* [PATCH 1/5] img/app: install fuse3 globally
@ 2025-12-01 4:45 Alyssa Ross
2025-12-01 4:45 ` [PATCH 2/5] host/rootfs: create a per-VM mount namespace Alyssa Ross
` (3 more replies)
0 siblings, 4 replies; 11+ messages in thread
From: Alyssa Ross @ 2025-12-01 4:45 UTC (permalink / raw)
To: devel; +Cc: Demi Marie Obenour
AppImage (and in-development Flatpak) VMs complain about this being
absent and portals don't work without it, even though Nix VMs work
fine. I suppose it's a packaging difference.
Signed-off-by: Alyssa Ross <hi@alyssa.is>
---
img/app/default.nix | 1 +
1 file changed, 1 insertion(+)
diff --git a/img/app/default.nix b/img/app/default.nix
index 6490ac2..1eb3c9b 100644
--- a/img/app/default.nix
+++ b/img/app/default.nix
@@ -65,6 +65,7 @@ let
pkgs.cacert
pkgs.dejavu_fonts
pkgs.execline
+ pkgs.fuse3
pkgs.kmod
pkgs.mdevd
pkgs.pipewire
base-commit: cf131bd816a34095af34345f0e5f148c47268a04
--
2.51.0
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH 2/5] host/rootfs: create a per-VM mount namespace
2025-12-01 4:45 [PATCH 1/5] img/app: install fuse3 globally Alyssa Ross
@ 2025-12-01 4:45 ` Alyssa Ross
2025-12-01 4:52 ` Demi Marie Obenour
2025-12-01 4:45 ` [PATCH v4 3/5] tools/mount-flatpak: init Alyssa Ross
` (2 subsequent siblings)
3 siblings, 1 reply; 11+ messages in thread
From: Alyssa Ross @ 2025-12-01 4:45 UTC (permalink / raw)
To: devel; +Cc: Demi Marie Obenour
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>
---
.../template/data/service/dbus/run | 2 ++
.../template/data/service/vhost-user-fs/run | 4 +--
.../image/usr/bin/create-vm-dependencies | 23 ++++++++++++++---
host/rootfs/image/usr/bin/run-appimage | 25 +++++++++----------
4 files changed, 34 insertions(+), 20 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..3848b0c 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
@@ -12,8 +12,6 @@ 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 ${VM}/fs
diff --git a/host/rootfs/image/usr/bin/create-vm-dependencies b/host/rootfs/image/usr/bin/create-vm-dependencies
index f3a1b69..21681cd 100755
--- a/host/rootfs/image/usr/bin/create-vm-dependencies
+++ b/host/rootfs/image/usr/bin/create-vm-dependencies
@@ -1,11 +1,26 @@
#!/bin/execlineb -S1
# SPDX-License-Identifier: EUPL-1.2+
-# SPDX-FileCopyrightText: 2024 Alyssa Ross <hi@alyssa.is>
+# SPDX-FileCopyrightText: 2024-2025 Alyssa Ross <hi@alyssa.is>
-if { mount -m --rbind -o nofail /run/vm/by-id/${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 --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} }
+
+ if { mount --rbind -o ro /run/vm/by-id/${1}/fs /run/vm/by-id/${1}/fs }
+ if { mount --rbind -o nofail /run/vm/by-id/${1}/config/fs /run/vm/by-id/${1}/fs/config }
+ 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}
--
2.51.0
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH v4 3/5] tools/mount-flatpak: init
2025-12-01 4:45 [PATCH 1/5] img/app: install fuse3 globally Alyssa Ross
2025-12-01 4:45 ` [PATCH 2/5] host/rootfs: create a per-VM mount namespace Alyssa Ross
@ 2025-12-01 4:45 ` Alyssa Ross
2025-12-01 5:14 ` Demi Marie Obenour
2025-12-01 4:45 ` [PATCH v4 4/5] img/app: run Flatpak applications Alyssa Ross
2025-12-01 4:45 ` [PATCH v4 5/5] host/rootfs: add run-flatpak script Alyssa Ross
3 siblings, 1 reply; 11+ messages in thread
From: Alyssa Ross @ 2025-12-01 4:45 UTC (permalink / raw)
To: devel; +Cc: Demi Marie Obenour
I tried to build this with Meson, but pathrs depends on thiserror,
which tries to read OUT_DIR, and support for setting that isn't
currently in a Meson release, and requires nightly Rust, so build with
Cargo for now and we can revisit that later.
Link: https://github.com/mesonbuild/meson/pull/15148
Link: https://github.com/rust-lang/rust/issues/118372
Signed-off-by: Alyssa Ross <hi@alyssa.is>
---
v4: • Open a root for the Flatpak installation to limit scope
• Update usage
• Call open_tree with AT_SYMLINK_NOFOLLOW
• Add comment explaining purpose and directory structure
• Set MS_SLAVE on the final mount
• Cast non-pointer syscall arguments to long
v3: https://spectrum-os.org/lists/archives/spectrum-devel/20251127202311.42422-2-hi@alyssa.is/
LICENSES/MPL-2.0.txt | 373 +++++++++++++++++++++++++
pkgs/default.nix | 1 +
tools/mount-flatpak/Cargo.lock | 238 ++++++++++++++++
tools/mount-flatpak/Cargo.lock.license | 2 +
tools/mount-flatpak/Cargo.toml | 11 +
tools/mount-flatpak/config | 7 +
tools/mount-flatpak/default.nix | 25 ++
tools/mount-flatpak/src/keyfile.rs | 189 +++++++++++++
tools/mount-flatpak/src/main.rs | 296 ++++++++++++++++++++
tools/mount-flatpak/src/metadata.rs | 19 ++
10 files changed, 1161 insertions(+)
create mode 100644 LICENSES/MPL-2.0.txt
create mode 100644 tools/mount-flatpak/Cargo.lock
create mode 100644 tools/mount-flatpak/Cargo.lock.license
create mode 100644 tools/mount-flatpak/Cargo.toml
create mode 100644 tools/mount-flatpak/config
create mode 100644 tools/mount-flatpak/default.nix
create mode 100644 tools/mount-flatpak/src/keyfile.rs
create mode 100644 tools/mount-flatpak/src/main.rs
create mode 100644 tools/mount-flatpak/src/metadata.rs
diff --git a/LICENSES/MPL-2.0.txt b/LICENSES/MPL-2.0.txt
new file mode 100644
index 0000000..d0a1fa1
--- /dev/null
+++ b/LICENSES/MPL-2.0.txt
@@ -0,0 +1,373 @@
+Mozilla Public License Version 2.0
+==================================
+
+1. Definitions
+--------------
+
+1.1. "Contributor"
+ means each individual or legal entity that creates, contributes to
+ the creation of, or owns Covered Software.
+
+1.2. "Contributor Version"
+ means the combination of the Contributions of others (if any) used
+ by a Contributor and that particular Contributor's Contribution.
+
+1.3. "Contribution"
+ means Covered Software of a particular Contributor.
+
+1.4. "Covered Software"
+ means Source Code Form to which the initial Contributor has attached
+ the notice in Exhibit A, the Executable Form of such Source Code
+ Form, and Modifications of such Source Code Form, in each case
+ including portions thereof.
+
+1.5. "Incompatible With Secondary Licenses"
+ means
+
+ (a) that the initial Contributor has attached the notice described
+ in Exhibit B to the Covered Software; or
+
+ (b) that the Covered Software was made available under the terms of
+ version 1.1 or earlier of the License, but not also under the
+ terms of a Secondary License.
+
+1.6. "Executable Form"
+ means any form of the work other than Source Code Form.
+
+1.7. "Larger Work"
+ means a work that combines Covered Software with other material, in
+ a separate file or files, that is not Covered Software.
+
+1.8. "License"
+ means this document.
+
+1.9. "Licensable"
+ means having the right to grant, to the maximum extent possible,
+ whether at the time of the initial grant or subsequently, any and
+ all of the rights conveyed by this License.
+
+1.10. "Modifications"
+ means any of the following:
+
+ (a) any file in Source Code Form that results from an addition to,
+ deletion from, or modification of the contents of Covered
+ Software; or
+
+ (b) any new file in Source Code Form that contains any Covered
+ Software.
+
+1.11. "Patent Claims" of a Contributor
+ means any patent claim(s), including without limitation, method,
+ process, and apparatus claims, in any patent Licensable by such
+ Contributor that would be infringed, but for the grant of the
+ License, by the making, using, selling, offering for sale, having
+ made, import, or transfer of either its Contributions or its
+ Contributor Version.
+
+1.12. "Secondary License"
+ means either the GNU General Public License, Version 2.0, the GNU
+ Lesser General Public License, Version 2.1, the GNU Affero General
+ Public License, Version 3.0, or any later versions of those
+ licenses.
+
+1.13. "Source Code Form"
+ means the form of the work preferred for making modifications.
+
+1.14. "You" (or "Your")
+ means an individual or a legal entity exercising rights under this
+ License. For legal entities, "You" includes any entity that
+ controls, is controlled by, or is under common control with You. For
+ purposes of this definition, "control" means (a) the power, direct
+ or indirect, to cause the direction or management of such entity,
+ whether by contract or otherwise, or (b) ownership of more than
+ fifty percent (50%) of the outstanding shares or beneficial
+ ownership of such entity.
+
+2. License Grants and Conditions
+--------------------------------
+
+2.1. Grants
+
+Each Contributor hereby grants You a world-wide, royalty-free,
+non-exclusive license:
+
+(a) under intellectual property rights (other than patent or trademark)
+ Licensable by such Contributor to use, reproduce, make available,
+ modify, display, perform, distribute, and otherwise exploit its
+ Contributions, either on an unmodified basis, with Modifications, or
+ as part of a Larger Work; and
+
+(b) under Patent Claims of such Contributor to make, use, sell, offer
+ for sale, have made, import, and otherwise transfer either its
+ Contributions or its Contributor Version.
+
+2.2. Effective Date
+
+The licenses granted in Section 2.1 with respect to any Contribution
+become effective for each Contribution on the date the Contributor first
+distributes such Contribution.
+
+2.3. Limitations on Grant Scope
+
+The licenses granted in this Section 2 are the only rights granted under
+this License. No additional rights or licenses will be implied from the
+distribution or licensing of Covered Software under this License.
+Notwithstanding Section 2.1(b) above, no patent license is granted by a
+Contributor:
+
+(a) for any code that a Contributor has removed from Covered Software;
+ or
+
+(b) for infringements caused by: (i) Your and any other third party's
+ modifications of Covered Software, or (ii) the combination of its
+ Contributions with other software (except as part of its Contributor
+ Version); or
+
+(c) under Patent Claims infringed by Covered Software in the absence of
+ its Contributions.
+
+This License does not grant any rights in the trademarks, service marks,
+or logos of any Contributor (except as may be necessary to comply with
+the notice requirements in Section 3.4).
+
+2.4. Subsequent Licenses
+
+No Contributor makes additional grants as a result of Your choice to
+distribute the Covered Software under a subsequent version of this
+License (see Section 10.2) or under the terms of a Secondary License (if
+permitted under the terms of Section 3.3).
+
+2.5. Representation
+
+Each Contributor represents that the Contributor believes its
+Contributions are its original creation(s) or it has sufficient rights
+to grant the rights to its Contributions conveyed by this License.
+
+2.6. Fair Use
+
+This License is not intended to limit any rights You have under
+applicable copyright doctrines of fair use, fair dealing, or other
+equivalents.
+
+2.7. Conditions
+
+Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted
+in Section 2.1.
+
+3. Responsibilities
+-------------------
+
+3.1. Distribution of Source Form
+
+All distribution of Covered Software in Source Code Form, including any
+Modifications that You create or to which You contribute, must be under
+the terms of this License. You must inform recipients that the Source
+Code Form of the Covered Software is governed by the terms of this
+License, and how they can obtain a copy of this License. You may not
+attempt to alter or restrict the recipients' rights in the Source Code
+Form.
+
+3.2. Distribution of Executable Form
+
+If You distribute Covered Software in Executable Form then:
+
+(a) such Covered Software must also be made available in Source Code
+ Form, as described in Section 3.1, and You must inform recipients of
+ the Executable Form how they can obtain a copy of such Source Code
+ Form by reasonable means in a timely manner, at a charge no more
+ than the cost of distribution to the recipient; and
+
+(b) You may distribute such Executable Form under the terms of this
+ License, or sublicense it under different terms, provided that the
+ license for the Executable Form does not attempt to limit or alter
+ the recipients' rights in the Source Code Form under this License.
+
+3.3. Distribution of a Larger Work
+
+You may create and distribute a Larger Work under terms of Your choice,
+provided that You also comply with the requirements of this License for
+the Covered Software. If the Larger Work is a combination of Covered
+Software with a work governed by one or more Secondary Licenses, and the
+Covered Software is not Incompatible With Secondary Licenses, this
+License permits You to additionally distribute such Covered Software
+under the terms of such Secondary License(s), so that the recipient of
+the Larger Work may, at their option, further distribute the Covered
+Software under the terms of either this License or such Secondary
+License(s).
+
+3.4. Notices
+
+You may not remove or alter the substance of any license notices
+(including copyright notices, patent notices, disclaimers of warranty,
+or limitations of liability) contained within the Source Code Form of
+the Covered Software, except that You may alter any license notices to
+the extent required to remedy known factual inaccuracies.
+
+3.5. Application of Additional Terms
+
+You may choose to offer, and to charge a fee for, warranty, support,
+indemnity or liability obligations to one or more recipients of Covered
+Software. However, You may do so only on Your own behalf, and not on
+behalf of any Contributor. You must make it absolutely clear that any
+such warranty, support, indemnity, or liability obligation is offered by
+You alone, and You hereby agree to indemnify every Contributor for any
+liability incurred by such Contributor as a result of warranty, support,
+indemnity or liability terms You offer. You may include additional
+disclaimers of warranty and limitations of liability specific to any
+jurisdiction.
+
+4. Inability to Comply Due to Statute or Regulation
+---------------------------------------------------
+
+If it is impossible for You to comply with any of the terms of this
+License with respect to some or all of the Covered Software due to
+statute, judicial order, or regulation then You must: (a) comply with
+the terms of this License to the maximum extent possible; and (b)
+describe the limitations and the code they affect. Such description must
+be placed in a text file included with all distributions of the Covered
+Software under this License. Except to the extent prohibited by statute
+or regulation, such description must be sufficiently detailed for a
+recipient of ordinary skill to be able to understand it.
+
+5. Termination
+--------------
+
+5.1. The rights granted under this License will terminate automatically
+if You fail to comply with any of its terms. However, if You become
+compliant, then the rights granted under this License from a particular
+Contributor are reinstated (a) provisionally, unless and until such
+Contributor explicitly and finally terminates Your grants, and (b) on an
+ongoing basis, if such Contributor fails to notify You of the
+non-compliance by some reasonable means prior to 60 days after You have
+come back into compliance. Moreover, Your grants from a particular
+Contributor are reinstated on an ongoing basis if such Contributor
+notifies You of the non-compliance by some reasonable means, this is the
+first time You have received notice of non-compliance with this License
+from such Contributor, and You become compliant prior to 30 days after
+Your receipt of the notice.
+
+5.2. If You initiate litigation against any entity by asserting a patent
+infringement claim (excluding declaratory judgment actions,
+counter-claims, and cross-claims) alleging that a Contributor Version
+directly or indirectly infringes any patent, then the rights granted to
+You by any and all Contributors for the Covered Software under Section
+2.1 of this License shall terminate.
+
+5.3. In the event of termination under Sections 5.1 or 5.2 above, all
+end user license agreements (excluding distributors and resellers) which
+have been validly granted by You or Your distributors under this License
+prior to termination shall survive termination.
+
+************************************************************************
+* *
+* 6. Disclaimer of Warranty *
+* ------------------------- *
+* *
+* Covered Software is provided under this License on an "as is" *
+* basis, without warranty of any kind, either expressed, implied, or *
+* statutory, including, without limitation, warranties that the *
+* Covered Software is free of defects, merchantable, fit for a *
+* particular purpose or non-infringing. The entire risk as to the *
+* quality and performance of the Covered Software is with You. *
+* Should any Covered Software prove defective in any respect, You *
+* (not any Contributor) assume the cost of any necessary servicing, *
+* repair, or correction. This disclaimer of warranty constitutes an *
+* essential part of this License. No use of any Covered Software is *
+* authorized under this License except under this disclaimer. *
+* *
+************************************************************************
+
+************************************************************************
+* *
+* 7. Limitation of Liability *
+* -------------------------- *
+* *
+* Under no circumstances and under no legal theory, whether tort *
+* (including negligence), contract, or otherwise, shall any *
+* Contributor, or anyone who distributes Covered Software as *
+* permitted above, be liable to You for any direct, indirect, *
+* special, incidental, or consequential damages of any character *
+* including, without limitation, damages for lost profits, loss of *
+* goodwill, work stoppage, computer failure or malfunction, or any *
+* and all other commercial damages or losses, even if such party *
+* shall have been informed of the possibility of such damages. This *
+* limitation of liability shall not apply to liability for death or *
+* personal injury resulting from such party's negligence to the *
+* extent applicable law prohibits such limitation. Some *
+* jurisdictions do not allow the exclusion or limitation of *
+* incidental or consequential damages, so this exclusion and *
+* limitation may not apply to You. *
+* *
+************************************************************************
+
+8. Litigation
+-------------
+
+Any litigation relating to this License may be brought only in the
+courts of a jurisdiction where the defendant maintains its principal
+place of business and such litigation shall be governed by laws of that
+jurisdiction, without reference to its conflict-of-law provisions.
