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std: Remove old_io/old_path/rand modules

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This commit entirely removes the old I/O, path, and rand modules. All
functionality has been deprecated and unstable for quite some time now!
This commit is contained in:
Alex Crichton 2015-04-09 17:42:22 -07:00
parent dabf0c6371
commit bf4e77d4b5
57 changed files with 60 additions and 22827 deletions
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627
src/libstd/sys/unix/process.rs
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@ -1,627 +0,0 @@
// Copyright 2014-2015 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 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![allow(deprecated)] // this module itself is essentially deprecated
use prelude::v1::*;
use self::Req::*;
use collections::HashMap;
use ffi::CString;
use hash::Hash;
use old_io::process::{ProcessExit, ExitStatus, ExitSignal};
use old_io::{IoResult, EndOfFile};
use libc::{self, pid_t, c_void, c_int};
use io;
use mem;
use sys::os;
use old_path::BytesContainer;
use ptr;
use sync::mpsc::{channel, Sender, Receiver};
use sys::fs::FileDesc;
use sys::{self, retry, c, wouldblock, set_nonblocking, ms_to_timeval};
use sys_common::helper_thread::Helper;
use sys_common::{AsInner, mkerr_libc, timeout};
pub use sys_common::ProcessConfig;
helper_init! { static HELPER: Helper<Req> }
/// The unique id of the process (this should never be negative).
pub struct Process {
pub pid: pid_t
}
enum Req {
NewChild(libc::pid_t, Sender<ProcessExit>, u64),
}
const CLOEXEC_MSG_FOOTER: &'static [u8] = b"NOEX";
impl Process {
pub fn id(&self) -> pid_t {
self.pid
}
pub unsafe fn kill(&self, signal: isize) -> IoResult<()> {
Process::killpid(self.pid, signal)
}
pub unsafe fn killpid(pid: pid_t, signal: isize) -> IoResult<()> {
let r = libc::funcs::posix88::signal::kill(pid, signal as c_int);
mkerr_libc(r)
}
pub fn spawn<K, V, C, P>(cfg: &C, in_fd: Option<P>,
out_fd: Option<P>, err_fd: Option<P>)
-> IoResult<Process>
where C: ProcessConfig<K, V>, P: AsInner<FileDesc>,
K: BytesContainer + Eq + Hash, V: BytesContainer
{
use libc::funcs::posix88::unistd::{fork, dup2, close, chdir, execvp};
mod rustrt {
extern {
pub fn rust_unset_sigprocmask();
}
}
unsafe fn set_cloexec(fd: c_int) {
let ret = c::ioctl(fd, c::FIOCLEX);
assert_eq!(ret, 0);
}
#[cfg(all(target_os = "android", target_arch = "aarch64"))]
unsafe fn getdtablesize() -> c_int {
libc::sysconf(libc::consts::os::sysconf::_SC_OPEN_MAX) as c_int
}
#[cfg(not(all(target_os = "android", target_arch = "aarch64")))]
unsafe fn getdtablesize() -> c_int {
libc::funcs::bsd44::getdtablesize()
}
let dirp = cfg.cwd().map(|c| c.as_ptr()).unwrap_or(ptr::null());
// temporary until unboxed closures land
let cfg = unsafe {
mem::transmute::<&ProcessConfig<K,V>,&'static ProcessConfig<K,V>>(cfg)
};
with_envp(cfg.env(), move|envp: *const c_void| {
with_argv(cfg.program(), cfg.args(), move|argv: *const *const libc::c_char| unsafe {
let (input, mut output) = try!(sys::os::pipe());
// We may use this in the child, so perform allocations before the
// fork
let devnull = b"/dev/null\0";
set_cloexec(output.fd());
let pid = fork();
if pid < 0 {
return Err(super::last_error())
} else if pid > 0 {
#[inline]
fn combine(arr: &[u8]) -> i32 {
let a = arr[0] as u32;
let b = arr[1] as u32;
let c = arr[2] as u32;
let d = arr[3] as u32;
((a << 24) | (b << 16) | (c << 8) | (d << 0)) as i32
}
let p = Process{ pid: pid };
drop(output);
let mut bytes = [0; 8];
return match input.read(&mut bytes) {
Ok(8) => {
assert!(combine(CLOEXEC_MSG_FOOTER) == combine(&bytes[4.. 8]),
"Validation on the CLOEXEC pipe failed: {:?}", bytes);
let errno = combine(&bytes[0.. 4]);
assert!(p.wait(0).is_ok(), "wait(0) should either return Ok or panic");
Err(super::decode_error(errno))
}
Err(ref e) if e.kind == EndOfFile => Ok(p),
Err(e) => {
assert!(p.wait(0).is_ok(), "wait(0) should either return Ok or panic");
panic!("the CLOEXEC pipe failed: {:?}", e)
},
Ok(..) => { // pipe I/O up to PIPE_BUF bytes should be atomic
assert!(p.wait(0).is_ok(), "wait(0) should either return Ok or panic");
panic!("short read on the CLOEXEC pipe")
}
};
}
// And at this point we've reached a special time in the life of the
// child. The child must now be considered hamstrung and unable to
// do anything other than syscalls really. Consider the following
// scenario:
//
// 1. Thread A of process 1 grabs the malloc() mutex
// 2. Thread B of process 1 forks(), creating thread C
// 3. Thread C of process 2 then attempts to malloc()
// 4. The memory of process 2 is the same as the memory of
// process 1, so the mutex is locked.
