WIP MDEV-22387bb-10.5-MDEV-22387

25 files changed, 94 insertions, 54 deletions

diff --git a/client/completion_hash.cc b/client/completion_hash.cc
index 0bfb4e879e4..0a13b79084f 100644
--- a/client/completion_hash.cc
+++ b/client/completion_hash.cc
@@ -205,7 +205,8 @@ Bucket *find_longest_match(HashTable *ht, char *str, uint length,
 void completion_hash_clean(HashTable *ht)
 {
   free_root(&ht->mem_root,MYF(0));
-  bzero((char*) ht->arBuckets,ht->nTableSize*sizeof(Bucket *));
+  if (size_t s= ht->nTableSize)
+    bzero((char*) ht->arBuckets, s * sizeof(Bucket *));
 }
 
 
diff --git a/include/my_sys.h b/include/my_sys.h
index a66bfd8217c..59d88f193c6 100644
--- a/include/my_sys.h
+++ b/include/my_sys.h
@@ -511,8 +511,11 @@ static inline int my_b_write(IO_CACHE *info, const uchar *Buffer, size_t Count)
   MEM_CHECK_DEFINED(Buffer, Count);
   if (info->write_pos + Count <= info->write_end)
   {
-    memcpy(info->write_pos, Buffer, Count);
-    info->write_pos+= Count;
+    if (Count)
+    {
+      memcpy(info->write_pos, Buffer, Count);
+      info->write_pos+= Count;
+    }
     return 0;
   }
   return _my_b_write(info, Buffer, Count);
diff --git a/libmariadb b/libmariadb
-Subproject 62427520a5ba20e42fe51f5045062a7a9cadb46
+Subproject e38244220646a7e95c9be22576460aa7a4eb715
diff --git a/mysys/array.c b/mysys/array.c
index 1d1d9dd1c64..59698a4cc7c 100644
--- a/mysys/array.c
+++ b/mysys/array.c
@@ -140,8 +140,9 @@ void *alloc_dynamic(DYNAMIC_ARRAY *array)
                                         array->size_of_element,
                                         MYF(array->malloc_flags | MY_WME))))
         DBUG_RETURN(0);
-      memcpy(new_ptr, array->buffer,
-             array->elements * array->size_of_element);
+      if (array->elements)
+        memcpy(new_ptr, array->buffer,
+               array->elements * array->size_of_element);
       array->malloc_flags&= ~MY_INIT_BUFFER_USED;
     }
     else if (!(new_ptr=(char*)
diff --git a/mysys/my_alloc.c b/mysys/my_alloc.c
index d7e62726b22..edcb4ce7483 100644
--- a/mysys/my_alloc.c
+++ b/mysys/my_alloc.c
@@ -477,7 +477,7 @@ char *strmake_root(MEM_ROOT *root, const char *str, size_t len)
 void *memdup_root(MEM_ROOT *root, const void *str, size_t len)
 {
   char *pos;
-  if ((pos=alloc_root(root,len)))
+  if ((pos=alloc_root(root,len)) && len)
     memcpy(pos,str,len);
   return pos;
 }
diff --git a/plugin/server_audit/server_audit.c b/plugin/server_audit/server_audit.c
index bd630a16eb7..87f53b1db87 100644
--- a/plugin/server_audit/server_audit.c
+++ b/plugin/server_audit/server_audit.c
@@ -709,6 +709,8 @@ static char *coll_search(struct user_coll *c, const char *n, size_t len)
 {
   struct user_name un;
   struct user_name *found;
+  if (!c->n_users)
+    return 0;
   un.name_len= len;
   un.name= (char *) n;
   found= (struct user_name*)  bsearch(&un, c->users, c->n_users,
@@ -739,7 +741,8 @@ static int coll_insert(struct user_coll *c, char *n, size_t len)
 
 static void coll_sort(struct user_coll *c)
 {
-  qsort(c->users, c->n_users, sizeof(c->users[0]), cmp_users);
+  if (c->n_users)
+    qsort(c->users, c->n_users, sizeof(c->users[0]), cmp_users);
 }
 
 
@@ -970,7 +973,8 @@ static void get_str_n(char *dest, int *dest_len, size_t dest_size,
   if (src_len >= dest_size)
     src_len= dest_size - 1;
 