+Nothing in this Section shall prevent a party's ability to bring
+cross-claims or counter-claims.
+
+9. Miscellaneous
+----------------
+
+This License represents the complete agreement concerning the subject
+matter hereof. If any provision of this License is held to be
+unenforceable, such provision shall be reformed only to the extent
+necessary to make it enforceable. Any law or regulation which provides
+that the language of a contract shall be construed against the drafter
+shall not be used to construe this License against a Contributor.
+
+10. Versions of the License
+---------------------------
+
+10.1. New Versions
+
+Mozilla Foundation is the license steward. Except as provided in Section
+10.3, no one other than the license steward has the right to modify or
+publish new versions of this License. Each version will be given a
+distinguishing version number.
+
+10.2. Effect of New Versions
+
+You may distribute the Covered Software under the terms of the version
+of the License under which You originally received the Covered Software,
+or under the terms of any subsequent version published by the license
+steward.
+
+10.3. Modified Versions
+
+If you create software not governed by this License, and you want to
+create a new license for such software, you may create and use a
+modified version of this License if you rename the license and remove
+any references to the name of the license steward (except to note that
+such modified license differs from this License).
+
+10.4. Distributing Source Code Form that is Incompatible With Secondary
+Licenses
+
+If You choose to distribute Source Code Form that is Incompatible With
+Secondary Licenses under the terms of this version of the License, the
+notice described in Exhibit B of this License must be attached.
+
+Exhibit A - Source Code Form License Notice
+-------------------------------------------
+
+ This Source Code Form is subject to the terms of the Mozilla Public
+ License, v. 2.0. If a copy of the MPL was not distributed with this
+ file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+If it is not possible or desirable to put the notice in a particular
+file, then You may include the notice in a location (such as a LICENSE
+file in a relevant directory) where a recipient would be likely to look
+for such a notice.
+
+You may add additional accurate notices of copyright ownership.
+
+Exhibit B - "Incompatible With Secondary Licenses" Notice
+---------------------------------------------------------
+
+ This Source Code Form is "Incompatible With Secondary Licenses", as
+ defined by the Mozilla Public License, v. 2.0.
diff --git a/pkgs/default.nix b/pkgs/default.nix
index bc25420..29fefb4 100644
--- a/pkgs/default.nix
+++ b/pkgs/default.nix
@@ -36,6 +36,7 @@ let
path: (import path { inherit (self) callPackage; }).override;
rootfs = self.callSpectrumPackage ../host/rootfs {};
+ mount-flatpak = self.callSpectrumPackage ../tools/mount-flatpak {};
spectrum-build-tools = self.callSpectrumPackage ../tools {
appSupport = false;
buildSupport = true;
diff --git a/tools/mount-flatpak/Cargo.lock b/tools/mount-flatpak/Cargo.lock
new file mode 100644
index 0000000..8cb5663
--- /dev/null
+++ b/tools/mount-flatpak/Cargo.lock
@@ -0,0 +1,238 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "bitflags"
+version = "2.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "812e12b5285cc515a9c72a5c1d3b6d46a19dac5acfef5265968c166106e31dd3"
+
+[[package]]
+name = "cfg-if"
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+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
+
+[[package]]
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+source = "registry+https://github.com/rust-lang/crates.io-index"
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+
+[[package]]
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+checksum = "39cab71617ae0d63f51a36d69f866391735b51691dbda63cf6f96d042b63efeb"
+dependencies = [
+ "libc",
+ "windows-sys",
+]
+
+[[package]]
+name = "fastrand"
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+source = "registry+https://github.com/rust-lang/crates.io-index"
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+
+[[package]]
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+dependencies = [
+ "cfg-if",
+ "libc",
+ "r-efi",
+ "wasip2",
+]
+
+[[package]]
+name = "itertools"
+version = "0.14.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2b192c782037fadd9cfa75548310488aabdbf3d2da73885b31bd0abd03351285"
+dependencies = [
+ "either",
+]
+
+[[package]]
+name = "libc"
+version = "0.2.177"
+source = "registry+https://github.com/rust-lang/crates.io-index"
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+
+[[package]]
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+source = "registry+https://github.com/rust-lang/crates.io-index"
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+
+[[package]]
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+
+[[package]]
+name = "mount-flatpak"
+version = "0.0.0"
+dependencies = [
+ "libc",
+ "pathrs",
+ "rustix",
+]
+
+[[package]]
+name = "once_cell"
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+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "42f5e15c9953c5e4ccceeb2e7382a716482c34515315f7b03532b8b4e8393d2d"
+
+[[package]]
+name = "pathrs"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c63f58f2463b3eecc7d285eace144d8c4820631d018d927049f8569be4b3b1a4"
+dependencies = [
+ "bitflags",
+ "itertools",
+ "libc",
+ "memchr",
+ "once_cell",
+ "rustix",
+ "rustversion",
+ "static_assertions",
+ "tempfile",
+ "thiserror",
+]
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.103"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5ee95bc4ef87b8d5ba32e8b7714ccc834865276eab0aed5c9958d00ec45f49e8"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.42"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a338cc41d27e6cc6dce6cefc13a0729dfbb81c262b1f519331575dd80ef3067f"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "r-efi"
+version = "5.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "69cdb34c158ceb288df11e18b4bd39de994f6657d83847bdffdbd7f346754b0f"
+
+[[package]]
+name = "rustix"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cd15f8a2c5551a84d56efdc1cd049089e409ac19a3072d5037a17fd70719ff3e"
+dependencies = [
+ "bitflags",
+ "errno",
+ "libc",
+ "linux-raw-sys",
+ "windows-sys",
+]
+
+[[package]]
+name = "rustversion"
+version = "1.0.22"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b39cdef0fa800fc44525c84ccb54a029961a8215f9619753635a9c0d2538d46d"
+
+[[package]]
+name = "static_assertions"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"
+
+[[package]]
+name = "syn"
+version = "2.0.111"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "390cc9a294ab71bdb1aa2e99d13be9c753cd2d7bd6560c77118597410c4d2e87"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
+[[package]]
+name = "tempfile"
+version = "3.23.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2d31c77bdf42a745371d260a26ca7163f1e0924b64afa0b688e61b5a9fa02f16"
+dependencies = [
+ "fastrand",
+ "getrandom",
+ "once_cell",
+ "rustix",
+ "windows-sys",
+]
+
+[[package]]
+name = "thiserror"
+version = "2.0.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f63587ca0f12b72a0600bcba1d40081f830876000bb46dd2337a3051618f4fc8"
+dependencies = [
+ "thiserror-impl",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "2.0.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3ff15c8ecd7de3849db632e14d18d2571fa09dfc5ed93479bc4485c7a517c913"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "unicode-ident"
+version = "1.0.22"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9312f7c4f6ff9069b165498234ce8be658059c6728633667c526e27dc2cf1df5"
+
+[[package]]
+name = "wasip2"
+version = "1.0.1+wasi-0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0562428422c63773dad2c345a1882263bbf4d65cf3f42e90921f787ef5ad58e7"
+dependencies = [
+ "wit-bindgen",
+]
+
+[[package]]
+name = "windows-link"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f0805222e57f7521d6a62e36fa9163bc891acd422f971defe97d64e70d0a4fe5"
+
+[[package]]
+name = "windows-sys"
+version = "0.61.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ae137229bcbd6cdf0f7b80a31df61766145077ddf49416a728b02cb3921ff3fc"
+dependencies = [
+ "windows-link",
+]
+
+[[package]]
+name = "wit-bindgen"
+version = "0.46.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f17a85883d4e6d00e8a97c586de764dabcc06133f7f1d55dce5cdc070ad7fe59"
diff --git a/tools/mount-flatpak/Cargo.lock.license b/tools/mount-flatpak/Cargo.lock.license
new file mode 100644
index 0000000..d705e97
--- /dev/null
+++ b/tools/mount-flatpak/Cargo.lock.license
@@ -0,0 +1,2 @@
+SPDX-License-Identifier: CC0-1.0
+SPDX-FileCopyrightText: 2024 Alyssa Ross <hi@alyssa.is>
diff --git a/tools/mount-flatpak/Cargo.toml b/tools/mount-flatpak/Cargo.toml
new file mode 100644
index 0000000..670be2f
--- /dev/null
+++ b/tools/mount-flatpak/Cargo.toml
@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: CC0-1.0
+# SPDX-FileCopyrightText: 2025 Alyssa Ross <hi@alyssa.is>
+
+[package]
+name = "mount-flatpak"
+edition = "2024"
+
+[dependencies]
+libc = "0.2.177"
+pathrs = "0.2.1"
+rustix = "1.1.2"
diff --git a/tools/mount-flatpak/config b/tools/mount-flatpak/config
new file mode 100644
index 0000000..b3c2bee
--- /dev/null
+++ b/tools/mount-flatpak/config
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: CC0-1.0
+# SPDX-FileCopyrightText: 2025 Alyssa Ross <hi@alyssa.is>
+
+[core]
+repo_version=1
+mode=bare-user-only
+min-free-space-size=500MB
diff --git a/tools/mount-flatpak/default.nix b/tools/mount-flatpak/default.nix
new file mode 100644
index 0000000..f364fd7
--- /dev/null
+++ b/tools/mount-flatpak/default.nix
@@ -0,0 +1,25 @@
+# SPDX-FileCopyrightText: 2024-2025 Alyssa Ross <hi@alyssa.is>
+# SPDX-License-Identifier: MIT
+
+import ../../lib/call-package.nix (
+{ src, lib, rustPlatform }:
+
+rustPlatform.buildRustPackage {
+ name = "mount-flatpak";
+
+ src = lib.fileset.toSource {
+ root = ../..;
+ fileset = lib.fileset.intersection src ./.;
+ };
+ sourceRoot = "source/tools/mount-flatpak";
+
+ cargoLock.lockFile = ./Cargo.lock;
+
+ env = {
+ MOUNT_FLATPAK_CONFIG_PATH = "${placeholder "out"}/share/spectrum/flatpak-config";
+ };
+
+ postInstall = ''
+ install -Dm 0755 config $MOUNT_FLATPAK_CONFIG_PATH
+ '';
+}) (_: {})
diff --git a/tools/mount-flatpak/src/keyfile.rs b/tools/mount-flatpak/src/keyfile.rs
new file mode 100644
index 0000000..fa746b3
--- /dev/null
+++ b/tools/mount-flatpak/src/keyfile.rs
@@ -0,0 +1,189 @@
+// Copyright 2021 System76 <info@system76.com>
+// SPDX-FileCopyrightText: 2025 Alyssa Ross <hi@alyssa.is>
+// SPDX-License-Identifier: MPL-2.0
+
+// Adapted from freedesktop-desktop-entry 0.7.19.
+
+use std::collections::BTreeMap;
+use std::fmt::{self, Display, Formatter};
+
+type Group = BTreeMap<String, String>;
+
+#[derive(Debug)]
+pub enum DecodeError {
+ KeyValueWithoutAGroup,
+ InvalidKey,
+ InvalidValue,
+}
+
+impl Display for DecodeError {
+ fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+ match self {
+ Self::KeyValueWithoutAGroup => write!(f, "key/value without a group"),
+ Self::InvalidKey => write!(f, "invalid key"),
+ Self::InvalidValue => write!(f, "invalid value"),
+ }
+ }
+}
+
+pub fn parse(input: &str) -> Result<BTreeMap<String, Group>, DecodeError> {
+ let mut groups = BTreeMap::default();
+ let mut active_group: Option<ActiveGroup> = None;
+ let mut active_keys: Option<ActiveKeys> = None;
+
+ for line in input.lines() {
+ process_line(line, &mut groups, &mut active_group, &mut active_keys)?;
+ }
+
+ if let Some(active_keys) = active_keys.take() {
+ match &mut active_group {
+ Some(active_group) => {
+ active_group
+ .group
+ .insert(active_keys.key_name, active_keys.value);
+ }
+ None => return Err(DecodeError::KeyValueWithoutAGroup),
+ }
+ }
+
+ if let Some(mut group) = active_group.take() {
+ groups
+ .entry(group.group_name)
+ .or_default()
+ .append(&mut group.group);
+ }
+
+ Ok(groups)
+}
+
+struct ActiveGroup {
+ group_name: String,
+ group: Group,
+}
+
+struct ActiveKeys {
+ key_name: String,
+ value: String,
+}
+
+#[inline(never)]
+fn process_line(
+ line: &str,
+ groups: &mut BTreeMap<String, Group>,
+ active_group: &mut Option<ActiveGroup>,
+ active_keys: &mut Option<ActiveKeys>,
+) -> Result<(), DecodeError> {
+ if line.trim().is_empty() || line.starts_with('#') {
+ return Ok(());
+ }
+
+ let line_bytes = line.as_bytes();
+
+ // if group
+ if line_bytes[0] == b'[' {
+ if let Some(end) = line_bytes[1..].iter().rposition(|&b| b == b']') {
+ let group_name = &line[1..end + 1];
+
+ if let Some(active_keys) = active_keys.take() {
+ match active_group {
+ Some(active_group) => {
+ active_group
+ .group
+ .insert(active_keys.key_name, active_keys.value);
+ }
+ None => return Err(DecodeError::KeyValueWithoutAGroup),
+ }
+ }
+
+ if let Some(mut group) = active_group.take() {
+ groups
+ .entry(group.group_name)
+ .or_default()
+ .append(&mut group.group);
+ }
+
+ active_group.replace(ActiveGroup {
+ group_name: group_name.to_string(),
+ group: Group::default(),
+ });
+ }
+ }
+ // else, if value
+ else if let Some(delimiter) = line_bytes.iter().position(|&b| b == b'=') {
+ let key = &line[..delimiter];
+ let value = format_value(&line[delimiter + 1..])?;
+
+ if key.is_empty() {
+ return Err(DecodeError::InvalidKey);
+ }
+
+ if let Some(active_keys) = active_keys.take() {
+ match active_group {
+ Some(active_group) => {
+ active_group
+ .group
+ .insert(active_keys.key_name, active_keys.value);
+ }
+ None => return Err(DecodeError::KeyValueWithoutAGroup),
+ }
+ }
+ active_keys.replace(ActiveKeys {
+ key_name: key.trim().to_string(),
+ value,
+ });
+ }
+ Ok(())
+}
+
+// https://specifications.freedesktop.org/desktop-entry-spec/latest/value-types.html
+#[inline]
+fn format_value(input: &str) -> Result<String, DecodeError> {
+ let input = if let Some(input) = input.strip_prefix(" ") {
+ input
+ } else {
+ input
+ };
+
+ let mut res = String::with_capacity(input.len());
+
+ let mut last: usize = 0;
+
+ for (i, v) in input.as_bytes().iter().enumerate() {
+ if *v != b'\\' {
+ continue;
+ }
+
+ // edge case for //
+ if last > i {
+ continue;
+ }
+
+ // when there is an \ at the end
+ if input.len() <= i + 1 {
+ return Err(DecodeError::InvalidValue);
+ }
+
+ if last < i {
+ res.push_str(&input[last..i]);
+ }
+
+ last = i + 2;
+
+ match input.as_bytes()[i + 1] {
+ b's' => res.push(' '),
+ b'n' => res.push('\n'),
+ b't' => res.push('\t'),
+ b'r' => res.push('\r'),
+ b'\\' => res.push('\\'),
+ _ => {
+ return Err(DecodeError::InvalidValue);
+ }
+ }
+ }
+
+ if last < input.len() {
+ res.push_str(&input[last..input.len()]);
+ }
+
+ Ok(res)
+}
diff --git a/tools/mount-flatpak/src/main.rs b/tools/mount-flatpak/src/main.rs
new file mode 100644
index 0000000..db246cd
--- /dev/null
+++ b/tools/mount-flatpak/src/main.rs
@@ -0,0 +1,296 @@
+// SPDX-FileCopyrightText: 2025 Alyssa Ross <hi@alyssa.is>
+// SPDX-License-Identifier: EUPL-1.2+
+
+//! Flatpak installations look like this:
+//!
+//! ```text
+//! flatpak/
+//! ├── app/
+//! │ └── org.gnome.TextEditor/
+//! │ ├── current -> x86_64/stable
+//! │ └── x86_64/
+//! │ └── stable/
+//! │ ├── 0029140121b39f5b7cf4d44fd46b0708eee67f395b5e1291628612a0358fb909/
+//! │ │ └── …
+//! │ └── active -> 0029140121b39f5b7cf4d44fd46b0708eee67f395b5e1291628612a0358fb909
+//! ├── db/
+//! ├── exports/
+//! │ └── …
+//! ├── repo
+//! │ ├── config
+//! │ ├── objects
+//! │ ├── tmp
+//! │ │ └── cache
+//! │ │ └── …
+//! │ └── …
+//! └── runtime
+//! ├── org.gnome.Platform
+//! │ └── x86_64
+//! │ └── 49
+//! │ ├── active -> bf6aa432cb310726f4ac0ec08cc88558619e1d4bd4b964e27e95187ecaad5400
+//! │ └── bf6aa432cb310726f4ac0ec08cc88558619e1d4bd4b964e27e95187ecaad5400
+//! │ └── …
+//! └── …
+//! ```
+//!
