MDEV-34494 Add server_uid global variable and add it to error log at startup

The feedback plugin server_uid variable and the calculate_server_uid()
function is moved from feedback/utils.cc to sql/mysqld.cc

server_uid is added as a global variable (shown in 'show variables') and
is written to the error log on server startup together with server version
and server commit id.

mysql-test/main/mysqld--help.test

@@ -27,7 +27,7 @@ perl;
                large-files-support lower-case-file-system system-time-zone
                collation-server character-set-server log-tc-size table-cache
                table-open-cache table-open-cache-instances max-connections
-               tls-version version.*/;
+               server-uid tls-version version.*/;
 
   # Plugins which may or may not be there:
   @plugins=qw/innodb archive blackhole federated partition s3

mysql-test/suite/sys_vars/r/sysvars_server_embedded.result

@@ -3072,6 +3072,16 @@ NUMERIC_BLOCK_SIZE	1
 ENUM_VALUE_LIST	NULL
 READ_ONLY	NO
 COMMAND_LINE_ARGUMENT	REQUIRED
+VARIABLE_NAME	SERVER_UID
+VARIABLE_SCOPE	GLOBAL
+VARIABLE_TYPE	VARCHAR
+VARIABLE_COMMENT	Automatically calculated server unique id hash
+NUMERIC_MIN_VALUE	NULL
+NUMERIC_MAX_VALUE	NULL
+NUMERIC_BLOCK_SIZE	NULL
+ENUM_VALUE_LIST	NULL
+READ_ONLY	YES
+COMMAND_LINE_ARGUMENT	NULL
 VARIABLE_NAME	SKIP_EXTERNAL_LOCKING
 VARIABLE_SCOPE	GLOBAL
 VARIABLE_TYPE	BOOLEAN

mysql-test/suite/sys_vars/r/sysvars_server_notembedded.result

@@ -3522,6 +3522,16 @@ NUMERIC_BLOCK_SIZE	1
 ENUM_VALUE_LIST	NULL
 READ_ONLY	NO
 COMMAND_LINE_ARGUMENT	REQUIRED
+VARIABLE_NAME	SERVER_UID
+VARIABLE_SCOPE	GLOBAL
+VARIABLE_TYPE	VARCHAR
+VARIABLE_COMMENT	Automatically calculated server unique id hash
+NUMERIC_MIN_VALUE	NULL
+NUMERIC_MAX_VALUE	NULL
+NUMERIC_BLOCK_SIZE	NULL
+ENUM_VALUE_LIST	NULL
+READ_ONLY	YES
+COMMAND_LINE_ARGUMENT	NULL
 VARIABLE_NAME	SESSION_TRACK_SCHEMA
 VARIABLE_SCOPE	SESSION
 VARIABLE_TYPE	BOOLEAN

plugin/feedback/feedback.cc

@@ -26,10 +26,8 @@ namespace feedback {
 ulong debug_startup_interval, debug_first_interval, debug_interval;
 #endif
 
-char server_uid_buf[SERVER_UID_SIZE+1]; ///< server uid will be written here
-
 /* backing store for system variables */
-static char *server_uid= server_uid_buf, *url, *http_proxy;
+static char *url, *http_proxy;
 char *user_info;
 ulong send_timeout, send_retry_wait;
 
@@ -254,9 +252,6 @@ static int init(void *p)
   PSI_register(cond);
   PSI_register(thread);
 
-  if (calculate_server_uid(server_uid_buf))
-    return 1;
-
   prepare_linux_info();
 
 #ifndef DBUG_OFF
@@ -362,9 +357,6 @@ static int free(void *p)
 #define DEFAULT_PROTO "http://"
 #endif
 
-static MYSQL_SYSVAR_STR(server_uid, server_uid,
-       PLUGIN_VAR_READONLY | PLUGIN_VAR_NOCMDOPT,
-       "Automatically calculated server unique id hash.", NULL, NULL, 0);
 static MYSQL_SYSVAR_STR(user_info, user_info,
        PLUGIN_VAR_READONLY | PLUGIN_VAR_RQCMDARG,
        "User specified string that will be included in the feedback report.",
@@ -395,7 +387,6 @@ static MYSQL_SYSVAR_ULONG(debug_interval, debug_interval,
 #endif
 
 static struct st_mysql_sys_var* settings[] = {
-  MYSQL_SYSVAR(server_uid),
   MYSQL_SYSVAR(user_info),
   MYSQL_SYSVAR(url),
   MYSQL_SYSVAR(send_timeout),

plugin/feedback/feedback.h

@@ -25,8 +25,7 @@ int fill_misc_data(THD *thd, TABLE_LIST *tables);
 int fill_linux_info(THD *thd, TABLE_LIST *tables);
 int fill_collation_statistics(THD *thd, TABLE_LIST *tables);
 
