pmb: add -f (force) parameter to bootimg_analyze

We are analyzing the `boot.img` with `file` before we send it to
`unpackbootimg`. File does not recognize all kinds of `boot.img` files,
which `unpackbootimg` can extract, so we need a way to skip this check.

Details:
* Add `-f` parameter, continues extraction with a warning if the file
  seems to be invalid
* Tell the user that `-f` can be used if the `boot.img` is invalid and
  it's not specified
* Consistent spelling of `boot.img` instead of `bootimg` in messages

Fixes #1608

pmb/parse/arguments.py

@@ -437,6 +437,9 @@ def arguments():
     bootimg_analyze = sub.add_parser("bootimg_analyze", help="Extract all the"
                                      " information from an existing boot.img")
     bootimg_analyze.add_argument("path", help="path to the boot.img")
+    bootimg_analyze.add_argument("-f", dest="force", action="store_true",
+                                 help="force even if the file seems to be"
+                                      " invalid")
 
     # Use defaults from the user's config file
     args = parser.parse_args()

pmb/parse/bootimg.py

@@ -38,12 +38,22 @@ def bootimg(args, path):
     file_output = pmb.chroot.user(args, ["file", "-b", "boot.img"], working_dir=temp_path,
                                   return_stdout=True).rstrip()
     if "android bootimg" not in file_output.lower():
-        if "linux kernel" in file_output.lower():
-            raise RuntimeError("File is a Kernel image, you might need the 'heimdall-isorec'"
-                               " flash method. See also: "
-                               "<https://wiki.postmarketos.org/wiki/Deviceinfo_flash_methods>")
+        if "force" in args and args.force:
+            logging.warning("WARNING: boot.img file seems to be invalid, but"
+                            " proceeding anyway (-f specified)")
         else:
-            raise RuntimeError("File is not an Android bootimg. (" + file_output + ")")
+            logging.info("NOTE: If you are sure that your file is a valid"
+                         " boot.img file, you could force the analysis"
+                         " with: 'pmbootstrap bootimg_analyze " + path +
+                         " -f'")
+            if "linux kernel" in file_output.lower():
+                raise RuntimeError("File is a Kernel image, you might need the"
+                                   " 'heimdall-isorec' flash method. See also:"
+                                   " <https://wiki.postmarketos.org/wiki/"
+                                   "Deviceinfo_flash_methods>")
+            else:
+                raise RuntimeError("File is not an Android boot.img. (" +
+                                   file_output + ")")
 
     # Extract all the files
     pmb.chroot.user(args, ["unpackbootimg", "-i", "boot.img"], working_dir=temp_path)

test/test_bootimg.py

@@ -56,7 +56,7 @@ def test_bootimg_kernel(args):
 def test_bootimg_invalid_file(args):
     with pytest.raises(RuntimeError) as e:
         pmb.parse.bootimg(args, __file__)
-    assert "File is not an Android bootimg" in str(e.value)
+    assert "File is not an Android boot.img" in str(e.value)
 
 
 def test_bootimg_normal(args):