fix(payload-import): remove mount(8) dependency and import by kernel-enumerated block devices via /proc/partitions

steps/improve/import_payload.sh

@@ -7,41 +7,8 @@ set -ex
 
 if [ "${PAYLOAD_REQUIRED}" = True ]; then
     mkdir -p /external/distfiles
-    mkdir -p /proc
-
-    # Reliable enumeration in Fiwix: mount procfs and read /proc/partitions.
-    if [ ! -r /proc/partitions ]; then
-        mount -t proc proc /proc
-    fi
-    if [ ! -r /proc/partitions ]; then
-        echo "payload-import failed: /proc/partitions is unavailable." >&2
-        exit 1
-    fi
-
-    found_payload=0
-    while read -r major minor blocks name; do
-        case "${name}" in
-            ""|name|ram*|loop*|fd*|sr*|md*|dm-*|nbd*)
-                continue
-                ;;
-            *[0-9])
-                # Skip partitions (hda1, sdb2, ...); payload is a whole disk.
-                continue
-                ;;
-        esac
-
-        dev_path="/dev/${name}"
-        [ -b "${dev_path}" ] || mknod -m 600 "${dev_path}" b "${major}" "${minor}"
-
-        if payload-import --probe "${dev_path}"; then
-            payload-import --device "${dev_path}" /external/distfiles
-            found_payload=1
-            break
-        fi
-    done < /proc/partitions
-
-    if [ "${found_payload}" != 1 ]; then
-        echo "payload-import failed: no payload image found in /proc/partitions." >&2
+    if ! payload-import /external/distfiles; then
+        echo "payload-import failed: no payload image found on block devices." >&2
         exit 1
     fi
 fi