-  memcpy(dest, src, src_len);
+  if (src_len)
+    memcpy(dest, src, src_len);
   dest[src_len]= 0;
   *dest_len= (int)src_len;
 }
diff --git a/sql/field.cc b/sql/field.cc
index f8d9cbf93ce..fe3aebce05d 100644
--- a/sql/field.cc
+++ b/sql/field.cc
@@ -8724,7 +8724,10 @@ int Field_blob::cmp_binary(const uchar *a_ptr, const uchar *b_ptr,
   b_length=get_length(b_ptr);
   if (b_length > max_length)
     b_length=max_length;
-  diff=memcmp(a,b,MY_MIN(a_length,b_length));
+  if (uint32 len= MY_MIN(a_length,b_length))
+    diff= memcmp(a,b,len);
+  else
+    diff= 0;
   return diff ? diff : (int) (a_length - b_length);
 }
 
@@ -8751,7 +8754,8 @@ uint Field_blob::get_key_image_itRAW(const uchar *ptr_arg, uchar *buff,
     length=(uint) blob_length;
   }
   int2store(buff,length);
-  memcpy(buff+HA_KEY_BLOB_LENGTH, blob, length);
+  if (length)
+    memcpy(buff+HA_KEY_BLOB_LENGTH, blob, length);
   return HA_KEY_BLOB_LENGTH+length;
 }
 
diff --git a/sql/handler.h b/sql/handler.h
index e06b6a7aa43..41da458aa2a 100644
--- a/sql/handler.h
+++ b/sql/handler.h
@@ -866,8 +866,10 @@ struct xid_t {
   void set(long f, const char *g, long gl, const char *b, long bl)
   {
     formatID= f;
-    memcpy(data, g, gtrid_length= gl);
-    memcpy(data+gl, b, bqual_length= bl);
+    if ((gtrid_length= gl))
+      memcpy(data, g, gl);
+    if ((bqual_length= bl))
+      memcpy(data+gl, b, bl);
   }
   void set(ulonglong xid)
   {
diff --git a/sql/item_func.cc b/sql/item_func.cc
index c0714bc263f..0aeb763ea82 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -4894,7 +4894,8 @@ update_hash(user_var_entry *entry, bool set_null, void *ptr, size_t length,
       length--;					// Fix length change above
       entry->value[length]= 0;			// Store end \0
     }
-    memmove(entry->value, ptr, length);
+    if (length)
+      memmove(entry->value, ptr, length);
     if (type == DECIMAL_RESULT)
       ((my_decimal*)entry->value)->fix_buffer_pointer();
     entry->length= length;
diff --git a/sql/item_sum.cc b/sql/item_sum.cc
index 4a94169c6f8..5d0578df4ac 100644
--- a/sql/item_sum.cc
+++ b/sql/item_sum.cc
@@ -1,5 +1,5 @@
 /* Copyright (c) 2000, 2015, Oracle and/or its affiliates.
-   Copyright (c) 2008, 2015, MariaDB
+   Copyright (c) 2008, 2020, MariaDB
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -473,7 +473,8 @@ Item_sum::Item_sum(THD *thd, Item_sum *item):
     if (!(orig_args= (Item**) thd->alloc(sizeof(Item*)*arg_count)))
       return;
   }
-  memcpy(orig_args, item->orig_args, sizeof(Item*)*arg_count);
+  if (arg_count)
+    memcpy(orig_args, item->orig_args, sizeof(Item*)*arg_count);
   init_aggregator();
   with_distinct= item->with_distinct;
   if (item->aggr)
@@ -1132,7 +1133,8 @@ Item_sum_num::fix_fields(THD *thd, Item **ref)
       check_sum_func(thd, ref))
     return TRUE;
 
-  memcpy (orig_args, args, sizeof (Item *) * arg_count);
+  if (arg_count)
+    memcpy (orig_args, args, sizeof (Item *) * arg_count);
   fixed= 1;
   return FALSE;
 }
@@ -1365,7 +1367,8 @@ Item_sum_sp::fix_fields(THD *thd, Item **ref)
   if (check_sum_func(thd, ref))
     return TRUE;
 
-  memcpy(orig_args, args, sizeof(Item *) * arg_count);
+  if (arg_count)
+    memcpy(orig_args, args, sizeof(Item *) * arg_count);
   fixed= 1;
   return FALSE;
 }
@@ -3928,7 +3931,8 @@ Item_func_group_concat(THD *thd, Name_resolution_context *context_arg,
 
