Silvio Donnini's questions

I am trying to delete a file created with a SELECT ... INTO OUTFILE statement into the /tmp directory

The file belongs to the mysql user (who doesn't have a login shell).

I have administrative privileges on the database (i.e. I can login into mysql as the root user), but I don't have the root password of the machine onto which the service runs.

Is there a way to delete the file myself, or do I need to relay the task to the administrator of that machine each time?

thanks,

Silvio

In my network, there is a machine which has to make a http request towards a server which is beyond a firewall.

This machine's ip address (as seen from beyond the firewall) can be chosen from a pool of about 5 addresses.

Every ip can execute a maximum number of requests per day, after that, it can't be used again till the next day; the time interval between two requests doesn't matter, as long as the daily limit is not reached.

I would like to configure the firewall's routing table so that, from the client machine, I can make http requests without worrying about the time interval between them. My only concern should be the total daily limit (i.e. number of ips * max requests per ip).

I tried something like:

iptables -m hashlimit -m tcp -A POSTROUTING --syn --hashlimit-name x --hashlimit <MAX REQUESTS>/day -p tcp -s <CLIENT IP> -d <SERVER IP> --dports 80 --to-source <ONE OF THE IPs TO CHOOSE FROM>

And repeated that command for all of the five ips (with a final rule that drops further connection attempts).

But with this configuration I can't do requests in bursts. For example, if MAX_REQUESTS is 9000, i cannot make 9000 requests in the first two minutes, because the hashlimit module deals with averages, and stops matching a rule as soon as the packets' count is above the specified average. Therefore with this configuration I can use that ip only once every 9.6 seconds (=86400/9000): not what I want.

So I'm asking for suggestions about a possible iptables rule (or something else) which would allow me to perform requests in bursts and stay within the daily limit.

Thanks for your time

Silvio

EDIT: I have tried using --hashlimit-burst N, but this parameter only inserts a tolerance for the first N packets, i.e. adds N packets which can match the rule regardless of the average, after which the normal conditions apply. Again, not what I want.

UPDATE: The current candidate iptable command I'm using is

iptables -m hashlimit -m multiport -m tcp -A POSTROUTING -t nat --syn --hashlimit-name NAME --hashlimit MAX_REQUEST/day -p tcp -s SOURCE_IP -d DESTINATION_IP --dports 80 -j SNAT --to-source ONE_OF_THE IPs

It still has the above mentioned problem (can't send packets in bursts).

I recently compiled a PHP 5.2.9 binary, and I tried to execute some PHP scripts with it. I can execute some scripts without problems, but one of them halts its execution midway, exiting with no errors or warnings. The returned status code of the process is 255.

I've read in the manual that such status is 'reserved'. The question is: for what?

I believe it's got something to do with missing dependencies in the PHP executable, but I can't be sure.

Anyone knows what does an exit code of 255 mean?

P.S. There are no errors in the PHP scripts, they run OK on other machines.

My java application can sometimes be killed by an external script. This can be done either with SIGTERM or with SIGKILL.

The application is a server which receives many connections per second, and it can be killed while trying to serve them.

I would like to restart the application whenever it's killed, so I have prepared a script for that purpose.

The problem is that, once the app has been killed, the new application instance can't bind to the port used by the previous instance, because the "Address is already in use". The previous instance's process has been definitely terminated, anyway the offending listening port is still there, but it is assigned to bash (or sh on other machines).

Obviouly, my goal is to restart the application and let it bind successfully to the previous address.

I've tried waiting more than 200 seconds before restarting to no avail, anyway I can't afford to wait that much.

I've encountered this problem on all the machines I've ran the application (which is a jetty server with java 1.6).

Any suggestion is appreciated, thanks,

Silvio

EDIT Killing the jvm process is not the normal way I exit my application, this is used in case of problems (OutOfMemoryErrors) only. And I never need to kill it with SIGKILL, because SIGTERM always suffices, I resort to SIGKILL only in case SIGTERM fails, which has never happened. I'm working on a long term solution, meanwhile I have to keep my app running by applying stitches here and there.

EDIT To be more clear: this is the netstat -tunap | grep line I see before killing the process:

tcp6       0      0 :::8898       :::*        LISTEN      22709/java

and this is after killing the process

tcp6       0      0 :::8898       :::*        LISTEN      23665/sh

notice that the process with PID 22709 is killed and gone, but the port is still there (but locked by sh)

UPDATE after I kill my application, with netstat I can see a long list of pending connections in CLOSE_WAIT state, with my ip as destination. Also, I can see a sh process in state LISTEN listening on my port: when I kill it, a sleep process replaces it and listens on the same port: When I finally kill this sleep process, the port is released and I can restart successfully my server. That could be a solution to get my port released, but I fear that automatically killing processes in order to release a port is a bit risky