+//! The purpose of this program is to use bind mounts to construct a
+//! Flatpak installation containing only a single application and
+//! runtime, which can be passed through to a VM without exposing
+//! other installed applications.
+
+mod keyfile;
+mod metadata;
+
+use std::borrow::Cow;
+use std::env::{ArgsOs, args_os};
+use std::ffi::OsStr;
+use std::io;
+use std::os::unix::prelude::*;
+use std::path::{Path, PathBuf};
+use std::process::exit;
+
+use pathrs::Root;
+use pathrs::flags::{OpenFlags, ResolverFlags};
+use rustix::fs::{CWD, FileType, fstat};
+use rustix::mount::{MoveMountFlags, OpenTreeFlags, move_mount, open_tree};
+
+use metadata::extract_runtime;
+
+fn ex_usage() -> ! {
+ eprintln!("Usage: mount-flatpak userdata installation app");
+ exit(1);
+}
+
+fn run(mut args: ArgsOs) -> Result<(), String> {
+ let Some(user_data_path) = args.next().map(PathBuf::from) else {
+ ex_usage();
+ };
+ let Some(installation_path) = args.next().map(PathBuf::from) else {
+ ex_usage();
+ };
+ let Some(app) = args.next() else {
+ ex_usage();
+ };
+ if args.next().is_some() {
+ ex_usage();
+ }
+
+ let mut user_data =
+ Root::open(&user_data_path).map_err(|e| format!("opening user data partition: {e}"))?;
+ user_data.set_resolver_flags(ResolverFlags::NO_SYMLINKS);
+
+ let mut source_installation_dir = user_data
+ .open_subpath(&installation_path, OpenFlags::O_PATH)
+ .map(Root::from_fd)
+ .map_err(|e| format!("opening source flatpak installation: {e}"))?;
+ source_installation_dir.set_resolver_flags(ResolverFlags::NO_SYMLINKS);
+
+ std::fs::create_dir("flatpak")
+ .map_err(|e| format!("creating target flatpak installation: {e}"))?;
+
+ let target_installation_dir = open_tree(
+ CWD,
+ "flatpak",
+ OpenTreeFlags::OPEN_TREE_CLONE
+ | OpenTreeFlags::OPEN_TREE_CLOEXEC
+ | OpenTreeFlags::AT_RECURSIVE
+ | OpenTreeFlags::AT_SYMLINK_NOFOLLOW,
+ )
+ .map_err(|e| format!("opening target flatpak installation: {e}"))?;
+ let mut target_installation_dir = Root::from_fd(target_installation_dir);
+ target_installation_dir.set_resolver_flags(ResolverFlags::NO_SYMLINKS);
+
+ let mut full_app_path = installation_path.join("app");
+ full_app_path.push(&app);
+ full_app_path.push("current");
+ let arch_and_branch = source_installation_dir
+ .readlink(&full_app_path)
+ .map_err(|e| format!("reading current app arch and branch: {e}"))?;
+ let mut components = arch_and_branch.components();
+ let arch = components.next().unwrap().as_os_str();
+ let branch = components.as_path().as_os_str();
+ if branch.is_empty() {
+ return Err("can't infer branch from \"current\" link".to_string());
+ }
+
+ full_app_path.pop();
+ full_app_path.push(&arch_and_branch);
+ full_app_path.push("active");
+ let commit = source_installation_dir
+ .readlink(&full_app_path)
+ .map_err(|e| format!("reading active app commit: {e}"))?
+ .into_os_string();
+
+ full_app_path.pop();
+ full_app_path.push(&commit);
+ let source_app_dir = source_installation_dir
+ .resolve(&full_app_path)
+ .map_err(|e| format!("opening source app directory: {e}"))?;
+
+ let metadata = source_installation_dir
+ .resolve(full_app_path.join("metadata"))
+ .map_err(|e| format!("resolving app metadata: {e}"))?;
+
+ let metadata_stat =
+ fstat(&metadata).map_err(|e| format!("checking app metadata is a regular file: {e}"))?;
+ let metadata_type = FileType::from_raw_mode(metadata_stat.st_mode);
+ if !metadata_type.is_file() {
+ let e = format!("type of app metadata is {metadata_type:?}, not RegularFile");
+ return Err(e);
+ }
+ let metadata = metadata
+ .reopen(OpenFlags::O_RDONLY)
+ .map_err(|e| format!("opening app metadata: {e}"))?;
+
+ let runtime =
+ extract_runtime(metadata).map_err(|e| format!("reading runtime from metadata: {e}"))?;
+
+ let mut full_runtime_path = installation_path.join("runtime");
+ full_runtime_path.push(runtime);
+ full_runtime_path.push("active");
+ let runtime_commit = source_installation_dir
+ .readlink(&full_runtime_path)
+ .map_err(|e| format!("reading active runtime commit: {e}"))?
+ .into_os_string();
+
+ full_runtime_path.pop();
+ full_runtime_path.push(&runtime_commit);
+ let source_runtime_dir = source_installation_dir
+ .resolve(&full_runtime_path)
+ .map_err(|e| format!("opening source runtime directory: {e}"))?;
+
+ let target_app_dir = target_installation_dir
+ .mkdir_all(&full_app_path, &PermissionsExt::from_mode(0o700))
+ .map_err(|e| format!("creating target app directory: {e}"))?;
+ let target_runtime_dir = target_installation_dir
+ .mkdir_all(&full_runtime_path, &PermissionsExt::from_mode(0o700))
+ .map_err(|e| format!("creating target runtime directory: {e}"))?;
+
+ let source_app_tree = open_tree(
+ &source_app_dir,
+ "",
+ OpenTreeFlags::AT_EMPTY_PATH
+ | OpenTreeFlags::OPEN_TREE_CLONE
+ | OpenTreeFlags::OPEN_TREE_CLOEXEC
+ | OpenTreeFlags::AT_RECURSIVE,
+ )
+ .map_err(|e| format!("cloning source app tree: {e}"))?;
+ let source_runtime_tree = open_tree(
+ &source_runtime_dir,
+ "",
+ OpenTreeFlags::AT_EMPTY_PATH
+ | OpenTreeFlags::OPEN_TREE_CLONE
+ | OpenTreeFlags::OPEN_TREE_CLOEXEC
+ | OpenTreeFlags::AT_RECURSIVE,
+ )
+ .map_err(|e| format!("cloning source runtime tree: {e}"))?;
+
+ move_mount(
+ source_app_tree,
+ "",
+ target_app_dir,
+ "",
+ MoveMountFlags::MOVE_MOUNT_F_EMPTY_PATH | MoveMountFlags::MOVE_MOUNT_T_EMPTY_PATH,
+ )
+ .map_err(|e| format!("mounting app directory: {e}"))?;
+ move_mount(
+ source_runtime_tree,
+ "",
+ target_runtime_dir,
+ "",
+ MoveMountFlags::MOVE_MOUNT_F_EMPTY_PATH | MoveMountFlags::MOVE_MOUNT_T_EMPTY_PATH,
+ )
+ .map_err(|e| format!("mounting runtime directory: {e}"))?;
+
+ target_installation_dir
+ .mkdir_all("repo/objects", &PermissionsExt::from_mode(0o700))
+ .map_err(|e| format!("creating repo/objects: {e}"))?;
+ target_installation_dir
+ .mkdir_all("repo/tmp/cache", &PermissionsExt::from_mode(0o700))
+ .map_err(|e| format!("creating repo/tmp/cache: {e}"))?;
+ let config_target = target_installation_dir
+ .create_file(
+ "repo/config",
+ OpenFlags::O_WRONLY | OpenFlags::O_CLOEXEC,
+ &PermissionsExt::from_mode(0o700),
+ )
+ .map_err(|e| format!("creating repo/config: {e}"))?;
+ let config_source_path = env!("MOUNT_FLATPAK_CONFIG_PATH");
+ let config_source = open_tree(
+ CWD,
+ config_source_path,
+ OpenTreeFlags::OPEN_TREE_CLONE | OpenTreeFlags::OPEN_TREE_CLOEXEC,
+ )
+ .map_err(|e| format!("opening {config_source_path}: {e}"))?;
+ move_mount(
+ config_source,
+ "",
+ config_target,
+ "",
+ MoveMountFlags::MOVE_MOUNT_F_EMPTY_PATH | MoveMountFlags::MOVE_MOUNT_T_EMPTY_PATH,
+ )
+ .map_err(|e| format!("mounting config: {e}"))?;
+
+ let mut attr = libc::mount_attr {
+ attr_clr: libc::MOUNT_ATTR_NOSYMFOLLOW,
+ attr_set: libc::MOUNT_ATTR_RDONLY | libc::MOUNT_ATTR_NODEV,
+ propagation: libc::MS_SLAVE,
+ userns_fd: 0,
+ };
+ let empty = b"\0";
+ // SAFETY: we pass a valid FD, and a valid mutable pointer with the correct size.
+ unsafe {
+ let r = libc::syscall(
+ libc::SYS_mount_setattr,
+ target_installation_dir.as_fd().as_raw_fd() as libc::c_long,
+ empty.as_ptr() as *const libc::c_char,
+ (libc::AT_EMPTY_PATH | libc::AT_RECURSIVE) as libc::c_long,
+ &mut attr as *mut libc::mount_attr,
+ size_of::<libc::mount_attr>() as libc::c_long,
+ );
+ if r == -1 {
+ return Err(format!(
+ "setting target mount attributes: {}",
+ io::Error::last_os_error()
+ ));
+ }
+ }
+ move_mount(
+ target_installation_dir,
+ "",
+ CWD,
+ "flatpak",
+ MoveMountFlags::MOVE_MOUNT_F_EMPTY_PATH,
+ )
+ .map_err(|e| format!("mounting target installation dir: {e}"))?;
+
+ std::fs::create_dir("params").map_err(|e| format!("creating params directory: {e}"))?;
+ std::fs::write("params/id", app.as_bytes()).map_err(|e| format!("writing params/id: {e}"))?;
+ std::fs::write("params/commit", commit.as_bytes())
+ .map_err(|e| format!("writing params/commit: {e}"))?;
+ std::fs::write("params/arch", arch.as_bytes())
+ .map_err(|e| format!("writing params/arch: {e}"))?;
+ std::fs::write("params/branch", branch.as_bytes())
+ .map_err(|e| format!("writing params/branch: {e}"))?;
+ std::fs::write("params/runtime-commit", runtime_commit.as_bytes())
+ .map_err(|e| format!("writing params/runtime-commit: {e}"))?;
+
+ Ok(())
+}
+
+fn main() {
+ let mut args = args_os();
+
+ let prog_name = args
+ .next()
+ .as_ref()
+ .map(Path::new)
+ .and_then(Path::file_name)
+ .map_or(Cow::Borrowed("mount-flatpak"), OsStr::to_string_lossy)
+ .into_owned();
+
+ if let Err(e) = run(args) {
+ eprintln!("{prog_name}: {e}");
+ exit(1);
+ }
+}
diff --git a/tools/mount-flatpak/src/metadata.rs b/tools/mount-flatpak/src/metadata.rs
new file mode 100644
index 0000000..dfc05b1
--- /dev/null
+++ b/tools/mount-flatpak/src/metadata.rs
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: EUPL-1.2+
+// SPDX-FileCopyrightText: 2025 Alyssa Ross <hi@alyssa.is>
+
+use std::fs::File;
+use std::io::read_to_string;
+
+use crate::keyfile::parse;
+
+pub fn extract_runtime(mut metadata: File) -> Result<String, String> {
+ let metadata = read_to_string(&mut metadata).map_err(|e| e.to_string())?;
+ let group = parse(&metadata).map_err(|e| e.to_string())?;
+ let application = group
+ .get("Application")
+ .ok_or_else(|| "Application group missing".to_string())?;
+ Ok(application
+ .get("runtime")
+ .ok_or_else(|| "runtime property missing".to_string())?
+ .clone())
+}
--
2.51.0
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH v4 4/5] img/app: run Flatpak applications
2025-12-01 4:45 [PATCH 1/5] img/app: install fuse3 globally Alyssa Ross
2025-12-01 4:45 ` [PATCH 2/5] host/rootfs: create a per-VM mount namespace Alyssa Ross
2025-12-01 4:45 ` [PATCH v4 3/5] tools/mount-flatpak: init Alyssa Ross
@ 2025-12-01 4:45 ` Alyssa Ross
2025-12-01 4:45 ` [PATCH v4 5/5] host/rootfs: add run-flatpak script Alyssa Ross
3 siblings, 0 replies; 11+ messages in thread
From: Alyssa Ross @ 2025-12-01 4:45 UTC (permalink / raw)
To: devel; +Cc: Demi Marie Obenour
Signed-off-by: Alyssa Ross <hi@alyssa.is>
---
v4: no change
v3: https://spectrum-os.org/lists/archives/spectrum-devel/20251127202311.42422-5-hi@alyssa.is/
img/app/default.nix | 1 +
img/app/file-list.mk | 1 +
| 5 +++++
img/app/image/etc/s6-rc/app/run | 14 +++++++++++++-
4 files changed, 20 insertions(+), 1 deletion(-)
create mode 100644 img/app/image/etc/flatpak/installations.d/extra.conf
diff --git a/img/app/default.nix b/img/app/default.nix
index 1eb3c9b..71e6fa0 100644
--- a/img/app/default.nix
+++ b/img/app/default.nix
@@ -49,6 +49,7 @@ let
name = "vm-fhs-env";
targetPkgs = pkgs: appimageTools.defaultFhsEnvArgs.targetPkgs pkgs ++ [
pkgs.fuse
+ pkgs.flatpak
(pkgs.busybox.override {
enableMinimal = true;
diff --git a/img/app/file-list.mk b/img/app/file-list.mk
index 6934975..4fbdec2 100644
--- a/img/app/file-list.mk
+++ b/img/app/file-list.mk
@@ -3,6 +3,7 @@
FILES = \
image/etc/dbus-1/session.conf \
+ image/etc/flatpak/installations.d/extra.conf \
image/etc/fstab \
image/etc/mdev.conf \
image/etc/mdev/iface \
--git a/img/app/image/etc/flatpak/installations.d/extra.conf b/img/app/image/etc/flatpak/installations.d/extra.conf
new file mode 100644
index 0000000..448902b
--- /dev/null
+++ b/img/app/image/etc/flatpak/installations.d/extra.conf
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: CC0-1.0
+# SPDX-FileCopyrightText: 2025 Alyssa Ross <hi@alyssa.is>
+
+[Installation "virtiofs"]
+Path=/run/virtiofs/virtiofs0/config/flatpak
diff --git a/img/app/image/etc/s6-rc/app/run b/img/app/image/etc/s6-rc/app/run
index 601926b..4b3b8d6 100755
--- a/img/app/image/etc/s6-rc/app/run
+++ b/img/app/image/etc/s6-rc/app/run
@@ -1,6 +1,6 @@
#!/bin/execlineb -P
# SPDX-License-Identifier: EUPL-1.2+
-# SPDX-FileCopyrightText: 2021, 2024 Alyssa Ross <hi@alyssa.is>
+# SPDX-FileCopyrightText: 2021, 2024-2025 Alyssa Ross <hi@alyssa.is>
export TMPDIR /run
@@ -25,6 +25,18 @@ foreground {
export LD_LIBRARY_PATH /lib64
/run/virtiofs/virtiofs0/config/run
}
+ flatpak {
+ s6-envdir -fnL /run/virtiofs/virtiofs0/config/params
+ multisubstitute {
+ importas -iu id id
+ importas -iu arch arch
+ importas -iu branch branch
+ importas -iu commit commit
+ importas -iu runtime_commit runtime-commit
+ }
+ flatpak run --installation=virtiofs --arch=${arch} --branch=${branch}
+ --commit=${commit} --runtime-commit=${runtime_commit} $id
+ }
nix {
if {
mount -t overlay
--
2.51.0
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH v4 5/5] host/rootfs: add run-flatpak script
2025-12-01 4:45 [PATCH 1/5] img/app: install fuse3 globally Alyssa Ross
` (2 preceding siblings ...)
2025-12-01 4:45 ` [PATCH v4 4/5] img/app: run Flatpak applications Alyssa Ross
@ 2025-12-01 4:45 ` Alyssa Ross
2025-12-01 5:20 ` Demi Marie Obenour
3 siblings, 1 reply; 11+ messages in thread
From: Alyssa Ross @ 2025-12-01 4:45 UTC (permalink / raw)
To: devel; +Cc: Demi Marie Obenour
This is the entrypoint for running Flatpak applications.
It would be good to only add mounts for the VM in virtiofsd's mount
namespace, so we don't need to do lots of manual unmounts, but that's
a wider change affecting more than just Flatpak.
