( )⚙ D1024 hgweb: do not import uuid immediately to avoid its side effect

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Differential D1024

hgweb: do not import uuid immediately to avoid its side effect
ClosedPublic

Authored by quark on Oct 12 2017, 1:02 AM.

Details

Reviewers
av6
Group Reviewers
hg-reviewers
Commits
rHGf42dec9c976e: hgweb: do not import uuid immediately to avoid its side effect
Summary

With hgdemandimport disabled (chg's case), import uuid has an immediate
side effect calling ctypes.util.find_library trying to locate the
libuuid library. This happens at import time before dispatch.run().
The call trace is like:

File "hg/hg", line 54, in <module>
  from mercurial import (
File "hg/mercurial/dispatch.py", line 24, in <module>
  from . import (
File "hg/mercurial/commands.py", line 23, in <module>
  from . import (
File "hg/mercurial/help.py", line 33, in <module>
  from .hgweb import (
File "hg/mercurial/hgweb/__init__.py", line 20, in <module>
  from . import (
File "hg/mercurial/hgweb/hgweb_mod.py", line 14, in <module>
  from .common import (
File "hg/mercurial/hgweb/common.py", line 15, in <module>
  import uuid
File "/usr/lib64/python2.7/uuid.py", line 404, in <module>
  lib = ctypes.CDLL(ctypes.util.find_library(libname))

The problem is, ctypes.util.find_library will execute
sh -c '/sbin/ldconfig -p 2>/dev/null' on Python <= 2.7.12. The output of
sh may pollute the terminal:

shell-init: error retrieving current directory: getcwd: cannot access
parent directories: No such file or directory

This patch moves import uuid so its side-effect can only happen after the
cwd check in dispatch._getlocal. Therefore the terminal won't be
polluted by importing uuid.

Diff Detail

Repository
rHG Mercurial
Lint
Automatic diff as part of commit; lint not applicable.
Unit
Automatic diff as part of commit; unit tests not applicable.

Event Timeline

quark created this revision.Oct 12 2017, 1:02 AM
quark updated this revision to Diff 2613.Oct 12 2017, 1:04 AM
av6 accepted this revision.Oct 12 2017, 7:16 AM
This revision is now accepted and ready to land.Oct 12 2017, 7:16 AM
yuja added a subscriber: yuja.Oct 13 2017, 9:39 AM
yuja added inline comments.
tests/test-dispatch.t
64

Replaced with #if rmcwd

Closed by commit rHGf42dec9c976e: hgweb: do not import uuid immediately to avoid its side effect (authored by quark). · Explain WhyOct 13 2017, 10:06 AM
This revision was automatically updated to reflect the committed changes.

Revision Contents
Changeset List

PathPackages
Mmercurial/hgweb/common.py (18 lines)
Mtests/test-dispatch.t (13 lines)

Diff 2681

mercurial/hgweb/common.py

# hgweb/common.py - Utility functions needed by hgweb_mod and hgwebdir_mod # hgweb/common.py - Utility functions needed by hgweb_mod and hgwebdir_mod
# #
# Copyright 21 May 2005 - (c) 2005 Jake Edge <jake@edge2.net> # Copyright 21 May 2005 - (c) 2005 Jake Edge <jake@edge2.net>
# Copyright 2005, 2006 Matt Mackall <mpm@selenic.com> # Copyright 2005, 2006 Matt Mackall <mpm@selenic.com>
# #
# This software may be used and distributed according to the terms of the # This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version. # GNU General Public License version 2 or any later version.
from __future__ import absolute_import from __future__ import absolute_import
import base64 import base64
import errno import errno
import mimetypes import mimetypes
import os import os
import uuid
from .. import ( from .. import (
encoding, encoding,
pycompat, pycompat,
util, util,
) )
httpserver = util.httpserver httpserver = util.httpserver
def cspvalues(ui): def cspvalues(ui):
"""Obtain the Content-Security-Policy header and nonce value. """Obtain the Content-Security-Policy header and nonce value.
Returns a 2-tuple of the CSP header value and the nonce value. Returns a 2-tuple of the CSP header value and the nonce value.
First value is ``None`` if CSP isn't enabled. Second value is ``None`` First value is ``None`` if CSP isn't enabled. Second value is ``None``
if CSP isn't enabled or if the CSP header doesn't need a nonce. if CSP isn't enabled or if the CSP header doesn't need a nonce.
""" """
# Without demandimport, "import uuid" could have an immediate side-effect
# running "ldconfig" on Linux trying to find libuuid.
# With Python <= 2.7.12, that "ldconfig" is run via a shell and the shell
# may pollute the terminal with:
#
# shell-init: error retrieving current directory: getcwd: cannot access
# parent directories: No such file or directory
#
# Python >= 2.7.13 has fixed it by running "ldconfig" directly without a
# shell (hg changeset a09ae70f3489).
#
# Moved "import uuid" from here so it's executed after we know we have
# a sane cwd (i.e. after dispatch.py cwd check).
#
# We can move it back once we no longer need Python <= 2.7.12 support.
import uuid
# Don't allow untrusted CSP setting since it be disable protections # Don't allow untrusted CSP setting since it be disable protections
# from a trusted/global source. # from a trusted/global source.
csp = ui.config('web', 'csp', untrusted=False) csp = ui.config('web', 'csp', untrusted=False)
nonce = None nonce = None
if csp and '%nonce%' in csp: if csp and '%nonce%' in csp:
nonce = base64.urlsafe_b64encode(uuid.uuid4().bytes).rstrip('=') nonce = base64.urlsafe_b64encode(uuid.uuid4().bytes).rstrip('=')
csp = csp.replace('%nonce%', nonce) csp = csp.replace('%nonce%', nonce)
return csp, nonce return csp, nonce

tests/test-dispatch.t

No repo: No repo:
$ hg cat $ hg cat
abort: no repository found in '$TESTTMP' (.hg not found)! abort: no repository found in '$TESTTMP' (.hg not found)!
[255] [255]
#endif #endif
#if rmcwd
yujaUnsubmitted
Not Done

Replaced with #if rmcwd

yuja: Replaced with `#if rmcwd`
Current directory removed:
$ mkdir $TESTTMP/repo1
$ cd $TESTTMP/repo1
$ rm -rf $TESTTMP/repo1
$ HGDEMANDIMPORT=disable hg version -q
abort: error getting current working directory: * (glob)
[255]
#endif