From cbe6f88b5ee7fa3394e916a8a7fe893066923b73 Mon Sep 17 00:00:00 2001 From: Samuel Thibault Date: Mon, 17 Dec 2012 00:05:04 +0100 Subject: Make io_select return errors instead of returning 0 and make clients have to actually read the error. This makes implementing "poll" much easier. Based on Svante Signell's patch. * pflocal/io.c (S_io_select): Return error returned by pipe_wait_readable or pipe_wait_writable. * trans/fifo.c (trivfs_S_io_select): Return error returned by pipe_wait_readable or pipe_wait_writable. Return EBADF on bogus access mode. * trans/new-fifo.c (trivfs_S_io_select): Likewise. --- pflocal/io.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) (limited to 'pflocal') diff --git a/pflocal/io.c b/pflocal/io.c index f67052f3..2301611e 100644 --- a/pflocal/io.c +++ b/pflocal/io.c @@ -231,15 +231,24 @@ S_io_select (struct sock_user *user, if (valid & SELECT_READ) { pipe_acquire_reader (read_pipe); - if (pipe_wait_readable (read_pipe, 1, 1) != EWOULDBLOCK) - ready |= SELECT_READ; /* Data immediately readable (or error). */ + err = pipe_wait_readable (read_pipe, 1, 1); + if (err == EWOULDBLOCK) + err = 0; /* Not readable, actually not an error. */ + else + ready |= SELECT_READ; /* Data immediately readable (or error). */ pthread_mutex_unlock (&read_pipe->lock); + if (err) + /* Prevent write test from overwriting err. */ + valid &= ~SELECT_WRITE; } if (valid & SELECT_WRITE) { pipe_acquire_writer (write_pipe); - if (pipe_wait_writable (write_pipe, 1) != EWOULDBLOCK) - ready |= SELECT_WRITE; /* Data immediately writable (or error). */ + err = pipe_wait_writable (write_pipe, 1); + if (err == EWOULDBLOCK) + err = 0; /* Not writable, actually not an error. */ + else + ready |= SELECT_WRITE; /* Data immediately writable (or error). */ pthread_mutex_unlock (&write_pipe->lock); } -- cgit v1.2.3