//
// This situation looks a lot like deadlock, right? It turns out
// that this is what pthread_atfork() takes care of, which is
// presumably implemented across platforms. The first thing that
// threads to *before* forking is to do things like grab the malloc
// mutex, and then after the fork they unlock it.
//
// Despite this information, libnative's spawn has been witnessed to
// deadlock on both OSX and FreeBSD. I'm not entirely sure why, but
// all collected backtraces point at malloc/free traffic in the
// child spawned process.
//
// For this reason, the block of code below should contain 0
// invocations of either malloc of free (or their related friends).
//
// As an example of not having malloc/free traffic, we don't close
// this file descriptor by dropping the FileDesc (which contains an
// allocation). Instead we just close it manually. This will never
// have the drop glue anyway because this code never returns (the
// child will either exec() or invoke libc::exit)
let _ = libc::close(input.fd());
fn fail(output: &mut FileDesc) -> ! {
let errno = sys::os::errno() as u32;
let bytes = [
(errno >> 24) as u8,
(errno >> 16) as u8,
(errno >> 8) as u8,
(errno >> 0) as u8,
CLOEXEC_MSG_FOOTER[0], CLOEXEC_MSG_FOOTER[1],
CLOEXEC_MSG_FOOTER[2], CLOEXEC_MSG_FOOTER[3]
];
// pipe I/O up to PIPE_BUF bytes should be atomic
assert!(output.write(&bytes).is_ok());
unsafe { libc::_exit(1) }
}
rustrt::rust_unset_sigprocmask();
// If a stdio file descriptor is set to be ignored (via a -1 file
// descriptor), then we don't actually close it, but rather open
// up /dev/null into that file descriptor. Otherwise, the first file
// descriptor opened up in the child would be numbered as one of the
// stdio file descriptors, which is likely to wreak havoc.
let setup = |src: Option<P>, dst: c_int| {
let src = match src {
None => {
let flags = if dst == libc::STDIN_FILENO {
libc::O_RDONLY
} else {
libc::O_RDWR
};
libc::open(devnull.as_ptr() as *const _, flags, 0)
}
Some(obj) => {
let fd = obj.as_inner().fd();
// Leak the memory and the file descriptor. We're in the
// child now an all our resources are going to be
// cleaned up very soon
mem::forget(obj);
fd
}
};
src != -1 && retry(|| dup2(src, dst)) != -1
};
if !setup(in_fd, libc::STDIN_FILENO) { fail(&mut output) }
if !setup(out_fd, libc::STDOUT_FILENO) { fail(&mut output) }
if !setup(err_fd, libc::STDERR_FILENO) { fail(&mut output) }
// close all other fds
for fd in (3..getdtablesize()).rev() {
if fd != output.fd() {
let _ = close(fd as c_int);
}
}
match cfg.gid() {
Some(u) => {
if libc::setgid(u as libc::gid_t) != 0 {
fail(&mut output);
}
}
None => {}
}
match cfg.uid() {
Some(u) => {
// When dropping privileges from root, the `setgroups` call
// will remove any extraneous groups. If we don't call this,
// then even though our uid has dropped, we may still have
// groups that enable us to do super-user things. This will
// fail if we aren't root, so don't bother checking the
// return value, this is just done as an optimistic
// privilege dropping function.
