Why SIGLOST on read()?

[Samuel Thibault]

Hello,

screen reads /proc/pid/stat, which happened to be bogus on my box.  The
problem I have is that instead of just getting -1 (EIO) or something
similar, screen got the SIGLOST signal.  Indeed, _hurd_fd_error_signal
does so when the server disappears.

This seems quite problematic as POSIX doesn't say that read() might
raise signals (while write may indeed raise SIGPIPE): a posixly correct
application may then unexpectedly terminate due to a non-POSIX signal by
just read()ing some opened file from an odd translator.

Samuel