bug#37884: 27.0.50; Cannot write to a file in VirtualBox shared directory

[Robert Pluim]

>>>>> On Wed, 30 Oct 2019 18:41:10 -0700, Paul Eggert <eggert@cs.ucla.edu> said:

    Paul> On 10/30/19 9:25 AM, Eli Zaretskii wrote:
    >> Paul, do you
    >> see any downsides to the last change posted in this discussion?  IOW,
    >> could there be some situations where it could do any harm?

    Paul> That change involves two extra system calls (one of which doesn't
    Paul> check the return value?!).

I donʼt know what value there would be in checking the return value of
chmod, given that weʼre already in an error situation.

    Paul> In contrast, Bernardo's suggestion is
    Paul> simpler, involves no extra system calls (or machine instructions, for
    Paul> that matter), and has been tested. So I installed the attached patch
    Paul> to implement and document the workaround, and am optimistically
    Paul> closing the bug report.

Looks good to me. I was trying to avoid that, since I thought there
was a strong desire to keep the file read-only, otherwise why bother
with the fchmod in the first place?

Robert