extern {
fn setgroups(ngroups: libc::c_int,
ptr: *const libc::c_void) -> libc::c_int;
}
let _ = setgroups(0, ptr::null());
if libc::setuid(u as libc::uid_t) != 0 {
fail(&mut output);
}
}
None => {}
}
if cfg.detach() {
// Don't check the error of setsid because it fails if we're the
// process leader already. We just forked so it shouldn't return
// error, but ignore it anyway.
let _ = libc::setsid();
}
if !dirp.is_null() && chdir(dirp) == -1 {
fail(&mut output);
}
if !envp.is_null() {
*sys::os::environ() = envp as *const _;
}
let _ = execvp(*argv, argv as *mut _);
fail(&mut output);
})
})
}
pub fn wait(&self, deadline: u64) -> IoResult<ProcessExit> {
use cmp;
use sync::mpsc::TryRecvError;
static mut WRITE_FD: libc::c_int = 0;
let mut status = 0 as c_int;
if deadline == 0 {
return match retry(|| unsafe { c::waitpid(self.pid, &mut status, 0) }) {
-1 => panic!("unknown waitpid error: {:?}", super::last_error()),
_ => Ok(translate_status(status)),
}
}
// On unix, wait() and its friends have no timeout parameters, so there is
// no way to time out a thread in wait(). From some googling and some
// thinking, it appears that there are a few ways to handle timeouts in
// wait(), but the only real reasonable one for a multi-threaded program is
// to listen for SIGCHLD.
//
// With this in mind, the waiting mechanism with a timeout barely uses
// waitpid() at all. There are a few times that waitpid() is invoked with
// WNOHANG, but otherwise all the necessary blocking is done by waiting for
// a SIGCHLD to arrive (and that blocking has a timeout). Note, however,
// that waitpid() is still used to actually reap the child.
//
// Signal handling is super tricky in general, and this is no exception. Due
// to the async nature of SIGCHLD, we use the self-pipe trick to transmit
// data out of the signal handler to the rest of the application. The first
// idea would be to have each thread waiting with a timeout to read this
// output file descriptor, but a write() is akin to a signal(), not a
// broadcast(), so it would only wake up one thread, and possibly the wrong
// thread. Hence a helper thread is used.
//
// The helper thread here is responsible for farming requests for a
// waitpid() with a timeout, and then processing all of the wait requests.
// By guaranteeing that only this helper thread is reading half of the
// self-pipe, we're sure that we'll never lose a SIGCHLD. This helper thread
// is also responsible for select() to wait for incoming messages or
// incoming SIGCHLD messages, along with passing an appropriate timeout to
// select() to wake things up as necessary.
//
// The ordering of the following statements is also very purposeful. First,
// we must be guaranteed that the helper thread is booted and available to
// receive SIGCHLD signals, and then we must also ensure that we do a
// nonblocking waitpid() at least once before we go ask the sigchld helper.
// This prevents the race where the child exits, we boot the helper, and
// then we ask for the child's exit status (never seeing a sigchld).
//
// The actual communication between the helper thread and this thread is
// quite simple, just a channel moving data around.
HELPER.boot(register_sigchld, waitpid_helper);
match self.try_wait() {
Some(ret) => return Ok(ret),
None => {}
}
let (tx, rx) = channel();
HELPER.send(NewChild(self.pid, tx, deadline));
return match rx.recv() {
Ok(e) => Ok(e),
Err(..) => Err(timeout("wait timed out")),
};
// Register a new SIGCHLD handler, returning the reading half of the
// self-pipe plus the old handler registered (return value of sigaction).
//
// Be sure to set up the self-pipe first because as soon as we register a
// handler we're going to start receiving signals.
fn register_sigchld() -> (libc::c_int, c::sigaction) {
unsafe {
let mut pipes = [0; 2];
assert_eq!(libc::pipe(pipes.as_mut_ptr()), 0);
set_nonblocking(pipes[0], true);
set_nonblocking(pipes[1], true);
WRITE_FD = pipes[1];
let mut old: c::sigaction = mem::zeroed();
let mut new: c::sigaction = mem::zeroed();
new.sa_handler = sigchld_handler;
new.sa_flags = c::SA_NOCLDSTOP;
assert_eq!(c::sigaction(c::SIGCHLD, &new, &mut old), 0);
(pipes[0], old)
}
}
// Helper thread for processing SIGCHLD messages
fn waitpid_helper(input: libc::c_int,
messages: Receiver<Req>,
(read_fd, old): (libc::c_int, c::sigaction)) {
set_nonblocking(input, true);
let mut set: c::fd_set = unsafe { mem::zeroed() };
let mut tv: libc::timeval;
let mut active = Vec::<(libc::pid_t, Sender<ProcessExit>, u64)>::new();
let max = cmp::max(input, read_fd) + 1;
'outer: loop {
// Figure out the timeout of our syscall-to-happen. If we're waiting
// for some processes, then they'll have a timeout, otherwise we
// wait indefinitely for a message to arrive.
