Increase max user name length to 80

Summary:
This mitigates upstream bug: http://bugs.mysql.com/3083

User name length limit of 16 was too short, so made it 80.

80 is effectively the limit without making additional changes
because of MyISAM's 1000 byte limit on key length and the
primary key of mysql.columns_priv. To compute the size of
the key for that table, the lengths of the char fields are
summed and then multipled by 3, resulting in a limit on the
max size of user name lengths being 81 characters.

Test Plan:
Added long user names to basic grant and replication tests.

Did full build and test run without perfschema, no failures.

Did full build and test run with perfschema, no new failures.

Jenkins both 'arc unit', and 'arc unit --everything', pass

Built a test rpm, ran it through rpm tests, passed.

Installed the test rpm on a test server, then downgraded it:
"use mysql; show create table user;", and got:
* Before upgrade: "...`User` char(16)..."
* After upgrade: "...`User` char(16)..."
* After restart: "...`User` char(16)..."
* After running mysql_upgrade: "...`User` char(80)..."
* After downgrade: "...`User` char(80)..."
* After restart: "...`User` char(80)..."
* After running mysql_upgrade: "...`User` char(16)..."

Reviewers: rudradevbasak, jtolmer, chip, santoshb

Reviewed By: santoshb

Author: steaphangreene

include/mysql.h.pp

@@ -511,7 +511,7 @@
   socklen_t len;
   unsigned long pkt_length;
   char *host_info;
-  char buff[(64*3)+(16*3)+100];
+  char buff[(64*3)+(80*3)+100];
   int scramble_data_len;
   int pkt_scramble_len;
   char *scramble_data;

include/mysql/plugin_auth.h.pp

@@ -288,7 +288,7 @@
   unsigned int user_name_length;
   const char *auth_string;
   unsigned long auth_string_length;
-  char authenticated_as[48 +1];
+  char authenticated_as[240 +1];
   char external_user[512];
   int password_used;
   const char *host_or_ip;

include/mysql/plugin_auth_common.h

@@ -22,8 +22,12 @@
 */
 #define MYSQL_PLUGIN_AUTH_COMMON_INCLUDED
 
-/** the max allowed length for a user name */
-#define MYSQL_USERNAME_LENGTH 48
+/**
+   The max allowed length for a user name. Equivalent to USERNAME_LENGTH
+   which is USERNAME_CHAR_LENGTH*SYSTEM_CHARSET_MBMAXLEN.
+*/
+
+#define MYSQL_USERNAME_LENGTH 240
 
 /**
   return values of the plugin authenticate_user() method.

include/mysql_com.h

@@ -23,7 +23,7 @@
 #define HOSTNAME_LENGTH 60
 #define SYSTEM_CHARSET_MBMAXLEN 3
 #define NAME_CHAR_LEN	64              /* Field/table name length */
-#define USERNAME_CHAR_LENGTH 16
+#define USERNAME_CHAR_LENGTH 80
 #define NAME_LEN                (NAME_CHAR_LEN*SYSTEM_CHARSET_MBMAXLEN)
 #define USERNAME_LENGTH         (USERNAME_CHAR_LENGTH*SYSTEM_CHARSET_MBMAXLEN)
 

mysql-test/r/create.result

@@ -1891,7 +1891,7 @@ show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
   `ID` bigint(21) unsigned NOT NULL DEFAULT '0',
-  `USER` varchar(16) NOT NULL DEFAULT '',
+  `USER` varchar(80) NOT NULL DEFAULT '',
   `HOST` varchar(64) NOT NULL DEFAULT '',
   `DB` varchar(64) DEFAULT NULL,
   `COMMAND` varchar(16) NOT NULL DEFAULT '',
@@ -1905,7 +1905,7 @@ show create table t1;
 Table	Create Table
 t1	CREATE TEMPORARY TABLE `t1` (
   `ID` bigint(21) unsigned NOT NULL DEFAULT '0',
-  `USER` varchar(16) NOT NULL DEFAULT '',
+  `USER` varchar(80) NOT NULL DEFAULT '',
   `HOST` varchar(64) NOT NULL DEFAULT '',
   `DB` varchar(64) DEFAULT NULL,
   `COMMAND` varchar(16) NOT NULL DEFAULT '',

