call external script with mySQL trigger WHITOUT sys_exec on ubuntu ARMHF - mysql

Question

I need to call an external script from a trigger to intercept every insert in the DB.
This because I can't poll for that value, I'm coding for an embedded system with ARM architecture and only 250MB of RAM.
Trigger is the right options, and the code of the trigger works well, I get:
FUNCTION mydb.sys_exec does not exist (MySQL error code: 1305, SQLState: 42000 )
so I tried to install this:
https://github.com/mysqludf/lib_mysqludf_sys
but it gets me:
ERROR: You need libmysqlclient development software installed
to be able to compile this UDF, on Debian/Ubuntu just run:
apt-get install libmysqlclient15-dev
so if I type
sudo apt-get install libmysqlclient15-dev
I get:
Note, selecting 'libmysqlclient-dev' instead of 'libmysqlclient15-dev'
and of course it is not the right package because it doesn't work.
The .so file contained in the git is compiled for intelx86.
Anyone has an idea?
Compiling the .c in the git it's quite impossible due the lot of missing dependencies.
Or.. how can I execute an external script from a trigger without sys_exec?
PS: for completeness, this is the trigger script:
DELIMITER ##
CREATE TRIGGER command_controller
AFTER INSERT ON myDB.foo
FOR EACH ROW
BEGIN
DECLARE cmd CHAR(255);
DECLARE result int(10);
SET cmd='./foo ';
SET result = sys_eval(cmd);
END;
##
DELIMITER ;

Answer 1

Here's a minimal version that works for me:
#include <string.h>
#include <stdlib.h>
#include <mysql.h>
my_bool sys_exec_init(
UDF_INIT *initid
, UDF_ARGS *args
, char *message
){
unsigned int i=0;
if(args->arg_count == 1
&& args->arg_type[i]==STRING_RESULT){
return 0;
} else {
strcpy(
message
, "Expected exactly one string type parameter"
);
return 1;
}
}
void sys_exec_deinit(
UDF_INIT *initid
){
}
my_ulonglong sys_exec(
UDF_INIT *initid
, UDF_ARGS *args
, char *is_null
, char *error
){
return system(args->args[0]);
}
I compile it with this line:
gcc -Wall -I include -I /home/rbouman/mysql/mysql-5.6.10-linux-glibc2.5-x86_64/include -shared -fPIC -o sys_exec.so sys_exec.c