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clone: Allow specifying termination signal #348

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clone: Allow specifying termination signal #348

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57 changes: 55 additions & 2 deletions src/sched.rs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
use std::mem;
use std::{mem, ops};
use std::os::unix::io::RawFd;
use libc::{self, c_int, c_void, c_ulong, pid_t};
use {Errno, Result};
Expand Down Expand Up @@ -35,6 +35,39 @@ bitflags!{
}
}

#[derive(Clone, Copy, Debug)]
pub struct CloneFlagsArg {
flags: CloneFlags,
signal: Option<c_int>,
}

impl CloneFlagsArg {
fn bits(self) -> c_int {
self.flags.bits() | self.signal.unwrap_or(0)
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To ensure we do not overwrite the other bits, it may make sense to mask self.signal before or'ing.

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Good point. It may not be necessary if we use an enum for signals though.... will toy with it over the next few days.

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Yes it does. Because only the low 8 signals are allowed if I understand the manpage correctly.

}
}

impl ops::BitOr<c_int> for CloneFlags {
type Output = CloneFlagsArg;
fn bitor(self, rhs: c_int) -> CloneFlagsArg {
CloneFlagsArg {
flags: self,
signal: Some(rhs),
}
}
}

impl From<CloneFlags> for CloneFlagsArg {
fn from(flags: CloneFlags) -> CloneFlagsArg {
CloneFlagsArg {
flags: flags,
signal: None,
}
}
}



// Support a maximum CPU set of 1024 nodes
#[cfg(all(target_arch = "x86_64", target_os = "linux"))]
mod cpuset_attribs {
Expand Down Expand Up @@ -197,12 +230,32 @@ pub fn sched_setaffinity(pid: isize, cpuset: &CpuSet) -> Result<()> {
Errno::result(res).map(drop)
}

pub fn clone(mut cb: CloneCb, stack: &mut [u8], flags: CloneFlags) -> Result<pid_t> {
/// The clone(2) system call.
///
/// # Examples
///
/// ```no_run
/// use std::thread;
/// use std::time::Duration;
///
/// use nix::sched::clone;
/// use nix::sched::CLONE_NEWUTS;
/// use nix::sys::signal::SIGCHLD;
///
/// let mut stack = Box::new([0u8; 1024 * 1024]);
/// let pid = clone(Box::new(|| {
/// thread::sleep(Duration::from_secs(5));
/// 0
/// }), &mut stack[..], CLONE_NEWUTS | SIGCHLD).unwrap();
/// ```
pub fn clone<F: Into<CloneFlagsArg>>(mut cb: CloneCb, stack: &mut [u8], flags: F) -> Result<pid_t> {
extern "C" fn callback(data: *mut CloneCb) -> c_int {
let cb: &mut CloneCb = unsafe { &mut *data };
(*cb)() as c_int
}

let flags: CloneFlagsArg = flags.into();

let res = unsafe {
let ptr = stack.as_mut_ptr().offset(stack.len() as isize);
ffi::clone(mem::transmute(callback), ptr as *mut c_void, flags.bits(), &mut cb)
Expand Down