[elbe-devel] [PATCH v2 5/7] Prevent double file access

[Bastian Germann]

Windows locks an open file. Prevent files that are open from being
opened again on the client side.

To that end, eliminate the use of NamedTemporaryFile with .name
access.

Signed-off-by: Bastian Germann <bage at linutronix.de>
---
 elbepack/initvmaction.py  | 13 ++++++-------
 elbepack/xmlpreprocess.py | 25 ++++++++++++++++---------
 2 files changed, 22 insertions(+), 16 deletions(-)

diff --git a/elbepack/initvmaction.py b/elbepack/initvmaction.py
index af153de8fc..44df1b1674 100644
--- a/elbepack/initvmaction.py
+++ b/elbepack/initvmaction.py
@@ -13,8 +13,6 @@ import time
 import os
 import datetime
 
-from tempfile import NamedTemporaryFile
-
 import elbepack
 from elbepack.treeutils import etree
 from elbepack.directories import elbe_exe
@@ -266,16 +264,17 @@ class AttachAction(InitVMAction):
 
 
 def submit_with_repodir_and_dl_result(xmlfile, cdrom, opt):
+    fname = f'elbe-repodir-{time.time_ns()}.xml'
+    preprocess_xmlfile = os.path.join(os.path.dirname(xmlfile), fname)
     try:
-        with NamedTemporaryFile(suffix=".xml", prefix="elbe-repodir",
-                dir=os.path.dirname(xmlfile)) as tmpfile:
-            preprocess_xmlfile = tmpfile.name
-            with Repodir(xmlfile, preprocess_xmlfile):
-                submit_and_dl_result(preprocess_xmlfile, cdrom, opt)
+        with Repodir(xmlfile, preprocess_xmlfile):
+            submit_and_dl_result(preprocess_xmlfile, cdrom, opt)
     except RepodirError as err:
         print("elbe repodir failed", file=sys.stderr)
         print(err, file=sys.stderr)
         sys.exit(20)
+    finally:
+        os.remove(preprocess_xmlfile)
 
 
 def submit_and_dl_result(xmlfile, cdrom, opt):
diff --git a/elbepack/xmlpreprocess.py b/elbepack/xmlpreprocess.py
index 86a913b309..8481abdd55 100644
--- a/elbepack/xmlpreprocess.py
+++ b/elbepack/xmlpreprocess.py
@@ -8,8 +8,9 @@
 import os
 import re
 import sys
+import tempfile
+import time
 
-from tempfile import NamedTemporaryFile
 from optparse import OptionGroup
 from itertools import islice
 from urllib.error import HTTPError,URLError
@@ -17,7 +18,7 @@ from urllib.request import urlopen
 from passlib.hash import sha512_crypt
 
 from lxml import etree
-from lxml.etree import XMLParser, parse, Element
+from lxml.etree import XMLParser, Element
 
 from elbepack.archivedir import ArchivedirError, combinearchivedir
 from elbepack.config import cfg
@@ -272,7 +273,12 @@ def preprocess_passwd(xml):
         adduser.attrib['passwd_hashed'] = sha512_crypt.hash(passwd)
         del adduser.attrib['passwd']
 
-def xmlpreprocess(fname, output, variants=None, proxy=None):
+def xmlpreprocess(xml_input_file, xml_output_file, variants=None, proxy=None):
+    """Preprocesses the input XML data to make sure the `output`
+       can be validated against the current schema.
+       `xml_input_file` is either a file-like object or a path (str) to the input file.
+       `xml_output_file` is either a file-like object or a path (str) to the output file.
+    """
 
     # pylint: disable=too-many-locals
     # pylint: disable=too-many-branches
@@ -289,7 +295,7 @@ def xmlpreprocess(fname, output, variants=None, proxy=None):
     schema = etree.XMLSchema(schema_tree)
 
     try:
-        xml = parse(fname, parser=parser)
+        xml = etree.parse(xml_input_file, parser=parser)
         xml.xinclude()
 
         # Variant management
@@ -360,7 +366,7 @@ def xmlpreprocess(fname, output, variants=None, proxy=None):
         if schema.validate(xml):
             # if validation succedes write xml file
             xml.write(
-                output,
+                xml_output_file,
                 encoding="UTF-8",
                 pretty_print=True,
                 compression=9)
@@ -390,10 +396,11 @@ class PreprocessWrapper:
             self.options += f' --variants "{opt.variant}"'
 
     def __enter__(self):
-        self.outxml = NamedTemporaryFile(prefix='elbe', suffix='xml')
+        fname = f'elbe-{time.time_ns()}.xml'
+        self.outxml = os.path.join(tempfile.gettempdir(), fname)
 
         cmd = (f'{sys.executable} {elbe_exe} preprocess {self.options} '
-               f'-o {self.outxml.name} {self.xmlfile}')
+               f'-o {self.outxml} {self.xmlfile}')
         ret, _, err = command_out_stderr(cmd)
         if ret != 0:
             print("elbe preprocess failed.", file=sys.stderr)
@@ -403,7 +410,7 @@ class PreprocessWrapper:
         return self
 
     def __exit__(self, _typ, _value, _traceback):
-        self.outxml = None
+        os.remove(self.outxml)
 
     @staticmethod
     def add_options(oparser):
@@ -420,4 +427,4 @@ class PreprocessWrapper:
 
     @property
     def preproc(self):
-        return self.outxml.name
+        return self.outxml
-- 
2.30.2