[PATCH v2 2/4] usertools: add option to change mount point owner

[Bruce Richardson]

On Fri, Jun 17, 2022 at 02:25:06PM +0300, Dmitry Kozlyuk wrote:
> Per mount(8), the previous owner and mode of the mount point
> become invisible as long as this filesystem remains mounted.
> Because dpdk-hugepages.py must be run as root,
> the new owner would be root.
> This is undesirable if the hugepage directory is being set up
> by the administrator for an unprivileged user.
> HugeTLB filesystem has options to set the mount point owner.
> Add --owner/-o option to apply this option when mounting.
> The benefit of performing this in dpdk-hugepages.py
> is that the user does not need to care about this detail
> of mount command operation.
> 
> Signed-off-by: Dmitry Kozlyuk <dkozlyuk at nvidia.com>
> ---
>  usertools/dpdk-hugepages.py | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/usertools/dpdk-hugepages.py b/usertools/dpdk-hugepages.py
> index 8bab086a2f..5120518bcb 100755
> --- a/usertools/dpdk-hugepages.py
> +++ b/usertools/dpdk-hugepages.py
> @@ -170,7 +170,7 @@ def get_mountpoints():
>      return mounted
>  
>  
> -def mount_huge(pagesize, mountpoint):
> +def mount_huge(pagesize, mountpoint, owner):
>      '''Mount the huge TLB file system'''
>      if mountpoint in get_mountpoints():
>          print(mountpoint, "already mounted")
> @@ -178,6 +178,9 @@ def mount_huge(pagesize, mountpoint):
>      cmd = "mount -t hugetlbfs"
>      if pagesize:
>          cmd += ' -o pagesize={}'.format(pagesize * 1024)
> +    if owner:
> +        uid, gid = owner.split(':', maxsplit=1)
> +        cmd += ' -o uid={},gid={}'.format(uid, gid)

I'm not sure about forcing the user to always provide a "user:group" format
parameter. How about:

1. checking initially for the presence of a ":" and if not present just
   working with the uid parameter?
2. alternatively, what about adding in separate parameters for user or
   group, so they can be specified independently?

/Bruce