[New-bugs-announce] [issue16946] subprocess: _close_open_fd_range_safe() does not set close-on-exec flag on Linux < 2.6.23 if O_CLOEXEC is defined

[STINNER Victor]

New submission from STINNER Victor:

The following extract of _close_open_fd_range_safe() is not correct:

#ifdef O_CLOEXEC
    fd_dir_fd = open(FD_DIR, O_RDONLY | O_CLOEXEC, 0);
#else
    fd_dir_fd = open(FD_DIR, O_RDONLY, 0);
#ifdef FD_CLOEXEC
    {
        int old = fcntl(fd_dir_fd, F_GETFD);
        if (old != -1)
            fcntl(fd_dir_fd, F_SETFD, old | FD_CLOEXEC);
    }
#endif
#endif

On Linux older than 2.6.23, O_CLOEXEC may be defined by the glibc whereas the kernel does not support it. In this case, the flag is simply ignored and close-on-exec flag is not set on the file descriptor.

----------
messages: 179803
nosy: haypo, neologix
priority: normal
severity: normal
status: open
title: subprocess: _close_open_fd_range_safe() does not set close-on-exec flag on Linux < 2.6.23 if O_CLOEXEC is defined
versions: Python 3.2, Python 3.3, Python 3.4

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue16946>
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