Bug #25097 mysql_server_init fails silently if no errmsg.sys is present.

There was no way to return an error from the client library
if no MYSQL connections was established.
So here i added variables to store that king of errors and
made functions like mysql_error(NULL) to return these.


client/mysql.cc:
  Bug #25097 mysql_server_init fails silently if no errmsg.sys is present.
  
  Show the error message on std_error
include/sql_common.h:
  Bug #25097 mysql_server_init fails silently if no errmsg.sys is present.
  
  cant_connect_sqlstate constant declared
libmysql/libmysql.c:
  Bug #25097 mysql_server_init fails silently if no errmsg.sys is present.
  
  mysql_sqlstate(NULL) returns 'unknown_sqlstate'
libmysqld/lib_sql.cc:
  Bug #25097 mysql_server_init fails silently if no errmsg.sys is present.
  
  EMBEDDED_SERVER version of the vprint_msg_to_log() implemented
sql-common/client.c:
  Bug #25097 mysql_server_init fails silently if no errmsg.sys is present.
  
  mysql_server_last_errno and mysql_server_last_error introduced
  to store errors not related to particular connections.
  
  mysql_error(NULL) and mysql_errno(NULL) now returns these
  mysql_server_last_error and errno respectively
sql/log.cc:
  Bug #25097 mysql_server_init fails silently if no errmsg.sys is present.
  
  EMBEDDED_LIBRARY implementation of the vprint_msg_to_log() moved
  to lib_sql.cc

client/mysql.cc

@@ -420,6 +420,7 @@ int main(int argc,char *argv[])
   }
   if (mysql_server_init(emb_argc, emb_argv, (char**) server_default_groups))
   {
+    put_error(NULL);
     free_defaults(defaults_argv);
     my_end(0);
     exit(1);

include/sql_common.h

@@ -15,6 +15,7 @@
 
 
 extern const char	*unknown_sqlstate;
+extern const char	*cant_connect_sqlstate;
 extern const char	*not_error_sqlstate;
 
 #ifdef	__cplusplus

libmysql/libmysql.c

@@ -1486,7 +1486,7 @@ my_ulonglong STDCALL mysql_insert_id(MYSQL *mysql)
 
 const char *STDCALL mysql_sqlstate(MYSQL *mysql)
 {
-  return mysql->net.sqlstate;
+  return mysql ? mysql->net.sqlstate : cant_connect_sqlstate;
 }
 
 uint STDCALL mysql_warning_count(MYSQL *mysql)

libmysqld/lib_sql.cc

@@ -47,6 +47,8 @@ C_MODE_START
 #include <sql_common.h>
 #include "embedded_priv.h"
 
+extern unsigned int mysql_server_last_errno;
+extern char mysql_server_last_error[MYSQL_ERRMSG_SIZE];
 static my_bool emb_read_query_result(MYSQL *mysql);
 
 
@@ -1084,3 +1086,11 @@ bool Protocol::net_store_data(const char *from, uint length)
   return false;
 }
 
+
+void vprint_msg_to_log(enum loglevel level __attribute__((unused)),
+                       const char *format, va_list argsi)
+{
+  vsnprintf(mysql_server_last_error, sizeof(mysql_server_last_error),
+           format, argsi);
+  mysql_server_last_errno= CR_UNKNOWN_ERROR;
+}

sql-common/client.c

@@ -117,6 +117,7 @@ uint		mysql_port=0;
 char		*mysql_unix_port= 0;
 const char	*unknown_sqlstate= "HY000";
 const char	*not_error_sqlstate= "00000";
+const char	*cant_connect_sqlstate= "08001";
 #ifdef HAVE_SMEM
 char		 *shared_memory_base_name= 0;
 const char 	*def_shared_memory_base_name= default_shared_memory_base_name;
@@ -131,6 +132,9 @@ static int wait_for_data(my_socket fd, uint timeout);
 
 CHARSET_INFO *default_client_charset_info = &my_charset_latin1;
 
+/* Server error code and message */
+unsigned int mysql_server_last_errno;
+char mysql_server_last_error[MYSQL_ERRMSG_SIZE];
 
 /****************************************************************************
   A modified version of connect().  my_connect() allows you to specify
@@ -752,10 +756,18 @@ void set_mysql_error(MYSQL *mysql, int errcode, const char *sqlstate)
   DBUG_PRINT("enter", ("error :%d '%s'", errcode, ER(errcode)));
   DBUG_ASSERT(mysql != 0);
 
-  net= &mysql->net;
-  net->last_errno= errcode;
-  strmov(net->last_error, ER(errcode));
-  strmov(net->sqlstate, sqlstate);
+  if (mysql)
+  {
+    net= &mysql->net;
+    net->last_errno= errcode;
+    strmov(net->last_error, ER(errcode));
+    strmov(net->sqlstate, sqlstate);
+  }
+  else
+  {
+    mysql_server_last_errno= errcode;
+    strmov(mysql_server_last_error, ER(errcode));
+  }
 
   DBUG_VOID_RETURN;
 }
@@ -1477,7 +1489,10 @@ mysql_init(MYSQL *mysql)
   if (!mysql)
   {
     if (!(mysql=(MYSQL*) my_malloc(sizeof(*mysql),MYF(MY_WME | MY_ZEROFILL))))
+    {
+      set_mysql_error(NULL, CR_OUT_OF_MEMORY, unknown_sqlstate);
       return 0;
+    }
     mysql->free_me=1;
   }
   else
@@ -3064,13 +3079,13 @@ unsigned int STDCALL mysql_num_fields(MYSQL_RES *res)
 
 uint STDCALL mysql_errno(MYSQL *mysql)
 {
-  return mysql->net.last_errno;
+  return mysql ? mysql->net.last_errno : mysql_server_last_errno;
 }
 
 
 const char * STDCALL mysql_error(MYSQL *mysql)
 {
-  return mysql->net.last_error;
+  return mysql ? mysql->net.last_error : mysql_server_last_error;
 }
 
 

sql/log.cc

@@ -2454,12 +2454,7 @@ static void print_buffer_to_nt_eventlog(enum loglevel level, char *buff,
     void
 */
 
-#ifdef EMBEDDED_LIBRARY
-void vprint_msg_to_log(enum loglevel level __attribute__((unused)),
-                       const char *format __attribute__((unused)),
-                       va_list argsi __attribute__((unused)))
-{}
-#else /*!EMBEDDED_LIBRARY*/
+#ifndef EMBEDDED_LIBRARY
 static void print_buffer_to_file(enum loglevel level, const char *buffer)
 {
   time_t skr;