1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132

use std::mem;
use std::os::unix::io::RawFd;
use std::option::Option;
use libc::{self, c_int, c_void};
use {Error, Result};
use errno::Errno;
use ::unistd::Pid;

// For some functions taking with a parameter of type CloneFlags,
// only a subset of these flags have an effect.
libc_bitflags!{
    pub struct CloneFlags: c_int {
        CLONE_VM;
        CLONE_FS;
        CLONE_FILES;
        CLONE_SIGHAND;
        CLONE_PTRACE;
        CLONE_VFORK;
        CLONE_PARENT;
        CLONE_THREAD;
        CLONE_NEWNS;
        CLONE_SYSVSEM;
        CLONE_SETTLS;
        CLONE_PARENT_SETTID;
        CLONE_CHILD_CLEARTID;
        CLONE_DETACHED;
        CLONE_UNTRACED;
        CLONE_CHILD_SETTID;
        CLONE_NEWCGROUP;
        CLONE_NEWUTS;
        CLONE_NEWIPC;
        CLONE_NEWUSER;
        CLONE_NEWPID;
        CLONE_NEWNET;
        CLONE_IO;
    }
}

pub type CloneCb<'a> = Box<FnMut() -> isize + 'a>;

#[repr(C)]
#[derive(Clone, Copy)]
#[allow(missing_debug_implementations)]
pub struct CpuSet {
    cpu_set: libc::cpu_set_t,
}

impl CpuSet {
    pub fn new() -> CpuSet {
        CpuSet { cpu_set: unsafe { mem::zeroed() } }
    }

    pub fn is_set(&self, field: usize) -> Result<bool> {
        if field >= 8 * mem::size_of::<libc::cpu_set_t>() {
            Err(Error::Sys(Errno::EINVAL))
        } else {
            Ok(unsafe { libc::CPU_ISSET(field, &self.cpu_set) })
        }
    }

    pub fn set(&mut self, field: usize) -> Result<()> {
        if field >= 8 * mem::size_of::<libc::cpu_set_t>() {
            Err(Error::Sys(Errno::EINVAL))
        } else {
            Ok(unsafe { libc::CPU_SET(field, &mut self.cpu_set) })
        }
    }

    pub fn unset(&mut self, field: usize) -> Result<()> {
        if field >= 8 * mem::size_of::<libc::cpu_set_t>() {
            Err(Error::Sys(Errno::EINVAL))
        } else {
            Ok(unsafe { libc::CPU_CLR(field, &mut self.cpu_set) })
        }
    }
}

pub fn sched_setaffinity(pid: Pid, cpuset: &CpuSet) -> Result<()> {
    let res = unsafe {
        libc::sched_setaffinity(pid.into(),
                                mem::size_of::<CpuSet>() as libc::size_t,
                                &cpuset.cpu_set)
    };

    Errno::result(res).map(drop)
}

/// Explicitly yield the processor to other threads.
///
/// [Further reading](http://pubs.opengroup.org/onlinepubs/9699919799/functions/sched_yield.html)
pub fn sched_yield() -> Result<()> {
    let res = unsafe {
        libc::sched_yield()
    };

    Errno::result(res).map(drop)
}

pub fn clone(mut cb: CloneCb,
             stack: &mut [u8],
             flags: CloneFlags,
             signal: Option<c_int>)
             -> Result<Pid> {
    extern "C" fn callback(data: *mut CloneCb) -> c_int {
        let cb: &mut CloneCb = unsafe { &mut *data };
        (*cb)() as c_int
    }

    let res = unsafe {
        let combined = flags.bits() | signal.unwrap_or(0);
        let ptr = stack.as_mut_ptr().offset(stack.len() as isize);
        let ptr_aligned = ptr.offset((ptr as usize % 16) as isize * -1);
        libc::clone(mem::transmute(callback as extern "C" fn(*mut Box<::std::ops::FnMut() -> isize>) -> i32),
                   ptr_aligned as *mut c_void,
                   combined,
                   &mut cb as *mut _ as *mut c_void)
    };

    Errno::result(res).map(Pid::from_raw)
}

pub fn unshare(flags: CloneFlags) -> Result<()> {
    let res = unsafe { libc::unshare(flags.bits()) };

    Errno::result(res).map(drop)
}

pub fn setns(fd: RawFd, nstype: CloneFlags) -> Result<()> {
    let res = unsafe { libc::setns(fd, nstype.bits()) };

    Errno::result(res).map(drop)
}