bug#18851: 24.4; emacs cannot be started if the current directory has been removed

[Andreas Schwab <schwab@suse.de>]

Eli Zaretskii <eliz@gnu.org> writes:

>> > > Note that the current directory can also be removed after Emacs
>> > > is started, so I expect that Emacs already supports cases like
>> > > that.
>> > 
>> > No, it does not.  Either the OS leaves the directory in existence
>> > until Emacs exits, or the OS prevents you from removing it.
>> 
>> Linux does neither.
>
> AFAIK, GNU/Linux does the former.  The directory is not physically
> removed until the last process that has an open file descriptor for it
> closes that descriptor.  Any attempts to reference that directory for
> obtaining a new descriptor will get ENOENT, i.e. the OS pretends that
> the directory doesn't exist.  But existing descriptors are valid, and
> can be used as usual.

"As usual" is an exaggeration.  Basically the only valid operations on
it are fstat and fchdir.  Any attempt at adding an entry to it (via
openat) will be rejected.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
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