src-splitter/segclass.c b/src-splitter/segclass.c
index 3176a42..363efc4 100644
--- a/src-splitter/segclass.c
+++ b/src-splitter/segclass.c
@@ -1,3 +1,6 @@
+/*
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
+ */
 #include <string.h>
 
 #include <anthy/splitter.h>
@@ -31,7 +34,6 @@ anthy_set_seg_class(struct word_list* wl)
 
   head_pos = wl->head_pos;
   dc = wl->part[PART_DEPWORD].dc;
-  seg_class = SEG_HEAD;
 
   if (wl->part[PART_CORE].len == 0) {
     seg_class = SEG_BUNSETSU;
diff --git a/src-splitter/splitter.c b/src-splitter/splitter.c
index d35ea19..bccaab8 100644
--- a/src-splitter/splitter.c
+++ b/src-splitter/splitter.c
@@ -13,6 +13,7 @@
  * Copyright (C) 2004 YOSHIDA Yuichi
  * Copyright (C) 2000-2004 TABATA Yusuke
  * Copyright (C) 2000-2001 UGAWA Tomoharu
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  *
  * $Id: splitter.c,v 1.48 2002/11/18 11:39:18 yusuke Exp $
  */
@@ -93,6 +94,10 @@ alloc_char_ent(xstr *xs, struct splitter_context *sc)
   sc->char_count = xs->len;
   sc->ce = (struct char_ent*)
     malloc(sizeof(struct char_ent)*(xs->len + 1));
+  if (!sc->ce) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return;
+  }
   for (i = 0; i <= xs->len; i++) {
     sc->ce[i].c = &xs->str[i];
     sc->ce[i].seg_border = 0;
@@ -303,6 +308,7 @@ anthy_init_splitter(void)
   /* 付属語グラフの初期化 */
   if (anthy_init_depword_tab()) {
     anthy_log(0, "Failed to init dependent word table.\n");
+    anthy_quit_depword_tab();
     return -1;
   }
   /**/
diff --git a/src-util/agent.c b/src-util/agent.c
index bb4c2a7..407e046 100644
--- a/src-util/agent.c
+++ b/src-util/agent.c
@@ -6,6 +6,7 @@
  * Funded by IPA未踏ソフトウェア創造事業 2002 2/26
  * Copyright (C) 2001-2002 UGAWA Tomoharu
  * Copyright (C) 2002-2004 TABATA Yusuke,
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  */
 /*
  * *マルチコンテキストの扱いを決めかねている
@@ -23,6 +24,7 @@
 
 #include <anthy/anthy.h>
 #include <anthy/input.h>
+#include <anthy/logger.h>
 
 #include "rkconv.h"
 
@@ -374,9 +376,6 @@ make_hl_command(char *buf)
     cmd->arg[i] = encode_command_arg(p);
   }
   while ((p = strtok(NULL, " \t\r"))) {
-    if (!p) {
-      break;
-    }
     cmd->n_arg++;
     cmd->arg = (char**) realloc(cmd->arg, sizeof(char*) * cmd->n_arg);
     cmd->arg[cmd->n_arg - 1] = encode_command_arg(p);
@@ -516,9 +515,12 @@ proc_connection(void)
     FD_SET(daemon_sock, &rfds);
   }
   max_fd = MAX(conn->rfd, max_fd);
+  assert(conn->rfd >= 0);
   FD_SET(conn->rfd, &rfds);
+  assert(conn->rfd >= 0);
   if (conn->n_wbuf > 0) {
     max_fd = MAX(conn->wfd, max_fd);
+    assert(conn->wfd >= 0);
     FD_SET(conn->wfd, &wfds);
   }
 
@@ -569,7 +571,6 @@ AGAIN:
   }
 
   while (1) {
-
     char* p;
     for (p = conn->rbuf; p < conn->rbuf + conn->n_rbuf; p++) {
       if (*p == '\n') {
@@ -583,11 +584,9 @@ AGAIN:
 	}
       }
     }
-
     if (proc_connection() == -1) {
       return NULL;
     }
-
   }
 }
 
@@ -750,6 +749,10 @@ new_input_context(int id)
 
   ictxl =
     (struct input_context_list*) malloc(sizeof (struct input_context_list));
+  if (!ictxl) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return;
+  }
   ictxl->id = id;
   ictxl->ictx = anthy_input_create_context(config);
   ictxl->next = ictx_list;
@@ -762,6 +765,8 @@ get_current_input_context(void)
   if (ictx_list == NULL)
     new_input_context(0);
 
+  if (!ictx_list)
+    return NULL;
   return ictx_list->ictx;
 }
 
@@ -817,9 +822,16 @@ cmdh_release_input_context(struct command* cmd)
 static void
 cmdh_change_toggle(struct command *cmd)
 {
-  int toggle = cmd->arg[0][0];
+  int toggle;
   int ret;
 
+  assert(cmd->arg);
+  if (!cmd->arg[0]) {
+    anthy_log(0, "cmdh_change_toggle should have one argument.\n");
+    send_error();
+    return;
+  }
+  toggle = cmd->arg[0][0];
   ret = anthy_input_edit_toggle_config(config, toggle);
 
   if (ret != 0) {
@@ -833,6 +845,7 @@ cmdh_change_toggle(struct command *cmd)
 static void
 cmdh_map_clear(struct command *cmd)
 {
+  assert(cmd->arg);
   anthy_input_clear_rk_config(config, atoi(cmd->arg[0]));
   anthy_input_change_config(config);
   send_ok();
@@ -841,6 +854,7 @@ cmdh_map_clear(struct command *cmd)
 static void
 cmdh_set_break_into_roman(struct command *cmd)
 {
+  assert(cmd->arg);
   anthy_input_break_into_roman_config(config, atoi(cmd->arg[0]));
   anthy_input_change_config(config);
   send_ok();
@@ -849,6 +863,7 @@ cmdh_set_break_into_roman(struct command *cmd)
 static void
 cmdh_set_preedit_mode(struct command *cmd)
 {
+  assert(cmd->arg);
   anthy_input_preedit_mode_config(config, atoi(cmd->arg[0]));
   anthy_input_change_config(config);
   send_ok();
@@ -857,10 +872,12 @@ cmdh_set_preedit_mode(struct command *cmd)
 static void
 cmdh_map_edit(struct command* cmd)
 {
-  /* MAP,from,to */
-  int map_no = atoi(cmd->arg[0]);
+  int map_no;
   int ret;
 
+  assert(cmd->arg);
+  /* MAP,from,to */
+  map_no = atoi(cmd->arg[0]);
   ret = anthy_input_edit_rk_config(config, map_no,
 				   cmd->arg[1], cmd->arg[2], NULL);
 
@@ -879,6 +896,7 @@ cmdh_map_select(struct anthy_input_context* ictx,
   char* map_name;
   int map_no;
 
+  assert(cmd->arg);
   map_name = cmd->arg[0];
   if (strcmp(map_name, "alphabet") == 0)
     map_no = ANTHY_INPUT_MAP_ALPHABET;
@@ -906,6 +924,7 @@ cmdh_get_candidate(struct anthy_input_context* ictx,
   struct anthy_input_segment* seg;
   int cand_no;
 
+  assert(cmd->arg);
   cand_no = atoi(cmd->arg[0]);
 
   seg = anthy_input_get_candidate(ictx, cand_no);
@@ -924,6 +943,7 @@ cmdh_select_candidate(struct anthy_input_context* ictx,
   int ret;
   int cand_no;
 
+  assert(cmd->arg);
   cand_no = atoi(cmd->arg[0]);
   ret = anthy_input_select_candidate(ictx, cand_no);
   if (ret < 0) {
@@ -937,20 +957,25 @@ static void
 cmd_shift_arrow(struct anthy_input_context* ictx,
 		struct command* cmd)
 {
-  int lr = atoi(cmd->arg[0]);
+  int lr;
+  assert(cmd->arg);
+  lr = atoi(cmd->arg[0]);
   anthy_input_resize(ictx, lr);
 }
 
 static void
 cmd_arrow(struct anthy_input_context* ictx, struct command* cmd)
 {
-  int lr = atoi(cmd->arg[0]);
+  int lr;
+  assert(cmd->arg);
+  lr = atoi(cmd->arg[0]);
   anthy_input_move(ictx, lr);
 }
 
 static void
 cmd_key(struct anthy_input_context* ictx, struct command* cmd)
 {
+  assert(cmd->arg);
   anthy_input_str(ictx, cmd->arg[0]);
 }
 
