Added -o OUTPUT_DIR argument

README.md

@@ -23,8 +23,9 @@ positional arguments:
   filename    Android kernel image
 
 optional arguments:
-  -h, --help  show this help message and exit
-  -n          Do not extract, just output information
+  -h, --help     show this help message and exit
+  -o OUTPUT_DIR  Output directory
+  -n             Do not extract, just output information
 ```
 
 Example:
@@ -33,10 +34,10 @@ Example:
 $ ./extract-dtb.py -n vmlinuz-motorola-titan
 Found 8 appended dtbs
 
-$ ./extract-dtb.py vmlinuz-motorola-titan
+$ ./extract-dtb.py vmlinuz-motorola-titan -o /tmp/dtb
 Extracted 8 appended dtbs + kernel
 
-$ ls -l
+$ ls -l /tmp/dtb
 total 8808
 -rw-rw-r-- 1 pablo pablo  194829 jun 25 17:14 dtbdump_1.dtb
 -rw-rw-r-- 1 pablo pablo  194829 jun 25 17:14 dtbdump_2.dtb

extract-dtb.py

@@ -18,7 +18,7 @@
 """
 
 import argparse
-import sys
+import os
 
 DTB_HEADER = b"\xd0\x0d\xfe\xed"
 
@@ -45,23 +45,27 @@ def split(args):
         return
 
     if args.extract:
+        os.makedirs(args.output_dir, exist_ok=True)
         last_pos = 0
         for n, pos in enumerate(pos_dtb, 0):
             dtb_filename = "dtbdump_{0}.dtb".format(n) if n != 0 else "kernel"
-            dump_file(dtb_filename, content[last_pos:pos])
+            dump_file(os.path.join(args.output_dir, dtb_filename), content[last_pos:pos])
             last_pos = pos
 
         # Last chunk
         dtb_filename = "dtbdump_{0}.dtb".format(n)
-        dump_file(dtb_filename, content[last_pos:])
-        print("Extracted {0} appended dtbs + kernel".format(len(pos_dtb) - 1))
+        dump_file(os.path.join(args.output_dir, dtb_filename), content[last_pos:])
+        print("Extracted {0} appended dtbs + kernel to {1}"
+              .format(len(pos_dtb) - 1, args.output_dir))
     else:
         print("Found {0} appended dtbs".format(len(pos_dtb) - 1))
 
 
 if __name__ == "__main__":
     parser = argparse.ArgumentParser(description="Extract dtbs from kernel images.")
     parser.add_argument("filename", help="Android kernel image")
+    parser.add_argument("-o", dest="output_dir", default="dtb",
+                        required=False, help="Output directory")
     parser.add_argument("-n", dest="extract", action="store_false", default=True,
                         required=False, help="Do not extract, just output information")
     args = parser.parse_args()