   /* orig_args is only used for print() */
   orig_args= (Item**) (order + arg_count_order);
-  memcpy(orig_args, args, sizeof(Item*) * arg_count);
+  if (arg_count)
+    memcpy(orig_args, args, sizeof(Item*) * arg_count);
   if (limit_clause)
   {
     row_limit= row_limit_arg;
diff --git a/sql/lex_string.h b/sql/lex_string.h
index 008e5f75812..4fa92dc3565 100644
--- a/sql/lex_string.h
+++ b/sql/lex_string.h
@@ -81,7 +81,7 @@ static inline bool cmp(const LEX_CSTRING *a, const LEX_CSTRING *b)
 }
 static inline bool cmp(const LEX_CSTRING a, const LEX_CSTRING b)
 {
-  return a.length != b.length || memcmp(a.str, b.str, a.length);
+  return a.length != b.length || (a.length && memcmp(a.str, b.str, a.length));
 }
 
 /*
diff --git a/sql/mf_iocache_encr.cc b/sql/mf_iocache_encr.cc
index 072c0a48269..63830ec620a 100644
--- a/sql/mf_iocache_encr.cc
+++ b/sql/mf_iocache_encr.cc
@@ -1,5 +1,5 @@
 /*
-   Copyright (c) 2015, MariaDB
+   Copyright (c) 2015, 2020, MariaDB
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -85,7 +85,6 @@ static int my_b_encr_read(IO_CACHE *info, uchar *Buffer, size_t Count)
 
   do
   {
-    size_t copied;
     uint elength, wlength, length;
     uchar iv[MY_AES_BLOCK_SIZE]= {0};
 
@@ -116,11 +115,13 @@ static int my_b_encr_read(IO_CACHE *info, uchar *Buffer, size_t Count)
 
     DBUG_ASSERT(length <= info->buffer_length);
 
-    copied= MY_MIN(Count, (size_t)(length - pos_offset));
-
-    memcpy(Buffer, info->buffer + pos_offset, copied);
-    Count-= copied;
-    Buffer+= copied;
+    size_t copied= MY_MIN(Count, (size_t)(length - pos_offset));
+    if (copied)
+    {
+      memcpy(Buffer, info->buffer + pos_offset, copied);
+      Count-= copied;
+      Buffer+= copied;
+    }
 
     info->read_pos= info->buffer + pos_offset + copied;
     info->read_end= info->buffer + length;
diff --git a/sql/opt_split.cc b/sql/opt_split.cc
index a6031f75a5b..3a086aef04c 100644
--- a/sql/opt_split.cc
+++ b/sql/opt_split.cc
@@ -1,5 +1,5 @@
 /*
-   Copyright (c) 2017 MariaDB
+   Copyright (c) 2017, 2020, MariaDB
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -749,13 +749,13 @@ void JOIN::add_keyuses_for_splitting()
   if (allocate_dynamic(&keyuse, save_qep->keyuse.elements + added_keyuse_count))
     goto err;
 
-  memcpy(keyuse.buffer,
-         save_qep->keyuse.buffer,
-         (size_t) save_qep->keyuse.elements * keyuse.size_of_element);
-  keyuse.elements= save_qep->keyuse.elements;
+  idx= keyuse.elements= save_qep->keyuse.elements;
+  if (keyuse.elements)
+    memcpy(keyuse.buffer,
+           save_qep->keyuse.buffer,
+           (size_t) keyuse.elements * keyuse.size_of_element);
 
