`listmount` and `statmount`

[rusty-snake]

Issue for addition of listmount and statmount and related ioctls.

• https://www.man7.org/linux/man-pages/man2/listmount.2.html
• https://www.man7.org/linux/man-pages/man2/statmount.2.html
• https://brauner.io/2024/12/16/list-all-mounts.html

Note that these syscalls see heavy development and the manpages are likely to be already out of date.

• [ ] listmount
• [ ] statmount
• [ ] ioctl_ns_mnt_get_info, ioctl_ns_mnt_get_next, ioctl_ns_mnt_get_prev
  • [ ] struct mnt_ns_info
• [ ] ioctl_ns_get_mntns_id

cc @yujincheng08