mkimage: --user content fill (keeps GPT)

tools/mkimage.py

@@ -70,12 +70,19 @@ def gpt_header(nent, lba_backup, disk_guid, crc_entries, cur=1):
 
 
 def main():
-    out = sys.argv[1] if len(sys.argv) > 1 else "images/emmc.img"
+    out = sys.argv[-1] if not sys.argv[-1].startswith("-") else "images/emmc.img"
+    user_src = None
+    if "--user" in sys.argv:
+        user_src = sys.argv[sys.argv.index("--user") + 1]
     pre = (BOOT_MB * 2 + RPMB_MB) * 1024 * 1024
     total = FILE_SIZE
     assert pre + USER_SECTORS * SECTOR <= total
     print(f"[mkimage] {out}: boot {BOOT_MB}M x2 + rpmb {RPMB_MB}M + "
-          f"user {USER_SECTORS} sectors")
+          f"user {USER_SECTORS} sectors" +
+          (f" + content {user_src}" if user_src else " (zero)"))
+    with open(out, "wb") as f:
+        f.truncate(total)  # sparse
+        uoff = pre
     with open(out, "wb") as f:
         f.truncate(total)  # sparse
         uoff = pre
@@ -106,6 +113,19 @@ def main():
         f.seek(uoff + (USER_SECTORS - 1) * SECTOR)
         f.write(gpt_header(128, 1, disk, crc_e,
                            cur=USER_SECTORS - 1))
+    if user_src:
+        print(f"[mkimage] copying User content (keeps GPT in place)...")
+        with open(user_src, "rb") as u:
+            # copy in 128M chunks, skipping GPT areas (LBA 0..33, backup)
+            u.seek(34 * SECTOR)
+            f.seek(uoff + 34 * SECTOR)
+            left = (USER_SECTORS - 33) * SECTOR - 34 * SECTOR
+            while left > 0:
+                d = u.read(min(left, 134217728))
+                if not d:
+                    break
+                f.write(d)
+                left -= len(d)
     print(f"[mkimage] OK: {len(PARTS)} partitions, primary+backup GPT, CRC ok")