mysql-test/r/func_system.result

@@ -47,7 +47,7 @@ show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
   `database()` varchar(34) CHARACTER SET utf8 DEFAULT NULL,
-  `user()` varchar(77) CHARACTER SET utf8 NOT NULL DEFAULT '',
+  `user()` varchar(141) CHARACTER SET utf8 NOT NULL DEFAULT '',
   `version` char(60) DEFAULT NULL
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;

mysql-test/r/grant.result

@@ -753,7 +753,7 @@ columns.TABLE_CATALOG, columns.TABLE_SCHEMA, columns.COLUMN_DEFAULT, columns.IS_
 from information_schema.statistics join information_schema.columns using(table_name,column_name) where table_name='user';
 TABLE_NAME	COLUMN_NAME	TABLE_CATALOG	TABLE_SCHEMA	NON_UNIQUE	INDEX_SCHEMA	INDEX_NAME	SEQ_IN_INDEX	COLLATION	SUB_PART	PACKED	NULLABLE	INDEX_TYPE	COMMENT	TABLE_CATALOG	TABLE_SCHEMA	COLUMN_DEFAULT	IS_NULLABLE	DATA_TYPE	CHARACTER_MAXIMUM_LENGTH	CHARACTER_OCTET_LENGTH	NUMERIC_PRECISION	NUMERIC_SCALE	CHARACTER_SET_NAME	COLLATION_NAME	COLUMN_TYPE	COLUMN_KEY	EXTRA	COLUMN_COMMENT
 user	Host	def	mysql	0	mysql	PRIMARY	1	A	NULL	NULL		BTREE		def	mysql		NO	char	60	180	NULL	NULL	utf8	utf8_bin	char(60)	PRI		
-user	User	def	mysql	0	mysql	PRIMARY	2	A	NULL	NULL		BTREE		def	mysql		NO	char	16	48	NULL	NULL	utf8	utf8_bin	char(16)	PRI		
+user	User	def	mysql	0	mysql	PRIMARY	2	A	NULL	NULL		BTREE		def	mysql		NO	char	80	240	NULL	NULL	utf8	utf8_bin	char(80)	PRI		
 drop table t1;
 drop table t2;
 drop table t3;

mysql-test/r/join.result

@@ -26,9 +26,9 @@ SHOW CREATE TABLE mysql.proxies_priv;
 Table	Create Table
 proxies_priv	CREATE TABLE `proxies_priv` (
   `Host` char(60) COLLATE utf8_bin NOT NULL DEFAULT '',
-  `User` char(16) COLLATE utf8_bin NOT NULL DEFAULT '',
+  `User` char(80) COLLATE utf8_bin NOT NULL DEFAULT '',
   `Proxied_host` char(60) COLLATE utf8_bin NOT NULL DEFAULT '',
-  `Proxied_user` char(16) COLLATE utf8_bin NOT NULL DEFAULT '',
+  `Proxied_user` char(80) COLLATE utf8_bin NOT NULL DEFAULT '',
   `With_grant` tinyint(1) NOT NULL DEFAULT '0',
   `Grantor` char(77) COLLATE utf8_bin NOT NULL DEFAULT '',
   `Timestamp` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,

mysql-test/r/plugin_auth.result

@@ -5270,11 +5270,11 @@ use test|
 drop table t3|
 DROP PROCEDURE IF EXISTS bug16899_p1|
 DROP FUNCTION IF EXISTS bug16899_f1|
-CREATE DEFINER=1234567890abcdefGHIKL@localhost PROCEDURE bug16899_p1()
+CREATE DEFINER=abcdefghij1234567890abcdefghij1234567890abcdefghij1234567890abcdefghij1234567890a@localhost PROCEDURE bug16899_p1()
 BEGIN
 SET @a = 1;
 END|
-ERROR HY000: String '1234567890abcdefGHIKL' is too long for user name (should be no longer than 16)
+ERROR HY000: String 'abcdefghij1234567890abcdefghij1234567890abcdefghij1234567890abcdefghij' is too long for user name (should be no longer than 80)
 CREATE DEFINER=some_user_name@1234567890abcdefghij1234567890abcdefghij1234567890abcdefghijQWERTY
 FUNCTION bug16899_f1() RETURNS INT
 BEGIN