summaryrefslogtreecommitdiff
path: root/src/mqueue.rs
blob: e24b6800115d21bef737df370ec600072bb3c88c (plain)
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
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
//! Posix Message Queue functions
//!
//! [Further reading and details on the C API](http://man7.org/linux/man-pages/man7/mq_overview.7.html)

use {Error, Result, from_ffi};
use errno::Errno;

use libc::{c_int, c_long, c_char, size_t, mode_t, strlen};
use std::ffi::CString;
use sys::stat::Mode;

pub use self::consts::*;

pub type MQd = c_int;

#[cfg(target_os = "linux")]
mod consts {
    use libc::c_int;

    bitflags!(
        flags MQ_OFlag: c_int {
            const O_RDONLY    = 0o00000000,
            const O_WRONLY    = 0o00000001,
            const O_RDWR      = 0o00000002,
            const O_CREAT     = 0o00000100,
            const O_EXCL      = 0o00000200,
            const O_NONBLOCK  = 0o00004000,
            const O_CLOEXEC   = 0o02000000,
        }
    );

    bitflags!(
        flags FdFlag: c_int {
            const FD_CLOEXEC = 1
        }
    );
}

mod ffi {
    use libc::{c_char, size_t, ssize_t, c_uint, c_int};
    use super::MQd;
    use super::MqAttr;

    #[allow(improper_ctypes)]
    extern "C" {
        pub fn mq_open(name: *const c_char, oflag: c_int, ...) -> MQd;

        pub fn mq_close (mqd: MQd) -> c_int;

        pub fn mq_unlink(name: *const c_char) -> c_int;

        pub fn mq_receive (mqd: MQd, msg_ptr: *const c_char, msg_len: size_t, msq_prio: *const c_uint) -> ssize_t;

        pub fn mq_send (mqd: MQd, msg_ptr: *const c_char, msg_len: size_t, msq_prio: c_uint) -> c_int;

        pub fn mq_getattr(mqd: MQd, attr: *mut MqAttr) -> c_int;

        pub fn mq_setattr(mqd: MQd, newattr: *const MqAttr, oldattr: *mut MqAttr) -> c_int;
    }
}

#[repr(C)]
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub struct MqAttr {
    pub mq_flags: c_long,
    pub mq_maxmsg: c_long,
    pub mq_msgsize: c_long,
    pub mq_curmsgs: c_long,
    pad: [c_long; 4]
}

impl MqAttr {
   pub fn new(mq_flags: c_long, mq_maxmsg: c_long, mq_msgsize: c_long, mq_curmsgs: c_long) -> MqAttr {
       MqAttr { mq_flags: mq_flags, mq_maxmsg: mq_maxmsg, mq_msgsize: mq_msgsize, mq_curmsgs: mq_curmsgs, pad: [0; 4] }
   }
}


#[inline]
pub fn mq_open(name: &CString, oflag: MQ_OFlag, mode: Mode, attr: &MqAttr) -> Result<MQd> {
    let res = unsafe { ffi::mq_open(name.as_ptr(), oflag.bits(), mode.bits() as mode_t, attr as *const MqAttr) };

    if res < 0 {
        return Err(Error::Sys(Errno::last()));
    }

    Ok(res)
}

pub fn mq_unlink(name: &CString) -> Result<()> {
    let res = unsafe { ffi::mq_unlink(name.as_ptr()) };
    from_ffi(res)
}

pub fn mq_close(mqdes: MQd) -> Result<()>  {
    let res = unsafe { ffi::mq_close(mqdes) };
    from_ffi(res)
}


pub fn mq_receive(mqdes: MQd, message: &mut [u8], msq_prio: u32) -> Result<usize> {
    let len = message.len() as size_t;
    let res = unsafe { ffi::mq_receive(mqdes, message.as_mut_ptr() as *mut c_char, len, &msq_prio) };

    if res < 0 {
        return Err(Error::Sys(Errno::last()));
    }

    Ok(res as usize)
}

pub fn mq_send(mqdes: MQd, message: &CString, msq_prio: u32) -> Result<usize> {
    let len = unsafe { strlen(message.as_ptr()) as size_t };
    let res = unsafe { ffi::mq_send(mqdes, message.as_ptr(), len, msq_prio) };

    if res < 0 {
        return Err(Error::Sys(Errno::last()));
    }

    Ok(res as usize)
}

pub fn mq_getattr(mqd: MQd) -> Result<MqAttr> {
    let mut attr = MqAttr::new(0, 0, 0, 0);
    let res = unsafe { ffi::mq_getattr(mqd, &mut attr) };
    if res < 0 {
        return Err(Error::Sys(Errno::last()));
    }
    Ok(attr)
}

/// Set the attributes of the message queue. Only O_NONBLOCK can be set, everything else will be ignored
/// Returns the old attributes
/// It is recommend to use the mq_set_nonblock() and mq_remove_nonblock() convenience functions as they are easier to use
///
/// [Further reading](http://man7.org/linux/man-pages/man3/mq_setattr.3.html)
pub fn mq_setattr(mqd: MQd, newattr: &MqAttr) -> Result<MqAttr> {
    let mut attr = MqAttr::new(0, 0, 0, 0);
    let res = unsafe { ffi::mq_setattr(mqd, newattr as *const MqAttr, &mut attr) };
    if res < 0 {
        return Err(Error::Sys(Errno::last()));
    }
    Ok(attr)
}

/// Convenience function.
/// Sets the O_NONBLOCK attribute for a given message queue descriptor
/// Returns the old attributes
pub fn mq_set_nonblock(mqd: MQd) -> Result<(MqAttr)> {
    let oldattr = try!(mq_getattr(mqd));
    let newattr = MqAttr::new(O_NONBLOCK.bits() as c_long, oldattr.mq_maxmsg, oldattr.mq_msgsize, oldattr.mq_curmsgs);
    mq_setattr(mqd, &newattr)
}

/// Convenience function.
/// Removes O_NONBLOCK attribute for a given message queue descriptor
/// Returns the old attributes
pub fn mq_remove_nonblock(mqd: MQd) -> Result<(MqAttr)> {
    let oldattr = try!(mq_getattr(mqd));
    let newattr = MqAttr::new(0, oldattr.mq_maxmsg, oldattr.mq_msgsize, oldattr.mq_curmsgs);
    mq_setattr(mqd, &newattr)
}