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Fix crash when multiple MySQL monitors monitor same servers

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The monitors always freed and reallocated the memory for the slaves. It
was always of the same size so a static array of that size should also
work.
This commit is contained in:
Markus Makela
2016-09-08 09:46:46 +03:00
parent 4940e1482f
commit a474dad753
4 changed files with 7 additions and 12 deletions
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1
server/core/server.c
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@ -81,7 +81,6 @@ server_alloc(char *servname, char *protocol, unsigned short port)
server->rlag = -2;
server->master_id = -1;
server->depth = -1;
server->slaves = NULL;
server->parameters = NULL;
server->server_string = NULL;
spinlock_init(&server->lock);

1
server/include/monitor.h
View File

@ -129,7 +129,6 @@ typedef enum
#define MONITOR_INTERVAL 10000 // in milliseconds
#define MONITOR_DEFAULT_ID 1UL // unsigned long value
#define MONITOR_MAX_NUM_SLAVES 20 //number of MySQL slave servers associated to a MySQL master server
/*
* Create declarations of the enum for monitor events and also the array of

3
server/include/server.h
View File

@ -45,6 +45,7 @@
*/
#define MAX_SERVER_NAME_LEN 1024
#define MAX_NUM_SLAVES 128 /**< Maximum number of slaves under a single server*/
/**
* The server parameters used for weighting routing decissions
@ -99,7 +100,7 @@ typedef struct server
SERVER_PARAM *parameters; /**< Parameters of a server that may be used to weight routing decisions */
long master_id; /**< Master server id of this node */
int depth; /**< Replication level in the tree */
long *slaves; /**< Slaves of this node */
long slaves[MAX_NUM_SLAVES]; /**< Slaves of this node */
bool master_err_is_logged; /*< If node failed, this indicates whether it is logged */
DCB *persistent; /**< List of unused persistent connections to the server */
SPINLOCK persistlock; /**< Lock for adjusting the persistent connections list */

14
server/modules/monitor/mysql_mon.c
View File

@ -550,7 +550,7 @@ static MONITOR_SERVERS *build_mysql51_replication_tree(MONITOR *mon)
if (mysql_num_rows(result) > 0)
{
ismaster = true;
while (nslaves < MONITOR_MAX_NUM_SLAVES && (row = mysql_fetch_row(result)))
while (nslaves < MAX_NUM_SLAVES && (row = mysql_fetch_row(result)))
{
/* get Slave_IO_Running and Slave_SQL_Running values*/
database->server->slaves[nslaves] = atol(row[0]);
@ -838,12 +838,7 @@ monitorMain(void *arg)
monitorDatabase(mon, ptr);
/* reset the slave list of current node */
if (ptr->server->slaves)
{
free(ptr->server->slaves);
}
/* create a new slave list */
ptr->server->slaves = (long *) calloc(MONITOR_MAX_NUM_SLAVES, sizeof(long));
memset(&ptr->server->slaves, 0, sizeof(ptr->server->slaves));
num_servers++;
@ -1450,7 +1445,8 @@ static MONITOR_SERVERS *get_replication_tree(MONITOR *mon, int num_servers)
master = getServerByNodeId(mon->databases, current->master_id);
if (master && master->server && master->server->node_id > 0)
{
add_slave_to_master(master->server->slaves, MONITOR_MAX_NUM_SLAVES, current->node_id);
add_slave_to_master(master->server->slaves, sizeof(master->server->slaves),
current->node_id);
master->server->depth = current->depth - 1;
monitor_set_pending_status(master, SERVER_MASTER);
handle->master = master;
@ -1511,7 +1507,7 @@ static int add_slave_to_master(long *slaves_list, int list_size, long node_id)
{
if (slaves_list[i] == 0)
{
memcpy(&slaves_list[i], &node_id, sizeof(long));
slaves_list[i] = node_id;
return 1;
}
}