From 5399e1d4633e43e522185e2113018a5482ff11ab Mon Sep 17 00:00:00 2001
From: Kroese <kroese@users.noreply.github.com>
Date: Sat, 18 Jul 2026 11:31:20 +0200
Subject: [PATCH] feat: Use Unix sockets for qemu-host communication (#1299)

---
 docs/environment.md |  2 --
 src/power.sh        |  7 ++++---
 src/print.sh        |  5 +++--
 src/serial.sh       | 41 +++++++++++++++++++++++++++--------------
 src/server.sh       |  4 ----
 5 files changed, 34 insertions(+), 25 deletions(-)

diff --git a/docs/environment.md b/docs/environment.md
index 028a4dc..743fb7f 100644
--- a/docs/environment.md
+++ b/docs/environment.md
@@ -95,6 +95,4 @@ An empty default means the variable is unset and its value is determined automat
 |---|---|---|
 | `DEBUG` | `N` | Enables verbose debug output. |
 | `TRACE` | `N` | Enables shell command tracing. |
-| `COM_PORT` | `2210` | Internal communication port used by the DSM host helper. |
-| `CHR_PORT` | `12345` | Internal character device port used by the DSM host helper. |
 | `HOST_DEBUG` | `N` | Enables debug output for the DSM host helper. |
diff --git a/src/power.sh b/src/power.sh
index 222e861..8c8b216 100644
--- a/src/power.sh
+++ b/src/power.sh
@@ -8,7 +8,6 @@ set -Eeuo pipefail
 # Configure QEMU for graceful shutdown
 
 API_CMD=6
-API_HOST="127.0.0.1:$COM_PORT"
 
 SHUTDOWN_SKIP=0
 SHUTDOWN_SIGNAL=0
@@ -98,6 +97,8 @@ cleanupHelpers() {
   mKill "${pids[@]}"
   fKill "print.sh"
 
+  rm -f -- "$HOST_API_SOCKET" "$HOST_AGENT_SOCKET"
+
   closeNetwork
   return 0
 }
@@ -191,8 +192,8 @@ sendGuestShutdown() {
 
   # Send shutdown command to guest agent via serial port
   API_TIMEOUT=$(strip "$API_TIMEOUT")
-  url="http://$API_HOST/read?command=$API_CMD&timeout=$API_TIMEOUT"
-  response=$(curl -sk -m "$(( API_TIMEOUT+2 ))" -S "$url" 2>&1)
+  url="http://localhost/read?command=$API_CMD&timeout=$API_TIMEOUT"
+  response=$(curl --unix-socket "$HOST_API_SOCKET" -sk -m "$(( API_TIMEOUT+2 ))" -S "$url" 2>&1)
 
   if [[ "$response" =~ "\"success\"" ]]; then
 
diff --git a/src/print.sh b/src/print.sh
index 03621f5..3b2f502 100644
--- a/src/print.sh
+++ b/src/print.sh
@@ -19,8 +19,9 @@ driver="/run/shm/qemu.nic"
 page="/run/shm/index.html"
 address="/run/shm/qemu.ip"
 shutdown="/run/shm/qemu.end"
+socket="/run/shm/qemu-host-api.sock"
 template="/var/www/index.html"
-url="http://127.0.0.1:2210/read?command=10"
+url="http://localhost/read?command=10"
 
 resp_err="Guest returned an invalid response:"
 curl_err="Failed to connect to guest: curl error"
@@ -37,7 +38,7 @@ queryGuest() {
 
   local rc
 
-  { json=$(curl -m 20 -sk "$url"); rc=$?; } || :
+  { json=$(curl --unix-socket "$socket" -m 20 -sk "$url"); rc=$?; } || :
 
   exitIfShuttingDown
 
diff --git a/src/serial.sh b/src/serial.sh
index 5a2a078..7ea3ddc 100644
--- a/src/serial.sh
+++ b/src/serial.sh
@@ -15,6 +15,10 @@ HOST_MODEL=$(strip "$HOST_MODEL")
 HOST_SERIAL=$(strip "$HOST_SERIAL")
 GUEST_SERIAL=$(strip "$GUEST_SERIAL")
 