@@ -1137,7 +1162,10 @@ main(int argc, char **argv)
     anthy_quit();
   } else {
     config = anthy_input_create_config();
-    conn = (struct connection*) malloc(sizeof(struct connection));
+    if (!(conn = (struct connection*) malloc(sizeof(struct connection)))) {
+      anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+      return 1;
+    }
     conn->rbuf = NULL;
     conn->n_rbuf = 0;
     conn->s_rbuf = 0;
diff --git a/src-util/convdb.c b/src-util/convdb.c
index 0d9dd1d..df240d6 100644
--- a/src-util/convdb.c
+++ b/src-util/convdb.c
@@ -2,6 +2,7 @@
  * 変換エンジンの内部情報を使うため、意図的に
  * layer violationを放置している。
  *
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  */
 #include <stdio.h>
 #include <string.h>
@@ -77,8 +78,8 @@ do_find_conv_res(struct res_db *db, const char *src, const char *res)
 
   for (cr = db->res_list.next; cr; cr = cr->next) {
     if (((!cr->res_str && !res) ||
-	 !strcmp(cr->res_str, res)) &&
-	!strcmp(cr->src_str, src)) {
+        (cr->res_str && res && !strcmp(cr->res_str, res))) &&
+        (cr->src_str && src && !strcmp(cr->src_str, src))) {
       return cr;
     }
   }
@@ -235,6 +236,7 @@ read_db(struct res_db *db, const char *fn)
   while (fgets(line, 1024, fp)) {
     parse_line(db, line);
   }
+  fclose(fp);
 }
 
 static void
@@ -461,7 +463,7 @@ print_segment_info(int is_negative,
   struct feature_list fl;
   struct cand_ent *ce =  selected_candidate(seg);
   int nr_indep = 0;
-  const char *prefix = get_prefix(is_negative);
+  const char *prefix = NULL;
 
   anthy_feature_list_init(&fl);
   set_features(&fl, prev_seg, seg);
diff --git a/src-util/dic-tool.c b/src-util/dic-tool.c
index d7f8b2e..78d01bc 100644
--- a/src-util/dic-tool.c
+++ b/src-util/dic-tool.c
@@ -14,7 +14,7 @@
  * Funded by IPA未踏ソフトウェア創造事業 2001 9/22
  *
  * Copyright (C) 2000-2007 TABATA Yusuke
- * Copyright (C) 2020 Takao Fujiwara
+ * Copyright (C) 2020-2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  */
 /*
   This library is free software; you can redistribute it and/or
@@ -31,6 +31,7 @@
   License along with this library; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
  */
+#include <assert.h>
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -40,6 +41,7 @@
 #include <anthy/anthy.h>
 #include <anthy/diclib.h>
 #include <anthy/dicutil.h>
+#include <anthy/logger.h>
 /**/
 #include <anthy/textdict.h>
 #include <anthy/xstr.h>
@@ -121,16 +123,25 @@ static FILE *
 open_typetab(void)
 {
   FILE *fp;
-  char *fn;
+  char *fn, *tmp;
   fp = fopen(TYPETAB, "r");
   if (fp) {
     return fp;
   }
-  fn = strdup(anthy_dic_util_get_anthydir());
-  fn = realloc(fn, strlen(fn) + strlen(TYPETAB) + 4);
+  if (!(fn = strdup(anthy_dic_util_get_anthydir()))) {
+    anthy_log(0, "Could not find ANTHYDIR in conf file.\n");
+    return NULL;
+  }
+  if (!(tmp = realloc(fn, strlen(fn) + strlen(TYPETAB) + 4))) {
+    anthy_log(0, "Could not realloc TYPETAB.\n");
+    /* free(fn) is freed twice. */
+    return NULL;
+  }
+  fn = tmp;
   strcat(fn, "/");
   strcat(fn, TYPETAB);
   fp = fopen(fn, "r");
+  free(fn);
   return fp;
 }
 
@@ -142,11 +153,27 @@ open_usage_file(void)
   fp = fopen(USAGE_TEXT, "r");
   if (!fp) {
     /* インストールされたものを使用 */
-    char *fn;
-    fn = strdup(anthy_dic_util_get_anthydir());
-    fn = realloc(fn, strlen(fn) + strlen(USAGE_TEXT) + 10);
+    char *fn = NULL, *tmp;
+    if (!(fn = strdup(anthy_dic_util_get_anthydir()))) {
+      anthy_log(0, "Could not find ANTHYDIR in conf file.\n");
+      return NULL;
+    }
+    if (!(tmp = realloc(fn, strlen(fn) + strlen(USAGE_TEXT) + 10))) {
+      anthy_log(0, "Could not realloc USAGE_TEXT.\n");
+      /* CPPCHECK_WARNING and CLANG_WARNING are conflicted.
+       * CPPCHECK_WARNING reports: Common realloc mistake:
+       *     'fn' nulled but not freed upon failure
+       * also CLANG_WARNING reports: Potential leak of memory ponted to by 'fn'
+       * On the other hand,
+       * CLANG_WARNING reports: 'fn' is freed twice.
+       */
+      free(fn);
+      return NULL;
+    }
+    fn = tmp;
     strcat(fn, "/" USAGE_TEXT);
     fp = fopen(fn, "r");
+    free(fn);
   }
   return fp;
 }
@@ -263,7 +290,10 @@ read_typetab_var(struct var *head, FILE *fp, int table)
     return -1;
   }
 
-  v = malloc(sizeof(struct var));
+  if (!(v = malloc(sizeof(struct var)))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return -1;
+  }
   if (encoding == ANTHY_EUC_JP_ENCODING && table) {
     /* UTF-8 */
     v->var_name = anthy_conv_utf8_to_euc(var);
@@ -281,6 +311,22 @@ read_typetab_var(struct var *head, FILE *fp, int table)
   return 0;
 }
 
+static void
+free_typetab_var (struct var *head)
+{
+  struct var *v = head;
+  while (v) {
+    struct var *prev;
+    free (v->var_name);
+    free (v->val);
+    prev = v;
+    v = v->next;
+    /* head is not allocated */
+    if (prev != head)
+      free (prev);
+  }
+}
+
 static int
 read_typetab_entry(FILE *fp)
 {
@@ -315,6 +361,7 @@ read_typetab(void)
     exit(1);
   }
   while (!read_typetab_entry(fp));
+  fclose(fp);
 }
 
 static struct trans_tab *
@@ -416,13 +463,16 @@ find_wt(void)
   struct var v;
   struct trans_tab *t;
   v.next = 0;
+  memset(&v, 0, sizeof(struct var));
   while(!read_typetab_var(&v, fp_in, 0));
   for (t = trans_tab_list.next; t; t = t->next) {
     if (var_list_subset_p(&t->var_list, &v) &&
-	var_list_subset_p(&v, &t->var_list)) {
+        var_list_subset_p(&v, &t->var_list)) {
+      free_typetab_var(&v);
       return t->type_name;
     }
   }
+  free_typetab_var(&v);
   return NULL;
 }
 
@@ -493,17 +543,29 @@ load_text_dic (void)
     return;
   }
   do {
-    yomi = strdup (anthy_priv_dic_get_index (buf, LINE_SIZE));
+    if (!(yomi = strdup (anthy_priv_dic_get_index (buf, LINE_SIZE)))) {
+      anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+      continue;
+    }
     if (*yomi == '#') {
       free (yomi);
       continue;
     }
     if (!dict_head) {
-      d = dict_head = calloc (sizeof (struct dict_entry), 1);
+      if (!(d = dict_head = calloc (sizeof (struct dict_entry), 1))) {
+        anthy_log(0, "Failed calloc in %s:%d\n", __FILE__, __LINE__);
+        free(yomi);
+        break;
+      }
     } else {
-      d->next = calloc (sizeof (struct dict_entry), 1);
+      if (!(d->next = calloc (sizeof (struct dict_entry), 1))) {
+        anthy_log(0, "Failed calloc in %s:%d\n", __FILE__, __LINE__);
+        free(yomi);
+        break;
+      }
       d = d->next;
     }
+    assert(d);
     d->yomi = yomi;
     d->word = strdup (anthy_priv_dic_get_word (buf, LINE_SIZE));
     d->wtype = strdup (anthy_priv_dic_get_wtype (buf, LINE_SIZE));
diff --git a/src-util/egg.c b/src-util/egg.c
index f9cdb0a..b1ca871 100644
--- a/src-util/egg.c
+++ b/src-util/egg.c
@@ -1,5 +1,6 @@
 /*
  * Copyright (C) 2002 The Free Software Initiative of Japan
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  * Author: NIIBE Yutaka
  */
 
@@ -7,11 +8,14 @@
  * ANTHY Low Level Agent
  */
 
+#include <limits.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include <anthy/anthy.h>
+#include <anthy/logger.h>
 
 #include "config.h"
 
@@ -126,6 +130,11 @@ begin_conversion (struct context *c, const char *input)
   seg_num = get_number_of_segments (c);
   if (seg_num >= c->sellen) {
     c->sellen *= 2;
+    if (sizeof(int) * c->sellen >= INT_MAX || c->sellen < 0) {
+      anthy_log(0, "Exceed max allocation size: %lu >= %d\n",
+                (unsigned long)sizeof(int) * c->sellen, INT_MAX);
+      return -1;
+    }
     c->selection = realloc (c->selection, c->sellen);
     if (c->selection == NULL) { /* Fatal */
       c->sellen = -1;
diff --git a/src-util/input.c b/src-util/input.c
index 5626115..030e3d8 100644
--- a/src-util/input.c
+++ b/src-util/input.c
@@ -5,6 +5,7 @@
  *
  * Funded by IPA未踏ソフトウェア創造事業 2002 1/23
  * Copyright (C) 2001-2002 UGAWA Tomoharu
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmai.com>
  *
  * $Id: input.c,v 1.25 2002/11/16 03:35:21 yusuke Exp $
  *
@@ -21,6 +22,7 @@
 
