osbuild: split package into separate files

Import modules between files using the syntax `from . import foobar`,
renaming what used to be `FooBar` to `foobar.FooBar` when moved to a
separate file.

In __init__.py only import what is meant to be public API.

Signed-off-by: Tom Gundersen <teg@jklm.no>

osbuild/tmpfs.py

@@ -0,0 +1,36 @@
+
+import os
+import subprocess
+import tempfile
+
+
+__all__ = [
+    "TmpFs",
+]
+
+
+class TmpFs:
+    def __init__(self, path="/run/osbuild"):
+        self.path = path
+        self.root = None
+        self.mounted = False
+
+    def __enter__(self):
+        self.root = tempfile.mkdtemp(prefix="osbuild-tmpfs-", dir=self.path)
+        try:
+            subprocess.run(["mount", "-t", "tmpfs", "-o", "mode=0755", "tmpfs", self.root], check=True)
+            self.mounted = True
+        except subprocess.CalledProcessError:
+            os.rmdir(self.root)
+            self.root = None
+            raise
+        return self.root
+
+    def __exit__(self, exc_type, exc_value, exc_tb):
+        if not self.root:
+            return
+        if self.mounted:
+            subprocess.run(["umount", "--lazy", self.root], check=True)
+            self.mounted = False
+        os.rmdir(self.root)
+        self.root = None