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Added max_user_connections

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This commit is contained in:
monty@donna.mysql.com
2001-02-21 01:11:32 +02:00
parent 96a860811e
commit 70a627a1db
5 changed files with 178 additions and 25 deletions
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134
sql/sql_parse.cc
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@ -22,6 +22,7 @@
#include <thr_alarm.h>
#include <myisam.h>
#include <my_dir.h>
#include <assert.h>
#define SCRAMBLE_LENGTH 8
@ -32,6 +33,9 @@ extern "C" pthread_mutex_t THR_LOCK_keycache;
extern "C" int gethostname(char *name, int namelen);
#endif
static int check_for_max_user_connections(const char *user, int u_length,
const char *host);
static void decrease_user_connections(const char *user, const char *host);
static bool check_table_access(THD *thd,uint want_access, TABLE_LIST *tables);
static bool check_db_used(THD *thd,TABLE_LIST *tables);
static bool check_merge_table_access(THD *thd, char *db, TABLE_LIST *tables);
@ -145,13 +149,134 @@ static bool check_user(THD *thd,enum_server_command command, const char *user,
thd->host ? thd->host : thd->ip ? thd->ip : "unknown ip",
db ? db : (char*) "");
thd->db_access=0;
if (max_user_connections &&
check_for_max_user_connections(user, strlen(user), thd->host))
return -1;
if (db && db[0])
return test(mysql_change_db(thd,db));
{
bool error=test(mysql_change_db(thd,db));
if (error)
decrease_user_connections(user,thd->host);
return error;
}
else
send_ok(net); // Ready to handle questions
return 0; // ok
}
/*
** check for maximum allowable user connections
** if mysql server is started with corresponding
** variable that is greater then 0
*/
static HASH hash_user_connections;
static DYNAMIC_ARRAY user_conn_array;
extern pthread_mutex_t LOCK_user_conn;
struct user_conn {
char user[USERNAME_LENGTH+HOSTNAME_LENGTH+2];
int connections, len;
};
static byte* get_key_conn(user_conn *buff, uint *length,
my_bool not_used __attribute__((unused)))
{
*length=buff->len;
return (byte*) buff->user;
}
#define DEF_USER_COUNT 50
void init_max_user_conn(void)
{
(void) hash_init(&hash_user_connections,DEF_USER_COUNT,0,0,
(hash_get_key) get_key_conn,0, 0);
(void) init_dynamic_array(&user_conn_array,sizeof(user_conn),
DEF_USER_COUNT, DEF_USER_COUNT);
}
static int check_for_max_user_connections(const char *user, int u_length,
const char *host)
{
uint temp_len;
char temp_user[USERNAME_LENGTH+HOSTNAME_LENGTH+2];
struct user_conn *uc;
if (!user)
user="";
if (!host)
host="";
temp_len= (uint) (strxnmov(temp_user, sizeof(temp_user), user, "@", host,
NullS) - temp_user);
(void) pthread_mutex_lock(&LOCK_user_conn);
uc = (struct user_conn *) hash_search(&hash_user_connections,
(byte*) temp_user, temp_len);
if (uc) /* user found ; check for no. of connections */
{
if (max_user_connections == uc->connections)
{
net_printf(&(current_thd->net),ER_TOO_MANY_USER_CONNECTIONS, temp_user);
pthread_mutex_unlock(&LOCK_user_conn);
return 1;
}
uc->connections++;
}
else
{
/* the user is not found in the cache; Insert it */
struct user_conn uc;
memcpy(uc.user,temp_user,temp_len+1);
uc.len = temp_len;
uc.connections = 1;
if (!insert_dynamic(&user_conn_array, (char *) &uc))
{
hash_insert(&hash_user_connections,
(byte *) dynamic_array_ptr(&user_conn_array,
user_conn_array.elements - 1));
}
}
(void) pthread_mutex_unlock(&LOCK_user_conn);
return 0;
}
static void decrease_user_connections(const char *user, const char *host)
{
char temp_user[USERNAME_LENGTH+HOSTNAME_LENGTH+2];
int temp_len;
struct user_conn uucc, *uc;
if (!user)
user="";
if (!host)
host="";
temp_len= (uint) (strxnmov(temp_user, sizeof(temp_user), user, "@", host,
NullS) - temp_user);
(void) pthread_mutex_lock(&LOCK_user_conn);
uc = (struct user_conn *) hash_search(&hash_user_connections,
(byte*) temp_user, temp_len);
dbug_assert(uc != 0); // We should always find the user
if (!uc)
goto end; // Safety; Something went wrong
if (! --uc->connections)
{
/* Last connection for user; Delete it */
(void) hash_delete(&hash_user_connections,(char *) uc);
uint element= ((uint) ((byte*) uc - (byte*) user_conn_array.buffer) /
user_conn_array.size_of_element);
delete_dynamic_element(&user_conn_array,element);
}
end:
(void) pthread_mutex_unlock(&LOCK_user_conn);
}
void free_max_user_conn(void)
{
delete_dynamic(&user_conn_array);
hash_free(&hash_user_connections);
}
/*
** check connnetion and get priviliges
@ -417,6 +542,8 @@ pthread_handler_decl(handle_one_connection,arg)
thread_safe_increment(aborted_threads,&LOCK_thread_count);
}
if (max_user_connections)
decrease_user_connections(thd->user,thd->host);
end_thread:
close_connection(net);
end_thread(thd,1);
@ -512,7 +639,7 @@ int mysql_table_dump(THD* thd, char* db, char* tbl_name, int fd)
DBUG_ENTER("mysql_table_dump");
db = (db && db[0]) ? db : thd->db;
if (!(table_list = (TABLE_LIST*) sql_calloc(sizeof(TABLE_LIST))))
DBUG_RETURN(1); // out of memory
DBUG_RETURN(1); // out of memory
table_list->db = db;
table_list->real_name = table_list->name = tbl_name;
table_list->lock_type = TL_READ_NO_INSERT;
@ -641,7 +768,7 @@ bool do_command(THD *thd)
send_error(net, ER_UNKNOWN_COM_ERROR);
break;
}
if (check_user(thd, COM_CHANGE_USER, user, passwd, db,0))
if (check_user(thd, COM_CHANGE_USER, user, passwd, db, 0))
{ // Restore old user
x_free(thd->user);
x_free(thd->db);
@ -652,6 +779,7 @@ bool do_command(THD *thd)
thd->priv_user=save_priv_user;
break;
}
decrease_user_connections (save_user, thd->host);
x_free((gptr) save_db);
x_free((gptr) save_user);
thd->password=test(passwd[0]);