From 8c01ce3d2552529af7597a60329d0552d2b0f325 Mon Sep 17 00:00:00 2001 From: Alex Crichton Date: Mon, 3 Apr 2017 11:41:45 -0700 Subject: [PATCH] std: Use `poll` instead of `select` This gives us the benefit of supporting file descriptors over the limit that select supports, which... Closes #40894 --- src/libstd/sys/unix/pipe.rs | 22 +++++++++------------- 1 file changed, 9 insertions(+), 13 deletions(-) diff --git a/src/libstd/sys/unix/pipe.rs b/src/libstd/sys/unix/pipe.rs index 51e00fc1ab9..706256ff10e 100644 --- a/src/libstd/sys/unix/pipe.rs +++ b/src/libstd/sys/unix/pipe.rs @@ -8,11 +8,9 @@ // option. This file may not be copied, modified, or distributed // except according to those terms. -use cmp; use io; use libc::{self, c_int}; use mem; -use ptr; use sys::{cvt, cvt_r}; use sys::fd::FileDesc; @@ -80,16 +78,14 @@ pub fn read2(p1: AnonPipe, p1.set_nonblocking(true)?; p2.set_nonblocking(true)?; - let max = cmp::max(p1.raw(), p2.raw()); + let mut fds: [libc::pollfd; 2] = unsafe { mem::zeroed() }; + fds[0].fd = p1.raw(); + fds[0].events = libc::POLLIN; + fds[1].fd = p2.raw(); + fds[1].events = libc::POLLIN; loop { - // wait for either pipe to become readable using `select` - cvt_r(|| unsafe { - let mut read: libc::fd_set = mem::zeroed(); - libc::FD_SET(p1.raw(), &mut read); - libc::FD_SET(p2.raw(), &mut read); - libc::select(max + 1, &mut read, ptr::null_mut(), ptr::null_mut(), - ptr::null_mut()) - })?; + // wait for either pipe to become readable using `poll` + cvt_r(|| unsafe { libc::poll(fds.as_mut_ptr(), 2, -1) })?; // Read as much as we can from each pipe, ignoring EWOULDBLOCK or // EAGAIN. If we hit EOF, then this will happen because the underlying @@ -109,11 +105,11 @@ pub fn read2(p1: AnonPipe, } } }; - if read(&p1, v1)? { + if fds[0].revents != 0 && read(&p1, v1)? { p2.set_nonblocking(false)?; return p2.read_to_end(v2).map(|_| ()); } - if read(&p2, v2)? { + if fds[1].revents != 0 && read(&p2, v2)? { p1.set_nonblocking(false)?; return p1.read_to_end(v1).map(|_| ()); }