//
// FIXME: sure would be nice to not have to scan the entire array
let min = active.iter().map(|a| a.2).enumerate().min_by(|p| {
p.1
});
let (p, idx) = match min {
Some((idx, deadline)) => {
let now = sys::timer::now();
let ms = if now < deadline {deadline - now} else {0};
tv = ms_to_timeval(ms);
(&mut tv as *mut _, idx)
}
None => (ptr::null_mut(), -1),
};
// Wait for something to happen
c::fd_set(&mut set, input);
c::fd_set(&mut set, read_fd);
match unsafe { c::select(max, &mut set, ptr::null_mut(),
ptr::null_mut(), p) } {
// interrupted, retry
-1 if os::errno() == libc::EINTR as i32 => continue,
// We read something, break out and process
1 | 2 => {}
// Timeout, the pending request is removed
0 => {
drop(active.remove(idx));
continue
}
n => panic!("error in select {:?} ({:?})", os::errno(), n),
}
// Process any pending messages
if drain(input) {
loop {
match messages.try_recv() {
Ok(NewChild(pid, tx, deadline)) => {
active.push((pid, tx, deadline));
}
// Once we've been disconnected it means the main
// thread is exiting (at_exit has run). We could
// still have active waiter for other threads, so
// we're just going to drop them all on the floor.
// This means that they won't receive a "you're
// done" message in which case they'll be considered
// as timed out, but more generally errors will
// start propagating.
Err(TryRecvError::Disconnected) => {
break 'outer;
}
Err(TryRecvError::Empty) => break,
}
}
}
// If a child exited (somehow received SIGCHLD), then poll all
// children to see if any of them exited.
//
// We also attempt to be responsible netizens when dealing with
// SIGCHLD by invoking any previous SIGCHLD handler instead of just
// ignoring any previous SIGCHLD handler. Note that we don't provide
// a 1:1 mapping of our handler invocations to the previous handler
// invocations because we drain the `read_fd` entirely. This is
// probably OK because the kernel is already allowed to coalesce
// simultaneous signals, we're just doing some extra coalescing.
//
// Another point of note is that this likely runs the signal handler
// on a different thread than the one that received the signal. I
// *think* this is ok at this time.
//
// The main reason for doing this is to allow stdtest to run native
// tests as well. Both libgreen and libnative are running around
// with process timeouts, but libgreen should get there first
// (currently libuv doesn't handle old signal handlers).
if drain(read_fd) {
let i: usize = unsafe { mem::transmute(old.sa_handler) };
if i != 0 {
assert!(old.sa_flags & c::SA_SIGINFO == 0);
(old.sa_handler)(c::SIGCHLD);
}
// FIXME: sure would be nice to not have to scan the entire
// array...
active.retain(|&(pid, ref tx, _)| {
let pr = Process { pid: pid };
match pr.try_wait() {
Some(msg) => { tx.send(msg).unwrap(); false }
None => true,
}
});
}
}
// Once this helper thread is done, we re-register the old sigchld
// handler and close our intermediate file descriptors.
unsafe {
assert_eq!(c::sigaction(c::SIGCHLD, &old, ptr::null_mut()), 0);
let _ = libc::close(read_fd);
let _ = libc::close(WRITE_FD);
WRITE_FD = -1;
}
}
// Drain all pending data from the file descriptor, returning if any data
// could be drained. This requires that the file descriptor is in
// nonblocking mode.
fn drain(fd: libc::c_int) -> bool {
let mut ret = false;
loop {
let mut buf = [0u8; 1];
match unsafe {
libc::read(fd, buf.as_mut_ptr() as *mut libc::c_void,
buf.len() as libc::size_t)
} {
n if n > 0 => { ret = true; }
0 => return true,
-1 if wouldblock() => return ret,
n => panic!("bad read {} ({})",
io::Error::last_os_error(), n),
}
}
}
// Signal handler for SIGCHLD signals, must be async-signal-safe!
