This will solve the problem of mounts for VMs being very annoying to clean up, as evidenced in run-appimage. It was looking to be even worse for Flatpak. Signed-off-by: Alyssa Ross <hi@alyssa.is> --- v2: Fix spectrum-update by unsharing with slave propagation instead of private and entering the namespace before setting up mounts. v1: https://spectrum-os.org/lists/archives/spectrum-devel/20251201044534.977524-... .../template/data/service/dbus/run | 2 ++ .../template/data/service/vhost-user-fs/run | 6 +---- .../image/usr/bin/create-vm-dependencies | 26 ++++++++++++++++--- host/rootfs/image/usr/bin/run-appimage | 25 +++++++++--------- host/rootfs/image/usr/bin/spectrum-update | 3 +++ 5 files changed, 40 insertions(+), 22 deletions(-) diff --git a/host/rootfs/image/etc/s6-linux-init/run-image/service/vm-services/template/data/service/dbus/run b/host/rootfs/image/etc/s6-linux-init/run-image/service/vm-services/template/data/service/dbus/run index 351fc68..9b23192 100755 --- a/host/rootfs/image/etc/s6-linux-init/run-image/service/vm-services/template/data/service/dbus/run +++ b/host/rootfs/image/etc/s6-linux-init/run-image/service/vm-services/template/data/service/dbus/run @@ -4,6 +4,8 @@ importas -i VM VM +nsenter --mount=${VM}/mount + dbus-daemon --config-file /usr/share/dbus-1/session.conf --print-address 3 diff --git a/host/rootfs/image/etc/s6-linux-init/run-image/service/vm-services/template/data/service/vhost-user-fs/run b/host/rootfs/image/etc/s6-linux-init/run-image/service/vm-services/template/data/service/vhost-user-fs/run index 5d5ad7d..a9bbd8e 100755 --- a/host/rootfs/image/etc/s6-linux-init/run-image/service/vm-services/template/data/service/vhost-user-fs/run +++ b/host/rootfs/image/etc/s6-linux-init/run-image/service/vm-services/template/data/service/vhost-user-fs/run @@ -10,10 +10,6 @@ redirfd -r 0 /dev/null export TMPDIR /run -# The VM should not be able to write directly into a tmpfs, but there -# can be writable block-based bind mounted subdirectories. -unshare -m --propagation slave importas -i VM VM -if { mount --rbind -o ro ${VM}/fs ${VM}/fs } - +nsenter --mount=${VM}/mount virtiofsd --fd 3 --shared-dir ${VM}/fs diff --git a/host/rootfs/image/usr/bin/create-vm-dependencies b/host/rootfs/image/usr/bin/create-vm-dependencies index f3a1b69..8fb9f3a 100755 --- a/host/rootfs/image/usr/bin/create-vm-dependencies +++ b/host/rootfs/image/usr/bin/create-vm-dependencies @@ -1,11 +1,29 @@ #!/bin/execlineb -S1 # SPDX-License-Identifier: EUPL-1.2+ -# SPDX-FileCopyrightText: 2024 Alyssa Ross <hi@alyssa.is> +# SPDX-FileCopyrightText: 2024-2025 Alyssa Ross <hi@alyssa.is> -if { mount -m --rbind -o nofail /run/vm/by-id/${1}/config/fs /run/vm/by-id/${1}/fs/config } +if { touch /run/vm/by-id/${1}/mount } +if { mount --make-private --bind /run/vm/by-id/${1}/mount /run/vm/by-id/${1}/mount } -if { mkdir -p /run/vm/by-id/${1}/doc-run/doc /run/vm/by-id/${1}/fs/doc } -if { mount --rbind /run/vm/by-id/${1}/doc-run/doc /run/vm/by-id/${1}/fs/doc } +if { + unshare --propagation=slave --mount=/run/vm/by-id/${1}/mount + + if { + mkdir -p + /run/vm/by-id/${1}/doc-run/doc + /run/vm/by-id/${1}/fs/config + /run/vm/by-id/${1}/fs/doc + } + + if { mount --make-shared --rbind /run/vm/by-id/${1} /run/vm/by-id/${1} } + + # The VM should not be able to write directly into a tmpfs, and the host + # should be able to assume there are no untrusted symlinks there, but there + # can be writable block-based bind mounted subdirectories. + if { mount --rbind -o nofail /run/vm/by-id/${1}/config/fs /run/vm/by-id/${1}/fs/config } + if { mount --rbind -o ro /run/vm/by-id/${1}/fs /run/vm/by-id/${1}/fs } + mount --rbind /run/vm/by-id/${1}/doc-run/doc /run/vm/by-id/${1}/fs/doc +} if { s6-instance-create /run/service/vm-services $1 } elglob -0 services /run/service/vm-services/instance/${1}/services/* diff --git a/host/rootfs/image/usr/bin/run-appimage b/host/rootfs/image/usr/bin/run-appimage index 6ccc61f..f2fe7bc 100755 --- a/host/rootfs/image/usr/bin/run-appimage +++ b/host/rootfs/image/usr/bin/run-appimage @@ -1,14 +1,12 @@ #!/bin/execlineb -S1 # SPDX-License-Identifier: EUPL-1.2+ -# SPDX-FileCopyrightText: 2024 Alyssa Ross <hi@alyssa.is> +# SPDX-FileCopyrightText: 2024-2025 Alyssa Ross <hi@alyssa.is> backtick -E dir { mktemp -d /run/vm/by-id/XXXXXX } backtick -E id { basename -- $dir } if { mkdir -p /run/configs/${id}/fs } -if { redirfd -w 1 /run/configs/${id}/fs/type echo appimage } -if { touch /run/configs/${id}/fs/run } -if { mount --rbind $1 /run/configs/${id}/fs/run } + if { ln -s /usr/lib/spectrum/img/appvm/blk /usr/lib/spectrum/img/appvm/vmlinux /run/configs/${id} @@ -18,6 +16,14 @@ if { ln -s /run/configs/${id} ${dir}/config } if { create-vm-dependencies $id } +if { + nsenter --mount=${dir}/mount + cd ${dir}/fs/config + if { redirfd -w 1 type echo appimage } + if { touch run } + mount --bind $1 run +} + piperw 4 3 background { fdclose 3 @@ -34,13 +40,6 @@ fdclose 3 if { s6-instance-delete /run/service/vm-services $id } -if { - forx -E mount { - /run/configs/${id}/fs/run - ${dir}/fs/config - ${dir}/fs/doc - } - umount $mount -} - +if { umount ${dir}/mount } # mount namespace +if { umount ${dir}/mount } # private bind mount rm -r $dir /run/configs/${id} diff --git a/host/rootfs/image/usr/bin/spectrum-update b/host/rootfs/image/usr/bin/spectrum-update index bf5b0b0..b1517a6 100755 --- a/host/rootfs/image/usr/bin/spectrum-update +++ b/host/rootfs/image/usr/bin/spectrum-update @@ -50,6 +50,9 @@ foreground { cp -- /etc/systemd/import-pubring.gpg /run/vm/by-id/${update_vm_id}/fs/etc/systemd } + nsenter --mount=/run/vm/by-id/${update_vm_id}/mount + cd $1 + # If the directory is already mounted, unmount it. This prevents a # confusing error from mount. foreground { redirfd -w 2 /dev/null umount -- /run/vm/by-id/${update_vm_id}/fs/updates } -- 2.51.0