 #include <anthy/anthy.h>
 #include <anthy/input.h>
+#include <anthy/logger.h>
 
 #include "rkconv.h"
 #include "rkhelper.h"
@@ -332,6 +334,10 @@ cmdh_get_candidate(struct anthy_input_context* ictx, int cand_no)
 
   seg = (struct anthy_input_segment*)
     malloc(sizeof(struct anthy_input_segment));
+  if (!seg) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return NULL;
+  }
   len = anthy_get_segment(ictx->actx, cs->index, cand_no, NULL, 0);
   seg->str = (char*) malloc(len + 1);
   anthy_get_segment(ictx->actx, cs->index, cand_no, seg->str, len + 1);
@@ -394,6 +400,10 @@ do_cmd_push_key(struct anthy_input_context* ictx, const char* str)
 {
   const char* p;
 
+  if (!str) {
+    anthy_log(0, "str should not be null in %s:%d\n", __FILE__, __LINE__);
+    return;
+  }
   for (p = str; *p; p++) {
     if (isspace((int)(unsigned char) *p) && *p != ' ')
       continue;
@@ -551,7 +561,10 @@ cmd_resize(struct anthy_input_context* ictx, int d)
     if (as->next == NULL) {
       struct a_segment* as2;
 
-      as2 = (struct a_segment*) malloc(sizeof(struct a_segment));
+      if (!(as2 = (struct a_segment*) malloc(sizeof(struct a_segment)))) {
+        anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+        break;
+      }
       as2->index = i;
       as2->prev = as;
       as->next = as2;
@@ -773,6 +786,10 @@ anthy_input_create_context(struct anthy_input_config* cfg)
 
   ictx =
     (struct anthy_input_context*) malloc(sizeof(struct anthy_input_context));
+  if (!ictx) {
+      anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+      return NULL;
+  }
   ictx->state = ANTHY_INPUT_ST_NONE;
   ictx->rkctx = rk_context_create(cfg->break_into_roman);
   for (i = 0; i < NR_RKMAP; i++)
@@ -1180,6 +1197,8 @@ alloc_segment(int flag, int len, int noconv_len)
   struct anthy_input_segment *seg;
   seg = (struct anthy_input_segment*)
     malloc(sizeof(struct anthy_input_segment));
+  if (!seg)
+    return NULL;
   seg->flag = flag;
   seg->cand_no = -1;
   seg->nr_cand = -1;
@@ -1207,6 +1226,11 @@ get_edit_mode_preedit(struct anthy_input_context* ictx,
   if (ictx->n_hbuf > 0) {
     *p = alloc_segment(ANTHY_INPUT_SF_EDITING, ictx->n_hbuf + 1,
 		       ictx->n_hbuf);
+    if (!(*p) || !((*p)->str)) {
+      anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+      ictx->n_hbuf = 0;
+      return;
+    }
 
     memcpy((*p)->str, ictx->hbuf, ictx->n_hbuf);
     (*p)->str[ictx->n_hbuf] = '\0';
@@ -1216,7 +1240,11 @@ get_edit_mode_preedit(struct anthy_input_context* ictx,
   if (ictx->cfg->preedit_mode) {
     len = rk_partial_result(ictx->rkctx, NULL, 0);
     if (len > 1) {
-      *p = alloc_segment(ANTHY_INPUT_SF_PENDING, len, len - 1);
+      if (!(*p = alloc_segment(ANTHY_INPUT_SF_PENDING, len, len - 1))) {
+        anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+        pedit->cur_segment = NULL;
+        return;
+      }
 
       rk_partial_result(ictx->rkctx, (*p)->str, len);
       p = &(*p)->next;
@@ -1224,7 +1252,11 @@ get_edit_mode_preedit(struct anthy_input_context* ictx,
   } else {
     len = rk_get_pending_str(ictx->rkctx, NULL, 0);
     if (len > 1) {
-      *p = alloc_segment(ANTHY_INPUT_SF_PENDING, len, len - 1);
+      if (!(*p = alloc_segment(ANTHY_INPUT_SF_PENDING, len, len - 1))) {
+        anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+        pedit->cur_segment = NULL;
+        return;
+      }
 
       rk_get_pending_str(ictx->rkctx, (*p)->str, len);
       p = &(*p)->next;
@@ -1232,7 +1264,11 @@ get_edit_mode_preedit(struct anthy_input_context* ictx,
   }
 
   /* cursor */
-  *p = alloc_segment(ANTHY_INPUT_SF_CURSOR, 0, 0);
+  if (!(*p = alloc_segment(ANTHY_INPUT_SF_CURSOR, 0, 0))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    pedit->cur_segment = NULL;
+    return;
+  }
   pedit->cur_segment = *p;
   p = &(*p)->next;
 
@@ -1241,8 +1277,12 @@ get_edit_mode_preedit(struct anthy_input_context* ictx,
     *p = alloc_segment(ANTHY_INPUT_SF_EDITING,
 		       ictx->n_hbuf_follow + 1,
 		       ictx->n_hbuf_follow);
-    memcpy((*p)->str, ictx->hbuf_follow, ictx->n_hbuf_follow);
-    (*p)->str[ictx->n_hbuf_follow] = '\0';
+    if (!(*p) || !((*p)->str)) {
+      anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    } else {
+      memcpy((*p)->str, ictx->hbuf_follow, ictx->n_hbuf_follow);
+      (*p)->str[ictx->n_hbuf_follow] = '\0';
+    }
   }
 }
 
@@ -1253,14 +1293,21 @@ anthy_input_get_preedit(struct anthy_input_context* ictx)
 
   pedit = (struct anthy_input_preedit*)
     malloc(sizeof(struct anthy_input_preedit));
+  if (!pedit) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return NULL;
+  }
 
   pedit->state = ictx->state;
 
   /* 未コミットの文字列 */
   if (ictx->n_commit > 0) {
-    pedit->commit = (char*) malloc(ictx->n_commit + 1);
-    memcpy(pedit->commit, ictx->commit, ictx->n_commit);
-    pedit->commit[ictx->n_commit] = '\0';
+    if (!(pedit->commit = (char*) malloc(ictx->n_commit + 1))) {
+      anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    } else {
+      memcpy(pedit->commit, ictx->commit, ictx->n_commit);
+      pedit->commit[ictx->n_commit] = '\0';
+    }
     ictx->n_commit = 0;
   } else {
     pedit->commit = NULL;
@@ -1268,9 +1315,12 @@ anthy_input_get_preedit(struct anthy_input_context* ictx)
 
   /* カットバッファの文字列 */
   if(ictx->n_cut > 0) {
-    pedit->cut_buf = (char*) malloc(ictx->n_cut + 1);
-    memcpy(pedit->cut_buf, ictx->cut, ictx->n_cut);
-    pedit->cut_buf[ictx->n_cut] = '\0';
+    if (!(pedit->cut_buf = (char*) malloc(ictx->n_cut + 1))) {
+      anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    } else {
+      memcpy(pedit->cut_buf, ictx->cut, ictx->n_cut);
+      pedit->cut_buf[ictx->n_cut] = '\0';
+    }
     ictx->n_cut = 0;
   } else {
     pedit->cut_buf = NULL;
@@ -1299,7 +1349,10 @@ anthy_input_get_preedit(struct anthy_input_context* ictx)
 				       NTH_UNCONVERTED_CANDIDATE,
 				       NULL, 0);
 	len = anthy_get_segment(ictx->actx, as->index, as->cand, NULL, 0);
-	*p = alloc_segment(ANTHY_INPUT_SF_NONE, len + 1, noconv_len);
+	if (!(*p = alloc_segment(ANTHY_INPUT_SF_NONE, len + 1, noconv_len))) {
+          anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+          return pedit;
+	}
 
 	anthy_get_segment(ictx->actx, as->index, as->cand, (*p)->str, len + 1);
 	(*p)->cand_no = as->cand;
@@ -1324,6 +1377,10 @@ anthy_input_get_preedit(struct anthy_input_context* ictx)
 
 	      p = &(*p)->next;
 	      *p = alloc_segment(ANTHY_INPUT_SF_FOLLOWING, len + 1, len);
+	      if (!(*p) || !((*p)->str)) {
+                anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+                break;
+	      }
 	      for (as1 = as->next, s = (*p)->str; as1; as1 = as1->next) {
 		anthy_get_segment(ictx->actx, as1->index,
 				  NTH_UNCONVERTED_CANDIDATE,
@@ -1490,6 +1547,10 @@ anthy_input_create_config(void)
   struct anthy_input_config* cfg;
 
   cfg = (struct anthy_input_config*) malloc(sizeof(struct anthy_input_config));
+  if (!cfg) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return NULL;
+  }
 
   cfg->rk_option = anthy_input_create_rk_option();
   cfg->break_into_roman = 0;
diff --git a/src-util/rkconv.c b/src-util/rkconv.c
index acbb1ef..435dc6b 100644
--- a/src-util/rkconv.c
+++ b/src-util/rkconv.c
@@ -7,12 +7,16 @@
  * $Id: rkconv.c,v 1.16 2002/11/16 03:35:21 yusuke Exp $
  *
  * Copyright (C) 2001-2002 UGAWA Tomoharu
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  *
  */
+#include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
+#include <anthy/logger.h>
+
 #include "rkconv.h"
 
