hardware acceleration and support for NVIDIA cards on nonfree images (#3089)

* add nvidia packages

* add nvidia deps to nonfree

* gpu_acceleration flag & nvidia hacking

* fix gpu_config & /tmp/lxc.log

* implement hardware acceleration more dynamically

* refactor OpenUI

* use mknod

* registry updates for multi-hardware-requirements

* pluralize

* handle new registry types

* remove log

* migrations and driver fixes

* wip

* misc patches

* handle nvidia-container differently

* chore: comments (#3093)

* chore: comments

* revert some sizing

---------

Co-authored-by: Matt Hill <mattnine@protonmail.com>

* Revert "handle nvidia-container differently"

This reverts commit d708ae53df.

* fix debian containers

* cleanup

* feat: add empty array placeholder in forms (#3095)

* fixes from testing, client side device filtering for better fingerprinting resistance

* fix mac builds

---------

Co-authored-by: Sam Sartor <me@samsartor.com>
Co-authored-by: Matt Hill <mattnine@protonmail.com>
Co-authored-by: Alex Inkin <alexander@inkin.ru>

core/src/disk/mount/util.rs

@@ -3,6 +3,7 @@ use std::path::Path;
 use tracing::instrument;
 
 use crate::Error;
+use crate::prelude::*;
 use crate::util::Invoke;
 
 pub async fn is_mountpoint(path: impl AsRef<Path>) -> Result<bool, Error> {
@@ -56,3 +57,42 @@ pub async fn unmount<P: AsRef<Path>>(mountpoint: P, lazy: bool) -> Result<(), Er
         .await?;
     Ok(())
 }
+
+/// Unmounts all mountpoints under (and including) the given path, in reverse
+/// depth order so that nested mounts are unmounted before their parents.
+#[instrument(skip_all)]
+pub async fn unmount_all_under<P: AsRef<Path>>(path: P, lazy: bool) -> Result<(), Error> {
+    let path = path.as_ref();
+    let canonical_path = tokio::fs::canonicalize(path)
+        .await
+        .with_ctx(|_| (ErrorKind::Filesystem, lazy_format!("canonicalize {path:?}")))?;
+
+    let mounts_content = tokio::fs::read_to_string("/proc/mounts")
+        .await
+        .with_ctx(|_| (ErrorKind::Filesystem, "read /proc/mounts"))?;
+
+    // Collect all mountpoints under our path
+    let mut mountpoints: Vec<&str> = mounts_content
+        .lines()
+        .filter_map(|line| {
+            let mountpoint = line.split_whitespace().nth(1)?;
+            // Check if this mountpoint is under our target path
+            let mp_path = Path::new(mountpoint);
+            if mp_path.starts_with(&canonical_path) {
+                Some(mountpoint)
+            } else {
+                None
+            }
+        })
+        .collect();
+
+    // Sort by path length descending so we unmount deepest first
+    mountpoints.sort_by(|a, b| b.len().cmp(&a.len()));
+
+    for mountpoint in mountpoints {
+        tracing::debug!("Unmounting nested mountpoint: {}", mountpoint);
+        unmount(mountpoint, lazy).await?;
+    }
+
+    Ok(())
+}