-static const int SERVER_UID_SIZE= 29;
-extern char server_uid_buf[SERVER_UID_SIZE+1], *user_info;
+extern char *user_info;
 int calculate_server_uid(char *);
 int prepare_linux_info();
 

plugin/feedback/sender_thread.cc

@@ -183,7 +183,7 @@ static void send_report(const char *when)
     str.length(0);
     str.append(STRING_WITH_LEN("FEEDBACK_SERVER_UID"));
     str.append('\t');
-    str.append(server_uid_buf);
+    str.append(server_uid);
     str.append('\n');
     str.append(STRING_WITH_LEN("FEEDBACK_WHEN"));
     str.append('\t');

plugin/feedback/utils.cc

@@ -412,31 +412,4 @@ int fill_collation_statistics(THD *thd, TABLE_LIST *tables)
   }
   return 0;
 };
-
-/**
-  calculates the server unique identifier
-  
-  UID is a base64 encoded SHA1 hash of the MAC address of one of
-  the interfaces, and the tcp port that the server is listening on
-*/
-int calculate_server_uid(char *dest)
-{
-  uchar rawbuf[2 + 6];
-  uchar shabuf[MY_SHA1_HASH_SIZE];
-
-  int2store(rawbuf, mysqld_port);
-  if (my_gethwaddr(rawbuf + 2))
-  {
-    sql_print_error("feedback plugin: failed to retrieve the MAC address");
-    return 1;
-  }
-
-  my_sha1((uint8*) shabuf, (char*) rawbuf, sizeof(rawbuf));
-
-  assert(my_base64_needed_encoded_length(sizeof(shabuf)) <= SERVER_UID_SIZE);
-  my_base64_encode(shabuf, sizeof(shabuf), dest);
-
-  return 0;
-}
-
 } // namespace feedback

sql/mysqld.cc

@@ -352,6 +352,8 @@ LEX_STRING opt_init_connect, opt_init_slave;
 static DYNAMIC_ARRAY all_options;
 static longlong start_memory_used;
 
+char server_uid[SERVER_UID_SIZE+1];   // server uid will be written here
+
 /* Global variables */
 
 bool opt_bin_log, opt_bin_log_used=0, opt_ignore_builtin_innodb= 0;
@@ -1130,6 +1132,8 @@ PSI_file_key key_file_map;
 PSI_statement_info stmt_info_new_packet;
 #endif
 
+static int calculate_server_uid(char *dest);
+
 #ifndef EMBEDDED_LIBRARY
 void net_before_header_psi(struct st_net *net, void *thd, size_t /* unused: count */)
 {
@@ -3872,6 +3876,9 @@ static int init_common_variables()
   if (IS_SYSVAR_AUTOSIZE(&server_version_ptr))
     set_server_version(server_version, sizeof(server_version));
 
+  if (calculate_server_uid(server_uid))
+    strmov(server_uid, "unknown");
+
   mysql_real_data_home_len= uint(strlen(mysql_real_data_home));
 
   sf_leaking_memory= 0; // no memory leaks from now on
@@ -4735,8 +4742,10 @@ static int init_server_components()
     first in error log, for troubleshooting and debugging purposes
   */
   if (!opt_help)
-    sql_print_information("Starting MariaDB %s source revision %s as process %lu",
-                          server_version, SOURCE_REVISION, (ulong) getpid());
+    sql_print_information("Starting MariaDB %s source revision %s "
+                          "server_uid %s as process %lu",
+                          server_version, SOURCE_REVISION, server_uid,
+                          (ulong) getpid());
 
 #ifdef WITH_PERFSCHEMA_STORAGE_ENGINE
   /*
@@ -9849,3 +9858,31 @@ my_thread_id next_thread_id(void)
   mysql_mutex_unlock(&LOCK_thread_id);
   return retval;
 }
+
+
+/**
+  calculates the server unique identifier
+
+  UID is a base64 encoded SHA1 hash of the MAC address of one of
+  the interfaces, and the tcp port that the server is listening on
+*/
+
+static int calculate_server_uid(char *dest)
+{
+  uchar rawbuf[2 + 6];
+  uchar shabuf[MY_SHA1_HASH_SIZE];
+
+  int2store(rawbuf, mysqld_port);
+  if (my_gethwaddr(rawbuf + 2))
+  {
+    sql_print_error("feedback plugin: failed to retrieve the MAC address");
+    return 1;
+  }
+
+  my_sha1((uint8*) shabuf, (char*) rawbuf, sizeof(rawbuf));
+
+  assert(my_base64_needed_encoded_length(sizeof(shabuf)) <= SERVER_UID_SIZE);
+  my_base64_encode(shabuf, sizeof(shabuf), dest);
+
+  return 0;
+}

sql/mysqld.h

@@ -957,6 +957,8 @@ extern my_bool opt_mysql56_temporal_format, strict_password_validation;
 extern ulong binlog_checksum_options;
 extern bool max_user_connections_checking;
 extern ulong opt_binlog_dbug_fsync_sleep;
+static const int SERVER_UID_SIZE= 29;
+extern char server_uid[SERVER_UID_SIZE+1];
 
 extern uint volatile global_disable_checkpoint;
 extern my_bool opt_help;

sql/sys_vars.cc

@@ -3273,6 +3273,14 @@ Sys_server_id(
        VALID_RANGE(1, UINT_MAX32), DEFAULT(1), BLOCK_SIZE(1), NO_MUTEX_GUARD,
        NOT_IN_BINLOG, ON_CHECK(check_server_id), ON_UPDATE(fix_server_id));
 
+char *server_uid_ptr= &server_uid[0];
+
+static Sys_var_charptr Sys_server_uid(
+      "server_uid", "Automatically calculated server unique id hash",
+       READ_ONLY GLOBAL_VAR(server_uid_ptr),
+       CMD_LINE_HELP_ONLY,
+       DEFAULT(server_uid));
+
 static Sys_var_on_access_global<Sys_var_mybool,
                           PRIV_SET_SYSTEM_GLOBAL_VAR_SLAVE_COMPRESSED_PROTOCOL>
 Sys_slave_compressed_protocol(