 #define MAX_CONV_CHARS  1024
@@ -193,7 +197,7 @@ rk_slr_closure_create(struct rk_rule_set* rs,
     struct rk_rule* r;
     int c;
     r = rs->rules + i;
-    if (pflen > 0 && strncmp(prefix, r->lhs, pflen) != 0)
+    if (pflen > 0 && strncmp(prefix ? prefix : "", r->lhs, pflen) != 0)
       continue;
 
     c = r->lhs[pflen] & 0x7f;
@@ -341,9 +345,13 @@ rk_convert_iterative(struct rk_conv_context* cc, int c,
 static void
 brk_roman_init(struct rk_conv_context *rkctx)
 {
-  rkctx->brk_roman= (struct break_roman *)malloc(sizeof(struct break_roman));
-  rkctx->brk_roman->pending=NULL;
-  rkctx->brk_roman->pending_size=0;
+  rkctx->brk_roman = (struct break_roman *)malloc(sizeof(struct break_roman));
+  if (!rkctx->brk_roman) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return;
+  }
+  rkctx->brk_roman->pending = NULL;
+  rkctx->brk_roman->pending_size = 0;
 }
 
 static void
@@ -354,10 +362,10 @@ brk_roman_free(struct rk_conv_context *rkctx)
   if(!br)
     return;
 
-  if (br->pending) {
-    free(br->pending);
-  }
+  free(br->pending);
+  br->pending = NULL;
   free(br);
+  rkctx->brk_roman = NULL;
 }
 
 
@@ -374,8 +382,7 @@ brk_roman_save_pending(struct rk_conv_context *rkctx)
 
   if(br->pending_size < len){
     br->pending_size=len;
-    if(br->pending)
-      free(br->pending);
+    free(br->pending);
     br->pending=(char *)malloc(len);
   }
 
@@ -386,7 +393,12 @@ brk_roman_save_pending(struct rk_conv_context *rkctx)
 static void
 brk_roman_set_decided_len(struct rk_conv_context *rkctx,int len)
 {
-  struct break_roman *br=rkctx->brk_roman;
+  struct break_roman *br;
+  if (!rkctx) {
+    anthy_log(0, "Failed rkctx != NULL in %s:%d\n", __FILE__, __LINE__);
+    return;
+  }
+  br=rkctx->brk_roman;
 
   if(!br)
     return;
@@ -447,6 +459,10 @@ int
 rk_push_key(struct rk_conv_context* cc, int c)
 {
   int increased_length;
+  if (!cc) {
+    anthy_log(0, "Failed cc != NULL in %s:%d\n", __FILE__, __LINE__);
+    return -1;
+  }
   c &= 0x7f;
   if (cc->cur_state == NULL)
     return -1;
@@ -527,6 +543,10 @@ rk_select_map(struct rk_conv_context* cc, struct rk_map* map)
 {
   struct rk_map* old_map;
 
+  if (!cc) {
+    anthy_log(0, "Failed cc != NULL in %s:%d\n", __FILE__, __LINE__);
+    return NULL;
+  }
   cc->old_map_no = cc->map_no;
   old_map = cc->map;
   if (old_map) {
@@ -557,6 +577,10 @@ rk_get_pending_str(struct rk_conv_context* cc, char* buf, int size)
 
   if (size <= 0)
     return strlen(p) + 1;
+  if (!buf) {
+    anthy_log(0, "Failed buf != NULL in %s:%d\n", __FILE__, __LINE__);
+    return 0;
+  }
 
   q = buf;
   end = buf + size - 1;
@@ -588,6 +612,7 @@ rk_register_map(struct rk_conv_context* cc, int mapn, struct rk_map* map)
 void
 rk_select_registered_map(struct rk_conv_context* cc, int mapn)
 {
+  assert(cc);
   if (0 <= mapn && mapn < 0 + MAX_MAP_PALETTE) {
     rk_select_map(cc, cc->map_palette[mapn]);
     cc->map_no = mapn;
@@ -663,7 +688,6 @@ rk_sort_rule(const struct rk_rule *src)
  ERROR:
   rules[i].lhs = NULL;
   rk_rules_free(rules);
-  free(rules);
   return NULL;
 }
 
diff --git a/src-worddic/dic_util.c b/src-worddic/dic_util.c
index 3963e8f..9eae864 100644
--- a/src-worddic/dic_util.c
+++ b/src-worddic/dic_util.c
@@ -17,6 +17,7 @@
  * Funded by IPA未踏ソフトウェア創造事業 2001 10/24
  *
  * Copyright (C) 2001-2007 TABATA Yusuke
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  *
  */
 /*
@@ -34,6 +35,7 @@
   License along with this library; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
  */
+#include <assert.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
@@ -41,9 +43,10 @@
 #include <anthy/anthy.h>
 #include <anthy/conf.h>
 #include <anthy/dic.h>
-#include <anthy/texttrie.h>
-#include <anthy/textdict.h>
 #include <anthy/dicutil.h>
+#include <anthy/logger.h>
+#include <anthy/textdict.h>
+#include <anthy/texttrie.h>
 
 #include "dic_main.h"
 #include "dic_personality.h"
@@ -291,6 +294,10 @@ anthy_priv_dic_get_index(char *buf, int len)
   } else {
     src_buf = strdup(src_buf);
   }
+  if (!src_buf) {
+    anthy_log(0, "Failed src_buf != NULL in %s:%d\n", __FILE__, __LINE__);
+    return NULL;
+  }
   /* 最初の空白か\0までをコピーする */
   for (i = 0; src_buf[i] && src_buf[i] != ' '; i++) {
     if (i >= len - 1) {
@@ -356,6 +363,7 @@ anthy_priv_dic_get_word(char *buf, int len)
   }
   /* 品詞の後ろにある単語を取り出す */
   s = strchr(v, ' ');
+  assert(s);
   s++;
   if (!word_iterator.in_tt && dic_util_encoding == ANTHY_EUC_JP_ENCODING) {
     s = anthy_conv_utf8_to_euc(s);
@@ -441,6 +449,10 @@ find_same_word(char *idx_buf, const char *yomi,
 	       const char *word, const char *wt_name, int yomi_len)
 {
   int found = 0;
+  if (!idx_buf) {
+    anthy_log(0, "Failed idx_buf != NULL in %s:%d\n", __FILE__, __LINE__);
+    return found;
+  }
   sprintf(idx_buf, "%s%s ",
 	  encoding_prefix(dic_util_encoding),
 	  yomi);
@@ -456,6 +468,13 @@ find_same_word(char *idx_buf, const char *yomi,
       break;
     }
     /* texttrieにアクセスして、見出語以外も一致しているかをチェック */
+    /* 単語を読み出して登録
+     * GCC 11.0.1 reports double-'free' of 'v'
+     * in case statement with "-Wanalyzer-double-free" option
+     * but 'v' is always allocated newly.
+     */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wanalyzer-double-free"
     v = anthy_trie_find(anthy_private_tt_dic, idx_buf);
     if (v) {
       found = dup_word_check(v, word, wt_name);
@@ -464,6 +483,7 @@ find_same_word(char *idx_buf, const char *yomi,
 	break;
       }
     }
+#pragma GCC diagnostic pop
   } while (anthy_trie_find_next_key(anthy_private_tt_dic,
 				    idx_buf, yomi_len + 12));
 
@@ -565,9 +585,7 @@ do_search(FILE *fp, const char *word)
       continue;
     }
     if (!strncasecmp(buf, word, len)) {
-      if (res) {
-	free(res);
-      }
+      free(res);
       res = strdup(buf);
     }
   }
diff --git a/src-worddic/ext_ent.c b/src-worddic/ext_ent.c
index 45ecdd3..8701d43 100644
--- a/src-worddic/ext_ent.c
+++ b/src-worddic/ext_ent.c
@@ -5,6 +5,7 @@
  *
  * Copyright (C) 2001-2005 TABATA Yusuke
  * Copyright (C) 2004-2005 YOSHIDA Yuichi
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  *
  */
 /*
@@ -22,11 +23,13 @@
   License along with this library; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
  */
+#include <assert.h>
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
 #include <anthy/anthy.h> /* for ANTHY_*_ENCODING */
 #include <anthy/conf.h>
+#include <anthy/logger.h>
 #include <anthy/xstr.h>
 #include <anthy/xchar.h>
 #include "dic_main.h"
@@ -201,6 +204,8 @@ compose_num_component(xstr *xs, long long num)
 {
   int n[4],i;
   int a[4] = { 0 , KJ_10, KJ_100, KJ_1000};
+  xstr *tmp;
+   assert(xs);
   for (i = 0; i < 4; i++) {
     n[i] = num-(num/10)*10;
     num /= 10;
@@ -209,14 +214,17 @@ compose_num_component(xstr *xs, long long num)
   for (i = 3; i > 0; i--) {
     if (n[i] > 0) {
       if (n[i] > 1) {
-	anthy_xstrappend(xs, get_kj_num(n[i]));
+        tmp = anthy_xstrappend(xs, get_kj_num(n[i]));
+	assert(tmp == xs);
       }
-      anthy_xstrappend(xs, a[i]);
+      tmp = anthy_xstrappend(xs, a[i]);
+      assert(tmp == xs);
     }
   }
   /* 1の位 */
   if (n[0]) {
-    anthy_xstrappend(xs, get_kj_num(n[0]));
+    tmp = anthy_xstrappend(xs, get_kj_num(n[0]));
+    assert(tmp == xs);
   }
 }
 
@@ -339,16 +347,20 @@ gen_separated_num(long long num, xstr *dest, int full)
 
   /* 桁数を数える */
   for (tmp = num; tmp != 0; tmp /= 10) {
-    width ++;
+    width++;
   }
   /* 点の数 */
   dot_count = (width - 1) / 3;
   /* 格納するのに必要な文字列を用意する */
   dest->len = dot_count + width;
-  dest->str = malloc(sizeof(xchar)*dest->len);
+  if (!(dest->str = malloc(sizeof(xchar)*dest->len))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    dest->len = 0;
+    return -1;
+  }
 