I've tested this by copying my host's Flatpak repository into a disk
image, and attaching that as a drive to the VM.
Signed-off-by: Alyssa Ross <hi@alyssa.is>
---
v4: use the new VM mount namespace
v3: https://spectrum-os.org/lists/archives/spectrum-devel/20251127202311.42422-7-hi@alyssa.is/
host/rootfs/default.nix | 12 +++----
host/rootfs/file-list.mk | 1 +
host/rootfs/image/usr/bin/run-flatpak | 47 +++++++++++++++++++++++++++
3 files changed, 54 insertions(+), 6 deletions(-)
create mode 100755 host/rootfs/image/usr/bin/run-flatpak
diff --git a/host/rootfs/default.nix b/host/rootfs/default.nix
index 57dd7a9..ca2084f 100644
--- a/host/rootfs/default.nix
+++ b/host/rootfs/default.nix
@@ -12,9 +12,9 @@ pkgsMusl.callPackage (
, lib, stdenvNoCC, nixos, runCommand, writeClosure, erofs-utils, s6-rc
, btrfs-progs, busybox, cloud-hypervisor, cosmic-files, crosvm
, cryptsetup, dejavu_fonts, dbus, execline, foot, fuse3, iproute2
-, inotify-tools, jq, kmod, mdevd, mesa, s6, s6-linux-init, socat
-, systemd, util-linuxMinimal, virtiofsd, westonLite
-, xdg-desktop-portal, xdg-desktop-portal-gtk
+, inotify-tools, jq, kmod, mdevd, mesa, mount-flatpak, s6
+, s6-linux-init, socat, systemd, util-linuxMinimal, virtiofsd
+, westonLite, xdg-desktop-portal, xdg-desktop-portal-gtk
, xdg-desktop-portal-spectrum-host
}:
@@ -26,9 +26,9 @@ let
packages = [
btrfs-progs cloud-hypervisor cosmic-files crosvm cryptsetup dbus
- execline fuse3 inotify-tools iproute2 jq kmod mdevd s6 s6-linux-init
- s6-rc socat spectrum-host-tools spectrum-router util-linuxMinimal virtiofsd
- xdg-desktop-portal-spectrum-host
+ execline fuse3 inotify-tools iproute2 jq kmod mdevd mount-flatpak s6
+ s6-linux-init s6-rc socat spectrum-host-tools spectrum-router
+ util-linuxMinimal virtiofsd xdg-desktop-portal-spectrum-host
(foot.override { allowPgo = false; })
diff --git a/host/rootfs/file-list.mk b/host/rootfs/file-list.mk
index bfe3940..df22bce 100644
--- a/host/rootfs/file-list.mk
+++ b/host/rootfs/file-list.mk
@@ -55,6 +55,7 @@ FILES = \
image/usr/bin/assign-devices \
image/usr/bin/create-vm-dependencies \
image/usr/bin/run-appimage \
+ image/usr/bin/run-flatpak \
image/usr/bin/run-vmm \
image/usr/bin/spectrum-update \
image/usr/bin/vm-console \
diff --git a/host/rootfs/image/usr/bin/run-flatpak b/host/rootfs/image/usr/bin/run-flatpak
new file mode 100755
index 0000000..d7914a7
--- /dev/null
+++ b/host/rootfs/image/usr/bin/run-flatpak
@@ -0,0 +1,47 @@
+#!/bin/execlineb -W
+# SPDX-License-Identifier: EUPL-1.2+
+# SPDX-FileCopyrightText: 2024-2025 Alyssa Ross <hi@alyssa.is>
+
+backtick -E dir { mktemp -d /run/vm/by-id/XXXXXX }
+backtick -E id { basename -- $dir }
+
+if {
+ elgetpositionals
+
+ if { mkdir -p /run/configs/${id}/fs }
+
+ if {
+ ln -s /usr/lib/spectrum/img/appvm/blk /usr/lib/spectrum/img/appvm/vmlinux
+ /run/configs/${id}
+ }
+
+ if { ln -s /run/configs/${id} ${dir}/config }
+
+ if { create-vm-dependencies $id }
+
+ if {
+ nsenter --mount=${dir}/mount
+ cd ${dir}/fs/config
+ if { redirfd -w 1 type echo flatpak }
+ mount-flatpak $@
+ }
+
+ piperw 4 3
+ background {
+ fdclose 3
+ fdmove 0 4
+
+ # Wait for the VMM to be up, then start the VM.
+ if { redirfd -w 1 /dev/null head -1 }
+ vm-start $id
+ }
+ fdclose 4
+
+ foreground { run-vmm $id }
+}
+
+if { s6-instance-delete -- /run/service/vm-services $id }
+
+if { umount ${dir}/mount } # mount namespace
+if { umount ${dir}/mount } # private bind mount
+rm -r $dir /run/configs/${id}
--
2.51.0
^ permalink raw reply related [flat|nested] 11+ messages in thread
* Re: [PATCH 2/5] host/rootfs: create a per-VM mount namespace
2025-12-01 4:45 ` [PATCH 2/5] host/rootfs: create a per-VM mount namespace Alyssa Ross
@ 2025-12-01 4:52 ` Demi Marie Obenour
2025-12-01 14:33 ` Alyssa Ross
0 siblings, 1 reply; 11+ messages in thread
From: Demi Marie Obenour @ 2025-12-01 4:52 UTC (permalink / raw)
To: Alyssa Ross, devel
[-- Attachment #1.1.1: Type: text/plain, Size: 5789 bytes --]
On 11/30/25 23:45, Alyssa Ross wrote:
> 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.
Does the updater also need to be adjusted?
> Signed-off-by: Alyssa Ross <hi@alyssa.is>
> ---
> .../template/data/service/dbus/run | 2 ++
> .../template/data/service/vhost-user-fs/run | 4 +--
> .../image/usr/bin/create-vm-dependencies | 23 ++++++++++++++---
> host/rootfs/image/usr/bin/run-appimage | 25 +++++++++----------
> 4 files changed, 34 insertions(+), 20 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..3848b0c 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
> @@ -12,8 +12,6 @@ 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.
Comment should be moved to the code that does the bind mount. Also,
this comment is somewhat stale: the main reason to prevent writing
into the toplevel fs/ folder is that host tools (like the updater)
assume symlinks can't be created in it.
> -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 ${VM}/fs
> diff --git a/host/rootfs/image/usr/bin/create-vm-dependencies b/host/rootfs/image/usr/bin/create-vm-dependencies
> index f3a1b69..21681cd 100755
> --- a/host/rootfs/image/usr/bin/create-vm-dependencies
> +++ b/host/rootfs/image/usr/bin/create-vm-dependencies
> @@ -1,11 +1,26 @@
> #!/bin/execlineb -S1
> # SPDX-License-Identifier: EUPL-1.2+
> -# SPDX-FileCopyrightText: 2024 Alyssa Ross <hi@alyssa.is>
> +# SPDX-FileCopyrightText: 2024-2025 Alyssa Ross <hi@alyssa.is>
>
> -if { mount -m --rbind -o nofail /run/vm/by-id/${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 --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
I would also create /run/vm/by-id/${1}/config/fs...
> + }
> +
> + if { mount --make-shared --rbind /run/vm/by-id/${1} /run/vm/by-id/${1} }
> +
> + if { mount --rbind -o ro /run/vm/by-id/${1}/fs /run/vm/by-id/${1}/fs }
VMs should not be able to write to their own config, so this and the
next like should be swapped.
> + if { mount --rbind -o nofail /run/vm/by-id/${1}/config/fs /run/vm/by-id/${1}/fs/config }
...and remove this `-o nofail`.
> + mount --rbind /run/vm/by-id/${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}
--
Sincerely,
Demi Marie Obenour (she/her/hers)
[-- Attachment #1.1.2: OpenPGP public key --]
[-- Type: application/pgp-keys, Size: 7253 bytes --]
[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v4 3/5] tools/mount-flatpak: init
2025-12-01 4:45 ` [PATCH v4 3/5] tools/mount-flatpak: init Alyssa Ross
@ 2025-12-01 5:14 ` Demi Marie Obenour
2025-12-01 11:49 ` Alyssa Ross
0 siblings, 1 reply; 11+ messages in thread
From: Demi Marie Obenour @ 2025-12-01 5:14 UTC (permalink / raw)
To: Alyssa Ross, devel
[-- Attachment #1.1.1: Type: text/plain, Size: 50552 bytes --]
On 11/30/25 23:45, Alyssa Ross wrote:
> I tried to build this with Meson, but pathrs depends on thiserror,
> which tries to read OUT_DIR, and support for setting that isn't
> currently in a Meson release, and requires nightly Rust, so build with
> Cargo for now and we can revisit that later.
>
> Link: https://github.com/mesonbuild/meson/pull/15148
> Link: https://github.com/rust-lang/rust/issues/118372
> Signed-off-by: Alyssa Ross <hi@alyssa.is>
> ---
> v4: • Open a root for the Flatpak installation to limit scope
> • Update usage
> • Call open_tree with AT_SYMLINK_NOFOLLOW
> • Add comment explaining purpose and directory structure
> • Set MS_SLAVE on the final mount
> • Cast non-pointer syscall arguments to long
> v3: https://spectrum-os.org/lists/archives/spectrum-devel/20251127202311.42422-2-hi@alyssa.is/
>
> LICENSES/MPL-2.0.txt | 373 +++++++++++++++++++++++++
> pkgs/default.nix | 1 +
> tools/mount-flatpak/Cargo.lock | 238 ++++++++++++++++
> tools/mount-flatpak/Cargo.lock.license | 2 +
> tools/mount-flatpak/Cargo.toml | 11 +
> tools/mount-flatpak/config | 7 +
> tools/mount-flatpak/default.nix | 25 ++
> tools/mount-flatpak/src/keyfile.rs | 189 +++++++++++++
> tools/mount-flatpak/src/main.rs | 296 ++++++++++++++++++++
> tools/mount-flatpak/src/metadata.rs | 19 ++
> 10 files changed, 1161 insertions(+)
> create mode 100644 LICENSES/MPL-2.0.txt
> create mode 100644 tools/mount-flatpak/Cargo.lock
> create mode 100644 tools/mount-flatpak/Cargo.lock.license
> create mode 100644 tools/mount-flatpak/Cargo.toml
> create mode 100644 tools/mount-flatpak/config
> create mode 100644 tools/mount-flatpak/default.nix
> create mode 100644 tools/mount-flatpak/src/keyfile.rs
> create mode 100644 tools/mount-flatpak/src/main.rs
> create mode 100644 tools/mount-flatpak/src/metadata.rs
>
> diff --git a/LICENSES/MPL-2.0.txt b/LICENSES/MPL-2.0.txt
> new file mode 100644
> index 0000000..d0a1fa1
> --- /dev/null
> +++ b/LICENSES/MPL-2.0.txt
> @@ -0,0 +1,373 @@
> +Mozilla Public License Version 2.0
> +==================================
> +
> +1. Definitions
> +--------------
> +
> +1.1. "Contributor"
> + means each individual or legal entity that creates, contributes to
> + the creation of, or owns Covered Software.
> +
> +1.2. "Contributor Version"
> + means the combination of the Contributions of others (if any) used
> + by a Contributor and that particular Contributor's Contribution.
> +
> +1.3. "Contribution"
> + means Covered Software of a particular Contributor.
> +
> +1.4. "Covered Software"
> + means Source Code Form to which the initial Contributor has attached
> + the notice in Exhibit A, the Executable Form of such Source Code
> + Form, and Modifications of such Source Code Form, in each case
> + including portions thereof.
> +
> +1.5. "Incompatible With Secondary Licenses"
> + means
> +
> + (a) that the initial Contributor has attached the notice described
> + in Exhibit B to the Covered Software; or
> +
> + (b) that the Covered Software was made available under the terms of
> + version 1.1 or earlier of the License, but not also under the
> + terms of a Secondary License.
> +
> +1.6. "Executable Form"
> + means any form of the work other than Source Code Form.
> +
> +1.7. "Larger Work"
> + means a work that combines Covered Software with other material, in
> + a separate file or files, that is not Covered Software.
> +
> +1.8. "License"
> + means this document.
> +
> +1.9. "Licensable"
> + means having the right to grant, to the maximum extent possible,
> + whether at the time of the initial grant or subsequently, any and
> + all of the rights conveyed by this License.
> +
> +1.10. "Modifications"
> + means any of the following:
> +
> + (a) any file in Source Code Form that results from an addition to,
> + deletion from, or modification of the contents of Covered
> + Software; or
> +
> + (b) any new file in Source Code Form that contains any Covered
> + Software.
> +
> +1.11. "Patent Claims" of a Contributor
> + means any patent claim(s), including without limitation, method,
> + process, and apparatus claims, in any patent Licensable by such
> + Contributor that would be infringed, but for the grant of the
> + License, by the making, using, selling, offering for sale, having
> + made, import, or transfer of either its Contributions or its
> + Contributor Version.
> +
> +1.12. "Secondary License"
> + means either the GNU General Public License, Version 2.0, the GNU
> + Lesser General Public License, Version 2.1, the GNU Affero General
> + Public License, Version 3.0, or any later versions of those
> + licenses.
> +
> +1.13. "Source Code Form"
> + means the form of the work preferred for making modifications.
> +
> +1.14. "You" (or "Your")
> + means an individual or a legal entity exercising rights under this
> + License. For legal entities, "You" includes any entity that
> + controls, is controlled by, or is under common control with You. For
> + purposes of this definition, "control" means (a) the power, direct
> + or indirect, to cause the direction or management of such entity,
> + whether by contract or otherwise, or (b) ownership of more than
> + fifty percent (50%) of the outstanding shares or beneficial
> + ownership of such entity.
> +
> +2. License Grants and Conditions
> +--------------------------------
> +
> +2.1. Grants
> +
> +Each Contributor hereby grants You a world-wide, royalty-free,
> +non-exclusive license:
> +
> +(a) under intellectual property rights (other than patent or trademark)
> + Licensable by such Contributor to use, reproduce, make available,
> + modify, display, perform, distribute, and otherwise exploit its
> + Contributions, either on an unmodified basis, with Modifications, or
> + as part of a Larger Work; and
> +
> +(b) under Patent Claims of such Contributor to make, use, sell, offer
> + for sale, have made, import, and otherwise transfer either its
> + Contributions or its Contributor Version.
> +
> +2.2. Effective Date
> +
> +The licenses granted in Section 2.1 with respect to any Contribution
> +become effective for each Contribution on the date the Contributor first
> +distributes such Contribution.
> +
> +2.3. Limitations on Grant Scope
> +
> +The licenses granted in this Section 2 are the only rights granted under
> +this License. No additional rights or licenses will be implied from the
> +distribution or licensing of Covered Software under this License.
> +Notwithstanding Section 2.1(b) above, no patent license is granted by a
> +Contributor:
> +
> +(a) for any code that a Contributor has removed from Covered Software;
> + or
> +
> +(b) for infringements caused by: (i) Your and any other third party's
> + modifications of Covered Software, or (ii) the combination of its
> + Contributions with other software (except as part of its Contributor
> + Version); or
> +
> +(c) under Patent Claims infringed by Covered Software in the absence of
> + its Contributions.
> +
> +This License does not grant any rights in the trademarks, service marks,
> +or logos of any Contributor (except as may be necessary to comply with
> +the notice requirements in Section 3.4).
> +
> +2.4. Subsequent Licenses
> +
> +No Contributor makes additional grants as a result of Your choice to
> +distribute the Covered Software under a subsequent version of this
> +License (see Section 10.2) or under the terms of a Secondary License (if
> +permitted under the terms of Section 3.3).
> +
> +2.5. Representation
> +
> +Each Contributor represents that the Contributor believes its
> +Contributions are its original creation(s) or it has sufficient rights
> +to grant the rights to its Contributions conveyed by this License.
> +
> +2.6. Fair Use
> +
> +This License is not intended to limit any rights You have under
> +applicable copyright doctrines of fair use, fair dealing, or other
> +equivalents.
> +
> +2.7. Conditions
> +
> +Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted
> +in Section 2.1.
> +
> +3. Responsibilities
> +-------------------
> +
> +3.1. Distribution of Source Form
> +
> +All distribution of Covered Software in Source Code Form, including any
> +Modifications that You create or to which You contribute, must be under
> +the terms of this License. You must inform recipients that the Source
> +Code Form of the Covered Software is governed by the terms of this
> +License, and how they can obtain a copy of this License. You may not
> +attempt to alter or restrict the recipients' rights in the Source Code
> +Form.
> +
> +3.2. Distribution of Executable Form
> +
> +If You distribute Covered Software in Executable Form then:
> +
> +(a) such Covered Software must also be made available in Source Code
> + Form, as described in Section 3.1, and You must inform recipients of
> + the Executable Form how they can obtain a copy of such Source Code
> + Form by reasonable means in a timely manner, at a charge no more
> + than the cost of distribution to the recipient; and
> +
> +(b) You may distribute such Executable Form under the terms of this
> + License, or sublicense it under different terms, provided that the
> + license for the Executable Form does not attempt to limit or alter
> + the recipients' rights in the Source Code Form under this License.
