[v3,2/5] usertools: add option to change mount point owner

Message ID 20220624084817.63145-3-dkozlyuk@nvidia.com (mailing list archive)
State Superseded, archived
Delegated to: Thomas Monjalon
Headers
Series Improve documentation for running as non-root |

Checks

Context Check Description
ci/checkpatch success coding style OK

Commit Message

Dmitry Kozlyuk June 24, 2022, 8:48 a.m. UTC
  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@nvidia.com>
---
 usertools/dpdk-hugepages.py | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)
  

Comments

Bruce Richardson June 24, 2022, 9:04 a.m. UTC | #1
On Fri, Jun 24, 2022 at 11:48:14AM +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@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)

Still don't like this syntax and always setting both together. Can we
change the "owner" flag to separate "uid" and "gid" flags so they can be
set independently (and explicitly).

/Bruce
  

Patch

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)
     cmd += ' nodev ' + mountpoint
     os.system(cmd)
 
@@ -234,6 +237,11 @@  def main():
         metavar='DIR',
         default=HUGE_MOUNT,
         help='mount point')
+    parser.add_argument(
+        '--owner',
+        '-o',
+        metavar='USER:GROUP',
+        help='change the mounted directory owner')
     parser.add_argument(
         '--node', '-n', help='select numa node to reserve pages on')
     parser.add_argument(
@@ -279,7 +287,7 @@  def main():
         reserve_pages(
             int(reserve_kb / pagesize_kb), pagesize_kb, node=args.node)
     if args.mount:
-        mount_huge(pagesize_kb, args.directory)
+        mount_huge(pagesize_kb, args.directory, args.owner)
     if args.show:
         show_pages()
         print()