   /* 右の桁から順に決めていく */
-  for (i = 0, pos = dest->len - 1; i < width; i++, pos --) {
+  for (i = 0, (pos = dest->len - 1) && (pos >= 0); i < width; i++, pos--) {
     int n = num % 10;
     /* カンマを追加 */
     if (i > 0 && (i % 3) == 0) {
@@ -357,7 +369,11 @@ gen_separated_num(long long num, xstr *dest, int full)
       } else {
 	dest->str[pos] = ',';
       }
-      pos --;
+      pos--;
+    }
+    if (pos < 0) {
+      anthy_log(0, "pos %d < 0 in %s:%d\n", pos, __FILE__, __LINE__);
+      break;
     }
     if (full) {
       /* 全角数字 */
@@ -396,7 +412,12 @@ anthy_get_nth_dic_ent_str_of_ext_ent(seq_ent_t se, xstr *xs,
   if (anthy_get_xstr_type(xs) & (XCT_NUM|XCT_WIDENUM)) {
     long long num = anthy_xstrtoll(xs);
     const int base_ents = get_nr_num_ents(num); /* ３桁郵便番号への対応 */
-    /* 漢数字、アラビア数字、全角半角切替え */
+    /* 漢数字、アラビア数字、全角半角切替え
+     * GCC 11.0.1 reports this statement may fall through because of no break
+     * in case statement with "-Wimplicit-fallthrough" option.
+     */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
     switch(nth) {
     case 1:
       /* 全角半角を入れ換えたもの */
@@ -431,6 +452,7 @@ anthy_get_nth_dic_ent_str_of_ext_ent(seq_ent_t se, xstr *xs,
       }
       break;
     }
+#pragma GCC diagnostic pop
     return -1;
   }
   return 0;
diff --git a/src-worddic/feature_set.c b/src-worddic/feature_set.c
index 0af964e..36576e4 100644
--- a/src-worddic/feature_set.c
+++ b/src-worddic/feature_set.c
@@ -3,6 +3,7 @@
  * 素性の番号と意味を隠蔽して管理する
  *
  * Copyright (C) 2006-2007 TABATA Yusuke
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  *
  */
 /*
@@ -20,6 +21,7 @@
   License along with this library; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
  */
+#include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -232,6 +234,11 @@ anthy_find_feature_freq(const void *image,
 
   /* 配列にコピーする */
   nr = anthy_feature_list_nr(fl);
+  /* From anthy_feature_list_add(), nr should <= NR_EM_FEATURES.
+   * And i should be < NR_EM_FEATURES for anthy_feature_list_nth()
+   * which accesses fl->u.index[i].
+   */
+  assert(nr <= NR_EM_FEATURES);
   for (i = 0; i < NR_EM_FEATURES + 2; i++) {
     if (i < nr) {
       f[i] = anthy_feature_list_nth(fl, i);
diff --git a/src-worddic/matrix.c b/src-worddic/matrix.c
index d4627fe..ba65c66 100644
--- a/src-worddic/matrix.c
+++ b/src-worddic/matrix.c
@@ -44,6 +44,7 @@
  *   image[2+image[0] ~ 2+image[0]+image[1]-1] : hashed row array
  *
  * Copyright (C) 2005 TABATA Yusuke
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  *
  */
 /*
@@ -61,12 +62,14 @@
   License along with this library; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
  */
+#include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 
 #include <anthy/diclib.h>
 /* public APIs */
 #include <anthy/matrix.h>
+#include <anthy/logger.h>
 
 /* maximum length allowed for hash chain */
 #define MAX_FAILURE 50
@@ -114,6 +117,8 @@ sparse_array_new(void)
   a->head.next = NULL;
   a->head.orig_next = NULL;
   a->head.index = -1;
+  a->head.ptr = NULL;
+  a->head.value = 0;
   /**/
   a->array_len = 0;
   a->array = NULL;
@@ -182,7 +187,10 @@ sparse_array_try_make_array(struct sparse_array *s)
   struct list_elm *e;
   /* initialize */
   free(s->array);
-  s->array = malloc(sizeof(struct array_elm) * s->array_len);
+  if (!(s->array = malloc(sizeof(struct array_elm) * s->array_len))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return 1;
+  }
   for (i = 0; i < s->array_len; i++) {
     s->array[i].index = -1;
   }
@@ -193,6 +201,7 @@ sparse_array_try_make_array(struct sparse_array *s)
     int n = 0;
     do {
       int h = hash(e->index, s->array_len, n);
+      assert((h >= 0) && (h < s->array_len));
       if (s->array[h].index == -1) {
 	/* find unused element in this array */
 	ok = 1;
@@ -201,7 +210,7 @@ sparse_array_try_make_array(struct sparse_array *s)
 	s->array[h].ptr = e->ptr;
       } else {
 	/* collision */
-	n ++;
+	n++;
 	if (n > MAX_FAILURE) {
 	  /* too much collision */
 	  return 1;
@@ -246,7 +255,7 @@ sparse_array_get(struct sparse_array *s, int index, struct array_elm *arg)
       }
     }
   } else {
-    struct list_elm *e = e = s->head.next;
+    struct list_elm *e = s->head.next;
     while (e) {
       if (e->index == index) {
 	arg->value = e->value;
@@ -287,6 +296,32 @@ sparse_array_get_ptr(struct sparse_array *s, int index)
   return NULL;
 }
 
+static void
+sparse_array_free (struct sparse_array **array)
+{
+  struct list_elm *e;
+
+  assert(array);
+  if (!(*array))
+    return;
+  free ((*array)->array);
+  (*array)->array = NULL;
+  for (e = (*array)->head.next; e;) {
+    struct list_elm *next = e->next;
+    struct sparse_array *sub = e->ptr;
+    sparse_array_free (&sub);
+    e->ptr = NULL;
+    e->next = NULL;
+    free (e);
+    e = next;
+  }
+  (*array)->head.next = NULL;
+  if (!(*array))
+    return;
+  free (*array);
+  *array = NULL;
+}
+
 /**/
 struct sparse_matrix {
   /**/
@@ -320,7 +355,7 @@ find_row(struct sparse_matrix *m, int row, int create)
   /* allocate a new row */
   a = sparse_array_new();
   sparse_array_set(m->row_array, row, 0, a);
-  m->nr_rows ++;
+  m->nr_rows++;
   return a;
 }
 
@@ -339,11 +374,10 @@ int
 anthy_sparse_matrix_get_int(struct sparse_matrix *m, int row, int column)
 {
   struct sparse_array *a;
-  struct list_elm *e;
+  struct list_elm *e = NULL;
   a = find_row(m, row, 1);
-  if (!a) {
+  if (!a)
     return 0;
-  }
   for (e = &a->head; e; e = e->next) {
     if (e->index == column) {
       return e->value;
@@ -378,6 +412,14 @@ anthy_sparse_matrix_make_matrix(struct sparse_matrix *m)
   m->array_length = offset;
 }
 
+/* API */
+void
+anthy_sparse_matrix_free (struct sparse_matrix *m)
+{
+  sparse_array_free (&m->row_array);
+  free (m);
+}
+
 /* API */
 struct matrix_image *
 anthy_matrix_image_new(struct sparse_matrix *s)
@@ -386,15 +428,24 @@ anthy_matrix_image_new(struct sparse_matrix *s)
   int i;
   int offset;
   /**/
-  mi = malloc(sizeof(struct matrix_image));
+  assert(s && s->row_array);
+  if (!(mi = malloc(sizeof(struct matrix_image)))) {
+      anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+      return NULL;
+  }
   mi->size = 2 + s->row_array->array_len * 2 + s->array_length * 2;
-  mi->image = malloc(sizeof(int) * mi->size);
+  if (!(mi->image = malloc(sizeof(int) * mi->size))) {
+      anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+      free(mi);
+      return NULL;
+  }
   mi->image[0] = s->row_array->array_len;
   mi->image[1] = s->array_length;
   /* row index */
   offset = 2;
   for (i = 0; i < s->row_array->array_len; i++) {
     struct array_elm *ae;
+    assert(s->row_array->array);
     ae = &s->row_array->array[i];
     mi->image[offset + i*2] = ae->index;
     mi->image[offset + i*2 + 1] = ae->value;
@@ -405,6 +456,7 @@ anthy_matrix_image_new(struct sparse_matrix *s)
     struct array_elm *ae;
     struct sparse_array *sa;
     int j;
+    assert(s->row_array->array);
     ae = &s->row_array->array[i];
     if (ae->index == -1) {
       continue;
@@ -414,7 +466,10 @@ anthy_matrix_image_new(struct sparse_matrix *s)
       continue;
     }
     for (j = 0; j < sa->array_len; j++) {
-      struct array_elm *cell = &sa->array[j];
+      struct array_elm *cell;
+      assert(sa->array);
+      cell = &sa->array[j];
+      assert(cell);
       mi->image[offset] = cell->index;
       if (cell->index == -1) {
 	mi->image[offset + 1] = -1;
diff --git a/src-worddic/priv_dic.c b/src-worddic/priv_dic.c
index ce0693d..3c3c268 100644
--- a/src-worddic/priv_dic.c
+++ b/src-worddic/priv_dic.c
@@ -5,6 +5,7 @@
  * 未知語を自動的に学習して管理するAPIも持つ。
  *
  * Copyright (C) 2000-2007 TABATA Yusuke
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  */
 /*
   This library is free software; you can redistribute it and/or
@@ -21,6 +22,7 @@
   License along with this library; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
  */
+#include <errno.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <dirent.h>
@@ -44,6 +46,7 @@
 #include <anthy/word_dic.h>
 #include "dic_main.h"
 #include "dic_ent.h"
+#include <src-diclib/diclib_inner.h>
 
