C++ application collapsing after some hours

问题:

i have an application written in C++ that uses opencv 2.0, curl and a opensurf library. First a PHP script (cron.php) calls proc_open and calls the C++ application (called icomparer). When it finishes processing N images returns groups saying which images are the same, after that the script uses:

shell_exec('php cron.php > /dev/null 2>&1 &');  
die;

And starts again. Well, after 800 or 900 iterates my icomparer starts breaking. The system don't lets me create more files, in icomparer and in the php script.

proc_open(): unable to create pipe Too many open files (2)
shell_exec(): Unable to execute 'php cron.php > /dev/null 2>&1 &'

And curl fails too:

couldn't resolve host name (6)

Everything crashes. I think that i'm doing something wrong, for example, I dunno if starting another PHP process from a PHP process release resources.

In "icomparer" I'm closing all opened files. Maybe not releasing all mutex with mutex_destroy... but in each iterator the c++ application is closed, I think that all stuff is released right?

What I have to watch for? I have tried monitoring opened files with stof.

---

• Php 5.2
• Centos 5.X
• 1 GB ram
• 120 gb hard disk (4% used)
• 4 x intel xeon
• Is a VPS (machine has 16 gb ram)
• The process opens 10 threads and joins them.

回答1:

On Unix-alike systems, child processes inherit the open file descriptors of the parent. However, when the child process exits, it does close all of its copies of the open file descriptors but not the parent's copies.

So you are opening file descriptors in the parent and not closing them. My bet is that you are not closing the pipes returned by the proc_open() call.

And you'll also need to call proc_close() too.

回答2:

Sounds like you're leaking file descriptors.

回答3:

Yeah, it looks like you're opening processes but don't close them after use and - as it seems - they are not closed automatically (which may work in some circumstances).

Make sure you close/terminate your process with proc_close($res) if you don't use the resource anymore.

回答4:

Your application doesn't close it's files / sockets you can try to use the ulimit syscall with this you can remove the number of open files allowed per application. Have a look: man ulimit