From 28ba3a7bc3e1561528e3d441ad653ac849ee07ea Mon Sep 17 00:00:00 2001 From: Alex Crichton Date: Thu, 10 Apr 2014 21:44:02 -0700 Subject: [PATCH] native: Remove timerfd implementation on linux Rust advertises itself as being compatible with linux 2.6.18, but the timerfd set of syscalls weren't added until linux 2.6.25. There is no real need for a specialized timer implementation beyond being a "little more accurate", but the select() implementation will suffice for now. If it is later deemed that an accurate timerfd implementation is needed, it can be added then through some method which will allow the standard distribution to continue to be compatible with 2.6.18 Closes #13447 --- src/libnative/io/mod.rs | 5 +- src/libnative/io/timer_timerfd.rs | 327 ------------------ .../io/{timer_other.rs => timer_unix.rs} | 7 +- 3 files changed, 6 insertions(+), 333 deletions(-) delete mode 100644 src/libnative/io/timer_timerfd.rs rename src/libnative/io/{timer_other.rs => timer_unix.rs} (98%) diff --git a/src/libnative/io/mod.rs b/src/libnative/io/mod.rs index cc432555abb92..78d17bc8d747f 100644 --- a/src/libnative/io/mod.rs +++ b/src/libnative/io/mod.rs @@ -55,11 +55,8 @@ pub mod file; #[cfg(target_os = "macos")] #[cfg(target_os = "freebsd")] #[cfg(target_os = "android")] -#[path = "timer_other.rs"] -pub mod timer; - #[cfg(target_os = "linux")] -#[path = "timer_timerfd.rs"] +#[path = "timer_unix.rs"] pub mod timer; #[cfg(target_os = "win32")] diff --git a/src/libnative/io/timer_timerfd.rs b/src/libnative/io/timer_timerfd.rs deleted file mode 100644 index 3fd61dc1da5d0..0000000000000 --- a/src/libnative/io/timer_timerfd.rs +++ /dev/null @@ -1,327 +0,0 @@ -// Copyright 2013-2014 The Rust Project Developers. See the COPYRIGHT -// file at the top-level directory of this distribution and at -// http://rust-lang.org/COPYRIGHT. -// -// Licensed under the Apache License, Version 2.0 or the MIT license -// , at your -// option. This file may not be copied, modified, or distributed -// except according to those terms. - -//! Timers based on timerfd_create(2) -//! -//! On OSes which support timerfd_create, we can use these much more accurate -//! timers over select() + a timeout (see timer_other.rs). This strategy still -//! employs a worker thread which does the waiting on the timer fds (to send -//! messages away). -//! -//! The worker thread in this implementation uses epoll(7) to block. It -//! maintains a working set of *all* native timers in the process, along with a -//! pipe file descriptor used to communicate that there is data available on the -//! incoming channel to the worker thread. Timers send requests to update their -//! timerfd settings to the worker thread (see the comment above 'oneshot' for -//! why). -//! -//! As with timer_other, timers just using sleep() do not use the timerfd at -//! all. They remove the timerfd from the worker thread and then invoke -//! nanosleep() to block the calling thread. -//! -//! As with timer_other, all units in this file are in units of millseconds. - -use libc; -use std::ptr; -use std::os; -use std::rt::rtio; -use std::mem; - -use io::file::FileDesc; -use io::IoResult; -use io::timer_helper; - -pub struct Timer { - fd: FileDesc, - on_worker: bool, -} - -#[allow(visible_private_types)] -pub enum Req { - NewTimer(libc::c_int, Sender<()>, bool, imp::itimerspec), - RemoveTimer(libc::c_int, Sender<()>), - Shutdown, -} - -fn helper(input: libc::c_int, messages: Receiver) { - let efd = unsafe { imp::epoll_create(10) }; - let _fd1 = FileDesc::new(input, true); - let _fd2 = FileDesc::new(efd, true); - - fn add(efd: libc::c_int, fd: libc::c_int) { - let event = imp::epoll_event { - events: imp::EPOLLIN as u32, - data: fd as i64, - }; - let ret = unsafe { - imp::epoll_ctl(efd, imp::EPOLL_CTL_ADD, fd, &event) - }; - assert_eq!