 /* 個人辞書 */
 struct text_trie *anthy_private_tt_dic;
@@ -82,17 +85,26 @@ anthy_get_user_dir(int is_old)
 
   if (is_old) {
     hd = anthy_conf_get_str("HOME");
-    old_anthy_private_dir = malloc(strlen(hd) + 10);
+    if (!(old_anthy_private_dir = malloc(strlen(hd) + 10))) {
+      anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+      return NULL;
+    }
     sprintf(old_anthy_private_dir, "%s/.anthy", hd);
     return old_anthy_private_dir;
   }
   xdg = anthy_conf_get_str("XDG_CONFIG_HOME");
   if (xdg && xdg[0]) {
-    anthy_private_dir = malloc(strlen(xdg) + 10);
+    if (!(anthy_private_dir = malloc(strlen(xdg) + 10))) {
+      anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+      return NULL;
+    }
     sprintf(anthy_private_dir, "%s/anthy", xdg);
   } else {
     hd = anthy_conf_get_str("HOME");
-    anthy_private_dir = malloc(strlen(hd) + 15);
+    if (!(anthy_private_dir = malloc(strlen(hd) + 15))) {
+      anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+      return NULL;
+    }
     sprintf(anthy_private_dir, "%s/.config/anthy", hd);
   }
   return anthy_private_dir;
@@ -102,20 +114,18 @@ anthy_get_user_dir(int is_old)
 void
 anthy_check_user_dir(void)
 {
-  struct stat st;
   const char *dn = anthy_get_user_dir(0);
-  if (stat(dn, &st) || !S_ISDIR(st.st_mode)) {
+  /* Use anthy_file_test() and anthy_mkdir_with_parents() since
+   * chmod() after stat() causes a a time-of-check, * time-of-use race
+   * condition (TOCTOU).
+   */
+  if (!anthy_file_test (dn, ANTHY_FILE_TEST_EXISTS | ANTHY_FILE_TEST_IS_DIR)) {
     int r;
-    /*fprintf(stderr, "Anthy: Failed to open anthy directory(%s).\n", dn);*/
+    errno = 0;
     r = anthy_mkdir_with_parents(dn, S_IRWXU);
     if (r == -1){
-      anthy_log(0, "Failed to create profile directory\n");
-      return ;
-    }
-    /*fprintf(stderr, "Anthy: Created\n");*/
-    r = chmod(dn, S_IRUSR | S_IWUSR | S_IXUSR);
-    if (r == -1) {
-      anthy_log(0, "But failed to change permission.\n");
+      anthy_log(0, "Failed to create profile directory: %s\n", strerror(errno));
+      return;
     }
   }
 }
@@ -238,12 +248,15 @@ copy_words_from_tt(struct seq_ent *seq, xstr *xs,
     tt_dic = old_anthy_private_tt_dic;
   else
     tt_dic = anthy_private_tt_dic;
-  if (!tt_dic) {
-    return ;
-  }
+  if (!tt_dic)
+    return;
   key = anthy_xstr_to_cstr(xs, encoding);
   key_len = strlen(key);
-  key_buf = malloc(key_len + 12);
+  if (!(key_buf = malloc(key_len + 12))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    free(key);
+    return;
+  }
   /* 辞書中には各単語が「見出し XXXX」(XXXXはランダムな文字列)を
    * キーとして保存されているので列挙する
    */
@@ -255,12 +268,19 @@ copy_words_from_tt(struct seq_ent *seq, xstr *xs,
       /* 「見出し 」で始まっていないので対象外 */
       break;
     }
-    /* 単語を読み出して登録 */
+    /* 単語を読み出して登録
+     * GCC 11.0.1 reports double-'free' of 'v'
+     * in case statement with "-Wanalyzer-double-free" option
+     * but 'v' is always allocated newly.
+     */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wanalyzer-double-free"
     v = anthy_trie_find(tt_dic, key_buf);
     if (v) {
       add_to_seq_ent(v, encoding, seq);
     }
     free(v);
+#pragma GCC diagnostic pop
     /**/
   } while (anthy_trie_find_next_key(tt_dic,
 				    key_buf, key_len + 8));
diff --git a/src-worddic/record.c b/src-worddic/record.c
index 5d71f88..edd487f 100644
--- a/src-worddic/record.c
+++ b/src-worddic/record.c
@@ -30,18 +30,20 @@
  * Copyright (C) 2000-2006 TABATA Yusuke
  * Copyright (C) 2000-2003 UGAWA Tomoharu
  * Copyright (C) 2001-2002 TAKAI Kosuke
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  */
 /*
  * パーソナリティ""は匿名パーソナリティであり，
  * ファイルへの読み書きは行わない．
  */
-#include <sys/types.h>
-#include <sys/stat.h>
+#include <assert.h>
 #include <errno.h>
-#include <unistd.h>
-#include <string.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
 
 #include "config.h"
 #include <anthy/anthy.h>
@@ -580,6 +582,7 @@ trie_remove(struct trie_root *root, xstr *key,
       r = s;
       s = trie_key_nth_bit(key, r->bit) ? r->r : r->l;
     }
+    assert(pp);
     *pp = (p->r == q) ? p->l : p->r;
     p->l = q->l;
     p->r = q->r;
@@ -1182,13 +1185,20 @@ read_journal_record(struct record_stat* rs)
     fclose(fp);
     return ;
   }
+  errno = 0;
   if (st.st_size < rs->last_update) {
 
     /* ファイルサイズが小さくなっているので、
      * 最初から読み込む */
-    fseek(fp, 0, SEEK_SET);
+    if (fseek(fp, 0, SEEK_SET)) {
+      anthy_log(0, "Failed fseek in %s:%d: %s\n",
+                __FILE__, __LINE__, anthy_strerror(errno));
+    }
   } else {
-    fseek(fp, rs->last_update, SEEK_SET);
+    if (fseek(fp, rs->last_update, SEEK_SET)) {
+      anthy_log(0, "Failed fseek in %s:%d: %s\n",
+                __FILE__, __LINE__, anthy_strerror(errno));
+    }
   }
   rs->journal_timestamp = st.st_mtime;
   while (!feof(fp)) {
@@ -2026,11 +2036,19 @@ setup_filenames(const char *id, struct record_stat *rst)
   /* 基本ファイル */
   rst->base_fn = (char*) malloc(base_len +
 				strlen("/last-record1_"));
+  if (!rst->base_fn) {
+      anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+      return;
+  }
   sprintf(rst->base_fn, "%s/last-record1_%s",
 	  home, id);
   /* 差分ファイル */
   rst->journal_fn = (char*) malloc(base_len +
 				   strlen("/last-record2_"));
+  if (!rst->journal_fn) {
+      anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+      return;
+  }
   sprintf(rst->journal_fn, "%s/last-record2_%s",
 	  home, id);
 }
diff --git a/src-worddic/textdict.c b/src-worddic/textdict.c
index ca5592a..7015664 100644
--- a/src-worddic/textdict.c
+++ b/src-worddic/textdict.c
@@ -1,5 +1,7 @@
 /*
  * ソートされたテキストから検索を行う
+ *
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  */
 /*
   This library is free software; you can redistribute it and/or
@@ -16,6 +18,8 @@
   License along with this library; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
  */
+#include <assert.h>
+#include <errno.h>
 #include <unistd.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -177,10 +181,12 @@ anthy_textdict_delete_line(struct textdict *td, int offset)
   }
   len = strlen(buf);
   fclose(fp);
-  update_mapping(td);
-  if (!td->mapping) {
+  if (update_mapping(td))
     return -1;
-  }
+  /* anthy_mmap() should make td->ptr if td->mapping is not null
+   * in update_mapping().
+   */
+  assert(td->ptr);
   size = anthy_mmap_size(td->mapping);
   memmove(&td->ptr[offset], &td->ptr[offset+len], size - offset - len);
   unmap(td);
@@ -188,7 +194,11 @@ anthy_textdict_delete_line(struct textdict *td, int offset)
     unlink(td->fn);
     return 0;
   }
-  truncate(td->fn, size - len);
+  errno = 0;
+  if (truncate(td->fn, size - len)) {
+    anthy_log(0, "Failed truncate in %s:%d: %s\n",
+              __FILE__, __LINE__, strerror(errno));
+  }
   return 0;
 }
 
