From 5d26338bb36087b6300e856791aa0bac12e765c8 Mon Sep 17 00:00:00 2001
From: Kroese <kroese@users.noreply.github.com>
Date: Thu, 16 Jul 2026 21:41:29 +0200
Subject: [PATCH] feat: Improve detection of valid data disk (#1275)

---
 src/utils.sh | 68 +++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 60 insertions(+), 8 deletions(-)

diff --git a/src/utils.sh b/src/utils.sh
index 4769147..06763fa 100644
--- a/src/utils.sh
+++ b/src/utils.sh
@@ -415,22 +415,74 @@ cpu() {
   return 0
 }
 
-hasDisk() {
+getDisk() {
 
+  local name="${DISK_NAME:-data}" path
   enabled "${DISK_DISABLE:-}" && return 1
 
-  [ -b "/disk" ] && return 0
-  [ -b "/disk1" ] && return 0
-  [ -b "/dev/disk1" ] && return 0
-  [ -b "${DEVICE:-}" ] && return 0
+  for path in "/disk" "/disk1" "/dev/disk1" "${DEVICE:-}"; do
+    if [ -n "$path" ] && [ -b "$path" ]; then
+      printf '%s\n' "$path"
+      return 0
+    fi
+  done
 
-  [ -z "${DISK_NAME:-}" ] && DISK_NAME="data"
-  [ -s "$STORAGE/$DISK_NAME.img" ]  && return 0
-  [ -s "$STORAGE/$DISK_NAME.qcow2" ] && return 0
+  for path in "$STORAGE/$name.img" "$STORAGE/$name.qcow2"; do
+    if [ -s "$path" ]; then
+      printf '%s\n' "$path"
+      return 0
+    fi
+  done
 
   return 1
 }
 
+hasDisk() {
+
+  getDisk >/dev/null
+  return $?
+
+}
+
+hasData() {
+
+  local path
+  local rc=0 tmp=""
+  local bytes=102400
+
+  path=$(getDisk) || return 1
+  local source="$path"
+
+  if [[ "${path,,}" == *.qcow2 ]]; then
+
+    tmp=$(mktemp) || {
+      warn "failed to create a temporary file while inspecting \"$path\"."
+      return 0
+    }
+
+    if ! qemu-img dd -f qcow2 -O raw bs="$bytes" count=1 \
+        "if=$path" "of=$tmp" >/dev/null 2>&1; then
+      rm -f "$tmp"
+      warn "failed to inspect disk \"$path\", assuming it contains data."
+      return 0
+    fi
+
+    source="$tmp"
+
+  fi
+
+  cmp -s -n "$bytes" "$source" /dev/zero || rc=$?
+  [ -n "$tmp" ] && rm -f "$tmp"
+
+  case "$rc" in
+    0) return 1 ;;
+    1) return 0 ;;
+  esac
+
+  warn "failed to inspect disk \"$path\", assuming it contains data."
+  return 0
+}
+
 getCountry() {
 
   local url=$1