> +
> +3.3. Distribution of a Larger Work
> +
> +You may create and distribute a Larger Work under terms of Your choice,
> +provided that You also comply with the requirements of this License for
> +the Covered Software. If the Larger Work is a combination of Covered
> +Software with a work governed by one or more Secondary Licenses, and the
> +Covered Software is not Incompatible With Secondary Licenses, this
> +License permits You to additionally distribute such Covered Software
> +under the terms of such Secondary License(s), so that the recipient of
> +the Larger Work may, at their option, further distribute the Covered
> +Software under the terms of either this License or such Secondary
> +License(s).
> +
> +3.4. Notices
> +
> +You may not remove or alter the substance of any license notices
> +(including copyright notices, patent notices, disclaimers of warranty,
> +or limitations of liability) contained within the Source Code Form of
> +the Covered Software, except that You may alter any license notices to
> +the extent required to remedy known factual inaccuracies.
> +
> +3.5. Application of Additional Terms
> +
> +You may choose to offer, and to charge a fee for, warranty, support,
> +indemnity or liability obligations to one or more recipients of Covered
> +Software. However, You may do so only on Your own behalf, and not on
> +behalf of any Contributor. You must make it absolutely clear that any
> +such warranty, support, indemnity, or liability obligation is offered by
> +You alone, and You hereby agree to indemnify every Contributor for any
> +liability incurred by such Contributor as a result of warranty, support,
> +indemnity or liability terms You offer. You may include additional
> +disclaimers of warranty and limitations of liability specific to any
> +jurisdiction.
> +
> +4. Inability to Comply Due to Statute or Regulation
> +---------------------------------------------------
> +
> +If it is impossible for You to comply with any of the terms of this
> +License with respect to some or all of the Covered Software due to
> +statute, judicial order, or regulation then You must: (a) comply with
> +the terms of this License to the maximum extent possible; and (b)
> +describe the limitations and the code they affect. Such description must
> +be placed in a text file included with all distributions of the Covered
> +Software under this License. Except to the extent prohibited by statute
> +or regulation, such description must be sufficiently detailed for a
> +recipient of ordinary skill to be able to understand it.
> +
> +5. Termination
> +--------------
> +
> +5.1. The rights granted under this License will terminate automatically
> +if You fail to comply with any of its terms. However, if You become
> +compliant, then the rights granted under this License from a particular
> +Contributor are reinstated (a) provisionally, unless and until such
> +Contributor explicitly and finally terminates Your grants, and (b) on an
> +ongoing basis, if such Contributor fails to notify You of the
> +non-compliance by some reasonable means prior to 60 days after You have
> +come back into compliance. Moreover, Your grants from a particular
> +Contributor are reinstated on an ongoing basis if such Contributor
> +notifies You of the non-compliance by some reasonable means, this is the
> +first time You have received notice of non-compliance with this License
> +from such Contributor, and You become compliant prior to 30 days after
> +Your receipt of the notice.
> +
> +5.2. If You initiate litigation against any entity by asserting a patent
> +infringement claim (excluding declaratory judgment actions,
> +counter-claims, and cross-claims) alleging that a Contributor Version
> +directly or indirectly infringes any patent, then the rights granted to
> +You by any and all Contributors for the Covered Software under Section
> +2.1 of this License shall terminate.
> +
> +5.3. In the event of termination under Sections 5.1 or 5.2 above, all
> +end user license agreements (excluding distributors and resellers) which
> +have been validly granted by You or Your distributors under this License
> +prior to termination shall survive termination.
> +
> +************************************************************************
> +* *
> +* 6. Disclaimer of Warranty *
> +* ------------------------- *
> +* *
> +* Covered Software is provided under this License on an "as is" *
> +* basis, without warranty of any kind, either expressed, implied, or *
> +* statutory, including, without limitation, warranties that the *
> +* Covered Software is free of defects, merchantable, fit for a *
> +* particular purpose or non-infringing. The entire risk as to the *
> +* quality and performance of the Covered Software is with You. *
> +* Should any Covered Software prove defective in any respect, You *
> +* (not any Contributor) assume the cost of any necessary servicing, *
> +* repair, or correction. This disclaimer of warranty constitutes an *
> +* essential part of this License. No use of any Covered Software is *
> +* authorized under this License except under this disclaimer. *
> +* *
> +************************************************************************
> +
> +************************************************************************
> +* *
> +* 7. Limitation of Liability *
> +* -------------------------- *
> +* *
> +* Under no circumstances and under no legal theory, whether tort *
> +* (including negligence), contract, or otherwise, shall any *
> +* Contributor, or anyone who distributes Covered Software as *
> +* permitted above, be liable to You for any direct, indirect, *
> +* special, incidental, or consequential damages of any character *
> +* including, without limitation, damages for lost profits, loss of *
> +* goodwill, work stoppage, computer failure or malfunction, or any *
> +* and all other commercial damages or losses, even if such party *
> +* shall have been informed of the possibility of such damages. This *
> +* limitation of liability shall not apply to liability for death or *
> +* personal injury resulting from such party's negligence to the *
> +* extent applicable law prohibits such limitation. Some *
> +* jurisdictions do not allow the exclusion or limitation of *
> +* incidental or consequential damages, so this exclusion and *
> +* limitation may not apply to You. *
> +* *
> +************************************************************************
> +
> +8. Litigation
> +-------------
> +
> +Any litigation relating to this License may be brought only in the
> +courts of a jurisdiction where the defendant maintains its principal
> +place of business and such litigation shall be governed by laws of that
> +jurisdiction, without reference to its conflict-of-law provisions.
> +Nothing in this Section shall prevent a party's ability to bring
> +cross-claims or counter-claims.
> +
> +9. Miscellaneous
> +----------------
> +
> +This License represents the complete agreement concerning the subject
> +matter hereof. If any provision of this License is held to be
> +unenforceable, such provision shall be reformed only to the extent
> +necessary to make it enforceable. Any law or regulation which provides
> +that the language of a contract shall be construed against the drafter
> +shall not be used to construe this License against a Contributor.
> +
> +10. Versions of the License
> +---------------------------
> +
> +10.1. New Versions
> +
> +Mozilla Foundation is the license steward. Except as provided in Section
> +10.3, no one other than the license steward has the right to modify or
> +publish new versions of this License. Each version will be given a
> +distinguishing version number.
> +
> +10.2. Effect of New Versions
> +
> +You may distribute the Covered Software under the terms of the version
> +of the License under which You originally received the Covered Software,
> +or under the terms of any subsequent version published by the license
> +steward.
> +
> +10.3. Modified Versions
> +
> +If you create software not governed by this License, and you want to
> +create a new license for such software, you may create and use a
> +modified version of this License if you rename the license and remove
> +any references to the name of the license steward (except to note that
> +such modified license differs from this License).
> +
> +10.4. Distributing Source Code Form that is Incompatible With Secondary
> +Licenses
> +
> +If You choose to distribute Source Code Form that is Incompatible With
> +Secondary Licenses under the terms of this version of the License, the
> +notice described in Exhibit B of this License must be attached.
> +
> +Exhibit A - Source Code Form License Notice
> +-------------------------------------------
> +
> + This Source Code Form is subject to the terms of the Mozilla Public
> + License, v. 2.0. If a copy of the MPL was not distributed with this
> + file, You can obtain one at https://mozilla.org/MPL/2.0/.
> +
> +If it is not possible or desirable to put the notice in a particular
> +file, then You may include the notice in a location (such as a LICENSE
> +file in a relevant directory) where a recipient would be likely to look
> +for such a notice.
> +
> +You may add additional accurate notices of copyright ownership.
> +
> +Exhibit B - "Incompatible With Secondary Licenses" Notice
> +---------------------------------------------------------
> +
> + This Source Code Form is "Incompatible With Secondary Licenses", as
> + defined by the Mozilla Public License, v. 2.0.
> diff --git a/pkgs/default.nix b/pkgs/default.nix
> index bc25420..29fefb4 100644
> --- a/pkgs/default.nix
> +++ b/pkgs/default.nix
> @@ -36,6 +36,7 @@ let
> path: (import path { inherit (self) callPackage; }).override;
>
> rootfs = self.callSpectrumPackage ../host/rootfs {};
> + mount-flatpak = self.callSpectrumPackage ../tools/mount-flatpak {};
> spectrum-build-tools = self.callSpectrumPackage ../tools {
> appSupport = false;
> buildSupport = true;
> diff --git a/tools/mount-flatpak/Cargo.lock b/tools/mount-flatpak/Cargo.lock
> new file mode 100644
> index 0000000..8cb5663
> --- /dev/null
> +++ b/tools/mount-flatpak/Cargo.lock
> @@ -0,0 +1,238 @@
> +# This file is automatically @generated by Cargo.
> +# It is not intended for manual editing.
> +version = 4
> +
> +[[package]]
> +name = "bitflags"
> +version = "2.10.0"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "812e12b5285cc515a9c72a5c1d3b6d46a19dac5acfef5265968c166106e31dd3"
> +
> +[[package]]
> +name = "cfg-if"
> +version = "1.0.4"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
> +
> +[[package]]
> +name = "either"
> +version = "1.15.0"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "48c757948c5ede0e46177b7add2e67155f70e33c07fea8284df6576da70b3719"
> +
> +[[package]]
> +name = "errno"
> +version = "0.3.14"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "39cab71617ae0d63f51a36d69f866391735b51691dbda63cf6f96d042b63efeb"
> +dependencies = [
> + "libc",
> + "windows-sys",
> +]
> +
> +[[package]]
> +name = "fastrand"
> +version = "2.3.0"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "37909eebbb50d72f9059c3b6d82c0463f2ff062c9e95845c43a6c9c0355411be"
> +
> +[[package]]
> +name = "getrandom"
> +version = "0.3.4"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "899def5c37c4fd7b2664648c28120ecec138e4d395b459e5ca34f9cce2dd77fd"
> +dependencies = [
> + "cfg-if",
> + "libc",
> + "r-efi",
> + "wasip2",
> +]
> +
> +[[package]]
> +name = "itertools"
> +version = "0.14.0"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "2b192c782037fadd9cfa75548310488aabdbf3d2da73885b31bd0abd03351285"
> +dependencies = [
> + "either",
> +]
> +
> +[[package]]
> +name = "libc"
> +version = "0.2.177"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "2874a2af47a2325c2001a6e6fad9b16a53b802102b528163885171cf92b15976"
> +
> +[[package]]
> +name = "linux-raw-sys"
> +version = "0.11.0"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "df1d3c3b53da64cf5760482273a98e575c651a67eec7f77df96b5b642de8f039"
> +
> +[[package]]
> +name = "memchr"
> +version = "2.7.6"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "f52b00d39961fc5b2736ea853c9cc86238e165017a493d1d5c8eac6bdc4cc273"
> +
> +[[package]]
> +name = "mount-flatpak"
> +version = "0.0.0"
> +dependencies = [
> + "libc",
> + "pathrs",
> + "rustix",
> +]
> +
> +[[package]]
> +name = "once_cell"
> +version = "1.21.3"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "42f5e15c9953c5e4ccceeb2e7382a716482c34515315f7b03532b8b4e8393d2d"
> +
> +[[package]]
> +name = "pathrs"
> +version = "0.2.1"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "c63f58f2463b3eecc7d285eace144d8c4820631d018d927049f8569be4b3b1a4"
> +dependencies = [
> + "bitflags",
> + "itertools",
> + "libc",
> + "memchr",
> + "once_cell",
> + "rustix",
> + "rustversion",
> + "static_assertions",
> + "tempfile",
> + "thiserror",
> +]
> +
> +[[package]]
> +name = "proc-macro2"
> +version = "1.0.103"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "5ee95bc4ef87b8d5ba32e8b7714ccc834865276eab0aed5c9958d00ec45f49e8"
> +dependencies = [
> + "unicode-ident",
> +]
> +
> +[[package]]
> +name = "quote"
> +version = "1.0.42"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "a338cc41d27e6cc6dce6cefc13a0729dfbb81c262b1f519331575dd80ef3067f"
> +dependencies = [
> + "proc-macro2",
> +]
> +
> +[[package]]
> +name = "r-efi"
> +version = "5.3.0"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "69cdb34c158ceb288df11e18b4bd39de994f6657d83847bdffdbd7f346754b0f"
> +
> +[[package]]
> +name = "rustix"
> +version = "1.1.2"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "cd15f8a2c5551a84d56efdc1cd049089e409ac19a3072d5037a17fd70719ff3e"
> +dependencies = [
> + "bitflags",
> + "errno",
> + "libc",
> + "linux-raw-sys",
> + "windows-sys",
> +]
> +
> +[[package]]
> +name = "rustversion"
> +version = "1.0.22"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "b39cdef0fa800fc44525c84ccb54a029961a8215f9619753635a9c0d2538d46d"
> +
> +[[package]]
> +name = "static_assertions"
> +version = "1.1.0"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"
> +
> +[[package]]
> +name = "syn"
> +version = "2.0.111"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "390cc9a294ab71bdb1aa2e99d13be9c753cd2d7bd6560c77118597410c4d2e87"
> +dependencies = [
> + "proc-macro2",
> + "quote",
> + "unicode-ident",
> +]
> +
> +[[package]]
> +name = "tempfile"
> +version = "3.23.0"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "2d31c77bdf42a745371d260a26ca7163f1e0924b64afa0b688e61b5a9fa02f16"
> +dependencies = [
> + "fastrand",
> + "getrandom",
> + "once_cell",
> + "rustix",
> + "windows-sys",
> +]
> +
> +[[package]]
> +name = "thiserror"
> +version = "2.0.17"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "f63587ca0f12b72a0600bcba1d40081f830876000bb46dd2337a3051618f4fc8"
> +dependencies = [
> + "thiserror-impl",
> +]
> +
> +[[package]]
> +name = "thiserror-impl"
> +version = "2.0.17"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "3ff15c8ecd7de3849db632e14d18d2571fa09dfc5ed93479bc4485c7a517c913"
> +dependencies = [
> + "proc-macro2",
> + "quote",
> + "syn",
> +]
> +
> +[[package]]
> +name = "unicode-ident"
> +version = "1.0.22"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "9312f7c4f6ff9069b165498234ce8be658059c6728633667c526e27dc2cf1df5"
> +
> +[[package]]
> +name = "wasip2"
> +version = "1.0.1+wasi-0.2.4"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "0562428422c63773dad2c345a1882263bbf4d65cf3f42e90921f787ef5ad58e7"
> +dependencies = [
> + "wit-bindgen",
> +]
> +
> +[[package]]
> +name = "windows-link"
> +version = "0.2.1"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "f0805222e57f7521d6a62e36fa9163bc891acd422f971defe97d64e70d0a4fe5"
> +
> +[[package]]
> +name = "windows-sys"
> +version = "0.61.2"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "ae137229bcbd6cdf0f7b80a31df61766145077ddf49416a728b02cb3921ff3fc"
> +dependencies = [
> + "windows-link",
> +]
> +
> +[[package]]
> +name = "wit-bindgen"
> +version = "0.46.0"
> +source = "registry+https://github.com/rust-lang/crates.io-index"
> +checksum = "f17a85883d4e6d00e8a97c586de764dabcc06133f7f1d55dce5cdc070ad7fe59"
> diff --git a/tools/mount-flatpak/Cargo.lock.license b/tools/mount-flatpak/Cargo.lock.license
> new file mode 100644
> index 0000000..d705e97
> --- /dev/null
> +++ b/tools/mount-flatpak/Cargo.lock.license
> @@ -0,0 +1,2 @@
> +SPDX-License-Identifier: CC0-1.0
> +SPDX-FileCopyrightText: 2024 Alyssa Ross <hi@alyssa.is>
> diff --git a/tools/mount-flatpak/Cargo.toml b/tools/mount-flatpak/Cargo.toml
> new file mode 100644
> index 0000000..670be2f
> --- /dev/null
> +++ b/tools/mount-flatpak/Cargo.toml
> @@ -0,0 +1,11 @@
> +# SPDX-License-Identifier: CC0-1.0
> +# SPDX-FileCopyrightText: 2025 Alyssa Ross <hi@alyssa.is>
> +
> +[package]
> +name = "mount-flatpak"
> +edition = "2024"
> +
> +[dependencies]
> +libc = "0.2.177"
> +pathrs = "0.2.1"
> +rustix = "1.1.2"
> diff --git a/tools/mount-flatpak/config b/tools/mount-flatpak/config
> new file mode 100644
> index 0000000..b3c2bee
> --- /dev/null
> +++ b/tools/mount-flatpak/config
> @@ -0,0 +1,7 @@
> +# SPDX-License-Identifier: CC0-1.0
> +# SPDX-FileCopyrightText: 2025 Alyssa Ross <hi@alyssa.is>
> +
> +[core]
> +repo_version=1
> +mode=bare-user-only
> +min-free-space-size=500MB
> diff --git a/tools/mount-flatpak/default.nix b/tools/mount-flatpak/default.nix
> new file mode 100644
> index 0000000..f364fd7
> --- /dev/null
> +++ b/tools/mount-flatpak/default.nix
> @@ -0,0 +1,25 @@
> +# SPDX-FileCopyrightText: 2024-2025 Alyssa Ross <hi@alyssa.is>
> +# SPDX-License-Identifier: MIT
> +
> +import ../../lib/call-package.nix (
> +{ src, lib, rustPlatform }:
> +
> +rustPlatform.buildRustPackage {
> + name = "mount-flatpak";
> +
> + src = lib.fileset.toSource {
> + root = ../..;
> + fileset = lib.fileset.intersection src ./.;
> + };
> + sourceRoot = "source/tools/mount-flatpak";
> +
> + cargoLock.lockFile = ./Cargo.lock;
> +
> + env = {
> + MOUNT_FLATPAK_CONFIG_PATH = "${placeholder "out"}/share/spectrum/flatpak-config";
> + };
> +
> + postInstall = ''
> + install -Dm 0755 config $MOUNT_FLATPAK_CONFIG_PATH
> + '';
> +}) (_: {})
> diff --git a/tools/mount-flatpak/src/keyfile.rs b/tools/mount-flatpak/src/keyfile.rs
> new file mode 100644
> index 0000000..fa746b3
> --- /dev/null
> +++ b/tools/mount-flatpak/src/keyfile.rs
> @@ -0,0 +1,189 @@
> +// Copyright 2021 System76 <info@system76.com>
> +// SPDX-FileCopyrightText: 2025 Alyssa Ross <hi@alyssa.is>
> +// SPDX-License-Identifier: MPL-2.0
> +
> +// Adapted from freedesktop-desktop-entry 0.7.19.