@@ -198,13 +208,16 @@ anthy_textdict_insert_line(struct textdict *td, int offset,
 {
   int len = strlen(line);
   int size;
-  if (!td) {
+  if (!td)
     return -1;
-  }
-  if (expand_file(td, len)) {
+  if (expand_file(td, len))
     return -1;
-  }
-  update_mapping(td);
+  if (update_mapping(td))
+    return -1;
+  /* anthy_mmap() should make td->ptr if td->mapping is not null
+   * in update_mapping().
+   */
+  assert(td->ptr);
   size = anthy_mmap_size(td->mapping);
   memmove(&td->ptr[offset+len], &td->ptr[offset], size - offset - len);
   memcpy(&td->ptr[offset], line, len);
diff --git a/src-worddic/texttrie.c b/src-worddic/texttrie.c
index 9497a02..38576d8 100644
--- a/src-worddic/texttrie.c
+++ b/src-worddic/texttrie.c
@@ -31,7 +31,7 @@
  *  anthy_trie_print_array()
  *
  * Copyright (C) 2005-2006 TABATA Yusuke
- *
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1gmail.com>
  */
 /*
   This library is free software; you can redistribute it and/or
@@ -49,17 +49,20 @@
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
  */
 /* open & mmap */
-#include <unistd.h>
-#include <sys/types.h>
-#include <sys/stat.h>
 #include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
 /**/
+#include <assert.h>
+#include <ctype.h>
+#include <errno.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
-#include <ctype.h>
-#include <anthy/texttrie.h>
 #include <anthy/filemap.h>
+#include <anthy/texttrie.h>
+#include <anthy/logger.h>
 #include "dic_main.h"
 
 /* configs */
@@ -224,9 +227,10 @@ path_setup(struct path *path, const char *key, int len, int *buf)
   path->len = 0;
   path->cur = 0;
   /**/
-  while (*p) {
+  assert(p);
+  while ((*p) && (path->len < path->max_len)) {
     path->path[path->len] = p[0] * 256 + p[1];
-    path->len ++;
+    path->len++;
     p++;
     if (p[0]) {
       p++;
@@ -288,7 +292,7 @@ encode_super(struct cell *c, char *buf)
   buf += sput_int(buf, c->u.super.root_cell);
   buf += sput_int(buf, c->u.super.first_unused);
   buf += sput_int(buf, c->u.super.serial);
-  buf += sput_int(buf, LINE_LEN);
+  sput_int(buf, LINE_LEN);
 }
 
 static void
@@ -299,7 +303,7 @@ encode_node(struct cell *c, char *buf)
   buf += sput_int(buf, c->u.node.parent);
   buf += sput_int(buf, c->u.node.next);
   buf += sput_int(buf, c->u.node.child);
-  buf += sput_int(buf, c->u.node.body);
+  sput_int(buf, c->u.node.body);
 }
 
 static void
@@ -316,7 +320,7 @@ static void
 encode_unused(struct cell *c, char *buf)
 {
   buf += sprintf(buf, "-next=");
-  buf += sput_int(buf, c->u.next_unused);
+  sput_int(buf, c->u.next_unused);
 }
 
 static void
@@ -378,7 +382,11 @@ write_back_cell(struct text_trie *tt, struct cell *c, int idx)
   if (anthy_mmap_is_writable(tt->mapping)) {
     memcpy(&tt->ptr[idx*LINE_LEN], buf, LINE_LEN);
   } else {
-    fseek(tt->wfp, idx*LINE_LEN, SEEK_SET);
+    errno = 0;
+    if (fseek(tt->wfp, idx*LINE_LEN, SEEK_SET)) {
+      anthy_log(0, "Failed fseek in %s:%d: %s\n",
+                __FILE__, __LINE__, anthy_strerror(errno));
+    }
     fwrite(buf, LINE_LEN, 1, tt->wfp);
     fflush(tt->wfp);
   }
@@ -442,7 +450,7 @@ decode_super(struct cell *c, char *buf)
   buf = sget_int(buf, &c->u.super.size);
   buf = sget_int(buf, &c->u.super.root_cell);
   buf = sget_int(buf, &c->u.super.first_unused);
-  buf = sget_int(buf, &c->u.super.serial);
+  sget_int(buf, &c->u.super.serial);
   return 0;
 }
 
@@ -451,7 +459,7 @@ decode_unuse(struct cell *c, char *buf)
 {
   c->type = TT_UNUSED;
   buf = pass_str(buf, "-next=");
-  buf = sget_int(buf, &c->u.next_unused);
+  sget_int(buf, &c->u.next_unused);
   return 0;
 }
 
@@ -464,7 +472,7 @@ decode_node(struct cell *c, char *buf)
   buf = sget_int(buf, &c->u.node.parent);
   buf = sget_int(buf, &c->u.node.next);
   buf = sget_int(buf, &c->u.node.child);
-  buf = sget_int(buf, &c->u.node.body);
+  sget_int(buf, &c->u.node.body);
   return 0;
 }
 
@@ -507,6 +515,11 @@ decode_nth_cell(struct text_trie *tt, struct cell *c, int nth)
       (nth + 1)) {
     return NULL;
   }
+  /* GCC 11.0.1 reports dereference of NULL 'buf'
+   * in case statement with "-Wanalyzer-null-dereference" option.
+   */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wanalyzer-null-dereference"
   buf = &tt->ptr[nth*LINE_LEN];
 
   res = -1;
@@ -533,6 +546,7 @@ decode_nth_cell(struct text_trie *tt, struct cell *c, int nth)
     /*printf("decode fail (nth=%d::%s).\n", nth, buf);*/
     ;
   }
+#pragma GCC diagnostic pop
   if (res) {
     c->type = TT_UNUSED;
   }
@@ -606,7 +620,11 @@ set_file_size(struct text_trie *tt, int len)
     return 0;
   }
   if (cur_size > size) {
-    truncate(tt->fn, size);
+    errno = 0;
+    if (truncate(tt->fn, size)) {
+      anthy_log(0, "Failed truncate in %s:%d: %s\n",
+                __FILE__, __LINE__, strerror(errno));
+    }
   } else {
     err = expand_file(tt, (size - cur_size) / LINE_LEN);
     if (!err) {
@@ -817,7 +835,10 @@ static struct text_trie *
 alloc_tt(const char *fn, FILE *wfp)
 {
   struct text_trie *tt;
-  tt = malloc(sizeof(struct text_trie));
+  if (!(tt = malloc(sizeof(struct text_trie)))) {
+    anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+    return NULL;
+  }
   tt->fatal = 0;
   tt->wfp = wfp;
   tt->valid_super = 0;
@@ -1018,7 +1039,11 @@ trie_search_rec(struct text_trie *tt, struct path *p,
 		int parent_idx, int create)
 {
   int child_idx;
-  int key = p->path[p->cur];
+  int key;
+  assert(p);
+  assert(p->path);
+  assert((p->cur < p->max_len) && (p->cur >= 0));
+  key = p->path[p->cur];
   /* special case */
   if (p->cur == p->len) {
     return parent_idx;
@@ -1459,7 +1484,7 @@ disconnect(struct text_trie *tt, int parent_idx, int target_idx)
     /* not 1st child */
     int child_idx = parent_cell.u.node.child;
     while (child_idx) {
-      struct cell cur;
+      struct cell cur = { 0, };
       if (!decode_nth_cell(tt, &cur, child_idx)) {
 	return ;
       }
diff --git a/src-worddic/word_dic.c b/src-worddic/word_dic.c
index 70d9376..cc2cf89 100644
--- a/src-worddic/word_dic.c
+++ b/src-worddic/word_dic.c
@@ -5,7 +5,7 @@
  *
  * Copyright (C) 2000-2007 TABATA Yusuke
  * Copyright (C) 2005-2006 YOSHIDA Yuichi
- *
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  */
 /*
   This library is free software; you can redistribute it and/or
@@ -120,8 +120,17 @@ convert_vu(xstr *xs)
   }
   if (v > 0) {
     xstr *nx = malloc(sizeof(xstr));
+    if (!nx) {
+      anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+      return NULL;
+    }
     nx->len = xs->len + v;
     nx->str = malloc(sizeof(xchar)*nx->len);
+    if (!nx->str) {
+      anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+      free(nx);
+      return NULL;
+    }
     j = 0;
     /* 「ヴ」を「う゛」に変換しつつコピーする */
     for (i = 0; i < xs->len; i++) {
@@ -325,10 +334,17 @@ do_gang_load_dic(xstr *sentence, int is_reverse)
       nr += find_gang_elm(ator, &head, &xs);
     }
   }
-  array = malloc(sizeof(struct gang_elm *) * nr);
+  if (!(array = malloc(sizeof(struct gang_elm *) * nr))) {
+      anthy_log(0, "Failed malloc in %s:%d\n", __FILE__, __LINE__);
+      return;
+  }
   cur = head.tmp.next;
   for (i = 0; i < nr; i++) {
     array[i] = cur;
+    if (!cur) {
+      anthy_log(0, "gang_elm is null at %dth loop\n", i);
+      break;
+    }
     cur = cur->tmp.next;
   }
   qsort(array, nr, sizeof(struct gang_elm *), gang_elm_compare_func);
diff --git a/src-worddic/word_lookup.c b/src-worddic/word_lookup.c
index 79725e2..e0d53dc 100644
--- a/src-worddic/word_lookup.c
+++ b/src-worddic/word_lookup.c
@@ -14,7 +14,7 @@
  * Copyright (C) 2000-2007 TABATA Yusuke
  * Copyright (C) 2005-2006 YOSHIDA Yuichi
  * Copyright (C) 2001-2002 TAKAI Kosuke
- *
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  */
 /*
   This library is free software; you can redistribute it and/or
@@ -333,6 +333,7 @@ add_compound_ent(struct seq_ent *seq, struct wt_stat *ws,
 static void
 init_wt_stat(struct wt_stat *ws, char *line)
 {
+  memset(&ws->wt, 0, sizeof(wtype_t));
   ws->wt_name = NULL;
   ws->freq = 0;
   ws->feature = 0;
@@ -342,7 +343,7 @@ init_wt_stat(struct wt_stat *ws, char *line)
   ws->encoding = ANTHY_EUC_JP_ENCODING;
   if (*(ws->line) == 'u') {
     ws->encoding = ANTHY_UTF8_ENCODING;
-    ws->line ++;
+    ws->line++;
   }
 }
 