   keyuse_ext= &ext_keyuses_for_splitting->at(0);
-  idx= save_qep->keyuse.elements;
   for (i=0; i < added_keyuse_count; i++, keyuse_ext++, idx++)
   {
     set_dynamic(&keyuse, (KEYUSE *) keyuse_ext, idx);
diff --git a/sql/sql_class.cc b/sql/sql_class.cc
index 6011dbbc6dd..a4fd26cf7d8 100644
--- a/sql/sql_class.cc
+++ b/sql/sql_class.cc
@@ -4982,7 +4982,8 @@ extern "C" size_t thd_query_safe(MYSQL_THD thd, char *buf, size_t buflen)
   if (!mysql_mutex_trylock(&thd->LOCK_thd_data))
   {
     len= MY_MIN(buflen - 1, thd->query_length());
-    memcpy(buf, thd->query(), len);
+    if (len)
+      memcpy(buf, thd->query(), len);
     mysql_mutex_unlock(&thd->LOCK_thd_data);
   }
   buf[len]= '\0';
diff --git a/sql/sql_join_cache.cc b/sql/sql_join_cache.cc
index 5a243cd0a6d..4b879293fdb 100644
--- a/sql/sql_join_cache.cc
+++ b/sql/sql_join_cache.cc
@@ -1397,7 +1397,8 @@ uint JOIN_CACHE::write_record_data(uchar * link, bool *is_full)
 	blob_field->get_image(cp, copy->length, 
 			      blob_field->charset());
         DBUG_ASSERT(cp + copy->length + copy->blob_length <= buff + buff_size);
-	memcpy(cp+copy->length, copy->str, copy->blob_length);               
+        if (copy->blob_length)
+          memcpy(cp+copy->length, copy->str, copy->blob_length);
 	cp+= copy->length+copy->blob_length;
       }
       break;
diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc
index 61e3b89c9a3..60a7a4f6ce0 100644
--- a/sql/sql_lex.cc
+++ b/sql/sql_lex.cc
@@ -10209,7 +10209,8 @@ bool LEX::new_sp_instr_stmt(THD *thd,
   qbuff.length= prefix.length + suffix.length;
   if (!(qbuff.str= (char*) alloc_root(thd->mem_root, qbuff.length + 1)))
     return true;
-  memcpy(qbuff.str, prefix.str, prefix.length);
+  if (prefix.length)
+    memcpy(qbuff.str, prefix.str, prefix.length);
   strmake(qbuff.str + prefix.length, suffix.str, suffix.length);
   i->m_query= qbuff;
   return sphead->add_instr(i);
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 2a856a0d51f..6071fe10929 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -27984,10 +27984,10 @@ JOIN::reoptimize(Item *added_where, table_map join_tables,
   if (save_to)
   {
     DBUG_ASSERT(!keyuse.elements);
-    memcpy(keyuse.buffer,
-           save_to->keyuse.buffer,
-           (size_t) save_to->keyuse.elements * keyuse.size_of_element);
     keyuse.elements= save_to->keyuse.elements;
+    if (size_t e= keyuse.elements)
+      memcpy(keyuse.buffer,
+             save_to->keyuse.buffer, e * keyuse.size_of_element);
   }
 
   /* Add the new access methods to the keyuse array. */
diff --git a/sql/sql_string.cc b/sql/sql_string.cc
index 94f2e6fc8c6..d1998e6d420 100644
--- a/sql/sql_string.cc
+++ b/sql/sql_string.cc
@@ -237,8 +237,8 @@ bool Binary_string::copy(const Binary_string &str)
 {
   if (alloc(str.str_length))
     return TRUE;
-  str_length=str.str_length;
-  bmove(Ptr,str.Ptr,str_length);		// May be overlapping
+  if ((str_length=str.str_length))
+    bmove(Ptr,str.Ptr,str_length);		// May be overlapping
   Ptr[str_length]=0;
   return FALSE;
 }
diff --git a/sql/table.h b/sql/table.h
index ec865f2e3ce..83e8b69b5e3 100644
--- a/sql/table.h
+++ b/sql/table.h
@@ -3194,7 +3194,8 @@ inline void mark_as_null_row(TABLE *table)
 {
   table->null_row=1;
   table->status|=STATUS_NULL_ROW;
-  bfill(table->null_flags,table->s->null_bytes,255);
+  if (table->s->null_bytes)
+    bfill(table->null_flags,table->s->null_bytes,255);
 }
 
 bool is_simple_order(ORDER *order);
diff --git a/sql/unireg.cc b/sql/unireg.cc
index c299549843f..ecd5bb8d430 100644
--- a/sql/unireg.cc
+++ b/sql/unireg.cc
@@ -1104,8 +1104,11 @@ static bool pack_fields(uchar **buff_arg, List<Create_field> &create_fields,
     it.rewind();
     while ((field=it++))
     {
-      memcpy(buff, field->comment.str, field->comment.length);
-      buff+= field->comment.length;
+      if (size_t l= field->comment.length)
+      {
+        memcpy(buff, field->comment.str, l);
+        buff+= l;
+      }
     }
   }
   *buff_arg= buff;
diff --git a/sql/unireg.h b/sql/unireg.h
index 873d6f681fc..dbff9ff77f8 100644
--- a/sql/unireg.h
+++ b/sql/unireg.h
@@ -76,7 +76,8 @@
 #define cmp_record(A,B) memcmp((A)->record[0],(A)->B,(size_t) (A)->s->reclength)
 #define empty_record(A) { \
                           restore_record((A),s->default_values); \
-                          bfill((A)->null_flags,(A)->s->null_bytes,255);\
+                          if ((A)->s->null_bytes) \
+                            bfill((A)->null_flags,(A)->s->null_bytes,255); \
                         }
 
