You would probably want to use the general query log.
The general query log is a general
record of what mysqld is doing. The
server writes information to this log
when clients connect or disconnect,
and it logs each SQL statement
received from clients.
One important thing with logging for security is that an attacker cannot access the log to erase traces of their presence, so consider append-only files.
FWIW in Oracle we can send logs automatically to a remote syslog, but I don't believe MySQL has this feature yet. Perhaps you could fake it with SNMP but I have not tried it.
You didn't say, in your question what the "file not present" message was, but I'm guessing it's this:
ERROR 1126 (HY000) at line 29: Can't open shared library 'lib_mysqludf_sys.so'
(errno: 0 /usr/local/mysql/lib/plugin/lib_mysqludf_sys.so: cannot open shared
object file: No such file or directory)
ERROR: unable to install the UDF
That makes sense, because you're telling gcc to write the file to /usr/lib/lib_mysqludf_sys.so... that's the -o option in your command line. Give gcc the path MySQL is expecting and the rest of the installation should work.
gcc -m64 -fPIC -Wall -I/usr/include/mysql -I. -shared lib_mysqludf_sys.c \
-o /usr/local/mysql/lib/plugin/lib_mysqludf_sys.so \
-L/usr/lib/x86_64-linux-gnu/libstdc++.so.6
Also, whatever you're planning to do with this... don't say I didn't recommend against it. You're introducing both a potential security vulnerability and potentional performance and stability liability if these tools are deployed. This is not because there's anything wrong with the utility, but because of the amount of somewhat unorthodox functionality it opens up.
It's pretty cool, I admit. The lib_mysqludf_sys group of user-defined functions allow some interesting but easily-misappropriated capabilities, letting you spawn system commands and get either their generated output with sys_eval() or their return value with sys_exec() but really, I tend to suspect there's a reason why MySQL doesn't have these capabilities built in.
mysql> select sys_eval('df -k | grep xvda | tr -d "\n"') as cool_function_but_bad_idea;
+-----------------------------------------------------+
| cool_function_but_bad_idea |
+-----------------------------------------------------+
| /dev/xvda1 8256952 1216636 6620888 16% / |
+-----------------------------------------------------+
1 row in set (0.81 sec)
mysql> select sys_exec('/bin/false'), sys_exec('/bin/true');
+------------------------+-----------------------+
| sys_exec('/bin/false') | sys_exec('/bin/true') |
+------------------------+-----------------------+
| 256 | 0 |
+------------------------+-----------------------+
1 row in set (1.59 sec)
Update to address this error message:
gcc -Wall -m64 -I/usr/include/mysql -I. -shared lib_mysqludf_sys.c -o
/usr/lib/lib_mysqludf_sys.so -fPIC gcc: error: lib_mysqludf_sys.c: No such
file or directory gcc: fatal error: no input files compilation terminated
The statement in question is directing "gcc" to compile a 64-bit version from the source code, which is found in lib_mysqludf_sys.c. This is one of the files you downloaded, so, to compile it, you need to be inside the directory where you downloaded the lib_mysqludf_sys files. This error suggests that you aren't. The download package isn't limited to 32 bit, it's just that it only builds a 32 bit version unless you use the gcc -m64 -fPIC ... statement.
Best Answer
errno: 13 should be enough of a clue here. 13 is generally permission denied. Check the .so file in your plugindir. It will likely have privs that will prevent the user running MySQL from opening it.