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*SOLVED* getcwd dows not work on vps after chroot [message #4760]

Tue, 25 July 2006 17:54

disaster
Messages: 158
Registered: February 2006

Senior Member

Hello!

I've a little C Script which works perfectly with Kernel from 2.4 - 2.6.17.x on every normal system.

On a VPS getcwd returns always NULL.

Here is some code - like the script works:

chroot("/home");

getcwd(cwd, MAX_LENGTH);

on the a normal hardware server getcwd works correkt - on a VPS (same installation / same image) it always returns NULL and cwd is empty.

Stefan

[Updated on: Wed, 26 July 2006 20:07] by Moderator

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Re: getcwd dows not work on vps after chroot [message #4768 is a reply to message #4760]

Wed, 26 July 2006 06:13

Vasily Tarasov
Messages: 1345
Registered: January 2006

Senior Member

1. To use chroot inside VPS you must grant this capability to VE:

vzctl set 200 --capability sys_chroot:on --save

2. However your "testcase" doesn't work even on the host node.
So it seems to be a bug. I've posted it in bugzilla:
http://bugzilla.openvz.org/show_bug.cgi?id=209
Thanks for report!

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Re: getcwd dows not work on vps after chroot [message #4777 is a reply to message #4760]

Wed, 26 July 2006 07:44

disaster
Messages: 158
Registered: February 2006

Senior Member

Hi!

I stopped the VPS, turned sys_chroot on and started the vps again. But the Script still does not work.

It works perfectly if i do:

chroot("/home");
chdir("/ABC");
getcwd(cwd, MAX_LENGTH);

but without chdir it does not work on a VPS.

So thanks for the bug report.

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Re: getcwd dows not work on vps after chroot [message #4797 is a reply to message #4777]

Wed, 26 July 2006 14:09

Vasily Tarasov
Messages: 1345
Registered: January 2006

Senior Member

This isn't a bug.
In OpenVZ such scenario is deliberately prohibited for security
reasons: isolation of VEs.
This is rather mainstream BUG and the decent patch will be sent to kernel.org soon.
One more thing is that such scenario is questionable: you don't get consistent information from getcwd after chroot.

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