> +
> +use std::collections::BTreeMap;
> +use std::fmt::{self, Display, Formatter};
> +
> +type Group = BTreeMap<String, String>;
> +
> +#[derive(Debug)]
> +pub enum DecodeError {
> + KeyValueWithoutAGroup,
> + InvalidKey,
> + InvalidValue,
> +}
> +
> +impl Display for DecodeError {
> + fn fmt(&self, f: &mut Formatter) -> fmt::Result {
> + match self {
> + Self::KeyValueWithoutAGroup => write!(f, "key/value without a group"),
> + Self::InvalidKey => write!(f, "invalid key"),
> + Self::InvalidValue => write!(f, "invalid value"),
> + }
> + }
> +}
> +
> +pub fn parse(input: &str) -> Result<BTreeMap<String, Group>, DecodeError> {
> + let mut groups = BTreeMap::default();
> + let mut active_group: Option<ActiveGroup> = None;
> + let mut active_keys: Option<ActiveKeys> = None;
> +
> + for line in input.lines() {
> + process_line(line, &mut groups, &mut active_group, &mut active_keys)?;
> + }
> +
> + if let Some(active_keys) = active_keys.take() {
> + match &mut active_group {
> + Some(active_group) => {
> + active_group
> + .group
> + .insert(active_keys.key_name, active_keys.value);
> + }
> + None => return Err(DecodeError::KeyValueWithoutAGroup),
> + }
> + }
> +
> + if let Some(mut group) = active_group.take() {
> + groups
> + .entry(group.group_name)
> + .or_default()
> + .append(&mut group.group);
> + }
> +
> + Ok(groups)
> +}
> +
> +struct ActiveGroup {
> + group_name: String,
> + group: Group,
> +}
> +
> +struct ActiveKeys {
> + key_name: String,
> + value: String,
> +}
> +
> +#[inline(never)]
> +fn process_line(
> + line: &str,
> + groups: &mut BTreeMap<String, Group>,
> + active_group: &mut Option<ActiveGroup>,
> + active_keys: &mut Option<ActiveKeys>,
> +) -> Result<(), DecodeError> {
> + if line.trim().is_empty() || line.starts_with('#') {
> + return Ok(());
> + }
> +
> + let line_bytes = line.as_bytes();
> +
> + // if group
> + if line_bytes[0] == b'[' {
> + if let Some(end) = line_bytes[1..].iter().rposition(|&b| b == b']') {
> + let group_name = &line[1..end + 1];
> +
> + if let Some(active_keys) = active_keys.take() {
> + match active_group {
> + Some(active_group) => {
> + active_group
> + .group
> + .insert(active_keys.key_name, active_keys.value);
> + }
> + None => return Err(DecodeError::KeyValueWithoutAGroup),
> + }
> + }
> +
> + if let Some(mut group) = active_group.take() {
> + groups
> + .entry(group.group_name)
> + .or_default()
> + .append(&mut group.group);
> + }
> +
> + active_group.replace(ActiveGroup {
> + group_name: group_name.to_string(),
> + group: Group::default(),
> + });
> + }
> + }
> + // else, if value
> + else if let Some(delimiter) = line_bytes.iter().position(|&b| b == b'=') {
> + let key = &line[..delimiter];
> + let value = format_value(&line[delimiter + 1..])?;
> +
> + if key.is_empty() {
> + return Err(DecodeError::InvalidKey);
> + }
> +
> + if let Some(active_keys) = active_keys.take() {
> + match active_group {
> + Some(active_group) => {
> + active_group
> + .group
> + .insert(active_keys.key_name, active_keys.value);
> + }
> + None => return Err(DecodeError::KeyValueWithoutAGroup),
> + }
> + }
> + active_keys.replace(ActiveKeys {
> + key_name: key.trim().to_string(),
> + value,
> + });
> + }
> + Ok(())
> +}
> +
> +// https://specifications.freedesktop.org/desktop-entry-spec/latest/value-types.html
> +#[inline]
> +fn format_value(input: &str) -> Result<String, DecodeError> {
> + let input = if let Some(input) = input.strip_prefix(" ") {
> + input
> + } else {
> + input
> + };
> +
> + let mut res = String::with_capacity(input.len());
> +
> + let mut last: usize = 0;
> +
> + for (i, v) in input.as_bytes().iter().enumerate() {
> + if *v != b'\\' {
> + continue;
> + }
> +
> + // edge case for //
> + if last > i {
> + continue;
> + }
> +
> + // when there is an \ at the end
> + if input.len() <= i + 1 {
> + return Err(DecodeError::InvalidValue);
> + }
> +
> + if last < i {
> + res.push_str(&input[last..i]);
> + }
> +
> + last = i + 2;
> +
> + match input.as_bytes()[i + 1] {
> + b's' => res.push(' '),
> + b'n' => res.push('\n'),
> + b't' => res.push('\t'),
> + b'r' => res.push('\r'),
> + b'\\' => res.push('\\'),
> + _ => {
> + return Err(DecodeError::InvalidValue);
> + }
> + }
> + }
> +
> + if last < input.len() {
> + res.push_str(&input[last..input.len()]);
> + }
> +
> + Ok(res)
> +}
> diff --git a/tools/mount-flatpak/src/main.rs b/tools/mount-flatpak/src/main.rs
> new file mode 100644
> index 0000000..db246cd
> --- /dev/null
> +++ b/tools/mount-flatpak/src/main.rs
> @@ -0,0 +1,296 @@
> +// SPDX-FileCopyrightText: 2025 Alyssa Ross <hi@alyssa.is>
> +// SPDX-License-Identifier: EUPL-1.2+
> +
> +//! Flatpak installations look like this:
> +//!
> +//! ```text
> +//! flatpak/
> +//! ├── app/
> +//! │ └── org.gnome.TextEditor/
> +//! │ ├── current -> x86_64/stable
> +//! │ └── x86_64/
> +//! │ └── stable/
> +//! │ ├── 0029140121b39f5b7cf4d44fd46b0708eee67f395b5e1291628612a0358fb909/
> +//! │ │ └── …
> +//! │ └── active -> 0029140121b39f5b7cf4d44fd46b0708eee67f395b5e1291628612a0358fb909
> +//! ├── db/
> +//! ├── exports/
> +//! │ └── …
> +//! ├── repo
> +//! │ ├── config
> +//! │ ├── objects
> +//! │ ├── tmp
> +//! │ │ └── cache
> +//! │ │ └── …
> +//! │ └── …
> +//! └── runtime
> +//! ├── org.gnome.Platform
> +//! │ └── x86_64
> +//! │ └── 49
> +//! │ ├── active -> bf6aa432cb310726f4ac0ec08cc88558619e1d4bd4b964e27e95187ecaad5400
> +//! │ └── bf6aa432cb310726f4ac0ec08cc88558619e1d4bd4b964e27e95187ecaad5400
> +//! │ └── …
> +//! └── …
> +//! ```
> +//!
> +//! The purpose of this program is to use bind mounts to construct a
> +//! Flatpak installation containing only a single application and
> +//! runtime, which can be passed through to a VM without exposing
> +//! other installed applications.
> +
> +mod keyfile;
> +mod metadata;
> +
> +use std::borrow::Cow;
> +use std::env::{ArgsOs, args_os};
> +use std::ffi::OsStr;
> +use std::io;
> +use std::os::unix::prelude::*;
> +use std::path::{Path, PathBuf};
> +use std::process::exit;
> +
> +use pathrs::Root;
> +use pathrs::flags::{OpenFlags, ResolverFlags};
> +use rustix::fs::{CWD, FileType, fstat};
> +use rustix::mount::{MoveMountFlags, OpenTreeFlags, move_mount, open_tree};
> +
> +use metadata::extract_runtime;
> +
> +fn ex_usage() -> ! {
> + eprintln!("Usage: mount-flatpak userdata installation app");
> + exit(1);
> +}
> +
> +fn run(mut args: ArgsOs) -> Result<(), String> {
> + let Some(user_data_path) = args.next().map(PathBuf::from) else {
> + ex_usage();
> + };
> + let Some(installation_path) = args.next().map(PathBuf::from) else {
> + ex_usage();
> + };
> + let Some(app) = args.next() else {
> + ex_usage();
> + };
> + if args.next().is_some() {
> + ex_usage();
> + }
> +
> + let mut user_data =
> + Root::open(&user_data_path).map_err(|e| format!("opening user data partition: {e}"))?;
> + user_data.set_resolver_flags(ResolverFlags::NO_SYMLINKS);
> +
> + let mut source_installation_dir = user_data
> + .open_subpath(&installation_path, OpenFlags::O_PATH)
> + .map(Root::from_fd)
> + .map_err(|e| format!("opening source flatpak installation: {e}"))?;
> + source_installation_dir.set_resolver_flags(ResolverFlags::NO_SYMLINKS);
> +
> + std::fs::create_dir("flatpak")
> + .map_err(|e| format!("creating target flatpak installation: {e}"))?;
> +
> + let target_installation_dir = open_tree(
> + CWD,
> + "flatpak",
> + OpenTreeFlags::OPEN_TREE_CLONE
> + | OpenTreeFlags::OPEN_TREE_CLOEXEC
> + | OpenTreeFlags::AT_RECURSIVE
> + | OpenTreeFlags::AT_SYMLINK_NOFOLLOW,
> + )
> + .map_err(|e| format!("opening target flatpak installation: {e}"))?;
> + let mut target_installation_dir = Root::from_fd(target_installation_dir);
> + target_installation_dir.set_resolver_flags(ResolverFlags::NO_SYMLINKS);
> +
> + let mut full_app_path = installation_path.join("app");
> + full_app_path.push(&app);
> + full_app_path.push("current");
> + let arch_and_branch = source_installation_dir
> + .readlink(&full_app_path)
> + .map_err(|e| format!("reading current app arch and branch: {e}"))?;
> + let mut components = arch_and_branch.components();
> + let arch = components.next().unwrap().as_os_str();
Should this return an error instead of panicking?
> + let branch = components.as_path().as_os_str();
> + if branch.is_empty() {
> + return Err("can't infer branch from \"current\" link".to_string());
> + }
Missing check that arch and branch are not empty, "." or "..", that
they do not exceed NAME_MAX (255) bytes, and do not contain '/'.
I would also check for NUL in case some weird filesystem image has it.
I will call this "path component validation" below.
> + full_app_path.pop();
> + full_app_path.push(&arch_and_branch);
> + full_app_path.push("active");
> + let commit = source_installation_dir
> + .readlink(&full_app_path)
> + .map_err(|e| format!("reading active app commit: {e}"))?
> + .into_os_string();
Missing path component validation.
> + full_app_path.pop();
> + full_app_path.push(&commit);
> + let source_app_dir = source_installation_dir
> + .resolve(&full_app_path)
> + .map_err(|e| format!("opening source app directory: {e}"))?;
> +
> + let metadata = source_installation_dir
> + .resolve(full_app_path.join("metadata"))
> + .map_err(|e| format!("resolving app metadata: {e}"))?;
> +
> + let metadata_stat =
> + fstat(&metadata).map_err(|e| format!("checking app metadata is a regular file: {e}"))?;
> + let metadata_type = FileType::from_raw_mode(metadata_stat.st_mode);
> + if !metadata_type.is_file() {
> + let e = format!("type of app metadata is {metadata_type:?}, not RegularFile");
> + return Err(e);
> + }
> + let metadata = metadata
> + .reopen(OpenFlags::O_RDONLY)
> + .map_err(|e| format!("opening app metadata: {e}"))?;
> +
> + let runtime =
> + extract_runtime(metadata).map_err(|e| format!("reading runtime from metadata: {e}"))?;
Missing check that there are 3 components. Missing validation of
each path component.
> + let mut full_runtime_path = installation_path.join("runtime");
> + full_runtime_path.push(runtime);
> + full_runtime_path.push("active");
> + let runtime_commit = source_installation_dir
> + .readlink(&full_runtime_path)
> + .map_err(|e| format!("reading active runtime commit: {e}"))?
> + .into_os_string();
Missing path component validation.
> + full_runtime_path.pop();
> + full_runtime_path.push(&runtime_commit);
> + let source_runtime_dir = source_installation_dir
> + .resolve(&full_runtime_path)
> + .map_err(|e| format!("opening source runtime directory: {e}"))?;
> +
> + let target_app_dir = target_installation_dir
> + .mkdir_all(&full_app_path, &PermissionsExt::from_mode(0o700))
> + .map_err(|e| format!("creating target app directory: {e}"))?;
> + let target_runtime_dir = target_installation_dir
> + .mkdir_all(&full_runtime_path, &PermissionsExt::from_mode(0o700))
> + .map_err(|e| format!("creating target runtime directory: {e}"))?;
> +
> + let source_app_tree = open_tree(
> + &source_app_dir,
> + "",
> + OpenTreeFlags::AT_EMPTY_PATH
> + | OpenTreeFlags::OPEN_TREE_CLONE
> + | OpenTreeFlags::OPEN_TREE_CLOEXEC
> + | OpenTreeFlags::AT_RECURSIVE,
> + )
> + .map_err(|e| format!("cloning source app tree: {e}"))?;
> + let source_runtime_tree = open_tree(
> + &source_runtime_dir,
> + "",
> + OpenTreeFlags::AT_EMPTY_PATH
> + | OpenTreeFlags::OPEN_TREE_CLONE
> + | OpenTreeFlags::OPEN_TREE_CLOEXEC
> + | OpenTreeFlags::AT_RECURSIVE,
> + )
> + .map_err(|e| format!("cloning source runtime tree: {e}"))?;
> + move_mount(
> + source_app_tree,
> + "",
> + target_app_dir,
> + "",
> + MoveMountFlags::MOVE_MOUNT_F_EMPTY_PATH | MoveMountFlags::MOVE_MOUNT_T_EMPTY_PATH,
> + )
> + .map_err(|e| format!("mounting app directory: {e}"))?;
> + move_mount(
> + source_runtime_tree,
> + "",
> + target_runtime_dir,
> + "",
> + MoveMountFlags::MOVE_MOUNT_F_EMPTY_PATH | MoveMountFlags::MOVE_MOUNT_T_EMPTY_PATH,
> + )
> + .map_err(|e| format!("mounting runtime directory: {e}"))?;
This code is all duplicated between the app and runtime directories.
I recommend using a common function for both.
> + target_installation_dir
> + .mkdir_all("repo/objects", &PermissionsExt::from_mode(0o700))
> + .map_err(|e| format!("creating repo/objects: {e}"))?;
> + target_installation_dir
> + .mkdir_all("repo/tmp/cache", &PermissionsExt::from_mode(0o700))
> + .map_err(|e| format!("creating repo/tmp/cache: {e}"))?;
> + let config_target = target_installation_dir
> + .create_file(
> + "repo/config",
> + OpenFlags::O_WRONLY | OpenFlags::O_CLOEXEC,
> + &PermissionsExt::from_mode(0o700),
> + )
> + .map_err(|e| format!("creating repo/config: {e}"))?;
> + let config_source_path = env!("MOUNT_FLATPAK_CONFIG_PATH");
> + let config_source = open_tree(
> + CWD,
> + config_source_path,
> + OpenTreeFlags::OPEN_TREE_CLONE | OpenTreeFlags::OPEN_TREE_CLOEXEC,
> + )
> + .map_err(|e| format!("opening {config_source_path}: {e}"))?;
> + move_mount(
> + config_source,
> + "",
> + config_target,
> + "",
> + MoveMountFlags::MOVE_MOUNT_F_EMPTY_PATH | MoveMountFlags::MOVE_MOUNT_T_EMPTY_PATH,
> + )
> + .map_err(|e| format!("mounting config: {e}"))?;
> +
> + let mut attr = libc::mount_attr {
> + attr_clr: libc::MOUNT_ATTR_NOSYMFOLLOW,
> + attr_set: libc::MOUNT_ATTR_RDONLY | libc::MOUNT_ATTR_NODEV,
> + propagation: libc::MS_SLAVE,
> + userns_fd: 0,
> + };
> + let empty = b"\0";
> + // SAFETY: we pass a valid FD, and a valid mutable pointer with the correct size.
