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James Stringer
45285394d9
appsandbox-display / -audio / -input installed SIGINT/SIGTERM via signal(), which on glibc carries BSD SA_RESTART semantics. With the listen socket blocking and no SO_RCVTIMEO, a SIGTERM at poweroff ran the handler (set g_stop=1) but the kernel auto-restarted the blocking accept() instead of returning EINTR — so the existing `if (errno == EINTR) continue;` re-check never fired and the daemon sat blocked in accept(). systemd then waited the full TimeoutStopSec (~90s) per unit before SIGKILL, which presented as the VM hanging at shutdown. Reconnecting the IDD display made accept() return a real connection, the loop re-evaluated g_stop, and shutdown finally completed — the tell. Switch all three to sigaction() with sa_flags=0 (no SA_RESTART), exactly matching appsandbox-agent.c, which already shuts down promptly for this reason. accept() now returns EINTR on SIGTERM and the loop exits cleanly.
App Sandbox Linux guest daemons
In-VM Linux daemons that speak the same vsock wire protocol the Windows
App Sandbox host expects. See docs/linux-idd-implementation-plan.md in
the repo root for full architecture and wire-protocol reference.
Daemons (this directory)
| Binary | Channel | Listens on | Privilege | Status |
|---|---|---|---|---|
appsandbox-agent |
control | vsock :1 | root (system) | implemented |
appsandbox-input |
input | vsock :3 | root (system) | planned |
appsandbox-display |
frames + cursor | vsock :2 | root (system) | planned |
appsandbox-clipboard |
clipboard | vsock :5, :6 | user (user unit) | planned |
Build (inside the VM)
sudo apt-get install -y build-essential
make
Install + enable (inside the VM)
sudo make enable
This installs to /usr/local/bin/, drops the systemd unit into
/etc/systemd/system/, runs daemon-reload, then
systemctl enable --now appsandbox-agent.service.
Smoke test
systemctl status appsandbox-agent
journalctl -u appsandbox-agent -f
You should see listening on AF_VSOCK port 1. Once the host-side Phase 1
service-GUID switch lands, the App Sandbox UI's agent dot will turn green
within a few seconds of the unit being active.
Uninstall
sudo make disable
sudo rm /usr/local/bin/appsandbox-agent /etc/systemd/system/appsandbox-agent.service
sudo systemctl daemon-reload