fix(import-payload): detect payload strictly from /proc/partitions major/minor

steps/improve/import_payload.sh

@@ -8,33 +8,37 @@ set -ex
 if [ "${PAYLOAD_REQUIRED}" = True ]; then
     mkdir -p /external/distfiles
     found_payload=0
+    mkdir -p /dev
 
-    if [ -r /proc/partitions ]; then
+    if [ ! -r /proc/partitions ]; then
-        while read -r major minor blocks name; do
+        echo "payload-import failed: /proc/partitions is unavailable." >&2
-            case "${name}" in
+        exit 1
-                ""|name|ram*|loop*|fd*|sr*|md*|dm-*|nbd*)
-                    continue
-                    ;;
-                *[0-9])
-                    continue
-                    ;;
-            esac
-            dev_path="/dev/${name}"
-            [ -b "${dev_path}" ] || mknod -m 600 "${dev_path}" b "${major}" "${minor}" >/dev/null 2>&1 || :
-        done < /proc/partitions
     fi
 
-    for dev_path in /dev/*; do
+    while read -r major minor blocks name; do
-        [ -b "${dev_path}" ] || continue
+        case "${major}" in
-        if payload-import --probe "${dev_path}"; then
+            ""|major|*[!0-9]*)
+                continue
+                ;;
+        esac
+        case "${minor}" in
+            ""|minor|*[!0-9]*)
+                continue
+                ;;
+        esac
+
+        dev_path="/dev/lbpayload-${major}-${minor}"
+        [ -b "${dev_path}" ] || mknod -m 600 "${dev_path}" b "${major}" "${minor}" >/dev/null 2>&1 || :
+
+        if payload-import --probe "${dev_path}" >/dev/null 2>&1; then
             payload-import --device "${dev_path}" /external/distfiles
             found_payload=1
             break
         fi
-    done
+    done < /proc/partitions
 
     if [ "${found_payload}" != 1 ]; then
-        echo "payload-import failed: no payload image found on block devices under /dev." >&2
+        echo "payload-import failed: no payload image found in /proc/partitions devices." >&2
         exit 1
     fi
 fi