@@ -372,7 +373,7 @@ fill_dic_ent(char *line, struct seq_ent *seq,
       ws.offset += add_dic_ent(seq, &ws, yomi,
 			       is_reverse);
       if (ws.order_bonus > 0) {
-	ws.order_bonus --;
+	ws.order_bonus--;
       }
     }
     if (ws.line[ws.offset] == ' ') {
diff --git a/test/check.c b/test/check.c
index f67dbac..24163ca 100644
--- a/test/check.c
+++ b/test/check.c
@@ -1,6 +1,8 @@
 /* リリース前のチェックを行う */
+#include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <time.h>
 #include <anthy/anthy.h>
 #include <anthy/xstr.h>
 
@@ -48,7 +50,7 @@ test1(void)
 {
   anthy_context_t ac;
   char buf[100];
-  xstr *xs;
+  xstr *xs, *xs2;
   ac = anthy_create_context();
   if (!ac) {
     printf("failed to create context\n");
@@ -71,11 +73,29 @@ test1(void)
   }
   anthy_release_context(ac);
   xs = anthy_cstr_to_xstr("あいうえおがぎぐげご", ANTHY_UTF8_ENCODING);
-  xs = anthy_xstr_hira_to_half_kata(xs);
-  anthy_putxstrln(xs);
+  xs2 = anthy_xstr_hira_to_half_kata(xs);
+  anthy_putxstrln(xs2);
+  anthy_free_xstr(xs);
+  anthy_free_xstr(xs2);
   return 0;
 }
 
+/* compliant_rand:
+ * dont_call: "rand" should not be used for security-related applications,
+ * because linear congruential algorithms are too easy to break
+ * but we don't need the strict randoms here.
+ */
+static long int
+compliant_rand(void)
+{
+  struct timespec ts = { 0, };
+  if (!timespec_get (&ts, TIME_UTC)) {
+    printf("Failed timespec_get\n");
+    assert(0);
+  }
+  return ts.tv_nsec;
+}
+
 static int
 shake_test(const char *str)
 {
@@ -92,8 +112,8 @@ shake_test(const char *str)
     int nth, rsz;
     struct anthy_conv_stat cs;
     anthy_get_stat(ac, &cs);
-    nth = rand() % cs.nr_segment;
-    rsz = (rand() % 3) - 1;
+    nth = compliant_rand() % cs.nr_segment;
+    rsz = (compliant_rand() % 3) - 1;
     anthy_resize_segment(ac, nth, rsz);
   }
   anthy_release_context(ac);
diff --git a/test/main.c b/test/main.c
index 0c01755..6442257 100644
--- a/test/main.c
+++ b/test/main.c
@@ -16,6 +16,7 @@
  * Copyright (C) 2000-2006 TABATA Yusuke
  * Copyright (C) 2004-2006 YOSHIDA Yuichi
  * Copyright (C) 2001-2002 TAKAI Kosuke
+ * Copyright (C) 2021 Takao Fujiwara <takao.fujiwara1@gmail.com>
  *
  */
 
@@ -40,7 +41,7 @@
 
 /* テストデータとなる変換前の文字列 */
 #define TESTDATA "test.txt"
-const char *testdata = SRCDIR "/" TESTDATA;
+static char *testdata; /* = SRCDIR "/" TESTDATA */
 
 /* 変換後の文字列が妥当かどうかをチェックするためのデータ */
 #define EXPDATA "test.exp"
@@ -151,6 +152,7 @@ parse_args(struct condition *cond, int argc, char **argv)
 {
   int i;
   char *arg;
+  testdata = strdup(SRCDIR "/" TESTDATA);
   for (i = 1; i < argc; i++) {
     arg = argv[i];
     if (!strncmp(arg, "--", 2)) {
@@ -195,6 +197,7 @@ parse_args(struct condition *cond, int argc, char **argv)
       } else {
 	char *buf = alloca(strlen(SRCDIR)+strlen(arg) + 10);
 	sprintf(buf, SRCDIR "/%s.txt", arg);
+	free(testdata);
 	testdata = strdup(buf);
       }
     }
@@ -306,6 +309,7 @@ save_db(const char *fn, struct res_db *db)
   for (cr = db->res_list.next; cr; cr = cr->next) {
     dump_res(fp, cr);
   }
+  fclose(fp);
 }
 
 static void
@@ -316,7 +320,8 @@ ask_results(struct res_db *db)
     if (cr->check == CHK_UNKNOWN && cr->used == 1) {
       char buf[256];
       printf("%s -> %s (y/n/d/q)\n", cr->src_str, cr->res_str);
-      fgets(buf, 256, stdin);
+      if (!fgets(buf, 256, stdin))
+        printf("Failed fgets in %s:%d\n", __FILE__, __LINE__);
       if (buf[0] == 'y') {
 	cr->check = CHK_OK;
       } else if (buf[0] == 'n') {
@@ -376,7 +381,7 @@ main(int argc,char **argv)
   int line = 1;
 
   cur_input.serial = 0;
-  cur_input.str = 0;
+  cur_input.str = NULL;
   init_condition(&cond);
 
   parse_args(&cond, argc, argv);
@@ -392,6 +397,7 @@ main(int argc,char **argv)
     printf("failed to open %s.\n", testdata);
     return 0;
   }
+  free(testdata);
   
   ac = init_lib(cond.use_utf8);
 
@@ -408,6 +414,9 @@ main(int argc,char **argv)
     }
     line++;
   }
+  fclose(fp);
+  free(cur_input.str);
+  cur_input.str = NULL;
 
   anthy_release_context(ac);
   anthy_quit();
diff --git a/test/test-matrix.c b/test/test-matrix.c
index 0bb9917..13edcc2 100644
--- a/test/test-matrix.c
+++ b/test/test-matrix.c
@@ -1,4 +1,5 @@
 /* 疎行列のテスト用コード */
+#include <stdlib.h>
 #include <stdio.h>
 #include <anthy/dic.h>
 #include <anthy/diclib.h>
@@ -26,6 +27,9 @@ zero_matrix(void)
   im = mi->image;
   e = anthy_matrix_image_peek(im, 0, 0);
   printf("zero matrix: size=%d (0,0)=%d\n", mi->size, e);
+  free(mi->image);
+  free(mi);
+  anthy_sparse_matrix_free(m);
 }
 
 static void
@@ -61,6 +65,9 @@ dense_matrix(void)
     }
   }
   printf("%d errors in desnse matrix\n", fail);
+  free(mi->image);
+  free(mi);
+  anthy_sparse_matrix_free(m);
 }
 
 int
-- 
2.28.0

From 255323305b3621286cc4025ac59fa7d37fa1e7ce Mon Sep 17 00:00:00 2001
From: fujiwarat <takao.fujiwara1@gmail.com>
Date: Fri, 6 May 2022 20:33:47 +0900
Subject: [PATCH] src-main/context.c: Code reviews

---
 src-main/context.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/src-main/context.c b/src-main/context.c
index 20dde71..d84858c 100644
--- a/src-main/context.c
+++ b/src-main/context.c
@@ -451,7 +451,7 @@ anthy_get_nth_segment(struct segment_list *sl, int n)
       n < 0) {
     return NULL;
   }
-  for (i = 0, se = sl->list_head.next; i < n; i++, se = se->next);
+  for (i = 0, se = sl->list_head.next; (i < n) && se; i++, se = se->next);
   return se;
 }
 
@@ -499,6 +499,17 @@ get_change_state(struct anthy_context *ac)
   int i;
   for (i = 0; i < ac->seg_list.nr_segments; i++) {
     struct seg_ent *s = anthy_get_nth_segment(&ac->seg_list, i);
+    if (!ac->split_info.ce) {
+      anthy_log(0, "ac->split_info.ce is NULL %s:%d\n", __FILE__, __LINE__);
+      resize = 1;
+      break;
+    }
+    if (!s) {
+      anthy_log(0, "ac->seg_list %dth entry is NULL %s:%d\n",
+                i, __FILE__, __LINE__);
+      resize = 1;
+      continue;
+    }
     if (ac->split_info.ce[s->from].initial_seg_len != s->len) {
       resize = 1;
     }
@@ -538,6 +549,11 @@ write_history(int                   fd,
     struct seg_ent *s = anthy_get_nth_segment(&ac->seg_list, i);
     char *c;
     /**/
+    if (!s) {
+      anthy_log(0, "ac->seg_list %dth entry is NULL %s:%d\n",
+                i, __FILE__, __LINE__);
+      continue;
+    }
     if (s->committed < 0) {
       dprintf(fd, "?|");
       continue ;
@@ -647,9 +663,11 @@ print_segment(struct seg_ent *e)
 {
   int i;
 
+  assert(e);
   anthy_putxstr(&e->str);
   printf("(");
   for ( i = 0 ; i < e->nr_cands ; i++) {
+    assert(e->cands);
     anthy_print_candidate(e->cands[i]);
     printf(",");
   }
-- 
2.35.1