(ret, 0); - } - fn del(efd: libc::c_int, fd: libc::c_int) { - let event = imp::epoll_event { events: 0, data: 0 }; - let ret = unsafe { - imp::epoll_ctl(efd, imp::EPOLL_CTL_DEL, fd, &event) - }; - assert_eq!(ret, 0); - } - - add(efd, input); - let events: [imp::epoll_event, ..16] = unsafe { mem::init() }; - let mut list: Vec<(libc::c_int, Sender<()>, bool)> = vec![]; - 'outer: loop { - let n = match unsafe { - imp::epoll_wait(efd, events.as_ptr(), - events.len() as libc::c_int, -1) - } { - 0 => fail!("epoll_wait returned immediately!"), - -1 if os::errno() == libc::EINTR as int => { continue } - -1 => fail!("epoll wait failed: {}", os::last_os_error()), - n => n - }; - - let mut incoming = false; - for event in events.slice_to(n as uint).iter() { - let fd = event.data as libc::c_int; - if fd == input { - let mut buf = [0, ..1]; - // drain the input file descriptor of its input - let _ = FileDesc::new(fd, false).inner_read(buf).unwrap(); - incoming = true; - } else { - let mut bits = [0, ..8]; - // drain the timerfd of how many times its fired - // - // FIXME: should this perform a send() this number of - // times? - let _ = FileDesc::new(fd, false).inner_read(bits).unwrap(); - let (remove, i) = { - match list.as_slice().bsearch(|&(f, _, _)| f.cmp(&fd)) { - Some(i) => { - let (_, ref c, oneshot) = *list.get(i); - (c.send_opt(()).is_err() || oneshot, i) - } - None => fail!("fd not active: {}", fd), - } - }; - if remove { - drop(list.remove(i)); - del(efd, fd); - } - } - } - - while incoming { - match messages.try_recv() { - Ok(NewTimer(fd, chan, one, timeval)) => { - // acknowledge we have the new channel, we will never send - // another message to the old channel - chan.send(()); - - // If we haven't previously seen the file descriptor, then - // we need to add it to the epoll set. - match list.as_slice().bsearch(|&(f, _, _)| f.cmp(&fd)) { - Some(i) => { - drop(mem::replace(list.get_mut(i), (fd, chan, one))); - } - None => { - match list.iter().position(|&(f, _, _)| f >= fd) { - Some(i) => list.insert(i, (fd, chan, one)), - None => list.push((fd, chan, one)), - } - add(efd, fd); - } - } - - // Update the timerfd's time value now that we have control - // of the timerfd - let ret = unsafe { - imp::timerfd_settime(fd, 0, &timeval, ptr::null()) - }; - assert_eq!(ret, 0); - } - - Ok(RemoveTimer(fd, chan)) => { - match list.as_slice().bsearch(|&(f, _, _)| f.cmp(&fd)) { - Some(i) => { - drop(list.remove(i)); - del(efd, fd); - } - None => {} - } - chan.send(()); - } - - Ok(Shutdown) => { - assert!(list.len() == 0); - break 'outer; - } - - _ => break, - } - } - } -} - -impl Timer { - pub fn new() -> IoResult { - timer_helper::boot(helper); - match unsafe { imp::timerfd_create(imp::CLOCK_MONOTONIC, 0) } { - -1 => Err(super::last_error()), - n => Ok(Timer { fd: FileDesc::new(n, true), on_worker: false, }), - } - } - - pub fn sleep(ms: u64) { - let mut to_sleep = libc::timespec { - tv_sec: (ms / 1000) as libc::time_t, - tv_nsec: ((ms % 1000) * 1000000) as libc::c_long, - }; - while unsafe { libc::nanosleep(&to_sleep, &mut to_sleep) } != 0 { - if os::errno() as int != libc::EINTR as int { - fail!("failed to sleep, but not because of EINTR?"); - } - } - } - - fn remove(&mut self) { - if !self.on_worker { return } - - let (tx, rx) = channel(); - timer_helper::send(RemoveTimer(self.fd.fd(), tx)); - rx.recv(); - self.on_worker = false; - } -} - -impl rtio::RtioTimer for Timer { - fn sleep(&mut self, msecs: u64) { - self.remove(); - Timer::sleep(msecs); - } - - // Periodic and oneshot channels are updated by updating the settings on the - // corresopnding timerfd. The update is not performed on the thread calling - // oneshot or period, but rather the helper epoll thread. The reason for - // this is to avoid losing messages and avoid leaking messages across ports. - // - // By updating the timerfd on the helper thread, we're guaranteed that all - // messages for a particular setting of the timer will be received by the - // new channel/port