+HOST_PID="$QEMU_DIR/host.pid"
+HOST_API_SOCKET="$QEMU_DIR/qemu-host-api.sock"
+HOST_AGENT_SOCKET="$QEMU_DIR/qemu-host-agent.sock"
+
 validateHostMac() {
   local m
 
@@ -41,6 +45,8 @@ buildHostArguments() {
   HOST_ARGS=()
   HOST_ARGS+=("-cpu=$CPU_CORES")
   HOST_ARGS+=("-cpu_arch=$HOST_CPU")
+  HOST_ARGS+=("-api=$HOST_API_SOCKET")
+  HOST_ARGS+=("-addr=$HOST_AGENT_SOCKET")
 
   [ -n "$HOST_MAC" ] && HOST_ARGS+=("-mac=$HOST_MAC")
   [ -n "$HOST_MODEL" ] && HOST_ARGS+=("-model=$HOST_MODEL")
@@ -54,6 +60,8 @@ startHostBinary() {
 
   local pid
 
+  rm -f -- "$HOST_PID" "$HOST_API_SOCKET" "$HOST_AGENT_SOCKET" || return 1
+
   if enabled "$HOST_DEBUG"; then
     set -x
     ./host.bin "${HOST_ARGS[@]}" &
@@ -70,17 +78,27 @@ startHostBinary() {
   return 0
 }
 
+waitForSocket() {
 
-waitForPort() {
-
-  local port="$1"
+  local socket="$1"
   local exit_code="$2"
-  local cnt=0
+  local pid cnt=0
+
+  while [ ! -S "$socket" ]; do
+
+    if ! read -r pid < "$HOST_PID" || ! isAlive "$pid"; then
+      error "qemu-host exited unexpectedly!"
+      exit "$exit_code"
+    fi
 
-  while ! nc -z -w2 127.0.0.1 "$port" > /dev/null 2>&1; do
     sleep 0.1
     cnt=$((cnt + 1))
-    (( cnt > 50 )) && error "Failed to connect to qemu-host.." && exit "$exit_code"
+
+    if (( cnt > 50 )); then
+      error "Failed to create qemu-host socket: $socket"
+      exit "$exit_code"
+    fi
+
   done
 
   return 0
@@ -106,24 +124,19 @@ configureSerialPorts() {
 
   SERIAL_OPTS+=" \
         -device virtio-serial-pci,id=virtio-serial0,bus=pcie.0,addr=0x3 \
-        -chardev socket,id=charchannel0,host=127.0.0.1,port=$CHR_PORT,reconnect=10 \
+        -chardev socket,id=charchannel0,path=$HOST_AGENT_SOCKET,reconnect-ms=1000 \
         -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=vchannel"
 
   return 0
-
 }
 
 validateHostMac
 
-HOST_PID="$QEMU_DIR/host.pid"
-
 buildHostArguments
 startHostBinary
 
-sleep 0.2
-
-waitForPort "$COM_PORT" 58
-waitForPort "$CHR_PORT" 59
+waitForSocket "$HOST_API_SOCKET" 58
+waitForSocket "$HOST_AGENT_SOCKET" 59
 
 configureSerialPorts
 
diff --git a/src/server.sh b/src/server.sh
index ab1034a..508156e 100644
--- a/src/server.sh
+++ b/src/server.sh
@@ -1,15 +1,11 @@
 #!/usr/bin/env bash
 set -Eeuo pipefail
 
-: "${COM_PORT:="2210"}"    # Comm port
 : "${WEB_PORT:="5000"}"    # Webserver port
-: "${CHR_PORT:="12345"}"   # Character port
 : "${WSD_PORT:="8004"}"    # Websockets port
 
 # Sanitize port variables
-COM_PORT=$(strip "$COM_PORT")
 WEB_PORT=$(strip "$WEB_PORT")
-CHR_PORT=$(strip "$CHR_PORT")
 WSD_PORT=$(strip "$WSD_PORT")
 
 WEB_PID="/run/nginx.pid"