Mysql 5.5 LOAD DATA INFILE Permissions - c++

Question

ERROR The used command is not allowed with this MySQL version
I am having problems migrating some mysqlclient C++ code from Mysql 5.1 to 5.5 (using soci). The C++ part is not so relevant - the problem is writing some mysqlclient code which can successfully do a LOAD DATA INFILE on MySQL 5.5.
Here are my notes (LOAD DATA INFILE fails, but normal queries are ok):
The code below works fine on Mysql 5.1, gcc 4.6.1, Oneiric
The same code fails on Mysql 5.5, gcc 4.7.2, Quantal
If I LOAD DATA INFILE from mysql (the command-line client), it works fine (I have updated my.cnf with local-infile=1)
mysql> show variables like '%local_infile%'; results in ON
It would be great if there were a SOCI or a configuration solution to this, but if someone has managed to get this to work with libmysqlclient, that would be great to know, too...
#include <soci.h>
#include <mysql/soci-mysql.h>
#include <string>
#include <iostream>
using soci::use;
using namespace std;
using namespace soci;
main()
{
string val =
"mysql://" +
"host=127.0.0.1" +
" dbname=tmp_db" +
" user=root" +
" password=open_sasame";
int sum;
session sql( val );
sql << "SELECT 1+1", into( sum );
cerr << "RESULT=" << sum << endl; // works fine
// NEXT LINE FAILS WITH:
// The used command is not allowed with this MySQL version
sql << "LOAD DATA LOCAL INFILE '/tmp/junk3.txt' INTO TABLE tmp_db.example_tbl FIELDS TERMINATED BY '|' LINES TERMINATED BY '\\n'";
}

Answer 1

The answer is, we need the following line of code:
mysql_options( &mysql, MYSQL_OPT_LOCAL_INFILE, 0 );
inserted between mysql_init() and mysql_real_connect().
Below is a snippet of C code for reference. Note that SOCI's mysql backend can be patched with this line of code for it to work.
Tested and works on Mysql 5.5, gcc 4.7.2, Quantal.
#include <mysql.h>
#include <stdio.h>
main()
{
MYSQL mysql;
mysql_init( &mysql );
mysql_options( &mysql, MYSQL_OPT_LOCAL_INFILE, 0 );
if ( !mysql_real_connect( &mysql,"127.0.0.1","root","open_sasame","tmp_db",0,NULL,0 ))
{
fprintf(stderr, "Failed to connect to database: Error: %s\n",
mysql_error( &mysql ));
}
if ( mysql_query( &mysql, "LOAD DATA LOCAL INFILE '/tmp/junk4.txt' "
"INTO TABLE tmp_db.example_tbl FIELDS TERMINATED BY '|' "
"LINES TERMINATED BY '\\n'" ))
{
fprintf( stderr, "ERROR DURING LOAD DATA LOCAL INFILE\n" );
}
mysql_close( &mysql );
}