hholzgra / connector-c-examples Goto Github PK

Right now the mysql_ssl_set example contains MariaDB specific code, in the long run it should work with both MariaDB and MySQL

This is especially needed on the MariaDB side when trying to use mariadb_*() functions like mariadb_get_infov()

See also Issue #5

Hi.
I wrote the following code based on your MySQL access demo.
I want to run this to create a database.
Please give me some advice to build this program.
Written in *.c in Visual Studio 2019.
Is it executable in Visual Studio 2019?
Which field of Visual Studio 2019 should you try to create?
What is MySQL library?
Isn't my.CNF file possible in Ubuntu system?
How do I build and run this on Ubuntu?
Please explain it step by step.
Thank you.

#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/epoll.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/timerfd.h>
#include <sys/types.h>
#include <sys/resource.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <time.h>
#include <unistd.h>
#include <pthread.h>
#include <netdb.h>
#include <time.h>
#include <netinet/in.h>
#include <mysql.h>
#include <curl/curl.h>
#include <ctype.h>

MYSQL *mysql_con;

void
mysql_start()
{
mysql_con = mysql_init(NULL);
if (mysql_con == NULL)
{
fprintf(stderr, "%s\n", mysql_error(mysql_con));
exit(1);
}

if (mysql_real_connect(mysql_con, "localhost", "happy", "123456", "happy", 0, NULL, 0) == NULL)
{
	fprintf(stderr, "%s\n", mysql_error(mysql_con));
	exit(EXIT_FAILURE);
}

if (mysql_query(mysql_con, "CREATE TABLE IF NOT EXISTS `frontier` (`url` varchar(2084) NOT NULL, `id` int NOT NULL AUTO_INCREMENT, PRIMARY KEY (`id`), UNIQUE KEY `url` (`url`)) ENGINE=InnoDB AUTO_INCREMENT=1"))
{
	fprintf(stderr, "%s\n", mysql_error(mysql_con));
	mysql_stop();
            exit(1);
}

if (mysql_query(mysql_con, "CREATE TABLE IF NOT EXISTS `crawled` (`id` int NOT NULL AUTO_INCREMENT, `url` varchar(2084) DEFAULT NULL, `title` varchar(768) DEFAULT NULL, `date` varchar(128) DEFAULT NULL, `last_modified` varchar(128) DEFAULT NULL, `links` int DEFAULT NULL, `backlinks` int DEFAULT NULL, `http_code` int DEFAULT NULL, PRIMARY KEY (`id`), UNIQUE KEY `url` (`url`), KEY `http_code` (`http_code`), KEY `title` (`title`)) ENGINE=InnoDB AUTO_INCREMENT=1"))
{
	fprintf(stderr, "%s\n", mysql_error(mysql_con));
            mysql_stop();
            exit(1);
}

if (mysql_query(mysql_con, "CREATE TABLE IF NOT EXISTS `emails` (`email` varchar(2084) NOT NULL, `id` int NOT NULL AUTO_INCREMENT, PRIMARY KEY (`id`), UNIQUE KEY `email` (`email`)) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=latin1"))
{
	fprintf(stderr, "%s\n", mysql_error(mysql_con));
            mysql_stop();
            exit(1);
}

}
void
mysql_stop()
{
mysql_close(mysql_con);
}
int
main(int argc, char **argv)
{
int cleanup = 0, opt, ret;

mysql_start();
mysql_stop();


printf("Exiting.\n");

return (0);

}

For learning resources such as examples maybe a very permissive license such as MIT would be a better fit?

right now all examples have the full initialization and connect code in their respective source files, this makes finding the actual example code for the function at had hard for the casual reader

I'm not sure if it is fair to raise an issue report here...

The mysql_real_escape_string example does not show how to avoid a buffer overflow on to. The best I can tell, the function is unsafe because it does not take a destination buffer size. Attacker controlled input to the function can simply enlist enough escapes to exceed the 201 character destination buffer.

For convenience here is the function:

const char *from = "\\";
char to[201];
unsigned long len;

len = mysql_real_escape_string(mysql, to, from, strlen(from));
to[len] = '\0';
printf("Escaped string is: \"%s\" (%lu)\n", to, len);

My apologies if I am parsing things incorrectly.

(I'm here because the MySQL example seems to have the same problem, and the MariaDB example does not exist).

When using libmariadb dev packages only mariadb_config gets installed by default, mysql_config gets created as a symlink to mariadb_config only if libmariadb-dev-compat is also installed

The autoconf macros should check for both names