Linked Questions

24
votes
2answers
11k views

per process private file system mount points

I was checking unshare command and according to it's man page, unshare - run program with some namespaces unshared from parent I also see there is a type of namespace listed as, mount namespace ...
13
votes
2answers
4k views

Simulate chroot with unshare

I am trying to write a bootstrapper for a minimal, from-source linux distribution. I would like to build in a chroot-like environment. This should simplify packaging. I do not care about security at ...
3
votes
1answer
1k views

Why is there no rootfs file system present on my system?

The linux kernel documentation claims: Rootfs is a special instance of ramfs (or tmpfs, if that's enabled), which is always present in 2.6 systems. You can't unmount rootfs … On all linux ...
1
vote
1answer
1k views

Understanding how mount namespaces work in Linux

I am reading about mount namespaces and see: in a mount namespace you can mount and unmount filesystems without it affecting the host filesystem. So you can have a totally different set of devices ...
1
vote
2answers
290 views

How to create a chroot from which root cannot escape using chdir(“..”) on Linux, inside a filesystem?

I have a directory /var/mychoot on the same filesystem as /, and I've started the program /var/mychroot/prog as sudo chroot /var/mychroot /prog, so the program is running as EUID 0. If the program ...
0
votes
1answer
319 views

chroot before pivot_root causes busy error

# unshare -m # mount --bind / /mnt # cd /mnt # chroot . # pivot_root . mnt pivot_root: failed to change root from `.' to `mnt': Device or resource busy Why does it fail? I was following the ...
1
vote
1answer
298 views

I don't understand how entering a mount namespace can work

either if you fork into a new mount namespace, or enter an existing one. It is possible to hold file descriptors from a foreign mount namespace. You can demonstrate this very easily, by finding a ...
0
votes
1answer
171 views

`umount -R` on bind mounts takes a non-neglible amount of time, why?

Why does umount -R take 0.2s to unmount this subtree of bind mounts? It only took 0.02s to mount the subtree, and 0.00s to change its propagation flags. (I was looking at cloning the current set of ...
0
votes
1answer
39 views

pivot_root(2) causes system crash

I am trying to change the root of my process to new file system that I mounted at /tmp/mount_dir and i have created another directory inside it /tmp/mount_dir/inner_mount_dir, and according to the man ...
-1
votes
1answer
42 views

Does chroot need any special kernel support?

docker is said to be a steroid version of chroot. Does chroot need any special kernel support, e.g. namespace, cgroup? Does docker rely on chroot? I ask this because "Docker is not virtualisation: ...