Nit: extra comma. Also, there are other preconditions, like
‘empty’ being a valid C string.
> + unsafe {
> + let r = libc::syscall(
> + libc::SYS_mount_setattr,
> + target_installation_dir.as_fd().as_raw_fd() as libc::c_long,
> + empty.as_ptr() as *const libc::c_char,
> + (libc::AT_EMPTY_PATH | libc::AT_RECURSIVE) as libc::c_long,
> + &mut attr as *mut libc::mount_attr,
> + size_of::<libc::mount_attr>() as libc::c_long,
> + );
> + if r == -1 {
> + return Err(format!(
> + "setting target mount attributes: {}",
> + io::Error::last_os_error()
> + ));
> + }
> + }
> + move_mount(
> + target_installation_dir,
> + "",
> + CWD,
> + "flatpak",
> + MoveMountFlags::MOVE_MOUNT_F_EMPTY_PATH,
> + )
> + .map_err(|e| format!("mounting target installation dir: {e}"))?;
Is this really needed? It looks redundant. If it isn’t, I’d
add a comment explaining why.
> + std::fs::create_dir("params").map_err(|e| format!("creating params directory: {e}"))?;
> + std::fs::write("params/id", app.as_bytes()).map_err(|e| format!("writing params/id: {e}"))?;
> + std::fs::write("params/commit", commit.as_bytes())
> + .map_err(|e| format!("writing params/commit: {e}"))?;
> + std::fs::write("params/arch", arch.as_bytes())
> + .map_err(|e| format!("writing params/arch: {e}"))?;
> + std::fs::write("params/branch", branch.as_bytes())
> + .map_err(|e| format!("writing params/branch: {e}"))?;
> + std::fs::write("params/runtime-commit", runtime_commit.as_bytes())
> + .map_err(|e| format!("writing params/runtime-commit: {e}"))?;
> +
> + Ok(())
> +}
> +
> +fn main() {
> + let mut args = args_os();
> +
> + let prog_name = args
> + .next()
> + .as_ref()
> + .map(Path::new)
> + .and_then(Path::file_name)
> + .map_or(Cow::Borrowed("mount-flatpak"), OsStr::to_string_lossy)
> + .into_owned();
> +
> + if let Err(e) = run(args) {
> + eprintln!("{prog_name}: {e}");
> + exit(1);
> + }
> +}
> diff --git a/tools/mount-flatpak/src/metadata.rs b/tools/mount-flatpak/src/metadata.rs
> new file mode 100644
> index 0000000..dfc05b1
> --- /dev/null
> +++ b/tools/mount-flatpak/src/metadata.rs
> @@ -0,0 +1,19 @@
> +// SPDX-License-Identifier: EUPL-1.2+
> +// SPDX-FileCopyrightText: 2025 Alyssa Ross <hi@alyssa.is>
> +
> +use std::fs::File;
> +use std::io::read_to_string;
> +
> +use crate::keyfile::parse;
> +
> +pub fn extract_runtime(mut metadata: File) -> Result<String, String> {
> + let metadata = read_to_string(&mut metadata).map_err(|e| e.to_string())?;
> + let group = parse(&metadata).map_err(|e| e.to_string())?;
> + let application = group
> + .get("Application")
> + .ok_or_else(|| "Application group missing".to_string())?;
> + Ok(application
> + .get("runtime")
> + .ok_or_else(|| "runtime property missing".to_string())?
> + .clone())
> +}
I'd still add a limit for the amount of data that will be read.
Anything passed 128KiB is almost certainly a bug or attack. Forcing
OOM conditions is a useful attack primitive, as OOM errors may be
mishandled in various places.
Adding a cgroup is necessary, but having this code run in it isn't
trivial, as it isn't a supervised process.
--
Sincerely,
Demi Marie Obenour (she/her/hers)
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^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v4 5/5] host/rootfs: add run-flatpak script
2025-12-01 4:45 ` [PATCH v4 5/5] host/rootfs: add run-flatpak script Alyssa Ross
@ 2025-12-01 5:20 ` Demi Marie Obenour
2025-12-01 11:17 ` Alyssa Ross
0 siblings, 1 reply; 11+ messages in thread
From: Demi Marie Obenour @ 2025-12-01 5:20 UTC (permalink / raw)
To: Alyssa Ross, devel
[-- Attachment #1.1.1: Type: text/plain, Size: 4462 bytes --]
On 11/30/25 23:45, Alyssa Ross wrote:
> This is the entrypoint for running Flatpak applications.
>
> It would be good to only add mounts for the VM in virtiofsd's mount
> namespace, so we don't need to do lots of manual unmounts, but that's
> a wider change affecting more than just Flatpak.
>
> I've tested this by copying my host's Flatpak repository into a disk
> image, and attaching that as a drive to the VM.
>
> Signed-off-by: Alyssa Ross <hi@alyssa.is>
> ---
> v4: use the new VM mount namespace
> v3: https://spectrum-os.org/lists/archives/spectrum-devel/20251127202311.42422-7-hi@alyssa.is/
>
> host/rootfs/default.nix | 12 +++----
> host/rootfs/file-list.mk | 1 +
> host/rootfs/image/usr/bin/run-flatpak | 47 +++++++++++++++++++++++++++
> 3 files changed, 54 insertions(+), 6 deletions(-)
> create mode 100755 host/rootfs/image/usr/bin/run-flatpak
>
> diff --git a/host/rootfs/default.nix b/host/rootfs/default.nix
> index 57dd7a9..ca2084f 100644
> --- a/host/rootfs/default.nix
> +++ b/host/rootfs/default.nix
> @@ -12,9 +12,9 @@ pkgsMusl.callPackage (
> , lib, stdenvNoCC, nixos, runCommand, writeClosure, erofs-utils, s6-rc
> , btrfs-progs, busybox, cloud-hypervisor, cosmic-files, crosvm
> , cryptsetup, dejavu_fonts, dbus, execline, foot, fuse3, iproute2
> -, inotify-tools, jq, kmod, mdevd, mesa, s6, s6-linux-init, socat
> -, systemd, util-linuxMinimal, virtiofsd, westonLite
> -, xdg-desktop-portal, xdg-desktop-portal-gtk
> +, inotify-tools, jq, kmod, mdevd, mesa, mount-flatpak, s6
> +, s6-linux-init, socat, systemd, util-linuxMinimal, virtiofsd
> +, westonLite, xdg-desktop-portal, xdg-desktop-portal-gtk
> , xdg-desktop-portal-spectrum-host
> }:
>
> @@ -26,9 +26,9 @@ let
>
> packages = [
> btrfs-progs cloud-hypervisor cosmic-files crosvm cryptsetup dbus
> - execline fuse3 inotify-tools iproute2 jq kmod mdevd s6 s6-linux-init
> - s6-rc socat spectrum-host-tools spectrum-router util-linuxMinimal virtiofsd
> - xdg-desktop-portal-spectrum-host
> + execline fuse3 inotify-tools iproute2 jq kmod mdevd mount-flatpak s6
> + s6-linux-init s6-rc socat spectrum-host-tools spectrum-router
> + util-linuxMinimal virtiofsd xdg-desktop-portal-spectrum-host
>
> (foot.override { allowPgo = false; })
>
> diff --git a/host/rootfs/file-list.mk b/host/rootfs/file-list.mk
> index bfe3940..df22bce 100644
> --- a/host/rootfs/file-list.mk
> +++ b/host/rootfs/file-list.mk
> @@ -55,6 +55,7 @@ FILES = \
> image/usr/bin/assign-devices \
> image/usr/bin/create-vm-dependencies \
> image/usr/bin/run-appimage \
> + image/usr/bin/run-flatpak \
> image/usr/bin/run-vmm \
> image/usr/bin/spectrum-update \
> image/usr/bin/vm-console \
> diff --git a/host/rootfs/image/usr/bin/run-flatpak b/host/rootfs/image/usr/bin/run-flatpak
> new file mode 100755
> index 0000000..d7914a7
> --- /dev/null
> +++ b/host/rootfs/image/usr/bin/run-flatpak
> @@ -0,0 +1,47 @@
> +#!/bin/execlineb -W
> +# SPDX-License-Identifier: EUPL-1.2+
> +# 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 {
> + elgetpositionals
Serial substitution again! Should not be an issue as $id and $dir
should not contain ‘$’, but nicer to avoid.
You can use ‘elgetpositionals’ with ‘multisubstitute’ instead.
> + if { mkdir -p /run/configs/${id}/fs }
> +
> + if {
> + ln -s /usr/lib/spectrum/img/appvm/blk /usr/lib/spectrum/img/appvm/vmlinux
> + /run/configs/${id}
> + }
> +
> + 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 flatpak }
> + mount-flatpak $@
> + }
> +
> + piperw 4 3
> + background {
> + fdclose 3
> + fdmove 0 4
> +
> + # Wait for the VMM to be up, then start the VM.
> + if { redirfd -w 1 /dev/null head -1 }
> + vm-start $id
> + }
> + fdclose 4
> +
> + foreground { run-vmm $id }
> +}
> +
> +if { s6-instance-delete -- /run/service/vm-services $id }
> +
> +if { umount ${dir}/mount } # mount namespace
> +if { umount ${dir}/mount } # private bind mount
> +rm -r $dir /run/configs/${id}
--
Sincerely,
Demi Marie Obenour (she/her/hers)
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^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v4 5/5] host/rootfs: add run-flatpak script
2025-12-01 5:20 ` Demi Marie Obenour
@ 2025-12-01 11:17 ` Alyssa Ross
0 siblings, 0 replies; 11+ messages in thread
From: Alyssa Ross @ 2025-12-01 11:17 UTC (permalink / raw)
To: Demi Marie Obenour; +Cc: devel
[-- Attachment #1: Type: text/plain, Size: 3939 bytes --]
Demi Marie Obenour <demiobenour@gmail.com> writes:
> On 11/30/25 23:45, Alyssa Ross wrote:
>> This is the entrypoint for running Flatpak applications.
>>
>> It would be good to only add mounts for the VM in virtiofsd's mount
>> namespace, so we don't need to do lots of manual unmounts, but that's
>> a wider change affecting more than just Flatpak.
>>
>> I've tested this by copying my host's Flatpak repository into a disk
>> image, and attaching that as a drive to the VM.
>>
>> Signed-off-by: Alyssa Ross <hi@alyssa.is>
>> ---
>> v4: use the new VM mount namespace
>> v3: https://spectrum-os.org/lists/archives/spectrum-devel/20251127202311.42422-7-hi@alyssa.is/
>>
>> host/rootfs/default.nix | 12 +++----
>> host/rootfs/file-list.mk | 1 +
>> host/rootfs/image/usr/bin/run-flatpak | 47 +++++++++++++++++++++++++++
>> 3 files changed, 54 insertions(+), 6 deletions(-)
>> create mode 100755 host/rootfs/image/usr/bin/run-flatpak
>>
>> diff --git a/host/rootfs/default.nix b/host/rootfs/default.nix
>> index 57dd7a9..ca2084f 100644
>> --- a/host/rootfs/default.nix
>> +++ b/host/rootfs/default.nix
>> @@ -12,9 +12,9 @@ pkgsMusl.callPackage (
>> , lib, stdenvNoCC, nixos, runCommand, writeClosure, erofs-utils, s6-rc
>> , btrfs-progs, busybox, cloud-hypervisor, cosmic-files, crosvm
>> , cryptsetup, dejavu_fonts, dbus, execline, foot, fuse3, iproute2
>> -, inotify-tools, jq, kmod, mdevd, mesa, s6, s6-linux-init, socat
>> -, systemd, util-linuxMinimal, virtiofsd, westonLite
>> -, xdg-desktop-portal, xdg-desktop-portal-gtk
>> +, inotify-tools, jq, kmod, mdevd, mesa, mount-flatpak, s6
>> +, s6-linux-init, socat, systemd, util-linuxMinimal, virtiofsd
>> +, westonLite, xdg-desktop-portal, xdg-desktop-portal-gtk
>> , xdg-desktop-portal-spectrum-host
>> }:
>>
>> @@ -26,9 +26,9 @@ let
>>
>> packages = [
>> btrfs-progs cloud-hypervisor cosmic-files crosvm cryptsetup dbus
>> - execline fuse3 inotify-tools iproute2 jq kmod mdevd s6 s6-linux-init
>> - s6-rc socat spectrum-host-tools spectrum-router util-linuxMinimal virtiofsd
>> - xdg-desktop-portal-spectrum-host
>> + execline fuse3 inotify-tools iproute2 jq kmod mdevd mount-flatpak s6
>> + s6-linux-init s6-rc socat spectrum-host-tools spectrum-router
>> + util-linuxMinimal virtiofsd xdg-desktop-portal-spectrum-host
>>
>> (foot.override { allowPgo = false; })
>>
>> diff --git a/host/rootfs/file-list.mk b/host/rootfs/file-list.mk
>> index bfe3940..df22bce 100644
>> --- a/host/rootfs/file-list.mk
>> +++ b/host/rootfs/file-list.mk
>> @@ -55,6 +55,7 @@ FILES = \
>> image/usr/bin/assign-devices \
>> image/usr/bin/create-vm-dependencies \
>> image/usr/bin/run-appimage \
>> + image/usr/bin/run-flatpak \
>> image/usr/bin/run-vmm \
>> image/usr/bin/spectrum-update \
>> image/usr/bin/vm-console \
>> diff --git a/host/rootfs/image/usr/bin/run-flatpak b/host/rootfs/image/usr/bin/run-flatpak
>> new file mode 100755
>> index 0000000..d7914a7
>> --- /dev/null
>> +++ b/host/rootfs/image/usr/bin/run-flatpak
>> @@ -0,0 +1,47 @@
>> +#!/bin/execlineb -W
>> +# SPDX-License-Identifier: EUPL-1.2+
>> +# 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 {
>> + elgetpositionals
>
> Serial substitution again! Should not be an issue as $id and $dir
> should not contain ‘$’, but nicer to avoid.
Indeed. That's why I left dir and id, as previously discussed.
https://spectrum-os.org/lists/archives/spectrum-devel/87cy57311s.fsf@alyssa.is/
> You can use ‘elgetpositionals’ with ‘multisubstitute’ instead.
Not trivial to avoid serial substitution that way, as I'd also have to
lose the dir substitution or redefine it, and diverge from run-appimage
along the way.
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^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v4 3/5] tools/mount-flatpak: init
2025-12-01 5:14 ` Demi Marie Obenour
@ 2025-12-01 11:49 ` Alyssa Ross
0 siblings, 0 replies; 11+ messages in thread
From: Alyssa Ross @ 2025-12-01 11:49 UTC (permalink / raw)
To: Demi Marie Obenour; +Cc: devel
[-- Attachment #1: Type: text/plain, Size: 14271 bytes --]
Demi Marie Obenour <demiobenour@gmail.com> writes:
> On 11/30/25 23:45, Alyssa Ross wrote:
>> diff --git a/tools/mount-flatpak/src/main.rs b/tools/mount-flatpak/src/main.rs
>> new file mode 100644
>> index 0000000..db246cd
>> --- /dev/null
>> +++ b/tools/mount-flatpak/src/main.rs
>> @@ -0,0 +1,296 @@
>> +// SPDX-FileCopyrightText: 2025 Alyssa Ross <hi@alyssa.is>
>> +// SPDX-License-Identifier: EUPL-1.2+
>> +
>> +//! Flatpak installations look like this:
>> +//!
>> +//! ```text
>> +//! flatpak/
>> +//! ├── app/
>> +//! │ └── org.gnome.TextEditor/
>> +//! │ ├── current -> x86_64/stable
>> +//! │ └── x86_64/
>> +//! │ └── stable/
>> +//! │ ├── 0029140121b39f5b7cf4d44fd46b0708eee67f395b5e1291628612a0358fb909/
>> +//! │ │ └── …
>> +//! │ └── active -> 0029140121b39f5b7cf4d44fd46b0708eee67f395b5e1291628612a0358fb909
>> +//! ├── db/
>> +//! ├── exports/
>> +//! │ └── …
>> +//! ├── repo
>> +//! │ ├── config
>> +//! │ ├── objects
>> +//! │ ├── tmp
>> +//! │ │ └── cache
>> +//! │ │ └── …
>> +//! │ └── …
>> +//! └── runtime
>> +//! ├── org.gnome.Platform
>> +//! │ └── x86_64
>> +//! │ └── 49
>> +//! │ ├── active -> bf6aa432cb310726f4ac0ec08cc88558619e1d4bd4b964e27e95187ecaad5400
>> +//! │ └── bf6aa432cb310726f4ac0ec08cc88558619e1d4bd4b964e27e95187ecaad5400
>> +//! │ └── …
>> +//! └── …
>> +//! ```
>> +//!