//
// This function will write to the writing half of the "self pipe" to wake
// up the helper thread if it's waiting. Note that this write must be
// nonblocking because if it blocks and the reader is the thread we
// interrupted, then we'll deadlock.
//
// When writing, if the write returns EWOULDBLOCK then we choose to ignore
// it. At that point we're guaranteed that there's something in the pipe
// which will wake up the other end at some point, so we just allow this
// signal to be coalesced with the pending signals on the pipe.
extern fn sigchld_handler(_signum: libc::c_int) {
let msg = 1;
match unsafe {
libc::write(WRITE_FD, &msg as *const _ as *const libc::c_void, 1)
} {
1 => {}
-1 if wouldblock() => {} // see above comments
n => panic!("bad error on write fd: {:?} {:?}", n, os::errno()),
}
}
}
pub fn try_wait(&self) -> Option<ProcessExit> {
let mut status = 0 as c_int;
match retry(|| unsafe {
c::waitpid(self.pid, &mut status, c::WNOHANG)
}) {
n if n == self.pid => Some(translate_status(status)),
0 => None,
n => panic!("unknown waitpid error `{:?}`: {:?}", n,
super::last_error()),
}
}
}
fn with_argv<T,F>(prog: &CString, args: &[CString],
cb: F)
-> T
where F : FnOnce(*const *const libc::c_char) -> T
{
let mut ptrs: Vec<*const libc::c_char> = Vec::with_capacity(args.len()+1);
// Convert the CStrings into an array of pointers. Note: the
// lifetime of the various CStrings involved is guaranteed to be
// larger than the lifetime of our invocation of cb, but this is
// technically unsafe as the callback could leak these pointers
// out of our scope.
ptrs.push(prog.as_ptr());
ptrs.extend(args.iter().map(|tmp| tmp.as_ptr()));
// Add a terminating null pointer (required by libc).
ptrs.push(ptr::null());
cb(ptrs.as_ptr())
}
fn with_envp<K,V,T,F>(env: Option<&HashMap<K, V>>,
cb: F)
-> T
where F : FnOnce(*const c_void) -> T,
K : BytesContainer + Eq + Hash,
V : BytesContainer
{
// On posixy systems we can pass a char** for envp, which is a
// null-terminated array of "k=v\0" strings. Since we must create
// these strings locally, yet expose a raw pointer to them, we
// create a temporary vector to own the CStrings that outlives the
// call to cb.
match env {
Some(env) => {
let mut tmps = Vec::with_capacity(env.len());
for pair in env {
let mut kv = Vec::new();
kv.push_all(pair.0.container_as_bytes());
kv.push('=' as u8);
kv.push_all(pair.1.container_as_bytes());
kv.push(0); // terminating null
tmps.push(kv);
}
// As with `with_argv`, this is unsafe, since cb could leak the pointers.
let mut ptrs: Vec<*const libc::c_char> =
tmps.iter()
.map(|tmp| tmp.as_ptr() as *const libc::c_char)
.collect();
ptrs.push(ptr::null());
cb(ptrs.as_ptr() as *const c_void)
}
_ => cb(ptr::null())
}
}
fn translate_status(status: c_int) -> ProcessExit {
#![allow(non_snake_case)]
#[cfg(any(target_os = "linux", target_os = "android"))]
mod imp {
pub fn WIFEXITED(status: i32) -> bool { (status & 0xff) == 0 }
pub fn WEXITSTATUS(status: i32) -> i32 { (status >> 8) & 0xff }
pub fn WTERMSIG(status: i32) -> i32 { status & 0x7f }
}
#[cfg(any(target_os = "macos",
target_os = "ios",
target_os = "freebsd",
target_os = "dragonfly",
target_os = "bitrig",
target_os = "openbsd"))]
mod imp {
pub fn WIFEXITED(status: i32) -> bool { (status & 0x7f) == 0 }
pub fn WEXITSTATUS(status: i32) -> i32 { status >> 8 }
pub fn WTERMSIG(status: i32) -> i32 { status & 0o177 }
}
if imp::WIFEXITED(status) {
ExitStatus(imp::WEXITSTATUS(status) as isize)
} else {
ExitSignal(imp::WTERMSIG(status) as isize)
}
}