 	/* Defines for use with openfrm, openprt and openfrd */
diff --git a/storage/myisam/mi_key.c b/storage/myisam/mi_key.c
index ed72acf627e..087eb59c7c0 100644
--- a/storage/myisam/mi_key.c
+++ b/storage/myisam/mi_key.c
@@ -147,8 +147,11 @@ uint _mi_make_key(register MI_INFO *info, uint keynr, uchar *key,
       set_if_smaller(length,tmp_length);
       FIX_LENGTH(cs, pos, length, char_length);
       store_key_length_inc(key,char_length);
-      memcpy(key, pos, char_length);
-      key+= char_length;
+      if (char_length)
+      {
+        memcpy(key, pos, char_length);
+        key+= char_length;
+      }
       continue;
     }
     else if (keyseg->flag & HA_SWAP_KEY)
diff --git a/storage/perfschema/pfs_setup_object.cc b/storage/perfschema/pfs_setup_object.cc
index 9325b84997f..47afd130761 100644
--- a/storage/perfschema/pfs_setup_object.cc
+++ b/storage/perfschema/pfs_setup_object.cc
@@ -126,12 +126,18 @@ static void set_setup_object_key(PFS_setup_object_key *key,
   char *ptr= &key->m_hash_key[0];
   ptr[0]= (char) object_type;
   ptr++;
-  memcpy(ptr, schema, schema_length);
-  ptr+= schema_length;
+  if (schema_length)
+  {
+    memcpy(ptr, schema, schema_length);
+    ptr+= schema_length;
+  }
   ptr[0]= 0;
   ptr++;
-  memcpy(ptr, object, object_length);
-  ptr+= object_length;
+  if (object_length)
+  {
+    memcpy(ptr, object, object_length);
+    ptr+= object_length;
+  }
   ptr[0]= 0;
   ptr++;
   key->m_key_length= (uint)(ptr - &key->m_hash_key[0]);
diff --git a/strings/ctype-bin.c b/strings/ctype-bin.c
index 84e5c85697b..c11be2e5926 100644
--- a/strings/ctype-bin.c
+++ b/strings/ctype-bin.c
@@ -1,6 +1,6 @@
 /* Copyright (c) 2002-2007 MySQL AB & tommy@valley.ne.jp
    Copyright (c) 2002, 2014, Oracle and/or its affiliates.
-   Copyright (c) 2009, 2014, SkySQL Ab.
+   Copyright (c) 2009, 2020, MariaDB Corporation.
    
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
@@ -401,7 +401,7 @@ my_strnxfrm_8bit_bin(CHARSET_INFO *cs,
 {
   set_if_smaller(srclen, dstlen);
   set_if_smaller(srclen, nweights);
-  if (dst != src)
+  if (srclen && dst != src)
     memcpy(dst, src, srclen);
   return my_strxfrm_pad_desc_and_reverse(cs, dst, dst + srclen, dst + dstlen,
                                          (uint)(nweights - srclen), flags, 0);
diff --git a/strings/ctype-tis620.c b/strings/ctype-tis620.c
index 90773a0dabc..1a5dd6dbfde 100644
--- a/strings/ctype-tis620.c
+++ b/strings/ctype-tis620.c
@@ -555,9 +555,11 @@ int my_strnncollsp_tis620(CHARSET_INFO * cs __attribute__((unused)),
     alloced= a= (uchar*) my_malloc(PSI_INSTRUMENT_ME, a_length+b_length+2, MYF(MY_FAE));
   
   b= a + a_length+1;
-  memcpy((char*) a, (char*) a0, a_length);
+  if (a_length)
+    memcpy((char*) a, (char*) a0, a_length);
   a[a_length]= 0;	/* if length(a0)> len1, need to put 'end of string' */
-  memcpy((char *)b, (char *)b0, b_length);
+  if (b_length)
+    memcpy((char *)b, (char *)b0, b_length);
   b[b_length]= 0;	/* put end of string */
   a_length= thai2sortable(a, a_length);
   b_length= thai2sortable(b, b_length);