>> +//! The purpose of this program is to use bind mounts to construct a
>> +//! Flatpak installation containing only a single application and
>> +//! runtime, which can be passed through to a VM without exposing
>> +//! other installed applications.
>> +
>> +mod keyfile;
>> +mod metadata;
>> +
>> +use std::borrow::Cow;
>> +use std::env::{ArgsOs, args_os};
>> +use std::ffi::OsStr;
>> +use std::io;
>> +use std::os::unix::prelude::*;
>> +use std::path::{Path, PathBuf};
>> +use std::process::exit;
>> +
>> +use pathrs::Root;
>> +use pathrs::flags::{OpenFlags, ResolverFlags};
>> +use rustix::fs::{CWD, FileType, fstat};
>> +use rustix::mount::{MoveMountFlags, OpenTreeFlags, move_mount, open_tree};
>> +
>> +use metadata::extract_runtime;
>> +
>> +fn ex_usage() -> ! {
>> + eprintln!("Usage: mount-flatpak userdata installation app");
>> + exit(1);
>> +}
>> +
>> +fn run(mut args: ArgsOs) -> Result<(), String> {
>> + let Some(user_data_path) = args.next().map(PathBuf::from) else {
>> + ex_usage();
>> + };
>> + let Some(installation_path) = args.next().map(PathBuf::from) else {
>> + ex_usage();
>> + };
>> + let Some(app) = args.next() else {
>> + ex_usage();
>> + };
>> + if args.next().is_some() {
>> + ex_usage();
>> + }
>> +
>> + let mut user_data =
>> + Root::open(&user_data_path).map_err(|e| format!("opening user data partition: {e}"))?;
>> + user_data.set_resolver_flags(ResolverFlags::NO_SYMLINKS);
>> +
>> + let mut source_installation_dir = user_data
>> + .open_subpath(&installation_path, OpenFlags::O_PATH)
>> + .map(Root::from_fd)
>> + .map_err(|e| format!("opening source flatpak installation: {e}"))?;
>> + source_installation_dir.set_resolver_flags(ResolverFlags::NO_SYMLINKS);
>> +
>> + std::fs::create_dir("flatpak")
>> + .map_err(|e| format!("creating target flatpak installation: {e}"))?;
>> +
>> + let target_installation_dir = open_tree(
>> + CWD,
>> + "flatpak",
>> + OpenTreeFlags::OPEN_TREE_CLONE
>> + | OpenTreeFlags::OPEN_TREE_CLOEXEC
>> + | OpenTreeFlags::AT_RECURSIVE
>> + | OpenTreeFlags::AT_SYMLINK_NOFOLLOW,
>> + )
>> + .map_err(|e| format!("opening target flatpak installation: {e}"))?;
>> + let mut target_installation_dir = Root::from_fd(target_installation_dir);
>> + target_installation_dir.set_resolver_flags(ResolverFlags::NO_SYMLINKS);
>> +
>> + let mut full_app_path = installation_path.join("app");
>> + full_app_path.push(&app);
>> + full_app_path.push("current");
>> + let arch_and_branch = source_installation_dir
>> + .readlink(&full_app_path)
>> + .map_err(|e| format!("reading current app arch and branch: {e}"))?;
>> + let mut components = arch_and_branch.components();
>> + let arch = components.next().unwrap().as_os_str();
>
> Should this return an error instead of panicking?
As far as I know a symlink target cannot contain 0 path components.
>> + let branch = components.as_path().as_os_str();
>> + if branch.is_empty() {
>> + return Err("can't infer branch from \"current\" link".to_string());
>> + }
>
> Missing check that arch and branch are not empty, "." or "..", that
> they do not exceed NAME_MAX (255) bytes, and do not contain '/'.
> I would also check for NUL in case some weird filesystem image has it.
>
> I will call this "path component validation" below.
We do not especially care if they are empty, exceed NAME_MAX bytes, or
contain ".", "..", "/" or even NUL. The security model here, as
previously explained[1], is that everything inside the Flatpak
repository is fair game, and that the pathrs::Root for the repository
ensures that nothing outside of it is accessed. The more redundant
validations we add on top of this, the more difficult the code is to
follow and maintain, and the more we're hardcoding brittle assumptions
about Flatpak's internal repository format. This also applies to your
further comments about path validation. I want systemic solutions where
it's not necessary to repeatedly make lots of easily-forgettable checks
to achieve safety.
[1]: https://spectrum-os.org/lists/archives/spectrum-devel/03b28aa9-c2fe-49d1-8f76-83240d85ae20@gmail.com/
>> + full_runtime_path.pop();
>> + full_runtime_path.push(&runtime_commit);
>> + let source_runtime_dir = source_installation_dir
>> + .resolve(&full_runtime_path)
>> + .map_err(|e| format!("opening source runtime directory: {e}"))?;
>> +
>> + let target_app_dir = target_installation_dir
>> + .mkdir_all(&full_app_path, &PermissionsExt::from_mode(0o700))
>> + .map_err(|e| format!("creating target app directory: {e}"))?;
>> + let target_runtime_dir = target_installation_dir
>> + .mkdir_all(&full_runtime_path, &PermissionsExt::from_mode(0o700))
>> + .map_err(|e| format!("creating target runtime directory: {e}"))?;
>> +
>> + let source_app_tree = open_tree(
>> + &source_app_dir,
>> + "",
>> + OpenTreeFlags::AT_EMPTY_PATH
>> + | OpenTreeFlags::OPEN_TREE_CLONE
>> + | OpenTreeFlags::OPEN_TREE_CLOEXEC
>> + | OpenTreeFlags::AT_RECURSIVE,
>> + )
>> + .map_err(|e| format!("cloning source app tree: {e}"))?;
>> + let source_runtime_tree = open_tree(
>> + &source_runtime_dir,
>> + "",
>> + OpenTreeFlags::AT_EMPTY_PATH
>> + | OpenTreeFlags::OPEN_TREE_CLONE
>> + | OpenTreeFlags::OPEN_TREE_CLOEXEC
>> + | OpenTreeFlags::AT_RECURSIVE,
>> + )
>> + .map_err(|e| format!("cloning source runtime tree: {e}"))?;
>> + move_mount(
>> + source_app_tree,
>> + "",
>> + target_app_dir,
>> + "",
>> + MoveMountFlags::MOVE_MOUNT_F_EMPTY_PATH | MoveMountFlags::MOVE_MOUNT_T_EMPTY_PATH,
>> + )
>> + .map_err(|e| format!("mounting app directory: {e}"))?;
>> + move_mount(
>> + source_runtime_tree,
>> + "",
>> + target_runtime_dir,
>> + "",
>> + MoveMountFlags::MOVE_MOUNT_F_EMPTY_PATH | MoveMountFlags::MOVE_MOUNT_T_EMPTY_PATH,
>> + )
>> + .map_err(|e| format!("mounting runtime directory: {e}"))?;
>
> This code is all duplicated between the app and runtime directories.
> I recommend using a common function for both.
I had that in C, but it didn't feel like a natural abstraction to me. I
can try it in Rust though and see if it's any different. It would be
nice not to have to repeat the open_tree(2) flags.
>> + target_installation_dir
>> + .mkdir_all("repo/objects", &PermissionsExt::from_mode(0o700))
>> + .map_err(|e| format!("creating repo/objects: {e}"))?;
>> + target_installation_dir
>> + .mkdir_all("repo/tmp/cache", &PermissionsExt::from_mode(0o700))
>> + .map_err(|e| format!("creating repo/tmp/cache: {e}"))?;
>> + let config_target = target_installation_dir
>> + .create_file(
>> + "repo/config",
>> + OpenFlags::O_WRONLY | OpenFlags::O_CLOEXEC,
>> + &PermissionsExt::from_mode(0o700),
>> + )
>> + .map_err(|e| format!("creating repo/config: {e}"))?;
>> + let config_source_path = env!("MOUNT_FLATPAK_CONFIG_PATH");
>> + let config_source = open_tree(
>> + CWD,
>> + config_source_path,
>> + OpenTreeFlags::OPEN_TREE_CLONE | OpenTreeFlags::OPEN_TREE_CLOEXEC,
>> + )
>> + .map_err(|e| format!("opening {config_source_path}: {e}"))?;
>> + move_mount(
>> + config_source,
>> + "",
>> + config_target,
>> + "",
>> + MoveMountFlags::MOVE_MOUNT_F_EMPTY_PATH | MoveMountFlags::MOVE_MOUNT_T_EMPTY_PATH,
>> + )
>> + .map_err(|e| format!("mounting config: {e}"))?;
>> +
>> + let mut attr = libc::mount_attr {
>> + attr_clr: libc::MOUNT_ATTR_NOSYMFOLLOW,
>> + attr_set: libc::MOUNT_ATTR_RDONLY | libc::MOUNT_ATTR_NODEV,
>> + propagation: libc::MS_SLAVE,
>> + userns_fd: 0,
>> + };
>> + let empty = b"\0";
>> + // SAFETY: we pass a valid FD, and a valid mutable pointer with the correct size.
>
> Nit: extra comma. Also, there are other preconditions, like
> ‘empty’ being a valid C string.
Yes, good point. Are there others? I suppose passing the correct
number of arguments with the correct types.
>> + unsafe {
>> + let r = libc::syscall(
>> + libc::SYS_mount_setattr,
>> + target_installation_dir.as_fd().as_raw_fd() as libc::c_long,
>> + empty.as_ptr() as *const libc::c_char,
>> + (libc::AT_EMPTY_PATH | libc::AT_RECURSIVE) as libc::c_long,
>> + &mut attr as *mut libc::mount_attr,
>> + size_of::<libc::mount_attr>() as libc::c_long,
>> + );
>> + if r == -1 {
>> + return Err(format!(
>> + "setting target mount attributes: {}",
>> + io::Error::last_os_error()
>> + ));
>> + }
>> + }
>> + move_mount(
>> + target_installation_dir,
>> + "",
>> + CWD,
>> + "flatpak",
>> + MoveMountFlags::MOVE_MOUNT_F_EMPTY_PATH,
>> + )
>> + .map_err(|e| format!("mounting target installation dir: {e}"))?;
>
> Is this really needed? It looks redundant. If it isn’t, I’d
> add a comment explaining why.
Is mounting the detached tree into the filesystem so it's actually
accesible really needed? Yes. I'm not sure how I could write a comment
making that clearer that wouldn't just be restating what the code says.
It's a textbook use of the new mount API.
>> + std::fs::create_dir("params").map_err(|e| format!("creating params directory: {e}"))?;
>> + std::fs::write("params/id", app.as_bytes()).map_err(|e| format!("writing params/id: {e}"))?;
>> + std::fs::write("params/commit", commit.as_bytes())
>> + .map_err(|e| format!("writing params/commit: {e}"))?;
>> + std::fs::write("params/arch", arch.as_bytes())
>> + .map_err(|e| format!("writing params/arch: {e}"))?;
>> + std::fs::write("params/branch", branch.as_bytes())
>> + .map_err(|e| format!("writing params/branch: {e}"))?;
>> + std::fs::write("params/runtime-commit", runtime_commit.as_bytes())
>> + .map_err(|e| format!("writing params/runtime-commit: {e}"))?;
>> +
>> + Ok(())
>> +}
>> +
>> +fn main() {
>> + let mut args = args_os();
>> +
>> + let prog_name = args
>> + .next()
>> + .as_ref()
>> + .map(Path::new)
>> + .and_then(Path::file_name)
>> + .map_or(Cow::Borrowed("mount-flatpak"), OsStr::to_string_lossy)
>> + .into_owned();
>> +
>> + if let Err(e) = run(args) {
>> + eprintln!("{prog_name}: {e}");
>> + exit(1);
>> + }
>> +}
>> diff --git a/tools/mount-flatpak/src/metadata.rs b/tools/mount-flatpak/src/metadata.rs
>> new file mode 100644
>> index 0000000..dfc05b1
>> --- /dev/null
>> +++ b/tools/mount-flatpak/src/metadata.rs
>> @@ -0,0 +1,19 @@
>> +// SPDX-License-Identifier: EUPL-1.2+
>> +// SPDX-FileCopyrightText: 2025 Alyssa Ross <hi@alyssa.is>
>> +
>> +use std::fs::File;
>> +use std::io::read_to_string;
>> +
>> +use crate::keyfile::parse;
>> +
>> +pub fn extract_runtime(mut metadata: File) -> Result<String, String> {
>> + let metadata = read_to_string(&mut metadata).map_err(|e| e.to_string())?;
>> + let group = parse(&metadata).map_err(|e| e.to_string())?;
>> + let application = group
>> + .get("Application")
>> + .ok_or_else(|| "Application group missing".to_string())?;
>> + Ok(application
>> + .get("runtime")
>> + .ok_or_else(|| "runtime property missing".to_string())?
>> + .clone())
>> +}
>
> I'd still add a limit for the amount of data that will be read.
> Anything passed 128KiB is almost certainly a bug or attack. Forcing
> OOM conditions is a useful attack primitive, as OOM errors may be
> mishandled in various places.
>
> Adding a cgroup is necessary, but having this code run in it isn't
> trivial, as it isn't a supervised process.
If we can't run non-supervised processes inside the cgroup we can't run
Cloud Hypervisor there, so we might as well not bother.
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^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH 2/5] host/rootfs: create a per-VM mount namespace
2025-12-01 4:52 ` Demi Marie Obenour
@ 2025-12-01 14:33 ` Alyssa Ross
0 siblings, 0 replies; 11+ messages in thread
From: Alyssa Ross @ 2025-12-01 14:33 UTC (permalink / raw)
To: Demi Marie Obenour; +Cc: devel
[-- Attachment #1: Type: text/plain, Size: 4379 bytes --]
Demi Marie Obenour <demiobenour@gmail.com> writes:
> On 11/30/25 23:45, Alyssa Ross wrote:
>> 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.
>
> Does the updater also need to be adjusted?
It does, thanks for pointing that out. We really need a test for it!
>> Signed-off-by: Alyssa Ross <hi@alyssa.is>
>> ---
>> .../template/data/service/dbus/run | 2 ++
>> .../template/data/service/vhost-user-fs/run | 4 +--
>> .../image/usr/bin/create-vm-dependencies | 23 ++++++++++++++---
>> host/rootfs/image/usr/bin/run-appimage | 25 +++++++++----------
>> 4 files changed, 34 insertions(+), 20 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..3848b0c 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
>> @@ -12,8 +12,6 @@ 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.
>
> Comment should be moved to the code that does the bind mount. Also,
> this comment is somewhat stale: the main reason to prevent writing
> into the toplevel fs/ folder is that host tools (like the updater)
> assume symlinks can't be created in it.
Good idea.
>> -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 ${VM}/fs
>> diff --git a/host/rootfs/image/usr/bin/create-vm-dependencies b/host/rootfs/image/usr/bin/create-vm-dependencies
>> index f3a1b69..21681cd 100755
>> --- a/host/rootfs/image/usr/bin/create-vm-dependencies
>> +++ b/host/rootfs/image/usr/bin/create-vm-dependencies
>> @@ -1,11 +1,26 @@
>> #!/bin/execlineb -S1
>> # SPDX-License-Identifier: EUPL-1.2+
>> -# SPDX-FileCopyrightText: 2024 Alyssa Ross <hi@alyssa.is>
>> +# SPDX-FileCopyrightText: 2024-2025 Alyssa Ross <hi@alyssa.is>
>>
>> -if { mount -m --rbind -o nofail /run/vm/by-id/${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 --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
> I would also create /run/vm/by-id/${1}/config/fs...
>
>> + }
>> +
>> + if { mount --make-shared --rbind /run/vm/by-id/${1} /run/vm/by-id/${1} }
>> +
>> + if { mount --rbind -o ro /run/vm/by-id/${1}/fs /run/vm/by-id/${1}/fs }
>
> VMs should not be able to write to their own config, so this and the
> next like should be swapped.
Makes sense.
>> + if { mount --rbind -o nofail /run/vm/by-id/${1}/config/fs /run/vm/by-id/${1}/fs/config }
>
> ...and remove this `-o nofail`.
Not sure about that, since config is likely to be on a different
filesystem we may not even be able to write to. Either way, it's out of
scope here, because it already works this way before this change.
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^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2025-12-01 14:34 UTC | newest]
Thread overview: 11+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-12-01 4:45 [PATCH 1/5] img/app: install fuse3 globally Alyssa Ross
2025-12-01 4:45 ` [PATCH 2/5] host/rootfs: create a per-VM mount namespace Alyssa Ross
2025-12-01 4:52 ` Demi Marie Obenour
2025-12-01 14:33 ` Alyssa Ross
2025-12-01 4:45 ` [PATCH v4 3/5] tools/mount-flatpak: init Alyssa Ross
2025-12-01 5:14 ` Demi Marie Obenour
2025-12-01 11:49 ` Alyssa Ross
2025-12-01 4:45 ` [PATCH v4 4/5] img/app: run Flatpak applications Alyssa Ross
2025-12-01 4:45 ` [PATCH v4 5/5] host/rootfs: add run-flatpak script Alyssa Ross
2025-12-01 5:20 ` Demi Marie Obenour
2025-12-01 11:17 ` Alyssa Ross
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