pair rather than leaking old messages onto the new port - // or leaking new messages onto the old port. - // - // We also wait for the remote thread to actually receive the new settings - // before returning to guarantee the invariant that when oneshot() and - // period() return that the old port will never receive any more messages. - - fn oneshot(&mut self, msecs: u64) -> Receiver<()> { - let (tx, rx) = channel(); - - let new_value = imp::itimerspec { - it_interval: imp::timespec { tv_sec: 0, tv_nsec: 0 }, - it_value: imp::timespec { - tv_sec: (msecs / 1000) as libc::time_t, - tv_nsec: ((msecs % 1000) * 1000000) as libc::c_long, - } - }; - timer_helper::send(NewTimer(self.fd.fd(), tx, true, new_value)); - rx.recv(); - self.on_worker = true; - - return rx; - } - - fn period(&mut self, msecs: u64) -> Receiver<()> { - let (tx, rx) = channel(); - - let spec = imp::timespec { - tv_sec: (msecs / 1000) as libc::time_t, - tv_nsec: ((msecs % 1000) * 1000000) as libc::c_long, - }; - let new_value = imp::itimerspec { it_interval: spec, it_value: spec, }; - timer_helper::send(NewTimer(self.fd.fd(), tx, false, new_value)); - rx.recv(); - self.on_worker = true; - - return rx; - } -} - -impl Drop for Timer { - fn drop(&mut self) { - // When the timerfd file descriptor is closed, it will be automatically - // removed from the epoll set of the worker thread, but we want to make - // sure that the associated channel is also removed from the worker's - // hash map. - self.remove(); - } -} - -#[allow(dead_code)] -mod imp { - use libc; - - pub static CLOCK_MONOTONIC: libc::c_int = 1; - pub static EPOLL_CTL_ADD: libc::c_int = 1; - pub static EPOLL_CTL_DEL: libc::c_int = 2; - pub static EPOLL_CTL_MOD: libc::c_int = 3; - pub static EPOLLIN: libc::c_int = 0x001; - pub static EPOLLOUT: libc::c_int = 0x004; - pub static EPOLLPRI: libc::c_int = 0x002; - pub static EPOLLERR: libc::c_int = 0x008; - pub static EPOLLRDHUP: libc::c_int = 0x2000; - pub static EPOLLET: libc::c_int = 1 << 31; - pub static EPOLLHUP: libc::c_int = 0x010; - pub static EPOLLONESHOT: libc::c_int = 1 << 30; - - #[cfg(target_arch = "x86_64")] - #[packed] - pub struct epoll_event { - pub events: u32, - pub data: i64, - } - - #[cfg(not(target_arch = "x86_64"))] - pub struct epoll_event { - pub events: u32, - pub data: i64, - } - - pub struct timespec { - pub tv_sec: libc::time_t, - pub tv_nsec: libc::c_long, - } - - pub struct itimerspec { - pub it_interval: timespec, - pub it_value: timespec, - } - - extern { - pub fn timerfd_create(clockid: libc::c_int, - flags: libc::c_int) -> libc::c_int; - pub fn timerfd_settime(fd: libc::c_int, - flags: libc::c_int, - new_value: *itimerspec, - old_value: *itimerspec) -> libc::c_int; - pub fn timerfd_gettime(fd: libc::c_int, - curr_value: *itimerspec) -> libc::c_int; - - pub fn epoll_create(size: libc::c_int) -> libc::c_int; - pub fn epoll_ctl(epfd: libc::c_int, - op: libc::c_int, - fd: libc::c_int, - event: *epoll_event) -> libc::c_int; - pub fn epoll_wait(epfd: libc::c_int, - events: *epoll_event, - maxevents: libc::c_int, - timeout: libc::c_int) -> libc::c_int; - } -} diff --git a/src/libnative/io/timer_other.rs b/src/libnative/io/timer_unix.rs similarity index 98% rename from src/libnative/io/timer_other.rs rename to src/libnative/io/timer_unix.rs index 0bf97d58ffdff..0444604d42a0b 100644 --- a/src/libnative/io/timer_other.rs +++ b/src/libnative/io/timer_unix.rs @@ -312,17 +312,20 @@ mod imp { #[cfg(target_os = "android")] #[cfg(target_os = "freebsd")] +#[cfg(target_os = "linux")] mod imp { use libc; + use std::uint; pub static FD_SETSIZE: uint = 1024; pub struct fd_set { - fds_bits: [u64, ..(FD_SETSIZE / 64)] + fds_bits: [uint, ..(FD_SETSIZE / uint::BITS)] } pub fn fd_set(set: &mut fd_set, fd: i32) { - set.fds_bits[(fd / 64) as uint] |= (1 << (fd % 64)) as u64; + let fd = fd as uint; + set.fds_bits[fd / uint::BITS] |= 1 << (fd % uint::BITS); } extern {