Qubes: avoid tracebacks when no more /tmp storage

Detect OSError when writing RBG files on the Qubes isolation provider.

Fixes #578

Author: deeplow

dangerzone/conversion/errors.py

@@ -124,6 +124,15 @@ class ServerOutOfTempSpaceError(OutOfSpaceError):
     error_message = "The isolated environment where the document conversion take space ran out of space"
 
 
+class ClientOutOfTMPSpaceError(OutOfSpaceError):
+    """The client ran out of space"""
+
+    error_code = ERROR_SHIFT + 72
+    error_message = (
+        "You computer ran out of temporary storage space during the document conversion"
+    )
+
+
 class UnexpectedConversionError(PDFtoPPMException):
     error_code = ERROR_SHIFT + 100
     error_message = "Some unexpected error occurred while converting the document"

dangerzone/isolation_provider/qubes.py

@@ -135,14 +135,16 @@ def __convert(
                     timeout=sw.remaining,
                 )
 
-                # Wrapper code
-                with open(f"/tmp/dangerzone/page-{page}.width", "w") as f_width:
-                    f_width.write(str(width))
-                with open(f"/tmp/dangerzone/page-{page}.height", "w") as f_height:
-                    f_height.write(str(height))
-                with open(f"/tmp/dangerzone/page-{page}.rgb", "wb") as f_rgb:
-                    f_rgb.write(untrusted_pixels)
-
+                try:
+                    # Wrapper code
+                    with open(f"/tmp/dangerzone/page-{page}.width", "w") as f_width:
+                        f_width.write(str(width))
+                    with open(f"/tmp/dangerzone/page-{page}.height", "w") as f_height:
+                        f_height.write(str(height))
+                    with open(f"/tmp/dangerzone/page-{page}.rgb", "wb") as f_rgb:
+                        f_rgb.write(untrusted_pixels)
+                except OSError:
+                    raise errors.ClientOutOfTMPSpaceError()
                 percentage += percentage_per_page
 
                 text = f"Converting page {page}/{n_pages} to pixels"