Fix git-llvm crashing when trying to remove directory while cleaning

[teemperor]

Summary

I'm trying to push D59198 but it seems that git-llvm push can't handle the fact
that I add a new directory in the patch:

> git llvm push -n
Pushing 1 commit:
  e7c0a9bd136 Correctly look up declarations in inline namespaces
Traceback (most recent call last):
  File "llvm/utils/git-svn//git-llvm", line 431, in <module>
    args.func(args)
  File "llvm/utils/git-svn//git-llvm", line 385, in cmd_push
    clean_svn(svn_root)
  File "llvm/utils/git-svn//git-llvm", line 201, in clean_svn
    os.remove(os.path.join(svn_repo, filename))
IsADirectoryError: [Errno 21] Is a directory: '.git/llvm-upstream-svn/lldb/trunk/packages/Python/lldbsuite/test/expression_command/inline-namespace'

This patch just uses shutil to delete the directory instead of trying to use os.remove
which only works for files.

[jlebar]

Thanks!

[jlebar]

Actually, I wonder if we should have some protections built in here, because e.g. if filename contains "/../../" we could end up rm'ing an arbitrary directory on the machine.

This was true before too, but now it's particularly scary that we're doing rmtree.

We could compute the absolute path to svn_repo and the absolute path to join(svn_repo, filename) and ensure that the first is a prefix of the second?

[teemperor]

• Added safety check that we don't delete directories or files outside the llvm staging dir.

[jlebar]

That is much less scary! Thanks.

llvm/trunk/utils/git-svn/git-llvm

 
 from __future__ import print_function
 import argparse
 import collections
 import contextlib
 import errno
 import os
 import re
+import shutil
 import subprocess
 import sys
 import tempfile
 import time
 assert sys.version_info >= (2, 7)
 
 try:
     dict.iteritems
def clean_svn(svn_repo):
     svn(svn_repo, 'revert', '-R', '.')
 
     # Unfortunately it appears there's no svn equivalent for git clean, so we
     # have to do it ourselves.
     for line in svn(svn_repo, 'status', '--no-ignore').split('\n'):
         if not line.startswith('?'):
             continue
         filename = line[1:].strip()
-        os.remove(os.path.join(svn_repo, filename))
+        filepath = os.path.abspath(os.path.join(svn_repo, filename))
+        abs_svn_repo = os.path.abspath(svn_repo)
+        # Safety check that the directory we are about to delete is
+        # actually within our svn staging dir.
+        if not filepath.startswith(abs_svn_repo):
+            die("Path to clean (%s) is not in svn staging dir (%s)"
+                % (filepath, abs_svn_repo))
+
+        if os.path.isdir(filepath):
+            shutil.rmtree(filepath)
+        else:
+            os.remove(filepath)
 
 
 def svn_init(svn_root):
     if not os.path.exists(svn_root):
         log('Creating svn staging directory: (%s)' % (svn_root))
         os.makedirs(svn_root)
         svn(svn_root, 'checkout', '--depth=empty',
             'https://llvm.org/svn/llvm-project/', '.')