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os.dup() creates an inheritable fd when handling a character file on Windows #81448

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ZackerySpytz mannequin opened this issue Jun 13, 2019 · 8 comments
Closed

os.dup() creates an inheritable fd when handling a character file on Windows #81448

ZackerySpytz mannequin opened this issue Jun 13, 2019 · 8 comments
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3.7 (EOL) end of life 3.8 only security fixes 3.9 only security fixes extension-modules C modules in the Modules dir OS-windows type-bug An unexpected behavior, bug, or error

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@ZackerySpytz
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ZackerySpytz mannequin commented Jun 13, 2019

BPO 37267
Nosy @pfmoore, @vstinner, @tjguk, @zware, @zooba, @MojoVampire, @ZackerySpytz
PRs
  • bpo-37267: Do not check for FILE_TYPE_CHAR in os.dup() on Windows #14051
  • [3.8] bpo-37267: Do not check for FILE_TYPE_CHAR in os.dup() on Windows (GH-14051) #14140
  • [3.7] bpo-37267: Do not check for FILE_TYPE_CHAR in os.dup() on Windows (GH-14051) #14141
  • Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.

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    GitHub fields:

    assignee = None
    closed_at = <Date 2019-06-17.08:49:27.884>
    created_at = <Date 2019-06-13.10:12:30.664>
    labels = ['type-bug', '3.8', '3.9', 'extension-modules', '3.7', 'OS-windows']
    title = 'os.dup() creates an inheritable fd when handling a character file on Windows'
    updated_at = <Date 2019-07-10.18:43:06.815>
    user = 'https://github.com/ZackerySpytz'

    bugs.python.org fields:

    activity = <Date 2019-07-10.18:43:06.815>
    actor = 'josh.r'
    assignee = 'none'
    closed = True
    closed_date = <Date 2019-06-17.08:49:27.884>
    closer = 'vstinner'
    components = ['Extension Modules', 'Windows']
    creation = <Date 2019-06-13.10:12:30.664>
    creator = 'ZackerySpytz'
    dependencies = []
    files = []
    hgrepos = []
    issue_num = 37267
    keywords = ['patch']
    message_count = 8.0
    messages = ['345494', '345513', '345799', '345800', '345824', '345825', '345827', '347633']
    nosy_count = 7.0
    nosy_names = ['paul.moore', 'vstinner', 'tim.golden', 'zach.ware', 'steve.dower', 'josh.r', 'ZackerySpytz']
    pr_nums = ['14051', '14140', '14141']
    priority = 'normal'
    resolution = 'fixed'
    stage = 'resolved'
    status = 'closed'
    superseder = None
    type = 'behavior'
    url = 'https://bugs.python.org/issue37267'
    versions = ['Python 3.7', 'Python 3.8', 'Python 3.9']

    @ZackerySpytz
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    ZackerySpytz mannequin commented Jun 13, 2019

    In PR 13739, Eryk Sun mentioned that the Windows implementation of os.dup() returns an inheritable fd when handling a character file. A comment in _Py_dup() makes it seem as though this is due to a belief that handles for character files cannot be made non-inheritable (which is wrong).

    @ZackerySpytz ZackerySpytz mannequin added 3.7 (EOL) end of life 3.8 only security fixes 3.9 only security fixes extension-modules C modules in the Modules dir OS-windows type-bug An unexpected behavior, bug, or error labels Jun 13, 2019
    @vstinner
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    If you care of inherited handles on Windows, please have a look at:

    ref: https://pythondev.readthedocs.io/unstable_tests.html#windows-handles

    I decided to give up because of multiprocessing race conditions. I failed to fix them.

    @vstinner
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    New changeset 28fca0c by Victor Stinner (Zackery Spytz) in branch 'master':
    bpo-37267: Do not check for FILE_TYPE_CHAR in os.dup() on Windows (GH-14051)
    28fca0c

    @vstinner
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    According to the discussion in PR 14051: if os.dup() fails to make the new file descriptor new inheritable for a character device, the error must not be ignored. Instead, the caller is supposed to use os.dup(fd, inheritable=False).

    Before *this bugfix*, os.dup() didn't respect its contract: fd2 was inheritable sometimes. Now the caller is aware of such special case and so can handle it properly.

    @vstinner
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    New changeset 7158949 by Victor Stinner (Miss Islington (bot)) in branch '3.7':
    bpo-37267: Do not check for FILE_TYPE_CHAR in os.dup() on Windows (GH-14051) (GH-14141)
    7158949

    @vstinner
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    New changeset 693945d by Victor Stinner (Miss Islington (bot)) in branch '3.8':
    bpo-37267: Do not check for FILE_TYPE_CHAR in os.dup() on Windows (GH-14051) (GH-14140)
    693945d

    @vstinner
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    Thanks Zackery Spytz as usual!

    @MojoVampire
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    MojoVampire mannequin commented Jul 10, 2019

    This may have caused a regression, see bpo-37549.

    @ezio-melotti ezio-melotti transferred this issue from another repository Apr 10, 2022
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